Richard Nelson came up with this idea when he was sent by Canadian National Research Councel to NASA in 1992 for his SolaRoof invention that we are developing into various commercialized products. Beside getting biogas (now we call it PyraGAS), you can both liquid form (compost tea) and solid form (mainly organic fiber) of organic fertilizer. Easy to build and zero effort to maintain as it works only by a small water pump and a timer. I am going to build one and place it inside my PyraPOD4 Grande-17 in the backyard.
A story about Richard Nelson and his simple and yet unprecedented inventions