混凝、吸附工艺去除再生水中NDMA前驱物的研究

发布时间：2018-05-20 14:28

本文选题：NDMA + 中水回用　；参考：《山东大学》2017年硕士论文

【摘要】：城市污水的合理再生利用对环境、经济和社会均具有非常重要的意义,其可以有效地缓解水资源短缺,维护经济发展、促进环境恢复与平衡。城市污水经过生物处理后会存在很多带毒性的化学污染物、植物性营养物质和病原微生物,因此,城市污水排放前需要经过严格的消毒过程。这将不可避免的产生对生物有害的消毒副产物,其中二甲基亚硝胺(NDMA)便是毒性较强的一种亚硝胺类物质。NDMA以及其前驱物随水体排放进入河流后很难自然降解,其于下游饮用水厂消毒中将会再次生成NDMA,从而影响饮用水安全。本论文分析对比了 MBR和AAO生物处理工艺出水中的有机物特性及NDMA生成特性,并研究了氯化铁混凝、粉末活性炭吸附以及两种工艺联合使用对MBR、AAO出水中NDMA前驱物的去除作用。本论文还采用树脂分离、分子量分级、三维荧光光谱分析、红外光谱分析等技术对MBR、AAO出水及深化处理后的出水中的有机物组分进行表征,分析了 NDMA前驱物的特性以及各深度处理工艺对不同组分前驱物的作用效果。本文得出的主要结果如下:(1)污水的处理工艺不同导致了水样中DOM的组成成分不同,MBR工艺出水优于AAO出水,如MBR出水的浊度、DOC及UV254更低。MBR工艺出水中的有机物主要为多糖类、一级胺类和富里酸类物质,而AAO工艺出水中更多的是溶解性微生物产物、芳香性蛋白质类、多肽、氨基酸尤其为二级胺类物质。此外,MBR出水比AAO出水含有更多MW1 kDa和亲水性组分。两种水样中DOM组分的差异导致各类消毒副产物生成势的不同。MBR出水中常规的卤代消毒副产物的生成活性强于AAO出水,比如MBR出水中TCM生成量为526μg/mg-C,是AAO出水的13倍。相反,AAO出水的NDMA生成活性高于MBR出水,是MBR出水的1.43倍。(2)在AAO出水中,MW30 kDa及亲水性的有机物为NDMA的主要前驱物。混凝吸附联用工艺表现出最高的NDMA生成势去除率(57%),其次为单独的吸附工艺(50%)和混凝工艺(28%)。单独的混凝处理或吸附处理均更易去除MW30 kDa和HoA组分的前驱物。而混凝吸附工艺联用时,对MW30 kDa组分的前驱物的去除效率显著增加。因此,混凝吸附联用工艺可得到最高的NDMA生成势去除效率,去除率为57%。AAO出水中DOM的荧光强度均可被三种工艺有效降低,混凝去除更多的富里酸类物质,而吸附工艺可以去除更多溶解性微生物产物类和芳香性蛋白类物质。富里酸类物质的去除可以降低NDMA生成势,同时其比例的升高也伴随单位有机碳NDMA生成势的升高,说明富里酸类物质与氯消毒剂反应时有较高的NDMA生成活性。(3)在MBR出水中,NDMA的主要前驱物为MW1 kDa及亲水性的有机物。混凝工艺对MW100kDa的前驱物去除效果最佳,而吸附工艺更容易去除1-10 kDa组分的NDMA前驱物。两工艺对疏水酸性组分的NDMA前驱物的去除效果均比其他组分高。混凝更易去除富里酸类物质,而吸附更易去除溶解性微生物产物、芳香性蛋白类、多肽、氨基酸等物质。混凝和吸附对所有组分的DOM均有去除效果,这必然导致NDMA生成势下降。但混凝或吸附工艺对NDMA前驱物的去除程度低于其他有机物,这使得NDMA前驱物在DOM中占得比例增大。因此,氯与剩余的DOM反应将会有更高的NDMA生成率,使得单位有机碳NDMA生成势升高。
[Abstract]:The rational recycling of urban sewage is of great significance to the environment, economy and society. It can effectively alleviate the shortage of water resources, maintain economic development, and promote environmental recovery and balance. After biological treatment, there will be many toxic chemical contaminants, plant nutrients and pathogenic microorganisms after biological treatment. A strict disinfection process is required before urban sewage discharge. This will inevitably produce biological harmful disinfection by-products, in which two methylnitrosamine (NDMA) is a highly toxic nitrosamine substance.NDMA and its precursor is difficult to be degraded naturally after the water is discharged into the river, and it will be sterilized in a downstream drinking water plant. NDMA will be generated again, thereby affecting the safety of drinking water. In this paper, the characteristics of organic matter and NDMA formation in the effluent from the biological treatment process of MBR and AAO are compared and compared, and the removal effect of ferric chloride coagulation, powdered activated carbon adsorption and the combined use of two processes for the removal of NDMA precursors in MBR and AAO effluent. This paper also uses resin. Separation, molecular weight classification, three-dimensional fluorescence spectroscopy, and infrared spectroscopy were used to characterize the organic components in the effluent from MBR, AAO and deepened effluent. The characteristics of NDMA precursors and the effect of various depth treatment processes on the precursors of different components were analyzed. The main results of this paper are as follows: (1) sewage Different processing technology leads to different components of DOM in water samples. MBR process effluent is superior to AAO effluent, such as turbidity of MBR effluent, and organic substances in DOC and UV254 lower.MBR process effluent are mainly polysaccharide, first-order amines and rich acids, while AAO process water is more dissolved microorganism products, aromatic proteins, and more. Peptides, amino acids are especially two grade amines. In addition, MBR effluent has more MW1 kDa and hydrophilic components than AAO effluent. The difference of DOM components in the two water samples leads to the formation of conventional Halogenated Disinfection By-products in the different.MBR effluent of various kinds of disinfection by-products, which is stronger than the AAO effluent, for example, the TCM production of MBR in the effluent is 526 mu g/. Mg-C is 13 times the effluent of AAO. On the contrary, the NDMA generation activity of AAO effluent is higher than that of MBR effluent, which is 1.43 times higher than that of the effluent from MBR. (2) in AAO water, MW30 kDa and hydrophilic organic matter are the main precursor of NDMA. The highest NDMA generating potential removal rate (57%), followed by a separate adsorption process (50%) and coagulation process (2) 8%) the precursors of MW30 kDa and HoA components are more easily removed by separate coagulation treatment or adsorption treatment. The removal efficiency of the precursors of MW30 kDa components increases significantly when the coagulation adsorption process is combined. Therefore, the highest removal efficiency of NDMA generating potential can be obtained by coagulation adsorption process, and the removal rate is the fluorescence intensity of DOM in the effluent of 57%.AAO. It can be effectively reduced by three processes. Coagulation can remove more fulvic acids, and the adsorption process can remove more soluble microorganism products and aromatic proteins. The removal of rich acid can reduce the NDMA formation potential, and the increase of the ratio is also associated with the increase of the unit organic carbon NDMA formation potential. Acid substances have higher NDMA activity when they react with chlorine disinfectants. (3) in MBR water, the main precursor of NDMA is MW1 kDa and hydrophilic organic matter. The coagulation process is the best for MW100kDa precursor removal, while the adsorption process is easier to remove the NDMA precursor of the 1-10 kDa component. Two process for the NDMA precursor of the hydrophobic acid components. The removal efficiency of the substance is higher than that of the other components. Coagulation is easier to remove the rich acid, but the adsorption is easier to remove the dissolved microorganism products, aromatic proteins, peptides and amino acids. Coagulation and adsorption have the removal effect on all components of DOM, which inevitably leads to the decline of the NDMA potential. But the coagulation or adsorption process for NDMA precursors The degree of removal is lower than that of other organic compounds, which makes the NDMA precursor increase in the proportion of DOM. Therefore, the reaction of chlorine to the remaining DOM will have a higher NDMA generation rate, making the NDMA generating potential of the unit organic carbon up.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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