International Evaluation of In-situ Biorestoration of Contaminated Soil andGroundwater

摘要

The philosophy of in-situ biorestoration is to stimulate the indigenous soilmicroorganisms by improving the environmental conditions in the soil using a water recirculation system. The objective of the project is to show the possibilities for application of the technique in relation with contaminants, soil conditions and other site-specific circumstances by means of integration and evaluation of results of in-situ biorestoration projects. The project is limited to the Netherlands, West Germany and the USA. It was implemented by visiting 23 relevant projects in these three countries, which play a leading role in the development of remediation techniques for contaminated soil and groundwater. The descriptions are mainly based on the literature on the project and direct information. This includes the background of the contaminated sites, preliminary site characterization, biodegradation studies, system design, analytical procedures, results and costs. In-situ biorestoration is a relatively young, developing technology. It has been used at several locations, mainly in the USA. It can be used especially for locations at which both the unsaturated zone and the groundwater are contaminated with hydrocarbons. A precondition is a good permeability of the soil. Experience has especially been gained with in-situ biorestoration at hydrocarbon-contaminated petrol stations and industrial sites. The system generally consists of a water recirculation system, above groundwater treatment and conditioning of the infiltrating water with nutrients and an oxygen source. Recommendations from the evaluation include a further stimulation of the development of this technology, improvement of the preliminary research, expansion of the applicability to more recalcitrant contaminants, research on bio-availability and research into oxygen supply and distribution in the subsoil.