Kinetics of Biological Removal of the Selected Micropollutants and Their Effect on Activated Sludge Biomass.

17α-Ethinylestradiol (EE2), diclofenac (DCF), and 4-nonylphenol (4NP) belong to the most common micropollutants (MPs) occurring in municipal wastewater treatment plants (WWTPs). The WWTPs are the primary barrier against the spread of micropollutants in the environment. The aim of this work was to study the kinetics of biological removal of the three aforementioned micropollutants from wastewater and to check whether the acclimation of biomass influenced on the kinetic parameters. In addition, the effect of MPs on the biochemical activity of microorganisms was tested. DCF inhibited the respiration activity of biomass to the highest extent, followed by 4NP and EE2, respectively. DCF occurred to be less susceptible to microbial decomposition than the other two MPs and was removed from wastewater at the lowest degree of 58%. The degrees of removal of EE2 and 4NP were higher than that of DCF and equal to 93 and 71%, respectively. The kinetic parameters determined in this work can be used in modelling and simulation of the removal of micropollutants from wastewater. They improve the predictive ability of the biokinetic models. The acclimation of the biomass to the relevant micropollutant does not influence on the kinetic parameters of biomass growth; however, it causes the increase of the yield coefficient for heterotrophic biomass.