METHOD OF TREATING WASTE WATERS TO REMOVE CADMIUM-CONTAINING HARMFUL IMPURITIES Russian patent published in 2003 - IPC

FIELD: waste water treatment. SUBSTANCE: multicomponent waste waters are subjected to sorption-mediated treatment to remove harmful impurities, such as cadmium, nickel, petroleum derivatives, anionic surfactants in dissolved and dispersed forms, in presence of ethylene glycol, polyvinyl alcohol, and mineral salts for use in mechanical engineering and chemical industry, in particular when manufacturing chemical power sources. Preliminarily, waste water is cleaned by two-step flocculation by adding 0.5- 2.2% (of the weight of solids) of cationic polyelectrolyte and removing in series suspended impurities (first step) and dissolved impurities. Subsequent sorption involves such sorbents as successively disposed thermally modified dolomite and activated carbon. Cationic polyelectrolyte, in particular, is copolymer of dimethylaminoethyl methacrylate dimethyl sulfate salt and acrylamide containing at least 80 mol % cationic groups, each concentration in the first state being 0.8- 2.2% and, in the second step, 0.5-1.5% based on the weight of solids. Sorption operation is accomplished by passing waste water through sorbents at velocity 0.5 to 1 cu.dm/min, volume ratio of thermomodified dolomite to activated carbon being 4:1. EFFECT: improved cleaning quality and therefore created closed water supply circuit. 3 cl, 1 dwg, 1 tbl