Utilities to recharge aquifers with recycled water
Posted 29 July 2016
Water Corporation’s Groundwater Replenishment Scheme, which will swing into effect at the end of this year, is already set to recharge aquifers with up to 14 billion litres of water annually.
But an expansion of the scheme has the potential to double these already impressive recharge amounts.
“Construction of the first stage of the Groundwater Replenishment Scheme began in October 2014 and is due to be completed by the end of this year,” said Water Corporation Assets Delivery General Manager Mark Leathersich.
“Last week, it was announced the capacity of the first stage of the scheme would be doubled to be able to recharge 28 billion litres of water each year.
“The expansion will include the construction of offsite recharge bores and an associated pipeline, to the east of Lake Joondalup. Recharging the additional water off-site will help to keep groundwater levels sustainable.”
Leathersich said the scheme is part of the utilities broader Water Forever initiative, a long-term plan to secure water supplies, and is expected to safeguard Perth’s drinking water.
“It is a secure, climate-independent source of water that, once expanded will have the capacity to supply the same amount of water used by 100,000 homes each year,” he said.
“Groundwater replenishment could supply up to 20% of Perth’s drinking water needs by 2060.”
Following treatment methods tested over a three-year trial, the chosen aquifer is recharged with water, which remains there until withdrawn again years later.
“During the trial more than 3.8 billion litres of highly treated recycled water was recharged into the Leederville aquifer,” Leathersich said.
“The trial was an overwhelming success, with all of the 62,300 water quality samples taken meeting strict health and safety guidelines.”
Leathersich said the water pumped back into aquifers stays there until years later, when groundwater is extracted once more.
“Highly treated wastewater from the Beenyup Wastewater Treatment Plant in Craigie is processed through three water treatment methods to further treat it to the equivalent of drinking water quality, before recharging it into the ground,” Leathersich said.
“This water, which is then drinking quality, is recharged into the aquifer. The water will remain in the aquifer for decades before it is drawn out at another location, treated at a water treatment plant and added to the water supply scheme.”
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