This paper presents the modification and the application of the conceptual wash-off model initially proposed by the SWMM on five separate urban catchments with very different characteristics and during a lot of rainfall events. To allow measurements on real sites to be considered, this model was incorporated in an overall model including simulation build-up, sediment transport in collector as well as runoff and hydraulics. This modified model has been calibrated, validated, transposed and completed with sensitivity analysis of parameters and initial conditions. The proposed model gives some improvement to the results of the initial model: an adaptation to a large range of rainfalls, the correct reproduction of the peak values and satisfying reproduction of the beginning and the end of the TSS pollutograph.

Better controlling and optimising the plant's processes has become a priority for WWTP (Wastewater Treatment Plant) managers. The main objective of this project is to develop a simplified mathematical tool able to reproduce and anticipate the behaviour of the Tougas WWTP (Nantes, France). This tool is aimed to be used directly by the managers of the site. The mathematical WWTP model was created using the software WEST. This paper describes the studied site and the modelling results obtained during the stage of the model calibration and validation. The good simulation results have allowed to show that despite a first very simple description of the WWTP, the model was able to correctly predict the nitrogen composition (ammonia and nitrate) of the effluent and the daily sludge extraction. Then, a second more detailed configuration of the WWTP was implemented. It has allowed to independently study the behaviour of each of four biological trains. Once this first stage will be completely achieved, the remainder of the study will focus on the operational use of a simplified simulator with the purpose of optimising the Tougas WWTP operation.

This paper presents results of long term pollution simulations on the example of the sewerage system of Grand-Couronne. This modelling work is part of a study where objective is to develop a method to define the reference flow of a WWTP. The model HYDROWORKS DM has been successfully validated in hydraulics and pollution for the sewer network, for long time simulations. A conceptual model has been built to model the pollution in the tank at the outlet of the combined system. One synthetic year of rain has been used to simulate the working of the "up stream system" of the WWTP (combined sewer + tank + separate sewer + pre-treatments) and has been successfully validated by measurements of the 1998-1999 year. If this paper is focused on the "up stream system", the SIMBA/SIMBAD WWTP model has been successfully calibrated and validated too, and the combination represents a fully validated "Integrated Model" for the sewerage system.

This paper presents the application of the conceptual total load model of Velikanov through a description of the solids behaviour, its calibration using numerical optimisation and the results on real sites. In order to take into account the full scale measurements, the Velikanov's model has been included in a global model for solid production and transport in sewer system which is divided into four modules: hydrologic, hydraulic (Muskingum model), pollution (build-up, wash off and total load) and calibration functions. The calibration of Velikanov parameters has been made using a procedure of numerical optimisation based on the Powell method. The solids behaviour is characterised by settling velocity (ωs) and density (s) which varies between fine particles (ωs=5.4m/h and s=2.00) essentially transported in suspension and coarse particles (ωs=45m/h and s=2.65). The results of the calibration phase on three real French sites which presented dry weather sediments and the validation phase can be considered of good quality. Simultaneous measurements of rainfall, hydraulic and TSS concentration allowed a large range of calibration and validation. This model provides a satisfying fitting of the real TSS pollutographs and this, considering the global form, maximal value and the temporal position.