The invention relates to a method and device for the wet-mechanical treatment of a substance mixture, particularly of refuse of all types, comprised of inert substances, water and of organic substances having a water-soluble and bioconvertible portion, whereby water is used as a solvent, washing agent and separating agent. According to the invention: the substance mixture, with a set dry substance content of 15-25%, is firstly mixed; afterwards, a first inert heavy fraction with a particle size of >25 mm and a first organic light fraction with a particle size of 30-120 mm are subsequently separated out in a first stage with a dry substance content of 10-20%; in a second stage with a dry substance content of 6-12%, a second inert heavy fraction with a particle size of 3-30 mm separated out by gravity, and a second organic light fraction with a particle size of 3-30 mm is separated out by sieving and rinsing, and finally; in a third stage with a dry substance content of 3-8%, a third inert heavy fraction with a particle size <2 mm is separated out by centrifugal forces, and a third organic light fraction with a particle size of 150 ?m-3 mm is separated out by sieving and rinsing.