Occurrence and fate of emerging pollutants of 17beta-estradiol and testosterone in hospital wastewater and effluent: The effect of activated sludge and chlorination processes

Introduction: In 2015, the European Union placed estrogen hormones on the list of compounds with a possible real risk to living organisms and emphasized the need for environmental research. The aim of this study was to determine the occurrence and effect of activated sludge process and chlorination on the fate of 17-beta estradiol and testosterone in hospital wastewater. Materials and Methods: In this descriptive-analytical study, for each hormone, 18 samples were taken from different parts of a real scale treatment plant in a three months period. Hormone extraction was performed by solid phase extraction using selective C18 cartridge. The extracted hormones were assayed by ELISA specific kits (IBL, Germany). Data analysis was performed using SPSS software version 22 and Mann-Whitney and Wilcoxon statistical tests. Results: The minimum concentration observed in raw wastewater was related to 17β-estradiol and in the final effluent was related to testosterone. The mean concentration of testosterone in raw wastewater (6.08 ng/l) was significantly higher than the 17β-estradiol concentration (4.13 ng/l), but the difference in the mean concentrations (around 1 ng/l) of the two hormones in the final effluent was not significant. The overall efficiency of the activated sludge and chlorination processes in the removal of testosterone and 17β-estradiol was observed to be about 85% and 76%, respectively. Conclusion: Although the treatment processes can reduce considerably the concentration of 17β -estradiol and testosterone, but the final hormones concentrations indicated that the type of effluent reuse and capacity of the receiving water resources must be considered.