In hard times, it can be easy to overlook preventative maintenance items. However, your cooling tower’s filtration system is its first line of defense against many issues. Without filtration, the buildup of airborne dirt and pollen can foul or clog the inner workings of your cooling system. These unwelcome intruders are, unfortunately, also excellent surfaces for bacteria such as Legionella to grow.
KEY INSIGHT: Legionella is a bacteria that can cause diseases including Legionella pneumonia and Pontiac fever. It appears in both natural (rivers and lakes) and artificial (cooling towers and fountains) water environments.
Evaporative cooling systems such as cooling towers are widely used for rejecting heat and maintaining temperatures in many applications. It does this by directing high flow rates of air counter-currently to water flow.
Consequently, this also makes cooling towers excellent air scrubbers. Cooling towers can provide cooling for an industrial facility or provide simple air conditioning in a building. Water treatment programs can make a key difference in an operation.
Besides corrosion inhibitors, biocides, and bleed control, filtration is not commonly viewed as a basic requirement for cooling towers. Yet, many cooling tower owners do not employ filtration technology as part of their regular water treatment program. When properly selected and sized, filtration systems can result in trouble-free operation and significant savings in operating costs.
Filtration technologies can range from manual replacement systems, such as cartridge or bag filtration, to more sophisticated automated systems employing sand, vortex, and other methods.
Cooling tower water will be cleaner when filtered, but what does this mean in practical terms for the mechanical system? Here are 5 reasons why filtering cooling tower water makes sense:
Proper filtration removes particulate matter and suspended solids from cooling tower water originating in the environment, piping, or process. This can decrease deposition in the hot water distribution basin, fill, and cold-water sump of the cooling tower. It also reduces blockages in heat exchangers, piping, and other critical process components. In turn, this can mean improved operation of the system with less unscheduled downtime.
Significant energy and maintenance savings can be achieved with the installation of the right filtration technology. Cleaner water can mean decreased deposits, which in turn can translate into greater heat transfer efficiency and lower energy usage. Furthermore, the frequency of periodic cleanings of system components can decrease. The cleaning themselves may take much less time and be easier to perform, reducing maintenance costs.
Filtered cooling tower water may not only minimize under-deposit corrosion but increase the effectiveness of the corrosion inhibitor used. Because the absence of deposits will allow for a better passivation of the system metal, the engineering life of the system will be prolonged. Additionally, less suspended solids in the water can allow for a more efficient use of the inhibitor. This is because it will mostly bind with the system metal and components rather than with the particulate matter.
Similarly to the corrosion inhibitor, the water treatment program biocides and bio-dispersants will benefit from an increase in effectiveness. This is because there are fewer nutrients and organic matter in the water for the bacteria to feed on. In turn, fewer quantities of these products may be required to maintain proper bacteriological control in the system. This can result in chemical savings.
Finally, in line with the previous point, the risk of the presence of Legionella bacteria in the cooling tower water can be minimized due to the increased effectiveness of the biocides and bio-dispersants. Because most filtration systems come packaged with a circulation pump, stagnation and the presence of dead legs in the system piping can simultaneously be eliminated. This further reduces the risk of the presence of these potentially problematic bacteria.
When properly selected and sized, water filtration can be an invaluable part of a cooling tower water treatment system. It can benefit the cooling tower operations in terms of its water quality, mechanical efficiency, and overall operating costs. Poor filtration will result in inefficient costly cooling, increased maintenance, and an increased health risk associated with Legionella.
Proper filtration is a crucial part of water safety. With heightened awareness around sanitization and respiratory health, it is important to consider your cooling system in your safety plan and to educate your teams in current water chemistry hygiene methods.
Learn more about how you can improve your water treatment systems by contacting DuBois
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