Treatment of antibiotic formulation wastewaters by fenton process

Pharmaceuticals formulation plants have a variety of wastewater sources. A significant part of these wastewaters can be directly conducted to central biological treatment. Among the wastewater groups that need a pretreatment, antibiotic wastewaters require a special attention due to their toxicity to biological treatment and low biodegradability. In this study, pretreatment of antibiotic formulation wastewaters by Fenton oxidation process was experimentally investigated. Three different antibiotic formulations, all having common use, were selected. The basic formulation of the antibiotics used were; cefuroxime axetil, ceftriaxone and sulfisoxazole. Strength of all three samples was similar and around 1000 mg/L COD. Fenton oxidation proved very effective on all samples. Optimum conditions of oxidation were found as; pH 2, Fe ²+/H₂O₂ of 0.49 g/g and H₂O ₂/TOC ratio varying from 2 to 6 g/g. High degree of conversion was completed within 2 hours. The process provided flocculation of particulate organics, oxidation and mineralization. 80-93% COD removals in all three samples were achieved. A marked increase in biodegradability could only be obtained after a high degree of COD removal. The ceftriaxone sample was very resistant to biodegradation. A satisfactory level of biodegradation could be achieved after 80% COD removal indicating that for such cases Fenton process can be conceived as a final treatment rather than a pretreatment.