Combining photo-Fenton process with biological sequencing batch reactor for 2,4-dichlorophenol degradation

Abstract

The effect of the photo-Fenton process on biodegradability enhancement of 100 mg.L^-1 aqueous 2,4-dichlorophenol (2,4-DCP) solution has been investigated. An initial concentration of 65 mg.L^-1 H₂O₂ and 10 mg.L^-1 Fe (II) during 35 minutes of irradiation time was sufficient for total 2,4-DCP removal. At these working conditions, biodegradability, measured as BOD₅/COD ratio, was increased from 0 for the original solution up to 0.15. Biological oxidation of photo-Fenton pre-treated solutions was performed in a sequencing batch reactor (SBR). After 32 days of start-up, the reactor was fed with different pre-treated solutions and cycle duration was reduced progressively. TOC removal efficiencies in the SBR went from 30 up to 70%.