Enhanced volatile fatty acid production in sequencing batch reactor: Microbial population and growth kinetics evaluation

Abstract

A sequencing batch reactor (SBR) with a working volume of 8 L and an exchange ratio of 20% was used to enrich microorganism for the production of volatile fatty acid. The treatment system managed to suppress the growth of volatile fatty acid (VFA)-utilising methanogen and increased the VFA output. The enhancement reactor managed to achieve stable accumulation of VFA without producing methane gas. The average VFA production was 43.8 % more than that of the original VFA content in raw POME. After achieving steady state, 16S metagenomic analysis was conducted to identify the species in the SBR. Further, the growth kinetic of the enriched microorganism were determined in batch experiments. The decay coefficient (bD) and biomass yield (Y) were found to be 0.1665 day-1 and 0.174 mg biomass/mg COD consumed, respectively. The maximum specific growth rate (μmax) was estimated to be 0.636 day-1 while the half saturation constant (Ks) with respect to COD was determined to be 12752 mgCOD/L.