Why Side Stream Filtration is Essential for Cooling Towers

Cooling towers play a crucial role in industrial processes by efficiently removing heat from cooling water systems. However, during operation, cooling water absorbs large volumes of airborne particulate, including dust, microorganisms, and debris, which can accumulate and negatively impact the performance and lifespan of the system. The system pipework may also be a contributing factor owing to corrosion, biofilm, and scale build up. To address this issue, high-efficiency side stream filtration has emerged as a critical component in optimising water treatment for cooling towers, improving biocidal efficacy and overall safety from the release of pathogenic organisms, in particular Legionella.

Understanding High-Efficiency Side Stream Filtration 


High-efficiency side stream filtration is a proactive approach to maintaining the cleanliness and efficiency of cooling tower water. Unlike traditional in-line water treatment mechanical methods that focus on mechanical removal of large solids via mesh strainers after it has left the tower, side stream filtration operates as an add-on to the cooling tower and its associated pipework water content holistically – continuously filtering a portion of the tower’s water during normal operations. 

By filtering out suspended solids, organic material, and other particles, side stream filtration mitigates the risk of fouling and biological growth, which are major contributors to scaling, corrosion, and reduced heat transfer efficiency. Additionally, this filtration method promotes water and energy efficiency gains by reducing the need for excessive water discharge from the cooling tower, known as cycles of concentration (COC), reducing effluent water and chemical use – benefits to both carbon and negative environmental impact. 

The Benefits of High-Efficiency Side Stream Filtration 


Implementing a high-efficiency side stream filtration system offers numerous benefits for cooling tower operations:

  • Improved Cooling Tower Performance:  A clean cooling tower is an efficient cooling tower. By removing fine particulate matter from the water supply, side stream filtration enhances both the towers and Chillers Condenser heat exchange capabilities whilst preserving the effectiveness of chemical treatments. This leads to improved overall cooling tower performance, reduced downtime and water savings.
  • Enhanced Water and Energy Efficiency: Side stream filtration reduces the need for frequent water discharge from the cooling tower, resulting in significant water and energy savings. With fewer impurities present in the water, heat transfer surfaces remain unobstructed by debris, improving energy efficiency and reducing operating costs.
  • Cost Savings on Maintenance and Water Treatment: By continuously filtering out fine particulates, side stream filtration minimises the need for mechanical cleaning of the tower’s exchangers. This leads to lower maintenance costs and extends the lifespan of equipment. Moreover, the use of quality chemicals, combined with side stream filtration, reduces the overall water treatment expenses for organisations.
  • Control of Biological Growth: Biological growth, such as fouling and biofilm, is a common issue in cooling towers. Side stream filtration, when combined with appropriate biocides and inhibitors, helps control, and prevent the growth of harmful microorganisms. This ensures a cleaner and healthier cooling tower system, reducing the reliance on expensive and time-consuming cleaning procedures.
  • Flexibility and Non-Interference with Tower Operations: One of the major advantages of side stream filtration units is their non-destructive nature and minimal impact on tower operations. These self-contained units can be easily added or removed based on the specific needs of the cooling tower, allowing for flexibility without any unnecessary downtime. 

Choosing the Right Side Stream Filtration System 


When selecting a side stream filtration system, it is essential to consider the specific requirements of your cooling tower. Conducting a particle analysis of the water’s contaminants is crucial in determining the appropriate micron filtration rating. 

The X-POT XP+ is an all-in-one side stream filter that replaces the need for separate equipment such as:

  • Magnetic Filters – In the primary chamber all magnetic particles are removed by powerful rare earth magnets, all encased in easy to clean 316 stainless steel.
  • Cartridge and Bag Filters – The system water then passes through the stainless steel baffle plate into a secondary chamber where the fine filtration cartridge captures non magnetic debris, biofilm and corrosive micro bubbles.
  • Dosing Pots/Shot Feeders – The tundish/funnel on top of the primary chamber allows for easy dosing of the adequate water treatment chemicals required for the system.
  • Dirt & Air Separators – The automatic air vent removes microbubbles accumulated in the system without the need for manual intervention mitigating problems such as corrosion and inconsistent flow rates.
When selecting an X-POT side stream filter, consider factors such as the nature of the solids being removed, system requirements, and available space. Check out our X-POT configuration tool here 

High-efficiency side stream filtration is a vital component in optimising water treatment for cooling towers. By continuously removing suspended solids and contaminants, this filtration method improves cooling tower performance, reduces maintenance costs, enhances water and energy efficiency, and controls biological growth. Selecting the appropriate side stream filtration system based on particle analysis and specific requirements ensures the longevity and efficiency of cooling tower operations. Implementing high-efficiency side stream filtration systems such as the X-POT is a proactive measure that results in significant cost savings and a more sustainable cooling tower system. 

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