Model-based evaluation of control strategies for phosphorus removal in a full-scale advanced phase isolation ditch process

摘要

A model-based evaluation of operation conditions and control strategies was conducted fornphosphorus removal in a full-scale Advanced Phase Isolation Ditch (APID) process. The APIDnprocess is an alternating type and does not have a separated anaerobic reactor. We suggestednthat it would be a suitable operational option for robust phosphorus removal by having a differenninput point for the influent and return sludge flow at specific modes. For evaluation of controlnstrategies, three cases of influent disturbance were assumed, and five manipulated variablesnwere selected for controlling the cases of disturbance. In the case of an increased influent flownrate, a combination of four manipulated variables is proposed through our simulation results asnthe best control strategy. The optimal kLa value was found to be 250/d when pollutants loadingnkept increasing without variations in the flow rate. When both the pollutants loading and theninfluent flow rates were increased simultaneously, the robust control strategy is to combine thenreturn sludge inflow point, the exclusive operation modes which have a relatively long hydraulicnretention time (HRT), operation period of 30minutes, and the increase of the return sludge flownrate in proportion to the influent flow rate added to 300/d of k a value.