Phenanthrene sorption/desorption sequences provide new insight to explain high sorption coefficients in field studies

The sorption coefficients obtained in field investigation vary greatly from laboratory sorption experiments. The possible reasons were discussed in literature. Observing the commonly reported desorption hysteresis, this study proposed that the unclear sorption history of the field study could also result in the diverse sorption coefficients. This study conducted a comparative study regarding phenanthrene sorption/desorption behavior in low-concentration multi-time sorption process and the commonly applied high-concentration one-time sorption process. The sorption coefficients determined during the desorption process were much higher than those at sorption process. Thus, the prediction of sorption coefficient should be related with sorption history. Desorption hysteresis was increased with increased equilibration time and decreased solid-phase concentration. In addition, although the apparent contact time between sorbate and sorbent was shorter for low-concentration multi-time sorption, the desorption hysteresis was much stronger, which consequently result in higher sorption coefficients in comparison to high-concentration one-time sorption. Pore swelling or diffusion-controlled sorption kinetics could not explain this phenomenon. This study calls for research attention on sorption history, especially for field investigations.     

Delineating landfill leachate discharge to an arsenic contaminated waterway

Discharge of contaminated ground water may serve as a primary and on-going source of contamination to surface water. A field investigation was conducted at a Superfund site in Massachusetts, USA to define the locus of contaminant flux and support source identification for arsenic contamination in a pond abutting a closed landfill. Subsurface hydrology and ground-water chemistry were evaluated in the aquifer between the landfill and the pond during the period 2005-2009 employing a network of wells to delineate the spatial and temporal variability in subsurface conditions. These observations were compared with concurrent measures of ground-water seepage and surface water chemistry within a shallow cove that had a historical visual record of hydrous ferric oxide precipitation along with elevated arsenic concentrations in shallow sediments. Barium, presumably derived from materials disposed in the landfill, served as an indicator of leachate-impacted ground water discharging into the cove. Evaluation of the spatial distributions of seepage flux and the concentrations of barium, calcium, and ammonium-nitrogen indicated that the identified plume primarily discharged into the central portion of the cove. Comparison of the spatial distribution of chemical signatures at depth within the water column demonstrated that direct discharge of leachate-impacted ground water was the source of highest arsenic concentrations observed within the cove. These observations demonstrate that restoration of the impacted surface water body will necessitate control of leachate-impacted ground water that continues to discharge into the cove.     

工业废水锑排放标准限值的制订

分析了国内外锑标准的研究现状,总结了工业废水锑排放标准的制订原则,并以太湖流域某湖泊水体为例,介绍了工业废水锑排放标准限值的制订流程。通过建立环境容量模型,计算区域水体允许纳污量,推算出在上游来水为极端最枯流量、枯水年平均流量、平水年平均流量情形下,研究区域内相关企业允许排放到水体中的锑质量浓度分别为19.10μg/L、28.47μg/L、48.92μg/L。考虑最不利情形,兼顾锑污染处理的技术经济可行性,建议直排点源及印染废水集中式污水处理厂的出水锑质量浓度标准限值为20μg/L。     

排污许可制度实施情况监督评估体系研究

排污许可制度实施监督管理在排污许可制度设计中具有重要地位,而我国排污许可制度的监督管理体系尚未建立.在对排污许可及相关制度实施情况监督评估现状分析基础上,提出我国排污许可制度实施评估体系的总体思路、总体框架,并就排污许可制度实施监督评估内容进行设计,以期为我国排污许可制度实施提供借鉴.     

Colombia's discharge fee program: Incentives for polluters or regulators?

Colombia's discharge fee system for water effluents is often held up as a model of a well-functioning, economic incentive pollution control program in a developing country. Yet few objective evaluations of the program have appeared. Based on a variety of primary and secondary data, this paper finds that in its first 5 years, the program was beset by a number of serious problems including limited implementation in many regions, widespread noncompliance by municipal sewerage authorities, and a confused relationship between discharge fees and emissions standards. Nevertheless, in some watersheds, pollution loads dropped significantly after the program was introduced. While proponents claim the incentives that discharge fees created for polluters to cut emissions in a cost-effective manner were responsible, this paper argues that the incentives they created for regulatory authorities to improve permitting, monitoring, and enforcement were at least as important.     

城市污水全量循环方法学研究

城市的快速发展对水资源、水环境的压力不断增大,城市生活污水排放量逐年增长。为节约水资源,改善水环境,将城市污水深度处理后回用于工业、市政等方面,设置不同情景对城市污水全量循环方法学开展研究,以实现城市污水不外排。     

沈阳城市污水排放系统现状与分析

主要介绍了沈阳市排水系统的概况及水质状况，并对削减城市污水排放的方式进行了分析。     

浅谈静电及其防护

静电危害的严重性和防范的必要性，日益受到人们的注意和重视。本文从静电的产生，静电危害、静电防护等几方面探讨有关静电和静电防护、检测的一些问题。     

佛山市汾江河流域水污染物排放标准研究

随着汾江河综合整治的深入,现有排放标准已无法满足汾江河流域水体治理要求,迫切需要收紧汾江河流域排放标准。本论文简单介绍了汾江河流域基本情况,确定了标准制定原则及技术路线,分析了汾江河水环境和工业污染源现状,从而确定流域重点污染源和特征污染物。通过建立水流-水质模拟系统,计算汾江河主要污染因子水环境容量,并进行标准实施后的效益分析。     

环境管理的经济手段分析

环境管理中占主导地位的是直接管制手段，直接管制手段就是政府行政管理机构以指令控制的方式向污染排放者下达法令或提出具体的标准。直接管制在环境管理中取得了很好的成绩。但在环境和经济的协调效率上还不够灵活有效，显示出相当的局限性。阐述了排污收费,使用费，产品费,排污权交易、环境税收等常用的经济手段，并进行了比较分析。