• Asia Pacific Rentals & Services
  • 08/09/2025

INCREASING CAPACITY AT COOMBABAH SEWAGE TREATMENT PLANT

Westwater (a Centurion company) upgraded the sodium hypochlorite dosing and storage system at Coombabah, the Gold Coast’s largest sewage treatment plant, to handle growing demand. The new high-capacity, automated system strengthens disinfection, improves efficiency, and ensures reliable treatment for a population of more than 300,000.


The Client

The Coombabah Sewage Treatment Plant (STP) is the largest sewage treatment facility within the Gold Coast City Council, servicing an estimated population of around 330,000, approximately half of the City’s sewage.

Client Challenges

An assessment of the sewage treatment plant catchment area found the existing facility would be at or near capacity by the end of 2021. The client needed to:

  • Safely store up to 25,000L of sodium hypochlorite on site
  • Deliver the ability to dose into a new chlorine contact tank at a quantified 1,100L/hr using a duty/assist dosing system
  • Strengthen bacterial disinfection and auxiliary treatment processes to ensure reliable sewage treatment for a growing population.

Our Solutions

WestWater (a Centurion company) upgraded the Sodium Hypochlorite Dosing and Storage Facility at Coombabah STP as part of the client’s Stage 6 capital works program.

The system delivered:

  • Three 375L/hr digital dosing pumps in Duty/Duty/Assist configuration
  • Chemical supply via two 12.5KL sodium hypochlorite day storage tanks
  • Profibus-connected automation, enabling seamless duty switching and flow verification through magnetic flow meters
  • Automated level monitoring and refilling from the site’s bulk storage when required
  • Automated outlet valves on day tanks to allow flexible duty selection.

Results

  • A high-capacity, automated chlorine dosing system capable of reliably meeting demand at 1,100L/hr
  • Improved efficiency and reduced manual handling through automated refilling and tank monitoring
  • Greater flexibility and reliability with Duty/Duty/Assist dosing formation
  • Enhanced bacterial disinfection performance as part of the overall sewage treatment process.

Conclusion

The Coombabah sewage treatment plant upgrade highlights Westwater's (a Centurion company) ability to deliver large-scale, automated chemical dosing solutions for critical municipal infrastructure. By combining robust engineering, automation, and compliance, we strengthened the region’s sewage treatment capacity and ensured safe, efficient operations for one of Queensland’s largest facilities.

Contact Information

For more information, contact the team at E: sales@westwater.com.au, T: +61 8 9248 2411 (Perth, Western Australia), T: +61 7 3806 2900 (Brisbane, Queensland)

Have a look at our other case studies.