Using Air Strippers for Off-gas Treatment

Two pharmaceutical plants in Puerto Rico used large sequencing batch reactor (SBR) systems to treat their wastewater. The primary treatment was an aerobic bio breakdown of the waste. They were forced to change their treatment process because of change in treatment regulations. The new regulations required them to treat off-gas coming from the SBRs. They were faced with installing a very large catalytic thermal oxidizer (CATOX) to treat the off gas.

They created a concept to see if they could pre-treat the gas with a much more efficient tray stripper on the wastewater side before it entered the SBRs, they could use a much smaller CATOX unit. In essence, remove the volatiles with a smaller air flow rate before it entered the CATOX. They used two of QED’s 250gpm E-Z Tray® (U.S. Patent Number 5,518,668) units. This is an interesting case where the air stripper are not being used as the primary treatment method, but to treat the off-gas. This result gave major cost savings by including the E-Z Trays in the process stream.