Project Pure sludge under consideration
Natural drying system under consideration for Project Pure sludge
An innovative natural system for turning sludge into fertiliser will also be a money-saver for Wanaka ratepayers if “Project Groundswell” gets the go-ahead.
QLDC is proposing a partnership with Fulton Hogan that would transform sludge from Wanaka’s Project Pure wastewater plant into fertiliser at a natural solar drying facility near Luggate. Once dry, the material would be ploughed into the ground at two neighbouring properties and would improve the fertility of the soil, which would then be used to grow silage or hay.
At present the nutrient-rich sludge is trucked over 70km and buried in the Victoria Flats landfill, where it is producing methane and has no environmental benefit.
Erik Barnes, QLDC’s General Manager of Infrastructure and Assets, said that the proposal to develop the solar drying facility would be discussed with the Luggate community at a drop-in information session tonight (Thursday 26 September). Iwi, environmental groups and other local interest groups are also being consulted.
“This is a great opportunity for the district to make some positive changes in how we manage and reuse our waste. We've had great feedback on the proposal so far, because of the environmental and financial advantages of the natural drying system,” Mr Barnes said.
The solar drying facility would use German “WendeWolf” technology, which is widely used in Europe and North America, and has also been installed in Toowoomba, Australia. The simple greenhouse-style building uses a combination of vents, flaps and fans to keep air flowing inside and dry the sludge naturally. As the moisture evaporates, the volume of material reduces so that for every 1000 tonnes of sludge brought to the facility, between 100-200 tonnes of dry matter will be left.
If the project goes ahead, it will provide annual savings of $113,000, which is $23.54 a year for every household in Wanaka and Albert Town connected to Project Pure. There is no capital cost to QLDC because Fulton Hogan will build and operate the drying facility, and the Council will pay a set rate for every tonne of sludge dried there.
Fulton Hogan will apply for consent to construct the drying facility and to apply the dry material to land. The two neighbouring landowners have already given their approval as affected parties.