Microbial Analysis and Methane Assessment of Trinary Anaerobic Co-Digestion of Organic Fraction of Municipal Solid Waste

Anaerobic co-digestion (ACoD) has been adjudged as an efficient technology to advance the goal of climate change adaptability and carbon neutrality during waste treatment and bioenergy generation. Prior to digestion integration, an evaluation of the compatibility of the waste streams is critical to enhanced bioenergy output. This study examined the methane potential, microbial ecology, and kinetics during the co-digestion of organic fraction of municipal solid waste (OFMSW), sewage scum (SS), and a blended mixture of 1 part of new and 2 parts of mature leachate (LB) through mesophilic biochemical methane potential (BMP) test. Synergistic interaction within the mixtures increased methane yield by up to 92% (486.7 mL/gVS) over the treatment of OFMSW alone (252.3 mL/gVS). Likewise, the methane yield of LB-containing mixtures was enhanced by 16–41.5% over LB treatment alone (344 mL/gVS). Model estimates by modified Gompertz (MG) and logistic function (LF) were conclusive that the mixtures caused the methane production rate to improve by up to 16% from OFMSW alone and by at least 22% from LB alone. Furthermore, microbial analysis of mixtures revealed the proportion of LB in the mixture had a higher influence on the diversity than OFMSW. Even though acetoclastic Methanosaeta was more dominant, methane production was via a dual methanogenic pathway associated with both acetoclastic Methanosaeta and hydrogenotrophic Methanospirillum. Finally, the results obtained provide an insight on ACoD as a sustainable waste management strategy to enhance bioenergy production and reduce emissions through the recirculation of multiple heterogeneous waste streams into economic use.