Re-Engineering the Water Cycle

May 21, 2015

Controlling the water cycle is a serious engineering problem. 

This is the first article in a series on water crises and solutions. Part II focuses on the drought in California, Part III explores challenges related to rising sea levels in Florida.

It’s not that there’s not enough water; after all, 71% of the planet’s surface is covered in the stuff. All told, we have over 300 million cubic miles of it – that’s 3.63368659 × 10^20 US gallons.

It’s that it’s in the wrong places – at least as far as humans are concerned.

It’s a potential catastrophe for many millions of people, who stand to lose their homes, their livelihoods, or worse. While California and Washington are suffering from unprecedented drought, some island nations could be submerged completely.

This isn’t the place to argue about the causes of the disruption to our water supply, let alone the political rights and wrongs of the issue. As engineers, our task is to understand the problem and find solutions.

The Problem with the Water Cycle

The disruption of the water cycle creates clear and present dangers to human life.

Some parts of the world are suffering from massive drought, jeopardizing some of the most agriculturally productive regions of the planet and increasing the risk of wildfires. Other places are threatened by rising sea levels, destroying sea-front properties, contaminating lowland areas and tainting the aquifers which supply the water for our crops and our drinking water. The UN predicts that by 2030 there will be a 40% shortfall in drinking water across the world.

When people don’t have enough to drink, ‘civilized’ conduct is not a priority. History warns us to expect war, death on a massive scale, waves of refugees.

Credit: James Marvin Phelps

Credit: James Marvin Phelps

It’s all too easy to dismiss this as alarmist nonsense, but climate scientists, hydrological engineers, agricultural engineers, geologists and social scientists are already warning that we are rapidly approaching a tipping point if we don’t learn to reduce our water use, conserve what we have, and address the problem.

Until recently, politicians have been extremely reluctant to get involved, particularly in the US. Mandating water conservation isn’t a vote-winner. People want to continue watering their lawns, washing their cars, and drinking bottled water, and don’t want the government telling them they can’t, or making them pay extra for it. Businesses and farmers don’t want to invest in new, more efficient equipment. And, unsurprisingly, utility companies want to continue business as usual. Although, as we’ve recently seen in California, some politicians are prepared to implement short-term emergency measures, that confrontational approach is unlikely to be effective in the long term.

Long-term answers lie in the hands of engineers. Their role will be to develop technologies that reduce our water usage, increase the availability of drinking and agricultural water, hold back the rising seas, and ultimately, attempt to reverse the effects on our climate.

On the grand scale, this amounts to nothing less than planetary engineering: creating space mirrors or solar shields made of reflective aerosols to reduce the heat reaching the atmosphere: fertilizing the seas with iron; creating new crop varieties that use less water and are more salt-tolerant; or even genetically engineering human beings to consume less food. Many of these ideas seem far-fetched, and straight out of science fiction, but engineers are taking them seriously.

Small Solutions Scale

Credit: Evan Leeson

Credit: Evan Leeson

While these massive technologies could be effective in the long term, they’re huge, risky projects that could take decades to come to fruition if they ever work. We need answers now.  There are thousands of smaller approaches that will make an immediate difference. That’s where the real impact is going to be. To misquote a famous misquote, a billion gallons here, a billion gallons there, and sooner or later, it all adds up.

Sometimes, this involves getting seriously down and dirty with the problem.

Jeremy Irons is a Design Engineer at Creative Engineering in Bronxville, New York, who’s acutely aware of what needs to be done. He’s proudly showing off one of his most recent projects, the Tap-n-Flush toilet converter, which has the potential to save hundreds of billions of gallons of water a year. Reducing the water used to flush toilets is nothing new: while older toilets can use anything up to 7 gallons per flush (gpf), newer ones are required by federal law to use no more than 1.6gpf. Just to put that into perspective, in the US, we typically use around 3 to 4 billion gallons a day, just flushing the toilet. That’s over a trillion gallons a year – and nearly all of it is valuable drinking water that goes straight back down the sewer pipe. Reducing that usage by even 10% would have a huge impact on our consumption. The old adage, “if it’s mellow, let it yellow, if it’s brown, flush it down,” has some merit, but these days, we don’t generally want to live with the odor.

That’s where dual-flush toilets come in. 80% of the time, just one gallon of water will do the job. For those other occasions, a little more is called for, usually around 2gpf. That’s why sometimes you need to flush twice, which means you’re actually using far more water than necessary if you have a 1.6gpf toilet. Being able to select the right amount of flush means you can reduce your water usage by up to 38%, even if you already have a low-flow toilet.

That’s great if you have a new home or you’re remodelling your bathroom anyway, but there’s still a big problem. Dual-flush toilets typically cost anything from $300 to $1000, plus an additional $100 for installation. That may not sound like a lot, but for most of the population, already struggling in a recession, that’s not an affordable expense, especially since it probably only saves less than $100 a year. For renters, there’s no incentive to invest in a home they don’t own, while for landlords, there’s no incentive to spend money to reduce their tenants’ water bills. As a result, most of us still use old, inefficient toilets.

The Tap-n-Flush, created by Hawaiian inventor Jeff Nasrullah, aims to address this problem. It’s a simple adaptor that can be attached to any existing toilet and converts it to a dual-flush system for less than $40. Better still, since there’s no universal perfect setting for the ideal flush, it can be tuned to the needs of individual toilets and families, depending on the construction of the toilet bowl, sewer pipe, and preferred diet.

“It’s not the most glamorous job in the engineering world, but these are the kind of products that have the potential to have a huge effect on the way we live,” says Irons. “It’s no exaggeration to say that every one of us will be affected in some way.”

Credit: Les Haines

Credit: Les Haines


Part II of this series explores engineering responses to the drought in California, Part III challenges related to rising sea levels in Florida.



Featured Image Credit: Jeff Wallace
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