微污染水源水中消毒副产物前体物的去除

采用生物接触氧化法对北京某水库的微污染水源水中消毒副产物前体物的去除进行了研究。结果表明,水源水和生物接触氧化柱(简称生化柱)出水中的消毒副产物前体物氯化后形成的消毒副产物三卤甲烷(THMs)以CHCl3,CHCl2Br和CHBr2Cl为主,其中CHCl3含量最高,约占THMs的70％。水温对THMs前体物的去除有很大的影响,水温15．8℃时,生化柱对THMs前体物的去除率为65．2％;当水温由15．8℃降至12．8℃时,THMs前体物的去除率由65．2％降至18．8％。2002年11月至2003年1月间,生化柱UV254吸收值的平均去除率为11％。     

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。     

泰山顶臭氧及其前体物一氧化碳浓度变化规律

监测泰山顶O₃及其前体物CO的浓度,分析O₃和CO浓度的变化规律及其相关性.结果表明,泰山顶O₃小时平均浓度超过国家一级标准的频率为15.81%,CO小时平均浓度均达标;O₃浓度的日变化幅度较小,说明该地区受周围工业污染影响较小;O₃和CO浓度的日变化均呈一高一低的双峰型变化规律,二者具有很好的相关性,O₃浓度峰值一般滞后于CO,该区域O₃及其前体物CO浓度的变化主要受局地光化学过程控制;O₃浓度与CO浓度的日际变化的相关性也较好.     

Spatial and Seasonal Variations of Disinfection Byproducts (DBPs) in Drinking Water Distribution Systems of Istanbul City,Turkey

This study presents the seasonal and spatial variations of trihalomethanes (THMs) and haloacetic acids (HAAs) in 30 sampling points within three water distribution systems of Istanbul City, Turkey. The effects of surface water quality, seasonal variation, and species differences were examined. The occurrence of chlorinated THMs and HAAs levels was considerably lower in the system in which raw water is subjected to pre-ozonation versus pre-chlorination. Seasonal analysis of the data indicated that the median concentration of four THMs (THM₄) was higher than nine HAAs (HAA₉) concentrations in all three distribution systems sampling points. For all distribution systems monitored, the highest median THM₄ and HAA₉ concentrations were observed in the spring and summer season, while the lowest concentrations of these disinfection byproduct (DBP) compounds were obtained in the fall and winter period. Due to the higher level of bromide in supplying waters of these two systems, moderate levels of brominated DBP species have been observed in the Kagithane and Buyukcekmece distribution systems districts. In fact, Spearman partial correlations (Spearman rank correlation coefficients [rs]) tend to be higher among analogues in terms of number and types of substituent, especially TCAA with TCM (rs 0.91), and DBAA with DBCM (rs 0.90). In contrast, the hydraulic (residence time and flow rate) and chemical mechanisms (hydrolysis, volatilization, and adsorption) affect the fate and transport of DBPs in distribution systems. Seasonal and spatial variations of DBPs presented in this study have important implications on regulatory issues and from an epidemiological point of view.     

Dynamic risk assessment using failure assessment and Bayesian theory

To ensure the safety of a process system, engineers use different methods to identify the potential hazards that may cause severe consequences. One of the most popular methods used is quantitative risk assessment (QRA) which quantifies the risk associated with a particular process activity. One of QRA's major disadvantages is its inability to update risk during the life of a process. As the process operates, abnormal events will result in incidents and near misses. These events are often called accident precursors. A conventional QRA process is unable to use the accident precursor information to revise the risk profile. To overcome this, a methodology has been proposed based on the work of Meel and Seider (2006). Similar to Meel and Seider (2006) work, this methodology uses Bayesian theory to update the likelihood of the event occurrence and also failure probability of the safety system. In this paper the proposed methodology is outlined and its application is demonstrated using a simple case study. First, potential accident scenarios are identified and represented in terms of an event tree, next, using the event tree and available failure data end-state probabilities are estimated. Subsequently, using the available accident precursor data, safety system failure likelihood and event tree end-state probabilities are revised. The methodology has been simulated using deterministic (point value) as well as probabilistic approach. This Methodology is applied to a case study demonstrating a storage tank containing highly hazardous chemicals. The comparison between conventional QRA and the results from dynamic failure assessment approach shows the significant deviation in system failure frequency throughout the life time of the process unit.     

江苏省和邻区震群研究及其综合判定指标预报效能的评估

利用１９７０年以来江苏及邻区１０次震群资料，对其单项及综合指标作了计算和研究，根据《地震学分析预报方法程式指南》判断其前兆性。另外，对前兆震群与未来强震距离、间隔作了统计，并对其预报效能作了评估。     

二氧化氯预氧化对三氯乙醛前体物的去除与机制研究

以我国南方某水源水为研究对象,研究不同二氧化氯投加量下三氯乙醛(CH)前体物的去除情况,并对其去除机制进行分析.结果表明:当二氧化氯投加量为0.4 mg·L~(-1)时,CH生成势(CHFP)去除率最高,为14.3%,同时比CH生成势(SCHFP)亦有大幅削减,且二氧化氯预氧化对浊度和SUVA_(254)亦有较好的去除效果,但对COD_(Mn)去除效果不明显,DOC、UV_(254)则有小幅上升.二氧化氯去除CH前体物的机制是通过将含C=C双键和C=O双键的不饱和芳香性蛋白质类及微生物代谢产物类亲水性物质氧化降解或转化为其他非CH前体物的物质,从而使CH的生成量减少.     

大地介质极化率和二次场衰减特性时序观测与研究

大地介质极化率和二次场衰减特性时序观测是探索介质新的电性参数作为前兆观测项目的研究课题。经两年的观测研究发现,极化率存在年变化形态;主要研究的放电时段应放在１０～１００ｍｓ范围;在观测时段（１９９４ ０３～１９９５ １１）内台站３００ｋｍ范围发生的唯一一次大于５．０级的苍山５．２级地震（△３０４ｋｍ）前,极化率参数异常不明显,而极化率衰减度在该次地震前出现异常,衰减曲线极大值位移、曲线畸变、半衰时亦出现高值。对比地电阻率与极化率衰减度和半衰时的观测数据,在苍山５．２级地震前异常时间同步,呈低电阻率、高衰减度、高半衰时变化。研究结果表明应用介质新电性参数极化率作为前兆观测项目是可行的。     

数字化地震前兆台站的防雷措施

雷电灾害是气象自然灾害的一个组成部分.地震前兆台站的防雷问题是一个十分重要的问题,然而防雷技术目前在国际上尚未过关.随着数字化改造项目的实施,地震台站对防雷技术的要求越来越高.本文分析了雷电的形成、雷击的种类和雷电对数字化前兆地震台站的危害,介绍了几种针对数字化前兆台站的防雷措施,这些措施在实际的地震监测中取得了较好的效果,值得借鉴推广.     

成渝地区典型城市O3污染对人为源前体物排放敏感性模拟研究

以2019年3—4月臭氧（O₃）污染小高峰为例，应用空气质量模型CAMx-DDM法分析了成渝地区O₃浓度对人为源前体物排放敏感性，并用2020年"新冠"疫情防控及生产恢复导致的污染排放同比变化情景进行模拟验证.模拟结果表明成渝地区O₃对NO_x的敏感性为负、对VOCs的敏感性为正，其中，重庆市主城区、主城区以西地区、川南城市群和成都平原西部地区敏感性较高，与其自身污染排放源分布密集有关.以典型城市重庆市主城区为例，2019年3—4月O₃小时浓度对NO_x和VOCs的敏感性平均值分别为-19.14 μg·m^-3和7.25 μg·m^-3，两者表现出相反的日变化规律，且主要受到本地及周边区域的影响，模拟结果显示在所有区域VOCs排放均削减25%的情况下，3月和4月月均O₃日最大8 h浓度分别下降2.62 μg·m^-3和3.59 μg·m^-3.敏感性模拟得到2020年3月四川省和重庆市NO_x排放量同比下降8.00%和22.40%，VOCs同比下降1.00%和7.92%；4月NO_x排放量同比上升5.00%和9.50%，四川省VOCs同比持平，重庆市上升3.63%，与同期"新冠"疫情防控及生产恢复导致的实际排放情况非常一致.