Gaseous By-products from Pulsed Arc Electrohydraulic Discharge Treatment of Contaminated Urban Stormwater
O. L. Li1, Y. Guo1, Z. He2, and J. S. Chang3
1Department of Civil Engineering, McMaster University, Canada
2Department of High Voltage Engineering, Huazhong University of Science and Technology, China
3Department of Engineering Physics, McMaster University, Canada
Abstract— The Pulsed Arc Electrohydraulic Discharge (PAED) direct plasma technique has been applied for various water treatment purposes. Although the chemical reactions, radical generation and UV radiation in PAED treatment have been widely investigated, limited study has been conducted for gaseous by-products generated during the treatment process. An experimental investigation of gaseous by-products from PAED treatment of urban stormwater in detention ponds was conducted. The experimental system consists of a spark-gap switch type pulse power supply (0.5 kJ/pulse) and a 3 L stainless steel reactor with eccentrically configured 5 mm o.d. rod-to-rod electrodes. The optical emission spectrum from plasma was measured during the discharge period by an optical spectrometer. From the optical spectrum, generation of hydrogen, oxygen, ozone and OH as well as UV emissions were observed during the discharge and afterglow periods. Transients of seven gaseous compounds (CO2, CO, NO, NO2, SO2, H2S and CxHy) were measured during the PAED treatment period. It was found that the accumulated concentrations of CO, H2S, NO, SO2 and CxHy increase with increasing PAED treatment time. Results obtained also seem to suggest that the organic, sulfur and nitrate compounds in contaminated stormwater were degraded into gaseous by-products during the PAED treatment process.
Keywords—Pulsed arc electrohydraulic discharge, stormwater treatment, gaseous by-products