[Digestion] "design for stirring

[Michael Smith]

 I am stuck in the design for a small scale digester. ( small farm/home). I envision a tank similar to a propane tank (8' to 11' long ) with some kind of pedal stirrer design either manual or motorized when necessary. Paddles like multiple pedals that would mix not agitate. A design that would have these paddles attached to a shaft that would protrude out one end of the tank to either attach a motor PTO or a stand-up bike pedal to manually do a little churning. Has anyone done this?