| 摘要 |
There are provided a process and apparatus for biologically treating an exhaust containing nitrides without requiring a large amount of water by treating a circulating water containing ammonia in the treating system, preferably by which clogging of the packed layers can be prevented. The first embodiment of the present invention relates to a process for treating an exhaust gas containing nitride by passing it through a microbial carrier packed layer while cyclically spraying circulating water thereon, which comprises nitrating the circulating water containing ammonia formed therein, reducing the nitrated water to effect denitrification, and cyclically using the resulting water as the circulating water. The process of the second embodiment of the present invention comprises dividing the microbial carrier packed layer into a former stage and a latter stage, carrying out the spray treatment of the former stage with a circulating water having a weak alkalinity of pH (8) to (9), mixing the circulating water withdrawn from the former stage with that from the later stage to form a circulating water having a pH of (6.0) to (8.0), and carrying out the denitrification treatment with the obtained circulating water.
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