Ozone Cooling Tower Water Treatment

Cooling Tower Water Treatment


For almost 30 years, ozone has been used to remove and prevent the growth of these organisms while reducing contaminant levels (e.g. AOX and COD) through direct oxidation. Contrary to conventional halogen-based biocides, ozone does not produce unwanted by-products such as halocarbons (AOX).

Cooling Tower Ozone

Cooling systems operations entail extensive treatment as they provide an idyllic growth environment for bacteria, Legionella, algae, fungi and molluscs which can adhere to the pipeline, heat exchanger and cooling tower surfaces. Three main areas of concern are identified:

  1. Scaling in heat exchanger units and pipes
  2. Corrosion of pipes and heat exchanger units
  3. Bacterial and Microbial growth

Malpractices in these areas can lead to reduced heat efficiency and potential overall system failure. Important to note that these facets must be addressed together as fixing one aspect might lead to augmented failure in the other one, an example of higher corrosion level of metals by lowering water Ph levels to inhibit scaling.

Ozone acts as one solution to all these aspects without the need to keep experimenting with different chemicals.

Why use ozone in cooling towers?

Ozone is produced on-site from oxygen gas and is introduced directly into the cooling water via sidestream injection. Ozone may also be injected directly into the cooling tower reservoir. Once it is dissolved in water, ozone proceeds to oxidise organic contaminants and microorganisms. The ozone dosing is regulated automatically by the control system of the ozone generator and varies with the water demand. Ozone, combined with suitable corrosion and scale inhibitors, provides the optimum treatment solution for cooling water.

Some of the advantages of ozone:

  • The most powerful disinfectant
  • Very effective control of Legionella
  • Blowdown water complies with the strictest standards for AOX and COD
  • Microorganism growth is prevented
  • Cleaning downtime reduced
  • No harmful by-product formation
  • No storage/handling of hazardous chemicals or biocides
  • Easy integration into existing plants

Avoid the use of chlorine, and reduce your handling costs

Ozone is generated on-site, it does not need to store or transport chemicals

Avoid spills and unnecessary risks and protect the environment

Avoid the use of chlorine, and reduce your handling costs

Ozone Benefits for Cooling Towers

Water treatment for cooling towers is a relatively new application of ozone technology. Ozone is used to treat industrial wastewater, which is typically high in organic matter and contains dissolved solids. It is also used to remove odours and tastes from drinking water. In addition to these benefits, ozone water treatment offers several advantages over conventional cooling tower water methods. These include:

  • Safe and easy to use
  • Effective against mussel growth
  • Very effective in removing biofilms
  • Ozone is effective in a wide pH range
  • Destroys all types of micro-organisms instantly
  • Ozone decomposes organic waste through oxidation
  • Ozone is 3,125 times more germicidal than chlorine
  • Reduced permit costs for discharge of treated water to the environment
  • Environmentally friendly treatment, facilitating regulatory compliance
  • Very effective against Legionella, due to good biofilm removal capacities
  • Ozone requires no additional disinfectants, micro-organisms cannot become resistant to ozone after prolonged use of ozone
  • Low corrosion rates in the system. Reduces the corrosion rate of metals, including copper heat exchangers, because there are no chlorinated compounds
  • Disinfectant with a high-efficiency level (a residual ozone concentration of 0.1 to 0.2t ppm is, in most cases, very effective in keeping the cooling tower and the cooling circuit clean)
  • The insignificant buildup of disinfectant or disinfectant byproducts. Ozone does not leave any chemical residues or disinfectants, at the end of its cycle, ozone decomposes again into oxygen

Operational Savings

The use of an ozone system in free cooling towers entails in addition to the benefits comprising, represent significant savings to the levels of:

  • Reduction of water consumption

  • Reduction of consumables

  • Reduction of anti-scaling and anti-corrosion agents

  • Reduced maintenance costs

  • Remove the costs of chemical biocides storage and transport

  • Reduction of energy consumption due to the increased efficiency of the cooling operation

Related Case Studies

Robust and Reliable Ozone Technology

The standout feature of Ozcon’s ozone solution for cooling water towers lies in its robustness and reliability. In today’s landscape, it’s no longer acceptable for operators and users to face operational halts due to safety concerns like Legionella or inefficiencies such as biofouling formation.

Compliance with Stringent Safety Regulations in Cooling Towers

The cooling tower environment is renowned for its stringent safety protocols. Leakage of flammable gas into power plant surroundings must be rigorously avoided. This is where Ozcon’s patented method of gas distribution, employing a gas-tight anodized aluminium framework, provides a foolproof solution against ozone generator leakages.

Reduced Maintenance Costs

Cooling towers are often situated in remote locations, necessitating substantial expenses for on-site personnel dedicated to water treatment. Opting for maintenance, repair, and regulation personnel on-site involves both time and additional costs. Ozcon’s system requires no preventive maintenance and operates fully automated, facilitating remote monitoring and regulation, thus reducing overall costs.

Full Automation

Complete automation simplifies operations, particularly in environments where not all personnel are well-versed in water treatment equipment operation. Furthermore, Ozcon’s Human-Machine Interface is exceptionally user-friendly, ensuring straightforward operation and diagnostics, even when conducted manually.

Compact Footprint

Given that the ozone system in cooling towers typically resides within its building, Ozcon’s compact technology proves highly advantageous. Its small size even allows for containerization, offering flexibility in installation.

Long-Distance Ozone Distribution

The building or container housing the ozone system is often positioned a considerable distance from the injection point. Here, the naturally high outlet pressure of Ozcon’s ozone gas is indispensable for efficient distribution over long distances.

High-Pressure Efficiency

High pressure is invaluable, especially considering that recirculating water in cooling towers is pressurised. Ozcon’s generators boast high concentrations, facilitating direct ozone injection into water without the need for a Venturi injector. Even when a Venturi injector is necessary due to water pressure exceeding 3 bar(g), our generators’ high concentration significantly reduces the injector’s size, cost, and energy consumption compared to traditional low-concentration methods.

Immediate OPEX Savings

Power plants benefit from low electricity costs, yet obtaining oxygen locally may prove costly. By operating at high concentrations, Ozcon’s generators ensure substantial OPEX savings from the get-go.

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