Wet treatment of denitration and desulfurization waste liquid

Abstract

Abstract PURPOSE: To make waste water disposable by a method wherein waste liquid is filtered after alkali treatment and an inorg. coagulating agent containing Al ion to the filtrate to coagulate and precipitate amine type nitrogen compound ions at a specific pH or more. CONSTITUTION: Raw waste liquid is received in a step 2 and SS is precipitated naturally as well as maintaining the pH of the waste liquid at about neutral point by Ca(OH) 2 to precipitate Fe 3+ or Cr 3+ . A pH of a supernatant liquid in the step 2 is moreover raised in a step 3 to precipitate almost all metal ions and SO 4 2- . Subsequently, in a step 4 for coagulating and precipitating amine type nitrogen compound ions, an inorg. coagulating agent containing Al ion is added to the treated waste liquid of the step 3 and, moreover, an alkaline agent is added to raise the pH to 10 or more to remove a considerable portion of amine type nitrogen compounds and fluorine. In this case, S 2 O 6 2- is also removed efficiently. The precipitate is subjected to heat treatment to be made disposable. The waste liquid of the step 4 is neutralized and filtered and, after COD is adjusted, discharged. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Koichi Shigeta
• 👤 Yoshio Hamao

Bibliographic Details