Research On Pretreatment By Fenton And UV-Fenton Processes For Bio-pharmaceutical Wastewater

Lincomycin with low butanol content wastewater and clindamycin phosphate wastewater from Pukang Pharmaceutical Co., Ltd. were choosed as the research objects, and with COD removal as the main index the experiment research was carried as following. (1) For lincomycin with low butanol content wastewater, first, level of impact factors on Fenton process was determined by orthogonal test; and the optimum conditions of Fenton process were determined by single factor test; and treatment effect of UV-Fenton process under the optimum conditions of Fenton process was studied; and COD degradation kinetics under the optimum conditions of Fenton process was studied; and then treatment effect of Fenton process combined coagulation was studied; finally, aerobic biological treatment for the raw wastewater and the effluent of Fenton process under the optimum conditions was carried to analyze variation of wastewater biodegradability. (2) Comparative study of pretreatment effect of Fenton and UV-Fenton processes for clindamycin phosphate wastewater was carried. first, level of impact factors on Fenton process was determined by orthogonal test; and the optimum conditions of Fenton process were determined by single factor test; and then treatment effect of UV-Fenton process under the optimal conditions of Fenton process was studied; and then treatment effect of Fenton process+coagulation and coagulation+Fenton process was studied; finally, anaerobic gas production test for the raw wastewater and the effluent of UV-Fenton process under the optimum conditions was carried to analyze variation of wastewater biodegradability.The optimal conditions of Fenton process pretreating lincomycin with low butanol content wastewater were that:dosage of FeSO4 and H2O2 was 7.55 mmol/L and 0.04 mol/L, respectively, initial pH was 5, and reaction time was 90 min. Under the optimal conditions, COD removal effiency reached 63.03%. Variation of pH was similar to COD in Fenton reaction system, which indicated pH of the reaction system could reflect the degree of COD degradation. The trend of pH of the reaction system dropping as time demonstrated that organic acids were produced during the reaction. Based on kinetics of single substrate, COD degradation kinetics equation of lincomycin with low butanol content wastewater was established, and fitting results showed that the equation could better reflect the course of COD degradation. The effect of coagulation using PAM for the effluent of Fenton process was not obvious.ΔCOD/COD of the raw wastewater and the effluent of Fenton process by aerobic biological treatment was 0.57 and 0.69. So, it could be seen that wastewater biodegradability was improved after pretreatment by Fenton process.The optimal conditions of Fenton process pretreating clindamycin phosphate wastewater were that:dosage of FeSO4 and H2O2 was 0.037 mol/L and 0.102 mol/L, respectively, initial pH was 4, and reaction time was 70 min. Under the optimal conditions COD removal effiency reached 43.07%, about 5.5% lower than UV-Fenton process. COD removal effect of UV-Fenton process+coagulation and coagulation+UV-Fenton process was not significant, compared to UV-Fenton process alone. None methane produced in anaerobic gas production test of the raw wastewater within 24 h, while 95 mL methane produced in anaerobic gas production test of the effluent of UV-Fenton process within 24 h, which showed that UV-Fenton process could improve wastewater biodegradability.Fenton and UV-Fenton processes treating clindamycin phosphate wastewater was less effective, and large reagents dosage was needed. Partly because clindamycin phosphate residues in wastewater hydrolyzed to H2PO4-, complexing Fe2+ and Fe3+, which reduced catalytic activity of Fe2+. This conclusion was verified by comparing the phenomenon between the former and adding Fenton reagent to phosphoric acid and potassium dihydrogen phosphate solution.This study would provide some theoretical support for the pratical application of Fenton and UV-Fenton processes, which has some practical significance in treating bio-pharmaceutical wastewater.