| 摘要 |
<p>A method for removal of ammonia and ammonium salts from industrial waste water comprises the steps of passing the water through distillation columns (1, 2) in countercurrent to steam or preheated air, and at an intermediate stage (6) adding alkali (e.g. milk of lime) in order to convert ammonium ions to ammonia. The distillation column (2) before the addition of the alkali has a fresh supply (10) of steam or preheated air, different from that (9) of the distillation column (1) after the addition of alkali. The distillation before the alkali addition is such as to remove substantially all carbonic acid, in order to reduce the amount of alkali required and to avoid the formation of scale. <IMAGE></p> |
