Aeration Equipment and Air blowers

Aeration equipment and air blowers are used to provide aeration air (for biological degradation of the organic components in the wastewater.) 

Inflow to the tank is normally interrupted during decantation, and hence, partitions may be made in the tank to continue the process and mixed liquor suspended solids shall not be washed out with the treated effluent. As a result, the total process cycle time can be reduced. 

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Mechanical Cells. Figure 19-73 presents a schematic representation of a typical mechanical device commonly known as a flotation cell. It is characterized by a cubic or cylindrical shape, equipped with an impeller surrounded by baffles with provisions for introduction of the feed slurry and removal of froth overflow and tailings underflow. The machines receive the supply of air through a concentric pipe surrounding the impeller shaft, either by self-aeration due to the pressure drop created by the rotating impeller or by air injection by means of an external blower. In a typical installation, a number of flotation cells are connected in series such that each cell outputs froth into a launder and the underflow from one cell goes to the next one. The cell design may be such that the flow of slurry from one cell to another can either be restricted by weirs or unrestricted. 

The aeration is produced by diffusion through the pipes that transport the air to four horizontal mbes submerged in the reactor. Three blowers of between 75 and 110 kW inject the air into the sludge or mixture when this is being recycled, just before it returns to the bioreactor. To obtain correct aeration, the bioreactor has an automated system for recording and controlling the quantity of dissolved oxygen that is present in the mixmre at each moment. The bioreactor is also equipped with meters to continuously monitor the level and pH. 

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