Waste Biogas Production Research Articles

Biogas Potential Assessment of Co-digestion of Various Wastes (Cassava Residues, Poultry Droppings and Household Waste) in the Gbêkê Region, Bouaké, Central Ivory Coast

Assessing the potential for biogas from cassava residues, poultry droppings and household waste in Bouaké will help determine the viability of a sustainable energy project. Cassava is abundant in this region, and its exploitation produces starch-rich residues, a potential source of biogas through anaerobic digestion. Poultry droppings from livestock farming and household waste are respectively sources of biomass rich in nitrogen and various organic materials. Unfortunately, poor management of these wastes leads to environmental problems, including foul odors that encourage disease, and soil and groundwater pollution. It is therefore necessary to quantify this waste with a view to transforming it into renewable energy. To do this, we began by collecting cassava residues and household waste from attiéké production cooperatives and some restaurants, and poultry droppings from city farms. After collection, we sorted and mixed the different types of waste with water, then filled the digesters. And finally, we made different formulations from these wastes for biogas production. During the process, the results obtained from the physico-chemical characteristics of the waste give respectively for pH 6.4 and 7.4, for BOD5 25 442 mg/L and 19 475 mg/L, for COD 74 400 mg/L and 62 100 mg/L, for MES 3 733 mg/L and 2 675 mg/L, for MS 11.6% and 8.1%, for VDM 64.3% and 58.2%. Concerning biogas composition and production, methane is estimated at 56.5% on average, with a standard deviation of 6.1, giving a biogas volume of 3.2 m3. These results provide valuable indications for the planning and development of biogas production facilities in Bouaké. They encourage the adoption of renewable energies, waste reduction and better management of organic residues, thus contributing to the environmental and economic sustainability of the region.

Characterization and analysis of fish waste as feedstock for biogas production

Abstract Fish waste (FW) is biodegradable waste that remains underutilized and causes a problem to the environment since the existing disposal techniques result in health risks and environmental pollution. FW has significant potential for producing biogas that decreases the reliance on fossil fuels because it contains easily biodegradable organic matter. The physicochemical analysis of the FW such as moisture content of 61.78%, volatile solids (VS) of 93.94%, total solids of 38.21%, ash content (AC) of 0.52%, total organic carbon of 54.2%, total Kjeldahl nitrogen of 9.2% and carbon to nitrogen (C/N) ratio of 5.89% were considered and analyzed in this research. In addition, the methane potential was determined and obtained using gas detector. The results shown that the methane (CH4) content in FW was 50.12%, which was the potential feedstock of FW for biogas production. Nevertheless, the VS of FW was high, which was good for this feedstock to be easily digested as the sign of producing biogas and demonstrates 99.9985% of performance rate. Finally, the FW had a lower C/N ratio compared with other biogas production waste. Future work needs to consider co-digestion with higher C/N ratio feedstocks.

Microbial Pretreatment of Chicken Feather and Its Co-digestion With Rice Husk and Green Grocery Waste for Enhanced Biogas Production.

To utilize wastes and residues sustainably and excellently, there is a need to fend for efficient methods and resources for biogas production. Use of poultry waste for biogas production represents one of the most important routes toward reaching global renewable energy targets. The current study involves microbial pretreatment of chicken feather waste, followed by its co-digestion with rice husk and green grocery waste in batch and continuous reactors, respectively. Microbial pretreatment of chicken feathers by keratinase secreting Pseudomonas aeruginosa was an effective and eco-friendly approach to make its recalcitrant structure available as a raw substrate for biogas production. The current study also addressed the enhancement and stability of anaerobic digestion by co-digestion. Results demonstrated that biogas production was increased by microbial pretreatment of chicken feathers and that the percentage increase in biogas yield was 1.1% in microbialy pretreated feathers compared to mono-digestion (non-pretreated feathers) in batch fermentation. The highest yield of biogas was obtained in a batch reactor having co-digestion of pretreated rice husk and microbial pretreated chicken feathers. The co-digestion of chicken feathers hydrolysate with green grocery waste in continuous fermentation mode has also enhanced the biogas yield as compared to average of mono-digestion (chicken feather hydrolysate and green grocery waste) and, therefore, improve the efficiency of the overall process.

Optimization of Hydraulic Retention Time and Organic Loading Rate in Anaerobic Digestion of Squeezed Pineapple Liquid Wastes for Biogas Production

Pineapple wastes are produced in huge amount during the industrial canning process of pineapple; in Thailand over 400,000 tons per annum of canned pineapple exported leaving behind the waste. Besides the pulps and peels as solid wastes, the squeezed pineapple liquid wastes (SPLW) extracted from solid wastes can also be used for anaerobic digestion. In the present study, the anaerobic digestion of liquid squeezed from industrial pineapple peels was carried out using a lab-scale hybrid reactor. The reactor was operated for over 170 days with the hydraulic retention time (HRT) of 20 days decreasing down to 5 days and simultaneous control of organic loading rate (OLR). Under controlled conditions in the hybrid reactor, pH was maintained at 6.5–7.6 by adding alkaline for anaerobic microbial activity. Results showed that the chemical oxygen demand (COD) removal efficiency was at ≥ 90% for all conditions. The biogas production (mL/day) increased thoroughly from longer HRT to shorter HRT, as same as methane production with the maximum values (HRT 5 days, OLR 5 g/COD/ day with recirculation) of 55,130 and 30,322 mL/day, respectively. Moreover, the highest yields of biogas and methane were also investigated under similar conditions with the values of 0.504 and 0.277 L/gCOD, respectively. Interestingly, this optimization of both HRT and OLR of lab-scale anaerobic digestion process could be further practically applied to pilot or industrial scale in canned pineapple factories for biogas production.

Biogas Production in Laboratory Scale from Different Organic Wastes Using Primary Sludge as Co-substrate

Biogas production technology not only constitutes a biofuel source, but also can be a mitigation measure for the various environmental pollutants. This technology, i.e., anaerobic digestion is a biological process that takes place naturally when microorganisms break down organic matter in the absence of oxygen. In an enclosed chamber, controlled anaerobic digestion of organic matter produces biogas which is predominantly methane. The produced methane then can be directly used; or after certain conditioning, can be used in onsite power generation, heating homes or as vehicular fuel. Besides, organic waste is increasingly becoming a major problem in every society imposing serious economic and environmental concerns. For this reason, many contemporary researches are emphasizing in finding sustainable solutions to recycle and produce energy from such waste. In this context, this paper aims to investigate the potential of cow and chicken manure, and olive waste for biogas production obtained through the anaerobic digestion process.
 The substrates were placed in laboratory scale digesters without pretreatment. The retention time in the digesters was 30 days. The samples of the tested substrates were collected and analyzed for pH, total solids, ash, and the content of volatile solids (VS). Under mesophilic conditions, all combinations of cow and chicken manure, and olive waste with sludge by an anaerobic pond of a trickling filter treatment plant, as co-substrate, significantly improved biogas, and methane yields. The experimental results showed that chicken manure (CM) is the most suitable for anaerobic digestion (AD).
 The next step of the study will consist in implementing a large scale of biogas production plants and we will estimate the national potential of green energy produced by this technology and map the areas that need digesters.

Viability of Food Waste to Biogas Energy Through Anaerobic Digestion

This study was conducted on the feasibility of food waste for biogas production in Wolaita Sodo University, Ethiopia. The study aimed to investigate the potential of different food waste categories for biogas production through anaerobic digestion. A total of 40 representative food waste samples with 100 grams each were collected from four source-separated food waste categories based on the various food menus of the University. The collected food waste samples were tested for %TS, %TN, %TVS and %TC. Besides, laboratory-scale anaerobic digestions were carried out exhaustively for each food sample for 25 days at 35 o C. Thus, the proportion of CH 4 and CO 2 of the biogas produced from each food waste categories was also evaluated. The analysis was done using IBM SPSS Statistics 21. Results showed that %TN, %TS, %TVS and %TC were 1.62%, 30.75%, 29.29 % and 16.27%, respectively. Small C: N ratio (10:1) was scored. The ratio of VS: TS was very high (95%). The mean CH 4 proportion produced from ISV, RB, IML and MA were 61, 65, 63 and 63 respectively. However, the mean CO 2 proportion produced from ISV, RB, IML and MA were 22, 20.5, 15.5 and 16 respectively. Thus, the proportion of CH 4 produced 61-65% and high ratio of VS: TS showed the viability of all food waste categories to biogas energy production. However, the small C: N ratio which is an indicator for the resistance of anaerobic digestion implied in need of other organic wastes rich in carbon content to the reactor. In general, the food wastes generated from WSU students’ cafeteria are a promising feedstock for anaerobic digesters concerning biogas production. Keywords: Food waste , Anaerobic digestion, C: N ratio, %CH 4 , % CO 2 and Biogas DOI: 10.7176/JETP/10-4-01 Publication date: August 31 st 2020

Life cycle assessment (LCA) of end‐of‐life dairy products (EoL‐DPs) valorization via anaerobic co‐digestion with agro‐industrial wastes for biogas production

AbstractBACKGROUNDThe aim of the present study was to assess the environmental impacts of end‐of‐life dairy products (EoL‐DPs) management via their co‐treatment with agro‐industrial wastes (AgW) in a centralized biogas facility located in Cyprus using a gate‐to‐gate life cycle assessment (LCA) approach. Two different scenarios were examined under the framework of this project. In the first one, co‐treatment of EoL‐DPs with various AgW in a 20:80 (w/w) ratio was evaluated in a one‐stage mesophilic anaerobic digestion (AD) process. In the second scenario, the same amount of EoL‐DPs were acidified before methanogenesis with AgW in order to improve biogas production.RESULTSPrior acidification of EoL‐DPs showed a better environmental performance compared with the results obtained upon direct co‐digestion in a mesophilic digester, having a total impact of 52.44 Pt against 57.13 Pt respectively. Biogas production upon acidification, and therefore energy yield, was higher, reaching up to 22.88 m3 CH4 ton−1 feed (229.25 kWh ton−1 feed), compared with 17.45 m3 CH4 ton−1 feed (174.85 kWh ton−1 feed) for the case where no pretreatment was performed.CONCLUSIONThe acidification of EoL‐DPs enhanced the environmental performance of the process by reducing its impact by 8.2% (in Pt equivalents). The energy consumption of the biogas plant mixing equipment was identified as the process hotspot. However, further analysis of the environmental performance of the proposed process is required by extending the system's boundaries towards a cradle‐to‐grave approach. © 2019 Society of Chemical Industry

One- and two-stage anaerobic co-digestion of cucumber waste and sewage sludge

ABSTRACT The demand for uniformly sized and shaped produce that are aesthetically pleasing results in significant food waste throughout the world. Cucumber waste is a major agricultural waste product in a number of countries, especially areas with high pickle production. Opportunity exists for wastewater treatment plants containing anaerobic digesters to utilize cucumber agricultural and industrial waste for biogas production. The biomethane potential of cucumber waste as a substrate for co-digestion with sewage sludge was assessed. The impact of long-term co-digestion of cucumber was then evaluated using mesophilic continuously stirred tank reactors (CSTRs), in both single- and two-stage anaerobic co-digestion with sewage sludge. Ground cucumber waste was added to sewage sludge at 8% of the volume (4.5–4.6% of the organic load) and CSTRs were maintained for five hydraulic retention times (HRTs). One-stage co-digestion of cucumber waste produced comparable gas levels as CSTRs without cucumbers (averaging 219 and 221 m3/kgVS/h, respectively) after two HRTs. The two-stage cucumber co-digestion CSTR averaged 64% higher specific gas than the control and single-stage digester, although the volumetric gas produced was lower (averaging 152 m3/kgVS/h) likely due to gas loss in the first stage resulting in a lower organic load rate. After four HRTs, relative methanogen content showed dramatic differences in levels of hydrogenotrophic methanogens for the two-stage digester, while the one-stage digester containing cucumber waste showed minor differences relative to the control. Cucumber waste co-digestion with sewage sludge is effective although numerous conditions could be utilized to optimize gas production.

Isolation of Microorganisms Associated with Biodegradation of Household Domestic Wastes for Biogas Production in Niger State, Nigeria

This study focused on the isolation of microorganisms associated with biodegradation of domestic wastes in three rural communities (Gbadagbadzu (A), Ndawangwa (B), and Kuchiworo (C)) in Lavun Local Government Area of Niger State, Nigeria, for biogas production. The biogas was produced by anaerobic microbial degradation of different biodegradable household domestic waste aided by fresh rumen of cow. The anaerobic microbial degradation was carried out in a temperature range of 250C to 320C for a detention time of 39 days for rural biogas production. The results showed the presence of the following bacteria: Bacillus cereus, Sphingobacterium yamdrokense, Clostridium perfringens, Salmonella typhi, Alkaligenes faecalis, Pseudomonas aeruginosa, Staphylococcus epidermidis, Klebsiella pneumoniae and Bacillus licheniformis while fungi isolated were Muccor pusillus and Aspergillus flavus. The research therefore shows that household domestic wastes have the potential to produce biogas with or without the addition of inoculum.

Evaluation and influence of composts and their organic matter on the growth of spring barley

Pot trial experiments were conducted with the aim of determining organic matter composition and the influence on the growth of spring barley of different types of composts. The plants were grown in 6 l vegetative pots on the experimental site of the LRCAF Agrochemical Research Laboratory. Compost with soil were mixed by the following volume – 10, 20, 30 and 40%. Spring barley was grown for two years – in 2015 and 2016. This experiment investigated green waste and food waste, sewage sludge and biogas production waste. The largest amounts of organic matter, organic and total carbon, and total nitrogen were found in the biogas production waste compost. The minimum contents of organic matter and other nutrients were estimated in the green waste compost. The following biometric measurements on spring barley were taken: plant height, 1 000 grain weight and grain yield. The best growth of barley was in the substrate with biogas production waste in 2015 – plant height 43.7–53.7 cm, 1 000 grain weight 45.6–49.2 g, grain yield per pot 19.1–23.0 g, and the minimum contents were in the green waste substrate. In 2016, the best results were obtained in the substrates with green and food waste compost. The nitrogen content was determined in spring barley grain and straw. In 2015, the total nitrogen content in plant grains and straw was increased by the substrate of biogas production waste, and in 2016 it was increased by the substrate of food waste, sewage sludge and biogas production waste.

Using agricultural waste for biogas production as a sustainable energy supply for developing countries

The paper focuses on the research, development, and application of simple, reliable, efficient, and low maintenance technology for the production of biogas from local organic agricultural wastes in the Republic of Togo. This technology is intended as a sustainable decentralised energy supply, which should meet the economic and social conditions of developing countries in the West African region. The paper briefly outlines the current state of small-scale biogas production in Africa. Several reviews of the already existing and operated facilities in the mentioned area are named and evaluated. Specific opportunities, limitations, and experience are discussed and the results of the biogas production studies using pineapple waste, carried out at Augsburg University of Applied Sciences and at Brno University of Technology, are presented.

Characterizing Bacterial Consortia from an Anaerobic Digester Treating Organic Waste for Biogas Production

Characterizing Bacterial Consortia from an Anaerobic Digester Treating Organic Waste for Biogas Production

Effect of mild-temperature H 2O 2 oxidation on solubilization and anaerobic digestion of waste activated sludge

Efficient sludge management is among the most challenging issues in wastewater treatment today, and anaerobic digestion is regarded as a viable solution. Mild-temperature H 2O 2 oxidation was examined for enhanced solubilization and biogas production of waste activated sludge (WAS). The effects of pretreatment factors (i.e. temperature and H 2O 2 concentration) on the degree of WAS disintegration (DD) and biogas yield (BY) were assessed by response surface analysis within the design space of 60–90°C and 0–200 mM H 2O 2. Significant sludge disintegration (up to 23.0% DD) and visibly enhanced BY (up to 26.9%) were shown in the pretreatment trials. Two response surface models to describe how DD and BY respond to changes in the pretreatment conditions were successfully constructed (R2>0.95, p<0.05). The models showed totally different response surface shapes, indicating the DD and BY were influenced by pretreatment conditions in very different ways. DD was dominantly affected by temperature and showed higher model responses at the high-temperature region, while the BY response peaked in the low-temperature and mid-level H 2O 2 region. This observation implies that the enhanced solubilization of WAS was not directly translated into an increase in biogas production. Our results showed that WAS can be efficiently disintegrated by H 2O 2 oxidation under mild-temperature conditions for enhanced anaerobic digestibility. Within the explored region of pretreatment conditions, the maximum BY was estimated to be 82.1 mL/gCODadded (32.8% greater than the untreated control) at (60.0°C, 74.2 mM H 2O 2).

Impact of pretreatment on solid state anaerobic digestion of yard waste for biogas production

Solid state anaerobic digestion, as a safe and environment-friendly technology to dispose municipal solid wastes, can produce methane and reduce the volume of wastes. In order to raise the digestion efficiency, this study investigated the pretreatment of yard waste by thermal or chemical method to break down the complex lignocellulosic structure. The composition and structure of pretreated yard waste were analyzed and characterized. The results showed that the pretreatment decreased the content of cellulose and hemicelluloses in yard waste and in turn improved the hydrolysis and methanogenic processes. The thermal pretreatment sample (P1) had the highest methane yield, by increasing 88% in comparison with digesting the raw material. The maximum biogas production reached 253 mL/g volatile solids (VS). The largest substrate mass reduction was obtained by the alkaline pretreatment (P5). The VS of the alkaline-treated sample decreased about 60% in comparison with the raw material.

4503154 Anaerobic digestion of organic waste for biogas production

4503154 Anaerobic digestion of organic waste for biogas production