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Wasting less wastewater

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Ultra-pure water is essential for multiple industries, for example semiconductors, batteries, and pharmaceuticals, as well as food and beverage companies.  Such water is produced by various processes including desalination plants that use reverse osmosis.  The byproduct of the processing is industrial brine:  salty wastewater.

The brine produced by desalination is generally dumped into the ocean if the desalination plant is located at the seashore, but if the plant is inland, such as in places like Arizona, that isn’t an option.

Nestle runs a water desalinating plant near Phoenix that generates more than 50,000 gallons of brine every day.  Concentrated brines must be carefully managed and disposed of. 

Researchers at Arizona State University are developing a mobile, closed-loop water recovery demonstration system that aims to recover 50%-90% of previously unusable water from industrial brine and reduce the remainder to solid salt. 

The team’s approach involves pretreating Nestle’s brine to remove larger particles.  It then goes through a reverse osmosis process that results in a stream of high-quality water and a salty concentrate.  The salty concentrate goes through a special membrane that recovers even more pure water.  The highly concentrated brine is then dried and crystalized into a solid salt product.  Atmospheric water harvesters capture any remaining water vapor during the drying process.

In places like Arizona where freshwater is a scarce commodity, finding sustainable ways to separate water from salt is both a scientific challenge and an economic necessity.

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Squeezing every last drop out of wastewater

Photo courtesy of the Global Center for Water Technology.

Earth Wise is a production of WAMC Northeast Public Radio

The Colorado River crisis

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The Colorado River serves nearly 40 million people in seven U.S. states and Mexico.  It provides water for 5 million acres of farmland.  Increasing demand from growing populations, damming, diversion, and drought have been draining the Colorado at alarming rates.  This critical resource supports countless economies, communities, and ecologies stretching from the Rocky Mountains to the Gulf of California.  The Colorado River essentially has made the cities of Las Vegas, Los Angeles, Denver, and Phoenix possible.

How the water of the Colorado is distributed is determined by an agreement that is over 100 years old:  the Colorado River Compact.  It was made at a time when people thought there was more water than really was there.  And at the time, no one thought that the seven states would need to use the water they were allocated down to the last drop.

There have been various measures over the years to conserve water from the Colorado River, including the Colorado River Interim Guidelines in 2007.  Those guidelines will expire in 2026 and negotiations are beginning to take place among the many stakeholders scrambling for water rights.  Apart from the seven U.S. states and Mexico, there are 30 tribal nations involved.  Collaborative governance is complicated when it crosses multiple jurisdictions with their own laws and legal precedents.  The goal is to put in place a new agreement to protect the Colorado River.

Rapidly-growing populations in major cities, a 20-year megadrought, and historically low water levels in America’s two largest reservoirs have put enormous pressure on the Colorado River.  Creating a plan to protect the lifeblood of the American West is essential.

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Addressing the Colorado River crisis

Photo, posted June 18, 2022, courtesy of Jeff Hollett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Who’s driving electric?

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Electric cars are growing in popularity around the world and are expected to represent 20% of new car sales this year.  In some places, they have a much bigger share:  38% in China and a whopping 82% in Norway.  Here in the U.S., things are more complicated.

Last year, EVs represented 8.5% of U.S. new car sales while hybrids accounted for an additional 10%.  But enthusiasm for plug-in vehicles was by no means universal or consistent across the country or across various segments of the population.

Overall, the West Coast, and especially California, dominated the electric vehicle market.  Electric vehicles accounted for more than 30% of new car sales in the San Francisco Bay Area.  In Los Angeles, the number was close to 25%.

A number of metro areas elsewhere also had strong EV sales, including Denver, Las Vegas, Washington DC, Austin, and Phoenix.  New York City had almost 10% EV registrations. 

Americans buying electric cars so far tend to be richer, younger, and more likely to live in urban areas than the average person and are often motivated by environmental concerns.  Meanwhile, about half of American adults say they are not likely to consider purchasing an EV as their next car and that figure rises to 70% for Republicans.

Lack of interest in EVs is often based on concerns about the availability of sufficient charging options or high EV prices, although those are dropping.  There is also concern about EV efficiency in colder climates, although the Norwegians clearly don’t find it to be a problem.

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Electric Vehicles

Photo, posted October 18, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Why Was the Summer So Hot? | Earth Wise

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Many places around the world have experienced extraordinary heat waves this summer.  The 31 days of high temperatures 110 degrees or more in Phoenix is a prime example but many other places suffered from extreme and relentless heat.  Why did this happen?

The overarching reason is climate change, which has warmed the Earth by 2.2 degrees Fahrenheit since the preindustrial era.  This change on a global level is enough to make heatwaves far more likely.  For example, the concurrent heatwaves in Europe and North America were 1000 times more likely to have occurred because of climate change.

But there hasn’t been a sudden increase in global temperature that would make this summer so much hotter.  Instead, what really has happened is three other factors all came into play at the same time.

The first is the 2022 eruption of Hunga Tonga-Hunga Ha-apai, which is an underwater volcano in the South Pacific.  That eruption did not produce much in the way of planet-cooling aerosols in the atmosphere.  Instead, it vaporized huge amounts of seawater, sending water vapor into the atmosphere, which helps trap heat.

The second is a change in the amount of energy radiating from the sun.  That actually rises and falls a small amount every 11 years.  Currently, it is in the upswing and will reach its next peak in 2025.

Finally, there is the arrival of the El Niño in the Pacific, whose balmy ocean waters radiate heat into the air.

The combination of all these factors when added to the already warming climate is a recipe for temperatures to soar to uncharted highs.  We can expect more heat waves, forest fires, flash floods, and other sorts of extreme weather.

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It’s Not Just Climate Change: Three Other Factors Driving This Summer’s Extreme Heat

Photo, posted February 27, 2017, courtesy of Giuseppe Milo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Phoenix Is Frying | Earth Wise

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The mythical Phoenix is a bird that repeatedly dies in a fire of its own making.  During July, the five million inhabitants of greater Phoenix Arizona may have felt like they were reliving that myth as multiple temperature records were shattered in a massive heatwave.

On June 30, the high temperature in Phoenix was 110 degrees.  From then on, the daily highs were relentlessly at or above 110 degrees, topping out at 119 on July 20.  The previous record for consecutive days at or above 110 was 18 set in June 1974.  The streak continued all the way until July 31, when incoming desert monsoons resulted in the high temperature dropping to 107 degrees – ending the streak at 31 days.  Along the way, there were 16 days with temperatures at or above 115 degrees. 

During the month, there were 17 consecutive days when the lowest temperature in Phoenix was at least 90 degrees.  The previous record for that was 7 days, set in 2020.  Because of these lofty low temperatures, July was also the hottest month in terms of average temperature with a reading well above 102 degrees.  It was the first time that the average temperature has ever been in three digits.  The previous record was 99.1 degrees in 2020.

Phoenix is an extreme case, but it was not alone in having a hot July.  Globally, it was the hottest July on record that included major heat waves in the U.S., Mexico, China, southern Europe, and elsewhere.  The daily record for the hottest average temperature on Earth ever measured was also broken several times during the month.

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Phoenix heat wave is shattering temperature records

Photo, posted September 22, 2022, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water For Arizona | Earth Wise

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The Phoenix area is the fastest growing region in the country.  Arizona’s two major sources of water – groundwater and the Colorado River – are dwindling from drought, climate change, and overuse.  Officials in the state are considering a radical plan to construct a desalination plant off the Mexican coast that will take the salt out of seawater, and then pipe that water hundreds of miles, much of it uphill, to Phoenix.

The project is the brainchild of the Israeli company, IDE, which is one of the world’s largest desalination companies.  IDE has asked Arizona to sign a 100-year contract to buy water from the project. 

There are multiple complications surrounding the plan.  Desalination plants are common in California, Texas, and Florida, and in more than 100 other countries.  But the Arizona project is unusual because of the distance involved and because the state is landlocked.  The water would have to travel 200 miles and climb 2,000 feet along the way.

There is also the issue of waste brine, which is a major output of desalination plants.  In this case, the brine would flood the northern Gulf of California, potentially threatening a productive fishery.  In addition, the pipeline, as well as electrical transmission lines, would have to go through the Organ Pipe Cactus National Monument, a UNESCO biosphere reserve.

The plant would be located in Puerto Peñasco, a struggling town with its own water problems.

With booming home construction going on in the Phoenix area, the need for more water continues to grow.  Whether this plan will be approved by Arizona and by Mexico remains to be seen.

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Arizona, Low on Water, Weighs Taking It From the Sea. In Mexico.

Photo, posted September 26, 2008, courtesy of Dan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Storms And The Megadrought | Earth Wise

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California experienced its wettest 10-day period in 25 years as a result of a series of storms driven by atmospheric rivers in January.  The Rocky Mountains got buried in snow from the same weather pattern.   For the drought-stricken West, the storms were good news.  But they are not the cure for what’s been ailing the region.

In California, the snowpack in the Sierra Nevada mountains has been greatly enhanced, containing twice as much snow as is considered average for this time of year.  Without a doubt, it will reduce the impact of the drought that has plagued the state for 23 years.  But one big storm or even a series of them is not enough to undo years of minimal precipitation and rising temperatures.  Many of the states’ largest reservoirs remain well below historical averages despite the record-breaking rain.  It would take several wet years to really allow the state to recover from the drought.

The snowfall in the Rockies is crucial because it is the source of more than two-thirds of the water in the Colorado River.  The Colorado River is the water lifeline for 40 million people from Wyoming to Mexico.

The ongoing shrinking of the Colorado River is a crisis that has created massive problems for the multibillion-dollar agriculture industry and for many large cities, including Denver, Phoenix, Salt Lake City, Las Vegas, and Los Angeles.  Two of the nation’s largest reservoirs – Lake Mead and Lake Powell – are filled by the Colorado River.  The historic low levels of these reservoirs have threatened the functioning of hydropower facilities that provide electricity to millions of people.

The January storms were good news for the West, but its problems are not over.

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This Winter’s Rain and Snow Won’t be Enough to Pull the West Out of Drought

Photo, posted September 18, 2022, courtesy of Sarah Stierch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Harvesting Fresh Water From Ocean Air | Earth Wise

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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

Forests And Water | Earth Wise

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We hear a great deal about the environmental services provided by forests.  Deforestation is one of the major factors contributing to increasing levels of carbon dioxide in the atmosphere.  And, of course, forests – most notably rainforests – are major contributors to biodiversity.  A new study by the U.S. Forest Service looked at the role forests play in providing water for Americans.

According to the study, published in the journal Water Resources Research, forested lands across the U.S. provide 83 million Americans with at least half of their water.  125 million people – well over a third of the country – receive at least 10% of their water from forests.  Notably, in the drought-stricken western U.S., nearly 40 million people get more than half of their drinking water from forests that are increasingly threatened by wildfires.

The study looked at surface water sources for more than 5,000 public water systems.  It provides a critical update to the map of where our water comes from.  The study focused on surface waters such as lakes, rivers, and streams because it is too difficult to trace sources of groundwater on a national scale.  Included is a new database of inter-basin water transfers, which are how surface water moves from places where it is plentiful to where it is not.  Examples are the California Aqueduct and the Central Arizona Project which respectively supply Los Angeles and Phoenix with drinking water.  

In Los Angeles, 69% of the water coming in through inter-basin transfers originated in forested lands.  In Phoenix, the figure is 82%.  There are many urban communities that obtain more than half of their drinking water from inter-basin transfers.  Even far from forests, water from forests is essential for millions of Americans.

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U.S. Forests Provide 83 Million People with Half Their Water

Photo, posted September 26, 2016, courtesy of Don Graham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Widespread Drought | Earth Wise

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As the U.S. enters the last part of the summer, fully one-third of the country is experiencing at least a moderate level of drought.   Much of the West is reaching severe drought conditions and New England has been unusually dry and hot.  In total, over 50 million Americans are living in drought-affected areas.

According to the U.S. Drought Monitor program, more than 93% of Utah, Colorado, Nevada, and New Mexico are experiencing drought to some degree.  More than 60% of both Utah and Colorado are in severe drought.   More than three-quarters of Oregon, Arizona, and Wyoming are also in drought.  And most of these areas had no sign of drought this time last year.

Severe drought conditions result in stunted and browning crops, limited pasture yields, dust storms, reduced well water levels, and an increase in the number and severity of wildfires.

Warm air temperatures and minimal snowfall in spring set the stage for this summer’s drought conditions.  A ridge of high pressure over the northeastern Pacific Ocean pushed the jet stream farther north than usual.  And, once again, there has been a failure of the southwestern monsoon in Arizona and New Mexico and the Four Corners region.  Monsoon rains provide half of the year’s precipitation in many of those areas. 

Instead, there has been extreme heat in the region.  Phoenix has already smashed the record for the most days over 110oF in a calendar year (42 as of August 18), with five months to go.  Las Vegas hasn’t seen measurable rainfall since April, and Cedar City, Utah has recorded a record low of 0.05 inches of rain this summer.

Conditions are not expected to get better for a couple of months.

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A Third of the U.S. Faces Drought

Photo, posted May 7, 2014, courtesy of Tyler Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Urban Agriculture And Sustainability Goals

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In 2016, the City Council of Phoenix, Arizona adopted eight Environmental Sustainability goals for 2050 that lay out the desired long term requirements in order to become a Sustainable Desert City.  Recently, a group of researchers from Arizona State University assessed how urban agriculture can help Phoenix, a desert city of 1.6 million people, meet those sustainability goals.  

Using public records and high-resolution satellite imagery, researchers analyzed the potential benefits of growing crops in three types of urban areas in Phoenix: vacant lots, rooftops, and building facades.  The study, which was supported by the National Science Foundation and the USDA, estimated that there are 28 square miles (or 5.4% of city space) available for urban agriculture.  The data-driven analysis found that 71% of the available areas for urban agriculture would come from existing buildings as opposed to vacant lots. 

All this available space for urban agriculture in Phoenix could supply the city with nearly 183,000 tons of fresh produce annually, which would allow for the delivery of fresh fruits and vegetables to all of the city’s existing food deserts. In fact, the city’s own urban-agriculture output could meet 90% of the fresh produce demand that currently exists in Phoenix. 

In addition to producing food, rooftop agriculture could also reduce the energy use in buildings by 3% per building per year, and displace more than 55,000 tons of CO2 annually.  The use of vacant lots could increase the total Phoenix green space by 17%, and reduce the number of areas lacking green space by 60%.   

This study demonstrates the many different ways that urban agriculture can benefit a city. 

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Urban agriculture can push the sustainability

Photo, posted May 10, 2011, courtesy of Stephen Zank via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Off-The-Charts Heat

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There have been some blistering heatwaves this summer – in Europe, in the Middle East, and here in the United States.  A new report by the Union of Concerned Scientists projects that within the next 20 years, millions of people in the United States could be exposed to dangerous “off-the-charts” heat index conditions of 127 degrees Fahrenheit or more.  Within 60 years, over one-third of the population could be exposed to such conditions.

Extreme heat kills hundreds of people every year across the U.S.  Our bodies’ natural cooling process is affected by humidity and the combined heat index measures the impact of high temperature and high humidity.  When the combined heat index reaches 90 degrees, it is considered to be a “dangerous day”, when many groups of people are at serious risk.

Because of the warming climate, the number of dangerous days has been increasing in many parts of the country.  Unless there is success in limiting the effects of climate change, by 2050, even relatively temperate cities like Detroit, Minneapolis, New York, and Chicago will have 50 or more dangerous days a year.  Places like Dallas, Houston, Phoenix and Miami will experience dangerous days for half of the year.

The National Weather Service’s heat index goes up to 127 degrees Fahrenheit.  But in as soon as 20 years, the Southeast, Southern Great Plains, and Midwest will begin to experience days that are so hot that they are “off the charts.”

These extreme conditions could still be avoided with steep, rapid carbon emission reductions.  But however successful we are going forward, the US will still be significantly warmer than today with 85 urban areas exposed to 30 or more days with a heat index above 105 degrees, compared with just three urban areas historically.

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‘Off-the-charts’ heat to affect millions in U.S. in coming decades

Photo, posted August 8, 2008, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Trouble On The Colorado

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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.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)