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On May 3, 2011 the inoculation of the manure/glycerine mixture happened for all of our digesters. Our original four digesters, Sam, Jake, Dave and Taylor, have now been replenished three times, and the new addition to biodigester family, Haldrew, has received its second filling. We also spent time constructing our next two digesters, which will contain a mixture of 9% and 11% glycerol, respectively, but we’re saving their inoculation for class on Thursday so that their seals can set properly. Ample drying time is crucial to the sealing process—it maintains the anaerobic environment that we need to make biogas.
When done correctly, the inoculation task can be done fast and efficiently. The process involves collecting pig waste from the farm, weighing it, mixing it with water to create a homogenous slurry, and then adding varying amounts of glycerine to each digester. Our original five digesters have been given the breath of life from the manure that now fills its tanks. The two new digesters, named Slarzben and Hicvan (a combination of the names of the biodigestion team), will be coming online at the end of the week.
We’re not really sure what the results of these new additions will be—hopefully lots of gas production! Soon enough we will have seven digester models working to produce biogas for our experiment that will affect the mixtures we use for the biodigester being built for the Island School, which will hold the communities waste after it has been processed in the Poo-Poo Gardens. This is exciting because biogas has already been in almost every the digester. Only time will tell which digesters will work the best; we’ll use the results of this experiment as a model for our larger scale digester.
-Arben Ukperaj