A SIMPLE METHOD TO STUDY THE EFFECTIVENESS OF BIOREMEDIATION AIDED, PUMP-AND-TREAT TECHNOLOGY FOR AQUIFERS CONTAMINATED BY NONAQUEOUS PHASE LIQUIDS .2. MULTICOMPONENT SYSTEMS

Environmental contaminants are frequently encountered as mixtures of non-aqueous phase liquids (NAPLs). The dissolution of organic mixtures from the aquifer has been examined with and without biodegradation, Various physical processes involved have been quantified based on the assumptions that liquid-liquid and sorption equilibria are established at the beginning of each flushing; oxygen required for biochemical oxidation is completely consumed by the end of each flushing; and the rate of biochemical oxidation obeys the Monod kinetics for a multi-substrate system, characterized by an oxygen utilization factor. The mass fraction of any component remaining in the aquifer, its aqueous concentration, and the composition of the NAPL have been obtained as functions of the number of flushings (volume of the flushing solution/volume of the aqueous-phase voids). The results of the simulation with the model demonstrate that highly soluble components of the NAPL are mainly removed by the pump-and-treat mechanism while the components of extremely Low solubility are unavailable to the microbes as substrates in a multi-component scenario. Bioremediation, however, transforms a significant proportion of the low solubility compounds after the more soluble components have been removed from the aquifer. The results also demonstrate that the rate of removal of compounds is retarded by the inclusion of a non-soluble component in the mixture.