Alternative Water Supply
An alternative water supply is commonly recognised as being a water supply fed from an alternative water source rather than a mains water source (ie drinking water source). In industry, this typically include supplies fed from water sources such as filtered roofwater, treated stormwater or recycled wastewater.
Alternative water has long been a source of supply for industrial facilities in regional areas isolated from a mains water supply. In urban settings however, mains water has been the traditional water supply to industry.
Historically, drinking water has been used to supply nearly all water demands in urban Australia, regardless of whether the demands required drinking grade water. This was possible when community concern for water security was low and water utilities sought to maximise customers and water sold.
As population growth and changing rainfall patterns shift the traditional supply and demand balance, and ageing infrastructure coupled with more dense development and increasing construction costs threaten the abilitiy of water utilities to service all demands, alternative water supply has become a strategy that is promoted by water utilities to manage demand growth.
Many large non-drinking water demands in Australian industry, such as processing and cooling demands, are reliant on the drinking water supply system as a legacy of past water supply practices. Industry therefore provides a significant opportunity to save drinking water through alternative water supply. Industrial precincts offer:
Large non-potable water demands which can deliver substantial drinking water savings;
While households have also traditionally been supplied with drinking water for all demands, it is generally not feasible to retrofit households with an alternative water supply for internal use. Rainwater tanks are now common for outdoor use and new developments in some urban areas are supplied with a non-potable mains water supply. Residential precincts such as large apartment blocks do however offer opportunities for targeted alternative water supply.
The evolution of alternative water supply in Australian industry is further summarised in the timeline below.
Roofwater harvesting provides a supply of high quality water suitable for use in non-potable applications such as toilet flushing and landscape irrigation with minimal treatment. More