生物表面活性剂在石油污染土壤生物预制床修复中的应用研究

通过拮抗实验选用高效降解菌B2020,真菌F2006、F2008、F6、F9904、F9902进行互配,对生物预制床中的高凝油、稠油、特稠油、稀油进行处理,发现生物表面活性剂对石油的降解有促进降解作用,在90~120d降解率提高较大。如果空气温度较高,无论是否施用生物表面活性剂,石油的降解速率都得到了大幅度提高,平均提高幅度为15%左右。因此,生物修复应尽量选择在温度较高的季节进行。     

An Improved Gravimetric Method to Determine Total Petroleum Hydrocarbons in Contaminated Soils

A gravimetric method to determine heavy fractions of total petroleum hydrocarbons (TPH) in soils is reported. The method was adapted and calibrated by modifying previous standard methods published, incorporating energy and cost savings where possible. Artificially contaminated soils with different organic matter content, and aged in stationary mode for a period of 8 months were used for calibration. Insufficient solvent evaporation was identified as the most prevalent and largest positive interference in the gravimetric detection. To overcome this, while minimizing the need for heating, a combination of three 10-min rotary evaporator steps and 30 min of vacuum in a desiccator were applied, for a total solvent volume of 60 ml. Hexane was chosen as the extraction solvent and a 40–60 min treatment in an ultrasound bath of 260 W was found suitable to extract 80–95% of TPH extracted by the Soxhlet method. Finally, the use of silica gel for cleanup of co-extracted natural organic matter was found unnecessary, because of the low amounts co-extracted for soils with up to 5% organic carbon, and because the chemical nature of the co-extracted organic matter prevents its selective adsorption to silica.     

Surfactant-Enhanced Soil Washing for Removal of Petroleum Hydrocarbons from Contaminated Soils: A Review

An increase in energy demand leads to further exploration, transportation, and utilization of petroleum, which creates severe soil contamination because of recurrent accidents and oil spills. Remediation of these contaminated soils is challenging. Among many treatment methods practiced for remediation of petroleum-contaminated soils, surfactant-enhanced soil washing has been widely practiced as a preferred treatment option, as it is a fast and environmentally accepted method. In this paper, we review research undertaken on various anionic, nonionic, cationic, biological, and mixed surfactants for the remediation of petroleum hydrocarbon-contaminated soils. Upcoming surfactants like gemini and switchable surfactants are summarized. We assess the challenges and opportunities of in-situ and ex-situ soil washing, the mechanisms of surfactant-enhanced soil washing, and the criteria to follow for surfactant selection. Furthermore, we briefly discuss the operational and environmental factors affecting soil washing efficiency and soil and surfactant properties affecting surfactant adsorption. We also describe the advantages of coupling soil washing with effluent treatment and surfactant reuse challenges and opportunities. Moreover, challenges and possible new directions for future research on surfactant-enhanced soil washing are proposed.     

石油污染土壤的生物修复研究进展

对于石油污染土壤的修复,其生物修复具有环境友好、费用较低等特点,是最具应用前景的土壤修复技术。本文较全面地介绍了石油污染土壤生物修复的影响因素、石油污染土壤的生物修复技术,并对该领域今后的研究重点进行了展望。     

Biodegradation and Phytotoxicity of Biodiesel,Diesel, and Petroleum in Soil

Biogas must be pretreated before its use; thus, both physical and chemical methods have been implemented to remove the fuel’s principal pollutants (CO₂ and H₂S). Additional removal methods that use microorganisms’ biological processes to eliminate pollutants have also emerged. A selection was made from six bacterial isolates to obtain consortia that removed CO₂ and eventually H₂S through the enrichment of cultures and the construction of clone libraries of gene 16S ribosomal DNA (rDNA). The results indicate that the principal differences between consortia were determined in the culture medium. C5 and C6 consortia had photosynthetic biomass 1.42 and 1.52 μg/ml, respectively, and concentration of dissolved CO₂ 100.6 and 99.1 mg/l, respectively. The clone libraries showed that Rhodopseudomonas sp. had percentages 46.6, 42.5, and 86.8 % in C4, C5, and C6, respectively; Xanthobacter sp., 24.5 %, Castellaniella sp., 18 % in C5, and Sphingobium sp., 39.2 % in C4.     

生物修复石油污染土壤研究现状

石油污染土壤的生物修复方法具有操作简便、费用低、对周围环境污染小、修复效率高等优点,应用前景广阔。从石油污染土壤生物修复过程中修复生物的选择、修复条件的优化、修复效果的评价等方面对近年来生物修复技术的研究进展进行了综述。为推动该方法的广泛应用,还应深入探究降解微生物之间的拮抗和协同机制、进一步降低修复成本、进一步完善修复评价标准,加强重石油污染土壤和特殊环境下石油污染土壤的治理研究,开展复合污染(如石油污染和重金属污染)土壤的修复研究。     

Extractability and Subsequent Biodegradation of PAHs from Contaminated Soil

The biodegradation of polyaromatic hydrocarbons (PAHs) has been well documented; however, the biodegradation of PAHs in contaminated soil has proved to be problematic. Sorption of PAHs to soil over time can significantly decrease their availability for extraction much less than for biodegradation. In this study the ability of various organic solvents to extract PAHs from coal tar-contaminated soil obtained from former manufactured gas plant (MGP) sites was investigated. Solvents investigated included acetone/hexane, dichloromethane, ethanol, methanol, toluene, and water. The extraction of MGP soils with solvents was investigated using soxhlet extraction, multiple soxhlet extractions, sonication, and brief agitation at ambient temperature with a range of solvent concentrations. Of particular interest was the documentation of the recalcitrance of PAHs in weathered MGP soils to extraction and to bioremediation, as well as to demonstrate the ease with which PAHs extracted from these soils can be biodegraded. The efficiency of extraction of PAHs from MGP soils was found to be more dependent upon the choice of solvent. The environmentally-benign solvent ethanol, was shown to be equal to if not better than acetone/hexane (the EPA recommended solvent) for the extraction of PAHs from MGP soils, brief contact/agitation times (minutes) using small quantities of ethanol (2 volumes or less) can achieve nearly quantitative extraction of PAHs from MGP soils. Moreover aqueous slurries of an MGP soils experienced less than 10% biodegradation of PAHs in 14 days while in the same period about 95% biodegradation was acieved using PAHs extracted from this soil by ethanol and subsequently added to aqueous bacterial suspensions.     

一株副球菌对污染土壤中多环芳烃的降解研究

从受多环芳烃(PAHs)长期污染的土壤中分离到一株降解PAHs的噬氨副球菌(Paracoccus aminovorans)HPD-2.使用HPD-2的菌液对PAHs污染的土壤进行了2周的生物降解试验,结果表明加入HPD-2能够明显提高土壤中PAHs的降解率.加菌土壤中PAHs的总去除率为22.9%,PAHs各组分的降解率在19.5% ～ 36.2% 之间.其中三环PAHs的降解率最高(36.1%),五环次之(26.0%),四环的最低(20.9%).对土壤微生物的计数结果发现,HPD-2的加入显著提高了土壤中细菌的数量,而对放线菌和真菌的影响不明显.PCR-DGGE分析结果表明,降解过程中HPD-2可能成为土壤中的优势菌.以上结果表明该菌株在PAHs污染土壤的生物降解中具有较好的应用前景.     

Transformation of Petroleum Saturated Hydrocarbons during Soil Bioremediation Experiments

This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pan?evo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P₁–P₁₂ samples). Organic substance was extracted by Soxhlet’s method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MS-chromatogram revealed only marginal amounts of pristane and phytane in sample P₁. Pristane and phytane occurred in sample P₈, and in even higher quantities in the final sample P_12. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri- and tetracyclic terpanes. In the initial sample P₁ the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P₈ and P₁₂ because of the reduced concentration. The observed changes in the alkane fractions’ compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra- and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed.     

Heritability of Phytoremediation Potential for the Alfalfa CultivarRiley in Petroleum Contaminated Soil

Petroleum contamination poses a significant threat to environmental ecosystems world-wide. Phytoremediation can be used to enhance degradation of petroleum contaminants in soil. However, selection of plants for phytoremediation has proven to be complicated. This research examines the heritability of the alfalfa cultivar Riley for phytoremediation based on parental total petroleum hydrocarbon (TPH) degradation after twelve months of growth. Traits other than degradation potential, such as root and shoot yield, height, and maturity, were examined for use as selection traits. Riley showed moderate to low heritability that suggests the possibility of breeding for phytoremediation efficiency. In addition, root and shoot yield were found to correlate to TPH degradation. Crosses in which the female parent was typically associated with low TPH dissipation yielded progeny that were high efficiency TPH degraders.     

Field-Scale Assessment of Phytotreatment of Soil Contaminated with Weathered Hydrocarbons and Heavy Metals (9 pp)

Background, Aim and Scope   Phytoremediation is a remediation method which uses plants to remove, contain or detoxify environmental contaminants. Phytoremediation has successfully been applied for the removal of fresh hydrocarbon contamination, but removal of aged hydrocarbons has proven more difficult. Biodegradation of hydrocarbons in the subsurface can be enhanced by the presence of plant roots, i.e. the rhizosphere effect. Phytostabilization reduces heavy metal availability via immobilization in the rhizosphere. Soils contaminated by both hydrocarbons and heavy metals are abundant and may be difficult to treat. Heavy metal toxicity can inhibit the activity of hydrocarbon-degrading microorganisms and decrease the metabolic diversity of soil bacteria. In this experiment, weathered hydrocarbon- and heavy metal- contaminated soil was treated using phytoremediation in a 39- month field study in attempts to achieve both hydrocarbon removal and heavy metal stabilization. Materials and Methods: A combination of hydrocarbon degradation and heavy metal stabilization was evaluated in a field-scale phytoremediation study of weathered contaminants. Soil had been contaminated over several years with hydrocarbons (11400±4300 mg kg dry soil)-1 and heavy metals from bus maintenance activities and was geologically characterized as till. Concentrations of soil copper, lead and zinc were 170±50 mgkg-1, 1100±1500 mg kg-1 and 390±340 mg kg-1, respectively. The effect of contaminants, plant species and soil amendment (NPK fertilizer or biowaste compost) on metabolic activity of soil microbiota was determined. Phytostabilization performance was investigated by analyses of metal concentrations in plants, soil and site leachate as well as acute toxicity to Vibrio fischeri and Enchtraeus albidus. Results: Over 39 months hydrocarbon concentrations did not decrease significantly (P=0.05) in non-amended soil, although 30% of initial hydrocarbon concentrations were removed by the last four months of study. In soil amended with NPK fertilizer and municipal biowaste compost, 65 % and 60 % of hydrocarbons were removed, respectively. The soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Compost addition resulted in a slight increase in enzymatic activities. Diesel fuel utilization potential in Biolog MT2 plates inoculated with a soil suspension was enhanced by both compost and NPK compared to non-amended soil. Soil toxicity to V. fischeri and E. albidus was low. The leachate was not toxic to V. fischeri. Pine (Pinus sylvestris), poplar (Populus deltoides x Wettsteinii), grasses and clover (Trifolium repens) survived to varying degrees in the contaminated soil. All plants suffered from phytotoxicity symptoms and some trees died during the study period. Plants formed a dense cover over the compost-amended soil, whereas non-amended soil had areas devoid of vegetation throughout the study. Vegetation coverage in the NPK-amended quarter was about 50 % after the first four months of study, but increased gradually to 100 %. Heavy metals did not accumulate in plant tissue. Discussion: Removal of hydrocarbons from weathered unfertilized hydrocarbon-contaminated soil was not statistically significant despite the presence of a viable hydrocarbon-degrading microbial community. This effect is attributed to soil heterogeneity and low bioavailability of hydrocarbons. Hydrocarbon concentrations were not reduced to the desired level, i.e., 1500 mg hydrocarbons (kg of dry soil)-1, in any treatment. . The presence of clay minerals and organic matter within the compost may have limited heavy metal transfer to leachate and plant tissue. Conclusions: Weathered hydrocarbons were partly decomposed in soil fertilized with NPK fertilizer or biowaste compost, but not from unfertilized soil. The active hydrocarbon-degrading microbiota and low toxicity of soil to V. fischeri and E. albidus indicates low availability of contaminants to microorganisms. Despite high heavy metal concentrations, the soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Heavy metals did not accumulate in test plants. Pine and poplar suffered from phytotoxicity symptoms in the soil and could not enhance hydrocarbon removal in compost-amended soil. Compost addition combined with a grass and legume crop is suggested for stabilization of combined hydrocarbon- and metal-contaminated soil. Recommendations and Perspectives: Both compost and NPK fertilizers can be used to enhance phytoremediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals; however, compost addition is recommended since it enables greater vegetative coverage. This in turn may decrease heavy metal mobility. Phytoremediation can be used for remediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals. However, phytoremediation of weathered contaminants requires extended periods of time; thus, other remediation methods should be considered in the event of soil contamination posing an immediate public health and/or environmental threat.     

植物间作下根际微生物和土壤酶与土壤多氯联苯（PCB）降解的关系

以大豆、黑麦草和南瓜为材料,采用盆栽实验,研究了3种植物的单作和相互间作的不同种植方式对多氯联苯污染土壤的根际修复效应与机理。结果表明：（1）PCB去除率与土壤蛋白酶和磷酸酶活性均呈极显著正相关关系,相关系数分别为0.878和0.929（P〈0.01）,推测这两类酶可能参与了PCB的生物降解过程;（2）PCB去除率与土壤真菌密度呈显著相关（r=0.797）,而PCB去除率与土壤细菌及放线菌密度相关不显著;（3）在本实验条件下,微生物因素对土壤PCB的降解起主导作用,非灭菌土处理的土壤PCB去除率比灭菌土相对应的对照高出17.7%~30.75%;（4）根系分泌物能显著强化微生物的降解功能,添加黑麦草和大豆根系分泌物处理的土壤PCB去除率分别比只加营养液的对照高出21.4%和24.9%。     

Finger-Printing Biodegradation of Petroleum Contamination in Shallow Groundwater and Soil System Using Hydro-bio-geochemical Markers and Modelling Support

This study was conducted to determine the potential of in situ biodegradation and identify the geochemical and microbial processes of the petroleum-contaminated subsurface environment using integrated hydro-bio-geochemical markers so that the risk of contamination to subsurface environment can be better understood. The contamination process and corresponding bio-geo-chemistry were analysed in parallel with geochemical and multi-variant statistical modelling at a petroleum-contaminated site in the northeast China. The total petroleum hydrocarbon analysed in the monitoring wells and soil profile demonstrated heavy contamination with potential risk to human health and eco-environment. Further detailed analysis of petroleum fractions revealed a clear spatial variation of organic compositions in groundwater. It was evident that biodegradation and preferential biodegradability contributed considerably to the fraction distribution pattern, which can also be implicated by carbon and microbial respiration in the subsurface environment. The steady decrease in SO ₄ ^2- concentration, detection of S^2-, and increase in pH and alkalinity (HCO ₃ ^- ) in groundwater during the monitoring period demonstrated that sulphate reduction was the dominant biodegradation process in most contaminated zones. The results of statistical analysis further suggested that the hydro-geochemical environment was mainly controlled by the regional hydro-geochemical and sulphate reduction process associated closely with the total petroleum hydrocarbon. Knowledge from the comprehensive study provides useful insight on fate, transport and risk assessment of the petroleum contaminants in the shallow subsurface environment.     

狗牙根对石油污染土壤的修复效果研究

为了研究狗牙根对中原油田地区土壤石油污染的修复效果,通过盆栽实验,设置4组处理,对照组(即不种植狗牙根组)、种植狗牙根组、种植狗牙根并添加尿素组、种植狗牙根并添加有机肥组,分别在15,30,60,90,120 d取样分析.结果表明:经过120 d后,对照组的土壤石油污染去除率为25.40%;种植狗牙根组的土壤石油污染去除率为58.67%,是对照组的2.3倍;添加尿素可以有效的增加狗牙根对石油的去除率,当尿素:土为1:2000时,石油污染去除率达到69.43%;土壤石油污染去除率随着有机肥的增加而增加,施加有机肥水平为12 g/kg时,土壤石油污染去除率达到83.97%,是狗牙根组去除率的1.4倍.因此,种植狗牙根对土壤石油污染修复有较好的作用,合理施肥对狗牙根修复土壤石油污染影响显著.     

盐渍化土壤中土著菌的石油烃降解潜力研究

自盐渍化地区（黄河三角洲）采集4种不同石油污染程度的土壤样品,从中筛选出高效降解石油烃的4个菌系和8个单菌株。分别以原油、柴油、烷烃和多环芳烃（PAHs）为底物进行培养,测定降解菌的生物量和降解率,研究其对不同底物的耐受浓度和降解潜力。结果表明,获得的石油烃降解菌为轻度嗜盐菌;不同菌株对不同底物的耐受浓度不同,混合菌系对不同底物的降解能力强于单菌株,对单一组分底物的降解优于复杂组分的底物;单菌株I-2、3、5、7能较好地降解PAHs并且对原油的降解能力高于柴油,单菌株I-1、4、6、8能够利用烷烃且对柴油的降解能力要比原油高;降解菌对柴油和原油的最高降解率分别可达78．4％和70．7％,对正十六烷和菲的生物降解率分别高达87．7％和88．1％,表现出较强的降解能力。研究结果表明黄河三角洲盐渍化土壤中土著菌对石油烃污染土壤具有较强的牛物修复潜力。     

Fingerprinting Hydrocarbons in a Contaminated Soil from an Italian Natural Reserve and Assessment of the Performance of a Low-Impact Bioremediation Approach

An environmentally friendly procedure suitable to restore a protected area was evaluated at laboratory scale. Soil contaminated by high molecular weight (C > 10) aliphatic hydrocarbons and by chromium was withdrawn from the study site and a qualitative study of soil hydrocarbon components was first performed in order to assess the potential source of contamination. To this aim, a number of characteristic diagnostic ratios of hydrocarbon components were derived by processing chromatographic data, and were used as indicators for distinguishing anthropogenic from natural hydrocarbons. Then, the efficiency of landfarming for soil remediation was tested by comparing the effect of a few selected amendments and by monitoring the fate of chromium. Soil microbial abundance and activity were also evaluated. Results showed that soil hydrocarbons were mainly of anthropogenic origin and land treatment allowed effective degradation by native microbial populations even in the absence of amendments. The investigated procedures had no effect on the mobilisation of chromium that remained in its stable form of Cr(III). Conventional land treatment may therefore be an effective and safe procedure for the removal of hydrocarbons even in the presence of chromium, and may be applied to areas where low-impact procedures are strictly required.     

热活化过硫酸盐氧化污染土壤中的石油烃

石油的开采、运输、储存和使用等过程会导致一些土壤受到石油烃的污染。土壤中的石油烃会对生态安全和人类健康造成潜在危害，因此需要开展土壤修复。本研究采用热活化过硫酸钠氧化处理污染土壤中的石油烃，考察了氧化剂剂量和超声结合热活化对石油烃去除效率的影响，并对石油烃氧化产物以及氧化后土壤理化性质进行了分析。结果表明，当过硫酸钠的用量为2.4 mmol/g土壤时，石油烃的含量从3 800 mg/kg降至1 175 mg/kg，石油烃的去除效率可以达到69%。石油烃的去除效率随着氧化剂增加呈上升趋势。但当氧化剂的剂量超过2.4 mmol/g土壤时，石油烃的去除效率不再增加。使用超声结合热活化，石油烃的去除效率可以进一步提高。过硫酸盐氧化会使土壤p H显著下降，造成土壤酸化。气相色谱质谱(GC/MS)和傅里叶变换红外光谱(FTIR)分析表明石油烃氧化后可能会生成一些醇和羧酸类含氧产物。石油烃和土壤有机质被氧化成极性小分子更易进入水相，导致水中总有机碳(TOC)含量从52.4 mg/kg增加至79.8 mg/kg。扫描电镜和粒度分析表明氧化处理会改变土壤形貌，使土壤的粒径变小。氧化导致土壤的碳、氢含量减...     

表面活性剂强化过硫酸钠氧化修复石油烃污染土壤

为了提升石油烃污染土壤的修复效率，考察了不同表面活性剂(吐温-80 (Tw-80)、曲拉通X 100 (TX 100)、十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS))对过硫酸钠氧化土壤中石油烃的强化效果，并分析了表面活性剂SDS强化修复效果较优的原因。土壤中石油烃的去除率遵循如下趋势：SDS>SDBS>TX 100>Tw-80。SDS强化修复效果较优可能与其在土壤中吸附量较小对石油烃的增溶效果好、上清液中过渡态金属含量较高及对过硫酸钠分解消耗少有关。通过优化反应参数，可以进一步提高SDS强化过硫酸钠氧化修复石油烃污染土壤的效率，对采自武汉和盘锦的两种石油烃污染土壤都具有较好的修复效果。