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

The paper summarises recent progress in a long-term programme of resea rch on an integrated approach to the management and real-time control of water quality in river basins. The focus of this programme is the d evelopment and application of simulation models for the dynamic behavi our of wastewater treatment plants and in-stream water quality. The mo del for the latter is based on a multiple continuously stirred tank re actor (MCSTR) approximation of fluid and solute propagation along a ri ver 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 signific ant changes to the hydraulic basis of the model (relative to earlier a pplications). They also provide a good test of the model's capabilitie s in respect of solute transport and the biochemical interactions amon g the five state variables of water quality, i.e., biochemical oxygen demand, dissolved oxygen, ammonium-N, nitrate-N, and chlorophyll-a. Th e model is applied to the assessment of management and real-time contr ol strategies for attenuating the adverse effects on stream water qual ity of storm sewage surges passing from the sewer network and through the wastewater plant. The assessment includes the coordinated manipula tion of in-stream hydraulic structures to improve controlled performan ce.