Cooling tower water treatment is attracting more attention as large facilities look for practical ways to cut water use without disrupting operations.
Data centres continue to face scrutiny over water demand, particularly in North America. Similar pressure is also building across oil and gas, food processing, manufacturing and power generation.
For many operators, cooling towers are a practical place to start. They lose water through evaporation by design, but they also discharge water through blowdown to control mineral build-up, scaling and corrosion.
Reducing blowdown can lower the volume of fresh makeup water required. It can also help facilities improve water efficiency without replacing core production equipment.
Cooling tower water treatment targets blowdown
In a conventional cooling tower programme, blowdown helps keep dissolved minerals within acceptable limits. As water evaporates, minerals remain in the system and become more concentrated.
Operators discharge some of that concentrated water and replace it with fresh makeup water. If a facility can safely operate at higher cycles of concentration, it can reduce the volume of water discharged and replaced.
That is driving interest in alternative treatment approaches, including advanced oxidation process, or AOP, systems. These systems use reactive oxidants to reduce organic and biological load in the circulating water.
Cooling towers use a tremendous amount of water, so if you can add something to the system that has no impact on production but a major impact on water use, that becomes a very meaningful place for a power plant to look for savings.
Shawn Ewer, water treatment specialist, Aquagy
AOP offers another route to water savings
AOP is not being positioned as a direct replacement for every conventional chemical programme. Instead, suppliers say it can provide another option for sites under pressure to reduce water and chemical demand.
According to public findings linked to one AOP-based cooling tower system, the US General Services Administration, the US Department of Energy and the National Renewable Energy Laboratory reported average water savings of 26% and a 50% reduction in maintenance.
The Cooling Technology Institute has also described AOP-based treatment as a way to support cleaner and more stable cooling tower water with fewer operational variables.
Traditional chemical treatment is still a large part of what we do, but we never saw AOP as a competitor. We see it as another tool in the tool belt, especially for clients looking for measurable impacts on water and chemical savings.
Shawn Ewer, water treatment specialist, Aquagy
Field results point to reduced makeup water
One cited deployment at the Denver Federal Center, a 600-acre campus used by more than 20 federal agencies, reported a reduction in average annual makeup water of more than 527,000 gallons. That equated to water savings of 26.3%.
The same project also reported cleaner condenser tubes and lower maintenance costs.
A second example from a large Midwest food and beverage facility reported an increase in cycles of concentration from seven to 10. Blowdown fell from 75 to 50 gallons per minute, saving around 36,000 gallons of water per day.
Cooling tower efficiency becomes a strategic issue
Aquagy said it has seen similar performance at a natural gas-powered electric plant in the northeastern United States.
After more than 10 years of using the Clear Comfort technology, we’ve seen the facility reduce its chemical footprint by more than 90% and cut water consumption by more than 25%. The fact that the system can be installed without shutting the plant down makes it even more attractive for facilities looking for savings without disrupting operations.
Shawn Ewer, water treatment specialist, Aquagy
Reducing blowdown does more than conserve water. More stable water chemistry can reduce treatment complexity, lower reliance on corrective chemistry and ease the maintenance burden associated with fouling and unstable cycles.
For facilities balancing water conservation, uptime and cost control, cooling tower water treatment is moving beyond routine maintenance. It is becoming a more strategic operating decision.
More coverage of industrial water efficiency is available in the H2O Global News industrial section, including recent reporting on water savings at an LNG facility.
FAQs
What is cooling tower blowdown?
Cooling tower blowdown is the controlled discharge of concentrated water from a cooling tower to manage dissolved minerals, scaling, corrosion and biological growth.
Why does reducing blowdown save water?
Reducing blowdown means less water is discharged from the system. This also reduces the amount of fresh makeup water needed to keep the cooling tower operating.
What is AOP in cooling tower water treatment?
Advanced oxidation process, or AOP, uses reactive oxidants to reduce organic and biological load in cooling water, helping support more stable water chemistry.
Can AOP replace conventional chemical treatment?
AOP does not replace every conventional programme. It is an additional treatment option for facilities looking to reduce water use, chemical demand and maintenance burden.
