Optimization of Fenton process for concurrent COD removal and lower sludge production: Process intensification and impact of reagents dosing mode

Mohd Salim Mahtab; Izharul Haq Farooqi; Anwar Khursheed

doi:10.1016/j.jenvman.2022.115207

Optimization of Fenton process for concurrent COD removal and lower sludge production: Process intensification and impact of reagents dosing mode

J Environ Manage. 2022 Aug 1:315:115207. doi: 10.1016/j.jenvman.2022.115207. Epub 2022 May 4.

Authors

Mohd Salim Mahtab¹, Izharul Haq Farooqi², Anwar Khursheed³

Affiliations

¹ Department of Civil Engineering, Z.H. College of Engineering and Technology, Aligarh Muslim University, Aligarh, 202002, India. Electronic address: msmahtab@zhcet.ac.in.
² Department of Civil Engineering, Z.H. College of Engineering and Technology, Aligarh Muslim University, Aligarh, 202002, India.
³ Department of Civil Engineering, Z.H. College of Engineering and Technology, Aligarh Muslim University, Aligarh, 202002, India; Department of Civil Engineering, College of Engineering, King Saud University, Riyadh, 11421, Saudi Arabia.

PMID: 35525036
DOI: 10.1016/j.jenvman.2022.115207

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 (^•OH) and avoiding the scavenging reactions. The two-step 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 cost-effective. 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.

Keywords: Cost-effective treatment; Fenton process; Leachate treatment; Optimization; Sustainable solution; Waste minimization.

MeSH terms

Biological Oxygen Demand Analysis
Hydrogen Peroxide
Indicators and Reagents
Iron
Oxidation-Reduction
Sewage*
Water Pollutants, Chemical* / analysis

Substances

Indicators and Reagents
Sewage
Water Pollutants, Chemical
Hydrogen Peroxide
Iron