The scheme consists of three advanced water treatment plants – located at Bundamba, Luggage Point and Gibson Island – that can purify secondary treated wastewater to exceed drinking water standards by passing it through seven barriers, including microfiltration, reverse osmosis and advanced oxidation by UV radiation.
The scheme is not currently producing water as South East Queensland (SEQ) is experiencing a high level of water security, which is expected to continue over the next decade and beyond.
In June 2013, Seqwater and the Queensland Government decided to place the Western Corridor Recycled Water Scheme in care and maintenance mode. The decision benefits all water customers in SEQ by helping to limit the annual increase on bulk water charges as a direct saving to households.
The scheme can be restarted when required as one of our drought response measures, assisting with long-term water security for the region. For more information about our operating strategy for the water grid, including the Western Corridor Recycled Water Scheme, see our 30-year Water for life plan.
How the scheme works
Raw water is transferred from wastewater treatment plants. These treatment plants remove a significant amount of impurities and micro pollutants.
Pre-treating involves coagulation, flocculation and the removal of bacteria and phosphorous.
Microfiltration involves passing wastewater through very fine hollow fibre membranes 0.1 to 0.4 micrometres in size (human hair ranges in size from 20 to 200 micrometres in diameter) that remove particulate matter, protozoa and some viruses. After passing through the membrane, the filtered water mostly contains dissolved salt and organic molecules.
Reverse osmosis involves forcing filtered water through a special membrane at high pressure to remove impurities such as dissolved salts, viruses, pesticides and most organic compounds. The membrane acts like an artificial kidney. RO produces water of a higher level of purity than drinking water. It is the same process used to desalinate seawater.
Advanced oxidation exposes the water to ultraviolet light combined with hydrogen peroxide to sterilise and eliminate remaining organic compound traces. The UV intensity is around 300 times that of the sun’s rays.
Stabilisation prevents corrosion of piping and pumping equipment, involving the addition of lime and carbon dioxide to return the water to its original levels of hardness and alkalinity. Disinfection involves adding chlorine, which has the added benefit of preventing biological growth in water pipes and storage tanks.