A Large-Scale Study Toward a Hybrid Treatment Approach for High-Strength Polyester Wastewater: A Computational and Experimental Study

Abstract

This investigation deals with treating a high-strength wastewater with a high chemical oxidation demand (COD) of 110,000 (mg O₂/L) generated by industrial polyester plants through polycondensation reactions. The wastewater is characterized by GC–MS, zeta potential, COD, pH, and so forth. Hybrid strategies combining treatment methods, including distillation, advanced oxidation processes (photocatalysis: TiO₂ + UV, H₂O₂, ozone, KMnO₄, and electrical current), physical filtration, and carbon-active adsorption, are employed. The findings demonstrate that oxidation via KMnO₄ or H₂O₂ leads to a COD removal of 60%, while filtration and other oxidation methods suffer from the limitation of removal efficiency. A hybrid approach combining one-step distillation and carbon-active adsorption is introduced to gain an efficiency of 95%. The GC–MS analysis of the treated wastewater demonstrates that the reactive contaminants disappear through the esterification/transesterification reactions during treatment. The solubility parameter ($\delta$) calculated by molecular dynamic simulation indicates that pollutants with high $\delta$ (18–19 (MPa)^0.5) (e.g., tetrahydrofuran-2-methyl) are the major contributors to the treated wastewater, whereas compounds with lower $\delta$ (8–13 (MPa)^0.5) (e.g., 1-Heptene, 2-methyl-) are adsorbed on the carbon-active surface thermodynamically. Consequently, this attempt offers an insight into the nature of polyester wastewater and an integrated low-cost approach to treat this challenging effluent to ensure long-term environmental sustainability.