OPTIMAL-CONTROL OF THE ACTIVATED-SLUDGE PROCESS - EFFECT OF SLUDGE STORAGE

This paper describes an application of an optimal control method in the regulation of the activated sludge process including a biological reactor, a variable volume sludge storage tank and a settler. The control variables represent flowrates (1) from the settler to the storage tank, (2) from the storage tank to the biological reactor and (3) from the storage tank to wastage. The control problem is to determine optimal control variable sequences that minimize effluent organics variability on a daily horizon. The results indicate that the presence of the storage tank significantly improves process regulation with the relative control efficiency reduced with increasing storage capacity. The researched methodology lends itself to on-line process control implementation.