LARGE-SCALE DEVELOPMENT OF A LIGHT-ENHANCED FENTON REACTION BY OPTIMAL EXPERIMENTAL-DESIGN

Photochemical advanced oxidation processes (AOP) for the treatment of waste waters containing biocidal or non-biodegradable organic compound s rely mainly on the production of a potent oxidizing agent, the hydro xyl radical, The Fenton's reagent, a mixture of hydrogen peroxide and ferrous ion, represents one possible source of hydroxyl radicals and i t has been shown recently that degradation rates may be significantly enhanced by UV/visible irradiation. In this context, we have investiga ted the feasibility of a large scale application of the light-enhanced Fenton reaction to the treatment of a highly contaminated industrial waste water containing toxic aromatic amines (dimethyl anilines or xyl idines) as the main pollutants. Following preliminary laboratory tests performed on the model compounds, 2,4- and 3,4-xylidines (200 mg/L, 2 L), experimentation on the industrial waste water at a large scale le vel (3000 mgC/L, 500 L) has been carried out using the experimental de sign methodology for the simulation and the evaluation of the effects of the two critical factors, hydrogen peroxide and ferrous ion concent rations. The light-enhanced Fenton reaction has been proven to be a mo st effective treatment process under acidic conditions and might be an alternative to adsorption of xylidines on activated carbon as used at present. (C) 1997 IAWQ. Published by Elsevier Science Ltd.