Anaerobic Digestion Of Cow Dung Research Articles

An Overview of Anaerobic Digestion of Cow Dung

In the past decade, governments and development agencies have contributed significantly to society through anaerobic digestion technology (ADT). Anaerobic digestion technology (ADT) has become an important tool in the fight against global poverty and environmental issues, leading to positive change in communities around the world. The technology works as a wet or dry process, depending on its classification. The process is complex and yields multiple benefits, such as creating a natural fertilizer that can be used to help crops grow, as well as generating renewable energy sources. It is common knowledge that many household-sized digesters installed in different areas are one-stage digesters. One-stage digesters do not require a separate pre-treatment stage before the digestion process. This makes them simpler and more cost-effective to install and operate than traditional two-stage digesters. Thus, some drawbacks are associated with these systems since they feed on just one type of feedstock. Many researchers fail to adequately address interactions critical to ADT’s operation, including interactions among growth factors and operating parameters. In a single-stage and one-substrate digester, researchers commonly neglect to study the digester feeding and operational conditions. Anaerobic digestion was the subject of this review, covering research conducted between 2001 and 2022. The study identified a significant drawback associated with mono-digestion and single-stage digestion. The findings illustrate that mono-substrate and single-stage digestion are worthwhile approaches, even though they have their challenges. However, adding a further digestion stage can significantly improve biogas production.

Riboflavin-loaded carbon cloth aids the anaerobic digestion of cow dung by promoting direct interspecies electron transfer

Cow dung generates globally due to increased beef and milk consumption, but its treatment efficiency remains low. Previous studies have shown that riboflavin-loaded conductive materials can improve anaerobic digestion through enhance direct interspecies electron transfer (DIET). However, its effect on the practical anaerobic digestion of cow dung remained unclear. In this study, carbon cloth loaded with riboflavin (carbon cloth-riboflavin) was added into an anaerobic digester treating cow dung. The carbon cloth-riboflavin reactor showed a better performance than other two reactors. The metagenomic analysis revealed that Methanothrix on the surface of the carbon cloth predominantly utilized the CO2 reduction for methane production, further enhanced after riboflavin addition, while Methanothrix in bulk sludge were using the acetate decarboxylation pathway. Furthermore, the carbon cloth-riboflavin enriched various major methanogenic pathways and activated a large number of enzymes associated with DIET. Riboflavin's presence altered the microbial communities and the abundance of functional genes relate to DIET, ultimately leading to a better performance of anaerobic digestion for cow dung.

Effect of organic loading on anaerobic digestion of cow dung: Methane production and kinetic study

Organic loading influences the effectiveness of producing biogas through anaerobic digestion. This study set out to investigate the effect of organic loading on the anaerobic mesophilic digestion of cow dung, the parameters involved in the digestion process and to evaluate the kinetics. Anaerobic digestion of cow dung at different organic loading (gVS/L) of 14 gVS/L, 18gVS/L, 22 gVS/L, 26 gVS/L and 30 gVS/L were investigated. Increasing the organic loading increased the methane yield of the cow dung. The highest cumulative methane yield was observed at 30 gVS/L with 63.42 mL CH4/gVS while the highest biogas yield was reported at 192.53 mL/gVS with the highest methane content of 89%. In addition, the modified Gompertz model equation with an R2 of 0.9980 demonstrated strong consistency and a good fit between predicted and experimental data. The high number of substrates added to the systems when increasing the organic loading increased the λ and slow down the nutrient transport and hydrolysis. This study provides current information on the effects of organic loading on the anaerobic digestion of cow dung in batch mode, including experimental conditions and operational parameters.

CO2 AND H2S REMOVAL FROM BIOGAS BY USING FOUR MEMBRAN OF INTEREST

Biogas upgrading in Africa remains a huge challenge for producers of small installations due to the high cost of acquisition of all-in-one installations designed and used in developed countries. This study brings a clear idea on some purification methods accessible to these small producers while proposing those optimal for decarbonation and desulphurization of biogas. Starting from the analysis over time of the biogas resulting from the anaerobic digestion of cow dung, the system of NaOH filters and steel wool mounted in series is the one proposed for optimality (with purification capacities respective CO2 of the order of 95.9063 ± 0.0864 % and H2S of 100 %). Better still, the use of a steel wool filter in series with activated carbon (based on coconut shells or bamboo) makes it possible to increase the desulfurization capacity of the latter up to 100 %.

Comparative performance evaluation of a porous radiant burner with a conventional burner: Biogas combustion

• Crude biogas combustion between novel SFPRB and CB has been investigated. • Heat transfer enhancement is achieved via two-layer porous ceramic (SiC and Al 2 O 3 ) • SFPRB can operate on lean combustion, while CB functions in rich fuel condition. • SFPRB offers maximum energy saving of 38% and reduction of CO by 95% and NO x by 85% The aim of present research is to conduct a comparative performance analysis of a newly developed Sideway Faced Porous Radiant Burner (SFPRB), with a commercially available Conventional Burner (CB). Both the burners have been fuelled by crude biogas. Comparative study of both the burners have been done in terms of thermal and combustion efficiencies and pollutant emissions. The SFPRB is composed of Alumina (Al 2 O 3 ) and Silicon Carbide (SiC) porous matrices. Biogas generated from anaerobic digestion of cow dung, consisting majorly of 43-56% methane (CH 4 ) and 34-38% carbon dioxide (CO 2 ), was used as fuel during investigation. Combustion in SFPRB was found to be stable in the equivalence ratio range of 0.75-0.97, while CB works in rich fuel condition at an equivalence ratio of 1.38. In order to get an insight in to the combustion behaviour of SFPRB, temperatures in both axial and radial directions have been measured. The performance comparison of SFPRB with CB have been done within the firing rates of 442-884 kW/m 2 . Maximum percentage improvement in thermal efficiency of ∼38% is achieved with SFPRB. The measured emission values from SFPRB have been always lower than CB. The SFPRB emitted maximum CO and NOx 165 ppm and 8.2 ppm respectively; while CB emitted higher values 3276 ppm and 27 ppm respectively. The present experimental investigation confirmed that SFPRB delivered superior performance at all test cases. The findings from the present research work provides an insight into the development of an energy efficient and clean burner for crude biogas application.

Enrichment culture combined with microbial electrochemical enhanced low-temperature anaerobic digestion of cow dung

Enrichment culture combined with the microbial electrochemical system was used to co-enhance the low-temperature (20 °C) anaerobic digestion. The results showed that enrichment culture combined with microbial electrochemical system increased the cumulative methane production in low-temperature anaerobic digestion system by 39.64 % and 133.29 % compared to single and no enrichment culture, respectively. Enrichment culture combined with microbial electrochemical system increased the relative abundance of methanogenic archaea (Methanomassiliicoccus, Methanocorpusculum, unclassified Methanomicrobiaceae, Methanobacterium, Methanoculleus, Methanocalculus) and the relative abundance of cold-tolerant hydrolytic acidifying bacteria (unclassified Bacteroidetes, Treponema). The expressions of specific enzyme genes in the methanogenesis pathway were enhanced, including acetyl-CoA synthetase, formylmethanofuran dehydrogenase, methanol cobalamin methyltransferase, etc. These results indicated that enrichment culture combined with microbial electrochemical system enhanced low-temperature anaerobic digestion methanogenesis by altering microbial communities and stimulating enzyme gene expression to affect volatile fatty acids, pH, redox potential, and reducing sugar parameters.

Deployment of treated and compressed biogas as a sustainable fuel for ceramic kiln firing

Inefficiency, emission of greenhouses gases and the deleterious effects of carbonaceous fuels on both human health and the environment are responsible for the increased in exploration and adoption of eco-friendly and sustainable fuels to various aspects of human development and production processes. This study was aimed at the generation, treatment and compressing of biogas into Liquefied Petroleum Gas Cylinder (LPGC) for deployment to firing ceramic kiln. The methodology involved the anaerobic digestion of cow dung and the treatment of the generated gas using water scrubbing technology. The results of the study showed an increased in methane content from an untreated value of 43.5% to 93.98%, the elimination of CO2, and H2S; reduction in volume of gas used in firing a ceramic kiln to 1030 °C from 22,300 L of untreated biogas to 492 L of treated biogas, as well as the prevention of 108,000 g of methane, 124,00 g of CO2, 74,400 g of CO and 173.6 g of NO2 from venting into the climate system.

Using soap waste from biodiesel production to intensify biogas generation during anaerobic digestion of cow dung

The aim of the work is to increase the yield of biogas and the generation of electricity at biogas plants due to the joint fermentation of cattle manure with the addition of soap stock obtained from soap waste from biodiesel production. To achieve this goal, the following tasks were solved: the yield of biogas from cattle manure was determined with the addition of soap stock for a periodic mode of loading the substrate, taking into account the data obtained, a mathematical model of biogas output for a quasi-continuous mode of loading the substrate into the digester was developed and its adequacy was confirmed. The novelty of the work lies in the fact that according to the data of experimental studies of biogas yield at a periodic loading mode using this model, it is possible to predict the maximum biogas yield for a quasi-continuous mode of loading the digester. The significance of the research results lies in the fact that when soap stock is added to the substrate with a periodic mode of loading the digester, a general increase in the biogas yield without diauxy is observed by about 2 times. The optimal content of soap stock in the substrate for a quasi-continuous mode of loading the digester, at which the biogas yield will be maximum, is 1.32%. When electricity is sold at a feed-in tariff, the payback period of a biogas plant is reduced from 8.7 years to 5.0 years.

Cobalt nanoparticles to enhance anaerobic digestion of cow dung: focusing on kinetic models for biogas yield and effluent utilization

The impacts of Co nanoparticles (NPs) on the anaerobic digestion (AD) of cow dung were investigated using kinetic models (modified Gompertze, logistic, and first-order) and experimental measurements. The deviation between the predicted and measured data for biogas yield with modified Gompertze and logistic models were 0.66–2.26% and 1.43–4.19%, respectively. The addition of Co NPs (1–3 mg/L) improved the hydrolysis rate (K) value by 66.66–144% compared with the control. Furthermore, the fertilizer efficiency of effluent with Co NPs was comparable to that of commercial NPK compound fertilizer. The combination of kinetic models and experimental measurements can effectively quantify the impact of Co NPs on AD performance and provide an informed choice for industrial production.

Upgrading biogas using Eburru zeolitic rocks and other adsorbent materials to remove carbon dioxide and hydrogen sulphide

The trace amounts of carbon dioxide and hydrogen sulfide in raw biogas lower its calorific value,cause corrosion and make it hard to compress biogas into the cylinder. Raw biogas was obtainedfrom anaerobic digestion of cow dung and market wastes. The gas was stored in tubes or urine bagbefore upgrading. Natural zeolite rocks, maize cobs, steel wire, desulphurizer, and worn-out tyreswere used as the upgrade materials. The composition of biogas was recorded before and afterupgrading using a GP180 portable biogas analyzer from Henan, China. The measured level of rawbiogas was 0.0227% H2S, >20% CO2 and 52-56% CH4. The most efficient upgrade materials werezeolite rocks with upgrade levels of 89–93% methane. The total removal using zeolite wasobserved to be 75% CO2 and 95.34% H2S. The morphological structures of zeolitic rocks accountfor its higher upgrading properties compared to other materials. In addition, the porosity in theserocks mean that CO2 and H2S were adsorbed resulting in high CH4 levels in the upgraded biogas.Other adsorbents showed upgrading properties with removal rates above 70% for both H2S andCO2.
 Keywords: Biogas, Upgrading, Natural zeolite, Bio-methane

Characterization of Biogas Digestate for Solid Biofuel Production in Uganda

In this study, suitability of digestate from anaerobic digestion of cow dung, pig dung, and human waste feedstock as a solid fuel for thermal applications was investigated. The digestate was obtained at different retention times from laboratory scale and household digesters and later characterized. Carbonized briquettes were produced from the digestate followed by their physico-chemical characterization and assessment for combustion and mechanical properties. Results of the proximate analysis of the digestate were: moisture content (6.1 to 18.3%), volatile matter (27.9 to 47.7%), ash (15.0 to 48.9%), and fixed carbon (9.1 to 17.1%). The ultimate analysis results for the digestate were: carbon (19.5%), hydrogen (3.3%), oxygen (20.8%), and nitrogen (7.0%). The developed briquettes showed a moisture content, volatile matter, ash, and fixed carbon in the range of 3.7 to 8.9%, 9.9 to 21.5%, 45.6 to 76.4%, and 8.2 to 22.8%, respectively. Their ultimate analysis results were: carbon (21.1%), hydrogen (1.3%), oxygen (1.8%), and nitrogen (1.9%). The briquette combustion properties revealed an ignition time, burning rate, and water boiling time of 5.35 seconds, 0.16 g/min, 31.1 minutes, respectively with higher and lower heating values of 14.87 and 7.88 MJ/kg, respectively. The briquette ash compounds were sodium 1718.5 ppm, potassium 20017.8 ppm, copper 6.12 ppm, cadmium 1.22 ppm, and lead 25.6 ppm. TGA/ DTG analysis indicated high mass loss rates at 105°C and maximum energy release between 600 and 900°C. The mechanical compressive strength was between 19 and 50 MPa, with bulk density between 1.82 and 2.02 g/cm3. Thus, the briquettes from the biogas digestate demonstrate potential for domestic thermal applications in Uganda.

Characterization and Application of Eburru Zeolite Rocksin Upgrading Biogas to Bio-Methane

The trace amount of carbon dioxide and hydrogen sulphide in raw biogas lowers its calorific value, causes corrosion and makes it hard to compress the biogas into cylinders. Raw biogas was obtained from anaerobic digestion of cow dung and market wastes. The gas was stored in tubes or urine bags before upgrading process. Eburru natural zeolite rocks were used as the upgrade materials. The measured initial level of raw biogas was 0.0227% H2S, > 20% CO2 and 52-56% CH4. The total removal using zeolite was observed to be 75% CO2 and 95.34% H2S leading to 83.45 – 91.23% methane levels. The morphological structure of zeolitic rocks accounted for its higher upgrading properties. In addition, the porosity in these rocks meant that CO2 and H2S were adsorbed resulting in higher CH4 levels in the upgraded biogas.

Optimization of Reactor Temperature for Continuous Anaerobic Digestion of Cow Manure: Bangladesh Perspective

Converting organic waste into energy through anaerobic digestion is gaining popularity day by day. The reactor temperature is considered as one of the most vital factors for the digestion process. An experiment was conducted in the Biogas Laboratory of Green Energy Knowledge Hub at Bangladesh Agricultural University (BAU) to examine the influence of temperature on anaerobic digestion of cow-dung. Laboratory-scale continuous stirred tank reactors with a working volume of 15 L were operated for a 30-day retention time. The reactors were set at 20 °C, 25 °C, 30 °C, 35 °C, 40 °C and 45 °C, respectively to determine the effect of temperature on anaerobic digestion performance. Different parameters like total solids, volatile solids, pH, volatile fatty acids, ammonia nitrogen, total nitrogen, biogas production rate and methane concentration were examined. Among all the reactors, the reactor at 40 °C temperature produced maximum biogas (312.43 L/kg VS) and methane yields (209.70 L/kg VS), followed by the reactors at 35 °C and 30 °C, respectively. Statistical analysis of the obtained experimental results using Minitab® showed that the optimum process performance in terms of methane yield and volatile solid degradation is achieved at a reactor temperature of 35.82 °C.

Evaluation of Main Parameter Process of Anaerobic Digestion of Cow Dung in Fixed Dome Biodigester on Methane Gas Quality

Methane gas produced from anaerobic digestion has been widely studied through some of the researches, but the quality of methane gas produced is still a problem because the concentration of methane gas produced is generally low. Biogas formation is a complex process involving several process parameters that must be controlled such as temperature, pH, and fermentation time. Therefore the use of biogas is still problems and it has not been widely used. This study aimed to evaluate the main parameter process of anaerobic digestion of cow dung in fixed dome biodigester on methane gas quality. The research was carried out for 30 days and every 5 days the quality of methane gas (CH4), organic content (COD) and total solids (TSS) were analyzed. From the results of the study, it was found that temperature, pH, and fermentation time greatly effect on biogas produced. at high methane gas concentrations (59,12%) occur at pH 7.1, temperatures 350 C and fermentation time of 25 days. Besides that the longer the fermentation time, the COD and TSS content decreases and the concentration of methane gas increases.

Anaerobic digestion of textile industries wastes for biogas production

Energy and nutrient recovery by anaerobic digestion of textile industry wastes (sludge) is facing challenges due to the anticipated toxicity, lower pH (6.6) and low C:N ratio (12.2). In the present study, the anaerobic co-digestion of textile aerobic sludge (ETP) generated in industry with different co-substrates (Food waste and Cow dung) was assessed through biochemical methane potential tests under mesophilic temperature (35 °C). The VS and ash content of textile sludge was observed to be 5.9 gVS/L and 41.4 g/L, respectively. In lab-scale study, the cumulative biogas and methane production from textile sludge was observed under controlled conditions (36 ± 1 °C) using CD (cow dung) as co-substrate in 1:1 ratio. It was found that the cumulative biogas and methane production were 567.3 and 244.1 mL/gVS added, respectively, during the 30-day digestion period while using the CD with textile sludge. On-site (at leading textile industry) cumulative biogas production from textile sludge with CD and FW (food waste) co-substrate was 524.4 and 288.3 mL/gTS added, respectively, during the 30-day anaerobic digestion. In the lab-scale study, the VSR (volatile solid reduction), Total Alkalinity (T. Alk.) and TVFA (Total volatile fatty acid) observed were 39.5%, 300 and 340.7 mg/L after completion of anaerobic digestion. The digestibility of the textile sludge, as reflected based on COD (chemical oxygen demand) removal, was higher with CD co-substrate (51%) as compared to FW (37%). After anaerobic digestion of CD and FW co-substrate, the TAN (Total ammoniacal nitrogen) and T. Alk. were observed as 147.5, 222.5 and 2560, 2800 mg/L, respectively. The present study provided an efficient method for textile sludge utilization coupled with biogas generation. The surplus energy generated during the process can be utilized in several operational units and also overcome the sludge disposal issued faced by leading textile industries.

Metagenomic insights into the microbial community and biogas production pattern during anaerobic digestion of cow dung and mixed food waste

AbstractBACKGROUNDThe uncontrolled overproduction of fruit and vegetable waste causes serious environmental challenges such as emission of greenhouse gases. Anaerobic digestion (AD) is becoming a widely adopted technology for treatment of food waste with the concomitant production of biogas. This study investigated the link between microbial community structure and biogas production when using cow dung and mixed fruit and vegetable waste (MFVW) as substrates.RESULTSSemi‐continuous stir tank reactors were used for AD of cow dung and MFVW over a period of 40 days. The highest accumulative methane yield (112.9 L) was obtained from co‐ digestion, intermediate yield (59.5 L) was obtained from cow dung and lowest yield (6.1 L) from MFVW at the end of the digestion experiment. Polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) revealed higher bacterial and archaeal diversity indices in co‐digestion in comparison to mono‐digestion of cow dung and MFVW. High‐throughput sequence analyses showed that operational taxonomic units (OTUs) belonging to the phyla Bacteroidetes, followed by Firmicutes, Actinobacteria and Proteobacteria were dominant in all treatments.CONCLUSIONThe results of the study demonstrated that the enhanced methane production in co‐digestion could be attributed to the neutral pH and partial shift of archaea from Methanosaeta to Methanosarcina rich communities. © 2019 Society of Chemical Industry

Laser Improves Biogas Production by Anaerobic Digestion of Cow Dung

This study investigates the digestion of cow dung (CD) for biogas production at laboratory scales. The study was carried out through anaerobic fermentation using cow dung as substrate. The digester was operated at ambient temperatures of 39.5 °C for a period of 10 days. The effect of iron powder in controlling the production of hydrogen sulfide (H2S) has been tested. The optimum concentration of iron powder was 4g/L with the highest biogas production. A Q – swatch Nd:YAG laser has been used to mix and homogenize the components of one of the six digesters and accelerate digestion. At the end of digestion, all digestions effluent was subjected to 5 laser pulses with 250mJ/pules to dispose waste biomass.

Potential of wastewater treating Chlorella minutissima for methane enrichment and CO2 sequestration of biogas and producing lipids

An algal biorefinery approach is today's need for commercialization of microalgal biodiesel production. In the present study, an indoor photobioreactor with Chlorella minutissima was evaluated to upgrade biogas produced from anaerobic digestion of cow dung. The potential of C. minutissima was assessed in two different growth media viz. BG 11 and wastewater. The significant CO2 absorption reported by C. minutissima was in the range of 75–85.4% at 1296 μmol m−2s−1 of light intensity and 0.33 vol per volume per minute (vvm) gas flows. The present study demonstrated that there is an increase in methane content from 63.5 to 86.4% in the effluent biogas. The highest biomass productivity was observed at 1296 μmol m−2 s−1 light intensity with the same gas flow and the productivity of 0.18 gL−1 and 2.2 gL−1 in the BG11 medium and wastewater respectively. Further, we reported that total lipid content based on dry biomass of C. minutissima were 22.4% and 26% in the BG11 medium and wastewater, respectively. The gross calorific value of treated biogas was also higher (8.15 kWh m−3 and 8.63 kWh m−3) in both BG11 and wastewater, respectively.

Laser Improves Biogas Production by Anaerobic Digestion of Cow Dung

This study investigates the digestion of cow dung (CD) for biogas production at laboratory scales. The study was carried out through anaerobic fermentation using cow dung as substrate. The digester was operated at ambient temperatures of 39.5 °C for a period of 10 days. The effect of iron powder in controlling the production of hydrogen sulfide (H2S) has been tested. The optimum concentration of iron powder was 4g/L with the highest biogas production. A Q – swatch Nd:YAG laser has been used to mix and homogenize the components of one of the six digesters and accelerate digestion. At the end of digestion, all digestions effluent was subjected to 5 laser pulses with 250mJ/pules to dispose waste biomass.

Co-digestion of rice straw and cow dung to supply cooking fuel and fertilizers in rural India: Impact on human health, resource flows and climate change

Anaerobic digestion of cow dung with new feedstock such as crop residues to increase the biogas potential is an option to help overcoming several issues faced by India. Anaerobic digestion provides biogas that can replace biomass cooking fuels and reduce indoor air pollution. It also provides digestate, a fertilizer that can contribute to compensate nutrient shortage on agricultural land. Moreover, it avoids the burning of rice straw in the fields which contributes to air pollution in India and climate change globally. Not only the technical and economical feasibility but also the environmental sustainability of such systems needs to be assessed. The potential effects of implementing community digesters co-digesting cow dung and rice straw on carbon and nutrients flows, human health, resource efficiency and climate change are analyzed by conducting a Substance Flow Analysis and a Life Cycle Assessment. The implementation of the technology is considered at the level of the state of Chhattisgarh. Implementing this scenario reduces the dependency of the rural community to nitrogen and phosphorus from synthetic fertilizers only by 0.1 and 1.6%, respectively, but the dependency of farmers to potassium from synthetic fertilizers by 31%. The prospective scenario returns more organic carbon to agricultural land and thus has a potential positive effect on soil quality. The implementation of the prospective scenario can reduce the health impact of the local population by 48%, increase the resource efficiency of the system by 60% and lower the impact on climate change by 13%. This study highlights the large potential of anaerobic digestion to overcome the aforementioned issues faced by India. It demonstrates the need to couple local and global assessments and to conduct analyses at the substance level to assess the sustainability of such systems.