So I came across a cool anaerobic digester design when looking at the Biogas solutions Uganda web page. Its a floating drum digester that requires a feed volume of 3000L, with 1500 kg of cow dung and 1500 L of water mixed in. It only takes a day to install and requires feeding morning and night but it seems that people adopting this design can throw in any food waste or crop residues also. Check it out in the link below