Brief description of the biological purification of residual water and installation for implementing it.

摘要

1496069 Biological treatment of effluents J R KAELIN 20 Jan 1975 [18 Nov 1974] 2301/75 Heading C1C A method for the biological purification of effluent, comprising the steps of (i) feeding effluent to be purified successively to first and second tanks, acting as activation tanks, in a set of at least three interconnected tanks; introducing oxygen or an oxygen-containing mixture into the effluent in said first and second tanks; (ii) feeding, after a predetermined average residence time in said first and second tanks, the effluent from the second tank to a third tank of the set, said third tank being a settling tank; (iii) withdrawing clarified effluent from the third tank, steps (i), (ii) and (iii) being continued until the concentration of activated sludge in the first tank is reduced to below a predetermined value; then reversing the flow of effluent through the set of tanks; and operating the third and second tanks as activation tanks and the first tank as a settling tank and apparatus for carrying out the process is described.