TOPSIS-Based Screening Method of Soil Remediation Technology for Contaminated Sites and its Application

A soil remediation technology screening system has not yet been established in China, and the existing supporting conditions for soil remediation technology cannot meet the supervision needs of contaminated sites’ remediation. Considering the soil remediation technology screening methods for contaminated sites in developed countries and the supervision requirements of contaminated sites in China, this article briefly introduces the main characteristics of decision-making methods, and the screening indices, including technical, economic, social, and environmental factors, are suggested. The technique for order performance by similarity to ideal solution (TOPSIS) was used to establish a screening process for soil remediation technology, and the analytic hierarchy process (AHP) method was utilized to obtain the weights of the screening indices. Tthe suggested screening method was then applied in a chromite ore-processing residue site in China, and suitable remediation technology (in-situ chemical reduction-oxidation) was proposed. The research results could provide scientific and technological support for the supervision of contaminated sites in China.     

土壤污染的生物修复技术研究进展

土壤污染是当今面临的一个重要环境问题。常规的土壤污染治理技术,如物理及化学治理技术,由于其技术要求高或经济成本昂贵,对土壤结构的扰动破坏严重,因而对其大规模的推广应用存在较大问题。而生物修复技术已被证明是一项非常有应用前景的新技术,成为土壤污染治理研究领域的一个热点,本文综述了近年来有机物及重金属土壤污染的生物修复机理和研究进展,并对其治理技术的最新研究动态、存在问题及发展趋势做了初步的讨论。     

花卉植物应用于污染土壤修复的可行性研究

植物修复是解决污染土壤问题的有效途径之一,而已报道的超积累植物的种类非常有限.如果能从物种繁多的花卉植物中筛选出修复植物,不但能够弥补这一不足,而且还能在美化环境的同时,产生一定的经济效益.从植物修复的重要性和修复植物的筛选出发,概括了修复植物的判断标准及基本特征.通过描述花卉植物资源及其在环境保护中的作用,列举花卉植物与其它植物相比的优势,分析花卉植物的耐性、积累性和修复类型,探讨花卉植物应用于污染土壤修复实践的可行性.从花卉中筛选超积累植物,将为污染土壤的修复工作提供的生物材料.     

某焦化场地土壤中多环芳烃分布的三维空间插值研究

为准确界定污染场地土壤中多环芳烃在3维条件下的污染分布范围和受污染土方量,选择我国某焦化污染场地苯并(a)芘分布为研究对象,对比研究Krig-3D、IDW-Shepard、IDW-(Franke/Nielson)以及Nearest Neighbor 4种3维插值方法对界定污染范围的不确定性影响。结果表明,不同3维插值模型计算结果差异较大,交叉验证结果显示Krig-3D插值模型插值精度最高,插值结果能较真实地反映场地实际污染情况。通过修复目标对比确定进一步表明,基于4种插值模型计算所得的污染土壤土方量分别为8.51×105、5.62×105、7.12×105、1.09×106m3,选择合理的插值模型将对预测污染范围的不确定性产生重要影响。研究结果对分析污染范围和修复治理过程土方量确定提供重要参考。     

Insights into phytoremediation solutions for environmental recovery

Our environment is contaminated with organic and inorganic compounds released by anthropogenic activities that cause negative impacts on biological productivity and ecosystem sustainability and place human health at risk. Within the available remediation technologies, phytoremediation has emerged with high potential due to its reduced environmental impacts and economic costs. The research into phytoremediation has developed through a wide array of approaches, which also pertains to its inherent interdisciplinary characteristics, towards enhancing the potential of the technology for application in the field. Numerous patents present molecular solutions through which plants can be engineered to display improvements in key characteristics, such as the tolerance, uptake and accumulation of contaminants. The manipulation of plant growth and of the physico-chemical characteristics of the contaminated environments in order to enhance the remediation potential has also been the focus of several issued patents. This review attempts to highlight the most relevant patented advances in phytoremediation and to emphasise recent research efforts through which this green technology might be expected to develop into a commercially competitive alternative to other remediation methods.     

镍污染土壤植物采矿技术关键过程及其研究进展

植物采矿是利用超积累植物高量吸收土壤中的重金属,并从中提取、冶炼金属产品,在修复污染土壤的同时实现金属的资源化。全世界广泛分布着自然风化的镍污染土壤,植物采矿因其重要的环境、生态及资源价值,被作为一种环境友好且具备经济效益的土壤修复技术,在此类地区具有广阔的应用前景。该植物采矿技术关键过程主要包括超积累植物镍高选择性根际环境响应、植物镍高效吸收转运以及生物质中镍高附加值资源化等过程。近30年,污染土壤中镍的植物采矿已经在美国、阿尔巴尼亚、马来西亚等多个国家进行了野外实践,取得了良好效果。然而,相关技术在我国的研究与应用仍然处于起步阶段。文中通过综述植物采矿技术的关键过程的研究进展,发现其中的瓶颈,为接下来植物采矿的科学研究和技术在全世界推广提供理论基础和技术指导。     

污染土壤修复标准建立的方法体系研究

近年来,污染土壤修复技术发展很快,而污染土壤修复标准的建立则相对迟缓．在我国,直至目前甚至还没有开展相应的研究．为了推进我国该领域的工作,对污染土壤修复标准建立的方法体系进行了阐述,并提出了建立污染土壤修复标准应同时考虑技术清洁水平、环境背景水平和法规可调控清洁水平等3个基本变量．而从技术清洁水平这一变量来讲,应该包括2个方面的内涵,一是污染土壤修复技术本身所能达到的清洁目标,二是现有分析技术发展所能确认的污染物最低限量目标,即仪器可检出水平．     

Genetic improvement of tree species for remediation of hazardous wastes

Summary Phytoremediation, using plants to clean up toxic wastes, is an idea that is attracting increasing attention from scientists, remediation engineers, and environmental professionals in government, industry, and universities. In situ remediation using plants has the potential to be less expensive than current technologies and to simultaneously initiate both detoxification of hazardous waste and site restoration. The perennial habit, extensive root mass, and large transpirational rates give trees advantages over other plants for use in remediation. Trees are already used for wastewater clean-up, for site stabilization, and as barriers to subsurface flow of contaminated groundwater. Clonal propagation and the genetic tools of both classical breeding and genetic engineering exist for a number of both angiosperm and gymnosperm species, opening the door to creation of tree “remediation” cultivars. Work is underway to screen tree species for their ability to tolerate, take up, translocate, sequester, and degrade organic compounds and heavy metal ions. Both an indirect approach to remediation, through enhancing rhizosphere degradation of pollutants by engineering larger root masses in trees usingAgrobacterium rhizogenes, and a direct approach to remediation, through transformation of trees with bacterial genes known to initiate the mineralization of halogenated phenolic compounds and trichloroethylene are reviewed. Presented in the Session-in-Depth Bioremediation through Biotechnological Means at the 1993 Congress on Cell and Tissue Culture, San Diego, CA, June 5–9, 1993.     

Environmental Risk Controllability and Management of VOCs during Remediation of Contaminated Sites

The environmental risk controllability assessment system and its method of controlling volatile organic compounds (VOCs) during remediation of contaminated sites are established in this article based on soil vapor extraction (SVE) technology. According to the properties of VOCs and the technical and operational characteristics of the site remediation process, the environmental risk controllability index system includes environmental risk identification, risk source analysis, and risk assessment. Environmental risk management during site remediation was focused on technical control methods and engineering control technologies. Specifically, acceptance based on risk management was suitable for low-risk levels such as RRI3 and RRI4. Furthermore, control methods for high-level risk (RRI1 or RRI2) could be developed along with transformation and control, combined with the necessary emergency risk plan.     

Effect of a polycyclic aromatic hydrocarbon on the phytoremediation of zinc by two plant species (Brassica juncea and Festuca arundinacea)

The redevelopment of contaminated land is becoming increasingly necessary under sustainable- development legislation; however, many of the contaminated sites are "orphan" sites and therefore require a low-cost remediation technology. These sites often contain a cocktail of pollutants including organics and inorganics. Phytoremediation provides a possible solution, but there is little information available on the tolerance of plant species to multiple pollutants and their ability to remediate in mixed-contaminant soils. The effect of a polycyclic aromatic hydrocarbon (pyrene) in soil upon the remediation of zinc by Brassica juncea and Festuca arundinacea was investigated under normal climatic conditions in the United Kingdom. Zinc was effectively removed from mixed-contaminant soils in the presence of both species, in comparison to a control treatment. Both species accumulated zinc in plant tissues in the presence of pyrene, but the growth of B. juncea was significantly reduced when zinc and pyrene were supplied in combination. Zinc was predominantly associated with root tissues for F. arundinacea, whereas B. juncea contained higher concentrations in shoot tissues. F. arundinacea provides a possible species to be used for the phytoremediation of brownfield sites, but further research is required to determine a range of species that may be used and their applicability to different contaminants.     

建立污染土壤修复标准的探讨

随着污染土壤修复技术的发展和污染土壤修复环境工程的实施,污染土壤修复标准的建立已成为检验污染土壤修复工程效果的瓶颈.我国现行的土壤环境质量标准已不能适应污染土壤修复效果评判的需要.本文在分析我国土壤环境质量标准不足的基础上,结合一些发达国家土壤修复标准以及我国土壤污染实际情况,提出建立污染土壤修复标准应从污染物的选择、分析检测方法、修复标准的分类、对地下水的保护和生态毒理学评价方面综合考虑.     

A decision framework for selecting remediation technologies at hydrocarbon‐contaminated sites

A variety of remediation technologies are available to address hydrocarbon contamination, including free product recovery, soil venting, air sparging, groundwater recovery and treatment, and in situ bioremediation. These technologies address hydrocarbon contamination distributed between free, adsorbed, and dissolved phases in both the vadose and saturated zones. Selection of appropriate technologies is dependent on a number of factors, including contaminants, site‐specific characteristics, clean‐up goals, technology feasibility, cost, and regulatory and time requirements. This article describes a decision framework for selecting appropriate remediation technologies at hydrocarbon‐contaminated sites in a structured and tiered manner. Decision modules include (1) site characterization and product recovery; (2) vadosezone treatment: soil venting, bioremediation, and excavation; (3) saturated zone treatment: sparging, bioremediation, groundwater recovery, and excavation; and (4) groundwater treatment: carbon, air stripping, advanced oxidation, and bioreactors. Selection criteria for treatment technologies that address vadose‐ and saturated‐zone soils, as well as recovered groundwater, are described. The decision framework provides a systematic process to formulate solutions to complex problems and documents the rationale for selecting remediation systems designed to achieve closure at hydrocarbon‐contaminated sites.     

高生物量经济植物修复重金属污染土壤研究进展

植物修复是重金属污染土壤修复的重要方法之一。利用高生物量经济植物修复重金属污染土壤,能够兼顾生态和经济效益,具有很大的应用前景。本文系统分析了植物修复现状及存在的问题,提出利用高生物量经济植物修复重金属污染土壤的优势,总结了近年来利用高生物量经济植物吸收重金属的研究进展,探讨了改善高生物量经济植物修复重金属污染土壤效率的方法,以期为提高植物修复经济效益、促进植物修复广泛应用提供参考。     

我国土壤重金属污染植物吸取修复研究进展

我国从上世纪90年代中后期开始土壤重金属（含类金属砷）污染的植物吸取修复研究及技术探索,先后发现了一批具有较高研究价值和应用前景的铜、砷、镉、锰等重金属的积累或超积累植物,并从重金属耐性和超积累生理机制、植物吸取修复的根际过程与机制、吸取修复强化措施和修复植物处置与资源化利用等方面进行了研究,同时开展了植物吸取修复技术的示范与应用,已有一些较成功的植物修复工程应用案例,使我国重金属污染土壤植物修复技术,尤其是植物吸取修复技术在国际上产生了较强的影响力。本文就近年来我国土壤重金属污染植物吸取修复研究进展进行了综述,并对今后的发展趋势进行了展望。     

污染土壤淋洗修复技术研究进展

土壤淋洗修复技术是一种行之有效的污染土壤治理技术,适合于快速修复受高浓度重金属和有机物污染土壤与沉积物。本文综述了土壤淋洗修复技术的特点、技术流程、土壤淋洗剂的研究与应用进展,指出异位土壤淋洗修复技术因修复效果稳定,易于实现系统控制和废弃物减量化等优点而具有更广阔的应用前景,天然螯合剂和生物表面活性剂等环境友好型淋洗剂正逐渐取代人工螯合剂和化学表面活性剂成为土壤淋洗剂研究的主流方向,而现代超分子化学的引入和发展有可能对复合污染土壤的高效淋洗修复研究产生新的影响。     

土壤氟形态与氟污染土壤修复

我国土壤氟污染问题严峻,给部分地区人体健康和生态安全造成严重威胁,但土壤氟污染与防治问题仍没有受到人们的广泛关注.本文概述了土壤中氟的存在形态以及发生的主要化学反应,综述了近年来国内外有关氟污染土壤修复的研究进展,提出了今后氟污染土壤修复的研究方向,以期为氟污染土壤的修复提供借鉴和参考.土壤中氟主要分为5种形态,其中90%以上以残渣态存在,土壤溶液中的氟主要发生沉淀-溶解、络合-解离和吸附-解吸等反应来维持水-土系统中的氟平衡.目前,氟污染土壤修复技术研究主要集中在化学固定修复技术、化学淋洗技术、电动修复技术以及植物修复技术.今后需要重点研究氟在土壤中的赋存形态及其影响因子,筛选功能微生物和植物,开发联合修复技术以修复氟污染土壤.     

In-Situ Remediation of TCE in Clayey Soils

The remediation of solvent contaminated low permeable soils poses a significant problem for many facilities. A consortium of industrial partners (Monsanto, DuPont and General Electric), the USEPA and the DOE jointly developed a technology that integrates electrokinetics with in-situ treatment of chlorinated organics to address this problem. The process, called Lasagna^TM, utilizes a DC electric field to move pore water and contaminants uniformly through the soil mass to treatment zones emplaced within the contaminated area. The emplacement is performed using common piling technologies and results in little or no wastes. The treatment materials emplaced are typically iron, coke and kaolin. After two in-field demonstrations, a full-scale Lasagna remediation system was implemented at the DOE facility in Paducah, KY for the remediation of TCE contaminated clay soils. The system was installed and operated over a two-year period. The process was shut down in December 2001 after meeting the cleanup target of 5.6 mg/kg specified by the Record of Decision (ROD) for the site. The final results show an average TCE concentration of 0.38 mg/kg.     

The impact of uncertainty on phytoremediation project costs

Pollution of the environment by metals and organic contaminants is an intractable global problem, with cleanup costs running into billions of dollars using current engineering technologies. The availability of alternative, cheap and effective technologies would significantly improve the prospects of cleaning-up metal contaminated sites. Phytoremediation has been proposed as an economical and 'green' method of exploiting plants to extract or degrade the contaminants in the soil. To date, the majority of phytoremediation efforts have been directed at leaping the biological biochemical and agronomic hurdles to deliver a working technology, with scant attention to the economic outlook other than simple estimates of the cost advantages ofphytoremediation over other techniques. In this paper we use a deterministic actauarial model to show that uncertainty in project success (the possibility that full clean up may not be realized) may significantly increase the perceived costs of remediation works for decision-makers.     

The Phytomanagement of Trace Elements in Soil

Trace elements (TEs) occur at low concentrations (<1000 mg kg ^?1) in organisms, yet they have a large biological effect, both as essential nutrients and environmental contaminants. Phytomanagement describes the manipulation of soil-plant systems to affect the fluxes of TEs in the environment with the goal of remediating contaminated soils, recovering valuable metals, or increasing micronutrient concentrations in crops. Phytomanagement includes all biological, chemical, and physical technologies employed on a vegetated site. Successful phytomanagement should either cost less than other remediation or fortification technologies, or be a profitable operation, by producing valuable plant biomass products. This may include bioenergy or timber production on contaminated land, a practice that does not reduce food production. We review the components of phytomanagement and the underlying biogeochemical processes, with a view to elucidating situations where this technology may be successfully applied and identifying future research needs. Many full-scale operations have proved the efficacy of plants to reduce contaminant mobility in soils (phytostabilization), particularly when used in combination with other technologies. As a stand-alone technology, the oft-touted use of plants to extract TEs from contaminated soils (phytoextraction) or low-grade ore bodies (phytomining) is unsuitable for most, if not all, sites due to low-extraction rates and problems caused by site heterogeneity, the limited rooting depth of plants and the presence of contaminant mixtures. Unsubstantiated claims about phytoextraction have tarnished the reputation of all “phyto” technologies. Nevertheless, phytoextraction, as part of a larger environmental toolkit, has a role in phytomanagement. The growth, or lack thereof, of profitable companies that provide phytomanagement will indicate its value. A critical knowledge gap in phytomanagement is the integration of the processes that affect plant–TE interactions and the biophysical processes affecting TE fluxes in the root zone, especially the effect of roots on contaminant fluxes.     

A comprehensive overview of elements in bioremediation

Sustainable development requires the development and promotion of environmental management and a constant search for green technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. Bioremediation is an increasingly popular alternative to conventional methods for treating waste compounds and media with the possibility to degrade contaminants using natural microbial activity mediated by different consortia of microbial strains. Many studies about bioremediation have been reported and the scientific literature has revealed the progressive emergence of various bioremediation techniques. In this review, we discuss the various in situ and ex situ bioremediation techniques and elaborate on the anaerobic digestion technology, phytoremediation, hyperaccumulation, composting and biosorption for their effectiveness in the biotreatment, stabilization and eventually overall remediation of contaminated strata and environments. The review ends with a note on the recent advances genetic engineering and nanotechnology have had in improving bioremediation. Case studies have also been extensively revisited to support the discussions on biosorption of heavy metals, gene probes used in molecular diagnostics, bioremediation studies of contaminants in vadose soils, bioremediation of oil contaminated soils, bioremediation of contaminants from mining sites, air sparging, slurry phase bioremediation, phytoremediation studies for pollutants and heavy metal hyperaccumulators, and vermicomposting.