Resource Recovery From Municipal and Industrial Organic Waste: The Effect of Substrate Type on Anaerobic Fermentation, Biological Denitrification, and Anaerobic Digestion

This study aims to recover volatile fatty acids (VFAs) from the anaerobic fermentation of industrial and municipal waste and investigate the effectiveness of using the produced VFAs as carbon sources for denitrification and as feedstocks for methane production via anaerobic digestion (AD) process. Six different wastes were used in this study, three industrial wastes: bakery processing and kitchen waste (BP+KW), whey powder (WP) and fat, oil, and grease (FOG), and three municipal wastes: food waste (FW), primary sludge (PS), and thickened waste activated sludge (TWAS). The experimental results showed that WP exhibited the maximum VFAs yield of 266 mg COD/ gTCOD added. In the denitrification experiments, all the fermentation filtrates exhibited higher specific denitrification rates (SDNRs) than conventional external carbon sources (i.e., methanol and acetate), with WP filtrate having the highest SDNR of 17.3 mg NOx-N/gVSS/hr. In the AD experiment, BP+KW and WP exhibited the highest methane yields of 354 and 350 mL CH4/ gTCOD added,respectively.