城市水污染物排放总量核定方法的研究

排污总量管理的首要任务是确定区域污染物排放总量。针对我国的水污染监测管理系统的现状,本文提出了一种“系统特征值核定排污总量方法”。该法以城市或城市某排污区的排污干管（或河道）输出的污染物总量实测值为基本依据,对各种排污总量的申报统计值进行正误的识别、校核与调整,汇总综合评价结果,核定排污总量及各个分量。该方法既使核定的排污总量增加科学性和准确性,又减少了核定的工作量;即使缺乏排污申报数据,也能迅速可靠地掌握城市的排污总量。该方法的有效性已在济南市应用中得到证实     

电极材料对脉冲等离子体降解有机废气的影响分析

用脉冲等离子体降解有机废气,对甲苯、二甲苯的降解率达73％～91％,对二氯甲烷的降解率达82％。在实验中发现电极材料的不同会影响分解效果,其中钨电极的降解率最高。本文运用等离子体化学中放电气体电子碰撞电离和化学自由基产生的机理以及阴极电子学中带电粒子轰击电极表面激发二次电子发射的理论,通过比较不同金属电极的二次电子发射系数δ,研究电极材料对脉冲等离子体降解有机废气影响的机理,发现主要是由于不同电极材料δ值的差异引起降解率的差异,电极稳定性对降解率和电极寿命也有重要影响。在实验的三种电极材料中钨的δ值最大,其最大二次电子发射系数δ_m为1.4,铜其次为1.29,不锈钢最小约为1.24,这成为导致三者降解率差异的主要原因。     

道路全封闭声屏障的实践

简要介绍了在城市汽车道路桥上安装的一定长度的全封闭声屏障 ,简要分析了全封闭声屏障特有的隔声效果 ,介绍了全封闭声屏障的结构型式及实施过程中主要的技术问题     

高炉原料矿槽槽上除尘方式综述

槽上卸料车及矿槽口尘源点具有移动性特征,有效的矿槽槽口密闭以及可靠的随卸料车移动的风管连接装置,是保证除尘良好效果的要点.常用的除尘方法各有其特点和适用条件,应根据作业方式及矿槽结构状况有针对性的采用.     

德国节能减排多措并举

德国针对能源匮乏的现状,把节约能源作为政府能源开发利用的一贯政策来推动。文章介绍了德国政府在重视节能技术研发、节能服务体系建设、能源统计、建筑节能、可再生能源开发和综合利用以及加强宣传教育、增强节约意识等方面所做的有益探索实践和取得的经验。对我国开展节能减排工作有较好借鉴意义。     

上海外环线道路声屏障的施工及降噪效果

上海外环线交通噪声污染十分突出,通过安装大型声屏障取得了较满意的效果。本文介绍了外环线两段道路声屏障的施工安装以及实测降噪效果,可供类似工程参考。     

介质阻挡放电等离子体技术处理难降解有机废水的研究进展

综述了介质阻挡放电(DBD)等离子体技术处理难降解有机废水的国内外研究现状以及最新研究成果.概括出DBD等离子体处理难降解有机废水的影响因素和一般性结论;从微观和宏观两个方面总结和分析了DBD等离子体处理难降解有机废水的作用机理;探讨了DBD等离子体技术处理难降解有机废水的技术瓶颈以及发展方向.     

Integration of traditional and innovative characterization techniques for flux-based assessment of Dense Non-aqueous Phase Liquid (DNAPL) sites

Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( 10 kg), which is also reflected in small source mass discharge ( 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of  6 g/day at a plume control plane  175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult. Our analysis, based on a synthesis of the archived data and new data, suggests that source treatment is unwarranted, and that containment of the large TCE plume ( 1.2 km long,  0.3 km wide; 17 m deep;  2000–2500 kg TCE mass) or institutional controls, along with a long-term flux monitoring program, might be necessary. The flux-based site management approach outlined in this paper provides a novel way of looking beyond the complexities of groundwater contamination in heterogeneous domains, to make intelligent and informed site decisions based on strategic measurement of the appropriate metrics.     

Effects of initial iron corrosion rate on long-term performance of iron permeable reactive barriers: Column experiments and numerical simulation

Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO₃ were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from evolution of geochemical conditions should be considered in the design of iron PRBs.     

乌江干流中上游水电梯级开发水温累积效应

以乌江流域洪家渡库尾至乌江渡坝下的水电工程干扰典型段为研究区域,利用建坝前后的水温实测资料,采用建坝前天然水温和建坝后下泄水温比较法,对乌江干流梯级水库水温时空分布特征进行分析。研究结果表明：对天然水温改变最大的电站为洪家渡和乌江渡,前者是受水库水温结构自身影响,后者是梯级联合运行的结果;梯级联合运行使库区水温分层有所减弱,随着时间的推移或上游梯级电站的建成,电站下泄水温年变化过程趋于均化,与天然水温的延迟也越加明显;不同的水库水温结构对水温累积效应的影响也各不相同,稳定分层型水库对水温累积具有正效应,混合型水库具有负效应,过渡型水库处于两者之间,体现了梯级电站的水温累积影响,为研究减缓下泄低温水的对策措施提供依据和参考。