10.4122/1.1000001119 Salvia-Castellvi, M. Iffly, J. F. Guignard, C. Pfister, L. Characterisation of urban stormwater runoff from separated sewer overflows in Luxembourg DTU Library, Technical University of Denmark (DTU) 2005 Urban drainage stormwater separated sewer overflows pollutant EMC pollutant load CREBS, CRP-Gabriel Lippmann en Conference presentation 10.4122/1.1000001120 text/xml 1 Separated sewer overflows (SSOs) are well known for their overflows of untreated water during storm events. In this study, a total of 22 storms was surveyed in two separated sewer systems in the town of Luxembourg during the period from August 2003 to February 2004. For each storm event, both runoff and quality parameters were analysed. Inter-storm and intra-storm variability were determined for both sewers, and the relationships between Event Mean Concentrations (EMC) and runoff patterns analysed. The magnitude of the first flush effect was calculated through the dimensionless curves representing the variation of the cumulative pollutant mass ratio in relation to the cumulative volume ratio. The presence of illicit sanitary inputs in one of the sewers produces a significant first flush effect in its storm runoff as well as higher EMC for all the pollutants related to suspended solids.