Optimization of the Operation of the Oxidation Ditch Process Incorporating a Dynamic Model

A procedure for the optimal management of the oxidation ditch process was developed, comprising the integration of a dynamic process model, an input forecaster and an optimization algorithm. The system can be set to optimize operating costs (having the effluent quality as constraint) or process performance (having a maximum budget as constraint). Simulations with data from full scale oxidation ditches showed the usefulness of the method in terms of on-line control and/or off-line planning. A comparison between the proposed strategy and other conventional control policies was done by Monte Carlo simulation, varying the values of the inputs and initial states. Statistical analysis of the results indicated that, in general, the optimal management was able to give a significantly better effluent quality but, in some cases, at higher operating costs.