Investigations into and optimisation of the performance of sewage detention tanks during storm rainfall events

Combined Sewage Detention Tanks (CSDT) are components of combined sewage sy stems commonly used in Germany. A lack of knowledge of the processes occurr ing within these structures causes the engineer to apply conceptual approac hes in the simulation of pollutant transport. The investigations presented were implemented in an integrated systematic way. Extensive analytical, exp erimental and numerical studies of steady and transient phenomena taking pl ace in CSDTs were carried out simulating different levels of hydraulic load . The study of the flow field and the simulation of sedimentation and erosi on under realistic conditions resulted in proposals for modification and op timisation of the function of CSDTs. A simple way of predicting the cleanin g efficiency is presented. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.