Wednesday, July 02, 2014

Recycling Water Crucial To NT Water Supplies

In the face of global water supply shortages, recycled water has the potential to help us be more climate-independent. And even though it seems novel, reused water is already cycled back into the supply. If you live in a community downstream of another one, chances are, you are reusing its water.
Australians and Americans have embraced “sustainability” in so many aspects of modern life, but not when it comes to water resources.

Recycled or reclaimed water is water that is used more than one time before it passes back into the natural water cycle. Treated wastewater, including sewage and water used for industrial processing, can be cleanly recycled for agricultural and landscape irrigation, industrial processes, toilet flushing, replenishing a groundwater basin and even for drinking water.

Scientifically proven advances in water technology — including reverse osmosis, ultraviolet disinfection, and oxidation — applied to wastewater allow communities to reuse water for many different purposes, treating the water differently depending on the intended use.

And the best part is: there is huge potential for growth in using recycled water. Thirty-two billion gallons of municipal wastewater are produced everyday in the United States but less than 10 percent of that is intentionally reused and the equation is quite similar in the Northern Territory, particularly in the northern areas, as Alice Springs now does have an aquifer recharge program using treated wastewater from the effluent ponds.  

Also, it is known that the NT uses up to four times water per person more than temperate Australia, and much of that extra water is used outside, where non potable water would do.  It is certainly wasteful to treat all water to drinking standards and then use 70% outside as is common in Darwin.

One key reason that water reuse is not a bigger part of the nation’s water supply is that it is still characterized as a waste product in most places. 

In a progressive move, California in the US recently enacted legislation that reclassifies recycled water as a water resource. The state government also recently streamlined the permitting process for using recycled water for irrigation and allocated $200 million in grants to encourage related projects.  While California uses different legislative systems to Australia, the truth is, Australia could do a lot ore with use of appropriately treated wastewater.  AND......such programs would be sensible infrastructure development in a continent as dry as ours.

In other parts of the USA,communities in dry west Texas have used state-of-the-art technology to augment their drinking water supply with reused water; Phoenix in Arizona has had an aquifer recharge program using treated effluent which is subsequently redrawn for use, for about 50 years; the governor of Oklahoma just signed a law to encourage water reuse; and Florida’s most recent water reuse report indicated that 719 million gallons of water is beneficially reused each day in 2013 — the largest amount in the country.  Yet here in north Australia as we discuss developing the north, there is little discussion about reuse of water, in an environment which is totally dry for 6-8 months each year, while in the other few months water flows away freely [ admittedly it is used by the environment!].

The amount of water intentionally reused in both Australia and the USA still quite low and it will stay that way as long as the public regards reuse as an emergency measure. Citizens have embraced “sustainability” in so many aspects of modern life, but not when it comes to water resources.

Conservation cannot meet future water demands alone and other measures that create new sources of water, like desalination, are still more expensive, with some people believing that it is too expensive although newer technologies are encouraging in possibly lower costs.  Desalination has its advocates though, with WA a champion of the technology, with development being driven by the woman who is the Chair of the WA Water Corporation.

In the Top End of the NT the only avenue seemingly being explored for more water is to develop more dams or other above ground storage systems, such as the pumped off river system discussed for an area in hills north of Adelaide River, and the dam above Adelaide River.  Desalination of seawater is also a possible option around Darwin. 

Water reuse is the easiest and most economical fix. It should be included in the water supply portfolio of the Darwin region, and in fact for all  communities.  It at least should be given equal weight in assessing future water resources for the region.

[ partially adapted from an article by Melissa Melker of the US Water Reuse Association in the NY Times 30 June 2014]
This is a solar technology to distill irrigation tailwater from agriculture fields using solar technology to heat a oil filled tube and then use the heat to distill the tailwater.  It works and can be scaled up, with a projected cost of about one quarter the cost of desalination of sea water [ many places say a cost for this of $2 per kilolitre].  Search for Water FX online for more details.

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