ABSTRACT
The study examined combined photo-Fenton-SBR treatment of an antibiotic wastewater containing amoxicillin and cloxacillin. Optimum H(2)O(2)/COD and H(2)O(2)/Fe(2+) molar ratio of the photo-Fenton pretreatment were observed to be 2.5 and 20, respectively. Complete degradation of the antibiotics occurred in one min. The sequencing batch reactor (SBR) was operated at different hydraulic retention times (HRTs) with the wastewater treated under different photo-Fenton operating conditions (H(2)O(2)/COD and H(2)O(2)/Fe(2+) molar ratio). The SBR performance was found to be very sensitive to BOD(5)/COD ratio of the photo-Fenton treated wastewater. Statistical analysis of the results indicated that it was possible to reduce the Fe(2+) dose and increase the irradiation time of the photo-Fenton pretreatment. The best operating conditions of the combined photo-Fenton-SBR treatment were observed to be H(2)O(2)/COD molar ratio 2, H(2)O(2)/Fe(2+) molar ratio 150, irradiation time 90 min and HRT of 12h. Under the best operating conditions, 89% removal of sCOD with complete nitrification was achieved and the SBR effluent met the discharge standards.
Subject(s)
Amoxicillin/analysis , Anti-Bacterial Agents/analysis , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/analysis , Water Purification/methods , Biodegradation, Environmental , Bioreactors , Cloxacillin/analysis , Equipment Design , Hydrogen Peroxide/chemistry , Hydrolysis , Iron/chemistry , Photochemistry/methodsABSTRACT
The study examined the implementation of artificial neural network (ANN) for the prediction and simulation of antibiotic degradation in aqueous solution by the Fenton process. A three-layer backpropagation neural network was optimized to predict and simulate the degradation of amoxicillin, ampicillin and cloxacillin in aqueous solution in terms of COD removal. The configuration of the backpropagation neural network giving the smallest mean square error (MSE) was three-layer ANN with tangent sigmoid transfer function (tansig) at hidden layer with 14 neurons, linear transfer function (purelin) at output layer and Levenberg-Marquardt backpropagation training algorithm (LMA). ANN predicted results are very close to the experimental results with correlation coefficient (R(2)) of 0.997 and MSE 0.000376. The sensitivity analysis showed that all studied variables (reaction time, H(2)O(2)/COD molar ratio, H(2)O(2)/Fe(2+) molar ratio, pH and antibiotics concentration) have strong effect on antibiotic degradation in terms of COD removal. In addition, H(2)O(2)/Fe(2+) molar ratio is the most influential parameter with relative importance of 25.8%. The results showed that neural network modeling could effectively predict and simulate the behavior of the Fenton process.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Hydrogen Peroxide/chemistry , Iron/chemistry , Oxygen/analysis , Algorithms , Artificial Intelligence , Hydrogen-Ion Concentration , Models, Chemical , Models, Statistical , Neural Networks, Computer , Neurons , Reproducibility of Results , Solutions , WaterABSTRACT
The study examined the effect of operating conditions (zinc oxide concentration, pH and irradiation time) of the UV/ZnO photocatalytic process on degradation of amoxicillin, ampicillin and cloxacillin in aqueous solution. pH has a great effect on amoxicillin, ampicillin and cloxacillin degradation. The optimum operating conditions for complete degradation of antibiotics in an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin and cloxacillin, respectively were: zinc oxide 0.5 g/L, irradiation time 180 min and pH 11. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred and COD and DOC removal were 23.9 and 9.7%, respectively. The photocatalytic reactions under optimum conditions approximately followed a pseudo-first order kinetics with rate constant (k) 0.018, 0.015 and 0.029 min(-1) for amoxicillin, ampicillin and cloxacillin, respectively. UV/ZnO photocatalysis can be used for amoxicillin, ampicillin and cloxacillin degradation in aqueous solution.
Subject(s)
Amoxicillin/chemistry , Amoxicillin/radiation effects , Ampicillin/chemistry , Ampicillin/radiation effects , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/radiation effects , Cloxacillin/chemistry , Cloxacillin/radiation effects , Medical Waste/analysis , Ultraviolet Rays , Zinc Oxide/chemistry , Biodegradation, Environmental , Catalysis , Chromatography, High Pressure Liquid , Hydrogen-Ion Concentration , Kinetics , Photochemistry , Solutions , Spectrophotometry, Ultraviolet , Time Factors , Water/chemistryABSTRACT
The study examined degradation of the antibiotics amoxicillin, ampicillin and cloxacillin in aqueous solution by the photo-Fenton process. The optimum operating conditions for treatment of an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and cloxacillin, respectively was observed to be H(2)O(2)/COD molar ratio 1.5, H(2)O(2)/Fe(2+) molar ratio 20 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred in 2 min. Biodegradability (BOD(5)/COD ratio) improved from approximately 0 to 0.4, and COD and DOC degradation were 80.8 and 58.4%, respectively in 50 min. Photo-Fenton treatment resulted in the release and mineralization of organic carbon and nitrogen in the antibiotic molecule. Increase in ammonia and nitrate concentration, and DOC degradation were observed as a result of organic carbon and nitrogen mineralization. DOC degradation increased to 58.4% and ammonia increased from 8 to 13.5mg/L, and nitrate increased from 0.3 to 14.2mg/L in 50 min.
