Ultraviolet (UV) sanitizing units are used in many water purification systems to control bacteria and have certain applications for ozone deustruction, chlorine destruction, and TOC reduction. UV units can be effective water treatment tools, but it is important to recognize what UV can do as well as the strength of the UV which is commonly known as UV Dose. UV Dose needed for each application is different. For example, for ozone residuals of 1.0 ppm destruction, a dosage of 90 mJ/cm2 is reccommended while for disinfection purpose, dosage 30 mJ/cm2 is commonly used as a industrial standard.UV is most commonly used for microorganism disinfection by disrupting DNA so they are no longer able to maintain metabolism or reproduce. The degree of inactivation by ultraviolet radiation is directly related to the UV dose applied to the water. The dosage, a product of UV light intensity and exposure time, is measured in microwatt second per square centimeter (µws/cm2 ). Most UV units are designed to provide a dosage greater than 30,000 µws/cm2 or 30 mJ/cm2 after one year of continuous operation to destroy 99.9% of the microorganism present in the influent water stream. Notice that UV does not effectively disinfect some organisms (most molds, protozoa, and cysts of Giardia lamblia and Cryptosporidium) since they require a higher dose.
The UV unit mostly designed to give specific dosage for specific water flow rate. Therefore, if the unit is said to deliver dosage 30 mJ/cm2 for flow rate 24 m3/hour, means it will deliver lower dosage if your water flows faster than 24 m3/hour or the opposite higher dosage if your water flows lower than the mentioned flow rate. The low dosage resulting in wrong UV application will result in insufficient dose and could result in disinfection failure that results in low microbial quality of the final water. Therefore, to ensure proper dose and application, don’t hesitate to contact TriotirtaCare as authorized Aquafine distributor for Indonesia.