| 摘要 |
Removal of nitrate from water comprises: (a) water passing downwards through a cation stage (1) with a weak cation exchanger (2) before passing upwards through an anion stage (3) which is separate from the cation stage (1), and with a strongly basic chloride form anion exchanger; (b) combined regeneration of the cation exchanger (2) to anion exchanger (4) or from anion exchanger (4) to cation exchanger (2), in which the cation exchanger (2) and the anion exchanger (4) are regenerated in downflow by acid, and the regeneration acid is fully consumed in the cation exchanger (2); (c) the regeneration acid is washed out in a number of stages, first in a cation exchanger (2) and anion exchanger (4) in a regeneration assembly (first washing stage), then by means of the anion exchanger (4) in the regeneration assembly (second washing stage), and then by the cation exchanger (2) and anion exchanger (4) in the operating direction (third washing stage). |
