[Factors Affecting Nitrate Concentrations and Nitrogen and Oxygen Isotope Values of Effluents from Waste Water Treatment Plant].

Urban domestic sewage is one of the important nitrate (NO) sources for surface water; however, their NO concentrations and nitrogen and oxygen isotope values (N-NO and O-NO) remain unclear, and the factors affecting NO concentrations and N-NO and O-NO values of effluents in the waste water treatment plant (WWTP) are still unknown. Water samples in the Jiaozuo WWTP were collected to illustrate this question. Influents, clarified water in the secondary sedimentation tank (SST), and effluents of the WWTP were sampled every 8 h.