Advanced oxidation processes (AOPs) such as ozonation or ultraviolet light (UV) coupled with H2O2 (UV/H2O2) have been proposed as important treatment alternative for improvement of recycled water qualities. Potential applications of UV c-band light-emitting diodes (UVC-LED) in water treatments have also caused attentions due to its advantages such as wavelength-specific UV light and low energy consumptions. This study assessed the potential AOP applications with low pressure UV (LPUV/H2O2) and UVC-LED/H2O2 in treating biologically treated wastewater elffluents for their efficacy in derading the organic contents in treated water for potential reuses. After LPUV/H2O2 oxidation and disinfection byporduct formation potential (DBPFP) tests, the results showed that LPUV lamps (254 nm) combined with H2O2 can effectively dissociate the H2O2 to produce hydroxyl radicals for mineralization of the organic matter in biologically treated wastewater effluents. Higher oxidation efficiency was obtained when the oxidation capacity of LPUV was increased in the system. With the increased LPUV/H2O2 treatment time, the DBPFP increased in the beginning stage of oxidation. After reached the maximum DBPFP, the trihalomethane (THM) precursors decrease after 20 minutes of LPUV/H2O2 oxidation; however, reduction of haloacetic acid (HAA) precursors needs more than 30 minutes of photolysis. The profiles of DBP precursors during the LPUV/H2O2 processes showed that the proportion of THM precursors was higher than that of HAA. After a long photolysis time, the majority of DBP precursors in LPUV/H2O2 treated water belong to the category of THMs precursors. Due to the much lower energy available from UVC-LED (260 nm, 1 watt), a lower degradation rate of organic matter was obtained when UVC-LED/H2O2 oxidation was conducted. However, similar trends were obtained for both organic matter degradations and corresponding DBPFP tests when the results of UVC-LED/H2O2 and LPUV/H2O2 oxidations were normalized to their electricity consumptions. Since the current energy efficiency of UVC-LED is relatively low (mostly less than 10%), it is expected that the treatment efficiency and energy consumption of UVC-LED will be greatly improved when the efficiency of energy transformation of UVC-LED is improved.

Advanced oxidation of recycled water with UV/H2O2: Comparison of treatment efficiencies with UVC-LED and LPUV

2019 Fall National Meeting

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