1. Introduction
In the countries of the European Union the technical policy in the field of utilization of sewage settlings of
urban wastewater becomes tougher every year. In the existing sewage treatment technologies, after
primary sedimentation tank, sewage settlings are surely formed. Also the excess activated sludge produced after
constructions of biological treatment. The volume of sediments which are formed in the course of sewage treatment
depending on the pollution concentration in waste liquid makes more than 0.5% of sewage volume [1, 2]. From the
economic point of view it is more expedient to use sediments in agriculture or to store them on separate sludge beds.
However, existence of a large number of pathogenic microorganisms, surface-active substances and ions of heavy
metals in sediments restrain their use in agriculture [3, 4]. In certain cases it is recommended to use various methods
of thermal processing (thermal drying, thermal aerobic and anaerobic stabilization, etc.) for the liquid and dewatered