What is Cooling Tower Water Treatment – A Guide

Cooling Tower cleaning

In industrial facilities that use cooling towers, a water treatment system is usually required to ensure efficient operation and extended equipment life. Without proper treatment, cooling tower water can become contaminated with organic matter, form fouling, scale, and corrode, reducing production, resulting in downtime, and requiring costly equipment replacements in the future.

What is a cooling tower water treatment system?

Essentially, your cooling tower water treatment system removes impurities from your cooling tower feed water, circulation water, and/or blowdown water. There are several factors to consider when planning your water treatment system, including:

  • How is your cooling tower set up (open circulating, once-through, or closed-loop)?
  • Do you have quality feedwater?
  • Does your cooling towers and its equipment meet the manufacturer’s specifications?
  • The chemistry and make-up of your cooling water
  • What are the regulatory requirements for discharge
  • The type of heat exchanger
  • What are the stages of concentration?

How Does Cooling Tower Water Treatment Work?

A combination of filtration technologies and chemical treatments help maintain the quality of water in the cooling tower and – if executed well – reduce the levels of bacteria, scale and mineral deposits, and corrosion. However, water treatment alone does not constitute an effective cooling tower maintenance program. Even the best-treated towers must be manually cleaned and disinfected as part of the cooling tower treatment program.

Upgrade Your Filtration and Ultrafiltration Systems

Most cooling towers use filtration systems as the first level of water treatment. In these filtration systems, the water passes through smaller and smaller spaces. Each filter has holes, with the first having the most significant gaps. The mesh filter traps large particles like sediment, rust, and organic material as water passes through. A system of filters is necessary for your filtration when particles are smaller than gaps. Filters with an electrical charge can attract and hold minuscule particles in the final stages when the contaminants are microscopic. Clean,  unpolluted water is the result.

Adjust Your Cooling Tower’s PH Levels

Cooling tower make-up water replaces evaporation, bleed, and leak losses. Sources include city water, well water, and even surface water. How clean your water is and the total volume of make-up water into the system will determine the level of water needed. You may need to adjust water hardness or soften it and balance the pH of the water here to prevent corrosion and regularly test for bacterial volume to mitigate any issues.

Pay Attention to Your Waters Mineral Contents

Mineral content in the cooling tower water, such as magnesium, calcium, or iron, can affect cooling tower lifespan and efficiency. Measuring and remediating “hard” or “soft” water is essential to overall system health and longevity. Lime or resin can be used to soften your water, but keep in mind that adding specific minerals – or removing them – will impact the overall quality of the water and may have undesired effects.

Remove Contaminants with Blowdown Treatments

Blowdowns are part of the regular maintenance of cooling towers. The blowdown is a way to remove water from the system that has accumulated heavy mineral content or chemicals content. Water is then replaced with freshwater, and the spent water is disposed of. Some cooling towers may use reverse osmosis or other water recycling methods even when the water has already been cleaned, opening the tower to new contaminants. Demineral action is often used to remove contaminants that reenter water during treatment, and levels of minerals would be tested after blowdown.

Don’t Forget Descaling and Disinfection

No matter how good your water treatment program is, your cooling towers will require manual cleaning as part of a maintenance program. Serious issues such as scale formations on the fill or Legionella bacterial growth within the system may become prevalent without proper cooling tower cleaning services. Ensure the cooling tower is appropriately cleaned and maintained to maintain optimum safety and operation.

Why Should You Treat Your Cooling Tower Water?

Treating cooling tower water is akin to treating municipal drinking water. Without it, water quality suffers and can cause significant health and system damage. Treating cooling tower water with inhibitors, anti-bacterial agents, and other chemicals can help reduce health risks and reduce the time involved in cleaning.

Dirty cooling tower water can be filled with slime, algae, sludge, and mud, all of which gather on the basin floor and can become a breeding ground for Legionella bacteria to thrive. Properly cleaning your cooling towers can help prevent this from happening and create the safety of your cooling tower.

Dirty water can also negatively impact your chiller’s efficiency, which will, in turn, increase your energy costs. Cooling towers that perform at their optimum level achieve the best results. Minor defects or damage, however, can put a strain on an undertaking, leading to expensive repairs and high running costs if not addressed. We’ve broken down the steps to effectively treating your cooling tower water below. 

What Types of Chemical Are Used to Clean Cooling Towers?

To disinfect, consider disinfecting the cooling tower surfaces after cleaning them with a product explicitly labeled for HVAC use, which is EPA registered. This can prevent microorganisms from flourishing between cleaning cycles. To prevent the development of Legionella bacteria, the BioSpray Tower works well on non-porous surfaces. The disinfectant kills 99.9% of the Legionella that develops in cooling towers.

To descale, consider using a unique ultra cling formula that finds the mineral scale and dissolves it on contact. A descaler with low viscosity and an acidic base will adhere to and descale mineral deposits from cooling tower fill or other vertical surfaces.

Next steps

Click here for the complete line of Cooling Tower Maintenance Solutions from Goodway.

Watch our webinar on Cooling Tower Fill Descaling. 

Read up on our nine tips for controlling Legionella in your cooling towers.


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