From the water treatment industry’s perspective, the practice of controlling the proliferation of microbial fouling in HVAC/Industrial cooling water systems has traditionally been focused on keeping algae, slime and fungus in check. Without proper control, organisms will colonize, grow, and turn into biomass and biofilm. Displaced biomass can lead to restrictions in flow, loss of heat transfer and other serious water-borne problems. In addition, a longer-term challenge is that accumulated bacterial slimes (biofilm) will lead to microbiologically influenced corrosion, metal loss and system failure. Also, due to recent regulatory developments, the industry now has another objective to contend with. This is to reduce the potential formation of disease-bearing organisms such as Legionella Pneumophila. So, effective microbial control is at the center of overall cooling system performance as well the health of building occupants.
Cooling tower owners have numerous tools at their disposal. These tools include application of chemical biocides, cooling tower chemical disinfections, and the selective use of mechanical support methods. Among the mechanical support methods owners can rely upon we find deck covers (to shield sunlight), recirculating water filters (sand or media) to remove suspended solids continuously, basin cleaning filters to keep pans deposit free, and even air-intake screens to prevent additional dirt loading. Cooling water biocides are applied routinely and typically involve the use of two different product categories – oxidizing and non-oxidizing micro-biocides. These materials are designed to destroy existing organisms and also prevent new ones from growing. The strategy of using two separate chemical micro-biocides is to ensure that cellular destruction is complete, and that strains do not develop immunity to resist treatments.
Owners working with industry professionals have numerous monitoring tools at their disposal. Cooling tower inspections should be coupled with the use of microbiological testing. Micro testing is part of effective Water Management Plan development and includes testing for halogen reserves, bacteria and cellular activity, as well as specific testing for Legionella. Best practice might also incorporate the use of bio-film detection strategies. In conclusion, microbiological control of Industrial and HVAC cooling waters requires careful planning and resource allocation. An appropriate selection of the tools now available to building owners can be selected and implemented to prevent problems, preserve capital equipment, and ensure the health of building occupants.
“An outbreak of Legionnaires’ disease has sickened 11 people in Upper Manhattan, 10 of whom have been hospitalized, according to city health officials.
Eight people remained in the hospital on Thursday.
“This disease is very treatable with antibiotics,” Dr. Mary Bassett, the city’s health commissioner, said in a statement. “I encourage anyone with symptoms of Legionnaires’ disease to seek care early.”
The city’s Department of Health said it was “actively investigating” the cases, but had not yet determined the source of the bacteria. A spokesman for Mark Levine, a City Council member who represents the area and who was briefed on the outbreak, said inspectors took water samples from buildings between 145th and 155th Streets. While the city waits for the test results from the 20 cooling-tower systems that were sampled, it has already treated the towers’ water, said Dr. Demetre Daskalakis, the deputy commissioner of disease control.
The cluster of people infected all live in Upper Manhattan and are older than 50, health officials said.
Three of the 11 cases were identified on Thursday, and that number could rise.
Legionnaires’ disease is a serious type of pneumonia commonly caused by breathing in water vapor that contains Legionella bacteria. The disease is most common in the summer because the bacteria thrives in warm water, said Dr. Waleed Javaid, the director of infection prevention and control at Mount Sinai Downtown Network.
Some of the most common culprits in the spread of the disease are cooling towers, humidifiers, hot water tanks and condensers in large air-conditioning units. Whirlpool spas and hot tubs are also sometimes sources of the disease.
In 2015, contaminated cooling towers were the source of a Legionnaires’ outbreak that killed 12 people and sickened more than 120. Legionnaires’ can sometimes contaminate smaller water supplies, as well. In April, three people were diagnosed with Legionnaires’ after the water supply at the Co-Op City complex in the Bronx was contaminated, and one person died.
City health officials said this is the year’s first “cluster” outbreak, in which people across different buildings have fallen ill. Every year, between 200 and 500 people are diagnosed with the disease in the city.
“During a cluster, we’re way, way, way more aggressive than when there’s no evidence of disease transmission from that tower,” Dr. Daskalakis said.
He added that individuals did not need to change their behavior.
“People should drink the water, take showers, bathe as usual, cook as usual, but just be vigilant and persistent and don’t wait,” if flu-like symptoms occur, he said.
“If a person is asymptomatic, they don’t have to worry or panic,” Dr. Javaid said. “Panic is not helpful in this situation if you’re not ill.”
By Thursday, fliers in English and Spanish hung throughout Upper Manhattan. They included a list of frequently asked questions about Legionnaires and a notice to residents: “The risk to most people is low, but if you have flu-like symptoms, please see your medical provider right away.”
Diana Dondrue, 32, said she saw city workers handing out fliers, but she was not overly worried.
Joarty Román, 37, said she was unaware of the outbreak, and was concerned for her elderly parents.
“They should make it more public,” Ms. Román said. “My parents are elderly and I take care of them, so this is something that I should be aware of.”
Mariana Alfaro contributed reporting.
A version of this article appears in print on , on Page A18 of the New York edition with the headline: Legionnaires’ Disease Sickens 11 in Upper Manhattan. Order Reprints | Today’s Paper | Subscribe“
With decreased efficiencies due to scaling, water usage will significantly increase. NOT GREEN.
If one were to perform energy studies, the increased load is alarming. More power and utilities…NOT GREEN
One word. Legionella! The dreaded “L word.” Now, legionella can happen in any system with any treatment program. But with a responsible biocide program, the risk is greatly reduced, and better controlled.
If someone were to contract legionella from a cooling tower for which the owner opted to use a non-proven chemical free form of treatment over a proven EPA registered biocide approach…they will have some tough questions to answer.
If legionella and/or HPC levels get too high, per state and industry guidelines, an EPA registered biocide must be used to resolve the issue. Now we are back to using chemicals. Almost seems like a reactive approach, instead of a proactive or preventative approach.
Causing an environmental and health concern…NOT GREEN!
Instead of jumping to chemical free to “go green”, sit down with your water treater to learn how Chemical Water Treatment is in itself a Green technology!
Make a plan to implement automation to help decrease chemical feed. Work together to increase system efficiencies and reduce water by cycling your cooling tower at its peak efficiency.
Chemical water treatment is proven effective, and when properly administered, truly a Green solution that reduces costs, helps the environment and counts for LEED credits!
Of course, we all want to be as environmentally responsible as we can with our facility cooling systems and treatment programs.
I can see the attraction for going chemical free. But can you take it too far? Is it necessary to go chemical free to be “green?”
Chemical free forms of treatment have been around the industry for years. Many of these have not been proven or do not have a steady track record of positive results. Some almost seem like a late-night TV gimmicky advertisement, promising the world!
We have seen some of these systems work “ok” in specific environments and applications. Great! But we have also seen damage to systems, decreased operating efficiencies, and in some cases, causing environmental concerns such as legionella. Very concerning.
Each of these concerns are the opposite of going green. Ironic, don’t you think?
Here we see the results of a cooling tower left without any water treatment for one year. Solid sediment had built up so thick that it completely covered the hatch opening!!! The tower had become incredibly inefficient, and corrosion had begun to take place throughout the structure.
As you may know, the main function of a Cooling Tower is to help release heat from a building’s HVAC system, a process that can eventually release 75% of the system water to the atmosphere via evaporation, which is replaced with new fresh water. It’s important to recognize that as water evaporates from the cooling tower, dissolved solids and impurities remain behind. These solids will concentrate and increase the scaling, corrosion and biologic growth found in the system. The end result of this process, when left unchecked, is reduced energy efficiency of the HVAC system, as well as damaging corrosion taking place.
An effective water treatment program will focus on regular bleed off of the water rich with accumulating solids, chemical treatment to inhibit corrosion and biologic growth, and regularly scheduled cleaning of the cooling tower itself. These steps will help improve both the efficiency and lifespan of this equipment!
Tower Hatch completely covered by sediment after not having water treatment for 1 year!
With a growing desire to conserve energy, water and other resources, a commonly overlooked option for cost savings is Cooling Tower Evaporation Credits. With the growing costs of fresh water supply and sanitary service, taking advantage of evaporation credits can provide a cost savings towards plant operations budget. Evaporation is calculated by recording water make-up to the cooling tower, then subtracting water discharge via blow down. The difference is water lost to Evaporation. This allows for savings on water that would normally be paid for as sanitary waste.
It is suggested that the customer check with local water authorities to ensure that the water meters and method of recording will be acceptable to obtain the evaporation credits.
Example: A 300-Ton cooling tower running at 4 cycles of concentration uses 1,000,000 gallons of make-up water for a cooling season. The blow down water to sanitary drain at 4 cycles would be 250,000 gallons. This would allow for a savings on sewer charges for 750,000 gallons of water that is evaporated through the cooling process.
For more information about your specific Cooling Tower System and how you can potentially realize Cost Savings thru Evaporation Credits, please get in touch with local Metro Representative.
Metro recently completed the installation of a permanent Secondary Disinfection System (pictured below) utilizing Chlorine Dioxide for a building drinking water system that experienced the persistent presence of the Legionella Bacteria over an extended period of time.
Metro employs Chlorine Dioxide as a disinfectant for Legionella Remediation for its ability to penetrate biofilm and get to the source of the problem, something Chlorine and Bromine can’t do. And as Chlorine Dioxide is generated onsite, no chemicals have to be mixed or stored, making it a much safer option.
Often times, a one-time Disinfection of a piping system is enough to remediate the presence of Bacteria, but in some instances with persistent issues, the permanent installation must be considered.
For more information, please get in touch and we will connect you with your local Metro Consultant.
Controlling the scale-forming tendencies of a cooling tower system is based on regulating the level to which minerals are “allowed” to concentrate through evaporation. Cycles management is one aspect of preventing mineral scale formation on heat exchange surfaces and is carefully coupled to other methods such as: proportionally-dosed application of chemical deposit-control agents, pH control, or even mechanical removal of minerals. Regulating cycles is accomplished by removing some of the concentrated cooling tower water through bleed-off and allowing it to be diluted with fresh “make-up” water while heat is rejected through evaporation. The amount of bleed-off required is based on calculating the allowable cycles of concentration, derived from the saturation limits of the most insoluble dissolved species.Control of cooling water bleed-off is normally done by continuously measuring conductivity of the cooling tower water and tripping a blowdown solenoid or motorized ball valve when a pre-programmed trip point is reached. Make-up water meters with electric contact heads can also be used to regulate bleed-off volumetrically (together with time and flow-rate) to fix necessary cycles of concentration.
Managing cycles and deriving the setpoint at which bleed-off occurs is a very important, balanced consideration. If the set point is too high, minerals will precipitate, and energy costs will rise. If too low, the precious resources water and treatment chemicals are wasted through unnecessary blow-down. So, it is essential that your treatment program be professionally designed, and that the potential obstacles to uninterrupted operation are eliminated. Your Metro water treatment consultant will establish permissible limits of cycles of concentration based on information derived from your facility, including a comprehensive analysis of the local water supply.
Legionnaires’ disease sickened three people in the Bronx in the past year, leading to one death, city health officials said.
The cluster occurred in three buildings that share a water system in Co-op City, which is in the northeastern section of the Bronx. The water supply is being investigated by the Department of Health and Mental Hygiene.
Two of the three people who got the disease were hospitalized and released, while one, who the DOH described as elderly, died.
There are between 350 and 450 cases of Legionnaires’ disease in the city every year, according to the DOH.
Here’s what you need to know about the disease:
What is Legionnaires’ disease and how do you get it?
Legionnaires’ disease is a type of pneumonia that is caused by the Legionella bacteria.
The Legionella bacteria is found naturally in freshwater environments, such as lakes and streams, but when it grows in human-made water systems, like cooling towers, hot water tanks, showers and faucets, it can be a health concern, the Centers for Disease Control and Prevention said.
Having problem with your water softener? Metro can assist your facility in walking you thru a few simple troubleshooting steps.
The most common water softener problem is a poor brine draw. Poor brine draw is typically caused either by a leaking brine draw tube, (flexible tube leading from brine tank to softener head) or a cracked or damaged brine check valve assembly. Item 2 on diagram
Brine tanks and valves should be cleaned out every year, as salt always contains some amount of foreign material, plugging valves and interfering with brine draw.
If indeed the softener is drawing brine well, then an elution study and/or a resin analysis may be necessary.
Contact your local Metro representative for more details!