Mitsubishi Electric develops low cost water treatment technology

Japanese company Mitsubishi Electric has developed new water treatment technology that claims to treat industrial wastewater and sewage at lower cost.

The technology uses hydroxyl (OH) radicals generated through an electric discharge created at a gas/liquid interface to remove persistent organic substances in wastewater.

Mitsubishi Electric’s new technology features a reactor which uses several inclined plate electrodes in humid oxygen over which the wastewater flows.

When the water flows through the plates, a pulsed corona discharge generated at the interface of the humid oxygen gas and wastewater which produces OH radicals, a strong oxidant with an oxidation potential of 2.85 eV, compared to 2.07 eV for ozone.

With the OH radical’s high reactivity, persistent substances such as surfactants or dioxane decompose into carbon dioxide, water molecules and other inorganic compounds, the company said.

They claimed that the generation of OH radicals helps the system treat water twice more efficiently compared the conventional advanced oxidation processes, such as the combined use of ozone and ultraviolet irradiation (O3/UV).

Mitsubishi Electric also added that the use of oxygen gas is reduced significantly by up to 90% due to gas recycling.

The company is developing the technology jointly with Yasushi Minamitani, an associate professor at Graduate School of Science and Engineering, Yamagata University. They are planning to apply its technology in practical industrial wastewater and sewage reuse systems.

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Image: The water treatment system’s reactor uses several inclined plate electrodes in humid oxygen over which the wastewater flows. Photo courtesy of Mitsubishi Electric.