Finnriver Farm & Cidery Journal

... What is that big purple thing behind the kitchen?  Why it’s our new (used, actually) biodigester of course. This is a project that has been in the works for over a year and after a long wait for some critical upgrades, it finally arrived on site last week...

Biodigesting our Waste

Dec 1, 2019

What is that big purple thing behind the kitchen?  Why it’s our new (used, actually) biodigester of course. This is a project that has been in the works for over a year and after a long wait for some critical upgrades, it finally arrived on site last week...and so begins our effort to introduce this technology to Jefferson County as a potential solution for solid waste reduction and sustainable-energy production. 

Our Orchard property (formerly the Brown Dairy) is a fitting location for this experiment as most biodigesters operate on dairy farms—they serve to convert large amounts of otherwise noxious organic waste into a more useful fertilizer product while also producing methane gas which can be used to power equipment and machinery.  There are a number of complex biochemical reactions embedded in this process but in simplest terms the digester acts very much like a mechanical version of the digestive tract of a cow.  In goes food, out comes fertilizer and methane gas.  To further complicate things, the acronym used to describe this system is as a High solids Organic-waste Recycling System with Electrical output. Get it?

In our case, the foodstock will be a combination of food waste from our Cider Garden, from our commercial kitchen, and potentially from cider production (apple pomace and lees) as well as from the Chimacum schools, other local food service establishments, and local households.  We’ll grind that all into a slurry and feed it to the digester, which will in turn produce methane gas and a liquid “digestate.”  We plan to pump the methane gas over to the new Cider Barn to heat water for pasteurizing, cleaning, and heating the building itself.  We hope to package and sell the digestate as a fertilizer for local garderners.  Between reduced propane and electricity costs and income from digestate sales we hope to pay for the digester itself in a win-win proposition.  Less waste going into the local landfill, less money and resources spent on propane and electricity.

There are still a number of things that need to happen in multiple phases before it becomes fully operational.  We expect that over the next several months we’ll get electricity hooked up, get some “starter” from another biodigester on Whidbey Island so that we can get the biodigester functioning.  Then we’ll need to connect the methane line to the Cider Barn, and install some complicated plumbing that allows us to generate hot water and use it efficiently over there. 

Stay tuned for progress reports this spring!

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