PREVENTING METHOD FOR RED WATER IN CITY WATER

摘要

PURPOSE: To prevent generation of red water by a comparatively miniature equipment by mixing water containing free carbonic acid with slurry of calcium carbonate or calcium hydroxide under pressure, and thereafter injecting a prescribed quantity of the produced calcium hydrogen carbonate aqueous solution and a prescribed quantity of a slaked line aqueous solution to city water and improving Langeria index. ;CONSTITUTION: A preventing method for red water in city water is constituted as follows. Slurry of calcium carbonate or calcium hydroxide is produced in a slurry tank 1. Water containing free carbonic acid is produced under pressure in a dissolver 5 for pressurizing gaseous carbon dioxide. Slurry and water containing free carbonic acid are sent to a mixer 3 at the rate sufficient to convert the calcium component of slurry into calcium hydrogen carbonate and mixed. The mixture is set to a production tank 4 for calcium hydrogen carbonate and a calcium hydrogen carbonate aqueous solution is produced in the production tank. The aqueous solution is injected to city water in a treatment tank 6 at such quantity that calcium hardness of city water is regulated to ≥40ppm. Furthermore a slaked lime aqueous solution is injected to city water in the treatment tank 6 at such quantity that pH of city water is regulated to 8.0-8.5. Thereby Langeria index is improved.;COPYRIGHT: (C)1993,JPO&Japio