Final Report
Delineation of the South Tertiary Lagoon Berm
Winston-Thomas
Feb 1, 1999
PSARA Technologies for CBS Corp.
1.0 INTRODUCTION
This document constitutes the final report for the delineation of the south berm of the tertiary treatment lagoon at the Winston Thomas site in Bloomington, Indiana. The work described in this report was performed in August and November of 1998.
This report includes a descriptive narrative of work performed, along with associated figures and tables. Additional records associated with this project, including laboratory certificates of analysis, chain-of-custody documents, etc., are available for review and future reference at CBS Corporation in Pittsburgh, Pennsylvania.
2.0 BACKGROUND
2.1 GENERAL
The Winston Thomas wastewater treatment plant is owned by the City of Bloomington and was operated from 1933 until 1982, when the plant was closed. From 1958 to 1982, the Westinghouse facility in Bloomington used the sewer system associated with the Winston Thomas facility. During this time period, polychlorinated biphenyls (PCBs) from the manufacture of capacitors at the former Westinghouse facility were occasionally discharged to the treatment plant. Consequently, sludge, water, and waste materials associated with many of the Winston Thomas process units became impacted with PCBs and subject to remediation under a 1985 Consent Decree issued for the site. These units inclucle the sludge digester tanks, sludge drying beds, tertiary lagoon, trickling filter, abandoned lagoon, and sludge piping associated with the digesters and drying beds. Since closing the Winston Thomas facility in 1982, the City of Bloomington has continued the maintenance of the former treatment plant site.
The Winston Thomas facility covers an area of approximately 26 acres. Seventeen acres comprise the tertiary lagoon, which contains 2 to 5 ft of water. The facility is surrounded by a fence to discourage public access. In 1997, four anaerobic digesters, three drying beds, and kludge piping associated with the digesters and drying beds were remediated In 1998, tvo areas at the Winston Thomas facility were remediated under the Consent Decree, including the abandoned lagoon and the trickling filter. In addition, remcdiation activities were initiated at the tertiary lagoon. Remediation of the tertiary lagoon will be completed in 1999. Each of these areas is accessible via a network of gravel roads tied to the mainentrance off West Gordon Pike at the south end of the facility.
The specific area addressed by this report is the south berm of the tertiary lagoon. The tertiary lagoon servedas the final waste water treatment stage prior to cessation of treatment activities at Winston Thomas in1982. Sludge and suspended solids that carried over from the secondary clarifiers settled in the lagoon. The lagoon bottom consists of a 2-ft clay liner that was placed during the construction of the tertiary lagoon in1967. The berm surrounding the tertiary lagoon: is comprised of silty clay
2.2 PREVIOUS SAMPLING ACTIVITIES
In 1996, Westinghouse conducted an extensive sampling effort. The Alternative Evaluation Plan (AEP) that included determining the volume of material to be remediated in the tertiary lagoon area. The AEP sampling program included characterization of the lagoon berm, the sludge present in the lagoon, and the underlying clay.
As part of this sampling initiative, the pond-side of the lagoon berm was characterized for PCB content. Samples were collected for PCB analysis from the north, south, east, and west sides of the berm at three locations. Samples were collected in 6-in. increments at each location for a total of 6 samples on each side of the berm. All PCB results were found to be equal to or less than 1.1 ppm. Composite samples of the lagoon berm were also collected to determine waste characteristics and geotechnical parameters, including permeability, moisture content, particle size distribution, and specific gravity.
The 1996 AEP sampling program also included a PCB delineation study of the abandoned lagoon area. As part of this initiative, samples were collected along the perimeter of the two former lagoons, as defined by the Consent Decree Metes and Bounds, to more accurately refine the lateral delineation of the abandoned lagoon area. Based on this study, PCBs were identified beneath the first 12 ft of the tertiary lagoon berm (grid column M in Figure 1) at 6 locations. The sample results for the grid column M locations are presented in Figure l.
A sludge layer was exposed under the outside toe of the western end of the south berm during remediation of the dry ing bed perimeters. Samples of this sludge layer were found to contain PCBs. This material was not removed at the time so that the integrity of the berm would be maintained while the lagoon contained water.
3.0 SUMMARY OF FIELD ACTIVITIES
All sampling and analysis for this project was conducted in accordance with the approved Field Sampling Plan for the Remediation of the Tertiary Lagoon dated May 5, 1998, and the approved Field Sampling Plan for the Delineation of the South Berm of the Tertiary Lagoon dated October 26, 1998. Direct-push sampling services were provided by Midwest Environmental Drilling under the direction of PSARA Technologies, Inc.
S ur veying
During the AEP assessment activities, a grid system with Northing-Easting coordinates was establishedacross the abandoned lagoon area. Samples were collected at intervals of 50 ft (with some spaced at 25 ft along the north-south and east-west coordinate lines across the area, thereby creating a grid system.
A new by 25-ft grid system was established across the abandoned lagoon area during a subsequentpre-excavation delineation study. This grid system was designed to overlay the pre-existing sample points such that most of the interior sample points from the AEP study (i.e., those locations with identifiers ending in "I") were located in the approximate center of a new 25-ft by 25-ft grid. This grid system was extended over the eastern portion of the south tertiary lagoon berm and then west along the remainder of the south berm. Blue survey flags were used to mark the corners of the grids. Figure 2 shows the layout of this grid system across the south berm.
3.2 SOIL SAMPLING
As described in the Work Plan for the abandoned lagoon, the abandoned lagoon
excavation extended north to a line between grid rows "L" and "M," as shown in Figure 2.
This line roughly corresponds to the toe of the south tertiary lagoon berm. The
abandoned lagoon excavation also extended w est to within approximately 5 ft of the easternmost drying bed perimeter grid, as shown in Figure, 2. PCB soils north or the "L and "M" line and west of the abandoned lagoon excavation area are beneath the berm and were addressed as part of this delineation sampling project.
3.2.1 Delineation Sampling of the Eastern Portion of the South Berm
On June 1 and 2, 1998, soil samples were collected from rows "M" and "N" of the eastern portion of thesouth berm in conjunction with additional pre-excavation sampling in the abandoned lagoon area. Samples were collected at 12-in. depth intervals from the center of each grid or partial grid to the desired depth using direct-push sampling methods. Boring depths for each sample location were extrapolated from elevation and PCB concentration data from the abandoned lagoon delineation studies, as shown in the crosssection in Figure 3.
Samples from each depth interval were placed in 4-oz precleaned glass jars supplied by the analytical laboratory, labeled, and placed on ice for submittal for PCB analysis. Split-spoon samplers were cleanedbetween samples using a tap water and nonphosphate detergent wash, tap water rinse, distilled water rinse, methanol rinse, and a final distilled water rinse.
Filled sample containers were packed in a cooler with ice for transport to Heritage Laboratories, Inc. Each soil sample was submitted for analysis of PCBs using EPA Method 8082. One duplicate sample was submitted and analyzed tor every 10 samples collected. In addition, one field rinseate blank was submitted daily by pouring distilled water through the split-spoon sampler directly into a laboratory clean bottle and the bottle sealed.
A total of twenty 25-ft by 25-ft grids were sampled during this assessment of the south berm. Figure 4 shows a cross sanction of the eastern portion of the south berm along with PCB concentrations exceeding 25 ppm. Table 1 presents the sample numbers, dates, depth intervals for each sample, and analytical results.
3.2.2 Delineation Sampling of the Western Portion of the South Berm
On November 10 through 12, 1998, soil samples were collected from rows "N" and "O" of the western portion of the south berm (see Figure 2). Samples were collected at 12-in. depth intervals from thea pproximate center of each grid or partial grid to the desired depth using direct-push sampling methods. Initially, boring depths for each sample location were extrapolated from elevation and PCB concentration data from the drying bed perimeter and abandoned lagoon delineation studies (see Figure 3). In addition, the borings at locations N3W and NOW were advanced to refusal to determine the depth to the bedrock urface. After the first six borings were completed, the remaining borings were also completed to the top of bedrock. When a grid was found to contain PCBs at concentrations equal to or greater than 25 ppm, any adjacent grids that had not been previously sampled were also sampled until a clean perimeter was determined.
Sample handling and decontamination procedures were performed in the manner described previously.Quality control samples were collected in accordance with the Field Sampling Plan.
A total of nineteen 25-ft by 25-ft grids were sampled during the assessment of the western portion of the south berm. Figure 5 shows a cross section of the western portion of the south berm along with PCB concentrations exceeding 25 ppm. Table 2 presents the sample numbers, dates, depth intervals for each sample, and analytical results.
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