| 摘要 |
<p>PROBLEM TO BE SOLVED: To stably and accurately detect a water level of sewage in a aeration tank by providing plural pieces of electrodes for one water level detection enabling to detect the water level at a time coming contact with water, as a water level detection means for detecting the water level of sewage in the aeration tank provided with a separation membrane for filtering treating water. SOLUTION: The discharge water introduced into a septic tank passes through a precipitation separation tank 1, an anaerobic filter bed tank 2 and an aeration tank 3 and becomes aerobic by being fed air from a blower 7 connected with an air diffusing pipe 6, and treated with activated sludge, filtered with the separation membrane 9 and fed to a sterilizing tank 4. In this case, respectively a water level detection means 11 for detecting an upper and an lower limit water levels L1, L2 of the sewage is provided on the anaerobic filter bed tank 2 and a water level detecting means 12 for detecting the upper and the lower limit water levels L1, L2 is on the aeration tank 3. Each water level detection means 11, 12 consists of an electrode unit 15 provided with three pieces electrode bars longitudinally suspended, and only when the whole three electrode bars come into contact with the liquid, the water level is detected. Thus, an erroneous detection due to conduction, etc., caused by being stuck the electrode bar 16 with sludge, is prevented.</p> |
