Disinfection of Swimming Pool Water by UV Irradiation and Ozonation

Abstract
Description
The paper discusses the current trends in water disinfection technologies in the operation of swimming pools. Organic substances added to water by personnel or users, when interacting with a disinfectant, are transformed into disinfection by-products (DBPs), the toxicity of which is often unknown. Oxidative technologies are helpful to disinfect water, decrease the concentration of DBPs, and remove already formed compounds. Among the existing methods of water disinfection in swimming pools, the most effective methods are ultraviolet (UV) irradiation in combination with the technology of oxidation of organic compounds. This approach not only comprehensively disinfects the water in the pool but also limits the appearance of disinfection. In this work, we used ultraviolet disinfection of water together with ozonation. The UV dose was measured using a Tensor-31 radiometer. Colony-forming bacteria were controlled according to the requirements of SanPIN 2.1.2.1183-03. The experimental results showed that disinfection of water in the pool using prefiltration and UV irradiation does ensure inactivation of microorganisms, since the total microbial count and total coliforms CFU/cm3 exceed the permissible limits after 48 h. We developed an effective technology for disinfecting water in swimming pools, including an installation of combined action of UV irradiation and ozonation implemented by low-pressure lamps. The installation ensures the necessary irradiance of water at a level of >250 W/m2 and additional ozonation with a dose of ~0.1 g of introduced ozone per 1 m3 of water. Additional ozonation keeps the total microbial number below 24 CFU/cm3, and the residual ozone concentration in water did not exceed 0.015 mg/dm3. For a 75-m3 pool, two installations with a capacity of 8 m3/h ensure the bacteriological purity of water, yielding an irradiance of >250 W/m2 and injecting 0.1 g/m3 of ozone. The concentration of ozone in water does not exceed 0.015 mg/dm3.
Keywords
swimming pool water, water disinfection, UV-irradiation, combined UV-light and ozone
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