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Legionellosis and recent advances in technologies for Legionella control in premise plumbing systems: A review
Citation:
Carlson, K., L. Boczek, S. Chae, AND H. Ryu. Legionellosis and recent advances in technologies for Legionella control in premise plumbing systems: A review. WATER. MDPI, Basel, Switzerland, 12(3):676, (2020). https://doi.org/10.3390/w12030676
Impact/Purpose:
Legionnaires’ disease and the waterborne pathogen associated with it have continued to garner the attention of the public, health professionals, and regulating bodies alike since its initial outbreak in 1976, demonstrated by the recent increase in public health guidance and policy. Legionnaires’ disease is a financial burden, with hospitalizations due to Legionella spp. costing nearly 434 million dollars annually in the U.S. While Legionella spp. can be found in both natural and artificial environments, most cases of disease are linked back to manmade systems. In particular, premise plumbing and the water systems associated with it – including cooling towers, whirlpools, mist machines, and decorative fountains – are the most common sources of infections. Because most cases of Legionnaires’ disease stem from premise plumbing, much research has gone into determining methods to inactivate or remove this pathogen in order to mitigate the risk. Currently, there are six technologies recognized by the U.S. Environmental Protection Agency (EPA) that can be used for control of Legionella: chlorine, chlorine dioxide, monochloramine, copper-silver ionization, ozone, and ultraviolet disinfection. However, the effectiveness of each of these methods can vary, and some of them have negative effects associated with their use. The three commonly used variations of chlorine each result in the formation of disinfection byproducts (DBPs) and can cause corrosion of plumbing. Copper-silver ionization can result in negative aesthetic effects on water and adverse health effects if high levels of either chemical are ingested. Ozone can also result in the formation of disinfection byproducts and does not result in a disinfectant residual. Ultraviolet (UV) disinfection does not provide an effect on water downstream of the unit and can result in mercury contamination if the lamp breaks; however, it does not result in any negative health effects or DBPs. Light emitting diodes (LEDs), a novel emerging technology, may be able to help overcome the shortcomings of the traditional lamps, as they do not contain mercury. LEDs are also more compact and durable than the mercury lamps, which may allow for them to be used at the point-of-use (POU). Further literature review on this emerging technology as well as six most commonly used treatment practices is presented in this review article.
Description:
This review discusses Legionella, among the most prolific and publicly well-known waterborne pathogens. The number of cases associated with Legionella continue to rise, as does its public awareness. Currently, cases associated with premise plumbing account for the largest number of legionellosis cases in the United States. So, while it is important to understand Legionella as such, it is also important to investigate how to treat drinking water in premise plumbing for Legionella and other waterborne pathogens. While there are currently several methods recognized as potential means of inactivating waterborne pathogens, a number of shortcomings continue to plague its implementation. These methods are generally of two types. First there are chemical treatments, such as chlorine, chlorine dioxide, monochloramine, ozone, and copper-silver ionization. Secondly there are physical treatments, such as thermal inactivation and filtration. Their shortcomings range from being labor-intensive and costly to having negative health effects if not properly operated. However, newly-developed technologies could better control waterborne pathogens by allowing for the simultaneous use of different treatment measures in plumbing systems. A novel technology which could prove effective is ultraviolet irradiation using light emitting diodes.
URLs/Downloads:
DOI: Legionellosis and recent advances in technologies for Legionella control in premise plumbing systems: A review
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