Feasibility Study of Anaerobic Codigestion of Municipal Organic Waste in Moderately Pressurized Digesters: A Case for the Russian Federation

Abstract

Anaerobic digestion (AD) is a promising option to obtain renewable energy in the form of biogas and reduce the anthropogenic impact on the environment. In recent years there has been increasing interest in using pressurized digesters to improve the quality of biogas. However, maintaining high overpressure increases the requirements for the explosion safety of digesters. Consequently, there are natural limitations in the available technologies and facilities suitable for full-scale operation. In this work, we aimed to evaluate the possibility of using overpressure in the digester to improve the efficiency of codigestion of common municipal organic waste–sewage sludge and the organic fraction of municipal solid waste. Three levels of moderate excess pressure (100, 150 and 200 kPa) were used to meet requirements of existing block-modular anaerobic bioreactors based on railway tanks, which are widely utilized for AD in the Russian Federation. There was no significant change in methane content in biogas (65% ± 3%) at different values of overpressure, hydraulic retention time (HRT) and organic loading rate (OLR). The maximum methane and energy production rates (2.365 L/(L·day) and 94.27 kJ/(L·day), respectively) were obtained at an overpressure of 200 kPa, HRT of 5 days and OLR of 14 kg VS/(m3·day). However, the maximum methane yield (202.44 mL/g VS), energy yield (8.07 kJ/g VS) and volatile solids (VS) removal (63.21%) were recorded at an overpressure of 150 kPa, HRT of 7 days and OLR of 10.4 kg VS/(m3·day). The pressured conditions showed better performance in terms of AD stability at high OLRs.

Modularisation and Modularity as a Circular Economy Approach for the Biogas Production

“…Anaerobic digestion (AD) is a promising option to obtain renewable energy in the form of biogas and reduce the anthropogenic impact on the environment (KOVALEV et al, 2022). Biogas production may come "from various substrates, such as cow dung, poultry droppings, cassava biomass, vegetable and fruit waste, and their mixture" (SAWYERR et al, 2020).…”

“…There are natural limitations in the available technologies and facilities suitable for the fullscale operation of biogas modularised plants (KOVALEV et al, 2022). In the agro-industrial complex, there is still a problem with processing a large amount of organic waste that accumulates around livestock farms (ROMANIUK et al, 2021).…”

Energy Optimization for Agriculture and Agroengineering Systems

“…In another work [7], the authors aimed to evaluate the possibility of using overpressure in the digester to improve the efficiency of codigestion of common municipal organic waste-sewage sludge and the organic fraction of municipal solid waste. An article [8] examines existing methods for assessing the homogeneity of feed mixes in the feed industry and agriculture.…”