The scheme consists of three advanced water treatment plants – located at Bundamba, Luggage Point and Gibson Island – that 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 very high level of water security, which is expected to continue over the next decade and beyond.
In June 2013, Seqwater and the Queensland Government made a decision to shut down the Western Corridor Recycled Water Scheme. The decision is already benefiting all water customers in SEQ by helping to limit the annual increase on bulk water charges as a direct saving to households.
We will manage the closure to ensure the scheme can be restarted when required, ensuring long term water security for the region.
The water purification process
Raw water is transferred from wastewater treatment plants. The 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 to prevent biological growth in water pipes and storage tanks.