Removal of organic pollutants from sugarcane stillage using UV-assisted Fenton process

Abstract

Stillage or distillery wastewater have been reported as industrial effluent that are difficult to be treated as its discharge in the water bodies presents contamination with recalcitrant and non-degradable pollutants. Due to their complicated structure, stillage treatment process using traditional methods such as adsorption, coagulation, and flocculation is challenging. Fenton reaction has been found as an effective method to degrade these contaminants through hydroxyl radicals. In this study, the removal of pollutants in stillage was investigated using UV-assisted Fenton process. Experiments was conducted for 60 minutes in a batch reactor with initial pH of stillage 4.5, UV lamp of 395-400 nm, and constant speed of 250 rpm, while the dosages of H2O2 and Fe (II) were kept constant at 3.3 g/L and 0.6 g Fe/L, respectively. The profile of chemical oxygen demand (COD) removal, pH, temperature, and oxidation-reduction potential (ORP) was evaluated under three dilution factors of raw stillage (1/10; 1/25; and 1/50) during treatment process to investigate the effects of these parameters on treatment efficiency. It has been observed that initial COD of stillage had considerable effect on the performance of UV-photo-Fenton treatment, as higher dilution factor increases the removal efficiency of COD from stillage. The degradation of COD by UV-assisted Fenton was found to be suitably described by the pseudo-first-order kinetics. The results obtained from this work indicated that UV-Fenton can be introduced as a successful advanced treatment process for efficient degradation of stillage.