LANDFILL LEACHATE TREATMENT BY A PHOTOASSISTED FENTON REACTION

A combination of the classical Fenton reaction (Fe(II)+H2O2) with UV l ight, the photoassisted Fenton reaction, has been investigated for the treatment of landfill leachate. The investigation has been carried ou t with an experimental set-up to establish the optimal treatment condi tions. The degradation rate of organic pollutants is strongly promoted by the photoassisted Fenton reaction. The degradation rate depends on the amount of H2O2 and Fe(II) added, pH value, and radiation intensit y. At a specific energy input of 80 kW m(-3) the oxidation rate was in creased to six times the rate without radiation (0 kW m(-3)). At the h igher radiation intensity of 160 kW m(-3) the degradation rate was abo ut two times faster than at that of 80 kW m(-3). Due to the regenerati on of the consumed Fe(II) ions through the irradiation, the amount of ferrous salt to be added can be remarkably reduced. The optimum condit ions were obtained with 1.0 x 10(-3) mol l(-1) Fe(II) added, a pH valu e of 3, and a molar ratio of COD : H2O2 = 1:1. At a COD volume loading of less than 0.6 kg m(-3) h(-1), a COD degradation of more than 70% c ould be obtained with an energy input of 80 kW m(-3). (C) 1997 IAWQ. P ublished by Elsevier Science Ltd.