According to the United States Environmental Protection Agency, cooling towers account for over 50% of water consumption at industrial facilities. This makes cooling towers the prime target for sustainability improvements. If a facility manager does not want to reduce efficiency or risk assets, then they should consider tower makeup water quality and how it affects their systems and implement innovative solutions for optimized water management.
Cooling towers are vital for maintaining process temperatures, protecting equipment, and ensuring operational continuity. Yet the performance and longevity of these systems depend heavily on an underestimated factor: the quality of the water entering the system.
Utilizing Pre-Treatment for Water Quality
Industrial facilities often deal with varied water conditions, seasonal changes, and process contaminants, making consistent water quality management a challenge. To ensure optimal water quality, facilities may need to implement pre-treatment before boilers, cooling towers, and heat exchange processes.
Common pre-treatment methods:
- Filtration removes suspended solids and particulates.
- Best for facilities using surface water, well water, or recycled water and/or with high particulate loads.
- Softening reduces hardness (calcium, magnesium ions) to prevent scale.
- Best for facilities with hard water sources and in heavy industries, such as power plants, chemical manufacturing, and metal processing
- Reverse osmosis (RO) removes dissolved salts and organics.
- Best for facilities aiming for high purity water and increased cycles of concentration, especially in the semiconductor, pharmaceutical, and food and beverage industries
In combination with the previous methods, chemical additions work in all facilities with varied water quality to manage corrosion, scale, and microbiological growth. The choice of pre-treatment depends on the source water and the specific system requirements.
However, by increasing the quality of the water being used for heat transfer, a facility can maximize cycles of concentration (COC) in cooling towers and boilers without compromising system integrity or environmental compliance. In fact, increasing cooling tower COC from three to six can reduce makeup water consumption by 20% and blowdown volume by 50% (United States Energy Department).
Increasing Cycles of Concentration in Cooling Towers
Cooling towers operate by evaporating water to remove heat, and this process concentrates dissolved minerals and impurities in the remaining water. If the incoming water is of poor quality or high in dissolved minerals, it promotes the formation of scale, corrosion, and biofouling, potentially reducing heat transfer efficiency and increasing energy consumption. This can lead to expensive downtime and increased utility costs.
Poor water quality forces operators to lower COC to discharge water from the system and decrease impurities, raising costs and water consumption. With adequate pre-treatment prior to utility or process water, assets can not only be protected but reduce stress on the environment through water and chemical savings.
Figure 1 is an example of a pre-treatment – an RO system – before the cooling tower.
Just like pre-treatment has methods to maintain water quality, utility water and process water have solutions. As an example, it is possible to have specific chemical dosing with scale and corrosion inhibitors, biocides, and dispersants that can increase COC by extending the scale inhibition characteristics of poor quality water. Any chemical treatment should be monitored to ensure operational efficiency, asset protection, and ecological preservation.
Partnering with a competent, established water treatment provider is key to developing a water reduction plan with the common goal of asset protection through well managed chemical use.
Working with a Long-Term Partner
As industries face increasing pressure to improve sustainability, facilities need a long-term water treatment partner who understands and delivers a solution that evolves with any challenge. In regard to increasing COC – and perhaps the addition of innovative chemicals and state-of-the-art equipment – attentive service offers an environmentally friendly holistic approach.
Sites dedicated to sustainability should focus on water treatment solutions that reduce water and fuel consumption, ensuring a minimized environmental impact. As an example, Kurita’s bio-based cooling water solution Tower NG can replace traditional phosphorus-based chemicals. Going a step further, facilities can further research their partners’ value chain emissions – also known as Scope 3 – and overall sustainability initiatives. In this context, water quality is not just a technical concern but a cornerstone of responsible water management.
Improving water quality before the cooling tower is a gateway to smarter, more sustainable operations. By investing in pre-treatment strategies, understanding the relationship between water chemistry and cycles of concentration, and utilizing knowledgeable and sustainable companies, a facility can reduce water consumption, lower chemical use, and extend equipment life.
