多环芳烃污染土壤生物修复研究进展

多环芳烃 (Polycyclic aromatic hydrocarbons,PAHs) 是一类广泛分布于环境中的持久性污染物,结构稳定、难以降解,对生态环境和生物具有“三致”毒害性,其环境去除和修复备受关注。绿色、安全、经济的生物修复技术被广泛应用于PAHs污染土壤的修复。本文从土壤中PAHs的来源、迁移、归趋和污染水平总结了目前我国土壤多环芳烃污染的基本状况;归纳了具有PAHs降解作用的微生物、植物种类及机理;比较了微生物修复、植物修复和联合修复3类主要的生物修复技术。指出植物与微生物的互作机理的解析,抗逆菌株、植株的筛选与培育,实际应用的安全和效能评估应成为多环芳烃污染土壤修复领域未来的研究方向。     

In situ bioremediation of contaminated aquifers and subsurface soils

Bioremediation, the use of microorganisms to detoxify and degrade hazardous wastes, is an emerging in situ treatment technology for the remediation of contaminated aquifers and subsurface soils. This technology depends upon the alteration of the physical/chemical conditions in the subsurface environment to optimize microbiological activity. As such, successful bioremediation depends not only upon an understanding of microbial degradation processes, but also upon an understanding of the complex interactions that occur between the contaminants, the subsurface environment, and the indigenous microbial populations at each site. At present, these interactions are poorly understood. Site‐specific evaluation and design therefore are essential for bioremediation. In this paper, we review microbiological, hydrological, and geochemical factors that should be considered in evaluating the appropriateness of bioremediation for hazardous waste‐contaminated aquifers and subsurface soils.     

Bioventing in Shallow Tundra Overlying Permafrost

The purpose of this research was to investigate the feasibility of suction bioventing for treatment of contaminated tundra soil. Two laboratory-scale venting reactors were prepared with tundra from Arctic Alaska and operated, one for 32?d and the other for 52?d. For each rectangular reactor, suction was applied to a central well screened at mid-depth, while opposite ends of the reactor were screened to serve as air intake zones. The volume of liquid and gas recovered from the suction well was quantified daily. Numbers for heterotrophic organisms, pH, and dissolved organic carbon were quantified in the recovered liquid. The suction pump held a full vacuum (i.e., 101?kPa vac) for the duration of both experiments, indicating continuous obstruction of pneumatic and hydraulic conductivity. In both reactors, the soil in the proximity of the suction well separated from the bulk of the soil, precluding hydraulic communication. Furthermore, the soil nearest the well screen compacted, forming a barrier to appreciable pneumatic conductivity. At the end of operation, the soil was removed and sampled for moisture content, pH, and numbers of heterotrophic organisms at various locations. The results of this study showed that for suction bioventing to be successful in tundra, consolidation of the soil around the well screen must be prevented, as it will cause well isolation and limit both pneumatic and hydraulic conductivities.     

微生物修复石油烃土壤污染技术研究进展

随着人民生活水平的提高,环境保护问题愈发受到人们重视。其中石油烃的土壤污染因其持续时间长、污染去除难度大而受到广泛关注。在各类修复技术中,原位微生物修复强化技术因其成本较低、环境影响小、无二次污染、可原位修复的特点成为了当前的技术热门。文中综述了生物投加法、生物刺激法、联合修复法等原位微生物修复技术,并介绍了一些典型工程案例,为原位微生物修复强化技术的选择及工程应用提供了参考,并对未来原位微生物修复强化技术的研究重点进行了展望。     

Ex situ bioremediation of phenol contaminated soil using polymer beads

Polymer beads have been used to absorb high concentrations of phenol from soil decreasing the initial concentration of 2.3 g kg⁻¹ soil to 100 mg kg⁻¹ soil and achieving a phenol loading within the polymer beads of 27.5 mg phenol g⁻¹ beads. The phenol-loaded polymer beads were removed from the soil and placed in a bioreactor, which was then inoculated with a phenol-degrading microbial consortium. All of the phenol contained within the polymer beads was shown to desorb from the polymer matrix and was degraded by the microbial consortium. The beads were used again (twice) in a similar manner with no loss in performance.     

2020污染土壤的生物修复专刊序言

生物修复技术,作为可持续发展的重要方向,因其环境友好、高效且无二次污染并能从根本上解决土壤污染问题而受到关注,已经在土壤污染治理中得到了广泛的应用。为了梳理和凝练生物修复技术的发展状况,本专刊收录了该研究领域的16篇论文,分别从植物修复、微生物修复、联合修复、重金属吸收积累的相关分子机制、资源化再利用等方面,详细阐述生物修复技术的发展动态,展望未来的发展趋势,为促进生物修复技术的发展提供参考。     

Scale-up issues for in situ anaerobic tetrachloroethene bioremediation

For the full scale implementation of in situ anaerobic bioremediation of tetrachloroethene (PCE) in groundwater, the following issues must be addressed: which organic substrates at which concentration would be most effective in promoting dechlorination and are economical; how far the substrate, electron acceptor, and nutrients can be transported in the aquifer; and the placement of delivery and recovery wells for distributing these amendments. In a microcosm study, almost all of the tested inexpensive substrates supported reductive dechlorination of PCE through vinyl chloride (VC) under methanogenic conditions. A minimum of about 60 mg L⁻¹ of organic carbon was needed to dechlorinate 23 μM PCE with a single feeding. In a second microcosm study dechlorination stopped at 1,2-dichloroethene (DCE) in microcosms fed higher concentrations of several substrates. At the highest concentrations the substrates inhibited DCE production. Three field tracer tests were conducted to evaluate methods to distribute the amendments across the aquifer. The natural groundwater gradient is not sufficient to distribute substrate evenly. Groundwater injection at 60 times the natural flux rate increased the distribution of substrate. A mixing strategy of cross-gradient injection further increased the distribution of the substrate. Ammonia-nitrogen, sulfate, and phosphate were retarded relative to the substrate and inorganic tracer. Received 30 October 1995/ Accepted in revised form 07 June 1996     

A bioengineering system for in situ bioremediation of contaminated groundwater

Much of the past and current focus of bioremediation has been on laboratory studies of microbial processes. By necessity, early studies have ignored important field properties, parameters, and processes that control the ultimate success of in situ bioremediation of contaminated groundwater. This paper presents a bioengineering systems approach that examines the impact of some of these field variables on common bioremediation practices. Using simple systems, the niche of biostimulation is shown to be aquifers with high contaminant sorption. A novel gas-phase biostimulation filter and a novel resting-state bioaugmentation/biofilter approach which show promise for effective field implementation are discussed. Received 08 December 1995/ Accepted in revised form 30 July 1996     

Microbe-aliphatic hydrocarbon interactions in soil: implications for biodegradation and bioremediation

Aliphatic hydrocarbons make up a substantial portion of organic contamination in the terrestrial environment. However, most studies have focussed on the fate and behaviour of aromatic contaminants in soil. Despite structural differences between aromatic and aliphatic hydrocarbons, both classes of contaminants are subject to physicochemical processes, which can affect the degree of loss, sequestration and interaction with soil microflora. Given the nature of hydrocarbon contamination of soils and the importance of bioremediation strategies, understanding the fate and behaviour of aliphatic hydrocarbons is imperative, particularly microbe-contaminant interactions. Biodegradation by microbes is the key removal process of hydrocarbons in soils, which is controlled by hydrocarbon physicochemistry, environmental conditions, bioavailability and the presence of catabolically active microbes. Therefore, the aims of this review are (i) to consider the physicochemical properties of aliphatic hydrocarbons and highlight mechanisms controlling their fate and behaviour in soil; (ii) to discuss the bioavailability and bioaccessibility of aliphatic hydrocarbons in soil, with particular attention being paid to biodegradation, and (iii) to briefly consider bioremediation techniques that may be applied to remove aliphatic hydrocarbons from soil.     

A feasibility study for the in situ remediation of a former tank farm

A feasibility study of the in situ remediation of a former tank farm (on a petrol station) was made over a period of 150 days at 10 °C. The natural attenuation (which is a sum of the abiotic losses and the natural biodegradation by the indigenous soil microorganisms) and the effect of biostimulation by inorganic nutrient supply were investigated. The contamination was not homogeneously distributed in the seven soil samples investigated. Nutrient addition had no statistically significant effect on hydrocarbon decontamination. A remarkable part of the decontamination had to be attributed to natural attenuation. Soil microbial counts and CO₂ evolution indicated a negative effect of nutrition on the number of microbial hydrocarbon degraders and on soil microbial activity.     

五氯酚（PCP）污染土壤厌氧生物修复技术的初步研究

研究土壤泥浆反应器在投加厌氧颗粒污泥条件下修复PCP污染土壤的性能.结果表明,对PCP浓度30mg     

污染底泥原位覆盖技术综述

从污染底泥的危害入手,提出简单、有效且低成本的底泥原位覆盖技术.该技术将无污染的清洁材料铺盖到污染底泥上,通过覆盖材料对污染物的阻隔、稳固和吸附作用来有效控制底泥污染物.覆盖材料的粒径、比表面积和孔隙率、密度等特性关系到材料的吸附能力和对底泥污染物的阻隔和稳固作用,从而决定覆盖效果.选取覆盖材料及确定最佳覆盖厚度需要依据材料的这些特性.本文分析了原位覆盖技术的优缺点及适用条件和适用范围.介绍了几种常用的原位覆盖工程的施工方式及每种方式的优缺点,列举了大量的国内外覆盖工程实例,并就覆盖技术在我国良好的应用前景进行了分析.     

Application of Pneumatic Fracturing to Enhance In Situ Bioremediation

A field pilot demonstration integrating pneumatic fracturing and in situ bioremediation was carried out in a gasoline-contaminated, low permeability soil formation. A pneumatic fracturing system was used to enhance subsurface air flow and transport rates, as well as to deliver soil amendments directly to the indigenous microbial populations. An in situ bioremediation zone was established and operated for a period of 50 weeks, which included periodic subsurface injections of phosphate, nitrate, and ammonium salts. Off-gas data indicated the formation of a series of aerobic, denitrifying, and methanogenic microbial degradation zones. Based on soil samples recovered from the site, 79% of soil-phase benzene, toluene, and xylenes (BTX) was removed by the integrated technology. From mass balance calculations, accounting for all physical losses, it was estimated that 85% of the total mass of BTX removed (based on mean concentration levels) was attributable to biodegradation.     

我国污染土壤修复研究现状与展望

介绍了我国土壤污染的突出特点及其危害,回顾了污染土壤从清洁技术研究到物理、化学和生物修复研究的历程,总结了污染土壤修复取得的初步成果,提出了污染土壤修复的实质和系统技术方法。根据我国土壤污染的实际和修复需求,本文提出了当前本领域急需开展的研究内容,预测了污染土壤修复研究对环境科学相关学科的推动作用。     

石油污染土壤植物-微生物修复研究进展

依据国内外近10年来有关石油污染土壤生物修复研究的成果,综合阐述了石油污染土壤的植物修复、微生物修复及植物-微生物联合修复方法研究,重点讨论植物-微生物联合作用,主要包括植物根际微生物、根分泌物以及菌根对石油污染物降解的影响,提出了污染土壤原位修复中需要重视的问题.     

Effect of soil moisture on bioremediation of chlorophenol-contaminated soil

A chlorophenol-contaminated soil was tested for the biodegradability in a semi-pilot scale microcosm using indigenous microorganisms. More than 90% of 4-chlorophenol and 2,4,6-trichlorophenol, initially at 30 mg kg^–1, were removed within 60 days and 30 mg pentachlorophenol kg^–1 was completely degraded within 140 days. The chlorophenols were degraded more effectively under aerobic condition than under anaerobic condition. Soil moisture had a significant effect with the slowest degradation rate of chlorophenols at 25% in the range of 10–40% moisture content. At 25–40%, the rate of chlorophenol degradation was directly related to the soil moisture content, whereas at 10–25%, it was inversely related. Limited oxygen availability through soil agglomeration at 25% moisture content might decrease the degradation rate of chlorophenols.     

Feasibility of in situ implementation of vibrations to mobilize NAPL ganglia

A growing number of incidents of nonaqueous phase liquid (NAPL) spills in the recent past have warranted development of innovative and cost‐effective remediation technologies. Of particular concern is the entrapment of LNAPL (NAPL lighter than water) in the form of ganglia or blobs near the water table by virtue of strong capillary forces. The residual ganglia are the leftover component after pumping of free product and typically occupy 20 to 60% of the pore space. Mobilization of these ganglia would require unrealistically high hydraulic gradients and is often beyond the scope of pump‐and‐treat processes. This paper deals with the feasibility of in situ implementation of localized vibrations for controlled mobilization and collection of LNAPL ganglia. Specifically, the paper covers three components. First, the principles involved in soil‐water‐NAPL interactions under the influence of vibrations are discussed. The effects of vibrations on a soil‐NAPL‐water medium are postulated in terms of pore structure and relative density changes, changes in the permeability of the medium as a result of the changes in pore structure, and development of cyclic pore pressures. Second, results from bench‐scale experiments are presented that involved vibrating contaminated soils under the simultaneous influence of hydraulic gradients. A bench‐scale model consisting of a vibrator integrated with an injection and pumping system was found to be successful in these experiments. The results from the tests showed that up to 85% removal of ganglia can be achieved using this process. Third, the principles involved in the vibratory mobilization were applied to in situ conditions to develop a methodology to estimate the zone of influence of the process. The analogy between this process and an existing geotechnical process known as vibroflotation is exploited to demonstrate the methodology.     

Monitoring bioremediation in creosote-contaminated soils using chemical analysis and toxicity tests

Three soils with a history of creosote contamination (designated NB, TI and AC) were treated in bench-scale microcosms using conditions (nutrient amendment, moisture content and temperature) which had promoted mineralization of ¹⁴C-pyrene in a preliminary study. Bioremediation was monitored using the solid-phase Microtox test, seed germination and earthworm survival assays, SOS-chromotest, Toxi-chromotest and a red blood cell (RBC) haemolysis assay. Contaminant concentrations in the AC soil did not change after 150 days. Polycyclic aromatic hydrocarbon (PAH) concentrations decreased in the NB soil, and toxicity decreased overall according to the earthworm, seed germination and Microtox tests. Although total petroleum hydrocarbons (TPHs) in the TI soil were reduced following treatment, results of the earthworm, seed germination, RBC and Microtox tests suggested an initial increase in toxicity indicating that toxic intermediary metabolites may have formed during biodegradation. Toxicity testing results did not always correlate with contaminant concentrations, nor were the trends indicated by each test consistent for any one soil. Each test demonstrated a different capacity to detect reductions in soil contamination. Journal of Industrial Microbiology & Biotechnology (2000) 24, 132–139. Received 14 June 1999/ Accepted in revised form 12 November 1999