Studies on the Application of Advanced Oxidation Process for the Treatment of Industrial Wastewater Containing Refractory Toxic Organics From Bulk Drugs Manufacturing Processes

摘要

Industrial wasterwaters containing refractory toxic organics, such as p-anisaldehyde and 2-aminothiophenol from diltiazem hydrochloride (a bulk drug) and dimethylsulfoxide from Ketoconazole (a bulk drug) manufacturing processes were treated by hydroxyl radical oxidation to remove these refractory toxic organics. These compounds impart a high chemical oxygen demand of 70000 mg/L (dimethyl sulfoxide) to 200000 mg/L (p-anisaldehyde) and whereas a COD of 7400 mg/L for 2-aminothiophenol and have pale yellow to dark brown color. However, a H_2O_2 /UV advanced oxidation process was found to effectively treat dimethyl sulfoxide effluent stream with 100% compound degradation and 82% COD reduction; p-anisaldehyde effluent stream with 100% compound degradation and 80% COD reduction whereas for 2-aminothiophenol effluent stream with up to 80% compound degradation and 60% COD reduction at 750 ppm of H_2O_2 dosage and at optimum pH of 7 after about 8 hour irradiation time. The H_2O_2/UV treated effluent stream of p-anisaldehyde, dimethyl sulfoxide and 2-aminothiophenol showed the absence of these refractory toxic compounds as shown by GC analysis. The GC analysis of treated effluent streams also confirmed the degradation of other volatile compounds which might be present in the effluent streams. This degree of treatment is sufficient for further treatment these effluent streams biologically since H_2O_2/UV treatment increased the biodegradability of the treated effluent.