Integration of treatment technologies with Fenton reagent for laboratory effluent remediation

Integração de tecnologias de tratamento com reagente de Fenton para remediação de efluente laboratorial

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.

Keywords:
coagulation/flocculation; cosmetics; textile dyes.