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Constructed Wetlands Friendly to Environment, Farmers

By Kevin Foley Article published June 23, 2004

Aleksandra Drizo
Aleksandra Drizo (center) leads a tour of the newly built "constructed wetland" on Spear Street. (Photo: Sally McCay)

It's not glamorous, but it sure is practical: A constructed wetland is scooped out of the ground with an earthmover, lined with local gravel, and linked to a barnyard with plastic pipes. Gravity draws the wastewater downward through the underground gravel cells, into a collection tank, and then disperses it over a swale, cleaned of its suspended soil and organic matter.

Such a wetland is also extremely environmentally friendly, says Aleksandra Drizo, research assistant professor of plant and soil science and the project manager of a prototype constructed wetland at the Paul Miller Research Center on Spear Street. The UVM wetland, which was first discussed in 2001 and went online in October, 2003, is designed to show Vermont’s farmers the possibilities of an inexpensive innovation in agricultural water treatment that is widely used in Europe and other states but almost unknown here.

“It’s simple, cheap and doesn’t require any energy to operate,” says Drizo, who came to UVM in February, after Cully Hession, assistant professor of civil and environmental engineering, Don Ross, research assistant professor of plant and soil science, Donald Foss, Miller Manager Greg Eurich and others developed the wetland.

With about $250,000 in current funding from the United States Department of Agriculture, money obtained by Sen. James Jeffords, Drizo is applying for additional grants and working with a team of three undergraduates and two graduate student to monitor the UVM wetland’s performance and assess new technologies.

Drizo, whose previous research involved testing more than 60 materials for their ability to remove phosphorous, a major cause of lake pollution and algae blooms, from domestic and agricultural wastewater, will install new filters over the next month in a test area of the wetlands to monitor the effectiveness of various techniques and compounds in removing the chemical. In that research, tubes filled with a type of slag, a cheap byproduct of steel production, proved highly effective at filtering phosphorous. Drizo’s goal now is to find sources of similar material in the Northeast and develop techniques that maximize its life as a filter. The work, she says, grows in importance as the regulatory landscape shifts.

“I believe that farmers will be obligated sooner or later to have a treatment method to control this kind of pollution,” Drizo says.

Another significant parameter being tested at the facility is the use of aquatic plants, in this case river bulrush, to improve the wetland’s effectiveness. Two of the 40-by-60-foot wetland cells are planted, the other two left as a control. Weekly water testing will compare the results between the two areas.

As the group works on phosphorous removal techniques and gathers enough data for research presentations on the system’s overall performance, they will also broaden their outreach work, introducing farmers to the technology’s potential with workshops, tours, consulting and a Web site. Drizo will approach this phase of her job with zeal.

“I really love what I do and believe in it with all my heart,” she says.