title: Degradation and biodegradability improvement of the olive mill wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes.
abstract: Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD5), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO2/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m(2), 1000 mg/L H2O2, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96%, BOD5 by 93.6%, total, polyphenols by 94.4%, color by 91.4%, turbidity by 88.7, suspended solids by 97% and oil and grease by 97.1%. The biodegradability index (BOD5/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.
authors.affiliation: Department of Environmental Health Engineering, Health Sciences Research Center, Faculty of Health, Mazandaran University of Medical Sciences, Sari, Iran, esfandyari496@gmail.com.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Esfandyari
authors.forename: Yousef
authors.initials: Y
authors.lastname: Mahdavi
authors.forename: Mahdi
authors.initials: M
authors.lastname: Seyedsalehi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hoseini
authors.forename: Gholam Hossein
authors.initials: GH
authors.lastname: Safari
authors.forename: Mohammad Ghanbari
authors.initials: MG
authors.lastname: Ghozikali
authors.forename: Hossein
authors.initials: H
authors.lastname: Kamani
authors.forename: Jalil
authors.initials: J
authors.lastname: Jaafari
mesh_terms: D000535:Aluminum; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D001714:Bipolar Disorder; D055664:Electrochemical Techniques; D004564:Electrocoagulation / Q000379:methods*; D004566:Electrodes; D019649:Food Industry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis*; D031658:Olea; D000069463:Olive Oil; D010938:Plant Oils; D014025:Titanium; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000535:Aluminum; D006861:Hydrogen Peroxide; D007220:Industrial Waste; D000069463:Olive Oil; D010938:Plant Oils; D014025:Titanium; D062065:Wastewater; D014874:Water Pollutants, Chemical