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Evolution of Absorbance Spectra of Ozonated Wastewater and Its Relationship with the Degradation of Trace-Level Organic Species

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journal contribution
posted on 15.08.2010 by Venkateswarlu Nanaboina, Gregory V. Korshin
This study examined the evolution of absorbance spectra of wastewater ozonated using varying initial ozone concentrations or treatment times; concomitant changes of concentrations of trace-level pharmaceuticals were also quantified. The absorbance of ozonated wastewater decreased due to the degradation of chromophores in effluent organic matter (EfOM). The relative decrease of absorbance (ΔA/A0) ranged from <30% for λ < 250 nm to >80% for λ > 320 nm. The removal of atenolol, carbamazepine, DEET, diclofenac, gemfibrozil, ibuprofen, iopromide, naproxen, propranolol, sulfamethoxazole, trimethoprim, and p-chlorobenzoic acid was strongly correlated with ΔA/A0 values. The observed features were hypothesized to correspond to the engagement of kinetically distinct groups of EfOM chromophores. Modeling of the evolution of EfOM absorbance and concurrent degradation of trace-level organic species based on this hypothesis confirmed its applicability and utility for practical applications and theoretical exploration.