University of Pittsburgh Research Projects
NonChemical Treatment Devices
The NonChemical Treatment Device study was conducted by Dr. Stout, lead investigator Radisav Vidic, chair and William Kepler Whiteford Professor of civil and environmental engineering, and then-Pitt civil engineering graduate student Scott Duda. The specific objective of this investigation was to provide a controlled, independent, and scientific evaluation of several classes of non-chemical treatment devices (NCDs) for controlling biological activity in a model cooling tower system. The two-year study was funded by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).
Microbial growth in cooling water systems causes corrosion, decreases energy efficiency, and has the potential to cause human infection. Control of microbial growth in these systems is typically achieved with the use of chemical biocides. Recently, non-chemical water treatmentmethods have seen increased use as an alternative. However, few objective studies with an untreated system as a reference are available to verify the efficacy of these devices to control microbial growth in cooling towers.
Five NCDs were evaluated for efficacy in reducing planktonic (bulk water) and sessile
(biofilm) microbial populations within a pilot-scale cooling system. The devices included
magnetic, pulsed electric field, electrostatic, ultrasonic, and hydrodynamic cavitation:
- Magnetic Device (MD): RT-750-K Superior Water Conditioner®, Magnatech Corp, Forth Wayne, Ind.
- Puslsed Electric Field Device (PEFD): Dolphin Series 3000, Clearwater Systems Corp., Essex, CT
- Electrostatic Device (ED): FluidTron®, ElectroStatic Technologies, Inc., Kansas City, Kan.
- Ultrasonic Device (UD): Sonoxide® B02, Ashland Water Technologies, Wilmington, Del.
- Hyrodynamic Cavitation Device (HCD): VRTX-10, VRTX Technologies, Schertx, Tex.
> Read the study
Biological Control in Cooling Water Systems Using Non-Chemical Treatment Devices, ASHRAE 1361RP (PDF)
> Read the paper
The first study of the efficacy of nonchemical treatment devices for controlling microbiological activity (planktonic and sessile) within a pilot scale model cooling tower. Funded by ASHRAE.
Biological control in cooling water systems using nonchemical treatment devices HVAC&R Research Scott Duda, Janet E.. Stout & Radisav Vidic (2011) HVAC&R Research, 17:5, 872-89. (Request reprint)
> Listen to podcast
HVAC 360 Nonchemical Water Treatment Devices
Dr. Janet E. Stout gives in-depth interview to Matt Nelson of HVAC 360
Janet E. Stout, PhD
Janet E. Stout, PhD is the author of the Legionella "Agent Summary" in the 5th Edition of the CDC's Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition
U.S. Department of Health and Human Services Centers for Disease Control and Prevention and National Institutes of Health Fifth Edition, Feb 2007.
Victor L Yu MD
Legionella Infection. Harrison's Principles of Internal Medicine, 17th ed, McGraw-Hill, 2008
Legionella species. www.antimicrobe.org 2008.
Legionella species. Antimicrobial Therapy and Vaccines, ESun Technologies, 2002.
Janet E Stout, PhD, and Victor L Yu MD
Legionella Infection. Epidemiology, Clinical Manifestations, and Therapy. UpToDate, 2008.
Nosocomial Legionella Infection. Hospital Epidemiology and Infection Control, 3rd ed. Lippincott WW, 2004
Control of Legionella Infection. Disinfection, Sterilzation, and Preservation, 5th ed, Lippincott WW, 2001
Sue M. Mietzner, MS; Janet E Stout PhD
Legionella. Infectious Diseases, 3rd ed, Lippincott WW, 2004
Janet E Stout, PhD; John D. Rihs, BS; Victor L Yu MD
Legionella. Manual of Clinical Microbiology, 8th ed, American Society of Microbiology.
Cianciotto N, Abu Kwaik Y, Edelstein PH, Fields BS, Geary DF, Harrison, TH, Joseph CA, Ratcliff, Stout JE, Swanson MS. Legionella. State of the Art 30 years after Its recognition. American Society of Microbiology, 2006.
Please visit our educational website www.legionella.org for the most current scientific references on Legionnaires' disease. Selected by "Clinical Infectious Diseases," the office journal of the Infectious Disease Society of America (IDSA), for scientific content and adherence to Internet standards, legionella.org is the most comprehensive online resource for Legionella. Articles are in PDF format.