One of the main restricting factors in the remediation of soils is the low aqueous solubility of several organic compounds, which leads to resistance to mobilization by conventional pump and treat measures and to low bioavailability. The application of surfactants to resolve these problems has been a focus of research in recent years. However, usefulness of surfactant addition has been conversely discussed in literature. Promising results obtained with model contaminations in the laboratory often failed under real world conditions.
Surface-active additives have the potential to improve the efficiency of soil clean-up by physico-chemical and biological processes if their functional properties are adjusted to the special demands of the remediation technology and the soil/contaminant system. However, how to find tailor-made solutions by applying the different utilizable wetting, dispersing, emulsifying and solubilizing properties, is not understood properly so far.
The paper gives an overview of results obtained in recent years working on selection of surface-active additive combinations for different purposes. This included surfactant combinations for the hydraulic in-situ remediation of soils, for the stimulation of biodegradation, several surfactant formulations with high extraction efficiency for different contaminants, special additives for the enhanced washing of tar contaminated soils as well as the development of a two-step bioreactor process for removal of contaminants with low bioavailability. The article is intended to provide a basis for discussion of problems associated with surfactant application and possibly for future cooperation.
(Originally presented at the FZK/TNO International Conference on Contaminated Land - "Contaminated Soil '2000", 18 - 22 September 2000, Leipzig)
The author welcomes related discussions and comments and is very interested in providing confidential information for research or commercialisation purposes.
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