Cooling Tower Inhibitors

Water treatment for Cooling Towers

An effective water treatment programme needs to achieve a variety of conditions within the system water.  The programme must be environmentally acceptable and comply with any discharge requirements.  A typical programme is not concerned only with Legionella prevention but also needs to control scale, corrosion, and microbiological fouling, based on a thorough analysis of the makeup water and the operation characteristics of the system being treated.

Many regulatory agencies and industry standards require the implementation of water treatment programs, including the use of biocides, to ensure the safety and integrity of cooling tower systems. We provide a complete range for open recirculating, closed circuits and once through cooling systems.

Please refer to the HSG274 guideline when maintaining a cooling tower.

Our Cooling Tower Inhibitor Product Guide

Scale & Corrosion Inhibitors

The scaling or corrosive tendency of a given water can be calculated using the Langelier Saturation Index (LSI) and/or Ryznar Stability Index (RSI). These results are heavily influenced by the hardness of the make-up water. See our graph below to see which of our products are best for your system!

Scale inhibition

As the cycles of concentration within a system increases, the solubility of solids decreases, resulting in scale deposition. Scale formation is due to the precipitation of hardness salts due to excessive total dissolved solids, incorrect pH, exceeding the solubility hardness threshold, and possibly bulk water temperatures.

Corrosion Inhibition

In many cooling systems, a significant proportion of the construction material is mild steel, which is susceptible to corrosion. Although heat transfer equipment may be made of more corrosion-resistant metals such as copper, copper alloys or stainless steel; these metals also need to be adequately protected.  Good corrosion control requires a very clear understanding of the metallurgy and chemistry of the system and system water.

Biocides

Cooling towers provide the perfect conditions for bacterial growth due to the warm and moist environment within the system. Legionella pneumophila, a harmful bacterium, thrives in these conditions and can cause Legionnaire’s disease, which can be fatal. The use of biocides in these systems can help control the growth of bacteria and minimise risk to public health. We suggest reading HSG 274 Part 1: The control of legionella bacteria in evaporative cooling systems.

Packing cleaners

Over time, the packing in a cooling tower can accumulate various contaminants such as scale, dirt, algae, and biological growth. This can severely impact the operation of a cooling tower as it hinders the system’s efficiency by obstructing airflow and reducing the transfer of heat from the water to the air. Packing cleaning should be part of your routine maintenance along with water treatment.

Technical Help

Our expert scientists are here to help with your water treatment needs. Here are a few of our most frequently asked questions. If you can’t find the answer you are looking for get in touch by clicking here

  • A typical cooling tower regime consists of an inhibitor suited to the scaling or corrosion potential of the water, and two biocides, usually an oxidising and a non-oxidising. If you are unsure, we recommend getting in touch with a water treatment consultant to discuss.

  • Scale deposition results in loss of heat transfer, reduced flow rate, strain on the plant, and is a great shield and nutrient for Legionella. All these factors increase the cost of running plant, and so a scale free system is cheaper to run, and has substantially lower risk.

  • The LSI is a great tool to determine the scaling potential and corrosion potential of water in a system. The LSI considers the water’s pH, conductivity, calcium hardness, temperature, and total alkalinity to give you an LSI value = 0, <0 or >0.

    If your LSI value = 0, then your water is considered neutral and should not corrode or scale the system.

    If your LSI value <0 (i.e., -1.5), then your water has corrosion potential.

    If your LSI value >0 (i.e., +1.5), then your water has scaling potential.

The purpose of a cooling tower is to remove waste heat from a system, transferring it to the atmosphere as water vapour, and returning the cold water back into the chiller system. They work by circulating water through the tower onto plastic packing, where the large surface area and exposure to air naturally cools the water. A water management plan is integral when operating a cooling tower to reduce the risk of scale, corrosion, efficiency loss, and bacterial growth, specifically Legionella pneumophila. Our products have been extensively trialed and tested across the UK. Add them to your cooling tower regimen today!

To discuss your requirements and take advantage of our expert advice contact us on 01495 792790.