PAHs remediation from hazardous waste landfill leachate using fenton, photo - fenton and electro - fenton oxidation processes - performance evaluation under optimized conditions using RSM and ANN

Pradeep Kumar Singa; Mohamed Hasnain Isa; Baskaran Sivaprakash; Yeek-Chia Ho; Jun-Wei Lim; Natarajan Rajamohan

doi:10.1016/j.envres.2023.116191

PAHs remediation from hazardous waste landfill leachate using fenton, photo - fenton and electro - fenton oxidation processes - performance evaluation under optimized conditions using RSM and ANN

Environ Res. 2023 Aug 15;231(Pt 2):116191. doi: 10.1016/j.envres.2023.116191. Epub 2023 May 20.

Authors

Pradeep Kumar Singa¹, Mohamed Hasnain Isa², Baskaran Sivaprakash³, Yeek-Chia Ho⁴, Jun-Wei Lim⁵, Natarajan Rajamohan⁶

Affiliations

¹ Department of Civil Engineering, Guru-Nanak Dev Engineering College, Bidar, 585403, Karnataka, India. Electronic address: pmsinga@gmail.com.
² Department of Civil Engineering, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong, BE1410, Brunei Darussalam.
³ Department of Chemical Engineering, Annamalai University, Annamalai Nagar PC, 608002, India.
⁴ Civil and Environmental Engineering Department, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia. Electronic address: yeekchia.ho@utp.edu.my.
⁵ Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia.
⁶ Chemical Engineering Section, Faculty of Engineering, Sohar University, Sohar, PC-311, Oman. Electronic address: rnatarajan@su.edu.om.

PMID: 37211185
DOI: 10.1016/j.envres.2023.116191

Abstract

Polycyclic aromatic hydrocharbons (PAHs) are a class of highly toxic pollutants that are highly detrimental to the ecosystem. Landfill leechate emanated from municipal solid waste are reported to constitute significant PAHs. In the present investigation, three Fenton proceses, namely conventional Fenton, photo-fenton and electro-fenton methods have been employed to treat landfill leehcate for removing PAHs from a waste dumpig yard. Response surface methodology (RSM) and artificial neural network (ANN) methodologies were adopted to optimize and validate the conditions for optimum oxidative removal of COD and PAHs. The statistical analysis results showed that all independent variables chosen in the study are reported to have significant influence of the removal effects with P-values <0.05. Sensitivity analysis by the developed ANN model showed that the pH had the highest significance of 1.89 in PAH removal when compared to the other parameters. However for COD removal, H₂O₂ had the highest relative importance of 1.15, followed by Fe²⁺ and pH. Under optimal treatment conditions, the photo-fenton and electro-fenton processes showed better removal of COD and PAH compared to the Fenton process. The photo-fenton and electro-fenton treatment processes removed 85.32% and 74.64% of COD and 93.25% and 81.65% of PAHs, respectively. Also the investigations revelaed the presence of 16 distinct PAH compunds and the removal percentage of each of these PAHs are also reported. The PAH treatment research studies are generally limited to the assay of removal of PAH and COD levels. In the present investigation, in addition to the treatment of landfill leachate, particle size distribution analysis and elemental characterization of the resultant iron sludge by FESEM and EDX are reported. It was revealed that elemental oxygen is present in highest percentage, followed by iron, sulphur, sodium, chlorine, carbon and potassium. However, iron percentage can be reduced by treating the Fenton-treated sample with NaOH.

Keywords: Artificial neural network; COD; Fenton oxidation process; Landfill leachate; PAH; Response surface methodology.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ecosystem
Hydrogen Peroxide / chemistry
Iron / chemistry
Oxidation-Reduction
Solid Waste / analysis
Water Pollutants, Chemical* / analysis

Substances

Water Pollutants, Chemical
Hydrogen Peroxide
Iron
Solid Waste