Influence of Air-Water Ratio on the N
2O Production in Biological Aerated Filter
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Graphical Abstract
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Abstract
Biological aerated filter (BAF) has been widely used in treatment of wastewater and reclaimed water. To date, little research has been done to control N 2O production in BAF. N 2O production from municipal wastewater at different air-water ratio of 9.8:1,5.0:1,2.5:1 respectively was investigated in biological aerated filter (BAF). The obtained results show that N -N and TN removal efficiency decreases with the decrease of air-water ratio. Under the condition of air-water ratio of 9.8:1,5.0:1,2.5:1, the percent of N 2O emission from BAF was 418.0306,247.9406,123.0638×10 -6, respectively, indicating that N 2O production in BAF can not be ignored. N 2O-N dissolved in the mixture at different air-water ratio increased first and then decreased along the filter layer, which was consistent with the variation of N -N concentration. Therefore, N 2O might be produced during nitrification. Considering nitrification efficiency, TN removal efficiency and N 2O emission control, the optimal air-water ratio is 5.0:1.
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