Enhancement of Nitrogen Removal Performance in Three-Stage Biological Aerated Filter System with Change in the Flow Path

摘要

In this study, we propose a three-stage BAF process, within which both nitrification and denitrification phases were incorporated. It has two-step cycle and each step was carried out in sequence by changing the flow directions with the recirculation of nitrified wastewater. Based on the experimental tests, the proposed system was very effective on nitrification and denitrification at low influent TCOD to T-N ratio, compared with other conventional BAF systems. It was revealed that the system can minimize the organic loss and maximize the better use of bio-sorbed organics for the denitrification reaction.Overall, nitrogen removal performance was enhanced by changing flow direction of influent,recirculating nitrified wastewater, employing three functional columns with roles of sorption (in step 2:denitrification), denitrification (in step 2: sorption), and nitrification, respectively.