Chlorination prompts debate

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By ROBYN BRISTOW

A Hurunui District councillor says Hanmer Springs has been “shafted” over the council’s decision to chlorinate the town’s water supply.

Cr Jason Fletcher, who is the Hanmer ward representative and a member of the Hanmer Springs Community Board, says the community board had made it clear it did not want permanent chlorination of its water supply and says the decision has been made without consulting the residents.

He was commenting on the council’s decision to chlorinate all council water supplies across the district to ensure “consistently safe drinking water” for all residents and visitors. The decision has also drawn opposition on social media.

Mr Fletcher says chlorinating the water is OK for short periods, such as when there is high turbidity in the supply, but “we don’t want it fulltime”.

But the council says there has been a number of E.coli transgressions in the Hurunui district which had the potential to “adversely impact residents health”. Fulltime chlorination would give water systems “resilience”.

“If a contamination outbreak occurred it would be extremely damaging, not just to local residents but also to visitors and tourists,” the council says.

The decision means all council water schemes will be treated with chlorine or MIOX, with the remaining five being progressively brought on stream over the next few months.

Amberley township, Amberley Beach, Leithfield Beach and Hanmer Springs have had their water supplies temporarily chlorinated over the last six months and this will now be made permanent.

Leithfield Village and other residents connected to the Leithfield supply, along with Culverden, Hawarden/Waikari and residents connected to the Racecourse bore will have their water supply chlorinated from September, on a rolling basis.

Cr Fletcher has called a public meeting in Hanmer Springs on August 14 to discuss chlorinating the village’s supply. A meeting has also being organised in Waikari on August 15.

“Potentially we should be looking at ways of protecting our catchment area or taking water from bores,” says Cr Fletcher.

He believes the council’s decision to “globilise” all its water schemes was “unfortunate” and had taken away the local decision making through the community board. Also setting up council committee’s with core members had added to the problem.

“Even if I had been at the Infrastructure meeting, where this was decided, I could not have voted because I am not a member of that committee.” He believes the council should have dealt with chlorination under its Significant and Engagement policy, where consultation was required.

Infrastructure services delivery manager Dan Harris says that permanent chlorination of all council supplies provided the best option to ensure public health and safety.

“Following a number of transgressions entering through the pipelines over the last few years we decided that permanent chlorination is the best solution. This ensures a safe supply from the intake point, right through the pipes to the taps,” he says.

The Hurunui community had been consulted as part of the decision several years back to set aside around $18 million to ensure all its water supplies complied with the New Zealand Water Standards by 2024 and guidelines.

“This is the first step,” says Mr Harris.

Chlorination was the best technology available “currently”. Christchurch City did not chlorinate its water but had an “army of people” ensuring the drinking water was safe on a daily basis.

An excerpt from the drinking water guidelines emphasises the integrity of well managed distribution systems is one of the most important barriers that protect drinking-water from contamination and says too often the distribution systems receive too little attention.

The guidelines says the most common faults are “cross-connections and back-siphonage”, burst or leaking water mains, contamination during storage, poor practices during water main repair and installation of new water mains, pressure fluctuations and leaching from pipework. They say a significant proportion of faults are “unknown” and outbreaks of illness have been associated with low water pressure and intermittent supply.

Mr Harris says chlorination ensured safety from contamination, managing the risk and giving the system “resilience” due to system failure or “ground movement”.

“Our aim is to keep chlorine levels as low as possible while meeting the drinking water standards.

“Odour and taste concerns generally arise at 0.6 – 1.0mg per litre. Our rate will be around 0.3mg per litre, which is much lower than the maximum allowable level of 5mg per litre.”