In his submission to the council's 2019-20 annual plan, environmental engineer Dave Hanan said it made no financial sense to abandon the Green Island landfill when its consent ends in 2023.
Mr Hanan is the council's former solid waste engineer and is now the manager director of environmental consultancy firm GHC Consultants.
In 2016, there was an estimated 1.6million cu m of capacity left at the landfill which gave it an estimated further 21 years of life, he said.
Instead of opening a new landfill at Smooth Hill, south of Allanton, the council should obtain a 20-year resource consent extension for the Green Island landfill which he estimated was worth at least $345million.
The council should still explore the possibility of the Smooth Hill site and obtain a resource consent but keep it for when the Green Island landfill had been used to its maximum capacity.
The Otago Regional Council is responsible for granting an extension.
Part of the issue was the contract the council had with Waste Management which incentivised the company to fill the landfill with as much waste as it could. A solution would be to renegotiate the contract so the company was paid a lump sum rather than by the amount of waste entering the site.
The DCC has started a review of the city's waste management which will include a detailed business case for changes to rubbish collection, including a new landfill at Smooth Hill.
