necessity

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

Wyoming produces about 40% of our country’s coal and many towns in the state were built because of and make their living from it. With coal’s plummeting share in the nation’s electricity, there is a great deal of anxiety among residents of those towns.

As carbon dioxide levels in the atmosphere continue to climb, there is a growing sense that cutting emissions will not happen quickly enough and it will be necessary to pull the greenhouse gas out of the atmosphere. The current long-term government climate strategy assumes that carbon removal will account for 6 to 8 percent of the nation’s greenhouse gas reductions by 2050.

The Inflation Reduction Act passed in August provides $3.5 billion to help build “direct air capture hubs” around the country, with an emphasis on fossil fuel-dependent communities such as many in Wyoming.

The town of Rock Springs, Wyoming is home to the Jim Bridger Coal Plant. A company called CarbonCapture, Inc., is launching Project Bison, which will build a direct air capture facility outside of town that is set to begin operations next year. It will initially capture 10,000 metric tons of CO2 per year but plans to expand that to 5 million tons a year by 2030.

That would be far more than any current carbon capture plant can do. The largest plant in the world, located in Iceland, pulls in only about 4,000 metric tons a year.

There are many problems associated with carbon capture. It uses up very large amounts of energy, possibly presents environmental problems, and is very expensive. In short, the technology has a long way to go before becoming viable. However, this may ultimately be another example where necessity is the mother of invention.

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Carbon Removal Is Coming to Fossil Fuel Country. Can It Bring Jobs and Climate Action?

Photo, posted July 22, 2012, courtesy of Max Phillips via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio