Resumen:
Industrial wastewater containing effluents from 190 factories located at an industrial park in Toluca State,
Mexico, was subjected to galvanic (GT), galvanic Fenton (GF), and hydrogen peroxide treatments to remove
organic matter. The galvanic system uses iron-copper electrodes to produce Fe2+ in situ. For the GF system,
hydrogen peroxide was applied to produce hydroxyl radicals. The GF system does not require energy, unlike the
analogous electro-Fenton system, and, in fact, it is possible to generate an electric current (∼220 mV) from the
chemical reactions. A synergistic effect was observed with GF treatment at pH 2.8 and a H2O2/Fe2+ ratio of 19:1
(i.e. 7840 mg H2O2/L and 408 mg Fe2+/L), leading to high removal percentages for color (76%), soluble chemical
oxygen demand (71%), and total organic carbon (79%), while degradations of 43% and 48% were
achieved for biochemical oxygen demand and nitrates, respectively.
Fluorescence and IR spectroscopy analyses of raw and treated wastewater samples were performed with the
aim of establishing the anthropic origin of the dissolved organic matter. Fluorescence spectroscopy showed that
GF treatment eliminated the anthropogenic organic matter associated with aromatic groups and proteins, enhanced
effluent biodegradability, did not increase toxicity, and reduced the sub-lethal effects observed for lettuce
radicles. Most importantly, the removal efficiencies of GF treatment were comparable with those of analogous
electrochemical advanced oxidation processes based on Fenton reactions.
