Integration of treatment technologies with Fenton reagent for laboratory effluent remediation

Abstract

This study investigated of the potential value of the integration of the coagulation/flocculation, Advanced Oxidation Processes (AOP) (Fenton reagent) and slow sand filtration technologies, with the aim of treating laboratory wastewater. The treatment system was designed in laboratory scale through coagulation/flocculation. It involved the use of Jar Test equipment with a sequence of two rotational phases: fast mixes to 300 rpm for 20 seconds and slow mixes to 30 rpm for 6 minutes and 10 seconds, with the addition of anionic polymer and sedimentation for 60 minutes at ambient temperature. In the treatment via Fenton reagent, two rotational phases were used: rapid mixing at 300 rpm for 20 seconds with the addition of iron (Fe2+) and slow mixing at 30 rpm for 6 minutes and 10 seconds with the addition of hydrogen peroxide, followed by 60 minutes of sedimentation at ambient temperature. A cylindrical tank of polyvinyl chloride, sands and non-woven synthetic fabrics were used in the slow filtration. The filtration rate adopted was 3 m3 m-2 d-1 with a hydraulic retention time of 264 minutes. The best concentrations of chemical reagents used in the treatments were: 0.80 mg L-1 of polymeric anionic, 200.00 mg L-1 of H2O2 and 13.00 mg L-1 of total soluble iron. The integration of the treatment technologies made it possible to achieve a removal rate of 75.27% of COD and 94.12% of total phenols. Furthermore, the conjugation of the processes allowed the removal of 87.58% of TOC.