石油烃污染地下水原位修复技术研究进展

概述了石油烃污染地下水原位修复技术的进展，包括原位化学氧化、原位电动修复、渗透反应格栅、冲洗、土壤气抽出、地下水曝气、生物修复，并对今后的研究发展趋势进行了展望。     

有机污染土壤原位化学氧化药剂投加方式的综述

原位化学氧化技术是修复有机污染土壤最经济有效的技术之一。药剂的投加与分散技术是原位化学氧化修复技术的核心。药剂投加与分散方式的选择与污染场地的土壤渗透性、特征水平、污染深度、氧化剂性质、修复费用等相关。阐述了直压式注射法、注射井法、土壤置换法和高压-旋喷注射法等药剂投加与分散技术的适用性、控制参数及优缺点等,引用工程实例对药剂投加与分散技术在原位化学氧化修复过程中的应用情况进行了论证。     

多环芳烃污染土壤的微生物修复技术

对生物修复技术中的微生物进行了分类，并阐述了微生物生物降解土壤中多环芳烃（PAHs）的基本原理。在此基础上，分析了国内外微生物生物修复技术的发展概况，采用图示法重点综述了原位处理技术和非原位处理技术的工艺流程，并列举了相应的工程应用实例。     

废旧聚酯织物原位反应增粘制备再生聚酯单丝研究

针对废旧聚酯织物杂质含量高、粘度波动大、再生产品附加值低的问题,采用原位反应增粘技术,通过“微醇解-自缩聚”工艺实现了废旧聚酯织物再生制备聚酯单丝。以聚酯泡泡料为原料,整个工艺过程包括熔融过滤、反应增粘、熔体输送和纺丝等工序,可实现再生聚酯单丝的连续化生产。研究对比了“微醇解-自缩聚”工艺过程各个阶段再生料的特性粘度和热性能,结果表明该工艺可提升泡泡料的特性粘度达到0.65 dL/g,热性能良好,满足纺丝要求,再生聚酯单丝可应用于生产聚酯拉链,产品性能满足标准QB/T 2173—2014要求。     

铁活化过硫酸盐修复石油烃污染土壤的研究进展

分析了Fe~0、Fe~(2+)和Fe~(3+)活化过硫酸盐氧化石油烃的机理,介绍了土壤中石油烃污染物降解的影响因素以及总结了铁活化过硫酸盐修复石油烃污染土壤技术的不足。指出应以铁活化过硫酸盐原位修复作为土壤中高浓度有机污染物的前处置方法,再结合微生物或植物修复等技术,以减少对土壤理化性质的影响;另外,检测仪器的发展有利于土壤修复技术的应用。     

1,2,4-三氯苯环境污染修复技术研究进展

综述了物理修复、化学修复、微生物修复及联合修复等几种主要的1,2,4-三氯苯(1,2,4-TCB)环境污染修复技术的研究进展。阐述了各种修复方法的反应原理、修复条件和效果,对比了各种修复方法的优缺点。提出今后的研究方向:解决物理吸附法修复1,2,4-TCB污染后的吸附剂的后续处理问题;优化化学降解1,2,4-TCB的工艺条件,避免二次污染,进行现场试验,实现工程应用;分离、培育1,2,4-TCB的优势降解菌种;深入研究联合修复技术的降解机理,实现1,2,4-TCB的高效、彻底降解。     

土壤氰化物污染生物修复技术研究进展

综述了植物修复、微生物修复和生物联合修复等土壤氰化物污染生物修复技术的降解机理、降解途径及降解影响因素的研究进展,探讨了氰化物生物修复技术的发展趋势和应用前景。指出基于提高修复时效和针对土壤复合污染类型的多技术融合研究、基于提高微生物耐受性和降解效率的菌株固定化及菌根真菌-植物联合技术研究以及基于工程化应用为导向的现场试验研究是未来研究的重点领域,为土壤氰化物污染的综合治理和修复提出了新思路。     

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。     

二氧化钛光催化降解甲醛反应动力学研究

以钛酸丁酯为前驱体，应用溶胶一凝胶法制备TiO2粉体和负载TiO2薄膜，考察了不同活化温度和活化时间对TiO2光催化降解甲醛性能的影响，并对TiO2薄膜光催化降解甲醛的反应动力学进行了研究。试验结果表明，在活化温度450℃、活化时间5h条件下，所得TiO2粉体及薄膜的光催化活性较好。不同初始浓度下甲醛光催化降解率与时间关系的动力学研究表明，一级反应动力学模型与试验数据拟合较好，方差R^2大于或等于0．99。     

化学还原法在Cr污染土壤修复中的应用

综述了Cr的地球化学特性和毒理学特性、化学还原反应机理和作用特点,分析了原位和异位化学还原法在Cr污染土壤修复中的应用,并对技术的工程实践提出建议.     

An evaluation of permeable reactive barrier projects in California

Permeable reactive barriers made of zero‐valent iron (ZVI PRBs) have become a prominent remediation technology in addressing groundwater contamination by chlorinated solvents. Many ZVI PRBs have been installed across the United States, some as research projects, some at the pilot scale, and many at full scale. As a passive and in situ remediation technology, ZVI PRBs have many attractive features and advantages over other approaches to groundwater remediation. Ten ZVI PRBs installed in California were evaluated for their performance. Of those ten, three are discussed in greater detail to illustrate the complexities that arise when quantifying the performance of ZVI PRBs, and to provide comment on the national debate concerning the downgradient effects of source‐zone removal or treatment on plumes of contaminated groundwater. © 2009 Wiley Periodicals, Inc.     

Sustainable Remediation Considerations for Treatment of 1,4‐Dioxane in Groundwater

1,4‐Dioxane remediation is challenging due to its physiochemical properties and low target treatment levels. As such, applications of traditional remediation technologies have proven ineffective. There are a number of promising remediation technologies that could potentially be scaled for successful application to groundwater restoration. Sustainable remediation is an important consideration in the evaluation of remediation technologies. It is critically important to consider sustainability when new technologies are being applied or new contaminants are being treated with traditional technologies. There are a number of social, economic, and environmental drivers that should be considered when implementing 1,4‐dioxane treatment technologies. This includes evaluating sustainability externalities by considering the cradle‐to‐grave impacts of the chemicals, energy, processes, transportation, and materials used in groundwater treatment. It is not possible to rate technologies as more or less sustainable because each application is context specific. However, by including sustainability thinking into technology evaluations and implementation plans, decisions makers can be more informed and the results of remediation are likely to be more effective and beneficial. There are a number sustainable remediation frameworks, guidance documents, footprint assessment tools, life cycle assessment tools, and best management practices that can be utilized for these purposes. This paper includes an overview describing the importance of sustainability in technology selection, identifies sustainability impacts related to technologies that can be used to treat 1,4‐dioxane, provides an approximating approach to assess sustainability impacts, and summarizes potential sustainability impacts related to promising treatment technologies. ©2016 Wiley Periodicals, Inc.     

Initial investigation on the use of waterjets to place amendments in the subsurface

Quasi‐passive in situ remediation technologies, such as the use of permeable reactive barriers to treat contaminated groundwater or applications of granular activated carbon to treat polychlorinated biphenyl (PCB)‐contaminated, near‐surface sediments, are proven or promising technologies that may be limited in application due to the traditional construction techniques normally used for placement in the environment. High‐pressure waterjets have traditionally been used to excavate material during mining operations or to cut rock or other durable material. Waterjets have the potential to place amendments in the subsurface at depths greater than those that can be obtained using traditional construction techniques. Likewise, waterjets may have less negative impact on near‐surface utilities and/or sensitive ecological systems. Laboratory experiments were performed to characterize the placement of two solid amendments in a simulated saturated aquifer. A second set of experiments was performed to characterize the effectiveness of waterjets for placing a third amendment in simulated intertidal sediments. The laboratory work focused on characterizing the nature of the waterjet penetration of the aquifer matrix and the saturated sediments, as well as the corresponding waterjet parameters of pressure, nozzle size, and injection time. The laboratory results suggest that field trials may be appropriate for future investigations. © 2005 Wiley Periodicals, Inc.     

Long-term Performance of a Permeable Reactive Barrier in Acid Sulphate Soil Terrain

Deep drainage technique utilised for flood mitigation in low-land coastal areas of Australia during the late 1960s has resulted in the generation of sulphuric acid in soil by the oxidation of pyritic materials. Further degradation of the subsurface environment with widespread contamination of the underlying soil and groundwater presents a major and challenging environmental issue in acid sulphate soil (ASS) terrains. Although several ASS remediation techniques recently implemented in the floodplain of Southeast Australia including operation of gates, tidal buffering and lime injections could significantly control the pyrite oxidation, they could not improve the long-term water quality. More recently, permeable reactive barriers (PRBs) filled with waste concrete aggregates have received considerable attention as an innovative, cost-effective technology for passive in situ clean up of groundwater contamination. However, long-term efficiency of these PRBs for treating acidic groundwater has not been established. This study analyses and evaluates the performance of a field PRB for treating the acidic water over 2.5 years. The pilot-scale alkaline PRB consisting of recycled concrete was installed in October 2006 at a farm of southeast New South Wales for treating ASS-impacted groundwater. Monitoring data of groundwater quality over a 30 month period were assessed to evaluate the long-term performance of the PRB. Higher pH value (~pH 7) of the groundwater immediately downstream of the PRB and higher rates of iron (Fe) and aluminium (Al) removal efficiency (>95%) over this study period indicates that recycled concrete could successfully treat acidic groundwater. However, the overall pH neutralising capacity of the materials within the barrier declined with time from an initial pH 10.2 to pH 7.3. The decline in the performance with time was possibly due to the armouring of the reactive material surface by the mineral precipitates in the form of iron and aluminium hydroxides and oxyhydroxides as indicated by geochemical modelling.     

Recent Developments in Cleanup Technologies

Although the reaction mechanics are somewhat mysterious, the use of iron for in situ groundwater treatment has recently gained considerable attention and respect in the remediation industry. The basic scientific principles of both applications of iron have been known for over a century; however, both were nearly unheard of as remediation technologies five years ago. Both technologies have a strong potential for widespread use. They are commercially available, have been proven in field studies, are less expensive than traditional pump and treat technologies, and, in many types of groundwater systems, may be able to meet difficult-to-achieve groundwater treatment standards. As these technologies continue to undergo development, there could be considerably more aggressive applications used to treat ground-water containing high concentrations of chlorinated organics and DNAPLs.     

Cost Evaluation for Selected Remediation Technologies

Relatively little data are available to document the historical cost for using common remediation technologies, and site managers often must rely on information from technology vendors and predictive models, which may not accurately reflect the experiences of previous technology users. To help address these concerns, the U.S. Environmental Protection Agency (EPA) conducted an evaluation of data on historical costs of common remediation technologies. Cost curves were developed for four technologies, showing the relationship between cost for remediation and quantity of material treated. Although costs are known to be highly site‐specific and affected by many factors, the curves are useful in illustrating the variability of historical costs and the economies of scale for treating relatively large quantities of material. © 2002 Wiley Periodicals, Inc.     

The use of zero‐valent iron injection to remediate groundwater: Results of a pilot test at the Marshall Space Flight Center

In situ treatability studies are being conducted to evaluate various in situ technologies to manage groundwater contamination at the NASA Marshall Space Flight Center in Huntsville, Alabama. The focus of these studies is to evaluate remediation options for contaminated (mostly aerobic) groundwater occurring within the basal portion of a clayey residuum called the rubble zone. The tension‐saturated media and unsaturated media lying above the rubble zone are also being treated where they make up a significant component of the contaminant mass. An in situ chemical reduction field pilot test was implemented (following bench‐scale tests) during July and August 2000. The test involved the injection of zero‐valent iron powder in slurry form, using the Ferox^SM process patented by ARS Technologies, Inc. The pilot test focused on trichloroethene (TCE)‐contaminated groundwater within the rubble zone. Maximum pre‐injection concentrations of about 72,800 micrograms per liter (μg/l) were observed and no secondary sources are believed to exist beneath the area. The potential presence of unexploded ordnance forced an implementation strategy where source area injections were completed, as feasible, followed by overlapping injections in a down gradient alignment to create a permeable reactive zone for groundwater migration. Eight post‐injection rounds of groundwater performance monitoring were completed. The results are encouraging, in terms of predicted responses and decreasing trends in contaminant levels. © 2003 Wiley Periodicals, Inc.