A feed forward control method for adjusting the total sludge volume in activated sludge process

The activated sludge process is widely used in wastewater treatment. In order to get more highly purified effluent, a control method for adjusting the total volume of in-process sludge should be developed. The process has nonlinear and distributed parameter characteristics with a long time delay. A feed forward control method is proposed in this paper, assuming variations of daily influent load can be predicted. In this method, the respective flow rate of return sludge and waste sludge is determined at each control timing stage, based on the process dynamics simulators. This method is a practical approach for controlling the complex distributed parameter processes. The method is applied to Mixed Liquor Suspended Solid (MLSS) stabilization control. The results show that MLSS can be stabilized within a 5% deviation from the desired value.