Heterogeneous granular sediments—sands and gravels —form the most important water-supply aquifers in many areas of North America. In the past 60 years many such aquifers have become contaminated with nonaqueous phase liquids (NAPLs) and the dissolved phases associated with them. These include glacial outwash deposits in New England, Ohio, and Ontario, the floodplain alluvium along the Columbia ...

Assessing human exposure to chemicals from Superfund sites requires knowledge of basic physical, chemical, and biological processes occurring in the environment and specific information about the local environment and population in the vicinity of sites of interest. Although progress is being made in both areas, there is still a tremendous amount to be done. Participants at this meeting have id...

Surfactants are amphipathic compounds having both lipophilic and hydrophilic structural moieties in its molecule. They are mostly produced on microbial surfaces or excreted extracellular hydrophobic and hydrophilic moieties. Due to such nature, solubility of hydrophilic molecules is increased alongwith reductions in surface and interfacial tensions at the oil/ water interface [1]. Surfactants a...

The current regulatory trend towards accepting intrinsic bioremediation as a long-term management scheme for residual organic pollutants in the subsurface for fuel spills is based on statistical evaluations of plume behavior for a limited array of pollutants. The effectiveness of intrinsic bioremediation towards protecting water supplies, and hence human health, is not known for many pollutants...

[1] Numerous observations and laboratory experiments suggest that elastic vibrations can significantly enhance transport of nonaqueous phase liquids (NAPLs) in porous media. Our analyses suggest that in the low-frequency range, capillary forces and nonlinear rheology of the fluid may be predominant mechanisms of vibratory stimulation. Consequently, a model of these mechanisms is built to explai...

Groundwater pollution by Non-Aqueous Phase Liquids (NAPLs) has become an increasing threat. This article studied the steam injection efficiency in groundwater remediation contaminated with non-aqueous phase liquid (diesel) through a bench-scale laboratory experiment. The experimental set up consists of boiler and sandbox. Steam, which was generated from supplied to sandbox at rate 0.14m3/s, pre...

The bioavailability of naphthalene present as a component of a complex nonaqueous phase liquid (NAPL) comprised by nine aromatic compounds was investigated. Specifically, the effects of naphthalene mass transfer from the NAPL to the aqueous phase on rates of its microbial degradation were examined. The investigations were conducted using a pure culture, ATCC 17484, and a mixed culture of naphth...