The search for solutions to an accumulation of sludge is looking promising, solid wastes manager Stefan Borowy told the Queenstown Lakes District Council infrastructure services committee this week.
Mr Borowy reported seven parties had indicated they could come up with three or four proposals each for disposing of sludge from Wanaka's wastewater plant, Project Pure.
The council's request for proposals allowed for flexibility for the interested parties to submit ideas based on solutions other than composting, he said.
Sludge is deposited in the Victoria Flats landfill at Queenstown, which costs about $213,000 annually and the total is forecast to rise by up to $40,000 by next year.
The council has stepped back from an earlier proposal to spread sludge on farm land and recently explored several other options, including "ag bag composting".
This would require a covered concrete pad with a leachate collection and storage system. The sludge would be mixed with shredded green waste and fed into a high-density polyethylene bag.
After six weeks, the material would be screened and the fine compost material used by the Parks and Reserves team in gardens and reserves around the district.
The deadline for proposals is March 2.
