Effects of nitrate and glucose on the formation of chloronitromethane (CNM) under UV/chlorine treatment

Abstract

The existence of nitrate and dissolved organic matter (DOM) in water can react with chlorine disinfectant to form chloronitromethane (CNM) with high toxicity. The purpose of this study was to investigate the effects of NH4NO3, NaNO3 and Ca(NO3)2 on the formation of CNM under UV/chlorine treatment when glucose was used as the carbon source. The results showed that the formation of CNM from nitrate and glucose was raised first and then decreased. Among three types of nitrate, the potential of forming CNM from NH4NO3 was the largest. The concentration of CNM increased with increasing glucose concentration and UV intensity, while it decreased with increasing pH from 6 to 8. The analysis of various nitrogen showed that NH3-N and were converted into dissolved organic nitrogen (DON) under UV/chlorine treatment. The formation pathways of CNM from nitrate and glucose had been inferred under UV/chlorine treatment. Actual water samples were used to verify the laws found in the laboratory. The study could provide the development of a new disinfection method for water treatment and be useful for controlling the generation of CNM under UV/chlorine treatment.