Alternative water sources
With traditional water resources being depleted, Australian governments and water companies are looking to alternative water sources to meet demand. These alternatives include: seawater, saline groundwater, urban stormwater, and wastewater (e.g. treated sewage effluent).
As shown in the figure below the majority of distributed water, in 2004-05, came from surface water resources. Western Australia is the only state which sources a significant proportion of it distributed water supply from groundwater sources. The figure also shows the volume of distributed water sourced from desalination, which in 2004-05 is negligible. However, this is likely to change in the near future with a large seawater desalination plant completed in Perth in 2006, and several other large desalination plants being built or considered in other states.
Perth seawater desalination plant is designed to produce on average
130ML/day, which is about a sixth of Perth’s water supply requirements.
Origin of distributed water for the water supply, sewerage and drainage services industry only (Source: ABS, Water Account, Australia 2004-05)
There are a variety of water sources that may be supplied as reuse water, including waste water (from sewerage systems), drainage water, storm water or other water providers (i.e. a 'bulk' reuse water supply). Sewerage systems collect and treat waste water to primary, secondary or tertiary levels. Storm water may also be collected using infrastructure separate to sewerage systems and, depending on its intended use, may or may not be treated before being supplied as reuse water. Drainage water is collected in regional collection drains managed by Irrigation/rural water providers. This water may be supplied as reuse water to customers or discharged to the environment. This process is analogous to urban reuse systems, however typically in urban systems the water is treated before supply.
The volume of waste, storm and drainage water collected by water providers for supply as reuse was 414 GL in 2004–05. Of this, waste water amounted to 212 GL (or 51%), and drainage water, 201 GL (or 49%). Water providers in New South Wales collected the most waste, storm and drainage water (193 GL or 47%), followed by Victoria (130 GL or 31%) and Queensland (46 GL or 11%). During 2004–05, urban water providers treated 213 GL of waste and storm water, with Major urban water providers accounting for over half (59%) of this amount. Urban water providers in Victoria treated the most waste and storm water for own use or supply with 69 GL (or 32% of the Australian total) followed by New South Wales with 53 GL (24%).
Origin of reuse water for the water supply, sewerage and drainage services industry only (Source: ABS, Water Account, Australia 2004-05)
Aquifer storage and recovery (ASR)
Aquifer storage and recovery (ASR) is the process of injecting water from the surface into a suitable underground aquifer for storage and re-supply. One of the advantages of ASR is that it can be used to store large volumes of water from wet periods (e.g. storm events) which can be stored with very little evaporation and can then be used at another time of the year when water is scarce. It is a suitable technology for urban environments where surface storage is limited, and demand is seasonal. ASR is likely to become a more common alternative source water supply in future.
Aquifer storage and recovery (ASR) enables stormwater to be stored underground for later recovery during dry periods. The scheme at Rossdale Golf Club was funded by the Victorian Government’s Smart Water Fund as a demonstration site.
Image by Stephen Parsons, sourced from SKM
CSIRO, working with partners, has pioneered research, development and implementation of aquifer storage and recovery (ASR) of stormwater and reclaimed water for irrigation. Their research covers the technical feasibility, public health, environmental sustainability, and economic viability of storage and reuse of water that would otherwise be wasted. Further information is available from their
Water Use and Reuse