Development of a novel electrochemical coagulant dosing unit for water treatment

Abstract

The design of new approaches that help to decrease both the environmental impact of industrial activities and the cost of existing water treatment technologies is becoming a key aspect of research. In the present work, an efficient and easy-to-use electrochemical device designed to dose iron coagulants is presented. The proposed device (the Electrochemically-assisted Coagulant – production & dosing Unit, ECU) exhibits an efficient performance in the dosing of coagulants regardless of the ionic conductivity of the water matrixes tested (within the range 100 to 1000 µS cm−1), covering a wide range of potential real surface waters. The behaviour of the ECU device was compared to that of a conventional chemical dosing of iron, and showed better pH (pH ≈ 8 for ECU but < 4 for equivalent chemical dosing) and conductivity (decrease for ECU but increase up to 60% for equivalent chemical dosing) control. Moreover, the ECU unit produced a noticeable amount of Fe2+ ions, due to the limited access of atmospheric oxygen inside the device. The device developed overcomes traditional chemical iron dosing and could be potentially applied in uses different from electrocoagulation, as it is the case of Fenton-related technologies.