“…This agrees with that reported by Amat et al, [24] and Sirtori et al, [10] who found in a similar study with different types of compounds that the detoxification of wastewater was obtained when the removal of the active recalcitrant elements by means of the oxidation pro- cess was done, indicating that the greater part of the toxicity of the mixture must be attributed to these compounds and that the by-products of the oxidation do not have inhibitory effects on the microorganisms present in sludge. The evidence provided by HPLC detection of Diuron and 2,4-D suggests that the photo-Fenton process rapidly removes these toxic compounds, transforming them into innocuous molecules; furthermore, an accumulation of toxic intermediates does not occur because they are also effectively degraded during the photo-Fenton process.…”