Pukekohe Water Treatment Plant commissioning underway

Watercare’s new Pukekohe Water Treatment Plant is being commissioned this week before it goes into service over Labour Weekend.

The plant will provide up to 5 million litres a day from two bores about 270 metres below ground.

Watercare acting chief executive Marlon Bridge says the bores’ return to service has been accelerated as part of the company’s response to this year’s record-breaking drought.

“To have this new source come online over Labour Weekend is fantastic timing as it’s a time of year when we normally see water use start to climb.

“Our Hūnua dams in particular are still recovering from this year’s drought, so we have been minimising the abstraction from these dams to allow them to replenish.

“Being able to treat and deliver up to 5 million litres a day from an underground aquifer means we can continue to ease the pressure on these dams over summer.”

The Pukekohe plant is the first of two new water treatment plants Watercare is building to supplement Auckland’s water supply in the wake of the drought. It took four months to build.

Watercare head of operations excellence Priyan Perera says the $11.5 million modular treatment plant is simple in design but uses sophisticated technology to produce the highest-quality water.

“We pump the water from an underground aquifer with two bores about 270 metres deep,” he says. “We then dose it with chlorine and use ultra-filtration membrane filters to remove iron and manganese.

“While chlorine disinfects the water, we also use ultra-violet light dosing units to provide additional disinfection. This multi-barrier treatment process means we will be producing crystal-clear water of the highest quality.”

The bores and old treatment plant, which Watercare inherited when the Supercity was formed in 2010, had been out of service since 2013. The old plant, built in the 1970s, lacked processes to remove iron and manganese and was not up to standard.

“The new treatment plant addresses the shortcomings of the old treatment plant, so the people who live and work in Pukekohe can be confident their water will be of an extremely high quality, and will look and taste great,” Perera says.

Watercare’s work to expand existing treatment plants and build new ones will supplement Auckland’s water supply with an additional 40 million litres a day before Christmas.

Bridge says that puts us in a strong position ahead of the hotter summer months.

“Forty million litres a day is a huge amount of water. To put it in perspective, it’s about the same as the volume of water produced each day at two of our Waitākere dams, and it’s enough to meet the needs of 130,000 people.

“This extra water, combined with continued savings from our water-conscious customers, is why we are confident we will get through summer without the need for more severe restrictions.”