SITE INFORMATION AND CORRESPONDENCE FILE 1

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i t Introduction f Brewer Environmental Services (BES) completed a site investigation and initiated remediation of 1 a JP-4 release at a fueling facility near Tokyo, Japan. This paper will focus on the remediation portion of the project. Due to several factors described below, the selected technology of Multiphase Extraction (Bioslurping) was key to a successful initiation of remediation at the site. To the authors knowledge, this was the first application of the technology in the Far East and one of the few times that it has been applied to groundwater depths approaching 15 meters (50 4 ft). Background The site is approximately 40 km (25 miles) inland of the Pacific coastline and is located west- northwest of the Tokyo metropolitan area on the main island of Honshu, Japan. The fuel delivery system onsite consists of fuel storage tanks, pumphouses, underground piping, lateral hydrant control pits, and hardstands. A leaking underground lateral hydrant control pit was considered the source of the subsurface JP-4 contamination encountered beneath this portion of the project site. The site is elevated 125 meters (415 ft) above mean sea level (msl) on a relatively flat upland alluvial plain composed of unconsolidated volcano-clastic sediments originating from the central highlands_ These unconsolidated sediments are composed of sand and gravel with occasional cobbles and discontinuous silt and clay lenses. Most of the sediments are suspected to be saturated with exploitable quantities of groundwater . Groundwater beneath the site consists of a deep production aquifer at about 60 - 85 in (200 280 ft) above msl and a perched aquifer which is at approximately 112 in (367 ft) above msl at the site. This corresponds to a depth of approximately 14 in (46 ft)below ground surface at the site. JP-4 is a jet fuel that is very similar to gasoline and is composed of organic hydrocarbon compounds that fall in the range C6 to C14. These compounds fall into .two classes: the aromatics and the aliphatics which are divided into three families: the alkanes; the alkenes; and the alkynes. Alkanes represent 95% of the vapor and aromatics make up 2% of the vapors (USEPA,1992). JP-4 is no longer used at the project site. :w Three previous investigations of the fuel leak had been conducted at the site prior to the authors `^ involvement. These investigations produced five 50 mm (2") groundwater monitoring wells set at a general depth of 15 meter(49 ft) and a vapor well which extend to a depth of 13 meters (42 ft). The five wells were screened in the interval from I1 to 15 m (36 to 49 ft) while the vapor well was screened from 8 to 13 in (26 to 42.6 ft). During the investigation phase of the project, the authors also installed five additional 50 mm (2")wells to a depth of 15 in (49 ft). These wells had screened minimum intervals of 4.5 in (15 ft). Generally they are screened from a depth of 15 380