Biotransformation of 17β-Estradiol through a Denitrifying Sludge.

17β-estradiol (E2) is the natural estrogen with the most significant potential for endocrine disruption in the biota of aquatic ecosystems at trace concentrations. It is, therefore, essential to study treatments for water polluted with E2 that would guarantee its complete elimination and mineralization. Denitrification is a biological process shown to have the capacity to completely biodegrade drugs, such as ampicillin. This work is aimed to evaluate the biotransformation of 17β-estradiol by employing a denitrifying sludge. The assays performed were: (I) abiotic with 3.5 mg E2-C L -1 and (II) denitrifying with 10 mg CH 3 COO - -C L -1 as the reference, 10 mg E2-C L -1 as the sole electron donor, and a mixture of (mg L -1 ) 10 E2-C with 10 CH 3 COO - -C at C N -1 of 1.1. The E2-C and NO 3 - -N consumption efficiencies were greater than 99%, and HCO 3 - -C and N 2 production yields were close to 1 in all assays. The denitrifying sludge could biodegrade up to 10 mg E2-C L -1 as the sole electron donor and when mixed with 10 mg CH 3 COO - -C L -1 . No intermediate metabolites were generated from the process.