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Microbial Risk Management for Atmospheric Condensate Collections
Citation:
Jahne, M., S. Pfaller, D. King, M. Donohue, N. Brinkman, S. Keely, B. Davis, AND J. Garland. Microbial Risk Management for Atmospheric Condensate Collections. Presented at First International Atmospheric Water Harvesting Summit, Tempe, AZ, February 08 - 09, 2024.
Impact/Purpose:
Atmospheric water harvesting can provide a high-quality water source for potable or non-potable applications. However, like other water sources, collected condensate must be managed appropriately to prevent microbial growth. Of particular concern are opportunistic pathogens such as Legionella and Mycobacterium spp. that are known to proliferate in building water systems. In this study, we demonstrate the bacterial contamination of real-world condensate collections from an atmospheric water harvesting unit and commercial-scale air conditioning systems. Heterotrophic plate counts ranging 101-104 per mL in both condensate types indicate the ability of these relatively clean cold-water sources to support microbial growth. 16S sequencing shows a diverse microbial community including pathogen-containing genera such as Legionella and Pseudomonas spp. Moreover, culture-based and molecular detections of opportunistic pathogens L. pneumophila, L. pneumophila serogroup 1, M. avium, and M. intracellulare in various air conditioning condensate collections provide direct evidence of their potential to grow in these systems. Our results highlight the need for disinfection and downstream water quality management in atmospheric condensate uses where human exposure is possible.
Description:
Atmospheric water harvesting can provide a high-quality water source for potable or non-potable applications. However, like other water sources, collected condensate must be managed appropriately to prevent microbial growth. Of particular concern are opportunistic pathogens such as Legionella and Mycobacterium spp. that are known to proliferate in building water systems. In this study, we demonstrate the bacterial contamination of real-world condensate collections from an atmospheric water harvesting unit and commercial-scale air conditioning systems. Heterotrophic plate counts ranging 101-104 per mL in both condensate types indicate the ability of these relatively clean cold-water sources to support microbial growth. 16S sequencing shows a diverse microbial community including pathogen-containing genera such as Legionella and Pseudomonas spp. Moreover, culture-based and molecular detections of opportunistic pathogens L. pneumophila, L. pneumophila serogroup 1, M. avium, and M. intracellulare in various air conditioning condensate collections provide direct evidence of their potential to grow in these systems. Our results highlight the need for disinfection and downstream water quality management in atmospheric condensate uses where human exposure is possible.