Efficiency of a continuous deflective separation (CDS) unit in removing contaminants from urban stormwater

Abstract

The weighted average concentration (WAC) of total suspended solids (TSS) in stormwater effluent from a continuous deflective separation (CDS) unit in Port Jackson (Australia) catchment was reduced by an average 28% during six high-flow events, but some TSS was released during turbulent, high-flow events. The average removal efficiency of metals Cr, Cu, Pb Mn, Ni, Zn and Fe varied considerably (−49% for Pb and +10% for Mn), whereas Ni and Zn were inefficiently removed by the device. Average concentrations of TKN, NO_x and TP were similar at both in- and out-flow points and faecal coliforms counts were slightly reduced.

Keywords:

• urban water
• urban water management
• continuous deflective separation (CDS)
• stormwater
• heavy metals
• nutrients

Acknowledgements

The project was funded by Drummoyne Council, the New South Wales Environment Protection Authority (NSW EPA) and the Stormwater Trust. Staff from these organisations who assisted the project are gratefully acknowledged. The useful comments by the two anonymous reviewers are greatly appreciated.