Background: Conventional wastewater treatment plants discharge significant amounts of
antibiotic resistant bacteria and antibiotic resistance genes into natural water bodies contributing to the
spread of antibiotic resistance. Some advanced wastewater treatment technologies have been shown to
effectively decrease the number of bacteria. Nevertheless, there is still a lack of knowledge about the
effectiveness of these treatments on antibiotic resistant bacteria and antibiotic resistant genes. To the
best of our knowledge, no specific studies have considered how powdered activated carbon (PAC)
treatments can act on antibiotic resistant bacteria, although it is essential to assess the impact of this
wastewater treatment on the spread of antibiotic resistant bacteria.
Methods: To address this gap, we evaluated the fate and the distribution of fluorescent-tagged antibiotic/
antimycotic resistant microorganisms in a laboratory-scale model simulating a process configuration
involving powdered activated carbon as advanced wastewater treatment. Furthermore, we studied
the possible increase of naturally existing antibiotic resistant bacteria during the treatment implementing
Results: The analysis of fluorescent-tagged microorganisms demonstrated the efficacy of the PAC adsorption
treatment in reducing the load of both susceptible and resistant fluorescent microorganisms in
the treated water, reaching a removal efficiency of 99.70%. Moreover, PAC recycling did not increase
the resistance characteristics of cultivable bacteria neither in the sludge nor in the treated effluent.
Conclusion: Results suggest that wastewater PAC treatment is a promising technology not only for the
removal of micropollutants but also for its effect in decreasing antibiotic resistant bacteria release.