Final Report

Completion of the removal action for the Abandoned Lagoon Area

Winston-Thomas Waste Water Treatment Plant
April 22, 1999
PSARA Technologies for CBS Corp.

This report includes a descriptive narrative work performed, along with associeated figures, tables, and photographs. Additonal records associted with this project, including air monitoring results, weekly progress reports, laboratory certificates of analysis , chain-of-custody documents, etc, are available for review and furture reference at CBS Corporation in Pittsburgh, Pennsylvania.
The abandoned lagoon covered an area of approximately 2 acres within the fenced area of the Winston Thomas facility. The abandoned lagoon area sloped gently from east to west and was bounded to the east by a partially exposed 39-in.-diameter sanitary sewer, to the north by the tertiary lagoon berm, to the west by former sludge drying beds 1 and 2, and to the south by a small, intermittently flowing creek. Figure 2 shows the location of the abandoned lagoon area at the Winston Thomas facility.

2.3 PREVIOUS SAMPLING ACTIVITIES
In 1996, Westinghouse conducted an extensive sampling effort [the Alternative Evaluahon Plan (AEP)] at the Winston Thomas site, which included the delineation of the lateral and vertical extent of PCBs in the abandoned lagoon area. Figure 3 presents the sampling locations and data obtained from the abandoned lagoon study. The AEP study of the abandoned lagoon involved two distinct sampling initiatives. The first initiative involved sampling along the perimeter of the two former lagoons, as those perimeters were defined in the Consent Decree documents. Wherever these perimeter samples identified PCBs in excess of 25 ppm, the perimeter was moved outward approximately 25 ft, and a new sampling location was established. In this way, a more accurate lateral delineation of the area was accomplished.

Based on this sampling, the perimeter of the abandoned lagoon was defined to the west by the sludge drying beds (previously remediated and sampled), to the north by the berm of the tertiary lagoon, to the east by a 39-in. sanitary sewer pipe, and to the south by an active creek. Although the 1996 AEP study identified PCBs beneath the tertiary lagoon berm (grid column M in Figure 3), the abandoned lagoon project was bounded to the north by the toe of the berm to avoid impairing the stability of the tertiary lagoon. Remediation of the abandoned lagoon occurred prior to removal of all the water from the tertiary lagoon.

The second sampling initiative associated with the AEP study involved grid-based sampling throughout the interior of the area. Samples were located on a 50-ft by 50-ft grid covering an area of approximately 77,500 sq ft (1.78 acres).

3.0 SUMMARY OF REMEDIATION ACTIVITIES

A Work Plan, dated May 5, 1998, was prepared to address remediation of PCB soils in the abandonedlagoon area. This plan was approved by the Consent Decree parties prior to the start of excavationactivities at the site. Health and safety, air monitoring, post-excavation verification sampling, andtransportation and disposal were conducted in accordance with the approved Work Plan.

All remediation activities were performed by OHM Remediation Services Corp. (OHM) under thedirection of CBS and in cooperation with the site owner, the City of Bloomington. Project photographsshowing remediation and sampling activities are presented in Appendix A.

3.1 SITE PREPARATION

3.1.1 General

Prior to beginning remediation activities, support facilities were arranged for the site. Support facilities included an office trailer; water, electric, and phone services; a support trailer for personnel decontamination and storage; and sanitary facilities to accommodate all of the workers and site visitors.In addition, a portable truck scale was installed along the haul road located south of former sludge drying bed #2 to weigh outgoing loads of material.

3.1.2 Facility Access Roads

Existing service roads north and east of former sludge drying bed #2 were improved with a 12 in. layer ofcrushed stone borrowed from the clean processed stone stockpile generated from the trickling filter remediation project. The stone was placed on a 4-oz non-woven geotextile liner. These improvements were made to facilitate a loop traffic pattern for trucks.

3.1.3 Intermittent Creek Diversion

The intermittent creek was temporarily diverted to facilitate excavation of grids along the north side of theditch. This diversion ditch was excavated approximately 10 to 15 ft south of the intermittent creek from the aboveground storm sewer to the haul road at the southeast corner of former sludge drying bed #2. The diversion ditch was stabilized using compaction measures, crushed stone, straw bales, and silt fencing toprevent erosion.

3.1.4 Decontamination Pad

A decontamination pad was constructed along the haul road on the west side of the Winston Thomasfacility to provide a location where equipment and trucks could be spray washed. The pad consisted of alarge, portable, pre-fabricated metal pan. Rinseate water was collected in a central sump and later pumpedto an onsite holding tank for treatment and disposal.

3.1.5 Water Collection and Treatment

A temporary onsite wastewater treatment system was constructed south of the abandoned lagoon area to handle wastewater from decontamination operations, spring water containment, and storm water runoff. The system, which had a design capacity of 50 8pm, included two 12,000-gal holding pools for contaminatedwater, a 50,000-gal holding pool for treated water, process submersible pumps, a sand filter, an in-line bag filter, a carbon adsorption unit, and associated piping, hoses, and valves.

3.2 SURVEYING

During the AEP assessment activities, a grid system with Northing-Easting coordinates was established across 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 25-ft by 25-ft grid system was established across the abandoned lagoon area during the pre-excavation delineation study described previously. This grid system was designed to overlay the pre-existing sample points such that most of the interior sample points from the ALP 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 as presented in Figure 3. Each grid was identified using analpha-numeric designation, with grids "A" to "M" along the northsouth coordinate axis and grids "1" to "13"along the east-west axis. This system was used as the basis for identifying pre- and post-excavation samplelocations and excavation areas.

Prior to excavation, the relative elevations of the corners and center of each grid were also determined. Elevations were measured relative to an established benchmark located on the southwest corner of a concrete inlet, which was located in the southwest corner of the tertiary lagoon.

3.3 REMEDIATION OF THE ABANDONED LAGOON

The contaminated soil in the abandoned lagoon was removed using standard excavation equipment. The excavation was performed by removing soils to at least the depth determined by the pre-excavation sampling effort. Material was removed from each grid using a track excavator, loaded into an off-roaddump truck, and transported to a soil stockpile/material loading area. This process continued until at leastone day's supply (approximately 300 cu yd) of soil was accumulated in the stockpile. The stockpile waslocated within the exclusion zone but adjacent to the haul road. The material from the stockpile was thenloaded into lined transport trucks using a second track excavator stationed within the material loading area.The visqueen liners were draped over the sides of the truck. Prior to exiting the site, the filled trailers werethen covered with tarps, weighed, decontaminated (tires and rails), and placarded.

Excavation activities were conducted between July 16 and August 20, 1998. Grids D1, E1, F1, and G1 were excavated on July 16, 1998. The removal of these grids was time-critical due to the plan to install ahaul road through a portion of Row 1, which was located on the east side of former sludge drying bed #2(see Section 3.1). In addition, grid B4 was excavated on this date in order to construct a diversion ditchapproximately 10 to 15 ft south of the intermittent creek. After this excavated grid was verified clean, thecreek was diverted into this temporary channel.

In general, excavation of the abandoned lagoon began along the north and east sides of the area andproceeded to the southwest as grids were confirmed clean. However, following removal of grids D6, D7,and D8, visual and olfactory evidence of residual sludge was observed in the sidewalls of several adjacent grids. All visual sludge was subsequently removed from 19 full or partial grids as directed in the field by the onsite government agencyrepresentatives.

A total of 124 full or partial grids were excavated within the abandoned lagoon area. All material was removed and disposed of at a Toxic Substances Control Act (TSCA)permitted landfill in Belleville, Michigan, operated by the Environmental Quality Co. A total of 455 truck loads containing approximately 11,000 tons (about 7,100 cu yd) of excavated material were transported to the landfill for disposal. Figure 6 shows the final excavation depth and final relative elevation for each grid.

3.4 WATER TREATMENT

Wastewater from decontamination operations, spring water containment, and storm water runoff weretreated in the onsite treatment system. The system was operated in a batch treatment mode consisting of9,000- to 10,000-gal batches. Approximately 95,800 gal of wastewater was treated and discharged to the City sewer system with approval from City of Bloomington officials. Effluent samples were collected and analyzed in accordance with the Field Sampling Plan and the City of Bloomington Utilities Industrial Pretreatment Permit, which had a discharge limit of 0.01 mg/L PCBs, prior to discharge (see Section 4.2).Upon completion of water treatment activities, the spent sand filter, bag filter, and carbon filter media and residue were disposed of as TSCA wastes along with the excavated soils at the Environmental Quality Co.landfill in Belleville, Michigan; the exact quantities of the materials disposed are not known.

Due to the high volume of spring water that accumulated in several excavated grids near the southwest corner of the abandoned lagoon area, the untreated water in the grids was pumped directly to the tertiarylagoon with permission of City of Bloomington officials. This was done so that the untreated water wouldnot spill into the diverted creek to the south. These activities occurred during the week of August 3, 1998.

3.5 RESTORA TION

All deeper excavation areas were partially backfilled with clean material from adjoining grids and roughgraded to promote positive drainage towards the intermittent creek. In accordance with the SOW, aminimum of 12 in. of clean cover was placed over the area and fine graded. The cover material included a minimum of 9 in. of clean fill and 3 in. of topsoil.Laboratory analysis identified no PCBs in the clay backfill or topsoil material used at the site. Thedisturbed areas were hydroseeded with a fast growing native grass after topsoil placement, grading, andcompaction. Following completion of all excavation activities, the temporary diversion ditch was backfilled,and the intermittent creek was reopened and allowed to flow along its original channel.

As required by the Work Plan, a spring water collection system was installed following completion of remedial activities. Figure 7 presents an as-built drawing of the interceptor pipe and trench that were installed. 4.0 SUMMARY OF SAMPLING ACTIVITIES

All sampling activities were conducted by PSARA Technologies, Inc., in accordance with the approved Field Sampling Plan.

POST-EXCAVATION VERIFICATION SAMPLING

Post-excavation verification sampling was performed consistent with the procedures described in theapproved Field Sampling Plan. After all of the soil had been removed to the prescribed depth, each grid was visually subdivided into four smaller 12.5-ft by 12.5-ft subgrids. A sample was collected from the 0- to12-in. depth interval in the approximate center of each subgrid and homogenized. Equal portions from each of the four subgrid samples were composited to create a representative grid sample. These composite samples were analyzed for PCBs. If the laboratory result from a grid sample showed a PCB concentrationin excess of 25 ppm, an additional 6-in. lift of soil was removed and the grid was resampled. This procedure continued until all of the delineated grids showed a PCB concentration of less than 25 ppm. Figure 7 presents the final post-excavation verification sample results for the abandoned lagoon. Table 2presents the sample numbers, dates, depth intervals for each sample, and analytical results.

The calculated average remaining PCB concentration for all grids after excavation activities were completed was 5.2 ppm, which is below the final average cleanup criterion of 15 ppm. The arithmeticaverage was determined by totaling the final post-excavation PCB concentrations from all of the excavation grids and dividing this sum by 124 (the number of grids). For grids that had final analytical results reported as "BDL" (below the detection limit of 1.0 ppm), a PCB concentration of 0.5 ppm, or one-half the detection limit, was used in calculating the arithmetic average. In addition, the cleanup criterion of<25 ppm PCBs for each individual grid was also met.

4.2 SAMPLING

Accumulated wastewater from decontamination operations, spring water containment, and storm waterrunoff was treated in a temporary onsite wastewater treatment system operated by OHM. Effluent samples were collected from the 50,000-gal holding tank on four occasions and analyzed for PCBs in accordance with the Field Sampling Plan and the City of Bloomington Utilities Industrial Pretreatment Permit prior to discharge. Table 3 presents the laboratory analytical results. All effluent samples were below the discharge limit of 0.01 mg/L PCBs.

The intermittent creek on the south border of the abandoned lagoon was sampled for PCBs on October 27, 1998, and again on March 5,1999. Samples were collected from the spring diversion pipe using a new pipette. The October water sample was found to contain PCBs at a concentration of 0.46 MEL. The March water sample contained PCBs at a concentration of 0.23 ug/L. Quarterly sampling will continue for one year; the next sampling event is planned for June 1999.

5.0 PERIMETER AIR MONITORING

Perimeter air sampling was performed to ensure that excavation and materials handling operations did notresult in excessive airborne PCB emissions from the site. Air samples were collected using modified polyurethane foam (PUF) samplers in accordance with USEPA Method T-04 and the site-specific Air Monitoring Plan (AMP) dated May 5, 1998. Air samples were analyzed to determine the concentrations of PCBs at the boundaries of the Winston Thomas site during abandoned lagoon remediation operations.Perimeter air monitoring was conducted by PSARA.

Air monitoring stations were located at four locations along the north, south, east, and west perimeters ofthe site as described in the AMP. Sampling was conducted only on days when material handling or excavation took place. One sample representing the prevailing down-wind direction was selected each day for analysis at an offsite laboratory. A meteorological station was installed and operated at the site in orderto determine prevailing wind direction and weather information.

The action level for perimeter airborne PCB concentrations was 1,000 ng/m3 for this site. Table 4 presents the perimeter air sample results for the site during remediation activities. The highest perimeter air sample result showed PCBs at a concentration of 787.8 ng/m3 during remediation of the abandoned lagoon.