贵州省都柳江砷污染事件的应急水技术与实施要点

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.     

城市给水厂应对突发性水源水质污染技术措施的思考

城市给水厂供水的水质安全十分重要。为了防范可能发生的水源水质突发性污染的威胁,保证供水水质,应考虑给水厂应急供水的技术措施。分析表明,各种药剂投加方法及设施能解决多数污染物的应急控制问题,而且投资小,启动迅速,应作为给水厂应对突发污染的首选措施。给水厂应急方案中还应重视“关口前移”、应急排水、强化混凝等宝贵经验。     

农村饮水工程适宜水质净化技术

农村饮水工程根据不同的原水水质条件，宜采用不同的水质净化技术。对地表水浑浊度长年低于20NTU、瞬间不超过60NTU原水，可采用微絮凝直接过滤加消毒或慢滤加消毒净化工艺；浑浊度长年低于500NTU、瞬间不超过1000NTU的原水，采用混凝沉淀（澄清）过滤、消毒的常规净水工艺。对于特殊水质如氟超标的地下水、砷超标的地下水、苦咸水及其他污染水，根据不同情况，可分别采用活性氧化铝吸附法、混凝沉淀法、多介质过滤法、铁盐混凝沉淀法、电渗析法、反渗透法等不同方式予以处理。     

炭砂滤池吸附工艺生产运行研究

对清泰水厂改造工程中采用的炭砂滤池吸附净水工艺进行水质分析和生产运行研究,积累运行管理经验。混凝—沉淀—炭砂过滤—消毒工艺出水水质能满足国标水质要求,特别是对有机物和氨氮的去除效果优于常规工艺,但在浊度控制上与发达国家水质要求和集团内控指标要求尚有一定差距,需设置后续工艺进一步处理。炭砂滤池宜设计成完全避光型式,宜控制炭砂滤池进水浊度在1～2NTU,应定期检查和维护炭砂滤池以确保正常运行。在受潮汐影响河流取水的水厂采用预臭氧工艺时,宜保留预氯化投加点,在沙蚕繁殖季节需少量持续加氯进行杀灭处理。     

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。     

高铁酸钾预氧化处理微污染原水的效能

综述高铁酸钾预氧化处理微污染原水具有氧化去除有机物、强化混凝、控制致突变物、除藻、消毒、控制消毒副产物、除砷等多种效能。指出高铁酸钾预氧化处理微污染原水可以极大提高处理效果，缓解目前水质性缺水的危机；对今后的研究方向提出了建议。     

基于常规处理工艺水中铊污染应急处理研究

由于湘江水体出现铊含量超过《地表水环境质量标准》(GB 3838-2002)规定限值0.0001mg/L的现象,以湘江为水源的自来水厂供水安全受到威胁.为了保障供水水质安全,在株洲市某水厂进行了一系列的生产性试验,发现预氯化+强化混凝的方法对水中铊有较好的处理效果.结果 表明:通过增加预处理加氯量,将沉淀出水余氯控制在...     

以北江某水厂为例讨论水源污染的应急措施

以北江某水厂为例,讨论在常规工艺处理的基础上,通过分析历年水源水质数据,逐步建立针对浊度、氨氮等水源持续性污染时水厂的应对措施;制定突发污染事件应急预案和应急机制,应对水源突发性污染,保证供水水质安全达标。     

汶川地震对城市给水系统设计及应急启迪

震后应急供水对于促进社会稳定及满足人民基本生活需求非常重要。由于缺乏应急供水水质及水量标准,未考虑地震等重大自然灾害后居民用水特点,基于同一标准规划和设计的给水管网,震损点多、漏失量大、压力低、水质污染概率高,使得应急恢复供水缺乏指导性、难度大和风险性高。结合重灾区震后应急供水面临的困难,对管网规划思路、水厂药剂安全储量、水质应急监测、水厂应急处理技术措施提出了建议。     

县级水厂特发性异常水质的应急处理预案

针对县级水厂原水取水口特发性的污染事故,水厂制水过程中出现的异常水质问题,供水管网出现的异常水质问题,逐一分析产生原因,排查问题及探讨应急处理预案.     

荷兰地下水中的砷对饮用水供给的影响

介绍了荷兰饮用水的供给状况,地下水中砷的分布,饮用水中的砷,以及8个典型水文系统中砷的形成过程、水化学特征,分析了荷兰地下水中砷的活动过程,主要包括:吸附和阴离子交换、黄铁矿的氧化反应和氧(氢氧)化铁的还原性溶解以及砷酸盐被还原成亚砷酸盐,并针对不同的情况提出了相应的治理措施。     

Geospeciation of arsenic using MINTEQA2 for a post-mining lake.

The objective of this study was to investigate the cycling of arsenic in the water column of a post-mining lake. This study is part of a research project to develop health risk assessment for the surrounding population. Inductively Coupled Plasma-Mass Spectrophotometer (ICP-MS) and Capillary Electrophoresis (CE) have been used to analyze the total amount and speciation, respectively. A computer program, called MINTEOA2, which was developed by the United States Environmental Protection Agency (USEPA) was used for predicting arsenic, iron, and manganese as functions of pH and solubility. Studying the pH values and cycle of arsenic shows that the percentage of bound arsenate, As(V) species in the form of HAsO4- increases with range pH from 5 to 7, as well as Fe(II) and Mn(III). As expected phases of arsenic oxides are FeAsO4 and Mn3(AsO4), as a function of solubility, however none of these phases are over saturated and not precipitated. It means that the phases of arsenic oxides have a high solubility.     

Removal of arsenic from groundwater by arsenite-oxidizing bacteria

The presence of arsenic in groundwater has been of great public concern because of its high toxicity. For purification of arsenic-contaminated groundwater, bacterial oxidation of arsenite, As(III), with a chemical adsorption process was examined in this study. After As(III) oxidation to arsenate, As(V), arsenic is easily removable from contaminated groundwater because As(V) is more adsorptive to absorbents than As(III). By acclimation to As(III) of high concentrations, a mixed culture of heterotrophic bacteria with high As(III)-oxidizing activity was obtained from a soil sample that was free from contamination. With initial concentration up to 1,500 mg l(-1) As(III), the mixed culture showed high As(III)-oxidizing activity at pH values of 7-10 and at temperatures of 25-35 degrees C. The mixed culture contained several genera of heterotrophic As(III)-oxidizing and arsenic-tolerant bacteria: Haemophilus, Micrococcus, and Bacillus. Activated alumina was added to the basal salt medium containing 75 mg l(-1) As(III) before and after bacterial oxidation. Arsenic removal by activated alumina was greatly enhanced by bacterial oxidation of As(III) to As(V). The isotherms of As(III) and As(V) onto activated alumina verified that bacterial As(III) oxidation is a helpful pretreatment process for the conventional adsorption process for arsenic removal.     

地下水砷污染防治试验研究

针对我国地下水砷污染及饮用水质健康风险问题,以地下水中砷这种特征污染物的净化及安全供水为研究目标,为了寻求治理地下水砷污染途径,提出了石英砂原位改性除砷的方法。采用化学沉淀法制备改性石英砂,在室内开展镀铁条件试验研究,确定注入试剂种类、注入方式、持续时间及强度等重要参数。进而,对改性石英砂进行了表面特征分析并开展了静态吸附试验和动态除砷试验。研究成果旨在为我国地下水污染控制和饮用水安全供给工程提供相关的技术支撑。     

Phosphate and arsenate retention in sediments of the Anllóns river (northwest Spain).

We have studied the distribution and sorption behavior of phosphate and arsenate in bed-sediments of the Anllóns river (NW Spain). As a consequence of the intense gold-mining activity in the past, substantial amounts of arsenic were found in the river sediments. For phosphorus, higher concentrations were found near two sources of P pollution. Sorption isotherms were described by the Freundlich, Langmuir and Tempkin equations. In general, the sediments sorbed more P than As. The equilibrium P concentration (EPC) reveals that sediments act as a scavenger for soluble P; by contrast, equilibrium As concentration (EAC) values were high for the As-rich sediments and correlates well with total arsenic content. Amorphous Fe oxides content, organic matter and fraction of clay plus silt were the main properties of the sediments related with the sorption of arsenate and phosphate. The results obtained provide a first estimate of the sorption behavior and availability of the phosphate and arsenate anions in the sediments of the Anllóns river.     

Effect of Fe3O4 nanoparticles on magnetic xerogel composites for enhanced removal of fluoride and arsenic from aqueous solution

Fe₃O₄ magnetic xerogel composites were prepared by polycondensation of resorcinol (R)–formaldehyde reaction via a sol–gel process in an aqueous solution through varying the molar ratio of Fe₃O₄ nanoparticles (MNPs), catalyst (C), and water (W) content. MNPs were obtained by co-precipitation (MC), oxidation of iron salts (MO), or solvothermal synthesis (MS). Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system. The MC-based MNPs had higher adsorption capacities for both fluoride (202.9 mg/g) and arsenic (3.2 mg/g) than other MNPs in optimum conditions. The X-ray diffraction, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%–4.42% of Fe with a molar ratio of MNPs (M) to R between 0.01 and 0.10. With low R/C and optimum M/R ratios, an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities. The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio (100) and at different R/W (0.05–0.06) and M/R (0.07–0.10) ratios had a high arsenic removal efficiency of 100% at an As(V) concentration of 0.1 mg/L and pH of 3.0. The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites. Therefore, Fe₃O₄ nanoparticles enhanced the adsorption of arsenate and fluoride. The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.     

延庆县水务一体化管理的实践与探索

延庆县政府于2005年1月组建了延庆县水务局,作为县政府水行政主管部门,综合水利、供水、排水三大行业,促进了水资源优化配置、合理开发、可持续利用,构建了大水务格局,解决了政出多门的问题,为延庆经济社会的发展提供了可靠的水务保障。     

Arsenic contamination of groundwater in Nawabganj, Bangladesh, focusing on the relationship with other metals and ions.

Serious arsenic contamination of groundwater in Bangladesh has been frequently reported and is of great concern. In this research, repeated water sampling from the same 10 tubewells in Nawabganj municipality, Bangladesh, was conducted and analysed, focusing on the seasonal variation of water quality and the relationship among arsenic and other metals and ions. For the seasonal variation of water quality, arsenic and iron concentrations were higher in the rainy season in general although the tendency was not consistent and it depended on the tubewell and the time. Correlation between arsenic and iron could not be observed in this study (r = -0.01) when using all cases. This was because no correlation was observed in the higher arsenic concentration range. Arsenic removal by co-precipitation with coexisting iron is known as one of the locally applicable techniques in Bangladesh, but the result from this study suggests that some additional treatments such as the extra injection of iron should be performed in some cases, especially where the arsenic concentration is high. The correlation between arsenic and other substances was also analysed. As a result, manganese (r = 0.37), molybdenum (r = 0.33) and sulfate ion (r = -0.33) significantly correlated with arsenic (p < 0.05). The negative correlation between arsenic and sulfate ion implies the dissolution of arsenic into groundwater under reductive conditions although there are some exceptional cases.     

鲁北平原养鸡场周边包气带与地下水砷化合物分布规律

洛克沙胂(3-硝基-4-羟基苯胂酸)被广泛用作饲料添加剂,但大部分以原体形式随粪便排出,进入环境的洛克沙胂在微生物和光照作用下最终转化为毒性较大的As(V)和As(III)等,并在雨水或农灌的淋滤冲积下污染周边土壤、地表水和地下水。以鲁北平原某养鸡场为研究区,对鸡粪、饲料、周边表层土壤、鸡粪堆积和背景包气带垂向剖面以及地下水进行洛克沙胂及其代谢物的检测,结果饲料中洛克沙胂浓度为34mg/kg,鸡粪中HAPA(3-氨基-4-羟基苯胂酸)浓度为11 mg/kg,距离鸡场越近的表层土壤砷含量越高。三个包气带垂向剖面均以As(V)为主,As(III)含量较小。鸡粪堆积处垂向剖面上HAPA、As(V)和As(III)在土壤表层含量最高,浓度随深度增加而呈下降趋势,同时受到土壤岩性的影响,砷化合物主要的吸附层位为0~30cm与200cm以下;背景包气带垂向剖面上各砷化合物含量均明显低于鸡粪堆积处包气带垂向剖面的砷化合物含量;在鸡场内旧井中检测到浓度为165μg/kg的As(V)。结果证实鸡粪堆积导致土壤包气带、周边土壤和地下水砷含量增加,且这种污染很难消除。     

Spatial variation of health risk of groundwater for drinking water supply in Mingshan County, Ya'an City, China

Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya'an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency (U.S. EPA). Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation (IDW) and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6+, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.