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Project business partners collaborate on water supply

Local businesses and project partners have teamed up to help Te Hōnonga a Iwi Restoring Rosedale Park set up a reliable system to get water to our bioreactors.

Regeneration expert Matt Cummings from Untangled Landscapes says our 15 bioreactors need a constant water supply to compost the organic material they contain.

“They are designed to allow diffusion of air through the compost, which has a drying effect. But microbes need a certain amount of water present to be active.”

But setting up that supply has been a big logistical exercise requiring support from several of our business partners.

The water supply is coming from two sources – ICB, a retaining and construction company that neighbours the project site, has generously allowed our team to collect rainwater from its roof and Watercare and Ventia are working together to donate and transport a backup supply during dry weather.

One of our plastic intermediate bulk containers (IBCs) has been installed under the construction company offices and diverters on the stormwater downpipes deliver the water from the roof to the storage facility.

A limit switch in this container has been set to turn on a pump once the water level is above 500 litres – the pump will push the water over to fill the IBC tanks on the project site that are watering the bioreactors. The pump switches off when the water level drops to 100 litres.

To supplement the freshwater supply, Watercare has partnered with our project to provide recycled water to the IBC tanks.

It comes from the nearby Rosedale Wastewater Treatment Plant, where it receives full tertiary-level treatment, including the use of UV light to provide disinfection.

Watercare Recycled Water Lead Brendon Dockary says the company has already supplied 5500 litres to the site.

“It’s fully treated wastewater which we refer to as recycled water, so it’s perfectly safe for this sort of use,” says Brendon.

Watercare is in the very early stages of what it believes will be a multi-decadal journey for recycled water.

“Auckland is growing rapidly, and in the 2040s, we’re going to need a new water source to ensure we can keep up with demand.

“Following the lead of dozens of other countries around the world, we are looking into developing recycled water as an alternative source to help increase both our security of supply and to provide for our growing population.

“Small community-led projects like this are a fantastic opportunity for us to slowly dip our toes in the pool of recycled water to start educating the public and to prove that it’s a safe and valuable resource, so it’s a win-win really.

“The fact that by doing this, we also get to play a role in the restoration of a local waterway is also a huge honour. Water is life and being able to improve the condition of this stream will not only improve the lives of the locals who get to enjoy it, but also the flora and fauna who live within it.”

Essential services provider Ventia has signed up to transport the water from the Watercare station to the site as needed.

Ventia Environment and Sustainability Advisor Chloe Brown says Ventia’s approach encompasses the social impact the organisation has with its people and communities, its environmental footprint and the way it conducts its business.

“The Rosedale restoration project is right in our backyard - in fact it is only five minutes from one of our depots, from which we service our Auckland Council facilities maintenance contract.”

Ventia supports the work the project is doing to take ecological responsibility to work towards mitigating climate change. “It is also focussed on improving the wellbeing of the local environment in order for our local people to be well,” Chloe says.

“The restoration model enables the development of greater social equity, placing mana whenua as a key stakeholder and primary partner within the project.”

Once the water is on site, it is stored in the IBCs, then piped to the bioreactors.

“There is a 25mm ‘trunk’ line running from the tanks, through our control solenoid, around the carpark and all the way along the top of the row of reactors, with 13mm ‘branches’ coming off in a t-shape to the dripline for each reactor,” says Matt.

“We water the reactors for a minute each day using the driplines to spread the water around as evenly as possible, and without wasting any like we would with a spray nozzle.”

Watercare’s Brendon Dockary says that by using recycled water and rainwater, the project is freeing up potable water (safe drinking water) to be used for genuine potable reasons elsewhere.

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