| 摘要 |
<p>PURPOSE:To control DO variations even for an abrupt change in inflow sewage amt. by estimating the aeration amt. required at a point the sewage reaches the outlet of an aeration tank when variations in the inflow amt. of sewage in the aeration tank are detected and controlling the schedule of changes in air amt. predictively. CONSTITUTION:An aeration tank 1 is provided with PI control device having a DO meter 2 as detecting means at its beginning and an aeration amt. adjusting meter 4 as operating means at its end and with an inflow amt. variation detector 13 for sensing variations in the inflow amt. of sewage in the aeration tank. There are also provided an arrival time computing arithmetic unit 14 for computing the time required until variations in the inflow sewage amt. reach the mounting point of the DO meter 2, an air amt. multiplying memory device 11 for stable DO value and a required aeration amt. estimating device 15. In addition, there are provided an aeration amt. setting device 17 for determining a change in the air amt. so as to attain an estimated required air amt. computed by the air amt. multiplication after the arrival time computed by the aforesaid arithmetic unit 14 and an integral element arithmetic unit 12 for computing the correction amt. of the air flow.</p> |
