What types of microorganisms will UV sterilization inactivate?

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Ultraviolet Sterilization is unmatched in its efficiency, simplicity, and dependability when applied as a microorganism disinfectant. UV sterilization is a proven solution to waterborne planktonic algae as well as other harmful pathogen problems. Certain critical UV performance factors greatly affect all UV sterilizers, no matter who's the manufacturer.

Ultraviolet light is a spectrum of light just below the range visible to the human eye (below the blue spectrum of visible light in the chart above). UV light is divided into four distinct spectral areas-Vacuum UV (100 to 200 nanometers), UV-C (200 to 280 nanometers), UV-B (280 to 315 nanometers), and UV-A (315 to 400 nanometers). The UV-C spectrum (200 to 280 nanometers) is the most lethal range of wavelengths for microorganisms. This range, with 264 nanometers being the peak germicidal wavelength, is known as the Germicidal Spectrum.

It is critical to first identify the microorganism. Each type of microorganism requires a specific UV-C radiation exposure rate to successfully complete the disinfection process. The targeted microorganism must be directly exposed to the UV-C radiation long enough for the radiation to penetrate the microorganism's cell wall. However, it takes only seconds for UV-C light rays to inactivate waterborne microorganisms by breaking through the microorganism's cell wall and disrupting their DNA. This often totally destroys the organism, or at the very least will impair its ability to reproduce.

The size, biological makeup, and life cycle of a microorganism all play a critical part in successful germicidal disinfection. By way of comparison, there are approximately 65,000 known protozoa and only 4,500 bacteria of which all require their own specific UV-C dose. A microorganism’s size plays a significant role in the UV dose required to irradiate it. Protozoa is often many times larger than bacteria and therefore requires a much higher UV dose.

Life cycle is another critical factor that requires consideration when applying UV sterilization, the marine parasite cryptocaryon (saltwater white spot) is an excellent example of how complex a microorganism’s life cycle can be. Cryptocaryon has a four-part life cycle. A warm water parasite, cryptocaryon can be lethal to many species of marine fish. Regarding treatment; the aquaculture community has waged battles against cryptocaryon and has lost, specifically at the encysted (Tomont) stage simply due to its evasiveness by attaching itself to the substrate. Disease outbreaks still occur even with filtering the water column using extremely fast flow rates.

Prerequisites of achieving successful UV disinfection: Identify the “Target Microorganism”, consider its physical and life cycle characteristics, determine its required UV dose, determine the condition of the water to be treated (water temperature & UV Transmissibility). Contact a reputable UV manufacturer, ask questions regarding their equipment’s capacity, share your needs and then select the UV sterilizer model that best suits your application requirements.

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