后置反硝化BAF除污效能的主要影响因素研究

Influence of External Carbon Source Dosage and Hydraulic Loading on Pollutants Removal by Post-denitrification Biological Aerated Filter

通过实验室模拟,考察了后置反硝化曝气生物滤池(BAF)工艺对污水厂尾水的脱氮效果,重点研究了外加碳源量和水力负荷对后置反硝化BAF除污效能的影响规律。研究发现,随着外加碳源量的减少(COD/TN值由10降为4),出水COD浓度由51.9 mg/L下降到7.5 mg/L,TN浓度由3.49 mg/L增加到18.11 mg/L,而氨氮浓度变化较小,始终保持在1 mg/L以下;随着进水水力负荷由1.0 m^3/(m^2·h)逐渐增加至2.0 m^3/(m^2·h),出水COD浓度由7.44 mg/L增加到45.31 mg/L,TN由3.46 mg/L增加到17.18 mg/L,而出水氨氮浓度仍无明显变化,保持在较低水平。综合考虑进水水质和出水水质要求,确定后置反硝化BAF工艺的适宜水力负荷≤1.5 m^3/(m^2·h)、外加碳源量为COD/TN值=7,该条件下对COD、氨氮、总氮的去除效果均较好,去除率分别≥77.51%、>95%、≥87.32%。

The denitrification efficiency of the post-denitrification biological aerated filter （BAF） on the effluent of a municipal wastewater treatment plant was investigated through laboratory tests. The in- fluence of the external carbon source dosage and the hydraulic loading on the performance of the post- denitrification BAF in removing pollutants was explored in detail. The results showed that with the de- crease of the external carbon source dosage （ COD/TN ratio reduced from 10 to 4 ） , the effluent COD concentration decreased from 51.9 mg/L to 7.5 mg/L, while the TN concentration increased from 3.49 mg/L to 18.11 mg/L and the concentration of ammonia nitrogen was constantly below 1 mg/L. When the influent hydraulic loading raised from 1.0 m3/（m2 · h） to 2.0 m3/（m2 · h）, COD and TN concentra- tions in effluent increased from 7.44 and 3.46 mg/L to 45.31 and 17.18 mg/L, respectively, while no significant change in the ammonia nitrogen concentration was observed. Considering the influent quality and effluent requirements, the proper hydraulic loading of post-denitrification BAF process should be less than or equal to 1.5 m3/（ m2 · h） and the external carbon source dosage should be COD/TN = 7. Under this condition, the removal rates of COD, total nitrogen, and ammonia nitrogen were greater than or equal to 77.51%, 87.32% and above 95%, respectively.