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1 <br /> 16 3. PARAMETERS AND ASSUMPTIONS WHICH AFFECT THE <br /> UVB SYSTEM OPERATION <br /> 3.1 DESIGN PARAMETERS <br /> The effective operation of the UVB system is based on a number of calculated or assumed design <br /> parameters These design parameters determine the size of the circulation cell and the extent of <br /> the capture and release zones of the UVB well The circulation cell is defined as the distance <br /> from the UVB well to the stagnation point (S) The stagnation point is the outer limit within <br /> which the UVB well circulates groundwater The area of capture zone, top and bottom (B,By) is <br /> the distance in which the UVB well is able to extract groundwater upgradient from the well The <br /> release zone is essentially a mirror image of the capture zone in the downgradient direction It is <br /> the area where groundwater is released after treatment Figure 5 shows what the circulation cell, <br /> capture zone, and release zone would be for the UVB well proposed for installation at former <br /> Exxon RS 7-3942 <br />' 3.1.1 Circulation Cell, Capture Zone, and Release Zone for Former Exxon RS 7-3942 <br /> The capture zone and circulation cell have been estimated for the UVB system to be installed at <br />' the former Exxon RS 7-3942 site using equations developed by Dr Bruno Herrling (199 1) of the <br /> Groundwater Research Group, Hydromechanics Institute, University of Karlsruhe, Germany <br /> The estimates are based on the following assumptions and simplifications <br /> • Only confined aquifer conditions are considered in the estimations <br /> • The aquifer is confined and has a constant thickness <br /> • The aquifer structure is assumed to be radially homogeneous to hydraulic <br />' conductivities One anisotropic horizontal layer is used, and the horizontal layer has <br /> only one vertical and one horizontal conductivity <br />' • The local below-atmospheric pressure field near the well is neglected <br />' • Water density effects are neglected <br /> • The computations assume steady-state conditions <br />' • For estimating the capture zone, only convective transport is considered <br />' The flow parameters for a UVB well include the stagnation point distance S, and the top and <br /> bottom widths of the capture zone, B, and Bb respectively, for an upstream distance of 5H from <br /> the UVB well, where H is the height of the saturated zone addressed by the UVB well <br /> (Figure 5) <br />' WP61 73942 WPI 096 TX 5 4 <br />