South Caboolture Recycled Water Disinfection Facility

QLD
Unitywater
In progress

Abergeldie is delivering the Caboolture South Recycled Water Facility for Unitywater. The project involves a conversion/recommissioning of the South Caboolture Water Reclamation Plant (WRP). The works are critical for Unitywater's Wamuran Irrigation Scheme which will deliver 2.6 gigalitres of Class A recycled water each year to farms in Wamuran for irrigation, providing year-round, reliable water supplier for growers and reducing the nutrient discharge into the Caboolture River.

Scope of Works

The works include: 

  • New wet weather bypass for the STP 750mm GRP pipe including areas of deep excavation (5m) and high water table.
  • Reconfiguration of existing balance tank using adjustable penstocks to allow for better split to bioreactors.
  • Decommissioning and disposal of redundant infrastructure at both STP and RTP sites.
  • New STP feed pump station and reconfiguration to allow transfer of chlorinated effluent from the STP to the RTP.
  • Conversion of existing biological activated carbon filters to media filters.
  • Conversion of existing ozone treatment tanks to Chlorine contact tanks.
  • New UV Feed pump station and UV disinfection.
  • New Chlorine gas dosing disinfection facility.
  • Refurbishment and minor modifications to the Recycled water storage Reservoir.
  • New switch rooms and control system for the new RTP.
  • Proof of performance and commissioning prior to handover. 

Innovative methodologies to de-risk construction

The Caboolture South Recycled Water Disinfection Facility Project is highly complex and includes civil, mechanical, structural, electrical and control works. The works are spread across both the Recycled Water Treatment Plant and the Sewage Treatment Plant at the Caboolture South Site, making logistics and coordination amongst various trades and across multiple areas integral to the project's success. The works at the STP are being carried out under brownfield conditions and it has been essential to keep the plant operational outside of planned shutdowns for cutovers.

The project involved demolishing a below-ground digester tank and constructing a new transfer pimp station in its place.  Due to a high water table and the structure's proximity to other operational structures, our team proposed and successfully implemented an alternative methodology, which was subsequently accepted. This involved piling through the base of the existing tank instead of demolishing it, enhancing safety and minimising environmental risks during construction. 

The team also proposed an alternative design for the wet weather bypass, incoporating actuated weirs to split the flows into the bioreactors. This was accepted and resulted in significant cost savings for Unitywater.


Critical works for the Wamuran Scheme

The works and the new disinfection facility are critical for the Wamuran Scheme which will deliver 2.6 gigalitres of Class A recycled water each year to farms in Wamuran for irrigation. The Wamuran Irrigation Scheme will provide reliable water supply for growers and reduce the nutrient discharge into the Caboolture River, a win for the community and the environment.