Cooling Tower Blowdown

Measure & treat scaling ions, treat blowdown

Saltworks solves cooling tower blowdown challenges. We can add novel sensors and controls to your cooling tower to minimize water consumption and blowdown production. We treat blowdown for re-use for cost-optimized freshwater recovery or achieve zero liquid discharge depending on your project needs.

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Cooling Tower Blowdown

Cooling towers are widely used in industrial processes to eject heat. As cooling tower water is cycled and evaporated, total dissolved solids (TDS) and scaling ions concentrate. This accumulation results in the need to periodically ‘blow down’ the cooling tower water and replace it with freshwater. This cooling tower blowdown (CTB) wastewater may require treatment.


More cycling before blowdown, or treating and re-using blowdown water, means lower water consumption and lower net waste volumes generated. Optimizing cooling towers may involve one or more of the following:

  • Targeted removal of specific contaminants-of-concern such as scaling ions or chlorides to enable greater cooling tower cycles.
  • Treat CTB to recover freshwater and produce a low volume brine or even solids.
  • Measuring scaling ions with advanced sensors to safely optimize cycles before blowdown.
Cooling tower steam water
Process diagram of selective removal of silica from cooling tower water

Target Scaling Species

The next step in improving cooling tower performance is to selectively remove troublesome ions, reducing scaling risk and hence reducing blowdown and make-up volumes.


Target silica with SilicaSelect: SilicaSelect removes silica, and as a positive side effect de-saturates gypsum (calcium sulfate). It filters solids to 0.1 µm, making SilicaSelect RO-friendly. SilicaSelect is compact and all solids emerge as a solid filter cake for ease of disposal.


Remove scaling ions with BrineRefine: our automated chemical softening system can selectively remove many more scaling species such as calcium, sulfate, and silica. Run your tower at higher cycles as a result.


Treat chlorides and scaling ions with FlexEDR Selective: remove scaling ions or chlorides with an electrodialysis reversal (EDR) kidney loop.

CTB Treatment Options

Treatment of blowdown wastewater allows for recovery of freshwater and reduces the volume requiring disposal.


Treat blowdown with XtremeRO: our next generation reverse osmosis systems treat CTB. When combined with BrineRefine, up to 99% freshwater can be recovered, producing a very low volume brine. Successive steps in recovery add cost. An economic optimum exists for each site, which we can help you to work out.


Achieve ZLD with SaltMaker: our family of advanced evaporator crystallizers turn low volume brine into solids to achieve zero liquid discharge. Combine cooling and brine concentration into a single step with SaltMaker AirBreather. The AirBreather is a low-temperature, open-to-atmosphere evaporator. If a client requires the combination of cooling (~60 °C) and brine concentration, AirBreather can complete both simultaneously.

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Cooling tower blowdown virtual anti-scalant

Real-Time Scaling Risk Monitoring 

An accurate, real-time measurement of scaling ions means that real scaling risk—rather than assumed risk—can be known. For scaling ion-limited towers, this ensures that blow downs are neither too early, nor too late, allowing safe reductions in freshwater and anti-scalant treatments while preserving the health of components such as the heat exchanger. 


Optimizing performance with ScaleSense: Saltworks’ has developed new real-time sensor technologies that can measure the concentrations of scaling ions, even at high-TDS. A robust, real-time sensor is the lowest cost, first solution.


Contact us to learn more about how your cooling tower performance can be enhanced and for blowdown treatment options. 

Cooling Tower Blowdown Related Products


An automated, real-time sensor for saline water that measures calcium (Ca2+), barium (Ba2+), sulfate (SO42-) ions and silica (SiO2). ScaleSense is robust and corrosion-resistant and functions accurately and precisely, even at extremely high-TDS. More ...

SilicaSelect: Targeted Silica Extractor

SilicaSelect removes silica from wastewaters such as RO brine or cooling tower blowdown. Use SilicaSelect to improve RO recovery, increase cooling tower water cycles, or treat oil & gas produced waters. More ...

SaltMaker AirBreather Evaporator Crystallizer

The first evaporator-crystallizer with no atmospheric contact, important for water with volatile organics. Choose between no liquid water return or clean water that is safe for discharge. More ...

XtremeRO/NF Brine Concentrator

Next-generation water-maker and brine-concentrator based on reverse osmosis that achieves extreme freshwater recoveries, enabling cost-effective brine management and treatment of challenging organic-laden waters including oil & gas produced waters. More ...

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