Use of ultraviolet irradiation and hydrogen peroxide for the control of solvent contamination in small water utilities

Abstract

The U.S. Environmental Protection Agency has recently regulated several industrial solvents. The treatment technologies available for these contaminants are air stripping or adsorption on granular activated carbon. Both have disadvantages: with air stripping, the off-gases may have to be treated prior to discharge and granular activated carbon must periodically be thermally reactivated. The process being researched is a combination of oxidation and ultraviolet (UV) irradiation. The oxidant to be investigated is hydrogen peroxide (H 2O 2). The general concept is that because H 2O 2 is easy to feed, because UV technology is improving, and because the waters to be treated are low in TOC, the likelihood of unknown oxidant by-products being produced is small, as is the likelihood of fouling of the UV Lamps, and because no waste streams are produced, this would be an attractive treatment possibility for small utilities. Thus far, benzene, 1,2-dichloroethane, 1,1-dichloroethylene, 1,1,1-trichloroethane, trichloroethylene, carbon tetrachloride, and 1,4-dichlorobenzene have been tested at high concentrations in head-space free Teflon® bags in the dark. In addition, benzene, 1,1,1-trichloroethane, trichloroethylene, and carbon tetrachloride have been tested in the presence of UV irradiation with H 2O 2, and the results compared as follows: Compound Total conversion (mg/L/hour) Factor of improvement with UV irradiation dark reaction UV irradiation Trichloroethylene 0.03 30 1000 Benzene 0.12 60 500 1,1,1-Trichloroethane 0.11 13 120 Carbon Tetrachloride 0.02 5 250 Batch test studies will be completed for several other compounds in future research and all the compounds will also be tested under flow-through conditions.