| 摘要 |
PURPOSE:To provide a method for treating a waste liquid by which an adequate amount of nitrate ion and ammonium ion is removed from the waste liquid and nitric acid and ammonium of high purity and high concentration are recovered at high recovery rate by desalting the waste liquid efficiently without lowering the concentration of electrolytes in the waste liquid as well as a waste liquid treatment device. CONSTITUTION:A waste liquid flows into an evaporation part after being heated by a heating part, and is concentrated by the process that moisture moves as a vapor through a hydrophobic membrane and is condensed by cooling water. Further, the concentrated waste liquid is sent to an electrolytic dialysis part 1 after being cooled by a refrigeration part, and is supplied to the desalinization chamber of each dialysis chamber 1A to 1C. If a voltage is applied to an anode 390 and a cathode 31, NO3-and NH4+ of the waste liquid migrate to an anode chamber 10 or a cathod chamber 12 through an anion exchange membrane 11 and a cation exchange membrane 13. Nitric acid is introduced from a nitric acid recovery system 18 into the anode chamber 10, and is returned to a nitric acid liquid tank 34 for circulation after absorbing NO3-. Aqueous ammonia is introduced from ammonia recovery system 19 into the cathode chamber 12, and is returned to an aqueous ammonia tank 20 for circulation after absorbing NH4+. |
