Reduction of DOM fractions and their trihalomethane formation potential in surface river water by in-line coagulation with ceramic membrane filtration

This research was aimed at investigating the reduction of DOM fractions and their trihalomethane formation potential （THMFP） by in-line coagulation with 0.1 μm ceramic membrane filtration. The combination of ceramic membrane filtration with a coagulation process is an alternative technology which can be applied to enhance conventional coagulation processes in the field of water treatment and drinking water production. The Ping River water （high turbidity water） was selected as the raw surface water because it is currently the main raw water source for water supply production in the urban and rural areas of Chiang Mai Province. From the investigation, the results showed that the highest percent reductions of DOC, UV-254, and THMFP （47.6%, 71.0%, and 67.4%, respectively） were achieved from in-line coagulation with ceramic membrane filtration at polyaluminum chloride dosage 40 mg/L. Resin adsorption techniques were employed to characterize the DOM in raw surface water and filtered water. The results showed that the use of a ceramic membrane with in-line coagulation was able to most efficiently reduce the hydrophobic fraction （HPOA） （68.5%）, which was then followed by the hydrophilic fraction （HPIA） （49.3%）. The greater mass DOC reduction of these two fractions provided the highest THMFP reductions （55.1% and 37.2%, respectively）. Furthermore, the in-line coagulation with ceramic membrane filtration was able to reduce the hydrophobic （HPOB） fraction which is characterized by high reactivity toward THM formation. The percent reduction of mass DOC and THMFP of HPOB by in-line coagulation with ceramic membrane filtration was 45.9% and 48.0%, respectively.     

Emission factors of polycyclic aromatic hydrocarbons from domestic coal combustion in China

Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons （PAHs） are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4- ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.     

Effects of cathode potentials and nitrate concentrations on dissimilatory nitrate reductions by Pseudomonas alcaliphila in bioelectrochemical systems

The effects of cathode potentials and initial nitrate concentrations on nitrate reduction in bio- electrochemical systems （BESs） were reported. These factors could partition nitrate reduction between denitrification and dissimilatory nitrate reduction to ammonium （DNRA）. Pseudomonas alcaliphilastrain MBR utilized an electrode as the sole electron donor and nitrate as the sole electron acceptor. When the cathode potential was set from -0.3 to -I.1 V （vs. Ag/AgC1） at an initial nitrate concentration of 100 mg NO~-N/L, the DNRA electron recovery increased from （10.76 ± 1.6）% to （35.06 ± 0.99）%; the denitrification electron recovery decreased from （63.42 ± 1,32）% to （44.33 ± 1.92）%. When the initial nitrate concentration increased from （29.09 ± 0.24） to （490.97 ± 3.49） mg NO3-N/L at the same potential （-0.9 V）, denitrification electron recovery increased from （5.88 ± 1.08）% to （50.19 ±2.59）%; the DNRA electron recovery declined from （48.79 ±1.32）% to （16.02 ± 1.41）%. The prevalence of DNRA occurred at high ratios of electron donors to acceptors in the BESs and denitrification prevailed against DNRA under a lower ratio of electron donors to acceptors. These results had a potential application value of regulating the transformation of nitrate to N2 or ammonium in BESs for nitrate removal.     

中山市不同类型企业周边土壤重金属污染特性及潜在生态风险评价

以中山市不同类型涉重金属企业周边土壤(0~20cm)为调查对象,分析了土壤中重金属Cu、Zn、Pb、Cd、Cr、Hg和As的含量,采用地积累指数法和潜在生态危害指数法对土壤重金属污染进行了分析和评价。结果表明,除Pb外其它7种元素含量超过广东省背景值,不同类型土壤环境的污染程度地积累指数评价处于无-中度污染,潜在生态危害处于强度危害程度。统计分析表明,Cr、Ni、Cu、Zn具有显著相关性,不同类型企业周边土壤中重金属污染主要受Cr、Cu、Ni、Zn控制,其次是受As、Hg和Cd控制。     

安徽省垃圾填埋气CO_2减排潜力研究

采用IPCC与可生物降解两种预测模型对安徽省2020年城市生活垃圾填埋气甲烷产量进行预测,并分析比较模型预测结果;进而通过填埋气发电项目对安徽省垃圾填埋气二氧化碳减排潜力进行探讨。结果表明:预计到2020年,安徽总的生活垃圾清运量可达到758.9万吨,可产生的生活垃圾填埋气甲烷产量约45.5万吨,若这些甲烷气体不经处理直接排放到大气中,相当于排放约900万吨的CO2,因此,安徽省垃圾填埋气CO2减排潜力巨大,其基于清洁发展机制(CDM)的减排潜力可达1.46×109吨。该研究对促进安徽省CDM项目的开发,充分利用CDM资金促进安徽经济的可持续、健康发展具有一定的指导意义。     

成都市大气环境VOCs污染特征及其健康风险评价

于2012年9月,在成都市分别选取代表城市大气环境和路边大气环境的两个采样点对大气中挥发性有机物(VOCs)进行采样,对不同大气环境中VOCs的浓度水平与变化特征、组成和反应活性进行分析,并对其中的芳香烃化合物进行健康风险评价.结果表明,成都市城市大气环境和路边大气环境中TVOCs的平均质量浓度分别为(108.57±52.43)μg·m~(-3)和(132.61±49.31)μg·m~(-3),不同大气环境中各烃类物质浓度均呈现出烷烃芳香烃烯烃炔烃的趋势;城市和路边大气环境中芳香烃和烯烃对臭氧生成潜势(OFP)贡献较大,关键物种均为间/对二甲苯、甲苯、乙烯、邻二甲苯和丙烯;不同大气环境中的苯、甲苯、乙苯和二甲苯(BTEX)对人体的非致癌风险和危害指数均小于1,对暴露人群不存在非致癌风险;致癌物质苯对人体的致癌风险高于安全阈值1.00E-06,对暴露人群可能存在致癌风险.     

南京地区大气PM2.5潜在污染源硫碳同位素组成特征

基于南京地区大气PM_(2.5)潜在污染源,采用EA-IRMS技术分别测定了样品中硫碳同位素组成,并分析不同污染源之间的关联性.结果表明,南京地区煤炭烟灰δ~(34)S值范围为1.8‰~3.7‰,δ~(13)C值范围为-25.50‰~-23.57‰;机动车尾气δ~(34)S值范围为4.6‰~9.7‰,δ~(13)C值范围为-26.32‰~-23.57‰;生物质烟灰δ~(34)S值范围为5.2‰~9.9‰,δ~(13)C值范围为-19.30‰~-30.42‰;扬尘δ~(13)C值为-13.45‰.南京地区煤炭烟灰颗粒物的硫同位素较轻,扬尘的碳同位素较重.对比国内外不同污染源δ~(34)S与δ~(13)C值,南京地区大气PM_(2.5)中的潜在污染源的δ~(34)S与δ~(13)C具有明显的区域性.因此,潜在污染源的δ~(34)S、δ~(13)C值可为南京地区大气PM_(2.5)的源解析提供同位素组成源谱支持.     

2013年12月中国中东部地区严重灰霾期间上海市颗粒物的输送途径及潜在源区贡献分析

2013年12月初中国中东部地区发生了入冬以来最为严重的一次长时间、大范围的高浓度颗粒物污染过程,期间上海市PM10小时浓度最大值超过700μg·m-3,PM2.5最大小时浓度超过600μg·m-3.为研究此次严重灰霾污染期间影响上海的污染气团的主要传输途径,采用HYSPLIT后向轨迹结合聚类分析方法,探讨了本次污染事件中到达上海的主要气团轨迹,结合上海城区在线观测的PM10小时浓度资料,通过计算潜在源贡献因子PSCF和浓度权重轨迹CWT,分析了影响上海2013年12月PM10质量浓度的潜在源区,并探讨了不同源区对上海市PM10质量浓度贡献的差异.结果表明,西北路径和北路径是污染事件中的主要输送通道,在到达上海的气团轨迹中,大陆气团和海洋气团分别占总轨迹的79.6%和20.4%,影响上海的潜在源区除长三角一带的江苏、浙江和安徽等人口密集,工业、重工业和交通污染严重的地区以外,山东、河北、河南等地对于上海城区颗粒物污染亦有一定贡献.研究表明,区域大气污染联防联控乃至跨区域联动对于应对当前频发的重污染态势具有极为重要的意义.     

大伙房水库上游重点矿区污染及其潜在生态危害评价

对大伙房水库上游3个重点矿区尾矿渣及周边土壤表层的重金属及氰化物进行了分析,采用Hakanson潜在生态危害指数法对其生态危害程度进行评价。结果表明,铜矿（A）属重度生态危害,金矿（C）、铁矿（B）属低生态危害。     

遵义松林Ni-Mo矿区耕地土壤铊污染及潜在生态风险初步评价

贵州遵义松林Ni-Mo矿区为华南下寒武统黑色页岩Ni-Mo矿化带中的典型矿区之一,对由其矿产资源开采活动引起的土壤环境质量评价具有重要的科学及实际意义。本研究以遵义松林Ni-Mo矿区耕地土壤为研究对象,采用ICP-MS分析土壤中铊的含量。分析结果显示,矿区耕地土壤中铊平均含量为1.84mg/kg,明显高于贵州土壤表层铊元素背景值,初步认为矿区黑色页岩、Ni-Mo矿体、开采暴露于地表的尾矿及围岩碎石为矿区耕地土壤铊的来源。运用地质累积指数和潜在生态危害指数分别对耕地土壤铊污染程度和潜在生态风险进行了初步评价,结果表明:研究区耕地土壤已遭受铊污染,其污染程度评价等级可达中度-重污染;部分样品的潜在生态风险评价等级为中等,显示该区耕地土壤存在潜在生态风险,值得开展进一步的土壤铊污染修复研究。