Abstract
The versatile applications of the advanced oxidation processes (AOPs) are considered promising options for wastewaters treatment. Among AOPs, the classical Fenton process (CFP) is well recognized in literature due to its notable advantages. But the drawbacks associated with the CFP are the main barrier to its extensive applications. The primary process's drawbacks are the high sludge production and high reagents requirement, making the process unsustainable. Hence, the present study aims to overcome these drawbacks and improve the process's performance. The reagents (Fe2+ and H2O2) dosage were adopted as the variable parameters and varied throughout the experiments at fixed pH 3 and a reaction time of 45 min. The experiments were performed in three different stages; stage I (S-I: single-step reagents dosing mode), stage II (S-II: two-step reagents dosing mode), and stage III (S-III: three-step reagents dosing mode) and landfill leachate was taken as a sample. The dosing mode of reagents was found to be a crucial influencing factor to improve the overall Fenton process's performance by effectively utilizing the hydroxyl radicals (center dot OH) and avoiding the scavenging reactions. The twostep reagents dosing mode was found better, i.e., 52 +/- 2% chemical oxygen demand (COD) removal and 40 +/- 2 mL sludge production compared to S-I and S-III with approximately 10-15% extra COD removal and low sludge production at fewer reagents dosage (Fe2+ dosage 798 mg/L and H2O2 dosage 2098 mg/L). The lesser sludge production reduces secondary environmental pollution, and low reagents dosage makes the process costeffective. The optimization conditions were obtained by response surface methodology (RSM), and high coefficient of determination (R2 > 0.95) values confirm the adequacy of the models obtained. Furthermore, few experiments were performed on the sludge reusability, and valuable remarks were highlighted. Overall, the purpose of this study is to enhance the CFP's performance by overcoming its drawbacks.