METHOD FOR PROCESSING OF SOLID HOUSEHOLD WASTES INTO ORGANIC FERTILIZERS Russian patent published in 1995 - IPC

FIELD: processing of wastes. SUBSTANCE: method for processing of solid household wastes into organic fertilizers provides for preparation and sorting of solid household wastes with separation of noncomposted fractions, and biological decomposition of remaining fraction to obtain compost. Novelty consists in additional cleaning of compost from ions of heavy and nonferrous metals by multiple circulation of aqueous phase successively through compost and cation-exchange sorbent. Besides, cleaned compost may be in further process subjected to enriching with nutrition elements for plants and/or drying and granulation. Cation-exchange sorbent is, preferably, used in H⁺ form, and cleaning process is carried on up to equalizing pH values of filtrates after composts and cation-exchange sorbent. Spent sorbent is offered to be regenerated by washing with aqueous solution of oxalic acid, and spent aqueous phase is to be returned for processing next lot of solid household wastes. Desorbate obtained after sorbent regeneration is concentrated and used as secondary raw materials in nonferrous metallurgy. EFFECT: reduced content of heavy and nonferrous metals in fertilizers and additional production of heavy and nonferrous metal concentrate as semifinished product for nonferrous metallurgy. 9 cl