What is Electrochemical Water Disinfection

What is Electrochemical Water Disinfection?

Electrochemical water disinfection can be defined as the elimination of microorganisms from a water sample using the passage of electrical current through that sample. Here the electrode materials are very important because upon application of the electrical current electrochemical reactions occur at the surface of the electrodes. At the cathode, hydrogen gas is produced, and at the anode, oxygen gas is produced along with oxidizing compounds that can include ozone, free chlorine, peroxide, and free radicals such as hydroxyl radicals or superoxide radicals.

These compounds move into the solution and oxidize microorganisms and other organic materials. It has been demonstrated that disinfection is faster and more complete at a higher current density. A faster treatment reduces the size and therefore capital cost of a wastewater treatment plant by eliminating the need for large holding tanks and reactors. As the applied current is increased the required voltage will also increase. This poses two problems: 1) commonly used anode materials deactivate or dissolve; and 2) the power consumption of these anodes increases. In order to solve these problems, an anode material must be developed that is stable and conductive at high voltages.

Dimensionally stable anodes (DSAs) are increasingly being studied for use in electrochemical wastewater treatment. DSAs typically consist of mixed metal oxide coatings on valve metal substrates. Boron doped diamond (BDD) electrodes are also being investigated for use in electrochemical wastewater treatment. These electrodes consist of a diamond film that is doped with boron to create a semiconductor.