Fate of water on table


THE fate of Kawerau’s water supply treatment will be confirmed at today’s council meeting.

On January 29, Kawerau District Council elected members voted unanimously to stop chlorinating the water supply, following seven months of sporadic discoloured water in numerous homes and hundreds of complaints.

Following findings from a government inquiry into the Havelock North drinking water issue and encouragements and recommendations from a government minister and ministry chief executive last year, council staff investigated drinking water standards.

Council operations and services manager Hanno van der Merwe said the Kawerau water supply was non-compliant with New Zealand’s drinking water standards in 2018 due to three positive e-coli test results and chlorination was the only feasible treatment that would ensure compliance.

In March 2018, the council resolved to permanently chlorinate the water supply from July 1.

Four days after the chlorination commenced, discoloured water was observed.

“Prior to chlorination, the council had received approximately 40 discoloured water complaints over the previous seven years. Since the introduction of chlorination there have been 142 complaints in five months.”

The Kawerau water supply contains low levels of manganese and iron. The manganese and iron are oxidised by bacteria and become black and red-brown respectively.

“In low levels this is harmless, however, high levels of manganese over the long term can be harmful, especially to children.”

At the meeting last month, scheduled to look at estimates for the next financial year, the council was presented with six options in relation to water treatment – do nothing, stop chlorinating, alternative chlorination options, clean pipes with air scouring, clean pipes with ice pigging or replace reticulation.

After consideration, the council agreed to resolutions that would be confirmed at the next formal meeting.

Chief executive officer Russell George said over the next month, the entire reticulation network would be flushed.

“Engineering staff are also currently working on a trial to gauge the effect of air-scouring pipes. The trial is being conducted on pipes in a non-residential part of the district so will not have any impact on households in the town.

Since the halt, feedback has been mixed, with some residents commending the council for its decision, but with many others expressing frustration around intermittent water discolouration issues.

“Residents need to be aware that halting chlorination is not an immediate solution to the discolouration.

“The chlorination process dislodged bacterial material, and staining from natural manganese in the water, which had built up in the system over many years.”

Mr George said the council would provide updates to the community on the outcome of the trial pipe scouring and the next steps as soon as the information was available.

“We understand people’s frustration and ask for their continued patience while we work through a solution

“Once the discolouration has been remedied, the council will revisit chlorinating the water supply to meet the national drinking water standards.”

The council regulatory and services committee meeting will be held at the council chamber from 9am.