Cincinnati Opens $30 Million UV Water Treatment Plant
By Sara Jerome
Cincinnati's water may get a little bit cleaner.
The city's water utility, 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."
And 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 AP, 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 (IUA). Myths include that "adding a UV system does not make financial sense unless required."
The EPA says 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."
For more on disinfection decision-making, check out Water Online’s coverage of a utility that decided to wait on the UV approach because it said it was not "mature" enough yet.
Image credit: "Cincinnati Water Works," © 2008 haglundc, used under an Attribution-NonCommercial 2.0 Generic license: http://creativecommons.org/licenses/by-nc/2.0/