DECHLORINATION AND SORPTION OF TCE AND PCE IN SOIL AMENDED WITH FLY ASH

Dehalogenation of anthropogenic organics such as tetrachloroethene (PCE) and trichloroethene (TCE) is widely recognized as a means of detoxifying contaminants in the environment. Fly ash derived from electric power generation when land applied can improve the water holding capacity of coarse-textured soils, and alkaline ash can serve as a soil liming agent. In the current study, the ability of an alkaline and acidic fly ash to sorb and/or dechlorinate TCE and PCE was evaluated under oxygen deficient conditions using batch equilibration and dynamic flow-through column techniques designed to minimize the loss of such volatile organics. Sediment samples were analyzed using a GC-MS equipped with a purge and trap sampler. Column effluents were collected using a fraction collector that injected directly into sealed vessels and subsequently analyzed using GC-ECD equipped with headspace sampler. Fly ash displayed a significant ability to retain TCE and PCE in batch sorption tests. TCE, PCE and degradation products were monitored in column effluents to determine the ability of ash-amended soils to sorb and/or dehalogenate such compounds.