| 摘要 |
PURPOSE:To prevent the deterioration in properties of activated sludge and to prevent the deterioration of the quality of treated water by controlling the aeration time and the amt. to be aerated in accordance with the progress of the removal of BOD in a liquid mixed with sludge. CONSTITUTION:The specified time zones for each stage of inflow, aeration, settling, and discharge are set to the timer section 7a of a controller 7, and the operation is started. Waste water flows into a vessel 1, and a blower 3 is started at the specified time zone. The pH of the sludge-mixed liquid is reduced by nitration in the aeration stage. When the pH value reaches the set pH value too quickly, the settling stage is moved up. And when the amt. of air to be aerated is reduced or the pH value reaches the set pH value too late, the stages are successively moved down. After the discharge stage is finished, 40-60% of the sludge in the vessel is left in the vessel 1 for succeeding batch reaction, and waste water is freshly charged into the vessel 1. As the denitrification proceeds, a specified increase in pH is detected, and the aeration stage is started.
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