NONLINEAR AND SET-POINT CONTROL OF THE DISSOLVED-OXYGEN CONCENTRATIONIN AN ACTIVATED-SLUDGE PROCESS

Control of the dissolved oxygen concentration (DO) in an activated slu dge process is of considerable importance because of economy and proce ss efficiency. A strategy for designing a nonlinear DO controller was developed. The basic idea was to take the nonlinear oxygen transfer fu nction into account in the controller design. Simulations illustrated that a nonlinear DO controller outperforms a standard PI controller. T his was also cofirmed in a pilot-scale plant experiment, ii supervisio n (set-point) controller for the DO is also outlined. Initial simulati ons showed promising results where the aeration system is used more ef ficiently and the effluent ammonia concentration could be maintained l ow. Copyright (C) 1996 IAWQ. Published by Elsevier Science Ltd.