Removal of 17β-estradiol in a Biological Active Carbon Reactor with Acetic Acid and Humic Acid.

  The objective of this study is to characterize the removal of 17β-estradiol (E2) and the microbial community of a biologically active carbon (BAC) reactor under acetic acid or humic acid as the primary carbon source. Influent E2 concentration was maintained at 20 μg/L. Higher than 99% removal of E2 was achieved by the BAC reactor. The concentration of E2 increased from below detection limit (<5.8 ng/L) to 48 ± 8 ng/L after switching the primary carbon source from acetic acid to humic acid in the reactor influent. Meanwhile, effluent estrone concentration increased from 50 ± 15 to 55 ± 15 ng/L after the switch of primary carbon source in the reactor influent. 17β-estradiol degrading bacteria were isolated. Microbial community structures under different nutrient conditions were revealed by high throughput sequencing. The presence of readily biodegradable carbon source such as acetic acid benefited E2 removal in the BAC reactor.