Use of real time control modelling on the urban sewage system of Nancy

Since 1991, European Legislation on the urban treatment of wastewater requi res local authorities to take into account the treatment of polluted water transported by the sewerage system and this during dry and wet weather cond itions. In the seventies, the urban Community of Grand Nancy constructed st orage tanks in its sewerage system in order to prevent flooding and wish to day to use them to reduce and control the pollution discharges into the rec eiving water. This action is a part of a European LIFE project 1996-2000. T he main aim of this project was to assess the effectiveness of reducing pol lution of one particular retention basin, the 12,000 m(3) Gentilly tank. Th is one has two operating modes: protection against floods during heavy rain and reduction of pollutant overflows during lighter rain. To assess its ef fect on the pollutant discharge, the HYDROWORKS DM (TM) Software and its Re al Time Control Module have been used, calibrated and validated. As this st udy is still in progress, this paper describes the studied site and the mod elling results under different weather conditions and shows that the mathem atical model can be used to simulate the operation of the catchment area an d its associated sewerage system realistically.