NCD980557656_19940601_NC State University (Lot 86 Farm Unit 1)_FRCBERCLA O_Technical Memorandum - Preliminary Identification and Screening of Technologies-OCR

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l!u. __ ~, ···"·· .. ._~.di r~:_:;,,:_·1<:;,j,,, .rr-.a -\
JUL 11994
:?~~~-'·: ::!T• •:; ::';'2~~ I
TECHNICAL MEMORANDUM
PRELIMINARY IDENTIFICATION AND
SCREENING OF TECHNOLOGIES
LOT 86 SITE
NORTH CAROLINA STATE UNIVERSITY
RALEIGH, NORTH CAROLINA
JUNE 1994
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TECHNICAL MEMORANDUM
PRELIMINARY IDENTIFICATION AND
SCREENING OF TECHNOLOGIES
NORTH CAROLINA STATE UNIVERSITY LOT 86 SITE
1.1 CONTENT
This document discusses the preliminary identification, development, and screening of
the technologies and process options that may be used to assemble the remedial alternatives for
the Lot 86 site. The steps involved in this process include:
•
•
•
Development of general remedial action objectives (RAOs) for study
media
Development of general response actions for study media
Identification and screening of remedial technologies and process options
within each general response action, based on implementability, likely
effectiveness and cost.
At this stage, it is believed that the Lot 86 site has two media of interest: groundwater
and the unsaturated subsurface soils (including the trenches). RAOs and general response
actions are considered for each medium. The following sections discuss the development of
the RAOs, general response actions, and the development and screening of technologies and
process options.
This document represents one step in an iterative process in the identification and
screening of remedial technologies. Generally, as new information is developed during the
course of future work, new options may be added for consideration, or those screened out
during earlier phases may be reconsidered. The information contained in this Technical
Memorandum is therefore considered to be preliminary, subject to update and improvement.
1.2 REMEDIAL ACTION OBJECTIVES
General project RAOs were developed during the scoping (work plan)
phase of the project and with the aid of applicable guidance. Figure 1-1
identifies the general RAOs for the site. RAOs are provided for protection of
human health and protection of the environment. Objectives specific to
protecting human health and the environment were considered for each
medium. The main goal of the objectives is to prevent exposure to contami-
nants in the subsurface soils and groundwater in excess of public health or environmental
standards. Specific RAOs for the protection of human health will be established later and will
BROWN AND CAWWEU I Technical Memorandum• }UM 1994
MEDIA
I. Groundwater
2. Subsurface soil
REMEDIAL ACTION OBJECTIVES
· 1-1 For human health:
Prevent exposure to contaminated water.
For environmental protection:
1-2 Prevent further groundwater quality degradation.
2-1 For human health:
Prevent exposure to contaminated soils.
For environmental protection:
2-2 Prevent further quality deterioration.
GENERAL RESPONSE ACTIONS
No action
Institutional actions
Containment
Containment/treatment
Removal/disposal
Removal/treatment/disposal
No action
Institutional actions
Containment
Containment/treatment
Removal/disposal
Removal/treatment/disposal
Figure 1-1 Remedial Action Objectives and Associated General Response Actions
i . • t t i
-tlaiFlG.-----------------
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specify the exposure medium, exposure route, and contaminant level because protection may
be achieved by reducing exposure or reducing contaminant levels. Protection of the environ-
ment includes the protection of future uses of natural resources.
Background
RA Os are chemical-specific, medium-specific, numerical concentration limits that should
address the contaminants and the pathways found to be of potential concern during the baseline
risk assessment process. Because a major objective of the goals is to protect human health to
a cancer risk range of I x 10·• to I x 10·• for carcinogens and to meet a threshold dose limit
for noncarcinogenic chemical toxicants, many of the issues and assumptions addressed in the
baseline risk assessment are used in the development of risk-based RAOs, such as exposure
pathway identification, land use assumptions, and institutional controls. As of this date, the
USEPA-sponsored baseline risk assessment is still in progress. Therefore, the guidance to be
obtained from this document is not yet available. RAOs will be refined after receipt and review
of the USEPA baseline risk assessment.
RAOs are also dependent on the identification of applicable, relevant, and appropriate
requirements (ARARs), as described below.
Types of Applicable or Relevant and Appropriate Requirements
USEPA divides ARARs into three categories: chemical-specific, location-specific, and
action-specific requirements. Chemical-specific requirements define acceptable exposure levels
to specific chemicals. Chemical-specific ARAR limits that must be met for specific contami-
nants within the groundwater and subsurface soils are also referred to as cleanup standards or
levels, discharge criteria, or action limits. All these terms are synonymous with the potential
ARAR limits. Location-specific requirements are restrictions placed on the concentration of
hazardous substances or on the conduct of activities because they occur in sensitive locations
such as wetlands. Action-specific requirements are controls or restrictions for particular
treatment, storage, and disposal activities related to the management of hazardous waste.
The final listing of ARARs will be presented in the Feasibility Study (FS) Report
(following receipt of the Risk Assessment) with the selection of ARARS being performed by
USEPA as part of the record of decision (ROD).
Chemical-Specific ARARs for Groundwater. Potential groundwater ARARs were
considered as directed in USEPA's national policy, as spelled out in the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). As stated in the preambles to these
regulations:
Groundwater that is not an actual or potential source of drinking
water may not require remediation to a 10-4 to 10·• level. (55 FR
46 8717, USEPA, 1990)
BROWN AND CAWWEU 3 Ter:ltllical Memorandum • Juu l!/94
The likelihood of exposure actually occurring should be consid-
ered when deciding the appropriate level of remediation. (55 FR
46 8710, USEPA, 1990)
The upper groundwater zone is not currently, nor is it ever likely to be a potential
drinking water source. Therefore, the groundwater ARARs should be risk-based. Groundwater
ARAR identification has been placed in abeyance pending receipt of risk assessment guidance.
Chemical-Specific ARARs for the Subsurface Soils. Human receptors may be exposed
to chemicals in soils as a result of incidental ingestion of soils, dermal contact, and inhalation.
However, exposure via inadvertent ingestion of soil would only result if chemicals of potential
concern were located within the surficial soils, which is not the case at the Lot 86 site (NCSU
Remedial Investigation (RI) Report, BC 1994). Chemical-specific ARARs will be developed
following receipt and review of the baseline risk assessment.
Location-Specific ARARs. Location-specific ARARs address site-specific aspects such
as a critical habitat upon which endangered or threatened species depend. Evaluation of
potential location-specific ARARs will include the site requirements, prerequisites, citation of
the actual regulation or law, and determination of whether it is actually an ARAR for the site
or not. The subject site is a university campus. No critical habitats or threatened or endangered
species have been identified on or near the site. At this time, it is believed that no location-
specific ARARs exist for the site.
Action-Specific ARARs. Action-specific ARARs address requirements for remediation-
specific activities such as capping, air stripping, and closure. Evaluation of potential action-
specific ARARs will include the site requirements, prerequisites, citation of the actual regulation
or law, and determination of whether it is actually an ARAR for the site or not. Action-specific
ARARs will be reviewed after the technologies development task is further refined.
1.3 GENERAL RESPONSE ACTIONS
General response actions describe actions that could satisfy the RAOs. General response
actions may include no action, institutional actions, containment, removal, disposal, treatment,
or a combination of these. The relationship of the general response actions to the RAOs is
shown on Figure 1-1.
No Action
The no action alternative is retained throughout the feasibility study process as required
by 40 CFR 300.430(e)(6). This provides a comparative baseline against which other alterna-
tives can be evaluated. In the no action alternative, the contaminated soil and groundwater
would be left "as is" and would be monitored on a continuing basis. The monitoring effort
would be utilized to guide future actions. For example, if monitoring data indicated that the
site's environmental conditions were deteriorating, other remedial options could be imple-
mented. On the other hand, continuously improving environmental quality data would be
utilized to demonstrate the contaminant plume's gradual dissipation.
BROWN A.ND CAWWEU 4 Technieal Memorandum -June 1994
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Institutional Action
Institutional action includes various access controls and deed restrictions. Although this
alternative provides no reduction of volume, mobility, or toxicity of the contaminants, it can
reduce or eliminate direct exposure pathways and the resultant potential risk to the public.
Containment
Another method of reducing the risk to the public is through containment, thus reducing
the mobility of the contaminants. To reduce mobility, the contaminated media must be isolated
from the primary transport mechanisms such as wind, surface water, groundwater, biological
means, and mechanical means. The isolation of the contaminated media may be accomplished
by the installation of surface and subsurface barriers to block or redirect any transport of media
away from the contaminants.
Removal/Disposal
The removal/disposal option consists of removing the contaminated medium by various
hydraulic, pneumatic, or mechanical means and directly disposing of this medium in an on-site
or off-site facility.
Containmentffreatment
The containment/treatment general response action would employ the same containment
technologies and related process options as the containment general response action and would
add a treatment action. The treatment would use one of several chemical and/or physical
treatment methods designed to reduce the toxicity, volume, or mobility of the contaminants
present.
Removal/freatment/Disposal
The last general response actions add a treatment technology to the removal/disposal
general response action combination previously cited such that the contaminated medium is
treated prior to disposal.
2.1 IDENTIFICATION AND INITIAL SCREENING OF TECHNOLOGY
TYPES AND PROCESS OPTIONS
The impacted media identified during the RI were the unsaturated subsurface soils and
groundwater. For each of these media, an initial list of remedial technologies and process
options are identified. These technologies are compiled from various USEPA documents as
well as other applicable references. Only technologies that are potentially applicable to the Lot
86 site are included. An initial screening for technical feasibility was performed on each of
these technologies and process options to eliminate those options not feasible based on site
conditions, and to reduce the original number of possible options to a smaller group of viable
options. Information regarding site characterization, contaminant types, and contaminant
BROWN AND CAWWELL 5 Tecl,,ricaJ Memorandum -Ju,-1994
concentrations was used to eliminate options that were either not applicable or could not be
implemented effectively at the site.
Screening Criteria
The screening process involved two steps. The initial screening was performed to
eliminate process options and possibly entire technology types based on technical implement-
ability. This required reviewing the process options relative to their applicability to the
identified site conditions. The second screening step was performed to evaluate the remaining
process options based on institutional implementability, probable effectiveness and cost. The
results of this two-step screening process are intended to provide a basis for selection, if
possible, of one representative process option for each technology, thus simplifying the next
stage, the detailed analysis of alternatives, a feasibility study task.
Technology Descriptions and Evaluations
A glossary of process options is· presented in Appendix A.
Initial Screening: Groundwater Medium. The general response
actions that are applicable for groundwater include no action, institutional
actions, containment, collection, treatment, and disposal and selected combina-
tions of these. These were described in Section 1.3. The technologies and
process options considered are summarized on Figure 2-1. Options screened
out in the first screening are indicated by shaded areas.
The technologies and process options considered for the groundwater medium are ·
summarized on Figure 2-1. Options screened out in the fust screening as not appropriate or
technically implementable are indicated by the shaded areas. A discussion of the rationale for
retaining or eliminating these options is furnished in the following paragraphs.
As required by USEPA guidance, the no action response action will be retained for
further consideration.
An alternate water supply is not required and was eliminated from consideration because
uncontaminated drinking water is currently available from the City water supply or is being
withdrawn from the lower regional aquifer, located at depths on the order of 300 feet below
ground surface.
Access restrictions, including deed restrictions, use restrictions, and use of fences or
signs, were retained.
Regarding containment via subsurface flow control, excavation to install subsurface flow
controls to the depth required at this site is not technically feasible. ·Consequently, the follow-
ing process options were eliminated as not technically feasible: slurry wall, grout curtain, and
sheet pilings. A cryogenic barrier was eliminated because it is a commercially unproven tech-
nology. Injection wells were eliminated as the site hydrogeology is not favorable for
implementing this type of flow control.
BROWN AND CAWWEU 6 T~clurical Mnnorrmdum • Ju.M 1994
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- - -- -- - - - -
General Response Action Technology Type - -- -
Process Option - --- -Assessment -
Technical Implementability
._ ____ _.N"'o'-A=ct"'io:..:n'---___ __.HL _____ ....:;N:..:i..::A;:_ _____ HL ______ :..:N.:..i.:..A=--------' Retain the option.
I
VA11eiiia1ewatersu
Institutional Action
· Access Restrictions
Containment tfSlibslirfa~e•·FIC)W···ContrC)i)!f••·· .·.
r-lL. ____ ..!E:!x~tr~a~ct!!lo~n~ ___ __J
H Subsurface Drains ._ __ .....;:;.===:....::..=~----'
Collection / Dlscharoe I
•··••ton:.s11eDisctiar
Off-Site Dlscharne
Deed Restrictions
Fences Si ns
Lower aquifer is uncontaminated;
alternate supply not required.
Retain the option.
Retain the option.
Not applicable at depths required.
Unproven technology.
Not applicable at depths required.
Nol applicable at depths required.
Site hydrogeology is unfavorable.
Not applicable and horizontal barrier
already exists.
Horizontal Extraction Wells I Retain the option.
._ __ V.:.;e,::rl.::l:Ca,::l..::E:::xl,.:;rc,a:.::c.:.:1I:on"--'-W:..:e:;;ll:.::s __ .... l Retain the option.
➔
i_ __ _:.:ln:..:le:::rc:c::::ec.pl:.:o;:.r..::T.:.;re::.:n:.:c::.:hc_ __ _,I Retain the option.
dl Site hydrogeology is unfavorable.
lrifiltriillori arid•Eva·iviratlont• !fl Site hydrogeology Is unfavorable and
large land area required not available.
I Not applicable.
._ ____ ..cC.:..ltv-'-'P-'O'-'TW _____ _,1 Retain the option.
•••• \SurfaceWater:Dlschar-A . ' Not applicable because of contaminants.
Figure 2-1 Initial Screening of Technologies and Process Options for Groundwater
General Response Action
Containment/ Treatment
Technology Type Process Option
· enlc Barrlerif
T<.rout•ln)ectlon\?
Bloreclamation
In Situ Treatment cliem1ca1••Reaci1onrn·•
Aeration
Assessment -
Technical Implementability
Not applicable at depths required.
Unproven technology.
Not applicable at depths required.
Not applicable at depths required.
Site hydrogeolagy Is unfavorable.
Not applicable and horizontal barrier
already exists.
Retain the option.
Unproven technology In In situ systems.
Retain the option.
r------,----,--------,_J .__.:;H:::o::..:ri:::.zo"'n"'t"'a'-'I E,.x:,:t,_,ra,.,c""ti:::o::..:n..:Wc:.;e::,l.:.,IS:...___,1 Retain the option.
Extraction n •r--------------, -----====------Ll Vertical Extraction Wells I Retain the option.
J Subsurface Drains Interceptor Trench I Retain the option. --------------
I Collection /Treatment/ Discharae J-rlr-----:-:--=:--:----:-------,1 EPA Best Demonstrated Available
-
Air Strlooln<1 Technology (BOAT).
Hc_ __ _;:Cc=a:.:rb:.:O:.:n:.:Ac:.d:::S:.:O:.:r,::Pt:.:lo:::n;;._ __ ....,1 EPA BDA T.
r-----=:---:----:-::--:-----:----, U{/ Phvsical Treatment •
(SolveiifEitraciloiii Vf\Vhfl Would add solvent constituents.
H? • i loif Eicliifri<ie{ >•• \\ I Not applicable to organic constituents. -~--~-~=-====-
H
'-'
•VRevirse•osm'oslsMY• t••>ti Not applicable to all contaminants
al concern.
Steam Strlnnfna I Retain the option.
Figure 2-1 (continued) Initial Screening of Technologies and Process Options for Groundwater
- - - -- - - -- -- - -- - - --
- -- - -- - - ----- -
General Response Action Technology Type Process Option
Chemical Treatment
Collection / Treatment I Dlschar e
Biolo ical Treatment Biotreatment
• ' >•••·•fnflltration.and.Eva oration) t•••·•
Cit POTW
Off-Site Dischar e
Potentially applicable technology.
- - --Assessment -
Technical Implementability
Not applicable to organic contaminants.
Not applicable to organic contaminants.
Retain the option.
Not applicable to organic contaminants.
Unproven technology.
Not applicable to organic contaminants.
Not effective treatment.
Not effective treatment.
Retain the option.
Site hydrogeoiogy is unfavorable.
Site hydrogeoiogy is unfavorable and
large land area required not available.
Not applicable.
Retain the option.
Not applicable because of
contaminants.
Figure 2-1 (continued) Initial Screening of Technologies and Process Options for Groundwater
-
Controls on vertical subsurface flow, such as grout injection, is not required at this site
because there is an existing confining layer between the shallow impacted groundwater and the
lower water-bearing units. As these artificial horizontal barriers cannot be adequately installed
at depths required, they would not provide any substantial benefits over the existing natural
barrier.
Horizontal and vertical extraction wells as well as an interceptor trench were retained as
groundwater collection methods.
Subsurface injection was eliminated from consideration as a discharge option because
the low permeability soils are unfavorable. Infiltration and evaporation were eliminated from
further consideration as discharge options because large areas of land are required, and this land
is not available on-site. Furthermore, the low permeability and cohesive soils comprising the
shallow water-bearing unit make this option technically infeasible.
Off-site discharge via a publicly owned treatment works (POTW), in conjunction with
both the removal/disposal and removal/treatment/disposal general response actions, was retained
because of the presence of the local POTW sewer system. Surface water discharge in conjunc-
tion with the collection/discharge general response action was eliminated because of the volatile
organic compounds (VOCs) present in the impacted groundwater.
In situ treatment process options for groundwater were considered. Bioreclamation may
possibly be implemented although the soil permeability in the shallow saturated zone may not
be adequate for nutrient and oxygen transport. Chemical reaction was eliminated because this
technology has only been demonstrated on water in aboveground treatment systems, not in situ
systems. Aeration or in situ stripping has been demonstrated to a limited extent, and may be
feasible for aquifers having low permeabilities; thus, this process option was retained.
Three of the physical treatment process options were removed from consideration during
the initial screening because of their limited applicability and implementability. Solvent extrac-
tion was eliminated from further consideration because it is not effective in treating low concen-
trations of organics in water, and it could introduce solvent constituents into the groundwater
during treatment. Ion exchange is not applicable for organics. Reverse osmosis is principally
used to remove dissolved salts and has not been adequately proven to effectively remove the
organics of concern. Air stripping, carbon adsorption, and steam stripping are physical treat-
ment processes which may be applicable to the subject site.
The chemical treatment processes of neutralization, prec1p1tation, reduction, and
hydrolysis were eliminated from further consideration because they do not effectively treat
water contaminated with the identified organic and volatile compounds. Photolysis is an
innovative technology that may be applicable to the contaminants, but it has not been
commercially proven and thus was eliminated. Photolysis may also partially degrade some
chemicals, producing potentially hazardous by-products. Oxidation was retained because it
could be applicable to most of the contaminants.
Both of the thermal treatment techniques (wet air oxidation and incineration) have also
been eliminated from consideration. Wet air oxidation and incineration are only practical for
BROWN A.ND CALDWEIL Tecl,IUCal Memorandum -Juna 1994
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relatively high concentrations of organic contaminants due to the energy required; these
processes would not be feasible for the low concentrations of contaminants present at the site.
Biological treatment of groundwater was retained as both an in situ or ex situ treatment
method.
Initial Screening: Unsaturated Subsurface Soil Medium. The general response
actions that are applicable for the unsaturated subsurface soil include no action, institutional
action, containment, removal, treatment, and disposal, and specified combinations of these.
These general response actions were described in Section 1.3.
The remedial technologies and process options considered for the
subsurface soil medium are summarized on Figure 2-2. Options not techni-
cally applicable or appropriate were eliminated, as indicated by the shaded
areas.
As required by USEPA guidances; the no action response action has been retained for
further consideration. Access restrictions, including deed restrictions, use restrictions, and use
of fences and/or signs, were also retained.
Capping was retained for further consideration. Capping may be especially effective
when used in a situation where the contamination is shown to be restricted in subsurface
mobility due to the nature of the soils. Capping is also a USEPA presumptive remedy for
municipal landfills, which have similarities to the Lot 86 site. Alternative materials for capping
include clay, asphalt, concrete, and synthetics.
Soil flushing was removed as an in situ treatment option because it would not be ef-
fective for clayey soils having low permeability, and because it is difficult to capture the
flushing agent. Soil vapor extraction was retained as it is a USEPA presumptive remedy for
the CERCLA sites with VOCs in unsaturated soils. In situ oxidation was eliminated because
it is a technology that has not been adequately demonstrated for soil with low permeability.
In situ vitrification was eliminated due to its innovative status and its intended application for
inorganic contaminants in soil. Inorganic stabilization similarly was eliminated as not
applicable to the organic contaminants at this site. Radio frequency heating was eliminated
because it is a commercially unproven technology. Steam/air stripping, in situ chemical
treatment, and bioremediation were also eliminated because they are best suited for highly
permeable soils and could be cost-prohibitive at the Lot 86 site.
Excavation was retained as the method of removal for soils. On-site disposal via a non-
RCRA landfill was eliminated because a facility for this purpose does not exist, and due to the
uncertainty of the site's future use, constructing such a facility is not a practical option. Off-site
disposal at a RCRA landfill was retained.
Ex situ physical treatment technologies to be used in conjunction with excavation,
including acid extraction, soil washing, and electrical separation, were eliminated because they
do not effectively treat organic compounds.
BROWN AND CAWWEU 11 Tecltlmal Memorandum -Ju,w 1994
General Response Action Technology Type
No Action H N/A H
Institutional Action Access Restrictions
Containment H Caeeing H
Capping
Containment/ Treatment
In Situ Treatment
Process Option
N/A
Deed Restrictions
Fencln SI ns
Concrete/Cla~/Synthetlc
Concrete/Clay/Synthetic
Soil Vapor Extraction
,w·chehiica1 Treatment?\
Assessment -
Technical Implementability
Retain the option.
Retain the option.
Retain the option.
Retain the option.
Retain the option.
Site hydrogeology not favorable and
flushing agent difficult to capture.
Retain the option.
Site hydrogeology not favorable.
Unproven technology in low permeability
soils.
Not applicable to organic contaminants.
Not applicable to organics.
Commercially unproven.
Site hydrogeology not favorable.
Site hydtrogeology not favorable.
Figure 2-2 Initial Screening of Technologies and Process Options for Soil
-------- - - - - - -- - - - -
- - - --General Response Action - - - - -
Technology Type - ---Process Option ----Assessment -
Technical Implementability
... Excavation Conventional Excavation I Retain the option . '---......:====:::....:==="'----'
•n;e: fllJoii'RCRAJ.!iiiiclflll'F/+• '/\I Not applicable.
L... __ _,R_,,e.,.m"'o:<;v:..,a:.:.I ,._/ ::D.:,IS="O:::S"'al'-__ ... 1 .... ._ __ ____:O:<,ff.,;·:,,S::,it,,e.,,Dc,;is,.,n,,,o,,,s,,,a.,_I ----'
'-------'-R:.::C:.:.R,::A,_F:.;ae,c::;il:,:it'-'--v ___ _,I Retain the option.
fNoii'RCRA Liinilfllf\i iii No such facility exists.
Excavation Conventional Excavation
, ••• chemIcaI Tieiititient:
Thermal Treatment Incineration
Off-Site Dis osal
RCRA Faclli
On-Site Dis osal
In-Place Re lacement
Potentially applicable technology.
Technology or process option that has been screened out.
Retain the option.
Not applicable.
Not applicable.
Not applicable.
Unproven technology.
Unproven technology.
Not applicable to organic contaminants.
Not applicable to organic contaminants.
Not effective treatment for voe
contaminants.
Retain the option.
Not effective treatment.
Not effective treatment.
Not applicable.
Retain the option.
Not applicable.
Retain the option.
Figure 2-2 (continued) Initial Screening of Technologies and Process Options for Soil
-
Chemical treatment, including oxidation and photolysis, was screened out due to the lack
of adequate demonstration of these technologies for large-scale remediation of soils contami-
nated with VOCs and other organics.
Thermal desorption, although effective on some chemicals, is not effective on all
contaminants and may not completely destroy some compounds, producing some potentially
hazardous by-products. Thus, this option was eliminated. Incineration was retained as the
method of thermal treatment for soils.
3.1 DEVELOPMENT AND SCREENING OF REMEDIAL ALTERNATIVES
The remedial alternative implemented at the site will likely be a combination of more
than one process option. To develop alternative remedial actions, the technologies and process
options which passed the initial screening (Section 2.1) are now subjected to a secondary
.. screening. The process options which pass the secondary screening will then be assembled into
various remedial alternatives. This section presents the secondary screening of the applicable
technologies and process options. It concludes with the summary of those alternatives selected
for detailed analysis in the FS Report.
Secondary Screening of Process Options
At the conclusion of Section 2.1, the technologies and process options
which passed the initial screening for the possible remedial alternatives were
summarized. The initial list of technologies and process options for the
groundwater and subsurface soil media was developed for this site to address
the remedial action objectives described in Section 1.2 of this report. The
applicable technologies and process options for the groundwater and unsatu-
rated subsurface soils which passed the initial screening are summarized on Figures 3-1 and 3-2,
respectively. These are now evaluated using the criteria of institutional implementability,
effectiveness and cost.
Where multiple process options for a given remedial technology remained after the
secondary screening, the best or most applicable ones were chosen to be used in developing
remedial technology alternatives in the feasibility study. The process options that were selected
to be carried forward are considered representative of the associated remedial technology and
were intended to preserve a wide range of options. Reasons for choosing or eliminating certain
process options are described in the following sections.
Groundwater Medium. The no action general response was retained for development
into an alternative as required by CERCLA. Deed restrictions were also retained because they
can be implemented to restrict groundwater use and the installation of wells until the
concentrations meet the ARARS established for the site.
The general response action of collection/discharge was eliminated because it could not
meet the preliminary RAOs, which require treatment of contaminated water.
BROWN A.ND CALDWEU 14 Tttltnkal Memorrutdum • Juu 1994
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-------------------General Response Action Technology Type Process Option
'-----""N""o""'A""c"'ti""o~n ____ _.1---i.r------;N:;-/~A•----, __ {-=.-=.-=.-=.-=.-=.-=.-=.-=.-=.-=.1N'L'l..!A1.-=--=--=--=--=--=--=--=--=-J
Deed Restrictions
Institutional Action Access Restrictions
Fences, Signs
Horizontal Extraction Wells
Extraction Vertical Extraction Wells
Collection / Dischar e Subsurface Drains Interceptor Trench
Off-Site Discharge City POTW
Bioreclamation
Containment I Treatment In Situ Treatment
Aeration
Figure 3-1 Applicable Technologies and Process Options for Groundwater
• ' i I 1 . ' ' ' •
General Response Action Technology Type Process Option
Horizontal Extraction Wells
Extraction
Vertical Extraction Wells
Subsurface Drains lnterce tor Trench
Air Strl In
Collection I Treatment/ Discher e Ph slcal Treatment
Chemical Treatment Oxidation
Biolo ical Treatment Blotreatment
Off-Site Discher e Cl POTW
Figure 3-1 (continued) Applicable Technologies and Process Options for Groundwater
I : '. "! I.' 1 ! . ' I'! I '~ •. t ' ! l I : : ~ ' . I'! ' . ' I j' l· \1 111 • ) f ! I . : , I l ' . t : • i ' \
-------------------
------------ - --- - --- - - -- -- - - --General Response Action Technology Type Process Option
No Action N/A N/A
Deed Restrictions
Institutional Action Access Restrictions
Fencin Si ns
Containment Capping Concrete/Clay/Synthetic
Ca in Concrete/Clay/Synthetic
Containment/ Treatment
In Situ Treatment Soil Vapor Extraction
Excavation Conventional Excavation
Removal / Disposal
Off-Site Dis osal RCRA Facilit
Excavation Conventional Excavation
Thermal Treatment Incineration
Removal /Treatment/ Dis osal
Off-Site Dis osal -J._ ___ ---'R..:;C,.,R"'A:..:...:.F.=aacc"'ili"'ty.._ ___ _,
On-Site Dis osal -l._ __ _.;.;ln.;..·.;..P;.;;la;.;;c.;;.e..;.R;.;;e.:;;p.;;;la;.;;c.;ce;.;.m;.;;e..;.n.;..t __ _,
Figure 3-2 Applicable Technologies and Process Options for Soil
The containment/treatment response action was retained. This alternative includes the
in situ treatment of groundwater through aeration and biotreatment.
Physical treatment using air or steam stripping are similar technologies. Steam stripping,
however, was eliminated because it does not provide any additional significant benefits over air
stripping for removal of the chemicals of potential concern and is typically more complex and
costly. Air stripping and chemical oxidation were then eliminated as process options for
groundwater, as they offer no advantage over carbon adsorption.
Biological treatment of the groundwater using a conventional aboveground activated
sludge reactor was eliminated due to its relative complexity in implementation, its moderate
effectiveness, and its moderately high costs. Chemical-specific ARARs also may not be
achieved using this option.
. Discharge of treated groundwater would be .to the local POTW, which was retained.
Subsurface Soil Medium. The· no· action general response action was retained for
development into an alternative as required by CERCLA. Deed restrictions on land use,
construction, and use of fences and signs were also retained.
For the containment/treatment general response action, capping utilizing concrete, along
with in situ soil vapor extraction, were retained for further consideration. Concrete is expected
to be more suitable for capping at the site than clay or synthetic materials.
For the general response action of removal/disposal, excavation followed by disposal in
an off-site RCRA landfill was considered. However, disposal without treatment cannot be
implemented because some of the soils are classified as RCRA-characteristic waste, which is
governed by the Land Ban Restrictions which require treatment prior to disposal. Therefore,
the removal/disposal action is not appropriate.
On-site incineration was chosen for consideration as the removal/treatment/disposal
process option for thermal treatment due to its relative availability in the commercial market
for treating large volumes of soil and its ability to remediate a wide variety of chemicals
including volatile organics and inorganics.
Development of Alternatives
Summaries of the retained process options for groundwater and soil are
presented on Figures 3-3 and 3-4, respectively. As shown on the figures,
these options have been assembled into remedial alternatives.
TM\7200TM1
BROWN AND CAWWEIL 18 Tecludeal Memorantbun • Ju• 199'
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- - -- -- - - - - --- -- -... -General Response
Action
Technology Type Process Option
._ ___ N_o_A_c_ll_on __ ~t---lL ___ ..:N/=A ___ _Jt---l1.. ___ ...cN/=A'------'
Institutional Action Access Restrictions Deed Restrictions
ContalnmenVTreatment H In Situ Treatment H Aeratlon/Blotreatment
Extraction ' Extraction System I ' ••
I Collection/Trtmnt/Discharge I--Combined
I,
H Physical Treatment , ' Carbon Adsorption I '
Combined
,I,
y Off-Site Discharge ' ' City POTW I ' '
Implementability
Easily Implementable
Easily Implementable
Implementable with
Difficulty
Implementable with
Difficulty
Easily Implementable
Easily Implementable
Effectiveness in
Meeting RAOs
Possibly Effective-
Long Term
Only Effective-
Long Term
Somewhat Effective-
Long Term
Somewhat Effective-
Long Term
Very Effective (BDAT)
Very Effective
Figure 3-3 Alternatives Retained Following the Secondary Screening
! r' j of Technologies and Process Options for Groundwater
Cost
Low
Low
High
High
High
Low
-
General Response
Action Technology Type Process Option Implementability
'---N_o_A_c_t_lo_n __ __.1----i._ ____ NI_A ___ __.H~----N/-A ___ __. Easily Implementable
Institutional Action
Containment/Treatment
RemovaVTrtmnt/Dlsposal
Deed Restrictions
Access Restrictions
Fencing, Signs
Capping Concrete
In Situ Treatment Soll Va or Extraction
Excavation Conventional Excavation
Thermal Treatment Incineration
On-Site Disposal In-Place Replacement
Easily Implementable
Easily Implementable
Easily Implementable
Implementable with
Difficulty
Implementable with
Difficulty
Implementable with
Difficulty
Implementable
Figure 3-4 Alternatives Retained Following the Secondary Screening
· ' of Technologies and Process Options for Soil '
- - -- --------- -
Effectiveness in
Meeting RAOs
Possibly Effective-
Long Term
Only Effective In the
Long_Term
Only Effective in the
Long Term
Effective -USEPA
rcresum~tive remedy or mun clpal landfills
Somewhat Effective
Somewhat Effective
Effective
Somewhat Effective
Combined with
Other Aternatlves
- - -
Cost
Low
Low
Low
Moderate
Moderate
High
High
Low
- -
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APPENDIX A
GLOSSARY OF PROCESS OPTIONS
Aeration is a technology by which air is introduced into a medium for the purposes of
removing volatile compounds. It can be accomplished through in situ injection of air into
groundwater or soil or ex situ treatment of groundwater or soil by a variety of methods.
Aerobic Biotreatment-see Bioremediation.
Air Stripping is a cost-effective and reliable method of removing volatile organics from
contaminated water. Air stripping is accomplished in a tower in which water cascades down
through a packing material while air is forced up through the packing by means of a blower.
Bioreclamation-see Bioremediation.
Bioremediation relies on microorganisms to transform hazardous compounds into innocuous
materials. Almost all organic compounds and some inorganic compounds can be degraded
biologically if given the proper physical and chemical conditions and sufficient time.
Block Displacement places an impermeable barrier around and beneath the contaminated zone.
The ground is physically displaced upward by pumping slurry, usually a soil bentonite and water
mixture, into a series of notched injection holes. A perimeter barrier is constructed in conjunction
with the bottom barrier.
Capping involves placing material such as clay, soil, concrete, asphalt, or synthetic material
over the top of the area of concern. This action often reduces the amount of leachate formed by
precipitation and helps prevent exposure through the surface.
Carbon Adsorption removes contaminants from aqueous wastes by contacting the stream with
a solid, activated carbon adsorbent in granular or powdered form. Organic compounds, and some
inorganic species, become bound to the surface of the carbon particles and are subsequently removed
along with the adsorbent. Carbon adsorption is primarily used to remove organic compounds with
low solubilities in water.
Chemical Reaction involves the addition of a chemical, such as hydrogen peroxide, that will
react with the constituents in the groundwater or soil such that the products of the reaction are
nonhazardous or more amenable to other forms of treatment (i.e., biological treatment).
Cryogenic Barrier is a technique that involves creating a frozen barrier using an underground
refrigeration system to control groundwater flow. The frozen zone acts as a barrier that prevents
the material from migrating into surrounding soils, groundwater, or nearby aquifers.
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Deed Restrictions are designed to prevent access/exposure to groundwater or soil by limiting
what can be done at the site. For example, deed restrictions may include limitations on the
installation of new wells.
Evaporation is used to allow water to evaporate into the atmosphere. It is accomplished
through ponds, or by spraying the water onto large areas of soil to facilitate the evaporation process.
Excavation is accomplished by digging up waste or contaminated soil with either a dragline
unit or a backhoe. i
Extraction Wells are used to remove groundwater for treatment, subsequent discharge, or both.
A well system uses one or more pumps to draw groundwater to the surface forming a cone of
depression in the groundwater table, the extent and slope of which is dependent on pumping rates
and duration as well as local groundwater and soil factors. Groundwater pumping can be used to
lower the water table and to contain a plume. It can also be utilized in conjunction with other
groundwater controls to maximize their efficiency.
Extraction Trenches may be used to collect leachate or shallow groundwater by excavating
trenches that are either equipped with pumps or use gravity to collect contaminated water.
Fixation-see Stabilization.
Groundwater pumping techniques involve the active manipulation and management of ground-
water in order to contain or remove a plume or to adjust groundwater levels in order to prevent
formation of a plume. Groundwater pumping uses a series of wells to remove groundwater for
treatment, subsequent discharge, or both. A well system uses one or more pumps to draw ground-
water to the surface forming a cone of depression in the groundwater table, the extent and slope of
which is dependent on pumping rates and duration as well as local groundwater and soil factors.
Groundwater pumping can be used to lower the water table and to contain a plume. It can also be
utilized in conjunction with other groundwater controls to maximize their efficiency.
Grout Curtains are fixed underground barriers formed by injecting grout, either particulate
(such as portland cement) or chemical (such as sodium silicate), into the ground through well points.
Grout Injection-see Grout Curtains.
Horizontal Wells have distinct accessibility and waste removal advantages over conventional
vertical wells. They can be used to detect, to monitor, to contain, and to extract subsurface
contaminants.
Hydrolysis is the process of transforming a chemical to another species by breaking a bond
in a molecule so that it will react with water. Hydrolysis can be achieved by the addition of
chemicals, by irradiation, or biologically.
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Incineration combusts or oxidizes organic material at very high temperatures. Emission
control equipment is needed for particulates and products of incomplete oxidation to control
emissions of regulated air pollutants.
Infiltration is a method that allows water to percolate through soils by introducing the water
into the ground through a series of wells or a network of underground perforated piping.
Injection Wells may be used to create groundwater barriers to change both the direction of a
plume and the speed of plume migration. By creating an area with a higher hydraulic head, the
plume can be forced to change direction.
Inorganic Stabilization-see Stabilization.
Interceptor Trenches are excavated and designed to prevent surface water from either entering
or escaping from the surface of a site. This helps prevent additional leachate being formed by
infiltration of surface water. It also limits pathways for migrating contaminants.
Ion Exchange is a reversible interchange of ions between an insoluble salt or resin, in contact
with wastes containing ionic species. In the process, unwanted ionic species, principally inorganics,
are replaced ( exchanged) with innocuous ions on the resin. The ion exchange process is used to
treat metal wastes including cations and anions. It is based on the use of specifically formulated
resins having an exchangeable ion bound to the resin with a weak ionic bond.
Land Farming involves the mixing or dispersion of wastes into the upper zone of the soil-plant
system with the objectives of microbial stabilization, adsorption, and immobilization.
Microbial Degradation-B ioremediation.
Neutralization is a process used to adjust the Ph of a waste stream to an acceptable level for
discharge, usually between 6.0 and 9.0 pH units. Adjustments of the pH is done by adding acidic
reagents or acidic wastes to alkaline streams and vice versa.
Oil/Water Separation can be used to separate two (or more) immiscible liquids having
sufficiently different densities, such as oil and water. Liquid/liquid separation occurs when the
liquid mix is allowed to settle. Thus, flow velocities must be kept low. This treatment is applicable
to the insoluble phase only. Another treatment must be used to treat the dissolved phase.
Oxidation reactions are utilized to change the chemical form of a hazardous material in order
to render it less toxic or to change its solubility, stability, separability, or otherwise change it for
handling and disposal purposes. Oxidation can be an effective way of pretreating wastes prior to
biological treatment; compounds that are refractory to biological treatment can be partially oxidized
making them more amenable to biological oxidation. Oxidation rates can sometimes be catalyzed
by ultraviolet light.
Photolysis destroys or detoxifies hazardous chemicals in aqueous solutions using ultraviolet
(UV) irradiation. Adsorption of energy in the UV spectrum results in a molecule's elevation to a
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higher energy state, thus increasing the ease of bond cleavage and subsequent change of the
molecule. Photolysis by .itself is rarely as effective as UV catalyzed oxidation.
Polymerization uses catalysts to convert a monomer or a low-order polymer of a particular
compound to a larger chemical multiple of itself. This technology treats organics and oxygenated
monomers. This treatment is not applicable to soils.
POTW-see Publicly Owned Treatment Works.
Precipitation is a widely used, relatively low cost physical chemical technique in which the
equilibria of chemical constituents of a waste are changed to reduce the solubility of the undesired
components. These components precipitate out of solution and are removed by one or more solids
removal techniques. Precipitation is most commonly used to treat wastes containing heavy metals.
Publicly Owned Treatment Works (POTW) is a facility that furnishes treatment of primarily
municipal wastes. In addition, a POTW oftentimes has the capability to treat selected industrial
wastes, if they are able to meet certain pretreatment standards set by the POTW. A POTW treats
the wastes most often by conventional activated sludge biotreatment.
Pumping Wells-see Groundwater pumping.
Radio Frequency Heating consists of heating a subsurface zone with electromagnetic energy
of varying frequencies to thermally decompose or vaporize hazardous components. The energy is
transmitted to the soil via electrodes placed horizontally above the contaminated area.
Reduction involves addition of a reducing agent which lowers the oxidation state of a
substance in order to reduce toxicity or solubility or to transform it to a form that can be more
easily handled. Most reduction reactions for organic chemicals are done under very dry conditions
because reducing agents often react with water.
Reinjection-see Injection Wells.
Reverse Osmosis removes contaminants from aqueous wastes by passing most of the waste
stream, at high pressure, through a semipermeable membrane. At sufficiently high pressure, clean
water passes out through the membrane leaving a concentrated waste stream that must be treated
further or disposed of. The high pressure counteracts the osmotic pressure of the dissolved wastes
and acts as a driving force to concentrate the solution.
Sheet Pilings are constructed by driving web sections of sheet piling permanently into the
ground. Each section is interlocking at its edges by either a socket or bowl and ball joint. Sections
are assembled before being driven into the ground and initially are not water tight. However, the
joint connections soon fill with fine-to medium-grained soil particles, generally blocking
groundwater flow.
Slurry Walls are fixed underground physical barriers formed by pumping slurry, usually a soil
or cement, bentonite, and water mixture, into a trench as excavation proceeds, and either allowing
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the slurry to set or backfilling with a suitable material. The slurry itself is used primarily to
maintain the trench during excavation.
Soil Aeration introduces air into the soil through mechanical means allowing for a greater air
to constituent surface area. This process increases volatilization but vaporized contaminants must
be withdrawn from the soil in order for this technology to be effective.
Soil Flushing refers to applying a liquid flushing agent to contaminated soil to physically or
chemically remove contaminants. The flushing agent is allowed to percolate into the soil and
enhance the transport of contaminants to groundwater extraction wells for recovery. This technology
is most applicable for soluble organics and metals at a low-to-medium concentration that are
distributed over a wide area.
Soil Pile is a term applied to the biorernediation of soils in an engineered configuration. This
configuration can be a lined excavation in which the soil is replaced and mixed with nutrients. In
addition, a network of perforated piping is added to deliver air once the soil is replaced. Another
configuration is a layer of soil and nutrients, a layer of piping, another layer of soil, etc. in an
aboveground "pile". The pile can be covered over with a liner to reduce emissions.
Soil Vapor Extraction (SVE) has been used to augment groundwater extraction and treatment.
A vacuum is applied to subsurface soils in the unsaturated zone and in dewatered portions of the
saturated zone. The extracted vapor or soil gas contains volatile contaminants that can be either
vented directly to the atmosphere or collected in a vapor-phase carbon adsorption system. The
system may consist of a single extraction well screened in the contaminated zone, or it may include
inlet wells that direct air flow through a particular interval.
Soil Washing is a technology that cleanses the soils of contaminants that are readily removed
by the "solvent" used. Oftentimes, the solvent used is water, but a different solvent, or additives,
can improve the removal efficiency.
Solvent Extraction uses solvents to remove constituents from the groundwater or soil. The
solvent is later recovered, recycled, and reused. Often the extracted soil or groundwater must be
treated further because candidate solvents are environmentally significant materials like petroleum
solvents and chlorinated solvents.
Stabilization processes reduce leachate production by binding waste in a solid matrix by a
physical and/or chemical process. Wastes are mixed with a binding agent and subsequently cured
to a solid form.
Stearn Stripping is an innovative technology used to enhance the volatilization of organic com-
pounds in the soil. Stearn is injected and mixed into the ground through specially adapted hollow
core drill stems. Volatilized organic compounds rise to the surface and are collected via a blower
system. The collected gases are treated to condense the organics and trap the remainder on activated
carbon.
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Stripping removes volatile contaminants from an aqueous waste stream by passing air or steam
through the waste. With air, the volatile, dissolved gases are transferred to the air streams for
treatment such as carbon adsorption. With steam the process is, in essence, a steam distillation of
the waste with volatile contaminants ending up in the distillate for treatment of disposal.
Subsurface Drains are constructed by placing tile or perforated pipe in a trench, surrounding
it with a gravel and backfilling with topsoil of clay.
Surface Water Discharge is a means by which water could be disposed. It involves a
discharge to a stream, river, lake, estuary, bay, ocean, or other body of water.
Thermal Desorption involves heating materials to drive off volatile organics. Thermal desorp-
tion is similar to incineration except it usually operates at a lower temperature and retains the option
of recovering the volatilized chemicals. This process removes volatile organics from soil by heating
the soil in a rotating device while passing a noncombustible vapor through the equipment. The
equipment is often heated indirectly to avoid contact between the combustion gases and the contami-
nated soil. Gas produced by the process is usually treated by condensation, scrubbing, or secondary
combustion.
Vitrification is a thermal treatment process that converts the contaminated area into a
chemically inert, stable glass and crystalline product. Electrodes are inserted into the area to be
treated, and a conductive mixture of flaked graphite and glass frit is placed among the electrodes
to act as the starter path. An electric potential is applied to the electrodes, establishing an electric
current in the starter path. The resultant power heats the starter path and surrounding material above
the fusion temperature of soil. The graphite starter pad is consumed by oxidation, and the current
is transformed to the molten soil.
Wet Air Oxidation (W AO) is a type of chemical reaction initiated through addition of air at
high pressures and elevated temperatures. W AO works well on some wastes that are too concen-
trated for conventional biological treatment because the energy released during the oxidation helps
maintain operating temperatures. W AO is rarely considered for treating groundwater because the
low concentrations of organics will not sustain the reactions.
TM\7200APA.TM
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