06:12 PM MST on Wednesday, September 10, 2003

By David Wichner
© 2003 © 2003 Arizona Daily Star

University of Arizona researchers have discounted fears that a pathogen found in sewage could be transmitted to humans via treated sludge used as fertilizer.

The UA National Science Foundation Water Quality Center found that Staphylococcus aureus, a human disease pathogen present in raw sewage, does not survive federally required treatment of "biosolids," or sewage sludge products.

The findings, due to be published next month in the journal Environmental Science and Technology, mean municipal water-treatment plants can safely dispose of treated sewage without risking exposure to the pathogen.

An adverse finding could have had major implications for water-treatment plants and agriculture.

"This is good news," said Ian Pepper, director of the UA water-quality center. "We couldn't find staph-aureus — we've shown the treatment has eliminated that."

Pepper noted that nationally, 60 percent of treated biosolids are applied to land, while in Tucson the number is close to 100 percent.

The biosolids work is being funded through the center's main budget, which is supported by the National Science Foundation, government and industrial sources. The center is the only NSF-funded water quality center in the U.S.

The center is part of an ecological sciences base at the UA that was identified by a Battelle Memorial Foundation report earlier this year as one of the most promising areas for future technology commercialization and economic development.

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