Anaerobic Digestion

Anaerobic Digestion

STI has recently started a research experiment with a two stage anaerobic digester. We constructed the digester out of two 58 gallon poly barrels and we are currently using a small domestic water heater to maintain the optimum temperature of 95 degrees for methanogenic bacteria formation.

So what the point of all of this? The point is that 30% of what goes into our landfills is organic waste that could have been composted or anaerobically digested. And the benefits of digestion? Well here are a few:

The end product is a tea fertilizer containing five times more nitrogen than regular compost; the tea is to be used in our subterranean planter garden
Some items that are not usually aerobically composted can be safely digested; this includes meats, vegetable oil, fats, etc.
By maintaining a high temperature in the digester tank, methanogenic bacteria thrive and consume waste to make biogas; Biogas can be burned as cooking fuel, or even used to run a generator

Getting the right bacteria growing in the beginning is the hard part. We used inoculate from a local pond. This is the sludge off the bottom, where the little methanogenic bacteria live. We added around three gallons of this sludge to the first digester tank. It is our hope that through feeding just a little feedstock each day- that we can grow our ecosystem into one that will produce a large volume of biogas and fertilizer tea.

More to come soon…