BIODEGRADATION OF DISINFECTION BYPRODUCTS AS A POTENTIAL REMOVAL PROCESS DURING AQUIFER STORAGE RECOVERY1

ABSTRACT: The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water.     

自来水二氧化氯消毒控制三氯甲烷研究

对自来水二氧化氯消毒控制三氯甲烷形成进行了试验研究 ,二氧化氯预消毒替代预氯化消毒可以降低水中的三氯甲烷 ,预消毒处理后形成三氯甲烷的反应受温度和反应时间的影响。使用二氧化氯与氯配制的混合消毒剂消毒时 ,随二氧化氯含量增加 ,水中的三氯甲烷将明显减少。     

pH对电化学氧化垃圾渗滤液的影响

主要研究了不同pH值对高氨氮垃圾渗滤液的电化学氧化的影响,重点考察了pH值在电解过程中的电解速率、电流效率、能耗以及三氯甲烷生成情况。结果表明:pH对电化学氧化垃圾渗滤液过程有重要的影响。在弱碱性条件下,电解垃圾渗滤液过程中氨氮及COD的降解速率、电流效率及能耗均要比在强酸、强碱条件下高,当pH为8.09时,经过6 h降解,氨氮的去除率达到100%,氨氮的降解速率为7 mg/(L.min),电流效率为45.23%,氨氮能耗为0.09kWh/g,COD的降解去除率达到50%,三氯甲烷产生的随着电解时间的增加而增加,电解6 h后三氯甲烷浓度从低于检测值升高至0.636 mg/L。     

三氯甲烷中有机磷农药混合标准样品的研制

确立了三氯甲烷中有机磷农药混合标准样品的制备、分析和定值方法,进行了标准样品的均匀性检验、稳定性监测及协作定值数据的不确定度评价。结果表明,三氯甲烷中有机磷农药混合标准样品的均匀性良好,至少在18个月的时间内稳定。     

顶空固相微萃取法测定饮用水中的氯仿

采用不同于传统涂层型纤维的体型活性碳纤维相微萃取测定饮用水中的氯仿,实验确定的萃取时间为６００ｓ,解吸时间为３ｍｉｎ,将萃取器针头完全插入气化室时的热解吸效果最佳,方法具有较好的重现性（４．１４％ＲＳＤ）,线性范围０－５０ｎｇ／ｍｌ,最低检测限为５ｎｇ／ｍｌ,用该方法和国家标准方法（ＧＢ５７５０－８５）对实际水样进行了分析比较,表明了顶空固相微萃取法检测结果与国标法相当,而灵敏度３．８倍于国标法,     

北京上甸子区域大气本底站甲基氯仿在线观测研究

利用GC-ECD在线观测系统,在北京上甸子区域大气本底站开展了甲基氯仿(CH3CCl3)2年在线观测,利用逐步逼近回归法进行本底值筛分,讨论了上甸子站CH3CCl3浓度水平及其变化趋势.该站2009年和2010年的年均大气CH3CCl3本底浓度(摩尔分数,下同)分别为(9.03±0.53)×10-12和(7.73±0.47)×10-12,本底数据出现频率为61.1%(2009年)和60.4%(2010年).上甸子站CH3CCl3浓度水平与北半球同纬度带本底站观测结果基本一致,低于文献报道的2001~2005年间我国华南区域和城市观测的结果.观测期间本底浓度呈下降趋势,下降率为1.39×10-12a-1.结合风向分析,该站CH3CCl3平均浓度最高的风向来自西南扇区,而平均浓度最低的风向来自东北扇区,不同风向的浓度差值分别为0.77×10-12(2009年)和0.52×10-12(2010年).2010年各风向CH3CCl3平均浓度比2009年降低1.03×10-12~1.68×10-12.     

毛细管气相色谱法测定环境空气中的氯仿

用活性炭采样管富集环境空气中的氯仿,以二硫化碳为解吸剂,经毛细管柱GC/ECD测定样品中的氯仿,以保留时间定性,峰高定量.     

电流密度对电化学氧化垃圾渗滤液效率影响

主要研究了不同电流密度对高氨氮垃圾渗滤液的电化学氧化效率,重点考察了电流密度(10、20、30、40 mA/cm)2对电解过程中的电解速率、电流效率、能耗以及三氯甲烷生成的影响。结果表明:在电流密度为30 mA/cm2时,电解6 h氨氮降解速率为7 mg/(L·min),COD降解速率为4.4 mg/(L·min),氨氮的氧化去除要先于COD的氧化去除;随着电流密度增加,电流效率逐渐增加,在电流密度为30 mA/cm2时达到45.23%,之后电流效率开始下降,电流密度为40 mA/cm2时电流效率为34%;能耗分析表明:随着电流密度增加,电解单位氨氮所需能耗先降低后升高,在电流密度为30 mA/cm2时达到最低0.09 kWh/g NH4+-N。在电流密度为40 mA/cm2时,电解6 h后三氯甲烷浓度从低于检测值升高至0.684 mg/L,产生速率为1.8μg/(L·min),三氯甲烷生成速率随着电流密度的增加而增加。     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Chloroform

This risk assessment on chloroform was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 23 studies for fish, 17 studies for invertebrates and 10 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a typical PNEC value of 72 µg/l. Due to limitations of the studies evaluated, a worst PNEC of 1 µg/l could also be used. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.2 µg chloroform per litre of water and a worst case PEC of 5 to 11.5 µg chloroform per litre of water. The calculated PEC/PNEC ratios give a safety margin of 6 to 360 between the predicted no effect concentration and the exposure concentrations. A worst case ratio, however, points to a potential risk for sensitive species. Refinement of the assessment is necessary by looking for more data. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

絮凝剂对饮用水消毒副产物与血清白蛋白作用的影响

通过体系紫外吸收和荧光强度的变化,研究了饮用水消毒副产物三溴甲烷(CHBr3)、三氯甲烷(CHCl3)与牛血清蛋白(BSA)之间的相互作用.结果表明,CHBr3和CHCl3均对BSA的内源荧光具有静态猝灭作用,其中CHBr3与BSA的结合强于CHCl3.Fe3+,Al3+和聚丙烯酰胺的加入也使BSA的荧光强度降低,与BSA的结合的强弱依次为:聚丙烯酰胺Fe3+Al3+.在二元体系的基础上,进一步研究了Fe3+,Al3+和聚丙烯酰胺对BSA-CHBr3(CHCl3)结合作用的影响.结果表明,Fe3+,Al3+和聚丙烯酰胺的存在使BSA-CHCl3、BSA-CHBr3的结合常数呈现降低的趋势,降低的趋势为Al3+聚丙烯酰胺Fe3+.