Insights into brewery wastewater treatment by the electro-Fenton hybrid process: How to get a significant decrease in organic matter and toxicity

• Published in: Chemosphere (Oxford) Vol. 263; p. 128367
• Main Authors: Espinoza-Quiñones, Fernando Rodolfo, Dall’Oglio, Isabella Cristina, de Pauli, Aline Roberta, Romani, Maurício, Módenes, Aparecido Nivaldo, Trigueros, Daniela Estelita Goes
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-01-2021
• Subjects: Brewery wastewater treatment; Electrical conductivity model; Electro-Fenton hybrid process; H2O2 renovation; Hydrogen Peroxide; Nitrogen compound-based toxicity; Oxidation-Reduction; Total organic carbon reduction; Waste Water; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Water Purification; Brewery wastewater treatment; Nitrogen compound-based toxicity; Electro-Fenton hybrid process; Electrical conductivity model; H2O2 renovation; Total organic carbon reduction; HO renovation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.128367

This work aimed to perform selective experimental arrays based on the electro-Fenton hybrid (EFH) process for pollutants abatement and toxicity reduction in brewery wastewater (BW). Fenton and electrocoagulation (EC) methods were assessed preliminarily, including the Fe2+ catalyst yield and H2O2 loss. Each method performance on reducing total organic carbon (TOC) was assessed using a 33 full factorial design (FFD). Firstly, Fe2+ species were produced in short time ranges with the electric current density at 50 A m−2 and electrical conductivity at 1200 μS cm−1, followed by EFH experiments with an initial addition of 9.0 g L−1 H2O2. In three levels, initial pH (2.5–3.5) values, Fe2+ production-dedicated time (5–15 min), and H2O2 renovating percentage (70–90%) were also evaluated, assessing TOC removal. Secondly, nine EFH kinetics, upon the addition of an initial 9.0 g L−1 H2O2 along with H2O2 addition at 82.5%, every 5 min, and three levels for pH (3.0–3.4) were carried out, beginning after three Fe2+ production-dedicated times (4–6 min). Thirdly, another 60 min kinetic experiment was proposed, with an initial 6 min EC process, followed by a 39 min EFH process, and finally, a 15 min EC process, assessing TOC removal and remaining toxicity. A significant improvement in TOC removal performance, about 90%, along with high toxicity reduction was attained after a refined EFH-based treatment. Therefore, keeping permanent EFH conditions with more suitable parameters provided a unique perspective for removing highly significant pollutants.
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•A systematic study in improving the electro-Fenton hybrid performance was developed.•The electro-Fenton hybrid method showed a high performance in pollutant reducing.•Both total organic carbon and toxicity were systematically reduced.•Electrical conductivity has an essential role to maintain the EFH process.•Toxicity level was strongly influenced by the reminiscent total nitrogen.