Air stripping is a process in which dissolved molecules are transferred from water into a flowing air stream. Air stripping is applicable for the removal of volatile organic compounds (VOCs) from contaminated water. There are two types of air stripping equipment, packed tower air strippers, and low profile air strippers.
Packed Tower Air Strippers
Air stripping is most widely accomplished in a packed tower with of air and water. Contaminated water is pumped to the top of the tower and sprayed uniformly across the packing through a distributor. It flows downward by gravity in a film layer along the packing surfaces. Air is blown into the base of the tower and flows upward, contacting the water. The packing provides a very large surface area for mass transfer. Packings are normally made of polypropylene because of many benefits; inexpensive, chemically inert, lightweight and strong. VOCs are transferred from the water to the air and carried out the top of the column.
Low Profile Air Strippers
Low-profile air strippers can be classified into two major groups: multiple sieve-tray style and multiple diffused-chamber style. Carbonair’s low-profile air strippers are in the former group in which water and air are contacted in step-wise fashion on multiple trays. Contaminated water enters at the top and flows downward by gravity. On the way, it flows across each tray and through a downspout to the tray below. The air passes upward through openings in the trays, then bubbles through the water to form a surface of foam which provides extreme turbulence and excellent mass transfer for organic volatilization. Since the water in sieve-tray air strippers flows horizontally across each tray, the traveling path length of water and the required removal efficiency can be achieved by increasing the number and length of the trays. To read more about how a low profile air stripper works click here.