Co-digestion of Municipal Solid Waste and Other Waste Types at Different Mix Ratios in Biogas Production

Abstract

This study investigated the effect of varying feed mix ratio on biogas production from the anaerobic co-digestion of the organic fraction of municipal solid waste (OFMSW) with sewage sludge (SS) and with cattle dung (CD). Minimal sample pretreatment comprising slight reductions in particle size ( 50 mm) and thermal treatment were employed with the aim of mimicking the low energy, low-cost scenarios in developing countries. Feed mix ratios of 9:1, 8:2 and 7:3 was used and a control of only municipal solid waste (10:0) was also set up for comparison. Biogas production from the OFMSW+SS digesters was 0.043 m^-3, 0.041 m^-3 and 0.076 m^-3 for mix ratios of 9:1, 8:2 and 7:3, respectively. In the OFMSW+CD digesters, biogas production was 0.133 m^-3, 0.039 m^-3, and 0.154 m^-3 respectively. The control containing only OFMSW produced 0.042 m^-3 of biogas. While there was increased biogas production in the 7:3 digesters compared to the other digesters, the difference was not statistically significant (P > 0.05).