Laserfiche WebLink
1 <br /> Underground Tank Removal <br /> lie The Learner Company j <br /> ` 2711 Navy Drive <br />' Stockton,CA. 95706 <br /> _ <br />' Introduction <br /> The purpose of this project was to remove two underground storage tanks (USTs) The UST's <br />' had a capacity of 10,000 gallons and 4,000 gallons The 10,000 gallon UST had been used for the <br /> storage of diesel fuel and the 4,000 gallon UST had been used for the storage of gasoline Site <br /> investigation and sampling was conducted by Brian Pabst of FGL, Inc , under the oversight of <br />' Mchael Kith of the San Joaquin County Environmental Health Division <br />' Field Observations <br /> The two UST's were uncovered with a Caterpillar 235 track excavator After uncovering the <br /> tanks the fill and vent lines were removed from the tanks The USTs were then"triple rinsed" and <br /> the rmsate was removed from the USTs by OCS Recyclers of Fresno The tanks were uaerted <br />' with 30 pounds of dry ice per 1000 gallons to purge all oxygen from the USTs for removal and <br /> disposal The tanks were then removed from the ground with an excavator, and required soil <br /> samples collected <br /> � The UST's upon removal were intact with no evidence of any holes in the tanks The UST's were <br /> i constructed of single wall fiberglass material and were manufitc cared by Owens Corning The <br /> ` UST's at the time of installation were backfilled with pea gravel to protect the integrity of the <br /> fiberglass tank shell At the time of uncovering the fuel tanks there was soil discoloration and <br /> hydrocarbon odors present in the sod which was placed on top of the UST's The soils which were <br />' removed from the top of the tanks were placed west of the former tank location and covered with <br /> visquene In addition to the discolored soil,the pea gravel which was used as the tank backfill was <br /> also placed west of the former tank location with the discolored soil <br /> i <br /> ` In addition to the discolored so-1 m the tank excavation, an organic film was formed when a <br /> _ <br /> ` limited amount of groundwater percolated into the open excavation due to soil and gravel <br />' displacement or removal, and then came mto contact with the remaining contaminated <br /> dimugasohne soil and gravel at the bottom and sidewalls of the excavation causmg <br /> 1 = diesel/gasoline to leach out into the groundwater and stagnate on top of the groundwater inside <br /> the excavation- The petroleum contaminants observed m the pea gravel most likely are from over <br /> fillage of the tanks due to the fact that the UST's were not equipped with over spill contamment at <br />' the fill niers <br /> 1 <br /> 1 t <br /> 1 <br />