| 摘要 |
PROBLEM TO BE SOLVED: To prevent a large amount of carbonate ions and bicarbonate ions from remaining in treated water, to sufficiently perform treatment using a pH meter and slight incidental equipment thereof and to reduce equipment cost and operation cost. SOLUTION: The treatment apparatus for calcium-containing wastewater has front stage addition means 1, 3 and 10 for adding sodium hydrooxide to calcium-containing wastewater on the basis of the pH thereof until first pH is obtained and rear stage addition means 2, 3 and 11, and 4 and 12 for adjusting the pH of the wastewater to 9.2-9.8 by calculating the concentrations of bicarbonate ions and free carbonic acid in the wastewater on the basis of the amount of sodium hydroxide added and the pH of the wastewater, adding sodium hydroxide corresponding to the total amount of them to substitute the bicarbonate ions and free carbonic acid in the raw water with carbonate ions being the reactive group with calcium, and adding sodium carbonate at the same time.
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