CEE Seminar: Saprozoic Pathogens in Water - An Emerging Environmental Engineering Problem

McDonnell Douglas Engineering Auditorium
Charles Haas, Ph.D.

LD Betz Professor and Department Head
Department of Civil, Architectural and Environmental Engineering
Drexel University

Abstract: Over the past several decades, it has been realized that in engineered water systems, such as water distribution systems, building plumbing, water storage tanks and constructed water features, a diverse ecosystem can emerge that can be conducive for the growth of pathogens. These organisms, termed saprozoic by Ashbolt, include Mycobacterium, Legionella and others. Many exposures to these organisms arise via inhalation of aerosols generated from these waters. This problem therefore requires many of the elements of environmental engineering and science for its solution, including:

  • Growth kinetics, including multipopulation dynamics​
  • Heat and mass transfer
  • Classical and molecular biology
  • Chemical interactions (corrosion, disinfection)
  • Process modeling
  • Water-air transfer processes
  • Air dispersion in the indoor and outdoor environments
  • Building ventilation characteristics
  • Risk assessment

I will present the overview of a problem, cases studies on applying risk assessment to the problem, and current and forefront research needs.

Bio: Charles N. Haas, Ph.D. is the LD Betz Professor of Environmental Engineering and head of the Department of Civil, Architectural and Environmental Engineering at Drexel University, where he has been since 1991. He received his bachelor's degree in biology and master's degree in environmental engineering from the Illinois Institute of Technology and his doctorate in environmental engineering from the University of Illinois at Urbana-Champaign. He has served on the faculties of Rensselaer Polytechnic Institute and the Illinois Institute of Technology prior to joining Drexel. Haas co-directed the USEPA/DHS University Cooperative Center of Excellence – Center for Advancing Microbial Risk Assessment (CAMRA). He is a fellow of the International Water Association, American Academy for the Advancement of Science, the Society for Risk Analysis, the American Society of Civil Engineers, the American Academy of Microbiology and the Association of Environmental Engineering and Science Professors. He is a board-certified environmental engineering member by eminence of the American Academy of Environmental Engineers. He has received the Dr. John Leal Award and the AP Black Award of the American Water Works Association and the Clarke Water Prize. Over his career, Haas has specialized in the assessment of risk from and control of human exposure to pathogenic microorganisms, and in particular the treatment of water and wastewater to minimize microbial risk to human health. Haas has served on numerous panels of the National Research Council. He is a past member of the Water Science and Technology Board of the National Academies, and the U.S. EPA Board of Scientific Counselors.