Wellington Sludge Minimisation Facility

Customer:  Wellington City Council

Contract: Construct 

Location:  Moa Point, Wellington

Water & Wastewater Solutions New Zealand & Pacific Islands

Fast Facts: 

  • 21m tall steel process building. 
  • 2 14m high concrete digestor tanks 
  • 48 mechanical system packages 
  • 2,100 valves 
  • 46km cabling 
  • 10km of pipeline 

The Wellington Sludge Minimisation Facility (SMF) Project aims to address the sludge produced at the current Moa Point location by creating a new facility that will reduce the amount of waste going to landfill. 

This new facility will use Thermal Hydrolysis – heating and drying under pressure - to sterilise and reduce the volume of the sludge, making it more biodegradable. Biogas will be captured and used to power the facility, substantially reducing carbon emissions.  

The sustainability benefits of the chosen design include: 

  • Reduced sludge volumes by up to 80% 
  • Reduced carbon emissions from the treatment and processing process by 60% 
  • Minimises the amount of waste going to landfill  
  • Produces a low odour stabilised (inert) product  
  • As mentioned above, offers the potential for sludge to be used productively, including as a soil conditioner, fertiliser, and fuel for industrial heat 
  • The biosolids produced are significantly smaller in volume than the current methods and are safe for reuse. 

The joint venture has previously delivered two of the country’s largest wastewater treatment plant upgrades (Māngere Wastewater Treatment Plant Biological Nutrient Removal Upgrade and the Pukekohe Wastewater Treatment Plant Upgrade) on time and on budget and those strong relationships, expertise and innovations will be applied to this new challenge. 

Ahead of site works commencing, over a thousand native lizards living at the site were carefully trapped and relocated to protected sites at Moa Point, and in the Miramar Peninsula, like Rangitatau Park, Tukanae Street Reserve, and Centennial Park.  

Construction is now underway with completion expected in late-2026.  

Project Gallery