Fenton oxidation and biological treatment on pharmaceutical wastewater

Due to the wide variety of products produced in a drug manufacturing plant, pharmaceutical industry wastewater is a wastewater that is not amenable to conventional biological treatment. In this study, this wastewater was chemically pretreated using Fenton's reagent, since the initial values of the biokinetic coefficients before Fenton indicated that this wastewater could not be biologically treated. A factorial experimental procedure was designed in order to examine the influence of Fenton's pretreatment on biological oxidation. Although the Fenton oxidation process was not very effective, the overall efficiency mounted up to almost 80% in some cases. The optimum experimental conditions for the oxidation of pharmaceutical wastewater were found to be the following: FeSO(4)center dot 7H(2)O concentration 2 g.L(-1), H(2)O(2) concentration 2 mL.L(-1). It was proved that after the Fenton process, the substrate was rendered significantly more biodegradable since the maximum specific uptake rate Ka,, was increased from 1,76 to 3,14 gCOD.gVSS(-1.)d(-1), whereas the inhibitory coefficient Ks was decreased from 3752 to 732 mg.L(-1). Conclusively, Fenton oxidation could be a feasible method for the pretreatment of pharmaceutical wastewater.