A~2/O-BAF系统反冲洗出水水质变化特征

针对城镇污水处理升级改造技术需求,建立一套中试规模"厌氧/缺氧/短时好氧-曝气生物滤池(A2/O-BAF)工艺",重点研究了反冲洗对BAF单元出水水质的影响。BAF池反冲洗周期为5~7 d,反冲洗方式为"气冲-气水联冲-水冲",其中,气冲10 min,气水联冲3 min,水冲3 min;该模式具有反冲洗时间短、反冲洗用水量少、操作简单等特点。在反冲洗过程中,反冲洗水的SS、COD、氨氮、总磷浓度均呈现先上升后下降的规律,说明滤料层截留的悬浮物和老化生物膜得到充分冲洗。在反冲洗1~2 d后,BAF单元出水水质恢复正常。实验表明:在该设计反冲洗模式下,可保持A2/O-BAF工艺处理效果稳定。

CHARACTERISTICS OF BACK-WASHING EFFLUENT IN A2/O-BAF SYSTEM

A pilot-scale anaerobic /anoxic /short time aerobic ( A2 /O) -biological aerated filter ( BAF) combined process was set up to treat municipal wastewater． And the object of this study was to investigate the change of the effluent during and after back-washing of the BAF． Back-washing of the BAFs was carried out every 5 ～ 7 days and the procedure included three steps: air flushing，air and water combined flushing，water flushing，with lasting time of 10min，3min and 3min，respectively． This operation mode reduced the time of back-washing，saved the volume of water used for back-washing，and the operation was simple． The concentrations of SS，COD，ammonia nitrogen and TP increased firstly and then decreased during backwashing， showing that the suspended solids and detached biofilm were washed from the filter layer． By back-washing 1 ～ 2 days later， the effluent quality of BAF resumed to normal level． The removal performance of A2 /O-BAF process could be kept stable using the present backwashing strategy．