Brisbane Water Enviro Alliance (Sandgate, Oxley Creek and Wacol WWTP)

Bonacci Infrastructure delivered the complete structural design for the Brisbane Water Enviro Alliance (BWEA) project, which involved major infrastructure upgrades to the Sandgate, Oxley Creek and Wacol Wastewater Treatment Plants (WWTP) across Brisbane, Queensland.

Some of the largest liquid retaining structures in Australia were designed and constructed as part of the project, including the 300 x 50 metre oxidation ditch at the Oxley Creek WWTP and two 84 m diameter SCOOTA (Sandgate Circular Outside Oxidation Tank Arrangement) tanks at the Sandgate WWTP. The innovative SCOOTA tank design housed a bioreactor in the outer ring and a clarifier in the centre circle to afford a compact treatment works arrangement.

The project was delivered to Brisbane Water as a “Pure Alliance” and had a contract value of approximately $208 million. In excess of 25,000 cubic metres of structural concrete formed part of the works.

Structural works designed by Bonacci Infrastructure as part of the BWEA project included:

• Combined bioreactor / clarifier (SCOOTA) tanks
• Oxidation ditch
• Anaerobic tank
• Inlet works structures
• Flow splitter structures
• Final settling tanks
• Energex high voltage substations and switchrooms
• Control buildings
• Polymer dosing buildings and odour control slabs
• Blower, sludge and sampling buildings
• UV disinfection facilities
• Miscellaneous smaller works