THE THERMAL DRYING FACILITY (TDF), LOCATED IN NEW PLYMOUTH, SERVES TO REPLACE AND UPGRADE THE AGEING THERMAL DRYER FACILITY AT NEW PLYMOUTH DISTRICT COUNCIL’S (NPDC) WASTEWATER TREATMENT PLANT, WHICH WAS NEARING THE END OF ITS OPERATIONAL LIFE.
The project replaced the previous 20-year-old facility that turns sewage sludge into fertiliser and sees up to 25 per cent of the natural gas used to run the dryer replaced by hydrogen.
| Funding Programme | IRG Programme |
| Project Owner | New Plymouth District Council |
| Infrastructure Type | Wastewater Treatment Plant |
| Government Funding | $37 million |
| Total Project Cost | $59.3 million |
| Project Completed | November 2025 |
The dryer facility is responsible for drying the biosolids from the wastewater treatment plant to produce a fertiliser product for the market. The project comprised civil and structural works involving roading, building erection, mechanical installations, and electrical works.
The new Thermal Drying Facility will run on a blend of hydrogen and gas and will prevent the number of biosolids sent to landfill. The facility uses advanced technology to dry sludge and turn it into Bioboost fertiliser, which can be reused for land rehabilitation and will ensure they are 100% beneficially reused.
Key components include:
- The building facility, surrounding equipment, and silos span an area of approximately 1600m2.
- The TDF building includes a single bay structure to accommodate the drying process.
- The eastern corner of the building houses four silos, which are located at a certain height to allow for material disposal into trucks.
The project has delivered strong economic and employment benefits to the New Plymouth region, using local engineering and construction firms when possible. This project is important for the community as it replaces an existing thermal dry facility which is coming to the end of its design life.
This will futureproof wastewater services for New Plymouth locals and provide ratepayers with a high-quality water service that priorities health and the environment. The project marks a significant $37 million investment into the area by the Government’s Infrastructure Reference Group (IRG) fund.
