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:4/6/2017)... Forecasts by Product Type (EAC), Biometrics, Card-Based ... & Logistics, Government & Public Sector, Utilities / Energy ... Nuclear Power), Industrial, Retail, Business Organisation (BFSI), Hospitality & ... for a definitive report on the $27.9bn Access Control ... ...
(Date:4/5/2017)... , April 4, 2017 KEY FINDINGS ... to expand at a CAGR of 25.76% during the ... is the primary factor for the growth of the ... https://www.reportbuyer.com/product/4807905/ MARKET INSIGHTS The global stem ... technology, application, and geography. The stem cell market of ...
(Date:3/30/2017)... ANGELES , March 30, 2017  On April ... Hack the Genome hackathon at Microsoft,s ... exciting two-day competition will focus on developing health and ... Hack the Genome is the ... been tremendous. The world,s largest companies in the genomics, ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... ... announced today that they have entered into a multiyear collaboration to identify and ... researchers with additional tools for gene editing across all applications. , Under the ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... genomics analysis platform specifically designed for life science researchers to analyze and ... researcher Rosalind Franklin, who made a major contribution to the discovery of ...
(Date:10/11/2017)... ... 2017 , ... ComplianceOnline’s Medical Device Summit is back for its 4th year. ... San Francisco, CA. The Summit brings together current and former FDA office bearers, regulators, ... government officials from around the world to address key issues in device compliance, quality ...
(Date:10/11/2017)... ... October 11, 2017 , ... Disappearing forests and increased emissions are the ... million people each year. Especially those living in larger cities are affected by air ... one of the most pollution-affected countries globally - decided to take action. , “I ...
Breaking Biology Technology: