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Abstract. An understanding of vapor transport in natural porous media is critical to the assessment of a wide range of environmental problems. In this work a comprehensive experimental program was undertaken to evaluate the relative importance of different gaseous transport mechanisms in natural porous media. The dusty gas model was used as a framework for this evaluation. The experimental program was divided into two parts: the first emphasizes the measurement of porous media transport parameters, and the second explores flux mechanisms in organic vapor transport. Results of the first part are presented in this paper. Single and binary gas experiments were conducted to obtain governing transport parameters (coefficients of permeability, Knudsen diffusion, and diffusibility) in dry porous media. To conduct these experiments, a special experimental apparatus was built that incorporates a diffusion cell that represents an open system where the pressure gradient and absolute pressures can be regulated by controlling the flow rates

Removal of trace organic contaminants from aqueous solutions by air strippers (AS) and fixed bed carbon adsorper (FBCA) has been studied. A trace organic treatment tool has been developed to capture and adapt the best-known design procedures and to have all regulated trace organics, their physical and chemical properties, and the corresponding maximum concentration limits. Outputs include the selected treatment method and the final design parameters of air stripper or fixed bed carbon adsorber. Running the model shows that water temperature is a very important factor in designing AS and FBA. It also shows that the best air pressure values, in AS, ranged between 150 -200 ATM. And there is a big relation between the column size and the packing material. On the other hand, it shows that FBA diameter has an obvious effect on the needed volume, and the best values ranged between 1.2 -2.5 m.

Being one of the largest groundwater basins in Jordan, the Azraq basin is considered to be an important domestic and agricultural water source. Lately, there have been growing concerns about the continuous depletion and deterioration in groundwater quality in the basin due to intensive pumping beyond the safe yield of the basin. This is where assessment studies equipped with the proper modeling tools come into the picture. The highly advanced groundwater model, ParFlow, was utilized in this project in order to model groundwater flow in the basin. ParFlow employs the latest numerical techniques along with the massive power of parallel computing to utilize three-dimensional heterogeneity in groundwater flow modeling. This was tested against the homogeneous assumptions employed in more commonly used models such as Processing Modflow. Modeling results were compared to those produced by the PM5 modeling studies conducted by relevant official agencies in Jordan. Furthermore, the calibrated flow model was used to predict the aquifer system's response to a pumpage scheme of 55.5 MCM/year. The results showed that the maximum drawdown predicted by ParFlow was greater than the amount predicted by Modflow for the same pumping scheme. One of the causes of this difference in predictions may be attributed to the fact that ParFlow gives a general, more comprehensive picture of the system at hand, as opposed to the point dependent results obtained via Modflow. Springer 410 Water Resour Manage (2007) 21:409-425Velocity vector [LT −1 ] K I = Hydraulic conductivity tensor [LT −1 ] h I = Pressure head [L] γ = Constant scale factor (viscosity) [ML −2 T −2 ] V i = Darcy velocity vector [LT −1 ]

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since the method is usually most effective for sandy subsurface conditions. Although some application sites have The successful application of bioventing systems for in situ remediaincluded clay lenses, only in exceptional cases has biotion of petroleum hydrocarbon-contaminated sites depends on many factors including: moisture content, temperature, number and location venting been applied to sites with extensive overburden of injection and extraction wells, as well as corresponding airflow rates. clay or fractured bedrock (Grasso, 1993). The importance of well locations and air flow rates has been exploredGas permeability is probably the most important site in this study and their optimal values were obtained via the fixed well characteristic. Soils must be sufficiently permeable to method. The design problem was formulated to maximize total conmovement of enough gas to provide adequate oxygen for taminant mass removal within a given time frame subject to physical biodegradation (Barr, 1993). When permeability falls beand budgetary constraints. The technique developed herein was aplow 0.1 Darcy, bioventing applicability is not expected plied to a field case study. Results indicate that optimal well locations to be very effective (Grasso, 1993;Barr, 1993; are found along the mass centerline(s) of the contaminant plume. Rathfelder et al., 1995). Furthermore, well location optimization was proven to be more impor-Factors affecting bioventing can be classified into two tant than pumping rate optimization.