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HomeMy WebLinkAbout1991 - Miscellaneous - Geo Engineers - 91030704059103070405 Geo 1! Engineers INTRODUCTION PURPOSE AND SCOPE SITE CONDITIONS SURFACE CONDITIONS AND DRAINAGE SUBSURFACE SOIL CONDITIONS GROUND WATER CONDITIONS FIELD EXPLORATIONS BORINGS . REMEDIAL EXCAVATION MONITOR WELL CONSTRUCTION GROUND WATER SAMPLING PROGRAM GROUND WATER ELEVATIONS CHEMICAL ANALYTICAL PROGRAM SOIL CLASSIFICATION SYSTEM KEY TO BORING LOG SYMBOLS LOGS OF MONITOR WELLS T A B L E O F CONTENTS Page No. 1 1 2 2 3 3 PETROLEUM - RELATED CONTAMINATION 4 GENERAL 4 SOIL CONTAMINATION 5 GROUND WATER CONTAMINATION 6 FREE PETROLEUM PRODUCT 7 SITE REMEDIAL ACTIVITIES 7 CONCLUSIONS 10 Lf7 LIMITATIONS 10 O C List of Figures Figure No. O 0 VICINITY MAP 1 SITE PLAN 2 CT) SITE PLAN AND GROUND WATER ELEVATIONS 3 SOIL SAMPLE LOCATIONS 4 APPENDIX A List of Appendix A Figures Page No. A -1 A -1 A -3 A -3 A -4 A -4 A -4 Figure No. A -1 A -2 A -3 & A -4 CTS 1NUV { JAN 3 1 1992 I C► s r s► 1 UYWjIj !AMII,N,G....DEPT.;. Geo Engineers REPORT ASSESSMENT AND REMEDIATION OF SUBSURFACE PETROLEUM- RELATED CONTAMINATION FORMER TIME-DC TRUCK TERMINAL FOR BEDFORD PROPERTIES INTRODUCTION This report presents the results of our services during the assessment and remediation of subsurface petroleum- related contamination at the site of the former Time -DC Truck Terminal in Tukwila, Washington. The former truck terminal facility is located south of the Duwamish River and north of the intersection between 48th Avenue South and Interurban Avenue South. The Lf7 site location and surrounding features are shown in Figure 1. The general ti layout of the site is shown on Figure 2. O CD O The former truck terminal facility included 15 underground steel tanks used for the storage of diesel, gasoline, lubricating oil and waste oil. These tanks included ten 20,000 - gallon diesel tanks, two 10,000 - gallon diesel tanks, one 10,000 gallon gasoline tank, one 10,000 gallon lube oil tank and a 5,000 gallon waste oil tank. The underground tanks were removed from the site during February 1989. The locations of the former tanks are shown in Figure 2. Soil contaminated by petroleum products and free (floating) product consisting of diesel fuel were encountered during removal of the underground storage tanks. PURPOSE AND SCOPE The purpose of our services was to monitor the tank removal activities, explore and evaluate the extent of subsurface petroleum - related Geo Engineers contamination, develop recommendations for remedial measures and monitor the remedial activities at the site. The scope of services completed during this project includes:. 1. Monitor the removal of the fifteen underground storage tanks. 2. Subcontract and monitor the drilling of eight exploratory borings and the installation of monitor wells in each boring. 3. Develop recommendations for remedial actions and monitor the remedial program. 4. Collect soil and ground water samples from each boring /monitor well and from the excavation completed for removal of the tanks and contaminated soil. 5. Subcontract the analysis of the soil and ground water samples for god - O the presence of petroleum related contamination. O CD O SITE CONDITIONS 0, SURFACE CONDITIONS AND DRAINAGE The general layout of the former Time -DC truck facility is shown in Figure 2. The facility included a corrugated metal building, fifteen underground storage tanks and three fuel pump islands prior to the remedial activities. The underground storage tanks and fuel pump islands were removed from the site as part of the remedial program. The western portion of the corrugated metal building included remote fueling lines and truck maintenance facilities. The western portion of the building was demolished and removed from the site during the remedial program. The site is bordered by the Duwamish River along the eastern property line. The surface of the site is relatively level and is covered by asphaltic concrete pavement outside of the limits of the remedial 2 Geo ,, excavations and building footprint. Runoff from precipitation is collected in a storm drain system and is pumped to the Duwamish River. Runoff from areas where remedial activities were conducted was diverted to a Metro sewer line. SUBSURFACE. SOIL CONDITIONS Information pertaining to subsurface soil conditions was obtained by drilling eight borings (MW -1, MW -2 and MW -4 through MW -9) at the locations indicated in Figure 3 and observing conditions in the excavation completed for the removal of the underground storage tanks and petroleum- contaminated soil. Details of the field exploration program and the boring logs for MW -8 and MW -9 are presented in Appendix A of this report. The logs for MW -1, L.f7 O MW -2 and MW -4 through MW -7 are given in our reports dated April 18, 1989 Q and May 23, 1989. Boring MW -3 was completed by Geraghty & Miller, Inc. O C;) Two general soil units were observed in the remedial excavation and O) borings at the site. The uppermost soil unit consists of 8 to 10 feet of brown to gray interbedded silt, silty sand and sand. The lowermost unit consists of black fine to medium sand. The base of the black sand was not encountered in the excavation or the borings. Numerous horizontal tree logs, ranging from 1 to 4 feet in diameter and up to 100 feet in length, were encountered in the lower soil unit. GROUND WATER CONDITIONS Ground water conditions at the site were explored by constructing wells (MW -1, MW -2 and MW -4 through MW -9) in each of the borings completed by GeoEngineers. Construction details for MW -1, MW -2 and MW -4 through MW -7 are given in our reports dated April 18, 1989 and May 23, 1989. Construction 3 1; Ln PETROLEUM- RELATED CONTAMINATION CD O GENERAL CD Subsurface petroleum- contaminated soil was detected during the removal © of the fifteen underground storage tanks from the site. The tanks were Geo 1 =elm- 1 ! Engineers details for MW -8 and MW -9 are given in Appendix A of this report. Well MW -3, installed by Geraghty & Miller, Inc., was included in our field measurements to provide additional information pertaining to ground water conditions beneath the site. Ground water was encountered at depths of approximately 11 to 14 feet below the ground surface. Water level measurements conducted on June 12, 1989 indicate that the shallow ground water beneath the site generally flows northeastward toward the Duwamish River. Water table elevations at each well on June 12, 1989 are shown in Figure 3. Water table contours based on interpretation of the June 12, 1989 measurements are also shown in Figure 3. removed between February 15 and February 22, 1989 by Gaston Brothers Excavating. Free (floating) petroleum product was detected on the water table in portions of the excavation completed for removal of the tanks. The extent of subsurface contamination at the site by petroleum products was evaluated by: 1. Physical examination of soil samples for visual indications of petroleum contamination. 2. Conducting field sheen tests on the soil samples. 3. Sampling the well casings for presence of free (floating) petroleum products. 4 Geoff Engineers 4. Analyzing soil and ground water samples from the remedial excavation and the borings /wells for the presence of petroleum - related contamination. The laboratory data are presented in Appendices B, C and D. SOIL CONTAMINATION Soil samples were collected from beneath the tanks during the tank removal program and analyzed for the presence of total petroleum hydrocarbons (TPH) and benzene, ethylbenzene, toluene and xylenes (BETX). The concentrations of TPH and BETX detected in the soil samples collected during the tank removal program generally exceeded Ecology's cleanup guidelines for underground petroleum storage tanks. The analytical results Ln "at for soil samples collected during the tank removal program are summarized 0 in Table 1. O CZD The extent of the petroleum- contaminated soil was evaluated primarily 0) during the excavation phase of the remedial program. The remedial program is described in a later section of this report. Soil samples were collected from the base and sidewalls of the excavation and submitted for analysis of the presence of TPH and BETX. The locations from which soil samples were collected from the excavation are shown in Figure 4. The analytical results for soil samples from the excavation are summarized in Table 2. Excavation of soil continued until the concentration of petroleum - related contaminants in the remaining soil were less than Ecology's cleanup guidelines. The limits of the excavation are shown in Figures 2, 3 and 4. Soil samples were also collected from MW -1 through MW -9 and submitted for analysis of the presence of TPH, BETX and /or fuel hydrocarbons. The analytical results for soil samples from the borings are summarized in 5 Geor Engineers Table 3. Petroleum- related contaminants were not detected in the soil samples from MW -1, MW -2, MW -3 and MW -5 through MW -9. TPH was detected at a concentration of 6.3 ppm in the soil sample from MW -4. BETX and fuel hydrocarbons were not detected in the soil sample from MW -4. GROUND WATER CONTAMINATION Ground water samples were collected from MW -1 through MW -9 and submitted for analysis of TPH and BETX. The analytical results for the ground water samples from the wells are summarized in Table 4. Petroleum - related contaminants were not detected or were detected at concentrations much less than drinking water quality standards in the ground water samples from MW -1 through MW -9. O Ground water samples were also collected from the remedial excavation and from a temporary recovery well that was installed in the remedial ti excavation. The analytical results for the ground water samples from the excavation and recovery well are summarized in Table 5. Petroleum- related O) contaminants were detected at concentrations greater than drinking water quality standards in the ground water samples collected from the excavation during the initial portion of the remedial program. Petroleum- contaminated soil and free product were present in the excavation during the initial portion of the remedial program. Petroleum- contaminated soil and free product were removed from the excavation as part of the remedial. program. Petroleum - related contaminants were generally not detected, or were detected at concentrations less than drinking water quality standards, in the ground water samples collected from the excavation during the later portion and after completion of the remedial excavation. 6 Geo!Engineers FREE PETROLEUM PRODUCT Free (floating) product was encountered during removal of the underground storage tanks. Analysis of petroleum product present in the excavation indicated that the product was diesel fuel. SITE REMEDIAL ACTIVITIES Gaston Brothers Excavating excavated approximately 14,500 cubic yards of soil contaminated by petroleum products between February 15 and May 26, 1989. The limits of the excavation are shown in Figure 4. The excavated soil was stockpiled on -site. Free product and contaminated soil were found to extend horizontally beneath the western portion of the terminal building. A portion of the of Lr7 O the building was demolished during March 1989 to remove the contaminated ( CD soil and-free product beneath the building. O As described above, soil samples were collected from the base and sidewalls of the excavation and submitted for analysis of the presence of TPH and BETX. Excavation of soil continued until the concentration of petroleum - related contaminants in the remaining soil were less than Ecology's cleanup guidelines. Ecology's petroleum cleanup guidelines at the time of the site remedial work are summarized below. PARAMETER CONCENTRATION Benzene 660 ppb Toluene 143 ppm Ethylbenzene 14 ppm Total Petroleum Hydrocarbons 200 ppm Free product that was encountered in the excavation was recovered with the use of a product recovery well and by skimming product from the water 7 Geoff Engineers surface with vacuum trucks operated by Environmental Transport, Inc. and Northwest EnviroService, Inc. The majority of the free product was recovered by skimming the surface of the water in the excavation with a boom and removing it with the vacuum trucks. Water and product that was removed from the excavation with the vacuum trucks was transported to ChemPro's facility for disposal. Water that was pumped from the recovery well was discharged to a Metro sewer line (Minor Discharger Permit No. 154). Contaminated soil that was removed from the excavation was subjected to a thermal treatment process by Olympus Environmental, Inc. The soil was treated between July 5, 1989 and October 5, 1989. The thermal treatment process involved the removal of petroleum hydrocarbons from the soil by the Lf7 application of heat followed by treatment of the exhaust gases. The d' treatment plant consisted of a diesel -fired rotary kiln with facilities to N— Cr) control air emissions. Soil was conveyed to the kiln where the petroleum O U 7 hydrocarbons were volatilized and partially incinerated. The exhaust gas treatment plant included a bag house and wet scrubber to reduce the emission of dust and volatile hydrocarbons. Olympus Environmental monitored the effectiveness of the thermal treatment process by collecting soil samples at a frequency of about one sample per 240 cubic yards of treated soil. These soil samples were analyzed to determine the concentration of TPH remaining in the soil after treatment. The analytical results are given in Appendix D and summarized in Table 6. The concentrations of TPH detected in the treated soil averaged less than 50 ppm and did not exceed 100 ppm. Ecology's - current cleanup guideline for TPH is established at 200 ppm. 8 Geo Engineers GeoEngineers also collected samples of the treated soil to monitor the effectiveness of the treatment process. Samples were collected by GeoEngineers at a frequency of about one sample per 1,850 cubic yards of treated soil. These soil samples were analyzed to determine the concentrations of TPH, BETX and fuel hydrocarbons remaining in the soil after treatment. The analytical results are given in Appendix D and summarized in Table 7. The analytical results for the samples collected by GeoEngineers were generally similar to the results obtained by Olympus Environmental and indicated that the concentration of petroleum- related contaminants remaining in the treated soil were less than EFECTogy's cleanup Lf7 guidelines. Comparison of the concentrations of TPH before and after O 0 treatment indicates that the thermal treatment process removed about 98 ti percent of the petroleum product from the soil. 0 The remedial excavation was backfilled with crushed concrete from the base of the excavation to about one foot above the water table. The crushed concrete was obtained from a recycling plant. The remaining portion of the excavation was backfilled with treated soil. A layer of woven geotextile fabric was placed over the crushed concrete prior to placement of the treated soil. Approximately 1,000 cubic yards of oversized material (cobbles, concrete and wood) were removed from the soil prior to treatment. The oversized material was transported to the Newcastle Landfill for disposal. An additional 400 cubic yards of soil that was not subjected to the thermal treatment process was transported to the Ceder Hills Landfill for disposal. Permission for disposal of the untreated soil and oversized material was granted by the King County Health Department prior to disposal. 9 • Geo ! Engineers CONCLUSIONS Based on the results of our field observations and analytical testing, it is our opinion that actions to mitigate subsurface petroleum- related contamination in the vicinity of the former underground storage tanks at the Time -DC facility have been completed successfully. On -site observations and chemical analysis of soil and ground water samples indicate that no petroleum- related contamination of regulatory significance remains in the vicinity of the former underground storage tanks. LIMITATIONS We have prepared this report for use by Bedford Properties. This report may be made available to regulatory agencies. This is not L!D intended for use by others and the information contained herein is not O applicable to other sites. M Our interpretation of soil conditions during remediation is based on O7 field observations and chemical analytical data. It is always possible that areas with undetected contamination may exist in portions of the site which were not excavated or analyzed. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in this area at the time the report was prepared. No other conditions, express or implied, should be understood. 0 0 0 1.0 Geo �j Engineers Please call if you have any questions regarding this submittal. Yours very truly, GeoEngineers, Inc. JHB:JAM:sd Two copies submitted John H. Biggane Associate James A. Miller, P.E. Principal 11 Former Building L . GATEWAY DRIVE 10.000 - Gallon Lube Oil Tank (Removed) 14 EXPLANATI 1 1 2 3 4 5 5,000 - Galion Waste Oil Tank (Removed) Ten 20,000 - Galion Diesel Tanks (Removed) \u 1 10 1 9 f 8 T 1. d 0 c 0 V FORMER UNDERGROUND STORAGE TANK LOCATIONS Fuel Islands (Removed) 1 11 1 12 1 Two 10.000 -Gallon Diesel Tanks 13 Existing Building Property Une 0 10.000 - Gallon Gasoline Tank (Removed) Limit of Excavation Geo Engineers 9103070405 SCALE IN FEET 40 . 80 SITE PLAN FIGURE 2 N J i Former Building B¢ •6 . EXPLANATION: • MW-3 �? \!84.35 Geo eP Eng MW-2 84 .12 MIN-5 MW 6 83.85 83.65 MW -4 8 4.10 MW -7 \ 83.66 Approximate Limits Of Excavation 0 MW -8 84.69 MONITOR WELL LOCATION AND NUMBER MW -1 84.35 WATER TABLE ELEVATION ON 6/12/89 o Existing Building 150 300 - 1 - - -� SCALE IN FEET GROUND WATER CONTOUR BASED ON 6/12/89 MEASUREMENTS GENERAL DIRECTION OF GROUND WATER FLOW BENCHMARK AT WATER MAIN LID. ASSUMED ELEVATION AT 100.00 FEET. FIGURE 3 SITE PLAN AND GROUND WATER ELEVATIONS 1