Drilling work will consist of installation of approximately 20, two-inch diameter PVC air sparge (AS) wells and 20, four-inch diameter PVC soil vapor extraction (SVE) wells to remediate chlorinated solvents in overburden soil and groundwater beneath the site. Overburden material consists of sand and some gravel/cobbles. Overburden groundwater is located approximately 12.5 to 14 feet below grade. Costs must include Davis-Bacon Act labor rates (prevailing wage). Air Sparge (AS) Wells Approximately 20, two-inch diameter PVC overburden wells installed to 32 feet below grade information and construction as follows: • The wells will be constructed of a 2-foot section of 0.010-inch slot screen and associated riser material to above grade. A two-foot sump is required at the bottom of the well. • Well screen to be backfilled 2-feet above the top of screen with appropriate-sized sand for slot width followed by 3-feet of “choker” sand (finer-grained sand). • Install a 2-foot bentonite seal above the sand pack material and grout to four feet below grade. • A well protector is not required since these wells will be piped underground to the remediation system. An expansion plug or PVC cap is required on top of the well to cover. Soil Vapor Extraction (SVE) Wells Approximately 20, four-inch diameter PVC overburden wells installed to 15 feet below grade.
