Infrastructure upgrades  |  16 Sep 2019

The Christchurch City Council is no longer investigating managed aquifer recharge as an option for disposing of Akaroa’s treated wastewater.

It investigated managed aquifer recharge as a possible disposal method at the request of the Akaroa treated wastewater reuse options working party, established to assist the Council to investigate and consult on options for the beneficial reuse of treated wastewater.

At present, the town’s treated wastewater is discharged into Akaroa Harbour, but the Council has made a commitment to explore alternatives to discharging wastewater into the harbour.

Managed aquifer recharge is generally used to augment water sources where aquifers have become depleted and/or where there is a risk of saltwater intrusion. In this case it was suggested that highly treated wastewater could be fed into Akaroa’s aquifers, or groundwater, as an alternative to a harbour discharge.

The Council’s acting head of Three Waters and Waste, John Moore, says investigations have been discontinued because managed aquifer recharge with treated wastewater would pose a risk to the town’s drinking water supply.

“If treated wastewater is injected into Akaroa’s groundwater, there’s a risk it could enter the bores used to supply drinking water,” Mr Moore says.

“In light of recent central government moves to strengthen drinking water standards, it is not a risk we are willing to take – protecting the community’s drinking water is of paramount importance.”

Mr Moore says he is confident staff have investigated every practicable method for disposing of Akaroa’s treated wastewater and there will be no further investigations.

“Staff have investigated a range of methods suggested by the community, including irrigation to land, an ocean outfall, piping the wastewater elsewhere, deep-bore injection and managed aquifer recharge,” he says.

“It’s time now to bring investigations to a close and consult the community on the most effective options available,” she says.

Three options are being prepared for consultation with the community before the end of this year.

“We hope to share these options with everyone in Christchurch and Banks Peninsula after the elections so that the new Council can make a decision early in 2020,” Mr Moore says.