| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a sewage treating device capable of preventing the possibility that iron oxide film is formed by the nitrous nitrogen abundantly generated during the time until it is accustomed after it is installed at a prescribed place. SOLUTION: A septic tank is provided with a dephosphorization device P1 having an electrolytic cell 39, iron electrodes 40 and 41 and a direct current power source 42. The electrodes 40 and 41 elute by electrolysis the iron ion reacting with the phosphoric acid in the sewage. A nitrous nitrogen sensor 27 and a control part 20 are installed at the septic tank. The control part 20 makes the device to execute the dephosphorization treatment by flowing the water to be treated to the second flow passage for the first time when a nitrous nitrogen concn. becomes less than prescribed value after installing the septic tank at the prescribed place and starting sewage treating operation.</p> |
