Effect of typhoon with extreme precipitation on mountain reservoir drinking water treatment: a case study in Ningbo, China

Due to frequent drinking water pollution accidents in the past decade, it is common that mountain reservoirs were used as the source of drinking water in China. However, some coastal areas frequently suffer from typhoon with extreme precipitation, which results in the water quality deterioration of the reservoirs. The influence of typhoons with extreme precipitation on Jiaokou reservoir and the emergency treatment process of Maojiaping water treatment plant in the past three typical typhoons with extreme precipitation from the year of 2012-2015 were studied. It was found that the degradation of water quality, such as the increase of turbidity and bacteria index, may not merely appear during the events, but last for several days. Changing the dosage of water purification agent, such as coagulant and disinfectant at right time and place may be an efficient emergency water treatment process. Based on the analysis of water quality variation rule during and after the events, it was also found that emergency treatment can be fully prepared before the arrival of a typhoon with extreme precipitation. And in order to better respond to the typhoon with extreme precipitation, several suggestions are also proposed in this paper as follows: establishing vegetated buffers at right place, such as macrophanerophytes,shrub or herbage, increasing investments in infrastructure management, merging or cancelling the small-scale water treatment plants, preparing adequate water purification agent before the typhoon comes, etc.

Drinking water safety and the development of purification technology

This paper briefly introduced the evolution of purification technology for drinking water over time. After description of the 1st generation processes in the beginning of the 20th century - conventional processes and the 2nd generation processes in 1970s - advanced treatment processes, a tertiary processes - UF (ultrafiltration) based on integrated processes was proposed. Moreover, reaction measures (dosing variety of regents for different contaminants) for urban source water emergencies were illustrated in brief. A new technology of KMnO4 and potassium permanganate composite (PPC) for drinking water purification which was developed by Harbin Institute of Technology (HIT) was concisely introduced.

The Public Water Supply Protection Value of Forests: A Watershed-Scale Ecosystem Services Analysis Based upon Total Organic Carbon

We developed a cost-based methodology to assess the value of forested watersheds to improve water quality in public water supplies. The developed methodology is applicable to other source watersheds to determine ecosystem services for water quality. We assess the value of forest land for source water mitigation of total organic carbon (TOC) through the use of linked watershed and reservoir simulation models and cost-based valuation economics. Watershed modeling results indicated that expected urbanization will increase TOC loads to Converse Reservoir (Mobile, AL). Reservoir model results indicated that future median TOC concentrations increased by 1.1 mg·L-1 between 1992 and 2020 at the source water intake. Depending upon dynamic reservoir TOC concentrations, additional drinking water treatment with powdered activated carbon (PAC) often is necessary between May and October to comply with Safe Drinking Water Act regulations. The cost for additional treatment was calculated using minimum and maximum volume treated with simulated TOC concentrations at the source water intake. Daily simulated TOC concentrations for the base scenario using 1992 land cover (3% urban) were compared with simulated TOC concentrations following forest to urban land conversion predicted in the watershed by 2020 (22% urban). The daily cost for additional drinking water treatment with PAC was calculated if simulated TOC concentrations exceeded 2.7 mg·L-1. The mean increase in daily treatment costs between base and future scenarios ranged from $91 to $95 per km2 per day for forest land water purification ecosystem services.

Presence, dissemination and removal of antibiotic resistant bacteria and antibiotic resistance genes in urban drinking water system: A review

Antibiotic resistance in aquatic environment has become an important pollution problem worldwide. In recent years, much attention was paid to antibiotic resistance in urban drinking water systems due to its close relationship with the biosafety of drinking water. This review was focused on the mechanisms of antibiotic resistance, as well as the presence, dissemination and removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the urban drinking water system. First, the presence of ARB and ARGs in the drinking water source was discussed. The variation of concentration of ARGs and ARB during coagulation, sedimentation and filtration process were provided subsequently, in which filtration was proved to be a promising technology to remove ARGs. However, biological activated carbon (BAC) process and drinking water distribution systems (DWDSs) could be incubators which promote the antibiotic resistance, due to the enrichment of ARGs and ARB in the biofilms attached to the active carbon and pipe wall. Besides, as for disinfection process, mechanisms of the inactivation of ARB and the promotion of conjugative transfer of ARGs under chlorine, ozone and UV disinfection were described in detail. Here we provide some theoretical support for future researches which aim at antibiotic resistance controlling in drinking water.

Emergency drinking water treatment in source water pollution incident—technology and practice in China

An investigation into emergency potable water treatment technologies was conducted to investigate China’s water pollution situation.In order to confirm optimum parameters,the technological efficiency of each pollutant was obtained.About 100 contaminants were tested to find the emergency treatment technologies,most of which were found to be positive.This paper presents the three largest and most significant water pollution incidents in China to date,analyzing cases such as the nitrobenzene pollution incident in the Songhua River in November 2005,the cadmium pollution incident in the Beijiang River in December 2005,and the water crisis with odorous tap water in Wuxi City in May 2007.

韧性城市建筑“平急结合”设计给排水应对关键措施探索

简介韧性城市建筑中适用于临时隔离收治点的建筑类型,提出建立临时隔离收治点“平急结合”设计的标准体系构想,解析作为临时隔离收治点的新建建筑、既有建筑在设计或改造中的给排水应对措施,重点就条件预留、用水定额、系统定型、管道布设、设备选用、污水处理等方面进行深入探索。

Applying chemical sedimentation process in drinking water treatment plant to address the emergent arsenic spills in water sources

Arsenic （As） spills and sometimes polluted water occurred more frequently sources in recent years in China. It is as urgent need to develop emergency treatment technologies to address the arsenic threat for large-scale water treatment plants. In response, we developed a chemical sedimentation technology to remove arsenic contaminants for water treatment plants. Bench-scale experiments were conducted to investigate the efficiency of arsenic removal and the influencing factors of the chemical sedimentation treatment process. The influencing factors included the choice and dosage of coagulants, the valence of arsenic and pH value of solution. The As（V） contaminants can be almost completely removed by ferric or alum coagulants. The As（III） contaminants are more recalcitrant to chemical sedimentation, 75% for ferric coagulant and 40% for alum coagulant. The quantitative results of arsenic removal load by different ferric or alum coagulants were presented to help determine the parameters for arsenic treatment technology. The dominant mechanism for arsenic removal is static combination, or adsorption of negative arsenic species onto positive ferric hydroxide or alum hydroxide flocs. The efficiency of this treatment technology has also been demonstrated by a real production test in one water treatment plant with arsenicrich source water and one emergency response. This technology was verified to be quick to set-up, easy to operate and highly efficient even for high concentration of arsenic.

六氯苯污染源水的饮用水应急处理工艺研究

针对长江水源地可能发生的六氯苯(HCB)突发污染事故,开展了应急处理工艺研究.考察了混凝剂聚合硫酸铁(PFS)投加量、KMnO4预氧化和木质粉末活性炭(PAC)吸附预处理对HCB去除效果的影响.根据静态试验,设计了三因素三水平正交试验,进一步考察了KMnO4氧化与PAC吸附联用预处理-混凝沉淀工艺去除HCB的效果.结果表明,常规处理无法有效去除HCB;单独KMnO4预氧化无法明显改善混凝沉淀对HCB的去除效果;PAC联用吸附预处理可明显提高去除效率.正交试验结果表明,在PAC,PFS,KMnO4投加量分别为40,5.0,0.5mg/L的最佳条件下,HCB去除率为98.97%,但浊度在2NTU以上.选取PAC吸附预处理-混凝沉淀工艺进行中试试验,结果表明,在PFS和PAC投加量分别为15mg/L和40mg/L时,HCB的去除率在98%以上,HCB剩余浓度和浊度分别在1μg/L和1NTU以下.

强电离放电等离子体在应急净化饮用水中的应用

为解决常规等离子体水处理技术中存在的处理时间长、处理量有限等问题,促进等离子体技术在饮用水应急净化领域的应用,研究了基于微流注与微辉光的强电离放电快速水处理技术。实验利用大气压强电离放电协同水力空化技术,在水中产生高浓度活性氧自由基,进行水中大肠杆菌的杀灭剂效、时效关系研究,同时研究了不同水质水源水的灭菌效果和水质改善情况。结果表明,当强电离放电功率为120~130 W、空化进气体积流量为0.1 L/min时,可100%杀灭水中l04~106 mL^(–1)的大肠杆菌,消耗的活性氧自由基体积质量为0.5~0.7 mg/L,灭菌时间仅需3~10 s;当放电功率为140~160 W、活性氧自由基体积质量为0.8~1.2 mg/L时,处理水库水源水中的微生物指标低于国家《生活饮用水卫生标准》限值,水体色度降至15度以下,水中有机物含量(UV254)去除率达68%~76%,且未检出甲醛等氧化消毒副产物,处理结果符合应急情况下饮用水的消毒净化要求。此外,强电离放电等离子体可在水中高效生成体积质量>8 mg/L的活性氧自由基,能满足大流量水体的快速消毒净化需求。上述研究结果可为放电等离子体在饮用水应急消毒、医疗废水净化处理等领域的应用研究提供重要基础。

饮用水应急除镉净水技术与广西龙江河突发环境事件应急处置

对饮用水应急除镉技术和2012年广西龙江河突发环境事件应急处置进行了技术总结。首先归纳了应急除镉的技术原理、工艺控制条件和实施要点,然后概括介绍了有关龙江河突发环境事件,对其应急处置的措施和效果进行了全面总结。在此次事件中,通过采取河道投药进行弱碱性化学法沉镉处置和下游汇流调水稀释的措施,实现了把含镉污染水团控制在龙江河河段范围内、下游柳江镉浓度不超标的控制目标要求。对于河道沉镉处置可能产生的环境影响做了详细说明,并总结了环境后评估的初步结果。在龙江河突发环境事件中除了最严重的镉污染外,还含有砷、铊、锑等多种污染物,自来水厂应急处理的难度极大。在水专项应急处理课题研究的基础上,通过采取针对性措施,实现了下游柳州自来水厂出水的全面达标,保障了供水安全。

饮用水源突发挥发酚污染应急处理中试研究

通过为期2个月规模为4m3·h-1的中试试验,考察了常规给水工艺(混凝、沉淀和过滤)对突发挥发酚污染原水的处理情况,重点考察了活性炭吸附、臭氧预氧化和高锰酸钾预氧化等3种应急工艺的除酚效能.结果表明,常规混凝沉淀对挥发酚的去除率低于10%,砂滤在12h内可起到拦截挥发酚的作用.3种应急工艺均可提高挥发酚的去除效果,起到应急的作用.其中活性炭吸附对挥发酚的去除率可达44%;在0.5mg·L-1的投量下高锰酸钾预氧化可达到50%的除酚效率;臭氧预氧化可使沉淀出水挥发酚达标(0.002mg·L-1),挥发酚去除率约99%.

无锡自来水事件的城市供水应急除臭处理技术

2007年5月28日起,无锡市自来水南泉水源地的水质突然恶化,造成自来水臭味严重。经水质分析,产生臭味的物质是硫醇、硫醚类化合物,其中的主要致臭组分是甲硫醇。根据此类化合物易被氧化、不易被吸附的特性,应急处理采用了在取水口投加高锰酸钾,再在净水厂内絮凝池前投加粉末活性炭的应急处理工艺。取水口投加的高锰酸钾可以在输水过程中氧化可氧化的致臭物质和污染物,水厂内投加的粉末活性炭可以吸附水中可吸附的其他臭味物质和污染物,并分解可能残余的高锰酸钾。高锰酸钾和粉末活性炭的投加量根据水源水质情况和运行工况进行调整,并逐步实现了关键运行参数的在线实时检测和运行工况的动态调控。在应急处理措施实施后,自来水臭味问题立即消除。后经自来水监测部门和卫生监督部门对出厂水的多次检验,水质达到新国标《生活饮用水卫生标准》的要求,毒理学项目全部合格,无锡市从6月4日起宣布恢复正常市政供水。以上应急处理技术成功应对了本次无锡水污染事件,并为应对类似的水污染突发事件提供了经验。

饮用水系统中药物和个人护理用品的研究进展

药物和个人护理用品(pharmaceuticals and personal care products,PPCPs)作为一类新兴的有机污染物备受研究者的关注,未被去除的PPCPs母体或转化/降解产物可能进入饮用水系统,威胁人体健康.本文分析了PPCPs在饮用水源、出厂水、供水管网和龙头水中的赋存状况,总结了饮用水厂各处理工艺对PPCPs的去除效果.PPCPs在饮用水系统中的浓度较低,一般在ng·L^(-1)到μg·L^(-1).饮用水厂处理工艺能有效去除特定PPCPs,其中氧化、活性炭及膜处理等深度处理工艺对PPCPs去除效果较好.加强对饮用水系统中PPCPs的来源控制、过程管理和末端监督等是将来的重要研究方向.

自来水厂应急除锰净水技术研究

2012年11月贵州省铜仁市万山特区发生了锰矿尾渣库管涌泄漏事件，导致下游锦江河的河水受到锰污染，威胁沿岸居民饮用水安全。总结了自来水厂应对水源突发锰污染事件的应急处理技术与工艺，即高锰酸钾预氧化工艺。突发污染事故进入水体的锰主要以溶解态二价锰的形式存在，可在自来水厂中投加高锰酸钾氧化剂，经氧化形成二氧化锰难溶沉淀物，再在混凝一沉淀一过滤过程中随矾花去除。现场试验研究显示，高锰酸钾预氧化除锰工艺至少可应对50倍锰超标原水，应急处理后出水锰浓度可稳定在0．02mg／L左右，满足《生活饮用水卫生标准》（GB5749--2006）对锰的浓度限值要求（不大于0．1mg／L）。在试验原水水质条件下，高锰酸钾与原水中锰浓度的最佳投加质量比为1．5～1．7，略低于理论质量比（1．915），可能原因是反应生成的二氧化锰可吸附去除部分锰离子，减少了高锰酸钾消耗量。在运行中按此最佳投加比控制可以取得很好处理效果，并有利于避免高锰酸钾投加过量。

饮用水源地突发苯酚污染的应急处理中试研究

以黄浦江饮用水源地取水口突发苯酚污染的应急处理技术研究为背景,模拟黄浦江边某原水厂的工艺建立中试装置,分别采用高锰酸钾氧化、活性炭吸附及活性炭吸附与高锰酸钾氧化联用技术对突发苯酚污染进行消减试验研究。针对不同的苯酚污染程度,确定了适宜的工艺和相应的药剂投加量。结果表明,当原水中苯酚质量浓度低于50μg.L-1时,只需在原水厂前池投加适量的高锰酸钾或活性炭,即可使苯酚消减至超标倍数在10倍以下。当原水中苯酚质量浓度在50～500μg.L-1时,需采用活性炭吸附与高锰酸钾氧化联用技术使酚消减,在前池投加10～50mg.L-1活性炭,同时在调压池投加2 mg.L-1高锰酸钾,可使出水苯酚超标倍数低于25倍。当原水中苯酚质量浓度趋于或超过500μg.L-1时,在前池投加50 mg.L-1活性炭,同时在调压池投加2 mg.L-1高锰酸钾,出水苯酚超标倍数仍在25倍以上。

2006年中国城市饮用水源突发污染事件统计及分析

统计分析了我国2006年1月1日至12月31日发生的城市饮用水源突发污染事件,以揭示2005年松花江污染和哈尔滨停水重大事件之后,中国城市水源突发污染事件发生的规律、危害、应急响应状况以及总体情况和变化趋势,检验近1年来中国城市水源突发污染事件应急机制的有效性和科学性。从发生日期、地点、污染物种类、事件简况、应急反应5个方面对75起突发污染事件的统计分析表明:1) 2006年突发污染事件总体呈数量增多、危害增大的趋势;2)危险化学品和各类工业污水仍是主要污染物;3)交通事故、工厂泄漏事故和突然排污仍是主要风险源;4)41.3%的事件威胁到了城市供水系统安全运行,造成城市几小时或多天停水,带来严重的社会影响;5)92%的突发污染事件得到了应急响直,但应急时间远大于国家规定的1h,应急预案在快速性和有效性方面还需改进。

贵州省都柳江砷污染事件的应急供水技术与实施要点

2007年12月底发生的贵州都柳江砷污染事件,造成下游三都县县城水厂被迫停水。清华大学张晓健教授及其课题组于2008年1月2日前往现场协助当地开展应急供水工作。应急处理采用了预氯化铁盐混凝法除砷净水工艺,先采用预氯化把水中可能存在的三价砷(亚砷酸)氧化成五价砷(砷酸氢根),再采用铁盐混凝剂混凝,用氢氧化铁絮体络合吸附砷酸根或是形成难溶的砷酸铁沉淀物,从而通过混凝沉淀过滤的净水过程进行除砷处理。经现场试验、设备改造、生产性运行调试和水质监测,应急除砷处理取得成功,出水达到《生活饮用水卫生标准》的水质要求,三都县县城水厂从1月6日15:00恢复正常供水,成为应对突发性砷污染的城市应急供水国内首次成功案例。

2007-2008年中国城乡饮用水源突发污染事件统计及分析

在文献[1,2]的基础上,通过查阅影响力较大的报刊和网站资料,统计了我国2007年1月1日至2008年12月31日期间发生的城乡饮用水源突发污染事件,分析了以2007年太湖蓝藻事件、2008年阳宗海污染事件为代表的近2年中国城乡水源突发污染事件及其应急情况的新特点从发生日期、地点、污染物种类、事件简况、应急反应5个方面对187起突发污染事件进行统计分析,研究表明:1)2007-2008年突发污染事件依然呈现数量增多、危害增大、风险源增多的趋势;2、各类工业污水和危险化学品仍是主要污染物;3)突然排污、交通事故、工厂泄漏仍是主要风险源,但是自然灾害(如冰冻灾害、地震)也能导致少数严重的突发污染;4) 43.3%的事件威胁到城市供水系统安全运行;5)75.9%的突发污染事件得到了应急响应,但响应时间仍然较长;6)大多数突发污染事件缺乏全面、客观、及时的信息披露与跟踪报道。

松花江和北江水污染事件中的城市供水应急处理技术

总结了近期在我国突发性水污染事件中所采用的城市供水应急处理技术。在松花江水污染事件中,采用了投加粉末活性炭和粒状活性炭过滤来吸附水中的硝基苯,其中在水厂取水口处投加粉末活性炭,把安全屏障前移是应急处理的关键措施。在广东北江镉污染事件中,紧急确定了弱碱性混凝处理的除镉技术,除镉处理的pH控制在9。经采用应急处理技术,在水源水中特征污染物超标数倍的情况下,水厂出水中污染物的浓度远远低于饮用水水质标准的限值,应急处理取得了成功。介绍了有关水污染事件的概况,总结了城市应急供水的应对措施和实施效果,并系统归纳了所用应急处理技术的要点,对全国城市供水应急系统的建设有重要的指导意义和参考价值。

饮用水安全保障技术

从饮用水安全保障的角度,综述目前国内外水厂常用的饮用水预处理技术、常规处理技术和深度处理技术,分析针对突发性水污染事件的饮用水应急处理技术和瓶装水生产企业中常用的纯净水处理技术,并展望几种极具应用前景的潜在处理技术。