An industrial scale testing and analysis of waste-to-energy production from various substrates by employing a modern anaerobic digestion plant

Abstract

This industrial scale study has tested, monitored and analyzed the waste-to-energy yield for different ratios of mixed livestock manure and mixed vegetable waste substrates using a modern industrial scale pilot anaerobic digestion (AD) plant, which consists of four interlinked digesters, having a volume of 272.5 m³. Five substrate treatment ratios between mixed livestock manure (L) and mixed vegetable waste (V) have been tested and they are denoted with L1V0, L0.8V0.2, L0.6V0.4, L0.4V0.6 and L0.2V0.8. The pilot AD plant runs in a semi-continuous mode having a retention time of 30 days for each treatment and a substrate loading rate of 4000 kg d−1 (avg.). The subsequent energy yield in terms of biogas/biomethane in m3.10−3 kg−1 VS (volatile solids), have been recorded as 89/46, 146/98, 133/82, 124/75 and 96/55 for five treatment ratios, respectively. The yield of biogas and methane from the largest to smallest are in the order of L0.8V0.2 > L0.6V0.4 > L0.4V0.6 > L0.2V0.8 > L1V0. For the purpose of biogas yield prediction, a statistical analysis is deliberated to further testify the measured biogas yield data in order to determine a correlation between the yield and its influenced variables. The least significant difference (LSD) and regression coefficient (R2) values are discussed. As such the values of LSD05, LSD01 and R2 have been found as 18, 32 and 0.93 for L1V0 and as 29, 51 and 0.99 for L0.8V0.2, respectively, but they are significantly different for other substrate treatment ratios.