Bacterial agents affected bacterial community structure to mitigate greenhouse gas emissions during sewage sludge composting

The present work studied the influence of bacterial agents (B1, B2) and bamboo biochar (BB) on greenhouse gas emissions and bacterial community during the sewage sludge composting. Results showed that compared with CK, the total methane emissions of C, B1, B1C, B2, and B2C treatments declined by 16.4%, 25.2%, 45.4%, 7.8%, and 44.4%, respectively. The total N2O emissions of C and B1C treatments declined by 5.1% and 3.7% while B1, B2, and B2C treatments increased the total N2O emissions by 6.7%, 21.6%, and 10.4%, respectively. These results illustrated that the addition of BB is conducive for reducing greenhouse gas emissions while different bacterial agents have various effects. According to pearson correlation analysis, N2O emissions and Acidimicrobiia, Alphaproteobacteria, Gammaproteobacteria, and Tepidiformia have strong negative correlation while positive correlation with Bacilli and Clostridia. Methane emissions have a strong negative correlation with Actinobacteria. CO2 emissions have a strong positive correlation with Bacilli.