PREDICTION OF RADIOACTIVE COMPOUND SEDIMENTATION FROM DEACTIVATION STATION WASTEWATER IN URBAN SEWERAGE SYSTEMS

Problem. Under current conditions of urban wastewater management, the issue of safe discharge of effluents containing radioactive substances is of particular relevance. The risk of forming insoluble radioactive sediments in sewer pipes remains unresolved, which could lead to accumulation, operational difficulties, and a significant increase in environmental hazards at such industrial facilities.Objective. To assess the probability of sedimentation of radioactive compounds from the industrial wastewater of a deactivation station upon discharge into urban sewer systems. To assess the probability of insoluble compound formation and subsequent sedimentation in urban sewerage networks, arising from the interaction of radionuclides in deactivation station wastewater with components of urban wastewater.Research Methods. Hydrochemical analysis, gamma spectrometry for measuring radionuclide activity, and specially developed software for converting radionuclide activity to mass concentration were used. Calculations were carried out based on sedimentation equilibrium considering the chemical properties of the substances.Main Results. It was found that most radioactive substances (Ra-226, Th-232) present in the wastewater of the deactivation station precipitate at the stage of local treatment in a sump, especially when coagulants are applied. Iodine-131 and other water-soluble isotopes (K-40, Cs-137) do not precipitate under urban sewer conditions. Calculations confirmed that the residual radionuclide concentrations are significantly lower than the threshold levels required for sediment formation, including in reactions with hydrogen sulfide.Conclusions and Author’s Proposals. It is proven that by adhering to established technological standards"and the use of coagulation, the risk of radioactive compound sedimentation in urban sewer systems is eliminated. It is recommended to implement similar monitoring and treatment systems at other radiation-hazardous industrial facilities.