Removal of 17α-ethinylestradiol in Algae and Duckweed Based Wastewater Treatment Systems

摘要

In this work, removal of 17α-ethinylestradiol (EE2) in both batch tests and continuous flow experiments was studied. EE2 concentration was measured with ELISA kits. In 6-day batch tests with synthetic wastewater seeded with duckweed or algae, more than 90% of an initial amount of 1 μg/L EE2 disappeared. Similar tests with unseeded tap water resulted only in 13% EE2 removal. Surprisingly however, high removal efficiencies were also observed in a batch test with synthetic wastewater but without algae or duckweed, indicating that chemical degradation could play a major role. Lab-scale continuous flow tests at a hydraulic retention time of 1 S days showed that EE2 concentrations decreased from 9.71 ng/L in the influent to 0.59ng/L and 1.28ng/L in the effluents of algae ponds and duckweed ponds, respectively. Experiments were also done to discriminate between EE2 adsorption and degradation. EE2 adsorption rate were 0.83-1.18ng/g duckweed (dry weight). 2.11-4.0ng/g and 0.44-1.0ng/g dry sediment from algae pond and duckweed pond, respectively. A main conclusion from this work is that EE2 can be effectively removed from wastewater in algae and duckweed ponds and that both chemical and biological degradation might play a key role in the removal of EE2 from wastewater.