A Systematic Approach to Evaluate the Biodegradation Kinetics of Estrogens by Nitrifying Activated Sludge

Municipal wastewater treatment plant effluent is a major source of estrogens in the environment. This research offers an important systematic approach to evaluating the degradation of estrogens in nitrifying activated sludge systems. Protocols for estrogen extraction and analysis are provided. Methods for setting up and operating a bench scale sequencing batch reactor (SBR) and putting estrogens into solution are also discussed. Details of determining estrogen removal in a biomass are also presented, including conducting sorption isotherm experiments and biodegradation kinetics experiments with quality control procedures. The Kd values obtained in this study were 817 and 570 L kg−1 for EE2 and E2, respectively. We also achieved greater than 70% recovery when extracting estrogens sorbed onto biomass. Biodegradation rate constants for EE2 and E2 were 0.78 and 2.1 hr−1, respectively, and followed first-order kinetics. Sorption and biodegradation results agreed with those found in similar studies.