Predicting influent estradiol and estrone concentrations for wastewater treatment facilities

An externally validated model was developed to predict influent concentrations of natural estrogens at municipal wastewater plants. The model kinetic constant for the first-order biotransformation of estradiol into estrone, k(E2), was calculated as 0.030 hour(-1) (ranging from -0.080 to 0.49 hour(-1), with a standard deviation of 0.23) and the model value for the biodegradation k of estrone, k(E1), was -0.18 hour(-1) (ranging from -0.44 to 0.38 hour(-1), with a standard deviation of 0.3). The k values were not found to be temperature-sensitive within the range 12 to 24.5 degrees C and displayed a weak trend of increasing with total suspended solids within the range 0.103 to 0.450 g/L. The new model improved on the predictions of a previous model for influent estrone concentrations, but gave comparable results for estradiol.