Auckland water treatment plant to be replaced; three options given

Monday, 20 February 2017

Watercare operations manager Priyan Perera explains the need to replace the Huia Water Treatment Plant.

A water treatment plant in west Auckland was built in 1929 and now needs replacing, Watercare says.

The council-controlled organisation is now consulting on three options: replacing the current Titirangi plant, building on adjacent land or building on a site nearby in Oratia.

Operations manager Priyan Perera said that not only is the current plant old, requiring repairs and maintenance, but new filtration technology is needed as the dams contain increasing amounts of cyanobacteria and algae.

Perera outside the aging building facing the road.

'It's an old plant and it wasn't designed to deal with what's coming at it now,' Perera said.

'It's about the future, because the water is going to change and we can see that it has changed already.'

Watercare's three options for replacing the aging plant.

The cost of building a new plant and associated pipes was 'in the $300 million to $400m range' depending on the site and the 'complexity and challenges of construction'.

Drone footage of the Huia Water Treatment Plant and its feeder dams.

Perera said no decision has yet been made about where the new plant would be built.

'We have not made a choice, because we understand that there will be community issues,' he said.

'There's a lot to talk about and we want to communicate with people.'

Watercare spokeswoman Maxine Clayton said community focus groups were held in November 2015.

The sludge removed from the water by the clarification process is black because of the added carbon.

Forty-four potential sites were initially considered, and a Tonkin and Taylor report in June 2016 narrowed eight possible locations down to three.

The report said building on the existing site would require the rest of the water supply network to pick up the plant's capacity while it is rebuilt.

Perera walks above the water treatment plant's 24 clarifier tanks.

The top option was to build on Watercare's land on 130 Parker Rd in Oratia and surrounding properties.

'The site is large, with two alternative water treatment plant locations within the site, and it is located at a very good elevation,' it said.

Extra sand filters have been added to the plant over the years.

'The presence of a Significant Ecological Area across most of the water treatment plant and reservoir sites constitutes a significant hurdle from a consenting perspective and also means the social impacts are potentially high.'

Perera said the Huia Water Treatment Plant in Titirangi was the fourth largest in the country and supplied 19 per cent of Auckland's water.

Its replacement will be one of the biggest water treatment infrastructure projects in the country 'for a while', he said.

* Watercare is holding public information evenings in the area on February 21, 22 and March 1. Go to watercare.co.nz for where and what time.