John Tolley, December 19, 2018

Sometimes, nothing can beat a gentle rainstorm; the fresh smell, the feel of the damp air, the clean and nourishing ambience it lends to the earth.

But as rain falls and runs along and through the soil, it picks up passengers. Fertilizers, chemicals, heavy metals, and microplastics wash along in the runoff from a storm, beating a path for ever larger waterways. This laden effluvia can wreak havoc on ecosystems.

Take for instance the Chesapeake Bay, which swallows up the runoff of the urban centers, suburban enclaves and vast agricultural lands that surround it. Phosphorous and nitrogen fertilizers, used on lawns and fields alike, encourage the growth of algae and other microbes whose eventual death strips precious oxygen from the water and promotes dead zones in the bay.

To combat this problem, researchers at the University of Maryland are working on a number of solutions. One in particular makes use of a byproduct of the water treatment process normally discarded as waste.

Allen P. Davis, the Charles A. Irish Sr. Chair in Civil Engineering at the University of Maryland's Clark School of Engineering, has been developing the use of the aluminum-based material in the sequestration of fertilizers for 10 years. He has designed basins, impregnated with this material, that serve as a collection point for runoff stormwater. The first was installed on the College Park campus in 2011.

"Each basin will include an aluminum-based material traditionally discarded as waste from the drinking water treatment process," said Davis, speaking with the Clark School's news service. "When phosphorus interacts with this material, it binds to it, trapping the pollutant in the basin."

Now, the university, in collaboration with The Clean Water Partnership and The Low Impact Development Center will install six bioretention basins in Suitland and a few other select Maryland communities to test their effectiveness on a larger scale.

With help from graduate student Blake Wang, Davis will monitor the basins and collect information on phosphorous, nitrogen and sediment levels. That information will be made available to municipalities and governments around the state, in hopes that they will see utility in the adoption of such measures.