| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a sewage treatment apparatus which dissolves oxygen in sludge in a sludge storage tank 28 and returns the sludge again to circulate it, and reduces the volume of the sludge by microorganism treatment in the sludge storage tank 28. <P>SOLUTION: Sludge transferred into the sludge storage tank 28 is transferred by a second sludge pump 30 into an oxygen dissolving device 34 through a flow regulating valve 32, and sludge in which oxygen has been dissolved by the oxygen dissolving device 34 is returned to the sludge storage tank 28 again to be circulated. A dissolved oxygen concentration meter 36 is installed in the sludge storage tank 28, and when the dissolved oxygen concentration in the sludge is 8 mg/L or less, the flow regulating valve 32 is fully opened to increase the amount of the circulating sludge, thereby activating microorganisms to promote the microorganism treatment. When the dissolved oxygen concentration is 8 mg/L or more, the flow regulating valve 32 is half opened to decrease the amount of the circulating sludge, thereby maintaining the dissolved oxygen concentration at an almost constant value to facilitate the microorganism treatment. The volume of the sludge in the sludge storage tank 28 is reduced by the microorganism treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
