Navigation Links
Pitt study finds 'green' water treatments may not kill bacteria in large building cooling systems
Date:12/10/2010

PITTSBURGH Nonchemical treatment systems are touted as environmentally conscious stand-ins for such chemicals as chlorine when it comes to cleaning the water-based air-conditioning systems found in many large buildings. But a recent study by University of Pittsburgh researchers suggests that this diverse class of water-treatment devices may be ineffective and can allow dangerous bacteria to flourish in the cooling systems of hospitals, commercial offices, and other water-cooled buildings almost as much as they do in untreated water.

The two-year study by a team in Pitt's Swanson School of Engineering is the first to thoroughly investigate the ability of nonchemical treatment devices (NCDs) to control the growth of bacteria in water-based cooling systems. Of the five NCDs tested, none significantly prevented bacterial growth. On the other hand, the researchers found that standard chlorine treatment controlled these organisms, even after bacteria had been allowed to proliferate.

"Our results suggest that equipment operators, building owners, and engineers should monitor systems that rely on NCDs to control microorganisms," said coinvestigator Janet Stout, a research associate in the Swanson School's Department of Civil and Environmental Engineering and director of the Pittsburgh-based Special Pathogens Laboratory. Stout worked with fellow lead investigator Radisav Vidic, chair and William Kepler Whiteford Professor of civil and environmental engineering, and Pitt civil engineering graduate student Scott Duda.

"These cooling systems are energy efficient and, if properly treated, very safe," Stout continued. "But based on our results, nonchemical devices alone may not be enough to control microbial growth. One possible measure is to add chemical treatment as needed to prevent a potential health hazard."

The air systems the team investigated work by piping chilled water throughout a building. The water warms as it exchanges temperature with the surrounding air and becomes a hotbed of microorganisms before returning to a central cooling tower to be cleaned and re-chilled. If the returning water is not thoroughly cleaned, bacteria can spread throughout the system, exposing people within the building to possible infection and hampering the system's energy efficiency.

The team constructed two scale models of typical cooling towers. One model remained untreated while the other was treated with five commercially available NCDs installed according to the manufacturers' guidelines. Each device was tested for four weeks. Chlorine was administered three times during the study to demonstrate that an industry-accepted chemical treatment could kill bacteria even in a heavily contaminated system.

The five devices tested represent different classes of NCDs, Vidic said. Pulsed electric-field devices emit electromagnetic energy that, in theory, ruptures bacterial membranes and activates particles that ensnare the bacterium. Electrostatic devices function similarly by producing a constant static field.

Ultrasonic devices pass a mixture of untreated water and high-pressure air through a chamber that purportedly disintegrates the bacterium with sound waves. For hydrodynamic cavitation devices, two cone-shaped water streams collide to form a vacuum region filled with high-friction bubbles that collide with and presumably deactivate the bacteria. Finally, the team tested a magnetic device, although magnetic NCDs are intended to prevent mineral buildup, not control bacterial growth.


'/>"/>

Contact: Morgan Kelly
mekelly@pitt.edu
412-624-4356
University of Pittsburgh
Source:Eurekalert  

Related biology news :

1. Phase III study compared neoadjuvant therapy with lapatinib or trastuzumab for early breast cancer
2. Scientists begin 5-month study of cloud life cycles
3. Study: mechanism that controls cell movement linked to tumors becoming more aggressive
4. New UCLA study raises questions about genetic testing of newborns
5. Illinois study: Ginseng just got better -- not as bitter
6. Study of how genes activate yields surprising discovery
7. Northern wildfires threaten runaway climate change, study reveals
8. Study reveals new possibility of reversing damage caused by MS
9. Electronic cigarettes are unsafe and pose health risks, UC Riverside study finds
10. Africa can feed itself in a generation: Study
11. New study calls for greater awareness of food supply for children with diabetes
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Pitt study finds 'green' water treatments may not kill bacteria in large building cooling systems
(Date:6/22/2016)... American College of Medical Genetics and Genomics was once again ... of the fastest-growing trade shows during the Fastest 50 Awards ... Las Vegas . Winners are ... of the following categories: net square feet of paid exhibit ... 2015 ACMG Annual Meeting was ranked 23 out of 50 ...
(Date:6/20/2016)... 20, 2016 Securus Technologies, a leading ... for public safety, investigation, corrections and monitoring announced ... it has secured the final acceptance by all ... Managed Access Systems (MAS) installed. Furthermore, Securus will ... be installed by October, 2016. MAS distinguishes between ...
(Date:6/9/2016)... Finland , June 9, 2016 ... National Police deploy Teleste,s video security solution to ensure the ... France during the major tournament ... data communications systems and services, announced today that its video ... Prefecture to back up public safety across the ...
Breaking Biology News(10 mins):
(Date:12/2/2016)... ... 2016 , ... The Conference Forum has announced that the 3rd annual ... on February 1-3, 2017 at the Roosevelt Hotel in New York City. Led by ... unique 360-degree approach, which addresses the most up-to-date information regarding business aspects, clinical advancements ...
(Date:12/2/2016)... YORK , Dec. 1, 2016   SurePure, ... photopurification, announced today that the Company has concluded an ... the right for a 90-day period to acquire units ... value of approximately USD 3.7 million.  ... agreement with Tamarack under which Tamarack will seek regulatory ...
(Date:11/30/2016)... November 30, 2016 The global ... players hold a dominant share in the overall market. ... International, Inc., and Merck KGaA, held a lion,s share ... Market Research observes that these companies are expected to ... products that are do not require rabbit pyrogen testing ...
(Date:11/30/2016)... , Nov. 30, 2016  Tempus, a ... cancer care, and Penn,s Abramson Cancer Center have ... a positive response to immunotherapy treatment based on ... As part of a research collaboration, Tempus ... and melanoma cancer patient data to Penn. Utilizing ...
Breaking Biology Technology: