| 摘要 |
PURPOSE:To efficiently concentrate a waste solution containing tetraalkylammonium hydroxide used as an analytical reagent or an alkali solvent and to obtain treated water with good quality, by adjusting the pH of said waste solution to 9-12 while supplying the pH adjusted waste solution to a reverse osmosis membrane apparatus under pressure. CONSTITUTION:The pH of a waste solution containing tetraalkylammonium hydroxide is adjusted to 9-12 while the pH adjusted waste solution is passed through a security filter 5 to remove the suspended substance therein and subsequently pressurized corresponding to the concn. of salts by a pump 6 to be supplied to a reverse osmosis membrane apparatus. Tetraalkylammonium hydroxide in the waste solution is excluded by the membrane and the transmitted water is discharged from pipes 7, 7' in extremely good water quality. The concentrate from reverse osmosis membrane apparatuses 3, 3' is returned to a raw water line through concentrate pipes 9, 9' and a recirculation pipe 10 and recirculated while a part thereof is recovered in a tank 8 as a concentrate.
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