Ultraviolet (UV) rays offer strong germicidal properties that can disinfect water. This method has long been in common use in the cosmetic, pharmaceutical, beverage and electronics industries. For municipal water, ultraviolet water disinfection has largely been replaced with chlorination, but it remains an effective means of water treatment. Here is an overview on UV water disinfection in Pisgah Forest, NC and how it works.
What is UV water disinfection?
UV water disinfection is the process of exposing water to UV radiation. There are three wavelength zones: UV-A, UV-B and UV-C. The last one, UV-C, offers the germicidal properties needed for water decontamination.
This was the method used to treat water in the early 1900s. Later, due to high operating costs, chlorine became the preferred method for water treatment. There are few UV water treatment plants in the U.S., but over 2,000 in Europe. Disinfectant systems are divided as Class A or Class B units.
In a Class A unit, the treatment has an intensity and saturation rating of at least 40,000 uWsec/cm2. It is designed for initial water treatment, as in a municipal plant. These systems disinfect and remove dangerous microorganisms, including viruses and bacteria. Once treated, the water is accessible for public use. The method is not designed to convert wastewater to drinking water or treat obviously contaminated water.
A Class B unit allows for additional treatment to water already rendered safe. These are usually home-based and designed to remove “nuisance” bacteria. If water contains a dangerous pathogen, like E. coli, this unit will not neutralize it.
How does it work?
Systems work by exposing water to UV-C radiation, which contains germicidal properties. Radiation emanates from lamps that operate within the range of 254 manometers. The treatment does not remove organisms, but it neutralizes them by changing their DNA. This renders them unable to reproduce or cause contamination.
Exposure time is measured in microwatt seconds per square centimeter, or uWsec/cm2. The minimum exposure required by the U.S. Department of Health and Human Services is 16,000 uWsec/cm2. Most manufacturers create exposure at 30,000 to 50,000 uWsec/cm2, and most bacteria are destroyed at 7,000 uWsec/cm2. While it sounds like overkill, the constant demand on these systems makes this intensity level vital.
Lamps’ intensity decreases with use, making timely replacement critical. Many systems include a warning device so new lamps can be installed on time.
By itself, UV radiation does not affect the taste or smell of water—that arises from the minerals in water that are unique to the environment. There are organisms that can survive UV-C radiation if it is not set at a high intensity. Basically, while this form of water treatment works well, it must be used correctly to ensure safe, potable water.
Royal Water Works, Inc. offers water testing in Pisgah Forest, NC. If you are concerned about the efficiency of your ultraviolet water disinfection or any other system, we can check and see if your water contains bacteria. Call us today to schedule a visit or learn more about our services.
Categorised in: UV Water Disinfection