Anaerobic co-digestion of waste activated sludge and fish waste: Methane production performance and mechanism analysis

The performances of anaerobic co-digestion (AcD) of waste activated sludge (WAS) and fish waste (FW) were studied through mesophilic biochemical methane potential test. Mixtures of various compositions (0, 1.5, 3, 6 and 10% of FW on the volume basis) were tested as the AcD substrates. Experimental results showed that 1.5% and 3% of FW addition could enhance the cumulative methane production remarkably, increasing from 212.3 mL CH4/g VSfed (100% WAS) to 410.1 mL CH4/g VSfed and 683.8 mL CH4/g VSfed, respectively. However, methane producing was inhibited severely with more than 6% of FW addition, whose cumulative methane production dramatically decreased to approximately 51 mL CH4/g VSfed. Mechanism analysis showed that large amounts of fatty acids accumulation occurred during the AcD with FW addition above 6%, leading to methanogenesis process failure. Microbial community analysis showed that methane producing during AcD was dominated by hydrogenotrophic and methylotrophic methanogenesis pathways led by Methanobacterium and Methanomassiliicoccus. (c) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study on anaerobic co-digestion of waste activated sludge and fish waste showed that adding 1.5% and 3% of fish waste could enhance methane production, while adding more than 6% inhibited methane production severely. Microbial community analysis revealed dominance of hydrogenotrophic and methylotrophic methanogenesis pathways during anaerobic co-digestion.