Woodchips are dumped into a lined bioreactor trench at Oakland View Farms on Maryland’s Eastern Shore.
For years, environmentalists have been searching for a breakthrough in their efforts to clean up the Chesapeake Bay. And now, they think they’ve found that breakthrough — in the form of the humble woodchip.
The Midshore Riverkeeper Conservancy in Easton, Md. is working with several farmers on the Eastern Shore to install “woodchip bio-reactors” on their farms. These are basically underground systems that collect water from farmland before it goes into rivers, and filters it through a pile of woodchips. Those woodchips are home to tiny bacteria that love to eat nitrate, the pollution that can create algae blooms and dead zones in the bay.
We recently caught up with Drew Koslow, the Choptank Riverkeeper, to learn more about how these systems work. We spoke with him at Mason Heritage Farm, one of the farms getting a woodchip bio-reactor.
How Does It Work?
“Well a lot of farms on the Eastern Shore have drain tile networks or drainage ditch networks to remove excess water and allow them to get onto their fields in the springtime. This farm is no exception, as is the other farm where we installed one of these bio reactors,” says Koslow.
“And what we’re doing is taking advantage of the water collection system, whether it’s the ditch or in these cases the drain tile network and we’re running that water through a natural filter. That’s the woodchips. So the woodchips provide an environment for bacteria that eat the nitrate, which is the mobile form of nitrogen, out of the water. And they convert it to nitrogen gas, which is 70 percent of the air we breathe. And the beauty of it is that it’s a natural process. The contact the water has with woody vegetation, with plant material and the flood plain, that’s where you get your nutrient processing."
"So what we’re doing is putting that into a confined area, the woodchip pit, and running our water through and trying to keep as long a retention time of the water in the woodchips as we can. And each site is going to be a little site-specific, but in Iowa, where these things were developed, they found to be very effective at removing nitrate, relatively inexpensive to put in the ground, edge of field technology so you don’t take land out of production. And very low-maintenance over their life span, which is between 15 and 30 years."
How Environmentalists and Farmers Are Working Together On this Project
“We feel like as difficult as it is, as uncomfortable as the relationship is between environmental groups and farmers, it’s in each of our best interests to try to work together, to try to develop practices that are going to work so that we have tools so that we give farmers tools to help them meet our goals,” says Koslow.
“The potential difference that this kind of project can make is really large, and the beauty of it is it’s a one-time installation and you let the project do its job. Cover crops are a very efficient way at removing nitrate, but you have to reapply them every year and sometimes your weather conditions will prohibit you from doing that."
"This kind of project, you put it in the ground, you do your monitoring, as soon as you see your efficiencies drop, your performance of the project drop, you can excavate out your woodchips and replace them and you’re back up to the design efficiency of your project."
"I’ve been saying this, I’ve been in the business for 20 years and I’ve always said, if you want to see what a polluter looks like, look in the mirror. In my mind, we’re all in this together and the more collaboration, particularly between groups that are typically adversarial, you know, the more collaboration you get the better.”
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