丛枝菌根真菌-植物修复矿区重金属污染土壤的研究进展

阐述了丛枝菌根真菌(AMF)-植物对重金属污染土壤的修复机制,重点介绍了AMF-植物联合技术在金属矿区、煤矿区重金属污染土壤修复中的应用,并对今后该技术的发展和应用前景进行了展望。指出:加大AMF-植物联合修复技术的研究和实践,将会带来更好的经济效益和环境效益。     

化学淋洗—H2O2-O3-UV复合催化氧化技术修复硝基甲苯一氯、二氯代物污染土壤工程实例

针对某退役化工企业地块的关注污染物硝基甲苯一氯、二氯代物的历史形成、污染状况和土质特点,在小试技术验证的基础上,采用化学淋洗—H₂O₂-O₃-UV复合催化氧化技术进行受污染土壤异位修复的工程实践。结果表明,该技术能较好地适用于关注污染物的土壤修复工程,修复后指标明显优于目标值,且造价和运行费用较低,具有显著的社会效益、经济效益和环境效益,有一定的推广价值。     

The horizontal reactive media treatment well (HRX Well®) for passive in situ remediation: Design,implementation, and sustainability considerations

A new in situ remediation concept termed a Horizontal Reactive Media Treatment Well (HRX Well^®) is presented that utilizes a horizontal well filled with reactive media to passively treat contaminated groundwater in situ. The approach involves the use of a large‐diameter directionally drilled horizontal well filled with solid reactive media installed parallel to the direction of groundwater flow. The engineered contrast in hydraulic conductivity between the high in‐well reactive media and the ambient aquifer hydraulic conductivity results in the passive capture, treatment, and discharge back to the aquifer of proportionally large volumes of groundwater. Capture and treatment widths of up to tens of feet can be achieved for many aquifer settings, and reductions in downgradient concentrations and contaminant mass flux are nearly immediate. Many different types of solid‐phase reactive treatment media are already available (zero valent iron, granular activated carbon, biodegradable particulate organic matter, slow‐release oxidants, ion exchange resins, zeolite, apatite, etc.). Therefore, this concept could be used to address a wide range of contaminants. Laboratory and pilot‐scale test results and numerical flow and transport model simulations are presented that validate the concept. The HRX Well can access contaminants not accessible by conventional vertical drilling and requires no aboveground treatment or footprint and requires limited ongoing maintenance. A focused feasibility evaluation and alternatives analysis highlights the potential cost and sustainability advantages of the HRX Well compared to groundwater extraction and treatment systems or funnel and gate permeable reactive barrier technologies for long‐term plume treatment. This paper also presents considerations for design and implementation for a planned upcoming field installation.     

两种电动修复的对比性研究

在自主研发的电动力学装置中,分别采用脉冲电源和直流电源两种供电方式对相同污染浓度的镉污染土壤进行修复,对比分析脉冲电动修复和恒直流电动修复的修复效果和能耗。实验结果表明:与恒直流电动修复相比,在相同的修复时间内,脉冲电动修复处理之后的土壤中镉的去除率提高29.6%~31.0%;在达到相同修复效果(即脉冲电动修复处理和恒直流电动修复处理过程中阴极电导率均为1285μs/cm时),脉冲电动修复的能耗可节省60.8%。     

污染场地修复中二次污染防治措施探讨

土壤污染问题日益凸显,污染土壤修复成为环境保护工作的重点。本文从大气、水、噪声、固体废物及土壤环境等五个方面,对污染土壤修复过程中可能产生的二次污染进行分析,并对二次污染防治措施进行了探讨,以期为之后的污染土地修复工程中二次污染防治工作提供参考。     

多环芳烃污染土壤化学氧化修复技术应用研究

本文在分析了PAHs法污染土壤修复常用技术基础上,以化学氧化修复技术为例,结合案例,探讨了该技术在多环芳烃污染土壤修复中的应用,对打赢蓝天碧水净土保卫战具有积极的现实意义。     

国内土壤环境污染现状与防治措施

土壤是农业生产的物质基础,其环境污染影响着农产品质量、人体健康与国民经济发展。本文根据实际土壤环境污染情况调查结果,主要阐述了国内土壤环境污染现状,介绍了当前可应用的土壤污染修复技术,并针对污染现状提出了几点防治措施。     

Model-based evaluation of controlled-release systems in the remediation of dissolved plumes in groundwater

Controlled-release, semi-passive reactive barrier systems have been recently developed as a long-term treatment option for controlling the spread of contaminant plumes in groundwater. This paper describes a new computer code, and applies it to study coupled processes of solute release, reaction, and mass transport in an in situ remediation scheme using the controlled release of potassium permanganate. Confidence with the modeling approach was developed by model verifications and simulating results of a pilot-scale test-cell experiment. Sensitivity analyses indicated the possibilities of treatment inefficiencies due to inability of transverse dispersion to mix the permanganate (MnO(4)(-)) within the zone of reaction, fluctuations in source strength due to variations in flow velocity, and the small length of treatment zone due to strong soil utilization of MnO(4)(-). Although problems associated with the fluctuating source strength and strong soil utilization can be addressed by optimizing the release rate, the inefficiency of transverse dispersion to create mixing could pose a serious limitation. Through a series of model simulations, a system of injection/withdrawal wells in a doublet arrangement was developed to facilitate lateral spreading and mixing of MnO(4)(-). A well-mixed, stable MnO(4)(-) zone with predetermined size (DxL=8m x 2m) and concentration ranges (1.5-20 mg l(-1)) was created by four 1-day injection/withdrawal pumping periods over 24 d. This type of mixing zone may persist for many years with periodic well mixing and replacements of exhausted controlled-release forms. Coupled use of the generalized code with field hydrologic data will help to optimize the design and operation of controlled-release systems in practice.     

Transport of cadmium and assessment of phytotoxicity after electrokinetic remediation

The use of ethylene diamine tetraacetic acid (EDTA) on the electrokinetic removal of cadmium-contaminated soil was evaluated. A total of four different tests were conducted using EDTA as a washing solution as well as a purging solution at the electrode compartments. The efficiency of electrokinetic extraction was significantly influenced by the pH of the soil medium. The results show that EDTA was effective in desorbing cadmium at a high pH, with Cd-EDTA(-) anion complexes migrating toward the anode. At low pH values near the anode area, cadmium existed as Cd(2+), migrating toward the cathode. Such contradicting directions of cadmium have resulted in its detrimental removal from the soil cell. However, accumulation of cadmium near the cathode was observed at the end of the tests due to the dominating low pH in the soil cell. The phytotoxicity after the electrokinetic process was investigated using Sorghum saccharatum, Lepidium sativum and Sinapis alba plants. The germination index was a major endpoint estimated by measuring seed germination and shoot elongation. The results obtained show that the phytotoxicity was increased after electrokinetic extraction. Despite, the extensive cadmium removal from two-thirds of the cell, the low pH of the soil was the principal parameter exhibiting the phytotoxicity.     

Urban property values and contaminated sites: A hedonic analysis of Sydney, Nova Scotia

This study examines the impact of contaminated sites on urban property values in Sydney, Nova Scotia, Canada. The property value effects are examined using an inverse distance specification from the property to the site. A hedonic method employing ordinary least-square technique was used for model estimation. The results show that the presence of contaminated sites has had significant negative effect on the value of residential property. This negative effect, however, is largely localized to within few hundred metres of the sites. The total property value loss in urban Sydney from the contaminated sites is estimated to be $CDN 36 million.