Reuse highlighted in WSAA urban water roadmap
The volume of water being recycled by the largest water utilities in Australia has increased by 117% since 1999/2000. In addition, it is estimated that, by 2013, 460 million m³/year will be supplied to Australia's growing cities by desalination plants.These statistics are taken from a new position paper Vision for a Sustainable Urban Water Future, published by the Water Services Association of Australia which outlines a roadmap for national action for the urban water industry based on issues of:
To illustrate the interdependency of all the country's diverse water sources, the paper points out that, as a result of water conservation measures, in some instances around Australia, the volumes of sewage have dropped by up to 40%, which has reduced the yields available from recycled water schemes.
In addition, the paper says, "Given the need to maximise the efficient use of recycled water, it is highly likely that the days of extending sewage collection systems over ever increasing distances to be connected to coastal sewage treatment plants are coming to an end. If the efficient use of recycled water is to be maximised, it is imperative that a reliable recycled water source is available close to growth corridors and industrial precincts, so that recycled water can be supplied without the need for long pipelines and associated prohibitive pumping costs and energy consumption."
Regulatory arrangements for regional treatment plants need to take account of the difficulty of using all available recycled water during the wetter months of the year, where the demand from households and urban irrigation users is likely to be subdued, says the paper. It also calls for studies to be undertaken to determine the sustainability of decentralised systems in commercial or residential developments from economic, energy, environment and social perspectives.
The WSAA also warns about greenhouse gas emissions. "The requirement to increase sewage treatment from secondary to tertiary standard results in a four-fold increase in energy consumption at the treatment stage," the paper states.
"New regulatory approaches should weigh up any incremental benefit of increased effluent quality regulations against the cost of incremental increases in greenhouse gas emissions (both energy related and embodied in materials) required to achieve such standards," it continues. "In general, any changes to environmental regulation should pass the cost/benefit test on a triple bottom line basis."