Domestic greywater treatment using electrocoagulation-electrooxidation process: optimisation and experimental approaches

Milad Mousazadeh; Nastaran Khademi; Işık Kabdaşlı; Seyedahmadreza Rezaei; Zeinab Hajalifard; Zohreh Moosakhani; Khalid Hashim

doi:10.1038/s41598-023-42831-6

Domestic greywater treatment using electrocoagulation-electrooxidation process: optimisation and experimental approaches

Sci Rep. 2023 Sep 22;13(1):15852. doi: 10.1038/s41598-023-42831-6.

Authors

Milad Mousazadeh^#^{1

2}, Nastaran Khademi³, Işık Kabdaşlı^#⁴, Seyedahmadreza Rezaei⁵, Zeinab Hajalifard⁶, Zohreh Moosakhani⁷, Khalid Hashim⁸

Affiliations

¹ Social Determinants of Health Research Center, Research Institute for Prevention of Non-Communicable Diseases, Qazvin University of Medical Sciences, Qazvin, Iran. m.milad199393@gmail.com.
² Department of Environmental Health Engineering, School of Health, Qazvin University of Medical Sciences, Qazvin, Iran. m.milad199393@gmail.com.
³ Health, Safety and Environment Specialist, National Iranian Drilling Company, Ahvaz, Iran.
⁴ Civil Engineering Faculty, Environmental Engineering Department, İstanbul Technical University, Ayazağa Campus, 34469, Maslak, İstanbul, Turkey.
⁵ Department of Engineering, Faculty of Civil Engineering, Persian Gulf University, Bushehr, Iran.
⁶ Department of Chemical Engineering, Amirkabir University of Technology, Hafez Av., Tehran, Iran.
⁷ Department of Environmental Health Engineering, School of Health, Qazvin University of Medical Sciences, Qazvin, Iran.
⁸ Built Environment and Sustainable Technologies Research Institute (BEST), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK.

^# Contributed equally.

Abstract

A synergistic combination of electrocoagulation-electrooxidation (EC-EO) process was used in the current study to treat domestic greywater. The EC process consisted of an aluminium (Al) anode and an iron (Fe) cathode, and the EO process consisted of titanium with platinum coating mesh (Ti/Pt) as an anode and stainless steel as a cathode. The effect of operative variables, namely current density, pH, EC time and EO time, on the removal of chemical oxygen demand (COD), colour, turbidity, and total organic carbon (TOC) was studied and optimised using Response Surface Methodology (RSM). The results showed that although the pH affected the removal of all studied pollutants, it had more effect on turbidity removal with a contribution of 88.44%, while the current density had the main dominant effect on colour removal with a contribution of 73.59%. It was also found that at optimal operation conditions for a current density of 2.6 A, an initial pH of 4.67, an EC time of 31.67 min, and an EO time of 93.28 min led to a COD, colour, turbidity, and TOC removal rates of 96.1%, 97.5%, 90.9%, and 98%, respectively, which were close to the predicted results. The average operating cost and energy consumption for the removal of COD, colour, turbidity, and TOC were 0.014 $/m³ and 0.01 kWh/kg, 0.083 $/m³ and 0.008 kWh/kg, 0.075 $/m³ and 0.062 kWh/kg, and 0.105 $/m³ and 0.079 kWh/kg, respectively.