Start-up and microbial communities of a simultaneous nitrogen removal system for high salinity and high nitrogen organic wastewater via heterotrophic nitrification

Abstract

In this study, a simultaneous nitrogen removal system for high salinity and high nitrogen organic wastewater was developed in a pressurized biofilm reactor. The result showed that under the air supply rate of 200Lh−1, salinity of 3.0±0.2%, organic load of 10kgCODm−3d−1 and nitrogen loading of 0.185kgm−3d−1, the reactor started up rapidly and performed stably after 30days operation. Meanwhile, a simultaneous COD and nitrogen removal was achieved in the single-stage reactor, with COD, NH4+-N and TN removal efficiency of 97%, 99% and 98%, respectively. Denaturing gradient gel electrophoresis profile demonstrated that simultaneous nitrogen removal could be achieved through heterotrophic nitrification–aerobic denitrification, and the pivotal microorganisms were Flavobacterium phragmitis and Paracoccus denitrificans. The microbial community of salt-tolerant halophilic microorganisms was developed successfully. This study can provide a more efficient and feasible solution to treat high salinity organic wastewater.