The main factors affecting the efficacy of Fenton process are
H2O2 and Fe concentrations, pH and temperature of the reaction
medium. In this study, Fenton experiments were carried out at
room temperature and pH value of 3.0 which have been reported in
a large number of studies as optimal condition for higher
pollutants removal efficiencies [27]. In our previous finding [41],
the optimized and stand-alone Fenton oxidative treatment of PRE
was established at molar ratios of 12 and 5 for [H2O2]:[COD]0 and
[H2O2]:[Fe0], respectively. However, in this study, lower concentrations
of Fenton reagent that could operate effectively were of
concern because iron and H2O2 are the main reagents that
determine the operational cost in Fenton system and have the least
residuals at the end of the reaction. Therefore, the present work is
designed to apply the heterogeneous Fenton pre-treatment step to
improve the biodegradability of the effluent to make it biologically
treatable by SBR at the subsequent step for cost effective PRE
treatment [27].