Investigation of the occurrence of N-nitrosamines and their formation potential in wastewater treatment plants

Abstract

 The objectives of this study were to determine the occurrence and fate of N-nitrosamines in wastewater treatment plants (WWTPs: X and Y), and to evaluate formation potential of N-nitrosamines on chlorination (FP_Cl) and efficiency of FP_Cl reduction by biological treatment. We also investigated the residual FP_Cl in the final discharge. As the results, the concentrations of N-nitrosamines in the influent were ranged from 3 to 237 ng/L. The removal efficiencies of N-nitrosamines were ranged from 28 to 99% by biological treatment. The production rates of N-nitrosamines were ranged from 14 to 66% by disinfection. The N-nitrosamines FP_Cl in WWTP X were higher than those in WWTP Y, and the efficiencies of N-nitrosamines FP_Cl reduction by biological treatment were ranged from 2 to 94% in WWTPs X and Y. The concentrations of residual N-nitrosamines FP_Cl were ranged from 2 to 848 ng/L in the both WWTPs. Thus, N-nitrosamines could be produced in water purification or reclamation plants using discharge from WWTPs.