Abstract: A method is provided for the treatment of a waste water stream characterized by having toxic and corrosive properties due to the presence of a cyanides formates and a halide of a metal or ammonia comprising adding a ferrous ion to said waste water to convert the cyanides to iron cyanides, adding a base to said waste water until the pH of said waste water is adjusted to the range from about 9 to 11 to precipitate a sludge containing said iron cyanides, feeding said waste water to a biological reactor to convert said formates to carbon dioxide and a biological residue and recovering an environmentally upgraded waste water stream from said biological reactor.

Abstract: A process for removal of fluoride compounds from spent alkylation catalyst containing fluorosulfonic acid and sulfuric acid wherein said spent catalyst is hydrolyzed in the presence of water, at subatmospheric pressure in a vacuum digestion zone for conversion of a major portion of fluorosulfonic acid to hydrogen fluoride, wherein said hydrogen fluoride is removed from the vacuum digestion zone as a vapor, and wherein the remaining sulfuric acid rich liquid fraction of the spent catalyst is treated with silica-alumina cracking catalyst for removal of most of the remaining residual fluoride compounds for providing a sulfuric acid effluent substantially free of fluoride compounds. The hydrogen fluoride recovered is reacted with sulfur trioxide to form fresh fluorosulfonic acid which is combined with sulfuric acid to provide fresh alkylation catalyst.