10.4122/1.1000001735 Welker, A. Fate and behaviour of selected organic substances in the urban drainage system DTU Library, Technical University of Denmark (DTU) 2005 combined sewer system CSO pollution load simulation organic substances University of Kaiserslautern, Institute of Environmental Engineering en Conference presentation 10.4122/1.1000001736 text/xml 1 For the presented study a set of \342\200\236new\342\200\234 substances was selected to analyze their origin and be-havior in urban water systems. The consequences of different strategies for emission control in combined sewer systems are discussed by the example of these substances. At first results of a literature survey on the occurrence of the selected substances in the main flow types of urban drainage systems are presented. The results of measurement programs show a wide range of concentrations for various substances. Main reasons for this divergence are different conditions of field studies in terms of investigation methodologies, site specific factors and hydrological conditions. Followed by a summary representative concentrations in dry weather flow, surface runoff and WWTP effluent pollution load were stated. Simulations for a fictive catchment (combined sewer system) were conducted. Three scenarios were de-signed, that represent commonly used measures for emission control. For these scenarios an-nual pollution loads from CSO structures and WWTP were calculated. The results are predominately dependent on substance properties like origin (dry weather flow versus surface runoff) and the elimination rate in the WWTP. In summary the results give in-dications about possible strategies to reduce pollutant emissions from combined sewer sys-tems. These are not only depending on the catchment conditions but also extremely differ with the considered substance.