REVISED FINAL · 2020. 12. 27. · REVISED FINAL FOCUSED FEASIBILITY STUDY HELEVA LANDFILL SITE LEHIGH COUNTY. PENNSYLVANIA I I EPA WORK ASSIGNMENT NUMBER 37-05-3L59.0 CONTRACT NUMBER

I[* COORATOSJ

INILJLj X GANNETT FLEMING, INC.BALTIMORE, MARYLAND

REVISED FINALFOCUSED FEASIBILITY STUDY

| I VOLUME 1

I I HELEVA LANDFILL SITEr H LEHIGH COUNTY, PENNSYLVANIA

EPA WORK ASSIGNMENTNUMBER 37-05-3L59.0

CONTRACT NUMBER 68-W8-0037

NUS PROJECT NUMBER 0222

MARCH 1991

REVISED FINAL

FOCUSED FEASIBILITY STUDY

HELEVA LANDFILL SITE

LEHIGH COUNTY. PENNSYLVANIA

II EPA WORK ASSIGNMENT NUMBER 37-05-3L59.0

CONTRACT NUMBER 68-W8-0037

NUS PROJECT NUMBER 0222

MARCH 1991

Prepared By: Approved By:

W. Winslow Westervelt, P.E. eonard C.Acting Project Manager ARCS III Program ManagerGannett Fleming, Inc. NUS Corporation

flR303598

I§ TABLE OF CONTENTS.d.

Section Page

EXECUTIVE SUMMARY.............................................. ES-1

1.0 INTRODUCTION...........................................;.. 1-1

1.1 PURPOSE OF REPORT............................... 1-11.2 ORGANIZATION OF REPORT.......................... 1-21.3 BACKGROUND INFORMATION.......................... 1-41.3.1 Site Location and Description................... 1-41.3.2 Site History.................................... 1-41.3.3 Nature and Extent of Contamination.............. 1-81.3.4" Contaminant Fate and Transport.................. 1-101.3.5 Soil Cleanup Levels............................. 1-111.3.6 Environmental Assessment........................ 1-11

2.0 IDENTIFICATION AND SCREENING OF TECHNOLOGIES.............. 2-1

2.1 INTRODUCTION.................................... 2-12.2 REMEDIAL ACTION OBJECTIVES ...................... 2-12.2.1 Applicable or Relevant and Appropriate

Requirements (ARARs)............................ 2-12.2.1.1 Contaminant-Specific ARARs and TBC Criteria..... 2-42.2.1.2 Location-Specific ARARs......................... 2-72.2.1.3 Action-Specific ARARs........................... 2-82.2.2 Remedial Action Levels.......................... 2-122.2.3 Remedial Action Objective....................... 2-182.3 GENERAL RESPONSE ACTIONS........................ 2-202.3.1 Description of Major Contaminated Media......... 2-202.4 IDENTIFICATION AND SCREENING OF TECHNOLOGIES

AND PROCESS OPTIONS ............................. 2-302.4.1 No Action....................................... 2-382.4.2 Institutional Actions........................... 2-392.4.3 Containment..................................... 2-402.4.4 Treatment....................................... 2-452.4.4.1 Thermal Treatment............................... 2-452.4.4.2 Vapor Recovery Treatment........................ 2-492.4.4.3 Fluid Extraction Treatment...................... 2-562.4.4.4 Biological Treatment............................ 2-582.4.4.5 Soil Dewatering and Treatment................... 2-602.4.5 Summary of Screening of Technologies and Process

Options......................................... 2-62

3.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES................. 3-1

3.1 DEVELOPMENT OF ALTERNATIVES..................... 3-13.2 SCREENING OF ALTERNATIVES....................... 3-3

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TABLE OF CONTENTS (cont'd.)

Section Page

4.0 DETAILED ANALYSIS OF ALTERNATIVES......................... 4-1

4.1 INTRODUCTION.................................... 4-14.2 ALTERNATIVE ANALYSIS............................ 4-44.2.1 Alternative 1: No Action....................... 4-44.2.2 Alternative 2: Containment--Extension of

Existing Cap.... ................................. 4-54.2.3 Alternative 3r Limited Treatment of

Unsaturated Soil--34 ug/kg TCE Action LevelOutside Existing Cap and 58,600 ug/kg TCE ActionLevel Inside Existing Cap....................... 4-11

4.2.3.1 Alternative 3a: Vacuum Extraction.............. 4-114.2.3.2 Alternative 3b: In-situ Stream Stripping....... 4-194.2.4 Alternative 4: Limited Treatment of All Soil--

58,600 ug/kg TCE Action Level and Extension ofExisting Cap.................................... 4-24

4.2.4.1 Alternative 4a: Vacuum Extraction, SoilDewatering, and Extension of Existing Cap....... 4-24

4.2.4.2 Alternative 4b: In-situ Steam Stripping andExtension of Existing Cap....................... 4-30

4,2,5 Alternative 5: Limited Treatment of All Soils--34 ug/kg TCE Action Level Outside Existing Capand 58,600 ug/kg TCE Action Level InsideExisting Cap.................................... 4-35

4.2.5.1 Alternative 5a: Vacuum Extraction and SoilDewatering...................................... 4-35

4.2.5.2 Alternative 5b: In-situ Steam Stripping........ 4-384.2.6 Alternative 6: Full Treatment of All Soil--

34 ug/kg TCE Action Level Both Inside and OutsideExisting Cap.................................... 4-40

4.2.6.1 Alternative 6a: Vacuum Extraction and SoilDewatering...................................... 4-40

4.2.6.2 Alternative 6b: In-situ Steam Stripping........ 4-444.3 COMPARISON OF ALTERNATIVES ...................... 4-484.3.1 Technology Comparison........................... 4-484.3.2 Alternative Comparison.......................... 4-48

REFERENCES..................................................... R-l

APPENDICES:

A Subsurface Soil Cleanup Goal Calculations--Summers and HELP Model Simulations.............. Volume 1

B Cost Estimates for Remedial Alternatives........ Volume 1C Calculations.................................... Volume 1D Report on the Results of the Vacuum Extraction

Treatability Study.............................. Volume 2E Report on the Results of the Vacuum Extraction

Treatability Study--Appendices.................. Volume 2

ii

LIST OF TABLES

Table Page

ES-1 Soil Cleanup Goals................................... ES-5

ES-2 Remedial Alternatives................................ ES-7

2-1 Groundwater Protection Standards for Site Contaminants 2-13

2-2 Soil/Water Partition Coefficients and Adsorption Factorsfor Site Contaminants ................................ 2-17

j 2-3 Soil Cleanup Goals................................... 2-19

2-4 Estimated Quantities of TCE Contamination in Soil.... 2-29

« 2-5 Estimated Quantities of Acetone Contamination in Soil 2-31

2-6 Initial Screening of Technology and Process Options.. 2-35I2-7 Evaluation of Source Control Technologies and Process

m Options That Passed Initial Screening................ 2-63

* 3-1 Remedial Alternatives................................ 3-2

1 4 - 1 Criteria for Detailed Analysis of Alternatives....... 4-2f|^Br 4-2 Summary Matrix for Technology Comparison............. 4-49

I 4-3 Summary Matrix for Alternative Comparison............ 4-51

4-4 Comparison of Alternatives by Reduction of Toxicity,\ Mobility, or Volume.................................. 4-67

4-5 Present Worth Comparison of Alternatives............. 4-70

iiiflR30360i

LIST OF FIGURES

Figure Page

1-1 Site Location........................................ 1-5

1-2 Study Area........................................... 1-6

1-3 Locations of Soil Borings............................ 1-9

2-1 TCE Isoconcentration Map for Subsurface Soils(460' MSL)........................................... 2-22





2-6 TCE Isoconcentration Map for Subsurface Soils(410' MSL)........ .................................... 2-27


2-8 TCE Isoconcentration Map for Groundwater(400' MSL)........................................... 2-32

2-9 Acetone Isoconcentration Map for Groundwater(400' MSL)........................................... 2-33

4-1 Proposed Cap Extension Location--RemedialAlternative 2. ....................................... 4-7

4-2 Vacuum Extraction Well Locations--RemedialAlternative 3a....................................... 4-17

4-3 In-situ Steam Stripping Treatment Block Locations--Remedial Alternative 3b.............................. 4-22

4-4 Vacuum Extraction and Dewatering Well Locations--Remedial Alternative 4a.............................. 4-25

4-5 Areas Remediated by Vacuum Extraction and DewateringWells--Remedial Alternative 4a 4-26


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LIST OF FIGURES (cont'd.)

Figure Page

4-7 Areas Remediated by In-situ Steam Stripping—RemedialAlternative 4b....................................... 4-32

4-8 Vacuum Extraction and Dewatering Well Locations--Remedial Alternative 6a.............................. 4-43


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!flR303&04

rEXECUTIVE SUMMARY

INTRODUCTION

This Revised Final Focused Feasibility Study (FS) for the Heleva Landfill Sitehas been prepared for the U.S. Environmental Protection Agency (EPA) underWork Assignment Number 37-05-3L59, Contract Number 68-W8-0037. This FS isbased on the results of the Focused Remedial Investigation (RI) Report(Gannett Fleming, 1990) and the Final Amendment to the RI Report (GannettFleming, 1991). This document replaces the Final Focused FS Report dated June1990. The purpose of this revised FS is to address public comments on thesoil cleanup goal calculations that were submitted to EPA in response to theJuly 1990 Proposed Plan, and to evaluate various alternatives for soilremediation to meet the revised goals. The recalculation of the soil cleanupgoals is presented in the Final Amendment to the Focused RemedialInvestigation Report.

The focus for this FS Is to evaluate a range of remedial alternatives forcontaminated soil at the solvent spill areas, located to the south andsoutheast of the landfill area, so that further contamination of the

I groundwater beneath the site will be minimized. Remedial alternatives for thelandfill area and the groundwater were considered in a previous RI/FS

I conducted by the NUS Corporation in 1985. The remedial actions that havealready been completed or are planned for the Heleva Landfill Site (i.e., thelandfill area cap and the groundwater extraction and treatment facility) willbe incorporated into the overall strategies for addressing the contaminatedsoil areas.

This FS is prepared following the basic methodology outlined in the Final Ruleof the National Oil and Hazardous Substances Pollution Contingency Plan (NCP),

Subpart E, Section 300.430 with consideration of the requirements outlined inSection 121 of the Superfund Amendments and Reauthorization Act (SARA). EPAhas also issued interim guidance on performance of RI/FSs in the form of aguidance document (EPA, 1988a). This guidance, in addition to the provisionsof SARA and the NCP, has been used as the basis for development of this FS.

HR3036Q5

BACKGROUND INFORMATION

The Heleva Landfill Site consists of a 20-acre landfill, located on a 93-acretract of land owned by Stephen Heleva in North Whitehall Township, LehighCounty, Pennsylvania. The site is bounded by Legislative Route 39049 on thesouth and east, Township Route 687 (Hill Street) on the north, and LegislativeRoute 39038 (Main Street) on the west.

The site began operations as a sanitary landfill in 1967 and accepted between250 to 350 tons/day of general mixed refuse, paper, wood, and orchard wastesfrom the Allentown area. In addition to the municipal wastes, industrialwastes were reported to have been sent to the site as early as 1967. Stateinspection reports from the early 1970s indicate that the landfill acceptedhigh volumes of trichloroethene (TCE) liquid wastes from several industries inthe area (EPA, 1985).

Operations at the site continued until its closure by the PennsylvaniaDepartment of Environmental Resources (PADER) on May 1, 1981 because ofoperational deficiencies. As part of the closure procedures, the corporationwas required to cover the landfill with two feet of topsoil and thenrevegetate it. During 1989, the site was enclosed within a fence andconstruction of a cap over the landfill was initiated. The landfill cap wascompleted in May, 1990.

A total of 42 soil borings were drilled during the subsurface investigation tocollect subsurface soil samples for chemical, physical, and geotechnicalanalyses, and groundwater samples for chemical analysis. Two general areas tothe south and east of the landfill area were investigated, designated the "TCESpill Area" and the "Abandoned Building Spill Area."

TCE was the most widespread soil contaminant and generally was detected at thehighest concentrations. TCE levels (up to 110,000 ug/kg) were encountered inBorings GBH01, 02, 04, 05, and 07, which indicates that the true location of

the TCE Spill Area may be to the east of the area that was formerly fenced.Another area with high TCE levels (up to 330,000 ug/kg) was discoveredsurrounding the abandoned building along the site access road. The center of

ES-2 /1R3Q3606

1this spill area is in the vicinity of GBH25, and TCE contamination extends tothe south and east. Concentration profiles of the site show a high degree ofvariability in concentration with depth, with high concentration areasencountered both in the unsaturated soils and near the bedrock below the watertable. Near the water table, the contamination spreads out and intersectssoil borings that had relatively clean soil near the surface. Acetone wasanother contaminant detected at high levels (up to 840,000 ug/kg) in the soilsurrounding the Abandoned Building Spill Area. Moderate concentrations ofchloroform (up to 3,700 ug/kg), another widely used industrial solvent, werealso detected at the site. Fuel-related compounds (benzene, ethylbenzene,toluene, and xylenes) were detected at various locations throughout the site.

Six semivolatile organic compounds were detected in soil samples taken fromI the Abandoned Building Spill Area. No pesticides or polychlorinated biphenyls

(PCBs) were detected in these samples. Inorganic elements in these sampleswere generally in the range typical for similar Eastern U.S. soils.

Groundwater samples usually contained higher concentrations of sitecontaminants than the soil, but had the same relative distribution of sitecontaminants as the soil. Very high levels of acetone, up to 1,900,000 ug/L,

TCE levels up to 930,000 ug/L, and vinyl chloride levels up to 19,000 ug/Lwere encountered in the TCE Spill Area. Groundwater contamination was alsodetected in the vicinity of the Abandoned Building Spill Area.

REMEDIAL ACTION LEVELS

Remediation goals for subsurface soils were developed to limit furthercontamination of the groundwater beneath the site above regulatory standards(i.e., Maximum Contaminant Levels [MCLs]). The Summers Model (Summers,et al., 1980; EPA, 1989a) was used to determine the concentration of acontaminant in unsaturated soil that remedial technologies would need toachieve. Soil contaminants that have maximum concentrations greater than ornearly equal to the cleanup goals calculated by the Summers Model are thefollowing: acetone, benzene, 2-butanone, chloroform, 1,1-dichloroethene,total 1,2-dichloroethene (DCE), methylene chloride, tetrachloroethene,1,1,1-trichloroethane, TCE, and vinyl chloride. If a synthetic membrane cap

ES—3ftR303SQ7

is installed over the contaminated soil areas to minimize the rate ofinfiltration, the Summers Model predicts that only acetone, TCE and methylenechloride would exceed the protection standards for the groundwater. Thecalculated remedial action levels for contaminated soil are presented inTable ES-1.

REMEDIAL ACTION OBJECTIVE

The migration of volatile organic compounds (VOCs) from the subsurface soilsinto the groundwater presents the greatest potential public health andenvironmental threats. To address this threat, the following remedial actionobjective was developed:

" Prevent migration of acetone, benzene, 2-butanone, chloroform, DCE,methylene chloride, tetrachloroethene, 1,1,1-trichloroethane, TCE,and vinyl chloride from the subsurface soils that would result ingroundwater contamination in excess of the respective MCLGs orhealth-based risk concentrations.

This objective can be met by remediating the contaminated soil to the remedialaction levels specified in Table ES-1.

DESCRIPTION OF MAJOR CONTAMINATED MEDIA

The following contaminated media were evaluated in this Focused RI/FS:

* Subsurface soils beneath the existing landfill capSubsurface soils outside the existing landfill cap

* Overburden groundwater

Overburden groundwater, although not the primary focus of the RI/FS, isintimately interrelated with the contaminated soil at the site. Therefore, itis necessary to also evaluate the overburden groundwater since it would be acontinuing source of contamination to the soils and the bedrock aquifer.

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It is estimated that approximately 392,000 cubic yards of soil are above the

TCE remediation goal of 34 ug/kg in the TCE and Abandoned Building spillareas. The existing landfill cap covers approximately 155,000 cubic yards, orroughly 40 percent, of the TCE-contaminated soil. The estimated quantity ofTCE in soil above the 34 ug/kg action level is approximately 11,600 pounds,

and approximately half of this quantity is in soil beneath the landfill cap.Soil contaminated above the 58,600 ug/kg TCE action level is primarily outsidethe existing cap. An estimated 1,500 cubic yards of soil with TCE above58,600 ug/kg is present, primarily at the 420-foot elevation (about 40 feetbelow ground surface).

Estimates of the quantity of acetone-contaminated soils are not as accurate asthat for TCE since all soil samples were not analyzed for acetone during thePhase I field investigation. High levels of acetone were encountered in soilsprimarily outside the boundary of the existing landfill cap. Approximately20,300 cubic yards of soil are contaminated above the 415 ug/kg action levelof acetone, and of this soil, less than 20 percent is inside the boundary ofthe cap. Since acetone is highly water soluble, it is not surprising thathigh concentrations of acetone were only detected near the top of the watertable in the soil.

Overburden groundwater samples generally contained the same contaminants athigher concentrations than the soil samples.

DEVELOPMENT OF ALTERNATIVES

In accordance with 40 CFR 300.430, an initial list of remedial response

actions and associated technologies was identified and screened to meet theremedial action objective. The technologies that passed the screening wereassembled to form remedial alternatives that include containment and treatment

options. Six remedial alternatives were developed for the contaminated soilsas shown in Table ES-2.

Only combinations of general response actions, technologies, and processoptions considered to be the most rational (based on effectiveness,

implementability, and cost) were developed into alternatives. Since only a

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III

TABLE ES-2

REMEDIAL ALTERNATIVES


AlternativeNumber

1

2

3

3a

3b

4

4a

4b

5

5a

5b

6

6a

6b

Alternative Title

No Action

Containment — Extension of Existing Cap

Limited Treatment of Unsaturated Soil — 34 ug/kg TCEAction Level Outside Existing Cap and 58,600 ug/kg TCEAction Level Inside Existing Cap

Vacuum Extraction

In-situ Steam Stripping

Limited Treatment of All Soil — 58,600 ug/kg TCE ActionLevel and Extension of Existing Cap

Vacuum Extraction, Soil Dewatering, and Extensionof Existing Cap

In-situ Steam Stripping and Extension of Existing Cap

Limited Treatment of All Soil — 34 ug/kg TCE Action LevelOutside Existing Cap and 58,600 ug/kg TCE Action LevelInside Existing Cap

Vacuum Extraction and Soil


Dewatering

Full Treatment of All Soil — 34 ug/kg TCE Action Level BothInside and Outside Existing Cap

Vacuum Extraction and Soil


Dewatering

ES-7 flR3036

limited number of remedial alternatives were developed, a preliminaryscreening of alternatives is not warranted and all six alternatives were

retained for detailed analysis.

DESCRIPTION OF ALTERNATIVES

Alternative.....1; No Action

This alternative is considered in the detailed analysis to provide a baselineto which the other remedial alternatives can be compared. This alternativeinvolves taking no further action at the Heleva Landfill Site to remove,

remediate, or contain the contaminated soils and groundwater. Enforcementactions in accordance with the 1985 ROD have already taken place or areunderway, including the installation of a Resource Conservation and RecoveryAct (RCRA)-approved synthetic membrane cap over the landfill area, extendingthe public water supply from Ironton to Ormrod, and the design for an onsitetreatment facility for contaminated groundwaters. This alternative providesno additional reduction in groundwater contamination from the contaminatedsoils, does not meet contaminant-specific Applicable or Relevant andAppropriate Requirements (ARARs), and does not meet the remedial actionobjective.

Alternative 2: Containment--Extension of Existing Cap

This alternative involves containment of the contaminated soils under a lowpermeability cap system. A 30-mil low density polyethylene (LDPE) cap wasrecommended. The cap currently installed over the landfill area would beextended over areas with high soil contamination. The cap extension wouldcover an area of approximately 3.5 acres and would be field seamed to theexisting landfill cap with standard field seaming procedures.

Capping would not reduce the toxicity or volume of contaminants in the soilsand does not provide permanent, irreversible treatment. This alternativewould substantially reduce the mobility of contaminants in the soils byreducing the groundwater recharge rate from approximately 2 in/yr toapproximately 0.0011 in/yr. Residuals remaining after installation of the cap

ES-8

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include the contaminated soils at the site--approximately 392,000 cubic yardsof soil contaminated above the 34 ug/kg action level for TCE. Based on

contaminant modeling with a synthetic membrane cap in place, the drinkingwater criteria for site contaminants would not be met in the groundwaterbeneath soils containing greater than 58,600 ug/kg of TCE. The estimatedvolume of TCE-contaminated soil above the 58,600 ug/kg action level is1,500 cubic yards. This alternative, therefore, does not meet contaminant-specific ARARS or the remedial action objective.

Alternative 3: Limited Treatment of Unsaturated Soil--34 ug/kg TCE ActionLevel Outside Existing Cap and 58.600 ug/kg TCE Action Level InsideExisting Cap

Alternative 3a: Vacuum Extraction

Based on the results of the Evaluation of Source Control TechnologiesI (Gannett Fleming, 1989c) report, vacuum extraction was recommended as the best

available technology for soil remediation at the Heleva Landfill Site, buti

warranted a pilot-scale study due to the difficult soil conditions. An onsitetreatability study was conducted by VAPEX Environmental Technologies, Inc., inFebruary, 1990. The study examined key design and operating parametersincluding: range of influence of vacuum pressure in various soil units, vaporextraction rate, influence of air injection wells and surface capping, andtime to remediate soils to the specified cleanup criteria. A conceptualfull-scale vacuum extraction system for the vadose zone was proposed as twosystems to address shallow soils (up to 25 feet deep) and less permeable deepsoils (25 to 50 feet deep). It is estimated that eight extraction wellsspaced on 100-foot centers would be required to achieve vacuum influence inthe shallow soils of the vadose zone. For the deeper soils between 25 feet

and the top of the water table, approximately 160 extraction wells spaced on20-foot centers would be required. The extraction air flow rates would beapproximately 100 cfm per well in shallow soils and 7 cfm in deeper soils atan operating vacuum of 15 inches of mercury. The estimated time to achievethe cleanup criteria would be approximately one year for the shallow soil andup to five years for the deeper soils, based on chemical modeling in the testarea.

ES-9 HR3036I3

Since some contaminants would be removed from the unsaturated zone to levelsthat meet the cleanup goals, this alternative reduces the volume and toxicityof contaminated soil. Approximately 126,000 cubic yards of soil (3,060 pounds

of VOCs) would be remediated to below cleanup levels. Vacuum extraction isgenerally not effective for treating VOCs that are highly soluble in soilmoisture (e.g., acetone), and therefore may not remediate all of the soilcontaminants to below the cleanup goals at the site. Contaminants present inthe saturated soil zone would not be removed by this alternative. Therefore,although some reduction of contaminant volume would be achieved, it isexpected that the contaminated soil would not be fully remediated by thisalternative, and contaminant-specific ARARs and the remedial action objectivewould not be met.

Alternative 3b: In-situ Steam Stripping

In-situ steam stripping technology is an emerging technology that will beavailable for both continuous and batch treatment operations. As a continuous

system, it is essentially an enhanced vacuum extraction system that includeshot air or steam injection wells within the radius of influence of the vacuumextraction well. As a batch process, steam and hot air are injected throughthe bottom of large-diameter augers and are actively mixed with the soilcolumn until the vapor concentrations from the soil are below specifiedcleanup criteria. Developers of both continuous- and batch-mode technologiesare participating in the EPA Superfund Innovative Technology Evaluation (SITE)Demonstration Program. The batch process will be discussed as arepresentative process option in this FS, although either process may

potentially be applicable for remediating the Heleva Landfill Site.

A large area outside the existing landfill cap would need to be remediated tothe action level of 34 ug/kg TCE. The batch in-situ steam stripping process,which treats approximately 30 square feet in a treatment block, would requireapproximately 3,700 treatment blocks to remediate the spill areas outside ofthe cap. A small area under the cap containing soils with TCE greater than58,600 ug/kg could be remediated with approximately 54 treatment blocks. Theactual number of treatment blocks would be determined in the field by starting

treatment in a known area of contamination and moving outward until soils thatmeet the cleanup criteria were encountered. The time to remediate these areasusing two rigs is approximately five years.

The amount of contaminants removed (3,150 pounds of VOCs) is the same asAlternative 3a, except acetone can also be removed by this technology. Thisalternative is expected to remediate the unsaturated soils to the remedialaction goals but would not affect the saturated overburden soils that maycontinue to contaminate the groundwater. Therefore, this alternative is notexpected to meet contaminant-specific ARARs and the remedial action objective.

Alternative 4: Limited Treatment of All Soil--58.600 ug/kg TCE Action Leveland Extension of Existing Cap

Alternative 4a: Vacuum Extraction, Soil Devatering, and Extension ofExisting Cap

To comply fully with CERCLA, an alternative should utilize treatment thatpermanently reduces the toxicity, mobility, or volume of the contaminants atthe site. Capping alone (i.e., Alternative 2) could not achieve this goal.Capping with hot spot soil remediation, however, would be able to achievecontaminant source reduction to acceptable levels.

To achieve the soil cleanup goals with a synthetic membrane cap, only the "hotspots" of contaminated soil with TCE greater than 58,600 ug/kg need to beremediated. There are two major hot spots, one in the vicinity of boreholeGBH01 in the TCE Spill Area, and the other near borehole GBH25 in theAbandoned Building Spill Area. A total of 18 vacuum extraction wells andapproximately four dewatering wells are needed. Dewatering wells would beinstalled in the same boreholes as the vacuum extraction wells to drain thesaturated soils above bedrock and allow air to flow through the soil to thevacuum extraction wells. The dewatering rates through the low permeabilitysoils are predicted to be extremely low, on the order of 2.6 gallons/day/well.The time estimated for the cap construction is approximately three months, andfor the vacuum extraction/dewatering up to two years including pilot-scaletesting of the dewatering system.

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Capping would significantly reduce the migration of contaminants from the soilto the groundwater. The remediation of hot spots through vacuum extractionand soil dewatering would reduce the soil contaminants to levels that are nolonger of concern for migration to the groundwater once a synthetic membranecap in in place. Approximately 235,000 cubic yards of contaminated soil wouldremain onsite beneath the cap extension. However, 779 pounds of VOCs would beremoved under this alternative. This alternative is expected to reduce thecontaminant migration from the soil to the groundwater by extending the capand by treating the highly contaminated soils to meet the soil cleanup goals.Therefore, this alternative is expected to meet contaminant-specific ARARs andthe remedial action objective of protecting the groundwater.

Alternative 4b: In-situ Steam Stripping and Extension of Existing Cap

This alternative includes using the in-situ steam stripping process, describedunder Alternative 3b, to remediate the contaminated soil hot spots, andplacing a cap over the less contaminated soils. Soils would be treated fromthe surface to the bedrock, including the saturated soil. Unlike vacuumextraction, in-situ stream stripping does not require dewatering to beeffective in the saturated soil zone.

Remediation of the hot spots would be performed in treatment blocks ofapproximately 30 square feet to depths of approximately 70 feet (approximatedepth to the top of bedrock). Assuming a treatment rate of 10 cubicyards/hour, the time to remediate the area with TCE-contaminated soils greaterthan 58,600 ug/kg is approximately one year. Because of the developmentalstatus of this technology, onsite pilot-scale testing may be warranted and mayadd another year to the overall remediation time. Placement of the capextension is estimated to take three months.

Sections of the existing cap over the hot spots would need to be removed to

remediate the soil and be replaced afterwards. Approximately 1,600 squarefeet of cap would be affected.

ES-12

This alternative would treat the contaminated soil hot spots, remediating__ approximately 18,700 cubic yards of soil and removing 1,040 pounds of VOCs.| The remaining contaminated soil would be capped to minimize the mobility of

VOCs into the groundwater. The treated soils may become recontaminated bydiffusion of VOCs from the surrounding untreated soils; however, contaminationlevels should remain below the 58,600 ug/kg TCE action level. Approximately235,000 cubic yards of contaminated soil would remain onsite beneath the cap

i extension. This alternative is expected to meet contaminant-specific ARARsand the remedial action objective and, therefore, reduce the contaminantloading of the groundwater to acceptable levels.

| Alternative 5: Limited Treatment of All Soils--34 ug/kg TCE Action LevelOutside the Existing Cap and 58.600 ug/kg TCE Action Level Inside the

Existing CapIAlternative 5a: Vacuum Extraction and Soil Dewatering

IAs discussed under Alternative 3a, vacuum extraction alone is not effectivefor contaminant removal in saturated soil. Remediation of the saturated soilrequires simultaneous water extraction along with vacuum extraction.Overburden soil dewatering is identified as the technology best suited forthis application.

A conceptual design of this alternative would be similar to that ofAlternative 3a, except that vacuum extraction and dewatering wells would beplaced in the overburden soil below the groundwater table. The average depthof these wells is estimated to be 70 feet. An operating vacuum ofapproximately 15 inches of mercury with an air flow rate of approximately7 cfm per well would be required. Air injection wells would increase theradius of influence of the deep vacuum extraction wells in the lowerpermeability soils. An air injection rate of approximately 70 cfm at anoperating pressure of 50 psi would be required at each designated airinjection wellpoint. Dewatering wells would be equipped with submersiblepumps and are predicted to yield an average flow rate of approximately

2.6 gallons per day at each wellpoint. It is anticipated that the bestdewatering results can be achieved when vacuum extraction and dewatering are

Es-13 flR3036I7

performed in the same well or in a pair of nested wells. The time estimatedfor remediating soils with this alternative is five years.

This alternative would remove approximately 7,000 pounds of VOCs from 237,000cubic yards of soil, mostly from soils outside of the existing cap. Thisrepresents approximately 54 percent of the total contaminants in the soil.Approximately eight shallow soil vacuum extraction wells, 160 deep soil vacuumextraction wells, and 320 dewatering/vacuum extraction wells for saturatedsoils are required to remediate soils outside of the existing landfill cap. Atotal of four dewatering/vacuum extraction wells would have to be installedinside the existing cap boundary to treat the contaminated soil to the cleanupaction level represented by 56,800 ug/kg of TCE. This alternative is expectedto achieve the contaminant-specific ARARs and therefore meet the remedialobjective.


Alternative 5b is similar to Alternative 3b with the exception that thesaturated soils will also be remediated under this alternative. All the otherfeatures of this alternative are the same as Alternative 3b.

Two areas outside the existing landfill cap would need to be remediated to the

action level of 34 ug/kg TCE. The in-situ steam stripping process, whichtreats approximately 30 square feet in a treatment block, would requireapproximately 3,700 treatment blocks to remediate the spill areas outside ofthe cap. A small area under the cap containing soils with TCE greater than

58,600 ug/kg could be remediated with approximately 54 treatment blocks. Theactual number of treatment blocks would be determined in the field by startingin a known area of contamination and moving outward until soils that meet thecleanup criteria were encountered. The time required to remediate these areasusing three rigs is approximately five years.

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This alternative would remove approximately 7,150 pounds of VOCs from thesoil, mostly from soils outside of the existing cap. The total soil volumeremediated would be 237,000 cubic yards. This represents approximately 52

percent of the total contaminants in the soil. It is expected that this

alternative would achieve the contaminant-specific ARARs and therefore meetthe remedial action objective.

Alternative 6: Full Treatment of All Soil--34 ug/kg TCE Action Level BothInside and Outside Existing Cap

Alternative 6a: Vacuum Extraction and Soil Dewatering

In order to achieve full treatment of the overburden soils, it is proposedunder this subaltemative that vacuum extraction be used in conjunction withsoil dewatering to remediate all of the soils within the source areas above

the 34 ug/kg TCE action level. The soil dewatering process would lower thegroundwater table to the point where vacuum extraction becomes effective inthe saturated soils. This alternative is capable of achieving permanent

reduction of the volume of contaminants in the soil which complies with one of

the goals of CERCLA.

It is estimated that 144 wells would be installed through the existinglandfill cap to treat the subsurface soils. A synthetic membrane boot wouldbe placed around each well and field seamed to the cap to maintain a hydraulicbarrier. An additional 165 wells would be necessary for the area outside thelandfill cap. A total of 392,000 cubic yards of soil would be "treated by thisalternative. It is expected that no soil containing contaminants above thecleanup goals would remain in the remediation areas. Approximately12,600 pounds of VOCs would be removed, while about 330 pounds of VOCs wouldremain in soils containing less than 34 ug/kg of TCE. The time required tocomplete remediation would be approximately five years.

It is expected that this alternative would achieve the remedial actionobjective by attaining the contaminant-specific ARARs, and permanently reducethe volume of contaminated soil at the site.

A-R3036I9


This alternative utilizes in-situ steam stripping to achieve full treatment ofthe contaminated overburden soils. The treatment area includes allTCE-contaminated soils within the source areas greater than 34 ug/kg from thesurface to the top of bedrock, both outside and beneath the existing landfillcap.

Remediation of soils beneath the existing landfill cap with a batch in-situsteam stripping process would require that portion of the cap to be removedprior to treatment. Alternatively, the continuous mode steam strippingprocess which utilizes steam injection and vacuum extraction wells could beinstalled without removing the cap over the remediation area. Theimplementability of each technique in a landfill environment has not yet beenwell demonstrated since these are emerging technologies. Further evaluationthrough onsite pilot-scale testing or other field demonstration programs wouldbe required to determine implementation requirements.

Utilizing the batch steam stripping process, approximately 3,650 treatmentblocks would be required outside the existing landfill cap and approximately2,990 treatment blocks would be required for soil under the cap.Approximately 89,600 square feet of cap would need to be removed prior to

treatment. The time required to remediate the area with this alternative isapproximately five years assuming five treatment units operating at the site.

This alternative would be expected to achieve the remedial action objective byattaining the contaminant-specific ARARs, and permanently reduce the volume ofcontaminated soil at the site.

COMPARISON OF ALTERNATIVES

To simplify comparison of the various alternatives and subalternatives, twoseparate comparisons will be presented: a technology comparison and analternative comparison. The technology comparison section providesevaluations of the subalternatives (vacuum extraction and in-situ steamstripping) which apply to each of the four treatment alternatives. The

alternative comparison section evaluates and ranks each of the alternatives

with respect to the nine criteria that EPA uses to evaluate alternatives. Theevaluations in the alternative comparison section mainly focus on differencesin volumes of soil treated and/or contained onsite, rather than differencesbetween treatment technologies.

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HR303622

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1.0 INTRODUCTION

1.1 PURPOSE OF REPORT

This Revised Final Focused Feasibility Study (FS) for the Heleva Landfill Sitehas been prepared for the U.S. Environmental Protection Agency (EPA) underWork Assignment Number 37-05-3L59, Contract Number 68-W8-0037. This FS isbased on the results of the Focused Remedial Investigation (RI) Report

I (Gannett Fleming, 1990) and the Final Amendment to the RI Report (GannettFleming, 1991). The focus for this FS is to evaluate a range of remedialalternatives for contaminated soil at the solvent spill areas, located to the

I south and southeast of the landfill area, so that further contamination of thegroundwater beneath the site will be minimized. Remedial alternatives for the

I landfill area and the groundwater were considered in a previous RI/FSconducted by the NUS Corporation in 1985.

This document replaces the Final Focused FS Report dated June 1990. Thepurpose of this revised FS is to address public comments on the soil cleanupgoal calculations that were submitted to EPA in response to the July 1990Proposed Plan, and to evaluate various alternatives for soil remediation tomeet the revised goals. The recalculation of the soil cleanup goals ispresented in the Final Amendment to the Focused Remedial Investigation Report.

In the development of remedial alternatives for contaminated soil, otherremedial actions that have been completed or are planned for the HelevaLandfill Site will need to be considered. The first action to be consideredis the recently completed synthetic membrane cap over the landfill area. Thesoutheastern edge of this cap now covers part of the contaminated soils thatwere investigated during this RI/FS. The cap will substantially reduce theamount of infiltration through the covered portions of contaminated soil,slowing the rate of contaminant migration. The remedial alternatives will be

developed to incorporate the cap into the overall strategies for addressingthe contaminated soil areas. It is the belief of EPA, expressed to GannettFleming in the project scoping meeting, that the cap will address thepotential problems associated with contaminants in the landfill' material.Therefore, the landfill material has not been considered as part of the scope

1-1 flR303623

of this focused FS. A second remedial action that is currently being plannedby the NUS Corporation, also under Contract No. 68-W8-0037, is groundwaterextraction and treatment for the bedrock aquifer. This extraction andtreatment system will recover contaminated groundwater both near the siteboundary and further downgradient and treat the water to an acceptablequality. Since the near-gradient groundwater treatment facility will belocated in close proximity to the contaminated soil areas, the feasibility ofusing this facility to treat contaminated waters generated during remediationof the soil will be evaluated, and the groundwater treatment system will beincorporated into the remedial alternatives as appropriate.

1.2 ORGANIZATION OF REPORT

This FS is prepared following the basic methodology outlined in the Final Ruleof the National Oil and Hazardous Substances Pollution Contingency Plan (NCP),Subpart E, Section 300.430 with consideration of the requirements outlined inSection 121 of the Superfund Amendments and Reauthorization Act (SARA). EPAhas also issued interim guidance on performance of RI/FSs in the form of aguidance document (EPA, 1988a). This guidance, in addition to the provisionsof SARA and the NCP, has been used as the basis for development of this FS.

The FS process under SARA retains the basic approach for the screening andevaluation of remedial alternatives outlined in the EPA Guidance forConducting Remedial Investigations and Feasibility Studies Under CERCLA (EPA,1988b). SARA Section 121 has modified the FS process to emphasize thedevelopment of remedial alternatives that meet the following conditions:

* Protect human health and the environment.

* Provide permanent solutions to contamination problems and long-termeffectiveness.

* Meet Applicable or Relevant and Appropriate Requirements (ARARs) ona federal level, or a state level if the state requirements are morestringent.

1-2

The emphasis on permanent solutions is directed primarily to source controlactions that eliminate long-term operation and maintenance by permanentlyreducing the mobility, toxicity, and/or volume of the hazardous substances.

The FS methodology is summarized here and described in further detail underthe appropriate sections. The following steps have been used in the FS:

• Establish remedial action objectives (Section 2.2).

* Identify general response actions to meet remedial objectives,including no action (Section 2.3).

1 0 Identify remedial technologies and process options under each_ general response action with emphasis on permanent solutionsI (Section 2.4).

1 ° Screen remedial technologies and process options based on technicalconsiderations; develop remedial alternatives (Section 2.4).

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IDevelop remedial alternatives based on remedial technologies andprocess options (Section 3.1).

Screen remedial alternatives according to effectiveness,implementability, and cost (Section 3.2).

Perform a detailed evaluation of the remedial alternatives based on:short-term effectiveness; long-term effectiveness and permanence;reduction of toxicity, mobility, and/or volume; implementability;cost; compliance with ARARs; overall protection of human health andthe environment; and state and community acceptance (Section 4.0).

Perform a comparative evaluation between remedial alternatives(Section 4.3).

1-3 SR303625

1.3 BACKGROUND INFORMATION

This section provides the site location and description, site history, andsummary of previous investigations associated with the Heleva Landfill Site.The primary sources of this information are the Final Work Plan and the FinalProject Operations Plan (POP) prepared by Gannett Fleming, Inc., in Januaryand March of 1989, respectively, and the RI/FS prepared by the NUS Corporationin September, 1985.

1.3.1 Site Location and Description

The Heleva Landfill Site consists of a 20-acre landfill, located on a 93-acretract of land owned by Stephen Heleva in North Whitehall Township, LehighCounty, Pennsylvania. The site is bounded by Legislative Route 39049 on thesouth and east, Township Route 687 (Hill Street) on the north, and LegislativeRoute 39038 (Main Street) on the west. The center of the site is located at40' 40' 15" north latitude and 75* 33' 40" west longitude on the Cementon,Pennsylvania, U.S. Geological Survey (USGS) quadrangle map. Figure 1-1 showsthe site location, and Figure 1-2 shows the study area.

The landfill was closed in 1981 and covered with a silty and clayey soil takenfrom a borrow area directly south of the landfill boundary. During 1989, thesite was enclosed within a fence and construction of a cap over the landfillwas initiated. The landfill cap was completed in May, 1990.

1.3.2 Site History

The following section is adapted from NUS (1985).

In the late 1800s, the site consisted of a large open-pit iron ore miningoperation. The mining operations, which ended around the turn of the century,

left four open, water-filled pits lying on an east-west line across the site.

The westernmost pond is now known as Todd Lake, while the easternmost pond isan unnamed body of water called "Pond No. 1" during the NUS (1985) RI/FS. Thetwo remaining ponds were covered over during the landfilling operation. One

flR303626

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FIGURE I - IV HELEVA LANDFILL SITE/ LEHIGH COUNTY, PA.

SITE LOCATIONLOCATION

10_____________0______ 10 __ 20

STUDY AREA SCALF 'N MILESGANNETT FUEMING NC., BALTIMORE, MD.

flR303627

of those former ponds was located under the shallow pond which was identifiedas the "Collection Pond" during the 1985 RI/FS, while the other was located

• midway between the Collection Pond and Todd Lake.

| The site began operations as a sanitary landfill in 1967 and accepted between

250 to 350 tons/day of general mixed refuse, paper, wood, and orchard wastesfrom the Allentown area. In addition to the municipal wastes, industrialwastes were sent to the site as early as 1967. State inspection reports fromthe early 1970s indicate that the landfill accepted high volumes oftrichloroethene (TCE) liquid wastes from several industries in the area (EPA,

1 1985).

The site operated through the 1970s without a permit. On May 3, 1977, Heleva£ Landfill, Inc., submitted an application to the Pennsylvania Department of

Environmental Resources (PADER) for a solid waste permit. On July 8, 1977,I this permit application was denied, and the landfill was ordered to cease

operation by the PADER. On July 11, 1977, the corporation filed an appealI ^ with the State Environmental Hearing Board to have the permit denial* P overturned. Subsequently, a consent order was signed by the PADER and Heleva( L a n d f i l l , Inc., on May 19, 1980 to settle the permit appeal. In this consent

order, the corporation agreed to control erosion to Todd Lake, controlleachate generation, limit dumping, and cease dumping in currently filled

I areas. In addition, Mr. Heleva initiated a biostimulation pilot project forTCE reduction in the contaminated soil and groundwater. On November 25, 1980,

I FADER's Bureau of Solid Waste Management again denied Heleva Landfill, Inc.'sapplication to expand the landfill operation because of the corporation'sfailure to implement the biostimulation project completely. Operations at thesite continued until its closure by PADER on May 1, 1981 because ofoperational deficiencies. As part of the closure procedures, the corporation

was required to cover the landfill with two feet of topsoil and thenrevegetate it. Attempts to seed the covered area were not effective due tothe low fertility of the cover material; much of the land had littlevegetation, and many erosion gullies were present.

The site was listed as potentially hazardous on November 15, 1979 by PADER andEPA. A Hazard Ranking System (HRS) model was first generated on August 4,

1982, ?nd updated on September 2, 1982. The aggregate HRS score of 50.22

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resulted in the placement of the Heleva Landfill Site on the National

Priorities List (NPL) .

In 1985, an RI/FS was conducted and a Record of Decision (ROD) was issued forthe site. The selected remedy for the Heleva Landfill Site consisted ofextending an existing water main from Ormrod to Ironton, capping the entire20 -acre landfill according to Resource Conservation and Recovery Act (RCRA)standards, constructing surface water diversion and gas venting systems,conducting a predesign study to fully delineate the source of contaminationand determine sinkhole activity, constructing a treatment facility onsite,pumping and treating highly contaminated groundwater, monitoring and samplingexisting wells and surface water, and conducting operations and maintenancefor a period of at least two years (EPA, 1985) .

A number of remedial responses have occurred over the past 10 years. Thefirst remedial response focused on the West Ormrod Water Association Wellwhich served 35 homes . Because this well was contaminated with volatileorganic compounds (VOCs) , these homes were supplied with water from apermanent outside source in 1987, A second remedial action, directed at thegroundwater contamination, was a biostimulation project by Mr. Heleva toreduce TCE, biochemical oxygen demand (BOD), phenols, and additional organics.Although the site operator claimed that tests showed reductions in thecontaminants, PADER never concurred with these findings. During 1989,construction of an RCRA- equivalent type cap over the landfill was initiated byEPA Region III, and the construction of the cap was managed by the U.S. ArmyCorps of Engineers (ACOE) . A remedial design for contaminated groundwatersthat have migrated off site was undertaken for EPA Region III by the NUSCorporation. Finally, this focused RI/FS for contaminated soils was conductedby Gannett Fleming, Inc.

1.3.3 Nature and forwent of Contamination

A total of 42 soil borings were drilled during the subsurface investigation.The locations of the borings are shown in Figure 1-3. The purpose of the soilborings was to collect subsurface soil samples for chemical, physical, andgeotechnical analyses, and groundwater samples for chemical analysis. All

1-8 AR303630

II chemical samples were analyzed for VOCs, and a subset of these samples were

also analyzed for the full target compound list (TCL) and target analyte list(TAL) contaminants, total petroleum hydrocarbons, and total organic carbon(TOC). The physical and geotechnical analyses that were performed includedmoisture content, specific gravity, bulk density, permeability, consolidation,

compaction, and cation exchange capacity.

The RI field investigation was conducted in two phases. The first phase ofthe investigation focused on delineating the extent of soil contamination inan area along the southern boundary of the landfill that has been called the"TCE Spill Area." During the end of the Phase I investigation, an areapreviously unknown to have highly contaminated soils was discoveredsurrounding an abandoned building along the site access road. The delineation

of this "Abandoned Building Spill Area" was the focus of the Phase IIinvestigation.

TCE was the most widespread soil contaminant and generally was detected at thehighest concentrations. TCE levels (up to 110,000 ug/kg) were encountered inBorings GBH01, 02, 04, 05, and 07, which indicates that the true location of

the TCE Spill Area may be to the east of the area that was formerly fenced.

Another area with high TCE levels (up to 330,000 ug/kg) was discoveredsurrounding the abandoned building along the site access road. The center ofthis spill area is in the vicinity of GBH25 and TCE contamination extends tothe south and east. Concentration profiles of the site show a high degree ofvariability in concentration with depth, with high concentration areasencountered both in the unsaturated soils and near the bedrock below the watertable. Near the water table, the contamination spreads out and intersectssoil borings that had relatively clean soil near the surface.

Acetone was detected at moderate levels (up to 4,500 ug/kg) in the soil in thevicinity of the TCE Spill Area. During the Phase I investigation, acetone wasmeasured in only the 20 percent of the samples submitted for ContractLaboratory Program/Routine Analytical Services (CLP/RAS) analysis since it wasnot suspected to be a major site contaminant. During the Phase IIinvestigation, all samples were analyzed for acetone. Acetone was detected athigh levels (up to 840,000 ug/kg) in the soil surrounding the Abandoned

Building Spill Area. The results indicate that concentrated acetone solutions

1-9 5R30363

were disposed of at the site along with TCE solutions and that the acetone isnot an artifact of the sampling process or laboratory analytical techniques.

Moderate concentrations of chloroform (up to 3,700 ug/kg), another widely usedindustrial solvent, were also detected at the site. Fuel-related compounds(benzene, ethylbenzene, toluene, and xylenes) were detected at variouslocations throughout the site.

Six semivolatile organic compounds were detected in soil samples taken fromthe Abandoned Building Spill Area. No pesticides or polychlorinated biphenyls

(PCBs) were detected in these samples. Inorganic elements in these sampleswere generally in the range typical for similar Eastern U.S. soils.

Groundwater samples usually contained higher concentrations of sitecontaminants than the soil, but had the same relative distribution of sitecontaminants as the soil. Very high levels of acetone, up to 1,900,000 ug/L,TCE levels up to 930,000 ug/L, and vinyl chloride levels up to 19,000 ug/Lwere encountered in the TCE Spill Area, Groundwater contamination was alsodetected in the vicinity of the Abandoned Building Spill Area.

1.3.4 Contaminant Fate and Transport

The environmental fate and transport for the volatiles is complex due to thetypes of soils at the site and the wide variety of interactions that may occurin the soil and landfilled refuse. The most important transport processes aresolubilization and volatilization. The most soluble contaminants, such asacetone, 2-butanone, and methylene chloride, are expected to migrate withpercolating rainwater. The other volatile organics, including the chlorinatedorganics, will also be transported in the water as it percolates through thesoil, but at a slower rate. Due to the fine-grained nature of the soil andits relatively high soil moisture content, it is expected that diffusion ofvolatile contaminants through the soil will be very slow. Therefore, theprimary pathway for contaminant migration will be with infiltrating rainwater.

The rates of migration are estimated to range from 0.84 in/yr forethylbenzene, to 3.5 in/yr for TCE and 5.6 in/yr for acetone. Thus, the soil

1-10 /1R303632

may be expected to be a continuing source of groundwater contamination withdifferent compounds entering the groundwater at different rates.

1.3.5 Soil Cleanup Levels

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Federal drinking water standards and criteria (Maximum Contaminant Levels[MCLs] and Maximum Contaminant Level Goals [MCLGs]) were used to develop soilcleanup goals so that any further contamination leaching from the soils would

. not cause the standards for groundwater to be exceeded. These standards werej used because regulatory criteria for contaminated soils have not been

promulgated. When there was no MCL or MCLG promulgated for a site1 contaminant, a calculated level based on the risk of water consumption was

determined. Based on the results of this analysis, soil concentrations for1 the following contaminants exceed calculated cleanup goals: acetone, benzene,

2-butanone, chloroform, 1,1-dichloroethene, total 1,2-dichloroethene (DCE),I methylene chloride, tetrachloroethene, 1,1,1-trichloroethane, TCE, and vinyl

chloride. The soil cleanup goals are further discussed in Section 2.2.2--Remedial Action Levels.

1.3.6 Environmental Assessment

The RI field investigation revealed two areas along the southern boundary ofthe Heleva Landfill Site that are contaminated with VOCs: the TCE Spill Areaand the Abandoned Building Spill Area. Each area was investigated during thePhase I and Phase II field work. Both the horizontal and vertical extents ofcontamination within the study areas were defined. High concentrations ofseveral VOCs were found. Physical characteristics of the soil were alsodetermined for use in evaluating potential remedial action alternatives.

Soil contamination exceeds calculated cleanup goals for several contaminants.In the contaminated areas, high concentrations of site contaminants arepresent at variable depths from just below the surface to the top of bedrock,indicating that a large volume of soil will require remedial action. Methodsto remediate the site to acceptable levels of soil contamination will beaddressed in this FS.

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2.0 IDENTIFICATION AND SCREENING OF TECHNOLOGIES

2.1 INTRODUCTION

In this chapter, the following four actions in the FS procedure, outlined inSection 1.2, are performed:

Establish remedial action objectives (Section 2.2).

• Identify general response actions to meet remedial objectives,including no action (Section 2.3).

0 Identify remedial technologies under each general response actionwith emphasis on permanent solutions (Section 2.4).

0 Screen remedial technologies based on the short- and long-termaspects of effectiveness, implementability, and cost considerations

(Section 2.4).

2.2 REMEDIAL ACTION OBJECTIVES

Remedial action objectives are based on public health and environmentalconcerns and on a review of ARARs. Available information presented in the RIregarding the contaminants and media of concern, the potential exposurepathways, and the remediation goals were summarized in Sections 1.3.3, 1.3.4,and 1.3.5, respectively. In the following section, ARARs for the HelevaLandfill Site are presented. In Section 2.2.2, ARARs are used to developsite-specific remedial action levels for contaminated soils. Thesite-specific remedial action objective is presented in Section 2.2.3.

2.2.1 Applicable or Relevant and Appropriate Requirements (ARARs')

ARARs may include the following:

0 Any standard, requirement, criterion, or limitation under federalenvironmental law.

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* Any promulgated standard, requirement, criterion or limitation undera state environmental or facility siting law that is more stringentthan the associated federal standard, requirement, criterion, orlimitation.

One of the primary objectives under the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) as amended by SARA is that remedialactions must attain legally applicable or relevant and appropriate federal orstate requirements that assures the protection of human health and theenvironment. ARARs must be identified for each particular site due to the

varied and unpredictable situation prevalent at each site.

Definition of the two types of ARARs as well as other "to be considered" (TBC)criteria are given below:

0 Applicable Requirements means those cleanup standards, standards ofcontrol, and other substantive environmental protectionrequirements, criteriaf or limitations promulgated under federal orstate law that directly and fully address a hazardous substance,contaminant, remedial action, location, or other circumstance at aCERCLA site.

0 Relevant and Appropriate Requirements means those cleanup standards,standards of control, and other substantive environmental protectionrequirements, criteria, or limitations promulgated under federal orstate law, while not "applicable," address problems or situationssufficiently similar (relevant) to those encountered at the CERCLAsite,, that their use is well suited (appropriate) to the particularsite.

0 "To be considered" (TBC) Criteria are nonpromulgated nonenforceableguidelines or criteria that may be useful for developing remedialaction, or necessary for determining what is protective to human

health and/or the environment. Examples of TBC criteria include EPADrinking Water Health Advisories (HAs), Carcinogenic Potency Factors(CPFs), and Reference Doses (RfDs).

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Section 121(d)(4) of SARA allows the selection of a remedial alternative thatwill not attain all ARARs if any of six conditions for a waiver of ARARsexists. The conditions are as follows: (1) the remedial action is aninterim measure whereby the final remedy will attain the ARAR upon completion;

(2) compliance will result in greater risk to human health and the environmentthan other options; (3) compliance is technically impracticable; (4) analternative remedial action will attain the equivalent of the ARAR; (5) for

state requirements, the state has not consistently applied the requirement insimilar circumstances; or (6) compliance with the ARAR will not provide abalance between protecting public health, welfare, and the environment at the

facility with the availability of fund money for response at other facilities(fund-balancing).

ARARs fall into three categories, based on the manner in which they areapplied at a site. The characterization of a particular requirement to aspecific ARAR may not be very accurate, as some requirements are combinations

of the three types of ARARs. The three categories are as follows:

* Contaminant-Specific: Health/risk based numerical values or

methodologies that establish concentration or discharge limits forparticular contaminants. Examples of contaminant-specific ARARsinclude Safe Drinking Water Act (SDWA) MCLs and Clean Water Act(CWA) ambient water quality criteria (AWQC).

0 Location-Specific: Restrictions based on the concentration ofhazardous substances or the conduct of activities in specificlocations. These may restrict or preclude certain remedial actionsor may apply to certain portions of a site. Examples oflocation-specific ARARs include RCRA location requirements and floodplain management requirements.

e Action-Specific: Technology or activity-based controls orrestrictions on activities related to management of hazardous waste.

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2.2.1.1 Contaminant-Specific ARARs and TBC Criteria

This section presents a summary of federal and state contaminant-specificARARs and TBC criteria. All of these ARARs and TBC criteria provide somemedium-specific guidance on "permissible" or "acceptable" concentrations ofcontaminants. The relationship of these criteria to establishing remedialaction goals for the Heleva Landfill Site is discussed.

Federal Safe Drinking Water Act Maximum Contaminant Levels and Goals. TheSDWA, enacted in 1974 and most recently amended in 1986, mandates that EPAestablish regulations to protect human health from contaminants in drinkingwater. EPA has developed two sets of drinking water standards referred to asprimary and secondary drinking water standards. Primary standards consist of

contaminant-specific standards, known as MCLs, and are set at levels that areprotective of human health while considering available treatment technologiesand the costs to large public water systems. MCLs are set as close asfeasible to MCLGs, which are purely health-based goals. Secondary drinkingwater standards consist primarily of Secondary Maximum Contaminant Levels(SMCLs) which are nonenforceable guidelines for specific contaminants orcharacteristics that may affect the aesthetic qualities of drinking water(i.e., color, odor, and taste).

The NCP states that groundwater that is or could be used for drinkinggenerally will be restored to MCLGs that are set above zero. When the MCLGequals zero (generally the case for carcinogens), the corresponding MCL willgenerally be used as the cleanup level. The NCP explains that a cleanup levelof zero is not appropriate for Superfund because CERCLA does not require thecomplete elimination of risk and because it is impossible to detect whether"true" zero has actually been attained (EPA,a 1990).

For the Heleva Landfill Site, the aquifer is classified as a Class IIBgroundwater source, potentially available for drinking water, agriculture, orother beneficial use (EPA, 1986a). The SDWA MCLGs are not applicable

requirements because the contaminated groundwater is not currently provideddirectly to 25 or more people or supplied to 15 or more service connections,

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as per EPA (EPA, 1988f). However, the SDWA MCLGs are relevant and appropriaterequirements as in-situ cleanup standards since the groundwater may be usedfor drinking water after remediation of the aquifer is complete. If nopromulgated standard exists for a given contaminant, proposed MCLs are to begiven greater consideration among the TBC criteria, as per EPA (EPA, 1988f).EPA's Groundwater Protection Strategy (EPA, 1986a) would also be considered asTBC criteria.

Federal Water Quality Criteria. Pursuant to Section 304 of the CWA, EPA

; developed the AWQC as nonenforceable guidance to be used by the states for1 establishing enforceable water quality standards. AWQC for protection of

human health identify protective levels from two routes of exposure--exposurefrom drinking water and consuming aquatic organisms, primarily fish, and from

I fish consumption alone. AWQC standards are applied primarily for theprotection of surface water quality (e.g., regulating point and nonpoint

I source discharges to surface water), but may also be relevant and appropriateto the cleanup of surface and groundwater per CERCLA Section 121 (d)(2)(B)(i).

For groundwater that is or may be used for drinking, MCLs and MCLGs represent_ the level of quality that is safe for drinking and are generally relevant and§ appropriate requirements for groundwater remediation. Therefore, when a

promulgated MCL or MCLG exists for a contaminant at the Heleva Landfill Site,I the AWQC for that contaminant would not be relevant and appropriate, as per

EPA (EPA, 1988f). If no promulgated MCL or MCLG exists for a sitef contaminant, then the appropriate water quality criterion adjusted to reflect

only exposure from drinking the groundwater (since consumption of contaminatedfish is not a concern) may be considered in selecting a cleanup level. If astate water quality standard exists, the state standard is applied rather thanthe federal AWQC because it is an enforceable standard and represents astate-specific adaptation of the CWA criteria.

Federal Clean Air Act. The Clean Air Act (CAA) consists of three categories:National Ambient Air Quality Standards (NAAQS) (40 CFR Part 50), National

Emissions Standards for Hazardous Air Pollutants (NESHAP) (40 CFR Part 51),i .

and New Source Performance Standards (NSPS) (40 CFR Part 60). The EPArequires the attainment of primary and secondary NAAQS to protect public

2-5 RR303639

health and public welfare, respectively. These standards are not source

specific, but are national limits on ambient air intended to protect publichealth and welfare. NESHAPs are emission standards for source types (e.g.,industrial categories) that emit hazardous air pollutants. NSPSs areestablished for new sources-of air emissions to ensure that new stationarysources reduce emissions to a minimum based upon Best Demonstrated Technology(BDT).

To date,, primary NAAQS have been promulgated for carbon monoxide, lead,nitrogen oxides, ozone, particulate matter, and sulfur dioxide. Since thecontaminants of concern at the Heleva Landfill Site are VOCs, the CAA does notrepresent a contaminant-specific ARAR.

Health Effects Assessments. The Health Effects Assessments (HEAs) presenttoxicity data for specific chemicals for use in public health assessments.CPFs and RfDs, provided in the Superfund Public Health Evaluation Manual (EPA,1986) and subsequent updates, are also used for risk assessment purposes.

These data may be applied as TBC criteria for developing cleanup goals of sitecontaminants if federal and state criteria, advisories, or guidance do notmeet the definitions of ARARs.

Pennsylvania Safe Drinking Water Act. Under Title 25 of the PennsylvaniaCode, Chapter 109, the Pennsylvania SDWA sets forth drinking water qualitystandards at least as stringent as the National Primary Drinking WaterRegulations. MCLs that are promulgated by the EPA are automatically

incorporated into the Pennsylvania SDWA. If an MCL does not exist for acontaminant, the Pennsylvania SDWA requires the maximum allowableconcentration be determined in the following order: 1) the concentration thatEPA has proposed to set or is considering setting as a primary MCL for thecontaminant; 2) the concentration associated with a lifetime cancer risk of10"6 for carcinogenic contaminants or the lifetime drinking water healthadvisory concentration for noncarcinogenie contaminants, provided that thisconcentration is equal to or greater than the practical quantitation level andthe level achievable through the use of available treatment technology; or

3) the lowest concentration achievable considering the practical quantitationlevel and available treatment technology.

2-6

For the Heleva Landfill Site, the Pennsylvania SWDA does not alter therelevant and appropriate requirements of meeting MCLGs in the groundwater asthe goal for remediation of the site.

Pennsylvania Water Quality Criteria. The Pennsylvania Water Quality Criteria(WQC) establish standards for the control of substances from either point ornonpoint source waste discharges in concentrations harmful to human, animal,plant, or aquatic life. Pennsylvania, by reference, adopts the federal AWQCfor protecting waters of the Commonwealth.

For contaminants at the Heleva Landfill Site that MCLs and MCLGs have been

promulgated for, the Pennsylvania WQC are not contaminant-specific ARARs. Ifan MCL and MCLG for a site contaminant does not exist, then the PennsylvaniaWQC may be applied as TBC criteria if they are more stringent than federalcriteria.

Pennsylvania Air Pollution Control Act. The Pennsylvania Air Pollution

Control Regulations adopt by reference the federal NAAQS, NESHAP, and NSPSregulations. Under Title 25, Chapter 127 regarding "Construction,Modification, Reactivation and Operation of Sources," new sources are requiredto use best available technology for air pollution control, meet with thePADER's approval for plan and operating permit requirements, and adhere tospecial requirements for sources in nonattainment areas.

The VOCs of concern at the Heleva Landfill Site are not specifically addressedunder the Pennsylvania Air Pollution Control Act. These regulations,therefore, would not constitute contaminant-specific ARARs.

2.2.1.2 Location-specific ARARs

The Endangered Species Act of 1973. (16 USC 1531) (40 CFR Part 502) This actprovides for consideration of the impacts on endangered and threatened speciesand their critical habitats. The act requires federal agencies, inconsultation with the Secretary of the Interior, to ensure that any actionauthorized, funded, or carried out by the agency is not likely to jeopardizethe continued existence of any endangered or threatened species or adversely

affect its critical habitat. If the Secretary determines that such species

2-7 RR3036M

may be present, the federal agency must conduct a biological assessment toidentify any endangered or threatened species likely to be affected by theagency's ac t ion.

In 1985, the U.S. Department of the Interior (DOI) performed a preliminarynatural resources survey for the Heleva Landfill Site. The survey found thatthe only DOI trust resources that can possibly be affected by contamination atthe Heleva Landfill are migratory birds. The report further stated that theVOCs present in surface water and groundwater are at concentrations that poseno threat to aquatic life and do not significantly bioaccumulate. Therefore,the DOI concluded that there is no direct or presumptive evidence of adverseimpacts to migratory birds or other fauna that occur in the area. The reportrecommended that the DOI should grant an unconditional release from claims fordamages to DOI trust resources (i.e., migratory birds) because it is veryunlikely that hazardous substances from the Heleva Landfill have had or willhave detectable impacts on the resources (DOI, 1985).

In light of the DOI's findings, the Endangered Species Act does not serve as alocation-specific ARAR for the Heleva Landfill Site.

2.2.1.3 Action-Specific ARARs

Resource Conservation and Recovery Act. (40 CFR Part 264) RCRA Subtitle Cregulates the treatment, storage, and disposal of hazardous waste from itsgeneration until its ultimate disposal. In general, RCRA Subtitle Crequirements for the treatment, storage, or disposal of hazardous waste willbe applicable if:

0 The waste is a listed or characteristic waste under RCRA, and

0 The waste was treated, stored, or disposed after the effective dateof the RCRA requirements under consideration (November 19, 1980), or

' The activity at the CERCLA site constitutes current treatment,storage, or disposal as defined by RCRA.

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I1I

RCRA Subtitle C requirements may be relevant and appropriate when the waste issufficiently similar to a hazardous waste and/or the onsite remedial actionconstitutes treatment, storage, or disposal, and the particular RCRArequirement is well-suited to the circumstances of the contaminant release and

site. RCRA Subtitle C requirements may also be relevant and appropriate whenthe remedial action constitutes generation of a hazardous waste. Onsiteactivities, mandated by a federally ordered Superfund cleanup, must comply

with the substantive requirements of RCRA Subtitle C but not with theadministrative requirements (i.e., permits) of RCRA. All RCRA Subtitle Crequirements must be met if the cleanup is not under federal order and/or whenthe hazardous waste moves offsite.

RCRA Subtitle C requirements for treatment, storage or disposal of hazardouswaste are not applicable to the Heleva Landfill Site. The site does notcontain a RCRA listed waste or characteristic hazardous waste that was treatedor disposed of after the effective date of the RCRA regulations. RCRA

Subtitle C requirements, however, may be relevant and appropriate for remedialactions that involve treatment, storage, or disposal of wastes that aresimilar or identical to a RCRA hazardous waste. RCRA requirements forcontainer storage, tank storage, and capping may be relevant and appropriate

for the site.

Container and tank storage requirements would be relevant and appropriate forthe onsite storage of drilling fluids, spent activated carbon, or wastewaterif they contain a RCRA listed or characteristic hazardous waste. In general,these requirements would only apply to storage of wastes for longer than90 days. Offsite transport of these wastes would require disposal ortreatment by RCRA-permitted facilities.

RCRA requirements for capping may also be relevant and appropriate. Cappingthe contaminated soils at the Heleva Landfill Site may be necessary to meetremedial action objective. When the situation at a CERCLA site requires thepartial use of RCRA regulations, the situation is identified with the term"hybrid." Thus, at Heleva, hybrid capping requirements may be relevant andappropriate.

2-9 flR3036i*3

Federal Clean Air Act. In general, requirements of the CAA (e.g., NAAQS,NESHAPs and NSPS) are not applicable to CERCLA remedial actions, as per EPA(EPA, 1989c). NAAQS apply to "major sources" which do not include most CERCLAremedial activities. Likewise, NESHAPs and NSPS are not applicable toSuperfund remedial activities because CERCLA sites do not usually contain oneof the specific source categories regulated. CAA requirements, however, maybe relevant and appropriate for remedial actions that emit regulatedpollutants.

For the Heleva Landfill Site, the NESHAPs for vinyl chloride (10 ppm) and

benzene (no detectable emissions) may apply to remedial activities producingemissions of these chemicals.

Occupational Safety and Health Act. The Occupational Safety and Health Act(OSHA) regulations (29 CFR Parts 1904, 1910 and 1926) identify occupational

safety and health requirements applicable to workers in the workplace. Theseregulations apply to work performed during the implementation of a remedialaction.

Department of Transportation Rules for Hazardous Materials Transport. TheDepartment of Transportation (DOT) rules (49 CFR Parts 107 and 171-179)regulate the transport of hazardous materials, including packaging, shippingequipment, and use of placards. These rules are applicable to wastes shippedoffsite for laboratory analysis, treatment, or disposal.

Federal Clean Water Act. Requirements of the CWA, as amended, address the

discharge of wastewaters to surface water through the National PollutantDischarge Elimination System (NPDES). NPDES requirements (40 CFR Part 122)may be relevant and appropriate if remedial actions require the discharge to

surface waters. Discharges of wastewater to onsite surface waters do notrequire NPDES permits. However, onsite discharges must meet substantiverequirements of the law.

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Threshold Limit Values. The American Conference of Governmental IndustrialHygienists develop airborne contaminant concentration limits that are believedto be protective of worker health. Two sets of threshold limit values (TLVs)are developed--a time weighted average (TWA) for a normal 8-hour workday and a40-hour workweek, and a short-term exposure limit (STEL). TLVs are TBCcriteria for protection of workers during remedial activities.

Pennsylvania Air Pollution Control Act. Several chapters of the State's AirPollution Control Act (APCA) may be applicable or relevant and appropriate tothe site. In general, Chapter 127 requires new air contaminant sources toreduce emissions to the minimum attainable level through the use of bestavailable technology (BAT). Other chapters identifying requirements for the

reporting of sources (Chapter 135), air quality standards (Chapter 131), andsampling and testing (Chapter 139) may be relevant and appropriate for

remedial activities at the site. Pennsylvania has developed a state plan tomeet federal ambient standards and issues permits for point sources.

Pennsylvania Storm Water Management Act. Chapter 111 (25 Pennsylvania Code

Chapter 111.1) sets forth provisions governing the awards of grants tocounties and municipalities for preparing and implementing stormwatermanagement plans. Remedial activities at the Heleva Landfill Site may require

stormwater management systems.

Pennsylvania Hazardous Substance Transportation Regulations. Requirements forthe transportation of hazardous wastes are codified in Title 13 of thePennsylvania Code for flammable liquids and flammable solids, and underTitle 15 for oxidizing materials, poisons and corrosive liquids. Any offsiteshipment of wastes generated during remedial activities would have to complywith these regulations.

Pennsylvania Solid Waste Management Act. Subchapter D (25 Pennsylvania CodeSections 75.259-75.282) of the Solid Waste Management Act (SWMA) applies tothe identification, listing, generation, transportation, storage, treatment,and disposal of hazardous waste. Also included under this subchapter are therequirements under RCRA for a state to implement a federally approvedhazardous waste program. Pennsylvania has been delegated the authority to

2-11

implement most but not all of RCRA. The State implements independent programsfor other types of solid waste management not covered by the federal law.

Pennsylvania Clean Streams Law. Chapter 92 (25 Pennsylvania Code Chapter 92)of the Clean Streams Law (CSL) sets forth provisions for the administration ofthe NPDES program within the State and establishes criteria for the content ofNPDES permit applications, effluent standards, monitoring requirements,standard, permit conditions, public notification procedures, and otherrequirements related to the NPDES program. In general, Superfund sites arenot required to obtain NPDES permits; however, remedies must meet thesubstantive requirements of the law.

Chapter 102 (25 Pennsylvania Code Chapter 102) of the CSL sets forthrequirements for the control of soil erosion and sedimentation resulting fromearthmoving activities. Remedial activities (e.g., capping) underconsideration for the Heleva Landfill Site may require the disturbance ofsoil.

2.2.2 Remedial Action Levels

Remediation goals for subsurface soils were developed in Chapter 6 of the RI.The contaminated soils are a concern at the site because they are a currentsource of contamination to the groundwater. Since enforceable federal orstate standards have not yet been promulgated for contaminated soils, theremediation goals were based on meeting contaminant-specific ARARs for thegroundwater beneath the site.

The NCP specifies that non-zero MCLGs shall be attained by remedial actionsfor groundwater or surface waters that are current or potential sources ofdrinking water. When the MCLG for a contaminant has been set at zero, apromulgated or proposed MCL for that contaminant shall be used instead of theMCLG. When there is no MCL or MCLG set for a toxicant or carcinogen, acalculated level based on the risk of water consumption can be used in theirplace (EPA, 1990). Table 2-1 summarizes these groundwater protectionstandards (GWPS) for soil contaminants found at the Heleva Landfill Site.

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TABLE 2-1

GROUNDWATER PROTECTION STANDARDS FOR SITE CONTAMINANTS


Contaminant

Acetone

Benzene

2-Butanone

Chlorobenzene

Chloroform

1 , 1-Dichloroethane

1 , 1-Dichloroethene

cis 1,2-Dichloroethene

trans 1,2-Dichloroethene

Ethylbenzene

Methylene Chloride

Tetrachloroethene

Toluene

Trichloroethene

1,1, 1-Trichloroethane

Vinyl Chloride

Total Xylenes

MCL(ug/L)

NP

5

NP

100

NP

NP

7

70

100

700

5

5

2,000

5

200

2

10,000

MCLG(ug/L)

NP

0

NP

100

NP

NP

7

70

100

700

0

0

2,000

0

200

0

10,000

CalculatedValuesBased onRisk(ug/L)

3,500

1,890 (a)

100 (a)

440 (a)

Notes: NP = Not Promulgated(a) = EPA Region III determined value (memorandum dated

December 17, 1990)

2-13

A soil cleanup goal is defined as the concentration of a contaminant inunsaturated soil that remedial technologies need to achieve to preventcontamination of groundwater above regulatory standards (e.g., MCLs). Cleanup

goals for the site are calculated using the Summers Model (Summers, et al.,

1980; EPA, 1989a).

The Summers Model assumes that a percentage of rainfall at the site will

infiltrate the surface and desorb contaminants from the soil based onequilibrium soil/water partitioning. It is further assumed that this

contaminated infiltration will mix completely with the groundwater below the

site, resulting in an equilibrium between groundwater and soil contaminantconcentrations.

The Summers Model begins by estimating the concentration of contaminants inthe infiltrating water (leachate) that would result in groundwaterconcentrations at or below target levels. For this model, the mixing rate of

infiltration and groundwater is estimated. The contaminant concentration in

the groundwater cue to the mixing ot uncontaminated groundwater withcontaminated infiltration can be calculated using the following equation:

(QpCp)

CgwQp + QA (2-D

where:

Cgw " Contaminant concentration in the groundwater (ug/L)Qp - R x L x W volumetric fluw rate of infiltration (soil pore

water) into the aquifer (ft /day)R — Yearly average recharge or Darcy velocity in the downward

direction (ft/yr)L - Length of the pond or spill area (ft)W - Width of the pond or spill area (ft)Cp - Contaminant concentration in the infiltration at the

unsaturated-saturated zone interface (ug/L)QA - V x W x H - volumetric flow rate of groundwater (ft /day)V - Darcy velocity in aquifer (ft/yr)H - Effective aquifer mixing depth (ft)

2-14

II The maximum allowable contaminant concentration in the infiltration that would

not result in a groundwater concentration exceeding a GWPS such as the MCL canbe determined by substituting the GWPS for Cgw in Equation 2-1 and solving forthe infiltration contaminant concentration (Cp) as follows.

(Qp + QA)

Cp - _____________ (2-2)

Once the maximum allowable contaminant concentration in the leachate has beenI determined, the contaminant concentration in the soil can be calculated. This

is the soil cleanup level which needs to be attained in order to be protective

I of the groundwater. The soil concentration can be derived from the followingsoil/water partitioning equation:

•

I!

Cs - (Kd) (Cp)

or GWPS x Kd (Qp

Cs - ____________ (2-3)

where:

Cs - Contaminant concentration on soil (ug/kg)Cp - Contaminant concentration in the infiltration (ug/L)Kd - Equilibrium partition coefficient (ml/g)

Replacing the volumetric flow terms with the Darcy velocities and thedimensions of the contaminated zone, Equation 2-3 can be written as:

GWPS x Kd ((R x L) + (V x B))

(R x L) (2-4)

The equilibrium partition coefficient (Kd) for each contaminant can beestimated from literature values of partition coefficients between organic

2-15

carbon and water, and the fraction of organic carbon in the soil. A commonlyused equation for this purpose is as follows (EPA, 1988a):

x foc (2-5)

where:

Kd - Distribution factor for soil (ml/'g)Koc - Soil/water partition coefficient for organic carbon (ml/g)foc - Fraction of organic carbon in soil

Table 2-2 is a summary of literature values for KQC and calculated Kd valuesfor the site contaminants. The organic carbon fraction in the soil (foc) wascalculated as the average percent of total organic carbon (TOG) measured in 59soil samples and had a value of 0.1412.

The rate (Qp) or velocity (R) at which water percolates downward through thesoil is a function of the soil types, soil moisture content, surfacevegetation and slope, and presence of barriers such as the synthetic membranecap that has been constructed over the landfill at the Heleva Landfill Site.

The Hydrologic Evaluation of Landfill Performance (HELP) Model (EPA, 1984) wasused to estimate the average annual groundwater recharge in the contaminatedsoil areas. Two scenarios were considered for the TCE and Abandoned Buildingspill areas: existing soil conditions with no cap and placement of asynthetic membrane cap over the contaminated areas. With no cap, thegroundwater recharge beneath the TCE and Abandoned Building spill areas waspredicted to be 2 inches per year. A synthetic membrane cap would virtuallyeliminate infiltration, as shown by a predicted groundwater recharge of 0.0011inches per year. Calculations are presented in Appendix A.

2-161*303650

1

iII

TABLE 2-2

SOIL/WATER PARTITION COEFFICIENTS AND ADSORPTION FACTORSFOR SITE CONTAMINANTS


Contaminant

Acetone

Benzene

2-Butanone

Chlorobenzene

Chloroform

1, 1-Dichloroethane

1, 1-Dichloroethene

cis 1,2-Dichloroethene

trans 1,2-Dichloroethene

Ethylbenzene

Methylene Chloride

Tetrachloroethene

Toluene

1,1, 1-Trichloroethane

Trichloroethene

Vinyl Chloride

Total Xylenes

Koc(ml/g)

2.2

83

4.5

330

31

30

65

49

59

1100

8.8

364

300

152

126

57

240

Kd(ml/g)

0.0031

0.1172

0.0064

0.4660

0.0438

0.0424

0.0918

0.0692

0.0833

1.553

0.0124

0.5140

0.4236

0.2146

0.1779

0.0805

0.3389

Reference: EPA, 1986

2-17 &R3Q3651

Other parameters required for Equation 2-4 are the length of the site parallelto groundwater flow, the groundwater velocity, and effective aquifer mixingdepth. The length of the site parallel to the groundwater flow (L) wasestimated to be 250 feet, based on areas of known contaminant release to theground surface. The Darcy velocity (V) was estimated to be 42.7 ft/day ascalculated from the hydraulic conductivity and hydraulic gradient valuespresented in the remedial design performed by NUS (1989). The effectiveaquifer mixing depth (H) was calculated by the Woodward-Clyde equation to beapproximately 36 feet. Calculations of the Darcy velocity and the effectiveaquifer mixing depth are presented in Appendix A.

Soil contaminants that have maximum concentrations greater than or nearlyequal to Cs values calculated by the Summers Model when there is no cap inplace are the following: acetone, benzene, 2-butanone, chloroform,1,1-dichloroethene, DCE, methylene chloride, tetrachloroethene,1,1,1-trichloroethane, TCE, and vinyl chloride. If a synthetic membrane capis installed over the contaminated soil areas, the Summers Model predicts thatonly acetone, TCE and methylene chloride would exceed the protection, standardsfor the groundwater. The soil cleanup goals for the Heleva Landfill Site fordifferent capping scenarios are presented in Table 2-3.

2.2.3 Remedial Action Objective

As discussed in the contaminant fate and transport summary (Section 1.3.4),the primary pathway for contaminant migration is percolation through thesubsurface soil into the groundwater. Contaminants in the surface soils(i.e.. 0 to 2 feet deep) have volatilized into the atmosphere and generally donot pose a public health risk. Due to the fine-grained nature of the soil(predominantly silt and clay) and its relatively high moisture content, it isexpected that VOCs in the deeper subsurface soils will not readily diffuse tothe surface and, therefore, do not represent a major public health threatthrough this pathway.

Since the migration of VOCs from the subsurface soils into the groundwaterpresents the greatest potential public health and environmental threats, thefollowing remedial action objective was developed:

2-18 SR303652

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in Table 2-1.

2.3 GENERAL RESPONSE ACTIONS

This section identifies general response actions that can be implemented tomeet the remedial action objective identified in Section 2.2. A description

and estimated volume of the contaminated media are given along with adiscussion of the primary contaminants.

General response actions are medium-specific, generic actions that willsatisfy the remedial action objective to various degrees. Four generalresponse actions were identified for the contaminated soil as follows:

9 No Action9 Institutional Actions

0 Containment9 Treatment

2.3.1 Description of Major Contaminated Media

The following contaminated media were evaluated in this Focused RI/FS:

' Subsurface soils beneath the existing landfill cap* Subsurface soils outside the existing landfill cap• Overburden groundwater

Overburden groundwater, although not the primary focus of this RI/FS, isinterrelated with the contaminated soil at the site. Therefore, for the FS,it is necessary to also investigate the overburden groundwater since it wouldbe a source of contamination to the bedrock aquifer. If the overburden

2-20

1

groundwater is not considered in this analysis, it has the potential, due tohigh contaminant concentrations , to recontaminate treated soils and conveycontaminants to the bedrock aquifer, thereby preventing the remedial actionobjective from being met.

As discussed in Section 1.3.3, TCE was found to be the most widespread soilcontaminant and generally was detected at the highest concentrations. Highconcentrations of acetone were also observed, but in fewer sampling locationsthan TCE. The quantity of all other VOCs detected summed to approximately10 percent of the estimated quantity of TCE present in the contaminated soils.TCE, therefore, was selected as the representative contaminant for the soilcontamination and will be used in the remainder of this FS report to developaction levels for remedial technologies and alternatives. Processes that areapplicable for remediating TCE -contaminated soils are expected to remove otherVOCs detected at the site, with the exception of highly water solublecompounds such as acetone and 2-butanone. Special considerations involved inremoving highly water soluble VOCs will be discussed in this FS report asappropriate .

To estimate the quantities of soil contaminated above the remediation goals, acomputer program was used to generate Isoconcentration maps such as thosepresented in Figures 2-1 through 2-7 for TCE. Each map represents a change inelevation of 10 feet starting from the surface (approximately 460 feet meansea level [MSL] ) to the bedrock (approximately 400 feet MSL) . The logarithmic

I isoconcentration lines are derived from a statistical process called krigingwhich estimates the concentration in a given area using a weighted movingaverage interpolation between the measured concentrations at the soil borings.In Table 2-4, the areas encompassed by TCE isoconcentration lines of 34 ug/kgand 58,600 ug/kg are presented. The volume of soil is calculated bymultiplying these areas by a 10-foot depth. It is estimated thatapproximately 392,000 cubic yards of soil are above the TCE remediation goalof 34 ug/kg in the TCE and Abandoned Building spill areas. The existinglandfill cap covers approximately 155,000 cubic yards, or roughly 40 percent,of the TCE -contaminated soil. The estimated quantity of TCE in soil above the34 ug/kg action level is approximately 11,600 pounds, and approximately half

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of this quantity is in soil beneath the landfill cap. Soil contaminated abovethe 58,600 ug/kg TCE action level is primarily outside the existing cap. Anestimated 1,500 cubic yards of soil with TCE above 58,600 ug/kg is present,primarily at the 420-foot elevation (about 40 feet below ground surface).

Estimates of the quantity of acetone-contaminated soils are not as accurate asthat for TCE since all soil samples were not analyzed for acetone during thePhase I field investigation. Table 2-5 summarizes the area, volume, andquantity of the acetone-contaminated soils estimated from the Phase II fieldinvestigation data (Borings GBH29 through 43). High levels of acetone wereencountered primarily in soils outside the boundary of the existing landfillcap. Approximately 20,300 cubic yards of soil are contaminated above the415 ug/kg action level of acetone, and of this soil, about 18 percent is

inside the boundary of the cap. Since acetone is highly water soluble, it isnot surprising that high concentrations of acetone were detected only near thetop of the water table in the soil.

Overburden groundwater samples generally contained higher concentrations ofsite contaminants than the soil samples. This may partially be due to sampleand analysis techniques for groundwater samples which tend to measure VOCsmore accurately than techniques used for soil samples. These results againshow that high concentrations of the site contaminants are in the saturatedsoil. Figures 2-8 and 2-9 present TCE and acetone isoconcentration maps forgroundwater samples taken near the top of the water table at approximately400 feet MSL. These maps show that a contaminated plume may extend to thesouth and east of the spill areas, following the regional groundwater flowtowards Coplay Creek, and may also extend to the northeast towards Pond No. 1,indicating a local northeasterly gradient.

2.4 IDENTIFICATION AND SCREENING OF TECHNOLOGIES AND PROCESS OPTIONS

In accordance with 40 CFR Part 300.430, potential remedial technologies andprocess options were identified and screened according to their overallapplicability to the primary contaminants and conditions present at the Heleva

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2-33

Landfill Site. The technologies and process options were initially screenedin the Evaluation of Source Control Technologies. Heleva Landfill Site(Gannett Fleming, 1989c) report. A summary of the identification and initialscreening of potential remedial technologies is given in Table 2-6.

The remedial technologies and process options discussed in this initial

screening are evaluated further in this section based on the following threecriteria:

1. Effectiveness

0 Protection of human health and environment; reduction in toxicity,

mobility, and volume; and permanence of solution.

" Ability of the technology to handle the estimated areas or volumes

of contaminated medium.

e Ability of the technology to meet the remediation goals identified

in the remedial action objective,

0 Technical reliability (innovative versus well proven) with respect

to contaminants and site conditions.

2. Implementability

• Overall technical feasibility at the site and compatibility with

existing cap.

0 Availability of vendors, mobile units, storage and disposal

services, etc.

0 Administrative feasibility.

0 Special long-term operation and maintenance (O&M) requirements.

2-34 5R303668

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3. Cost

0 Qualitative evaluation of construction and long-term O&M costs.

" Comparison of the magnitude of cost to the overall effectiveness ofthe technology.

0 Comparison to other technologies that provide similar effectivenessand implementability but at different costs.

All of the items listed under each criterion may not apply directly to eachtechnology, and therefore each item will be addressed only where appropriate.

Since a detailed discussion of technologies and process options has alreadybeen presented in the Evaluation of Source Control Technologies. HelevaLandfill Site report, only a summary of technology discussions will be

presented in this section. Technologies and process options which passed thisinitial screening (e.g., vapor extraction technologies) are discussed ingreater detail than the technologies and process options that were screenedout (e.g., thermal and biological treatments).

For each technology, representative processes are selected, where possible andappropriate, in order to more effectively facilitate the subsequentdevelopment and evaluation of alternatives without limiting flexibility duringremedial design. The specific process actually used to implement the remedialaction at the site may be selected in the ROD, during the remedial designphase, cr in the bid evaluation/selection of the remedial action contractorand may differ from the selected representative process.

2.4.1 No Action

Since enforcement actions have already taken place at the Heleva Landfill Sitein accordance with the 1985 ROD, the "no action" option essentially means "nofurther action." It involves leaving the site as it is. Actions alreadytaken are the extension of a municipal water supply from Ironton to Ormrod,

2-38 /JR303672

I

I

and the capping of the landfill area. The no action option is considered inthe FS to provide a baseline to which other remedial technologies can becompared.

Effectiveness

The existing landfill cap will be effective at reducing the mobility ofcontaminants from the landfill material and soils that are beneath the cap.Data obtained during the RI field investigation show significant areas of soiland groundwater contamination that are outside the limits of the landfill cap.The no action option does not address this problem and contaminants wouldcontinue to migrate from contaminated soil to the underlying groundwater. Theno action option would not further reduce the toxicity, mobility, or volume ofcontaminants at the Heleva Landfill Site and would not achieve the remedialaction goals for the subsurface soils and groundwater.

Implementability

No implementation is required.

I Cost

1 No further costs would be incurred.

Conclusion

Retain no action for comparison purposes.

2.4.2 Institutional Actions

Institutional actions which may include site access restriction and air orgroundwater monitoring were not considered relevant to the focused scope ofthis FS. These actions are normally considered on a sitewide basis, as wasdone during the 1985 RI/FS for the Heleva Landfill Site, and will thereforenot be addressed in this study.

2-39 flR303673

2.4.3 Containment

Three general categories of containment were considered: capping, bottomsealing, and excavation with either onsite or offsite disposal in a secureRCRA landfill. Vertical barriers (i.e., grout curtains) were not consideredbecause the contaminated soil is either unsaturated or has only very low ratesof groundwater movement.

1. Capping

There are several types of impermeable materials that are used for caps. Theyinclude the following:

0 asphalt or concrete

* low permeability soils

* soil admixtures

0 synthetic membranes

Because of the concern ovet the long-term effects of aging, creep, subgrademovement, and freeze/thaw damage, asphalt and concrete will not be consideredfor capping at this site.

A low permeability soil cap consists of clays or other natural soils that havea compacted in-place hydraulic conductivity of not more than 1x10"1 cm/sec.Soil admixtures used for capping include bentonite, cements, lime, fly ash,bottom ash, and furnace slag. Admixtures are generally used when adequatequantities of low permeability soil are not readily available. They are mixedwith onsite soils to produce a low permeability cap. Synthetic membranesutilized for caps include polyvinyl chloride (PVC), high density polyethylene(HOPE), low density polyethylene (LDPE), chlorinated polyethylene (CPE),chlorosulfonated polyethylene (CSPE), and various types of rubber. The capthat has been constructed over the landfill area at the Heleva Landfill Siteincludes a 60-mil HOPE liner.

2-40

Effectiveness

Capping provides an effective means of controlling the mobility ofi

contaminants from the vadose zone to the groundwater. Synthetic membranes are

expected to be the least permeable. Local soils generally have lowpermeability; therefore, the use of soil admixtures does not need to beconsidered. A low permeability soil cap would not be significantly less

i permeable than the silt and clay soils in the spill areas which have ahydraulic conductivity on the order of 1 x 10*7. A low permeability soil cap

J is therefore not considered an effective alternative.

i Although capping does not provide any treatment of the contaminated soils, itmay meet the remediation goals identified in the remedial action objective by

I effectively eliminating the mobility of contaminants into the groundwater.

ImplementabllitvIAn extension to the landfill cap could be readily implemented. Since the capextension would cover the existing equipment staging area and parking lot, newareas may need to be constructed depending upon the amount of future site workthat is required.

The cap extension should be constructed of a synthetic membrane. There wouldbe difficulty seaming PVC, CPE, CSPE or rubber membranes to the existing HDPEcap. Therefore, only HDPE and LDPE should be considered for a synthetic

membrane cap extension.

Cost

The cost of constructing the existing t HDPE cap over the 20-acre landfillsection was approximately $500,000 per acre. The cost for a cap extension

constructed of LDPE material is estimated to range from $155,000 to$175,000/acre.

2-41 SR3Q3675

Conclusion

Retain synthetic membrane caps as representative capping process options.Remove soil admixtures, low permeability soils, and asphalt/concrete caps fromfurther consideration.

2. Bottom Sealing

Bottom sealing methods are used to prevent escape of leachate into underlyinggroundwater. The two techniques available are grouting and blockdisplacement. Both techniques form a low permeability barrier around andbeneath the contaminated soil. For the grouting technique, grout is injectedbeneath the contaminated soil layer to form a hydraulic barrier. The grout isinjected either by drilling through the contaminated layer or by horizontaldirectional drilling from the perimeter of the contaminated area. Blockdisplacement involves the construction of a perimeter barrier with injectionof grout or slurry into specially notched boreholes located throughout thesite. Grout or slurry pumping eventually results in displacement of thecontaminated block of earth and formation of a horizontal and perimeterbarrier beneath the contaminated zone.

Effectiveness

Bottom sealing techniques may be an effective way of preventing the escape ofleachate from the contaminated area if a continuous seal can be formed.Determining the integrity of the seal is difficult. Other disadvantages ofbottom sealing are its unproven track record and its inability to preventleachate formation.

Bottom sealing would reduce the mobility of contaminants into the groundwater,providing a degree of protection for human health and the environment. Thereis a chance that a complete seal would not be formed or that leaks woulddevelop, and therefore, the ability of bottom sealing techniques to meet theremediation goals identified in the remedial objective is not certain.

2-42 flR303676

Implementability

! Bottom sealing techniques would require drilling a series of boreholes acrossthe contaminated soil areas and injecting grout to form a horizontal barrier.

: Implementation for the grouting and block displacement techniques is similar

except that with block displacement the grout injection is continued until thej contaminated block is displaced and a bottom seal is formed beneath the block.

I Because bottom sealing techniques are in a developmental stage, no detailedanalysis of applications, limitations, design, or construction considerations

I is yet possible (EPA, 1985b). There are no known case histories where thistechnology has been applied at Superfund sites.

I Cost

I Cost estimates for bottom sealing methods are not currently available.

Conclusion

Because bottom sealing of contaminated soil has not been demonstrated atSuperfund sites, bottom sealing techniques will be eliminated from furtherconsideration.

3. Excavation and Disposal

Excavation and disposal involves the excavation of contaminated soils anddisposal in a lined RCRA-approved hazardous waste landfill. Disposal caneither be in a lined landfill onsite or via shipment to an offsite landfill.The RCRA Land Disposal Restrictions recently promulgated by EPA will probablyimpact any alternatives that include excavation and disposal by requiringspecific levels of treatment for the soil or debris prior to placement in alandfill.

flR303677

Effectiveness

Excavation and disposal can provide a degree of protection to human health andthe environment since the contaminated soils are transferred to a more securelocation with less likelihood of groundwater contamination. The toxicity orvolume of the contaminants in the soil would not be reduced. The reliabilityof the disposal facility would be monitored through routine inspection andmaintenance, groundwater monitoring, and a leak detection system.

Implementability

The major challenge to excavation is controlling the release of contaminatedparticulates and VOCs into the atmosphere during excavation. A pilot-scalestudy at the McKin Superfund Site utilized caisson digging to enclose the soilduring excavation (Webster, 1986). However, this method would beprohibitively expensive for full-scale remediation of the deep soils at theHeleva Landfill Site. Other measures to prevent the release of contaminantsinto the air include covering of exposed contaminated soils and suppression ofdust through spraying with water and/or a chemical suppressant during dryweather periods. Proper respiratory and dermal protection for site workerswould be required. Air monitoring would be useful to determine the potentialfor exposures to site workers and the community.

As contaminated soils are excavated, they should be transferred to trucks withscalable containers or to a temporary storage area, preferably a diked orbermed area lined with plastic or low permeability clay. A layer of absorbentmaterial should be placed on the bottom of the temporary storage area. Gasanalyzers would be used to determine the approximate level of contamination of

soils. Soils could then be segregated based on contaminant levels (EPA,1985).

Open pit excavation methods would likely destroy a portion of the existinglandfill cap. A suitable area at the existing landfill is not available forconstructing an onsite RCRA-approved landfill for the excavated soil.

2-44 ^303678

II

II

Cost

The cost of excavation and offsite disposal was estimated to range between$125 and $745 per cubic yard, depending on the depth of excavation andavailability of a disposal facility.

Conclusion

The difficulties associated with excavating and disposing of the contaminatedsoils are several. Considerable public health risks would be associated with

this option due to potential exposures of site workers during excavation, andof the general public due to potential spillage during transportation. Thenormal limit of excavation equipment is approximately 25 feet, but soil

contamination extends to over 70 feet deep. Reaching greater depths wouldrequire large open pit excavation methods with terraced side slopes. Open pitexcavation would destroy a portion of the cap over the landfill area, adding

additional cost to this option. For these reasons, excavation and disposalhas been screened from further consideration.

2.4.4 Treatment

The treatment-based remedial technologies that were initially considered to bethe most compatible with the nature of contamination at the Heleva Landfill

Site were thermal, vapor recovery, fluid extraction, biological, and soildewatering technologies. Since thermal, fluid extraction, and biologicaltechnologies were screened out in the Evaluation of Source ControlTechnologies. Heleva Landfill Site report, the individual process options forthese technologies will not be discussed in detail. An evaluation of thetreatment-based technologies is summarized below.

2.4.4.1 Thermal Treatment

Two types of thermal treatment processes are available for VOC-contaminatedsoils: high temperature incineration and low temperature desorption. In high

temperature incineration, the organic material is oxidized into combustion

2-45 SR303679

products of carbon dioxide, carbon monoxide, hydrogen chloride, and water. In

low temperature desorption, the organic material is volatilized from the soiland entrained in the flue gas stream. Oxidation or destruction of theentrained vapors is accomplished in a separate chamber away from the soil.

Three types of thermal treatment systems were reviewed. The most widely usedthermal treatment technology utilizes the rotary kiln (EPA, 1988c). Long used

for hazardous waste incineration at fixed-base facilities, it was adaptedearly as mobile/transportable units in the field. Another option availablefor thermal processing of contaminated soils uses bed technology as refined ina circulating bed combustor (CBC). The soil fed into the unit becomesfluidized in extended contact with the sand bed which efficiently transfersheat to the soil and oxidizes any organics present. A third, more recenttechnology that has seen increasing use in the cleanup of hazardous wastesites is the infrared (IR) incinerator or IR furnace. The IR furnace usessilicon carbide elements to generate thermal radiation in the infraredspectrum. High or low temperature processes can be achieved by either systemif properly designed.

Effectiveness

Thermal treatment technologies are capable of destroying all of the organiccompounds found in contaminated soil at the Heleva Landfill Site and,therefore, could effectively meet the remediation goals identified in theremedial action objective. These technologies would permanently remove thetoxicity from the contaminated soil and provide a high degree of protectionfor human health and the environment.

Process capacities vary with the types of systems described above. Fixed-basefacility rotary kilns and at least one transportable kiln can have capacitiesof up to 20 tons/hr (EPA, 1988c). Most mobile/transportable units have lower

capacities. While obviously dependent on physical size and operatingconditions, mobile/transportable kilns, CBCs and IR furnaces can all processfour to six tons/hr of contaminated soils (EPA, 1988c). Considering the

2-46 0R303680

amount of soils at the Heleva Landfill Site above the remediation goals, itwould take approximately two to three years to process the soil with two20-tons/hr units (i.e., 50,000 tons/yr/unit).

Implementability

Soil processing by fixed-base facilities involves only the rotary kiln processoption. No fixed-base commercial CBC or IR hazardous waste facilities exist.Even with rotary kilns, adequate capacity is questionable. Transportation of

large amounts of soil to a fixed-base facility and the return of thedecontaminated soil would require a considerable number of trucks. Costs,scheduling, and availability of trucks for this type of operation all presentchallenges.

IMobile/transportable units are more readily available for cleanup operations.

I Kilns, CBCs and IR furnaces have all been tested and operated at hazardouswaste cleanup sites. The largest number of mobile units are rotary kilns,followed by IR furnace units. Only one company markets transportable CBC

units. All mobile units would require utility hookups for electricity, fuel,and water. Liquid discharge connections may be required depending on flue gascleaning system selection. Chemical usage will also depend on the off-gascleaning system.

One area of environmental impact involves solids residues and their disposal.Processed material from a high temperature kiln could be solidified slag orglass-like "melted" soil. A low temperature kiln discharge would be cleansoil with some possible glassification occurring. This type of residue wouldalso be expected from a CBC or IR furnace, and should be satisfactory fordisposal back on the Heleva Landfill Site.

Another waste stream generated during the thermal treatment processes comesfrom the flue gas cleaning system. The type of flue gas cleaning systemdepends on the selected technology. The CBC, which uses lime or limestone inthe combustion chamber to remove acid gas constituents, requires only

2-47 flR30368!

particulate collection devices on its effluent gas stream. Kilns and IRfurnaces would require some form of gas scrubbing equipment to remove acid gascomponents, in addition to particulate removal devices. C tench vessels andscrubbers clean flue gas by means of aqueous-based chemical reactions. Theresulting liquid waste streams are characterized by high salt concentrationsand low pH, generally unacceptable for direct discharge to surface waters, asewer system, or groundwater reinjection.

Excavation of the contaminated soil would be a major logistical problem forany thermal system. All of the thermal treatment systems depend on the soilsbeing removed, processed to some degree, fed to the system, and replaced ordisposed of offsite. The contaminated soil has a large surface area and apotential depth of excavation of over 70 feet. Substantial equipment andmanpower would be required for such a large site. The existing cap over thecontaminated soil areas would need to be removed prior to excavating the

soils.

Excavation and handling of the contaminated soil would also presentpotentially serious health risks to site workers and the local community. Thethermal processes require varying degrees of pre-feed material handling whichmay expose workers to chemicals contained in the soil. Proper respiratoryprotection would be required. The excavation process, especially consideringthe required depth of excavation, would be a source of hazardous emissions tosite workers. In addition, the excavation would generate dust and fugitiveemissions to the surrounding area which are difficult to control.

Thermal treatment costs are highly site specific. Variables affecting thecost include quantities of soil, heat content, debris content, and moisturecontent. However, all three process types have a similar cost range of $100to $400/ton (EPA, 1985b, 1988c).

2-48

Conclusion

Although thermal treatment technologies are reliable and permanent methods of

soil treatment, the logistical requirements of implementing these technologiesat the Heleva Landfill Site are prohibitive. The major problem for thermaltreatment is the large amount of excavation required before the soil can be

treated, and the associated public health risks to site workers and thecommunity during the excavation. The limited available capacity of mobile and

1 fixed-base systems would also probably result in a prolonged cleanup effort.

* For these reasons, thermal technologies will not be retained as aI representative technology in this FS.

2.4.4.2 Vapor Recovery Treatment

Vapor recovery systems can reduce VOC contamination from the subsurface by

I removing the contaminated soil gas and lowering the partial pressure of VOCsin the void spaces of the soil, causing dissolved and adsorbed constituents to

1^^ volatilize. The volatilization process is continued until the remedial

^BF objectives for soil cleanup have been attained. The vapor recovery system_ process options under consideration are soil venting, vacuum extraction, steamI stripping, and radio frequency (RF) heating.

I 1. Soil Venting

Passive soil venting involves the placement of screened wells or permeabletrenches in the vadose zone of the contaminated soil. Wells and trenches are

j backfilled with crushed stone and impermeable seals are constructed near thesurface to minimize the infiltration of surface water. The depth of the wellsor trenches should extend to a relatively impermeable stratum of bedrock or

I| clay, or to the seasonal low groundwater level (EPA, 1985b).

Effectiveness

j Passive soil venting systems are expected to remove only compounds that arehighly volatile under ambient conditions. In addition, passive systems will

2_49 HR3Q3683

remove gases under pressure such as methane resulting from biodegradation oforganics in a landfill environment. Whereas passive vents may performeffectively at some sites, this method cannot be considered reliable for soilgas migration control because of the inability of vents to control diffuseflow (EPA, 1985b). Gases moving by diffusion tend to move randomly in alldirections from a point of high concentration (i.e., a spill area), as opposedto convection that causes gases to flow in the direction of the steepestpressure gradient. There are no known case histories where this technologyhas been applied at Superfund sites for the purpose of soil cleanup.

This process option would not be expected to meet the remediation goalsidentified in the remedial action objective.

Implementability

By design, passive soil venting is the simplest process considered and has fewlogistical requirements. The logistics of excavating open trenches (i.e.,bracing or sloping trench walls) can constrain the use of passive ventingtrenches to relatively shallow depths of 30 feet and less (EPA, 1985b).Backfill material should be rounded gravel or crushed stone. Three- orfour-inch PVC pipe is customarily used for screen and riser pipe.

If impermeable barriers are installed, a synthetic membrane will need to bespliced in the field. Venting wells and trenches should terminate at thesurface with a V-shaped standpipe. Treatment of vapors may be impracticalbecause of the head loss across treatment columns.

Cost

The estimated cost for a perimeter trench 30 feet deep with vent pipes spacedon 50-foot centers is $132 to $238/linear foot of trench (EPA, 1985b).

Conclusion

Passive soil venting will not be retained as a representative process optionin this FS.

J5R30368U

2. Vacuum Extraction

This process involves the installation of wells that are screened through thecontaminated soil zones. The wellheads are manifolded to a common point where

a vacuum is applied and vapors are treated. Designs can be flexible to meetsite-specific conditions. Wells can be brought on-line at different times to

| allow time for liquid and gas diffusion and to change air flow patterns in theregion being vented (Hutzler, et al., 1989). Extraction wells can be

! converted to passive air intake or air injection wells to promote horizontalsubsurface vapor flow. An impermeable surface cap will also change the air

flow pathways so that clean air is more likely to come from air vents orI injection wells rather than the surface. This will also extend the radius of

influence around a well.

\Effectiveness

* Vacuum extraction systems have been used to treat contaminants in soil similar_ to those detected at the Heleva Landfill Site, including acetone, DCE, TCE,^^V tetrachloroethene, toluene, ethylbenzene, and xylenes (i.e., Malmanis, et al.,

1989). The effectiveness of vacuum extraction is limited by the airI permeability and moisture content of soils. The tight silt and clay soils at

the Heleva Landfill Site would yield a small radius of influence for vacuumI wells and therefore a large number of wells would be required to cover the

contaminated area, A properly designed vacuum extraction system would meet• the remediation goals identified in the remedial action objective for all• contaminants except those which are highly water soluble and do not readily( v o l a t i l i z e from soil moisture (e.g., acetone and 2-butanone). This process

option would yield a reduction of toxicity in the contaminated soils andprovide a degree of protection of human health and the environment.

IThe feasibility and preliminary design of a vacuum extraction system for the

I Heleva Landfill Site was evaluated through an onsite pilot-scale treatabilitystudy. This treatability study is discussed under the detailed analysis ofalternatives in Chapter 4 and in Appendices D and E.

2-51 flR303685

Implementab i1i ty

Spacing between wells is a critical factor in the vacuum extraction systemdesign (EPA, 1985b). A phased installation or pilot testing is generallyrequired to determine the radius of influence of the pressure gradient and theextraction rates. Well spacings are then determined such that the radius ofinfluence of adjacent wells are slightly overlapped. The most cost-effectivecombination of flow rater vacuum pressure, and well spacing is selected forsystem design (EPA, 1985b).

Site clearing and grubbing may be necessary to provide clear pathways formanifold piping. Temporary buildings would be needed to house the vacuumblowers and treatment processes. Treatment of vapors typically consists ofliquid-gas separators and vapor-phase activated carbon. The vapor-phaseactivated carbon may be regenerated onsite if a steam plant is provided.Water from the liquid-gas separators and carbon regeneration is generallytreated onsite with catalytic oxidation or liquid-phase activated carbon.Final disposal would then be required for the treated water (i.e., publiclyowned treatment works [POTW], surface waters, or groundwater reinjection).Spent liquid-phase activated carbon is normally treated and disposed ofoffsite. Adequate sources of electrical power, water, and activated carbonwould need to be provided.

Laboratory analysis of well headspace vapors, direct soil sampling, andpossibly other means would be required to monitor the removal of contaminants.

Mobile laboratories can be outfitted to provide these services onsite.

There are an increasing number of firms that specialize in vacuum extraction.

In addition, the design of these systems has been performed by severalfull-service engineering consulting firms.

RR3036862-52

I

Cost

The cost estimate developed under the EPA's Superfund Innovative TechnologyEvaluation (SITE) program for vacuum extraction technology was $50/ton oftreated soil (EPA, 1989b). The onsite treatability study determined thatcosts may range from $10 to $75/ton of treated soil (or $17 to $108/cubic

yard) depending on the depth of contamination and the effective airpermeability of the soil (refer to Appendix D for cost estimate).

Conclusion

Vacuum extraction will be retained as a representative process option for

further consideration.

* 3. Steam Stripping

This technology has been designed for both continuous and batch treatmentoperations. In the continuous mode, steam injection pipes are placed into the

soil beneath the contamination zone. A vacuum is applied to the underside ofan impermeable surface cap or to screened wells to bring contaminated vapor to

the surface for treatment. A batch process involves the use of modifieddrilling equipment to inject steam and collect vapors under vacuum from the

contaminated soil.

Effectiveness

This method uses steam to increase the temperature of the contaminated soil

and to enhance the volatilization rate of organic compounds. Steam iscontinuously injected into the soil, and recovery wells collect bothcontaminated vapor and liquids for treatment. The high temperature steampromotes the mobility of semivolatile compounds and nonaqueous phase liquids.

The technical reliability of in-situ steam stripping is not as well proven asvacuum extraction. Currently, there are no known case histories where steamstripping has been used in a full-scale remediation of a Superfund site.

2-53 flR303687

This process option of vapor recovery treatment would be expected to meet theremediation goals identified in the remedial action objective. The removal ofcontaminated soil moisture with the rising steam would be expected to removewater soluble contaminants such as acetone and 2-butanone from the soil. Thereduction of toxicity by decontaminating the soil would provide a degree ofprotection for human health and the environment.

Implementability

Treatment of vapors and water would likely involve activated carbon, asdescribed under vacuum extraction. A combined in-situ steam stripping andvacuum extraction system would involve locating a number of stainless steel

injection wells within the radius of influence of vacuum extraction wells.Onsite steam generation, electricity, and water would be required.

In-situ steam stripping is an emerging technology with only a limited amountof field testing; only two firms that specialize in this technology wereidentified.

Cost

The estimated range of costs for performing steam stripping in a batchoperation (i.e., through modified drilling augers) is $75 to $150/cubic yardof treated soil (Williams, 1989).

Conclusion

Since steam stripping has the potential to remove all of the contaminantsidentified in the remedial action objective, it will be retained as arepresentative process option for further consideration.

4. Radio Frequency Heating

This technology involves transmitting RF energy to the ground throughelectrodes placed either horizontally above the ground surface or down aborehole, causing dipolar molecules to vibrate and rotate, and thereby

2-54 flR303688

Iconverting electromagnetic energy to heat. As the temperature of the soilincreases, low boiling point hydrocarbons are volatilized or stripped from thesoil by rising steam. At higher temperatures, vaporization or pyrolysis of

organics will occur. Contaminated vapors are collected under a surfacebarrier and treated.

Effectiveness

j The RF heating process was originally developed in the mid-1970s forI recovering hydrocarbon-based resources from oil shale and tar sand deposits._ In pilot-scale soil remediation studies, it has been shown that by heating

I soil to about 160°C, up to 99 percent of VOCs can be removed.

1 RF heating is an emerging technology, and currently there are no known case

histories where this technology has . been applied for the full-scaleI remediation of Superfund sites. Therefore, it has not yet been proven that RF

heating is capable of treating the volume of contaminated soil or meeting theremediation goals identified in the remedial action objective for the HelevaLandfill Site.

Implementab i1i tv

This technology involves placing electrodes on the surface of contaminatedsoils or down boreholes and providing energy through RF generators operatingbetween 2 and 45 megahertz. A vapor barrier of prefabricated metal or anair-inflatable structure is placed over the electrodes to collect both gasesand liquid condensate. RF radiation emitted upward by the electrodes isgrounded by a wire mesh surface. In a conceptual installation, the structurewould enclose 10 rows of copper-clad, steel pipe electrodes per acre, witheach row being 209 feet long (Hazardous Waste Consultant, May/June 1988).Vapor and liquid treatment may be similar to that described under vacuumextraction.

RF heating technology is currently licensed to one firm and is not yetcommercially available. The overall technical feasibility and long-term O&Mrequirements of this technology are currently unknown.

2_55 UR303689

Cost

Pilot-scale studies had a cost range of $30 to $58/ton of treated soil (Dev,et al., 1988).

Conclusion

RF heating will not be retained as a representative process option in this FS,since it is an unproven technology and other options that have proven to beeffective are available.

2.4.4.3 Fluid Extraction Treatment

A number of fluid extraction technologies are available. Some of thetechnologies that may be used include: soil washing/soil flushing, BasicExtraction Sludge Treatment Process (B.E.S.T.), supercritical fluid extraction(SCF), and alkaline polyethylene glycol (APEG) systems. Soil washing/soilflushing is considered to be the most appropriate fluid extraction technologyfor the organic contaminants at the Heleva Landfill Site. The other fluidextraction technologies (B.E.S.T. for oily soils; SCF for PCBs, DOT, andtoxaphene; and APEG for PCBs) are not considered applicable at this time andhave been screened from further consideration.

Effectiveness

A number of bench- and full-scale tests of the soil washing process have been

performed on soils contaminated with VOCs, PCBs, oil and grease, halogenatedhydrocarbonsr phenols, and aromatics. A bench-scale study (Frost, 1989)showed removals of VOCs up to 99.9+ percent. Vendors claim that five tons oftreatment residues are generated per hundred tons of soil treated (EPA,1988e). An assessment of soil washing systems in the Netherlands and in the

Federal Republic of Germany showed 90 to 95 percent removal efficiencies for awide variety of organics (EPA, 1988e).

2-56

In-situ soil flushing is both innovative and contaminant-specific. It has thegreatest potential for success in soils contaminated with only a few chemicals

I

i due to great difficulty in finding a suitable formulation of washing fluidthat can be applied to contaminants having different properties. This

technology has been used for removal of VOCs from permeable soils (EPA,

1988e).

The very fine particle size of the soils at the Heleva Landfill Site could

present problems in terms of contacting the contaminants with a flushing' solution and separating the contaminants from the soil matrix. Soil washing

I fractionates the coarse soils from the fine-grained soils and the contaminants

normally cannot be removed from the fine-grained fraction. Since the majorityof contaminated soils at the Heleva Landfill Site are fine-grained silts and

I clays, soil washing would not be expected to be an effective means of reducing

the volume of contaminated soils. The low permeability of the soils wouldI also impede the effectiveness of in-situ soil flushing. Therefore, it is not

expected that soil washing/flushing technologies would be capable of meetingthe remediation goals identified in the remedial action objective.II

IImplementability

As discussed under the thermal technology section, the excavation of soil forsoil washing treatment would create significant engineering challenges andhealth and safety concerns. A large area would need to be excavated to depthsof up to 70 feet. Part of the existing landfill cap that covers contaminatedsoil would need to be removed. Contaminated vapors and dust would be

difficult to control, posing risks to site workers and possibly the localcommunity.

A staging area would be required to prepare the excavated soil for furthertreatment. A processing area (solvent wash area) would be needed where thesoil is treated and the solution containing the contaminants is cleaned andrecycled for reuse. Any waste stream containing the contaminants extractedfrom the soil would need to be further treated at the processing area and/ordisposed of appropriately. The treated soil may be used to backfill theexcavated area. Since there is a good possibility that there may be some

2-57 RR30369I

residual contamination in the soil following treatment, the Land DisposalRestrictions for certain RCRA hazardous wastes would need to be evaluated.

For in-situ soil flushing, an injection trench or injection wells are neededto deliver the flushing solution and extraction/recovery wells to pump thegroundwater. A processing area is required for flushing solution preparation,treatment of the solution for recycling and reuse, and any further treatmentneeded for residuals generated by the separation process. Due to the lowpermeability overburden soils and the unconfined aquifer beneath the HelevaLandfill Site, it may not be technically feasible to thoroughly flush thecontaminated soil and recover much of the flushing solution from thegroundwater. The potential exists for spreading the contamination furtherinto the soil and groundwater.

Cost

An EPA review of soil washing installations in the Netherlands and Germanyfound costs to range from $90 to $155 per ton of treated soil (EPA, 1988e) .Unit costs for soil flushing are not currently available.

Conclusion

Soil washing and soil flushing will not be further considered as appropriate

remedial technologies for the Heleva Landfill Site.

2.4.4.4 Biological Treatment

Biological treatment technologies have been well developed for treatingaqueous waste streams contaminated with nonhalogenated organics and some

halogenated organics, whereas bioremediation technologies for treatingcontaminated soil are still emerging. Currently, there are three types ofbiological processes available for treating soil. These are in-situbiodegradation, solid-phase bioremediation, and slurry-phase (liquid/solid)bioremediation.

2.58 /JK303692

E ffe c t ivene s s

In general, under aerobic conditions, hydrocarbons, light petroleumdistillates, and aromatic hydrocarbons (including benzene, toluene, xylenes,ethylbenzene, and naphthalene) are biodegradable. The rate of degradationdecreases with increasing molecular weight (i.e., long chain, cyclic, andpolyaromatic hydrocarbons) and decreasing solubility. Chlorinatedhydrocarbons (such as DCE, TCE, and tetrachloroethene) are not readilydegraded aerobically. Biodegradation of these chemicals becomes increasingly

difficult with the degree of chlorine substitution. In addition, high removalefficiencies of many volatile materials which are known to be biodegradablemay be a result of volatilization instead of biodegradation (Brubaker, 1989;

Loehr, 1989). Research has shown that chlorinated hydrocarbons may bedegraded aerobically by cometabolism or induction of enzymes through anaromatic pathway. Under anaerobic conditions, chlorinated hydrocarbon

compounds can be dechlorinated, but this process may create toxic byproducts" such as vinyl chloride.

VIn order to achieve biodegradation, nutrients and oxygen must be transportedthrough the soil. This is particularly difficult at sites where the geology

is highly irregular, or where there are low permeability soils such as siltand clay. Under the difficult conditions present at the Heleva Landfill Site,particularly the low permeability soil and the depth of contamination, it isnot expected that biological treatment would attain the remediation goalsidentified in the remedial action objective.

Implementation

The solid-phase and slurry-phase process options both require excavation ofthe contaminated soil prior to treatment. In-situ bioremediation requires theinjection of microorganisms, nutrients, and oxygen into the surface soil andrecovery of contaminants flushed into the groundwater. As discussed underother technologies, the excavation of the deep soils or the injection offluids into the low permeability soils of the Heleva Landfill Site presentsconsiderable engineering and health and safety problems. The overalltechnical feasibility of using biological treatment at the Heleva Landfill

Site is considered low.

2-59 SR303693

Cost

Under suitable conditions, the cost of bioremediation processes ranges from$50 to $200 per cubic yard of treated soil (Bourquin, 1989).

Conclusion

Biological treatment will not be retained, as an appropriate technology forconsideration in this FS, due to the low permeability of soils on site and theextremely high concentrations of contaminants which would most likely be toxic

to microorganisms.

2.4.4.5 Soil Dewatering and Treatment

Soil dewatering is being considered as a means to remove soluble contaminantsfrom the saturated soil above the bedrock. Dewatering of the soil will lower

the water table elevation and may also be combined with unsaturated soiltreatment technologies later on as a. remedial alternative for treating thiscontaminated soil layer. Two scenarios for soil dewatering have beenconsidered: wells screened in the saturated soil zone above bedrock, andwells advanced a short distance into the bedrock. Since the equipment andimplementation of these two scenarios are similar, they will not be discussedindividually. The groundwater pumped to the surface is treated byconventional water treatment methods such as activated carbon or activatedsludge.

Effectiveness

Soil dewatering will decrease the amount of contamination in the saturatedsoils and cause a reduction in the migration of contaminants to thegroundwater. Removal of overburden groundwater will also allow remediation ofcontamination in the soils by other processes (i.e., vapor extraction). Inaddition, water soluble contaminants that cannot be removed by vaporextraction (e.g., acetone and 2-butanone) will be recovered along with theoverburden groundwater.

2-60 AR3036914

The degree of protection of human health and the environment, as well as the

reduction in toxicity of the soils, are dependent upon the effectiveness of aparticular soil dewatering process to remove contaminated groundwater from thesoils. The low permeability and depth of contaminated soils at the Heleva

Landfill Site present significant challenges to designing an effective soildewatering system.

Implementability

* Overburden soil dewatering would involve the placement of either

I large-diameter, small-diameter, or open-hole shallow bedrock wells. Large-diameter extraction wells are typically used by dewatering contractors inareas where the transmissivity is low and the depth to groundwater is deep

I (i.e., greater than 20 feet). The diameter of the well casing is not ascritical as the diameter of the gravel pack. Dewatering contractors will

I normally use 3-foot to 4-foot diameter borings packed with highly porous

material. The well screens and casings range in size from 4 to 18 inches.

" j> Small-diameter extraction wells are similar to large-diameter wells with

. regard to construction and materials used. Small-diameter wells typicallyI have 8-inch to 12-inch gravel packs and 4-inch to 6-inch well screens. The

well yield is typically half the rate of a large-diameter well located in theI same strata. The main advantage is that a reduced cost per well allows for a

tighter grid spacing in areas where the water bearing strata areI nonhomogeneous. A tighter grid spacing helps to increase the probability of

removing groundwater from highly localized areas.

* Shallow open-hole bedrock wells would be installed to intersect fractures in. the bedrock. By creating a cone of depression near the top of bedrock, thej overlying saturated soil would be drained of its water over time.

The large- and small-diameter overburden wells would yield considerably lessgroundwater than the shallow bedrock wells. It is estimated that overburden

wells placed in the low permeability soils at the Heleva Landfill Site wouldyield less than 10 galIons/day/well, whereas shallow bedrock wells thatintersect bedrock fractures may yield several thousand gallons/day/well.

2-61 RR303695

Soil dewatering would require an onsite water treatment facility. Since agroundwater treatment facility is currently being designed by the NUS

Corporation for treatment of the bedrock aquifer, it may be possible to treatthe groundwater from soil dewatering at this facility.

Cost

The cost of installing extraction wells under Level B health and safetyconditions is approximately $15,000 per well. The cost of an onsite water

treatment system for about 18 overburden wells would be approximately$150,000.

Conclusion

Since shallow bedrock wells would generate a large quantity of groundwaterand, consequently, require a considerably large water treatment facility, thisprocess option has been screened from further consideration. Large- and

small-diameter overburden extraction wells offer a means of removing watersoluble contaminants from the soil and may be combined with other in-situtechnologies (i.e., vacuum extraction) to remediate the saturated soil layer.Therefore, overburden dewatering wells will be retained as a representativeprocess option for this FS.

2.4.5 Summary of Screening of Technologies and Process Options

The technical evaluations, based on effectiveness, implementability, and cost,

are summarized in Table 2-7 for those technologies and process options thathave passed screening. In this table, the remedial technologies are organizedaccording to the general response actions developed in Section 2.3.Technologies and process options that have been retained for furtherconsideration will be part of the remedial alternatives developed in

Chapter 3.

2-62 1R303696

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RR303698

I3.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES

In this chapter, the general response actions and process options selected torepresent the various technology types will be combined to form remedialalternatives. These alternatives will include no action, containment, andtreatment options. Once the remedial alternatives have been developed, theywill be screened, if necessary, in accordance with 40 CFR Part 300.430, based

on effectiveness, implementability, and cost. The screening may be performedto reduce the number of alternatives to be subjected to the detailed analysisin Section 4.0.

3.1 DEVELOPMENT OF ALTERNATIVES

Based on the general response actions, remedial technologies, andrepresentative process options developed in Section 2.4, six remedialalternatives were developed for the contaminated soils as shown in Table 3-1.

Only combinations of general response actions, technologies, and processoptions considered to be the most rational (based on effectiveness,implementability, and cost) were developed into alternatives. As shown in

1 Table 3-1, the main alternative headings are organized according to the

general response actions.

For the capping alternative (Alternative 2), a cap with a 30-mil LDPEsynthetic membrane was selected as the representative process option since itwould be nearly as effective as a more expensive 60-mil HDPE membrane andwould be easier to install due to its lighter weight.

Four alternatives were developed for treatment. Three limited treatmentalternatives use a combination of soil treatment and containment under theexisting landfill cap or an extension to the existing cap to address theremedial action objective. A fourth full treatment alternative utilizestreatment of the contaminated soil as the principal means of attaining theremedial action objective. Subalternatives are included under the treatment

BR3036993-1

TABLE 3-1

REMEDIAL ALTERNATIVES


AlternativeNumber

1

2

3

3a

3b

4

4a

4b

5

5a

5b

5

6a

6b

Alternative Title

No Action

Containment — Extension of Existing Cap

Limited Treatment of Unsaturated Soil — 34 ug/kg TCEAction Level Outside Existing Cap and 58,600 ug/kg TCEAction Level Inside Existing Cap

Vacuum Extraction


Limited Treatment of All Soil — 58,600 ug/kg TCE ActionT.evel and Extension of Existing Cap

Vacuum Extraction, Soil Dewatering, and Extensionof Existing Cap

In-situ Steam Stripping and Extension of Existing Cap

Limited Treatment of All Soil — 34 ug/kg TCE Action LevelOutside Existing Cap and 58,600 ug/kg TCE Action LevelInside Existing Cap

Vacuum Extraction and Soil Dewatering


Full Treatment of ail Soil — 34 ug/kg TCS Action LevelInside and Outside Existing Cap

Vacuum Extraction and Soil Dewatering


Both

3-2

ialternatives to facilitate comparisons among the technologies and limit thetotal number of alternatives. The presence of the existing landfill cap overa portion of the contaminated soil area warrants the use of different soilcleanup goals for inside and outside the boundary of the cap. Soil cleanupgoals for capped and uncapped soils were presented in Table 2-3. TCE is usedas a representative contaminant, as discussed in Section 2.3.1, to determinesoil cleanup action levels for the various capping and treatment alternatives.

• The vacuum extraction and soil dewatering subalternatives (Alternatives 4a,I 5a, and 6a) have combined these two technologies to address the shortcomings

of using either technology alone. In general, vacuum extraction is anI effective means of removing organic contaminants from the vadose zone if they

have high volatility and low solubility. The high solubility of two siteI contaminants, acetone and 2-butanone, means that these contaminants will be

dissolved in the soil moisture and will not readily volatilize. Vacuum( e x t r a c t i o n is also not effective for treating saturated soils. Soil

dewatering has therefore been added to these subalternatives to allow vacuumextraction to work in the saturated soil layer and as a means to removeacetone and 2-butanone from the soil.

In-situ steam stripping (Alternatives 3b, 4b, 5b, and 6b) is expected to beeffective in both saturated and unsaturated soil layers, and for removing bothhighly volatile and soluble soil contaminants. This is an innovativetechnology, however, and there may not yet be sufficient information toperform all aspects of the detailed analysis in Chapter 4.

Descriptions of the remedial alternatives are given in Section 4.0, DetailedAnalysis of Alternatives, rather than in this section, because no remedialalternatives will be eliminated prior to the detailed analysis.

3,2 SCREENING OF ALTERNATIVES

Typically, in this section of the FS, the list of potential alternativesundergoes screening, based on effectiveness, implementability, and cost, toreduce the list of alternatives that will be subsequently analyzed in detail.

3-3 AR30370!

However, since only a limited number of remedial alternatives were developed

in Section 3.1, a preliminary screening of alternatives in this section is notwarranted. Therefore, in order to streamline the FS and to provide a moreclearly presented evaluation of alternatives, this tier of screening will beeliminated, and all six alternatives will be retained for detailed analysis inSection 4.0.

3-4 SR303702

RR303703

4.0 DETAILED ANALYSIS OF ALTERNATIVES

i 4.1 INTRODUCTION

The remedial alternatives developed in Section 3.0 are described and evaluatedin detail in this section. The detailed analysis of remedial alternativesprovides information needed to facilitate comparison among alternatives aswell as the final selection of a remedial alternative(s). As outlined in the

1 E P A Guidance for Conducting Remedial Investigations and Feasibility StudiesUnder CERCLA (EPA, 1988b) and in accordance with 40 CFR Part 300.430, theremedial alternatives should be evaluated using the following nine criteria:

0 Short-term effectiveness

I ' Long-term effectiveness* Reduction of toxicity, mobility, or volume

I c Implementability

• ' Cost0 Compliance with ARARs

° Overall protection of human health and the environment0 State acceptance0 Community acceptance

II

Of the nine evaluation criteria, however, only the first seven will beevaluated in this report. State and community acceptance criteria will beevaluated in the ROD following the public comment period. Factors to beconsidered for each evaluation criterion are presented in Table 4-1.

Because this FS is focused on soil remediation to prevent additionalcontamination of the groundwater, some of the evaluation criteria,particularly the overall protection of human health and the environment, willbe discussed only in relation to the degree the alternatives achieve thisremedial action objective. The enforcement actions resulting from the 1985ROD are designed to provide the overall protection of human health and theenvironment. The alternatives developed in this FS will not by themselves

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achieve overall protection, but will remediate the source areas ofcontamination and, therefore, allow the groundwater remediation activities toachieve their goals.

4.2 ALTERNATIVE ANALYSIS

4.2.1 Alternative 1; No Action

This alternative is considered in the detailed analysis to provide a baseline

to which the other remedial alternatives can be compared. This alternativeinvolves taking no further action at the Heleva Landfill Site to remove,

remediate, or contain the contaminated soils and groundwater. Enforcementactions in accordance with the 1985 ROD have already taken place or areunderway, including the installation of a RCRA-approved synthetic membrane cap

over the landfill area, extending the public water supply from Ironton toOrmrod, and the design for an onsite treatment facility for contaminatedgroundwaters.

Short-Term Effectiveness

This alternative provides no additional reduction in groundwater contaminationfrom the contaminated soils. Because there are no further remedial actionsinvolved, protection of workers, the community, and the environment duringremedial action is not a consideration.

Long-Term Effectiveness

This alternative provides no additional long-term protection of thegroundwater. Contaminated subsurface soils that are outside the perimeter ofthe landfill cap would continue to contaminate the groundwater.

Reduction of Toxicity. Mobility, or Volume

This alternative does not reduce the toxicity, mobility, or volume of

contaminants in the soils not covered by the existing landfill cap.

4-4

i

I

Implementabi1i tv

No implementation is required for this alternative.

There are no costs associated with this alternative.

Compliance with ARARs

This alternative does not comply with contaminant-specific ARARs since soilsoutside of the landfill cap would continue to contaminate the groundwater

beneath the site.

Location-specific ARARs were not found to be applicable or relevant and

appropriate for remedial activities at the Heleva Landfill Site.

Action-specific ARARs are not applicable to this alternative, because nofurther remedial actions would be taken.

Overall Protection of Human Health and the Environment

This alternative would not reduce the migration of contaminants from soilsoutside the landfill cap that would continue to contaminate the groundwater.

Because contaminated soils are left onsite without treatment, this alternativedoes not fully comply with CERCLA's preference for the utilization oftreatment that permanently reduces the toxicity, mobility, or volume of thecontaminants at the site.

4.2.2 Alternative 2: Containment--Extension of Existing Cap

This alternative involves containment of the contaminated soils under a lowpermeability cap system. For this alternative, a LDPE synthetic membrane capsystem is presented as a representative process option. The 30-mil LDPE capwas recommended instead of a 60-mil HDPE cap because it would be as effectivein limiting infiltration, yet it would be cheaper and easier to implement.

4-5 flR303708

As shown in Figure 4-1, the cap currently installed over the landfill areawould be extended over areas with high soil contamination. The designobjectives would be to minimize the migration of water into the contaminated

soils. The cap would also be designed to promote runoff and drainage tominimize cap erosion and adverse effects to the surrounding environment. Thedesign of the cap would allow for any settling or subsidence so that theintegrity of the cap would be maintained over time.

The representative LDPE cap would have the following components:

* 6 inches of topsoil

• 18 inches of select fill

0 Synthetic drainage layer8 30-mil LDPE synthetic membrane linere Geotextile cushion fabric

6 inches of select fill9 Variable thickness of common fill

This cap design is intended for illustrative purposes only. The actual capdesign would be developed during the remedial design phase. The cap wouldcover an area of approximately 3.5 acres and would be field seamed to theexisting landfill cap with standard field seaming procedures.

Synthetic membrane caps provide a practically impervious barrier wheninstalled according to manufacturers' recommendations. Numerous types ofsynthetic materials are available which encompass a broad range of chemicaland physical properties. A material that is highly resistant to volatileorganics and other destructive chemicals is recommended for the HelevaLandfill Site. The material should also be elastic and/or strong enough tohandle the detrimental effects of subsidence that often occur in areasadjacent to landfills.

Since the area to be capped is adjacent to the existing landfill, it could besubject to the detrimental effects caused by the migration of landfill gases.

Although the spacing of vents would not need to be as frequent as over the

4-6

flH30374-7

existing landfill cap, a modified passive gas collection system would still berequired to allow gas to dissipate.


Protection of groundwater from leaching of the contaminated soils wouldimprove immediately after the installation of the synthetic membrane cap.Dust may be generated during excavation and grading activities, in which casedust control procedures would be required. Perimeter air monitoring may beneeded to determine the appropriate controls to protect the community fromcontaminated dust and vapors during construction.

Workers would be required to wear protective respiratory equipment (i.e., air

purifying or supplied air respirator) during activities where they may beexposed to hazardous materials. Air monitoring could be performed in workareas to monitor the breathing zone if required. Once the onsite remedialactivities begin, installation of the synthetic membrane cap would takeapproximately three months.


With proper maintenance to ensure that the cap remains intact, the risks posedby migration of the soil contaminants into the groundwater would be reduced.Although a potential source of groundwater contamination would remain at thesite, capping would significantly reduce the infiltration rate through thesoils, thereby reducing the leaching of contaminants into the groundwater andbedrock. The infiltration rates would be reduced from 2 in/yr with no cap inplace to approximately 0 0011 in/yr with a synthetic membrane cap. Using theSummers Model to recalculate the soil cleanup goals with a synthetic membranecap, the TCE concentrations in the soil would need to be less than58,600 ug/kg to meet the MCLGs for contaminants in the groundwater. Detailedcalculations are presented in Appendix A.

I1

Reduction of Toxicitv. Mobility, or Volume

Capping would not reduce the toxicity or volume of contaminants in the soilsand does not provide permanent, irreversible treatment. As discussed in the

previous section, capping would substantially reduce the mobility ofcontaminants in the soils by minimizing migration of water through the soils.

Residuals remaining after installation of the cap mainly include thecontaminated soils at the site--approximately 392,000 cubic yards of soilcontaminated above the 34 ug/kg action level for TCE. Other residuals

remaining after remedial activities include decontamination fluids.Contaminated water generated during onsite activities would be collected andtreated either by activated carbon or by the onsite groundwater extraction

treatment facility designed by the NUS Corporation.

Implementabilitv

The technologies proposed for capping, grading, surface water diversion, andinstallation of the gas venting system are all demonstrated and are

commercially available. An underground storage tank located next to the

abandoned building would be removed before extending the cap.

Cost

The detailed cost estimate for this alternative is presented in Appendix B.The total capital cost for an LDPE membrane cap is approximately $550,000.This cost also includes removal of the underground storage tank. Unit costsfor materials and installation were based on manufacturer's information andcosts for installing the existing landfill cap. Annual O&M costs, assumingfour visits per year to inspect the integrity of the cap and mow the site, areestimated to be $23,000 per year. The estimated present worth value of this

alternative is approximately $904,000.

4'9 RR303712


The cap must be designed and constructed to meet the Pennsylvania requirementsand any relevant and appropriate RCRA requirements for final cover andgrading. Placement of a cap over the contaminated soils is intended toachieve the following (per 40 CFR 265.228):

* Provide long-term reduction of migration of liquids through thecapped area.

* Function with minimum maintenance.

• Promote drainage and minimize erosion and abrasion of the cover.

9 Prevent run-on and runoff from damaging the cap.

* Accommodate settling and subsidence so that the cover's integrity ismaintained.

" Have a permeability less than or equal to the permeability of thenatural soils present.

No other action-specific ARARs are applicable to this alternative.

Capping without treatment of contaminated soils would not attaincontaminant-specific ARARs for the groundwater. Based on contaminant modelingwith a synthetic membrane cap in place, soils contaminated above an actionlevel of 58,600 ug/kg of TCE would continue to cause elevated levels ofcontaminants in the groundwater. Therefore, this alternative will not meetthe remedial action objective to protect the groundwater to MCLs or non-zeroMCLGs.



4-10 flR3037!3

OSHA standards (29 CFR Parts 1910, 1926, and 1904), especially standardsgoverning worker safety during hazardous waste operations (29 CFR Part 1910),would have to be followed during all site work.


It is expected that this alternative would not reduce the migration of

contaminants from the soil to the groundwater and meet the remedial actionobjective for soils since contamination greater than 58,600 ug/kg of TCE wouldremain onsite. Because contaminated soils are contained without treatment,

J t h i s alternative does not comply fully with one of the goals of CERCLA toutilize treatment that permanently reduces the volume, toxicity, or mobilityof the contaminants at the site.

4.2.3 Alternative 3: Limited Treatment of Unsaturated Soil--34 ugAg TCEI Action Level Outside Existing Cap and 58.600 ug/kg TCE Action Level

Inside Existing Cap

4.2.3.1 Alternative 3a: Vacuum Extraction

Based on the results of the Evaluation of Source Control Technologies(Gannett Fleming, 1989c) report, vacuum extraction was recommended as the bestavailable technology for the Heleva Landfill Site, but warranted a. pilot-scalestudy due to the difficult soil conditions. In February, 1990, following thePhase II field investigation activities, an onsite treatability study wasconducted by VAPEX Environmental Technologies, Inc. The final report for thetreatability study is presented in Appendices D and E. A summary of thesystem layout, main results, and conclusions is presented below.

A nested extraction well and several vapor probe monitoring wells wereinstalled approximately 50 feet south of GBH25, near the edge of contaminated

soils in the Abandoned Building Spill Area. Three distinguishable soil unitswere identified at the test location: a soft sandy silt unit extending to adepth of approximately 20 feet, a discontinuous five-foot-thick sand unit at adepth of between 20 feet and 25 feet, and a stiff silt unit extending from adepth of 25 feet to below the water table level (approximately 50 feet). Due

4-11 HR3037U

to the discontinuous nature of the intermediate lens and the recorded perchedwater at this level, the pilot test system was implemented and the site wasmodeled as a two-layer system with an intermediate boundary or lens. The deepextraction well (designated VW-D) was installed with a 15-foot screenedsection extending from a depth of 30 feet to 45 feet below ground surface

(BGS). The shallow extraction well (designated VW-S) was installed with a13-foot screened section extending from a depth of 5 feet to 18 feet. Theannular space around each well was backfilled with silica sand which extendedone foot above and below each screened interval, and an approximately10-foot-thick bentonite seal was installed between the two well screens toisolate the two wells from each other and from the sandy layer at the 20-foot

to 25-foot depth interval. A total of 13 vapor probes were installed in fourboreholes in the vicinity of the vacuum wells to monitor vacuum pressures and

obtain soil gas samples.

Relatively high concentrations of VOCs were detected in each VW-S dischargevapor sample analyzed throughout the duration of the test. The total target

VOC concentrations ranged from a maximum of 11,787 ppm (v/v) on the fifth dayof the test, to a minimum of 3,082 ppm on the ninth (final) day of the test.The primary constituent in each VW-S wellhead discharge vapor sample was TCE,

which ranged in concentration from a maximum of 7,318 ppm on Day 5, to aminimum of 2,474 ppm on the final day of the test. The other prominent targetVOCs and their maximum and minimum concentrations were: cis-DCE ranging from1,760 ppm to 266 ppm; total xylenes ranging from 1,173 ppm to 192 ppm;trichloroethane (TCA) ranging from 661 ppm to 102 ppm; chloroform ranging from517 ppm to nondetected; and ethylbenzene ranging from 292 ppm to 49 ppm.

Tetrachloroethene (PCE) was detected at concentrations ranging from a maximumof 27 ppm to a minimum of nondetectable in several samples, Toluene wasdetected at a maximum concentration of 67 ppm during the initial days of thetest and was detected in only three samples after the second day ofoperations. Vinyl chloride was detected in samples analyzed at an offsite

laboratory at concentrations ranging from 393 ppm on the first day of testingto below detection limits (i.e., <0.10 ppm) on the eighth day of testing.

4-12 3R3Q37I5

In the deep extraction well, the total target VOC concentrations ranged from amaximum of 9,072 ppm at the start of the test to a minimum of 4,073 ppm at the

completion of the test. The primary constituent in each VW-D wellheaddischarge vapor sample was TCE which ranged in concentration from a maximum of7,374 ppm to a minimum of 2,773 ppm. The other prominent target VOCs and

their maximum and minimum concentrations were: cis-DCE ranging from 1,246 ppmto 514 ppm; chloroform ranging from 404 ppm to 203 ppm; TCA ranging from

' 266 ppm to 160 ppm; total xylenes ranging from 231 ppm to 88 ppm; and• ethylbenzene ranging from 59 ppm to nondetectable. PCE was detected atI concentrations ranging from a maximum of 14 ppm to a minimum of nondetectable

in several samples. Toluene was detected in only two samples atj concentrations of 101 ppm and 62 ppm. Vinyl chloride was not detected in the

VW-D discharge vapor samples.

I

INeither acetone nor 2-butanone was detected in the soil gas discharge fromVW-S and VW-D over the duration of the pilot test by the gas chromatograph/

photoionization detector (GC/PID) analysis. Although both acetone and2-butanone were detected in soil samples (2-butanone being present at levelsbelow the specified cleanup limits), their absence from the soil gas would not

be unexpected. Acetone is miscible with water and 2-butanone has a solubility

in water of 353 grams per liter (at 10"c). This is reflected in the extremelylow Henry's constant of both compounds of 3.97 x 10"5 atm • m^/mol (at 25°C)and 4.66 x 10*5 atm • m^/mol (at 25°C) , respectively. Based on thesephysical/chemical properties, it would be expected that unless present in free

phase, both acetone and 2-butanone would be absent as contaminants in the soilgas phase. Accordingly, removal of acetone and 2-butanone, where present in anon free-phase form, would require the application of groundwater extractionand treatment techniques.

Over the duration of the shallow zone pilot test, the total VOC removal rate

ranged from approximately 70 pounds per day at the beginning of the test to20 pounds per day at the end of the test, at an average flow rate of 13 cfmand vacuum pressures between 17 inches and 21 inches of water. During the10-day pilot test, approximately 450 pounds of total VOCs (predominately TCE)

was removed from the shallow soil zone. The shallow vacuum extraction wellhad an effective radius of vacuum influence of approximately 50 feet at the

aR303716

assumed design air flow rate of 100 cfm. In the deep extraction well, thetotal VOC removal rate ranged from approximately 20 pounds per day at thebeginning of the test to 10 pounds per day at the end of the test, at air flowrates of 5 cfm to 5.5 cfm and vacuum levels ranging from 9.1 inches to9.5 inches of mercury. A total of 50 pounds of VOCs were removed over thefour-day test period. In the study area, the deep vacuum extraction well hadan effective radius of vacuum influence of approximately 8 feet to 10 feet atthe assumed design air flow rate of 7 efm. An effective radius of influenceof 10 feet to 12 feet under air injection conditions is assumed at airinjection rates of up to 70 cfm.

The conceptual full-scale vapor extraction system for the shallow soil zoneshould consist of nested vertical extraction wells installed to a 25-foot

depth spaced at 100-foot centers. A total extraction air flow rate of 100 cfmper well would be required at an expected operating vacuum of 15 inches ofmercury.

The conceptual full-scale vapor extraction system for the deep zone shouldconsist of vertical extraction wells (nested) screened over an intervalbetween 25 and 45 feet BGS or to within three feet of the water table. Thewells should be spaced 20 feet on center. Each well may be designed to allowoperation under both extraction and injection conditions. A total extractionair flow rate of approximately 7 cfm per well at an anticipated operatingvacuum of approximately 15 inches of mercury would be required. Whereapplicable, an injection air flow rate of approximately 70 cfm at an operatingpressure of 50 psi would be required at each designated air injectionwellpoint.

VAPEX considers that the presence of the 5-foot-thick sand unit encountered at20- to 25-foot depth should not be considered of paramount importance in thereview of the vapor extraction feasibility assessment. Data from the boringlogs and historical records indicate that this unit is discontinuous. Basedon these properties, the intermediate unit is unlikely to be a crucial factorin the design of the full-scale site remediation system.

4-14

I

It is estimated that the time to achieve the cleanup criteria in the soils inthe shallow zone would be approximately 120 days based on the chemicalmodeling in the test area. Based on the uncertainty associated with the

estimation techniques and in consideration of the uncertainty as to the actualquantities and distribution of VOCs in vadose zone soils, a reasonable

estimate for the time to achieve the cleanup criteria in the shallow zone is

one year.

For the deeper unsaturated soil zone, it is estimated that the time to achieve

the cleanup criteria in the soils would be up to 5 years based on the chemicalmodeling in the test area. The remediation time may vary substantially inthose areas within the designated cleanup area where contamination is presentat significantly different levels than those utilized in the modellingprocess, or where soil characteristics are substantially different from thosethat formed the basis for the conceptual design.


There would be little risks to the surrounding community or the environmentduring the implementation of this alternative. Vapor may be generated duringthe drilling and installation of wells. Proper protective respiratoryequipment during these activities would be required. Air monitoring of thework area breathing zone could be performed. During the operation of thevacuum extraction system, contaminated soil gas would be treated to safelevels.

The time estimated for remediating the soils above the water table with vacuumextraction is five years.


Because the focus of this alternative is on unsaturated overburden soils abovethe groundwater level, the remedial action objective would be achieved only inthe vadose zone. Soil contamination in the saturated soil zone would remainat levels greater than the soil cleanup goals. Contaminated saturated soilsthat are not remediated by this alternative may recontaminate the overlying

4-15 flR3037i8

remediated soils through diffusion of VOCs and act as a continuing source ofgroundwater contamination. Prolonged O&M of the vacuum extraction systembeyond five years may be required to prevent possible recontamination of thetreated soils.

Since vacuum extraction is generally not effective for treating VOCs that are

highly water soluble (e.g., acetone), this alternative may not remediate allof the soil contaminants to below the cleanup goals at the site.


Since the contaminants would be removed from the unsaturated zone to levels

that meet the cleanup goals, this alternative reduces the volume and toxicityof contaminated soil. Approximately 126,000 cubic yards of soil(approximately 3,100 pounds of VOCs) would be remediated to below cleanuplevels. Residuals remaining after implementation include soil moisturecollected in the air/water separator, and spent activated carbon. Water wouldbe treated onsite either by activated carbon or by the groundwater extractiontreatment facility designed by NUS, The spent activated carbon would eitherbe regenerated or disposed offsite.

Imp1ementab i1i tv

Vacuum extraction is demonstrated and commercially available. This technologyhas been implemented at numerous commercial and industrial sites, includingSuperfund sites, since 1980. VAPEX has performed a pilot-scale vacuumextraction treatability study at the Heleva Landfill Site, and recommends itas an effective remediation technology for VOC removal at the site.

It is estimated that eight extraction wells spaced on 100-foot centers wouldbe required to achieve vacuum influence over the shallow zone (up to 25 feetdeep) of the remediation area identified in Figure 4-2. For the deeper soilsbetween 25 feet and the top of the water table, approximately 160 extractionwells spaced on 20-foot centers would be required. The extraction air flowrates would be approximately 100 cfm per well in shallow soils and 7 cfm indeeper soils at an operating vacuum of 15 inches of mercury.

1III

4-17

An onsite staging area would be required for storing clean and used carboncanisters. A RCRA-permitted hazardous waste facility must be able to receivethe used carbon canisters if the carbon is not regenerated but rather disposedoffsite.

Cost

The estimated capital cost for Alternative 3a is $4,620,000, including thecost for removing the underground storage tank. The estimated O&M costs are$483,000 per year. The present worth of Alternative 3a is estimated to be$6,800,000. The detailed cost estimate calculation is presented inAppendix B.

Compliance With ARARs

This alternative would remediate unsaturated soils to a level that would beprotective of groundwater quality. However, the saturated overburden soilswould not be remediated and would continue to be a source of groundwatercontamination. Overall, this alternative would not meet contaminant-specificARARs.

Location-specific ARARs were not found to be applicable or relevant andappropriate for remedial activities at the Heleva Landfill Site.

Action-specific ARARs would need to be addressed for air emissions (NESHAPs),offsite transport of spent activated carbon (DOT rules for Hazardous MaterialsTransport and Pennsylvania Hazardous Substance Transportation Regulations) ,disposal (RCRA and the Pennsylvania Solid Waste Management Act), and workersafety (OSHA, TLVs). It is expected that all of the action-specific ARARs canbe met under this alternative.


Because the saturated overburden soils below the influence of the vacuumextraction system are not remediated, they may recontaminate the remediatedoverlying soils through diffusion of VOCs and continue to contaminate the

1R30372I

groundwater. Therefore, the remedial action objective of protecting thegroundwater cannot be achieved. Although some reduction of contaminant volumewould be achieved, it is expected that the contaminated soil would not be

fully remediated and contaminant migration to the groundwater would continue.

4.2.3.2 Alternative 3b: In-situ Steam Stripping

In-situ steam stripping technology is an emerging technology that will beavailable for both continuous and batch treatment operations. As a continuous

system, it is essentially an enhanced vacuum extraction system that includeshot air or steam injection wells within the radius of influence of the vacuumextraction well. As a batch process, steam and hot air are injected through

the bottom of large-diameter augers and are actively mixed with the soilcolumn until the vapor concentrations from the soil are below specifiedcleanup criteria. Developers of both continuous- and batch-mode technologies

are participating in the EPA SITE Demonstration Program. The batch processwill be discussed as a representative process option in this FS, althougheither process may potentially be applicable for remediating the Heleva

Landfill Site.

The batch treatment unit involved in the SITE program consists of atrack-mounted vehicle with, a drilling tower and a treatment train. Thedrilling tower contains two counter-rotating hollow-stem augers, each with amodified 5-foot diameter cutting bit, capable of operating to a 27-foot depth.

Each drill conveys steam supplied by an oil-fired boiler at 450"F and450 psig, and air at approximately 300°F and 250 psig, to the rotatingcutting blades. Both the air and steam serve as carriers to conveycontaminants to the surface. Vapors are collected by vacuum underneath ashroud and processed through a treatment train. In the treatment train, VOCsand water are removed from the vapor by condensation. The condensed water isseparated from the organics by distillation, treated by activated carbon, andsubsequently used as make-up water for a wet cooling tower. Steam is alsoused to regenerate the activated carbon and as a heat source for distillingthe VOCs from the condensed liquified stream (EPA, 1989b).

4-19 flR303722


Treatment is performed on a soil column with a crossectional area ofapproximately 30 square feet. The time to remediate clayey soils to a depthof 12 feet was demonstrated during the SITE testing to be one to six hours,depending on when the contaminant criterion in the soil vapor was reached.The developer estimates that 10 to 15 cubic yards per hour can be remediatedwith this process.

The process is essentially a closed-loop system, so respiratory protection forthe workers is not generally required. Respiratory protection may benecessary during sampling activities, maintenance, or any other time a workermay be directly exposed to the site contaminants. Exposure risks to thecommunity or adverse environmental impact during the remediation are notanticipated.


The migration of contaminants from contaminated vadose zone soils to thegroundwater should no longer be a concern once the remedial action goalsspecified in the remedial action objective have been met. However, thisalternative does not address deeper, saturated soils which would continue tobe a groundwater contamination source. The deeper soils may eventually

recontaminate part of the overlying treated soils through diffusion of VOCs.


This alternative would remove the contaminants from the unsaturated soil layerand condense these into a concentrated organic liquid that could be properly

disposed (i.e., by incineration). This alternative is expected to remove TCEfrom the unsaturated soil as well as Alternative 3a, and be more effective at

removing water-soluble VOCs such as acetone. The treatment is irreversible inthat the treated soils would not cause further contamination; however, thereis a possibility that the untreated saturated soils could eventually

recontaminate part of the overlying treated soils through diffusion of VOCs.

4-20

I

I

Implementab i1i ty

At present, only one unit has been constructed.. Other units capable ofoperating at greater depths than the demonstration unit are under constructionand could be ready with six months' notice, according to the developer.

A large area outside the existing landfill cap, shown in Figure 4-3, wouldneed to be remediated to the action level of 34 ug/kg TCE. The batch in-situ

steam stripping process, which treats approximately 30 square feet in atreatment block, would require approximately 3,700 treatment blocks toremediate the spill areas outside of the cap. A small area under the cap

containing soils with TCE greater than 58,600 ug/kg could be remediated withapproximately 54 treatment blocks. The actual number of treatment blockswould be determined in the field by starting treatment in a known area of

contamination and moving outward until soils that meet the cleanup criteriawere encountered. The time to remediate these areas using two rigs isapproximately five years.

The amount of contaminants removed (approximately 3,200 pounds of VOCs) is thesame as Alternative 3a, except for the additional removal of acetone in the

area outside of the existing landfill cap. The reliability of the technology

will be evaluated through the SITE program demonstration project. Thetreatment train is complex and would require the availability of specializedequipment and skilled workers to maintain.

Effectiveness of the treatment can be continuously monitored by a flameionization detector for total VOCs in the soil vapor. Contaminantconcentrations in the soil can also be measured in pre- and post-treatmentsoil samples to determine the removal efficiency.

Unit costs for treated soil currently range from $125 to $150/cubic yard forthe SITE demonstration project. The developer anticipates that the unittreatment costs for a larger unit would range between $75 and $100/cubic yard.

flR30372l*4-21

II Based on a $100/cubic yard treatment cost, the net present worth for this

alternative is $19,100,000. The cost for removal of the underground storagetank near the abandoned building is estimated to be $10,000 and is included inthis alternative. A detailed cost estimate is presented in Appendix B.


Since this alternative does not treat the saturated soils, the contaminant-specific ARARs would not be met.


Action-specific ARARs would include the CAA regulations for air emissions(NESHAPs), offsite transport of residuals from the treatment process (DOTrules for Hazardous Materials Transport and Pennsylvania Hazardous Substance

Transportation Regulations), disposal (RCRA and the Pennsylvania Solid WasteManagement Act), and worker safety (OSHA, TLVs). There is expected to be nodifficulties in complying with the action-specific ARARs.


This alternative is expected to remediate the unsaturated soils to theremedial action goals but would not affect the saturated overburden soils thatmay continue to contaminate the groundwater. Therefore, the remedial actionobjective cannot be attained with this alternative. Since contaminants wouldbe removed from the unsaturated soil, some overall reduction of soil toxicitywould be achieved, but the migration of contaminants to the groundwater wouldnot be eliminated. More highly contaminated soils would remain beneath theexisting landfill cap, although the migration of contaminants from the capped

soils is expected to be low.

4-23 AR303726

4.2.4 Alternative 4: Limited Treatment of All Soll--58.600 ug/kg TCE

Action Level and Extension of Existing Cap

4.2.4.1 Alternative 4a: Vacuum Extraction, Soil Dewatering, and Extensionof Existing Cap

To comply fully with CERCLA, an alternative should utilize treatment thatpermanently reduces the toxicity, mobility, or volume of the contaminants atthe site. Capping alone (i.e., Alternative 2) could not achieve this goal.Capping with hot spot soil remediation, however, would reduce the source ofcontamination to acceptable levels.

To achieve the soil cleanup goals with a synthetic membrane cap, only the "hot

spots" of contaminated soil with TCE greater than 58,600 ug/kg need to beremediated. There are two major hot spots, one in the vicinity of boreholeGBH01 in the TCE Spill Area, and the other near borehole GBH25 in theAbandoned Building Spill Area. A total of 18 vacuum extraction wells andapproximately 4 dewatering wells are needed. The approximate locations of thevacuum extraction and dewatering wells are depicted in Figure 4-4. A crosssection of the remediation area is shown in Figure 4-5.

Dewatering wells would be installed in the same boreholes as the vacuumextraction wells to drain the saturated soils above bedrock and allow air toflow through the soil to the vacuum extraction wells. The dewatering ratesthrough the low permeability soils are predicted to be extremely low, on theorder of 2.6 gallons/day/well (see Appendix C).

NUS is performing a remedial design for a groundwater extraction and treatmentsystem for the contaminated bedrock aquifer. The recommended system consistsof a source area facility and a downgradient facility. The source areafacility would be located adjacent to the TCE and Abandoned Building spillareas and is designed to capture the highly contaminated groundwater prior toexiting the landfill property. A second, downgradient facility would belocated offsite to capture residual contamination present within the aquifer.The recommended system would extract groundwater at a relatively low flow rate(609 gpm total for the source area system and 330 gpm total for thedowngradienf system) and is not expected to cause a significant change in the

4-24 ^303727

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areas. Thus, this groundwater extraction and treatment facility does notimpact the need for dewatering the saturated overburden to treat thecontaminated soils.

|

The potential use of the source area groundwater treatment facility for

i treating groundwater from the overburden dewatering operations was evaluated.The extremely low flow rate of the dewatering wells (2.6 gallons/day/well) and

I the contaminant loadings are estimated to be less than one percent of the

treatment facility's design parameters. Therefore, it was concluded that theI NUS treatment facility would be able to accommodate the treatment of theI groundwater from the dewatering operations without significant problems

(Appendix C).

iBecause the groundwater treatment facility may not be built in time to treat

1 the groundwater for dewatering, treatment with activated carbon beforedischarging to surface water was evaluated. The estimated cost for this is inAppendix B.


' This alternative does not pose substantial risks to the surrounding communityor the environment during implementation. Dust and vapor may be generatedduring excavation, grading, drilling, and installation of wells. Dust control

and proper protective respiratory equipment during these activities would berequired. Air monitoring of the work area breathing zone could be performed.Perimeter air monitoring may be needed to determine whether steps are neededto protect the community from adverse air emissions during construction.

The time estimated for the cap construction is approximately three months, andfor the vacuum extraction/dewatering up to two years including pilot-scaletesting of the dewatering system.

III

4-27 BR30373Q


The reliability of a soil dewatering system for the saturated soil zone cannotbe predicted with available information. A more detailed subsurface investi-gation and pilot-scale testing of the dewatering system are required toevaluate the effectiveness of this option. This information could be gatheredduring the remedial design or the first phase of a remedial action.

With the remediation of hot spots and extension of the existing cap over thecontaminated area, the contamination of groundwater from the contaminatedsoils would be reduced. This alternative would be effective in achieving theremedial action objective in the long term.


Capping would significantly reduce the migration of contaminants from the soilto the groundwater. The remediation of hot spots through vacuum extractionand soil dewatering would reduce the soil contaminants to levels that are nolonger of concern for migration to the groundwater once a synthetic membranecap is in place. Approximately 4,900 cubic yards of contaminated soil wouldbe treated to below 58,600 ug/kg of TCE, with approximately 900 pounds of VOCsremoved.

Residuals remaining after implementing the alternative include the lesscontaminated soils that are not remediated at the site, the contaminated waterfrom soil dewatering and vacuum extraction, the spent activated carbon, andthe fluid for equipment decontamination. The contaminated water would becollected and treated by either activated carbon or the onsite groundwaterextraction treatment facility designed by NUS.

Implementability

A phased approach is recommended for implementing a combination vacuumextraction and dewatering system. During the initial phase, the shallowvacuum extraction system and several dewatering wells would be installed. In

a latter phase, the remainder of the dewatering wells, the deep vacuum

4-28

extraction system, and the cap extension would be installed. The reasons fora phased approach are several. First, the installation and operation of theshallow system would allow for identification of the more highly contaminated

areas and for debugging of the full-scale system operating parameters.

Second, the shallow soils are projected to achieve the cleanup criteria withinone year, hence the overall project may be extended by only one year whilevaluable operating knowledge is gained. Third, the operating equipment used

for both the shallow and the deep systems are similar and savings in capitalcosts could be achieved by utilizing the same equipment for the shallow andthe deep systems. Fourth, the dewatering system would require a more detailedsubsurface investigation and pilot-scale testing before the full-scale designis performed. Once the dewatering system is functioning properly, vacuumextraction of the saturated soil zone can be initiated.

An onsite staging area would be required for storing clean and used carboncanisters. A RCRA-permitted hazardous waste disposal facility may be required

to receive the spent activated carbon if it is not regenerated.

Cost

The estimated capital cost of Alternative 4a is $1,360,000. This costI includes the removal of the underground storage tank near the abandoned

building ($10,000). The estimated O&M costs for the first year are $243,000

I which includes O&M costs for the cap, vacuum extraction, and soil dewatering,and $23,000 per year for 30 years afterwards for cap inspection andmaintenance. The total present worth is estimated to be $2,010,000. Thedetailed cost estimate is provided in Appendix B.


This alternative would use a combination of treatment and containment to meetthe contaminant-specific ARARs. Once the contaminated area has been capped,it is predicted that TCE concentrations below 58,600 ug/kg in the soil wouldnot cause drinking water and health-based standards to be exceeded in thegroundwater.

4-29 flR303732


Action-specific ARARs would need to be addressed for air emissions (NESHAPs),offsite transport of spent activated carbon (DOT rules for Hazardous MaterialsTransport and Pennsylvania Hazardous Substance Transportation Regulations),disposal (RCRA and the Pennsylvania Solid Waste Management Act), and workersafety (OSHA, TLVs). It is expected that all of the action-specific ARARscould be met under this alternative.


This alternative is expected to reduce the contaminant migration from the soilto the groundwater and treat the highly contaminated soils to meet the soilcleanup goals. Although it still leaves the less contaminated soils in place,this alternative would reduce the contaminant migration by extending the capand treating the hot spots, and therefore, is expected to meet the remedialaction objective of protecting the groundwater.

4.2.4.2 Alternative 4b: In-situ Steam Stripping and Extension of ExistingCap

This alternative includes using the in-situ steam stripping process, described

under Alternative 3b, to remediate the contaminated soil hot spots, andplacing a cap over the less contaminated soils. Soils would be treated fromthe surface to the bedrock, including the saturated soils. Unlike vacuumextraction, in-situ stream stripping does not require dewatering to beeffective in the saturated soil zone. The approximate locations of thein-situ steam stripping treatment blocks are shown in Figure 4-6. A crosssection of the remediation area is shown in Figure 4-7.


Remediation of the hot spots would be performed in treatment blocks ofapproximately 30 square feet to depths of approximately 70 feet (approximatedepth to the top of bedrock). Assuming a treatment rate of 10 cubic yards per

4-30 3R303733

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4-32

hour, the time to remediate the area with TCE-contaminated soils greater than58,600 ug/kg is approximately one year. Because of the developmental status

of this technology, onsite pilot-scale testing may be warranted and may addanother year to the overall remediation time. Placement of the cap extension

! is estimated to take three months.I

Sections of the existing cap over the hot spots would need to be removed toremediate the soil and be replaced afterwards. Approximately 1,600 square

l feet of cap would be affected.

During the remediation process, the risks to site workers and the community

I are expected to be minimal since the in-situ steam stripping operates as aclosed-loop system. Appropriate respiratory protection would need to be

1 adhered to during construction of the cap extension and any other time a

worker may be in contact with contaminated soils or vapors. No adverseenvironmental impacts are anticipated.ILong-Term Effectiveness

The residual risk of leaving contaminated soils onsite is expected to be small

since the rate of contaminant migration to the groundwater would be low if theintegrity of the cap is maintained. The reliability of the cap system isexpected to be good.


This alternative would treat the contaminated soil hot spots, remediatingapproximately 18,700 cubic yards of soil to below the 58,600 ugAg TCE leveland removing approximately 1,100 pounds of VOCs. The remaining contaminated

soil would be capped to minimize the mobility of VOCs into the groundwater.The treated soils may become recontaminated by diffusion of VOCs from thesurrounding untreated soils; however, contamination levels should remain belowthe 58,600 ug/kg TCE action level.

4-33 &R303736

Implementabilitv

To implement this alternative, a steam stripping system capable of reaching tothe top of the bedrock (approximately 70 feet) would be needed. Portions ofthe existing landfill cap would need to be removed prior to the soil

remediation and replaced afterwards. The cap extension would be constructedafter remediation of the soil outside of the existing cap is completed.Other aspects of implementability are discussed under Alternatives 2 and 3b.

Capital cost for this alternative is based on a $100/cubic yard treatmentcost, installation of a cap extension ($540,000), and removal of theunderground storage tank located near the abandoned building ($10,000). The

present worth value of this alternative is approximately $2,850,000. Adetailed cost estimate is presented in Appendix B.


This alternative is expected to meet contaminant-specific ARARs by attainingthe soil cleanup goals with a synthetic membrane cap in place. Location-specific ARARs are not applicable or relevant and appropriate to thisalternative.

Action-specific ARARs would need to be addressed for potential air emissions(NESHAPs), treated discharges (CWA), offsite transport and disposal of anyresiduals (RCRA, DOT Rules for Hazardous Materials Transport, PennsylvaniaHazardous Substance Transportation Regulations,, and the Pennsylvania SolidWaste Management Act), cap construction (RCRA, Pennsylvania Storm WaterManagement Act), and worker safety (OSHA, TLVs). It is anticipated that allaction-specific ARARs could be met under this alternative.


This alternative is expected to meet the remedial action objective and,therefore, reduce the contaminant loading of the groundwater to acceptable

4-34 ^303737

4.2.5 Alternative 5: Limited Treatment of All Soils--34 ug/kg TCE ActionLevel Outside the Existing Cap and 58.600 ug/kg TCE Action LevelInside the Existing Cap

4.2.5.1 Alternative 5a: Vacuum Extraction and Soil Dewatering

As discussed under Alternative 3a, vacuum extraction alone is not effectivefor contaminant removal in saturated soil. Remediation of the saturated soilrequires simultaneous water extraction along with vacuum extraction.

Overburden soil dewatering is identified in Section 2.3 as the technology bestsuited for this application.

A conceptual design of this alternative would be similar to that ofAlternative 3a (Figure 4-2), except that vacuum extraction and dewateringwells would be placed in the overburden soil below the groundwater table. The

average depth of these wells is estimated to be 70 feet. Operating vacuum ofu.

approximately 15 inches of mercury with an air flow rate of approximately7 cfm per well would be required. Air injection wells would increase theradius of influence of the deep vacuum extraction wells in the lowerpermeability soils. An air injection rate of approximately 70 cfm at anoperating pressure of 50 psi would be required at each designated airinjection wellpoint. Dewatering wells would be equipped with submersiblepumps and are predicted to yield an average flow rate of approximately2.6 gallons per day at each wellpoint. It is anticipated that the bestdewatering results can be achieved when vacuum extraction and dewatering areperformed in the same well or in a pair of nested wells.


The short-term effectiveness of this alternative would be very similar to thatof Alternative 3a. Dermal and respiratory protection would be required toprevent exposure of workers to contaminated water or spent activated carbon.Proper respiratory protection would minimize worker exposure during drillingand sampling operations. During operation of the vacuum extraction system,contaminated soil gas would be treated to safe levels. The time estimated forremediating the soils with Alternative 5a is five years.

4_35 HR303738


Because this alternative would remediate soils to the soil cleanup goals bothinside and outside of the existing cap, remedial objectives would be achieved.


This alternative would remove approximately 7,000 pounds of VOCs from237,000 cubic yards of soil, mostly from the portion of the source areasoutside of the existing cap. This represents approximately 54 percent of thetotal contaminants in the soil. Potential toxicity of the contamination isreduced because of the reduction in the volume of contamination. Residuals

remaining after implementation include the remaining contaminants in the soil(approximately 5,900 pounds of VOCs, mostly under the existing cap), the spent

activated carbon, and the extracted or pumped groundwater. The contaminatedwater would be treated onsite either by the groundwater extraction treatmentfacility designed by NUS or by an activated carbon treatment system. Thespent activated carbon would either be regenerated or disposed offsite.

Implementabilltv

Vacuum extraction is demonstrated and commercially available. Thisalternative would require approximately eight shallow soil vacuum extractionwells, 160 deep soil vacuum extraction wells, and 320 dewatering/vacuumextraction wells for saturated soils to remediate soils outside of theexisting landfill cap. A total of four dewatering/vacuum extraction wellswould have to be installed inside the existing cap boundary to treat thecontaminated soil to the cleanup action level represented by 58,600 ug/kg of

TCE.

Overburden soil dewatering in the tight clayey soil at the Heleva Landfill

Site would be very slow (estimated flow rate at 2.6 gallons per day perwell--see Appendix C for backup calculations), yet adequate enough tofacilitate the vacuum extraction of VOCs in the same or nested wells.

4-36 1R303739

III

An onsite staging area would be required for storing clean and used carboncanisters, if needed. A RCRA-permitted hazardous waste disposal facility must

be able to receive the used carbon canisters if the carbon is disposed

offsite.

Cost

The estimated capital cost for Alternative 5a is $15,200,000, including$10,000 to remove the underground storage tank and $2,240,000 for theactivated carbon treatment for the dewatering pumpage. The estimated annualO&M cost is $1,670,000. The present worth of Alternative 5a is estimated to

be $22,600,000. The detailed cost estimate calculation is presented in

Appendix B.


This alternative would meet contaminant-specific ARARs by achieving the soilcleanup goals.



Action-specific ARARs would need to be addressed for air emissions (NESHAPs),offsite transport of spent activated carbon (DOT rules for Hazardous Materials

Transport and Pennsylvania Hazardous Substance Transportation Regulations),disposal (RCRA and the Pennsylvania Solid Waste Management Act), surface waterdischarges (CWA), and worker safety (OSHA, TLVs). It is expected that all ofthe action-specific ARARs could be met under this alternative.


This alternative is expected to achieve the soil cleanup goals and thereforemeet the remedial action objective.

4-37


Alternative 5b is similar to Alternative 3b with the exception that thesaturated soils will also be remediated under this alternative. All the otherfeatures of this alternative are the same as Alternative 3b (Figure 4-3).


The process is essentially a closed-loop system, so respiratory protection forthe workers would not generally be required. Respiratory protection may benecessary during sampling activities, maintenance, or any other time a workermay be directly exposed to the site contaminants. Exposure risks to thecommunity or adverse environmental impact during the remediation are notanticipated.


Because this alternative is designed to remediate soils within the sourceareas to acceptable cleanup levels both inside and outside of the existingcap, it is expected that the remedial action objective would be achieved.


This alternative would remove approximately 7,200 pounds of VOCs from thesoil, mostly from the portion of the source areas outside of the existing cap.The total soil volume remediated would be 237,000 cubic yards. Thisrepresents approximately 55 percent of the total contaminants in the soil.Residuals remaining after implementation include the remaining contaminants inthe soil (approximately 5,800 pounds of VOCs, mostly under the existing cap),

and condensed VOCs from the treatment system (which would be incineratedoffsite). The soil treatment is irreversible in that the remediated soilswould not cause further contamination.

Implementability

At present, only one unit has been constructed. Other units capable ofoperating at greater depths than the demonstration unit are under construction

4-38 AR3037M

IIl' and could be ready with six months' notice, according to the developer. It

was assumed that two more units would be available to operate at the HelevaLandfill Site.

Two areas outside the existing landfill cap, shown in Figure 4-3, would needto be remediated to the action level of 34 ug/kg TCE. The in-situ steamstripping process, which treats approximately 30 square feet in a treatment

block, would require approximately 3,700 treatment blocks to remediate thespill areas outside of the cap. A small area under the cap containing soils

with TCE greater than 58,600 ug/kg could be remediated with approximately 54

treatment blocks. The actual number of treatment blocks would be determinedin the field by starting treatment in a known area of contamination and movingoutward until soils that meet the cleanup criteria were encountered. The timerequired to remediate these areas using three rigs is approximately fiveyears.

The reliability of the technology will be evaluated through the SITE programdemonstration project. The treatment train is complex and would require the

availability of specialized equipment and skilled workers to maintain.

Effectiveness of the treatment is continuously monitored by a flame ionizationdetector for total VOCs in the soil vapor. Contaminant concentrations in thesoil can also be measured in pre- and post-treatment soil samples to determinethe removal efficiency.

Cost

Unit costs for treated soil currently range from $125 to $150/cubic yard forthe SITE demonstration project. The developer anticipates that the unittreatment costs for a larger unit would range between $75 and $100/cubic yard.Assuming a $100/cubic yard treatment cost, the net present worth for thisalternative is $27,800,000. Costs for removing an underground storage tank($10,000) are included.

4-39


This alternative would meet contaminant-specific ARARs by achieving the soilcleanup goals.


Action-specific ARARs would include the CAA regulations for air emissions(NESHAPs), offsite transport of residuals from the treatment process (DOTrules for Hazardous Materials Transport and Pennsylvania Hazardous SubstanceTransportation Regulations), disposal (RCRA and the Pennsylvania Solid Waste

Management Act), and worker safety (OSHA, TLVs). There is expected to be no

difficulties in complying with the action-specific ARARs.


It is expected that this alternative would achieve the soil cleanup goals andtherefore would meet the remedial action objective.

4.2.6 Alternative 6: Full Treatment of All Soil--34 ug/kg TCE ActionLevel Both Inside and Outside Existing Cap

4.2.6.1 Alternative 6a: Vacuum Extraction and Soil Dewatering

In order to achieve full treatment of the overburden soils, it is proposedunder this subalternative that vacuum extraction be used in conjunction withsoil dewatering to remediate all of the soils within the source areas abovethe 34 ug/kg TCE action level. The soil dewatering process would lower thegroundwater table to the point where vacuum extraction becomes effective inthe saturated soils. This alternative is capable of achieving permanentreduction of the volume of contaminants in the soil which complies with one of

the goals of CERCLA.

4-40


Proper respiratory protection would be required for site workers duringdrilling and sampling activities. Contaminated groundwater generated during

the dewatering process would be treated by either an activated carbon systemor by the onsite groundwater extraction treatment facility. Spent activatedcarbon from the vacuum extraction process would be regenerated onsite ortransported offsite to a RCRA-approved facility for regeneration or disposal.To ensure safety to the surrounding community during dewatering operations andtransport of spent activated carbon, spill control equipment and procedures

would be used if a spill incident occurred.

The time required to complete remediation would be approximately five years.


This alternative is designed to use treatment as the only means of remediationto permanently remove contaminants from the soil. Assuming the vacuumextraction and soil dewatering processes achieve reduction below action

levels, there would be no long-term management, operation, or maintenancerequired.

Reduction of Mobility. Toxicity. or Volume

The combination of vacuum extraction and soil dewatering techniques is

designed to permanently reduce the levels of contaminants in the overburdensoils and groundwater. A total of 392,000 cubic yards of soil would betreated by this alternative. It is expected that no soil containingcontaminants above the cleanup goals would remain in the remediation areas.Approximately 12,600 pounds of VOCs would be removed, while about 330 poundsof VOCs would remain in soils containing less than 34 ug/kg of TCE.

Residuals remaining after treatment are groundwater from soil dewatering andcontaminated carbon from vacuum extraction. Groundwater would be treated tocomply with NPDES discharge regulations by either air stripping and activatedcarbon or the onsite groundwater extraction treatment facility designed by

4-41

NUS. Contaminated carbon would either be regenerated or transported offsiteto a RCRA-approved disposal facility.

Implementabilitv

Soil dewatering and vacuum extraction technologies are demonstrated andcommercially available. The phased approach discussed under Alternative 4awould be recommended during implementation of this alternative. Well spacingsmay have to be altered for dewatering to achieve effective pumping rates inthe tight silts and clays. This would be determined by well yield uponinstallation and monitoring the elevation of the top of the groundwater table.

As shown in Figure 4-8, it is estimated that 144 wells, including six shallowwells, would be installed through the existing landfill cap to treat thesubsurface soils. A synthetic membrane boot would be placed around each welland field seamed to the cap to maintain a hydraulic barrier. An additional165 wells, including eight shallow wells, would be necessary for the area

outside the landfill cap.

An onsite staging area would be required for the storage of materials andequipment for the construction of the dewatering and vacuum extractionsystems. This area could store the clean and contaminated carbon canistersused for the vacuum extraction process.

Cost

The estimated capital cost for Alternative 6a is $27,500,000, including$10,000 for removing an underground storage tank and $4,150,000 for theactivated carbon treatment of the dewatering pumpage. The estimated O&M costsare $2,630,000 per year. The estimated present worth of this alternative is$39,000,000. The cost breakdown and calculation are presented in Appendix B.


This alternative would use treatment to attain the soil cleanup goals and isexpected to meet the contaminant-specific ARARs.

4-42

I1I1

IIIII

4-43


Action-specific ARARs would need to be addressed for air emissions (NESHAPs),offsite transport of spent activated carbon (DOT rules for Hazardous MaterialsTransport and Pennsylvania Hazardous Substance Transportation Regulations),disposal (RCRA and the Pennsylvania Solid Waste Management Act), surface waterdischarges (CWA), and worker safety (OSHA, TLVs). It is expected that all ofthe action-specific ARARs could be met under this alternative.


It is expected that this alternative would achieve the remedial actionobjective by minimizing the migration of contaminants from the soil to thegroundwater. By permanently reducing the volume of contamination, thisalternative complies with one of the goals of CERCLA.


This alternative utilizes in-situ steam stripping to achieve full treatment ofthe contaminated overburden soils. The treatment area includes all

TCE-contaminated soils within the source areas greater than 34 ug/kg from thesurface to the top of bedrock, both outside and beneath the existing landfillcap.


Exposure of workers and the community to soil contaminants is not anticipatedduring the remedial action since the treatment process is essentially aclosed-loop operation. Site workers would need proper respiratory protectionif there is a potential for coming into contact with contaminated soil orvapor during sampling, maintenance, or other activities. No adverseenvironmental impacts are anticipated from this alternative.

The time required to remediate the area with this alternative is approximatelyfive years assuming five treatment units operating at the site.

4-44

I Long-Term Effectiveness

I At the completion of the remedial action, it is anticipated that the soilcontamination would be below the soil cleanup goals and would not be expectedto cause further groundwater contamination that would exceed drinking water or

health-based criteria. This alternative would provide treatment for the| contaminated area and would minimize long-term management and monitoring

requirements.


4 The alternative is expected to remove approximately 12,900 pounds of VOCs fromthe contaminated soil, causing a reduction in the volume of highly

I contaminated soils. The volume of soils treated to a depth of 70 feet would

be approximately 392,000 cubic yards. The treatment is irreversible in thatJ the treated soils would not cause further contamination to surrounding soils

or the groundwater. The residuals remaining after treatment are condensed

VOCs from the treatment train and spent activated carbon that would bedisposed offsite.

Implementability

Remediation of soils beneath the existing landfill cap with a batch in-situsteam stripping process would require that portion of the cap to be removedprior to treatment. Alternatively, the continuous mode steam stripping

process which utilizes steam injection and vacuum extraction wells could beinstalled without removing the cap over the remediation area. Theimplementability of each technique in a landfill environment has not yet been

_ well demonstrated since these are emerging technologies. Further evaluation| through onsite pilot-scale testing or other field demonstration programs would

be required to determine implementation requirements.

A batch unit capable of treating the depth of soil required under thisI alternative would need to be constructed. According to the developer, a

six-month lead time would be required for mobilization. As shown inFigure 4-9, approximately 3,650 treatment blocks would be required outside the

4.45 flR3037ls8

i

4-46

I

II

existing landfill cap and approximately 2,990 treatment blocks would berequired for soils under the cap. Using the batch in-situ steam stripping

process, approximately 89,600 square feet of cap would need to be removedprior to treatment.

Effectiveness of the treatment is continuously monitored by a flame ionizationdetector for total VOCs in the soil vapor. Contaminant concentrations in thesoil can also be measured in pre- and post-treatment soil samples to determine

the removal efficiency.

Cost

For the batch process, unit costs for treated soil currently range from $125to $150/cubic yard for the SITE demonstration project. The developer

anticipates that the unit treatment costs for a larger unit would rangebetween $75 and $100/cubic yard. Assuming a $100/cubic yard treatment cost,the net present work for this alternative is $47,700,000. The cost for

removing an underground storage tank ($10,000) has been included. Cost dataare not yet available for the continuous mode steam stripping process.


This alternative is expected to meet contaminant-specific ARARs by attainingthe soil cleanup goals. Location-specific ARARs are not applicable orrelevant and appropriate to this alternative.

Action-specific ARARs would need to be addressed for potential air emissions(NESHAPs), offsite transport of residuals (DOT Rules for Hazardous MaterialsTransport, Pennsylvania Hazardous Substance Transportation Regulations),disposal (RCRA and the Pennsylvania Solid Waste Management Act), and workersafety (OSHA, TLVs). It is anticipated that all action-specific ARARs couldbe met.

4-47 flR303750

Overall Protection of H"mar> Health and the Environment

This alternative is expected to meet the remedial action objective and,therefore, minimize the loading of contaminants from the soil into thegroundwater.

4.3 COMPARISON OF ALTERNATIVES

In this section, the alternatives and technologies are compared according tothe seven evaluation criteria used in Section 4.2. To simplify comparison ofthe various alternatives and subalternatives, two separate comparisons will bepresented: a technology comparison and an alternative comparison. Thetechnology comparison section provides evaluations of the subalternatives(vacuum extraction and in-situ steam stripping) which apply to each of thefour treatment alternatives.

4.3.1 Technology Comparison

A summary matrix of the technology comparison is given in Table 4-2. Threesubalternatives are compared: vacuum extraction, vacuum extraction withdewatering, and in-situ steam stripping.

As shown in Table 4-2, the comparisons of the three technology groups aresimilar for their short-term effectiveness and compliance with ARARs. Thecombined vacuum extraction/soil dewatering and in-situ steam stripping arebetter than vacuum extraction alone in their long-term effectiveness,reduction of toxicity, mobility, or volume, and overall protection of humanhealth and environment. Vacuum extraction and soil dewatering technology iscurrently more implementable than in-situ steam stripping. Cost can becompared only when the target soil volume to be remediated is the same.

4.3.2 Alternative Comparison

A summary matrix of the alternative comparison is given in Table 4-3. Thealternatives are compared according to the seven criteria listed in Table 4-1

of Section 4.2.

4-48 1R30375I

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Short-term Effectiveness

With respect to the time required to complete remediation, the10 subalternatives are ranked as follows:

i1. Alternative 1 (0 months)2. Alternative 2 (three months)

3. Alternatives 4a and 4b (approximately two years)j 4. Alternatives 3a, 3b, 5a, 5b, 6a, and 6b (approximately five years)

. Alternatives 1 and 2 are the only alternatives that do not include treatment| of the subsurface soils. Alternatives 3, 4 and 5 include some type of

treatment and, therefore, present potential exposure to workers, the

1 community, and the environment due to uncontrolled discharges of gases andaqueous effluents from system failures. In general, the degree of risk due to

1 construction activities increases with the amount of time needed to implementthe remedial action. With proper safeguards, the degree of risk to onsiteworkers is expected to be minimal and controllable. Perimeter and work areaair monitoring, personal protective equipment, spill control procedures,process equipment checks, and other health and safety procedures would allhelp to minimize risks associated with onsite activities.

Long-term Effectiveness

With respect to long-term effectiveness, the 10 subalternatives are ranked as

follows:

f

1. Alternatives 6a and 6b

2. Alternatives 4a, 4b, 5a, and 5b3. Alternatives 2, 3a, and 3b4. Alternative 1

Of all the alternatives, only Alternatives 4a, 4b, 5a, 5b, 6a and 6b wouldachieve the soil cleanup goals. Within this group, Alternatives 6a and 6bwould provide the greatest degree of long-term effectiveness, because all ofthe soil which is contaminated above the lower soil cleanup levels

4-65 RR303768

(represented by a soil TCE concentration of 34 ug/kg) would be remediated.Furthermore, Alternatives 6a and 6b would clean up the soil permanently, whichwould minimize long-term management and monitoring requirements for the site.

Alternatives 4a, 4b, 5a, and 5b would provide an adequate degree of long-termeffectiveness. These alternatives would need long-term management andmonitoring to ensure that the cap provides the proper containment.

The other alternatives would not achieve the soil cleanup goals. Alternatives3a and 3b would remove contaminants from only the unsaturated soils, and

Alternative 2 would only minimize the contaminant migration. UnderAlternative 1, the current site conditions would prevail.


With respect to the reduction of toxicity, mobility, or volume, the 10subalternatives are ranked as in Table 4-4. The reduction of toxicity is acomposite result from the reduction of contaminants and their mobility.

As shown in Table 4-3 and backup calculations in Appendix C, Alternatives 6aand 6b would be able to remove approximately 12,600 and 12,900 pounds,respectively, of the estimated total of 12,970 pounds of VOCs in the soils atthe Heleva Landfill Site, resulting in a 97 to 99.7 percent reduction.Alternatives 5a and 5b would be able to treat approximately 7,000 and7,200 pounds, respectively, of VOCs for a 54 to 55 percent reduction.Alternatives 3a and 3b would be able to treat a total of approximately3,100 and 3,200 pounds of VOCs, respectively, for a 24 percent reduction.Alternatives 4a and 4b would be able to treat 900 and 1,100 pounds of VOCs for

a 6 percent and 8 percent reduction, respectively. Alternatives 1 and 2, withno soil treatment, would have no net source reduction.

Capping, however, would be efficient in reducing the infiltration of rainwaterthrough the soil and would result in the reduction of contaminant mobility.The three alternatives that include extending the existing landfill cap (2,4a, and 4b) provide a high degree of contaminant mobility reduction. Asynthetic membrane cap would reduce rainwater infiltration from approximately

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TABLE 4-4

COMPARISON OF ALTERNATIVES BY REDUCTION OF TOXICITY, MOBILITY, OR VOLUME


Rank

1

2

3

4

5

Reduction ofToxicity

Alternatives 4a, 4b,5a, Sb, 6a, and 6b

Alternatives 3a and3b

Alternative 2

Alternative 1

——

Reduction ofMobility

Alternatives 2, 4a,and 4b

Alternatives 5a, Sb,6a, and 6b


Alternative 1

——

Reduction ofVolume





Alternatives 1 and 2

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2 inches annually to 0.0011 inches annually (as shown in Appendix A). Theother alternatives would not achieve contaminant mobility reduction except asa function of reducing contaminant concentrations.

By combining the reduction of contaminant source (volume) and the reduction ofmobility, a qualitative ranking of the reduction of toxicity is estimated andpresented in Table 4-4. Alternatives 4a, 4b, 5a, 5b, 6a, and 6b are rankedhighest with respect to this criterion.

Implementability

With respect to implementability, the 10 subalternatives are ranked asfollows:

1. Alternative 12. Alternative 2

3. Alternative 3a4. Alternative 4a5. Alternative 5a6. Alternative 6a7. Alternative 3b8. Alternative 4b

9. Alternative 5b10. Alternative 6b

Alternatives 1 and 2 are the only alternatives that would not includetreatment of the soils, and would therefore be the most easily implemented.Of the other alternatives, the ones that use vacuum extraction and soildewatering would be more implementable than the ones that use in-situ steamstripping because in-situ steam stripping is currently an emerging technology

with only a few dedicated vendors. Within the groups of alternatives that usethe same technology, the limited treatment alternatives (e.g., Alternatives 3,4, and 5) would be more implementable than the full treatment alternative(Alternative 6).

A comparison in implementability of the different technologies is presented in

Table 4-2.

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Cost

With respect to cost, the 10 subalternatives are ranked by comparing their

present worth in Table 4-5. The breakdown in capital costs, 06cM costs, andpresent worth costs for the 10 alternatives is presented in Table 4-3. Thebackup calculations of these estimates are provided in Appendix B.


Alternatives 4a, 4b, 5a, 5b, 6a, and 6b, by being able to achieve soil cleanupgoals, would meet the contaminant-specific ARARs. The other alternativeswould not meet the contaminant-specific ARARs. There are no location-specific

ARARs to be considered. Several action-specific ARARs concerning the remedialactions for each alternative are listed in Table 4-3.


With respect to remediation of contaminated soils to prevent additionalcontamination of the groundwater, the 10 subalternatives are ranked asfollows:

1. Alternatives 4a, 4b, 5a, 5b, 6a, and 6b2. Alternative 23. Alternatives 3a and 3b4. Alternative 1

Alternatives 4a, 4b, 5a, 5b, 6a, and 6b would achieve the soil cleanup goalsand thus would adequately protect the groundwater beneath the site.Alternatives 2, 3a, and 3b would not be able to achieve the remedial actionobjective; however, some reduction of mobility or volume would occur.Alternative 1 does not achieve the remedial action objective.

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TABLE 4-5

PRESENT WORTH COMPARISON OF ALTERNATIVES


Rank

1

2

3

4

5

6

7

8

9

10

Alternative

1

2

4a

4b

3a

3b

5a

5b

6a

6b

Present Worth

$ o$ 904,000

$ 2,010,000

$ 2,850,000

$ 6,800,000

$ 19,100,000

$ 22,600,000

$ 27,800,000

$ 39,000,000

$ 47,700,000

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REFERENCES

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Brubaker, G.R., 1989. "Screening Criteria for In-Situ Biorecl«amation ofContaminated Aquifers." The Sixth National Conference on Hazardous Wastes andHazardous Materials, April 12-14, New Orleans, Louisiana.

Dev, H., et al., 1988. "Field Test of the Radio Frequency In-Situ SoilDecontamination Process." In Superfund '88: HMCRI's Ninth NationalConference and Exhibition, November 28-30, Washington, D.C.

Frost, P., 1989. MTA Remedial Resources, Inc. Personal conununication,August.

Gannett Fleming, Inc., 1989a. Final Work Plan. Heleva Landfill Site. LehighCounty. Pennsylvania. EPA Work Assignment Number 37-05-3L59.0.

Gannett Fleming, Inc., 1989b. Final Prelect Operations Plan. Heleva LandfillSite. Lehi2h County. Pennsylvania. EPA Work Assignment Number 37-05-3L59.0.

Gannett Fleming, Inc., 1989c. Evaluation of Source Control Technologies;Heleva Landfill Site. Lehigh County. Pennsylvania. EPA Work AssignmentNumber 57-05-3L59.0.~

Gannett Fleming, Inc., 1990. Final Focused Remedial Investigation. HelevaLandfill Site. Lehigh County. Pennsylvania. EPA Work Assignment Number57-05-3L59.0.

Gannett Fleming, Inc., 1991. Final Amendment Focused Remedial Investigation.Heleva Landfill Site. Lehigh County. Pennsylvania. EPA Work AssignmentNumber 57-05-3L59.0

The Hazardous Waste Consultant. 1988. May/June issue.

Hutzler, N.J., B.E. Murphy, and J.S. Gierke. State of Technology Review:Soil Vapor Extraction Systems. Hazardous Waste Engineering ResearchLaboratory, Cincinnati, Ohio.

Loehr, R.C. and R.M. Kabrick, 1989. "Bioremediation of Contaminated Soil."The Sixth National Conference of Hazardous Wastes and Hazardous Materials,April 12-14, New Orleans, Louisiana.

Malmanis, E., D.W. Fuerst, and R.J. Piniewski, 1989. "Superfund Site SoilRemediation Using Large-Scale Vacuum Extraction." Presented at the SixthNational Conference of Hazardous Wastes and Hazardous Materials, April 12-14,New Orleans, Louisiana.

NUS Corporation, 1985. Remedial Investigation Report and Feasibility Study ofAlternatives. Heleva Landfill Site. Lehigh County. Pennsylvania. EPA WorkAssignment Number 48-3L59.

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Summers, K.S., Gherini and C. Chen, Tetra Tech Inc., 1980. Methodology toEvaluate the Potential for Groundwater Contamination from Geothermal FluidRelease. EPA-600/7-80-117.

U.S. Environmental Protection Agency, 1984. The Hvdrologic Evaluation ofLandfill Performance (HELP) Model. Volume I. User's Guide for Version I.Office of Solid Waste and Emergency Response. EPA/530-SW-84-009.

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U.S. Environmental Protection Agency, 1988a. Superfund Exposure Assessment_(_._,,-1 (\fGS~* ~f D-,™^-J4-l O _______ T7T>« /CY O /I OO /nnin TlU . » w&*>_,*«'C •a'A. •.v MiaS u.d.ca A. **Z «r y vri£ta< t. , JUA f*f «f^ \f f 4, " WW^ W A. a

U.S. Environmental Protection Agency, 1988b. Guidance for Conducting RemedialInvestigations and Feasibility Studies Under CERCLA. Interim Final. Office ofEmergency and Remedial Response. EPA/540/G-89/004.

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U.S. Environmental Protection Agency, 1989c. CERCLA Compliance With OtherLaws Manual: Part II. Clean Air Act and Other Environmental Statutes andState Requirements. Office of Solid Waste and Emergency Response.EPA/540/G-89/009.

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Documents

REVISED FINAL · 2020. 12. 27. · REVISED FINAL FOCUSED FEASIBILITY STUDY HELEVA LANDFILL SITE LEHIGH COUNTY. PENNSYLVANIA I I EPA WORK ASSIGNMENT NUMBER 37-05-3L59.0 CONTRACT NUMBER