Purifying waste water, esp. from dye synthesis - by ozonisation at alkaline pH, blowing through air at acid pH, and pptn. with alkaline earth salt

摘要

Waste water is purified by (a) treating the water at alkaline pH with O3 in countercurrent, followed by (b) adjusting the pH of the water to acid and blowing air through the soln., and/or (c) adding alkaline earth metal salts to the water to pH below 7 and filtering. Stages (a), (b) and/or (c) may be repeated. The pH is (a) 10-13.5, (b) 3-4, (c) 5.5-6.5. Stages (a), (b) and (c) are carried out 2-5 (3) times, or stage (a) may be carried out alone, opt. with irradiation with UV light, esp. with emission max. of 254 nm. (c) The alkaline earth cpd. is a cpd. of Ca, esp. CaCl2 or Ca(OH)2. USE/ADVANTAGE - The water may contain phenols, aromatics, amines, chloro-hydrocarbons, sulphonic acids and heterocycles, esp. cpds. obtd. in synthesis of dyes. Harmful organic matter is largely broken down.