Ultraviolet Advanced Oxidation

One step being considered for the Water2WATER treatment process involves the use of high intensity ultraviolet (UV) light in combination with a strong oxidising agent such as ozone or hydrogen peroxide. The process is designed to destroy any residual trace organic compounds in the water following reverse osmosis as well as providing an additional barrier for disease-causing micro-organisms (pathogens). This process is typically the final stage of treatment and involves dosing the water with oxidising agent and passing it through a number of chambers, in which there are high-intensity UV lamps, mounted in quartz tubes.

The UV light triggers or catalyses the formation of hydroxyl radicals from the oxidising agent, which then achieves chemical oxidation of organic contaminants in water. The UV light on its own is capable of breaking chemical bonds in the DNA or RNA of any pathogens, which prevents them from replicating and causing infection, a process which is commonly used in drinking water treatment.

Figure 1: Advanced oxidation – UV/peroxide facility - PWN Water Supply, Andijyk, North Holland
(treats water from Lake Ijssel, end of Rhine River)

UV intensity monitoring equipment on each of the UV reactors automatically adjusts the UV intensity if necessary, and shuts the system down and raises an alarm if the intensity falls below set limits.