| 摘要 |
<p>PURPOSE:To obtain stable denitrification and dephoshorization performances by providing a means for adjusting the immersion depth of the screw of an aeration device which supplies and dissolves into liquid by utilizing the negative pressure generated at the front end of the screw as the screw rotates. CONSTITUTION:A rod 6 of driving device is contracted and the aeration device 2 is oscillated around a fulcrum shaft 4, then the immersion depth of the screw is set in a shallow position L1 and the air is dissolved into the treating liquid by the rotation of the screw at the time of aerating the liquid along with stirring. This rod 6 is then extended to change the immersion depth of the screw from the shallow position to a deep position at the time of anaerobically stirring the liquid without aerating the same. The aerobic stirring and the anaerobic stirring are alternately and repeatedly executed in an oxidation ditch by occasionally adjusting the immersion depth of the screw and controlling the rate of aeration in such a manner, by which the denitrification and dephoshorization of the treating liquid are stably executed.</p> |
