SEWAGE TREATMENT METHOD Russian patent published in 2000 - IPC

FIELD: treatment of industrial sewage including non-ferrous metallurgy, mining and chemical industries and all enterprises where flotation is required. SUBSTANCE: proposed method includes three-stages: first stage includes preparation of gas-and- liquid mixture on base of surface-active agents of heteropolar composition which interact with surface of gas bubbles reducing their surface energy; second and third stages include flotation from volume and foam separation which take place simultaneously in uptake flows of activated gas-and-liquid mixture for removal of unwanted admixtures from sewage. Activated gas-and-liquid mixture is held till limiting adsorption is obtained at gas-liquid interface, after which water is additionally introduced at ratio of starting solution of surface -active agent of 3 to 11:1. Surface-active agent is used at concentration not below critical concentration of micelle forming. EFFECT: intensification of cleaning process; reduced flotation time. 2 cl, 1 ex