The effects of ultrasound and electrocoagulation on removal of manganese from wastewater

Abstract

In this paper the effects of ultrasound and electrocoagulation on removal of manganese from wastewater is studied. Manganese is common in industrial and metallurgical wastewaters, as well as in groundwater supplies, and its higher concentrations represent an increased risk of aquifer pollution. It was shown that 20 kHz ultrasound alone is not very efficient for manganese removal, but it enhances the efficiency of electrocoagulation. It was also shown that settling has a great effect on the electrocoagulation process because it stabilizes the flocs. Totally, four experiments on a laboratory scale were conducted and the optimal one included 10 minutes of ultrasound and 10 minutes of electrocoagulation using iron electrodes. Under these conditions 89.0 % of manganese was removed with operational costs of 0.13 EUR/mg Mn. Further, by including the cost of immersed ultrasound probe replacement, total operational costs increased up to 3000 times, making immersed ultrasound process unprofitable for a large-scale application.