Major Projects
Water purification and the processes proposed
ACTEW has been investigating and proposes to continue to examine proven advanced technology to treat wastewater to a standard safe for human consumption. As yet, a water purification scheme for drinking purposes has not been approved for the ACT. However, ACTEW Corporation is designing a Demonstration Water Purification Plant. The water from this plant will not be added to our drinking water supply.
Technology used
ACTEW considered several treatment process options to provide a multibarrier approach to water purification. In 2007 an expert panel on health considered the suitability of each of the treatment process options available. ACTEW then adopted the expert panel’s preferred treatment process, which includes membrane filtration, reverse osmosis and ultraviolet disinfection and advanced oxidation. Membrane filtration uses hollow fibre membranes with fine pores to remove particles and micro-organisms from water. The membrane surface acts like a very fine screen to retain the micro-organisms; similar to a screen door that retains insects, but the membrane is at a much smaller scale. This step removes microscopic particles, contaminants and pathogens.
Reverse osmosis is a water treatment process that uses pressure to force water through a membrane to separate it from dissolved salts. The membranes have very small pores, so small that most of the dissolved salts are also removed.
The water would then be treated further using ultraviolet disinfection and advanced oxidation. Ultraviolet light is used to disinfect water and is effective at destroying micro-organisms such as giardia, cryptosporidium and other pathogens. Oxidation is used to breakdown chemical compounds.
Should the ACT Government ask ACTEW to proceed with a full-scale water purification scheme for the ACT, the purified water would be added to the Cotter Reservoir. There the water would mix with the natural runoff in the catchment.
Before being piped to our taps, water from the Cotter Reservoir receives further treatment at the Mt Stromlo Water Treatment Plant. At this treatment plant water undergoes coagulation, flocculation, filtration and floatation, chlorination and UV disinfection to ensure that it is of the highest standards when it reaches our taps.
Learn more about the Design of a Demonstration Water Purification Plant here.
Learn how you can have your say on water purification here.
Learn more about the health and safety of water purification here.