Influence of manganese and ammonium oxidation on the removal of 17α-ethinylestradiol (EE2)

Flow-through reactors with manganese oxides were examined for their capacity to remove 17 alpha-ethinylestradiol (EE2) at mu g L-1 and ng L-1 range from synthetic wastewater treatment plant (WWTP) effluent. The mineral MnO2 reactors removed 93% at a volumetric loading rate (B-V) of 5 mu g EE2 L-1 d(-1) and from a B-V of 40 mu g EE2 L-1 d(-1) on, these reactors showed 75% EE2 removal. With the biologically produced manganese oxides, only 57% EE2 was removed at 40 mu g EE2 L-1 d(-1). EE2 removal in the ng L-1 range was 84%. The ammonium present in the influent (10 mg N L-1) was nitrified and ammonia-oxidizing bacteria (AOB) were found to be of prime importance for the degradation of EE2. Remarkably, EE2 removal by AOB continued for a period of 4 months after depleting NH4+ in the influent. EE2 removal by manganese-oxidizing bacteria was inhibited by NH4+. These results indicate that the metabolic properties of nitrifiers can be employed to polish water containing EE2 based estrogenic activity. (C) 2008 Elsevier Ltd. All rights reserved.