Dual stage co-digestion of waste Fat, Oil, Grease (FOG) for bio-energy recovery

Abstract

Dual-stage pulse-feed anaerobic co-digestion of fat, oil and grease (FOG) using acclimatized consortia showed improved methanation during application of increasing organic loading rates (OLRs). Highest methane yield was achieved in the 3rd OLR (61% FOG loading of total VS injected) with complete utilization of long chain fatty acids (LCFAs) in the digester. Assessment of microbial community revealed dominance of Intestinimonas and Megasphaera, and Levilinea in the fermenters for their acidogenic and acetogenic activities, respectively. Syntrophomonas (26%) predominantly showed the β-oxidation ability and syntrophy with mixotrophic methanogens, Methanosarcina (93%) to facilitate the methanation through complete degradation of FOG in the digesters. Thus, pulse-feed operation in dual-stage anaerobic co-digestion of FOG will contribute maximize the methanation through complete utilization.