Abstract: A method and apparatus is disclosed for treating and processing an oil, water or oil and water-contaminated substrate such as oil field waste. The substrate may be pretreated with water and/or surfactant and may be mixed under low shear conditions with a base such as a compound containing alkaline earth or lime and an optional catalyst. Mixing the substrate with the base creates a heat. Next, the substrate may be mixed with an acid such as sulfuric acid. As the substrate is mixed, it causes an exothermic reaction with a heat that vaporizes the oil, reaction products and water. Recoverable constituents in the vapor can be condensed in a vapor collection system. The treated substrate may be essentially free of oil and has a controlled water content and pH that can be adjusted according to the use of the end dry product.