Abstract:Lab scale experiments were conducted to investigate the degradation potential of 17β estradiol (E2) and 17α ethinyl estradiol (EE2) by anaerobic anoxic oxic (A2O) activated sludge process.Based on the removal of nutrients and estrogen,the operational parameters such as hydraulic retention time (HRT),sludge retention time (SRT) and the recycle ratio of mixed liquor (r) were optimized.The results indicate that estrogens are dramatically removed by the A2O process.At the fixed temperature of 20℃ and sludge recycle ratio of 100%,the optimum operational parameters for HRT,SRT and r are 8 h,20 d and 300%,respectively.Under the above optimum conditions,the removal efficiencies of TN,PO3-4-P and COD are 82%,95% and 84%,respectively.E2 in the final effluent is below the detection limit; of the totally removed E2,72%,6% and 22% are removed in the anaerobic,anoxic and oxic tanks,respectively.EE2 removal efficiency is more than 80%; the anaerobic,anoxic and aerobic tanks contribute 45%,21% and 34% of the totally removed EE2,respectively.
