Disinfection byproducts in drinking water and regulatory compliance: A critical review

Disinfection by-products (DBPs) are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States (US) indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule (ICR) database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations (e.g. 62.2% versus 89.6% for total trihalomethanes). Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.     

Haloacetic acids in swimming pool and spa water in the United States and China

The objective of this study is to investigate the occurrence of haloacetic acids （HAAs）, a group of disinfection byproducts, in swimming pool and spa water. The samples were collected from six indoor pools, six outdoor pools and three spas in Pennsylvania, the United States, and from five outdoor pools and nine indoor pools in Beijing, China. Five HAAs （HAA5）, including monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid were analyzed. Total chlorine, pH and total organic carbon concentration were analyzed as well. Results indicated that the levels of HAA5 in swimming pools and spas in the United States ranged from 70 to 3980μg·L^-1, with an arithmetic average at 1440μg·L^-1 and a median level at 1150μg·L^-1. These levels are much higher than the levels reported in chlorinated drinking water and are likely due to organic matters released from swimmers＇ bodies. The levels of HAA5 in swimming pools in China ranged from 13 to 332μg·L^-1, with an arithmetic average at 117μg·L^-1 and a median level at 114μg·L^-1. The lower HAA levels in swimming pools in China were due to the lower chlorine residuals. Results from this study can help water professionals to better understand the formation and stability of HAAs in chlorinated water and assess risks associated with exposures to HAAs in swimming pools and spas.     

紫外消毒在城市污水处理中的研究进展

介绍城市污水消毒的必要性,对常用污水消毒技术进行现状分析及技术经济比较,紫外线消毒有望成为替代传统液氯消毒的较佳选择.阐述紫外线消毒原理及工程上的应用.最后对紫外消毒技术进行总结.     

水中天然有机物的分类特性及其卤代活性

利用XAD树脂对原水中的天然有机物进行富集分类 ,将其分为腐植酸、富里酸、亲水酸和其它亲水物质等 4种有机组分 .考察了原水中各有机组分的分布及其在加氯消毒过程中的三卤甲烷生成量、生成速度及耗氯量情况 .研究结果表明 ,原水中的主要成分是富里酸 ,占有机物总量的50.7% ,其它3种成分所占比例相对较小 ;原水具有较高的三卤甲烷生成能力 ,富里酸是生成三卤甲烷的主要有机组分 ;对各有机组分卤代活性的研究表明 ,腐植酸、富里酸和亲水酸具有较高的卤代活性 ,其它亲水物质的卤代活性较低 ;从各有机组分的三卤甲烷生成速度及与氯反应速度来看 ,腐植酸、富里酸及亲水酸具有较快的三卤甲烷生成速度 ,与氯的反应速度也较快 ,而其它亲水物质的三卤甲烷生成速度及与氯的反应速度均较低 .     

饮用水中的消毒副产物及其控制策略

消毒副产物（disinfection by-products,DBPs）是在饮用水消毒时由消毒剂与有机或无机前体物反应生成的一类次生污染物,其由于具有致癌、致畸和致突变的三致特性在全球范围内广受关注.聚焦于饮用水中的DBPs,介绍了DBPs的主要分类和研究历程,汇总了多地饮用水中常见DBPs的浓度水平以及全球饮用水水质标准对DBP指标的管控要求.随后系统介绍了饮用水中DBPs的控制策略,包括源头控制、过程控制、末端控制以及协同控制这4大类,并对各类控制方法的优缺点进行了分析.评述了中国的DBPs研究的现有水平和未来趋势,并展望了未来有关DBPs控制方法的研究方向.一方面,在评价某种工艺或技术对DBPs的控制效果时需要考虑DBPs浓度和水质综合毒性的变化,另一方面,建议关注耦合源头、过程和末端控制技术的协同控制方法,兼顾从源头到龙头每个节点,实现对饮用水中各类DBPs的高效控制.     

二氧化氯与氯联合消毒对饮用水中消毒副产物的影响

为了研究二氧化氯与氯联合消毒工艺过程中消毒副产物的形成规律以及特点,探讨二氧化氯对氯化消毒副产物的控制效果,对我国北方某市使用同一水源的4家水厂消毒工艺进行全面的采样与检测,并对各项消毒副产物检测结果进行了全面的分析.结果表明,二氧化氯与氯联合消毒比单纯液氯消毒形成的三卤甲烷平均降低74.39%,卤乙酸平均降低40.6...     

饮用水消毒副产物:化学特征与毒性

饮用水消毒过程中消毒剂与天然有机物(NOMs)反应生成消毒副产物(DBPs).本文针对氯、氯胺、二氧化氯、臭氧4种主要消毒方式产生的消毒副产物,综述了10类DBPs的化学特性、毒性和分析方法.具体包括:三卤甲烷(THMs)、卤乙酸(HAAs)、溴酸盐(BrO3-)、亚氯酸盐(CIO2-)、卤乙腈(HANs)、致诱变化合...     

气体ClO2对室内空气的消毒研究

气体ClO2与其他常用过氧化物消毒剂和含氯消毒剂在空间消毒方面比较有诸多优势.气体ClO2对各种微生物具有很好的杀菌消毒作用,而且不会产生有毒、有害的氯化物,较之液态ClO2具有更好的扩散性、穿透性和使用均匀性,特别适用于对大面积环境微生物的杀菌消毒.     

MIEX树脂特性及其在饮用水处理中的应用

阐述了MIEX阴离子交换树脂的特性及其在饮用水处理中对消毒副产物前质、色度、浊度、藻类等的去除效果.对近年来MIEX树脂与超滤、活性炭、臭氧等工艺组合的应用情况进行了介绍,初步分析了MIEX树脂用于净水处理的经济性.     

氯和紫外消毒过程中胞外抗性基因的产生特征

考察了城市污水氯和紫外消毒过程中不同物理形态的胞外抗性基因的产生行为与及微生物群落的关联特征.结果表明,氯消毒尽管使胞内抗性基因丰度下降,但使结合型胞外抗性基因丰度明显上升（0.7±0.1）log,而游离型胞外抗性基因丰度下降（0.2±0.1）log.紫外消毒也使胞内抗性基因下降,但使游离型胞外抗性基因显著上升（0.4±0.2）log,而结合型胞外抗性基因丰度下降（0.3±0.1）log.氯消毒后,结合型胞外DNA（a-eDNA）中变形菌门丰度下降而其他菌门的丰度上升,细菌多样性指数由4.2上升到4.7;而游离型胞外DNA（f-eDNA）中变形菌门上升了6.6%,多样性指数则从3.5降低到2.8.紫外消毒后,a-eDNA中变形菌门丰度下降了36.6%,多样性则上升到4.8,而f-eDNA中细菌丰度变化较小.分子生态网络分析揭示了抗性基因与细菌间广泛的寄存关系,tetA、tetX、sulI和sulII分别与17、15、15和5种菌属间存在共现性,表明抗性基因潜在宿主的变化是导致消毒后胞外抗性基因产生的关键原因.本研究表明氯和紫外消毒不能消除抗性基因风险,反而通过导致不同胞外抗性基因的大量产生,使风险的形式发生变化.