Enhanced performance of sewage sludge anaerobic digestion under different organic loading rate by MW-H2O2 pretreatment combined with two-stage configuration: based on kinetics and microbial community analysis

Abstract: This study analyzed the enhanced performance of sewage sludge anaerobic digestion under different organic loading rate based on kinetic models and microbial community. Results showed that high organic loading rate (4 g VS/L d) could result in obvious decrease of methane production and VS reduction. While microwave pretreatment and combined with two stage configuration could enhance the performance, namely, 26.99% and 36.50% of more methane production. The improvement of hydrolysis rate (khyd) due to pretreatment was important based on first-order model analysis. But the methane production rate was still decreased though with pretreatment, thus a decrease of methane production or apparent degradability (fd) was observed. This performance was related to the changes of microbial community especially methanogenesis pathways. It was concluded that complex methanogenesis pathways (acetoclastic, hydrogenotrophic and methylotrophic methanogenesis) exist to tolerate the high concentration of ammonia and consume away the high concentration of substrates such as acetate and hydrogen. But this complex methanogenesis pathways greatly relied on the hydrogen transfer, thus a low methane production rate was observed.