ARCHIVED REPORTS_XR0010336 (2) - Laserfiche WebLink

Home Browse Search

AS-I through AS-13, and five (5) SVE wells, designated VE-1 through VE-5 The wells will be ialigned in a row extending downgradient from the former UST tankfield to the MW-3 monitoring well cluster near the site property line The remediation system layout for the project site is presented on Figure 9 Aar Sparging Wells and Associated Plumbing Pilot testing well IAS-1 will be re-designated AS-1 and utilized as part of the remediation system An additional 12 AS wells (AS-2 through AS-13) will be installed to a depth of approximately 60 feet bgs This well depth was selected based on the results of the pilot testing and may be adjusted during the installation activities based on hydrogeologic conditions The primary concern is that the depth of the AS wells is 5 to 10 feet below encountered groundwater The additional 2- inch PVC AS wells will be constructed utilizing 5 feet of 0 010-inch circum-slotted well screen and approximately 55 feet of blank PVC riser The annulus of each AS well will be backfilled with 20/40 silica sand to approximately 54 feet bgs (1 foot above the screened interval) The sand pack will be topped with a 2-foot bentonite seal and then capped with approximately 50 feet of bentonite/cement grout, culminating approximately 2 feet bgs Each AS well will be accessed by an 18-in x 18-in steel manway which will be set in a 3-ft x 3-ft concrete pad A gate valve and . pressure gauge will be installed at each manway for the control and confirmation of air delivery and pressure The AS wells will be piped in groups of two to a distribution header for compressed air delivery The only exception will be well AS-7 which will have a separate air delivery line The air delivery lines will be constructed utilizing 3/4-inch steel piping The air delivery manifold will include control valves, in-line rotometers, and pressure gauges to assist in quantifying the operating parameters for the AS wells Soil Vapor Extraction Wells and Associated Plumbing Pilot testing wells VE-1 and VE-2 will be utilized as part of the remediation system An additional three (3) SVE wells (VE-3 through VE-5)will be installed to a depth of approximately 40 feet bgs This well depth was selected based on the results of the pilot testing and may be adjusted during the installation activities based on geologic conditions at the various locations The primary concern will be to maintain the depth of the SVE wells above the current groundwater levels The additional 2-inch SVE wells will be constructed utilizing 30 feet of 0 010-inch circumslotted well screen and approximately 10 feet of blank PVC riser The annulus of each SVE well will be backfilled with 20/40 silica sand to approximately 9 feet bgs (1 foot above the screened interval) The sand pack • will be topped with a I-foot bentonite seal and then capped with approximately 6 feet of bentonite/cement grout, culminating approximately 2 feet bgs Each SVE well will be accessed by an 18-in x 18-in steel manway which will be set in a 3-ft x 3-ft concrete pad A gate valve and V-2