Abstract: Apparatus (10) for anaerobic digestion of organic waste, comprises a reaction chamber (12) and a gas pressure regulator (14). The reaction chamber (12) comprises a first cell (20) and a second cell (22) linked by a passageway (24) for flow of organic waste slurry from a lower or bottom region of one cell to a lower or bottom region of another cell. The second cell is configured to retain gas under pressure in order to displace organic waste slurry through the passageway (24) from the second cell (22) to the first cell (20) in order to build a head of organic waste slurry in the first cell (20). The gas pressure regulator (14) is configured to release pressurized gas from the second cell in order to discharge the head of organic waste slurry from the first cell (20) back to the second cell (22) and agitate organic waste slurry in the reaction chamber (12).

Abstract: A method of anaerobically digesting organic material, comprising: providing a reaction chamber (12) comprising first and second cells (20,22) linked by a passageway (24) for flow of organic waste slurry from a bottom region of one cell to a bottom region of another cell; placing an organic waste slurry (S) in the reaction chamber (12) to fill at least the bottom region of each cell; displacing organic waste slurry (S) through the passageway (24) from the first cell (20) to the second cell (22) to build a head ?h of organic waste slurry (S) in the second cell (22); and discharging the head ?h of organic waste slurry (S) from the second cell (22) to agitate organic waste slurry in the reaction chamber (12).