Cooling water treatment plays a critical role in both conserving water resources and maintaining operational efficiency for all types of buildings, from commercial office spaces to shopping malls to industrial manufacturing plants. As environmental sustainability becomes increasingly important to all organizations, they seek new methods to reduce water, energy and chemical consumption in their cooling tower systems. What you might call "the three R's" of cooling water treatment—reduce, replace and reuse—represent a holistic approach to water conservation, ensuring optimal performance while minimizing the environmental footprint of cooling systems and buildings as a whole.

1. Reduce: Lowering consumption through efficient practices

Reducing water usage in cooling systems is one of the most straightforward and effective strategies for water conservation. This can be achieved through several key practices, including optimizing system operations, addressing water losses, and improving control measures.

Minimizing blowdown: Blowdown refers to the wastewater discharged from a cooling tower to control the concentration of dissolved solids. By increasing the cycles of concentration (CoC)—a measure of how much water is recycled before being disposed of—the need for blowdown can be drastically reduced. A higher CoC means that each drop of water is used more efficiently before it is replaced by fresh water, and is the inverse of the percentage of wastewater sent to the drain, as opposed to being evaporated for cooling. For example, raising CoC from 2 (50% blowdown) to 4 (25% blowdown) will reduce total water consumption by 25%.
Fixing leaks and mechanical issues: Overflows, leaks and other mechanical issues are common in cooling systems, but they can lead to significant water loss if not addressed promptly. Regular maintenance and monitoring of these systems ensures that water loss is kept to a minimum.
Wireless monitoring: Implementing advanced wireless data-monitoring systems enables organizations to track water usage in real time. These systems can quickly identify and correct inefficiencies, such as water loss or imbalances in water chemistry, further reducing unnecessary water use.

2. Replace: Utilizing alternative water sources

Replacing potable water with alternative water sources is another effective strategy for reducing freshwater consumption in cooling systems. Alternative sources include reclaimed water, stormwater and rainwater.

Reclaimed or recycled water: Many municipalities offer reclaimed water, which is commonly used for irrigation, but can also be used in cooling systems in place of potable water. By using nonpotable water sources, organizations can significantly lower their freshwater intake and their water bill.
Groundwater and rainwater: In areas where stormwater is abundant, it can serve as a viable replacement for potable water in cooling systems. Additionally, rainwater harvesting systems can provide an intermittent but valuable source of free water. Although these water sources may require some level of treatment before use in cooling towers, they offer an effective way to reduce dependence on potable water.

By replacing potable cooling water with alternative sources, organizations not only reduce their environmental impact, but also lower their water costs. In some cases, using recycled or alternative water sources can even help avoid wastewater treatment costs by evaporating this water in the cooling system, as opposed to discharging it to the sewer.

3. Reuse: Maximizing resource efficiency

Reuse strategies focus on reusing wastewater from other processes within a building, which reduces both water intake and sewer discharge. This approach differs from replace in that it not only displaces potable water, but also reuses internal wastewater sources that would otherwise be discharged to the sewer.

Reverse osmosis concentrate: Many facilities use reverse osmosis (RO) systems for water purification, which generates a concentrate stream as a byproduct. Instead of discarding this RO concentrate, it can be reused as makeup water in cooling systems. This reduces the demand for potable water while also minimizing the amount of wastewater sent to treatment plants.
Deionization discharge: Similar to RO systems, deionization (DI) systems generate wastewater that can be reused in cooling towers. By reusing this DI discharge, facilities can conserve water while reducing city water and sewer charges.
Process wastewater: Cooling systems can also reuse wastewater generated from other processes within the facility. For example, water used in cleaning or manufacturing processes can be treated and reused in cooling towers, further enhancing resource efficiency. This not only lowers water consumption, but also helps facilities comply with regulations regarding wastewater discharge.

An integrated approach for sustainable cooling water management

The "three R’s" offer a powerful framework for sustainable water management in cooling systems. By reducing water usage through improved control and efficiency, replacing potable water with alternative sources, and reusing wastewater from internal processes, organizations can achieve substantial water savings.

Implementing these strategies not only contributes to environmental conservation, but also provides significant cost savings. By reducing the need for fresh water and minimizing the volume of wastewater generated, organizations can lower their operating expenses and improve their bottom line. In some cases, the return on investment for adopting these practices can be realized in under three years.

As water scarcity becomes an ever-increasing concern, particularly in regions prone to drought, adopting the three R’s of cooling water conservation is an essential step toward achieving sustainable business operations. With proper planning and implementation, organizations can play a key role in conserving one of the planet’s most precious resources while maintaining high levels of operational efficiency in their buildings.

The three R's of cooling water conservation: Reduce, replace, reuse