(EN) A method is suggested for minimizing biological sludge in which biologically formed sludges are broken by disintegration wihtin the scope of a biological sludge treatment. The disintegrated sludge is subjected to a phase separation -- preferably a flotation - before it is fed into the biological sludge reactor, so that the treatment volume of the subsequent sludge treatment devices can be reduced. During disintegration of the biologically formed sludge, the cell walls of the microorganisms that form the organic part of the sludge are destroyed mechanically. Up to now, these microorganisms have passed the biological sludge treatment largely undamaged and form the high organic part of dry substance of up to 50% of the mass of solid substance. The broken cell components are mineralized to biogas by organisms of the biological sludge treatment, preferably under anaerobic conditions. The dry sustance of the sludge is reduced to the mineral fractions, the water binding property is reduced, whereby the outflow of free water is promoted and, thus, the sludge volume to be disposed is drastically reduced.
