Although any device that promotes contact between air and water strips some volatile compounds, air strippers are usually packed towers or
tray towers operated with countercurrent flow of water and air. The countercurrent flow removes particles from the water and into the air. This process is known as volatization or air stripping. Water is deposited into the system through the top and air is ventilated in through the bottom. Water that reaches the bottom of the system is typically considered treated, but additional testing may be done to determine if it is safe for consumption. Since many of the compounds stripped are
hazardous air pollutants, the air exiting a stripper may require emissions control.
Carbon adsorption is often used and
catalytic oxidation is another option. There are mainly two different types of air strippers: Packed tower systems and sieve tray systems. Different types of air strippers are used depending on the type and amount of contaminants found in the water source being extracted. Packed strippers also work more efficiently in removing lower volatility organic compounds than tray strippers. Furthermore, packed tower strippers are more cost effective than tray strippers when treating larger quantities of water. Towers can be between 5 and 12 meters in height and are typically permanent installations. Though, some towers can be transported on a movable trailer to be used in different areas where water treatment is needed.
Tray Tower Strippers Sieve tray towers use a similar process to packed towers, but instead of packed materials being evenly distributed, the materials are separated into several trays with holes that allow water to drip through them. An electric
air compressor is typically positioned at the bottom of the system where the air from the fans travels through the holes and becomes exposed to the water. A natural draft can also be used as an air source to separate contaminants from the water. A natural draft is used for removing more volatile substances such as
hydrogen sulfide, radon, or
vinyl chloride. On the other hand, mechanical air compressors are used to remove less volatile substances. == Duration of Time Required for Treatment ==