Positive draft aeration efficiently & effectively provides mechanical oxidation and gas removal
Positive draft aeration is accomplished in cylindrical or rectangular vessels where a counter-current flow of air and water is created. To increase contact surface area and exposure time, media is used in the form of loose fill of special shapes, easily cleaned PVC slats, or wood trays. Water is discharged into a tray at the top of the aerator that evenly distributes flow over the unit cross section with orifices or nozzles. It then drops into the aeration zone that contains the appropriate media and provides space for the air to move up through the finely dispersed water droplet.