CONTROLLING METHOD FOR SEWAGE TREATING PROCESS

PURPOSE:To properly set the operating conditions even when the rate of inflow water and water quality are fluctuated by automatically measuring the pH of treated water and calculating the moving average for 3-5 days and increasing or decreasing the number of revolutions of an equipment in accordance with the deviation from the set pH and allowing the pH of treated water to coincide with the set pH. CONSTITUTION:The pH of treated water 11 is compared with the set pH (about 7 pH). When the pH (moving average value) of treated water is smaller than the set pH, number of revolutions of a first and second aeration rotors 5, 6 is decreased and denitrification is advanced and the pH is raised. When the pH (moving average value) of treated water is larger than the set pH, the number of revolutions is increased and nitrification is advanced and pH is decreased. Thereby the pH of treated water 11 can be maintained close to the set pH. Since the pH of treated water 11 is affected by daily water quantity and weather, the moving average for 3-5 days is adopted as the value for control. In such a way, the pH of treated water is maintained close to 7 and excellent water quantity for treated water can be obtained. Moreover the need for high-degree expertise for operation of a process is eliminated.