ABSTRACT
Arsenic (As) is a toxic element and should be removed from water meant for drinking purposes. As per WHO, the As concentration in drinking water should be below 10 µg/L. In water As is present in two forms: arsenite (As(III)) and arsenate (As(V)) and the removal of As(III) by conventional techniques is effective when it is oxidized to the more easily removed As(V) oxyanion. However, the common techniques used for As(III) oxidation and its subsequent removal have various drawbacks. The new concept of biological oxidation of As(III) by arsenic oxidizing bacteria (AsOB) and its removal by adsorption to iron precipitates generated by iron-electrocoagulation (Fe-EC) has shown theoretical advantages over conventional technologies. Hence, this study aimed to combine oxidation of As(III) by groundwater-native AsOB with low charge dosage Fe-EC to remove 150 µg/L of As(III) below 10 µg/L in continuous flow mode. The removal efficiency of As(III) increased from 70% to 99% by applying biological oxidation prior to Fe-EC, making this integrated approach a novel and effective technique to remove As(III) from water.
