A council committee is to consider stockpiling 12,000 tonnes of sewage solids slap-bang below Queenstown Airport’s main runway.
The sewage stockpile proposal goes before the Queenstown Lakes District Council’s infrastructure services committee tomorrow (Tuesday) – and it comes with a powerful incentive.
Project manager Martin O’Malley, who’s recommending the idea, says stockpiling the 12,000 tonnes of poo on the Shotover Delta will save QLDC nearly $3 million.
The solid sewage would be spread over a large area of the delta, below and just south of the main airport runway, close to the Kawarau River.
About 70 per cent of aircraft coming into Queenstown Airport land from the delta end of the runway and the stockpile would presumably be visible to passengers on the left-hand side of incoming aircraft.
The delta has also been earmarked as a significant recreational area by the council – long-term plans include trails and walkways, picnic areas and dog-exercise zones.
O’Malley says the big saving would come from not having to dump the sewage sludge at the council landfill in Gibbston Valley – that would cost $4.1m, while using the delta as a dump will cost just $1.2m.
If councillors buy the idea, “the plan would be to leave the [sewage] material as long as possible…and then potentially use the material for the rehabilitation of the delta”, he proposes.
The possibility of a pong will be a perceived problem for the public, O’Malley predicts.
“The potential for odour is recognised as being of the most concern for people who live and work in the vicinity and also those that use the area recreationally.”
However, council staff visited a similar scheme in Hokitika late last year and “were satisfied that the odour generation as a result of the operation was minimal”, O’Malley says.
If trials on the delta result in sewage odour or other problems becoming insurmountable, or if councillors reject his recommendation outright, O’Malley has a Plan B.
The fallback would involve temporarily stockpiling the poo on the delta and drying it out mechanically before trucking it to the landfill.
This would cost $1.6m, about $400,000 more than dumping it on the delta permanently.