摘要
【目的】水厂浓缩池上清液是生产尾水回用的主要水源,揭示浓缩池上清液回用对含氮消毒副产物生成的影响,可为优化水处理工艺和降低饮用水健康风险提供科学依据。【方法】文中遴选6种CX_(3)R型含氮消毒副产物(二氯乙腈、溴氯乙腈、二溴乙腈、二氯乙酰胺、三氯乙酰胺和三氯硝基甲烷)和6种亚硝胺(亚硝基二甲胺、亚硝基吡咯烷、亚硝基二正丙胺、亚硝基二乙胺、亚硝基二苯胺和亚硝基吗啉)为典型含氮消毒副产物,基于中试试验研究了水厂浓缩池上清液回用对水处理流程中含氮消毒副产物生成势的影响。【结果】浓缩池上清液经消毒后待测含氮消毒副产物100%检出,其中CX_(3)R型含氮消毒副产物质量分数占比高达99.8%,卤代腈生成势为8.5~10.7μg/L,卤乙酰胺生成势为4.3~5.5μg/L,卤代硝基甲烷生成势为1.7~2.3μg/L,而亚硝胺生成势为14.7~19.1 ng/L。【结论】CX_(3)R型含氮消毒副产物生成种类中占主导的是二氯乙腈、二氯乙酰胺和三氯硝基甲烷,而亚硝胺生成种类中占主导的是亚硝基二甲胺和亚硝基吡咯烷。浓缩池上清液来源水质中,滤池反冲洗水相较于排泥水对浓缩池上清液中含氮消毒副产物生成的贡献更大。浓缩池上清液的回流比控制在3∶1时,上清液回用对原水中含氮消毒副产物生成势具有轻微改善作用,且不会对滤池出水含氮消毒副产物生成势产生明显影响。同时,浓缩池上清液连续回用不会造成含氮消毒副产物前体物在沉淀池排泥水和滤池反冲洗水中富集,说明以含氮消毒副产物为风险管控指标时,浓缩池上清液可在自来水处理过程中直接回用。
[Objective]Supernatant of thickening tank in water treatment plant serves as the primary source for process tail water reuse.Investigating the impact of reusing this supernatant on the formation of nitrogenous disinfection by-products(N-DBPs)provides a scientific basis for optimizing water treatment processes and mitigating associated drinking water health risks.[Methods]Effect of the reuse of supernatant from the concentration tank to raw water on the formation of potential changes of typical N-DBPs during the drinking water treatment processes was studied based on pilot-scale experiments.The typical N-DBPs studied in this paper include six CX_(3)R-type N-DBPs(i.e.,dechloroacetonitrile,bromochloroacetonitrile,debromoacetonitrile,dichloroacetamide,trichloroacetamide and nitrotrichloromethane)and six nitrosamines(i.e.,nitrosodimethylamine,nitroso pyrrolidine,nitroso di-n-propylamine,nitrosodiethylamine,nitrosodiphenylamine,and nitrosomorpholine).[Results]All the studied N-DBPs were formed when the supernatant was chlorinated.The formation of CX_(3)R-type N-DBPs contributed to 99.8%in weight percent of the formed N-DBPs.The formation potentials of the haloacetonitriles,haloacetamides,halonitromethanes,and nitrosamines were 8.5-10.7,4.3-5.5,1.7-2.3μg/L,and 14.7-19.1 ng/L,respectively.[Conclusion]Dichloroacetonitrile,dichloroacetamide and nitrotrichlorome-thane are the dominant CX_(3)R-type N-DBPs,while nitrosodimethylamine and nitroso pyrrolidine are the major nitrosamines formes during chlorination of the supernatant.Regard to the source waters of the supernatant,filtered backwash water provides more precursors of NDBPs compares to the sedimentation sludge water.Fixing the reflux ratio of the supernatant at 3∶1,the reuse of the supernatant alleviates the formation of N-DBPs from raw water,and has little effect on the formation of N-DBPs from filtered effluent.Simultaneously,the continuous reuse of the supernatant had little effect on the accumulation of precursors of N-DBPs in both the filtered backwash water and the sedimentation sludge water.This study suggests that the supernatant from the concentration tank can be directly reused to raw water when using the formation potential of N-DBPs during drinking water treatment processes as a risk control indicator.
作者
袁聪
周晨
祖振权
司佳蕾
陈晗
YUAN Cong;ZHOU Chen;ZU Zhenquan;SI Jialei;CHEN Han(Nanjing Water Group Co.,Ltd.,Nanjing 210002,China;College of Environment,Hohai University,Nanjing 210098,China)
出处
《净水技术》
2025年第8期55-62,108,共9页
Water Purification Technology
基金
南京水务集团有限公司科技创新项目(YF2022-010):尾水处理系统浓缩池上清液回用技术研究。
关键词
浓缩池上清液
回用
含氮消毒副产物
生成势
中试
supernatant of thickening tank
reuse
nitrogenous disinfection by-products(N-DBPs)
formation potential
pilot scale test
