Having clean drinking water is important to all of us. Without clean water we could get very sick. Fortunately, our cities make sure our water is always clean enough for us to drink safely. One type of water treatment is dissolved air flotation and it is a very interesting process. It essentially uses air to clean the water and actually does a pretty good job. You’d be surprised to find out all the bacteria it kills.

Wastewater treatment is a never-ending process for many municipalities and industrial businesses, such as paper mills, natural gas and chemical processing plants, oil refineries, and other industrial facilities. This includes various types of wastewater treatment systems designed specifically for the treatment of oily water, the treatment of sewage, and the removal of a variety of other solids that contaminate water through a wide range of industrial processes.

Until recently, the “go to” technology for removing solid waste from water has been a technique called dissolved air flotation (DAF). This process involves the introduction of high-pressure air into a tank or vessel containing wastewater, creating bubbles that act to cause suspended solids to float to the surface, where they can then be removed through the use of skimming equipment. In some cases, such as use in the oil industry where DAF presents an explosion risk, dissolved gas flotation, which uses the introduction of natural gas to create bubbles, is used as an alternative.

Today, the next generation of sewage and industrial waste treatment, called Suspended Air Flotation (SAF). SAF offers a variety of benefits compared to conventional DAF, including:

• Equipment size is only one fifth of the size, requiring a much smaller footprint
• Remove more solids and smaller ones
• More profitable
• Converts solids into a gel-like substance that is more easily removed from wastewater

SAF’s improvements over DAF are made possible primarily through a better and more efficient air delivery system. DAF uses small amounts of high pressure air to create bubbles. SAF uses large amounts of air at lower pressure, and each bubble created is covered in a chemical film that makes solids in the wastewater highly attracted to them. DAF is based on inert bubbles that physically trap solids passively, without creating a strong bond. SAF’s chemically charged bubbles actively adhere to solids, causing them to quickly rise to the surface and remain buoyant. By using a lower pressure air supply system, SAF also requires significantly less energy to operate, adding to its cost effectiveness. The implementation of suspended air flotation in wastewater treatment and oily water treatment has been totally successful so far.