Using ultraviolet absorbance and color to assess pharmaceutical oxidation during ozonation of wastewater

Eric C. Wert, Fernando L. Rosario-Ortiz, Shane A. Snyder

Research output: Contribution to journalArticlepeer-review

108 Scopus citations


The reduction of ultraviolet (UV) absorbance at 254 nm (UV254) and true color were identified as appropriate surrogates to assess the oxidation of six pharmaceuticals (i.e., carbamazepine, meprobamate, dilantin, primidone, atenolol, and iopromide) during ozonation of wastewater. Three tertiary-treated wastewaters were evaluated during oxidation with ozone (O3) and O3 coupled with hydrogen peroxide (O3/H2O 2). The correlation between pharmaceutical oxidation and removal of UV254 was dependent upon the reactivity of each specific compound toward ozone, as measured by the second-order rate constant (k″ O3). Oxidation of compounds with k″O3 > 10 3 M-1 s-1 correlated well (R2 > 0.73) with UV254 reduction between 0-50%. Oxidation of compounds with apparent k″O3 < 10 M-1 s-1 resulted primarily from hydroxyl radicals and correlated well (R2 > 0.80) with the UV254 reduction of 15-65%. The removal of true color also correlated well (R2 > 0.85) with the oxidation of pharmaceuticals during the ozonation of two wastewaters. These correlations demonstrate that UV254 reduction and true color removal may be used as surrogates to evaluate pharmaceutical oxidation in the presence or absence of dissolved ozone residual during advanced wastewater treatment with O3 or O 3/H2O2. The use of online UV254 measurements would allow wastewater utilities to optimize the ozone dose required to meet their specific treatment objectives.

Original languageEnglish (US)
Pages (from-to)4858-4863
Number of pages6
JournalEnvironmental Science and Technology
Issue number13
StatePublished - Jul 1 2009

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry


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