SA Water has strategically invested in membrane filtration plants, which represent the future of water treatment. The technology is mature and very competitive against traditional sand filtration processes.
Typically, a membrane plant requires 30–40% less footprint area than traditional sand filters. Membrane filters are made of specialised polymers with very small pores. The pore size of membrane filters is typically less than 0.1 microns, which is about 50–100 times smaller than the thickness of a human hair. Membranes provide a direct physical barrier to waterborne pathogens, such as Cryptosporidium, which is resistant to chlorine disinfection. Pre-treated clean water is sucked through the membranes at low pressure, much like the suctioning action through a straw. Membrane filters are regularly backwashed with air and clean water to remove accumulated solids.
Chemical cleaning is required on a monthly basis to remove material not effectively removed by air and water backwash. Typical membrane life ranges from 3–8 years depending upon the quality of the raw water. SA Water employs membrane filtration at 11 facilities treating River Murray water, including Mount Pleasant (since 2000) and the Country Water Quality Improvement Program Stage 3 plants (since 2008).
A listing of the water treatment plants that employ membrane filtration can be found here .