| 摘要 |
<p>PURPOSE:To effectively treat the waste wter obtained by stack gas desulfurization apparatus, by adjusting the pH of said waste water from the apparatus in which oxide or hydroxide of Mg, Ca are used as an absorbent, to 7-9, and performing solid-liquid sepn. thereafter executing solid-liquid separation through adjusting the pH of treated liquid to >=9.5. CONSTITUTION:Stack gas 1 containing sulfur oxide is led to an absorbing column 2 and desulfurized by bringing it into contact with absorbing liquid 3 that contains oxide or hydroxide or Mg, Ca. This waste water obtained by gas desulfurization is led to the first process which consists of a reaction tank 16 and a solid-liquid separation means 18. After adjusting the pH to 7-9 by adding acid or alkaline agent 17, it is separated into solid phase and liquid phase. The treated water is led to the second process which consists of a reaction tank 20 and a solid-liquid separation means 22. After making the pH to >=9.5 by adding an alkaline agent 21, it is separated into precipitate 23 and supernatant 24. The precipitate 23 is recovered as an absorbent and returned to the sulfur oxide absorption process and utilized effectively.</p> |
