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

Abstract

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 S^2- 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 non- sterilization 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.