Notice of RetractionThe Effect of Air-Upflow Velocity on the Performance of Biological Aerated Filter

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Air-upflow velocity is a critical factor in the design and operation of the Biological Aerated Filter (BAFs)., in order to achieve optimal performance. The performance of a pilot-scale upflow biofilters filled with ceramsite in the municipal wastewater treatment was investigated over a wide range of air-upflow rates from 5.4 to 27 m/hr. Results from long-term operation of the BAF system indicate that the air-upflow velocity can affect the removal of pollutants, as well as the backwashing period. The growth of the air-upflow velocity improved the efficiency of the COD and NH₄⁺-N removal. But its growth is not always good for the TN removal when the air-upflow velocity was above 16.2 m/hr. SS removal rate deteriorated with the rising of the air upflow velocity, due to the air-scouring. The backwashing period enlarged from 24 to 48 hours as the air-upflow velocity increased from 5.4 to 27 m/hr. It was suggested the effective BAF controlled air-upflow velocity for pollutant removel and applicable back washing period is approximate 16.2 m/hr.