自来水加氯消毒副产物及其前体物（THMFP）的研究与发展

介绍了目前对饮用水中三卤甲烷等加氯消毒副产物及其前体物（THMP）的研究状况,特别突出了对于混凝与活性炭吸附相结合去除消毒副产物的前体物的研究,最后讨论了这一研究领域未来的发展方向。     

配水管网水质变化的研究(Ⅲ)--三卤甲烷的研究

以腐殖酸为三卤甲烷形成的前驱物质,确定ＴＨＭ生成的反应级数为二级。引入了ＴＨＭ生态能（ＴＨＭＦＰ）的概念,将ＴＨＭ的自下而上作为ＴＨＭＦＰ、余氯浓度、滞留时间及温度的函数,开创性提出了三卤甲烷浓度分布的水质模型。利用此模型结合配水管网的水力分析与计算可以求出配水管网中任一节点的ＴＨＭ浓度。三卤甲烷浓度分布的水质模型用于实际的配水管网,计算值与观测值取得了较好４的一致性,证明了本研究方法及所提出的水     

煮沸对自来水中氯仿含量的影响

为了解管网末梢自来水及其在加热煮沸过程中致癌有机物——氯仿（CHCl3）含量的变化，采用不同的加热器、运用不同的加热方式对我国南方某地区管网末梢的自来水进行了加热煮沸处理，并对不同加热煮沸时间的水样进行了色质联机分析。结果发现，氯仿含量与热水器的功率、加热煮沸的方式及水中自由余氯含量均有关系。不管采用何种原水、何种加热器和加热方式，若煮沸后使水保持数分钟的沸腾状态均可使水中的氯仿含量降低到5μg／L以下的安全水平。     

A pilot plant evaluation of the Magnetic Ion EXchange® process for the removal of dissolved organic carbon at Draycote water treatment works

Natural organic matter (NOM) in water sources is undesirable for customers because it reacts with chlorine to form trihalomethanes (THMs), which can be harmful to health, and other organochlorine compounds that can cause taste complaints. A new Magnetic Ion EXchange process (MIEX^® DOC) has been reported as being successful in removing NOM from raw water. The aim of this research was (a) to evaluate the performance of the MIEX^® process in removing NOM from hard, lowland water on a pilot plant scale and (b) to compare the performance of the MIEX^® process with low pH coagulation DAF, in particular, with respect to reducing THM levels. A 45 and 40% reduction in the amount of NOM and in the levels of THMs, respectively, in chlorine‐dosed water was achieved when the MIEX^® process was used with dissolved air flotation (DAF).     

Microbiological and Trihalomethane Responses to Booster Chlorination

Two zones of a water distribution supply area receiving treated surface water were used to study the effect of booster chlorination on bacterial regrowth. In the first year of the study general patterns of bacterial regrowth were observed, and in the second year one of the areas was booster chlorinated at the outlet from a surface reservoir. In both years of the study the heterotrophic plate counts showed a seasonal pattern. In the second year there was a large increase in plate counts from mid-July to October in both of the study areas. During this period, booster chlorination was unable to prevent bacterial regrowth. The addition of chlorine to produce an initial free chlorine residual of 0.5 mg/1 resulted in a reduction in bacterial numbers, but with further retention in the distribution system bacterial regrowth occurred. There was little increase in the trihalomethane (THM) concentration following booster chlorination, but booster chlorination appeared to increase the assimilable organic carbon concentration.     

芳香类有机物在氯化反应过程中的特性研究

选择几种在受污染水源水中常见的、具有代表性的芳香类有机物进行氯化试验,测定三卤甲烷和卤乙酸的生成特性,并分析芳香类有机物的化学结构对生成消毒副产物的影响,结果表明：（1）各试验物质氯化生成消毒副产物的生成量和反应速率大小排序为：间苯二酚〉对苯二酚〉邻苯二酚〉苯酚〉苯胺〉苯甲酸〉硝基苯;（2）芳香类有机物苯环上官能团的性质、数量和位置等影响消毒副产物的生成;（3）邻苯二酚的氯化反应可分为快速反应阶段和慢速反应阶段。     

Photolytic treatment of organic constituents and bacterial pathogens in secondary effluent of synthetic slaughterhouse wastewater

The reduction and degradation of total organic carbon (TOC) and bacteria from a secondary effluent of synthetic slaughterhouse wastewater using vacuum-ultraviolet (VUV) and ultraviolet-C (UV-C) processes and their combination (UV-C/VUV and VUV/UV-C) were investigated. The TOC removal rates under continuous mode operation ranged from 5.5 to 6.2%. In addition, the treatment with the UV-C/H₂O₂ and VUV/H₂O₂ processes under continuous mode operation doubled the TOC removal rates 10.8 and 12.2%, respectively. The optimum molar ratio of H₂O₂/TOC was found to be 2.5 and 1.5 for the UV-C and VUV processes, respectively. It was observed that all photochemical processes were able to totally inactivate different strains of bacteria with concentrations up to 10⁵ CFU/mL within 27.6 s. Finally, a kinetic model was developed to simulate the TOC degradation from a secondary effluent of synthetic slaughterhouse wastewater.     

氯胺消毒对管网中消毒副产物的控制

相对氯消毒,氯胺具有消毒副产物生成量低的特点。本试验模拟管网,取典型的停留时间2d,考察了氯胺消毒时,pH和C12：N对管网中的消毒副产物（三卤甲烷和卤乙酸）浓度的影响。试验表明,消毒副产物的浓度及其含溴的程度基本上随着pH降低、C12：N升高而增大。试验条件下,氯胺生成的卤乙酸量大都高于三卤甲烷,并且以二卤乙酸为主,这和自由氯时所生成三卤甲烷多、卤乙酸以三卤乙酸为主的倾向正好相反。     

Determination of several common disinfection by-products in frozen foods

Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).     

Continuous and efficient removal of THMs from river water using MF membrane combined with high dose of PAC

A combination of microfiltration (MF) membrane with a high concentration (40 g/L of the reactor) of powdered activated carbon (PAC) efficiently and continuously removed trihalomethanes (THMs) and total organic carbon (TOC) from river water for a period of two months. Without PAC, the membrane reactor was able to remove less than 18% of THMs and less than 5% of TOC; with PAC, 65 to 95% of THMs and TOC were removed. Even though the THMs concentration in the influent was steadily increasing (reaching 50 μg/L), THMs concentration in the effluents from the reactors with PAC were consistently below 15 μg/L. While the MF membranes alone could not remove organics, PAC and microbial activity in the biofilm deposited on the PAC particles assured long term and continuous removal of THMs. No additional PAC was added into or removed from the reactors during the filtration period. Operational parameters such as the backwashing of the membrane, interval of the filtration cycle and biological pretreatment of the river water had a small effect on the extent of THMs removal, but they increased the filtration time prior to membrane cleaning and improved the overall performance of the reactors.