waste product

Flow batteries are rechargeable batteries in which liquid electrolytes flow through one or more chemical cells from one or more tanks. The electrolytes are redox pairs, that is, chemical compounds that can reversibly undergo reduction and oxidation reactions. The most common redox electrolytes include elements like vanadium, chromium, iron, zinc, and bromine. Flow batteries can provide large amounts of both electrical power and stored energy based on the size of the electrolyte tanks. As a result, they can be scaled up far more readily than other battery technologies.

Flow batteries are safe, stable, long-lasting, and their electrolytes can easily be refilled. They have significant potential for use in utility-scale storage for renewable energy systems.

Researchers at Northwestern University have developed a redox flow battery based on an organic industrial-scale waste product. The material – triphenylphosphine oxide or TPPO – is produced in the thousands of tons each year. It is byproduct of producing a variety of substances including some vitamins, pharmaceuticals, agrochemicals, and other bulk chemicals. For the most part, TPPO is of little use and must be carefully discarded.

The current market for redox flow batteries is very small but is expected to grow over time as the need for utility-scale energy storage continues to expand. A battery technology based on a waste material that is already produced in high volume and that must otherwise be disposed of with caution would have significant advantages.

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Green battery discovery turns trash into treasure

Photo, posted January 12, 2015, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lead and other heavy metals in water are a serious global problem that is worsening because of electronic waste and discharges from mining operations. In the U.S., over 12,000 miles of waterways are impacted by mine-drainage water that is rich in heavy metals.

Lead in particular is highly toxic, especially to children. The European Union established a standard for allowable lead in drinking water of only 5 parts per billion. In the US, the EPA has declared that no level of lead at all is safe.

Researchers at MIT have recently discovered that inactive yeast can be effective as an inexpensive, abundant, and simple material for removing lead contamination from drinking water supplies. The MIT study shows that the method works even at parts-per-billion levels of contamination.

The method is called biosorption, in which inactive biological material is used to remove heavy metals from water. Previously, it has been studied at parts-per-million contaminant levels, but the MIT study shows that it works at much lower levels as well.

The team studied a type of yeast widely used in brewing. The yeast cells used are inactive and desiccated and require no special care. Such yeast is abundantly available as a waste product from beer brewing and various other fermentation-based industrial processes.

The researchers estimate that to clean a water supply for a city the size of Boston would require about 20 tons of yeast a day, or 7,000 tons a year. That seems like a lot, but one single brewery, the Boston Beer Company, generates 20,000 tons a year of surplus yeast that is no longer useful for fermentation.

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Could used beer yeast be the solution to heavy metal contamination in water?

Photo, posted September 5, 2017, courtesy of Allagash Brewing via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A green battery from industrial waste

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Removing Lead From Water With Beer Yeast | Earth Wise

Lead and other heavy metals in water are a serious global problem that is worsening because of electronic waste and discharges from mining operations. In the U.S., over 12,000 miles of waterways are impacted by mine-drainage water that is rich in heavy metals.

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