Abstract
Wastewater streams and particularly industrial effluents tend to increase in volumes and to get more complex in terms of
pollution. Nevertheless, nowadays the focus is directed towards recycling or reuse of treated wastewater so as to close the water
use loop. Advanced wastewater treatment allows these possible applications by achieving good quality effluent to suit the new
purposes, but the implementation of this treatment stage is a difficult task. This study gives an example on how to approach an
advanced treatment process (ultrasonication), starting from laboratory experiments. An assessment of the ultrasonication process
efficiency for the removal of a textile dye (Reactive Blue 19), from aqueous dye solutions is presented. The experiments were
performed on an ultrasonic horn, at 20 kHz frequency. The ultrasonic parameters studied are: acoustic wave amplitude, power
density (dependent on the surface of the tip), operating mode (pulse or continuous), initial dye concentration and energy
consumption. By using process modeling (Matlab software), a linear model with interactions was proposed. The goal was to
optimize both pollutant removal efficiencies and energy consumption, and the optimum results obtained are: 57% removal
efficiency expressed as decolonization, 18.73% removal efficiency expressed as Total Organic carbon (TOC) reduction and
(4.98ą0.17)*105 kJ energy consumed, in the pulse operating mode and 44%, respectively 30.28%, and (6.37ą0.22) *105 kJ, in the
continuous operating mode, for 0.5 L sample. The optimization provides information on the best working conditions that can be
applied for the treatment of aqueous dye solutions by using the ultrasonication process.