IDENTIFICATION AND APPLICATION OF A DYNAMIC-MODEL FOR OPERATIONAL MANAGEMENT OF WATER-QUALITY

The paper summarises recent progress in a long-term programme of research on an integrated approach to the management and real-time control of water quality in river basins. The focus of this programme is the development and application of simulation models for the dynamic behaviour of wastewater treatment plants and in-stream water quality. The model for the latter is based on a multiple continuously stirred tank reactor (MCSTR) approximation of fluid and solute propagation along a river system. Results are presented for the identification (calibration) of this model with reference to field observations from the River Cam in eastern England. These results illustrate the benefits of significant changes to the hydraulic basis of the model (relative to earlier applications). They also provide a good test of the model's capabilities in respect of solute transport and the biochemical interactions among the five state variables of water quality, i.e., biochemical oxygen demand, dissolved oxygen, ammonium-N, nitrate-N, and chlorophyll-a. The model is applied to the assessment of management and real-time control strategies for attenuating the adverse effects on stream water quality of storm sewage surges passing from the sewer network and through the wastewater plant. The assessment includes the coordinated manipulation of in-stream hydraulic structures to improve controlled performance.