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Admit it – we already drink recycled water

I heard someone ask recently: Has the same water been going around since the dinosaurs peed into it? Intriguing, especially when we think about it in the context of water reuse. Climate change is causing more extreme droughts and floods. As our growing population struggles for equitable allocation and access to limited freshwater resources, we are faced today with an urgent need to diversify our water portfolio.

Policy innovations for recycled water – The long view. Effective tackling of water security challenges demands policy innovations. We wholeheartedly endorse policies and technological innovations related to rainwater harvesting, fog catching or decentralized solar-enabled water purification systems (e.g., the Watercone). But using recycled water seems yucky, and efforts to encourage the use of recycled water have received some strong pushback in the past.

The recent droughts in California, however, have resuscitated the discussions about water recycling in the United States. But how successfully do water recycling policies survive the ebbs and flows of environmental stresses, political will, and public memory? Dr. John C. Radcliffe’s recent article gives new insight into this question. The article outlines the successes and shortcomings of Australia’s water recycling over the last two decades, when the prolonged “Millennium Drought” in the 2000s made it necessary for Australia to adopt alternative strategies for water security, and to develop new policies for potable uses of recycled water. Things looked promising for Australia’s long-term water sustainability… but then the droughts ended.

Complacency + the Yuck factor = Terrible, no-good, very bad self-inflicted water crisis. Our resolve to address water sustainability issues and to implement long-term solutions is often tested – ironically – when the threat of water scarcity temporarily fades. As Radcliffe notes, “The end of the drought in eastern Australia has distanced community, industry and government policy focus from strengthening the security of water supply (at almost any cost) to one of pursuing economic efficiency and containing consumers’ water charges and prices.” And the Yuck factor about toilet-to-tap policies doesn’t help.

Blue Gold slipping through our fingers. The poignant opening lines of an Urdu ghazal from yesteryears croon: Duniya jise kehte hain / jaadoo ka khilona hai / Mil jae toh mitti hai / kho jae toh sona hai. Meaning: This world is magical. Here, when we are fortunate to have something, we treat it like dirt (mitti). But as it begins to slip away, it becomes precious like gold (sona). Opportunities to successfully meet our water challenges are shrinking. That glass of water sitting on the toilet seat on the right has been rightly called Blue Gold. And it is slipping away.

Today, while reassessing our water policies while threats to our water security loom in the horizon, let us not forget the lessons that hindsight has to offer.

You can access the full paper for free* using the link below:

Water recycling in Australia – during and after the drought
John C. Radcliffe
Environ. Sci.: Water Res. Technol., 2015,1, 554-562
DOI: 10.1039/C5EW00048C




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About the webwriter

Paramjeet Pati is a PhD Candidate at the Virginia Tech Center for Sustainable Nanotechnology (@VTSuN).
You can find more articles by him in the VTSuN blog, where he writes using the name coffeemug.

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*Access is free through a registered RSC account – click here to register

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Purity and character of water

The purity of water can mean different things to different people. When I call a glass of water pure, am I saying that it’s safe to drink, or clean enough to be labeled as “research-grade”, or do I mean that it has two molecules of hydrogen for every molecule of oxygen and absolutely nothing else? And where can we find the purest, cleanest water in nature?

Pure as the driven snow?

Image adapted from Wikipedia

It ain’t pure if it’s natural. It ain’t natural if it’s pure. As rain and snow make their way to the earth, they dissolve particles, minerals and gases. Once on the ground as surface water from rain and snowmelt, the water continues to gather dissolved and suspended materials (including microorganisms), as it flows over the soil and the rocks. Rainwater and snow also contain many pollutants and may not be appropriate for drinking without treatment. So, the next time someone tries to sell you a bottle of “pure natural water”, ask where that pure water came from, because, as Machell et al. say in a recent paper, “Pure water does not exist in nature…”.

If it ain’t pure, is it safe? Indeed this is a key question that links drinking water with public health issues. Very few drinking water quality parameters require legal compliance. The Drinking Water Directive in Europe and the Safe Drinking Water Act in the United States are notable exceptions. But most drinking water quality parameters serve merely as guidelines, rather than specific requirements that can be enforced by law.

Due to increasing stresses on our water infrastructure, we are now forced to look for alternative sources of water (such as wastewater reuse, rainwater harvesting and dual distribution systems for potable and non-potable uses).  So, a clear understanding of purity becomes even more important when these alternative sources are used to provide fit-for-purpose or safe-to-drink water.

Ultrapure water - not good for making tasty ice

Image adapted from Wikipedia

“If I find the world’s cleanest, purest water, I can make the world’s tastiest ice.”, said David Rees in an episode of Going Deep (National Geographic).  But he was disappointed after tasting ultrapure water – i.e., water devoid of any impurity. (Perhaps he was also disappointed that he was not allowed do a keg stand, and had to drink the water from a flask.)

In fact, ultrapure water is quite expensive and is an aggressive solvent used semiconductor industry for cleaning wafers – definitely not meant for making the world’s tastiest ice. Rees succinctly summed up the issue: “Don’t overpurify your water – minerals and salts add character.”

An old saying goes: “Water which is too pure has no fish.” Today, we need a more nuanced understanding about water purity to assess the tradeoffs between the cost of treating water and acceptable levels treatment for providing safe drinking water. Indeed, as Machell et al. say, “Water purity is a vague term… Safe water is economical and attainable, whereas pure water is not.”


How does this idea of water purity govern environmental monitoring and risk assessment? Find out by reading the full paper for free* using the link below:

Drinking water purity – a UK perspective
John Machell, Kevin Prior, Richard Allan and John M. Andresen
Environ. Sci.: Water Res. Technol., 2015,1, 268-271
DOI: 10.1039/C5EW90006A, Forum

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About the webwriter

Paramjeet Pati is a PhD Candidate at the Virginia Tech Center for Sustainable Nanotechnology (@VTSuN).
You can find more articles by him in the VTSuN blog, where he writes using the name
coffeemug.

————

*Access is free through a registered RSC account.

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