Review of hydrodynamic separator-regulator efficiencies for practical application

Different approaches to assess hydrodynamic separator performance are presented. These approaches are applied to the same data, evaluated at both steady state and at unsteady state conditions. It is shown that the overflow and baseflow concentration of particles at steady state conditions is increasing with increasing hydraulic load under constant inflow concentration. The different qualitative approaches allow a very contrary interpretation. Their value increases, decreases or has a maximum over the varied flow conditions. Furthermore it is shown that none of the presented approaches can accurately describe hydrodynamic separator performance at unsteady state conditions. Finally a set of two approaches is presented which is able to describe the quantitative and qualitative performance of a hydrodynamic separator and also takes unsteady state conditions into account.