| 摘要 |
<p>PURPOSE:To obtain high purification efficiency under constantly stable condition, in an active sludge process, by calculating the most proper dissolved-oxygen concentration at a certain temperature on the basis of a measured temperature, and controlling a flow rate of aerating air. CONSTITUTION:Waste water having flowed through a waste water pipe 1 into a aeration vessel 2 is aerated by air fed from a blower 6 through an air-feed pipe 15, and then fed through an overflow pipe 16 into a precipitating vessel 3. A water thermometer 7 and a DC meter 8 are located inside the aeration vessel 2, and outputs from the meters are fed to a controller 12. In this case, the output from the water thermometer 7 is fed to an operator 11 which calculates an objective dissolved oxygen concentration at the said temperature in accordance with the formula undermentioned, and the calculation result is fed to the controller 12 to control the air-feed rate of the blower 6. The objective dissolved oxygen concentration DOT is obtained by the formula of DOT=K+0.125(30-T) ppm, wherein T is the temperature ( deg.C) of the water in the aeration vessel and K is a constant of 0.2-0.5.</p> |
