Science Inventory

Electrically heatable carbon nanotube point-of-use filters for effective separation and in-situ inactivation of Legionella pneumophila

Citation:

Oh, Y., R. Noga, V. Shanov, H. Ryu, H. Chandra, B. Yadav, J. Yadav, AND S. Chae. Electrically heatable carbon nanotube point-of-use filters for effective separation and in-situ inactivation of Legionella pneumophila. Chemical Engineering Journal. Elsevier BV, AMSTERDAM, Netherlands, 366:21-26, (2019). https://doi.org/10.1016/j.cej.2019.02.054

Impact/Purpose:

Legionella species are ubiquitous in both natural and engineered water systems. Legionella can colonize water distribution lines and building plumbing, contaminating water supplies after it has been centrally treated. Legionella infection is caused by the inhalation of water aerosols, and most cases of disease are linked back to manmade systems such as cooling towers, potable water systems, evaporative condensers, whirlpool spas, humidifiers, air washers, and decorative fountains. Six treatment technologies (e.g., three chlorine and three non-chlorine based methods) for effective control of Legionella in premise plumbing systems have been recognized by EPA. However, the effectiveness of each of these methods can vary, and some of them have negative effects associated with their use, including formation of disinfection byproducts, negative aesthetic effects on water and adverse health effects, and corrosion of plumbing systems. One alternative approach could be to implement “barrier protection” at the point-of-use (POU). Numerous studies have investigated the efficacy of POU filters installed in high-risk areas to prevent the transmission of waterborne pathogens to their immunocompromised hosts. The POU membrane filtration can limit exposure to pathogens; however, their short maximum lifetime (1 or 2 weeks of continuous use) and membrane clogging (or fouling) have limited their use. Therefore, it is desirable to develop new approaches of membrane cleaning for long-term use of the POU filters. In this study, we developed a novel electrically heatable carbon interfaces on commercially available membranes for simultaneous separation and inactivation of Legionella from health care and public water systems.

Description:

Opportunistic waterborne pathogens (e.g., Legionella spp.) may persist in water distribution systems despite municipal chlorination and secondary disinfection and can cause health care-acquired infections. This warrants development of novel pathogen removal and/or inactivation systems. In this study, electrically heatable carbon nanotube composite membranes have been designed to separate and inactivate Legionella pneumophila in water. The composite membranes completely removed Legionella and were also able to inactive them at 100% efficiency using ohmic heating (20 V, 60 seconds). The novel membranes could be used as a final barrier to provide complete rejection of particles and pathogens and also to simultaneously eliminate microorganisms in private and public water supplies.