Electrolysis of real leachates from lindane processing industrial dumps

In this work, the electrolytic treatment of the real leachate of an industrial dump that contains a complex mixture of different isomers of hexachlorocyclohexane and other chlorinated hydrocarbons, produced during the ageing of the dump, is studied using different types of electrodes (boron doped diamond, BBD, or mixed metal oxide, MMO). Results demonstrate the effectivity of this technological approach as well as the important effect of the anode material and the irradiation of UVC light. Regarding the first, the choice of BDD coatings lead to a non-selective and extremely efficient degradation of the chlorinated organic compounds (COCs) with a low dependency on the exerted current density. In contrast, MMO coatings exhibit slower and less efficient degradation, with improved degradation results at lower current densities. Regarding the second, as demonstrated in a previous study for the dosing of electrochemically produced hydrogen peroxide, UVC light irradiation not only does not improve but worsen the degradation of the chlorinated hydrocarbons and this is explained by the better predisposition of the target pollutants for being oxidized with molecular oxidant rather than with radicals. This work provides important lessons learned for future applications of the electrochemical technology in the treatment of comparable environmental problems.