Controlling Scale in Cooling Towers with Hard Water

Eliminating Scale in Cooling Towers for a Manufacturer in Eastern OH

A Chardon Labs Case Study

How Does Hard Water Affect Cooling Towers?

During an evaluation of a cooling tower system for a manufacturer in Eastern OH, Chardon noticed a large amount of scale buildup in the towers.  Calcium carbonate scale most easily can form in situations with harder make up water, meaning there are more minerals in the water coming into the system before it’s used in the tower.  The following case study shows the impact of proper cooling tower control equipment and monitoring, especially in situations where the water coming into the system is harder.

This facility was receiving its’ water supply from a local well, which was had very high amounts of calcium hardness (640 ppm) and alkalinity (300 ppm).  These high of numbers means that “cycling-up” or recirculating the water in the system to be reused, is much more limited.  The other factor that made this system particularly challenging to control scale is that the well water quality varies significantly throughout the year.

preventing scale in cooling tower case study

 

The tower systems at this manufacture had developed a layer of scale due to the variety of issues with the make up water and inconsistent automation.  The bleed valve had also built up deposits to the point of little to no flow, preventing the valve from opening.  This only sped up the scaling in the system given the already hard water, making the cooling tower highly inefficient at ejecting heat.

How Do You Get Rid of Scale On A Cooling Tower?

Given the build-up of calcium carbonate scale in the system, just changing the program won’t eliminate the damage already done by the scale. So, removing the current scale was the first step.  Getting rid of scale can be done in a variety of ways, but in areas of larger build-up, the procedure is typically as follows:

  • Pressure wash the sumps and drift eliminators to remove outer layers
  • Use foaming acid to remove remaining deposits on drift eliminators
  • For tube bundles, using a long-term application like DA-12 to clean those surfaces

using foaming acid to remove scale

Treating Hard Water to Prevent Scale

Chardon put together a proposed plan to help the cooling tower treatment program for the manufacturing facility prevent scale.  To prevent scale growth, proper equipment and monitoring is often the difference in keeping systems scale-free. At this manufacturing facility, Chardon recommended the following changes to the program to control scale growth:

  • Water meter control of inhibitor feed- chemicals are fed on how much water is being used
  • An automated scheduled feed of a biocide to prevent microbial growth
  • Conductivity control for bleed can be vital in controlling scale and deposits in your cooling tower system.
  • Ensuring that the right amount of minerals is saturated in the water so that the program operates as it’s designed every time is important.  With this system, level control was an issue as the towers would overflow and overfeed chemicals, so setting up a reliable overflow monitor was crucial.

With this system having multiple towers and single controllers for each system, an upgrade to a Megatron MT controller would help monitor conductivity, as well as automate feed of inhibitors and biocides for the system.  These changes to the program would drastically reduce the risk of scale in the system and allow the manufacturing process to run much more efficiently without shutdowns.

Having proper control equipment for your cooling tower system especially in hard water situations can save thousands on repairs and energy costs.  Remote monitoring controllers are a proactive approach to see real-time if there are any minerals or deposits forming quickly in your system before it becomes a widespread problem.

To learn more about how Chardon can help control scale in your cooling tower system, contact us today!

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About Chardon Labs

Chardon Laboratories is an employee-owned, ISO Certified Service Company specializing in Guaranteed Water Side Solutions for all your industrial and commercial water treatment needs. Since 1965, Chardon has led the Water Management Industry providing customized treatment programs for cooling towers, boilers and loop systems with guaranteed results.