JPH05301092

PURPOSE:To simultaneously attain the outflow of suspended materials to fluorine-contg. waste water and the improvement in the rate of removing fluorine by passing ammonia fluoride-contg. water through a calcium carbonate- packed bed, then removing ammonium ions from the treated water and again passing the water through the calcium carbonate-packed bed. CONSTITUTION:The raw water past a raw water tank 1 is introduced into a first packed column 2 having the calcium carbonate-packed bed. The treated water from which fluorine is removed in this column enters an ammonia stripping column 3 where the water is aerated by an air suction blower 7. The ammonia in the treated water is dissolved in the form of MH4HCO3 and (NH4)2CO3 in the water and, therefore, the ammonia evaporates easily as gaseous NH3 when the water is aerated by gas, such as air. The treated water emitted from the ammonia stripping column 3 enters a second calcium carbonate-packed column 4 where the reaction of the calcium carbonate-packed material and the fluorine is again effected in the environment free from the disturbance of the ammonium ions.