Anaerobic Digestion Of Cattle Manure Research Articles

Variation in Methane Yield from Anaerobic Digestion of Cattle Manure

Variation in Methane Yield from Anaerobic Digestion of Cattle Manure

Biotic and abiotic roles of leachate recirculation in batch mode solid-state anaerobic digestion of cattle manure

Solid state anaerobic digestion, with leachate recirculation, is suitable for exploiting manure with a high solid content. The biotic and abiotic effects of the leachates were studied in lab-scale leach bed reactors (LBRs). LBRs were fed with cow manure and four leachates either biologically active or inert. The biotic impact of leachate was assessed by monitoring the microbial communities in the manure and in the leachates. LBRs with biologically active leachates, regardless to their origin, produced equivalent methane volumes (114.52±19.05 and 99.79±6.4NL/kgVS) while LBRs with inert leachates produced half less methane (60.22±5.71 and 58.87±13.2NL/kgVS) attesting to the biotic role of leachate. Moreover, its beneficial abiotic role is mainly due to its initial nutrient content, pH, and buffering capacity. The microbial community in the manure was strongly involved in methane production, and no transfer of microorganisms from the liquid phase was found (p<0.05).

The efficiency of shredded and briquetted wheat straw in anaerobic co-digestion with dairy cattle manure

Anaerobic co-digestion of cattle manure (CM) with shredded or briquetted wheat straw (SS and BS, respectively) was evaluated in thermophilic continuously stirred tank reactors (CSTR) in two experiments (lab and full-scale). Three lab-scale CSTR (15 l) were used with 20 days hydraulic retention time (HRT); one was fed with CM and the other two with mixtures of CM (95% of fresh matter, FM) and SS or BS (5% FM). In the second experiment, two full-scale CSTR (30 m3) were operated with 25 days HRT; one reactor was fed with CM and the other with CM + BS (9% FM). Ultimate CH4 yield was analysed from each substrate. Biochemical CH4 potential at 21 days for CM, SS and BS were 128; 187 and 200 lSTP [CH4] kg−1 [VS]. Anaerobic digestion of CM, CM + SS and CM + BS in lab-scale reactors yielded 165; 214 and 217 lSTP [CH4] kg−1 [VS]. In full scale-reactors, CM and CM + BS yielded 264 and 351 lSTP [CH4] kg−1 [VS]. Increments of 31 and 33% on CH4 yield were achieved in CM + BS compared to CM in lab and full-scale reactors, respectively. Regarding the energy balance, the energy yields were the same for both reactors using straw as co-substrate (CM + SS and CM + BS) after subtracting the energy consumption of the pretreatment, corresponding to 1100 kWh of net energy output. However, briquetting technology could be advantageous for biogas plants where the straw might be transported over longer distances, due to reduction of the transportation costs.

Seasonal Variation on Microbial Community and Methane Production during Anaerobic Digestion of Cattle Manure in Brazil.

Anaerobic digestion is an alternative method for the treatment of animal manure and wastewater. The anaerobic bioconversion of biomass requires a multi-step biological process, including microorganisms with distinct roles. The diversity and composition of microbial structure in pilot-scale anaerobic digestion operating at ambient temperature in Brazil were studied. Influence of the seasonal and temporal patterns on bacterial and archaeal communities were assessed by studying the variations in density, dynamic and diversity and structure. The average daily biogas produced in the summer and winter months was 18.7 and 16 L day(-1), respectively, and there was no difference in the average methane yield. Quantitative PCR analysis revealed that no differences in abundances and dynamics were found for bacterial communities and the total number of Archaea in different seasons. Analysis of bacterial clone libraries revealed a predominance of Firmicutes (54.5 %/summer and 46.7 %/winter) and Bacteroidetes (31.4 %/summer and 44.4 %/winter). Within the Archaea, the phylum Euryarchaeota was predominant in both digesters. Phylogenetic distribution showed changes in percentage between the phyla identified, but no alterations were recorded in the quality and amount of produced methane or community dynamics. The results may suggest that redundancy of microbial groups may have occurred, pointing to a more complex microbial community in the ecosystem related to this ambient temperature system.

The sustainability of anaerobic digestion plants: a win–win strategy for public and private bodies

Energy production from the anaerobic digestion of organic waste is widely recognized as a social and environmental opportunity, since it allows reducing waste disposal and making waste management economically profitable. However, profitability of these plants is strongly affected by the quantity and the quality of wastes, as well as by the availability of local subsidies. The key role of incentive policies in the economic success of investments in biomass to energy plants is highly recognised and has led European Union (EU) governments to promote the deployment of these plants. Incentive policies adopted in EU countries differ significantly. In this paper, an evaluation model based on cost-benefit analysis is developed in order to identify the production-based incentive rates making investments in anaerobic digestion plant economically feasible without reducing social and environmental positive impacts. The model has been applied to the case of energy production plants from anaerobic digestion of cattle manure. In order to investigate the influence of the plant size on the investment profitability, different waste collection areas have been considered. Environmental performances of the plants have been evaluated by adopting a life cycle assessment approach. Results obtained confirm the environmental benefits achievable through the energy production from the anaerobic digestion of cattle manure. However, the current production-based incentive rates provided in most EU Countries revealed an inadequate balance between private and public interest, since they make profitable the investments only in case of small plants.

Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology.

In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10 m3 and 16 l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days).Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH4) yield, as well as better percentage of ultimate CH4 yield retrieved and lower residual CH4 emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident.Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability.

Analysis and behavior of colistin during anaerobic fermentation

A new analytical method for the determination of colistin in fermenter samples was developed followed by a study on the behavior of this substance during anaerobic fermentation. Analysis of colistin A and B was carried out by liquid chromatography–tandem mass spectrometry. Separation of the analytes was performed on a Security Guard column (4×3mm). Fourteen fermentation tests in batch as well as in continuous reactors were carried out. After 44days of anaerobic digestion of cattle manure, initially spiked with 500mg/kg of colistin sulfate, a considerable decrease of the colistin concentration to less than 1mg/kg could be observed. Furthermore, the daily production of biogas and methane was measured. A correlation between gas production and colistin concentration could not be determined. However, an increase of 10% of the cumulative methane production was observed in those fermenters spiked with an initial bolus of 500mg/kg colistin.

Bioreactor Performance in the Anaerobic Digestion of Cattle Manure: A Review

A literature review has been undertaken to investigate the potential of anaerobic digestion for material recovery and energy production from cattle manure. These wastes constitute 8–20% total solid, with a volatile solid content of 70–85%. The biodegradable fractions include about 11% hemicellulose, 26–53% cellulose, and 11% lignin. Anaerobic digestion of cattle manure was studied under various operating conditions using different types of bioreactors and it allows the conversion of 50–75% of organic matter to methane with an organic loading rate of 1–6 g VS/L day. Continuous two-stage configuration involving a first-stage thermophilic reactor and mesophilic second reactor emerges to be superior and the most effective technologies for anaerobic digestion of cattle manure. It was demonstrated that 41% of volatile solids were converted to methane at an organic loading rate of 5.82 g VS/L day. The methane yield was found to be 620 L/kg VS added.

Acidification of non-medicated and oxytetracycline-medicated cattle manures during anaerobic digestion

Possible adverse effects of a commonly used veterinary antibiotic, oxytetracycline (OTC), on acidogenic phase of anaerobic digestion of cattle manure along with optimum operating conditions were investigated. A standard veterinary practice of 50 ml OTC solution (20 mg/kg cattle weight) was injected into the muscles of cattle and then manure samples were collected for 5 days following the injection. The 5-day samples were equally mixed and used throughout digestion experiments. Preliminary batch tests were conducted to obtain the optimum pH range and observe volatile fatty acids (VFAs) production. In this regard, different sets of batch digesters were operated at pH ranging from 5.2±0.1 to 5.8±0.1 at mesophilic conditions with total solids content of 6.0±0.2%. The pH of 5.5±0.1 was found to be the optimum value for acidification for both non-medicated and OTC-medicated conditions. Under predetermined conditions, maximum total VFA (VFAtot) of 830±3 mg (as acetic acid)/L was produced and maximum acidification rate was evaluated as 11% for OTC-medicated cattle manure, whereas they were 900±6 mg (as acetic acid)/L and 12% for non-medicated manure. Digestion studies were further continued in a semi-continuous mode at pH 5.5±0.1 and SRT/HRT of 5 days. VFAtot concentrations and maximum acidification rate increased up to 2181±19 mg (as acetic acid)/L and 29% for non-medicated cattle manure. For OTC-medicated cattle manure, lower acidification rate of 18% was observed.

Prevalence and persistence of potentially pathogenic and antibiotic resistant bacteria during anaerobic digestion treatment of cattle manure

Anaerobic digestion figures as a sustainable alternative to avoid discharge of cattle manure in the environment, which results in biogas and biofertilizer. Persistence of potentially pathogenic and drug-resistant bacteria during anaerobic digestion of cattle manure was evaluated. Selective cultures were performed for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC). Antimicrobial susceptibility patterns were determined and a decay of all bacterial groups was observed after 60days. Multidrug-resistant bacteria were detected both the influent and effluent. GPC, the most prevalent group was highly resistant against penicillin and levofloxacin, whereas resistance to ampicillin, ampicillin-sulbactam and chloramphenicol was frequently observed in the ENT and NFR groups. The data point out the need of discussions to better address management of biodigesters and the implementation of sanitary and microbiological safe treatments of animal manures to avoid consequences to human, animal and environmental health.

Numerical study of microbial population dynamics in anaerobic digestion through the Anaerobic Digestion Model No. 1 (ADM1)

In this study, the interactions between the microbial populations in an anaerobic digester leading to the acidification of the fermentation medium were investigated using numerical simulation in the Anaerobic Digestion Model No. 1 (ADM1). The anaerobic digestion of cattle manure at 10g volatile solids (VSs)/L and 35°C was used as the case study. The numerical runs were performed using a factorial experimental approach with two levels. The minimum pH reached in the digestion was considered the response variable, whereas the initial concentrations of the main microbial groups included in the ADM1 were considered the factors. The statistical analysis demonstrated that the initial concentration of acetoclastic bacteria was the most critical variable in the acidification of the medium. It was estimated that permanent acidification occurred when the initial concentration of this group of microorganisms was less than or equal to 0.0838g chemical oxygen demand (COD)/L, regardless of the population density of the other microbial groups.

Influence of palm oil mill effluent as inoculum on anaerobic digestion of cattle manure for biogas production

Anaerobic digestion for palm oil mill effluent (POME) is widely known for its potential in biogass production. In this study, the potential of using cattle manure for biogas production in complete mix anaerobic bioreactor was investigated using POME at unregulated pH and temperature. Two identical bioreactors were used in this study; namely R1 and R2 fed with cattle manure without and with POME as inoculum, respectively. Both bioreactors were allowed for five days to run in batch mode followed by semi continuous operations at HRT of 20 days. R2 produced 41% methane content compared to 18% produced in R1. A better COD percentage reduction of 45% was found in R2 which was operated with POME as inoculum compared to R1 with 35%. These results indicated that POME as inoculum has an influence on the start-up time and the rate of biogas produced.This findings will help in waste reduction.

Methanogenic Community Dynamics during Anaerobic Utilization of Agricultural Wastes

This work is devoted to the investigation of the methanogenic archaea involved in anaerobic digestion of cattle manure and maize straw on the basis of terminal restriction fragment length polymorphism (T-RFLP) analysis of archaeal 16S rRNA genes. The biological diversity and dynamics of methanogenic communities leading to anaerobic degradation of agricultural organic wastes with biogas production were evaluated in laboratory-scale digesters. T-RFLP analysis, along with the establishment of archaeal 16S rRNA gene clone libraries, showed that the methanogenic consortium consisted mainly of members of the generaMethanosarcinaandMethanoculleus,with a predominance ofMethanosarcinaspp. throughout the experiment.

Gold Nanoparticle Clusters in Quasinematic Layers of Liquid-Crystalline Dispersion Particles of Double-Stranded Nucleic Acids

The interaction between gold nanoparticles and particles of cholesteric liquid-crystalline dispersions formed by double-stranded DNA and poly(I)×poly(C) molecules is considered. It is shown that small-sized (~ 2 nm) gold nanoparticles induce two different structural processes. First, they facilitate the reorganization of the spatial cholesteric structure of the particles into a nematic one. This process is accompanied by a fast decrease in the amplitude of an abnormal band in the CD spectrum. Second, they induce cluster formation in a "free space" between neighboring nucleic acid molecules fixed in the structure of the quasinematic layers of liquid-crystalline particles. This process is accompanied by slow development of the surface plasmon resonance band in the visible region of the absorption spectrum. Various factors influencing these processes are outlined. Some assumptions concerning the possible mechanism(s) of fixation of gold nanoparticles between the neighboring double-stranded nucleic acid molecules in quasinematic layers are formulated.

Particle-size effect of CuO and ZnO on biogas and methane production during anaerobic digestion

The effects of bulk- and nano-sized CuO and ZnO particles on biogas and methane production during anaerobic digestion of cattle manure were studied for a period of 14 days at 36 °C using the ISO 13641-2 guidelines. Biogas production was severely affected at concentrations of bulk and nanoparticles over 120 and 15 mg/L for CuO and 240 and 120 mg/L for ZnO, respectively. EC50 concentrations for methane inhibition were estimated to be 129 mg Cu/L for bulk CuO, 10.7 mg Cu/L for nano CuO, 101 mg Zn/L for bulk ZnO and 57.4 mg Zn/L for nano ZnO. The solubility of CuO nanoparticles in the reaction mixture was observed after 14 days of incubation and was significantly higher than the levels observed for ZnO. These results are of significant importance, as it is the first time that the effects of metal oxide particle size on biogas and methane production have been studied.

Effect of operational parameters on anaerobic co‐digestion of dairy cattle manure and agricultural residues: A case study for the Kahramanmaraş region in Turkey

AbstractThe aim of this study was to investigate the effect of temperature and hydraulic retention time (HRT) on anaerobic co‐digestion/biomethanation of cattle manure and agricultural residues (clover, grass and wheat straw). For this purpose, 12 semi‐continuous reactors, fed with/without agricultural residues, were operated under varied temperature (10+, 20+ and 35±1°C) and HRT (20 and 30 days) conditions. During the experimental study, all reactors were fed once on a daily basis and operated with an organic loading rate of 3 g volatile solids (VS)/L×d. Daily biogas production, pH, biogas composition, volatile fatty acids, chemical oxygen demand and solids' (dry matter andVS) concentrations were analyzed. Results indicate that the effect of agricultural residue addition did not influence the rate and extent of biomethanation of cattle manure. An effect of temperature was clearly observed on reactor performance for both operational HRTs of 20 and 30 days. At 35±1°C, reactors produced 299–324 mL biogas/g VS added, whereas this value remained between 87–138 mL biogas/g VS for the reactors run at 20+ °C. The results were comparable to the studies performed on anaerobic digestion of cattle manure in terms of both methane production yield (39–182 mL CH4/g VS added) and dry matter reduction efficiencies (33–51%).

Digestion of cattle manure: Thermogravimetric kinetic analysis for the evaluation of organic matter conversion

Anaerobic digestion of cattle manure was studied under thermophilic and mesophilic conditions with the purpose of evaluating the effect of temperature on the quality of the final digestate. Non-isothermal thermogravimetric kinetic analysis was applied for assessing organic matter conversion of biological stabilization. The mathematical approximation proves to be a useful tool for evaluating the differences attained during biological degradation. The anaerobic digestion of the organic substrate resulted in a reduction of the activation energy value obtained from the different applied kinetic models. Results obtained from thermal kinetic analysis were in accordance with those from the monitoring of the anaerobic digestion process. The higher values of methane yield reported for the mesophilic digestion in comparison to that of the thermophilic indicated a greater capability of the former process in the utilization of substrate and thus a higher conversion of organic matter which can be quantified by the activation energy value.

Analysis of small-scale biogas utilization systems on Ontario cattle farms

The production of biogas through the anaerobic digestion of cattle manure and its subsequent use in the generation of electricity on larger farms in Ontario is currently economically attractive. This is a result of the Ontario Feed-In Tariff (FIT) program, which provides incentivized rates for the production of electricity from biogas. Although larger farms can take advantage of the higher rates for electricity, there are substantially more smaller farms for which individually designed and engineered biogas systems would be prohibitively expensive. By employing the concept of modular biogas plants, this analysis evaluates the economics of small-scale biogas utilization systems. Dairy farms with at least 33 animals and beef farms with at least 78 animals can operate economically attractive biogas systems. This analysis shows that approximately 9000 additional Ontario cattle farms would be able to take advantage of the FIT program, which would add 120 MW e of renewable energy capacity to the Ontario electrical grid.

Effects of organic wastes digestion for biogas production on mineral nutrient availability of biogas effluents

Organic farming systems are characterized by the strong regulation of the import of nutrients into the farming system to replace nutrient losses via sold products. In the present study mineral nutrient flows and balances of P, K and magnesium (Mg) were analysed for a mixed organic cropping system with dairy husbandry and for a stockless organic farming system. Also the influence of biogas digestion of farmyard residues (stable wastes, crop residues, etc.) as well as the effect of the import of substrates for biogas digestion on plant mineral nutrient uptake and farmgate nutrient balances was analysed. The objectives of the current study were; (1) to study the effects of anaerobic digestion of cattle manure and crop residues on plant mineral nutrient uptake; and (2) to model nutrient flows and balances related to the input of different kind of substrates for biogas digestion at the farmgate. Results indicated that slurry digestion did not influence plant P and K uptake. Import of single allowed substrates for digestion would lead to large imbalances in nutrient inputs compared to withdrawals. Most of the suited substrates for biogas digestion were associated with large K surpluses and insufficient P returns in comparison to mineral nutrient outputs via sold animal and plant products.

牛ふん尿のメタン発酵における食品廃棄物投入の効果

食品廃棄物が牛ふん尿のメタン発酵に及ぼす影響を三大栄養成分別に調べるために，たんぱく質，炭水化物，脂質をそれぞれ主成分としたプロテイン，パン粉，バターを牛ふん尿とともに有効容積6Lの発酵槽に投入し，水理学的平均滞留日数30日の中温連続メタン発酵実験を行った。発酵性能の低下が発生しない食品廃棄物の限界VS負荷は，パン粉2.2gVS/L・day，バター2.4gVS/L・day，プロテイン0.8gVS/L・dayであった。食品廃棄物の投入VSあたり平均メタンガス発生量はバターが最も大きく0.82L/gVS，次いでパン粉0.42L/gVS，プロテイン0.31L/gVSの順であった。プロテインのメタンガス発生量は理論値の54%と低かった。たんぱく質の共発酵では発酵阻害物質であるアンモニアが発生するためと考えられる。食品廃棄物のメタンガス濃度はバターが最も高く68%，次いでプロテイン64%，パン粉57%であった。