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。     

Pneumatic fracturing to remove VOCS

A new process for enhancing in-situ remediation of low-permeability soil and rock formations is presently under development at the Hazardous Substance Management Research Center (HSMRC). The patented process, known as ?pneumatic fracturing,”? consists of injecting high-pressure air or other gas into contaminated geologic formations at controlled flow rates and pressures. In fine-grained soils such as clay, pneumatic fracturing creates conductive channels in the formation, thereby increasing the permeability and exposed surface area of the contaminated soil. The potential benefits of pneumatic fracturing are significant, since in-situ remedial technologies are essentially limited by the pore gas exchange rate of the soil being treated. This article describes the results of a recent demonstration of pneumatic fracturing at an industrial site to enhance a volatile organic compound (VOC) extraction system. After establishing the baseline removal rate of soil gas effluent from the clay, soil surrounding the extraction system was fractured to enhance VOC with drawal. A substantial improvement in the VOC removal rate was observed, including: (1) flush effluent concentrations that increased up to 200 times; and (2) air flows in the formation that increased up to 1,000 times.     

Effective low-temperature thermal aeration of soils

Low-temperature thermal aeration (LTTA) is a remedial technology developed by Canonie Environmental Services Corp. (Canonie) for use on soils containing nonchlorinated hydrocarbons, chlorinated solvents, volatile organic compounds (VOCs), chlorinated pesticides, and low levels of polynuclear aromatic hydrocarbons (PAHs). The LTTA system separates these hazardous constituents from excavated soils and allows the treated soils to be redeposited on-site without restriction. This article describes the various components and operation of LTTA systems for the remediation of soils contaminated with chlorinated and nonchlorinated constituents. The article also details the results of projects completed to date, principally for soil impacted with chlorinated hydrocarbons, and discusses the general characteristics and results of systems used for soils contaminated with nonchlorinated hydrocarbons (gasoline, etc.).     

Triad case study: Former small arms training range

The U.S. Army Corps of Engineers (US ACE) used the Triad approach to expedite site characterization of contaminated soil at the Former Small Arms Evergreen Infiltration Training Range in Fort Lewis, Washington. The characterization was designed to determine if surface soils contain significant concentrations of metals, with the focus on collecting sufficient data for determining appropriate future actions (i.e., risk analysis or soil remediation). A dynamic sampling and analytical strategy based on rapid field‐based analytical methods was created in order to streamline site activities and save resources while increasing confidence in remediation decisions. Concurrent analysis of soil samples during the demonstration of method applicability (DMA) used both field portable X‐ray fluorescence (FPXRF) and laboratory methodologies to establish a correlation between FPXRF and laboratory data. Immediately following the DMA, contaminated soil from the impact berm was delineated by collecting both FPXRF data and fixed laboratory confirmation samples. The combined data set provided analytical results that allowed for revisions to the conceptual site model for the range and directed additional sample collection activities to more clearly determine the extent and distribution of soil contamination. © 2004 Wiley Periodicals, Inc.     

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。     

重金属污染土壤生物毒性的发光菌法测定及评价

向土壤中人为投加重金属污染物,制备了重金属含量不同的一系列污染土壤,对土壤重金属浸提条件进行了探究,并应用明亮发光杆菌T3（Photobacterium phosphoreum T3）对单一Cu、Cd和Pb污染及Cu-Cd和Cu-Pb复合重金属污染土壤的生物毒性进行了测定。实验结果表明,土壤重金属的最佳浸提剂为0.1 mol/L HCl溶液,最佳浸提时间为2.0 h。在单一重金属污染条件下：Cu表现出低浓度促进生长、高浓度抑制生长的双重生物效应,而Cd和Pb则表现出浓度与生物毒性的正相关性;3种重金属污染土壤的毒性强弱顺序为Cd>Pb>Cu。在复合重金属污染条件下,由于重金属之间的相互作用,污染土壤的生物毒性增强。     

Electrochemical remediation of heavy metal contaminated soils

Over the years, many soils have been contaminated with toxic heavy metals as a result of a variety of industrial and military activities. Electrokinetic soil treatment is an emerging technology that could prove to be very effective in the remediation of these sites. “Real-world” heavy metal contaminated (Pb(II), Cd(II), and Cr(III)) soils from three military sites with varying soil properties were subjected to electrokinetic treatment in the laboratory. Metal extractants (chelating agents and acids) were studied and found to be effective in enhancing the electrokinetic process. Results indicated that heavy metal removal efficiencies varied in the three soils tested. In one case, removal efficiencies of 90 percent and 60 percent were obtained for Cd and Cr, respectively, for the nitric acid amended experiments. For another case, over 60 percent of the total Pb in the system was deposited near the cathode for the non-amended and the citric-acid amended tests. Conversely, in the third case, the electrokinetic soil-washing treatment process failed to produce significant removal of any metal contaminant. The discrepancies that exist between the metal removal results of the three soils were attributed to the different physiochemical characteristics of each soil.     

火炸药生产废水污染土壤修复的研究进展

总结了国内外化学修复法和生物修复法修复火炸药生产废水污染土壤的研究进展。比较了各种方法的优缺点,提出了未来火炸药生产废水污染土壤修复技术的研究方向。指出:应将物理修复法、化学修复法及生物修复法相结合,将修复定位于综合化、彻底化及可利用化,以期达到火炸药生产废水污染土壤的无害化治理。     

模拟酸雨对土壤修复中重金属淋溶特征及土壤持水能力的影响

以磷酸二氢钾（PDP）钝化后的重金属污染土壤为研究对象,通过室内土柱淋溶和土壤吸水实验,考察pH为3.1、4.6和5.1的模拟酸雨对污染土壤修复过程中重金属淋溶特征及土壤持水能力的影响。实验结果表明：PDP处理显著增加了淋出液的pH、电导率、TOC和正磷酸盐态磷（ZP）含量,在淋溶初期显著降低了淋出液的Cu、Cd和Pb含量,但在淋溶后期增大了Pb含量;土壤持水量与电导率、pH、TOC和ZP含量呈现极显著负相关性;土壤修复过程中,有机质的淋失、盐分含量及pH的增大可引起土壤持水能力的减弱。     

Low intervention soil remediation approaches

Traditional bioremediation approaches have been used to treat petroleum source contamination in readily accessible soils and sludges. Contamination under existing structures is a greater challenge. Options to deal with this problem have usually been in the extreme (i.e., to dismantle the facility and excavate to an acceptable regulated residual, or to pump and treat for an inordinately long period of time). The excavated material must be further remediated and cleanfill must be added to close the excavation. If site assessments were too conservative or incomplete, new contamination adulterating fill soils may result in additional excavation at some later date. Innovative, cost-efficient technologies must be developed to remove preexisting wastes under structures and to reduce future remediation episodes. An innovative soil bioremediation treatment method was developed and evaluated in petroleum hydrocarbon contaminated (PHC) soils at compressor stations of a natural gas pipeline running through Louisiana. The in-situ protocol was developed for remediating significant acreage subjected to contamination by petroleum-based lubricants and other PHC products resulting from a chronic leakage of lubricating oil used to maintain the pipeline itself. Initial total petroleum hydrocarbon (TPH) measurements revealed values of up to 12,000 mg/kg soil dry weight. The aim of the remediation project was to reduce TPH concentration in the contaminated soils to a level of <200 mg/kg soil dry weight, a level negotiated to be acceptable to state and federal regulators. After monitoring the system for 122 days, all sites showed greater than 99-percent reduction in TPH concentration.     

Use of Large‐Scale Electrokinetic and ZVI Treatment for Chlorinated Solvent Remediation at an Active Industrial Facility

The combination of electrokinetic and zero‐valent iron (ZVI) treatments were used to treat soils contaminated with chlorinated solvents, including dense nonaqueous phase liquid (DNAPL), at an active industrial site in Ohio. The remediation systems were installed in tight clay soils under truck lots and entrances to loading docks without interruption to facility production. The electrokinetic system, called Lasagna^TM, uses a direct current electrical field to mobilize contaminant via electroosmosis and soil heating. The contaminants are intercepted and reduced in situ using treatment zones containing ZVI. In moderately contaminated soils around the Lasagna^TM‐treated source areas, a grid of ZVI filled boreholes were emplaced to passively treat residual contamination in decades instead of centuries. The remediation systems were installed below grade and did not interfere with truck traffic during the installation and three years of operation. The Lasagna^TM systems removed 80 percent of the trichloroethylene (TCE) mass while the passive ZVI borings system has reduced the TCE by 40 percent. The remediation goals have been met and the site is now in monitoring‐only mode as natural attenuation takes over. © 2014 Wiley Periodicals, Inc.     

A study of treatment options to remediate explosives and perchlorate in soils and groundwater at Camp Edwards,Massachusetts

The Army National Guard initiated an Innovative Technology Evaluation (ITE) Program in March 2000 to study potential remedial technologies for the cleanup of explosives‐contaminated soil and groundwater at the Camp Edwards site on the Massachusetts Military Reservation. The soil technologies chosen for the ITE program were: soil washing, chemical oxidation, chemical reduction, thermal desorption/destruction (LTTD), bioslurry, composting, and solid phase bioremediation. The technologies were evaluated based on their ability to treat both washed and untreated soil. A major factor considered was the ability to degrade explosives, such as RDX, found in particulate form in the soils. The heterogeneous nature of explosives in soils dictates that the preferred technology must be able to treat explosives in all forms, including the particulate form. Groundwater remediation technologies considered include: in situ cometabolic reduction, two forms of in situ chemical oxidation, Fenton‐like oxidation and potassium permanganate. This article presents the results of each of the remedial technologies evaluated and discusses which technologies met the established ITE performance goals. © 2003 Wiley Periodicals, Inc.     

土壤残留塑料的热降解脱附研究

针对土壤的塑料污染问题,提出一种采用热脱附降解技术修复污染土壤的方法.选取4种土壤中常见的残留塑料(聚乙烯(PE)、聚氯乙烯(PVC)、聚对苯二甲酸乙二酯(PET)、聚丙烯(PP))为研究对象,通过控制热解温度和土壤含水率对各污染土壤的修复效果进行探究.实验结果表明:在500℃的最佳热解温度下处理60 min,PE、P...     

生物炭修复Cd,Pb污染土壤的研究进展

随着矿产开采、冶炼等工业活动以及污水灌溉、施用污泥和劣质化肥等农业活动的进行,Cd,Pb等有害重金属不断进入农业环境中,对农田、菜地等造成污染。生物炭作为重要的土壤改良剂,在对Cd,Pb污染土壤的修复中表现出巨大的潜力。从生物炭的特性及制备、修复效果及其影响因素、修复机理等方面,对近年来国内外有关生物炭修复Cd,Pb污染土壤的研究成果和现状进行了总结,并对生物炭修复Cd,Pb污染土壤的发展前景和未来研究方向进行了展望。     

石油污染土壤的微生物修复技术

介绍了石油污染土壤微生物修复技术的影响因素;概述了生物刺激、生物强化、固定化微生物、植物-微生物联合修复以及电动-微生物联合修复石油污染土壤的技术原理,分析了现阶段土壤修复过程中面临的难题,预测了微生物修复技术的研究方向。指出优化微生物的环境条件、培育新型高效的基因工程菌和开发经济高效的新型修复技术等将是未来微生物修复技术的发展趋势。     

Treatment technology for remediation of wood preserving sites: Overview

This is the first in a series of five articles describing the applicability, performance, and cost of technologies for the remediation of contaminated soil and water at wood preserving sites. Site‐specific treatability studies conducted under the supervision of the United States Environmental Protection Agency (US EPA), National Risk Management Research Laboratory (NRMRL), from 1995 through 1997 constitute much of the basis for the evaluations presented, although data from other treatability studies, literature sources, and actual site remediations have also been included to provide a more comprehensive evaluation of remediation technologies. This article provides an overview of the wood preserving sites studied, including contaminant levels, and a summary of the performance of the technologies evaluated. The subsequent articles discuss the performance of each technology in more detail. Three articles discuss technologies for the treatment of soils, including solidification/stabilization, biological treatment, solvent extraction and soil washing. One article discusses technologies for the treatment of liquids, water and nonaqueous phase liquids (NAPLS), including biological treatment, carbon adsorption, photolytic oxidation, and hydraulic containment. The reader should be aware that other technologies including, but not limited to, incineration, thermal desorption, and base catalyzed dehalogenation, also have application for treating contaminants on wood preserving sites. They are not discussed in these five articles since the focus was to evaluate lesser known and hopefully lower cost approaches. However, the reader should include consideration of these other technologies as part of any evaluation or screening of technologies applicable to remediation of wood preserving sites.     

Characterizing soils contaminated with heavy metals: A uranium contamination case study

To stem rising remediation costs for soils contaminated with hazardous metals, increased emphasis is being placed on the development of in-situ and ex-situ treatment technologies. Often, a lack of basic information on the chemical and physical characteristics of the soil and contaminants hampers treatability studies used to design these technologies. This article proposes and demonstrates a characterization program to meet these information needs, employing standard analytical techniques coupled with advanced spectroscopy and microscopy techniques. To support treatments involving physical separation strategies, the program uses standard analytical techniques to characterize the soil and the association of contaminants with different soil fractions (e.g., size and density fractions). Where chemical treatments are required, spectroscopy and microscopy methods are employed to yield quantitative information on the oxidation state and speciation of the contaminant. Examples demonstrate the use of measured soil and contaminant characteristics in the screening of alternative treatment technologies and in the selection of soils for use in treatability studies. Also demonstrated is the use of these characterization tools in the design and optimization of treatment strategies and in support of risk assessment determinations.     

Rotary drum soil blending for source zone remediation: Various application scenarios

Mechanical blending of contaminated soil with amendments has recently reemerged as an important treatment technology. From its original application using large‐diameter augers in the early 1990s to the current use of rotary drum blenders, soil blending is being used as an alternative to other remediation technologies like amendment injection and soil vapor and groundwater extraction. Shallow (approximately 10 m below ground surface [bgs] or less) soil blending also offers an alternative to excavation and disposal. Soil blending has been used to remediate a site with various contaminants including, but not limited to, chlorinated solvents, petroleum, and metals. The types of soils susceptible to soil blending vary from sands and gravels to silts and clays to fractured rock and combinations of all of these. The types of amendments blended include oxidants, reducing agents, biological enhancements, and stabilizing amendments. Soil blending systems deliver the power to the mixing head to adequately mix the soil and amendment to enhance remediation effectiveness. Since long‐term contamination is often a result of heterogeneously distributed residual contaminant in localized source zones that are difficult to access, the typical aim of soil blending is to homogenize the soil while effectively distributing amendment to these zones made accessible by blending. By effectively homogenizing the soil, however, soil blending will increase the void ratio and disrupt the shear strength and bearing capacity of the soil so an important component of a soil blending technology is proper recovery of these geotechnical parameters. This can be achieved by using well‐known soil improvement techniques such as amending all or a portion of the blended area with Portland cement or lime. Several case studies of soil blending treatments of different contaminants and amendments in various soil types are provided.     

Sustainable soil remediation by refrigerated condensation at sites with “high‐concentration” recalcitrant compounds and NAPL: Two case studies

Remediation of recalcitrant compounds at sites with high concentrations of volatile organic compounds (VOCs) or nonaqueous‐phase liquids (NAPLs) can present significant technical and financial (long‐term) risk for stakeholders. Until recently, however, sustainability has not been included as a significant factor to be considered in the feasibility and risk evaluation for remediation technologies. The authors present a framework for which sustainability can be incorporated into the remediation selection criteria focusing specifically on off‐gas treatment selection for soil vapor extraction (SVE) remediation technology. SVE is generally considered an old and standard approach to in situ remediation of soils at a contaminated site. The focus on off‐gas treatment technology selection in this article allows for more in‐depth analysis of the feasibility evaluation process and how sustainable practices might influence the process. SVE is more commonly employed for recovery of VOCs from soils than other technologies and generally employs granular activated carbon (GAC), catalytic, or thermal oxidation, or an emerging alternative technology known as cryogenic‐compression and condensation combined with regenerative adsorption (C3–Technology). Of particular challenge to the off‐gas treatment selection process is the potential variety of chemical constituents and concentrations changing over time. Guidance is available regarding selection of off‐gas treatment technology (Air Force Center for Environmental Excellence, 1996; U.S. Environmental Protection Agency, 2006). However, there are common shortcomings of off‐gas treatment technology guidance and applications; practitioners have rarely considered sustainability and environmental impact of off‐gas treatment technology selection. This evaluation includes consideration of environmental sustainability in the selection of off‐gas treatment technologies and a region‐specific (Los Angeles, California) cost per pound and time of remediation comparisons between GAC, thermal oxidation, and C3–Technology. © 2008 Wiley Periodicals, Inc.     

重庆某铅污染场地稳定化修复技术研究

以重庆市某铅污染场地为研究对象,选用多种稳定化药剂对土壤开展稳定化修复技术研究,着重探讨了不同单一药剂与复配药剂对土壤铅浸出浓度的影响。实验结果表明:磷酸二氢钠(MSP)、磷酸氢二钠、磷酸钠和石灰4种无机药剂中MSP的稳定化修复效果最佳,且磷酸盐类的稳定化修复效果整体上优于石灰;MSP与少量有机药剂腐殖酸复配施用的稳定化修复效果优于单独施加MSP;在MSP投加比(与土壤的质量比)为5%、腐殖酸投加比为2%、养护时间为7 d的最优工艺条件下,土壤中铅的浸出浓度由41.70 mg/L降至0.16 mg/L,低于《生活垃圾填埋场污染控制标准》(GB 16889—2008)中规定的0.25 mg/L浓度限值。