Substantial water savings achieved through supernatant recycling
Bathurst regional council in New South Wales is set to achieve substantial long-term savings following the installation of a supernatant recycling system.
Thanks to the supernatant recycling system introduced into the filtration plant in the town water supply, Bathurst regional council in New South Wales is conserving potable water and will see substantial savings in the long term.
Installed by Ted Wilson & Sons of Blayney using equipment supplied by CST Wastewater Solutions, the recycle system recovers and disinfects the backwash supernatant – clear liquid that collects above sediment – at the plant. This type of disinfection has proven to be able to recover up to 10 percent of raw water supply, while also avoiding the need for discharge flows into river systems.
Previously, the supernatant from the filtration plant’s three sludge lagoons (where the filter backwash water is discharged) was decanted from the lagoons and discharged. The new system, involving a supernatant pumping station, enables the automatic recycling of supernatant from the sludge lagoons into an in-ground well, and then into the first chamber of a rapid mix tank.
Based on seasonal demand patterns, the wastewater to be recovered from this system is estimated at about 192 megalitre per year, based on a present annual water consumption of 6000 megalitre. The supernatant currently being recycled is 6 percent of the plant flow, and should vary with a projected increase in demand in the future.
Michael Bambridge, managing director of CST Wastewater Solutions, believes backwash supernatant disinfection is a promising solution, even though it’s not used extensively in Australia. “The advantage is that the method recovers up to 10 percent of the raw supply, which reduces the demand on the water storage system and avoids the need for waste flows into the river system,” Bambridge notes.
CST Wastewater Solutions is a member of the Global Water and Energy Alliance, a select group of companies from around the world dedicated to finding solutions in water and wastewater treatment for the recovery of green energy and water.