Exploring the mechanisms of organic matter degradation and methane emission during sewage sludge composting with added vesuvianite: Insights into the prediction of microbial metabolic function and enzymatic activity

Abstract Effect mechanisms of organic matter (OM) degradation and methane (CH 4 ) emission during sewage sludge (SS) composting with added vesuvianite (V) were studied by high-throughput sequencing (HTS) and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). Results show that the addition of V accelerated the OM degradation and decreased the cumulative CH 4 emissions by 33.6% relative to the control. In addition, V significantly decreased the mcrA gene abundance and the methanogen community richness at the genus level. PICRUSt also indicated that V strengthens the microbial metabolic function and enzymatic activity related to OM degradation, and reduced the enzymatic activity related to CH 4 production. Methanogens community variation analysis proved the ratio of carbon and nitrogen and moisture content are the significant variables affecting CH 4 emissions. Thus, optimizing the ratio of carbon and nitrogen and moisture content will decrease CH 4 emission during SS composting.