Water Science & Technology Vol 66 No 4 pp 754–760 © IWA Publishing 2012 doi:10.2166/wst.2012.232

Kinetic study of slaughterhouse wastewater treatment by electrocoagulation using Fe electrodes

Mohammad Ahmadian, Nader Yousefi, Steven W. Van Ginkel, Mohammad Reza Zare, Sajad Rahimi and Ali Fatehizadeh

In this study, treatment of slaughterhouse wastewater by electrocoagulation was investigated in batch system using Fe electrodes. The effect of various variables such as electrode number, current density and operating time was tested. Pollutant removal efficiency increased with increasing electrode number and operating time. The biochemical oxygen demand (BOD₅)_, chemical oxygen demand (COD), total suspended solid (TSS), and total nitrogen (TN) removal efficiencies using eight electrodes at a contact time of 50 min and a current density of 10 A/m² were 66, 62, 60, and 56%, respectively. Higher electrode numbers will allow shorter operating times to achieve certain removal efficiencies. Also, removal efficiencies increased by increasing the current density; the highest removal efficiencies of BOD_5, COD, TSS, and TN at a contact time of 50 min and a current density of 25 A/m² were 97, 93, 81, and 84%, respectively. The results also show that the reactor pH varies directly with the current density; at 25 A/m², the reactor pH increased from an initial value of 7.1 to 7.7 after 50 min. The experimental results showed that the kinetics of BOD₅, COD, TSS and TN removal could be fitted adequately using a first order kinetic model (higher R²).

Keywords: electrocoagulation; iron electrodes; kinetic study; slaughterhouse wastewater

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