Abstract: A method for composting decaying material by first treating the material to produce a decayable carbon/nitrogen ratio and continuously and countercurrently aerating the decaying material in a first step to produce a biologically active material and then introducing the biologically active material to a second step wherein it is discontinuously aerated at controlled intervals. The process produces a hygienically unobjectionable humus material in a continuous and industrially efficient manner.

Abstract: In the disclosed method, organic waste material of a water content of at least about 50% and a solid content of at least about 15% is biologically digested into compost. The organic waste material contains a flora of different species of microorganisms having different oxygen consumption requirements and different metabolism. The organic waste material is introduced into an aerating reactor with top inlet and bottom discharge so as to form an air permeable material column in the reactor. Air, which may be enriched with oxygen, is blown through the column in an upward direction without mechanical agitation of the column. Since the flora of microorganism species present in the material has different oxygen consumption requirements and different metabolism, the air flow is controlled in such a way that the microorganisms can settle at distinct levels within the reactor space where the environmental conditions are most favorable.