Laserfiche WebLink
1 s � <br /> MANAGEMENT OF A HYDROCARBON PLUME USING A <br /> PERMEABLE ORC*BARRIER <br />' Jeffrey G. Johnson (GRAM, Inc., Albuquerque, New Mexico) <br /> Joseph E. tJdencrantz (M-S Environmental, Newport Beach, California) <br /> ABSTRACT: A "permeable oxygen barrier" was formed by depositing 342 <br /> Oxygen Release Compound (ORC) filter socks in a series of 20 six-inch polyvinyl <br /> chloride (PVC) source wells. The objective was to increase the dissolved oxygen <br />' (DO) levels of the aquifer and to enhance the intrinsic bioremediation of dissolved <br /> phase benzene, toluene, ethyl-benzene, and total xylenes (BTEX) contamination. <br />' The DO and BTFX levels were monitored by sanspling morutor points attached at <br /> three depths to the exterior of the source well screens. Additional monitoring <br /> points downgradient of the barrier were also sampled The change in DO <br /> concentrations was determined by contouring the distribution of DO at different <br /> times in a crass-.section view across the front of the barrier and in a plan view to <br /> detc=e the area affect. The same approach was used for estimating changes in <br /> the total BTEX in the aquifer The results of the analysis showed an increase in DO <br /> above background levels, both at and downgradient of the barrier, and an overall <br /> decrease in BTEX. The iridal degradation half-life of benzene after ORC' addition <br />' in the vicinity of the barrier was, approximately, 50 days. <br /> INTRODUCTION <br /> At the request of the New Mexico Environment Department (Nh=), <br /> GRAM, Inc , in conluncnon with Regenesis Bioremediation Products, conducted <br />' a pilot study from August through December 1994 The purpose of the pilot study <br /> was to determine, under field conditions, the ability of ORC to increase the DO <br /> levels in tl%e aquifer. The pilot study consisted of the mnstallation and sampling of <br />' one 6-inch PVC ORC' source well, 26 downgradient morutonng points, and three <br /> existing monitor wells. Ground water samples were collected at vanous times to <br /> determine changes in DO and Er= concentrations. The results of the pilot study <br />' showed that oxygen was released into, and dispersed through, the subsurface as <br /> indicated by an increase in DO at the source well, and downgradient of the source <br /> well, and that remediation occurred at various points in the system as indicated by <br /> a decrease in BTEX Based on the results of the pilot study NMED granted <br /> perrrussion to proceed with the installation of a full-scale remediation system. <br />' Site Description. The site selected for conducting the investigation was the <br /> location of a former filling station in Belen, New Mexico. 'ne site is referred to <br /> as the Shell North Main site by NM= and is approximately 50 km south of <br /> Albuquerque, New Mexico 'Dere was a release of an undetermined amount of <br /> regular gasoline over an unknown period of time at the site A series of <br />' imesaganons had previously determined that dissolved phase contamination in the <br /> 170 " d d6Z = 90 66-tIT -Dea <br />