Building on Biodigesters. I'm Greg Martin as Line On Agriculture presents the Harvest Clean Energy Report.
Our series on Building the Biocarbon Economy continues this week as we delve into the world of the biodigester. Patrick Mazza, Research Director for Climate Solutions, has written this series to take a look at how all these parts and pieces are interrelated to help the northwest use these clean technologies to increase our energy economy.
MAZZA: The challenge with biodigesters in northern locations of the U.S. has been a high failure rate; failures have been in the 50% range. Washington State has been moving to solve these problems through work between Washington State University, Washington Department of Ecology and a partner in Lynden, the VanderHaak Dairy.
Mazza says that developing successful biodigesters is really about creating multiple product streams.
MAZZA: And this is to solve what has been a problem with biodigesters which is simply economics. Biodigesters do really useful things for dairy farmers, they help manage manure. As any dairy farmer knows this is a big challenge both in terms of odors and nutrient management so what a biodigester does is take that manure and process it down into several different, valuable products.
More revenue streams equals a more stable financial business base to continue operating the digesters. At the VanderHaak digester they have 9 product streams.
MAZZA: They process manure from 700 cows and that enabled shutdown of a dairy lagoon. This resulted in reduced methane emissions that can be marketed for carbon credits. What happens is instead of methane being emitted from the pond it's processed through the biodigester as biogas and is run through an electrical engine so that becomes another product.
That electricity is then sold back to the power companies. Other products include a peat moss substitute and in some cases commercial food waste is co-digested helping to eliminate the disposal of the garbage. Also the liquid extracted makes a good fertilizer.
MAZZA: Washington State University has developed a new process to take the liquids and make them into solids so they're working on solid nitrogen and phosphorus fertilizers and then finally the liquids that remain can still be applied to local farms so you have all these values coming off of that. This example of success has really generated a lot of biodigester action in the northwest.
For additional information on clean energy, visit harvestcleanenergy.org. That's today's Line On Agriculture. I'm Greg Martin on the Ag Information Network.