Abstract: A process for manufacturing a pasteurized substrate by biological decomposition of organic refuse is characterized by the following processing steps:a) A container (1) is half filled with a mixture of solid refuse to be decomposed, liquid substances are added, and the mixture is stirred for a first residence time of 2 to 3 hours.b) A quantity not greater than one-third of the weight of the mixed refuse of decanted clarified sludge at a temperature equal to that of the mixed refuse is added. A quantity of white lime may also be added, and stirring is continued for a further residence time of 69 to 70 hours. An apparatus for carrying out the process comprises a parallelepipedal container (1) with a pentagonal profile in the shape of an inverted house roof with its ridge pole sunk in the ground and whose width (b) is greater than its length (l). The base of the container includes two identical, obtuse-angled, mutually inclined half-bases (1.1, 1.