Combined chemical and biological oxidation of penicillin formulation effluent [An article from: Journal of Environmental Management]

This digital document is a journal article from Journal of Environmental Management, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Antibiotic formulation effluent is well known for its important contribution to environmental pollution due to its fluctuating and recalcitrant nature. In the present study, the chemical treatability of penicillin formulation effluent (average filtered COD"o=830mg/l; average soluble COD"o=615mg/l; pH"o=6.9) bearing the active substances penicillin Amoxicillin Trihydrate (C"1"6H"1"9N"3O"5S.3H"2O) and the @b-lactamase inhibitor Potassium Clavulanate (C"8H"8KNO"5) has been investigated. For this purpose, the penicillin formulation effluent was subjected to ozonation (applied ozone dose=2500mg/(lxh)) at varying pH (2.5-12.0) and O"3+H"2O"2 (perozonation) at different initial H"2O"2 concentrations (=2-40mM) and pH 10.5. According to the experimental results, the overall Chemical Oxygen Demand (COD) removal efficiency varied between 10 and 56% for ozonation and 30% (no H"2O"2) and 83% (20mM H"2O"2) for the O"3+H"2O"2 process. The addition of H"2O"2 improved the COD removal rates considerably even at the lowest studied H"2O"2 concentration. An optimum H"2O"2 concentration of 20mM existed at which the highest COD removal efficiency and abatement kinetics were obtained. The ozone absorption rate ranged between 53% (ozonation) and 68% (perozonation). An ozone input of 800mg/l in 20min was sufficient to achieve the highest BOD"5/COD (biodegradability) ratio (=0.45) and BOD"5 value (109mg/l) for the pre-treated penicillin formulation effluent. After the establishment of optimum ozonation and perozonation conditions, mixtures of synthetic domestic wastewater+raw, ozonated and perozonated penicillin formulation effluent were subjected to biological activated sludge treatment at a food-to-microorganisms (F/M) ratio of 0.23mg COD/(mg MLSSxd), using a consortium of acclimated microorganisms. COD removal efficiencies of the activated sludge process were 71, 81 and 72% for pharmaceutical wastewater containing synthetic domestic wastewater mixed with either raw, ozonated or perozonated formulation effluent, respectively. The ultimate COD value obtained after 24-h biotreatment of the synthetic domestic wastewater+pre-ozonated formulation effluent mixture was around 100mg/l instead of 180mg/l which was the final COD obtained for the wastewater mixture containing raw formulation effluent, indicating that pre-ozonation at least partially removed the non-biodegradable COD fraction of the formulation effluent.