| dc.description.abstract | A Horizontal Reactive Media Treatment Well (HRX Well) is a novel groundwater remediation technology, which comprises a horizontal well filled with reactive media. Point Velocity Probes (PVPs) were installed in a pilot HRX Well system for treatment of trichloroethene in a silty-sandy aquifer at Vandenburg Air Force Base. The PVPs supported evaluations of the HRX Well hydraulic performance. The PVP design and reactive porous medium were customized for the site. First, hydraulic conductivities (K) of reactive treatment media mixtures were measured in the laboratory using grain size analysis methods, permeametry, and a field scale column test (comparable in size to an HRX Well cartridge). Sixteen grain size algorithms were used to estimate K. The USBR, Slichter, and Shepherd methods, applied to a variety of iron and sand mixtures, agreed well with permeametry and field scale column, producing K estimates that fell within 30 and 60 m/d. The shape, length, and width of the prototype PVP probes did not affect the accuracy of velocity measurements, compared to ±20% differences in porosity between packings. However, two-dimensional (2-D) modeling indicated that a probe occupying more than 16% of the cartridge/column cross-sectional area would cause measurable effects on seepage velocity. Field trials involving the PVPs resulted in accurate seepage velocities measured in the HRX Well, as indicated by 2-D and three-dimensional (3-D) modeling. In addition to supporting the HRX technology, the work performed in this thesis contributed to the broader scientific issues of scaling hydraulic properties measurements from the laboratory to the field of engineered porous media, elucidating hydraulic properties of mixed porous media, simplifying 3-D flow systems to 2-D in radial and cartesian coordinates, and demonstrating direct effects on seepage velocity by desaturation of sandy porous media. | |
