Disinfection by-product formation during UV/Chlorine treatment of pesticides in a novel UV-LED reactor at 285 nm and the mitigation impact of GAC treatment

Abstract

The UV/Chlorine process has gained attention in recent years due to the high quantum yield and absorbance of the chlorine species. However, there are still many unknowns around its application as a treatment for drinking water. The potential for the formation of disinfection by-products (DBPs) is one of them.There are no studies reporting on the formation of Trihalomethanes (THMs) or Haloacetic Acids (HAAs) in complex matrices, such as real source waters, at UV wavelengths tailored to the UV/Chlorine process, which has been possible thanks to the development of Light Emitting Diodes (LEDs). In addition, consideration of mitigation measures that might be needed after UV/chlorine treatment for full scale application have not been previously reported. Specifically, the novelty of this work resides in the use of an innovative reactor using UV-LEDs emitting at 285 nm for the removal of three pesticides (metaldehyde, carbetamide and mecoprop), the evaluation of THM, HAA and bromate formation in real water

Stability of Polymeric Membranes to UV Exposure before and after Coating with TiO2 Nanoparticles

“…The appearance of different colored zones could be related to the collimated beam tests made under UV light above the surface of the reactor ( Figure S4, Supplementary Data ). Despite assuming that the light beams are parallel to each other and perpendicular to the irradiated surface, the complexity of the UV distribution in the reactor leads to non-uniform irradiation due to the reflectance on its surfaces [ 36 ].…”

Performance of Cooking Aerosol Treatment in China Catering: a Review and Assessment

“…In practice, it was divided into UV device and Photocatalytic oxidation (PCO) device, which the latter had higher efficiency to generate "active oxygen" by aid of catalyst. This method could not only purify organic particles, but also disinfect and sterilize [35]. However, it should avoid droplets or large-size particles (including PM, oil, grease, etc) damaging UV lamp, so it always installed guide plate or other purifying unit before UV and photo-catalytic oxidation unit in China.…”

Assessment of 265-nm UV-LED for direct photolysis and advanced oxidation of N-nitrosamines and 1,4-dioxane

“…In addition, UV-LEDs emitting at shorter wavelengths could enhance the formation of hydroxyl radicals from H2O2 or NH2Cl, which in turn would help degrade 1,4-dioxane. Another method of improving the UV-LED AOP is by using hypochlorite ions instead of H2O2 or NH2Cl along with the 285nm emitting UV-LED (Carra et al, 2020;Gao et al, 2020). However, N-nitrosamine photolysis would be very limited at 285 nm.…”