Largest UV Disinfection Treatment Plant Opens in North America

The Greater Cincinnati Water Works added a new layer to its drinking water treatment process this month by opening an ultraviolet disinfection plant.

“Water will reach the treatment plant’s ultraviolet reactors and bulbs after going through the processes of sand filtration and granular activated carbon absorption,” The Associated Press reported.

The $30 million treatment plant makes this utility “the largest in North America to use UV disinfection along with sand filtration and carbon absorption,” Gannett’s Cincinnati Ohio News reported. The upside of UV disinfection is that it cleans water without adding chemicals, odors, or taste to the water supply, nor does it remove beneficial chemicals.

Gannett provided a short description of the technology: “Ultraviolet (UV) rays are energy-rich electromagnetic rays found in the natural spectrum of sunlight. They are in the range of the invisible shortwave light, having a wavelength ranging from 100 to 400 nanometers. How small is a nanometer? By comparison, the diameter of a human hair is 50,000 to 100,000 nanometers.”

Here’s how it works: “When the ultraviolet energy hits the reproductive mechanisms of bacteria and viruses, the genetic material (both DNA and RNA) is rearranged. The result: the pathogens can no longer reproduce and effectively are dead.”

According to the Associated Press, the new plant will help Cincinnati comply with EPA standards for drinking water.

UV disinfection, as a water treatment process, still faces a lot of misconceptions, according to the International Ultraviolet Association. Myths include that “adding a UV system does not make financial sense unless required.”

According to the EPA, UV disinfection is not as cost-effective as chlorination, “but costs are competitive when dechlorination is used and fire codes are met.” On the positive side, UV disinfection is user-friendly and space efficient, it said. Some related regulatory advice from the EPA is that “any UV disinfection system should be pilot tested prior to full-scale operation to ensure that it will meet discharge permit requirements for a particular site.”