Soil and Water Decontamination by Extraction With Surfactants

Samples of soil from contaminated sites and industrial sludges and residues were treated in the laboratory by extraction with water solutions containing surfactants and other additives. The contaminants included coal tar, PCBs, hydrocarbons, chlorinated hydrocarbons, nitrotoluenes, and heavy metals. Some of the samples contained highly complex mixtures of organic and heavy metal contaminants. Reduction of the contaminant levels to < 1 ppm was typically attained by the extraction treatment. The contaminant-laden wash liquors were purified by ultra-filtration, followed by air flotation. The cost of treatment by a commercial-scale, integrated process, consisting of the extraction and was liquor purification steps, was estimated to be in the range of $50.00-80.00/ton of treated soil, depending on soil matrix properties, chemical composition of the contaminants, and other site-specific factors.