METHOD FOR REMOVING CALCIUM FROM WATER CONCENTRATED IN CALCIUM BICARBONATE

PROBLEM TO BE SOLVED: To reduce calcium to the standard quality level of industrial water with simple chemical treatment by adding calcium hydroxide to a waste water concentrated in calcium as calcium bicarbonate to bring about reaction and fixing calcium to calcium carbonate which is removed. SOLUTION: When calcium is removed from a water concentrated in calcium bicarbonate, treating tanks 2 and 3 are arranged in parallel, and a waste water tank 1 is connected to the treating tank 2 through a flow controller 5. The waste water in the tank 1 is then introduced into the tank 2, and calcium hydroxide is added to the treating tank 2. The liq. overflowing the tank 2 is allowed to flow into the tank 3. A settling tank 4 is connected on the downstream side of the tank 3, the liq. overflowing the tank 3 is introduced into the settling tank 4, and solid is separated from liq. therein. The liq. overflowing the settling tank 4 is reutilized as a supernatant liq., and a slurry settled in the tank 4 and contg. solid is sent to a dehydration separator.