Treatment of hospital wastewater by electrocoagulation using aluminum and iron electrodes

Aims: The main goal of this study was to determine of the removal efficiency of chemical oxygen demand (COD) from educational hospital waste-water using electrocoagulation process by using iron and aluminum electrodes. Materials and Methods: A laboratory-scale batch reactor was conducted to determine the removal efficiency by the electrocoagulation method. Fifty-five samples of Shahid Mohammadi Hospital waste-water in Bandar Abbas were collected for the periods of 6 months according to standard methods. The removal of COD from the waste-water was determined at pH 3, 7, and 11 in the voltage range of 10, 20, and 30 V at the operation time of 30, 45, and 60 min. Data were analyzed in SPSS (version 16) using Pearson's correlation coefficient to analyze the relationship between these parameters. Results: The removal efficiency is increased by 6.2% with decreasing pH from 11 to 3 at the optimal condition of 30 V and 60 min operation time. By increasing the reaction time from 30 min to 60 min at voltages (10, 20, and 30 V), the removal efficiency was increased from 32.3% to 87.1%. The maximum COD removal efficiency was observed at pH 3 and voltage of 30 V and 60 min reaction time using four iron electrodes. Pearson correlation analysis showed a significant relationship between voltage and the reaction time with the removal efficiencies (P < 0.01). Conclusion: Due to the high efficiency of the electrocoagulation process and also the simplicity and relatively low-cost, it can be used for removing COD from hospital waste-water.