CONTINUOUS VAPOR-PHASE TRICHLOROETHYLENE BIOFILTRATION USING HYDROCARBON-ENRICHED COMPOST AS FILTRATION MATRIX

Two sources of finished compost material were examined for the capacit y to support trichloroethylene(TCE)-degrading microbial populations in a gas-phase bioreactor. Gaseous hydrocarbon was passed through the bi oreactor to stimulate cometabolic oxidation of TCE. Significant differ ences in TCE removal efficiencies were observed between the two compos t types, and between hydrocarbon-stimulated and non-stimulated compost . At an average column retention time of 5.6 min, deciduous leaf debri s compost removed more than 95% of a 5-50 ppm (by vol.) TCE gas stream , whereas less than 15% removal was observed under similar conditions with a woodchip and bark compost. Trichloroethylene removal efficiency varied with the hydrocarbon-stimulation regime employed, although pro pane and methane stimulated TCE degradation equally well. Amendment of compost with granular activated carbon substantially increased biolog ical TCE removal. Differences in TCE removal efficiencies observed bet ween the two compost types and between hydrocarbon-stimulated and non- stimulated composts were investigated in terms of changes in the overa ll heterotrophic microbial populations by using community-level physio logical profile analysis.