| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a method and an apparatus for treating the water containing inorganic-state nitrogen or phosphorus, in each of which nitrate nitrogen and nitrite nitrogen are removed/reduced by sulfur denitrification being a biological reaction, phosphoric acid and ammonia nitrogen are also reduced easily at the same time by the action of magnesium hydroxide and recovered for fertilizer etc. and the magnesium hydroxide is washed with citric acid so that the effect of magnesium hydroxide can be exhibited surely over a long period of time. <P>SOLUTION: The water containing inorganic-state nitrogen and phosphorus is made to pass through a single reaction tank 1 packed with a material 2 consisting of sulfur, calcium carbonate, magnesium hydroxide and, if necessary, a vermiculite-purified stone so that the inorganic-state nitrogen is removed/reduced and the phosphorus is recovered as magnesium ammonium phosphate or calcium phosphate. A magnesium hydroxide reaction tank is arranged for exhibiting the effect of the magnesium hydroxide surely over a long period of time so that the magnesium hydroxide is washed with citric acid in the magnesium hydroxide reaction tank. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
