Grey Box Modelling of First Flush and Incoming Wastewater at a Wastewater Treatment Plant

On-line measurements of turbidity, UV absorption and flow in the inlet to a Danish wastewater treatment plant are used to establish a dynamic model of the deposition of pollutants in the sewer system and the pollutant mass flow to the treatment plant. The modelling is made using the grey box approach, which is a statistical method that uses known physical relations to formulate the model. The dynamics of the sewer are modelled by means of continuous time stochastic differential equations combined with dry weather diurnal pollutant mass flows.