有机污染土壤电动-微生物修复过程中的影响因素及优化措施

Influencing Factors and Optimization Measures in the Electro-bioremediation of Organic Contaminated Soil

生物修复技术因其费用低、对环境不产生二次污染而被视为是一项具有广阔发展前景的技术。然而,一些强疏水性的有机污染物,生物可利用性很差,严重阻碍了其生物降解效率。电动与微生物联合修复技术(电动-微生物修复),在顽固性有机污染物的去除方面表现出巨大潜力。电场的施加可向土壤中分散外源物质、营养物质和微生物;或通过增强土壤中有机污染物与降解菌的传质过程,提高难降解有机物的生物可利用性;还可诱使土壤中的污染物产生电化学反应,增强污染物的去除效果。文章对有机污染土壤的电动-微生物修复过程的影响因素及优化措施进行了综述。文章认为,影响电动-微生物修复效率的因素主要有电场强度、污染物的生物可利用性、污染物结构和性质、微生物种群以及环境因素(如土壤pH值、土壤类型、营养物质、含水量等)。因此,在实施修复的过程中应根据污染场址的电化学特性选择合适的电流或电压梯度;另外,可通过施加表面活性剂、助溶剂或螯合剂,构建微生物群落,以及优化土壤环境条件,如调整土壤pH、提供营养物质、电子受体、共代谢基质等方式优化有机污染土壤电动-微生物修复的过程。深入研究有机污染土壤电动-微生物修复过程中的影响因素和优化措施,有望为电动-微生物修复技术在有机污染土壤的场地修复及过程调控中的应用提供一定的理论依据。

Bioremediation is considered as one of the wide developing prospect methods for the clean-up of organic contaminated soil on account of it being both cost-effective and environmentally friendly.However,some hydrophobic organic pollutants,combined with their low bioavailability,make it recalcitrant to microbial degradation alone.The hybrid technology of electro-bioremediation,which couples bioremediation to electrokinetics,shows great potential in the removal of refractory organic pollutants.By the application of an electric field,the allogenic substances,nutrients and microorganisms can be dispersed into soil matrix;or the bioavailability of some refractory organics can be enhanced due to the increased mass transfer between organic pollutants and degradation bacteria;also,electrochemically induced reactions within the soil matrix can result in the destruction of the pollutants.The present paper summarized the influencing factors and the optimization measures in the electro-bioremediation process of organic contaminated soil.The main factors influencing the efficiency of the electro-bioremediation are electric intensity,bioavailability of contaminants,the types of molecular hydrocarbon structures and properties,microbial species,and environmental conditions,such as soil pH,soil type,nutrient substance and moisture contents,etc.Therefore,an appropriate electric current or voltage gradient should be selected according to the electrochemical properties of the contaminated site in the implementation of the remediation process.Besides,electro-bioremediation process of organic contaminated soil could be optimized by means of the application of surfactant/cosolvent/chelating agent,the construction of microbial communities,and the optimization of soil environmental conditions,such as the adjustment of soil pH,and the supplying of nutrients,electron acceptors or metabolic substrates.By in-depth study of the influencing factors and optimization measures in the electro-bioremediation process of organic contaminated soil,a theoretical base is expected to be provided for the application of electric-bioremediation technology to the site remediation of organic contaminated soil.