The Press. 4-2-2012
An engineer who moved to Christchurch for the earthquake rebuild is hoping household water recycling will become a fixture of the recovery.
Steven Roberts, of Watersmart, installs systems to recycle grey water – from showers, washing machines and dishwashers – which can then be used to water gardens.
Christchurch’s quake-damaged water infrastructure has been stretched this summer and a level 3 restriction limiting garden watering to alternate days is still in place.
Roberts’ system collects water from a shower or washing machine and feeds it into a garden irrigation system. Users can choose to divert the water for the garden or send it straight to the wastewater network. Roberts said the system could ease the burden on the city’s fresh-water supply during summer and the need for higher-capacity infrastructure in the future.
“You’d think it’s a no-brainer but we’re spoilt in New Zealand with water.”
The blank canvas presented by the large areas of the city to be rebuilt was a perfect opportunity, he said.
“There are not many times in New Zealand you see 20,000 homes needing to be built in a couple of years,” he said. “You can retrofit, but the easiest time to install is when you’re building a new home.”
Christchurch City Council water and waste manager Mark Christison said a grey-water irrigation system had its place but was “no silver bullet” for the city’s water restrictions.
“Health professionals have reservations about how you use grey water. Where you’ve got plenty of land, that’s quite a safe application, but where you get into much higher density of living, you do have to be careful how you use these products,” he said.
“It’s hard to see the merits of justifying modifying plumbing on houses to be able to collect it safely.”
A more realistic option for many people would be better water storage, he said.
He also cautioned: “The amount of water you can store on a 600 [square metre] section is not huge.” The council had been considering grey-water reuse before the quakes, Christison said. A wastewater reuse demonstration project at its water-treatment plant was planned for 2018-19.