The completion of a new leachate irrigation system for Central Hawke's Bay's landfill demonstrates the District Council's commitment to the natural environment, Chief Executive Monique Davidson says. 

Councillors, council officers, contractors and local landowners gathered at a socially distanced opening last Thursday. 

Davidson said the completion was another important step forward in "The Big Wastewater Story" and council’s wider Waste Free CHB strategy.

Following the council’s decision in 2019 to invest in an environmental 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.

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.

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."

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