| 摘要 |
<p>PROBLEM TO BE SOLVED: To remove nitrogen oxide ions and ammoniacal nitrogen by a simple operation by a method wherein waste water containing nitric acid nitrogen or nitrous acid nitrogen and phosphorus is brought into contact with iron to effect reaction and alkali is added to the reaction liquid to adjust the pH of the liquid to a specific value and gas is blown into the liquid to remove ammonia. SOLUTION: When nitrogen and phosphorus are removed from waste water, at first, nitrate ions and nitrite ions contained in waste water to be treated are brought into contact with iron to reduce the ions to nitrogen gas or ammonium ions. Next, alkali is added to the reaction liquid to adjust pH value thereof to 9-14 and gas is then blown into the liquid to remove ammonia so as to be carried by the gas. For treating ammonia in exhaust gas containing the ammonia, the gas is brought into contact with sulfuric acid solution to absorb and recover ammonia or the ammonia is burned or catalytically oxidized. And since ionized iron reacts with phosphorus components to form salt which cannot be easily dissolved, by removing the iron, phosphorus in the water to be treated can be removed.</p> |
