某湖泊水中亚硝胺类消毒副产物前体物及其去除特性研究

发布时间：2018-01-15 14:24

本文关键词：某湖泊水中亚硝胺类消毒副产物前体物及其去除特性研究　出处：《清华大学》2014年博士论文　论文类型：学位论文

【摘要】：饮用水氯胺消毒会产生具有强烈致癌性的新型消毒副产物亚硝胺,引起国内外供水界的高度重视。本文对我国华东地区某湖泊水中亚硝胺生成特征、前体物、去除特性及机理进行了较为全面系统的研究。首次将极性快速分析法(PRAM)用于水源水亚硝胺前体物组分的解析,与传统树脂富集法相比,更为突出了前体物的带电性特征,且操作简便、结果可靠。该湖泊水中亚硝胺生成潜能(NAFP)较高(175-330ng/L),且呈现明显季节变化,秋冬季较高,春季较低。亚硝胺前体物以小分子量(MW0.5k Da)、非极性弱极性、正电性组分为主,各组分分别占62.3%、60%和63.4%。与典型亚硝胺前体物(如二甲胺、雷尼替丁)性质不同,该湖泊水中亚硝胺前体物主要以弱酸性物质为主(61%),p H值越低呈电中性前体物越多,越易被C18固相萃取小柱吸附。采用小试与中试试验开展净水工艺去除亚硝胺前体物的研究,通过对处理过程中前体物各组分变化的解析,确定了混凝沉淀、臭氧氧化、生物活性炭的炭吸附和生物降解的去除效果、组分特征和作用机理。混凝沉淀可去除10-21.5%的前体物,主要是非极性弱极性组分;2mg/L臭氧能去除34.1%前体物,氧化主要去除非极性弱极性组分,对正负电组分没有选择性;投加足量活性炭几乎可以100%地去除前体物,吸附对各组分都有去除,对极性组分去除稍弱;微生物降解约去除80%的亚硝胺前体物,主要是极性、带正电组分。由于各有机物组分对亚硝胺生成都有贡献,而不同工艺去除组分有所不同,因而采用组合工艺才能更为彻底地去除亚硝胺前体物,降低出厂水亚硝胺生成风险。运行初期,常规+臭氧/活性炭组合工艺能去除94%的亚硝胺前体物,最终出水中NAFP20ng/L,实际生成量2ng/L,运行1年后去除率降低至78%。炭池运行1年后对前体物去除率由89%降低至69%,主要由活性炭吸附性能下降引起;此时炭池去除的前体物中有58.5%通过生物作用去除,14.4%通过活性炭吸附去除,其余的既可能通过生物去除也可能通过活性炭吸附去除。炭池反冲洗能将亚硝胺前体物去除率由62%提高至80%。进一步研究生物作用去除亚硝胺前体物机理发现外加碳源可促进亚硝胺前体物的去除,外加氮源对其去除影响不大。因而,预氧化提高生物炭池进水有机物的可生物降解性有利于微生物共代谢去除亚硝胺前体物。采用分子生物学手段研究了亚硝胺前体物降解菌的微生物种群结构,发现变形菌、芽孢杆菌和鞘氨醇单胞菌可能是其主要降解菌。
[Abstract]:Chloramine disinfection in drinking water will produce a new disinfection by-product nitrosamine with strong carcinogenicity, which has attracted great attention from domestic and foreign water supply circles. In this paper, the characteristics and precursors of nitrosamine generation in a lake water in East China are discussed. The removal characteristics and mechanism of nitrosamines in source water were studied systematically and comprehensively. For the first time, the polarity rapid analytical method (PRAM) was used to analyze the components of nitrosamines precursor in source water, which was compared with the traditional resin enrichment method. The results show that the potential of NAFPs in the lake water is 175-330 ng / L ~ (-1) with obvious seasonal variation. In autumn and winter, it was higher than that in spring. The precursor of nitrosamine was small molecular weight (MW0.5k), non-polar weak polarity and positive electric component (62.3%). Different from typical nitrosamine precursors (such as dimethylamine, ranitidine), nitrosamines precursor in the lake water is mainly composed of weak acidic substances. The lower the pH value is, the more electrically neutral precursors can be adsorbed by C18 solid phase extraction column. The removal of nitrosamine precursors by water purification process was carried out in pilot and pilot experiments. The removal effects of coagulation precipitation, ozone oxidation, carbon adsorption and biodegradation of activated carbon were determined by analyzing the changes of precursor components in the treatment process. Coagulation precipitation can remove 10-21.5% of precursors, mainly non-polar weakly polar components. 2 mg / L ozone can remove 34.1% precursors, oxidation mainly removes non-polar weak polar components, and has no selectivity for positive and negative components. Adding sufficient amount of activated carbon can remove the precursor almost 100%, and the adsorption can remove the components of each component, but the removal of polar component is slightly weak. Microbial degradation of about 80% of nitrosamines precursors, mainly polarity, with positive components. Because each organic component has a contribution to nitrosamine formation, but different removal process components are different. Therefore, the combined process can remove the nitrosamine precursor more thoroughly and reduce the risk of nitrosamine formation in the factory water. In the early stage of operation, the conventional ozone / activated carbon combination process can remove 94% of the nitrosamines precursor. Finally, NAFP 20ng / L, actual output 2 ng / L, the removal rate decreased to 78% after one year of operation, and the removal rate of precursors decreased from 89% to 69% after one year of operation of the carbon pool. It is mainly caused by the decrease of the adsorption property of activated carbon. At this time, 58.5% of the precursors removed by the carbon pool were removed by biological action. 14. 4% of the precursors were removed by activated carbon adsorption. The others can be removed by biological or activated carbon adsorption. The removal rate of nitrosamine precursor can be increased from 62% to 80 by backwashing of carbon pool. Further study on biological action removal of nitrosamine precursor machine. It was found that the addition of carbon source could promote the removal of nitrosamine precursors. The addition of nitrogen source has little effect on its removal. Pre-oxidation can improve the biodegradability of influent organic matter in biochar tank. The microbial population structure of nitrosamine precursor degradation bacteria was studied by molecular biological method. Proteus, Bacillus and sphingomonas may be the main degrading bacteria.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU991.2

【相似文献】