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Water Quality Assessment of AC Condensate for Onsite Collection and Use
Citation:
Jahne, M., D. King, K. Kovalcik, M. Donohue, S. Pfaller, K. Helmick, G. Eades, M. Pait, M. Nye, S. Thimons, AND J. Garland. Water Quality Assessment of AC Condensate for Onsite Collection and Use. 2023 WateReuse Symposium, Atlanta, GA, March 05 - 08, 2023.
Impact/Purpose:
Air conditioning condensate can provide a significant source of water for building-scale collection and use, yet its quality has been poorly characterized to support risk-based management practices. This poster will present an analysis of opportunistic pathogens and metal ions in condensate collections to inform the development of fit-for-purpose onsite reuse guidance. Participants will: Recognize the potential for AC condensate collection and use in large buildings Understand the relevant water quality concerns for fit-for-purpose condensate reuse Learn how the growth of Legionella and other opportunistic pathogens can be controlled in condensate collection systems
Description:
Onsite collection of air conditioning (AC) condensate can provide significant quantities of water for non-potable applications such as cooling towers and landscape irrigation. While generally considered a high-quality source, empirical studies of condensate water quality to inform appropriate risk management practices have been limited. Potential concerns include opportunistic pathogens such as Legionella that can colonize premise plumbing systems and metals that may be leached from component materials by high-purity condensate water. This study characterized the quality of AC condensate from 13 air handling units across 4 geographic locations, focusing on contaminants specifically relevant for fit-for-purpose use in cooling towers or irrigation. High heterotrophic plate counts (103 – 104 CFU/mL) indicate microbial instability of the untreated water and the potential to support bacterial growth. Moreover, low-level detections of cultivable Legionella and of L. pneumophila serogroup 1, Mycobacterium avium, and M. intracellulare by qPCR directly demonstrate the occurrence of opportunistic pathogens in these systems. Metal concentrations were generally low, yet lead and copper were elevated in samples from one site known to possess older plumbing materials. These results support the need for appropriate condensate management practices, such as disinfection and corrosion control, when collecting for onsite reuse. Results will be used to inform the development of risk-based guidelines for these systems, facilitating the incorporation of condensate collection and use within relevant plumbing codes and reuse policies.