Cleaning the watershed, protecting farmers’ bottom lines

When farmers on Virginia’s Eastern Shore were told they had to curb the amount of nitrogen and phosphorous seeping from their fields into the Chesapeake Bay, Zach Easton stepped in to find a solution. Easton, an assistant professor of biological systems engineering, may have found a way to save the bay while maintaining farmers’ profits with the development of a bioreactor buried under the coast’s fertile agricultural grounds.

“The ultimate hope is that this will be a cost-effective system that producers can use to protect water quality and help keep agriculture profitable in Virginia,” said Easton, a Virginia Cooperative Extension specialist whose research is conducted at the Eastern Shore Agricultural Research and Extension Center in Painter.

Zach Easton

Zach Easton, left, an assistant professor of biological systems engineering, explains how his new bioreactor curbs pollution in the Chesapeake Bay to Mary Leigh Wolfe, head of BSE, and Saied Mostaghimi, the college’s associate dean for research and graduate studies.


Easton recently received a $120,000 grant from Virginia’s secretary of natural resources to test and demonstrate his bioreactor at four different sites around the state. The hope is to have the bioreactors ready for commercial use by 2017, when a new set of environmental regulations takes effect.

The rules mandate that farmers reduce the nitrogen and phosphorous reaching the bay by as much as 30 percent. Easton’s new bioreactor far surpasses that by removing up to 90 percent of nitrogen and 45 percent of phosphorus. It costs about $260 an acre — a one-time expense over its 15- to 20-year lifespan — which is much cheaper than some other solutions.

The bioreactor is a large, underground vat that is filled with wood chips. Water from the fields is funneled toward the container, where microorganisms feed off the wood chips and nutrients in the water. Because it is buried, there is little loss of productive land.

During the feeding process, the microorganisms convert nitrogen in the water into harmless nitrogen gas that makes up 78 percent of the atmosphere. They incorporate the phosphorus into their microbial biomass. The added substrate, biochar, can also remove phosphorus from the water.

“We believe this is an economic and viable solution to curb water pollution while protecting farmers’ bottom lines,” Easton said.

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