ZHANGXin-ran,DONGShuang-shi,ZHAIJia-xin,et al.Formation Mechanisms of Nitrogenous Disinfection By-products in UV/Chloramine Process[J].China Water & Wastewater,2023,39(5):31-37.
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Formation Mechanisms of Nitrogenous Disinfection By-products in UV/Chloramine Process

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第39卷 Number: 第5期 Page: 31-37 Column: Date of publication: 2023-03-01
Author(s):
ZHANG　Xin-ran1; 2; 3;  DONG　Shuang-shi1;  ZHAI　Jia-xin4;  REN　Peng-fei5
（1. Key Laboratory of Groundwater Resources and Environment ， Jilin University， Changchun 130021， China； 2. School of Environmental Science and Engineering， Sun Yat-sen University， Guangzhou 510275， China； 3. Shenzhen Research Institute of Sun Yat-sen University， Shenzhen 518000， China； 4. Guangzhou Research Institute of Environmental Protection， Guangzhou 510620， China； 5. Guangzhou Municipal Engineering Design & Research Institute， Guangzhou 510001， China）
Keywords:
UV/chloramine process;  nitrogenous disinfection by-product;  nitrogen isotope tracer;  dichloroacetonitrile
Abstract:
In view of the high toxicity of nitrogenous disinfection by-products in UV/chloramine process, the formation behavior and mechanism of dichloroacetonitrile (a typical nitrogenous disinfection by-product) was investigated, and the control strategy was proposed. Compared with chloramine system, the UV/chloramine system reduced the dichloroacetonitrile production of three amino acids by 26.6%-46.7%, but significantly promoted the dichloroacetonitrile production of fifteen phenolic substances. The dichloroacetonitrile production of three humic substances in the two processes was basically the same. The nitrogen isotope (15N) tracing showed that the 15N-dichloroacetonitrile formed in the UV/chloramine system accounted for more than 70% of the total dichloroacetonitrile during the treatment of three amino acids, indicating that chloramine was an important precursor of dichloroacetonitrile, rather than nitrogenous organics in water. The results also proved that dichloroacetonitrile in the UV/chloramine system was mainly produced through the “aldehyde pathway”. A series of aldehyde and nitrile intermediates were identified by using tyrosine as a representative compound, and then the formation pathway of dichloroacetonitrile in UV/chloramine system was analyzed. In the practical engineering application of UV/chloramine process, it is recommended to pretreat the water with high phenol content, prolong the reaction time as far as possible, shorten the contact time of post-chloramination and adjust the pH to alkaline condition, so as to reduce the formation of dichloroacetonitrile.
Last Update: 2023-03-01