Field evaluation of a photocatalytic oxidation technology

A commercial-scale photocatalytic oxidation system developed by Matrix Photocatalytic Inc. (Matrix) was evaluated to generate performance and cost data for the treatment of groundwater contaminated with volatile organic compounds (VOCs). High percent removals (up to 99.9%) were observed for aromatic and unsaturated VOCs. However, saturated VOC removals were insignificant. Oxidant addition to the contaminated groundwater significantly improved the treatment system performance. The Matrix system performance was reproducible under identical operating conditions. Treatment by the Matrix system did not reduce the groundwater toxicity for water fleas and fathead minnows at the 95% confidence level. Toxicity reduction achieved through VOC removal appears to have been negated by the formation of toxic byproducts including aldehydes and haloacetic acids. Estimated treatment costs are about $7.60 per 1,000 litres of groundwater.