Central Hawke’s Bay District Council celebrates completion of leachate to landfill project

Central Hawke’s Bay District Council reached a proud environmental milestone this week with the completion of the new leachate irrigation system at the district’s landfill.

Councillors, council officers, contractors and local landowners gathered at a socially distanced opening on Thursday 7^th October 2021 where Chief Executive Monique Davidson said the completion was another important step forward in The Big Wastewater Story and council’s wider Waste Free CHB strategy.
“The completion of this project demonstrates council’s commitment to our natural environment.”

Deputy Mayor Kelly Annand said: “We are proud to continue our partnership with Higgins who have once again supported us to deliver a project that aligns with our environmental aspirations.”

Following council’s decision in 2019 to invest in an environment focussed solution, an approach was adopted where the contaminated water is recycled through irrigation and placed back into completed areas of the landfill.

This system replaces the need to transport leachate to the wastewater treatment plant, reducing the operational costs associated with disposing leachate and alleviates pressure on the plant, a key piece of the puzzle in our wastewater improvement programme.

Councillor Brent Muggeridge said: "10 years on from this project being initiated, we are able to achieve our community outcomes of being environmentally responsible and building durable infrastructure."

Construction began in 2019 and saw the removal of the old, damaged leachate pond followed by the installation of a new pumping system, pipework and pond which now provides 2,300m³ of storage for leachate under normal operation and up to 3,100m³ in emergency conditions. Leachate will be stored in the pond when it cannot be irrigated, in most cases overnight and during wet weather.

Leachate will seep through the landfill and travel via a gravity pipeline into the new pond, where it will be pumped through the new system, then irrigated back at slow rates, allowing time for the water to evaporate and transpire from the surface while preventing overflow.

The pond has also been lined with a geomembrane to stop leakage back into the ground.

On average, the landfill produces 7,500-10,000m³ of leachate per annum.

To learn more about the project and Central Hawke’s Bay District Council’s vision for a waste-free future, visit https://www.chbdc.govt.nz/our-district/projects/the-big-wastewater-story/leachate-to-land/.

11 October 2021

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