AWWA WQTC63990

The occurrence of pharmaceutically active compounds (PhACs) in drinking water sources worldwide raises health concerns and the removal of these compounds by drinking water treatment processes is not well understood. The overall objective of this study was to determine the effectiveness of ion exchange (IX) technology in removing trace anionic organic compounds in the presence of competing anionic organic compounds, including natural organic matter (NOM), wastewater effluent organic matter (EfOM) and inorganic anions (e.g., sulfate, SO₄^2-), from wastewater impacted drinking water sources. Target compounds selected for this work are the hydrophilic anionic PhACs ibuprofen (IBP) and diclofenac (DCF). Both kinetics and equilibrium aspects are evaluated. Specific objectives include the evaluation of: the impact of the background organic and inorganic matrix on ion exchange capacity in a batch reactor; kinetic limitations to maximum ion exchange capacity; and, single use and multiple reuse ion exchange resins efficiency. In this study, IBP removal rate at high initial concentration (C0 = 20 µg/L) was a little greater than that at low initial concentration (C0 = 0.1 µg/L). The IBP removal kinetics were fast during the first cycle for both low and high initial concentrations, but they became slower as the number of IX resin reuse cycles increased. In the case of IBP, the resin capacity was significantly reduced due to repeated use in the presence of 50 mg/L of sulfate, which resulted in 35 % and 13 % IBP removal after 6 hr contact time in 1st and 2nd cycled IX resin reuse, respectively. However, in the case of DCF, sulfate effect was negligible so that 85 % and 79 % DCF removals occurred after 6 hr contact time in 1st and 2nd cycled IX resin reuse, respectively. The IX resin capacity was reduced due to repeated use, which resulted in a decreased from 60 % to 30 % DCF removal after 6 hr contact time going from 1st to 6th cycled IX resin reuse. Sulfate removal percent was reduced from 97 % to 60 % after 3 hr contact time at 1st to 6th cycled IX resin reuse. The presence of NOM did not cause any significant difference in IBP removal percentage. A higher pH increased IBP removal rates by the IX resins. Includes table, figures.