Two Central Otago landowners are starting to apply for resource consent to use sewage sludge on their farms in response to the Queenstown Lakes District Council seeking expressions of interest from those keen to use sludge from Wanaka's Project Pure waste water treatment plant.
In a report to last week's utilities committee meeting, strategic project manager Martin O'Malley said there were eight responses, including from two landowners based in Tarras and Hawea.
He said the landowner option was prioritised because it required no extra treatment.
"I am particularly excited that there are landowners interested in looking further at how this material could potentially be used," he said.
Both landowners had suitable locations and farming practices to use the material.
A representative from the Otago Regional Council (ORC) and a land treatment expert from CPG NZ Ltd attended meetings to give advice on consenting issues and how applying sludge could work.
"Further work is required over the next few months to negotiate a formal agreement with the landowners and to prepare the application for a consent with the ORC," Mr O'Malley said.
QLDC solid waste manager Stefan Borowy told the utilities committee the land owner in Tarras was applying for consent.
Sludge would continue to be disposed to landfill until a formal agreement was reached and a consent granted.
Sludge waste would make up about 10% of the district's waste by 2014, a percentage similar to the proportional amount of construction and demolition waste.
It costs $229 per tonne to dispose of sludge to landfill, or about $16,000 a month for 70 tonnes.
"By dumping sludge in the landfill there is the potential that the moisture within the sludge and the nature of the material will give rise to methane gas production in the future.
This may result in additional future costs associated with the collection and treatment of this methane gas," he said.
Cr Gillian Macleod questioned whether there could be mercury in the sludge used on the land, but Mr Borowy said the risk of mercury contamination would be minimal.
Sludge from Queenstown's proposed waste water treatment plant Project Shotover would eventually also be used by the landowners.
Consents for Project Shotover are subject to Environment Court appeals.
"When we get Project Shotover included it is unlikely, but not impossible, that the same sites will be used.
We will most likely be asking for expressions of interest again from landowners in the area, including the Wakatipu," QLDC general manager infrastructure services Mark Kunath told the committee.
