Shifts on bacterial populations and biogas production by adding two industrial residues in co-digestion with cattle manure

Abstract

Anaerobic biodigestion (AB) figures as a sustainable alternative to avoid discharge of cattle manure (CM) in the environment, which results in biogas and biofertilizer. The anaerobic bioconversion of biomass to methane (CH4) via AB requires a multi-step biological process, including microorganisms with distinct roles. Here, the dynamics of acidogenic bacterial populations by classical microbiology, as well as biogas productivity by gasometer and chromatography, in the anaerobic co-digestion (co-AD) process were studied. This paper presents a performance evaluation of co-AD systems for the production of biogas using CM together with wastes from the Sewage Treatment Station (STS) of a brewery and ricotta cheese whey (RCW). The highest CH4 yield was observed in the biodigesters (RCW1, RCW2 and RCW3) fed with CM in addition to RCW. These results were generally coherent with the observed active bacterial communities affirming the stability of the process. The search revealed that the type of substrate added in coAD, Carbon/Nitrogen (C:N) ratio and Ammonia Nitrogen (NH3-N) were the most influential factors that explained many of the variations of the microbiota in the biodigesters (BRE1, BRE2 and BRE3) fed with CM in addition to wastes from the STS of a brewery. This study demonstrated that there is a good potential for the use of RCW in the production of biogas and its further conversion into energy. These findings could provide some fundamental and technical information for the co-treatment of industrial derived wastes in centralized AB facilities, in a sustainable manner with high process capacity and methane recovery.