Assessment of Sludge Reduction and Biogas Potential from Anaerobic Co-digestion Using an Acidogenically Fermented Fishery Byproduct with Various Agricultural Wastes

Abstract

Fishery byproducts were acidogenically fermented with agricultural wastes (corncob, cabbage waste, and fruit peel), and fishery acidogenic fermentation broth (FFB) was used to observe sludge reduction and biogas production in anaerobic co-digestion. The experiment was conducted using a batch test for 30 days in mesophilic conditions. Samples with FFB showed a short response delay time of 1.50–3.06 (day), and total solid (TS) and volatile solid (VS) removal efficiencies of 23–43% and 20–30%, respectively, which were higher than those without FFB. In addition, the process produced 2.63–3.86 times more biogas with a methane content of over 70%. These results indicate that FFB improves the biodegradability of sewage sludge and that microbial communities were activated in a short time during the anaerobic co-digestion process. In particular, the highest TS and VS removal efficiency, biogas production, and high methane content were observed in FFB with corncobs. This suggests that nutrients such as sugar and minerals in corncobs may have positively affected the activity of methane-producing archaea. The anaerobic co-digestion process, which combines FFB and sewage sludge, enhanced the treatment efficiency of sludge and has an advantage of energy recovery.