This Device Pulls Water Out of Desert Air: A New Water Harvester Can Extract Water From Extremely Dry Air Using Only Solar Energy

Installing the water harvester (UC Berkeley)

by Emily Matchar, Smithsonian.com: 
https://www.smithsonianmag.com/innovation/this-device-pulls-water-out-of-desert-air-180969398/

Droughts have been making headlines across the world in recent years, from the California water crisis to Cape Town’s severe water shortage, and research suggests 25 percent of the globe could eventually be left in permanent drought due to climate change. But what if you could simply pull water from the air?

That’s the premise of a new technology developed by University of California, Berkeley researchers. It’s a water harvester that can extract water from the air, even in extremely dry climates, using no energy other than ambient sunlight.

The key to the water harvester is a new class of materials called metal-organic frameworks (MOFs). These MOFs are solid but porous materials with enormous surface areas—an MOF the size of sugar cube can have the internal surface area as big as many football fields. This means they can absorb gases and liquids, and then release them quickly when heat is added.

“Certain MOFs as we showed here have an extraordinary ability to suck in water vapor from the atmosphere, but then at the same time do not hold on to the water molecules inside their pores too tightly so that it is easy to get the water out,” says Omar Yaghi, a professor of chemistry at Berkeley, who led the research.

The researchers tested the harvester in Scottsdale, Arizona, a desert town with a high of 40 percent humidity at night and 8 percent humidity during the day. Based on the trials using a zironium-based MOF, the researchers believe that the harvester could ultimately extract about 3 ounces of water per pound of MOF per day.

The harvester itself is a box inside a box. The inner box contains a bed of MOFs. The outer box is a two-foot transparent plastic cube. At night, the researchers left the top off the outer box to let air flow past the MOFs. In the day, they put the top back on so the box would be heated by the sun. The heat would pull the water out of the MOFs, where it would condense on the inner walls of the plastic cube before dripping to the bottom, where it could be collected.

“The most important aspect of this technology is that it is completely energy-passive,” says Eugene Kapustin, a Berkeley graduate student who worked on the research.

That is to say, it needs no energy besides the sun, making it environmentally friendly and accessible to people in places with limited electricity. The results of the trials were published earlier this month in the journal Science Advances.

The team needs to conduct more trials on the current models to figure out which factors, such as device size and where the MOF is placed within the device, most affect how much water can be harvested. They also hope to learn more about how specific climate conditions affect water yield. The next trial is planned for late summer in Death Valley, where the nighttime humidity can be as low as 25 percent.

image: https://thumbs-prod.si-cdn.com/MQZyGQ7RZ_sZqpjHgdZsu9zGJyk=/1024x596/https://public-media.smithsonianmag.com/filer/1e/e9/1ee9eabf-f492-4102-a593-6fde846e9d41/mof303crystals750.jpg

Microscope image of crystals of an MOF (UC Berkeley)

Yaghi has also developed a new aluminum-based MOF he says is 150 times cheaper and can capture twice as much water as the current MOFs. He and his team are designing a new water harvester that actively pulls air into the MOFs at high speed, thus delivering a much larger volume of water.

The team is now partnering with industry to test harvesters on an industrial scale. They also continue to search for newer, better and cheaper MOFs.

“I am very happy to see that more and more researchers around the world are joining our efforts in this regard,” Yaghi says.

The idea of sucking water out of the atmosphere is not new, says Eric Hoek, an engineering professor at the University of California, Los Angeles and editor of the journal npj Clean Water. It’s long been noted that when you run an air conditioner, water drips out—this is because the machine is cooling the air to the dew point, the temperature at which the air is saturated with water vapor and condensation occurs.

But creating water harvesters based on cooling technology is incredibly energy intense. In very dry climates, the dew point is below zero. Cooling the air to that temperature at any large scale is unfeasible.

“The real innovation [of Yaghi’s research] is a materials innovation,” Hoek says. “These materials [the MOFs] pull water out and more easily give it up.”

But the concept is challenging to scale, Hoek cautions, as the amount of water produced per square inch of harvester is relatively low, and thus a large harvester would potentially take up a huge amount of land.

“But maybe for a household or village scale it could be a very interesting way for someone off the grid to get fresh water,” Hoek says.

Yaghi imagines exactly that: a future where everyone without easy access to fresh water has a harvester in their yard.

“My vision is to achieve ‘personalized water,’ where people in water stressed regions have a device at home running on ambient solar, delivering the water that satisfies the basic needs of the individuals,” he says. “More than one third of the population in the world lives in water-stressed regions or is suffering from lack of clean water. The potential implications of this technology in transforming people’s lives and improving the global public health conditions are tremendous.”



Read more: https://www.smithsonianmag.com/innovation/this-device-pulls-water-out-of-desert-air-180969398/#wcAVi3rVISdBXEqJ.99

This South Pacific Island of Rubbish Shows Why We Need to Quit Our Plastic Habit

Jennifer Lavers, University of Tasmania

A remote South Pacific island has the highest density of plastic debris reported anywhere on the planet, our new study has found.

Our study, published in the journal Proceedings of the National Academy of Sciences, estimated that more than 17 tonnes of plastic debris has washed up on Henderson Island, with more than 3,570 new pieces of litter arriving every day on one beach alone.

Our study probably actually underestimates the extent of plastic pollution on Henderson Island, as we were only able to sample pieces bigger than two millimetres down to a depth of 10 centimetres. We also could not sample along cliffs. Jennifer Lavers, Author provided

It is estimated that there are nearly 38 million pieces of plastic on the island, which is near the centre of the South Pacific Gyre ocean current.

Henderson Island, marked here by the red pin, is in the UK’s Pitcairn Islands territory and is more than 5,000 kilometres from the nearest major population centre. That shows plastic pollution ends up everywhere, even in the most remote parts of the world. Google Maps

A 2014 paper published in the journal PLOS One used data from surface water all over the world. The researchers estimated that there are 5.25 trillion pieces of plastic in the top 10 centimetres of the world’s oceans.

Plastics pose a major threat to seabirds and other animals, and most don’t ever break down – they just break up. Every piece of petrochemical-derived plastic ever made still exists on the planet.

Jennifer Lavers, Research Scientist, Institute for Marine and Antarctic Studies, University of Tasmania

This article was originally published on The Conversation. Read the original article.

Will Seattle Be the First U.S. City to Recycle Everything?

Truck dumps compost materials at process facility (E Thompson)

by Christine Woodside, Next City: http://nextcity.org/daily/entry/seattle-recycling-compost-sustainable-culture

It’s dawn on waste-collection day in the hilly Magnolia neighborhood of Seattle.

Along the curvy streets of this residential peninsula northwest of downtown, three large bins wait outside each house.

The green ones hold compost - leftover food and yard clippings. The blue ones overflow with everything recyclable: glass, plastic containers, cans and aluminum foil. The round black ones, for the trash, often aren’t full these days.

Three years ago, Seattle’s City Council passed Resolution 31312, calling for zero net emissions by 2050, one of few cities crusading for this goal; along with it came a concentrated effort to push residents to conserve water, drive less and recycle way more.

Half of Seattle’s greenhouse gas emissions are created through ordinary everyday life - getting around, eating and buying stuff. The city’s campaign used a gradual approach, phasing in rules like mandatory composting over three years, for example.

Seattle is one of a short list of American cities pushing for this level of effort by residents at home. Yes, early last century, some municipalities sent pigs around to eat garbage, but today, collecting food waste as a commodity is rare.

There’s Portland, Oregon, and San Francisco (the first American city to require compost collections, but most cities are still working on basic recycling of paper and containers.

Seattleites I talked to said they feel proud to save resources and that doing so feels like part of the city culture - despite what might be happening or not happening in other cities - dating back to the 1980s, when Seattleites were recycling brown and green glass ahead of most of the country.

“We’re a family of five, and our garbage is rarely full,” said Kelly Hufty, who lives with her husband, David Self, and their children in Magnolia. “But our recycling is stuffed and oftentimes the yard waste and composting is full.”

Resolution 31312 called for cutting greenhouse gas emissions to 58 percent below the 2008 levels by 2030 in three areas: transportation, commercial buildings and waste.

The latest report on greenhouse gas emissions from the city’s Department of Sustainability shows that those three key areas, in total, have remained the same - declined 0 percent - between 2008 and 2012, the most recent year evaluated.

However, the building and waste sectors have improved. The report shows that emissions generated by the collection of citizens’ refuse dropped 17 percent between 2008 and 2012. Building emissions are down 10 percent since 2008. Transportation emissions have increased by 6 percent since 2008 and by just 1 percent since 1990.

Sustainability officials admit that the progress looks slow, but they point out that the population has increased (by 23 percent since 1990). They say that if one considers emissions reductions on a per-person basis, the progress reflects the effort citizens have been making over the past few years. Per person, emissions have decreased by 6 percent since 2008 and 22 percent since 1990.

Although the city’s stated emissions goals, though, are total emissions, it’s hard to ignore the cooperation of the individuals as they deal with their own waste.

Back in 1980, the city reports, a family of three produced four 32-gallon cans of trash each week. Now that’s down to one or less than one. When the composting of food waste started three years ago, meat and dairy products were banned. Now the city takes those leftovers, too. All of the waste goes to a large composting operation run by a contractor.

The city’s statistics show that recycling is worth the trouble. One Seattle report notes that recycling had removed a net of 537,000 metric tons of carbon dioxide from the atmosphere in 2012 (in 1990, 439,000 metric tons were removed).

“It’s really great to be able to just roll that out to the curb, and away it goes - one bin - paper, plastic, metal,” says Herb Bergamini, a teacher who lives in Wallingford. He notes that the city will take labeled waste car oil too. Hufty, who used to live in the Washington, D.C. area, says, “It’s part of living out here.”

After all, this is the city where composting toilets were installed in a famous office building, the Bullitt Center, which was designed to be carbon neutral when fully occupied. The Bullitt Center collects rainwater and makes solar power.

When I visited, a staff member of Sustainable Seattle pointed me to the ladies’ room, where I could not trip the motion-sensor lights. But partly because of her attitude, I did not run back to ask for help. I fumbled for my headlamp.

Of course, even waste-savvy Seattle will not recycle many things that are part of modern American life: prescription pill bottles (the plastic is too brittle), wet or dirty produce bags, kitty litter, corks (the city does refer people to Whole Foods’ “cork reharvest” project), painted wood, treated wood, fats, cooking oils, grease.

But officials are working on changing these gaps in its program. Home cooking oil could join the other curb waste in the next five years, said Timothy Croll, the city’s solid waste director. He said a separate collection of kitty litter, pet waste and diapers could start “perhaps eight years from now.”

The city now faces the challenge of motivating residents to work even harder. Mayor Ed Murray announced this year in the city’s biennial environmental report, “Moving the Needle,” that he wanted to thank Seattle residents “for all that you will do” (emphasis mine) to reduce emissions.

The report soberly says that half of Seattle’s landfill-bound trash still is either food waste or recyclable. “We can do better!” the report noted.

One of the strategies of the sustainability department, which opened officially in 2000, is a poster crammed with other ideas: Don’t wash your blue jeans too often, eat less meat (sustainability officials say that meat-sellers have not complained about this), and, in this land of Microsoft, hold onto old laptop computer instead of buying new ones.

The department’s newsletter full of energy-saving tips motivates people, Hufty said. Her family doesn’t water their lawn at all now. And school programs on the new waste practices mean parents can’t get lazy. “If you try to put something in the garbage or down the disposal, you will get called on it,” Hufty said.

Still, the city’s ambitious goal will depend on the transportation piece, which accounts for 40 percent of the emissions, and while public transit funding has been in crisis, emissions from vehicles continues to rise. Building emissions have fallen, but population growth is expected to continue rising.

Can Seattle’s attitude make the difference? Geography that attracts nature lovers and the length of time Seattle has pushed for energy savings contribute to “our overall environmental savvy,” said Tracy Morgenstern, the lead advisor for climate change policy.

And as the city’s sustainability department communications advisor, Sara Wysocki, observes, “We have … a savvy population.”

Christine Woodside is a Connecticut-based writer and editor of the journal Appalachia. For more about her work, see chriswoodside.com.