Cooling Tower Water Management – Saving Water
Saving water in evaporative cooling towers has become an increasingly important focus for facilities managers and water treatment engineers. With most systems relying heavily on potable water, even small improvements in efficiency can deliver significant benefits. Not only can effective water management reduce operating costs, it can also help conserve valuable natural resources, cut waste, and support sustainability targets. By tackling unnecessary losses and making better use of alternative water sources, cooling towers can be operated in a way that is both more efficient and environmentally responsible.
In this article, we explore practical ways to reduce water use in cooling towers without compromising performance. We look at the different types of water loss and how they can be managed, as well as options for make-up water replacement, pre-treatment, and improving cycles of concentration. The discussion also highlights the role of chemical treatments in controlling scale, corrosion and bacteria, alongside steps to identify and prevent uncontrolled losses such as leaks and overflows. Together, these measures can deliver safer, more reliable, and more cost-effective cooling tower operation.
Evaporative cooling towers
An evaporative cooling tower brings cool air and hot water together, so that the water temperature drops. Some water evaporates during this process. Most of the water used is potable water (water suitable for drinking). Thus, it is important to ensure that water consumption is kept to a minimum, so that demand on water resources is not excessive.
In this article, we’ll look at how optimum water management can be achieved. We’ll also consider treatment of the cooling water to attain the best performance from the tower.
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Can water losses from cooling towers be controlled?
There are two types of water loss that can occur in a cooling tower:
- Controlled water loss
- Uncontrolled water loss
Some degree of water loss is essential for an evaporative cooling tower to operate correctly. Evaporation is key, for example. The other route to water loss is known as bleed-off or blowdown. This process gets rid of mineralised water from the cooling tower that is generated during the evaporative process. If the minerals were allowed to remain in the tower, this would lead to the unwanted formation of scale or sludge. This in turn makes cleaning and maintenance more challenging and increases the opportunity for waterborne bacteria, such as Legionella to take hold.
However, uncontrolled water losses should certainly be looked at and reduced wherever possible. If this does not happen, the cooling tower will go through more water than is necessary. Leaks and overflows are common areas to look for here, but there can be other problems too, such as water splashing when it should not do so.
How to replace cooling water lost via tower bleed-off and evaporation
Both tower bleed-off and evaporation are controlled processes, as we’ve seen, but the losses must still be replaced for a tower to work efficiently. The normal source is potable water, but it is also possible to treat other water sources including wastewater which can be re-used once water quality is improved. This type of water recycling will ensure that less potable water is required for the correct operation of the cooling tower.
Pre-treating cooling water
Pre-treating the water going into the cooling tower is essential to ensure that it is of the best quality and won’t adversely impact the towers operation. Calcium hardness is a key factor here. The harder the water being used, the more likely it is there will be a build-up of scale in the cooling tower which is bad news.
Examining the cycles of concentration
Calculating the cycles of concentration involves measuring the concentration of dissolved solids in the bleed-off water and comparing this to the make-up water added to the cooling system. Removing the solids from the water will allow it to cycle through the cooling system more times. This in turn saves water and raises the water efficiency level.
All this means that less water will be required to add-back into the system and less will be lost to the drains through the process. If the maximum cycles of concentration are reached, this means the cooling tower will use less water, be more efficient and cost less to run.
Treating cooling water with a scale and corrosion inhibitor
A combined scale and corrosion inhibitor can help improve water quality and ensure the tower cycles are increased as well. These inhibitor products are designed to make the calcium and magnesium salts present in the water more soluble. They also make sure the level of corrosion in the tower is reduced to an acceptable level.
Focusing on better cooling tower water management
By targeting water management and ensuring as little water as possible is lost through operation, you can ensure your cooling tower becomes more efficient. It will also use less water, perhaps by switching or re-using other water sources and focusing on improving their quality or by increasing the cycles of concentration.
It’s clear there is a role here for chemical water treatment products designed to improve the quality of the water used in a cooling tower, although of course, this is only part of the equation. Maintaining safety and focussing on good performance, raising it where possible will also reduce the chances of any waterborne bacteria such as Legionella causing problems in the system.
Cooling tower water management support
Managing water use in evaporative cooling towers is about far more than just keeping systems topped up. By focusing on reducing unnecessary losses, improving water quality, and making the most of alternative supplies, it’s possible to achieve safer, more efficient, and more sustainable operation. The result is lower running costs, reduced environmental impact, and improved reliability across the system.
At Water Treatment Services we help businesses across the UK and Ireland get the best from their cooling water systems. Our specialist teams provide expert advice, water treatment solutions and ongoing support to improve efficiency, manage water safety risks such as Legionella, and ensure compliance with regulatory standards. With offices and engineers based nationwide, we can deliver cost-effective, practical solutions wherever you are.
Contact us today to learn how our cooling water treatment solutions can help you.
