If you are the owner of a home swimming pool or hot tub, it is important to understand the potential risks of Legionella and Legionnaires' disease. Legionella is a type of bacteria that can cause Legionnaires' disease. The name "Legionella" originates from a "mystery illness" outbreak in July 1976 in Philadelphia, which sickened 221 people, mostly U.S. veterans, leading to it being called Legionnaires' disease. The extensive media coverage of Legionnaires' disease created a certain level of panic. On January 18, 1977, the causative agent of the disease was identified as a previously unknown bacterium, subsequently named Legionella. This disease is a severe form of pneumonia that spreads through inhaling water droplets or mist containing the bacteria. Legionella is commonly found in natural water bodies (such as rivers and lakes), but it proliferates more easily in certain man-made environments (such as cooling towers, water parks, hot water systems, fountains, and home pools).
Characteristics and Transmission of Legionella
Characteristics:
- Bacteria Types: The Legionella genus includes various bacteria, with the most common and dangerous being Legionella pneumophila.
- Growth Environment: Warm water environments (25-45°C) are particularly conducive to the growth and reproduction of Legionella. The presence of organic matter, iron, and other nutrients in the water also facilitates their proliferation.
Transmission:
- Inhalation: Water droplets or mist containing Legionella can be inhaled through the respiratory tract.
- Risk Environments: The primary risk environments include cooling towers of air conditioning systems, hot water systems, humidifiers, fountains, and other devices that may generate water mist.
Since its discovery in the late 1970s, Legionnaires' disease has been an ongoing challenge in hotels, dormitories, cruise ships and other large shared living spaces.
After decades of dedicated research, scientists and engineers have discovered not only the cause and cure for this dangerous disease, but also preventative measures that can help stop the spread. Also explored are how the disease was discovered and the challenges faced in inhibiting growth and avoiding infection.
Protecting Household Hot Water Systems and Artificial Water Circulation Systems from Legionella Infection
Methods for prevention and control include both localized and systemic disinfection. Systemic disinfection can be achieved through various methods. Copper-silver ionization and chlorination are the most popular methods, but both have drawbacks. For effective ionization, the water's pH must be kept below 8.5 to prevent copper-silver ions from interfering with disinfection practices. To make this method effective, copper-silver ions must be continuously added to the water system. There are systems that can automatically test and dose the ions, but these can pose a cost barrier in some cases. Chlorine is also affected by the water's pH, and its efficacy is limited as it requires a long contact time to significantly reduce bacterial growth.
However, the industry is increasingly leaning towards using filtration methods, specifically UV irradiation, as an intervention.
UV Water Disinfection Systems and How They Eliminate Legionella
UV water disinfection systems can effectively eliminate Legionella. UV disinfection technology works by emitting ultraviolet light at a specific wavelength (usually 254 nm) that disrupts the DNA and RNA of microorganisms, preventing them from reproducing and surviving. This method is effective against various microorganisms, including bacteria, viruses, and protozoa.
How UV Water Disinfection Systems Eliminate Legionella:
- DNA/RNA Disruption: UV irradiation directly disrupts the DNA and RNA structures of Legionella, rendering them unable to reproduce and cause infection.
- No Chemical Residue: Unlike chemical disinfection methods, UV disinfection does not introduce any chemicals into the water and does not leave any residues, making it a physical method of disinfection.
- Immediate Effect: UV disinfection works instantaneously; microorganisms are inactivated as the water flows through the UV lamp chamber.
Our UV sterilizers destroy harmful viruses, bacteria and other microorganisms that would normally contaminate recreational water. Contact us today to learn more about how we can help protect you and your family from Legionella and other harmful, unwanted bacteria.
