Microbial Effects on Nitrogen Circulation and Transformation on Water-sediment Interface of Source Water Reservoir

Nitrogen circulation and transformation on water-sediment interface of Source Water Reservoir was studied through comparative experiment between sterilization incubation and non-sterilization incubation. The results showed that NH4+-N concentration in non-sterilization group continually increased and NO3- decreased by 97.7%. In the sterilization group, there was no obvious change except the increase caused by diffusion. The S2- produced by sulfate reducing bacteria (SRB) weakened the denitrification. The content of TN and organic matter in the non-sterilization sediment samples decreased 26.28% and 18.37% respectively. After incubation, the quantity of ammonifiers, denitrifying bacteria and SRB increased greatly in the sediment of nonsterilization group. Therefore it can be concluded that microbes accelerated nitrogen circulation and conversion on water-sediment interface. Anaerobic condition is an important factor for NH4+-N release. SRB can inhibit denitrification, thus slow down the nitrogen removal rate of sediment.