| 摘要 |
<p>PURPOSE:To enhance the efficiency in removing nitrogen by providing a supernatant liquid separation means at the top part of a biological sewage treating vessel, and an untreated water introducing means and a means for intermittently introducing air at the bottom part. CONSTITUTION:The treating vessel 12 of a biological sewage treating apparatus S is separated by a porous plate 15 into a lower carrier-packed chamber 13 and an upper supernatant liquid chamber 14. Besides, a line 18 is provided introducing a circulating liquid taken out from the upper supernatant liquid chamber 14 into a liquid receiving part 21. Consequently, since untreated water is repeatedly nitrated and denitrified, treated water can be obtained with extremely high denitrification efficiency.</p> |
