APPLICATIONS FOR ADVANCED OXIDATION OF DRINKING WATER USING UV LEDS

Abstract

Advanced oxidation processes (AOPs) have received much attention in recent years as a new technology for drinking water treatment due to their ability to efficiently degrade natural organic matter (NOM). Ultraviolet light-emitting diode (UV-LED) technology is the most ideal light source for AOPs because of their small size and versatility in design. The focus of this research was to investigate the feasibility of UV-LEDs AOPs in drinking water treatment applications by using pilot-scale treated water from the J. Douglas Kline Water Supply Plant (JDKWSP) which draws water from Pockwock Lake. The research directions were mainly categorized as follows: (1) To explore the effects of novel UV-LED AOPs as well as conventional ozone reactions on the transformation of NOM in drinking water. (2) Investigation of changes in the composition of water after AOPs and its association with DBPFP. (3) To compare three AOP technologies including ozone, UV-LEDs/H2O2 and UV-LEDs/Cl2, for the treatment of water from three different locations in the drinking water treatment process. In each experiment, 280nm UV-LEDs were used as the experimental light source to complete the experiments at bench-scale, and the UV fluence was adjusted to 100, 500, and 1,000mJ/cm2 respectively. The overall goal was to help determine the feasibility of UV-LEDs AOPs in water treatment. The results of the research demonstrated that UV-LEDs AOPs at a fluence of 1000mJ/cm2 and 10mg/L H2O2 or Cl2 performed better than 10mg/L ozone alone with regards to reducing the SUVA, indicating the partial oxidation of NOM. In particular, the UV-LEDs/Cl2 reaction achieved the best results for NOM degradation. However, in the case of trihalomethane formation potential (THMFP), ozonation at a dose of 10 mg/L outperformed UV-LEDs AOPs (1000mJ/cm2 UV with 10mg/L H2O2 or Cl2), however this conclusion needs to be confirmed by additional bench and pilot-scale studies. In summary, UV-LEDs AOPs show great potential and value for future applications in drinking water however their impact on DBPFP should be further characterized.