NATURAL WATER TREATMENT PROCESS Russian patent published in 2004 - IPC

FIELD: water treatment. SUBSTANCE: invention relates to water conditioning technology and can be used for treating natural waters, including sea water, to drinking standards. Treatment process comprises two stages of mechanical treatment, reverse-osmosis softening, and bactericidal treatment, the latter being accomplished by chlorination before mechanical treatment. Two mechanical treatment stages are followed by sodium sulfite dechlorination, after which water is cleaned by microfiltering and supplemented by inhibitor. Reverseosmosis softening is conducted in two steps, wherein, after the first one, concentrate is discarded and permeate is completed with inhibitor and sodium hydroxide to pH 10.4, Concentrate after the second reverse-osmosis step is admixed to stream entering the first reverse-osmosis step. To permeate is then added acid and it is passed through conditioning filters with calcium- magnesium charge. In addition, a part of permeate after the first reverseosmosis step may be passed to conditioning filter inlet and a part of permeate after the second reverse-osmosis step may be admixed to stream leaving conditioning filters. EFFECT: lowered investment expenses and expenses on maintenance of water desalting plants, reduced quality of treated water according to WHO recommendations, including those concerning boron and hardness salts. 3 cl, 2 dwg _