| 摘要 |
PROBLEM TO BE SOLVED: To provide a pH reduction method for a secondary treated water of sewage which reduces the treatment cost for pH reduction of the secondary treated water, and improves safety in treatment operation therefor. SOLUTION: The secondary treated water of sewage is aerated with a carbon dioxide-containing gas, so that carbon dioxide in the gas is dissolved in the water. Thereby, the concentration of hydrogen ion (H<SP>+</SP>) in the secondary treated water of the sewage is increased to reduce the pH of the secondary treated water. As a result, the pH of the secondary treated water of the sewage can be reduced by the carbon dioxide-containing gas without using a pH adjuster such as sulfuric acid used in conventional methods, which enables reduction of the equipment cost for pH reduction treatment and of the running cost, and improves the safety of the treatment operation. COPYRIGHT: (C)2004,JPO&NCIPI
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