Air Date: Week of July 27, 2001

Living on Earth's Maggie Villiger reports on a inexpensive way to clean up storm runoff.

Transcript

CURWOOD: Mexico City gets through a year without a smog alert. And Antarctic seals with strange mating habits. First, this environmental tech note from Maggie Villiger:

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VILLIGER: After falling to the earth, rainwater can pick up oil, gasoline, and other pollutants as it travels across roads and highways. These contaminants eventually end up in local waterways. Recently, a scientist at the University of Rhode Island devised a cheaper method to remove harmful pollutants from storm runoff. The researcher had been studying the effectiveness of storm water detention ponds in Providence. These ponds were designed to capture excess rainwater and filter out contaminants before the water reached Narragansett Bay. Pollutants latch onto sediments and organic material in the pond water. This heavier material then settles to the bottom of the ponds. The cleaner water flows out and into the Bay. But the researcher noticed that heavy rains decreased the pond's effectiveness. If the water flowed through the pond too quickly, the pollutants didn't have time to settle before flowing into the Bay. So additional material was needed to filter more effectively. In lab tests, the researcher discovered that shredded Aspen wood -- an inexpensive and non-toxic material -- filters out 97 percent of pyrene, a contaminant in roadway runoff. About 100 pounds of shredded wood in the ponds would be needed to aid in the filtration process. Once the lab experiments are completed sometime next year, the filtration system will be field tested in the ponds. That's this week's Technology Note. I'm Maggie Villager.

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CURWOOD: And you're listening to Living On Earth.

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