Treatment of effluents from wool dyeing process by photo-Fenton at solar pilot plant

Abstract

The decolourization and mineralization of simulated wastewaters from wool dyeing tanks wereinvestigated by Fenton and photo-Fenton processes. Yellow, red and blue dyebaths with azo-type andanthraquinone dyes and additives were selected as colored effluents. Photo-Fenton reaction was muchmore efficient than the respective dark reaction under identical experimental conditions. The effect ofH2O2and Fe(II) dosage and fractional or initial addition of these reagents on the photo-mineralizationprocesses were studied and the optimal conditions found. Experiments at a pilot plant based oncompound parabolic collectors (CPCs) confirmed that, under optimal conditions, 100% of color removalwas obtained requiring low accumulated energy. No toxic effects on marine bacteriaVibrio fischeriwereobserved at the end of photo-Fenton treatment for all studied effluents. High concentrations of sodiumacetate are used as additive in the wool dying process. HPLC and TOC analysis of the effluents after photo-Fenton process confirmed that the remaining organic carbon is due to the presence of acetates. Theobtained results showed the feasibility of photo-Fenton process to achieve suitable water qualities forinternal reuse.