Removal of macro-pollutants in oily wastewater obtained from soil remediation plant using electro-oxidation process.

Zolfaghari, Mehdi; Drogui, Patrick ORCID: https://orcid.org/0000-0002-3802-2729 et Blais, Jean-François ORCID: https://orcid.org/0000-0003-3087-4318 (2018). Removal of macro-pollutants in oily wastewater obtained from soil remediation plant using electro-oxidation process. Environmental Science and Pollution Research , vol. 25 , nº 8. pp. 7748-7757. DOI: 10.1007/s11356-017-1054-3.

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Résumé

Electro-oxidation process by niobium boron-doped diamond (Nb/BDD) electrode was used to treat non-biodegradable oily wastewater provided from soil leachate contaminated by hydrocarbons. Firstly, the diffusion current limit and mass transfer coefficient was experimentally measured (7.1 mA cm⁻² and 14.7 μm s⁻¹, respectively), in order to understand minimum applied current density. Later on, the oxidation kinetic model of each pollutant was investigated in different current densities ranged between 3.8 and 61.5 mA cm⁻². It was observed that direct oxidation was the main removal mechanism of organic and inorganic carbon, while the indirect oxidation in higher current density was responsible for nitrogen oxidation. Hydrocarbon in the form of colloidal particles could be removed by electro-flotation. On the other hand, electro-decomposition on the surface of cathode and precipitation by hydroxyl ions were the utmost removal pathway of metals. According to the initial experiments, operating condition was further optimized by central composite design model in different current density, treatment time, and electrolyte addition, based on the best responses on the specific energy consumption (SEC), chemical oxygen demand (COD), and total organic carbon (TOC) removal efficiency. Unde r optimum operating condition (current density = 23.1 mA cm⁻², time = 120 min, Ti/Pt as a cathode, and Nb/BDD as the anode), electro-oxidation showed the following removal efficiencies: COD (84.6%), TOC (68.2%), oil and grease (99%), color (87.9%), total alkalinity (92%), Ntot (18%), NH₄+ (31%), Ca (66.4%), Fe (71.1%), Mg (41.4%), Mn (78.1%), P tot (75%), S (67.1%), and Si (19.1%).

Type de document:	Article
Informations complémentaires:	Embargo
Mots-clés libres:	oily wastewater; electro-oxidation process; oxidation kinetics; optimization
Centre:	Centre Eau Terre Environnement
Date de dépôt:	29 janv. 2018 21:44
Dernière modification:	15 févr. 2022 15:51
URI:	https://espace.inrs.ca/id/eprint/6783

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