METHOD FOR CONTROLLING MOVABLE WEIR FOR EFFLUENT FROM BIOLOGICAL OXIDATION TANK IN WATER PURIFYING PLANT

摘要

PURPOSE:To maintain the quality of biologically oxidized water by controlling the position of a movable weir for the effluent, and controlling the effective depth of water. CONSTITUTION:The biological membrane contact time is obtained by a biological membrane contact time arithmetic circuit 7-1 from the temp. measured by a thermometer 3. The effective depth of water required for the contact time obtained by the arithmetic circuit 7-1 is then calculated by an effective depth arithmetic circuit 7-2. The height of the movable weir for the effluent is adjusted by a movable weir control circuit 7-3 so that the depth is controlled to the calculated value. By this method, stabilized-quality treated water can be obtained irrespective of the variations in the quality of raw water, the depth of water in a biological oxidation vessel 1 can be controlled to a necessary minimum, and hence the operation power cost of a blower can be reduced.