Vortex separators as new devices for combined sewer overflows (CSOs) claim good efficiencies which can be confirmed by laboratory tests. Such model tests are usually performed in reduced scale and under steady-flow conditions. This paper describes a possible way to transfer model test results to the prototype scale. As a first step, the most essential parameters must be accounted for using a proper dimensional analysis which also considers scale effects. It will result in dimensionless efficiency curves which allow prediction of prototype efficiencies, yet valid for steady flow only. To take into account the variability of annual inflow as well as dynamic effects like filling and emptying of a particular separator, the efficiency characteristics of the separator are combined with a quantity-quality simulation model. Such a numerical model is able to compute inflow and outflow hydrographs and pollutographs and to account for the catchment data at the given site. It allows the computation of annual pollutant loads as well as of the percentage of sewage sediment fed to the treatment plant, i.e. an annual separation efficiency.

This content is only available as a PDF.