Comparison of the cost and efficiency of Aluminum and Iron electrodes application in the removal of phosphate, nitrate, and COD from laundry wastewater using electrocoagulation process

In this study, treatability of wastewater from a laundry unit was investigated by applying electrocoagulation method in which two pairs of aluminum and iron electrodes were utilized. Electrocoagulation is a noble treatment method suitable for different kinds of wastewater which has been given a considerable attentions by researchers recently. Applying direct current to two or several suitable metallic electrode in a batch reactor containing effluent would result in flocks of metal hydroxide. We studied the effect of different operational parameters such as pH, electrodes distance, intensity of electrical current, and type of electrodes on the treatment efficiencies. Aluminum electrodes showed better effects on the treatment efficiencies in nitrate and COD removal. Maximum phosphate removal (99.93%)took place at pH=7 using Al electrodes. Whereas, in the case of iron electrode, maximum nitrate and COD removal efficiencies were about 97.60 and 80% at pH=9 and pH=6 respectively. Operational cost analysis showed that the corresponding costs of Al application as an electrode is different from that of iron electrode application. Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.