Addition method of organic matter and flocculant in intermittent aeration type activated sludge method.

摘要

PURPOSE:To prevent the degradation in a phosphorus removing rate by installing an ORP meter to an aeration tank, measuring denitrification time in accordance with detection of an ORP flexure point to calculate a DN ratio and adding org. matter to the aeration tank at the point of the time the DN ratio attains a prescribed value or above. CONSTITUTION:The intermittent type activated sludge method comprises removing the nitrogen and phosphorus in waste water by repeating an aerobic state of executing aeration of the waste water and an anaerobic state of executing agitation by stopping aeration in two pieces of the aeration tanks 2a, 2b connected in series. The ORP meter 6a is installed to at least one aeration tank 2a and the measured output thereof is inputted to a controller 9. The operation is shifted into an agitating stage after the aeration is executed for the prescribed period of time. The denitrification time is measured by the controller 9 in accordance with the detection of the ORP flexure point and Tf/Te (DN ratio) is calculated. Consequently, the org. matter is added to the one aeration tank 2a by controlling an org. matter adding pump 11 by the controller 9 at the point of the time the DN ratio attains the prescribed value or above.