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Sample records for waste enhanced anaerobic

  1. Saponification of fatty slaughterhouse wastes for enhancing anaerobic biodegradability.

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    Battimelli, Audrey; Carrère, Hélène; Delgenès, Jean-Philippe

    2009-08-01

    The thermochemical pretreatment by saponification of two kinds of fatty slaughterhouse waste--aeroflotation fats and flesh fats from animal carcasses--was studied in order to improve the waste's anaerobic degradation. The effect of an easily biodegradable compound, ethanol, on raw waste biodegradation was also examined. The aims of the study were to enhance the methanisation of fatty waste and also to show a link between biodegradability and bio-availability. The anaerobic digestion of raw waste, saponified waste and waste with a co-substrate was carried out in batch mode under mesophilic and thermophilic conditions. The results showed little increase in the total volume of biogas, indicating a good biodegradability of the raw wastes. Mean biogas volume reached 1200 mL/g VS which represented more than 90% of the maximal theoretical biogas potential. Raw fatty wastes were slowly biodegraded whereas pretreated wastes showed improved initial reaction kinetics, indicating a better initial bio-availability, particularly for mesophilic runs. The effects observed for raw wastes with ethanol as co-substrate depended on the process temperature: in mesophilic conditions, an initial improvement was observed whereas in thermophilic conditions a significant decrease in biodegradability was observed.

  2. Aged refuse enhances anaerobic digestion of waste activated sludge.

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    Zhao, Jianwei; Gui, Lin; Wang, Qilin; Liu, Yiwen; Wang, Dongbo; Ni, Bing-Jie; Li, Xiaoming; Xu, Rui; Zeng, Guangming; Yang, Qi

    2017-10-15

    In this work, a low-cost alternative approach (i.e., adding aged refuse (AR) into waste activated sludge) to significantly enhance anaerobic digestion of sludge was reported. Experimental results showed that with the addition dosage of AR increasing from 0 to 400 mg/g dry sludge soluble chemical oxygen demand (COD) increased from 1150 to 5240 mg/L at the digestion time of 5 d, while the maximal production of volatile fatty acids (VFA) increased from 82.6 to 183.9 mg COD/g volatile suspended solids. Although further increase of AR addition decreased the concentrations of both soluble COD and VFA, their contents in these systems with AR addition at any concentration investigated were still higher than those in the blank, which resulted in higher methane yields in these systems. Mechanism studies revealed that pertinent addition of AR promoted solubilization, hydrolysis, and acidogenesis processes and did not affect methanogenesis significantly. It was found that varieties of enzymes and anaerobes in AR were primary reason for the enhancement of anaerobic digestion. Humic substances in AR benefited hydrolysis and acidogenesis but inhibited methanogenesis. The effect of heavy metals in AR on sludge anaerobic digestion was dosage dependent. Sludge anaerobic digestion was enhanced by appropriate amounts of heavy metals but inhibited by excessive amounts of heavy metals. The relative abundances of microorganisms responsible for sludge hydrolysis and acidogenesis were also observed to be improved in the system with AR addition, which was consistent with the performance of anaerobic digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Enhancement of anaerobic biodegradability of flower stem wastes with vegetable wastes by co-hydrolysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; HE Pinjing; L(U) Fan; SHAO Liming

    2008-01-01

    The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes.The experiments were carried out in batches.When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13,the overall hydrolysis rate increased by 8%,12%,and 2%according to the carbon,nitrogen,and total solid (TS) conversion rate,respeetively.While the dry weight ratio was designed as 1 to 3,there was a respective rise of 5%,15%,and 4% in the conversion rate of carbon,nitrogen,and TS.The enhancement of anaerobic hydrolysis from the mixed vegetable wastes and flower stems can be attributed to the formation of volatile fatty acids (VFA) and nutrient supplement like nitrogen content.The maximum VFA concentration can achieve 1.7 g/L owing to the rapid acidification of vegetable wastes,loosing the structure of lignocellulose materials.The statistic bivariate analysis revealed that the hydrolysis performance was significantly related to the physical and biochemical compositions of the feeding substrate.Especially,the soluble carbon concentration in the liquid was significantly positively correlated to the concentration of nitrogen and bemicellulose,and negatively correlated to the concentration of carbon and lignocellulose in the feeding substrate,suggesting that the regulation and control of feedstock can have an important influence on the anaerobic hydrolysis of organic wastes.

  4. Enhanced anaerobic digestion of food waste by thermal and ozonation pretreatment methods.

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    Ariunbaatar, Javkhlan; Panico, Antonio; Frunzo, Luigi; Esposito, Giovanni; Lens, Piet N L; Pirozzi, Francesco

    2014-12-15

    Treatment of food waste by anaerobic digestion can lead to an energy production coupled to a reduction of the volume and greenhouse gas emissions from this waste type. According to EU Regulation EC1774/2002, food waste should be pasteurized/sterilized before or after anaerobic digestion. With respect to this regulation and also considering the slow kinetics of the anaerobic digestion process, thermal and chemical pretreatments of food waste prior to mesophilic anaerobic digestion were studied. A series of batch experiments to determine the biomethane potential of untreated as well as pretreated food waste was carried out. All tested conditions of both thermal and ozonation pretreatments resulted in an enhanced biomethane production. The kinetics of the anaerobic digestion process were, however, accelerated by thermal pretreatment at lower temperatures (food waste, was obtained with thermal pretreatment at 80 °C for 1.5 h. On the basis of net energy calculations, the enhanced biomethane production could cover the energy requirement of the thermal pretreatment. In contrast, the enhanced biomethane production with ozonation pretreatment is insufficient to supply the required energy for the ozonator.

  5. Enhanced biogas production from anaerobic codigestion of solid waste by sonolysis.

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    Cesaro, Alessandra; Naddeo, Vincenzo; Amodio, Valeria; Belgiorno, Vincenzo

    2012-05-01

    This paper examines the effectiveness of sonolysis in improving the anaerobic biodegradability of the organic fraction of municipal solid waste coming from mechanical selection, thus enhancing biogas production and energy recovery as well. Methane yield of solid organic material anaerobic digestion is significantly affected by substrate availability that was evaluated, in this investigation, through organic matter solubilisation tests carried out at different conditions of ultrasound treatment. Results show that sonolysis can significantly improve the solubilisation of organic solid waste, thus allowing higher biogas production from anaerobic treatment of sonicated substrates. After 45 days, the biogas produced during anaerobic codigestion tests for the sonicated mixture was 24% higher than untreated one. Therefore, these results can lay the basis for the development of technologies useful to produce high biogas quantities, in order to improve clean energy generation from biowaste.

  6. Enhancing anaerobic digestion performance of crude lipid in food waste by enzymatic pretreatment.

    Science.gov (United States)

    Meng, Ying; Luan, Fubo; Yuan, Hairong; Chen, Xue; Li, Xiujin

    2017-01-01

    Three lipases were applied to hydrolyze the floatable grease (FG) in the food waste for eliminating FG inhibition and enhancing digestion performance in anaerobic process. Lipase-I, Lipase-II, and Lipase-III obtained from different sources were used. Animal fat (AF) and vegetable oil (VO) are major crude lipids in Chinese food waste, therefore, applied as substrates for anaerobic digestion tests. The results showed that Lipase-I and Lipase-II were capable of obviously releasing long chain fatty acid in AF, VO, and FG when hydrolyzed in the conditions of 24h, 1000-1500μL and 40-50°C. Compared to the untreated controls, the biomethane production rate were increased by 80.8-157.7%, 26.9-53.8%, and 37.0-40.7% for AF, VO, and FG, respectively, and the digestion time was shortened by 10-40d. The finding suggests that pretreating lipids with appropriate lipase could be one of effective methods for enhancing anaerobic digestion of food waste rich in crude lipid. Copyright © 2016. Published by Elsevier Ltd.

  7. Enhanced anaerobic digestion of waste activated sludge digestion by the addition of zero valent iron.

    Science.gov (United States)

    Feng, Yinghong; Zhang, Yaobin; Quan, Xie; Chen, Suo

    2014-04-01

    Anaerobic digestion is promising technology to recover energy from waste activated sludge. However, the sludge digestion is limited by its low efficiency of hydrolysis-acidification. Zero valent iron (ZVI) as a reducing material is expected to enhance anaerobic process including the hydrolysis-acidification process. Considering that, ZVI was added into an anaerobic sludge digestion system to accelerate the sludge digestion in this study. The results indicated that ZVI effectively enhanced the decomposition of protein and cellulose, the two main components of the sludge. Compared to the control test without ZVI, the degradation of protein increased 21.9% and the volatile fatty acids production increased 37.3% with adding ZVI. More acetate and less propionate are found during the hydrolysis-acidification with ZVI. The activities of several key enzymes in the hydrolysis and acidification increased 0.6-1 time. ZVI made the methane production raise 43.5% and sludge reduction ratio increase 12.2 percent points. Fluorescence in situ hybridization analysis showed that the abundances of hydrogen-consuming microorganisms including homoacetogens and hydrogenotrophic methanogens with ZVI were higher than the control, which reduced the H2 accumulation to create a beneficial condition for the sludge digestion in thermodynamics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Enhanced high-solids anaerobic digestion of waste activated sludge by the addition of scrap iron.

    Science.gov (United States)

    Zhang, Yaobin; Feng, Yinghong; Yu, Qilin; Xu, Zibin; Quan, Xie

    2014-05-01

    Anaerobic digestion of waste activated sludge usually requires pretreatment procedure to improve the bioavailability of sludge, which involves considerable energy and high expenditures. This study proposes a cost-effective method for enhanced anaerobic digestion of sludge without a pretreatment by directly adding iron into the digester. The results showed that addition of Fe(0) powder could enhance 14.46% methane yield, and Fe scrap (clean scrap) could further enhance methane yield (improving rate 21.28%) because the scrap has better mass transfer efficiency with sludge and liquid than Fe(0) powder. The scrap of Fe with rust (rusty scrap) could induce microbial Fe(III) reduction, which resulted in achieving the highest methane yield (improving rate 29.51%), and the reduction rate of volatile suspended solids (VSS) was also highest (48.27%) among Fe powder, clean scrap and rusty scrap. PCR-DGGE proved that the addition of rusty scrap could enhance diversity of acetobacteria and enrich iron-reducing bacteria to enhance degradation of complex substrates.

  9. Optimization of the anaerobic treatment of a waste stream from an enhanced oil recovery process.

    Science.gov (United States)

    Alimahmoodi, Mahmood; Mulligan, Catherine N

    2011-01-01

    The aim of this work was to optimize the anaerobic treatment of a waste stream from an enhanced oil recovery (EOR) process. The treatment of a simulated waste water containing about 150 mg chemical oxygen demand (COD)/L of total petroleum hydrocarbons (TPH) and the saturation level of CO2 was evaluated. A two-step anaerobic system was undertaken in the mesophilic temperature range (30-40°C). The method of evolutionary operation EVOP factorial design was used to optimize pH, temperature and organic loading rate with the target parameters of CO2 reduction and CH4 production in the first reactor and TPH removal in the second reactor. The results showed 98% methanogenic removal of CO2 and CH4 yield of 0.38 L/gCOD in the first reactor and 83% TPH removal in the second reactor. In addition to enhancing CO2 and TPH removal and CH4 production, application of this method showed the degree of importance of the operational variables and their interactive effects for the two reactors in series. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Enhanced mesophilic anaerobic digestion of food waste by thermal pretreatment: Substrate versus digestate heating.

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    Ariunbaatar, Javkhlan; Panico, Antonio; Yeh, Daniel H; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2015-12-01

    Food waste (FW) represents a source of high potential renewable energy if properly treated with anaerobic digestion (AD). Pretreating the substrates could yield a higher biomethane production in a shorter time. In this study, the effects of thermal (heating the FW in a separate chamber) and thermophilic (heating the full reactor content containing both FW and inoculum) pretreatments at 50, 60, 70 and 80°C prior to mesophilic AD were studied through a series of batch experiments. Pretreatments at a lower temperature (50°C) and a shorter time (55°C) and longer operating times (>12h) yielded higher soluble chemical oxygen demand (CODs), but had a negative effect on the methanogenic activity. The thermal pretreatments at the same conditions resulted in a lower solubilization of COD. Based on net energy calculations, the enhanced biomethane production is sufficient to heat up the FW for the thermal, but not for the thermophilic pretreatment.

  11. Enhancing anaerobic digestion of food waste through biochemical methane potential assays at different substrate: inoculum ratios.

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    Hobbs, Shakira R; Landis, Amy E; Rittmann, Bruce E; Young, Michelle N; Parameswaran, Prathap

    2017-06-28

    Food waste has a high energy potential that can be converted into useful energy in the form of methane via anaerobic digestion. Biochemical Methane Potential assays (BMPs) were conducted to quantify the impacts on methane production of different ratios of food waste. Anaerobic digester sludge (ADS) was used as the inoculum, and BMPs were performed at food waste:inoculum ratios of 0.42, 1.42, and 3.0g chemical oxygen demand/g volatile solids (VS). The 1.42 ratio had the highest CH4-COD recovery: 90% of the initial total chemical oxygen demand (TCOD) was from food waste, followed by ratios 0.42 and 3.0 at 69% and 57%, respectively. Addition of food waste above 0.42 caused a lag time for CH4 production that increased with higher ratios, which highlighted the negative impacts of overloading with food waste. The Gompertz equation was able to represent the results well, and it gave lag times of 0, 3.6 and 30days and maximum methane productions of 370, 910, and 1950mL for ratios 0.42, 1.42 and 3.0, respectively. While ratio 3.0 endured a long lag phase and low VSS destruction, ratio 1.42 achieved satisfactory results for all performance criteria. These results provide practical guidance on food-waste-to-inoculum ratios that can lead to optimizing methanogenic yield. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Synergistic effect of co-digestion to enhance anaerobic degradation of catering waste and orange peel for biogas production.

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    Anjum, Muzammil; Khalid, Azeem; Qadeer, Samia; Miandad, Rashid

    2017-09-01

    Catering waste and orange peel were co-digested using an anaerobic digestion process. Orange peel is difficult to degrade anaerobically due to the presence of antimicrobial agents such as limonene. The present study aimed to examine the feasibility of anaerobic co-digestion of catering waste with orange peel to provide the optimum nutrient balance with reduced inhibitory effects of orange peel. Batch experiments were conducted using catering waste as a potential substrate mixed in varying ratios (20-50%) with orange peel. Similar ratios were followed using green vegetable waste as co-substrate. The results showed that the highest organic matter degradation (49%) was achieved with co-digestion of catering waste and orange peel at a 50% mixing ratio (CF4). Similarly, the soluble chemical oxygen demand (sCOD) was increased by 51% and reached its maximum value (9040 mg l(-1)) due to conversion of organic matter from insoluble to soluble form. Biogas production was increased by 1.5 times in CF4 where accumulative biogas was 89.61 m(3) t(-1)substrate compared with 57.35 m(3) t(-1)substrate in the control after 80 days. The main reason behind the improved biogas production and degradation is the dilution of inhibitory factors (limonene), with subsequent provision of balanced nutrients in the co-digestion system. The tCOD of the final digestate was decreased by 79.9% in CF4, which was quite high as compared with 68.3% for the control. Overall, this study revealed that orange peel waste is a highly feasible co-substrate for anaerobic digestion with catering waste for enhanced biogas production.

  13. Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids.

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    Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

    2016-01-01

    In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

  14. Enhancing anaerobic digestion of high-pressure extruded food waste by inoculum optimization.

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    Kong, Xin; Xu, Shuang; Liu, Jianguo; Li, Huan; Zhao, Ke; He, Liang

    2016-01-15

    The inoculation for extruded food waste anaerobic digestion (AD) was optimized to improve methane (CH4) yield. The inoculum of acclimated anaerobic sludge resulted in high biodegradability, producing CH4 yields from 580 mLCH4 g(-1)·VSadded to 605 mLCH4 g(-1)·VSadded, with corresponding BDCH4 ranging from 90% to 94%. We also investigated inoculum to substrate ratios (ISRs). With regards to digested slurry as inoculum, we found that a decrease in ISR improved CH4 yield, while a lower ISR prolonged the lag time of the initial AD stage due to lipid inhibition caused by excessive food waste. These results demonstrate that minimal inocula are required to start the AD system for high-pressure extruded food waste because it is easily biodegraded. High ammonia concentration had a negative effect on CH4 production (i.e., when free ammonia nitrogen [FAN] increased from 20 to 30 mg L(-1) to 120-140 mg L(-1), the CH4 yield decreased by 25%), suggesting that FAN was a significant inhibitor in CH4 yield reduction. In terms of CH4 yield and lag time of the AD process, the optimal inoculation of digested slurry for the extruded food waste had an ISR of 0.33 with CH4 yield of 505 mLCH4 g(-1)VSadded, which was 20% higher than what was found for higher ISR controls of 2, 1 and 0.5.

  15. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate

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    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-01

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d‑1) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.

  16. Zero-valent iron enhanced methanogenic activity in anaerobic digestion of waste activated sludge after heat and alkali pretreatment.

    Science.gov (United States)

    Zhang, Yaobin; Feng, Yinghong; Quan, Xie

    2015-04-01

    Heat or alkali pretreatment is the effective method to improve hydrolysis of waste sludge and then enhance anaerobic sludge digestion. However the pretreatment may inactivate the methanogens in the sludge. In the present work, zero-valent iron (ZVI) was used to enhance the methanogenic activity in anaerobic sludge digester under two methanogens-suppressing conditions, i.e. heat-pretreatment and alkali condition respectively. With the addition of ZVI, the lag time of methane production was shortened, and the methane yield increased by 91.5% compared to the control group. The consumption of VFA was accelerated by ZVI, especially for acetate, indicating that the acetoclastic methanogenesis was enhanced. In the alkali-condition experiment, the hydrogen produced decreased from 27.6 to 18.8 mL when increasing the ZVI dosage from 0 to 10 g/L. Correspondingly, the methane yield increased from 1.9 to 32.2 mL, which meant that the H2-utilizing methanogenes was enriched. These results suggested that the addition of ZVI into anaerobic digestion of sludge after pretreated by the heat or alkali process could efficiently recover the methanogenic activity and increase the methane production and sludge reduction.

  17. Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

    Science.gov (United States)

    Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

    2016-02-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology.

  18. ENHANCED ANAEROBIC DIGESTION OF FOOD WASTE BY SUPPLEMENTING TRACE ELEMENTS: ROLE OF SELENIUM (VI AND IRON (II

    Directory of Open Access Journals (Sweden)

    Javkhlan eAriunbaatar

    2016-02-01

    Full Text Available This paper discusses the potential to enhance the anaerobic digestion of food waste FW by supplementing trace elements (Fe, Co, Ni, Zn, Mn, Cu, Se, and Mo individually as well as in cocktails. A series of batch experiments on the biomethane potential of synthetic food waste were performed with low (FW-A and high (FW-B trace element background concentrations prepared in, respectively, Delft (The Netherlands and Tampa (Florida, USA. The most effective trace elements for FW-A were Fe with an increase of 39.2 (± 0.6 % of biomethane production, followed by Se (34.1 ± 5.6 % increase, Ni (26.4 ± 0.2 % increase and Co (23.8 ± 0.2 % increase. For FW-B supplementing these trace elements did not result in enhancement of the biomethane production, except for Se. FW-B had a Se concentration of 1.3 (± 0. 5 µg/gTS, while it was below the detection limit for FW-A. Regardless of the FW source, Se resulted in 30 – 35% increase of biomethane production at a concentration range of 25-50 µg/L (0.32 – 0.63 µM. Volatile fatty acids analysis revealed that TE supplementation enhances their consumption, thus yielding a higher biomethane production. Moreover, additional experiments on sulfide inhibition showed the enhancing effects of trace elements on the anaerobic digestion of food waste were not related with sulfide toxicity, but with the enzymatic reactions and/or microbial biomass aggregation.

  19. Carbon capture and biogas enhancement by carbon dioxide enrichment of anaerobic digesters treating sewage sludge or food waste.

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    Bajón Fernández, Y; Soares, A; Villa, R; Vale, P; Cartmell, E

    2014-05-01

    The increasing concentration of carbon dioxide (CO2) in the atmosphere and the stringent greenhouse gases (GHG) reduction targets, require the development of CO2 sequestration technologies applicable for the waste and wastewater sector. This study addressed the reduction of CO2 emissions and enhancement of biogas production associated with CO2 enrichment of anaerobic digesters (ADs). The benefits of CO2 enrichment were examined by injecting CO2 at 0, 0.3, 0.6 and 0.9 M fractions into batch ADs treating food waste or sewage sludge. Daily specific methane (CH4) production increased 11-16% for food waste and 96-138% for sewage sludge over the first 24h. Potential CO2 reductions of 8-34% for sewage sludge and 3-11% for food waste were estimated. The capacity of ADs to utilise additional CO2 was demonstrated, which could provide a potential solution for onsite sequestration of CO2 streams while enhancing renewable energy production.

  20. Anaerobic co-digestion of municipal organic wastes and pre-treatment to enhance biogas production from waste.

    Science.gov (United States)

    Li, Chenxi; Champagne, Pascale; Anderson, Bruce C

    2014-01-01

    Co-digestion and pre-treatment have been recognized as effective, low-cost and commercially viable approaches to reduce anaerobic digestion process limitations and improve biogas yields. In our previous batch-scale study, fat, oil, and grease (FOG) was investigated as a suitable potential co-substrate, and thermo-chemical pre-treatment (TCPT) at pH = 10 and 55 °C improved CH4 production from FOG co-digestions. In this project, co-digestions with FOG were studied in bench-scale two-stage thermophilic semi-continuous flow co-digesters with suitable TCPT (pH = 10, 55 °C). Overall, a 25.14 ± 2.14 L/d (70.2 ± 1.4% CH4) biogas production was obtained, which was higher than in the two-stage system without pre-treatment. The results could provide valuable fundamental information to support full-scale investigations of anaerobic co-digestion of municipal organic wastes.

  1. Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

    Institute of Scientific and Technical Information of China (English)

    Yongzhi Chi; Yuyou Li; Xuening Fei; Shaopo Wang; Hongying Yun

    2011-01-01

    Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency.Uniform design was applied to determine the combination of target temperature (110-210℃),microwave holding time (1-51 min),and NaOH dose (0-2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization.Maximum solubilization ratio (85.1%) of VSS was observed at 210℃ with 0.2 g-NaOH/g-SS and 35 min holding time.The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP).Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge.The highest CMP was a 27% improvement over the control.In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge,a semi-continuous thennophilic reactor fed with pretreated TWAS without neutralization (at 170℃ with 1 rain holding time and 0.05 g NaOH/g SS) was stable and functioned well,with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%,respectively,which were higher than those of the control system.Additionally,methane yields (L@STP/g-CODadded,at standard temperature and pressure (STP) conditions of 0℃ and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%,respectively,compared to the control reactor.

  2. Anaerobic co-digestion of food waste and chemically enhanced primary-treated sludge under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Obulisamy, Parthiba Karthikeyan; Chakraborty, Debkumar; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-12-01

    Anaerobic co-digestion of food waste with primary sewage sludge is beneficial for urban centers, while the optimized conditions reported in the literature are not locally suitable for Hong Kong. Therefore, the present study was aimed to develop an optimized mixing ratio of food waste to chemically enhanced primary-treated sewer sludge (CEPT) for co-digestion using batch tests under mesophilic (37°C) and thermophilic (55°C) conditions. The mixing ratios of 1:1, 1:2, 1:3, 2:1 and 3:1 (v v(-1)) of food waste to CEPT sludge was tested under the following conditions: temperature - 35°C and 55°C; pH - not regulated; agitation - 150 rpm and time - 20 days. The thermophilic incubations led a good hydrolysis rate and 2-12-fold higher enzyme activities than in mesophilic incubations for different mixing ratios. While the acidogenesis were found retarded that leading to 'sour and stuck' digestion for all mixing ratio of food waste to CEPT sludge from thermophilic incubations. The measured zeta potential was most favourable (-5 to -16.8 mV) for methane production under thermophilic incubations; however the CH4 recovery was less than that in mesophilic incubations. The results suggested that the quick hydrolysis and subsequent acid accumulation under thermophilic incubation lead to inhibited methanogenesis at the early stage than in mesophilic systems. It is concluded that buffer addition is therefore required for any mixing ratio of food waste to CEPT sludge for improved CH4 recovery for both mesophilic and thermophilic operations.

  3. Towards a sustainable paradigm of waste-to-energy process: Enhanced anaerobic digestion of sludge with woody biochar

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yanwen; Linville, Jessica L.; Ignacio-de Leon, Patricia Anne A.; Schoene, Robin P.; Urgun-Demirtas, Meltem

    2016-11-01

    This study presents an integrated waste-to-energy process, using two waste streams, sludge generated from the municipal wastewater treatment plants (WWTPs) and biochar generated from the biomass gasification systems, to produce fungible biomethane and nutrient-rich digestate with fertilizer value. Two woody biochar, namely pinewood (PBC) and white oak biochar (WOBC) were used as additives during anaerobic digestion (AD) of WWTP sludge to enhance methane production at mesophilic and thermophilic temperatures. The PBC and WOBC have porous structure, large surface area and desirable chemical properties to be used as AD amendment material to sequester CO2 from biogas in the digester. The biochar-amended digesters achieved average methane content in biogas of up to 92.3% and 79.0%, corresponding to CO2 sequestration by up to 66.2% and 32.4% during mesophilic and thermophilic AD, respectively. Biochar addition enhanced process stability by increasing the alkalinity, but inhibitory effects were observed at high dosage. It also alleviated free ammonia inhibition by up to 10.5%. The biochar-amended digesters generated digestate rich in macro- and micronutrients including K (up to 300 m/L), Ca (up to 750 mg/L), Mg (up to 1800 mg/L) and Fe (up to 390 mg/L), making biochar-amended digestate a potential alternative used as agricultural lime fertilizer.

  4. Thermophilic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with food waste (FW): Enhancement of bio-hydrogen production.

    Science.gov (United States)

    Angeriz-Campoy, Rubén; Álvarez-Gallego, Carlos J; Romero-García, Luis I

    2015-10-01

    Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added).

  5. Anaerobic co-digestion of the organic fraction of municipal solid waste with FOG waste from a sewage treatment plant: recovering a wasted methane potential and enhancing the biogas yield.

    Science.gov (United States)

    Martín-González, L; Colturato, L F; Font, X; Vicent, T

    2010-10-01

    Anaerobic digestion is applied widely to treat the source collected organic fraction of municipal solid wastes (SC-OFMSW). Lipid-rich wastes are a valuable substrate for anaerobic digestion due to their high theoretical methane potential. Nevertheless, although fat, oil and grease waste from sewage treatment plants (STP-FOGW) are commonly disposed of in landfill, European legislation is aimed at encouraging more effective forms of treatment. Co-digestion of the above wastes may enhance valorisation of STP-FOGW and lead to a higher biogas yield throughout the anaerobic digestion process. In the present study, STP-FOGW was evaluated as a co-substrate in wet anaerobic digestion of SC-OFMSW under mesophilic conditions (37 degrees C). Batch experiments carried out at different co-digestion ratios showed an improvement in methane production related to STP-FOGW addition. A 1:7 (VS/VS) STP-FOGW:SC-OFMSW feed ratio was selected for use in performing further lab-scale studies in a 5L continuous reactor. Biogas yield increased from 0.38+/-0.02 L g VS(feed)(-1) to 0.55+/-0.05 L g VS(feed)(-1) as a result of adding STP-FOGW to reactor feed. Both VS reduction values and biogas methane content were maintained and inhibition produced by long chain fatty acid (LCFA) accumulation was not observed. Recovery of a currently wasted methane potential from STP-FOGW was achieved in a co-digestion process with SC-OFMSW.

  6. Optimization of micronutrient supplement for enhancing biogas production from food waste in two-phase thermophilic anaerobic digestion.

    Science.gov (United States)

    Menon, Ajay; Wang, Jing-Yuan; Giannis, Apostolos

    2017-01-01

    The aim of this study was to enhance the biogas productivity of two-phase thermophilic anaerobic digestion (AD) using food waste (FW) as the primary substrate. The influence of adding four trace metals (Ca, Mg, Co, and Ni) as micronutrient supplement in the methanogenic phase of the thermophilic system was investigated. Initially, Response Surface Methodology (RSM) was applied to determine the optimal concentration of micronutrients in batch experiments. The results showed that optimal concentrations of 303, 777, 7 and 3mg/L of Ca, Mg, Co and Ni, respectively, increased the biogas productivity as much as 50% and significantly reduced the processing time. The formulated supplement was tested in continuous two-phase thermophilic AD system with regard to process stability and productivity. It was found that a destabilized thermophilic AD process encountering high VFA accumulation recovered in less than two weeks, while the biogas production was improved by 40% yielding 0.46L CH4/gVSadded/day. There was also a major increase in soluble COD utilization upon the addition of micronutrient supplement. The results of this study indicate that a micronutrient supplement containing Ca, Mg, Co and Ni could probably remedy any type of thermophilic AD process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Effect of hydrothermal pre-treatment (HTP) on poultry slaughterhouse waste (PSW) sludge for the enhancement of the solubilization, physical properties, and biogas production through anaerobic digestion.

    Science.gov (United States)

    Park, Seyong; Yoon, Young-Man; Han, Seong Kuk; Kim, Daegi; Kim, Ho

    2017-06-01

    This study is an assessment of the hydrothermal pre-treatment (HTP) of poultry slaughterhouse waste (PSW) sludge for the enhancement of the solubilization, physical properties, and biogas production through anaerobic digestion. This assessment was carried out to ascertain the optimal HTP temperature. The solubilization and physical properties efficacy was investigated by capillary suction time (CST), time to filter (TTF), and particle size. In addition, the anaerobic digestion was investigated through biochemical methane potential (BMP) tests and subsequent statistical analysis using the modified Gompertz model. HTP was found to have improved the solubilization of the PSW sludge with increasing HTP temperature. In addition, the results of the CST, TTF, and particle size decreased with increasing HTP temperature. These results of the assessment that was conducted in this study confirm that the HTP process indeed modifies the physical properties of PSWs to enhance the solubilization of organic solids. Nevertheless, the results of the BMP tests and the modified Gompertz model analysis show that the optimal HTP temperature of PSWs for anaerobic digestion is 190°C. These findings show that to achieve high conversion efficiency, an accurately designed pre-treatment step must be included in the overall anaerobic digestion process for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Comparison of mechanical pretreatment methods for the enhancement of anaerobic digestion of pulp and paper waste activated sludge.

    Science.gov (United States)

    Elliott, Allan; Mahmood, Talat

    2012-06-01

    The conventional anaerobic digestion process, requiring long solids retention times (SRTs) to digest solids, is currently viewed as impractical for the pulp and paper industry because of high capital costs associated with the construction of new digesters. Recent developments in sludge solubilization technology could be promising in reducing digester size, which also allows for the potential use of decommissioned tanks, both of which can reduce the capital cost. Three pretreatment technologies for use with anaerobic digestion were tested on laboratory-scale to investigate their feasibility. The SRTs in all three digesters systematically decreased from 20 to 3 days. The reference digester was fed waste activated sludge (WAS) to serve as the control at the same SRTs. The other digesters were fed WAS that had been preconditioned using mechanical shearing, sonication, or high-pressure homogenization technology. Anaerobic digestion with high-pressure homogenization produced as much methane at 3-day mean SRT as that from the reference digester operated at 20-day SRT. Therefore, a new digester can theoretically be 85% smaller than a conventional digester. An added benefit of WAS to methane conversion is the recovery of nutrients nitrogen and phosphorus.

  9. High pressure homogenization and two-phased anaerobic digestion for enhanced biogas conversion from municipal waste sludge.

    Science.gov (United States)

    Wahidunnabi, Abdullahil K; Eskicioglu, Cigdem

    2014-12-01

    This study compared advanced anaerobic digestion combining two-phased anaerobic digestion (2PAD) with high pressure homogenization (HPH) pretreatment to conventional anaerobic digestion of municipal sludge at laboratory scale. The study began with examination of thickened waste activated sludge (TWAS) solubilization due to HPH pretreatment at different pressure (0-12,000 psi) and chemical dose (0.009-0.036 g NaOH/g total solids). Homogenizing pressure was found as the most significant factor (p-value production (0.61-1.32 L CH4/Ldigester-d) and VS removals (43-64%). Thermophilic control, 2PAD and HPH + 2PAD systems resulted in significant pathogen removals meeting Class A biosolids requirements according to Organic Matter Recycling Regulations (OMRR) of British Columbia (BC) at 20 d SRT. Energy analysis indicated that all the digestion scenarios attained positive energy balance with 2PAD system operated at 20 d SRT producing the maximum net energy of 4.76 GJ/tonne CODadded.

  10. Enhanced hydrolysis and methane yield by applying microaeration pretreatment to the anaerobic co-digestion of brown water and food waste

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jun Wei [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, Singapore 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Wang, Jing-Yuan, E-mail: jywang@ntu.edu.sg [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, Singapore 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2013-04-15

    Highlights: ► Microaeration pretreatment was effective for brown water and food waste mixture. ► The added oxygen was consumed fully by facultative microorganisms. ► Enhanced solubilization, acidification and breakdown of SCFAs to acetate. ► Microaeration pretreatment improved methane yield by 10–21%. ► Nature of inoculum influenced the effects of microaeration. - Abstract: Microaeration has been used conventionally for the desulphurization of biogas, and recently it was shown to be an alternative pretreatment to enhance hydrolysis of the anaerobic digestion (AD) process. Previous studies on microaeration pretreatment were limited to the study of substrates with complex organic matter, while little has been reported on its effect on substrates with higher biodegradability such as brown water and food waste. Due to the lack of consistent microaeration intensities, previous studies were not comparable and thus inconclusive in proving the effectiveness of microaeration to the overall AD process. In this study, the role of microaeration pretreatment in the anaerobic co-digestion of brown water and food waste was evaluated in batch-tests. After a 4-day pretreatment with 37.5 mL-O{sub 2}/L{sub R}-d added to the liquid phase of the reactor, the methane production of substrates were monitored in anaerobic conditions over the next 40 days. The added oxygen was consumed fully by facultative microorganisms and a reducing environment for organic matter degradation was maintained. Other than higher COD solubilization, microaeration pretreatment led to greater VFA accumulation and the conversion of other short chain fatty acids to acetate. This could be due to enhanced activities of hydrolytic and acidogenic bacteria and the degradation of slowly biodegradable compounds under microaerobic conditions. This study also found that the nature of inoculum influenced the effects of microaeration as a 21% and 10% increase in methane yield was observed when pretreatment was

  11. Anaerobic digester for treatment of organic waste

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, V. K. [Indian Insitute of Technology, Delhi (India)]|[ENEA, Centro Ricerche Trisaia, Matera (Italy); Fortuna, F.; Canditelli, M.; Cornacchia, G. [ENEA, Centro Ricerche Trisaia, Matera (Italy). Dipt. Ambiente; Farina, R. [ENEA, centro Ricerche ``Ezio Clementel``, Bologna (Italy). Dipt. Ambiente

    1997-09-01

    The essential features of both new and more efficient reactor systems and their appropriate applications for various organic waste management situations, description of several working plants are discussed in the present communication. It is hoped that significant development reported here would be useful in opening a new vista to the application of anaerobic biotechnology for the waste treatment of both low/high organic strength and specialized treatment for toxic substances, using appropriate anaerobic methods.

  12. Simultaneous addition of zero-valent iron and activated carbon on enhanced mesophilic anaerobic digestion of waste-activated sludge.

    Science.gov (United States)

    Wang, Tongyu; Qin, Yujie; Cao, Yan; Han, Bin; Ren, Junyi

    2017-08-11

    The performance of biogas generation and sludge degradation was studied under different zero-valent iron/activated carbon (ZVI/AC) ratios in detail in mesophilic anaerobic digestion of sludge. A good enhancement of methane production was obtained at the 10:1 ZVI/AC ratio, and the cumulative methane production was 132.1 mL/g VS, 37.6% higher than the blank. The methane content at the 10:1 ZVI/AC ratio reached 68.8%, which was higher than the blank (55.2%) and the sludge-added AC alone (59.6%). For sludge degradation, the removal efficiencies of total chemical oxygen demand (TCOD), proteins, and polysaccharides were all the highest at the 10:1 ZVI/AC ratio. The concentration of available phosphorus (AP) decreased after anaerobic digestion process. On the other hand, the concentrations of available nitrogen (AN) and available potassium (AK) increased after the anaerobic digestion process and showed a gradually decreasing trend with increasing ZVI/AC ratio. The concentrations of AN and AK were 2303.1-4200.3 and 274.7-388.3 mg/kg, showing a potential for land utilization.

  13. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process

    DEFF Research Database (Denmark)

    Luo, Gang; Xie, Li; Zhou, Qi

    2011-01-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single......-stage methanogenic process (HRT 15d) under organic loading rate (OLR) 3gVS/(Ld). The two-stage process was still stable when the OLR was increased to 4.5gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRThydrogen:HRTmethane ratio of the two-stage process from 3...

  14. Anaerobic Digestion of Piggery Waste

    NARCIS (Netherlands)

    Velsen, van A.F.M.

    1981-01-01

    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes an

  15. Enhanced anaerobic digestion of food waste by trace metal elements supplementation and reduced metals dosage by green chelating agent [S, S]-EDDS via improving metals bioavailability.

    Science.gov (United States)

    Zhang, Wanli; Zhang, Lei; Li, Aimin

    2015-11-01

    This study aimed at investigating the effects of trace metals on methane production from food waste and examining the feasibility of reducing metals dosage by ethylenediamine-N,N'-disuccinic acid (EDDS) via improving metals bioavailability. The results indicated that the effects of metal elements highly depended on the supplemental concentrations. Trace metals supplemented under moderate concentrations greatly enhanced the methane yield. However, the excessive supplementation of Fe (1000 mg/L) and Ni (50 mg/L) exhibited the obvious toxicity to methanogens. The combinations of trace metals exhibited remarkable synergistic effects. The supplementation of Fe (100 mg/L) + Co (1 mg/L) + Mo (5 mg/L) + Ni (5 mg/L) obtained the greatest methane yield of 504 mL/g VSadded and the highest increment of 35.5% compared to the reactor without metals supplementation (372 mL/g VSadded). The changes of metals speciation showed the reduction of metals bioavailability during anaerobic digestion, which might weaken the stimulative effects of trace metals. However, the addition of EDDS improved metals bioavailability for microbial uptake and stimulated the activity of methanogens, and therefore, strengthened the stimulative effects of metals on anaerobic digestion of food waste. The batch and semi-continuous experiments confirmed that the addition of EDDS (20 mg/L) bonded to trace metals prior to their supplementation could obtain a 50% reduction of optimal metals dosage. This study provided a feasible method to reduce trace metals dosage without the degeneration of process performance of anaerobic digestion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process.

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zhou, Qi; Angelidaki, Irini

    2011-09-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single-stage methanogenic process (HRT 15 d) under organic loading rate (OLR) 3 gVS/(L d). The two-stage process was still stable when the OLR was increased to 4.5 gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRT(hydrogen):HRT(methane) ratio of the two-stage process from 3:12 to 1:14, 6.7%, more energy could be obtained. Microbial community analysis indicated that the dominant bacterial species were different in the hydrogen reactors (Thermoanaerobacterium thermosaccharolyticum-like species) and methane reactors (Clostridium thermocellum-like species). The changes of substrates and HRT did not change the dominant species. The archaeal community structures in methane reactors were similar both in single- and two- stage reactors, with acetoclastic methanogens Methanosarcina acetivorans-like organisms as the dominant species.

  17. Ultrasonic treatment to improve anaerobic digestibility of dairy waste streams.

    Science.gov (United States)

    Palmowski, L; Simons, L; Brooks, R

    2006-01-01

    The dairy-processing industry generates various types of organic wastes, which are utilised as stock feed, for anaerobic digestion, spread on land or alternatively land-filled at high costs. Owing to the generation of renewable energy, anaerobic digestion is an attractive option for many factories. To enhance the biological degradation process, a mechanical disintegration of various waste dairy streams was undertaken. While the successful application of ultrasonic treatment has been reported for various municipal waste streams, limited information was available for dairy industry applications. The results of this study showed that ultrasonic treatment can improve the digestibility of the more problematic dairy waste streams, such as sludges, by breaking down micro-organisms' cell walls and releasing soluble cell compounds. For more soluble streams, such as dairy factory effluent, an increased gas production was observed and attributed to the reduced particle size of the fat globules.

  18. Anaerobic co-digestion of organic wastes

    OpenAIRE

    2009-01-01

    Tese de doutoramento em Engenharia Química e Biológica Anaerobic digestion is an already established process but the increasing need of bio‐waste recovery has determined the emergence of new substrates, revamping the research in this field. Contrary to some other European countries, in Portugal this technology is still scarcely in use. Nonetheless, the current legislation endorses this application as a waste management and as an energy recovery process. The rapid growth of the ...

  19. Simultaneous enhancement of methane production and methane content in biogas from waste activated sludge and perennial ryegrass anaerobic co-digestion: The effects of pH and C/N ratio.

    Science.gov (United States)

    Dai, Xiaohu; Li, Xiaoshuai; Zhang, Dong; Chen, Yinguang; Dai, Lingling

    2016-09-01

    It is necessary to find an appropriate strategy to simultaneously enhance the methane production and methane content in biogas from waste activated sludge (WAS) and grass co-digestion. In this study an efficient strategy, i.e., adjusting the initial pH 12 and C/N ratio 17/1, for simultaneous enhancement of methane production and methane content in biogas from WAS and perennial ryegrass co-digestion was reported. Experimental results indicated that the maximal methane production was 310mL/gVSadd at the optimum conditions after 30-d anaerobic digestion, which was, respectively, about 1.5- and 3.8-fold of the sole WAS and sole perennial ryegrass anaerobic digestion. Meanwhile, the methane content in biogas was about 74%, which was much higher than that of sole WAS (64%) or sole perennial ryegrass (54%) anaerobic digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Anaerobic composting of pyrethrum waste with and without effective ...

    African Journals Online (AJOL)

    user

    laboratory scale experiment involved composting of the waste as substrate mixed with EM at different .... The arrangement consists of 5 L plastic cane for anaerobic .... and Documentation Project on Recycling of Domestic Solid Waste.

  1. Thermochemical Pretreatment for Anaerobic Digestion of Sorted Waste

    Science.gov (United States)

    Hao, W.; Hongtao, W.

    2008-02-01

    The effect of alkaline hydrothermal pre-treatment for anaerobic digestion of mechanically-sorted municipal solid waste (MSW) and source-sorted waste was studied. Waste was hydrothermally pre-treated in dilute alkali solution. Hydrolysis product was incubated in 500 ml saline bottle to determine methane potential (MP) under mesospheric anaerobic conditions. Optimum reaction condition obtained in the study is 170 °C at the dose of 4 g NaOH/100 g solid for one hour. Soluble COD was 13936 mg/L and methane yield was 164 ml/g VS for 6 days incubation at optimum conditions. More than 50% biogas increase was achieved over the control, and methane conversion ratio on carbon basis was enhanced to 30.6%. The digestion period was less than 6 days when pre-treatment temperature was above 130 °C. The organic part of sorted waste is mainly constituted of kitchen garbage and leaf. Model kitchen garbage was completely liquidized at 130 °C for one hour and the methane yield was 276 ml/g VS. Addition of alkali enhance hydroxylation rate and methane yield slightly. The biogas potential of leaf could be observed by pre-treatment above 150 °C under alkaline condition.

  2. Enhancing biogas production from anaerobic biodegradation of the organic fraction of municipal solid waste through leachate blending and recirculation.

    Science.gov (United States)

    Nair, Arjun; Sartaj, Majid; Kennedy, Kevin; Coelho, Nuno M G

    2014-10-01

    Leachate recirculation has a profound advantage on biodegradation of the organic fraction of municipal solid waste in landfills. Mature leachate from older sections of landfills (>10 years) and young leachate were blended and added to organic fraction of municipal solid waste in a series of biomethane potential assay experiments with different mixing ratios of mature and young leachate and their effect on biogas production was monitored. The improvement in biogas production was in the range of 19%-41% depending on the ratio of mixing old and new leachate. The results are conclusive that the biogas generation could be improved by blending the old and new leachate in a bioreactor landfill system as compared with a conventional system employed in bioreactor landfills today for recirculating the same age leachate.

  3. Targeted modification of organic components of municipal solid waste by short-term pre-aeration and its enhancement on anaerobic degradation in simulated landfill bioreactors.

    Science.gov (United States)

    Ni, Zhe; Liu, Jianguo; Girotto, Francesca; Cossu, Raffaello; Qi, Guangxia

    2016-09-01

    Pre-aeration is effective on regulating subsequent anaerobic degradation of municipal solid waste (MSW) with high organic fractions during landfilling. The strength of pre-aeration should be optimized to intentionally remove some easily biodegradable fractions while conserve bio-methane potential as much as possible. This study investigates the evolution of organic components in MSW during 2-14days pre-aeration process and its impacts on subsequent anaerobic degradation in simulated landfill bioreactors. Results showed that a 6-day pre-aeration enabled to develop a thermophilic stage, which significantly accelerated biodegradation of organics except lignocelluloses, with removal rates of 42.8%, 76.7% and 25.1% for proteins, carbohydrates and lipids, respectively. Particularly, ammonia from accelerated ammonification in the thermophilic stage neutralized VFAs generated from anaerobic landfilling. As a result, the MSW with 6-day pre-aeration obtained the highest methane yield 123.4NL/kg dry matter. Therefore, it is recommended to interrupt pre-aeration before its cooling stage to switch to anaerobic landfilling.

  4. A comprehensive review on food waste anaerobic digestion: Research updates and tendencies.

    Science.gov (United States)

    Ren, Yuanyuan; Yu, Miao; Wu, Chuanfu; Wang, Qunhui; Gao, Ming; Huang, Qiqi; Liu, Yu

    2017-09-20

    Anaerobic digestion has been practically applied in agricultural and industrial waste treatment and recognized as an economical-effective way for food waste disposal. This paper presented an overview on the researches about anaerobic digestion of food waste. Technologies (e.g., pretreatment, co-digestion, inhibition and mitigation, anaerobic digestion systems, etc.) were introduced and evaluated on the basis of bibliometric analysis. Results indicated that ethanol and aerobic prefermentation were novel approaches to enhance substrates hydrolysis and methane yield. With the promotion of resource recovery, more attention should be paid to biorefinery technologies which can produce more useful products toward zero emissions. Furthermore, a technological route for food waste conversion based on anaerobic digestion was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Biohydrogen production by anaerobic fermentation of waste. Final project report

    Energy Technology Data Exchange (ETDEWEB)

    Karakashev, D.; Angelidaki, I.

    2009-01-15

    The objective of this project was to investigate and increase dark fermentative hydrogen production from organic wastes by optimizing important process parameters (reactor type, pH, temperature, organic loading, retention time, inoculation strategy, microbial composition). Labscale experiments were carried out at the Department of Environmental Engineering, Technical University of Denmark. A two steps process for hydrogen production in the first step and methane production in the second step in serial connected fully mixed reactors was developed and could successfully convert organic matter to approx. 20-25 % hydrogen and 15-80 % to methane. Sparging with methane produced in the second stage could significantly increase the hydrogen production. Additionally it was shown that upflow anaerobic sludge blanket (UASB) reactor system was very promising for high effective biohydrogen production from glucose at 70 deg C. Glucose-fed biofilm reactors filled with plastic carriers demonstrated high efficient extreme thermophilic biohydrogen production with mixed cultures. Repeated batch cultivations via exposure of the cultures to increased concentrations of household solid waste was found to be most useful method to enhance hydrogen production rate and reduce lag phase of extreme thermophilic fermentation process. Low level of pH (5.5) at 3-day HRT was enough to inhibit completely the methanogenesis and resulted in stable extreme thermophilic hydrogen production. Homoacetogenisis was proven to be an alternative competitor to biohydrogen production from organic acids under thermophilic (55 deg. C) conditions. With respect to microbiology, 16S rRNA targeted oligonucleotide probes were designed to monitor the spatial distribution of hydrogen producing bacteria in sludge and granules from anaerobic reactors. An extreme thermophilic (70 deg. C), strict anaerobic, mixed microbial culture with high hydrogen producing potential was enriched from digested household waste. Culture

  6. Renewable Energy Production from DoD Installation Solid Wastes By Anaerobic Digestion

    Science.gov (United States)

    2016-08-06

    have required more sustainable use of energy . Renewable Energy Production From DoD Installation Solid Wastes by Anaerobic Digestion 9 June 2016...Schafer, P., D. Trueblood, K. Fonda, and C. Lekven. 2007. Grease Processing for Renewable Energy , Profit, Sustainability , and Environmental Enhancement...Demirul. 2013. Ammonia inhibition in anaerobic digestion: A review . Process Biochemistry 48: 901-911. Renewable Energy Production From DoD

  7. BIOESTABILIZATION ANAEROBIC SOLID WASTE ORGANIC:QUANTITATIVE ASPECTS

    Directory of Open Access Journals (Sweden)

    Valderi Duarte Leite

    2015-01-01

    Full Text Available It is estimated that in Brazil, the municipal solid waste produced are constituted on average 55% of fermentable organic solid waste and that this quantity can be applied in aerobic or anaerobic stabilization process. Anaerobic digestion is an important alternative for the treatment of different types of potentially fermentable waste, considering providing an alternative source of energy that can be used to replace fossil fuels. To perform the experimental part of this work was constructed and monitored an experimental system consisting of an anaerobic batch reactor, shredding unit of fermentable organic wastes and additional devices. Fermentable organic wastes consisted of leftover fruits and vegetables and were listed in EMPASA (Paraibana Company of Food and Agricultural Services, located in the city of Campina Grande- PB. The residues were collected and transported to the Experimental Station Biological Sewage Treatment (EXTRABES where they were processed and used for substrate preparation. The substrate consisted of a mixture of fermentable organic waste, more anaerobic sewage sludge in the proportion of 80 and 20 % respectively. In the specific case of this study, it was found that 1m3 of substrate concentration of total COD equal to 169 g L-1, considering the reactor efficiency equal to 80 %, the production of CH4 would be approximately 47.25 Nm3 CH4. Therefore, fermentable organic waste, when subjected to anaerobic treatment process produces a quantity of methane gas in addition to the partially biostabilized compound may be applied as a soil conditioning agent.

  8. Enhancement in hydrogen production by thermophilic anaerobic co-digestion of organic fraction of municipal solid waste and sewage sludge--optimization of treatment conditions.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Angériz Campoy, Rubén; Álvarez-Gallego, C J; Romero García, L I

    2014-07-01

    Batch dry-thermophilic anaerobic co-digestion (55°C) of organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS) for hydrogen production was studied under several sludge combinations (primary sludge, PS; waste activated sludge, WAS; and mixed sludge, MS), TS concentrations (10-25%) and mixing ratios of OFMSW and SS (1:1, 2.5:1, 5:1, 10:1). The co-digestion of OFMSW and SS showed a 70% improvement in hydrogen production rate over the OFMSW fermentation only. The co-digestion of OFMSW with MS showed 47% and 115% higher hydrogen production potential as compared with OFMSW+PS and OFMSW+WAS, respectively. The maximum hydrogen yield of 51 mL H2/g VS consumed was observed at TS concentration of 20% and OFMSW to MS mixing ratio of 5:1, respectively. The acetic and butyric acids were the main acids in VFAs evolution; however, the higher butyric acid evolution indicated that the H2 fermentation was butyrate type fermentation.

  9. Biogas energy production from tropical biomass wastes by anaerobic digestion

    Science.gov (United States)

    Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass, and food w...

  10. Anaerobic co-digestion of food waste and landfill leachate in single-phase batch reactors

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Xiaofeng; Zhu, Shuangyan; Zhong, Delai; Zhu, Jingping, E-mail: jpzhuhust@163.com; Liao, Li, E-mail: liaoli2003@126.com

    2014-11-15

    Highlights: • Anaerobic co-digestion strategy for food waste treatment at OLR 41.8 g VS/L. • A certain amount of raw leachate effectively relieved acidic inhibition. • The study showed that food waste was completely degraded. - Abstract: In order to investigate the effect of raw leachate on anaerobic digestion of food waste, co-digestions of food waste with raw leachate were carried out. A series of single-phase batch mesophilic (35 ± 1 °C) anaerobic digestions were performed at a food waste concentration of 41.8 g VS/L. The results showed that inhibition of biogas production by volatile fatty acids (VFA) occurred without raw leachate addition. A certain amount of raw leachate in the reactors effectively relieved acidic inhibition caused by VFA accumulation, and the system maintained stable with methane yield of 369–466 mL/g VS. Total ammonia nitrogen introduced into the digestion systems with initial 2000–3000 mgNH{sub 4}–N/L not only replenished nitrogen for bacterial growth, but also formed a buffer system with VFA to maintain a delicate biochemical balance between the acidogenic and methanogenic microorganisms. UV spectroscopy and fluorescence excitation–emission matrix spectroscopy data showed that food waste was completely degraded. We concluded that using raw leachate for supplement water addition and pH modifier on anaerobic digestion of food waste was effective. An appropriate fraction of leachate could stimulate methanogenic activity and enhance biogas production.

  11. Assessment of anaerobic biodegradability of five different solid organic wastes

    Science.gov (United States)

    Kristanto, Gabriel Andari; Asaloei, Huinny

    2017-03-01

    The concept of waste to energy emerges as an alternative solution to increasing waste generation and energy crisis. In the waste to energy concept, waste will be used to produce renewable energy through thermochemical, biochemical, and physiochemical processes. In an anaerobic digester, organic matter brake-down due to anaerobic bacteria produces methane gas as energy source. The organic waste break-down is affected by various characteristics of waste components, such as organic matter content (C, N, O, H, P), solid contents (TS and VS), nutrients ratio (C/N), and pH. This research aims to analyze biodegradability and potential methane production (CH4) from organic waste largely available in Indonesia. Five solid wastes comprised of fecal sludge, cow rumen, goat farm waste, traditional market waste, and tofu dregs were analyzed which showed tofu dregs as waste with the highest rate of biodegradability compared to others since the tofu dregs do not contain any inhibitor which is lignin, have 2.7%VS, 14 C/N ratios and 97.3% organic matter. The highest cumulative methane production known as Biochemical Methane Potential was achieved by tofu dregs with volume of 77 ml during 30-day experiment which then followed by cow rumen, goat farm waste, and traditional market waste. Subsequently, methane productions were calculated through percentage of COD reduction, which showed the efficiency of 99.1% that indicates complete conversion of the high organic matter into methane.

  12. Anaerobic depuration of waste waters; Depuracion anaerobia de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Mejias Sanchez, G.; Vazquez Berger, E.; Magana Pietra, A.H. [Facultad de Ingenieria, Universidad Autonoma de yucatan, Merida (Mexico)

    1996-08-01

    Trials were carried out at a 500 l semi-experimental plant using there reactor models-anaerobic filter, fixed film and UASB type-for the anaerobic treatment of waste from different sources. The results after 24 and 48 hours were compared. The greatest efficiency was obtained after 48 hours the aerobic filter reactor (66% displacement), followed by the fixed film reactor (50%) and the UASB model (41%). (Author) 16 refs.

  13. Enhancement of waste activated sludge (WAS) anaerobic digestion by means of pre- and intermediate treatments. Technical and economic analysis at a full-scale WWTP.

    Science.gov (United States)

    Campo, Giuseppe; Cerutti, Alberto; Zanetti, Mariachiara; Scibilia, Gerardo; Lorenzi, Eugenio; Ruffino, Barbara

    2017-05-16

    Anaerobic digestion (AD) is the most commonly applied end-treatment for the excess of waste activated sludge (WAS) generated in biological wastewater treatment processes. The efficacy of different typologies of pre-treatments in liberating intra-cellular organic substances and make them more usable for AD was demonstrated in several studies. However, the production of new extracellular polymeric substances (EPSs) that occur during an AD process, due to microbial metabolism, self-protective reactions and cell lysis, partially neutralizes the benefit of pre-treatments. The efficacy of post- and inter-stage treatments is currently under consideration to overcome the problems due to this unavoidable byproduct. This work compares three scenarios in which low-temperature (WWTP, 2,000,000 p.e.). It was demonstrated that the introduction of thermal or hybrid pre-treatments could increase the revenues from the electricity sale by between 13% and 25%, in comparison with the present scenario (no lysis treatments). Conversely, intermediate treatments on a 7-day digestate could provide a gain of 26% or 32%, depending on the process temperature (70 or 90 °C). Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. [Agroindustrial wastes methanization and bacterial composition in anaerobic digestion].

    Science.gov (United States)

    González-Sánchez, María E; Pérez-Fabiel, Sergio; Wong-Villarreal, Arnoldo; Bello-Mendoza, Ricardo; Yañez-Ocampo, Gustavo

    2015-01-01

    The tons of organic waste that are annually generated by agro-industry, can be used as raw material for methane production. For this reason, it is important to previously perform biodegradability tests to organic wastes for their full scale methanization. This paper addresses biodegradability, methane production and the behavior of populations of eubacteria and archaeabacteria during anaerobic digestion of banana, mango and papaya agroindustrial wastes. Mango and banana wastes had higher organic matter content than papaya in terms of their volatile solids and total solid rate (94 and 75% respectively). After 63 days of treatment, the highest methane production was observed in banana waste anaerobic digestion: 63.89ml CH4/per gram of chemical oxygen demand of the waste. In the PCR-DGGE molecular analysis, different genomic footprints with oligonucleotides for eubacteria and archeobacteria were found. Biochemical methane potential results proved that banana wastes have the best potential to be used as raw material for methane production. The result of a PCR- DGGE analysis using specific oligonucleotides enabled to identify the behavior of populations of eubacteria and archaeabacteria present during the anaerobic digestion of agroindustrial wastes throughout the process. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Anaerobic bioleaching of metals from waste activated sludge

    KAUST Repository

    Meulepas, Roel J W

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

  16. Anaerobic digestion of municipal solid waste: Technical developments

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States)

    1996-01-01

    The anaerobic biogasification of organic wastes generates two useful products: a medium-Btu fuel gas and a compost-quality organic residue. Although commercial-scale digestion systems are used to treat municipal sewage wastes, the disposal of solid organic wastes, including municipal solid wastes (MSW), requires a more cost-efficient process. Modern biogasification systems employ high-rate, high-solids fermentation methods to improve process efficiency and reduce capital costs. The design criteria and development stages are discussed. These systems are also compared with conventional low-solids fermentation technology.

  17. Anaerobic bioleaching of metals from waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Meulepas, Roel J.W., E-mail: roel.meulepas@wetsus.nl [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Gonzalez-Gil, Graciela [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Teshager, Fitfety Melese; Witharana, Ayoma [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Saikaly, Pascal E. [King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands)

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g{sup −1} of copper, 487 μg g{sup −1} of lead, 793 μg g{sup −1} of zinc, 27 μg g{sup −1} of nickel and 2.3 μg g{sup −1} of cadmium. During the anaerobic acidification of 3 g{sub dry} {sub weight} L{sup −1} waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner.

  18. Anaerobic digestion of solid wastes of cane sugar industry

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, A.

    1983-01-01

    The cane sugar manufacturing industry generates large quantities of lignocellulosic solid wastes, namely bagasse and cachaza. Bagasse is the fibrous residue of the cane after extracting the juice. Cachaza is the filter cake of the precipitated insoluble sugars. This research investigates the feasibility of anaerobic digestion of a mixture of bagasse and cachaza to produce methane. Two rations of bagasse-cachaza mix as substrates were investigated. The first one was 8:1 which represents the average ratio of bagasse and cachaza produced in a raw sugar mill. The second ratio investigated was 2.4:1 which represents the proportion of bagasse and cachaza wastes after 70% of the bagasse is burned in sugar mill boilers. An acclimated microbial culture for this substrate was developed. Organic Loading-Detention Time relationships were established for an optimum system. Pre-treatment techniques of the substrate were investigated as a means of enhancing the digestibility of the cellulosic substrate. Recirculation of the filtrate was evaluated as a method for increasing solids retention time without increasing hydraulic detention time. The kinetics of the digestion process for bagasse-cachaza mixed substrate was investigated and growth constants were determined. The bionutritional characteristics of the substrate used for the digestion were evaluated. Based on the results obtained, mass balances and preliminary economic analysis of the digestion system were developed.

  19. The degradability of biodegradable plastics in aerobic and anaerobic waste landfill model reactors.

    Science.gov (United States)

    Ishigaki, Tomonori; Sugano, Wataru; Nakanishi, Akane; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori

    2004-01-01

    Degradabilities of four kinds of commercial biodegradable plastics (BPs), polyhydroxybutyrate and hydroxyvalerate (PHBV) plastic, polycaprolactone plastic (PCL), blend of starch and polyvinyl alcohol (SPVA) plastic and cellulose acetate (CA) plastic were investigated in waste landfill model reactors that were operated as anaerobically and aerobically. The application of forced aeration to the landfill reactor for supplying aerobic condition could potentially stimulate polymer-degrading microorganisms. However, the individual degradation behavior of BPs under the aerobic condition was completely different. PCL, a chemically synthesized BP, showed film breakage under the both conditions, which may have contributed to a reduction in the waste volume regardless of aerobic or anaerobic conditions. Effective degradation of PHBV plastic was observed in the aerobic condition, though insufficient degradation was observed in the anaerobic condition. But the aeration did not contribute much to accelerate the volume reduction of SPVA plastic and CA plastic. It could be said that the recalcitrant portions of the plastics such as polyvinyl alcohol in SPVA plastic and the highly substituted CA in CA plastic prevented the BP from degradation. These results indicated existence of the great variations in the degradability of BPs in aerobic and anaerobic waste landfills, and suggest that suitable technologies for managing the waste landfill must be combined with utilization of BPs in order to enhance the reduction of waste volume in landfill sites.

  20. Animal and industrial waste anaerobic digestion: USA status report

    Energy Technology Data Exchange (ETDEWEB)

    Lusk, P.D. [Resource Development Associates, Washington, DC (United States)

    1996-01-01

    Pollutants from unmanaged animal and bio-based industrial wastes can degrade the environment, and methane emitted from decomposing wastes may contribute to global climate change. One waste management system prevents pollution and converts a disposal problem into a new profit center. Case studies of operating systems indicate that the anaerobic digestion of animal and industrial wastes is a commercially available bioconversion technology with considerable potential for providing profitable coproducts, including a cost-effective renewable fuel. Growth and concentration of the livestock industry create opportunities to properly dispose of the large quantities of manures generated at dairy, swine, and poultry farms. Beyond the farm, extension of the anaerobic digestion process to recover methane has considerable potential for certain classified industries - with a waste stream characterization similar to livestock manures. More than 35 example industries have been identified, and include processors of chemicals, fiber, food, meat, milk, and pharmaceuticals. Some of these industries already recover methane for energy. This status report examines some current opportunities for recovering methane from the anaerobic digestion of animal and industrial wastes in the US. Case studies of operating digesters, including project and maintenance histories, and the operator`s {open_quotes}lessons learned,{close_quotes} are included as a reality check. Factors necessary for successful projects, as well as a list of reasons explaining why some anaerobic digestion projects fail, are provided. The role of management is key; not only must digesters be well engineered and built with high-quality components, they must also be sited at facilities willing to incorporate the uncertainties of a new technology. Anaerobic digestion can provide monetary benefits and mitigate possible pollution problems, thereby sustaining development while maintaining environmental quality.

  1. Anaerobic digestion of tannery waste: semi-continuous and anaerobic sequencing batch reactor processes.

    Science.gov (United States)

    Zupancic, Gregor D; Jemec, A

    2010-01-01

    Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37 degrees C or 55 degrees C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100 days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55 degrees C is estimated to be 0.617 m(3)kg(-1) of volatile suspended solids for tannery waste sludge, 0.377 m(3)kg(-1) for tannery waste trimmings and 0.649 m(3)kg(-1) for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4 degrees C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55 degrees C.

  2. Continuous biohydrogen production from waste bread by anaerobic sludge.

    Science.gov (United States)

    Han, Wei; Huang, Jingang; Zhao, Hongting; Li, Yongfeng

    2016-07-01

    In this study, continuous biohydrogen production from waste bread by anaerobic sludge was performed. The waste bread was first hydrolyzed by the crude enzymes which were generated by Aspergillus awamori and Aspergillus oryzae via solid-state fermentation. It was observed that 49.78g/L glucose and 284.12mg/L free amino nitrogen could be produced with waste bread mass ratio of 15% (w/v). The waste bread hydrolysate was then used for biohydrogen production by anaerobic sludge in a continuous stirred tank reactor (CSTR). The optimal hydrogen production rate of 7.4L/(Ld) was achieved at chemical oxygen demand (COD) of 6000mg/L. According to the results obtained from this study, 1g waste bread could generate 0.332g glucose which could be further utilized to produce 109.5mL hydrogen. This is the first study which reports continuous biohydrogen production from waste bread by anaerobic sludge.

  3. Influence of fluid dynamics on anaerobic digestion of food waste for biogas production.

    Science.gov (United States)

    Wang, Fengping; Zhang, Cunsheng; Huo, Shuhao

    2016-08-17

    To enhance the stability and efficiency of an anaerobic process, the influences of fluid dynamics on the performance of anaerobic digestion and sludge granulation were investigated using computational fluid dynamics (CFD). Four different propeller speeds (20, 60, 100, 140 r/min) were adopted for anaerobic digestion of food waste in a 30 L continuously stirred tank reactor (CSTR). Experimental results indicated that the methane yield increased with increasing the propeller speed within the experimental range. Results from CFD simulation and sludge granulation showed that the optimum propeller speed for anaerobic digestion was 100 r/min. Lower propeller speed (20 r/min) inhibited mass transfer and resulted in the failure of anaerobic digestion, while higher propeller speed (140 r/min) would lead to higher energy loss and system instability. Under this condition, anaerobic digestion could work effectively with higher efficiency of mass transfer which facilitated sludge granulation and biogas production. The corresponding mean liquid velocity and shear strain rate were 0.082 m/s and 10.48 s(-1), respectively. Moreover, compact granular sludge could be formed, with lower energy consumption. CFD was successfully used to study the influence of fluid dynamics on the anaerobic digestion process. The key parameters of the optimum mixing condition for anaerobic digestion of food waste in a 30 L CSTR including liquid velocity and shear strain rate were obtained using CFD, which were of paramount significance for the scale-up of the bioreactor. This study provided a new way for the optimization and scale-up of the anaerobic digestion process in CSTR based on the fluid dynamics analysis.

  4. Anaerobic co-digestion of animal waste: swine manure and tuna fish waste

    Energy Technology Data Exchange (ETDEWEB)

    Otero, L.; Alvarez, J. A.; Lema, J. M.

    2009-07-01

    Anaerobic digestion has become an established and proven technology for the treatment of solid wastes. Co-digestion offers several possible ecological, technology and economical advantages. Anaerobic co-digestion can increase CH{sub 4} production of manure diesters in a 50-200% according to the operation conditions and the co-substrates used. Last September 2007, PROBIOGAS project started up with the objective of improving the production and use of biogas from co-digestion of farming, agricultural and industrial waste. Our research group takes part in the study of co-digestion of swine manure firstly with tuna fish waste and secondly with glycerine (bio diesel production waste). (Author)

  5. Treatment of urban residential organic waste through anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Fabiane Granzotto

    2016-10-01

    Full Text Available The amount of waste generated nowadays is a reflection of population growth and consumerism, many times, unnecessary by people. Organic waste is the most part of the solid waste generated. This waste need to be treated adequately to avoid environmental problems and health problems in people. The objective was to treat urban residential organic waste and to verify the efficiency of the transformation into biogas and bio fertilizers. A digester of the Indian type was used in Nova Palma, Rio Grande do Sul. The research was developed in the period of three years with a daily monitoring. The average biogas production was higher in the summer for three years and it was more stable in the third year in different seasons. There were no reagents to coliforms. The study found that anaerobic digestion has potential in treating organic waste.

  6. [Effect of moisture content on anaerobic methanization of municipal solid waste].

    Science.gov (United States)

    Qu, Xian; He, Pin-Jing; Shao, Li-Ming; Bouchez, Théodore

    2009-03-15

    Biogas production, gas and liquid characteristics were investigated for comparing the effect of moisture content on methanization process of MSW with different compositions of food waste and cellulosic waste. Batch reactors were used to study the anaerobic methanization of typical Chinese and French municipal solid waste (MSW) and cellulosic waste with different moisture content, as 35%, field capacity (65%-70%), 80%, and saturated state (> 95%). The results showed that for the typical Chinese and French waste, which contained putrescible waste, the intermediate product, VFA, was diluted by high content of water, which helped to release the VFA inhibition on hydrolysis and methanization. Mass amount of methane was produced only when the moisture content of typical French waste was higher than 80%, while higher content of moisture was needed when the content of putrescible waste was higher in MSW, as > 95% for typical Chinese waste. Meanwhile the methane production rate and the ultimate cumulated methane production were increased when moisture content was leveled up. The ultimate cumulated methane production of the typical French waste with saturated state was 0.6 times higher than that of the waste with moisture content of 80%. For cellulosic waste, high moisture content of cellulosic materials contributed to increase the attachment area of microbes and enzyme on the surface of the materials, which enhance the waste hydrolysis and methanization. When the moisture content of the cellulosic materials increased from field capacity (65%) to saturated state (> 95%), the ultimate cumulated methane production increased for 3.8 times.

  7. Anaerobic treatment of lactic waste and goat manure

    Directory of Open Access Journals (Sweden)

    J. Luís Magaña-Ramírez

    2011-01-01

    Full Text Available Anaerobic digestion was carried out to obtain biogas from lactic waste in combination with goat manure. Waste from lactic products such as cream, cheese and whey was mixed with goat manure using three formulations; the quantity of waste from cream and cheese was maintained, and only the quantity of manure and whey was varied. Methanogenic bacteria obtained from predigestion of goat manure were used as inoculants. Temperature was 35ºC and pH 7.0.Biogas methane percentage was determined by gas chromatography. The results showed that the highest methane concentration obtained was 82% with formulation III.

  8. Digestion of frozen/thawed food waste in the hybrid anaerobic solid-liquid system.

    Science.gov (United States)

    Stabnikova, O; Liu, X Y; Wang, J Y

    2008-01-01

    The hybrid anaerobic solid-liquid (HASL) system, which is a modified two-phase anaerobic digester, is to be used in an industrial scale operation to minimize disposal of food waste at incineration plants in Singapore. The aim of the present research was to evaluate freezing/thawing of food waste as a pre-treatment for its anaerobic digestion in the HASL system. The hydrolytic and fermentation processes in the acidogenic reactor were enhanced when food waste was frozen for 24h at -20 degrees C and then thawed for 12h at 25 degrees C (experiment) in comparison with fresh food waste (control). The highest dissolved COD concentrations in the leachate from the acidogenic reactors were 16.9 g/l on day 3 in the control and 18.9 g/l on day 1 in the experiment. The highest VFA concentrations in the leachate from the acidogenic reactors were 11.7 g/l on day 3 in the control and 17.0 g/l on day 1 in the experiment. The same volume of methane was produced during 12 days in the control and 7 days in the experiment. It gave the opportunity to diminish operational time of batch process by 42%. The effect of freezing/thawing of food waste as pre-treatment for its anaerobic digestion in the HASL system was comparable with that of thermal pre-treatment of food waste at 150 degrees C for 1h. However, estimation of energy required either to heat the suspended food waste to 150 degrees C or to freeze the same quantity of food waste to -20 degrees C showed that freezing pre-treatment consumes about 3 times less energy than thermal pre-treatment.

  9. Anaerobic co-digestion of coffee waste and sewage sludge.

    Science.gov (United States)

    Neves, L; Oliveira, R; Alves, M M

    2006-01-01

    The feasibility of the anaerobic co-digestion of coffee solid waste and sewage sludge was assessed. Five different solid wastes with different chemical properties were studied in mesophilic batch assays, providing basic data on the methane production, reduction of total and volatile solids and hydrolysis rate constant. Most of the wastes had a methane yield of 0.24-0.28 m3 CH4(STP)/kg VS(initial) and 76-89% of the theoretical methane yield was achieved. Reduction of 50-73% in total solids and 75-80% in volatile solids were obtained and the hydrolysis rate constants were in the range of 0.035-0.063 d(-1). One of the solid wastes, composed of 100% barley, achieved a methane yield of 0.02 m3 CH4(STP)/kg VS(initial), reductions of 31% in total solids, 40% in volatile solids and achieved only 11% of the theoretical methane yield. However, this waste presented the highest hydrolysis rate constant. Considering all the wastes, an inverse linear correlation was obtained between methane yield and the hydrolysis rate constant, suggesting that hydrolysis was not the limiting factor in the anaerobic biodegradability of this type of waste.

  10. Methane production during storage of anaerobically digested municipal organic waste.

    Science.gov (United States)

    Hansen, Trine Lund; Sommer, Svend G; Gabriel, Søren; Christensen, Thomas H

    2006-01-01

    Anaerobic digestion of source-separated municipal organic waste is considered feasible in Denmark. The limited hydraulic retention in the biogas reactor (typically 15 d) does not allow full degradation of the organic waste. Storage of anaerobically digested municipal organic waste can therefore be a source of methane (CH4) emission that may contribute significantly to the potential global warming impact from the waste treatment system. This study provides a model for quantifying the CH4 production from stored co-digested municipal organic waste and estimates the production under typical Danish climatic conditions, thus quantifying the potential global warming impact from storage of the digested municipal organic waste before its use on agricultural land. Laboratory batch tests on CH4 production as well as temperature measurements in eight full-scale storage tanks provided data for developing a model estimating the CH4 production in storage tanks containing digested municipal organic waste. The temperatures measured in separate storage tanks on farms receiving digested slurry were linearly correlated with air temperature. In storage tanks receiving slurry directly from biogas reactors, significantly higher temperatures were measured due to the high temperatures of the effluent from the reactor. Storage tanks on Danish farms are typically emptied in April and have a constant inflow of digested material. During the warmest months the content of digested material is therefore low, which limits the yearly CH4 production from storage.

  11. Importance of storage time in mesophilic anaerobic digestion of food waste.

    Science.gov (United States)

    Lü, Fan; Xu, Xian; Shao, Liming; He, Pinjing

    2016-07-01

    Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1, 2, 3, 4, 5, 7, and 12days, and then fed into a methanogenic reactor for a biochemical methane potential (BMP) test lasting up to 60days. Relative to the methane production of food waste stored for 0-1day (285-308mL/g-added volatile solids (VSadded)), that after 2-4days and after 5-12days of storage increased to 418-530 and 618-696mL/g-VSadded, respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5-7days of storage of food waste in anaerobic digestion treatment plants. Copyright © 2016. Published by Elsevier B.V.

  12. Anaerobic co-digestion of sewage sludge and food waste.

    Science.gov (United States)

    Prabhu, Meghanath S; Mutnuri, Srikanth

    2016-04-01

    Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion.

  13. Hydrogen generation via anaerobic fermentation of paper mill wastes.

    Science.gov (United States)

    Valdez-Vazquez, Idania; Sparling, Richard; Risbey, Derek; Rinderknecht-Seijas, Noemi; Poggi-Varaldo, Héctor M

    2005-11-01

    The objective of this work was to determine the hydrogen production from paper mill wastes using microbial consortia of solid substrate anaerobic digesters. Inocula from mesophilic, continuous solid substrate anaerobic digestion (SSAD) reactors were transferred to small lab scale, batch reactors. Milled paper (used as a surrogate paper waste) was added as substrate and acetylene or 2-bromoethanesulfonate (BES) was spiked for methanogenesis inhibition. In the first phase of experiments it was found that acetylene at 1% v/v in the headspace was as effective as BES in inhibiting methanogenic activity. Hydrogen gas accumulated in the headspace of the bottles, reaching a plateau. Similar final hydrogen concentrations were obtained for reactors spiked with acetylene and BES. In the second phase of tests the headspace of the batch reactors was flushed with nitrogen gas after the first plateau of hydrogen was reached, and subsequently incubated, with no further addition of inhibitor nor substrate. It was found that hydrogen production resumed and reached a second plateau, although somewhat lower than the first one. This procedure was repeated a third time and an additional amount of hydrogen was obtained. The plateaux and initial rates of hydrogen accumulation decreased in each subsequent incubation cycle. The total cumulative hydrogen harvested in the three cycles was much higher (approx. double) than in the first cycle alone. We coined this procedure as IV-SSAH (intermittently vented solid substrate anaerobic hydrogen generation). Our results point out to a feasible strategy for obtaining higher hydrogen yields from the fermentation of industrial solid wastes, and a possible combination of waste treatment processes consisting of a first stage IV-SSAH followed by a second SSAD stage. Useful products of this approach would be hydrogen, organic acids or methane, and anaerobic digestates that could be used as soil amenders after post-treatment.

  14. Hydrogen generation via anaerobic fermentation of paper mill wastes

    Energy Technology Data Exchange (ETDEWEB)

    Valdez Vazquez, I.; Poggi Varaldo, H.M. [CINVESTAV-IPN, Mexico D.F. (Mexico). Dept. of Biotechnology and Bioengineering; Sparling, R.; Risbey, D. [Manitoba Univ., Winnipeg (Canada). Dept. of Microbiology; Rinderknecht Seijas, N. [ESIQUIE-IPN, Mexico D.F. (Mexico). Division Base Sciences

    2005-11-15

    The objective of this work was to determine the hydrogen production from paper mill wastes using microbial consortia of solid substrate anaerobic digesters. Inocula from mesophilic, continuous solid substrate anaerobic digestion (SSAD) reactors were transferred to small lab scale, batch reactors. Milled paper (used as a surrogate paper waste) was added as substrate and acetylene or 2-bromoethanesulfonate (BES) was spiked for methanogenesis inhibition. In the first phase of experiments it was found that acetylene at 1% v/v in the headspace was as effective as BES in inhibiting methanogenic activity. Hydrogen gas accumulated in the headspace of the bottles, reaching a plateau. Similar final hydrogen concentrations were obtained for reactors spiked with acetylene and BES. In the second phase of tests the headspace of the batch reactors was flushed with nitrogen gas after the first plateau of hydrogen was reached, and subsequently incubated, with no further addition of inhibitor nor substrate. It was found that hydrogen production resumed and reached a second plateau, although somewhat lower than the first one. This procedure was repeated a third time and an additional amount of hydrogen was obtained. The plateaux and initial rates of hydrogen accumulation decreased in each subsequent incubation cycle. The total cumulative hydrogen harvested in the three cycles was much higher (approx. double) than in the first cycle alone. We coined this procedure as IV-SSAH (intermittently vented solid substrate anaerobic hydrogen generation). Our results point out to a feasible strategy for obtaining higher hydrogen yields from the fermentation of industrial solid wastes, and a possible combination of waste treatment processes consisting of a first stage IV-SSAH followed by a second SSAD stage. Useful products of this approach would be hydrogen, organic acids or methane, and anaerobic digestates that could be used as soil amenders after post-treatment. (author)

  15. Electrolysis-enhanced anaerobic digestion of wastewater.

    Science.gov (United States)

    Tartakovsky, B; Mehta, P; Bourque, J-S; Guiot, S R

    2011-05-01

    This study demonstrates enhanced methane production from wastewater in laboratory-scale anaerobic reactors equipped with electrodes for water electrolysis. The electrodes were installed in the reactor sludge bed and a voltage of 2.8-3.5 V was applied resulting in a continuous supply of oxygen and hydrogen. The oxygen created micro-aerobic conditions, which facilitated hydrolysis of synthetic wastewater and reduced the release of hydrogen sulfide to the biogas. A portion of the hydrogen produced electrolytically escaped to the biogas improving its combustion properties, while another part was converted to methane by hydrogenotrophic methanogens, increasing the net methane production. The presence of oxygen in the biogas was minimized by limiting the applied voltage. At a volumetric energy consumption of 0.2-0.3 Wh/L(R), successful treatment of both low and high strength synthetic wastewaters was demonstrated. Methane production was increased by 10-25% and reactor stability was improved in comparison to a conventional anaerobic reactor.

  16. Anaerobic digestion and co-digestion of slaughterhouse wastes

    Directory of Open Access Journals (Sweden)

    Sonia Castellucci

    2013-09-01

    Full Text Available The use of renewable energy is becoming increasingly necessary in order to address the global warming problem and, as a consequence, has become an high priority for many countries. Biomass is a clean and renewable energy source with growing potential to replace conventional fossil fuels. Among biomass, residual and waste ones represent a great resource for energy generation since they permit both to eliminate a possible waste and to produce energy. In the present work, the case of slaughterhouse wastes (SHWs has been investigated. Anaerobic digestion is nowadays considered as one of the most important and sustainable conversion technology exploiting organic matter and biodegradable wastes. Biogas results from this bio-chemical process and mainly consists of methane and carbon dioxide, leading to produce thermal energy and/or electricity. In this paper, the European Regulations on animal by-products (ABPs are described, and some previous study on anaerobic digestion and co-digestion of ABPs - more precisely SHWs - are considered and compared in order to fix a starting point for future tests on their co-digestion in a micro-scale pilot digester. This is to define optimal feed ratio values which ensure an increasing content of methane in the outgoing biogas.

  17. Enhancement of anaerobic degradation of azo dye with riboflavin and nicotinamide adenine dinucleotide harvested by osmotic lysis of wasted fermentation yeasts.

    Science.gov (United States)

    Victral, Davi M; Dias, Heitor R A; Silva, Silvana Q; Baeta, Bruno E L; Aquino, Sérgio F

    2017-02-01

    The study presented here aims at identifying the source of redox mediators (riboflavin), electron carriers nicotinamide adenine dinucleotide (NAD) and carbon to perform decolorization of azo dye under anaerobic conditions after osmotic shock pretreatment of residual yeast from industrial fermentation. Pretreatment conditions were optimized by Doehlert experiment, varying NaCl concentration, temperature, yeast density and time. After the optimization, the riboflavin concentration in the residual yeast lysate (RYL) was 46% higher than the one present in commercial yeast extract. Moreover, similar NAD concentration was observed in both extracts. Subsequently, two decolorization experiments were performed, that is, a batch experiment (48 h) and a kinetic experiment (102 h). The results of the batch experiment showed that the use of the RYL produced by the optimized method increased decolorization rates and led to color removal efficiencies similar to those found when using the commercial extract (∼80%) and from 23% to 50% higher when compared to the control (without redox mediators). Kinetics analysis showed that methane production was also higher in the presence of yeast extract and RYL, and biogas was mostly generated after stabilization of color removal. In all kinetics experiments the azo dye degradation followed the pseudo-second-order model, which suggested that there was a concomitant adsorption/degradation of the dye on the biomass cell surface. Therefore, results showed the possibility of applying the pretreated residual yeast to improve color removal under anaerobic conditions, which is a sustainable process.

  18. Anaerobic co-digestion of dairy manure and potato waste

    Science.gov (United States)

    Yadanaparthi, Sai Krishna Reddy

    Dairy and potato are two important agricultural commodities in Idaho. Both the dairy and potato processing industries produce a huge amount of waste which could cause environmental pollution. To minimize the impact of potential pollution associated with dairy manure (DM) and potato waste (PW), anaerobic co-digestion has been considered as one of the best treatment process. The purpose of this research is to evaluate the anaerobic co-digestion of dairy manure and potato waste in terms of process stability, biogas generation, construction and operating costs, and potential revenue. For this purpose, I conducted 1) a literature review, 2) a lab study on anaerobic co-digestion of dairy manure and potato waste at three different temperature ranges (ambient (20-25°C), mesophilic (35-37°C) and thermophilic (55-57°C) with five mixing ratios (DM:PW-100:0, 90:10, 80:20, 60:40, 40:60), and 3) a financial analysis for anaerobic digesters based on assumed different capital costs and the results from the lab co-digestion study. The literature review indicates that several types of organic waste were co-digested with DM. Dairy manure is a suitable base matter for the co-digestion process in terms of digestion process stability and methane (CH4) production (Chapter 2). The lab tests showed that co-digestion of DM with PW was better than digestion of DM alone in terms of biogas and CH4 productions (Chapter 3). The financial analysis reveals DM and PW can be used as substrate for full size anaerobic digesters to generate positive cash flow within a ten year time period. Based on this research, the following conclusions and recommendations were made: ▸ The ratio of DM:PW-80:20 is recommended at thermophilic temperatures and the ratio of DM:PW-90:10 was recommended at mesophilic temperatures for optimum biogas and CH4 productions. ▸ In cases of anaerobic digesters operated with electricity generation equipment (generators), low cost plug flow digesters (capital cost of 600/cow

  19. Using feature objects aided strategy to evaluate the biomethane production of food waste and corn stalk anaerobic co-digestion.

    Science.gov (United States)

    Zhou, Qi; Yuan, Hairong; Liu, Yanping; Zou, Dexun; Zhu, Baoning; Chufo, Wachemo A; Jaffar, Muhammad; Li, Xiujin

    2015-03-01

    Feature objects aided strategy was used to predict and evaluate the biomethane production of food waste and corn stalk anaerobic co-digestion. The kinetics of co-digestion and mono-digestion of food waste and/or corn stalk was also analyzed. The results indicated that the compositions of food waste and corn stalk were significantly different. The anaerobic digestion of three feature objects at different mixing ratios showed the different biomethane yields and kinetic constants. Food waste and corn stalk co-digestion enhanced the digestion rate and achieved 22.48% and 41.55% higher biomethane production than those of food waste and corn stalk mono-digestion, respectively.

  20. Effect of nonylphenol on volatile fatty acids accumulation during anaerobic fermentation of waste activated sludge.

    Science.gov (United States)

    Duan, Xu; Wang, Xiao; Xie, Jing; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

    2016-11-15

    Most of the reported studies on anaerobic fermentation of sludge focused on the influences of operating conditions, pretreatment methods, and its characteristics, and little attention was paid to those of persistent organic pollutants (POPs) which widespreadly appeared in sludge. In this study, the effect of nonylphenol, a typical POPs in waste activated sludge (WAS), on anaerobic fermentation for volatile fatty acids (VFAs) accumulation was investigated. The concentration of VFAs during WAS anaerobic fermentation was found to be affected positively from 2856 mg COD/L in the control (without NP) to 5620 mg COD/L with NP of 200 mg/kg dry sludge. Mechanism exploration exhibited that the main reason for the enhanced VFAs accumulation in the presence of NP was that more acetic acid was generated during the acidification of WAS, which was increased by almost three times (3790 versus 1310 mg COD/L). In WAS fermentation systems, the abundance of anaerobic functional microorganisms was advantageous to the accumulation of acetic acid. Further investigation by the pure acetogen revealed that both the viability and activity of Proteiniphilum acetatigenes were improved by NP during anaerobic fermentation, resulting in more production of acetic acid and showing good agreement with that in the real WAS fermentation systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

    Science.gov (United States)

    Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

    2015-12-01

    This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively.

  2. Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Suschka Jan

    2014-07-01

    Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

  3. Anaerobic digestion of yard waste with hydrothermal pretreatment.

    Science.gov (United States)

    Li, Wangliang; Zhang, Guangyi; Zhang, Zhikai; Xu, Guangwen

    2014-03-01

    The digestibility of lignocellulosic biomass is limited by its high content of refractory components. The objective of this study is to investigate hydrothermal pretreatment and its effects on anaerobic digestion of sorted organic waste with submerged fermentation. Hydrothermal pretreatment (HT) was performed prior to anaerobic digestion, and three agents were examined for the HT: hot compressed water, alkaline solution, and acidic solution. The concentrations of glucose and xylose were the highest in the sample pretreated in acidic solution. Compared with that of the untreated sample, the biogas yields from digesting the samples pretreated in alkaline solution, acidic solution, and hot water increased by 364, 107, and 79%, respectively. The decrease of chemical oxygen demand (COD) in liquid phase followed the same order as for the biogas yield. The initial ammonia content of the treated samples followed the order sample treated in acidic solution > sample treated in alkaline solution > sample treated in hot water. The concentrations of volatile fatty acids (VFAs) were low, indicating that the anaerobic digestion process was running at continuously stable conditions.

  4. Biogas by semi-continuous anaerobic digestion of food waste.

    Science.gov (United States)

    Zhang, Cunsheng; Su, Haijia; Wang, Zhenbin; Tan, Tianwei; Qin, Peiyong

    2015-04-01

    The semi-continuous anaerobic digestion of food waste was investigated in 1-L and 20-L continuously stirred tank reactors (CSTRs), to identify the optimum operation condition and the methane production of the semi-continuous anaerobic process. Results from a 1-L digester indicated that the optimum organic loading rate (OLR) for semi-continuous digestion is 8 g VS/L/day. The corresponding methane yield and chemical oxygen demand (COD) reduction were 385 mL/g VS and 80.2 %, respectively. Anaerobic digestion was inhibited at high OLRs (12 and 16 g VS/L/day), due to volatile fatty acid (VFA) accumulation. Results from a 20-L digester indicated that a higher methane yield of 423 mL/g VS was obtained at this larger scale. The analysis showed that the methane production at the optimum OLR fitted well with the determined kinetics equation. An obvious decrease on the methane content was observed at the initial of digestion. The increased metabolization of microbes and the activity decrease of methanogen caused by VFA accumulation explained the lower methane content at the initial of digestion.

  5. Dry anaerobic digestion of the organic fraction of municipal solid waste

    NARCIS (Netherlands)

    Brummeler, ten E.

    1993-01-01

    Anaerobic digestion is an attractive technology for solid waste management. This thesis describes the technological potentials of dry anaerobic digestion of the organic fraction of Municipal Solid Waste (MSW) using batch systems. In 1985 a research programme was started to develop the so- c

  6. Dry anaerobic digestion of the organic fraction of municipal solid waste.

    NARCIS (Netherlands)

    ten Brummeler, E.

    1993-01-01

    Anaerobic digestion is an attractive technology for solid waste management. This thesis describes the technological potentials of dry anaerobic digestion of the organic fraction of Municipal Solid Waste (MSW) using batch systems. In 1985 a research programme was started to develop the so- called BIO

  7. Dry anaerobic digestion of the organic fraction of municipal solid waste

    NARCIS (Netherlands)

    Brummeler, ten E.

    1993-01-01

    Anaerobic digestion is an attractive technology for solid waste management. This thesis describes the technological potentials of dry anaerobic digestion of the organic fraction of Municipal Solid Waste (MSW) using batch systems. In 1985 a research programme was started to develop the so-

  8. Technology of Enhanced Anaerobic Digestion Processes with Zero-Valent Iron for Treatment of Solid Waste Landfill Leachate%垃圾渗滤液的零价铁强化厌氧处理技术

    Institute of Scientific and Technical Information of China (English)

    张鑫; 朱南文; 楼紫阳; 袁海平; 王艳

    2013-01-01

    该文采用零价铁强化中转站垃圾渗滤液的厌氧处理方法,考察了进水浓度、初始pH和铁投加量对渗滤渡污染物的去除效果,并探讨了零价铁强化厌氧处理机理.结果表明零价铁的投加可有效强化渗滤液的厌氧处理效果,在进水浓度为22656 mg/L、初始pH为7.0、铁投加量为600 mg/L的最佳条件下,经过50 d厌氧处理,出水COcr降低至7800 mg/L,COD去除率为65.1%.而未投加铁的体系出水CODcr为11560 mg/L,COD去除率为48.2%.%Leachate from waste transfer station was treated by Fe0 enhanced anaerobic treatment in this paper.Effect of influent concentration,initial pH and Fe0 dosage on COD removal efficiency was investigated.The results show that leachate effluent CODcr can attain 7800 mg/L and COD removal rate is 65.1% after 50 days' reaction under the optimum operation conditions,when the influent CODcr is 22 656 mg/L,initial pH is 7.0 and Fe0 dosage is 600 mg/L.While effluent CODcr is around 11 560 mg/L and COD removal rate is 48.2 % without Fe0 dosage.

  9. Biogas energy production from tropical biomass wastes by anaerobic digestion.

    Science.gov (United States)

    Ge, Xumeng; Matsumoto, Tracie; Keith, Lisa; Li, Yebo

    2014-10-01

    Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass and food wastes, such as taro, papaya, and sweet potato, are limited. In this study, these tropical biomass wastes were evaluated for biogas production by liquid AD (L-AD) and/or solid-state AD (SS-AD), depending on feedstock characteristics. When albizia leaves and chips were used as feedstocks, L-AD had greater methane yields (161 and 113 L kg(-1)VS, respectively) than SS-AD (156.8 and 59.6 L kg(-1)VS, respectively), while SS-AD achieved 5-fold higher volumetric methane productivity than L-AD. Mono-digestion and co-digestion of taro skin, taro flesh, papaya, and sweet potato achieved methane yields from 345 to 411 L kg(-1)VS, indicating the robustness of AD technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Biological nutrients removal from the supernatant originating from the anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Malamis, S; Katsou, E; Di Fabio, S; Bolzonella, D; Fatone, F

    2014-09-01

    This study critically evaluates the biological processes and techniques applied to remove nitrogen and phosphorus from the anaerobic supernatant produced from the treatment of the organic fraction of municipal solid waste (OFMSW) and from its co-digestion with other biodegradable organic waste (BOW) streams. The wide application of anaerobic digestion for the treatment of several organic waste streams results in the production of high quantities of anaerobic effluents. Such effluents are characterized by high nutrient content, because organic and particulate nitrogen and phosphorus are hydrolyzed in the anaerobic digestion process. Consequently, adequate post-treatment is required in order to comply with the existing land application and discharge legislation in the European Union countries. This may include physicochemical and biological processes, with the latter being more advantageous due to their lower cost. Nitrogen removal is accomplished through the conventional nitrification/denitrification, nitritation/denitritation and the complete autotrophic nitrogen removal process; the latter is accomplished by nitritation coupled with the anoxic ammonium oxidation process. As anaerobic digestion effluents are characterized by low COD/TKN ratio, conventional denitrification/nitrification is not an attractive option; short-cut nitrogen removal processes are more promising. Both suspended and attached growth processes have been employed to treat the anaerobic supernatant. Specifically, the sequencing batch reactor, the membrane bioreactor, the conventional activated sludge and the moving bed biofilm reactor processes have been investigated. Physicochemical phosphorus removal via struvite precipitation has been extensively examined. Enhanced biological phosphorus removal from the anaerobic supernatant can take place through the sequencing anaerobic/aerobic process. More recently, denitrifying phosphorus removal via nitrite or nitrate has been explored. The removal of

  11. [Pilot study of thermal treatment/thermophilic anaerobic digestion process treating waste activated sludge of high solid content].

    Science.gov (United States)

    Wu, Jing; Wang, Guang-qi; Cao, Zhi-ping; Li, Zhong-hua; Hu, Yu-ying; Wang, Kai-jun; Zu, Jian-e

    2014-09-01

    A pilot-scale experiment about the process of "thermal pretreatment at 70°C/thermophilic anaerobic digestion" of waste activated sludge of high solid content (8% -9% ) was conducted. The process employed thermal treatment of 3 days to accelerate the hydrolysis and thermophilic digestion to enhance anaerobic reaction. Thus it was good at organic removal and stabilization. When the solid retention time (SRT) was longer than 20 days, the VSS removal rate was greater than 42. 22% and it was linearly correlated to the SRT of the aerobic digestion with the R2 of 0. 915 3. It was suggested that SRT of anaerobic digestion was 25 days in practice. VSS removal rate and biogas production rate of the pilot experiment were similar to those of the run-well traditional full-scale sludge anaerobic digestion plants (solid content 3% -5% ) and the plant of high solid content using German technique.

  12. Influence of thermal pretreatment on physical and chemical properties of kitchen waste and the efficiency of anaerobic digestion.

    Science.gov (United States)

    Jin, Yiying; Li, Yangyang; Li, Jinhui

    2016-09-15

    The effects of thermal pretreatment at moderate temperatures (70, 80 and 90 °C) and high temperatures (120, 140 and 160 °C) over heating durations of 10-120 min on the physical and chemical properties of kitchen waste and on anaerobic digestion were investigated. The results show that thermal pretreatment significantly enhances the solubilisation of organic compounds (chemical oxygen demand, crude proteins, crude fats and volatile fatty acids) and their biodegradability during subsequent anaerobic digestion. High temperature and long heating duration are beneficial for the release and reduction of organic compounds, and the efficiency of subsequent anaerobic digestion is improved markedly under these conditions. Moreover, both the methane production rate and methane yield were observed to increase significantly at moderate treatment temperatures when the anaerobic digestion time was longer than 50 h.

  13. Anaerobic digestion of municipal solid waste as a treatment prior to landfill

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, P.H.L.; Kuruparan, P.; Visvanathan, C. [Asian Institute of Technology, Pathumthani (Thailand). Environmental Engineering and Management Program

    2007-02-15

    Anaerobic digestion of organic fraction of municipal solid waste was conducted in pilot-scale reactor based on high-solid combined anaerobic digestion process. This study was performed in two runs. In Run1 and Run 2, pre-stage flushing and micro-aeration were conducted to determine their effect in terms of enhancing hydrolysis and acidification in ambient condition. In Run 2, after pre-stage, the methane phase (methanogenesis) was started-up after pH adjustment and inoculum addition in mesophilic condition. Acidified leachate produced in pre-stage was used for percolation during active methane phase. At the end of methane phase, air flushing was conducted before unloading the digesters. Hydrolysis an acidification yield of 140 g C/kg TS and 180 g VFA/kg TS were achieved, respectively in pre-stage. Micro-aeration exhibited an equivocal result in terms of enhancing hydrolysis/acidification; however it showed a positive effect in methane phase performance and this needed further investigation. Leachate percolation during methane phase showed an enhanced methanization when compared to the reactors without leachate percolation. After 60 days, 260 l CH{sub 4}/kg VS was obtained. Based on the waste methane potential, 75% biogas conversion and 61% VS degradation were achieved. (author)

  14. ASSESSMENT OF WASTE TREATMENT AND ENERGY RECOVERY FROM DAIRY INDUSTRIAL WASTE BY ANAEROBIC DIGESTION

    Directory of Open Access Journals (Sweden)

    Richa Kothari, Virendra Kumar, and Vineet Veer Tyagi

    2011-01-01

    Full Text Available Waste treatment with simultaneous energy generation was studied in anaerobic digester using dairy industry waste (sludge, influent as substrate. No pretreatment or solid liquid separation was applied. Batch fermentation experiments were performed with three different substrates at organic pollution load (OPL under mesophilic range of temperature (30_+C. Experimental data evidence the effectiveness of waste on both the removal efficiency in terms of substrate degradation and biogas yield, particularly at higher loading rates. Among the three substrates evaluated, alternative substrates showed comparatively effective performance in comparison to conventional one. However, COD removal efficiency was also found to be effective in operated environment. The described process provides the dual benefit of waste treatment with simultaneous green energy generation in the form of biogas utilizing it as substrate.

  15. Anaerobic treatment of waste waters from soybean protein production. Anaerobe Aufbereitung von Abwaessern aus der Sojaproteinherstellung

    Energy Technology Data Exchange (ETDEWEB)

    Dunkel, H. (Institut fuer Biotechnologie, Potsdam (German Democratic Republic))

    1989-01-01

    The waste waters obtained from soybean protein are readily accessible by anaerobic methods of treatment, as they contain utilisable C compounds. Acidification of the substrate offers kinetic advantages and is followed by a two-step procedure as the obvious mehtod of biogas production. The process of acidogenesis, which takes place under defined conditions in the acidification reactor, leads to the formation of lactic acid and, to a lesser extent, of acetic acid. The ratios of lactic acid to acetic acid are determined by retention times. As the pH values are low during the preacidification phase (< 4.0), some adjustment is necessary prior to the methane phase. For the process of methanogenesis it is possible to use either packed-bed or fluidized-bed reactors. Quite a number of filling materials were tested. A retention time of 2.0 d allowed a biogas production rate of 6.5 l/lxd to be attained. The methane yield determined in the biogas from the two-stage procedure was on average 10-20% higher than that obtained by one-stage anaerobic treatment. Laboratory analyses permitted the most important constituents to be ascertained on a quantitative basis. (orig.).

  16. Research achievements and application in anaerobic treatment of organic solid wastes--A review

    Institute of Scientific and Technical Information of China (English)

    ZHOU Fuchun; XIONG Deguo; XIAN Xuefu; XU Longjun

    2006-01-01

    Anaerobic digestion is a good method, which possesses the optimal combination of volume reduction, probability of success and potential for resource and energy recovery. However, relatively little research has been done on the anaerobic digestion of organic solid wastes ( OSW ), especially in China.However, different substrates, start-up conditions, micro-organisms, processing technologies, pre-treatment methods could influence the result of anaerobic digestion. Anaerobic treatment of municipal OSW is less than that of wastewaters because some problems and obstructions need to be solved. Meanwhile, the application of anaerobic digestion of OSW is also discussed in the present paper.

  17. Modelling of the mesophilic anaerobic co-digestion of olive mill wastewater with olive mill solid waste using anaerobic digestion model No. 1 (ADM1).

    Science.gov (United States)

    Boubaker, Fezzani; Ridha, Ben Cheikh

    2008-09-01

    The anaerobic digestion model No. 1 (ADM1), conceived by the international water association (IWA) task group for mathematical modelling of anaerobic digestion processes is a structured generic model which includes multiples steps describing biochemical and physicochemical processes encountered in the anaerobic degradation of complex organic substrates and a common platform for further model enhancement and validation of dynamic simulations for a variety of anaerobic processes. In this study the ADM1 model was modified and applied to simulate the mesophilic anaerobic co-digestion of olive mill wastewater (OMW) with olive mill solid waste (OMSW). The ADM1 equations were coded and implemented using the simulation software package MATLAB/Simulink. The most sensitive parameters were calibrated and validated using updated experimental data of our previous work. The results indicated that the ADM1 model could simulate with good accuracy: gas flows, methane and carbon-dioxide contents, pH and total volatile fatty acids (TVFA) concentrations of effluents for various feed concentrations digested at different hydraulic retention times (HRTs) and especially at HRTs of 36 and 24 days. Furthermore, effluent alkalinity and ammonium nitrogen were successfully predicted by the model at HRTs of 12 and 24 days for some feed concentrations.

  18. Investigation of Poultry Waste for Anaerobic Digestion: A Case Study

    Science.gov (United States)

    Salam, Christopher R.

    Anaerobic Digestion (AD) is a biological conversion technology which is being used to produce bioenergy all over the world. This energy is created from biological feedstocks, and can often use waste products from various food and agricultural processors. Biogas from AD can be used as a fuel for heating or for co-generation of electricity and heat and is a renewable substitute to using fossil fuels. Nutrient recycling and waste reduction are additional benefits, creating a final product that can be used as a fertilizer in addition to energy benefits. This project was conducted to investigate the viability of three turkey production wastes as AD feedstock: two turkey litters and a material separated from the turkey processing wastewater using dissolved air flotation (DAF) process. The DAF waste contained greases, oils and other non-commodity portions of the turkey. Using a variety of different process methods, types of bacteria, loading rates and food-to-microorganism ratios, optimal loading rates for the digestion of these three materials were obtained. In addition, the co-digestion of these materials revealed additional energy benefits. In this study, batch digestion tests were carried out to treat these three feedstocks, using mesophilic and thermophilic bacteria, using loading rates of 3 and 6 gVS/L They were tested separately and also as a mixture for co-digestion. The batch reactor used in this study had total and working volumes of 1130 mL and 500 mL, respectively. The initial organic loading was set to be 3 gVS/L, and the food to microorganism ratio was either 0.6 or 1.0 for different treatments based on the characteristics of each material. Only thermophilic (50 +/- 2ºC) temperatures were tested for the litter and DAF wastes in continuous digestion, but mesophilic and thermophilic batch digestion experiments were conducted. The optimum digestion time for all experiments was 14 days. The biogas yields of top litter, mixed litter, and DAF waste under

  19. Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment.

    Science.gov (United States)

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Yuan, Zhiguo

    2016-05-01

    In some wastewater treatment plants (WWTPs), the ever increasing production of sludge with the expanding population overloaded the anaerobic digestion which compromises the sludge reduction efficiency. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, to a very limited extent. This study verified the effectiveness of free nitrous acid (FNA i.e. HNO2) pre-treatment on enhancing full-scale ADS degradation in post anaerobic digestion. The ADS collected from a full-scale WWTP was subject to FNA treatment at concentrations of 0.77, 1.54, 2.31, 3.08, and 3.85 mg N/L for 24 h followed by biochemical methane potential tests. The FNA treatment at all concentrations resulted in an increase (from 1.5-3.1 % compared to the control) in sludge reduction with the highest improvement achieved at 0.77 mg HNO2-N/L. The FNA treatment at this concentration also resulted in the highest increase in methane production (40 %) compared to the control. The economic analysis indicates that FNA treatment is economically attractive for enhancing post anaerobic digestion of full-scale ADS.

  20. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well...

  1. Chemical Hydrolysis and Thermophilic Anaerobic Digestion of Organic Fraction of Municipal Solid Waste

    Directory of Open Access Journals (Sweden)

    Yosvany Díaz Domínguez

    2014-03-01

    Full Text Available The hydrolysis of the macromolecules that compose the organic fraction of municipal solid waste canbe taken for chemical, physical and biological methods, having all as aim the unfolding of the complexmolecules in simplier monomer. Thereby the degradation of organic matter is enhanced and resultsmore efficient the process of biogas via anaerobic. Chemical pretreatments were employed in the workusing sodium hydroxide (NaOH and hydrogen peroxide (H2O2 as reagents.The soluble chemicaloxygen demand (COD, the maximum methane yield and the methane rates production were used toevaluate the pretreatment actions. The degradation of the waste was able to be increased by allowinga comparative analysis to determine the best working conditions for this stage and subsequently itsimpact in the generation of biogas, methane specifically.

  2. Waste activated sludge treatment based on temperature staged and biologically phased anaerobic digestion system.

    Science.gov (United States)

    Yu, Jingwen; Zheng, Mingxia; Tao, Tao; Zuo, Jiane; Wang, Kaijun

    2013-10-01

    The concept of temperature staged and biological phased (TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the effect of temperature (35 to 70 degrees C) as well as the hydraulic retention time (HRT) (2, 4 and 6 days) on the acidogenic phase. The results showed that the solubilization degree of waste-activated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70 degrees C, while the acidification degree was highest at 45 degrees C (17.6%), and this was quite different from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days, 4 days was chosen as the appropriate HRT because of its relatively high solubilization degree (24.6%) and acidification degree (20.1%) at 45 degrees C. The TSBP system combined the acidogenic reactor (45 degrees C, 4 days) with the methanogenic reactor (35 degrees C, 16 days) and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35 degrees C. Moreover, different microbial morphologies were observed in the acidogenic- and methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that 45 degrees C was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufficient system.

  3. Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yifei, E-mail: sunif@buaa.edu.cn [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Wang, Dian; Yan, Jiao [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Qiao, Wei [College of Chemical Science and Engineering, China University of Petroleum, Beijing 102249 (China); Wang, Wei [School of Environment, Tsinghua University, Beijing 100084 (China); Zhu, Tianle [School of Chemistry and Environment, Beihang University, Beijing 100191 (China)

    2014-06-01

    Highlights: • Lipid in municipal biomass would not inhibited the anaerobic digestion process. • A lipid concentration of 65% of total VS was the inhibition concentration. • The amount of Brevibacterium decreased with the increasing of the lipid contents. • Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process. - Abstract: The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2–0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion.

  4. Anaerobic co-digestion of spent coffee grounds with different waste feedstocks for biogas production.

    Science.gov (United States)

    Kim, Jaai; Kim, Hakchan; Baek, Gahyun; Lee, Changsoo

    2016-10-14

    Proper management of spent coffee grounds has become a challenging problem as the production of this waste residue has increased rapidly worldwide. This study investigated the feasibility of the anaerobic co-digestion of spent coffee ground with various organic wastes, i.e., food waste, Ulva, waste activated sludge, and whey, for biomethanation. The effect of co-digestion was evaluated for each tested co-substrate in batch biochemical methane potential tests by varying the substrate mixing ratio. Co-digestion with waste activated sludge had an apparent negative effect on both the yield and production rate of methane. Meanwhile, the other co-substrates enhanced the reaction rate while maintaining methane production at a comparable or higher level to that of the mono-digestion of spent coffee ground. The reaction rate increased with the proportion of co-substrates without a significant loss in methanation potential. These results suggest the potential to reduce the reaction time and thus the reactor capacity without compromising methane production.

  5. Waste sizing solution as co-substrate for anaerobic decolourisation of textile dyeing wastewaters

    NARCIS (Netherlands)

    Bisschops, I.; Santos, dos A.B.; Spanjers, H.

    2005-01-01

    Dyeing wastewaters and residual size are textile factory waste streams that can be treated anaerobically. For successful anaerobic treatment of dyeing effluents, a co-substrate has to be added because of their low concentration of easily biodegradable compounds. Starch-based size contains easily bio

  6. Extracellular polymeric substances and dewaterability of waste activated sludge during anaerobic digestion.

    Science.gov (United States)

    Ye, Fenxia; Liu, Xinwen; Li, Ying

    2014-01-01

    Anaerobic digestion of waste activated sludge was conducted to gain insight into the mechanisms underlying change in sludge dewaterability during its anaerobic digestion. Unexpectedly, the results indicated that sludge dewatering properties measured by capillary suction time only deteriorated after 10 days of anaerobic digestion, after which dewaterability recovered and remained stable. The loosely bound extracellular polymeric substance (LB-EPS) content increased three-fold after 20 days of anaerobic digestion, and did not change significantly during the remaining 30 days. The tightly bound EPS (TB-EPS) content reduced slightly after 20 days of anaerobic digestion, and stabilized during the last 30 days. Polysaccharides (PS) and proteins (PN) content in LB-EPS increased after 10 days of anaerobic digestion. However, PS and PN contents in TB-EPS decreased slightly. The relationship analysis showed that only LB-EPS correlated with dewaterability of the sludge during anaerobic digestion.

  7. Biogas, as a renewable energy source, produced during the anaerobic digestion of organic waste

    CSIR Research Space (South Africa)

    Greben, H

    2009-10-01

    Full Text Available Identifying alternative sources of energy is a matter of urgency, since conventional energy sources are becoming exhausted. Renewable energy sources, such as biogas, can be generated from organic waste, through the anaerobic digestion (AD...

  8. Feasibility assessment of anaerobic digestion technologies for household wastes in Vietnam

    OpenAIRE

    Rodolfo, Daniel Silva; Le, Huang Anh; Koch, Konrad

    2017-01-01

    Anaerobic digestion technologies have been utilized in Vietnam for more than 30 years with thousands of domestic small scale plants, mostly for agricultural and livestock wastes. For municipal solid waste (MSW) the development of biogas plants is far below the current high waste generation rates. The aim of this paper is to present the results of a feasibility assessment of implementing AD to treat the organic fraction of municipal solid waste (OFMSW) in Vietnam. For this purpose, an environm...

  9. A Review of the Anaerobic Digestion of Fruit and Vegetable Waste.

    Science.gov (United States)

    Ji, Chao; Kong, Chui-Xue; Mei, Zi-Li; Li, Jiang

    2017-04-17

    Fruit and vegetable waste is an ever-growing global question. Anaerobic digestion techniques have been developed that facilitate turning such waste into possible sources for energy and fertilizer, simultaneously helping to reduce environmental pollution. However, various problems are encountered in applying these techniques. The purpose of this study is to review local and overseas studies, which focus on the use of anaerobic digestion to dispose fruit and vegetable wastes, discuss the acidification problems and solutions in applying anaerobic digestion for fruit and vegetable wastes and investigate the reactor design (comparing single phase with two phase) and the thermal pre-treatment for processing raw wastes. Furthermore, it analyses the dominant microorganisms involved at different stages of digestion and suggests a focus for future studies.

  10. Anaerobic digestion of autoclaved and untreated food waste.

    Science.gov (United States)

    Tampio, Elina; Ervasti, Satu; Paavola, Teija; Heaven, Sonia; Banks, Charles; Rintala, Jukka

    2014-02-01

    Anaerobic digestion of autoclaved (160°C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids(VS)/m(3)d. Methane yields at all OLR were 5-10% higher for untreated FW (maximum 0.483±0.013 m(3) CH4/kg VS at 3 kg VS/m(3) d) than autoclaved FW (maximum 0.439±0.020 m(3) CH4/kg VS at 4 kg VS/m(3) d). The residual methane potential of both digestates at all OLRs was less than 0.110 m(3) CH4/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.

  11. Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge.

    Science.gov (United States)

    Appels, Lise; Van Assche, Ado; Willems, Kris; Degrève, Jan; Van Impe, Jan; Dewil, Raf

    2011-03-01

    Anaerobic digestion is generally considered to be an economic and environmentally friendly technology for treating waste activated sludge, but has some limitations, such as the time it takes for the sludge to be digested and also the ineffectiveness of degrading the solids. Various pre-treatment technologies have been suggested to overcome these limitations and to improve the biogas production rate by enhancing the hydrolysis of organic matter. This paper studies the use of peracetic acid for disintegrating sludge as a pre-treatment of anaerobic digestion. It has been proved that this treatment effectively leads to a solubilisation of organic material. A maximum increase in biogas production by 21% is achieved. High dosages of PAA lead to a decrease in biogas production. This is due to the inhibition of the anaerobic micro-organisms by the high VFA-concentrations. The evolution of the various VFAs during digestion is studied and the observed trends support this hypothesis.

  12. Steam-explosion pretreatment for enhancing anaerobic digestion of municipal wastewater sludge.

    Science.gov (United States)

    Dereix, Marcela; Parker, Wayne; Kennedy, Kevin

    2006-05-01

    This study evaluated the use of steam explosion as a pretreatment for municipal wastewater treatment sludges and biosolids as a technique for enhancing biogas generation during anaerobic digestion. Samples of dewatered anaerobic digester effluent (biosolids) and a mixture of thickened waste activated sludge (TWAS) and biosolids were steam-exploded under differing levels of intensity in this study. The results indicate that steam explosion can solublize components of these sludge streams. Increasing the intensity of the steam-explosion pressure and temperature resulted in increased solublization. The steam-explosion pretreatment also increased the bioavailability of sludge components under anaerobic digestion conditions. Increasing the steam-explosion intensity increased the ultimate yield of methane during anaerobic digestion. Batch anaerobic digestion tests suggested that pretreatment at 300 psi was the most optimal condition for enhanced biogas generation while minimizing energy input. Semicontinuous anaerobic digestion revealed that the results that were observed in the batch tests were sustainable in prolonged operation. Semicontinuous digestion of the TWAS/biosolids mixture that was pretreated at 300 psi generated approximately 50% more biogas than the controls. Semicontinuous digestion of the pretreated biosolids resulted in a 3-fold increase in biogas compared with the controls. Based on capillary suction test results, steam-explosion pretreatment at 300 psi improved the dewaterability of the final digested sludge by 32 and 45% for the TWAS/ biosolids mixture and biosolids, respectively, compared with controls. The energy requirements of the nonoptimized steam-explosion process were substantially higher than the additional energy produced from enhanced digestion of the pretreated sludge. Substantial improvements in energy efficiency will be required to make the process viable from an energy perspective.

  13. Biogas potential from anaerobic co-digestion of faecal sludge with food waste and garden waste

    Science.gov (United States)

    Afifah, Ukhtiy; Priadi, Cindy Rianti

    2017-03-01

    The limited faecal sludge management can be optimized by converting the sludge into biogas. This study purposed to optimize the biogas potential of faecal sludge with food waste and garden waste. The system using Anaerobic Co-digestion on the variation 25% and 50% concentration of faecal sludge based on Volatile Solids (VS). Inoculum used was cow's rumen. The study was operated using lab-scale batch reactor 51 L for 42 days. Biogas produced at 25% concentration of faecal sludge is 0,30 m3CH4/kg with 71,93% VS and 72,42% COD destruction. Meanwhile, at 50% concentration of faecal sludge produce 0,56 m3CH4/kg VS biogas with 92,43% VS and 87,55% COD destruction. This study concludes that biogas potential of 50% concentration greater than 25% concentration of faecal sludge.

  14. Energy and nutrient recovery from anaerobic treatment of organic wastes

    Science.gov (United States)

    Henrich, Christian-Dominik

    The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an "Ammonia Recovery Process" (ARP) consisting of: (1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, (2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, (3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, (4) high-rate algal post-treatment and finally, (5) an optional anaerobic digestion process for algal and bacterial biomass, and/or supplemental waste fermentation providing the potential for additional nutrient and energy recovery. In addition, the value provided by the waste treatment function of the overall processes, each of the sub-processes would provide valuable co-products offering potential GHG credit through direct fossil-fuel replacement, or replacement of products requiring fossil fuels. These valuable co-products include, (1) ammonium sulfate fertilizer, (2) bacterial biomass, (3) algal biomass providing, high-protein feeds and oils for biodiesel production and, (4) methane bio-fuels. Laboratory and pilot reactors were constructed and operated, providing data supporting the quantification and modeling of the ARP. Growth parameters, and stoichiometric coefficients were determined, allowing for design of the leachate activated sludge treatment sub-component. Laboratory and pilot algal reactors were constructed and operated, and provided data that supported the determination of leachate organic/inorganic-nitrogen ratio, and loading rates, allowing optimum performance of high-rate algal post-treatment. A modular and expandable computer program was developed, which provided a systems model framework capable of predicting individual component

  15. Assessment of anaerobic co-digestion of agro wastes for biogas recovery: A bench scale application to date palm wastes

    Directory of Open Access Journals (Sweden)

    Zainab Ziad Ismail, Ali Raad Talib

    2014-01-01

    Full Text Available Anaerobic digestion is a technology widely used for treatment of organic waste to enhance biogas recovery. In this study, recycling of date palm wastes (DPWs was examined as a source for biogas production. The effects of inoculum addition, pretreatment of substrate, and temperature on the biogas production were investigated in batch mode digesters. Results revealed that the effect of inoculum addition was more significant than alkaline pretreatment of raw waste materials. The biogas recovery from inoculated DPWs exceeds its production from DPWs without inoculation by approximately 140% at mesophilic conditions. Whereby, the increase of biogas recovery from pretreated DPWs was 52% higher than its production from untreated DPWs at mesophilic conditions. The thermophilic conditions improved the biogas yield by approximately 23%. The kinetic of bio-digestion process was well described by modified Gompertz model and the experimental and predicted values of biogas production were fitted well with correlation coefficient values greater than 0.96 suggesting favorable conditions of the process.

  16. Methanogenic community dynamics in anaerobic co-digestion of fruit and vegetable waste and food waste

    Institute of Scientific and Technical Information of China (English)

    Jia Lin; Jiane Zuo; Ruofan Ji; Xiaojie Chen; Fenglin Liu; Kaijun Wang; Yunfeng Yang

    2012-01-01

    A lab-scale continuously-stirred tank reactor (CSTR),used for anaerobic co-digestion of fruit and vegetable waste (FVW) and food waste (FW) at different mixture ratios,was operated for 178 days at the organic loading rate of 3 kg VS (volatile solids)/(m3.day).The dynamics of the Archaeal community and the correlations between environmental variables and methanogenic community structure were analyzed by polymerase chain reactions - denaturing gradient gel electrophoresis (PCR-DGGE) and redundancy analysis (RDA),respectively.PCR-DGGE results demonstrated that the mixture ratio of FVW to FW altered the community composition of Aachaea.As the FVW/FW ratio increased,Methanoculleus,Methanosaeta and Methanosarcina became the predominant methanogens in the community.Redundancy analysis results indicated that the shift of the methanogenic community was significantly correlated with the composition of acidogenic products and methane production yield.Different mixture ratios of substrates led to different compositions of intermediate metabolites,which may affect the methanogenic community.These results suggested that the analysis of microbial communities could be used to diagnose anaerobic processes.

  17. The alternatives for pot-ale disposal. [Evaporation by waste heat recovery and anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, S. (UKAEA Harwell Lab. (UK). Energy Technology Div.)

    1990-01-01

    Pot-ale is a by-product of whisky distilling and when concentrated by evaporation can be sold as cattle feed. Examples of energy savings achieved by recovering waste heat from distilleries and using this waste heat to evaporate the water from the pot-ale are described. Another option for pot-ale disposal is anaerobic digestion to biogas. (UK).

  18. Studies on bacterial activities in aerobic and anaerobic waste water purification.

    Science.gov (United States)

    Adamse, A D; Deinema, M H; Zehnder, A J

    1984-01-01

    Some aspects of the bacteriology of aerobic and anaerobic waste water purification are discussed in view of current opinions and recent developments in the technology of waste water treatment. Various contributions of scientific workers attached to the Department of Microbiology of the Agricultural University, Wageningen, during the past 65 years are summarized. Besides, present investigations are described and research activities in future indicated.

  19. ANAEROBIC TRANSFORMATION OF BIODEGRADABLE WASTE; SIMULTANEOUS PRODUCTION OF ENERGY AND FERTILIZER

    Directory of Open Access Journals (Sweden)

    Amirhossein Malakahmad

    2013-01-01

    Full Text Available Almost 40% of the total waste produced in developing countries is made of biodegradable waste. Typically the waste including the biodegradable portion is transported to the so-called landfills without any segregation process, treatment and utilization in advance. Although mitigation practices such as source reduction, reuse and recycle are essential and required to be practiced in any integrated waste management plan, one of the best approaches to reduce the volume of the waste goes to the landfills is biological transformation. Biological transformation of waste occurs in two major categories; aerobic and anaerobic biodegradation. Anaerobic transformation of biodegradable waste produces methane gas (CH4 which is the valuable source of energy. At first the gas has some impurities such as CO2 and other trace materials which are required to be removed from the main stream before utilization. In addition to methane, the byproduct of the anaerobic process is slurry that can be used as soil amendment agent. It contains several vital elements such as nitrogen, phosphorous and potassium (N, P and K for crops. The quality of slurry is required to be assessed since it affects the soil conditions and plants growth. In this study the importance of biological transformation in waste management systems has been discussed. Different methods and significant factors in methane production via anaerobic digestion have been highlighted and finally, the criteria of produced fertilizer have been elaborated.

  20. ANAEROBIC DIGESTION OF FOOD WASTE AND DAIRY MANURE FOR BIOENERGY PRODUCTION

    Science.gov (United States)

    The performance of continuously mixed anaerobic digesters was evaluated in the laboratory for treating manure, food waste and their mixtures at 35 ± 2oC and a hydraulic retention time of 20 days. The first mixture was composed of 32% and 68%, and the second was composed of 48% and 52% food waste and...

  1. Production of a ruminant protein supplement by anaerobic fermentation of feedlot waste filtrate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, C.A.; Erdman, M.D.

    1977-01-01

    In studies initiated to develop simple and efficient procedures for the production of feed supplements, it was shown that the filtrate from feedlot wastes diluted with water and filtered could be fermented under anaerobic conditions by mixed rumen bacteria, Lactobacilli, or natural microflora from the feedlot wastes to produce a protein-rich feed supplement. The filtrate is low in carbohydrate and therefore supplemental carbohydrate in the form of whey, molasses, starch from potato processing wastes, or corn starch is necessary. Rigid anaerobic conditions need not be maintained nor must aseptic conditions be observed. (JSR)

  2. Enhancement of anaerobic methanogenesis at a short hydraulic retention time via bioelectrochemical enrichment of hydrogenotrophic methanogens.

    Science.gov (United States)

    Li, Yang; Zhang, Yaobin; Liu, Yiwen; Zhao, Zhiqiang; Zhao, Zisheng; Liu, Sitong; Zhao, Huimin; Quan, Xie

    2016-10-01

    Anaerobic digestion (AD) is an important energy strategy for converting organic waste to CH4. A major factor limiting the practical applicability of AD is the relatively long hydraulic retention time (HRT) which declines the treatment efficiency of digesters. A coupling process of anaerobic digestion and 'electromethanogenesis' was proposed to enhance anaerobic digestion at a short HRT in this study. Microorganisms analysis indicated that the electric-biological reactor enriched hydrogenotrophic methanogens in both cathodic biofilm and suspended sludge, helping achieve the high organic removal (71.0% vs 42.3% [control reactor]) and CH4 production (248.5mL/h vs 51.3mL/h), while the additional electric input was only accounted for 25.6% of the energy income from the increased CH4 production. This study demonstrated that a bioelectrochemical enhanced anaerobic reactor could improve the CH4 production and organic removal at a short HRT, providing an economically feasible scheme to treat wastewater.

  3. Microbial community dynamics in mesophilic anaerobic co-digestion of mixed waste.

    Science.gov (United States)

    Supaphol, Savaporn; Jenkins, Sasha N; Intomo, Pichamon; Waite, Ian S; O'Donnell, Anthony G

    2011-03-01

    This paper identifies key components of the microbial community involved in the mesophilic anaerobic co-digestion (AD) of mixed waste at Rayong Biogas Plant, Thailand. The AD process is separated into three stages: front end treatment (FET); feed holding tank and the main anaerobic digester. The study examines how the microbial community structure was affected by the different stages and found that seeding the waste at the beginning of the process (FET) resulted in community stability. Also, co-digestion of mixed waste supported different bacterial and methanogenic pathways. Typically, acetoclastic methanogenesis was the major pathway catalysed by Methanosaeta but hydrogenotrophs were also supported. Finally, the three-stage AD process means that hydrolysis and acidogenesis is initiated prior to entering the main digester which helps improve the bioconversion efficiency. This paper demonstrates that both resource availability (different waste streams) and environmental factors are key drivers of microbial community dynamics in mesophilic, anaerobic co-digestion.

  4. In situ volatile fatty acids influence biogas generation from kitchen wastes by anaerobic digestion.

    Science.gov (United States)

    Xu, Zhiyang; Zhao, Mingxing; Miao, Hengfeng; Huang, Zhenxing; Gao, Shumei; Ruan, Wenquan

    2014-07-01

    Anaerobic digestion is considered to be an efficient way of disposing kitchen wastes, which can not only reduce waste amounts, but also produce biogas. However, the excessive accumulation of volatile fatty acids (VFA) caused by high organic loads will inhibit anaerobic digestion intensively. Effects of the VFA composition on biogas generation and microbial community are still required for the investigation under various organic loads of kitchen wastes. Our results showed that the maximum specific methane production was 328.3 ml g TS(-1), and acetic acid was the main inhibitor in methanogenesis. With the increase of organic load, aceticlastic methanogenesis was more sensitive to acetic acid than hydrogenotrophic methanogenesis. Meanwhile, methanogenic microbial community changed significantly, and few species grew well under excessive organic loads. This study provides an attempt to reveal the mechanism of VFA inhibition in anaerobic digestion of kitchen wastes.

  5. [Characteristics of anaerobic sequencing batch reactor for the treatment of high-solids-content waste].

    Science.gov (United States)

    Wang, Zhi-jun; Wang, Wei; Zhang, Xi-hui

    2006-06-01

    Based on the experiments of digestion of thermo-hydrolyzed sewage sludge in both mesophilic and thermophilic anaerobic sequencing batch reactors (ASBRs) with 20, 10, 7.5, 5d hydraulic retention time (HRT), operating characteristics of ASBR for treatment of high-solids-content waste were investigated. ASBR can efficiently accumulates suspended solids and keep high concentration solids, however there exists a "critical point" of ASBR, which means the maximum capability to accumulate suspended solids without negative effects on ASBR stability, and beyond which the performance deteriorates. Under steady condition, ASBR can sustains high solid retention time (SRT) and mean cell retention time (MCRT), the SRT and MCRT is 2.53 approximately 3.73 and 2.03 approximately 3.14 times of hydraulic retention time (HRT) when treating thermo-hydrolyzed sludge, respectively. Therefore, compared to traditional continuous-flow stirred tank reactor (CSTR), the efficiency of ASBR enhances about 7.13% approximately 34.68%.

  6. Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology.

    Science.gov (United States)

    Moñino, P; Jiménez, E; Barat, R; Aguado, D; Seco, A; Ferrer, J

    2016-10-01

    Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S ratio and favour methanogenic activity in anaerobic treatments. The average methane potential of the food waste was 421±15mLCH4g(-1)VS, achieving 73% anaerobic biodegradability. The anaerobic co-digestion of food waste with WW is expected to increase methane production 2.9-fold. The settleable solids tests and the particle size distribution analyses confirmed that both treatment lines of a conventional WWTP (water and sludge lines) would be clearly impacted by the incorporation of food waste into its influent. Anaerobic processes are therefore preferred over their aerobic counterparts due to their ability to valorise the high COD content to produce biogas (a renewable energy) instead of increasing the energetic costs associated with the aeration process for aerobic COD oxidation.

  7. Potentials for food waste minimization and effects on potential biogas production through anaerobic digestion.

    Science.gov (United States)

    Schott, Anna Bernstad Saraiva; Vukicevic, Sanita; Bohn, Irene; Andersson, Tova

    2013-08-01

    Several treatment alternatives for food waste can result in both energy and nutrient recovery, and thereby potential environmental benefits. However, according to the European Union waste management hierarchy, waste prevention should be the prioritized strategy to decrease the environmental burdens from all solid waste management. The aim of the present study was therefore to investigate the potential for food waste minimization among Swedish households through an investigation of the amount of avoidable food waste currently disposed of. A further aim was to investigate the effect on the national biogas production potential through anaerobic digestion of food waste, considering minimization potentials. A method for waste composition analyses of household food waste, where a differentiation between avoidable and unavoidable food waste is made, was used in a total of 24 waste composition analyses of household waste from Swedish residential areas. The total household food waste generation reached 3.4 kg (household and week)(-1), on average, of which 34% is avoidable. The theoretical methane (CH4) potential in unavoidable food waste reached 442 Ndm(3) (kg VS)(-1) or 128 Nm(3) tonne(-1) wet waste, while the measured (mesophilic CH4 batch tests) CH4 production reached 399 Ndm(3) (kg VS)(-1), which is lower than several previous assessments of CH4 production from household food waste. According to this study the combination of a decrease in food waste generation-in case of successful minimization-and decreased CH4 production from unavoidable food waste will thus result in lower total potential energy recovery from household food waste through anaerobic digestion CH4 potential than previously stated.

  8. Finished leather waste chromium acid extraction and anaerobic biodegradation of the products.

    Science.gov (United States)

    Ferreira, Maria J; Almeida, Manuel F; Pinho, Sílvia C; Santos, Isabel C

    2010-06-01

    Due to the amounts of chromium in the leachate resulting from leather leaching tests, chromium sulfate tanned leather wastes are very often considered hazardous wastes. To overcome this problem, one option could be recovering the chromium and, consequently, lowering its content in the leather scrap. With this objective, chromium leather scrap was leached with sulfuric acid solutions at low temperature also aiming at maximizing chromium removal with minimum attack of the leather matrix. The effects of leather scrap dimension, sulfuric acid and sodium sulfate concentration in the solutions, as well as extraction time and temperature on chromium recovery were studied, and, additionally, organic matrix degradation was evaluated. The best conditions found for chromium recovery were leather scrap conditioning using 25mL of concentrated H(2)SO(4)/L solution at 293 or 313K during 3 or 6days. Under such conditions, 30-60+/-5% of chromium was recovered and as low as 3-6+/-1% of the leather total organic carbon (TOC) was dissolved. Using such treatment, the leather scrap area and volume are reduced and the residue is a more brittle material showing enhanced anaerobic biodegradability. Although good recovery results were achieved, due to the fact that the amount of chromium in eluate exceeded the threshold value this waste was still hazardous. Thus, it needs to be methodically washed in order to remove all the chromium de-linked from collagen.

  9. Methane production enhancement by an independent cathode in integrated anaerobic reactor with microbial electrolysis

    DEFF Research Database (Denmark)

    Cai, Weiwei; Han, Tingting; Guo, Zechong

    2016-01-01

    Anaerobic digestion (AD) represents a potential way to achieve energy recovery from waste organics. In this study, a novel bioelectrochemically-assisted anaerobic reactor is assembled by two AD systems separated by anion exchange membrane, with the cathode placing in the inside cylinder (cathodic...... AD) and the anode on the outside cylinder (anodic AD). In cathodic AD, average methane production rate goes up to 0.070 mL CH4/mL reactor/day, which is 2.59 times higher than AD control reactor (0.027 m3 CH4/m3/d). And COD removal is increased ~15% over AD control. When changing to sludge...... indicates that cathodic AD could cost-effectively enhance methane production rate and degradation of glucose and fermentative liquid....

  10. Start-up performances of dry anaerobic mesophilic and thermophilic digestions of organic solid wastes

    Institute of Scientific and Technical Information of China (English)

    LU Shu-guang; IMAI Tsuyoshi; UKITA Masao; SEKINE Masahiko

    2007-01-01

    Two dry anaerobic digestions of organic solid wastes were conducted for 6 weeks in a lab-scale batch experiment for investigating the start-up performances under mesophilic and thermophilic conditions. The enzymatic activities,i.e., β-glucosidase, β-glucosidase, N-α -benzoyl-L-argininamide (BAA)-hydrolysing protease, urease and phosphatase activities were analysed. The lower BAA-hydrolysing protease activity during the first 2-3 weeks was due to the inhibition of the low pH, but was enhanced simultaneously later with the pH increase. β-glucosidase activity showed the lowest values in weeks 1-2, and recovered simultaneously with the increase of BAA-hydrolysing protease activity. Acetic acid dominated most of the total VFAs in thermophilic digestion, while propionate and butyrate dominated in mesophilic digestion. Thermophilic digestion is confirmed more feasible for achieving better performance against misbalance, especially during the start-up period in a dry anaerobic digestion process.

  11. Potential for energy generation from anaerobic digestion of food waste in Australia.

    Science.gov (United States)

    Lou, Xian Fang; Nair, Jaya; Ho, Goen

    2013-03-01

    Published national and state reports have revealed that Australia deposits an average of 16 million Mg of solid waste into landfills yearly, of which approximately 12.6% is comprised of food. Being highly biodegradable and possessing high energy content, anaerobic digestion offers an attractive treatment option alternative to landfilling. The present study attempted to identify the theoretical maximum benefit of food waste digestion in Australia with regard to energy recovery and waste diversion from landfills. The study also assessed the scope for anaerobic process to utilize waste for energy projects through various case study scenarios. Results indicated anaerobic digestion of total food waste generated across multiple sites in Australia could generate 558 453 dam(3) of methane which translated to 20.3 PJ of heating potential or 1915 GWe in electricity generation annually. This would contribute to 3.5% of total current energy supply from renewable sources. Energy contribution from anaerobic digestion of food waste to the total energy requirement in Australia remains low, partially due to the high energy consumption of the country. However its appropriateness in low density regions, which are prevalent in Australia, may allow digesters to have a niche application in the country.

  12. Performance assessment of two-stage anaerobic digestion of kitchen wastes.

    Science.gov (United States)

    Bo, Zhang; Pin-Jing, He

    2014-01-01

    This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

  13. Anaerobic digestion of bio-waste: A mini-review focusing on territorial and environmental aspects.

    Science.gov (United States)

    Cecchi, Franco; Cavinato, Cristina

    2015-05-01

    Scientific and industrial experiences, together with economical and policies changes of last 30 years, bring anaerobic digestion among the most environmental friendly and economically advantageous technologies for organic waste treatment and management in Europe. In this short review, the role of anaerobic digestion of organic wastes is discussed, considering the opportunity of a territorial friendly approach, without barriers, where different organic wastes are co-treated. This objective can be achieved through two proposed strategies: one is the anaerobic digestion applied as a service for the agricultural and farming sector; the other as a service for citizen (biowaste, diapers and wastewater treatment integration). The union of these two strategies is an environmental- and territorial-friendly process that aims to produce renewable energy and fertiliser material, with a low greenhouse gas emission and nutrients recovery. The advantage of forthcoming application of anaerobic digestion of organic wastes, even for added value bioproducts production and new energy carriers, are finally discussed. Among several advantages of anaerobic digestion, the role of the environmental controller was evaluated, considering the ability of minimising the impacts exploiting the biochemical equilibrium and sensitivity as a quality assurance for digestate. © The Author(s) 2015.

  14. Enhanced biogas yield from energy crops with rumen anaerobic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Prochazka, Jindrich; Zabranska, Jana; Dohanyos, Michal [Department of Water Technology and Environmental Engineering, Faculty of Environmental Technology, Institute of Chemical Technology in Prague, Prague (Czech Republic); Mrazek, Jakub; Strosova, Lenka; Fliegerova, Katerina [Laboratory of Anaerobic Microbiology, Institute of Animal Physiology and Genetics, CAS, v.v.i., Prague (Czech Republic)

    2012-06-15

    Anaerobic fungi (AF) are able to degrade crop substrates with higher efficiency than commonly used anaerobic bacteria. The aim of this study was to investigate ways of use of rumen AF to improve biogas production from energy crops under laboratory conditions. In this study, strains of AF isolated from feces or rumen fluid of cows and deer were tested for their ability to integrate into the anaerobic bacterial ecosystem used for biogas production, in order to improve degradation of substrate polysaccharides and consequently the biogas yield. Batch culture, fed batch culture, and semicontinuous experiments have been performed using anaerobic sludge from pig slurry fermentation and different kinds of substrates (celluloses, maize, and grass silage) inoculated by different genera of AF. All experiments showed a positive effect of AF on the biogas yield and quality. AF improved the biogas production by 4-22%, depending on the substrate and AF species used. However, all the cultivation experiments indicated that rumen fungi do not show long-term survival in fermenters with digestate from pig slurry. The best results were achieved during fed batch experiment with fungal culture Anaeromyces (KF8), in which biogas production was enhanced during the whole experimental period of 140 days. This result has not been achieved in semicontinuous experiment, where increment in biogas production in fungal enriched reactor was only 4% after 42 days. (copyright 2012 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. The application of biotechnology on the enhancing of biogas production from lignocellulosic waste.

    Science.gov (United States)

    Wei, Suzhen

    2016-12-01

    Anaerobic digestion of lignocellulosic waste is considered to be an efficient way to answer present-day energy crisis and environmental challenges. However, the recalcitrance of lignocellulosic material forms a major obstacle for obtaining maximum biogas production. The use of biological pretreatment and bioaugmentation for enhancing the performance of anaerobic digestion is quite recent and still needs to be investigated. This paper reviews the status and perspectives of recent studies on biotechnology concept and investigates its possible use for enhancing biogas production from lignocellulosic waste with main emphases on biological pretreatment and bioaugmentation techniques.

  16. Anaerobic co-digestion of agro-food waste mixtures in a fed-batch basis.

    Science.gov (United States)

    Hidalgo, Dolores; Martín-Marroquín, Jesús M; Nieto, Pedro

    2016-10-01

    The agro-food industry (including livestock) generates millions of tonnes of waste products. A solution to this sector's waste disposal challenges was explored by a joint treatment model of organic waste products from several industries. An inventory of agro-food industry organic waste streams with high potential for biogas production was carried out in a logistically viable area (Cider Region, Asturias, Spain). Three industries were selected as those with the higher potential for this study: livestock, dairy and beverage. The kinetics of anaerobic degradation and methane production of four mixtures of selected waste streams were investigated. The specific methane production at five different substrate-to-inoculum ratios (0.50, 0.75, 1.00, 1.50 and 2.00) showed a slightly decreasing trend at the higher ratios. Some hints of a synergistic effect have been observed in mixtures with higher content in milled apple waste, while antagonistic symptoms were noted in mixtures mainly composed of dairy wastes. The estimation of fluxes of waste and methane potentials in the Cider Region suggests centralised anaerobic digestion as a sustainable solution for the valorisation of livestock and agro-food wastes generated in this area. Sector-specific waste streams (livestock and agro-food industry) could cover up to 12% of regional total energy demand.

  17. Comparison of high-solids to liquid anaerobic co-digestion of food waste and green waste.

    Science.gov (United States)

    Chen, Xiang; Yan, Wei; Sheng, Kuichuan; Sanati, Mehri

    2014-02-01

    Co-digestion of food waste and green waste was conducted with six feedstock mixing ratios to evaluate biogas production. Increasing the food waste percentage in the feedstock resulted in an increased methane yield, while shorter retention time was achieved by increasing the green waste percentage. Food waste/green waste ratio of 40:60 was determined as preferred ratio for optimal biogas production. About 90% of methane yield was obtained after 24.5 days of digestion, with total methane yield of 272.1 mL/g VS. Based the preferred ratio, effect of total solids (TS) content on co-digestion of food waste and green waste was evaluated over a TS range of 5-25%. Results showed that methane yields from high-solids anaerobic digestion (15-20% TS) were higher than the output of liquid anaerobic digestion (5-10% TS), while methanogenesis was inhibited by further increasing the TS content to 25%. The inhibition may be caused by organic overloading and excess ammonia.

  18. Mechanism and kinetics model of hydrolysis in anaerobic digestion of kitchen wastes

    Institute of Scientific and Technical Information of China (English)

    吴云; 张代钧; 杨钢

    2009-01-01

    The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.

  19. Study on the inhibition of methane production from anaerobic digestion of biodegradable solid waste.

    Science.gov (United States)

    Tiantao Zhao; Lijie Zhang; Youcai Zhao

    2010-04-01

    The inhibition effects and mechanisms of chlorinated methane, anthraquinone and acetylene on methanogenesis in the anaerobic digestion process of biodegradable solid wastes were investigated. It was found that both chloroform and acetylene could effectively inhibit methanogens. Acetylene inhibited the activity of methanogens, while chloroform inhibited metabolic process of methanogenesis. A central composite design (CCD) and response surface regression analysis (RSREG) were employed to determine the optimum conditions and interaction effects of chloroform and acetylene in terms of methane and hydrogen production. Acetylene promoted the inhibition efficiency (F = 31.14; P 0.05). In addition, a maximum hydrogen production of 1.6 ml was estimated under the optimum conditions of chloroform concentration of 6.69 mg kg(-1) and acetylene concentration of 3.08 x 10(-3) (v/v). Chloroform had a significant effect on enhancing the production of propionic acid and a minimum molar ratio of acetic acid to propionic acid of 0.707 was reached with the chloroform concentration of 9.24 mg kg(-1) and acetylene concentration of 4.0 x 10(-3) (v/v). Hence, methanogens can be inhibited while the stabilization process of solid wastes can still work well. Moreover, co-inhibition technology practice at landfills was feasible and the environmental damage was negligible, according to the analysis and experimental results.

  20. Anaerobic composting of waste organic fraction. Compostaje anaerobico de la fraccion organica de los residuos

    Energy Technology Data Exchange (ETDEWEB)

    Baere, L. de; Verdonck, O.; Verstraete, W.

    1994-01-01

    The dry anaerobic composting can be carried out in mesophilic and thermophilic conditions. Gas production of 6,2 and 8.5 m''3 biogas m''3 daily in laboratory fermenters was obtained. The quality of waste is higher than obtained in aerobic process. The streptococcus sludge was destroyed. This experimental can be applied for big scale and it permits energy recovery and organic compost of municipal solid wastes. (Author)

  1. Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Bilgili, M. Sinan [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: mbilgili@yildiz.edu.tr; Demir, Ahmet [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: ahmetd@yildiz.edu.tr; Ozkaya, Bestamin [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: bozkaya@yildiz.edu.tr

    2007-05-08

    In this study, the effect of leachate recirculation on aerobic and anaerobic degradation of municipal solid wastes is determined by four laboratory-scale landfill reactors. The options studied and compared with the traditional anaerobic landfill are: leachate recirculation, landfill aeration, and aeration with leachate recirculation. Leachate quality is regularly monitored by the means of pH, alkalinity, total dissolved solids, conductivity, oxidation-reduction potential, chloride, chemical oxygen demand, ammonia, and total Kjeldahl nitrogen, in addition to generated leachate quantity. Aerobic leachate recirculated landfill appears to be the most effective option in the removal of organic matter and ammonia. The main difference between aerobic recirculated and non-recirculated landfill options is determined at leachate quantity. Recirculation is more effective on anaerobic degradation of solid waste than aerobic degradation. Further studies are going on to determine the optimum operational conditions for aeration and leachate recirculation rates, also with the operational costs of aeration and recirculation.

  2. Thermophilic anaerobic waste water treatment, temperature aspects and process stability.

    NARCIS (Netherlands)

    Lier, van J.B.

    1995-01-01

    The main objective of this thesis was to assess the thermostability of thermophilic anaerobic wastewater treatment processes and the possibility to optimize the performance of thermophilic high-rate systems.Experiments were conducted to study the suitability of two types of seed material to start a

  3. Mesophilic anaerobic co-digestion of municipal solid waste and sewage sludge

    DEFF Research Database (Denmark)

    Aghdam, Ehsan Fathi; Kinnunen, V.; Rintala, Jukka A.

    2015-01-01

    This paper presents mesophilic anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW), biowaste (BW), sewage sludge (SS), and co-digestion of BW and SS. Average methane yields of 386 ± 54, 385 ± 82, 198 ± 14, and 318 ± 59 L CH4/kg volatile solids (VS) were obtained for OFMSW...

  4. Full scale demonstration plant for anaerobic digestion of sorted municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Szikriszt, G.; Koehlin, S.-E.; Kaellersjoe, L. (BIOMET AB, Sundbyberg (SE)); Frostell, B. (Swedish Environmental Research Institute, Stockholm (SE))

    1992-01-01

    A possible future alternative for the treatment of organic material inmunicipal solid waste is anaerobic digestion at a TS concentration of around 10%. The results from a successful pilot plant experiment were reported. An existing 900 m{sup 3} full scale anaerobic digester for municipal sludge was reconstructed for digestion of a mixture of sorted municipal solid waste and municipal sludge. The reconstruction of the anaerobic digester system involved the installation of a novel milling stage for size reduction of incoming waste, removal of unsuitable materials, such as glass, metals etc and preparation of a feedstock with a TS concentration of 10%. The anaerobic digester has been equipped with a mechanical mixing system. The system also comprises an internal water recirculation system, allowing a minimal production of waste water for further treatment. The retrofitted digester was started in September 1991 and the milling station and the separation system in April 1992. During the demonstration operation, the interest is focused on the following key areas: May the succesful results in a 20 m{sup 3} pilot plant be realised also on a full scale Is it possible to solve potential accumulation problems Is the reliability and durability of the milling equipment chosen In the paper, the full scale plant is presented as well as initial results of operation. (au).

  5. A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric;

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household was...... from digested household wastes. This study provided a culture with a potential to be applied in reactor systems for extreme thermophilic H-2 production from complex organic wastes.......The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

  6. Biogas production from livestock waste anaerobic digesters: evaluation and optimization

    Science.gov (United States)

    Livestock wastes can serve as the feedstock for biogas production (mainly methane) that could be used as alternative energy source. The green energy derived from animal wastes is considered to be carbon neutral and offsetting those generated from fossil fuels. However, feedstocks from livestock re...

  7. Effect of ultrasonication on anaerobic degradability of solid waste digestate.

    Science.gov (United States)

    Boni, M R; D'Amato, E; Polettini, A; Pomi, R; Rossi, A

    2016-02-01

    This paper evaluates the effect of ultrasonication on anaerobic biodegradability of lignocellulosic residues. While ultrasonication has been commonly applied as a pre-treatment of the feed substrate, in the present study a non-conventional process configuration based on recirculation of sonicated digestate to the biological reactor was evaluated at the lab-scale. Sonication tests were carried out at different applied energies ranging between 500 and 50,000kJ/kg TS. Batch anaerobic digestion tests were performed on samples prepared by mixing sonicated and untreated substrate at two different ratios (25:75 and 75:25 w/w). The results showed that when applied as a post-treatment of digestate, ultrasonication can positively affect the yield of anaerobic digestion, mainly due to the dissolution effect of complex organic molecules that have not been hydrolyzed by biological degradation. A good correlation was found between the CH4 production yield and the amount of soluble organic matter at the start of digestion tests. The maximum gain in biogas production was 30% compared to that attained with the unsonicated substrate, which was tentatively related to the type and concentration of the metabolic products.

  8. Efficiency of the anaerobic treatment of the organic fraction of municipal solid waste: collection and pretreatment

    DEFF Research Database (Denmark)

    Hartmann, Hinrich; Møller, H.B.; Ahring, Birgitte Kiær

    2004-01-01

    of the principles of the anaerobic digestion process and to an optimization of its large-scale implementation. In order to get an overview of the current situation concerning the treatment of the organic fraction of municipal solid waste (OFMSW) in Denmark, interviews were carried out with operators of the biogas...... plants where OFMSW is treated and the municipality staff responsible for waste management. With the aim of fulfilling the governmental goal to treat 150 000 tons of OFMSW by the year 2004 mainly by anaerobic digestion, the different municipalities are investigating different concepts of waste collection...... and treatment. The quality of the OFMSW treated is the key to smooth operation of the biogas process including a high biogas yield and production of an effluent that is feasible for use as fertilizer on agricultural land. Comparison of the different concepts leads to the conclusion that source-sorting of OFMSW...

  9. Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

    Science.gov (United States)

    Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

    2013-03-01

    Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates.

  10. Anaerobic Treatment of Municipal Solid Waste and Sludge for Energy Production and Recycling of Nutrients

    Science.gov (United States)

    Leinonen, S.

    This volume contains 18 papers presented at a Nordic workshop dealing with application of anaerobic decomposition processes on various types of organic wastes, held at the Siikasalmi Research and Experimental Station of the University of Joensuu on 1-2 Oct. 1992. Subject coverage of the presentations extends from the biochemical and microbiological principles of organic waste processing to descriptions and practical experiences of various types of treatment plants. The theoretical and experimental papers include studies on anaerobic and thermophilic degradation processes, methanogenesis, effects of hydrogen, treatment of chlorinated and phenolic compounds, and process modeling, while the practical examples range from treatment of various types of municipal, industrial, and mining wastes to agricultural and fish farm effluents. The papers provide technical descriptions of several biogas plants in operation. Geographically, the presentations span the Nordic and Baltic countries.

  11. Dynamics of biofilm formation during anaerobic digestion of organic waste.

    Science.gov (United States)

    Langer, Susanne; Schropp, Daniel; Bengelsdorf, Frank R; Othman, Maazuza; Kazda, Marian

    2014-10-01

    Biofilm-based reactors are effectively used for wastewater treatment but are not common in biogas production. This study investigated biofilm dynamics on biofilm carriers incubated in batch biogas reactors at high and low organic loading rates for sludge from meat industry dissolved air flotation units. Biofilm formation and dynamics were studied using various microscopic techniques. Resulting micrographs were analysed for total cell numbers, thickness of biofilms, biofilm-covered surface area, and the area covered by extracellular polymeric substances (EPS). Cell numbers within biofilms (10(11) cells ml(-1)) were up to one order of magnitude higher compared to the numbers of cells in the fluid reactor content. Further, biofilm formation and structure mainly correlated with the numbers of microorganisms present in the fluid reactor content and the organic loading. At high organic loading (45 kg VS m(-3)), the thickness of the continuous biofilm layer ranged from 5 to 160 μm with an average of 51 μm and a median of 26 μm. Conversely, at lower organic loading (15 kg VS m(-3)), only microcolonies were detectable. Those microcolonies increased in their frequency of occurrence during ongoing fermentation. Independently from the organic loading rate, biofilms were embedded completely in EPS within seven days. The maturation and maintenance of biofilms changed during the batch fermentation due to decreasing substrate availability. Concomitant, detachment of microorganisms within biofilms was observed simultaneously with the decrease of biogas formation. This study demonstrates that biofilms of high cell densities can enhance digestion of organic waste and have positive effects on biogas production.

  12. Minimizing asynchronism to improve the performances of anaerobic co-digestion of food waste and corn stover.

    Science.gov (United States)

    Zhou, Qi; Shen, Fei; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Jaffu, Muhanmad; Chufo, Akiber; Li, Xiujin

    2014-08-01

    To investigate the existence of the asynchronism during the anaerobic co-digestion of different substrates, two typical substrates of food waste and corn stover were anaerobically digested with altering organic loadings (OL). The results indicated that the biodegradability of food waste and corn stover was calculated to be 81.5% and 55.1%, respectively, which was main reason causing the asynchronism in the co-digestion. The asynchronism was minimized by NaOH-pretreatment for corn stover, which could improve the biodegradability by 36.6%. The co-digestion with pretreatment could increase the biomethane yield by 12.2%, 3.2% and 0.6% comparing with the co-digestion without pretreatment at C/N ratios of 20, 25 and 30 at OL of 35 g-VS/L, respectively. The results indicated that the digestibility synchronism of food waste and corn stover was improved through enhancing the accessibility and digestibility of corn stover. The biomethane production could be increased by minimizing the asynchronism of two substrates in co-digestion.

  13. Development of microorganisms during storage of wet brewery waste under aerobic and anaerobic conditions

    Directory of Open Access Journals (Sweden)

    Leiliane Cristine de Souza

    2012-01-01

    Full Text Available This research study was conducted to evaluate, by means of microbiological analyses, the preservation of wet brewery waste stored under aerobic and anaerobic conditions, regarding the development of filamentous fungi, yeasts and lactic-acid bacteria. The following treatments were used: untreated brewery waste, pre-dried brewery waste silage, brewery waste silage with effluent drainage and BW silage without effluent drainage. Silos made of PVC and equipped with Bunsen valves to allow gases to escape were used. Dry matter (DM, crude protein (CP, temperature (°C and pH in the untreated BW, in the stored brewery waste and in the brewery waste silage upon silo opening, after 60 days of ensilage were analyzed. A completely randomized design was used. The data were subjected to analysis of variance, and the means were compared by the Tukey test at the 5% probability level. The preservation of brewery waste packaged under aerobic conditions was not appropriate due to the development of filamentous fungi and yeasts; however, storage under anaerobic conditions proved to be an effective conservation process.

  14. Influence of lactic acid on the two-phase anaerobic digestion of kitchen wastes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; CAI Wei-min; HE Pin-jing

    2007-01-01

    To evaluate the influence of lactic acid on the methanogenesis, anaerobic digestion of kitchen wastes was firstly conducted in a two-phase anaerobic digestion process, and performance of two digesters fed with lactic acid and glucose was subsequently compared.The results showed that the lactic acid was the main fermentation products of hydrolysis-acidification stage in the two-phase anaerobic digestion process for kitchen wastes. The lactic acid concentration constituted approximately 50% of the chemical oxygen demand (COD) concentration in the hydrolysis-acidification liquid. The maximum organic loading rate was lower in the digester fed with lactic acid than that fed with glucose. Volatile fatty acids (VFAs) and COD removal were deteriorated in the methanogenic reactor fed with to the high concentration of lactic acid fed. It could be concluded that avoiding the presence of the lactic acid is necessary in the hydrolysis-acidification process for the improvement of the two-phase anaerobic digestion process of kitchen wastes.

  15. Application of the Initial Rate Method in Anaerobic Digestion of Kitchen Waste

    Directory of Open Access Journals (Sweden)

    Lei Feng

    2017-01-01

    Full Text Available This article proposes a methane production approach through sequenced anaerobic digestion of kitchen waste, determines the hydrolysis constants and reaction orders at both low total solid (TS concentrations and high TS concentrations using the initial rate method, and examines the population growth model and first-order hydrolysis model. The findings indicate that the first-order hydrolysis model better reflects the kinetic process of gas production. During the experiment, all the influential factors of anaerobic fermentation retained their optimal values. The hydrolysis constants and reaction orders at low TS concentrations are then employed to demonstrate that the first-order gas production model can describe the kinetics of the gas production process. At low TS concentrations, the hydrolysis constants and reaction orders demonstrated opposite trends, with both stabilizing after 24 days at 0.99 and 1.1252, respectively. At high TS concentrations, the hydrolysis constants and the reaction orders stabilized at 0.98 (after 18 days and 0.3507 (after 14 days, respectively. Given sufficient reaction time, the hydrolysis involved in anaerobic fermentation of kitchen waste can be regarded as a first-order reaction in terms of reaction kinetics. This study serves as a good reference for future studies regarding the kinetics of anaerobic digestion of kitchen waste.

  16. Utilization of vegetable dumplings waste from industrial production by anaerobic digestion

    Science.gov (United States)

    Pilarska, Agnieszka A.; Pilarski, Krzysztof; Ryniecki, Antoni; Tomaszyk, Kamila; Dach, Jacek; Wolna-Maruwka, Agnieszka

    2017-01-01

    This paper provides the analysis of results of biogas and methane yield for vegetable dumplings waste: dough with fat, vegetable waste, and sludge from the clarifier. Anaerobic digestion of food waste used in the experiments was stable after combining the substrates with a digested pulp composed of maize silage and liquid manure (as inoculum), at suitable ratios. The study was carried out in a laboratory scale using anaerobic batch reactors, at controlled (mesophilic) temperature and pH conditions. The authors present the chemical reactions accompanying biodegradation of the substrates and indicate the chemical compounds which may lead to acidification during the anaerobic digestion. An anaerobic digestion process carried out with the use of a dough-and-fat mixture provided the highest biogas and methane yields. The following yields were obtained in terms of fresh matter: 242.89 m3 Mg-1 for methane and 384.38 m3 Mg-1 for biogas, and in terms of volatile solids: 450.73 m3 Mg-1 for methane and 742.40 m3 Mg-1 for biogas. Vegetables and sludge from the clarifier (as fresh matter) provided much lower yields.

  17. Application of the Initial Rate Method in Anaerobic Digestion of Kitchen Waste

    Science.gov (United States)

    Lang, Xianming; Liu, Yiwei; Li, Rundong; Yu, Meiling; Shao, Lijie; Wang, Xiaoming

    2017-01-01

    This article proposes a methane production approach through sequenced anaerobic digestion of kitchen waste, determines the hydrolysis constants and reaction orders at both low total solid (TS) concentrations and high TS concentrations using the initial rate method, and examines the population growth model and first-order hydrolysis model. The findings indicate that the first-order hydrolysis model better reflects the kinetic process of gas production. During the experiment, all the influential factors of anaerobic fermentation retained their optimal values. The hydrolysis constants and reaction orders at low TS concentrations are then employed to demonstrate that the first-order gas production model can describe the kinetics of the gas production process. At low TS concentrations, the hydrolysis constants and reaction orders demonstrated opposite trends, with both stabilizing after 24 days at 0.99 and 1.1252, respectively. At high TS concentrations, the hydrolysis constants and the reaction orders stabilized at 0.98 (after 18 days) and 0.3507 (after 14 days), respectively. Given sufficient reaction time, the hydrolysis involved in anaerobic fermentation of kitchen waste can be regarded as a first-order reaction in terms of reaction kinetics. This study serves as a good reference for future studies regarding the kinetics of anaerobic digestion of kitchen waste. PMID:28546964

  18. Environmental assessment of energy generation from agricultural and farm waste through anaerobic digestion.

    Science.gov (United States)

    Nayal, Figen Sisman; Mammadov, Aydin; Ciliz, Nilgun

    2016-12-15

    While Turkey is one of the world's largest producers and exporters of agricultural goods, it is also, at the same time a net importer of energy carriers. This dichotomy offers a strong incentive to generate energy from agricultural and farming waste; something which could provide energy security for rural areas. Combined with the enhanced energy security for farming areas, the production of energy in this manner could conceivably contribute to the overall national effort to reduce the Turkey's carbon footprint. This study explores the environmental benefits and burdens of one such option, that is, biogas production from a mixture of agricultural and animal waste through anaerobic digestion (AD), and its subsequent use for electricity and heat generation. A life-cycle assessment methodology was used, to measure the potential environmental impact of this option, in terms of global warming and total weighed impact, and to contrast it with the impact of producing the same amount of energy via an integrated gasification combined cycle process and a hard coal power plant. This study concentrates on an AD and cogeneration pilot plant, built in the Kocaeli province of Turkey and attempts to evaluate its potential environmental impacts. The study uses laboratory-scale studies, as well as literature and LCI databases to derive the operational parameters, yield and emissions of the plant. The potential impacts were calculated with EDIP 2003 methodology, using GaBi 5 LCA software. The results indicate that N2O emissions, resulting from the application of liquid and solid portions of digestate (a by-product of AD), as an organic fertilizer, are by far the largest contributors to global warming among all the life cycle stages. They constitute 68% of the total, whereas ammonia losses from the same process are the leading cause of terrestrial eutrophication. The photochemical ozone formation potential is significantly higher for the cogeneration phase, compared to other life cycle

  19. determining the optimum proportion of shea waste in anaerobic co ...

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    In search for an alternative source of energy, various feedstocks and wastes are being investi- gated to identify ... energy supply (Zauner and Kuntzel, 1986). Biogas comprises ... as it has been widely reported that high long-chain fatty acids.

  20. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    Science.gov (United States)

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency.

  1. Benzene removal by a novel modification of enhanced anaerobic biostimulation.

    Science.gov (United States)

    Xiong, Wenhui; Mathies, Chris; Bradshaw, Kris; Carlson, Trevor; Tang, Kimberley; Wang, Yi

    2012-10-01

    A novel modification of enhanced anaerobic bioremediation techniques was developed by using non-activated persulfate to accelerate the organic phosphorus breakdown and then stimulate benzene biodegradation by nitrate and sulfate reduction. Benzene concentrations in groundwater where nitrate, triethyl phosphate and persulfate were successfully injected were reduced at removal efficiencies greater than 77% to the levels below the applicable guideline. Soil benzene was removed effectively by the modification of the enhanced anaerobic bioremediation with removal efficiencies ranging between 75.9% and 92.8%. Geochemical analytical results indicated that persulfate effectively breaks down triethyl phosphate into orthophosphate, thereby promoting nitrate and sulfate utilization. Microbial analyses (quantitative polymerase chain reaction, denaturing gradient gel electrophoresis and 16S ribosomal RNA) demonstrated that benzene was primarily biodegraded by nitrate reduction while sulfate reduction played an important role in benzene removal at some portions of the study site. Enrichment in the heavier carbon isotope ¹³C of residual benzene with the increased removal efficiency provided direct evidence for benzene biodegradation. Nitrogen, sulfur and oxygen isotope analyses indicated that both nitrate reduction and sulfate reduction were occurring as bioremediation mechanisms.

  2. Impact of pretreatment on solid state anaerobic digestion of yard waste for biogas production.

    Science.gov (United States)

    Zhang, Zhikai; Li, Wangliang; Zhang, Guangyi; Xu, Guangwen

    2014-02-01

    Solid state anaerobic digestion, as a safe and environment-friendly technology to dispose municipal solid wastes, can produce methane and reduce the volume of wastes. In order to raise the digestion efficiency, this study investigated the pretreatment of yard waste by thermal or chemical method to break down the complex lignocellulosic structure. The composition and structure of pretreated yard waste were analyzed and characterized. The results showed that the pretreatment decreased the content of cellulose and hemicelluloses in yard waste and in turn improved the hydrolysis and methanogenic processes. The thermal pretreatment sample (P1) had the highest methane yield, by increasing 88% in comparison with digesting the raw material. The maximum biogas production reached 253 mL/g volatile solids (VS). The largest substrate mass reduction was obtained by the alkaline pretreatment (P5). The VS of the alkaline-treated sample decreased about 60% in comparison with the raw material.

  3. The role of zero valent iron on the fate of tetracycline resistance genes and class 1 integrons during thermophilic anaerobic co-digestion of waste sludge and kitchen waste.

    Science.gov (United States)

    Gao, Pin; Gu, Chaochao; Wei, Xin; Li, Xiang; Chen, Hong; Jia, Hanzhong; Liu, Zhenhong; Xue, Gang; Ma, Chunyan

    2017-03-15

    Activated sludge has been identified as a potential significant source of antibiotic resistance genes (ARGs) to the environment. Anaerobic digestion is extensively used for sludge stabilization and resource recovery, and represents a crucial process for controlling the dissemination of ARGs prior to land application of digested sludge. The objective of this study is to investigate the effect of zero valent iron (Fe(0)) on the attenuation of seven representative tetracycline resistance genes (tet, tet(A), tet(C), tet(G), tet(M), tet(O), tet(W), and tet(X)), and the integrase gene intI1 during thermophilic anaerobic co-digestion of waste sludge and kitchen waste. Significant decrease (P  0.05) were found for all gene targets between digesters with Fe(0) dosages of 5 and 60 g/L. A first-order kinetic model favorably described the trends in concentrations of tet and intI1 gene targets during thermophilic anaerobic digestion with or without Fe(0). Notably, tet genes encoding different resistance mechanisms behaved distinctly in anaerobic digesters, although addition of Fe(0) could enhance their reduction. The overall results of this research suggest that thermophilic anaerobic digestion with Fe(0) can be a potential alternative technology for the attenuation of tet and intI1 genes in waste sludge.

  4. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling.

    Science.gov (United States)

    Fitamo, T; Boldrin, A; Dorini, G; Boe, K; Angelidaki, I; Scheutz, C

    2016-12-01

    Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop strategies for controlling and optimising the co-digestion process. The model parameters were maintained in the same way as the original dynamic bioconversion model, albeit with minor adjustments, to simulate the co-digestion of food and garden waste with mixed sludge from a wastewater treatment plant in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation scenario analysis demonstrated that increasing the amount of mixed sludge in the co-substrate had a marginal effect on the reactor performance. In contrast, increasing the amount of food waste and garden waste resulted in improved performance.

  5. Dark fermentation of complex waste biomass for biohydrogen production by pretreated thermophilic anaerobic digestate.

    Science.gov (United States)

    Ghimire, Anish; Frunzo, Luigi; Pontoni, Ludovico; d'Antonio, Giuseppe; Lens, Piet N L; Esposito, Giovanni; Pirozzi, Francesco

    2015-04-01

    The Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1 ± 7.3 ml H2/g VS) to buffalo manure (135.6 ± 4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6 ± 4.1 ml H2/g VS), fennel waste (58.1 ± 29.8 ml H2/g VS), olive pomace (54.9 ± 5.4 ml H2/g VS) and olive mill wastewater (46.0 ± 15.6 ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways.

  6. Anaerobic co-digestion of food waste and dairy manure: effects of food waste particle size and organic loading rate.

    Science.gov (United States)

    Agyeman, Fred O; Tao, Wendong

    2014-01-15

    This study was to comprehensively evaluate the effects of food waste particle size on co-digestion of food waste and dairy manure at organic loading rates increased stepwise from 0.67 to 3 g/L/d of volatile solids (VS). Three anaerobic digesters were fed semi-continuously with equal VS amounts of food waste and dairy manure. Food waste was ground to 2.5 mm (fine), 4 mm (medium), and 8 mm (coarse) for the three digesters, respectively. Methane production rate and specific methane yield were significantly higher in the digester with fine food waste. Digestate dewaterability was improved significantly by reducing food waste particle size. Specific methane yield was highest at the organic loading rate of 2g VS/L/d, being 0.63, 0.56, and 0.47 L CH4/g VS with fine, medium, and coarse food waste, respectively. Methane production rate was highest (1.40-1.53 L CH4/L/d) at the organic loading rate of 3 g VS/L/d. The energy used to grind food waste was minor compared with the heating value of the methane produced.

  7. Mixing effect on thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

    KAUST Repository

    Ghanimeh, Sophia A.

    2012-08-01

    This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314l CH 4/gVS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825mg HAc/l, propionate content from 2073 to 488mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5gVS/l/d in comparison to 1.9gVS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10gVSS/l and enhanced solids and soluble COD removal. © 2012 Elsevier Ltd.

  8. Evaluating a model of anaerobic digestion of organic wastes through system identification

    Energy Technology Data Exchange (ETDEWEB)

    Anex, R.P.; Kiely, G.

    1999-07-01

    Anaerobic digestion of the organic fraction of municipal solid waste (MSW), on its own or co-digested with primary sewage sludge (PSS), produces high quality biogas, suitable as renewable energy. Parameter estimation and evaluation of a two-stage mathematical model of the anaerobic co-digestion of the organic fraction of MSW and PSS are described. Measured data are from a bench scale laboratory experiment using a continuously stirred tank reactor and operated at 36 C for 115 days. The two-stage model simulates acidogenesis and methanogenesis, including ammonia inhibition. Model parameters are estimated using an output error, Levenberg-Marquardt (LM) algorithm. Sensitivity of the estimated parameter values and the model outputs to non-estimated model parameters and measurement errors are evaluated. The estimated mathematical model successfully predicts the performance of the anaerobic reactor. Sensitivity results provide guidance for improving the model structure and experimental procedures.

  9. Increased anaerobic production of methane by co-digestion of sludge with microalgal biomass and food waste leachate.

    Science.gov (United States)

    Kim, Jungmin; Kang, Chang-Min

    2015-01-01

    The co-digestion of multiple substrates is a promising method to increase methane production during anaerobic digestion. However, limited reliable data are available on the anaerobic co-digestion of food waste leachate with microalgal biomass. This report evaluated methane production by the anaerobic co-digestion of different mixtures of food waste leachate, algal biomass, and raw sludge. Co-digestion of substrate mixture containing equal amounts of three substrates had higher methane production than anaerobic digestion of individual substrates. This was possibly due to a proliferation of methanogens over the entire digestion period induced by multistage digestion of different substrates with different degrees of degradability. Thus, the co-digestion of food waste, microalgal biomass, and raw sludge appears to be a feasible and efficient method for energy conversion from waste resources.

  10. Effect of the presence of the antimicrobial tylosin in swine waste on anaerobic treatment.

    Science.gov (United States)

    Angenent, Largus T; Mau, Margit; George, Usha; Zahn, James A; Raskin, Lutgarde

    2008-05-01

    An anaerobic sequencing batch reactor (ASBR), seeded with a biomass inoculum that previously had not been exposed to the macrolide antimicrobial tylosin (mixture of Tylosin A, B, C, and D), was operated for 3 months with swine waste without Tylosin A and for 9 months with swine waste containing Tylosin A at an average concentration of 1.6 mg/L. When swine waste with tylosin was fed to the ASBR, methane production and volatile solids removal did not appear to be inhibited and a methane yield of 0.47 L methane per gram volatile solids fed to the ASBR was observed. Throughout the operating period, Tylosin A levels in ASBR biomass and effluent were below the detection limit of 0.01 mg/L. However, during the first 3 months of operation, the levels of macrolide-lincosamide-streptogramin B (MLSB)-resistant bacteria in the ASBR biomass increased substantially as determined by hybridizations with oligonucleotide probes designed to target MLSB-resistant bacteria. Since no Tylosin A was present in the swine waste during the initial 3 months, the presence of MLSB-resistant bacteria in the swine waste was likely the reason for the increase in resistance. Subsequently, the levels of MLSB-resistant bacteria in ASBR biomass stabilized with an average of 44.9% for the 9 months of operation with swine waste containing Tylosin A. The level of MLSB-resistant bacteria in the swine waste fed to the ASBR during this period averaged 18.0%. The results indicate that anaerobic treatment of a waste stream containing tylosin was effective (based on reactor performance) and that the level of resistant bacteria in the ASBR was substantially higher than in the waste stream fed to this system.

  11. Mesophilic and thermophilic anaerobic co-digestion of abattoir wastewater and fruit and vegetable waste in anaerobic sequencing batch reactors.

    Science.gov (United States)

    Bouallagui, Hassib; Rachdi, Boutheina; Gannoun, Hana; Hamdi, Moktar

    2009-06-01

    Anaerobic co-digestion of fruit and vegetable waste (FVW) and abattoir wastewater (AW) was investigated using anaerobic sequencing batch reactors (ASBRs). The effects of hydraulic retention time (HRT) and temperature variations on digesters performances were examined. At both 20 and 10 days biogas production for co-digestion was greater thanks to the improved balance of nutrients. The high specific gas productions for the different digestion processes were 0.56, 0.61 and 0.85 l g(-1) total volatile solids (TVS) removal for digesters treating AW, FVW and AW + FVW, respectively. At an HRT of 20 days, biogas production rates from thermophilic digesters were higher on average than from mesophilic AW, FVW and AW + FVW digestion by 28.5, 44.5 and 25%, respectively. However, at 10 days of HRT results showed a decrease of biogas production rate for AW and AW + FVW digestion processes due to the high amount of free ammonia at high organic loading rate (OLR).

  12. Two-stage anaerobic digestion of biodegradable municipal solid waste using a rotating drum mesh filter bioreactor and anaerobic filter.

    Science.gov (United States)

    Walker, M; Banks, C J; Heaven, S

    2009-09-01

    A rotating drum mesh filter bioreactor (RDMFBR) with a 100 microm mesh coupled to an anaerobic filter was used for the anaerobic digestion of biodegradable municipal solid waste (BMW). Duplicate systems were operated for 72 days at an organic loading rate (OLR) of 7.5 g VS l(-1) d(-1). Early in the experiment most of the methane was produced in the 2nd stage. This situation gradually reversed as methanogenesis became established in the 1st stage digester, which eventually produced 86-87% of the total system methane. The total methane production was 0.2 l g(-1) VS(added) with 60-62% volatile solids destruction. No fouling was experienced during the experiment at a transmembrane flux rate of 3.5 l m(-2) h(-1). The system proved to be robust and stably adjusted to a shock loading increase to 15 g VS l(-1) d(-1), although this reduced the overall methane production to 0.15 l g(-1) VS(added).

  13. Anaerobic waste water purification and biogas production in a pulsed bioreactor. Anaerobe Abwasserreinigung mit Biogasgewinnung in einem gepulsten Bioreaktor

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, K.Y.

    1986-12-18

    The author's experiments were carried out in a novel type of bioreactor. In view of the advantages in the anaerobic process (high concentrations of biomass), the microorganisms were retained inside the bioreactor by fixation on a carrier. To avoid the problems otherwise encountered in bioreactors with fixed bacteria, in the pulsed bioreactor the block of foamed polymer carrying the bacteria is moved upwards and downwards in a single period at longer intervals of time. The reactor geometry and the pulsed movement assure a uniform and strong flow through the carrier material; gas bubbles are quickly removed from the bacterial surfaces and led out of the bioreactor, thus ensuring uniform bacterial supply and discharge. The biochemical conversion rate was determined using a highly burdened liquid filtrate waste. The conversion rate and gas productivity were found to be a function of the time of residue and room burden.

  14. Microalgae Cultivation on Anaerobic Digestate of Municipal Wastewater, Sewage Sludge and Agro-Waste

    Directory of Open Access Journals (Sweden)

    Luca Zuliani

    2016-10-01

    Full Text Available Microalgae are fast-growing photosynthetic organisms which have the potential to be exploited as an alternative source of liquid fuels to meet growing global energy demand. The cultivation of microalgae, however, still needs to be improved in order to reduce the cost of the biomass produced. Among the major costs encountered for algal cultivation are the costs for nutrients such as CO2, nitrogen and phosphorous. In this work, therefore, different microalgal strains were cultivated using as nutrient sources three different anaerobic digestates deriving from municipal wastewater, sewage sludge or agro-waste treatment plants. In particular, anaerobic digestates deriving from agro-waste or sewage sludge treatment induced a more than 300% increase in lipid production per volume in Chlorella vulgaris cultures grown in a closed photobioreactor, and a strong increase in carotenoid accumulation in different microalgae species. Conversely, a digestate originating from a pilot scale anaerobic upflow sludge blanket (UASB was used to increase biomass production when added to an artificial nutrient-supplemented medium. The results herein demonstrate the possibility of improving biomass accumulation or lipid production using different anaerobic digestates.

  15. Methanogenic community composition in an organic waste mixture in an anaerobic bioreactor

    Science.gov (United States)

    Gryta, Agata; Oszust, Karolina; Brzezińska, Małgorzata; Ziemiński, Krzysztof; Bilińska-Wielgus, Nina; Frąc, Magdalena

    2017-07-01

    The aim of the study was to elucidate the substantial relationship between the compositions of methanogen community that assembles in the anaerobic digester mass and link it to methane production activity. The results of the metagenomic studies were used to evaluate how the methanogen structure changes during an anaerobic digestion process under various waste retention times (21, 23, 25, 29, 33, 39, 47 and 61 days). Phylogenetically coherent populations of methanogens were assessed by 16S rRNA gene next-generation sequencing and terminal restriction fragment length polymorphism fingerprinting of a specific molecular marker, the mcrA gene. The results indicated multiple phylogenetically diverse methanogen populations associated with the various steps of anaerobic digestion. The stages of the anaerobic digestion process and waste retention times determine the microbial composition. The most dominant and acclimated microbial communities in all samples belonged to the genera Methanosaeta and Methanobacterium. The methane yield was consistent with the results of the microbial community structure, which indicated that acetotrophic Methanosaeta was the most active and most important during the methanogenic stage.

  16. Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jinming [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zhang, Ruihong; Sun, Huawei [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); El-Mashad, Hamed M. [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Department of Agricultural Engineering, Mansoura University, El-Mansoura (Egypt); Ying, Yibin [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China)

    2008-12-15

    The effect of different food to microorganism ratios (F/M) (1-10) on the hydrogen production from the anaerobic batch fermentation of mixed food waste was studied at two temperatures, 35 {+-} 2 C and 50 {+-} 2 C. Anaerobic sludge taken from anaerobic reactors was used as inoculum. It was found that hydrogen was produced mainly during the first 44 h of fermentation. The F/M between 7 and 10 was found to be appropriate for hydrogen production via thermophilic fermentation with the highest yield of 57 ml-H{sub 2}/g VS at an F/M of 7. Under mesophilic conditions, hydrogen was produced at a lower level and in a narrower range of F/Ms, with the highest yield of 39 ml-H{sub 2}/g VS at the F/M of 6. A modified Gompertz equation adequately (R{sup 2} > 0.946) described the cumulative hydrogen production yields. This study provides a novel strategy for controlling the conditions for production of hydrogen from food waste via anaerobic fermentation. (author)

  17. Comparison of existing models to simulate anaerobic digestion of lipid-rich waste.

    Science.gov (United States)

    Béline, F; Rodriguez-Mendez, R; Girault, R; Bihan, Y Le; Lessard, P

    2017-02-01

    Models for anaerobic digestion of lipid-rich waste taking inhibition into account were reviewed and, if necessary, adjusted to the ADM1 model framework in order to compare them. Experimental data from anaerobic digestion of slaughterhouse waste at an organic loading rate (OLR) ranging from 0.3 to 1.9kgVSm(-3)d(-1) were used to compare and evaluate models. Experimental data obtained at low OLRs were accurately modeled whatever the model thereby validating the stoichiometric parameters used and influent fractionation. However, at higher OLRs, although inhibition parameters were optimized to reduce differences between experimental and simulated data, no model was able to accurately simulate accumulation of substrates and intermediates, mainly due to the wrong simulation of pH. A simulation using pH based on experimental data showed that acetogenesis and methanogenesis were the most sensitive steps to LCFA inhibition and enabled identification of the inhibition parameters of both steps.

  18. Early warning indicators for monitoring the process failure of anaerobic digestion system of food waste.

    Science.gov (United States)

    Li, Lei; He, Qingming; Wei, Yunmei; He, Qin; Peng, Xuya

    2014-11-01

    To determine reliable state parameters which could be used as early warning indicators of process failure due to the acidification of anaerobic digestion of food waste, three mesophilic anaerobic digesters of food waste with different operation conditions were investigated. Such parameters as gas production, methane content, pH, concentrations of volatile fatty acid (VFA), alkalinity and their combined indicators were evaluated. Results revealed that operation conditions significantly affect the responses of parameters and thus the optimal early warning indicators of each reactor differ from each other. None of the single indicators was universally valid for all the systems. The universally valid indicators should combine several parameters to supply complementary information. A combination of total VFA, the ratio of VFA to total alkalinity (VFA/TA) and the ratio of bicarbonate alkalinity to total alkalinity (BA/TA) can reflect the metabolism of the digesting system and realize rapid and effective early warning.

  19. Coupling System for Food Wastes Anaerobic Digestion and Polyhydroxyalkanoates Production with Ralstonia eutropha

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new technology was developed to couple the anaerobic digestion of food wastes with production of polyhydroxyalkanoates (PHAs). Acetic, propionic, butyric and lactic acids were produced during food wastes anaerobic digestion and their concentrations reached 5.5, 1.8, 27.4 and 32.7 g/L, respectively under appropriate digestion conditions. The fermentative acids were transferred through a dialysis membrane to an air-lift reactor for PHA synthesis by Ralstonia eutropha. Dry cell concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The obtained PHA was a copolymer of (-hydroxybutyrate (HB) and (-hydroxyvalerate (HV) with 2.8% (mole ratio) of HV units in polymer.

  20. Anaerobic Codigestion of Sludge: Addition of Butcher's Fat Waste as a Cosubstrate for Increasing Biogas Production.

    Science.gov (United States)

    Martínez, E J; Gil, M V; Fernandez, C; Rosas, J G; Gómez, X

    2016-01-01

    Fat waste discarded from butcheries was used as a cosubstrate in the anaerobic codigestion of sewage sludge (SS). The process was evaluated under mesophilic and thermophilic conditions. The codigestion was successfully attained despite some inhibitory stages initially present that had their origin in the accumulation of volatile fatty acids (VFA) and adsorption of long-chain fatty acids (LCFA). The addition of a fat waste improved digestion stability and increased biogas yields thanks to the higher organic loading rate (OLR) applied to the reactors. However, thermophilic digestion was characterized by an effluent of poor quality and high VFA content. Results from spectroscopic analysis suggested the adsorption of lipid components onto the anaerobic biomass, thus disturbing the complete degradation of substrate during the treatment. The formation of fatty aggregates in the thermophilic reactor prevented process failure by avoiding the exposure of biomass to the toxic effect of high LCFA concentrations.

  1. Enhanced Waste Tank Level Model

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.

    1999-06-24

    'With the increased sensitivity of waste-level measurements in the H-Area Tanks and with periods of isolation, when no mass transfer occurred for certain tanks, waste-level changes have been recorded with are unexplained.'

  2. Enhanced Waste Tank Level Model

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.

    1999-06-24

    'With the increased sensitivity of waste-level measurements in the H-Area Tanks and with periods of isolation, when no mass transfer occurred for certain tanks, waste-level changes have been recorded with are unexplained.'

  3. The physicochemical characteristics and anaerobic degradability of desiccated coconut industry waste water.

    Science.gov (United States)

    Chanakya, H N; Khuntia, Himanshu Kumar; Mukherjee, Niranjan; Aniruddha, R; Mudakavi, J R; Thimmaraju, Preeti

    2015-12-01

    Desiccated coconut industries (DCI) create various intermediates from fresh coconut kernel for cosmetic, pharmaceutical and food industries. The mechanized and non-mechanized DCI process between 10,000 and 100,000 nuts/day to discharge 6-150 m(3) of malodorous waste water leading to a discharge of 264-6642 kg chemical oxygen demand (COD) daily. In these units, three main types of waste water streams are coconut kernel water, kernel wash water and virgin oil waste water. The effluent streams contain lipids (1-55 g/l), suspended solids (6-80 g/l) and volatile fatty acids (VFA) at concentrations that are inhibitory to anaerobic bacteria. Coconut water contributes to 20-50% of the total volume and 50-60% of the total organic loads and causes higher inhibition of anaerobic bacteria with an initial lag phase of 30 days. The lagooning method of treatment widely adopted failed to appreciably treat the waste water and often led to the accumulation of volatile fatty acids (propionic acid) along with long-chain unsaturated free fatty acids. Biogas generation during biological methane potential (BMP) assay required a 15-day adaptation time, and gas production occurred at low concentrations of coconut water while the other two streams did not appear to be inhibitory. The anaerobic bacteria can mineralize coconut lipids at concentrations of 175 mg/l; however; they are severely inhibited at a lipid level of ≥350 mg/g bacterial inoculum. The modified Gompertz model showed a good fit with the BMP data with a simple sigmoid pattern. However, it failed to fit experimental BMP data either possessing a longer lag phase and/or diauxic biogas production suggesting inhibition of anaerobic bacteria.

  4. Monitoring the anaerobic treatment of waste waters; Control en la depuracion anaerobia de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Leon de Mora, C.; Molina Cantero, F.J.; Romero Galey, F.J.; Gomez Banderas, J.M. [Dpto. Tecnologia Electronica. Esc. Univ. Politec. Sevilla, Sevilla, (Spain)

    1997-04-01

    This article describes the results obtained in developing a system for monitoring sewage treatment. The system, supported by a PC, includes a fuzzy logic control algorithm for monitoring the anaerobic treatment of waste waters on the basis of data from sensors attached to an industrial robot (PLC). Its most outstanding features is that it is also capable of evaluating new monitoring strategies using parameters not originally included. (Author) 6 refs.

  5. Comprehensive Assessment of Hormones, Phytoestrogens, and Estrogenic Activity in an Anaerobic Swine Waste Lagoon

    OpenAIRE

    Yost, Erin E.; Meyer, Michael T.; Dietze, Julie E.; Meissner, Benjamin M.; Worley-Davis, Lynn; Williams, C. Michael; Lee, Boknam; Kullman, Seth W.

    2013-01-01

    In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were ...

  6. Fast characterization of solid organic waste content with near infrared spectroscopy in anaerobic digestion.

    Science.gov (United States)

    Charnier, Cyrille; Latrille, Eric; Jimenez, Julie; Lemoine, Margaux; Boulet, Jean-Claude; Miroux, Jérémie; Steyer, Jean-Philippe

    2017-01-01

    The development of anaerobic digestion involves both co-digestion of solid wastes and optimization of the feeding recipe. Within this context, substrate characterisation is an essential issue. Although it is widely used, the biochemical methane potential is not sufficient to optimize the operation of anaerobic digestion plants. Indeed the biochemical composition in carbohydrates, lipids, proteins and the chemical oxygen demand of the inputs are key parameters for the optimisation of process performances. Here we used near infrared spectroscopy as a robust and less-time consuming tool to predict the solid waste content in carbohydrates, lipids and nitrogen, and the chemical oxygen demand. We built a Partial Least Square regression model with 295 samples and validated it with an independent set of 46 samples across a wide range of solid wastes found in anaerobic digestion units. The standard errors of cross-validation were 90mgO2⋅gTS(-1) carbohydrates, 2.5∗10(-2)g⋅gTS(-1) lipids, 7.2∗10(-3)g⋅gTS(-1) nitrogen and 99mgO2⋅gTS(-1) chemical oxygen demand. The standard errors of prediction were 53mgO2⋅gTS(-1) carbohydrates, 3.2∗10(-2)g⋅gTS(-1) lipids, 8.6∗10(-3)g⋅gTS(-1) nitrogen and 83mgO2⋅gTS(-1) chemical oxygen demand. These results show that near infrared spectroscopy is a new fast and cost-efficient way to characterize solid wastes content and improve their anaerobic digestion monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Efficiency of the anaerobic treatment of the organic fraction of municipal solid waste: collection and pretreatment

    DEFF Research Database (Denmark)

    Hartmann, Hinrich; Møller, H.B.; Ahring, Birgitte Kiær

    2004-01-01

    plants where OFMSW is treated and the municipality staff responsible for waste management. With the aim of fulfilling the governmental goal to treat 150 000 tons of OFMSW by the year 2004 mainly by anaerobic digestion, the different municipalities are investigating different concepts of waste collection...... and treatment. The quality of the OFMSW treated is the key to smooth operation of the biogas process including a high biogas yield and production of an effluent that is feasible for use as fertilizer on agricultural land. Comparison of the different concepts leads to the conclusion that source-sorting of OFMSW...

  8. Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2006-01-01

    Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics......-stage systems show in some investigations a higher reduction of recalcitrant organic matter compared to single-stage systems, but they are seldom applied in full-scale. An extended cost benefit calculation shows that the highest overall benefit of the process is achieved at an OLR that is lower and a hydraulic...

  9. Biogas production from anaerobic digestion of food waste and relevant air quality implications.

    Science.gov (United States)

    Kuo, Jeff; Dow, Jason

    2017-09-01

    Biopower can diversify energy supply and improve energy resiliency. Increases in biopower production from sustainable biomass can provide many economic and environmental benefits. For example, increasing biogas production through anaerobic digestion of food waste would increase the use of renewable fuels throughout California and add to its renewables portfolio. Although a biopower project will produce renewable energy, the process of producing bioenergy should harmonize with the goal of protecting public health. Meeting air emission requirements is paramount to the successful implementation of any biopower project. A case study was conducted by collecting field data from a wastewater treatment plant that employs anaerobic codigestion of fats, oils, and grease (FOG), food waste, and wastewater sludge, and also uses an internal combustion (IC) engine to generate biopower using the biogas. This research project generated scientific information on (a) quality and quantity of biogas from anaerobic codigestion of food waste and municipal wastewater sludge, (b) levels of contaminants in raw biogas that may affect beneficial uses of the biogas, (c) removal of the contaminants by the biogas conditioning systems, (d) emissions of NOx, SO2, CO, CO2, and methane, and (e) types and levels of air toxics present in the exhausts of the IC engine fueled by the biogas. The information is valuable to those who consider similar operations (i.e., co-digestion of food waste with municipal wastewater sludge and power generation using the produced biogas) and to support rulemaking decisions with regards to air quality issues for such applications. Full-scale operation of anaerobic codigestion of food waste with municipal sludge is viable, but it is still new. There is a lack of readily available scientific information on the quality of raw biogas, as well as on potential emissions from power generation using this biogas. This research developed scientific information with regard to

  10. Gas production in anaerobic dark-fermentation processes from agriculture solid waste

    Science.gov (United States)

    Sriwuryandari, L.; Priantoro, E. A.; Sintawardani, N.

    2017-03-01

    Approximately, Bandung produces agricultural solid waste of 1549 ton/day. This wastes consist of wet-organic matter and can be used for bio-gas production. The research aimed to apply the available agricultural solid waste for bio-hydrogen. Biogas production was done by a serial of batches anaerobic fermentation using mix-culture bacteria as the active microorganism. Fermentation was carried out inside a 30 L bioreactor at room temperature. The analyzed parameters were of pH, total gas, temperature, and COD. Result showed that from 3 kg/day of organic wastes, various total gases of O2, CH4, H2, CO2, and CnHn,O2 was produced.

  11. Production of Biogas through Anaerobic Cofermentation of Cattle Slurry with Biscuit Waste

    Directory of Open Access Journals (Sweden)

    Chamrádová K.

    2016-03-01

    Full Text Available The paper presents the results of the model of anaerobic co-fermentation of cattle slurry with biscuit waste. It was confirmed that the waste from the food industry is a valuable biogas substrate. The highest specific production of methane (0.49 mN3·kgVS-1 was achieved in the co-fermentation of 20 wt% biscuit waste with cattle slurry. The feed mixture contained 22 wt% of total solids. The biscuit waste has the specific production of biogas 0.66 mN 3·kg-1 and the specific production of methane 0.38 mN 3·kg-1.

  12. Enhancement of anaerobic hydrogen production by iron and nickel

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Dogan; Puhakka, Jaakko A. [Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere (Finland)

    2010-08-15

    The effects of iron and nickel on hydrogen (H{sub 2}) production were investigated in a glucose-fed anaerobic Continuous Flow Stirred Tank Reactor (ACSTR). Both iron and nickel improved the reactor performance and H{sub 2} production was enhanced by 71% with the sole iron or nickel supplementation. In all cases, H{sub 2} production yield was increased by lowering both ethanol and total metabolites production and increasing butyrate production. Furthermore, iron and nickel slightly increased biomass production while glucose degradation decreased with the supplementation of nickel. Dynamic changes in bacterial composition as analyzed by 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) revealed that hydrogen was produced mainly by Clostridium butyricum strains and that nickel addition decreased the microbial diversity. (author)

  13. Comparative evaluation of anaerobic digestion for sewage sludge and various organic wastes with simple modeling.

    Science.gov (United States)

    Hidaka, Taira; Wang, Feng; Tsumori, Jun

    2015-09-01

    Anaerobic co-digestion of sewage sludge and other organic wastes, such as kitchen garbage, food waste, and agricultural waste, at a wastewater treatment plant (WWTP) is a promising method for both energy and material recovery. Substrate characteristics and the anaerobic digestion performance of sewage sludge and various organic wastes were compared using experiments and modeling. Co-digestion improved the value of digested sewage sludge as a fertilizer. The relationship between total and soluble elemental concentrations was correlated with the periodic table: most Na and K (alkali metals) were soluble, and around 20-40% of Mg and around 10-20% of Ca (alkaline earth metals) were soluble. The ratio of biodegradable chemical oxygen demand of organic wastes was 65-90%. The methane conversion ratio and methane production rate under mesophilic conditions were evaluated using a simplified mathematical model. There was reasonably close agreement between the model simulations and the experimental results in terms of methane production and nitrogen concentration. These results provide valuable information and indicate that the model can be used as a pre-evaluation tool to facilitate the introduction of co-digestion at WWTPs.

  14. Evaluation of single vs. staged mesophilic anaerobic digestion of kitchen waste with and without microwave pretreatment.

    Science.gov (United States)

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin

    2013-08-15

    Effects of single and dual stage (acidogenic-methanogenic) mesophilic anaerobic digestion (AD) of kitchen waste (KW) was evaluated at hydraulic retention times (HRTs) of 20, 15, 12 and 9 d with and without thermal microwave (MW) pretreatment (145 °C). Anaerobic acidification in terms of acid accumulation was superior compared to microaerophilic acidification. Maximum anaerobic acidification of KW was determined to occur with an HRT of 2 d which was then selected for the acidification stage. The dual stage AD system fed with untreated KW produced the maximum biogas and volatile solids (VS) stabilization efficiencies at the shortest HRT of 9 d. Conversely, for free liquid resulting from MW pretreatment of KW the two stage reactor at 20 d HRT produced three fold more methane compared with the untreated free liquid control. However, MW pretreatment and AD of the free liquid fraction only, was not a sustainable treatment option. For KW, staging of the AD process had a greater positive impact on waste stabilization and methane yield compared to single stage reactors or MW pretreatment. KW can be characterized as being a readily biodegradable solid waste; concomitantly it is recommended that digester staging without MW pretreatment be employed to maximize methane yield and production.

  15. Anaerobic codigestion of dairy manure and food manufacturing waste for renewable energy generation in New York State

    Science.gov (United States)

    Rankin, Matthew J.

    Anaerobic digestion is a microbiological process that converts biodegradable organic material into biogas, consisting primarily of methane and carbon dioxide. Anaerobic digestion technologies have been integrated into wastewater treatment facilities nationwide for many decades to increase the economic viability of the treatment process by converting a waste stream into two valuable products: biogas and fertilizer. Thus, anaerobic digestion offers potential economic and environmental benefits of organic waste diversion and renewable energy generation. The use of biogas has many applications, including cogeneration, direct combustion, upgrading for conversion to feed a fuel cell, and compression for injection into the natural gas grid or for vehicular use. The potential benefits of waste diversion and renewable energy generation are now being realized by major organic waste generators in New York State, in particular the food manufacturing and dairy industries, thus warranting an analysis of the energy generation potential for these waste products. Anaerobic codigestion of dairy manure and food-based feedstocks reflects a cradle-to- cradle approach to organic waste management. Given both of their abundance throughout New York State, waste-to-energy processes represent promising waste management strategies. The objective of this thesis was to evaluate the current technical and economic feasibility of anaerobically codigesting existing dairy manure and food manufacturing waste feedstocks in New York State to produce high quality biogas for renewable energy generation. The first element to determining the technical feasibility of anaerobic codigestion potential in New York State was to first understand the feedstock availability. A comprehensive survey of existing organic waste streams was conducted. The key objective was to identify the volume and composition of dairy manure and liquid-phase food manufacturing waste streams available in New York State to make

  16. Microbial network for waste activated sludge cascade utilization in an integrated system of microbial electrolysis and anaerobic fermentation

    DEFF Research Database (Denmark)

    Liu, Wenzong; He, Zhangwei; Yang, Chunxue

    2016-01-01

    and Parabacteroides, which showed a delayed contribution to the extracellular electron transport leading to a slow cascade utilization of WAS. Conclusions: Efficient pretreatment could supply more short-chain fatty acids and higher conductivities in the fermentative liquid, which facilitated mass transfer in anodic......Background: Bioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved...... in an integrated system of microbial electrolysis cell (MEC) and anaerobic digestion (AD) for waste activated sludge (WAS). Microbial communities in integrated system would build a thorough energetic and metabolic interaction network regarding fermentation communities and electrode respiring communities...

  17. A novel approach of anaerobic co-digestion between organic fraction of food waste and waste sludge from municipal wastewater treatment plant: Effect of mixing ratio

    Science.gov (United States)

    Nga, Dinh Thi; Ngoc, Tran Thi Minh; Van Ty, Nguyen; Thuan, Van Tan

    2017-09-01

    The aim of this study was to investigate the effect of mixing ratio of co-anaerobic digestion between dewatered waste sludge from municipal wastewater treatment plant (DS) and organic fraction of food waste (FW). The experiment was carried out in 3L reactors for 16 days at ambient temperature. Four mixing ratios of DW and FW was investigated including 100 % DS : 0 % FW (Run S100); 75% DS : 25 % FW (Run S75); 50% DS : 50% FW (Run S50); and 25% DS : 75% FW (Run S25) in term of VS concentration. As a result, the Run S50 achieved best performance among the four funs indicated in biogas accumulation of 32.48 L biogas and methane yield of 358.9 400ml CH4/g VS removal after 16 days operation at ambient temperature. Biogas accumulation of Run S25 was higher than that of Run S75. Run S100 produced the lowest of biogas of all runs. It is concluded that co-anaerobic digestion of different organic sources could enhance the performance of methane fermentation.

  18. Waste to Energy Potential - A High Concentration Anaerobic Bioreactor

    Science.gov (United States)

    2012-05-23

    REPORT DATE 23 MAY 2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Waste to Energy Potential - A High...and fermentative bacteria break down organic carbon to VFAs Acetogens break down VFAs to CH3CO2 − and H2 + Acetoclastic methanogens break...s -999999 999999 7 481 su -999999 999999 0 .. -999999 999999 HCA8 pti Flo$&-tdgc Tan.\\ feed su -999999 999999 0 .. -999999 999999 A-l>o -999999

  19. Upgrading of the anaerobic digestion of waste activated sludge by combining temperature-phased anaerobic digestion and intermediate ozonation.

    Science.gov (United States)

    Kobayashi, T; Li, Y Y; Harada, H; Yasui, H; Noike, T

    2009-01-01

    Upgrading of the anaerobic digestion of waste activated sludge (WAS) by the combination of temperature-phased two-stage digestion and intermediate ozonation was investigated by a continuous experiment with two processes, TM and TOM. The TM process is a temperature-phased two-stage system, which consists of a thermophilic digester and a mesophilic digester in series. The TOM process is a temperature-phased two-stage process with the intermediate ozonation. Two processes were operated at hydraulic retention times of 30 days for over 123 days. Waste activated sludge taken from wastewater treatment plant was fed as a substrate. Microbial community structure in each digester was analysed with molecular tools. Despite of less amount of ozone dose in TOM than ozone pre-treatment process, better effect of ozonation on performance improvement was obtained in TOM. TOM had the highest methane yield and COD(Cr) reduction among comparative processes. Furthermore, flocculation efficiency of TOM followed that of mesophilic digestion. Quality of dewatered supernatant is comparable to mesophilic digestion.

  20. High-rate iron-rich activated sludge as stabilizing agent for the anaerobic digestion of kitchen waste.

    Science.gov (United States)

    De Vrieze, Jo; De Lathouwer, Lars; Verstraete, Willy; Boon, Nico

    2013-07-01

    Anaerobic digestion is a key technology in the bio-based economy and can be applied to convert a wide range of organic substrates into CH4 and CO2. Kitchen waste is a valuable substrate for anaerobic digestion, since it is an abundant source of organic matter. Yet, digestion of single kitchen waste often results in process failure. High-rate activated sludge or A-sludge is produced during the highly loaded first stage of the two-phase 'Adsorptions-Belebungsverfahren' or A/B activated sludge system for municipal wastewater treatment. In this specific case, the A-sludge was amended with FeSO4 to enhance phosphorous removal and coagulation during the water treatment step. This study therefore evaluated whether this Fe-rich A-sludge could be used to obtain stable methanation and higher methane production values during co-digestion with kitchen waste. It was revealed that Fe-rich A-sludge can be a suitable co-substrate for kitchen waste; i.e. methane production rate values of 1.15 ± 0.22 and 1.12 ± 0.28 L L(-1) d(-1) were obtained during mesophilic and thermophilic co-digestion respectively of a feed-mixture consisting of 15% KW and 85% A-sludge. The thermophilic process led to higher residual VFA concentrations, up to 2070 mg COD L(-1), and can therefore be considered less stable. Addition of micro- and macronutrients provided a more stable digestion of single kitchen waste, i.e. a methane production of 0.45 L L(-1) d(-1) was obtained in the micronutrient treatment compared to 0.30 L L(-1) d(-1) in the control treatment on day 61. Yet, methane production during single kitchen waste digestion still decreased toward the end of the experiment, despite the addition of micronutrients. Methane production rates were clearly influenced by the total numbers of archaea in the different reactors. This study showed that Fe-rich A-sludge and kitchen waste are suitable for co-digestion.

  1. Effect of domestication on microorganism diversity and anaerobic digestion of food waste.

    Science.gov (United States)

    Bi, S J; Hong, X J; Wang, G X; Li, Y; Gao, Y M; Yan, L; Wang, Y J; Wang, W D

    2016-08-19

    To accomplish the rapid start-up and stable operation of biogas digesters, an efficient inoculum is required. To obtain such an inoculum for food waste anaerobic digestion, we domesticated dairy manure anaerobic digestion residue by adding food waste every day. After 36 days, the pH and biogas yield stabilized signifying the completion of domestication. During domestication, the microbial communities in the inocula were investigated by constructing 16S rDNA clone libraries. We evaluated the effect of the domesticated inoculum by testing batch food waste anaerobic digestion with a non-domesticated inoculum as a control. The pH and methane yield of the digestion systems were determined as measurement indices. Domestication changed the composition and proportion of bacteria and archaea in the inocula. Of the bacteria, Clostridia (49.3%), Bacteroidales (19.5%), and Anaerolinaceae (8.1%) species were dominant in the seed sludge; Anaerolinaceae (49.0%), Clostridia (28.4%), and Bacteroidales (9.1%), in domestication sludge. Methanosaeta was the dominant genus in both of the seed (94.3%) and domestication (74.3%) sludge. However, the diversity of methanogenic archaea was higher in the domestication than in seed sludge. Methanoculleus, which was absent from the seed sludge, appeared in the domestication sludge (21.7%). When the domesticated inoculum was used, the digestion system worked stably (organic loading rate: 20 gVS/L; methane yield: 292.2 ± 9.8 mL/gVS; VS = volatile solids), whereas the digestion system inoculated with seed sludge failed to generate biogas. The results indicate that inoculum domestication ensures efficient and stable anaerobic digestion by enriching the methanogenic strains.

  2. Enhancing anaerobic digestion of poultry blood using activated carbon

    Directory of Open Access Journals (Sweden)

    Maria José Cuetos

    2017-05-01

    Full Text Available The potential of using anaerobic digestion for the treatment of poultry blood has been evaluated in batch assays at the laboratory scale and in a mesophilic semi-continuous reactor. The biodegradability test performed on residual poultry blood was carried out in spite of high inhibitory levels of acid intermediaries. The use of activated carbon as a way to prevent inhibitory conditions demonstrated the feasibility of attaining anaerobic digestion under extreme ammonium and acid conditions. Batch assays with higher carbon content presented higher methane production rates, although the difference in the final cumulative biogas production was not as sharp. The digestion of residual blood was also studied under semi-continuous operation using granular and powdered activated carbon. The average specific methane production was 216 ± 12 mL CH4/g VS. This result was obtained in spite of a strong volatile fatty acid (VFA accumulation, reaching values around 6 g/L, along with high ammonium concentrations (in the range of 6–8 g/L. The use of powdered activated carbon resulted in a better assimilation of C3-C5 acid forms, indicating that an enhancement in syntrophic metabolism may have taken place. Thermal analysis and scanning electron microscopy (SEM were applied as analytical tools for measuring the presence of organic material in the final digestate and evidencing modifications on the carbon surface. The addition of activated carbon for the digestion of residual blood highly improved the digestion process. The adsorption capacity of ammonium, the protection this carrier may offer by limiting mass transfer of toxic compounds, and its capacity to act as a conductive material may explain the successful digestion of residual blood as the sole substrate.

  3. Enhancing anaerobic digestion of poultry blood using activated carbon.

    Science.gov (United States)

    Cuetos, Maria José; Martinez, E Judith; Moreno, Rubén; Gonzalez, Rubén; Otero, Marta; Gomez, Xiomar

    2017-05-01

    The potential of using anaerobic digestion for the treatment of poultry blood has been evaluated in batch assays at the laboratory scale and in a mesophilic semi-continuous reactor. The biodegradability test performed on residual poultry blood was carried out in spite of high inhibitory levels of acid intermediaries. The use of activated carbon as a way to prevent inhibitory conditions demonstrated the feasibility of attaining anaerobic digestion under extreme ammonium and acid conditions. Batch assays with higher carbon content presented higher methane production rates, although the difference in the final cumulative biogas production was not as sharp. The digestion of residual blood was also studied under semi-continuous operation using granular and powdered activated carbon. The average specific methane production was 216 ± 12 mL CH4/g VS. This result was obtained in spite of a strong volatile fatty acid (VFA) accumulation, reaching values around 6 g/L, along with high ammonium concentrations (in the range of 6-8 g/L). The use of powdered activated carbon resulted in a better assimilation of C3-C5 acid forms, indicating that an enhancement in syntrophic metabolism may have taken place. Thermal analysis and scanning electron microscopy (SEM) were applied as analytical tools for measuring the presence of organic material in the final digestate and evidencing modifications on the carbon surface. The addition of activated carbon for the digestion of residual blood highly improved the digestion process. The adsorption capacity of ammonium, the protection this carrier may offer by limiting mass transfer of toxic compounds, and its capacity to act as a conductive material may explain the successful digestion of residual blood as the sole substrate.

  4. Solid state anaerobic co-digestion of yard waste and food waste for biogas production.

    Science.gov (United States)

    Brown, Dan; Li, Yebo

    2013-01-01

    Food and yard wastes are available year round at low cost and have the potential to complement each other for SS-AD. The goal of this study was to determine optimal feedstock/effluent (F/E) and food waste/yard waste mixing ratios for optimal biogas production. Co-digestion of yard and food waste was carried out at F/E ratios of 1, 2, and 3. For each F/E ratio, food waste percentages of 0%, 10%, and 20%, based on dry volatile solids, were evaluated. Results showed increased methane yields and volumetric productivities as the percentage of food waste was increased to 10% and 20% of the substrate at F/E ratios of 2 and 1, respectively. This study showed that co-digestion of food waste with yard waste at specific ratios can improve digester operating characteristics and end performance metrics over SS-AD of yard waste alone.

  5. Methane production enhancement by an independent cathode in integrated anaerobic reactor with microbial electrolysis.

    Science.gov (United States)

    Cai, Weiwei; Han, Tingting; Guo, Zechong; Varrone, Cristiano; Wang, Aijie; Liu, Wenzong

    2016-05-01

    Anaerobic digestion (AD) represents a potential way to achieve energy recovery from waste organics. In this study, a novel bioelectrochemically-assisted anaerobic reactor is assembled by two AD systems separated by anion exchange membrane, with the cathode placing in the inside cylinder (cathodic AD) and the anode on the outside cylinder (anodic AD). In cathodic AD, average methane production rate goes up to 0.070 mL CH4/mL reactor/day, which is 2.59 times higher than AD control reactor (0.027 m(3) CH4/m(3)/d). And COD removal is increased ∼15% over AD control. When changing to sludge fermentation liquid, methane production rate has been further increased to 0.247 mL CH4/mL reactor/day (increased by 51.53% comparing with AD control). Energy recovery efficiency presents profitable gains, and economic revenue from increased methane totally self-cover the cost of input electricity. The study indicates that cathodic AD could cost-effectively enhance methane production rate and degradation of glucose and fermentative liquid.

  6. Influence of transitional states on the microbial ecology of anaerobic digesters treating solid wastes.

    Science.gov (United States)

    Regueiro, Leticia; Veiga, Patricia; Figueroa, Mónica; Lema, Juan M; Carballa, Marta

    2014-03-01

    A better understanding of the microbial ecology of anaerobic processes during transitional states is important to achieve a long-term efficient reactor operation. Five wastes (pig manure, biodiesel residues, ethanol stillage, molasses residues, and fish canning waste) were treated in five anaerobic reactors under the same operational conditions. The influence of the type of substrate and the effect of modifying feeding composition on the microbial community structure was evaluated. The highest biomethanation efficiency was observed in reactors fed with fish canning waste, which also presented the highest active archaeal population and the most diverse microbial communities. Only two Bacteria populations could be directly related to a particular substrate: Ilyobacter with biodiesel residues and Trichococcus with molasses residues. Results showed that the time to achieve steady-state performance after these transitional states was not dependent on the substrate treated. But reactors needed more time to handle the stress conditions derived from the start-up compared to the adaptation to a new feeding. Cluster analyses showed that the type of substrate had a clear influence on the microbiology of the reactors, and that segregation was related to the reactors performance. Finally, we conclude that the previous inoculum history treating solid waste and higher values of active Archaea population are important factors to face a successful change in substrate not entailing stability failure.

  7. An integrated approach to energy recovery from biomass and waste: Anaerobic digestion-gasification-water treatment.

    Science.gov (United States)

    Milani, M; Montorsi, L; Stefani, M

    2014-07-01

    The article investigates the performance of an integrated system for the energy recovery from biomass and waste based on anaerobic digestion, gasification and water treatment. In the proposed system, the organic fraction of waste of the digestible biomass is fed into an anaerobic digester, while a part of the combustible fraction of the municipal solid waste is gasified. Thus, the obtained biogas and syngas are used as a fuel for running a cogeneration system based on an internal combustion engine to produce electric and thermal power. The waste water produced by the integrated plant is recovered by means of both forward and inverse osmosis. The different processes, as well as the main components of the system, are modelled by means of a lumped and distributed parameter approach and the main outputs of the integrated plant such as the electric and thermal power and the amount of purified water are calculated. Finally, the implementation of the proposed system is evaluated for urban areas with a different number of inhabitants and the relating performance is estimated in terms of the main outputs of the system.

  8. Fermentative Hydrogen Production from Combination of Tofu processing and anaerobic digester sludge wastes using a microbial consortium

    Energy Technology Data Exchange (ETDEWEB)

    You-Kwan, O.; Mi-Sun, K.

    2009-07-01

    The combination of Tofu manufacturing waste and anaerobic digester sludge was studied for fermentative H{sub 2} production in batch and continuous modes using a mixed culture originated from sewage. In order to increase the solubilization of organic substrates from Tofu waste, various pretreatments including heat-treatment, acid/alkali treatment, and sonication were examined alone or in combination with others. (Author)

  9. Anaerobic digestion of wastewater screenings for resource recovery and waste reduction

    Science.gov (United States)

    Wid, N.; Horan, N. J.

    2016-06-01

    Wastewater screenings are produced during the first stage of the wastewater treatment process and at present are disposed of to landfill. This material may not only cause operational failure to the treatment system, but also lead to environmental problems. In view of the high organic content of screenings, anaerobic digestion method may not only offer the potential for energy recovery, but also nutrient. In this study the, anaerobic batch digestion was performed at different dry solids concentrations of screenings to study the potential of biogas and phosphorus recovery. The tests demonstrated wastewater screenings were amenable to anaerobic digestion with methane yield was 355 m3/kg VS, which are comparable to the previous results. The digestate was high in P content and can be recovered up to 41%. This study also shows that anaerobic digestion was not only to turn this waste into useful resources, but also has a potential in reducing the organic content up to 31% for safe disposal. In this way the amount of wastewater screenings going to landfill is not only can be reduced, but also valuable products such as methane and phosphorus can also be recovered.

  10. Effect of dietary arsonic acids on performance characteristics of swine waste anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Brumm, M.C.; Sutton, A.L.; Jones, D.D.

    1980-01-01

    A completely random design experiment was conducted to determine the effect of dietary arsonic acids on the performance of laboratory swine waste anaerobic digesters. Fortified corn-soybean meal diets containing no arsonic acids (control), 100 ppm arsanilic acid or 75 ppm roxarsone were fed to growing-finishing pigs. Fresh waste (including urine) from all treatments were collected daily for 74 days and loaded at a rate of 2.4 kg volatile solids/cubic meter into nine 25-L anaerobic digesters heated to 34 degrees with continuous agitation and total gas collection. After a 60-day acclimation period, daily gas production and composition and nutrient composition data were obtained from the anaerobic digesters. Inclusion of the arsonic acids in swine diets reduced dry matter and volatile solids content. Dietary arsonic acids also increased NH4+-N. Alky. was high in all the digesters; however, arsonic acids decreased alky. Dietary arsonic acids reduced the ratio of CH4 to CO2 in the gas compared to the control. Significant amounts of As accumulated in the digesters. Alcohol, ethanol, and propanol concentrations were increased by roxarsone, and arsanilic acid increased the PrCO2H concentrations over the percentage in both the roxarsone and control digesters.

  11. Microbial community structure and dynamics during anaerobic digestion of various agricultural waste materials.

    Science.gov (United States)

    Ziganshin, Ayrat M; Liebetrau, Jan; Pröter, Jürgen; Kleinsteuber, Sabine

    2013-06-01

    The influence of the feedstock type on the microbial communities involved in anaerobic digestion was investigated in laboratory-scale biogas reactors fed with different agricultural waste materials. Community composition and dynamics over 2 months of reactors' operation were investigated by amplicon sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Major bacterial taxa belonged to the Clostridia and Bacteroidetes, whereas the archaeal community was dominated by methanogenic archaea of the orders Methanomicrobiales and Methanosarcinales. Correlation analysis revealed that the community composition was mainly influenced by the feedstock type with the exception of a temperature shift from 38 to 55 °C which caused the most pronounced community shifts. Bacterial communities involved in the anaerobic digestion of conventional substrates such as maize silage combined with cattle manure were relatively stable and similar to each other. In contrast, special waste materials such as chicken manure or Jatropha press cake were digested by very distinct and less diverse communities, indicating partial ammonia inhibition or the influence of other inhibiting factors. Anaerobic digestion of chicken manure relied on syntrophic acetate oxidation as the dominant acetate-consuming process due to the inhibition of aceticlastic methanogenesis. Jatropha as substrate led to the enrichment of fiber-degrading specialists belonging to the genera Actinomyces and Fibrobacter.

  12. Life cycle assessment of energy from waste via anaerobic digestion: a UK case study.

    Science.gov (United States)

    Evangelisti, Sara; Lettieri, Paola; Borello, Domenico; Clift, Roland

    2014-01-01

    Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO2 and total SO2 saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2006-01-01

    Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics...... such as composition of biodegradable fractions, C:N ratio and particle size is described. Generally, source sorting of OFMSW and a high content of food waste leads to higher biogas yields than the use of mechanically sorted OFMSW. Thermophilic processes are more efficient than mesophilic processes in terms of higher......-stage systems show in some investigations a higher reduction of recalcitrant organic matter compared to single-stage systems, but they are seldom applied in full-scale. An extended cost benefit calculation shows that the highest overall benefit of the process is achieved at an OLR that is lower and a hydraulic...

  14. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste.

    Science.gov (United States)

    Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

    2014-02-01

    Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  15. Anaerobic co-digestion of kitchen waste and pig manure with different mixing ratios.

    Science.gov (United States)

    Tian, Hailin; Duan, Na; Lin, Cong; Li, Xue; Zhong, Mingzhu

    2015-07-01

    Anaerobic co-digestion of kitchen waste (KW) and pig manure (PM) with seven different PM to KW total solids (TS) ratios of 1:0, 5:1, 3:1, 1:1, 1:3, 1:5 and 0:1 was conducted at mesophilic temperature (35 ± 1 °C) to investigate the feasibility and process performance. The co-digestion of PM and KW was found to be an available way to enhance methane production compared with solo-digestion of PM or KW. The ratio of PM to KW of 1:1 got the highest biodegradability (BDA) of 85.03% and a methane yield of 409.5 mL/gVS. For the co-digestion of KW and PM, there was no obvious inhibition of ammonia nitrogen because it was in an acceptable range from 1380 mg/L to 2020 mg/L in the whole process. However, severe methane inhibition and long lag phase due to the accumulation of volatile fatty acids (VFAs) was observed while the KW content was over 50%, and in the lag phase, propionic acid and butyric acid made up the major constituents of the total VFAs. The technical digestion time (T80: the time it takes to produce 80% of the digester's maximum gas production) of the above 7 ratios was 15, 21, 22, 27, 49, 62 and 61 days, respectively. In this study, a mixing ratio of 1:1 for PM and KW was found to maximize BDA and methane yield, provided a short digestion time and stable digestion performance and was therefore recommended for further study and engineering application.

  16. Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

    Energy Technology Data Exchange (ETDEWEB)

    García-Gen, Santiago [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Sousbie, Philippe; Rangaraj, Ganesh [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lema, Juan M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Rodríguez, Jorge, E-mail: jrodriguez@masdar.ac.ae [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Institute Centre for Water and Environment (iWater), Masdar Institute of Science and Technology, PO Box 54224 Abu Dhabi (United Arab Emirates); Steyer, Jean-Philippe; Torrijos, Michel [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2015-01-15

    Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.

  17. The Addition of Hatchery Liquid Waste to Dairy Manure Improves Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    WRT Lopes

    Full Text Available ABSTRACT The objective of this study was to determine the optimal inclusion level of liquid egg hatchery waste for the anaerobic co-digestion of dairy cattle manure. A completely randomized experimental was applied, with seven treatments (liquid hatchery waste to cattle manure ratios of0: 100, 5:95, 10:90, 15:85, 20:80, 25:75 and 30:70, with five replicates (batch digester model each. The evaluated variables were disappearance of total solids (TS, volatile solids (VS, and neutral detergent fiber (NDF, and specific production of biogas and of methane. Maximum TS and VS disappearance of 41.3% and 49.6%, were obtained at 15.5% and 16.0% liquid hatchery waste inclusion levels. The addition of 22.3% liquid hatchery considerably reduced NDF substrate content (53.2%. Maximum specific biogas production was obtained with 17% liquid hatchery waste, with the addition of 181.7 and 229.5 L kg-1TS and VS, respectively. The highest methane production, at 120.1 and 151.8 L CH4 kg-1TS and VS, was obtained with the inclusion of 17.5 and 18.0% liquid hatchery waste, respectively. The addition of liquid hatchery waste atratios of up to 15.5%in co-digestion with cattle manure reduced solid and fiber levels in the effluent, and improved biogas and methane production.

  18. Influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions ofS.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 ℃) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation;(3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.

  19. Anaerobic co-digestion of biodiesel waste glycerin with municipal wastewater sludge: microbial community structure dynamics and reactor performance.

    Science.gov (United States)

    Razaviarani, Vahid; Buchanan, Ian D

    2015-04-01

    Two 10 L completely mixed reactors operating at 37°C and 20 days SRT were used to evaluate the relationships between reactor performance and microbial community dynamics during anaerobic co-digestion of biodiesel waste glycerin (BWG) with municipal wastewater sludge (MWS). The addition of up to 1.35% (v/v) BWG to reactor feeds yielded increased VS and COD removal together with enhanced the biogas production and methane yield. This represented 50% of the MWS feed COD. Pyrosequencing analysis showed Methanosaeta (acetoclastic) and Methanomicrobium (hydrogenotrophic) to be the methanogenic genera present in greatest diversity during stable reactor operation. Methanosaeta sequences predominated at the lowest BWG loading while those of Methanomicrobium were present in greatest abundance at the higher BWG loadings. Genus Candidatus cloacamonas was present in the greatest number of bacterial sequences at all loadings. Alkalinity, pH, biogas production and methane yield declined and VFA concentrations (especially propionate) increased during the highest BWG loading.

  20. Polycyclic Aromatic Hydrocarbon Affects Acetic Acid Production during Anaerobic Fermentation of Waste Activated Sludge by Altering Activity and Viability of Acetogen.

    Science.gov (United States)

    Luo, Jingyang; Chen, Yinguang; Feng, Leiyu

    2016-07-05

    Till now, almost all the studies on anaerobic fermentation of waste activated sludge (WAS) for bioproducts generation focused on the influences of operating conditions, pretreatment methods and sludge characteristics, and few considered those of widespread persistent organic pollutants (POPs) in sludge, for example, polycyclic aromatic hydrocarbons (PAHs). Herein, phenanthrene, which was a typical PAH and widespread in WAS, was selected as a model compound to investigate its effect on WAS anaerobic fermentation for short-chain fatty acids (SCFAs) accumulation. Experimental results showed that the concentration of SCFAs derived from WAS was increased in the presence of phenanthrene during anaerobic fermentation. The yield of acetic acid which was the predominant SCFA in the fermentation reactor with the concentration of 100 mg/kg dry sludge was 1.8 fold of that in the control. Mechanism exploration revealed that the present phenanthrene mainly affected the acidification process of anaerobic fermentation and caused the shift of the microbial community to benefit the accumulation of acetic acid. Further investigation showed that both the activities of key enzymes (phosphotransacetylase and acetate kinase) involved in acetic acid production and the quantities of their corresponding encoding genes were enhanced in the presence of phenanthrene. Viability tests by determining the adenosine 5'-triphosphate content and membrane potential confirmed that the acetogens were more viable in anaerobic fermentation systems with phenanthrene, which resulted in the increased production of acetic acid.

  1. Data summary of municipal solid waste management alternatives. Volume 10, Appendix H: Anaerobic digestion of MSW

    Energy Technology Data Exchange (ETDEWEB)

    None

    1992-10-01

    While municipal solid waste (MSW) thermoconversion and recycling technologies have been described in Appendices A through E, this appendix addresses the role of bioconversion technologies in handling the organic fraction in MSW and sewage sludge. Much of the organic matter in MSW, consisting mainly of paper, food waste, and yard waste, has potential for conversion, along with sewage sludge, through biochemical processes to methane and carbon dioxide providing a measurable, renewable energy resource potential. The gas produced may be treated for removal of carbon dioxide and water, leaving pipeline quality gas. The process also has the potential for producing a stabilized solid product that may be suitable as a fuel for combustion or used as a compost fertilizer. Anaerobic digestion can occur naturally in an uncontrolled environment such as a landfill, or it can occur in a controlled environment such as a confined vessel. Landfill gas production is discussed in Appendix F. This appendix provides information on the anaerobic digestion process as it has been applied to produce methane from the organic fraction of MSW in enclosed, controlled reactors.

  2. Liquid digestate from anaerobic treatment of source-separated household waste as fertilizer to barley.

    Science.gov (United States)

    Haraldsen, Trond Knapp; Andersen, Uno; Krogstad, Tore; Sørheim, Roald

    2011-12-01

    This study examined the efficiency of different organic waste materials as NPK fertilizer, in addition to the risk for leaching losses related to shower precipitation in the first part of the growing season. The experiment was tested in a pot trial on a sandy soil in a greenhouse. Six organic fertilizers were evaluated: liquid anaerobic digestate (LAD) sourced from separated household waste, nitrified liquid anaerobic digestate (NLAD) of the same origin as LAD, meat and bone meal (MBM), hydrolysed salmon protein (HSP), reactor-composted catering waste (CW) and cattle manure (CM). An unfertilized control, calcium nitrate (CN) and Fullgjødsel® 21-4-10 were used as reference fertilizers. At equal amounts of mineral nitrogen both LAD and Fullgjødsel® gave equal yield of barley in addition to equal uptake of N, P, and K in barley grain. NLAD gave significantly lower barley yield than the original LAD due to leaching of nitrate-N after a simulated surplus of precipitation (28 mm) at Zadoks 14. There was significantly increased leaching of nitrate N from the treatments receiving 160 kg N ha(-1) of CN and NLAD in comparison with all the other organic fertilizers. In this study LAD performed to the same degree as Fullgjødsel® NPK fertilizer and it was concluded that LAD can be recommended as fertilizer for cereals. Nitrification of the ammonium N in the digestate caused significantly increased nitrate leaching, and cannot be recommended.

  3. A simple method to evaluate the short-term biogas yield in anaerobic codigestion of WAS and organic wastes.

    Science.gov (United States)

    Scaglione, D; Caffaz, S; Ficara, E; Malpei, F; Lubello, C

    2008-01-01

    The present study was aimed at setting and applying a procedure to measure the anaerobic degradability of different organic substrates by short-term tests (2-7 days) carried out at lab-scale with a low food to biomass (F/M) ratio. All tests were carried out using an acclimated sludge taken from a pilot-plant anaerobic digester (200 L). Trials were performed with a manometric system. The experimental reliability of the device in measuring the anaerobic degradability was assessed by several preliminary tests carried out using acetate and glucose as reference substrates. The average conversion to methane was 99% for acetate and of 83% for glucose. The results of tests in triplicate showed the high repeatability of the method with an average coefficient of variation lower than 2%. Then, the lab-scale procedure was applied to study the short-term anaerobic degradability of complex organic substrates: thickened waste activated sludge, two kinds of organic fraction of municipal solid waste (a kitchen waste and a fruit and vegetable waste collected at the wholesale market of Florence), olive mill wastewater and freshly harvested grass. Results indicated that organic fraction of municipal solid waste, olive mill wastewater and grass were characterized by a much higher anaerobic degradability if compared to the thickened activated sludge, well in agreement with literature data.

  4. Effective distribution of emulsified edible oil for enhanced anaerobic bioremediation

    Science.gov (United States)

    Borden, Robert C.

    2007-10-01

    Recent laboratory and field studies have shown that injection of emulsified edible oils can provide an effective, low-cost alternative for stimulating anaerobic biodegradation processes. A pilot-scale permeable reactive bio-barrier (PRBB) was installed at a perchlorate and chlorinated solvent impacted site by injecting 380 L of commercially available emulsion (EOS ®) containing emulsified soybean oil, food-grade surfactants, lactate, and yeast extract through ten direct push injection wells over a two day period. Soil cores collected six months after emulsion injection indicate the oil was distributed up to 5 m downgradient of the injection wells. A previously developed emulsion transport model was used to simulate emulsion transport and retention using independently estimated model parameters. While there was considerable variability in the soil sampling results, the model simulations generally agreed with the observed oil distribution at the field site. Model sensitivity analyses indicate that increasing the injection flow rate or diluting the oil with more water will have little effect on final oil distribution in the aquifer. The only effective approach for enhancing the spread of emulsified oil away from the injection well appears to be injecting a greater mass of oil.

  5. Anaerobic digestion and co-digestion of slaughterhouse waste (SHW): influence of heat and pressure pre-treatment in biogas yield.

    Science.gov (United States)

    Cuetos, M J; Gómez, X; Otero, M; Morán, A

    2010-10-01

    Mesophilic anaerobic digestion (34+/-1 degrees C) of pre-treated (for 20 min at 133 degrees C, >3 bar) slaughterhouse waste and its co-digestion with the organic fraction of municipal solid waste (OFMSW) have been assessed. Semi-continuously-fed digesters worked with a hydraulic retention time (HRT) of 36 d and organic loading rates (OLR) of 1.2 and 2.6 kg VS(feed)/m(3)d for digestion and co-digestion, respectively, with a previous acclimatization period in all cases. It was not possible to carry out an efficient treatment of hygienized waste, even less so when OFMSW was added as co-substrate. These digesters presented volatile fatty acids (VFA), long chain fatty acids (LCFA) and fats accumulation, leading to instability and inhibition of the degradation process. The aim of applying a heat and pressure pre-treatment to promote splitting of complex lipids and nitrogen-rich waste into simpler and more biodegradable constituents and to enhance biogas production was not successful. These results indicate that the temperature and the high pressure of the pre-treatment applied favoured the formation of compounds that are refractory to anaerobic digestion. The pre-treated slaughterhouse wastes and the final products of these systems were analyzed by FTIR and TGA. These tools verified the existence of complex nitrogen-containing polymers in the final effluents, confirming the formation of refractory compounds during pre-treatment.

  6. Effects of disinfectants and antibiotics on the anaerobic digestion of piggery waste

    Energy Technology Data Exchange (ETDEWEB)

    Poels, J.; Van Assche, P.; Verstraete, W.

    1984-01-01

    The effects of disinfectants and antibiotics on the anaerobic digestion of piggery waste were investigated. The disinfectants Tego 51, Dettol, NaOCl and Creolin, and the antibiotics, chlortetracyclin, tylosin, erythromycin, chloramphenicol, bacitracin and virginiamycin were tested at different concentrations. At concentrations normally used in practice, no inhibitory effect on methanisation process was detected. However, higher concentrations of the antimicrobial agents, Dettol, Creolin, bacitracin and virginiamycin, markedly inhibited biogas production. In order to minimize possible digester failures, farmers are advised to respect the normal recommended dose and to use low-toxicity antimicrobial agents. (Refs. 8).

  7. Bio-Gas production from municipal sludge waste using anaerobic membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Lee, S.

    2009-07-01

    A laboratory scale anaerobic membrane bioreactor (AnMBR) system for the bio-methane gas production was operated for 60 days with municipal sludge wastes as a sole carbon source. The AnMRR system utilized the external cross-flow membrane module and was equipped with on-line data acquisition which enables continuous monitoring of the performance of both bioreactor and membrane through the analyses of pH, temperature, gas production; permeate flow rate, and transmembrane pressure (TMP). Such a configuration also provides an efficient tool to study rapid variations of monitoring membrane pressure (TMP). (Author)

  8. Anaerobic digestion of the shredded organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Traverso, P.G.; Cecchi, Franco

    1988-01-01

    Anaerobic digestion of the shredded organic fraction of municipal solid waste has been investigated in a pilot-scale completely mixed digester, under mesophilic conditions. Detailed comparisons of the size distributions of the particles in the feed and in the digester effluent are reported under varying organic loading rates and hydraulic retention times. About 20% of the particulate matter in the organic feed is refractory and resists hydrolysis. Hence the maximum removal of total volatile solids attainable under hydraulic retention times of practical interest is about 70%. The optimum hydraulic retention time is around 14 to 15 days.

  9. Hydrogen Production By Anaerobic Fermentation Using Agricultural and Food Processing Wastes Utilizing a Two-Stage Digestion System

    OpenAIRE

    Thompson, Reese S

    2008-01-01

    Hydrogen production by means of anaerobic fermentation was researched utilizing three different substrates. Synthetic wastewater, dairy manure, and cheese whey were combined together at different concentrations under batch anaerobic conditions to determine the optimal hydrogen producing potential and waste treatment of each. Cheese whey at a concentration of 55% was combined with dairy manure at a concentration of 45% to produce 1.53 liters of hydrogen per liter of substrate. These results...

  10. A Novel Process Configuration for Anaerobic Digestion of Source-Sorted Household Waste Using Hyper-Thermophilic Post-Treatment

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2005-01-01

    A novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper-thermophilic (68°C) reactor R68 was implemented as a post–treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance...... hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction and volatile fatty acid (VFA) production at different hydraulic retention times (HRT......). A single-stage thermophilic (55°C) reactor R2 was used as control. VS reduction and biogas yield of the combined system was 78 – 89% and 640 – 790 ml/g-VS, respectively. While the VS reduction in the combined system was up to 7% higher than in the single-stage treatment, no increase in methane yield...

  11. Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.

    Science.gov (United States)

    García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel

    2015-01-01

    A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.

  12. Effects of feedstock carbon to nitrogen ratio and organic loading on foaming potential in mesophilic food waste anaerobic digestion.

    Science.gov (United States)

    Tanimu, Musa Idris; Mohd Ghazi, Tinia Idaty; Harun, Mohd Razif; Idris, Azni

    2015-05-01

    Foaming problem which occurred occasionally during food waste (FW) anaerobic digestion (AD) was investigated with the Malaysian FW by stepwise increase in organic loading (OL) from 0.5 to 7.5 g VS/L. The FW feedstock with carbon to nitrogen (C/N) ratio of 17 was upgraded to C/N ratio of 26 and 30 by mixing with other wastes. The digestion which was carried out at 37 °C in 1-L batch reactors showed that foam formation initiated at OL of 1.5 g VS/L and was further enhanced as OL of feedstock was increased. The digestion foaming reached its maximum at OL of 5.5 g VS/L and did not increase further even when OL was increased to 7.5 g VS/Ld. Increase in the C/N ratio of feedstock significantly enhanced the microbial degradation activity, leading to better removal of foam causing intermediates and reduced foaming in the reactor by up to 60%.

  13. Effect of increasing total solids contents on anaerobic digestion of food waste under mesophilic conditions: performance and microbial characteristics analysis.

    Directory of Open Access Journals (Sweden)

    Jing Yi

    Full Text Available The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.

  14. Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis

    Science.gov (United States)

    Jin, Jingwei; Dai, Xiaohu

    2014-01-01

    The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies. PMID:25051352

  15. Fungal pretreatment of albizia chips for enhanced biogas production by solid-state anaerobic digestion

    Science.gov (United States)

    Albizia biomass is a forestry waste, and holds a great potential in biogas production by solid-state anaerobic digestion (SS-AD). However, low methane yields from albizia chips were observed due to their recalcitrant structure. In this study, albizia chips were pretreated by Ceriporiopsis subvermisp...

  16. Numerical study on anaerobic digestion of fruit and vegetable waste: Biogas generation

    Science.gov (United States)

    Wardhani, Puteri Kusuma; Watanabe, Masaji

    2016-02-01

    The study provides experimental results and numerical results concerning anaerobic digestion of fruit and vegetable waste. Experiments were carried out by using batch floating drum type digester without mixing and temperature setting. The retention time was 30 days. Numerical results based on Monod type model with influence of temperature is introduced. Initial value problems were analyzed numerically, while kinetic parameters were analyzed by using trial error methods. The numerical results for the first five days seems appropriate in comparison with the experimental outcomes. However, numerical results shows that the model is inappropriate for 30 days of fermentation. This leads to the conclusion that Monod type model is not suitable for describe the mixture degradation of fruit and vegetable waste and horse dung.

  17. Mobilization of radionuclides from uranium mill tailings and related waste materials in anaerobic environments

    Science.gov (United States)

    Landa, E.R.

    2003-01-01

    Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions.

  18. Influence of temperature on performance of anaerobic digestion of municipal solid waste

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ji-shi; SUN Ke-wei; WU Man-chang; ZHANG Lei

    2006-01-01

    The influence of temperature on the performance of anaerobic reactors for treating the organic fraction of municipal solid waste (OFMSW) was studied. Batch digestion of OFMSW was carried out for 32 d at different temperature (25℃, 35℃, 45℃ and 55℃) conditions for total solid concentrations (TS) 17% with the ratio of total organic carbon to nitrogen (C/N) being, 25:1 respectively, while keeping other parameters constant such as inoculum, start-up pH, reactor volume (2 L) and so on. Temperature can influence the methanogenic bacteria activity, accordingly inhibiting the OFMSW biodegradation and stabilization efficiency.Anaerobic reactors excelled at TS reduction, total volatile solid reduction, chemical oxygen demand reduction, increasing cumulative biogas production, whose rate was at temperature (35℃ and 55℃) conditions. Methane concentration in the biogas was above 65% in four reactors. In addition, the fluctuation of temperatures resulted in the biogas production variation. The data obtained indicated that temperature had a significant influence on anaerobic process.

  19. Hyperspectral imaging techniques applied to the monitoring of wine waste anaerobic digestion process

    Science.gov (United States)

    Serranti, Silvia; Fabbri, Andrea; Bonifazi, Giuseppe

    2012-11-01

    An anaerobic digestion process, finalized to biogas production, is characterized by different steps involving the variation of some chemical and physical parameters related to the presence of specific biomasses as: pH, chemical oxygen demand (COD), volatile solids, nitrate (NO3-) and phosphate (PO3-). A correct process characterization requires a periodical sampling of the organic mixture in the reactor and a further analysis of the samples by traditional chemical-physical methods. Such an approach is discontinuous, time-consuming and expensive. A new analytical approach based on hyperspectral imaging in the NIR field (1000 to 1700 nm) is investigated and critically evaluated, with reference to the monitoring of wine waste anaerobic digestion process. The application of the proposed technique was addressed to identify and demonstrate the correlation existing, in terms of quality and reliability of the results, between "classical" chemical-physical parameters and spectral features of the digestate samples. Good results were obtained, ranging from a R2=0.68 and a RMSECV=12.83 mg/l for nitrate to a R2=0.90 and a RMSECV=5495.16 mg O2/l for COD. The proposed approach seems very useful in setting up innovative control strategies allowing for full, continuous control of the anaerobic digestion process.

  20. Enhanced biogas production by anaerobic co-digestion from a trinary mix substrate over a binary mix substrate.

    Science.gov (United States)

    Ara, Efath; Sartaj, Majid; Kennedy, Kevin

    2015-06-01

    The synergetic enhancement of mesophilic anaerobic co-digestion of trinary and binary mix of organic fraction of municipal solid waste (OFMSW) + primary sludge (PS) + thickened waste activated sludge (TWAS) as substrates was investigated through batch biological methane potential (BMP) and semi-continuous flow reactor tests. Cumulative biogas yield (CBY) yield for the binary mix of OFMSW:TWAS was 555, 580, and 660 mL/g volatile solids (VS)added for an OFMSW:TWAS ratio of 25:75, 50:50, and 75:25, respectively, which was 48, 78.5, and 140% higher than the calculated expected biogas (CEB) yield from the corresponding individual substrates. The trinary mixture of OFMSW:TWAS:PS at ratios of 25:37.5:375.5, 50:25:25 and 75:12.5:12.5 was able to produce 680, 710 and 780 mL/g VSadded, respectively, which was 25.5, 62.0 and 135.6% more biogas than the calculated expected biogas yield from the corresponding individual substrates. Cumulative methane yield (CMY) of trinary mixtures was also higher than the corresponding binary mixtures (20, 27, and 12 % increase for OFMSW:TWAS:PS at a ratio of 25:37.5:37.5, 50:25:25, and 75:12.5:12.5 compared to the binary mix of OFMSW:TWAS at a ratio of 25:75, 50:50, and 75:25, respectively). Methane content of the biogas varied from 54 to 57%. The results from semi-continuous flow anaerobic reactors under hydraulic retention times (HRT) of 15, 10 and 7 days supported the results of batch biological methane potential tests. The results were conclusive that enhancement in biogas production was noticeably higher from the co-digestion of trinary mix of organic fraction of municipal solid waste+ thickened waste activated sludge + primary sludge than the binary mix organic fraction of municipal solid waste+thickened waste activated sludge or thickened waste activated sludge+primary sludge with concomitant improvements in VS removal and biodegradability for tri-digestion of organic fraction of municipal solid waste, thickened waste activated sludge

  1. Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants.

    Science.gov (United States)

    Gruden, Cyndee L; Hernandez, Mark

    2002-01-01

    Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.

  2. Evaluation and characterization during the anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor.

    Science.gov (United States)

    Xiao, Xiaolan; Huang, Zhenxing; Ruan, Wenquan; Yan, Lintao; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing

    2015-10-01

    The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs.

  3. Separation of inerts by differential sedimentation as previous stage to anaerobic digestion of organic fraction from municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, C.; Martinez, V.; Esplugas, P.

    2009-07-01

    Municipal solid waste (MSW) treatment plants have as main function the valuation of municipal waste by means of materials recovery and valuation of organic fraction. In this type of facilities, the anaerobic digestion is a biological treatment of the organic matter collected in origin or mechanically separated from the mixed MSM. The objective is its valuation under the form of biogas and organic compost. Anaerobic digestion has high energy efficiency and a good range or organic matter elimination. Nevertheless, treatment of organic matter recovered from mixed MSW presents serious operation problems due to sedimentation of heavy improper materials (sands, glasses, metals) and flotation of light materials inside the digestors and piping. (Author)

  4. State of the art of R and D in the anaerobic digestion process of municipal solid waste in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F.; Traverso, P.G.; Mata-Alvarez, J.; Clancy, J.; Zaror, C.

    1988-01-01

    The state of the art of R and D in the field of anaerobic digestion of municipal solid waste in Europe is reviewed. A comparison is made of the quality and quantity of refuse produced in different European countries using data available in recent literature. The conclusion to be drawn from this analysis is that in programmes involving demonstration and full scale plants it is necessary to carry out more detailed studies of the process and its control, as well as carrying out further work on the microbiological aspects of anaerobic digestion of municipal solid waste.

  5. Biogas Production from Batch Anaerobic Co-Digestion of Night Soil with Food Waste

    Directory of Open Access Journals (Sweden)

    Assadawut Khanto

    2016-01-01

    Full Text Available The objective of this study is to investigate the biogas production from Anaerobic Co-Digestion of Night Soil (NS with Food Waste (FW. The batch experiment was conducted through the NS and FW with a ratio of 70:30 by weight. The experiment is mainly evaluated by the characteristic of Co-Digestion and Biogas Production. In addition of food waste was inflating the COD loading from 17,863 to 42,063 mg/L which is 135 % increased. As the result, it shows that pH has dropped off in the beginning of 7-day during digestion and it was slightly increased into the range of optimum anaerobic condition. After digestion of the biogas production was 2,184 l and 56.5 % of methane fraction has obtained within 31 days of experimentation. The investigation of Biochemical Methane Potential (BMP and Specific Methanogenic Activities (SMA were highly observed. And the results were obtained by 34.55 mL CH4/gCODremoval and 0.38 g CH4-COD/gVSS-d. While the average COD removal from the 4 outlets got 92%, 94%, 94 % and 92 % respectively. However, the effluent in COD concentration was still high and it needs further treatment before discharge.

  6. Modeling and simulation of lab-scale anaerobic co-digestion of MEA waste

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2014-01-01

    Full Text Available Anaerobic digestion model No.1 (ADM1 was applied and expanded in this study to model and simulate anaerobic digestion (AD of an industrial carbon capture reclaimer MEA (monoethanolamine waste (MEAw together with easily degradable organics. The general structure of ADM1 was not changed except for introducing state variables of MEA and complex organics (CO in the waste and biochemical reactions of MEA uptake and CO hydrolysis in the model ADM1_MEAw. Experimental batch test results were used for calibrating kinetics variables. The obtained kinetics were employed in the ADM1_MEAw to simulate semi-continuously fed experimental test for 486 days at room temperature (22 +/- 2oC. The validation results show that the ADM1_MEAw was able to predict the process performance with reasonable accuracy, including process pH, biogas generation and inorganic nitrogen concentrations, for a wide range of feed scenarios. Free ammonia inhibition, was observed to be the main inhibitory effects on acetoclastic methanogenesis, leading to volatile fatty acids (VFA accumulation at high loads. Inhibition assumed to be caused by potentially toxic constituents of MEAw appears to be much less important than ammonia, suggesting that such constituents were broken down by AD.

  7. The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation

    Science.gov (United States)

    Hariyadi, H. R.

    2017-03-01

    The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation was carried out as well as the influence phenol and benzoate, and biodegradation of bromuconazole. Bromuconazole is a fungicide effective against Ascomycetes, Basidiomycetes and fungi imperfecti in cereals, grapes, top fruits and vegetables. It is also effective against Alternaria and Fusarium sp. The remaining fungicide in leaves might contaminates landfill. One month of organic waste added with bromuconazole was anaerobically incubated in 500 mL bottles at 30°C without shaking in dark room. High-Performance Liquid Chromatography (HPLC) with UV detector and a 100 RP 185μm Lichrosphere column was used to determine bromuconazole concentration. Methane content was determined by Gas Chromatography (GC) method equipped with a flame ionization detector and a metal column packed with 5% neopentyl glycol sebacate and 1% H3PO4 on Chromosorb W-AW (mesh 80-100). After incubation for 225 days, bromuconazole of 200 mg/L inhibited the production of methane (99.5 mM) significantly, but did not inhibit the production of volatile fatty acids. The addition of 100 mg/L phenol or 146 mg/L benzoate increased the production of methane, 143 mM and 135.2 mM, respectively compared with control (121.8 mM). In anaerobic conditions, the presence of toxic pollutants such as fungicide bromuconazole in landfills sites may cause further problems with the accumulation of volatile fatty acids in leachate. Further study to determine the threshold, the presence of bromconazole in low concentration (less than 200 mg/L) on the methane production is recommended.

  8. Influence of feeding mixture composition in batch anaerobic co-digestion of stabilized municipal sludge and waste from dairy farms.

    Science.gov (United States)

    Trulli, Ettore; Torretta, Vincenzo

    2015-01-01

    Waste anaerobic co-digestion applications are particularly useful in Southern Mediterranean areas where large quantities of agricultural waste materials and waste from agro-industries are produced. This waste can be added to urban waste together with the sludge produced by wastewater treatment processes, which, when combined, guarantee the supply of organic matrixes for treatment throughout the year. The implementation of facilities to service vast areas of the agricultural economy and which are heterogeneous in terms of production can provide a good solution. We present an experimental investigation into the anaerobic co-digestion of municipal sludge and bio-waste produced in the Mediterranean area. We conducted anaerobic treatability tests, with measures of biogas production and pH of the mixture in digestion. Our main aims were to identify an optimal mix of substrates for the production of biogas, and to analyse the influence on the composition of biogas and the variation in pH values of the substrates. This analysis was conducted considering the variation of the input, in particular due to the addition of waste acids, such as biological sewage sludge.

  9. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Suyun [Department of Environmental and Low-Carbon Science, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai (China); Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Selvam, Ammaiyappan [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Wong, Jonathan W.C., E-mail: jwcwong@hkbu.edu.hk [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong)

    2014-02-15

    Highlights: • Effect of micro-aeration on acidogenesis and hydrolysis of food waste was investigated. • Micro-aeration at 258 L-air/kg TS/d increased the VFAs production 3-fold. • High aeration leads to loss of substrate through microbial biomass and respiration. • Optimum aeration increased methane recovery while high aeration intensity reduced methane yield. - Abstract: Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35 °C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21–27% and 38–64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH{sub 4}/g VS{sub added} in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO{sub 2} respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  10. Influences of green wastes on anaerobic digestion of sludge and kitchen wastes%不同园林废弃物对污泥和餐厨垃圾厌氧消化的影响

    Institute of Scientific and Technical Information of China (English)

    邵敬; 罗文邃; 万顺刚; 孙健; 唐晓达

    2013-01-01

    Series of experiments were conducted to investigate the influences of 3 green wastes (sugarcane leaves,Ipo-moea obscura L. ,and Acacia pennata L. ) on anaerobic digestion of sludge and kitchen wastes in lab-scale reactors. The results showed that the addition of green wastes enhanced sludge anaerobic digestion in biogas production and methane yields. Mixing the sludge and sugarcane leaves in the wet weight ratio of 5 : 3,the obtained mixture exhibited the best anaerobic digestion efficiency,the total biogas and methane production were 22. 4 and 37. 7 times of that in single sludge anaerobic digestion group. However, sugarcane leaves showed limited effect on the improvement of kitchen waste anaerobic digestion. In contrast,the addition of Acacia pennata L. inhibited the anaerobic digestion of kitchen wastes; the total biogas production was decreased by 48% after adding equal quantity of Acacia pennata L..%将甘蔗叶、小心叶薯和合欢按不同的物料配比加入到污泥和餐厨垃圾中,考察了3种园林废弃物对污泥和餐厨垃圾厌氧消化处理的影响.实验结果表明,添加小心叶薯、甘蔗叶和合欢可显著提高污泥厌氧消化的沼气总产量以及甲烷总产量.当污泥与甘蔗叶以5:3的湿质量比混合时厌氧消化效果最佳,此时沼气总产量、甲烷总产量分别为污泥对照组的22.4、37.7倍.然而,甘蔗叶对提高餐厨垃圾厌氧消化效果的作用有限,合欢对餐厨垃圾厌氧消化具有明显抑制作用,添加合欢后沼气总产量比餐厨对照组低48%.

  11. Evaluation of a new pulping technology for pre-treating source-separated organic household waste prior to anaerobic digestion

    DEFF Research Database (Denmark)

    Naroznova, Irina; Møller, Jacob; Larsen, Bjarne

    2016-01-01

    A new technology for pre-treating source-separated organic household waste prior to anaerobic digestion was assessed, and its performance was compared to existing alternative pre-treatment technologies. This pre-treatment technology is based on waste pulping with water, using a specially developed...... screw mechanism. The pre-treatment technology rejects more than 95% (wet weight) of non-biodegradable impurities in waste collected from households and generates biopulp ready for anaerobic digestion. Overall, 84-99% of biodegradable material (on a dry weight basis) in the waste was recovered...... in the biopulp. The biochemical methane potential for the biopulp was 469±7mL CH4/g ash-free mass. Moreover, all Danish and European Union requirements regarding the content of hazardous substances in biomass intended for land application were fulfilled. Compared to other pre-treatment alternatives, the screw...

  12. Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production.

    Science.gov (United States)

    Yazdani, Ramin; Barlaz, Morton A; Augenstein, Don; Kayhanian, Masoud; Tchobanoglous, George

    2012-05-01

    The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3MWh, or 46kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.

  13. Thermal hydrolysis integration in the anaerobic digestion process of different solid wastes: energy and economic feasibility study.

    Science.gov (United States)

    Cano, R; Nielfa, A; Fdz-Polanco, M

    2014-09-01

    An economic assessment of thermal hydrolysis as a pretreatment to anaerobic digestion has been achieved to evaluate its implementation in full-scale plants. Six different solid wastes have been studied, among them municipal solid waste (MSW). Thermal hydrolysis has been tested with batch lab-scale tests, from which an energy and economic assessment of three scenarios is performed: with and without energy integration (recovering heat to produce steam in a cogeneration plant), finally including the digestate management costs. Thermal hydrolysis has lead to an increase of the methane productions (up to 50%) and kinetics parameters (even double). The study has determined that a proper energy integration design could lead to important economic savings (5 €/t) and thermal hydrolysis can enhance up to 40% the incomes of the digestion plant, even doubling them when digestate management costs are considered. In a full-scale MSW treatment plant (30,000 t/year), thermal hydrolysis would provide almost 0.5 M€/year net benefits.

  14. Evaluating and modeling biogas production from municipal fat, oil, and grease and synthetic kitchen waste in anaerobic co-digestions.

    Science.gov (United States)

    Li, Chenxi; Champagne, Pascale; Anderson, Bruce C

    2011-10-01

    The feasibility of using synthetic kitchen waste (KW) and fat, oil, and grease (FOG) as co-substrates in the anaerobic digestion of waste activated sludge (WAS) was investigated using two series of biochemical methane potential (BMP) tests. Ranges of ideal substrate to inoculum (S/I) ratio were determined for the FOG (0.25-0.75) and KW (0.80-1.26) as single substrates in the first experiment. The second experiment, which estimated the methane production performances of FOG and KW as co-substrates for WAS co-digestion, was conducted based on the optimal parameters selected from the results of the first experiment. Results indicated that co-digestions with FOG and KW enhanced methane production from 117±2.02 mL/gTVS (with only WAS) to 418±13.7 mL/gTVS and 324±4.11 mL/gTVS, respectively. FOG exhibited more biogas production than KW as co-substrate. Non-linear regression results showed that co-substrate addition shortened the lag phases of organic biodegradation from 81.8 (with only WAS) to 28.3 h with FOG and 3.90 h with KW.

  15. Effects of mixture ratio on anaerobic co-digestion with fruit and vegetable waste and food waste of China

    Institute of Scientific and Technical Information of China (English)

    Jia Lin; Jiane Zuo; Lili Gan; Peng Li; Fenglin Liu; Kaijun Wang; Lei Chen; Hainan Gan

    2011-01-01

    The biochemical methane potentials for typical fruit and vegetable waste (FVW) and food waste (FW) from a northern China city were investigated,which were 0.30,0.56 m3 CH4/kgVS (volatile solids) with biodegradabilities of 59.3% and 83.6%,respectively.Individual anaerobic digestion testes of FVW and FW were conducted at the organic loading rate (OLR) of 3 kg VS/(m3·day) using a lab-scale continuous stirred-tank reactor at 35℃.FVW could be digested stably with the biogas production rate of 2.17 m3/(m3.day) and methane production yield of 0.42 m3 CHl4/kg VS.However,anaerobic digestion process for FW was failed due to acids accumulation.The effects of FVW:FW ratio on co-digestion stability and performance were further investigated at the same OLR.At FVW and FW mixing ratios of 2:1 and 1:1,the performance and operation of the digester were maintained stable,with no accumulation of volatile fatty acids (VFA) and ammonia.Changing the feed to a higher FW content in a ratio of FVW to FW 1:2,resulted in an increase in VFAs concentration to 1100-1200 mg/L,and the methanogenesis was slightly inhibited.At the optimum mixture ratio 1:1 for co-digestion of FVW with FW,the methane production yield was 0.49 m3 CHl4/kg VS,and the volatile solids and soluble chemical oxygen demand (sCOD) removal efficiencies were 74.9% and 96.1%,respectively.

  16. Principles and potential of the anaerobic digestion of waste-activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Appels, Lise; Degreve, Jan [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Baeyens, Jan [Department of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Dewil, Raf [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Department of Chemical Engineering, Associated Faculty of Technology and Biosciences, Campus De Nayer, Katholieke Universiteit Leuven, Jan De Nayerlaan 5, B-2860 Sint-Katelijne-Waver (Belgium)

    2008-12-15

    When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60-70 vol% of methane, CH{sub 4}), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include

  17. Consecutive anaerobic-aerobic treatment of the organic fraction of municipal solid waste and lignocellulosic materials in laboratory-scale landfill-bioreactors.

    Science.gov (United States)

    Pellera, Frantseska-Maria; Pasparakis, Emmanouil; Gidarakos, Evangelos

    2016-10-01

    The scope of this study is to evaluate the use of laboratory-scale landfill-bioreactors, operated consecutively under anaerobic and aerobic conditions, for the combined treatment of the organic fraction of municipal solid waste (OFMSW) with two different co-substrates of lignocellulosic nature, namely green waste (GW) and dried olive pomace (DOP). According to the results such a system would represent a promising option for eventual larger scale applications. Similar variation patterns among bioreactors indicate a relatively defined sequence of processes. Initially operating the systems under anaerobic conditions would allow energetic exploitation of the substrates, while the implementation of a leachate treatment system ultimately aiming at nutrient recovery, especially during the anaerobic phase, could be a profitable option for the whole system, due to the high organic load that characterizes this effluent. In order to improve the overall effectiveness of such a system, measures towards enhancing methane contents of produced biogas, such as substrate pretreatment, should be investigated. Moreover, the subsequent aerobic phase should have the goal of stabilizing the residual materials and finally obtain an end material eventually suitable for other purposes.

  18. Anaerobic treatment as a core technology for energy, nutrients and water from source-separated domestic waste(water)

    NARCIS (Netherlands)

    Zeeman, G.; Kujawa, K.; Mes, de T.Z.D.; Graaff, de M.S.; Abu-Ghunmi, L.N.A.H.; Mels, A.R.; Meulman, B.; Temmink, B.G.; Buisman, C.J.N.; Lier, van J.B.; Lettinga, G.

    2008-01-01

    Based on results of pilot scale research with source-separated black water (BW) and grey water (GW), a new sanitation concept is proposed. BW and GW are both treated in a UASB (-septic tank) for recovery of CH4 gas. Kitchen waste is added to the anaerobic BW treatment for doubling the biogas product

  19. Anaerobic digestion of waste activated sludge—comparison of thermal pretreatments with thermal inter-stage treatments

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Thygesen, Anders; Thomsen, Anne Belinda

    2011-01-01

    BACKGROUND: Treatment methods for improved anaerobic digestion (AD) of waste activated sludge were evaluated. Pretreatments at moderate thermal (water bath at 80 °C), high thermal (loop autoclave at 130–170 °C) and thermo-chemical (170 °C/pH 10) conditions prior to AD in batch vials (40 days/37 °C...

  20. Operational strategies for thermophilic anaerobic digestion of organic fraction of municipal solid waste in continuously stirred tank reactors

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Cui, J.; Chen, X.;

    2006-01-01

    Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor proces...

  1. Full-scale anaerobic co-digestion of organic waste and municipal sludge

    Energy Technology Data Exchange (ETDEWEB)

    Zupancic, Gregor D.; Ros, Milenko [National Institute of Chemistry, Hajdrihova 19, PO Box 660, SI-1001 Ljubljana (Slovenia); Uranjek-Zevart, Natasa [Municipality of Velenje, Koroska 37/b, 3320 Velenje (Slovenia)

    2008-02-15

    A full-scale experiment on the anaerobic co-digestion of organic waste from domestic refuse (swill) and municipal sludge is described. In a wastewater treatment plant of 50,000 population equivalents, two conventional mesophilic digesters with a combined volume of 2000 m{sup 3} and 20 days hydraulic retention time were used. The digesters' usual influent is waste sludge from wastewater treatment plants (a mixture of primary sludge and waste activated sludge) with an average organic loading rate of 0.8 kg m{sup -3} d{sup -1} of volatile suspended solids. In the experiment, organic waste was added to the digester influent to increase the organic loading rate by 25% to 1.0 kg m{sup 3} d{sup -1} of volatile suspended solids. Biogas quantity increased by 80% and specific biogas production increased from 0.39 m{sup 3} kg{sup -1} volatile suspended solids inserted prior to the experiment to over 0.60 m{sup 3} kg{sup -1} volatile suspended solids' inserted, peaking at 0.89 m{sup 3} kg{sup -1} volatile suspended solids inserted. The excess biogas was used in a boiler and a 50 kW combined heat and power engine. Electrical energy production increased by 130% and heat production increased by 55%. Volatile suspended solids degradation efficiency increased from 71% to 81% with no increase of volatile suspended solids in the digester effluent. Virtually all of the organic waste was degraded. (author)

  2. Microbial Anaerobic Digestion (Bio-Digesters) as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    OpenAIRE

    Manyi-Loh, Christy E.; Sampson N. Mamphweli; Meyer, Edson L.; Anthony I. Okoh; Makaka, Golden; Simon, Michael

    2013-01-01

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken d...

  3. Lifecycle Greenhouse Gas Analysis of an Anaerobic Codigestion Facility Processing Dairy Manure and Industrial Food Waste.

    Science.gov (United States)

    Ebner, Jacqueline H; Labatut, Rodrigo A; Rankin, Matthew J; Pronto, Jennifer L; Gooch, Curt A; Williamson, Anahita A; Trabold, Thomas A

    2015-09-15

    Anaerobic codigestion (AcoD) can address food waste disposal and manure management issues while delivering clean, renewable energy. Quantifying greenhouse gas (GHG) emissions due to implementation of AcoD is important to achieve this goal. A lifecycle analysis was performed on the basis of data from an on-farm AcoD in New York, resulting in a 71% reduction in GHG, or net reduction of 37.5 kg CO2e/t influent relative to conventional treatment of manure and food waste. Displacement of grid electricity provided the largest reduction, followed by avoidance of alternative food waste disposal options and reduced impacts associated with storage of digestate vs undigested manure. These reductions offset digester emissions and the net increase in emissions associated with land application in the AcoD case relative to the reference case. Sensitivity analysis showed that using feedstock diverted from high impact disposal pathways, control of digester emissions, and managing digestate storage emissions were opportunities to improve the AcoD GHG benefits. Regional and parametrized emissions factors for the storage emissions and land application phases would reduce uncertainty.

  4. Dry-thermophilic anaerobic digestion of simulated organic fraction of municipal solid waste: process modeling.

    Science.gov (United States)

    Fdez-Güelfo, L A; Álvarez-Gallego, C; Sales Márquez, D; Romero García, L I

    2011-01-01

    Solid retention time (SRT) is a very important operational variable in continuous and semicontinuous waste treatment processes since the organic matter removal efficiency--expressed in terms of percentage of Dissolved Organic Carbon (% DOC) or Volatile Solids (% VS) removed--and the biogas or methane production are closely related with the SRT imposed. Optimum SRT is depending on the waste characteristics and the microorganisms involved in the process and, hence, it should be determined specifically in each case. In this work a series of experiments were carried out to determine the effect of SRT, from 40 to 8 days, on the performance of the dry (30% Total Solids) thermophilic (55°C) anaerobic digestion of organic fraction of Municipal Solid Wastes (OFMSW) operating at semicontinuous regime of feeding. The experimental results show than 15days is the optimum SRT (the best between all proved) for this process. Besides, data of organic matter concentration and methane production versus SRT have been used to obtain the kinetic parameters of the kinetic model of Romero García (1991): the maximum specific growth rate of the microorganisms (μmax=0.580 days(-1)) and the fraction of substrate non-biodegradable (α=0.268).

  5. Optimization of methane production by combining organic waste and cow manure as feedstock in anaerobic digestion

    Science.gov (United States)

    Theresia, Martha; Priadi, Cindy Rianti

    2017-03-01

    The anaerobic digestion (AD) process from organic waste is often unstable due to the high concentration of Volatile Fatty Acids (VFAs). The purpose of this research was to determine/evaluate the production of methane using biochemical methane potential (BMP) test with two substrate combinations, consisted of organic waste and cow manure as buffer. BMP test conducted for 35 days at a temperature of ± 35°C by measuring the volume and concentration of biogas every week and testing the sample characteristics before and after the test. The result of the sample variation showed there was no significantly difference of methane volume in the 5th week except the variation of organic waste/cow manure: 12/1 to 3/1, but the sample with a ratio of 3/1 yielded the highest methane potential of 0,58 ± 0.015 (n = 3) LCH4/gr Volatile Solid. The addition of cow manure stabilized the condition of all variations during BMP test with VFAs/alkalinity <0.3 although Carbon/Nitogen ratio of each variation is <20.

  6. Effect of operational pH on biohydrogen production from food waste using anaerobic batch reactors.

    Science.gov (United States)

    Lee, Chaeyoung; Lee, Sewook; Han, Sun-Kee; Hwang, Sunjin

    2014-01-01

    This study was performed to investigate the influence of operational pH on dark H(2) fermentation of food waste by employing anaerobic batch reactors. The highest maximum H(2) yield was 1.63 mol H(2)/mol hexoseadded at operational pH 5.3, whereas the lowest maximum H(2) yield was 0.88 mol H(2)/mol hexoseadded at operational pH 7.0. With decreasing operational pH values, the n-butyrate concentration tended to increase and the acetate concentration tended to decrease. The highest hydrogen conversion efficiency of 11.3% was obtained at operational pH 5.3, which was higher than that (8.3%) reported by a previous study (Kim et al. (2011) 'Effect of initial pH independent of operational pH on hydrogen fermentation of food waste', Bioresource Technology 102 (18), 8646-8652). The new result indicates that the dark fermentation of food waste was stable and efficient in this study. Fluorescence in situ hybridization (FISH) analysis showed that Clostridium species Cluster I accounted for 84.7 and 13.3% of total bacteria at operational pH 5.3 and pH 7.0, respectively, after 48 h operation.

  7. Anaerobic co-digestion of kitchen waste and fruit/vegetable waste: lab-scale and pilot-scale studies.

    Science.gov (United States)

    Wang, Long; Shen, Fei; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Li, Xiujin

    2014-12-01

    The anaerobic digestion performances of kitchen waste (KW) and fruit/vegetable waste (FVW) were investigated for establishing engineering digestion system. The study was conducted from lab-scale to pilot-scale, including batch, single-phase and two-phase experiments. The lab-scale experimental results showed that the ratio of FVW to KW at 5:8 presented higher methane productivity (0.725 L CH4/g VS), and thereby was recommended. Two-phase digestion appeared to have higher treatment capacity and better buffer ability for high organic loading rate (OLR) (up to 5.0 g(VS) L(-1) d(-1)), compared with the low OLR of 3.5 g(VS) L(-1) d(-1) for single-phase system. For two-phase digestion, the pilot-scale system showed similar performances to those of lab-scale one, except slightly lower maximum OLR of 4.5 g(VS) L(-1) d(-1) was allowed. The pilot-scale system proved to be profitable with a net profit of 10.173$/ton as higher OLR (⩾ 3.0 g(VS) L(-1) d(-1)) was used.

  8. Principles and Practices of Enhanced Anaerobic Bioremediation of Chlorinated Solvents

    Science.gov (United States)

    2004-09-01

    and Horney , 1997), mackinawite (Butler and Hayes, 1999 and 2000), and magnetite (Ferrey et al. 2004). In this case, substrate addition may indirectly...reductive dechlorination (e.g., Ferrey et al., 2004; Sivavec and Horney , 1997). The formation of these reactive minerals is of interest in that it...Strictly Anaerobic Bacterium. Archives of Microbiology, Vol. 63:48-56. Sivavec, T.M. and D.P. Horney . 1997. Reduction of Chlorinated Solvents by Fe

  9. High-solid Anaerobic Co-digestion of Food Waste and Rice Straw for Biogas Production

    Institute of Scientific and Technical Information of China (English)

    Pei Zhan-jiang; Liu Jie; Shi Feng-mei; Wang Su; GaoYa-bing; Zhang Da-lei

    2014-01-01

    Anaerobic co-digestion of food waste (FW) and rice straw (RS) in continuously stirred tank reactor (CSTR) at high organic loading rate (OLR) was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid (VS) concentration of more than 3 gVS•L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand (COD) and volatile fatty acids (VFAs) were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 mL•gV•S-1•d-1 at a mass ratio (FW/RS) of 3: 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than mono-digestions in higher organic loading system.

  10. Rheology of sludge from double phase anaerobic digestion of organic fraction of municipal solid waste.

    Science.gov (United States)

    Battistoni, P; Pavan, P; Mata-Alvarez, J; Prisciandaro, M; Cecchi, F

    2000-01-01

    In this paper experimental results on the anaerobic digestion of sewage sludge and organic fraction of municipal solid waste (OFMSW) by using a double phase process are reported. The long-term experiment has been carried out on a pilot scale plant, performed in different sets of operative conditions, during which granulometric distributions of particles in sludges and rheological properties of sludges were monitored. A significant fluidification of sludge was evidenced in the meso-thermo process, especially taking into account the variation in sludge behaviour from the first to the second phase. In the thermo-thermo process a fluidification higher than that shown in meso-thermo conditions is not observed, this suggesting that better results in terms of sludge conditioning can be obtained in a long time spent in thermophilic anaerobic digestion. Total volatile solids (TVS) and total fixed solids (TFS) become the most important parameters when mathematical modelling is applied to these processes. In the acidogenic phase, hydraulic retention time (HRT) and temperature are used to determine rigidity coefficient (RC), while only temperature is needed for yield stress (YC). Organic loading rate (OLR) and specific gas production (SGP) exert an important role in methanogenic phase description.

  11. Maximum organic loading rate for the single-stage wet anaerobic digestion of food waste.

    Science.gov (United States)

    Nagao, Norio; Tajima, Nobuyuki; Kawai, Minako; Niwa, Chiaki; Kurosawa, Norio; Matsuyama, Tatsushi; Yusoff, Fatimah Md; Toda, Tatsuki

    2012-08-01

    Anaerobic digestion of food waste was conducted at high OLR from 3.7 to 12.9 kg-VS m(-3) day(-1) for 225 days. Periods without organic loading were arranged between the each loading period. Stable operation at an OLR of 9.2 kg-VS (15.0 kg-COD) m(-3) day(-1) was achieved with a high VS reduction (91.8%) and high methane yield (455 mL g-VS-1). The cell density increased in the periods without organic loading, and reached to 10.9×10(10) cells mL(-1) on day 187, which was around 15 times higher than that of the seed sludge. There was a significant correlation between OLR and saturated TSS in the sludge (y=17.3e(0.1679×), r(2)=0.996, P<0.05). A theoretical maximum OLR of 10.5 kg-VS (17.0 kg-COD) m(-3) day(-1) was obtained for mesophilic single-stage wet anaerobic digestion that is able to maintain a stable operation with high methane yield and VS reduction.

  12. Hydrolysis and thermophilic anaerobic digestion of sewage sludge and organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Del Borghi, A.; Converti, A.; Palazzi, E.; Del Borghi, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, Genoa University, Via Opera Pia 15, 16145 Genoa (Italy)

    1999-06-01

    An attempt is presented and discussed to adapt a well-known process successfully employed in the U.S.A. for the simultaneous treatment of the organic fraction of municipal solid waste (MSWOF) and sewage sludge to the particular situation of water works in Italy. It consists of preliminary domestic grinding of MSWOF, its discharge into the sewer, screening, and final digestion of the resulting residue together with sewage sludge. In order to avoid extension work of the present activated sludge sections necessary to face the organic load increase, a fine screening is necessary, while the efficiency of anaerobic digestion can be improved by shifting the system from mesophilic (37 C) to thermophilic (55 C) conditions. The effects of thermal, chemical, and biological pretreatments of both MSWOF and sewage sludge on methane, carbon dioxide, and biogas productions are investigated either separately or jointly. During these pretreatments, volatile suspended solid (VSS) concentration remarkably decreased while soluble chemical oxygen demand (COD) increased as the result of the progressive hydrolysis of the polymeric materials present in the feed. Finally, the kinetic parameters of the hydrolysis of these materials are estimated and compared in order to provide useful information on the factors limiting the anaerobic digestion as well as to suggest the best way to carry out the process on a large scale. (orig.) With 8 figs., 7 tabs., 20 refs.

  13. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    Science.gov (United States)

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated.

  14. Biogas by two-stage microbial anaerobic and semi-continuous digestion of Chinese cabbage waste

    Institute of Scientific and Technical Information of China (English)

    Xiaoying Dong; Lijie Shao; Yan Wang; Wei Kou; Yanxin Cao; Dalei Zhang

    2015-01-01

    Anaerobic digestion of Chinese cabbage waste was investigated through a pilot-scale two-stage digester at a mesophilic temperature of 37 °C. In the acidification digester, the main product was acetic acid, with the maxi-mum concentration of 4289 mg·L-1 on the fourth day, accounting for 50.32%of total volatile fatty acids. The oxidation reduction potential (ORP) and NH4+-N level decreased gradual y with hydraulic retention time (HRT) of acidification. In the second digestion phase, the maximum methanogenic bacterial concentration reached 9.6 × 1010 ml-1 at the organic loading rate (OLR) of 3.5–4 kg VS·m-3, with corresponding HRT of 12–16 days. Accordingly, the optimal biogas production was 0.62 m3·(kg VS)-1, with methane content of 65%–68%. ORP and NH4+-N levels in the methanizer remained between-500 and-560 mV and 2000–4500 mg·L-1, respec-tively. Methanococcus and Methanosarcina served as the main methanogens in the anaerobic digester.

  15. Evaluation the anaerobic hydrolysis acidification stage of kitchen waste by pH regulation.

    Science.gov (United States)

    Wang, Yaya; Zang, Bing; Li, Guoxue; Liu, Yu

    2016-07-01

    This study analyzed the composition and characteristic of kitchen waste (KW) from closed cleaning station of Chaoyang District, Beijing. It was featured by high vegetables and peels contents. This study investigated effect of pH regulation and uncontrolled pH (CK) on the lab-scale anaerobic hydrolysis acidification stage of KW. The optimal adjusting mode by NaOH (including dosage and frequency) was evaluated according to indexes of pH, VFAs, NH4(+)-N, TS, VS, TS/VS, TS and VS removal rate. The treatment 4 as first two days adjusting per 16h and then one time per day at pH 7 was chosen as the optimal mode with high VFAs content(47.31g/L), TS and VS removal rate (42.95% and 54.01%, respectively), low adjusting frequency, fewer dosage and practical operability. Thus, adjusting mode of treatment 4 could be considered using in anaerobic hydrolysis acidification stage on engineering.

  16. Anaerobic digestion of food waste stabilized by lime mud from papermaking process.

    Science.gov (United States)

    Zhang, Jishi; Wang, Qinqing; Zheng, Pengwei; Wang, Yusong

    2014-10-01

    The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Two-stage anaerobic fermentation of organic waste in CSTR and UFAF-reactors.

    Science.gov (United States)

    Held, Christof; Wellacher, Martin; Robra, Karl-Heinz; Gübitz, Georg M

    2002-01-01

    The mechanically separated liquid fraction of organic waste from households was used as a substrate for anaerobic fermentation. A two-step system consisting of a 2001 continuously stirred tank reactor (CSTR) and a 501 upflow anaerobic filter filled with glass foam pearls was constructed. The CSTR was operated for 5 months with a loading rate of 9.8 kg CSB m(-3) day(-1). At a resulting hydraulic retention time (HRT) of 24 days, 68% COD was degraded and a gas productivity of 4.0 m3 m(-3) day(-1) was achieved. Further digestion of the CSTR output was separately optimised in a 20 l-UFAF and based on these results a 50 l-UFAF was connected to the CSTR. At a resulting hydraulic retention time (HRT) of 6 days 38% COD was degraded and a gas productivity of 1.8 m3 m(-3) day(-1) was achieved with the 50 l-UFAF. Thus, the overall degradation efficiency of the two-phase system was 80%. The methane content (61%) of the biogas produced in the 50 l-UF

  18. Effect of organic loading rate during anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Dhar, Hiya; Kumar, Pradeep; Kumar, Sunil; Mukherjee, Somnath; Vaidya, Atul N

    2016-10-01

    The effect of chemical oxygen demand (COD) and volatile solids (VS) on subsequent methane (CH4) production during anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) was studied in a laboratory-scale digester. The experiment was performed in 2L anaerobic digester under different experimental conditions using different input mass co-digested with inoculum and organic loading rate (OLR) for 27days at 38±2°C. Three digesters (digesters 1, 2 and 3) were operated at initial loading of 5.1, 10.4 and 15.2g/L CODS per batch which were reduced to 77.9% and 84.2%, respectively. Cumulative biogas productions were 9.3, 10.7 and 17.7L in which CH4 yields were 84.3, 101.0 and 168.4mL/gVS removal in digesters 1, 2, and 3, respectively. The observed COD removal was found to be influenced on variation in CH4 production. Co-efficient of determination (R(2)) was 0.67 and 0.74 in digesters 1 and 2, respectively.

  19. Anaerobic digestion of pre-fermented potato peel wastes for methane production.

    Science.gov (United States)

    Liang, Shaobo; McDonald, Armando G

    2015-12-01

    This study investigated the feasibility of anaerobic digestion (AD) of potato peel waste (PPW) and its lactic acid fermentation residue (PPW-FR) for methane (CH4) production. The experimental results showed that about 60-70% CH4 content was obtained. The digester using PPW-FR as feedstock exhibited better performance and produced a highest cumulative CH4 production of 273 L/kg VS fed, followed by 239 L/kg VS fed using PPW under the same conditions. However, with increasing solid loadings of PPW-FR feedstock from 6.4% to 9.1%, the CH4 production was inhibited. The generation, accumulation, and degradation of volatile fatty acids (VFAs) in digesters were also investigated in this research. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Microbiological corrosion in aerobic and anaerobic waste purification plants: safety and efficiency problems

    Energy Technology Data Exchange (ETDEWEB)

    Perego, P. [ISTIC - Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa, Via Opera Pia 15-16145 Genoa (Italy); Fabiano, B. [ISTIC - Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa, Via Opera Pia 15-16145 Genoa (Italy); Pastorino, R. [ISTIC - Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa, Via Opera Pia 15-16145 Genoa (Italy); Randi, G. [ISTIC - Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa, Via Opera Pia 15-16145 Genoa (Italy)

    1997-07-01

    Carbon steels and stainless steels are largely employed in order to build up biological purification systems of urban and industrial waste. The former are applied in building up tanks, vessels and pipes; the latter are employed in building up operator machines and appliances. This paper presents a study of the corrosion behaviour of these materials in anaerobic and aerobic environments. Tests have been carried out by continuous immersion in a biologic liquid with mixed flora. The observation of samples taken at different times of exposure has given information of great interest of application, especially about the mechanisms of localized corrosion phenomena and about the behaviour of these materials in function. Besides the presented study shows original possibilities for the assessment of the corrosion phenomenon that can be adopted and developed further still. (orig.). With 7 figs., 4 tabs.

  1. Environmental assessment of energy and waste systems based on anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Rehl, Torsten

    2013-08-01

    The results of the studies show that biogas production brings about many or environmental improvements compared to energy generation based on fossil sources when designed and managed properly. Environmental advantages are found for GWP (Global Warming Potential) and energy consumption, disadvantages however for EP (Eutrophication Potential), AP (Acidification Potential) and POCP (Photochemical Ozone Creation Potential). However the large amount of technologies and measures indicate that there is a large potential to reduce the environmental impacts. Another finding is that all life cycle phases and subsystems must be carefully considered, as no single dominating item or aspect in the life cycle can be identified. The most environmentally relevant phases are found to be storage, treatment and field application of manure and digestate. This result is to a large part due to the emission of ammonia, nitrous oxide and nitrate. It can therefore be concluded that from a lifecycle perspective, control and mitigation of nitrogen related emissions will be of utmost importance in the future to improve the environmental performance of biogas systems. Considerable emission reduction potentials are exposed when proper technological modifications (e.g. storage covers, filter technologies, digestate treatment or field application technologies) or adopted management practices (early soil incorporation of digestate) are applied. The environmental analysis also shows that whenever possible the focus of anaerobic digestion should be on the use of organic residues from households, agriculture or food industry instead of using energy crops. In this case conventional waste management systems are replaced and manifold positive effects of anaerobic digestion such as waste stabilization, nutrient recycling and energy generation emerge.

  2. Zero valent iron simultaneously enhances methane production and sulfate reduction in anaerobic granular sludge reactors.

    Science.gov (United States)

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-05-15

    Zero valent iron (ZVI) packed anaerobic granular sludge reactors have been developed for improved anaerobic wastewater treatment. In this work, a mathematical model is developed to describe the enhanced methane production and sulfate reduction in anaerobic granular sludge reactors with the addition of ZVI. The model is successfully calibrated and validated using long-term experimental data sets from two independent ZVI-enhanced anaerobic granular sludge reactors with different operational conditions. The model satisfactorily describes the chemical oxygen demand (COD) removal, sulfate reduction and methane production data from both systems. Results show ZVI directly promotes propionate degradation and methanogenesis to enhance methane production. Simultaneously, ZVI alleviates the inhibition of un-dissociated H2S on acetogens, methanogens and sulfate reducing bacteria (SRB) through buffering pH (Fe(0) + 2H(+) = Fe(2+) + H2) and iron sulfide precipitation, which improve the sulfate reduction capacity, especially under deterioration conditions. In addition, the enhancement of ZVI on methane production and sulfate reduction occurs mainly at relatively low COD/ [Formula: see text] ratio (e.g., 2-4.5) rather than high COD/ [Formula: see text] ratio (e.g., 16.7) compared to the reactor without ZVI addition. The model proposed in this work is expected to provide support for further development of a more efficient ZVI-based anaerobic granular system.

  3. Anaerobic co-digestion plants for the revaluation of agricultural waste: Sustainable location sites from a GIS analysis.

    Science.gov (United States)

    Villamar, Cristina Alejandra; Rivera, Diego; Aguayo, Mauricio

    2016-04-01

    The aim of this study was to establish sustainably feasible areas for the implementation of anaerobic co-digestion plants for agricultural wastes (cattle/swine slurries and cereal crop wastes). The methodology was based on the use of geographic information systems (GIS), the analytic hierarchy process (AHP) and map algebra generated from hedges related to environmental, social and economic constraints. The GIS model obtained was applied to a region of Chile (Bío Bío Region) as a case study showing the energy potential (205 MW-h) of agricultural wastes (swine/cattle manures and cereal crop wastes) and thereby assessing its energy contribution (3.5%) at country level (Chile). From this model, it was possible to spatially identify the influence of each factor (environmental, economic and social) when defining suitable areas for the siting of anaerobic co-digestion plants. In conclusion, GIS-based models establish appropriate areas for the location of anaerobic co-digestion plants in the revaluation of agricultural waste from the production of energy through biogas production.

  4. Anaerobic co-digestion of municipal food waste and sewage sludge: A comparative life cycle assessment in the context of a waste service provision.

    Science.gov (United States)

    Edwards, Joel; Othman, Maazuza; Crossin, Enda; Burn, Stewart

    2017-01-01

    This study used life cycle assessment to evaluate the environmental impact of anaerobic co-digestion (AcoD) and compared it against the current waste management system in two case study areas. Results indicated AcoD to have less environmental impact for all categories modelled excluding human toxicity, despite the need to collect and pre-treat food waste separately. Uncertainty modelling confirmed that AcoD has a 100% likelihood of a smaller global warming potential, and for acidification, eutrophication and fossil fuel depletion AcoD carried a greater than 85% confidence of inducing a lesser impact than the current waste service.

  5. Elucidating microbial community adaptation to anaerobic co-digestion of fats, oils, and grease and food waste.

    Science.gov (United States)

    Amha, Yamrot M; Sinha, Pooja; Lagman, Jewls; Gregori, Matt; Smith, Adam L

    2017-10-15

    Despite growing interest in co-digestion and demonstrated process improvements (e.g., enhanced stability and biogas production), few studies have evaluated how co-digestion impacts the anaerobic digestion (AD) microbiome. Three sequential bench-scale respirometry experiments were conducted at thermophilic temperature (50 °C) with various combinations of primary sludge (PS); thickened waste activated sludge (TWAS); fats, oils, and grease (FOG); and food waste (FW). Two additional runs were then performed to evaluate microbial inhibition at higher organic fractions of FOG (30-60% volatile solids loading (VSL; v/v)). Co-digestion of PS, TWAS, FOG, and FW resulted in a 26% increase in methane production relative to digestion of PS and TWAS. A substantial lag time was observed in biogas production for vessels with FOG addition that decreased by more than half in later runs, likely due to adaptation of the microbial community. 30% FOG with 10% FW showed the highest increase in methane production, increasing 53% compared to digestion of PS and TWAS. FOG addition above 50% VSL was found to be inhibitory with and without FW addition and resulted in volatile fatty acid (VFA) accumulation. Methane production was linked with high relative activity and abundance of syntrophic fatty-acid oxidizers alongside hydrogenotrophic methanogens, signaling the importance of interspecies interactions in AD. Specifically, relative activity of Syntrophomonas was significantly correlated with methane production. Further, methane production increased over subsequent runs along with methyl coenzyme M reductase (mcrA) gene expression, a functional gene in methanogens, suggesting temporal adaptation of the microbial community to co-digestion substrate mixtures. The study demonstrated the benefits of co-digestion in terms of performance enhancement and enrichment of key active microbial populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study

    Science.gov (United States)

    Wang, Qinghong; Liang, Ying; Zhao, Peng; Li, Qing X.; Guo, Shaohui; Chen, Chunmao

    2016-12-01

    Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge.

  7. Process stability and microbial community structure in anaerobic hydrogen-producing microflora from food waste containing kimchi.

    Science.gov (United States)

    Jo, Ji Hye; Jeon, Che Ok; Lee, Dae Sung; Park, Jong Moon

    2007-09-15

    Hydrogen production by the dark fermentation of food wastes is an economic and environmentally friendly technology to produce the clean energy source as well as to treat the problematic wastes. However, the long-term operations of the continuous anaerobic reactor for fermentative hydrogen production were frequently unstable. In this study, the structure of microbial community within the anaerobic reactor during unstable hydrogen production was examined by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) techniques. The changes in microbial community from H(2)-producing Clostridium spp. to lactic acid-producing Lactobacillus spp. were well coincident with the unexpected process failures and the changes of metabolites concentrations in the effluent of the anaerobic reactor. As the rate of hydrogen production decreased, effluent lactic acid concentration increased. Low rate of hydrogen production and changes in microbial community were related to the 'kimchi' content and storage temperature of food waste feed solution. After low temperature control of the storage tank of the feed solution, any significant change in microbial community within the anaerobic reactor did not occur and the hydrogen production was very stably maintained for a long time.

  8. Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study.

    Science.gov (United States)

    Wang, Qinghong; Liang, Ying; Zhao, Peng; Li, Qing X; Guo, Shaohui; Chen, Chunmao

    2016-12-01

    Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge.

  9. Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study

    Science.gov (United States)

    Wang, Qinghong; Liang, Ying; Zhao, Peng; Li, Qing X.; Guo, Shaohui; Chen, Chunmao

    2016-01-01

    Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge. PMID:27905538

  10. Heterologous production of Pseudomonas aeruginosa rhamnolipid under anaerobic conditions for microbial enhanced oil recovery.

    Science.gov (United States)

    Zhao, F; Shi, R; Zhao, J; Li, G; Bai, X; Han, S; Zhang, Y

    2015-02-01

    The ex situ application of rhamnolipid to enhance oil recovery is costly and complex in terms of rhamnolipid production and transportation, while in situ production of rhamnolipid is restricted by the oxygen-deficient environments of oil reservoirs. To overcome the oxygen-limiting conditions and to circumvent the complex regulation of rhamnolipid biosynthesis in Pseudomonas aeruginosa, an engineered strain Pseudomonas stutzeri Rhl was constructed for heterologous production of rhamnolipid under anaerobic conditions. The rhlABRI genes for rhamnolipid biosynthesis were cloned into a facultative anaerobic strain Ps. stutzeri DQ1 to construct the engineered strain Rhl. Anaerobic production of rhamnolipid was confirmed by thin layer chromatography and Fourier transform infrared analysis. Rhamnolipid product reduced the air-water surface tension to 30.3 mN m(-1) and the oil-water interfacial tension to 0.169 mN m(-1). Rhl produced rhamnolipid of 1.61 g l(-1) using glycerol as the carbon source. Rhl anaerobic culture emulsified crude oil up to EI24 ≈ 74. An extra 9.8% of original crude oil was displaced by Rhl in the core flooding test. Strain Rhl achieved anaerobic production of rhamnolipid and worked well for enhanced oil recovery in the core flooding model. The rhamnolipid produced by Rhl was similar to that of the donor strain SQ6. This is the first study to achieve anaerobic and heterologous production of rhamnolipid. Results demonstrated the potential feasibility of Rhl as a promising strain to enhance oil recovery through anaerobic production of rhamnolipid. © 2014 The Society for Applied Microbiology.

  11. Overcoming the bottlenecks of anaerobic digestion of olive mill solid waste by two-stage fermentation.

    Science.gov (United States)

    Stoyanova, Elitza; Lundaa, Tserennyam; Bochmann, Günther; Fuchs, Werner

    2017-02-01

    Two-stage anaerobic digestion (AD) of two-phase olive mill solid waste (OMSW) was applied for reducing the inhibiting factors by optimizing the acidification stage. Single-stage AD and co-fermentation with chicken manure were conducted coinstantaneous for direct comparison. Degradation of the polyphenols up to 61% was observed during the methanogenic stage. Nevertheless the concentration of phenolic substances was still high; the two-stage fermentation remained stable at OLR 1.5 kgVS/m³day. The buffer capacity of the system was twice as high, compared to the one-stage fermentation, without additives. The two-stage AD was a combined process - thermophilic first stage and mesophilic second stage, which pointed out to be the most profitable for AD of OMSW for the reduced hydraulic retention time (HRT) from 230 to 150 days, and three times faster than the single-stage and the co-fermentation start-up of the fermentation. The optimal HRT and incubation temperature for the first stage were determined to four days and 55°C. The performance of the two-stage AD concerning the stability of the process was followed by the co-digestion of OMSW with chicken manure as a nitrogen-rich co-substrate, which makes them viable options for waste disposal with concomitant energy recovery.

  12. Anaerobic Codigestion of Municipal Wastewater Treatment Plant Sludge with Food Waste: A Case Study

    Science.gov (United States)

    Rajendram, William

    2016-01-01

    The aim of this study was to assess the effects of the codigestion of food manufacturing and processing wastes (FW) with sewage sludge (SS), that is, municipal wastewater treatment plant primary sludge and waste activated sludge. Bench scale mesophilic anaerobic reactors were fed intermittently with varying ratio of SS and FW and operated at a hydraulic retention time of 20 days and organic loading of 2.0 kg TS/m3·d. The specific biogas production (SBP) increased by 25% to 50% with the addition of 1%–5% FW to SS which is significantly higher than the SBP from SS of 284 ± 9.7 mLN/g VS added. Although the TS, VS, and tCOD removal slightly increased, the biogas yield and methane content improved significantly and no inhibitory effects were observed as indicated by the stable pH throughout the experiment. Metal screening of the digestate suggested the biosolids meet the guidelines for use as a soil conditioner. Batch biochemical methane potential tests at different ratios of SS : FW were used to determine the optimum ratio using surface model analysis. The results showed that up to 47-48% FW can be codigested with SS. Overall these results confirm that codigestion has great potential in improving the methane yield of SS. PMID:27689091

  13. Anaerobic Digestion of Laminaria japonica Waste from Industrial Production Residues in Laboratory- and Pilot-Scale

    Directory of Open Access Journals (Sweden)

    Yann Nicolas Barbot

    2015-09-01

    Full Text Available The cultivation of macroalgae to supply the biofuel, pharmaceutical or food industries generates a considerable amount of organic residue, which represents a potential substrate for biomethanation. Its use optimizes the total resource exploitation by the simultaneous disposal of waste biomaterials. In this study, we explored the biochemical methane potential (BMP and biomethane recovery of industrial Laminaria japonica waste (LJW in batch, continuous laboratory and pilot-scale trials. Thermo-acidic pretreatment with industry-grade HCl or industrial flue gas condensate (FGC, as well as a co-digestion approach with maize silage (MS did not improve the biomethane recovery. BMPs between 172 mL and 214 mL g−1 volatile solids (VS were recorded. We proved the feasibility of long-term continuous anaerobic digestion with LJW as sole feedstock showing a steady biomethane production rate of 173 mL g−1 VS. The quality of fermentation residue was sufficient to serve as biofertilizer, with enriched amounts of potassium, sulfur and iron. We further demonstrated the upscaling feasibility of the process in a pilot-scale system where a CH4 recovery of 189 L kg−1 VS was achieved and a biogas composition of 55% CH4 and 38% CO2 was recorded.

  14. Feasibility of anaerobic co-digestion of pig waste and paper sludge.

    Science.gov (United States)

    Parameswaran, Prathap; Rittmann, Bruce E

    2012-11-01

    Pig waste (PW) and paper sludge (PS) possess complementary properties that can be combined for successful anaerobic digestion. Biochemical methane potential (BMP) tests revealed that a PW:PS 3:1 (v/v) ratio had the highest normalized CH(4)-COD removal (54%), while PS had the lowest value (11%) and PW had 44%. Batch BMP tests revealed a significant decrease in lag times for methane production in the order of PW:PS 1:3 (14 days)waste streams: 0.004 d(-1) (PS)<0.02 d(-1) (PW)<0.024 d(-1) (PW:PS 3:1)<0.03 d(-1) (PW:PS 1:1)<0.05 d(-1) (PW:PS 1:3). Semi-continuous reactors performing co-digestion of PW and PS at a 2:1 ratio showed 1.5 times higher methane production than baseline PW-only reactors, confirming the BMP results. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Volatile fatty acids production from anaerobic treatment of cassava waste water: effect of temperature and alkalinity.

    Science.gov (United States)

    Hasan, Salah Din Mahmud; Giongo, Citieli; Fiorese, Mônica Lady; Gomes, Simone Damasceno; Ferrari, Tatiane Caroline; Savoldi, Tarcio Enrico

    2015-01-01

    The production of volatile fatty acids (VFAs), intermediates in the anaerobic degradation process of organic matter from waste water, was evaluated in this work. A batch reactor was used to investigate the effect of temperature, and alkalinity in the production of VFAs, from the fermentation of industrial cassava waste water. Peak production of total volatile fatty acids (TVFAs) was observed in the first two days of acidogenesis. A central composite design was performed, and the highest yield (3400 mg L(-1) of TVFA) was obtained with 30°C and 3 g L(-1) of sodium bicarbonate. The peak of VFA was in 45 h (pH 5.9) with a predominance of acetic (63%) and butyric acid (22%), followed by propionic acid (12%). Decreases in amounts of cyanide (12.9%) and chemical oxygen demand (21.6%) were observed, in addition to the production of biogas (0.53 cm(3) h(-1)). The process was validated experimentally and 3400 g L(-1) of TVFA were obtained with a low relative standard deviation.

  16. Uncoupling of liquid and solid retention times in anaerobic digestion of catering wastes.

    Science.gov (United States)

    Climenhaga, M A; Banks, C J

    2008-01-01

    Source-separated food wastes collected from a university campus catering facility were processed in bench-scale anaerobic digesters. The feedstock contained a varied mix of fruits, vegetables, meats and fried foods. Two modes of digestion were compared. The first was hydraulic flush (HF) mode, in which liquids were flushed through the reactor on a retention time of 25 days while solids were maintained on an extended retention time of over 150 days. The converse was a solids wastage (SW) mode, in which liquid retention time was over 150 days, and solids were wasted to maintain a retention time of 25 days. SW reactors exhibited methanogenic failure after approximately 45 days. HF reactors, in contrast, maintained stable digestion for a period of 100 days, and were robust enough to recover from a thermal shock applied over a three-day period in which the temperature was increased from 35 degrees C to 50 degrees C between days 105-108 of the experiment. Stable operation was regained by day 139 and continued until the end of the run on day 150.

  17. Anaerobic digestion of fruit and vegetable processing wastes for biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Viswanath, P.; Sumithra Devi, S.; Nand, K. (Central Food Technological Research Inst., Mysore (IN))

    1992-01-01

    The effect of feeding different fruit and vegetable wastes, mango, pineapple, tomato, jackfruit, banana and orange, was studied in a 60-litre digester by cycling each waste every fifth day in order to operate the digester as and when there was supply of feed. The characteristics of the anaerobically digested fluid and digester performance in terms of biogas production were determined at different loading rates (LR) and at different hydraulic retention times (HRT) and the maximum biogas yield of 0.6 m{sup 3}/kg VS added was achieved at a 20-day HRT and 40 kg TS m{sup -3}day{sup -1} loading rate. The hourly gas production was observed in the digesters operated at 16 and 24 days HRT. The major yield (74.5%) of gas was produced within 12h of feeding at a 16-day HRT whereas at a 24-day HRT only 59.03% of the total gas could be obtained at this time. (author).

  18. Anaerobic Digestion of Laminaria japonica Waste from Industrial Production Residues in Laboratory- and Pilot-Scale

    Science.gov (United States)

    Barbot, Yann Nicolas; Thomsen, Claudia; Thomsen, Laurenz; Benz, Roland

    2015-01-01

    The cultivation of macroalgae to supply the biofuel, pharmaceutical or food industries generates a considerable amount of organic residue, which represents a potential substrate for biomethanation. Its use optimizes the total resource exploitation by the simultaneous disposal of waste biomaterials. In this study, we explored the biochemical methane potential (BMP) and biomethane recovery of industrial Laminaria japonica waste (LJW) in batch, continuous laboratory and pilot-scale trials. Thermo-acidic pretreatment with industry-grade HCl or industrial flue gas condensate (FGC), as well as a co-digestion approach with maize silage (MS) did not improve the biomethane recovery. BMPs between 172 mL and 214 mL g−1 volatile solids (VS) were recorded. We proved the feasibility of long-term continuous anaerobic digestion with LJW as sole feedstock showing a steady biomethane production rate of 173 mL g−1 VS. The quality of fermentation residue was sufficient to serve as biofertilizer, with enriched amounts of potassium, sulfur and iron. We further demonstrated the upscaling feasibility of the process in a pilot-scale system where a CH4 recovery of 189 L kg−1 VS was achieved and a biogas composition of 55% CH4 and 38% CO2 was recorded. PMID:26393620

  19. Effects of alkalinity sources on the stability of anaerobic digestion from food waste.

    Science.gov (United States)

    Chen, Shujun; Zhang, Jishi; Wang, Xikui

    2015-11-01

    This study investigated the effects of some alkalinity sources on the stability of anaerobic digestion (AD) from food waste (FW). Four alkalinity sources, namely lime mud from papermaking (LMP), waste eggshell (WES), CaCO3 and NaHCO3, were applied as buffer materials and their stability effects were evaluated in batch AD. The results showed that LMP and CaCO3 had more remarkable effects than NaHCO3 and WES on FW stabilization. The methane yields were 120.2, 197.0, 156.2, 251.0 and 194.8 ml g(-1) VS for the control and synergistic digestions of CaCO3, NaHCO3, LMP and WES added into FW, respectively. The corresponding final alkalinity reached 5906, 7307, 9504, 7820 and 6782 mg l(-1), while the final acidities were determined to be 501, 200, 50, 350 and 250 mg l(-1), respectively. This indicated that the synergism between alkalinity and inorganic micronutrients from different alkalinity sources played an important role in the process stability of AD from FW.

  20. Anaerobic Codigestion of Municipal Wastewater Treatment Plant Sludge with Food Waste: A Case Study

    Directory of Open Access Journals (Sweden)

    Zubayeda Zahan

    2016-01-01

    Full Text Available The aim of this study was to assess the effects of the codigestion of food manufacturing and processing wastes (FW with sewage sludge (SS, that is, municipal wastewater treatment plant primary sludge and waste activated sludge. Bench scale mesophilic anaerobic reactors were fed intermittently with varying ratio of SS and FW and operated at a hydraulic retention time of 20 days and organic loading of 2.0 kg TS/m3·d. The specific biogas production (SBP increased by 25% to 50% with the addition of 1%–5% FW to SS which is significantly higher than the SBP from SS of 284±9.7 mLN/g VS added. Although the TS, VS, and tCOD removal slightly increased, the biogas yield and methane content improved significantly and no inhibitory effects were observed as indicated by the stable pH throughout the experiment. Metal screening of the digestate suggested the biosolids meet the guidelines for use as a soil conditioner. Batch biochemical methane potential tests at different ratios of SS : FW were used to determine the optimum ratio using surface model analysis. The results showed that up to 47-48% FW can be codigested with SS. Overall these results confirm that codigestion has great potential in improving the methane yield of SS.

  1. Microwave Enhanced Freeze Drying of Solid Waste Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of technology for Microwave Enhanced Freeze Drying of Solid Waste (MEFDSW) is proposed. The present state of the art for solid waste stabilization using...

  2. Effect of Solids Retention Time on the Denitrification Potential of Anaerobically Digested Swine Waste

    Science.gov (United States)

    Kinyua, Maureen Njoki

    Three continuously stirred tank reactors (CSTR) were operated in semi continuous mode treating swine waste using anaerobic digestion. The reactors were used to test the effect of solid retention time (SRT) on CH4 yield, total ammonia nitrogen (TAN) concentrations, % volatile solids (VS), chemical oxygen demand (COD) and volatile fatty acids (VFA) removal, readily biodegradable COD concentration and the denitrification potential for the effluent in a biological nutrient removal (BNR) system. During Phase I of the study, the three reactors were operated at the same 28 day SRT for 16 weeks. SRTs were then changed during the 12 week Phase II period. The SRTs studied were 14, 21 and 28 days, with the same organic loading rate (OLR) of 1.88 ± 0.2 kg VS/ m3-day. The reactor with the lowest SRT (14 days) had the highest VS and VFA removal at 73.6 and 67.6% and lowest TAN concentration at 0.78 g NH4+-N/L, followed by the 21 day and 28 day reactors. This was likely due to the fast microbial growth rates and substrate utilization rates in this reactor compared with the other two. The 14 day reactor had the highest CH4 yield at 0.33 m3CH 4/kg VS added and readily biodegradable COD concentration at 0.93 COD/L. The variations in CH4 yield and readily biodegradable COD concentrations between the three reactors were not statistically significant. Denitrification potential for the reactors was 1.20, 0.73 and 0.56 g COD/g N for 14, 21 and 28 day reactors, respectively, and the differences were statistically significant. None of the reactors achieved a denitrification potential of 5 g COD/g N, the amount required to use effluent of anaerobically digested swine waste as an internal carbon source in a BNR. This was attributed to operating conditions such as freezing and thawing of the raw swine waste that maximized CH4 yield and lowered the readily biodegradable COD concentration. In addition the 14 day reactor had low TAN concentrations thus increasing the denitrification potential

  3. Anaerobic treatment of complex wastewater and waste activated sludge - Appl. of an upflow anaerobic solid removal (UASR).

    NARCIS (Netherlands)

    Zeeman, G.; Sanders, W.T.M.; Wang, K.Y.; Lettinga, G.

    1997-01-01

    The application of one phase anaerobic wastewater systems for the treatment of complex wastewaters containing high amounts of suspended solids or lipids is usually limited by accumulation of these compounds in the sludge bed. This accumulation reduces the solid retention time and methanogenic activi

  4. Characterizing the variability of food waste quality: A need for efficient valorisation through anaerobic digestion.

    Science.gov (United States)

    Fisgativa, Henry; Tremier, Anne; Dabert, Patrick

    2016-04-01

    In order to determine the variability of food waste (FW) characteristics and the influence of these variable values on the anaerobic digestion (AD) process, FW characteristics from 70 papers were compiled and analysed statistically. Results indicated that FW characteristics values are effectively very variable and that 24% of these variations may be explained by the geographical origin, the type of collection source and the season of the collection. Considering the whole range of values for physicochemical characteristics (especially volatile solids (VS), chemical oxygen demand (COD) and biomethane potential (BMP)), FW show good potential for AD treatment. However, the high carbohydrates contents (36.4%VS) and the low pH (5.1) might cause inhibitions by the rapid acidification of the digesters. As regards the variation of FW characteristics, FW categories were proposed. Moreover, the adequacy of FW characteristics with AD treatment was discussed. Four FW categories were identified with critical characteristics values for AD performance: (1) the high dry matter (DM) and total ammonia nitrogen (TAN) content of FW collected with green waste, (2) the high cellulose (CEL) content of FW from the organic fraction of municipal solid waste, (3) the low carbon-to-nitrogen (C/N) ratio of FW collected during summer, (4) the high value of TAN and Na of FW from Asia. For these cases, an aerobic pre-treatment or a corrective treatment seems to be advised to avoid instabilities along the digestion. Finally, the results of this review-paper provide a data basis of values for FW characteristics that could be used for AD process design and environmental assessment.

  5. Analysis on carbon dioxide emission reduction during the anaerobic synergetic digestion technology of sludge and kitchen waste: Taking kitchen waste synergetic digestion project in Zhenjiang as an example.

    Science.gov (United States)

    Guo, Qia; Dai, Xiaohu

    2017-08-30

    With the popularization of municipal sewage treatment facilities, the improvement of sewage treatment efficiency and the deepening degree of sewage treatment, the sludge production of sewage plant has been sharply increased. Carbon emission during the process of municipal sewage treatment and disposal has become one of the important sources of greenhouse gases that cause greenhouse effect. How to reduce carbon dioxide emissions during sewage treatment and disposal process is of great significance for reducing air pollution. Kitchen waste and excess sludge, as two important organic wastes, once uses anaerobic synergetic digestion technology in the treatment process can on the one hand, avoid instability of sludge individual anaerobic digestion, improve sludge degradation rate and marsh gas production rate, and on the other hand, help increase the reduction of carbon dioxide emissions to a great extent. The paper uses material balance method, analyzes and calculates the carbon dioxide emissions from kitchen waste and sludge disposed by the anaerobic synergetic digestion technology, compares the anaerobic synergetic digestion technology with traditional sludge sanitary landfill technology and works out the carbon dioxide emission reductions after synergetic digestion. It takes the kitchen waste and sludge synergetic digestion engineering project of Zhenjiang city in Jiangsu province as an example, makes material balance analysis using concrete data and works out the carbon dioxide daily emission reductions. The paper analyzes the actual situation of emission reduction by comparing the data, and found that the synergetic digestion of kitchen waste and sludge can effectively reduce the carbon dioxide emission, and the reduction is obvious especially compared with that of sludge sanitary landfill, which has a certain effect on whether to promote the use of the technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Anaerobic co-digestion of food waste and septage – A waste to energy project in Nashik city

    Directory of Open Access Journals (Sweden)

    Meghanath Prabhu

    2015-04-01

    Full Text Available The samples for food waste (FW and septage were collected from six localities of Nashik city. Physical and chemical characterizations of the wastes were carried out. A Biomethanation potential (BMP assay was developed to determine the ultimate biodegradability and associated methane yield during the anaerobic methanogenic fermentation of organic substrates. BMP assays of individual substrate, FW and septage were carried out by taking into account the volatile solids/total solids (VS/TS ratio of each while keeping the inoculum’s VS constant. BMP of FW and septage mixture was carried out in different ratios (1:1, 1.5:1, 2:1, 1:1.5 and 1:2 to find the optimum mixing ratio for maximum biogas production. The average methane yield for different locality FW was found to be 503±17.6 ml/g VS and for septage it was 56 ±10.8 ml/g VS. Based on the above results, the total biogas yield and total methane yield for 10 tons of FW would be 2178 m3/d and 1306 m3/d respectively. The total biogas yield and total methane yield for 20 m3 of septage would be 65m3/d and 39m3/d respectively. From our co-digestion studies we also conclude that the mixture of FW to septage at 1:2 ratio gives 2896 m3/day of biogas. The role of septage is to provide essential trace elements that are required for methanogens.

  7. Batch and semi-continuous anaerobic digestion of food waste in a dual solid-liquid system.

    Science.gov (United States)

    Zhang, Cunsheng; Su, Haijia; Tan, Tianwei

    2013-10-01

    To avoid the inhibition from both of waste oil and high concentrations of cationic elements, anaerobic digestion of food waste in a dual solid-liquid (ADSL) system was examined in this present paper. Results from batch test indicated that a higher methane yield could be obtained in the ADSL system. The methane yield of food solid waste (FSW), food liquid waste (FLW) and raw food waste (RFW) were 643, 659 and 581 mL/g-VS, respectively. In semi-continuous anaerobic digestion, the optimum organic loading rates (OLR) for FSW, FLW and RFW were 9, 4 and 7 g-VS/L/d, respectively. The total methane production of RFW and ADSL systems, based on 1 kg-VS(RFW), were 405 and 460 L, respectively, indicating that the methane production increased by 13.6% in the ADSL system. The optimum C/N ratio, redistribution of metal element and lower content of waste oil in FSW explain the higher methane production.

  8. A financial feasibility model of gasification and anaerobic digestion waste-to-energy (WTE) plants in Saudi Arabia.

    Science.gov (United States)

    Hadidi, Laith A; Omer, Mohamed Mahmoud

    2017-01-01

    Municipal Solid Waste (MSW) generation in Saudi Arabia is increasingly growing at a fast rate, as it hurtles towards ever increasing urban development coupled with rapid developments and expanding population. Saudi Arabia's energy demands are also rising at a faster rate. Therefore, the importance of an integrated waste management system in Saudi Arabia is increasingly rising and introducing Waste to Energy (WTE) facilities is becoming an absolute necessity. This paper analyzes the current situation of MSW management in Saudi Arabia and proposes a financial model to assess the viability of WTE investments in Saudi Arabia in order to address its waste management challenges and meet its forecasted energy demands. The research develops a financial model to investigate the financial viability of WTE plants utilizing gasification and Anaerobic Digestion (AD) conversion technologies. The financial model provides a cost estimate of establishing both gasification and anaerobic digestion WTE plants in Saudi Arabia through a set of financial indicators, i.e. net present value (NPV), internal rate of return (IRR), modified internal rate of return (MIRR), profitability index (PI), payback period, discounted payback period, Levelized Cost of Electricity (LCOE) and Levelized Cost of Waste (LCOW). Finally, the analysis of the financial model reveals the main affecting factors of the gasification plants investment decision, namely: facility generation capacity, generated electricity revenue, and the capacity factor. Similarly, the paper also identifies facility waste capacity and the capacity factor as the main affecting factors on the AD plants' investment decision. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Economic and environmental analysis of four different configurations of anaerobic digestion for food waste to energy conversion using LCA for: a food service provider case study.

    Science.gov (United States)

    Franchetti, Matthew

    2013-07-15

    The US disposes of more than 34 million tons of food waste in landfills per year. As this food waste decomposes it generates methane gas and negatively contributes to global warming. Diverting theses organic food wastes from landfills and to emerging technologies will prevent these wastes and greenhouse gas emissions while at the same time generating a source renewable energy by collecting the emitted gases. From a waste prevention standpoint, instead of the food waste decomposing at local landfills, it is being converted into an energy source and the by-product may be used as a fertilizer (Fine and Hadas, 2012). The purpose of this study was to compare four different configurations of anaerobic digestion of organic waste to energy technologies from an economic, energy, and emissions standpoint using LCA via a case study at a large food services provider in Northwest Ohio, USA. The technologies studied included two-stage anaerobic digestion system using ultrasound pre-treating, two stage continuous combined thermophilic acidogenic hydrogenesis and mesophilic with recirculation of the digested sludge, long-term anaerobic digestion of food waste stabilized by trace elements, and single stage anaerobic digestion. Using LCA, these scenarios were compared to landfill disposal of the food waste. The findings from the case study indicated that implementing on-site waste to energy systems will result in lower operation costs and lower environmental impacts. In addition, a standardized environmental and economic comparison of competing food waste to energy technologies is provided. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Inhibiting excessive acidification using zero-valent iron in anaerobic digestion of food waste at high organic load rates.

    Science.gov (United States)

    Kong, Xin; Wei, Yonghong; Xu, Shuang; Liu, Jianguo; Li, Huan; Liu, Yili; Yu, Shuyao

    2016-07-01

    Excessive acidification occurs frequently in food waste (FW) anaerobic digestion (AD) due to the high carbon-to-nitrogen ratio of FW. In this study, zero-valent iron (ZVI) was applied to prevent the excessive acidification. All of the control groups, without ZVI addition (pH∼5.3), produced little methane (CH4) and had high volatile fatty acids/bicarbonate alkalinity (VFA/ALK). By contrast, at OLR of 42.32gVS/Lreactor, the pH of effluent from the reactors with 0.4g/gVSFWadded of ZVI increased to 7.8-8.2, VFA/ALK decreased to <0.1, and the final CH4 yield was ∼380mL/gVSFWadded, suggesting inhibition of excessive acidification. After adding powdered or scrap metal ZVI to the acidogenic reactors, the fractional content of butyric acid changed from 30-40% to 0%, while, that of acetic acid increased. These results indicate that adding ZVI to FW digestion at high OLRs could eliminate excessive acidification by promoting butyric acid conversion and enhancing methanogen activity.

  11. Evaluating enhanced sulfate reduction and optimized volatile fatty acids (VFA) composition in anaerobic reactor by Fe (III) addition.

    Science.gov (United States)

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-17

    Anaerobic reactors with ferric iron addition have been experimentally demonstrated to be able to simultaneously improve sulfate reduction and organic matter degradation during sulfate-containing wastewater treatment. In this work, a mathematical model is developed to evaluate the impact of ferric iron addition on sulfate reduction and organic carbon removal as well as the volatile fatty acids (VFA) composition in anaerobic reactor. The model is successfully calibrated and validated using independent long-term experimental data sets from the anaerobic reactor with Fe (III) addition under different operational conditions. The model satisfactorily describes the sulfate reduction, organic carbon removal and VFA production. Results show Fe (III) addition induces the microbial reduction of Fe (III) by iron reducing bacteria (IRB), which significantly enhances sulfate reduction by sulfate reducing bacteria (SRB) and subsequently changes the VFA composition to acetate-dominating effluent. Simultaneously, the produced Fe (II) from IRB can alleviate the inhibition of undissociated H2S on microorganisms through iron sulfide precipitation, resulting in further improvement of the performance. In addition, the enhancement on reactor performance by Fe (III) is found to be more significantly favored at relatively low organic carbon/SO4(2-) ratio (e.g., 1.0) than at high organic carbon/SO4(2-) ratio (e.g., 4.5). The Fe (III)-based process of this work can be easily integrated with a commonly used strategy for phosphorus recovery, with the produced sulfide being recovered and then deposited into conventional chemical phosphorus removal sludge (FePO4) to achieve FeS precipitation for phosphorus recovery while the required Fe (III) being acquired from the waste ferric sludge of drinking water treatment process, to enable maximum resource recovery/reuse while achieving high-rate sulfate removal.

  12. Global warming potential of material fractions occurring in source-separated organic household waste treated by anaerobic digestion or incineration under different framework conditions

    DEFF Research Database (Denmark)

    Naroznova, Irina; Møller, Jacob; Scheutz, Charlotte

    2016-01-01

    This study compared the environmental profiles of anaerobic digestion (AD) and incineration, in relation to global warming potential (GWP), for treating individual material fractions that may occur in source-separated organic household waste (SSOHW). Different framework conditions representative...

  13. Kinetic characterization of thermophilic and mesophilic anaerobic digestion for coffee grounds and waste activated sludge.

    Science.gov (United States)

    Li, Qian; Qiao, Wei; Wang, Xiaochang; Takayanagi, Kazuyuki; Shofie, Mohammad; Li, Yu-You

    2015-02-01

    This study was conducted to characterize the kinetics of an anaerobic process (hydrolysis, acetogenesis, acidogenesis and methanogenesis) under thermophilic (55 °C) and mesophilic (35 °C) conditions with coffee grounds and waste activated sludge (WAS) as the substrates. Special focus was given to the kinetics of propionic acid degradation to elucidate the accumulation of VFAs. Under the thermophilic condition, the methane production rate of all substrates (WAS, ground coffee and raw coffee) was about 1.5 times higher than that under the mesophilic condition. However, the effects on methane production of each substrate under the thermophilic condition differed: WAS increased by 35.8-48.2%, raw coffee decreased by 76.3-64.5% and ground coffee decreased by 74.0-57.9%. Based on the maximum reaction rate (Rmax) of each anaerobic stage obtained from the modified Gompertz model, acetogenesis was found to be the rate-limiting step for coffee grounds and WAS. This can be explained by the kinetics of propionate degradation under thermophilic condition in which a long lag-phase (more than 18 days) was observed, although the propionate concentration was only 500 mg/L. Under the mesophilic condition, acidogenesis and hydrolysis were found to be the rate-limiting step for coffee grounds and WAS, respectively. Even though reducing the particle size accelerated the methane production rate of coffee grounds, but did not change the rate-limiting step: acetogenesis in thermophilic and acidogenesis in mesophilic. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Biotic and abiotic processes contribute to successful anaerobic degradation of cyanide by UASB reactor biomass treating brewery waste water.

    Science.gov (United States)

    Novak, Domen; Franke-Whittle, Ingrid H; Pirc, Elizabeta Tratar; Jerman, Vesna; Insam, Heribert; Logar, Romana Marinšek; Stres, Blaž

    2013-07-01

    In contrast to the general aerobic detoxification of industrial effluents containing cyanide, anaerobic cyanide degradation is not well understood, including the microbial communities involved. To address this knowledge gap, this study measured anaerobic cyanide degradation and the rearrangements in bacterial and archaeal microbial communities in an upflow anaerobic sludge blanket (UASB) reactor biomass treating brewery waste water using bio-methane potential assays, molecular profiling, sequencing and microarray approaches. Successful biogas formation and cyanide removal without inhibition were observed at cyanide concentrations up to 5 mg l(-1). At 8.5 mg l(-1) cyanide, there was a 22 day lag phase in microbial activity, but subsequent methane production rates were equivalent to when 5 mg l(-1) was used. The higher cumulative methane production in cyanide-amended samples indicated that part of the biogas was derived from cyanide degradation. Anaerobic degradation of cyanide using autoclaved UASB biomass proceeded at a rate more than two times lower than when UASB biomass was not autoclaved, indicating that anaerobic cyanide degradation was in fact a combination of simultaneous abiotic and biotic processes. Phylogenetic analyses of bacterial and archaeal 16S rRNA genes for the first time identified and linked the bacterial phylum Firmicutes and the archaeal genus Methanosarcina sp. as important microbial groups involved in cyanide degradation. Methanogenic activity of unadapted granulated biomass was detected at higher cyanide concentrations than reported previously for the unadapted suspended biomass, making the aggregated structure and predominantly hydrogenotrophic nature of methanogenic community important features in cyanide degradation. The combination of brewery waste water and cyanide substrate was thus shown to be of high interest for industrial level anaerobic cyanide degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. A multi-criteria ranking of different technologies for the anaerobic digestion for energy recovery of the organic fraction of municipal solid wastes.

    Science.gov (United States)

    Karagiannidis, A; Perkoulidis, G

    2009-04-01

    This paper describes a conceptual framework and methodological tool developed for the evaluation of different anaerobic digestion technologies suitable for treating the organic fraction of municipal solid waste, by introducing the multi-criteria decision support method Electre III and demonstrating its related applicability via a test application. Several anaerobic digestion technologies have been proposed over the last years; when compared to biogas recovery from landfills, their advantage is the stability in biogas production and the stabilization of waste prior to final disposal. Anaerobic digestion technologies also show great adaptability to a broad spectrum of different input material beside the organic fraction of municipal solid waste (e.g. agricultural and animal wastes, sewage sludge) and can also be used in remote and isolated communities, either stand-alone or in conjunction to other renewable energy sources. Main driver for this work was the preliminary screening of such methods for potential application in Hellenic islands in the municipal solid waste management sector. Anaerobic digestion technologies follow different approaches to the anaerobic digestion process and also can include production of compost. In the presented multi-criteria analysis exercise, Electre III is implemented for comparing and ranking 5 selected alternative anaerobic digestion technologies. The results of a performed sensitivity analysis are then discussed. In conclusion, the performed multi-criteria approach was found to be a practical and feasible method for the integrated assessment and ranking of anaerobic digestion technologies by also considering different viewpoints and other uncertainties of the decision-making process.

  16. Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology

    Science.gov (United States)

    Gas-permeable membrane technology is useful to recover ammonia from manure. In this study, the technology was enhanced using aeration instead of alkali chemicals to increase pH and the ammonia recovery rate. Digested effluents from covered anaerobic swine lagoons containing 1375 to 2089 milligram am...

  17. Bioelectrochemical enhancement of methane production in low temperature anaerobic digestion at 10 °C

    NARCIS (Netherlands)

    Liu, Dandan; Zhang, Lei; Chen, Si; Buisman, Cees; Heijne, ter Annemiek

    2016-01-01

    Anaerobic digestion at low temperature is an attractive technology especially in moderate climates, however, low temperature results in low microbial activity and low rates of methane formation. This study investigated if bioelectrochemical systems (BESs) can enhance methane production from organ

  18. ANAEROBIC DDT BIOTRANSFORMATION: ENHANCEMENT BY APPLICATION OF SURFACTANTS AND LOW OXIDATION REDUCTION POTENTIAL

    Science.gov (United States)

    Enhancement of anaerobic DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane) biotransformation by mixed cultures was studied with application of surfactants and oxidation reduction potential reducing agents. Without amendments, DDT transformation resulted mainly in the pr...

  19. Microbial and nutritional regulation of high-solids anaerobic mono-digestion of fruit and vegetable wastes.

    Science.gov (United States)

    Mu, Hui; Li, Yan; Zhao, Yuxiao; Zhang, Xiaodong; Hua, Dongliang; Xu, Haipeng; Jin, Fuqiang

    2017-03-16

    The anaerobic digestion of single fruit and vegetable wastes (FVW) can be easily interrupted by rapid acidogenesis and inhibition of methanogen, and the digestion system tends to be particularly unstable at high solid content. In this study, the anaerobic digestion of FVW in batch experiments under mesophilic condition at a high solid concentration of 10% was successfully conducted to overcome the acidogenesis problem through several modifications. Firstly, compared with the conventional anaerobic sludge (CAS), the acclimated anaerobic granular sludge (AGS) was found to be a better inoculum due to its higher Archaea abundance. Secondly, waste activated sludge (WAS) was chosen to co-digest with FVW, because WAS had abundant proteins that could generate intermediate ammonium. The ammonium could neutralize the accumulated volatile fatty acids (VFAs) and prevent the pH value of the digestion system from rapidly decreasing. Co-digestion of FVW and WAS with TS ratio of 60:40 gave the highest biogas yield of 562 mL/g-VS and the highest methane yield of 362 mL/g-VS. Key parameters in the digestion process, including VFAs concentration, pH, enzyme activity, and microbial activity, were also examined.

  20. Analysis of the composition and formation of biogas produced during the processing of biological waste by anaerobic digestion technologies

    Directory of Open Access Journals (Sweden)

    Lubomír Hnilica

    2010-01-01

    Full Text Available This work compares the operating system of anaerobic fermentation of agricultural biogas plants with realization using biowaste. It deals with the operation system of anaerobic fermentation of agricultural biogas plants and implement an appropriate system to enable the use of biowaste. Based on the comparison of technological solutions and operational parameters of specific sites has been designed to allow the system biowaste were made a practical experiment to verify the assumption of increased biogas production. In experiments used substrates, which are industrially produced from the available bio-wastes, treated and then provide to operator of biogas plants. The work was carried out practical measurements to verify the production of biogas from different substrates. Utilize of nominal electric power using biowaste amounted up to 97.66%. Processing of such modified substrates in anaerobic digestion technology can greatly affect the amount of energy crops. Benefit of waste is governed primarily by such projects, where is the problem of ensuring sufficient energy crops. The proposed composition of raw materials also allows the implementation of the existing ope­ra­tion of anaerobic digestion. Operational data on real operations demonstrate the real possibility of further development of the area and secondly the use of biogas plants as well as in the preparation of suitably prepared substrates for the operators. The entire data set underwent a complete statistical analysis. Differences between variants were statistically significant.

  1. Enhanced biomethanation of kitchen waste by different pre-treatments.

    Science.gov (United States)

    Ma, Jingxing; Duong, Thu Hang; Smits, Marianne; Verstraete, Willy; Carballa, Marta

    2011-01-01

    Five different pre-treatments were investigated to enhance the solubilisation and anaerobic biodegradability of kitchen waste (KW) in thermophilic batch and continuous tests. In the batch solubilisation tests, the highest and the lowest solubilisation efficiency were achieved with the thermo-acid and the pressure-depressure pre-treatments, respectively. However, in the batch biodegradability tests, the highest cumulative biogas production was obtained with the pressure-depressure method. In the continuous tests, the best performance in terms of an acceptable biogas production efficiency of 60% and stable in-reactor CODs and VFA concentrations corresponded to the pressure-depressure reactor, followed by freeze-thaw, acid, thermo-acid, thermo and control. The maximum OLR (5 g COD L(-1) d(-1)) applied in the pressure-depressure and freeze-thaw reactors almost doubled the control reactor. From the overall analysis, the freeze-thaw pre-treatment was the most profitable process with a net potential profit of around 11.5 € ton(-1) KW.

  2. Anaerobic Codigestion of Sludge: Addition of Butcher’s Fat Waste as a Cosubstrate for Increasing Biogas Production

    Science.gov (United States)

    Martínez, E. J.; Gil, M. V.; Fernandez, C.; Rosas, J. G.

    2016-01-01

    Fat waste discarded from butcheries was used as a cosubstrate in the anaerobic codigestion of sewage sludge (SS). The process was evaluated under mesophilic and thermophilic conditions. The codigestion was successfully attained despite some inhibitory stages initially present that had their origin in the accumulation of volatile fatty acids (VFA) and adsorption of long-chain fatty acids (LCFA). The addition of a fat waste improved digestion stability and increased biogas yields thanks to the higher organic loading rate (OLR) applied to the reactors. However, thermophilic digestion was characterized by an effluent of poor quality and high VFA content. Results from spectroscopic analysis suggested the adsorption of lipid components onto the anaerobic biomass, thus disturbing the complete degradation of substrate during the treatment. The formation of fatty aggregates in the thermophilic reactor prevented process failure by avoiding the exposure of biomass to the toxic effect of high LCFA concentrations. PMID:27071074

  3. A comparison of microbial characteristics between the thermophilic and mesophilic anaerobic digesters exposed to elevated food waste loadings.

    Science.gov (United States)

    Guo, Xiaohui; Wang, Cheng; Sun, Faqian; Zhu, Weijing; Wu, Weixiang

    2014-01-01

    Thermophilic and mesophilic anaerobic digestion reactors (TR and MR) using food waste as substrate were compared with emphasis on microbial responses to increasing organic loading rate (OLR). At OLR ranging from 1.0 to 2.5 g VS L(-1) d(-1), MR exhibited more stable performance compared to TR in terms of methane yield. Amplicons pyrosequencing results revealed the distinct microbial dynamics in the two reactors. Primarily, MR had greater richness and evenness of bacteria species. With OLR elevated, larger shifts of bacterial phylogeny were observed in MR; Methanosaeta dominated in archaeal community in MR while Methanothermobacter and Methanoculleus were favored in TR. The high functional redundancy in bacterial community integrated with acetoclastic methanogenesis in MR resulted in its better performance; whereas delicate interactions between hydrogen-producer and hydrogenotrophic methanogens in TR were much more prone to disruption. These results are conductive to understanding the microbial mechanisms of low methane yield during food waste anaerobic digestion.

  4. Application of the IWA ADM1 model to simulate anaerobic co-digestion of organic waste with waste activated sludge in mesophilic condition.

    Science.gov (United States)

    Derbal, K; Bencheikh-Lehocine, M; Cecchi, F; Meniai, A-H; Pavan, P

    2009-02-01

    Anaerobic digestion model no. 1 model of international water association was applied to a full scale anaerobic co-digestion process for the treatment of the organic fraction of municipal solid wastes along with activated sludge wastes originating from a municipal wastewater treatment plant. This operation was carried out in a digester of 2000 m(3) in volume. It is operates at an average hydraulic retention time of 26.9 days with an average organic loading rate of 1.01 kg TVS/m(3) day, at a temperature of 37 degrees C with an average gas production rate of 0.296 m(3)/m(3) day. The aim of the present study is to compare the results obtained from the simulation with the experimental values. The simulated results showed a good fit for pH, methane and carbon dioxide percentages, biogas volume, chemical oxygen demand, total volatile fatty acids, inorganic nitrogen and inorganic carbon.

  5. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Hoyos-Hernandez, Carolina; Hoffmann, Marieke; Guenne, Angeline; Mazeas, Laurent

    2014-02-01

    Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55°C was followed using an isotopic tracing approach ((13)C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate. Benzoate is known to be a phenol metabolite under mesophilic conditions, but in this study it was found for the first time to be a phenol degradation product at thermophilic temperature.

  6. Characterization of food market wastes as substrate for anaerobic digestion; Caracterizacao do lixo de CEASA como substrato para biodigestao anaerobia

    Energy Technology Data Exchange (ETDEWEB)

    Benincasa, Maria [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas; Lucas Junior, Jorge de [UNESP, Jaboticabal, SP (Brazil). Faculdade de Ciencias Agrarias e Veterinarias

    2000-03-01

    This research was carried out in order to study organic wastes from food markets as a substrate for anaerobic digestion. The experiment was conducted at the Department of Rural Engineering - Campus of Jaboticabal/UNESP, S P, Brazil. Biogas production data indicated the garbage potential, the fermentation time and the solids reduction for fresh garbage and dry and milled garbage. The biogas yield was 0,422 m{sup 3}/kg V S added. (author)

  7. Importance of food waste pre-treatment efficiency for global warming potential in life cycle assessment of anaerobic digestion systems

    DEFF Research Database (Denmark)

    Carlsson, My; Naroznova, Irina; Møller, Jacob

    2015-01-01

    A need for improvement of food waste (FIAT) pre-treatment methods has been recognized, but few life cycle assessments (LCA) of FIN management systems have considered the pre-treatment with respect to input energy, loss of organic material and nutrients for anaerobic digestion (AD) and/or further...... treatment of the refuse. The objective of this study was to investigate how FW pre-treatment efficiency impacts the environmental performance of waste management, with respect to global warming potential (GWP). The modeling tool EASETECH was used to perform consequential LCA focusing on the impact...

  8. Energetic autonomy of waste water treatment plants using anaerobic co-digestion of sewage sludges and MSW - A case study

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F.; Traverso, P.G.; Chiesa, G.; Bozzola, L.

    The paper is a technical and economic analysis of the possibility to apply the sorted organic fraction of municipal solid wastes (MSW) to the anaerobic stabilization section of sewage sludge in a waste water treatment plant. The aim is to attain energetic autonomy of the plant through the increasing of the gas production rate. The study shows that savings of 65,000,000 Italian lire per year can be obtained with an investment cost of 300,000,000 lire. At the current interest rate (4-10%), this total amount can be paid back within 4 to 6 years.

  9. Anaerobic co-digestion of commercial food waste and dairy manure: Characterizing biochemical parameters and synergistic effects.

    Science.gov (United States)

    Ebner, Jacqueline H; Labatut, Rodrigo A; Lodge, Jeffrey S; Williamson, Anahita A; Trabold, Thomas A

    2016-06-01

    Anaerobic digestion of commercial food waste is a promising alternative to landfilling commercial food waste. This study characterized 11 types of commercial food wastes and 12 co-digestion blends. Bio-methane potential, biodegradable fraction, and apparent first-order hydrolysis rate coefficients were reported based upon biochemical methane potential (BMP) assays. Food waste bio-methane potentials ranged from 165 to 496 mL CH4/g VS. Substrates high in lipids or readily degradable carbohydrates showed the highest methane production. Average bio-methane potential observed for co-digested substrates was -5% to +20% that of the bio-methane potential of the individual substrates weighted by VS content. Apparent hydrolysis rate coefficients ranged from 0.19d(-1) to 0.65d(-1). Co-digested substrates showed an accelerated apparent hydrolysis rate relative to the weighted average of individual substrate rates. These results provide a database of key bio-digestion parameters to advance modeling and utilization of commercial food waste in anaerobic digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Biogas production from brewery spent grain enhanced by bioaugmentation with hydrolytic anaerobic bacteria.

    Science.gov (United States)

    Čater, Maša; Fanedl, Lijana; Malovrh, Špela; Logar, Romana Marinšek

    2015-06-01

    Lignocellulosic substrates are widely available but not easily applied in biogas production due to their poor anaerobic degradation. The effect of bioaugmentation by anaerobic hydrolytic bacteria on biogas production was determined by the biochemical methane potential assay. Microbial biomass from full scale upflow anaerobic sludge blanket reactor treating brewery wastewater was a source of active microorganisms and brewery spent grain a model lignocellulosic substrate. Ruminococcus flavefaciens 007C, Pseudobutyrivibrio xylanivorans Mz5(T), Fibrobacter succinogenes S85 and Clostridium cellulovorans as pure and mixed cultures were used to enhance the lignocellulose degradation and elevate the biogas production. P. xylanivorans Mz5(T) was the most successful in elevating methane production (+17.8%), followed by the coculture of P. xylanivorans Mz5(T) and F. succinogenes S85 (+6.9%) and the coculture of C. cellulovorans and F. succinogenes S85 (+4.9%). Changes in microbial community structure were detected by fingerprinting techniques.

  11. Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste.

    Science.gov (United States)

    Sajeena Beevi, B; Madhu, G; Sahoo, Deepak Kumar

    2015-02-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration of 100g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9L/kg VS (volatile solid) for the total solid (TS) concentration of 100g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day(-1).

  12. Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Sajeena Beevi, B., E-mail: sajeenanazer@gmail.com [Department of Chemical Engineering, Govt. Engineering College, Thrissur, Kerala 680 009 (India); Madhu, G., E-mail: profmadhugopal@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India); Sahoo, Deepak Kumar, E-mail: dksahoo@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India)

    2015-02-15

    Highlights: • Performance of the reactor was evaluated by the degradation of volatile solids. • Biogas yield at the end of the digestion was 52.9 L/kg VS. • Value of reaction rate constant, k, obtained was 0.0249 day{sup −1}. • During the digestion 66.7% of the volatile solid degradation was obtained. - Abstract: Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration of 100 g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS (volatile solid) for the total solid (TS) concentration of 100 g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day{sup −1}.

  13. The role of different methanogen groups evaluated by Real-Time qPCR as high-efficiency bioindicators of wet anaerobic co-digestion of organic waste

    Science.gov (United States)

    2011-01-01

    Methanogen populations and their domains are poorly understood; however, in recent years, research on this topic has emerged. The relevance of this field has also been enhanced by the growing economic interest in methanogen skills, particularly the production of methane from organic substrates. Management attention turned to anaerobic wastes digestion because the volume and environmental impact reductions. Methanogenesis is the biochemically limiting step of the process and the industrially interesting phase because it connects to the amount of biogas production. For this reason, several studies have evaluated the structure of methanogen communities during this process. Currently, it is clear that the methanogen load and diversity depend on the feeding characteristics and the process conditions, but not much data is available. In this study, we apply a Real-Time Polymerase Chain Reaction (RT-PCR) method based on mcrA target to evaluate, by specific probes, some subgroups of methanogens during the mesophilic anaerobic digestion process fed wastewater sludge and organic fraction of the municipal solid waste with two different pre-treatments. The obtained data showed the prevalence of Methanomicrobiales and significantly positive correlation between Methanosarcina and Methanosaetae and the biogas production rate (0.744 p < 0.01 and 0.641 p < 0.05). Methanosarcina detected levels are different during the process after the two pre-treatment of the input materials (T-test p < 0.05). Moreover, a role as diagnostic tool could be suggested in digestion optimisation. PMID:21982396

  14. Advanced anaerobic bioconversion of lignocellulosic waste for the melissa life support system

    Science.gov (United States)

    Lissens, G.; Verstraete, W.; Albrecht, T.; Brunner, G.; Creuly, C.; Dussap, G.; Kube, J.; Maerkl, H.; Lasseur, C.

    The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of the MELiSSA loop (Micro-Ecological Life Support System Alternative). The treatment comprised a series of processes, i.e. a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor, a fiber liquefaction reactor employing the rumen bacterium Fibrobacter succinogenes and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g-1 VSS (volatile suspended solids) added at a RT (hydraulic retention time) of 20-25 d was obtained. Biogas yields could not be increased considerably at higher RT, indicating the depletion of readily available substrate after 25 d. The solids present in the CSTR-effluent were subsequently treated in two ways. Hydrothermal treatment (T ˜ 310-350C, p ˜ 240 bar) resulted in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete sanitation of the residue. Application of the cellulolytic Fibrobacter succinogenes converted remaining cellulose contained in the CSTR-effluent into acetate and propionate mainly. Subsequent anaerobic digestion of the hydrothermolysis and the Fibrobacter hydrolysates allowed conversion of 48-60% and 30%, respectively. Thus, the total process yielded biogas corresponding with conversions up to 90% of the original organic matter. It appears that particularly mesophilic digestion in conjunction with hydrothermolysis offers interesting features for (nearly) the MELiSSA system. The described additional technologies show that complete and hygienic carbon and energy recovery from human waste within MELiSSA is technically feasible, provided that the extra energy needed for the thermal treatment is guaranteed.

  15. Effects of multiple inhibitory components on anaerobic treatment processes in municipal solid waste incineration leachate.

    Science.gov (United States)

    Lei, Yuqing; Dang, Yan; Lan, Zhangheng; Sun, Dezhi

    2016-06-01

    This study served to investigate the comparative and combined effects of calcium, ammonia nitrogen, and aquatic humic substances (AHS) on specific methanogenic activity (SMA) in municipal solid waste leachate at mesophilic conditions. Using orthogonal experiments, anaerobic granular sludge was cultured with different concentrations combinations of the three added components for 13 days. The combination of 6000 mg/L calcium, 400 mg/L ammonia nitrogen, and 4000 mg/L AHS was the most inhibitory combination on the SMA of granular sludge, with a calculated 4.49 mL (standard temperature and atmospheric pressure) (STP) CH4/(gVSS·d) of SMA. The SMA with the addition of the inhibitory components was much lower than the control group's (1000 mg/L calcium, 200 mg/L ammonia nitrogen and 2000 mg/L AHS) with a calculated 12.97 mL (STP) CH4/(gVSS·d) of SMA. Calcium was the major inhibitor among the three components followed by AHS. High concentrations of calcium significantly inhibited the utilization of propionate and butyrate in the substrate and further affected the methanogenic process.

  16. Ammonia removal in food waste anaerobic digestion using a side-stream stripping process.

    Science.gov (United States)

    Serna-Maza, A; Heaven, S; Banks, C J

    2014-01-01

    Three 35-L anaerobic digesters fed on source segregated food waste were coupled to side-stream ammonia stripping columns and operated semi-continuously over 300 days, with results in terms of performance and stability compared to those of a control digester without stripping. Biogas was used as the stripping medium, and the columns were operated under different conditions of temperature (55, 70, 85 °C), pH (unadjusted and pH 10), and RT (2-5 days). To reduce digester TAN concentrations to a useful level a high temperature (≥70 °C) and a pH of 10 were needed; under these conditions 48% of the TAN was removed over a 138-day period without any detrimental effects on digester performance. Other effects of the stripping process were an overall reduction in digestate organic nitrogen-containing fraction compared to the control and a recovery in the acetoclastic pathway when TAN concentration was 1770±20 mg kg(-1).

  17. Effects of organic composition on mesophilic anaerobic digestion of food waste.

    Science.gov (United States)

    Li, Yangyang; Jin, Yiying; Borrion, Aiduan; Li, Hailong; Li, Jinhui

    2017-11-01

    Anaerobic digestion of food waste (FW) has been widely investigated, however, little is known about the influence of organic composition on the FW digestion process. This study aims to identify the optimum composition ratios of carbohydrate (CA), protein (CP) and lipid (EE) for maintaining high methane yield and process stability. The results show that the CA-CP-EE ratio was significantly correlated with performance and degradability parameters. Controlling the CA-CP-EE ratio higher than 1.89 (CA higher than 8.3%, CP lower than 5.0%, and EE lower than 5.6%) could be an effective way to maintain stable digestion and achieve higher methane production (385-627mL/gVS) and shorter digestion retention (196-409h). The CA-CP-EE ratio could be used as an important indicator for digestion performance. To effectively evaluate organic reduction, the concentration and removal efficiency of organic compositions in both solid phases and total FW should be considered. Copyright © 2017. Published by Elsevier Ltd.

  18. Treatment of leachate from the anaerobic fermentation of solid wastes using two biofilm support media.

    Science.gov (United States)

    Comett, I; González-Martinez, S; Wilderer, P

    2004-01-01

    Biofilms growing on different carrier media have a different response to the nutrients contained in wastewater. Biofilms have proven to be an alternative to the treatment of wastewater containing higher concentrations of contaminants. The main objective of this research was to compare two biofilm support media for the treatment of leachate from the anaerobic fermentation of solid wastes. The removal of organic matter and ammonia was achieved in two fixed bed biofilm reactors containing Kaldnes and Linpor support materials with specific surface areas of 490 and 270 m2/m3, respectively, and operating under the sequencing batch procedure during 204 days. The Linpor reactor achieved higher total COD removal than the Kaldnes reactor (47% and 39%, respectively). Linpor was shown to be less sensitive to influent COD changes than Kaldnes. The effluent total COD values of Kaldnes were higher than Linpor. The dissolved COD removal was 21% for both reactors. The average ammonia removal for Linpor was 72% and 42% for Kaldnes. The matrix of Linpor allows higher concentrations of microorganisms (as dry mass) than Kaldnes. The dry mass concentration was related to the "active" exposed surface area of the biofilm. This is considered to be the cause for the better performance of Linpor when compared with Kaldnes.

  19. Solid-state anaerobic co-digestion of hay and soybean processing waste for biogas production.

    Science.gov (United States)

    Zhu, Jiying; Zheng, Yi; Xu, Fuqing; Li, Yebo

    2014-02-01

    Co-digestion of soybean processing waste (SPW) and hay in solid-state anaerobic digestion (SS-AD) for biogas production was investigated. Effects of the SPW to hay ratio, feedstock to effluent (inoculum) ratio, premixing of effluent with feedstock, and leachate recirculation on biogas production via SS-AD were studied. The highest methane yield of 258 L/kg VS was obtained with a SPW/hay ratio of 75:25 and feedstock/effluent (F/E) ratio of 3, which was 148% and 50% higher than that of 100% SPW and 100% hay, respectively. Increasing the F/E ratio from 1 to 5 decreased methane yield, however the highest volumetric methane yield (16.2L/L reactor) was obtained at an F/E of 3. There was no significant difference in methane yields between premixing 50% and 100% of the effluent. Leachate recirculation significantly accelerated the SS-AD start-up process when effluent was not completely premixed.

  20. Bio-Hydrogen Production from Pineapple Waste Extract by Anaerobic Mixed Cultures

    Directory of Open Access Journals (Sweden)

    Chakkrit Sreela-or

    2013-04-01

    Full Text Available A statistical experimental design was employed to optimize factors that affect the production of hydrogen from the glucose contained in pineapple waste extract by anaerobic mixed cultures. Results from Plackett-Burman design indicated that substrate concentration, initial pH and FeSO4 concentration had a statistically significant (p ≤ 0.05 influence on the hydrogen production potential (Ps and the specific hydrogen production rate (SHPR. The path of steepest ascent was undertaken to approach the optimal region of these three significant factors which was then optimized using response surface methodology (RSM with central composite design (CCD. The presence of a substrate concentration of 25.76 g-total sugar/L, initial pH of 5.56, and FeSO4 concentration of 0.81 g/L gave a maximum predicted Ps of 5489 mL H2/L, hydrogen yield of 1.83 mol H2/mol glucose, and SHPR of 77.31 mL H2/g-volatile suspended solid (VSS h. A verification experiment indicated highly reproducible results with the observed Ps and SHPR being only 1.13% and 1.14% different from the predicted values.

  1. Two stage anaerobic baffled reactors for bio-hydrogen production from municipal food waste.

    Science.gov (United States)

    Tawfik, A; Salem, A; El-Qelish, M

    2011-09-01

    A two-step anaerobic baffled reactor (ABR-1 and ABR-2) for H2 production from municipal food waste (MFW) was investigated at a temperature of 26 °C. In ABR-1, the average yield of H2 at an HRT of 26 h and OLR of 58 kg COD/m3 d was 250 ml H2/g VS removed. As unexpected; the H2 production in the ABR-2 was further increased up to 370 ml H2/gVS removed at a HRT of 26 h and OLR of 35 kg COD/m3 d. The total H2 yield in the two-step process was estimated to be 4.9 mol H2/mol hexose. The major part of H2 production in the ABR-1 was due to the conversion of COD(particulate) (36%). In the ABR-2 the H2 yield was mainly due to the conversion of COD in the soluble form (76%). Based on these results MFW could be ideal substrate for H2 production in a two-step ABR processes.

  2. Biogas Production through the Anaerobic Digestion of Date Palm Tree Wastes - Process Optimization

    Directory of Open Access Journals (Sweden)

    Fahad Y. Al-Juhaimi

    2014-04-01

    Full Text Available A process for the production of biogas through the anaerobic digestion (AD of date palm tree waste (DPTW was developed. The effects of different substrate pretreatments and operating conditions on the yield of biogas and on the chemical composition of DPTW before and after AD were studied. The best results were obtained using alkali pretreatment, with a particle size of 2 to 5 mm, a C:N ratio of 30:1, a digestion temperature of 40 °C, an initial pH of 7.0, and a volatile solids concentration of approximately 10%. The production of flammable biogas containing up to 50% methane started after about one week of operation and continued for approximately 11 weeks. The highest average biogas yield obtained was 342.2 L gas/kg of volatile solids fed to the digester. The highest maximum and average volumetric biogas production rates obtained were 674.5 and 404.4 L/m3 of digester volume per day, respectively. After digestion, there was up to a 58% reduction in the organic matter content of the substrate. Reductions in the contents of cellulose, hemicellulose, and soluble organic compounds were 68.7, 73.4, and 71.9%, respectively, while the ash and lignin contents remained mostly constant. The remaining sludge contained nutrient minerals and some organic matter which qualifies it as a potential soil fertilizer for crop production.

  3. Zero Valent Iron Significantly Enhances Methane Production from Waste Activated Sludge by Improving Biochemical Methane Potential Rather Than Hydrolysis Rate

    Science.gov (United States)

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-01

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system.

  4. Zero valent iron significantly enhances methane production from waste activated sludge by improving biochemical methane potential rather than hydrolysis rate.

    Science.gov (United States)

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-05

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system.

  5. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide.

    Science.gov (United States)

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J

    2012-01-01

    In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H(2)O(2)) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175°C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115°C and 145°C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175°C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for SWA20 at 145°C, with a 26% increase in biogas production after 8days of digestion, compared to the control. When considering the increased substrate availability in the liquid fraction after MW pretreatment, a 78% improvement in biogas production vs. the control was achieved. Combining MW and H(2)O(2) modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. In general, all samples pretreated with H(2)O(2) displayed a long lag phase and the CBP was usually lower than MW irradiated only samples. First order rate constant was calculated.

  6. Performances of Two-phase CSTR-ASBR with Enhanced Hydrolysis and Acidification for Anaerobic Digestion of Fruit and Vegetable Wastes%果蔬废物CSTR-ASBR强化酸化分相厌氧消化产气性能研究

    Institute of Scientific and Technical Information of China (English)

    蔡文婷; 朱保宁; 李兵; 袁海荣; 邹德勋; 李秀金

    2012-01-01

    采用CSTR-ASBR强化酸化分相工艺对果蔬废物厌氧消化产气性能进行研究.通过先将果蔬废物榨汁,果蔬渣水解酸化后再进入到甲烷相,果蔬汁直接进行甲烷化的方式,实现强化酸化与分相厌氧消化.结果表明:采用此种厌氧消化方式,可以使酸化相稳定运行的最高负荷达到16 gVS·L-1d-1,将酸化相的末端产物均换算成乙酸后,负荷产酸率平均在800 mg·gVS-1d-1以上,并形成稳定的乙醇发酵类型.甲烷相的有机负荷可从1 gVS·L-1d-1上升到5.5 gVS·L-1d-1,负荷产气率平均在500 mL·gVS-1 d-以上,CH4含量稳定在55%~60%之间.甲烷相运行的最优负荷为4 gVS·L-1d-1,负荷产气率与VS去除率分别可达557 mL·gVS-1d-1和83%,且系统稳定性能良好.%Two-phase CSTR-ASBR system with enhanced hydrolysis and acidification was advanced and used for anaerobic digestion of fruit and vegetable wastes( FVW) for biogas production. The performance of the system was investigated. FVW was firstly separated by extrusion. The solid fraction was hydrolyzed and acidified in acidogenic phase and then added into methanogenic phase and co-digested with liquid fraction. The results showed that the acidogenic phase reached maximum OLR of 16 gVS ? L-1d-1, the VFA yield was 800 mg CH3COOH ? gVS-1d-1, and the phase maintained a stable ethanol type fermentation. The methanogenic phase reached maximum OLR of 5. 5 gVS ? L-1 d-1 with biogas yield of 500 mL ? gyS-1d on average. Methane content in biogas was in range of 55% ~ 60%. At the optimum OLR of methanogenic phase (4 gVS ? L-1d-1 ) , the biogas yield and the VS removal rate were 557 mL ? gVS-1d-1 and 83% .respectively. The system was operated in stable state.

  7. Utilization of biogas produced by anaerobic digestion of agro-industrial waste: Energy, economic and environmental effects.

    Science.gov (United States)

    Hublin, Andrea; Schneider, Daniel Rolph; Džodan, Janko

    2014-07-01

    Anaerobic digestion of agro-industrial waste is of significant interest in order to facilitate a sustainable development of energy supply. Using of material and energy potentials of agro-industrial waste, in the framework of technical, economic, and ecological possibilities, contributes in increasing the share of energy generated from renewable energy sources. The paper deals with the benefits arising from the utilization of biogas produced by co-digestion of whey and cow manure. The advantages of this process are the profitability of the plant and the convenience in realizing an anaerobic digestion plant to produce biogas that is enabled by the benefits from the sale of electric energy at favorable prices. Economic aspects are related to the capital cost (€ 2,250,000) of anaerobic digestion treatment in a biogas plant with a 300 kW power and 510 kW heating unit in a medium size farm (450 livestock units). Considering the optimum biogas yield of 20.7 dm(3) kg(-1) of wet substrate and methane content in the biogas obtained of 79%, the anaerobic process results in a daily methane production of 2,500 kg, with the maximum power generation of 2,160,000 kWh y(-1) and heat generation of 2,400,000 kWh y(-1) The net present value (NPV), internal rate of return (IRR) and payback period for implementation of profitable anaerobic digestion process is evaluated. Ecological aspects related to carbon dioxide (CO2) and methane (CH4) emission reduction are assessed.

  8. BIOGAS PROCTION FROM ANAEROBIC CO-DIGESTION OF COW DUNG AND ORGANIC WASTES (NAPIER PAK CHONG I AND FOOD WASTE IN THAILAND: TEMPERATURE EFFECT ON BIOGAS PRODUCT

    Directory of Open Access Journals (Sweden)

    Lertluck Saitawee

    2014-01-01

    Full Text Available Biogas production has been attracting increasing attention as a biofuel of the future because biogas technology not only constitutes a biofuel source, but also can be applied in the various environmental pollutants. Anaerobic digestion of high solid slurries (such as food waste and cow dung is typically performed in continuously reactor (by force substrate flow to avoid problems with a thick floating layer or large amounts of sediments. Temperature also seems to have profound influence on the biogas production. The objective of the study was to identify the optimum biogas production for anaerobic co-digestion of cow dung and organic wastes (napierpakchong I and food waste. Influence of temperature (psyhrophilic temperature 25°C and thermoplilic temperature 45°C and active biogas process on single substrate (food waste feed and co-digestion of cow dung and organic wastes (napierpakchong I and food waste was used, within the reactor was studies in 1.80 cm high over a 45 day. Results showed that best digestion was achieved when digested of cow dung, napierpakchong I and food waste on 1:1:1 and thermoplilic temperature. Maximum biogas production (R4, biogas yield, methane content and %VS reduction was found that 70 L/day, 70 L/VS feed, 65 and 80%, respectively. The result showed that the biogas production increased progressively withhigher temperature.The increased in biogas production in thermophilic temperature and psyhrophilic temperature could be up 28.01 and 26%, respectively. The biogas yield increased 12.5% of co-digestion system, which compared to thermophilic temperature and psyhrophilic temperature (R4 and R2. This behavior might be due to the higher degradability. Therefore, temperature of digester can be used effectively as an operating strategy to optimize biogas production.

  9. Energy- and CO2-reduction potentials by anaerobic treatment of wastewater and organic kitchen wastes in consideration of different climatic conditions.

    Science.gov (United States)

    Weichgrebe, D; Urban, I; Friedrich, K

    2008-01-01

    The classical municipal wastewater treatment in Germany consists of an aerobic carbon and nitrogen elimination and mostly an anaerobic sludge treatment. Organic kitchen wastes from separate waste collection as well as yard wastes are converted mostly in composting plants to soil conditioner. With these conventional types of treatment, the energy potential in waste and wastewater is lost due to aerobic material conversion. In this article three scenarios for the treatment of municipal wastewater and waste are compared on the subject of energy efficiency and useable potential: Sc1. the classical wastewater treatment and the composting of the organic waste fraction, Sc2. the anaerobic treatment of wastewater combined with deammonification and the digestion of the organic waste fraction, and Sc3. a mutual anaerobic treatment of wastewater and waste as co-digestion with deammonification. The calculation of energy and CO2-balance considers different climatic conditions. In case of using anaerobic treatment, not only the energy balance will be positive, also the CO2-balance is improved by the substitution of fossil fuels with generated biogas.

  10. Modeling the effect of heat fluxes on ammonia and nitrous oxide emissions from an anaerobic swine waste treatment lagoon using artificial neural network

    Science.gov (United States)

    Understanding factors that affect ammonia and nitrous emissions from anaerobic swine waste treatment lagoons or any animal waste receptacles is a necessary first step in deploying potential remediation options. In this study, we examined the various meteorological factors (i.e., air temperatures, s...

  11. Effects of Metal Nanoparticles on Methane Production from Waste-Activated Sludge and Microorganism Community Shift in Anaerobic Granular Sludge

    Science.gov (United States)

    Wang, Tao; Zhang, Dong; Dai, Lingling; Chen, Yinguang; Dai, Xiaohu

    2016-05-01

    Extensive use of nanoparticles (NPs) in consumer and industrial products has led to concerns about their potential environmental impacts; however, the influences of different NPs (e.g., nZVI (nano zero-valent iron), Ag NPs, Fe2O3 NPs and MgO NPs) on the anaerobic digestion of sludge have not yet been studied in depth. Additionally, a new guideline or the use of different NPs in the anaerobic digestion of sludge should be established to improve the anaerobic digestion of sludge and avoid inhibitory effects. This study investigated the effects of four representative NPs (i.e., nZVI, Ag NPs, Fe2O3 NPs and MgO NPs) on methane production during the anaerobic digestion of waste activated sludge (WAS). The presence of 10 mg/g total suspended solids (TSS) nZVI and 100 mg/g TSS Fe2O3 NPs increased methane production to 120% and 117% of the control, respectively, whereas 500 mg/g TSS Ag NPs and 500 mg/g TSS MgO NPs generated lower levels of methane production (73.52% and 1.08% that of the control, respectively). These results showed that low concentrations of nZVI and Fe2O3 NPs promoted the amount of microbes (Bacteria and Archaea) and activities of key enzymes but that higher concentrations of Ag NPs and MgO NPs inhibited them.

  12. Co-digestion of tobacco waste with different agricultural biomass feedstocks and the inhibition of tobacco viruses by anaerobic digestion.

    Science.gov (United States)

    Liu, Yi; Dong, Jianxin; Liu, Gangjin; Yang, Hongnan; Liu, Wei; Wang, Lan; Kong, Chuixue; Zheng, Dan; Yang, Jinguang; Deng, Liangwei; Wang, Shusheng

    2015-01-01

    Tobacco is widely planted across the world especially in China, which means that a large amount of tobacco waste needs to be treated. This study investigated the biogas fermentation of tobacco stalks co-digested with different biomass feedstocks and the inactivation of Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV) by anaerobic digestion. Results showed that the maximum methane yield of tobacco stalks at 35 °C was 0.163 m(3) CH4 ⋅ kg VS(-1), which was from the co-digestion of tobacco stalks, wheat stalks and pig manure. The largest VS removal rate of tobacco stalks was 59.10%. Proven by indicator paper stripe, half-leaf lesion and RT-PCR, CMV could be inactivated by mesophilic and thermophilic anaerobic digestion, whereas TMV could be only inactivated by thermophilic anaerobic digestion over 20 days. These results suggested that using tobacco stalks as feedstock for anaerobic digestion and applying the digested residue and slurry to Solanaceae crop land are feasible.

  13. 6th Conference 'Anaerobic treatment of biological wastes'. New tendencies in the biogas technology; 6. Fachtagung Anaerobe biologische Abfallbehandlung. Neue Tendenzen in der Biogastechnologie

    Energy Technology Data Exchange (ETDEWEB)

    Bilitewski, B.; Werner, P.; Dornack, Christina; Stegmann, R.; Rettenberger, G.; Faulstich, M.; Wittmaier, M. (eds.)

    2008-07-01

    Within this 6th conference at 23rd to 24th September, 2008, in Dresden (Federal Republic of Germany), the following lectures were held: (1) Development of biogas technology - influences and tendencies (H. Friedmann); (2) EEG 2009 - Effect on biogas branch (B. Dreher); (3) From composting to fermentation - material flows, technology, cost, practical experiences (M. Kern, T. Raussen, A. Lootsma, K. Funda); (4) Fermentation of vinasses from the production of bioethanol (H. Friedmann); (5) Substrate digestion and microbiological hydrolysis for biogas production from lignocellulosis containing substrates using beer draff as an example (D. Schieder, M. Faulstich, J. Voigt, J. Ellenriedere, B. Haeffner, K. Sommer); (6) Substitution of wheat and corn by grass and manure for improving the economic efficiency of biogas plants (M. Wittmaier); (7) High-efficiency anaerobic digestion with integrated micro filtration using clarification sludge as an example (W. Troesch, B. Kempter-Regel); (8) Modelling of anaerobic digestion; stationary and dynamic parameter of estimation (C. Cimatoribus); (9) Regulation of an anaerobic laboratory reactor by means of fuzzy logic (O. Bade); (10) Model based diagnosis of the state of process in biogas plants (W. Kloeden); (11) Suitability of ADM 1 in the modelling of biogas plants (K. Koch, M. Wichern, M. Luebken, H. Horn, M. Schlattmann, A. Gronauer); (12) Load dependent and automatical operation of biogas plants - an option for the future (M. Mueller, J. Proeter, F. Scholwin); (13) Chances for biogas generation and application in Vietnam (L. van Bot, M. Wittmaier, A. Karagiannidies, B. Bilitewski, P. Werner); (14) State of the art and developments in the fermentation of biological wastes in the Peoples Republic of China (M. Gehring, R. Li, B. Raininger); (15) Bio-methane potential from cattle and pig wastes in Greece (A. Karagiannidis, G. Perkoulidis, T. Kotsopoulos); (16) Contaminants in biogas plants - an assessment of the material flow using

  14. Biogas Production from Distilled Grain Waste by Thermophilic Dry Anaerobic Digestion: Pretreatment of Feedstock and Dynamics of Microbial Community.

    Science.gov (United States)

    Wang, Ting-Ting; Sun, Zhao-Yong; Huang, Yu-Lian; Tan, Li; Tang, Yue-Qin; Kida, Kenji

    2017-08-24

    Distilled grain waste (DGW) eluted from the Chinese liquor making process poses potential serious environmental problems. The objective of this study is to evaluate the feasibility of converting DGW to biogas by thermophilic dry anaerobic digestion. To improve biogas production, the effects of dilute H2SO4 and thermal pretreatment on DGW were evaluated by biochemical methane potential (BMP) tests. The results indicate that 90 °C thermal pretreatment provided the highest methane production at 212.7 mL/g-VTSadd. The long-term thermophilic dry anaerobic digestion process was conducted in a 5-L separable flask for more than 3 years at a volatile total solid (VTS) loading rate of 1 g/kg-sludge/d, using synthetic waste, untreated and 90 °C thermal pretreated DGW as the feedstock, respectively. A higher methane production, 451.6 mL/g-VTSadd, was obtained when synthetic waste was used; the methane production decreased to 139.4 mL/g-VTSadd when the untreated DGW was used. The 90 °C thermal pretreated DGW increased the methane production to 190.5 mL/g-VTSadd, showing an increase of 36.7% in methane production compared with that using untreated DGW. The microbial community structure analysis indicates that the microbial community in the thermophilic dry anaerobic digestion system maintained a similar structure when untreated or pretreated DGW was used, whereas the structure differed significantly when synthetic waste was used as the feedstock.

  15. DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; M. Folmsbee; D. Nagle

    2004-05-31

    Our work focuses on the use of microorganisms to recover petroleum hydrocarbons that remain entrapped after current recovery technologies reach their economic limit. Capillary forces between the hydrocarbon and aqueous phases are largely responsible for trapping the hydrocarbons in the pores of the rock and large reductions in the interfacial tension between the hydrocarbon and aqueous phases are needed for hydrocarbon mobilization (1-3, 10, 11). Microorganisms produce a variety of biosurfactants (4), several of which generate the ultra low interfacial tensions needed for hydrocarbon mobilization (4, 5, 8). In particular, the lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 reduces the interfacial tension between hydrocarbon and aqueous phases to very low levels (<0.016 mN/m) (8) (9). B. mojavensis JF-2 grows under the environmental conditions found in many oil reservoirs, i. e., anaerobic, NaCl concentrations up to 80 g l{sup -1}, and temperatures up to 45 C (6, 7), making it ideally suited for in situ applications. However, anaerobic growth of B. mojavensis JF-2 was inconsistent and difficult to replicate, which limited its use for in situ applications. Our initial studies revealed that enzymatic digests, such as Proteose Peptone, were required for anaerobic growth of Bacillus mojavensis JF-2. Subsequent purification of the growth-enhancing factor in Proteose Peptone resulted in the identification of the growth-enhancing factor as DNA or deoxyribonucleosides. The addition of salmon sperm DNA, herring sperm DNA, E. coli DNA or synthetic DNA (single or double stranded) to Medium E all supported anaerobic growth of JF-2. Further, we found that JF-2 required all four deoxyribonucleosides (deoxyadeonosine, deoxyguanosine, deoxycytidine and thymidine) for growth under strict anaerobic conditions. The requirement for the deoxyribonucleosides did not occur under aerobic growth conditions. DNA was not used as a sole energy source; sucrose was required

  16. Experiences with anaerobic treatment of fat-containing food waste liquids: two full scale studies with a novel anaerobic flotation reactor.

    Science.gov (United States)

    Frijters, C T M J; Jorna, T; Hesselink, G; Kruit, J; van Schaick, D; van der Arend, R

    2014-01-01

    Fat-containing food waste can be effectively treated in a new type of reactor, the so-called BIOPAQ-Anaerobic Flotation Reactor or BIOPAQ(®) anaerobic flotation reactor (AFR). In the reactor a flotation unit is integrated to retain the sludge. In this study results from two plants with a 430 and 511 m(3)-AFR, respectively, are presented. In one reactor, which is fed with water originating from different food liquid streams, over 99% of fat and oils were removed. Over 90% of the chemical oxygen demand (COD) was removed. When the last solids were removed from the effluent with a tilted plate settler, 98% COD removal was attained. The effluent concentrations of extractable hydrolysed and non-hydrolysed fats were less than 40 mg/l. Apparently the variations in the liquid streams deriving from the tank cleaning activities did not disturb the system. Only extremely high concentrations of fats could disturb the system, but the inhibition was reversible. In the reactor treating water from an ice-cream factory, which contained fats up to approximately 50% of influent COD, a COD removal efficiency of 90% was achieved. At volumetric loading rates varying from 1 to 8 kg COD/m(3)/d, biogas was produced at an average specific gas production of 0.69 m(3)/kg COD-removed.

  17. Anaerobic digestion of kitchen wastes in a single-phased anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO2

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; HE Zheng-guang; ZHANG Li-li; XU Jian-bo; SHI Hong-zhuan; CAI Wei-min

    2005-01-01

    The performance of the single-stage anaerobic digestion of kitchen wastes was investigated in an anaerobic sequencing batch reactor(ASBR) with gas-phased absorb of CO2. The ASBR was operated at four chemical oxygen demand(COD) loading rates, 2.8,respectively. The operation of the reactor with gas-phased absorb of CO2 was stable in spite of the low pH (2.6-3.9) and high concentration of TS(142 g/L) of input mixture. The output volatile fatty acid(VFA) concentration was between 2.7-4.7 g/L and had no inhibition on the methanogenic microorganism. The reactor without gas-phased absorb of CO2 became acidified when the total COD alkaline will be required to keep pH in the appropriate range for the methanogenic microorganism based on theoretical calculation. Gasphased absorb of CO2 effectively reduced the alkaline consumption, hence avoided excessive cation into the reactor.

  18. Solid anaerobic digestion batch with liquid digestate recirculation and wet anaerobic digestion of organic waste: Comparison of system performances and identification of microbial guilds.

    Science.gov (United States)

    Di Maria, Francesco; Barratta, Martino; Bianconi, Francesco; Placidi, Pisana; Passeri, Daniele

    2017-01-01

    Solid anaerobic digestion batch (SADB) with liquid digestate recirculation and wet anaerobic digestion of organic waste were experimentally investigated. SADB was operated at an organic loading rate (OLR) of 4.55kgVS/m(3)day, generating about 252NL CH4/kgVS, whereas the wet digester was operated at an OLR of 0.9kgVS/m(3)day, generating about 320NL CH4/kgVS. The initial total volatile fatty acids concentrations for SADB and wet digestion were about 12,500mg/L and 4500mg/L, respectively. There were higher concentrations of ammonium and COD for the SADB compared to the wet one. The genomic analysis performed by high throughput sequencing returned a number of sequences for each sample ranging from 110,619 to 373,307. More than 93% were assigned to the Bacteria domain. Seven and nine major phyla were sequenced for the SADB and wet digestion, respectively, with Bacteroidetes, Firmicutes and Proteobacteria being the dominant phyla in both digesters. Taxonomic profiles suggested a methanogenic pathway characterized by a relevant syntrophic acetate-oxidizing metabolism mainly in the liquid digestate of the SADB. This result also confirms the benefits of liquid digestate recirculation for improving the efficiency of AD performed with high solids (>30%w/w) content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Use of gamma-irradiation pretreatment for enhancement of anaerobic digestibility of sewage sludge

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of y-irradiation pretreatment on anaerobic digestibility of sewage sludge was investigated in this paper.Parameters like solid components,soluble components,and biogas production of anaerobic digestion experiment for sewage sludge were measured.The values of these parameters were compared before and after y-irradiation pretreatment.Total solid (TS),volatile solid (VS),suspended solid (SS),volatile suspended solid (VSS),and average floc size of samples decreased after γ-irradiation treatment.Besides,floc size distribution of sewage sludge shifted from 80-100 μm to 0-40 μm after y-irradiation treatment at the doses from 0 to 30 kGy,which indicated the disintegration of sewage sludge.Moreover,microbe cells of sewage sludge were ruptured by γ-irradiation treatment,which resulted in the release of cytoplasm and increase of soluble chemical oxygen demand (SCOD).Both sludge disintegration and microbe cells rupture enhanced the subsequent anaerobic digestion process,which was demonstrated by the increase of accumulated biogas production.Compared with digesters fed with none irradiated sludge,the accumulated biogas production increased 44,98,and 178 mL for digesters fed sludge irradiated at 2.48,6.51,and 11.24 kGy,respectively.The results indicated that "/-irradiation pretreatment could effectively enhance anaerobic digestibility of sewage sludge,and correspondingly,could accelerate hydrolysis process,shorten sludge retention time of sludge anaerobic digestion process.

  20. Preliminary experimental results of Sewage Sludge (SS) Co-digestion with Palm Oil Mill Effluent (POME) for Enhanced Biogas Production in Laboratory Scale Anaerobic Digester

    Science.gov (United States)

    Sivasankari, R.; Kumaran, P.; Normanbhay, Saifuddin; Halim Shamsuddin, Abd

    2013-06-01

    An investigation on the feasibility of co-digesting Sewage Sludge with Palm Oil Mill Effluent for enhancing the biogas production and the corresponding effect of the co-digestion substrate ratio on the biogas production has been evaluated. Anaerobic co-digestion of POME with SS was performed at ratios of 100:0, 70:30, 60:40 and 0:100 to find the optimum blend required for enhanced waste digestion and biogas production. Single stage batch digestion was carried out for 12 days in a laboratory scale anaerobic digester. Co-digestion of sludge's at the 70:30 proportion resulted in optimal COD and C: N ratio which subsequently recorded the highest performance with regards to biogas production at 28.1 L's compared to the 1.98 L's of biogas produced from digestion of SS alone. From the results obtained, it is evident that co-digestion of POME and SS is an attractive option to be explored for enhancement of biogas production in anaerobic digesters.

  1. Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiao, E-mail: liuxiao07@mails.tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China); Wang Wei; Shi Yunchun; Zheng Lei [School of Environment, Tsinghua University, Beijing 100084 (China); Gao Xingbao [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Qiao Wei [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhou Yingjun [Department of Urban and Environmental Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nisikyo-ku, Kyoto 615-8540 (Japan)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) was examined on a pilot-scale reactor. Black-Right-Pointing-Pointer System performance and stability under OLR of 1.2, 2.4, 3.6, 4.8, 6.0 and 8.0 kg VS (m{sup 3} d){sup -1} were analyzed. Black-Right-Pointing-Pointer A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and HRT of 15d. Black-Right-Pointing-Pointer With the increasing OLRs, pH values, VS removal rate and methane concentration decreased and VFA increased. Black-Right-Pointing-Pointer The changing of biogas production rate can be a practical approach to monitor and control anaerobic digestion system. - Abstract: The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2-8.0 kg volatile solid (VS) (m{sup 3} d){sup -1}, with VS reduction rates of 61.7-69.9%, and volumetric biogas production of 0.89-5.28 m{sup 3} (m{sup 3} d){sup -1}. A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m{sup 3} d){sup -1}. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.

  2. Two-phase anaerobic digestion of vegetable market waste fraction of municipal solid waste and development of improved technology for phase separation in two-phase reactor.

    Science.gov (United States)

    Majhi, Bijoy Kumar; Jash, Tushar

    2016-12-01

    Biogas production from vegetable market waste (VMW) fraction of municipal solid waste (MSW) by two-phase anaerobic digestion system should be preferred over the single-stage reactors. This is because VMW undergoes rapid acidification leading to accumulation of volatile fatty acids and consequent low pH resulting in frequent failure of digesters. The weakest part in the two-phase anaerobic reactors was the techniques applied for solid-liquid phase separation of digestate in the first reactor where solubilization, hydrolysis and acidogenesis of solid organic waste occur. In this study, a two-phase reactor which consisted of a solid-phase reactor and a methane reactor was designed, built and operated with VMW fraction of Indian MSW. A robust type filter, which is unique in its implementation method, was developed and incorporated in the solid-phase reactor to separate the process liquid produced in the first reactor. Experiments were carried out to assess the long term performance of the two-phase reactor with respect to biogas production, volatile solids reduction, pH and number of occurrence of clogging in the filtering system or choking in the process liquid transfer line. The system performed well and was operated successfully without the occurrence of clogging or any other disruptions throughout. Biogas production of 0.86-0.889m(3)kg(-1)VS, at OLR of 1.11-1.585kgm(-3)d(-1), were obtained from vegetable market waste, which were higher than the results reported for similar substrates digested in two-phase reactors. The VS reduction was 82-86%. The two-phase anaerobic digestion system was demonstrated to be stable and suitable for the treatment of VMW fraction of MSW for energy generation.

  3. Microbial electrolysis contribution to anaerobic digestion of waste activated sludge, leading to accelerated methane production

    DEFF Research Database (Denmark)

    Liu, Wenzong; Cai, Weiwei; Guo, Zechong

    2016-01-01

    Methane production rate (MPR) in waste activated sludge (WAS) digestion processes is typically limitedby the initial steps of complex organic matter degradation, leading to a limited MPR due to sludgefermentation speed of solid particles. In this study, a novel microbial electrolysis AD reactor (ME......-AD) wasused to accelerate methane production for energy recovery from WAS. Carbon bioconversion wasaccelerated by ME producing H2 at the cathode. MPR was enhanced to 91.8 gCH4/m3 reactor/d in themicrobial electrolysis ME-AD reactor, thus improving the rate by 3 times compared to control conditions (30.6 gCH4...

  4. Developmental Design of Anaerobic Wetland System for Mining Waste Water Treatment

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ashraf

    2011-01-01

    . Conclusion: The planting density chosen is based on similar research on constructed wetlands. Proposed anaerobic wetland is first of its kind introduce for mining waste water treatment in Malaysia. Good results have achieved on laboratory scale operations for this system.

  5. Enhanced Versus Conventional Sludge Anaerobic Processes: Performances and Techno-Economic Assessment.

    Science.gov (United States)

    Gianico, Andrea; Bertanza, Giorgio; Braguglia, Camilla M; Canato, Matteo; Gallipoli, Agata; Laera, Giuseppe; Levantesi, Caterina; Mininni, Giuseppe

    2016-05-01

    Sewage sludge processing is a key issue in water resource recovery facilities due to the inefficacy of conventional treatments to produce high quality biosolids to be safely used in agriculture. Under this framework, the performances of several enhanced stabilization processes, namely ultrasound-pretreated Mesophilic Anaerobic Digestion (US+MAD), thermophilic anaerobic digestion (TAD), thermal-pretreated TAD (TH+TAD) and ultrasound-pretreated inverse Temperature Phased Anaerobic Digestion (US+iTPAD) have been investigated. Such enhanced processes resulted in higher biogas yields and higher destruction of pathogens with respect to conventional MAD process, thus suggesting their feasibility in full-scale implementation perspectives. A procedure for technical-economic comparison of new sludge processing lines against conventional ones (benchmarking) was developed, based on the definition of technical issues (e.g. reliability, complexity, etc.) which are rated for each situation. Moreover, capital and operating costs were estimated. The enhanced processes analyzed in this work showed some potentially critical items, mainly related to energy balance and reagent consumption.

  6. Improve biogas production from low-organic-content sludge through high-solids anaerobic co-digestion with food waste.

    Science.gov (United States)

    Liu, Chuanyang; Li, Huan; Zhang, Yuyao; Liu, Can

    2016-11-01

    Anaerobic co-digestion of sewage sludge and food waste was tested at two different total solid (TS) concentrations. In the low-solids group with TS 4.8%, the biogas production increased linearly as the ratio of food waste in substrate increased from 0 to 100%, but no synergetic effect was found between the two substrates. Moreover, the additive food waste resulted in the accumulation of volatile fatty acids and decelerated biogas production. Thus, the blend ratio of food waste should be lower than 50%. While in the high-solids group with TS 14%, the weak alkaline environment with pH 7.5-8.5 avoided excessive acidification but high concentration of free ammonia was a potential risk. However, good synergetic effect was found between the two substrates because the added food waste improved mass transfer in sludge cake. Thus, 50% was recommended as the optimum ratio of food waste in substrate because of the best synergetic effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Pilot-scale gasification of municipal solid wastes by high-rate and two-phase anaerobic digestion (TPAD).

    Science.gov (United States)

    Ghosh, S; Henry, M P; Sajjad, A; Mensinger, M C; Arora, J L

    2000-01-01

    Bioconversion of municipal solid waste-sludge blend by conventional high-rate and two-phase anaerobic digestion was studied. RDF (refused-derived fuel)-quality feed produced in a Madison, Wisconsin, USA, MRF (materials-recovery facility) was used. High-rate digestion experiments were conducted with bench-scale digesters under target operating conditions developed from an economic feasibility study. The effects of digestion temperature, RDF content of digester feed, HRT, loading rate, RDF particle size, and RDF pretreatment with cellulase or dilute solutions of NaOH or lime on digester performance were studied. A pilot-scale two-phase digestion plant was operated with 80:20 (weight ratio) RDF-sludge blends to show that this process exhibited a higher methane yield, and produced a higher methane-content digester gas than those obtained by single-stage, high-rate anaerobic digestion.

  8. Dynamics of microbial community in a mesophilic anaerobic digester treating food waste: Relationship between community structure and process stability.

    Science.gov (United States)

    Li, Lei; He, Qin; Ma, Yao; Wang, Xiaoming; Peng, Xuya

    2015-01-01

    Organic loading rate (OLR) disturbances were introduced into a mesophilic anaerobic digester treating food waste (FW) to induce stable and deteriorative phases. The microbial community of each phase was investigated using 454-pyrosequencing. Results show that the relative abundance of acid-producing bacteria and syntrophic volatile fatty acid (VFA) oxidizers increased dramatically at deteriorative phase, while the dominant methanogens did not shift from acetoclastic to hydrogenotrophic groups. The mismatching between bacteria and methanogens may partially be responsible for the process deterioration. Moreover, the succession of predominant hydrogenotrophic methanogens reduced the consumption efficiency of hydrogen; meanwhile, the dominant Methanosaeta with low acetate degradation rate, and the increase of inhibitors concentrations further decreased its activity, which may be the other causes for the process failure. These results improve the understanding of the microbial mechanisms of process instability, and provide theoretical basis for the efficient and stable operation of anaerobic digester treating FW.

  9. Separate collection of household food waste for anaerobic degradation - Comparison of different techniques from a systems perspective.

    Science.gov (United States)

    Bernstad, A; la Cour Jansen, J

    2012-05-01

    Four systems for household food waste collection are compared in relation the environmental impact categories eutrophication potential, acidification potential, global warming potential as well as energy use. Also, a hotspot analysis is performed in order to suggest improvements in each of the compared collection systems. Separate collection of household food waste in paper bags (with and without drying prior to collection) with use of kitchen grinders and with use of vacuum system in kitchen sinks were compared. In all cases, food waste was used for anaerobic digestion with energy and nutrient recovery in all cases. Compared systems all resulted in net avoidance of assessed environmental impact categories; eutrophication potential (-0.1 to -2.4kg NO(3)(-)eq/ton food waste), acidification potential (-0.4 to -1.0kg SO(2)(-)eq/ton food waste), global warming potential (-790 to -960kg CO(2)(-)eq/ton food waste) and primary energy use (-1.7 to -3.6GJ/ton food waste). Collection with vacuum system results in the largest net avoidence of primary energy use, while disposal of food waste in paper bags for decentralized drying before collection result in a larger net avoidence of global warming, eutrophication and acidification. However, both these systems not have been taken into use in large scale systems yet and further investigations are needed in order to confirm the outcomes from the comparison. Ranking of scenarios differ largely if considering only emissions in the foreground system, indicating the importance of taking also downstream emissions into consideration when comparing different collection systems. The hot spot identification shows that losses of organic matter in mechanical pretreatment as well as tank connected food waste disposal systems and energy in drying and vacuum systems reply to the largest impact on the results in each system respectively.

  10. Microbial electrolysis contribution to anaerobic digestion of waste activated sludge, leading to accelerated methane production

    DEFF Research Database (Denmark)

    Liu, Wenzong; Cai, Weiwei; Guo, Zechong;

    2016-01-01

    Methane production rate (MPR) in waste activated sludge (WAS) digestion processes is typically limitedby the initial steps of complex organic matter degradation, leading to a limited MPR due to sludgefermentation speed of solid particles. In this study, a novel microbial electrolysis AD reactor (ME......-AD) wasused to accelerate methane production for energy recovery from WAS. Carbon bioconversion wasaccelerated by ME producing H2 at the cathode. MPR was enhanced to 91.8 gCH4/m3 reactor/d in themicrobial electrolysis ME-AD reactor, thus improving the rate by 3 times compared to control conditions (30.6 gCH4......-AD reactor allowed to significantly enhance carbon degradation and methaneproduction from WAS....

  11. Dry anaerobic digestion of food waste and cardboard at different substrate loads, solid contents and co-digestion proportions.

    Science.gov (United States)

    Capson-Tojo, Gabriel; Trably, Eric; Rouez, Maxime; Crest, Marion; Steyer, Jean-Philippe; Delgenès, Jean-Philippe; Escudié, Renaud

    2017-06-01

    The increasing food waste production calls for developing efficient technologies for its treatment. Anaerobic processes provide an effective waste valorization. The influence of the initial substrate load on the performance of batch dry anaerobic co-digestion reactors treating food waste and cardboard was investigated. The load was varied by modifying the substrate to inoculum ratio (S/X), the total solids content and the co-digestion proportions. The results showed that the S/X was a crucial parameter. Within the tested values (0.25, 1 and 4gVS·gVS(-1)), only the reactors working at 0.25 produced methane. Methanosarcina was the main archaea, indicating its importance for efficient methanogenesis. Acidogenic fermentation was predominant at higher S/X, producing hydrogen and other metabolites. Higher substrate conversions (≤48%) and hydrogen yields (≤62mL·gVS(-1)) were achieved at low loads. This study suggests that different value-added compounds can be produced in dry conditions, with the initial substrate load as easy-to-control operational parameter. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A mesocasm study of enhanced anaerobic biodegradation of petroleum hydrocarbons in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.; Guigard, S.; Biggar, K. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering; Foght, J.; Semple, K. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences

    2005-07-01

    Under certain conditions, Natural Attenuation (NA) processes can act to reduce the mass, toxicity, mobility, volume or concentrations of contaminants in soil or groundwater within a reasonable time frame. NA processes are considered to be a more cost-effective remediation approach than engineered processes. However, the rates of biodegradation in cold regions are slower and occasionally the processes are nutrient or Terminal Electron Acceptor (TEA) limited. These limitations may make NA less viable due to slower rates of biological activity. This paper discusses the results of a mesocasm study conducted in laboratory-controlled conditions to investigate the TEA and nutrient enhanced anaerobic biodegradation of petroleum hydrocarbons in groundwater from two sites in Alberta. Target compounds for the study were BTEX and the CCME F1 fraction. Samples taken from the site were used to set up 11 L mesocasms with a water to soil ratio of 10:1 under anaerobic conditions. The samples were amended with nitrate and sulfate and then incubated. Sub-sampling was carried out once a month to monitor substrate consumption, TEA depletion and evolution of biogenic gases. Microbial enumeration and metabolite analysis were also done. No final conclusions could be drawn from the study, which had only been carried out for 6 months at the time that this paper was written. However, results to date have indicated that the method of mesocasms and sub-sampling are applicable to anaerobic biodegradation studies. In addition, nutrient supplementation appears to enhance nitrate and sulfate reduction. However, the TEA depletion was greater than expected and could not be explained by the substrate consumption. Results also indicated that the groundwater from site 1 was sulfate-limited, suggesting that sulfate amendment could enhance anaerobic biodegradation of CCME F1 petroleum hydrocarbons. Data from the ongoing study may provide additional insight to clarify processes in the mesocasms. 9 refs

  13. Enhancement of sludge reduction and methane production by removing extracellular polymeric substances from waste activated sludge.

    Science.gov (United States)

    Nguyen, Minh Tuan; Mohd Yasin, Nazlina Haiza; Miyazaki, Toshiki; Maeda, Toshinari

    2014-12-01

    The management of waste activated sludge (WAS) recycling is a concern that affects the development of the future low-carbon society, particularly sludge reduction and biomass utilization. In this study, we investigated the effect of removing extracellular polymeric substances (EPS), which play important roles in the adhesion and flocculation of WAS, on increased sludge disintegration, thereby enhancing sludge reduction and methane production by anaerobic digestion. EPS removal from WAS by ethylenediaminetetraacetic acid (EDTA) significantly enhanced sludge reduction, i.e., 49 ± 5% compared with 27 ± 1% of the control at the end the digestion process. Methane production was also improved in WAS without EPS by 8881 ± 109 CH4 μmol g(-1) dry-weight of sludge. Microbial activity was determined by denaturing gradient gel electrophoresis and real-time polymerase chain reaction, which showed that the hydrolysis and acetogenesis stages were enhanced by pretreatment with 2% EDTA, with a larger methanogenic community and better methane production.

  14. 10. Biogas conference Dresden. Anaerobic treatment of biological wastes. Proceedings; 10. Biogastagung Dresden. Anaerobe biologische Abfallbehandlung. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    Dornack, Christina [Technische Univ. Dresden (Germany). Inst. fuer Abfallwirtschaft und Altlasten; Scholwin, Frank [Institut fuer Biogas, Kreislaufwirtschaft und Energie, Weimar (Germany); Liebetrau, Jan [Deutsches Biomasseforschungszentrum (DBFZ), Leipzig (Germany); Fassauer, Burkhardt [Fraunhofer-Institut fuer Keramische Technologien und Systeme (IKTS), Hermsdorf (Germany); Nelles, Michael (ed.) [Rostock Univ. (Germany). Lehrstuhl fuer Abfall- und Stoffstromwirtschaft

    2015-07-01

    The biogas conference in Dresden will be held for the tenth time and is still the only conference in Germany, which focuses on the production of biogas solely from waste. This year, the implementation of paragraph 11 of the Recycling and Waste Management Act and the amendment of the Renewable Energies Act (EEG) in 2014, the chances of the waste management biogas technology will be spotlighted here. The efficiency and wise use of the end products of the biogas production - the biogas and fermentation residues are equally critical for the success of biogas technology as the emission reduction of biogas plants. In this context, the biogas technology will also be dependent in the future on legal requirements and funding instruments such as the EEG. For the technical implementation, the development of reliable system concepts with specific sinking biogas and electricity supply costs and with greater flexibility in terms of launching needs-based biogas and electricity production. The contributions in this paper discuss possible solutions and implementations from the perspective of politics, associations, research and practice. Innovative topics will be discussed, which will be decisive for the future of biogas production from organic wastes. [German] Die Biogastagung in Dresden findet zum zehnten Mal statt und ist nach wie vor die einzige Tagung in Deutschland, welche die Biogaserzeugung ausschliesslich aus Reststoffen thematisiert. In diesem Jahr sollen vor dem Hintergrund der Umsetzung des paragraph 11 des Kreislaufwirtschaftswirtschaftsgesetzes und der Novellierung des EEG 2014 die Chancen der abfallwirtschaftlichen Biogastechnologie beleuchtet werden. Die effiziente und sinnvolle Nutzung der Endprodukte der Biogaserzeugung - des Biogases und des Gaerrests sind ebenso entscheidend fuer den Erfolg der Biogastechnologie wie die Emissionsminderung aus Biogasanlagen. In diesem Zusammenhang wird die Biogastechnologie auch zukuenftig auf gesetzliche Vorgaben und

  15. Anaerobic digestion of different organic wastes for biogas production and its operational control performed by the modified ADM1.

    Science.gov (United States)

    Zhou, Haidong; Li, Han; Wang, Fengfei

    2012-01-01

    Anaerobic digestion (AD) of different organic wastes for biogas production under variable operating conditions was simulated with a steady-state implementation of the modified IWA Anaerobic Digestion Model No. 1 (ADM1), and an input-output feedback control system using the model as a test platform was developed. The main aim of this study was to compare the characteristics of organic wastes in the AD processes and manage to keep the processes stable based on the results of simulation. The two important operating factors, solid retention time (SRT) and organic loading rate (OLR) (or the ratio of input flows for co-digestion), were investigated. Anaerobic digestion of biowaste was characterized with lower biogas production and instability of the processes, especially at OLR 2.5 kgCOD/m(3)·d or more, although longer SRT could increase the biogas production. Moreover, the co-substrate composed of biowaste and corn silage would lead to instability of the processes and much lower biogas production. Biowaste was, however, preferable to be co-digested with manures of living stock or sewage sludge. Manure could contribute to the stability of the AD processes, and its co-substrates with organic wastes rich in carbohydrates such as biowaste and corn silage would improve the biogas production and the proportion of methane. Longer SRTs would improve the biogas production from manure as well as its co-substrates except the co-substrate with biowaste as the production was not distinctly raised. The test of the developed input-output feedback control system showed that the control system could reject a realistic set of random disturbances and keep the AD processes stable under the desired operational conditions with a minimal use of measurement facilities.

  16. 厌氧消化在餐厨垃圾处理中的应用%Application of Anaerobic Digestion in Municipal Dietetic Organic Wastes

    Institute of Scientific and Technical Information of China (English)

    邹辉; 吴刚

    2011-01-01

    The theory and research status of anaerobic digestion technology in municipal dietetic organic waste were viewed with some references. By contrast, the merits of anaerobic digestion technology were discussed and method and application of anaerobic digestion technology were introduced. Meanwhile it presented the prospect of anaerobic digestion technology in municipal dietetic organic waste.%结合多篇参考文献,从原理和工艺的角度,综述了餐厨垃圾现有的一些处理方法,通过比较各种不同的处理方法,指出厌氧消化法处理的优势;重点论述了厌氧消化处理的方法和具体应用,并且展望其厌氧消化的研究前景.

  17. Anaerobic codigestion of municipal, farm, and industrial organic wastes: A survey of recent literature

    DEFF Research Database (Denmark)

    Alatriste-Mondragon, Felipe; Samar, P.; Cox, H.H.J.

    2006-01-01

    efficient use of equipment and cost-sharing by processing multiple waste streams in a single facility. Many municipal wastewater treatment plants (WWTPs) in industrialized countries currently process wastewater sludge in large digesters. Codigestion of organic wastes with municipal wastewater sludge can...... wastewater sludge, the organic fraction of municipal solid waste, and cattle manure (CAM) are the main wastes most often used in codigestion processes. Wastes that are codigested with these main wastes are wood wastes. industrial organic wastes, and farm wastes. These are referred to in this survey......Codigestion of organic wastes is a technology that is increasingly being applied for simultaneous treatment of several solid and liquid organic wastes. The main advantages of this technology are improved methane yield because of the supply of additional nutrients from the codigestates and more...

  18. Anaerobic treatment as a core technology for energy, nutrients and water recovery from source-separated domestic waste(water).

    Science.gov (United States)

    Zeeman, Grietje; Kujawa, Katarzyna; de Mes, Titia; Hernandez, Lucia; de Graaff, Marthe; Abu-Ghunmi, Lina; Mels, Adriaan; Meulman, Brendo; Temmink, Hardy; Buisman, Cees; van Lier, Jules; Lettinga, Gatze

    2008-01-01

    Based on results of pilot scale research with source-separated black water (BW) and grey water (GW), a new sanitation concept is proposed. BW and GW are both treated in a UASB (-septic tank) for recovery of CH4 gas. Kitchen waste is added to the anaerobic BW treatment for doubling the biogas production. Post-treatment of the effluent is providing recovery of phosphorus and removal of remaining COD and nitrogen. The total energy saving of the new sanitation concept amounts to 200 MJ/year in comparison with conventional sanitation, moreover 0.14 kg P/p/year and 90 litres of potential reusable water are produced.

  19. Anaerobic co-digestion of source segregated brown water (feces-without-urine) and food waste: For Singapore context

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, Rajinikanth, E-mail: rrajinime@yahoo.co.in [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore (Singapore); Lim, Jun Wei [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore (Singapore); Mao, Yu [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore (Singapore); School of Energy and Environmental Sciences, Yunnan Normal University, 121 Street, Kunming 650092 China (China); Chen, Chia-Lung [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore (Singapore); Wang, Jing-Yuan [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore)

    2013-01-15

    The objective of this study was to evaluate the feasibility of anaerobic co-digestion of brown water (BW) [feces-without-urine] and food waste (FW) in decentralized, source-separation-based sanitation concept. An effort has been made to separate the yellow water (urine) and brown water from the source (using no-mix toilet) primarily to facilitate further treatment, resource recovery and utilization. Batch assay analytical results indicated that anaerobic co-digestion [BW + FW] showed higher methane yield (0.54–0.59 L CH{sub 4}/gVS{sub added}) than BW or FW as a sole substrate. Anaerobic co-digestion was performed in the semi-continuously fed laboratory scale reactors viz. two-phase continuous stirred-tank reactor (CSTR) and single-stage sequencing-batch operational mode reactor (SeqBR). Initial 120 d of operation shows that SeqBR performed better in terms of organic matter removal and maximum methane production. At steady-state, CODs, CODt, VS removals of 92.0 ± 3.0, 76.7 ± 5.1 and 75.7 ± 6.6% were achieved for SeqBR at 16 d HRT, respectively. This corresponds to an OLR of 2–3 gCOD/L d and methane yield of about 0.41 L CH{sub 4}/gVS{sub added}. Good buffering capacity did not lead to accumulation of VFA, showing better process stability of SeqBR at higher loading rates. The positive findings show the great potential of applying anaerobic co-digestion of BW + FW for energy production and waste management. In addition, daily flush water consumption is reduced up to 80%. Decentralized, source-separation-based sanitation concept is expected to provide a practical solution for those countries experiencing rapid urbanization and water shortage issues, for instance Singapore. - Highlights: ► Source separation of organic waste/wastewater streams on household level was done. ► Brown water (BW) was collected from a specially designed no-mix toilet. ► BW and food waste codigestion proved as a potential substrate for biogas production. ► A distinct improvement

  20. Modelling the anaerobic digestion of solid organic waste – Substrate characterisation method for ADM1 using a combined biochemical and kinetic parameter estimation approach

    OpenAIRE

    Poggio, D.; Walker, M.; Nimmo, W; Ma, L; Pourkashanian, M.

    2016-01-01

    This work proposes a novel and rigorous substrate characterisation methodology to be used with ADM1\\ud to simulate the anaerobic digestion of solid organic waste. The proposed method uses data from both\\ud direct substrate analysis and the methane production from laboratory scale anaerobic digestion experiments\\ud and involves assessment of four substrate fractionation models. The models partition the organic\\ud matter into a mixture of particulate and soluble fractions with the decision on t...

  1. The effect of free nitrous acid on key anaerobic processes in enhanced biological phosphorus removal systems.

    Science.gov (United States)

    Ye, Liu; Pijuan, Maite; Yuan, Zhiguo

    2013-02-01

    In this study, the effect of nitrite/FNA on the anaerobic metabolism of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) is investigated. The results clearly show that FNA has a detrimental effect on the acetate uptake rate by both PAOs and GAOs, but this adverse effect is much stronger on PAOs than on GAOs. Also, when FNA was increased, phosphate release to acetate uptake ratio by PAOs increased substantially (250-300% compared to control), which was accompanied by decreases (40-60%) in glycogen degradation and PHA production to VFA uptake. In contrast, these ratios for GAOs remained constant or increased slightly towards the highest FNA concentration applied. These results indicate that the anaerobic metabolism of PAOs is more adversely affected than that of GAOs when FNA is present. This might provide a competitive advantage to GAOs over PAOs in enhanced biological phosphorus removal systems when nitrite is present. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid.

    Science.gov (United States)

    Li, Xiaoming; Zhao, Jianwei; Wang, Dongbo; Yang, Qi; Xu, Qiuxiang; Deng, Yongchao; Yang, Weiqiang; Zeng, Guangming

    2016-02-01

    Short-chain fatty acid (SCFA) production from waste activated sludge (WAS) anaerobic fermentation is often limited by the slow hydrolysis rate and poor substrate availability, thus a long fermentation time is required. This paper reports a new pretreatment approach, i.e., using free nitrous acid (FNA) to pretreat sludge, for significantly enhanced SCFA production. Experimental results showed the highest SCFA production occurred at 1.8 mg FNA/L with time of day 6, which was 3.7-fold of the blank at fermentation time of day 12. Mechanism studies revealed that FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. It was also found that FNA pretreatment benefited hydrolysis and acidification processes but inhibited the activities of methanogens, thereby promoting the yield of SCFA. In addition, the FNA pretreatment substantially stimulated the activities of key enzymes responsible for hydrolysis and acidification, which were consistent with the improvement of solubilization, hydrolysis and acidification of WAS anaerobic fermentation.

  3. Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: effect on sludge solubilisation and anaerobic digestion.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Lo, Shang-Lien; Rajpal, Ankur

    2014-05-01

    The effects of alkali-enhanced microwave (MW; 50-175 °C) and ultrasonic (US) (0.75 W/mL, 15-60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW-alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US-alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min-alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)-alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal-alkali treatment condition.

  4. Anaerobic codigestion of municipal, farm, and industrial organic wastes: A survey of recent literature

    DEFF Research Database (Denmark)

    Alatriste-Mondragon, Felipe; Samar, P.; Cox, H.H.J.

    2006-01-01

    wastewater sludge, the organic fraction of municipal solid waste, and cattle manure (CAM) are the main wastes most often used in codigestion processes. Wastes that are codigested with these main wastes are wood wastes. industrial organic wastes, and farm wastes. These are referred to in this survey...... as codigestates. The literature provides many laboratory studies (batch assays and bench-scale digesters) that assess the digestibility of codigestates and evaluate the performance and monitoring of codigestion, inhibition of digestion by codigestates, the design of the process (e.g., single-stage or two...

  5. 餐厨垃圾厌氧消化技术研究进展%Progress in anaerobic digestion technologies of food waste

    Institute of Scientific and Technical Information of China (English)

    贺雅静; 白红娟

    2012-01-01

    综合评述了厌氧消化技术研究进展。从脂肪及离子含量、温度、固含率及稀释率、接种物和接种量等方面对餐厨垃圾厌氧消化技术进行了介绍。%The research progress of anaerobic digestion technologies of food waste was summarized. Anaerobic digestion technologies of food waste were introduced in several aspects such as fat and ion content, temperature, solid concentration and dilution rate, the a- mount of inoculums and inoculation. This study provided a theoretical basis for the processing of anaerobic digestion of food waste.

  6. Microwave Enhanced Freeze Drying of Solid Waste Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of advanced methods for Microwave Enhanced Freeze Drying of Solid Waste (MEFDSW) is proposed. Methods for the recovery of relatively pure water as a...

  7. Methane production in anaerobic digestion of organic waste from Recife (Brazil landfill: evaluation in refuse of diferent ages

    Directory of Open Access Journals (Sweden)

    W. N. Schirmer

    2014-06-01

    Full Text Available This work focuses on monitoring the generation of biogas by biochemical methane potential (BMP assays, commonly used to assess anaerobic biodegradability of solid and liquid wastes under controlled conditions. The experiment employed 5 g of substrate of both refuses (fresh and one-year-old wastes, digested with 250 mL of inoculum in 1 L flasks as bioreactors (all of them in triplicate, operating under batch conditions at ± 35 ºC. Despite the difference of age of both refuses evaluated, there was no significant differences in volume (near 1800 mL and composition (55% methane of biogas generated in 80 days of incubation under mesophilic conditions. The important parameters of both refuses (such as moisture content, volatile solids and chemical oxygen demand also showed very similar initial values.

  8. Effect of anaerobic digestion on sequential pyrolysis kinetics of organic solid wastes using thermogravimetric analysis and distributed activation energy model.

    Science.gov (United States)

    Li, Xiaowei; Mei, Qingqing; Dai, Xiaohu; Ding, Guoji

    2017-03-01

    Thermogravimetric analysis, Gaussian-fit-peak model (GFPM), and distributed activation energy model (DAEM) were firstly used to explore the effect of anaerobic digestion on sequential pyrolysis kinetic of four organic solid wastes (OSW). Results showed that the OSW weight loss mainly occurred in the second pyrolysis stage relating to organic matter decomposition. Compared with raw substrate, the weight loss of corresponding digestate was lower in the range of 180-550°C, but was higher in 550-900°C. GFPM analysis revealed that organic components volatized at peak temperatures of 188-263, 373-401 and 420-462°C had a faster degradation rate than those at 274-327°C during anaerobic digestion. DAEM analysis showed that anaerobic digestion had discrepant effects on activation energy for four OSW pyrolysis, possibly because of their different organic composition. It requires further investigation for the special organic matter, i.e., protein-like and carbohydrate-like groups, to confirm the assumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Anaerobic digestion of Chinese cabbage waste silage with swine manure for biogas production: batch and continuous study.

    Science.gov (United States)

    Kafle, Gopi Krishna; Bhattarai, Sujala; Kim, Sang Hun; Chen, Lide

    2014-01-01

    The aim of this study was to investigate the potential for anaerobic co-digestion of Chinese cabbage waste silage (CCWS) with swine manure (SM). Batch and continuous experiments were carried out under mesophilic anaerobic conditions (36-38°C). The batch test evaluated the effect of CCWS co-digestion with SM (SM: CCWS=100:0; 25:75; 33:67; 0:100, % volatile solids (VS) basis). The continuous test evaluated the performance of a single stage completely stirred tank reactor with SM alone and with a mixture of SM and CCWS. Batch test results showed no significant difference in biogas yield up to 25-33% of CCWS; however, biogas yield was significantly decreased when CCWS contents in feed increased to 67% and 100%. When testing continuous digestion, the biogas yield at organic loading rate (OLR) of 2.0 g VSL⁻¹ d⁻¹ increased by 17% with a mixture of SM and CCWS (SM:CCWS=75:25) (423 mL g⁻¹ VS) than with SM alone (361 mL g⁻¹ VS). The continuous anaerobic digestion process (biogas production, pH, total volatile fatty acids (TVFA) and TVFA/total alkalinity ratios) was stable when co-digesting SM and CCWS (75:25) at OLR of 2.0 g VSL⁻¹ d⁻¹ and hydraulic retention time of 20 days under mesophilic conditions.

  10. Methane Production by Anaerobic Digestion of Food Wastes%餐厨垃圾厌氧发酵产甲烷综述

    Institute of Scientific and Technical Information of China (English)

    任维琰; 李勇; 顾广发

    2012-01-01

    针对餐厨垃圾厌氧发酵产甲烷过程,从工艺参数、工艺应用等方面阐述了国内外进展,并对餐厨垃圾厌氧发酵技术的规模化应用提出今后的研究方向.%In response to the methane production by anaerobic digestion of food wastes, the development in China and Abroad was discussedfrom the aspects of craft parameter and application. Future research directions for large-scale application of food waste anaerobic digestion wereproposed.

  11. Enhanced reductive dechlorination of polychlorinated biphenyl-contaminated soil by in-vessel anaerobic composting with zero-valent iron.

    Science.gov (United States)

    Long, Yu-Yang; Zhang, Chi; Du, Yao; Tao, Xiao-Qing; Shen, Dong-Sheng

    2014-03-01

    Anaerobic dechlorination is an effective degradation pathway for higher chlorinated polychlorinated biphenyls (PCBs). The enhanced reductive dechlorination of PCB-contaminated soil by anaerobic composting with zero-valent iron (ZVI) was studied, and preliminary reasons for the enhanced reductive dechlorination with ZVI were investigated. The results show that the addition of nanoscale ZVI can enhance dechlorination during in-vessel anaerobic composting. After 140 days, the average number of removed Cl per biphenyl with 10 mg g(-1) of added nanoscale ZVI was 0.63, enhancing the dechlorination by 34 % and improving the initial dechlorination speed. The ZVI enhances dechlorination by providing a suitable acid base environment, reducing volatile fatty acid inhibition and stimulating the microorganisms. The C/N ratios for treatments with the highest rate of ZVI addition were smaller than for the control, indicating that ZVI addition can promote compost maturity.

  12. Enhanced solid-state anaerobic digestion of corn stover by alkaline pretreatment.

    Science.gov (United States)

    Zhu, Jiying; Wan, Caixia; Li, Yebo

    2010-10-01

    Alkaline pretreatment was applied to enhance biogas production from corn stover through solid-state anaerobic digestion. Different NaOH loadings (1%, 2.5%, 5.0% and 7.5% (w/w)) were tested for solid-state pretreatment of corn stover. Lignin degradation during pretreatment increased from 9.1% to 46.2% when NaOH concentration increased from 1.0% to 7.5%. The NaOH-pretreated corn stover was digested using effluent of liquid anaerobic digestion as inoculum and nitrogen source. NaOH loading of 1% did not cause significant improvement on biogas yield. The highest biogas yield of 372.4 L/kg VS was obtained with 5% NaOH-pretreated corn stover, which was 37.0% higher than that of the untreated corn stover. However, a higher NaOH loading of 7.5% caused faster production of volatile fatty acids during the hydrolysis and acidogenesis stages, which inhibited the methanogenesis. Simultaneous NaOH treatment and anaerobic digestion did not significantly improve the biogas production (P>0.05).

  13. Enhanced phosphorus recovery and biofilm microbial community changes in an alternating anaerobic/aerobic biofilter.

    Science.gov (United States)

    Tian, Qing; Ong, Say Kee; Xie, Xuehui; Li, Fang; Zhu, Yanbin; Wang, Feng Rui; Yang, Bo

    2016-02-01

    The operation of an alternating anaerobic/aerobic biofilter (AABF), treating synthetic wastewater, was modified to enhance recovery of phosphorus (P). The AABF was periodically fed with an additional carbon source during the anaerobic phase to force the release of biofilm-sequestered P which was then harvested and recovered. A maximum of 48% of the total influent P was found to be released in the solution for recovery. Upon implementation of periodic P bio-sequestering and P harvesting, the predominant bacterial communities changed from β-Proteobacteria to γ-Proteobacteria groups. The genus Pseudomonas of γ-Proteobacteria was found to enrich greatly with 98% dominance. Dense intracellular poly-P granules were found within the cells of the biofilm, confirming the presence of P accumulating organisms (PAOs). Periodic addition of a carbon source to the AABF coupled with intracellular P reduction during the anaerobic phase most probably exerted environmental stress in the selection of Pseudomonas PAOs over PAOs of other phylogenic types. Results of the study provided operational information on the selection of certain microbial communities for P removal and recovery. This information can be used to further advance P recovery in biofilm systems such as the AABFs.

  14. Bioelectrochemically-assisted anaerobic composting process enhancing compost maturity of dewatered sludge with synchronous electricity generation.

    Science.gov (United States)

    Yu, Hang; Jiang, Junqiu; Zhao, Qingliang; Wang, Kun; Zhang, Yunshu; Zheng, Zhen; Hao, Xiaodi

    2015-10-01

    Bioelectrochemically-assisted anaerobic composting process (AnCBE) with dewatered sludge as the anode fuel was constructed to accelerate composting of dewatered sludge, which could increase the quality of the compost and harvest electric energy in comparison with the traditional anaerobic composting (AnC). Results revealed that the AnCBE yielded a voltage of 0.60 ± 0.02 V, and total COD (TCOD) removal reached 19.8 ± 0.2% at the end of 35 d. The maximum power density was 5.6 W/m(3). At the end of composting, organic matter content (OM) reduction rate increased to 19.5 ± 0.2% in AnCBE and to 12.9 ± 0.1% in AnC. The fuzzy comprehensive assessment (FCA) result indicated that the membership degree of class I of AnCBE compost (0.64) was higher than that of AnC compost (0.44). It was demonstrated that electrogenesis in the AnCBE could improve the sludge stabilization degree, accelerate anaerobic composting process and enhance composting maturity with bioelectricity generation.

  15. Determination of operational parameters of anaerobic phase for enhanced phosphorus removal in MBR

    Institute of Scientific and Technical Information of China (English)

    HE Sheng-bing; WANG Bao-zhen; WANG Lin; JIANG Yi-feng

    2004-01-01

    Two runs of experiments were carried out to obtain an understanding of phosphorus release and uptake under the anaerobic condition and then the aerobic condition respectively. Under anaerobic condition, it was found that the extent of phosphorus release appeared to increase with the increase of the initial organic loading rate when the initial organic loading rate was up to 0.1 gSCOD/gMLSS.When the initial organic loading rate was higher than 0.1 gSCOD/gMLSS, the amount of phosphorus release per unit mass of MLSS reached nearly a same stationary value, and it seemed this is not affected by organic loading rate when there is external available substrate remained. In addition, the effect of NOx-N on the phosphorus release and uptake was also investigated, it was proved that the denitrifiers has an advantage over polyphosphate accumulating bacteria in competition for organic substrate under anoxic condition. Therefore, the existence of NOx-N is disadvantageous to the phosphorus release. Based upon the above investigations, the process configuration of membrane bioreactor(MBR) in combination with anaerobic phase was proposed to enhance the removal of phosphorus in treating domestic wastewater. During the experimental period of four months, average removals of 92.50%, 84.25%, 100%, 94.09% and 85.33% were achieved for COD, TP, SS, NH3-N and TN respectively.

  16. Fouling of inorganic membrane and flux enhancement in membrane-coupled anaerobic bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.H.; Kang, I.J.; Lee, C.H. [Seoul National Univ. (Korea, Republic of). Dept. of Chemical Technology

    1999-03-01

    The fouling mechanism of an inorganic membrane was studied during the operation of a membrane-coupled anaerobic bioreactor (MCAB) when alcohol distillery wastewater was used as a digester feed. It was observed that the fouling mechanism of an inorganic membrane was significantly different from that of conventional membrane filtration processes. The main foulant was identified to be an inorganic precipitate, struvite (MgNH{sub 4}PO{sub 4}{center_dot}6H{sub 2}O), rather than anaerobic microbial flocs. Struvite appears to be precipitated not only on the membrane surface but also inside the membrane pores. The amount of struvite generated during the bioreaction was estimated to be about 2 g/L alcohol distillery wastewater. The inorganic foulant was not easily removed by general physical cleaning such as depressurization, lumen flushing, and backflushing. Based on these findings, the membrane fouling was alleviated and thus flux was enhanced by adopting a backfeeding mode which has dual purpose of feeding and backflushing with particle-free acidic wastewater used as the feed for anaerobic digestion.

  17. Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition.

    Science.gov (United States)

    Liu, Zhan-Guang; Zhou, Xue-Fei; Zhang, Ya-Lei; Zhu, Hong-Guang

    2012-01-01

    The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700m(3) chicken-manure continuous stirred tank reactor (CSTR). A 12.3L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35±1°C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5kg-COD/m(3)d over a hydraulic retention time of 1.5d, a maximum volumetric biogas production rate of 1.2m(3)/m(3)d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250mg/L) at an influent pH of 8.5-9.

  18. In-situ biogas upgrading during anaerobic digestion of food waste amended with walnut shell biochar at bench scale.

    Science.gov (United States)

    Linville, Jessica L; Shen, Yanwen; Ignacio-de Leon, Patricia A; Schoene, Robin P; Urgun-Demirtas, Meltem

    2017-06-01

    A modified version of an in-situ CO2 removal process was applied during anaerobic digestion of food waste with two types of walnut shell biochar at bench scale under batch operating mode. Compared with the coarse walnut shell biochar, the fine walnut shell biochar has a higher ash content (43 vs. 36 wt%) and higher concentrations of calcium (31 vs. 19 wt% of ash), magnesium (8.4 vs. 5.6 wt% of ash) and sodium (23.4 vs. 0.3 wt% of ash), but a lower potassium concentration (0.2 vs. 40% wt% of ash). The 0.96-3.83 g biochar (g VSadded)(-1) fine walnut shell biochar amended digesters produced biogas with 77.5%-98.1% CH4 content by removing 40%-96% of the CO2 compared with the control digesters at mesophilic and thermophilic temperature conditions. In a direct comparison at 1.83 g biochar (g VSadded)(-1), the fine walnut shell biochar amended digesters (85.7% CH4 content and 61% CO2 removal) outperformed the coarse walnut shell biochar amended digesters (78.9% CH4 content and 51% CO2 removal). Biochar addition also increased alkalinity as CaCO3 from 2800 mg L(-1) in the control digesters to 4800-6800 mg L(-1), providing process stability for food waste anaerobic digestion.

  19. Effect of chemo-mechanical disintegration on sludge anaerobic digestion for enhanced biogas production.

    Science.gov (United States)

    Kavitha, S; Pray, S Saji; Yogalakshmi, K N; Kumar, S Adish; Yeom, Ick-Tae; Banu, J Rajesh

    2016-02-01

    The effect of combined surfactant-dispersion pretreatment on dairy waste activated sludge (WAS) reduction in anaerobic digesters was investigated. The experiments were performed with surfactant, Sodium dodecyl sulfate (SDS) in the range of 0.01 to 0.1 g/g suspended solids (SS) and disperser with rpm of 5000-25,000. The COD (chemical oxygen demand) solubilization, suspended solids reduction, and biogas generation increased for an energy input of 7377 kJ/kg total solids (TS) (12,000 rpm, 0.04 g/g SS, and 30 min) and were found to be 38, 32, and 75 %, higher than that of control. The pretreated sludge improved the performance of semicontinuous anaerobic digesters of 4 L working volume operated at four different SRTs (sludge retention time). SRT of 15 days was found to be appropriate showing 49 and 51 % reduction in SS and volatile solids (VS), respectively. The methane yield of the pretreated sample was observed to be 50 mL/g VS removed which was observed to be comparatively higher than the control (12 mL/g VS removed) at optimal SRT of 15 days. To the best of the authors' knowledge, this study is the first to be reported and not yet been documented in literature.

  20. Enhancement of anaerobic biohydrogen/methane production from cellulose using heat-treated activated sludge.

    Science.gov (United States)

    Lay, C H; Chang, F Y; Chu, C Y; Chen, C C; Chi, Y C; Hsieh, T T; Huang, H H; Lin, C Y

    2011-01-01

    Anaerobic digestion is an effective technology to convert cellulosic wastes to methane and hydrogen. Heat-treatment is a well known method to inhibit hydrogen-consuming bacteria in using anaerobic mixed cultures for seeding. This study aims to investigate the effects of heat-treatment temperature and time on activated sludge for fermentative hydrogen production from alpha-cellulose by response surface methodology. Hydrogen and methane production was evaluated based on the production rate and yield (the ability of converting cellulose into hydrogen and methane) with heat-treated sludge as the seed at various temperatures (60-97 degrees C) and times (20-60 min). Batch experiments were conducted at 55 degrees C and initial pH of 8.0. The results indicate that hydrogen and methane production yields peaked at 4.3 mmol H2/g cellulose and 11.6 mmol CH4/g cellulose using the seed activated sludge that was thermally treated at 60 degrees C for 40 min. These parameter values are higher than those of no-treatment seed (HY 3.6 mmol H2/g cellulose and MY 10.4 mmol CH4/g cellulose). The maximum hydrogen production rate of 26.0 mmol H2/L/d and methane production rate of 23.2 mmol CH4/L/d were obtained for the seed activated sludge that was thermally treated at 70 degrees C for 50 min and 60 degrees C for 40 min, respectively.

  1. A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater.

    Science.gov (United States)

    Zhang, Yaobin; Jing, Yanwen; Quan, Xie; Liu, Yiwen; Onu, Pascal

    2011-01-01

    Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH(4) content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe(2+) released from ZVI served as a flocculent.

  2. THE EFFECT OF F/M RATIO TO THE ANAEROBIC DECOMPOSITION OF BIOGAS PRODUCTION FROM FISH OFFAL WASTE

    Directory of Open Access Journals (Sweden)

    Agus Hadiyarto

    2016-01-01

    Full Text Available Biogas is a gas produced from the anaerobic decomposition of organic compounds. In the production of biogas from anaerobic digestion, value of F/M ratio shows a ratio between the mass of food available in the waste substrate with a mass of microorganisms that act as decomposers. F/M ratio is too small causing microbes could not metabolize perfectly and vice versa on the value of the ratio F / M overload resulting metabolic imbalance. The purpose of this study was to assess the effect of F/M ratio to optimal production of biogas from fish offal waste. The process of anaerobic digestion is conducted in the biodigester with four-liter volume and batch system operated at ambient temperature for 38 days. As a raw material, fish offal and microbial sludge obtained from the curing of fish and river mud discharges in the region of Bandarharjo, Semarang, Central Java. F/M ratio is set at 0.2, 0.4, and 0.6 are derived from sewage sludge VSS weight ratio of fish offal with sludge containing microbes. The addition of micronutrients supplied with a concentration of 0.4 mg/liter. Yield maximum methane gas obtained was 164,7 l/kg CODMn when the ratio F/M was 0.2. Based on the results of the study, found that the ratio F/M affect the amount of biogas produced. Meanwhile, the retention time (HRT is only influenced by the ratio F/M.

  3. Enhancement of starting up anaerobic digestion of lignocellulosic substrate: fique's bagasse as an example.

    Science.gov (United States)

    Quintero, Mabel; Castro, Liliana; Ortiz, Claudia; Guzmán, Carolina; Escalante, Humberto

    2012-03-01

    In Colombia there are 20,000 ha of fique fields (Furcraea sp., family Agavaceae), that produce around 93,400 tons of fique's bagasse per year. These residuals are disposed into rivers and soil causing pollution. According to physicochemical characteristics, the lignocellulosic residues from fique crops (fique's bagasse) are appropriate carbon source to biogas production. Anaerobic digestion from fique's Bagasse (FB) requires a specialized microbial consortium capable of degrading its high lignocellulosic concentration. In this study, the capacities of seven microbial consortia for biomethane potential (BMP) from FB were evaluated. Inoculum of ruminal liquid achieved high hydrolytic activity (0.068 g COD/g VSS day), whereas pig waste sludge inoculum showed high methanogenic activity (0.146 g COD/g VSS day). Mixtures of these two inoculums (RL+PWS) showed the best yields for biomethane potential (0.3 m(3) CH4/Kg VS ad).

  4. Bioelectrochemical enhancement of methane production in low temperature anaerobic digestion at 10 °C.

    Science.gov (United States)

    Liu, Dandan; Zhang, Lei; Chen, Si; Buisman, Cees; Ter Heijne, Annemiek

    2016-08-01

    Anaerobic digestion at low temperature is an attractive technology especially in moderate climates, however, low temperature results in low microbial activity and low rates of methane formation. This study investigated if bioelectrochemical systems (BESs) can enhance methane production from organic matter in low-temperature anaerobic digestion (AD). A bioelectrochemical reactor was operated with granular activated carbon as electrodes at 10 °C. Our results showed that bioelectrochemical systems can enhance CH4 yield, accelerate CH4 production rate and increase acetate removal efficiency at 10 °C. The highest CH4 yield of 31 mg CH4-COD/g VSS was achieved in the combined BES-AD system at a cathode potential of -0.90 V (Ag/AgCl), which was 5.3-6.6 times higher than that in the AD reactor at 10 °C. CH4 production rate achieved in the combined BES-AD system at 10 °C was only slightly lower than that in the AD reactor at 30 °C. The presence of an external circuit between the acetate-oxidizing bioanode and methane-producing cathode provided an alternative pathway from acetate via electrons to methane, potentially via hydrogen. This alternative pathway seems to result in higher CH4 production rates at low temperature compared with traditional methanogenesis from acetate. Integration of BES with AD could therefore be an attractive alternative strategy to enhance the performance of anaerobic digestion in cold areas.

  5. A novel free ammonia based pretreatment technology to enhance anaerobic methane production from primary sludge.

    Science.gov (United States)

    Wei, Wei; Zhou, Xu; Xie, Guo-Jun; Duan, Haoran; Wang, Qilin

    2017-10-01

    This study proposed a novel free ammonia (FA, i.e., NH3 ) pretreatment technology to enhance anaerobic methane production from primary sludge for the first time. The solubilization of primary sludge was substantially enhanced following 24 h FA pretreatment (250-680 mg NH3 -N/L), by which the release of soluble chemical oxygen demand (SCOD) (i.e., 0.4 mg SCOD/mg VS added; VS: volatile solids) was approximately 10 times as much as that without pretreatment (i.e., 0.03 mg SCOD/mg VS added). Then, biochemical methane potential (BMP) tests demonstrated that FA pretreatment of 250-680 mg NH3 -N/L was capable of enhancing anaerobic methane production while the digestion time was more than 7 days. Model based analysis indicated that the improved anaerobic methane production was due to an increased biochemical methane potential (B0 ) of 8-17% (i.e., from 331 to 357-387 L CH4 /kg VS added), with the highest B0 achieved at 420 mg NH3 -N/L pretreatment. However, FA pretreatment of 250-680 mg NH3 -N/L decreased hydrolysis rate (k) by 24-38% compared with control (i.e., from 0.29 d(-1) to 0.18-0.22 d(-1) ), which explained the lower methane production over the first 7 days' digestion period. Economic analysis and environmental evaluation demonstrated that FA pretreatment technology was environmentally friendly and economically favorable. Biotechnol. Bioeng. 2017;114: 2245-2252. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Beyond land application: Emerging technologies for the treatment and reuse of anaerobically digested agricultural and food waste.

    Science.gov (United States)

    Sheets, Johnathon P; Yang, Liangcheng; Ge, Xumeng; Wang, Zhiwu; Li, Yebo

    2015-10-01

    Effective treatment and reuse of the massive quantities of agricultural and food wastes generated daily has the potential to improve the sustainability of food production systems. Anaerobic digestion (AD) is used throughout the world as a waste treatment process to convert organic waste into two main products: biogas and nutrient-rich digestate, called AD effluent. Biogas can be used as a source of renewable energy or transportation fuels, while AD effluent is traditionally applied to land as a soil amendment. However, there are economic and environmental concerns that limit widespread land application, which may lead to underutilization of AD for the treatment of agricultural and food wastes. To combat these constraints, existing and novel methods have emerged to treat or reuse AD effluent. The objective of this review is to analyze several emerging methods used for efficient treatment and reuse of AD effluent. Overall, the application of emerging technologies is limited by AD effluent composition, especially the total solid content. Some technologies, such as composting, use the solid fraction of AD effluent, while most other technologies, such as algae culture and struvite crystallization, use the liquid fraction. Therefore, dewatering of AD effluent, reuse of the liquid and solid fractions, and land application could all be combined to sustainably manage the large quantities of AD effluent produced. Issues such as pathogen regrowth and prevalence of emerging organic micro-pollutants are also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Economic screening of renewable energy technologies: Incineration, anaerobic digestion, and biodiesel as applied to waste water scum.

    Science.gov (United States)

    Anderson, Erik; Addy, Min; Ma, Huan; Chen, Paul; Ruan, Roger

    2016-12-01

    In the U.S., the total amount of municipal solid waste is continuously rising each year. Millions of tons of solid waste and scum are produced annually that require safe and environmentally sound disposal. The availability of a zero-cost energy source like municipal waste scum is ideal for several types of renewable energy technologies. However, the way the energy is produced, distributed and valued also contributes to the overall process sustainability. An economic screening method was developed to compare the potential energy and economic value of three waste-to-energy technologies; incineration, anaerobic digestion, and biodiesel. A St. Paul, MN wastewater treatment facility producing 3175 "wet" kilograms of scum per day was used as a basis of the comparison. After applying all theoretically available subsidies, scum to biodiesel was shown to have the greatest economic potential, valued between $491,949 and $610,624/year. The incineration of scum yielded the greatest reclaimed energy potential at 29billion kilojoules/year. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Effect of aerobic pre-treatment on hydrogen and methane production in a two-stage anaerobic digestion process using food waste with different compositions.

    Science.gov (United States)

    Rafieenia, Razieh; Girotto, Francesca; Peng, Wei; Cossu, Raffaello; Pivato, Alberto; Raga, Roberto; Lavagnolo, Maria Cristina

    2017-01-01

    Aerobic pre-treatment was applied prior to two-stage anaerobic digestion process. Three different food wastes samples, namely carbohydrate rich, protein rich and lipid rich, were prepared as substrates. Effect of aerobic pre-treatment on hydrogen and methane production was studied. Pre-aeration of substrates showed no positive impact on hydrogen production in the first stage. All three categories of pre-aerated food wastes produced less hydrogen compared to samples without pre-aeration. In the second stage, methane production increased for aerated protein rich and carbohydrate rich samples. In addition, the lag phase for carbohydrate rich substrate was shorter for aerated samples. Aerated protein rich substrate yielded the best results among substrates for methane production, with a cumulative production of approximately 351ml/gVS. With regard to non-aerated substrates, lipid rich was the best substrate for CH4 production (263ml/gVS). Pre-aerated P substrate was the best in terms of total energy generation which amounted to 9.64kJ/gVS. This study revealed aerobic pre-treatment to be a promising option for use in achieving enhanced substrate conversion efficiencies and CH4 production in a two-stage AD process, particularly when the substrate contains high amounts of proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Study of microbial community and biodegradation efficiency for single- and two-phase anaerobic co-digestion of brown water and food waste.

    Science.gov (United States)

    Lim, J W; Chen, C-L; Ho, I J R; Wang, J-Y

    2013-11-01

    The objective of this work was to study the microbial community and reactor performance for the anaerobic co-digestion of brown water and food waste in single- and two-phase continuously stirred tank reactors (CSTRs). Bacterial and archaeal communities were analyzed after 150 days of reactor operation. As compared to single-phase CSTR, methane production in two-phase CSTR was found to be 23% higher. This was likely due to greater extent of solubilization and acidification observed in the latter. These findings could be attributed to the predominance of Firmicutes and greater bacterial diversity in two-phase CSTR, and the lack of Firmicutes in single-phase CSTR. Methanosaeta was predominant in both CSTRs and this correlated to low levels of acetate in their effluent. Insights gained from this study would enhance the understanding of microorganisms involved in co-digestion of brown water and food waste as well as the complex biochemical interactions promoting digester stability and performance.

  10. Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

    Energy Technology Data Exchange (ETDEWEB)

    Ariunbaatar, Javkhlan, E-mail: jaka@unicas.it [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Scotto Di Perta, Ester [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy); Panico, Antonio [Telematic University PEGASO, Piazza Trieste e Trento, 48, 80132 Naples (Italy); Frunzo, Luigi [Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Via Claudio, 21, 80125 Naples (Italy); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); Lens, Piet N.L. [UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Pirozzi, Francesco [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy)

    2015-04-15

    Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC{sub 50} of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid.

  11. Anaerobic phosphate release from activated sludge with enhanced biological phosphorus removal. A possible mechanism of intracellular pH control

    Energy Technology Data Exchange (ETDEWEB)

    Bond, P.L.; Keller, J.; Blackall, L.L. [Univ. of Queensland, Brisbane (Australia)

    1999-06-05

    The biochemical mechanisms of the wastewater treatment process known as enhanced biological phosphorus removal (EBPR) are presently described in a metabolic model. The authors investigated details of the EBPR model to determine the nature of the anaerobic phosphate release and how this may be metabolically associated with polyhydroxyalkanoate (PHA) formation. Iodoacetate, an inhibitor of glycolysis, was found to inhibit the anaerobic formation of PHA and phosphate release, supporting the pathways proposed in the EBPR metabolic model. In the metabolic model, it is proposed that polyphosphate degradation provides energy for the microorganisms in anaerobic regions of these treatment systems. Other investigations have shown that anaerobic phosphate release depends on the extracellular pH. The authors observed that when the intracellular pH of EBPR sludge was raised, substantial anaerobic phosphate release was caused without volatile fatty acid (VFA) uptake. Acidification of the sludge inhibited anaerobic phosphate release even in the presence of VFA. from these observations, the authors postulate that an additional possible role of anaerobic polyphosphate degradation in EBPR is for intracellular pH control. Intracellular pH control may be a metabolic feature of EBPR, not previously considered, that could have some use in the control and optimization of EBPR.

  12. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

    Science.gov (United States)

    Grübel, Klaudiusz; Suschka, Jan

    2015-05-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

  13. Effects of sludge recirculation rate and mixing time on performance of a prototype single-stage anaerobic digester for conversion of food wastes to biogas and energy recovery.

    Science.gov (United States)

    Ratanatamskul, Chavalit; Saleart, Tawinan

    2016-04-01

    Food wastes have been recognized as the largest waste stream and accounts for 39.25 % of total municipal solid waste in Thailand. Chulalongkorn University has participated in the program of in situ energy recovery from food wastes under the Ministry of Energy (MOE), Thailand. This research aims to develop a prototype single-stage anaerobic digestion system for biogas production and energy recovery from food wastes inside Chulalongkorn University. Here, the effects of sludge recirculation rate and mixing time were investigated as the main key parameters for the system design and operation. From the results obtained in this study, it was found that the sludge recirculation rate of 100 % and the mixing time of 60 min per day were the most suitable design parameters to achieve high efficiencies in terms of chemical oxygen demand (COD), total solids (TS), and total volatile solid (TVS) removal and also biogas production by this prototype anaerobic digester. The obtained biogas production was found to be 0.71 m(3)/kg COD and the composition of methane was 61.6 %. Moreover, the efficiencies of COD removal were as high as 82.9 % and TVS removal could reach 83.9 % at the optimal condition. Therefore, the developed prototype single-stage anaerobic digester can be highly promising for university canteen application to recover energy from food wastes via biogas production.

  14. Toxicants inhibiting anaerobic digestion: a review.

    Science.gov (United States)

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  15. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  16. Chain elongation in anaerobic reactor microbiomes to recover resources from waste

    NARCIS (Netherlands)

    Spirito, C.M.; Richter, H.; Rabaey, K.; Stams, A.J.M.; Angenent, L.T.

    2014-01-01

    Different microbial pathways can elongate the carbon chains of molecules in open cultures of microbial populations (i.e. reactor microbiomes) under anaerobic conditions. Here, we discuss three such pathways: 1. homoacetogenesis to combine two carbon dioxide molecules into acetate; 2. succinate forma

  17. Biogas production from food-processing industrial wastes by anaerobic digestion

    DEFF Research Database (Denmark)

    Fang, Cheng

    Konfronteret med energikrise og klimaforandringer, har verden brug for grønne, effektive og kulstofneutrale energikilder, som kan erstatte fossile brændstoffer. Biogas, som dannes ved anaerob nedbrydning af organisk materiale, er en bæredygtig, pålidelig og vedvarende energikilde. Der er stor...

  18. Can aquatic worms enhance methane production from waste activated sludge?

    Science.gov (United States)

    Serrano, Antonio; Hendrickx, Tim L G; Elissen, Hellen H J; Laarhoven, Bob; Buisman, Cees J N; Temmink, Hardy

    2016-07-01

    Although literature suggests that aquatic worms can help to enhance the methane production from excess activated sludge, clear evidence for this is missing. Therefore, anaerobic digestion tests were performed at 20 and at 30°C with sludge from a high-loaded membrane bioreactor, the aquatic worm Lumbriculus variegatus, feces from these worms and with mixtures of these substrates. A significant synergistic effect of the worms or their feces on methane production from the high-loaded sludge or on its digestion rate was not observed. However, a positive effect on low-loaded activated sludge, which generally has a lower anaerobic biodegradability, cannot be excluded. The results furthermore showed that the high-loaded sludge provides an excellent feed for L. variegatus, which is promising for concepts where worm biomass is considered a resource for technical grade products such as coatings and glues.

  19. The effect of moisture regimes on the anaerobic degradation of municipal solid waste from Metepec (México).

    Science.gov (United States)

    Hernández-Berriel, Ma C; Márquez-Benavides, L; González-Pérez, D J; Buenrostro-Delgado, O

    2008-01-01

    The State of México, situated in central México, has a population of about 14 million, distributed in approximately 125 counties. Solid waste management represents a serious and ongoing pressure to local authorities. The final disposal site ("El Socavón") does not comply with minimum environmental requirements as no liners or leachate management infrastructure are available. Consequently, leachate composition or the effects of rain water input on municipal solid waste degradation are largely unknown. The aim of this work was to monitor the anaerobic degradation of municipal solid waste (MSW), simulating the water addition due to rainfall, under two different moisture content regimes (70% and 80% humidity). The study was carried out using bioreactors in both laboratory and pilot scales. The variation of organic matter and pH was followed in the solid matrix of the MSW. The leachate produced was used to estimate the field capacity of the MSW and to determine the pH, COD, BOD and heavy metals. Some leachate parameters were found to be within permitted limits, but further research is needed in order to analyze the leachate from lower layers of the disposal site ("El Socavón").

  20. Safety Enhancements for TRU Waste Handling - 12258

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Curt N. [Perma-Fix Northwest Richland, Inc., Richland, WA 99354 (United States)

    2012-07-01

    For years, proper Health Physics practices and 'As Low As Reasonably Achievable' (ALARA) principles have fostered the use of glove boxes or other methods of handling (without direct contact) high activities of radioactive material. The physical limitations of using glove boxes on certain containers have resulted in high-activity wastes being held in storage awaiting a path forward. Highly contaminated glove boxes and other remote handling equipment no longer in use have also been added to the growing list of items held for storage with no efficient method of preparation for proper disposal without creating exposure risks to personnel. This is especially true for wastes containing alpha-emitting radionuclides such as Plutonium and Americium that pose significant health risks to personnel if these Transuranic (TRU) wastes are not controlled effectively. Like any good safety program or root cause investigation PFNW has found that the identification of the cause of a negative change, if stopped, can result in a near miss and lessons learned. If this is done in the world of safety, it is considered a success story and is to be shared with others to protect the workers. PFNW believes that the tools, equipment and resources have improved over the past number of years but that the use of them has not progressed at the same rate. If we use our tools to timely identify the effect on the work environment and immediately following or possibly even simultaneously identify the cause or some of the causal factors, we may have the ability to continue to work rather than succumb to the start and stop-work mentality trap that is not beneficial in waste minimization, production efficiency or ALARA. (authors)

  1. The microbial ecology of anaerobic cellulose degradation in municipal waste landfill sites: evidence of a role for fibrobacters.

    Science.gov (United States)

    McDonald, James E; Houghton, James N I; Rooks, David J; Allison, Heather E; McCarthy, Alan J

    2012-04-01

    Cellulose is reputedly the most abundant organic polymer in the biosphere, yet despite the fundamental role of cellulolytic microorganisms in global carbon cycling and as potential sources of novel enzymes for biotechnology, their identity and ecology is not well established. Cellulose is a major component of landfill waste and its degradation is therefore a key feature of the anaerobic microbial decomposition process. Here, we targeted a number of taxa containing known cellulolytic anaerobes (members of the bacterial genus Fibrobacter, lineages of Clostridium clusters I, III, IV and XIV, and anaerobic fungi of the Neocallimastigales) in landfill leachate and colonized cellulose 'baits' via PCR and quantitative PCR (qPCR). Fibrobacter spp. and Clostridium clusters III, IV and XIV were detected in almost all leachate samples and cluster III and XIV clostridia were the most abundant (1-6% and 1-17% of total bacterial 16S rRNA gene copies respectively). Two landfill leachate microcosms were constructed to specifically assess those microbial communities that colonize and degrade cellulose substrates in situ. Scanning electron microscopy (SEM) of colonized cotton revealed extensive cellulose degradation in one microcosm, and Fibrobacter spp. and Clostridium cluster III represented 29% and 17%, respectively, of total bacterial 16S rRNA gene copies in the biofilm. Visible cellulose degradation was not observed in the second microcosm, and this correlated with negligible relative abundances of Clostridium cluster III and Fibrobacter spp. (≤ 0.1%), providing the first evidence that the novel fibrobacters recently detected in landfill sites and other non-gut environments colonize and degrade cellulose substrates in situ. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  2. Potential for anaerobic conversion of xenobiotics

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank

    2003-01-01

    regarding the treatment of xenobiotics is shown with the focus on the UASB reactor, but the applicability of other reactor designs for treatment of hazardous waste is also included. Bioaugmentation has proved to be a viable technique to enhance a specific activity in anaerobic reactors and recent research...

  3. A novel alternate feeding mode for semi-continuous anaerobic co-digestion of food waste with chicken manure.

    Science.gov (United States)

    Wang, Ming; Sun, Xianli; Li, Pengfei; Yin, Lili; Liu, Dan; Zhang, Yingwei; Li, Wenzhe; Zheng, Guoxiang

    2014-07-01

    A novel alternate feeding mode was introduced to study the possibilities of improving methane yield from anaerobic co-digestion of food waste (FW) with chicken manure (CM). Two kinds of feeding sequence (a day FW and next day CM (FM/CM), two days FM and the third day CM (FW/FM/CM)) were investigated in semi-continuous anaerobic digestion and lasted 225 days, and the mono-digestions of FW and CM were used as control group, respectively. The feeding sequence of FW/CM and mono-digestion of CM were observed to fail to produce gas at hydraulic retention time (HRT) of 70 days due to the ammonia inhibition, however, the mode of FW/FM/CM was proved to successfully run at HRT of 35 days with a higher OLR of 2.50 kg L(-1)d(-1) and obtain a higher methane production rate of 507.58 ml g(-1) VS and volumetric biogas production rate of 2.1 L L(-1)d(-1).

  4. Innovative ammonia stripping with an electrolyzed water system as pretreatment of thermally hydrolyzed wasted sludge for anaerobic digestion.

    Science.gov (United States)

    Park, Seyong; Kim, Moonil

    2015-01-01

    In this study, the anaerobic digestion of thermally hydrolyzed wasted sludge (THWS) with a high concentration of ammonia was carried out through combining with an ammonia stripping and an electrolyzed water system (EWS). The EWS produced acidic water (pH 2-3) at the anode and alkaline water (pH 11-12) at the cathode with an electro-diaphragm between the electrodes that could be applied to ammonia stripping. The ammonia stripping efficiency was strongly dependent on the pH and aeration rate, and the ammonium ion removal rate followed pseudo-first-order kinetics. From the BMP test, the methane yield of THWS after ammonia stripping using the EWS was 2.8 times higher than that of the control process (raw THWS without ammonia stripping). Furthermore, both methane yield and ammonium removal efficiency were higher in this study than in previous studies. Since ammonia stripping with the EWS does not require any chemicals for pH control, no precipitated sludge is produced and anaerobic microorganisms are not inhibited by cations. Therefore, ammonia stripping using the EWS could be an effective method for digestion of wastewater with a high concentration of ammonium nitrogen.

  5. The effects of different mixing intensities during anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Lindmark, Johan; Eriksson, Per; Thorin, Eva

    2014-08-01

    Mixing inside an anaerobic digester is often continuous and is not actively controlled. The selected mixing regime can however affect both gas production and the energy efficiency of the biogas plant. This study aims to evaluate these effects and compare three different mixing regimes, 150 RPM and 25 RPM continuous mixing and minimally intermittent mixing for both digestion of fresh substrate and post-digestion of the organic fraction of municipal solid waste. The results show that a lower mixing intensity leads to a higher biogas production rate and higher total biogas production in both cases. 25 RPM continuous mixing and minimally intermittent mixing resulted in similar biogas production after process stabilization, while 150 RPM continuous mixing resulted in lower production throughout the experiment. The lower gas production at 150 RPM could not be explained by the inhibition of volatile fatty acids. Cumulative biogas production until day 31 was 295 ± 2.9, 317 ± 1.9 and 304 ± 2.8N ml/g VS added during digestion of fresh feed and 113 ± 1.3, 134 ± 1.1 and 130 ± 2.3N ml/g VS added during post digestion for the 150 RPM, 25 RPM and minimally mixed intensities respectively. As well as increasing gas production, optimal mixing can improve the energy efficiency of the anaerobic digestion process.

  6. Microbial aspects of the formation of malodorous compounds in anaerobically stored piggery wastes

    NARCIS (Netherlands)

    Spoelstra, S.F.

    1978-01-01

    In modern intensive animal farming labour-saving waste handling systems are applied. As such, slatted floors have found wide application. In this system large amounts of malodorous wastes are stored in pits under the slatted floors, resulting in the emission of malodours with the ventilation air.

  7. The effect of system parameters on the biogas production from anaerobic digestion of livestock wastes

    Science.gov (United States)

    Animal wastes can serve as the feedstock for biogas production (mainly methane) that could be used as alternative energy source. The green energy derived from animal wastes is considered to be carbon neutral and offsetting those generated from fossil fuels. In this study, an evaluation of system p...

  8. Microbial aspects of the formation of malodorous compounds in anaerobically stored piggery wastes

    NARCIS (Netherlands)

    Spoelstra, S.F.

    1978-01-01

    In modern intensive animal farming labour-saving waste handling systems are applied. As such, slatted floors have found wide application. In this system large amounts of malodorous wastes are stored in pits under the slatted floors, resulting in the emission of malodours with the ventilation air. Co

  9. Pretreatment of food waste with high voltage pulse discharge towards methane production enhancement.

    Science.gov (United States)

    Zou, Lianpei; Ma, Chaonan; Liu, Jianyong; Li, Mingfei; Ye, Min; Qian, Guangren

    2016-12-01

    Anaerobic batch tests were performed to investigate the methane production enhancement and solid transformation rates from food waste (FW) by high voltage pulse discharge (HVPD) pretreatment. The total cumulative methane production with HVPD pretreatment was 134% higher than that of the control. The final volatile solids transformation rates of FW with and without HVPD pretreatment were 54.3% and 32.3%, respectively. Comparison study on HVPD pretreatment with acid, alkali and ultrasonic pretreatments showed that the methane production and COD removal rates of FW pretreated with HVPD were more than 100% higher than the control, but only about 50% higher can be obtained with other pretreatments. HVPD pretreatment could be a promising pretreatment method in the application of energy recovery from FW.

  10. Microbial monitoring by molecular tools of a two-phase anaerobic bioreactor treating fruit and vegetable wastes.

    Science.gov (United States)

    Bouallagui, H; Torrijos, M; Godon, J J; Moletta, R; Cheikh, R Ben; Touhami, Y; Delgenes, J P; Hamdi, M

    2004-05-01

    Microbial consortia in a two-phase, anaerobic bioreactor using a mixture of fruit and vegetable wastes were established. Bacterial and archaeal communities obtained by a culture-independent approach based on single strand conformation polymorphism analysis of total 16S rDNA showed the adaptation of the microflora to the process parameters. Throughout the 90 d of the study, the species composition of the bacterial community changed significantly. Bacterial 16S rDNA showed at least 7 different major species with a very prominent one corresponding to a Megasphaera elsdenii whereas bacterial 16S rDNA of a methanization bioreactor showed 10 different major species. After two weeks, Prevotella ruminicola became major and its dominance increased continuously until day 50. After an acid shock at pH 5, the 16S rDNA archaeal patterns in the acidogenic reactor showed two major prominent species corresponding to Methanosphaera stadtmanii and Methanobrevibacter wolinii, a hydrogenotrophic bacterium.

  11. Dry anaerobic digestion of rejects from pre-treated food waste; Torroetning av rejekt fraan foerbehandling av matavfall

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, Irene [NSR, Helsingborg (Sweden); Murto, Marika; Bjoernsson, Lovisa [Bioteknik, LTH, Lund (Sweden); Rosqvist, Haakan [Rosqvist Resurs, Klaagerup (Sweden)

    2011-11-15

    When the organic fraction of source separated municipal solid waste is digested anaerobically in a continuously stirred tank reactor there is a need for a pretreatment to make the waste pumpable and remove contaminants. In one type of pretreatment the material passes through a screw press which separates waste in a liquid fraction and a dry fraction (the reject). At NSR this technique is used and at present the reject is incinerated. A previous study has shown that about 30 % of the methane potential of the incoming organic waste can be found in the reject. The aim of the present project was to investigate the possibilities of realizing the methane potential through batch wise dry anaerobic digestion followed by composting as an alternative to incineration. In the technique used in the present project the material was digested in an anaerobic leach-bed with recirculation of leachate over the bed. It is important that the material is sufficiently porous to let the leachate spread evenly through the leach-bed. Treatment of reject and a mixture of reject and structural material were tested to investigate if the addition of structural material had an effect on the porosity. The flow of liquid through a leach-bed of reject and one of reject mixed with structural material was studied using LiBr as tracer. The digestate from the dry digestion process was composted, and the resulting compost was evaluated. The odor from the digestate, the active compost and the compost product was measured by analyzing the odor in the air of the porous space in heaps of the different materials. This was used to evaluate the risk of odor problems. The dry digestion and the tracer experiment both showed that mixing the reject with structural material had a positive effect on the flow of liquid through the material and the digestion process. Addition of structural material to the reject was needed in order to achieve an efficient digestion process. Using tracers proved to be a useful way of

  12. A new approach to the kinetic study of anaerobic degradation of the organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, Franco; Traverso, P.G.; Fazzini, Guido (Venice Univ. (IT). Dip. Scienze Ambientali); Alvarez, J.M. (Barcelona Univ. (ES). Dip. d' Enginyeria Quimica i Metallurgia); Medici, Franco (L' Aquila Univ. (IT). Dip. di Chimica Ingegneria Chimica e Materiali)

    1990-01-01

    The kinetic models proposed by Monod, Chen and Hashimoto and Singh as well as those of a first order and diffusional type have been tested for fit as mathematical descriptions to describe substrate utilization during anaerobic digestion of the organic fraction of source sorted municipal solid waste. A new model, described as step diffusional is proposed and the results obtained with it are compared with those obtained using previously published models. The new model is found to show a better fit to the experimental result than those obtained with other models. The new model takes into account simple qualitative and quantitative chemical characteristics of the substrate to be digested. Although this new model is more complex than some others since it involves four kinetic constants, conceptually it is simple enough to find practical applications. (author).

  13. Starting-up an anaerobic hybrid filter for the fermentation of waste water from food industry

    Energy Technology Data Exchange (ETDEWEB)

    Di Berardino, S. [Instituto Nacional de Engenharia e Tecnologia Industrial, Lisboa (Portugal); Bersi, R. [Istituto di Ingegneria Chimica e di Processo `G.B. Bonino`, Univ. di Genova (Italy); Converti, A. [Istituto di Ingegneria Chimica e di Processo `G.B. Bonino`, Univ. di Genova (Italy); Rovatti, M. [Istituto di Ingegneria Chimica e di Processo `G.B. Bonino`, Univ. di Genova (Italy)

    1997-01-01

    The wastewater from a food processing factory, characterised by fluctuations of flow rate, organic strength, and pH, were originally treated by a traditional suspended-biomass digester working at about 25 C. In order to improve the digester efficiency, either in terms of degradation ability or biogas production yield, a set of tests has been carried out on laboratory scale, whose results indicated the way to correctly transform it into an anaerobic hybrid filter. The unacceptable conversion yield of organic substances into biogas observed in the original system has been improved by the presence of the filling medium, due to a marked increase in biomass retention time. The start-up of anaerobic digestion has been studied in this reactor at two different temperatures (25 and 30 C), in order to evaluate the possible advantage of heating the system, simulating continuous variations in feed strength, pH, and composition. (orig.). With 7 figs., 2 tabs.

  14. Biogas production improvement and C/N control by natural clinoptilolite addition into anaerobic co-digestion of Phragmites australis, feces and kitchen waste.

    Science.gov (United States)

    Wang, Xiaowei; Zhang, Lieyu; Xi, Beidou; Sun, Wenjun; Xia, Xunfeng; Zhu, Chaowei; He, Xiaosong; Li, Mingxiao; Yang, Tianxue; Wang, Pengfei; Zhang, Zhonglei

    2015-03-01

    Anaerobic co-digestion (A co-D) performance of Phragmites australis, feces and kitchen waste with addition of clinoptilolite (one main kind of zeolite) was investigated to evaluate the improvement of biogas/methane production and internal mechanism of nitrogen and organics control. A better biogas/methane production was observed by 10% clinoptilolite (v/v) than bentonite and diatomite, with the shortest lag phase of 0.070d(-1), the max rate of 15.89L/(kgVSday) and ultimate biogas production of 308.2L/kgVS as the modified Gompertz equation predicted. Accordingly, the content of methane in the biogas was increased from 44.10% to 65.30%. Furthermore, the clinoptilolite inhibited the acidification of digestion liquid (optimum pH 7.0-7.5) and enhanced the VFAs (acetic acid, propionic acid and butyric acid) destruction. Moreover, 10% of clinoptilolite optimally enhanced the microbial utilization of Ca(2+)/Mg(2+), controlled the C/N ratio, and improved the biogas production as well as NH3-N/NO3-N inhibition efficiency.

  15. Effect of ultrasonic pre-treatment on biogas yield and specific energy in anaerobic digestion of fruit and vegetable wholesale market wastes

    Directory of Open Access Journals (Sweden)

    Reyhaneh Zeynali

    2017-11-01

    Full Text Available Ultrasonic pre-treatment has been considered as an environmentally friendly process for enhancing the biodegradability of organic matter in anaerobic digestion. However the consumed energy during the pre-treatment is a matter of challenge especially where energy generation is the main purpose of a biogas plant. The aim of the present work was to study the efficiency of ultrasonic pre-treatment in enhancement of biogas production from fruits and vegetable wholesale market waste. Three sonication times (9, 18, 27 min operating at 20 kHz and amplitude of 80 μm were used on the substrate. The highest methane yield was obtained at 18 min sonication (2380 kJ kg−1 total solids while longer exposure to sonication led to lower methane yield. This amount of biogas was obtained in 12 d of batch time. The energy content of the biogas obtained from this reactor was two times of the input energy for sonication.

  16. Effects of cycle-frequency and temperature on the performance of anaerobic sequencing batch reactors (ASBRs) treating swine waste.

    Science.gov (United States)

    Ndegwa, P M; Hamilton, D W; Lalman, J A; Cumba, H J

    2008-04-01

    Anaerobic digestion of animal waste is a technically viable process for the abatement of adverse environmental impacts caused by animal wastes; however, widespread acceptance has been plagued by poor economics. This situation is dismal if the technology is adapted for treating low strength animal slurries because of large digester-volume requirements and a corresponding high energy input. A possible technology to address these constraints is the anaerobic sequencing batch reactor (ASBR). The ASBR technology has demonstrated remarkable potential to improve the economics of treating dilute animal waste effluents. This paper presents preliminary data on the effects of temperature and frequency-cycle on the operation of an ASBR at a fixed hydraulic retention time (HRT). The results suggest that within the parameter range under consideration, temperature did not affect the biogas yield significantly, however, higher cycle-frequency had a negative effect. The biogas quality (%CH(4)) was not significantly affected by temperature nor by the cycle-frequency. The operating principle of the ASBR follows four phases: feed, react, settle, and decant in a cyclic mode. To improve the biogas production in an ASBR, one long react-phase was preferable compared to three shorter react-phases. Treatment of dilute manure slurries in an ASBR at 20 degrees C was more effective than at 35 degrees C; similarly more bio-stable effluents were obtained at low cycle-frequency. The treatment of dilute swine slurries in an ASBR at the lower temperature (20 degrees C) and lower cycle-frequency is, therefore, recommended for the bio-stabilization of dilute swine wastewaters. The results also indicate that significantly higher VFA degradation occurred at 20 degrees C than at 35 degrees C, suggesting that the treatment of dilute swine slurries in ASBRs for odor control might be more favorable at the lower than at the higher temperatures examined in this study. Volatile fatty acid reduction at the two

  17. Reviewing the anaerobic digestion and co-digestion process of food waste from the perspectives on biogas production performance and environmental impacts.

    Science.gov (United States)

    Chiu, Sam L H; Lo, Irene M C

    2016-12-01

    In this paper, factors that affect biogas production in the anaerobic digestion (AD) and anaerobic co-digestion (coAD) processes of food waste are reviewed with the aim to improve biogas production performance. These factors include the composition of substrates in food waste coAD as well as pre-treatment methods and anaerobic reactor system designs in both food waste AD and coAD. Due to the characteristics of the substrates used, the biogas production performance varies as different effects are exhibited on nutrient balance, inhibitory substance dilution, and trace metal element supplement. Various types of pre-treatment methods such as mechanical, chemical, thermal, and biological methods are discussed to improve the rate-limiting hydrolytic step in the digestion processes. The operation parameters of a reactor system are also reviewed with consideration of the characteristics of the substrates. Since the environmental awareness and concerns for waste management systems have been increasing, this paper also addresses possible environmental impacts of AD and coAD in food waste treatment and recommends feasible methods to reduce the impacts. In addition, uncertainties in the life cycle assessment (LCA) studies are also discussed.

  18. Effectiveness of phosphate removal during anaerobic digestion of waste activated sludge by dosing iron(III).

    Science.gov (United States)

    Cheng, Xiang; Wang, Jue; Chen, Bing; Wang, Yu; Liu, Jiaqi; Liu, Lubo

    2017-05-15

    Phosphate-Fe(II) precipitation induced by Fe(III) reduction during the anaerobic digestion of excess activated sludge was investigated for the removal of phosphorus and its possible recovery. The experiments were conducted with three Fe(III) sources at 35 °C and 55 °C. The results show that ferrihydrite-Fe(III) was effectively reduced during the anaerobic sludge digestion by 63% and 96% under mesophilic and thermophilic conditions, respectively. Whereas FeCl3-Fe(III) was only mesophilically reducible and the reduction of hematite-Fe(III) was unnoticeable at either temperature. Efficient precipitation of vivianite was not observed although high saturation index values, e.g., >14 (activity reduction not considered), had been reached. This reveals the complexity of vivianite precipitation in anaerobic digestion systems; for example, Fe(II) complexation and organic interference could not be ignored. With ferrihydrite amendments at a Fe/TP of 1.5, methane production from sludge digestion was reduced by 35.1% at 35 °C, and was unaffected when the digestion temperature went up to 55 °C. But, acidic FeCl3 severely inhibited the methane production and consequently the sludge biomass degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Study of the inhibitory phenomena during the anaerobic digestion of sugar cane mill mud waste; Estudio del fenomeno de inhibicion durante la digestion anaerobia de cachaza

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, M.; Sanchez, E.; Montalvo, S.; Escobedo, R. [Centro Nacional de Investigaciones Cientificas . Ciudad de la Habana. Cuba (Cuba); Garcia-Morales, J. L. [Universidad de Cadiz (Spain)

    2001-07-01

    Sugar cane mill mud waste is one of the effluents obtained during the process of sugar production, specifically, in the stage of clarification and filtration of the cane's juice. This effluent can be treated anaerobically in order to reduce its contamination and use the biogas like a resource. This work shows the study of the inhibition originated along the anaerobic digestion of sugar mill mud waste and evaluates the influence of waste pre-treatment on this process. Th inhibitory effect was verified and quantified. The quantification was carried out applying the Levenspiel model, using the evolution of the constant kinetic of the apparent rate (K{sub {omicron}}). Author 5 refs.

  20. Microbial population dynamics in urban organic waste anaerobic co-digestion with mixed sludge during a change in feedstock composition and different hydraulic retention times

    DEFF Research Database (Denmark)

    Fitamo, Temesgen Mathewos; Treu, Laura; Boldrin, Alessio

    2017-01-01

    organic polymers was found to be the most active process, performed by members of S1 (Thermotogales), Thermonema and Lactobacillus in a reactor fed with a high share of food waste. Conversely, Thermacetogenium, Anaerobaculum, Ruminococcaceae, Porphyromonadaceae and the lignocellulosic-degrading......Microbial communities play an essential role in the biochemical pathways of anaerobic digestion processes. The correlations between microorganisms' relative abundance and anaerobic digestion process parameters were investigated, by considering the effect of different feedstock compositions...... and hydraulic retention times (HRTs). Shifts in microbial diversity and changes in microbial community richness were observed by changing feedstock composition from mono-digestion of mixed sludge to co-digestion of food waste, grass clippings and garden waste with mixed sludge at HRT of 30, 20, 15 and 10 days...

  1. Enhancing the anaerobic digestion of corn stalks using composite microbial pretreatment.

    Science.gov (United States)

    Yuan, Xufeng; Li, Peipei; Wang, Hui; Wang, Xiaofen; Cheng, Xu; Cui, Zongjun

    2011-07-01

    A composite microbial system (XDC-2) was used to pretreat and hydrolyze corn stalk to enhance anaerobic digestion. The results of pretreatment indicated that sCOD concentrations of hydrolysate were highest (8,233 mg/l) at the fifth day. XDC-2 efficiently degraded the corn stalk by nearly 45%, decreasing the cellulose content by 22.7% and the hemicellulose content by 74.1%. Total levels of volatile products peaked on the fifth day. The six major compounds present were ethanol (0.29 g/l), acetic acid (0.55 g/l), 1,2-ethanediol (0.49 g/l), propionic acid (0.15 g/l), butyric acid (0.22 g/l), and glycerine (2.48 g/l). The results of anaerobic digestion showed that corn stalks treated by XDC-2 produced 68.3% more total biogas and 87.9% more total methane than untreated controls. The technical digestion time for the treated corn stalks was 35.7% shorter than without treatment. The composite microbial system pretreatment could be a cost-effective and environmentally friendly microbial method for efficient biological conversion of corn stalk into bioenergy.

  2. Vertical profiles of community abundance and diversity of anaerobic methanotrophic archaea (ANME) and bacteria in a simple waste landfill in north China.

    Science.gov (United States)

    Dong, Jun; Ding, Linjie; Wang, Xu; Chi, Zifang; Lei, Jiansen

    2015-03-01

    Anaerobic methane oxidation (AMO) is considered to be an important sink of CH4 in habitats as marine sediments. But, few studies focused on AMO in landfills which may be an important sink of CH4 derived from waste fermentation. To show evidence of AMO and to uncover function anaerobic methanotroph (ANME) community in landfill, different age waste samples were collected in Jinqianpu landfill located in north China. Through high-throughput sequencing, Methanomicrobiales and Methanosarcinales archaea associated with ANME and reverse methanogenic archaea of Methanosarcina and Methanobacterium were detected. Sulfate-reducing bacteria (SRB) (Desulfobulbus and Desulfococcus) which could couple with ANME-conducting AMO were also found. But, the community structure of ANME had no significant difference with depths. From the results of investigation, we can come to a conclusion that sulfate-dependent anaerobic methane oxidation (SR-DAMO) would be the dominant AMO process in the landfill, while iron-dependent anaerobic methane oxidation (M/IR-DAMO) process was weak though concentration of ferric iron was large in the landfill. Denitrification-dependent anaerobic methane oxidation (NR-DAMO) was negative because of lack of nitrate and relevant function microorganisms in the landfill. Results also indicate that CH4 mitigation would have higher potential by increasing electron acceptor contents and promoting the growth of relevant function microorganisms.

  3. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling

    DEFF Research Database (Denmark)

    Fitamo, Temesgen Mathewos; Boldrin, Alessio; Dorini, G.

    2016-01-01

    strategies for controlling and optimising the co-digestion process. The model parameters were maintained in the same way as the original dynamic bioconversion model, albeit with minor adjustments, to simulate the co-digestion of food and garden waste with mixed sludge from a wastewater treatment plant...... scenario analysis demonstrated that increasing the amount of mixed sludge in the co-substrate had a marginal effect on the reactor performance. In contrast, increasing the amount of food waste and garden waste resulted in improved performance....

  4. Dual purpose system that treats anaerobic effluents from pig waste and produce Neochloris oleoabundans as lipid rich biomass.

    Science.gov (United States)

    Olguín, Eugenia J; Castillo, Omar S; Mendoza, Anilú; Tapia, Karla; González-Portela, Ricardo E; Hernández-Landa, Víctor J

    2015-05-25

    Dual purpose systems that treat wastewater and produce lipid rich microalgae biomass have been indicated as an option with great potential for production of biodiesel at a competitive cost. The aim of the present work was to develop a dual purpose system for the treatment of the anaerobic effluents from pig waste utilizing Neochloris oleoabundans and to evaluate its growth, lipid content and lipid profile of the harvested biomass and the removal of nutrients from the media. Cultures of N. oleoabundans were established in 4 L flat plate photobioreactors using diluted effluents from two different types of anaerobic filters, one packed with ceramic material (D1) and another one packed with volcanic gravel (D2). Maximum biomass concentration in D1 was 0.63 g L(-1) which was significantly higher than the one found in D2 (0.55 g L(-1)). Cultures were very efficient at nutrient removal: 98% for NNH4(+) and 98% for PO4(3-). Regarding total lipid content, diluted eflluents from D2 promoted a biomass containing 27.4% (dry weight) and D1 a biomass containing 22.4% (dry weight). Maximum lipid productivity was also higher in D2 compared to D1 (6.27±0.62 mg L(-1) d(-1) vs. 5.12±0.12 mg L(-1) d(-1)). Concerning the FAMEs profile in diluted effluents, the most abundant one was C18:1, followed by C18:2 and C16:0. The profile in D2 contained less C18:3 (linolenic acid) than the one in D1 (4.37% vs. 5.55%). In conclusion, this is the first report demonstrating that cultures of N. oleoabundans treating anaerobic effluents from pig waste are very efficient at nutrient removal and a biomass rich in lipids can be recovered. The maximum total lipid content and the most convenient FAMEs profile were obtained using effluents from a digester packed with volcanic gravel. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Inhibition of residual n-hexane in anaerobic digestion of lipid-extracted microalgal wastes and microbial community shift.

    Science.gov (United States)

    Yun, Yeo-Myeong; Shin, Hang-Sik; Lee, Chang-Kyu; Oh, You-Kwan; Kim, Hyun-Woo

    2016-04-01

    Converting lipid-extracted microalgal wastes to methane (CH4) via anaerobic digestion (AD) has the potential to make microalgae-based biodiesel platform more sustainable. However, it is apparent that remaining n-hexane (C6H14) from lipid extraction could inhibit metabolic pathway of methanogens. To test an inhibitory influence of residual n-hexane, this study conducted a series of batch AD by mixing lipid-extracted Chlorella vulgaris with a wide range of n-hexane concentration (∼10 g chemical oxygen demand (COD)/L). Experimental results show that the inhibition of n-hexane on CH4 yield was negligible up to 2 g COD/L and inhibition to methanogenesis became significant when it was higher than 4 g COD/L based on quantitative mass balance. Inhibition threshold was about 4 g COD/L of n-hexane. Analytical result of microbial community profile revealed that dominance of alkane-degrading sulfate-reducing bacteria (SRB) and syntrophic bacteria increased, while that of methanogens sharply dropped as n-hexane concentration increased. These findings offer a useful guideline of threshold n-hexane concentration and microbial community shift for the AD of lipid-extracted microalgal wastes.

  6. Anaerobic co-digestion of vegetable waste and swine wastewater in high-rate horizontal reactors with fixed bed.

    Science.gov (United States)

    Mazareli, Raissa Cristina da Silva; Duda, Rose Maria; Leite, Valderi Duarte; Oliveira, Roberto Alves de

    2016-06-01

    Considering the high waste generation that comes from agriculture and livestock farming, as well as the demand for natural gas, it is necessary to develop sustainable technologies which can reduce environmental impact. There is no available literature on the use of high-rate horizontal anaerobic reactors with fixed bed (HARFB) and continuous feed for the co-digestion of vegetable wastes (VW) and swine wastewater (SW). The aim of this work was to evaluate the reactor performance in terms of methane production, organic matter consumption, and removal of total and thermotolerant coliforms under different proportions of SW and VW, and organic loading rates (OLR) of 4.0, 5.2 and 11.0g COD (Ld)(-)(1). The mixture of SW and VW in the proportions of 90:10, 80:20 and 70:30 (SW:VW) with those OLRs provided great buffering capacity, with partial alkalinity reaching 3552mgL(-1), thereby avoiding the inhibition of methane production by volatile fatty acids produced during the fermentation process. Higher proportions of VW and higher OLR improved volumetric methane production with a maximum value of 1.08LCH4 (Ld)(-)(1), organic matter removal rates up to 98% and total and thermotolerant coliform removal rates of 99% were also observed.

  7. Anaerobic digestion of waste biomass from the production of L-cystine in suspended-growth bioreactors.

    Science.gov (United States)

    Chávez-Fuentes, Juan José; Hutňan, Miroslav; Bodík, Igor; Zakhar, Ronald; Czölderová, Marianna

    2015-01-01

    Waste biomass from the industrial production of the amino acid L-cystine contains above-average concentrations of organic pollutants and significant concentrations of nitrogen and sulfur. The specific biogas production (SBP) of waste biomass was monitored in parallel suspended-growth laboratory anaerobic bioreactors. After severe inhibition was observed, three different procedures were applied to inhibited reactor sludge to counter-attack the inhibitory effects of sulfides, respectively hydrogen sulfide: micro-aeration, dilution with water and precipitation by ferrous iron cations. The performance of bioreactors was weekly monitored. Organic loading rates (as chemical oxygen demand, COD) ranged from 1.07 to 1.97 g L(-1) d(-1). At the end of the experimentation, SBP averaged 217, 300 and 320 l kg(-1) COD with a methane content of 21%, 52% and 54%; specific sludge production averaged 133, 111 and 400 g total solids kg(-1) COD, and inhibition was 49%, 27% and 25%; for the applied procedures of micro-aeration, dilution and precipitation respectively.

  8. Evaluation of In-situ Sludge Reduction and Enhanced Nutrient Removal in an Integrated Repeatedly Coupling Aerobic and Anaerobic and Oxic-setting-anaerobic System

    Institute of Scientific and Technical Information of China (English)

    Shanshan Yang; Wanqian Guo; Qinglian Wu; Haichao Luo; Simai Peng; Heshan Zheng; Xiaochi Feng; Nanqi Ren∗

    2015-01-01

    Aiming to achieve simultaneous good performances of in⁃situ sludge reduction and effluent quality, an integrated repeatedly coupling aerobic and anaerobic and oxic⁃setting⁃anaerobic system ( rCAA+OSA ) is developed to reduce sludge production and enhance nutrient removal. Considering the mechanism of in⁃situ sludge reduction in this rCAA+OSA system, the combined effect of energy uncoupling metabolism and sludge cryptic growth maybe attributed to the higher reduction of biomass. Results show that the maximal sludge reduction in this rCAA+OSA system is obtained when the hydraulic retention time ( HRT ) is controlled at 6�5 h, which an increase in 16�67% reduction in excess sludge is achieved compared with OSA system ( HRT of 6�5 h) . When compared the performances of effluent qualities, the enhanced nutrient removal efficiencies also can be observed in this rCAA+OSA system. Three⁃dimensional excitation emission matrix ( 3D⁃EEM ) fluorescence spectroscopy is applied to characterize the effluent organic matters ( EfOM) under different HRTs in the OSA and the rCAA+OSA systems. Analyses of 3D⁃EEM spectra show that more refractory humic⁃like and fulvic⁃like components are observed in the effluent of the OSA system. On the basis of these results, simultaneous enhanced in⁃situ sludge reduction and improved nutrient removal can be obtained in the rCAA+OSA systems.

  9. Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Uma Rani, R.; Adish Kumar, S. [Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli 627 007, Tamil Nadu (India); Kaliappan, S. [Department of Civil Engineering, Ponjesly College of Engineering, Nagercoil 629 003, Tamil Nadu (India); Yeom, IckTae [Department of Civil and Environmental Engineering, Sungkyunkwan University (Korea, Republic of); Rajesh Banu, J., E-mail: rajeshces@gmail.com [Department of Civil Engineering, Regional Centre of Anna University, Tirunelveli 627 007, Tamil Nadu (India)

    2013-05-15

    Highlights: ► Microwave pretreatment of dairy WAS was studied. ► MW pretreatment at 70% intensity for 12 min, COD solubilization was 18.6%. ► Biogas production and SS reduction was 35% and 14% higher than control. ► In digester at 15 days SRT with medium OLR, SS and VS reduction was 67% and 64%. ► Biogas and methane production was 57% and 49% higher than control, in digesters. - Abstract: Microwave (MW) irradiation is one of the new and possible methods used for pretreating the sludge. Following its use in different fields, this MW irradiation method has proved to be more appropriate in the field of environmental research. In this paper, we focused on the effects of MW irradiation at different intensities on solubilization, biodegradation and anaerobic digestion of sludge from the dairy sludge. The changes in the soluble fractions of the organic matter, the biogas yield, the methane content in the biogas were used as control parameters for evaluating the efficiency of the MW pretreatment. Additionally, the energetic efficiency was also examined. In terms of an energetic aspect, the most economical pretreatment of sludge was at 70% intensity for 12 min irradiation time. At this, COD solubilization, SS reduction and biogas production were found to be 18.6%, 14% and 35% higher than the control, respectively. Not only the increase in biogas production was investigated, excluding protein and carbohydrate hydrolysis was also performed successfully by this microwave pretreatment even at low irradiation energy input. Also, experiments were carried out in semi continuous anaerobic digesters, with 3.5 L working volume. Combining microwave pretreatment with anaerobic digestion led to 67%, 64% and 57% of SS reduction, VS reduction and biogas production higher than the control, respectively.

  10. Mesophilic batch anaerobic co-digestion of fruit-juice industrial waste and municipal waste sludge: process and cost-benefit analysis.

    Science.gov (United States)

    Hosseini Koupaie, E; Barrantes Leiva, M; Eskicioglu, C; Dutil, C

    2014-01-01

    The feasibility of anaerobic co-digestion of two juice-based beverage industrial wastes, screen cake (SC) and thickened waste activated sludge (TWAS), along with municipal sludge cake (MC) was investigated. Experiments were conducted in twenty mesophilic batch 160 ml serum bottles with no inhibition occurred. The statistical analysis proved that the substrate type had statistically significant effect on both ultimate biogas and methane yields (P=0.0003<0.05). The maximum and minimum ultimate cumulative methane yields were 890.90 and 308.34 mL/g-VSremoved from the digesters containing only TWAS and SC as substrate. First-order reaction model well described VS utilization in all digesters. The first 2-day and 10-day specific biodegradation rate constants were statistically higher in the digesters containing SC (P=0.004<0.05) and MC (P=0.0005<0.05), respectively. The cost-benefit analysis showed that the capital, operating and total costs can be decreased by 21.5%, 29.8% and 27.6%, respectively using a co-digester rather than two separate digesters.

  11. Effects of temperature and organic loading rate on the performance and microbial community of anaerobic co-digestion of waste activated sludge and food waste.

    Science.gov (United States)

    Gou, Chengliu; Yang, Zhaohui; Huang, Jing; Wang, Huiling; Xu, Haiyin; Wang, Like

    2014-06-01

    Anaerobic co-digestion of waste activated sludge and food waste was investigated semi-continuously using continuously stirred tank reactors. Results showed that the performance of co-digestion system was distinctly influenced by temperature and organic loading rate (OLR) in terms of gas production rate (GPR), methane yield, volatile solids (VS) removal efficiency and the system stability. The highest GPR at 55 °C was 1.6 and 1.3 times higher than that at 35 and 45 °C with the OLR of 1 g VSL(-1)d(-1), and the corresponding average CH₄ yields were 0.40, 0.26 and 0.30 L CH₄ g(-1)VSadded, respectively. The thermophilic system exhibited the best load bearing capacity at extremely high OLR of 7 g VSL(-1)d(-1), while the mesophilic system showed the best process stability at low OLRs (< 5 g VSL(-1)d(-1)). Temperature had a more remarkable effect on the richness and diversity of microbial populations than the OLR.

  12. Performances of anaerobic co-digestion of fruit & vegetable waste (FVW) and food waste (FW): single-phase vs. two-phase.

    Science.gov (United States)

    Shen, Fei; Yuan, Hairong; Pang, Yunzhi; Chen, Shulin; Zhu, Baoning; Zou, Dexun; Liu, Yanping; Ma, Jingwei; Yu, Liang; Li, Xiujin

    2013-09-01

    The co-digestion of fruit & vegetable waste (FVW) and food waste (FW) was performed at various organic loading ratios (OLRs) in single-phase and two-phase system, respectively. The results showed that the ethanol-type fermentation dominated in both digestion processes when OLR was at low levels (2.0 g(VS) L(-1) d(-1)), which could cause unstable anaerobic digestion. Single-phase digestion was better than two-phase digestion in term of 4.1% increase in CH4 production at lower OLRs (two-phase digestion achieved higher CH4 production of 0.351-0.455 L(g VS)(-1) d(-1), which were 7.0-15.8% more than that of single-phase. Additionally, two-phase digestion presented more stable operation, and higher OLR treatment capacity. Furthermore, comparison of these two systems with bioenergy recovery revealed that two-phase system overall presented higher bioenergy yield than single-phase.

  13. Microbial Anaerobic Digestion (Bio-Digesters as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    Directory of Open Access Journals (Sweden)

    Golden Makaka

    2013-09-01

    Full Text Available With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  14. Microbial Anaerobic Digestion (Bio-Digesters) as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    Science.gov (United States)

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

    2013-01-01

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications. PMID:24048207

  15. Microbial anaerobic digestion (bio-digesters) as an approach to the decontamination of animal wastes in pollution control and the generation of renewable energy.

    Science.gov (United States)

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2013-09-17

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  16. Anaerobic Co-digestion for Enhanced Renewable Energy and Green House Gas Emission Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Navaratnam, Navaneethan; Zitomer, Daniel

    2012-05-01

    The need to develop renewable energy is important for replacing fossil fuel, which is limited in quantity and also tends to increase in price over time. The addition of high strength organic wastes in municipal anaerobic digesters is growing and tends to increase renewable energy production. In addition, conversion of wastes to energy significantly reduces uncontrolled greenhouse gas emissions. Co-digestion of municipal sludge with any combination of wastes can result in synergistic, antagonistic or neutral outcomes. The objectives of this study were to identify potential co-digestates, determine synergistic, antagonistic and neutral effects, determine economic benefits, quantify performance of bench scale co-digesters, identify influence of co-digestion on microbial communities and implement appropriate co-digestion, if warranted, after full-scale testing. A market study was used to identify promising co-digestates. Most promising wastes were determined by biochemical methane potential (BMP) and other testing followed by a simple economic analysis. Performance was investigated using bench-scale digesters receiving synthetic primary sludge with and without co-digestates. Denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction (qPCR) analyses were performed on the gene encoding the α subunit of methyl coenzyme M reductase (mcrA) to compare methanogen communities among the digesters. One significant band contributing to the greatest difference in banding patterns was excised, cloned, amplified and sequenced. Full- scale co-digestion was conducted using the most promising co-digestate at South Shore Wastewater Reclamation Facility (Oak Creek, WI). Over 80 wastes were identified from 54 facilities within 160 km of an existing municipal digester. A simple economic comparison identified the greatest benefits for seven co-digestates. Methane production rates of two co- digester systems increased by 105% and 66% in comparison to a control

  17. Life Cycle Assessment of pretreatment technologies for anaerobic digestion of source-separated organic household waste

    DEFF Research Database (Denmark)

    Naroznova, Irina; Møller, Jacob; Scheutz, Charlotte

    2013-01-01

    traditional pretreatment method using a screw press. The inventory of the technologies was constructed including the mass balance, amount of biogas produced, nutrient recovery rates, and produced biomass quality. The technologies were modelled in the LCA-model EASETECH and the potential environmental impacts......The environmental performance of two pretreatment technologies for source-separated organic waste was compared using life cycle assessment (LCA). An innovative pulping process where source-separated organic waste is pulped with cold water forming a volatile solid rich biopulp was compared to a more...... including a number of non-toxic and toxic impact categories were assessed. No big difference in the overall performance of the two technologies was observed. The difference for the separate life cycle steps was, however, more pronounced. More efficient material transfer in the scenario with waste pulping...

  18. Conversion of organic carbon in the decomposable organic wastes in anaerobic lysimeters under different temperatures

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The quantitative fractions of conversion of organic carbon in the decomposable organic wastes with initial moisture of 70% sorted from municipal solid wastes(MSW) in lysimeters into biogas, leachate and solid residue were characterized, under temperatures of 25, 30 and 41℃, respectively, and circulation of leachate generated within the lysimeters. It is found that 27% of organic carbon in the wastes are conversed into gases, 0.8% into leachate, and the other 72% remained in the decomposable solid residues, after 180 days' degradation at 41℃. Higher temperature will lead to more rapid degradation and result to higher conversion of the organic carbon to biogas and lower to both solid residues and leachate, while the pollutant concentrations in leachate will be lower at a higher temperature and the values of COD are quite consistent with TOC.

  19. Succession of microbial community and enhanced mechanism of a ZVI-based anaerobic granular sludge process treating chloronitrobenzenes wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang, E-mail: felix79cn@hotmail.com [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058 (China); Jin, Jie [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Lin, Haizhuan [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Wenzhou Environmental Protection Design Scientific Institute, Wenzhou 325000 (China); Gao, Kaituo [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Xu, Xiangyang, E-mail: xuxy@zju.edu.cn [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058 (China)

    2015-03-21

    Highlights: • The combined ZVI–UASB process was established for the degradation of chloronitrobenzenes. • There were the better shock resistance and buffering capacity for anaerobic acidification in the combined process. • Novel ZVI-based anaerobic granular sludge (ZVI–AGS) was successfully developed. • Adaptive shift of microbial community was significant in ZVI-based anaerobic granular sludge system. - Abstract: The combined zero-valent iron (ZVI) and upflow anaerobic sludge blanket (UASB) process is established for the treatment of chloronitrobenzenes (ClNBs) wastewater, and the succession of microbial community and its enhanced mechanism are investigated in the study. Results showed that compared with the control UASB (R1), the stable COD removal, ClNBs transformation, and dechlorination occurred in the combined system (R2) when operated at influent COD and 3,4-Dichloronitrobenzene (3,4-DClNB) loading rates of 4200–7700 g m{sup −3} d{sup −1} and 6.0–70.0 g m{sup −3} d{sup −1}, and R2 had the better shock resistance and buffering capacity for the anaerobic acidification. The dechlorination for the intermediate products of p-chloroanaline (p-ClAn) to analine (AN) occurred in R2 reactor after 45 days, whereas it did not occur in R1 after a long-term operation. The novel ZVI-based anaerobic granular sludge (ZVI–AGS) was successfully developed in the combined system, and higher microbial activities including ClNB transformation and H{sub 2}/CH{sub 4} production were achieved simultaneously. The dominant bacteria were closely related to the groups of Megasphaera, Chloroflexi, and Clostridium, and the majority of archaea were correlated with the groups of Methanosarcinalesarchaeon, Methanosaetaconcilii, and Methanothrixsoehngenii, which are capable of reductively dechlorinating PCB, HCB, and TCE in anaerobic niche and EPS secretion.

  20. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9...

  1. Biogenic hydrogen conversion of de-oiled jatropha waste via anaerobic sequencing batch reactor operation: process performance, microbial insights, and CO2 reduction efficiency.

    Science.gov (United States)

    Kumar, Gopalakrishnan; Lin, Chiu-Yue

    2014-01-01

    We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L ∗ d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55 °C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L ∗ d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30 °C, and pH 7.0. PCR-DGGE analysis revealed that combination of cellulolytic and fermentative bacteria were present in the hydrogen producing ASBR.

  2. Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, and CO2 Reduction Efficiency

    Directory of Open Access Journals (Sweden)

    Gopalakrishnan Kumar

    2014-01-01

    Full Text Available We report the semicontinuous, direct (anaerobic sequencing batch reactor operation hydrogen fermentation of de-oiled jatropha waste (DJW. The effect of hydraulic retention time (HRT was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L*d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d with a DJW concentration of 200 g/L, temperature 55°C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L*d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30°C, and pH 7.0. PCR-DGGE analysis revealed that combination of celluloytic and fermentative bacteria were present in the hydrogen producing ASBR.

  3. Central treatment of different emulsion wastewaters by an integrated process of physicochemically enhanced ultrafiltration and anaerobic-aerobic biofilm reactor.

    Science.gov (United States)

    Zhang, Weijun; Xiao, Ping; Wang, Dongsheng

    2014-05-01

    The feasibility of an integrated process of ultrafiltration (UF) enhanced by combined chemical emulsion breaking with vibratory shear and anaerobic/aerobic biofilm reactor for central treatment of different emulsion wastewaters was investigated. Firstly, it was found that calcium chloride exhibited better performance in oil removal than other inorganic salts. Chemical demulsification pretreatment could efficiently improve oil removal and membrane filtration in emulsion wastewater treatment by VSEP. According to aerobic batch bioassay, UF permeate exhibited good biodegradability and could be further treated with biological process. Additionally, pilot test indicated that anaerobic-aerobic biofilm exhibited an excellent ability against rise in organic loading and overall chemical oxygen demand (COD) removal efficiency of biological system was more than 93% of which 82% corresponded to the anaerobic process and 11% to the aerobic degradation. The final effluent of integrated process could meet the "water quality standards for discharge to municipal sewers" in China.

  4. Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

    Science.gov (United States)

    Cheng, Xi-Yu; Liu, Chun-Zhao

    2012-01-01

    A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%.

  5. Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw

    Institute of Scientific and Technical Information of China (English)

    Chong Wang; Jiane Zuo; Xiaojie Chen; Wei Xing; Linan Xing; Peng Li; Xiangyang Lu

    2014-01-01

    The microbial community structures in an integrated two-phase anaerobic reactor (ITPAR) were investigated by 16S rDNA clone library technology.The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom,with a recirculation connected to the two units.The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw,which showed a very good biogas production and decomposition of cellulosic materials.The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor,with more bacteria community diversities in the acidogenic unit.The methanogens were mostly related with Methanosaeta,Methanosarcina,Methanoculleus,Methanospirillum and Methanobacterium; the predominating genus Methanosaeta,accounting for 40.5%,54.2%,73.6% and 78.7% in four samples from top to bottom,indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit.The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit.The differentiation of methanogenic community composition in two phases,as well as pH values and volatile fatty acid (VFA) concentrations confirmed the phase separation of the ITPAR.Overall,the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens,more diverse communities and stronger syntrophic assodations among microorganisms,which made two phase anaerobic digestion of cellulosic materials more efficient.

  6. Effect of organic loading on the microbiota in a temperature-phased anaerobic digestion (TPAD) system co-digesting dairy manure and waste whey.

    Science.gov (United States)

    Li, Yueh-Fen; Abraham, Christopher; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Yu, Zhongtang

    2015-10-01

    Temperature-phased anaerobic digestion (TPAD) has gained increasing attention because it provides the flexibility to operate digesters under conditions that enhance overall digester performance. However, research on impact of organic overloading rate (OLR) to microbiota of TPAD systems was limited. In this study, we investigated the composition and successions of the microbiota in both the thermophilic and the mesophilic digesters of a laboratory-scale TPAD system co-digesting dairy manure and waste whey before and during organic overloading. The thermophilic and the mesophilic digesters were operated at 50 and 35 °C, respectively, with a hydraulic retention time (HRT) of 10 days for each digester. High OLR (dairy manure with 5 % total solid and waste whey of ≥60.4 g chemical oxygen demand (COD)/l/day) resulted in decrease in pH and in biogas production and accumulation of volatile fatty acids (VFAs) in the thermophilic digester, while the mesophilic digester remained unchanged except a transient increase in biogas production. Both denaturant gradient gel electrophoresis (DGGE) and Illumina sequencing of 16S ribosomal RNA (rRNA) gene amplicons showed dramatic change in microbiota composition and profound successions of both bacterial and methanogenic communities. During the overloading, Thermotogae was replaced by Proteobacteria, while Methanobrevibacter and archaeon classified as WCHD3-02 grew in predominance at the expense of Methanoculleus in the thermophilic digester, whereas Methanosarcina dominated the methanogenic community, while Methanobacterium and Methanobrevibacter became less predominant in the mesophilic digester. Canonical correspondence analysis (CCA) revealed that digester temperature and pH were the most influential environmental factors that explained much of the variations of the microbiota in this TPAD system when it was overloaded.

  7. Rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment.

    Science.gov (United States)

    Liu, Jibao; Yu, Dawei; Zhang, Jian; Yang, Min; Wang, Yawei; Wei, Yuansong; Tong, Juan

    2016-07-01

    The rheological behavior of sludge is of serious concern in anaerobic digestion. This study investigated the rheological properties of sewage sludge during enhanced anaerobic digestion with microwave-H2O2 pretreatment (MW-H2O2). The results showed that MW-H2O2 pretreatment resulted in the improvement of sludge flowability and weakening of its viscoelastic properties. Further positive effects on the rheological properties of digested sludge during anaerobic digestion were observed. The flowability was improved with a low level of apparent viscosity. The decrease of the consistency index and increase of the flow behavior index indicated that the strength of the inner structures and non-Newtonian flow characteristics of digested sludge weakened. Both the storage modulus (G') and loss modulus (G″) decreased, indicating that the viscoelastic behavior became weak. These effects were possibly attributed to the changes of the digested sludge micro-structures, such as extracellular polymeric substances (EPS). This study concluded that anaerobic digestion for treating sewage sludge combined with pretreatment is a more favorable option than single anaerobic digestion from the perspective of rheology.

  8. Energy balance, greenhouse gas emissions, and profitability of thermobarical pretreatment of cattle waste in anaerobic digestion.

    Science.gov (United States)

    Budde, Jörn; Prochnow, Annette; Plöchl, Matthias; Suárez Quiñones, Teresa; Heiermann, Monika

    2016-03-01

    In this study modeled full scale application of thermobarical hydrolysis of less degradable feedstock for biomethanation was assessed in terms of energy balance, greenhouse gas emissions, and economy. Data were provided whether the substitution of maize silage as feedstock for biogas production by pretreated cattle wastes is beneficial in full-scale application or not. A model device for thermobarical treatment has been suggested for and theoretically integrated in a biogas plant. The assessment considered the replacement of maize silage as feedstock with liquid and/or solid cattle waste (feces, litter, and feed residues from animal husbandry of high-performance dairy cattle, dry cows, and heifers). The integration of thermobarical pretreatment is beneficial for raw material with high contents of organic dry matter and ligno-cellulose: Solid cattle waste revealed very short payback times, e.g. 9 months for energy, 3 months for greenhouse gases, and 3 years 3 months for economic amortization, whereas, in contrast, liquid cattle waste did not perform positive replacement effects in this analysis.

  9. Anaerobic Co-Digestion of Mixed Kitchen Wastes and Buffalo Dung

    Directory of Open Access Journals (Sweden)

    Pradip B. Acharya

    2014-12-01

    Full Text Available also generates organic wastes which are generally dumped. On the other hand many people felt shortage of animal dung for biogas production. This study is an attempt to find out the way between these situations by finding the suitability of kitchen wastes addition for biogas production. The experiment was performed in 5 L glass bottles with two treatments i.e. buffalo dung alone and mixture of dung with kitchen wastes. The bottles were filled on daily feeding basis by the feeding material at 5.3% total solids for the experimentation period of 80 days. On first day 12 mL fresh digested biogas slurry from running biogas plant was also added in all the digesters as inoculum. Daily biogas production was measured by water displacement method. Results show that co-digestion of dung and kitchen wastes produces 85.71 to 195.12% higher biogas than dung alone. Overall it produces 2.69% higher total biogas for the experimentation period of 80 days.

  10. The influence of iron concentration on biohydrogen production from organic waste via anaerobic fermentation.

    Science.gov (United States)

    Boni, M R; Sbaffoni, S; Tuccinardi, L

    2014-01-01

    Different micronutrients are essential for bacterial fermentative metabolism. In particular, some metallic ions, like iron, are able to affect the biological H₂production. In this study, batch tests were carried out in stirred reactors to investigate the effects of Fe²⁺ concentration on fermentative H₂production from two different organic fractions of waste: source-separated organic waste (OW) from a composting plant including organic fraction of municipal solid waste and food waste (FW) from a refectory. Iron supplementation at 1000 mg/L caused twofold increment in the cumulative H₂production from OW (922 mL) compared with the control (without iron doping). The highest H₂production (1736 mL) from FW occurred when Fe²⁺ concentration was equal to 50 mg/L. In addition, the process production from OW was modelled through the modified Gompertz equation. For FW, a translated Gompertz equation was used by the authors, because the initial lag-time for H₂production from FW was almost negligible.

  11. Anaerobic digestion of catering wastes: effect of micronutrients and retention time.

    Science.gov (United States)

    Climenhaga, M A; Banks, C J

    2008-01-01

    Source-separated foodwastes collected from a campus catering facility were processed in bench-scale single-stage anaerobic digesters. The feedstock contained a varied mix of fruits, vegetables, meats and fried foods. A constant organic loading rate (OLR) was maintained with differing hydraulic retention times (HRT). Regular addition of trace elements or prolonged retention time allowed stable digestion at high total volatile fatty acid (TVFA) levels. Reactors on HRT of 25, 50, and 100 days with no micronutrient supplementation exhibited methanogenic failure after approximately 40, 100 and 90 days respectively, while duplicate reactors with micronutrient supplementation maintained stable digestion. An extended HRT of 180 days has so far allowed continued digestion (for reactors with and without micronutrient supplementation) at levels of ammonia nitrogen exceeding 5.7 g l(-1) and volatile fatty acid levels exceeding 15 g l(-1), usually considered inhibitory or toxic.

  12. Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process.

    Science.gov (United States)

    Houbron, E; Larrinaga, A; Rustrian, E

    2003-01-01

    This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with a working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g x l(-1) x d(-1) and 0.5 COD g x l(-1) x d(-1). The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g x l(-1) respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD x l(-1) x d(-1) and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD x l(-1), and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH4 and 20% CO2. These results show that a humid coffee "Beneficio" processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH4 m3 x d(-1). This represents an increase in methane production by a factor 3 to 5 compared to a "Beneficio" using anaerobic digestion only for the treatment of its wastewater.

  13. Improved anaerobic digestion of a thermally pretreated mixture of physicochemical sludge; broiler excreta and sugar cane wastes (SCW): Effect on organic matter solubilization, biodegradability and bioenergy production.

    Science.gov (United States)

    Nava-Valente, Noemí; Alvarado-Lassman, Alejandro; Nativitas-Sandoval, Liliana S; Mendez-Contreras, Juan M

    2016-01-01

    Thermal pretreatment effect of a mixture of organic wastes (physicochemical sludge, excreta of broiler chickens and sugarcane wastes (SCW)) in the solubilization and biodegradability organic matter as well as bioenergy production by anaerobic digestion was evaluated. Two different mixtures of physicochemical sludge, excreta of broiler chickens and SCW (70%, 15%, 15% and 60%, 20%, 20% of VS, respectively) were treated at different temperatures (80 °C, 85 °C and 90 °C) and contact time (30, 60 and 90 min). Results indicate that, organic matter solubilization degree increased from 1.14 to 6.56%; subsequently, in the anaerobic digestion process, an increase of 50% in the volatile solids removal and 10% in biogas production was observed, while, retention time decreased from 23 up to 9 days. The results obtained were similar to pilot-scale. In both experimental scales it showed that the synergy produced by the simultaneous anaerobic digestion of different substrates could increase bioenergy production up to 1.3 L bio g(-1) VS removed and 0.82 L CH4 g(-1) VS removed. The treatment conditions presented in this study allow for large residue quantities to be treated and large bioenergy quantities to be produced (10% higher than during conventional treatment) without increasing the anaerobic digester volume.

  14. Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

    Science.gov (United States)

    Ge, Huoqing; Batstone, Damien; Keller, Jurg

    2016-01-01

    The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

  15. Reduction of sludge production from WWTP using thermal pretreatment and enhanced anaerobic methanisation.

    Science.gov (United States)

    Graja, S; Chauzy, J; Fernandes, P; Patria, L; Cretenot, D

    2005-01-01

    The objective of the study presented here was to investigate the performance of an enhanced two-step anaerobic process for the treatment of WWTP sludge. This process was developed to answer the urgent need currently faced by WWTP operators to reduce the production of biosolids, for which disposal pathways are facing increasing difficulties. A pilot plant was operated on a full-scale WWTP (2,500 p.e.) over a period of 4 months. It consisted of a thermal pre-treatment of excess sludge at 175 degrees C and 40 min, followed by dewatering and methanisation of the centrate in a fixed-film reactor. The thermal lysis had a two-fold enhancing effect on sludge reduction efficiency: firstly, it allowed a decrease of the HRT in the methaniser to 2.9 days and secondly, it yielded biosolids with a high dewaterability. This contributed to further reductions in the final volume of sludge to be disposed of. The two-step process achieved a sludge reduction efficiency of 65% as TSS, thus giving an interesting treatment option for WWTP facing sludge disposal problems.

  16. Wheat straw pretreatment with KOH for enhancing biomethane production and fertilizer value in anaerobic digestion☆

    Institute of Scientific and Technical Information of China (English)

    Muhammad Jaffar; Yunzhi Pang; Hairong Yuan; Dexun Zou; Yanping Liu; Baoning Zhu; Rashid Mustafa Korai; Xiujin Li

    2016-01-01

    Wheat straw biodegradability during anaerobic digestion was improved by treatment with potassium hydroxide (KOH) to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations of 1%(K1), 3%(K2), 6%(K3) and 9%(K4) were tested for wheat straw pretreatment at ambient temperature with a C:N ratio of 25:1. 86%of total solids (TS), 89%of volatile solids (VS) and 22%of lignocel ulose, cellulose and hemi-cellulose (LCH) (22%) were decomposed effectively with the wheat straw pretreated by 6%KOH. Enhanced bio-gas production and cumulative biomethane yield of 258 ml·(g VS)−1 were obtained increased by 45%and 41%respectively, compared with untreated wheat straw. Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium (138%), calcium (22%) and magnesium (16%). These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value.

  17. Applicability of anaerobic nitrate-dependent Fe(II) oxidation to microbial enhanced oil recovery (MEOR).

    Science.gov (United States)

    Zhu, Hongbo; Carlson, Han K; Coates, John D

    2013-08-06

    Microbial processes that produce solid-phase minerals could be judiciously applied to modify rock porosity with subsequent alteration and improvement of floodwater sweep in petroleum reservoirs. However, there has been little investigation of the application of this to enhanced oil recovery (EOR). Here, we investigate a unique approach of altering reservoir petrology through the biogenesis of authigenic rock minerals. This process is mediated by anaerobic chemolithotrophic nitrate-dependent Fe(II)-oxidizing microorganisms that precipitate iron minerals from the metabolism of soluble ferrous iron (Fe(2+)) coupled to the reduction of nitrate. This mineral biogenesis can result in pore restriction and reduced pore throat diameter. Advantageously and unlike biomass plugs, these biominerals are not susceptible to pressure or thermal degradation. Furthermore, they do not require continual substrate addition for maintenance. Our studies demonstrate that the biogenesis of insoluble iron minerals in packed-bed columns results in effective hydrology alteration and homogenization of heterogeneous flowpaths upon stimulated microbial Fe(2+) biooxidation. We also demonstrate almost 100% improvement in oil recovery from hydrocarbon-saturated packed-bed columns as a result of this metabolism. These studies represent a novel departure from traditional microbial EOR approaches and indicate the potential for nitrate-dependent Fe(2+) biooxidation to improve volumetric sweep efficiency and enhance both the quality and quantity of oil recovered.

  18. Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology.

    Science.gov (United States)

    Dube, P J; Vanotti, M B; Szogi, A A; García-González, M C

    2016-03-01

    Gas-permeable membrane technology is useful to recover ammonia from manure. In this study, the technology was enhanced using aeration instead of alkali chemicals to increase pH and the ammonium (NH4(+)) recovery rate. Digested effluents from covered anaerobic swine lagoons containing 1465-2097 mg NH4(+)-N L(-1) were treated using submerged membranes (0.13 cm(2) cm(-3)), low-rate aeration (120 mL air L-manure(-1) min(-1)) and nitrification inhibitor (22 mg L(-1)) to prevent nitrification. The experiment included a control without aeration. The pH of the manure with aeration rose from 8.6 to 9.2 while the manure without aeration decreased from 8.6 to 8.1. With aeration, 97-99% of the NH4(+) was removed in about 5 days of operation with 96-98% recovery efficiency. In contrast, without aeration it took 25 days to treat the NH4(+). Therefore, the recovery of NH4(+) was five times faster with the low-rate aeration treatment. This enhancement could reduce costs by 70%.

  19. Mesophilic batch anaerobic co-digestion of pulp and paper sludge and monosodium glutamate waste liquor for methane production in a bench-scale digester.

    Science.gov (United States)

    Lin, Yunqin; Wang, Dehan; Li, Qing; Xiao, Minquan

    2011-02-01

    This paper presented results from anaerobic co-digestion of pulp and paper sludge (PPS) and monosodium glutamate waste liquor (MGWL). A bench-scale anaerobic digester, 10 L in volume was developed, to operate under mesophilic (37 ± 2°C) batch condition. Under versatile and reliable anaerobic conduct, high efficiency for bioconversion of PPS and MGWL were obtained in the system. The accumulative methane yield attained to 200 mL g(-1) VS(added) and the peak value of methane daily production was 0.5m(3)/(m(3)d). No inhibitions of volatile fatty acids (VFAs) and ammonia on anaerobic co-digestion were found. pH 6.0-8.0 and alkalinity 1000-4000 mg CaCO(3)/L were got without adjustment. This work showed that there was a good potential to the use of PPS and MGWL to anaerobic co-digestion for methane production. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. The Effect of the Addition of Active Digester Effluent for Start-up Accelerator in Anaerobic Digestion of Soybean Curd Industry Waste Water (Basic Research for Biogas Power Generation

    Directory of Open Access Journals (Sweden)

    Arini Wresta

    2012-12-01

    Full Text Available Biogas production from soybean curd industry waste water was studied in laboratory scale to improve the application of anaerobic digestion process. The problem with the soybean curd waste water was the fact that it does not sufficiently contain anaerobic microorganisms required in biogas production. Therefore, it is necessary to add a well-developed population of anaerobic microorganisms to accelerate the start-up of the anerobic digestion. This research was aimed to verify the influence of the addition of active digester effluent into the soybean curd waste water batches in an anaerobic digestion process. Batch experiments were done in two digesters. The first digester was only fed with soybean curd waste water while the second digester was fed with soybean curd waste water and active digester effluent from a digester processing cow manure which was very rich in anaerobic microorganism consortium. The results indicated that soybean curd industry waste water did not contain methanogenic bacteria but there existed some acidogenic bacteria. The addition of active digester effluent accelerated the anaerobic digestion start-up and directed the process pathway towards methanogenic process so that more methane was obtained. The high methane content obtained (more than 64% volume was very potential for power generation. The capacity of soybean curd industry must be as high as 697.13 kg soybean per day to generate the electric energy of 8.4 kWh.

  1. Environmental impact of rejected materials generated in organic fraction of municipal solid waste anaerobic digestion plants: Comparison of wet and dry process layout.

    Science.gov (United States)

    Colazo, Ana-Belén; Sánchez, Antoni; Font, Xavier; Colón, Joan

    2015-09-01

    Anaerobic digestion of source separated organic fraction of municipal solid waste is an increasing waste valorization alternative instead of incineration or landfilling of untreated biodegradable wastes. Nevertheless, a significant portion of biodegradable wastes entering the plant is lost in pre-treatments and post-treatments of anaerobic digestion facilities together with other improper materials such as plastics, paper, textile materials and metals. The rejected materials lost in these stages have two main implications: (i) less organic material enters to digesters and, as a consequence, there is a loss of biogas production and (ii) the rejected materials end up in landfills or incinerators contributing to environmental impacts such as global warming or eutrophication. The main goals of this study are (i) to estimate potential losses of biogas in the rejected solid materials generated during the pre- and post-treatments of two full-scale anaerobic digestion facilities and (ii) to evaluate the environmental burdens associated to the final disposal (landfill or incineration) of these rejected materials by means of Life Cycle Assessment. This study shows that there is a lost of potential biogas production, ranging from 8% to 15%, due to the loss of organic matter during pre-treatment stages in anaerobic digestion facilities. From an environmental point of view, the Life Cycle Assessment shows that the incineration scenario is the most favorable alternative for eight out of nine impact categories compared with the landfill scenario. The studied impact categories are Climate Change, Fossil depletion, Freshwater eutrophication, Marine eutrophication, Ozone depletion, Particulate matter formation, Photochemical oxidant formation, Terrestrial acidification and Water depletion.

  2. Enhanced fermentable sugar production from kitchen waste using various pretreatments.

    Science.gov (United States)

    Hafid, Halimatun Saadiah; Rahman, Nor'Aini Abdul; Md Shah, Umi Kalsom; Baharudin, Azhari Samsu

    2015-06-01

    The kitchen waste fraction in municipal solid waste contains high organic matter particularly carbohydrate that can contribute to fermentable sugar production for subsequent conversion to bioethanol. This study was carried out to evaluate the influence of single and combination pretreatments of kitchen waste by liquid hot water, mild acid pretreatment of hydrochloric acid (HCl) and sulphuric acid (H2SO4) and enzymatic hydrolysis (glucoamylase). The maximum total fermentable sugar produced after combination pretreatment by 1.5% HCl and glucoamylase consisted of 93.25 g/L glucose, 0.542 g/L sucrose, 0.348 g/L maltose, and 0.321 g/L fructose. The glucose released by the combination pretreatment method was 0.79 g glucose/g KW equivalent to 79% of glucose conversion. The effects of the pre-treatment on kitchen waste indicated that the highest solubilization was 40% by the combination method of 1.5% HCl and glucoamylase. The best combination pre-treatment gave concentrations of lactic acid, acetic acid, and propionic acid of 11.74 g/L, 6.77 g/L, and 1.02 g/L, respectively. The decrease of aliphatic absorbance bands of polysaccharides at 2851 and 2923 cm(-1) and the increase on structures of carbonyl absorbance bands at 1600 cm(-1) reflects the progress of the kitchen waste hydrolysis to fermentable sugars. Overall, 1.5% HCl and glucoamylase treatment was the most profitable process as the minimum selling price of glucose was USD 0.101/g kitchen waste. Therefore, the combination pretreatment method was proposed to enhance the production of fermentable sugar, particularly glucose from kitchen waste as the feedstock for bioethanol production.

  3. Management of source-separated organic household waste intended for anaerobic digestion

    DEFF Research Database (Denmark)

    Naroznova, Irina

    -treatment technology introduced in the present thesis is a promising solution for pre-treating SSOHW prior to AD, and it had advantages over the screw press-, disc screen- and dispersion-based pre-treatment technologies. • Any change in pre-treatment efficiency, such as ± 10% material recovered from the biomass, does...... performance, e.g. by predicting methane production and the amount of residue, and also the environmental profile, e.g. by assessing the environmental value of impact contributions when substituting fossil energy and mineral fertilisers. SSOHW is known as a highly heterogeneous waste stream, and thus its...... biodegradable matter loss. Several well-established technologies, each with its own advantages and disadvantages, are known, and these sit alongside newly emerging solutions. To ensure the environmental sustainability of the waste management sector when implementing the AD of SSOHW, it is important...

  4. Renewable Energy Production from DoD Installation Solid Wastes by Anaerobic Digestion

    Science.gov (United States)

    2016-06-01

    with AD? NO Assess local conditions YES WWTP willing to partner? YES WWTP costs less than current practice ? YES Develop stakeholder buy-in...Solid-Waste- Management -Policy- and-Guidelines.pdf. DoD. 2010. Defense Environmental Programs Annual Report to Congress - Fiscal Year 2009...Intentionally Left Blank This report was prepared under contract to the Department of Defense Environmental Security Technology Certification Program

  5. Modelling the anaerobic digestion of solid organic waste - Substrate characterisation method for ADM1 using a combined biochemical and kinetic parameter estimation approach.

    Science.gov (United States)

    Poggio, D; Walker, M; Nimmo, W; Ma, L; Pourkashanian, M

    2016-07-01

    This work proposes a novel and rigorous substrate characterisation methodology to be used with ADM1 to simulate the anaerobic digestion of solid organic waste. The proposed method uses data from both direct substrate analysis and the methane production from laboratory scale anaerobic digestion experiments and involves assessment of four substrate fractionation models. The models partition the organic matter into a mixture of particulate and soluble fractions with the decision on the most suitable model being made on quality of fit between experimental and simulated data and the uncertainty of the calibrated parameters. The method was tested using samples of domestic green and food waste and using experimental data from both short batch tests and longer semi-continuous trials. The results showed that in general an increased fractionation model complexity led to better fit but with increased uncertainty. When using batch test data the most suitable model for green waste included one particulate and one soluble fraction, whereas for food waste two particulate fractions were needed. With richer semi-continuous datasets, the parameter estimation resulted in less uncertainty therefore allowing the description of the substrate with a more complex model. The resulting substrate characterisations and fractionation models obtained from batch test data, for both waste samples, were used to validate the method using semi-continuous experimental data and showed good prediction of methane production, biogas composition, total and volatile solids, ammonia and alkalinity.

  6. Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Houbron, E.; Rustrian, E. [Universidad Veracruzana, Orizaba, Ver. (Mexico). Facultad de Ciencias Quimicas; Larrinaga, A. [Instituto tecnologico de Orizaba, Ver. (Mexico)

    2003-07-01

    This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g.l{sup -1}.d{sup -1} and 0.5 COD g.l{sup -1}.d{sup -1}. The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g.l{sup -1} respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD.l{sup -1}.d{sup -1} and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD.l{sup -1}, and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH{sub 4} and 20% CO{sub 2}. These results show that a humid coffee 'Beneficio' processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH{sub 4} m{sup 3}.d{sup -1}. This represents an increase in methane production by a factor 3 to 5 compared to a 'Beneficio' using anaerobic digestion only for the treatment of its wastewater. (author)

  7. Assessing anaerobic co-digestion of pig manure with agroindustrial wastes: the link between environmental impacts and operational parameters.

    Science.gov (United States)

    Rodriguez-Verde, Ivan; Regueiro, Leticia; Carballa, Marta; Hospido, Almudena; Lema, Juan M

    2014-11-01

    Anaerobic co-digestion (AcoD) is established as a techno-economic profitable process by incrementing biogas yield (increased cost-efficiency) and improving the nutrient balance (better quality digestate) in comparison to mono-digestion of livestock wastes. However, few data are available on the environmental consequences of AcoD and most of them are mainly related to the use of energy crops as co-substrates. This work analysed the environmental impact of the AcoD of pig manure (PM) with several agroindustrial wastes (molasses, fish, biodiesel and vinasses residues) using life cycle assessment (LCA) methodology. For comparative purposes, mono digestion of PM has also been evaluated. Four out of six selected categories (acidification, eutrophication, global warming and photochemical oxidation potentials) showed environmental impacts in all the scenarios assessed, whereas the other two (abiotic depletion and ozone layer depletion potentials) showed environmental credits, remarking the benefit of replacing fossil fuels by biogas. This was also confirmed by the sensitivity analysis applied to the PM quality (i.e. organic matter content) and the avoided energy source demonstrating the importance of the energy recovery step. The influence of the type of co-substrate could not be discerned; however, a link between the environmental performance and the hydraulic retention time, the organic loading rate and the nutrient content in the digestate could be established. Therefore, LCA results were successfully correlated to process variables involved in AcoD, going a step further in the combination of techno-economic and environmental feasibilities. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Modelling of slaughterhouse solid waste anaerobic digestion: determination of parameters and continuous reactor simulation.

    Science.gov (United States)

    López, Iván; Borzacconi, Liliana

    2010-10-01

    A model based on the work of Angelidaki et al. (1993) was applied to simulate the anaerobic biodegradation of ruminal contents. In this study, two fractions of solids with different biodegradation rates were considered. A first-order kinetic was used for the easily biodegradable fraction and a kinetic expression that is function of the extracellular enzyme concentration was used for the slowly biodegradable fraction. Batch experiments were performed to obtain an accumulated methane curve that was then used to obtain the model parameters. For this determination, a methodology derived from the "multiple-shooting" method was successfully used. Monte Carlo simulations allowed a confidence range to be obtained for each parameter. Simulations of a continuous reactor were performed using the optimal set of model parameters. The final steady-states were determined as functions of the operational conditions (solids load and residence time). The simulations showed that methane flow peaked at a flow rate of 0.5-0.8 Nm(3)/d/m(reactor)(3) at a residence time of 10-20 days. Simulations allow the adequate selection of operating conditions of a continuous reactor.

  9. Wastes valorization from Rhodosporidium toruloides NCYC 921 production and biorefinery by anaerobic digestion.

    Science.gov (United States)

    Batista, Ana Paula; López, Emílio Palomo; Dias, Carla; Lopes da Silva, Teresa; Marques, Isabel Paula

    2017-02-01

    Yeast production and biomass biorefinery processes for lipid and carotenoid extraction generate residues that can be used as substrates for anaerobic digestion. Glucose and carob pulp syrups were used as carbon sources to produce the yeast biomass. The yeast cultivation broth, yeast biomass residues (after carotenoid and lipid extraction) and the carob pulp solid residues obtained from the extraction of sugars were used to produce biogas by applying different Substrate/Inoculum ratios (S/I of 0.5 and 0.75). For all the residues studied, the digestions at the S/I ratio of 0.75 provided higher biogas yields than those carried out at the S/I ratio of 0.5. The best results in terms of biogas production and methane yield were observed for the yeast residue digestion at S/I of 0.75 (65.9mL, 333.7mLg(-1)VS(-1) substrate). As monitored through flow cytometry, its bacterial consortium showed the lowest proportion of injured cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Fertilizer potential of liquid and solid effluent from thermophilic anaerobic digestion of poultry waste.

    Science.gov (United States)

    Liedl, B E; Bombardiere, J; Chaffield, J M

    2006-01-01

    Thermophilic anaerobic treatment of poultry litter produces an effluent stream of digested materials that can be separated into solid and liquid fractions for use as a crop fertilizer. The majority of the phosphorus is partitioned into the solid fraction while the majority of the nitrogen is present in the liquid fraction in the form of ammonium. These materials were tested over six years as an alternative fertilizer for the production of vegetable, fruit, and grassland crops. Application of the solids as a field crop fertilizer for vegetables and blueberries resulted in lower yields than the other fertilizer treatments, but an increase in soil phosphorus over a four-year period. Application of the digested liquids on grass and vegetable plots resulted in similar or superior yields to plots treated with commercially available nitrogen fertilizers. Hydroponic production of lettuce using liquid effluent was comparable to a commercial hydroponic fertilizer regime; however, the effluent treatment for hydroponic tomato production required supplementation and conversion of ammonium to nitrate. While not a total fertilizer solution, our research shows the effectiveness of digested effluent as part of a nutrient management program which could turn a livestock residuals problem into a crop nutrient resource.

  11. Combined effect of crude fat content and initial substrate concentration on batch anaerobic digestion characteristics of food waste.

    Science.gov (United States)

    Zhang, Wanqin; Lang, Qianqian; Fang, Ming; Li, Xin; Bah, Hamidou; Dong, Hongmin; Dong, Renjie

    2017-05-01

    The mesophilic anaerobic digestion (AD) characteristics of food waste (FW) with different crude fat (CF) contents and four initial substrate concentrations (4, 6, 8, and 10gVS/L) were investigated. The maximum methane yields of FW with CF contents of 15%, 20%, 25%, 30%, and 35% were 565.0, 580.2, 606.0, 630.2 and 573.0mLCH4/gVSadded, respectively. An acidification trend with a drop in pH (0.4) were found for CF contents of 30% (10gVS/L) and 35% (8 and 10gVS/L). A 35% CF content in FW led to decrease in the first-order degradation constant of approximately by 40%. The modified Gompertz model showed that the lag phase (λ) was prolonged from 0.4 to 7.1days when the CF content in FW and initial substrate concentration were increased to 35% and 10gVS/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Two-stage high-rate biogas (H2 and CH4) production from food waste using anaerobic mixed microflora

    Science.gov (United States)

    Xu, K.; Lee, D.; Kobayashi, T.; Ebie, Y.; Li, Y.; Inamori, Y.

    2010-12-01

    To achieve the high-rate H2 and CH4 production from food waste using fermentative anaerobic microflora, the effects of carbonate-alkalinity in the recirculated digestion sludge on continuous two-stage fermentation were investigated. Higher H2 production rate of 2.9 L-H2/L/day was achieved at the recycle ratio of 1.0 in an alkalinity range of 9000 to 10000 mg-CaCO3/L. The maximum CH4 production rate was stably maintained at the range of 1.85 to 1.88 L-CH4/L/day without alkalinity change. Carbonate alkalinity in digestion sludge could reduce the H2 partial pressure in the headspace of the fermentation reactors, and improve a biogas production capacity in the two-stage fermentation process. The average volatile solids degradation rate in the overall process increased as the digestion sludge recycle increased from 0.5 to 1.0. These results show that the alkalinity in recycle of the digestion sludge is crucial factor in determining biogas (H2 and CH4) production capacity and reducing the total solids.

  13. Bio-hydrolysis and bio-hydrogen production from food waste by thermophilic and hyperthermophilic anaerobic process.

    Science.gov (United States)

    Algapani, Dalal E; Qiao, Wei; Su, Min; di Pumpo, Francesca; Wandera, Simon M; Adani, Fabrizio; Dong, Renjie

    2016-09-01

    High-temperature pretreatment plays a key role in the anaerobic digestion of food waste (FW). However, the suitable temperature is not yet determined. In this work, a long-term experiment was conducted to compare hydrolysis, acidogenesis, acetogenesis, and hydrogen production at 55°C and 70°C, using real FW in CSTR reactors. The results obtained indicated that acidification was the rate-limiting step at both temperatures with similar process kinetics characterizations. However, the thermophilic pretreatment was more advantageous than the hyperthermophilic with suspended solids solubilization of 47.7% and 29.5% and total VFA vs. soluble COD ratio of 15.2% and 4.9%, for thermophilic and hyperthermophilic treatment, respectively, with a hydrolytic reaction time (HRT) of 10days and an OLR of 14kgCOD/m(3)d. Moreover, stable hydrogen yield (70.7ml-H2/gVSin) and content in off gas (58.6%) was achieved at HRT 5days, pH 5.5, and temperature of 55°C, as opposed to 70°C.

  14. Long-term effect of the antibiotic cefalexin on methane production during waste activated sludge anaerobic digestion.

    Science.gov (United States)

    Lu, Xueqin; Zhen, Guangyin; Liu, Yuan; Hojo, Toshimasa; Estrada, Adriana Ledezma; Li, Yu-You

    2014-10-01

    Long-term experiments herein were conducted to investigate the effect of cefalexin (CLX) on methane production during waste activated sludge (WAS) anaerobic digestion. CLX exhibited a considerable inhibition in methane production during the initial 25 days while the negative effect attenuated subsequently and methane production recovered depending on CLX doses used (600 and 1000 mg/L). The highest methane yield reached 450 mL at 1000 mg-CLX/L after 157 days of digestion, 63.8% higher than CLX-free one. Stimulated excretion of extracellular polymeric substances (EPS) by CLX served as microbial protecting layers, creating a suitable environment for microbes' growth and fermentation. Further examination via ultraviolet visible (UV-Vis) spectra also verified the elevated slime EPS, LB-EPS and TB-EPS indicated by UV-254 in the presence of CLX. Unlike the commonly accepted adverse effect, this study demonstrated the beneficial role of CLX in methane production, providing new insights into its true environmental impacts.

  15. Proteolytic bacterial dominance in a full-scale municipal solid waste anaerobic reactor assessed by 454 pyrosequencing technology.

    Science.gov (United States)

    Cardinali-Rezende, Juliana; Rojas-Ojeda, Patricia; Nascimento, Andréa M A; Sanz, José L

    2016-03-01

    Biomethanization entails a good means to reduce the organic fraction (OF) derived from municipal solid wastes (MSW). The bacterial diversity of a full scale MSW anaerobic reactor located in Madrid (Spain) was investigated using high-throughput 454 pyrosequencing. Even though the proteolytic bacteria prevailed throughout all of the process, community shifts were observed from the start-up to the steady-state conditions, with an increasing biodiversity displayed over time. The Bacteroidetes and the Firmicutes were the majority phyla: 55.1 and 40.2% (start-up) and 18.7 and 78.7 (steady-state) of the total reads. The system's lack of evenness remains noteworthy as the sequences affiliated to the proteolytic non-saccharolytic Proteiniphylum, Gallicola and Fastidiosipila genera, together with the saccharolytic Saccharofermentans, were predominant on the system and this predominance appears to correlate with the presence of a high ammonium concentration. The 454 pyrosequencing revealed a great diversity of rare organisms which seemingly do not sustain any metabolic roles in the course of the OF-MSW degradation. However, this scarce and unique microbiota can confer great resilience to the system as a buffer against nutritional and environmental changing conditions, thus opening the door to increase the current knowledge about the bacterial community dynamics taking place during MSW treatment processes.

  16. Valorisation of biodiesel production wastes: Anaerobic digestion of residual Tetraselmis suecica biomass and co-digestion with glycerol.

    Science.gov (United States)

    Santos-Ballardo, David U; Font-Segura, Xavier; Ferrer, Antoni Sánchez; Barrena, Raquel; Rossi, Sergio; Valdez-Ortiz, Angel

    2015-03-01

    One of the principal opportunity areas in the development of the microalgal biodiesel industry is the energy recovery from the solid microalgal biomass residues to optimise the fuel production. This work reports the cumulative methane yields reached from the anaerobic digestion of the solid microalgal biomass residues using different types of inocula, reporting also the improvement of biogas production using the co-digestion of microalgal biomass with glycerol. Results demonstrate that the solid microalgal biomass residues showed better biogas production using a mesophilic inoculum, reaching almost two-fold higher methane production than under thermophilic conditions. Furthermore, the solid microalgal biomass residues methane production rate showed an increase from 173.78 ± 9.57 to 438.46 ± 40.50 mL of methane per gram of volatile solids, when the co-digestion with glycerol was performed. These re