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Techno-economical evaluation of coupling ionizing radiation and biological treatment process for the remediation of real pharmaceutical wastewater

Changotra, Rahil, Rajput, Himadri, Guin, Jhimli Paul, Khader, Shaik Abdul, Dhir, Amit
Journal of cleaner production 2020 v.242 pp. 118544
absorbed dose, acclimation, activated sludge, biological treatment, chemical oxygen demand, cities, coagulation, cytotoxicity, effluents, industrial wastewater, inorganic compounds, ionizing radiation, irradiation, manufacturing, microorganisms, organic compounds, oxidants, pH, pharmaceutical industry, radiolysis, raw materials, remediation, resource management, wastewater treatment
Pharmaceutical manufacturing industries produce a vast range of substances by using organic and inorganic compounds as raw material thereby gives rise to huge volume of toxic and complex organic liquid effluents comprised of high levels of dissolved solids. High and low strength wastewater streams originating from manufacturing unit often contains different types of contaminants, including organic compounds which can be difficult to treat with conventional methods of treatment. In this study, the sequential treatment process of coagulation, electron beam (E-beam) irradiation and biological treatment was employed on real pharmaceutical industrial wastewater to study the impact of combined treatment on remediation and detoxification of the wastewater. Combined treatment was performed on low (LOSW) and high (HOSW) organic strength wastewater collected from representative pharmaceutical industry. Operational parameters like pH, absorbed dose and use of oxidants were systematically investigated to achieve the enhanced treatment of wastewater streams using E-beam irradiation. Biological treatment was carried out using activated sludge process at laboratory-scale reactor by utilizing acclimatized consortia in the experiments. Sequential hybrid coagulation, E-beam irradiation and biological treatment lead to synergistic degradation and detoxification of both the recalcitrant wastewater streams with overall chemical oxygen demand (COD) removal of 94% and 89% for LOSW and HOSW, respectively. Cytotoxicity assessment revealed that the combined treatment of wastewater was effective in eliminating the toxicity when tested against the selected microorganisms. The treatment cost of E-beam radiolysis alone, biological treatment alone and E-beam + biological treatment for LOSW was found to be 0.50, 2.35 and 2.85 USD m⁻³; whereas, for HOSW, it was found to be 0.67, 0.7 and 1.37 USD m⁻³, respectively. The overall cost of the set-up of an E-beam unit and the treatment cost for real pharmaceutical wastewater was evaluated to establish the applicability of the E-beam technology at industrial scale. The feasibility of E-beam irradiation for wastewater remediation may ensure future smart cities with sustainable resource management.