METHOD AND DEVICE FOR CONTROLLING AIR DIFFUSION RATE OF VARIABLE VOLUME BIOREACTOR

PURPOSE:To prevent the degradation in function by automatically adjusting an air diffusion rate in conformity with the fluctuation in a water level. CONSTITUTION:The raw water of org. waste water is introduced into a settling basin 15 and the supernatant liquid is introduced into a biotreatment reaction vessel after settling and separation. This waste water 5 flows upward and downward in a biomembrane fixed filter bed 2. An air diffusion pipe 3 is disposed in the lower part of the biomembrane fixed filter bed 2 and air is supplied from an aeration blower 4. The biooxidation treatment by an immersion filter bed method is executed in the part of the biomembrane fixed filter bed 2 under the water surface of the org. waste water the water level of which fluctuates upward and downward. A level gage 9 detects the rise of the water level upon rising of the water level. Then, a controller 11 calculates the deficient amt. of oxygen and increases the rotating speed of the aeration blower 4 via an inverter 12, thereby activating the aeration. The biotreatment is thereby stably executed and the energy consumption is reduced.