So 'scuse me for mentioning it but Afrigadget's latest story has come up with a neat way of turning chicken sh1t into chicken salad – otherwise known as a DIY methane digester. It reports that "David from Kenya" has made a digester that works mainly on "livestock faeces". It is made from an old oil drum.
The balloon shows that gas is being produced. The costs for the drum and professional valves may already be too high for some, and the design isn't that optimal. They intend to add a storage drum with a water-filled header tank for constant pressure and the loading & desludging processes obviously still require some work.
He shovels the "faeces" in there and the resulting gas is carefully kept under constant pressure so it can be used for cooking or lighting.The trick is the pressure mechanism. When the digester produces methane, a balloon is puffed up. The Digester needs a storage drum and a water-filled header tank to maintain constant pressure through the entire process.
David is also working on the "loading and desludging" process (otherwise known as shovelling s**t) to make his digester more efficient. But you can read all about it here.
VIA OffGrid
For domestic biogas digesters, with floating dome storage tank, see… http://solarcities.blogspot.com/