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Sample records for improves anaerobic biodegradability

  1. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors...

  2. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen

    2009-03-01

    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  3. Anaerobic Biodegradation of Detergent Surfactants

    OpenAIRE

    Erich Jelen; Ute Merrettig-Bruns

    2009-01-01

    Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have str...

  4. Thermal wet oxidation improves anaerobic biodegradability of raw and digested biowaste

    DEFF Research Database (Denmark)

    Lissens, G.; Thomsen, Anne Belinda; De Baere, L.;

    2004-01-01

    profits. The objective of this research was to enhance the anaerobic biodegradability and methane yields from different biowastes (food waste, yard waste, and digested biowaste already treated in a full-scale biogas plant (DRANCO, Belgium)) by assessing thermal wet oxidation. The biodegradability...... of the waste was evaluated by using biochemical methane potential assays and continuous 3-L methane reactors. Wet oxidation temperature and oxygen pressure (T, 185-220 degreesC; O-2 pressure, 0-12 bar; t, 15 min) were varied for their effect on total methane yield and digestion kinetics of digested biowaste....... Measured methane yields for raw yard waste, wet oxidized yard waste, raw food waste, and wet oxidized food waste were 345, 685, 536, and 571 mL of CH4/g of volatile suspended solids, respectively. Higher oxygen pressure during wet oxidation of digested biowaste considerably increased the total methane...

  5. Biodegradability of leathers through anaerobic pathway.

    Science.gov (United States)

    Dhayalan, K; Fathima, N Nishad; Gnanamani, A; Rao, J Raghava; Nair, B Unni; Ramasami, T

    2007-01-01

    Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers.

  6. 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.

  7. Improve the Anaerobic Biodegradability by Copretreatment of Thermal Alkali and Steam Explosion of Lignocellulosic Waste

    Directory of Open Access Journals (Sweden)

    Muhammad Abdul Hanan Siddhu

    2016-01-01

    Full Text Available Effective alteration of the recalcitrance properties like crystallization of cellulose, lignin shield, and interlinking of lignocellulosic biomass is an ideal way to utilize the full-scale potential for biofuel production. This study exhibited three different pretreatment effects to enhance the digestibility of corn stover (CS for methane production. In this context, steam explosion (SE and thermal potassium hydroxide (KOH-60°C treated CS produced the maximal methane yield of 217.5 and 243.1 mL/gvs, which were 40.0% and 56.4% more than untreated CS (155.4 mL/gvs, respectively. Copretreatment of thermal potassium hydroxide and steam explosion (CPTPS treated CS was highly significant among all treatments and improved 88.46% (292.9 mL/gvs methane yield compared with untreated CS. Besides, CPTPS also achieved the highest biodegradability up to 68.90%. Three kinetic models very well simulated dynamics of methane production yield. Moreover, scanning electron microscopy (SEM, Fourier transform infrared (FTIR, and X-ray diffraction (XRD analyses declared the most effective changes in physicochemical properties after CPTPS pretreatment. Thus, CPTPS might be a promising approach to deconstructing the recalcitrance of lignocellulosic structure to improve the biodegradability for AD.

  8. Improve the Anaerobic Biodegradability by Copretreatment of Thermal Alkali and Steam Explosion of Lignocellulosic Waste.

    Science.gov (United States)

    Siddhu, Muhammad Abdul Hanan; Li, Jianghao; Zhang, Jiafu; Huang, Yan; Wang, Wen; Chen, Chang; Liu, Guangqing

    2016-01-01

    Effective alteration of the recalcitrance properties like crystallization of cellulose, lignin shield, and interlinking of lignocellulosic biomass is an ideal way to utilize the full-scale potential for biofuel production. This study exhibited three different pretreatment effects to enhance the digestibility of corn stover (CS) for methane production. In this context, steam explosion (SE) and thermal potassium hydroxide (KOH-60°C) treated CS produced the maximal methane yield of 217.5 and 243.1 mL/gvs, which were 40.0% and 56.4% more than untreated CS (155.4 mL/gvs), respectively. Copretreatment of thermal potassium hydroxide and steam explosion (CPTPS) treated CS was highly significant among all treatments and improved 88.46% (292.9 mL/gvs) methane yield compared with untreated CS. Besides, CPTPS also achieved the highest biodegradability up to 68.90%. Three kinetic models very well simulated dynamics of methane production yield. Moreover, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analyses declared the most effective changes in physicochemical properties after CPTPS pretreatment. Thus, CPTPS might be a promising approach to deconstructing the recalcitrance of lignocellulosic structure to improve the biodegradability for AD.

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

    Science.gov (United States)

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

    2009-08-01

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

  10. Improved biogas production and biodegradation of oilseed rape straw by using kitchen waste and duck droppings as co-substrates in two-phase anaerobic digestion.

    Science.gov (United States)

    Wang, Chuqiao; Hong, Feng; Lu, Yong; Li, Xianning; Liu, Hengming

    2017-01-01

    Oilseed rape straw (ORS) is a kind of biorefractory waste widely existing in the rural area of China, which is highly suitable to mix with kitchen waste (KW) and duck droppings (DD) in two-phase anaerobic digestion (AD). This research introduced the importance of KW and DD addition to improve the biogas production and biodegradation of ORS. A set of comparative experiments were conducted on two-phase mono- and co-digestion with organic load of 60 g VS/L. The total methane yield (TMY) and the biodegradation of ORS of co-digestions were obviously improving, and the synergistic effect found in the two-phase co-digestions. The optimum mixing ratio of ORS, KW and DD was 50:40:10, and the corresponding TMY and VS degradation rate of ORS were 374.5 mL/g VS and 49.7%, respectively. Addition of KW and DD maintained the pH within the optimal range for the hydrolyzing-acidification, improved the phase separation and buffering capacity of AD system.

  11. Improved biogas production and biodegradation of oilseed rape straw by using kitchen waste and duck droppings as co-substrates in two-phase anaerobic digestion

    Science.gov (United States)

    Wang, Chuqiao; Hong, Feng; Lu, Yong; Liu, Hengming

    2017-01-01

    Oilseed rape straw (ORS) is a kind of biorefractory waste widely existing in the rural area of China, which is highly suitable to mix with kitchen waste (KW) and duck droppings (DD) in two-phase anaerobic digestion (AD). This research introduced the importance of KW and DD addition to improve the biogas production and biodegradation of ORS. A set of comparative experiments were conducted on two-phase mono- and co-digestion with organic load of 60 g VS/L. The total methane yield (TMY) and the biodegradation of ORS of co-digestions were obviously improving, and the synergistic effect found in the two-phase co-digestions. The optimum mixing ratio of ORS, KW and DD was 50:40:10, and the corresponding TMY and VS degradation rate of ORS were 374.5 mL/g VS and 49.7%, respectively. Addition of KW and DD maintained the pH within the optimal range for the hydrolyzing-acidification, improved the phase separation and buffering capacity of AD system. PMID:28767709

  12. Improved anaerobic digestion of a thermally pretreated mixture of physicochemical sludge; broiler excreta and sugar cane wastes (SCW): Effect on organic matter solubilization, biodegradability and bioenergy production.

    Science.gov (United States)

    Nava-Valente, Noemí; Alvarado-Lassman, Alejandro; Nativitas-Sandoval, Liliana S; Mendez-Contreras, Juan M

    2016-01-01

    Thermal pretreatment effect of a mixture of organic wastes (physicochemical sludge, excreta of broiler chickens and sugarcane wastes (SCW)) in the solubilization and biodegradability organic matter as well as bioenergy production by anaerobic digestion was evaluated. Two different mixtures of physicochemical sludge, excreta of broiler chickens and SCW (70%, 15%, 15% and 60%, 20%, 20% of VS, respectively) were treated at different temperatures (80 °C, 85 °C and 90 °C) and contact time (30, 60 and 90 min). Results indicate that, organic matter solubilization degree increased from 1.14 to 6.56%; subsequently, in the anaerobic digestion process, an increase of 50% in the volatile solids removal and 10% in biogas production was observed, while, retention time decreased from 23 up to 9 days. The results obtained were similar to pilot-scale. In both experimental scales it showed that the synergy produced by the simultaneous anaerobic digestion of different substrates could increase bioenergy production up to 1.3 L bio g(-1) VS removed and 0.82 L CH4 g(-1) VS removed. The treatment conditions presented in this study allow for large residue quantities to be treated and large bioenergy quantities to be produced (10% higher than during conventional treatment) without increasing the anaerobic digester volume.

  13. Anaerobic biodegradation of lipids of the marine microalga Nannochloropsis salina

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Grossi, V.; Blokker, P.

    2001-01-01

    In order to determine the susceptibility to anaerobic biodegradation of the different lipid biomarkers present in a marine microalga containing algaenan, portions of one large batch of cultured Nannochloropsis salina (Eustigmatophyceae) were incubated in anoxic sediment slurries for various times. A

  14. Anaerobic biodegradation of spent sulphite liquor in a UASB reactor

    DEFF Research Database (Denmark)

    Jantsch, T.G.; Angelidaki, Irini; Schmidt, Jens Ejbye

    2002-01-01

    Anaerobic biodegradation of fermented spent sulphite liquor, SSL, which is produced during the manufacture of sulphite pulp, was investigated. SSL contains a high concentration of lignin products in addition to hemicellulose and has a very high COD load (173 g COD l1). Batch experiments with dilu......Anaerobic biodegradation of fermented spent sulphite liquor, SSL, which is produced during the manufacture of sulphite pulp, was investigated. SSL contains a high concentration of lignin products in addition to hemicellulose and has a very high COD load (173 g COD l1). Batch experiments...... such as incineration. Although the total COD reduction achieved is limited, bioenergy is produced and readily biodegradable matter is removed causing less load on post-treatment installations. 2002 Elsevier Science Ltd. All rights reserved....

  15. QSBR Study on the Anaerobic Biodegradation of Chlorophenols

    Institute of Scientific and Technical Information of China (English)

    YANG Da-Sen; DAI You-Zhi; LI Jian-Hua; ZHU Fei

    2006-01-01

    18 Physicochemical and quantum chemical parameters of 12 kinds of chlorophenols are calculated in this paper. QSBR (quantitative structure-biodegradability relationship) study is performed using simca statistical software by PLS regression analysis method on anaerobic biodegradation data (logKb), and the QSBR model is developed with favorable prediction. The model shows that the size and energy of the molecule are the dominant factors affecting the anaerobic biodegradation of chlorophenols. And the degradation rate constants (logKb) increase with the increase of core-core repulsion (CCR), average molecular polarizability (α), total surface area (TSA), heat of formation (HOF) and total energy (TE), while decrease with the increase of molecular connectivity index (1XV), relative molecular mass (Mw) and electronic energy (EE).

  16. Biodegradability of biodegradable/degradable plastic materials under aerobic and anaerobic conditions.

    Science.gov (United States)

    Mohee, R; Unmar, G D; Mudhoo, A; Khadoo, P

    2008-01-01

    A study was conducted on two types of plastic materials, Mater-Bi Novamont (MB) and Environmental Product Inc. (EPI), to assess their biodegradability under aerobic and anaerobic conditions. For aerobic conditions, organic fractions of municipal solid wastes were composted. For the anaerobic process, anaerobic inoculum from a wastewater treatment plant was used. Cellulose filter papers (CFP) were used as a positive control for both mediums. The composting process was monitored in terms of temperature, moisture and volatile solids and the biodegradation of the samples were monitored in terms of mass loss. Monitoring results showed a biodegradation of 27.1% on a dry basis for MB plastic within a period of 72 days of composting. Biodegradability under an anaerobic environment was monitored in terms of biogas production. A cumulative methane gas production of 245 ml was obtained for MB, which showed good degradation as compared to CFP (246.8 ml). However, EPI plastic showed a cumulative methane value of 7.6 ml for a period of 32 days, which was close to the blank (4.0 ml). The EPI plastic did not biodegrade under either condition. The cumulative carbon dioxide evolution after 32 days was as follows: CFP 4.406 cm3, MB 2.198 cm3 and EPI 1.328 cm3. The cumulative level of CO2 varying with time fitted sigmoid type curves with R2 values of 0.996, 0.996 and 0.995 for CFP, MB and EPI, respectively.

  17. [Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].

    Science.gov (United States)

    Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang

    2014-04-01

    Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

  18. Enhanced anaerobic biodegradability of real coal gasification wastewater with methanol addition.

    Science.gov (United States)

    Wang, Wei; Han, Hongjun; Yuan, Min; Li, Huiqiang

    2010-01-01

    Coal gasification effluent is a typical refractory industrial wastewater with a very poor anaerobic biodegradability due to its toxicity. Methanol was introduced to improve anaerobic biodegradability of real coal gasification wastewater, and the effect of methanol addition on the performance was investigated in a mesophilic upflow anaerobic sludge bed reactor with a hydraulic retention time of 24 hr. Experimental results indicated that anaerobic treatment of coal gasification wastewater was feasible with the addition of methanol. The corresponding maximum COD and phenol removal rates were 71% and 75%, respectively, with methanol concentration of 500 mg COD/L for a total organic loading rate of 3.5 kg COD/(m3 x day) and a phenol loading rate of 0.6 kg/(m3 x day). The phenol removal rate was not improved with a higher methanol concentration of 1000 mg COD/L. Substrate utilization rate (SUR) tests indicated that the SURs of phenol were 106, 132, and 83 mg phenol/(g VSS x day) at methanol concentrations of 250, 500, and 1000 mg COD/L, respectively, and only 45 mg phenol/(g VSS x day) in the control reactor. The presence of methanol could reduce the toxicity of coal gasification wastewater and increase the biodegradation of phenolic compounds.

  19. In situ biodegradation potential of aromatic hydrocarbons in anaerobic groundwaters

    Science.gov (United States)

    Acton, D. W.; Barker, J. F.

    1992-04-01

    Three types of experiments were conducted to assess the potential for enhancing the in situ biodegradation of nine aromatic hydrocarbons in anaerobic, leachate-impacted aquifers at North Bay, Ontario, and at Canada Forces Base Borden. Laboratory micrososms containing authentic aquifer material and groundwater from the North Bay site were amended with nitrate and glucose. No significant losses of aromatic hydrocarbons were observed compared to unamended controls, over a period of 187 days. A total of eight in situ biodegradation columns were installed in the North Bay and Borden aquifers. Remedial additions included electron acceptors (nitrate and sulphate) and primary substrates (acetate, lactate and yeast extract). Six aromatic hydrocarbons [toluene, ethylbenzene, m-xylene, o-xylene, cumene and 1,2,4-trimethylbenzene ( 1,2,4-TMB)] were completely degraded in at least one in situ column at the North Bay site. Only toluene was degraded in the Borden aquifer. In all cases, aromatic hydrocarbon attenuation was attributed to biodegradation by methanogenic and fermentative bacteria. No evidence of aromatic hydrocarbon degradation was observed in columns remediated with nitrate or primary substrates. A continuous forced gradient injection experiment with sulphate addition was conducted at the North Bay site over a period of 51 days. The concentration of six aromatic hydrocarbons was monitored over time in the injection wells and at piezometer fences located 2, 5 and 10 m downgradient. All compounds except toluene reached injection concentration between 14 and 26 days after pumping began, and showed some evidence of selective retardation. Toluene broke through at a subdued concentration (˜ 50% of injection levels), and eventually declined to undetectable levels on day 43. This attenuation was attributed to adaptation and biodegradation by anaerobic bacteria. The results from these experiments indicate that considerable anaerobic biodegradation of aromatic hydrocarbons in

  20. Anaerobic Biodegradation of Ethylene Glycol within Hydraulic Fracturing Fluid

    Science.gov (United States)

    Heyob, K. M.; Mouser, P. J.

    2014-12-01

    Ethylene glycol (EG) is a commonly used organic additive in hydraulic fracturing fluids used for shale gas recovery. Under aerobic conditions, this compound readily biodegrades to acetate and CO2 or is oxidized through the glycerate pathway. In the absence of oxygen, organisms within genera Desulfovibrio, Acetobacterium, and others can transform EG to acetaldehyde, a flammable and suspected carcinogenic compound. Acetaldehyde can then be enzymatically degraded to ethanol or acetate and CO2. However, little is known on how EG degrades in the presence of other organic additives, particularly under anaerobic conditions representative of deep groundwater aquifers. To better understand the fate and attenuation of glycols within hydraulic fracturing fluids we are assessing their biodegradation potential and pathways in batch anaerobic microcosm treatments. Crushed Berea sandstone was inoculated with groundwater and incubated with either EG or a synthetic fracturing fluid (SFF) containing EG formulations. We tracked changes in dissolved organic carbon (DOC), EG, and its transformation products over several months. Approximately 41% of bulk DOC in SFF is degraded within 21 days, with 58% DOC still remaining after 63 days. By comparison, this same SFF degrades by 70% within 25 days when inoculated with sediment-groundwater microbial communities, suggesting that bulk DOC degradation occurs at a slower rate and to a lesser extent with bedrock. Aerobic biodegradation of EG occurs rapidly (3-7 days); however anaerobic degradation of EG is much slower, requiring several weeks for substantial DOC loss to be observed. Ongoing experiments are tracking the degradation pathways of EG alone and in the presence of SFF, with preliminary data showing incomplete glycol transformation within the complex hydraulic fracturing fluid mixture. This research will help to elucidate rates, processes, and pathways for EG biodegradation and identify key microbial taxa involved in its degradation.

  1. Anaerobic biodegradation of linear alkylbenzene sulfonate (LAS) in upflow anaerobic sludge blanket (UASB) reactors.

    Science.gov (United States)

    Sanz, José L; Culubret, Elayne; de Ferrer, Juan; Moreno, Alfonso; Berna, José L

    2003-01-01

    The anaerobic biodegradation of Linear Alkylbenzene Sulfonate (LAS) was studied in Upflow Anaerobic Sludge Blanket Reactors (UASB). One reactor was fed with easily degradable substrates and commercial LAS solution during a period of 3 months (Reactor 1), meanwhile a second reactor was fed with a commercial LAS solution without co-substrate (Reactor 2) during 4 months. Both reactors were operated with an organic loading rate of 4-5 mg-LAS/l x day and a hydraulic retention time of one day. The LAS biodegradation was determined by full mass balance. LAS was analysed by HPLC in the liquid phase (influent and effluent streams of the reactors) as well as in the solid phase (granular sludge used as biomass). The results indicate a high level of removal (primary biodegradation: 64-85%). Biodegradation was higher in the absence of external co-substrates than in the presence of additional sources of carbon. This indicates that the surfactant can be partially used as carbon and energy source by anaerobic bacteria. Under the operating conditions used, inhibition of the methanogenic activity or any other negative effects on the biomass due to the presence of LAS were not observed. The methanogenic activity remained high and stable throughout the experiment.

  2. Anaerobic biodegradability of dairy wastewater pretreated with porcine pancreas lipase

    Directory of Open Access Journals (Sweden)

    Adriano Aguiar Mendes

    2010-12-01

    Full Text Available Lipids-rich wastewater was partial hydrolyzed with porcine pancreas lipase and the efficiency of the enzymatic pretreatment was verified by the comparative biodegradability tests (crude and treated wastewater. Alternatively, simultaneous run was carried out in which hydrolysis and digestion was performed in the same reactor. Wastewater from dairy industries and low cost lipase preparation at two concentrations (0.05 and 0.5% w.v-1 were used. All the samples pretreated with enzyme showed a positive effect on organic matter removal (Chemical Oxygen Demand-COD and formation of methane. The best results were obtained when hydrolysis and biodegradation were performed simultaneously, attaining high COD and color removal independent of the lipase concentration. The enzymatic treatment considerably improved the anaerobic operational conditions and the effluent quality (lower content of suspended solids and less turbidity. Thus, the use of enzymes such as lipase seemed to be a very promising alternative for treating the wastewaters having high fat and grease contents, such as those from the dairy industry.O presente trabalho teve como objetivo o pré-tratamento de efluente da indústria de laticínios na hidrólise de lipídeos, empregando lipase de fonte de células animais de baixo custo disponível comercialmente (pâncreas de porco na formação de gás metano por biodegradabilidade anaeróbia empregando diferentes concentrações de lipase (0,05 e 0,5 % w.v-1. A utilização de lipase no pré-tratamento do efluente acelerou a hidrólise de lipídeos e, conseqüentemente, auxiliou o tratamento biológico resultando na redução da matéria orgânica em termos de Demanda Química de Oxigênio (DQO, cor e sólidos em suspensão como lipídeos. Os melhores resultados em termos de remoção de DQO e cor foram obtidos quando a hidrólise e biodigestão foram realizadas simultaneamente, independente da concentração de lipase empregada. Estes resultados

  3. IMPACTS OF IRON, NUTRIENTS, AND MINERAL FINES ON ANAEROBIC BIODEGRADATION OF CANOLA OIL IN FRESHWATER SEDIMENTS

    Science.gov (United States)

    Factors affecting anaerobic biodegradation kinetics of canola oil in freshwater sediments were investigated. An optimum dose of ferric hydroxide (10.5 g Fe(III)·kg-1 sediment) was found to stimulate anaerobic biodegradation of canola oil (18.6 g oil kg-1). ...

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

    Science.gov (United States)

    Kristanto, Gabriel Andari; Asaloei, Huinny

    2017-03-01

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

  5. Anaerobic Biodegradation of Tetrachloroethylene with Acetic Acid as Cometabolism Substrate under Anaerobic Condition

    Institute of Scientific and Technical Information of China (English)

    LI Ye; LIU Fei; CHEN Honghan; SHI Jinhua; WANG Yufan

    2008-01-01

    A series of batch-type experiments with acetate acid as the primary substrate wereperformed using enrichment cultures developed from the anaerobic sludge to investigate the effect ofacetate acid on tetrachloroethylene (PCE) biodegradation. Experimental results indicated that acetateacid was an efficient electron donor in affecting the biotransformability of PCE. Trichloroethylene(TCE) was the primary dehalogenation product, and small amounts of dichloroethylenes (DCEs) werealso detected. No significant further DCEs degradation was detected. PCE degradation rate in theexperiment was 36.6 times faster than background rate in natural groundwater.

  6. Anaerobic biodegradability of phthalic acid isomers and related compounds.

    Science.gov (United States)

    Kleerebezem, R; Pol, L W; Lettinga, G

    1999-02-01

    All three phthalic acid isomers (ortho, meta and para benzene dicarboxylic acid) are produced in massive amounts, and used in the chemical industry as plasticizers or for the production of polyester. Wastestreams generated during the production of phthalate isomers generally contain high concentrations of aromatic acids. To study the potential biodegradability of these primarily anthropogenic compounds in anaerobic bioreactors, biodegradability studies were performed. Compounds tested were benzoate, ortho-phthalate, isophthalate, terephthalate, dimethyl phthalate, dimethyl terephthalate, para-toluate and para-xylene. Seed materials tested were two types of granular sludge and digested sewage sludge. It was found that all phthalate isomers and their corresponding dimethyl-esters, could be completely mineralized by all seed materials studied. Lag phases required for 50% degradation of these compounds, ranged from 17 to 156 days. The observed degradation curves could be explained by growth of an initially small amount of organisms in the inoculum with the specific ability to degrade one phthalate isomer. The observed order in the length of the lag phases for the phthalate isomers is: phthalate terephthalate terephthalate was found to be fermentation of the phthalate isomer. Para-toluate was degraded only by digested sewage sludge after a lag phase of 425 days. The observed degradation rates of this compound were very low. No mineralization of para-xylene was observed. In general, the differences in the lag phases between different seed materials were relatively small. These results indicate that the time needed for the start-up of anaerobic bioreactors treating wastewaters containing phthalic acid isomers, depends little on the microbial composition of the seed material applied, but may take several months.

  7. Integrated Anaerobic-Aerobic Biodegradation of Multiple Contaminants Including Chlorinated Ethylenes, Benzene, Toluene, and Dichloromethane.

    Science.gov (United States)

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

    Complete bioremediation of soils containing multiple volatile organic compounds (VOCs) remains a challenge. To explore the possibility of complete bioremediation through integrated anaerobic-aerobic biodegradation, laboratory feasibility tests followed by alternate anaerobic-aerobic and aerobic-anaerobic biodegradation tests were performed. Chlorinated ethylenes, including tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC), and dichloromethane (DCM) were used for anaerobic biodegradation, whereas benzene, toluene, and DCM were used for aerobic biodegradation tests. Microbial communities involved in the biodegradation tests were analyzed to characterize the major bacteria that may contribute to biodegradation. The results demonstrated that integrated anaerobic-aerobic biodegradation was capable of completely degrading the seven VOCs with initial concentration of each VOC less than 30 mg/L. Benzene and toluene were degraded within 8 days, and DCM was degraded within 20 to 27 days under aerobic conditions when initial oxygen concentrations in the headspaces of test bottles were set to 5.3% and 21.0%. Dehalococcoides sp., generally considered sensitive to oxygen, survived aerobic conditions for 28 days and was activated during the subsequent anaerobic biodegradation. However, degradation of cis-DCE was suppressed after oxygen exposure for more than 201 days, suggesting the loss of viability of Dehalococcoides sp., as they are the only known anaerobic bacteria that can completely biodegrade chlorinated ethylenes to ethylene. Anaerobic degradation of DCM following previous aerobic degradation was complete, and yet-unknown microbes may be involved in the process. The findings may provide a scientific and practical basis for the complete bioremediation of multiple contaminants in situ and a subject for further exploration.

  8. Comparative evaluation of anaerobic biodegradability of hydrocarbons and fatty derivatives currently used as drilling fluids.

    Science.gov (United States)

    Steber, J; Herold, C P; limia, J M

    1995-08-01

    The examination of a number of potential and currently used carrier fluids for invert emulsion drilling fluids in the ECETOC screening test revealed clear differences with respect to their easy anaerobic biodegradability. Fatty acid- and alcohol-based ester oils exhibited excellent anaerobic degradation to the gaseous final end products of the methanogenic degradation pathway, methane and carbon dioxide. Mineral oils, dialkyl ethers, alpha-olefins, polyalphaolefins, linear alkylbenzenes and an acetal-derivative were not or only slowly degraded. Although the poor degradation results obtained in the stringent ECETOC screening test may not be regarded as final proof of anaerobic recalcitrance, nevertheless, these results were found to be in line with the present understanding of the structural requirements for anaerobic biodegradability of chemicals. The validity of the conclusions drawn is corroborated by published results on the anaerobic biodegradation behaviour of ester oils, mineral oils and alkylbenzenes in marine sediments.

  9. Biodegradability and toxicity of sulphonate-based surfactants in aerobic and anaerobic aquatic environments.

    Science.gov (United States)

    García, M T; Campos, E; Marsal, A; Ribosa, I

    2009-02-01

    Four types of commonly used sulphonate-based surfactants (alkane sulphonates, alpha-olefin sulphonates, sulphosuccinates and methyl ester sulphonates) were tested for their aerobic and anaerobic biodegradability as well as for their toxicity to Daphnia magna and Photobacterium phosphoreum to assess the effect of the surfactant structure on those properties. Aerobic biodegradation was evaluated by means of the CO2 headspace test and anaerobic biodegradation was assessed by a method based on the ECETOC test. All the surfactants tested were readily biodegraded under aerobic conditions. No clear effect of the surfactant structures on the toxicity to the aquatic organisms tested was found. The most significant differences in the surfactants studied were observed in their behaviour under anaerobic conditions. Alkane sulphonates, alpha-olefin sulphonates and methyl ester sulphonates were not mineralized in lab anaerobic digesters despite the fact that the last one showed a certain degree of primary degradation. Nevertheless, these surfactants did not significantly inhibit methanogenic activity at concentrations up to 15 g surfactant/kg dry sludge, a concentration that is much higher than the expected concentrations of these surfactants in real anaerobic digesters. Sulphosuccinates showed a high level of primary biodegradation in anaerobic conditions. However, linear alkyl sulphosuccinates were completely mineralized whereas branched alkyl sulphosuccinates achieved percentages of ultimate biodegradation < or =50%.

  10. 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.

  11. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation

    Science.gov (United States)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  12. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation.

    Science.gov (United States)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  13. Biochemical methane potential and anaerobic biodegradability of non-herbaceous and herbaceous phytomass in biogas production

    DEFF Research Database (Denmark)

    Triolo, Jin Mi; Pedersen, Lene; Qu, Haiyan

    2012-01-01

    The suitability of municipal plant waste for anaerobic digestion was examined using 57 different herbaceous and non-herbaceous samples. Biochemical methane potential (BMP) and anaerobic biodegradability were related to the degree of lignification and crystallinity of cellulose. The BMP of herbace...

  14. 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...

  15. Kinetic study of the anaerobic biodegradation of alkyl polyglucosides and the influence of their structural parameters.

    Science.gov (United States)

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Jurado, Encarnación; Fernández-Serrano, Mercedes

    2016-05-01

    This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L(-1), are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment.

  16. Simulation of DEHP biodegradation and sorption during the anaerobic digestion of secondary sludge

    DEFF Research Database (Denmark)

    Fountoulakis, M.S.; Stamatelatou, K.; Batstone, Damien J.

    2006-01-01

    Di-ethylhexyl phthalate (DEHP) has commonly been found in the sludge of municipal wastewater treatment plants especially during anaerobic processing. It is slowly biodegradable under anaerobic conditions. Due to its high hydrophobicity, sorption-desorption processes can be rate-limiting for the c......Di-ethylhexyl phthalate (DEHP) has commonly been found in the sludge of municipal wastewater treatment plants especially during anaerobic processing. It is slowly biodegradable under anaerobic conditions. Due to its high hydrophobicity, sorption-desorption processes can be rate......-limiting for the compound biodegradation. In this study, the anaerobic biodegradation of DEHP was investigated through batch kinetic experiments and dynamic transitions of a continuous stirred tank reactor (CSTR) fed with secondary sludge contaminated with DEHP. A widely accepted model (ADM1) was used to fit the anaerobic...... digestion of secondary sludge and was properly extended to. account for DEHP removal, in which mass transfer processes are also involved. It was shown that DEHP removal was limited by the transfer of DEHP within the solid fraction. The criterion selected for the distinction of the two sites was whether...

  17. Kinetics and thermodynamics of biodegradation of hydrolyzed polyacrylamide under anaerobic and aerobic conditions.

    Science.gov (United States)

    Zhao, Lanmei; Bao, Mutai; Yan, Miao; Lu, Jinren

    2016-09-01

    Kinetics and thermodynamics of hydrolyzed polyacrylamide (HPAM) biodegradation in anaerobic and aerobic activated sludge biochemical treatment systems were explored to determine the maximum rate and feasibility of HPAM biodegradation. The optimal nutrient proportions for HPAM biodegradation were determined to be 0.08g·L(-1) C6H12O6, 1.00g·L(-1) NH4Cl, 0.36g·L(-1) NaH2PO4 and 3.00g·L(-1) K2HPO4 using response surface methodology (RSM). Based on the kinetics, the maximum HPAM biodegradation rates were 16.43385mg·L(-1)·d(-1) and 2.463mg·L(-1)·d(-1) in aerobic and anaerobic conditions, respectively. The activation energy (Ea) of the aerobic biodegradation was 48.9897kJ·mol(-1). Entropy changes (ΔS) of biochemical treatment system decreased from 216.21J·K(-1) to 2.39J·K(-1). Thermodynamic windows of opportunity for HPAM biodegradation were drawn. And it demonstrated HPAM was biodegraded into acetic acid and CO2 under laboratory conditions. Growth-process equations for functional bacteria anaerobically grown on polyacrylic acid were constructed and it confirmed electron equivalence between substrate and product.

  18. Anaerobic biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by a facultative anaerobe Pseudomonas sp. JP1.

    Science.gov (United States)

    Liang, Lei; Song, Xiaohui; Kong, Jing; Shen, Chenghui; Huang, Tongwang; Hu, Zhong

    2014-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are harmful persistent organic pollutants, while the high-molecular-weight (HMW) PAHs are even more detrimental to the environment and human health. However, microbial anaerobic degradation of HMW PAHs has rarely been reported. One facultative anaerobe Pseudomonas sp. JP1 was isolated from Shantou Bay, Shantou, China, which could degrade a variety of HMW PAHs. After 40 days cultivation with strain JP1, anaerobic biodegradation rate of benzo[a]pyrene (BaP), fluoranthene, and phenanthrene was 30, 47, and 5 %, respectively. Consumption of nitrate as the electron acceptor was confirmed by N-(1-naphthyl) ethylenediamine spectrophotometry. Supplementation of sodium sulfite, maltose, or glycine, and in a salinity of 0-20 ‰ significantly stimulated anaerobic degradation of BaP. Lastly, the anaerobic degradation metabolites of BaP by strain JP1 were investigated using GC/MS, and the degradation pathway was proposed. This study is helpful for further studies on the mechanism of anaerobic biodegradation of PAHs.

  19. Toxicity and biodegradability of olive mill wastewaters in batch anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Hamdi, M. (Centre de Biotechnologie, Sfax (Tunisia) Universite de Provence, Marseille (France))

    1992-11-01

    The anaerobic biodegradability and toxicity of olive mill wastewaters (OMW) were studied in batch anaerobic digestion experiments. Anaerobic digestion of OMW or the supernatant of its centrifugation, the methane production was achieved at up to 5-15% (V/V) dilution corresponding to only 5-20 g/L COD. The washed suspended solids of OMW were toxic at up to 80 g/L COD; however, the kinetic of biodegradability of OMW or the supernatant was faster than for suspended solids, which are constituted mealy of cellulose and lignin. The darkly colored polyphenols induce the problem of biodegradation of OMW, whereas the long chain fatty acids (LCFA), tannins and simple phenolic compounds are responsible for its toxicity for methanogenic bacteria. 26 refs., 4 figs., 1 tab.

  20. Anaerobic biodegradation of fluoranthene under methanogenic conditions in presence of surface-active compounds

    DEFF Research Database (Denmark)

    Fuchedzhieva, Nadezhda; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2008-01-01

    biodegradation was most likely as a result of the increased fluoranthene solubility. The results indicate that LAS can be considered as a promising agent for facilitation of the process of anaerobic polycyclic aromatic hydrocarbons (PAH) biodegradation under methanogenic conditions.......Bacillus cereus isolated from municipal wastewater treatment plant was used as a model strain to assess the efficiency of two anionic surfactants, a chemical surfactant and a biosurfactant during fluoranthene biodegradation under anaerobic methanogenic conditions. The surfactants selected...... for the study were linear alkyl benzene sulphonates (LAS) and rhamnolipid-biosurfactant complex from Pseudomonas sp. PS-17. Biodegradation of fluoranthene was monitored by GC/MS for a period up to 12th day. No change in the fluoranthene concentration was registered after 7th day. The presence of LAS enhanced...

  1. Long term studies on the anaerobic biodegradability of MTBE and other gasoline ethers

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2009-01-01

    to investigate the anaerobic biodegradability of MTBE and other gasoline ethers. Inoculums collected from various environments were used, along with different electron acceptors. Only one set of the batch experiments showed a 30-60% conversion of MTBE to tert-butyl alcohol under Fe(III)-reducing conditions...

  2. Anaerobic biodegradation of organochlorine pesticides in contaminated soil - Significance of temperature and availability

    NARCIS (Netherlands)

    Baczynski, T.H.; Pleissner, D.; Grotenhuis, J.T.C.

    2010-01-01

    Anaerobic biodegradation of the pesticides: ¿-hexachlorocyclohexane, methoxychlor, o,p'- and p,p'-DDT in field polluted soil was tested at 12, 22 and 30 °C, using methanogenic granular sludge as inoculum. The contaminants were removed quite effectively at all temperatures and their removal rates inc

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

    Directory of Open Access Journals (Sweden)

    Amirhossein Malakahmad

    2013-01-01

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

  4. The effect of cyclic anaerobic-aerobic conditions on biodegradation of azo dyes.

    Science.gov (United States)

    Yaşar, Semra; Cirik, Kevser; Cinar, Ozer

    2012-03-01

    The effect of cyclic anaerobic-aerobic conditions on the biodegradative capability of the mixed microbial culture for the azo dye Remazol Brilliant Violet 5R (RBV-5R) was investigated in the sequencing batch reactor (SBR) fed with a synthetic textile wastewater. The SBR had a 12-h cycle time with anaerobic-aerobic periods of 3/9, 6/6 and 9/3 h. General SBR performance was assessed by measurement of catabolic enzymes (catechol 2,3-dioxygenase, azo reductase), chemical oxygen demand (COD), color and amount of aromatic amines. In this study, under steady-state conditions, the anaerobic period of the cyclic SBR was found to allow the reductive decolorization of azo dye. Longer anaerobic periods resulted in higher color removal efficiencies, approximately 71% for the 3-h, 87% for 6-h and 92% for the 9-h duration. Total COD removal efficiencies were over 84% under each of the cyclic conditions and increased as the length of the anaerobic period was increased; however, the highest color removal rate was attained for the cycle with the shortest anaerobic period of 3 h. During the decolorization of RBV-5R, two sulfonated aromatic amines (benzene based and naphthalene based) were formed. Additionally, anaerobic azo reductase enzyme was found to be positively affected with the increasing duration of the anaerobic period; however; it was vice versa for the aerobic catechol 2,3-dioxygenase (C23DO) enzyme.

  5. Biodegradability of four phthalic acid esters under anaerobic condition assessed using natural sediment

    Institute of Scientific and Technical Information of China (English)

    Ruttapol Lertsirisopon; Satoshi Soda; Kazunari Sei; Michihiko Ike; Masanori Fujita

    2006-01-01

    Biodegradability of di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-ethylhexyl phthalate (DEHP), and di-isononyl phthalate (DINP) under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters(PAEs)were analyzed by a first-order kinetic model with a lag phase and ranked as DBP>BBP>>DEHP>DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of DINP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.

  6. Anaerobic biodegradation of soybean biodiesel and diesel blends under methanogenic conditions.

    Science.gov (United States)

    Wu, Shuyun; Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

    2015-12-15

    Biotransformation of soybean biodiesel and the inhibitory effect of petrodiesel were studied under methanogenic conditions. Biodiesel removal efficiency of more than 95% was achieved in a chemostat with influent biodiesel concentrations up to 2.45 g/L. The kinetics of anaerobic biodegradation of soybean biodiesel B100 (biodiesel only) with different petrodiesel loads was studied using biomass pre-acclimated to B100 and B80 (80% biodiesel and 20% petrodiesel). The results indicated that the biodiesel fraction of the blend could be effectively biodegraded, whereas petrodiesel was not biodegraded at all under methanogenic conditions. The presence of petrodiesel in blends with biodiesel had a greater inhibitory effect on the rate of biodegradation than the biodegradation efficiency (defined as the efficiency of methane production). Both the biodegradation rate coefficient and the methane production efficiency increased almost linearly with the increasing fraction of biodiesel. With the increasing fraction of petrodiesel, the biodegradation rate and efficiency were correlated with the concentration of soluble FAMEs in the water.

  7. 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

  8. TBA biodegradation in surface-water sediments under aerobic and anaerobic conditions

    Science.gov (United States)

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    2002-01-01

    The potential for [U-14C] TBA biodegradation was examined in laboratory microcosms under a range of terminal electron accepting conditions. TBA mineralization to CO2 was substantial in surface-water sediments under oxic, denitrifying, or Mn(IV)-reducing conditions and statistically significant but low under SO4-reducing conditions. Thus, anaerobic TBA biodegradation may be a significant natural attenuation mechanism for TBA in the environment, and stimulation of in situ TBA bioremediation by addition of suitable terminal electron acceptors may be feasible. No degradation of [U-14C] TBA was observed under methanogenic or Fe(III)-reducing conditions.

  9. Anaerobic biodegradability of dairy wastewater pretreated with porcine pancreas lipase

    OpenAIRE

    2010-01-01

    Lipids-rich wastewater was partial hydrolyzed with porcine pancreas lipase and the efficiency of the enzymatic pretreatment was verified by the comparative biodegradability tests (crude and treated wastewater). Alternatively, simultaneous run was carried out in which hydrolysis and digestion was performed in the same reactor. Wastewater from dairy industries and low cost lipase preparation at two concentrations (0.05 and 0.5% w.v-1) were used. All the samples pretreated with enzyme showed a p...

  10. ANAEROBIC BIODEGRADATION OF ORGANIC COMPOUNDS IN MICROBIAL FUEL CELLS

    Directory of Open Access Journals (Sweden)

    Samkov A. A.

    2014-09-01

    Full Text Available МF-4SК membrane-based microbial fuel cell (MFC was used for an anaerobic utilization of organic com-pounds of various liquid wastes. During incubation in short circuit mode, decreasing of the COD value on range 30-87 % depending on the type of wastes was detected. The dependence of the microbial fuel cell output power on the value of the external load was determined by a number of structural characteristics of MFC

  11. Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry

    Science.gov (United States)

    Dors, Gisanara; Mendes, Adriano A.; Pereira, Ernandes B.; de Castro, Heizir F.; Furigo, Agenor

    2013-03-01

    Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry with porcine pancreatic lipase at different concentrations (from 1.0 to 3.0 g L-1) were performed. The efficiency of the enzymatic pretreatment was measured by the Chemical Oxygen Demand (COD) removal and formation of methane. All samples pretreated with lipase showed a positive effect on the COD removal and formation of methane. After 30 days of anaerobic biodegradation the methane production varied from 569 ± 95 to 1,101 ± 10 mL for crude wastewater and pretreated at 3.0 g L-1 enzyme, respectively. COD removal of wastewater supplemented at different enzyme concentrations was found to be threefold higher than crude wastewater. The use of lipases seems to be a promising alternative for treating lipid-rich wastewaters such as those from the poultry industry.

  12. A mesocasm study of enhanced anaerobic biodegradation of petroleum hydrocarbons in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.; Guigard, S.; Biggar, K. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering; Foght, J.; Semple, K. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences

    2005-07-01

    Under certain conditions, Natural Attenuation (NA) processes can act to reduce the mass, toxicity, mobility, volume or concentrations of contaminants in soil or groundwater within a reasonable time frame. NA processes are considered to be a more cost-effective remediation approach than engineered processes. However, the rates of biodegradation in cold regions are slower and occasionally the processes are nutrient or Terminal Electron Acceptor (TEA) limited. These limitations may make NA less viable due to slower rates of biological activity. This paper discusses the results of a mesocasm study conducted in laboratory-controlled conditions to investigate the TEA and nutrient enhanced anaerobic biodegradation of petroleum hydrocarbons in groundwater from two sites in Alberta. Target compounds for the study were BTEX and the CCME F1 fraction. Samples taken from the site were used to set up 11 L mesocasms with a water to soil ratio of 10:1 under anaerobic conditions. The samples were amended with nitrate and sulfate and then incubated. Sub-sampling was carried out once a month to monitor substrate consumption, TEA depletion and evolution of biogenic gases. Microbial enumeration and metabolite analysis were also done. No final conclusions could be drawn from the study, which had only been carried out for 6 months at the time that this paper was written. However, results to date have indicated that the method of mesocasms and sub-sampling are applicable to anaerobic biodegradation studies. In addition, nutrient supplementation appears to enhance nitrate and sulfate reduction. However, the TEA depletion was greater than expected and could not be explained by the substrate consumption. Results also indicated that the groundwater from site 1 was sulfate-limited, suggesting that sulfate amendment could enhance anaerobic biodegradation of CCME F1 petroleum hydrocarbons. Data from the ongoing study may provide additional insight to clarify processes in the mesocasms. 9 refs

  13. Biodegradation of phenanthrene in an anaerobic batch reactor: growth kinetics

    Directory of Open Access Journals (Sweden)

    H.S. Nasrollahzadeh

    2010-07-01

    Full Text Available The purpose of the present research was to demonstrate the ability of mixed consortia of microorganisms to degrade high concentrations of phenanthrene (PHE as the sole carbon source. Batch experiments were carried out by the induction of mineral salt medium containing PHE to the seed culture and monitoring PHE biodegradation. The microbial propagation was conducted using PHE concentrations in the range of 20 to 100 mg/l. The microbial growth on PHE was defined based on Monod and modified Logistic rate models. The kinetic studies revealed that maximum specific growth rates (μm for PHE concentrations of 20, 50 and 100 mg/l were 0.12, 0.23 and 0.035 h-1, respectively. The doubling times for microbial population in PHE concentrations of 20, 50 and 100 mg/l were 13, 15 and 17.5 h, respectively. Also, maximum cell dry weight (xm of 54.23 mg/l was achieved, while the inhibition coefficient was 0.023 h-1. It was observed that the experimental data were well represented by the proposed models. It was also found that the biodegradation of PHE was successfully performed by the isolated strains.

  14. Enantioselective reductive transformation of climbazole: A concept towards quantitative biodegradation assessment in anaerobic biological treatment processes.

    Science.gov (United States)

    Brienza, Monica; Chiron, Serge

    2017-06-01

    An efficient chiral method-based using liquid chromatography-high resolution-mass spectrometry analytical method has been validated for the determination of climbazole (CBZ) enantiomers in wastewater and sludge with quantification limits below the 1 ng/L and 2 ng/g range, respectively. On the basis of this newly developed analytical method, the stereochemistry of CBZ was investigated over time in sludge biotic and sterile batch experiments under anoxic dark and light conditions and during wastewater biological treatment by subsurface flow constructed wetlands. CBZ stereoselective degradation was exclusively observed under biotic conditions, confirming the specificity of enantiomeric fraction variations to biodegradation processes. Abiotic CBZ enantiomerization was insignificant at circumneutral pH and CBZ was always biotransformed into CBZ-alcohol due to the specific and enantioselective reduction of the ketone function of CBZ into a secondary alcohol function. This transformation was almost quantitative and biodegradation gave good first order kinetic fit for both enantiomers. The possibility to apply the Rayleigh equation to enantioselective CBZ biodegradation processes was investigated. The results of enantiomeric enrichment allowed for a quantitative assessment of in situ biodegradation processes due to a good fit (R(2) > 0.96) of the anoxic/anaerobic CBZ biodegradation to the Rayleigh dependency in all the biotic microcosms and was also applied in subsurface flow constructed wetlands. This work extended the concept of applying the Rayleigh equation towards quantitative biodegradation assessment of organic contaminants to enantioselective processes operating under anoxic/anaerobic conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO3.

    Science.gov (United States)

    Li, Chun-Hua; Wong, Yuk-Shan; Wang, Hong-Yuan; Tam, Nora Fung-Yee

    2015-04-01

    Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of NaHCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7-13 days for 3-ring PAHs and 11-24 days for 4-ring PAHs. While NaHCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased. One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding NaHCO3.

  16. Evaluation of the aerobic and anaerobic biodegradability of the antibiotic norfloxacin.

    Science.gov (United States)

    de Souza Santos, Lucilaine Valéria; Teixeira, Danusa Campos; Jacob, Raquel Sampaio; Amaral, Míriam Cristina Santos do; Lange, Liséte Celina

    2014-01-01

    The purpose of studying the biodegradability of pharmaceutical compounds is to evaluate their behaviors in relation to the treatment processes generally used in domestic and industrial wastewater treatment plants. The antibiotic norfloxacin was found to be a recalcitrant compound. The studies conducted showed norfloxacin removal rates of 12% and 18% when biomasses from treatments with activated sludge and anaerobic biodigesters, respectively, were used without acclimatization. This suggests that anaerobic digestion shows better performance for norfloxacin removal. Ecotoxicological tests, using the luminescent marine bacteria Aliivibrio fischeri as the test organism, show that anaerobic digestion could eliminate the toxicity of the antibiotic norfloxacin, even though total degradation of the drug was not observed. The release of norfloxacin during cell lysis suggests the importance of controlling this phenomenon in biological treatment systems that handle wastewater contaminated with norfloxacin, thus preventing the return of this drug to the environment.

  17. Inhibition of biogas production and biodegradability by substituted phenolic compounds in anaerobic sludge.

    Science.gov (United States)

    Hernandez, J E; Edyvean, R G J

    2008-12-15

    Phenolic compounds are abundant in nature and organic wastes. This biomass may be utilised in biogas generation. Phenolics can inhibit the degradation of readily biodegradable organic fractions and their own biodegradation. In this work, assays were carried out under anaerobic conditions to study the inhibition of both gas production and biodegradability due to seven phenolic compounds and to study their adsorption onto sludge and autoxidation in the aqueous medium. Fifty percent inhibition was in the range of 120 to 594 mg of compound/g VSS. An initial enhancement followed by an inhibition of biogas formation was found. The inhibition by the phenolic compounds was found to be influenced by autoxidation, apolarity, type, size and number of substitutions. Biogas production is influenced by concentration rather than any pH change. The concentration of the phenolic compound was partially biomethanized and the degradation of gallic and caffeic acids by this process is reported here for the first time. The maximum total biodegradation of any phenolic compound was 63.85+/-2.73%, and remaining non-biodegradable fraction was autoxidized and adsorbed onto the sludge matrix. Inhibition of methanization and partial inhibition of background gas was found at concentrations between 800 and 1600 mg/L organic carbon.

  18. 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

  19. Kinetics of the biodegradation of green table olive wastewaters by aerobic and anaerobic treatments

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, J. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: jbelther@unex.es; Gonzalez, T.; Garcia, J. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)

    2008-06-15

    The biodegradation of the organic pollutant matter present in green table olive wastewater (GTOW) is studied in batch reactors by an aerobic biodegradation and by an anaerobic digestion. In the aerobic biodegradation, the evolution of the substrate (in terms of chemical and biochemical oxygen demand), biomass, and total polyphenolic compounds present in the wastewater are followed during the process, and a kinetic study is performed using Contois' model, which when applied to the experimental results provides the kinetic parameter of this model, resulting in a modified Contois' equation (q = 3.3S/(0.31S{sub 0}X + X), gCOD/gVSS d{sup -1}). Other kinetic parameters were determined: the cellular yield coefficient (Y{sub X/S} = 5.7 x 10{sup -2} gVSS/gCOD) and the kinetic constant of cellular death phase (k{sub d} = 0.16 d{sup -1}). Similarly, in the anaerobic digestion, the evolution of the substrate digested and the methane produced are followed, and the kinetic study is conducted using a modified Monod model combined with the Levenspiel model, due to the presence of inhibition effects. This model leads to the determination of the kinetic parameters: kinetic constant when no inhibitory substance is present (k{sub M0} = 8.4 x 10{sup -2} h{sup -1}), critical substrate concentration of inhibition (TP* = 0.34 g/L) and inhibitory parameter (n = 2.25)

  20. Kinetics of the biodegradation of green table olive wastewaters by aerobic and anaerobic treatments.

    Science.gov (United States)

    Beltran, J; Gonzalez, T; Garcia, J

    2008-06-15

    The biodegradation of the organic pollutant matter present in green table olive wastewater (GTOW) is studied in batch reactors by an aerobic biodegradation and by an anaerobic digestion. In the aerobic biodegradation, the evolution of the substrate (in terms of chemical and biochemical oxygen demand), biomass, and total polyphenolic compounds present in the wastewater are followed during the process, and a kinetic study is performed using Contois' model, which when applied to the experimental results provides the kinetic parameter of this model, resulting in a modified Contois' equation (q=3.3S/(0.31S(0)X+X), gCOD/gVSS d(-1)). Other kinetic parameters were determined: the cellular yield coefficient (YX/S=5.7x10(-2) gVSS/gCOD) and the kinetic constant of cellular death phase (kd=0.16 d(-1)). Similarly, in the anaerobic digestion, the evolution of the substrate digested and the methane produced are followed, and the kinetic study is conducted using a modified Monod model combined with the Levenspiel model, due to the presence of inhibition effects. This model leads to the determination of the kinetic parameters: kinetic constant when no inhibitory substance is present (kM0=8.4x10(-2) h(-1)), critical substrate concentration of inhibition (TP*=0.34 g/L) and inhibitory parameter (n=2.25).

  1. Screening tests for assessing the anaerobic biodegradation of pollutant chemicals in subsurface environments

    Science.gov (United States)

    Suflita, Joseph M.; Concannon, Frank

    1995-01-01

    Screening methods were developed to assess the susceptibility of ground water contaminants to anaerobic biodegradation. One method was an extrapolation of a procedure previously used to measure biodegradation activity in dilute sewage sludge. Aquifer solids and ground water with no additional nutritive media were incubated anaerobically in 160-ml serum bottles containing 250 mg·l−1 carbon of the substrate of interest. This method relied on the detection of gas pressure or methane production in substrateamended microcosms relative to background controls. Other screening procedures involved the consumption of stoichiometrically required amounts of sulfate or nitrate from the same type of incubations. Close agreement was obtained between the measured and calculated amounts of substrate bioconversion based on the measured biogas pressure in methanogenic microcosms. Storage of the microcosms for up to 6 months did not adversely influence the onset or rate of benzoic acid mineralization. The lower detection limits of the methanogenic assay were found to be a function of the size of the microcosm headspace, the mean oxidation state of the substrate carbon, and the method used to correct for background temperature fluctuations. Using these simple screening procedures, biodegradation information of regulatory interest could be generated, including, (i) the length of the adaptation period, (ii) the rate of substrate decay and (iii) the completeness of the bioconversion.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  3. Biodegradation of linear alkylbenzene sulfonate in commercial laundry wastewater by an anaerobic fluidized bed reactor.

    Science.gov (United States)

    Braga, Juliana K; Motteran, Fabrício; Macedo, Thaís Z; Sakamoto, Isabel K; Delforno, Tiago P; Okada, Dagoberto Y; Silva, Edson L; Varesche, Maria Bernadete A

    2015-01-01

    The biodegradation of linear alkylbenzene sulfonate (LAS) from commercial laundry wastewater was evaluated in an anaerobic fluidized bed reactor (FBR) fed with synthetic substrate (598 mg L(-1) to 723 mg L(-1) of organic matter) supplemented with 9.5±3.1 mg L(-1) to 27.9±9.6 mg L(-1) of LAS. The average chemical oxygen demand (COD) removal efficiency was 89% and the biodegradation of LAS was 57% during the 489 days of anaerobic FBR. Higher levels of volatile fatty acids (VFA) were observed in the effluent at the stage with the best LAS removal performance. Increasing the surfactant concentration did not increase the VFA production in the effluent. The predominant VFAs after the addition of LAS were as follows: isovaleric acid and valeric acid, followed by propionic acid, caproic acid and formic acid. The similarities of 64% and 45% to Archaea and Bacteria domains were observed in the samples taken in the operating period of anaerobic FBR fed with 23.6±10 mg L(-1) and 27.9±10 mg L(-1) of LAS. During the operation stages in the reactor, Gemmatimonas, Desulfobulbus and Zoogloea were determined as the most abundant genera related to surfactant degradation using 454-Pyrosequencing.

  4. Primary biodegradation of veterinary antibiotics in aerobic and anaerobic surface water simulation systems

    DEFF Research Database (Denmark)

    Ingerslev, Flemming; Toräng, Lars; Loke, M.-L.

    2001-01-01

    of the study was to provide rate data for primary biodegradation in the scenario where antibiotics pollute surface waters as a result of run-off from arable land. The source of antibiotics may be application of manure as fertilizer or excreta of grazing animals. Assuming first-order degradation kinetics......The primary aerobic and anaerobic biodegradability at intermediate concentrations (50-5000 mug/l) of the antibiotics olaquindox (OLA), metronidazole (MET), tylosin (TYL) and oxytetracycline (OTC) was studied in a simple shake flask system simulating the conditions in surface waters. The purpose......, ranges of half-lifes for aerobic degradation of the four antibiotics studied were 4-8 days (OLA), 9.5-40 days (TYL), 14-104 days (MET) and 42-46 days (OTC). OLA and OTC were degraded with no initial lag phase whereas lag phases from 2 to 34 days (MET) and 31 to 40 days (TYL) were observed for other...

  5. Anaerobic nonylphenol ethoxylate degradation coupled to nitrate reduction in a modified biodegradability batch test.

    Science.gov (United States)

    Luppi, Lorena I; Hardmeier, Ivo; Babay, Paola A; Itria, Raúl F; Erijman, Leonardo

    2007-08-01

    The aim of this work was to elucidate the role of nitrate as a terminal electron acceptor on the biodegradation of NPEO. We have characterized the products of NPEO degradation by mixed microbial communities in anaerobic batch tests by means of HPLC, (1)H NMR and GC-MS. Anaerobic degradation of NPEO was strictly dependent on the presence of nitrate. Within seven days of anoxic incubation, NP2EO appeared as the major degradation product. After 21 days, NP was the main species detected, and was not degraded further even after 35 days. Nitrate concentration decreased in parallel with NPEO de-ethoxylation. A transient accumulation of nitrite was observed within the time period in which NP formation reached its maximum production. The observed generation of nonylphenol coupled to nitrate reduction suggests that the microbial consortium possessed an alternate pathway for the degradation of NPEO, which was not accessible under aerobic conditions.

  6. Problems Caused by Microbes and Treatment Strategies Anaerobic Hydrocarbon Biodegradation and Biocorrosion: A Case Study

    Science.gov (United States)

    Suflita, Joseph M.; Duncan, Kathleen E.

    The anaerobic biodegradation of petroleum hydrocarbons is important for the intrinsic remediation of spilt fuels (Gieg and Suflita, 2005), for the conversion of hydrocarbons to clean burning natural gas (Gieg et al., 2008; Jones et al., 2008) and for the fundamental cycling of carbon on the planet (Caldwell et al., 2008). However, the same process has also been implicated in a host of difficult problems including reservoir souring (Jack and Westlake, 1995), oil viscosity alteration (Head et al., 2003), compromised equipment performance and microbiologically influenced corrosion (Duncan et al., 2009). Herein, we will focus on the role of anaerobic microbial communities in catalysing biocorrosion activities in oilfield facilities. Biocorrosion is a costly problem that remains relatively poorly understood. Understanding of the underlying mechanisms requires reliable information on the carbon and energy sources supporting biofilm microorganisms capable of catalysing such activities.

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

    Science.gov (United States)

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

    2009-09-01

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

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

    Science.gov (United States)

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

    2004-01-01

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

  9. Azoarcus sp. CIB, an anaerobic biodegrader of aromatic compounds shows an endophytic lifestyle.

    Directory of Open Access Journals (Sweden)

    Helga Fernández

    Full Text Available BACKGROUND: Endophytic bacteria that have plant growth promoting traits are of great interest in green biotechnology. The previous thought that the Azoarcus genus comprises bacteria that fit into one of two major eco-physiological groups, either free-living anaerobic biodegraders of aromatic compounds or obligate endophytes unable to degrade aromatics under anaerobic conditions, is revisited here. METHODOLOGY/PRINCIPAL FINDINGS: Light, confocal and electron microscopy reveal that Azoarcus sp. CIB, a facultative anaerobe β-proteobacterium able to degrade aromatic hydrocarbons under anoxic conditions, is also able to colonize the intercellular spaces of the rice roots. In addition, the strain CIB displays plant growth promoting traits such nitrogen fixation, uptake of insoluble phosphorus and production of indoleacetic acid. Therefore, this work demonstrates by the first time that a free-living bacterium able to degrade aromatic compounds under aerobic and anoxic conditions can share also an endophytic lifestyle. The phylogenetic analyses based on the 16S rDNA and nifH genes confirmed that obligate endophytes of the Azoarcus genus and facultative endophytes, such as Azoarcus sp. CIB, locate into different evolutionary branches. CONCLUSIONS/SIGNIFICANCE: This is the first report of a bacterium, Azoarcus sp. CIB, able to degrade anaerobically a significant number of aromatic compounds, some of them of great environmental concern, and to colonize the rice as a facultative endophyte. Thus, Azoarcus sp. CIB becomes a suitable candidate for a more sustainable agricultural practice and phytoremediation technology.

  10. A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The high strength easily biodegradable pollutants(represented by CODE) are strong inhibitors of terephthalic acid(TA) anaerobic biodegradation. At the same time, TA can inhibiteasily biodegradable pollutants removal under anaerobic conditionsto a limited extent. This mutual inhibition could happen and causea low removal efficiency of both TA and CODE, when the effluentfrom TA workshops containing TA and easily biodegradable pollutantsare treated by a single anaerobic reactor system. Based upon thetreatment kinetics analysis of both TA degradation and CODEremoval, a two-stage up-flow anaerobic sludge blanket and up-flowfixed film reactor(UASB-UAFF) system for dealing with this kind ofwastewater was developed and run successfully at laboratory scale.An UASB reactor with the methanogenic consortium as the first stageremoves the easily biodegradable pollutants(CODE). An UAFF reactor as the second stage is mainly in charge of TA degradation. At aHRT 18.5h, the CODE and TA removal rate of the system reached 89.2% and 71.6%, respectively.

  11. Benzene biodegradation using an anaerobic column coupled to Mn(IV) reduction

    Energy Technology Data Exchange (ETDEWEB)

    Villatoro-Monzon, W.R.; Velasquez-Mejia, E.K.; Morales-Ibarria, M.G.; Razo-Flores, E. [Instituto Mexicano del Petroleo (Mexico). Programo de Biotenologia del Petroleo

    2004-07-01

    Benzene, toluene, and o, m, p-xylene compounds make up a large proportion of gasoline. Due to spills and leaks from underground tanks, these compounds frequently contaminate groundwater and sediment. In particular the high solubility of benzene makes it very mobile and an extra danger to groundwater. Moreover, there are strong links between benzene and cancer and thus benzene is considered a serious pollutant. Contaminated sites usually become anaerobic due to microbe action. In this study, benzene biodegradation was done in a glass column inoculated with anaerobic Rhine River sediment and using Mn(IV) as the final electron acceptor. Under steady state operation, benzene biodegradation efficiency was as high as 95 per cent. Carbon dioxide and Mn(II) recovery rates were 81 and 77 per cent respectively. Reactor sediment was withdrawn on day 104 and subject to DGGE profiling. This sediment showed different band patterns than the original sediment that was not exposed to benzene. The authors conclude that the species associated with the degradation of benzene are of the genus Propionibacterium and Actinomyces. 17 refs., 2 figs.

  12. Biodegradation kinetics of selected brominated flame retardants in aerobic and anaerobic soil

    Energy Technology Data Exchange (ETDEWEB)

    Nyholm, Jenny Rattfelt, E-mail: jenny.rattfelt@chem.umu.s [Department of Chemistry, Umea University, SE-901 87 Umea (Sweden); Lundberg, Charlott; Andersson, Patrik L. [Department of Chemistry, Umea University, SE-901 87 Umea (Sweden)

    2010-06-15

    The purpose of the present study was to investigate the biodegradation kinetics in aerobic and anaerobic soil of the following brominated flame retardants: 2,4,4'-tribromodiphenyl ether (BDE 28), decabromodiphenyl ether (BDE 209), tetrabromobisphenol A (TBBPA), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), 2,4,6-tribromophenol (246BrPh), and hexabromobenzene (HxBrBz). For comparison, the biodegradation of the chlorinated compounds 2,4,4'-trichlorodiphenyl ether (CDE 28), 2,4,6-trichlorophenol (246ClPh), hexachlorobenzene (HxClBz), and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) was also assessed. In aerobic soil, BDE 209 showed no significant degradation during the test period, but concentrations of the other BFRs declined, with half-lives decreasing in the following order: BDE 28 > TBBPA > TBECH > HxBrBz > 246BrPh. Declines in almost the same order were observed in anaerobic soil: BDE 28, BDE 209 > TBBPA > HxBrBz > TBECH >246BrPh. - Intra- and extrapolated half-lives in soil of tested brominated flame retardants ranged from 7 days for 2,4,6-tribromorophenol to >400 days for decabromodiphenyl ether.

  13. 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)

  14. Biodegradation of pentaerythritol tetranitrate (PETN) by anaerobic consortia from a contaminated site.

    Science.gov (United States)

    Zhuang, Li; Gui, Lai; Gillham, Robert W

    2012-10-01

    This study examined the role of denitrifying and sulfate-reducing bacteria in biodegradation of pentaerythritol tetranitrate (PETN). Microbial inocula were obtained from a PETN-contaminated soil. PETN degradation was evaluated using nitrate and/or sulfate as electron acceptors and acetate as a carbon source. Results showed that under different electron acceptor conditions tested, PETN was sequentially reduced to pentaerythritol via the intermediary formation of tri-, di- and mononitrate pentaerythritol (PETriN, PEDN and PEMN). The addition of nitrate enhanced the degradation rate of PETN by stimulating greater microbial activity and growth of nitrite reducing bacteria that were responsible for degrading PETN. However, a high concentration of nitrite (350mgL(-1)) accumulated from nitrate reduction, consequently caused self-inhibition and temporarily delayed PETN biodegradation. In contrast, PETN degraded at very similar rates in the presence and absence of sulfate, while PETN inhibited sulfate reduction. It is apparent that denitrifying bacteria possessing nitrite reductase were capable of using PETN and its intermediates as terminal electron acceptors in a preferential utilization sequence of PETN, PETriN, PEDN and PEMN, while sulfate-reducing bacteria were not involved in PETN biodegradation. This study demonstrated that under anaerobic conditions and with sufficient carbon source, PETN can be effectively biotransformed by indigenous denitrifying bacteria, providing a viable means of treatment for PETN-containing wastewaters and PETN-contaminated soils. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Anaerobic digestion of seven different sewage sludges: a biodegradability and modelling study.

    Science.gov (United States)

    Astals, S; Esteban-Gutiérrez, M; Fernández-Arévalo, T; Aymerich, E; García-Heras, J L; Mata-Alvarez, J

    2013-10-15

    Seven mixed sewage sludges from different wastewater treatment plants, which have an anaerobic digester in operation, were evaluated in order to clarify the literature uncertainty with regard to the sewage sludge characterisation and biodegradability. Moreover, a methodology is provided to determine the Anaerobic Digestion Model No. 1 parameters, coefficients and initial state variables as well as a discussion about the accuracy of the first order solubilisation constant, which was obtained through biomethane potential test. The results of the biomethane potential tests showed ultimate methane potentials from 188 to 214 mL CH4 g(-1) CODfed, COD removals between 58 and 65% and two homogeneous groups for the first order solubilisation constant: (i) the lowest rate group from 0.23 to 0.35 day(-1) and (ii) the highest rate group from 0.27 to 0.43 day(-1). However, no statistically significant relationship between the ultimate methane potential or the disintegration constant and the sewage sludge characterisation was found. Next, a methodology based on the sludge characterisation before and after the biomethane potential test was developed to calculate the biodegradable fraction, the composite concentration and stoichiometric coefficients and the soluble COD of the sewage sludge; required parameters for the implementation of the Anaerobic Digestion Model No. 1. The comparison of the experimental and the simulation results proved the consistency of the developed methodology. Nevertheless, an underestimation of the first order solubilisation constant was detected when the experimental results were simulated with the solubilisation constant obtained from the linear regression experimental data fitting. The latter phenomenon could be related to the accumulation of intermediary compounds during the biomethane potential assay.

  16. Anaerobic biodegradability of Category 2 animal by-products: methane potential and inoculum source.

    Science.gov (United States)

    Pozdniakova, Tatiana A; Costa, José C; Santos, Ricardo J; Alves, M M; Boaventura, Rui A R

    2012-11-01

    Category 2 animal by-products that need to be sterilized with steam pressure according Regulation (EC) 1774/2002 are studied. In this work, 2 sets of experiments were performed in mesophilic conditions: (i) biomethane potential determination testing 0.5%, 2.0% and 5.0% total solids (TS), using sludge from the anaerobic digester of a wastewater treatment plant as inoculum; (ii) biodegradability tests at a constant TS concentration of 2.0% and different inoculum sources (digested sludge from a wastewater treatment plant; granular sludge from an upflow anaerobic sludge blanket reactor; leachate from a municipal solid waste landfill; and sludge from the slaughterhouse wastewater treatment anaerobic lagoon) to select the more adapted inoculum to the substrate in study. The higher specific methane production was of 317 mL CH(4)g(-1) VS(substrate) for 2.0% TS. The digested sludge from the wastewater treatment plant led to the lowest lag-phase period and higher methane potential rate. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Simulation of aerobic and anaerobic biodegradation processes at a crude oil spill site

    Science.gov (United States)

    Essaid, Hedeff I.; Bekins, Barbara A.; Godsy, E. Michael; Warren, Ean; Baedecker, Mary Jo; Cozzarelli, Isabelle M.

    1995-01-01

    A two-dimensional, multispecies reactive solute transport model with sequential aerobic and anaerobic degradation processes was developed and tested. The model was used to study the field-scale solute transport and degradation processes at the Bemidji, Minnesota, crude oil spill site. The simulations included the biodegradation of volatile and nonvolatile fractions of dissolved organic carbon by aerobic processes, manganese and iron reduction, and methanogenesis. Model parameter estimates were constrained by published Monod kinetic parameters, theoretical yield estimates, and field biomass measurements. Despite the considerable uncertainty in the model parameter estimates, results of simulations reproduced the general features of the observed groundwater plume and the measured bacterial concentrations. In the simulation, 46% of the total dissolved organic carbon (TDOC) introduced into the aquifer was degraded. Aerobic degradation accounted for 40% of the TDOC degraded. Anaerobic processes accounted for the remaining 60% of degradation of TDOC: 5% by Mn reduction, 19% by Fe reduction, and 36% by methanogenesis. Thus anaerobic processes account for more than half of the removal of DOC at this site.

  18. Formation of metabolites during biodegradation of linear alkylbenzene sulfonate in an upflow anaerobic sludge bed reactor under thermophilic conditions

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Ahring, Birgitte Kiær

    2002-01-01

    Biodegradation of linear alkylbenzene sulfonate (LAS) was shown in an upflow anaerobic sludge blanket reactor under thermophilic conditions. The reactor was inoculated with granular biomass and fed with a synthetic medium and 3 mumol/L of a mixture of LAS with alkylchain length of 10 to 13 carbon...

  19. PAH fate during the anaerobic digestion of contaminated sludge: Do bioavailability and/or cometabolism limit their biodegradation?

    Science.gov (United States)

    Barret, M; Carrère, H; Delgadillo, L; Patureau, D

    2010-07-01

    The anaerobic removal of 13 Polycyclic Aromatic Hydrocarbons (PAHs) was measured in five continuous anaerobic digestors with different feed sludge, in which abiotic losses were neglected. These feeds were chosen to generate different levels of PAH bioavailability and cometabolism within the reactors. Based on the accurate modelling of PAH sorption in sludge, the aqueous fraction (including free and sorbed-to-dissolved-and-colloidal-matter PAHs) was demonstrated to be bioavailable, which validated a widespread assumption about micropollutants bioavailability in sludge. It was also demonstrated that bioavailability is not the only influencing factor. Indeed, PAHs biodegradation resulted from a combination of bioavailability and cometabolism. An equation adapted from Criddle (1993, The Kinetics of Cometabolism. Biotechnology and Bioengineering 41, 1048-1056) that takes into account both mechanisms was shown to fit the experimental data, with dry matter removal rate identified as the criteria for cometabolism. The existence of a threshold of dry matter cometabolism was suggested, below which PAHs removal would not be possible. The parameters of the Criddle equation were demonstrated to depend on PAH molecular structure, and the results suggest that they would also be influenced by substrate composition and microbial population. This research provided original outcomes for the assessment of micropollutants fate. Indeed, the understanding of the driving mechanisms was improved, which has implications for the optimization of micropollutants removal.

  20. [Anaerobic biodegradation of tetrachloroethylene with methanol as co-metabolism substrate].

    Science.gov (United States)

    Li, Hui-di; Yang, Qi; Shang, Hai-tao

    2004-05-01

    Tetrachloroethylene (PCE) is biodegraded by reductive dechlorination in anaerobic condition. PCE degradation by methanol as co-metabolism substrate was studied. Results show that PCE was dechlorinated reductively to DCEs and TCE, probable VC and ethene. DCEs, VC and ethene are probably end products. It also shows that PCE, TCE degradation and TCE production fit in first order kinetics. Reaction rate constants for PCE and TCE were 0.8991 d(-1) and 0.068 d(-1) respectively. Half-live were 0.77 d and 10.19 d respectively. TCE production rate constant was 0.1333 d(-1). Rate constants show that PCE is degraded more rapidly than TCE. Production rate of TCE is higher than degradation rate of TCE, so TCE exists through the experiment.

  1. Biodegradation and chemical precipitation of dissolved nutrients in anaerobically digested sludge dewatering centrate.

    Science.gov (United States)

    Galvagno, G; Eskicioglu, C; Abel-Denee, M

    2016-06-01

    The objective of this research was to assess specific side-stream treatment processes for biodegradation and precipitation of dissolved nutrients in dewatering centrate. In this study, characterization was made of a conventional suspended growth deammonification treatment process for transforming dissolved polyphosphate (poly-P), dissolved organic phosphorus (DOP) and dissolved organic nitrogen (DON) in two types of dewatering centrate. The deammonification process was configured as a sequencing batch reactor (SBR), combining partial nitrification and anaerobic ammonia oxidation (anammox) in a single tank. The first centrate feed studied was from the full-scale Annacis Island wastewater treatment plant (AIWWTP) located in Metro Vancouver, Canada. The second centrate feed was from a lab-scale anaerobic digester (AD) fed waste sludge from the existing City of Kelowna Wastewater Treatment Facility (KWTF), located in the Okanagan Valley, Canada. In addition, poly aluminum chloride (PACL) dosing was assessed for final polishing of dissolved nutrients. The deammonification SBR (DeSBR) process showed similar treatment characteristics for both the KWTF and AIWWTP centrates with excellent DON removal and poor non-reactive dissolved phosphorus (NRDP) removal. A statistical comparison of the DOP and poly-P through the DeSBR process suggests that DOP has a higher biodegradation potential. Future research focused on understanding the variables associated with degradation of DOP could lead to better NRDP removal through deammonification processes. Utilization of a post-anammox PACL chemical dosing stage can achieve the objective of precipitating any residual DON and NRDP and producing an effluent that has lower dissolved nutrients than the pre-digestion KWTF dewatering centrate scenario.

  2. Assessment of models for anaerobic biodegradation of a model bioplastic: Poly(hydroxybutyrate-co-hydroxyvalerate).

    Science.gov (United States)

    Ryan, Cecily A; Billington, Sarah L; Criddle, Craig S

    2017-03-01

    Kinetic models of anaerobic digestion (AD) are widely applied to soluble and particulate substrates, but have not been systematically evaluated for bioplastics. Here, five models are evaluated to determine their suitability for modeling of anaerobic biodegradation of the bioplastic poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV): (1) first-order kinetics with and without a lag phase, (2) two-step first-order, (3) Monod (4) Contois, and (5) Gompertz. Three models that couple biomass growth with substrate hydrolysis (Monod, Contois, and Gompertz) gave the best overall fits for the data (R(2)>0.98), with reasonable estimates of ultimate CH4 production. The particle size limits of these models were then evaluated. Below a particle size of 0.8mm, rates of hydrolysis and acetogenesis exceeded rates of methanogenesis with accumulation of intermediates leading to a temporary inhibition of CH4 production. Based on model fit and simplicity, the Gompertz model is recommended for applications in which particle size is greater than 0.8mm.

  3. Quantitative Structure-activity Relationships for Anaerobic Biodegradation of Substituted Azobenzenes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-yi; ZHU Huai-wu; LUO Shi-xia; WANG Zheng-wu; XIAO Han

    2004-01-01

    The degradation rates of the azo-bonds of a series of substituted azobenzenes caused by anaerobic sludge digestion were determined by measuring the biggest change of the absorption peak area of the UV-Vis spectra of the anaerobic sludge system before and after degradation. The electronic structure of the molecules was calculated by using the quantum chemistry semiempirical method AM1. The research on the correlation between the biodegradability of the azo-bond and the molecular structure descriptors has led to the following results. (1) There is an obvious relationship between the degradation rate D and the difference Δqπ in π-charge density of the azo-bond. (2) The different substituents in the molecules result in a wave pattern of π-charge distribution and the increasing of the flowability of π-electron. A good flowability of the π-charge favors the reduction between electron contributing azo groups. (3) The effect of the substituents on the π-electron system depends on the electromerization of the substituents in combination with the conjugated systems.

  4. Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments.

    Science.gov (United States)

    Ariyarathna, Thivanka; Vlahos, Penny; Smith, Richard W; Fallis, Stephen; Groshens, Thomas; Tobias, Craig

    2017-05-01

    The lack of knowledge on the fate of explosive compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), particularly in marine ecosystems, constrains the application of bioremediation techniques in explosive-contaminated coastal sites. The authors present a comparative study on anaerobic biodegradation and mineralization of (15) N-nitro group isotopically labeled TNT and RDX in organic carbon-rich, fine-grained marine sediment with native microbial assemblages. Separate sediment slurry experiments were carried out for TNT and RDX at 23°C for 16 d. Dissolved and sediment-sorbed fractions of parent and transformation products, isotopic compositions of sediment, and mineralization products of the dissolved inorganic N pool ((15) NH4(+) ,(15) NO3(-) ,(15) NO2(-) , and (15) N2 ) were measured. The rate of TNT removal from the aqueous phase was faster (0.75 h(-1) ) than that of RDX (0.37 h(-1) ), and (15) N accumulation in sediment was higher in the TNT (13%) than the RDX (2%) microcosms. Mono-amino-dinitrotoluenes were identified as intermediate biodegradation products of TNT. Two percent of the total spiked TNT-N is mineralized to dissolved inorganic N through 2 different pathways: denitration as well as deamination and formation of NH4(+) , facilitated by iron and sulfate reducing bacteria in the sediments. The majority of the spiked TNT-N (85%) is in unidentified pools by day 16. Hexahydro-1,3,5-trinitro-1,3,5-triazine (10%) biodegrades to nitroso derivatives, whereas 13% of RDX-N in nitro groups is mineralized to dissolved inorganic N anaerobically by the end of the experiment. The primary identified mineralization end product of RDX (40%) is NH4(+) , generated through either deamination or mono-denitration, followed by ring breakdown. A reasonable production of N2 gas (13%) was seen in the RDX system but not in the TNT system. Sixty-eight percent of the total spiked RDX-N is in an unidentified pool by day 16 and may include

  5. Anaerobic biodegradation of polycyclic aromatic hydrocarbons with amendment of iron(III) in mangrove sediment slurry.

    Science.gov (United States)

    Li, Chun-Hua; Wong, Yuk-Shan; Tam, Nora Fung-Yee

    2010-11-01

    Mangrove sediment, influenced by tidal cycles, switches between low-oxygen and non-oxygen conditions, and iron is abundant in it. Polycyclic aromatic hydrocarbon (PAH) contamination often occurs in mangrove wetlands. In the present paper, the effects of iron [Fe(III)] amendment on the biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), in mangrove sediment slurries, with and without the inoculation of the enriched PAH-degrading bacterial consortia, under low-oxygen (2 + or - 0.3% O(2)) and non-oxygen (0% O(2)) conditions were investigated. Under both oxygen conditions and for all four PAHs, the highest PAHs biodegradation was observed in the groups with the inoculation of the enriched PAH-degrading consortia, while the groups without the inoculum and without Fe(III) amendment had the lowest biodegradation. However, the amendment of Fe(III) did not show any significant improvement on the biodegradation of all the four mixed PAHs.

  6. Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments.

    Science.gov (United States)

    Ye, Mao; Sun, Mingming; Ni, Ni; Chen, Yinwen; Liu, Zongtang; Gu, Chengang; Bian, Yongrong; Hu, Feng; Li, Huixin; Kengara, Fredrick Orori; Jiang, Xin

    2014-01-01

    The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO3) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1%, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.

  7. Anaerobic biodegradation of benzene series compounds by mixed cultures based on optional electronic acceptors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene,toluene,ethylbenzene and three xylene isomers (BTEX) under nitrate,sulfate and ferric iron reducing conditions.The results showed that toluene,ethylbenzeoe,m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate,sulfate and ferric iron reduction.Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes.Alkylbenzenes can serve as the primary substrates to stimulate the transformation of benzene and p-xylene under anaerobic conditions.Benzene and p-xylene are more toxic than toluene and ethylbenzene,under the three terminal electron acceptors conditions,the degradation rates decreased with toluene > ethylbenzene > m-xylene > o-xylene > benzene > p-xylene.Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron.The ratio between sulfate consumed and the loss of benzene,toluene,ethylbenzene,o-xylene,m-xylene,p-xylene was 4.44,4.51,4.42,4.32,4.37 and 4.23,respectively;the ratio between nitrate consumed and the loss of these substrates was 7.53,6.24,6.49,7.28,7.81,7.61,respectively;the ratio between the consumption of ferric iron and the loss of toluene,ethylbenzene,o-xylene,m-xylenewas 17.99,18.04,18.07,17.97,respectively.

  8. Anaerobic in situ biodegradation of TNT using whey as an electron donor: a case study.

    Science.gov (United States)

    Innemanová, Petra; Velebová, Radka; Filipová, Alena; Čvančarová, Monika; Pokorný, Petr; Němeček, Jan; Cajthaml, Tomáš

    2015-12-25

    Contamination by 2,4,6-trinitrotoluene (TNT), an explosive extensively used by the military, represents a serious environmental problem. In this study, whey has been selected as the most technologically and economically suitable primary substrate for anaerobic in situ biodegradation of TNT. Under laboratory conditions, various additions of whey, molasses, acetate and activated sludge as an inoculant were tested and the process was monitored using numerous chemical analyses including phospholipid fatty acid analysis. The addition of whey resulted in the removal of more than 90% of the TNT in real contaminated soil (7 mg kg(-1) and 12 mg kg(-1) of TNT). The final bioremediation strategy was suggested on the basis of the laboratory results and tested under real conditions at a TNT contaminated site in the Czech Republic. During the pilot test, three repeated injections of whey suspension into the sandy aquifer were performed over a 10-month period. In total, approximately 5m(3) of whey were used. A substantial decrease in the TNT groundwater concentration from the original levels (equalling 1.49 mg l(-1) to 8.58 mg l(-1)) was observed in most of the injection wells, while the concentrations of the TNT biotransformation products were found to be elevated. Pilot-scale application results showed that the anoxic and/or anaerobic conditions in the aquifer were sufficient for TNT bio-reduction by autochthonous microorganisms. Whey application was not accompanied by undesirable effects such as a substantial decrease in the pH or clogging of the wells. The results of the study document the suitability of application of whey to bioremediate TNT contaminated sites in situ.

  9. Performance evaluation of an Anaerobic Migrating Blanket Reactor in the biodegradation of perchloroethylene from industrial wastewaters

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2012-01-01

    Full Text Available Aims: The aim of this study is to determine the PCE biodegradation potential in an Anaerobic Migrating Blanket Reactor (AMBR that has not been used so far for the bioremediation of this compound, in high concentration, and to evaluate the system performance. Materials and Methods: This study was an Experimental - Interventional study that was done from April 2010 to March 2011, in the Isfahan University of Medical Sciences. The AMBR was used in a type of laboratory scale, with a volume of 10 L, which was divided into four compartments, for the biological degradation of PCE in a synthetic substrate. The startup was done using anaerobic digested sewage sludge. The performance of the reactor was evaluated during four periods, with a PCE loading rate of 3.75 until 75 mg PCE/L.d. The hydraulic retention time (HRT was 32 hours. Results: Optimum chemical oxygen demand (COD removal efficiency was obtained, 98%, with an organic loading rate (OLR equal to 3.1 g COD/L.d. For PCE removal, the optimum efficiency was observed to be 99.8%, with a PCE loading rate equal to 37.5 mg PCE/L.d. The average COD and PCE removal rates for the whole activity period of the reactor were 91.4 and 99.5%, respectively; 1.1 ± 0.7% from the influent PCE was adsorbed on the biomass and 20% was found in the headspace. Conclusions: The AMBR reactor, which provides full-scale studies and uses real industrial wastewater polluted with PCE, is a simple, efficient, and reliable method for the treatment of PCE.

  10. Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California

    Science.gov (United States)

    Lorenson, T.D.; Wong, Florence L.; Dartnell, Peter; Sliter, Ray W.

    2014-01-01

    Significant offshore asphaltic deposits with active seepage occur in the Santa Barbara Channel offshore southern California. The composition and isotopic signatures of gases sampled from the oil and gas seeps reveal that the coexisting oil in the shallow subsurface is anaerobically biodegraded, generating CO2 with secondary CH4 production. Biomineralization can result in the consumption of as much as 60% by weight of the original oil, with 13C enrichment of CO2. Analyses of gas emitted from asphaltic accumulations or seeps on the seafloor indicate up to 11% CO2 with 13C enrichment reaching +24.8‰. Methane concentrations range from less than 30% up to 98% with isotopic compositions of –34.9 to –66.1‰. Higher molecular weight hydrocarbon gases are present in strongly varying concentrations reflecting both oil-associated gas and biodegradation; propane is preferentially biodegraded, resulting in an enriched 13C isotopic composition as enriched as –19.5‰. Assuming the 132 million barrels of asphaltic residues on the seafloor represent ~40% of the original oil volume and mass, the estimated gas generated is 5.0×1010 kg (~76×109 m3) CH4 and/or 1.4×1011 kg CO2 over the lifetime of seepage needed to produce the volume of these deposits. Geologic relationships and oil weathering inferences suggest the deposits are of early Holocene age or even younger. Assuming an age of ~1,000 years, annual fluxes are on the order of 5.0×107 kg (~76×106 m3) and/or 1.4×108 kg for CH4 and CO2, respectively. The daily volumetric emission rate (2.1×105 m3) is comparable to current CH4 emission from Coal Oil Point seeps (1.5×105 m3/day), and may be a significant source of both CH4 and CO2 to the atmosphere provided that the gas can be transported through the water column.

  11. Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California

    Science.gov (United States)

    Lorenson, Thomas D.; Wong, Florence L.; Dartnell, Peter; Sliter, Ray W.

    2014-06-01

    Significant offshore asphaltic deposits with active seepage occur in the Santa Barbara Channel offshore southern California. The composition and isotopic signatures of gases sampled from the oil and gas seeps reveal that the coexisting oil in the shallow subsurface is anaerobically biodegraded, generating CO2 with secondary CH4 production. Biomineralization can result in the consumption of as much as 60% by weight of the original oil, with 13C enrichment of CO2. Analyses of gas emitted from asphaltic accumulations or seeps on the seafloor indicate up to 11% CO2 with 13C enrichment reaching +24.8‰. Methane concentrations range from less than 30% up to 98% with isotopic compositions of -34.9 to -66.1‰. Higher molecular weight hydrocarbon gases are present in strongly varying concentrations reflecting both oil-associated gas and biodegradation; propane is preferentially biodegraded, resulting in an enriched 13C isotopic composition as enriched as -19.5‰. Assuming the 132 million barrels of asphaltic residues on the seafloor represent ~40% of the original oil volume and mass, the estimated gas generated is 5.0×1010 kg (~76×109 m3) CH4 and/or 1.4×1011 kg CO2 over the lifetime of seepage needed to produce the volume of these deposits. Geologic relationships and oil weathering inferences suggest the deposits are of early Holocene age or even younger. Assuming an age of ~1,000 years, annual fluxes are on the order of 5.0×107 kg (~76×106 m3) and/or 1.4×108 kg for CH4 and CO2, respectively. The daily volumetric emission rate (2.1×105 m3) is comparable to current CH4 emission from Coal Oil Point seeps (1.5×105 m3/day), and may be a significant source of both CH4 and CO2 to the atmosphere provided that the gas can be transported through the water column.

  12. Electro-Fenton pretreatment for the improvement of tylosin biodegradability

    OpenAIRE

    Ferrag-Siagh, Fatiha; Fourcade, Florence; Soutrel, Isabelle; Aït-Amar, Hamid; Djelal, Hayet; Amrane, Abdelatif

    2014-01-01

    International audience; The feasibility of an electro-Fenton process to treat tylosin (TYL), a non-biodegradable antibiotic, was examined in a discontinuous electrochemical cell with divided cathodic and anodic compartments. Only 15 min electrolysis was needed for total tylosin degradation using a carbon felt cathode and a platinum anode; while 6 h electrolysis was needed to achieve high oxidation and mineralization yields, 96 and 88 % respectively. Biodegradability improvement was shown sinc...

  13. Substrate interactions during anaerobic biodegradation of BTEX by the mixed cultures under nitrate reducing conditions.

    Science.gov (United States)

    Dou, Junfeng; Liu, Xiang; Hu, Zhifeng

    2008-10-30

    The enriched BTEX-degrading bacteria were used to investigate the substrate interactions during anaerobic biodegradation of all the possible BTEX binary combinations. Beneficial and detrimental substrate interactions were observed in comprehensive mixtures of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene. The amendment of toluene or ethylbenzene could stimulate benzene degradation. Lower concentrations of m-xylene would enhance the degradation of benzene, whereas degradation of benzene was inhibited with higher concentrations of m-xylene. The simultaneous presence of toluene and ethylbenzene could stimulate the degradation of each other. The addition of toluene stimulated o-xylene degradation, whereas the amendment of ethylbenzene inhibited the degradation of o-xylene. Lower concentrations of toluene or ethylbenzene would enhance the degradation of m-xylene and p-xylene, whereas higher concentrations of toluene or ethylbenzene had a slight inhibitory effect on m-xylene and p-xylene degradation. The amendment of benzene, m-xylene or p-xylene would inhibit the degradation of other BTEX compounds. When the concentration of BTEX mixtures was over 150 mg/l, the degradation of benzene, o-xylene, m-xylene and p-xylene was severely inhibited.

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

    Science.gov (United States)

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

    2010-06-01

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

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

    Science.gov (United States)

    Tiantao Zhao; Lijie Zhang; Youcai Zhao

    2010-04-01

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

  16. Anaerobic Biodegradability and Methane Potential of Crop Residue Co-Digested with Buffalo Dung

    Directory of Open Access Journals (Sweden)

    Abdul Razaque Sahito

    2013-07-01

    Full Text Available ABD (Anaerobic Biodegradability and BMP (Biochemical Methane Potential of banana plant waste, canola straw, cotton stalks, rice straw, sugarcane trash and wheat straw co-digested with buffalo dung was evaluated through AMPTS (Automatic Methane Potential Test System. The substrates were analyzed for moisture, TS (Total Solids and VS (Volatile Solids, ultimate analysis (CHONS, pH and TA (Total Alkalinity. The BMPobserved during incubation of 30 days at the temperature of 37±0.2°C was 322 Nml CH4/g VSadd for wheat straw followed by 260, 170, 149, 142 and 138 Nml CH4/gVSadd for canola straw, rice straw, cotton stalks, banana plant waste and sugarcane trash respectively, whereas the maximum theoretical BMP was 481 Nml CH4/gVSadd for cotton stalks, followed by 473, 473, 446, 432 and 385 Nml CH4/gVSadd for wheat straw, banana plant waste, canola straw, rice straw and sugarcane trash respectively. The percentage ABD values were in the range of 68-30%. In addition to this, the effect of lignin content in the crop residue was evaluated on the ABD. The results of this study indicate that, the co-digestion of the crop residues with buffalo dung is feasible for production of renewable methane

  17. Potential of Biogas Power Plant Produced by Anaerobic Digestion of Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Nur Shuhada Ghazali

    2013-09-01

    Full Text Available Biogas typically refers to a gas produced by the breakdown of organic matter in the absence of oxygen. It is a renewable energy source, like solar and wind energy. Furthermore, biogas can be produced from regionally available raw materials and recycled waste and is environmentally friendly and CO2 neutral. Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials such as manure, sewage, municipal waste, green waste, plant material, and crops. Biogas comprises primarily methane (CH4 and carbon dioxide (CO2 and may have small amounts of hydrogen sulphide (H2S, moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel. Biogas can be compressed, much like natural gas, and used to power motor vehicles. Biogas is a renewable fuel so it qualifies for renewable energy subsidies in some parts of the world. Biogas can also be cleaned and upgraded to natural gas standards when it becomes bio methane. This paper will discuss the potential of biogas in order to provide a clean, easily controlled source of renewable energy from organic waste materials for a small labour input, replacing firewood or fossil fuels which are becoming more expensive as supply falls behind demand.

  18. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Hoyos-Hernandez, Carolina; Hoffmann, Marieke; Guenne, Angeline; Mazeas, Laurent

    2014-02-01

    Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55°C was followed using an isotopic tracing approach ((13)C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate. Benzoate is known to be a phenol metabolite under mesophilic conditions, but in this study it was found for the first time to be a phenol degradation product at thermophilic temperature.

  19. Vertical distribution and anaerobic biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments in Hong Kong, South China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun-Hua [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Zhou, Hong-Wei [Department of Environmental Health Science, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou (China); Wong, Yuk-Shan [Department of Biology, The Hong Kong University of Science and Technology (Hong Kong); Tam, Nora Fung-Yee, E-mail: bhntam@cityu.edu.hk [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2009-10-15

    The vertical distribution of polycyclic aromatic hydrocarbons (PAHs) at different sediment depths, namely 0-2 cm, 2-4 cm, 4-6 cm, 6-10 cm, 10-15 cm and 15-20 cm, in one of the most contaminated mangrove swamps, Ma Wan, Hong Kong was investigated. It was the first time to study the intrinsic potential of deep sediment to biodegrade PAHs under anaerobic conditions and the abundance of electron acceptors in sediment for anaerobic degradation. Results showed that the total PAHs concentrations (summation of 16 US EPA priority PAHs) increased with sediment depth. The lowest concentration (about 1300 ng g{sup -1} freeze-dried sediment) and the highest value (around 5000 ng g{sup -1} freeze-dried sediment) were found in the surface layer (0-2 cm) and deeper layer (10-15 cm), respectively. The percentage of high molecular weight (HMW) PAHs (4 to 6 rings) to total PAHs was more than 89% at all sediment depths. The ratio of phenanthrene to anthracene was less than 10 while fluoranthene to pyrene was around 1. Negative redox potentials (Eh) were recorded in all of the sediment samples, ranging from - 170 to - 200 mv, with a sharp decrease at a depth of 6 cm then declined slowly to 20 cm. The results suggested that HMW PAHs originated from diesel-powered fishing vessels and were mainly accumulated in deep anaerobic sediments. Among the electron acceptors commonly used by anaerobic bacteria, sulfate was the most dominant, followed by iron(III), nitrate and manganese(IV) was the least. Their concentrations also decreased with sediment depth. The population size of total anaerobic heterotrophic bacteria increased with sediment depth, reaching the peak number in the middle layer (4-6 cm). In contrast, the aerobic heterotrophic bacterial count decreased with sediment depth. It was the first time to apply a modified electron transport system (ETS) method to evaluate the bacterial activities in the fresh sediment under PAH stress. The vertical drop of the ETS activity suggested that

  20. Anaerobic biodegradability and methanogenic toxicity of key constituents in copper chemical mechanical planarization effluents of the semiconductor industry.

    Science.gov (United States)

    Hollingsworth, Jeremy; Sierra-Alvarez, Reyes; Zhou, Michael; Ogden, Kimberly L; Field, Jim A

    2005-06-01

    Copper chemical mechanical planarization (CMP) effluents can account for 30-40% of the water discharge in semiconductor manufacturing. CMP effluents contain high concentrations of soluble copper and a complex mixture of organic constituents. The aim of this study is to perform a preliminary assessment of the treatability of CMP effluents in anaerobic sulfidogenic bioreactors inoculated with anaerobic granular sludge by testing individual compounds expected in the CMP effluents. Of all the compounds tested (copper (II), benzotriazoles, polyethylene glycol (M(n) 300), polyethylene glycol (M(n) 860) monooleate, perfluoro-1-octane sulfonate, citric acid, oxalic acid and isopropanol) only copper was found to be inhibitory to methanogenic activity at the concentrations tested. Most of the organic compounds tested were biodegradable with the exception of perfluoro-1-octane sulfonate and benzotriazoles under sulfate reducing conditions and with the exception of the same compounds as well as Triton X-100 under methanogenic conditions. The susceptibility of key components in CMP effluents to anaerobic biodegradation combined with their low microbial inhibition suggest that CMP effluents should be amenable to biological treatment in sulfate reducing bioreactors.

  1. Effects of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part II: Oleic acid toxicity and biodegradability.

    Science.gov (United States)

    Alves, M M; Vieira, J A; Pereira, R M; Pereira, M A; Mota, M

    2001-01-01

    Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic fixed-bed units. When treating an oleate based effluent, the sludge from the bioreactor that was acclimated with lipids during the first operation period, showed a higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) compared with the sludge fed with a non-fat substrate (IC50 = 80 mg/l). This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l. When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g. stearate that was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day. This suggests the possibility of using adsorption-degradation cycles for the treatment of LCFA based effluents. Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.

  2. Anaerobic biodegradation of soybean biodiesel and diesel blends under sulfate-reducing conditions.

    Science.gov (United States)

    Wu, Shuyun; Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

    2016-10-01

    Biotransformation of soybean biodiesel and its biodiesel/petrodiesel blends were investigated under sulfate-reducing conditions. Three blends of biodiesel, B100, B50, and B0, were treated using microbial cultures pre-acclimated to B100 (biodiesel only) and B80 (80% biodiesel and 20% petrodiesel). Results indicate that the biodiesel could be effectively biodegraded in the presence or absence of petrodiesel, whereas petrodiesel could not be biodegraded at all under sulfate-reducing conditions. The kinetics of biodegradation of individual Fatty Acid Methyl Ester (FAME) compounds and their accompanying sulfate-reduction rates were studied using a serum bottle test. As for the biodegradation of individual FAME compounds, the biodegradation rates for the saturated FAMEs decreased with increasing carbon chain length. For unsaturated FAMEs, biodegradation rates increased with increasing number of double bonds. The presence of petrodiesel had a greater effect on the rate of biodegradation of biodiesel than on the extent of removal.

  3. Volatile organic sulfur compounds in anaerobic sludge and sediments: biodegradation and toxicity

    NARCIS (Netherlands)

    Leerdam, van R.C.; Bok, de F.A.M.; Lomans, B.P.; Stams, A.J.M.; Lens, P.N.L.; Janssen, A.J.H.

    2006-01-01

    A variety of environmental samples was screened for anaerobic degradation of methanethiol, ethanethiol, propanethiol, dimethylsulfide, and dimethyldisulfide. All sludge and sediment samples degraded methanethiol, dimethylsulfide, and dimethyldisulfide anaerobically. In contrast, ethanethiol and prop

  4. Application of fuzzy neural networks for modeling of biodegradation and biogas production in a full-scale internal circulation anaerobic reactor.

    Science.gov (United States)

    Ruan, Jujun; Chen, Xiaohong; Huang, Mingzhi; Zhang, Tao

    2017-01-02

    This paper presents the development and evaluation of three fuzzy neural network (FNN) models for a full-scale anaerobic digestion system treating paper-mill wastewater. The aim was the investigation of feasibility of the approach-based control system for the prediction of effluent quality and biogas production from an internal circulation (IC) anaerobic reactor system. To improve FNN performance, fuzzy subtractive clustering was used to identify model's architecture and optimize fuzzy rule, and a total of 5 rules were extracted in the IF-THEN format. Findings of this study clearly indicated that, compared to NN models, FNN models had smaller RMSE and MAPE as well as bigger R for the testing datasets than NN models. The proposed FNN model produced smaller deviations and exhibited a superior predictive performance on forecasting of both effluent quality and biogas (methane) production rates with satisfactory determination coefficients greater than 0.90. From the results, it was concluded that FNN modeling could be applied in IC anaerobic reactor for predicting the biodegradation and biogas production using paper-mill wastewater.

  5. Effects of biodegradation of mecoprop, dichlorprop and bentazone by changing the redox conditions from anaerobic to aerobic in sandy aquifer

    DEFF Research Database (Denmark)

    Levi, Suzi; Bjerg, Poul Løgstrup; Albrechtsen, Hans-Jørgen

    2011-01-01

    in combination with geological variations may affect microbial degradation processes by mixing in even low oxygen concentrations and create steep gradients and drastic redox zones in aquifers. The aim of the current study was to investigate the stimulation of pesticides biodegradation by adding oxygen...... knowledge, this is the first observation of bentazone degradation with aquifer. Optimization of redox conditions from anaerobic to aerobic by adding oxygen stimulated the biodegradation of three pesticides.......Pesticides and metabolites are detected in an increasing number of aquifers resulting in closure of many drinking water wells. The natural redox conditions of aquifers are considered to be one of the important factors governing the pesticides degradation in groundwater. Water abstraction strategy...

  6. Two-Dimensional Stable Isotope Fractionation During Aerobic and Anaerobic Alkane Biodegradation and Implications for the Field

    Science.gov (United States)

    El Morris, Brandon; Suflita, Joseph M.; Richnow, Hans-Hermann

    2010-05-01

    Quantitatively, n-alkanes comprise a major portion of most crude oils. In petroliferous formations, it may be possible to relate the loss of these compounds to the levels of biodegradation occurring in situ [1]. Moreover, it is important to develop indicators of alkane degradation that may be used to monitor bioremediation of hydrocarbon-impacted environments. Desulfoglaeba alkanexedens and Pseudomonas putida GPo1 were used to determine if carbon and hydrogen stable isotope fractionation could differentiate between n-alkane degradation under anaerobic and aerobic conditions, respectively in the context of the Rayleigh equation model [2]. Bacterial cultures were sacrificed by acidification and headspace samples were analyzed for stable isotope composition using gas chromatography-isotope ratio mass spectrometry. Carbon enrichment factors (bulk) for anaerobic and aerobic biodegradation of hexane were -5.52 ± 0.2‰ and -4.34 ± 0.3‰, respectively. Hydrogen enrichment during hexane degradation was -43.14 ± 6.32‰ under sulfate-reducing conditions, and was too low for quantification during aerobiosis. Collectively, this indicates that the correlation between carbon and hydrogen stable isotope fractionation (may be used to help elucidate in situ microbial processes in oil reservoirs, and during intrinsic as well as engineered remediation efforts. References 1. Asif, M.; Grice, K.; Fazeelat, T., Assessment of petroleum biodegradation using stable hydrogen isotopes of individual saturated hydrocarbon and polycyclic aromatic hydrocarbon distributions in oils from the Upper Indus Basin, Pakistan. Organic Geochemistry 2009, 40, (3), 301-311. 2. Fischer, A.; Herklotz, I.; Herrmann, S.; Thullner, M.; Weelink, S. A. B.; Stams, A., J. M.; Schloemann, M.; Richnow, H.-H.; Vogt, C., Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways. Environ. Sci. Technol. 2008, 42, 4356-4363.

  7. Optimization of struvite crystallization protocol for pretreating the swine wastewater and its impact on subsequent anaerobic biodegradation of pollutants.

    Science.gov (United States)

    Zhang, Dong-mei; Chen, Ying-xu; Jilani, Ghulam; Wu, Wei-xiang; Liu, Wen-li; Han, Zhi-ying

    2012-07-01

    Higher contents of NH(4)(+) and SS in wastewater hamper the anaerobic digestion; necessitating its pretreatment to reduce them. This study reveals optimization of struvite/MAP precipitation protocol followed by anaerobic digestion of pretreated swine wastewater for pollutants removal. Levels of different treatments: stirring speeds, 400 and 160 rpm; pH values, 9.0, 9.5, 10.0, 10.5, 11.0 and 11.5; and P:Mg:N ratios, 1:1:1.2, 1:1:1.7, 1:1:2.2, 1:1:2.7, 1:1:4.0 and 1:1:5.0 were evaluated for MAP crystallization. Among various combinations, protocol comprising of initial 10 min stirring at 400 rpm followed by 160 rpm for 30 min, pH 10.0, and P:Mg:N ratio 1:1:1.2 rendered the best removal efficiency for NH(4)(+), PO(4)(3-), COD, TC and TOC. Subsequent anaerobic biodegradation revealed superiority of MAP supernatant over raw swine wastewater for methane yield and NH(4)(+)-N, PO(4)(3-)-P, COD, TC and TOC removals. It suggests that struvite precipitation as pretreatment to anaerobic digestion is highly effective and advantageous in wastewater treatment.

  8. Coupled anaerobic/aerobic biodegradation of 2,4,6 trichlorophenol

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Degradation of 2, 4, 6-trichlorophenol(TCP) with co-immobilizing anaerobic granular sludge and isolated aerobic bacterial specieswas studied in coupled anaerobic/aerobic integrated reactors. The synergism of aerobes and anaerobes within co-immobilized granule mightfacilitate degrading the TCP and exchange of anaerobic metabolites 4-CP, which promoted system organic removal efficiency and recovered fromorganic shock-loads more quickly. The biomass specific activities experiment further confirmed that strict anaerobes be not affected over thecourse of this experiment by the presence of an oxic environment, aerobic activity predominated in the outer co-immobilized granule layers,while the interior was characterized by anaerobic activity. The co-immobilized granule could thus enable both aerobic and anaerobic microbesfunction in the same reactor and thereby integrate the oxidative and reductive catabolism.

  9. Biodegradation and speciation of roxarsone in an anaerobic granular sludge system and its impacts.

    Science.gov (United States)

    Zhang, Fei-Fei; Wang, Wei; Yuan, Shou-Jun; Hu, Zhen-Hu

    2014-08-30

    Roxarsone (3-nitro-4-hydroxy benzene arsenic acid) is an organoarsenic feed additive and has been widely used in the poultry industry to prevent coccidiosis and improve feed efficiency. The presence of roxarsone and its degradation products results in the instability of the anaerobic methanogenic process. This study investigated the degradation and speciation of roxarsone in an anaerobic granular sludge (AGS) system and the impacts of roxarsone and its degradation products on the structure of AGS. Roxarsone inhibited methane production, and the added roxarsone was rapidly degraded into 3-amino-4-hydroxyphenylarsonic acid (HAPA). After 240 days of incubation, the distribution of arsenic differed between the aqueous solution and the AGS in the assays of 20 and 350mg/L roxarsone. Species analysis indicated that HAPA was completely degraded in all of the assays with roxarsone addition after 240 days of incubation. Species distribution was affected by the phases and the initial concentration of roxarsone added. The concentration of As(III) was higher than that of As(V) in both the aqueous solution and the AGS in all assays with roxarsone addition. The toxicity of roxarsone and its degradation products resulted in changes in the structure and the microorganism species in the AGS.

  10. The effect of salinity, redox mediators and temperature on anaerobic biodegradation of petroleum hydrocarbons in microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Adelaja, Oluwaseun, E-mail: o.adelaja@my.westminster.ac.uk; Keshavarz, Tajalli, E-mail: t.keshavarz@westminster.ac.uk; Kyazze, Godfrey, E-mail: g.kyazze@westminster.ac.uk

    2015-02-11

    Highlights: • Effective degradation of petroleum hydrocarbon mixtures was achieved using MFC. • Adapted anaerobic microbial consortium was used as inoculum. • Bio-electricity generation was enhanced by 30-fold when riboflavin, was added. • Optimum MFC performance was obtained at mesophilic and moderately saline conditions. • Stable MFC performance was obtained during prolonged fed-batch MFC operation. - Abstract: Microbial fuel cells (MFCs) need to be robust if they are to be applied in the field for bioremediation. This study investigated the effect of temperature (20–50 °C), salinity (0.5–2.5% (w/v) as sodium chloride), the use of redox mediators (riboflavin and anthraquinone-2-sulphonate, AQS) and prolonged fed-batch operation (60 days) on biodegradation of a petroleum hydrocarbon mix (i.e. phenanthrene and benzene) in MFCs. The performance criteria were degradation efficiency, % COD removal and electrochemical performance. Good electrochemical and degradation performance were maintained up to a salinity of 1.5% (w/v) but deteriorated by 35-fold and 4-fold respectively as salinity was raised to 2.5%w/v. Degradation rates and maximum power density were both improved by approximately 2-fold at 40 °C compared to MFC performance at 30 °C but decreased sharply by 4-fold when operating temperature was raised to 50 °C. The optimum reactor performance obtained at 40 °C was 1.15 mW/m{sup 2} maximum power density, 89.1% COD removal and a degradation efficiency of 97.10%; at moderately saline (1% w/v) conditions the maximum power density was 1.06 mW/m{sup 2}, 79.1% COD removal and 91.6% degradation efficiency. This work suggests the possible application of MFC technology in the effective treatment of petroleum hydrocarbons contaminated site and refinery effluents.

  11. Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

    Science.gov (United States)

    Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

    2016-03-01

    Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water.

  12. Formation of metabolites during biodegradation of linear alkylbenzene sulfonate in an upflow anaerobic sludge bed reactor under thermophilic conditions.

    Science.gov (United States)

    Mogensen, A S; Ahring, B K

    2002-03-05

    Biodegradation of linear alkylbenzene sulfonate (LAS) was shown in an upflow anaerobic sludge blanket reactor under thermophilic conditions. The reactor was inoculated with granular biomass and fed with a synthetic medium and 3 micromol/L of a mixture of LAS with alkylchain length of 10 to 13 carbon atoms. The reactor was operated with a hydraulic retention time of 12 h with effluent recirculation in an effluent to influent ratio of 5 to 1. A sterile reactor operated in parallel revealed that sorption to sludge particles initially accounted for a major LAS removal. After 8 days of reactor operation, the removal of LAS in the reactor inoculated with active granular biomass exceeded the removal in the sterile reactor inoculated with sterile granular biomass. The effect of sorption ceased after 185 to 555 h depending on the LAS homologs. 40% of the LAS was biodegraded, and the removal rate was 0.5 x 10(-6) mol/h/mL granular biomass. Acidified effluent from the reactor was subjected to dichloromethane extraction followed by gas chromatography/mass spectrometry. Benzenesulfonic acid and benzaldehyde were detected in the reactor effluent from the reactor with active granular biomass but not in the sterile and unamended reactor effluent. Benzenesulfonic acid and benzaldehyde are the first identified degradation products in the anaerobic degradation of LAS.

  13. Anaerobic Biodegradation Tests of Poly(lactic acid under Mesophilic and Thermophilic Conditions Using a New Evaluation System for Methane Fermentation in Anaerobic Sludge

    Directory of Open Access Journals (Sweden)

    Hisaaki Yagi

    2009-09-01

    Full Text Available Anaerobic biodegradation tests of poly(lactic acid (PLA powder were done at the thermophilic (55 °C and mesophilic temperature (35 °C under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 °C and 2.24% (at 35 °C] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 °C. On the other hand, the PLA degradation started in 55 days at 35 °C and degradation rate was much slower than at 55 °C.

  14. Asparagus stem as a new lignocellulosic biomass feedstock for anaerobic digestion: increasing hydrolysis rate, methane production and biodegradability by alkaline pretreatment.

    Science.gov (United States)

    Chen, Xiaohua; Gu, Yu; Zhou, Xuefei; Zhang, Yalei

    2014-07-01

    Recently, anaerobic digestion of lignocellulosic biomass for methane production has attracted considerable attention. However, there is little information regarding methane production from asparagus stem, a typical lignocellulosic biomass, by anaerobic digestion. In this study, alkaline pretreatment of asparagus stem was investigated for its ability to increase hydrolysis rate and methane production and to improve biodegradability (BD). The hydrolysis rate increased with increasing NaOH dose, due to higher removal rates of lignin and hemicelluloses. However, the optimal NaOH dose was 6% (w/w) according to the specific methane production (SMP). Under this condition, the SMP and the technical digestion time of the NaOH-treated asparagus stem were 242.3 mL/g VS and 18 days, which were 38.4% higher and 51.4% shorter than those of the untreated sample, respectively. The BD was improved from 40.1% to 55.4%. These results indicate that alkaline pretreatment could be an efficient method for increasing methane production from asparagus stem. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Tenax extraction for exploring rate-limiting factors in methyl-β-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy soil

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Mingming, E-mail: sunmingming@njau.edu.cn [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Key Laboratory of Soil Environmental and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Ye, Mao [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Hu, Feng, E-mail: fenghu@njau.edu.cn [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Li, Huixin [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Teng, Ying [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Luo, Yongming [Yantai Institute of Costal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Jiang, Xin [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Kengara, Fredrick Orori [Department of Chemistry, Maseno University, Private Bag, Maseno 40105 (Kenya)

    2014-01-15

    Highlights: • Enhanced anaerobic bioremediation of a red paddy soil polluted with PAHs. • 1% (w/w) methyl-β-cyclodextrin (MCD) and 20 mM nitrate addition acted as solubility-enhancing agent and electron acceptor respectively. • Tenax extraction and a first-three-compartment modeling were applicable to explore the rate-limiting factors in the biodegradation. • Lack of PAH-degraders hindered biodegradation in control and MCD addition treatments. • Inadequate bioaccessible PAHs was vital rate-limiting factor in nitrate addition treatments. -- Abstract: The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information on what is the rate-limiting factor in bioremediation process is of vital importance in the decision in what measures can be taken to assist the biodegradation efficacy. In the present study, four different microcosms were set to study the effect of methyl-β-cyclodextrin (MCD) and nitrate addition (N) on PAHs biodegradation under anaerobic conditions in a red paddy soil. Meanwhile, sequential Tenax extraction combined with a first-three-compartment model was employed to evaluate the rate-limiting factors in MCD enhanced anaerobic biodegradation of PAHs. Microcosms with both 1% (w/w) MCD and 20 mM N addition produced maximum biodegradation of total PAHs of up to 61.7%. It appears rate-limiting factors vary with microcosms: low activity of degrading microorganisms is the vital rate-limiting factor for control and MCD addition treatments (CK and M treatments); and lack of bioaccessible PAHs is the main rate-limiting factor for nitrate addition treatments (N and MN treatments). These results have practical implications for site risk assessment and cleanup strategies.

  16. Simultaneous anaerobic-aerobic biodegradation of halogenated phenolic compound under oxygen-limited conditions

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuan-cai; LAN Hui-xia; ZHAN Huai-yu; FU Shi-yu

    2005-01-01

    The successful application of co-immobilized aerobic-anaerobic biomaes under limited aeration in wastewater treatment systems would eliminate the problems associated with the intermediates mono-chlorophenol(MCP) and di-chlorophenol(DCP) accumulations. With low initial pentachlorophenol(PCP) concentration, all PCP could be completely removed under oxygen-limited strict anaerobic conditions,and the removal efficiencies with different initial haedspace oxygen percentage(IHOP) were not obviously different from each other. While at high initial PCP concentration, under strictly anaerobic conditions PCP and their intermediates were clearly higher than that under other conditions, and produced obvious accumulation, the highest PCP reduction was achieved by the system receiving 30 IHOP, oxygen-limited system also exhibited lower residual TOC concentration and lower concentration of metabolic intermediates MCP and DCP. These results suggested that under strictly anaerobic condition the reductive dechlorination of low chlorinated compounde became rate limiting in the reductive dechlorination pathway, less chlorinated compounds be more amenable to aerobic degradation, and the aerobes of outer layers could function under limited oxygen. The co-immobilized aerobic-anaerobic biomass for methanogeneeis under limited-aeration for chlorophenol degradation might be an attractive and efficient altemative for the sequential anaerobic/aerobic system to achieve mineralization of a broad range of recalcitrance highly chlorinated organics and low final TOC concentrations.

  17. Dissolution Coupled Biodegradation of Pce by Inducing In-Situ Biosurfactant Production Under Anaerobic Conditions

    Science.gov (United States)

    Dominic, J.; Nambi, I. M.

    2013-12-01

    Biosurfactants have proven to enhance the bioavailability and thereby elevate the rate of degradation of Light Non Aqueous Phase Liquids (LNAPLs) such as crude oil and petroleum derivatives. In spite of their superior characteristics, use of these biomolecules for remediation of Dense Non Aqueous Phase Liquids (DNAPLs) such as chlorinated solvents is still not clearly understood. In this present study, we have investigated the fate of tetrachloroethylene (PCE) by inducing in-situ biosurfactants production, a sustainable option which hypothesizes increase in bioavailability of LNAPLs. In order to understand the effect of biosurfactants on dissolution and biodegradation under the inducement of in-situ biosurfactant production, batch experiments were conducted in pure liquid media. The individual influence of each process such as biosurfactant production, dissolution of PCE and biodegradation of PCE were studied separately for getting insights on the synergistic effect of each process on the fate of PCE. Finally the dissolution coupled biodegradation of non aqueous phase PCE was studied in conditions where biosurfactant production was induced by nitrate limitation. The effect of biosurfactants was differentiated by repeating the same experiments were the biosurfactant production was retarded. The overall effect of in-situ biosurfactant production process was evaluated by use of a mathematical model. The process of microbial growth, biosurfactant production, dissolution and biodegradation of PCE were translated as ordinary differential equations. The modelling exercise was mainly performed to get insight on the combined effects of various processes that determine the concentration of PCE in its aqueous and non-aqueous phases. Model simulated profiles of PCE with the kinetic coefficients evaluated earlier from individual experiments were compared with parameters fitted for observations in experiments with dissolution coupled biodegradation process using optimization

  18. Effect of temperature and organic nutrients on the biodegradation of linear alkylbenzene sulfonate (LAS) during the composting of anaerobically digested sludge from a wastewater treatment plant.

    Science.gov (United States)

    Sanz, E; Prats, D; Rodríguez, M; Camacho, A

    2006-01-01

    Limits on the application of biosolids (anaerobically processed sludges from wastewater treatment plants) as fertilizers for the amendment of soil are becoming greater because of the accumulation of recalcitrant substances, making necessary the use of techniques that bring the concentration of xenobiotics to lower concentrations than those permitted. In general, the biosolids composting process is sufficient to reduce the usual concentration of linear alkylbenzene sulfonates (LAS) to low levels. In this work, an assessment is made on the effect of temperature in the capacity of enriched bacterial populations to biodegrade LAS, together with the influence that the available nutrients may have in the biodegradation of these compounds. The results show that the microbial metabolism of LAS was not observed in the thermophilic range. The optimum temperature for the biodegradation of LAS appears to be around 40 degrees C, this is, the lowest assayed here, and at this temperature the differences in the biodegradation of LAS among the nutritionally supplemented cultures are small.

  19. Microbial community changes in aquifer sediment microcosm for anaerobic anthracene biodegradation under methanogenic condition

    Institute of Scientific and Technical Information of China (English)

    Rui Wan; Shuying Zhang; Shuguang Xie

    2012-01-01

    The widespread distribution of polycyclic aromatic hydrocarbons(PAHs)in groundwater has become an important environmental issue.Knowledge of microbial community changes could aid in identification of particular microorganisms that are capable of degrading PAHs in contaminated aquifers.Therefore,16S rRNA gene clone library analysis was used to identify the archaeal and bacterial communities in an aquifer sediment microcosm used for anaerobic anthracene degradation under methanogenic conditions.A remarkable shift of the archaeal community structure occurred after anaerobic anthracene degradation,but the types of the abundant bacterial phyla did not change.However,a decrease of both archaeal and bacterial diversity was observed.Bacterial genera Bacillus,Rhodococcus and Herbaspirillum might have links with anaerobic anthracene degradation,suggesting a role of microbial consortia.This work might add some new information for understanding the mechanism of PAH degradation under methanogenic conditions.

  20. Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass

    NARCIS (Netherlands)

    Fernandes, T.; Klaasse Bos, G.J.; Zeeman, G.; Sanders, J.P.M.; Lier, van J.B.

    2009-01-01

    The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After pre-

  1. Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass

    NARCIS (Netherlands)

    Fernandes, T.; Klaasse Bos, G.J.; Zeeman, G.; Sanders, J.P.M.; Lier, van J.B.

    2009-01-01

    The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After

  2. Tenax extraction for exploring rate-limiting factors in methyl-β-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy soil.

    Science.gov (United States)

    Sun, Mingming; Ye, Mao; Hu, Feng; Li, Huixin; Teng, Ying; Luo, Yongming; Jiang, Xin; Kengara, Fredrick Orori

    2014-01-15

    The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information on what is the rate-limiting factor in bioremediation process is of vital importance in the decision in what measures can be taken to assist the biodegradation efficacy. In the present study, four different microcosms were set to study the effect of methyl-β-cyclodextrin (MCD) and nitrate addition (N) on PAHs biodegradation under anaerobic conditions in a red paddy soil. Meanwhile, sequential Tenax extraction combined with a first-three-compartment model was employed to evaluate the rate-limiting factors in MCD enhanced anaerobic biodegradation of PAHs. Microcosms with both 1% (w/w) MCD and 20mM N addition produced maximum biodegradation of total PAHs of up to 61.7%. It appears rate-limiting factors vary with microcosms: low activity of degrading microorganisms is the vital rate-limiting factor for control and MCD addition treatments (CK and M treatments); and lack of bioaccessible PAHs is the main rate-limiting factor for nitrate addition treatments (N and MN treatments). These results have practical implications for site risk assessment and cleanup strategies.

  3. Bioavailability of heavy metals in soil: impact on microbial biodegradation of organic compounds and possible improvement strategies.

    Science.gov (United States)

    Olaniran, Ademola O; Balgobind, Adhika; Pillay, Balakrishna

    2013-05-15

    Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.

  4. Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

    Directory of Open Access Journals (Sweden)

    Balakrishna Pillay

    2013-05-01

    Full Text Available Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation, treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.

  5. Anaerobic Biodegradation of Reactive Red KE-3B%活性红KE-3B的厌氧降解

    Institute of Scientific and Technical Information of China (English)

    王天广; 王新海; 马同森; 马骏; 李德亮

    2012-01-01

    考察了活性红KE-3B在中温(35℃)、高温(55℃)条件下的厌氧降解性,从产气量、脱色率、VFAs、CODcr去除率等方面研究了其处理效果和降解机理.结果表明,活性红KE-3B不易被完全矿化,只是发生了初级降解;中温条件下有利于提高生物气中的甲烷比率,但VFAs积累较多,对最终生化降解起到了抑制作用;高温条件下,脱色率随染料的浓度增大而减小,并且在同等条件下比中温时脱色率高,最高达到97.40%,同时高温时的CODCr去除率也相对较高,达到了84.53%.活性红KE-3B废水更适合低浓度高温处理,理想处理浓度≤80 mg/L(以C计).%The anaerobic biodegradability of reactive red KE-3B was studied in batch experiments under mesophilic (35 'C)and thermophilic(55 ℃)conditions, and the factors such as decolorization rate, VFAs,CODr.r removal rate etc, were detected to evaluate its treatment effects and degradation mechanism. The results showed that the reactive red KE-3B was difficult to be anaerobic biodegraded into CO2 and CH4 ultimately, and further to say the decolorization was just due to primary degradation. The ratio of CH4 in biogas was higher under mesophilic condition, but the value of VFAs was high, which had inhibited the ultimate biodegradation. The decolorization rate decreased as the dye concentration increased under thermophilic condition. Compared with the mesophilic tests, the higher decolorization rate was obtained in the thermophilic tests under the same conditions, with the highest decolorization rate of 97. 40 %. The highest CODcr removal rate, which was also higher under thermophilic condition, could attain 84. 53 %. Based on these results, the conclusion to be made was that the treatment of reactive red KE-3B wastewater, was more suitable for low concentration under thermophilic condition, which ideal treatment concentration was ≤80 mg/L(calculated by C).

  6. Quinone-respiration improves dechlorination of carbon tetrachloride by anaerobic sludge

    NARCIS (Netherlands)

    Cervantes, F.J.; Vu-Thi-Thu, L.; Lettinga, G.; Field, J.A.

    2004-01-01

    The impact of humic acids and the humic model compound, anthraquinone-2,6-disulfonate (AQDS), on the biodegradation of carbon tetrachloride (CT) by anaerobic granular sludge was studied. Addition of both humic acids and AQDS at sub-stoichiometric levels increased the first-order rate of conversion o

  7. Anaerobic Biodegradation of Soybean Biodiesel and Diesel Blends under Methanogenic Conditions

    Science.gov (United States)

    Biotransformation of soybean biodiesel and the inhibitory effect of petrodiesel were studied under methanogenic conditions. Biodiesel removal efficiency of more than 95% was achieved in a chemostat with influent biodiesel concentrations up to 2.45 g/L. The kinetics of anaerobic...

  8. Concurrent nitrate and Fe(III) reduction during anaerobic biodegradation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, Mette; Crouzet, C.; Arvin, Erik

    2000-01-01

    in the anaerobic microcosms were mixed nitrate and Fe(III) reducing. Nitrate and Fe(III) were apparently the dominant electron accepters at high and low nitrate concentrations, respectively. When biomass growth is taken into account, nitrate and Fe(III) reduction constituted sufficient electron acceptor capacity...

  9. 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.

  10. Biodegradation and reversible inhibitory impact of sulfamethoxazole on the utilization of volatile fatty acids during anaerobic treatment of pharmaceutical industry wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Cetecioglu, Zeynep, E-mail: cetecioglu@itu.edu.tr [Istanbul Technical University, Environmental Engineering Department, 34469 Maslak, Istanbul (Turkey); Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona (Spain); Ince, Bahar [Bogazici University, Institute of Environmental Sciences, Rumelihisarustu - Bebek, 34342 Istanbul (Turkey); Gros, Meritxell; Rodriguez-Mozaz, Sara; Barceló, Damia [Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona (Spain); Ince, Orhan; Orhon, Derin [Istanbul Technical University, Environmental Engineering Department, 34469 Maslak, Istanbul (Turkey)

    2015-12-01

    This study evaluated the chronic impact and biodegradability of sulfamethoxazole under anaerobic conditions. For this purpose, a lab-scale anaerobic sequencing batch reactor was operated in a sequence of different phases with gradually increasing sulfamethoxazole doses of 1 to 45 mg/L. Conventional parameters, such as COD, VFA, and methane generation, were monitored with corresponding antimicrobial concentrations in the reactor and the methanogenic activity of the sludge. The results revealed that anaerobic treatment was suitable for pharmaceutical industry wastewater with concentrations of up to 40 mg/L of sulfamethoxazole. Higher levels exerted toxic effects on the microbial community under anaerobic conditions, causing the inhibition of substrate/COD utilization and biogas generation and leading to a total collapse of the reactor. The adverse long-term impact was quite variable for fermentative bacteria and methanogenic achaea fractions of the microbial community based on changes inflicted on the composition of the residual organic substrate and mRNA expression of the key enzymes. - Highlights: • Chronic impact of sulfamethoxazole was lethal at 45 mg/L on the microbial community. • Sulfamethoxazole was highly biodegradable under anaerobic conditions. • While the COD removal stopped, the sorption of sulfamethoxazole into the sludge increased. • Sulfamethoxazole has a reversible inhibitory effect on acetoclastic methanogens.

  11. Electro-Fenton pretreatment for the improvement of tylosin biodegradability.

    Science.gov (United States)

    Ferrag-Siagh, Fatiha; Fourcade, Florence; Soutrel, Isabelle; Aït-Amar, Hamid; Djelal, Hayet; Amrane, Abdeltif

    2014-01-01

    The feasibility of an electro-Fenton process to treat tylosin (TYL), a non-biodegradable antibiotic, was examined in a discontinuous electrochemical cell with divided cathodic and anodic compartments. Only 15 min electrolysis was needed for total tylosin degradation using a carbon felt cathode and a platinum anode; while 6 h electrolysis was needed to achieve high oxidation and mineralization yields, 96 and 88 % respectively. Biodegradability improvement was shown since BOD₅/COD increased from 0 initially to 0.6 after 6 h electrolysis (for 100 mg L(-1) initial TYL). With the aim of combining electro-Fenton with a biological treatment, an oxidation time in the range 2 to 4 h has been however considered. Results of AOS (average oxidation state) and COD/TOC suggested that the pretreatment could be stopped after 2 h rather than 4 h; while in the same time, the increase of biodegradability between 2 and 4 h suggested that this latter duration seemed more appropriate. In order to conclude, biological cultures have been therefore carried out for various electrolysis times. TYL solutions electrolyzed during 2 and 4 h were then treated with activated sludge during 25 days, showing 57 and 67% total organic carbon (TOC) removal, respectively, namely 77 and 88% overall TOC removal if both processes were considered. Activated sludge cultures appeared, therefore, in agreement with the assessment made from the analysis of physico-chemical parameters (AOS and COD/TOC), since the gain in terms of mineralization expected from increasing electrolysis duration appeared too low to balance the additional energy consumption.

  12. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  13. 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.

  14. A study of anaerobic biodegradation of pure homologue and isomers of linear alkylbenzene sulphonate (LAS) in batch digesters; Estudio de la biodegradacion anaerobia de homologos e isomeros puros de alquibenceno sulfonatos lineales (LAS) en digestores discontinuos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M. T.; Campos, E.; Illan, P.; Dalman, M.; Sanchez-Leal, J.

    2005-07-01

    In the present work the effect of different structural parameters on the anaerobic degradation of the LAS molecule has been studied. so, the effect both of the alkyl chain length and the phenyl position on the anaerobic degradation of the LAS molecule have been investigated. The behaviour of the individual homologues and isomers was studied applying discontinuous anaerobic tests (ECETOC-28). Sludge from the anaerobic digester of the waste water treatment plant of Manresa (Barcelona) was used as bacterial inoculum source. All the LAS homologues showed a poor primary biodegradation. In addition, no effect of the LAS isomer type was found on the anaerobic degradation kinetics. (Author) 6 refs.

  15. Biodegradation of industrial-strength 2,4-dichlorophenoxyacetic acid wastewaters in the presence of glucose in aerobic and anaerobic sequencing batch reactors.

    Science.gov (United States)

    Elefsiniotis, Panagiotis; Wareham, David G

    2013-01-01

    This research explored the biodegradability of 2,4-dichlorophenoxyacetic acid (2,4-D) in two laboratory-scale sequencing batch reactors (SBRs) that operated under aerobic and anaerobic conditions. The potential limit of 2,4-D degradation was investigated at a hydraulic retention time of 48 h, using glucose as a supplemental substrate and increasing feed concentrations of 2,4-D; namely 100 to 700 mg/L (i.e. industrial strength) for the aerobic system and 100 to 300 mg/L for the anaerobic SBR. The results revealed that 100 mg/L of 2,4-D was completely degraded following an acclimation period of 29 d (aerobic SBR) and 70 d (anaerobic SBR). The aerobic system achieved total 2,4-D removal at feed concentrations up to 600 mg/L which appeared to be a practical limit, since a further increase to 700 mg/L impaired glucose degradation while 2,4-D biodegradation was non-existent. In all cases, glucose was consumed before the onset of 2,4-D degradation. In the anaerobic SBR, 2,4-D degradation was limited to 120 mg/L.

  16. Mechanisms, Chemistry, and Kinetics of Anaerobic Biodegradation of cis-Dichloroethene and Vinyl Chloride

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, P.L.; Spormann, A.M.

    2000-12-01

    Anaerobic biological processes can result in PCE and TCE destruction through conversion to cis-dichloroethene (cDCE) then to vinyl chloride (VC), and finally to ethene. Here, the chlorinated aliphatic hydrocarbons (CAHs) serve as electron acceptors in energy metabolism, requiring electron donors such as hydrogen from an external source. The purpose of this study was to learn more about the biochemistry of cDCE and VC conversion to ethene, to better understand the requirements for electron donors, and to determine factors affecting the rates of CAH degradation and organism growth. The biochemistry of reductive dehalogenation of VC was studied with an anaerobic mixed culture enriched on VC. In other studies on electron donor needs for dehalogenation of cDCE and VC, competition for hydrogen was found to occur between the dehalogenators and other microorganisms such as methanogens and homoacetogens in a benzoate-acclimated dehalogenating methanogenic mixed culture. Factors affecting the relative rates of destruction of the solvents and their intermediate products were evaluated. Studies using a mixed PCE-dehalogenating culture as well as the VC enrichment for biochemical studies suggested that the same species was involved in both cDCE and VC dechlorination, and that cDCE and VC competitively inhibited each other's dechlorination rate.

  17. Chemical characterization and anaerobic biodegradability of hydrothermal liquefaction aqueous products from mixed-culture wastewater algae.

    Science.gov (United States)

    Tommaso, Giovana; Chen, Wan-Ting; Li, Peng; Schideman, Lance; Zhang, Yuanhui

    2015-02-01

    This study examined the chemical characteristics and the anaerobic degradability of the aqueous product from hydrothermal liquefaction (HTL-ap) from the conversion of mixed-culture algal biomass grown in a wastewater treatment system. The effects of the HTL reaction times from 0 to 1.5 h, and reaction temperatures from 260 °C to 320 °C on the anaerobic degradability of the HTL-ap were quantified using biomethane potential assays. Comparing chemical oxygen demand data for HTL-ap from different operating conditions, indicated that organic matter may partition from organic phase to aqueous phase at 320 °C. Moderate lag phase and the highest cumulative methane production were observed when HTL-ap was obtained at 320 °C. The longest lag phase and the smallest production rate were observed in the process fed with HTL-ap obtained at 300 °C. Nevertheless, after overcoming adaptation issues, this HTL-ap led to the second highest accumulated specific methane production. Acetogenesis was identified as a possible rate-limiting pathway.

  18. Biodegradation of azo dyes in a sequential anaerobic-aerobic system.

    Science.gov (United States)

    Rajaguru, P; Kalaiselvi, K; Palanivel, M; Subburam, V

    2000-08-01

    A sequential anaerobic aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent-contaminated soil was used to degrade sulfonated azo dyes Orange G (OG), Amido black 10B (AB), Direct red 4BS (DR) and Congo red (CR). Under anaerobic conditions in a fixed-bed column using glucose as co-substrate, the azo dyes were reduced and amines were released by the bacterial biomass. The amines were completely mineralized in a subsequent aerobic treatment using the same isolates. The maximum degradation rate observed in the treatment system for OG was 60.9 mg/l per day (16.99 mg/g glucose utilized), for AB 571.3 mg/l per day (14.46 mg/g glucose utilized), for DR 112.5 mg/l per day (32.02 mg/g glucose utilized) and for CR 134.9 mg/l per day (38.9 mg/g glucose utilized).

  19. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    Science.gov (United States)

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-02-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

  20. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    Science.gov (United States)

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-01-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal. PMID:28216654

  1. 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.

  2. Biodegradation kinetics during different start up of the anaerobic tapered fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    Rangasamy Parthiban

    2011-10-01

    Full Text Available Kinetic study for different start up conditions of the anaerobic digestion of wastewater derived from the sago processingfrom tubers of tapioca (Mannihot utillisema is discussed. The experiment is carried out with synthetic waste water usinga tapered fluidized bed reactor. Mesoporous granulated activated carbon is used as a bacterial support. The kinetic modelfollows half order kinetics for substrate utilization and for methane formation and it exhibits an order of 0.20 during thestart up of the reactor without acclimatization. For the remaining start up with acclimatized sludge, kinetic parameters areexpressed in terms of Langmuir-Hinshelwood kinetics for the substrate utilization. The methane formation kinetics followsan order of the reaction as 0.30. The values of the kinetic constants are in the range of 0.13–0.21.

  3. Anaerobic biodegradation of polylactic acid under mesophilic condition using thermal-alkaline pretreatment

    Science.gov (United States)

    Samitthiwetcharong, Sutisa; Kullavanijaya, Pratin; Chavalparit, Orathai

    2017-07-01

    The propose of this study was to investigate the effect of thermal-alkaline pretreatment with emphasis on sodium hydroxide concentration (NaOH), temperature and reaction time, on enhancement of polylactic acid (PLA) films degradation and biogas production. The results found that NaOH concentration and reaction time were two main parameters influencing on PLA degradation. While, less significant was found for temperature. From the Response Surface Methodology (RSM), it was concluded that the optimum pretreatment conditions were at 0.5 M of NaOH, temperature of 60°C and 24 hr of reaction time. This was generated about 3.7 times (215.47 ml/gVSadded) higher gas production comparing to non-pretreated PLA films which was 58.28 ml/gVSadded. The maximum biodegradability of PLA film was 20.14%. This was estimated to be 4.7 times higher than non-pretreated PLA (4.32%). This finding demonstrated the benefit of thermal-alkaline pretreatment on surface of PLA films destruction. Consequently, the microbial enzymes could degrade PLA more easily, resulting in an increase of biogas production.

  4. Thermal steam explosion pretreatment to enhance anaerobic biodegradability of the solid fraction of pig manure.

    Science.gov (United States)

    Ferreira, L C; Souza, T S O; Fdz-Polanco, F; Pérez-Elvira, S I

    2014-01-01

    The assessment of the biodegradability of thermal steam-exploded pig manure was performed compared to untreated samples. The pre-treatment was performed under different combinations of temperature and time, ranging 150-180 °C and 5-60 min, and used as substrate in a series of batch biochemical methane potential (BMP) tests. Results were analyzed in terms of methane yield, kinetic parameters and severity factor. In all the pre-treatment conditions, methane yield and degradation rates increased when compared to untreated pig slurry. An ANOVA study determined that temperature was the main factor, and the optimum combination of temperature-time of pretreatment was 170 °C -30 min, doubling methane production from 159 to 329 mL CH4/gVSfed. These operation conditions correspond to a severity factor of 3.54, which was considered an upper limit for the pretreatment due to the possible formation of inhibitory compounds, hindering the process if this limit is exceeded.

  5. Copper stressed anaerobic fermentation: biogas properties, process stability, biodegradation and enzyme responses.

    Science.gov (United States)

    Hao, He; Tian, Yonglan; Zhang, Huayong; Chai, Yang

    2017-07-15

    The effect of copper (added as CuCl2) on the anaerobic co-digestion of Phragmites straw and cow dung was studied in pilot experiments by investigating the biogas properties, process stability, substrate degradation and enzyme activities at different stages of mesophilic fermentation. The results showed that 30 and 100 mg/L Cu(2+) addition increased the cumulative biogas yields by up to 43.62 and 20.77% respectively, and brought forward the daily biogas yield peak, while 500 mg/L Cu(2+) addition inhibited biogas production. Meanwhile, the CH4 content in the 30 and 100 mg/L Cu(2+)-added groups was higher than that in the control group. Higher pH values (close to pH 7) and lower oxidation-reduction potential (ORP) values in the Cu(2+)-added groups after the 8th day indicated better process stability compared to the control group. In the presence of Cu(2+), the degradation of volatile fatty acids (VFAs) and other organic molecules (represented by chemical oxygen demand, COD) generated from hydrolysis was enhanced, and the ammonia nitrogen (NH4(+)-N) concentrations were more stable than in the control group. The contents of lignin and hemicellulose in the substrate declined in the Cu(2+)-added groups while the cellulose contents did not. Neither the cellulase nor the coenzyme F420 activities could determine the biogas producing efficiency. Taking the whole fermentation process into account, the promoting effect of Cu(2+) addition on biogas yields was mainly attributable to better process stability, the enhanced degradation of lignin and hemicellulose, the transformation of intermediates into VFA, and the generation of CH4 from VFA.

  6. Improvement of Landfill Leachate Biodegradability with Ultrasonic Process

    OpenAIRE

    Mahvi Amirhossein; Roodbari Aliakbar; Nabizadeh Nodehi Ramin; Naseri Simin; Dehghani Mohammadhadii; Alimohammadi Mahmood

    2012-01-01

    Leachate from mature landfills is typically characterized by high ammonium (NH4+) content, low biodegradability (low BOD5/COD ratio) and high fraction of refractory and large organic molecules such as humic and fulvic acids. Mature leachate effluents are known to contain recalcitrant and/or non-biodegradable organic substances and biological processes are not efficient in these cases. A promising alternative to complete oxidation of biorecalcitrant leachate is the use of ultrasonic process as...

  7. Response surface analysis to improve dispersed crude oil biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Zahed, Mohammad A.; Aziz, Hamidi A.; Mohajeri, Leila [School of Civil Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang (Malaysia); Isa, Mohamed H. [Civil Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia)

    2012-03-15

    In this research, the bioremediation of dispersed crude oil, based on the amount of nitrogen and phosphorus supplementation in the closed system, was optimized by the application of response surface methodology and central composite design. Correlation analysis of the mathematical-regression model demonstrated that a quadratic polynomial model could be used to optimize the hydrocarbon bioremediation (R{sup 2} = 0.9256). Statistical significance was checked by analysis of variance and residual analysis. Natural attenuation was removed by 22.1% of crude oil in 28 days. The highest removal on un-optimized condition of 68.1% were observed by using nitrogen of 20.00 mg/L and phosphorus of 2.00 mg/L in 28 days while optimization process exhibited a crude oil removal of 69.5% via nitrogen of 16.05 mg/L and phosphorus 1.34 mg/L in 27 days therefore optimization can improve biodegradation in shorter time with less nutrient consumption. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Biodegradation of high concentrations of phenol by baker’s yeast in anaerobic sequencing batch reactor

    Directory of Open Access Journals (Sweden)

    Ali Asghar Najafpoor

    2015-06-01

    Full Text Available Background: Phenol, as a pure substance, is used in many fields because of its disinfectant, germicidal, local anesthetic, and peptizing properties. Aqueous solutions of phenol are produced as waste in industries and discharged into the environment. Therefore, elevated concentrations of phenol may be found in air or water because of industrial discharge or the use of phenolic products. Method: The strains of Saccharomyces cerevisiae used in this project were natural strains previously purchased from Razavy company. They were grown at 30°C on Petri plates containing yeast extract glucose (YGC and then purified by being spread onto new plates, and isolated colonies were obtained. These colonies provided the basis of selection. Prepared strains were applied in anaerobic sequencing batch reactors (ASBRs as first seed. The experiment conditions were optimized using response surface methodology (RSM. After the determined runs were performed using Design-Expert software, data were analyzed using mentioned software as well. Results: This study evaluated the capability of baker’s yeast to remove phenol in high concentrations. The tested strains showed excellent tolerance to phenol toxicity at concentrations up to 6100 mg/L. Study of the batch degradation process showed that the phenol removal rate could exceed 99.9% in 24 hours at a concentration of 1000 mg/L. The results showed catechol is the first intermediate product of phenol degradation. In survey results of the Design–Expert software, R2 and Adeq precision were 0.97 and 25.65, respectively. Conclusion: The results demonstrated that ASBR performs robustly under variable influent concentrations of inhibitory compounds. The high removal performance despite the high phenol concentration may be a result of reactor operating strategies. Based on the progressive increase of inlet phenol concentration, allowing for an enhanced biomass acclimation in a short time, results at the microbiological levels

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

    Science.gov (United States)

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

    2014-10-01

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

  10. Heat treatment of organics for increasing anaerobic biodegradability. Annual progress report, June 1, 1976-May 31, 1977. Civil engineering technical report No. 222

    Energy Technology Data Exchange (ETDEWEB)

    Healy, J.B. Jr.; Owen, W.F.; Stuckey, D.C.; Young, L.Y.; McCarty, P.L.

    1977-06-30

    This report represents the results of the first year of study on the heat treatment of organics to increase its biodegradability by anaerobic bacteria for the microbial production of methane. The purpose of this study is to develop a means for increasing the yield and reducing the cost of methane, a useful energy source. The procedures being evaluated are heat treatment at temperatures up to 250/sup 0/C, under pH ranges of 1 to 13. Included in this report are results on: (1) lignocellulose digestion and acclimation to its products from heat treatment; (2) the fate of waste activated sludge and its cellular nitrogenous compounds; and (3) the biodegradability of model compounds likely to be formed during heat treatment.

  11. Screening and Identification of Two Anaerobic PAHs-biodegrading Strains%多环芳烃厌氧降解菌的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    刘珊垚; 吴涓; 王宁; 李玉成

    2011-01-01

    [目的]筛选并鉴定多环芳烃厌氧降解菌.[方法]通过富集,在厌氧条件下从受焦油长期污染的土壤中筛选出多环芳烃的高效厌氧降解菌,并对其进行了生理生化试验和16S rDNA鉴定.[结果]从受焦油长期污染的土壤中分离出2株多环芳烃降解菌W2和Y3,经综合表征和16S rDNA序列分析,初步鉴定菌株W2为鞘氨醇单胞菌属(Sphingomo sp.),菌株Y3为芽孢杆菌属(Bacillus sp.).[结论]为多环芳烃的生物降解研究提供了理论依据.%[ Objective] The aim was to screen and identify anaerobic PAHs-biodegrading strains. [ Method] High-efficient anaerobic PAHsbiodegrading strains ware screened out from the soil which was polluted by tar oil for a long time, and then carried out a physiological biochemical test and 16S rDNA identification. [ Result] Two anaerobic PAHs-biodegrading strains like W2 and Y3 were isolated from the soil which was polluted by tar oil for a long time. According to comprehensive characterization and 16S rDNA sequence analysis, W2 was preliminarily identified as Sphingomonas sp. , and Y3 was preliminarily identified as Bacillus sp.. [ Conclusion] The research provides theoretical basis for studies on PAHs biodegradation.

  12. Removal of nutrients from undiluted anaerobically treated piggery wastewater by improved microalgae.

    Science.gov (United States)

    Wang, Mingzi; Yang, Yi; Chen, Zhihong; Chen, Yanzhen; Wen, Yangmin; Chen, Bilian

    2016-12-01

    This study aimed at improving the adaptability and biodegradability of tested microalgae in undiluted anaerobic fermentation slurry of piggery wastewater. For that, a two-stage method based on UV irradiation followed by gradual domestication was developed. The distinctness of this method was the elimination of a screening procedure and just needed the UV-irradiated cells with appropriate survival to be subjected to gradual domestication. The microalgae treated with the method not only grew well in undiluted slurry, but achieved outstanding removal efficiencies in total nitrogen (TN) and total phosphorus (TP). Large-scale application was conducted in an open raceway pond, and the concentrations of TN and TP after treatment were 43.80mg/L (removal rate of 89.5%) and 5.83mg/L (removal rate of 85.3%) respectively, which greatly excelled the Chinese discharge standards for livestock and poultry wastewater. The strategy is therefore a promising method for microalgae to purify piggery slurry containing high nutrient contents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biodegradation and reversible inhibitory impact of sulfamethoxazole on the utilization of volatile fatty acids during anaerobic treatment of pharmaceutical industry wastewater.

    Science.gov (United States)

    Cetecioglu, Zeynep; Ince, Bahar; Gros, Meritxell; Rodriguez-Mozaz, Sara; Barceló, Damia; Ince, Orhan; Orhon, Derin

    2015-12-01

    This study evaluated the chronic impact and biodegradability of sulfamethoxazole under anaerobic conditions. For this purpose, a lab-scale anaerobic sequencing batch reactor was operated in a sequence of different phases with gradually increasing sulfamethoxazole doses of 1 to 45 mg/L. Conventional parameters, such as COD, VFA, and methane generation, were monitored with corresponding antimicrobial concentrations in the reactor and the methanogenic activity of the sludge. The results revealed that anaerobic treatment was suitable for pharmaceutical industry wastewater with concentrations of up to 40 mg/L of sulfamethoxazole. Higher levels exerted toxic effects on the microbial community under anaerobic conditions, causing the inhibition of substrate/COD utilization and biogas generation and leading to a total collapse of the reactor. The adverse long-term impact was quite variable for fermentative bacteria and methanogenic achaea fractions of the microbial community based on changes inflicted on the composition of the residual organic substrate and mRNA expression of the key enzymes.

  14. Improved Energy Recovery by Anaerobic Grey Water Sludge Treatment with Black Water

    NARCIS (Netherlands)

    Tervahauta, T.H.; Bryant, I.M.; Hernandez Leal, L.; Buisman, C.J.N.; Zeeman, G.

    2014-01-01

    This study presents the potential of combining anaerobic grey water sludge treatment with black water in an up-flow anaerobic sludge blanket (UASB) reactor to improve energy recovery within source-separated sanitation concepts. Black water and the mixture of black water and grey water sludge were co

  15. Prediction of anaerobic biodegradability and bioaccessibility of municipal sludge by coupling sequential extractions with fluorescence spectroscopy: towards ADM1 variables characterization.

    Science.gov (United States)

    Jimenez, Julie; Gonidec, Estelle; Cacho Rivero, Jesús Andrés; Latrille, Eric; Vedrenne, Fabien; Steyer, Jean-Philippe

    2014-03-01

    Advanced dynamic anaerobic digestion models, such as ADM1, require both detailed organic matter characterisation and intimate knowledge of the involved metabolic pathways. In the current study, a methodology for municipal sludge characterization is investigated to describe two key parameters: biodegradability and bioaccessibility of organic matter. The methodology is based on coupling sequential chemical extractions with 3D fluorescence spectroscopy. The use of increasingly strong solvents reveals different levels of organic matter accessibility and the spectroscopy measurement leads to a detailed characterisation of the organic matter. The results obtained from testing 52 municipal sludge samples (primary, secondary, digested and thermally treated) showed a successful correlation with sludge biodegradability and bioaccessibility. The two parameters, traditionally obtained through the biochemical methane potential (BMP) lab tests, are now obtain in only 5 days compared to the 30-60 days usually required. Experimental data, obtained from two different laboratory scale reactors, were used to validate the ADM1 model. The proposed approach showed a strong application potential for reactor design and advanced control of anaerobic digestion processes.

  16. Application of Simplified Anaerobic Digestion Models (SADM’s for Studying the Biodegradability and Kinetics of Cow Manure at Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Yusuf O.L. MOMOH

    2014-02-01

    Full Text Available The application of a set of simplified anaerobic digestion models (SADM’s to describe the anaerobic biodegradability and kinetics of cow manure at ambient temperature was conducted in this study. It was observed that the Hill’s based biogas yield rate model was the most appropriate in describing biogas yield rate from cow manure. Parameter estimation revealed that the half saturation constant expressed as acidified substrate and volatile solids (VS equivalent were 0.163g/l and 21.9g VS/l respectively while the maximum biogas yield rate was estimated to be 1.957ml/g VS/day. The coefficient of acidogenic bacteria adaptation (n and coefficient of acetogenic/methanogenic bacterial cooperativity (m were estimated to be 1.28 and 0.65 respectively. The poor cooperativity amongst the acetogenic/methanogenic bacterial species can be attributed to poor adaptation, possibly due to interaction between ammonia and volatile fatty acids. In addition, the biodegradability and recalcitrance was estimated to be 0.42 and 0.433 respectively, while hydrolysis/acidogenesis was identified as the rate limiting step.

  17. Biodegradation of azo dyes in cocultures of anaerobic granular sludge with aerobic aromatic amine degrading enrichment cultures

    NARCIS (Netherlands)

    Tan, N.C.G.; Prenefeta-Boldú, F.X.; Opsteeg, J.L.; Lettinga, G.; Field, J.A.

    1999-01-01

    A prerequisite for the mineralization (complete biodegradation) of many azo dyes is a combination of reductive and oxidative steps. In this study, the biodegradation of two azo dyes, 4-phenylazophenol (4-PAP) and Mordant Yellow 10 (4-sulfophenylazo-salicylic acid; MY10), was evaluated in batch exper

  18. Biodegradation of azo dyes in cocultures of anaerobic granular sludge with aerobic aromatic amine degrading enrichment cultures

    NARCIS (Netherlands)

    Tan, N.C.G.; Prenefeta-Boldú, F.X.; Opsteeg, J.L.; Lettinga, G.; Field, J.A.

    1999-01-01

    A prerequisite for the mineralization (complete biodegradation) of many azo dyes is a combination of reductive and oxidative steps. In this study, the biodegradation of two azo dyes, 4-phenylazophenol (4-PAP) and Mordant Yellow 10 (4-sulfophenylazo-salicylic acid; MY10), was evaluated in batch exper

  19. Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements

    Directory of Open Access Journals (Sweden)

    ChunMei Liu

    2015-01-01

    Full Text Available This research applied sodium hydroxide (NaOH pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L−1·d−1 of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%–62.2% higher than with NaOH-pretreatment alone and 22.2%–56.3% higher than with untreated corn stover. The best combination was obtained 5–9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production.

  20. Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements.

    Science.gov (United States)

    Liu, ChunMei; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Zhu, BaoNing; Li, XiuJin

    2015-01-01

    This research applied sodium hydroxide (NaOH) pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L(-1)·d(-1) of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%-62.2% higher than with NaOH-pretreatment alone and 22.2%-56.3% higher than with untreated corn stover. The best combination was obtained 5-9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production.

  1. Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements

    Science.gov (United States)

    Liu, ChunMei; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Zhu, BaoNing; Li, XiuJin

    2015-01-01

    This research applied sodium hydroxide (NaOH) pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L−1·d−1 of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%–62.2% higher than with NaOH-pretreatment alone and 22.2%–56.3% higher than with untreated corn stover. The best combination was obtained 5–9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production. PMID:26137469

  2. Impact of Anaerobic Phenanthrene Biodegradation on Bacterial and Archaeal Communities%菲厌氧降解对细菌和古细菌群落的影响

    Institute of Scientific and Technical Information of China (English)

    张书颖; 谢曙光

    2011-01-01

    利用TRFLP技术研究了受垃圾渗滤液污染的地下沉积物中细菌和古细菌群落在菲厌氧降解前后的变化。结果表明:细菌群落在生物降解过程中变化很大,物种丰度及Shannon-Weiner指数分别由15和2.39增加到23和2.88;古细菌群落在生物降解过程中变化较小,物种丰度及Shannon-Weiner指数变化不大。%Terminal restriction fragment length polymorphism(TRFLP) was used to investigate the change of bacterial and archaeal communities in leachate-contaminated aquifer in response to anaerobic phenanthrene biodegradation.Results show that a great change in bacterial community occurred with phenanthrene biodegradation.The ribotype and Shannon-Weiner index increase from 15 to 23,and 2.39 to 2.88 respectively.However,archaeal community only shows an insignificant change with phenanthrene biodegradation,and ribotype and Shannon-Weiner index vary slightly.

  3. The modification of microstructure to improve the biodegradation and mechanical properties of a biodegradable Mg alloy.

    Science.gov (United States)

    Han, Hyung-Seop; Minghui, Yin; Seok, Hyun-Kwang; Byun, Ji-Young; Cha, Pil-Ryung; Yang, Seok-Jo; Kim, Yu Chan

    2013-04-01

    The effect of microstructural modification on the degradation behavior and mechanical properties of Mg-5wt%Ca alloy was investigated to tailor the load bearing orthopedic biodegradable implant material. The eutectic Mg/Mg2Ca phase precipitated in the as-cast Mg-5wt%Ca alloy generated a well-connected network of Mg2Ca, which caused drastic corrosion due to a micro galvanic cell formed by its low corrosion potential. Breaking the network structure using an extrusion process remarkably retarded the degradation rate of the extruded Mg-5wt%Ca alloy, which demonstrates that the biocompatibility and mechanical properties of Mg alloys can be enhanced through modification of their microstructure. The results from the in vitro and in vivo study suggest that the tailored microstructure by extrusion impede the deterioration in strength that arises due to the dynamic degradation behavior in body solution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; M. Folmsbee; D. Nagle

    2004-05-31

    for anaerobic growth and biosurfactant production in DNA-supplemented Medium E. In addition to DNA or deoxyribonucleosides, nitrate, amino acids and vitamins were all required for anaerobic growth of JF-2. Bacillus mojavensisT (ABO21191), Bacillus mojavensis, strain ROB2 also required DNA or deoxyribonucleosides for anaerobic growth. The improved anaerobic growth of Bacillus mojavensis JF-2 was a prerequisite for studies that will lead to improved anaerobic biosurfactant production.

  5. Using natural zeolites to improve anaerobic abattoir wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Jimenez, L.; Herrera-Ramirez, E.; Carlos Hernandez, S

    2009-07-01

    Slaughterhouse wastewater have high concentrations of soluble and insoluble organics which represents environmental troubles, E. G. de oxygenation of rivers, underground water contamination. Anaerobic digestion is an efficient process for wastewater treatment. Performance are increased using microorganisms supported on porous solids. (Author)

  6. Biostimulation of anaerobic BTEX biodegradation under fermentative methanogenic conditions at source-zone groundwater contaminated with a biodiesel blend (B20).

    Science.gov (United States)

    Ramos, Débora Toledo; da Silva, Márcio Luis Busi; Chiaranda, Helen Simone; Alvarez, Pedro J J; Corseuil, Henry Xavier

    2013-06-01

    Field experiments were conducted to assess the potential for anaerobic biostimulation to enhance BTEX biodegradation under fermentative methanogenic conditions in groundwater impacted by a biodiesel blend (B20, consisting of 20 % v/v biodiesel and 80 % v/v diesel). B20 (100 L) was released at each of two plots through an area of 1 m(2) that was excavated down to the water table, 1.6 m below ground surface. One release was biostimulated with ammonium acetate, which was added weekly through injection wells near the source zone over 15 months. The other release was not biostimulated and served as a baseline control simulating natural attenuation. Ammonium acetate addition stimulated the development of strongly anaerobic conditions, as indicated by near-saturation methane concentrations. BTEX removal began within 8 months in the biostimulated source zone, but not in the natural attenuation control, where BTEX concentrations were still increasing (due to source dissolution) 2 years after the release. Phylogenetic analysis using quantitative PCR indicated an increase in concentration and relative abundance of Archaea (Crenarchaeota and Euryarchaeota), Geobacteraceae (Geobacter and Pelobacter spp.) and sulfate-reducing bacteria (Desulfovibrio, Desulfomicrobium, Desulfuromusa, and Desulfuromonas) in the biostimulated plot relative to the control. Apparently, biostimulation fortuitously enhanced the growth of putative anaerobic BTEX degraders and associated commensal microorganisms that consume acetate and H2, and enhance the thermodynamic feasibility of BTEX fermentation. This is the first field study to suggest that anaerobic-methanogenic biostimulation could enhance source zone bioremediation of groundwater aquifers impacted by biodiesel blends.

  7. Biodegradation of 2,3,7,8 TCDD by anaerobic and aerobic microcosms collected from bioremediation treatments for cleaning up dioxin contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Dang Thi; Tuan, Mai Anh; Viet, Nguyen Quoc; Sanh, Nguyen Thi [Vietnamese Academy of Science and Technology (VAST) (Viet Nam). Inst. of Biotechnology; Sau, Trinh Khac [Vietnam-Russian Tropical Center (Viet Nam); Papke, O. [ERGO Forschungsgesellschaft, Hamburg (Germany)

    2004-09-15

    There are many microbes that can degrade polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurants (PCDFs) and polychlorinated biphenyls (PCBs) have been isolated including purified bacteria, actinomycetes, white rods, filamentous fungi, anaerobes and also anaerobic and aerobic consortia. Bioremediation one of biological remediation has been studied as hopeful alternative to physical and chemical treatments that using for cleaning up PCDDs, PCDFs. In Vietnam for cleaning up ''hot spot'' of some former military air bases, bioremediation has been studying in different scales of Danang site. After 18 to 24 month treatments, the reduction of toxicity was significally detected. In order to study biodegradability by different groups and one of dominated strain that are existing microorganisms in our treatments, the investigation of 2,3,7,8 TCDD anaerobic and aerobic degradations was carried out in the laboratory condition. Anaerobic microbial consortium containing three different bacteria such as two Gram- negative vibrio and rod and one gram positive cocoides bacteria. This consortium could degrade 118 pg TEQ/ml 2,3,7,8 TCDD after 133 days under sulfate reduction. Concentration of 2,3,7,8 TCDD in the soil extract that adding to medium at starting point of cultivation was 144.6 pg TEQ/ml. About 81% toxicity was removed. Aerobic consortium containing all three Gram-negative bacteria and one fungal strain. After 9 day shaking at 180 rpm/min and 30 C, 85.6 % of 164.45 pg TEQ/ml 2,3,7,8 TCDD was removed. Other preliminary results of study of 2,3,7,8 TCDD biodegradation as sole carbon and energy by show that this strain FDN30 could remove 43,45 pg TEQ/ml (59%) of 73,1 pgTEQ/ml adding dioxin after two weeks. These findings explain why high concentration of contaminants in treated soil was decreased after two year treatment. Indigenous microorganisms play leading role in the detoxification of 2,3,7,8 TCDD in contaminated soils.

  8. Biodegradation of 2,3,7,8 TCDD by anaerobic and aerobic microcosms collected from bioremediation treatments for cleaning up dioxin contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Dang Thi; Tuan, Mai Anh; Viet, Nguyen Quoc; Sanh, Nguyen Thi [Vietnamese Academy of Science and Technology (VAST) (Viet Nam). Inst. of Biotechnology; Sau, Trinh Khac [Vietnam-Russian Tropical Center (Viet Nam); Papke, O. [ERGO Forschungsgesellschaft, Hamburg (Germany)

    2004-09-15

    There are many microbes that can degrade polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurants (PCDFs) and polychlorinated biphenyls (PCBs) have been isolated including purified bacteria, actinomycetes, white rods, filamentous fungi, anaerobes and also anaerobic and aerobic consortia. Bioremediation one of biological remediation has been studied as hopeful alternative to physical and chemical treatments that using for cleaning up PCDDs, PCDFs. In Vietnam for cleaning up ''hot spot'' of some former military air bases, bioremediation has been studying in different scales of Danang site. After 18 to 24 month treatments, the reduction of toxicity was significally detected. In order to study biodegradability by different groups and one of dominated strain that are existing microorganisms in our treatments, the investigation of 2,3,7,8 TCDD anaerobic and aerobic degradations was carried out in the laboratory condition. Anaerobic microbial consortium containing three different bacteria such as two Gram- negative vibrio and rod and one gram positive cocoides bacteria. This consortium could degrade 118 pg TEQ/ml 2,3,7,8 TCDD after 133 days under sulfate reduction. Concentration of 2,3,7,8 TCDD in the soil extract that adding to medium at starting point of cultivation was 144.6 pg TEQ/ml. About 81% toxicity was removed. Aerobic consortium containing all three Gram-negative bacteria and one fungal strain. After 9 day shaking at 180 rpm/min and 30 C, 85.6 % of 164.45 pg TEQ/ml 2,3,7,8 TCDD was removed. Other preliminary results of study of 2,3,7,8 TCDD biodegradation as sole carbon and energy by show that this strain FDN30 could remove 43,45 pg TEQ/ml (59%) of 73,1 pgTEQ/ml adding dioxin after two weeks. These findings explain why high concentration of contaminants in treated soil was decreased after two year treatment. Indigenous microorganisms play leading role in the detoxification of 2,3,7,8 TCDD in contaminated soils.

  9. ASSESSMENT OF OZONE AS A PRETREATMENT TO IMPROVE ANAEROBIC DIGESTION OF VINASSE

    Directory of Open Access Journals (Sweden)

    S. Aquino

    Full Text Available Abstract This paper presents an assessment of ozone oxidative effects on the biodegradability of sugar cane vinasse, aiming at increasing the methane yield by anaerobic digestion of this effluent. Furthermore, as a new approach, an economic balance of this process was made. Using a bench scale reactor, ozone was applied at 60, 120, 180, 240 mgO3.gCOD-1 doses in raw vinasse and at three initial pH values (4.8, 7 and 9. Applying 60 mgO3.gCOD-1, the biodegradability of vinasse was increased by 22.7% at the initial pH value of 4.8. The application of the two-way ANOVA test indicated a significant statistical interaction between the pH value and ozone. However, a preliminary energy assessment showed that the amount of electricity consumed in a full-scale ozonation plant would be almost 6 times higher than the energy recovered from the combustion of the additional methane produced (13.6%. These results indicate that ozonation of raw vinasse to increase the methane production in a subsequent anaerobic process is economically unfeasible.

  10. Improving the cyanide toxicity tolerance of anaerobic reactor: Microbial interactions and toxin reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Pragya; Ahammad, S.Z.; Sreekrishnan, T.R., E-mail: sree@iitd.ac.in

    2016-09-05

    Highlights: • Anaerobic batch study of 110 days. • Acclimatization for cyanide biodegradation. • Understanding inhibitory effects of cyanide on methane generation and VFA production. • Identification of microorganisms tolerant to cyanide. • Community analysis using DGGE and qPCR analyses. - Abstract: Anaerobic biological treatment of high organics containing wastewater is amongst the preferred treatment options but poor tolerance to toxins makes its use prohibitive. In this study, efforts have been made to understand the key parameters for developing anaerobic reactor, resilient to cyanide toxicity. A laboratory scale anaerobic batch reactor was set up to treat cyanide containing wastewater. The reactor was inoculated with anaerobic sludge obtained from a wastewater treatment plant and fresh cow dung in the ratio of 3:1. The focus was on acclimatization and development of cyanide-degrading biomass and to understand the toxic effects of cyanide on the dynamic equilibrium between various microbial groups. The sludge exposed to cyanide was found to have higher bacterial diversity than the control. It was observed that certain hydrogenotrophic methanogens and bacterial groups were able to grow and produce methane in the presence of cyanide. Also, it was found that hydrogen utilizing methanogens were more cyanide tolerant than acetate utilizing methanogens. So, effluents from various industries like electroplating, coke oven plant, petroleum refining, explosive manufacturing, and pesticides industries which are having high concentrations of cyanide can be treated by favoring the growth of the tolerant microbes in the reactors. It will provide much better treatment efficiency by overcoming the inhibitory effects of cyanide to certain extent.

  11. Distinct Dual C-Cl Isotope Fractionation Patterns during Anaerobic Biodegradation of 1,2-Dichloroethane: Potential To Characterize Microbial Degradation in the Field.

    Science.gov (United States)

    Palau, J; Yu, R; Hatijah Mortan, S; Shouakar-Stash, O; Rosell, M; Freedman, D L; Sbarbati, C; Fiorenza, S; Aravena, R; Marco-Urrea, E; Elsner, M; Soler, A; Hunkeler, D

    2017-03-07

    This study investigates, for the first time, dual C-Cl isotope fractionation during anaerobic biodegradation of 1,2-dichloroethane (1,2-DCA) via dihaloelimination by Dehalococcoides and Dehalogenimonas-containing enrichment cultures. Isotopic fractionation of 1,2-DCA (εbulk(C) and εbulk(Cl)) for Dehalococcoides (-33.0 ± 0.4‰ and -5.1 ± 0.1‰) and Dehalogenimonas-containing microcosms (-23 ± 2‰ and -12.0 ± 0.8‰) resulted in distinctly different dual element C-Cl isotope correlations (Λ = Δδ(13)C/Δδ(37)Cl ≈ εbulk(C)/εbulk(Cl)), 6.8 ± 0.2 and 1.89 ± 0.02, respectively. Determined isotope effects and detected products suggest that the difference on the obtained Λ values for biodihaloelimination could be associated with a different mode of concerted bond cleavage rather than two different reaction pathways (i.e., stepwise vs concerted). Λ values of 1,2-DCA were, for the first time, determined in two field sites under reducing conditions (2.1 ± 0.1 and 2.2 ± 2.9). They were similar to the one obtained for the Dehalogenimonas-containing microcosms (1.89 ± 0.02) and very different from those reported for aerobic degradation pathways in a previous laboratory study (7.6 ± 0.1 and 0.78 ± 0.03). Thus, this study illustrates the potential of a dual isotope analysis to differentiate between aerobic and anaerobic biodegradation pathways of 1,2-DCA in the field and suggests that this approach might also be used to characterize dihaloelimination of 1,2-DCA by different bacteria, which needs to be confirmed in future studies.

  12. Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Barenghi, R. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Farkas, B.; Romano, I. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scaglione, S. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Brandi, F. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, 56124-Pisa (Italy)

    2014-11-01

    The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation.

  13. The effect of salinity, redox mediators and temperature on anaerobic biodegradation of petroleum hydrocarbons in microbial fuel cells.

    Science.gov (United States)

    Adelaja, Oluwaseun; Keshavarz, Tajalli; Kyazze, Godfrey

    2015-01-01

    Microbial fuel cells (MFCs) need to be robust if they are to be applied in the field for bioremediation. This study investigated the effect of temperature (20-50°C), salinity (0.5-2.5% (w/v) as sodium chloride), the use of redox mediators (riboflavin and anthraquinone-2-sulphonate, AQS) and prolonged fed-batch operation (60 days) on biodegradation of a petroleum hydrocarbon mix (i.e. phenanthrene and benzene) in MFCs. The performance criteria were degradation efficiency, % COD removal and electrochemical performance. Good electrochemical and degradation performance were maintained up to a salinity of 1.5% (w/v) but deteriorated by 35-fold and 4-fold respectively as salinity was raised to 2.5%w/v. Degradation rates and maximum power density were both improved by approximately 2-fold at 40°C compared to MFC performance at 30°C but decreased sharply by 4-fold when operating temperature was raised to 50°C. The optimum reactor performance obtained at 40°C was 1.15 mW/m(2) maximum power density, 89.1% COD removal and a degradation efficiency of 97.10%; at moderately saline (1% w/v) conditions the maximum power density was 1.06 mW/m(2), 79.1% COD removal and 91.6% degradation efficiency. This work suggests the possible application of MFC technology in the effective treatment of petroleum hydrocarbons contaminated site and refinery effluents.

  14. [Study on biodegradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols].

    Science.gov (United States)

    Zhang, Wen; Chen, Ling; Ji, Jun-Ping; Xia, Si-Qing

    2007-06-01

    Purpose of this study was to determine the treatability of 2,4-dichlorophenol (2,4-DCP) by anaerobic granular sludge which was acclimated by mixed mono-chlorphenols (2-CP, 4-MCP). The characteristic of degradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols was investigated through shake flask study and performance of continuous flow anaerobic bioreactors. The difference of degradation of 2,4-DCP by acclimated and unacclimated sludge was also compared. 2,4-DCP was degraded at 50 h and 180 h respectively for acclimated and unacclimated sludge, which testified that acclimated sludge could more effectively degrade 2,4-DCP. Although the intermediate product 4-MCP was present in both reaction system, 4-MCP could be degraded completely after 400 h in the acclimated sludge but accumulated in the unacclimated sludge. Therefore, acclimation by the mixed mono-chlorphenols (2-CP, 4-MCP) could enhance the ability of para- and meta-dechlorination for anaerobic sludge and increase the treatability of 2,4-DCP. The results of continuous anaerobic sludge-suspended carrier bioreactor (ASSCB) indicate that inoculation of the acclimated sludge by mixed mono-chlorphenols can degrade two mono-chlorphenols simultaneously, shorten the setup period, and increase the efficiency of degrading 2,4-DCP. 2-CP was easily degraded with removal rate of over 80% . While the removal rate of 4-MCP was fluctuating within 30% - 80% with changes of its influent concentration.

  15. Back propagation neural network modelling of biodegradation and fermentative biohydrogen production using distillery wastewater in a hybrid upflow anaerobic sludge blanket reactor.

    Science.gov (United States)

    Sridevi, K; Sivaraman, E; Mullai, P

    2014-08-01

    In a hybrid upflow anaerobic sludge blanket (HUASB) reactor, biodegradation in association with biohydrogen production was studied using distillery wastewater as substrate. The experiments were carried out at ambient temperature (34±1°C) and acidophilic pH of 6.5 with constant hydraulic retention time (HRT) of 24h at various organic loading rates (OLRs) (1-10.2kgCODm(-3)d(-1)) in continuous mode. A maximum hydrogen production rate of 1300mLd(-1) was achieved. A back propagation neural network (BPNN) model with network topology of 4-20-1 using Levenberg-Marquardt (LM) algorithm was developed and validated. A total of 231 data points were studied to examine the performance of the HUASB reactor in acclimatisation and operation phase. The statistical qualities of BPNN models were significant due to the high correlation coefficient, R(2), and lower mean absolute error (MAE) between experimental and simulated data. From the results, it was concluded that BPNN modelling could be applied in HUASB reactor for predicting the biodegradation and biohydrogen production using distillery wastewater.

  16. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  17. Insights into the global regulation of anaerobic metabolism for improved biohydrogen production.

    Science.gov (United States)

    Lu, Yuan; Zhao, Hongxin; Zhang, Chong; Xing, Xin-Hui

    2016-01-01

    To improve the biohydrogen yield in bacterial dark fermentation, a new approach of global anaerobic regulation was introduced. Two cellular global regulators FNR and NarP were overexpressed in two model organisms: facultatively anaerobic Enterobacter aerogenes (Ea) and strictly anaerobic Clostridium paraputrificum (Cp). The overexpression of FNR and NarP greatly altered anaerobic metabolism and increased the hydrogen yield by 40%. Metabolic analysis showed that the global regulation caused more reducing environment inside the cell. To get a thorough understanding of the global metabolic regulation, more genes (fdhF, fhlA, ppk, Cb-fdh1, and Sc-fdh1) were overexpressed in different Ea and Cp mutants. For the first time, it demonstrated that there were approximately linear relationships between the relative change of hydrogen yield and the relative change of NADH yield or ATP yield. It implied that cellular reducing power and energy level played vital roles in the biohydrogen production.

  18. Environmentally Relevant Inoculum Concentrations Improve the Reliability of Persistent Assessments in Biodegradation Screening Tests.

    Science.gov (United States)

    Martin, Timothy J; Snape, Jason R; Bartram, Abigail; Robson, Aidan; Acharya, Kishor; Davenport, Russell J

    2017-02-23

    Standard OECD biodegradation screening tests (BSTs) have not evolved at the same rate as regulatory concerns, which now place an increased emphasis on environmental persistence. Consequently, many chemicals are falsely assigned as being potentially persistent based on results from BSTs. The present study increased test duration and increased inoculum concentrations to more environmentally relevant levels to assess their impact on biodegradation outcome and intratest replicate variability for chemicals with known environmental persistence. Chemicals were assigned to potential persistence categories based on existing degradation data. These more environmentally relevant BSTs (erBSTs) improved the reliability of persistence assignment by reducing the high variability associated with these tests and the occurrence of failures at low inoculum concentrations due to the exclusion of specific degraders. Environmental fate was determined using a reference set of (14)C-labeled compounds with a range of potential environmental persistences, and full mass balance data were collated. The erBST correctly assigned five reference chemicals of known biodegradabilities to their appropriate persistence category in contrast to a standard OECD Ready Biodegradation Test (RBTs, P < 0.05). The erBST was significantly more reproducible than an OECD RBT (ANOVA, P < 0.05), with more consistent rates and extent of biodegradation observed in the erBST.

  19. Improved biodegradation of textile dye effluent by coculture.

    Science.gov (United States)

    Vijayalakshmidevi, S R; Muthukumar, Karuppan

    2015-04-01

    The present study demonstrates the de-colorization and degradation of textile effluent by coculture consisting of three bacterial species isolated from textile effluent contaminated environment with an aim to reduce the treatment time. The isolates were identified as Ochrobactrum sp., Pseudomonas aeruginosa and Providencia vermicola by 16S rRNA analysis. Their secondary structure was predicted and GC content of the sequence was found to be 54.39, 52.10, and 52.53%. The co-culture showed a prominent increase in the degradation activity due to the action of oxidoreductase enzymatic mechanism of laccase, NADH-DCIP reductase and azoreductase activity. The biodegradability index of 0.75 was achieved with 95% chemical oxygen demand (COD) reduction in 16 h and 78 and 85% reduction in total organic carbon (TOC) and total solids was observed. Bioaccumulation of metals was identified by X-ray diffraction (XRD) analysis. The effective decolorization was confirmed from the results of UV-vis spectroscopy, high performance liquid chromatography and Fourier transformed infrared spectrometer analyzes. The possible degradation pathway was obtained from the analysis of liquid chromatography-mass spectroscopy analysis and the metabolites such as 2-amino naphthalene and N-phenyl-1.3,5 triazine were observed. The toxic nature of the effluent was analyzed using phyto-toxicity, cell-death assay and geno-toxicity tests.

  20. Contribution of quinone-reducing microorganisms to the anaerobic biodegradation of organic compounds under different redox conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, F. J.; Gutierrez, C. H.; Lopez, K. Y.; Estrada-Alvarodo, M. I.; Meza-Escalante, E. R.; Texier, A. C.; Cuervo, F.; Gomez, J.

    2009-07-01

    Reduction of humic substances (HS) has recently been recognized as a microbial respiratory process supporting growth of several distinct microorganisms. Quinone moieties, which are very abundant in the humic acid fraction of humus, are the main functional groups conferring electron-accepting capacity to HS. The capacity to reduce HS has been reported in anaerobic consortia from a wide diversity of environments. (Author)

  1. 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.

  2. Anaerobic Biodegradation of Microcystin by Bacterial Community from Sediment of Dianchi Lake%滇池沉积物菌群对微囊藻毒素的厌氧生物降解

    Institute of Scientific and Technical Information of China (English)

    陈晓国; 杨霞; 陈锦; 张圣虎; 肖邦定

    2009-01-01

    好氧微生物降解已经被证明是微囊藻毒素(MC)自然转化的主要途径,但是厌氧降解的作用尚不明确.为了揭示这一降解过程,研究了滇池沉积物中混合菌群在厌氧条件下对MCLR的降解能力,并考察了环境因素和外加营养源对该过程的影响.结果表明,厌氧条件下MCLR在2 d内从5 mg/L迅速降解到检测限以下,说明该菌群在厌氧条件下对MCLR具有较强的降解能力,并且可以利用MCLR作为唯一氮源.在实验温度范围内,MCLR的降解速率随着温度的升高而增大.酸性条件下MCLR的厌氧降解缓慢(pH=5.0)甚至停止(pH=3.0),而中性(pH=7.0)和碱性(pH为9.0、11.0)条件下降解速率没有显著差异.单独添加葡萄糖可以产生酸性物质而使体系的pH下降,从而抑制MCLR的降解,但是同时添加硝酸盐可以消除这一影响.单独添加硝酸盐对MCLR的厌氧降解也有显著的抑制作用,说明硝酸根在这一过程中未被MCLR厌氧降解菌用作最终电子受体.以上结果表明,厌氧降解可能是沉积物中MCLR转化的另一重要途径,该过程在MCLR污染治理方面具有潜在的应用价值.%Aerobic biodegradation has been identified as the main attenuation mechanism for microcystin, but the role of anaerobic microcystin biodegradation remains unclear. To elucidate this process, we assessed the potential for anaerobic microcystin LR biodegradation by sediment microbial community from Dianchi Lake and evaluated the effects of environmental factors and additional nutrient sources on the rates of anaerobic biodegradation. The results showed that microcystin LR was rapidly degraded from 5 mg/L to below detection limit within 2 days, demonstrating that the indigenous microorganisms can efficiently degrade microcystin LR under anaerobic conditions and can use microcystin LR as a sole nitrogen source. The rates of anaerobic microcystin LR biodegradation increased with increasing incubation temperature within the

  3. Anaerobic biodegradation of 13C6-phenol: Analysis of bacteria population involved in two different degradation kinetics

    OpenAIRE

    Hoyos Hernandez, C.; Limam, I.; Desmond, E.; Bouchez, T.; Mazeas, L.

    2013-01-01

    International audience; Biodegradation of 13C6-phenol until mineralisation was observed under mesophilic and thermophilic conditions during the degradation of municipal solid waste. In Mesophilic conditions, as well as in thermophilic, two types of degradation kinetics were obtained. One follows a first order kinetic and the other follows a lag-phase model. The pyrosequencing analysis shows that in the fastest kinetic Clostridium sp. and Anaerobranca sp. were the microorganisms majorly presen...

  4. Anaerobic fermentation of agricultural residue: potential for improvement and implementation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, W. J.; Capener, H. R.; Dell& #x27; orto, S.

    1978-02-01

    The results of studies designed to evaluate the potential of rapidly improving the technology of anaerobic fermentation of agricultural residues and methods of implementing it in existing agricultural operations are reported. The main objectives of this study were to: identify simple and low cost anaerobic fermentor design criteria that would be appropriate in small agricultural operations, develop high rate fermentor concepts that would enable multiple product recovery from the reactor, expand the information base particularly in the area of temperature influence on the process, and to review sociological and economic issues relating to implementation of fermentation technology. This study has identified several major anaerobic fermentation concepts which illustrate that the technology may be rapidly improved. A simple reactor design utilizing an unmixed plug flow concept was shown to be comparable to the more complex completely mixed reactor when using dairy cow residue. A high rate thermophilic reactor designed to encourage flotation of particulate solids illustrated that liquid, solid, and gaseous products can be generated within the anaerobic fermentor thus eliminating an additional dewatering unit process. A third reactor concept involved extension of the anaerobic attached microbial film expanded bed to the treatment of cow manure slurries. A high rate of methane generation was recorded. Comprehensive thermophilic fermentation studies (60/sup 0/C) indicated that the increased temperature resulted in little improvement in total quantity or the rate of yield of gas over that obtained with mesophilic fermentation with reactor retention periods greater than 10 days. Finally, other areas where preliminary date were obtained are noted.

  5. Mesophilic and thermophilic activated sludge post treatment of anaerobic effluent : sludge and wastewater characterization using batch experiments

    NARCIS (Netherlands)

    Vogelaar, J.C.T.; Klapwijk, A.; Lier, van J.B.; Lettinga, G.

    2002-01-01

    Anaerobic pretreated paper process water was characterized in terms of readily biodegradable, slowly biodegradable, very slowly biodegradable and inert wastewater fractions under mesophilic and thermophilic conditions. The anaerobic pretreated paper process water contained a relatively high amount o

  6. Anaerobic biodegradation of longer-chain n-alkanes coupled to methane production in oil sands tailings.

    Science.gov (United States)

    Siddique, Tariq; Penner, Tara; Semple, Kathleen; Foght, Julia M

    2011-07-01

    Extraction of bitumen from mined oil sands ores produces enormous volumes of tailings that are stored in settling basins (current inventory ≥ 840 million m(3)). Our previous studies revealed that certain hydrocarbons (short-chain n-alkanes [C(6)-C(10)] and monoaromatics [toluene, o-xylene, m-xylene]) in residual naphtha entrained in the tailings are biodegraded to CH(4) by a consortium of microorganisms. Here we show that higher molecular weight n-alkanes (C(14), C(16), and C(18)) are also degraded under methanogenic conditions in oil sands tailings, albeit after a lengthy lag (~180 d) before the onset of methanogenesis. Gas chromatographic analyses showed that the longer-chain n-alkanes each added at ~400 mg L(-1) were completely degraded by the resident microorganisms within ~440 d at ~20 °C. 16S rRNA gene sequence analysis of clone libraries implied that the predominant pathway of longer-chain n-alkane metabolism in tailings is through syntrophic oxidation of n-alkanes coupled with CO(2) reduction to CH(4). These studies demonstrating methanogenic biodegradation of longer-chain n-alkanes by microbes native to oil sands tailings may be important for effective management of tailings and greenhouse gas emissions from tailings ponds.

  7. Anaerobic biodegradation of oleic and palmitic acids: evidence of mass transfer limitations caused by long chain fatty acid accumulation onto the anaerobic sludge.

    Science.gov (United States)

    Pereira, M A; Pires, O C; Mota, M; Alves, M M

    2005-10-05

    Palmitic acid was the main long chain fatty acids (LCFA) that accumulated onto the anaerobic sludge when oleic acid was fed to an EGSB reactor. The conversion between oleic and palmitic acid was linked to the biological activity. When palmitic acid was fed to an EGSB reactor it represented also the main LCFA that accumulated onto the sludge. The way of palmitic acid accumulation was different in the oleic and in the palmitic acid fed reactors. When oleic acid was fed, the biomass-associated LCFA (83% as palmitic acid) were mainly adsorbed and entrapped in the sludge that became "encapsulated" by an LCFA layer. However, when palmitic acid was fed, the biomass-associated LCFA (the totality as palmitic acid) was mainly precipitated in white spots like precipitates in between the sludge, which remained "non-encapsulated." The two sludges were compared in terms of the specific methanogenic activity (SMA) in the presence of acetate, propionate, butyrate, and H(2)CO(2), before and after the mineralization of similar amounts of biomass-associated LCFA (4.6 and 5.2 g COD-LCFA/g of volatile suspended solids (VSS), for the oleic and palmitic acid fed sludge, respectively). The "non-encapsulated," sludge exhibited a considerable initial methanogenic activity on all the tested substrates, with the single exception of butyrate. However, with the "encapsulated" sludge only methane production from ethanol and H(2)/CO(2) was detected, after a lag phase of about 50 h. After mineralization of the biomass-associated LCFA, both sludges exhibited activities of similar order of magnitude in the presence of the same individual substrates and significantly higher than before. The results evidenced that LCFA accumulation onto the sludge can create a physical barrier and hinder the transfer of substrates and products, inducing a delay on the initial methane production. Whatever the mechanism, metabolic or physical, that is behind this inhibition, it is reversible, being eliminated after the

  8. Can the anaerobic potentially mineralizable nitrogen test improve predictions of fertilizer nitrogen rates in the Cornbelt?

    Science.gov (United States)

    Correctly estimating the amount of mineralizable nitrogen (N) can enhance nitrogen use efficiency. The anaerobic potentially mineralizable nitrogen (PMNAn) test is a tool that may help improve predictions of N uptake, grain yield, and the economical optimum nitrogen rate (EONR) of corn (Zea mays L...

  9. Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

    Science.gov (United States)

    Zhang, Yang; Piccard, Sarah; Zhou, Wen

    2015-11-01

    The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus.

  10. Different strategies to improve the functionality of biodegradable films based on starch and other polymers

    OpenAIRE

    2016-01-01

    [EN] In the present Doctoral Thesis, different strategies to improve functional properties of starch films for food packaging applications were analysed: study of the effect of amylose:amylopectin ratio, blend with other polymers poly(vinyl alcohol) (PVA), and incorporation of different fillers (rice bran and cellulose nanocrystals-CNCs) and antimicrobial agents (neem oil-N, oregano essential oil-O and silver nanoparticles-AgNPs). Likewise, a biodegradation study of the films as affected by a...

  11. Effect of thermal treatment of anaerobic sludge on the bioavailability and biodegradability characteristics of the organic fraction

    Directory of Open Access Journals (Sweden)

    E. S. M. Borges

    2009-09-01

    Full Text Available Most works reported in the literature focus on thermal treatment of waste activated sludge at temperatures in the range of 160 to 180ºC. This research aimed at evaluating the thermal treatment of excess anaerobic sludge at much lower temperatures, using biogas generated in the wastewater treatment process as the energy source for heating a simplified thermal reactor. Direct burning of the biogas allowed an increase in the sludge temperature up to values close to 75ºC, for a 7-hour heating period. Sludge samples taken at different heating times showed that the thermal disintegration of the organic fraction allowed increases in the concentration of protein, carbohydrate, lipid and COD parameters by 30 to 35 times, as well as a 50% increase in the biogas production. Moreover, the simplified thermal treatment system proved to be an effective alternative for recovering energy from biogas and for controlling methane emissions to the atmosphere.

  12. Potential for anaerobic conversion of xenobiotics

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank

    2003-01-01

    This review covers the latest research on the anaerobic biodegradation of aromatic xenobiotic compounds, with emphasis on surfactants, polycyclic aromatic hydrocarbons, phthalate esters, polychlorinated biphenyls, halogenated phenols, and pesticides. The versatility of anaerobic reactor systems...

  13. Improve the Anaerobic Biodegradability by Copretreatment of Thermal Alkali and Steam Explosion of Lignocellulosic Waste

    National Research Council Canada - National Science Library

    Siddhu, Muhammad Abdul Hanan; Li, Jianghao; Zhang, Jiafu; Huang, Yan; Wang, Wen; Chen, Chang; Liu, Guangqing

    2016-01-01

      Effective alteration of the recalcitrance properties like crystallization of cellulose, lignin shield, and interlinking of lignocellulosic biomass is an ideal way to utilize the full-scale potential...

  14. 白假丝酵母PDY-07厌氧生物降解4-氯酚的研究%Biodegradation of 4-Chlorophenol by Candida albicans PDY-07 under Anaerobic Conditions

    Institute of Scientific and Technical Information of China (English)

    闻建平; 李红梅; 白静; 姜岩

    2006-01-01

    Candida albicans PDY-07 was isolated from activated sludge under anaerobic conditions and identified as a member belonging to the genus Candida. Pure culture of C. albicans PDY-07, biodegradation of 4-chlorophenol (4-CP) was carried out under anaerobic conditions in Erlenmeyer flasks at 35 ℃, with an initial pH of 7.0-7.2 and a starting inoculum of 10% (by volume). The results showed that, under the above-mentioned conditions, C. albicans PDY-07 could thoroughly biodegrade 4-CP up to a concentration of 300 mg·L-1 within 244h and that it had a high tolerance potential of up to 440 mg·L-1 for 4-CP. With the increase in the initial concentrations of 4-CP, substrate inhibition was obviously enhanced. There was increased consumption of 4-CP, which was not assimilated by the cell for growth but was used to counteract the strong substrate inhibition. In addition, the cell growth and substrate-degradation kinetics of 4-CP as the sole source of carbon and energy for the strain in batch cultures were also investigated over a wide range of substrate concentrations (2.2-350 mg·L-1), using the proposed cell growth and degradation kinetic models. The results recorded from these experiments showed that the proposed kinetic models adequately described the dynamic behavior of 4-CP biodegradation by C. albicans PDY-07.

  15. Effect of test concentration in the ready biodegradability test for chemical substances: Improvement of OECD test guideline 301C.

    Science.gov (United States)

    Nabeoka, Ryosuke; Taruki, Masanori; Kayashima, Takakazu; Yoshida, Tomohiko; Kameya, Takashi

    2016-01-01

    In Japan, understanding the environmental persistence of chemicals is very important for risk assessment, and ready biodegradability tests are mainly conducted according to the Organisation for Economic Co-operation and Development test guideline 301C. However, the highest test concentration specified in test guideline 301C, 100 mg/L, may cause microbial toxicity and incomplete biodegradation. The authors performed test guideline 301C tests at test concentrations of 30 mg/L for 13 substances that were readily biodegradable in ready biodegradability tests but not in test guideline 301C tests. Of the 5 substances with potential to cause microbial toxicity at 100 mg/L, the percentage of biodegradation of sodium dimethyldithiocarbamate, 4-chloro-3-cresol (CC), thymol (THY), and p-tert-butyl-α-methylbenzenepropionaldehyde measured by biochemical oxygen demand (BOD) increased in the test guideline 301C test at 30 mg/L, suggesting a reduction in toxicity effects. Furthermore, CC and THY met the criteria for ready biodegradability, which are more than 60% of biodegradation by BOD and a 10-d window. Of the 8 substances with a low potential for causing microbial toxicity at 100 mg/L, the percentage of biodegradation of only 2-(diethylamino)ethanol increased in the test guideline 301C test at 30 mg/L. Employing a lower test concentration in the standard test guideline 301C test will contribute to improvement of consistency between results of a test guideline 301C test and other ready biodegradability tests. © 2015 SETAC.

  16. Improved Energy Recovery by Anaerobic Grey Water Sludge Treatment with Black Water

    Directory of Open Access Journals (Sweden)

    Taina Tervahauta

    2014-08-01

    Full Text Available This study presents the potential of combining anaerobic grey water sludge treatment with black water in an up-flow anaerobic sludge blanket (UASB reactor to improve energy recovery within source-separated sanitation concepts. Black water and the mixture of black water and grey water sludge were compared in terms of biochemical methane potential (BMP, UASB reactor performance, chemical oxygen demand (COD mass balance and methanization. Grey water sludge treatment with black water increased the energy recovery by 23% in the UASB reactor compared to black water treatment. The increase in the energy recovery can cover the increased heat demand of the UASB reactor and the electricity demand of the grey water bioflocculation system with a surplus of 0.7 kWh/cap/y electricity and 14 MJ/cap/y heat. However, grey water sludge introduced more heavy metals in the excess sludge of the UASB reactor and might therefore hinder its soil application.

  17. Phthalates biodegradation in the environment.

    Science.gov (United States)

    Liang, Da-Wei; Zhang, Tong; Fang, Herbert H P; He, Jianzhong

    2008-08-01

    Phthalates are synthesized in massive amounts to produce various plastics and have become widespread in environments following their release as a result of extensive usage and production. This has been of an environmental concern because phthalates are hepatotoxic, teratogenic, and carcinogenic by nature. Numerous studies indicated that phthalates can be degraded by bacteria and fungi under aerobic, anoxic, and anaerobic conditions. This paper gives a review on the biodegradation of phthalates and includes the following aspects: (1) the relationship between the chemical structure of phthalates and their biodegradability, (2) the biodegradation of phthalates by pure/mixed cultures, (3) the biodegradation of phthalates under various environments, and (4) the biodegradation pathways of phthalates.

  18. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    Science.gov (United States)

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure.

  19. Cold Oxygen Plasma Treatments for the Improvement of the Physicochemical and Biodegradable Properties of Polylactic Acid Films for Food Packaging.

    Science.gov (United States)

    Song, Ah Young; Oh, Yoon Ah; Roh, Si Hyeon; Kim, Ji Hyeon; Min, Sea C

    2016-01-01

    The effects of cold plasma (CP) treatment on the physicochemical and biodegradable properties of polylactic acid (PLA) films were studied. The PLA films were exposed to CP for 40 min at 900 W and 667 Pa using oxygen as the plasma-forming gas. The tensile, optical, and dynamic mechanical thermal properties, surface morphology, printability, water contact angle, chemical structure, weight change, and biodegradability properties of the films were evaluated during storage for up to 56 d. The tensile and optical properties of the PLA films were not significantly affected by CP treatment (CPT; P > 0.05). The surface roughness and water contact angle of PLA films increased by CPT and further increased during storage for 56 d. The printability of the PLA films increased following CPT and remained stable throughout the storage period. CP-induced hydrophilicity was also sustained during the storage period. The PLA films lost 1.9% of their weight after CPT, but recovered 99.5% of this loss after 14 d in storage. Photodegradation, thermal, and microbial biodegradable properties of the films were significantly improved by CPT (P < 0.05). Accelerated biodegradation of CP-treated PLA sachets with and without cheese was observed in compost. These results demonstrate the potential of CPT for modifying the stiffness, water contact angle, and chemical structure of PLA films and improving the printability and biodegradability of the films for food packaging.

  20. Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation

    Directory of Open Access Journals (Sweden)

    Khorasani Alireza Chackoshian

    2013-01-01

    Full Text Available Abstract Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models.

  1. Study on Biodegradation of Mazut by Newly Isolated strain Enterobacter Cloacae BBRC10061: Improving and Kinetic Investigation

    Directory of Open Access Journals (Sweden)

    Alireza Chackoshian Khorasan

    2013-01-01

    Full Text Available Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models.

  2. On improving effect combining aerobic and anaerobic loads of character in the classroom for physical training in universities

    Directory of Open Access Journals (Sweden)

    Goginava S.E.

    2014-06-01

    Full Text Available Purpose: substantiate the health effects on the body through a combination of students in the classroom for physical training loads of aerobic and anaerobic nature. Material : the study involved 174 students of 1-3 courses NIU "BSU." Of these, 90 girls and 84 boys aged 17-20 years. Results : the specificity of the health effects of athletic gymnastics as a means of anaerobic training students. The specificity of the health effects of swimming as a means of improving aerobic exercise. Expediency and the method of load combination of aerobic and anaerobic focus on employment in physical education with students. Conclusions: results of scientific studies show that the load combination of aerobic and anaerobic characters on physical education classes at the university promotes the significant increase in the level of physical health of students of the basic training department.

  3. Improving the miscibility of biodegradable polyester/polyphosphazene blends using cross-linkable polyphosphazene.

    Science.gov (United States)

    Shan, Dingying; Huang, Zhaohui; Zhao, Yuchen; Cai, Qing; Yang, Xiaoping

    2014-11-26

    Biodegradable polyesters and polyphosphazenes are both promising biomaterials for tissue regeneration. A combination of both materials would provide additional advantages over the individual components in aspects of biocompatibility and osteocompatibility. Applications of polyester/polyphosphazene composites, however, were limited due to the severe phase separation. In this study, cross-linkable poly(glycine ethyl ester-co-hydroxyethyl methacrylate)phosphazene (PGHP) was synthesized. It was blended with poly(L-lactide) (PLLA) or poly(L-lactide-co-glycolide) (PLGA), using chloroform as a mutual solvent, and photo-crosslinked before solvent removal. The resulting PLLA (or PLGA)/PGHP composites demonstrated no significant phase separation due to the restricting function of the crosslinked PGHP polymeric network. In comparison with uncrosslinked blends, the mechanical properties of crosslinked composites were remarkably improved, which indicated their strong potential in bone regeneration applications.

  4. Evaluation of anaerobic sludge volume for improving azo dye decolorization in a hybrid anaerobic reactor with built-in bioelectrochemical system.

    Science.gov (United States)

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Wang, Ai-Jie; Cheng, Hao-Yi

    2017-02-01

    A hybrid anaerobic reactor with built-in bioelectrochemical system (BES) has been verified for efficiently treating mixed azo dye wastewater, yet still facing many challenges, such as uncertain reactor construction and insufficient electron donors. In this study, an up-flow hybrid anaerobic reactor with built-in BES was developed for acid orange 7 (AO7) containing wastewater treatment. Cathode and real domestic wastewater both served as electron donor for driving azo dye decolorization. The decolorization efficiency (DE) of AO7 (200 mg/L) in the hybrid reactor was 80.34 ± 2.11% with volume ratio between anaerobic sludge and cathode (VRslu:cat) of 0.5:1 and hydraulic retention time (HRT) of 6 h, which was 15.79% higher than that in BES without sludge zone. DE was improved to 86.02 ± 1.49% with VRslu:cat increased to 1:1. Further increase in the VRslu:cat to 1.5:1 and 2:1, chemical oxygen demand (COD) removal efficiency was continuously improved to 28.78 ± 1.96 and 32.19 ± 0.62%, but there was no obvious DE elevation (slightly increased to 87.62 ± 2.50 and 90.13 ± 3.10%). BES presented efficient electron utilization, the electron usage ratios (EURs) in which fluctuated between 11.02 and 13.06 mol e(-)/mol AO7. It was less than half of that in sludge zone of 24.73-32.06 mol e(-)/mol AO7. The present work optimized the volume ratio between anaerobic sludge and cathode that would be meaningful for the practical application of this hybrid system.

  5. Improvements of physical, mechanical and biodegradation properties of polybutadiene rubber insulators by chitosan and silica nanoparticles.

    Science.gov (United States)

    Saboktakin, Amin; Saboktakin, Mohammadreza

    2016-10-01

    1,4-cis-Polybutadiene rubber(1,4-cis pBR) as an insulation material is developing that will provide superior thermal insulation properties, flexibility, toughness by natural polymers such as chitosan(CS) and silica nanoparticles. This material is widely used in the insulation industries specially architecture. This research concerns physical, mechanical properties and also biodegradation of 1,4-cis pBR, which to be composed with the natural polymers such as CS. Silica nanoparticles were used as filler to improve the physical and mechanical properties of 1,4-cis pBR. To evaluating its physical and mechanical properties, stretching and bending and impact tests were used and the results show some improvement in these properties. Our observations show that temperature plays an important role as main factor in order to improve the mechanical properties of nanocomposites. Similar improvements in tensile modulus and strength have been observed for 1,4-cis pBR/CS-silica nanoparticles.

  6. Improving the energy balance of grass-based anaerobic digestion through combined harvesting and pretreatment

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Egelund, H.

    2017-01-01

    An important challenge that has to be addressed to achieve sustainable anaerobic digestion of lignocellulosic substrates is the development of energy and cost efficient pretreatment methods. Technologies orientated to simultaneously harvest and mechanically pretreat the biomass at the field could...... meet these criteria as they can potentially reduce the energy losses. The objective of this study was to elucidate the effect of two full-scale harvesting machines to enhance the biogas production and subsequently, improve energy balance. The performances of Disc-mower and Excoriator were assessed...... technology. More specifically, Excoriator, which cuts and subsequently applies shearing forces on harvested biomass, enhanced the methane production up to 10% and the overall energy budget was improved proportionally to the driving speed increase....

  7. Intermittent hypoxic training improves anaerobic performance in competitive swimmers when implemented into a direct competition mesocycle

    Science.gov (United States)

    Wilk, Robert; Karpiński, Jakub; Chalimoniuk, Małgorzata; Zajac, Adam; Langfort, Józef

    2017-01-01

    The main objective of this research was to evaluate the efficacy of intermittent hypoxic training (IHT) on anaerobic and aerobic capacity and swimming performance in well-trained swimmers. Sixteen male swimmers were randomly divided into a hypoxia (H) group (n = 8), which trained in a normobaric hypoxia environment, and a control (C) group (n = 8), which exercised under normoxic conditions. However, one participant left the study without explanation. During the experiment group H trained on land twice per week in simulated hypoxia (FiO2 = 15.5%, corresponding to 2,500 m a.s.l); however, they conducted swim training in normoxic conditions. Group C performed the same training program under normoxic conditions. The training program included four weekly microcyles, followed by three days of recovery. During practice sessions on land, the swimmers performed 30 second sprints on an arm-ergometer, alternating with two minute high intensity intervals on a lower limb cycle ergometer. The results showed that the training on land caused a significant (pswimming performance, by 2.1% and 1.8%, respectively in group H. Training in normoxia (group C), resulted in a significant (pswimming performance at 100m and 200m, by 1.1% and 0.8%, respectively. In conclusion, the most important finding of this study includes a significant improvement in anaerobic capacity and swimming performance after high-intensity IHT. However, this training protocol had no effect on absolute values of VO2max and hematological variables. PMID:28763443

  8. 垃圾中含碳有机物厌氧降解过程的独立性探讨%Independence of Anaerobic Biodegradation of Carbonaceous Organic Materials

    Institute of Scientific and Technical Information of China (English)

    孙晓杰; 王敦球; 王洪涛; 陆文静; 张玲; 陆美菊; 吴安杰; 项振宇; 黄亮

    2011-01-01

    Independence of anaerobic biodegradation of carbonaceous organic material is of importance. It can provide theoretical basis for the simulation and prediction of the gasification characteristics and stabilization process. According to the research of the predecessor, this paper analyses the independence of anaerobic biodegradation of carbonaceous organic material. There might be catabolite repression in pure culture for bacteria, but not absolutely. During the landfill of the refuse, mutant resistant to the repressor may occur because micro-bial ecosystem is complex. The further study will go on for determining the independence of anaerobic biodegradation of carbonaceous organic material.%混合垃圾中单物质纤维素、淀粉、脂肪和蛋白质降解的独立性与否可为模拟和预测填埋场任意时刻的产气特性和稳定化进程提供依据.本文对单物质降解的独立性进行了探讨,已有的试验研究结果表明,在厌氧填埋环境下,单物质的厌氧产气量具有可叠加性,即各种单物质的降解是独立的.但是根据葡萄糖效应,在单一菌种纯培养试验中,会出现分解代谢物的阻遏作用,即难降解有机物的分解转化会受到易降解有机物的抑制.在垃圾填埋过程中,由于微生物生态系统复杂,可能会在具体环境中产生一些特殊的抗分解代谢物阻遏作用的微生物.如要从理论上确定填埋垃圾中有机物厌氧降解过程的独立性问题,需要设计专门的微生物学和酶学试验作进一步研究.

  9. The effect of tannic compounds on anaerobic wastewater treatment

    NARCIS (Netherlands)

    Field, J.A.

    1989-01-01

    Anaerobic wastewater treatment is an alternative to the conventional aerobic treatment processes for the removal of easily biodegradable organic matter in medium to high strength industrial wastestreams. Anaerobic treatment has several advantages, however one important disadvantage is the

  10. The effect of tannic compounds on anaerobic wastewater treatment.

    NARCIS (Netherlands)

    Field, J.A.

    1989-01-01

    Anaerobic wastewater treatment is an alternative to the conventional aerobic treatment processes for the removal of easily biodegradable organic matter in medium to high strength industrial wastestreams. Anaerobic treatment has several advantages, however one important disadvantage is the high sensi

  11. Removal of oxytetracycline (OTC) in a synthetic pharmaceutical wastewater by a sequential anaerobic multichamber bed reactor (AMCBR)/completely stirred tank reactor (CSTR) system: biodegradation and inhibition kinetics.

    Science.gov (United States)

    Sponza, Delia Teresa; Çelebi, Hakan

    2012-01-01

    An anaerobic multichamber bed reactor (AMCBR) was effective in removing both molasses-chemical oxygen demand (COD), and the antibiotic oxytetracycline (OTC). The maximum COD and OTC removals were 99% in sequential AMCBR/completely stirred tank reactor (CSTR) at an OTC concentration of 300 mg L(-1). 51%, 29% and 9% of the total volatile fatty acid (TVFA) was composed of acetic, propionic acid and butyric acids, respectively. The OTC loading rates at between 22.22 and 133.33 g OTC m(-3) d(-1) improved the hydrolysis of molasses-COD (k), the maximum specific utilization of molasses-COD (k(mh)) and the maximum specific utilization rate of TVFA (k(TVFA)). The direct effect of high OTC loadings (155.56 and -177.78 g OTC m(-3) d(-1)) on acidogens and methanogens were evaluated with Haldane inhibition kinetic. A significant decrease of the Haldane inhibition constant was indicative of increases in toxicity at increasing loading rates.

  12. Improvement of β-TCP/PLLA biodegradable material by surface modification with stearic acid.

    Science.gov (United States)

    Ma, Fengcang; Chen, Sai; Liu, Ping; Geng, Fang; Li, Wei; Liu, Xinkuan; He, Daihua; Pan, Deng

    2016-05-01

    Poly-L-lactide (PLLA) is a biodegradable polymer and used widely. Incorporation of beta tricalcium phosphate (β-TCP) into PLLA can enhance its osteoinductive properties. But the interfacial layer between β-TCP particles with PLLA matrix is easy to be destroyed due to inferior interfacial compatibility of the organic/inorganic material. In this work, a method of β-TCP surface modification with stearic acid was investigated to improve the β-TCP/PLLA biomaterial. The effects of surface modification on the β-TCP were investigated by FTIR, XPS, TGA and CA. It was found that the stearic acid reacted with β-TCP and oxhydryl was formed during the surface modification. Hydrophilicity of untreated or modified β-TCP/PLLA composite was increased by the addition of 10 wt.% β-TCP, but it decreased as the addition amount increased from 10 wt.% to 20 wt.%. Two models were suggested to describe the effect of β-TCP concentration on CA of the composites. Mechanical properties of β-TCP/PLLA composites were tested by bending and tensile tests. Fractures of the composites after mechanical test were observed by SEM. It was found that surface modification with stearic acid improved bending and tensile strengths of the β-TCP/PLLA composites obviously. The SEM results indicated that surface modification decreased the probability of interface debonding between fillers and matrix under load.

  13. 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)

  14. 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...

  15. Evaluating the ready biodegradability of two poorly water-soluble substances: comparative approach of bioavailability improvement methods (BIMs).

    Science.gov (United States)

    Sweetlove, Cyril; Chenèble, Jean-Charles; Barthel, Yves; Boualam, Marc; L'Haridon, Jacques; Thouand, Gérald

    2016-09-01

    Difficulties encountered in estimating the biodegradation of poorly water-soluble substances are often linked to their limited bioavailability to microorganisms. Many original bioavailability improvement methods (BIMs) have been described, but no global approach was proposed for a standardized comparison of these. The latter would be a valuable tool as part of a wider strategy for evaluating poorly water-soluble substances. The purpose of this study was to define an evaluation strategy following the assessment of different BIMs adapted to poorly water-soluble substances with ready biodegradability tests. The study was performed with two poorly water-soluble chemicals-a solid, anthraquinone, and a liquid, isodecyl neopentanoate-and five BIMs were compared to the direct addition method (reference method), i.e., (i) ultrasonic dispersion, (ii) adsorption onto silica gel, (iii) dispersion using an emulsifier, (iv) dispersion with silicone oil, and (v) dispersion with emulsifier and silicone oil. A two-phase evaluation strategy of solid and liquid chemicals was developed involving the selection of the most relevant BIMs for enhancing the biodegradability of tested substances. A description is given of a BIM classification ratio (R BIM), which enables a comparison to be made between the different test chemical sample preparation methods used in the various tests. Thereby, using this comparison, the BIMs giving rise to the greatest biodegradability were ultrasonic dispersion and dispersion with silicone oil or with silicone oil and emulsifier for the tested solid chemical, adsorption onto silica gel, and ultrasonic dispersion for the liquid one.

  16. Integrating spatial and temporal oxygen data to improve the quantification of in situ petroleum biodegradation rates.

    Science.gov (United States)

    Davis, Gregory B; Laslett, Dean; Patterson, Bradley M; Johnston, Colin D

    2013-03-15

    Accurate estimation of biodegradation rates during remediation of petroleum impacted soil and groundwater is critical to avoid excessive costs and to ensure remedial effectiveness. Oxygen depth profiles or oxygen consumption over time are often used separately to estimate the magnitude and timeframe for biodegradation of petroleum hydrocarbons in soil and subsurface environments. Each method has limitations. Here we integrate spatial and temporal oxygen concentration data from a field experiment to develop better estimates and more reliably quantify biodegradation rates. During a nine-month bioremediation trial, 84 sets of respiration rate data (where aeration was halted and oxygen consumption was measured over time) were collected from in situ oxygen sensors at multiple locations and depths across a diesel non-aqueous phase liquid (NAPL) contaminated subsurface. Additionally, detailed vertical soil moisture (air-filled porosity) and NAPL content profiles were determined. The spatial and temporal oxygen concentration (respiration) data were modeled assuming one-dimensional diffusion of oxygen through the soil profile which was open to the atmosphere. Point and vertically averaged biodegradation rates were determined, and compared to modeled data from a previous field trial. Point estimates of biodegradation rates assuming no diffusion ranged up to 58 mg kg(-1) day(-1) while rates accounting for diffusion ranged up to 87 mg kg(-1) day(-1). Typically, accounting for diffusion increased point biodegradation rate estimates by 15-75% and vertically averaged rates by 60-80% depending on the averaging method adopted. Importantly, ignoring diffusion led to overestimation of biodegradation rates where the location of measurement was outside the zone of NAPL contamination. Over or underestimation of biodegradation rate estimates leads to cost implications for successful remediation of petroleum impacted sites.

  17. Thermophilic and cellulolytic consortium isolated from composting plants improves anaerobic digestion of cellulosic biomass: Toward a microbial resource management approach.

    Science.gov (United States)

    Kinet, R; Destain, J; Hiligsmann, S; Thonart, P; Delhalle, L; Taminiau, B; Daube, G; Delvigne, F

    2015-01-01

    A cellulolytic consortium was isolated from a composting plant in order to boost the initial hydrolysis step encountered in anaerobic digestion. Improvement of the cellulose degradation, as well as biogas production, was observed for the cultures inoculated with the exogenous consortium. Metagenomics analyses pointed out a weak richness (related to the number of OTUs) of the exogenous consortium induced by the selective pressure (cellulose as sole carbon source) met during the initial isolation steps. Main microbial strains determined were strictly anaerobic and belong to the Clostridia class. During cellulose anaerobic degradation, pH drop induced a strong modification of the microbial population. Despite the fact that richness and evenness were very weak, the exogenous consortium was able to adapt and to maintain the cellulolytic degradation potential. This important result point out the fact that simplified microbial communities could be used in order to increase the robustness of mixed cultures involved in environmental biotechnology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. F-对厌氧颗粒污泥的产甲烷毒性及降解性能的影响%Effects of fluoride-containing effluents on methane production and biodegradation of anaerobic granular sludge

    Institute of Scientific and Technical Information of China (English)

    徐丽丽; 赵芝清; 沈晓莉; 方苗苗; 竺立; 傅柳松

    2012-01-01

    采用厌氧毒性试验(anaerobic toxicity assay,ATA)研究F-对厌氧颗粒污泥的产甲烷毒性.结果表明:当F-质量浓度为25 mg/L时,产甲烷过程几乎不受影响;当F-质量浓度由25 mg/L上升至100 mg/L时,产甲烷量由96 mL降至64mL;当F-质量浓度由100 mg/L上升至400 mg/L时,产甲烷量仅由64 mL降至60 mL.随之2次连续投加F-的试验结果表明:当F-质量浓度为25 mg/L时,甲烷化过程仍然保持与对照相当的活性;当F-质量浓度为100~400 mg/L时,甲烷化过程则受到了更为严重的抑制.恢复试验结果表明:当F-质量浓度为25和100~400 mg/L时,F-分别属于代谢毒素和生理毒素.此外,蔗糖基质的降解性随着F-质量浓度的增加而降低.%Fluoride is major raw material of chemical industry and is also the main pernicious composition in industrial wastewater, which leads to serious environmental pollution. Anaerobic biological treatment technology is a kind of low cost wastewater treatment technology which combines wastewater treatment with energy recovery. The prospects for the anaerobic wastewater treatment are extremely promising. However, the bioactivity of anaerobic microorganism, especially the methanogens can be hampered seriously by toxic and harmful substances, such as nitrophenol positional isomers, PCP (pentachlorophenol), polycyclic aromatic hydrocarbon, fluoride-containing effluents, etc. Furthermore, the vailable information about the effects of fluoride-containing effluents on the methane production and biodegradation process of anaerobic microbe in biological wastewater treatment is very limited at present. The purpose of this study is to evaluate the inhibitory effect of fluoride against the main microbial populations expressing in the methanogenic activity and the recovery of the biological activity. To attain this goal, a short-term batch anaerobic toxicity test (ATA) was conducted. The batch test was consisted of five parts, namely, the first, the

  19. Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment.

    Science.gov (United States)

    Smith, Adam L; Skerlos, Steven J; Raskin, Lutgarde

    2015-09-01

    Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.

  20. Cloning and expression of vgb gene in Bacillus cereus, improve phenol and p-nitrophenol biodegradation

    Science.gov (United States)

    Vélez-Lee, Angel Eduardo; Cordova-Lozano, Felipe; Bandala, Erick R.; Sanchez-Salas, Jose Luis

    2016-02-01

    In this work, the vgb gene from Vitrocilla stercoraria was used to genetically modify a Bacillus cereus strain isolated from pulp and paper wastewater effluent. The gene was cloned in a multicopy plasmid (pUB110) or uni-copy gene using a chromosome integrative vector (pTrpBG1). B. cereus and its recombinant strains were used for phenol and p-nitrophenol biodegradation using aerobic or micro-aerobic conditions and two different temperatures (i.e. 37 and 25 °C). Complete (100%) phenol degradation was obtained for the strain where the multicopy of vgb gene was present, 98% for the strain where uni-copy gene was present and 45% for wild type strain for the same experimental conditions (i.e. 37 °C and aerobic condition). For p-nitrophenol degradation at the same conditions, the strain with the multi-copy vgb gene was capable to achieve 50% of biodegradation, ˜100% biodegradation was obtained using the uni-copy strain and ˜24% for wild type strain. When the micro-aerobic condition was tested, the biodegradation yield showed a significant decreased. The biodegradation trend observed for aerobic was similar for micro-aerobic assessments: the modified strains showed higher degradation rates when compared with wild type strain. For all experimental conditions, the highest p-nitrophenol degradation was observed using the strain with uni-copy of vgb gene. Besides the increase of biodegradative capability of the strain, insertion of the vgb gene was observed able to modify other morphological characteristics such as avoiding the typical flake formation in the B. cereus culture. In both cases, the modification seems to be related with the enhancement of oxygen supply to the cells generated by the vgb gene insertion. The application of the genetically modified microorganism (GMM) to the biodegradation of pollutants in contaminated water possesses high potential as an environmentally friendly technology to facing this emergent problem.

  1. Improvement of water barrier property of paperboard by coating application with biodegradable polymers.

    Science.gov (United States)

    Han, Jaejoon; Salmieri, Stéphane; Le Tien, Canh; Lacroix, Monique

    2010-03-10

    Biopolymeric coatings were prepared and applied onto paperboard to improve its water barrier property. To prepare whey protein isolate (WPI)/cellulose-based films, WPI and glycerol were dissolved in water with glutaraldehyde (cross-linking agent) and cellulose xanthate. The solution was cast, dried, and insolubilized by entrapment of WPI in regenerated cellulose. Films were combined with beeswax (BW) into a bilayer coating system and then applied onto paperboard by heating compression. Another coating solution consisting of poly(vinyl butyral) (PVB)/zein was prepared by dissolving poly(vinyl alcohol) (PVA) and zein in 70% ethanol with glutaraldehyde and butyraldehyde (functionalization agent). The PVB/zein solution was applied onto paperboard after BW was sprayed. The structure of the PVB/zein-based coatings was analyzed by Fourier transform infrared spectroscopy (FTIR). The water vapor barrier property of coated paperboards was evaluated by water vapor transmission rate (WVTR) measurements. From the FTIR spectra, PVA functionalization after cross-linking and efficient acetalization into PVB were confirmed. WPI/cellulose and PVB/zein coating treatments improved the water barrier properties of paperboard by decreasing the WVTR by 77-78%. Although the BW coating was more efficient (decrease of WVTR by 89%), bilayer coatings composed of BW and polymer coatings had a stronger barrier effect with a decrease of WVTR to 92-95%, hence approaching commercial attributes required to ensure water vapor barrier in paperboard-based food containers (10 g/m(2).day). These results suggest that surface coating by biodegradable polymers may be utilized for the manufacture of paperboard containers in industrial applications.

  2. Creatine supplementation improves the anaerobic performance of elite junior fin swimmers.

    Science.gov (United States)

    Juhász, Imre; Györe, I; Csende, Zs; Rácz, L; Tihanyi, J

    2009-09-01

    The objective of this study was to determine whether creatine supplementation (CrS) could improve mechanical power output, and swimming performance in highly trained junior competitive fin swimmers. Sixteen male fin swimmers (age:15.9+/-1.6 years) were randomly and evenly assigned to either a creatine (CR, 4x5 g/day creatine monohydrate for 5 days) or placebo group (P, same dose of a dextrose-ascorbic acid placebo) in a double-blind research. Before and after CrS the average power output was determined by a Bosco-test and the swimming time was measured in two maximal 100 m fin swims. After five days of CrS the average power of one minute continuous rebound jumps increased by 20.2%. The lactate concentration was significantly less after 5 minutes restitution at the second measurement in both groups. The swimming time was significantly reduced in both first (pre: 50.69+/-1.41 s; post: 48.86+/-1.34 s) and second (pre: 50.39+/-1.38 s; post: 48.53+/-1.35 s) sessions of swimming in CR group, but remained almost unchanged in the P group.The results of this study indicate that five day Cr supplementation enhances the dynamic strength and may increase anaerobic metabolism in the lower extremity muscles, and improves performance in consecutive maximal swims in highly trained adolescent fin swimmers.

  3. 含盐条件下偶氮染料兼厌氧性生物的降解性能%Facultative anaerobic biodegradation performance of azo dyestuff under salt-containing condition

    Institute of Scientific and Technical Information of China (English)

    雷弢; 仝攀瑞; 陈方方; 王晓艳

    2011-01-01

    The facultstive anaerobic biodegradation performance of reactive dyestuffs is studied by using different concentrations glucose. And based on this conclusion, the facultative anaerobic biodegradation performance of K-2BP under different salt-containlng condition is investigated by static test reactor. The results indicate that facultative anaerobic microorganisms has lower degradation rate when only K-2BP is used as the substrate, and the degradation rate would be increased under the existence of the glucose. The glucose concentration is 800 mg/L, while the degradation rate of K-2BP is 64. 1% in 6h. However, it is detrimental to dye's biodegradation when the glucose concentration is up to 1 000 mg/L, the degradation rate is only about 46%, that is similar to the condition of non-glucose. On the premise of glucose concentration 800 mg/L, when the salt concentrations are 2 g/L,5 g/L,l0 g/L and 20 g/L respectively,the first-order kinetics constants are 0. 10578 mg/L· h,0. 04947mg/L · h,0.028 69mg/L · h and 0.022 75mg/L · h respectively. And the half-lives are 6.99h,14. 15h,22.55h and 30.21h respectively. The reaction rate constants is daereased gradually with the salt concentrations'incresse,which is showed that high salt concentration can restrainthe facultative anaerobic microorganisms' degradation of K-2BP.%研究活性染料与不同浓度葡萄糖共基质条件下的兼厌氧性生物降解性能和K-2BP在不同盐浓度条件下的兼厌氧性生物降解性能.选择K-2BP作为目标污染物进行静态反应器生物降解实验.结果表明,兼厌氧性微生物在只有K-2BP作为基质时对染料的降解率较低,葡萄糖存在时,能提高兼厌氧性生物对染料的降解能力;葡萄糖为800mg/L时6h染料降解率为64.1%,而葡萄糖浓度为1 000mg/L时,不利于染料降解,6h染料降解率为46%,与不投加葡萄糖情况的降解率接近.葡萄糖浓度为800mg/L,盐浓度分别为2g/L,5g/L,10g/L和20g/L,其一级

  4. Use of Fenton oxidation to improve the biodegradability of a pharmaceutical wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Tekin, Huseyin [ENCON Environmental Consultancy Co., Mahatma Gandhi Caddesi 75/3, Gaziosmanpasa, 06700 Ankara (Turkey); Bilkay, Okan [ENCON Environmental Consultancy Co., Mahatma Gandhi Caddesi 75/3, Gaziosmanpasa, 06700 Ankara (Turkey); Ataberk, Selale S. [ENCON Environmental Consultancy Co., Mahatma Gandhi Caddesi 75/3, Gaziosmanpasa, 06700 Ankara (Turkey); Balta, Tolga H. [ENCON Environmental Consultancy Co., Mahatma Gandhi Caddesi 75/3, Gaziosmanpasa, 06700 Ankara (Turkey); Ceribasi, I. Haluk [ENCON Environmental Consultancy Co., Mahatma Gandhi Caddesi 75/3, Gaziosmanpasa, 06700 Ankara (Turkey); Sanin, F. Dilek [Department of Environmental Engineering, Middle East Technical University, 06531 Ankara (Turkey); Dilek, Filiz B. [Department of Environmental Engineering, Middle East Technical University, 06531 Ankara (Turkey); Yetis, Ulku [Department of Environmental Engineering, Middle East Technical University, 06531 Ankara (Turkey)]. E-mail: uyetis@metu.edu.tr

    2006-08-21

    The applicability of Fenton's oxidation to improve the biodegradability of a pharmaceutical wastewater to be treated biologically was investigated. The wastewater was originated from a factory producing a variety of pharmaceutical chemicals. Treatability studies were conducted under laboratory conditions with all chemicals (having COD varying from 900 to 7000 mg/L) produced in the factory in order to determine the operational conditions to utilize in the full-scale treatment plant. Optimum pH was determined as 3.5 and 7.0 for the first (oxidation) and second stage (coagulation) of the Fenton process, respectively. For all chemicals, COD removal efficiency was highest when the molar ratio of H{sub 2}O{sub 2}/Fe{sup 2+} was 150-250. At H{sub 2}O{sub 2}/Fe{sup 2+} ratio of 155, 0.3 M H{sub 2}O{sub 2} and 0.002 M Fe{sup 2+}, provided 45-65% COD removal. The wastewater treatment plant that employs Fenton oxidation followed by aerobic degradation in sequencing batch reactors (SBR), built after these treatability studies provided an overall COD removal efficiency of 98%, and compliance with the discharge limits. The efficiency of the Fenton's oxidation was around 45-50% and the efficiency in the SBR system which has two reactors each having a volume of 8 m{sup 3} and operated with a total cycle time of 1 day, was around 98%, regarding the COD removal.

  5. Exocellular electron transfer in anaerobic microbial communities

    NARCIS (Netherlands)

    Stams, A.J.M.; Bok, de F.A.M.; Plugge, C.M.; Eekert, van M.H.A.; Dolfing, J.; Schraa, G.

    2006-01-01

    Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory

  6. Exocellular electron transfer in anaerobic microbial communities

    NARCIS (Netherlands)

    Stams, A.J.M.; Bok, de F.A.M.; Plugge, C.M.; Eekert, van M.H.A.; Dolfing, J.; Schraa, G.

    2006-01-01

    Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory

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

    Directory of Open Access Journals (Sweden)

    WRT Lopes

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

  8. Efficacy of a Ventilatory Training Mask to Improve Anaerobic and Aerobic Capacity in Reserve Officers' Training Corps Cadets.

    Science.gov (United States)

    Sellers, John H; Monaghan, Taylor P; Schnaiter, Jessica A; Jacobson, Bert H; Pope, Zachary K

    2016-04-01

    The purpose of this study was to examine the efficacy of a ventilatory training mask to improve anaerobic and aerobic fitness in reserve officers' training corps (ROTC) cadets. Seventeen ROTC cadets from a Midwest university completed pre- and postassessments consisting of anthropometry, a 30-second Wingate Anaerobic Test (WAnT), and a maximal aerobic capacity test (V[Combining Dot Above]O2max). A 6-week intervention training period was used during which time participants completed their mandatory physical training (PT) sessions. Participants were randomly assigned to either the experimental group (MASK; n = 9) or the control group (CON; n = 8). The ventilatory training masks were adjusted to simulate an altitude of 2,750 m. There was no significant effect (p ≤ 0.05) between groups on fatigue index, anaerobic capacity, peak power, V[Combining Dot Above]O2max, or time to exhaustion. These results suggest that the use of the ventilatory training mask during mandatory PT did not elicit superior aerobic or anaerobic adaptations in ROTC cadets. Therefore, it is recommended that more established simulated altitude training methods be used when incorporating intermittent hypoxic training.

  9. Anaerobic degradation and toxicity of commercial cationic surfactants in anaerobic screening tests.

    Science.gov (United States)

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

    2000-09-01

    Anaerobic biodegradability and toxicity on anaerobic bacteria of di(hydrogenated tallow) dimethyl ammonium chloride (DHTDMAC) and two esterquats have been investigated. A batch test system containing municipal digester solids as a source of anaerobic bacteria, based on the method proposed by the ECETOC, has been applied. To evaluate the potential toxicity of such surfactants on anaerobic sludge, a co-substrate, an easily biodegradable compound in anaerobic conditions, has been added to the samples to test and the effects on biogas production have been determined. For the esterquats studied high biodegradation levels were obtained and no toxic effects on anaerobic bacteria were observed even at the highest concentrations tested, 100 and 200 mg C/l, respectively. On the contrary, DHTDMAC was not degradated at the same test conditions. However, no inhibitory effects on the biogas production were detected for this surfactant at concentrations <100 mg C/l.

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

    Science.gov (United States)

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

    2012-05-01

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

  11. Biodegradation of Reactive blue 13 in a two-stage anaerobic/aerobic fluidized beds system with a Pseudomonas sp. isolate.

    Science.gov (United States)

    Lin, Jun; Zhang, Xingwang; Li, Zhongjian; Lei, Lecheng

    2010-01-01

    Pseudomonas sp. strain L1 capable of degrading the azo textile dye Reactive blue 13, was isolated from activated sludge in a sequencing batch reactor. A continuous two-stage anaerobic/aerobic biological fluidized bed system was used to decolorize and mineralize Reactive blue 13. The key factors affecting decolorization were investigated and the efficiency of degradation was also optimized. An overall color removal of 83.2% and COD removal of 90.7% was achieved at pH 7, a residence time of 70 h and a glucose concentration of 2 g/L, HRT=70 h and C(glucose)=2000 mg/L. Oxygen was contributing to blocking the azo bond cleavage. Consequently, decolorization occurred in the anaerobic reactor while partial mineralization was achieved in the aerobic reactor. A possible degradation pathway based on the analysis of intermediates and involving azoreduction, desulfonation, deamination and further oxidation reactions is presented.

  12. A biodegradation and treatment of palm oil mill effluent (POME) using a hybrid up-flow anaerobic sludge bed (HUASB) Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Habeeb, S.A.; Latiff, AB. Aziz Abdul; Daud, Zawawi; Ahmad, Zulkifli [Faculty of Civil and Enviromental Engineering, University Tun Hussein Onn (Malaysia)

    2011-07-01

    Generally, anaerobic treatment has become a viable alternative in support of industrial wastewater treatment. Particularly, it is used in common to treat the palm oil mill effluent (POME). This study was carried out to assess the start-up performance of a bioreactor hybrid up-flow anaerobic sludge blanket (HUASB). Whereby, three identical reactors of 7.85-l capacity R1, R2, and R3 were operated for 57 days in order to provide two alienated comparisons. Identical operation conditions of organic loading rate (OLR) and hydraulic retention time (HRT) of 1.85 kg.m-3.day-1, and 2.6 day, respectively. R1 was operated in room temperature of 28{+-}2 C, and packed with palm oil shell as filter medium support. R2 was set with room temperature but packed with course gravel. R3 was provided with water bath system to adjust its temperature at 37{+-}1 C mesophilic, while its filter material had to be palm oil shell. During the whole operation period R3 was more efficient for organic materials, where a chemical oxygen demand (COD) removal efficiency of 82% was registered, while R1 and R2 were relatively less efficient of 78%, and 76%, respectively. Furthermore, TSS removal of R3 was also higher than R1, and R2 as registered 80%, 77% and 76%, respectively. On the other hand, turbidity and colour removal were not efficient and needed a post treatment. The seeded sludge was developed in each reactor as illustrated in this paper. Therefore, all reactors show favorable performance of anaerobic treatability of POME as well as good response of microbial species development.

  13. A biodegradation and treatment of palm oil mill effluent (POME using a hybrid up-flow anaerobic sludge bed (HUASB reactor

    Directory of Open Access Journals (Sweden)

    S. A. Habeeb, AB. Aziz Abdul Latiff, Zawawi Daud, Zulkifli Ahmad

    2011-07-01

    Full Text Available Generally, anaerobic treatment has become a viable alternative in support of industrial wastewater treatment. Particularly, it is used in common to treat the palm oil mill effluent (POME. This study was carried out to assess the start-up performance of a bioreactor hybrid up-flow anaerobic sludge blanket (HUASB. Whereby, three identical reactors of 7.85-l capacity R1, R2, and R3 were operated for 57 days in order to provide two alienated comparisons. Identical operation conditions of organic loading rate (OLR and hydraulic retention time (HRT of 1.85 kg.m-3.day-1, and 2.6 day, respectively. R1 was operated in room temperature of 28±2°C, and packed with palm oil shell as filter medium support. R2 was set with room temperature but packed with course gravel. R3 was provided with water bath system to adjust its temperature at 37±1°C mesophilic, while its filter material had to be palm oil shell. During the whole operation period R3 was more efficient for organic materials, where a chemical oxygen demand (COD removal efficiency of 82% was registered, while R1 and R2 were relatively less efficient of 78%, and 76%, respectively. Furthermore, TSS removal of R3 was also higher than R1, and R2 as registered 80%, 77% and 76%, respectively. On the other hand, turbidity and colour removal were not efficient and needed a post treatment. The seeded sludge was developed in each reactor as illustrated in this paper. Therefore, all reactors show favorable performance of anaerobic treatability of POME as well as good response of microbial species development.

  14. Conventional and improved cytotoxicity test methods of newly developed biodegradable magnesium alloys

    Science.gov (United States)

    Han, Hyung-Seop; Kim, Hee-Kyoung; Kim, Yu-Chan; Seok, Hyun-Kwang; Kim, Young-Yul

    2015-11-01

    Unique biodegradable property of magnesium has spawned countless studies to develop ideal biodegradable orthopedic implant materials in the last decade. However, due to the rapid pH change and extensive amount of hydrogen gas generated during biocorrosion, it is extremely difficult to determine the accurate cytotoxicity of newly developed magnesium alloys using the existing methods. Herein, we report a new method to accurately determine the cytotoxicity of magnesium alloys with varying corrosion rate while taking in-vivo condition into the consideration. For conventional method, extract quantities of each metal ion were determined using ICP-MS and the result showed that the cytotoxicity due to pH change caused by corrosion affected the cell viability rather than the intrinsic cytotoxicity of magnesium alloy. In physiological environment, pH is regulated and adjusted within normal pH (˜7.4) range by homeostasis. Two new methods using pH buffered extracts were proposed and performed to show that environmental buffering effect of pH, dilution of the extract, and the regulation of eluate surface area must be taken into consideration for accurate cytotoxicity measurement of biodegradable magnesium alloys.

  15. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  16. Improving biogas production from anaerobic co-digestion of sewage sludge with a thermal dried mixture of food waste, cheese whey and olive mill wastewater.

    Science.gov (United States)

    Maragkaki, A E; Vasileiadis, I; Fountoulakis, M; Kyriakou, A; Lasaridi, K; Manios, T

    2017-08-11

    Anaerobic co-digestion of sewage sludge and other organic wastes at a wastewater treatment plant (WWTP) is a promising method for both energy and material recovery. However, transportation and storage of wastes to WWTP may be the bottleneck for the successful implementation of this technology. In case of wet wastes and wastewater it is possible to reduce their volume and as a result the transportation and storage cost by using a drying process. During this study, the optimization of biogas production from sewage sludge (SS) was attempted by co-digesting with a dried mixture of food waste, cheese whey and olive mill wastewater (FCO). A series of laboratory experiments were performed in continuously-operating reactors at 37°C, fed with thermal dried mixtures of FCO at concentrations of 3%, 5% and 7%. The overall process was designed with a hydraulic retention time (HRT) of 24days. FCO addition can boost biogas yields if the mixture exceeds 3% (v/v) concentration in the feed. Any further increase of 5% FCO causes a small increase in biogas production. The reactor treating the sewage sludge produced 287ml CH4/Lreactor/d before the addition of FCO and 815ml CH4/Lreactor/d (5% v/v in the feed). The extra FCO-COD added (7% FCO v/v) to the feed did not have a negative effect on reactor performance, but seemed to have the same results. In all cases, the estimated biodegradability of mixtures was over 80%, while the VS removal was 22% for the maximum biomethane production (5% v/v). Moreover, co-digestion improved biogas production by 1.2-2.7 times. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Serial completely stirred tank reactors for improving biogas production and substance degradation during anaerobic digestion of corn stover.

    Science.gov (United States)

    Li, YuQian; Liu, ChunMei; Wachemo, Akiber Chufo; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Li, XiuJin

    2017-07-01

    Several completely stirred tank reactors (CSTR) connected in series for anaerobic digestion of corn stover were investigated in laboratory scale. Serial anaerobic digestion systems operated at a total HRT of 40days, and distribution of HRT are 10+30days (HRT10+30d), 20+20days (HRT20+20d), and 30+10days (HRT30+10d) were compared to a conventional one-step CSTR at the same HRT of 40d. The results showed that in HRT10+30d serial system, the process became very unstable at organic load of 50gTS·L(-1). The HRT20+20d and HRT30+10d serial systems improved methane production by 8.3-14.6% compared to the one-step system in all loads of 50, 70, 90gTS·L(-1). The conversion rates of total solid, cellulose, and hemicellulose were increased in serial anaerobic digestion systems compared to single system. The serial systems showed more stable process performance in high organic load. HRT30+10d system showed the best biogas production and conversions among all systems. Copyright © 2017. Published by Elsevier Ltd.

  19. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically...... increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  20. Improving rice production sustainability by reducing water demand and greenhouse gas emissions with biodegradable films

    Science.gov (United States)

    Yao, Zhisheng; Zheng, Xunhua; Liu, Chunyan; Lin, Shan; Zuo, Qiang; Butterbach-Bahl, Klaus

    2017-01-01

    In China, rice production is facing unprecedented challenges, including the increasing demand, looming water crisis and on-going climate change. Thus, producing more rice at lower environmental cost is required for future development, i.e., the use of less water and the production of fewer greenhouse gas (GHG) per unit of rice. Ground cover rice production systems (GCRPSs) could potentially address these concerns, although no studies have systematically and simultaneously evaluated the benefits of GCRPS regarding yields and considering water use and GHG emissions. This study reports the results of a 2-year study comparing conventional paddy and various GCRPS practices. Relative to conventional paddy, GCRPSs had greater rice yields and nitrogen use efficiencies (8.5% and 70%, respectively), required less irrigation (-64%) and resulted in less total CH4 and N2O emissions (-54%). On average, annual emission factors of N2O were 1.67% and 2.00% for conventional paddy and GCRPS, respectively. A cost-benefit analysis considering yields, GHG emissions, water demand and labor and mulching costs indicated GCRPSs are an environmentally and economically profitable technology. Furthermore, substituting the polyethylene film with a biodegradable film resulted in comparable benefits of yield and climate. Overall, GCRPSs, particularly with biodegradable films, provide a promising solution for farmers to secure or even increase yields while reducing the environmental footprint.

  1. Simultaneous mechanical property and biodegradation improvement of wollastonite bioceramic through magnesium dilute doping.

    Science.gov (United States)

    Xie, Jiajun; Yang, Xianyan; Shao, Huifeng; Ye, Juan; He, Yong; Fu, Jianzhong; Gao, Changyou; Gou, Zhongru

    2016-02-01

    The large-area bone defects in head (including calvarial, orbital, and maxillofacial bone) and segmental bone are attracting increased attention in a wide range of clinical departments. A key requirement for the clinical success of the bioactive ceramics is the match of the mechanical behavior of the implants with the specific bone tissue to be filled. This raises the question as to what design strategy might be the best indicators for the balance between mechanical properties and biological performances. Here we go beyond the traditional approaches that use phase conversion or biphasic hybrid; instead, we achieved a simultaneous enhancement of several mechanical parameters and optimalization of biodegradability by using a dilute doping of Mg in a single-phase wollastonite bioceramic. We show that the wollastonite ceramic can be rationally tuned in phase (α or β), mechanical strength (in compression and bending mode), elastic modulus (18-23GPa), and fracture toughness (>3.2MPam(1/2)) through the usage of Mg dopant introduced at precisely defined dilute concentrations (Mg/Ca molar ratio: 1.2-2.1%). Meanwhile, the dilute Mg-doped wollastonite ceramics are shown to exhibit good bioactivity in vitro in SBF but biodegradation in Tris is inversely proportional to Mg content. Consequently, such new highly bioactive ceramics with appreciable strength and toughness are promising for making specific porous scaffolds for enhancing large segmental bone defect and thin-wall bone defect repair.

  2. Anaerobic modeling for improving synergy and robustness of a manure co-digestion process

    DEFF Research Database (Denmark)

    Lima, D. M. F.; Rodrigues, J. A. D.; Boe, Kanokwan

    2016-01-01

    Biogas production is becoming increasingly important in the environmental area because, besides treating wastewaters, it also generates energy. Co-digestion has become more and more powerful since it is possible, with the use of abundant and cheap substrates, to dilute the inhibitory effects...... of various other substrates, making the process of anaerobic digestion more efficient and stable. Biogas process modelling describes the kinetics and stoichiometry of different steps in the anaerobic digestion process. This mathematical modelling provides an understanding of the processes and interactions...... occurring inside the biogas system. The present work investigated the interactions between different simple co-substrates (carbohydrate, lipid and protein) and real co-substrates (corn silage, fodder beet, grass and wheat straw) under co-digestion with manure, in order to verify synergetic effects...

  3. ANAEROBIC MODELING FOR IMPROVING SYNERGY AND ROBUSTNESS OF A MANURE CO-DIGESTION PROCESS

    Directory of Open Access Journals (Sweden)

    D. M. F. Lima

    Full Text Available Abstract Biogas production is becoming increasingly important in the environmental area because, besides treating wastewaters, it also generates energy. Co-digestion has become more and more powerful since it is possible, with the use of abundant and cheap substrates, to dilute the inhibitory effects of various other substrates, making the process of anaerobic digestion more efficient and stable. Biogas process modelling describes the kinetics and stoichiometry of different steps in the anaerobic digestion process. This mathematical modelling provides an understanding of the processes and interactions occurring inside the biogas system. The present work investigated the interactions between different simple co-substrates (carbohydrate, lipid and protein and real co-substrates (corn silage, fodder beet, grass and wheat straw under co-digestion with manure, in order to verify synergetic effects. Subsequently, some experiments were reproduced, in order to evaluate the synergy obtained in the previous simulation and validate the model.

  4. 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...

  5. 厌氧微生物降解多环芳烃研究进展%Progresses in anaerobic biodegradation of polycyclic aromatic hydrocarbons——A review

    Institute of Scientific and Technical Information of China (English)

    孙明明; 滕应; 骆永明

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a recalcitrant group of contaminants in the environment.PAHs degradation has been extensively studied and well understood under aerobic conditions, whereas little is known about anaerobic degradation of PAHs.Here, we reviewed recent progress in anaerobic degradation of PAHs.We focused on naphthalene and phenanthrene as model compounds.We addressed the main rate-limiting factors involved, including the bioaccessibility of PAHs, the amendment of nutrients and elector acceptors, the degrading microorganisms, and the biochemistry of the initial activation and subsequent enzyme reaction involved in the pathway.Prospects on this field are also discussed.%多环芳烃(PAHs)是一类普遍存在于环境介质中的难降解有机污染物,相对于好氧微生物降解PAHs的研究,厌氧微生物降解PAHs的研究则相对较少.本文从厌氧微生物降解PAHs的研究背景,厌氧降解微生物的特点和不同厌氧降解还原反应体系的角度综述了厌氧微生物降解PAHs的概况;结合厌氧微生物降解萘和菲转化途径的介绍,推断了其降解机制的内在原因;同时通过总结影响厌氧微生物降解PAHs的主要因素(包括:PAHs的生物可利用性、外源营养物质的添加、外源电子受体的添加、特定厌氧降解菌的筛选强化和部分环境因素等),指出了制约降解进程的潜在限制因子;并对厌氧微生物降解PAHs研究目前存在的问题和未来的发展方向作了简述与展望.

  6. Sequential anaerobic-aerobic biodegradation of 2,3,7,8-TCDD contaminated soil in the presence of CMC-coated nZVI and surfactant.

    Science.gov (United States)

    Binh, Nguyen Duy; Imsapsangworn, Chaiyaporn; Kim Oanh, Nguyen Thi; Parkpian, Preeda; Karstensen, Kare; Giao, Pham Huy; DeLaune, Ronald D

    2016-01-01

    Enriched microorganisms in sediment collected from a dioxin-contaminated site in Vietnam (Bien Hoa airbase) were used for examining the effectiveness in biological treatment of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in soil. Four bio-treatments were investigated using a sequential anaerobic (17 weeks) followed by an aerobic (6 weeks) incubation. The maximum removal efficiency was approximately 60% even at an extremely low pH (approx. 3.6) condition. Surfactant Tween-80 was added to enhance the bioavailability of dioxin in two treatments, but it appeared to biostimulate methanogens rather than dechlorinators. As a result, methane production was the highest while the dioxin removal efficiency was the lowest, as compared with the other bio-treatments. Carboxymethylcellulose (CMC) coated on nanoscale zero valent iron (nZVI) surface used in two treatments could prevent the direct contact between bacterial cell surface and nZVI which prevented cell death and lysis, hence enhancing dioxin removal. The presence of CMC--_nZVI in bio-treatments gradually released H2 required for microbiological processes, but the amount used in the experiments were likely too high to maintain optimum H2 levels for biostimulating dechlorinators rather than methanogens.

  7. Study of microbial community and biodegradation efficiency for single- and two-phase anaerobic co-digestion of brown water and food waste.

    Science.gov (United States)

    Lim, J W; Chen, C-L; Ho, I J R; Wang, J-Y

    2013-11-01

    The objective of this work was to study the microbial community and reactor performance for the anaerobic co-digestion of brown water and food waste in single- and two-phase continuously stirred tank reactors (CSTRs). Bacterial and archaeal communities were analyzed after 150 days of reactor operation. As compared to single-phase CSTR, methane production in two-phase CSTR was found to be 23% higher. This was likely due to greater extent of solubilization and acidification observed in the latter. These findings could be attributed to the predominance of Firmicutes and greater bacterial diversity in two-phase CSTR, and the lack of Firmicutes in single-phase CSTR. Methanosaeta was predominant in both CSTRs and this correlated to low levels of acetate in their effluent. Insights gained from this study would enhance the understanding of microorganisms involved in co-digestion of brown water and food waste as well as the complex biochemical interactions promoting digester stability and performance.

  8. Experimental Research on Biodegradability of 2-hydroxy-3-naphthalene Hydroxamic Acid H205 Under Anaerobic Conditions%2-羟基-3-萘甲羟肟酸(H205)的厌氧生物降解性试验研究

    Institute of Scientific and Technical Information of China (English)

    韩惟怡; 龚文琪; 梅光军

    2012-01-01

    采用摇瓶振荡培养法,研究了2-羟基-3-萘甲羟肟酸(H205)在4种厌氧条件下的生物降解性.结果表明:在整个试验周期内,各种非生物因素对H205的厌氧生物降解过程的影响可忽略不计.H205在反硝化、硫酸盐还原与Fe(Ⅲ)还原体系中的生物降解效率优于一般厌氧处理.H205在不同的厌氧条件下的降解速率由低到高依次为一般厌氧处理、硫酸盐还原处理、反硝化处理以及Fe(Ⅲ)还原处理.Fe(Ⅲ)是H205厌氧生物降解的最适宜电子受体.H205在不同厌氧条件下的生物降解都符合一级动力学模型,一般厌氧条件、反硝化条件、硫酸盐条件和Fe(Ⅲ)条件下的动力学方程分别为C=29.86e0.014 77t,C=29.91e0.042 761,C=29.89e0.026 23t,C=29.95e0.055 97t.最后初步探讨了H205的厌氧生物降解机理.%The biodegradability of 2-hydroxy-3-naphthalene hydroxamic acid (H2O5) was investigated by shaking-bottle incubating tests under four anaerobic conditions. The result indicated that; in the whole test period, the influence of various non-biological factors on the biodegradation of H205 under the anaerobic conditions can be ignored. Under three reductive conditions such as denitrification, sulfate reduction and Fe( Ⅲ) reduction the biodegradation rates of H2O5 were higher than that under general anaerobic condition. The increasing order of the biodegradation rate of H2O5 was as follows: general anaerobic treatment, sulfate-reducing treatment, nitrate-reducing treatment and Fe( Ⅲ )-reducing treatment. Ferric I-ron was a more favorable terminal electron acceptor compared to nitrate and sulfate for biodegradability of H205. The biodegradation of H205 followed the first order reaction kinetics equation under general anaerobic, nitrate-reducing, sulfate-reducing and Fe( HI )-reducing conditions. The respective biodegradation reaction kinetics equations are C=29. 86e0.01477t, C=29. 91e0.042 75t, C=29. 89e0.026 231t, C=29. 95e0.055 97 t

  9. Enhancement of Taihu blue algae anaerobic digestion efficiency by natural storage.

    Science.gov (United States)

    Miao, Hengfeng; Lu, Minfeng; Zhao, Mingxing; Huang, Zhenxing; Ren, Hongyan; Yan, Qun; Ruan, Wenquan

    2013-12-01

    Taihu blue algae after different storage time from 0 to 60 d were anaerobic fermented to evaluate their digestibility and process stability. Results showed that anaerobic digestion (AD) of blue algae under 15 d natural storage led to the highest CH4 production of 287.6 mL g(-1) VS at inoculum substrate ratio 2.0, demonstrating 36.69% improvement comparing with that from fresh algae. Storage of blue algae led to cell death, microcystins (MCs) release and VS reduction by spontaneous fermentation. However, it also played an important role in removing algal cell wall barrier, pre-hydrolysis and pre-acidification, leading to the improvement in CH4 yield. Closer examination of volatile fatty acids (VFA) variation, VS removal rates and key enzymes change during AD proved short storage time (≤ 15 d) of blue algae had higher efficiencies in biodegradation and methanation. Furthermore, AD presented significant biodegradation potential for MCs released from Taihu blue algae.

  10. Novel magnesium-nanofluorapatite metal matrix nanocomposite with improved biodegradation behavior.

    Science.gov (United States)

    Fathi, M H; Meratian, M; Razavi, M

    2011-06-01

    Designing and preparation of magnesium alloys with adjustable biocorrosion rates in the human body and precipitation ability of bone-like apatite layer have been of interest recently. Application of metal matrix composites (MMC) based on magnesium alloys might be an approach to this challenge. The aim of this work was fabrication and evaluation of biocorrosion and bioactivity of a novel MMC made of magnesium alloy AZ91 as matrix and fluorapatite (FA) nano particles as reinforcement. Biodegradable Magnesium-nano fluorapatite metal matrix nanocomposite (AZ91-20FA) was made via a blending-pressing-sintering method. In vitro corrosion tests were performed for evaluation of biocorrosion behavior of produced AZ91-20FA nanocomposite. The results showed that the addition of FA nano particles to magnesium alloy can reduce not only the corrosion rate in a simulated body environment but also accelerate the formation of an apatite layer.

  11. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Hakimi, O.; Aghion, E. [Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Goldman, J., E-mail: jgoldman@mtu.edu [Biomedical Engineering Department, Michigan Technological University, Houghton, MI, 49931 (United States)

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg–6%Nd–2%Y–0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd{sub 2}O{sub 3} content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications. - Highlights: • Here we have evaluated the corrosion resistance of a novel Mg alloy (EW62). • Rapid solidification reduces the hydrogen gas evolution and hydrogen embrittlement. • Rapid solidification increases the stress corrosion cracking resistance of EW62. • Improvement is due to enrichment with supersaturated Nd in the external oxide film. • Rapidly solidified and extruded EW62 may serve as a biodegradable medical implant.

  12. Improvement of mechanical properties and corrosion resistance of biodegradable Mg-Nd-Zn-Zr alloys by double extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaobo, E-mail: xbxbzhang2003@163.com [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Wang, Zhangzhong [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Yuan, Guangyin [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, 200240 (China); Xue, Yajun [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Microstructure of Mg-Nd-Zn-Zr alloys was refined and homogenized by double extrusion process. Black-Right-Pointing-Pointer The mechanical properties of the alloys were significantly enhanced by double extrusion. Black-Right-Pointing-Pointer The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg-Nd-Zn-Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg-2.25Nd-0.11Zn-0.43Zr and Mg-2.70Nd-0.20Zn-0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg-Nd-Zn-Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  13. 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.

  14. Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    M.T. Kato

    1997-12-01

    Full Text Available The anaerobic treatment processes are considered to be well-established methods for the elimination of easily biodegradable organic matter from wastewaters. Some difficulties concerning certain wastewaters are related to the possible presence of dissolved oxygen. The common belief is that anaerobes are oxygen intolerant. Therefore, the common practice is to use sequencing anaerobic and aerobic steps in separate tanks. Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. Previous experiments with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges was quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of new applications in wastewater treatment

  15. Degradation of enoxacin antibiotic by the electro-Fenton process: Optimization, biodegradability improvement and degradation mechanism.

    Science.gov (United States)

    Annabi, Cyrine; Fourcade, Florence; Soutrel, Isabelle; Geneste, Florence; Floner, Didier; Bellakhal, Nizar; Amrane, Abdeltif

    2016-01-01

    This study aims to investigate the effectiveness of the electro-Fenton process on the removal of a second generation of fluoroquinolone, enoxacin. The electrochemical reactor involved a carbon-felt cathode and a platinum anode. The influence of some experimental parameters, namely the initial enoxacin concentration, the applied current intensity and the Fe(II) amount, was examined. The degradation of the target molecule was accompanied by an increase of the biodegradability, assessed from the BOD5 on COD ratio, which increased from 0 before treatment until 0.5 after 180 min of electrolysis at 50 mg L(-1) initial enoxacin concentration, 0.2 mmol L(-1) Fe(II) concentration and 300 mA applied current intensity. TOC and COD time-courses were also evaluated during electrolysis and reached maximum residual yields of 54% and 43% after 120 min of treatment, respectively. Moreover, a simultaneous generation of inorganic ions (fluorides, ammonium and nitrates) were observed and 3 short chain carboxylic acids (formic, acetic and oxalic acids) were identified and monitored during 180 min of electrolysis. By-products were identified according to UPLC-MS/MS results and a degradation pathway was proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity

    Science.gov (United States)

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-06-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer.

  17. Plasma treatment for improving cell biocompatibility of a biodegradable polymer scaffold for vascular graft applications.

    Science.gov (United States)

    Valence, Sarra de; Tille, Jean-Christophe; Chaabane, Chiraz; Gurny, Robert; Bochaton-Piallat, Marie-Luce; Walpoth, Beat H; Möller, Michael

    2013-09-01

    Biodegradable synthetic scaffolds are being evaluated by many groups for the application of vascular tissue engineering. In addition to the choice of the material and the structure of the scaffold, tailoring the surface properties can have an important effect on promoting adequate tissue regeneration. The objective of this study was to evaluate the effect of an increased hydrophilicity of a polycaprolactone vascular graft by treatment with a cold air plasma. To this end, treated and untreated scaffolds were characterized, evaluated in vitro with smooth muscle cells, and implanted in vivo in the rat model for 3 weeks, both in the subcutaneous location and as an aortic replacement. The plasma treatment significantly increased the hydrophilicity of the scaffold, with complete wetting after a treatment of 60 sec, but did not change fiber morphology or mechanical properties. Smooth muscle cells cultured on plasma treated patches adopt a spread out morphology compared to a small, rounded morphology on untreated patches. Subcutaneous implantation revealed a low foreign body reaction for both types of scaffolds and a more extended and dense cellular infiltrate in the plasma treated scaffolds. In the vascular position, the plasma treatment induced a better cellularization of the graft wall, while it did not affect endothelialization rate or intimal hyperplasia. Plasma treatment is therefore an accessible tool to easily increase the biocompatibility of a scaffold and accelerate tissue regeneration without compromising mechanical strength, which are valuable advantages for vascular tissue engineering.

  18. Fabrication of genistein-loaded biodegradable TPGS-b-PCL nanoparticles for improved therapeutic effects in cervical cancer cells.

    Science.gov (United States)

    Zhang, Hongling; Liu, Gan; Zeng, Xiaowei; Wu, Yanping; Yang, Chengming; Mei, Lin; Wang, Zhongyuan; Huang, Laiqiang

    2015-01-01

    Genistein is one of the most studied isoflavonoids with potential antitumor efficacy, but its poor water solubility limits its clinical application. Nanoparticles (NPs), especially biodegradable NPs, entrapping hydrophobic drugs have promising applications to improve the water solubility of hydrophobic drugs. In this work, TPGS-b-PCL copolymer was synthesized from ε-caprolactone initiated by d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) through ring-opening polymerization and characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The genistein-loaded NPs were prepared by a modified nanoprecipitation method and characterized in the aspects of particle size, surface charge, morphology, drug loading and encapsulation efficiency, in vitro drug release, and physical state of the entrapped drug. The TPGS-b-PCL NPs were found to have higher cellular uptake efficiency than PCL NPs. MTT and colony formation experiments indicated that genistein-loaded TPGS-b-PCL NPs achieved the highest level of cytotoxicity and tumor cell growth inhibition compared with pristine genistein and genistein-loaded PCL NPs. Furthermore, compared with pristine genistein and genistein-loaded PCL NPs, the genistein-loaded TPGS-b-PCL NPs at the same dose were more effective in inhibiting tumor growth in the subcutaneous HeLa xenograft tumor model in BALB/c nude mice. In conclusion, the results suggested that genistein-loaded biodegradable TPGS-b-PCL nanoparticles could enhance the anticancer effect of genistein both in vitro and in vivo, and may serve as a potential candidate in treating cervical cancer.

  19. Improvement of hydrogen production via ethanol-type fermentation in an anaerobic down-flow structured bed reactor.

    Science.gov (United States)

    Anzola-Rojas, Mélida del Pilar; Zaiat, Marcelo; De Wever, Heleen

    2016-02-01

    Although a novel anaerobic down-flow structured bed reactor has shown feasibility and stable performance for a long-term compared to other anaerobic fixed bed systems for continuous hydrogen production, the volumetric rates and yields have so far been too low. In order to improve the performance, an operation strategy was applied by organic loading rate (OLR) variation (12-96 g COD L(-1) d(-1)). Different volumetric hydrogen rates, and yields at the same OLR indicated that the system was mainly driven by the specific organic load (SOL). When SOL was kept between 3.8 and 6.2 g sucrose g(-1) VSS d(-1), the volumetric rates raised from 0.1 to 8.9 L H2 L(-1) d(-1), and the yields were stable around 2.0 mol H2 mol(-1) converted sucrose. Furthermore, hydrogen was produced mainly via ethanol-type fermentation, reaching a total energy conversion rate of 23.40 kJ h(-1) L(-1) based on both hydrogen and ethanol production.

  20. Improving anaerobic digestion of easy-acidification substrates by promoting buffering capacity using biochar derived from vermicompost.

    Science.gov (United States)

    Wang, Dou; Ai, Jing; Shen, Fei; Yang, Gang; Zhang, Yanzong; Deng, Shihuai; Zhang, Jing; Zeng, Yongmei; Song, Chun

    2017-03-01

    Acid-buffering of VCBC and VC was evaluated using 4 VFAs, and their application on anaerobic digestion of CM and KW was investigated. Results indicated acid-buffering capacity of VCBC to acetic, propionic, butyric, and valeric acid was 2.5, 1.1, 1.9 and 1.6-fold higher comparing with VC. CM digestion was not initiated at higher organic loading of 50gTS/kg, while it worked well with 5.0% VCBC or VC. KW was not digested even though VC or VCBC was increased to 15% and 20%. However, KW digestion can be alleviated with increasing VCBC or VC proportion, in which the alleviation by VCBC was better than VC. Average VFAs concentration during CM digestion with VC was 4077.7mg/L comparing with 2835.8mg/L of VCBC, and biogas release was delayed for 10-days accompanying rapid pH decrease in CM digestion with VC, which reflected acid-buffering of biochar played a crucial role on improving anaerobic digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  2. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  3. Biodegradation Process and Influencing Factors of Azo Using Anaerobic-aerobic Technology%偶氮染料的厌氧-好氧生物降解过程和影响因素

    Institute of Scientific and Technical Information of China (English)

    温贝贝; 刘志刚; 马鲁铭

    2013-01-01

    The total amount and kinds of azo dyes are the biggest of synthetic dyes. Usually the anaerobic-aerobic process is adopted to degrade the azo dyes, for the azo dyes can be reduced to aromatic amines in anaerobic condition, and then degraded completely in the following aerobic condition. Anaerobic reduction process of azo dyes is influenced by the structure and concentration of azo dye, the kind and concentration of substrates, other electron acceptors, redox mediator, environmental parameters such as temperature and dissolved oxygen, and hydraulic retention time. The degradation of aromatic amines under aerobic conditions is affected by its own structure, concentration, additional carbon, degradation system etc. and disturbed by the auto-oxidation of aromatic amines. Good conditions should be provided to improve the azo dyes degradation efficiency of anaerobic-aerobic technology in practical wastewater treatment.%偶氮染料是总量最大、种类最多的合成染料,其降解处理通常采用厌氧-好氧技术.厌氧过程可实现偶氮染料的还原,好氧过程则完成还原产物芳香胺的去除.厌氧过程受偶氮染料结构和浓度、底物的种类和浓度、其他电子受体、氧化还原介体、温度和DO等环境因素以及水力停留时间的影响.好氧条件下芳香胺的降解过程受其自身的结构、浓度、外加碳源以及降解体系等影响,且自氧化过程影响了芳香胺的生物降解.在实际废水处理中应创造良好的条件提高偶氮染料的厌氧-好氧生物降解效率.

  4. Moroccan rock phosphate solubilization during a thermo-anaerobic ...

    African Journals Online (AJOL)

    SWEET

    2013-12-04

    Dec 4, 2013 ... thermo-anaerobic grassland waste biodegradation process. Moussa S. .... plating the nutrient agar isolate on the solid NBRIP medium. (Nautiyal, 1999) ..... solubilizing fungi isolated from phosphate mines. Ecol. Eng. 33:187-.

  5. Life Cycle Assessment of different uses of biogas from anaerobic digestion of separately collected biodegradable waste in France. Final report; Analyse du Cycle de Vie des modes de valorisation energetique du biogaz issu de methanisation de la Fraction Fermentescible des Ordures Menageres collectee selectivement en France. Rapport Final

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    In the first part of the study, Gaz de France (GdF) and the French Environment Energy Management Agency (ADEME) wished to identify the best method to use the biogas from anaerobic digestion of separately collected biodegradable waste (bio-waste). Secondly, GdF and ADEME wished to evaluate the strength and weaknesses of the two main different organic recycling: anaerobic digestion (methanization) and composting. The study is based on the life cycle assessment method. The life cycle assessment used for this study consists in quantifying the environmental impacts of all of the activities which are related to the chosen use method. This methodology involves compiling a detailed account of all substances and energy flows removed or emitted from or into the environment at each stage of the life cycle. These flows are then translated into indicators of potential environment impacts. This methodology is based on the international standards ISO14040 and ISO 14044. The life cycle assessment was performed by RDC Environnement. In this study, two questions were treated: - Which is the best valorisation method for biogas produced from the anaerobic digestion of separately collected biodegradable waste: fuel, heat or electricity? ('Biogas' question); - Which is the best treatment for the separately collected biodegradable waste: anaerobic digestion (methanization) or industrial composting? ('Composting' question). The field of the study includes the arrival of the separately collected biodegradable waste at the anaerobic unit as well as the utilisation of the biogas energy and the agricultural use of the digestate from anaerobic digestion. For each biogas utilisation, the environmental impacts of each life cycle stage were considered as well as the impacts that were avoided due to the substitution of the use of non-renewable energy ('conventional' procedures). The modelling of the direct composting of the biodegradable waste was realised taking into

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

    Science.gov (United States)

    Jin, Yiying; Li, Yangyang; Li, Jinhui

    2016-09-15

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

  7. Review of feedstock pretreatment strategies for improved anaerobic digestion: From lab-scale research to full-scale application.

    Science.gov (United States)

    Carrere, Hélène; Antonopoulou, Georgia; Affes, Rim; Passos, Fabiana; Battimelli, Audrey; Lyberatos, Gerasimos; Ferrer, Ivet

    2016-01-01

    When properly designed, pretreatments may enhance the methane potential and/or anaerobic digestion rate, improving digester performance. This paper aims at providing some guidelines on the most appropriate pretreatments for the main feedstocks of biogas plants. Waste activated sludge was firstly investigated and implemented at full-scale, its thermal pretreatment with steam explosion being most recommended as it increases the methane potential and digestion rate, ensures sludge sanitation and the heat needed is produced on-site. Regarding fatty residues, saponification is preferred for enhancing their solubilisation and bioavailability. In the case of animal by-products, this pretreatment can be optimised to ensure sterilisation, solubilisation and to reduce inhibition linked to long chain fatty acids. With regards to lignocellulosic biomass, the first goal should be delignification, followed by hemicellulose and cellulose hydrolysis, alkali or biological (fungi) pretreatments being most promising. As far as microalgae are concerned, thermal pretreatment seems the most promising technique so far.

  8. Improving the stability of thermophilic anaerobic digesters treating SS-OFMSW through enrichment with compost and leachate seeds

    KAUST Repository

    Ghanimeh, Sophia A.

    2013-03-01

    This paper examines the potential of improving the stability of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) by adding leachate and compost during inoculation. For this purpose, two stable thermophilic digesters, A (control) and B (with added leachate and compost), were subjected to a sustained substrate shock by doubling the organic loading rate for one week. Feeding was suspended then gradually resumed to reach the pre-shock loading rate (2. gVS/l/d). Digester A failed, exhibiting excessive increase in acetate and a corresponding decrease in pH and methane generation, and lower COD and solids removal efficiencies. In contrast, digester B was able to restore its functionality with 90% recovery of pre-shock methane generation rate at stable pH, lower hydrogen levels, and reduced VFAs and ammonia accumulation. © 2012 Elsevier Ltd.

  9. Biodegradation improvement of poly(3-hydroxy-butyrate) films by entomopathogenic fungi and UV-assisted surface functionalization.

    Science.gov (United States)

    Kessler, Felipe; Marconatto, Leticia; Rodrigues, Roberta da Silva Bussamara; Lando, Gabriela Albara; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

    2014-01-05

    Ultraviolet (UV)-assisted surface modification in the presence of oxygen was used as initial step to achieve controlled degradation of poly(3-hydroxy-butyrate), PHB, films by entomopathogenic fungi. Treated surfaces were investigated by surface analysis techniques (water contact angle, Fourier Transformed Infrared Spectroscopy in Attenuated Total Reflectance mode, X-ray Photoelectron Spectroscopy, Near-edge X-ray Absorption Fine Structure, Gel Permeation Chromatography, Optical Microscopy, Scanning Electron Microscopy, and weight loss). After the UV-assisted treatments, new carbonyl groups in new chemical environments were detected by XPS and NEXAFS spectroscopy. The oxidizing atmosphere did not allow the formation of CC bonds, indicating that Norrish Type II mechanism is suppressed during or by the treatments. The higher hydrophilicity and concentration of oxygenated functional groups at the surface of the treated films possibly improved the biodegradation of the films. It was observed a clear increase in the growth of this fungus when oxygenated groups were grafted on the polymers surfaces. This simple methodology can be used to improve and control the degradation rate of PHB films in applications that require a controllable degradation rate.

  10. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes.

    Science.gov (United States)

    Hakimi, O; Aghion, E; Goldman, J

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg-6%Nd-2%Y-0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd2O3 content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications.

  11. Reducing agitation energy-consumption by improving rheological properties of corn stover substrate in anaerobic digestion.

    Science.gov (United States)

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

    2014-09-01

    Rheological properties of corn stover substrate were investigated to explore agitation energy reduction potential for different total solid (TS) in anaerobic digestion. The effects of particle size and temperature on rheological properties and corresponding energy reduction were studied. The results indicated that corn stover slurry exhibited pseudo-plastic flow behavior at TS of 4.23-7.32%, and was well described by Power-law model. At TS of 4.23%, rheological properties were not obviously affected by particle size and temperature. However, when TS was increased to 7.32%, there was 10.37% shear stress reduction by size-reduction from 20 to 80-mesh, and 11.73% shear stress reduction by temperature-increase from 25 to 55 °C. PTS was advanced as variations of power consumption by TS-increase from 4.23% to 7.32%. There was 9.2% PTS-reduction by size-reduction from 20 to 80-mesh at 35 °C. Moreover, PTS-reduction of 10.3%/10 °C was achieved at 20-mesh compared with 9.0%/10 °C at 80-mesh.

  12. 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)

  13. Biodegradable intestinal stents:A review

    Institute of Scientific and Technical Information of China (English)

    Zhanhui Wang; Nan Li; Rui Li; Yawei Li; Liqun Ruan

    2014-01-01

    Biodegradable stents are an attractive alternative to self-expanding metal stents in the treatment of intestinal strictures. Biodegradable stent can be made of biodegradable polymers and biodegradable metals (magnesium alloys). An overview on current biodegradable intestinal stents is presented. The future trends and perspectives in the development of biodegradable intestinal stents are proposed. For the biodegradable polymer intestinal stents, the clinical trials have shown promising results, although improved design of stents and reduced migration rate are expected. For the biodegradable magnesium intestinal stents, results of preliminary studies indicate magnesium alloys to have good biocompatibility. With many of the key fundamental and practical issues resolved and better methods for adjusting corrosion resistance and progressing biocompatibilities of magnesium alloys, it is possible to use biodegradable intestinal stents made of magnesium alloys in hospital in the not too distant future.

  14. ANAEROBIC-AEROBIC TREATMENT OF TEXTILE WASTEWATER IN A SEQUENCING BATCH REACTOR

    Directory of Open Access Journals (Sweden)

    IBTISSAM KANBOUCHI

    2014-04-01

    Full Text Available In this work, the treatment of synthetic textile wastewater using sequential batch reactor (SBR was studied. This in order to predict the effectiveness of biological treatment on wastewater containing dyes while minimizing the aeration cost. Laboratory tests were performed on synthetic wastewater containing filtered urban wastewater (source of bacteria and dyes solutions. This promotes the biomass development in the mixture, capable of degrading organic matter properly. The results indicate that the increasing of anaerobic phase (16 hours allows removal of 77 % and 80 % of COD and colour, respectively. The sludge age did not affect markedly dyes biodegradability. However, the biodegradability is strongly influenced by the dyes concentration. Indeed, for the lowest dyes contents, improved biodegradability was observed, while it decreases when the dyes concentration increases.

  15. Intermittent hypoxic training improves anaerobic performance in competitive swimmers when implemented into a direct competition mesocycle.

    Science.gov (United States)

    Czuba, Miłosz; Wilk, Robert; Karpiński, Jakub; Chalimoniuk, Małgorzata; Zajac, Adam; Langfort, Józef

    2017-01-01

    The main objective of this research was to evaluate the efficacy of intermittent hypoxic training (IHT) on anaerobic and aerobic capacity and swimming performance in well-trained swimmers. Sixteen male swimmers were randomly divided into a hypoxia (H) group (n = 8), which trained in a normobaric hypoxia environment, and a control (C) group (n = 8), which exercised under normoxic conditions. However, one participant left the study without explanation. During the experiment group H trained on land twice per week in simulated hypoxia (FiO2 = 15.5%, corresponding to 2,500 m a.s.l); however, they conducted swim training in normoxic conditions. Group C performed the same training program under normoxic conditions. The training program included four weekly microcyles, followed by three days of recovery. During practice sessions on land, the swimmers performed 30 second sprints on an arm-ergometer, alternating with two minute high intensity intervals on a lower limb cycle ergometer. The results showed that the training on land caused a significant (pvalues of VO2max by 6.9% in group H and 3.7% in group C. However, absolute values of VO2max were not significantly changed. Additionally, a significant (pvalues of lactate concentration (ΔLA) after both Wingate tests were significantly (pvalues of blood pH (ΔpH) after both Wingate tests in group H, with a significant decrease in values of ΔpH by 33.3%. The IHT caused a significant (pTraining in normoxia (group C), resulted in a significant (ptraining protocol had no effect on absolute values of VO2max and hematological variables.

  16. Anaerobic fermentation of agricultural residue: potential for improvement and implementation. Final report, Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, W. J.; Dell' orto, S.; Fanfoni, K. J.; Hayes, T. D.; Leuschner, A. P.; Sherman, D. F.

    1980-04-01

    Earlier studies have shown that although large quantities of agricultural residues are generated on small farms, it was difficult to economically justify use of conventional anaerobic digestion technology, such as used for sewage sludge digestion. A simple, unmixed, earthen-supported structure appeared to be capable of producing significant quantities of biogas at a cost that would make it competitive with many existing fuels. The goal of this study was to define and demonstrate a methane fermentation technology that could be practical and economically feasible on small farms. This study provides the first long term, large scale (reactor volumes of 34 m/sup 3/) parallel testing of the major theory, design, construction, and operation of a low cost approach to animal manure fermentation as compared to the more costly and complex designs. The main objectives were to define the lower limits for successful fermentor operation in terms of mixing, insulation, temperature, feed rate, and management requirements in a cold climate with both pilot scale and full scale fermentors. Over a period of four years, innovative fermentation processes for animal manures were developed from theoretical concept to successful full scale demonstration. Reactors were sized for 50 to 65 dairy animals, or for the one-family dairy size. The results show that a small farm biogas generation system that should be widely applicable and economically feasible was operated successfully for nearly two years. Although this low cost system out-performed the completely mixed unit throughout the study, perhaps the greatest advantage of this approach is its ease of modification, operation, and maintenance.

  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. Fabrication of genistein-loaded biodegradable TPGS-b-PCL nanoparticles for improved therapeutic effects in cervical cancer cells

    Directory of Open Access Journals (Sweden)

    Zhang H

    2015-03-01

    Full Text Available Hongling Zhang,1,2* Gan Liu,1,2* Xiaowei Zeng,1,2 Yanping Wu,1,2 Chengming Yang,3 Lin Mei,1,2 Zhongyuan Wang,2,4 Laiqiang Huang1,2 1School of Life Sciences, Tsinghua University, Beijing, People’s Republic of China; 2The Shenzhen Key Laboratory of Gene and Antibody Therapy, Center for Biotechnology and Biomedicine and Division of Life and Health Sciences, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong, People’s Republic of China; 3Xili Hospital, Shenzhen, Guangdong, People’s Republic of China; 4School of Medicine, Shenzhen University, Shenzhen, People’s Republic of China *These authors contributed equally to this work Abstract: Genistein is one of the most studied isoflavonoids with potential antitumor efficacy, but its poor water solubility limits its clinical application. Nanoparticles (NPs, especially biodegradable NPs, entrapping hydrophobic drugs have promising applications to improve the water solubility of hydrophobic drugs. In this work, TPGS-b-PCL copolymer was synthesized from ε-caprolactone initiated by d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS through ring-opening polymerization and characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The genistein-loaded NPs were prepared by a modified nanoprecipitation method and characterized in the aspects of particle size, surface charge, morphology, drug loading and encapsulation efficiency, in vitro drug release, and physical state of the entrapped drug. The TPGS-b-PCL NPs were found to have higher cellular uptake efficiency than PCL NPs. MTT and colony formation experiments indicated that genistein-loaded TPGS-b-PCL NPs achieved the highest level of cytotoxicity and tumor cell growth inhibition compared with pristine genistein and genistein-loaded PCL NPs. Furthermore, compared with pristine genistein and genistein-loaded PCL NPs

  19. Extracellular polymeric substances govern the development of biofilm and mass transfer of polycyclic aromatic hydrocarbons for improved biodegradation.

    Science.gov (United States)

    Zhang, Yinping; Wang, Fang; Zhu, Xiaoshu; Zeng, Jun; Zhao, Qiguo; Jiang, Xin

    2015-10-01

    The hypothesis that extracellular polymeric substances (EPS) affect the formation of biofilms for subsequent enhanced biodegradation of polycyclic aromatic hydrocarbons was tested. Controlled formation of biofilms on humin particles and biodegradation of phenanthrene and pyrene were performed with bacteria and EPS-extracted bacteria of Micrococcus sp. PHE9 and Mycobacterium sp. NJS-P. Bacteria without EPS extraction developed biofilms on humin, in contrast the EPS-extracted bacteria could not attach to humin particles. In the subsequent biodegradation of phenanthrene and pyrene, the biodegradation rates by biofilms were significantly higher than those of EPS-extracted bacteria. Although, both the biofilms and EPS-extracted bacteria showed increases in EPS contents, only the EPS contents in biofilms displayed significant correlations with the biodegradation efficiencies of phenanthrene and pyrene. It is proposed that the bacterial-produced EPS was a key factor to mediate bacterial attachment to other surfaces and develop biofilms, thereby increasing the bioavailability of poorly soluble PAH for enhanced biodegradation.

  20. Improved corneal bioavailability of ofloxacin: biodegradable microsphere-loaded ion-activated in situ gel delivery system

    Science.gov (United States)

    Sayed, Elshaimaa G; Hussein, Amal K; Khaled, Khaled A; Ahmed, Osama AA

    2015-01-01

    The aim of the study was to improve corneal penetration and bioavailability of ofloxacin (OFX) eye preparations. OFX was incorporated in poly (lactide-co-glycolide) as biodegradable microspheres using oil in oil emulsion solvent evaporation technique. The prepared OFX microspheres were then incorporated in Gelrite® in situ gel preparation. In addition, OFX Gelrite-based in situ gel formulations were prepared. OFX formulations were characterized for gelling capacity, viscosity, and rheological properties. Release studies for OFX microspheres, OFX in situ gel, and OFX-loaded microspheres in situ gel formulations were carried out to investigate release characteristics of the drug. The prepared OFX formulations were then investigated in vivo compared with commercially available OFX eyedrops. Results showed that the optimum Gelrite concentration was at 0.4%–0.7% w/v; the prepared formulations were viscous liquid transformed into a pourable gel immediately after the addition of simulated tear fluid with a gelling factor of 27–35. Incorporation of OFX-loaded microspheres in Gelrite solution (0.4% w/v) significantly altered the release profiles of OFX-loaded microspheres in situ gel formula compared with the corresponding OFX gels and OFX microspheres. In vivo results in rabbits showed that OFX-loaded microspheres in situ gel formula improved the relative bioavailability by 11.7-fold compared with the commercially available OFX eyedrops. In addition, the longer duration of action of OFX-loaded microspheres in situ gel formula preparations is thought to avoid frequent instillations, which improves patient tolerability and compliance. PMID:25792803

  1. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  2. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  3. Thermophilic anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor.

    Science.gov (United States)

    Wang, Wei; Ma, Wencheng; Han, Hongjun; Li, Huiqiang; Yuan, Min

    2011-02-01

    Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35±2°C) reactor as a control, thermophilic anaerobic digestion (55±2°C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m(3) d) and HRT of 24 h; the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pretreatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW.

  4. Biodegradable polymer brush as nanocoupled interface for improving the durability of polymer coating on metal surface.

    Science.gov (United States)

    Bedair, Tarek M; Cho, Youngjin; Joung, Yoon Ki; Han, Dong Keun

    2014-10-01

    Metal-based drug-eluting stents (DESs) have severe drawbacks such as peeling-off and cracking of the coated polymer. To prevent the fracture of polymer-coated layer and improve the durability of DES, poly(l-lactide) (PLLA) brushes were synthesized onto cobalt-chromium (Co-Cr or CC) surface through atom transfer radical polymerization (ATRP) of 2-hydroxyethylmethacrylate (HEMA) followed by surface-initiated ring opening polymerization (SI-ROP) of l-lactide. The polymer brushes were then characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR), water contact angle, ellipsometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All of the unmodified and modified Co-Cr surfaces were coated with a matrix of poly(d,l-lactide) (PDLLA) and sirolimus (SRL). The in vitro drug release profile was measured for 70 days. The PLLA-modified Co-Cr showed a biphasic release pattern in the initial burst followed by a slow release. On the other hand, the unmodified Co-Cr showed fast drug release and detachment of the coated polymer layer due to the instability of the polymer layer on Co-Cr surface. In comparison, the PLLA-modified Co-Cr preserved a uniform coating without detachment even after 6 weeks of degradation test. The platelet morphology and low density of platelet adhered on the modified layer and the SRL-in-PDLLA coated Co-Cr surfaces demonstrated that these samples would be blood compatible. Therefore, the introduction of PLLA brush onto Co-Cr surface is proved to dramatically improve the durability of the coating layer, and it is a promising strategy to prevent the coating defects found in DESs.

  5. Novel method to improve vascularization of tissue engineered constructs with biodegradable fibers.

    Science.gov (United States)

    Wong, Hui Kian; Ivan Lam, Chee Ren; Wen, Feng; Mark Chong, Seow Khoon; Tan, Nguan Soon; Jerry, Chan; Pal, Mintu; Tan, Lay Poh

    2016-01-07

    Tissue engineered grafts lack adequate vascularization and suffer from poor perfusion in vivo curtailing clinical application. Improving vascularization in any tissue implants would hence increase their survivability and treatment efficacy. Many prevascularization strategies established to date involves the angiogenic induction of endothelial progenitor cells in thick tissue engineered scaffolds to obtain vascularization. These 3D scaffolds typically require a dynamic cell culturing system involving/needful of bioreactors to obtain vascularization in thick tissue engineered scaffolds. Herein, we developed a novel method to engineer a vessel network without bioreactor, where 3D blood vessels could be simply obtained in a 2D static cell culturing system. This network could be used to augment the prevascularization of tissue engineered grafts. Endothelial cells (HUVECs) were confluently cultured on resorbable electrospun poly (D, L-lactide-co-glycolide) microfibers of capillary dimensions. These cell encapsulated capillary fibers were further embedded in collagen with HUVECs and vascular endothelial growth factor. Green fluorescent protein and red fluorescent protein expressing HUVECs were used to label cells on fiber and in collagen respectively for visualization and monitoring of capillary network formation. Seeded HUVECs in the hybrid construct were subsequently cultured for 30 days before implantation. Vessel density was measured by the total tubule length per unit area at different time points. In vitro results indicated that the fibers provide contact guidance to form primary networks to direct more vessels branching of HUVECs in hybrid constructs and the vessel integrity of microvasculature was retained after fiber degradation. In addition, these preformed engineered capillaries could capably inosculate with de novo capillaries in collagen when combined, giving rise to a hybrid pre-vascularized scaffold of more extensive vessel network and interconnections

  6. A new iron calcium phosphate material to improve the osteoconductive properties of a biodegradable ceramic: a study in rabbit calvaria.

    Science.gov (United States)

    Manchón, Angel; Hamdan Alkhraisat, Mohammad; Rueda-Rodriguez, Carmen; Prados-Frutos, Juan Carlos; Torres, Jesús; Lucas-Aparicio, Julia; Ewald, Andrea; Gbureck, Uwe; López-Cabarcos, Enrique

    2015-10-20

    β-tricalcium phosphate (β-TCP) is an osteoconductive and biodegradable material used in bone regeneration procedures, while iron has been suggested as a tool to improve the biological performance of calcium phosphate-based materials. However, the mechanisms of interaction between these materials and human cells are not fully understood. In order to clarify this relationship, we have studied the iron role in β-TCP ceramics. Iron-containing β-TCPs were prepared by replacing CaCO3 with C6H5FeO7 at different molar ratios. X-ray diffraction analysis indicated the occurrence of β-TCP as the sole phase in the pure β-TCP and iron-containing ceramics. The incorporation of iron ions in the β-TCP lattice decreased the specific surface area as the pore size was shifted toward meso- and/or macropores. Furthermore, the human osteoblastlike cell line MG-63 was cultured onto the ceramics to determine cell proliferation and viability, and it was observed that the iron-β-TCP ceramics have better cytocompatibility than pure β-TCP. Finally, in vivo assays were performed using rabbit calvaria as a bone model. The scaffolds were implanted for 8 and 12 weeks in the defects created in the skullcap with pure β-TCP as the control. The in vivo behavior, in terms of new bone formed, degradation, and residual graft material were investigated using sequential histological evaluations and histomorphometric analysis. The in vivo implantation of the ceramics showed enhanced bone tissue formation and scaffold degradation for iron-β-TCPs. Thus, iron appears to be a useful tool to enhance the osteoconductive properties of calcium phosphate ceramics.

  7. Improving methane production and phosphorus release in anaerobic digestion of particulate saline sludge from a brackish aquaculture recirculation system.

    Science.gov (United States)

    Zhang, Xuedong; Ferreira, Rui B; Hu, Jianmei; Spanjers, Henri; van Lier, Jules B

    2014-06-01

    In this study, batch tests were conducted to examine the effects of trehalose and glycine betaine as well as potassium on the specific methanogenic activity (SMA), acid and alkaline phosphatase activity of anaerobic biomass and phosphorus release in anaerobic digestion of saline sludge from a brackish recirculation aquaculture system. The results of ANOVA and Tukey's HSD (honestly significant difference) tests showed that glycine betaine and trehalose enhanced SMA of anaerobic biomass and reactive phosphorus release from the particulate waste. Moreover, SMA tests revealed that methanogenic sludge, which was long-term acclimatized to a salinity level of 17 g/L was severely affected by the increase in salinity to values exceeding 35 g/L. Addition of compatible solutes, such as glycine betaine and trehalose, could be used to enhance the specific methane production rate and phosphorus release in anaerobic digestion from particulate organic waste produced in marine or brackish aquaculture recirculation systems.

  8. Anaerobic fermentation of agricultural residues: potential for improvement and implementation. Seventh quarter progress report, December 16, 1977--March 15, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, W.J.; Guest, R.W.; Loehr, R.C.; Price, D.R.; Gunkel, W.W.; Van Soest, P.J.

    1978-01-01

    This is the seventh progress report of an on-going three year research effort to contribute to the development of a new and/or improved technology that will result in wide spread use of an anaerobic fermentation in agriculture to generate a renewable clean energy source. Activities are now concentrating on full-scale and pilot-scale demonstration of simplified fermentors for manures. Activities for the seventh quarter year, extending from December 16, 1977 to March 15, 1978, have included the following: completion of construction of the full scale conventional control fermenter; completion of construction, testing and startup of the random mix fermenter; installation of feed and effluent lines, electrical wiring, boilers, gas lines and controls; successful testing of the ram pump; conclusion of the 35/sup 0/C studies with the pilot scale plug flow fermenter and the initiation of the low temperature (25/sup 0/C) studies; and preparation of a detailed outline to the design manual. As of March 15, 1978, the overall progress achieved with the major components of the project was estimated to be about 2.5 months behind the work plan schedule. As detailed in the last progress report, much of this delay has been due to the winter weather (i.e., cold temperatures, snow, frozen ground, etc.) which has interfered with excavation and other outdoor construction activities.

  9. Improve biogas production from low-organic-content sludge through high-solids anaerobic co-digestion with food waste.

    Science.gov (United States)

    Liu, Chuanyang; Li, Huan; Zhang, Yuyao; Liu, Can

    2016-11-01

    Anaerobic co-digestion of sewage sludge and food waste was tested at two different total solid (TS) concentrations. In the low-solids group with TS 4.8%, the biogas production increased linearly as the ratio of food waste in substrate increased from 0 to 100%, but no synergetic effect was found between the two substrates. Moreover, the additive food waste resulted in the accumulation of volatile fatty acids and decelerated biogas production. Thus, the blend ratio of food waste should be lower than 50%. While in the high-solids group with TS 14%, the weak alkaline environment with pH 7.5-8.5 avoided excessive acidification but high concentration of free ammonia was a potential risk. However, good synergetic effect was found between the two substrates because the added food waste improved mass transfer in sludge cake. Thus, 50% was recommended as the optimum ratio of food waste in substrate because of the best synergetic effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Editorial: Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Carl Schaschke

    2014-11-01

    Full Text Available This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment.

  11. Avaliação da biodegradabilidade anaeróbia de resíduos da bovinocultura e da suinocultura Anaerobic biodegradability of wastewater from dairy and swine

    Directory of Open Access Journals (Sweden)

    Luciana M. Moraes

    2004-08-01

    Full Text Available A biodegradabilidade de dejetos da bovinocultura e da suinocultura foi avaliada por meio de metodologia simplificada que permitiu a verificação da aplicabilidade de processos anaeróbios. Os ensaios foram realizados com reatores em batelada, com lodos granulados de três procedências: reator UASB tratando efluente de bovinocultura, reator UASB tratando efluente de suinocultura e reator UASB tratando efluente de abatedouro de aves. Os ensaios (1 - efluente de bovinocultura e lodo de abatedouro de aves não-adaptado; (2 - efluente de suinocultura e lodo de abatedouro de aves não- adaptado; (3 - efluente de bovinocultura e lodo de abatedouro de aves adaptado; (4 - efluente de suinocultura e lodo de abatedouro de aves adaptado; (5 - efluente de bovinocultura e lodo de bovinocultura, e (6 - efluente de suinocultura e lodo de suinocultura realizados em "Shaker", em temperatura de 35 °C, sob agitação a 150 rpm, por 5 minutos a cada 1 hora. Foi utilizada uma relação de substrato:biomassa igual a 0,5. Foram testados modelos cinéticos do tipo Monod, Ordem Zero, Primeira e Segunda Ordens e verificou-se que o modelo de Primeira Ordem foi o que melhor se ajustou para os seis ensaios realizados. A constante de velocidade de Primeira Ordem (k1 foi estimada para os ensaios 1; 2; 3; 4; 5 e 6, resultando 2,51 x 10-2; 2,49 x 10-2; 1,90 x 10-2; 3,09 x 10-2; 2,54 x 10-2, e 4,09 x 10-2 h-1, respectivamente.The biodegradability of animal wastes production was evaluated through a simplified methodology that allowed the verification of the applicability of anaerobic processes. The experiments were performed in bath reactors, with granular sludge of three origins: UASB reactor treating dairy effluent, UASB reactor treating swine effluent and UASB reactor treating effluent of slaughterhouse of poultry. The experiments (1 - dairy effluent and poultry slaughterhouse non-adapted sludge; (2 -swine effluent and poultry slaughterhouse non-adapted sludge; (3 - dairy

  12. Anaerobic degradation of linear alkylbenzene sulfonate.

    Science.gov (United States)

    Mogensen, Anders S; Haagensen, Frank; Ahring, Birgitte K

    2003-04-01

    Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C12 LAS), which show that C12 LAS was biodegradable under methanogenic conditions. Sorption of C12 LAS on sewage sludge was described with a Freundlich isotherm. The C12 LAS sorption was determined with different concentrations of total solids (TS). In the semi-continuously stirred tank reactor, 18% of the added C12 LAS was bioavailable and 20% was biotransformed when spiking with 100 mg/L of C12 LAS and a TS concentration of 14.2 mg/L. Enhanced bioavailability of C12 LAS was obtained in an upflow anaerobic sludge blanket (UASB) reactor inoculated with granular sludge and sewage sludge. Biodegradation under thermophilic conditions was 37% with LAS as sole carbon source. Benzaldehyde was produced in the UASB reactor during LAS transformation.

  13. The anaerobic co-digestion of sheep bedding and ⩾ 50% cattle manure increases biogas production and improves biofertilizer quality.

    Science.gov (United States)

    Cestonaro, Taiana; Costa, Mônica Sarolli Silva de Mendonça; Costa, Luiz Antônio de Mendonça; Rozatti, Marcos Antonio Teofilo; Pereira, Dercio Ceri; Lorin, Higor Eisten Francisconi; Carneiro, Leocir José

    2015-12-01

    Sheep manure pellets are peculiarly shaped as small 'capsules' of limited permeability and thus are difficult to degrade. Fragmentation of manure pellets into a homogeneous mass is important for decomposition by microorganisms, and occurs naturally by physical shearing due to animal trampling, when sheep bedding is used. However, the high lignocellulose content of sheep bedding may limit decomposition of sheep manure. Here, we evaluated if co-digestion of sheep bedding with cattle manure would improve the yield and quality of the useful products of anaerobic digestion of sheep bedding--biogas and biofertilizer--by providing a source of nutrients and readily available carbon. Mixtures of sheep bedding and cattle manure in varying proportions (0%, 25%, 50%, 75%, or 100% cattle manure) were added to 6-L digesters, used in a batch system, and analyzed by uni and multivariate statistical tools. PC1, which explained 64.96% of data variability, can be referred to as 'organic fraction/productivity', because higher rates of organic fraction consumption (COD, cellulose and hemicellulose contents) led to higher digester productivity (biogas production, nutrient concentration, and sample stability changes). Therefore, productivity and organic fraction variables were most influenced by manure mixtures with higher (⩾ 50%) or lower (⩽ 25%) ratios of cattle manure, respectively. Increasing the amount of cattle manure up to 50% enhanced the biogas potential production from 142 L kg(-1)TS (0% of cattle manure) to 165, 171, 160 L biogas kg(-1)TS for the mixtures containing 100%, 75% and 50% of cattle manure, respectively. Our results show that the addition of ⩾ 50% cattle manure to the mixture increases biogas production and improves the quality of the final biofertilizer.

  14. Improving the energy balance of grass-based anaerobic digestion through harvesting optimization

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Egelund, H.

    to determine the treatment with the best energy balance, the energy demand during harvesting was compared to the practical methane yield. The biomethanation process was evaluated using triplicate batch assays under thermophilic conditions following the guidelines of the biochemical methane potential (BMP...... that the appropriate harvester can improve the energy output by approximately 2.4 GJ/ha under optimal conditions and subsequently, the overall sustainability of grass-based AD....... efficiency is still doubted and thus, they are not widely used in full-scale biogas plants. In addition, these methods are typically associated with increased costs or energy demands. Hence, there is a need to find effective and cost-efficient solutions that boost biomass decomposition. In this concept, one...

  15. 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.

  16. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  17. Oil biodegradation

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Langenhoff, Alette A.M.; Smit, Martijn P.J.; Eenennaam, van Justine S.; Murk, Tinka; Rijnaarts, Huub H.M.

    2017-01-01

    During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study

  18. Understanding the removal mechanisms of PPCPs and the influence of main technological parameters in anaerobic UASB and aerobic CAS reactors

    Energy Technology Data Exchange (ETDEWEB)

    Alvarino, T., E-mail: teresa.alvarino@usc.es; Suarez, S., E-mail: Sonia.suarez@usc.es; Lema, J.M., E-mail: juan.lema@usc.es; Omil, F., E-mail: francisco.omil@usc.es

    2014-08-15

    Highlights: • Removals of 16 PPCPs under aerobic and anaerobic conditions were quantified. • Operation conditions (HRT, v{sub up}, biomass activity and conformation) influenced removal. • Highest removals associated to aerobic biodegradation. • Sorption was only relevant for lipophilic compounds in the UASB reactor. - Abstract: The removal of 16 Pharmaceutical and Personal Care Products (PPCPs) were studied in a conventional activated sludge (CAS) unit and an upflow anaerobic sludge blanket (UASB) reactor. Special attention was paid to each biomass conformation and activity as well as to operational conditions. Biodegradation was the main PPCP removal mechanism, being higher removals achieved under aerobic conditions, except in the case of sulfamethoxazole and trimetrophim. Under anaerobic conditions, PPCP biodegradation was correlated with the methanogenic rate, while in the aerobic reactor a relationship with nitrification was found. Sorption onto sludge was influenced by biomass conformation, being only significant for musk fragrances in the UASB reactor, in which an increase of the upward velocity and hydraulic retention time improved this removal. Additionally, PPCP sorption increased with time in the UASB reactor, due to the granular biomass structure which suggests the existence of intra-molecular diffusion.

  19. 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)

  20. The anaerobic endurance of elite soccer players improved after a high-intensity training intervention in the 8-week conditioning program.

    Science.gov (United States)

    Sporis, Goran; Ruzic, Lana; Leko, Goran

    2008-03-01

    The purpose of this study was to evaluate changes in anaerobic endurance in elite First-league soccer players throughout 2 consecutive seasons, in 2 phases, with and without high-intensity situational drills. Eighteen soccer players were tested before and after the 8-week summer conditioning and again in the next season. The measured variables included 300-yard shuttle run test, maximal heart rate, and maximal blood lactate at the end of the test. During the first phase of the study, the traditional sprint training was performed only 2 x weeks and consisted of 15 bouts of straight-line sprinting. In the second year the 4 x 4 min drills at an intensity of 90-95% of HRmax, separated by periods of 3-minute technical drills at 55-65% of HRmax were introduced. Statistical significance was set at P sprinting in improving anaerobic endurance measured by the 300-yard shuttle run test.

  1. Steam explosion pretreatment of wheat straw to improve methane yields: investigation of the degradation kinetics of structural compounds during anaerobic digestion.

    Science.gov (United States)

    Theuretzbacher, Franz; Lizasoain, Javier; Lefever, Christopher; Saylor, Molly K; Enguidanos, Ramon; Weran, Nikolaus; Gronauer, Andreas; Bauer, Alexander

    2015-03-01

    Wheat straw can serve as a low-cost substrate for energy production without competing with food or feed production. This study investigated the effect of steam explosion pretreatment on the biological methane potential and the degradation kinetics of wheat straw during anaerobic digestion. It was observed that the biological methane potential of the non steam exploded, ground wheat straw (276 l(N) kg VS(-1)) did not significantly differ from the best steam explosion treated sample (286 l(N) kg VS(-1)) which was achieved at a pretreatment temperature of 140°C and a retention time of 60 min. Nevertheless degradation speed was improved by the pretreatment. Furthermore it was observed that compounds resulting from chemical reactions during the pretreatment and classified as pseudo-lignin were also degraded during the anaerobic batch experiments. Based on the rumen simulation technique, a model was developed to characterise the degradation process.

  2. Central treatment of different emulsion wastewaters by an integrated process of physicochemically enhanced ultrafiltration and anaerobic-aerobic biofilm reactor.

    Science.gov (United States)

    Zhang, Weijun; Xiao, Ping; Wang, Dongsheng

    2014-05-01

    The feasibility of an integrated process of ultrafiltration (UF) enhanced by combined chemical emulsion breaking with vibratory shear and anaerobic/aerobic biofilm reactor for central treatment of different emulsion wastewaters was investigated. Firstly, it was found that calcium chloride exhibited better performance in oil removal than other inorganic salts. Chemical demulsification pretreatment could efficiently improve oil removal and membrane filtration in emulsion wastewater treatment by VSEP. According to aerobic batch bioassay, UF permeate exhibited good biodegradability and could be further treated with biological process. Additionally, pilot test indicated that anaerobic-aerobic biofilm exhibited an excellent ability against rise in organic loading and overall chemical oxygen demand (COD) removal efficiency of biological system was more than 93% of which 82% corresponded to the anaerobic process and 11% to the aerobic degradation. The final effluent of integrated process could meet the "water quality standards for discharge to municipal sewers" in China.

  3. Synthesis of E7 peptide-modified biodegradable polyester with the improving affinity to mesenchymal stem cells.

    Science.gov (United States)

    Li, Qian; Xing, Dongming; Ma, Lie; Gao, Changyou

    2017-04-01

    As the most promising stem cell, bone marrow-derived mesenchymal stem cells (BMSCs) has attracted many attentions and applied widely in regenerative medicine. A biodegradable polyester with tunable affinity to BMSCs plays critical role in determining the properties of the BMSCs-based constructs. In this study, maleimide functionalized biodegradable polyester (P(MTMC-LA)) was synthesized through ring-opening copolymerization between l-lactide (LA) and furan-maleimide functionalized trimethylene carbonate (FMTMC) and a subsequent retro Diels-Alder reaction. P(MTMC-LA) was modified by different amounts of BMSCs specific affinity peptide (EPLQLKM, E7) through click-chemistry to investigate the effect on BMSCs. The E7 peptide modified P(MTMC-LA) was casted into films on glass slides and BMSCs were seeded onto the films. In vitro study showed that E7 peptide modified P(MTMC-LA) films supported BMSCs adhesion and proliferation compared to unmodified P(MTMC-LA) film. Besides, the adhesion and proliferation were enhanced by the increasing peptide grafting ratio. These results indicated that the novel biodegradable polyester can serve as a biomaterial with great potential application in tissue engineering and regenerative medicine.

  4. Anaerobic protozoa and their growth in biomethanation systems.

    Science.gov (United States)

    Priya, M; Haridas, Ajit; Manilal, V B

    2008-04-01

    This study was to investigate growth of protozoa and its influence on biodegradation in anaerobic treatment systems. It was done by specifically controlling and monitoring growth of protozoa versus degradation in continuous stirred anaerobic reactors and batch anaerobic reactors. Occurrence of a diverse protozoa population such as the ciliates, Prorodon, Vorticella, Cyclidium, Spathidium, Loxodes, Metopus were observed in stable anaerobic systems and the flagellates, Rhynchomonas, Naeglaria, Amoeboflagellates, Tetramitus, Trepomonas and Bodo during increased VFA concentration and affected periods of biomethanation. The abundance of ciliates in the anaerobic system had significant correlation with the reduction of MLSS, increased rate of COD removal and higher methane production. The results of this study thus tend to relate increased anaerobic degradation with the abundance of protozoa, mainly ciliates, which indicate their possible involvement in the process. Present study also reveals that performance of anaerobic process can be assessed by monitoring the protozoa population in the system.

  5. Identifying proper agitation interval to prevent floating layers formation of corn stover and improve biogas production in anaerobic digestion.

    Science.gov (United States)

    Tian, Libin; Zou, Dexun; Yuan, Hairong; Wang, Linfeng; Zhang, Xin; Li, Xiujin

    2015-06-01

    Floating tests were conducted in anaerobic digestion with different OLR of corn stover to investigate formation of floating layers and to find proper agitation interval for preventing floating layer formation. Floating layers were formed in the early stage of no-agitation period. The daily biogas production was decreased by 81.87-87.90% in digesters with no agitation and feeding compared with digesters having agitation. Reduction of biogas production was mainly attributed to poor contact of substrate-microorganisms. Agitation intervals of 10 h, 6 h, and 2 h were found to be proper for eliminating floating layer at OLR of 1.44, 1.78 and 2.11 g(TS) L(-1) d(-1), respectively. The proper agitation interval was further validated by anaerobic experiments. It showed that proper agitation interval could not only prevent floating layer formation and achieve high biogas production but also increase energy efficiency of anaerobic digestion. The finding is useful for operating anaerobic digester with corn stover in a cost-effective way.

  6. Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine and Its Mononitroso Derivative Hexahydro-1-Nitroso-3,5-Dinitro-1,3,5-Triazine by Klebsiella pneumoniae Strain SCZ-1 Isolated from an Anaerobic Sludge

    OpenAIRE

    2002-01-01

    In previous work, we found that an anaerobic sludge efficiently degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), but the role of isolates in the degradation process was unknown. Recently, we isolated a facultatively anaerobic bacterium, identified as Klebsiella pneumoniae strain SCZ-1, using MIDI and the 16S rRNA method from this sludge and employed it to degrade RDX. Strain SCZ-1 degraded RDX to formaldehyde (HCHO), methanol (CH3OH) (12% of total C), carbon dioxide (CO2) (72% of total...

  7. 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.

  8. Free ammonia pre-treatment of secondary sludge significantly increases anaerobic methane production.

    Science.gov (United States)

    Wei, Wei; Zhou, Xu; Wang, Dongbo; Sun, Jing; Wang, Qilin

    2017-07-01

    Energy recovery in the form of methane from sludge/wastewater is restricted by the poor and slow biodegradability of secondary sludge. An innovative pre-treatment technology using free ammonia (FA, i.e. NH3) was proposed in this study to increase anaerobic methane production. The solubilisation of secondary sludge was significantly increased after FA pre-treatment at up to 680 mg NH3-N/L for 1 day, under which the solubilisation (i.e. 0.4 mg SCOD/mg VS; SCOD: soluble chemical oxygen demand; VS: volatile solids) was >10 times higher than that without FA pre-treatment (i.e. 0.03 mg SCOD/mg VS). Biochemical methane potential assays showed that FA pre-treatment at above 250 mg NH3-N/L is effective in improving anaerobic methane production. The highest improvement in biochemical methane potential (B0) and hydrolysis rate (k) was achieved at FA concentrations of 420-680 mg NH3-N/L, and was determined as approximately 22% (from 160 to 195 L CH4/kg VS added) and 140% (from 0.22 to 0.53 d(-1)) compared to the secondary sludge without pre-treatment. More analysis revealed that the FA induced improvement in B0 and k could be attributed to the rapidly biodegradable substances rather than the slowly biodegradable substances. Economic and environmental analyses showed that the FA-based technology is economically favourable and environmentally friendly. Since this FA technology aims to use the wastewater treatment plants (WWTPs) waste (i.e. anaerobic digestion liquor) to enhance methane production from the WWTPs, it will set an example for the paradigm shift of the WWTPs from 'linear economy' to 'circular economy'. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil

    Science.gov (United States)

    Won, Jongho; Borden, Robert C.

    2016-11-01

    Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate > 200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20 g/m3/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil.

  10. Wet air oxidation induced enhanced biodegradability of distillery effluent.

    Science.gov (United States)

    Malik, S N; Saratchandra, T; Tembhekar, P D; Padoley, K V; Mudliar, S L; Mudliar, S N

    2014-04-01

    The present study reports the feasibility of Wet Air Oxidation (WAO) as a pretreatment option for enhanced biodegradation of complex distillery effluent. Initially, the distillery effluent was pretreated by WAO at different process conditions (pressure, temperature and time) to facilitate enhancement in the biodegradability index (BI = BOD5: COD ratio). The biodegradability of WAO pretreated effluent was evaluated by subjecting it to aerobic biodegradation and anaerobic followed by aerobic biodegradation. Aerobic biodegradation of pretreated effluent with enhanced biodegradability index (BI = 0.4-0.8) showed enhanced COD reduction of up to 67.7%, whereas the untreated effluent (BI = 0.17) indicated poor COD reduction of only 22.5%. Anaerobic followed by aerobic biodegradation of pretreated effluent has shown up to 87.9% COD reduction, while the untreated effluent has shown only 43.1% COD reduction. Bio-kinetic parameters also confirmed the increased rate of bio-oxidation at enhanced BIs. The results indicate that the WAO pretreatment facilitates enhanced bio-oxidation/bio-degradation of complex effluents like the distillery spent wash.

  11. Biodegradation and bioremediation

    DEFF Research Database (Denmark)

    Albrechtsen, H.-J.

    1996-01-01

    Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994......Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994...

  12. High Intensity Interval Training Leads to Greater Improvements in Acute Heart Rate Recovery and Anaerobic Power as High Volume Low Intensity Training

    Directory of Open Access Journals (Sweden)

    Thomas L. Stöggl

    2017-08-01

    Full Text Available The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR in well-trained endurance athletes.Methods: Thirty-six male (n = 33 and female (n = 3 runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak: 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high intensity interval training HIIT; polarized training POL; high volume low intensity oriented control group CG/HVLIT applying no HIIT. A maximal anaerobic running/cycling test (MART/MACT was performed prior to and following a 9-week training period.Results: Only the HIIT group achieved improvements in peak power/velocity (+6.4%, P < 0.001 and peak lactate (P = 0.001 during the MART/MACT, while, unexpectedly, in none of the groups the performance at the established lactate concentrations (4, 6, 10 mmol·L−1 was changed (P > 0.05. Acute HRR was improved in HIIT (11.2%, P = 0.002 and POL (7.9%, P = 0.023 with no change in the HVLIT oriented control group.Conclusion: Only a training regime that includes a significant amount of HIIT improves the neuromuscular status, anaerobic power and the acute HRR in well-trained endurance athletes. A training regime that followed more a low and moderate intensity oriented model (CG/HVLIT had no effect on any performance or HRR outcomes.

  13. Biodegradable Nanoparticles of mPEG-PLGA-PLL Triblock Copolymers as Novel Non-Viral Vectors for Improving siRNA Delivery and Gene Silencing

    Directory of Open Access Journals (Sweden)

    Qiu-Sheng Shi

    2012-01-01

    Full Text Available Degradation of mRNA by RNA interference is one of the most powerful and specific mechanisms for gene silencing. However, insufficient cellular uptake and poor stability have limited its usefulness. Here, we report efficient delivery of siRNA via the use of biodegradable nanoparticles (NPs made from monomethoxypoly(ethylene glycol-poly(lactic-co-glycolic acid-poly-l-lysine (mPEG-PLGA-PLL triblock copolymers. Various physicochemical properties of mPEG-PLGA-PLL NPs, including morphology, size, surface charge, siRNA encapsulation efficiency, and in vitro release profile of siRNA from NPs, were characterized by scanning electron microscope, particle size and zeta potential analyzer, and high performance liquid chromatography. The levels of siRNA uptake and targeted gene inhibition were detected in human lung cancer SPC-A1-GFP cells stably expressing green fluorescent protein. Examination of the cultured SPC-A1-GFP cells with fluorescent microscope and flow cytometry showed NPs loading Cy3-labeled siRNA had much higher intracellular siRNA delivery efficiencies than siRNA alone and Lipofectamine-siRNA complexes. The gene silencing efficiency of mPEG-PLGA-PLL NPs was higher than that of commercially available transfecting agent Lipofectamine while showing no cytotoxicity. Thus, the current study demonstrates that biodegradable NPs of mPEG-PLGA-PLL triblock copolymers can be potentially applied as novel non-viral vectors for improving siRNA delivery and gene silencing.

  14. Biodegradable nanoparticles of mPEG-PLGA-PLL triblock copolymers as novel non-viral vectors for improving siRNA delivery and gene silencing.

    Science.gov (United States)

    Du, Jing; Sun, Ying; Shi, Qiu-Sheng; Liu, Pei-Feng; Zhu, Ming-Jie; Wang, Chun-Hui; Du, Lian-Fang; Duan, You-Rong

    2012-01-01

    Degradation of mRNA by RNA interference is one of the most powerful and specific mechanisms for gene silencing. However, insufficient cellular uptake and poor stability have limited its usefulness. Here, we report efficient delivery of siRNA via the use of biodegradable nanoparticles (NPs) made from monomethoxypoly(ethylene glycol)-poly(lactic-co-glycolic acid)-poly-l-lysine (mPEG-PLGA-PLL) triblock copolymers. Various physicochemical properties of mPEG-PLGA-PLL NPs, including morphology, size, surface charge, siRNA encapsulation efficiency, and in vitro release profile of siRNA from NPs, were characterized by scanning electron microscope, particle size and zeta potential analyzer, and high performance liquid chromatography. The levels of siRNA uptake and targeted gene inhibition were detected in human lung cancer SPC-A1-GFP cells stably expressing green fluorescent protein. Examination of the cultured SPC-A1-GFP cells with fluorescent microscope and flow cytometry showed NPs loading Cy3-labeled siRNA had much higher intracellular siRNA delivery efficiencies than siRNA alone and Lipofectamine-siRNA complexes. The gene silencing efficiency of mPEG-PLGA-PLL NPs was higher than that of commercially available transfecting agent Lipofectamine while showing no cytotoxicity. Thus, the current study demonstrates that biodegradable NPs of mPEG-PLGA-PLL triblock copolymers can be potentially applied as novel non-viral vectors for improving siRNA delivery and gene silencing.

  15. Lubricant Biodegradation Enhancers:Designed Chemistry and Engineered Technology

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Gao Lingyue; Fang Jianhua; Zhang Nan; Wu Jiang; Wang Jiu

    2015-01-01

    In recent decades, a growing worldwide trend of developing the biodegradable lubricants has been prevailing to form a speciifc ifeld of green chemistry and green engineering. Enhancement of biodegradability of unreadily biodegradable petroleum-based lubricants has as such become an urgent must. For over a decade the authors have been focusing on the im-provement of biodegradability of unreadily biodegradable lubricants such as petroleum-based lubricating oils and greases. A new idea of lubricant biodegradation enhancer was put forward by the authors with the aim to stimulate the biodegradation of unreadily biodegradable lubricants by incorporating the enhancer into the lubricants in order to turn the lubricants into greener biodegradable ones and to help in situ bioremediation of lubricant-contaminated environment. This manuscript sum-marizes our recent efforts relating to the chemistry and technology of biodegradation enhancers for lubricants. Firstly, the chemistry of lubricant biodegradation enhancers was designed based on the principles of bioremediation for the treatment of hydrocarbon contaminated environment. Secondly, the ability of the designed biodegradation enhancers for increasing the biodegradability of unreadily biodegradable industrial lubricants was investigated through biodegradability evaluation tests, microbial population analysis, and biodegradation kinetics modeling. Finally, the impact of biodegradation enhancers on some crucial performance characteristics of lubricants such as lubricity and oxidation stability was tested via tribological evaluation and oxidation determinations. Our results have shown that the designed chemistry of nitrogenous and/or phos-phorous compounds such as lauroyl glutamine, oleoyl glycine, oleic diethanolamide phosphate and lauric diethanolamide borate was outstanding in boosting biodegradation of petroleum-based lubricants which was ascribed to increase the micro-bial population and decrease the oil-water interfacial

  16. Biodegradation of UV-filters in marine sediments.

    Science.gov (United States)

    Volpe, Angela; Pagano, Michele; Mascolo, Giuseppe; Grenni, Paola; Rossetti, Simona

    2017-01-01

    The degradation of two of the most frequently used UV-filters was investigated through microcosm studies. Marine sediments sampled from two sites in Italy (La Spezia harbour and Sarno river estuary, S1 and S2 respectively) were used to set up aerobic and anaerobic sets of reactors. The sediments were spiked with a methanol solution of 3-(4-methylbenzylidene)camphor (4-MBC) and 2-ethylhexyl 4-(dimethylamino)benzoate (EH-DPAB), at concentrations of either 25 or 50mgkg(-1) each. Methanol (6.3g/L) also served as an organic amendment and growth substrate for improving microbial activity. Monitoring of the biotic and abiotic degradation of the selected contaminants over 16months revealed that 4-MBC biodegradation was very slow and incomplete, whereas over 90% of EH-DPAB was degraded both in the aerobic and the anaerobic reactors by the natural microbial communities of both sediments. Repeated spikes of EH-DPAB were followed by complete decay, characterised by first-order kinetics. The calculated kinetic rate constants under aerobic and anaerobic conditions were similar. In reactors inoculated with the S1 sediment the degradation rate constants progressively increased after each spike, up to the value of 0.039d(-1). For the S2 sediment the rate constant was around 0.020d(-1) throughout the duration of the experiment. Mass spectrometry analysis of sediment extracts allowed detection of potential transformation products of EH-DPAB and 4-MBC. Moreover, the natural microbial community of the sediments was studied using the CAtalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) both in the initial sediments and after degradation under aerobic and anaerobic conditions.

  17. Evaluation of the effects of nanoscale zero-valent iron (nZVI) dispersants on intrinsic biodegradation of trichloroethylene (TCE).

    Science.gov (United States)

    Chang, Y C; Huang, S C; Chen, K F

    2014-01-01

    In this study, the biodegradability of nanoscale zero-valent iron (nZVI) dispersants and their effects on the intrinsic biodegradation of trichloroethylene (TCE) were evaluated. Results of a microcosm study show that the biodegradability of three dispersants followed the sequence of: polyvinyl alcohol-co-vinyl acetate-co-itaconic acid (PV3A) > polyoxyethylene (20) sorbitan monolaurate (Tween 20) > polyacrylic acid (PAA) under aerobic conditions, and PV3A > Tween 20 > PAA under anaerobic conditions. Natural biodegradation of TCE was observed under both aerobic and anaerobic conditions. No significant effects were observed on the intrinsic biodegradation of TCE under aerobic conditions with the presence of the dispersants. The addition of PAA seemed to have a slightly adverse impact on anaerobic TCE biodegradation. Higher accumulation of the byproducts of anaerobic TCE biodegradation was detected with the addition of PV3A and Tween 20. The diversity of the microbial community was enhanced under aerobic conditions with the presence of more biodegradable PV3A and Tween 20. The results of this study indicate that it is necessary to select an appropriate dispersant for nZVI to prevent a residual of the dispersant in the subsurface. Additionally, the effects of the dispersant on TCE biodegradation and the accumulation of TCE biodegrading byproducts should also be considered.

  18. BIODEGRADATIVE ANALYSIS OF MUNICIPAL SOLID WASTE IN LABORATORY-SCALE LANDFILLS

    Science.gov (United States)

    The report gives results of research to characterize the anaerobic biodegradability of the major biodegradable components of municipal solid waste (MSW). Tests were conducted in quadruplicate in 2-L reactors operated to obtain maximum yields. Measured methane (CH4) yields for gra...

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

    Science.gov (United States)

    Zhang, Wanli; Zhang, Lei; Li, Aimin

    2015-11-01

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

  20. Partial degradation of levofloxacin for biodegradability improvement by electro-Fenton process using an activated carbon fiber felt cathode.

    Science.gov (United States)

    Gong, Yuexiang; Li, Jiuyi; Zhang, Yanyu; Zhang, Meng; Tian, Xiujun; Wang, Aimin

    2016-03-05

    Solutions of 500 mL 200 mg L(-1) fluoroquinolone antibiotic levofloxacin (LEVO) have been degraded by anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2) and electro-Fenton (EF) processes using an activated carbon fiber (ACF) felt cathode from the point view of not only LEVO disappearance and mineralization, but also biodegradability enhancement. The LEVO decay by EF process followed a pseudo-first-order reaction with an apparent rate constant of 2.37×10(-2)min(-1), which is much higher than that of AO or AO-H2O2 processes. The LEVO mineralization also evidences the order EF>AO-H2O2>AO. The biodegradability (BOD5/COD) increased from 0 initially to 0.24, 0.09, and 0.03 for EF, AO-H2O2 and AO processes after 360 min treatment, respectively. Effects of several parameters such as current density, initial pH and Fe(2+) concentration on the EF degradation have also been examined. Three carboxylic acids including oxalic, formic and acetic acid were detected, as well as the released inorganic ions NH4(+), NO3(-) and F(-). At last, an ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry was used to identify about eight aromatic intermediates formed in 60 min of EF treatment, and a plausible mineralization pathway for LEVO by EF treatment was proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Effects of Oxygen on Biodegradation of Fuels in a Corroding Environment

    Science.gov (United States)

    2013-06-12

    known to be more labile than hydrocarbons to anaerobic biodegradation (Aktas, et al, 2010), so the preferential loss of these peaks from the...the contention that hydrocarbon removal was due at least in part to biodegradation by seawater microorganisms. Benzoate, cresols and alkanoic acids...RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) · Oxygen Effects on Biodegradation of Fuels in a Corroding Environment Deniz F. Aktas

  2. Study on biodegradable aromatic/aliphatic copolyesters

    Energy Technology Data Exchange (ETDEWEB)

    Yiwang Chen; Licheng Tan; Lie Chen; Yan, Yang; Xiaofeng Wang [Nanchang University, Nanchang (China). School of Materials Science and Engineering. Inst. of Polymer Materials]. E-mail: ywchen@ncu.edu.cn

    2008-04-15

    Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The process ability of copolyesters could be improved significantly after incorporating a stiff chain segment through copolymerization of aliphatic polyesters with an aromatic liquid crystal element. The aromatic/aliphatic copolyesters as a new type of biodegradable materials could replace some general plastics in certain applications, namely biomedical and environmental friendly fields. (author)

  3. Study on biodegradable aromatic/aliphatic copolyesters

    Directory of Open Access Journals (Sweden)

    Yiwang Chen

    2008-06-01

    Full Text Available Progress on biodegradable aromatic/aliphatic copolyesters based on aliphatic and aromatic diacids, diols and ester monomers was reviewed. The aromatic/aliphatic copolyesters combined excellent mechanical properties with biodegradability. Physical properties and biodegradability of copolyesters varied with chain length of the aliphatic polyester segment and atacticity of copolyesters. The processability of copolyesters could be improved significantly after incorporating a stiff chain segment through copolymerization of aliphatic polyesters with an aromatic liquid crystal element. The aromatic/aliphatic copolyesters as a new type of biodegradable materials could replace some general plastics in certain applications, namely biomedical and environmental friendly fields.

  4. Biodegradable materials as foundry moulding sands binders

    Directory of Open Access Journals (Sweden)

    K. Major - Gabryś

    2015-07-01

    Full Text Available The aim of this article is to show the possibility of using biodegradable materials as part of the composition of foundry moulding and core sand binders. Research shows that moulding sands with biodegradable materials selected as binders are not only less toxic but are also better suited to mechanical reclamation than moulding sands with phenol-furfuryl resin. The use of biodegradable materials as additives to typical synthetic resins can result in their decreased toxicity and improved ability to reclamation as well as in accelerated biodegradation of binding material leftovers of mechanical reclamation.

  5. An improved enzyme-linked immunosorbent assay for whole-cell determination of methanogens in samples from anaerobic reactors

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Ahring, B.K.

    1997-01-01

    An enzyme-linked immunosorbent assay was developed for the detection of whole cells of methanogens in samples from anaerobic continuously stirred tank digesters treating slurries of solid waste. The assay was found to allow for quantitative analysis of the most important groups of methanogens......-quality microtiter plates and the addition of dilute hydrochloric acid to the samples. In an experiment on different digester samples, the test demonstrated a unique pattern of different methanogenic strains present in each sample. The limited preparatory work required for the assay and the simple assay design make...

  6. Lvad pump speed increase is associated with increased peak exercise cardiac output and vo2, postponed anaerobic threshold and improved ventilatory efficiency.

    Science.gov (United States)

    Vignati, Carlo; Apostolo, Anna; Cattadori, Gaia; Farina, Stefania; Del Torto, Alberico; Scuri, Silvia; Gerosa, Gino; Bottio, Tomaso; Tarzia, Vincenzo; Bejko, Jonida; Sisillo, Erminio; Nicoli, Flavia; Sciomer, Susanna; Alamanni, Francesco; Paolillo, Stefania; Agostoni, Piergiuseppe

    2017-03-01

    Peak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca-Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO. We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. Fifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation. All patients had severe HF as shown by clinical evaluation, laboratory tests, echocardiography, spirometry with alveolar-capillary diffusion, and maximal cardiopulmonary exercise testing (CPET). CPETs with non-invasive CO measurements at rest and peak exercise were done on 2days at LVAD pump speed set randomly at 2 and 4. Increasing LVAD pump speed from 2 to 4 increased CO from 3.4±0.9 to 3.8±1.0L/min (ΔCO 0.4±0.6L/min, p=0.04) and from 5.3±1.3 to 5.9±1.4L/min (ΔCO 0.6±0.7L/min, pincreased from 788±169 to 841±152mL/min (ΔVO2 52±76mL/min, p=0.01) and from 568±116 to 619±124mL/min (ΔVO2 69±96mL/min, p=0.02) at peak exercise and at anaerobic threshold, respectively. Δ(Ca-Cv)O2 did not change significantly, while ventilatory efficiency improved (VE/VCO2 slope from 39.9±5.4 to 34.9±8.3, ΔVE/VCO2 -5.0±6.4, pincrease in CO with a higher LVAD pump speed is associated with increased peak VO2, postponed anaerobic threshold, and improved ventilatory efficiency. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. 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...

  8. In situ detection of anaerobic alkane metabolites in subsurface environments

    OpenAIRE

    Lisa eGieg; Akhil eAgrawal

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic cond...

  9. In situ detection of anaerobic alkane metabolites in subsurface environments

    OpenAIRE

    Agrawal, Akhil; Gieg, Lisa M.

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditi...

  10. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher

    2001-07-31

    During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

  11. Conversion of Methanogenic Substrates in Anaerobic Reactors

    OpenAIRE

    Gonzalez-Gil, G.

    2000-01-01

    The EGSB systems represents an attractive option to extend further the use of anaerobic technology for wastewater treatment, particularly with respect to waste streams originating from chemical industries. Frequently chemical waste streams are unbalanced with respect to nutrients and/or micronutrients and furthermore these streams may contain toxic-biodegradable compounds. To reduce toxicity high recycle ratios may be applied as in the case of EGSB reactors however, this at the same time may ...

  12. Application of redox mediators to accelerate the transformation of reactive azo dyes in anaerobic bioreactors.

    NARCIS (Netherlands)

    Zee, van der F.P.; Bouwman, R.H.M.; Strik, D.P.B.T.B.; Lettinga, G.; Field, J.A.

    2001-01-01

    Azo dyes are nonspecifically reduced under anaerobic conditions but the slow rates at which reactive azo dyes are converted presents a serious problem for the application of anaerobic technology as a first stage in the complete biodegradation of these compounds. As quinones have been found to cataly

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

    NARCIS (Netherlands)

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

    2005-01-01

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

  14. Biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine and its mononitroso derivative hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine by Klebsiella pneumoniae strain SCZ-1 isolated from an anaerobic sludge.

    Science.gov (United States)

    Zhao, Jian-Shen; Halasz, Annamaria; Paquet, Louise; Beaulieu, Chantale; Hawari, Jalal

    2002-11-01

    In previous work, we found that an anaerobic sludge efficiently degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), but the role of isolates in the degradation process was unknown. Recently, we isolated a facultatively anaerobic bacterium, identified as Klebsiella pneumoniae strain SCZ-1, using MIDI and the 16S rRNA method from this sludge and employed it to degrade RDX. Strain SCZ-1 degraded RDX to formaldehyde (HCHO), methanol (CH3OH) (12% of total C), carbon dioxide (CO(2)) (72% of total C), and nitrous oxide (N2O) (60% of total N) through intermediary formation of methylenedinitramine (O(2)NNHCH(2)NHNO(2)). Likewise, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was degraded to HCHO, CH3OH, and N2O (16.5%) with a removal rate (0.39 micromol. h(-1). g [dry weight] of cells(-1)) similar to that of RDX (0.41 micromol. h(-1). g [dry weight] of cells(-1)) (biomass, 0.91 g [dry weight] of cells. liter(-1)). These findings suggested the possible involvement of a common initial reaction, possibly denitration, followed by ring cleavage and decomposition in water. The trace amounts of MNX detected during RDX degradation and the trace amounts of hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine detected during MNX degradation suggested that another minor degradation pathway was also present that reduced -NO2 groups to the corresponding -NO groups.

  15. Successful treatment of high azo dye concentration wastewater using combined anaerobic/aerobic granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR): simultaneous adsorption and biodegradation processes.

    Science.gov (United States)

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    The application of a granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR) for treatment of wastewater containing 1,000 mg/L Acid Red 18 (AR18) was investigated in this research. The treatment system consisted of a sequencing batch reactor equipped with moving GAC as biofilm support. Each treatment cycle consisted of two successive anaerobic (14 h) and aerobic (8 h) reaction phases. Removal of more than 91% chemical oxygen demand (COD) and 97% AR18 was achieved in this study. Investigation of dye decolorization kinetics showed that the dye removal was stimulated by the adsorption capacity of the GAC at the beginning of the anaerobic phase and then progressed following a first-order reaction. Based on COD analysis results, at least 77.8% of the dye total metabolites were mineralized during the applied treatment system. High-performance liquid chromatography analysis revealed that more than 97% of 1-naphthyalamine-4-sulfonate as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase. According to the scanning electron microscopic analysis, the microbial biofilms grew in most cavities and pores of the GAC, but not on the external surfaces of the GAC.

  16. 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.

  17. Methane production improvement by modulation of solid phase immersion in dry batch anaerobic digestion process: Dynamic of methanogen populations.

    Science.gov (United States)

    André, L; Ndiaye, M; Pernier, M; Lespinard, O; Pauss, A; Lamy, E; Ribeiro, T

    2016-05-01

    Several 60L dry batch anaerobic digestion (AD) reactors were implemented with or without liquid reserve on cattle manure. The immersed part modulation of cattle manure increased the methane flow of about 13%. The quantitative real time PCR and the optimized DNA extraction were implemented and validated to characterize and quantify the methanogen dynamic in dry batch AD process. Final quantities of methanogens converged toward the same level in several inocula at the end of AD. Methanogen dynamic was shown by dominance of Methanosarcinaceae for acetotrophic methanogens and Methanobacteriales for the hydrogenotrophic methanogens. Overall, methanogens populations were stabilized in liquid phase, except Methanosaetaceae. Solid phase was colonized by Methanomicrobiales and Methanosarcinaceae populations giving a support to biofilm development. The methane increase could be explained by a raise of Methanosarcinaceae population in presence of a total contact between solid and liquid phases. Methanosarcinaceae was a bio-indicator of the methane production.

  18. In situ detection of anaerobic alkane metabolites in subsurface environments

    Directory of Open Access Journals (Sweden)

    Lisa eGieg

    2013-06-01

    Full Text Available Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contibuting to modern-day detrimental effects such as oilfield souring, or may lead to more benefical technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments.

  19. In situ detection of anaerobic alkane metabolites in subsurface environments.

    Science.gov (United States)

    Agrawal, Akhil; Gieg, Lisa M

    2013-01-01

    Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contributing to modern-day detrimental effects such as oilfield souring, or may lead to more beneficial technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes) metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments.

  20. Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%-78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

  1. Degradation and biodegradability improvement of the olive mill wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes.

    Science.gov (United States)

    Esfandyari, Yahya; Mahdavi, Yousef; Seyedsalehi, Mahdi; Hoseini, Mohammad; Safari, Gholam Hossein; Ghozikali, Mohammad Ghanbari; Kamani, Hossein; Jaafari, Jalil

    2015-04-01

    Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD5), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO2/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m(2), 1000 mg/L H2O2, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96%, BOD5 by 93.6%, total, polyphenols by 94.4%, color by 91.4%, turbidity by 88.7, suspended solids by 97% and oil and grease by 97.1%. The biodegradability index (BOD5/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.

  2. Improving Polycyclic Aromatic Hydrocarbon Biodegradation in Contaminated Soil Through Low-Level Surfactant Addition After Conventional Bioremediation.

    Science.gov (United States)

    Adrion, Alden C; Singleton, David R; Nakamura, Jun; Shea, Damian; Aitken, Michael D

    2016-09-01

    Efficacy of bioremediation for soil contaminated with polycyclic aromatic hydrocarbons (PAHs) may be limited by the fractions of soil-bound PAHs that are less accessible to PAH-degrading microorganisms. In previous test-tube-scale work, submicellar doses of nonionic surfactants were screened for their ability to enhance the desorption and biodegradation of residual PAHs in soil after conventional bioremediation in a laboratory-scale, slurry-phase bioreactor. Polyoxyethylene sorbitol hexaoleate (POESH) was the optimum surfactant for enhancing PAH removal, especially the high-molecular weight PAHs. This work extends that concept by treating the effluent from the slurry-phase bioreactor in a second-stage batch reactor, to which POESH was added, for an additional 7 or 12 days. Surfactant amendment removed substantial amounts of the PAHs and oxy-PAHs remaining after conventional slurry-phase bioremediation, including more than 80% of residual 4-ring PAHs. Surfactant-amended treatment decreased soil cytotoxicity, but often increased the genotoxicity of the soil as measured using the DT-40 chicken lymphocyte DNA damage response assay. Potential ecotoxicity, measured using a seed germination assay, was reduced by bioreactor treatment and was reduced further after second-stage treatment with POESH. Of bacteria previously implicated as potential PAH degraders under POESH-amended conditions in a prior study, members of the Terrimonas genus were associated with differences in high-molecular weight PAH removal in the current study. Research using submicellar doses of surfactant as a second-stage treatment step is limited and these findings can inform the design of bioremediation systems at field sites treating soil contaminated with PAHs and other hydrophobic contaminants that have low bioaccessibility.

  3. Biodegradable thermogels.

    Science.gov (United States)

    Park, Min Hee; Joo, Min Kyung; Choi, Bo Gyu; Jeong, Byeongmoon

    2012-03-20

    All living creatures respond to external stimuli. Similarly, some polymers undergo conformational changes in response to changes in temperature, pH, magnetic field, electrical field, or the wavelength of light. In one type of stimuli-responsive polymer, thermogel polymers, the polymer aqueous solution undergoes sol-to-gel transition as the temperature increases. Drugs or cells can be mixed into the polymer aqueous solution when it is in its lower viscosity solution state. After injection of the solution into a target site, heating prompts the formation of a hydrogel depot in situ, which can then act as a drug releasing system or a cell growing matrix. In this Account, we describe key materials developed in our laboratory for the construction of biodegradable thermogels. We particularly emphasize recently developed polypeptide-based materials where the secondary structure and nanoassembly play an important role in the determining the material properties. This Account will provide insights for controlling parameters, such as the sol-gel transition temperature, gel modulus, critical gel concentration, and degradability of the polymer, when designing a new thermogel system for a specific biomedical application. By varying the stereochemistry of amino acids in polypeptides, the molecular weight of hydrophobic/hydrophilic blocks, the composition of the polypeptides, the hydrophobic end-capping of the polypeptides, and the microsequences of a block copolymer, we have controlled the thermosensitivity and nanoassembly patterns of the polymers. We have investigated a series of thermogel biodegradable polymers. Polymers such as poly(lactic acid-co-glycolic acid), polycaprolactone, poly(trimethylene carbonate), polycyanoacrylate, sebacic ester, polypeptide were used as hydrophobic blocks, and poly(ethylene glycol) and poly(vinyl pyrrolidone) were used as hydrophilic blocks. To prepare a polymer sensitive to pH and temperature, carboxylic acid or amine groups were introduced

  4. Biodegradability Improvement of Processes of Activated Carbon Catalyzed Ozonation for Coking Wastewater Treatment%活性炭催化臭氧氧化工艺对焦化废水可生化性的改善

    Institute of Scientific and Technical Information of China (English)

    常功法; 刘勃; 洪卫; 陈爱忠; 刘杰; 孙淑杰; 苏颖; 刘战修

    2015-01-01

    预氧化工艺常用来提高难降解工业废水的可生化性,其中以芬顿、臭氧应用最多。该文对这两种工艺提高煤化工行业焦化废水可生化性的性能做了对比,并提出了活性炭臭氧催化预氧化的改进工艺。试验表明单纯芬顿和臭氧预氧化并不能改善焦化废水的可生化性,而活性炭臭氧催化预氧化可以改善焦化废水的可生化性。经活性炭臭氧催化预氧化的焦化废水,BOD5/ COD从0.16增加到0.24,COD去除率从72.5%提高到83.0%。%Coking wastewater is hard to treat because of its low biodegradability,but pre-oxidation measurements such as Fenton and ozone can elevate its biodegradability. Two processes for improving biodegradability of coking wastewater were compared,and improvement methods of activated carbon catalyzed ozonation for coking wastewater treatment were got. The results show that neither Fenton oxidation nor ozonation can improve the biodegradability,but activated carbon catalyzed ozonation (AC-ozonation)can effectively improve biodegradability better. After AC-ozone,BOD 5 / COD increases from 0. 16 to 0. 25,and rate of COD increases from 72. 5% to 83% .

  5. 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.

  6. Influence of bioselector processes on 17α-ethinylestradiol biodegradation in activated sludge wastewater treatment systems.

    Science.gov (United States)

    Ziels, Ryan M; Lust, Mariko J; Gough, Heidi L; Strand, Stuart E; Stensel, H David

    2014-06-03

    The removal of the potent endocrine-disrupting estrogen hormone, 17α-ethinylestradiol (EE2), in municipal wastewater treatment plant (WWTP) activated sludge (AS) processes can occur through biodegradation by heterotrophic bacteria growing on other organic wastewater substrates. Different kinetic and metabolic substrate utilization conditions created with AS bioselector processes can affect the heterotrophic population composition in AS. The primary goal of this research was to determine if these changes also affect specific EE2 biodegradation kinetics. A series of experiments were conducted with parallel bench-scale AS reactors treating municipal wastewater with estrogens at 100-300 ng/L concentrations to evaluate the effect of bioselector designs on pseudo first-order EE2 biodegradation kinetics normalized to mixed liquor volatile suspended solids (VSS). Kinetic rate coefficient (kb) values for EE2 biodegradation ranged from 5.0 to 18.9 L/g VSS/d at temperatures of 18 °C to 24 °C. EE2 kb values for aerobic biomass growth at low initial food to mass ratio feeding conditions (F/Mf) were 1.4 to 2.2 times greater than that from growth at high initial F/Mf. Anoxic/aerobic and anaerobic/aerobic metabolic bioselector reactors achieving biological nutrient removal had similar EE2 kb values, which were lower than that in aerobic AS reactors with biomass growth at low initial F/Mf. These results provide evidence that population selection with growth at low organic substrate concentrations can lead to improved EE2 biodegradation kinetics in AS treatment.

  7. 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.

  8. 高盐条件下偶氮染料兼氧生物降解性能研究%Study on Facultative Anaerobic Biodegradation Performance of Azo Dyestuff under High Salt-containing Condition

    Institute of Scientific and Technical Information of China (English)

    仝攀瑞; 雷弢; 陈方方; 王晓艳; 常向东

    2012-01-01

    The facultative biodegradation performance of reactive dyestuffs is studied by using different concentrations glucose as co-substrate. Based on this, the facultative biodegradation performance of K-2BP under different salt-containing condition was investigated by static test reactor. The results indicated that facultative microorganisms had lower degradation rate when only K-2BP was used as the substrate, and the degradation rate would be increased under the existence of the glucose. The glucose concentration is 800 mg/L, while the degradation rate of K-2BP is 64. 1% at 6h. However, it is detrimental to dye' s biodegradation when the glucose concentration is up to 1000 mg/L, the degradation rate is only about 46% , that is similar to the condition without glucose. On the premise of glucose concentration 800 mg/L, when the salt concentrations are 2 g/‵ 5 g/L,10 g/L and 20 g/L respectively,the first-order kinetics constants are 0. 10578 mg/L · h,0.04947 mg/ L · h ,0.02869 mg/L · h and 0.022 75 mg/L · h respectively. And the half-lives were 6.99 h J4. 15 hN22. 55 h and 30.21h respectively. The reaction rate constants decrease gradually with the increase of the salt concentrations, and when the salt concentration is more than 2g/L, it can restrain the facultative microorganisms' degradation of K-2BP will be restrained.%研究活性染料与不同浓度葡萄糖在共基质条件下的兼氧生物降解性能,在此基础上,研究K-2BP在不同盐浓度条件下的兼氧生物降解性能.选择K-2BP作为目标污染物进行静态反应器生物降解试验,结果表明:兼氧微生物在只有K-2BP作为基质时对染料的降解率较低;葡萄糖存在时,能提高兼氧生物对染料的降解能力,葡萄糖为800 mg/L时,6h染料降解率为64.1%,而葡萄糖浓度为1 000 mg/L时,不利于染料降解,6h染料降解率为46%,与不投加葡萄糖情况的降解率接近.葡萄糖浓度为800mg/L,盐浓度分别为2,5,10和20 g/L,其一级

  9. Biodegradable polymeric prodrugs of naltrexone

    NARCIS (Netherlands)

    Bennet, D.B.; Li, X.; Adams, N.W.; Kim, S.W.; Hoes, C.J.T.; Feijen, J.

    1991-01-01

    The development of a biodegradable polymeric drug delivery system for the narcotic antagonist naltrexone may improve patient compliance in the treatment of opiate addiction. Random copolymers consisting of the ¿-amino acids N5-(3-hydroxypropyl--glutamine and -leucine were synthesized with equimolar

  10. Anaerobic thermophilic bacteria isolated from a Venezuelan oil field and its potential use in microbial improved oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Trebbau, G.; Fernandez, B.; Marin, A. [INTEVEP S.A., Caracas (Venezuela)

    1995-12-31

    The objective of this work is to determine the ability of indigenous bacteria from a Venezuelan oil field to grow under reservoir conditions inside a porous media, and to produce metabolites capable of recovering residual crude oil. For this purpose, samples of formation waters from a central-eastern Venezuelan oil reservoir were enriched with different carbon sources and a mineral basal media. Formation water was used as a source of trace metals. The enrichments obtained were incubated at reservoir temperature (71{degrees}C), reservoir pressure (1,200 psi), and under anaerobic conditions for both outside and inside porous media (Berea core). Growth and metabolic activity was followed outside porous media by measuring absorbance at 660 nm, increases in pressure, and decreases in pH. Inside porous media bacterial activity was determined by visual examination of the produced waters (gas bubbles and bacterial cells). All the carbohydrates tested outside porous media showed good growth at reservoir conditions. The pH was lowered, gases such as CO{sub 2} and CH{sub 4} were identified by GC. Surface tension was lowered in some enrichments by 30% when compared to controls. Growth was decreased inside porous media, but gases were produced and helped displace oil. In addition, 10% residual oil was recovered from the Berea core. Mathematical modeling was applied to the laboratory coreflood experiment to evaluate the reproducibility of the results obtained.

  11. Fed-batch cultivation of Desmodesmus sp. in anaerobic digestion wastewater for improved nutrient removal and biodiesel production.

    Science.gov (United States)

    Ji, Fang; Zhou, Yuguang; Pang, Aiping; Ning, Li; Rodgers, Kibet; Liu, Ying; Dong, Renjie

    2015-05-01

    Desmodesmus sp. was used in anaerobically digested wastewater (ADW) for nutrients removal and the biodiesel production was measured and compared using fed-batch cultivation was investigated and compared with batch cultivation. The Desmodesmus sp. was able to remove 236.143, 268.238 and 6.427 mg/L of TN, NH4-N and PO4-P respectively after 40 d of fed-batch cultivation, while in batch cultivation the quantities of TN, NH4-N and PO4-P removed were 33.331, 37.227 and 1.323 mg/L. Biomass production of Desmodesmus sp. was also enhanced in fed-batch cultivation, when ADW loading was carried out every 2 days; the biomass concentration peaked at 1.039 g/L, which was three times higher than that obtained in batch cultivation (0.385 g/L). The highest lipid production (261.8 mg/L) was also recorded in fed-batch cultivation as compared to batch cultivation (83.3 mg/L). Fed-batch cultivation of Desmodesmus sp. could provide effective control of nutrients limitation and/or ammonia inhibition on microalgae cultivation.

  12. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  13. Enhancing Biogas Production from Anaerobically Digested Wheat Straw Through Ammonia Pretreatment

    Institute of Scientific and Technical Information of China (English)

    杨懂艳; 庞云芝; 袁海荣; 陈树林; 马晶伟; 郁亮; 李秀金

    2014-01-01

    Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia (2%, 4%, and 6%, dry matter) and three moisture contents (30%, 60%, and 80%, dry matter) were applied to pretreat wheat straw for 7 days. The pretreated wheat straws were anaerobically digested at three loading rates (50, 65, and 80 g·L-1) to produce biogas. The results indi-cated that the wheat straw pretreated with 80%moisture content and 4%ammonia achieved the highest methane yield of 199.7 ml·g-1 (based on per unit volatile solids loaded), with shorter digestion time (T80) of 25 days at the loading rate of 65 g·L-1 compared to untreated one. The main chemical compositions of wheat straw were also ana-lyzed. The cellulose and hemicellulose contents were decomposed by 2%-20%and 26%-42%, respectively, while the lignin content was hardly removed, cold-water and hot-water extracts were increased by 4%-44%, and 12%-52%, respectively, for the ammonia-pretreated wheat straws at different moisture contents. The appropriate C/N ratio and decomposition of original chemical compositions into relatively readily biodegradable substances will improve the biodegradability and biogas yield.

  14. Biodegradable Sonobuoy Decelerators

    Science.gov (United States)

    2015-06-01

    Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment. Results showed that no PHA grades were toxic to the marine...accordance with ASTM D6691 “Standard Test Method for Determining Aerobic Biodegradation of Plastics Materials in the Marine Environment by a Defined...the biodegradation of a polymer vs. a stand- alone weight loss test. Biodegradation rates as high as these are rare for plastics in the marine

  15. Biodegradable synthetic bone composites

    Science.gov (United States)

    Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

    2013-01-01

    The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

  16. Biodegradation of aliphatic and aromatic polycarbonates.

    Science.gov (United States)

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.

  17. Effects of Different Co-substrates on the Biodegradation of Polycyclic Aromatic Hydrocarbons by Coking Sewage Sludge under Anaerobic Condition%厌氧条件下不同共基质对焦化污泥降解多环芳烃的影响

    Institute of Scientific and Technical Information of China (English)

    王鸣; 吴海珍; 刘雷; 韦朝海

    2016-01-01

    Coking wastewater contains various organic matter including polycyclic aromatic hydrocarbons (PAHs), phenolics, benzene and other substances. Phenol is the main component of COD in coking wastewater and the main carbon source for the microbial utilization in biological treatment process. In order to enhanced the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in coking wastewater treatment process, activated sludge was collected from an anaerobic tank of a coking wastewater treatment plant to studied the enhanced biodegradation and kinetics of benzo [a] pyrene (BaP) with phenol, glucose, sodium acetate, TritonX-100, and their combinations as cometabolic substrates, respectively. Moreover, the effects of the mentioned four substrates on the degradation processes of the mixtures of naphthalene, phenanthrene, anthracene, fluoranthene, pyrene and BaP were also investigated. The results showed that the addition of enhanced substrates promote the degradation of BaP and there were significant differences occurred in the degradation rates in the presence of different co-substrates. Sodium acetate demonstrated the highest enhancement of degradation for BaP while 39.9% of BaP can be degraded in 30 days. However, 27.1% of BaP were removed by phenol which was the slowest among the four different substrates; Compared to single substrate group, the combination of phenol and sodium acetate group had the best performance on the biodegradation of BaP and the degradation rate is 50.0%. In different systems, the biodegradation of BaP are followed the first order reaction kinetics model. In the presence of the six PAHs, sodium acetate still had the best enhancement effect, Within 20 days, the biodegradation rates of naphthalene, phenanthrene, anthracene, fluoranthene, pyrene and BaP are 66.1%, 60.7%, 43.2%, 22.0%, 15.5% and 14.7%, respectively. Coking sludge prefer to biodegrade low molecular weight PAHs, such as naphthalene, phenanthrene, anthracene. For high molecular

  18. Anaerobic treatability of wastewater contaminated with propylene glycol.

    Science.gov (United States)

    Sezgin, Naim; Tonuk, Gulseven Ubay

    2013-09-01

    The purpose of this study was to investigate the biodegradability of propylene glycol in anaerobic conditions by using methanogenic culture. A master reactor was set up to develop a culture that would be acclimated to propylene glycol. After reaching steady-state, culture was transferred to serum bottles. Three reactors with same initial conditions were run for consistency. Propylene glycol was completely biodegradable under anaerobic methanogenic conditions. Semi-continuous reactors operated at a temperature of 35°C had consistently achieved a propylene glycol removal of higher than 95 % based on chemical oxygen demand (COD). It was found that in semi-continuous reactors, anaerobic treatment of propylene glycol at concentrations higher than 1,500 mg COD m(-3) day(-1) was not convenient due to instable effluent COD.

  19. Anaerobic lactic acid degradation during ensilage of whole crop maize inoculated with lactobacillus buchneri inhibits yeast growth and improves aerobic stability

    Science.gov (United States)

    Driehuis; Elferink; Spoelstra

    1999-10-01

    Aerobic deterioration of silages is initiated by (facultative) aerobic micro-organisms, usually yeasts, that oxidize the preserving organic acids. In this study, a Lactobacillus buchneri strain isolated from maize silage was evaluated for its potential as a bacterial inoculant that enhances aerobic stability of silages. In four experiments, chopped whole crop maize (30-43% dry matter (DM)) was inoculated with Lact. buchneri and ensiled in laboratory silos. Uninoculated silages served as controls. Analysis of silages treated with Lact. buchneri at levels of 103-106 cfu g-1 after about 3 months of anaerobic storage showedthat acetic acid and 1-propanol contents increased with inoculum levels above 104 cfu g-1,whereas lactic acid decreased. Propionic acid, silage pH and DM loss increased withinoculum levels above 105 cfu g-1. Time course experiments with maize inoculated with Lact. buchneri at 4 x 104-2 x 105 cfu g-1 showed that up to 7-14 d after ensiling, Lact. buchneri had no effect on silage characteristics. Thereafter, the lactic acid content of the inoculated silages declined and, simultaneously, acetic acid and, to a lesser extent, propionic acid and 1-propanol, accumulated. Inoculation reduced survival of yeasts during the anaerobic storage phase and inhibited yeast growth when the silage was exposed to O2, resulting in a substantial improvement in aerobic stability. The results indicate that the use of Lact. buchneri as a silage inoculant can enhance aerobic stability by inhibition of yeasts. The ability of the organism to ferment lactic acid to acetic acid appears to be an important underlying principle of this effect.

  20. An improved titration model reducing over estimation of total volatile fatty acids in anaerobic digestion of energy crop, animal slurry and food waste.

    Science.gov (United States)

    Purser, B J Jobling; Thai, S-M; Fritz, T; Esteves, S R; Dinsdale, R M; Guwy, A J

    2014-09-15

    Titration methodologies have been used for the many years for low cost routine monitoring of full scale anaerobic digestion plants. These methodologies have been correlated to indicate the carbonate alkalinity and the volatile fatty acids (VFA) content within digesters. Two commonly used two end-point titration methods were compared using a dataset of 154 samples from energy crop and animal slurry digestates and were shown to be inaccurate in the estimation of tVFA. Using this dataset correlated with HPLC VFA analysis, two empirical bivariate linear regression equations were derived, where the validation dataset showed an absolute tVFA mean error improvement from ±3386 and ±3324 mg kg(-1) tVFA to ±410 and ±286 mg kg(-1) tVFA, respectively. The same equation was then applied to a food waste dataset where an absolute tVFA mean error was improved from ±3828 to ±576 mg kg(-1) tVFA. The newly derived titration equations can provide greater confidence in digester performance monitoring and are tools that can improve digester management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. [Biodegradation of polyethylene].

    Science.gov (United States)

    Yang, Jun; Song, Yi-ling; Qin, Xiao-yan

    2007-05-01

    Plastic material is one of the most serious solid wastes pollution. More than 40 million tons of plastics produced each year are discarded into environment. Plastics accumulated in the environment is highly resistant to biodegradation and not be able to take part in substance recycle. To increase the biodegradation efficiency of plastics by different means is the main research direction. This article reviewed the recent research works of polyethylene biodegradation that included the modification and pretreatment of polyethylene, biodegradation pathway, the relevant microbes and enzymes and the changes of physical, chemical and biological properties after biodegradation. The study directions of exploiting the kinds of life-forms of biodegradation polyethylene except the microorganisms, isolating and cloning the key enzymes and gene that could produce active groups, and enhancing the study on polyethylene biodegradation without additive were proposed.

  2. Aerobic and anaerobic microbial degradation of crude (4-methylcyclohexyl)methanol in river sediments.

    Science.gov (United States)

    Yuan, Li; Zhi, Wei; Liu, Yangsheng; Smiley, Elizabeth; Gallagher, Daniel; Chen, Xi; Dietrich, Andrea; Zhang, Husen

    2016-03-15

    Cyclohexane and some of its derivatives have been a major concern because of their significant adverse human health effects and widespread occurrence in the environment. The 2014 West Virginia chemical spill has raised public attention to (4-methylcyclohexyl)methanol (4-MCHM), one cyclohexane derivative, which is widely used in coal processing but largely ignored. In particular, the environmental fate of its primary components, cis- and trans-4-MCHM, remains largely unexplored. This study aimed to investigate the degradation kinetics and mineralization of cis- and trans-4-MCHM by sediment microorganisms under aerobic and anaerobic conditions. We found the removal of cis- and trans-4-MCHM was mainly attributed to biodegradation with little contribution from sorption. A nearly complete aerobic degradation of 4-MCHM occurred within 14 days, whereas the anaerobic degradation was reluctant with residual percentages of 62.6% of cis-4-MCHM and 85.0% of trans-4-MCHM after 16-day incubation. The cis-4-MCHM was degraded faster than the trans under both aerobic and anaerobic conditions, indicating an isomer-specific degradation could occur during the 4-MCHM degradation. Nitrate addition enhanced 4-MCHM mineralization by about 50% under both aerobic and anaerobic conditions. Both cis- and trans-4-MCHM fit well with the first-order kinetic model with respective degradation rates of 0.46-0.52 and 0.19-0.31 day(-)(1) under aerobic condition. Respective degradation rates of 0.041-0.095 and 0.013-0.052 day(-)(1) occurred under anaerobic condition. One bacterial strain capable of effectively degrading 4-MCHM isomers was isolated from river sediments and identified as Bacillus pumilus at the species level based on 16S rRNA gene sequence and 97% identity. Our findings will provide critical information for improving the prediction of the environmental fate of 4-MCHM and other cyclohexane derivatives with similar structure as well as enhancing the development of feasible treatment

  3. Evaluation of pre-treatment processes for increasing biodegradability of agro-food wastes.

    Science.gov (United States)

    Hidalgo, D; Sastre, E; Gómez, M; Nieto, P

    2012-01-01

    Anaerobic digestion (AD) technology can be employed for treating sewage sludge, livestock waste or food waste. Generally, the hydrolysis stage is the rate-limiting step of the AD processes for solid waste degradation. Therefore, physical, chemical and biological pre-treatment methods or their combination are required, in order to reduce the rate of such a limiting step. In this study, four methods (mechanical shredding, acid hydrolysis, alkaline hydrolysis and sonication) were tested to improve methane production and anaerobic biodegradability of different agro-food wastes and their mixtures. The kinetics of anaerobic degradation and methane production ofpre-treated individual wastes and selected mixtures were investigated with batch tests. Sonication at lower frequencies (37 kHz) proved to give the best results with methane productivity enhancements of over 100% in the case of pig manure and in the range of 10-47% for the other wastes assayed. Furthermore, the ultimate methane production was proportional, in all the cases, to the specific energy input applied (Es). Sonication can, thus, enhance waste digestion and the rate and quantity of biogas generated. The behaviour of the other pre-treatments under the conditions assayed is not significant. Only a slight enhancement of biogas production (around 10%) was detected for whey and waste activated sludge (WAS) after mechanical shredding. The lack of effectiveness of chemical pre-treatments (acid and alkaline hydrolysis) can be justified by the inhibition of the methanogenic process due to the presence of high concentrations of sodium (up to 8 g l(-1) in some tests). Only in the case of WAS did the acid hydrolysis considerably increase the biodegradability of the sample (79%), because in this case no inhibition by sodium took place. Some hints of a synergistic effect have been observed when co-digestion of the mixtures was performed.

  4. Biogas production improvement and C/N control by natural clinoptilolite addition into anaerobic co-digestion of Phragmites australis, feces and kitchen waste.

    Science.gov (United States)

    Wang, Xiaowei; Zhang, Lieyu; Xi, Beidou; Sun, Wenjun; Xia, Xunfeng; Zhu, Chaowei; He, Xiaosong; Li, Mingxiao; Yang, Tianxue; Wang, Pengfei; Zhang, Zhonglei

    2015-03-01

    Anaerobic co-digestion (A co-D) performance of Phragmites australis, feces and kitchen waste with addition of clinoptilolite (one main kind of zeolite) was investigated to evaluate the improvement of biogas/methane production and internal mechanism of nitrogen and organics control. A better biogas/methane production was observed by 10% clinoptilolite (v/v) than bentonite and diatomite, with the shortest lag phase of 0.070d(-1), the max rate of 15.89L/(kgVSday) and ultimate biogas production of 308.2L/kgVS as the modified Gompertz equation predicted. Accordingly, the content of methane in the biogas was increased from 44.10% to 65.30%. Furthermore, the clinoptilolite inhibited the acidification of digestion liquid (optimum pH 7.0-7.5) and enhanced the VFAs (acetic acid, propionic acid and butyric acid) destruction. Moreover, 10% of clinoptilolite optimally enhanced the microbial utilization of Ca(2+)/Mg(2+), controlled the C/N ratio, and improved the biogas production as well as NH3-N/NO3-N inhibition efficiency.

  5. 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....

  6. Tunable Biodegradable Nanocomposite Hydrogel for Improved Cisplatin Efficacy on HCT-116 Colorectal Cancer Cells and Decreased Toxicity in Rats.

    Science.gov (United States)

    Abdel-Bar, Hend Mohamed; Osman, Rihab; Abdel-Reheem, Amal Youssef; Mortada, Nahed; Awad, Gehanne A S

    2016-02-08

    This work describes the development of a modified nanocomposite thermosensitive hydrogel for controlled cisplatin release and improved cytotoxicity with decreased side effects. The system was characterized in terms of physical properties, morphological architecture and in vitro cisplatin release. Cytotoxicity was tested against human colorectal carcinoma HCT-116. In vivo studies were conducted to evaluate the acute toxicity in terms of rats' survival rate and body weight loss. Nephro and hepatotoxicities were evaluated followed by histopathological alterations of various tissue organs. Nanocomposite thermosensitive hydrogel containing nanosized carrier conferred density and stiffness allowing a zero order drug release for 14 days. Enhanced cytotoxicity with 2-fold decrease in cisplatin IC50 was accomplished. A linear in vivo-in vitro correlation was proved for the system degradation. Higher animal survival rate and lower tissue toxicities proved the decreased toxicity of cisplatin nanocomposite compared to its solution.

  7. Improvement of simultaneous Cr(VI) and phenol removal by an immobilised bacterial consortium and characterisation of biodegradation products.

    Science.gov (United States)

    Ontañon, Ornella M; González, Paola S; Barros, Germán G; Agostini, Elizabeth

    2017-07-25

    Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore polluted sites. Traditionally, the search for microorganisms suitable for bioremediation has been based on the selection of isolated strains able to remove a specific type of pollutant. However, this strategy has now become obsolete, since co-pollution is a global reality. Thus, current studies attempt to find bacterial cultures capable of coping with a mixture of organic and inorganic compounds. In this sense, the bacterial consortium SFC 500-1 has demonstrated efficiency for Cr(VI) and phenol removal, both of which are found in many industrial wastewaters. In the present study, the ability of SFC 500-1 for simultaneous removal was improved through its entrapment in a Ca-alginate matrix. This strategy led to an increased removal of Cr(VI), which was partially reduced to Cr(III). Immobilised cells were able to tolerate and degrade phenol up to 1,500mg/l at high rates, forming catechol and cis,cis-muconate as oxidation intermediates. Successful removal potential through 5 cycles of reuse, as well as after long-term storage, was another important advantage of the immobilised consortium. These characteristics make SFC 500-1 an interesting system for potential application in the biotreatment of co-polluted effluents. Copyright © 2017. Published by Elsevier B.V.

  8. Improving the physical and moisture barrier properties of Lepidium perfoliatum seed gum biodegradable film with stearic and palmitic acids.

    Science.gov (United States)

    Seyedi, Samira; Koocheki, Arash; Mohebbi, Mohebbat; Zahedi, Younes

    2015-01-01

    Stearic and palmitic fatty acids (10%, 20% and 30%, W/W gum) were used to improve the barrier properties of Lepidium perfoliatum seed gum (LPSG) film. The impact of the incorporation of fatty acids into the film matrix was studied by investigating the physical, mechanical, and barrier properties of the films. Addition of stearic and palmitic fatty acids to LPSG films reduced their water vapor permeability (WVP), moisture content, water solubility and water adsorption. Increasing fatty acid concentration from 10% to 30%, reduced the elongation at break (EB). Lower values of tensile strength (TS) and elastic modulus (EM) were obtained in the presence of higher fatty acids concentrations. Incorporation of fatty acids led to production of opaque films and the opacity increased as function of fatty acids concentration. Results showed that moisture content, water solubility and WVP decreased as the chain length of fatty acid increased. Therefore, LPSG-fatty acids composite film could be used for packaging in which a low affinity toward water is needed.

  9. Anaerobes in pleuropulmonary infections

    Directory of Open Access Journals (Sweden)

    De A

    2002-01-01

    Full Text Available A total of 76 anaerobes and 122 aerobes were isolated from 100 patients with pleuropulmonary infections, e.g. empyema (64, pleural effusion (19 and lung abscess (13. In 14% of the patients, only anaerobes were recovered, while a mixture of aerobes and anaerobes was encountered in 58%. From all cases of lung abscess, anaerobic bacteria were isolated, alone (04 or along with aerobic bacteria (13. From empyema and pleural effusion cases, 65.6% and 68.4% anaerobes were recovered respectively. Amongst anaerobes, gram negative anaerobic bacilli predominated (Prevotella melaninogenicus 16, Fusobacterium spp. 10, Bacteroides spp. 9, followed by gram positive anaerobic cocci (Peptostreptococcus spp. 31. Coliform bacteria (45 and Pseudomonas aeruginosa (42 were the predominant aerobic isolates.

  10. 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.

  11. Improving nutrient fixation and dry matter content of an ammonium-rich anaerobic digestion effluent by struvite formation and clay adsorption.

    Science.gov (United States)

    Estevez, Maria M; Linjordet, Roar; Horn, Svein J; Morken, John

    2014-01-01

    The anaerobic digestion (AD) of organic wastes that contain nitrogen leads to its mineralization, yielding a digestate rich in ammonium (NH(4)(+)), an important fertilizing nutrient. The applicability of AD digestate as fertilizer can be improved by fixating the nutrients and increasing its dry matter content. Methods for the fixation and recovery of the digestate's NH(4)(+) and possible also PO(4)(3-) include struvite precipitation and adsorption in clay materials such as bentonite. These techniques were tested in batch experiments employing the liquid fraction of a digestate originating from the AD of a substrate mix containing lignocellulose, cattle manure and fish industrial waste. The concentration of NH(4)(+)-N in this digestate was 2,300 mg L⁻¹. Struvite precipitation conditions at a molar ratio of 1.2:1:1 (Mg²⁺:NH(4)(+):PO(4)(3-)) and pH 9.5 were best in terms of simultaneous removal of NH(4)(+)-N (88%), PO(4)(3-) (60%) and soluble chemical oxygen demand (44%). Bentonite adsorption gave comparably high removal levels for NH(4)(+)-N (82%) and PO(4)(3-) (52%). Analysis of the precipitates' morphology and elemental composition confirmed their struvite and bentonite nature. Dry matter content was increased from 5.8% in the AD digestate to 27% and 22% in the struvite and bentonite sludges, respectively.

  12. Eliminating methanogenic activity in hydrogen reactor to improve biogas production in a two-stage anaerobic digestion process co-digesting municipal food waste and sewage sludge.

    Science.gov (United States)

    Zhu, Heguang; Parker, Wayne; Conidi, Daniela; Basnar, Robert; Seto, Peter

    2011-07-01

    Laboratory scale two-stage anaerobic digestion process model was operated for 280 days to investigate the feasibility to produce both hydrogen and methane from a mixture feedstock (1:1 (v/v)) of municipal food waste and sewage sludge. The maximum hydrogen and methane yields obtained in the two stages were 0.93 and 9.5 mL/mL feedstock. To eliminate methanogenic activity and obtain substantial hydrogen production in the hydrogen reactor, both feedstock and mixed liquor required treatment. The heat treatment (100°C, 10 min) for feedstock and a periodical treatment (every 2-5 weeks, either heating, removal of biomass particles or flushing with air) for mixed liquor were effective in different extent. The methane production in the second stage was significantly improved by the hydrogen production in the first stage. The maximum methane production obtained in the period of high hydrogen production was more than 2-fold of that observed in the low hydrogen production period.

  13. Sequential anaerobic-adsorption treatment of chemical industry wastewater.

    Science.gov (United States)

    Daga, Kailash; Pallavi, V; Patel, Dharmendra

    2011-10-01

    Treatment technologies needed to reduce the pollutant load of chemical industry effluent have been found to involve exorbitantly high costs. The present investigation aimed to treat the wastewater from chemical industry by cost effective sequential anaerobic-adsorption treatment. Wastewaters from chemical industry that are rich in biodegradable organics are tested for anaerobic treatability. The efficiency of anaerobic reactor is relatively lower 79.3%, and therefore post treatment of effluent was done by adsorption using Poly vinyl alcohol coated Datura stramonium (PVAC-DS) as an adsorbent. An overall COD removal of 93.8 % was achieved after sequential Anaerobic-Adsorption treatment, which lead to a better final effluent and a more economical treatment system.

  14. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

    CHAO WANG; GUAN-GHUA LU; YAN-JIE ZHOU

    2007-01-01

    Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes,Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

  15. Corn stover for biogas production: Effect of steam explosion pretreatment on the gas yields and on the biodegradation kinetics of the primary structural compounds.

    Science.gov (United States)

    Lizasoain, Javier; Trulea, Adrian; Gittinger, Johannes; Kral, Iris; Piringer, Gerhard; Schedl, Andreas; Nilsen, Paal J; Potthast, Antje; Gronauer, Andreas; Bauer, Alexander

    2017-08-12

    This study evaluated the effect of steam explosion on the chemical composition and biomethane potential of corn stover using temperatures ranging between 140 and 220°C and pretreatment times ranging between 2 and 15min. Biodegradation kinetics during the anaerobic digestion of untreated and corn stover, pretreated at two different intensities, 140°C for 5min and 180°C for 5min, were studied in tandem. Results showed that pretreatment at 160°C for 2min improved the methane yield by 22%. Harsher pretreatment conditions led to lower hemicellulose contents and methane yields, as well as higher lignin contents, which may be due to the formation of pseudo-lignin. The biodegradation kinetics trial demonstrated that steam explosion enhances the degradation of structural carbohydrates and acid insoluble lignin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  17. Polymer material biodegradation

    Directory of Open Access Journals (Sweden)

    B. Grabowska

    2010-04-01

    Full Text Available Data from literature was used to discuss the impact of external factors (stress, radiation, temperature, ultrasounds, biological organisms on the course of polymer material degradation. Polymer materials, in widespread use for over a dozen years, constitute a serious environmental problem. This is why their susceptibility to biodegradation is researched. Work on biodegradable polymers concernsmodifying their structure to bring their physical and chemical properties closer to plastics in practical use or using biodegradable polymers as an alternative for the current conventional materials. In addition, the publication also presents the first results of work on the biodegradation of polymer foundry binders.

  18. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  19. Oestradiol-releasing Biodegradable Mesh Stimulates Collagen Production and Angiogenesis: An Approach to Improving Biomaterial Integration in Pelvic Floor Repair.

    Science.gov (United States)

    Mangır, Naşide; Hillary, Christopher J; Chapple, Christopher R; MacNeil, Sheila

    2017-06-03

    Polypropylene meshes cause severe complications in some patients. Materials that are biomechanically compatible and can better integrate into host tissues are urgently needed. To design an oestradiol-releasing electrospun poly-l-lactic acid (PLA) mesh and evaluate its ability to stimulate new extracellular matrix and new blood vessel formation. Human adipose derived mesenchymal cells (ADMSC) were isolated from fat. PLA meshes with micro- to nano-sized fibres containing 1%, 5%, and 10% oestradiol were constructed and used for in vitro and in vivo experiments. The angiogenic potential of the fibrous meshes was evaluated using an in vivo chorioallantoic membrane and an in vitro chick aortic arch assays. Oestradiol release was measured fluorometrically. The effect of fibrous meshes on proliferation and extracellular matrix (ECM) production of ADMSC was assessed using immunohistology. Mechanical properties were tested using a tensiometer. The ultrastructure of the mesh was not affected by the inclusion of oestradiol and mechanical properties were only slightly modified. Oestradiol was released from PLA meshes over a 5-mo period. ADMSCs cultured on oestradiol-releasing PLA meshes produced more ECM involving collagen I, collagen III, and elastin. Oestradiol-releasing meshes doubled new blood vessel formation in the chorioallantoic membrane assay (p=0.001) and outgrowth of pro-angiogenic cells in the aortic arch assay (p=0.001). Further studies in longer-term animal models are required to confirm these results. Oestradiol-releasing PLA meshes increase ECM production and stimulate angiogenesis. As such, they are promising candidate materials to be used in pelvic floor repair and to improve the initial healing phase of a repair material following implantation. In this study, we designed a tissue engineered material to be used to support weakened pelvic floor tissues in women to avoid the complications associated with current surgical mesh. Our results showed that this

  20. Determination of main components and anaerobic rumen digestibility of aquatic plants in vitro using near-infrared-reflectance spectroscopy.

    Science.gov (United States)

    Yue, Zheng-Bo; Zhang, Meng-Lin; Sheng, Guo-Ping; Liu, Rong-Hua; Long, Ying; Xiang, Bing-Ren; Wang, Jin; Yu, Han-Qing

    2010-04-01

    A near-infrared-reflectance (NIR) spectroscopy-based method is established to determine the main components of aquatic plants as well as their anaerobic rumen biodegradability. The developed method is more rapid and accurate compared to the conventional chemical analysis and biodegradability tests. Moisture, volatile solid, Klason lignin and ash in entire aquatic plants could be accurately predicted using this method with coefficient of determination (r(2)) values of 0.952, 0.916, 0.939 and 0.950, respectively. In addition, the anaerobic rumen biodegradability of aquatic plants, represented as biogas and methane yields, could also be predicted well. The algorithm of continuous wavelet transform for the NIR spectral data pretreatment is able to greatly enhance the robustness and predictive ability of the NIR spectral analysis. These results indicate that NIR spectroscopy could be used to predict the main components of aquatic plants and their anaerobic biodegradability.

  1. Assessment of anaerobic bacterial diversity and its effects on anaerobic system stability and the occurrence of antibiotic resistance genes.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-05-01

    This study evaluated the link between anaerobic bacterial diversity and, the biodegradation of antibiotic combinations and assessed how amending antibiotic combination and increasing concentration of antibiotics in a stepwise fashion influences the development of resistance genes in anaerobic reactors. The biodegradation, sorption and occurrence of the known antibiotic resistance genes (ARGs) of erythromycin and tetracycline were investigated using the processes of UV-HPLC and qPCR analysis respectively. Ion Torrent sequencing was used to detect microbial community changes in response to the addition of antibiotics. The overall results indicated that changes in the structure of a microbial community lead to changes in biodegradation capacity, sorption of antibiotics combinations and occurrence of ARGs. The enhanced biodegradation efficiency appeared to generate variations in the structure of the bacterial community. The results suggested that controlling the ultimate Gram-negative bacterial community, especially Acinetobacter-related populations, may promote the successful biodegradation of antibiotic combinations and reduce the occurrence of ARGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. The effect of operational conditions on the sludge specific methanogenic activity and sludge biodegradability

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, R. C.; Santaella, S. T.; Haandel, A. C. van; Zeeman, G.; Lettinga, G.

    2009-07-01

    The Specific Methanogenic Activity (SMA) and sludge biodegradability of an anaerobic sludge depends on various operational and environmental conditions imposed to the anaerobic reactor. However, the effects of hydraulic retention time (HRT), influent COD concentration (COD{sub i}nf) and sludge retention time (SRT) on those two parameters need to be elucidated. This knowledge about SMA can provide insights about the capacity of the UASB reactors to withstand organic and hydraulic shock loads, whereas the biodegradability gives information necessary for final disposal of the sludge. (Author)

  3. 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...

  4. Biodegradable fiksasyon malzemeleri

    OpenAIRE

    Seber, Sinan

    2004-01-01

    Problems related to metallic implant had increased the interest to biodegradables. In this paper, the physical and chemical properties, degradation modalities, implant design, clinical studies with techniques, and complications of biodegradable implants, especially polylactic and polyglycolic acid, were reviewed. Also our studies, on the antibiotic delivery capacities of these implants; and the prediction of immunological reactions with our clinical experiences were presented.

  5. Biodegradation of plastics.

    Science.gov (United States)

    Shimao, M

    2001-06-01

    Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes.

  6. Engineering Flame Retardant Biodegradable Nanocomposites

    Science.gov (United States)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  7. Fabrication of Biodegradable Polyester Nanocomposites by Electrospinning for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Zhi-Cai Xing

    2011-01-01

    Full Text Available Recently, nanocomposites have emerged as an efficient strategy to upgrade the structural and functional properties of synthetic polymers. Polyesters have attracted wide attention because of their biodegradability and biocompatibility. A logic consequence has been the introduction of natural extracellular matrix (ECM molecules, organic or inorganic nanostructures to biodegradable polymers to produce nanocomposites with enhanced properties. Consequently, the improvement of the interfacial adhesion between biodegradable polymers and natural ECM molecules or nanostructures has become the key technique in the fabrication of nanocomposites. Electrospinning has been employed extensively in the design and development of tissue engineering scaffolds to generate nanofibrous substrates of synthetic biodegradable polymers and to simulate the cellular microenvironment. In this paper, several types of biodegradable polyester nanocomposites were prepared by electrospinning, with the aim of being used as tissue engineering scaffolds. The combination of biodegradable nanofibrous polymers and natural ECM molecules or nanostructures opens new paradigms for tissue engineering applications.

  8. 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.

  9. 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...

  10. 镁基生物可降解材料耐蚀性能改善研究进展∗%The Research Progress of Improving Corrosion Resistance of Magnesium Based Biodegradable Materials

    Institute of Scientific and Technical Information of China (English)

    韩知为; 张秉君; 翁杰

    2016-01-01

    Since twenty-first century,magnesium is playing an increasingly important role in the field of biode-gradable implants. Magnesium has good biodegradability and its mechanical properties are similar to those of natural bone,showing a good development prospect. However,the degradation of magnesium would be too fast among the physiological environments in the body and would make against the functional expression of implant because of the local alkalization and local gas cavity after degradation. This paper reviews the progress in application of biodegrad-able magnesium alloy in the field of biomedical material for orthopedics,discusses the research aiming at the im-provement of degradable magnesium alloy’s corrosion resistance and the existing problems for clinical application at home and abroad. It is clear that the biodegradable magnesium alloy is a promising bone substitute materials after some problems related to its degradation is solved.%21世纪以来,新型可降解生物镁合金因其良好的可降解性能,与自体骨相似的机械性能而被研究者广泛关注,显示出良好的发展前景。然而其在体液环境下过快降解,造成局部碱化和局部气腔等现象均不利于其作为植入物的功能性表达和患处的正常愈合。文章综述了可降解镁合金在生物医学骨科材料领域的应用研究进展,重点分析讨论了国内外可降解镁合金耐蚀性能改善的情况及现存的推向临床的问题,提出了生物可降解镁合金应用于临床所亟待解决的问题,并展望了未来的发展趋势。

  11. Thermophillic treatment by anaerobic granular sludge as an effective approach to accelerate the electron transfer and improve the reductive decolorization of azo dyes in bioreactors

    NARCIS (Netherlands)

    Santos, dos A.B.; Traverse, J.; Cervantes, F.J.; Lier, van J.B.

    2005-01-01

    The effects of temperature, hydraulic retention time (HRT), and the redox mediator, thraquinone- 2,6-disulfonate (AQDS), on electron transfer and subsequent reductive decolorization of dyes rom textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly

  12. UV-C mutagenesis of Kluyveromyces marxianus NRRL Y-1109 strain for improved anaerobic growth at elevated temperature on pentose and hexose sugars

    Science.gov (United States)

    More robust industrial yeast strains from Kluyveromyces marxianus NRRL Y-1109 and have been produced using UV-C irradiation specifically for anaerobic conversion of lignocellulosic sugar streams to fuel ethanol at elevated temperature (45°C). This type of random mutagenesis offers the possibility o...

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

    Science.gov (United States)

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

    2016-01-15

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

  14. Wheat straw pretreatment with KOH for enhancing biomethane production and fertilizer value in anaerobic digestion☆

    Institute of Scientific and Technical Information of China (English)

    Muhammad Jaffar; Yunzhi Pang; Hairong Yuan; Dexun Zou; Yanping Liu; Baoning Zhu; Rashid Mustafa Korai; Xiujin Li

    2016-01-01

    Wheat straw biodegradability during anaerobic digestion was improved by treatment with potassium hydroxide (KOH) to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations of 1%(K1), 3%(K2), 6%(K3) and 9%(K4) were tested for wheat straw pretreatment at ambient temperature with a C:N ratio of 25:1. 86%of total solids (TS), 89%of volatile solids (VS) and 22%of lignocel ulose, cellulose and hemi-cellulose (LCH) (22%) were decomposed effectively with the wheat straw pretreated by 6%KOH. Enhanced bio-gas production and cumulative biomethane yield of 258 ml·(g VS)−1 were obtained increased by 45%and 41%respectively, compared with untreated wheat straw. Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium (138%), calcium (22%) and magnesium (16%). These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value.

  15. 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.

  16. 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.

  17. 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.

  18. [Accelerating effects of immobilized anthanquinone on the anaerobic biodegradation].

    Science.gov (United States)

    Guo, Jian-bo; Zhou, Ji-ti; Wang, Dong; Tian, Cun-ping; Wang, Ping; Wang, Jing; Salah, Uddin; Li, Li-hua

    2006-10-01

    The accelerating effect of anthanquinone as a redox mediator in the bio-decolorization was conducted. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under immobilized anthanquinone and high salt conditions. Anthnaquinone used as a redox mediator was able to increase the decolorization rate of wastewater containing azo dyes, and was immobilized by entrapment in calcium alginate (CA), polyvinyl alcohol (PVA)-H3BO3, polyvinyl alcohol (PVA)-calcium alginate (CA) and agar, respectively. The effects of various operating conditions such as anthnaquinone bead number and dissolved oxygen on microbial decolorization were investigated experimentally. At the same time, immobilized anthanquinone was tested to assess the effects on the change of the oxidation-reduction potential (ORP) values during the decolorization processes. High decolorization rate was obtained in the presence of 200 anthnaquinone immobilization beads at 30 degrees C, which increased 1.5-2 fold, in comparison with the control of free-anthanquinone. The oxidation-reduction potential (ORP) values stabilized around -260 to approximately -265 mV after 6 hours anoxic conditions, which lowered ORP values around -10 to approximately -15 mV by anthanquinone. The reusability of the anthnaquinone immobilization beads was evaluated with repeated-bacth decolorization experiments. After four repeated experiments, the decolorization rate of calcium alginate (CA) immobilized anthnaquinone retained over 90% of their original activity.

  19. Integrated sequential anaerobic/aerobic biodegradation of azo dyes

    NARCIS (Netherlands)

    Tan, N.C.G.

    2001-01-01

    Azo dyes constitute a major class of environmental pollutants accounting for 60 to 70% of all dyes and pigments used. These compounds are characterized by aromatic moieties linked together with azo groups (-N=N-). The release of azo dyes into the environment is a concern due to coloration of natural

  20. Integrated and sequential anaerobic/aerobic biodegradation of azo dyes

    NARCIS (Netherlands)

    Tan, N.G.C.

    2001-01-01

    Azo dyes constitute a major class of environmental pollutants accounting for 60 to 70% of all dyes and pigments used. These compounds are characterized by aromatic moieties linked together with azo groups (-N=N-). The release of azo dyes into the environment is a concern due to coloration o

  1. Biodegradability of Plastics

    OpenAIRE

    Yutaka Tokiwa; Calabia, Buenaventurada P.; Charles U. Ugwu; Seiichi Aiba

    2009-01-01

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical ...

  2. Polymer material biodegradation

    OpenAIRE

    B. Grabowska

    2010-01-01

    Data from literature was used to discuss the impact of external factors (stress, radiation, temperature, ultrasounds, biological organisms) on the course of polymer material degradation. Polymer materials, in widespread use for over a dozen years, constitute a serious environmental problem. This is why their susceptibility to biodegradation is researched. Work on biodegradable polymers concernsmodifying their structure to bring their physical and chemical properties closer to plastics in prac...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-15

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

  4. Microbial ecology of methanogenic crude oil biodegradation; from microbial consortia to heavy oil

    Energy Technology Data Exchange (ETDEWEB)

    Head, Ian M.; Maguire, Michael J.; Sherry, Angela; Grant, Russell; Gray, Neil D.; Aitken, Carolyn M.; Martin Jones, D.; Oldenburg, Thomas B.P.; Larter, Stephen R. [Petroleum Research Group, Geosciences, University of Calgary (Canada)

    2011-07-01

    This paper presents the microbial ecology of methanogenic crude oil biodegradation. Biodegraded petroleum reservoirs are one of the most dramatic indications of the deep biosphere. It is estimated that heavy oil and oil sands will account for a considerable amount of energy production in the future. Carbon, a major resource for deep subsurface microorganisms, and energy are contained in large quantities in petroleum reservoirs. The aerobic to anaerobic paradigm shift is explained. A key process for in-situ oil biodegradation in petroleum reservoirs is methanogenesis. New paradigms for in-reservoir crude oil biodegradation are discussed. Variations in anaerobic degradation of crude oil hydrocarbons are also discussed. A graph shows the different patterns of crude oil biodegradation under sulfate-reducing and methanogenic conditions. Alternative anaerobic alkane activation mechanisms are also shown. From the study, it can be concluded that methanogenic crude oil degradation is of global importance and led to the establishment of the world's enormous heavy oil deposits.

  5. Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil.

    Science.gov (United States)

    Won, Jongho; Borden, Robert C

    2016-11-01

    Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate >200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20g/m(3)/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. 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.

  7. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    Science.gov (United States)

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  8. 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...

  9. Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

    Science.gov (United States)

    Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

    2016-02-15

    To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material.

  10. PLLA scaffolds surface-engineered via poly (propylene imine) dendrimers for improvement on its biocompatibility/controlled pH biodegradability

    Science.gov (United States)

    Ganjalinia, Atiyeah.; Akbari, Somaye.; Solouk, Atefeh.

    2017-02-01

    Novel aminolyzed Poly (L) Lactic Acid (PLLA) films and electrospun nanofibrous scaffolds were fabricated and characterized as potential substrates for tissue engineering. The second generation polypropylene imine dendrimer (PPI-G2) was used as the aminolysis agent to functionalize the inert surface of PLLA substrates directly without any pre-modification process. The effect of the solvent type, G2 concentration, reaction temperature and time were studied by following weight reduction percentage, FTIR and contact angle measurements due to determined optimum conditions. In addition, the modified scaffolds abbreviated by PLLA/G2 were analyzed using mechanical properties, SEM images and dye assays as host-guest modeling. The results indicate that under the 0.5 (wt.%) G2 concentration, ethanol as the solvent, room temperature and 4 h of treatment, the optimum conditions were obtained. It was shown that the hydrophilic properties of PLLA/G2 were greatly enhanced. Also, pH value analysis revealed that after 4 weeks, the biodegradation of PLLA caused massive immune cells infusion and inflammation in the medium through increasing the acidic rate by secretion the lactic acid, whereas the PLLA/G2 scaffolds greatly reduced and stabilize the acidic rate through aminolysis reaction. Finally, promoted cell adhesion and viability underlined the favorable properties of PLLA/G2 scaffolds as a biodegradable biomaterial for biomedical implants.

  11. AEROBIC AND ANAEROBIC TREATMENT OF C.I. DISPERSE BLUE 79 - VOLUME II, APPENDICES

    Science.gov (United States)

    This study was conducted to determine the fate of C.I. Disperse Blue 79, one of the largest production volume dyes, and select biodegradation products in a conventionally operated activated sludge process and an anaerobic sludge digestion system. To achieve this objective, a pilo...

  12. AEROBIC AND ANAEROBIC TREATMENT OF C.I. DISPERSE BLUE 79 - VOLUME I

    Science.gov (United States)

    This study was conducted to determine the fate of C.I. Disperse Blue 79, one of the largest production volume dyes, and select biodegradation products in a conventionally operated activated sludge process and an anaerobic sludge digestion system. To achieve this objective, a pilo...

  13. The role of natural wood constituents on the anaerobic treatability of forest industry wastewaters

    NARCIS (Netherlands)

    Sierra-Alvarez, R.

    1990-01-01

    Anaerobic treatment has been shown to be an efficient and energy conserving method for treating various types of readily biodegradable non-inhibitory forest industry wastewaters. However, the high toxicity of paper mill effluents derived from chemical wood processing operations has hampered the wide

  14. The role of natural wood constituents on the anaerobic treatability of forest industry wastewaters

    NARCIS (Netherlands)

    Sierra - Alvarez, R.

    1990-01-01

    Anaerobic treatment has been shown to be an efficient and energy conserving method for treating various types of readily biodegradable non-inhibitory forest industry wastewaters. However, the high toxicity of paper mill effluents derived from chemical wood processing operations has hampered

  15. ADM1-based modeling of anaerobic digestion of swine manure fibers pretreated with aqueous ammonia soaking

    DEFF Research Database (Denmark)

    Jurado, Esperanza; Gavala, Hariklia N.; Skiadas, Ioannis

    2012-01-01

    Anaerobic digestion of manure fibers present challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) and subsequent ammonia removal has been tested as a simple and cheap method to disrupt the lignocellulose and increase the methane potential and the biogas productivity of manure...

  16. Evidence for PAH Removal Coupled to the First Steps of Anaerobic Digestion in Sewage Sludge

    Directory of Open Access Journals (Sweden)

    Glenda Cea-Barcia

    2013-01-01

    Full Text Available Anaerobic degradation of polycyclic aromatic hydrocarbons has been brought to the fore, but information on removal kinetics and anaerobic degrading bacteria is still lacking. In order to explore the organic micropollutants removal kinetics under anaerobic conditions in regard to the methane production kinetics, the removal rate of 12 polycyclic aromatic hydrocarbons was measured in two anaerobic batch reactors series fed with a highly loaded secondary sludge as growth substrate. The results underscore that organic micropollutants removal is coupled to the initial stages of anaerobic digestion (acidogenesis and acetogenesis. In addition, the organic micropollutants kinetics suggest that the main removal mechanisms of these hydrophobic compounds are biodegradation and/or sequestration depending on the compounds.

  17. Biogas and biohydrogen production potential of high strength automobile industry wastewater during anaerobic degradation.

    Science.gov (United States)

    Bajaj, Mini; Winter, Josef

    2013-10-15

    High strength automobile industry wastewater, collected from decanters (DECA) of the pre-treatment plant after oil, grease and sludge separation, was investigated for production of methane in the absence and presence of glucose or excess aerobic sludge (AS) from a lab scale suspension reactor as co-substrates. The highest methane production from DECA wastewater was 335.4 L CH4/kg CODsoluble removal which decreased in the presence of the co-substrates to 232.5 (with 2 g/L glucose) and to 179 (with 40% AS) L CH4/kg CODsoluble removal, respectively. Around 95% of total methane was produced within 5 days of incubation of DECA at 37 °C when no co-substrate was added. Addition of co-substrates did not improve biodegradation of DECA but overall methane production from DECA + co-substrates was increased due to co-substrate biodegradation. The anaerobic inoculum, capable of producing 2.4 mol of hydrogen/mol of glucose under zinc induced inhibitory conditions, was unable to produce hydrogen from DECA as substrate under the same conditions.

  18. Sequential biodegradation of complex naphtha hydrocarbons under methanogenic conditions in two different oil sands tailings.

    Science.gov (United States)

    Mohamad Shahimin, Mohd Faidz; Siddique, Tariq

    2017-02-01

    Methane emissions in oil sands tailings ponds are sustained by anaerobic biodegradation of unrecovered hydrocarbons. Naphtha (primarily C6-C10; n- iso- and cycloalkanes) is commonly used as a solvent during bitumen extraction process and its residue escapes to tailings ponds during tailings deposition. To investigate biodegradability of hydrocarbons in naphtha, mature fine tailings (MFT) collected from Albian and CNRL tailings ponds were amended with CNRL naphtha at ∼0.2 wt% (∼2000 mg L(-1)) and incubated under methanogenic conditions for ∼1600 d. Microbial communities in both MFTs started metabolizing naphtha after a lag phase of ∼100 d. Complete biodegradation/biotransformation of all n-alkanes (except partial biodegradation of n-octane in CNRL MFT) followed by major iso-alkanes (2-methylpentane, 3-methylhexane, 2- and 4-methylheptane, iso-nonanes and 2-methylnonane) and a few cycloalkanes (derivatives of cyclopentane and cyclohexane) was observed during the incubation. 16S rRNA gene pyrosequencing showed dominance of Peptococcaceae and Anaerolineaceae in Albian MFT and Anaerolineaceae and Syntrophaceae in CNRL MFT bacterial communities with co-domination of Methanosaetaceae and "Candidatus Methanoregula" in archaeal populations during active biodegradation of hydrocarbons. The findings extend the known range of hydrocarbons susceptible to methanogenic biodegradation in petroleum-impacted anaerobic environments and help refine existing kinetic model to predict greenhouse gas emissions from tailings ponds. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Biodegradable nanoparticles for gene therapy technology

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinkhani, Hossein, E-mail: hosseinkhani@mail.ntust.edu.tw; He, Wen-Jie [National Taiwan University of Science and Technology (Taiwan Tech), Graduate Institute of Biomedical Engineering (China); Chiang, Chiao-Hsi [School of Pharmacy, National Defense Medical Center (China); Hong, Po-Da [National Taiwan University of Science and Technology (Taiwan Tech), Graduate Institute of Biomedical Engineering (China); Yu, Dah-Shyong [Nanomedicine Research Center, National Defense Medical Center (China); Domb, Abraham J. [The Hebrew University of Jerusalem, Institute of Drug Research, School of Pharmacy, Faculty of Medicine, Center for Nanoscience and Nanotechnology and The Alex Grass Center for Drug Design and Synthesis (Israel); Ou, Keng-Liang [College of Oral Medicine, Taipei Medical University, Research Center for Biomedical Devices and Prototyping Production (China)

    2013-07-15

    Rapid propagations in materials technology together with biology have initiated great hopes in the possibility of treating many diseases by gene therapy technology. Viral and non-viral gene carriers are currently applied for gene delivery. Non-viral technology is safe and effective for the delivery of genetic materials to cells and tissues. Non-viral systems are based on plasmid expression containing a gene encoding a therapeutic protein and synthetic biodegradable nanoparticles as a safe carrier of gene. Biodegradable nanoparticles have shown great interest in drug and gene delivery systems as they are easy to be synthesized and have no side effect in cells and tissues. This review provides a critical view of applications of biodegradable nanoparticles on gene therapy technology to enhance the localization of in vitro and in vivo and improve the function of administered genes.

  20. Molecularly Imprinted Biodegradable Nanoparticles

    Science.gov (United States)

    Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

    2017-01-01

    Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization.

  1. Molecularly Imprinted Biodegradable Nanoparticles

    Science.gov (United States)

    Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

    2017-01-01

    Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization. PMID:28071745

  2. An Esterase from Anaerobic Clostridium hathewayi Can Hydrolyze Aliphatic-Aromatic Polyesters.

    Science.gov (United States)

    Perz, Veronika; Hromic, Altijana; Baumschlager, Armin; Steinkellner, Georg; Pavkov-Keller, Tea; Gruber, Karl; Bleymaier, Klaus; Zitzenbacher, Sabine; Zankel, Armin; Mayrhofer, Claudia; Sinkel, Carsten; Kueper, Ulf; Schlegel, Katharina; Ribitsch, Doris; Guebitz, Georg M

    2016-03-15

    Recently, a variety of biodegradable polymers have been developed as alternatives to recalcitrant materials. Although many studies on polyester biodegradability have focused on aerobic environments, there is much less known on biodegradation of polyesters in natural and artificial anaerobic habitats. Consequently, the potential of anaerobic biogas sludge to hydrolyze the synthetic compostable polyester PBAT (poly(butylene adipate-co-butylene terephthalate) was evaluated in this study. On the basis of reverse-phase high-performance liquid chromatography (RP-HPLC) analysis, accumulation of terephthalic acid (Ta) was observed in all anaerobic batches within the first 14 days. Thereafter, a decline of Ta was observed, which occurred presumably due to consumption by the microbial population. The esterase Chath_Est1 from the anaerobic risk 1 strain Clostridium hathewayi DSM-13479 was found to hydrolyze PBAT. Detailed characterization of this esterase including elucidation of the crystal structure was performed. The crystal structure indicates that Chath_Est1 belongs to the α/β-hydrolases family. This study gives a clear hint that also micro-organisms in anaerobic habitats can degrade manmade PBAT.

  3. Promoting anaerobic biogasification of corn stover through biological pretreatment by liquid fraction of digestate (LFD).

    Science.gov (United States)

    Hu, Yun; Pang, Yunzhi; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Chufo, Wachemo Akiber; Jaffar, Muhammad; Li, Xiujin

    2015-01-01

    A new biological pretreatment method by using liquid fraction of digestate (LFD) was advanced for promoting anaerobic biogasification efficiency of corn stover. 17.6% TS content and ambient temperature was appropriate for pretreatment. The results showed that C/N ratio decreased to about 30, while total lignin, cellulose, and hemicellulose (LCH) contents were reduced by 8.1-19.4% after pretreatment. 3-days pretreatment was considered to be optimal, resulting in 70.4% more biogas production, 66.3% more biomethane yield and 41.7% shorter technical digestion time compared with the untreated stover. The reductions on VS, cellulose, and hemicellulose were increased by 22.1-35.9%, 22.3-35.4%, and 19.8-27.2% for LFD-treated stovers. The promoted anaerobic biogasification efficiency was mainly attributed to the improved biodegradability due to the pre-decomposition role of the bacteria in LFD. The method proved to be an efficient and low cost approach for producing bioenergy from corn stover, meanwhile, reducing LFD discharge and minimizing its potential pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Comparison of anaerobic digestion characteristics and kinetics of four livestock manures with different substrate concentrations.

    Science.gov (United States)

    Li, Kun; Liu, Ronghou; Sun, Chen

    2015-12-01

    Anaerobic digestions of pig manure (PM), dairy manure (DM), chicken manure (CM) and rabbit manure (RM) at initial volatile solid loading (VSL) of 8 g VS/L, 16 g VS/L, 32 g VS/L, 64 g VS/L were investigated under mesophilic conditions. The maximum methane yields of 410, 270, 377 and 323 mL CH4/g VSadded for PM, DM, CM and RM were all obtained at initial VSL of 8 g VS/L, respectively. The improvement of substrate concentration to 64 g VS/L not only decreased the methane yield and biodegradability both by 22.4%, 37.3%, 49.1% and 34.6% for PM, DM, CM and RM respectively, but also reduced the methane content in final biogas production. The Cone model (R(2): 0.9910-0.9974) showed a better fit to the experiment data and the calculated parameters indicated that anaerobic digestion of manures at higher loading has longer lag phase and lower hydrolysis rate.

  6. 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...

  7. 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...

  8. Fertilization stimulates anaerobic fuel degradation of antarctic soils by denitrifying microorganisms.

    Science.gov (United States)

    Powell, Shane M; Ferguson, Susan H; Snape, Ian; Siciliano, Steven D

    2006-03-15

    Human activities in the Antarctic have resulted in hydrocarbon contamination of these fragile polar soils. Bioremediation is one of the options for remediation of these sites. However, little is known about anaerobic hydrocarbon degradation in polar soils and the influence of bioremediation practices on these processes. Using a field trial at Old Casey Station, Antarctica, we assessed the influence of fertilization on the anaerobic degradation of a 20-year old fuel spill. Fertilization increased hydrocarbon degradation in both anaerobic and aerobic soils when compared to controls, but was of most benefit for anaerobic soils where evaporation was negligible. This increased biodegradation in the anaerobic soils corresponded with a shift in the denitrifier community composition and an increased abundance of denitrifiers and benzoyl-CoA reductase. A microcosm study using toluene and hexadecane confirmed the degradative capacity within these soils under anaerobic conditions. It was observed that fertilized anaerobic soil degraded more of this hydrocarbon spike when incubated anaerobically than when incubated aerobically. We conclude that denitrifiers are actively involved in hydrocarbon degradation in Antarctic soils and that fertilization is an effective means of stimulating their activity. Further, when communities stimulated to degrade hydrocarbons under anaerobic conditions are exposed to oxygen, hydrocarbon degradation is suppressed. The commonly accepted belief that remediation of polar soils requires aeration needs to be reevaluated in light of this new data.

  9. Green and biodegradable electronics

    Directory of Open Access Journals (Sweden)

    Mihai Irimia-Vladu

    2012-07-01

    Full Text Available We live in a world where the lifetime of electronics is becoming shorter, now approaching an average of several months. This poses a growing ecological problem. This brief review will present some of the initial steps taken to address the issue of electronic waste with biodegradable organic electronic materials. Many organic materials have been shown to be biodegradable, safe, and nontoxic, including compounds of natural origin. Additionally, the unique features of such organic materials suggest they will be useful in biofunctional electronics; demonstrating functions that would be inaccessible for traditional inorganic compounds. Such materials may lead to fully biodegradable and even biocompatible/biometabolizable electronics for many low-cost applications. This review highlights recent progress in these classes of material, covering substrates and insulators, semiconductors, and finally conductors.

  10. Two-phase anaerobic digestion of vegetable market waste fraction of municipal solid waste and development of improved technology for phase separation in two-phase reactor.

    Science.gov (United States)

    Majhi, Bijoy Kumar; Jash, Tushar

    2016-12-01

    Biogas production from vegetable market waste (VMW) fraction of municipal solid waste (MSW) by two-phase anaerobic digestion system should be preferred over the single-stage reactors. This is because VMW undergoes rapid acidification leading to accumulation of volatile fatty acids and consequent low pH resulting in frequent failure of digesters. The weakest part in the two-phase anaerobic reactors was the techniques applied for solid-liquid phase separation of digestate in the first reactor where solubilization, hydrolysis and acidogenesis of solid organic waste occur. In this study, a two-phase reactor which consisted of a solid-phase reactor and a methane reactor was designed, built and operated with VMW fraction of Indian MSW. A robust type filter, which is unique in its implementation method, was developed and incorporated in the solid-phase reactor to separate the process liquid produced in the first reactor. Experiments were carried out to assess the long term performance of the two-phase reactor with respect to biogas production, volatile solids reduction, pH and number of occurrence of clogging in the filtering system or choking in the process liquid transfer line. The system performed well and was operated successfully without the occurrence of clogging or any other disruptions throughout. Biogas production of 0.86-0.889m(3)kg(-1)VS, at OLR of 1.11-1.585kgm(-3)d(-1), were obtained from vegetable market waste, which were higher than the results reported for similar substrates digested in two-phase reactors. The VS reduction was 82-86%. The two-phase anaerobic digestion system was demonstrated to be stable and suitable for the treatment of VMW fraction of MSW for energy generation.

  11. A strategy for aromatic hydrocarbon bioremediation under anaerobic conditions and the impacts of ethanol: A microcosm study

    Science.gov (United States)

    Chen, Yu Dao; Barker, James F.; Gui, Lai

    2008-02-01

    Increased use of ethanol-blended gasoline (gasohol) and its potential release into the subsurface have spurred interest in studying the biodegradation of and interactions between ethanol and gasoline components such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) in groundwater plumes. The preferred substrate status and the high biological oxygen demand (BOD) posed by ethanol and its biodegradation products suggests that anaerobic electron acceptors (EAs) will be required to support in situ bioremediation of BTEX. To develop a strategy for aromatic hydrocarbon bioremediation and to understand the impacts of ethanol on BTEX biodegradation under strictly anaerobic conditions, a microcosm experiment was conducted using pristine aquifer sand and groundwater obtained from Canadian Forces Base Borden, Canada. The initial electron accepter pool included nitrate, sulfate and/or ferric iron. The microcosms typically contained 400 g of sediment, 600˜800 ml of groundwater, and with differing EAs added, and were run under anaerobic conditions. Ethanol was added to some at concentrations of 500 and 5000 mg/L. Trends for biodegradation of aromatic hydrocarbons for the Borden aquifer material were first developed in the absence of ethanol, The results showed that indigenous microorganisms could degrade all aromatic hydrocarbons (BTEX and trimethylbenzene isomers-TMB) under nitrate- and ferric iron-combined conditions, but not under sulfate-reducing conditions. Toluene, ethylbenzene and m/p-xylene were biodegraded under denitrifying conditions. However, the persistence of benzene indicated that enhancing denitrification alone was insufficient. Both benzene and o-xylene biodegraded significantly under iron-reducing conditions, but only after denitrification had removed other aromatics. For the trimethylbenzene isomers, 1,3,5-TMB biodegradation was found under denitrifying and then iron-reducing conditions. Biodegradation of 1,2,3-TMB or 1,2,4-TMB was slower under iron

  12. 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...

  13. 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.

  14. 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)

  15. Effect of basic operating parameters on biological phosphorus removal in a continuous-flow anaerobic-anoxic activated sludge system.

    Science.gov (United States)

    Kapagiannidis, A G; Zafiriadis, I; Aivasidis, A

    2012-03-01

    A continuous-flow anaerobic-anoxic (A2) activated sludge system was operated for efficient enhanced biological phosphorus removal (EBPR). Because of the system configuration with no aeration zones, phosphorus (P) uptake takes place solely under anoxic conditions with simultaneous denitrification. Basic operating conditions, namely biomass concentration, influent carbon to phosphorus ratio and anaerobic retention time were chosen as variables in order to assess their impact on the system performance. The experimental results indicated that maintenance of biomass concentration above 2,500 mg MLVSS/L resulted in the complete phosphate removal from the influent (i.e. 15 mg PO(4) (3-)-P/L) for a mean hydraulic residence time (HRT) of 15 h. Additionally, by increasing the influent COD/P ratio from 10 to 20 g/g, the system P removal efficiency was improved although the experimental results indicated a possible enhancement of the competition between phosphorus accumulating organisms (PAOs) and other microbial populations without phosphorus uptake ability. Moreover, because of the use of acetate (i.e. easily biodegradable substrate) as the sole carbon source in the system feed, application of anaerobic retention times greater than 2 h resulted in no significant release of additional P in the anaerobic zone and no further amelioration of the system P removal efficiency. The application of anoxic P removal resulted in more than 50% reduction of the organic carbon necessitated for nitrogen and phosphorus removal when compared to a conventional EBPR system incorporating aerobic phosphorus removal.

  16. Effect of different ratios of cow manure and corn straw on the mixed anaerobic fermentation rate

    Directory of Open Access Journals (Sweden)

    Zongshan JIANG

    2016-08-01

    Full Text Available In order to study the effect of the different ratios on the anaerobic fermentation rate is investigated, and the rate-limiting factors are preliminarily determined, at mesophilic (38±1℃ condition, with anaerobic granular sludge as inoculums, different ratios of cow manure and corn straw are used as substrate for mixed anaerobic fermentation. By measuring daily biogas production, the concentrations of CH4 and CO2 in the marsh gas, TC, the concentration of VFAs and pH value, The results show that under the mixture ratio of 2∶1, the hydrolysis rate constants, cumulative biogas yield and biodegradability CH4 reach their high limits, which are 0.043 7 d-1, 271.93 mL/g and 71.59%, respectively. Moreover, it is found that the concentration of acetic acid is proportional to the amount of cow manure at the beginning (the first day of mixed fermentation, and the concentration of propionicacid is proportional to the amount of corn straw in medium fermentation stage (the fifth day. In addition, rate-limiting step of biogas production is related to the ratio of cow manure and corn in fermentation material. With the increasing of corn straw proportion, on the 1st day, it tends to hydrolysis acidogenesis; from the 2th day to 15th day, it tends to hydrogen-production acetogenisis; and from the 16th day to 30th day, it is hydrolysis acidogenesis. The paper focuses on the relationship between the ratio of cow manure and corn straw and the rate-limiting step for biogas production, which could provide a theoretical and experimental support for improving the efficiency of biogas production in mixed fermentation.

  17. Biodegradation of disinfection byproducts as a potential removal process during aquifer storage recovery

    Science.gov (United States)

    Landmeyer, J.E.; Bradley, P.M.; Thomas, J.M.

    2000-01-01

    The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of tri-halomethanes in drinking water.The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water.Aquifer-storage-recovery injection water often contains disinfection byproducts. Results are presented from a study in which two model disinfection

  18. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Lier, van J.B.

    2011-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different condi

  19. Biodegradable Materials for Nonwovens

    Science.gov (United States)

    Demand for nonwovens is increasing globally, particularly in the disposable products area. As the consumption of nonwoven products with short life increases, the burden on waste disposal also rises. In this context, biodegradable nonwovens become more important today and for the future. Several new ...

  20. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Van Lier, J.B.

    2010-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different condi

  1. Microbial degradation of 4-monobrominated diphenyl ether with anaerobic sludge

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Yang-hsin, E-mail: yhs@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China); Chou, Hsi-Ling [Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 407, Taiwan, ROC (China); Peng, Yu-Huei [Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan, ROC (China)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer BDE-3 was degraded with two anaerobes in different rates. Black-Right-Pointing-Pointer Glucose addition augment the debromination efficiencies. Black-Right-Pointing-Pointer Hydrogen gas was detected and relative microbes were identified. Black-Right-Pointing-Pointer Extra-carbon source enhanced degradation partial due to H{sub 2}-generation bacteria. - Abstract: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant additives for many plastic and electronic products. Owing to their ubiquitous distribution in the environment, multiple toxicity to humans, and increasing accumulation in the environment, the fate of PBDEs is of serious concern for public safety. In this study, the degradation of 4-monobrominated diphenyl ether (BDE-3) in anaerobic sludge and the effect of carbon source addition were investigated. BDE-3 can be degraded by two different anaerobic sludge samples. The by-products, diphenyl ether (DE) and bromide ions, were monitored, indicating the reaction of debromination within these anaerobic samples. Co-metabolism with glucose facilitated BDE-3 biodegradation in terms of kinetics and efficiency in the Jhongsing sludge. Through the pattern of amplified 16S rRNA gene fragments in denatured gradient gel electrophoresis (DGGE), the composition of the microbial community was analyzed. Most of the predominant microbes were novel species. The fragments enriched in BDE-3-degrading anaerobic sludge samples are presumably Clostridium sp. This enrichment coincides with the H{sub 2} gas generation and the facilitation of debromination during the degradation process. Findings of this study provide better understanding of the biodegradation of brominated DEs and can facilitate the prediction of the fate of PBDEs in the environment.

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

    Science.gov (United States)

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

    2012-10-01

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

  3. [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.

  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. Pretreatment of microalgae to improve biogas production: a review.

    Science.gov (United States)

    Passos, Fabiana; Uggetti, Enrica; Carrère, Hélène; Ferrer, Ivet

    2014-11-01

    Microalgae have been intensively studied as a source of biomass for replacing conventional fossil fuels in the last decade. The optimization of biomass production, harvesting and downstream processing is necessary for enabling its full-scale application. Regarding biofuels, biogas production is limited by the characteristics of microalgae, in particular the complex cell wall structure of most algae species. Therefore, pretreatment methods have been investigated for microalgae cell wall disruption and biomass solubilization before undergoing anaerobic digestion. This paper summarises the state of the art of different pretreatment techniques used for improving microalgae anaerobic biodegradability. Pretreatments were divided into 4 categories: (i) thermal; (ii) mechanical; (iii) chemical and (iv) biological methods. According to experimental results, all of them are effective at increasing biomass solubilization and methane yield, pretreatment effect being species dependent. Pilot-scale research is still missing and would help evaluating the feasibility of full-scale implementation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Biodegradation of olive-mill pomace mixed with organic fraction of municipal solid waste.

    Science.gov (United States)

    Ağdağ, Osman Nuri

    2011-09-01

    This study investigated the effects of organic fraction of municipal solid waste (OFMSW) addition on the anaerobic treatment of the olive-mill pomace. Biodegradability of olive-mill pomace mixed with OFMSW was examined in anaerobic bioreactors. Only OFMSW was loaded in the first (control) bioreactor, while run 1 and run 2 bioreactors included different ratio of OFMSW and olive-mill pomace. COD, BOD(5), NH(4)-N, pH, VFA, CH(4) quantity and percentage in anaerobic bioreactors were regularly monitored. In addition, inert COD and anaerobic toxicity assay (ATA) were measured in leachate samples. The results of the study showed that 70% of OFMSW addition to olive-mill pomace has an advantage in terms of pollution parameters and methane generation. Since olive-mill pomace is not easy biodegradable, addition of high proportion of OFMSW promotes biodegradability of olive-mill pomace. Decreasing in BOD(5)/COD ratios in the run 1 and run 2 reactors carried out as 62 and 52%, respectively.

  7. Biodegradability and ecotoxicity of commercially available geothermal heat transfer fluids

    Science.gov (United States)

    Schmidt, Kathrin R.; Körner, Birgit; Sacher, Frank; Conrad, Rachel; Hollert, Henner; Tiehm, Andreas

    2016-03-01

    Commercially available heat transfer fluids used in borehole heat exchangers were investigated for their composition, their biodegradability as well as their ecotoxicity. The main components of the fluids are organic compounds (often glycols) for freezing protection. Biodegradation of the fluids in laboratory studies caused high oxygen depletion as well as nitrate/iron(III) reduction under anaerobic conditions. Additives such as benzotriazoles for corrosion protection were persistent. Ecotoxicity data show that the commercially available fluids caused much higher ecotoxicity than their main organic constituents. Consequently, with regard to groundwater protection pure water as heat transfer medium is recommended. The second best choice is the usage of glycols without any additives. Effects on groundwater quality should be considered during ecological-economical cost-benefit-analyses of further geothermal energy strategies. The protection of groundwater as the most important drinking water resource must take priority over the energy gain from aquifers.

  8. Biodegradability of leachates from Chinese and German municipal solid waste

    Institute of Scientific and Technical Information of China (English)

    SELIC E.; WANG Chi; BOES N., HERBELL J.D.

    2007-01-01

    The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.

  9. Applying Raman spectroscopy to the assessment of the biodegradation of industrial polyurethanes wastes.

    Science.gov (United States)

    Cregut, Mickael; Bedas, Marion; Assaf, Ali; Durand-Thouand, Marie-José; Thouand, Gérald

    2014-01-01

    Polyether-based polyurethanes (PBP) are extremely problematic polymers due to their long persistence in the environment. Moreover, the assessment of PBP biodegradation remains biased due to the inability of conventional methods to determine how their diverse subunits are degraded. To improve our knowledge of PBP biodegradation, we used Raman spectroscopy to identify patterns of PBP biodegradation. Specifically, PBP biodegradation was assessed using a microbial inoculum isolated from an industrial soil in which polyurethanes have been buried for 40 years. During a 28-day biodegradation assay, the PBP biodegradation level reached 27.5% (w/w), in addition to undergoing profound alteration of the PBP composition as identified by chemical analyses. After microbial degradation, Raman analyses revealed the disappearance of the polymer's amorphous region, which contains a high polyol content, whereas the isocyanate-rich crystalline regions were preserved. The use of Raman spectroscopy appears to be a particularly useful tool to enhance our assessment of polymer biodegradation.

  10. Comparative study on the biodegradation and biocompatibility of silicate bioceramic coatings on biodegradable magnesium alloy as biodegradable biomaterial

    Science.gov (United States)

    Razavi, M.; Fathi, M. H.; Savabi, O.; Razavi, S. M.; Hashemibeni, B.; Yazdimamaghani, M.; Vashaee, D.; Tayebi, L.

    2014-03-01

    Many clinical cases as well as in vivo and in vitro assessments have demonstrated that magnesium alloys possess good biocompatibility. Unfortunately, magnesium and its alloys degrade too quickly in physiological media. In order to improve the biodegradation resistance and biocompatibility of a biodegradable magnesium alloy, we have prepared three types of coating include diopside (CaMgSi2O6), akermanite (Ca2MgSi2O6) and bredigite (Ca7MgSi4O16) coating on AZ91 magnesium alloy through a micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method. In this research, the biodegradation and biocompatibility behavior of samples were evaluated in vitro and in vivo. The in vitro analysis was performed by cytocompatibility and MTT-assay and the in vivo test was conducted on the implantation of samples in the greater trochanter of adult rabbits. The results showed that diopside coating has the best bone regeneration and bredigite has the best biodegradation resistance compared to others.

  11. Biodegradability potential of two experimental landfills in Brazil

    Directory of Open Access Journals (Sweden)

    Vazoller Rosana Filomena

    2001-01-01

    Full Text Available Solid wastes anaerobic biodegradability, methane production potential and microbiological composition of two experimental sanitary landfills in Brazil, running for one year, were evaluated. The two landfills showed a similar organic matter stabilization during the methane production phase, despite the high heterogeneity of the solid wastes. Both landfills presented the same level of methane (around 91.5 L CH4 / kg Volatile Total Solids and organic acids, mainly acetic and butyric acids, in the leachate. Bacterial isolates belonged to genera Megasphaera, Selenomonas, Methanobacterium, Methanobrevibacter and Methanosarcina.

  12. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    Directory of Open Access Journals (Sweden)

    Suchowska-Kisielewicz Monika

    2014-12-01

    Full Text Available An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  14. Neuronal growth and differentiation on biodegradable membranes.

    Science.gov (United States)

    Morelli, Sabrina; Piscioneri, Antonella; Messina, Antonietta; Salerno, Simona; Al-Fageeh, Mohamed B; Drioli, Enrico; De Bartolo, Loredana

    2015-02-01

    Semipermeable polymeric membranes with appropriate morphological, physicochemical and transport properties are relevant to inducing neural regeneration. We developed novel biodegradable membranes to support neuronal differentiation. In particular, we developed chitosan, polycaprolactone and polyurethane flat membranes and a biosynthetic blend between polycaprolactone and polyurethane by phase-inversion techniques. The biodegradable membranes were characterized in order to evaluate their morphological, physicochemical, mechanical and degradation properties. We investigated the efficacy of these different membranes to promote the adhesion and differentiation of neuronal cells. We employed as model cell system the human neuroblastoma cell line SHSY5Y, which is a well-established system for studying neuronal differentiation. The investigation of viability and specific neuronal marker expression allowed assessment that the correct neuronal differentiation and the formation of neuronal network had taken place in vitro in the cells seeded on different biodegradable membranes. Overall, this study provides evidence that neural cell responses depend on the nature of the biodegradable polymer used to form the membranes, as well as on the dissolution, hydrophilic and, above all, mechanical membrane properties. PCL-PU membranes exhibit mechanical properties that improve neurite outgrowth and the expression of specific neuronal markers.

  15. 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).

  16. Anaerobic and aerobic transformation of TNT

    Energy Technology Data Exchange (ETDEWEB)

    Kulpa, C.F. [Univ. of Notre Dame, IN (United States). Dept. of Biological Sciences; Boopathy, R.; Manning, J. [Argonne National Lab., IL (United States). Environmental Research Div.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  17. THE "CHEMICAL OXYGEN DEMAND / TOTAL VOLATILE ACIDS" RATIO AS AN ANAEROBIC TREATABILITY INDICATOR FOR LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    R. C. Contrera

    2015-03-01

    Full Text Available Abstract In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR. The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

  18. Removal of anaerobic soluble microbial products in a biological activated carbon reactor.

    Science.gov (United States)

    Dong, Xiaojing; Zhou, Weili; He, Shengbing

    2013-09-01

    The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3 x day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

  19. Teleosts in hypoxia : Aspects of anaerobic metabolism

    NARCIS (Netherlands)

    Van den Thillart, G.; van Waarde, Aren

    1985-01-01

    Moderate hypoxia can be tolerated by many fish species, while only some species survive severe hypoxia or anoxia. Hypoxia usually activates anaerobic glycolysis, which may be temporary when the animals are able to improve their oxygen extraction capacity. Switching over to aerobic metabolism allows

  20. [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.

  1. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  2. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  3. Biodegradation of Silk Biomaterials

    OpenAIRE

    Bochu Wang; Yang Cao

    2009-01-01

    Silk fibroin from the silkworm, Bombyx mori, has excellent properties such as biocompatibility, biodegradation, non-toxicity, adsorption properties, etc. As a kind of ideal biomaterial, silk fibroin has been widely used since it was first utilized for sutures a long time ago. The degradation behavior of silk biomaterials is obviously important for medical applications. This article will focus on silk-based biomaterials and review the degradation behaviors of silk materials.

  4. 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.

  5. Biodegradable polyesters from renewable resources.

    Science.gov (United States)

    Tsui, Amy; Wright, Zachary C; Frank, Curtis W

    2013-01-01

    Environmental concerns have led to the development of biorenewable polymers with the ambition to utilize them at an industrial scale. Poly(lactic acid) and poly(hydroxyalkanoates) are semicrystalline, biorenewable polymers that have been identified as the most promising alternatives to conventional plastics. However, both are inherently susceptible to brittleness and degradation during thermal processing; we discuss several approaches to overcome these problems to create a balance between durability and biodegradability. For example, copolymers and blends can increase ductility and the thermal-processing window. Furthermore, chain modifications (e.g., branching/crosslinking), processing techniques (fiber drawing/annealing), or additives (plasticizers/nucleating agents) can improve mechanical properties and prevent thermal degradation during processing. Finally, we examine the impacts of morphology on end-of-life degradation to complete the picture for the most common renewable polymers.

  6. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers.

  7. Postpartum anaerobic wound infection

    Directory of Open Access Journals (Sweden)

    N. A. Korobkov

    2013-01-01

    Full Text Available The objective of the study was to elucidate the role of nonclostridial anaerobic microflora in the pathogenesis of postpartum infectious and inflammatory diseases, and to choose an effective combination of antimicrobial chemotherapy. Inclusion of hyperbaric oxygen and of chemotherapy of the directed action on the obligate anaerobic flora contributed to rapid disappearance of the systemic inflammation signs and to proper involution of the uterus in 56 (86.2 % parturients in the main group. Successful treatment in the control group was observed in 44 (67.7 % patients (P=0.12.

  8. Cosmetic wastewater treatment by upflow anaerobic sludge blanket reactor

    Energy Technology Data Exchange (ETDEWEB)

    Puyol, D.; Monsalvo, V.M.; Mohedano, A.F. [Seccion de Ingenieria Quimica, Facultad de Ciencias, Universidad Autonoma de Madrid, C/ Francisco Tomas y Valiente 7, 28049, Madrid (Spain); Sanz, J.L. [Departamento de Biologia Molecular, Facultad de Ciencias, Universidad Autonoma de Madrid, C/ Francisco Tomas y Valiente 7, 28049, Madrid (Spain); Rodriguez, J.J., E-mail: juanjo.rodriguez@uam.es [Seccion de Ingenieria Quimica, Facultad de Ciencias, Universidad Autonoma de Madrid, C/ Francisco Tomas y Valiente 7, 28049, Madrid (Spain)

    2011-01-30

    Anaerobic treatment of pre-settled cosmetic wastewater in batch and continuous experiments has been investigated. Biodegradability tests showed high COD and solid removal efficiencies (about 70%), being the hydrolysis of solids the limiting step of the process. Continuous treatment was carried out in an upflow anaerobic sludge blanket reactor. High COD and TSS removal efficiencies (up to 95% and 85%, respectively) were achieved over a wide range of organic load rate (from 1.8 to 9.2 g TCOD L{sup -1} day{sup -1}). Methanogenesis inhibition was observed in batch assays, which can be predicted by means of a Haldane-based inhibition model. Both COD and solid removal were modelled by Monod and pseudo-first order models, respectively.

  9. 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.

  10. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    de Best, JH; Hunneman, P; Doddema, HJ; Janssen, DB; Harder, W; Doddema, Hans J.

    1999-01-01

    Carbon tetrachloride (52 mu M) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were somet

  11. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    Best, J.H. de; Hunneman, P.; Doddema, H.J.; Janssen, D.B.; Harder, W.

    1999-01-01

    Carbon tetrachloride (52 μM) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were sometim

  12. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    Best, J.H. de; Hunneman, P.; Doddema, H.J.; Janssen, D.B.; Harder, W.

    1999-01-01

    Carbon tetrachloride (52 μM) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were

  13. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    de Best, JH; Hunneman, P; Doddema, HJ; Janssen, DB; Harder, W; Doddema, Hans J.

    1999-01-01

    Carbon tetrachloride (52 mu M) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were somet

  14. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    Best, J.H. de; Hunneman, P.; Doddema, H.J.; Janssen, D.B.; Harder, W.

    1999-01-01

    Carbon tetrachloride (52 μM) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were sometim

  15. Solid anaerobic digestion batch of bio-waste as pre-treatment for improving amendment quality: The effect of inoculum recirculation.

    Science.gov (United States)

    Di Maria, Francesco; Segoloni, Enrico; Pezzolla, Daniela

    2016-10-01

    The effect of solid anaerobic digestion batch (SADB) on bio-waste performed with and without inoculum on the quality of the final amendment was investigated by means of determining the content of organic carbon, humic and fulvic acids and the degree of humification. Two different processes were compared: composting and SADB with post-composting. Six parallel tests were performed. In three of these tests the SADB was inoculated mixing the bio-waste with the digestate from the previous run in a 1:1 ratio by weight. The amendment obtained by the SADB with post-composting treatment, in which the SADB was not inoculated, had an organic carbon content ranging from 15.5% TS to 30.3% TS resulting from 1% up to 14% higher than that of the corresponding composting processes. Similar results were achieved for the degree of humification. On the other hand SADB in which the inoculum was used generated about 300NL/kgVS of biogas instead of about 267NL/kgVS for non-inoculated runs.

  16. Model-based design of an agricultural biogas plant: application of anaerobic digestion model no.1 for an improved four chamber scheme.

    Science.gov (United States)

    Wett, B; Schoen, M; Phothilangka, P; Wackerle, F; Insam, H

    2007-01-01

    Different digestion technologies for various substrates are addressed by the generic process description of Anaerobic Digestion Model No. 1. In the case of manure or agricultural wastes a priori knowledge about the substrate in terms of ADM1 compounds is lacking and influent characterisation becomes a major issue. The actual project has been initiated for promotion of biogas technology in agriculture and for expansion of profitability also to rather small capacity systems. In order to avoid costly individual planning and installation of each facility a standardised design approach needs to be elaborated. This intention pleads for bio kinetic modelling as a systematic tool for process design and optimisation. Cofermentation under field conditions was observed, quality data and flow data were recorded and mass flow balances were calculated. In the laboratory different substrates have been digested separately in parallel under specified conditions. A configuration of four ADM1 model reactors was set up. Model calibration identified disintegration rate, decay rates for sugar degraders and half saturation constant for sugar as the three most sensitive parameters showing values (except the latter) about one order of magnitude higher than default parameters. Finally, the model is applied to the comparison of different reactor configurations and volume partitions. Another optimisation objective is robustness and load flexibility, i.e. the same configuration should be adaptive to different load situations only by a simple recycle control in order to establish a standardised design.

  17. Evaluation of an up-flow anaerobic sludge bed (UASB) reactor containing diatomite and maifanite for the improved treatment of petroleum wastewater.

    Science.gov (United States)

    Chen, Chunmao; Liang, Jiahao; Yoza, Brandon A; Li, Qing X; Zhan, Yali; Wang, Qinghong

    2017-11-01

    Novel diatomite (R1) and maifanite (R2) were utilized as support materials in an up-flow anaerobic sludge bed (UASB) reactor for the treatment of recalcitrant petroleum wastewater. At high organic loadings (11kg-COD/m(3)·d), these materials were efficient at reducing COD (92.7% and 93.0%) in comparison with controls (R0) (88.4%). Higher percentages of large granular sludge (0.6mm or larger) were observed for R1 (30.3%) and R2 (24.6%) compared with controls (22.6%). The larger portion of granular sludge provided a favorable habitat that resulted in greater microorganism diversity. Increased filamentous bacterial communities are believed to have promoted granular sludge formation promoting a conductive environment for stimulation methanogenic Archaea. These communities had enhanced pH tolerance and produced more methane. This study illustrates a new potential use of diatomite and maifanite as support materials in UASB reactors for increased efficiency when treating refractory wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Improved Monitoring of Semi-Continuous Anaerobic Digestion of Sugarcane Waste: Effects of Increasing Organic Loading Rate on Methanogenic Community Dynamics

    Directory of Open Access Journals (Sweden)

    Athaydes Francisco Leite

    2015-09-01

    Full Text Available The anaerobic digestion of filter cake and its co-digestion with bagasse, and the effect of gradual increase of the organic loading rate (OLR from start-up to overload were investigated. Understanding the influence of environmental and technical parameters on the development of particular methanogenic pathway in the biogas process was an important aim for the prediction and prevention of process failure. The rapid accumulation of volatile organic acids at high OLR of 3.0 to 4.0 gvs·L−1·day−1 indicated strong process inhibition. Methanogenic community dynamics of the reactors was monitored by stable isotope composition of biogas and molecular biological analysis. A potential shift toward the aceticlastic methanogenesis was observed along with the OLR increase under stable reactor operating conditions. Reactor overloading and process failure were indicated by the tendency to return to a predominance of hydrogenotrophic methanogenesis with rising abundances of the orders Methanobacteriales and Methanomicrobiales and drop of the genus Methanosarcina abundance.

  19. Improved Monitoring of Semi-Continuous Anaerobic Digestion of Sugarcane Waste: Effects of Increasing Organic Loading Rate on Methanogenic Community Dynamics

    Science.gov (United States)

    Leite, Athaydes Francisco; Janke, Leandro; Lv, Zuopeng; Harms, Hauke; Richnow, Hans-Hermann; Nikolausz, Marcell

    2015-01-01

    The anaerobic digestion of filter cake and its co-digestion with bagasse, and the effect of gradual increase of the organic loading rate (OLR) from start-up to overload were investigated. Understanding the influence of environmental and technical parameters on the development of particular methanogenic pathway in the biogas process was an important aim for the prediction and prevention of process failure. The rapid accumulation of volatile organic acids at high OLR of 3.0 to 4.0 gvs·L−1·day−1 indicated strong process inhibition. Methanogenic community dynamics of the reactors was monitored by stable isotope composition of biogas and molecular biological analysis. A potential shift toward the aceticlastic methanogenesis was observed along with the OLR increase under stable reactor operating conditions. Reactor overloading and process failure were indicated by the tendency to return to a predominance of hydrogenotrophic methanogenesis with rising abundances of the orders Methanobacteriales and Methanomicrobiales and drop of the genus Methanosarcina abundance. PMID:26404240

  20. Anaerobic treatment of wastewater. Application for food industry; Depuracion anaerobia del aguas residuales. Se aplicacion en la industria alimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Carceller Rosa, J. M.

    2005-07-01

    Activated sludge aerobic reactors is a wide spread system in waste water treatment plants. Excessive proliferations of filamentous microorganisms give rise to bulking and foaming problems. Wastewater from food and drink industries as well as paper mill and related industries has severe risk of bulking episodes. Incorporation of anaerobic pre-treatment previous to existing aerobic treatment previous to existing aerobic treatment avoids bulking problems. Anaerobic systems are therefore indicated in waste waters with high concentrations of ready biodegradable organic substrates, such us waste waters from breweries, distilleries, soft drinks, paper mill industries, vegetable processing industries, etc. Basic principles of anaerobic wastewater treatment are exposed in this paper, with special reference to the most wide spread anaerobic systems: UASB, EGSB e IC reactors. Operational parameters of anaerobic and aerobic systems are compared, as well as investment and management costs, including biogas recovery. (Author) 7 refs.

  1. 膨润土改善鸡粪厌氧消化产酸产甲烷特性%Improving production characteristics of methane and organic acid during anaerobic batch digestion of poultry manure by adding bentonite

    Institute of Scientific and Technical Information of China (English)

    潘君廷; 马俊怡; 郜天磊; 邱凌; 刘宏斌

    2016-01-01

    treatment with 19.91 g VS (volatile solid) poultry manure, 3.0% bentonite addition and 20% inoculum concentration, the highest methane production was observed with methane production 301.92 mL/g, very significantly higher (P<0.05) than control group (87.8% more) and its variable cost was also the lowest with 2.43 Yuan per m3 methane among all treatments. Variable costs of methane production from anaerobic digestion of poultry manure with betonite were 0.40 to 1.68 Yuan per m3 lower than from anaerobic digestion of poultry manure only. Peak values of dissolved organic carbon (DOC) appeared five days earlier and were lower than the control group under low OLR condition. Variance of DOC, pH value and dissolved inorganic carbon (DIC) in control group was higher than treatment groups with betonite showed stability of poultry manure anaerobic digestion could be improved by bentonite addition through increasing consistent of DOC degradation. Interestingly, formic acid and propionic acid were not found during the whole anaerobic digestion process of poultry manure with betonite. Variance of acetate, lactate and n-butyrate of treatment groups with betonite were lower than the control group showing that betonite addition could enhance the stability of anaerobic digestion process of poultry manure. Organic loading rate was the key factor of anaerobic digestion of poultry manure with bentonite under low OLR condition. Amount of betonite was the key factor of poultry manure anaerobic digestion with bentonite under high OLR condition. Inoculum concentration and OLR had significant interaction on acetate concentration. Organic loading rate had significant effect on lactate concentration. No interactions of these three factors were found on lactate concentration.%为探究膨润土对鸡粪厌氧消化过程中产甲烷特性和可溶性有机酸代谢特性的影响,采用L8(23)正交试验设计,以鸡粪添加量(有机负荷率)、膨润土添加量和接

  2. 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

  3. 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.

  4. 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

  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. Biomarkers of Microbial Metabolism for Monitoring in-situ Anaerobic PAH Degradation

    Science.gov (United States)

    Young, L.; Phelps, C.; Battistelli, J.

    2002-12-01

    Monoaromatic and polycyclic aromatic compounds found in petroleum and its products are subject to biodegradation in the absence of oxygen. These anaerobic pathways reveal novel mechanism of microbial transformation through a series of metabolites and intermediates which are unique to the anaerobic degradation process. The presence of these compounds in-situ, then conceptually can serve as indicators that anaerobic degradation is taking place. We have laboratory studies and field samples which support this concept for BTX and PAH compounds. Environments in which these anaerobic degradation processes have been observed include freshwater and estuarine sediments, groundwater from impacted aquifers at a former manufactured gas plant and gasoline station, and a creosote-contaminated aquifer. Analytical protocols were developed to detect nanomolar concentrations from soil slurries and groundwater samples and microcosm studies verified their formation from field samples and use as biomarkers of activity. Recent studies on the mechanisms of anaerobic naphthalene and methylnaphthalene metabolism have identified several unusual compounds that can serve as biomarkers for monitoring in situ PAH biodegradation. For naphthalene these include 2-naphthoic acid (2-NA), tetrahydro-2-naphthoic acid (TH-2-NA), hexahydro-2-naphthoic acid (HH-2-NA) and methylnaphthoic acid (MNA) generated by sulfate-reducing bacteria degrading naphthalene or methylnaphthalene. Groundwater samples were analyzed from wells distributed throughout an anaerobic, creosote-contaminated aquifer and also from a leaking underground storage site. Samples were extracted, derivatized and analyzed by GC/MS. The concentration of 2-NA at each monitoring well was quantified and correlated to the zones of naphthalene contamination. Taken together with measurements of the aquifer's physical characteristics, these biomarker data can be used to describe the extent of naphthalene biodegradation at these site.

  7. Biodegradable and compostable alternatives to conventional plastics

    National Research Council Canada - National Science Library

    J. H. Song; R. J. Murphy; R. Narayan; G. B. H. Davies

    2009-01-01

    .... Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality...

  8. Anaerobic fermentation of beef cattle manure. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, A.G.; Chen, Y.R.; Varel, V.H.

    1981-01-01

    The research to convert livestock manure and crop residues into methane and a high protein feed ingredient by thermophilic anaerobic fermentation are summarized. The major biological and operational factors involved in methanogenesis were discussed, and a kinetic model that describes the fermentation process was presented. Substrate biodegradability, fermentation temperature, and influent substrate concentration were shown to have significant effects on CH/sub 4/ production rate. The kinetic model predicted methane production rates of existing pilot and full-scale fermentation systems to within 15%. The highest methane production rate achieved by the fermenter was 4.7 L CH/sub 4//L fermenter day. This is the highest rate reported in the literature and about 4 times higher than other pilot or full-scale systems fermenting livestock manures. Assessment of the energy requirements for anaerobic fermentation systems showed that the major energy requirement for a thermophilic system was for maintaining the fermenter temperature. The next major energy consumption was due to the mixing of the influent slurry and fermenter liquor. An approach to optimizing anaerobic fermenter designs by selecting design criteria that maximize the net energy production per unit cost was presented. Based on the results, we believe that the economics of anaerobic fermentation is sufficiently favorable for farm-scale demonstration of this technology.

  9. High rate anaerobic thermophilic technologies for distillery wastewater treatment.

    Science.gov (United States)

    Pérez-García, M; Romero-García, L I; Rodríguez-Cano, R; Sales-Márquez, D

    2005-01-01

    In this paper, performance of two high rate technologies, upflow anaerobic fixed-film reactor and fluidized bed laboratory-scale, treating distillery wastewater (wine vinasses) at anaerobic thermophilic conditions have been compared. The results obtained show that the stationary packed bed, with a corrugated plastic support, operated under stable conditions at organic loading rates (OLR0) around 20 kgCOD/m3/d, gives maximal total CODr of 76% at OLR0 of 6.29 kgCOD/m3/d; the fluidized bed reactor, operated on open pore sintered-glass media, gives total CODr of 96% at OLR0 of 5.88 kgCOD/m3/d. The anaerobic fluidized bed technology is more effective than the upflow anaerobic fixed-film technology due, fundamentally, to this technology favouring the transport of microbial cells from the bulk to the surface and enhancing the contact between the microorganism-substrate phases, In this sense, the stationary packed bed technology is adequate for the treatment of easily biodegradable wastewater, or for the cases where elevated percentages of CODr removal are not required, while the fluidized bed technology is especially suitable for treatment of hazardous wastes with recalcitrant compositions.

  10. The ecology of anaerobic degraders of BTEX hydrocarbons in aquifers.

    Science.gov (United States)

    Lueders, Tillmann

    2017-01-01

    The degradation of benzene, toluene, ethylbenzene and xylene (BTEX) contaminants in groundwater relies largely on anaerobic processes. While the physiology and biochemistry of selected relevant microbes have been intensively studied, research has now started to take the generated knowledge back to the field, in order to trace the populations truly responsible for the anaerobic degradation of BTEX hydrocarbons in situ and to unravel their ecology in contaminated aquifers. Here, recent advances in our knowledge of the identity, diversity and ecology of microbes involved in these important ecosystem services are discussed. At several sites, distinct lineages within the Desulfobulbaceae, the Rhodocyclaceae and the Gram-positive Peptococcaceae have been shown to dominate the degradation of different BTEX hydrocarbons. Especially for the functional guild of anaerobic toluene degraders, specific molecular detection systems have been developed, allowing researchers to trace their diversity and distribution in contaminated aquifers. Their populations appear enriched in hot spots of biodegradation in situ (13)C-labelling experiments have revealed unexpected pathways of carbon sharing and obligate syntrophic interactions to be relevant in degradation. Together with feedback mechanisms between abiotic and biotic habitat components, this promotes an enhanced ecological perspective of the anaerobic degradation of BTEX hydrocarbons, as well as its incorporation into updated concepts for site monitoring and bioremediation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs.

    Science.gov (United States)

    Jones, D M; Head, I M; Gray, N D; Adams, J J; Rowan, A K; Aitken, C M; Bennett, B; Huang, H; Brown, A; Bowler, B F J; Oldenburg, T; Erdmann, M; Larter, S R

    2008-01-10

    Biodegradation of crude oil in subsurface petroleum reservoirs has adversely affected the majority of the world's oil, making recovery and refining of that oil more costly. The prevalent occurrence of biodegradation in shallow subsurface petroleum reservoirs has been attributed to aerobic bacterial hydrocarbon degradation stimulated by surface recharge of oxygen-bearing meteoric waters. This hypothesis is empirically supported by the likelihood of encountering biodegraded oils at higher levels of degradation in reservoirs near the surface. More recent findings, however, suggest that anaerobic degradation processes dominate subsurface sedimentary environments, despite slow reaction kinetics and uncertainty as to the actual degradation pathways occurring in oil reservoirs. Here we use laboratory experiments in microcosms monitoring the hydrocarbon composition of degraded oils and generated gases, together with the carbon isotopic compositions of gas and oil samples taken at wellheads and a Rayleigh isotope fractionation box model, to elucidate the probable mechanisms of hydrocarbon degradation in reservoirs. We find that crude-oil hydrocarbon degradation under methanogenic conditions in the laboratory mimics the characteristic sequential removal of compound classes seen in reservoir-degraded petroleum. The initial preferential removal of n-alkanes generates close to stoichiometric amounts of methane, principally by hydrogenotrophic methanogenesis. Our data imply a common methanogenic biodegradation mechanism in subsurface degraded oil reservoirs, resulting in consistent patterns of hydrocarbon alteration, and the common association of dry gas with severely degraded oils observed worldwide. Energy recovery from oilfields in the form of methane, based on accelerating natural methanogenic biodegradation, may offer a route to economic production of difficult-to-recover energy from oilfields.

  12. Effect of humic acid in leachate on specific methanogenic activity of anaerobic granular sludge.

    Science.gov (United States)

    Guo, Mengfei; Xian, Ping; Yang, Longhui; Liu, Xi; Zhan, Longhui; Bu, Guanghui

    2015-01-01

    In order to find out the effects of humic acid (HA) in anaerobic-treated landfill leachate on granular sludge, the anaerobic biodegradability of HA as well as the influences of HA on the total cumulative methane production, the anaerobic methanization process and the specific methanogenic activity (SMA) of granular sludge are studied in this paper. Experimental results show that as a non-biodegradable organic pollutant, HA is also difficult to be decomposed by microbes in the anaerobic reaction process. Presence of HA and changes in the concentration have no significant influences on the total cumulative methane production and the anaerobic methanization process of granular sludge. Besides, the total cumulative methane production cannot reflect the inhibition of toxics on the methanogenic activity of granular sludge on the premise of sufficient reaction time. Results also show that HA plays a promoting role on SMA of granular sludge. Without buffering agent the SMA value increased by 19.2% on average due to the buffering and regulating ability of HA, while with buffering agent the SMA value increased by 5.4% on average due to the retaining effect of HA on the morphology of the sludge particles. However, in the presence of leachate the SMA value decreased by 27.6% on average, because the toxic effect of the toxics in the leachate on granular sludge is much larger than the promoting effect of HA.

  13. Microbial-based evaluation of anaerobic membrane bioreactors (AnMBRs) for the sustainable and efficient treatment of municipal wastewater

    KAUST Repository

    Harb, Moustapha

    2017-03-01

    Conventional activated sludge-based wastewater treatment is an energy and resource-intensive process. Historically it has been successful at producing safely treated wastewater effluents in the developed world, specifically in places that have the infrastructure and space to support its operation. However, with a growing need for safe and efficient wastewater treatment across the world in both urban and rural settings, a paradigm shift in waste treatment is proving to be necessary. The sustainability of the future of wastewater treatment, in a significant way, hinges on moving towards energy neutrality and wastewater effluent reuse. This potential for reuse is threatened by the recent emergence and study of contaminants that have not been previously taken into consideration, such as antibiotics and other organic micropollutants (OMPs), antibiotic resistance genes, and persistent pathogenic bacteria. This dissertation focuses on investigating the use of anaerobic membrane bioreactor (AnMBR) technology for the sustainable treatment of municipal-type wastewaters. Specifically, a microbial approach to understanding biofouling and methane recovery potential in anaerobic MBR systems has been employed to assess different reactor systems’ efficiency. This dissertation further compares AnMBRs to their more widely used aerobic counterparts. This comparison specifically focuses on the removal and biodegradation of OMPs and antibiotics in both anaerobic and aerobic MBRs, while also investigating their effect on the proliferation of antibiotic resistance genes. Due to rising interest in wastewater effluent reuse and the lack of a comprehensive understanding of MBR systems’ effects on pathogen proliferation, this dissertation also investigates the presence of pathogens in both aerobic and anaerobic MBR effluents by using molecularbased detection methods. The findings of this dissertation demonstrate that membrane-associated anaerobic digestion processes have significant

  14. A review on introduction and applications of starch and its biodegradable polymers

    OpenAIRE

    Shanta Pokhrel

    2015-01-01

    Biodegradable polymers play a very important role in plastic engineering by replacing non biodegradable, non renewable petrol based polymers. Starch is a renewable, biodegradable, low cost natural polymer with high availability. Natural polymers can be blended with synthetic polymers to improve their properties significantly. This article reviews advance in starch and starch based blends and presents their numerous potential applications. Therefore, this review helps to understand the importa...

  15. On the efficiency of the hybrid and the exact second-order sampling formulations of the EnKF: a reality-inspired 3-D test case for estimating biodegradation rates of chlorinated hydrocarbons at the port of Rotterdam

    Science.gov (United States)

    Gharamti, Mohamad E.; Valstar, Johan; Janssen, Gijs; Marsman, Annemieke; Hoteit, Ibrahim

    2016-11-01

    This study considers the assimilation problem of subsurface contaminants at the port of Rotterdam in the Netherlands. It involves the estimation of solute concentrations and biodegradation rates of four different chlorinated solvents. We focus on assessing the efficiency of an adaptive hybrid ensemble Kalman filter and optimal interpolation (EnKF-OI) and the exact second-order sampling formulation (EnKFESOS) for mitigating the undersampling of the estimation and observation errors covariances, respectively. A multi-dimensional and multi-species reactive transport model is coupled to simulate the migration of contaminants within a Pleistocene aquifer layer located around 25 m below mean sea level. The biodegradation chain of chlorinated hydrocarbons starting from tetrachloroethene and ending with vinyl chloride is modeled under anaerobic environmental conditions for 5 decades. Yearly pseudo-concentration data are used to condition the forecast concentration and degradation rates in the presence of model and observational errors. Assimilation results demonstrate the robustness of the hybrid EnKF-OI, for accurately calibrating the uncertain biodegradation rates. When implemented serially, the adaptive hybrid EnKF-OI scheme efficiently adjusts the weights of the involved covariances for each individual measurement. The EnKFESOS is shown to maintain the parameter ensemble spread much better leading to more robust estimates of the states and parameters. On average, a well tuned hybrid EnKF-OI and the EnKFESOS respectively suggest around 48 and 21 % improved concentration estimates, as well as around 70 and 23 % improved anaerobic degradation rates, over the standard EnKF. Incorporating large uncertainties in the flow model degrades the accuracy of the estimates of all schemes. Given that the performance of the hybrid EnKF-OI depends on the quality of the background statistics, satisfactory results were obtained only when the uncertainty imposed on the background

  16. On the efficiency of the hybrid and the exact second-order sampling formulations of the EnKF: a reality-inspired 3-D test case for estimating biodegradation rates of chlorinated hydrocarbons at the port of Rotterdam

    KAUST Repository

    El Gharamti, Mohamad

    2016-11-15

    This study considers the assimilation problem of subsurface contaminants at the port of Rotterdam in the Netherlands. It involves the estimation of solute concentrations and biodegradation rates of four different chlorinated solvents. We focus on assessing the efficiency of an adaptive hybrid ensemble Kalman filter and optimal interpolation (EnKF-OI) and the exact second-order sampling formulation (EnKFESOS) for mitigating the undersampling of the estimation and observation errors covariances, respectively. A multi-dimensional and multi-species reactive transport model is coupled to simulate the migration of contaminants within a Pleistocene aquifer layer located around 25 m below mean sea level. The biodegradation chain of chlorinated hydrocarbons starting from tetrachloroethene and ending with vinyl chloride is modeled under anaerobic environmental conditions for 5 decades. Yearly pseudo-concentration data are used to condition the forecast concentration and degradation rates in the presence of model and observational errors. Assimilation results demonstrate the robustness of the hybrid EnKF-OI, for accurately calibrating the uncertain biodegradation rates. When implemented serially, the adaptive hybrid EnKF-OI scheme efficiently adjusts the weights of the involved covariances for each individual measurement. The EnKFESOS is shown to maintain the parameter ensemble spread much better leading to more robust estimates of the states and parameters. On average, a well tuned hybrid EnKF-OI and the EnKFESOS respectively suggest around 48 and 21 % improved concentration estimates, as well as around 70 and 23 % improved anaerobic degradation rates, over the standard EnKF. Incorporating large uncertainties in the flow model degrades the accuracy of the estimates of all schemes. Given that the performance of the hybrid EnKF-OI depends on the quality of the background statistics, satisfactory results were obtained only when the uncertainty imposed on the background

  17. Removal of antibiotics from piggery wastewater by biological aerated filter system: Treatment efficiency and biodegradation kinetics.

    Science.gov (United States)

    Chen, Jun; Liu, You-Sheng; Zhang, Jin-Na; Yang, Yong-Qiang; Hu, Li-Xin; Yang, Yuan-Yuan; Zhao, Jian-Liang; Chen, Fan-Rong; Ying, Guang-Guo

    2017-08-01

    This study aimed to investigate the removal efficiency and mechanism for antibiotics in swine wastewater by a biological aerated filter system (BAF system) in combination with laboratory aerobic and anaerobic incubation experiments. Nine antibiotics including sulfamonomethoxine, sulfachloropyridazine, sulfamethazine, trimethoprim, norfloxacin, ofloxacin, lincomycin, leucomycin and oxytetracycline were detected in the wastewater with concentrations up to 192,000ng/L. The results from this pilot study showed efficient removals (>82%) of the conventional wastewater pollutants (BOD5, COD, TN and NH3-N) and the detected nine antibiotics by the BAF system. Laboratory simulation experiment showed first-order dissipation kinetics for the nine antibiotics in the wastewater under aerobic and anaerobic conditions. The biodegradation kinetic parameters successfully predicted the fate of the nine antibiotics in the BAF system. This suggests that biodegradation was the dominant process for antibiotic removal in the BAF system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Kraft pulp and paper mill wastewater treatment using fixed bed anaerobic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Damianovic, M. H. R. Z; Ruas, D.; Pires, E. C.; Foresti, E.

    2009-07-01

    The effluents of pulp mills contain a myriad of toxic compounds, biodegradable organic matter and sulfur compounds. to decrease the amount of fresh water required for pulp and paper production closed circuits are in use, however, higher concentrations of slat, as oxidized sulfur compounds, are encountered in the wastewaters. energy costs and new environmental concerns are motivating the use of anaerobic pretreatment as a way to decrease energy expenditure in the treatment plant together with lower sludge production. In anaerobic environment, the organic matter removal can follow methanogenic or sulfidogenic paths and with the latter simultaneous reduction of the oxidized sulfur compounds also occurs. (Author)

  19. [Biodegradable catheters and urinary stents. When?

    Science.gov (United States)

    Soria, F; Morcillo, E; López de Alda, A; Pastor, T; Sánchez-Margallo, F M

    2016-10-01

    One of the main wishes in the field of urinary catheters and stents is to arm them with biodegradable characteristics because we consider a failure of these devices the need for retrieval, the forgotten catheter syndrome as well as the adverse effects permanent devices cause after fulfilling their aim. The efforts focused in new designs, coatings and biomaterials aim to increase the biocompatibility of theses internal devices. Lately, there have been correct advances to answer the main challenges regarding biodegradable ureteral devices. Thus, modulation of the rate of degradation has been achieved thanks to new biomaterials and the use of copolymers that enable to choose the time of permanence as it is programmed with conventional double J catheters. Biocompatibility has improved with the use of new polymers that adapt better to the urine. Finally, one of the main problems is elimination of degraded fragments and experimentally it has be demonstrated that new designs elicit controlled degradation, from distal to proximal; using stranding and combination of copolymers degradation may be caused by dilution, reducing fragmentation to the last stages of life of the prosthesis. Moreover, it has been demonstrated that biodegradable catheters potentially may cause less urinary tract infection, less encrustation and predictably they will diminish catheter morbidity, since their degradation process reduces adverse effects. Regarding the development of biodegradable urethral stents, it is necessary to find biomaterials that enable maintaining their biomechanical properties in the long term, keeping open the urethral lumen both in patients with BPH and urethral stenosis. Modulation of the time of degradation of the prosthesis has been achieved, but the appearance of urothelial hyperplasia is still a constant in the initial phases after implantation. The development of drug eluting stents, anti-proliferative or anti-inflammatory, as well as biodegradable stents biocoated is a

  20. Biodegradable micromechanical sensors

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Greve, Anders; Schmid, Silvan

    of mechanical and thermal properties of polymers. For example, measurements of the resonance frequency of cantilevers were used to characterize thin polymer coatings in various environmental conditions [2]. Also, the influence of humidity on the Young’s modulus of SU-8 was evaluated [3]. However, introduction...... of biopolymers to microfabrication is challenging, as these polymers are affected by common processes such as photolithography or wet etching. Here, we present two methods for fabrication of biodegradable micromechanical sensors. First, we fabricated bulk biopolymer microcantilevers using nanoimprint lithography...