Understanding UV Disinfection Systems

December 21, 2021

Treating wastewater is a multi-step process, ranging from filtering out solids to disinfecting the water to get rid of harmful pathogens. Even the groundwater supply is likely to contain bacteria and viruses that can sicken you if you drink the untreated water. While some facilities use chlorine to kill germs, UV radiation is a safe, effective and overall better way to kill germs, bacteria and other harmful elements. UV disinfection systems are now commonly used to treat wastewater.

Over time, state and federal regulations have lowered the amount of “safe” E. coli output in wastewater. Wastewater treatment facilities either have to use more chlorine, which is not necessarily the best chemical for drinking water, or find an alternative solution. UV disinfection can be quite efficient, and does not affect drinking water in a negative way.

What is a UV disinfection system?

UV disinfection systems rely on ultraviolet light to kill pathogens. UV light is not visible, but it is powerful: by exposing the wastewater to a wavelength between 250 and 270 nm, it can “inactivate” organisms like bacteria and viruses. The light intensity, dose time and reactor quality all affect how long it takes to disinfect the water, as does the original quality of the water.

If the water quality is suitable for UV disinfection, it will be exposed to several mercury arc lamps or amalgam lamps within a reactor (usually a stainless steel or concrete vessel). The lamps use either low or medium pressure to expose the wastewater to UV radiation. After a prescribed amount of time, the pathogens are killed and the water is on its way to being usable for cooking, drinking, bathing and more.

When using UV disinfection systems, it’s crucial to make sure that the level of total suspended solids is within the recommended range. The more solids there are in the water, the more they will absorb the radiation, allowing some pathogens to escape unscathed. Dissolved salts and other minerals can have the same effect. When designing your system, keep the pre-UV treatment process in mind, as it will affect the length and intensity of the UV dose.

Benefits of UV disinfection

UV disinfection systems offer a number of benefits, including:

  • No harsh chemicals: UV radiation is a safe and effective way of killing all microorganisms, without using harsh chemicals like chlorine.
  • Environmentally friendly: Since there are no chemicals involved in the disinfection process, the wastewater treatment process won’t form any toxic chemical byproducts.
  • Cost-effective: UV disinfection is one of the cheapest and easiest ways to treat wastewater, so your facility will save money over the long term.
  • Easy to maintain: The biggest maintenance task you’ll perform is periodically cleaning the UV lamps, which can develop mineral scale. Mineral scale blocks the light from doing its job, but it’s easy to get rid of during regular maintenance.

In short, UV disinfection systems are a safe and easy way to treat your wastewater. To learn more about available system components and design, call Enviro-Line Co., Inc. today.

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