Water Treatment

Water Treatment Technology – Overview

Water and waste water are treated today by various techniques, usually in combination, chosen according to the contaminants in the source water and the water quality requirements for use or discharge. New cost effective techniques are needed to treat heavily contaminated waste waters, particularly those containing toxic organic contaminants that cannot be treated in bio-reactors, and those where both removal of organic contaminants and disinfection are required.

A new plasma-based advanced oxidation technique has been developed and tested that uses an arc discharge submerged in the waste water. The arc is generated by low voltage electrical pulses. It produces plasma bubbles within the water, which produce hydroxyl OH• radicals and UV radiation. They cost effectively kill bacteria and decompose organic molecules. For 95% removal of the test molecule methylene blue, a yield of 500 g/kW-hr was achieved.

Wastewater from a pharmaceutical plant. Left: Before treatment – highly contaminated, total organic carbon (TOC) 3500 mg/l. Right: After 2 minutes of ClearWave Submerged Arc Treatment, TOC reduced to less than 175 mg/l.