Anaerobic Co-digestion Of Cattle Manure Research Articles

Anaerobic Co-Digestion of Cattle Manure with Ruminal Waste to Increase Biogas Production

Cattle manure (CM) is mostly used as an inoculum in order to start-up of agricultural biogas plants or as a co-substrate in the anaerobic digestion of lignocellulosic content. Rumen fluid microbiota is also considered to be effective in lignocellulose digestion. It is known that microorganisms in the ruminal waste facilitate the hydrolysis of lignocellulosic structures. However, there are few studies on the inoculum effect of rumen microorganisms on bioreactor performances when rumen content is used as co-substrate and inoculum together with cattle manure, and it is not clear how rumen waste can be used in various anaerobic digestion systems. In this study, biogas production efficiencies obtained from lignocellulosic content in mono and cosubstrate (1:1 and 1:2 Volatile Solids) bioreactors formed by using ruminal waste (RW) and CM microbial communities were investigated. In order to determine the biogas production efficiencies, biomethane potential (BMP) experiments that simulate anaerobic digestion process conditions in a laboratory environment were applied. Treatment with 50% application of RW cosubstrate, 65.51% biogas and 70.64% methane production efficiency increases were achieved compared to monosubstrate CM bioreactor.

Enhanced anaerobic co-digestion of cattle manure with food waste and pig manure: Statistical optimization of pretreatment condition and substrate mixture ratio

This study investigated the optimal pretreatment condition and mixture ratio of cattle manure (CM) for its efficient anaerobic co-digestion (AcoD) with food waste (FW) and pig manure (PM). The pretreatment performances of thermal (TM), microwave (MW), and ultrasound (US) technologies and the AcoD performance were statistically and experimentally evaluated at various mixture ratios of CM, FW, and PM. The results revealed that the most effective pretreatment condition with the TM, MW, and US pretreatments was 129.3 °C for 49.6 min, 824.2 W for 7.3 min, and 418.0 W for 36.3 min, respectively. The best AcoD performance of optimally pretreated CM (PCM) was achieved when 30.5 % PCM was mixed with 42.5 % FW and 27.0 % PM. A long-term evaluation showed that the start-up rate for the anaerobic mono-digestion of PCM was 2.3 times faster than that of CM and the amount of methane produced was 4.7 times higher; process stability was thus preferentially maintained under a higher organic loading rate (OLR) (2.0 kg-VS/m3∙d). The start-up rate for the AcoD of PCM with FW and PM was 1.2 times higher than that of the AcoD of CM with FW and PM. Although the performance gap between the AcoD reactors after steady state was not significantly different, the PCM AcoD reactor provided a more stable operation under a higher OLR (5.0 kg-VS/m3∙d). This study demonstrates that the pretreatment and co-digestion of CM could significantly enhance the production of biogas and improve process stability.

Anaerobic Co-Digestion of Cattle Manure and Brewer’s Residual Yeast: Process Stability and Methane and Hydrogen Sulfide Production

Anaerobic co-digestion (AcoD) of animal waste and agro-industrial by-products has been widely studied and employed to increase biogas production potential and enhance process stability. This study evaluated the AcoD of cattle manure (CM) and brewer’s residual yeast (RY) in semi-continuous biodigesters, focusing on energy potential (biogas and methane yields) and process stability. Four treatments were assessed, each with different proportions (% of volatile solids) of CM and RY: 100:0, 88:12, 78:22, and 68:32. Trials were conducted in 30-L tubular reactors at room temperature with a hydraulic retention time of 30 days. The inclusion of RY led to a gradual rise in biogas and methane production, with more significant reductions in solid content than mono-digestion of CM. The addition of RY resulted in daily CH4 production increases of 18.5, 32.3, and 51.9% for treatments with 12, 22, and 32% of RY, respectively, compared to the control treatment. Therefore, AcoD demonstrated a higher potential for energy recovery. However, RY introduced elevated H2S levels in the biogas. Caution is advised when adding this co-substrate to AcoD due to potential process influence and biogas application restrictions.

Bioaugmentation with cold-tolerant methanogenic culture to boost methane production from anaerobic co-digestion of cattle manure and corn straw at 20℃

Low methane yield and long digestion period are common issues encountered in psychrophilic anaerobic digestion (AD). To address these challenges, this study successfully acclimatized a cold-tolerant methanogenic consortium and applied it as bioaugmentation seed to enhance the psychrophilic AD. Various doses (4%, 8%, 12%, 14%, and 16%) of the bioaugmentation seed were introduced to boost the batch psychrophilic AD of cattle manure and corn straw. Results demonstrated that bioaugmentation increased the methane yield by 3.4–4.8-fold, shortened T80 time by 28–34 d, and reduced VFAs contents by 21.61%-49.23%. The optimal dose for bioaugmentation on psychrophilic AD was 12%, increasing methane yield from 15.40 mL g-1VS to 73.01 mL g-1VS. Microbial community analysis revealed that increase in relative abundance of propionate-oxidizing bacteria and the dominant methanogens (Methanosarcina, Methanothrix) were the key to accelerating the rate-limiting step, i.e., conversion of accumulated propionate and acetate to methane. These findings suggest that bioaugmentation with cold-tolerant methanogenic consortium is a potential approach to boost the psychrophilic AD process, and provide theoretical guidance for commercial biogas plants in cold regions.

Effect of temperature and the Carbon-Nitrogen (C/N) ratio on methane production through anaerobic co-digestion of cattle manure and Jatropha seed cake

Anaerobic digestion is a method of agricultural residue transformation used in bioenergy, making these activities energy efficient. However, it can be limited on a larger scale by the availability and diversity of organic residues related to carbon-nitrogen (C/N). Therefore, the anaerobic co-digestion of bovine manure and Jatropha seed cake (Jatropha curcas) were evaluated, with three different C/N ratios, under two conditions: mesophilic (30ºC) and thermophilic (50ºC). Biodigesters were mounted with three replicates for each C/N ratio. The highest production of CH4 was registered after 30 days of processing in the thermophilic condition (C/N 25:1) with 633.95 ± 5.59 mL of CH4 g-1 VS. In contrast, the lowest production was in the mesophilic condition (C/N 20:1) with 208.66 ± 2.61 mL of CH4 g-1 VS. The feasibility of co-digestion of agricultural residues in the production of CH4 as a possible bioenergetic alternative in short periods was demonstrated.

Transport and retention modeling of the liquid phase through a stratified porous leach-bed. Application for solid-state anaerobic co-digestion of cattle manure and roadside grass

The recirculation flow inside the leach-bed during solid-state anaerobic co-digestion of layered cattle manure and roadside grass was characterized using three different methods on lab scale reactors. Tracing experiments and method of moments were used to characterize percolation flow properties with different leach-bed compositions and a new criterion was proposed to quantitatively evaluate the ratio between preferential pathways and dead volumes for each experiment. The impact of recirculation flow on leach-bed complexity for different moments of SS-AD and substrate layering was characterized using steady-state reactor modeling and the impact of recirculation flow on microporosity and macroporosity evolutions all along SS-AD was determined using modeling of hydrodispersive parameters. It appeared that layering and time could significantly impact percolation flow and leach-bed complexity, until 36 % of residence time variation and 110 % of leach-bed complexity. Moreover, layering could impose a different percolation flow for each layer and cause a preferential pathways disruption.

Bioaugmentation improves batch psychrophilic anaerobic co-digestion of cattle manure and corn straw

Low temperatures result in poor anaerobic digestion (AD). To investigate whether bioaugmentation can improve anaerobic co-digestion of cattle manure and corn straw at 20 °C, five different doses of methanogenic propionate-degrading culture (4%, 8%, 12%, 14%, and 16%) were added to batch AD systems to compare bioaugmentation performance. The results showed that the methane production of all the bioaugmented digesters was enhanced compared to the control, increasing 2.80–4.20-fold with digestion times (T80) shorter by 11–22 d. The recommended dose for biogas production was 14%, and the recommended dose for the highest bioaugmentation efficiency of microbes was 4%. These improvements were due to the addition of methanogenic propionate-degrading culture, which alleviated volatile fatty acids (VFA) accumulation, especially that of acetate and propionate. Metagenomic sequencing analysis indicated that the increased proportion of propionate-oxidizing bacteria, syntrophic butyrate-oxidizing bacteria, and acetoclastic methanogens in bioaugmentation reactors may be responsible for better AD performance.

Anaerobic Co-Digestion of Cattle Manure and Raw Algae: Kinetic Study and Optimization of Methane Potential by RSM

Anaerobic Co-Digestion of Cattle Manure and Raw Algae: Kinetic Study and Optimization of Methane Potential by RSM

Bioaugmentation Improves Batch Psychrophilic Anaerobic Co-Digestion of Cattle Manure and Corn Straw

Bioaugmentation Improves Batch Psychrophilic Anaerobic Co-Digestion of Cattle Manure and Corn Straw

Effect of hydraulic retention time on anaerobic co-digestion of cattle manure and food waste

Anaerobic digestion of cattle manure has a low efficiency due to the high hydraulic retention time (HRT) required to degrade the abundant degradation-resistant compositions, co-digestion with food waste is effective at improving the methane production. Lowering the HRT can therefore increase the methanogenic efficiency during co-digestion. This study considered the effects of different HRTs (25, 20, 15, 10, 7, 5, and 4 days) on cattle manure and food waste co-digestion. The highest methane production was achieved at 1.48 L/L/d with an HRT of 5 days. The maximum methane yields (236–257 mL/g-VS) were attained at HRT ≥15 days and decreasing the HRT to 10-5 days resulted in low methane yields and complete process failure at HRT 4 days, due to volatile fatty acids accumulated and microorganisms washed out. From a high HRT of 20 days to a low HRTs of 5 days, Bacteroidetes and Firmicutes were the dominant bacteria and the percentage of syntrophic acetate oxidizing bacteria (mainly Pelotomaculum and Pseudothermotoga) clearly increased. The dominant methanogen changed from the acetotrophic Methanosaeta to the hydrogenophilic Methanobrevibacter. These results enable biogas plants to utilize surplus amounts of cow manure and food waste in a sustainable manner with high process capacity and methane recovery.

Anaerobic co-digestion of cattle manure and liquid fraction of digestate (LFD) pretreated corn stover: Pretreatment process optimization and evolution of microbial community structure

Liquid fraction of digestate (LFD) was used to pretreat corn stover to enhance the biomethane production of anaerobic co-digestion (AcoD) with cattle manure. The effects of LFD concentration and water content (WC) for pretreatment on co-digestion performance and microbial community structure were investigated in a batch system. Results showed that the cumulative biomethane yield (CBY) for co-digestion was improved by 16.85%–41.78% compared with the control. The highest biomethane yield of 238.25 mL g VS−1 was obtained at 85% WC for pretreatment and a 5 M LFD concentration, and this yield was 41.78% higher than that in the control. The LFD pretreatment enriched the dominant bacterial phyla (Firmicutes and Bacteroidetes), but had little influence on the prevalent archaeal genus (Euryarchaeota). This study demonstrated that LFD pretreatment can greatly enhance the biomethane yield of co-digestion of corn stover and cattle manure under optimal parameters.

Techno-Economic Assessment of Anaerobic Co-digestion of Cattle Manure and Wheat Straw (Raw and Pre-treated) at Small to Medium Dairy Cattle Farms

Anaerobic digestion of dairy cattle manure is a common practice; however, the low biogas yield of manure can hamper the profitability of anaerobic digestion systems in small to medium dairy cattle farms . To make this technology more attractive to farmers, an increase in biogas yield per cubic meter of reactor could be achieved by co-digesting animal manure with co-substrates such as straw (in its raw form or pre-treated). A Techno-economic assessment of anaerobic co-digestion of cattle manure and raw and briquetted straw has been carried out. The results obtained from the techno-economic assessment showed that for a farm of 250 adult cattle heads the revenues generated in an anaerobic mono-digestion process are not able to offset the initial required investment. However, the co-digestion of manure with raw or briquetted straw showed better economic performance and positive returns (net present values > 0, internal rate of return > 9% and a RETURN of the investment in 11 years) for farmers willing to implement anaerobic digestion. Electricity selling price, and the price of the straw are the key parameters to determine the profitability of the system. Moreover, pre-treatments to increase the straw biogas production have been assessed and evaluated from a technic and economic perspective. Alkali and microwave-alkali straw pre-treatments showed the best results with an increase in biogas production of 156% and 92% compared to raw straw.

Two-stage thermophilic anaerobic co-digestion of corn stover and cattle manure to enhance biomethane production

Two-stage thermophilic anaerobic co-digestion of cattle manure and corn stover was conducted to increase biomethane production. The first stage pre-digestion of corn stover was studied based on the following treatment variables: corn stover to liquid fraction of digestate (CS:LFD) ratio (1:7, 1:10, 1:13, 1:14), digestion temperature (55 °C, 60 °C) and digestion time (3, 7, 14 days). The reduction in lignin, cellulose and hemicellulose (LCH) was between 3.97% and 11.98%, which increased the biodegradability of corn stover. Corn stover pre-digested with a CS:LFD ratio of 1:10 at 55 °C for a period of 3 and 7 days was subjected to anaerobic co-digestion with cattle manure. The highest biomethane yield was observed on day 21 with a value of 357.41 mL/g volatile solids (VS) for untreated corn stover, 446.84 mL/g VS for corn stover pre-digested for 3 days and 518.58 mL/g VS for corn stover pre-digested for 7 days with LFD. The VS conversion efficiency for co-digestion of cattle manure with untreated corn stover, corn stover pre-digested for 3 days and 7 days was 42.8%, 43.3% and 51.8%, respectively, on day 21, which was higher than that (34.0%) of cattle manure only.

Performance, Microbial Community Analysis and Fertilizer Value of Anaerobic Co-digestion of Cattle Manure with Waste Kitchen Oil

Abstract. Co-digestion trials of beef cattle manure and waste kitchen oil (WKO) were conducted to evaluate potential increase of biogas production for a local beef farm anaerobic digester. The trials were conducted using laboratory-scale, semi-continuously loaded digesters under mesophilic conditions, with 21-day hydraulic retention time (HRT). In a preliminary test, WKO was added at 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume, each with replicate digesters (n=2), except for the 0% level, which had one digester (n=1). Methane (CH4) yield per week increased linearly with WKO levels. Populations of bacteriodetes decreased, while clostridiales and synergistales increased with the WKO levels. A second test was conducted using treatments with more replication: control (n=3), and 1.0% (n=3) and 2% (n=3) WKO levels. Methane yields of the 1.0% and 2.0% WKO levels were 79.1% and 203% higher than the control, respectively. Addition of WKO have resulted in changes of the metagenomics of the digesters. Populations of clostridiales increased, while bacteroidales and euryarchaeota methanomicrobia YC-E6 decreased with the WKO levels. The findings confirm adding low amounts (1% and 2%) of WKO as co-digestion feedstock can be an effective way to increase CH4 yield for beef operation anaerobic digestion, especially when there are available feedstock nearby. Keywords: Anaerobic digestion, Biogas, Methane, Semi-continuous digesters.

Mesophilic Anaerobic Co-digestion of Cattle Manure with Malus domestica and Dalbergia sissoo during Biomethane Potential Assays

Mesophilic Anaerobic Co-digestion of Cattle Manure with Malus domestica and Dalbergia sissoo during Biomethane Potential Assays

Mesophilic anaerobic co-digestion of cattle manure with Malus domestica and Dalbergia sissoo during biomethane potential assays

The burning of cattle manure for domestic use, and plant biomass left out in fields, is a common practice in South Asia, specifically Pakistan. According to the 2014 government of Pakistan (GOP) survey, Pakistan had 171 million head of cattle that would produce 345 billion kg of manure, which could easily be converted into 150 billion m3 of biogas. The focus of the present study was to evaluate the benefits from co-digestion of cattle manure (CM) with Dalbergia sissoo leaves (DSL) and Malus domestica leaves (MDL), with a focus on changes in the biodegradability, C/N ratio effect, and synergistic effect. The idea was to adjust the C/N ratio to increase biodegradability at mesophilic range to help the process to produce more methane than 100% manure-based digestion. First, the ideal pH and temperature conditions for mesophilic anaerobic digestion (AD) were optimized to carry out further co-digestion under the same conditions. The results of co-digestion revealed a 40% (251 NmL CH4/g VS) increase in methane yield by replacing 20% of volatile solid in CM-based AD reactors with MDL. This combination also presented a biodegradability of 59% and a synergistic effect (θ) value of 1.40, which corresponded to highly positive synergism reflecting the optimum growth conditions. The DSL/CM co-digestion also followed the same pattern, and the maximum methane yield of 229 NmL CH4/g VS was obtained using a 20/80 DSL/CM combination.

Comparison of Ultrasonic and Hydrothermal Cavitation Pretreatments of Cattle Manure Mixed with Straw Wheat on Fermentative Biogas Production

PurposePhysical pretreatment methods using ultrasound and hydrothermal cavitation were compared in the process of mesophilic anaerobic co-digestion of cattle manure mixed with straw wheat.MethodsTo evaluate the anaerobic biodegradability of pretreated lignocellulosic biomass, 20-days batch anaerobic digestion experiments were used.ResultsThe results showed that both methods achieved similar biomass solubilization (ca. 30% as CODsol), but in hydrothermal cavitation the pretreatment time was shorter and energy required was lower than in ultrasonic pretreatment. Solubilization of nitrogen compounds was higher in hydrothermal cavitation. Application of sonication with energy input of 4839 kJ/kg TS increased biogas production rate to 177 mL/mg VS·d, compared to 194 mL/mg VS·d with hydrothermal cavitation. However, biogas productivity was higher with ultrasound, where biogas enhancement ranged 59.6–64.2% in contrast to 35.6–39.4% hydrothermal cavitation. Both methods did not contribute to increase methane concentration in biogas.ConclusionsThe optimization of pretreatments for the production of biofuels from lignocellulosic residues is needed to be feasible at industrial scale. Physical pretreatment based on cavitation enhanced lignocellulosic biomass solubilization as well as biogas productivity, but the process yield was related to the cavitation equipment and mechanism.

Anaerobic co-digestion of cattle manure and meadow grass: Effect of serial configurations of continuous stirred tank reactors (CSTRs)

In this study, anaerobic co-digestion of cattle manure (CM) and meadow grass (MG) with serial configurations of continuous stirred tank reactors (CSTRs) was investigated. Four laboratory-scale CSTRs were operated at thermophilic condition (55 °C), of which two CSTRs were connected serially with equal working volumes while the remaining two CSTRs were operated as single CSTRs as controls. Improvements on bio-methane yield, methane contents and solids reduction were observed with serial CSTR configurations. The results showed that co-digestion with 5% (w/w) MG with serial configurations of CSTRs produced 24% more bio-methane compared with single reactor, with the total hydraulic retention time (HRT) being the same. The volatile fatty acids (VFA) concentration was found higher in the 1st reactor, but was reduced by 40–50% in the 2nd reactor. The improved bio-methane yield with serial CSTR configuration with 100% CM was 8%, indicating that the serial CSTRs process is superior in a co-digestion set up with addition of MG.

Mesophilic anaerobic co-digestion of cattle manure and corn stover with biological and chemical pretreatment

Biological and chemical pretreatment methods using liquid fraction of digestate (LFD), ammonia solution (AS), and NaOH were compared in the process of mesophilic anaerobic co-digestion of cattle manure and corn stover. The results showed that LFD pretreatment could achieve the same effect as the chemical pretreatment (AS, NaOH) at the performance of anaerobic digestion (AD). Compared with the untreated corn stover, the cumulative biomethane production (CBP) and the volatile solid (VS) removal rate of three pretreatment methods were increased by 25.40–30.12% and 14.48–16.84%, respectively, in the co-digestion of cattle manure and corn stover. T80 was 20–37.14% shorter than that of the control test (35±1days). LFD pretreatment not only achieved the same effect as chemical pretreatment, but also reduced T80 and improved buffer capacity of anaerobic digestion system. Therefore, this study provides meaningful insight for exploring efficient pretreatment strategy to stabilize and enhance AD performance for practical application.

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.