| 摘要 |
<p>PURPOSE:To accurately grasp the total amount of sludge in the process of purifying sewage, by providing a circuit which calculates the total amount of sludge in the system from the amount of circulating sludge and the times of sludge staying in an aerating cell and the final precipitating pool. CONSTITUTION:From values measured by an MLSS meter 7 provided at the outlet of an aerating cell 1, a meter 3 for the amount of inflow sewage and a flow meter 4 for returned sludge, the amount of circulating sludge is calculated by the first arithmetic circuit 9. From values measured by the meter 3 for the amount of inflow sewage and the flow meter 4 for returned sludge, the time of sludge staying in the aerating cell 1 is calculated by the second arithmetic circuit 10. On the basis of the values measured by said meters 3, 4 and values measured by a flow meter 5 for excess sludge to be withdrawn and an SV meter 8 provided in the final precipitating pool 2, the time of sludge staying in the final precipitating pool is calculated by the third arithmetic circuit 11. On the basis of the outputs of said arithmetic circuits 9-11, the total amount of sludge is calculated by the forth arithmetic circuit 14. In addition, the fifth arithmetic circuit 13 to determine the amount of excess sludge to be withdrawn is added. According to this system, the total amount of sludge in the system can be accurately observed.</p> |
