Contaminants of emerging concern (CEC) are increasingly being detected in drinking water supplies and treated wastewater effluent, which may pose risk on human and ecological health. The transformation products of these chemicals during and after the water treatment processes might have greater cytotoxicity than the parent compounds. Thus, UV based-advanced oxidation processes (UV-AOPs) were used to efficiently remove CECs in water reuse applications. Specifically, low-pressure (LP)-UV254nm/H2O2 and LP-UV254nm/NO3− were investigated for the degradation of selected CECs. For the UV254nm/H2O2 process, LP-UV/H2O2 and LED-UV/H2O2 were compared for the degradation of a mixture of five CECs, including diclofenac (DCF), ibuprofen (IBP), triclosan (TCS), bisphenol A (BPA), and estrone (E1). Contributions from UV irradiation, H2O2 oxidation, and hydroxyl radical-oxidation to the degradation of each CEC were determined, respectively. For the UV254nm/NO3− process, the different effects of HCO3− on the degradation of eight CECs with different chemical properties were evaluated, including DCF, IBP, TCS, BPA, E1, 17α-ethynylestradiol (EE2), atrazine (ATZ), and carbamazepine (CBZ). The second-order rate constants of carbonate radical with selected CECs were measured. Contributions from UV photolysis and oxidation processes (induced by reactive nitrogen species, &lt;span style="font-size:10.8333px"&gt;hydroxy radical&lt;/span&gt;, and carbonate radical) to the CEC degradation in UV/NO3− and UV/NO3−/HCO3− were evaluated, respectively. Additionally, transformation products generated during the decomposition of selected CECs in UV/H2O2 and UV/NO3− were measured by Q-TOF UHPLC/MS, respectively. Moreover, cytotoxicity and estrogen receptor (ER)-binding activity analysis for the treated water by UV/H2O2 and UV/NO3− were carried out, respectively, evaluating the applicability of these two proposed treatment methods. Specifically, Vm7Luc4E2 and CYP1A-BLA LS180 cells were both used for cytotoxicity studies. CYP1A-BLA LS180 cells were used to evaluate Aryl hydrocarbon Receptor (AhR) activity and Vm7Luc4E2 was used for Estrogen Receptor (ER) activity measurements. Finally, field water samples from Orange County Water District’ Groundwater Replenishment System (GWRS) were utilized as reaction matrices with spiked additions of chemicals to assess the applicability of these two proposed treatment methods, UV/H2O2 and UV/NO3−.

Degradation kinetics and cytotoxicity analysis of contaminants of emerging concern treated by UV/H2O2 and UV/NO3−

2019 Spring National Meeting

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