Abstract: A process for removing toxic or hazardous substances from soils, sludges, sediments, clays, aqueous streams, and other non-hazardous materials comprises collecting the contaminated material, converting it to a slurry, adding one or more surfactants and/or alkaline agents to the slurry to free the toxic or hazardous substance(s) from the contaminated material and place it in the liquid phase of the slurry. Preferably, a modifier is added to the slurry in order to aid the concentration of the toxic substance in the liquid phase of the slurry. The concentrated toxic substance is then collected for disposal. Most preferably the concentration of the toxic substance is carried out in a froth flotation cell.