Used beer yeast can remove lead in water

Study Says, Surplus Brewing Yeast Can Clean Lead Contaminated Water

Researchers at the Center for Bits and Atoms (CBA) in MIT have found that inactive yeast could help remove lead contamination from drinking water. The team studied a type of yeast widely used in brewing, called S. cerevisiae, on pure water spiked with trace amounts of lead. They found that a single gram of dried, inactive yeast cells can remove up to 12 milligrams of lead in aqueous solutions. They also found that the process takes less than five minutes.

A significant problem that continues to grow globally is the presence of lead and other heavy metals in water because of discharges from mining operations and electronic waste. Lead is highly toxic. The European Union has reduced the standard for allowable lead in drinking water to five parts per billion from 10 parts per billion. The Environmental Protection Agency, US, has declared that lead is unsafe in water supplies even at the tiniest concentration.

Patritsia Statahou, Research Scientist at MIT, has estimated that to clean a water supply for a city that uses about 200 million gallons of water a day would require about 7,000 tons of yeast per year. By comparison, the Boston Beer Company, a single brewery, generates 20,000 tons a year of excess yeast that is no longer useful for fermentation.

The study shows that this surplus yeast can remove less than one part per billion levels of lead contamination. This approach can be effective, inexpensive, and economical.