Anaerobic Co-digestion Of Cow Manure Research Articles

Optimization of the Factors Affecting Biogas Production Using the Taguchi Design of Experiment Method

The present study analyzed the effect of temperature, pH, pre-treatment and mixing ratio on the anaerobic digestion process. The parameters during the anaerobic co-digestion of cow manure and food waste were then optimized using the Taguchi experimental design method. ANOVA was carried out to find the significant parameters which influence biogas production. Experimental tests were carried out at laboratory-scale reactors kept at different temperatures (28 °C, 35 °C, and 50 °C). The specific methanogenic performance (SMP) during anaerobic digestion at higher temperatures was characterized with the analysis of acetate, propionate, butyrate, hydrogen, glucose, and formate, and was validated with the literature. The improvement of biogas production with different pre-treatments, i.e., ultrasonic, autoclave, and microwave techniques, was also analyzed. The results showed that the reactor that was maintained at 35 °C showed the highest biogas production, while the reactor that was maintained at a lower temperature (28 °C) produced the lower volume of biogas. As the retention time increases, the amount of biogas production increases. Methanogenic activities of microorganisms were reduced at higher temperature conditions (65 °C). Biogas production increased by 28.1%, 20.23%, and 13.27% when the substrates were treated with ultrasonic, autoclave, and microwave, respectively, compared to the untreated substrate. The optimized condition for the highest biogas production during anaerobic co-digestion of food waste and cow manure is a temperature of 35 °C, a pH of 7 and a mixing ratio (CM:FW = 1.5:0.5). ANOVA showed that temperature is the most important input parameter affecting biogas production, followed by mixing ratio.

Impact of Iron Oxide Nanoparticles on Anaerobic Co-Digestion of Cow Manure and Sewage Sludge

Supplementation with iron oxide nanoparticles has been suggested as a potential method for improving energy generation through anaerobic digestion, specifically by enhancing the rate of methane production. This investigation examined the effects of iron oxide (Fe3O4) nanoparticles (NPs) on anaerobic co-digestion of cow manure (CM) and sewage sludge (SS) through batch testing conducted under mesophilic conditions (35 °C) using a RESPIROMETRIC Sensor System 6 Maxi—BMP (RSS-BMP). The use of Fe3O4 nanoparticles at doses of 40, 80, 120, and 160 mg/L (batches M1, M2, M3, and M5) was studied. The use of 160 mg/L Fe3O4 nanoparticles in combination with mixtures of different ratios (M4, M5, and M6) was further investigated. The findings indicate that the addition of Fe3O4 nanoparticles at a concentration of 40 mg/L to anaerobic batches did not significantly impact the hydrolysis process and subsequent methane production. Exposing the samples to Fe3O4 NPs at concentrations of 80, 120, and 160 mg/L resulted in a similar positive effect, as evidenced by hydrolysis percentages of approximately 94%, compared to 60% for the control (C2). Furthermore, methane production also increased. The use of Fe3O4 nanoparticles at a concentration of 160 mg/L resulted in biodegradability of 97.3%, compared to 51.4% for the control incubation (C2). Moreover, the findings demonstrate that supplementing anaerobic batches with 160 mg/L Fe3O4 NPs at varying mixture ratios (M4, M5, and M6) had a significant impact on both hydrolysis and methane production. Specifically, hydrolysis percentages of 94.24, 98.74, and 96.78% were achieved for M4, M5, and M6, respectively, whereas the percentages for the control incubation (C1, C2, and C3) were only 56.78, 60.21, and 58.74%. Additionally, the use of 160 mg/L Fe3O4 NPs in mixtures M4, M5, and M6 resulted in biodegradability percentages of 78.4, 97.3, and 88.3%, respectively. In contrast, for the control incubation (C1, C2, and C3) biodegradability was only 44.24, 51.4, and 49.1%.

Anaerobic Co-Digestion of Cow Manure and Palm Oil Mill Effluent (POME): Assessment of Methane Production and Biodegradation Efficiency

The performance of anaerobic co-digestion of cow manure and POME was evaluated. The anaerobic composting process was carried out by using semi-continuous reactors under the mesophilic condition (35 ± 1℃). The addition of POME to the on-going anaerobic composting of cow manure was applied stepwise within a cycle of HRT (20 days). Results showed that the anaerobic co-digestion reactor could produce methane at about six times higher (7.2 L CH4) than the control reactor (1.3 L CH4). An increasing of POME loaded to the on-going anaerobic composting cow manure culture (4% to 64%) did not affect pH of the culture in which pH was still stable between 7.11 and 7.5. Assessment of biodegradation efficiency revealed that nitrogen removal of the anaerobic co-digestion reactor was six times higher (21%) than the nitrogen removal of the control reactor (3.4%). This suggested that the anaerobic co-digestion reactor performed sufficiently well in which no organic acid as well as ammonia accumulated in the reactor that could be effective to decompose the organic matters.

Recognize the benefit of continuous anaerobic co-digestion of cow manure and sheep manure from the perspective of metabolic pathways as revealed by metatranscriptomics

Anaerobic digestion (AD) of cow manure (CM) has been extensively implemented for simultaneous waste disposal and biogas generation. Within this criteria, AD co-digestion of CM and sheep manure (SM) was proved a viable approach for improved methane production. However, concrete evidence regarding the relationship between substrate catabolism and microbial metabolism is lacking, hindering the understanding of the merits of co-digestion. This study adopted metatranscriptomics to unveil critical metabolisms in the co-digestion scenario. Co-digestion significantly improved cellulase activity (CM + SM: 1.031; CM alone: 0.485–0.675) in lignocellulose hydrolysis. Concurrently, the introduction of SM promoted variable enzymes in protein metabolism (serine and cysteine) to intermediates (pyruvate and Acetyl-CoA) in acidogenesis and acetogenesis. Consequently, co-digestion rendered the improved Coenzyme-B sulfoethylthiotransferase activity (CM + SM: 3.883; CM alone: 1.702–1.864), thus excellent methanogenesis (20% improvement compared with CM alone). The results emphasized that co-digestion of CM and SM improved lignocellulose and certain protein hydrolysis to intermediates, thus enhancing methanogenesis.

Coconut-shell-derived bio-based carbon enhanced microbial electrolysis cells for upgrading anaerobic co-digestion of cow manure and aloe peel waste

Microbial electrolysis cells (MECs) and exogenous accelerants can augment anaerobic digestion performance. Herein, MECs and coconut-shell-derived bio-based carbon (CBC) accelerant are adopted to strengthen anaerobic co-digestion of cow manure and aloe peel waste. The MEC with the voltage of 0.6 V and CBC accelerant of 0.15 wt.% gained the highest cumulative biogas yield (444.20 NmL/g VS) and chemical oxygen demand removal rate (75.46%), which are 80.25% and 58.33% higher than those (246.44 NmL/g VS, 47.66%) of the blank group, respectively. The digestates embodied a utilization potential with thermogravimetric loss of 37.12%–50.67% and total nutrient content of 35.36–51.58 g/kg. These results benefited from excellent electrocatalytic activity of MECs and physicochemical properties of CBC accelerant. A general strategy for understanding improved methanogenesis was proposed based on integrated effects of MECs and CBC accelerant. This work will shed light on development of anaerobic co-digestion by combining MECs and bio-based carbon accelerants.

Modeling the Methane Production Kinetics of Anaerobic Co-Digestion of Agricultural Wastes Using Sigmoidal Functions

The modified sigmoidal bacteria growth functions (the modified Gompertz, logistic, and Richards) were used to evaluate the methane production process kinetics of agricultural wastes. The mesophilic anaerobic co-digestion experiments were conducted with various agricultural wastes as feedstocks, including cow manure, corn straw, grape leaves, vines, wine residue, strawberry leaves, and tomato leaves. The results showed that anaerobic co-digestion of cow manure and other agricultural wastes increased the methane yields while it prolonged the lag phase time. Compared with the modified Gompertz and logistic models, the modified Richards model obtained higher correlation coefficients and was able to fit experimental data better. The results of this study were expected to determine a suitable model to simulate and study the kinetic process of anaerobic co-digestion with mixed agricultural wastes as feedstocks.

Co-digestion of cow and sheep manure: Performance evaluation and relative microbial activity

This study evaluated the performance of anaerobic co-digestion of cow manure (CM) and sheep manure (SM) in both batch and continuous digesters at 37 °C. Synergistic effects of co-digesting CM and SM at varying volatile solids (VS) ratios (1:0, 0:1, 3:1, 1:1, 1:3) were observed in the batch experiment, with the most effective degradation of cellulose (56%) and hemicellulose (55%), and thus, the highest cumulative methane yield (210 mL/gVSadded) obtained at a CM:SM ratio of 1:3. Co-digesting CM and SM improved the hydrolysis, as evidenced by the cellulase brought by SM and the increases of cellulolytic bacteria Clostridium. Besides, co-digestion enhanced the acidogenesis and methanogenesis, reflected by the enrichment of syntrophic bacteria Candidatus Cloacimonas and hydrogenotrophic archaea Methanoculleus (Coenzyme-B sulfoethylthiotransferase). When testing continuous digestion, the methane yield increased from 146 mL/gVS/d (CM alone) to 179 mL/gVS/d (CM:SM at 1:1) at a constant organic loading rate (OLR) of 1g VS/L/d and a hydraulic retention time (HRT) of 25 days. Furthermore, the anaerobic digestion process was enhanced when the daily feed changed back to CM alone, reflected by the improved daily methane yield (159 mL/VS/d). These results provided insights into the improvement of methane production during the anaerobic digestion of animal manure.

Biological pretreatment with Trametes versicolor to enhance methane production from lignocellulosic biomass: A metagenomic approach

The presence of poorly biodegradable components in lignocellulosic biomass limits the methane recovery in anaerobic digesters. The main reason to go for aerobic pretreatment before anaerobic digestion (AD) is to enable enzymatic cleavage of the aromatic rings in lignin by oxygen since it cannot be efficiently degraded under anaerobic conditions. In this study, the advantage of highly-cellulolytic white-rot fungi Trametes versicolor was taken by aerobic pretreatment prior to anaerobic co-digestion of cow manure and selected cereal crop materials (i.e. wheat, rye, barley, triticale) harvested at different stages. Fungal pretreatment improved the methane yield by 10%–18% and cellulose degradation up to 80%. Furthermore, higher volatile fatty acid (VFA) speciation was found in the anaerobic digesters upon fungal pretreatment. 16S rRNA gene amplicon sequencing revealed a more diverse microbial community in the fungal-pretreated anaerobic digesters. Generally, typically-detected bacterial species dominated the digesters; except that Synergistetes was only enriched in the fungal-pretreated digesters. Although Methanosarcianease was the predominant methanogenic archaea, a more diverse methanogenic population was identified in the fungal-pretreated digesters in which Methanobacteriaceaa and Methanomibrobiaceae also took role during biomethanation. Comparatively more unique microbiome of biogas reactors upon fungal pretreatment synergistically affected VFA production, cellulose degradation and eventually methane yield in an affirmative way. Considering the functional importance of bacterial and methanogenic archaeal populations, elevated knowledge of the microbial structures is essential for minimizing process failures and for creating strategies for process optimization of lignocellulose based-AD.

Crop-based composting of lignocellulosic digestates: Focus on bacterial and fungal diversity

In this study, organic matter degradation and microbial diversity were assessed during the composting of lignocellulose-rich digestates. Digestates were collected based on each crop type during anaerobic co-digestion of cow manure and barley, triticale, wheat and rye. Bacterial and fungal diversity in digestate composting systems were determined by 16S and 18S rRNA gene amplicon sequencing, respectively. Crop-based composting of anaerobic digestates showed similar process trends in terms of pH, temperature, moisture content (MC) and C:N ratio. The properties of final compost products were in accordance with the national legislations regarding soil applications, except MC, which were therefore air-dried before being amended to soil. Most abundant bacterial genera were represented by Luteimonas, Bacillus, Ochrobactrum and Thermobifida. Meanwhile, Thermomyces, Aspergillus, Galactomyces and Neurospora were detected as the predominant fungal genera in all compost samples.

Fungal bioaugmentation of anaerobic digesters fed with lignocellulosic biomass: What to expect from anaerobic fungus Orpinomyces sp.

Energy-efficient biogas reactors are often designed and operated mimicking natural microbial ecosystems such as the digestive tracts of ruminants. Anaerobic fungi play a crucial role in the degradation of lignocellulose-rich fiber thanks to their high cellulolytic activity. Fungal bioaugmentation is therefore at the heart of our understanding of enhancing anaerobic digestion (AD). The efficiency of bioaugmentation with anaerobic fungus Orpinomyces sp. was evaluated in lignocellulose-based AD configurations. Fungal bioaugmentation increased the methane yield by 15–33% during anaerobic co-digestion of cow manure and selected cereal crops/straws. Harvesting stage of the crops was a decisive parameter to influence methane production together with fungal bioaugmentation. A more efficient fermentation process in the bioaugmented digesters was distinguished by relatively-higher abundance of Synergistetes, which was mainly represented by the genus Anaerobaculum. On the contrary, the composition of the methanogenic archaea did not change, and the majority of methanogens was assigned to Methanosarcina.

Mesophilic anaerobic co-digestion of cow manure with three-phase olive mill solid waste

ABSTRACTThe biogas production potential of different mixtures of cow manure (CM) and three-phase olive mill solid waste (3POMSW) at 37°C was evaluated. Results showed that 3POMSW produced more methane yield than CM. In the anaerobic co-digestion (AcoD) methane yield increased with increasing of 3POMSW content, the maximum methane yield was observed at 3POMSW:CM ratio of 3:1. Addition of an enzyme mixture (Celluclast, Pulpzyme HC, Sherazyme, Novozym 342, and Resinase A 2X) to the 1:1 mixture increased the quantity and quality of biogas production and reduced the retention time required to achieve a high rate of biodegradation. Therefore, AcoD with enzymes was an effective way to improve the methane yield of 3POMSW and CM.

Different approaches to assess the environmental performance of a cow manure biogas plant

In intensive livestock production areas, farmers must apply manure management systems to comply with governmental regulations. Biogas plants, as a source of renewable energy, have the potential to reduce environmental impacts comparing with other manure management practices. Nevertheless, manure processing at biogas plants also incurs in non-desired gas emissions that should be considered. At present, available emission calculation methods cover partially emissions produced at a biogas plant, with the subsequent difficulty in the preparation of life cycle inventories. The objective of this study is to characterise gaseous emissions: ammonia (NH3-N), methane (CH4), nitrous oxide (N2Oindirect, and N2Odirect) and hydrogen sulphide (H2S) from the anaerobic co-digestion of cow manure by using different approaches for preparing gaseous emission inventories, and to compare the different methodologies used. The chosen scenario for the study is a biogas plant located next to a dairy farm in the North of Catalonia, Spain. Emissions were calculated by two methods: field measurements and estimation, following international guidelines. International Panel on Climate Change (IPCC) guidelines were adapted to estimate emissions for the specific situation according to Tier 1, Tier 2 and Tier 3 approaches. Total air emissions at the biogas plant were calculated from the emissions produced at the three main manure storage facilities on the plant: influent storage, liquid fraction storage, and the solid fraction storage of the digestate. Results showed that most of the emissions were produced in the liquid fraction storage. Comparing measured emissions with estimated emissions, NH3, CH4, N2Oindirect and H2S total emission results were in the same order of magnitude for both methodologies, while, N2Odirect total measured emissions were one order of magnitude higher than the estimates. A Monte Carlo analysis was carried out to examine the uncertainties of emissions determined from experimental data, providing probability distribution functions. Four emission inventories were developed with the different methodologies used. Estimation methods proved to be a useful tool to determine emissions when field sampling is not possible. Nevertheless, it was not possible to establish which methodology is more reliable. Therefore, more measurements at different biogas plants should be evaluated to validate the methodologies more precisely.

Effects of Substrate Loading Rate in Anaerobic Co-digestion of Cow Manure and Energy Crops

Effects of Substrate Loading Rate in Anaerobic Co-digestion of Cow Manure and Energy Crops

Study on improving anaerobic co-digestion of cow manure and corn straw by fruit and vegetable waste: Methane production and microbial community in CSTR process

Based on continuous anaerobic co-digestion of cow manure with available carbon slowly released corn straw, the effect of adding available carbon quickly released fruit and vegetable waste (FVW) was explored, meanwhile microbial community variation was studied in this study. When the FVW added was 5% and 1%, the methane production of the cow manure and corn straw was improved, and the start-up process was shortened. With higher proportion of FVW to 5%, the performance was superior with a mean methane yield increase of 22.4%, and a greater variation of bacterial communities was observed. FVW enhanced the variation of the bacterial communities. The microbial community structure changed during fermentation and showed a trend toward a diverse and balance system. Therefore, the available carbon quickly released FVW was helpful to improve the anaerobic co-digestion of the cow manure and available carbon slowly released corn straw.

Biogas production from anaerobic co-digestion of cow manure with kitchen waste and Water Hyacinth

The prime objective of this paper was to analyze and compare biogas production from various sources of waste material. The Renewable Energy Policy envisions that 5% of total energy production needs to be achieved by 2015 and 10% by 2020. This work focuses on the comparative study of the production of biogas through anaerobic co-digestion utilizing abandoned resources of biomass. Materials under study were Cow manure, Sewage Sludge, Kitchen Waste & Water Hyacinth. Experiments were conducted under mesophilic condition (37 °C) with 1.5 wt%NaOH to obtain the desirable pH. The loading ratio of each batch was maintained as 1:1 on both experiments. Kitchen Waste and Cow Manure showed promising results till about the 120th hour following plummeting production of biogas. Total production for 1 L batch of Water Hyacinth, Cow Manure & Sewage Sludge was 812 ml with 65%Methane, 14%CO and 21%other gases obtained after 800 h, while Kitchen Waste & Cow Manure provided 335 ml consisting of 60%Methane, 18%CO & 22%other gases within the same time frame. Results indicated that addition of Sewage Sludge with the widely used Cow Manure can lead to accelerated reaction, increased production and an improved methane content.

Kinetic and Enhancement of Biogas Production For The Purpose of Renewable Fuel Generation by Co-digestion of Cow Manure and Corn Straw in A Pilot Scale CSTR System

Biogas production from anaerobic co-digestion of cow manure (CM) and corn straw residue (CSR) were experimentally investigated using a completely stirred tank reactor (CSTR) under semi- continuously feeding circumstance at mesophilic (35°C±2) temperature. The pilot-scale digester with 180 L in volume was employed under experimental protocol to examine the effect of the change in organic loading rate on efficiency of biogas production and to report on its steady-state performance. An average organic loading rates of 2 and 3 kg VS. (m-3.d-1) and a hydraulic retention time (HRT) of 25 days was examined with respect to two different CM to CSR mixing ratios of 100:0 , 75:25 and 50:50, respectively. The results showed both organic loading rates at co-digestion of CM+ CSR gave better methane yields than single digestion of cow manure. The biogas production efficiency was obtained 0.242, 0.204, 0.311 0.296, 259.5 and 235 m3.(kg VS input)-1 for 2 and 3 kg VS.(m-3.d-1) at CM to CSR mixing ratios of100:0 , 75:25 and 50:50, respectively. The reactor showed stable performance with VS reduction between 55-74% during different runs. With increment of loading rate, the VS degradation and biogas yield decreased. Modified Gompertz and logistic plot equation was employed to model the methane production at different organic loading rates and substrate concentrations. The equations gave a good approximation of the maximum methane production (rm) and the methane yield potential (P) with correlation coefficient (R2) over 0.99.Article History: Received Oct 25th 2016; Received in revised form Dec 19th 2016; Accepted 2nd January 2017; Available onlineHow to Cite This Article: Taghinazhad. J., Abdi, R. and Adl, M. (2017). Kinetic and Enhancement of Biogas Production for the purpose of renewable fuel generation by Co-digestion of Cow Manure and Corn Straw in a Pilot Scale CSTR System. Int Journal of Renewable Energy Development, 6(1),37-44http://dx.doi.org/10.14710/ ijred.6.1.37-44

Study on the bio-methane yield and microbial community structure in enzyme enhanced anaerobic co-digestion of cow manure and corn straw

The use of enzymes to improve anaerobic co-digestion (AcoD) of cow manure and corn straw was explored in this study, including cellulase pretreatment and direct additions of amylase and protease. The effects of enzymes on microbial community structure were investigated though PCR-DGGE method. Results showed that AcoD with amylase achieved the highest methane yield of 377.63ml·CH4/g·VS, which was an increase of 110.79%. The methane increment consumed the amylase of 4.18×10−5g/ml·CH4. Enzymes mainly affected the bacteria in the hydrolysis stage rather than the bacteria in the hydrogenesis and acetogenesis stage and the archaea in the methanogenesis stage. However, the experimental results demonstrated that enzymes had no negative influence on microbial communities; the predominant microbial communities were similar. Therefore, AcoD with amylase was an effective way to improve the bio-methane yield of cow manure and corn straw.

SEMI-CONTINUOUS ANAEROBIC CO-DIGESTION OF COW MANURE AND BANANA WASTE: EFFECTS OF MIXTURE RATIO

Anaerobic co-digestion of cow manure (CM) and banana waste (BW) was investigated. The experiments have been carried out and were tested for different mixture ratios of CM:BW in terms of volatile solids : 100:0, 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100 with the aim to maximize methane yield and methane production from the anaerobic co-digestion of cow manure and banana waste. The results obtained show that a maximum methane yield of 229 mLSTP/g VS added was obtained at a (CM): (BW) ratio of was 40:60 with a biodegradability of 86% for an organic loading rate in the range of 1.49- 3.57 kg waste mixture/(m 3

Semi-continuous anaerobic co-digestion of cow manure and steam-exploded Salix with recirculation of liquid digestate

The effects of recirculating the liquid fraction of the digestate during mesophilic anaerobic co-digestion of steam-exploded Salix and cow manure were investigated in laboratory-scale continuously stirred tank reactors. An average organic loading rate of 2.6 g VS L−1 d−1 and a hydraulic retention time (HRT) of 30 days were employed. Co-digestion of Salix and manure gave better methane yields than digestion of manure alone. Also, a 16% increase in the methane yield was achieved when digestate was recirculated and used instead of water to dilute the feedstock (1:1 dilution ratio). The reactor in which the larger fraction of digestate was recirculated (1:3 dilution ratio) gave the highest methane yields. Ammonia and volatile fatty acids did not reach inhibitory levels, and some potentially inhibitory compounds released during steam explosion (i.e., furfural and 5-hydroxy methyl furfural) were only detected at trace levels throughout the entire study period. However, accumulation of solids, which was more pronounced in the recycling reactors, led to decreased methane yields in those systems after three HRTs. Refraining from the use of fresh water to dilute biomass with a high-solids content and obtaining a final digestate with increased dry matter content might offer important economic benefits in full-scale processes. To ensure long-term stability in such an approach, it would be necessary to optimize separation of the fraction of digestate to be recirculated and also perform proper monitoring to avoid accumulation of solids.

Development of simplified anaerobic digestion models (SADM's) for studying anaerobic biodegradability and kinetics of complex biomass

The anaerobic co-digestion of cow manure and waste paper at ambient temperature condition was observed to be optimized at a mix proportion of 75:25 respectively. The development and testing of a set of simplified anaerobic digestion models (SADM's) for this mixture revealed that the Hill's based biogas yield rate model was most appropriate in describing the kinetics of biogas production. Parameter estimation using non-linear regression revealed that the half saturation constants expressed as acidified substrate and volatile solids equivalents were 0.228g/L and 5.340gVS/L respectively, and the maximum specific biogas yield rate and biodegradability were 2.2mL/gVS/day and 0.313 respectively. The coefficients “n” and “m” indicative of acidogenic bacterial adaptation for degradation and acetogenic/methanogenic bacterial cooperativity were estimated to be 1.360 and 2.738 respectively, while hydrolysis/acidogenesis was considered the rate limiting step. The need of bacterial adaptation may be an important factor to consider during anaerobic modeling of complex biomass.