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Sample records for anaerobic digester performance

  1. Anaerobic digestion: technology transfer, engineering performance and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F.; Traverso, P.G.; Ganapini, W.

    1987-10-01

    The chemical, technological and process aspects of anaerobic digestion process are analysed on the basis of the Authors' experience and of scientific literature. Emphasis is put on the necessity of integrating the presentation of experimental data and some suggestions are common to those of the EEC to improve the knowledge of the process. An analysis of the types of full-scale digesters used in Europe and in the USA is supplied and suggestions are proposed on the future development of anaerobic technology with the aim of improving performance and efficiency.

  2. Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival.

    Science.gov (United States)

    Chen, Le; Jian, Shanshan; Bi, Jinhua; Li, Yunlong; Chang, Zhizhou; He, Jian; Ye, Xiaomei

    2016-05-01

    Tomato plant waste (TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS (total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic (37±1°C) and room (20-25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416L/kg VS (volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR (polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA (volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.

  3. Anaerobic Digestion.

    Science.gov (United States)

    Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

    2017-04-09

    The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

  4. Design considerations and operational performance of Anaerobic Digester: A Review

    Directory of Open Access Journals (Sweden)

    Muzaffar Ahmad Mir

    2016-04-01

    Full Text Available Due to the decline in fossil fuel reservoirs, the researchers emphasized more on the production of biogas from organic waste. Producing the renewable energy from biodegradable waste helps to overcome the energy crisis and solid waste management, done by anaerobic digestion. Anaerobic digestion is controlled breakdown of organic matter into methane gas (60%, carbon dioxide (40%, trace components along with digested used as soil conditioner. However there is vast dearth of literature regarding the design considerations. The batch digestion system yields a cost-effective and economically viable means for conversion of the food waste to useful energy. It is therefore recommended that such process can be increasingly employed in order to get and simultaneously protect the environment .This paper aims to draw key analysis and concern about the design considerations, analysis of gas production, substrates and inoculums utilization, uses and impacts of biogas.

  5. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale

  6. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale mu

  7. INCREASING ANAEROBIC DIGESTION PERFORMANCE OF WASTEWATER WITH CO-DIGESTION USING DECANTER CAKE

    OpenAIRE

    Thaniya Kaosol; Narumol Sohgrathok

    2014-01-01

    Low biogas production in the frozen seafood wastewater anaerobic digestion is observed due to the low organic and Total Solids (TS) contents in the wastewater. In this research the decanter cake will be used in the anaerobic co-digestion process to improve the biogas production rate. The effect of co-digestion and Hydraulic Retention Time (HRT) will be investigated using the continuously stirred tank reactors under anaerobic conditions. Moreover, the study determines the biogas production pot...

  8. 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....

  9. INCREASING ANAEROBIC DIGESTION PERFORMANCE OF WASTEWATER WITH CO-DIGESTION USING DECANTER CAKE

    Directory of Open Access Journals (Sweden)

    Thaniya Kaosol

    2014-01-01

    Full Text Available Low biogas production in the frozen seafood wastewater anaerobic digestion is observed due to the low organic and Total Solids (TS contents in the wastewater. In this research the decanter cake will be used in the anaerobic co-digestion process to improve the biogas production rate. The effect of co-digestion and Hydraulic Retention Time (HRT will be investigated using the continuously stirred tank reactors under anaerobic conditions. Moreover, the study determines the biogas production potential of different HRTs and that of wastewater digestion alone. The anaerobic co-digestion is operated in continuous with continuously stirred reactors at HRT of 10, 20 and 30 days. The mechanical stirring units of all reactors are operated automatically. The stirring action occurred continuously during the experiments. The anaerobic co-digestion results show that the anaerobic co-digestion provides higher biogas production rate and higher methane yield than that of the wastewater digestion alone. The optimum HRT of the anaerobic co-digestion is 20 days. This reactor produces 2.88 L day-1, with 64.5% of methane and the maximum methane production rate of 1.87 L day-1 and the methane yield of 0.321 l CH4/g CODremoved. The anaerobic co-digestion of wastewater with decanter cake provides the higher methane yield potential production than that provided by the wastewater digestion alone at the ambient temperature. The best HRT is 20 days for anaerobic co-digestion between the wastewater and decanter cake. The experimental results reveal that HRT and co-digestion are the parameters that can affect the biogas production and methane yield.

  10. 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.

  11. 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...

  12. Effects of dairy manure and corn stover co-digestion on anaerobic microbes and corresponding digestion performance.

    Science.gov (United States)

    Yue, Zhengbo; Chen, Rui; Yang, Fan; MacLellan, James; Marsh, Terence; Liu, Yan; Liao, Wei

    2013-01-01

    This study investigated the effects of corn stover as a supplemental feed on anaerobic digestion of dairy manure under different hydraulic retention times (HRT). The results elucidated that both HRT and corn stover supplement significantly influenced microbial community and corresponding anaerobic digestion performance. The highest biogas production of 497 mL per gram total solid loading per day was observed at a HRT of 40 days from digestion of manure supplemented with corn stover. Biogas production was closely correlated with the populations of Bacteroidetes, Clostridia and methanogens. Composition of the solid digestate (AD fiber) from the co-digestion of corn stover and dairy manure was similar to the digestion of dairy manure. However, the hydrolysis of AD fiber was significantly (P < 0.05) different among the different digestions. Both HRT and feed composition influenced the hydrolyzability of AD fiber via shifting the composition of microbial community.

  13. Perspectives for anaerobic digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    2003-01-01

    to the soil. Anaerobic digestion (AD) is one way of achieving this goal and it will furthermore, reduce energy consumption or may even be net energy producing. This chapter aims at provide a basic understanding of the world in which anaerobic digestion is operating today. The newest process developments...

  14. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  15. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  16. 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.

  17. 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.

  18. Performance and Analysis of Floating dome Anaerobic Digester with Wet and Dry Feedstock

    Science.gov (United States)

    Sathish, S.; Parthiban, A.; Venugopal, S.; Jothi Prakash, V. M.

    2017-03-01

    The objective of this study is to evaluate the feasibility of anaerobic digestion to generate biogas yield and it’s performed using wet and dry feed stock. The laboratory experiment is conducted in a floating dome type anaerobic digester with 1m3 capacity. It is made up of fibre material at continues process. The starter cowdung used as an inoculum of the anaerobic digester. Then raw materials feeded as a wet type wheat straw and dry type wheat straw is the ratio of 1:1 waste/water in both the experiments wet and dry wheat straw. In this experiments are fermented at 30ºC to 35ºC temperature is maintained. The daily biogas yield, cumulative biogas yield, pH, CH4, and hydro retention time these parameters is studied and analysed. The maximum daily biogas is 25liters and 42% of methane is achieved in dry wheat straw at 15th day of digestion. The highest gas yield obtained in dry condition compare to wet condition and acid level also decreased in wet digestion.

  19. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  20. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters.

    Science.gov (United States)

    Cabrol, Léa; Urra, Johana; Rosenkranz, Francisca; Kroff, Pablo Araya; Plugge, Caroline M; Lesty, Yves; Chamy, Rolando

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale municipal WWTP in Santiago de Chile, and fed with either primary or mixed sewage sludge. AD performance was evaluated by volatile fatty acid (VFA) and biogas production monitoring. Archaeal community structure was characterized by 16S rRNA denaturing gradient gel electrophoresis and band sequencing. In the primary sludge digester, a single PAA pulse at 200 mg L(-1) was sufficient to affect AD performance and archaeal community structure, resulting in long-term VFA accumulation, reduced biogas production and community shift from dominant acetoclastic (Methanosaeta concilii) to hydrogenotrophic (Methanospirillum hungatei) methanogens. By contrast, AD performance and archaeal community structure in the mixed sludge digester were stable and resistant to repeated PAA pulses at 200 and 600 mg L(-1). This work demonstrated that the effect of PAA pulses on methanogenic activity and archaeal community structure differed according to AD substrate, and suggests that better insights of the correlations between archaeal population dynamics and functional performance could help to better face toxic shocks in AD.

  1. The effect of managing nutrients in the performance of anaerobic digesters of municipal wastewater treatment plants.

    Science.gov (United States)

    Demirer, Sibel Uludag; Taskin, Bilgin; Demirer, Goksel N; Duran, Metin

    2013-09-01

    Is it possible to create conditions in the anaerobic digesters to control nutrients without changing the performance of a reactor? This study investigates an answer for this question. To this purpose, anaerobic reactors are operated at high concentrations of Mg(2+) ion to harvest the nutrient ions (NH4 (+) and PO4 (3-)) in the form of struvite, that is, magnesium ammonium phosphate. The effects of this modification on the anaerobic digestion of sewage sludge were investigated in terms of chemical oxygen demand (COD) removal and cumulative CH4 production as well as the changes in the biological diversity. The results showed that approximately 50 % of the nutrients (NH4 (+) and PO4 (3-)) were removed regardless of the method adopted for the addition of Mg(2+) ion, slug or daily dosing. The numbers of Methanosaeta and Methanosarcina in the samples withdrawn prior to and after the addition of Mg(2+) did not show significant difference according to the results obtained from qPCR analyses. The research results showed that the addition of Mg(2+) into the anaerobic digesters in municipal wastewater treatment facilities may help to remove the nutrients from the effluent while recovering in their solid forms.

  2. 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.

  3. Microorganism-regulated mechanisms of temperature effects on the performance of anaerobic digestion.

    Science.gov (United States)

    Lin, Qiang; He, Guihua; Rui, Junpeng; Fang, Xiaoyu; Tao, Yong; Li, Jiabao; Li, Xiangzhen

    2016-06-03

    Temperature is an important factor determining the performance and stability of the anaerobic digestion process. However, the microorganism-regulated mechanisms of temperature effects on the performance of anaerobic digestion systems remain further elusive. To address this issue, we investigated the changes in composition, diversity and activities of microbial communities under temperature gradient from 25 to 55 °C using 16S rRNA gene amplicon sequencing approach based on genomic DNA (refer to as "16S rDNA") and total RNA (refer to as "16S rRNA"). Microbial community structure and activities changed dramatically along the temperature gradient, which corresponded to the variations in digestion performance (e.g., daily CH4 production, total biogas production and volatile fatty acids concentration). The ratios of 16S rRNA to 16S rDNA of microbial taxa, as an indicator of the potentially relative activities in situ, and whole activities of microbial community assessed by the similarity between microbial community based on 16S rDNA and rRNA, varied strongly along the temperature gradient, reflecting different metabolic activities. The daily CH4 production increased with temperature from 25 to 50 °C and declined at 55 °C. Among all the examined microbial properties, the whole activities of microbial community and alpha-diversity indices of both microbial communities and potentially relative activities showed highest correlations to the performance. The whole activities of microbial community and alpha-diversity indices of both microbial communities and potentially relative activities were sensitive indicators for the performance of anaerobic digestion systems under temperature gradient, while beta-diversity could predict functional differences. Microorganism-regulated mechanisms of temperature effects on anaerobic digestion performance were likely realized through increasing alpha-diversity of both microbial communities and potentially relative activities to supply

  4. 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.

  5. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  6. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  7. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the

  8. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  9. Anaerobic digestion performance of vinegar residue in continuously stirred tank reactor.

    Science.gov (United States)

    Li, Lin; Feng, Lu; Zhang, Ruihong; He, Yanfeng; Wang, Wen; Chen, Chang; Liu, Guangqing

    2015-06-01

    Anaerobic digestion (AD) of vinegar residue was investigated in continuously stirred tank reactor (CSTR). The influence of organic loading rate (OLR) and effluent recirculation on AD performance of vinegar residue was tested. Five OLRs, 1.0, 1.5, 2.0, 2.5, and 3.0 g(vs) L(-1) d(-1), were used. The highest volumetric methane productivity of 581.88 mL L(-1) was achieved at OLR of 2.5 g(vs) L(-1) d(-1). Effluent reflux ratio was set as 50%, the results showed that effluent recirculation could effectively neutralize the acidity of vinegar residue, raise the pH of the feedstock, and enhance the buffering capacity of the AD system. Anaerobic digestion of vinegar residue could be a promising way not only for converting this waste into gas energy but also alleviating environmental pollution which might be useful for future industrial application.

  10. 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.

  11. 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

  12. Anaerobic digestion for simultaneous sewage sludge treatment and CO biomethanation: process performance and microbial ecology

    DEFF Research Database (Denmark)

    Luo, Gang; Wang, Wen; Angelidaki, Irini

    2013-01-01

    in an anaerobic reactor was presented. Batch experiments showed that CO was inhibitory to methanogens, but not to bacteria, at CO partial pressure between 0.25 and 1 atm under thermophilic conditions. During anaerobic digestion of sewage sludge supplemented with CO added through a hollow fiber membrane (HFM...

  13. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  14. Performance of thermophilic anaerobic digesters using inoculum mixes with enhanced methanogenic diversity

    KAUST Repository

    Ghanimeh, Sophia

    2017-05-30

    BACKGROUND Reportedly, various mixes of seeds were quasi-randomly selected to startup anaerobic digesters. In contrast, this study examines the impact of inoculating thermophilic anaerobic digesters with a designed mix of non-acclimated seeds based on their methanogen composition, using Quantitative Polymerase Chain Reaction (QPCR) of 16S rRNA gene, to achieve high abundance and diversity of methanogens. RESULTS Based on QPCR results, two seed mixes were selected to inoculate two anaerobic digesters: digester (A) was inoculated with a control seed consisting of digestate, manure, and activated sludge; and digester (B) was inoculated with a further methanogen-enriched seed consisting of the control seed with added compost and leachate. Both seed combinations yielded a balanced microflora that is able to achieve a successful startup. However, upon reaching steady state, digester B exhibited lower propionate levels, resulting in lower VFA concentration and increased buffering capacity, indicating greater stability. Acetotrophs and hydrogenotrophs were dominated by Methanosarcinaceae and Methanobacteriales, respectively, in both digesters, exhibiting an average ratio of 66-to-34% in A and 76-to-24% in B during steady state. CONCLUSION The inoculation strategy in digester B resulted in improved stability, lower propionate concentration and 10% higher relative abundance of acetotrophs.

  15. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulate...

  16. 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.

  17. 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}.

  18. Transition of municipal sludge anaerobic digestion from mesophilic to thermophilic and long-term performance evaluation.

    Science.gov (United States)

    Tezel, Ulas; Tandukar, Madan; Hajaya, Malek G; Pavlostathis, Spyros G

    2014-10-01

    Strategies for the transition of municipal sludge anaerobic digestion from mesophilic to thermophilic were assessed and the long-term stability and performance of thermophilic digesters operated at a solids retention time of 30days were evaluated. Transition from 36°C to 53.3°C at a rate of 3°C/day resulted in fluctuation of the daily gas and volatile fatty acids (VFAs) production. Steady-state was reached within 35days from the onset of temperature increase. Transitions from either 36 or 53.3°C to 60°C resulted in relatively stable daily gas production, but VFAs remained at very high levels (in excess of 5000mg COD/L) and methane production was lower than that of the mesophilic reactor. It was concluded that in order to achieve high VS and COD destruction and methane production, the temperature of continuous-flow, suspended growth digesters fed with mixed municipal sludge should be kept below 60°C.

  19. Effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester.

    Science.gov (United States)

    Espinosa-Solares, Teodoro; Valle-Guadarrama, Salvador; Bombardiere, John; Domaschko, Max; Easter, Michael

    2009-05-01

    The effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester treating chicken litter, under thermophilic conditions, has been studied. Heating strategy was evaluated using three different spans (0.2 degrees C, 0.6 degrees C, and 1.0 degree C) for triggering the temperature control system from target temperature (56.7 degrees C). The hydraulic retention time in the pilot plant digester was in the range of 32 to 37 days, varying the total solids concentration fed from 5% to 6%. The results showed that under the experimental conditions, heating was the most energy-demanding process with 95.5% of the energy used. Increments up to 7.5% and 3.8%, respectively, on mechanical and heating power consumption, were observed as the span, for triggering the temperature control system from target temperature, was increased. Under the experimental conditions studied here, an increment of 30.6% on the global biodigester performance index was observed when a span of 1.0 degree C was compared to the one of 0.2 degrees C.

  20. Implementing Livestock Anaerobic Digestion Projects

    Science.gov (United States)

    Page provides information to help make an informed decision about installing an anaerobic digester. Is it a good match for a farm’s organic waste, project financing, development guidelines and permit requirements?

  1. Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

    Science.gov (United States)

    Tomei, M Concetta; Mosca Angelucci, Domenica; Levantesi, Caterina

    2016-03-01

    Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion.

  2. 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

  3. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær

    2001-01-01

    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern requireme...

  4. New perspectives in anaerobic digestion.

    NARCIS (Netherlands)

    Lier, van J.B.; Tilche, A.; Ahring, B.K.; Macarie, H.; Moletta, R.; Dohanyos, M.; Hulshoff Pol, L.W.; Lens, P.N.L.; Verstraete, W.

    2001-01-01

    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern

  5. 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).

  6. Bio-energy conversion performance, biodegradability, and kinetic analysis of different fruit residues during discontinuous anaerobic digestion.

    Science.gov (United States)

    Zhao, Chen; Yan, Hu; Liu, Yan; Huang, Yan; Zhang, Ruihong; Chen, Chang; Liu, Guangqing

    2016-06-01

    Huge amounts of fruit residues are produced and abandoned annually. The high moisture and organic contents of these residues makes them a big problem to the environment. Conversely, they are a potential resource to the world. Anaerobic digestion is a good way to utilize these organic wastes. In this study, the biomethane conversion performances of a large number of fruit residues were determined and compared using batch anaerobic digestion, a reliable and easily accessible method. The results showed that some fruit residues containing high contents of lipids and carbohydrates, such as loquat peels and rambutan seeds, were well fit for anaerobic digestion. Contrarily, residues with high lignin content were strongly recommended not to be used as a single substrate for methane production. Multiple linear regression model was adopted to simulate the correlation between the organic component of these fruit residues and their experimental methane yield, through which the experimental methane yield could probably be predicted for any other fruit residues. Four kinetic models were used to predict the batch anaerobic digestion process of different fruit residues. It was shown that the modified Gompertz and Cone models were better fit for the fruit residues compared to the first-order and Fitzhugh models. The first findings of this study could provide useful reference and guidance for future studies regarding the applications and potential utilization of fruit residues.

  7. Improving the mixing performances of rice straw anaerobic digestion for higher biogas production by computational fluid dynamics (CFD) simulation.

    Science.gov (United States)

    Shen, Fei; Tian, Libin; Yuan, Hairong; Pang, Yunzhi; Chen, Shulin; Zou, Dexun; Zhu, Baoning; Liu, Yanping; Li, Xiujin

    2013-10-01

    As a lignocellulose-based substrate for anaerobic digestion, rice straw is characterized by low density, high water absorbability, and poor fluidity. Its mixing performances in digestion are completely different from traditional substrates such as animal manures. Computational fluid dynamics (CFD) simulation was employed to investigate mixing performances and determine suitable stirring parameters for efficient biogas production from rice straw. The results from CFD simulation were applied in the anaerobic digestion tests to further investigate their reliability. The results indicated that the mixing performances could be improved by triple impellers with pitched blade, and complete mixing was easily achieved at the stirring rate of 80 rpm, as compared to 20-60 rpm. However, mixing could not be significantly improved when the stirring rate was further increased from 80 to 160 rpm. The simulation results agreed well with the experimental results. The determined mixing parameters could achieve the highest biogas yield of 370 mL (g TS)(-1) (729 mL (g TS(digested))(-1)) and 431 mL (g TS)(-1) (632 mL (g TS(digested))(-1)) with the shortest technical digestion time (T 80) of 46 days. The results obtained in this work could provide useful guides for the design and operation of biogas plants using rice straw as substrates.

  8. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær

    2001-01-01

    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...... requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader...

  9. Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure

    NARCIS (Netherlands)

    Timmerman, M.; Schuman, E.; Eekert, M.; Riel, van J.W.

    2015-01-01

    Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on

  10. Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure

    NARCIS (Netherlands)

    Timmerman, M.; Schuman, E.; Eekert, M.; Riel, van J.W.

    2015-01-01

    Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on

  11. Effect of Diurnally Cyclic Temperature on the Performance of a Continuous Mix Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2011-01-01

    Full Text Available Problem statement: Concentrated livestock production is a major contributor to environmental problems through the production of large quantity of husks on relatively small land area. Anaerobic digestion represents a valuable means of cover by these husks into methane while reducing manure pollution problems. Methodology: An experimental apparatus, including data acquisition and control system, was developed and used to investigate the effects of two diurnally cyclic temperature ranges (20-40 and 15-25°C and four levels of hydraulic retention times (25, 20, 15 and 10 d on the performance of anaerobic reactors operated on screened dairy manure. Results: The reactor temperature exhibited a lag relative to the chamber temperature. For the 20-40°C temperature cycles, the average lag at the maximum chamber temperature was 3.75 h while the lag at the minimum chamber temperature was 4.37 h. For the 15-25°C temperature cycle, the average lag at maximum chamber temperatures was 3.61 while the lag of the minimum chamber temperature was 4.34 h. The effluent solids content, total Kjeldahl nitrogen and ammonium nitrogen concentrations were not adversely affected by the reactor diurnally cyclic temperature. The observed values of these parameters compared fairly well with the values obtained by other researchers. The effluent total solids, volatile suspended solids, TKN, NH4-N and methane content of the biogas diurnally cyclic patterns were out of phase with the diurnally cyclic pattern of the reactor temperature by about 12 h under most of the investigated operating conditions. The pH and the carbon dioxide content of the biogas all exhibited a diurnally cyclic pattern which was in phase with the reactor diurnally cyclic temperature. The reductions in total solids, total suspended solids, fixed suspended solids, total Kjeldahl nitrogen, ammonium nitrogen and methane yield were all significantly affected by the diurnal temperature range and hydraulic

  12. 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.

  13. Balancing hygienization and anaerobic digestion of raw sewage sludge.

    Science.gov (United States)

    Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

    2012-12-01

    The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery.

  14. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    Science.gov (United States)

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  15. Performance evaluation of a two-phase anaerobic digestion process of synthetic domestic wastewater at ambient temperature.

    Science.gov (United States)

    Guerrero, L; Montalvo, S; Coronado, E; Chamy, R; Poirrier, P; Crutchik, D; Sánchez, E; De La Rubia, M A; Borja, R

    2009-06-01

    A two-phase anaerobic digestion process of synthetic domestic wastewater was studied at ambient temperature in mild to cold climates. The hydrolytic stage was carried out in a continuous stirred tank reactor with an effective volume of 1.2 L. The hydrolytic reactor operated at hydraulic retention times (HRTs) in the range of 1.3 to 2.7 h, which allowed for optimum HRT to be obtained in order to achieve a maximum amount of soluble COD. For the methanogenic stage, an up-flow anaerobic filter with a volume of 1.35 L and corrugated plastic rings as biomass immobilization support were used. During the investigation, the ambient temperature ranged between 21 degrees C and 24 degrees C. Synthetic domestic wastewater with a COD of 700 mg/L was used as substrate. The study was performed at total organic loading rates (OLR(T)) of 2.0-4.3 g COD/L. d, with a global HRT (including both hydrolytic and methanogenic stages) of 2.8-5.8 hours. A maximum percentage of organic matter removed of 88% was achieved at a global HRT of 5.8 hours. Under these operating conditions, the production of biogas was 97% higher than that obtained in the one-phase anaerobic digestion process. Additionally, the kinetics involved in the hydrolytic stage was determined using the Contois kinetic model, which adequately predicted the experimental results.

  16. Kinetics and modeling of anaerobic digestion process

    DEFF Research Database (Denmark)

    2003-01-01

    Anaerobic digestion modeling started in the early 1970s when the need for design and efficient operation of anaerobic systems became evident. At that time not only was the knowledge about the complex process of anaerobic digestion inadequate but also there were computational limitations. Thus...

  17. Reactor performance of a 750 m(3) anaerobic digestion plant: varied substrate input conditions impacting methanogenic community.

    Science.gov (United States)

    Wagner, Andreas Otto; Malin, Cornelia; Lins, Philipp; Gstraunthaler, Gudrun; Illmer, Paul

    2014-10-01

    A 750 m(3) anaerobic digester was studied over a half year period including a shift from good reactor performance to a reduced one. Various abiotic parameters like volatile fatty acids (VFA) (formic-, acetic-, propionic-, (iso-)butyric-, (iso-)valeric-, lactic acid), total C, total N, NH4 -N, and total proteins, as well as the organic matter content and dry mass were determined. In addition several process parameters such as temperature, pH, retention time and input of substrate and the concentrations of CH4, H2, CO2 and H2S within the reactor were monitored continuously. The present study aimed at the investigation of the abundance of acetogens and total cell numbers and the microbial methanogenic community as derived from PCR-dHPLC analysis in order to put it into context with the determined abiotic parameters. An influence of substrate quantity on the efficiency of the anaerobic digestion process was found as well as a shift from a hydrogenotrophic in times of good reactor performance towards an acetoclastic dominated methanogenic community in times of reduced reactor performance. After the change in substrate conditions it took the methano-archaeal community about 5-6 weeks to be affected but then changes occurred quickly.

  18. Horse manure as feedstock for anaerobic digestion.

    Science.gov (United States)

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible.

  19. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations

    KAUST Repository

    Xiong, Yanghui

    2017-04-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  20. Relationship between microbial activity and microbial community structure in six full-scale anaerobic digesters

    NARCIS (Netherlands)

    Regueiro, L.; Veiga, P.; Figueroa, M.; Alonso-Gutierrez, J.; Stams, A.J.M.; Lema, J.M.; Carballa, M.

    2012-01-01

    High activity levels and balanced anaerobic microbial communities are necessary to attain proper anaerobic digestion performance. Therefore, this work was focused on the kinetic performance and the microbial community structure of six full-scale anaerobic digesters and one lab-scale co-digester. Hyd

  1. Prospects of Anaerobic Digestion Technology in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

  2. 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.

  3. Improved anaerobic digestion performance and biogas production from poultry litter after lowering its nitrogen content.

    Science.gov (United States)

    Markou, Giorgos

    2015-11-01

    Poultry litter (PL) was pre-treated in order to reduce its nitrogen content and to increase the C/N ratio. The pre-treatment consisted of a first anaerobiosis phase of about 60days in order to accumulate ammonia nitrogen, followed by an ammonia stripping phase by heating the substrate at 80°C for 24h. The digestion was performed with PL and pre-treated PL (TPL) after ammonia stripping as mono-substrate under four total solids loads, i.e. 5%, 10%, 15% and 20%. The TPL after ammonia stripping displayed lower ammonia (62-73%) and VFA (41-65%) concentrations compared to digesters with raw PL, while bio-methane yield increased about 8-124%. Bio-methane yields in the series with TPL after ammonia stripping were about 193, 196, 215 and 147 [Formula: see text] /kgCOD, based on the COD added, for 5%, 10%, 15% and 20% TS load, respectively. The results indicate that lowering nitrogen content using the suggested process improves bio-methane yields significantly. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Anaerobic Digestion: Mass Balances and Products

    DEFF Research Database (Denmark)

    Møller, Jacob; Christensen, Thomas Højlund; Jansen, Jes la Cour

    2011-01-01

    While the basic processes involved in anaerobic digestion of waste are described in Chapter 9.4 and the main digestion technologies are presented in Chapter 9.5, this chapter focuses on mass balances, gas production and energy aspects, environmental emissions and unit process inventories. Underst......While the basic processes involved in anaerobic digestion of waste are described in Chapter 9.4 and the main digestion technologies are presented in Chapter 9.5, this chapter focuses on mass balances, gas production and energy aspects, environmental emissions and unit process inventories....... Understanding these issues and being able to account for them is a prerequisite in digestion engineering and for establishing and running a successful anaerobic digestion facility. Of specific importance is the final use of the digestate. Use in agriculture as a fertilizer is described in Chapter 9.10 and use...

  6. 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.

  7. Comparative performance and microbial community of single-phase and two-phase anaerobic systems co-digesting cassava pulp and pig manure

    DEFF Research Database (Denmark)

    Panichnumsin, P.; Ahring, B.K.; Nopharatana, A.

    2010-01-01

    In this study, we illustrated the performance and microbial community of single- and two-phase systems anaerobically co-digesting cassava pulp and pig manure. The results showed that the volatile solid reduction and biogas productivity of two-phase CSTR were 66 ± 4% and 2000 ± 210 ml l-1 d-1, whi...

  8. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Carlos, E-mail: carllosmendez@gmail.com; Esquerre, Karla, E-mail: karlaesquerre@ufba.br; Matos Queiroz, Luciano, E-mail: lmqueiroz@ufba.br

    2015-01-15

    Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

  9. Microbial community structure and performance of an anaerobic reactor digesting cassava pulp and pig manure.

    Science.gov (United States)

    Panichnumsin, P; Ahring, B; Nopharatana, A; Chaiprasert, P

    2012-01-01

    Microbial community dynamics in response to changes in substrate types (i.e. pig manure (PM), cassava pulp (CP) and mixtures of PM and CP) were investigated in an anaerobic continuously stirred tank reactor (CSTR). Molecular identification of bacterial and archaeal domains were performed, using a 16S rDNA clone library with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) screening and phylogenetic analysis. Analysis of bacterial clone libraries revealed that the differences in the community structure corresponded to the substrate types. However, the Bacteroidetes were the most abundant group in all substrates, followed by the Clostridia. With pure PM, the dominant bacterial groups were Bacteroidales, Clostridia and Paludibacter. With a co-substrate, at CP to PM (CP:PM) ratio of 50:50, the sequences analysis revealed the greatest diversity of bacterial communities at class level, and the sequences affiliated with Cytophaga sp. became an exclusive predominant. With CP alone, Bacteroides sp. was the dominant species and this reactor had the lowest diversity of bacteria. Archaea observed in the CSTR fed with all substrate types were Methanosaeta sp., Methanosaeta concilii and Methanospirillum hungatei. Among the Archaea, Methanosaeta sp. was the exclusive predominant. The relative distribution of Archaea also changed regarding to the substrate types.

  10. Fate of Trace Metals in Anaerobic Digestion.

    Science.gov (United States)

    Fermoso, F G; van Hullebusch, E D; Guibaud, G; Collins, G; Svensson, B H; Carliell-Marquet, C; Vink, J P M; Esposito, G; Frunzo, L

    2015-01-01

    A challenging, and largely uncharted, area of research in the field of anaerobic digestion science and technology is in understanding the roles of trace metals in enabling biogas production. This is a major knowledge gap and a multifaceted problem involving metal chemistry; physical interactions of metal and solids; microbiology; and technology optimization. Moreover, the fate of trace metals, and the chemical speciation and transport of trace metals in environments--often agricultural lands receiving discharge waters from anaerobic digestion processes--simultaneously represents challenges for environmental protection and opportunities to close process loops in anaerobic digestion.

  11. Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, F.E. [VFA Services Ltd., Herts (United Kingdom)

    1996-01-01

    This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

  12. Modeling flow inside an anaerobic digester by CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Alexandra Martinez; Jimenez, P. Amparo Lopez [Departmento do Ingenieria Hidralica y Medio Ambiente, Universitat Politecnica de Valencia, Camino de Vera S/N 46022 (Spain); Martinez, Tatiana Montoya; Monanana, Vincente Fajardo [Grupo Aquas de Valencia. Avenida Marques del Turia 19 46005 Valencia (Spain)

    2011-07-01

    Anaerobic processes are used to treat high strength organic wastewater as well as for the treatment of primary and secondary sludge from conventional wastewater treatment plants. In these processes, heterotrophic microorganisms convert biodegradable organic matter to methane and carbon dioxide in the absence of dissolved oxygen and nitrate. Some of the most important aspects of the design of anaerobic digesters are related to hydraulic considerations. In spite of its important role in performance, hydraulics of flow inside digesters has not been quantified or adequately characterized. In this contribution a three-dimensional steady-state computational fluid dynamics (CFD) simulation has been performed for a particular anaerobic digester, in order to visualize the flow patterns. Flow and velocities profiles have been represented inside the digester to identify possible dead zones or stratifications. The geometry of a real digester installed in Valencia Waste Water Treatment Plant (located in Quart-Benager, Valencia, Spain) has been used in order to consider the proposed methodology.

  13. Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

    Science.gov (United States)

    Carnegie, John W., Ed.

    This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

  14. Anaerobic digestion foaming causes – A review

    OpenAIRE

    Ganidi, Nafsika; Tyrrel, Sean F.; Cartmell, Elise

    2009-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water companies due to significant impacts on process efficiency and operational costs. Several foaming causes have been identified over the past few years by researchers. However, the supporting experimental information is limited and in some cases absent. The present report aims to provide a detailed review of the current anaerobic digestion foaming proble...

  15. Comparison of start-up strategies and process performance during semi-continuous anaerobic digestion of sugarcane filter cake co-digested with bagasse.

    Science.gov (United States)

    Janke, Leandro; Leite, Athaydes F; Nikolausz, Marcell; Radetski, Claudemir M; Nelles, Michael; Stinner, Walter

    2016-02-01

    The anaerobic digestion of sugarcane filter cake and the option of co-digestion with bagasse were investigated in a semi-continuous feeding regime to assess the main parameters used for large-scale process designing. Moreover, fresh cattle manure was considered as alternative inoculum for the start-up of biogas reactors in cases where digestate from a biogas plant would not be available in remote rural areas. Experiments were carried out in 6 lab-scale semi-continuous stirred-tank reactors at mesophilic conditions (38±1°C) while the main anaerobic digestion process parameters monitored. Fresh cattle manure demonstrated to be appropriate for the start-up process. However, an acclimation period was required due to the high initial volatile fatty acids concentration (8.5gL(-1)). Regardless the mono-digestion of filter cake presented 50% higher biogas yield (480mLgVS(-1)) than co-digestion with bagasse (320mLgVS(-1)) during steady state conditions. A large-scale co-digestion system would produce 58% more biogas (1008m(3)h(-1)) than mono-digestion of filter cake (634m(3)h(-1)) due to its higher biomass availability for biogas conversion. Considering that the biogas production rate was the technical parameter that displayed the most relevant differences between the analyzed substrate options (0.99-1.45m(3)biogasm(3)d(-1)). The decision of which substrate option should be implemented in practice would be mainly driven by the available construction techniques, since economically efficient tanks could compensate the lower biogas production rate of co-digestion option.

  16. Oxygen Effects in Anaerobic Digestion - II

    Directory of Open Access Journals (Sweden)

    Deshai Botheju

    2010-04-01

    Full Text Available Standard models describing bio-gasification using anaerobic digestion do not include necessary processes to describe digester dynamics under the conditions of oxygen presence. Limited oxygenation in anaerobic digestion can sometimes be beneficial. The oxygen effects included anaerobic digestion model, ADM 1-Ox, was simulated against experimental data obtained from laboratory scale anaerobic digesters operated under different oxygenation conditions. ADM 1-Ox predictions are generally in good agreement with the trends of the experimental data. ADM 1-Ox simulations suggest the existence of an optimum oxygenation level corresponding to a peak methane yield. The positive impact of oxygenation on methane yield is more pronounced at conditions characterized by low hydrolysis rate coefficients (slowly degradable feed and low biomass concentrations. The optimum oxygenation point moves towards zero when the hydrolysis rate coefficient and the biomass concentration increase. Accordingly, the impact of oxygenation on methane yield can either be positive or negative depending on the digestion system characteristics. The developed ADM 1-Ox model can therefore be a valuable tool for recognizing suitable operating conditions for achieving the maximum benefits from partial aeration in anaerobic digestion.

  17. Using contaminated plants involved in phytoremediation for anaerobic digestion.

    Science.gov (United States)

    Cao, Zewei; Wang, Shengxiao; Wang, Ting; Chang, Zhizhou; Shen, Zhenguo; Chen, Yahua

    2015-01-01

    This study investigated the anaerobic digestion capability of five plants and the effects of copper (Cu) and S,S'-ethylenediaminedisuccinic acid (EDDS, a chelator widely used in chelant-assisted phytoremediation) on biogas production to determine a feasible disposal method for plants used in remediation. The results showed that in addition to Phytolacca americana L., plants such as Zea mays L., Brassica napus L., Elsholtzia splendens Nakai ex F. Maekawa, and Oenothera biennis L. performed well in biogas production. Among these, O. biennis required the shortest period to finish anaerobic digestion. Compared to normal plants with low Cu content, the plants used in remediation with increased Cu levels (100 mg kg(-1)) not only promoted anaerobic digestion and required a shorter anaerobic digestion time, but also increased the methane content in biogas. When the Cu content in plants increased to 500, 1000, and 5000 mg kg(-1), the cumulative biogas production decreased by 12.3%, 14.6%, and 41.2%, respectively. Studies also found that EDDS conspicuously restrained biogas production from anaerobic digestion. The results suggest that anaerobic digestion has great potential for the disposal of contaminated plants and may provide a solution for the resource utilization of plants used in remediation.

  18. 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.

  19. 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.

  20. The Influence of Micro-Oxygen Addition on Desulfurization Performance and Microbial Communities during Waste-Activated Sludge Digestion in a Rusty Scrap Iron-Loaded Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    Renjun Ruan

    2017-02-01

    Full Text Available In this study, micro-oxygen was integrated into a rusty scrap iron (RSI-loaded anaerobic digester. Under an optimal RSI dosage of 20 g/L, increasing O2 levels were added stepwise in seven stages in a semi-continuous experiment. Results showed the average methane yield was 306 mL/g COD (chemical oxygen demand, and the hydrogen sulphide (H2S concentration was 1933 ppmv with RSI addition. O2 addition induced the microbial oxidation of sulphide by stimulating sulfur-oxidizing bacteria and chemical corrosion of iron, which promoted the generation of FeS and Fe2S3. In the 6th phase of the semi-continuous test, deep desulfurization was achieved without negatively impacting system performance. Average methane yield was 301.1 mL/g COD, and H2S concentration was 75 ppmv. Sulfur mass balance was described, with 84.0%, 11.90% and 0.21% of sulfur present in solid, liquid and gaseous phases, respectively. The Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE analysis revealed that RSI addition could enrich the diversity of hydrogenotrophic methanogens and iron-reducing bacteria to benefit methanogenesis and organic mineralization, and impoverish the methanotroph (Methylocella silvestris to reduce the consumption of methane. Micro-oxygen supplementation could enhance the diversity of iron-oxidizing bacteria arising from the improvement of Fe(II release rate and enrich the sulphur-oxidising bacteria to achieved desulfurization. These results demonstrated that RSI addition in combination with micro-oxygenation represents a promising method for simultaneously controlling biogas H2S concentration and improving digestion performance.

  1. Robust regulation of anaerobic digestion processes.

    Science.gov (United States)

    Mailleret, L; Bernard, O; Steyer, J P

    2003-01-01

    This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.

  2. Anaerobic digestion of pot-ale

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, F.E.

    1990-12-01

    In the production of whisky, the fermented wash is distilled twice and each bushel of grain yields about 15.5 gallons of pot-ale, 6.0 gallons of spent lees and 2.7 gallons of proof spirit. Disposal of pot-ale, the strong residue from the first distillation, containing all the non-volatile and unfermented components of the wash, will always be difficult. Anaerobic digestion provides a possible option. By destroying most of the biodegradable solids and converting them to biogas, it provides an intermediate effluent which conventional treatment technology can purify to river discharge standards. Pilot-scale trials confirm that pot-ale can be treated by anaerobic digestion. The most severe problems are the high purification efficiencies required to achieve UK river discharge standards and the quality and settling properties of the biological sludges produced. To achieved these standards, the design and operation of the entire treatment chain is dominated by the need to capture and concentrate suspended solids (SS) produced by the biological fermentations. Overall performance targets are 99.95% removal of biological oxygen demand (BOD), 99% removal of ammonia and a surplus sludge production of less than 20% of the incoming flow. (author).

  3. The performance efficiency of bioaugmentation to prevent anaerobic digestion failure from ammonia and propionate inhibition.

    Science.gov (United States)

    Li, Ying; Zhang, Yue; Sun, Yongming; Wu, Shubiao; Kong, Xiaoying; Yuan, Zhenhong; Dong, Renjie

    2017-05-01

    This study aims to investigate the effect of bioaugmentation with enriched methanogenic propionate degrading microbial consortia on propionate fermentation under ammonia stress from total ammonia nitrogen concentration (TAN) of 3.0gNL(-1). Results demonstrated that bioaugmentation could prevent unstable digestion against further deterioration. After 45days of 1dosage (0.3g dry cell weight L(-1)d(-1), DCW L(-1)d(-1)) of bioaugmentation, the average volumetric methane production (VMP), methane recovery rate and propionic acid (HPr) degradation rate was enhanced by 70mLL(-1)d(-1), 21% and 51%, respectively. In contrast, the non-bioaugmentation reactor almost failed. Routine addition of a double dosage (0.6g DCW L(-1)d(-1)) of bioaugmentation culture was able to effectively recover the failing digester. The results of FISH suggested that the populations of Methanosaetaceae increased significantly, which could be a main contributor for the positive effect on methane production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Performance and kinetic evaluation of a semi-continuously fed anaerobic digester treating food waste: effect of trace elements on the digester recovery and stability.

    Science.gov (United States)

    Wei, Quanyuan; Zhang, Wanqin; Guo, Jianbin; Wu, Shubiao; Tan, Tianwei; Wang, Fang; Dong, Renjie

    2014-12-01

    This study investigated the effects of trace elements (TEs: Fe, Co, and Ni) on the anaerobic digestion of food waste in laboratory scale semi-continuously fed anaerobic digesters. The digesters were operated for approximately 460 d at organic loading rates (OLRs) ranging from 1.0 to 5.0 g VS L(-1)d(-1) at 37°C. Results showed that methane production was severely inhibited when volatile fatty acids (VFAs) concentration was 30,000 mg L(-1) at OLR of 4.0 g VS L(-1)d(-1) without the addition of TEs. However, the inhibition was gradually decreased and the methane production increased from 0.13 up to 0.44 L g(-1)VS added when the TEs was added. Fe was proved to be the essential element in maintaining the stability of the digester. The conversion coefficient of substrate into biogas (YS/G) was 1.00 and 1.26 gVS removedL(-1) biogas with and without TEs addition, respectively. The estimated biomass yield with feeding TEs (0.06 g VSS g(-1)COD removed) was higher three times than that without TEs (0.02 gVSS g(-1)COD removed).

  5. Influence of applied voltage on the performance of bioelectrochemical anaerobic digestion of sewage sludge and planktonic microbial communities at ambient temperature.

    Science.gov (United States)

    Feng, Qing; Song, Young-Chae; Bae, Byung-Uk

    2016-11-01

    The influence of applied voltage on the bioelectrochemical anaerobic digestion of sewage sludge was studied at ambient temperature (25±2°C). The stability of the bioelectrochemical anaerobic digestion was considerably good in terms of pH, alkalinity and VFAs at 0.3V and 0.5V, but VFA accumulation occurred at 0.7V. The specific methane production rate (370mLCH4/L.d) was the highest at 0.3V, but the methane content (80.6%) in biogas and the methane yield (350mLCH4/gCODr) were higher at 0.5V, significantly better than those of 0.7V. The VS removal efficiency was 64-66% at 0.3V and 0.5V, but only 31% at 0.7V. The dominant species of planktonic microbial communities was Cloacamonas at 0.3V and 0.5V, but the percentage of hydrolytic bacteria species such as Saprospiraceae, Fimbriimonas, and Ottowia pentelensis was much higher at 0.7V. The optimal applied voltage for bioelectrochemical anaerobic digestion was 0.3-0.5V according to digestion performance and planktonic microbial communities.

  6. Modified anaerobic digestion elutriated phased treatment for the anaerobic co-digestion of sewage sludge and food wastewater.

    Science.gov (United States)

    Mo, Kyung; Lee, Wonbae; Kim, Moonil

    2017-02-01

    A modified anaerobic digestion elutriated phased treatment (MADEPT) process was developed for investigating anaerobic co-digestion of sewage sludge and food wastewater. The anaerobic digestion elutriated phased treatment (ADEPT) process is similar to a two-phase system, however, in which the effluent from a methanogenic reactor recycles into an acidogenic reactor to elutriate mainly dissolved organics. Although ADEPT could reduce reactor volume significantly, the unsolubilized solids should be wasted from the system. The MADEPT process combines thermo-alkali solubilization with ADEPT to improve anaerobic performance and to minimize the sludge disposal. It was determined that the optimal volume mixing ratio of sewage sludge and food wastewater was 4 : 1 for the anaerobic co-digestion. The removal efficiencies of total chemical oxygen demand, volatile solids, and volatile suspended solids in the MADEPT process were 73%, 70%, and 64%, respectively. However, those in the ADEPT process were only 48%, 37%, and 40%, respectively, at the same hydraulic retention time (HRT) of 7 days. The gas production of MADEPT was two times higher than that of ADEPT. The thermo-alkali solubilization increased the concentration of dissolved organics so that they could be effectively degraded in a short HRT, implying that MADEPT could improve the performance of ADEPT in anaerobic co-digestion.

  7. University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Koker, John [Univ. of Wisconsin, Oshkosh, WI (United States); Lizotte, Michael [Univ. of Wisconsin, Oshkosh, WI (United States)

    2017-02-08

    The University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility is a demonstration project that supported the first commercial-scale use in the United States of high solids, static pile technology for anaerobic digestion of organic waste to generate biogas for use in generating electricity and heat. The research adds to the understanding of startup, operation and supply chain issues for anaerobic digester technology. Issues and performance were documented for equipment installation and modifications, feedstock availability and quality, weekly loading and unloading of digestion chambers, chemical composition of biogas produced, and energy production. This facility also demonstrated an urban industrial ecology approach to siting such facilities near sewage treatment plants (to capture and use excess biogas generated by the plants) and organic yard waste collection sites (a source of feedstock).

  8. A new approach for concurrently improving performance of South Korean food waste valorization and renewable energy recovery via dry anaerobic digestion under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Nguyen, Dinh Duc; Yeop, Jeong Seong; Choi, Jaehoon; Kim, Sungsu; Chang, Soon Woong; Jeon, Byong-Hun; Guo, Wenshan; Ngo, Huu Hao

    2017-08-01

    Dry semicontinuous anaerobic digestion (AD) of South Korean food waste (FW) under four solid loading rates (SLRs) (2.30-9.21kg total solids (TS)/m(3)day) and at a fixed TS content was compared between two digesters, one each under mesophilic and thermophilic conditions. Biogas production and organic matter reduction in both digesters followed similar trends, increasing with rising SLR. Inhibitor (intermediate products of the anaerobic fermentation process) effects on the digesters' performance were not observed under the studied conditions. In all cases tested, the digesters' best performance was achieved at the SLR of 9.21kg TS/m(3)day, with 74.02% and 80.98% reduction of volatile solids (VS), 0.87 and 0.90m(3) biogas/kg VSremoved, and 0.65 (65% CH4) and 0.73 (60.02% CH4) m(3) biogas/kg VSfed, under mesophilic and thermophilic conditions, respectively. Thermophilic dry AD is recommended for FW treatment in South Korea because it is more efficient and has higher energy recovery potential when compared to mesophilic dry AD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Application of Anaerobic Digestion Model No. 1 for describing anaerobic digestion of grass, maize, green weed silage, and industrial glycerine.

    Science.gov (United States)

    Biernacki, Piotr; Steinigeweg, Sven; Borchert, Axel; Uhlenhut, Frank

    2013-01-01

    Anaerobic digestion of organic waste plays an important role for the development of sustainable energy supply based on renewable resources. For further process optimization of anaerobic digestion, biogas production with the commonly used substrates, grass, maize, and green weed silage, together with industrial glycerine, were analyzed by the Weender analysis/van Soest method, and a simulation study was performed, based on the International Water Association's (IWA) Anaerobic Digestion Model No. 1 (ADM1). The simplex algorithm was applied to optimize kinetic constants for disintegration and hydrolysis steps for all examined substrates. Consequently, new parameters were determined for each evaluated substrate, tested against experimental cumulative biogas production results, and assessed against ADM1 default values for disintegration and hydrolysis kinetic constants, where the ADM1 values for mesophilic high rate and ADM1 values for solids were used. Results of the optimization lead to a precise prediction of the kinetics of anaerobic degradation of complex substrates.

  10. Multivariate monitoring of anaerobic co-digestion

    DEFF Research Database (Denmark)

    Madsen, Michael; Holm-Nielsen, Jens Bo

    fertiliser and renewable energy. Meanwhile, in order for the biogas sector to become a significant player in the energy supply chain, the anaerobic digestion process has to be controlled to a greater extent than what is implemented as state-of-the-art today. Through application of the philosophy behind......Anaerobic digestion processes for production of renewable energy in the form of biogas, and in the future hydrogen, are becoming increasingly important worldwide. Sustainable solutions for renewable energy production systems are given high political priority, amongst other things due to global...... warming and environmental concerns. Anaerobic digestion applied in agriculture can simultaneously convert heterogeneous biomasses and wastes from the primary agricultural sector and from the bio processing industries, for instance food processing, pharma, and biofuel production, into valuable organic...

  11. 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.

  12. The Effect of Enzyme Addition on Anaerobic Digestion of Jose Tall Wheat Grass

    Science.gov (United States)

    The effects of the addition of enzyme products containing cellulase, hemicellulase, and Beta-glucosidase to anaerobic digestion systems were studied. Anaerobic digestion tests were performed using batch reactors operated at 35°C. The application of enzyme products in three digestion configurations w...

  13. Anaerobic digestion of manure and mixture of manure with lipids: biogas reactor performance and microbial community analysis

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana; Dabrowski, Slawomir; Ahring, Birgitte Kiær

    2003-01-01

    the activity of acetotrophic methanogens was uniformly distributed in all fractions. When digesting manure and lipids, an enhanced methanogenesis was detected both for particles > 200 mum and the 50-200 mum fraction. The molecular methods -temperature gradient gel electrophoresis (TGGE), cloning library......Anaerobic digestion of cattle manure and a mixture of cattle manure with glycerol trioleate (GTO) was studied in lab-scale, continuously stirred tank reactors (CSTR) operated at 37degreesC. The reactor. codigesting manure and lipids exhibited a significantly higher specific methane yield...... and a higher removal of VS than the reactor treating manure. Microbial population analysis done by cultivation - most probable number (MPN) test and specific methanogenic activity (SMA) measurement, revealed higher MPN and increased SMA of methanogenic populations of biomass from the reactor codigesting manure...

  14. 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.

  15. Improving Project Outcomes and Growing the Anaerobic Digestion Industy Report

    Science.gov (United States)

    Anaerobic digestion ombudsmen assist with project development, ensure the long-term sustainability of projects, and help advance the industry. This report explores the benefits of anaerobic digestion ombudsmen and provides guidance for implementing them.

  16. Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure.

    Science.gov (United States)

    Timmerman, Maikel; Schuman, Els; van Eekert, Miriam; van Riel, Johan

    2015-01-01

    Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on manure (>90%); however, the methane yields of manure are less compared to coproducts, which is one of the reasons for manure-based biogas plants often being economically non-viable. Therefore, it is essential to begin increasing the efficiency of these biogas plants. This study investigated the effect of decreasing retention time and introducing a moderate amount of glycerin on the biogas production as methods to improve efficiency. An experiment has been conducted with two different manure types in four biogas reactors. The results of the study demonstrated that, first, it was possible to decrease the retention time to 10-15 days; however, the effect on biogas production varied per manure type. Secondly, the biogas production almost triples at a retention time of 15.6 days with an addition of 4% glycerin. The relative production-enhancing effect of glycerin did not vary significantly with both manure types. However, the absolute production-enhancing effect of glycerin differed per manure type since the biogas production per gram VS differed per manure type. Thirdly, the positive effect of the glycerin input declines with shorter retention times. Therefore, the effect of glycerin addition depends on the manure type and retention time.

  17. The IWA Anaerobic Digestion Model No 1 (ADM1)

    NARCIS (Netherlands)

    Batstone, D.J.; Keller, J.; Angelidaki, I.; Kalyuzhnyi, S.V.; Pavalostathis, S.G.; Rozzi, A.; Sanders, W.T.M.; Siegrist, H.; Vavilin, V.A.

    2002-01-01

    The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as

  18. The IWA Anaerobic digestion model no 1. (ADM1)

    DEFF Research Database (Denmark)

    Batstone, Damien J.; Keller, J.; Angelidaki, Irini

    2002-01-01

    The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well...

  19. Anaerobic digestion in sustainable biomass chains

    NARCIS (Netherlands)

    Pabon Pereira, C.P.

    2009-01-01

    This thesis evaluates the potential contribution of anaerobic digestion (AD) to the sustainability of biomass chains. Results provide insights in the technological potential to recover energy and valuable by-products from energy crops and residues, and evaluate biomass cascades involving AD technolo

  20. Anaerobic Digestion in a Flooded Densified Leachbed

    Science.gov (United States)

    Chynoweth, David P.; Teixeira, Arthur A.; Owens, John M.; Haley, Patrick J.

    2009-01-01

    A document discusses the adaptation of a patented biomass-digesting process, denoted sequential batch anaerobic composting (SEBAC), to recycling of wastes aboard a spacecraft. In SEBAC, high-solids-content biomass wastes are converted into methane, carbon dioxide, and compost.

  1. Anaerobic hydrolysis during digestion of complex substrates

    NARCIS (Netherlands)

    Sanders, W.T.M.

    2001-01-01

    Complex waste(water) such as, raw sewage, dairy wastewater, slaughterhouse wastewater, fish processing wastewater, primary sludge and the organic fraction of municipal solid waste have been proven to be degradable under anaerobic conditions. However, during the digestion process the conversion of th

  2. Instrumentation and Control in Anaerobic Digestion

    DEFF Research Database (Denmark)

    Anaerobic digestion is a multistep process, and is most applied to solids destruction and wastewater treatment for energy production. Despite wide application, and long-term industrial proof of application, some industries are still reluctant to apply this technology. One of the classical reasons...... benchmark. There has therefore been, overall, a quantum advance in application and sophistication of instrumentation and control in anaerobic digestion, and it is an effective option for improved process loading rate and conversion efficiency....... are still a limitation, but this is being partly addressed by the increased complexity of digestion processes. Methods for control benchmarking have also been improved, as there is now an industry standard model (the IWA ADM1), and this is being applied in an improved whole wastewater treatment plant...

  3. Evaluation of A Novel Split-Feeding Anaerobic/Oxic Baffled Reactor (A/OBR) For Foodwaste Anaerobic Digestate: Performance, Modeling and Bacterial Community

    Science.gov (United States)

    Wang, Shaojie; Peng, Liyu; Jiang, Yixin; Gikas, Petros; Zhu, Baoning; Su, Haijia

    2016-10-01

    To enhance the treatment efficiency from an anaerobic digester, a novel six-compartment anaerobic/oxic baffled reactor (A/OBR) was employed. Two kinds of split-feeding A/OBRs R2 and R3, with influent fed in the 1st, 3rd and 5th compartment of the reactor simultaneously at the respective ratios of 6:3:1 and 6:2:2, were compared with the regular-feeding reactor R1 when all influent was fed in the 1st compartment (control). Three aspects, the COD removal, the hydraulic characteristics and the bacterial community, were systematically investigated, compared and evaluated. The results indicated that R2 and R3 had similar tolerance to loading shock, but the R2 had the highest COD removal of 91.6% with a final effluent of 345 mg/L. The mixing patterns in both split-feeding reactors were intermediate between plug-flow and completely-mixed, with dead spaces between 8.17% and 8.35% compared with a 31.9% dead space in R1. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that the split-feeding strategy provided a higher bacterial diversity and more stable bacterial community than that in the regular-feeding strategy. Further analysis indicated that Firmicutes, Bacteroidetes, and Proteobacteria were the dominant bacteria, among which Firmicutes and Bacteroidetes might be responsible for organic matter degradation and Proteobacteria for nitrification and denitrification.

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

    Science.gov (United States)

    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.

  5. The challenges of anaerobic digestion and the role of biochar in optimizing anaerobic digestion.

    Science.gov (United States)

    Fagbohungbe, Michael O; Herbert, Ben M J; Hurst, Lois; Ibeto, Cynthia N; Li, Hong; Usmani, Shams Q; Semple, Kirk T

    2017-03-01

    Biochar, like most other adsorbents, is a carbonaceous material, which is formed from the combustion of plant materials, in low-zero oxygen conditions and results in a material, which has the capacity to sorb chemicals onto its surfaces. Currently, research is being carried out to investigate the relevance of biochar in improving the soil ecosystem, digestate quality and most recently the anaerobic digestion process. Anaerobic digestion (AD) of organic substrates provides both a sustainable source of energy and a digestate with the potential to enhance plant growth and soil health. In order to ensure that these benefits are realised, the anaerobic digestion system must be optimized for process stability and high nutrient retention capacity in the digestate produced. Substrate-induced inhibition is a major issue, which can disrupt the stable functioning of the AD system reducing microbial breakdown of the organic waste and formation of methane, which in turn reduces energy output. Likewise, the spreading of digestate on land can often result in nutrient loss, surface runoff and leaching. This review will examine substrate inhibition and their impact on anaerobic digestion, nutrient leaching and their environmental implications, the properties and functionality of biochar material in counteracting these challenges. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Anaerobic digestion of sludge differing in inorganic solids content: performance comparison and the effect of inorganic suspended solids content on degradation.

    Science.gov (United States)

    Duan, Nina; Dai, Xiaohu; Dong, Bin; Dai, Lingling

    2016-11-01

    High inorganic suspended solids (ISS) content of sludge in many areas (especially with combined sewage systems) results in low VS/TS (volatile solids, VS; total solids, TS) levels and raises concerns about its effect on anaerobic digestion. The performances of sludge anaerobic digestion with different feeding VS/TS levels as well as the effect of ISS content on the anaerobic degradation process were investigated in completely stirred tank reactors by semi-continuous and batch experiments. In semi-continuous experiment with sludge at VS/TS of 61.4%, 45.0, 30.0% and 15.0%, biogas yield, VS reduction and methane content decreased logarithmically with the feeding VS/TS decreasing; slightly higher volatile fatty acid concentration was observed at VS/TS 15%. Results of the batch experiments suggested that acetogenesis and methanogenesis are obviously affected by high ISS addition, while hydrolysis is less affected. The retardment of substrate conversion rate is probably attributed to decreased mass transfer efficiency at high ISS content.

  7. An innovative bioelectrochemical-anaerobic digestion-coupled system for in-situ ammonia recovery and biogas enhancement: process performance and microbial ecology

    OpenAIRE

    Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    Ammonia (NH4+/NH3) inhibition during anaerobic digestion process is one of the most frequent problems existing in biogas plants, resulting in unstable process and reduced biogas production. In this study, we developed a novel hybrid system, consisted of a submersed microbial resource recovery cell (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production. In batch experiment, the ammonia c...

  8. Improvement of anaerobic digestion of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Dohanyos, Michael; Zabranska, Jana; Kutil, Josef; Jenicek, Pavel

    2003-07-01

    Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of process conditions is frequently used pretreatment of input sludge and increase of process temperature. Thermophilic process brings a higher solids reduction and biogas production, the high resistance to foaming, no problems with odour, the higher effect of destroying pathogens and the improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in lysate centrifuge was proved in full-scale conditions causing increase of biogas production. The rapid thermal conditioning of digested sludge is acceptable method of particulate matter disintegration and solubilization. (author)

  9. Electrochemical monitoring of ammonia during anaerobic digestion

    DEFF Research Database (Denmark)

    Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

    Ammonia is known as key inhibitor to methanogens in anaerobic digestion (AD) process. It’s of importance to develop efficient tool for ammonia monitoring. In this study, an electrolysis cell (EC) coupled with a complete nitrification reactor was developed as sensor for real time and online......-rich digesters. It was observed that the initial transient currents (0 min) were linearly corresponding to the ammonia levels (from 0 to 95.75 mg/L NH4+-N, R2 = 0.9673). Finally, this new sensor was tested with real AD effluent and the results showed no significant difference with that measured by conventional...

  10. Numerical analysis of the anaerobic co-digestion of the organic fraction from municipal solid waste and wastewater: prediction of the possible performances at Olmeto plant in Perugia (Italy).

    Science.gov (United States)

    Viotti, Paolo; Di Genova, Paolo; Falcioli, Francesca

    2004-04-01

    Anaerobic digestion is mainly used for sewage sludge stabilization and for treatment of waste that has a high organic content. It also represents a powerful method for obtaining energy by means of natural gas production. Co-digestion particularly combines different organic substrates to generate a homogeneous mixture as input to the anaerobic reactor in order to increase process performance. Reactions kinetics and knowledge of process analysis represent the keys for good planning and correct management. In this paper a model to simulate the main reactions involved in anaerobic co-digestion is presented. The model was created to analyse the possible performance of the treatment plant in Olmeto, Marsciano (Perugia) in Italy. The plant is still in an experimental phase with regard to the co-digestion process and numerical simulations represent a useful tool during development of the correct management procedures for the operational phase and a good methodoly for addressing further pilot plant experiments.

  11. 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.

  12. Comparative performance and microbial community of single-phase and two-phase anaerobic systems co-digesting cassava pulp and pig manure

    DEFF Research Database (Denmark)

    Panichnumsin, P.; Ahring, B.K.; Nopharatana, A.

    2010-01-01

    In this study, we illustrated the performance and microbial community of single- and two-phase systems anaerobically co-digesting cassava pulp and pig manure. The results showed that the volatile solid reduction and biogas productivity of two-phase CSTR were 66 ± 4% and 2000 ± 210 ml l-1 d-1, while...... predominant in both digesters while the relative abundance of Methanosaeta sp. and Methanospirillum hungatei differed between the two systems......., followed by the Clostridia in singlephase CSTR. In hydrolysis/acidification reactor of two-phase system, the bacteria within the phylum Firmicutes, especially Clostridium, Eubacteriaceae and Lactobacillus were the dominant phylogenetic groups. Among the Archaea, Methanosaeta sp. was the exclusive...

  13. 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 ...

  14. 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.

  15. Improvement of anaerobic digestion control from urban sludges; Mejora del control de la digestion anaerobia de fangos urbanos

    Energy Technology Data Exchange (ETDEWEB)

    Minguez Gabina, R.

    2002-07-01

    Due to its many advantages, the anaerobic digestion is a widespread choice in our water treatment plants. Furthermore, the companies demand an optimization of the control of the process. Until today, the practice of the operation has been made modifying the conditions of the digester by controlling the outlet parameters of the digestion, so that a delay in the application of the corrections is enough to decrease the performance. The investigation concludes that the most secure way to drive an anaerobic digester is to mange a strict control of the inlet parameters into digestion process. (Author)

  16. 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.

  17. 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.

  18. Anaerobic sludge digestion with a biocatalytic additive

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

  19. Improvement of anaerobic digestion performance by continuous nitrogen removal with a membrane contactor treating a substrate rich in ammonia and sulfide.

    Science.gov (United States)

    Lauterböck, B; Nikolausz, M; Lv, Z; Baumgartner, M; Liebhard, G; Fuchs, W

    2014-04-01

    The effect of reduced ammonia levels on anaerobic digestion was investigated. Two reactors were fed with slaughterhouse waste, one with a hollow fiber membrane contractor for ammonia removal and one without. Different organic loading rates (OLR) and free ammonia and sulfide concentrations were investigated. In the reactor with the membrane contactor, the NH4-N concentration was reduced threefold. At a moderate OLR (3.1 kg chemical oxygen demand - COD/m(3)/d), this reactor performed significantly better than the reference reactor. At high OLR (4.2 kg COD/m(3)/d), the reference reactor almost stopped producing methane (0.01 Nl/gCOD). The membrane reactor also showed a stable process with a methane yield of 0.23 Nl/g COD was achieved. Both reactors had predominantly a hydrogenotrophic microbial consortium, however in the membrane reactor the genus Methanosaeta (acetoclastic) was also detected. In general, all relevant parameters and the methanogenic consortium indicated improved anaerobic digestion of the reactor with the membrane.

  20. Large eddy simulation of mechanical mixing in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin

    2012-03-01

    A comprehensive study of anaerobic digestion requires an advanced turbulence model technique to accurately predict mixing flow patterns because the digestion process that involves mass transfer between anaerobes and their substrates is primarily dependent on detailed information about the fine structure of turbulence in the digesters. This study presents a large eddy simulation (LES) of mechanical agitation of non-Newtonian fluids in anaerobic digesters, in which the sliding mesh method is used to characterize the impeller rotation. The three subgrid scale (SGS) models investigated are: (i) Smagorinsky-Lilly model, (ii) wall-adapting local eddy-viscosity model, and (iii) kinetic energy transport (KET) model. The simulation results show that the three SGS models produce very similar flow fields. A comparison of the simulated and measured axial velocities indicates that the LES profile shapes are in general agreement with the experimental data but they differ markedly in velocity magnitudes. A check of impeller power and flow numbers demonstrates that all the SGS models give excellent predictions, with the KET model performing the best. Moreover, the performance of six Reynolds-averaged Navier-Stokes turbulence models are assessed and compared with the LES results.

  1. Anaerobic digestion of slaughterhouse by-products

    Energy Technology Data Exchange (ETDEWEB)

    Hejnfelt, Anette; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DTU, Building 113, DK-2800 Kgs. Lyngby (Denmark)

    2009-08-15

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 C and for some experiments also at 37 C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm{sup 3} kg{sup -1} respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm{sup -3} and 7 g N dm{sup -3} respectively. Pretreatment (pasteurization: 70 C, sterilization: 133 C), and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 C showed 40% higher methane production compared to digestion of manure alone. (author)

  2. Anaerobic digestion of slaughterhouse by-products

    DEFF Research Database (Denmark)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497,487, 561, 582, 575, 359, 619 dm(3) kg(-1) respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions......Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 degrees C and for some experiments also at 37 degrees C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone...

  3. Anaerobic digestion of straw and corn stover: The effect of biological process optimization and pre-treatment on total bio-methane yield and energy performance.

    Science.gov (United States)

    Croce, Serena; Wei, Qiao; D'Imporzano, Giuliana; Dong, Renjie; Adani, Fabrizio

    2016-12-01

    Anaerobic digestion (AD) is a useful method for producing renewable energy/biofuel. Today, biogas production uses a large amount of energy crops (EC), with the effect of increasing AD costs and creating conflict between food/feed vs. energy use. A partial solution to this might be the substitution of EC with agricultural wastes, e.g. straw. Straw and corn stover are widely available in the world and approximately 1600millionMgyear(-1) of these substrates are available. Straw can be useful used for biogas production but its characteristics limit its performance so that sometimes the energetic balance can be negative. In this review, the limits for the conversion of this substrate into biogas were investigated and solutions/proposals for getting higher straw biogas production performance are reported. In addition, energetic balances for untreated and pre-treated substrates are reported, giving indicative evaluations of the sustainability of straw and corn stover use for biogas production.

  4. Investigation of Anaerobic Digestion Alternatives for Henriksdal's WWTP

    OpenAIRE

    Jeppsson, Ulf

    2007-01-01

    On the request of Dr Daniel Hellström (Stockholm Water AB), IEA was asked to perform a preliminary investigation of two alternatives for anaerobic digestion operation at Henriksdal’s WWTP in Stockholm, Sweden. The system should be analysed based on parallel or series operation of two existing AD reactors. Moreover, the input load should be based on the current situation and a future scenario (estimated 10 years ahead).

  5. Optimization of solid state anaerobic digestion of the OFMSW by digestate recirculation: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Michele, Pognani, E-mail: michele.pognani@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Giuliana, D’Imporzano, E-mail: giuliana.dimporzano@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi (Italy); Carlo, Minetti, E-mail: carlo.minetti@a2a.eu [Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia (Italy); Sergio, Scotti, E-mail: sergio.scotti@a2a.eu [Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia (Italy); Fabrizio, Adani, E-mail: farbrizio.adani@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi (Italy)

    2015-01-15

    Highlights: • Solid State Anaerobic Digestion (SSAD) of OFMSW can be optimized by irrigation with digestate. • Digestate spreading allows keeping optimal process parameters and high hydrolysis rate. • The 18.4% of CH{sub 4} was produced in the reactor, leaving the 49.7% in the percolate. • Successive CSTR feed with percolate shows a biogas enriched in methane (more than 80%). • The proposed process allow producing the 68% of OFMSW potential CH{sub 4}, getting high quality organic amendment. - Abstract: Dry anaerobic digestion (AD) of OFMSW was optimized in order to produce biogas avoiding the use of solid inoculum. Doing so the dry AD was performed irrigating the solid waste with liquid digestate (flow rate of 1:1.18–1:0.9 w/w waste/digestate; 21 d of hydraulic retention time – HRT) in order to remove fermentation products inhibiting AD process. Results indicated that a high hydrolysis rate of organic matter (OM) and partial biogas production were obtained directly during the dry AD. Hydrolysate OM was removed from digester by the percolate flow and it was subsequently used to feed a liquid anaerobic digester. During dry AD a total loss of 36.9% of total solids was recorded. Methane balance indicated that 18.4% of potential methane can be produced during dry AD and 49.7% by the percolate. Nevertheless results obtained for liquid AD digestion indicated that only 20.4% and 25.7% of potential producible methane was generated by adopting 15 and 20 days of HRT, probably due to the AD inhibition due to high presence of toxic ammonia forms in the liquid medium.

  6. ANAEROBIC DIGESTION AND THE DENITRIFICATION IN UASB REACTOR

    Directory of Open Access Journals (Sweden)

    José Tavares de Sousa

    2008-01-01

    Full Text Available The environmental conditions in Brazil have been contributing to the development of anaerobic systems in the treatment of wastewaters, especially UASB - Upflow Anaerobic Sludge Blanket reactors. The classic biological process for removal of nutrients uses three reactors - Bardenpho System, therefore, this work intends an alternative system, where the anaerobic digestion and the denitrification happen in the same reactor reducing the number of reactors for two. The experimental system was constituted by two units: first one was a nitrification reactor with 35 L volume and 15 d of sludge age. This system was fed with raw sanitary waste. Second unit was an UASB, with 7.8 L and 6 h of hydraulic detention time, fed with ¾ of effluent nitrification reactor and ¼ of raw sanitary waste. This work had as objective to evaluate the performance of the UASB reactor. In terms of removal efficiency, of bath COD and nitrogen, it was verified that the anaerobic digestion process was not affected. The removal efficiency of organic material expressed in COD was 71%, performance already expected for a reactor of this type. It was also observed that the denitrification process happened; the removal nitrate efficiency was 90%. Therefore, the denitrification process in reactor UASB is viable.

  7. A fuzzy logic approach to control anaerobic digestion

    NARCIS (Netherlands)

    Domnanovich, A.M.; Strik, D.P.B.T.B.; Pfeiffer, B.; Karlovits, M.; Zani, L.; Braun, R.; Holubar, P.

    2003-01-01

    One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the nex

  8. A fuzzy logic approach to control anaerobic digestion

    NARCIS (Netherlands)

    Domnanovich, A.M.; Strik, D.P.B.T.B.; Pfeiffer, B.; Karlovits, M.; Zani, L.; Braun, R.; Holubar, P.

    2003-01-01

    One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the nex

  9. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    Science.gov (United States)

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  10. A fuzzy logic approach to control anaerobic digestion

    NARCIS (Netherlands)

    Domnanovich, A.M.; Strik, D.P.B.T.B.; Pfeiffer, B.; Karlovits, M.; Zani, L.; Braun, R.; Holubar, P.

    2003-01-01

    One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the

  11. Winery and distillery wastewater treatment by anaerobic digestion.

    Science.gov (United States)

    Moletta, R

    2005-01-01

    Anaerobic digestion is widely used for wastewater treatment, especially in the food industries. Generally after the anaerobic treatment there is an aerobic post-treatment in order to return the treated water to nature. Several technologies are applied for winery wastewater treatment. They are using free cells or flocs (anaerobic contact digesters, anaerobic sequencing batch reactors and anaerobic lagoons), anaerobic granules (Upflow Anaerobic Sludge Blanket--UASB), or biofilms on fixed support (anaerobic filter) or on mobile support as with the fluidised bed. Some technologies include two strategies, e.g. a sludge bed with anaerobic filter as in the hybrid digester. With winery wastewaters (as for vinasses from distilleries) the removal yield for anaerobic digestion is very high, up to 90-95% COD removal. The organic loads are between 5 and 15 kgCOD/m3 of digester/day. The biogas production is between 400 and 600 L per kg COD removed with 60 to 70% methane content. For anaerobic and aerobic post-treatment of vinasses in the Cognac region, REVICO company has 99.7% COD removal and the cost is 0.52 Euro/m3 of vinasses.

  12. Anaerobic Digestion Modeling: from One to Several Bacterial Populations

    Directory of Open Access Journals (Sweden)

    Iván D. Ramírez-Rivas

    2013-11-01

    Full Text Available Anaerobic digestion systems are complex processes that unfortunately often suffer from instability causing digester failure. In order to be able to design, optimizing and operate efficiently anaerobic digestion systems, appropriate control strategies need to be designed. Such strategies require, in general, the development of mathematical models. The anaerobic digestion process comprises a complex network of sequential and parallel reactions of biochemical and physicochemical nature. Usually, such reactions contain a particular step, the so called rate-limiting step which, being the slowest, limits the reaction rate of the overall process. The first attempts for modeling anaerobic digestion led to models describing only the limiting step. However, over a wide range of operating conditions, the limiting step is not always the same. It may depend on wastewater characteristics, hydraulic loading, temperature, etc. It is apparent that the "limiting step hypothesis" leads to simple and readily usable models. Such models, however, do not describe very well the digester behavior, especially under transient operating conditions. This work reviews the current state-of-the-art in anaerobic digestion modeling. We give a brief description of the key anaerobic digestion models that have been developed so far for describing biomass growth systems, including the International Water Association’s Anaerobic Digestion Model 1 (ADM1 and we identify the areas that require further research endeavors.

  13. Foaming phenomenon in bench-scale anaerobic digesters.

    Science.gov (United States)

    Siebels, Amanda M; Long, Sharon C

    2013-04-01

    The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

  14. Biogas production performance of mesophilic and thermophilic anaerobic co-digestion with fat, oil, and grease in semi-continuous flow digesters: effects of temperature, hydraulic retention time, and organic loading rate.

    Science.gov (United States)

    Li, C; Champagne, P; Anderson, B C

    2013-01-01

    Anaerobic co-digestions with fat, oil, and grease (FOG) were investigated in semi-continuous flow digesters under various operating conditions. The effects of hydraulic retention times (HRTs) of 12 and 24 days, organic loading rates (OLRs) between 1.19 and 8.97 gTVS/Ld, and digestion temperatures of 37 degrees C and 55 degrees C on biogas production were evaluated. It was proposed that, compared to anaerobic digestion with wastewater treatment plant sludge (primary raw sludge), semi-continuous flow anaerobic co-digestion with FOG could effectively enhance biogas and methane production. Thermophilic (55 degrees C) co-digestions exhibited higher biogas production and degradation of organics than mesophilic co-digestions. The best biogas production rate of 17.4 +/- 0.86 L/d and methane content 67.9 +/- 1.46% was obtained with a thermophilic co-digestion at HRT = 24 days and OLR = 2.43 +/- 0.15 g TVS/Ld. These were 32.8% and 7.10% higher than the respective values from the mesophilic co-digestion under similar operating conditions.

  15. CFD simulation of anaerobic digester with variable sewage sludge rheology.

    Science.gov (United States)

    Craig, K J; Nieuwoudt, M N; Niemand, L J

    2013-09-01

    A computational fluid dynamics (CFD) model that evaluates mechanical mixing in a full-scale anaerobic digester was developed to investigate the influence of sewage sludge rheology on the steady-state digester performance. Mechanical mixing is provided through an impeller located in a draft tube. Use is made of the Multiple Reference Frame model to incorporate the rotating impeller. The non-Newtonian sludge is modeled using the Hershel-Bulkley law because of the yield stress present in the fluid. Water is also used as modeling fluid to illustrate the significant non-Newtonian effects of sewage sludge on mixing patterns. The variation of the sewage sludge rheology as a result of the digestion process is considered to determine its influence on both the required impeller torque and digester mixing patterns. It was found that when modeling the fluid with the Hershel-Bulkley law, the high slope of the sewage stress-strain curve at high shear rates causes significant viscous torque on the impeller surface. Although the overall fluid shear stress property is reduced during digestion, this slope is increased with sludge age, causing an increase in impeller torque for digested sludge due to the high strain rates caused by the pumping impeller. Consideration should be given to using the Bingham law to deal with high strain rates. The overall mixing flow patterns of the digested sludge do however improve slightly. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

    Directory of Open Access Journals (Sweden)

    RICARDO CAMACHO-MUÑOZ

    2014-12-01

    Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

  17. [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.

  18. 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.

  19. 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.

  20. Carbohydrate-enriched cyanobacterial biomass as feedstock for bio-methane production through anaerobic digestion

    DEFF Research Database (Denmark)

    Markou, Giorgos; Angelidaki, Irini; Georgakakis, Dimitris

    2013-01-01

    The anaerobic digestion performance using carbohydrate-enriched biomass of Arthrospira platensis was studied. The carbohydrate enrichment was achieved after the cultivation of A. platensis under phosphorus limitation conditions. Three biomass compositions (60%, 40% and 20% carbohydrates content) ...

  1. On the effect of aqueous ammonia soaking pretreatment on batch and continuous anaerobic digestion of digested swine manure fibers

    DEFF Research Database (Denmark)

    Mirtsou Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

    2012-01-01

    The continuously increasing demand for renewable energy sources renders anaerobic digestion to one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most of the biogas plants. Thus......, their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. Aqueous Ammonia Soaking (AAS) has been successfully applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester...... to enhance their methane productivity in batch experiments. In the present study, continuous experiments at a mesophilic (38°C) CSTR-type anaerobic digester fed with swine manure first and a mixture of manure with AAS-treated digested fibers in the sequel, were performed. The methane yield of AAS...

  2. 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.

  3. 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.

  4. Performance and microbial community dynamics in a two-phase anaerobic co-digestion system using cassava dregs and pig manure.

    Science.gov (United States)

    Ren, Jiwei; Yuan, Xufeng; Li, Jie; Ma, Xuguang; Zhao, Ye; Zhu, Wanbing; Wang, Xiaofen; Cui, Zongjun

    2014-03-01

    The two-phase anaerobic co-digestion of cassava dregs (CD) with pig manure (PM) was evaluated using four sequencing batch reactors (SBRs) and a continuously stirred tank reactor (CSTR). The effect of seven different PM to CD volatile solid ratios (10:0, 8:2, 6:4, 5:5, 4:6, 2:8 and 0:10) on the acidification phase was investigated. Results indicated the concentrations of soluble chemical oxygen demand, NH4-N and volatile fatty acids increased substantially at seven ratios. Co-acidification of PM and CD performed well. Methanogenic fermentation of the acidification products at seven ratios was steady in CSTR. The highest methane yield and VS removal of 0.352m(3)/kg VSadded and 68.5% were achieved at PM:CD (4:6). The microbial population in CSTR was analyzed using molecular methods. Findings revealed that bacteria such as Firmicutes and Bacteroidetes, archaea such as Methanobacteriales and Methanomicrobiales were advantageous populations. Co-digestion of PM and CD supported higher quantity and diversity of methanogens.

  5. 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.

  6. Anaerobic digestion of lignocellulosic biomass: challenges and opportunities.

    Science.gov (United States)

    Sawatdeenarunat, Chayanon; Surendra, K C; Takara, Devin; Oechsner, Hans; Khanal, Samir Kumar

    2015-02-01

    Anaerobic digestion (AD) of lignocellulosic biomass provides an excellent opportunity to convert abundant bioresources into renewable energy. Rumen microorganisms, in contrast to conventional microorganisms, are an effective inoculum for digesting lignocellulosic biomass due to their intrinsic ability to degrade substrate rich in cellulosic fiber. However, there are still several challenges that must be overcome for the efficient digestion of lignocellulosic biomass. Anaerobic biorefinery is an emerging concept that not only generates bioenergy, but also high-value biochemical/products from the same feedstock. This review paper highlights the current status of lignocellulosic biomass digestion and discusses its challenges. The paper also discusses the future research needs of lignocellulosic biomass digestion.

  7. Applications of the anaerobic digestion process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ellegaard, L.; Ahring, Birgitte Kiær

    2003-01-01

    and incineration of organic waste has become less desirable, and legislation, both in Europe and elsewhere, tends to favor biological treatment as a way of recycling minerals and nutrients of organic wastes from society back to the food production and supply chain. Removing the relatively wet organic waste from...... and resource/energy recovery have been developed. Treatment of biowastes by anaerobic digestion processes is in many cases the optimal way to convert organic waste into useful products such as energy (in the form of biogas) and a fertilizer product. Other waste management options, such as land filling......At the start of the new millennium waste management has become a political priority in many countries. One of the main problems today is to cope with an increasing amount of primary waste in an environmentally acceptable way. Biowastes, i.e., municipal, agricultural or industrial organic waste...

  8. Comparison of digestate from solid anaerobic digesters and dewatered effluent from liquid anaerobic digesters as inocula for solid state anaerobic digestion of yard trimmings.

    Science.gov (United States)

    Xu, Fuqing; Wang, Feng; Lin, Long; Li, Yebo

    2016-01-01

    To select a proper inoculum for the solid state anaerobic digestion (SS-AD) of yard trimmings, digestate from solid anaerobic digesters and dewatered effluent from liquid anaerobic digesters were compared at substrate-to-inoculum (S/I) ratios from 0.2 to 2 (dry basis), and total solids (TS) contents from 20% to 35%. The highest methane yield of around 244L/kg VSfeed was obtained at an S/I ratio of 0.2 and TS content of 20% for both types of inoculum. The highest volumetric methane productivity was obtained with dewatered effluent at an S/I ratio of 0.6 and TS content of 24%. The two types of inoculum were found comparable regarding methane yields and volumetric methane productivities at each S/I ratio, while using dewatered effluent as inoculum reduced the startup time. An S/I ratio of 1 was determined to be a critical level and should be set as the upper limit for mesophilic SS-AD of yard trimmings.

  9. Inactivation of dairy manure-borne pathogens by anaerobic digestion

    Science.gov (United States)

    Background: Anaerobic digestion of animal manure has the potential to inactivate enteric pathogens, thereby reducing exposures to livestock and humans when the products of digestion are disposed by land-spreading or irrigation or returned to livestock uses such as bedding. Data on digester effectiv...

  10. Mathematical modelling of anaerobic digestion processes: applications and future needs

    DEFF Research Database (Denmark)

    Batstone, Damien J.; Puyol, Daniel; Flores Alsina, Xavier

    2015-01-01

    of the role of the central carbon catabolic metabolism in anaerobic digestion, with an increased importance of phosphorous, sulfur, and metals as electron source and sink, and consideration of hydrogen and methane as potential electron sources. The paradigm of anaerobic digestion is challenged by anoxygenic...... phototrophism, where energy is relatively cheap, but electron transfer is expensive. These new processes are commonly not compatible with the existing structure of anaerobic digestion models. These core issues extend to application of anaerobic digestion in domestic plant-wide modelling, with the need......Anaerobic process modelling is a mature and well-established field, largely guided by a mechanistic model structure that is defined by our understanding of underlying processes. This led to publication of the IWA ADM1, and strong supporting, analytical, and extension research in the 15 years since...

  11. Recovery of energy from Taro (Colocasia esculenta) with solid-feed anaerobic digesters (SOFADs).

    Science.gov (United States)

    Bindu, T; Ramasamy, E V

    2008-01-01

    We present studies on solid-feed anaerobic digesters (SOFADs) in which chopped Colocasia esculenta was fed without any other pretreatment, in an attempt to develop an efficient means of utilizing the semi-aquatic weed that is otherwise an environmental nuisance. Two types of SOFADs were studied. The first type had a single vessel with two compartments. The lower portion of the digester, 25% of the total volume, was separated from the upper by a perforated PVC disk. The weed was charged from the top and inoculated with anaerobically digested cow dung-water slurry. The fermentation of the weed in the digester led to the formation of volatile fatty acids (VFAs) plus some biogas. The bioleachate, rich in the VFAs, passed through the perforated PVC disk and was collected in the lower compartment of the digester. The other type of digesters, referred to as anaerobic multi-phase high-solids digesters (AMHDs), had the same type of compartmentalized digester unit as the first type and an additional methaniser unit. Up-flow anaerobic filters (UAFs) were used as methaniser units, which converted the bioleachate into combustible biogas consisting of approximately 60% methane. All SOFADs developed a consistent performance in terms of biogas yield within 20 weeks from the start. Among the two types of digesters studied, the AMHDs were found to perform better with a twofold increase in biogas yield compared to the first type of digesters.

  12. Inhibition of the anaerobic digestion process by linear alkylbenzene sulfonates

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Ahring, Birgitte Kiær

    2002-01-01

    it is important to investigate the effect of these xenobiotic compounds on an anaerobic environment. The inhibitory effect of Linear Alkylbenzene Sulfonates (LAS) on the acetogenic and methanogenic step of the anaerobic digestion process was studied. LAS inhibit both acetogenesis from propionate...... of the anaerobic digestion process should be seriously taken into consideration when wastewater from a surfactant producing industry is to be treated biologically or enter a municipal wastewater treatment plant that employs anaerobic technology. The upper allowable biomass specific LAS concentration should be 14...

  13. 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.

  14. Behaviour of emerging contaminants in sewage sludge after anaerobic digestion.

    Science.gov (United States)

    Boix, C; Ibáñez, M; Fabregat-Safont, D; Morales, E; Pastor, L; Sancho, J V; Sánchez-Ramírez, J E; Hernández, F

    2016-11-01

    Nowadays, there is an increasing concern over the presence of contaminants in the aquatic environment, where they can be introduced from wastewater after their incomplete removal in the treatment plants. In this work, degradation of selected emerging pollutants in the aqueous and solid phases of sewage sludge has been investigated after anaerobic digestion using two different digesters: mesophilic and thermophilic. Initially, sludge samples were screened by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) for identification of emerging contaminants in the samples. In a second step, a target quantitative method based on LC coupled to tandem MS was applied for selected pollutants identified in the previous screening. The behaviour of the compounds under anaerobic conditions was studied estimating the degradation efficiency and distribution of compounds between both sludge phases. Irbesartan and benzoylecgonine seemed to be notably degraded in both phases of the sludge. Venlafaxine showed a significant concentration decrease in the aqueous phase in parallel to an increase in the solid phase. The majority of the compounds showed an increase of their concentrations in both phases after the digestion. Concentrations in the solid phase were commonly higher than in the aqueous for most contaminants, indicating that they were preferentially adsorbed onto the solid particles.

  15. Anaerobic Digestion of Buffalo Dung: Simulation of Process Kinetics

    Directory of Open Access Journals (Sweden)

    Abdul Razaque Sahito

    2015-01-01

    Full Text Available Assessment of kinetic of AD (Anaerobic Digestion is a beneficial practice to forecast the performance of the process. It is helpful in the design of AD vessels, substrate feeding and digestate exit systems. The aim of this work was to assess the kinetics of anaerobically digested buffalo dung at different quantities of water added. It comprises the assessment of the specific methane production on the basis of VS (Volatile Solids added in each reactor by using three first order models, i.e. the modified Gompertz model, the Cone model and the Exponential Curve Factor model. The analysis was tested by using the three statistical parameters, i.e. the coefficient of multiple determinations, the standard deviation of residuals and the Akaike?s Information Criteria. The result reveals that the Exponential Curve Factor model was the best model that described the experimental data well. Moreover, there was not a direct or indirect relation between the kinetic coefficients of the AD process with the varying total or volatile solid content

  16. Tar water digestion in an upflow anaerobic sludge blanket reactor

    Energy Technology Data Exchange (ETDEWEB)

    Skibsted Mogensen, A.; Angelidaki, I.; Schmidt, J.E.; Ahring, B.K. [Technical Univ., Dept. of Environmental Science and Engineering, Lyngby (Denmark)

    1998-08-01

    The water from the gasification and wet oxidised tar water has been digested anaerobically in UASB reactors and were digested in respectively 10 and 50% in batches. Though the tar water show inhibition at very low concentrations to aerobic microorganisms, the granular sludge used in UASB reactors degrades tar water in concentrations that reveal total inhibition of e.g. bacteria conducting the nitrification process. The value of waste waters are determined, showing that the tar water produces more biogas in the anaerobic digestion. A wide range of xenobiotics, especially phenolic compounds can be transformed in the anaerobic digestion process. Seven phenolic are followed in batch experiments and UASB reactor experiments, and their particular fate in the anaerobic systems embody large differences in the transformation pattern. (au) 24 refs.

  17. Thermophilic anaerobic digestion versus mesophilic anaerobic digestion of sludges from WTP; Digestion anaerobic termofilica versus digestion anaerobia mesofilica de lodos del EDAR

    Energy Technology Data Exchange (ETDEWEB)

    Rubia de la Romero, M. A.; Perez Garcia, M.; Romero Garcia, L. I.; Sales Marquez, D.

    2001-07-01

    A literature search revealed that successful thermophilic digestion operation was achieved at several Sewage Treatment Plant: Hyperon Treatment Plant of the city of Los Angeles, operations at 49 degree centigree resulted in significant improvements in sludge handling characteristics; West-Southwest Sewage Treatment Works, Chicago, Illinois a stable thermophilic digester was established at a 8 day detention time; Lions Gate Wastewater Treatment Plant of Vancouver pathogen destruction was the primary goal of this evaluation. Several other investigators have also conducted laboratory as well as pilot scale studied and reported several potential advantages of operating anaerobic digesters in the thermophilic range, rather than the conventional mesophilic range. Increased destruction of pathogenic organisms, increased rate of volatile solids destruction and improved destruction of organics are some advantages reported by all authors. (Author) 16 refs.

  18. 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.

  19. Economic analysis of anaerobic digestion - A case of Green power biogas plant in The Netherlands

    NARCIS (Netherlands)

    Gebrezgabher, S.A.; Meuwissen, M.P.M.; Prins, B.A.M.; Oude Lansink, A.G.J.M.

    2010-01-01

    One of the key concerns of biogas plants is the disposal of comparatively large amounts of digestates in an economically and environmentally sustainable manner. This paper analyses the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal r

  20. Economic analysis of anaerobic digestion - A case of Green power biogas plant in The Netherlands

    NARCIS (Netherlands)

    Gebrezgabher, S.A.; Meuwissen, M.P.M.; Prins, B.A.M.; Oude Lansink, A.G.J.M.

    2010-01-01

    One of the key concerns of biogas plants is the disposal of comparatively large amounts of digestates in an economically and environmentally sustainable manner. This paper analyses the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal

  1. Microbiology of anaerobic digestion; Microbiologia da digestao anaerobica

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, Rosana Filomena Vazoller [CETESB, Sao Paulo, SP (Brazil)

    1988-12-31

    Considerations was made about the microorganisms involved in the anaerobic digestion of wastes. Are also presented, the main results on this subject obtained, until now, in the studies carried on the group of anaerobic microbiology researchers from the Sanitary Company of Sao Paulo State, Brazil. (author) 23 refs., 8 figs., 3 tabs.

  2. Inhibition of the anaerobic digestion process by linear alkylbenzene sulfonates

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Ahring, Birgitte Kiær

    2002-01-01

    of the anaerobic digestion process should be seriously taken into consideration when wastewater from a surfactant producing industry is to be treated biologically or enter a municipal wastewater treatment plant that employs anaerobic technology. The upper allowable biomass specific LAS concentration should be 14......Linear Alkylbenzene Sulfonates (LAS) are the most widely used synthetic anionic surfactants. They are anthropogenic, toxic compounds and are found in the primary sludge generated in municipal wastewater treatment plants. Primary sludge is usually stabilized anaerobically and therefore...

  3. Dry co-digestion of sewage sludge and rice straw under mesophilic and thermophilic anaerobic conditions.

    Science.gov (United States)

    Chu, Xiangqian; Wu, Guangxue; Wang, Jiaquan; Hu, Zhen-Hu

    2015-12-01

    Dry anaerobic digestion of sewage sludge can recover biogas as energy; however, its low C/N ratio limits it as a single substrate in the anaerobic digestion. Rice straw is an abundant agricultural residue in China, which is rich in carbon and can be used as carbon source. In the present study, the performance of dry co-digestion of sewage sludge and rice straw was investigated under mesophilic (35 °C) and thermophilic (55 °C) conditions. The operational factors impacting dry co-digestion of sewage sludge and rice straw such as C/N ratio, moisture content, and initial pH were explored under mesophilic conditions. The results show that low C/N ratios resulted in a higher biogas production rate, but a lower specific biogas yield; low moisture content of 65 % resulted in the instability of the digestion system and a low specific biogas yield. Initial pH ranging 7.0-9.0 did not affect the performance of the anaerobic digestion. The C/N ratio of 26-29:1, moisture content of 70-80 %, and pH 7.0-9.0 resulted in good performance in the dry mesophilic co-digestion of sewage sludge and rice straw. As compared with mesophilic digestion, thermophilic co-digestion of sewage sludge and rice straw significantly enhanced the degradation efficiency of the substrates and the specific biogas yield (p co-digestion of sewage sludge under mesophilic and thermophilic conditions.

  4. Thermal pretreatment of algae for anaerobic digestion.

    Science.gov (United States)

    Marsolek, Michael D; Kendall, Elizabeth; Thompson, Phillip L; Shuman, Teodora Rutar

    2014-01-01

    The objective of this work was to determine the benefit of thermal pretreatment on biogas yield from microalgae-fed anaerobic digester mesocosms. Replicate Nanochloropsis oculata cultures were heated for 4h at 30, 60, and 90°C, as well as at a constant temperature of 90°C for 1, 3.5, and 12h. Net biogas production increased from 0.28L biogas/g volatile solids added (VSa) for the control to 0.39 L biogas/g VSa (p<0.01) when heated at 90°C, but there was no improvement at 30 or 60°C. Increased biogas production correlated with increased soluble chemical oxygen demand (COD). Net biogas production increased as a function of heating time, from 0.32 L biogas/g VSa for the control, to 0.41, 0.43, and 0.44 L biogas/g VSa (p<0.05 for all combinations vs. control) when preheated at 90°C for 1, 3.5, and 12h, respectively. However, despite enhanced biogas production the energy balance is negative for thermal pretreatment.

  5. Anaerobic digestion of food waste through the operation of a mesophilic two-phase pilot scale digester--assessment of variable loadings on system performance.

    Science.gov (United States)

    Grimberg, S J; Hilderbrandt, D; Kinnunen, M; Rogers, S

    2015-02-01

    Single and two-phase operations were compared at mesophilic operating conditions using a digester system consisting of three 5-m(3) reactors treating food waste generated daily within the university campus kitchens. When normalizing the methane production to the daily feedstock characteristics, significantly greater methane was produced during two-phase mesophilic digestion compared to the single-stage operation (methane yield of 380 vs 446-L CH4 kg VS(-1); 359 vs 481-L CH4 kg COD(-1) removed for single vs two stage operation). The fermentation reactor could be maintained reliably even under very low loading rates (0.79±0.16 kg COD m(-3) d(-1)) maintaining a steady state pH of 5.2. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Impact of the substrate loading regime and phosphoric acid supplementation on performance of biogas reactors and microbial community dynamics during anaerobic digestion of chicken wastes.

    Science.gov (United States)

    Belostotskiy, Dmitry E; Ziganshina, Elvira E; Siniagina, Maria; Boulygina, Eugenia A; Miluykov, Vasili A; Ziganshin, Ayrat M

    2015-10-01

    This study evaluates the effects of increasing organic loading rate (OLR) and decreasing hydraulic retention time (HRT) as well as phosphoric acid addition on mesophilic reactors' performance and biogas production from chicken wastes. Furthermore, microbial community composition in reactors was characterized by a 16S rRNA gene-based pyrosequencing analysis. Each step of increasing OLR impacted on the activity of microorganisms what caused a temporary decrease in biogas production. The addition of phosphoric acid resulted in the increased biogas production with values between 361 and 447 mL g(VS)(-1) from day 61 to day 74 compared to control reactor (309-350 mL g(VS)(-1)). With reactors' operation, Bacteroidetes phylotypes were noticeably replaced with Firmicutes representatives, and significant increase of Clostridium sp. was identified. Within Euryarchaeota, Methanosarcina sp. dominated in all analyzed samples, in which high ammonium levels were detected (3.4-4.9 NH4(+)-N g L(-1)). These results can help in better understanding the anaerobic digestion process of simultaneously ammonium/phosphate-rich substrates.

  7. Removal of polycyclic aromatic hydrocarbons (PAH) during anaerobic digestion with recirculation of ozonated digested sludge

    Energy Technology Data Exchange (ETDEWEB)

    Bernal-Martinez, Arodi; Patureau, Dominique; Delgenes, Jean-Philippe [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France); Carrere, Helene [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France)], E-mail: carrere@supagro.inra.fr

    2009-03-15

    PAH are particularly monitored because of their carcinogenic properties and their ubiquity in the environment. Their presence in municipal sewage sludge is a major problem due to the environmental risks associated with the sludge spreading on agricultural soils. The objective of this work was to asses the removal of PAH naturally present in sludge by continuous anaerobic digestion with recirculation of ozonated sludge. Recirculation of ozonated digested sludge allowed to enhance PAH removals, the highest efficiency was obtained with the highest ozone dose (0.11 g O{sub 3}/g{sub TS}). In order to study the effect of recirculation, a reactor was operated without recirculation but was fed with a mixture of raw and ozonated digested sludge. This process led to the best performances in terms of PAH and solid removals. This pointed out some accumulation of nonbiodegradable or recalcitrant compounds during recirculation assay. Smallest and most soluble compounds presented the highest biodegradation efficiencies.

  8. Effects of ion strength and ion pairing on (plant-wide) modelling of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Mbamba, Christian Kazadi; Solon, Kimberly;

    2014-01-01

    The objective of this study is to show the influence of ionic strength (as activity corrections) andion pairing on (plant-wide) modelling of anaerobic digestion processes in wastewater treatment plants(WWTPs). Using the Benchmark Simulation Model No. 2 (BSM2) as a case study, this paper presents...... the effects that an improved physico-chemical description will have on the predicted effluent quality (EQI) and operational cost (OCI) indices. The acid-base equilibria implemented in the Anaerobic Digestion Model No.1 (ADM1) are modified to account for non-ideal aqueous-phase chemistry. The model corrects...... processes. Results at high ionic strength demonstrate that corrections to account for non-ideal conditions lead to significant differences in predicted process performance. In addition, the paper describes: 1) how the anaerobic digester performance is affected; 2) the effect on pH and the anaerobic...

  9. Anaerobic digestion of selected Italian agricultural and industrial residues (grape seeds and leather dust): combined methane production and digestate characterization.

    Science.gov (United States)

    Caramiello, C; Lancellotti, I; Righi, F; Tatàno, F; Taurino, R; Barbieri, L

    2013-01-01

    A combined experimental evaluation of methane production (obtained by anaerobic digestion) and detailed digestate characterization (with physical-chemical, thermo-gravimetric and mineralogical approaches) was conducted on two organic substrates, which are specific to Italy (at regional and national levels). One of the substrates was grape seeds, which have an agricultural origin, whereas the other substrate was vegetable-tanned leather dust, which has an industrial origin. Under the assumed experimental conditions of the performed lab-scale test series, the grape seed substrate exhibited a resulting net methane production of 175.0 NmL g volatile solids (VS)(-1); hence, it can be considered as a potential energy source via anaerobic digestion. Conversely, the net methane production obtained from the anaerobic digestion of the vegetable-tanned leather dust substrate was limited to 16.1 NmL gVS(-1). A detailed characterization of the obtained digestates showed that there were both nitrogen-containing compounds and complex organic compounds present in the digestate that was obtained from the mixture of leather dust and inoculum. As a general perspective of this experimental study, the application of diversified characterization analyzes could facilitate (1) a better understanding of the main properties of the obtained digestates to evaluate their potential valorization, and (2) a combination of the digestate characteristics with the corresponding methane productions to comprehensively evaluate the bioconversion process.

  10. Trace metal speciation and bioavailability in anaerobic digestion: A review.

    Science.gov (United States)

    Thanh, Pham Minh; Ketheesan, Balachandran; Yan, Zhou; Stuckey, David

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR).

  11. Anaerobic digestion technology in livestock manure treatment for biogas production: a review

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, Ismail M. [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, Selangor (Malaysia); Mohd Ghazi, Tinia I.; Omar, Rozita

    2012-06-15

    This article reviews the potential of anaerobic digestion (AD) for biogas production from livestock manure wastes and compares the operating and performance data for various anaerobic process configurations. It examines different kinds of manure waste treatment techniques and the influence of several parameters on biogas and methane yield. The comparison indicates that a variety of different operational conditions, various reactor configurations such as batch reactors, continuously stirred tank reactor (CSTR), plug flow reactor (PFR), up-flow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), temperature phased anaerobic digestion (TPAD), and continuous one- and two-stage systems, present a suitable technology for the AD of livestock manure waste. Main performance indicators are biogas and methane yield, degradation of volatile solids (VS), higher loading, and process stability with a short retention time. (copyright 2012 WILEY-VCH Verlag GmbH 8 Co. KGaA, Weinheim)

  12. The environmental sustainability of anaerobic digestion as a biomass valorization technology.

    Science.gov (United States)

    De Meester, Steven; Demeyer, Jens; Velghe, Filip; Peene, Andy; Van Langenhove, Herman; Dewulf, Jo

    2012-10-01

    This paper studies the environmental sustainability of anaerobic digestion from three perspectives. First, reference electricity is compared to electricity production from domestic organic waste and energy crop digestion. Second, different digester feed possibilities in an agricultural context are studied. Third, the influence of applying digestate as fertilizer is investigated. Results highlight that biomass is converted at a rational exergy (energy) efficiency ranging from 15.3% (22.6) to 33.3% (36.0). From a life cycle perspective, a saving of over 90% resources is achieved in most categories when comparing biobased electricity to conventional electricity. However, operation without heat valorization results in 32% loss of this performance while using organic waste (domestic and agricultural residues) as feedstock avoids land resources. The use of digestate as a fertilizer is beneficial from a resource perspective, but causes increased nitrogen and methane emissions, which can be reduced by 50%, making anaerobic digestion an environmentally competitive bioenergy technology.

  13. Optimisation and inhibition of anaerobic digestion of livestock manure

    Energy Technology Data Exchange (ETDEWEB)

    Sutaryo, S.

    2012-11-15

    The optimisation process during this PhD study focused on mixed enzyme (ME) addition, thermal pre-treatment and co-digestion of raw manure with solid fractions of acidified manure, while for inhibition processes, ammonia and sulphide inhibition were studied. ME addition increased methane yield of both dairy cow manure (DCM) and solid fractions of DCM (by 4.44% and 4.15% respectively, compared to the control) when ME was added to manure and incubated prior to anaerobic digestion (AD). However, no positive effect was found when ME was added to manure and fed immediately to either mesophilic (35 deg. C) or thermophilic (50 deg. C) digesters. Low-temperature pre-treatment (65 deg. C to 80 deg. C for 20 h) followed by batch assays increased the methane yield of pig manure in the range from 9.5% to 26.4% at 11 d incubation. These treatments also increased the methane yield of solid-fractions pig manure in the range from 6.1% to 25.3% at 11 d of the digestion test. However, at 90 d the increase in methane yield of pig manure was only significant at the 65 deg. C treatment, thus low-temperature thermal pre-treatment increased the rate of gas production, but did not increase the ultimate yield (B{sub o}). High-temperature pre-treatment (100 deg. C to 225 deg. C for 15 min.) increased the methane yield of DCM by 13% and 21% for treatments at 175 deg. C and 200 deg. C, respectively, at 27 d of batch assays. For pig manure, methane yield was increased by 29% following 200 deg. C treatment and 27 d of a batch digestion test. No positive effect was found of high-temperature pre-treatment on the methane yield of chicken manure. At the end of the experiment (90 d), high-temperature thermal pre-treatment was significantly increasing the B{sub 0} of pig manure and DCM. Acidification of animal manure using sulphuric acid is a well-known technology to reduce ammonia emission of animal manure. AD of acidified manure showed sulphide inhibition and consequently methane production was 45

  14. Mesophilic anaerobic digestion of several types of spent livestock bedding in a batch leach-bed reactor: substrate characterization and process performance.

    Science.gov (United States)

    Riggio, S; Torrijos, M; Debord, R; Esposito, G; van Hullebusch, E D; Steyer, J P; Escudié, R

    2017-01-01

    Spent animal bedding is a valuable resource for green energy production in rural areas. The properties of six types of spent bedding collected from deep-litter stables, housing either sheeps, goats, horses or cows, were compared and their anaerobic digestion in a batch Leach-Bed Reactor (LBR) was assessed. Spent horse bedding, when compared to all the other types, appeared to differ the most due to a greater amount of straw added to the litter and a more frequent litter change. Total solids content appeared to vary significantly from one bedding type to another, with consequent impact on the methane produced from the raw substrate. However, all the types of spent bedding had similar VS/TS (82.3-88.9)%, a C/N well-suited to anaerobic digestion (20-28, except that of the horse, 42) and their BMPs were in a narrow range (192-239NmLCH4/gVS). The anaerobic digestion in each LBR was stable and the pH always remained higher than 6.6 regardless of the type of bedding. In contrast to all the other substrates, spent goat bedding showed a stronger acidification resulting in a methane production lag phase. Finally, spent bedding of different origins reached, on average, (89±11)% of their BMP after 60days of operation. This means that this waste is well-suited for treatment in LBRs and that this is a promising process to recover energy from dry agricultural waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Assessing the agricultural reuse of the digestate from microalgae anaerobic digestion and co-digestion with sewage sludge.

    Science.gov (United States)

    Solé-Bundó, Maria; Cucina, Mirko; Folch, Montserrat; Tàpias, Josefina; Gigliotti, Giovanni; Garfí, Marianna; Ferrer, Ivet

    2017-05-15

    Microalgae anaerobic digestion produces biogas along with a digestate that may be reused in agriculture. However, the properties of this digestate for agricultural reuse have yet to be determined. The aim of this study was to characterise digestates from different microalgae anaerobic digestion processes (i.e. digestion of untreated microalgae, thermally pretreated microalgae and thermally pretreated microalgae in co-digestion with primary sludge). The main parameters evaluated were organic matter, macronutrients and heavy metals content, hygenisation, potential phytotoxicity and organic matter stabilisation. According to the results, all microalgae digestates presented suitable organic matter and macronutrients, especially organic and ammonium nitrogen, for agricultural soils amendment. However, the thermally pretreated microalgae digestate was the least stabilised digestate in comparison with untreated microalgae and co-digestion digestates. In vivo bioassays demonstrated that the digestates did not show residual phytotoxicity when properly diluted, being the co-digestion digestate the one which presented less phytotoxicity. Heavy metals contents resulted far below the threshold established by the European legislation on sludge spreading. Moreover, low presence of E. coli was observed in all digestates. Therefore, agricultural reuse of thermally pretreated microalgae and primary sludge co-digestate through irrigation emerges a suitable strategy to recycle nutrients from wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Anaerobic Co-Digestion of the Microalgae Scenedesmus Sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Suarez, J. L.; Carreras, N.

    2011-06-07

    Microalgae biomass has been widely studied for biogas production over the last years and results show that anaerobic digestion is often limited by the low C/N ratio of this type of biomass. Therefore, codigestion with substrates of high C/N ratio is necessary. The objectives of this study are to set up an experimental method that ease reproducibility and control of anaerobic digestion processes in laboratory conditions and to determine the biodegradability and biogas production potential of the co-digestion process of microalgae Scenedesmus sp. and energy crop Opuntia ficus indica (L.) Miller. Results obtained showed that higher C/N ratios are preferred in order to maximize methane production. Highest methane yield obtained was 0.252m3CH4/Kg VS and degradability expressed as percentage COD reduced is around 30% for the ideal mixture found, made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. A laboratory setup using MicroOxymax respirometer, after its adaptation to work under anaerobic conditions, can be used for the monitoring of anaerobic digestion processes. Scenedesmus sp. as sole substrate for anaerobic digestion does not give good results due to low C/N ratio. However, when codigesting it with O. ficus-indica methane production is satisfactory. Best mixture was made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. (Author)

  17. Testing low cost anaerobic digestion (AD) systems

    Science.gov (United States)

    To evaluate the potential for low technology and low cost digesters for small dairies, BARC and researchers from the University of Maryland installed six modified Taiwanese-model field-scale (FS) digesters near the original dairy manure digester. The FS units receive the same post-separated liquid ...

  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. 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).

  20. Dry anaerobic digestion of lignocellulosic and protein residues

    Directory of Open Access Journals (Sweden)

    Maryam M Kabir

    2015-12-01

    Full Text Available Utilisation of wheat straw and wool textile waste in dry anaerobic digestion (AD process was investigated. Dry-AD of the individual substrates as well as co-digestion of those were evaluated using different total solid (TS contents ranging between 6 to 30%. Additionally, the effects of the addition of nutrients and cellulose- or protein-degrading enzymes on the performance of the AD process were also investigated. Dry-AD of the wheat straw resulted in methane yields of 0.081 – 0.200 Nm3CH4/kgVS with the lowest and highest values obtained at 30 and 21% TS, respectively. The addition of the cellulolytic enzymes could significantly increase the yield in the reactor containing 13% TS (0.231 Nm3CH4/kg VS. Likewise, degradation of wool textile waste was enhanced significantly at TS of 13% with the addition of the protein-degrading enzyme (0.131 Nm3CH4/kg VS. Furthermore, the co-digestion of these two substrates showed higher methane yields compared with the methane potentials calculated for the individual fractions at all the investigated TS contents due to synergetic effects and better nutritional balance.

  1. Effect of digestion time on anaerobic digestion with high ammonia concentration

    Science.gov (United States)

    Oktavitri, Nur Indradewi; Purnobasuki, Hery; Kuncoro, Eko Prasetyo; Purnamasari, Indah; Semma Hadinnata, P.

    2016-03-01

    Anaerobic digestion was developed to treat high concentration organic compound efficiently in certain Digestion Time (DT). High ammonia concentration could influenced removal organic compound in digestion. This bench scale study investigated the effect of digestion time on anaerobic batch reactor with high ammonia concentration. Total Ammonia Nitrogen (TAN) concentration was adjusted 4000 and 5000 mg/1, Digestion time was ranged from 0-26 d, operation temperature was ranged from 28-29°C, inoculum was collected from slaughter house sludge. The degradation of Chemical Oxygen Demand (COD) correlated with digestion time. The concentration of TAN from synthetic wastewater contain 5000 mg/1 of TAN more fluctuated than those use 4000 mg/1 of TAN. However, the biogas production from wastewater contained 4000 mg/1 of TAN gradually increased until 24 d of DT. The reactor contain 5000 mg/1 of TAN only growth until 12 d and steady state at over 12 d of digestion time.

  2. Model selection, identification and validation in anaerobic digestion: a review.

    Science.gov (United States)

    Donoso-Bravo, Andres; Mailier, Johan; Martin, Cristina; Rodríguez, Jorge; Aceves-Lara, César Arturo; Vande Wouwer, Alain

    2011-11-01

    Anaerobic digestion enables waste (water) treatment and energy production in the form of biogas. The successful implementation of this process has lead to an increasing interest worldwide. However, anaerobic digestion is a complex biological process, where hundreds of microbial populations are involved, and whose start-up and operation are delicate issues. In order to better understand the process dynamics and to optimize the operating conditions, the availability of dynamic models is of paramount importance. Such models have to be inferred from prior knowledge and experimental data collected from real plants. Modeling and parameter identification are vast subjects, offering a realm of approaches and methods, which can be difficult to fully understand by scientists and engineers dedicated to the plant operation and improvements. This review article discusses existing modeling frameworks and methodologies for parameter estimation and model validation in the field of anaerobic digestion processes. The point of view is pragmatic, intentionally focusing on simple but efficient methods.

  3. 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.

  4. Modeling flow inside an anaerobic digester by CFD techniques

    OpenAIRE

    2011-01-01

    Anaerobic processes are used to treat high strength organic wastewater as well as for the treatment of primary and secondary sludge from conventional wastewater treatment plants. In these processes, heterotrophic microorganisms convert biodegradable organic matter to methane and carbon dioxide in the absence of dissolved oxygen and nitrate. Some of the most important aspects of the design of anaerobic digesters are related to hydraulic considerations. In spite of its impor...

  5. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Rejean Samson; Anh LeDuy

    1982-08-01

    Spirulina maxima algal biomass could be used as the sole nutrient for the production of biogas by anaerobic digestion process. It is relatively simple to adapt the municipal sewage sludge to this new substrate. The adapted sludge is very stable. Under nonoptimal conditions, the methane yield and productivity obtained were 0.26 m/sup 3//(kg VS added day) and 0.26 m/sup 3//(kg VS added day), respectively, with the semicontinuous, daily fed, anaerobic digestion having loading rate of 0.97 kg VS/(m/sup 3/ day), retention time of 33 days and temperature of 30/sup 0/C.

  6. 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.

  7. 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.

  8. 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

  9. Anaerobic co-digestion of cyanide containing cassava pulp with pig manure.

    Science.gov (United States)

    Glanpracha, Naraporn; Annachhatre, Ajit P

    2016-08-01

    Anaerobic co-digestion of cyanide-containing cassava pulp with pig manure was evaluated using laboratory scale mesophilic digester. The digester was operated in a semi-continuous mode with the mixed feedstock having C/N ratio of 35:1. Digester startup was accomplished in 60days with loading of 0.5-1kgVS/m(3)d. Subsequently, the loading to digester was increased step-wise from 2 to 9kgVS/m(3)d. Digester performance was stable at loading between 2 and 6kgVS/m(3)d with an average volatile solid removal and methane yield of 82% and 0.38m(3)/kgVSadded, respectively. However, beyond loading of 7kgVS/m(3)d, solubilization of particulate matter did not take place efficiently. Cyanide present in cassava pulp was successfully degraded indicating that anaerobic sludge in the digester was well acclimatized to cyanide. The results show that cassava pulp can be successfully digested anaerobically with pig manure as co-substrate without any inhibitory effect of cyanide present in the cassava pulp.

  10. Low-heat, mild alkaline pretreatment of switchgrass for anaerobic digestion.

    Science.gov (United States)

    Jin, Guang; Bierma, Tom; Walker, Paul M

    2014-01-01

    This study examines the effectiveness of alkaline pretreatment under mild heat conditions (100°C or 212°F) on the anaerobic co-digestion of switchgrass. The effects of alkaline concentration, types of alkaline, heating time and rinsing were evaluated. In addition to batch studies, continuous-feed studies were performed in triplicate to identify potential digester operational problems caused by switchgrass co-digestion while accounting for uncertainty due to digester variability. Few studies have examined anaerobic digestion of switchgrass or the effects of mild heating to enhance alkaline pretreatment prior to biomass digestion. Results indicate that pretreatment can significantly enhance digestion of coarse-ground (≤ 0.78 cm particle size) switchgrass. Energy conversion efficiency as high as 63% was observed, and was comparable or superior to fine-grinding as a pretreatment method. The optimal NaOH concentration was found to be 5.5% (wt/wt alkaline/biomass) with a 91.7% moisture level. No evidence of operational problems such as solids build-up, poor mixing, or floating materials were observed. These results suggest the use of waste heat from a generator could reduce the concentration of alkaline required to adequately pretreat lignocellulosic feedstock prior to anaerobic digestion.

  11. Single stage anaerobic digester at Tarleton State University. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    The design and operation of the demonstration plant facilities at Tarleton State University to produce methane in a single stage anaerobic digester are described. A combination of manures from hogs and poultry are used as feedstock. Uses for the methane, cost of the digester, and value of the energy produced are discussed. During the 21 months of operation, 310 people have visited the project. (DMC)

  12. Rheology evolution of sludge through high-solid anaerobic digestion.

    Science.gov (United States)

    Dai, Xiaohu; Gai, Xin; Dong, Bin

    2014-12-01

    The main purpose of this study was to investigate the rheology evolution of sludge through high-solid anaerobic digestion (AD) and its dependency on sludge retention time (SRT) and temperature of AD reactor. The operation performance of high-solid AD reactors were also studied. The results showed that sludge became much more flowable after high-solid AD. It was found that the sludge from reactors with long SRT exhibited low levels of shear stress, viscosity, yield stress, consistency index, and high value of flow behaviour index. While the flowability of sludge from thermophilic AD reactors were better than that of sludge from mesophilic AD reactors though the solid content of the formers were higher than that of the latters, which could be attributed to the fact that the formers had more amount of free and interstitial moisture. It might be feasible to use sludge rheology as an AD process controlling parameter. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Anaerobic sludge digestion with a biocatalytic additive. [Lactobacillus acidophilus

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    Aimed at improving the process operating characteristics of anaerobic digestion for sludge stabilization and SNG production, this study evaluates the effects of a lactobacillus additive under normal, variable, and overload conditions. This whey fermentation product of an acid-tolerant strain of L. acidophilus fortified with CoCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. Data indicate that the biochemical additive increases methane yield, gas production rate, and volatile solids reduction; decreases volatile acids accumulation; enhances the digester buffer capacity; and improves the fertilizer value and dewatering characteristics of the digested residue. Digester capacities could be potentially doubled when the feed is so treated. Results of field tests with six full-scale digesters confirm observations made with bench-scale digesters.

  14. Anaerobic digestion and digestate use: accounting of greenhouse gases and global warming contribution

    DEFF Research Database (Denmark)

    Møller, Jacob; Boldrin, Alessio; Christensen, Thomas Højlund

    2009-01-01

    Anaerobic digestion (AD) of source-separated municipal solid waste (MSW) and use of the digestate is presented from a global warming (GW) point of view by providing ranges of greenhouse gas (GHG) emissions that are useful for calculation of global warming factors (GWFs), i.e. the contribution to GW...

  15. 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.

  16. Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion.

    Science.gov (United States)

    Marques, Isabel Paula; Gil, Luís; La Cara, Francesco

    2014-01-01

    In addition to energy benefits, anaerobic digestion offers other interesting advantages. The cork industry is of great environmental, economic and social significance in the western Mediterranean region, with Portugal being the world-leading producer and exporter. Cork boiling wastewater (CBW) is a toxic and recalcitrant organic effluent produced by this sector, which constitutes a serious environmental hazard. However, there is no documented research on anaerobic treatment/valorization performed with this effluent. The work presented here was developed with the aim to use the anaerobic digestion process to convert the CBW polluting organic load into an energy carrier gas and valuable molecules for industry. No lag phases were observed and a methane yield of 0.126 to 0.142 m(3) kg(-1) chemical oxygen demand (COD)added was registered in the mesophilic consortium experiments carried out in batch flasks at 37 ± 1°C. Anaerobic digestion can be advantageously connected to ultrafiltration or electrochemical processes, due to the following: 1) reduction of ellagic acid content and consequent decrease of CBW viscosity; and 2) increase in conductivity after the anaerobic process, avoiding the electrolyte application of the electrochemical process. The improvement of several CBW biochemical features shows that anaerobic digestion may provide additionally useful molecules. The rise in concentration of some of these compounds, belonging to the benzoic acid family (gallic, protocatechuic, vanillic and syringic acids), is responsible for the increase of antiradical activity of the phenolic fraction. Additionally, some enzymatic activity was also observed and while the laccase activity increased in the digested effluent by anaerobiosis, xylanase was formed in the process. The multidisciplinary approach adopted allowed the valorization of CBW in terms of energy and valuable biomolecules. By exploiting the anaerobic digestion process potential, a novel methodology to toxic

  17. 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.

  18. Digestate from anaerobic reactor as a potential fertilizer

    Directory of Open Access Journals (Sweden)

    Navodita Bhatnagar

    2015-04-01

    Full Text Available Biogas is one of the most promising sources of renewable energy in today’s world. Liquid and the solid digestates are the byproducts of anaerobic digestion of various kinds of wastes to produce biogas. Disposal of liquid digestate is one of the major issues faced by the existing biogas plant facilities worldwide. In this study, liquid digestate from anaerobic digestion of food waste is examined for its potential as an organic fertilizer for food crops. Coconut peat is used as a matrix to hold the digestate and also to grow plants in a soil-less culture. Three plants from the family- Solanaceae were chosen viz. tomato (Solanum lycopersicum, green chilli (Capsicum annum and eggplant or brinjal (Solanum melogena. The plants were grown in trays as control (coconut peat and water and slurry (coconut peat and digestate. Digestate sets showed an increase in growth parameters as compared to control by a factor of 60.8% in tomato, 48.6% in chilli and 97% in brinjal for plant height, 86% in tomato, 82.4% in chilli and 63.8% in brinjal for leaf length, and 66.3% in tomato, 87.3% in chilli for number of leaves. The final yield for chilli plants was 2.5 fruits/plant in 70 days while for brinjal it was 2 fruits/plant after 74 days of growth.

  19. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

    Science.gov (United States)

    Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  20. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    Energy Technology Data Exchange (ETDEWEB)

    Gannoun, H.; Bouallagui, H.; Okbi, A. [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia); Sayadi, S. [Laboratory of bioprocesses, Centre of Biotechnology of Sfax, Sfax (Tunisia); Hamdi, M., E-mail: moktar.hamdi@insat.rnu.tn [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia)

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  1. 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.

  2. 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.

  3. Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).

    Science.gov (United States)

    Blumensaat, F; Keller, J

    2005-01-01

    The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale.

  4. Wet and Dry Anaerobic Digestion of Biowaste and of Co-substrates

    OpenAIRE

    Li, Chaoran

    2015-01-01

    Treatment of municipal solid waste by anaerobic digestion can solve the environmental problems caused by this organic solid waste and also supply biogas as renewable energy for a sustainable development. In this study the improvement of wet anaerobic digestion by addition of co-substrates and the effect of moisture on dry anaerobic digestion were investigated.

  5. 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.

  6. Effects of ionic strength and ion pairing on (plant-wide) modelling of anaerobic digestion

    DEFF Research Database (Denmark)

    Solon, Kimberly; Flores Alsina, Xavier; Mbamba, Christian Kazadi

    2015-01-01

    ) and ion pairing on modelling of anaerobic digestion processes in such plant-wide models of wastewater treatment. Using the BSM2 as a case study with a number of model variants and cationic load scenarios, this paper presents the effects of an improved physico-chemical description on model predictions....... The paper describes: 1) how the anaerobic digester performance is affected by physico-chemical corrections; 2) the effect on pH and the anaerobic digestion products (CO2, CH4 and H2); and, 3) how these variations are propagated from the sludge treatment to the water line. Results at high ionic strength......Plant-wide models of wastewater treatment (such as the Benchmark Simulation Model No. 2 or BSM2) are gaining popularity for use in holistic virtual studies of treatment plant control and operations. The objective of this study is to show the influence of ionic strength (as activity corrections...

  7. Rate determination of supercritical water gasification of primary sewage sludge as a replacement for anaerobic digestion.

    Science.gov (United States)

    Wilkinson, Nikolas; Wickramathilaka, Malithi; Hendry, Doug; Miller, Andrew; Espanani, Reza; Jacoby, William

    2012-11-01

    Supercritical water gasification of primary sewage sludge sampled from a local facility was undertaken at different solids content. The performance of the process was compared with the anaerobic digestion system in use at the facility where the samples were taken. The mass and composition of the vapor products documented showed that the process generates more energy per gram of feed while rapidly destroying more volatile solids relative to the anaerobic digestion process. However, the energy input requirements are greater for supercritical water gasification. This study defines parameters for a model of the gasification reaction using the power law and Arrhenius equation. The activation energy was estimated to be 15 kJ/mol, and the reaction order was estimated to be 0.586. This model allows estimation of the size of a supercritical water reactor needed to replace the anaerobic digesters that are currently used at the wastewater treatment plant.

  8. Making lignin accessible for anaerobic digestion by wet-explosion pretreatment

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Biswas, Rajib; Ahamed, Aftab

    2015-01-01

    Lignin is a major part of the recalcitrant fraction of lignocellulose and in nature its degradation occurs through oxidative enzymes along with microbes mediated oxidative chemical actions. Oxygen assisted wet-explosion pretreatment promotes lignin solubility and leads to an increase biodegradation...... of lignin during anaerobic digestion processes. The pretreatment of feedlot manure was performed in a 10 L reactor at 170 C for 25 min using 4 bars oxygen and the material was fed to a continuous stirred tank reactor operated at 55 C for anaerobic digestion. Methane yield of untreated and pretreated...... material was 70 ± 27 and 320 ± 36 L/kg-VS/day, respectively, or 4.5 times higher yield as a result of the pretreatment. Aliphatic acids formed during the pretreatment were utilized by microbes. 44.4% lignin in pretreated material was actually converted in the anaerobic digestion process compared to 12...

  9. Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

    Science.gov (United States)

    Valle-Guadarrama, Salvador; Espinosa-Solares, Teodoro; López-Cruz, Irineo L; Domaschko, Max

    2011-05-01

    A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.

  10. Biogas from renewable resources through dry anaerobic digestion; Biogas aus NaWaRos durch Trockenfermentation

    Energy Technology Data Exchange (ETDEWEB)

    Heiermann, M. [ATB, Potsdam (Germany). Abt. Technikbewertung und Stoffkreislaeufe; Linke, B. [ATB, Potsdam (Germany). Abt. Bioverfahrenstechnik; Kessler, U. [Agrargenossenschaft Pirow e.G. (Germany). Biogasanlage; Loock, R. [Ingenieurbuero Loock Consultants, Hamburg (Germany)

    2007-07-01

    The functionality, performance and operational safety of anaerobic digestion using the dry-wet simultaneous technique of Loock Consultants were investigated at the biogas pilot plant in Pirow (State Brandenburg). In addition to determining process parameters and the input and output balance of the digester, chemical characterisation of the substrates and their biogas production potential were determined in the laboratory. The results reveal that a substrate mixture of 60% maize silage, 13% poultry manure and 27% digested material on a mass basis deliver a methane yield of 90 m{sup 3}t{sup -1} fresh matter, if conducted as a three-week batch process. A specific methane yield performance of 0.34 m{sup 3}kg{sup -1} VS is attained, as with dry anaerobic digestion of maize silage, with the standard wet process. (orig.)

  11. Optimization of the operation of the anaerobic digestion in a water treatment plant; Optimizacion de la explotacion de la digestion anaerobia en una EDAR

    Energy Technology Data Exchange (ETDEWEB)

    Minguez Gabina, R.

    2002-07-01

    Nowadays the companies demand an optimization of the operation in an anaerobic digestion facility in a water treatment plant. Up to now, the practice of this operation has been made controlling the internal parameters of the digester experimentally. The delay in the application of the corrections is enough to decrease the performances. Thanks to the investigation carried out in the water treatment plants of Lleida an Granollers, we conclude that the most secure way to drive the anaerobic digester is to manage a strict control of the inlet parameters into digestion process. (Author)

  12. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-01

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

  13. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure.

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-22

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

  14. Identifying anaerobic digestion models using simultaneous batch experiments

    Energy Technology Data Exchange (ETDEWEB)

    Flotats, X.; Palatsi, J.; Fernandez, B.; Colomer, M. A.; Illa, J.

    2009-07-01

    As in other wastewater treatment processes, anaerobic digestion models have become a valuable tool to increase the understanding of complex biodegradation processes, to teach and to communicate using a common language, to optimize design plants and operating strategies and for trying operators and process engineers. Models require accurate and significant parameter values for being useful. (Author) 2 refs.

  15. Anaerobic biodegradation of estrogens-hard to digest

    NARCIS (Netherlands)

    Mes, de T.Z.D.; Kujawa, K.; Zeeman, G.; Lettinga, G.

    2008-01-01

    Although many publications are available on the fate of estrone (E1), 17b-estradiol (E2) and 17a-ethynylestradiol (EE2) during aerobic wastewater treatment, little is published on their fate under strictly anaerobic conditions. Present research investigated the digestibility of E1 and EE2, using dig

  16. Feasibility assessment tool for urban anaerobic digestion in developing countries

    NARCIS (Netherlands)

    Lohri, C.R.; Rodic-Wiersma, L.; Zurbrügg, C.

    2013-01-01

    This paper describes a method developed to support feasibility assessments of urban anaerobic digestion (AD). The method not only uses technical assessment criteria but takes a broader sustainability perspective and integrates technical-operational, environmental, financial-economic, socio-cultural,

  17. INCREASE OF INDICATOR ORGANISMS FOLLOWING ANAEROBIC DIGESTION AND CENTRIFUGE DEWATERING.

    Science.gov (United States)

    The Water Environment Research Foundation (WERF) recently published a report titled “Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges”. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bac...

  18. Anaerobic Digestion. Instructor's Guide. Biological Treatment Process Control.

    Science.gov (United States)

    Carnegie, John W., Ed.

    This instructor's guide contains materials needed to teach a four-lesson unit on anaerobic digestion control. These materials include: (1) unit overview; (2) lesson plans; (3) lecture outlines; (4) student worksheets for each lesson (with answers); and (5) two copies of a final quiz (with and without answers). Lesson 1 is a review of the theory of…

  19. 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...

  20. Anaerobic Digestion Analysis. Training Module 5.120.2.77.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with alkalinity, volatile acids and carbon dioxide determinations for an anaerobic sludge digester. Included are objectives, instructor guides, student handouts and transparency masters. This module considers total and bicarbonate…

  1. INCREASE OF INDICATOR ORGANISMS FOLLOWING ANAEROBIC DIGESTION AND CENTRIFUGE DEWATERING.

    Science.gov (United States)

    The Water Environment Research Foundation (WERF) recently published a report titled “Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges”. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bac...

  2. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  3. Phosphorus uptake by potato from fertilizers recovered from anaerobic digestion

    Science.gov (United States)

    Field experiments were conducted in the Columbia Basin of South Central Washington to assess the yield of potato (Solanum tuberosum) in response to application of phosphorus enriched materials recovered from anaerobic digestion of manure. The treatments were comprised of four rates (0, 56, 112 and ...

  4. Anaerobic digestion of cassava starch factory effluent.

    Science.gov (United States)

    Manilal, V B; Narayanan, C S; Balagopalan, C

    1990-06-01

    Biomethanation of cassava starch factory effluent in a batch digester produced 130 l biogas/kg dry matter with an average melthane content of 59%. About 63% COD was removed during 60 days. In semicontinuous digesters, gas production was 3251/kg dry matter with a retention time of 33,3 days giving a COD reduction of 50%. Size of starter inoculum was important for good biogasification of the effluent.

  5. An innovative bioelectrochemical-anaerobic digestion-coupled system for in-situ ammonia recovery and biogas enhancement: process performance and microbial ecology

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g......-N/L(CSTR)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m2 was produced (10 Ω). Both current driven NH4+ migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMRC...

  6. Stability and Uniform Boundedness for a Class of Anaerobic Digestion Ecological Models

    Institute of Scientific and Technical Information of China (English)

    LI Ming-qi

    2004-01-01

    Stability, boundedness and persistence are three important aspects for an ecological model. In this paper, a further analysis ora class of anaerobic digestion ecological models is performed.Based on the Liupunov Method, the local stability of all equilibria in the system is got. According to the vector fields described by the system, the proof of the boundedness of the solution on the anaerobic digestion processes is completed in three steps. The method proposed in the discussion on the boundedness can be generalized to the similar problems. Results in this paper give information on how to run the ecological system well by adjusting the system parameters.

  7. Anaerobic digestion for sustainable development: a natural approach

    Energy Technology Data Exchange (ETDEWEB)

    Gijzen, H.J.

    2002-07-01

    After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These ''natural reactors'' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic post-treatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. In conclusion: a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery. (author)

  8. Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2014-07-01

    Full Text Available Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days < Escherichia coli sp. (62 days < Salmonella sp. (133 days from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure, respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

  9. Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).

    Science.gov (United States)

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

    2014-07-14

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

  10. Evaluation of Biogas Production Performance and Archaeal Microbial Dynamics of Corn Straw during Anaerobic Co-Digestion with Cattle Manure Liquid.

    Science.gov (United States)

    Zhang, Benyue; Zhao, Hongyan; Yu, Hairu; Chen, Di; Li, Xue; Wang, Weidong; Piao, Renzhe; Cui, Zongjun

    2016-04-28

    The rational utilization of crop straw as a raw material for natural gas production is of economic significance. In order to increase the efficiency of biogas production from agricultural straw, seasonal restrictions must be overcome. Therefore, the potential for biogas production via anaerobic straw digestion was assessed by exposing fresh, silage, and dry yellow corn straw to cow dung liquid extract as a nitrogen source. The characteristics of anaerobic corn straw digestion were comprehensively evaluated by measuring the pH, gas production, chemical oxygen demand, methane production, and volatile fatty acid content, as well as applying a modified Gompertz model and high-throughput sequencing technology to the resident microbial community. The efficiency of biogas production from fresh straw (433.8 ml/g) was higher than that of production from straw silage and dry yellow straw (46.55 ml/g and 68.75 ml/g, respectively). The cumulative biogas production from fresh straw, silage straw, and dry yellow straw was 365 l(-1) g(-1) VS, 322 l(-1) g-1 VS, and 304 l(-1) g(-1) VS, respectively, whereas cumulative methane production was 1,426.33%, 1,351.35%, and 1,286.14%, respectively, and potential biogas production was 470.06 ml(-1) g(-1) VS, 461.73 ml(-1) g(-1) VS, and 451.76 ml(-1) g(-1) VS, respectively. Microbial community analysis showed that the corn straw was mainly metabolized by acetate-utilizing methanogens, with Methanosaeta as the dominant archaeal community. These findings provide important guidance to the biogas industry and farmers with respect to rational and efficient utilization of crop straw resources as material for biogas production.

  11. 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.

  12. A bio-electrochemical system for removing inhibitors of anaerobic digestion processes from anaerobic reactors

    DEFF Research Database (Denmark)

    2014-01-01

    Inhibition of anaerobic digestion process by high level of ammonia (NH4 +/I\\IH3) is the most serious problem existing in biogas plants. No viable/applicable method to overcome this problem has been found up to now. This invention proposes an innovative submersible bio-electrochemical membrane...... reactor to recover ammonia from anaerobic digestion reactor, and thereby alleviate or counteract ammonia inhibition and enhance the conversion of ammonia-rich wastes to biogas. The invention may further reduce overall cost, giving synergistic advantages for both ammonia recycling and biogas plants...

  13. Anaerobic Digestion I. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

    Science.gov (United States)

    Arasmith, E. E.

    This lesson is the first of a two-part series on anaerobic digestion. Topics discussed include the five basic functions of an anaerobic digester, basic theory of the biological processes involved, basic equipment necessary for digestion, and the products of digestion. The lesson includes an instructor's guide and student workbook. The instructor's…

  14. Anaerobic digestion as final step of a cellulosic ethanol biorefinery:

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Ahring, Birgitte Kiær

    2010-01-01

    In order to lower the costs for second generation bioethanol from lignocellulosic biomass anaerobic digestion of the effluent from ethanol fermentation was implemented using an upflow anaerobic sludge blanket (UASB) reactor system in a pilot-scale biorefinery plant. Both thermophilic (538C...... were, however, higher under mesophilic conditions compared to thermophilic conditions. The conversion of dissolved organic matter (VSdiss) was between 68% and 91%. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. However, a high content...... of suspended matter reduced the degradation efficiency. The retention time of the anaerobic system could be reduced from 70 to 7 h by additional removal of suspended matter by clarification. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher carbon utilization...

  15. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    NARCIS (Netherlands)

    Mashad, El H.; Zeeman, G.; Loon, van W.K.P.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    The influence of temperature, 50 and 60 °C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fl

  16. 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...

  17. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    NARCIS (Netherlands)

    Mashad, El H.; Zeeman, G.; Loon, van W.K.P.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    The influence of temperature, 50 and 60 °C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature

  18. CFD simulation of non-Newtonian fluid flow in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin; Chen, Shulin

    2008-02-15

    A general mathematical model that predicts the flow fields in a mixed-flow anaerobic digester was developed. In this model, the liquid manure was assumed to be a non-Newtonian fluid, and the flow governed by the continuity, momentum, and k-epsilon standard turbulence equations, and non-Newtonian power law model. The commercial computational fluid dynamics (CFD) software, Fluent, was applied to simulate the flow fields of lab-scale, scale-up, and pilot-scale anaerobic digesters. The simulation results were validated against the experimental data from literature. The flow patterns were qualitatively compared for Newtonian and non-Newtonian fluids flow in a lab-scale digester. Numerical simulations were performed to predict the flow fields in scale-up and pilot-scale anaerobic digesters with different water pump power inputs and different total solid concentration (TS) in the liquid manure. The optimal power inputs were determined for the pilot-scale anaerobic digester. Some measures for reducing dead and low velocity zones were proposed based upon the CFD simulation results.

  19. 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.

  20. 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.

  1. Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

    Science.gov (United States)

    Batstone, D J; Torrijos, M; Ruiz, C; Schmidt, J E

    2004-01-01

    The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter

  2. The role of anaerobic digestion in the emerging energy economy.

    Science.gov (United States)

    Batstone, Damien John; Virdis, Bernardino

    2014-06-01

    Anaerobic digestion is the default process for biological conversion of residue organics to renewable energy and biofuel in the form of methane. However, its scope of application is expanding, due to availability of new technologies, and the emerging drivers of energy and nutrient conservation and recovery. Here, we outline two of these new application areas, namely wastewater nutrient and energy recovery, and generation of value added chemicals through mixed culture biotechnology. There exist two options for nutrient and energy recovery from domestic wastewater: low energy mainline and partition-release-recovery. Both are heavily dependent on anaerobic digestion as an energy generating and nutrient release step, and have been enabled by new technologies such as low emission anaerobic membrane processes. The area of mixed culture biotechnology has been previously identified as a key industrial opportunity, but is now moving closer to application due application of existing and new technologies. As well as acting as a core technology option in bioproduction, anaerobic digestion has a key role in residual waste valorization and generation of energy for downstream processing. These new application areas and technologies are emerging simultaneously with substantial advances in knowledge of underlying mechanisms such as electron transfer, understanding of which is critical to development of the new application areas.

  3. 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.

  4. Anaerobic digestion of solid biomass and biowaste

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Within the International Trade Fair for Biogas Plant Technology from 23rd to 24th February, 2012 in Berlin, the following lectures were held: (1) Presentation and results of the EU project 24biomass'' (Claudia Lutsyuk); (2) The Polish biogas market (Tomasz Surowiec); (3) Presence and future of the biogas sector in Poland - EBE project (Eugeniusz Jedrysik); (4) Modern biogas generation in Poland - Case studies of the company Poldanor (Jens Bo Holm-Nielsen); (5) Low space requirement - The challenge in the integration of biogas plants in existing composting facilities - examples from real life (Michael Oertig); (6) Integration of biogas plants in composting facilities by partial-flow fermentation (Bruno Mattheeuws); (7) The significance of an efficient removal of foreign matter from biomass before fermentation in a waste incinerator for municipal wastes (Stephan Schulte); (8) Sustainable enhancement of the anaerobic degradation and increase of the biogas production by means of ultrasonic treatment - examples from real life (Silvana Velten); (9) Cultivation of energy plants on sandy soils in the northeastern part of Germany (Gunter Ebel); (10) Topinambur, a new sustainable energy crop for biogas generation (Vito Pignatelli); (11) Potential of biogas generation from reed (Vilis Dubrovskis); (12) Biogas generation from maize straw - a new procedure of harvesting and processing (Thomas Amon); (13) Generation of biogas by cofermentation of pig manure and grass silage: a pilot study (Ximmin Zhan); (14) Thermophilic dry fermentation of poultry litter and energy crops for the generation of biogas, organic fertilizer and protection of water resources from environmental damages in the Mid-Atlantic region of the USA (John Intersoll); (15) Energetic utilisation of horse manure (Saskia Oldenburg); (16) Realization of the greatest and most modern Hungarian biogas plant in Szarvas (Ludwig Dinkloh); (16) Biogas in Russia - The investment program of the cooperation &apos

  5. Anaerobic digestion of pulp and paper mill wastewater and sludge.

    Science.gov (United States)

    Meyer, Torsten; Edwards, Elizabeth A

    2014-11-15

    Pulp and paper mills generate large amounts of waste organic matter that may be converted to renewable energy in form of methane. The anaerobic treatment of mill wastewater is widely accepted however, usually only applied to few selected streams. Chemical oxygen demand (COD) removal rates in full-scale reactors range between 30 and 90%, and methane yields are 0.30-0.40 m(3) kg(-1) COD removed. Highest COD removal rates are achieved with condensate streams from chemical pulping (75-90%) and paper mill effluents (60-80%). Numerous laboratory and pilot-scale studies have shown that, contrary to common perception, most other mill effluents are also to some extent anaerobically treatable. Even for difficult-to-digest streams such as bleaching effluents COD removal rates range between 15 and 90%, depending on the extent of dilution prior to anaerobic treatment, and the applied experimental setting. Co-digestion of different streams containing diverse substrate can level out and diminish toxicity, and may lead to a more robust microbial community. Furthermore, the microbial population has the ability to become acclimated and adapted to adverse conditions. Stress situations such as toxic shock loads or temporary organic overloading may be tolerated by an adapted community, whereas they could lead to process disturbance with an un-adapted community. Therefore, anaerobic treatment of wastewater containing elevated levels of inhibitors or toxicants should be initiated by an acclimation/adaptation period that can last between a few weeks and several months. In order to gain more insight into the underlying processes of microbial acclimation/adaptation and co-digestion, future research should focus on the relationship between wastewater composition, reactor operation and microbial community dynamics. The potential for engineering and managing the microbial resource is still largely untapped. Unlike in wastewater treatment, anaerobic digestion of mill biosludge (waste activated

  6. Intermediate-scale high-solids anaerobic digestion system operational development

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J.

    1995-02-01

    Anaerobic bioconversion of solid organic wastes represents a disposal option in which two useful products may be produced, including a medium Btu fuel gas (biogas) and a compost-quality organic residue. The application of high-solids technology may offer several advantages over conventional low-solids digester technology. Operation of the anaerobic digestion process at high solids reduces the level of process water and thereby the size and capital costs for the digester system. In addition, by virtue of the lack of available water, the microbial catalysts are more productive in feedstock polymer hydrolysis. The National Renewable Energy Laboratory (NREL) has developed a unique digester system capable of uniformly mixing high-solids materials at low cost. Information gained from laboratory-scale digester research was used to develop die intermediate-scale digester system. This system represents a 50-fold scale-up of the original digester system and includes continuous feed addition and computer monitoring and control. During the first 1.15 years of operation, a variety of modifications and improvements were instituted to increase the safety, reliability, and performance of the system. Those improvements -- which may be critical in further scale-up efforts using the NREL high-solids digester design -- are detailed in this report.

  7. 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.

  8. Anaerobic digestion of pig manure and glycerol from biodiesel production

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh, Sumate Chaiprapat, Chaisri Suksaroj

    2015-01-01

    Full Text Available Increasing biodiesel production causes a surplus of glycerol. This work aims to investigate the crude glycerol pretreatment method and then apply the glycerol as a co-substrate with pig manure for anaerobic digestion. The optimum crude glycerol pretreatment method was acidification with 6% of H2SO4 that highest glycerol recovery was obtained with lowest cost. Co-digestions of glycerol and pig manure enhanced biogas and methane productions compared with mono-digestions. Biogas and methane productions in semi-continuous digestions were highly effected by OLR. The optimum OLR was 3.06 kg SCOD/m3 that biogas production was maintained at 3 L/d with methane composition of 72% and SCOD removal higher than 80%.

  9. Reduction in greenhouse gas emissions from vinasse through anaerobic digestion

    DEFF Research Database (Denmark)

    Moraes, Bruna S.; Petersen, Søren O.; Zaiat, Marcelo

    2017-01-01

    , and from fertirrigated soils. This study assessed GHG emissions in experiments simulating this vinasse management system, and the potential for reducing emissions of methane (CH4) and nitrous oxide (N2O) from vinasse via anaerobic digestion (AD) in biogas plants. During 21 days’ storage of untreated...... vinasse, 29% of dry matter (DM) and 40% of volatile solids (VS) were lost, which resulted in cumulative CH4 emissions of up to 43.8 kg CO2eq kg−1 C-vinasse. In contrast, there were no CH4 emissions from AD-treated vinasse (digestate) during storage. GHG emission was related to the biochemical...... characteristics of the untreated and digested vinasse. The accumulation of oxidised nitrogen (N) compounds was up to four-fold higher in soil amended with untreated vinasse than from digestate-amended soil. The N2O emissions from soil amended with untreated vinasse were also higher than from soil amended...

  10. 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.

  11. [Distribution and removal of anaerobic antibiotic resistant bacteria during mesophilic anaerobic digestion of sewage sludge].

    Science.gov (United States)

    Tong, Juan; Wang, Yuan-Yue; Wei Yuan, Song

    2014-10-01

    Sewage sludge is one of the major sources that releasing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) into the environment since it contains large amount of ARB, but there is little information about the fate of the anaerobic ARB in the anaerobic digestion of sewage sludge. Therefore, the distribution, removal and seasonal changes of tetracycline and β-lactam antibiotics resistant bacteria in the mesophilic egg-shaped digesters of a municipal wastewater treatment plant were investigated for one year in this study. Results showed that there were higher amounts of ARB and higher resistance rate of β-lactam antibiotics than that of tetracycline antibiotics in the sewage sludge. All ARB could be significantly reduced during the mesophilic anaerobic digestion process by 1.48-1.64 log unit (P resistance rates were significantly increased after anaerobic digestion by 12.0% and 14.3%, respectively (P change characteristics. Except for chlorotetracycline resistant bacteria, there were more ARB in the sewage sludge in cold season than in warm season (P < 0.05).

  12. Hydrogen production from the dissolution of nano zero valent iron and its effect on anaerobic digestion.

    Science.gov (United States)

    Huang, Yu-Xi; Guo, Jialiang; Zhang, Chunyang; Hu, Zhiqiang

    2016-01-01

    Nano zero valent iron (NZVI) has shown inhibition on methanogenesis in anaerobic digestion due to its reductive decomposition of cell membrane. The inhibition was accompanied by the accumulation of hydrogen gas due to rapid NZVI dissolution. It is not clear whether and how rapid hydrogen release from NZVI dissolution directly affects anaerobic digestion. In this study, the hydrogen release kinetics from NZVI (average size = 55 ± 11 nm) dissolution in deionized water under anaerobic conditions was first evaluated. The first-order NZVI dissolution rate constant was 2.62 ± 0.26 h(-1) with its half-life of 0.26 ± 0.03 h. Two sets of anaerobic digestion experiments (i.e., in the presence of glucose or without any substrate but at different anaerobic sludge concentrations) were performed to study the impact of H2 release from rapid NZVI dissolution, in which H2 was generated in a separate water bottle containing NZVI (i.e., ex situ H2 or externally supplied from NZVI dissolution) before hydrogen gas was introduced to anaerobic digestion. The results showed that the H2 partial pressure in the headspace of the digestion bottle reached as high as 0.27 atm due to rapid NZVI dissolution, resulting in temporary inhibition of methane production. Nevertheless, the 5-d cumulative methane volume in the group with ex situ H2 production due to NZVI dissolution was actually higher than that of control, suggesting NZVI inhibition on methanogenesis is solely due to the reductive decomposition of cell membrane after direct contact with NZVI.

  13. 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.

  14. ANIMAL MANURE – REDUCED QUALITY BY ANAEROBIC DIGESTION?

    DEFF Research Database (Denmark)

    Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun

    2014-01-01

    Anaerobic digestion may reduce emissions of greenhouse gases, but we know little about its impact on soil fertility. Reduced concentrations of easily degradable C in the manure may imply less food for the soil fauna and microflora. A field experiment to study its effect on crop yields and soil...... caused the death of both surface-dwelling and soil-living earthworms shortly after application, but the long-term effect of manure application seemed more positive, especially at low application levels. So far, we have observed only small differences in the effects of digested and undigested manure...

  15. Anaerobic digestion of manure - consequences for plant production

    DEFF Research Database (Denmark)

    Løes, Anne-Kristin; Pommeresche, Reidun; Johansen, Anders

    2013-01-01

    Organic farming systems are today dependent upon fossil energy. Another challenge are soil nutrient concentrations, which may be depleted with time even in animal husbandry systems (Løes & Øgaard 2001). Anaerobic digestion (AD) of animal manure may produce biogas to replace fossil fuels, and reduce...... methane (CH4) emissions during manure storage. Co-digestion of substrates rich in energy increases the economic viability of the biogas plant, and off-farm substrates such as fish silage or household waste may add nutrients to the farming system. AD may also ease manure handling, while reducing the amount...

  16. Modeling of two-phase anaerobic process treating traditional Chinese medicine wastewater with the IWA Anaerobic Digestion Model No. 1.

    Science.gov (United States)

    Chen, Zhaobo; Hu, Dongxue; Zhang, Zhenpeng; Ren, Nanqi; Zhu, Haibo

    2009-10-01

    The aim of the study was to implement a mathematical model to simulate two-phase anaerobic digestion (TPAD) process which consisted of an anaerobic continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket (UASB) reactor in series treating traditional Chinese medicine (TCM) wastewater. A model was built on the basis of Anaerobic Digestion Model No. 1 (ADM1) while considering complete mixing model for the CSTR, and axial direction discrete model and mixed series connection model for the UASB. The mathematical model was implemented with the simulation software package MATLABTM/Simulinks. System performance, in terms of COD removal, volatile fatty acids (VFA) accumulation and pH fluctuation, was simulated and compared with the measured values. The simulation results indicated that the model built was able to well predict the COD removal rate (-4.8-5.0%) and pH variation (-2.9-1.4%) of the UASB reactor, while failed to simulate the CSTR performance. Comparing to the measured results, the simulated acetic acid concentration of the CSTR effluent was underpredicted with a deviation ratios of 13.8-23.2%, resulting in an underprediction of total VFA and COD concentrations despite good estimation of propionic acid, butyric acid and valeric acid. It is presumed that ethanol present in the raw wastewater was converted into acetic acid during the acidification process, which was not considered by the model. Additionally, due to the underprediction of acetic acid the pH of CSTR effluent was overestimated.

  17. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    Volatile fatty acid (VFA) concentration is known as an important indicator to control and optimize anaerobic digestion (AD) process. In this study, an innovative VFA biosensor was developed based on the principle of a microbial desalination cell. The correlation between current densities and VFA...... concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities and VFA levels from 1 to 30 mM (0.04 to 8.50 mA/m2, R2=0.97) and then from 30 to 200 mM (8.50 to 10.80 mA/m2, R2=0.95). The detection range was much broader than that of other existing...... and reliable measurement of VFA levels during AD and other anaerobic processes....

  18. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    Volatile fatty acid (VFA) concentration is known as an important indicator to control and optimize anaerobic digestion (AD) process. In this study, an innovative VFA biosensor was developed based on the principle of a microbial desalination cell. The correlation between current densities and VFA...... concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities and VFA levels from 1 to 30 mM (0.04 to 8.50 mA/m2, R2=0.97) and then from 30 to 200 mM (8.50 to 10.80 mA/m2, R2=0.95). The detection range was much broader than that of other existing...... and reliable measurement of VFA levels during AD and other anaerobic processes....

  19. Biodegradability of wastewater and activated sludge organics in anaerobic digestion.

    Science.gov (United States)

    Ikumi, D S; Harding, T H; Ekama, G A

    2014-06-01

    The investigation provides experimental evidence that the unbiodegradable particulate organics fractions of primary sludge and waste activated sludge calculated from activated sludge models remain essentially unbiodegradable in anaerobic digestion. This was tested by feeding the waste activated sludge (WAS) from three different laboratory activated sludge (AS) systems to three separate anaerobic digesters (AD). Two of the AS systems were Modified Ludzack - Ettinger (MLE) nitrification-denitrification (ND) systems and the third was a membrane University of Cape Town (UCT) ND and enhanced biological P removal system. One of the MLE systems and the UCT system were fed the same real settled wastewater. The other MLE system was fed raw wastewater which was made by adding a measured constant flux (gCOD/d) of macerated primary sludge (PS) to the real settled wastewater. This PS was also fed to a fourth AD and a blend of PS and WAS from settled wastewater MLE system was fed to a fifth AD. The five ADs were each operated at five different sludge ages (10-60d). From the measured performance results of the AS systems, the unbiodegradable particulate organic (UPO) COD fractions of the raw and settled wastewaters, the PS and the WAS from the three AS systems were calculated with AS models. These AS model based UPO fractions of the PS and WAS were compared with the UPO fractions calculated from the performance results of the ADs fed these sludges. For the PS, the UPO fraction calculated from the AS and AD models matched closely, i.e. 0.30 and 0.31. Provided the UPO of heterotrophic (OHO, fE_OHO) and phosphorus accumulating (PAO, fE_PAO) biomass were accepted to be those associated with the death regeneration model of organism "decay", the UPO of the WAS calculated from the AS and AD models also matched well - if the steady state AS model fE_OHO = 0.20 and fE_PAO = 0.25 values were used, then the UPO fraction of the WAS calculated from the AS models deviated significantly

  20. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.

    1982-08-01

    The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

  1. Temperature Control of a Pilot Anaerobic Digestion Reactor

    Directory of Open Access Journals (Sweden)

    Finn Haugen

    2013-07-01

    Full Text Available Results of analysis and design and implementation of a temperature controlsystem for a practical pilot anaerobic digestion (AD bioreactor fed with dairywaste are presented. A dynamic model of the reactor temperature is used asthe basis for theoretical results, including simulations. Controller functionsinclude on-off control, proportional plus integral (PI control, andfeedforward control. Various PI controller tuning methods are compared. Theneed for adaptivity of PI settings is investigated. Results for asimulated full-scale reactor are given.

  2. Fault detection filter design for an anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Aubrun, C.; Garnier, O. [Univ. Henri Poincare - Nancy 1, Vandoeuvre (France); Harmand, J.; Steyer, J.P. [LBE-INRA, Narbonne (France)

    2000-05-01

    In this paper, a Fault Detection and Isolation observer based method has been applied to biological wastewater treatment process. The method is designed with a dynamic model and the observer is determined using the eigenstructure assignment approach. The efficiency of the method is demonstrated for both detection and isolation of an actuator and a sensor failure using experimental data from a pilot scale anaerobic digestion process for the treatment of an industrial wine distillery vinasses. (orig.)

  3. Development of the Laboratory Anaerobic Bioreactor for Wet and Dry Digestion Processes

    Directory of Open Access Journals (Sweden)

    Rusín Jiří

    2016-12-01

    Full Text Available This article presents partial results of the laboratory development of an anaerobic bioreactor designed for the physical modelling of (semicontinuous dry or wet anaerobic digestion processes. A horizontal cylindrical tank reactor of 0.4 m3 total capacity has been developed. The reactor allows the continuous stirring of a liquid batch or the intermittent stirring of a solid batch. The bioreactor has been used as a lab-scale digestor in the research project dealing with high-solids (dry anaerobic co-digestion organic fraction of mixed municipal solid waste. The first experiment was performed on the mixture of MSW with corn silage (1:1 with the weight of 300 kg.

  4. Thermophilic anaerobic digestion of coffee grounds with and without waste activated sludge as co-substrate using a submerged AnMBR: system amendments and membrane performance.

    Science.gov (United States)

    Qiao, Wei; Takayanagi, Kazuyuki; Shofie, Mohammad; Niu, Qigui; Yu, Han Qing; Li, Yu-You

    2013-12-01

    Coffee grounds are deemed to be difficult for degradation by thermophilic anaerobic process. In this research, a 7 L AnMBR accepting coffee grounds was operated for 82 days and failed with pH dropping to 6.6. The deficiency of micronutrients in the reactor was identified. The system was recovered by supplying micronutrient, pH adjustment and influent ceasing for 22 days. In the subsequent 160 days of co-digestion experiment, waste activated sludge (15% in the mixture) was mixed into coffee grounds. The COD conversion efficiency of 67.4% was achieved under OLR of 11.1 kg-COD/m(3) d and HRT of 20 days. Tannins was identified affecting protein degradation by a batch experiment. Quantitative supplements of NH4HCO3 (0.12 g-N/g-TSin) were effective to maintain alkalinity and pH. The solid concentration in the AnMBR reached 75 g/L, but it did not significantly affect membrane filtration under a flux of 5.1 L/m(2) h. Soluble carbohydrate, lipid and protein were partially retained by the membrane. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Semi-continuous anaerobic co-digestion of sugar beet byproduct and pig manure: Effect of the organic loading rate (OLR) on process performance.

    Science.gov (United States)

    Aboudi, Kaoutar; Álvarez-Gallego, Carlos José; Romero-García, Luis Isidoro

    2015-10-01

    Anaerobic co-digestion of dried pellet of exhausted sugar beet cossettes (ESBC-DP) with pig manure (PM) was investigated in a semi-continuous stirred tank reactor (SSTR) under mesophilic conditions. Seven hydraulic retention times (HRT) from 20 to 5 days were tested with the aim to evaluate the methane productivities and volatile solids (VS) removal. The corresponding organic loading rates (OLR) ranged from 4.2 to 12.8 gVS/L(reactor) d. The findings revealed that highest system efficiency was achieved at an OLR of 11.2 gVS/L(reactor) d (6 days-HRT) with a methane production rate (MPR) and volatile solids (VS) reduction of 2.91 LCH4/L(reactor) d and 57.5%, respectively. The HRT of 5 days was found critical for the studied process, which leads to volatile fatty acids (VFA) accumulation and sharp drop in pH. However, the increase of HRT permits the recovery of system.

  6. Anaerobic digestion of microalgal biomass: Challenges, opportunities and research needs.

    Science.gov (United States)

    Gonzalez-Fernandez, Cristina; Sialve, Bruno; Molinuevo-Salces, Beatriz

    2015-12-01

    Integration of anaerobic digestion (AD) with microalgae processes has become a key topic to support economic and environmental development of this resource. Compared with other substrates, microalgae can be produced close to the plant without the need for arable lands and be fully integrated within a biorefinery. As a limiting step, anaerobic hydrolysis appears to be one of the most challenging steps to reach a positive economic balance and to completely exploit the potential of microalgae for biogas and fertilizers production. This review covers recent investigations dealing with microalgae AD and highlights research opportunities and needs to support the development of this resource. Novel approaches to increase hydrolysis rate, the importance of the reactor design and the noteworthiness of the microbial anaerobic community are addressed. Finally, the integration of AD with microalgae processes and the potential of the carboxylate platform for chemicals and biofuels production are reviewed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Toxicity of nonylphenol diethoxylate in lab-scale anaerobic digesters

    DEFF Research Database (Denmark)

    Bozkurt, Hande; Sanin, F. Dilek

    2014-01-01

    . Their widespread use and disposal cause them to enter wastewater treatment systems at high concentrations. Since they are highly persistent and hydrophobic, they accumulate mostly on sludge.In this study using Anaerobic Toxicity Assay (ATA) tests, the toxicity of a model nonylphenol compound, nonylphenol...... diethoxylate (NP2EO), for anaerobic digestion of sludge was determined. The test bottles were dosed with NP2EO in acetone, with concentrations ranging from 1mgL-1 to 30mgL-1. During the tests, gas productions and compositions in terms of methane and carbon dioxide were monitored. To be able to judge about...... seen in NP1EO and NP and further accumulation of NP in the system, indicated the conversion of NP2EO to these metabolites. On the other hand, no conversion was observed in abiotic reactors. Inhibition of NP2EO for anaerobic microorganisms was not observed throughout the tests considering the biogas...

  8. 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.

  9. Treatment of melanoidin wastewater by anaerobic digestion and coagulation.

    Science.gov (United States)

    Arimi, Milton M; Zhang, Yongjun; Götz, Gesine; Geißen, Sven-Uwe

    2015-01-01

    Melanoidins are dark-coloured recalcitrant pollutants found in many industrial wastewaters including coffee-manufacturing effluent, molasses distillery wastewater (MDWW) and other wastewater with molasses as the raw material. The wastewaters are mostly treated with anaerobic digestion after some dilution to minimize the inhibition effect. However, the dark colour and recalcitrant dissolved organic carbon (DOC) mainly caused by melanoidin are not effectively removed. The aim of this study was to investigate the removal of colour and remnant DOC by different coagulants from anaerobically digested MDWW. From the six coagulants tested, ferric chloride had the highest melanoidin (48%), colour (92.7%) and DOC (63.3%) removal at pH 5 and a dosage of 1.6 g/l. Both polymer and inorganic salt coagulants tested had optimal colour, melanoidin and DOC removal at acidic pH. The molecular size distribution of synthetic melanoidins by liquid chromatography-organic carbon detection indicated a preferential removal of high-molecular-weight melanoidins over low weight melanoidins by the coagulation. Further studies should focus on how to improve biodegradability of the treated effluent for it to be reused as dilution water for anaerobic digestion.

  10. Modelling sodium inhibition on the anaerobic digestion process.

    Science.gov (United States)

    Hierholtzer, A; Akunna, J C

    2012-01-01

    Sodium is a known process inhibitor in anaerobic systems and impacts on methanogens through an increase of osmotic pressure or complete dehydration of microorganisms. In this study, a combination of experimental and modelling approaches has been employed to determine and simulate sodium inhibition on the anaerobic digestion process. The ADM1, which has been successfully used in modelling anaerobic processes, has been modified to include an extra inhibition function that considers the effect of sodium on acetoclastic methanogens and the impact on biogas production and composition. A non-competitive inhibition function was added to the rate of acetate uptake for the model to take into account sodium toxicity. Experimental studies consisted of both batch and reactor tests to obtain parameters for model calibration and validation. The calibrated model was used to predict the effect of ammonia nitrogen on sodium toxicity. It was found that relatively low sodium levels can bring about significant levels of process inhibition in the presence of high levels of ammonia. On the other hand, where the concentration of ammonia is relatively low, the tolerance threshold for sodium ions increases. Hence, care must be taken in the use of sodium hydroxide for pH adjustment during anaerobic digestion of protein-rich substrates.

  11. Trace elements induce predominance among methanogenic activity in anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Babett Wintsche

    2016-12-01

    Full Text Available Trace elements play an essential role in all organisms due to their functions in enzyme complexes. In anaerobic digesters, control and supplementation of trace elements lead to stable and more efficient methane production processes while trace element deficits cause process imbalances. However, the underlying metabolic mechanisms and the adaptation of the affected microbial communities to such deficits are not yet fully understood. Here, we investigated the microbial community dynamics and resulting process changes induced by trace element deprivation. Two identical lab-scale continuous stirred tank reactors fed with distiller’s grains and supplemented with trace elements (cobalt, molybdenum, nickel, tungsten and a commercial iron additive were operated in parallel. After 72 weeks of identical operation, the feeding regime of one reactor was changed by omitting trace element supplements and reducing the amount of iron additive. Both reactors were operated for further 21 weeks. Various process parameters (biogas production and composition, total solids and volatile solids, trace element concentration, volatile fatty acids, total ammonium nitrogen, total organic acids/alkalinity ratio, and pH and the composition and activity of the microbial communities were monitored over the total experimental time. While the methane yield remained stable, the concentrations of hydrogen sulfide, total ammonia nitrogen, and acetate increased in the trace element-depleted reactor compared to the well-supplied control reactor. Methanosarcina and Methanoculleus dominated the methanogenic communities in both reactors. However, the activity ratio of these two genera was shown to depend on trace element supplementation explainable by different trace element requirements of their energy conservation systems. Methanosarcina dominated the well-supplied anaerobic digester, pointing to acetoclastic methanogenesis as the dominant methanogenic pathway. Under trace element

  12. A full-scale study of mixing and foaming in egg-shaped anaerobic digesters.

    Science.gov (United States)

    Subramanian, Bhargavi; Miot, Alexandre; Jones, Bonnie; Klibert, Corey; Pagilla, Krishna R

    2015-09-01

    Seasonal foaming in full-scale egg-shaped digesters (ESD) at the Oceanside Water Pollution Control Plant was investigated over a two-year period. The causes and contributors of anaerobic digestion (AD) foaming, namely, Gordonia amarae filaments and mixing effects were evaluated in these ESDs. The seasonal presence of high levels of G. amarae as a primary cause and excessive induced mixing as an important contributor of AD foaming has been established. The induced mixing frequency in the ESDs was gradually reduced and eventually shut off in a series of controlled experimental phases. Total solids and temperature profiles indicated that reducing mixing frequency did not significantly impact digester performance or disrupt the homogeneity of digester contents, although it did reduce the occurrence of foam in the digesters. Excessive induced mixing, a contributor to foaming, increased foam events at G. amarae thresholds above 10(6)intersections/mg VSS in the mixed liquor.

  13. Recovery of methane-rich gas from solid-feed anaerobic digestion of ipomoea (Ipomoea carnea).

    Science.gov (United States)

    Sankar Ganesh, P; Sanjeevi, R; Gajalakshmi, S; Ramasamy, E V; Abbasi, S A

    2008-03-01

    Studies are presented on new types of anaerobic digesters in which chopped or dry crushed Ipomoea carnea was fed without any other pretreatment, in an attempt to develop commercially viable means of utilizing the otherwise very harmful plant. Two types of solid-feed anaerobic digesters (SFADs) were studied. The first type had a single vessel in which the bottom 35% portion was separated from the top portion by a perforated PVC disk. The weed was charged from the top and inoculated with anaerobically digested cowdung-water slurry. The fermentation of the weed in the reactor led to the formation of volatile fatty acids (VFAs) plus some biogas. The leachate, rich in the VFAs, was passed through the perforated PVC sheet and collected in the lower portion of the vessel. The other type of reactors had two vessels, the first one was fully charged with the weed and the second received the VFA leachate. With both types were attached upflow anaerobic filters (UAFs) which converted the leachate into combustible biogas consisting of approximately 70% methane. All SFADs developed very consistent performance in terms of biogas yield within 17 weeks of start. The two-compartment reactors yielded significantly more biogas than the single-compartment reactors of corresponding total volume, and the reactors with which anaerobic filters (AF) were attached yielded more biogas than the ones without AF. The best performing units generated 2.41m(3) of biogas per m(3) of digester volume, as compared to 0.1-0.2m(3) of biogas, m(-3)d(-1), obtainable with conventional digesters. This indicates the viability of this technology. The spent weed can be vermicomposted directly to obtain good soil-conditioner cum fertilizer; earthworm Eudrilus eugeniae produced 540mg vermicast per animal every day, achieving near total conversion of feed to vermicast in 20 days. The proposed systems, thus, makes it possible to accomplish total utilization of ipomoea.

  14. Model-based predictions of anaerobic digestion of agricultural substrates for biogas production.

    Science.gov (United States)

    Zhou, Haidong; Löffler, Daniel; Kranert, Martin

    2011-12-01

    A modified Anaerobic Digestion Model No. 1 (ADM1), calibrated on a laboratory digester with a feeding mix of 30% weight of cow manure and 70% weight of corn silage, was implemented, showing its performances of simulation as a decision-making and planning-supporting tool for the anaerobic digestion of agricultural substrates. The virtual fermenter obtained was used to conduct simulations with different feeding compositions and loading rates of cow manure, corn silage, grass silage and rape oil. All simulations were started at the same initial state which was represented by a steady state with an organic loading rate of 2.5 kg ODM/(mdigester3∗d). The effects of the different feeding combinations on biogas composition and biogas yield were predicted reasonably, and partly verified with the available literature data. Results demonstrated that the simulations could be helpful for taking decisions on agricultural biogas plant operation or experimental set-ups, if used advisedly.

  15. Cellulose accessibility and microbial community in solid state anaerobic digestion of rape straw.

    Science.gov (United States)

    Tian, Jiang-Hao; Pourcher, Anne-Marie; Bureau, Chrystelle; Peu, Pascal

    2017-01-01

    Solid state anaerobic digestion (SSAD) with leachate recirculation is an appropriate method for the valorization of agriculture residues. Rape straw is a massively produced residue with considerable biochemical methane potential, but its degradation in SSAD remains poorly understood. A thorough study was conducted to understand the performance of rape straw as feedstock for laboratory solid state anaerobic digesters. We investigated the methane production kinetics of rape straw in relation to cellulose accessibility to cellulase and the microbial community. Improving cellulose accessibility through milling had a positive influence on both the methane production rate and methane yield. The SSAD of rape straw reached 60% of its BMP in a 40-day pilot-scale test. Distinct bacterial communities were observed in digested rape straw and leachate, with Bacteroidales and Sphingobacteriales as the most abundant orders, respectively. Archaeal populations showed no phase preference and increased chronologically. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Anaerobic digestion of linear alkyl benzene sulfonates: biodegradation kinetics and metabolite analysis.

    Science.gov (United States)

    García, M T; Campos, E; Ribosa, I; Latorre, A; Sánchez-Leal, J

    2005-09-01

    In the present work the effect of the alkyl chain length and the position of the sulfophenyl substituent of the linear alkylbenzene sulfonates (LAS) on their anaerobic biodegradability have been investigated. Degradation kinetics of the linear alkyl benzene sulfonates homologues, 2phiC10LAS, 2phiC12LAS and 2phiC14LAS, have been studied. It has been also investigated the effect of the isomer type on the degradation rate of the LAS molecule through the comparative study of the 2phiC10LAS and 5phiC10LAS isomers. Batch anaerobic biodegradation tests were performed using sludge from the anaerobic digester of a wastewater treatment plant as microorganisms source. Ultimate biodegradation was evaluated from the biogas production whereas primary biodegradation was determined by specific analysis of the surfactant. LAS homologues and isomers showed a negligible primary biodegradation under anaerobic conditions. Furthermore, analysis of sulfophenyl carboxilates (SPC) by LC-MS indicated a low and constant level of these LAS degradation metabolites over the test period. These data are consistent with a minimal transformation of the LAS parent molecule in the anaerobic digesters. On the other hand, the addition of the shortest alkyl chain length homologues, decyl and dodecylbenzene sulfonates, reduces the biogas production whereas the most hydrophobic homologue, the tetradecylbenzene sulfonate, enhances the biogas production. This LAS homologue seems to increase the availability of organic compounds sorbed on the anaerobic sludge promoting their biodegradation.

  17. Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Fermoso, F.G.; Weijma, J.; Zagt, K.; Lier, van J.B.

    2011-01-01

    Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH4 content which generally ranges between 55 and 65%. Biogas upgrading to so-called ‘green gas’, with natural gas quality, generally proceeds

  18. Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Fermoso, F.G.; Weijma, J.; Zagt, K.; Lier, van J.B.

    2011-01-01

    Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH4 content which generally ranges between 55 and 65%. Biogas upgrading to so-called ‘green gas’, with natural gas quality, generally proceeds

  19. Instrumentation and control of anaerobic digestion processes: A review and some research challenges

    NARCIS (Netherlands)

    Jimenez, J.; Latrille, E.; Harmand, J.; Robles, A.; Ferrer, J.; Gaida, D.; Wolf, C.; Mairet, F.; Bernard, O.; Alcaraz-Gonzalez, V.; Mendez-Acosta, H.; Zitomer, D.; Totzke, D.; Spanjers, H.; Jacobi, F.; Guwy, A.; Dinsdale, R.; Premier, G.; Mazhegrane, S.; Ruiz-Filippi, G.; Seco, A.; Ribeiro, T.; Pauss, A.; Steyer, J.P.

    2015-01-01

    To enhance energy production from methane or resource recovery from digestate, anaerobic digestion processes require advanced instrumentation and control tools. Over the years, research on these topics has evolved and followed the main fields of application of anaerobic digestion processes: from mun

  20. Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

    Energy Technology Data Exchange (ETDEWEB)

    Xu Fuqing; Shi Jian [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States); Lv Wen; Yu Zhongtang [Department of Animal Sciences, Ohio State University, Columbus, OH 43210 (United States); Li Yebo, E-mail: li.851@osu.edu [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

  1. Hygiene tests in the anaerobic digestion of household refuse

    Energy Technology Data Exchange (ETDEWEB)

    Maier, H.; Philipp, W.; Wekerle, J.; Strauch, D.

    In a pilot plant the disinfecting effect of composting the effluent of an anaerobic mesophilic digestion process of the organic fraction of household refuse was investigated. The dewatered effluent was mixed with straw as bulking material, put in not aerated windrows and aerobically composted. It was further investigated whether the influent of the digester could be disinfected with lime milk prior to the anaerobic mesophilic digestion process. For the evaluation of the disinfection salmonellas, enterococci, klebsiellas, parvo-, polio- and rotavirus were used as test agents. Temperature, total aerobic germ count, enterobacteriaceae and coliforms were also considered. The effect of lime milk in the influent on the digestion process, survival of the test bacteria and gas production was also studied. Both treatments can result in a hygienically safe product. But composting under the conditions given should not be operated during the winter period. Lime treatment of the influent results in a disinfection of the effluent which immediately can be utilized as liquid sludge in agriculture. (orig.)

  2. 不同有机负荷下混合蔬菜废物厌氧消化性能分析%Anaerobic digestion performance analysis of mixed vegetable wastes under gradient organic loading rate

    Institute of Scientific and Technical Information of China (English)

    元毛毛; 刘研萍; 陈雪; 李秀金; 袁海荣; 邹德勋

    2016-01-01

    Vegetable wastes are generated in large amount in the processes of harvesting, transportation, storage, market and process. It was estimated that about 130 million tons vegetable wastes were produced annually in China, but less than 20%of those were properly treated. Several grievous environmental issues such as foul smell, polluted water, contaminations to soil, and threats to food safety and human health are therefore brought about now and then. Anaerobic digestion represents an environmentally-friend and cost competitive technology which achieves waste treatment and recovery of renewable energy biogas simultaneously. Furthermore, the nutrient abundant digestive juice is a highly valuable bio-fertilizer for agriculture. As is well known, organic loading rate (OLR) is one of the most influential parameters of anaerobic digestion as well as one of the key design parameters of full-scale anaerobic digestion plants. The characteristics of easy biodegradation, high moisture and organic matter content accelerate the anaerobic digestion of vegetable wastes, and OLR therefore plays a vital role to ensure the stable and efficient operation of the anaerobic reactor. The objective of this study was to examine the effect of the OLR on the performance of vegetable wastes anaerobic digestion and to provide detailed information for anaerobic digestion process design. In order to evaluate the digestion performance and figure out the dynamic of the substrate conversion, the experiment was carried out with the continuous stirred-tank reactors at 35℃for 170 days. The hydraulic retention time (HRT) was 20 days while the OLR was set at 1.0, 1.5, 1.75, 2.0, 2.25, 2.5, 3.0, 3.25 and 3.5 g/(L·d) respectively during the whole study. The criteria such as biogas daily yield, methane content, volatile solid (VS) removal percentage were used for assessing the anaerobic digestion performance, while the pH value, alkalinity, oxidation reduction potential (ORP) and volatile fatty acids (VFAs

  3. A methane production feasibility model for central anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.L. (Western Ontario University, London, Canada); Peters, N. (Fundacao de Tecnologia Industrial, Botafogo, Brazil)

    1981-01-01

    A mathematical model was developed for prediction of the practicability of building and operating large centrally located anaerobic digesters for producing methane gas from animal manure. The assumptions were that the manure would be collected from the feedlots and that the product gas would be supplied to an existing pipeline. The model takes account of the farm locations and calculates transportation costs for various numbers of digesters. Digester sizes for each distribution and installation and operating costs are computed. Revenue was then determined on the basis of methane production and fertilizer value recovery. The utility of the model is shown through a study of farms in southwestern Ontario where many small feedlots exist. The results of the study indicate a gas production cost of roughly $0.18/cu m.

  4. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.

    1982-08-01

    The semimicroscopic blue-green alga Spirulina maxima makes an ideal substrate for anaerobic digestion because it is easy to harvest, it can use carbon dioxide from the atmosphere as its carbon source, and its fermentability is higher than that of other small algae. Digestion experiments demonstrated that S. maxima can serve as the sole nutrient for biogas production and that municipal sewage sludge, when adapted to this new substrate, is very stable. During semicontinuous daily-fed trials under non-optimal conditions at an 0.06 lb volatile solids (VS)/ft/sup 3/ (0.97 kg VS/m/sup 3/) loading rate, 33-day retention time, and 86/sup 0/F (30/sup 0/C) digestion temperature, the daily methane yield was 4.2 CF/lb (0.26 m/sup 3//kg) VS added, which represents 47% of the maximum theoretical yield. Studies on optimizing the process are underway.

  5. Anaerobic digestion of giant reed for methane production.

    Science.gov (United States)

    Yang, Liangcheng; Li, Yebo

    2014-11-01

    As a fast growing plant, giant reed has good potential to be used as a feedstock for methane production via anaerobic digestion (AD). The effect of total solids (TS) content, an AD operating parameter, was studied. Results showed that increasing TS from 8% to 38% decreased methane yield, due to the inhibition of volatile fatty acids (VFAs) and total ammonia nitrogen (TAN); while the maximum volumetric methane production was obtained at 20-23% TS. Comparison of solid-state AD (SS-AD) at 20% TS and liquid AD (L-AD) at 8% TS was conducted at feedstock to effluent (F/E) ratios of 2.0, 3.5, and 5.0. The best performance was achieved at an F/E of 2.0, with methane yields of 129.7 and 150.8L-CH4/kg-VS for SS-AD and L-AD, respectively. Overall organic components were degraded by 17.7-28.5% and 24.0-26.6% in SS-AD and L-AD, respectively; among which cellulose showed the highest degradation rate and the highest contribution to methane production.

  6. 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.

  7. Digesters and demographics: identifying support for anaerobic digesters on dairy farms.

    Science.gov (United States)

    Sanders, D J; Roberts, M C; Ernst, S C; Thraen, C S

    2010-11-01

    The dairy industry in the United States is amidst a long-running trend toward fewer, larger dairy farms. This development has created a backlash in some communities over concerns such as odor, waste management, and environmental degradation. Separately, anaerobic digestion has advanced as a waste management technology that potentially offers solutions to some of these issues, providing odor control and a combustible biogas among other things. These digesters require significant capital investments. Voluntary consumer premiums for the renewable energy produced have been used in some instances as a means to move adoption of such systems toward financial feasibility. This project employed a survey to measure Ohio consumers' willingness to pay a premium for renewable energy produced by anaerobic digesters on dairy farms. Cluster analysis was used to segment consumers by willingness to pay, age, education, income, self-identified political inclination, and a composite variable that served as a proxy for respondents' environmental stewardship. Four distinctive groups emerged from the data. Older, less educated respondents were found to have the least amount of support for digesters on dairy farms, whereas politically liberal, environmentally proactive respondents demonstrated the strongest support. Well-educated, affluent respondents and young respondents fell between these 2 groups. Most large dairy farms are generally met with fairly negative responses from their local communities; in contrast, this research finds some popular support for anaerobic digestion technology. Going forward, establishing a positive link between support for anaerobic digesters and for their use on large dairies could open up a new route for less-contested large dairy farm developments. Evaluation of community demographics could become an important part of finding an optimal location for a large dairy farm.

  8. Biogas recovery from microwave heated sludge by anaerobic digestion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy resource.However,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those resources.An effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas production.This article focuses on the effects of microwave heating on sludge anaerobic digestion.Volatile suspended solid(VSS) and chemical organic demand solubilization of heated sludge were investigated.Microwave heating was found to be a rapid and efficient process for releasing organic substrates from sludge.The increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave heating.The effect of the VSS solubilization was primarily dependent on heating temperature.The highest value of VSS dissolving ratio,36.4%,was obtained at 170°C for 30 min.The COD dissolving ratio was about 25% at 170°C.Total organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 150°C and 170°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas production.The total biogas from microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days of digestion.Biogas production was 11.1% to 25.9% higher for excess sludge than for untreated sludge.The VS removal ratios of mixture sludge and excess sludge were 12% and 11% higher,respectively,compared to the untreated sludge.

  9. Viability and fate of Cryptosporidium parvum and Giardia lamblia in tubular anaerobic digesters.

    Science.gov (United States)

    Kinyua, Maureen N; Trimmer, John; Izurieta, Ricardo; Cunningham, Jeffrey; Ergas, Sarina J

    2016-06-01

    In many developing countries where pathogenic diseases of animal waste origin, such as giardiasis and cryptosporidiosis, are often prevalent, facilities are limited to treat livestock waste. However, household-scale anaerobic digesters are currently being promoted for bioenergy production from livestock manure. Since the effluent is often used as a fertilizer for food crops, it is critical to understand the effect of environmental conditions within household-scale digesters on the viability of Cryptosporidium parvum oocysts and Giardia lamblia cysts. In this study, key environmental parameters affecting (oo)cyst inactivation were measured in four tubular anaerobic digesters, which are a type of household-scale digester promoted for treatment of swine waste in rural Costa Rica. Interviews and participant observations were used to understand digester operation and maintenance procedures. Ambient temperatures (21-24°C), near-neutral pH, total ammonia nitrogen (TAN) concentrationsGiardia lamblia and Cryptosporidium parvum were 0.155 ± 0.041 and 0.054 ± 0.006 day(-1), respectively. Temperature and volatile fatty acids were the main factors contributing to Cryptosporidium parvum and Giardia lamblia inactivation. A mathematical model was developed that predicts the concentration of (oo)cysts in the liquid effluent of tubular digesters like those observed in Costa Rica. A mathematical model was developed that predicts the concentration of (oo)cysts in the liquid effluent of tubular digesters like those observed in Costa Rica. Two dimensionless groups can be used to predict the performance of the digesters for inactivating pathogens; both dimensionless groups depend upon the average HRT in the digester. This is the first study to combine mathematical modeling with qualitative analysis, field and laboratory studies to predict the concentrations of (oo)cysts in tubular digester effluents.

  10. [Anaerobic co-digestion of corn stalk and vermicompost].

    Science.gov (United States)

    Chen, Guang-yin; Zheng, Zheng; Zou, Xing-xing; Fang, Cai-xia; Luo, Yan

    2010-02-01

    The characteristics of corn stalk digested alone at different total solid (TS) loading rates and co-digestion of various proportions of corn stalk and vermicompost were investigated by batch model at 35 degrees C +/- 1 degrees C. The organic loading rates (OLRs) studied were in the range of 1.2%-6.0% TS and increasing proportions of vermicompost from 20% to 80% TS. A maximum methane yield of corn stalk digested alone was 217.60 mL/g obtained at the TS loading rate of 4.8%. However, when the TS loading rate was 6.0%, the anaerobic system was acidified and the lowest pH value was 5.10 obtained on day 4 and the biogas productivity decreased. Furthermore, co-digestion of vermicompost and corn stalk in varying proportions were investigated at constant of 6.0% TS. Co-digestion with vermicompost improved the biodegradability of corn stalk and the methane yield was improved by 4.42%-58.61%, and led to higher pH values, higher volatile fatty acids (VFAs) concentration and lower alkalinity content compared with corn stalk digested alone. The maximum biogas yield and methane yield of 410.30 mL/g and 259. 35 mL/g were obtained for 40% vermicompost and 60% corn stalk respectively. Compared with corn stalk digested alone, co-digested with vermicompost didn' t affect methane content and the fermentation type, but promoted the destruction of crystalline of cellulose and the highest destruction rate was 29.36% for 40% vermicompost and 60% corn stalk. Therefore, adding vermicompost was beneficial for the decomposition and increasing the biotransformation rate of corn stalk.

  11. Anaerobic digestion as a key technology in bio-energy production: Current achievements and challenges

    OpenAIRE

    Dewil, Raf; Appels, Lise

    2014-01-01

    Anaerobic digestion has been applied for many decades for the treatment of organic wastes like manure, wastewater sludge and crop residues. Whereas these streams were considered as a nuisance in the past, nowadays, emphasis lies on resource recovery. These wastes are, indeed, providing an important source of renewable energy. Therefore, there is a renewed interest in anaerobic digestion as a technology for sustainable renewable energy production. Also, anaerobic digestion plays a central role...

  12. Nutrient recovery and improvement of anaerobic digestion process by low grade magnesium oxide application

    OpenAIRE

    Romero Güiza, Maycoll Stiven

    2015-01-01

    Anaerobic digestion is a worldwide technology to treat organic waste streams, primarily due to its capacity to produce methane as renewable energy. However, there is an increasing interest on nutrient recovery (N and P), which from both environmental and economic reasons have been identified as key feature in anaerobic digestion plants. Controlled struvite formation has been attracting increasing attention as a near mature technology to recover nutrients from anaerobic digestion. However, str...

  13. Growth and anaerobic digestion characteristics of microalgae cultivated using various types of sewage.

    Science.gov (United States)

    Hidaka, Taira; Inoue, Kenichiro; Suzuki, Yutaka; Tsumori, Jun

    2014-10-01

    Microalgal cultivation combined with anaerobic digestion at wastewater treatment plants is promising to recover energy. This study investigated the growth and anaerobic digestion characteristics of microalgae cultivated using nutrients in sewage. Microalgae were cultivated using primary effluent, secondary effluent, and dewatering filtrate. Microscopic observation indicated that Chlorella was cultivated using dewatering filtrate of anaerobic digestion without controlling the type of species. Batch anaerobic digestion experiments with digested sludge showed that the methane conversion ratio of the cultivated mixture was approximately 40-65%. Different cultivation time did not affect the microalgal contents. Methane recovery mass was 0.13NL-methane/L-cultivation liquor. The C/N ratio of the cultivated mixture was approximately 3-5, but the apparent ammonia release ratio was smaller than that of sewage sludge during digestion. These results proved the applicability of methane recovery from microalgae cultivated using nutrients included in anaerobically digested sludge.

  14. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

    Directory of Open Access Journals (Sweden)

    Fayyaz Ali Shah

    2014-01-01

    Full Text Available Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.

  15. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

    Science.gov (United States)

    Ali Shah, Fayyaz; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Ahmad Asad, Saeed

    2014-01-01

    Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed. PMID:24701142

  16. Performance of sulfate-dependent anaerobic ammo-nium oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; ZHENG Ping; HE YuHui; JIN RenCun

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied. The results showed that both SO42- and NH4+ were chemically stable under anaerobic conditions. They did not react with each other in the absence of biological catalyst (sludge). The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically. The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42- and NH4+ was difficult, though feasible, due to its low standard Gibbs free energy change. The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential (ORP) may be favourable for the biological reaction.

  17. Anaerobic digestion of nitrophilic algal biomass from the Venice Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Rigoni-Stern, S.; Rismondo, R. (Technital S.p.A., Verona (IT)); Szpyrkowicz, L.; Zilio-Grandi, F. (Venice Univ. (Italy)); Vigato, P.A. (Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi)

    1990-01-01

    The feasibility of producing biogas by anaerobic digestion of a nitrophilic algae biomass obtained from the highly eutrophicated Venice Lagoon has been investigated. Methods for harvesting algal biomass have been examined in detail and different pretreatments used prior to analysis and digestion of the algae described. Results obtained from three pilot plant digesters over a period of 12 months using Ulva rigida and Gracilaria as feed material gave no indication of inhibition of the process by either high salinity or high metals content resulting from pollutants discharged into the lagoon. Sulphides were formed during digestion as a consequence of the high sulphate content of the interstitial water as well as the level of sulphur present in the algae. However, the sulphides did not appear to cause inhibition or result in a reduction in gas yield. A maximum biogas production rate of 0.347 m{sup 3} kg VS{sup -1} day{sup -1} was obtained during digestion at a retention time of 20 days with an organic loading rate of 1 kg VS m{sup -3} day{sup -1}. (author).

  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. Hydrolytic activity of alpha-amylase in anaerobic digested sludge.

    Science.gov (United States)

    Higuchi, Y; Ohashi, A; Imachi, H; Harada, H

    2005-01-01

    Hydrolysis is usually considered to be a rate-limiting step in anaerobic digestion. For improving anaerobic solid waste treatments, it is essential to elucidate the mechanism of hydrolysis. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism of hydrolysis. Alpha-amylase activity of solid starch-degrading bacteria (SDB) was estimated through batch experiments with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Monitoring of newly isolated strains of SDB was done by fluorescence in situ hybridization. Results indicated that cell-bound alpha-amylase is chiefly responsible for the hydrolysis in the digested sludge, providing very useful information that the contact between microbial cells and solids is significantly important. The activity of alpha-amylase of the digested sludge remained quite low when not required, but increased as they recognized appropriate substrates. Several-fold higher activity was obtained for starch or maltose as compared to glucose only.

  20. Thermophilic anaerobic digester with ultrafilter for solids stabilization.

    Science.gov (United States)

    Zitomer, D H; Bachman, T C; Vogel, D S

    2005-01-01

    A thermophilic anaerobic digester with ultrafilter (TADU) for solids separation offers potential advantages of higher VS destruction, biomass retention, and pathogen removal. However, potential disadvantages include ultrafilter fouling, decreasing flux, and high VFA concentrations. In this study, a thermophilic anaerobic digester coupled to a sintered titanium, cross-flow ultrafilter was operated for over five months. Dairy manure was digested (HRT of 23 days). The filtrate VFA concentration was low (220 mg/L as HAc), average VS destruction was 49%, and a low average effluent fecal coliform concentration of 10(2) MPN/100 mL was observed. The low coliform value may be beneficial if dewatered biosolids are used for livestock bedding since low pathogen counts help prevent mastitis. Ultrafilter fluxes of 40-80 L/m2-hr were maintained by cleaning using caustic (3.5% NaOH) followed by water and acid (3% phosphoric acid). Sand from livestock bedding was found to damage the pump and ultrafilter. If TADU were implemented at full scale, then replacing sand bedding with dewatered biosolids should be considered.

  1. Treatment of separated piggery anaerobic digestate liquid using woodchip biofilters.

    Science.gov (United States)

    Carney, K N; Rodgers, M; Lawlor, P G; Zhan, X

    2013-01-01

    The Irish nitrates directive restricts the land area suitable for landspreading of pig manure, so anaerobic digestion warrants consideration. In this study, six identical Lodgepole pine woodchip biofilters were set up to treat the separated liquid fraction of digestate after anaerobic digestion of pig manure. Two hydraulic loading rates were examined: 5 L/m2/d (LLR) and 10 L/m2/d (HLR). Following a start-up period of 70 days, an average of 90% and 71% of NH4(+)-N was removed at LLR and HLR, respectively. LLR resulted in higher total nitrogen removals than HLR (p biofilter effluent. A batch experiment testing the capacity of saturated woodchips in removing total oxidized nitrogen (TON) from the effluent of the woodchip biofilters showed that TON was reduced by 323 mg/L from 663 mg/L in 360 h, indicating that the aerobic woodchip biofilters should incorporate a saturated layer ofwoodchips at the base ofthe biofilters to enhance nitrogen removal.

  2. 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.

  3. Growth media in anaerobic fermentative processes: The underestimated potential of thermophilic fermentation and anaerobic digestion.

    Science.gov (United States)

    Hendriks, A T W M; van Lier, J B; de Kreuk, M K

    2017-09-01

    Fermentation and anaerobic digestion of organic waste and wastewater is broadly studied and applied. Despite widely available results and data for these processes, comparison of the generated results in literature is difficult. Not only due to the used variety of process conditions, but also because of the many different growth media that are used. Composition of growth media can influence biogas production (rates) and lead to process instability during anaerobic digestion. To be able to compare results of the different studies reported, and to ensure nutrient limitation is not influencing observations ascribed to process dynamics and/or reaction kinetics, a standard protocol for creating a defined growth medium for anaerobic digestion and mixed culture fermentation is proposed. This paper explains the role(s) of the different macro- and micronutrients, as well as the choices for a growth medium formulation strategy. In addition, the differences in nutrient requirements between mesophilic and thermophilic systems are discussed as well as the importance of specific trace metals regarding specific conversion routes and the possible supplementary requirement of vitamins. The paper will also give some insight into the bio-availability and toxicity of trace metals. A remarkable finding is that mesophilic and thermophilic enzymes are quite comparable at their optimum temperatures. This has consequences for the trace metal requirements of thermophiles under certain conditions. Under non-limiting conditions, the trace metal requirement of thermophilic systems is about 3 times higher than for mesophilic systems. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Anaerobic digester foaming in full-scale cylindrical digesters--effects of organic loading rate, feed characteristics, and mixing.

    Science.gov (United States)

    Subramanian, Bhargavi; Pagilla, Krishna R

    2014-05-01

    Cylindrical anaerobic digesters (AD) were investigated to determine the causes and contributors of AD foaming due to the following: organic loading rate (OLR) and mixing effects, waste activated sludge (WAS) storage effects and foam suppression mixing at the surface of AD, and the effects of primary sludge (PS) solids fraction in the feed sludge. No foaming was observed over the duration of the study, indicating absence of a primary foaming cause even though the suspected contributors to AD foaming were present. Total solids and temperature profiles showed that reducing mixing frequency did not significantly impact digester performance or the homogeneity of the digester contents. The results showed that high organic loading rates, reduced mixing, and feed sludge storage by themselves do not cause foaming in most ADs when the primary foaming cause is absent. Reduced mixing and surface sludge sprays are practical strategies to control AD foaming.

  5. 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

    phosphorus from the anaerobic supernatant of OFMSW is an interesting research topic that has not yet been explored. At the moment, standardization in the design of facilities that treat anaerobic supernatant produced from the treatment of OFMSW is still under development. To move toward this direction, it is first necessary to assess the performance of alternative treatment options. It study concentrates existing data regarding the characteristics of the anaerobic supernatant produced from the treatment of OFMSW and from their co-digestion with other BOW. This provides data documenting the effect of the anaerobic digestion operating conditions on the supernatant quality and critically evaluates alternative options for the post-treatment of the liquid fraction produced from the anaerobic digestion process.

  6. Temperature regulates deterministic processes and the succession of microbial interactions in anaerobic digestion process.

    Science.gov (United States)

    Lin, Qiang; De Vrieze, Jo; Li, Chaonan; Li, Jiaying; Li, Jiabao; Yao, Minjie; Hedenec, Petr; Li, Huan; Li, Tongtong; Rui, Junpeng; Frouz, Jan; Li, Xiangzhen

    2017-10-15

    Temperature plays crucial roles in microbial interactions that affect the stability and performance of anaerobic digestion. In this study, the microbial interactions and their succession in the anaerobic digestion process were investigated at three levels, represented by (1) present and (2) active micro-organisms, and (3) gene expressions under a temperature gradient from 25 to 55 °C. Network topological features indicated a global variation in microbial interactions at different temperatures. The variations of microbial interactions in terms of network modularity and deterministic processes based on topological features, corresponded well with the variations of methane productions, but not with temperatures. A common successional pattern of microbial interactions was observed at different temperatures, which showed that both deterministic processes and network modularity increased over time during the digestion process. It was concluded that the increase in temperature-mediated network modularity and deterministic processes on shaping the microbial interactions improved the stability and efficiency of anaerobic digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Biotechnological application of sustainable biogas production through dry anaerobic digestion of Napier grass.

    Science.gov (United States)

    Dussadee, Natthawud; Ramaraj, Rameshprabu; Cheunbarn, Tapana

    2017-05-01

    Napier grass (Pennisetum purpureum), represents an interesting substrate for biogas production. The research project evaluated biogas potential production from dry anaerobic digestion of Napier grass using batch experiment. To enhance the biogas production from ensiled Napier grass, thermal and alkaline pre-treatments were performed in batch mode. Alkali hydrolysis of Napier grass was performed prior to batch dry anaerobic digestion at three different mild concentrations of sodium hydroxide (NaOH). The study results confirmed that NaOH pretreated sample produced high yield of biogas than untreated (raw) and hot water pretreated samples. Napier grass was used as the mono-substrate. The biogas composition of carbon dioxide (30.10%), methane (63.50%) and 5 ppm of H2S was estimated from the biogas. Therefore, fast-growing, high-yielding and organic matter-enriched of Napier grass was promising energy crop for biogas production.

  8. Stability Analysis of Some Nonlinear Anaerobic Digestion Models

    Directory of Open Access Journals (Sweden)

    Ivan Simeonov

    2010-04-01

    Full Text Available Abstract: The paper deals with local asymptotic stability analysis of some mass balance dynamic models (based on one and on two-stage reaction schemes of the anaerobic digestion (AD in CSTR. The equilibrium states for models based on one (with Monod, Contois and Haldane shapes for the specific growth rate and on two-stage (only with Monod shapes for both the specific growth rate of acidogenic and methanogenic bacterial populations reaction schemes have been determined solving sets of nonlinear algebraic equations using Maples. Their stability has been analyzed systematically, which provides insight and guidance for AD bioreactors design, operation and control.

  9. Biomass stabilization in the anaerobic digestion of wastewater sludges

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C. [Universidad de Sevilla (Spain). Escuela Universitaria Politecnica. Departamento de Ingenieria Quimica y Ambiental; Gutierrez, J.C. [Universidad Pablo de Olavide, Sevilla (Spain). Departamento de Ciencias Ambientales; Lebrato, J. [Universidad de Sevilla (Spain). Escuela Universitaria Politecnica

    2006-07-15

    Sludge stabilization processes include both volatile solid destruction and biomass stabilization. Traditionally, both processes have been considered together, in such a way that, when volatile solid destruction is achieved, the biomass is considered stabilized. In this study, volatile solids reduction and biomass stabilization in the anaerobic digestion of primary, secondary and mixed sludges from municipal wastewater treatment plants were researched in batch cultures by measurements of suspended solids and suspended lipid-phosphate. The estimated kinetic constants were higher in all sludge types tested for the biomass stabilization process, indicating that volatile solids destruction and biomass stabilization are not parallel processes, since the latter one is reached before the former. (author)

  10. Deploying anaerobic digesters: Current status and future possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Lusk, P. [International Energy Agency, Paris (France); Wheeler, P. [ETSU (United Kingdom); Rivard, C. [National Renewable Energy Lab., Golden, CO (United States)

    1996-01-01

    Unmanaged pollutants from putrescible farm, industrial, and municipal wastes degrade in the environment, and methane emitted from their decomposition may contribute to global climate change. Under modern environmental regulations, these wastes are becoming difficult to dispose of using traditional means. One waste management system, anaerobic digestion or AD, not only provides pollution prevention but can also convert a disposal problem into a new profit center. This report is drawn from a special session of the Second Biomass Conference of the Americas. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  11. 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.

  12. The future of anaerobic digestion and biogas utilisation

    DEFF Research Database (Denmark)

    Holm-Nielsen, Jens Bo; Al Seadi, Teodorita; Oleskowicz-Popiel, Piotr

    2009-01-01

    , representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export...... and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel - the biogas. The EU policies concerning renewable...

  13. Biomass stabilization in the anaerobic digestion of wastewater sludges

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C. [Universidad de Sevilla, Dept. de Ingenieria Quimica y Ambiental, Sevilla (Spain); Gutierrez, J.C. [Universidad Pablo de Olavide, Dept. de Ciencias Ambientales, Sevilla (Spain); Lebrato, J. [Universidad de Sevilla, Grupo Tratamiento de Aguas Residuales, Sevilla (Spain)

    2005-07-01

    Sludge stabilization processes include both volatile solid destruction and biomass stabilization. Traditionally, both processes have been considered together, in such a way that, when volatile solid destruction is achieved, the biomass is considered stabilized. In this study, volatile solids reduction and biomass stabilization in the anaerobic digestion of primary, secondary and mixed sludges from municipal wastewater treatment plants were researched in batch cultures by measurements of suspended solids and suspended lipid-phosphate. The estimated kinetic constants were higher in all sludge types tested for the biomass stabilization process, indicating that volatile solids destruction and biomass stabilization are not parallel processes, since the latter one is reached before the former. (Author)

  14. The future of anaerobic digestion and biogas utilisation

    DEFF Research Database (Denmark)

    Holm-Nielsen, Jens Bo; Al Seadi, Teodorita; Oleskowicz-Popiel, Piotr

    2009-01-01

    and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel - the biogas. The EU policies concerning renewable...... energy systems (RES) have set forward a fixed goal of supplying 20% of the European energy demands from RES by year 2020. A major part of the renewable energy will originate from European farming and forestry. At least 25% of all bioenergy in the future can originate from biogas, produced from wet...

  15. THE EFFECT OF SLURRY RECIRCULATION ON ANAEROBIC DIGESTION PERFORMANCE OF KITCHEN WASTE%发酵液回流对餐厨垃圾厌氧消化的影响

    Institute of Scientific and Technical Information of China (English)

    王馨仪; 郭建斌; 吴树彪; 王飞; 董仁杰; 陈理; 庞昌乐

    2012-01-01

    针对厌氧发酵液回流可提高厌氧系统性能,而不适的回流比例又会造成系统酸化的现象,采用单相连续反应器研究了发酵液回流及不同回流比对餐厨垃圾厌氧消化过程的影响。结果表明:在1 gVS/L的有机负荷下进行三种比例(10%、30%、50%)的发酵液回流使系统日平均产气量比不回流阶段分别提高0.7%、13.0%、4.9%,且对气体甲烷含量无显著影响。回流使VFA降解更充分,也使系统缓冲能力得到调节,但在较高的回流比(50%)下会造成Na+积累从而抑制系统产气性能。%For slurry recirculation can improve the performance of anaerobic digestion system while inadaptable recirculation rate may lead to acidification,an anaerobic digestion experiment was carried out on kitchen waste to analyze the effect of slurry recirculation.Results showed that the average daily biogas production was increased by 0.7%,13.0% and 4.9% than its non-recirculation period when the recirculation rate was 10%,30% and 50%,respectively.Slurry recirculation had no harm to the methane percentage.With an increased recirculation rate,system's buffer capacity reduction performed better,but high recirculation rate(50%) would lead to sodium ion accumulation.

  16. Composting of solids separated from anaerobically digested animal manure

    DEFF Research Database (Denmark)

    Chowdhury, Md Albarune; de Neergaard, Andreas; Jensen, Lars Stoumann

    2014-01-01

    We investigated the effects of bulking agents (BA) and mixing ratios on greenhouse gas (GHG) and NH3 emissions from composting digested solids (DS), separated from anaerobically digested manure and other bio-wastes, in small-scale laboratory composters. BA evaluated were plastic tube pieces (PT......), woodchips (WC), bio-char (BC), barley straw (BS) and lupin residues (LR) and were included at a DS:BA of 3:1 or 6:1, resulting in nine treatments: CTDS (control, DS only), PT3:1, PT6:1, WC3:1, WC6:1, BC3:1, BC6:1, BS3:1 and LR3:1. Depending on treatment, C losses via CO2 and CH4 emissions accounted for 41...

  17. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.

    2013-01-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and more recently as a greenhouse gas (GHG) mitigation measure. In this context, AD systems operating at thermophilic temperatures (55-60°C)-compared to mesophilic temperatures (35-40°C)-have the unique feature of producing hygienic soil conditioners with greater process efficiency, higher energy yield, and more GHG savings. Startup of AD systems is often constrained by the lack of acclimated seeds, leading to process instability and failure. The authors focus on strategies to startup thermophilic digesters treating OFMSW in the absence of acclimated seeds and examines constraints associated with process stability and ways to overcome them. Relevant gaps in the literature and future research needs are delineated. © 2013 Taylor & Francis Group, LLC.

  18. 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.

  19. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Jin, Xiangdan; Angelidaki, Irini

    2015-01-01

    Due to increasing environmental concerns of using fossil fuels and decreasing in their reserves, the promotion of renewable energy technologies is crucial. Anaerobic digestion (AD), a well-developed technology converting organic waste into biogas, is gaining increased attention in recent years....... Bioelectrochemical systems (e.g. MFC, MDC, MEC et al.) which transfer chemical energy to electricity by degrading organic waste have attracted great interest due to their environmental friendly and sustainability. In this study, to control and optimize AD process, a smart bioelectrochemical system (microbial...... desalination cell, MDC) was built to realize the on-line measuring the concentration of volatile fatty acid (VFA). The correlation between current densities of the biosensor and VFA concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities...

  20. 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.

  1. Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Heiske, Stefan

    2011-01-01

    for Chaetomorpha linum and 340 ml g VS1 for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5–2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could...... be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during ‘green tides’ in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab...

  2. Anaerobic co-digestion of Tunisian green macroalgae Ulva rigida with sugar industry wastewater for biogas and methane production enhancement.

    Science.gov (United States)

    Karray, Raida; Karray, Fatma; Loukil, Slim; Mhiri, Najla; Sayadi, Sami

    2017-03-01

    Ulva rigida is a green macroalgae, abundantly available in the Mediterranean which offers a promising source for the production of valuable biomaterials, including methane. In this study, anaerobic digestion assays in a batch mode was performed to investigate the effects of various inocula as a mixture of fresh algae, bacteria, fungi and sediment collected from the coast of Sfax, on biogas production from Ulva rigida. The results revealed that the best inoculum to produce biogas and feed an anaerobic reactor is obtained through mixing decomposed macroalgae with anaerobic sludge and water, yielding into 408mL of biogas. The process was then investigated in a sequencing batch reactor (SBR) which led to an overall biogas production of 375mL with 40% of methane. Further co-digestion studies were performed in an anaerobic up-flow bioreactor using sugar wastewater as a co-substrate. A high biogas production yield of 114mL g(-1) VSadded was obtained with 75% of methane. The co-digestion proposed in this work allowed the recovery of natural methane, providing a promising alternative to conventional anaerobic microbial fermentation using Tunisian green macroalgae. Finally, in order to identify the microbial diversity present in the reactor during anaerobic digestion of Ulva rigida, the prokaryotic diversity was investigated in this bioreactor by the denaturing gradient gel electrophoresis (DGGE) method targeting the 16S rRNA gene. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 有机废物厌氧消化热电联产系统性能评价%The performance evaluation on organic waste anaerobic digester for cogeneration systems

    Institute of Scientific and Technical Information of China (English)

    杨善让; 刘志超; 蒋静江; 赵波; 丁宇鸣; 庞俊华

    2013-01-01

    现有农村单体、常温发酵沼气池的产气率较低.环境温度越低,供暖量的需求越大,单体沼气池很难满足农牧地区供暖热负荷的需求.文章研究设计了一套适用于我国北方农牧地区的增强型甲烷供暖、氢气发电的热电联供系统.采用国际能源署颁布的发电成本计算法(LEC)和生命周期分析法(LCA)分别计算评价了有机废物厌氧消化热电联产技术方案和生物质直燃发电技术及生物质气化发电技术的经济和排放性能,并给出了该技术方案的投资回收周期.%The rate of production of biogas of existing rural anaerobic digester was low, which was hard to satisfy the demand of heating load of fanning and stockbreeding areas. And the lower the ambient temperature was, the more the demands of heating were. So it is necessary to find a reasonable solution to solve problems of the energy supply of the distributive residents.A suitable enhanced methane heating system and hydrogen power generation system was designed for rural areas of northern China. The evaluation on the performance of organic waste anaerobic digester for co-generation systems,direct combustion and gasification technology of biomass through LCA algorithms and LEC power generation cost calculation method promulgated by the IEA (International Energy Agency),was attained, and the payback period of the proposed program was also calculated.

  4. Temperature regulates methane production through the function centralization of microbial community in anaerobic digestion.

    Science.gov (United States)

    Lin, Qiang; De Vrieze, Jo; He, Guihua; Li, Xiangzhen; Li, Jiabao

    2016-09-01

    Temperature is crucial for the performance of anaerobic digestion process. In this study of anaerobic digestion of swine manure, the relationship between the microbial gene expression and methane production at different temperatures (25-55°C) was revealed through metatranscriptomic analysis. Daily methane production and total biogas production increased with temperature up to 50°C, but decreased at 55°C. The functional gene expression showed great variation at different temperatures. The function centralization (opposite to alpha-diversity), assessed by the least proportions of functional pathways contributing for at least 50% of total reads positively correlated to methane production. Temperature regulated methane production probably through reducing the diversity of functional pathways, but enhancing central functional pathways, so that most of cellular activities and resource were invested in methanogenesis and related pathways, enhancing the efficiency of conversion of substrates to methane. This research demonstrated the importance of function centralization for efficient system functioning.

  5. 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.

  6. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: Comparison of start-up, reactor stability and process performance

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh, Rangaraj [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Torrijos, Michel, E-mail: michel.torrijos@supagro.inra.fr [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Sousbie, Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lugardon, Aurelien [Naskeo Environnment, 52 rue Paul Vaillant Couturier, F-92240 Malakoff (France); Steyer, Jean Philippe; Delgenes, Jean Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2014-05-01

    Highlights: • Single-phase and two-phase systems were compared for fruit and vegetable waste digestion. • Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS and 83% VS removal. • Substrate solubilization was high in acidification conditions at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2. • Energy yield was lower by 33% for two-phase system compared to the single-phase system. • Simple and straight-forward operation favored single phase process over two-phase process. - Abstract: Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatile solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kg VS/m{sup 3} d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kg VS/m{sup 3} d and then achieved stable performance at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2, with very high substrate solubilization rate and a methane yield of 0.30 m{sup 3} CH{sub 4}/kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of

  7. Report on the design and operation of a full-scale anaerobic dairy manure digester. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Coppinger, E.; Brautigam, J.; Lenart, J.; Baylon, D.

    1979-12-01

    A full-scale anaerobic digester on the Monroe State Dairy Farm was operated and monitored for 24 months with funding provided by the United States Department of Energy, Fuels from Biomass Systems Branch. During the period of operation, operating parameters were varied and the impact of those changes is described. Operational experiences and system component performance are discussed. Internal digester mixing equipment was found to be unnecessary, and data supporting this conclusion are given. An influent/effluent heat exchanger was installed and tested, and results of the tests are included. Recommendations for digester design and operation are presented. Biological stability was monitored, and test results are given. Gas production rates and system net energy are analyzed. The economics of anaerobic digestion are evaluated based on various financing options, design scales, and expected benefits. Under many circumstances digesters are feasible today, and a means of analysis is given.

  8. Industrial symbiosis: corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion.

    Science.gov (United States)

    Wood, Brandon M; Jader, Lindsey R; Schendel, Frederick J; Hahn, Nicholas J; Valentas, Kenneth J; McNamara, Patrick J; Novak, Paige M; Heilmann, Steven M

    2013-10-01

    The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage.

  9. Overcoming challenges to struvite recovery from anaerobically digested dairy manure.

    Science.gov (United States)

    Huchzermeier, Matthew P; Tao, Wendong

    2012-01-01

    Recovering struvite from dairy manure has consistently posed problems for researchers. This study separated solids from anaerobically digested dairy manure using a filtration system. Filtrate was rich in free magnesium (160 to 423 mg/L), ammonium (320 to 1800 mg N/L) and orthophosphate (93 to 332 mg P/L). High concentrations of free calcium (128 to 361 mg/L) and alkalinity (3309 to 6567 mg/L as CaCO3), however, may hinder struvite precipitation. Batch precipitation tests were conducted to identify and overcome factors that interfere with struvite formation. Precipitation tests at pH 9 identified calcium and ionic strength as most probable interferences. Calcium addition did not significantly change phosphorus removal efficiency, but decreased struvite purity because of formation of calcium phosphates when Ca:P activity ratio was greater than 0.5 to 1. Batch tests demonstrated effective calcium removal from anaerobically digested dairy manure through precipitation of calcium carbonate at pH 9 to 10 while retaining magnesium and orthophosphate, lessening hindrance to struvite formation.

  10. State estimation for anaerobic digesters using the ADM1.

    Science.gov (United States)

    Gaida, D; Wolf, C; Meyer, C; Stuhlsatz, A; Lippel, J; Bäck, T; Bongards, M; McLoone, S

    2012-01-01

    The optimization of full-scale biogas plant operation is of great importance to make biomass a competitive source of renewable energy. The implementation of innovative control and optimization algorithms, such as Nonlinear Model Predictive Control, requires an online estimation of operating states of biogas plants. This state estimation allows for optimal control and operating decisions according to the actual state of a plant. In this paper such a state estimator is developed using a calibrated simulation model of a full-scale biogas plant, which is based on the Anaerobic Digestion Model No.1. The use of advanced pattern recognition methods shows that model states can be predicted from basic online measurements such as biogas production, CH4 and CO2 content in the biogas, pH value and substrate feed volume of known substrates. The machine learning methods used are trained and evaluated using synthetic data created with the biogas plant model simulating over a wide range of possible plant operating regions. Results show that the operating state vector of the modelled anaerobic digestion process can be predicted with an overall accuracy of about 90%. This facilitates the application of state-based optimization and control algorithms on full-scale biogas plants and therefore fosters the production of eco-friendly energy from biomass.

  11. Repeated pulse feeding induces functional stability in anaerobic digestion.

    Science.gov (United States)

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

    2013-07-01

    Anaerobic digestion is an environmental key technology in the future bio-based economy. To achieve functional stability, a minimal microbial community diversity is required. This microbial community should also have a certain 'elasticity', i.e. the ability to rapidly adapt to suboptimal conditions or stress. In this study it was evaluated whether a higher degree of functional stability could be achieved by changing the feeding pattern, which can change the evenness, dynamics and richness of the bacterial community. The first reactor (CSTR stable ) was fed on daily basis, whereas the second reactor (CSTR dynamic ) was fed every 2 days. Average biogas production was 0.30 l CH4 l(-1) day(-1) in both reactors, although daily variation was up to four times higher in the CSTR dynamic compared with the CSTR stable during the first 50 days. Bacterial analysis revealed that this CSTR dynamic had a two times higher degree of bacterial community dynamics. The CSTR dynamic also appeared to be more tolerant to an organic shock load of 8 g COD l(-1) and ammonium levels up to 8000 mg TAN l(-1). These results suggest that the regular application of a limited pulse of organic material and/or a variation in the substrate composition might promote higher functional stability in anaerobic digestion.

  12. 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.

  13. [Municipal biowaste thermal-hydrolysis and ASBR anaerobic digestion].

    Science.gov (United States)

    Hou, Hua-hua; Wang, Wei; Hu, Song; Xu, Yi-xian

    2010-02-01

    Thermal-hydrolysis can remarkably improve the solid organics dissolving efficiency of urban biomass waste, and anaerobic sequencing batch reactor (ASBR) was used to improve the efficiency of urban biomass waste anaerobic digestion. The optimum thermal-hydrolysis temperature and holding time was 175 degrees C and 60 min, the volatile suspended solid (VSS) dissolving ratio of kitchen waste, fruit-and-vegetable waste and sludge were 31.3%, 31.9% and 49.7%, respectively. Two ASBR and one continuous-flow stirred tank reactor (CSTR) were started at hydraulic retention time (HRT) = 20 d, COD organic loading rate (OLR) = 3.2-3.6 kg/(m3 x d). The biogas production volumes were 5656 mL/d(A1), 6335 mL/d(A2) and 3 103 mL/d(CSTR), respectively; VSS degradation ratios were 45.3% (A1), 50.87% (A2), 20.81% (CSTR), and the total COD (TCOD) removal rates were 88.1% (A1), 90% (A2), 72.6% (CSTR). In ASBR, organic solid and anaerobic microorganism were remained in the reactor during settling period. When HRT was 20 d, the solid retention time (SRT) was over 130 d, which made ASBR higher efficiency than CSTR.

  14. 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

  15. 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

  16. Dynamic real-time substrate feed optimization of anaerobic co-digestion plants

    NARCIS (Netherlands)

    Gaida, Daniel

    2014-01-01

    In anaerobic co-digestion plants a mix of organic materials is converted to biogas using the anaerobic digestion process. These organic materials, called substrates, can be crops, sludge, manure, organic wastes and many more. They are fed on a daily basis and significantly affect the biogas producti

  17. Dynamic real-time substrate feed optimization of anaerobic co-digestion plants

    NARCIS (Netherlands)

    Gaida, Daniel

    2014-01-01

    In anaerobic co-digestion plants a mix of organic materials is converted to biogas using the anaerobic digestion process. These organic materials, called substrates, can be crops, sludge, manure, organic wastes and many more. They are fed on a daily basis and significantly affect the biogas producti

  18. Effects of anaerobic digestion and aerobic treatment on gaseous emissions from dairy manure storages

    Science.gov (United States)

    Effects of anaerobic digestion and aerobic treatment on the reduction of gaseous emissions from dairy manure storages were evaluated in this study. Screened dairy manure containing 3.5% volatile solids (VS) was either anaerobically digested or aerobically treated prior to storage in air-tight vessel...

  19. Whole farm impact of anaerobic digestion and biogas use on a New York dairy farm

    Science.gov (United States)

    Anaerobic digestion of manure for biogas production is one of many options for reducing the carbon footprint of milk production. This process reduces greenhouse gas emissions but increases the potential nitrogen and phosphorus losses from the farm. An anaerobic digester component was added to the In...

  20. Evaluation of biogas production by dry anaerobic digestion of switchgrass-animal manure mixtures

    Science.gov (United States)

    Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application without adverse environmental effects. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion (> 15% TS; total solid) has an advantage ov...

  1. Speciation modeling of ammonia and other major solutes in anaerobic digesters

    Science.gov (United States)

    Anaerobic digestion of high-nitrogen wastes can be inhibited by high concentrations of un-ionized ammonia, NH**3 (aq). Understanding the toxicity of NH**3 (aq) to anaerobic digestion requires an understanding of the mechanisms controlling its concentration. Previous work on ammonia toxicity in an...

  2. 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-

  3. Dynamic real-time substrate feed optimization of anaerobic co-digestion plants

    NARCIS (Netherlands)

    Gaida, Daniel

    2014-01-01

    In anaerobic co-digestion plants a mix of organic materials is converted to biogas using the anaerobic digestion process. These organic materials, called substrates, can be crops, sludge, manure, organic wastes and many more. They are fed on a daily basis and significantly affect the biogas

  4. An anaerobic digestion apparatus and its performance analysis%一种厌氧发酵简易装置及其沼气发酵效果分析

    Institute of Scientific and Technical Information of China (English)

    冷国辉; 张帅松; 陈绍江

    2012-01-01

    试验设计了一种能够对多个样品同时进行厌氧发酵的简易装置,为评估试验装置性能,以ND608、ND627、ND691、先玉335、高油5580和大刍草的秸秆为原料进行批量厌氧发酵试验。结果表明:1)本试验装置容易获得厌氧环境,37℃恒温条件下,厌氧反应的启动较快,装样10h后,有明显的气泡产生。反应40d后,厌氧发酵反应终止。2)CH4体积分数为64.09%~65.55%,CO2体积分数为28.80%~31.60%;其中大刍草(291.05mL/g)和高油5580(281.67mL/g)的CH4单位产气量较高。由此可见:本试验设计的发酵装置能够满足目前厌氧发酵反应的要求,符合对多个玉米秸秆样品同时评估的要求。%An experimental apparatus for anaerobic digestion was designed for simultaneous evaluation of multiple samples.In order to evaluate the performance of the apparatus,the maize stalk samples of ND608,ND627,ND691,XY335,high oil hybrid ND5580 and Teosinte were employed for biogas production.The results indicated that anaerobic atomsphere in the apparatus can be maintained.At 37 ℃,anaerobic digestion started after 10 h of sample loading and bubbles generated which could be considered as initiate biogas production.The reaction time could continuously last for about 40 days.The volumetric content of produced methane was ranged from 64.09% to 65.55% among six samples.The average content of CO2 was ranged from 28.80% to 31.60%.The methane yields of Teosinte and high oil hybrid ND5580 were higher than normal maize(ND608,ND627,ND691,XY335).The newly designed apparatus could be used for the evaluation of biogas production performance for large number of samples.

  5. 玉米秸与鸡粪混合厌氧消化产气性能与协同作用%Performance and synergistic effect of anaerobic co-digestion of corn stover and chicken manure

    Institute of Scientific and Technical Information of China (English)

    冯亚君; 袁海荣; 张良; 李超; 高健; 李秀金

    2013-01-01

    Performance and synergistic effect of anaerobic co-digestion of corn stover and chicken manure were investigated. Nine ratios of corn stover to chicken manure ( CS/CM) (1:0,1: 1,1:2,1:3,1:4,2: 1,3: 1, 4:l,and 0: 1)) and three loading rates of total solids (TS) (50, 65 and 80 g/L) were used. The results showed that compared to co-digestion of untreated corn stover and chicken manure, 5. 5% ~ 62% more biogas productions were obtained for co-digestion of NaOH pretreated ones. The co-digestion with CS/CM of 1: 2 and loading rate of 50 g TS/L obtained the highest total methane production of 19 488 mL, which was 32. 6% and 11.4% higher than that of the CS/CM ratios of 1:0 and 0: 1 at the same loading rate. The synergistic effect of co-digestion of chicken manure with NaOH pretreated corn stover contributed to methane yield increase of 7. 1% ~ 17. 7% . The synergistic effect of the co-digestion with CS/CM of 1: 2 was 25% ~ 150% higher than other radios. This study would provide the parameters for effective operation and optimal design of anaerobic co-digestion facility of straw and manure.%研究了玉米秸与鸡粪在不同混合比例条件下的厌氧消化产气性能和协同作用效果.设计了9种玉米秸与鸡粪的混合比例(1∶0、1∶1、1∶2、1∶3、1∶4、2∶1、3∶1、4∶1、0:1),每种比例分别在3个不同负荷(50、65和80 g/L)下进行混合厌氧消化.结果表明,与未预处理玉米秸与鸡粪混合厌氧消化相比,NaOH预处理玉米秸与鸡粪混合厌氧消化的单位TS产气量提高了5.5% ~ 62%.当预处理玉米秸与鸡粪的混合比例为1∶2、上料负荷为50 g/L时消化产气性能最好,此时的累积甲烷产量达到19 488 mL,比相同负荷下单一玉米秸厌氧消化的累积甲烷产量高出32.6%,比单一鸡粪厌氧消化的累积甲烷产量高出11.4%.混合厌氧消化协同作用的贡献率达到7.1% ~17.7%,其中玉米秸与鸡粪的比例为1∶2时,其贡献率

  6. 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.

  7. Evaluation of Novel Inoculation Strategies for Solid State Anaerobic Digestion of Yam Peelings in Low-Tech Digesters

    DEFF Research Database (Denmark)

    Heiske, Stefan; Jurgutis, Linas; Kádár, Zsófia

    2015-01-01

    The operation of household scale anaerobic digesters is typically based on diluted animal dung, requiring stabled livestock and adequate water availability. This excludes many rural households in low-income countries from the benefits of a domestic biogas digester. Solid state anaerobic digestion...... inoculation strategies and evaluating the necessity of dung addition as a supportive biomass. In initial lab scale trials 143 +/- 4 mL CH4/g VS (volatile solids) were obtained from a mixture of yam peelings and dung digested in a multi-layer-inoculated batch reactor. In a consecutive incubation cycle in which...

  8. Anaerobic digestion of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse in UASB reactor.

    Science.gov (United States)

    Ribeiro, Fernanda Resende; Passos, Fabiana; Gurgel, Leandro Vinícius Alves; Baêta, Bruno Eduardo Lobo; de Aquino, Sérgio Francisco

    2017-04-15

    In the context of a sugarcane biorefinery, sugarcane bagasse produced may be pretreated generating a solid and liquid fraction. The solid fraction may be used for 2G bioethanol production, while the liquid fraction may be used to produce biogas through anaerobic digestion. The aim of this study consisted in evaluating the anaerobic digestion performance of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse. For this, hydrothermal pretreatment was assessed in a continuous upflow anaerobic sludge blanket (UASB) reactor operated at a hydraulic retention time (HRT) of 18.4h. Process performance was investigated by varying the dilution of sugarcane bagasse hydrolysate with a solution containing xylose and the inlet organic loading rate (OLR). Experimental data showed that an increase in the proportion of hydrolysate in the feed resulted in better process performance for steps using 50% and 100% of real substrate. The best performance condition was achieved when increasing the organic loading rate (OLR) from 1.2 to 2.4gCOD/L·d, with an organic matter removal of 85.7%. During this period, the methane yield estimated by the COD removal would be 270LCH4/kg COD. Nonetheless, when further increasing the OLR to 4.8gCOD/L·d, the COD removal decreased to 74%, together with an increase in effluent concentrations of VFA (0.80gCOD/L) and furans (115.3mg/L), which might have inhibited the process performance. On the whole, the results showed that anaerobic digestion of sugarcane bagasse hydrolysate was feasible and may improve the net energy generation in a bioethanol plant, while enabling utilization of the surplus sugarcane bagasse in a sustainable manner. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: comparison of start-up, reactor stability and process performance.

    Science.gov (United States)

    Ganesh, Rangaraj; Torrijos, Michel; Sousbie, Philippe; Lugardon, Aurelien; Steyer, Jean Philippe; Delgenes, Jean Philippe

    2014-05-01

    Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatile solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kgVS/m3 d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m3 CH4/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kgVS/m3 d and then achieved stable performance at 7.0 kgVS/m3 d and pH 5.5-6.2, with very high substrate solubilization rate and a methane yield of 0.30 m3 CH4/kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of energy during hydrolysis in the TPAR and the deficit in methane production in the TPMR attributed to COD loss due to biomass synthesis and adsorption of hard COD onto the flocs. These results including the complicated operational procedure of the two-phase process and the economic factors suggested that the single-phase process could be the preferred system for FVW.

  10. Anaerobic Digestion Scale Levels and Their Energy Yields. A comparison of energy yields of different manure-and co-digestion scale levels

    NARCIS (Netherlands)

    Konneman, Bram

    2007-01-01

    Anaerobic digestion is a biological process whereby, in the absence of oxygen, organic matter is converted into biogas and digestate. In recent years anaerobic digestion has received re-newed attention in the Dutch agricultural sector. Co-digestion, in wh

  11. Anaerobic Digestion Scale Levels and Their Energy Yields. A comparison of energy yields of different manure-and co-digestion scale levels

    NARCIS (Netherlands)

    Konneman, Bram

    2007-01-01

    Anaerobic digestion is a biological process whereby, in the absence of oxygen, organic matter is converted into biogas and digestate. In recent years anaerobic digestion has received re-newed attention in the Dutch agricultural sector. Co-digestion, in wh

  12. 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.

  13. 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.

  14. Anaerobic co-digestion of aquatic flora and quinoa with manures from Bolivian Altiplano.

    Science.gov (United States)

    Alvarez, René; Lidén, Gunnar

    2008-01-01

    Quinoa stalk (Chenopodium quinoa Willd.) from agricultural crop residue, totora (Schoenoplectus tatora) and o-macrophytes (aquatic flora) from Lake Titicaca (on the Bolivian Altiplano) were studied in a wet anaerobic co-digestion process together with manure from llama, cow and sheep. Anaerobic semi-continuous experiments were performed in (10) 2-l reactors at a temperature of 25 degrees C with 30 days of hydraulic retention time (HRT) and an organic loading rate (OLR) of 1.8 kg VS m(-3) d(-1). Totora was found to be the best co-substrate. In mixture ratios of 1:1 (VS basis), it increased the biogas productivity by 130% for llama manure, 60% for cow manure, and 40% for sheep manure. It was possible to use up to 58% (VS basis) of totora in the substrate. Higher concentrations (including pure totora) could not be digested, as that caused acidification problems similar to those caused by other lignocellulosic materials. When quinoa and o-macrophytes were used as co-substrates, the increase in biogas productivity was slightly less. However, these co-substrates did not cause any operational problems. An additional advantage of quinoa and o-macrophytes was that they could be used in any proportion (even in pure form) without causing any destabilization problems in the anaerobic digestion process.

  15. Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

    Science.gov (United States)

    Song, Yong-Hui; Qiu, Guang-Lei; Yuan, Peng; Cui, Xiao-Yu; Peng, Jian-Feng; Zeng, Ping; Duan, Liang; Xiang, Lian-Cheng; Qian, Feng

    2011-06-15

    Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

  16. [Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography].

    Science.gov (United States)

    Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2012-04-01

    The analysis of seven aliphatic carboxylic acids (formic, acetic, propionic, iso-butyric, n-butyric, iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid, perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection. The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column (TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column (TSKgel Super IC-A/C). Good separation was performed on the TSKgel SCX in shorter retention times. For the TSKgel Super IC-A/C, peak shape of the acids was sharp and symmetrical in spite of longer retention times. In addition, the mutual separation of the acids was good except for iso- and n-butyric acids. The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series), lower concentrations of PFBA and sulfuric acid as eluents, non-suppressed conductivity detection and UV detection at 210 nm. This analysis was applied to anaerobic digestion process waters. The chromatograms with conductivity detection were relatively simpler compared with those of UV detection. The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  17. Performance of sulfate-dependent anaerobic ammonium oxidation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The performance of sulfate-dependent anaerobic ammonium oxidation was studied.The results showed that both SO42-and NH4+ were chemically stable under anaerobic conditions.They did not react with each other in the absence of biological catalyst(sludge).The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing ammonium with sulfate anaero-bically.The average reduction of sulfate and ammonium was 71.67 mg.L-1 and 56.82 mg.L-1 at high concentrations.The reaction between SO42-and NH4+ was difficult,though feasible,due to its low standard Gibbs free energy change.The experiment demonstrated that high substrate concentrations and low oxidation-reduction potential(ORP) may be favourable for the biological reaction.

  18. Anaerobic digestion in the treatment of waste and wastewater effluent; Digestion anaerobia en el tratamiento de efluentes y lodos residuales

    Energy Technology Data Exchange (ETDEWEB)

    Baraza, X.; Galimary, F.; Torres, R.

    2003-07-01

    Anaerobic digestion is one of the processes most commonly employed at the present time in treating effluent and wastewater containing a large proportion of organic matter. This article describes the process involved and its applications in the environmental engineering field. It also discusses the physical, chemical and biological factors influencing anaerobic digestion and which therefore have a bearing on whether to implements this process and how it is actually applied from a technological point of view. (Author) 125 refs.

  19. ADM1 simulation of High-solid anaerobic digestion with feasibility study for El Gabal El Asfar WWTP.

    Science.gov (United States)

    2017-09-25

    Performance of continuous mesophilic high-solid anaerobic digestion (HSAD) was simulated using Anaerobic Digestion Model No 1 (ADM1), under different conditions (solid concentrations, sludge retention time [SRT], organic loading rate [OLR] and type of sludge), ADM1 implementation using the proposed biochemical parameters proved to be useful tool for the prediction and control of HSAD as the model predicted the behavior of the tested sets of data with a considerable accuracy especially for SRT more than 13 days. The model then used to investigate the possibility of changing the existing conventional anaerobic digestion (CAD) units in Gabal El Asfar WWTP into HSAD instead of establishment of new (CAD) units and results show that the system will be feasible, HSAD will produce the same bioenergy combined with a decrease in capital, operational and maintenance cost.

  20. Developing a nutrient recovery process for recovering nutrients in anaerobic digestate in low income countries

    OpenAIRE

    Rose, Christopher

    2015-01-01

    It is estimated that 2.7 billion people worldwide are served by on-site sanitation facilities that require faecal sludge management. Anaerobic digestion is a treatment mechanism that can provide faecal sludge management, methane production and an effluent digestate rich in nutrients. However, there is a paucity of information regarding the composition of the input faecal sludge which hinders the advancement of anaerobic digestion treatment and downstream nutrient recovery to...

  1. Study of the Process of Hydraulic Mixing in Anaerobic Digester of Biogas Plant

    Directory of Open Access Journals (Sweden)

    Karaeva Julia V.

    2015-03-01

    Full Text Available Two systems of hydraulic mixing in a vertical cylindrical anaerobic digester: standard and modernised are discussed in the paper. Numerical investigations that were carried out are focused on a study of hydrodynamic processes in an aerobic digester using two various systems of hydraulic mixing as well as on analysis of the efficiency of methane fermentation process accomplished under different geometric parameters of an anaerobic digester and systems of hydraulic mixing.

  2. Low temperature anaerobic digestion of mixtures of llama, cow and sheep manure for improved methane production

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Rene [IIDEPROQ, UMSA, Plaza del Obelisco 1175, La Paz (Bolivia)]|[Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund (Sweden); Liden, Gunnar [Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund (Sweden)

    2009-03-15

    Biogas production in anaerobic digestion in farm-scale units is typically performed under mesophilic conditions when used for producing domestic fuel and stabilizing animal waste for the use of digested manure as a fertilizer. Previous studies on the digestion of llama and cow manure have shown the feasibility of producing biogas under altiplano conditions (low pressure and low temperature) and of llama manure as a promising feedstock. The present study concerns the utilization of various mixtures of feedstocks from the Bolivian altiplano under low temperature conditions (18-25 C). Laboratory scale experiments were performed on the digestion of mixtures of llama, sheep and cow manure in a semi-continuous process using ten 2-L stainless steel digesters to determine the effects of organic loading rate (OLR) and the feed composition. The semi-continuous operation of mixture of llama-cow-sheep manure proved to be a reliable system, which could be operated with good stability. The results suggest that in a system digesting a mixture of llama-cow-sheep manure at low temperature (18-25 C) the maximum OLR value is between 4 and 6 kg VS m{sup 3} d{sup -1}. The methane yields obtained in the mixture experiments were in the range 0.07-0.14 m{sup 3} kg{sup -1} VS added, with a methane concentration in the gas of between 47 and 55%. (author)

  3. Study on Anaerobic Digestion Performance of Three Kinds of Perennial Energy Grasses from South China Area%三种能源草厌氧发酵制备生物燃气初步研究

    Institute of Scientific and Technical Information of China (English)

    牛红志; 李连华; 孔晓英; 孙永明; 袁振宏; 周贤友

    2015-01-01

    The three kinds of energy grasses: Pennisetum purpureu, Miscanthus sinensis and Miscanthus floridulus from the Southchina area were conducted for biogas by using batch anaerobic digestion technical process at mesophilic temperature (35 ± 1oC), in this paper. The experiment results showed that the three kinds of energy grasses had different anaerobic fermentation performances:the highest daily biogas production were 31.33, 24.84 and 19.51 Nml·(gVSadded)−1·d−1, the cumulative biogas production were 355.78, 285.58 and 235.38 Nml·(gVSadded)−1, and the cumulative CH4 production were 166.43, 109.89 and 97.20 Nml·(gVSadded)−1, accounted for 33.83%, 21.67% and 19.48% of the theoretical CH4 production, respectively. Biogas yield of Pennisetum purpureu was obviously higher than that of the others, which was mainly because it had higher content of easily biodegradable organics. Modified Gompertz equation could be used well to fit the anaerobic digestion process of energy grass producing biogas. The simulation results were that the cumulative biogas production of the three kinds of grasses were 344.81, 290.11 and 279.01 Nml·(gVSadded)−1, and the delay times of anaerobic digestion tests were 5.96, 0.71 and 0 d.%以华南地区生长的多年生草本植物象草、芒草和五节芒为原料,采用序批式中温(35±1℃)厌氧发酵工艺,研究这三种能源草制备生物燃气的性能。结果表明:象草、芒草和五节芒的最高日产气率分别为31.33、24.84和19.51 Nml·(gVSadded)−1·d−1,原料产气率分别为355.78、285.58和235.38 Nml·(gVSadded)−1,产甲烷率分别为166.43、109.89和97.20 Nml·(gVSadded)−1,占理论产甲烷率的33.83%、21.67%和19.48%,象草的厌氧发酵性能优于芒草和五节芒的主要原因是象草中纤维素、半纤维素等易降解的有机物含量较高。修正的Gompertz方程拟合效果较好,象草、芒草和五节芒的累积产气量分别为344.81、290.11

  4. 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.

  5. Mesophilic anaerobic co-digestion of aloe peel waste with dairy manure in the batch digester: Focusing on mixing ratios and digestate stability.

    Science.gov (United States)

    Huang, Xinlei; Yun, Sining; Zhu, Jiang; Du, Tingting; Zhang, Chen; Li, Xue

    2016-10-01

    Anaerobic co-digestion of aloe peel waste (APW) with dairy manure (DM) was evaluated in terms of biogas and methane yield, volatile solids (VS) removal rate, and the stability of digestate. Batch experiments were performed under mesophilic condition (36±1°C) at five different APW/DM wet weight ratios (1:0, 3:1, 1:1, 1:3, and 0:1). Experimental methane yield from the mixtures was higher than the yield from APW or DM alone, indicating the synergistic effect and benefits of co-digestion of APW with DM. The optimal mixing ratio of APW/DM was found to be 3:1. The cumulative methane yield was 195.1mL/g VS and the VS removal rate was 59.91%. The characteristics of the digestate were investigated by the thermal analysis which indicated the high stability in the samples of the co-digestion. The co-digestion can be an efficient way to improve the degradation efficiency of the bio-wastes and increase the energy output.

  6. 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.

  7. Intermediate-Scale High-Solids Anaerobic Digestion System Operational Development

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C. J.

    1995-02-01

    Anaerobic bioconversion of solid organic wastes represents a disposal option in which two useful products may be produced, including a medium Btu fuel gas (biogas) and a compost-quality organic residue. The application of high-solids technology may offer several advantages over conventional low-solids digester technology. The National Renewable Energy Laboratory (NREL) has developed a unique digester system capable of uniformly mixing high-solids materials at low cost. During the first 1.5 years of operation, a variety of modifications and improvements were instituted to increase the safety, reliability, and performance of the system. Those improvements, which may be critical in further scale-up efforts using ,the NREL high-solids digester design are detailed in this report.

  8. 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.

  9. COMPARISON OF TWO CHEMICAL PRETREATMENTS OF RICE STRAW FOR BIOGAS PRODUCTION BY ANAEROBIC DIGESTION

    Directory of Open Access Journals (Sweden)

    Zilin Song,

    2012-06-01

    Full Text Available Lignocellulosic biomass is considered the most abundant renewable resource that has the potential to contribute remarkably in the supply of biofuel. Previous studies have shown that chemical pretreatment prior to anaerobic digestion (AD can increase the digestibility of lignocellulosic biomass and methane yield. In the present study, the effect of rice straw pretreatment using ammonium hydroxide (NH3•H2O and hydrogen peroxide (H2O2 on the biogasification performance through AD was investigated. A self-designed, laboratory-scale, and continuous anaerobic biogas digester was used for the evaluation. Results showed that the contents of the rice straw, i.e. the lignin, cellulose, and hemicellulose were degraded significantly after the NH3•H2O and H2O2 treatments, and that biogas production from all pretreated rice straw increased. In addition, the optimal treatments for biogas production were the 4% and 3% H2O2 treatments (w/w, which yielded 327.5 and 319.7 mL/gVS, biogas, respectively, higher than the untreated sample. Biogas production from H2O2 pretreated rice straw was more favorable than rice straw pretreated with same concentration of ammonia, ranking in the order of 4% ≈ 3% > 2% > 1%. The optimal amount of H2O2 treatment for rice straw biogas digestion is 3% when economics and biogas yields are considered.

  10. Effect of temperature and pH on the anaerobic digestion of grass silage

    OpenAIRE

    2014-01-01

    The operating temperature and pH level in the digester during anaerobic digestion and the retention period are among the major factors that affect the rate of biogas production. Therefore, this paper evaluates the effects of temperature and pH in anaerobic digestion of grass silage. Grass silage was digested in 1000ml at different temperatures (35 ○C, 40 ○C, 45 ○C and 50 ○C) and pH (6.5, 6.8 &7.2). The digesters were shaken everyday to prevent the formation of surface crust which may prevent ...

  11. 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)

  12. The future of anaerobic digestion and biogas utilization

    DEFF Research Database (Denmark)

    Holm-Nielsen, J.B.; Al Seadi, T.; Oleskowicz-Popiel, Piotr

    2009-01-01

    , representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export......One of the common tendencies of animal production activities in Europe and in developed countries in general is to intensify the animal production and to increase the size of the animal production units. High livestock density is always accompanied by production of a surplus of animal manure...... and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel – the biogas. The EU policies concerning renewable...

  13. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure

    Science.gov (United States)

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion, yet in temperate climate digesters, require a considerable amount of additional heat en...

  14. Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake.

    Science.gov (United States)

    Hamid, Hanna; Eskicioglu, Cigdem

    2013-09-15

    Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively.

  15. 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.

  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. Coupling hydrothermal liquefaction and anaerobic digestion for energy valorization from model biomass feedstocks.

    Science.gov (United States)

    Posmanik, Roy; Labatut, Rodrigo A; Kim, Andrew H; Usack, Joseph G; Tester, Jefferson W; Angenent, Largus T

    2017-06-01

    Hydrothermal liquefaction converts food waste into oil and a carbon-rich hydrothermal aqueous phase. The hydrothermal aqueous phase may be converted to biomethane via anaerobic digestion. Here, the feasibility of coupling hydrothermal liquefaction and anaerobic digestion for the conversion of food waste into energy products was examined. A mixture of polysaccharides, proteins, and lipids, representing food waste, underwent hydrothermal processing at temperatures ranging from 200 to 350°C. The anaerobic biodegradability of the hydrothermal aqueous phase was examined through conducting biochemical methane potential assays. The results demonstrate that the anaerobic biodegradability of the hydrothermal aqueous phase was lower when the temperature of hydrothermal processing increased. The chemical composition of the hydrothermal aqueous phase affected the anaerobic biodegradability. However, no inhibition of biodegradation was observed for most samples. Combining hydrothermal and anaerobic digestion may, therefore, yield a higher energetic return by converting the feedstock into oil and biomethane. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Anaerobic co-digestion in the Netherlands. A system analysis on greenhouse gas emissions from Dutch co-digesters.

    NARCIS (Netherlands)

    Groenewold, Henk

    2013-01-01

    Summary Anaerobic digestion (AD) is a biological process whereby, in the absence of oxygen, organic matter is transformed into biogas and digestate. In recent years AD has received new attention in the Dutch agricultural sector by introducing the co-dige

  19. Anaerobic co-digestion in the Netherlands. A system analysis on greenhouse gas emissions from Dutch co-digesters.

    NARCIS (Netherlands)

    Groenewold, Henk

    2013-01-01

    Summary Anaerobic digestion (AD) is a biological process whereby, in the absence of oxygen, organic matter is transformed into biogas and digestate. In recent years AD has received new attention in the Dutch agricultural sector by introducing the co-dige

  20. 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.

  1. Evaluation on direct interspecies electron transfer in anaerobic sludge digestion of microbial electrolysis cell.

    Science.gov (United States)

    Zhao, Zisheng; Zhang, Yaobin; Quan, Xie; Zhao, Huimin

    2016-01-01

    Increase of methanogenesis in methane-producing microbial electrolysis cells (MECs) is frequently believed as a result of cathodic reduction of CO2. Recent studies indicated that this electromethanogenesis only accounted for a little part of methane production during anaerobic sludge digestion. Instead, direct interspecies electron transfer (DIET) possibly plays an important role in methane production. In this study, anaerobic digestion of sludge were investigated in a single-chamber MEC reactor, a carbon-felt supplemented reactor and a common anaerobic reactor to evaluate the effects of DIET on the sludge digestion. The results showed that adding carbon felt into the reactor increased 12.9% of methane production and 17.2% of sludge reduction. Imposing a voltage on the carbon felt further improved the digestion. Current calculation showed that the cathodic reduction only contributed to 27.5% of increased methane production. Microbial analysis indicated that DIET played an important role in the anaerobic sludge digestion in the MEC.

  2. Effects of Oxytetracycline on Methane Production and the Microbial Communities During Anaerobic Digestion of Cow Manure

    Institute of Scientific and Technical Information of China (English)

    KE Xin; WANG Chun-yong; LI Run-dong; ZHANG Yun

    2014-01-01

    The effects of different concentrations of oxytetracycline (OTC) on the dynamics of bacterial and archaeal communities during the mesophilic anaerobic digestion (37°C) of cow manure were investigated. Before anaerobic digestion, OTC was added to digesters at concentrations of 20, 50, and 80 mg L-1, respectively. Compared with no-antibiotic control, all methane productions underwent different levels of inhibition at different concentrations of OTC. Changes in the bacterial and archaeal communities were discussed by using PCR-denaturing gradient gel electrophoresis (DGGE). Results showed that OTC affected the richness and diversity of bacterial and archaeal communities. The bacterial genus Flavobacterium and an uncultured bacterium (JN256083.1) were detected throughout the entire process of anaerobic digestion and seemed to be the functional bacteria. Methanobrevibacter boviskoreani and an uncultured archaeon (FJ230982.1) dominated the archaeal communities during anaerobic digestion. These microorganisms may have high resistance to OTC and may play vital roles in methane production.

  3. Microbial community dynamics of a continuous mesophilic anaerobic biogas digester fed with sugar beet silage

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, B.; Neumann, L.; Scherer, P. [Hochschule fuer Angewandte Wissenschaften, Fakultaet Life Sciences, Lifetec Process Engineering, Hamburg (Germany)

    2008-08-15

    The aim of the study was to investigate the long-term fermentation of an extremely sour substrate without any addition of manure. In the future, the limitation of manure and therefore the anaerobic digestion of silage with a very low buffering capacity will be an increasing general bottleneck for energy production from renewable biomass. During the mesophilic anaerobic digestion of sugar beet silage (without top and leaves) as the sole substrate (without any addition of manure), which had an extreme low pH of around 3.3, the highest specific gas production rate (spec. GPR) of 0.72 L/g volatile solids (VS) d was achieved at a hydraulic retention time (HRT) of 25 days compared to an organic loading rate (OLR) of 3.97 g VS/L d at a pH of around 6.80. The methane (CH{sub 4}) content of the digester ranged between 58 and 67 %, with an average of 63 %. The use of a new charge of substrate (a new harvest of the same substrate) with higher phosphate content improved the performance of the biogas digester significantly. The change of the substrate charge also seemed to affect the methanogenic population dynamics positively, thus improving the reactor performance. Using a new substrate charge, a further decrease in the HRT from 25 to 15 days did not influence the digester performance and did not seem to affect the structure of the methanogenic population significantly. However, a decrease in the HRT affected the size of the methanogenic population adversely. The lower spec. GPR of 0.54 L/g VS d attained on day 15 of the HRT could be attributed to a lower size of methanogenic population present in the anaerobic digester during this stage of the process. Furthermore, since sugar beet silage is a relatively poor substrate, in terms of the buffering capacity and the availability of nutrients, an external supply of buffering agents and nutrients is a prerequisite for a safe and stable digester operation. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  4. Anaerobic digestion of pig farm sewage; Digestion Anaerobia de aguas residuales de granjas porcicolas

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Mendez Novelo, R.; Magana Pietra, A. [Universidad Autonoma de Yucatan. Departamento de Ingenieria Ambiental, Yucatan, Mexico (Mexico)

    1997-04-01

    The 534 litre anaerobic digester, composed of a UASB reactor at the bottom and a high-rate sedimentator at the top, was fed with pig and ruminants sewage. The formation of volatile fatty acids (VFA) was monitored as VFA concentration is usually decisive in controlling fermentation during the non-methanogenic stage. The results obtained with different retention times show the presence of different VFA concentrations, the highest concentration corresponding to a retention time of one day. The process was also found to be extremely elastic. (Author) 12 refs.

  5. 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.

  6. 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.

  7. Assessing solid digestate from anaerobic digestion as feedstock for ethanol production.

    Science.gov (United States)

    Teater, Charles; Yue, Zhengbo; MacLellan, James; Liu, Yan; Liao, Wei

    2011-01-01

    Ethanol production using solid digestate (AD fiber) from a completely stirred tank reactor (CSTR) anaerobic digester was assessed comparing to an energy crop of switchgrass, and an agricultural residue of corn stover. A complete random design was fulfilled to optimize the reaction conditions of dilute alkali pretreatment. The most effective dilute alkali pretreatment conditions for raw CSTR AD fiber were 2% sodium hydroxide, 130 °C, and 3 h. Under these pretreatment conditions, the cellulose concentration of the AD fiber was increased from 34% to 48%. Enzymatic hydrolysis of 10% (dry basis) pretreated AD fiber produced 49.8 g/L glucose, while utilizing 62.6% of the raw cellulose in the AD fiber. The ethanol fermentation on the hydrolysate had an 80.3% ethanol yield. The cellulose utilization efficiencies determined that the CSTR AD fiber was a suitable biorefining feedstock compared to switchgrass and corn stover.

  8. Nitrogen and phosphorus recovery from anaerobic co-digestion residues of poultry manure and maize silage via struvite precipitation.

    Science.gov (United States)

    Yilmazel, Y Dilsad; Demirer, Goksel N

    2013-08-01

    Anaerobic digestion is commonly used for the stabilization of agricultural and animal wastes. However, owing to the stringent environmental criteria, anaerobic digester effluents need to be further treated to reduce nutrient loads to the receiving water bodies. Struvite precipitation is one of the promising techniques applied for this purpose. Yet, in the majority of cases, struvite precipitation is only applied to the liquid phase of anaerobic digester effluents. This study investigated the recovery of nutrients from both the liquid and the solid phases of the phase-separated effluent of a full-scale biogas plant co-digesting poultry manure and maize silage. Struvite precipitation in the liquid phase led to 72.1% and 95.1% average removal efficiencies of ammonium-nitrogen (NH4-N) and orthophosphate respectively. Changing the external phosphorus source did not make any statistically significant difference in nutrient removal. An acidic phosphorus-dissolution process was applied to the solid phase sample to obtain a phosphorus-enriched solution. More than 90.0% of both NH4-N and PO4-P were recovered from the phosphorus-enriched solution with the amendments of magnesium and phosphorus. In the experiments performed without any addition of external magnesium- and phosphorus-containing chemicals, almost complete (99.6%) PO4-P recovery and partial (14.6%) NH4-N recovery were obtained. The results of this study could contribute to the understanding of nutrient recovery from anaerobic digestion residues of manure and agricultural wastes by struvite precipitation.

  9. Anaerobic Digestion and Combined Heat and Power Study

    Energy Technology Data Exchange (ETDEWEB)

    Frank J. Hartz

    2011-12-30

    One of the underlying objectives of this study is to recover the untapped energy in wastewater biomass. Some national statistics worth considering include: (1) 5% of the electrical energy demand in the US is used to treat municipal wastewater; (2) This carbon rich wastewater is an untapped energy resource; (3) Only 10% of wastewater treatment plants (>5mgd) recover energy; (4) Wastewater treatment plants have the potential to produce > 575 MW of energy nationwide; and (5) Wastewater treatment plants have the potential to capture an additional 175 MW of energy from waste Fats, Oils and Grease. The WSSC conducted this study to determine the feasibility of utilizing anaerobic digestion and combined heat and power (AD/CHP) and/or biosolids gasification and drying facilities to produce and utilize renewable digester biogas. Digester gas is considered a renewable energy source and can be used in place of fossil fuels to reduce greenhouse gas emissions. The project focus includes: (1) Converting wastewater Biomass to Electricity; (2) Using innovative technologies to Maximize Energy Recovery; and (3) Enhancing the Environment by reducing nutrient load to waterways (Chesapeake Bay), Sanitary Sewer Overflows (by reducing FOG in sewers) and Greenhouse Gas Emissions. The study consisted of these four tasks: (1) Technology screening and alternative shortlisting, answering the question 'what are the most viable and cost effective technical approaches by which to recover and reuse energy from biosolids while reducing disposal volume?'; (2) Energy recovery and disposal reduction potential verification, answering the question 'how much energy can be recovered from biosolids?'; (3) Economic environmental and community benefit analysis, answering the question 'what are the potential economic, environmental and community benefits/impacts of each approach?'; and (4) Recommend the best plan and develop a concept design.

  10. State-of-the-art of anaerobic digestion technology for industrial wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Rajeshwari, K.V.; Balakrishnan, M.; Kansal, A.; Kusum Lata; Kishore, V.V.N. [Tata Energy Research Institute, New Delhi (India). Darbari Seth Block

    2000-06-01

    Anaerobic digestion is the most suitable option for the treatment of high strength organic effluents. The presence of biodegradable components in the effluents coupled with the advantages of anaerobic process over other treatment methods makes it an attractive option. This paper reviews the suitability and the status of development of anaerobic reactors for the digestion of selected organic effluents from sugar and distillery, pulp and paper, slaughterhouse and dairy units. In addition, modifications in the existing reactor designs for improving the efficiency of digestion has also been suggested. (author)

  11. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.

    Science.gov (United States)

    Arikan, Osman A; Mulbry, Walter; Lansing, Stephanie

    2015-09-01

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters.

  12. 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).

  13. 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.

  14. Carbon dynamics and retention in soil after anaerobic digestion of dairy cattle feed and faeces

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Olesen, Jørgen E; Møller, Henrik Bjarne

    2013-01-01

    Animal manure and plant biomass are increasingly used for methane production. While minerals may be conserved during gas generation, the composition of the biogenic material is changed and less carbon (C) is returned to the soil in the digested residue. We evaluated the fate of C in ruminant feed....... When C lost during the pre-treatments was included, the long-term C retention in soil accounted for 12–14% of the C initially present in the feed. We conclude that soil microbial activity is reduced when residues are anaerobically digested for biogas before being applied to soil. However, the retention...... treated differently before added to soil: no treatment (feed), anaerobic digestion (digested feed), consumed by cattle (faeces), consumed by cattle and anaerobic digestion (digested faeces). The materials were incubated for 245 days at 20 °C. The net CO2 release was determined and fitted to a kinetic C...

  15. 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.

  16. 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)

  17. ANAEROBIC DIGESTION OF ANIMAL WASTE: EFFECT OF MODE OF MIXING

    Science.gov (United States)

    Laboratory-scale digesters were operated to study the effect of mixing (via biogas recirculation, impeller mixing, and slurry recirculation) on biogas production. Three sets of experiments were performed using cow manure slurry feed with either 50, 100, or 150 g/L total solids (TS) concentrations (r...

  18. 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.

  19. 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.

  20. Kinetics and dynamic modelling of batch anaerobic digestion of municipal solid waste in a stirred reactor.

    Science.gov (United States)

    Nopharatana, Annop; Pullammanappallil, Pratap C; Clarke, William P

    2007-01-01

    A series of batch, slurry anaerobic digestion experiments were performed where the soluble and insoluble fractions, and unwashed MSW were separately digested in a 200l stirred stainless steel vessel at a pH of 7.2 and a temperature of 38 degrees C. It was found that 7% of the total MSW COD was readily soluble, of which 80% was converted to biogas; 50% of the insoluble fraction was solubilised, of this only 80% was converted to biogas. The rate of digesting the insoluble fraction was about four times slower than the rate of digesting the soluble fraction; 48% of the total COD was converted to biogas and 40% of the total nitrogen was converted to ammonia. Soluble and insoluble fractions were broken down simultaneously. The minimum time to convert 95% of the degradable fraction to biogas was 20 days. The lag phase for the degradation of insoluble fraction of MSW can be overcome by acclimatising the culture with the soluble fraction. The rate of digestion and the methane yield was not affected by particle size (within the range of 2-50mm). A dynamic model was developed to describe batch digestion of MSW. The parameters of the model were estimated using data from the separate digestion of soluble and insoluble fractions and validated against data from the digestion of unwashed MSW. Trends in the specific aceticlastic and formate-utilising methanogenic activity were used to estimate initial methanogenic biomass concentration and bacterial death rate coefficient. The kinetics of hydrolysis of insoluble fraction could be adequately described by a Contois equation and the kinetics of acidogenesis, and aceticlastic and hydrogen utilising methanogenesis by Monod equations.

  1. Comparison of solid-state anaerobic digestion and composting of yard trimmings with effluent from liquid anaerobic digestion.

    Science.gov (United States)

    Lin, Long; Yang, Liangcheng; Xu, Fuqing; Michel, Frederick C; Li, Yebo

    2014-10-01

    Solid-state anaerobic digestion (SS-AD) and composting of yard trimmings with effluent from liquid AD were compared under thermophilic condition. Total solids (TS) contents of 22%, 25%, and 30% were studied for SS-AD, and 35%, 45%, and 55% for composting. Feedstock/effluent (F/E) ratios of 2, 3, 4, 5, and 6 were tested. In composting, the greatest carbon loss was obtained at 35% TS, which was 2-3 times of that at 55% TS and was up to 50% higher than that in SS-AD. In SS-AD, over half of the degraded carbon was converted to methane with the greatest methane yield of 121 L/kg VS(feedstock). Methane production from SS-AD was low at F/E ratios of 2 and 3, likely due to the inhibitory effect of high concentrations of ammonia nitrogen (up to 5.6g/kg). The N-P-K values were similar for SS-AD digestate and compost with different dominant nitrogen forms.

  2. The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

    Directory of Open Access Journals (Sweden)

    Tatiana Prado

    2013-02-01

    Full Text Available The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV, rotavirus species A (RVA, norovirus genogroup II (NoV GII and the hepatitis A virus (HAV from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%, RVA, NoV GII (45% and HAV (18%, indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management.

  3. The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

    Science.gov (United States)

    Prado, Tatiana; Guilayn, Wilma de Carvalho Pereira Bonet; Gaspar, Ana Maria Coimbra; Miagostovich, Marize Pereira

    2013-01-01

    The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods) used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV), rotavirus species A (RVA), norovirus genogroup II (NoV GII) and the hepatitis A virus (HAV) from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR) was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%), RVA, NoV GII (45%) and HAV (18%), indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management. PMID:23440119

  4. Energy recovery from wastewater treatment plants through sludge anaerobic digestion: effect of low-organic-content sludge.

    Science.gov (United States)

    Zhang, Yuyao; Li, Huan

    2017-09-18

    During anaerobic digestion, low-organic-content sludge sometimes is used as feedstock, resulting in deteriorated digestion performance. The operational experience of conventional anaerobic digestion cannot be applied to this situation. To investigate the feature of low-organic-content sludge digestion and explain its intrinsic mechanism, batch experiments were conducted using designed feedstock having volatile solids (VS) contents that were 30-64% of total solids (TS). The results showed that the accumulative biogas yield declined proportionally from 173.7 to 64.8 ml/g VS added and organic removal rate decreased from 34.8 to 11.8% with decreasing VS/TS in the substrate. The oligotrophic environment resulting from low-organic-content substrates led to decreased microbial activity and a switch from butyric fermentation to propionic fermentation. A first-order model described the biogas production from the batch experiments very well, and the degradation coefficient decreased from 0.159 to 0.069 day(-1), exhibiting a positive relation with organic content in substrate. The results observed here corroborated with data from published literature on anaerobic digestion of low-organic-content sludge and showed that it may not be feasible to recover energy from sludge with an organic content lower than 50% through mono digestion.

  5. Significance of vivianite precipitation on the mobility of iron in anaerobically digested sludge

    Directory of Open Access Journals (Sweden)

    Jimmy Roussel

    2016-09-01

    Full Text Available Anaerobic digestion requires a balanced availability of micro-nutrients with ideal growth conditions to reach optimal organic degradation and biogas production. Iron is the most abundant of the essential metals in an anaerobic digester and its mobility has a strong impact on microorganisms through its own bioavailability, but also through its influence on the bioavailability of other metals. Most previous research on iron mobility in anaerobic digestion has focused on sulfide as the controlling anion because digesters traditionally are sulfide rich and phosphate poor. However, chemical phosphorus removal (CPR at wastewater treatment works (WWTW can elevate phosphate concentrations in the digester 10-fold or more. The goal of this research was hence to examine the accepted wisdom of iron-sulfide dominance prevailing in all anaerobic digesters and by evaluating the potential for iron phosphate formation in municipal digesters treating CPR sludge. To fulfil this aim, iron compounds were identified experimentally from full-scale digesters at WWTW with CPR and the most likely iron species identified through modelling according to their thermodynamic probability of formation under the specific environmental conditions experienced in each anaerobic digester. Experimental and modelling data were then combined to identify the main chemical reactions controlling iron mobility in those anaerobic digesters.Results show that speciation of iron in the sampled anaerobic digesters was controlled by the solid phase through a primary reaction (sulfide precipitation to form pyrite and ferrous sulfide and secondary reaction (phosphate precipitation to form vivianite. However, iron-sulfide precipitates represented only 10-30% of the total iron in the sampled digesters, while iron-phosphate precipitates represented more than 70%. The significance of the high quantity of vivianite in these digesters is that phosphate-rich anaerobic digesters will be more iron

  6. Growth kinetics and competition between Methanosarcina and Methanosaeta in mesophilic anaerobic digestion.

    Science.gov (United States)

    Conklin, Anne; Stensel, H David; Ferguson, John

    2006-05-01

    Methanosarcina species with a high maximum specific growth rate (mumax) and high half-saturation coefficient (KS) and Methanosaeta species with a low mumax and low KS are the only known aceticlastic methanogens. Because of Methanosaeta's low KS, the low acetate concentrations in conventional, mesophilic anaerobic digestion yield Methanosaeta dominance. However, Methanosarcina absorbs increases in acetate more efficiently and thus promotes more stable digestion. This paper tests the hypothesis that decreasing digester feeding frequencies can increase Methanosarcina predominance. Two acetate-fed reactors were established at a 17-day solids retention time. One reactor was fed hourly, and one was fed once daily. Microscopic and molecular methods were used to verify that the hourly fed reactor enriched for Methanosaeta, while the daily fed reactor enriched for Methanosarcina. Growth and substrate-use kinetics were measured for each reactor. A digester overload condition was simulated, and the Methanosarcina-enriched reactor was found to perform better than the Methanosaeta-enriched reactor. These findings indicate that Methanosarcina dominance can be achieved with infrequent feedings, leading to more stable digestion.

  7. 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).

  8. Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters.

    Science.gov (United States)

    Yap, S D; Astals, S; Jensen, P D; Batstone, D J; Tait, S

    2017-06-01

    Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH4 kgVSfed(-1) for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

    Science.gov (United States)

    Wikandari, Rachma; Sari, Noor Kartika; A'yun, Qurrotul; Millati, Ria; Cahyanto, Muhammad Nur; Niklasson, Claes; Taherzadeh, Mohammad J

    2015-02-01

    Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., γ-hexalactone and γ-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of γ-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of γ-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, γ-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L.

  10. 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.

  11. Analysis of biogas production through anaerobics digestion using cow dung and various co-substrates

    Directory of Open Access Journals (Sweden)

    Dhanapal Thamilselvan

    2016-01-01

    Full Text Available Biodegradable waste is a sustainable energy resource. In coming years biogas technology can be very useful worldwide, since biogas can be obtained from biodegradable waste material. This technology is based on waste reduction and also is helpful in the clean-up process of India. In this experiment, we have made single-phase biogas set-ups by using two-liter bottles. The fermentation time of the anaerobic digestion for the efficient use of gas as a fuel is about sixteen days. In our biogas digester set-ups for waste decomposion anaerobic co-digestion process is utilized. The primary feed stock is cow dung, whereas the grass, fruit, and vegetable waste are used as co-subtracts. The pH value was maintained at the range level of 6.5 to 6.9. The output biogas yield was 1.59 ml, 1.28 ml, 1.03 ml, and 0.95 ml, within an approximate period of sixteen days. Biogas obtained from cow dung and grass waste is almost identical as biogas obtained from the experimental set-up 1 (pure cow dung. Main performance characteristics of biogas formation were presented in this paper. In order to analyze a daily biogas formation, the pH value, temperature, and hydraulic retention time were changed in this experiment.

  12. Effects of different biofilm carriers on biogas production during anaerobic digestion of corn straw.

    Science.gov (United States)

    Liu, Yongdi; Zhu, Yingdong; Jia, Honghua; Yong, Xiaoyu; Zhang, Lijuan; Zhou, Jun; Cao, Zebin; Kruse, Andrea; Wei, Ping

    2017-07-30

    This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F420, and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers. The polypropylene fiber system maintained the highest biogas and methane production in the reactor, which was 44.80% and 49.84% higher than that noted in the control, respectively, during the entire anaerobic fermentation cycle. Meanwhile, the polypropylene fiber system exhibited the highest TS, VS, and COD removal efficiency. The results of high-throughput sequencing indicated that the dominant species in the polypropylene fiber system were Methanoregula and Methanobacterium. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 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...

  14. Anaerobic Digestion Facility List, US and Territories, 2015, US EPA Region 9

    Data.gov (United States)

    U.S. Environmental Protection Agency — This table lists anaerobic digestion (AD) facilities associated with the Food Waste Recipient Count by Zip Code GIS dataset. This table identifies operational AD...

  15. Anaerobic co-digestion of water hyacinth and cow dung for biogas production

    OpenAIRE

    OROKA FRANK OKE; AKHIHIERO THELMA

    2015-01-01

    Co-digestion of water hyacinth and cow dung under anaerobic condition was studied. Results indicate a progressive increase in biogas yield with increased cow dung in the co-ferment mixture of water hyacinth: cow dung

  16. A simplified stoichiometric kinetic model for estimating the concentration of reaction products in anaerobic digestion.

    Science.gov (United States)

    Kim, Moonil; Cui, Fenghao

    2017-10-01

    Modelling the anaerobic digestion process is often complex and needs to consider many input parameters. This study simplified the modelling procedure by developing an idealized stoichiometric kinetic model that simulates the anaerobic digestion process with only a few parameters: composition coefficients (α and β), maximum substrate utilization rate (qmax), endogenous-decay coefficient (b), biodegradable fraction (fd), and temperature coefficient (Ф). We validated the model with the operating results of a pilot two-phase anaerobic digester for food wastewater disposal and calculated using the MATLAB programing software. The comparison between the experimental and model simulation results demonstrated a good agreement. The developed model correctly simulated the fate of chemicals in the anaerobic digestion process.

  17. Advances towards understanding and engineering direct interspecies electron transfer in anaerobic digestion.

    Science.gov (United States)

    Barua, Sajib; Dhar, Bipro Ranjan

    2017-11-01

    Direct interspecies electron transfer (DIET) is a recently discovered microbial syntrophy where cell-to-cell electron transfer occurs between syntrophic microbial species. DIET between bacteria and methanogenic archaea in anaerobic digestion can accelerate the syntrophic conversion of various reduced organic compounds to methane. DIET-based syntrophy can naturally occur in some anaerobic digester via conductive pili, however, can be engineered via the addition of various non-biological conductive materials. In recent years, research into understanding and engineering DIET-based syntrophy has emerged with the aim of improving methanogenesis kinetics in anaerobic digestion. This article presents a state-of-art review focusing on the fundamental mechanisms, key microbial players, the role of electrical conductivity, the effectiveness of various conductive additives, the significance of substrate characteristics and organic loading rates in promoting DIET in anaerobic digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Hybrid neural modelling of an anaerobic digester with respect to biological constraints.

    Science.gov (United States)

    Karama, A; Bernard, O; Gouzé, J L; Benhammou, A; Dochain, D

    2001-01-01

    A hybrid model for an anaerobic digestion process is proposed. The fermentation is assumed to be performed in two steps, acidogenesis and methanogenesis, by two bacterial populations. The model is based on mass balance equations, and the bacterial growth rates are represented by neural networks. In order to guarantee the biological meaning of the hybrid model (positivity of the concentrations, boundedness, saturation or inhibition of the growth rates) outside the training data set, a method that imposes constraints in the neural network is proposed. The method is applied to experimental data from a fixed bed reactor.

  19. Production of energy by anaerobic digestion of water weeds. Energifremstilling ved anaerob udraadning af vandloebsgroede

    Energy Technology Data Exchange (ETDEWEB)

    Willumsen, H.C.

    1989-03-15

    The aim was to discover the potential of water weeds from streams etc. as a source of biomass for conversion by anaerobic digestion to methane fuel. This form of utilization of vegetation in waterways could also have environmental and economical advantages. The conversion process, and the forms of water vegetations, are described in detail. It was shown that where cow manure and a percolate were mixed with the biomass the production of methane was more satisfactory. An experiment was also carried out where limestone was added to the water plants under conversion, this seemed to obstruct the production of methane. The addition of redox was significant, and possibly negative, in relation to the results. It was concluded that this form of biomass derived from water weeds had an advantageous effect on methane production when added to other forms of organic materials. (AB).

  20. 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.

  1. 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.

  2. 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

  3. Anaerobic co-digestion of cork based oil sorbent and cow manure or sludge

    OpenAIRE

    Cavaleiro, A. J.; Neves, T. M.; Guedes, Ana P.; Alves, M.M.; Pinto, P.; Silva, S.P.; Sousa, D.Z.

    2015-01-01

    Cork, a material with great economic, social and environmental importance in Portugal, is also a good oil sorbent that can be used in the remediation of oil spills. The oil-impregnated cork can be easily removed, but requires further treatment. In the case of vegetable oil spills, anaerobic digestion may be a potential solution. This study aims to evaluate the effect of adding cork contaminated with sunflower oil as co-substrate in anaerobic digestion processes. Biodegradability assays were p...

  4. Modelling anaerobic co-digestion in Benchmark Simulation Model No. 2: Parameter estimation, substrate characterisation and plant-wide integration.

    Science.gov (United States)

    Arnell, Magnus; Astals, Sergi; Åmand, Linda; Batstone, Damien J; Jensen, Paul D; Jeppsson, Ulf

    2016-07-01

    Anaerobic co-digestion is an emerging practice at wastewater treatment plants (WWTPs) to improve the energy balance and integrate waste management. Modelling of co-digestion in a plant-wide WWTP model is a powerful tool to assess the impact of co-substrate selection and dose strategy on digester performance and plant-wide effects. A feasible procedure to characterise and fractionate co-substrates COD for the Benchmark Simulation Model No. 2 (BSM2) was developed. This procedure is also applicable for the Anaerobic Digestion Model No. 1 (ADM1). Long chain fatty acid inhibition was included in the ADM1 model to allow for realistic modelling of lipid rich co-substrates. Sensitivity analysis revealed that, apart from the biodegradable fraction of COD, protein and lipid fractions are the most important fractions for methane production and digester stability, with at least two major failure modes identified through principal component analysis (PCA). The model and procedure were tested on bio-methane potential (BMP) tests on three substrates, each rich on carbohydrates, proteins or lipids with good predictive capability in all three cases. This model was then applied to a plant-wide simulation study which confirmed the positive effects of co-digestion on methane production and total operational cost. Simulations also revealed the importance of limiting the protein load to the anaerobic digester to avoid ammonia inhibition in the digester and overloading of the nitrogen removal processes in the water train. In contrast, the digester can treat relatively high loads of lipid rich substrates without prolonged disturbances.

  5. Hygienization of sludge through anaerobic digestion at 35, 55 and 60 °C.

    Science.gov (United States)

    Kjerstadius, H; la Cour Jansen, J; De Vrieze, J; Haghighatafshar, S; Davidsson, A

    2013-01-01

    Legislation in Sweden and the European Union concerning the use of sewage sludge in agriculture is under revision and future concentration limits for pathogens in treated sludge are likely to be expected. The aim of this study was to evaluate the hygienization of Salmonella, Escherichia coli, Enterococcus and Clostridium perfringens through continuous anaerobic digestion at 35, 55 or 60 °C, as well as to investigate process stability and methane production at 60 °C. The results indicated that digestion at 55 or 60 °C with a minimum exposure time of 2 h resulted in good reduction of Salmonella, E. coli and Enterococcus and that anaerobic digestion could thus be used to reach the concentration limits suggested for the EU, as well as Sweden. Furthermore, stable continuous anaerobic digestion of sludge was achieved at 60 °C, albeit with 10% less methane production compared to digestion at 35 and 55 °C.

  6. 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.

  7. Improved Design of Anaerobic Digesters for Household Biogas Production in Indonesia: One Cow, One Digester, and One Hour of Cooking per Day

    Directory of Open Access Journals (Sweden)

    Joseph G. Usack

    2014-01-01

    Full Text Available A government-sponsored initiative in Indonesia to design and implement low-cost anaerobic digestion systems resulted in 21 full-scale systems with the aim to satisfy the cooking fuel demands of rural households owning at least one cow. The full-scale design consisted of a 0.3 m diameter PVC pipe, which was operated as a conventional plug-flow system. The system generated enough methane to power a cooking stove for ∼1 h. However, eventual clogging from solids accumulation inside the bioreactor proved to be a major drawback. Here, we improved the digester configuration to remedy clogging while maintaining system performance. Controlled experiments were performed using four 9-L laboratory-scale digesters operated at a temperature of 27±1°C, a volatile solids loading rate of 2.0 g VS·L−1·day−1, and a 21-day hydraulic retention time. Two of the digesters were replicates of the original design (control digesters, while the other two digesters included internal mixing or effluent recycle (experimental digesters. The performance of each digester was compared based on methane yields, VS removal efficiencies, and steady-state solids concentrations during an operating period of 311 days. Statistical analyses revealed that internal mixing and effluent recycling resulted in reduced solids accumulation compared to the controls without diminishing methane yields or solids removal efficiencies.

  8. Source analysis of organic matter in swine wastewater after anaerobic digestion with EEM-PARAFAC.

    Science.gov (United States)

    Zeng, Zhuo; Zheng, Ping; Ding, Aqiang; Zhang, Meng; Abbas, Ghulam; Li, Wei

    2017-03-01

    Swine wastewater is one of the most serious pollution sources, and it has attracted a great public concern in China. Anaerobic digestion technology is extensively used in swine wastewater treatment. However, the anaerobic digestion effluents are difficult to meet the discharge standard. The results from batch experiments showed that plenty of refractory organic matter remained in the effluents after mesophilic anaerobic digestion for 30 days. The effluent total COD (tCOD) and soluble COD (sCOD) were 483 and 324 mg/L, respectively, with the sCOD/tCOD ratio of 0.671. Fluorescence excitation-emission matrix (EEM) coupled with parallel factor analysis (PARAFAC) revealed that the dissolved organic matter in the effluents was tryptophan-like substance, humic acid substance, and fulvic acid substance. Based on the appearance time during anaerobic digestion, tryptophan-like substance and humic acid substance were inferred to originate from the raw swine wastewater, and the fulvic acid substance was inferred to be formed in the anaerobic digestion. This work has revealed the source of residual organic matter in anaerobic digestion of swine wastewater and has provided some valuable information for the post-treatment.

  9. Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors

    DEFF Research Database (Denmark)

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

    2002-01-01

    Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process...

  10. Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Alatriste-Mondragon, Felipe; Iranpour, R.

    2003-01-01

    Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants. Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge. To date, many studies exist on the anaerobic biodegradation rates of PAE, especially...

  11. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    Science.gov (United States)

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  12. Extension of anaerobic digestion model no. 1 with the processes of sulphate reduction

    NARCIS (Netherlands)

    Fedorovich, V.; Lens, P.N.L.; Kalyuzhnyi, S.

    2003-01-01

    In the present work, the Anaerobic Digestion Model No. 1 (ADM1) for computer simulation of anaerobic processes was extended to the processes of sulfate reduction. The upgrade maintained the structure of ADM1 and included additional blocks describing sulfate-reducing processes (multiple reaction stoi

  13. 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.

  14. 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.

  15. 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

  16. Effects of digestate from anaerobically digested cattle slurry and plant materials on soil microbial community and emission of CO2 and N2O

    DEFF Research Database (Denmark)

    Johansen, Anders; Carter, Mette Sustmann; Jensen, Erik S.

    2013-01-01

    Anaerobic digestion of animal manure and crop residues may be employed to produce biogas as a climate-neutral source of energy and to recycle plant nutrients as fertilizers. However, especially organic farmers are concerned that fertilizing with the digestates may impact the soil microbiota...... and fertility because they contain more mineral nitrogen (N) and less organic carbon (C) than the non-digested input materials (e.g. raw animal slurry or fresh plant residues). Hence, an incubation study was performed where (1) water, (2) raw cattle slurry, (3) anaerobically digested cattle slurry/maize, (4...... of the other treatments during the 9 days. Regarding microbial community composition, grass-clover induced the largest changes in microbial diversity measures compared to the controls, where raw cattle slurry and the two anaerobically digested materials (cattle slurry/maize, cattle slurry/grass-clover) only...

  17. 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 results are crucial to improve the energy balance of the biodiesel production from Tetraselmis suecica, as well as proposing an alternative way to treat the wastes derived from the microalgae biodiesel production.

  18. Community Anaerobic Digester: Powered by Students and Driving Practical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Richmond Hall, Joan [Vermont Sustainable Jobs Fund, Montpelier, VT (United States); O' Leary, Mary [Vermont Sustainable Jobs Fund, Montpelier, VT (United States)

    2016-03-23

    The Vermont Tech Community Anaerobic Digester (VTCAD) was conceived and funded by a partnership of educational, agricultural, waste management and environmental groups to create a living laboratory demonstrating the value of recycling nutrients, renewable energy and agricultural co-products from organic wastes. VTCAD was constructed on the Randolph Center, Vermont campus of Vermont Tech, a public college offering engineering technology, agricultural, renewable energy education and workforce training. With funding from the U.S. Department of Energy (DOE), the Vermont State Colleges and others, construction was completed in early 2014 and the facility has been operational since April 2014. At full power, VTCAD uses 16,000 gallons of manure and organic residuals to produce 8,880 kilowatt hours (kWh) of electricity per day, ‘waste’ heat that will be used to heat four campus buildings, bedding material for the college dairy herds and recycled nutrients used as crop fertilizer. VTCAD uses a mixture of manure from co-managed farms and organic residuals collected from the community. Feedstock materials include brewery residuals, the glycerol by-product of biodiesel production from waste cooking oil, grease trap waste, and waste paper and, soon, locally collected pre- and post-consumer food residuals.

  19. The future of anaerobic digestion and biogas utilization.

    Science.gov (United States)

    Holm-Nielsen, J B; Al Seadi, T; Oleskowicz-Popiel, P

    2009-11-01

    One of the common tendencies of animal production activities in Europe and in developed countries in general is to intensify the animal production and to increase the size of the animal production units. High livestock density is always accompanied by production of a surplus of animal manure, representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel - the biogas. The EU policies concerning renewable energy systems (RES) have set forward a fixed goal of supplying 20% of the European energy demands from RES by year 2020. A major part of the renewable energy will originate from European farming and forestry. At least 25% of all bioenergy in the future can originate from biogas, produced from wet organic materials such as: animal manure, whole crop silages, wet food and feed wastes, etc.

  20. Treatment of wine distillery wastewater by high rate anaerobic digestion.

    Science.gov (United States)

    Melamane, X L; Tandlich, R; Burgess, I E

    2007-01-01

    Wine distillery wastewaters (WDW) are acidic and have a high content of potential organic pollutants. This causes high chemical oxygen demand (COD) values. Polyphenols constitute a significant portion of this COD, and limit the efficiency of biological treatment of WDWs. WDW starting parameters were as follows: pH 3.83, 4,185 mg/l soluble COD (COD(s)) and 674.6 mg/l of phenols. During operation, amendments of CaCO3 and K2HPO4, individually or in combination, were required for buffering the digester. Volatile fatty acid concentrations were < 300 mg/l throughout the study, indicating degradation of organic acids present. Mean COD(s) removal efficiency for the 130 day study was 87%, while the mean polyphenol, removal efficiency was 63%. Addition of 50 mg/l Fe(3+) between days 86 and 92 increased the removal efficiencies of COD(s) to 97% and of polyphenols to 65%. Addition of Co(3+) improved removal efficiencies to 97% for COD(s) and 92% for polyphenols. Optimization of anaerobic treatment was achieved at 30% WDW feed strength. Removal efficiencies of 92% and 84% were recorded at increased feed strength from days 108 to 130. High removal efficiencies of COD(s) and polyphenols after day 82 were attributed to the addition of macronutrients and micronutrients that caused pH stability and thus stimulated microbial activity.

  1. 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.

  2. EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Tülin Atan

    2013-01-01

    Full Text Available For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-based Anaerobic Sprint Test (RAST under 3 conditions on separate days: while listening to “slow rhythm music”, “fast rhythm music” or “no music”. 48 hours after the subjects completed RAST under 3 conditions, Wingate Anaerobic Power (WAN tests were performed under 3 music conditions. The order of the 3 conditions (slow music, fast music and no music was selected randomly to prevent an order effect. Results showed no significant differences between 3 conditions in anaerobic power assessments, heart rate or blood lactate (p>0.05. On the basis of these results it can be said that music cannot improve anaerobic performance. The type of music had no impact on power outputs during RAST and WAN exercise. As a conclusion, listening to music and its rhythm cannot enhance anaerobic performance and cannot change the physiological response to supramaximal exercise.

  3. 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.

  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. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  6. Impact of Organic Loading Rate on Psychrophilic Anaerobic Digestion of Solid Dairy Manure

    Directory of Open Access Journals (Sweden)

    Noori M. Cata Saady

    2015-03-01

    Full Text Available Increasing the feed total solids to anaerobic digester improves the process economics and decreases the volume of liquid effluent from current wet anaerobic digestion. The objective of this study was to develop a novel psychrophilic (20 °C anaerobic digestion technology of undiluted cow feces (total solids of 11%–16%. Two sets of duplicate laboratory-scale sequence batch bioreactors have been operated at organic loading rates (OLR of 6.0 to 8.0 g total chemical oxygen demand (TCOD kg−1 inoculum day−1 (d−1 during 210 days. The results demonstrated that the process is feasible at treatment cycle length (TCL of 21 days; however, the quality of cow feces rather than the OLR had a direct influence on the specific methane yield (SMY. The SMY ranged between 124.5 ± 1.4 and 227.9 ± 4.8 normalized liter (NL CH4 kg−1 volatile solids (VS fed d−1. Substrate-to-inoculum mass ratio (SIR was 0.63 ± 0.05, 0.90 ± 0.09, and 1.06 ± 0.07 at OLR of 6.0, 7.0, and 8.0 g TCOD kg−1 inoculum d−1, respectively. No volatile fatty acids (VFAs accumulation has been observed which indicated that hydrolysis was the rate limiting step and VFAs have been consumed immediately. Bioreactors performance consistency in terms of the level of SMYs, VFAs concentrations at end of the TCL, pH stability and volatile solids reduction indicates a stable and reproducible process during the entire operation.

  7. Optimization of anaerobic digestion of a mixture of Zea mays and Miscanthus sacchariflorus silages with various pig manure dosages.

    Science.gov (United States)

    Bułkowska, K; Pokój, T; Klimiuk, E; Gusiatin, Z M

    2012-12-01

    Digestion of crop silage (Zea mays L. and Miscanthus sacchariflorus) with 0%, 7.5%, 12.5% and 25% pig manure as co-substrate was performed in continuous stirred-tank reactors, for a constant hydraulic retention time of 45 d and organic load rate of 2.1 g L(-1)d(-1). A matrix of correlations between biogas/methane production and parameters of anaerobic digestion was created in order to estimate process stability. The values of the correlation coefficients indicated that the most stable anaerobic digestion was achieved using 7.5% and 12.5% pig manure. In contrast, the positive correlation between ammonium and volatile fatty acids (r=0.8698, psilage alone, pig manure favored the production of biogas and methane; the highest production rates were obtained with 12.5% pig manure.

  8. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions

    DEFF Research Database (Denmark)

    Johansen, Anders; Bangsø Nielsen, Henrik; Hansen, Christian M.

    2013-01-01

    did not affect egg survival during the first 48h and it took up to 10days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites......Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit...... from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs...

  9. Adaptive neuro-fuzzy modelling of anaerobic digestion of primary sedimentation sludge.

    Science.gov (United States)

    Cakmakci, Mehmet

    2007-09-01

    Modelling of anaerobic digestion systems is difficult because their performance is complex and varies significantly with influent characteristics and operational conditions. In this study, Adaptive Neuro-Fuzzy Inference System (ANFIS) were used for modelling of anaerobic digestion system of primary sludge of Kayseri municipal WasteWater Treatment Plant (WWTP). Effluent Volatile Solid (VS) and methane yield were predicted by the ANFIS. Two stage models were performed. In the first stage, effluent VS concentration was predicted using pH, VS concentration, flowrate of pre-thickened sludge and temperature of the influent as input parameters. In the second stage, effluent VS concentration in addition to first stage input parameters were used as input parameters to predict methane yield. The low Root Mean Square Error (RMSE) and high Index of agreement (IA) values were obtained with subtractive clustering method of a first order Sugeno type inference. The model performance was evaluated with statistical parameters. According to statistical evaluations, the models satisfactorily predict effluent VS concentration and methane yield.

  10. Increasing concentrations of phenol progressively affect anaerobic digestion of cellulose and associated microbial communities.

    Science.gov (United States)

    Chapleur, Olivier; Madigou, Céline; Civade, Raphaël; Rodolphe, Yohan; Mazéas, Laurent; Bouchez, Théodore

    2016-02-01

    Performance stability is a key issue when managing anaerobic digesters. However it can be affected by external disturbances caused by micropollutants. In this study the influence of phenol on the methanization of cellulose was evaluated through batch toxicity assays. Special attention was given to the dynamics of microbial communities by means of automated ribosomal intergenic spacer analysis. We observed that, as phenol concentrations increased, the different steps of anaerobic cellulose digestion were unevenly and progressively affected, methanogenesis being the most sensitive: specific methanogenic activity was half-inhibited at 1.40 g/L of phenol, whereas hydrolysis of cellulose and its fermentation to VFA were observed at up to 2.00 g/L. Depending on the level of phenol, microbial communities resisted either through physiological or structural adaptation. Thus, performances at 0.50 g/L were maintained in spite of the microbial community's shift. However, the communities' ability to adapt was limited and performances decreased drastically beyond 2.00 g/L of phenol.

  11. 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.

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

    Science.gov (United States)

    Kuo, Jeff; Dow, Jason

    2017-09-01

    quality and quantity of biogas from anaerobic co-digestion of food waste and municipal wastewater sludge, as well as impacts on air quality from biopower generation using this biogas. The need and performance of conditioning/pretreatment systems for biopower generation were also assessed.

  13. 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...

  14. State Of The Science On Cogeneration Of Heat And Power From Anaerobic Digestion Of Municipal Biosolids

    Science.gov (United States)

    This presentation will report on work underway to inventory facilities currently utilizing biogas from anaerobic digestion and speak with practitioners to learn: techniques for preparing residuals for digestion, methods to use for cleaning biogas (e.g., of siloxane), and how gas...

  15. Anaerobic Digestion II. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

    Science.gov (United States)

    Arasmith, E. E.

    This lesson is the second of a two-part series on anaerobic digestion. Topics discussed include classification of digester by function, roof design, and temperature range, mixing systems, gas system components, operational control basics, and general safety considerations. The lesson includes an instructor's guide and student workbook. The…

  16. State Of The Science On Cogeneration Of Heat And Power From Anaerobic Digestion Of Municipal Biosolids

    Science.gov (United States)

    This presentation will report on work underway to inventory facilities currently utilizing biogas from anaerobic digestion and speak with practitioners to learn: techniques for preparing residuals for digestion, methods to use for cleaning biogas (e.g., of siloxane), and how gas...

  17. The potential of surplus grass production as co-substrate for anaerobic digestion

    DEFF Research Database (Denmark)

    Meyer, Ane Katharina Paarup; Schleier, Caroline; Piorr, Hans Peter

    2016-01-01

    . Furthermore, it could provide incentives for establishing new biogas plants in the region and thereby increase the share of manure being digested anaerobically, which could help extrapolate the environmental and climate related benefits documented for the use of digested animal manure as fertilizer...

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

    Science.gov (United States)

    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.

  19. Characteristics of dissolved organic matter formed in aerobic and anaerobic digestion of excess activated sludge.

    Science.gov (United States)

    Du, Haixia; Li, Fusheng

    2017-02-01

    The characteristics of dissolved organic matter (DOM) formed in aerobic and anaerobic digestion of excess activated sludge (EAS) was investigated for three total solid (TS) concentrations (1.2, 2.3 and 5.2%) and three temperatures (5, 20 and 35 °C). The results on the overall concentration of DOM evaluated by TOC showed significantly higher values in anaerobic than aerobic digestion (2.8-6.9 times for TS 1.2-5.2% at 20 °C). Data analysis with a first-order sequential reaction model revealed that higher occurrence of DOM in anaerobic digestion was a result of comparatively faster hydrolysis (1.3-5.5 times for TS 1.2-5.2% at 20 °C; 1.4-49.3 times for temperatures 5-35 °C with TS 1.2%) and slower degradation (0.3-1.0 times for TS 1.2-5.2% at 20 °C; 0.5-8.3 times for temperatures 5-35 °C with TS 1.2%). In aerobic digestion, more humic substances were formed; while, in anaerobic digestion, proteins and aromatic amino acids were the major constituents. For both digestions, except for a few exceptions, proteins and humic substances increased as the TS concentration increased; and increasing the temperature led to a decrease in the content of proteins formed in both aerobic and anaerobic digestion, and an increase in the content of humic substances in the aerobic digestion. The UV-absorbing DOM constituents were highly heterogeneous, and were comparatively larger in anaerobic digestion; and did not change significantly with the TS concentrations and temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Techno-economic evaluation of stillage treatment with anaerobic digestion in a softwood-to-ethanol process

    Directory of Open Access Journals (Sweden)

    Barta Zsolt

    2010-09-01

    Full Text Available Abstract Background Replacing the energy-intensive evaporation of stillage by anaerobic digestion is one way of decreasing the energy demand of the lignocellulosic biomass to the ethanol process. The biogas can be upgraded and sold as transportation fuel, injected directly into the gas grid or be incinerated on-site for combined heat and power generation. A techno-economic evaluation of the spruce-to-ethanol process, based on SO2-catalysed steam pretreatment followed by simultaneous saccharification and fermentation, has been performed using the commercial flow-sheeting program Aspen Plus™. Various process configurations of anaerobic digestion of the stillage, with different combinations of co-products, have been evaluated in terms of energy efficiency and ethanol production cost versus the reference case of evaporation. Results Anaerobic digestion of the stillage showed a significantly higher overall energy efficiency (87-92%, based on the lower heating values, than the reference case (81%. Although the amount of ethanol produced was the same in all scenarios, the production cost varied between 4.00 and 5.27 Swedish kronor per litre (0.38-0.50 euro/L, including the reference case. Conclusions Higher energy efficiency options did not necessarily result in lower ethanol production costs. Anaerobic digestion of the stillage with biogas upgrading was demonstrated to be a favourable option for both energy efficiency and ethanol production cost. The difference in the production cost of ethanol between using the whole stillage or only the liquid fraction in anaerobic digestion was negligible for the combination of co-products including upgraded biogas, electricity and district heat.

  1. 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.

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

    Science.gov (United States)

    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.

  3. 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.

  4. Determination of Methane and Carbon Dioxide Formation Rate Constants for Semi-Continuously Fed Anaerobic Digesters

    Directory of Open Access Journals (Sweden)

    Jan Moestedt

    2015-01-01

    Full Text Available To optimize commercial-scale biogas production, it is important to evaluate the performance of each microbial step in the anaerobic process. Hydrolysis and methanogenesis are usually the rate-limiting steps during digestion of organic waste and by-products. By measuring biogas production and methane concentrations on-line in a semi-continuously fed reactor, gas kinetics can be evaluated. In this study, the rate constants of the fermentative hydrolysis step (kc and the methanogenesis step (km were determined and evaluated in a continuously stirred tank laboratory-scale reactor treating food and slaughterhouse waste and glycerin. A process additive containing Fe2+, Co2+ and Ni2+ was supplied until day 89, after which Ni2+ was omitted. The omission resulted in a rapid decline in the methanogenesis rate constant (km to 70% of the level observed when Ni2+ was present, while kc remained unaffected. This suggests that Ni2+ mainly affects the methanogenic rather than the hydrolytic microorganisms in the system. However, no effect was initially observed when using conventional process monitoring parameters such as biogas yield and volatile fatty acid concentration. Hence, formation rate constants can reveal additional information on process performance and km can be used as a complement to conventional process monitoring tools for semi-continuously fed anaerobic digesters.

  5. EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

    OpenAIRE

    Tülin Atan

    2013-01-01

    For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-...

  6. EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

    OpenAIRE

    Atan, T.

    2013-01-01

    For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-...

  7. Anaerobic Digestion and Biogas Potential: Simulation of Lab and Industrial-Scale Processes

    Directory of Open Access Journals (Sweden)

    Ihsan Hamawand

    2015-01-01

    Full Text Available In this study, a simulation was carried out using BioWin 3.1 to test the capability of the software to predict the biogas potential for two different anaerobic systems. The two scenarios included: (1 a laboratory-scale batch reactor; and (2 an industrial-scale anaerobic continuous lagoon digester. The measured data related to the operating conditions, the reactor design parameters and the chemical properties of influent wastewater were entered into BioWin. A sensitivity analysis was carried out to identify the sensitivity of the most important default parameters in the software’s models. BioWin was then calibrated by matching the predicted data with measured data and used to simulate other parameters that were unmeasured or deemed uncertain. In addition, statistical analyses were carried out using evaluation indices, such as the coefficient of determination (R-squared, the correlation coefficient (r and its significance (p-value, the general standard deviation (SD and the Willmott index of agreement, to evaluate the agreement between the software prediction and the measured data. The results have shown that after calibration, BioWin can be used reliably to simulate both small-scale batch reactors and industrial-scale digesters with a mean absolute percentage error (MAPE of less than 10% and very good values of the indexes. Furthermore, by changing the default parameters in BioWin, which is a way of calibrating the models in the software, as well, this may provide information about the performance of the digester. Furthermore, the results of this study showed there may be an over estimation for biogas generated from industrial-scale digesters. More sophisticated analytical devices may be required for reliable measurements of biogas quality and quantity.

  8. Anaerobic Slurry Co-Digestion of Poultry Manure and Straw: Effect of Organic Loading and Temperature

    Directory of Open Access Journals (Sweden)

    Azadeh Babaee

    2013-07-01

    Full Text Available In order to obtain basic design criteria for anaerobic digestion of a mixture of poultry manure and wheat straw, the effects of different temperatures and organic loading rates on the biogas yield and methane contents were evaluated. Since poultry manure is a poor substrate, in term of the availability of the nutrients, external supplementation of carbon has to be regularly performed, in order to achieve a stable and efficient process. The complete-mix, pilot-scale digester with working volume of 70 L was used. The digestion operated at 25[degree sign]C, 30[degree sign]C and 35[degree sign]C with organic loading rates of 1.0, 2.0, 2.5, 3.0, 3.5 and 4.0 kg Volatile solid/m3d and a HRT of 15 days. At a temperature of 35[degree sign]C, the methane yield was increased by 43% compared to 25[degree sign]C. Anaerobic co-digestion appeared feasible with a loading rate of 3.0 kg VS/m3d at 35[degree sign]C. At this state, the specific methane yield was calculated about 0.12 m3/kg VS with a methane content of 53--70.2% in the biogas. The volatile solid (VS removal was 72%. As a result of volatile fatty acid accumulation and decrease in pH, when the loading rate was less than 1 or greater than 4 kg VS/m3d, the process was inhibited or overloaded, respectively. Both the lower and higher loading rates resulted in a decline in the methane yield.

  9. 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.

  10. Influence of pretreatment techniques on anaerobic digestion of pulp and paper mill sludge: A review.

    Science.gov (United States)

    Veluchamy, C; Kalamdhad, Ajay S

    2017-09-01

    Pulp and paper industry is one of the most polluting, energy and water intensive industries in the world. Produced pulp and paper mill sludge (PPMS) faces a major problem for handling and its management. An anaerobic digestion has become an alternative source. This review provides a detailed summary of anaerobic digestion of PPMS - An overview of the developments and improvement opportunities. This paper explores the different pretreatment methods to enhance biogas production from the PPMS. First, the paper gives an overview of PPMS production, and then it reviews PPMS as a substrate for anaerobic digestion with or without pretreatment. Finally, it discuss the optimal condition and concentration of organic and inorganic compounds required for the anaerobic metabolic activity. Future research should focus on the combination of different pretreatment technologies, relationship between sludge composition, reactor design and its operation, and microbial community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. SLEEP DEPRIVATION INDUCED ANXIETY AND ANAEROBIC PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Selma Arzu Vardar

    2007-12-01

    Full Text Available The aim of this study was to investigate the effects of sleep deprivation induced anxiety on anaerobic performance. Thirteen volunteer male physical education students completed the Turkish version of State Anxiety Inventory and performed Wingate anaerobic test for three times: (1 following a full-night of habitual sleep (baseline measurements, (2 following 30 hours of sleep deprivation, and (3 following partial-night sleep deprivation. Baseline measurements were performed the day before total sleep deprivation. Measurements following partial sleep deprivation were made 2 weeks later than total sleep deprivation measurements. State anxiety was measured prior to each Wingate test. The mean state anxiety following total sleep deprivation was higher than the baseline measurement (44.9 ± 12.9 vs. 27.6 ± 4.2, respectively, p = 0.02 whereas anaerobic performance parameters remained unchanged. Neither anaerobic parameters nor state anxiety levels were affected by one night partial sleep deprivation. Our results suggest that 30 hours continuous wakefulness may increase anxiety level without impairing anaerobic performance, whereas one night of partial sleep deprivation was ineffective on both state anxiety and anaerobic performance

  12. AMMONIA INHIBITION IN THERMOPHILIC ANAEROBIC DIGESTION OF DAIRY CATTLE MANURE

    Directory of Open Access Journals (Sweden)

    S. Sutaryo

    2015-04-01

    Full Text Available This study investigated the effect of five different concentrations of total ammonia nitrogen (TANand free ammonia (FA on the methane yield and digester performance under thermophilic conditions(50°C. Five identical continuously fed digesters were used. The experiment was run for four timeshydraulic retention time (HRT. Data were statitically analysed using the data Analysis Tool Packavailable with the Microsoft Excel program. Different ammonia levels were obtained by pulsing urea toobtain the target level of TAN and FA, and to subsequently maintaining the concentration of ammonialevels by daily urea additions. The result showed a strong negative correlation between both TAN andFA concentrations and methane yield. The methane yield was reduced by 24, 30, 52 and 66% indigesters that had TAN levels of 2.9, 3.6, 4.4 and 5.1 g/L, respectively, corresponding to 0.7, 1.1,1.5 and1.8 g/L FA. Total volatile fatty acid and especially isovaleric and isobutyric acid concentrations wereelevated during ammonia inhibition. Concentration of TAN in the biogas digester exceeding 3 g/Lindicating that very often the full biogas potential is not achieved due to ammonia inhibition and thatlonger HRT should be used to compensate or a lower process temperature should be chosen.

  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. Microbial trophic interactions and mcrA gene expression in monitoring of anaerobic digesters

    Science.gov (United States)

    Alvarado, Alejandra; Montañez-Hernández, Lilia E.; Palacio-Molina, Sandra L.; Oropeza-Navarro, Ricardo; Luévanos-Escareño, Miriam P.; Balagurusamy, Nagamani

    2014-01-01

    Anaerobic digestion (AD) is a biological process where different trophic groups of microorganisms break down biodegradable organic materials in the absence of oxygen. A wide range of AD technologies is being used to convert livestock manure, municipal and industrial wastewaters, and solid organic wastes into biogas. AD gains importance not only because of its relevance in waste treatment but also because of the recovery of carbon in the form of methane, which is a renewable energy and is used to generate electricity and heat. Despite the advances on the engineering and design of new bioreactors for AD, the microbiology component always poses challenges. Microbiology of AD processes is complicated as the efficiency of the process depends on the interactions of various trophic groups involved. Due to the complex interdependence of microbial activities for the functionality of the anaerobic bioreactors, the genetic expression of mcrA, which encodes a key enzyme in methane formation, is proposed as a parameter to monitor the process performance in real time. This review evaluates the current knowledge on microbial groups, their interactions, and their relationship to the performance of anaerobic biodigesters with a focus on using mcrA gene expression as a tool to monitor the process. PMID:25429286

  15. 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.

  16. Computer-aided design model for anaerobic-phased-solids digester system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Zhang, R. [University of California, Davis, CA (United States); Tiangco, V. [California Energy Commission, Sacramento, CA (United States)

    1999-07-01

    The anaerobic-phased-solids (APS) digester system is a newly developed anaerobic digestion system for converting solid wastes, such as crop residues and food wastes, into biogas for power and heat generation. A computer-aided engineering design model has been developed to design the APS-digester system and study the heat transfer from the reactors and energy production of the system. Simulation results of a case study are presented by using the model to predict the heating energy requirement and biogas energy production for anaerobic digestion of garlic waste. The important factors, such as environmental conditions, insulation properties, and characteristics of the wastes, on net energy production are also investigated. (author)

  17. Ammonia and temperature determine potential clustering in the anaerobic digestion microbiome.

    Science.gov (United States)

    De Vrieze, Jo; Saunders, Aaron Marc; He, Ying; Fang, Jing; Nielsen, Per Halkjaer; Verstraete, Willy; Boon, Nico

    2015-05-15

    Anaerobic digestion is regarded as a key environmental technology in the present and future bio-based economy. The microbial community completing the anaerobic digestion process is considered complex, and several attempts already have been carried out to determine the key microbial populations. However, the key differences in the anaerobic digestion microbiomes, and the environmental/process parameters that drive these differences, remain poorly understood. In this research, we hypothesized that differences in operational parameters lead to a particular composition and organization of microbial communities in full-scale installations. A total of 38 samples were collected from 29 different full-scale anaerobic digestion installations, showing constant biogas production in function of time. Microbial community analysis was carried out by means of amplicon sequencing and real-time PCR. The bacterial community in all samples was dominated by representatives of the Firmicutes, Bacteroidetes and Proteobacteria, covering 86.1 ± 10.7% of the total bacterial community. Acetoclastic methanogenesis was dominated by Methanosaetaceae, yet, only the hydrogenotrophic Methanobacteriales correlated with biogas production, confirming their importance in high-rate anaerobic digestion systems. In-depth analysis of operational and environmental parameters and bacterial community structure indicated the presence of three potential clusters in anaerobic digestion. These clusters were determined by total ammonia concentration, free ammonia concentration and temperature, and characterized by an increased relative abundance of Bacteroidales, Clostridiales and Lactobacillales, respectively. None of the methanogenic populations, however, could be significantly attributed to any of the three clusters. Nonetheless, further experimental research will be required to validate the existence of these different clusters, and to which extent the presence of these clusters relates to stable or sub

  18. A generic and systematic procedure to derive a simplified model from the Anaerobic Digestion Model No. 1 (ADM1)

    OpenAIRE

    Ficara, E.; Leva, A.; Harmand, Jérôme

    2015-01-01

    The Anaerobic Digestion Model No.1 (ADM1) developed by the IWA Task Group for mathematical modelling of anaerobic digestion processes (Batstone et al. (2001) [1]) is a structural model which describes the main biochemical and physicochemical processes. For such purposes, other models have been proposed to describe anaerobic processes with a reduced set of parameters, state variables and processes. Among them, the Anaerobic Model No. 2 (AM2) proposed by Bernard et al. (2001) [2] which describe...

  19. A pilot study of anaerobic membrane digesters for concurrent thickening and digestion of waste activated sludge (WAS).

    Science.gov (United States)

    Dagnew, Martha; Parker, Wayne J; Seto, Peter

    2010-01-01

    The increased interest in biomass energy provides incentive for the development of efficient and high throughput digesters such as anaerobic membrane bioreactors (AnMBRs) to stabilize waste activated sludge (WAS). This paper presents the results of a pilot and short term filtration study that was conducted to assess the performance of AnMBRs when treating WAS at a 15 day hydraulic retention time (HRT) and 30 day sludge retention time (SRT) in comparison to two conventional digesters running at 15 (BSR-15) and 30 days (BSR-30) HRT/SRT. At steady state, the AnMBR digester showed a slightly higher volatile solids (VS) destruction of 48% in comparison to 44% and 35.3% for BSR-30 and BSR-15, respectively. The corresponding values of specific methane production were 0.32, 0.28 and 0.21 m(3) CH(4)/kg of VS fed. Stable membrane operation at an average flux of 40+/-3.6 LM(-2 )H(-1) (LMH) was observed when the digester was fed with a polymer-dosed thickened waste activated sludge (TWAS) and digester total suspended solids (TSS) concentrations were less than 15 gL(-1). Above this solids concentration a flux decline to 24.1+/-2.0 LM(-2) H(-1) was observed. Short term filtration tests conducted using sludge fractions of a 9.7 and 17.1 gL(-1) TSS sludge indicated 84 and 70% decline in filtration performance to be associated with the supernatant fraction of the sludge. At a higher sludge concentration, the introduction of unique fouling control strategy to tubular membranes, a relaxed mode of operation (i.e. 5 minutes permeation and 1 minute relaxation by) significantly increased the flux from 23.8+/-1.1 to 37.8+/-2.3 LMH for a neutral membrane and from 25.7+/-1.1 to 44.9+/-2.9 LMH for a negatively charged membrane. The study clearly indicates that it is technically feasible to employ AnMBRs to achieve a substantial reduction in digester volumes.

  20. Pb(II) biosorption using anaerobically digested sludge.

    Science.gov (United States)

    Tokcaer, Emre; Yetis, Ulku

    2006-10-11

    Removal of Pb(II) by using resting cells of anaerobically digested sludge (ADS) obtained from a nearby wastewater treatment plant was examined. Firstly, sorption kinetic and equilibrium experiments were conducted using agitated, thermostated (25 degrees C) batch reactors. The maximum Pb(II) sorption capacity was found to be very high (1,750 mg/g dry ADS or 8.45 mmol/g dry ADS). At all initial Pb(II) concentrations tested, sorption resulted in neutralization with an increase in the solution pH from an initial value of 4.0-5.5 to an equilibrium value of 7.0-8.0, at which Pb(II) can precipitate as hydroxide. The removal of Pb(II) by ADS was found to involve bioprecipitation as well as biosorption. FTIR spectrometry highlighted carboxyl groups present on the surface of ADS as the major functional groups responsible for biosorption. Secondly, a three-stage semi-continuous pseudo-counter current reactor system was tested to reduce ADS requirement in comparison to a conventional single-stage batch reactor. At an initial Pb(II) concentration of about 200 mg/L, an effluent Pb(II) concentration of 1.3 mg/L was achieved in the three stage reactor, corresponding to a metal removal capacity of 682.7 mg/g dry ADS (3.30 mmol/g), in comparison to 1.9 mg/L and 644.0 mg/g dry ADS (3.10 mmol/g) for the single-stage batch reactor.

  1. The Effect of Iron Salt on Anaerobic Digestion and Phosphate Release to Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Svetlana Ofverstrom

    2011-12-01

    Full Text Available Iron salts are used at wastewater treatment plants (WWTPs for several reasons: for removing chemical phosphorus, preventing from struvite formation and reducing the content of hydrogen sulfide (H2S in biogas. Anaerobic digestion is a common scheme for sludge treatment due to producing biogas that could be used as biofuel. Laboratory analysis has been carried out using anaerobic digestion model W8 (Armfield Ltd, UK to investigate any possible effect of adding FeCl3 on the anaerobic digestion of primary sludge (PS and waste activated sludge (WAS mixture as well as on releasing phosphates to digested sludge liquor. The obtained results showed that FeCl3 negatively impacted the anaerobic digestion process by reducing the volume of produced biogas. Fe-dosed sludge (max produced 30% less biogas. Biogas production from un-dosed and Fe-dosed sludge (min was similar to the average of 1.20 L/gVSfed. Biogas composition was not measured during the conducted experiments. Phosphorus content in sludge liquor increased at an average of 38% when digesting sludge without ferric chloride dosing. On the contrary, phosphate content in sludge liquor from digested Fe-dosed sludge decreased by approx. 80%.

  2. Pilot Scale Study on Two-phase Anaerobic Digestion Performance of Kitchen Waste%餐厨垃圾两相厌氧消化特性试验研究

    Institute of Scientific and Technical Information of China (English)

    熊杰; 袁海荣; 王奎升; 朱保宁; 刘研萍; 邹德勋; 党峰; 李秀金

    2012-01-01

    Two-phase anaerobic digestion performance of kitchen waste was investigated with different organic loading rate (OLR) of 10, 30, 50 and 70 gVS/L, inoculums dosages of 5, 10, 15 and 20 gVS/L, acidification times of 3, 5, 7 and 9 d by orthogonal experiment design. Kitchen waste from campus restaurant was used as feedstock. Results showed that kitchen waste obtained the best acidification results with 30 gVS/L of OLR, 15 gVS/L of inoculums dosage and 5 day of acidification time. The acid yield of kitchen waste was 561.0 mg acetic acid.gVS/L mainly acetate and butyrate. Total biogas yield was 826.7 mL/gVS, which was 8.2% and 1,070.3% higher than ethanol type fermentation of 763.8 mL/gVS in the best condition, and butyrate type fermentation of 70.6 mL/gVS in the worst condition respectively. Therefore OLR, acidification time and inoculums dosage have important influence on acidification and methane of kitchen waste. The study would provide parameters for effective operation and optimal design of anaerobic digestion facility of municipal organic solid waste.%研究了餐厨垃圾两相厌氧消化特性.以北京化工大学餐厨垃圾为原料,分别以不同有机负荷(10、30、50和70 gVS/L)、接种量(5、10、15和20 gVS/L)、酸化时间(3、5、7和9d)考察其对酸化效果的影响,并对酸化出料进行甲烷化产气实验.结果表明,餐厨垃圾最优酸化条件为有机负荷30 gVS/L,酸化时间5d,接种量15 gVS/L.在此条件下,单位负荷产酸率为561.0 mg乙酸gVS,酸化末端产物主要为乙酸和丁酸,单位负荷累积产气量达到826.7 mL/gVS,比乙醇型最佳条件单位负荷累积产气量763.8 mL/gVS高8.2%,比丁酸型最低单位负荷累积产气量70.6 mL/gVS高1 070.3%.有机负荷、酸化时间、接种量依次对餐厨垃圾酸化有重要的影响,并且餐厨垃圾酸化效果和产气性能具有一致性.研究结果可为城市生活垃圾厌氧消化提供设计和运行依据.

  3. 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.

  4. Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process.

    Science.gov (United States)

    Zonta, Z; Alves, M M; Flotats, X; Palatsi, J

    2013-03-01

    Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association's Anaerobic Digestion Model N°1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced, providing a plausible explanation of experimental based hypothesis.

  5. 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.

  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. Toxicity of linear alkylbenzene sulfonate in anaerobic digestion: influence of exposure time.

    Science.gov (United States)

    Mösche, M; Meyer, U

    2002-07-01

    The inhibition of anaerobic digestion by the anionic surfactant linear alkylbenzene sulfonate was studied. The development of bacterial activity during several weeks was monitored by performing batch degradation tests with acetate and propionate. In the first phase the decay of activity without surfactant addition was studied. After the addition of the surfactant an immediate inhibition was detected. Subsequently, the degradation activity continued to decrease with increasing exposure time. Both, the immediate inhibition and the rate of the subsequent decrease of activity were dependent on the surfactant concentration. A kinetic model is presented that describes this behavior. A surfactant concentration of 14 mg L(-1) causes a 50% immediate inhibition of acetate degradation (27 mg L(-1) in the case of propionate degradation). Additionally, each 12 mg L(-1) of surfactant increases the decay rate of acetate degradation activity by a factor 10 (23 mg L(-1) for propionate degradation). A deviation from this model occurs at low surfactant concentrations (<3 mg L(-1)), where a slight stimulation of bacterial activity was observed. The above-mentioned concentrations refer to measured surfactant concentrations. These were substantially lower than the nominal concentrations (added surfactant per volume). This discrepancy is explained by adsorption of the surfactant to the biomass. Finally, the importance of the presented kinetic model and the significance of surfactant toxicity for anaerobic digestion are discussed.

  8. The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

    Directory of Open Access Journals (Sweden)

    Karthik Rajendran

    2013-06-01

    Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

  9. Anaerobic treatment of Tequila vinasses in a CSTR-type digester.

    Science.gov (United States)

    Méndez-Acosta, Hugo Oscar; Snell-Castro, Raúl; Alcaraz-González, Víctor; González-Alvarez, Víctor; Pelayo-Ortiz, Carlos

    2010-06-01

    Tequila industries in general produce great volumes of effluents with high pollutant loads, which are discharged (untreated or partially treated) into natural receivers, thus causing severe environmental problems. In this contribution, we propose an integrated system as a first step to comply with the Mexican ecological norms and stabilize the anaerobic treatment of Tequila vinasses with main design criteria: simple and easy operation, reduce operating time and associated costs (maintenance), integrated and compact design, minimal cost of set-up, start-up, monitoring and control. This system is composed of a fully instrumented and automated lab-scale CSTR-type digester, on-line measuring devices of key variables (pH, temperature, flow rates, etc.), which are used along with off-line readings of chemical oxygen demand (COD), biogas composition, alkalinity and volatile fatty acids to guarantee the operational stability of the anaerobic digestion process. The system performance was evaluated for 200 days and the experimental results show that even under the influence of load disturbances, it is possible to reduce the COD concentration to 85% in the start-up phase and up to 95% during the normal operation phase while producing a biogas with a methane composition greater than 65%. It is also shown that in order to maintain an efficient treatment, the buffering capacity (given by the alkalinity ratio, alpha = intermediate alkalinity/total alkalinity) must be closely monitored.

  10. Scale effect of anaerobic digestion tests in fed-batch and semi-continuous mode for the technical and economic feasibility of a full scale digester.

    Science.gov (United States)

    Ruffino, Barbara; Fiore, Silvia; Roati, Chiara; Campo, Giuseppe; Novarino, Daniel; Zanetti, Mariachiara

    2015-04-01

    Methane production capacity in mesophilic conditions of waste from two food industry plants was assessed in a semi-pilot (6L, fed-batch) and pilot (300 L, semi-continuous) scale. This was carried out in order to evaluate the convenience of producing heat and electricity in a full scale anaerobic digester. The pilot test was performed in order to obtain more reliable results for the design of the digester. Methane yield, returned from the pilot scale test, was approximately 80% of that from the smaller scale test. This outcome was in line with those from other studies performed in different scales and modes and indicates the success of the pilot scale test. The net electricity produced from the digester accounted for 30-50% of the food industry plants' consumption. The available thermal energy could cover from 10% to 100% of the plant requirements, depending on the energy demand of the processes performed.

  11. Improving anaerobic sewage sludge digestion by implementation of a hyper-thermophilic prehydrolysis step

    DEFF Research Database (Denmark)

    Lu, Jingquan; Gavala, Hariklia N.; Skiadas, Ioannis V.

    2008-01-01

    The present study focuses on a two-step process for treatment and stabilisation of primary sludge. The process consists of a hyperthermophilic hydrolysis step operated at 70 degrees C and a hydraulic retention time (HRT) of 2 clays followed by a thermophilic (55 degrees C) anaerobic digestion step...... at a HRT of 13 days. A one-step anaerobic digester operated at 55 degrees C and 15 days HRT Was used as a reference process. The two-step process was characterized by a 12% higher organic suspended solids removal efficiency and better pathogen reduction effect than the conventional one-step digestion....... The microbial community of the digester fed with pre-treated sludge was characterised by it higher activity compared to that of the digester treating raw sludge. Moreover, the pre-treatment of the primary sludge resulted up to 48% increase of the methane potential (20.09 and 13.56 mmol CH4 g(-)VS(-1...

  12. Phylogenetic diversity and in situ detection of eukaryotes in anaerobic sludge digesters

    Science.gov (United States)

    Matsubayashi, Miri; Shimada, Yusuke; Li, Yu-You; Harada, Hideki

    2017-01-01

    Eukaryotic communities in aerobic wastewater treatment processes are well characterized, but little is known about them in anaerobic processes. In this study, abundance, diversity and morphology of eukaryotes in anaerobic sludge digesters were investigated by quantitative real-time PCR (qPCR), 18S rRNA gene clone library construction and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). Samples were taken from four different anaerobic sludge digesters in Japan. Results of qPCR of rRNA genes revealed that Eukarya accounted from 0.1% to 1.4% of the total number of microbial rRNA gene copy numbers. The phylogenetic affiliations of a total of 251 clones were Fungi, Alveolata, Viridiplantae, Amoebozoa, Rhizaria, Stramenopiles and Metazoa. Eighty-five percent of the clones showed less than 97.0% sequence identity to described eukaryotes, indicating most of the eukaryotes in anaerobic sludge digesters are largely unknown. Clones belonging to the uncultured lineage LKM11 in Cryptomycota of Fungi were most abundant in anaerobic sludge, which accounted for 50% of the total clones. The most dominant OTU in each library belonged to either the LKM11 lineage or the uncultured lineage A31 in Alveolata. Principal coordinate analysis indicated that the eukaryotic and prokaryotic community structures were related. The detection of anaerobic eukaryotes, including the members of the LKM11 and A31 lineages in anaerobic sludge digesters, by CARD-FISH revealed their sizes in the range of 2–8 μm. The diverse and uncultured eukaryotes in the LKM11 and the A31 lineages are common and ecologically relevant members in anaerobic sludge digester. PMID:28264042

  13. Organics Characteristics of Sludge from a Full-Scale Anaerobic Digester Treating Domestic Mixed Sewage Sludge

    Directory of Open Access Journals (Sweden)

    Seswoya Roslinda

    2017-01-01

    Full Text Available Sewage sludge, normally in form of mixed sewage sludge is treated using anaerobic digester worldwide. In Malaysia, sewage sludge was categorized as domestic sewage sludge since sewage treatment plant treats only domestic sewage. The complex organic compounds in form of carbohydrates and proteins are transformed to methane during anaerobic digestion. The characteristics of complex organic compounds in domestic mixed sewage sludge are needed to assess the energy recovery form digesting domestic mixed sewage sludge. Besides that, it is common to use anaerobic biomass from existing anaerobic digester for the new setup of the anaerobic reactor. Therefore, this study was outlined to study the characteristics of domestic mixed sewage sludge and anaerobic biomass, particularly on the complex organic compounds. The complex organic compounds measured were carbohydrates and proteins. The higher complex organic solubilisation as a result of thermal pre-treatment was proven to improve the methane production. Therefore, in this study, the impact of low thermal pre-treatment in improving the organics solubilisation was assessed too. Low thermal pre-treatment at 70°C and 90°C at various treatment time were applied to the domestic mixed sewage sludge. The results indicated that the domestic sewage sludge and anaerobic biomass from a full-scale anaerobic digester contained complex organic compounds; existed mostly in form of particulate as shown by the low value of soluble to total ratio. Besides that, the low thermal treatment at 70°C and 90°C increased the organics solubilisation. Protein solubilisation was observed exceeded 8% after being treated for 20 min at both thermal treatments. However, the impact of low thermal treatment was better at 90°C, in which higher solubilisation was observed at longer treatment time.

  14. Ultrasonic and Thermal Pretreatments on Anaerobic Digestion of Petrochemical Sludge: Dewaterability and Degradation of PAHs.

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    Full Text Available Effects of different pretreatment methods on sludge dewaterability and polycyclic aromatic hydrocarbons (PAHs degradation during petrochemical sludge anaerobic digestion were studied. Results showed that the total biogas production volume in the thermal pretreatment system was 4 and 5 times higher than that in the ultrasound pretreatment and in the control system, and the corresponding volatile solid removal efficiencies reached 28%, 15%, and 8%. Phenanthrene, paranaphthalene, fluoranthene, benzofluoranthene, and benzopyrene removal rates reached 43.3%, 55.5%, 30.6%, 42.9%, and 41.7%, respectively, in the thermal pretreatment system, which were much higher than those in the ultrasound pretreatment and in the control system. Moreover, capillary suction time (CST of sludge increased after pretreatment, and then reduced after 20 days of anaerobic digestion, indicating that sludge dewaterability was greatly improved after anaerobic digestion. The decrease of protein and polysaccharide in the sludge could improve sludge dewaterability during petrochemical sludge anaerobic digestion. This study suggested that thermal pretreatment might be a promising enhancement method for petrochemical sludge solubilization, thus contributing to degradation of the PAHs, biogas production, and improvement of dewaterability during petrochemical sludge anaerobic digestion.

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

    Science.gov (United States)

    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.

  16. Ultrasonic and Thermal Pretreatments on Anaerobic Digestion of Petrochemical Sludge: Dewaterability and Degradation of PAHs

    Science.gov (United States)

    Zhou, Jun; Xu, Weizhong; Wong, Jonathan W. C.; Yong, Xiaoyu; Yan, Binghua; Zhang, Xueying; Jia, Honghua

    2015-01-01

    Effects of different pretreatment methods on sludge dewaterability and polycyclic aromatic hydrocarbons (PAHs) degradation during petrochemical sludge anaerobic digestion were studied. Results showed that the total biogas production volume in the thermal pretreatment system was 4 and 5 times higher than that in the ultrasound pretreatment and in the control system, and the corresponding volatile solid removal efficiencies reached 28%, 15%, and 8%. Phenanthrene, paranaphthalene, fluoranthene, benzofluoranthene, and benzopyrene removal rates reached 43.3%, 55.5%, 30.6%, 42.9%, and 41.7%, respectively, in the thermal pretreatment system, which were much higher than those in the ultrasound pretreatment and in the control system. Moreover, capillary suction time (CST) of sludge increased after pretreatment, and then reduced after 20 days of anaerobic digestion, indicating that sludge dewaterability was greatly improved after anaerobic digestion. The decrease of protein and polysaccharide in the sludge could improve sludge dewaterability during petrochemical sludge anaerobic digestion. This study suggested that thermal pretreatment might be a promising enhancement method for petrochemical sludge solubilization, thus contributing to degradation of the PAHs, biogas production, and improvement of dewaterability during petrochemical sludge anaerobic digestion. PMID:26327510

  17. Computational fluid dynamics investigation of turbulence models for non-newtonian fluid flow in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin

    2010-12-01

    In this paper, 12 turbulence models for single-phase non-newtonian fluid flow in a pipe are evaluated by comparing the frictional pressure drops obtained from computational fluid dynamics (CFD) with those from three friction factor correlations. The turbulence models studied are (1) three high-Reynolds-number k-ε models, (2) six low-Reynolds-number k-ε models, (3) two k-ω models, and (4) the Reynolds stress model. The simulation results indicate that the Chang-Hsieh-Chen version of the low-Reynolds-number k-ε model performs better than the other models in predicting the frictional pressure drops while the standard k-ω model has an acceptable accuracy and a low computing cost. In the model applications, CFD simulation of mixing in a full-scale anaerobic digester with pumped circulation is performed to propose an improvement in the effective mixing standards recommended by the U.S. EPA based on the effect of rheology on the flow fields. Characterization of the velocity gradient is conducted to quantify the growth or breakage of an assumed floc size. Placement of two discharge nozzles in the digester is analyzed to show that spacing two nozzles 180° apart with each one discharging at an angle of 45° off the wall is the most efficient. Moreover, the similarity rules of geometry and mixing energy are checked for scaling up the digester.

  18. Anaerobic co-digestion of the marine microalga Nannochloropsis salina with energy crops.

    Science.gov (United States)

    Schwede, Sebastian; Kowalczyk, Alexandra; Gerber, Mandy; Span, Roland

    2013-11-01

    Anaerobic co-digestion of corn silage with the marine microalga Nannochloropsis salina was investigated under batch and semi-continuous conditions. Under batch conditions process stability and biogas yields significantly increased by microalgae addition. During semi-continuous long-term experiments anaerobic digestion was stable in corn silage mono- and co-digestion with the algal biomass for more than 200 days. At higher organic loading rates (4.7 kg volatile solids m(-3)d(-1)) inhibition and finally process failure occurred in corn silage mono-digestion, whereas acid and methane formation remained balanced in co-digestion. The positive influences in co-digestion can be attributed to an adjusted carbon to nitrogen ratio, enhanced alkalinity, essential trace elements and a balanced nutrient composition. The results suggest that N. salina biomass is a suitable feedstock for anaerobic co-digestion of energy crops, especially for regions with manure scarcity. Enhanced process stability may result in higher organic loading rates or lower digester volumes.

  19. Anaerobic digestion of recalcitrant textile dyeing sludge with alternative pretreatment strategies.

    Science.gov (United States)

    Xiang, Xinyi; Chen, Xiaoguang; Dai, Ruobin; Luo, Ying; Ma, Puyue; Ni, Shengsheng; Ma, Chengyu

    2016-12-01

    Abundant organic compounds in textile dyeing sludge (TDS) provide possibility for its anaerobic digestion (AD) treatment. However, preliminary test showed little biogas generation in direct AD of the TDS during 20days. In order to improve the AD availability of TDS, alkaline, acid, thermal and thermal alkaline pretreatments were performed. Color and aromatic amines were specifically measured as extra characteristics for the AD of TDS. The rate-limiting steps of AD of TDS were slow hydrolysis rate and inhibited acidogenesis, which were somewhat overcome by pretreatments. Thermal alkaline pretreated TDS performed best enhancement on solubilisation. The biochemical methane potential tests revealed that thermal pretreated TDS showed highest total methane production of 55.9mL/gVSfed compared to the control with little methane generation. However, thermal alkaline pretreated TDS did not perform well in BMP test as expected. Moreover, the hydrophilicity of reactive dyes in TDS could seriously affect dewaterability of TDS.

  20. 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.