Removal pathway and mechanisms of 17α-ethinylestradiol in eco-pond systems for wastewater treatment

Abstract:

To investigate pathway and possible removal mechanisms of 17α-ethinylestradiol(EE2) in ecopond systems(algae ponds and duckweed ponds) for wastewater treatment,all of the laboratory scale batch tests,dynamic sorption tests and continuous flow tests were conducted to study the effect of sorption and biodegradation on EE2 removal.EE2 concentrations were detected by enzyme-linked immunosorbent assay(ELISA).The 6-day batch tests showed that the introduction of duckweed and algae into wastewater could enhance EE2 removal rate.In the 180-min dynamic sorption tests,about 25% and 80% of EE2 were sorbed by algae and duckweed respectively,which means occurrence of the swift sorption,while the mass balances indicated that only about 6% of the estrogens were bound to the biomass of algae or duckweed at the end of the 6-day tests,implying that EE2 was rapidly removed by sorption at the initial stage,while the sorbed EE2 was subsequently eliminated by biodegradation.Results of continuous flow tests revealed that even at ng/L level,EE2 could also be removed in algae and duckweed pond systems.Sorption and biodegradation are the main removal mechanisms of EE2 in eco-pond systems.