Combinatorial Effect of Process Parameters on the Rate of Biogas Production and Rate of Substrate Degradation Following Anaerobic Digestion of Food Waste and Rumen Content

Abstract

In this study, the combinatorial effect of process parameters on the rate of biogas production and rate of substrate degradation following anaerobic digestion of food waste and rumen content using mixture design (Combined I-optimal) within the Design Expert (version 13) environment. Results showed that the rate of biogas production, rate of bio-methane production and rate of substrate degradation inside the 100 bio-digesters ranged from 0 to 38.04 L/Kg VS, 0 to 23.14 L/Kg VS and 0 to 79.20 %, respectively. The highest rate of biogas production (38.04 L/Kg VS), highest rate of bio-methane production (23.14 L/Kg VS) and highest rate of substrate degradation (79.20 %) were observed in bio-digester 57 at food waste (0.30 kg), rumen content (0.30 kg), water content (0.40 kg), temperature (34.0^oC), pH (9.0), number bio-digester of agitation per day (4 time/day) and retention time (32 days), respectively. The rate of biogas/bio-methane production and rate of substrate degradation can vary, with varying process factors/parameters in anaerobic digestion processes. Bio-digesters with anaerobic co-digestion of the food waste and rumen content appeared to be significantly more productive in terms of biogas/bio-methane production rate and substrate degradation rate compared to the bio-digesters with anaerobic mono-digestion of either food waste or rumen content regardless of the presence other process factors/parameters within the boundaries of this investigation.