ARCHIVED REPORTS XR0011176 - Laserfiche WebLink

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REMEDIATION TESTING AND DESIGN March 12 , 1993 Soil Gas Survey In order to investigate and characterize the general extent and shape of the gasoline plume in shallow soils , a limited soil gas survey ( SGS ) is Proposed The SGS will generally consist of the installation of 10 temporary vapor extraction probes The proles will be constructed of Schedule 60 3/4-inch diameter carbon steel F)ipe Each probe will contain a 36-inch range of 3/16-inch driller? perforations at one end with a forged point All probes W-- l- b6 steam cleaned prior tc use They will be hydraulically driven depth of , but not more than, approximately twenty feet below ground surface Depths of probes will be determined in the field by the registered seologist from RTD and by a representative of Ultramar , Inc based on east boring log data , Following installation, a Pump induced vacuum will be applied to each probe to purge resident soil gas Sample purge rates and vacuums will be monitored and recorded for each probe. Soil gases from the probes will be analyzed for total volatile hydrocarbons (TVH ) using an organic vapor analyzer (OVA) or a flame ionization detector (FID ) In addition , RTD will collect soil gas samples in one liter Tedlar bags from up to five probes to be sent to a certified laboratory for analysis of total petroleum hydrocarbons as gasoline (TPHg ) and benzene , toluene , ethylbenzene and total xylenes (BTEX ) The soil" gas TVH data will be mapped on a scaled site plan to aid in the evaluation of gasoline source areas and migration pathways Upon completion of the SGS , the probes will be used for the VEFT Following the VEFT, certain probes will remain in the ground to be .utilized in a vacuum extraction remediation system. The probes that will be removed will have the probe holes sealed with Portland cement slurry The probes left in the ground for the vacuum extraction system will be capped by RTD prior to RTD leaving the site Ultramar, Inc contractors will , within one week, connect the probeW to lateral piping, provide a sanitary seal and cover each F-robe with a vault box with a locking lid. They have also stated that there will be a permanent six foot fence surrounding the property. RTL and Ultramar have extensively discussed the limitations and potential dangers associated ,with driving temporary probes . Given these limitations , Ultramar, as our client and site owners , is entirely responsible for selecting probe locations . All probes driven by RTD will be at the direction of Ultramar. RTD reserves the right to refuse to drive any probes at its sole discretion. ' Vacuum Extraction Feasibility Testing A VEFT using the e-isting -)n site monitor wells , vapor recovery 'qe?lS and temporary prObes will be conducted to determine the effectiveness of� using vacuum extraction for remediation of sows ,+ groundwater and removal of insoluble hydrocarbons ( if present ) . 2