ARCHIVED REPORTS_XR0005010 - Laserfiche WebLink

Home Browse Search

• 1 Dissolved oxygen and ground water depth data collected during the pilot study Indicate that IAS, combined with SVE should provide a viable alternative for remediation of Impacted ground water at the site The ground water depth was Increased (depressed) as much as 144 feet in ASO-1 (located approximately 3 feet from AS-1),groundwater depth decreased as much as 0 20 feet in ASO-2 No significant change In groundwater depth was anticipated In ASO-3 and therefore,groundwater depth was measured only once Dissolved oxygen in ground water was measured in the IAS observation wells at several intervals throughout the IAS test In ASO-1, dissolved oxygen ranged from 84 1% to 87 4%,in ASO-2,dissolved oxygen ranged fit om 16 0%to 32 9%,dissolved oxygen was measured at 62 4% in ASO-3 It appears that the effective radius of Influence for the air sparging wells on-site may be as great as 20 to 30 feet The Increased dissolved oxygen and the change in groundwater depths indicate that the injected air had an Influence on all IAS observations wells at the site Although the concentration of petroleum hydrocarbons Increased in two of the three observation wells,this may be a results of desorption of hydrocarbons from the impacted soil In the smear zone or sample collection techniques REMEDIATION WELL INSTALLATION On 19 April 1997, one additional SVE well, VW-7 was installed at the eastern edge of the site to a depth of 15 feet Also six in-situ air-sparing(IAS)points point were installed using two 21-inch long, 3/8-Inch I D stainless steel screen Implants attached to an anchor tip at 30 feet bsg (IAS-2 through IAS-7)were installed to depths of 30 feet bsg using AGE's van-mounted Geoprobe 5400 soil probing machine Two probe borings were completed as IAS points using one 21-Inch long, 3/8-inch I D stainless steel screen Implant attached at 26 feet bsg to an anchor tip Vinyl tubing (3/8-inch O D ) was extended from the spargmg screen implant to the surface and a filter pack(fine glass beads)was Installed around the sci een Implant from a depth of 25 to 30 feet bsg Bentonite sand(#8 bentonite) was used to make a 4-foot plug above the filter pack and the wells were grouted to surface grade with portland cement An eight-Inch traffic box was installed at the surface for each IAS point On 24 April 1997, monitoring well MW-6 was Installed across Mt Diablo Ave from the site SOIL VAPOR EXTRACTION SYSTEM INSTALLATION On 04 March 1997, a King,BucklHasstech(KBH)(90-032)catalytic oxidation unit(SVE unit)was delivered to the site The extraction equipment was placed inside a fenced enclosure near the west end of the site Replacement parts for all missing or broken items were purchased and installed On 01 April 1997, the natural gas service to the SVE unit on the site was upgraded to 5 pound of pressure per square Inch, the minimum pressure required to operate the KBH catalytic oxidation system The existing netwoi k at the site consisted of subsurface flex piping from wells VE-2,VE-5,VE-6 and Advanced GeoEnvironmental,Inc