METHOD FOR TREATING WATER CONTAINING FLUORIDE ION AND COD COMPONENT

摘要

PROBLEM TO BE SOLVED: To provide a method for treating water containing fluoride ions and COD components wherein water can be recovered so as to be utilized and fluoride ions and COD components can be removed efficiently at a high rate using a small amount of chemicals. SOLUTION: In a preliminary reaction tank 1, Ca salts and/or Al salts 7 are added to water 6 containing fluoride ions and COD components to adjust pH to 5-8 to effect sedimentation and solid-liquid separation is effected at a solid-liquid separation tank 2 to discharge sludge 11 and flowing out liquid 12 is evaporated at an evaporating device 3 to recover water 13 and concentrated liquid 14 is introduced into a coagulating reaction tank 4, where polyvalent metal salts 15 are added to the liquid 14 to adjust pH so that solids are produced and solid-liquid separation is effected in a solid-liquid separation tank 5 and sludge 20 is returned to the tank 1, while separated liquid is subjected to an ion-exchange treatment at an ion-exchange tank 22 filled with weak-base anion-exchange resins 23.