A^2/O工艺中HRT对系统脱氮除磷效率的影响

Effect of HRT on performance of nitrogen and phosphorus removal by A^2/O process

水力停留时间是制约A2/O工艺的关键因素,直接影响系统的脱氮除磷效率.本试验采用了50 L的A2/O实验装置处理人工模拟生活污水,考察了不同水力停留时间(Hydraulic Residence Time,HRT)对A2/O工艺脱氮除磷的影响.实验结果表明,在厌氧∶缺氧∶好氧体积比为1∶1∶2,污泥回流比为75%,混合液回流比为200%的工况下处理生活污水,HRT对COD的影响较小,对NH3—N、TN以及TP的去除率影响较大,HRT为8 h时,系统处理效果最佳.碳源不足同样制约着TN和NH3—N的去除率.TN、NH3—N的去除相对COD去除比较需要较长的HRT,而HRT过长又对TP的去除不利.

HRT is the key factor which restricts biological nutrients and phosphous removal by A2/O process.This paper discussed on how the HRT affect the removals of nitrogen and phosphorus in synthetic brewage wastewater treatment plant in A2/O process with a working volume of 50 L.The result found that the HRT has less effect of COD removal than that of ammonia nitrogen,TN and TP.The effect reached best when HRT was 8 h.The volume ratio of anaerobic∶anoxic∶aerobic zone was 1∶1∶2 and sludge recycle ratio 75%,return ratio of mixed liquor of 200%.The results showed that COD removal needs longer HRT than TN and NH3—N removal,but it was disadvantageous to TP removal when HRT was too long.