Gas Management System for Colson Road Landfill

05 July 2016

A new system will be installed at the Colson Road Landfill to counter an ongoing odour problem.

Since 2014 there have been 18 odour complaints about the landfill, often on cold mornings.

At tonight’s (Tuesday) Council meeting, New Plymouth District Council approved the development of a gas management system that will flare off the odours and methane, with the costs being met by the Solid Waste Development Fund.

“We believe the problem is caused by having a landfill near the end of its life,” says Manager Water and Wastes Mark Hall.

“The landfill is in a gully and for years the waste had been below the level of the surrounding land, trapping the odour in place, but now the waste has mounded up to be level with the surrounding land and the heavy air in the colder weather travels down the valley.”

The Council has approved a three-stage gas management construction project, with the success of odour mitigation being evaluated after each stage. If an early stage successfully solves the issue, the following stage will not be built.

“It’s likely that we’ll need both stages one and two built, but we won’t know if stage three is needed until we monitor the effectiveness of the first two stages,” says Mr Hall.

All three stages are estimated to cost $1.22 million dollars: $665,000 for stage one, $285,000 for stage two and $270,000 for stage three. The final cost will be known after the detailed design is completed.

In recent years NPDC has received two abatement notices and a fine from Taranaki Regional Council due to odour and associated site management issues, and there is a risk of prosecution if NDPC does not manage the odour appropriately.

The Colson Road Landfill is due to close in June 2019, however the landfill will continue to produce gas for up to 30 years. The gas management system will provide effective treatment for more than 10 years, after which time it is expected that landfill gas generation will have reduced significantly and will no longer require treatment.

Construction of stage one is expected to begin before the end of the year.

  • The Solid Waste Development Fund is money generated from the landfill’s operation.