According to the university, civil and environmental engineering professor Guanghui Hua and agricultural and biosystems engineering professor Chris Hay have been testing rusty carbon steel shavings as a filtration media for removing phosphates.

Phosphorus and nitrogen are important as crop fertilizers, but when they wash into rivers and streams, they encourage algae growth. And that’s a problem because algae consume oxygen in the water, smothering other aquatic life. And some species of algae release toxic substances.

Dissolved phosphorous is hard to remove, but the researchers are finding that rusty scrap steel might be an effective filtration media -- iron oxides bind with phosphate ions and take it out of the water.

Researchers have been testing four types of steel shavings obtained from Sioux Falls, S.D., USA, machine shops. Laboratory results have been impressive – they’ve been able to consistently remove all of the phosphate from simulated water runoff, the university said.

They plan to conduct a field test this fall.