The removal of bisphenols and other contaminants of emerging concern by hydrodynamic cavitation: From lab-scale to pilot-scale

The rapid growth in the variety and quantity of contaminants of emerging concern (CEC) in wastewater indicates the necessity for developing efficient and environmentally friendly methods for their removal. This study investigates the removal efficiency of 46 CEC, including 12 bisphenols, from wastewater using a lab and pilot-scale hydrodynamic cavitation generator alone and in combination with UV illumination (pilot-scale). During lab-scale cavitation, the highest removal efficiencies of bisphenols (15-63%) for this specific design of cavitator were obtained at a rotational frequency (v(cav)) = 9500 rpm and time (t(cav)) = 10 min. Temperature and the physicochemical properties (e.g. K-ow) of the studied compounds also had a significant effect on removal efficiency. At the pilot-scale, 11 CECs were quantifiable in the wastewater influent, and the generator operated at nu(cav) = 2290 and 2700 rpm. The highest removal efficiencies (15-90%) were obtained at a lower nu(cav) = 2290 rpm while neither an increase in nu(cav), t(cav) or the presence of UV-C light increased the removal efficiency. A lower nu(cav) also reduced the hydrodynamic power of the cavitator from 477 W to 377 W, resulting in reduced energy consumption. Overall, the results show the potential of hydrodynamic cavitation for a large-scale application as a pre-treatment technology and pave the way for future improvements in the design of cavitation reactors. (C) 2020 Published by Elsevier B.V.