| 摘要 |
<p>PURPOSE:To perform a predictive control of MLSS concentration exactly with an allowance for growth amount by controlling the amount of sludge inside aeration tank by making a predictive calculation of concentration of mixed liquor suspended solids (MLSS) in aeration tank. CONSTITUTION:Using the actually measured values of entering sewage amount, entering sewage SS concentration, MLSS concentration at the outlet of aeration tank, returned sludge amount, and returned sludge concentration, the amount of grown sludge and the growth rate are obtained from an equation of sludge balance at the inlet and outlet of the aeration tank with an allowance for the residence time. Then, the MLSS concentration at the outlet of the aeration tank is claculated from values obtained by predicting the growth rate on that day on the basis of the growth rates in the past, and then the residence time is calculated by using the predicted value of inflow and the amount of returned sludge in the following scheduled operations. Also, after the calculation of predicted MLSS concentration after the residence time at the outlet of the aeration tank for entering sewage at the present time, it is compared with the set value of MLSS received separately, and if the set value is unsatisfying, recalculation is made by changing returned sludge amount and the returned sludge amount is determined by aiming at the MLSS concentration as a target.</p> |
