Biogas production by anaerobic co-digestion of cattle slurry and cheese whey (original) (raw)
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Biogas production from co-digestion of a mixture of cheese whey and dairy manure
Biomass and Bioenergy, 2010
In this study, daily amount of biogas of different mixtures of cheese whey and dairy manure, rates of production of methane, removal efficiencies of chemical oxygen demand (COD), total solid (TS) matter and volatile solid (VS) matter from the mixtures were investigated at 25 and 34 C. In the experimental studies, two different solid matter rates (8% and 10%) were studied. The hydraulic retention times (HRTs) were 5, 10 and 20 days. Removal efficiencies and amount of biogas produced in each HRT were determined. Maximum daily biogas production was obtained as 1.510 m 3 m À3 d À1 at HRT of 5 days in the mixture containing 8% total solid matters at 34 C and the methane production rate was around 60 AE 1% in all experiments. Maximum removal efficiencies for TS, VS and COD were found as 49.5%, 49.4% and 54%, respectively at HRT of 10 days in the mixture containing 8% total solid matters at 34 C.
Biogas production from cheese whey: past, present and future
Cheese whey is a type of dairy wastewater that is either discharged directly into the environment or the local sewer, treated with the primary object to meet effluent discharge limits, or used as a resource to produce, for example, biofuels, single cell proteins, animal feed after condensation, sweetener after crystallization of lactose, xanthan gum, glycerol and 2,3 butanediol upon fermentation. This review has been dedicated to the production of biofuels, specifically biogas, from cheese whey. We aim to provide the reader with a brief account of how knowledge in the field of biogas production from cheese whey effluents has evolved, the current status quo, and identify areas that should be addressed in the near future. Based on the review of ca. 100 research papers published over the past 25 years following facts were extracted: A large body of knowledge exists at lab- and pilot-scale. It has been shown that cheese whey wastewater can be used either as a primary or co-substrate for the production of biomethane and biohydrogen. Amongst the reactors studied, high-rate anaerobic digesters can be operated at organic loading rates up to 40 g COD L-1 d-1 with relatively low hydraulic retention times (0.5-10 d). The 1980ies have seen the implementation of the first fully integrated systems in New Zealand and Ireland. It was also concluded that anaerobic treatment of full-strength cheese whey, despite COD removal efficiencies of up to 99%, cannot meet the stringent discharge criteria set forth in most countries thus requiring an aerobic polishing step. As the biogas technology reaches technical maturity and enters the commercial stage in the dairy industry, more data and reliable statistics are needed to evaluate the economical and operational feasibility at the industrial scale, including how we deal with the anaerobic digester effluent. Life cycle and carbon footprint assessments of the overall treatment process are to be carried out before it can be promoted as a technology that can contribute towards sustainable development and a more environmentally friendly agro-industry. Cooperation and promotion should be encouraged among agro-industries, government and national research institutes as well as providers of technology, operators and clients of digestion products. Consequently, decision makers will be able to choose the best technologies and options to promote the digestion products. It should also be recognized that the competition between different processes exploiting cheese whey as a resource will continue due to technological advances.
Acta Scientiarum. Technology
The search for new sources of energy has intensified these days due to the environmental impacts caused by fossil fuels. The tripod composed of energy, food and water is the base of human existence. Food production implies the generation of organic waste and the need to manage it properly. The dairy and pig farming sectors have an essential role in the Brazilian economy, producing a large amount of waste. One energy and environmental alternative to treat this issue is anaerobic digestion. Here we aimed to optimize the production and composition of biogas obtained from cheese whey and swine manure. Batch-scale laboratory tests were performed on bench anaerobic digesters for 65 days with 6 triplicates loaded with different proportions of cheese whey and swine manure. The proportion of 50% cheese whey and 50% swine manure presented the highest biogas production and methane concentration (CH4).
Co-digestion of Livestock Wastes for Biogas Production
Bioengineering and Bioscience, 2016
Co-digestion of cow dung, poultry dropping and pig manure was carried out in batch digesters at mesophilic temperature for twenty-eight days to determine the biogas generating potentials. The wastes were also digested individually for the same period and under the same conditions. The physicochemical and bacteriological characteristics were determined using standard techniques. The range of P H, temperature, percentage moisture content, percentage chemical oxygen demand, percentage carbon content, and the bacterial loads of the wastes slurries before digestion were 6.
Waste Management, 2018
Anaerobic co-digestion of sewage sludge and other organic wastes at a wastewater treatment plant (WWTP) is a promising method for both energy and material recovery. However, transportation and storage of wastes to WWTP may be the bottleneck for the successful implementation of this technology. In case of wet wastes and wastewater it is possible to reduce their volume and as a result the transportation and storage cost by using a drying process. During this study, the optimization of biogas production from sewage sludge (SS) was attempted by co-digesting with a dried mixture of food waste, cheese whey and olive mill wastewater (FCO). A series of laboratory experiments were performed in continuouslyoperating reactors at 37°C, fed with thermal dried mixtures of FCO at concentrations of 3%, 5% and 7%. The overall process was designed with a hydraulic retention time (HRT) of 24 days. FCO addition can boost biogas yields if the mixture exceeds 3% (v/v) concentration in the feed. Any further increase of 5% FCO causes a small increase in biogas production. The reactor treating the sewage sludge produced 287 ml CH 4 /L reactor /d before the addition of FCO and 815 ml CH 4 /L reactor /d (5% v/v in the feed). The extra FCO-COD added (7% FCO v/v) to the feed did not have a negative effect on reactor performance, but seemed to have the same results. In all cases, the estimated biodegradability of mixtures was over 80%, while the VS removal was 22% for the maximum biomethane production (5% v/v). Moreover, codigestion improved biogas production by 1.2-2.7 times.
Enhanced biogas production using cow manure to stabilize co-digestion of whey and primary sludge
Environmental Technology, 2013
Anaerobic digestion (AD) has long been used to treat different types of organic wastes especially in the developed world. However, organic wastes are still more often considered as a waste instead of a resource in the developing world, which contributes to environmental pollution arising from their disposal. This study has been conducted at Bugolobi Sewage Treatment Plant (BSTP), where two organic wastes, cow manure and brewery sludge were co-digested with primary sludge in different proportions. This study was done in lab-scale reactors at mesophilic temperature and sludge retention time of 20 d. The main objective was to evaluate the biodegradability of primary sludge generated at BSTP, Kampala, Uganda and enhance its ability of biogas production. When the brewery sludge was added to primary STP sludge at all proportions, the biogas production rate increased by a factor of 3. This was significantly (p<0.001) higher than observed gas yield (337±18) mL/(L•d)) in the control treatment containing (only STP sludge). Co-digesting STP sludge with cow manure did not show different results compared to the control treatment. In conclusion, Bugolobi STP sludge is poorly anaerobically degradable with low biogas production but co-digestion with brewery sludge enhanced the biogas production rate, while co-digestion with cow manure was not beneficial.
Biogas production from co-digestion of dairy manure and food waste
Bioresource Technology, 2010
The effect of manure-screening on the biogas yield of dairy manure was evaluated in batch digesters under mesophilic conditions (35°C). Moreover, the study determined the biogas production potential of different mixtures of unscreened dairy manure and food waste and compared them with the yield from manure or food waste alone. A first-order kinetics model was developed to calculate the methane yield from different mixtures of food waste and unscreened dairy manure. The methane yields of fine and coarse fractions of screened manure and unscreened manure after 30 days were 302, 228, and 241 L/ kgVS, respectively. Approximately 93%, 87%, and 90% of the biogas yields could be obtained, respectively, after 20 days of digestion. Average methane content of the biogas was 69%, 57%, and 66%, respectively. Based on mass balance calculations, separation of the coarse fraction of manure would sacrifice about 32% of the energy potential. The methane yield of the food waste was 353 L/kgVS after 30 days of digestion. Two mixtures of unscreened manure and food waste, 68/32% and 52/48%, produced methane yields of 282 and 311 L/kgVS, respectively after 30 days of digestion. After 20 days, approximately 90% and 95% of the final biogas yield could be obtained, respectively. Therefore, a hydraulic retention time (HRT) of 20 days could be recommended for a continuous digester. The average methane content was 62% and 59% for the first and second mixtures, respectively. The predicted results from the model showed that adding the food waste into a manure digester at levels up to 60% of the initial volatile solids significantly increased the methane yield for 20 days of digestion.
Biogas production from co-digestion of different proportions of food waste and fresh bovine manure
Biomass Conversion and Biorefinery, 2020
The present study aimed to evaluate the process of anaerobic co-digestion of different proportions of food waste and fresh bovine manure. The experiments were carried out in the laboratory (using 250-mL reactors) and in a pilot-scale biodigester (8 m 3). The laboratory experiment was conducted with batch feed systems testing three food waste (FW) and bovine manure (BM) ratios: 0:1, 1:2, and 3:1 (equivalent to 0, 33, and 75 % of food waste in the digester substrate, respectively). The pilot-scale biodigester had a continuous feed system and received a 1:2 FW:BM mixture ratio. The highest accumulated biogas production in the laboratory was 273 mL g-1 of volatile solids (VS) in the treatment with the 1:2 FW:BM ratio. Concentrations of volatile fatty acids (VFA) greater than 8 g L-1 inhibited methane production, except in the treatment without food waste. In the pilot-scale biodigester, concentrations of VFA were below the inhibitory threshold, and the biogas and methane yields were 271 L kgVS-1 and 220 L kgVS-1 , respectively. Therefore, food waste can be successfully co-digested with fresh bovine manure in continuous feed digesters, with an initial organic load rate of at least 2.74 kgVS m-3 day-1. Future studies should aim to test progressive increases in food waste load to identify the threshold for inhibition.
Biogas Production from Co-digestion of Substrates: A Review
2016
Sustainable development is the projected demand of all nations at present. Only 20 percent of world’s primary energy requirement is met by renewable sources like solar and wind energy, hydropower, biomass, municipal and agri-wastes. Especially energy recovery from municipal and agri – wastes have gained importance due to two – fold reason: i. waste volume reduction, ii. energy recovery. The present review article focuses onto detailed aspects of some exhaustive research work in the field of energy generation by co-anaerobic digestion of several potential organic sources with cattle manure. Codigestion of substrates have been preferred over mono-digestion due to several benefits associated with it. Carbon to nitrogen (C/N) ratio has been identified as the key parameter for improving the digestion of substrates. The average C/N ratio of 20 – 30 has been stated as optimum for maximum yield of biogas and corresponding methane in it by almost all workers referenced below. Mostly, specific methane production, ultimate methane production, methane production rate has been determined for evaluating the co-digestion process. Improvement in C/N ratio, higher bio-degradability, effective volatile solids (VS) removal, eco-friendly sludge production has been regarded as merits of co-digestion process.
Engenharia Agrícola, 2017
This research aimed to evaluate the biogas production during the anaerobic biodigestion process of dairy cattle manure, with and without solids separation. Sixteen biodigesters of the batch type were used, each one with 2L of capacity, supplied with manure in four different conditions: (1) pure manure, after washing the floors of the free stall system; (2) manure after the solids separator; (3) manure after the solids separator and sand decanter and (4) manure with the solid retained in separator solids, dissolved in water. The hydraulic retention time was of 196 days. The highest reductions of volatile solids (VS) were obtained for the biodigesters supplied with manure that went through some process of solids separation. The highest potential of methane production(CH4) obtained was of 0.2686 m³ CH4 kg-1 of added VS, supplied to digesters with manure after solids separator. The best potential for biogas and methane production was observed when there was a reduction of the solids concentration in the manure and, in this case, the hydraulic retention time can be reduced, which reduces the volume of the biodigester and the cost of implementation and maintenance, but the highest biogas production occurred in the biodigesters without solids separation.