The $455,000 "biosolids" project is designed to reduce the cost of taking sludge to landfill, which costs about $213,000 annually and is forecast to rise by up to $40,000 by 2013.
The land application option, which would have a yearly monitoring expenditure of $36,460, was carried at yesterday's meeting of the council infrastructure services committee.
The council has received applications from two farm owners near Luggate who want to use sludge from Wanaka's Project Pure wastewater treatment plant on more than 600ha of their land.
Council solid waste manager Stefan Borowy would not identify the landowners or locations of the farms pending a directive from the committee.
Project Pure was discussed in a public excluded session after the committee meeting.
The council defines sludge as a byproduct of mechanical sewage treatment composed of about 80% organic content moisture, which can an contain trace elements and heavy metals.
Other options included in a report tabled to the committee were outlined although Mr Borowy and strategic project manager Martin O'Malley had chosen the application as the "recommended option."
Alternative solutions included "ag bag composting", which 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 ag bag option would cost $176,000 from the 2011-12 capital budget with a $206,960 operating budget for five years, decreasing to $137,960.
Central Wormworx had approached the council seeking to construct a worm farm, which would have required a heated pad with waste material turned every three to seven days for up to 40 days.
Worms would convert the organic material into wormcasts, which could be broken down into readily available nutrients.
The Wormworx option would cost $385,000 from the 2011-12 capital budget plus $3750 in design costs with yearly running costs of $250,000.
Advetec (NZ) Limited had proposed installing a twin chamber unit at the Project Pure site, where the sludge would be introduced to a blend of plant matter to "stimulate the indigenous bacteria and increase metabolic processes and respiration to eliminate the material".
Advetec was manufacturing a trial unit, which would arrive at the Project Pure site in April. The trial would be conducted at Advetec's expense.
The Advetec option would cost $575,000 from the 2011-12 budget with yearly running costs of $101,658.
Despite the recommendation, the report said the ag bag option and "potentially" the Advetec solution could be revisited if the land application resource consent failed.
