Cleaning up pollution, whey down deep

From Baltimore, at the American Geophysical Union meeting

Lab and field tests hint that dairy whey, a lactose-rich by-product of the dairy industry, could be used to clean up underground water supplies tainted with the solvent trichloroethylene (TCE), an industrial degreaser.

Consuming TCE or inhaling its fumes can cause liver and kidney damage, affect heart function, and possibly cause cancer (SN: 5/29/99, p. 343: http://www.sciencenews.org/pages/sn_arc99/5_29_99/fob6.htm). The chemical is in groundwater at more than half of the Environmental Protection Agency’s Superfund sites.

To treat the tainted groundwater, engineers often pump hydrogen-yielding substances such as sodium lactate into the ground, where they react with TCE by removing its chlorine atoms. That turns it into a relatively harmless hydrocarbon, says Elizabeth S. Semkiw, a chemist at Western Michigan University in Kalamazoo.

Her team’s tests indicate that a slurry of whey pumped into the ground may do the same trick, if sufficient numbers of bacteria are added. Whey-munching microbes generate lactate compounds as well as acetates, butyrates, and other substances that can strip chlorine atoms from TCE.

In the lab, a whey-microbe mix eliminated a 10-parts-per-million concentration of the pollutant from simulated groundwater in less than 2 weeks, says Semkiw. Also, field tests showed that groundwater laced with TCE, after flowing through a subterranean curtain of whey, contained breakdown products of the chemical.

Further tests will assess whether remediation with whey is more cost-effective than the use of chemicals such as sodium lactate, says Semkiw.

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