常规水处理工艺中卤乙腈的生成特性及控制技术研究

发布时间：2018-10-16 11:04

【摘要】：目前我国给水厂主要采用氯消毒的方式,大约占到99%,氯消毒具有强氧化性、使用成本低、使用操作简单等优点。但是,氯和水体中的有机物质接触后会发生反应,生成消毒副产物(Disinfection by-products, DBPs),人们已经在饮用水中检测出超过700种对人体有害的氯化消毒副产物。由于消毒副产物具有致癌、致畸、引起人的肝和神经中毒、代谢紊乱等危害,在近年来受到了越来越多的关注。为了保障饮用水安全,关于消毒副产物的研究已成为科研工作者的研究重点。试验通过对长春市某净水厂进厂水、沉淀池出水、滤池出水、以及消毒后出水进行采样检测,分析各工艺单元中消毒副产物卤乙腈及其前体物的生成及去除情况。结果表明,原水中卤乙腈前体物总含量为44.04μg/L,其中含量最高的是二氯乙腈前体物,为27.03μg/L,约占到卤乙腈前体物总量的61.38%,溴氯乙腈与三氯乙腈前体物分别占总体的18.98%和14.03%,二溴乙腈前体物含量最少,只占到5.63%。各工艺对卤乙腈前体物去除率最高的是混凝沉淀工艺单元,去除率达到39%；其次是过滤工艺的26%；加氯消毒后对卤乙腈前体物有一定的去除作用,但效果不明显,去除率只有14%。由于氯的氧化作用,消毒后水中产生了更多的卤乙腈,相比滤池出水增加了4.91μg/L,约51%。预氧化试验中,使用高锰酸钾作为预氧化剂,高锰酸钾投加量为1.5mg/L、PAC投加量为30.0mg/L时,水样中的卤乙腈前体物含量最少。高锰酸钾能够将水中部分有机物质氧化,减少了卤乙腈生成量,但投加量应控制在一定范围内,过多效果反而不好。消毒试验中,二氧化氯的投加量与卤乙腈生成量成正比,在确保消毒效果的同时应尽量减少二氧化氯投加量；卤乙腈的生成量与反应时间相关,反应时间越长,生成的卤乙腈越多,在8h后卤乙腈生成量明显减少。三个模拟净水处理工艺中,工艺三使用高锰酸钾预氧化、二氧化氯消毒出水中卤乙腈生成量最小为10.20μg/L,比工艺一降低了34%,工艺二比工艺一的出水中卤乙腈生成量下降了24%。从各工艺出水中卤乙腈生成量由少到多的顺序选优结果为：工艺三工艺二工艺一。
[Abstract]:At present, chlorine disinfection is mainly used in water supply plants in China, accounting for about 99%. Chlorine disinfection has the advantages of strong oxidation, low cost, simple operation and so on. However, chlorine reacts with organic substances in water to produce disinfection by-products (Disinfection by-products, DBPs), has detected more than 700 harmful disinfection by-products in drinking water.) In recent years, more and more attention has been paid to disinfection by-products because of carcinogenesis, teratogenicity, liver and nerve poisoning, metabolic disorders and other hazards. In order to ensure the safety of drinking water, the research on disinfection by-products has become the focus of scientific research. Through sampling and testing the inlet water, sedimentation tank effluent, filter effluent and disinfection effluent of a water purification plant in Changchun City, the formation and removal of halogen acetonitrile and its precursors in each process unit were analyzed. The results showed that the total content of halogen acetonitrile precursor in raw water was 44.04 渭 g / L, and the highest content was dichloroacetonitrile precursor. The content of bromoacetonitrile and trichloroacetonitrile were 18.98% and 14.03 渭 g / L, respectively, and the content of dibromoacetonitrile precursor was the least (5.63%). The highest removal rate of halogen acetonitrile precursor was coagulation sedimentation process unit (39%), followed by filtration process (26%). After chlorine disinfection, the removal rate of haloacetonitrile precursor was not obvious, but the removal rate was only 14%. Because of the oxidation of chlorine, more haloacetonitrile was produced in the disinfected water, which increased 4.91 渭 g / L, about 51g / L, compared with the filter effluent. In the pre-oxidation test, when potassium permanganate was used as preoxidizer and the dosage of potassium permanganate was 1.5 mg / L 30.0mg/L, the content of haloacetonitrile precursor in water sample was the least. Potassium permanganate can oxidize some organic matter in water and reduce the amount of halogen acetonitrile, but the dosage should be controlled within a certain range. In the disinfection test, the amount of chlorine dioxide is directly proportional to the amount of halogen acetonitrile, and the amount of chlorine dioxide should be reduced while the disinfection effect is ensured, the amount of halogen acetonitrile is related to the reaction time and the reaction time is longer. The more Halogen acetonitrile is produced, the less Halogen acetonitrile is produced after 8 h. In the three simulated water purification processes, potassium permanganate preoxidation was used in process 3. The minimum amount of halogen acetonitrile produced in chlorine dioxide disinfection effluent was 10.20 渭 g / L, which was 34% lower than that of process 1, and the production of halogen acetonitrile in process 1 was reduced by 24%. The result of selecting the amount of halogen acetonitrile from each process is as follows: process 3, process 2, process 1.
【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.2

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