Synergistic Disinfection of Drinking Water Using Ultraviolet and Ozone Co-Generated from the Same UV Lamp

摘要

A low pressure ultraviolet (UV) lamp with a high-purity quartz envelop emits two principal wavelengths: 254 nm (efficiency about 33%) and 185 nm (efficiency 3%). The 185 nm UV light is absorbed by oxygen in the air to generate ozone. The ozone generated in the annular space between the UV lamp and the quartz sleeve can then be injected into drinking water passing through a UV reactor on the other side of the quartz sleeve. The 254 nm UV light passes directly through the quartz sleeve into the drinking water passing through the outer annular space. This UV light is very effective in the disinfection of bacteria, protozoa and most viruses, with the exception of adenovirus, which ahs proven to be very insensitive to UV treatment. However, adenovirus is very sensitive to ozone disinfection. Thus the combination of UV (254 nm) and ozone (generated from the 185 nm UV) provides a synergistic disinfection treatment that handles all known pathogens. We have developed a model to allow us to calculate the concentration of ozone in the gas exiting the inner annular space. The model is based on the known absorption properties of O2 at 185 nm, the partial pressure of O2 in the gas flowing through the inner annular space and the known quantum yield for generation of O3. Comparisons of the ozone concentrations calculated from this model with experimental measurements show excellent agreement.