Methanogenesis of organic wastes and their blend in batch anaerobic digester: Experimental and kinetic study

Abstract

Abstract The scarcity of the fossil fuels and increasing energy demand urges the production of sustainable source of energy. The uncontrolled generation of wastes and their easy accessibilities gained a significant attention towards its use for the synthesis of renewable energy like biomethane. In order to cope up with the energy demand and urgency of alternative non-conventional energy source, the present study is focused on improvisation of biogas production qualitatively and quantitatively from different substrates viz. paper waste, Parthenium hysterophorus, canteen waste, and their mixture. The enhancement of the methane potential is accomplished by treating these substrates with catalyst (poultry litter, silica gel and cow urine) and active inoculum (gobar gas slurry) under the standard anaerobic digestion condition. The methanogesis process was carried out in a 1 l batch digester at 1:1 ratio of water:feed under mesophilic temperature (37 °C) for hydraulic retention time of 30 days. Moreover, cumulative gas yield for considered substrates were 167.32 ml/g VS, 149.05 ml/g VS, 197.72 ml/g VS, 290.69 ml/g VS respectively with methane content in biogas for each substrate of 25.5%, 56.8%, 60%, 62% respectively. Among various kinetic models studied, first order kinetic model was found to be best to describe the kinetics of biomethane synthesis for all employed wastes with maximum fitting accuracy (R2 = 0.966). Results of the study confirm the enrichment of quality and quantity of the product gas. The experimental study also revealed that the process is prominent for the efficient production of biomethane to meet the excessive energy thrust.