BIOLOGICAL REMOVAL METHOD OF ORGANIC MATERIAL AND NUTRIENT SALT FOR WASTEWATER TREATMENT AND APPARATUS THEREFOR

摘要

PURPOSE: Provided are a biological removal method of organic material and nutrient salt for wastewater treatment and an apparatus therefor without being influenced by water temperature change by selective operating a third aeration tank (33) according to seasonal water temperature. In case of the wastewater temperature is below 18deg.C, the third aeration tank (33) is switched to continuous aeration mode so that nitrification/phosphate uptake rate is maintained stably. In case of the wastewater temperature is above 19deg.C, the third aeration tank (33) is switched to intermittent aeration mode (aeration for only 20min/hour) so that excess nitrification and sludge bulking is prevented. CONSTITUTION: The shown apparatus comprises following devices: a grit chamber (10) equipping a screen in the front part; a flow-equalization tank (20) for controlling inflow loading; an aeration part (30) having several sub-aeration tanks therein; and a final settling tank (40) for overflowing supernatant and settling microorganism. The aeration tank (30) comprises a first aeration tank (31), a second aeration tank (32), a third aeration tank (33), and a continuous-aeration tank (34). The first, second, and third aeration tanks (31)(32)(33) are aerated for 20 minutes and stationed for 40 minutes.