GB1344904A - Effluent purification - Google Patents

Abstract

1344904 Purifying effluents NIKEX NEHEZIPARI KULKERESKEDELMI VALLALAT 15 Sept 1971 42960/71 Heading C1C A process for biologically purifying domestic or industrial effluent comprises passing the effluent through a mixing tank and one or more aerobic tanks and recirculating a portion of effluent containing dissolved oxygen produced photosynthetically from the or one of the aerobic tanks to the mixing tank. The portion to be recirculated is taken during the daily period when, and from that region of the aerobic tank(s) where the content of dissolved oxygen produced photosynthetically is at or near its maximum value. The effluent may be in the aerobic tanks for 2-40 days. The apparatus of Fig. 3 comprises mixing tank 2 provided with ventilator 3 and surrounded by rings of tanks 4a, 4b and 4c-4h. To provide recirculation from tanks 4a, 4b to tank 2 the apparatus has automatically controlled pump 6, floating pipes 11a, 11b and pipes 7a, 7b. Duct 12 and pipes 8a, 8b with valves 13a, 13b conduct effluent from tank 2 to tanks 4a, 4b. Ducts 16a, 16b and pipes 14a, 14b, 26 with valves 15a, 15b, 27 provide communication between tanks 4a, 4b and tank 4f, 4e, 4c. A floating duct, e.g. 17, 17a is provided between each two adjacent tanks 4c- 4f. The ventilator 3 may be an automatically controlled floating turbine or blower. In operation the effluent may pass through all or some of the tanks on its way to discharge 21. For example, the effluent may flow through (1) tanks 2, 4a-4h, (2) tanks 2, 4a, 4f-4h or (3) tanks 2, 4b, 4e-4c.