Insights into influences of sucrose amendment on nitrification and denitrification in sewage sludge composting

Sucrose amendment could promote ammonia assimilation and reduce nitrogen loss in sewage sludge (SS) composting, but the effects of sucrose amendment on nitrification and denitrification are still unknown that were firstly researched in present paper. Result showed that sucrose amendment reduced 33.0% of N2O emission by changing the physicochemical indexes, nitrogen forms, related bacteria and functional genes. In the sucrose treatment, the higher nitrifying bacteria community, amoA and nxrA genes abundance were, the lower hao, narG、nirS、nirK and norB genes abundance were. Based on the correlation analysis, the number of nitrifying bacteria was significantly positively correlated with NO3− and nxrA abundance, indicating that sucrose amendment promoted the growth of nitrifying bacteria, the contents of NO3− and the activity of nitrite oxidation. Moreover, contents of NO2− were positively correlated with N2O emission, narG, nirS and norB abundance, indicating that denitrification was the main path of N2O generated.