ARCHIVED REPORTS XR0009534 - Laserfiche WebLink

Home Browse Search

' Report-Pilot Remedial System Test Page 21 Former Manna Pro Site l Project No 207 3 ie July 31,2000 r7.0 SUMMARY OF PILOT TEST RESULTS ' 7.1 Discussion of New Soil Analytical Data The soil analytical data as shown in Summary Table l suggests that gasoline impacted soil extends from near the groundwater surface at about 25 feet to depths of more than 50 ' feet bgs The bulk of the contaminant mass lies between about 35 and 45 feet The new data is in general agreement with soil data obtained in prior sampling events at the site A more detailed discussion of the soil data will be forthcoming in the Feasibility Study ' Report 7.2 Discussion of Soil Vapor Extraction Field Work The ICE equipment was in operation for about 82 hours over the course of 10 calendar days The equipment was not operated between May 25 and May 29 as discussed above ' At the time of the pilot test, the groundwater elevation was about 10 feet above the highest level of the most intensely impacted soil which hindered the vapor extraction system Only a relatively low level vacuum could be applied to the system (30-35 inches ' of water) as only approximately 5 feet of screen was exposed above the groundwater table Similarly, the abnormally high water table required that a large head of water be displaced in the air sparge well (20-25 feet) to initiate sparging This required 0 61 to I0 76 atmospheres of pressure (9 to 11 psig) to displace the standing water column, not including additional formation resistance Gasoline Extraction Rates The laboratory test data of the 3 air samples show that the gasoline range hydrocarbons in ' the air samples had a maximum concentration of 16 mg/1 The other two samples contained TPH-G concentrations of gasoline of 1 0 and 1 4 mg/l Data Table 3 calculates the removal of contaminants at various extraction rates Note that for the purpose of estimating removal rates, the air samples were used as follows • The initial air sample was used to calculate soil vapor contaminant mass for the first three days of system operation • The second air sample was used to estimate air stream concentration up until the start up of the air sparge system ' • The final air sample analysis was used to estimate contaminant concentration for the operation of the system after the start of air sparging ' 2937 Veneman Ave , #8240 Geo-Phase Environmental Inc Phone(209)569-0293 Modesto, CA 95356 Fax(209)569-0295 1