Modern approaches to treatment and recovery of secondary sludge of domestic sewage

For today, pollution of the environment, in particular of surface waters, has led to an environmental crisis in many countries of the world. One of the reasons for this is the use of outdated approaches to the treatment and recovery of sewage sludge. The article presents the results of the study of literary sources in order to analyze the proposals for the treatment of secondary sludge of domestic sewage in different countries. To neutralize sewage sludge, scientists consider the possibility of obtaining fertilizes under conditions of biosulfidogenesis during the dissimilation recovery of poorly soluble sulfates or the use of enhanced oxidation technology. A new concept of domestic sewage treatment has also been proposed, which can solve the issue of sewage sludge control at the place of its forming. The main areas of sustainable sludge control are its use in agriculture as fertilizer and for the reclamation of devastated or degraded lands, as well as energy recovery by burning and alternative thermal methods such as pyrolysis, quasi-pyrolysis and gasification. It was established that the applicability of this or that technology of sewage sludge recovery depends on many local factors, in particular: productivity of sewage station; composition and methods of sewage treatment and its sediments; efficiency of sewage treatment plants; climatic zone of the sewage system location; availability of energy and material resources, etc. Today, it is relevant to monitor the qualitative composition of sewage sludge, as well as soils and natural waters regarding pollutants that can be detected in the sewage of the corresponding settlement, in order to make operational decisions to control environmental risks, as well as conduct scientific research to improve recycling and recovery technologies for sewage sludge of various composition in agricultural systems, which will help to protect the environment against pollution and rational use of land.