Abstract: A chemical process for treating pit waste contaminated with chromated copper arsenate (i.e. CCA). CCA is recovered for recycling, and remaining solids are decontaminated for safe disposal. Pit wastes are pulverized and reacted with concentrate sulfuric or phosphoric acid. Wood particles are partially decomposed and approximately 60% to 70% of the CCA is leached out. The acid-treated mixture is centrifuged or filtered to separate liquids from solids. Liquids are recycled for reuse in the CCA process. CCA-bearing solids enter a heated digester equipped with an air or water cooled condenser. Concentrated nitric and sulfuric acids are inputted into the digester and the ratio of nitric acid to sulfuric acid to solids is approximately six to two to one by volume. Nitric acid completely oxidizes all organic matter in the solids. Sulfuric acid serves as a dehydrating agent and liquid media for CCA. The initial oxidation is carried out at a temperature greater than 70.degree. C. and less than 100.degree. C.

Abstract: A method and apparatus for the removal and safe disposal of trace quantities of toxic or carcinogenic hydrocarbon compounds from waste water. As a result of this process, such hydrocarbon compounds are converted to less noxious, readily disposable compounds. The waste water is first admixed with rehydratable alumina to equilibrium, whereby hydrocarbon pollutant compounds are absorbed onto the surface of the rehydratable alumina. The compounds are then removed from the waste water by filtration, and the remaining water is safely drained off. The remaining rehydratable alumina containing the toxic compounds is then reactivated by heating for reuse in subsequent processing. Non-reusable alumina is digested in sulfuric acid to decompose any remaining toxic hydrocarbon comppounds to less noxious compounds and to convert the alumina to water-soluble and conveniently disposable aluminum sulfate.