Odor emission impact assessment of Zhengwangfen wastewater treatment plant in Beijing

An odor impact assessment had been carried out in order to evaluate the negative impact on the population living in the neighborhood of Zhengwangfen wastewater treatment plant (WWTP) in Beijing. The results indicated that the discharged NH3 and H2S concentrations were highest in the pretreatment and biological treatment units, while the discharged odor index was highest in the pretreatment, biological, and sludge treatment units in the two existing WWTPs. Using the method of the odor index evaluation for H2S and NH3, we concluded that the maximum concentrations of NH3 and H2S in Zhengwangfen WWTP were 0.0043 and 0.059 mg/m(3), respectively. On the basis of Gaussian point source diffusion model, the maximum protective distance of different treatment units was 196.43 m, which indicated that the 200 m setback distance for WWTPs, dictated by local regulation, appeared to be sufficient under usual operating and normal weather conditions.