Method and process for rendering waste substances harmless

Abstract

A method is provided for the treatment of hydrocarbon-contaminated soil by chemical hydrolysis and/or oxidation of said hydrocarbons on the hydrocarbon-contaminated soil. The method includes conditioning lime with a particularly defined fatty-acid activator. The so-conditioned lime is blended with physically-preconditioned, moist, hydrocarbon-contaminated soil, the degree of dispersion being at least near microscopic level. A charge of the such blended lime/soil is conveyed to an enclosed reaction vessel, where hydration of the lime is carried out. The heat of the hydration reaction is retained within the vessel, so that hydrolysis of the fatty acid conditioner and/or hydrocarbon contaminants in the soil is effected. Air or oxygen-enriched air is substantially-simultaneously introduced into the reaction vessel together with steam and/or water as required by the chemical reactions, thereby to effect a flameless, intermediate-temperature oxidation of the hydrocarbons or their hydrolyzed degradation products. Such decontaminated soil product is discharged from the reaction vessel by passing the soil product, in dry, dusty hydrophobic form through a treating zone where it is sprayed with a surfactant. The surfactant-treated decontaminated soil product is passed to a blender where it is mixed with sufficient water to provide a substantially dust-free product.