RU2203511C2 - Method for cleaning water reservoir from radioactive isotopes - Google Patents

Abstract

FIELD: decontaminating water systems (rivers, ponds, lakes, and storage pools). SUBSTANCE: method used for cleaning natural water reservoirs from radioactive isotopes of strontium 90, 89 and cesium 137 involves covering of water reservoir surface with natural sorbent during freezing-over period. Natural sorbent used for the purpose is glauconitic sand. Then during next freezing-over period reservoir surface is covered with clay, and these operations are repeated until reservoir water is cleaned up to degree complying with maximum admissible concentration. EFFECT: facilitated procedure, reduced cost, enhanced reliability of water decontamination.

Description

 The invention relates to the purification of a natural reservoir of radioactive isotopes of strontium 90, 89 and cesium 137 and can be used for decontamination of water from water systems (rivers, ponds, lakes, reservoirs).

 A known method of purifying water in natural reservoirs by introducing into the reservoir a natural sorbent, the reserves of which in Russia and the CIS countries are quite large (RF application 94038576, G 21 F 9/12 "Method of water purification", published on 09/10/96).

 The disadvantage of this method of water purification is the uncertainty of the proposed solution, its lack of development, the absence of a specific technical solution.

 There is also a known method of water purification, selected as a prototype, including its deactivation by introducing natural or artificially created sorbents onto the surface of a reservoir using their sorption and ion-exchange properties (RF application 94041058, G 21 F 9/12 "Water purification method", published on September 20, 1996).

 The disadvantage of the prototype is also that there is no specific technical solution, the sorbents that can be used to perform this task are not indicated.

 The challenge facing the inventors was to create a simple, inexpensive, reliable way to decontaminate water in contaminated water bodies from radioactive isotopes from radioactive contamination.

 A method is proposed for purifying water in a natural reservoir contaminated with radioactive isotopes from radioactive contamination by introducing a natural sorbent onto the surface of the reservoir, the new one being that glauconite sand is used as the sorbent, which is introduced during the period of freezing, then the surface of the reservoir is covered with a layer in the subsequent period of freezing. clay, repeating these operations until the degree of purification of water in the reservoir, corresponding to the maximum permissible concentration (MPC).

Tests of the proposed method, conducted in laboratories and in natural conditions on the Techa River, contaminated with radionuclides of strontium 90, 89 and cesium 137 as a result of the accident at the Mayak association, showed that the use of a natural sorbent - glauconite sand (K, Na) (Fe, Al , Mg) ₂ (SiAl) ₄ O ₁₀ (OH) _2, which is a common natural mineral in the various areas of Russia, including Chelyabinsk, Ryazan, Moscow and other areas having sorptive and ion exchange properties to radioactive isotopes, is about optimality option for treatment of water contaminated by radionuclides reservoirs and making it in consecutive seasons for the clay as it were the burial of the sand from the extraction of the radionuclides under a layer of clay, the repetition of these operations to achieve MACs of radionuclides in water provides a simple cost effective way to solve the problem.

 When conducting a search on patent and scientific and technical information, no solutions were found containing the totality of the proposed features, which allows us to conclude that the criteria of "novelty" and "inventive step" are met.

 The proposed method is as follows.

 During freeze-up, a layer of 30-50 cm of glauconite sand is applied to the surface of a reservoir contaminated with radioactive isotopes, for example, strontium 90, 89, cesium 137, by any known method. During melting ice, glauconite sand falls to the bottom of the reservoir and, by ion exchange and sorption, extracts radionuclides from silt and water. In the subsequent period of ice formation, a clay layer of 50-70 cm is similarly applied to the surface of the reservoir, and it, in turn, immerses at the bottom of the reservoir, covering the layer of glauconite sand with radionuclides extracted into it. In subsequent years, if necessary (analyzes of water for the presence of radionuclides in it), these operations are repeated until the degree of water purification in the reservoir corresponding to the MPC is reached.

 Example. With a bulldozer, the surface of the river 1 km long in winter is covered with a layer of glauconite sand 50 cm thick, leveled. In spring, sand falls to the bottom of the reservoir, closing silt and extracting radioactive isotopes from it and water during the year. Next winter, a clay layer with a thickness of 50 cm is applied to the ice with a bulldozer. Water is analyzed for the presence of radioactive isotopes and, if present, in quantities exceeding the MPC, again in winter the surface of the reservoir is covered with glauconite sand, and in the next season, clay and so on, until water tests show compliance with the MPC.

 The proposed method is simple, cost-effective, allows you to use common minerals throughout the country - glauconite sand, clay, while ensuring reliable purification of water from radionuclides.

Claims (1)

 A method of purifying water in a natural reservoir contaminated with radioactive isotopes from radioactive contamination by introducing a natural sorbent onto the surface of the reservoir, characterized in that glauconite sand is used as the sorbent, which is introduced during the ice-freezing period, then in the subsequent ice-freeing period the surface of the reservoir is covered with a clay layer, repeating these operations to achieve the degree of water purification in the reservoir corresponding to the maximum permissible concentration.