Cooling towers

Fall, cooling tower shutdown !

When fall arrives, it is the appropriate time to close down your cooling tower systems. When doing so, a number of steps need to be taken into careful consideration, such as the cleaning of your cooling tower and the administration of a winterizing treatment.

Magnus has an experienced team of technicians at your disposal to take charge of the inspection and cleaning of your cooling tower.

During winter, open systems with non-functioning piping must be drained to avoid breakage due to ice expansion. During these relatively long periods, metallic surfaces are exposed to ambient humidity and corrode in a drastic fashion.

 As a consequence, deploying an appropriate storage method for these systems is very important. It requires the dosage of the following 3 products, Magcare 707, Magnatrol 41A and Aquafilm T.

As such Magnus offers a complete program to close down your cooling tower in the best possible conditions.

If you want to start the winter period care free and with peace of mind, call us now to reserve your maintenance !


Spring, cooling tower start-up !

When spring arrives, it is the appropriate time to re-start your cooling tower systems. When doing so, a number of steps need to be taken into careful consideration:

  • Cleaning of your cooling tower before start up
  • Preventive disinfection measures
  • Maintenance and calibration of equipment
  • Water sampling for legionella detection.

Magnus has an experienced team of technicians at your disposal to take charge of the inspection and cleaning of your cooling tower: general conditions will be evaluated; cleaning of hot and cold water basin will be taken care of. Sprinklers and drift eliminators will also be cleaned and so much more.

A preventive disinfection procedure will be advised with an effective biodispersant so your system will start without any lingering bacteria present.

Magnus will also take a water sample to test for the presence of the legionella bacteria. Magnus offers in-house laboratory analysis by two means: method by growth on culture medium and DNA based method.

As such Magnus offers a complete program to start up your cooling tower in the best possible conditions.

If you want to start the summer period care free and with peace of mind, call us now to reserve your maintenance !

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Cooling towers, season at risk

The summer period is usually related to the outbreak of legionnaire's disease. For facilities serving the public and industries, cooling towers are often identified as the cause of this problem. Favorable conditions for the rapid growth of Legionella pneumophila  are especially hot temperatures. A slight modification of some parameters, such as a rise in water temperature, a few degrees can lead to uncontrolled proliferation of this pathogen and cause illness.

Monitoring the water quality of your installation by looking for the Legionella pneumophila bacterium is essential for assessing the potential risk of your cooling tower. Fast and accurate analysis of water and biofilm in your installation are available to help the implementation of efficient measures to improve the bacteria proliferation control. To prevent further risk, the Canadian's Revenue Agency believes that the cost of screening for Legionella bacteria can be a deductible expense from income taxes. This expense is allowed because of the risks for your employees and your visitors' health.

Contact us to request a Legionella analysis at 1 800 363-9929 or send us an email.

Consult our cooling tower action plan


Preventive maintenance

Legionella's prevention - best practices

To minimize the risk of legionella's growth, it is important to establish an action plan that takes into consideration the developmental patern of the bacteria and the amplification factors that characterize the system. Some variations may be applicable in some situations, but generally, good practices should include: the maintenance of the system components in good condition, an operation mode that ensures adequate water circulation, an effective treatment program for corrosion, scaling and fouling control; appropriate use of suitable biocides; addition of a biodispersant and finally, regular screening for the presence of the pathogenic bacteria.

Components' maintenance

Maintaining the equipment in good condition implies that the components of the cooling tower's structure are functional and allow, among other things, the limit of water droplets drifting. Drift eliminators must be intact and free from deposits. The presence of mud, scale and corrosion residues must also be removed from the entire network by mechanical or chemical cleaning as required. At least once a year, ideally early in the season for cooling systems, the tower should be emptied, cleaned and disinfected.

Operating mode

It is essential to avoid stagnation of water as much as possible. All unnecessary sections of piping or unnecessary accessories must be removed to prevent the water from being infested with bacteria as it becomes a recurrent source of contamination for the network. The system in operation should take into account the need to maintain the circulation of water on a regular basis to ensure it receives a sufficient treatment dose. Stagnation of about three days should always lead to an appropriate disinfectant treatment.

Corrosion, scaling and fouling control

A water treatment program is required to prevent the accumulation of scale residues, caused by fouling and corrosion. Blow-down equipment and chemical products should be monitored regularly by specific analysis to ensure its performance. Filtration is a good way to prevent the accumulation of mud and harmful debris. To increase efficiency, the installation must  continuously clean the cold water basin of the tower by creating turbulence to drive the particles towards the filter.

Consult our specialized products !

Use of disinfectants

Several biocides are available to control microbial growth in cooling towers and the choice is predominantly based on the network's characteristics, the product's ability to act specifically on legionella, environmental constraints and ease of application. It should also be mentioned that the biocide used, in a shock disinfection mode following detection of legionella, is often different than the one used for the preventative treatment. In all cases, it is important to be guided by a certified specialist as improper application may greatly reduce the disinfectant's efficiency or have a negative impact on the entire cooling equipment.

Use of a biodispersant

Legionella is not particularly resistant to biocides. However, since the bacterium is often situated under deposits and slime or inside other organisms, the bacterium is thus protected from disinfectants. It is therefore essential to break this protective habitat to allow the action of biocides which eliminates potential growth sites. This effect is achieved by the use of a biodispersant, a product which acts as a detergent to remove biofilms. This should be part of a regular preventative treatment program.

JACQUES MURRAY, TP, vice President Applications and Technologies at Magnus Chemical Limited.

Disinfection methods

The treatment technology to control the bacteria’s growth or to disinfect a contaminated cooling system is chosen according to the system’s physical characteristics and operating conditions. Magnus always suggests treatment technologies that have been proven efficient against the Legionella bacteria.

  • Chlorination
  • Bromination
  • Specific non-oxidizing biocides
  • Chlorine dioxide
  • Ozonation

Some of these techniques can be used both as prevention and treatment, and by continuous or intermittent application. Depending on the chosen technology, temporary or permanent installation of equipment may be required. 

The choice of treatment should take into account restrictions relating to the use of the various disinfectants. This includes primarily environmental impact, health and safety risks, compatibility with the inhibiting treatments in place, and the susceptibility of the system components to corrosion. In all circumstances, the objective remains: effective control of the Legionella bacteria whilst maintaining the system’s integrity and performance.


Detection through analysis

Implementation of best practices known to control the growth of Legionella drastically reduces the risk of infection however, the emergence of the bacterium can still occur in a treated system. Impairment of the procedure, a drift of the process' conditions or any other incident which may boost the development of microorganism may leave a fertile ground for the proliferation and possible infection of exposed persons. The screening by specific analysis of Legionella is the ultimate barrier to detect its presence in the water of a cooling tower and adjust the preventive maintenance without delay.

The detection of legionella bacteria must be carried out in the laboratory using a standardized and specific method. Depending on the circumstances, a method by measuring DNA or development on culture area will be preferred.

The method by measuring DNA allows detecting and measuring the population of legionella in the water or in the biofilm by analyzing their DNA. This method gives a result within 24 to 48 hours. It is therefore an extremely powerful tool for the detection and rapid response, which facilitates the application of disinfection processes and limits the exposure during an outbreak.

The culture method is based on the development of bacteria on agar plates with several different types of treatments. It is grown on the culture media and can be counted efficiently after an incubation period of about 14 days. The culture method identifies more precisely the viability and virulence of the bacteria, important clinical information in some cases.

Chemical cleaning

Magnus is a reliable and experienced partner to help you restore the efficiency of water circulation systems where efficiency is corrupted due to corrosion, fouling or scaling. Appropriate cleaning allows to rapidly restore the hydraulic or energetic performance.

Magnus’ professional staff offers the expertise to perform specific chemical cleaning, using simulation techniques in their laboratories, specifically adapted procedures and high performance products.

Clean in place

CIP (Clean In Place) is a method of cleaning piping, vessels and process equipment, without having to dismantle the equipment. This process allows for fast and consistent results, while facilitating the preparation and cleaning work and its rehabilitation process. 

The basic principle of this cleaning procedure is to circulate the appropriate chemical solution, which has the ability to dissolve residues and contaminants, within the affected installations. Extensive experience and relevant expertise are required to select the products and cleaning procedures according to the characteristics of the installation in question. With over 68 years of expertise in this area, Magnus ensures a quick response tailored to your need.

Cleaning of cooling towers

Cooling tower systems play an important role in both manufacturing applications and in comfort cooling. Major problems may appear if the equipment does not reach the required cooling capacity. A decrease in cooling efficiency is usually caused by problems of scaling, fouling or bacterial slime.

Annual preventative maintenance is always recommended and usually includes the cleaning and disinfection of installations, to ensure:

  • the normal functioning of cooling towers
  • the reliability of refrigeration equipment
  • minimization of the risks associated with legionella
  • the reduction of corrosion
  • the longevity of cooling towers and refrigeration equipment

Heat exchangers

Heat exchangers must be kept clear from deposit accumulation to ensure its optimal performance. Our technical services include the inspection of equipment by using specialized tools, residue analysis and laboratory tests with various available technologies, to offer you a solution tailored to your needs.

Our cleaning techniques are designed to suit applications with plate frame or tubular heat exchangers and cleaning formulas are selected by taking into consideration the components metallurgy.

Contact us today for more information.

Consult our Chemicals section

Consult our Equipment section