drinking water

Using CO2 To Convert Seawater Into Drinking Water | Earth Wise

October 27, 2020 By EarthWise Leave a Comment

A chemist at the University of Copenhagen has invented a technology that uses carbon dioxide to convert seawater into drinking water within minutes. This desalination technology has the potential to replace electricity with CO2 and be used in survival gear and in large-scale industrial plants in places where people don’t have clean drinking water.

Over 800 million people worldwide lack access to clean drinking water and that number is growing rapidly. Seawater is a vital source of drinking water in many parts of the world, but desalination faces the major challenge of being highly energy intensive. Desalination plants use huge amounts of fossil fuel-generated electricity and therefore contribute to climate change.

The Copenhagen technology is reminiscent of a SodaStream machine. Carbon dioxide is added to water, initiating a chemical reaction. But instead of using it for bubbly carbonation, it is used to separate salt from water. It works by adding a chemical called CO2-responsive diamine to saltwater. The diamine compound binds with the added CO2 and acts as a sponge to absorb the salt, which can then be separated. The entire process takes one to ten minutes. Once the CO2 is removed, the salt is released again, allowing the diamine to be reused for several more rounds of desalination.

In the laboratory, the method removed 99.6% of the salt in seawater. The technology is still being developed to lower its price and optimize the recycling process. It is also being tested on a small scale in the form of water bottles fitted with special filters that can be used in lifeboats or in other outdoor settings. Ultimately, it could be used to greatly reduce the energy consumption of desalination plants.

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Chemist uses CO2 to convert seawater into drinking water

Photo, posted January 10, 2015, courtesy of Daniel Orth via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Which Cities To Save From The Changing Climate

October 28, 2019 By EarthWise Leave a Comment

After several years of brutal flooding and hurricanes in the U.S., a distressing debate is emerging: if there is not enough money available to protect every coastal community from the effects of global warming, how do we decide which ones to save first.

Recent research looked at the costs involved in providing basic storm-surge protection in the form of sea walls for all coastal cities with more than 25,000 residents. That number was $42 billion. Expanding the list to include communities smaller than 25,000 people would increase that cost to more than $400 billion. Realistically, that is just not going to happen.

This particular study only looked at sea walls and no other methods for minimizing flood risk, such as moving homes and businesses away from the most flood-prone areas. It also didn’t look at additional and costlier actions that will be required even with sea walls, such as revamping sewers, storm water, and drinking water infrastructure.

The facts are that many cities, especially small ones, will not be able to meet the costs facing them. Those that can’t will depend on federal funding. But even optimistically large proposals for federal infrastructure spending are likely to fall far short of the vast need. Ultimately, the money will end up being spent where it can do the most good – even if it means that some places are left out.

But what criteria will be used to direct the money? Economic value? Historic significance? Population? Political influence?

This is a looming and massive issue whose chief obstacle may be that many officials refuse to acknowledge that it is happening. This is the next wave of climate denial – denying the costs that we are all facing.

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With More Storms and Rising Seas, Which U.S. Cities Should Be Saved First?

Photo, posted October 31, 2018, courtesy of Patrick Kinney via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar-Powered Desalination

October 4, 2019 By EarthWise Leave a Comment

Turning seawater into drinking water is an energy-intensive process and is therefore pretty expensive. Worldwide, one third of people don’t have reliable access to safe drinking water and they are the least able to afford expensive ways to get it. By 2025, half of the world’s population is expected to live in water-stressed areas.

At a newly-constructed facility in Kenya, a nonprofit company called GivePower has built a desalination system that runs on solar power. The system started operating in the coastal area of Kiunga in July 2018 and can create nearly 20,000 gallons of fresh drinking water each day – enough for 25,000 people.

GivePower started in 2013 as a nonprofit branch of SolarCity, the solar-panel company that ultimately merged with Tesla in 2016. However, GivePower spun off as a separate enterprise shortly before that.

GivePower mostly focuses on building solar-energy systems to provide electricity across the developing world.

Desalination technology is not new, but it is notoriously energy-intensive because it requires high-power pumps. The GivePower system is integrated with a solar microgrid that makes use of Tesla batteries to store energy for when the sun is not shining.

Local residents pay about a quarter of one cent for every quart of water from the system. The Kiunga community has faced ongoing drought and before the GivePower system was installed, was forced to drink from salt water wells, which present serious health risks.

The GivePower system cost $500,000 to build and is expected to generate $100,000 a year, to be eventually used to fund similar facilities in other places.

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A solar-powered system can turn salt water into fresh drinking water for 25,000 people per day. It could help address the world’s looming water crisis.

Photo courtesy of GivePower.

Earth Wise is a production of WAMC Northeast Public Radio.

Heat And Plastic Bottles

August 21, 2019 By EarthWise Leave a Comment

In the middle of July, Americans along the East Coast and in the Midwest suffered through a massive heat wave that saw actual temperatures soaring and so-called feels-like temperatures go much higher. The punishing heat had many of us reaching for those plastic water bottles all day long as we tried to keep hydrated.

Studies have shown that those single-use plastic bottles do not handle the heat very well. Most plastic items release tiny amounts of chemicals into the beverages or food that they contain. But the hotter it gets, the more the substances in plastic can move into food or drinking water. As temperature and time increase, the chemical bonds in plastics increasingly break down and chemicals are more likely to leach.

A study at Arizona State University in 2008 looked at how heat sped up the release of the element antimony in bottles made of the common plastic PET. Antimony is used to manufacture the plastic and can be toxic in high doses. At mild temperatures, very little antimony is released. But PET and other plastics can leach a variety of chemicals when exposed to higher temperatures.

According to the FDA, the amounts of chemicals released by plastics are too miniscule to cause health problems. However, scientists are still looking at the long-term effects of using so much plastic. The question is whether all those small doses can eventually add up to something not so harmless. Given that we don’t really know the cumulative effect of being surrounded by plastics in the goods we buy as well as the presence of microplastics in our water, it seems like a good idea to try to limit our exposure when alternatives are available.

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Exposed to extreme heat, plastic bottles may ultimately become unsafe

Photo, posted June 7, 2013, courtesy of Tim Stahmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protection From Toxic Algae

March 28, 2019 By EarthWise Leave a Comment

Toxic algal blooms have been a growing problem in recent years associated with warming waters and nutrient-rich agricultural runoff in lakes, rivers, and oceans. In 2014, an algal bloom in Lake Erie left half a million residents of Toledo, Ohio without safe drinking water for three days.

The most common toxic substance released by algal blooms in the lake is called microcystin, which is closely linked to liver cancer and other diseases. Toxicologists measure microcystin and other contaminants using the metric of parts per billion. The EPA recommends that young children not drink water containing more than 0.3 parts per billion and adults no more than 1.6 parts per billion of microcystin.

Scientists at the University of Toledo have been working on developing a biofilter that uses naturally occurring Lake Erie bacteria to remove microcystin released by algal blooms and thereby reduce or eliminate the use of chlorine and other chemicals.

They have successfully isolated a number of types of bacteria that degrade microcystin toxin at a daily rate of up to 19 parts per billion. To their knowledge, such bacteria have not been previously used to fight algal blooms in other parts of the world. Based on the recorded toxin levels in Lake Erie in recent years, the bacteria would be able to effectively remove microcystin from water supplies. None of the 13 bacterial isolates they found have any association with human disease so their use in future water-purifying biofilters should not pose a public health concern.

The researchers are now developing and testing biofilters, which are water filters containing the specialized bacteria that will degrade the toxins from lake water as it flows through the filter.

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Scientists advance new technology to protect drinking water from Lake Erie algal toxins

Photo, posted April 30, 2014, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Glaciers And Water Supply

March 25, 2019 By EarthWise Leave a Comment

The world has roughly 150,000 glaciers covering about 200,000 square miles of the earth’s surface. Over the last 40 years they’ve lost the equivalent of a layer of ice 70 feet thick. Most of them are getting shorter as well. Some have shrunk to nothing; many smaller glaciers in places like the Rockies and the Andes have disappeared entirely.

Glaciers represent the snows of centuries, compressed over time to form flowing rivers of ice. They always change over time, accumulating snow in winter and losing ice to melting in summer. But in recent times, the warming climate has allowed the melting to outpace the accumulation.

Much of the discussion about the retreating glaciers relates to sea level rise, catastrophic floods, debris flow, and the effects on rivers and ecosystems.

But in some places, the biggest impact of the loss of glaciers is on the supply of water for people and agriculture. In Kazakhstan, Almaty, the country’s largest city depends on glacier-fed rivers for drinking water for its 2 million people and for irrigation water for crops. All across the Tibetan Plateau and the Himalayan and Karakmoram mountain ranges, hundreds of millions of people rely on glacier-fed rivers for their water supplies.

A melting glacier can at first increase stream flow but eventually reaches a tipping point and meltwater begins to taper. In the short term, the melting glaciers may provide increased amounts of water coming down from the mountains, but eventually the flow in the rivers will begin to decline and populations will face a crisis.

It will be essential for people in many places to carefully plan for their future water needs in a changing world.

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Glaciers Are Retreating. Millions Rely on Their Water.

Photo, posted September 16, 2011, courtesy of 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.

Wildfires And The Water Supply

November 12, 2018 By EarthWise Leave a Comment

Hotter and dryer conditions are leading to an increasing number of wildfires in North America and elsewhere around the world. The damage they cause is well-known. But one aspect of that damage that tends to be overlooked is the impact on aquatic environments and drinking water supplies.

Clean Water In The Corn Belt

October 26, 2018 By EarthWise Leave a Comment

Iowa is grappling with a growing battle over the integrity of its water. Nitrogen and phosphates have been flowing in ever-increasing quantities into Iowa’s public water supplies and dealing with the problem has become a major political issue in the state.

Salt Cocktails Compromise Freshwater

August 1, 2018 By EarthWise Leave a Comment

Human activities are exposing US rivers and streams to a cocktail of salts, with consequences for infrastructure and drinking water supplies. Road salt, fertilizers, and mining waste – as well as natural weathering of concrete, rocks, and soils – all contribute to increased salt in waterways. When these different salt compounds combine, their harmful effects can amplify.

Fresh Water From Power Plants

July 24, 2018 By EarthWise Leave a Comment

A new system developed by MIT engineers could provide a low-cost source of drinking water and simultaneously reduce power plant operating costs.

Wastewater Instead Of Dams

July 2, 2018 By EarthWise Leave a Comment

The era of dam building is coming to an end in much of the developed world. Dams are very expensive, environmentally harmful, and as the climate warms and droughts become more common, are not that reliable.

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.

Fracking And Streams

March 8, 2018 By EarthWise Leave a Comment

Hydraulic fracturing – better known as fracking – is a method of extracting oil and gas from shale deposits in which millions of gallons of freshwater and chemicals are injected into deep underground deposits. There has been a great deal of concern related to the effects that this process has on water quality and also on the stability of the ground in the vicinity of where it takes place.

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Small Grains In Corn Country

January 31, 2018 By EarthWise Leave a Comment

Large portions of the Midwest are called the Corn Belt and for good reason. Overall, about 90 million acres or 140,000 square miles of the United States are planted with corn and about half of that is in Iowa, Illinois, Nebraska and Minnesota. In most of the Corn Belt, the corn is planted in rotation with soybeans. Both are warm weather crops and the soil is left barren for nearly half of the year when the two crops are out of season.

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.

Nature Is Satisfying

May 16, 2017 By EarthWise

For most of us, a day spent in the mountains, the woods, or at the beach always seems like a good day. Communing with nature tends to make us feel better.

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Coal And Water

April 19, 2016 By WAMC WEB

We recently highlighted how safe drinking water is in short supply. According to research published in the journal Science Advances, at least two thirds of the global population – more than four billion people – live with severe water scarcity for at least one month every year. And 500 million people around the world face water scarcity all year.

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Road Salt

January 19, 2016 By WAMC WEB

Snow season is here. The chances are good you’ll find yourself behind a truck spreading salt on the roads in an attempt to deice them. You may even try a little salt on your own front porch. Annually we spread about 20 million tons of road salt in the U.S., and we’ve been doing it since the late 1930s.

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Snowpack Loss

December 2, 2015 By WAMC WEB

A recent study showed that this year the snowpack in California, which is suffering an ongoing drought as well as long-term warming, reached its lowest point in 500 years. Snowmelt from the Sierra Nevada mountains fills reservoirs that provide a third of all of the drinking water for the state of California, as well as water used to fight fires and generate electricity.

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