Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Treatment of biorecalcitrant compounds in saline wastewater by photo-Fenton

A coupled solar photocatalytic-biological system has been developed to enhance the biodegradability and complete mineralization of a biorecalcitrant industrial compound, methylphenylglycine, dissolved in seawater at 500 mg L-1. The pollutant was completely degraded by a solar photo-Fenton treatment plant made up of Compound Parabolic Collector (CPC) units. The catalyst concentration employed was 20 mg L-1 of Fe2+ and the H2O2 concentration was kept in the range of 200-500 mg L-1. A Zahn-Wellens (Z-W) test applied to photo-treated samples demonstrated that intermediates produced within a short time of starting the photo-Fenton process were biodegradable.

Consequently, the photocatalytic and biological processes were combined. Biodegradable compounds generated during the preliminary oxidative process were biologically mineralised in an aerobic Immobilised Biomass Reactor (IBR), filled with propylene Pall Ring supports colonized by activated sludge. Almost total mineralization (90% overall Total Organic Carbon removed) was attained in the combined treatment system. Moreover, nitrification and denitrification phenomena were also observed.

This result indicates that a combined solar photocatalytic-biological process is an effective approach for the treatment of biorecalcitrant pollutants present in seawater. A preliminary study estimated the cost per m3 of effluent treated between 7 and 10 (30% and 70 % capital and operational costs, respectively).

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