Russian experience in the use of chemical water treatment waste in economic activity: prospects for use in the treatment of sewage sludge (review article)

PURPOSE. To consider the experience of using chemical water treatment waste in economic activity. To analyze scientific publications of Russian and foreign authors in order to determine the most popular industries in this waste and information about projects already implemented in Russia and abroad. To provide a brief analysis of the main areas of processing and disposal of sewage sludge in the world and in Russia. To assess the prospects for the use of chemical water treatment waste in the treatment of sewage sludge.METHODS. To achieve this goal, an assessment of the environmental impact of chemical water treatment waste on the environmental situation and human health was carried out on the example of Kazan CHP-1 (KTEC-1). A number of studies of KTEC-1 carbonate sludge have been carried out to determine the granulometric and elemental composition. results. The physico-chemical composition of carbonate sludge depends on a number of parameters of the water treatment system at an energy facility: the process of liming and coagulation of water, the amount of insoluble salts, the dewatering technology used, etc. Carbonate sludge is insoluble in water, has a typical chemical composition containing calcium carbonate (CaCO3), calcium oxide (CaO), magnesium carbonate (MgCO3), magnesium oxide (MgO), iron hydroxide (Fe(OH)3), silicon dioxide (SiO2), etc.CONCLUSION. The use of this type of technological process makes it possible to reduce the amount of calcium oxide used and replace it with calcium oxide from carbonate sludge. The use of carbonate sludge as a sediment stabilizer due to the CaO content is confirmed by laboratory studies. Due to these data, the disposal of chemical water treatment waste is ensured, less pollution of environmental objects is achieved.