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Cooling Towers Water Treatment

What Is High-Efficiency Side Stream Filtration?

High-efficiency side stream filtration is critical to optimizing the water treatment process for cooling towers. Using high-efficiency side stream filtration equipment, you can filter out fine particulate in your tower’s water supply, which is the underlying cause of many cooling tower problems. These ultra-fine particles can clog your cooling tower, interrupt heat exchange, ruin the effectiveness of chemical treatments and cause an increase in biological growth.

What is Side Stream Filtration?

A clean cooling tower is an efficient cooling tower.

Side stream filtration works a bit differently than other water treatment methods. Instead of treating used water after it’s left the tower, a side stream filtration unit will work as an add-on to your cooling tower, continuously filtering a portion of the tower’s water during normal operations.

With this continual filtration, side stream filtration units can remove suspended solids, organic material and silt particles, mitigating the risk of fouling and biological growth. This allows plant managers to better control common cooling tower issues such as scaling and corrosion. You also realize increased water and energy efficiency gains since you don’t have to discharge as much water from the cooling tower, and your heat transfer surfaces are left unhindered by scale.

Beyond helping to continually keep your cooling tower water clean, what’s most attractive about side stream filtration units is that they are non-destructive and don’t take away from your tower’s operations. You can add or remove units based on your needs, all while your cooling tower is still running. Side-stream filtration is a self-contained process that doesn’t interfere with the system, meaning that you won’t need any unnecessary downtime.

When used with quality chemicals like biocides and common corrosive inhibitors, side stream filters will help keep the system much cleaner over time. This reduces the need for mechanical cleaning of the tower’s exchangers, leading to lower maintenance and overall water treatment costs. The true cost of not filtering out fine particulates is often overlook and can save organizations thousands of dollars.

The Importance of High-Efficiency Side Stream Filtration

Fine vs. Ultra-Fine Particles

While side stream filtration units are key to achieving better cooling tower water treatment, you have to choose the right one. Some side stream filtration units will often leave behind ultra-fine particles in the water, which are the root cause of multiple cooling tower issues.

Ultra-fine particulate is somewhat unique to cooling towers, as water particles get more and more concentrated during cooling tower operations.

To understand how fine particles can lead to the problems mentioned earlier, it’s important to know that all of these issues build upon and aggravate one another. Ultra-fine particulate is a major contributor to fouling and biofilm, which leads to increased corrosion in your tower. That corrosion then degrades your equipment, causing added scaling and even more heat transfer inefficiencies. Ultra-fine particulate can also interfere with biocides and other valuable chemicals, making cooling tower water treatment an unnecessarily difficult burden if those particles aren’t addressed from the very beginning.

Sometimes design engineers will try to use bag filters or cartridge filters to help solve these problems, but that’s not a great option. These filters will quickly become too costly and inefficient, especially since you’re dealing with wet operations.

Instead, side stream filtration equipment use layers of granulated sand to trap ultra-fine particles and other contaminants as the water moves through the sand layers.

High-efficiency sand filters can remove particles down to 0.45 microns. Compare that to other filters in Table 1 below. You’ll see that most filters only go down to at most 10 microns, leaving behind bacteria and other common contaminants that fall between 0.5-5 microns.


Table 1: Particle removal levels of common filter types

Since cooling towers require a large amount of air to promote their evaporative cooling methods, the particles in the air are also an issue, leading to further water contamination. The majority of particles that you’ll find in the air are somewhere between 0.5-2 microns.

This is often the same with cooling tower water. A typical particle analysis reveals that more than 90% of your cooling tower water contaminants are in that 0.5-2 micron range.

While any side stream unit is beneficial, only high-efficiency sand filters will get rid of these small particles that can ruin cooling tower systems. Other benefits of high-efficiency side stream filtration include:

  • Reductions in water and energy consumption
  • Reductions in chemical use
  • Lower maintenance costs
  • Productivity improvements and reduced downtime
  • Better control of biological growth

Always make sure to conduct a particle analysis of your water’s contaminants before proceeding with any type of side stream filtration unit. You’ll want to fully understand your particle removal requirements in order to specify the right type of side stream filter.

Better High-Efficiency Side Stream Filtration Units

When choosing a side stream filtration unit, ChemREADY’s professional-grade high-efficiency system filters offer the best continual water treatment solution for cooling towers. These modular, cost-efficient filtration units offer robust designs and no-hassle, “crane-free” installation. They also start working immediately, with no need to build up a filter cake.

ChemREADY’s filters offer the flexibility and redundancy plant managers need to ensure clean cooling tower operations. ChemREADY offers two base units: 70 gallon per min for larger industrial systems and a 30 gallon per min for smaller commercial applications.

The Complete ChemREADY Solution

Side stream filters work best when used with chemical treatments. Here at ChemREADY, our water treatment experts will help you find the right assortment of chemicals for your specific needs.

After we conduct a thorough particle analysis on your tower’s water, our quality chemicals combined with our high-efficiency system filters will help keep your cooling tower running smoothly.