OSEC for Cooling Towers

On-site Hypochlorite Generation Solutions in Cooling Tower Applications

OSEC® Systems

On-site electrochlorination provides valuable security of supply by generating a sodium hypochlorite solution on-site, on-demand for the treatment of water. Electrochlorination produces a sodium hypochlorite solution through the electrolysis of salt (brine). The safe and simple method is widely adopted by water utilities, commercial pools, datacenters, cooling towers, and more, to eliminate harmful microorganisms in water and has several advantages over other chlorination and other treatment systems. Key among these advantages are safety and sustainability. Chlorination via onsite electrochlorination can simplify your process and allow you to focus on your production.


What is the OSEC® System and how does it work?



OSEC systems generate a low pH sodium hypochlorite solution by electrolyzing a brine solution directly on-site. The resulting solution contains <1% sodium hypochlorite and can be dosed directly into the water system. The sodium hypochlorite is prepared as it is needed with no long storage periods. OSEC systems provide you a powerful chlorine oxidant in a simple and sustainable process. The only chemical required on-site is salt which is non-hazardous and can be conveniently purchased in 25 kg bags or as a powder by road tanker deliveries. It is also widely available from many suppliers which ensures security of supply. With insufficient treatment of the water used equipment surfaces and process infrastructure can be corroded. When the water used in the cooling process is treated by best practices you can REDUCE:

  • Energy Consumption (PUE)
  • Water Consumption (WUE)
  • Operational Costs
  • Down Time
  • Compliance Issues


Rendering of OSEC® L Installation


Benefits of On-Site Electrochlorination in Cooling Tower Applications


  • Effective and proven in treatment applications globally
  • Mitigation of safety risk
  • No handling of dangerous chemicals: Just Salt, Water, and Electricity
  • Storage of low quantity of disinfectant for economic production according to demand
  • Negligible impact to PUE performance
  • Effective treatment, minimizing risk of cooling shutdown
  • Hypochlorite solution at stable concentration always available*
  • Ability to innovate by leveraging “reclaimed water”
  • Improved of accessibility to raw materials
  • Operational independence

*Unit annually tested by NSF 61 Standards, validating performance at .7% concentration of sodium hypochlorite


Safety and Operational Challenges with “Bulk” Sodium Hypochlorite


• Rate of accidents are on the rise
• Need to rely on suppliers and drivers, in addition to maintaining best practices on site to ensure safe handling of bulk hypo
• Accidents can cause shut downs and can even result in serious human harm, including death

• Off gassing can arrive at the pump head causing Pump Binding
• Off gassing/expansion in piping can cause binding or leaks
• Risks with degas valves, which are necessary for lower capacity bulk hypo pumps to vent the gas that makes it to the pump head
• These issues can lead to extended down time, more regular maintenance intervals or even accidents.

• Eye Contact: NaOCl can irritate & burn the eyes
• Skin Contact: NaOCl is corrosive, causing burns and irritations that can worsen with time
• Inhalation: Can cause headaches and respiratory issues, sometimes severe

• Through the degradation of bulk hypo we can see Formation of Salt crystals
• The formation of salt crystals can bind equipment or make maintenance challenging.

Safety Highlight
With OSEC® Systems you do not need to handle NaOCl, as it is made safely with just water, salt and electricity!

Degradation with Bulk Sodium Hypochlorite

Benefit Highlight
You can attain reliable, proven, and more cost-effective treatment with OSEC Products!

Safety and Operational Enhancement with OSEC



  • Government agencies around the world have identified chemicals, at higher concentrations, to be a large security risk to facilities and the surrounding communities where shipments pass through.
  • There is also security through improved accessibility of salt, water, and electricity.


  • Only operate the OSEC unit when you need to based on the realistic demands of the facility. This can present waste and improve seasonal demands.


  • Bulk Hypo has a higher pH than OSEC system and potable water, thus can start to raise the overall pH and creating more OCl- ions, reducing the efficiency of the disinfection process.OSEC-pH-Imact-Graph


  • Salt storage is easier, safer, and more reliable storage than the same time period for hypo.
  • In a pinch or challenging times (weather, etc), solar salt can be available from many local retail locations.
  • OSEC systems simplify disinfection storage and give greater operational flexibility when necessary. Sustainable through Independence.
Safety Highlight
With OSEC® Systems, operation is more efficient, safer, and sustainable.

Unique Features to the OSEC® L System

  • Economical consumable cartridge design increases safety and maintenance costs as you do not need to be clean via acid wash.
  • No special tools required and easy access to all components simplifies installation and maintenance.
  • The 93% efficient rectifier for each individual electrolysis cell reduced power consumption and prevents downtime and creating a safer more efficient design
  • Feed lines and brine dosing pump for precise brine metering to ensure the unit is delivering the desired product.
  • Electronic module, with 4.3 "graphic color display with Ethernet interface Modbus® TCP, allowing for easy access onsite and remote. Provides a sense of security and safety through simplicity.
  • Product sampling point, for ease of analysis, making the routine operation simple.
  • The OSEC L® system provides market-leading salt and power efficiencies offering performance.


OSEC is a trademark of Evoqua Water Technologies LLC, its subsidiaries, or affiliates in some countries. MODBUS is a trademark of Schneider Electric.

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