We Started the Fire- with Biodigestion

At several points during our Island School journey, we experience many firsts. Only minutes ago, our biodigestion team went down in Bahamian history by producing and using the first biogas produced from an anaerobic digestion system. Just recently, we added a new system with 7% glycerol called “Hal-Drew,” named after a visiting master teacher and an Island School alum. Earlier this afternoon, we found this new addition to our digestion fleet to have several leaks in the gas tubing, disturbing the biogas production process. We quickly remedied this leaky situation by wrapping the holes in electrical tape. Our eyes lit up at the sight of the water level rising before we had even finished this process. An hour later, we returned to Hal-Drew to find that our patched-up machine had already produced an incredible amount of biogas. After observing it for a few minutes, we averaged the production rate to be 1.5 cm3 per minute. Some of our digesters don’t even produce this much after days of retention. In fact, we were surprised that this system with 7% glycerol produced any biogas at all; we were convinced based on previous readings that any digester with over 6% glycerol would be unstable and wouldn’t produce large amounts of biogas. Surprise, surprise! Not only did our 7% glycerol digester, Hal-Drew, produce gas, it made more than any of our other digesters. It was producing so quickly that we were even able to burn some of the stored gas and observe the flame. We were all overjoyed at the sight of our beloved buckets of pig poop slurry blossoming into a usable energy! Hopefully soon we can use this gas for our own benefit by roasting marshmallows as a Biodigestion team.

Hannah Twombly, Evan Wood, Eliza Hazen, Arben Ukperaj, Nicholas Elvinger, Sarah Becker