Advances in Modelling Particle Transport in Urban Storm- and Wastewater Systems

Abstract

Suspended solids in sewers not only carry organic and inorganic pollution but are also the preferred vector for heavy metals, hydrocarbons, many hydrophobic micropollutants and pathogens that are preferentially attached to them. Their behaviour in sewer systems has thus been object of many studies, but, unfortunately the predictive power of the available models remains limited due to the complexity of the processes that determine their transport, sampling and measurement. This contribution summarizes 10 years of research at Université Laval that took advantage of the ViCAs measurement set-up that allows for characterizing the wastewater particles’ settling velocity distribution (PSVD) to come up with a conceptual modelling framework of storm and wastewater transport systems in which mass balances are made of particle classes, each with a characteristic settling velocity. The models have been calibrated and validated for stormwater basins, combined sewer retention tanks, primary clarifiers and complete combined sewer systems, from sewer catchment to stormwater basins outlets, sewer overflows and primary clarifier effluents. The ViCAs experimental set-up is simple to build and work with, and has intrinsic quality control indicators that allow evaluating the quality of the obtained PSVD’s.