饮用水处理臭氧—混凝交互作用研究

发布时间：2018-06-10 06:34

本文选题：臭氧预氧化 + 强化混凝　；参考：《山西大学》2012年硕士论文

【摘要】：随着工农业生产急速发展,环境污染问题日趋严重,水质标准不断严格化,传统水处理工艺已经不能满足人们对水质安全的要求。传统水处理工艺是由混凝、沉淀、过滤和消毒工艺共同组成的,为满足目前的水质标准要求,越来越多的水厂采用臭氧预氧化技术处理饮用水。臭氧可以去除水中色度和嗅味,还可改变有机物的性质,使之容易在后续处理中得到去除,但臭氧预氧化对混凝作用的影响说法不一。本文研究了臭氧预氧化、强化混凝和臭氧-混凝联用对水体污染物去除的影响。以模拟天然水体和化工废水为研究对象,使用不同碱化度的聚合氯化铝(PACl)和聚合氯化铁(PFC)作为混凝剂,采用静态烧杯实验和动态模拟实验相结合的方法,通过对出水水质指标检测,有机物GC-MS分析,比较了不同工艺对水体的处理效果,研究了臭氧预氧化与强化混凝作用的相互影响关系,初步探讨了臭氧-混凝联用去除水体有机污染物的作用机理。总结得出以下结论： (1)对模拟天然水体进行臭氧化处理后,采用不同碱化度PACl和PFC对臭氧化水体进行混凝作用,在混凝剂剂量相近的作用范围内,PACl (B=0)作用的水体较PACl(B=2)作用的水体,浊度去除率高出4.47%,UV254去除率高出31.89%；PFC(B=0)作用的水体较PFC(B=2)作用的水体,浊度去除率高出24.34%,UV254去除率高出12.11%,两种混凝剂作用下,藻类都可以完全去除,Chl-a的去除率皆在95%以上。可知碱化度(B=0)的混凝剂,其作用效果优于碱化度(B=2)的混凝剂。 (2)单独臭氧化与单独混凝作用处理过的水样,其浊度和DOC的去除率均低于臭氧预氧化后,再进行混凝处理过的水样。臭氧预氧化后进行混凝处理的水样,当臭氧浓度为3mg·L-1,混凝剂剂量为3mg·L-1时,浊度降到最低值0.736NTU, DOC的浓度下降到最低值0.9mg·L-1,其浊度和DOC的去除率均高于臭氧浓度为1mg·L-1,混凝剂剂量为3mg·L-’时作用过的水样。说明,经过臭氧预氧化,再进行混凝对于水样浊度和DOC去除作用效果显著。 (3)应用臭氧预氧化、强化混凝和臭氧混凝联用工艺处理模拟化工废水,通过出水GC-MS检测,可知原水以苯系物,醇类和酯类物质居多,还包含一些烷烃、醇类和酸类物质。臭氧预氧化处理过的水样,苯系物、烷烃类、醇类、酯类物质均未检出；强化混凝处理过的水样中,检出了绝大部分有机物；臭氧=混凝联用处理后,其有机物种类发生显著变化,仅检出部分醇类、酯类物质。说明臭氧-混凝联用处理对模拟化工废水中的绝大部分有机物的去除效果显著,明显优于单独混凝、臭氧氧化作用。 (4)臭氧强氧化作用表现在对水中难降解有机物长链的破坏,使之分解为分子量较小的有机物,这些有机物可促进混凝作用的进一步进行,主要表现在以下方面：一是臭氧会破坏有机物中的基团,降低有机物的表面电荷密度,并减少有机物与铁、铝离子的络合；二是臭氧在分解过程中形成的带正电荷中间产物也可以起到中和有机物表面电荷的作用。后续的混凝过程中,大分子有机物通过絮凝剂的吸附沉淀得以去除,而一些分子量较低的溶解性有机物则被氧化降解,从而使复杂有机物进一步减少。
[Abstract]:With the rapid development of industrial and agricultural production , the problem of environmental pollution is becoming more and more serious , and the water quality standard is increasingly strict . The traditional water treatment technology is composed of coagulation , precipitation , filtration and disinfection processes . In order to meet the current standards of water quality , more and more water plants adopt ozone pre - oxidation technology to treat drinking water .

In this paper , the effects of ozone pre - oxidation , intensified coagulation and ozone - coagulation on the removal of pollutants in water are studied .

( 1 ) After ozonization treatment of simulated natural water , the turbidity removal rate was 4.47 % higher than that of PACl ( B = 2 ) , and the removal rate of UV254 was 31.89 % higher than that of PACl ( B = 2 ) .
PFC ( B = 0 ) has a higher removal rate of 24.34 % than that of PFC ( B = 2 ) , and the removal rate of UV254 is 12.11 % . Under the action of two kinds of coagulant , the removal rate of algae can be completely removed , and the removal rate of Chl - a is above 95 % . It is found that the coagulant with alkalinity ( B = 0 ) has a better effect than that of alkalinity ( B = 2 ) .

( 2 ) The turbidity and DOC removal rate were lower than that of ozone pre - oxidation after ozone pre - oxidation . When the concentration of ozone was 3 mg 路 L -1 and the dosage of coagulant was 3 mg 路 L -1 , the turbidity and DOC removal rate were higher than the lowest value of 0.9 mg 路 L - 1 . The turbidity and DOC removal rate were higher than that of ozone concentration of 1 mg 路 L -1 and the dose of coagulant was 3 mg 路 L - 1 .

( 3 ) applying ozone pre - oxidation , strengthening coagulation and ozone coagulation combined process to treat the simulated chemical wastewater , and detecting by GC - MS of water , wherein the raw water contains benzene series , alcohols and ester substances , and contains alkane , alcohols and acid substances .
Most of the organic matters were detected in the treated water samples .
Ozone - coagulation combined with ozone - coagulation combined with ozone - coagulation combined with ozone - coagulation combined with ozone - coagulation treatment showed that the removal of most organic substances in the simulated chemical wastewater was remarkable , which was obviously superior to that of single coagulation and ozone oxidation .

( 4 ) The strong oxidation of ozone shows that it is difficult to degrade the long chain of organic matter in water so that it can be decomposed into organic matter with relatively small molecular weight . These organic matters can promote the further progress of coagulation , mainly in the following aspects : firstly , ozone can destroy the group in organic matter , reduce the surface charge density of organic matter , and reduce the complexation of organic matter with iron and aluminum ions ;
secondly , the positively charged intermediate products formed in the decomposition process of ozone can also play the role of neutralizing the surface charge of the organic matter . During the subsequent coagulation process , the macromolecular organic matters are removed by the adsorption and precipitation of the flocculating agent , and the soluble organic matters with lower molecular weight are oxidized and degraded , so that the complex organic matters are further reduced .
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R123.1

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