Water & Wastewater Treatment

Oxygen for Enhanced Aeration & Carbon dioxide for self-buffering pH control

We don't waste water. We renew it.

We develop and deliver customized systems to help industrial plants and municipalities meet their wastewater management goals. We work directly with our customers to provide beginning-to-end treatment methods, from needs assessment and treatment strategy to equipment design, installation and industrial supply. And we offer a wide range of applications that treat and reuse process water, all while maximizing treatment capacity, reducing VOC emissions, improving safety and reducing costs.

But at Praxair, we do more than treat wastewater. As the global demand for potable water continues to rise and fresh water supplies are quickly depleting, we’re advancing industrial technology to make this life-sustaining resource accessible to a growing population. Last year alone, we helped bring clean drinking water to 125 million people around the world.

View our market-specific treatment summaries

Related Pulp & Paper market applications and Praxair services for on-site oxygen production:

Industrial applications for water & wastewater treatment 

Aeration & Odor Control

By incorporating Praxair’s pure oxygen into your existing process, the levels of dissolved oxygen (DO) can be raised enough to reduce odors without further action. As an added bonus, Praxair can provide you with an oxygen treatment system that can help lower your costs, while helping the environment. 

pH Control

Praxair has the resources, experience, technical know-how and supply network to meet your pH requirements. By replacing stronger mineral acids with carbon dioxide, you can lower pH levels more accurately without impacting your safety processes.

UNOX™ Process Upgrades

Explore the possibility of a UNOXTM system process upgrade. Take the next steps to advance your environmental performance. A review of your UNOXTM facility can help you achieve reduced operating costs and improved reliability through the upgrade of oxygen generation and dissolution equipment.


Ozone is a powerful disinfectant used in drinking water and wastewater treatment. Compared to conventional chlorine-based disinfectants, ozone can offer improved destruction of recalcitrant organics, reduced generation of disinfection byproducts and improved destruction of parasitic organisms. In addition, you can avoid chemical residue while controlling unwanted microbial growth in your operation.

Recarbonation & Remineralization

As one of the world’s largest suppliers of carbon dioxide, Praxair offers everything you need for a superior water treatment systems. Praxair can provide a complete analysis and the technical support necessary to determine how much carbon dioxide is required to adequately treat water to a desired pH and restore a balanced mineral level.

CO2 for pH Control and Remineralization case study (1.6MB)

Industrial services for water & wastewater treatment 

Emergency Oxygenation Service

Our In-Situ Oxygenation (I-SO) emergency service can quickly provide temporary oxygen-based aeration to solve water and wastewater treatment capacity problems or excursions resulting from inclement weather, power outages, excessive loading, spills and plant maintenance.

Learn more about our I-SO System

We do more than provide industrial gases, technologies and applications to the water & wastewater treatment industry. We’ll help you to optimize every step of your process. From consultation to implementation and use, we offer a range of services that help you monitor and manage your gas supply so you can focus on making your water cleaner.


Water Treatment Systems 
Ozone And Sludge Reduction

In-Situ Oxygenation (I-SO™) System

Increase bio-treatment capacity with our In-Situ Oxygenation (I-SO) system. This system provides excellent solid suspension, reduces foaming, increases dissolved oxygen (DO) levels, and decreases VOC emissions and odors at a lower cost.  Learn more 

In-Situ Oxygenation (I-SO) System (444KB)

I-SO Installed in UNOX Tank

UNOX  System Process Upgrade 

Explore the possibility of a UNOX ™ system process upgrade. Take the next steps to advance your environmental performance. A review of your UNOX ™ facility can help you achieve reduced operating costs and improved reliability through the upgrade of oxygen generation and dissolution equipment. Learn more. 

UNOX System Process Upgrade (608KB)

pH Control Panels

Carbon Dioxide Control Panels

Using carbon dioxide to replace acid provides a safer and self-buffering method of controlling pH levels. Praxair provides all of the components; engineering, analysis, installation services, product supply and control panels, required to effectively lower the pH level of water. Learn more.

Carbon Dioxide to Reduce pH Levels (109KB)