Abstract: Oil which is highly contaminated with water and particulate solids is purified by serial settling and recirculation steps, so that the amount of highly emulsified oil-water mixtures and highly dispersed solid mixtures is substantially reduced.

Abstract: An improved landfarming medium and process is disclosed in which hydrocarbon wastes are disposed of by dispersing them in a medium composed of a mixture of soil containing hydrocarbon-oxidizing microorganisms and a spent, solid, particulate, porous hydrocarbon cracking catalyst and/or a spent, solid, particulate, porous filtration medium.

Abstract: A feed-effluent heat exchanger in a sour water stripping system having sour water stripping means, sour water storage means, and a stripper feed-effluent heat exchanger, is cleaned when the stripped water pathway in the heat exchanger becomes fouled, by passing sour water having a pH of greater than 8 from the storage means through the stripped water pathway in the exchanger at a temperature of at least 70.degree. F., and returning the sour water to the sour water storage means.

Abstract: A method is described for cleaning nonsettling oil-solid mixtures from the bottom of catalytic cracking rundown tanks wherein a solvent of particular specifications is introduced in the rundown tank and circulated around, in and through the non-settling oil solids with an angularly adjustable pump. After the floating oil-solid mixture has been separated by the solvent, the solvent and liquid are removed from the tank, separated and recycled to process streams. The remaining settled solid sediments may then be washed with an aqueous solution circulated in the tank with the adjustable pump to water-wash additional oils from the solid sediments, and the aqueous solution and oils carried therewith are removed from the tank and separated. The remaining solid materials are then vacuumed from the tank or water-washed from the tank to complete the cleaning process initiated totally from outside of the tank.