The future of water.(Environment)

READY ACCESS to both fresh water and energy will become an increasingly important consideration for communities and nations in a likely turbulent twenty-first century undergoing climate change. In Australia the potential availability of around 4500 kilolitres of stored water per person has now due to the drought decreased to around 1500 kilolitres. And the energy cost of "networking" this water from one part of this huge country to another through pipes is enormous. For example, to reticulate northern Australian waters to Perth would cost around $6 per kilolitre.

Speaking at a conference of the Committee for the Economic Development of Australia recently, the Prime Minister, John Howard, criticised the states for "blame shifting" on water management. He highlighted their failure to use dividends from the state-owned water companies to build new reservoirs and to introduce new measures for water production such as recycling and desalination. He went on to say that "in many cases, water restrictions, which are held out as designed to protect and preserve a scarce resource, have got more to do with protecting the cash flows and dividends of government-owned water utilities".

Without doubt, globally but especially in Australia, the technological production of fresh and potable water will become an absolute imperative. The source of this pre-treated water can range from oceans, rivers and aquifers to stormwater run-off and raw effluents from industrial, mining and community and municipal wastes. The technologies used will range from filtration and ion exchange through electro-dialysis and reverse osmosis to various forms of thermal distillation. The domestic collection of all rain water and the recycling of "grey" water should now be encouraged by all state and municipal governments and facilitated by sensible and appropriate architectural design and building construction.

The choice of methods will be dependent on the concentration and physical and chemical properties of the "effluent loading" and the volume or throughput of the water product required. One thing is certain--the end product will be pure and the community will not need to worry about possible health effects. This guarantee will hold whether the impurities or "total dissolved solids" are a few hundred parts per million--as in say mine water--or up to 40,000 parts per million, as in sea water.

For small inland communities and mining operations the treatment of effluents and mine tailings will undoubtedly be drawn from experience derived from hydrometallurgy. Filtration and ion-exchange technology will be used to recycle waste water from municipal and industrial effluent at a relatively low cost. But the daunting thought ahead for the Australian community is that water charges in excess of $2 per kilolitre will soon be with us. Such cost structures already exist in many parts of Europe.

A medium-sized sea-water desalination plant is now under construction in the Kwinana industrial area near Perth. It will have a capital cost of around $350 million and ...