To meet the challenge of a very large storage requirement within a small footprint faced by the Gateway WA project, and many other road corridor projects like it, what is probably the largest Rocla Downstream Defender® separator system in Australia was recently installed at the corner of Leach Highway and Abernethy Road on this $1b project.
Rocla Regional Sales Manager Craig Donaldson says the system – a Rocla Downstream Defender® 3000 with grit chambers and in line storage tank – weighs about 70 tonnes in total and was dropped into position by crane at the end of April.
The role of the system is to remove accumulated oil and sediment from the stormwater discharge of a main transport corridor, as well as provide emergency, catastrophic oil spill control for a fully laden 24,000 litre petrol tanker.
Stephen D Baker, Manager Water Quality for Rocla, says the unique quality of the Rocla Downstream Defender® is that pipe geometries can allow complex inlet /outlet pipe configurations. “Alternative solutions could have involved catchment splitting over several sites, which would have meant more complex maintenance regimes, and long term costs,” he says.
Advanced separation technology
The Rocla Downstream Defender® separator is an advanced hydrodynamic vortex separator. Rotary and shear forces are generated to augment gravitational forces and remove settling solids using a much smaller area than sedimentation basins. An oil and floatables trap within the vessel provides a compact solution for non point source pollution.
With the addition of a spill tank, the Rocla Downstream Defender® separator provides an effective spill control system as well as removing sediments, fines and litter. This is an ideal solution for major road projects where there is a requirement to control potential hydrocarbon spills.