Can Cows, Manure, and Algae All Add Up to Clean Water? Lessons from Charlotte, Vermont

Carolyn Dube

Innovation continues to thrive in the Green Mountain State. The Nordic Farm is looking at using algae to turn manure and other biological waste into fuel and fertilizer.

The farm’s dairy barn is home to 300 cows. These ladies produce more than a ton of manure every day. That’s a lot of waste. Seventeen dairy farms in Vermont are already equipped with anaerobic digesters to help tackle the constant supply of manure. These digesters provide manure with a second life. They harvest methane gas from the manure and use it to produce electricity for the farm or electric grid. Green Mountain Power distributes what has come to be known as Cow Power to customers all over the state.

Even though Cow Power is able to harvest a valuable product from manure, one byproduct of anaerobic digestion is a nutrient dense liquid. Since farmers need to apply this liquid when it is produced, its use is often an inopportune time during the year when the Vermont landscape is already overburdened with nutrients. The excessive nutrients then run off the land and cause water pollution.

The technology being explored at Nordic Farm takes a step beyond anaerobic digestion.

The farm is working with GSR Solutions President Anju Dahiya to introduce algae to the liquid waste as a means to both eliminate the harmful byproducts of anaerobic digestion and put them to good use.

A special strain of algae is introduced to the liquid byproduct of the anaerobic digestion. The algae feed on the liquid waste and produce a crude oil biofuel that can be used in place of motor oil. It also produces a dry fertilizer. The fertilizer is granular and can be stored and used later on the farm, or shipped to farms at other locations.

The nutrients in the original liquid byproduct are concentrated in the dry fertilizer. Farmers can import less fertilizer, and reduce the overall load of nutrients coming on to the farm and threatening our waterways.

Reducing nutrients on farms is critical to cleaning up Lake Champlain and eliminating the numerous beach closures we’ve seen far too much of on Lake Champlain this summer.

While the technology has a long way to go before Vermonters will be filling their diesel cars with algae fuel, or buying algae fertilizer at the garden store, it is exciting to see what creative innovation can mean for our farms, for climate change and our waters.

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2 Responses to “Can Cows, Manure, and Algae All Add Up to Clean Water? Lessons from Charlotte, Vermont”

  1. James Maroney

    All cows poop but the article does not mention the nutrient that farmers do not need 40,000 tons of which they voluntarily import: NPK fertilizer. Nitrogen can be supplied by rotating corn with legumes which miraculously pulls the element out of the air and deposit it in the soil not in a soluble form so it does not run off. I might add that since Nordic Farm is conventional, nothing they do other than repudiate the conventional paradigm will lead to clean water. CLF has been hoodwinked into supporting manure digesters as a solution that helps farmers protect water quality.

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