(353d) Advanced Oxidation of Pharmaceuticals: Preparing for Indirect and Direct Water Reuse

This research addresses two important issues associated with application of advanced oxidation processes (AOPs) for treatment of pharmaceutically active compounds (PhACs) in water reuse scenarios: composition of the background organic matter matrix and residual pharmaceutical activity (i.e., the post-treatment pharmacological activity associated with the target compound and/or its derivatives). Because AOPs are not selective, proper treatment design must consider the characteristic differences between human-impacted organic matter (HIOM), which derives from wastewater treatment plant effluent streams, and natural organic matter (NOM). Furthermore, because it is pharmacological activity, and not parent compound concentration, that threatens the contamination of drinking water resources, research efforts should focus on removing pharmacological activity.

In particular, this research focuses on advanced oxidation, via the peroxone (ozone/hydrogen peroxide) process, of two antibiotic drugs, namely, ciprofloxacin and gemifloxacin. Research tasks include the following: determine removal rates of target PhACs in the presence of varying background organic matter matrices derived from natural and reuse water sources; identify intermediate products that exhibit antibiotic activity; assess whether parent compound removal efficacy is directly proportional to eliminating residual pharmacological activity (RPA) or if intermediate products exert a significant fraction of RPA, which will be determined using a modified minimum inhibitory concentration (MIC) bioassay; develop a technique that can be employed to evaluate and optimize RPA removal from natural and impacted waters while minimizing pharmacologically active intermediates and advanced oxidation by-products.

The overarching goal of this research is development of a generalized strategy for assessing and predicting PhAC treatment efficacy, in terms of RPA removal, as a function of background organic matter matrix, treatment design, and operating parameters.