Hybrid coagulation, gamma irradiation and biological treatment of real pharmaceutical wastewater

The present study aimed towards the utilization of hybrid approaches for the effective treatment of real pharmaceutical industry wastewater. The focus was to treat pharmaceutical wastewater with low (LSW) and high organic strength (HSW), which was collected from the effluent treatment plant of the representative bulk pharmaceutical manufacturing unit. The hybrid approach included coagulation treatment, biological treatment and gamma irradiation which were employed individually and in sequence to determine the most appropriate treatment sequence for effective remediation of real pharmaceutical wastewater. To compare process performance, gamma-irradiation was employed as pre-treatment and post-treatment stage to biological treatment. To achieve the enhanced removal efficiency using gamma irradiation treatment, oxidant like H2O2 and persulfate ions S2O82- were used and optimized for LSW and HSW. Results indicated that use of H2O2 lead to enhanced COD and TOC removal efficiency when compared to S2O82-. The sequential approach of coagulation, gamma irradiation and biological treatment accounts for the synergistic degradation and detoxification of recalcitrant pharmaceutical wastewaters, and lead to overall 92.7% +/- 2.3% and 90.2% +/- 2.9% of COD removal of LSW and HSW, respectively. The pre-treatment using gamma-irradiation enabled effective treatment, achieving 58.7% +/- 3.2% COD and 80.4% +/- 2.1% TOC removal efficiencies for LSW; whereas 62.0% +/- 2.9% COD and 71.0% +/- 2.7% TOC removal efficiencies were achieved for HSW. Cytotoxicity assessment and cost analysis of the treatment process were examined and analyzed.