Oxidative removal of stabilized landfill leachate by Fenton's process: process modeling, optimization & analysis of degraded products

Abstract

In this study, the stabilized landfill leachate which has a BOD : COD ratio of 0.045 was treated using Fenton's process. The effect of process parameters like reaction time, pH, dose of FeSO₄ and dose of H₂O₂ was estimated using One Factor At a Time (OFAT) and the linear, interactive and quadratic effects between the factors were studied using Face Centered Central Composite Design (CCF). In the OFAT approach, reaction time: 5 minutes, pH: 3.0, dose of FeSO₄: 30 mM, and dose of H₂O₂: 30 mM were optimized. In CCF, the statistically optimized model shows maximum removal of organic substances at an FeSO₄ concentration of 14.44 mM, pH 3.0 and 29.12 mM of H₂O₂. The regression co-efficient R² = 0.9079, adj R² = 0.854 and adequate precision = 14.676. The degradation of organic substances was assessed by measuring the Chemical Oxygen Demand (COD). Total Organic Carbon (TOC) and Gas Chromatography-Mass Spectroscopy (GC-MS) were investigated for the sample corresponding to the maximum COD reduction.