| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently treat wastewater, such as flat panel display (FPD) manufacturing wastewater, containing organic acids such as phosphoric acid, nitric acid, and acetic acid while suppressing the amount of used chemical without causing trouble such as scale deposition by phosphoric acid-removing treatment using a calcium compound and subsequent RO membrane separation treatment. <P>SOLUTION: In a method for treating phosphoric acid-containing water, the calcium compound is added to the phosphoric acid-containing water, and the pH is adjusted to 6.5 or less. The precipitated apatite phosphate is solid-liquid separated, and the separated water is added with acid to adjust the pH to 5.5 or less, or is subjected to calcium-removing treatment, and then subjected to the RO membrane separation treatment. The RO membrane-concentrated water is further subjected to denitrification treatment. <P>COPYRIGHT: (C)2010,JPO&INPIT |
