It was demonstrated that the concentration of H2O2 (and thus the concentration of PAA) is increased when the fluid enters the cell through the anodic chamber and exists through the cathodic chamber.It was explained in the base of the concurrence of parasitic reactions. On the one hand, if the fluid comes out of the cell through the cathodic chamber, where the H2O2 is being produced, its concentration is the highest at the outlet of the cell, where it is available to react with CH3COOH. On the other, if the cathodic chamber is placed first, the fluid circulates latter through the anode, where H2O2can be oxidized, diminishing the overall efficiency of the process.