Treatment of Persistent Organic Pollutants in Wastewater by Nano-Seconds Pulsed Discharge Plasma

Abstract

Persistent organic pollutants (POPs) are bioaccumulative and environmentally persistent substances. POPs cannot be decomposed by conventional water treatments. For this reason, a new treatment method is required. Nano-seconds (ns) pulsed discharges enable higher energy efficiencies of plasma processing. Its advantages have been already performed at gas phase treatment such as NOx treatment and ozone generation. On the other hand, there are few reports on the water treatment using ns discharge plasmas. In this study, we tried to decompose the organic pollutants using ns method by spraying wastewater into gas phase plasma region. The discharge reactor was coaxial cylindrical geometry, and the treated wastewater was circulated and continuously treated in the reactor. The time course of pH and concentration of total organic carbon (TOC) in the wastewater were evaluated at different applied voltages. From the results, the decrease of TOC in the wastewater was observed together with pH at ns discharge treatment. The experimental results showed that the ns pulsed discharge plasma can decompose TOC in the wastewater and has discoloration effect.