| 摘要 |
Treatment of ammonia-comprising waste water comprises: (a) subjecting the waste water to a nitrification treatment using a nitrifying microorganism and adding oxygen, to give a solution comprising an oxidation product of ammonia, and (b) converting the oxidation product of ammonia into nitrogen using a denitrifying microorganism, use of bicarbonate-containing waste water, which is substantially stripped of bicarbonate by the supply of air, and maintaining the pH in the 1st step at /~7.2 by controlling the aeration, part of the ammonia present is converted into nitrite, and in the 2nd step the denitrifying microorganism uses the formed nitrite as oxidant for the remaining ammonia. In the 1st step, the waste water is fed to the nitrification reactor in an amount such that the reactor operates without sludge retention. The temperature is maintained at 25-60 deg C and the pH at 6-7.2. In the 2nd step, the temperature of the solution in the denitrification reactor is preferably maintained at 25-60 deg C and the pH at 6-9. Steps (a) and (b) may be carried out simultaneously in one bioreactor. The nitrifying and denitrifying microorganisms are present in a solid phase, the nitrifying microorganisms being substantially present in the outer, aerobic part of the solid phase and the denitrifying microorganisms being substantially present in the anaerobic, inner part of the solid phase.
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