CROSS-FLOW AIR STRIPPING AND CATALYTIC-OXIDATION OF CHLORINATED HYDROCARBONS FROM GROUNDWATER

This paper describes air stripping of chlorinated hydrocarbon contamin ants from groundwater in a crossflow air stripping tower and destructi on of the organic compounds by catalytic oxidation. Crossflow strippin g has an advantage over conventional countercurrent stripping. In typi cal stripping operations, the mass transfer coefficient is insensitive to the velocity of the gas stream. The crossflow stripping tower is a geometry that increases the cross section of gas flow while making mi nimal disturbances to the liquid flow, allowing high gas-liquid ratios without flooding, By increasing the flow cross section for the gas st ream, pressure drop (and thus fan power) can be reduced significantly. A field demonstration of the crossflow column was performed at a cont aminated groundwater site, The groundwater was pumped out and sent to two 17-ft-high (5.2-m) towers in a parallel arrangement. One tower was a crossflow air stripper and the other a conventional countercurrent design. The performance of the two was compared. The key organic speci es targeted was dichloroethane, which has a low Henry's law constant, Three different baffle configurations were tested in the crossflow tow er. The results of this demonstration were used to develop design crit eria for crossflow air strippers to be used for destruction of halogen ated hydrocarbons.