Influence of acidogenic fermented fish by-products with rice bran for sludge reduction and biogas recovery in anaerobic co-digestion

Abstract

The purpose of this study was to investigate the effects of acidogenic fermentation broth with rice bran (RFFB), tap water (TFFB), or raw fishery by-products (FBs) on sludge reduction and biogas production in an anaerobic co-digestion process. Acidogenic fermentation of FBs with rice bran was faster and produced more volatile fatty acids than that with tap water. Reduction efficiencies for chemical oxygen demand, volatile solids, and total solids were highest in RFFB. In the kinetic analysis, λ (d), which represents the duration of the lag phase, was shortest with RFFB (1.09 d) and highest in sewage sludge (8.86 d). As the loading amount of volatile solids and chemical oxygen demand increased, the amount of cumulative biogas also increased. Amount of produced methane and energy recovery were highest with RFFB (5.71 kWh). Anaerobic co-digestion of FFB and sewage sludge allowed reduced sludge and recovered energy using the discarded waste as an organic carbon source.