Insect biomass shows promise as an alternative animal feedstuff with a low climate effect. Industrial insect rearing generates residual materials, such as feed remains and insect excrements, ...so-called insect frass, which exhibits a high organic content. Commonly, these residues are utilized as soil amendment. Information on the suitability of these residues for biogas production is rather scarce. The energetic utilization of insect frass as feedstock for anaerobic digestion (AD) would allow for the simultaneous residue material reduction and bioenergy production. Additionally, synergies in heat management could arise using the exhaust heat of the biogas plant in the insect farming process. In laboratory-scale anaerobic digestion trials, the specific methane yield (SMY) of six different insect frass samples from black soldier fly (Hermetia) rearing were tested in batch biochemical methane potential (BMP) tests. Further, semi continuous anaerobic digestion trials on a lab scale using continuously stirred tank reactors (CSTRs) were carried out with Hermetia insect frass from a pilot plant operation in order to determine the digestibility and process stability of the AD process. The BMP results showed SMY values of the different insect frass samples ranging from 201 ± 9 to 287 ± 37 mL/gVS that are similar to those of other animal excrements, such as cow or pig manure already been used as feedstock in agricultural biogas plants. Results of the semi-continuous digestion of insect frass from the pilot plant operation showed a SMY value of 167 ± 15 mL/gVS, suggesting no process-inhibiting effect caused by the feed material. Although, the high nitrogen content must be taken into account for stable AD performance.
This study aims to evaluate how inoculum’s origin affects the methane yield of palm oil mill effluent (POME) by measuring the specific methanogenic activities (SMA) and bio-methane potential (BMP) of ...POME at different dilutions (100, 80, 60, 40, and 20 % of initial POME) and by using active anaerobic sludge (as inocula) from 3 palm oil mills (S1, S2, S3). The anaerobic digesters were operated in batch mode at a temperature of 40 °C until methane generation ceased. The corresponding SMA were 0.0159, 0.0098 and 0.0333 gCOD /(gVSS d) for S1, S2 and S3, respectively. The results showed that POME without dilution gave the highest cumulative biogas, 4162, 2857 and 2678 mL for S2, S3 and S1, respectively. However, 20 % dilution from original POME gave the highest methane yield (as BMP) 126, 88 and 84 mL CH4/gCOD removed for S2, S3 and S1, respectively. In this study, 2 mathematical models were selected including the corrected Gompertz equation and Gompertz two substrate models. They were applied to characterize the kinetics of the anaerobic digestion processes and to compare the BMP data from the experiments. Both models could represent all BMP data satisfactory although only Gompertz 2 substrate model showed almost perfect fitting and could characterize the influence of slowly degradable portion of POME. Accordingly, the slowly degradable portion of POME was estimated to be 10 % of total COD.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Anaerobic co-digestion in wastewater treatment plants is looking increasingly like a straightforward solution to many issues arising from the operation of mono-digestion. Process modelling is ...relevant to predict plant behavior and its sensitivity to operational parameters, and to assess the feasibility of simultaneously feeding a digester with different organic wastes. Still, much work has to be completed to turn anaerobic digestion modelling into a reliable and practical tool. Indeed, the complex biochemical processes described in the ADM1 model require the identification of several parameters and many analytical determinations for substrate characterization. A combined protocol including batch Biochemical Methane Potential tests and analytical determinations is proposed and applied for substrate influent characterization to simulate a pilot-scale anaerobic digester where co-digestion of waste sludge and expired yogurt was operated. An iterative procedure was also developed to improve the fit of batch tests for kinetic parameter identification. The results are encouraging: the iterative procedure significantly reduced the Theil’s Inequality Coefficient (TIC), used to evaluate the goodness of fit of the model for alkalinity, total volatile fatty acids, pH, COD, volatile solids, and ammoniacal nitrogen. Improvements in the TIC values, compared to the first iteration, ranged between 30 and 58%.
An economy based on biofuels requires production methods which are economically and technically competitive. The production of biogas from biomass by microorganisms is an attractive and ambitious ...possibility. Marine and lake algae represents a biomass source that could be used for biogas production and their extraction is of benefit for the aquatic environment reducing eutrophication. The goal of the experimental work is to evaluate the algae biomass naturally present in lagoon environment and analyze the biogas resulting from the anaerobic digestion. The Biomethane Potential (BMP) of macrophytes with inoculums from a sewage sludge treatment plant was measured at the University of Perugia. The CH4 content of biogas was approximately 52%, cumulative CH4 yield of 217 Nm3 /t SV was observed after 41 days of digestion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
RESUMO O biogás é proveniente da decomposição anaeróbia natural da matéria orgânica. A energia obtida através do principal componente, metano (CH4), representa uma faixa de 50 a 65% em volume do ...total de biogás gerado e um poder calorífico de, em média, 9,9 kWh/m3 em condições normais de temperatura e pressão (CNTP). Diante dos benefícios energéticos e da prevenção de emissões gases tóxicos, limitando-se a carência de normas técnicas (NBR's) no Brasil referente a um procedimento para a determinação da produção do biogás, foram estudados, testados e analisados alguns métodos de caracterizações e monitoramentos dos principais fatores envolvidos no processo de degradação dos resíduos sólidos urbanos (RSU) para o aproveitamento energético do biogás, resultando, desta forma, na proposta de um procedimento operacional para o teste do Potencial Bioquímico do Metano (BMP). O teste resultou em dados positivos comparados a trabalhos já realizados na literatura, o qual obteve um volume médio de 282,7 NL.kg-1MS de biogás em 90 dias.
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