Abstract:Aiming at the possible biological and ecological hazards caused by endocrine disrupting chemicals (EDCs) in domestic sewage, this study took steroid endocrine disruptors as the treatment object, and applied bio-ecological coupling technology to carry out a multi-stage AO+ subsurface flow constructed wetland treatment experiment. The effects of hydraulic residence time (HRT) on the removal of CODCr, ammonia nitrogen (NH4+-N), total phosphorus (TP) and total nitrogen (TN) were investigated. At the same time solid phase extraction (SPE) and GC-MS were used to detect the concentration changes of four endocrine disruptors, including estrone (E1), 17β-estrogen (E2), estriol (E3) and 17α-ethynylestradiol (EE2), in the effluent and inlet of each reactor. The results showed that when the HRT of multi-stage AO is 9.5h and that of wetland is about 10.3d, the removal rates of CODCr, NH4+-N, TP and TN could reach 78.64%, 97.16%, 91.84% and 90.55% respectively. The concentration is lower than the limit of discharge standard of main water pollutants for municipal wastewater treatment plant and key industries of Taihu area (DB32/1072-2017). The total removal rates of endocrine disruptors E1, E2, E3 and EE2 by multi-stage AO + constructed wetlands were 96.04%, 92.45%, 85.09% and 88.38% respectively. And the removal rates of E1, E2, E3 and EE2 by multi-stage AO system were 75.50%, 72.00%, 65.08% and 63.35% respectively. The first-stage aerobic tank in multi-stage AO contributed the most to the removal of four EDCs, all of which could reach more than 27%. The removal rate of the first three EDCs by wetland system were about 20%, and EE2 was 25%. Alpha diversity index analysis showed that the number and diversity of species in aerobic pond were more than those before EDCs were added. Species and abundance analysis of microbial communities in phylum and genus classifications showed that relative abundance of phylum and genus levels changed, and the increased dominant bacteria might play a role in promoting the removal of EDCs in the system.