TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: Before the step of displacing air, the temperature of the vessel contents is 15-75 degrees Celsius, or raised to 15-75 (preferably at least 50 degrees Celsius) by subjecting the vessel contents to conditions under which aerobic composting of the vessel contents will proceed. Air is introduced to the vessel contents at 1-1000 (preferably approximately 25 kPa) above atmospheric pressure to ensure even penetration of the vessel contents by air before the step of displacing air. Water is added to the vessel contents to adjust the moisture content of the vessel contents to 40-60 % wet weight (w/w) also before the step of displacing air. Oxygen in the vessel is depleted after the temperature of the contents has been allowed to rise to 15-75 (preferably at least 50 degrees Celsius) before the step of displacing air. An anaerobic bacterial inoculum is added to the vessel contents to facilitate anaerobic digestion of the contents at 15-75 degrees Celsius. Air is introduced to the residues at 1-1000 (preferably approximately 25 kPa) above atmospheric pressure to ensure even penetration of the residues by air, and thus to facilitate aerobic composting of the residues. The portion of water removed from the vessel results in moisture content of the residues of 40-60 % wet weight (w/w).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Product: The gaseous byproducts separated from the residues include methane. The formed compost is aerobically stable. EXAMPLE - Shredded newspaper (6.75 kg), shredded cardboard (6.75 kg), grass clippings (4.4 kg), garden waste (30.4 kg), and chicken manure (38.3 kg) were placed in a vessel. The carbon:nitrogen ratio of the waste material was 25.6. Air (300 L/hr) was fed to the vessel contents and vessel interior air pressure was kept at 25 kPa above atmospheric pressure. The vessel contents temperature rose to 52 degrees Celsius after 3 days, and air flow was stopped. Liquid digestate recirculation through the vessel was done for 8 days. The biogas production during the anaerobic digestion was 7 m power 3/m power 3/day and the biogas methane content was 40-60%. After the anaerobic digestion, the liquid digestate was drained from the vessel and air (150 L/hr) was fed to the vessel. The vessel interior air pressure was kept at 25 kPa above atmospheric pressure. After 5 days, the formed compost was removed from the vessel. The compost internal temperatures did not exceed 24 degrees Celsius for another four consecutive days.