Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPSolvent Dike. The Solvent Dike is located approximately 300 feet east of the Process Building. Itwas an unlined basin excavated in the sand and gravel layer. It measured 30 feet by 30 feet. TheSolvent Dike received rainwater runoff from the Solvent Storage Terrace, which housed an acidstorage tank and three storage tanks containing a mixture of used n-dodecane and tributylphosphate. In 1987 the sediment was removed and the area was backfilled, but the Solvent Dikestill contains radiologically contaminated soil.Maintenance Shop Leach Field. The Maintenance Shop Leach Field is located directly northeastof where the Maintenance Shop stood. It consists of three septic tanks, a distribution box, a tiledrain field, and associated piping. It occupies an area of approximately 1500 square feet. Theleach field was used until 1988; all three tanks are now out of service and filled with sand.Because it is located within the area of the North Plateau Groundwater Plume, low levels ofcontamination may be present.Groundwater Recovery System. The Groundwater Recovery System is located in the northwestcorner of WMA 2. It was installed in 1995. The groundwater recovery system includes 3 wellsalthough most of the time water is pumped from two recovery wells at the western lobe of theNorth Plateau Groundwater Plume. Groundwater is pumped from the wells to the LLW2 Buildingfor treatment by ion exchange to remove Sr-90 contaminants. Like all discharge from the LLW2Building, the treated groundwater is pumped to Lagoon 4 or Lagoon 5, then to Lagoon 3, and,eventually, discharged into Erdman Brook through the permitted outfall.Pilot Scale Permeable Treatment Wall. The Pilot Scale Permeable Treatment Wall is locatednorthwest of Lagoon 5. It was installed in 1999. This treatment wall is approximately 30 feetwide, seven feet thick, and 25 feet deep, extending into the Lavery Till. It is filled withclinoptilolite, a natural zeolite material, and covered with soil. Its purpose was to evaluate theeffectiveness of such systems in treating groundwater contaminated with Sr-90.O2 Building. The O2 Building was located southwest of the Low Level Wastewater Building. Itwas a two-story, steel-framed concrete block structure, measuring 27 feet wide, 39 feet long, and30 feet high. It contained a 16 feet deep stainless steel-lined sump. The O2 Building once housedfilters, ion exchangers and other equipment used by NFS and the WVDP to treat low-levelwastewater before transfer to Lagoon 3. The O2 Building was built in 1971 and operated untilRev. 1 B-4