Title: Treatment of petroleum wastewater using a sequential hybrid system of electro-Fenton and NZVI slurry reactors, future prospects for an emerging wastewater treatment technology

Authors: Mirmehdi Seyyedi; Bita Ayati

Addresses: Civil and Environmental Engineering Faculty, Tarbiat Modares University, Tehran, Iran ' Civil and Environmental Engineering Faculty, Tarbiat Modares University, Tehran, Iran

Abstract: In this study, treatment of a 750 mL petroleum wastewater sample was evaluated using a hybrid system consisting of electro-Fenton and nano zero-valent iron (NZVI) slurry reactors in sequence. In both systems, effective parameters were optimised by one-factor-at-a-time (OFAT) method considering energy consumption and treatment efficiency. For the slurry reactor, nanoparticles were first synthesised and then used in the reactor to treat the wastewater. Both systems were first optimised separately and the hybrid complex was designed based on the sub-systems optimum conditions. As for the electro-Fenton reactor, maximum COD removal efficiency of 92.78% was achieved in 75 minutes once having optimum initial pH and current values of 3 and 0.5 A respectively. In the slurry reactor, COD removal efficiency of 86.94% was achieved in 60 minutes while having 0.1 g/L of NZVI concentration and neutral initial pH as components of optimum parametric condition. Finally, in the hybrid system, a higher COD removal efficiency of 93.46% was achieved in only 47 minutes. Moreover, consumed energy for achieving the mentioned efficiency was 12.672 KJ being 40% less than that of single electro-Fenton system.

Keywords: advanced oxidation; electro-Fenton; NZVI; petroleum wastewater; hybrid system.

DOI: 10.1504/IJEWM.2021.118369

International Journal of Environment and Waste Management, 2021 Vol.28 No.3, pp.328 - 348

Accepted: 08 Sep 2019
Published online: 25 Oct 2021 *

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