大连市饮用水中多环芳烃的概率致癌风险评价

饮用水中多环芳烃(PAHs)的水平及其致癌风险直接关系到居民的身体健康.考察了大连市饮用水中14种典型PAHs的质量浓度,并应用概率致癌风险分析方法评价饮用水中PAHs对不同年龄段和性别人群的致癌风险.结果表明:饮用水中基于苯并(a)芘的毒性当量为3.6 ng/L,低于国家饮用水标准.对儿童和青年,饮用水中PAHs引起的累积概率为90%的致癌风险分别为6.2×10-7和7.4 ×10-7,低于美国环保局建议的致癌风险值10-6,且性别间的差异很小;对成年人,累积概率为90%的致癌风险为1.7×10-6,饮用水中PAHs对成年人具有潜在的致癌风险,并且女性大于男性.同时分析了影响概率致癌风险评价的主要因素,其中饮用水中PAHs毒性当量的变化对致癌风险评价结果影响最大.     

TiO2晶须在深度净化饮用水过程中失活原因分析

研究了TiO₂晶须在光催化深度净化饮用水过程中失活的原因及相应的再生方法.对TiO₂薄膜失活前后的AFM、XRD表征,以及对失活前后TiO₂晶须酸洗液的ICP分析表明,TiO₂晶须失活的主要原因是难溶性碳酸钙在催化剂表面的沉积.由于自来水中钙离子的存在以及有机物光催化降解过程中产生的二氧化碳,生成的难溶性碳酸钙覆盖在催化剂的表面,影响了紫外光的透光率,限制了光生电子和光生空穴的生成,导致催化剂的光催化能力逐渐下降直至失活;失活的催化剂通过1 mol/L的盐酸酸洗4　h后,光催化活性可以恢复到95%左右;多次失活/再生的催化剂的光催化活性保持较好的稳定性.     

超滤去除水中内分泌干扰物（BPA）的效果和影响因素

采用终端超滤工艺去除饮用水中内分泌干扰物双酚A（BPA）,主要考察了BPA初始浓度、膜截留相对分子质量、pH、离子强度和有机物对BPA去除效果的影响.结果表明,超滤对饮用水中BPA具有良好的去除效果.当BPA的初始浓度在100～600μg/L范围内,截留相对分子质量2?000～10?000的超滤膜对BPA的去除率均在92.0%以上.溶液的pH值接近BPA的pK_a（9.6～11.3）时,BPA去除率明显降低.离子强度对去除率的影响较小.溶液中的腐殖酸对超滤去除BPA的影响较小.试验证实,吸附是超滤去除疏水性BPA分子的主要机理.     

保护环境"十二五"再起航

日前,环境保护部副部长李干杰在国务院新闻办举行的新闻发布会上介绍了我国2010年的整体环境状况,并通报了十二五期间我国环境所面临的问题以及环保部在围绕环境质量改善方面将要采取的措施。他表示,十二五期间我国面临着十分严峻的环境保护形势,主要体现为我国产业结构、     

稳步推进着力构建国家生态安全屏障——《青藏高原区域生态建设与环境保护规划(2011-2030年)》解读

今年5月,国务院印发了《青藏高原区域生态建设与环境保护规划(2011—2030年)》(以下简称《规划》)。《规划》是青藏高原区域生态建设与环境保护的纲领性文件,是《国民经济和社会发展第十二个五年规划纲要》和中央第五次西藏工作座谈会总体部署的具体化,对于调动一切积极因素,扎实做好当前和未来一段时     

整治带来哪些直接利益?

富阳市通过开展造纸行业专项整治,实现了江南片造纸企业供水、供电、供汽、治污四个统一,区域环境质量持续稳定优良.富阳市境内一江十溪、饮用水水源地与城市内河各水体水质总体保持稳定,4个集中式饮用水     

利用生物燃料电池进行海水淡化

据估计,未来20年内,人均清洁水供应量将平均减少三分之一.海水淡化是从世界多个地区的微咸水和海水中生产可饮用水的一种选择,但大多数海水淡化技术高耗能且高费用.目前采用的海水淡化技术主要是反渗透、电渗析和蒸馏.海水淡化过程的不断改进,特别是在过去的10年里,已经使得这些系统更加可靠,减少资金成本,但高能源需求     

Effects of advanced oxidation pretreatment on residual aluminum control in high humic acid water purification

Due to the formation of disinfection by-products and high concentrations of Al residue in drinking water purification, humic substances are a major component of organic matter in natural waters and have therefore received a great deal of attention in recent years. We investigated the effects of advanced oxidation pretreatment methods usually applied for removing dissolved organic matters on residual Al control. Results showed that the presence of humic acid increased residual Al concentration notably. With 15 mg/L of humic acid in raw water, the concentrations of soluble aluminum and total aluminum in the treated water were close to the quantity of Al addition. After increasing coagulant dosage from 12 to 120 mg/L, the total-Al in the treated water was controlled to below 0.2 mg/L. Purification systems with ozonation, chlorination, or potassium permanganate oxidation pretreatment units had little effects on residual Al control; while UV radiation decreased Al concentration notably. Combined with ozonation, the effects of UV radiation were enhanced. Optimal dosages were 0.5 mg O3/mg C and 3 hr for raw water with 15 mg/L of humic acid. Under UV light radiation, the combined forces or bonds that existed among humic acid molecules were destroyed; adsorption sites increased positively with radiation time, which promoted adsorption of humic acid onto polymeric aluminum and Al(OH)3(s). This work provides a new solution for humic acid coagulation and residual Al control for raw water with humic acid purification.     

Development of systems for detection, early warning, and control of pipeline leakage in drinking water distribution: A case study

The integrated system for the detection, early warning, and control of pipeline leakage has been successfully developed to manage the pipeline networks of Beijing.     

Treatment of taste and odor causing compounds 2-methyl isoborneol and geosmin in drinking water: A critical review

Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds – 2-methyl isoborneol (MIB) and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed alongwith the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a fullscale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ine ective for removal of MIB/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be e ective in treatment of these two compounds. Although some of these technologies are more e ective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and e ectiveness of the treatment system.