The new facility is a critical piece of infrastructure for Wellington. Expected to be operational in 2026, it will reduce the volume of sludge being taken to landfill by 80 percent.
Sludge is the solid waste produced from the wastewater treatment process. It contains microbiological contaminants that need to be disposed of in a well-managed way. Its high moisture content means it is difficult and expensive to transport and dispose of.
One million litres of sludge are piped to the Southern Landfill sludge dewatering plant, partially dried, and about 45 tonnes of solids buried each day. This process is unsustainable if the Council is to meet its target of becoming net-zero carbon capital by 2050.
The new facility will break that link between sludge and landfill, reduce carbon emissions, minimise odour, increase the resilience of the overall sludge management process, and align with mana whenua values.
Wellington City Council will apply for funding through the Infrastructure Funding and Finance Act 2020 (IFFA), as outlined in the 2021 Long-Term Plan (LTP). IFFA applies a levy on beneficiaries (in this case ratepayers) to pay the cost of financing over time. The Council will apply for core funding amount of $299m from IFFA to be paid back over 30 years. The levy will be calculated based on the latest capital values (CVs) with commercial ratepayers contributing 25% of the total levy requirement. Residential ratepayers will contribute 75%.
Ratepayers directly connected to the Moa Point facility (generally, properties in Johnsonville and to the south) will cover 70% of the levy requirement, with all City Council ratepayers covering the remaining 30%. The levy will start in 2024 at 25% of the total, increasing to 50% in 2025, 75% in 2026, with the full levy being paid in 2027, when the plant is fully operational.
Directly connected residential properties with a CV of $1 million should expect a levy in the range of $281-$321 in 2027, with directly connected commercial properties paying between $417-$476. Other residential properties will pay between $73-$83 per $1 million of CV, with all other commercial ratepayers paying between $108-123 per $1 million of CV.
Construction on the sludge minimisation facility, to be built on land adjacent to Stewart Duff Drive at the southern end of the airport, is expected to start in mid-2023, with the project completed in 2026.