Introduction:

Due to the increased toxicity of wastewater and the limited efficiency of conventional systems, the application of alternative processes is required, among which the sono-photo-Fenton system is highlighted.

Objective:

This work aims at optimizing the variables that directly affect the oxidation power of the sono-photo-Fenton process, such as the pH of the solution and the concentration of the oxidizing and the promoting agents, for the treatment of a petrochemical wastewater, in order to validate the suitability of using designs of experiments based on a reduced number of runs.

Materials and methods:

For this purpose, a face-centered composite central experiment design was used, whose second-order regression model was validated. The results achieved were compared to those ones reported in the literature using a larger number of experimental runs.

Results:

Under optimized operating conditions (3 pH units, 525 mg/L H2O2 and 25,70 mg/L Fe2+), COD removals > 70 % were obtained. These results were similar to the optimal conditions previously obtained and informed in the literature by using a full factorial experiment design.

Conclusions:

Therefore, it is demonstrated the importance of conducting designs of experiments that allow optimizing water treatment systems using a reduced number of runs, which results in the reduction of both economic costs and times of experimentation and analysis of the response variable of interest.