给水管网中污染物在管垢上的累积和释放

给水管网中,管垢是各种污染物的源和汇,但目前污染物在管垢中的累积释放特征尚缺乏系统研究.本文以实际的城市供水管网的球墨铸铁管和灰口铸铁管为对象,一方面采用扫描电镜(SEM)、能谱分析(EDS)、晶体衍射结构分析(XRD)等手段对其管垢进行表征,另一方面运用管段滞流反应器研究了三氯甲烷、铅、锰和锌等污染物滞流状态下在管垢上累积和释放特征.结果表明:同为铸铁管,使用一定年限后,管垢成分有所差异,灰口管管垢量较大,具有明显的锈蚀和管瘤出现,成分以二氧化硅、金属复合氧化物为主,而球墨管管垢量较小,以二氧化硅为主;随着初始浓度的提高,管垢对污染物的累积量逐步提高,对于三氯甲烷,其吸附量和释放量都非常低,而对于Pb、Mn和Zn 3种金属,管垢的吸附量远大于释放量,说明在实验条件下它们易累积不易释放,但水质条件的改变有可能引起大规模释放.研究结果对饮用水管网生物化学安全提出了更高的要求,为管网的饮用水安全保障提供了理论依据.     

Advances in photocatalytic disinfection of bacteria: Development of photocatalysts and mechanisms

Photocatalysis has attracted worldwide attention due to its potential in solar energy conversion. As a “green” advanced oxidation technology, it has been extensively used for water disinfection and wastewater treatment. This article provides a review of the recent progress in solar energy-induced photocatalytic disinfection of bacteria, focusing on the development of highly efficient photocatalysts and their underlying mechanisms in bacterial inactivation. The photocatalysts are classified into TiO₂-based and non-TiO₂-based systems, as TiO₂ is the most investigated photocatalyst. The synthesis methods, modification strategies, bacterial disinfection activities and mechanisms of different types of photocatalysts are reviewed in detail. Emphasis is given to the modified TiO₂, including noble metal deposition, non-metal doping, dye sensitization and composite TiO₂, along with typical non-TiO₂-based photocatalysts for bacterial disinfection, including metal oxides, sulfides, bismuth metallates, graphene-based photocatalysts, carbon nitride-based photocatalysts and natural photocatalysts. A simple and versatile methodology by using a partition system combined with scavenging study is introduced to study the photocatalytic disinfection mechanisms in different photocatalytic systems. This review summarizes the current state of the work on photocatalytic disinfection of bacteria, and is expected to offer useful insights for the future development in the field.     

饮用水含氮与含碳消毒副产物的生成潜能及其毒性

消毒副产物生成潜能测试常用于表征水中消毒副产物的前体物含量.不同于三氯甲烷等含碳消毒副产物,二卤代乙腈（DHANs）与二卤代乙酰胺（DHAcAms）等含氮消毒副产物在氯消毒的余氯存在下易分解,并且在氯胺消毒过程中可由氯胺提供氮源生成,因此常用于含碳消毒副产物的生成潜能测试方法（如Krasner提出的测试法）可能无法有效揭示DHANs与DHAcAms的前体物水平.本研究以三氯甲烷和氯醛两种含碳消毒副产物为对比,考察DHANs与DHAcAms在饮用水氯消毒与氯胺消毒过程中不同投氯量与反应时间下的生成量,识别最大生成量对应的消毒条件,以便更好地评估水样中DHANs与DHAcAms的前体物浓度.同时,对消毒过程中生成的这些挥发性消毒副产物进行毒性评价.结果显示,两个水样氯消毒的DHANs与DHAcAms生成量分别为6.19~40.08、1.34~15.75 nmol·mg^-1（mg^-1以TOC计）;氯胺消毒的DHANs与DHAcAms生成量分别为2.63~21.46、18.43~49.99 nmol·mg^-1.Krasner测试法条件下的DHANs与DHAcAms生成量均最低.在投氯量为TOC+8×NH₃-N、反应时间为24 h的氯消毒条件下,氯胺投加量20×TOC、反应时间为3 d的氯胺消毒条件下,两个水样具有最高水平的DHANs与DHAcAms生成量,并且消毒副产物毒性也高于Krasner法测试条件下的毒性水平.因此,氯消毒采用投氯量TOC+8×NH₃-N、反应时间24 h,氯胺消毒采用投加量20×TOC、反应时间3 d的生成潜能测试条件可能更好地揭示水中DHANs和DHAcAms的前体物浓度水平.     

垃圾填埋场渗滤液处理工艺研究

通过对垃圾填埋处理场渗滤液的处理工艺研究,并根据渗滤液的特性建立一套适合我国实际的 Ａ— Ｏ— Ｃ— Ｃ Ｌ 处理工艺．试验研究结果表明,出水ρ（ Ｃ Ｏ Ｄ Ｃｒ） ＝ ２０５ ．６ ｍｇ Ｌ－ １ 、ρ（ Ｂ Ｏ Ｄ５） ＝ １８ ．２ ｍｇ Ｌ－ １ 、ρ（ Ｎ Ｈ３ － Ｎ） ≈０ｍｇ Ｌ－ １ 、色度＝ ４０（ 倍） 、ｎ（ 大肠菌群数） ＝ ２００ 个 Ｌ－ １ ．达到 Ｇ Ｂ１６８８９ － １９９７《生活垃圾填埋污染控制标准》中对垃圾渗滤液排放要求的二级标准     

二氧化氯消毒时三氯甲烷形成量的研究

研究了二氧化氯与氯消毒时三氯甲烷的形成量。结果表明,氯可与水中有机物反应形成三氯甲烷,其形成量随水中有机物含量,氯投加量,ＰＨ值的升高而升高,当ＣＯＤ为３ｍｇ／Ｌ,投氧量为７ｍｇ／Ｌ时,经４８ｈ反应后,三氯甲烷形成量将超过国家标准规定的６０μｇ／Ｌ,二氧化氯不与有机物反应形成三氯甲烷,１１．３３ｍｇ／Ｌ的二氧化氯与ＣＯＤ为２．６７ｍｇ／Ｌ水样经４８ｈ反应,三氯甲烷形成量低于检出限,二氧化氯与氯复佤     

Bacteria inactivation by sulfate radical: progress and non-negligible disinfection by-products

● Status of inactivation of pathogenic microorganisms by SO₄^•− is reviewed. ● Mechanism of SO₄^•− disinfection is outlined. ● Possible generation of DBPs during disinfection using SO₄^•− is discussed. ● Possible problems and challenges of using SO₄^•− for disinfection are presented. Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade. The application of sulfate radicals in water disinfection has become a very promising technology. However, there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms. At the same time, less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms. This paper begins with a brief overview of sulfate radicals’ properties. Then, the progress in water disinfection by sulfate radicals is summarized. The mechanism and inactivation kinetics of inactivating microorganisms are briefly described. After that, the disinfection by-products produced by reactions of sulfate radicals with chlorine, bromine, iodide ions and organic halogens in water are also discussed. In response to these possible challenges, this article concludes with some specific solutions and future research directions.     

基于贝叶斯网络的给水管网消毒副产物生成因素分析

给水管网消毒副产物(disinfection byproducts,DBPs)的生成受管网环境因素、微生物群落特征和水厂未完全去除的有机物等多指标共同影响.各指标间相互关联形成复杂的网络结构,导致影响DBPs在管网内生成的主控因子较难确定.以广州某高校给水管网系统为研究对象,于2021年1～2月开展终端水质调查,利用吹...     

蛋白酶对水环境中病毒的灭活作用

以大肠杆菌噬菌体T₄作为模式病毒,研究了蛋白酶对病毒的灭活作用.试验结果表明:蛋白酶灭活病毒的效果明显. 适宜条件下,67.5u/mL的蛋白酶K处理1h对纯水中病毒(6.2×10⁵PFU/L)和生活污水中病毒(7.2×10⁵PFU/L)灭活率分别达到了99.4%和49.4%,处理3h的灭活率分别是>99.9%和81.1%;工业蛋白酶1398在75.0u/mL酶浓度下处理1h对纯水水中病毒(1.7×10⁵ PFU/L)灭活率达到74.4%.pH和温度对病毒灭活效果的影响不明显.     

中晚期垃圾渗滤液的处理研究

垃圾渗滤液的处理一直是近几年污水处理领域的热点和难点问题.采用"吹脱-SBR-混凝沉淀-氯化"处理工艺对中晚期垃圾渗滤液进行实验研究,确定了各工艺的最佳运行参数,并对SBR的强化进行了新的探索.结果表明,该工艺可使垃圾渗滤液的COD值从1360 mg/L下降到93.6 mg/L,BOD5值从320 mg/L降低到28mg/L,NH3-N的值从1098.6 mg/L下降到16.1 mg/L,出水色度接近无色,处理效果良好.