TOC-removal and degradation of pollutants in leachate using a thin-film photoreactor

In this paper, a pilot plant is presented providing the treatment of low volume, high ionic strength wastewaters by advanced oxidation processes, such as UV/O3, UV/H2O2 and UV/O3/H2O2. The plant is equipped with a bubble column to dissolve gaseous ozone and a special designed thin-film photoreactor, which enables the photoinitiated degradation of organic compounds of high optical density without any contact to the radiation source. The thin-film apparatus was applied to model solutions containing humic acid in order to remove the TOC in dependence on the operating conditions. In addition, a leachate of a waste landfill has been treated containing high concentrations of toxic compounds, e.g. chlorinated phenols, polyaromatic hydrocarbons, polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and dibenzo-p-furans. The application of UV/O3 has been proved to be an effective technique for the treatment of leachate resulting in degradation ratios of 100% for both phenols and hydrocarbons, 23–96% for biphenyls and at least 74% for dioxins and furans.