Optimization of organic compounds removal from Wastewater by Electrocoagulation

Introduction: As the most hazardous sewage, hospital wastewater contains various contaminants, and its uncontrolled discharge can seriously damage the environment. Bandar Abbas is located in an arid and semi-arid region; therefore, hospital wastewater should be treated through an appropriate and economic method. This study aimed to determine the efficiency of electrocoagulation with aluminum and iron electrodes in removal of COD from wastewater of Shahid Mohammadi Hospital of Bandar Abbas. Methods: This analysis was performed in laboratory-scale through an incoherent method using a reactor which contained iron and aluminum binary and quaternary electrodes. A total of 55 samples of raw sewage of the hospital were examined and a total of 216 samples were analyzed to determine the parameters which were effective in the process. Samples (3 L) were immediately transferred to the laboratory after collection. COD removal was performed through electrocoagulation at pH 3, 7, and 11, voltages 10, 20, and 30, and reaction times of 30, 45, and 60 min. The results were analyzed using SPSS 16 through analysis of covariance. Results: The data showed better performance of electrodes at 2 cm apart rather than 3 cm. The COD removal efficiency was increased by 6.2% when pH was decreased from 11 to 3 at optimum voltage of 30 V and reaction time of 60 min. The results showed that by increasing the reaction time from 30 to 60 min at voltages 10, 20 and 30, the efficiency of COD removal increased from 32.3% to 87.1%. Therefore, the highest efficiency of COD removal (87.1%) was obtained at optimal pH of 3, voltage of 30 V, and reaction time of 60 min with iron quaternary electrode. Conclusion: Given the high efficiency of electrocoagulation as well as its simplicity and relatively low cost, it can be used for removal of COD from hospital wastewater.