drinking

Harvesting Fresh Water From Ocean Air | Earth Wise

January 19, 2023 By EarthWise Leave a Comment

Roughly three-quarters of the world population has access to a safely managed water source. That means that one-in-four people do not have access to safe drinking water. Even in the wealthy United States, persistent drought in the west is creating problems in places like Phoenix, Arizona.

Water is plentiful on Earth but more than 99% of it is unusable by humans and many other living things because it is saline, frozen, or inaccessible. Only about 0.3% of our fresh water is found in the surface water of lakes, rivers, and swamps.

There is an almost limitless supply of fresh water in the form of water vapor above the oceans, but this source is untapped. Researchers at the University of Illinois have been evaluating the feasibility of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water.

Existing ways to obtain fresh water like wastewater recycling, cloud seeding, and desalination have met only limited success and present various problems with regard to cost, environmental impact, and scalability.

The researchers have proposed hypothetical large offshore structures measuring 700 feet by 300 feet to capture water vapor that is continually evaporating from the ocean in subtropical regions. Their modeling concluded that such structures could provide fresh water for large population centers in the subtropics. Furthermore, climate projections show that the amount of water vapor over the oceans will only increase over time, providing even more fresh water supply.

This is only a theoretical study at this point, but the researchers believe it opens the door for novel infrastructure investments that could address global water scarcity.

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Researchers propose new structures to harvest untapped source of fresh water

Photo, posted June 28, 2009, courtesy of Nicolas Raymond via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving Water At Power Plants | Earth Wise

September 21, 2021 By EarthWise Leave a Comment

Nearly 40% of all the water taken from lakes, rivers, and wells in the U.S. isn’t used for agriculture, drinking, or sanitation. It is used to cool power plants that produce electricity by burning fossil fuels or with nuclear reactors. Two-thirds of these power plants use evaporative cooling, which produces huge white plumes billowing from cooling towers.

A new company using technology developed at MIT has the goal of reducing the water needs of power plants and helping to alleviate water shortages in areas where power plants strain the capacity of local water systems.

The technology is relatively simple in principle but developing it to the point where it can be applied at full scale at industrial power plants was a greater challenge.

The basic idea is to capture water droplets from both natural fog and from the plumes from power plant cooling towers. The MIT researchers had to improve the efficiency of fog-harvesting systems, which previously captured only 1-3% of the water droplets that pass through them. They found that water vapor collection could be made much more efficient by zapping the tiny droplets of water with an ion beam, giving them a slight electric charge, thereby making it easy to capture them with the metal mesh of the harvesting system.

The system can essentially eliminate cooling tower plumes and produce large quantities of high-purity water in the process, which has uses at many power plants. The new company, called Infinite Cooling, has arranged to install their equipment on two operating commercial power plants later this year. They expect the system to reduce the overall need for water by 20%.

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Vapor-collection technology saves water while clearing the air

Photo, posted March 5, 2019, courtesy of Sam LaRussa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Global Assessment Of Groundwater Wells | Earth Wise

May 19, 2021 By EarthWise Leave a Comment

Water is a fundamental need for every human being on the planet. Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean.

Groundwater wells remain one of the primary sources of drinking water. In fact, more than half of the world’s population gets its drinking water from groundwater wells. Groundwater wells also sustain more than 40% of irrigated agriculture.

Researchers from UC Santa Barbara have recently compiled the most comprehensive assessment of groundwater wells to date. Their research, which was recently published in the journal Science, spanned 40 countries, which collectively account for more than 50% of all groundwater pumping.

According to the survey’s findings, many wells are at risk of running dry – up to one in five wells, to be exact. The researchers compared the depths of water tables against well depths. They found that 6% to 20% of the wells in the study were at risk of running dry if water levels continue to decline by just a few meters.

In many areas where groundwater levels are declining, the research team found that new wells are not being drilled deeper to keep pace with the falling water table. As a result, newer wells are just as vulnerable as older wells should groundwater levels continue to decline.

The researchers hope to expand on this study to include data from China, Iran, and Pakistan, three major users of groundwater from which the researchers could not obtain records. The researchers also plan to investigate how quickly water tables are dropping and where the trend is accelerating.

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The largest assessment of global groundwater wells finds many are at risk of drying up

Photo, posted January 20, 2018, courtesy of François Molle via Water Alternatives Photos on Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Pulling Water From The Air

October 14, 2019 By EarthWise Leave a Comment

A couple of years ago, we reported on the early development of a device that harvests water from the air that even works in the low humidity environment of a desert. Since then, the researchers from UC Berkeley have continued to improve the device and it is now 10 times better than it was two years ago.

The harvester is based on a porous water-absorbing material called a metal-organic framework, or MOF. The latest version can pull more than five cups of water from low-humidity air per day for every kilogram of the improved MOF material and that is more than enough water to sustain a person. The harvester cycles around the clock and is powered by solar panels and a battery.

Previous techniques for condensing water from air at low humidity required cooling down the air to temperatures below freezing, which is not economically practical. The MOF-based device does not require any cooling.

The Berkeley researchers have formed a startup company – Water Harvester, Inc. – which is now testing and will soon market a device the size of a microwave oven that can supply 7 to 10 liters of water per day, which is enough drinking and cooking water for two or three adults.

An even larger version of the harvester, which would be the size of a small refrigerator, would provide 200 to 250 liters of water per day, enough for a household to drink, cook, and shower. The new company envisions a village-scale harvester that would produce 20,000 liters per day, still running off of solar panels and a battery.

Water Harvester believes the water needs for many people can come out of the thin air.

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Water harvester makes it easy to quench your thirst in the desert

Photo courtesy of Grant Glover (University of South Alabama) via UC Berkeley.

Earth Wise is a production of WAMC Northeast Public Radio.

Trouble On The Colorado

April 4, 2019 By EarthWise Leave a Comment

The 1450-mile-long Colorado River begins in the Rocky Mountains and wends its way to the Gulf of California, creating the Grand Canyon along the way, and providing water to some 40 million people. The amount of Colorado River water promised to users is far more than actually flows between its banks, and that amount is dropping.

An unrelenting drought since 2000 has resulted in the water levels of the two largest reservoirs of Colorado River water – Lake Mead and Lake Powell – being at all-time lows.

Lake Mead, just outside of Las Vegas, is the reservoir of Hoover Dam, which provides power for millions of people in Southern California, Nevada, and Arizona. The last time Lake Mead was full was in 1983. It has slowly declined and now is 40% full.

If the lake level drops another 7 feet to 1075 feet above sea level, it will trigger a Tier 1 declaration, mandating cuts to water allocations to Arizona and other states. If the level drops to 1050 feet, it would reach Tier 2 at which point Hoover Dam would have to stop generating electricity because water levels would be too low to flow through it. If the lake level drops all the way to 895 feet, it would be below the level at which water can be piped out of it. This is known as the “dead pool”.

These scenarios are no longer doomsday fantasies. Water managers in the Southwest see the writing on the wall and are busy making contingency plans and developing ways to use less water from the Colorado River. The booming city of Phoenix in particular is hard at work finding alternative ways to provide water for its millions of citizens. On the Colorado, drought in the new normal.

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On the Water-Starved Colorado River, Drought Is the New Normal

Photo, posted October 24, 2016, courtesy of Sharon Mollerus via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Better Filter For Saltwater

November 26, 2018 By EarthWise Leave a Comment

Turning seawater into drinkable water is a highly desirable capability given that fresh water is generally in short supply and seawater is endlessly abundant. Desalination plants typically strain salt out of seawater by pumping it through films made of polyamide. Polyamide filters are riddled with tiny pores that allow water molecules to squeeze through, but not sodium ions.

Are We Drinking Plastic?

April 26, 2018 By EarthWise Leave a Comment

Almost everyone everywhere comes into contact with plastic everyday. Its use has increased 20-fold in the past half-century, and production is expected to double again in the next 20 years. But is plastic so ubiquitous that we are unwittingly drinking the stuff?

How Safe Is Drinking Water?

March 26, 2018 By EarthWise Leave a Comment

Water is life. It’s a fundamental need for every human being on the planet. Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean. Dirty water, on the other hand, can be deadly. An estimated 1.8 million people die every year as a result of diarrheal diseases like cholera. And tens of millions of people are seriously sickened by water-related maladies.

Dioxane And Drinking Water

October 24, 2017 By EarthWise Leave a Comment

A byproduct of plastics production, dioxane is a clear, synthetic, liquid solvent that easily mixes with water. It’s frequently used in paint strippers, dyes, and varnishes, as well as shampoos and body washes – particularly those that are sudsy. Dioxane doesn’t really biodegrade and is widely regarded as a contaminant.

Turning Seawater Into Drinking Water

May 10, 2017 By EarthWise

Graphene is often called the wonder material. First isolated by scientists in 2004, it is a form of carbon that is just one atom thick, extremely light, two hundred times stronger than steel, highly flexible, and an excellent conductor of heat and electricity. Scientists are finding numerous applications for it.