Abstract: A process includes the steps of: introducing, in a sequential manner and at a predetermined frequency, a substrate of organic waste substances by loading from above inside at least one cylindrical container of circular, polygonal or other cross-section having a vertical axis and at least one transverse horizontal dimension of which is small, in other words of the order of 1 m or even less, the vertical walls of which are at least partially made from a non-gastight material, such as a porous or aerated material; introducing into this pile or windrow lumbricids which will climb upwards; withdrawing, in a sequential manner and at a predetermined frequency, the lower substrate layer of previously lumbricid-composted organic material, this withdrawal causing the substrate to be lowered sequentially, under gravity, at a speed at most equal to that at which the lumbricids climb; and, removing the substrate of previously lumbricid-composted organic material.