NCD986187128_19980826_North Belmont PCE_FRBCERCLA LTRA_Final In Situ Bioremediation Treatability Work Plan-OCR

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REMEDIAL PLANNING ACTIVITIES AT SELECTED
UNCONTROLLED HAZARDOUS SUBSTANCES DI~Posi,~r~
P,E"C
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGe'i~ 9 1998
REGION IV s1:.c1\0N S\JPE.Rf\JND
The data contained in all pages of this proposal have been submitted in confidence and contain trade secrets and/or privileged or confidential. commercial,
. or financial information, and such data shall be used or disclosed only for evaluation purposes provided thaL if a contract is awarded to this proposer as a result
, of or in connection with the submission of this proposal, the Government shall have the right to use or disclose the data herein to the extent provided in the
contract. This restriction docs not limit the Government's right to use or disclose data obtained without ~striction from any source, including the proposer.
FINAL
IN SITU BIOREMEDIA TION
TREAT ABILITY WORK PLAN
FOR THE
NORTH BELMONT PCE SITE
NORTH BELMONT, NORTH CAROLINA
AUGUST 26, 1998
U.S. EPA CONTRACT NO. 68-W9-0056
WORK ASSIGNMENT NO. 076-4RDQD
DOCUMENT CONTROL NO. 7740-076-WP-BTBC
Angela Luckie /
Project Manager
Approved By: ..1.U=1.;;G:1;~~~.d::· ~' =-~:;e=E..;~:=;IGt:t::·?!...r_
G z ary P. C_lemons, Ph.D.
Program Manager
Prepared by:
COM FEDERAL PROGRAMS CORPORATION
2030 Powers Ferry Road. Suite 490
Atlanta, Georgia 30339
ARCS REGION IV
Date:
Date:
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TABLE OF CONTENTS
Section
1.0 INTRODUCTION ....................................................... 1-1
I.I PROJECT PURPOSE AND SCOPE ..................................... 1-1
1.2 SUMMARY OF SITE CERCLA HISTORY ............................... 1-1
1.2.1 REMEDIAL INVESTIGATION SUMMARY ...................... 1-2
1.2.2 RISK ASSESSMENT AND RISK CHARACTERIZATION
SUMMARY ................................................. 1-4
1.2.3 RECORD OF DECISION SUMMARY ............................ 1-4
1.2.4 PERFORMANCE ST AND ARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.3 CONTAMINANT FATE AND TRANSPORT MECHANISMS ............... 1-6
1.3.1 HYDROGEOLOGIC PARAMETERS ............................ 1-7
1.3.2 UNDERSTANDING BIOLOGICAL SYSTEMS .................... 1-9
1 .4 PRELIMINARY SITE CONCEPTUAL MODEL .......................... 1-12
1.4.1 SITELOCATIONANDDESCRIPTION ......................... 1-13
1.4.2 SITE GEOLOGY ............................................ 1-14
1.4.3 SITE HYDROGEOLOGY ..................................... 1-19
1.4.4 EXISTING GROUNDWATER MONITORING WELLS ............. 1-22
I .4.5 EXTENT OF CHLORJNATED ALIPHATIC HYDROCARBON
CONTAMINATION ......................................... 1-23
1.4.6 EVIDENCE OF BIOLOGICAL PROCESSES ..................... 1-36
1.4.7 DATA NEEDS .............................................. 1-36
2.0 UNDERSTANDING ENHANCED IN SITU BIOREMEDIATION ................ 2-1
2.1 HISTORY OF IN SITU BIOREMEDIATION ............................. 2-1
2.2 DESCRIPTION OF TECHNOLOGY .................................... 2-I
2.3 APPROACH TO EVALUATING ENHANCED ANAEROBIC
BIODEGRADATION ................................................ 2-3
2.4 OBJECTIVES ...................................................... 2-5
3.0 PHASE I-FIELD CHARACTERJZA TION .................................. 3-1
3.1 OVERVIEW AND APPROACH ........................................ 3-1
3.2 SAMPLING AND ANALYSIS PLAN ................................... 3-1
3.2.1 SELECTION OF GROUNDWATER MONITORING WELLS ......... 3-1
3.2.2 ANALYTE SELECTION ....................................... 3-2
3.2.3 DATA QUALITY OBJECTIVES ................................ 3-6
3.2.4 MONITORING WELL INSTALLATION ......................... 3-6
3.2.S WELL DEVELOPMENT ....................................... 3-7
3.2.6 FIELD INSTRUMENT CALIBRATION AND MAINTENANCE ...... 3-8
3.2.7 SAMPLING METHODS AND EQUIPMENT ...................... 3-8
3.2.8 SAMPLE IDENTIFICATION ................................... 3-9
3.2.9 FIELD QUALITY CONTROL PROCEDURES .................... 3-10
3 .2.10 SAMPLE CUSTODY ......................................... 3-11
3 .2.11 SAMPLE PACKING AND SHIPPING ........................... 3-11
3.2.12 DATA VALIDATION ........................................ 3-11
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3.2.13 DOCUMENTATION ......................................... 3-12
3.2.14 DECONTAMINATION PROCEDURES .......................... 3-16
3.2.15 WASTE HANDLING ........................................ 3-17
3.2.16 QUALITY ASSURANCE/QUALITY CONTROL .................. 3-18
3 .2.1 7 HEAL TH AND SAFETY ...................................... 3-18
3.3 TASK I-DATA REVIEW ........................................... 3-18
3.4 TASK 2-SAPROLITE AQUIFER CHARACTERJZA TION ................ 3-19
3.4.1 SUBTASK I-DELINEATION OF GROUNDWATER
CONTAMINANT PLUME .................................... 3-19
3.4.2 SUBTASK 2-SELECTION OF MONITORING WELL
LOCATIONS ........ , ...................................... 3-21
3.5 TASK 3-SAMPLE ACQUISITION AND HANDLING ................... 3-21
3.6 TASK4-GROUNDWATER WELL INSTALLATION ................... 3-21
3.6.1 SELECTED LOCATIONS ..................................... 3-21
3.6.2 SOIL BORING AND VERTICAL PLACEMENT SELECTION ....... 3-22
4.0 IN-WELL AIR STRIPPING ............................................... 4-1
4.1 DESCRIPTION OF TECHNOLOGY .................................... 4-1
4.2 PRESENTATION OF VENDOR SUBMITTALS ........................... 4-1
4.3 EVALUATION OF VENDOR SUB MITT ALS ............................ 4-8
5.0 REFERENCES .......................................................... 5-1
APPENDIX A: IN-SITU VAPOR STRJPPING VENDOR INFORMATION ........... A-I
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LIST OF FIGURES
Figure Page
1-1 North Belmont PCE Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1-2 Site Location Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1-3 Cross-Section Base Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 5
1-4 Geologic Cross-Section A-A' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
1-5 Geologic Cross-Section B-B' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
1-6 Geologic Cross-Section C-C' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
1-7 Saprolite Aquifer. Potentiometric Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
1-8 Bedrock Aquifer, Potentiometric Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 I
1-9 Shallow Groundwater Plume, PCE Contamination ........................... 1-26
1-10 Shallow Groundwater Plume, TCE Contamination ........................... 1-27
1-11 Shallow Groundwater Plume, DCE Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28
1-12 Top of Bedrock Groundwater Plume (Temporary Wells and Permanent Wells),
PCE Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29
1-13 Top of Bedrock Groundwater Plume (Temporary Wells and Permanent Wells),
TCE Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
1-14 Top of Bedrock Groundwater Plume (Temporary Wells and Permanent Wells),
cis-1,2:ocE Contamination ............................................. 1-31
1-15 Bedrock Groundwater Plume (Bedrock MW and Potable Wells),
PCE Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33
1-16 Bedrock Groundwater Plume (Bedrock MW and Potable Wells),
TCE Contamination ................................................... 1-34
1-17 Bedrock Groundwater Plume (Bedrock MW and Potable Wells),
cis-1,2-DCE Contamination ............................................. 1-35
LIST OF TABLES
Table
1-1 Performance Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1-2 Monitoring Wells Specifications ......................................... 1-24
1-3 Screening Results for Electron Acceptors/Metabolic Byproducts and Nutrients .... 1-37
3-1 Existing Groundwater Monitoring Wells and Residential Wells Selected
for Sampling .......................................................... 3-2
3-2 Sampling Requirements and Analytical Methods ............................. 3-3
4-1 Summary of Vendor Supplied Cost Estimates for Pilot Testing .................. 4-2
4-2 Evaluation ofln Situ Technologies ........................................ 4-9
98-035n740-076I0824 IV
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1.0 INTRODUCTION
1.1 PROJECT PURPOSE AND SCOPE
A feasibility study conducted by the U.S. Environmental Protection Agency (USEPA) in July 1997
(USEPA 1997a) evaluated remedial alternatives for the North Belmont PCE Superfund Site (Site)
in North Belmont, North Carolina. In-well vapor stripping and enhanced in situ bioremediation were
selected as the groundwater cleanup remedial actions. Documentation of this decision is contained
in the Record of Decision (ROD) (USEPA 1997b).
This work plan is the first part of a multi-phased approach to evaluate the applicability of currently
available technologies for remediation of tetrachloroethene (PCE) contaminated groundwater
specifically for the Site. Phase I consists of the preparation of an enhanced in situ bioremediation
treatability study work plan and the summary of preliminary designs and cost estimates from in-well
vapor stripping vendors. This work plan focuses on the identification of the initial bioremediation
approach and resultant data needs that must be filled to determine if enhanced bioremediation is
likely to accelerate the rate of groundwater contaminant removal. The technical approaches and cost
estimates provided by in situ vapor stripping vendors are also included in the work plan.
Preliminary evaluation of bioremediation options for the Site indicates that enhanced anaerobic
(without oxygen) bioremediation is currently the most applicable biotechnology. This is an
innovative and new technology and the implementability will be determined in a laboratory study
and field demonstration. However, in situ vapor stripping, the selected groundwater remedy, will
increase the dissolved oxygen content in the treated groundwater, which may be counterproductive
to anaerobic processes. Aerobic biological treatment will also be considered should anaerobic
processes be incompatible with companion technologies.
1.2 SUMMARY OF SITE CERCLA HISTORY
In February 1991, the Gaston County Health Department sampled the well that provided water to
the North Belmont Elementary School and two single family dwellings. This sampling was
associated with an effort by the County to evaluate community water supplies for volatile organic
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compound (VOC) contamination. The results of this sampling indicated significant VOC
contamination in the well. USEPA Region IV Emergency Response was notified. USEPA and the
Gaston County Health Department sampled 25 drinking water wells. PCE, trichloroethene (TCE),
and cis-1,2-dichloroethene ( 1.2-DCE) were detected in sixteen samples. The elementary school was
immediately connected to the City of Belmont water system. Twenty-nine of the neighborhood
drinking water wells were taken out of service and connected to the Belmont city water system.
Seven residences in the neighborhood were informed of the contamination but chose to continue to
use their wells and not connect to city water. Wells still in use in the vicinity of the Site were not
sampled until USEPA's investigation in 1996.
1.2.1 REMEDIAL INVESTIGATION SUMMARY
A Remedial Investigation (RI) was conducted by USEPA to determine the nature and extent of
contamination at the Site (USEPA 1997c). The extent of chlorinated aliphatic hydrocarbon (CAH}
contamination is discussed in detail in Section 1.3.4; however, the following briefly summarizes
conclusions from the RI Report:
I. The contaminant plume is spreading. Private wells in the vicinity of the Site that were not
contaminated in 1991 when USEPA first investigated the Site are now contaminated.
2. Contamination detected in the shallow aquifer appears to be localized in Source Area A (Ropers
Shopping Center). See Figure 1-1 for source area locations.
3. Contaminants have migrated from the shallow aquifer into the top of bedrock zone and into the
bedrock aquifer. Maximum PCE concentrations detected in the saprolite aquifer, the top of
bedrock aquifer, and the bedrock aquifer during the 1996 RI sampling were 2200 µg/L,
2500 µg/L, and 3500 µg/L, respectively.
4. The source of contamination in the southern edge of the plume may be either Source Area A
or Source Area B.
5. Neither source area contains residual soil volatile organic contamination. It is believed that the
contaminants migrated through the soil directly into the shallow aquifer. VOCs in surface soil
evaporated.
6. Surface water and sediment in the area are not affected by the VOCs.
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SOURCE AREA
./(.,i., ,. ·-v,....._ .. : .. • ;.··
/ ..,___;. :_ ... ·· -. .~-··•·; . .
.::::::-, .·
·:.:·:,:•.•,¥:::::·;
. '.\:_.c/i\{/f .. ~ .
I ·-; .-··
SOURCE: DeLORME MAP EXPERT
cmt FEDERAi.ARCS fV
SITE LOCATION MAP
NORTI-1 BELMONT PCE SUPERFUND SITE
NOTE: NOT TO SCALE
FIGURENO.
1-1
~ NORTI-1 BELMONT, NORTI-1 CAROLINA a.,_ __________________________ ,._ ___ _
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1.2.2 RISK ASSESSMENT AND RISK CHARACTERIZATION SUMMARY
A summary of the findings of the Baseline Risk Assessment relevant to groundwater is presented
here. An in-depth discussion of the risk assessment findings is contained in the RI Report (US EPA
1997c).
The following were identified as chemicals of potential concern in groundwater: PCE, TCE,
cis-1,2-DCE, 1, 1-dichloroethene (I, 1-DCE), 1,4-dichlorobenzene (1,4-DCB), trichlorofluoro-
methane (TCFM), methylene chloride (MC), chloroform (CF), bis(2-ethylhexyl)phthalate, alpha-
chlordane, gamma-chlordane, heptachlor epoxide, aluminum, cadmium, chromium, lead,
manganese, and zinc.
The following were identified as chemicals of potential concern in soil: benzo(a)pyrene,
benzo(b and/or k)fluoranthene, benzo(a)anthracene, dibenzo(a,h)anthracene, indeno( 1,2,3-cd)pyrene,
aluminum, chromium, manganese, and vanadium.
Future use scenarios relevant to exposure assessment considered construction of a water supply well
within the groundwater contaminant plume and ingestion of soil, inhalation of dusts, and dermal
contact with soils as a worse-case scenario. Possible exposure pathways for groundwater included
exposure to contaminants of concern from the groundwater plume in drinking water and through
inhalation of volatiles evolved from water through household water use. The results of the risk
assessment and the risk characterization, based upon the assumption that water from the center of
the plume would be used for drinking and showering, indicated that the primary risk was caused by
PCE, with a smaller but significant contribution from cis-1,2,-DCE.
1.2.3 RECORD OF DECISION SUMMARY
The USEPA ROD for the Site recommended that the groundwater remedy consist of the following:
connection of all homes, churches, and business in the "North Belmont PCE Area"
depicted in Figure 1-2 to the public water supply;
98-035/7740.076/0824 1-4
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' V.
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42 LOT NUMBERS
ti PREVIOUS ORV CUANING fACIUTtES
.A. PREVIOUS RffRIGfRATOR REPAR FMlUIY
l!I WCHINESHOP
SCALE = 500
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< IN fEET )
IICH = 500 fEET
cou-
.. ..
COM FEDERAL ARCS IV
NORTiiBELMONTPCEAREA
NORTH BELMONT PCE SUPERFUND SITE
NORTii BELMONT, NORTii CAROLINA
., __ ,, __ _
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FIOURENO.
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1.2.4
optional installation of carbon filters on private wells at homes that did not opt to connect
to the public water system, including one year of filter operation and maintenance, and
filter replacement after one year; and
groundwater treatment via in-well vapor stripping and in situ bioremediation.
PERFORMANCE STANDARDS
The goal of this remedial action is to restore the groundwater to its beneficial use. Based on
information obtained during the RI and the analysis of all remedial alternatives, USEPA and the state
of North Carolina believe that the selected remedy will be able to achieve this goal. The
performance standards for groundwater cleanup are listed in Table 1-1.
Table 1-1
Performance Standards
Contaminant Remediation Level
Lead 15 µg/L
Methylene Chloride 5 µg/L
Cis -1,2-Dichloroethene 70 µg/L
Trichloroethene 2.8 µg/L
Tetrachloroethene I µg/L
Bis(2-ethylhexyl)phthalate 3 µg/L
Chlorofonn I µg/L
I, 1-Dichloroethene I ""'L
1.3 CONTAMINANT FATE AND TRANSPORT MECHANISMS
Identified in the RI Report (USEPA 1997c), and discussed in minimal detail, are potential routes of
contaminant migration, chemical properties of contaminants of concern, and biotic and abiotic
mechanisms that may affect the fate and transport of contaminants. This section provides more
detailed background information on processes that influence the fate and transport of Site
contaminants, and data requirements for quantification of such processes. The significance of these
processes will be quantified with completion of tasks outlined in this Treatability Work Plan.
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1.3.1 HYDROGEOLOGIC PARAMETERS
Historical data may sufficiently define some of the following hydrogeologic parameters. These
properties must be defined to help model contaminant fate and transport. In addition, quantification
of the following hydraulic parameters will assist in determining which of the considered remedial
technologies may be economically or technically feasible.
Groundwater Flow Directions: Vertical and horizontal groundwater migration patterns should be
better defined where possible to delineate flow paths into and away from apparent source areas
potentially causing contaminant migration through the three water-bearing zones.
Seepage Velocity (Vs): Seepage velocity is the actual interstitial groundwater velocity. It is
calculated by multiplying hydraulic conductivity by the hydraulic gradient and dividing by effective
porosity. Estimates of hydraulic conductivity, hydraulic gradient, and effective porosity have been
estimated and should be verified at various locations throughout the site.
i. Hydraulic Conductivity (K): Hydraulic conductivity is a measure of an aquifer's
ability to transmit water, and is perhaps the most important aquifer parameter governing
fluid flow in the subsurface. Site-specific hydraulic conductivities have been estimated
using slug tests and should be verified at various locations throughout the site during
future field activities.
ii. Hydraulic Gradient (dh/dl): Hydraulic gradient is the slope of the potentiometric
surface. In unconfined aquifers, this is equivalent to the slope of the water table.
Hydraulic gradients may be estimated from potentiometric surface water maps using static
water level data from monitoring wells.
iii. Effective Porosity (n): Effective porosity is a dimensionless ratio of the volume of
interconnected voids to the bulk volume of the aquifer matrix. Typical values are often
estimated based upon the stratigraphy. Stratigraphic information is also needed to
determine if preferential flow paths ( e.g., sand lenses, fill material) exist.
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Contaminant Retardation: The retardation of organic solutes caused by adsorption is an important
consideration when estimating contaminant migration rates. The degree of retardation depends on
both aquifer and constituent properties. Usually the retardation factor, R, is estimated using soil
bulk density, effective porosity, organic carbon partition coefficient, and fraction of organic carbon.
These data are needed for all three aquifer zones.
i. Soil Bulk Density (p,): The bulk density ofa soil expresses the ratio of the mass of
dried soil to its total volume (solids and pores together). Values for soil bulk density
should either be estimated from a geotechnical lab analysis of soil samples or assigned an
estimated value.
ii. Organic Carbon Partition Coefficient (K,J: The organic carbon partition coefficient
is the chemical-specific partition coefficient between soil organic carbon and the aqueous
phase. Chemical-specific values are available in reference literature. K00 values can also
be calculated based on the octanol-water partition coefficient or solubility of the
compound of concern.
iii. Fraction of Organic Carbon (f00): The fraction of organic carbon is the fraction of
the aquifer soil matrix comprised of natural organic carbon in uncontaminated areas.
More natural organic carbon means higher adsorption of organic constituents on the
aquifer matrix. Values should be measured by collecting a sample of aquifer material
from a background zone and performing a laboratory analysis. The f00 multiplied by the
K00 will yield the distribution coefficient (K.,) necessary to calculate retardation.
Dispersivity (a): Dispersion refers to the process whereby a contaminant spreads out in a
longitudinal direction (along the direction of groundwater flow), transversely (perpendicular to the
groundwater flow), and vertically downwards due to mechanical mixing in the aquifer and chemical
diffusion and/or vertical gradients. These values should be estimated as a function of plume length.
Effect of Recharge: Area-specific surface recharge and subsequent vertical migration rates should
be determined, where possible, via continuous water level measurements with in-well transducers.
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Surface recharge should be controlled in areas more sensitive to infiltration or generally across the
site.
1.3.2 UNDERSTANDING BIOLOGICAL SYSTEMS
Biological processes are typically the most important processes influencing the fate and transport
of contaminants in the environment. Biodegradation may occur under a wide array of environments
with varying geochemical parameter distributions and microbial communities. Biodegradation
refers to the process in which contaminants are fully degraded to innocuous end-products such as
carbon dioxide and water. In contrast. biotransforrnation of contaminants generally refers to the
process in which contaminants are incompletely biodegraded to daughter products. Thus,
biotransformation processes do not ensure a reduction in toxicity. Many of the daughter products
of biotransformation processes are as toxic, or more toxic, than their parents. For example,
biotransforrnation of TCE can stop at vinyl chloride (YC), which is more toxic than the parent
compound.
The mechanisms that contribute to the biological attenuation of contaminants require
microorganisms that produce energy to drive their cellular activities, including growth and
maintenance. The energy production process involves the transfer of electrons from donor
compounds to acceptors. The result is the oxidation of an electron donor and reduction of an
electron acceptor. For thermodynamic (energetic) reasons, microorganisms preferentially use those
electron acceptors that provide the greatest amount of free energy during respiration and will
facilitate only those redox reactions that will yield energy.
Typical electron donors in aquifers are naturally occurring organic (carbon-containing) compounds
such as humic acid or contaminants and petroleum hydrocarbons or domestic sewage. Since the
transfer of electrons from these organic compounds takes place during their metabolism, they must
be biodegradable under the local environmental conditions to serve as an electron donor. Certain
inorganic compounds can also serve as electron donors: under aerobic conditions ammonium,
nitrite, ferrous iron, and sulfide ions can donate electrons and under anaerobic conditions molecular
hydrogen is an important electron donor.
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A relatively small number of compounds can serve as electron acceptors. Since the reaction in
which these compounds accept electrons involves the release of energy, electron acceptors are used
"in a sequence according to the amount of energy provided to the cell. The order in which common
electron acceptors are used is: oxygen, nitrate, ferric iron, sulfate, and finally carbon dioxide
(methanogenesis). As each of these is used in turn, the local environment becomes more reducing,
as evidenced by a lower redox potential. This is illustrated in the typical hydrocarbon contamination
plume in which the fringes are aerobic and have a high redox potential, while the core is anaerobic
with a much lower redox potential. Thus, microbial activity has a strong impact on the redox
potential of a site.
The oxidation of these electron donors can be described by stoichiometric equations. In the
following equations, the chemical structure for benzene (C6H6) is used as a representative electron
donor, and microbial growth is neglected for simplicity. In order of most oxidizing to most reducing
conditions, the equations are:
Aerobic Respiration (electron acceptor: oxygen)
Gibb's Free Energy of the Reaction = -3,202 kJ/mole
C6H6 • 7.5 0 2 -6 CO 2 , 3 H,0
Denitrification (electron acceptor: nitrate)
Gibb's Free Energy of the Reaction = -3245 kJ/mole
c,H, • 6 No; • 6 H" -6 co, . 6 H,o • 3 N,
Iron (III) Reduction (electron acceptor: ferric iron)
Gibb's Free Energy of the Reaction = -2343 kJ/mole
C6H6 , 60 H" • 30 Fe(OH)3 -6 CO 2 • 30 Fe 2•• 78 H 20
Sulfate Reduction (electron acceptor: sulfate)
Gibb's Free Energy of the Reaction = -514 kJ/mole
C6H6 • 1.5 w. 3.75 so.'" -6 co,. 3.75 H2s. 3 H2o
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Methanogenesis ( electron acceptor: carbon dioxide)
Gibb's Free Energy of the Reaction = -136 kJ/mole
c.H. • 4.5 H,o -2.25 co,• 3.75 CH 4
Each of the above reactions is mediated by different microbial populations, referred to by the type
of energy metabolism they use (e.g., denitrifiers, methanogens, etc.). Another important group of
bacteria is the fennenters, which use organic compounds as both electron acceptors and donors. In
the process, they produce molecular hydrogen that can be used by other anaerobes (sulfate reducers
and methanogens) as an electron donor. This is an important reaction in the biodegradation of
chlorinated solvents. Hydrogen is used in the dechlorination process of many of these compounds.
Understanding the basic means by which microorganisms affect groundwater redox conditions is
critical to analysis of biodegradation mechanisms. Investigations conducted under both field and
laboratory conditions indicate that chlorinated solvents can be biotransfonned under different redox
environments. Biotransfonnation can occur via co-metabolism under both aerobic and anaerobic
conditions, via reductive dechlorination under anaerobic conditions,_ or via oxidation under aerobic
or iron reducing conditions.
The biodegradation of chlorinated solvents found at the Site primarily occurs under anaerobic
conditions via reductive dechlorination mechanisms. Reductive dechlorination involves the growth
of microorganisms on an organic compound (i.e., electron donor) in which chlorinated solvents serve
as the electron acceptor. As a result, chlorinated solvents are biotransfonned through microbially-
mediated, sequential dechlorination processes. The following reaction sequence depicts the
reductive dechlorination of PCE to non-toxic ethene and ethane:
PCE -TCE -cis-1,2-DCE -VC -ethenelethane
The above sequence tenninates at ethene and ethane (i.e., non-toxic products) under anaerobic
conditions; however, these compounds readily biodegrade under aerobic conditions to carbon
dioxide and water. VC is also known to biodegrade under iron reducing conditions (anaerobic) to
carbon dioxide, when ferric iron is biologically available (Bradley and Chapelle 1997). Although
the biodegradation of chlorinated solvents primarily occurs under anaerobic dechlorination
98-0J5n740-076t0&24 1-11
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conditions, recent research indicates that VC rapidly biodegrades under aerobic conditions to carbon
dioxide and water (Bradley and Chapelle 1998). Furthermore, recent evidence suggests that cis-1,2-
DCE also biodegrades under aerobic conditions to carbon dioxide and water. Although more
research on this subject is needed. this is an important reaction for consideration at the Site.
The extent and rate at which chlorinated solvents are biotransformed to less chlorinated compounds
is highly dependent upon the redox potential of a site and the degree of chlorination. In general, the
reductive dechlorination of chlorinated solvents requires highly reducing conditions. The rate of
dechlorination generally increases as the environment becomes more reducing, with the fastest
dechlorination rates occurring under methanogenic conditions. Furthermore, the rates of
dechlorination generally decrease as the degree of chlorination decreases (i.e., TCE dechlorination
is faster than cis-1,2-DCE, etc.). The redox potential is greatly affected by the availability of readily
biodegradable organic matter (i.e., electron donor), the type of microbial consortia present, and the
available electron acceptor levels. Electron donor availability is critical in determining the extent
and rate at which reductive dechlorination reactions occur. Oxidative biodegradation of applicable
chlorinated solvents (e.g., cis-1,2-DCE and VC) is generally a much more rapid process than
reductive dechlorination.
Thus, the extent and rate of dechlorination reactions is dependent upon four factors. These factors
include: (I) the availability of sufficient electron donor, (2) the presence of competing electron
acceptors, (3) the groundwater redox conditions, and (4) the microbial consortia present. Once these
factors have been evaluated, microcosm studies can be performed to determine whether the extent
and rate of dechlorination reactions may be enhanced and the necessary amendments for achieving
the optimal enhancement.
1.4 PRELIMINARY SITE CONCEPTUAL MODEL
The following preliminary site conceptual model has been developed to document our current
understanding of the Site. This preliminary model will help determine the feasibility of remedial
technologies, identify current data gaps, and assist in the development of future field activities. The
information in this section has been excerpted from the North Belmont PCE Site Remedial
98-03 5n740-0161os24 1-12
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Investigation (RI) Report (USEPA 1997c), the North Belmont PCE Site Feasibility Study Report
(USEPA 1997a), and additional data sources.
Documented in the RI Report (USEPA 1997c). previous site investigations conducted by USEPA
Science and Ecosystem Support Division (SESD) and Weston involved installation of shallow and
deep soil borings, shallow temporary monitoring wells, top of bedrock temporary monitoring wells,
and permanent top of bedrock and bedrock monitoring wells at various site locations. Slug testing
and geophysical borehole logging activities were conducted at select wells. Soil and groundwater
samples were collected at these locations, as well as residential well locations. These activities were
conducted to: evaluate the extent and distribution of contamination in soils and groundwater;
identify likely source regions or "hot spots"; help characterize the site geology and hydrogeology;
and obtain a preliminary understanding of contaminant fate and transport mechanisms. Findings
from these activities are summarized in the following sections.
l.4.1 SITE LOCATION AND DESCRIPTION
The Site consists of two closed dry cleaning operations located in North Belmont, Gaston County,
North Carolina. These two areas are referred to as "Source Area A" and "Source Area B"
(Figure 1-1). Source Area A, which was operated by the Untz family from 1960 to 1975 as a dry
cleaning business, is located at Roper's Shopping Center in Land Lot 5, Parcel 15-18A on
Woodlawn Avenue. The shopping center includes Roper's Furniture Store, a Baptist church, and
a cabinet manufacturing shop. The former dry cleaning facility is approximately 0. 75 acre in size
and is bounded to the east and west by residential neighborhoods, to the north by a cemetery and an
undeveloped wooded tract, and to the south by North Belmont Elementary School. Source Area B
is located at the northeastern comer of Acme Road and Suggs Road in Land Lot 11, Parcel 15-18.
This parcel has been converted to residential property. The majority of the area surrounding Source
Area Bis residential with a few small businesses. A cabinet shop is.located to the north. A previous
refrigerator repair shop and a machine shop were also suspected to be potential sources of
contamination. The refrigerator repair shop, now closed, is located at the intersection of Julia Street
and Acme Road in land lot 15-1 SA, Parcel 32. This is a small commercial strip area with residential
property surrounding the Site, except for a cabinet shop and a well drilling company located to the
98.035/7740-076/0824 1-13
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east. The machine shop is located at the comer of Acme and Centerview Roads and is encompassed
by residential neighborhoods. Figure 1-2 shows the approximate study area.
1.4.2 SITE GEOLOGY
The Site is located within the central portion of the Charlotte Belt of North Carolina. The rock types
that underlie this terrain are dominated by granitic type rocks, metavolcanics, and gneisses and
schists of varying types. The rock types are of varying metamorphic grade and all rock units trend
parallel with the strike of the Appalachian Mountains, which is typically northeast to southwest.
These same units typically dip to the southeast along with the regional topographic trend.
Structurally. the area is complex with rock units displaying one or two types of metamorphism or
structural changes such as faulting or folding. A large, unnamed fault is located approximately
six miles to the west of the Site.
According to the Geologic Map of North Carolina ( 1985), the Site is underlain by foliated to
massive metamorphosed quartz diorite and massive to weakly foliated, hornblende rich granitic type
rock. These rock units have undergone periods of deformation that have produced folding and
fracture planes in the rock, as well as brittle zones where the rock is actually crushed, sheared, or
faulted in some manner. As these rock types become weathered, soil profiles develop that are
characteristic of the original rock (also referred to as saprolite).
During the field activities, the soil profile varied with each location; however, a common pattern was
observed. From top to bottom, the materials consist of a saprolite layer, a partially weathered rock
zone, and the underlying fractured crystalline bedrock. Figures 1-3 through 1-6 present cross-
sectional views of the saprolite and bedrock lithologies. The saprolite is clay-rich, residual material
derived from in-place weathering of bedrock. Typically, the saprolite is silty clay near the surface.
With increasing depth, the amount of mica, silt, and fine-grained sand and gravel tend to increase.
Remnant fracture planes with quartz infilling appear in this layer. The saprolite zone is thickest
(approximately 125 feet) along the ridgeline on the western edge of the Site, thinning towards the
lower elevations or stream valleys to approximately 30 feet in thickness. Underlying the saprolite
is a partially weathered rock layer derived from the weathering of bedrock and ranges in thickness
98-03S/77 40-076/0824 1-14
- -- - -- --
LEGEND
SECTION l.mE LOCAnOtJ
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CROSS-SECTIOM BASE MAP
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CROSS-SECTION BASE MAP, AUGUST 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUND SITE NORTH BELMONT, GASTON COUNTY, NC
SESD PROJECT No. 96S-058, JUNE 1997
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GEOLOGIC CROSS-SECTION A-A'. AUG 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUblD SITE
NORTH BELMONT, GASTON cou1,1Y. NC
SESD PROJECT No. 965-058, JUNE 1997
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GEOLOGIC CROSS-SECTION B-B', AUG 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUND SITE
NORTH BELMONT, GASTON COUl~TY. '"C
SESD PROJECT No. 96S-058, JUNE ·1997
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FIGURE 1-6 ~E ~--~ GEOLOGIC CROSS SECTION C-C', AUG 1996 i REMEDIAL INVESTIGATION REPORT
j NORTH BELMONT PCE SUPERFUND SITE
NORTH BELMONT, GASTON COUNTY, NC
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from approximately IO to 50 feet. This layer is composed of saprolite and fragments of weathered
bedrock. Particle sizes range from silts and clays to large boulders of unweathered bedrock. The
weathering occurs in bedrock zones less resistant to physical and chemical degradation (i.e., fault
zones, stress relief fractures. and mineralogic zones). The predominant rock types appear to be
metamorphosed quartz diorite and metamorphosed granite or granitic gneiss. The bedrock is
fractured and these fractures contain quartz deposits that remain unweathered in the saprolite and
therefore are likely to act as confining layers.
1.4.3 SITE HYDROGEOLOGY
Regionally, the water bearing units that underlie the Site and surrounding areas represent an aquifer
system consisting of metamorphosed and fractured quartz diorite and granitic type rocks in varying
proportions and thicknesses. Geologic structures that produce high-yielding wells include contact
zones of multi layered rock units, zones of fracture concentration, and stress-relief fracture zones.
According to LeGrand and Mundorf[ ( 1952), wells in Gaston County that are set within granite have
an average depth of 165 feet and an average yield of 18 gallons per minute. Within this area,
LeGrand and Mundorff indicate that well depths range from 85 to over 1,000 feet and that well
yields range from 2½ to 116 gallons per minute. The aquifer system underlying the Site generally
consists of the saprolite/partially weathered rock aquifer and the underlying bedrock aquifer;
however, interconnection between these units is likely, thereby influencing contaminant transport.
Aquifer designations used during the RI for the Site are the saprolite aquifer, the top of bedrock
aquifer, and the bedrock aquifer. These same designations apply to this Work Plan.
In the Site area, the top of the water table is typically found in the saprolite aquifer and will
generally mimic the overlying land surface. The depth to water across the area ranges from
approximately 3 to 35 feet below ground surface. Based on groundwater elevations collected in
November 1996 and potentiometric maps drawn from these elevations, groundwater within the
saprolite (Figure 1-7) and bedrock (Figure 1-8) aquifers generally flows to the northeast to east
across the Site. Furthermore, Roper's Shopping Center appears to be positioned within the top of
a localized groundwater mound with potentiometric contours emanating in a semi-circular pattern
from this point. Insufficient data of groundwater elevations along the western edge of the Site
prevent completion of the potentiometric contours.
98-035/7740-076/0824 1-19
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--
FIGURE 1-7. ~ E·. Pi~ SAPROLITE AQUIFER, POTEMTIOMETRIC MAP ,_.., OCTOBER 1996
\ REMEDIAL INVESTIGATION REPORT
I NORTH BELMONT PCE SUPERFUl~D SITE
, NORTH BELMONT, GASTON COUNTY, NC
s.,_ _______ ~--------~--------------J1-. _____________ s_E_so_r-R_o_J_E_c_T_N_o_. _9_6_s_-_o_s_s__. _J-LJ__N __ ~----1~9-9_7..J
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~ NORTH BELMONT PCE SUPERFUND SITE
, NORTH BELMONT, GASTON COUNTY, NC ''-----------------·~··--··~·~-·----~------------_jL ____________ :s:.ES:.:D::...;P.;.R::.O::J::E.:C::T~N::o:.. . .:9:::6:::s_-:.o::5:8:.., :.J::U:l"'.::E.....'.1:9:97:_j
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Based on depth-to-water measurements for monitor wells MW-13 and MW-21, groundwater
discharges from the saprolite and bedrock aquifers into the small stream along the northern edge of
the Site: however, fractures present in the partially weathered rock and bedrock will affect the
direction of groundwater flow, and relict fractures present in the saprolite may also control
groundwater flow directions. According to Harned ( 1989), most of the natural flow in the bedrock
system is probably confined to the upper 30 feet of bedrock where fractures are concentrated, and
the overlying transition zone which has the highest hydraulic conductivity.
Data were collected during the 1996/1997 RI for estimating hydraulic gradient and hydraulic
conductivity at the Site. The hydraulic gradients for the saprolite and bedrock aquifers were
calculated to be 0.0298 and 0.0275, respectively. Data from rising-head slug tests were used to
calculate hydraulic conductivity in the saprolite and bedrock aquifers. The resultant values ranged
from 0.24 to 1.99 ft/day in the saprolite aquifer and 0.016 to 3.41 ft/day in the bedrock aquifer.
During the RI, five monitoring wells (MW-14, MW-15, MW-18, MW-20, and MW-21) were
examined for identification of geophysical fractures and indications of hydrologic activity.
Hydrologically active fractures are those that appear to be contributing water to the water column
under static well conditions, and these hydrologically active fractures may potentially act as
contaminant transport pathways. Locations of fractures, strike and dip angles, and potential
hydro logic activity at these locations are outlined in the RI Report (US EPA 1997c). However, the
lateral and vertical extent of the hydrologically active, or potentially active, fractures were not
determined. Furthermore, the interconnectivity of the fractures was also not defined.
1.4.4 EXISTING GROUNDWATER MONITORING WELLS
Groundwater monitoring wells screened within the top of bedrock and bedrock aql!ifers are present
throughout various site areas. These wells are denoted as permanent groundwater monitoring wells
(prefixed by MW-) and previously owned residential wells that have since been converted to
groundwater monitoring wells (prefixed by CW-). Currently, there are 11 permanent and 2
converted residential groundwater monitoring wells screened within the top of bedrock aquifer. In
contrast, there are IO permanent and 7 converted residential groundwater monitoring wells screened
within bedrock aquifer. No groundwater monitoring wells exist within the saprolite aquifer. The
98-03 sn1.i0-0161os24 1-22
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screened interval depth, screen length, well diameter, and additional specifications for these wells
are summarized in Table 1-2. Well specification data gaps are identified in Table 1-2 and may be
filled during additional data review activities.
Well specifications indicate that many of the existing groundwater monitoring wells may not be
appropriate for evaluation of in situ and enhanced in situ bioremediation processes. Two reasons
exist for this. First, many of the screened intervals or open borehole intervals (bedrock wells only)
of the groundwater monitoring wells are variable. Although the screened intervals are highly
dependent upon the depth of bedrock at each location, a "hydraulic connection" between
groundwater monitoring wells must be verified to ensure that sampled wells lie along a contaminant
flow path. Second, the screened interval lengths for the bedrock monitoring are also variable and
· generally greater than IO feet long. Well screen lengths greater than 10 feet result in substantial
concentration averaging of contaminants and geochemical parameters, thereby complicating data
evaluation. Furthermore, the variability in well screen lengths complicates data evaluation,
regardless of whether wells are hydraulically connected. Thus, many of the existing groundwater
monitoring wells are not adequate for sampling groundwater parameters necessary for performing
a quantitative bioremediation evaluation.
1.4.5 EXTENT OF CHLORINATED ALIPHATIC HYDROCARBON
CONTAMINATION
Analytical results from groundwater, soil, and sediment samples collected between 1991 and 1996
at the Site are described in the RI Report (US EPA 1997c). The following summarizes our current
understanding of the nature and extent of CAH contamination at the Site.
1.4.5.1 CAH Soil Contamination
Neither Source Area A nor Source Area B contain residual CAH contamination. It is believed that
the contaminants migrated through the soil directly into the shallow aquifer. CAHs in surface soil
likely evaporated.
9S-OJSn740-076/0824 1-23
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Table 1-2
Monitoring Wells Specifications
North Belmont PCE Site North Belmont NC
Screened Interval Screened Length Well Diameter Total Depth
Aquifer Location Sample (ft bgs) (fl) (Inches) (ft bgs)
Top of Bedrock MW2 X NA NA NA 89
MW4 X NA NA NA 82
MW5 X NA NA NA 113
MW6 X 117-127 10 2 127
MW7 X 106--116 10 2 118
MW8 X 34--44 10 2 45
MW9 X 64-74 10 2 74.5
MWIO X 57-,,7 10 2 67
MWII 63-73 10 2 73
MWl2 X 59-,,9 10 2 69
MW13 X 31-41 10 2 41
CWI X NA NA NA 105
CW8 X NA NA NA 71.7
New Well* X To Be De1ermme
Screened/Open Length of Depth to Bottom
Borehole Interval Open Borehole Well Diameter of Casing Depth to Bedrock Total Depth
Aquifer Location Sample (ft bgs) (fl) (Inches) (ft bgs) (I\ bgs) (fl bgs)
' Bedrock MW3 X NA NA NA NA 89 150 N _,. MWl4 X 128-145.8 18 4 128 128 145.8
MWl5 118-140 22 4 118 118 140
MWl6 X 69-72.5 4 4 69 69 72.5
MWl7 X 28.4--50 22 4 28.4 28.4 50
MWl8 139-161 22 6 139 139 161
MWl9 77-179.7 103 6 77 77 179.7
MW20 105.5-122.5 17 6 105.5 105.5 122.5
MW21 X 46--83 37 6 46 46 82.96
MW22 75-102.6 28 6 75 75 102.6
CW2 NA NA NA NA 120 177.6
CW3 X NA NA NA NA 120 184
CW4 NA NA NA NA 120 148
CW5 NA NA NA NA 40 53.4
CW6 X NA NA NA NA 64 84.4
CW7 X NA NA NA NA 60 105.2
CW9 NA NA NA NA 65 130.4
21 X NA NA NA NA NA NA
99 X NA NA NA NA NA NA
3.01 X NA NA NA NA NA NA
MW= Permanent monitoring well
CW= Converted municipal well
NA= Data currently not available; additional data review may fill these data gaps
* Location of new well will be determined.
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1.4.5.2 CAH Surface Water and Sediment Contamination
Surface water and sediments sampled at the Site were not affected by the volatile CAH
contaminants.
1.4.5.3 CAH Groundwater Contamination
The extent of CAH contamination has been segregated into Source Area A and Source Area B
contamination for each of the three aquifers. Conclusions drawn from the RI Report (USEPA
1997c) suggest that the contaminant plumes are spreading, and therefore the actual extent of
contamination may differ substantially from the following preliminary descriptions.
Source Area A
Saprolite Aquifer: Groundwater sampling at.shallow temporary monitoring wells (STW) located
south of the Roper's shopping Center in June 1996 indicated PCE concentrations as high as
2,200 µg/L (STW-6). The distribution of PCE and two of its biodegradation products, TCE and cis-
1,2-DCE, at locations sampled within the saprolite aquifer are presented in Figures 1-9 through
1-11. Although the former Untz dry cleaning facility appears to be positioned within the top of a
localized groundwater mound (Figure 1-7), potentiometric contours suggest the tendency of
groundwater to flow in a general north to northeast direction from suspected source areas. Thus, the
primarily contaminated regions are believed to coincide with the direction of groundwater flow and
lie north to northeast of the former Untz family dry cleaning facility. Full delineation of the
contaminant plumes along the perimeter and downgradient regions has not be accomplished.
Top of Bedrock Aquifer: Groundwater samples collected at temporary and permanent monitoring
wells indicate an extensive PCE groundwater plume that extends across the majority of the Site
(~igure 1-12). In addition, extensive TCE and cis-1,2-DCE groundwater plumes exist and are
primarily contained within the PCE plume (Figures 1-13 and 1-14). The highest recorded
concentration of PCE was at monitoring well MW6 in October 1996 (2,500 µg/L) and was
coincident with elevated biodegradation daughter product concentrations (TCE = 49 µg/L; cis-1,2-
DCE = 76 µg/L). Although groundwater flow directions within the top of bedrock aquifer have not
98-035/77-t0.076/0824 1-25
I!!!!!!! l!!!!!!!I l!!!!!I ==
561500
561000
1il ,fQ
(')-z 560500 ~ [l'.
0 z
560000
559500
55900
'1386500 1387000 1387500
== l:iiiiiil
1388000 1388500 1389000
EASTING, feet
liiiii liiiil
1389500
liiiil
I 1390000
iiiil iiiil
. ,
/!
// , ,
! I. : I
/,!
·······-·1·
1390500
FIGURE 1-9 SHALLOW GROUNDWATER PLUME, PCE CONTAMINATIOI~. JUNE 1996
REMEDIAL INVESTIGATION REPOtH
NORTH BELMONT PCE SUPERFUND SITE
N_(JRTH BELMONT, GASTON COUNTY, NC
-
...... 5
NOT TO SCALE
!!!!I
0 c.
;n
'ii • o, r, D ;n
l!!!!I l!!!!!!I
56200Cl
56"1!500
I 56"IOOOl
' 560500!
i :
i I
I 560000~
55950G·
i
I 559000;
~EIPA
··r
1386500
== ==
·--[__
-·-, .. --·---· -·----· ·r
1387000 1387500
== i=;::i liiiiiia
- ----_J___ ---
I 1388000
------·---··'--------
/i
i:
!
···---(""
1388500
liiiiiiil
·-·-..:,.-,:
Ii ,.
·······----j
1389000
EASTING, feet
liiiiiiil liiii iiii
__ l__ ___ . _____ ]
----·-··1 ... -----·-· .. ("'""
1389500 1390000
iiii liiiil
i 1390500
FIGURE 1-10 SHALLOW GROUNDWATER PLUME, TCE CONTAMINATION, JUNE 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUND SITE
NORTH BELMONT, GASTON COUNTY, NC
iiiil iiiil iiil
/ '
.·..:
NOTTO SCALE
l!!!!!!!!!I l!!!!!!!!!I l!!!!!I I!!!! == == ;;;;:;; liiiiiiil liiiiiiiiil liiii liiiii liiiil liiiil iiiii iiil -
562000
561500
561000
·a;
,IE
(') z 560500-~ 0 z
560000
559500
559000 ~---,1 ------,,-----,,-----,------..-----~-----~----~------,----_J
1386500 1387000 . 1387500 1388000 1388500 1389000 1389500 1390000 1390500
··70
EASTING, feet
FIGURE 1-11 SHALLOW GROUNDWATER PLUME, DCE CONTAMINATION, JUNE 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPER FUND SITE
NORTH BELMONT, GASTON COUNTY. NC
NOT TO SCALE
-l!!!!!!!!!I !!!!I !!!!I
561000
1i,
J!1
l'.i z ~ 560500-
z
l!!!!!!'J == r::::;:;a liiiiil liiiiil liiiiil liiii iiiii
FIGURE 1-12 TOP OF BEDROCK GROUNDWATER PLUME (TEMPORARY WELLS and PERMANENT WELLS)
PCE CONTAMINATION, OCTOBER/NOVEMBER 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUND SITE
NORTH BELMONT. GASTON COUNTY. NC
iiiii liiil -
ug/L
500
• I
. ,15
NOTTO SCALE
-
0 C, ,,
I!
0 n 0
-1111 1111
561000-
1il J!!
c§ z ~ 560500
z
1386500
l!!!!!I I!!!!!
138 000 138 500
1!1111 == ;;;a ;;;;;;a iiiii iiiiii iiiiii iiiii iiiiil -
ug/L
ltoo
1388000 1388500 1389000 1389500 1390000 1390500
EASTING, feet
"''=====================":""==============-========================-dJ.l
FIGURE 1-13 TOP OF BEDROCK GROUNDWATER PLUME (TEMPORARY WELLS and PERMANENT WELLS)
TCE CONTAMINATION, OCTOBER/NOVEMBER 1996 NOTTO SCALE
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPER FUND SITE
NORTH BELMONT. GASTON COIJNTY NC
1!!!!111!1 l!!!!!!!I l!!!!!!I
562000·
561500-
561000
1i5 ~
C'.) z ~ 560500-
z
560000
559500·
1386500
0 □
!!!!!I
1387000
I!!!!!! !!::I
I 1387500
== liiiiiiiiil liiiiiiiiil iiiiiil liiii liiii iiii iiii iiiil
,70
35
1388000 1388500 1389000 1389500 1390000 139b5oo 1391000
· EASTING, feet
"''===========-=~=~=-=====c==cc=======~==~=======================d
FIGURE 1-14 TOP OF BEDROCK GROUNDWATER PLUME (TEMPORARY WELLS and PERMANENT WELLS)
CIS-1,2 DCE CONTAMINATION; OCTOBER/NOVEMBER 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPERFUND SITE
NORTH RFI MONT Q.ASTON r.OI INTY Nf':
NOTTO SCALE
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been defined, the distribution of contaminant plumes suggest that groundwater flows in a general
north to northeast direction from the former Untz family dry cleaning facility.
Bedrock Aquifer: Groundwater samples collected at permanent, converted residential, and
residential groundwater wells indicate an extensive PCE groundwater plume that extends in a
northeasterly direction from the former Untz family dry cleaning facility (Figure 1-15). In addition,
extensive TCE and cis-1,2-DCE groundwater plumes exist and are primarily contained within the
PCE plume (Figures 1-16 and 1-17). The highest recorded concentration of PCE was at monitoring
well CW6 in October/November 1996 (3,500 µg/L) and was coincident with elevated biodegradation
daughter product concentrations (TCE = 280 µg/L; cis-1,2-DCE = 940 µg/L). Groundwater flow
in the bedrock aquifer flows in a general north to northeast direction from the former Roper's
Shopping Center dry cleaning facility (Figure 1-8) and is consistent with the spatial migration of
the groundwater contaminant plumes.
Source Area B
Saprolite Aquifer: Groundwater samples have never been collected in the saprolite aquifer for
Source Area B. Thus, the extent of groundwater contamination in the saprolite aquifer is currently
unknown. However, the location of t.he former dry cleaning facility and Source Area B, in
conjunction with a northerly groundwater flow direction (Figure 1-7), justifies a contaminant
investigation north of the existing MW l O location.
Top of Bedrock Aquifer: Groundwater samples collected at permanent and temporary groundwater
wells indicate limited PCE contamination in the vicinity of Source Area B. Groundwater samples
collected at monitoring well MW IO in October 1996 indicate moderate concentrations of PCE
(80 µg/L); however, it is unclear at this time whether contamination at this monitoring well
originated from Source Area A or B. Groundwater flow directions within the top of bedrock aquifer
have not been defined, thereby making it difficult to speculate on the likely source of PCE
contamination at monitoring well MW! 0.
Bedrock Aquifer: Groundwater samples collected at permanent, converted residential, and
residential groundwater wells downgradient of the Source Area B location indicate non-detect
9g.035n1.io-0161os24 l-32
--- -
l!!!!!!!!I !!!!!!!!!I
562000
561500
561000
1i3 ~
~ ~ 560500 O'. 0 z
560000
559500
1387000 1387500
~EPA
== iiii iiii -- ------
uglL
I.
i :
I
1·.· .• '5
1388000 1388500 1389000 I 1389500 I 1390000 139b500 I 1391000
EASTING, feet
FIGURE 1-15 BEDROCK GROUNDWATER PLUME (BEDROCK MW and POTABLE WELLS) NOT TO SCALE PCE CONTAMINATION, OCTOBER/NOVEMBER 1996 REMEDIAL INVESTIGATION REPORT .
NORTH BELMONT PCE SUPER FUND SITE
NORTH BELMONT, GASTON COUNTY. NC
- - --
.. \..
562000
\.
561500
561000
560500
560000
559500
......... T ...
I 386500
-l!!!!!!I
.. ... .. . .. .. . .. . .1. .....
1387000
··1
1387500
!!!!!!ill
..I
.. T ....... .
1388000
== l:liiiiiiil
I 1388500
iiii -
I ...... ··----------i·-··-··
1 389000 1389500
EASTING, feet
-
' 1390000
---- -
ugll
;:r:•~<,o . i
J
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J
• 5
···,····················T
1390500 1391000
FIGURE 1-16 BEDROCK GROUNDWATER PLUME (BEDROCK MW an<\ POTABLE WELLS)
TCE CONTAMINATION, OCTOBER/NOVEMBER 1996
NOTTO SCALE
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPER FUND SITE
NnRTl---1 RFI MnNT nA~T()N r:n1 INTV hlr.
-- - --
562000
561500
561000
1il .g,
('j z
~ 560500
z
560000
559500
1386500 1387000
---l!!!!!!I liiii iiiil -- - - --' ----------...-------------
1387500 1388000 1388500 1389000
EASTING, feet
I 1389500 1390000
FIGURE 1-17 BEDROCK GROUNDWATER PLUME (BEDROCK MW and POTABLE WELLS)
CIS-1,2 DCE CONTAMINATION, OCTOBER/NOVEMBER 1996
REMEDIAL INVESTIGATION REPORT
NORTH BELMONT PCE SUPER FUND SITE
NORTH BELMONT, GASTON COUNTY, NC
I 1390500
... T
1391000
1()(,0
'7t)
NOT TO SCJ1LE
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concentrations of CAH contaminants. These findings suggest that contaminants have not yet
migrated into the bedrock aquifer at this location.
1.4.6 EVIDENCE OF BIOLOGICAL PROCESSES
Evidence of active biological processes at the site exists. This evidence is suggested by the presence
of TCE and cis-1,2-DCE, which are both reductive dechlorination daughter products of the source
contaminant, PCE. Since RI investigations did not report concentrations of VC, ethene, and ethane
(USEPA 1997c), it is unclear whether a complete reductive dechlorination pathway, leading to the
formation of innocuous ethene and ethane, exists at the site. Furthermore, speculation regarding the
oxidation of cis-1,2-DCE and VC (if present) cannot be made with the limited data set.
During December 1997, groundwater samples were collected at several monitoring wells across the
site and analyzed for various electron acceptor/metabolic byproduct and nutrient concentrations.
Results from analyses were submitted to USEPA (KABIS Sampler Evaluation and Natural
Attenuation Parameters Evaluation, North Belmont PCE Site, SESD Project No. 98-104) and are
summarized in Table 1-3. Since dissolved oxygen and VOC concentrations were not collected at
sampled locations, a detailed analysis of the data is not justified. However, the data indicate low
availability of analyzed electron acceptors/metabolic byproducts (nitrate/nitrite, sulfate, sulfides, and
methane) and nutrients (ammonia, total Kjeldahl nitrogen, and total phosphorous). In addition,
ethene and ethane concentrations were low, with estimated values below 1.0 µg/L. This fact in
conjunction with reductive dechlorination daughter products at these locations during the RI
suggests that a complete and/or significant reductive dechlorination pathway of PCE to ethene and
ethane may not exist at these locations or that ethene and ethane are readily biodegraded. In
summary, the low availability of electron acceptors/metabolic byproducts suggest that enhancement
of intrinsic biodegradation processes may be a feasible remedial technology at the Site.
1.4.7 DATA NEEDS
The following data needs are based on the current understanding of the Site and fulfillment of these
needs is essential to the future evaluation of enhanced in situ bioremediation technologies. Data
needs identified below will be fulfilled during future field tasks using the phased approach
98-03 5/77 40--076/0824 1-36 J
- - - - -
DO
Location Date (mg/L)
MWIIK Dec-97 NA
MWl4K Dec-97 NA
MW14KA Dcc-97 NA
MIVl4P Dec-97 NA
CW6K Dec-97 NA
CIV6P Dcc-97 NA
DO= Dissolved oxygen
A = A vcrage val uc
J = Estimated value
NA= Not analyzed
- -
l!!!!!!!!!!I I!!!!!! liiii iiiii - - -
Table 1-3
Screening Results for Electron Acceptors/Metabolic Byproducts and Nutrients
North Belmont PCE Site North Belmont. NC
(Nitrate/Nitrite)
-Nitrogen Sulfate Sulfides Methane Ethcne Ethane
(mg/L) (mg/L) (mg/I,) (µg/1,) (µg/L) (µg/L)
1.8 1.3 0.20U 5.9U 12U 12U
0.19 2.0 0.04U 5.9U 0.36) 0.30)
NA NA NA 5.9U 0.27) 0.25)
0.84A 1.5 0.04U 0.67) 0.16) 0.29)
3.5 0.42 0.04U 5.9U 12U 12U
2.9 OAIA 0.04U 5.9U 12U 12U
Total Kjeldahl
Ammonia Nitrogen
(mg/L) (mg/I,)
0.05U 0.IU
0.22 0.32
NA NA
0.I0A 0.18A
0.05U 0.24
0.05U 0.11
U: Material was analyzed for but non detected. The numeric value is the quantitation limit.
' w __,
---
Total
Phosphorous
(mg/L)
1.3
0.05
NA
0.02A
0.16
0.08
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introduced in Section 2. Results from the field characterization will fill data gaps and be used to
refine the site conceptual model.
General
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Further characterization of the site geology. Activities should be focused on identification of
fault zones, stress relief fractures, and mineralogic zones that may serve as preferential flow
paths for the migration of site contaminants.
Further characterization of the site hydrology within the three aquifer zones. This will involve
determination/verification of hydrogeologic parameters which include: groundwater flow
directions, seepage velocities, hydraulic conductivities, hydraulic gradients, effective porosities,
contaminant retardation coefficients, and the effects of recharge.
Evaluate the utility and hvdraulic connection of existing and newly installed groundwater
monitoring wells. At minimum, this will involve filling data gaps listed in Table 1-2 and
consideration of hydrogeologic parameters. If these data cannot be obtained then existing
monitoring wells may be inappropriate for future data collection needs. Dye tracer studies may
be necessary for determining the hydraulic connection between wells.
Determination of parameters affecting biological attenuation of site contaminants. This will
involve determination of various electron acceptor/donor concentrations, groundwater redox
conditions, and the abilities of the microbial consortia present to biodegrade site contaminants.
Identify potential receptor exposure pathways. This is necessary to determine whether the
chosen remedial technology is protective of human health and the environment.
Saprolite Aquifer
• Characterization of Source Area A and Source Area B contaminant distribution. Although
previous site characterization activities were performed at the Source Area A location, the
perimeter of the contaminant plume was not delineated. Characterization activities should
focus on the source area and downgradient extent of contamination, which is currently believed
to extend in a no:1heasterly direction from the former Untz family dry cleaning facility. No
previous investigations at the Source Area B location have been performed.
Top of Bedrock Aquifer
• Further characterization of the groundwater contaminant plume in the Source Area B location .
Only limited groundwater monitoring wells exist in this area.
98-035/7740-076/0824 1-38
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Bedrock Aquifer
Determine the ability to pump within this aquifer. Remedial alternatives will likely require the
ability to pump groundwater from or into this aquifer or the determination that such activities
are technically infeasible.
98-0JSn740-076/0824 1-39
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2.0 UNDERSTANDING ENHANCED IN SITU BIOREMEDIATION
2.1 HISTORY OF IN SITU BIOREMEDIATION
Until recently, groundwater contaminated with CAHs, such as PCE, was only remediated through
physical techniques such as soil vapor extraction, pump and treat, or variations of these technologies
including in situ air-stripping. However, these physical techniques move the contaminants from one
medium to another (e.g., air or sorbed to carbon). In most cases, the contaminants must be further
thermally treated to destroy them. In addition, most of these technologies are limited in the removal
rate or their efficiency by the desorption rate from soils in the saturated zone. Therefore, most
extraction systems have failed after shutting down the system and seemingly remediating the
groundwaters.
Biodegradation of CAHs has only recently been demonstrated to be feasible in the environment
when mediated by natural microbial systems. CAHs are now known to be biodegradable aerobically
and anaerobically, although the latter mechanism is the most effective intrinsic mechanism found
in most natural systems. COM has successfully implemented both aerobic and anaerobic
bioremediation systems for treatment of CAHs.
2.2 DESCRIPTION OF TECHNOLOGY
Enhanced in situ bioremediation technologies are effective means of enhancing the rate and extent
of naturally occurring biodegradation processes. These technologies are typically very effective
at remediating CAH compounds found at the Site. However, to evaluate the potential effectiveness
of enhanced in situ bioremediation technologies, field and laboratory investigations must first be
conducted to determine if such technologies are technically_ and economically feasible. These
investigations will identify field conditions compatible to anaerobic or aerobic biodegradation,
identify potential pilot study areas, and develop laboratory data to support a field remedial pilot
design. Once these initial investigations are complete, strategies can be developed to enhance and
monitor those factors influencing intrinsic biodegradation processes, if necessary. For example, if
insufficient electron donor or nutrient is present to "drive" the anaerobic reactions needed for
remediation of CAHs, then addition of these constituents to the aquifer may be investigated.
98-035177-UJ-076/0824 2-l
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Alternatively, enhanced bioremediation techniques may focus on aerobic strategies using specific
microbes known to degrade the CAHs found at the Site.
Enhan.ced in situ bioremediation may involve the stimulation or enhancement of either anaerobic
or aerobic biodegradation processes. A brief discussion regarding the enhancement of both
anaerobic and aerobic processes is provided below.
Anaerobic Processes
Enhanced anaerobic biodegradation (EAB) relies on the addition of sufficient organic compounds
to contaminated groundwater to induce highly reducing methanogenic conditions necessary to
achieve reductive dechlorination of chlorinated solvents. By inducing highly reducing methanogenic
conditions, EAB may improve both the extent and rate of dechlorination reactions. Inherent in the
technically and economically feasible implementation of EAB is that site groundwaters have only
low levels of alternative electron acceptors, such that only a minimal addition of organic compound
is necessary to achieve and sustain a highly reduced groundwater environment. The current redox
environment and hydraulic transport conditions are unknown at the Site, and include:
biodegradation rates, electron acceptor concentrations, and available organic carbon content. The
feasibility of this remedial alternative is currently unknown and will rely largely on results from
electron acceptor analyses of the site groundwaters, results from microcosm studies, and a field pilot
study.
Enhanced anaerobic biodegradation is an innovative technology that has been implemented at
relatively few sites. Approximately 6-8 pilot demonstrations have been performed in the past two
years indicating this technology is still in the developmental stage. However, USEPA and the USAF
have developed draft guidelines for a technical protocol for determining its feasibility and
implementation.
Aerobic Processes
Enhanced aerobic biodegradation relies on the stimulation or enhancement of aerobic biodegradation
processes. This may include the addition of electron acceptor (i.e., dissolved oxygen), inorganic
98.035n740-076/0824 2-2
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nutrients (e.g., ammonia, phosphate), and microorganisms, or by stimulating the fortuitous
enzymatic attack of target compounds by addition of substrates (e.g., phenol, toluene). This
technology is highly dependent on the chemical characteristics of the aquifer, which includes both
organic and inorganic contaminants/constituents. The feasibility of this remedial alternative is
currently unknown and would rely largely on results from electron acceptor analyses of the site
groundwaters, results from microcosm studies, and a field pilot study. Although this technology is
compatible with in-well vapor stripping, implementation of enhanced aerobic biodegradation is site
dependent and generally much more difficult to maintain than EAB.
For CAH compounds found at the Site, enhancement of anaerobic processes will likely be the most
preferred and effective technology -from both a technical and economic standpoint. Thus, the focus
of this Treatability Work Plan will be on the enhancement of anaerobic processes. Should
enhancement of anaerobic processes not be an adequate technology, then enhancement of aerobic
processes will be considered at a later date.
2.3 APPROACH TO EVALUATING ENHANCED ANAEROBIC BIODEGRADA TION
Preliminary evaluation of EAB requires the quantification of groundwater flow, solute transport, and
transformation processes, including rates of intrinsic biodegradation. Quantification of these items
are nec~ssary to determine: (I) contaminant fate and transport and mechanisms within all aquifer
zones, (2) the extent and locations in which intrinsic biological attenuation of contaminants are
occurring and are feasible, (3) whether aerobic or anaerobic processes are best suited for enhancing
the ultimate attenuation of contaminants, and (4) the factors affecting and limiting naturally
occurring (i.e., intrinsic) biodegradation processes. Evaluation of these items are used to develop
a detailed site conceptual model and strategies for potentially enhancing and monitoring those
factors influencing intrinsic biodegradation processes. Although a preliminary site conceptual
model is presented in Section 1.3, identified data needs preclude the quantification of the above four
factors. Successful implementation of the enhanced in situ bioremediation option will require
completion of the following steps:
Fulfillment of identified data needs using a phased approach.
98--03S/7740.076/0824 2-3
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Refine the conceptual model based on the newly acquired site characterization data.
Document indicators of intrinsic biodegradation processes and the potential for
enhancement.
lfappropriate, simulate biological processes using analytical or numerical solute fate and
transport models that allow incorporation of a biodegradation term, as necessary.
Determine the potential benefits of enhancing biological processes with respect to
contaminant transport.
If the enhanced in situ bioremediation option is feasible, proceed with a laboratory
microcosm study to determine its applicability to the Site and to optimize electron
acceptor/donor and nutrient formulations.
If the microcosm study supports the feasibility of enhanced in situ bioremediation, proceed
with a field-scale test system.
Selection of locations (i.e., test plots) for the field-scale test system, for characterization
of contaminant, geochemical, and hydrogeologic parameters. These test plots are to cover
various redox zones within the contaminant plume and their locations should be selected
based on review of the site conceptual model. Test plot locations will be chosen to take
advantage of existing groundwater wells, thereby minimizing the need for installing new
groundwater monitoring wells.
Collect field characterization data at each location within the test plots. Installation of
groundwater monitoring wells will involve collection of aquifer core samples for further
characterization of the stratigraphy. Groundwater will be sampled at all test-plot
locations, and at various locations across the site. Groundwater samples will be analyzed
for contaminant concentrations and geochemical parameters including electron
acceptors/donors. A tracer study will be performed at all test-plot locations for evaluating
the hydraulic connection between sample locations.
Evaluate the performance of the field-scale test system using the optimum electron
acceptor/donor formulation identified from the microcosm study and a regular monitoring
program.
Proceed with a pilot-scale or full-scale implementation of enhanced in situ bioremediation,
if appropriate, or select an alternative remedial strategy based on the revised site
conceptual model and current understanding of the Site.
The primary focus of this Treatability Work Plan is to develop a phased strategy for evaluating the
potential for enhancing intrinsic biodegradation processes already occurring at the Site. This work
plan comprises five phases designed to screen the Site to determine that site-specific characteristics,
regulatory constraints, or other logistical problems suggest the technology is feasible to employ.
The phases include:
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•
•
2.4
Phase I-Field Characterization
Hydraulic parameters
Electron acceptors/donors
Geochemical parameters
Phase II-Data Evaluation and Technology Assessment
Identification of factors affecting in situ degradation
Biodegradation rate estimates
Contaminant transport model predictions
Receptor exposure analysis
Develop work plan for laboratory
Conduct field tracer study
Phase Ill-Laboratory Microcosm Studies
-Develop work plan for field-pilot study
Phase IV-Field-Scale Pilot Study
Phase Y--Conclusions and Recommendations for Remedial Design
OBJECTIVES
The objectives of this Treatability Work Plan are:
1. Develop a detailed conceptual understanding of the Site including additional data needs for
determining applicability of enhanced in situ bioremediation technologies.
)
2. Conduct focused field characterization based on data needs.
3. Identify indications of intrinsic bioremediation processes in the groundwater plumes at the Site.
4. Determine controlling factors affecting the biological attenuation of contaminants by
conducting microcosm tests.
5. Select location(s) for field test site and conduct tracer studies.
6. Determine feasibility of enhanced in situ bioremediation technologies.
7. Conduct field treatability and large pilot or full-scale evaluations.
8. Evaluate feasibility of full-scale system relative to competing technologies and make final
selection for appropriate remedial strategies.
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3.0 PHASE I-FIELD CHARACTERIZATION
3.1 OVERVIEW AND APPROACH
This section of the Treatability Work Plan contains the Sampling and Analysis Plan (SAP). The
sampling will consist of groundwater sampling and saturated zone soil sampling at select locations
throughout the Site. Specifications for the acquisition of soil and groundwater samples; methods
for the determination of field parameters; and laboratory analytical requirements to help document
in situ bioremediation processes are provided in this SAP. This sampling is performed to help fill
data needs identified in the preliminary site conceptual model regarding the extent and nature of
groundwater contamination and the hydrogeoiogic, physical, and chemical parameters affecting
biological processes in both soils and groundwater (Section 1.3 .6). Data collected under the
guidance of this SAP will be used to determine the feasibility of using enhance in situ
bioremediation technologies at the Site.
Field characterization activities to be performed in guidance with this SAP are separated into four
Tasks. Task I involves mobilization and final data review. Task 2 specifies site screening activities
for characterizing the saprolite aquifer and selection of future well installation locations. Task 3
specifies sampling acquisition and handling procedures for groundwater and soil sample collection.
Samples collected during Task 3 activities include existing groundwater monitoring wells and
temporary sample locations installed during Task 2 activities. Finally, Task 4 specifies well
installation activities based on Task 2 and 3 results.
3.2 SAMPLING AND ANALYSIS PLAN
3.2.1 SELECTION OF GROUNDWATER MONITORING WELLS
Based on review of the preliminary site conceptual model (Section 1.3), existing monitoring well
and residential well locations have been selected for future groundwater sampling and analysis.
These locations are summarized in Table 3-1. Well specifications, which include total depth and
screened interval zones, are presented in Table 1-2. Additional groundwater samples will be
collected at temporary sample locations installed during Task 2 activities.
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Table 3-1
Existing Groundwater Monitoring Wells and Residential Wells
Selected For Sampling
Aquifer Monitoring We/1 /dentijication Assumed Source Area
Top of Bedrock Aquifer
MW2 A
MW4 A
MW5 A
MW6 A
MW? B
MW8 A
MW9 B
MWIO B
MWl2 A
MWl3 A
CWI A
CW8 A
Bedrock MW3 A
MWl4 A
MWl5 B
MWl6 A
MWl7 A
MWl8 B
MW21 A
CW3 A
CW6 A
CW? A
21 A
99 A
3.01 A
3.2.2 ANALYTE SELECTION
Selected organic and inorganic analyses to be performed on groundwater and soil samples collected
during field characterization activities are summarized in Table 3-2. These parameters assist in
determining the extent of in situ biological degradation which may be occurring at the Site; the
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conditions under which degradation is occurring; and the distribution of selected Site contaminants.
Justification for required analyses listed in Table 3-2 is provided below.
Table 3-2
Sampling Requirements and Analytical Methods
Sample Matrix Field
Analytical Filtered
Water Soil Analyte Instrument Method Bottle Req. (YIN) Preservative
Field Parameters
X Dissolved Orion 820 NIA NIA NIA NIA
Oxygen
X Eh Orion 230A NIA NIA NIA NIA
X Dissolved YSI flo,"'·-thru meter NIA NIA NIA NIA
Oxygen
X pH YSI tlow-thru meter NIA NIA NIA NIA
X Specific YSI flow-thru meter NIA NIA NIA NIA
Conductivity
X Temperature YSI flo,.,·-thru meter NIA NIA NIA NIA
Ionic Parameters (Onsite Analyses)
X Sulfate Spec DR2000 HACH 8051 250 ml plastic N Cool 4•C
X Iron (II) Spec DR2000 HACH 8146 250 ml plastic y Cool 4"C
X Alkalinity Spec DR2000 HACH 250 ml plastic N Cool 4•C
X Chloride Spec DR 2000 HACH 8113 250 ml plastic N Cool 4•C
X Hydrogen Sulfide Field HACH Field N Cool 4•C
X Carbon Dioxide Field HACH Field N Cool 4•C
X Ammonia Spec DR2000 HACH 250 ml plastic N Cool 4•C
X Phosphate Spec DR2000 HACH 250 ml plastic N Cool 4•C
Ionic Parameters/Gases (Laboratory)
X Nitrate/Nitrite -USEPA 300.0 1-L N -
Polyethylene
X Methane/Ethane/ -RSKSOP-175 3-40 ml VOA N H,so,
Ethene vials Cool, 4"C
X Dissolved -Bubble Strip" Custom N Cool, 4•C
Hydrogen Gas
Organic/Inorganic Parameters (laboratory)
X DOC -USEPA 9060 125 ml amber N H2SO4
glass Cool. 4"C
X TOC -USEPA 9060 I 00 g glass jar N Cool, 4"C
Modified
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Table 3-2 (continued)
Sample Matrix
Water Soil Analyte Instrument
X Volatile Organics -
X Volatile -
Organics••
X Soil Grain Size -
X Soil Bulk -
Densitv
NI A -Not applicable
~ Bubble strip-Microseeps Analytical Laboratory.
·• Collection detennined based on field decisions (Section 3.6.2)
TOC = Total Organic Carbon
DOC= Dissolved Organic Carbon
Analyses of Groundwater Samples
Analytical
Method
USEPA 8260
ASTM
C357-85
ASTM
D421-85
Field
Filtered
Bottle Req. (Y/N) Preservative
3-40 ml VOA N HCI
vials
N Cool, 4"C
N None
N None
General Groundwater Parameters: General groundwater parameters such as pH, temperature,
dissolved oxygen, redox potential (Eh), specific conductivity, alkalinity, and chloride concentrations
will be determined by analyte specific probes (pH, temperature, dissolved oxygen, redox potential,
and specific conductivity) or by field test kits (alkalinity and chloride). The general groundwater
parameters help define groundwater flow paths. In addition, the parameters are used to evaluate if
the environment is favorable for microbial growth. All groundwater samples should be analyzed
for these parameters.
Electron Acceptors and Metabolic Byproducts: The concentrations of electron acceptors (oxygen,
nitrate/nitrite, sulfate, carbon dioxide) and metabolic byproducts (iron II, hydrogen sulfide, methane,
and carbon dioxide) in the subsurface will be determined by external laboratory analysis
(nitrate/nitrite and methane) or by field testing (oxygen, iron II, sulfate, hydrogen sulfide, and carbon
dioxide). Concentration contour maps of each electron acceptor or metabolic byproduct can be used
to refine the conceptual model by evaluating the dominant biological processes throughout the Site.
All groundwater samples should be analyzed for these parameters.
Macronutrients: Ammonia and or/ho-phosphate are essential macronutrients for biodegradation
processes. These analytes should be analyzed to indicate whether amendment of these nutrients is
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likely to enhance biodegradation processes. All groundwater samples should be analyzed for this
parameter.
Volatile Organic Compounds: These analyses are used to determine the type, concentration, and
distribution of volatile organics in each aquifer. These analyses are essential as they will indicate
the concentration and distribution of contaminants of concern (i.e., chlorinated solvents) throughout
the Site. All groundwater samples should be analyzed for this parameter.
Dissolved Organic Carbon: Dissolved organic carbon (DOC) will be analyzed to determine
concentration and impact on biodegradation. DOC is a critically needed component in chlorinated
solvent contamination and a potential drain on electron acceptors at petroleum sites. Any
anaerobically biodegradable organic compound can serve as an electron donor for chlorinated
solvent dechlorination. DOC is the best available measurement to determine the available electron
donor concentrations. Sufficient electron donor must be available to maintain anaerobic redox
potential for complete dechlorination. All groundwater samples should be analyzed for this
parameter.
Molecular Hydrogen: Dissolved molecular hydrogen (hydrogen gas) can serve readily as an electron
donor during the reductive dechlorination of chlorinated solvents. Furthermore, dissolved molecular
hydrogen can be used as an indicator of the redox potential of groundwater. Until recently, this
analysis was prohibitively expensive, but recent advances have made this important parameter
economicaily feasible. All groundwater samples should be analyzed for this parameter.
Analyses of Soil Samples
Volatile Organic Compounds: These analyses are used to determine the type, concentration, and
distribution of volatile organics associated with site soils. This measurement will help determine
the source of soluble VOCs. One sample will be collected from each monitoring well installed.
Total Organic Carbon: Determination of the Total Organic Carbon (TOC) in soil samples is critical
in evaluating the retardation of contaminants in the subsurface. In addition, soil TOC levels help
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provide a qualitative estimate for the expected persistence of DOC in site groundwaters. One sample
will be collected from each monitoring well installed.
Grain Size: Grain size analyses will be performed on select samples to provide data on lithological
characteristics and hydraulic conductivity estimates. These analyses will be conducted for two
locations within the saprolite aquifer.
Soil Bulk Density: These analyses will be determined for use in retardation coefficient estimates
and for evaluation of soil porosity values. These analyses will be conducted for two locations within
the saprolite aquifer.
3.2.3 DATA QUALITY OBJECTIVES
Data quality objectives (DQOs) are qualitative and quantitative statements which specify the quality
of the data required to support USEPA decisions during remedial response activities. DQOs for the
North Belmont PCE Site are located in the Field Operations Plan for the Site (COM Federal 1998).
3.2.4 MONITORING WELL INSTALLATION
Six to twelve permanent monitoring wells will be installed to monitor water bearing zones at the
Site. A discussion on monitoring well locations and rationale for these wells is in Sections 3.4 and
3.6. Thirty to forty temporary wells will be installed using direct-push technologies (DPT) to further
characterize the saprolite aquifer. A more detailed discussion is provided in Section 3.4.1.
Permanent Monitoring Well Construction
Soil samples will be collected from each monitoring well installed as discussed in Section 3.2.2. A
continuous two-inch diameter soil core will be collected from the top of bedrock aquifer for use in
a microcosm study. The soil core will be shipped in ice (4' Centigrade) in a sealed container to
maintain anaerobic conditions. if they exist.
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Each monitor well will be constructed of Type 316 stainless steel. Screens will be continuous wrap,
IO feet in length, and have a slot size of0.01-inch. The filter pack will extend at least 2 feet above
the top of the screen. The annular space above the sand pack will be grouted using Vole lay (30%
solids) pure bentonite grout with a minimum density of 10.2 pounds per gallon (lbs/gal).
Each new permanent monitor well will be surveyed vertically and horizontally to determine their
precise location and elevation. In addition, one round of water level measurements will be collected
at each existing and new monitoring well. These water level measurements will be used to construct
groundwater contour maps indicating the principal directions of groundwater movement, and to
evaluate horizontal gradients within each of the water bearing zones.
Temporary Monitor Well Construction
Direct push sampling equipment will be driven to approximately IO feet below the groundwater
table in the saprolite aquifer (approximately 3~0 feet). Upon driving the sampler to the desired
depth, the 6-inch stainless steel screen will be exposed and groundwater sample collected. The
screen will be approximately ¾-inch in diameter. Tubing attached to the sampler and exposed at
ground surface will be left in place for collection of additional groundwater samples at a later time
if desired. This tubing will be removed upon demobilization activities and the hole grouted with
volclay (30% solids) pure bentonite grout.
3.2.5 WELL DEVELOPMENT
Prior to use, all groundwater wells will be developed to remove fines, cuttings, and drilling. fluids
from the well and adjacent formation. Wells will be developed in a manner consistent with local,
state, and federal requirements. This will likely entail extraction of a minimum of IO well casing
volumes and stabilization of groundwater pH, temperature, specific conductivity, dissolved oxygen,
and redox potential.
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3.2.6 FIELD INSTRUMENT CALIBRATION AND MAINTENANCE
Field instrumentation will be required to provide data concerning health and safety considerations
and as a method for field screening samples. Instructions for discussion of instrument calibration
and operation are contained in the Quality Assurance Project Plan (QAPjP) located in the Field
Operations Plan for this site (COM Federal 1998).
3.2.7 SAMPLING METHODS AND EQUIPMENT
Monitor Well Purging and Sampling
I. Detailed instructions of the sample collection procedure and sequence will be reviewed with
the field manager onsite prior to initiation of groundwater sampling. The samples will be
collected and handled in a manner consistent with the Environmental Investigations Standard
Operating Procedures and Quality Assurance Manual. USEPA, Region IV, SESD, Athens,
Georgia, May 1996.
2. Obtain the following measurements:
Total length of well, L, (in feet)
Length to the static water level in the well, Lw (in feet to the nearest 0.0 I foot)
Diameter of the well, d (in feet)
L, will be measured directly using a weighted line.
Lw will be measured directly using a water level indicator.
All measurements are to be recorded in feet and decimals. All measurements instruments
will be decontaminated per standard operating procedures.
3. Using the formula below, determine the volume of water in the well.
Volume; 0. 785 (d2) (L, -Lw); cubic feet
Cubic feet x 7.5; gallons
4. Each well will be developed until three volumes are evacuated or until it is pumped dry. A
peristaltic pump will be used on wells with a shallow water table (i.e., less than 10 feet deep).
This method will produce low volume pumping at a rate of 0.1 gallon per minute (gpm). A
submersible or bladder pump will be used on wells with a deeper water table (i.e., greater than
20 feet deep). Pumping rate for deeper wells will be approximately I gpm.
The pui:np will be placed near the top of the water column to minimize the possibility of short-
cir~uiting (pulling water from outside the well directly into the pump instead of evacuating the
stagnant water in the well) during purging. Each well will be purged until pH, temperature,
specific conductance, and turbidity stabilize. These parameters will be measured on a periodic
basis until stabilization is attained. Well purging is typically accomplished by the time five
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volumes are purged. All purge water will be handled as described in the Waste Management
Plan, Section 3.0 of this Field Operations Plan, for this field effort.
5. Determine the required duration of purging by dividing the purge volume by flow rate.
6. The measurements required prior, during, and after the purge process will be recorded on the
well purge record.
7. After the well has been purged, collect the sample from the top of the water column using low
volume pumping (i.e., less than 0.1 gpm). The sample containers will be filled directly from
the peristaltic pump and vacuum jug assembly except for volatiles, which will be filled from
the teflon tubing. The deep wells will be purged using a submersible pump and sampled using
a bailer.
8. Add chemical preservatives to the samples. Note that the VOA containers will be preserved
prior to sample collection. Check the pH of the metals and cyanide samples.
9. Document the process.
I 0. Measure and record in the logbook the pH, temperature, specific conductance, and turbidity of
the sample. These measurements may be taken from a sample collected in an additional
container. All instrument calibrations will also be recorded.
11. Complete documentation and custody sealing of the sample.
12. Place samples in a polyethylene bag.
13. Identify, package, and ice samples for shipment.
14. Maintain chain-of-custody.
15. Ship samples to analytical laboratories.
Solid Material Sampling
All well materials samples (sand, grout, bentonite) will be poured or scooped directly into sampling
containers. Sample management will include steps 11 through 15 above.
3.2.8 SAMPLE IDENTIFICATION
The following codes refer to groundwater and solid media sample collection locations:
Site code: NB -North Belmont Superfund Site
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Sample media code:
Well/Cluster Number:
Depth code:
Example:
MW -N. Belmont monitor well samples
PW -N. Belmont private well samples
RS -rinsate sample
SN sand sample
BN -bentonite sand
GR -grout sample
02 -Well/cluster identification
00 -Solid media
SH -shallow well
DP -deep well
00 -solid media
NB-MW-02-SH
NB -North Belmont Site
MW -North Belmont Site monitor well groundwater
sample
02 -Sample\well number
SH -Shallow well
Note: Trip blanks will accompany each cooler shipment of VOC samples.
3.2.9 FIELD QUALITY CONTROL PROCEDURES
The level of quality control (QC) is based on the type of investigation. the level of accuracy and
precision required, and the intended use of the data. The USEPA document Data Quality Objectives
Process for Superfund, Interim Final Guidance, Office of Solid Waste and Emergency Response
(OSWER) Publication 9355.9-01 (September 1993) will be used to enforce QC. A number of
procedures will be implemented to ensure that QC is exercised in the field. Periodic surveillances
will be conducted as outlined in the CDM Federal ARCS IV Quality Assurance Management Plan
(Revision I, June 15, 1992) to check field compliance with this document. Accurate documentation
in the field logbooks will serve as backup checks. Field blanks and duplicate samples will assist in
maintaining sample integrity. Chain-of-Custody and security (custody) seals will protect samples
from tampering. The ultimate responsibility for QC lies with the Field Manager, as he will be onsite
to ensure compliance with all procedures.
Field meters and air monitoring instruments for health and safety purposes are required to be
calibrated, and the calibration documented in field logbooks. Positive Response Verification Checks
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will be conducted on instruments every 20 samples or every 4 hours, whichever is more frequent.
Checks on conductivity and pH meters will consist of checking the instrument against an analyte
standard. Checks for the dissolved oxygen meter will be to confirm the saturated air value at
I 00 percent. Data packages for samples collected for VOCs, SVOCs, and metals analyses will be
analyzed with data being reported according to Definitive Data requirements.
3.2.10 SAMPLE CUSTODY
All sample shipping containers will be sealed with a custody seal. Chain-of-Custody records will
accompany the samples to the analytical laboratory.
The field samples will remain in the custody of the sampling team, in actual possession of or in the
view of the team member(s) until they have been placed in a secure area or relinquished to
subsequent personnel as recorded on the Chain-of-Custody.
3.2.11 SAMPLE PACKING AND SHIPPING
Samples will be packaged for shipment in accordance with the requirements of the Department of
Transportation (DOT). Samples will be shipped in insulated containers with either freezer forms
or ice. If ice is used, it will be double-bagged in Ieakproofplastic bags. Samples will also be packed
in plastic bags. Delivery of the samples to the analytical laboratory will be by overnight carrier and
the containers will be marked as environmental samples.
A custody seal will be affixed to the outside of each cooler. It will be placed over the cooler seam,
and signed and dated. Nylon-reinforced tape will be placed over the seal to reduce the potential for
tampering or accidental tearing. All shipping bills will be saved by the Field Manager and will
become part of the project documentation.
3.2.12 DATA VALIDATION
Sample validation includes precision and accuracy of analyses, and sample management and
tracking. Accuracy and precision requirements are listed in Section 2.13 of the QAPjP. Samples
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will be tracked from the time they are put into sample containers until validated laboratory data are
received and final storage and transfer. of the sample residuals is completed. This will be done
through the use of unique sample numbers, sample container labels, field sheets, chain-of-custody
forms, and sample seals.
Data generated are validated on the basis of accuracy, precision, and how the data compare with the
established limits of detection. Attention will be paid to possible outliers. Statistical tests will be
used to ensure that if data are rejected, it is done with a high level of confidence. Refer to
Section 2.10.3 of the QAPjP for additional details on data validation procedures.
3.2.13 DOCUMENTATION
3.2.13.1 Logbooks
The field logbook is a controlled evidentiary document and will be maintained accordingly.
Logbooks will be made available by the Field Operations Manager. Each logbook will be assigned
a document control number prior to use.
Field logbooks provide a means for recording all data collection activities performed at a site.
Entries will be as descriptive and detailed as possible, so that a particular situation could be
reconstructed without reliance on the collector's memory.
All measurements made and a detailed description of each sample collected are recorded. All
logbook entries will be made with indelible ink and legibly written. The language will be factual
and objective. No erasures are permitted. If an incorrect entry is made, the data will be crossed out
with a single strike mark, initialed, and dated. Entries will be organized into tables if possible. The
following guidelines will be implemented for all logbooks:
•
•
Each page will be signed, dated, and numbered
Blank pages will be marked as such
Each entry will be identified with the time (24 hour clock)
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•
•
Logbook extensions (field sheets, purge records, etc.) will be recorded in the logbook
Logbooks will be returned to the field operations manager upon completion, during
periods of absence, and at the end of the investigation
At the beginning of each entry, the following information is recorded: the date, start time,
weather, all field personnel present, level of personnel protection in use on site, and the
signature of the person making the entry
In addition to sample description information, the logbook should also contain full
equipment data including field equipment used, serial numbers, calibration information,
and pertinent observations
Deviations from this Field Operations Plan or other plans will be noted
Communications with coordinating officials will be recorded
All logic behind field decisions will be supported in the logbook
Documentation for samples collected will include the following at a minimum:
Description of sample location
Names of samplers
Time and date of sample collection
Intended analyses, containers, and preservatives
• CLP traffic report sample numbers, if applicable
• Laboratory destination
• Sample tag numbers
• Pertinent observations
Field measurements
In addition, photographs of each different sampling event will be recorded. The photograph
selection will be determined by the field operations manager during the sampling event. At the time
of sample packaging and shipment, the shipper's airbill number and chain-of-custody number will
be recorded in the field logbook.
3.2.13.2 Chain-Of-Custody
A chain-of-custody record will be completed for all samples requiring laboratory analysis. The
laboratory will designate the project number, and the field operations manager will maintain it. The
following guidelines will be implemented to complete the record:
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•
•
•
•
•
•
•
Enter the project name
Sample collector signs the form
Record the station number (sample code) for each sample
Record the d_ate and time of sample collection
Indicate whether the sample was a grab or composite
Give a brief narrative description of the sample collection station
Indicate the total number of containers
Enter the individual number of each type of container under the corresponding analysis
Record the tag numbers
Relinquish the sample to the laboratory or shipper. If hand-delivered, request the recipient
sign. Because shipping companies will not sign-off, the name of the shipping company
should be recorded under "received by"
Enter the airbill number under remarks, if applicable
The serial number for each chain-of-custody form will be recorded in the field logbook.
If samples are sent to CLP laboratories, a sample identification number will be written in indelible
ink on each sample container collected for analysis. A Sample Traffic Report/Chain-of-Custody
Form will then be completed for each cooler of samples for each designated laboratory. The
information that must be entered on the form is detailed in the User's Guide to the Contract
Laboratory Program, December, 1988. A copy of this guide will be onsite. The Traffic
Report/Chain-of-Custody Form must be secured to the inside of the shipping cooler prior to
shipment. Shipping coolers will be secured with fiber tape, and custody seals will be placed across
cooler openings. A copy of the custody record will be retained in the CDM Federal project file.
Each time the samples are transferred to another person, signatures of the persons relinquishing and
receiving them, as well as the time and date of transfer will be completed in the appropriate spaces
on the Traffic Report/Chain-of Custody Forms. This will complete sample transfer.
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It will be the CLP laboratory's responsibility to maintain internal logbooks and records that provide
a custody record throughout sample preparation and analysis. To track field samples through data
handling, COM Federal will maintain photocopies of all traffic reports and chain-of-custody records.
If samples are sent to SESD for analysis, a COM Federal chain-of-custody fonn will be used in place
of the Traffic Report/Chain-of-Custody Fonn.
Samples sent to the COM Federal subcontracted laboratory will be wrapped in ziplock bags and
placed in a cooler with ice. A chain of custody fonn issued by the laboratory will be used to
document custody of the samples. The samples will either be shipped by express courier or
delivered directly to the laboratory.
3.2.13.3 Sample Labels
For each sample to be analyzed, a separate sample tag will be completed and secured to the water
samples. The following guidelines will be used to complete each sample tag:
I. Project code refers to the case number designated by the laboratory for each project. This
code may be obtained from the field operations manager.
2. Station number refers to the sample code.
3. Record the month, day, and year.
4. Record the sample time.
5. Designate the sample as grab or composite (X).
6. Give a narrative description of the sample location.
7. Both samplers must sign the tag.
8. Indicate (X) if preservatives are in the sample.
9. Indicate (X) the type of analyses to be perfonned on the sample.
' 10. Under remarks, enter HWSI (Hazardous Waste Site Investigation), water.
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11. The sequential number from the tag should be entered on the sampling field sheet.
12. The sample number label from the inorganic or organic traffic report must be stapled to
the back of the tag.
3.2.14 DECONTAMINATION PROCEDURES
Soil boring and monitoring well installation equipment will be decontaminated by the drilling
. subcontractor upon arrival on-site and between boring locations to avoid the possibility of cross-
contamination.
Decontamination procedures will be performed on decontamination pads located at or near each of
the source areas. The decontamination area will be selected on the basis of the following criteria:
Accessibility to heavy equipment
Fate of water and soap solutions used during decontamination
The following decontamination procedures will be used for all nonplastic equipment that may
potentially contact the environmental media to be sampled. All equipment will be appropriately
decontaminated prior to sample collection. Examples of such equipment include bailers, split
spoons and augers, well screens, and Pyrex bowls, etc. The decontamination procedure is detailed
below.
1. Remove gross contamination and particulates by brushing with a potable water/phosphate-
free, laboratory grade soap solution. Heavy equipment (drill rigs, tools, backhoe, etc.) will
also be steam cleaned or cleaned with a high-pressure washer.
2. Rinse thoroughly using potable water.
3. Rinse thoroughly with deionized water. (Note: A higher grade can be substituted.)
4. Inspect thoroughly for visible particulates and/or contamination. Repeat steps I and 2, if I necessary.
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5. Rinse twice with pesticide-grade isopropanol and allow to air dry.
6. Rinse twice with organic-free water (stored in a glass or stainless steel container) and
allow to air dry.
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7. Wrap equipment with aluminum foil to prevent contamination during transport and
storage. Polyethylene sheeting may be used for large items such as drill pipe.
Sensitive and/or plastic equipment. if used, will be subject to the procedure described above, except
for step 5, which is not performed.
The following is the standard procedure for field cleaning augers, drill stems, rods, tools, and
associated equipment.
1. Clean with tap water and soap, using a brush if necessary, to remove particulate matter and
surface films. Steam cleaning (high pressure hot water with soap) may be necessary to remove
matter that is difficult to remove with the brush. ·
2. Rinse thoroughly with tap water.
3. Remove from the decontamination pad and cover with clean, unused plastic. If stored
overnight, the plastic should be secured to ensure that it stays in place.
All downhole drilling equipment that will be used directly over the boreholes that have a protective
coating such as paint will be sandblasted before arriving at the site. All drilling equipment will then
be decontaminated at the site before drilling each new boring.
All alcohol decontamination by-products will be containerized in a closed-top container. After the
conclusion of the investigation. disposition of the alcohol will be determined.
3.2.15 WASTE HANDLING
The Waste Management Plan (WMP) for the North Belmont PCE Site documents the management
of investigation-derived waste generated during implementation of the field work for the remedial
design for the site. The WMP is located in Section 3.0 of the Field Operation Plan (COM Federal
1998).
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3.2.16 QUALITY ASSURANCE/QUALITY CONTROL
The QAPjP cover the activities and quality assurance (QA)/QC procedures necessary to meet the
DQOs defined for the field investigation. The QAPjP is located in Section 2.0 of the Field
Operations Plan (CDM Federal 1998).
3.2.17 HEAL TH AND SAFETY
The Health and Safety Plan for the North Belmont PCE Site is located in Section 4.0 of the Field
Operations Plan (CDM Federal I 998).
3.3 TASK 1-DA TA REVIEW
A final review of all historical data will confirm existing data points and develop and define
contaminant flow paths to assure initial well selections are appropriate. The additional data review
will focus on the hydrogeology, chemistry, and physical aspects of various wells and contaminant
flow paths in the three aquifer zones at the Site with the view to assure initial well selection.
Although much of this information has been documented in the preliminary site conceptual model
(Section 1.3), any additional review of existing data will be used to refine the work plan.
The review of existing data will focus on the presence of preferential flow paths at the Site, the
integrity of selected groundwater monitoring wells, and an accurate description of the site lithology.
Potential preferential flow paths will be investigated by evaluating site and utility drawings and
other available data (i.e., soil permeabilities and grain size). Inspection of boring logs will be
performed to better understand the geology and hydrogeology at the Site. Historic data may
sufficiently define some of the hydrogeological parameters needed for modeling of the fate and
transport of the plume and the potential for full implementation of enhanced in situ bioremediation.
An accurate site conceptual model is essential for selecting an appropriate remedial technology.
Should enhanced in situ bioremediation and in-well vapor stripping not be effective remedial
technologies for the Site, then the site conceptual model will help in the selection and development
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of alternative remedial technologies. The site conceptual model should be continually updated to
reflect the latest, most-accurate understanding of the Site.
This task also contains time to contract laboratories, order supplies, develop field record forms,
contract drillers, and other items to mobilize into the field.
3.4 TASK 2-SAPROLITE AQUIFER CHARACTERIZATION
3.4.1 SUBTASK 1-DELINEA TION OF GROUNDWATER CONTAMINANT PLUME
Delineation of groundwater contaminant plumes and parameters affecting in situ biological
processes within both Source Area A and Source Area B will be performed using DPT methods.
DPT sampling methods are alternatives to methods that require drilling. As a result, DPT sampling
methods allow for quick, relatively easy sample collection at a substantial cost savings to common
drilling techniques. DPT sampling methods will be used as a preliminary screening tool for
collection of multiple groundwater samples to delineate the extent (i.e., spatial distribution) of
contaminants within both source areas. Data collected during DPT sampling will be used later to
strategically identify locations for installation of permanent groundwater monitoring wells (see
Subtask 2). This approach will ensure that proposed groundwater monitoring well locations are
within areas of interest.
Direct-push sampling equipment (e.g., Geoprobe or Hydropunch) will be used to collect
groundwater samples along a downgradient flow path from each source area. Discrete groundwater
sampling devices, such as Geoprobe's Screen Point 15 (or similar), will be driven to approximately
10 feet below the groundwater table. Groundwater elevations range between 3 and 35 feet below
groundsurface (bgs), with most values between 20 and 30 feet bgs (RI Report, USEPA 1997c).
These groundwater elevations are expected to be within sampling depths of the DPT methods. Upon
driving the sampler to the desired depth, the screen will be exposed and groundwater samples
collected. Tubing attached to the sampler and exposed at the ground surface will be left in place for
collection of additional groundwater samples at a later time, if desired. This tubing will removed
upon demobilization activities. Collected groundwater samples will be analyzed using an on-site
laboratory for groundwater VOC concentrations. In addition, groundwater will be collected and
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analyzed for all other analytes listed in Table 3-2. Special considerations for each source area are
mentioned below.
Source Area A
Up to 20 DPT temporary sample points will be installed within the saprolite aquifer of Source
Area A. These points will be concentrated in the source area and along a downgradient flow path
that extends in a northeasterly direction from this facility. The first downgradient sample point will
be installed 200 feet downgradient from the former STW-3 location. Additional DPT points will
be installed at 400-foot downgradient increments from previous locations. Sampling along the
downgradient flow path will be terminated upon achieving non-detect voe concentrations.
Additional DPT sample points will be installed at locations transverse to the direction of
groundwater flow to determine the lateral extent of contamination. These samples will extend
laterally at I 00 foot intervals along one or more transects.
Source Area B
Up to 20 DPT temporary sample points will be installed within the saprolite aquifer of Source
Area B. These points will be concentrated in the source area, which is located near the existing
MW IO location, and along a downgradient flow path that extends in a north to northeasterly
direction from this location. The first downgradient sample point will be installed 200 feet
downgradient from the former MW IO location. Additional DPT points will be installed at 400 foot
downgradient increments from previous locations. Sampling along the downgradient flow path will
be terminated upon achieving ~on-detect voe concentrations. If voe concentrations are still
detected at 1400 feet downgradient from MWI0, or ifVOe concentrations are increasing along the
flow path, then further sample collection along the downgradient flow path will be terminated due
to assumed influences of contaminants from the Source Area A location. Additional DPT sample
points will be installed at locations transverse to the direction of groundwater flow to determine the
lateral extent of contamination. These samples will extend laterally at I 00 foot intervals along one
or more transects.
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3.4.2 SUBTASK 2-SELECTION OF MONITORING WELL LOCATIONS
Groundwater voe results will be immediately evaluated to determine the downgradient and lateral
extent of contamination. Based on the extent of contamination, field decisions will be made as to
the proposed locations of permanent groundwater monitoring wells. A minimum of six, and up to
ten, locations will be strategically selected for installation of groundwater monitoring wells. It is
anticipated that proposed locations along a contaminant flow path will be spaced every 200 feet
within contaminated regions. with one well at least 200 feet downgradient of detectable contaminant
concentrations. Additional locations will lie in a transverse direction to the contaminant plume, with
location and spacing highly dependent on DPT screening activities. All monitoring wells will be
installed during Task 4 activities.
3.5 TASK 3-SAMPLE ACQUISITION AND HANDLING
Groundwater samples will be collected at all monitoring wells and residential wells identified in
Table 3-1, and at temporary DPT locations installed during Task 2 activities. Groundwater will be
analyzed for all voe and bioremediation parameters as outlined in Table 3-2. Soil samples will
be collected at each newly installed groundwater monitoring well. A limited number of soil samples
will be analyzed for parameters outlined in Table 3-2 and described in Section 3.2.2.
3.6 TASK 4-GROUNDW ATER WELL INST ALLA TI ON
3.6.l SELECTED LOCATIONS
· Installation of permanent groundwater monitoring wells include:
• selections determined during Task 2 activities for the Saprolite aquifer
• one location within the central portion of the top of bedrock aquifer PCE contaminant
plume (Figure 1-12);
The installation of a permanent groundwater monitoring well in the top of bedrock aquifer is due
to the limited sample locations in this central plume area. The location is approximately I 00 feet
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directly south of the former TW3 location (Figure 1-12). A groundwater monitoring well at this
location will be used to monitor contaminant concentration trends along a downgradient flow path
from existing monitoring well MW6, where the highest PeE concentration in the top of bedrock
aquifer was recorded (2,500 µg/L; October 1996).
Approval of proposed monitoring well locations will be acquired from the USEPA prior to their
installation. Additionally, residential structures will be identified, utility lines will be located and
marked, and potential obstructions such as trees, boulders, or infrastructures will be noted.
3.6.2 SOIL BORING AND VERTICAL PLACEMENT SELECTION
Soil borings will be advanced to the bottom of the saprolite lithology at each well installation
location. During the boring advancement, groundwater and saturated soil samples will be collected
at IO foot intervals for analyses identified in ·Table 3-2. Soil samples will be classified for lithology
and screened by the eDM geologist for voe contamination using a photoionization detector (PID).
The soil sample exhibiting the highest PID reading per borehole will be selected for laboratory voe
analysis; if organic vapors are not detected, selection of the soil sample will be based on the
discretion of the eDM geologist. Groundwater samples will be immediately submitted to the on-site
laboratory for voe analysis.
All boreholes will be advanced until one or more of the following criteria are met: (I) the borehole
has been advanced beyond the saprolite lithology and into the top of bedrock, (2) PID readings
indicate two successive decreases in organic vapor concentrations, or (3) voe analyses, if available,
indicate two successive decreases in concentrations. In addition, one borehole will be advanced into
the top of bedrock aquifer, where a soil core will be collected for use in the microcosm study.
PID and voe data collected at each borehole will be used for determining the desired depth of well
screens. Upon termination of borehole advancement, auger casings will be left in-place until all
groundwater voe results for the borehole have been obtained. Depths will then be selected for
placement of well screens such that the screened interval lies within the highest contaminated region
at each borehole location. If the desired screen depth is shallower than the total depth of the
borehole, then the borehole will be grouted to achieve the appropriate well depth.
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4.0 IN-WELL AIR STRIPPING
4.1 DESCRIPTION OF TECHNOLOGY
In-well or in situ vapor stripping is a relatively new in situ remedial technology that reduces
concentrations ofVOCs that are adsorbed to soils or dissolved in groundwater. Variations ofin situ
vapor stripping include air sparging conducted alone and air sparging combined with vapor
extraction.
Air sparging is the injection of contaminant-free air into the subsurface saturated zone, enabling a
phase transfer ofVOCs from a dissolved state to a vapor phase. The air is then vented through the
unsaturated zone. When the air sparging is performed in conjunction with vapor extraction, negative
pressure is created in the unsaturated zone. The extracted vapors are treated as necessary and then
discharged to the atmosphere or re injected to the subsurface. The introduction of air from the_ air
sparging increases the dissolved oxygen content in the affected groundwater, and may accelerate
aerobic biodegradation.
4.2 PRESENTATION OF VENDOR SUBMITTALS
Site information and contaminant concentrations contained in the RI Report (USEPA 1997c) were
provided to vendors to assist in the preparation of cost estimates. Responses for technical approach
and estimated costs for in-well air stripping at the Site were received from four vendors. Cost
estimates for a pilot study were received from all vendors. Costs for a full scale treatment system
were provided by two vendors. Each technology is identified by a specific trade name. The trade
names are as follows: NoVOCs'", UVB, DDC, and QUICK PURGE®. Discussions with vendors
associated with the NoVOCs'", UVB, and DDC technologies indicated that some of the patent and
licensing agreements relevant to these technologies are currently in a state of flux, partially due to
similarities in design. Most vendor approaches are generic in nature at this time, however, specific
modifications can be made to most remediation systems to accommodate project-specific needs.
A summary of vendor submittals is contained in Table 4-1. The individual vendor technology and
project approach are discussed below. Additional information provided by each vendor is contained
in Appendix A.
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Table 4-1
Summary of Vendor Supplied Cost Estimates for Pilot Testing
Technology Trade
Name UVB NoVOCsTM
Technology Under pressure in-Pressurized in-well
well stripping system stripping system
Estimated pilot study $150.000--175.000 $100,000--$150.000
cost
Estimated number of One 6-inch diameter Four 6-inch diameter
wells to be PVC-app. depth l00 PVC-app. depth 130
constructed for pilot feet feet
testing
Length of pilot study 6 months 6 months
Operating costs for Labor-$12.000. Labor-$12.000
length of pilot study" Elcctric-$2400. Electric-$2400
Sample Sample
analysis-$2400 analysis-$4 700
(Total is $16.S0D--(Total is $19,I0D--
used $17.000) used $19,000)
Total estimated $167.000--192.000 $119,000--159,000
vendor and operating
costs for pilot test
Special Focus of remediation Focus of remediation
considerations is on top of bedrock is the bedrock
aquifer. aquifer.
Ability to add ozone Yes Yes
a Operating costs based upon the following assumptions:
Labor-40 hrs per month @ $50/hr.
Electric-$400/month,
DDC
Pressurized in-well
stripping system
$99,000
One 8-inch diameter
PVC-app. depth l00
feet
1-0 months
Labor-$12.000
Electric-$2400
Sample
analysis-$2400
(Total is $16.S0D--
used $17.000)
$116,000
Focus of remediation
is on the top of
bedrock aquifer.
Air can be reinjected.
Yes
QUICK PURGE®
High intensity air
sparging
$25,000
None-,vou\d use
existing wells for
pilot testing
3-5 days
Included in vendor
costs
$25.000
Pilot study would be
conducted in all three
aquifers. No
treatment of vapors
proposed.
Yes
Sample analyses-I sample per month per well plus 2 QC samples per even@$130/sample (YOCs only). Costs for
containerization and disposal of wastes generated during pilot study (drill cuttings. development water. and purge water)
are not included in estimates.
NOVOCS"
NoVOCs'"-Description of Technology
NoVOCs'" is an in-well stripping system that combines air sparging and vapor extraction. The
NoVOCs'" is considered to be a pressurized system which requires the installation of wells with two
screened intervals. The screened intervals are located at the top and bottom of the aquifer. The
bottom screen, referred to as the lower extraction screen, is the entry point-for contaminated
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groundwater. The top screen, referred to as the recharge screen, contains a packer or deflector plate
to prevent further upward movement of groundwater and is located slightly above the
groundwater/vadose zone interface. Pressurized air is delivered into the submerged section of the
well by a bubble diffuser. The resulting air/water mixture, which is lighter than water, rises in the
well casing. The air/water flow that rises up in the well allows for optimal contact between
groundwater and the air bubbles, resulting in volatilization ofVOCs. When the air/water mixture
encounters the packer or deflector plate, the groundwater is diverted back to the aquifer through the
top screen. This groundwater has a lower VOC concentration and a higher dissolved oxygen content
as a result of the air injection into the well. A portion of the recharge screen located above the
packer or deflector plate acts as a preferred pathway for vapors due to the negative pressure induced
by a vacuum blower. The vapors are vacuum extracted for aboveground treatment and discharge.
NoVOCs '" Project Approach and Estimated Costs
The focus of the remedial effort with this technology is the bedrock aquifer.
The cost estimate provided by the vendor for a pilot test at the site using the NoVOCs'" technology
is$ 100,000 to$ I 50,000. This includes the installation of four 6-inch-diameter PVC dual-screened
wells (completion depth of 130 feet) and the setup of one equipment trailer containing the necessary
blowers, vacuum extraction equipment, ancillary equipment, GAC system and controls, and system
startup. The length of the pilot test would be approximately six months. Operating costs were not
provided by the vendor. Operating costs for a six month pilot study are estimate_d at $17,000. A
breakdown of the estimated operating costs is contained in Table 4-1. The total for the estimated
vendor and operating costs ranges from $119,000 to $159,000. The costs associated with
containerization and/or disposal of drill cuttings, excavation spoils, and development water are not
included in the cost estimate. Considering the total cost of oversight and reporting, the cost to test
this technology is in the $200,000 range.
The cost estimate supplied by the vendor for a full-scale treatment system is $1,400,000. This cost
includes the instaUation of forty-four 6-inch-diameter PVC dual-screened wells (completion depth
of 130 feet) and the deployment of approximately IO equipment buildings containing the blowers,
vacuum extraction equipment, ancillary equipment, GAC system, and controls. Piping would be
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installed underground. The wells would be flush mounted to minimize intrusion in the residential
neighborhood. The wells would be placed in a checkerboard pattern throughout the delineated
plume area at a spacing of approximately 260 feet. The system will require a 220-volt, 3-phase
electric supply and access to phone lines. The estimated period of system operation is 5.25 years
to 6.5 years. Operating costs were not provided by the vendor. Using the same unit costs for labor,
electricity, and sample analyses as for the pilot testing, operating costs over a six-year operating
period are estimated at $650,000. Replacement or repair of equipment are not included in the
operating cost estimate, nor are costs associated with containerization and/or disposal of drill
cuttings, excavation spoils, and development water associated with installation of forty-four wells
and associated underground piping. A more accurate cost estimate for full-scale deployment of this
technology would be made at the completion of the pilot test.
UVB Description of Technology
UVB (Unterdruck-Verdampfer Brunner) is an in situ stripping technology that has been used in
numerous sites in Germany and has recently been introduced into the United States. UVB is the
trade name for a vacuum vaporizer well system, consisting of an extraction well with two screened
intervals ( one at the bottom of the aquifer and one at the top of the aquifer). Greater emphasis is
placed upon vacuum extraction with this technology. The upward movement of air and water in the
well is initiated by vacuum rather than by positive displacement as in some other in situ stripping
such as NoVOCs'".
The UVB system is based on a vacuum at the wellhead which induces air flow to a pinhole plate
located below the water table. The pinhole plate is connected to a standpipe which is open to the
atmosphere. Vacuum applied at the wellhead lifts the water level in the well, and air flow is induced
down the standpipe and out the pinhole plate. The rising bubbles_ cause a small amount of water to
flow upward in the well. The upward flow of groundwater through the well results in stripping of
VOCs from the groundwater and increase in dissolved oxygen concentrations. Vertical flow in the
well can be increased by pumping. Vapors are extracted via vacuum and treated at the surface
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before discharge. The direction of flow induced by pumping can be upward or downward in the
well, based upon project-specific requirements.
UVB Project Approach and Cost Estimates
The focus of the pilot test would be on the top of bedrock aquifer, rather than the bedrock. The
vendor felt that there were too many uncertainties associated with the bedrock aquifer and
contaminant pathways.
The cost estimate for a pilot test at the site, based upon the standard UVB approach, ranges from
$150,000 to $175,000. The cost includes the installation of one dual screened 6-inch-diameter PVC
well (approximate depth I 00 feet), provision and deployment of surface equipment, and system
startup. The estimated length of the pilot test is six months. Operating costs were not provided by
the vendor. Estimated operating costs for the pilot test are approximately $17,000. The breakdown
for the operating costs is contained in Table 4-1. The costs associated with containerization and/or
disposal of drill cuttings, excavation spoils, and development water are not included in the cost
estimate. Total costs of the pilot test for this system would likely be in excess of $200,000. A cost
estimate for a full-scale treatment system was not provided by the vendor because the final design
of a full-scale treatment system is contingent upon the results of the pilot testing.
DDC
DOC Description of Technology
DOC (Density Driven Convection) is an in-well stripping system that combines air sparging with
vacuum extraction. Similar to the NoVOCs'" approach, the DOC system is also considered to be a
pressurized system. The technology requires the installation of dual-screened wells. The screened
intervals are located at the top and bottom of the aquifer. The upper screened interval straddles the
groundwater/vadose zone interface. Air is injected into the well casing through an air line. The
introduction of the air creates an upward vertical gradient that draws water into the lower screened
interval and returns aerated groundwater out through the upper screened interval. The air movement
in the groundwater acts as a stripping agent for the VOCs, resulting in lower VOC concentrations
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with each pass through the wells and an increase in dissolved oxygen concentrations. Similar to the
technology utilized by the NoVOCs'" system, vapors generated during the stripping process would
be extracted from the vadose zone through the upper portion of the upper screened interval and
treated by GAC units at the surface. After GAC treatment, the air would then be re injected into the
aquifer to continue the air stripping process. Reinjection of the extracted air is optional. The closed
air system has been used at sites where calcium precipitation has been a concern.
DOC Project Approach and Cost Estimates
Cleanup remedies with this technology will focus upon the top of bedrock aquifer. No attempt will
be made to treat the bedrock. The vendor felt that there were too many uncertainties associated with
con tam in ant transport in the bedrock.
The estimated cost to conduct a pilot test at the Site is approximately $99,000. This estimate
includes the installation of one 8-inch-diameter PVC dual screened we·II (approximate depth
I 00 feet) and the fabrication of one equipment trailer containing blowers, vacuum extraction
equipment, GAC system, ancillary equipment and controls. The length of the pilot test is estimated
to range from one to six months. Labor costs included in the estimate are limited to startup and
system optimization. Labor costs for operating the system during the pilot test were not provided
by the vendor. Estimated operating costs for the pilot test range from approximately $2,800 for one
month of operation to $17,000 for six months of operation. A breakdown of the operating cost
estimate is contained in Table 4-1. The costs associated with containerization and/or disposal of
drill cuttings, excavation spoils, and development water are not included in the cost estimate. Total
costs of the pilot test including oversight and reporting are likely to be in the $125,000 range.
The vendor cost estimate for a full-scale treatment system at the site is approximately $2,600,000.
The full-scale treatment system includes the installation of sixty six 8-inch PVC dual-screened wells
(approximate depth I 00 feet) and associated piping, fabrication of seven equipment sheds containing
the blowers, vacuum extraction equipment, GAC system, ancillary equipment, and controls, and
system startup. The vendor did not specify the length of time for operation of the full scale
treatment system. Operating costs for the full scale treatment system were estimated at
approximately $607,000 for a six year period. As with the pilot testing, containerization and
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disposal of investigative derived wastes associated with installation of the 66 wells are not included
in the cost estimate. A more accurate cost estimate for full-scale implementation of this technology
would be made after completion of the pilot test.
QUICK-PURGE®
OUICK-PURGE®-Description of Technology
QUICK-PURGE® is a patented modified version of conventional air sparging. It is a high intensity
air sparging method that places maximum stress upon the groundwater and soil within the radius of
influence of the air entry point. The technology involves the injection of contaminant free air into
the subsurface saturated zone. VOCs are transferred from a dissolved phase to a vapor phase. The
air is vented through the saturated zone. The QUICK-PURGE® technique consists of the application
of a large volume of uncontaminated air under higher operating pressures than most other air
sparging techniques. Capture and treatment of the vapors are not typically performed with this
technique. The vendor states that better results are achieved though cyclical operation rather than
continuous operation. Cyclical operation in low permeability formations typically consists of one
operating period of four hours per day followed by system shutdown. The cyclical operation also
minimizes potential channeling in unconsolidated formations .. Equipment required for this
technology includes a portable air compressor and temporary piping. The air compressor is fueled
by gasoline or diesel, thereby eliminating the need for an electrical power source. Because the
equipment is mobile, there is flexibility for changing locations of the monitoring wells during pilot
testing if needed.
The vendor claims that site restoration using the QUICK-PURGE® technology is greatly accelerated
when compared to conventional methods. The vendor stated that QUICK-PURGE® has reduced
contaminant levels at other sites to below detection limits in a matter of days or weeks versus the
time frame of years that are typically associated with conventional cleanup methodology such as
pump and treat. While the vendor acknowledges that this technology has not been attempted in
bedrock, he believes that the air injected into the bedrock aquifer will follow the preferred flow path
of contaminants, and that the potential exists for the stripping of contaminants in bedrock.
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OUICK-PURGE"-Project Approach and Cost Estimate
. Pilot testing would be conducted in three existing monitoring wells at the Site to determine if the
technology is effective in reducing contaminant concentrations in groundwater. Each of the three
aquifers at the Site (saprolite, top of bedrock, and bedrock) would be subjected to pilot testing by
the QUICK-PURGE°' method through testing of one existing monitoring well in each aquifer.
Preferably, the three monitoring wells would be located close together to determine if air sparging
at one depth influenced contaminant concentrations at other depths. No additional wells would be
installed for the pi lot testing.
The cost estimate for conducting the pilot test is $25,000. The anticipated length of the pilot test is
3-5 days. Groundwater samples would be collected from each of the three wells and analyzed for
VOC concentrations before and after pilot testing is conducted in each well to determine if a
measurable reduction in VOCs is apparent. Air injected into monitoring wells located in the
saprolite and top of bedrock aquifers will migrate upward from the screened interval through the
aquifer and the soil at a 45° angle from vertical. The air introduced into the bedrock aquifer is
anticipated to follow the contaminant pathways in the bedrock such as natural fractures. Operating
costs for the pilot test are included in the vendor cost estimate. Containerization and disposal costs
for purge water generated during groundwater sample collection are not included in the vendor cost
estimate. Considering the costs, as well as oversight and reporting, the pilot test costs would likely
be in the $50,000 range.
A cost estimate for a full-scale treatment system was not provided by the vendor because the final
design of a full scale treatment system is contingent upon the results of the pilot testing.
4.3 EVALUATION OF VENDOR SUBMITT ALS
The effectiveness of any remedial technology is influenced by multiple factors specific to each
individual site. In situ or in-well air stripping has shown some promise at other locations throughout
the country. Technical and logistical challenges at the Site include the presence of groundwater
contaminants in three separate aquifers, particularly in the bedrock aquifer, and the location of the
groundwater plume in a residential area.
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The technical and costing approach is different for each vendor; therefore, direct and equal
comparison of submittals is not possible. The evaluation focuses primarily upon the pilot test
approach at this time because it is anticipated that any technical approach and cost estimate for a
full-scale treatment system would be modified, perhaps extensively, after the data from the pilot test
are evaluated. Significant advantages and disadvantages that have been identified for each vendor
technology are summarized in Table 4-2.
Table 4-2
Evaluation of In Situ Technologies
NoVOCsn1 UVB DDC QUICK-PURGE®
Focus of cleanup Bedrock aquifer Top of bedrock Top of bedrock All aquifers-saprolite, top
aquifer aquifer of bedrock. and bedrock.
Advantages Matches ROD Matches ROD Matches ROD Low-cost. Short duration
requirements for requirements for requirements for pilot test. Potential for using
selected remedy. selected remedy. selected remedy. existing monitoring wells as
Extracted air can be air injection points. Vendor
reinjected. stated that the technology
has cleaned up other sites to
"no further action'' criteria
in unconsolidated
formations. Equipment is
portable-does not require
installation of underground
piping.
Disadvantages Construction-Construction-Construction-Effectiveness in bedrock
access and access and access and unknown. If existing
disruptions in disruptions in disruptions in monitoring wells are not
residential residential residential usable for this technology,
neighborhood. neighborhood. neighborhood. additional wells may have
Operation -noise Operation -noise Operation -noise to be installed to use the
considerations in considerations in considerations in QUICK-PURGE®
residential residential residential approach.
neighborhood. neighborhood. neighborhood.
In addition to the technical and economic aspects of groundwater cleanup, the logistics of
implementing a groundwater cleanup in a residential area need to be considered. Disruption of the
residential area during well construction, piping installation. and deployment of surface equipment
will be unavoidable. The location of existing underground utilities may also influence accessibility
for new well construction and piping installation.
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Although the actual in-well stripping takes place underground in a well, associated surface
equipment, such as blowers. compressors, and pumps need to be located in the vicinity of the wells.
Although the buildings that contain the blowers and controls are insulated, noise from continuous
or semi-continuous blower operation could be disturbing in a residential neighborhood, particularly
if multiple surface units are deployed.
After considering the technical uncertainties, the magnitude of potential cleanup costs, and the
logistical difficulties associated with implementing a groundwater cleanup at the Site, hot spot
reduction may be a viable alternative. Hot spot reduction would concentrate groundwater cleanup
efforts in the most contaminated areas within the plume and could potentially remove a significant
quantity of contaminant mass, and minimize inconveniences and disruptions to the residential area.
98-03S/77 40-07610824 4-10
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5.0 REFERENCES
Air Force Center for Environmental Excellence (AFC EE), 1996. Technical Protocol for Evaluating
Natural Allenuation of Chlorinated Solvents in Groundwater. November.
Bradley, P. M., and F. H. Chapelle, 1997. Kinetics of DCE and VC Mineralization Under
Methanogenic and Fe (111)-Reducing Conditions. Environmental Science and Technology.
Vol. 31, No. 9, pp. 2692-2696.
Bradley, P. M., and F. H. Chapelle, 1998. Effect of Contaminant Concentration on Aerobic
Microbial Mineralization of DCE and VC in Stream-Bed Sediments. Environmental Science
and Technology. Vol. 32, No. 5, pp. 553-557.
COM Federal Programs Corporation, 1998. Final Field Operations Plan Remedial Design for the
North Belmont PCE Superfund Site, North Belmont, North Carolina. June.
Davis, R. K., D. T. Pederson, D. A. Blum, and J. D. Carr, I 993. Atrazine in a stream-aquifer
system -estimation of aquifer properties from atrazine concentration profiles. Groundwater
Monitoring Review, Spring, 1993. p. 134-141.
Domenico, P.A. and F. W. Schwartx, 1990. Physical and Chemical Hydrogeo/ogy. John Wiley and
Sons, New Yark.
Freeze, R. A. and J. A. Cherry, 1979. Groundwater. Prentice Hall, Inc., Englewood Cliffs, New
Jersey.
Hamed, 1989.
LeGrand and Mundoff, 1952.
USEPA, 1997a. "North Belmont PCE Site. North Belmont, Gaston County, North Carolina: Record
of Decision." September.
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USEPA, 1997b. "Statement of Work for Technical, Engineering, and Contractual Support Services
for the Remedial Design at the North Belmont PCE Superfund Site, North Belmont, Gaston
County, North Carolina." August 27.
USEPA, 1997c. "North Belmont PCE Site, North Belmont, Gaston County, North Carolina:
Remedial Investigation Report." June.
USEPA, 1997d. "North Belmont PCE Site, North Belmont, Gaston County, North Carolina:
Feasibility Study Report." July.
9R-03517740-076/0824 5-2
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I IN SITU VAPOR STRIPPING
I VENDOR INFORMATION
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NoVOCsTM
IN-WELL STRIPPING
TECHNOLOGY
Metcalf & Eddy, a leading provider of environmental
services and technologies. is now offering the
No VOCs system for cost-effective in-situ remediation
of groundwater contaminated by volatile organic
compounds (VOCs). As a licensee of EG&G
Environmental. developer and integrator of this
innovative technology. Metcalf & Eddy is applying
No VOCs to a broad range of VOC-contaminated
aquifers as an alternative to pump & treat.
THE NoVOCs™ ALTERNATIVE
'
NoVOesT" (U.S. Pat No. 5,180,503) is an
innovative technology for in-situ remediation of
aquifers impacted by volatile organic .
compounds ( voes).
Based on the proven physical principles of
in-well stripping and groundwater
recirculation. No VOCs can both contain
and treat plumes containing multiple
contaminants, thereby covering a very
wide range of site and contamination
situations.
NoVOes provides a reliable and
systematic alternative to pump and treat
for remediation of voe contaminated
aquifers.
NoVOCs™ IN-WELL STRIPPING
A NoVOes well comprises two screened intervals,
located respectively at the bottom and top of the
contaminated aquifer. as shown in Figure I.
Pressurized air is delivered by a diffuser in the
submerged section of the well. The resulting air-
water mixture, lighter than water, rises in the well
casing, and in tum draws more groundwater into the
well from the aquifer, achieving "air-lift" pumping.
The air-water flow rising up the well allows for
optimal contact between groundwater and air
bubbles, resulting in volatilization of dissolved
voes.
Stripping efficiency. controlled by air-water ratio and
contact time, can be varied according to voe levels.
After reaching the desired elevation, the air-water
flow separates against a packer or deflector plate.
The water, stripped of its voes and saturated in
dissolved oxygen. percolates back to the aquifer
through the recharge screen. The vapors are vacuum-
extracted for aboveground treatment by carbon
absorption, biofiltration. catalytic oxidation or other
means.
The reinfiltrated groundwater tends to follow a
toroidal (donut-shaped) circulation pattern leading
back to the intake screen. This flow pattern does not
cause drawdown nor rise of watertable levels. and
allows groundwater to undergo multiple stripping
cycles while it flows past the well.
Injection
Blower
Stripped voe Vapors
Vapor
Treatment
Unit
Key-feat~~;~\,r the Nii'v6c~r~1
alternative are:.
Recircutatlon
Zone
• Robust and broad aJpli~ability.
• Accelefated clean-ups, .
• Capital and operating savings
voe
Contamlm1ted
Water---~
Lower Extraction
Screen
Incoming voe Plume
Figure 1. Basic No voes Well Configuration
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Well pumping rates and well placement are so
designed as to ensure that groundwater particles
undergo the average number of stripping cycles
needed to achieve treatment goals, before they leave
the circulation zone.
The circulated flows are significantly higher than
those of an equivalent pump and treat well, and
insure vertical gradients. This results in an intense
flushing of contaminants from the recirculation zone.
thereby accelerating and enhancing clean-up.
. " ':•:•1,:;.:·,C,''.0:.;.,-,;-.,; •;,:\{(•'••;'•_; ,'.!.i•<":",.(',:'t,:.,,,,.-..,-:·.(.
No VOCs innovariiiely iniegrates tliree we/~". ·.·.· ,
proven physical pri~cipfes: Air:/iftpµ,,;ping, dir-
bubble stripping, groundivate~ reciri:ulaJion ..
ADVANTAGES
Compared to pump and treat NoVOCs"' features:
• No aboveground pumping, treatment and disposal
of groundwater.
• Effective removal of VOCs throughout the
recirculation zone.
• Enhanced in-situ biodegradation in oxygen-
saturated recirculation zone.
• No permitting associated with groundwater
withdrawal and reinjection. ·
• No disruption of water table levels.
Compared to Air-sparging, NoVOCsni features:
• Containment of contaminated groundwater.
• Controlled stripping of VOCs, i.e. no fugitive
omissions.
• Broad applicability
Air Supply/Treatment Trailer->-
. _.. . ' .· : ·-•· ---:-. • • •. ."";· _·. . ·:· . ·--.~ •. ;·,_ ·-.-,~:.'._\::-r., :-No V OCs!}1 · advaritages,result, in:':, t.ower ·costs;'.0b:
. hfgh0e~ p~,f~r/nan~e,f~ter ciean~~ps; a~d;ie(s~;
·-~~vironl11_~ntai i_in[lacts. · ·---~~-{'.'.·f{.}·;/_':(},}(f?Z~~~(ii~f
Added benefits include the diminished mobilization,
or smearing of residual contaminants by fluctuations
in groundwater levels. NoVOCsni vertical flow
gradients have also been shown to accelerate the
dissolution and removal of contaminants trapped in
the soil.
APPLICABILITY
NoVOCsni can treat aquifers containing chlorinated
solvents (TCE. PCE. etc.), BTEX and other volatile
hydrocarbons, including gasoline with MTBE. Table
1 summarizes the key application criteria. As with all
in-situ technologies. aquifer heterogeneity can
impact performance.
Table I : Applicability criteria
Parameter Desired range
Henrv's constant >5.10-' atm-m3/mole
Volatilitv >5 mm He
Solubilitv <20,000 mail
Hvdraulic Conductivitv > IO-' cm/s
Vadose Zone Thickness > 5 ft
Saturated Zone Thickness > LO ft
NoVOCs"'' applies to both unconfined and confined
aquifers, and is well adapted to selectively treat
stratified or sinking plumes.
GROUND'S SURFACE
0115212
Figure 2. Overlapping Treatment Zones
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CONTAINMENT AND TREATMENT MODES
As shown in figure 2, the technology is implemented
by installing multiple NoVOCs wells and
establishing overlapping treatment zones in the
contaminated portion of the aquifer.
[n a containment mode. (see figure 3a) the wells are
placed as a treatment fence near the downstream end
of the moving plume.
[n a treatment mode (see figure 3b), the wells
encompass a larger area of the plume, including its
hotspots. They are designed to accelerate
contaminant mass removal.
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Figure 3a. Plume Containment
r Recirculation
Zone
Figure 3b. Hot Spot Treatment
FLEXIBLE OPTIONS
The simplicity of the NoVOCs concept allows for
great implementation flexibility. Design options
include:
!11-Well Recrcle Srs1e111--Allows for stripping recycle
within the well. thereby enhancing stripping
performance before recharging water to the vadose
zone. This is applicable to special containment
applications.
Retrofit of existing wel/s---For sites in which pump
and treat systems or groundwater wells already exist
and the cost of new wells would be prohibitive.
Horic.onral Well s.,·ste,m---For low permeability
aquifers, long narrow plumes, or where access
problems are encountered.
Free Product Reco,·ery System---For sites requiring
prior removal of LNAPLs.
DNAPL F/11shi11g---For enhanced dissolution
of DNAPLs trapped in capillary and saturated zones.
PREVIOUS EXPERIENCE
Although still perceived as innovative in the U.S.,
recirculating well technology is extensively proven
in Europe, with a track-record of MCL-compatible
clean-up performance.
ln France. a two-well system NoVOCs installed at a
former chemical manufacturing site reduced PCE
concentrations by a 93% in only ten months of
operation. The two NoVOCs wells, coupled with
soil vapor extraction points, removed over 4,000 lbs
of PCE during that period.
In an on-going project, a single NoVOCs well
installed in a heterogeneous aquifer at Edwards AFB
in California has achieved 67% average PCE
reduction in the first 4 months of operations.
Multiple well pilot systems are being installed for
DOD on extensive TCE and PCE plumes at the
Massachusetts Military Reservation on Cape Cod.
Single-well systems are successfully operating on
other sites including, BTEX and TPH plume at
Fairchild AFB, in Washington. Lab pilot tests were
also conducted for implementation on a 1.1.1-TCA
plume at the Hanford DOE site.
NoVOCs.is o'ne of the "To'/if~~i,;;'.,"'\ ·· .... ·•·······
lfc h,iplogies 'uleiitified by DOE: ~M t~-.::····.•·,::.··.:'.·.·::,:;:·•,·.·.·.•··.•:···.•···•:•··,· .. ~:.•.·:·'..•.:.•,:.·.'.·._:_:··,·.·,:_:.·.•.·;·:: 't/ij,edite reniediatio11·a1 DOE sites/}).< :t'·,, . ' ·· .. 1.· • \'·'-•·-"' ' · . ,,,, . .' .,,_. '' ·
COST SAVINGS
The No VOCs rn system produces dramatic savings as
a result of superior efficiency in design and process
over traditional VOC remediation approaches.
Savings originate from lower capital and operating
· costs, as well as reduced duration of clean-ups.
Figure 4 compares NoVOCs costs with those of
common groundwater clean-up alternatives, in
normalized format. for typical BTEX and TCE
contamination situations.
JUN-02-98 17,26 FROM:W.SchulLz 410 798 4404 10:4107984404 PAGE
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In Situ Vertical Groundwater Circulation
and
Soil Flushing
SBP Technologies utilizes a vacuum-vaporized well system, known as lNB technology, to develop
a vertical groundwater circulation cell that captures volatile and semi-volatile contaminants in soil
and groundwater and provides for their removal by a combination of physical air stripping and
bioremediation processes. This technology has the capability of mobilizing and processing
contaminants that are water soluble (both lighter or heavier than water), or exist in a non-aqueous
phase. Therefore, this .technology can provide treatment for a large variety of pollutants. The
number of treatable contaminants can be further increased by installing additional treatment
technologies to the closed loop system such as biofilters, bioreactors, carbon adsorption containers,
metal removal equipment, or nutrient additions, either within the well itself, or externally. UVB
technology has the important advantage over classical Pump and Treat, and, Extraction, Treat and
Reinjection (ETR) technology by providing in situ treatment of contaminants while maintaining an
equilibrium flow in the aquifer, thereby eliminating draw-down and mounding effects.
SBP also utilizes Soil Air Circular Flow (BLK) and Coaxial Groundwater Circulation (CGC)
technologies, which operate on the same basic principles of induced vertical air and water flow for
treating the unsaturated zone and the shallow groundwater zone for sites with a more localized soil
and groundwater contamination. Further description of these technologies follow.
2/9
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·--····-···-· '······ .. ::·Gii:ivt:·:--
·<a~~Oriite· __ .. -· _ .. ~. -
Unsaturated Zone . .
Principles of the UVB System
UVB technology provides for in situ groundwater and soil remediation. The UVB offers several variations
for the treatment of adsorbed., dissolved volatile organic hydrocarbons (VOC) semi-volatile organic
hydrocarbons (SVOC) via a combination of both physical and biological processes. During operation, the
water level rises in the upper section of the well due to reduced atmospheric pressure generated by a blower
and a support pump. This increases the total hydraulic head in the well. Atmospheric air enters the well
through a fresh air pipe connected to the stripping reactor and creates a pressure equilibrium. The incoming
fresh air forms bubbles as it jets through the pin hole plate of the stripping reactor and mixes with the influent
groundwater in the well casing creating an "air lift" effect as the bubble rise and expand. Contaminant mass
is transferred from the water phase to the air phase which rises as expanding bubbles which burst and release
the volatilized contaminant in the upper casing where it is transported by the air flow to a carbon absorption
unit or other off-gas treatment system. Concurrently, a significant hydraulic pressure is produced, forcing the
water horizontally into the aquifer through the upper screen sections located at the top of the plume. The water
moves through the treatment zone both horizontally and vertically before entering the influent screen.
Groundwater flows into the lower screen to compensate for the water removal from the upper section. The
direction of flow can be reversed by reversing the direction of the pump. Thus, a three-dimensional
groundwater flow field (vertical circulation) pattern develops. These flow dynamics and the dimensions of
the capture zone, circulation cell, and release zone can be calculated using design aids based on numerical
sunul"-tions of the groundwater hydraulics.
3/9
JUN-02-98 17:28 FROM,Y.SchulLz 410 ?SB 4404 ID,4107984404 PAGE
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UVB with Labyrinth Air Stripper
UVB-Labyrinth GCW System
The use of the high efficiency labyrinth stripper in combination with the Standard UVB provides
chlorinated voe stripping efficiencies of 98% . The labyrinth stripper is a counter current device providing
large air-to-water ratios and increased residence time. The stripper reactor is located in the vaulted well head
rather than at the capillary fringe as with the Standard UVB. This system is a GZB-like system but with the
technology being all in situ and retains all of the hydrologically self-balancing principles of the UVB. These
units are useful for large, deep, thick plumes and can be placed in series and parallel across the width of such
plumes. The system can be fully automated with sensors and signaling equipment and has a greater than
99% operating efficiency.
4/9
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ID,4107984404 PAGE
Coaxial Groundwater Circulation (CGC) Air Sparging --I
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Coaxial groundwater circulation (CGC) is used in the
remediation of groundwater and of perched water
contaminated with volatile hydrocarbons, but can also
be employed for the injection of gas into the
groundwater for the enhancement of microbiological
degradation. CGC is a method patented by IEG mbH,
Reutlingen, Germany.
CGC consists of a combination of soil air venting with
in sir,, groundwater stripping ("push and pull
rechnique"). Clean compressed air is pumped into a
pressuri2ed air distnbutor located between the capillary
fringe and the aquifer base depending on the vertical
pollu12nt distnbution.
The design of the pressurized air distributor regulates
the air flow so that the air can only flow upward. Toe
air bubbles rise within the well, causing water inside
the well casing to flow upward (air-lift effect)).
Consequently, a continuous circulation of groundwater
is generated in the area surrounding the remediation
well, delivering new contaminants to the stripping
zone. In contrast to other sparging methods, the clean
water leaving the upper screen section of the well has
no air bubbles, therefore, no air-water phases are
produced to impede the flow. In addition, a mass
balance can be obtained between influent and effluent
air.
CGC needs lower pressure, less air volume, and thus
consumes less energy than conventional air sparging
methods. Volatile hydrocarbons dissolved in the
groundwater are transferred from the liquid distribution
coefficient and are extracted from the groundwater
surface via the double-eased screen. Soil air from the
unsaturated zone is also extracted and remediated.
S/9
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GZB -Standard Groundwater Reclrculatlon
GZB Groundwater Circulation Well
The GZB technology provides for the on-site
treatment of withdrawn groundwater and re-
infiltration via the same well. The unit is similar
to the standard UVB but is without the in-well
stripping reactor yet remains a closed-looped
system, avoiding permitting issues. Withdrawn
water is treated for non-volatile or semivolatile
organic or inorganic contaminants using
appropriate treatment technology such a reverse
osmosis, ion exchange or carbon absorption.
Unlike conventional pump and treat approaches
this system maintains the standard UVB
principles of being a self-contained,
hydrologically self-balancing system resulting in
no aquifer draw down or reinjection mounding, a
major design failure of most pump and treat
designs.
Another advantage is the ability of connecting
GZBs in series or parallel installations for large
plume remediation.
Municipal governments and industrial
organizations have recently become interested in
this technology as it effectively lends itself to
applications for improve well water yield,
reduction of iron bacteria, and where mineral
clogging of well screens occurs. It can also be
used as well head protection of sole source
aquifers as it avoids the problem of cross
contamination.
7/9
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PAGE
Soil Air Circular Flow (BL[() Bioventing
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Dirc,;tcd soil Air syst=i> (BLK) arc employed for the
remediation of soil contaminated with volatile
hydrocarbons. In addition, they can be used to inject
gas into the soil for the stimulation of biological or
chemical degradation. Special sa-eens are buih into the
bore hole and are separated into an upper and lower
section, each of which is connected to an above grolllld
negative pressure blower. This allows for the
withdrawal of air from either seg1I1ent individually or
from both simultaneously. The air exrracted, after
passing through a suitable remediation Wlit (i.e.
activated c:arl,on filter), is reinfiltrated into the soil.
Horizontal and vertical flow circulations arc gcnerared
in the soil surroW1ding the extraction well. The
circulation direction is reversible and can be adjusted
according 10· the containment distribution in the soil.
The BLK, in contrast to conventional venting methods,
is capable of generating a directed circulation through
the ~tcr of the conteminatiQn. No fresh o.ir i.s added
to the circulation system. Air passing through the
blower is heated, thereby enhancing desorption of
contaminants adsorbed onto soil particles. This leads to
a more effective remediation of the site.
To stimulare the biological degradation of
contaminants, nutrients. in liquid or gas form, can be
introduced into the circ:ulation. Chemical conversion of
toxic substances into barmless or immobile marerials
can be achieved in situ by introducing, for example,
strongly reactive gases into the soil. If only
biodegradable substances are to be removed from the
subsoil, a BLK system (without an abovegrolllld
eXtraction unit) consisting of an axial ventilator in the
screened well can be implemented.
6/9
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I 12/12/89 4,886,119
-
1/9/90 4,892,688
-
7/24/90 4,943,305 -
: 8/21/90 4,950,394 -
1/13/92 5,116,163 -
1/21/92 5,082,053
-
2/171')'2 5,147,535
-
4/9/92 5,143,607
)/17/92 5,095,975
12/15/92 5,171,104
9/1/92 5,143,606
12/15/92 5,171,103
6/22/93 5,220,958
1/25/94 5,281,333
6n/94 5,318,698
6/21/94 5,322,128
9/13/94 5,345,655
9113/94 5,345,820
9113/94 5,346,330
9/20/94 5,348,420
1110195 S,380, 126
4/4/95 S,403,476
11/21195 5,468,097
mae -U.S. Patenls
i. ( ( ( \. ' .
-

-

-

-

-

-
-I!!!!!!!!! l!!!!!!!:!!I == ;;;;;a liiiii liiiii iiil
UVB TECHNOLOGY -VERTICAL GROUNDWATER CIRCULATION WELL
Soil air vapor extrnclion melhod of and arrangement lo expel volatile impurities from soil
Basic UVB palent -im-angement for expelling lighl volatile conlaminnnts from liquids
UVB for confined aquifer -aerating apparalus for expelling volatile impurities from groundwater
Arrangement lo expel volatile impurilies from groundwater
Sparging -KGB coaxial groundwaler ventilation
Arrangemenl for cleaning conlaminaled groundwater (blo filler and on-site trealmenl)
Expelling impurities from groundwaler using vibration
UVB with slationary aeration pipe
IIVO using various lrcahnenl mclhods/UVB wilh off-gas rwirculalion
OLK soil air circular llow
UVD using various treatment methods
Reverse llow UVB
Arrangement for driving out of volatile impurities from groundwater
Arrangement for cleaning groundwater
Arrangement for cleaning contaminate<! groundwater
Method of forming well regions
Method of and arrangement for obtaining liquids and/or gases from ground or rock layers
Method of and arrangement for determining goo-hydraulic permeability of ground regions through which groundwater llows
Method of yielding oil residues or oil contnining liquids from con laminated ground layeis
Method and arrangement for influencing liquid in ground
Melhod of and arrangement for rinsing out impurities from ground
Arrangement for removing impurilies from groundwater
Method of circulating groundwater in ground regions wilh a fall of groundwater level
111111[ SBP Tuchnologies, Inc. ---. . ......... -·•• ... .
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UVB IN SITU TECHNOLOGY INSTALLATIONS
Date Number of Number of Number of
Locations Installed Sites Systems Closures
EUROPE 1986-1997 144 317 17
UNITED
STATES 1991-1998 47* 69 2
TOTAL I 12 years I 191 386 19
*9 additional in design
---SBP 'lechnologies, Inc.
--Environmen/al Engineers and Bioremedialion Specialist!
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Project Performance Corporation
Exceptional Performance tor Tomorrow's Environment
Project
Performance
IN-WELL VAPOR STRIPPING WITH PRESSURIZED
RECIRCULATING WELL SYSTEMS
The concept of recirculating wells with in-well
vapor stripping was developed and tested in the
late 1980s as an alternative to pump and treat
remedies for volatile organic compound (VOC)
contamination in groundwater. In-well vapor
stripping simplifies the treatment process by
eliminating separate above-ground aqueous
phase treatment.
Project Performance Corporation (PPC) staff
have been involved in the design, installation,
and startup of in-well stripping systems for the
past four years. Under a license agreement for
the patented Density Driven Convection (DOC)
in-well aeration technology, PPC staff can
design, install, and operate advanced systems to
meet your remediation needs.
AJR EXTRACTION
'~
UPPER : : ~ voes
RECHARGE I I iJ}
SCREEN
1 1
-~ WATERT!_,.,A_t:1 B1LE --n ,.,, ~~
/ i~, f~fo ~:!'
t t
STRIPPED
WATER
GROUND WATER RECIRCULATION ZONE)
LOWER INTAKE! I ' A : :
'-SCREEN j 1 / \1 1 VOC-CONTAMINAT ..._.._ 1 1 1 1 WATER / --___..,..,~ ~
Patented In-Well Stripping System
Project Performance Corporation
CX)RP<)RA"l'IC>N
ADVANTAGES OF RECIRCULATING WELL
DESIGNS OVERPUMP AND TREAT
..... SYSTEMS
.. · .. , : ·: ...
t/ Requires Lower Capital and O&M Costs
t/ Reduces Operating Costs, Only Vapors
are Pumped to Surface, Not Water
t/ Eliminates Need for NPDES Permits,
Discharge Fees and Associated
Sampling/Reporting Requirements
t/ Enhances Removal of Chlorinated
Solvents Through Vertical Gradients
and Aggressive Flushing.of the Soil
t/ Enhances Bioremediation of
Hydrocarbons Through Aeration of
Treated Water
t/ Options Available for Recovery of
Separate Phase LNAPLs and DNAPLs
In the DOC system, air is injected via an air line
into the well casing. The air reduces the density
of the water column within the well bore creating
an upward vertical gradient within the wellbore
that draws water in through the lower screen and
pushes aerated groundwater out through the
upper screen. This process creates a
groundwater circulation cell within the aquifer
surrounding the DOC well.
Over 50 full-scale systems have been installed to
date. Cleanup time frame depends on site
geology. Several projects have completed site
remediation in approximately one year. Other
sites in silt and clay formations have achieved
cleanup goals in approximately two years.
Additional information on. in-well vapor
stripping systems is available: by contacting
PPC at the,offites listed below.
64200 E Grover PR NE, West Richland, WA, 99353; Phone [phone]; Fax [phone]
70 Fairway Road., Mesa, WA, 99343; Phone [phone]; Fax [phone]
61330 King Josiah Pl., Bend, OR, 97702; Phone [phone]; Fax [phone]
10035 SE 39th St., Bellevue, WA, 98Cre; Phone [phone]; Fax [phone]
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PROJECT PERFORMANCE CORPORATION
Exceptional Performance for Tomorrow's Environment
531 Elbow Road. Othello, WA 99344 · 509-488-~184 · FAX: [phone]
March 27, 1998
Angela M. Luckie
CDM Federal Programs Corporation
800 Oak Ridge Turnpike, Suite 500
Oak Ridge, TN 37830
Project
i
(0lP0lATI0N
Subject: Recirculating Well Preliminary Design and Budgetary Cost Estimate -North Belmont PCE Superfund Site
Dear Ms. Luckie:
Enclosed as Attachment I please find a budgetary price estimate and preliminary design for the PCE ·superfund Site in North Belmont, Gaston County, North Carolina. The price includes labor for design, well installation oversight, startup and system optimization. The price further includes all well installations (with subsurface vaults), equipment packages (blowers, valving, piping, controllers, switches, etc.,), trailers or buildings to hold equipment, off-gas treatment, pavement cutting, trenching, piping network, covering and resurfacing trenches, and travel and per diem.
We have designed the system to treat the entire plume simultaneously as delineated by Figure 4-9 in the information you provided. The system would comprise 66 in-well stripping wells with seven equipment packages supplying the required air injection and air return. Off-gas treatment would be provided by GAC units placed in series. The system is designed to operate in a closed-loop mode. That is, air coming from the wells containing stripped contaminants would pass through the GAC units for treatment and then be reinjected into the aquifer to continue the air-lift pumping and stripping process.
We have also provided an alternative price for a pilot system. This system would contain one equipment package and operate one recirculating well.
Our preliminary estimate is that each well will pump at a rate of approximately 20 gpm. The actual pumping rate would be determined during well development. The well sizes allow for flexibility in pumping rates and will accommodate higher rates if necessary. This pumping rate would provide a capture width of approximately 240 feet. An air-to-water ratio of 20: I would result in a PCE removal rate of approximately 90 percent for each pass through the well. Accordingly, if the water passed through the well three times, greater than 99.9 percent removal would be attained. The pumping rate of each well would be designed to achieve between 8-10 cycles before allowing the water to escape downgradient thereby ensuring an extremely high removal efficiency.
I
I PROJECT PERFORMANCE CORPORATION Exceptional Performance for Tomorrow's Environment n 531 Elbow Road· Othello, WA 99344 · 509-488-2184 · FAX: [phone]
Project
i
COUOUT!OK D
I We look forward to hearing from you after you have an opportunity to review this proposal. If you have any questions, or desire further information, please call me at 509-488-2184.
I Very truly yours,
I fr-7' J;/4--
Stan R. Peterson, Ph.D. I Senior Program Manager
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E:IFILES\JOBS\CDM\BELMONT.PRO
March 27. 1998
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2.0 Recirculating System Design
The objective of the remediation system is to treat the entire contaminated plume simultaneously.
The system is designed to treat the PCE plume as shown on Figure 4-9. Treating the PCE plume
will remove the other contaminants' plumes as they are in the same area and smaller than the PCE
plume. Seven equipment packages would deliver the air injected into the recirculating wells and
retrieve the air for treatment by GAC units and subsequent reinjection. This closed-loop system
would have no air, treated or otherwise, escaping to ambient air. This is an important
consideration in a populated neighborhood with schools as is found at the Belmont site. Each of
the seven equipment packages would incorporate a small insulated building with two blowers.
Each of the blowers would s_upply air to four or five wells depending on its location within the
plume. The piping network would consist of 4-inch PVC trunk lines with 2-inch laterals feeding
the wells.
The air:water ratio was designed to remove 99.9 percent of the PCE after three treatment cycles
through the well, The treatment cell behaves similarly to a continuously-stirred batch reactor in
chemical engineering. The water in the treatment cell is recycled several times, on average, before
escaping downgradient. The pumping rate of each well would be designed to achieve
approximately 8-10 treatment cycles before allowing the water to escape downgradient.
Therefore, this system is conservatively designed (excess treatment-removal capacity) to help
ensure that regulatory goals are met.
Our preliminary estimate is that each well will pump at a rate of approximately 20 gpm. The
actual pumping rate would be determined during well development. This pumping rate would
provide a capture width of approximately 240 feet.
A pumping rate of roughly 20-25 gpm and an air:water ratio of 15-20 would result in an air flow
of approximately 50 cubic feet per minute (CFM) or a total air flow of approximately 3,300 CFM
for the 66 wells. Each blower would be sized to deliver between approximately 250 CFM.
Depending on the final pumping rates, this may provide enough air to increase the air:watcr ratio
above the preliminary design value of 15-20. Increased air:water ratios result in increased
stripping and pumping efficiencies.
Each well casing would be 8-inch Schedule 80 PVC with an interior eductor pipe of 4-inch
Schedule 40 PVC and a one and one-half inch air injection line. A 12-inch borehole should be
drilled to accommodate the casing and packing materials. Drilling costs are similar to those
required for an extraction well. The major difference in recirculating wells is the installation of a
recharge screen interval in addition to the screen placed at the bottom of the well .. The injection
blower would be sized to handle a startup pressure of 6-7 psi and an operating pressure of
approximately 4-5 psi. The delivery lines will be appropriately sized so that minimal frictional
losses occur.
As you are aware, with this treatment system, no water would be brought to the surface and, in
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the closed-loop mode, no air would exit the system. Accordingly, no above-ground water-
treatment systems, with their attendant water disposal issues, are required which is important in a
populated neighborhood. An additional advantage of this system is its tlexibility. If at some point
in time it is desired to expedite the remediation process, reagents, such as ozone, may be bled into
the airlines to accelerate the remediation process. We have bled ozone into the airline of an
system operating in California with spectacular removal results.
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QUICK-PURGE® IES
QUICK-PURGES is a patented (U.S. Patent No. 5,509,760) remediation method for in-situ
decontamination of soil and groundwater that puts maximum remediation stress on the entire
area and volume of contamination. Groundwater or soil need not be removed from the
subsurface to accomplish remediation. The patented method results in site restoration in days
or weeks as opposed to years. The target contaminants are chlorinated and non-chlorinated
volatile and semi-volatile organic compounds (gasoline, diesel and solvent constituents).
Cleanup concentrations to non-detectable can be achieved when the patented QUICK-PURGES
design is properly implemented. The patented invention uses positive pressure to push an
uncontaminated gas throughout the entire contaminated volume. When contacting the
contaminated media, this gas becomes a carrier gas removing the contaminants and carrying
them to ground level where they can be collected and treated or dissipated to the atmosphere.
The method patent incorporates vertical, horizontal or directional air entry points.
The patented QUICK-PURGES design is also an ideal delivery system for gases and/or liquids
for in-situ destruction of organic compounds or in-situ stabilization of inorganic species.
QUICK-PURGES is currently being used as a delivery system for in-situ ozone destruction of
organic compounds in groundwater. QUICK-PURGES is also being used to deliver nutrients
and oxygen for in-situ bioremediation of groundwater and saturated soil below the water table
and soil above the water table within the capillary fringe and the zone of expanded water table.
QUICK-PURGE® costs are somewhat comparable to the costs for installation and start-up of a
traditional pump and treat/vacuum extraction system. It should be noted that with the more
traditional technologies, unknown years of operation, maintenance, sampling, analyses and
reporting costs are in addition to the installation and start-up costs while the QUICK-PURGES
costs are finite and more easily identified prior to implementation.
A:\MISC2\QPDOC.1
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United States Patent 1191
Schriefer et al.
[541 METHOD OF RAPID PURGING OF
CONTA.WNANTS FROM A CONTAMINATED
AREA OF SOIL OR GROUND WATER
[751 Inw:m.ors: Fral E.. Scllriefu: Robert Bass;
Stq,lml G. Mc:M2llan. all of
Ja<:DOll"lillc. Aa.
[73] A.mgm:c: Inucr:alCd En'l'ironma,tal Solutioas.
[21]
[221
Inc.. Jacksonville. Aa.
Appl. No~ 2:6,991
Filal: Apr. 12, 1994
[Sil Im. a.• ---------F02D 3/00
[521 U.S. a. 405/2Sll: 405/128: 1661245:
1661305.1: 1661310
(58] F"ield oC Seard, 40S/12ll. 129.
40S/258. 52: 1661245. 305.1. 310
(561 w..-Cil.ed
U.S. PAJE?IIT 00CtJMENTS
4,43S.292 3/1984 Km. er. al 210f747
4,&:l2.l22 S/1989 Con,y Cl al. 1661266
,,&Q.448 611989 ICocmcrc<al. = 5.Dll.329 411991 NdsmClai. 405ll2ll
5.IIIZ.ll42 7n991 Sd!m,q Cl al. 405/258
SJ116.TZ1 12/1991 l-Clai. 405ll2ll
5.161.914 11/1992 Ra!m Cl al. 40Y1lll
5.171.491 1/1993 Cira.es Cl al 405ll28
5.193.934 3/1993 Jotmsoc Cl al -'051128
.5.Zll.1.59 611993 llilliD15 Cl al. 405/128
5.246.309 9/1993 I!--, -'051128
5.249.188 10/1993 -Clai. -'0511:?ll
5.:!Sl.700 10/1993 NasoG Cl :al. 166/305.1
5.263.795 11/1993 Con,y Cl al. 405/128
5.277.518 1/1994 8~ Cl al. 40Sf12S
5.288.169 211994 Ncc!'Cl' =
A)REIGN PAlEl'IT DOCUMENTS
3601490 7n987 Gcnmmy 405/128
I lllll rntlEI Ill 11111 IEE fflE 1M lllll llill lllll lllll llllll Ill lllll llll
US005509760A
1111 Patent Number:
[451 Date of Patent:
Primary E,an,i,,,,r-lobn A. Ricci
5,509,760
Apr. 23, 1996
,-\aa,,,.,. Ag-. or Fimt-Sugmuc. Mion. Zinn. Macpc:1k &
Sc:is
[57] ABSl'RACT
A remediation cn:emod far dcn:Rnanrin:nion o( soil md
paumiwW::r tml pua maximum n:mcdialion sm:ss on the
cm:in:: 3ZC1 and votwnc of mmmrinarion. Titi.s n::suia in site
rammion in days and wms. The ~ C"fltarninanrs arc
orpmc CQ!lllJ(l"rnds mdl as bydzOCJlboJ CDOS1in1cn1s uso-
ciar<d wiLII diad fuel. gasoline. kamcnc. solvcms and
aaJICXC. Qamq, cw:ca:u:.a:iam to oon...Ae1ecn:h1c levels
cm be a:mc-...1 when prup,::riy imi,lcmenu:d. Positive pn,s-
sun: is used. CD push m nnamADrinatni gas duougbout U1C
cnmc c:nru•~ ~umc. = comaamg the coo-
tmri:rmcd 3ICL YOium:e md media. this gas becuu1es 3
c::aaier gas. smpping ur awarninams and can,ing tbem w
gmmd level where thc-f cm be a,ilca:d and in:a=1 or
ctissiptcd to tbc II \ j 1<" .. The method ~ air
t:11lrf poims (Yfflical. llo<i20utai. ar direaioaal) inswJed IO
a dl:pd1 below die corn:amiaatim combined wu.b a prcdc-
lamiDed air t:11lrf poim ~ (dc;xll/"'8C"g ratio). Use
of m opcr.v.ing duly cyde cnhmcc:s comarnimmt yield from
Iba g,oumiw:ua. dlC soil nmrix below the grow,dwau:r
tmle. and the soil above dlC gnxmdwaJa table. Hmizom:11
migrmion of cmmnirnum during tbc process is prevenu:d
by die DSC Oi gas t:11lrf poims :uound a bounda,y pcrim=r
of die mac being pmg,::d. One or ""° day>' use of :he
mcdmd p!t>duccs dlC same rcsuils JS OIIC v= of otllcr
'M!P'dia«ioo mo bods sudi a.s iMD? and rrr:::u.". Transfer or
relllDftl r.u.cs oi .IO'l, to 51)'11, per day oi the existing
awa::arin:ams arc normal .So (vacuum) c:nraaion wdl5 arc
m:a:ssary to awe,: this in-sim method wort Biodegr.l.dalion
is aot a facer.. ~ is measwc:i by the :unount of
r oioanrs n:maimng. Sile rchamlit:w.on to rcguiawry
staDdmis.. mc:JSUff:d in miaograms per liter or parts per
billion. = be xllicved witbin W<Ciu.
30 Oaims. 9 Dnwia,: Sbm,
GROUND AIR ENTRY REMEDIATION AIR ENTRY
_su,--RF._Ac._E_,_ ____ P0_1_NT-;)1-,-__,STR,.....;c..ES_s.,,._AR_E-1:A--.,fi-PO-•_NT ______ -;-
',, ', ( // ///
WATER ', /
TABLE ', /
/
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m n n 0 D D E I • I -1--.. I I I I I I I I 5.509.760 1 METHOD OF RAPID PURGING OF CONTAMJNAJ'ITS FROM A CONTAMINATED ARE.A OF SOIL OR GROUND WATER 2 rncsc methods cul on lhcir scicacd JrC:1S is wdl below t.he lcvei of rcmo:iia1ion sues or imcnsity produced by our iavcmioa.. A known ··Jetivc·· remediation procc:ss is soil cxcvation. BACKGROUND OF TI-IE JNVENTION S Alt.bough this pnx:a,s is mcccssiu1 on soil ;ibove !.he wau:r , table.. it has sig:oilicant rcmcdim:ion limiwions on soil or gruundw3la in thc underlying aquifer. lf soil bctow tile waa:r Clb!e is removed.. rema::iain:g cao,arn,·narcd grouodwa-ta-in tbc aqui£cr will n::..rrmramimrc the backtill bciow the The prcscm invcmirm rcllrles primarily 10 methods use ia sim-n:ilabilirarion cifons of grarmd W1W:I" .md/or soil con-ranrinucd wilh orpaic compounds such a1 hydrt,cubou cmz,rinrnus asVW,ared with diesel fucL gasoline.. kcroscJe. sol...,..audcn:osoce.. to wmrr Clble. tben:by rcswm,g in thc =lion of additional • iiiilllhtit No1 wil.. At me pn:scm t:imc. site .'CDCCDarirn, for byda.w.::ubo:u comriorrnrs r.akc, ym and dccadcs.. The most widdy used aquifer ...,,..,.i,riM rcdmology is lcaown as "pump and acae. This comiJls of cma.tiog (pum¢ng) grouudwau:r " !mm recovery wdi(s). and pwzq,iDg it ID m ~ tn:llmCnt sysu:m. rcmo~ tbe rornanriaaru, from the cma::u::d groumiwau:z:. md rc..lnrllttating the aow uncon. rzmim•cd gn,w,dwm.cr back ID die aquifer or disclzorg;ng 10 a sumcc ....r"1" body. This method has bad ;in cm,:mdy lll poor sua:css r.w: and is mn-p,ojcat:d by the EPA lO <ala, 30 y<:m:1 of opcr.uioa per siu: ID acltiae lllrg,:t levels. This IIIClllocl also bas pr0"C1 ID be iocfficicm and oat COSt dl"mivc. Due ID the red soil matrix below the ---table. the dufusion of • ..,, II from the soil " 1bD puhtisbcd prior an docs aot p:rcscm cffic:icm ~ dream, mes.bods ID adlicYC typic:11 Fedc'3I :md Sow: sue rnrmrion s:rmda:nis i.n a short period of time. particuiariy wbm oaua · n:t gmuudwma is involved. For c:xarnvte u.s." P3L No. 5.221.159 (Billings ct 31) requires vacuum cunnim in coajunaion with ox~g~ air injcaion. plus aawral aDd m.,_ bi~oo. This paa:m. spc:c:ifinUy irx#arn • mwmcc solely on bi~· dalioa ID address dicsr' comritttcntS md ilia SJ)CCttcally rm mat site zrnr:djatjon time is mc:mzn:d in u:rms of ycm:::s,. tbcreby md:icziug ma,r m:acr:iannn rcmcmarioa Stt'CSS is DO( adlicval. U.S. Plll.. No. 5.277.518 (Billings ct 31). ~ ~ discloses a Y<Dlmg/colleaion sysiem for air cmissiam. 311d requires a Vall wcil within 200 fee< on aamx ID the groum;,nl'""QJIIDOIIOIJSly rc-couwmnates the an air t:mrf point. Bodi of llll:sc pau:ms CID be considered grouodwau:r. tllc<cby rcsutmg in siu:-1iwion cd"ons ':' ,. bemg di=icd ID passi..: ICdmiqucs. _ _ be mi:asumi in dec:idcs. The pttDl!I and trc:11 lllC!ilod S U.S. Plll.. No. 4.435.292 (!Gd;.) rcquirc:s simulWlCOUS ;ur dcmmp times arc dcF>doot ""aquifer pcnocability. :md on 30 iDjeCliaa am! c-=:iwioa in a dosed loop sys,cm for mass lllllm:lli dilfusioa r.w:s from die soil IDOlm ID the pore wao:r. mfl:r of th,, rnd . I 111 ••> the cmicr P,.. Emaaim, vta and dJis mi:1hoc1 dac:s OOL addrm die soil cnnarnimtion m:pli..: prc:ssun:: (vacmmi poimsl is critical ID tl>is mcslloci. abcm: the wucr t3lllc. Rcmrdiarirm sm:ss on die =· U.S. Plll.. No. 4.842.448 (!Coc:r=J uses gos injeaion and 11111m an::i dissipascs dasuclliy w,th distance from the iu for=! c:xmaion from the soiL but n:quircs i~lc n:<:O>ery wcil. l5 boti:zumal am! vc,ticll bamc,s arow,d the contamullllCd Anadlcr ;,ouul2t mt:alOd. oflcn used sq,,,mdy or in 3ICL This lllClhod is based on pres= reduction (vacwml amjunction with "\JUlDII and trcar". is soil vacuum ex=-IO dmw OUl the cmicr g;,s. lion. This method cormm oi cx.a:,a;.,g subsum= vapon U.S. Pal. No. 4.832.122 (u,rcy et :Ill uses in-siw gu from the soil abcne die W1W:I" table .""' a vacuum pwm,. injection and vacuum cxu=ion ro add=s volaul_e coruami-H.,.,.,..,,.. this =on srcp bas little or no elfcct on ..,, nams in grow,dwa= This mcdmd rcquirc:s sigmnc:,m ncga-ranrcUatin~ :my assanared groundwaicr. Further. 11. LS · w: p:rcssureivaamm to draw the injeacd gas :icross UlC dq,cndenr on the oamral soil dill'usiou ra= for rdCISlllg ~n•red groundwau:r. U.S Pot. No. 5.263. 795 (Corey crmtaminaurs from ~-soil ID the air in_ the _pore sl'."""-ct al);, ..owcwhat of au cxu:miou of the ·122 pau:n< bU[ Remr:diarica mess ctissqmr, dnsnnfly wtth di.stance ttom addresxs mcmi cmamrimrifJD. rdics on bio-dcgr.ldation. tba vapor aaaaioa poim. 4!1 and arm cnmmrirnrms iD-sim withoul n:mova.l.. In-cw biociegr:,dalian of soil and g,oundwau:r i.s • ~-U.S. Pal. No. 5.076.m (Jobmon ct :Ill describes• dosed diaziao rcdmiqu.c llm_ bas gaim,d aucmioo but bas lw1 little loop sysu:m of injcctioo and ..-uum withdr.l,nl. designed <r 00 sua:cu ID acmc,,;,,g dc:mmp targcl staDdards. This ID -the soil with miauwa..:s. thcn:by c:wssog rcic:ise of mcdlDd is a "livesmu. rmmriug"' app,oacb tlllll umoduccs noa-.olmilc bymocubou amtaurimo•-.. The parcot swcs bam:ria (otiao--<>rplDSUIS) or entmrrs the oaniraUy occur-lO tlm ocgalivc prcuun: (VllCUWII) is nccdcd ID wilhdr.,w the ring baacria to em or brcsk down the ama,rnnarns For v..,ars. and n:qaircs 311 impameablc surfac:c. U.S. P3L No. iJ>-um conditions. Ibis is a very slow proa:ss and bas had 5_193.934 (Jolmson ct all also describes a process dcsi~cd Imle or no = in adlieYmg nonoa.l rcguwmy clcmup IO bcm. the soil and vaporize the h1moc.abons. but this target levels. partia1lany in the miaogram1)C'•htc:r or pans-w:moo imct3 bot combostioo ptOduas inlO soil under per-billion range. It is ilia questionable 3S ID how _much l5 -ocplivc pressure c:ooditions in a dosed loop sysu:m with 3D rcmn:fiation suess this mz:ibod ~ to the cmtamma~ed . me.able suriac:. an:a. particularly after the initial rnntarnimor com:cmr.rnon "":T.s. P3L No. 5.032.ll42 (Shuring ct all describes a n:duaion. fracairing ieamiquc to csmblish prcicrcnrial flow cilanneis ~ the soil ai,o,,c the wau:r table to cnnana: ,-=um cmwiou or air iujcctioo. U.S. P3L No. 5.249.888 (Br>irhwaiiel relics on crc:uing ncgau..: pressure (YaCWml in the subsw-t:u:c :md docs no, n:qqi,c air injeaino. Bc=ri.-lire pmtll' and rrcu. sail vacuum cxtr.leion. :md in-situ biodegr:,datiaa WCll>ods m: c:xtt=cly slow pro-60 a,sacs that dcpemi rm subsurface coodirioas or yidds. :md n:qqi,c ye:rn of imi,lcmcmarim at the sire. they c:rn be comidcrcd as -passi..:" n:nntiarion mctbods. TI=e mcth· ods apply their maxinnun remedialioa suess to small. scle:tcd ponions oi the contaznim<cd ==i. :md liuJc or no n:med.iation s~ to the larger pc:n:c:n~ oi the concuni-nau::d lrC:L Funhermorc. r.bl: :unoum ot remediation sm:ss o, U.S. P3L No. 5.246.309 (Hobb)' l discloses a dosed loop system Ul3l reties on negative subsu:ri:u:c pressure to dr:Jw :ind fmf'Olialc vapors through lnc cont.iminau:d J,tC:L. The
m m D u D I I I I I I I I I I I I I I 5.509,760 3 coru.uninants in the va;,ors ari: uc:uai Cy the biodc~on effects from micro-o~anisms in lh.e subsurface :md .:i surface bio-n::aaor. U.S. P:lt. No. 5..251.iOO (NcisooJ is a mCUtOd and device far injecting hot gas under :m impc:rmca.t,lc surf3CC and into l the subsurt:u:c using ,pccially ad:q,tcd wellbon: outlets -oriCll the ho< vapor, injcaa! imD the soil from a well bore, ill a pn,-dclormim:d or comroilcd well bon: exiling paacn. This mcdJod n:quircs dcwmcrmg or n:monl of m:c dowing --=r in tt1c soil area or volume of soil prior to n:mcdialion. 10 SUMMARY OF 'THE INVENTION 4 mau:ly 20 ft. ecr day. ,wo cycles per day have n:sul~ in 65 % 10 75 % con"11ninant n:duaionlremoval per c:llauiar day. Lowe!' pcrme:,trilities_ such >s 0.5 ft. per day. n:qwn: longer slnlldown periods. illen:by limiting operations to one oper-JU.Dg cydc per day. A conrinuous opc::r.uing cycle with no slnlldown = also be pc:n'ormai. although bcaa rculu havc bcca achieved with a shu<down period. Allother objea of Ibis invention i3 simuJIJlaeausly 10 n:movc crmrarninanrs from soil and groundwater with the same Clfon_ Anotbc:r objca of this invcmion is to n:move comami• ama from the soil awrix below the wmcr <able. !f the soil cmaix below the water table is not free of comarninanrs it cm comimJc to di!fusclleac:b its amtamiamu imo tnc Jj gruundwa1l:r prescm in the adjaa:m pcm: spa:,:. In a short period of time.. this. will cnmamiaarc rc<:ootaminvrc or cmmibwc to amramiaanr Jcvds in me groundwatcc. Our invemiaa mnectiarc, IIydroc:ilt:w:JU Q"tTUaminarcd soil and/or gn,uadwmcr wi<llin sc>enJ days or """4 bccwse the invention has li<lle or an depmdcm:e na aaauaily oa:mring subsurface limiwiam. l1 i3 the only "aaivc" in-sin, dccomamiaation process al the pn:scm time tlla.t n-awti3'M •oil mrJ/or grouadwau:r. il also U the only n-awtiarion proa:ss u Ibis lime tlm can simal-.Jy lD apply marirm,m 'T't"cdiatina srrm dzmaghour. the cmin: c:mn::cnimred m:a/votume. · Another obj ca of this in'Vl:Dtion .is to climinarc ill' n:ducc cumauaion cxpemc of burying !low lines and fcedc-lines. Sina: the rcmcdiaaoa oa:m-s so ai,idly, the requin:d surface equipmem cm be tcmµwm 1 and portable. irrinding ,,cm. paary abovc~ lines. boscs and piping. Another "1-nmagc of Ibis um:mion i3 tlm it cm rchabiliWc peuo-icmKmitamimtcd siics in days and wecb. .. opposed 10 The um:mioa uses posilivc pn:ssme 10 push a gas tbroughou.t the emu,-mmarninved "IICZ. voiume.. 3Dd media. By puslliag the gm. Illllla llml relying on drawing or (VKZIWD) em:,aioa. ail pans of UII.· Cililli red 1IJCl CIQ be simul<=usiy rcoc!J,:d 10 pnmdc anximum mnn1iarinn sm:ss. even witb a1hsnrfac:e pmncotriHry dilfe:n:::aa:s. Also o,i years and dCCldcs. CSlJl'Clllly oy the use of compr=sed gas (e.g.. comp=scd air). by pasltiag with politivc pressmc. the iafu1mcr nf subsur-faa: baar.s sudi as pcm,:alrility dilfaciccs and odzr siu: JO noo-bumogc:ncom dranncrisrin "2D become i.css i.mponam «c:YeDincomcqucmiaLAgasucha, ◄fTl ~io:ui.::tir(809& aiuogea. 20% oxyzcn) can used bcc:ime it i3 l'C!dily avail-able. However. o<hcr gasn could be used. Thus. ,1 first object of our invcm:ioa is to apply maxianrm n:mr:diarion s~ to the em:in: comarnimred 1rC3.. volume and media by using a~ de;,tll and~ ruio Jj nf the air cmry poims. 1n •=rinM uaamsoiidau:d soiu -aquifers. we have found dJa[ the emered gas will rise ,. from the air emry poial owlet, through the aquifer. and thraagh the soil abovc the wau:r table. 10 growxl level. and will eaa,mpass 3l'P'DJtimalely a 45 deg,= mgle from ¥efficaJ.. Thcn:.iorc. the plan view radius oi intlncno: is the samo as the de;,tll of the air cmry poial owlet, Cross-,, sa::rime!ly. the cm:ire area/volume bclwem venial and me 45 degree angic will ra::cive maximum 'ffl'.ICriiarion mess. The an:a below <his aaglclpalb will noc: rccci-n: rcm:diation ....,.._ The arc, below Ibis pull i3 n:tcrrcd 10 u the "dcul Amxhcr objcc of this invcmion i.1 w climinarc the need [er n:moval of grouadwau:r or soil <o :u:compli.sb siu: ""fflltrlitation. Another objea nf Ibis illveatioa i3 10 rC!d! many regu• lamry rcmcdiaaon targ,:t lcvas whicl! an: measured in miaograms-pcr-liter or pans-per-billion. These reguia[ory targ,:t lcvas havc oitca bcca cuasidac:I impossible 10 acmcve and maimain. Another ad~e oi <his invcmioa i3 tlla.t i< aall3lly has been implemearcd. Jad bas ~y ralw:cd caawninan< couccmratioas 10 I miaograms-pcr-liu:r (paru-per-billionJ, and less. in >bort time iramcs. Thus. conwniaam n:duaionl removal raICS arc mx p:mjc:c:tiam or spcawu:ions. Aaolbcr objea oi Ibis invcmioa i3 10 reduce the mc:ui-iug{ulaeu of subsurf.la: variables_ as implemcuarion of the ilm:m:ion fOCUSC3 on cornmrioam dcptb as lbe primary eam:iderarion. Its "'active" ~ oven:omc:s obsaclcs tha1 an:: m-jor cuasidc:aions wbm using prior art "passive" l<dmiqw:s. Aao<bcr advamage of Ibis iavcmioa i3 dJa< 3Wlic:ition of oegmivc pn:ssm,: to me subsuria0: via vacuum a.tr.11:tion is m:ilher aecnsary nor retied upon. 2IIIDII ". The point al whicb air mcum from ,djaa:at oir ,o Another advamagc of <his ioveatioa ;, tha1 i< docs not cmry paims co-mingle i3 called the iutc.iacua. ,x,im(s). To rcqaile an ""1>amc,!,ie surface.. .,,,,.,,,H,b marirnnrn rcmatiar:ion Sll'CSI tb:raogbom the em:ire com:aminated m::1. volume. 3Dd media. proper air Another advamagc of Ibis iavemioa i3 that. i, docs no, imply or rely on biodegra,1aa:oa eifeas. cmry paiau depth and •l'ICilg can be designed 10 cwsc the . . . . . . • . uWetfaUlQ. p0iat10 be at or below thecnmamiaafioa depth. Allotheradvamagc of Ibis mvcauoa IS tha1 tt IS an :u:ave = ., ... __ ,, . . __ . f .• l$ ram:di.arion method •. l1 <aJa:s comm! nf the subsurt'acc :u ..., _ ••-air cmry pomlS al = pcnmeo:r O we . ff • · l1 docs n:I otha-· ,,_....., .... ...,.,·03...,,cd,.. area with me same spacing and depth r.uio. ~ to 1n nmnng tL. DOlnf y ~ m --~ s 1bm. during oocrmon. then: will be a=cd a subsurface yidd or OHillnily ~ rues u:msrcr or ~gc. bydnlulic OOWldary ;m,vcntiag 'lomom:iily OUlwart1 CQQ• mnirzmu migr:ujon and aidinlJ in m apparent ~tosioa of 60-the amiamirwa! arc, and volume. ADlxhc:r t"c:uun: of invention is the use of a dmy cycle. For cxamplc. opa:uiag for four to fivc hours. followed oy an 8 ta 16 hour shutdown period to 3J.low 5tal:ic conditions to rcmm and allow any inducm prcicrcmial pau,--,s 10 hc::11. •> has resulted in i.10 to 50% conwninam removal r.w::s per oper.uing cycle. (n pcrme:lbilitio ~ :.tun ~xi-Amd1cr :u:tvan~ oi this invention is th:n it pws maxi-mum n:mt:tliaiioa sucss ~= the cmirc: conwntn:uai = simultaneously. Amxher ad~ of this iaw:mion is that it en use l<::tdily available :waosphcric :w: lo addition to our invention's use in soil (unconsotid:w:d sediments) and unconrlncd .fer. it c:m aiso be ~tied lO amsolidau:d sediments lbcd. rod:) md. conrincd ;ind scmi-conrined :iquiicr.
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5.509,760
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BRIEF DESCRIPTION OF TilE DRAWINGS be air cmry poirus with Lhc same de?UJ. to spacing relation•
ship instal.Jc:d l1 or ow.side tbc conwninant boundary to
FlG. 1 i.s c:ross--scctiona1 view of the subsurface siuwion JSSmC 00 horizontal conwnimnt rnigr.:llion. The same
during ope:r.uion with n:spc:a to the vcrtic::i.l ex.tell of design par.mu:tc:n c::m be used with horizontal Jir entry
coatarninarion. It shows the 3I'Cl undagoin~ rc:mcciia1ioa ~ poims illustrar.cd in AG . ..i. am1 witb the direaion:ai Jir entry
sm:sa. and the m:a not =ciYU1g mncdi3WlD sacss (dcld poims illusumcd in FIG. S.
mac). 'Ibis figw,: also showa l!lc opcruioa using vcnic1I air ,., simarions wbi:re the aquifer and soil above the aquifer
c:mzy poims. aurl '"DlCdi•riml oi: groundw1llcr. soil awrix bach C0lllaiD mnramin=• •'>c aquifer sbauld be the primary
wimiD lha gn,undwma .rcr. and soil abcM: l!lc -= rasga: for=crli•tion The ga, (air) mo,,cs upward imougb
table. It also -Iha inu:rfczena: point locau:d below the lO the aquifer and tllrougii the soil zone abo.., the W8ICr table.
~ mmamination. also addn:ssing tbr mmamimviD"I in the soil zone :IS well as
FIGS. l and J an: plan views sbowing Iha locmon of the amnmsin•tion in 1!1c aquifer:
air c:mzy poims wilb rapea 10 the bmimmal cnmt oi lforiznnra! •od/ordin:ainmily drillcdaircmry points c:m
cmltlllm· 1111mci,an. They also show •~ a l1llDIOC' oi air also be used. FIG. 4 rcprac:ms the ams-scaional view of
c:mzy paims at the edge or auaidc the !Xlli.wmal bouDdary ., Lile ..ca being =cdiarcd "'ling llorizomal air emry poims.
r,f cmmrminatioa "' a,sm,: p,ew:mion of my outWml coa-and AG. 5 using din:cirmal (indinc:d bctw=n the vcnic:11
. I angtlllian during !be opermimL and tb. bmiwmal) air t:mr/ poims.
FIG. 4 is an CUID!Jic of using llorizooral air cmry poims. Use of a dmy cyde for rcimvai and smw:town period for
flO. S is like flGS.. 1 md 4. but sbowing din::a::immily xr,mmlarionlcquilibria puq,osa CT!bam:c, CMJatmnanr
dzillai c:mzy wells. 20 rcmDftl. FIG. 6 d.cnxla"'1IICS this by showing cmpiru;al
FIG. 0 show, this um:mion's ~ =muilJfflt n::sulls from this inv<mioa's c:ac hisu>rics oa groundwiucr.
· !e,s fargmundwmcrmpn:dia~timcm:edcd FIG. 7 isac:ac llisuJry of mnmniaanl ramaion r.ucs in soil
IO res:!, n:mcdiation -mncemrziam. The presema1 at,o,,e the W31Cf table as mctsm'Cd by ao ~ Vapor cma an: &om aam1 ,;,.,. in Florida. Aaalyn:r wilb a Flame loaization D«= Nau: tll31 50%
2' rc:duaion of the rcmining mru:aminana per dUly cycle is
FIG. 7 is 3lJP!ic!b!e m soils. It is from m .aua1 site in ammal for groum1wm:r and/ar ,ail_ If the site· s pcnneolrili<y
F1arida wbe,,-mo ·,cacn ••xluaioa in soil ab<m: the-= is apprm:imarelr 20 ft. per day or g,:=. "'° cycles per day
table -cm:asumi Two 4 hour dmy cydes per day may be po,sible (wilb ~y S hours smndown
•q I by 8 hour=< periods wac pcuinwa!. It Im the period in between) resulting in ·up 10 75 ,;r, n:dw:lion/
same · f rrmmai rm as gmundwatcr. 30 n:man1 of corraminarioo p:r c:tlcmiaz-day.
FIG. 8 is a schematic~ ,J)nvraring appm:aws for Compressed ar I h ricairis me:~cm:rygasduc
irrq,I · g the d · 1 IZ'd proa,:ss illumzed in 10 il3 a.bundanr •"2ilabilit'f aod low msr. How,:w:i-. olbcr
FIGS. l-7. gasea. sudr a, aiaogm aod c:arboa dioxide. muld be used.
FIGS. 9 and 10 an: ams-scaional view, of cypical In the .....;cm:,< em,-,r 1 .u ..-;_ oi the cnrin: ...acal air -well cousrruaiom. ... -~---, 15 mnmnimred 1rC1. bcc.b vcn:ic:aJ.ly md borimmaily. sirm.lJ..
PREFERRED EMBODIMENTS OF 1liE
INVENTION
The following descriJ,tiom of !be pn:icm:r' cmbodi1DCT11s '"
are cxr:mptary in aawn: aod an: cot inl.cDdcd 10 limit the
ilr,c:minu' s scope. use ar ,pplicabilit'f.
Aa:ording to the prcfam:i cmMdirnmt of mis inYeDtion.
it i,, disdmed •hat fon:z:d air emry inm the sumuriace via
amlriV,c ur cmry points oa:ms.. It is funner disclosed um ,.,
die tixcod air emry silould -nmmally be sabjccrcd tD my
pt e limiwions. Apprmimar.cly 10 m 50 cubic fccr per
mimlll: (cfm) peremry poimhas been normally pn:imui but
--tD these ..,,um:,. As ClltCff:d air is fon:cd 10 the
smface. i1 capmrc, (strips) and c:mib , iillillllill•iil• from ,o
!be gxoundwau:r. Cl!JtD'CI (,mp,) and came, c,,111a111i11Hllh
Cram Ille soil maaix below the grow:clwm..r table. and
c:apuACS (sui-ps) and cmies cornamina:an from the soil
-Ille Waler table.
Rt:ti:mrrg m FIG. 1. and dea:rmining a 111ui1 llll .. ,n. '5
lllmirmrtl deplb below ground surf= of 11 feet. the inter-== point bctw=n air sm:ams should be 00 shallower
tllBt 11 feet below land sumcc. To cswilisll the ;..u,ruCDLL
paim at 11 ft bciow ground lc-.e!. vcmal air emry poims
widl l.S m 5 ft of sc:n:cu (oarleU on boaom. c:m be inmlled 60
18 r..:t deep and 18 ft aparL ~ .,,.., 10 cmbtisb the
imaiu= poinrar JI fccr below ground !cvcL mu!d be 10
imtall VCUC1I air cmry poims 10 a dcptb of 24 fccr si=:m
26 feet -patt. Other mmlrinations an: also possible. so !Dilg
a Ille ou11eaing air's rise c,..,-run of I ft oi rise per I ft of OS
nm (45 ~ anglcl is used in the :,ir crut'/ point daM 10
spacing design. Also. n:fcmng to FIGS. 2 :ind J. <lien: c:in
t3DCDUS.ly recci.ve maximurn '"7'.IC'diarion mess.
If air cmissiom at the surface cx.a:cd rquia1ory standanis..
the emissions cm be capmmi m,jjor ttr::ltCd via variom
lbc range of air cnay flow ralCS 31 mos1. sicc:s nccdcd to
_ accomplish op<imum subsun'acc mass iransicr of conrami-
aams i, typically between 0.04 and 0.1 cubic fca per minute
per ~ foal of cadl air emry point's m:a of mvcragc.
wilb 0.08 cfmlsq ft appearing 10 be :m ail IJUl1)0SC design.
1bc meal m>aagc for cadl air cmry point cm be 3lllffllxi-
maa:d by fil1l dclcrmining ti,. bociwmal diswla: from each
emry point 10 its adjaccn1 imcfam ,.nnrs. In FIG. 1 tbis
would be 9 fca. Cn:aling a~ :rround Ibis air UUIY point
would n:,uJr in ao arc,, oi (9+91 times (9+9) or 324 square
feet. This m:a mulriplicd by 0.04 cfmlsq ft 10 0.1 cim/sq ft.
n:su!Js in an air cm:ry rate design far the :tir ClllIY point of 13
cfm tD 32 cfm. Ano<IJ-estimation ni an:al m-=ge in FIG.
1 is m u,c: a ciJCrlar paaan aruuod !be air emry point wilb
a radius of 9 fca. =iltir,g in ao areas oi (9x9x3.14) or 254
square fca. This an:a mwtiplicd by 0.04 cim/sq. ft. [O 0, J
din/sq. ft. =ilts in ao air Ull1"f r.irc design for the air amy
point of 10 cfm 10 25 cfm. 1bc Clfccrivcm:ss of lower air
may rmc., may become more suscc::mbfc to the indUCICl:S of
a sire's pcrmc:,bilit'/ V1lrialinas. Higi,cr air emry r:ucs =
lcu Ptsa:;,ihlc. Toe use of gr=cr !ban 0.1 cl'misq. ft or
even wgc amounrs of ovcmll does mx appc:,r 10 do harm
to the mass a.mstC' process and provides ;issur;mccs um
rnvinmrn conwnim:m. n:moni ratc:S an: occurring.
Th<rc is some lictd cvidcna: indic:Jlin~ tll31 l..-gc :unounts
of oYCririlL mcning incrctSing t.hc: ctm per :Ur emry point.
cm incn:::isc the Jngtc to the inu:rtcrcna:: poinusJ. This
I I g n n D E m I I I I I I I I I I I 5.509,760 7 would Cl.USC I.he intcrtc:c:Ice point(s) to occur dcepc:r. The borimncaJ. disuncc from the J.ir entry poim t0 r.hc intcricr-cnc: poinUs) wouid still n:main the same. In Ille pr,:fc:m:d cmoodimcn~ comp=scd air is used 10 acbicve the desired :iir flow r.u.e to obtain striwi,ng of the s amcmrinants. We have used Ingersoll Rand cornpn::ss,oo nw:d from 100 O'M 10 750 O'M at 100 PSL '111d an Atlas Copco c:ompn:ssor r.11ai 31 llOO CFM/100 PSL Where ~ a blower c:m be used 10 supply the=. if it bas , snfficimt PSI rating. The use of compressed. air in the 10 pn:{c:m:d embodiment is a very imJ)Ott3l1I fc::iwn: of our ilm,ntion. and we have dlasclJ air cornpn::ss,oo whose PSI namg is more U13D =¢ 10 prod=: a llow r:lle (cfm) mfflricm •a acaJffll'lisll the mgn speed saipping md ~g -provide Ille= :idvamagcs and •rnn..-acd -lj ofourinve:mion. While we have described one or more p,efcm:d embodi-mam of our invcm:ion. it sbouid be undcmood tllar: obviou, -tllcrcof arc within the SC01"' of the in=noa wmdt is limw:d oaly as denned by the following daims. lD Wlmisdaimaiis: L A method of rapid purgjng of rnntmrinaan from a 8 9. The method as de.tined in claim a. wherein said surface of the c:inn :-t:mains a posed to the c:irth · s J.anosohc:rc throughout the performance of said steps. · 10. The mabad as de!mc,:i in cl.aim 9. whercia said level is eamely bcm:alll said comaminated zone. IL The method as dcsi=:i in cl.aim 10. wlu:n:in the matamirrants arc SU'ilJpcd from said soil or water wicbow. bea:rmg the a"'Dtamirnmr, 12. The mcmod as dcm!cd iu cl.aim IL wlu:n:in said com:arninanr, are purged from said comarninarcd zone only by saipping. via said z uamicr. 3D.d without biodcgra~ dari.an oi the cooamimrns 13. The metllod as ddmcd in claim 4. wben:in said forcing su:;, comi,nses fon:mg l gas uad.er positive pn:ssurc iam said two "°"' boles. md when:in said gu dows upwazdly, W1UIDUI ,;,pticatiaa of any vaaium or negmive pn:ssmc. lioag said patlls 10 said sun'acc. 14. The me1llod as dcm!cd in cl.aim J. wben::in said fon:mg su:;, annpriscs forcing a gas uad.er positive pn:ssurc into said two ban: boles. and whcn:in said gas 80... upwazdly. "'1UIDUl .q,pliatial of any VIClWll or acgmive pn:ssmc. lioag said patlls 10 said smia= 15. The metllod as delina! in claim J. whcn:in said gas is aanosphcric 3ir. 16. The lll<lhDd as ddmcd in cl.aim 2. furtber comprising forming said two ban: holes so tlm they exu:nd borimm.ally bcm::am. said Will !-:d ZDDC. • >N01111ioarcd zone oi sail or ground water which is lo::ucd bcm:::mh a. suma: of tbc cmn.. said amtmrimmn including hydzocatbou mnsriruma assoriara1 with dicsci fud. gaso.. ~ lim:. kaoscnc. solvean and crcosore. said mcmod anni,ris-u,g tbe s:eps of: 17. The method as ddim:d in claim 16. wlu:n:in said forcing step c:om!Jrises fo,mg a gas uad.er positive pn:ssurc inm said two ban: bot.es. md when:in said gas dows JO "lJW'l'diy, without appticmoa of any vaaium or acgmive prc:smn:. along said paths ID said sumo:. fonniJ1g at least two bore boles exu:uding 31 a dept.ll beacatl, said zoae: Corcing a gu imo said two bore boles and imo said anmriaarcd "'°" so tlm said gas exits said bore holes and 8ow, alaag parJ,s "lJW'l'diy from said bore boles 10 said suriaa: in volumes ead1 baviag a sllapc appmlti-lllllll:ly that of aa ilm:ni:d coae having (I) a = 31 3, a ~t poniaa of =n bore hole :md (2) a amic.l suriacc of revoJwion about .m axis: sparing said two bore holes apan by a prcdeo::rmincd discmcc sud! tlm the amicli surfaces ini=ea at aa inu:tfum point tlm is at a levd whidl is at or .ao bencm.h said amrnrn:imrn1 zonc to be purged: am:1 sdening , range of gas flow r.w:s for the gas-forcing su:;, so um the comarninarn:s 1l'C stripped from said soil or wmcr. via a mass-<r3Dsfcr process. by the flowing gas. db:n::by placing the e:min: zone under maximum rcmc~ -':5 dimioasoas. 2. The metl!od as ddin<d in cl.aim 1. whacn. at least 31 and below said imaicrcace poinr. said coae bas a surface of n:wlurioa having a an:mnie,,:na: detlniag a rin:ular base. 3. The method as deilncd in cl.aim 2. furtbcr comprising ,a • h ~ 1i11g said distance so r.hat a line from said vertex to U1c ri,.cumfiua,cc uf said rircular ba3e forms aa aagle of appn,ximau:!y 45" with Ille uis of n:volwion of each com:. 4. The mctllod as deilncd in cl.aim 3. furlller comprising forming said two bore holes so t1m they exlCld Yfflically 10 55 said d.eptil bc:aear.11 said I I ri Ii Iii I a.rd an:a. · 5. Thc mcmod as ddin<d in claim 4, whcn:in said sparing disamcc is eauai 10 or less tllaa twice said dc!>tl>-6. The mcmod as derined in claim S. when:m said forcia~ szcp """'!)rises forcing a gas Wider positive ?=SIi"' in10 60 said two bore holes., 311d whemn said gas dows lll""'fflly. witlmw. "l'l'licatioa of any YllCUWD or negative pn:ss,=. along said parbs 10 said surface. 11. The m=bod as dcnD:d ia daim 2. furtbcr wmµ,:ising forming said two ban: holes SD dial they exu:ad in a din:aion bcnoo:eD bonmmal and vmica1 10 said sumc::. 19. The lll<lhDd as ddim:d in claim 18. wlu:n:in said fon:mg step COtD!Jri= fcm:imi a gas uad.er positive pn:ssurc into said two ban: holes. md when:in said gu flows upwazdly. W1tllout "!'PUC:iaaa oi any vaaium or aeguive pn:ssmc. alaag said pa1lls 10 said sun'acc. :!II. The method as ddincd in d:iim 1. when:in Ille gu at tbe c:mr.mo: of =n ban: bole 113s a dow r= from awroxi-amdy 0.04 10 O. l cubic fee,: per mimw: per squan: foot of eadl bore bole"s =a of~ n. The metllod as dcfuicd in claim 1. furtber comprismg tbe Steps of tr:rmimting said purging. afa:,-a lint time period of aper.moo. for a second time period suJ!icicm 10 allow smic coaditions 10 n:mm aod 10 allow any induced pn:icr-c:mial patllways 10 he:,L before again initiann~ said ptqing. :!2. The mabod as detiocd in claim 21. wbcrem said fon:mg step annpriscs t'on:iag a gas uad.erpositive pn:ssurc inm said lWO bore boles, aod whcn:in said gas 8ows "lJW'l'diy. W1tllout .q,plicatioa of any vacuum or ncgalive pn:ssmc. liong said paths 10 said sun'acc. 23. The method as ddmcd in claim 1. funhcr comprising the szcp of forming addilioml said bore holes around • boundary perimeter of said crnuan:rinarcd zone lO prevent horizoma.l Qiliiilll. I migrarion. l4. The lll<lhDd as ddmcd in claim 1. funhcr comprising the szcp of ciloosing said aiswia: 10 be equal 10 or las tllaa twia:saiddc!>tl>-25. The method as ddim:d in cl.aim l. wlu:n:in said fon:mg SICl COIDlfflSCS lim:mg a gas uad.er positive pn:ssurc ima said two bore holCL md wherein said g::is flows ._.-dly. W1lhout .q,plicai:ion of :my vacuum or neganve 7. The method as deaned in cl.aim 5. when:in said gas is 41DDSµbuiG :iir. ., pn:ssmc. along said µallls 10 said surfac:. 8. 11M: mctnod ;is dcrincd in ciaim 7. wherein said amtaminau:d. tone is bctow a water ubtc in lhc c:utn. 26. The mctnod ;ii dcrincd in ctiim 1. whc:n:in s.:iid gas is aunospttaic J1r.
g
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5,509,760
9
-rt. The =lloci as ddim:d in daim I. wbcn:in said
maraarioarn:1 mnc is bciow a wau:::r table in the earth.
:ZS. The mcwxl as ddim:d in daim I. wbcn:in said
surface of the c:arl!I remains exposed ID Ille cm11l' S amx>-
sphere tllrougbaul mi, pc:tfmuwaz af said SICpS.
29. The mcuzod u ddim:d in claim I. wbcrciD said lcYd
is cmin:ly bcncalll said . I I ,._,
10
30. The IDClllod as deaned in daim I. whcn:in said
..,.,..,.,,aams uc purged frum said cmraminved mae only
by slripping. via said ~ .md witiloul biodcgra-
' daiOD of tDt' amrzm:iamn
• • • • •
GROUND
SURFACE
f I G. I
AIR ENTRY REMEDIATION AIR ENTRY
POINT / STRESS AREA ( POINT
----L--------{l---,-------,L-jl---f---\---7·1-------------:/~
' /
' /
' /
' WATER'\ , /
TABLEJ ', /
~------------' / / ---~~-~ /
', / ' ' / ' ' / ' , / INTERFERENCE',
' / POINT ,
' -----DEAD ZONE}
/
/
/
/
/
J;l
....
0 ....
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. U.S. Patent
MW-6 •
MW-II •
Apr. 23, 1996
• MW-2
Sheet 2 of 9
FIG.2
PLUME
EXTENT
5,509,760
{ 1 ug/1 BENZENE)
MW-14 • MW-I
II C.
MW-i9 •
~ ----.._ . .,,.,,... MW-17 ...._ .,,. ......
/ o e □ ',
/eMW-15 '\
C. I 6 ~-I M~-16 \ MW-18
/ 11 r---,7--f _a.. __
/ MVf:-13 0 • 1 1 •
I
-MWt-6 □ I ,____.-+-.,.,_ __ _
I O I, / Ii/
C. I C. C. c.: /~ HORIZONTAL
I MW-l2: / TREATMENT
I MW-20 □ e j POINT
\ • / 1C.
~-----~ ,,..✓ I _____ ..-._. I
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~CAVATION 7--
BOUNDARY
~ TREATMENT POINT
{AIR ENTRY WELL)
□ AIR EXIT POINT
MW-7
e
AIR ENTRY WELLS WERE 25ft OEEP,!Sft APART.
GROUNDWATER CLEANUP TlME WAS 7 DAYS .
CONTAMINANTS WERE BTE< -t-MTBE.
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-U.S. Patent Apr. 23, 1996 Sheet 3 of 9
RAILROAD TRACK
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:. ~000 FENCE
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WEST 6th A11e.
MW-7 e
MW-5 e
MW-10 e
1 TP-9
: CONTAMINATION o.
1 PLUME EXTENT TP-I3 ....--.. e,,TP-l7 ~ _IJF.S
TP-I2;:. I Ci. ~6eMW~3
/ 0,a....;MW-9
TP-llc. I TP-7 b.TP--15
TP-2 '1 ~h W-2 r. ~ b.TP-1
MW-I5e I ar---JMW-6
, s-;:rP-3
TP-IQC. ,__.., 0 TP-I4 C.TP-6
MW-II
e
EBMW-8
ATP-5
EBMW-I4
5,509,760
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0,-TREATMENT POINT
(AIR ENTRY WELLS)
eMWt2 PLAZA
(OFFlCESl
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FIG.3
eMW-l3
PLAZA (OFFICES)
TP3,4,6,7,8 S9 ARE 25ft DEEP.
ALL OTHERS ARE 17ft DEEP.
AREAL SPACING IS 18ft APART
STARTlNG CONC.= 8100 ug/t PAH's
ENDING CONC. = 35 ug/1 PAH's TARGET= IOOug/I
REMEDIATION Tl ME= 8 DAYS
±25 cfm per TP
- - - - - - - - - -l!!!!!!!!!!I !!!!!l!!!!I !!!!!:I == liiiiiiil iiii iiii - -
FIG. 4
REMEDIATION INTERFERENCE
STA ES S ~
AREA ,
" \
'
HORIZONTAL
Al R ENTRY
POINT
POINT
d • CJl •
..
'C
/ :,
/ t1 • ... \Q \Q
0\
-

-

-

-

-

-

-

-

-

-
11!!!!1 I!!!!!!!! ~ . == lliiliiiiiiil iiiii iiiil -

-
GROUND
SURFACE
WATER
TABLE
' ' ' ' ' ' ' ' '
'
Fl G • 5
REMEDIATION
STRESS AREA
' / ' / ' /
INTERFERENCE ~//
POINT .__....-•
' ' ' '
DEAD ZONE ---
DIRECTIONALLY
INSTALLED
AIR ENTRY POINTS
/
/
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/
/
/
/
/
/
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· U.S. Patent Apr. 23, 1996 Sheet 6 of 9 5,509,760
-
Fl G . 6 REMEDIATION TIME
GROUND WATER TEMPERATURE , 68 ° F
ONE 5 HOUR CONTINUOUS OPERATlNG
CYCLE PER DAY
EXAMPLE# I
.......--'--.......,~---GROUNDWATER CONC. 20000 ug/1 BTE X.
REMEDIATION TARGET, IOug/1
l80AYS-30AYS = IS DAYS MAX. TO
REACH TARGET
51.~--+--f--+--++-+--+-*-+--+-+--+--+---t--
~
~ z :::,
0 a: c:, QUICK
c:, 10 PURGE
z =r--,.t---i---t--t--t-~PERFORM ~-+--+--t--r--
z CE AREA
< ::E
UJ a:
0 2 6 8 10 12 14 16 18 20 22 24 26
TIME (DAYS l OR NUMBER OF DUTY CYCLES
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500 0
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100 0 \
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0
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a:
Apr. 23, 1996 Sheet 7 of 9
FIG.7
CONTAMINANT REDUCTION
RATES IN SOILS
I
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\ ' \ I '
i\ \ I \ "\ ;.:a-s I
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\ I\ 'Y I
\ •\ I \ ' I
\ I\ \ \ I
\ \S~-4 \\
~a-11--\ \ \
o I
~
oo' \
SB-~ \ \
-<! ~ -
10
\ I I I
\ I
\ I I\ \ I
\ I . I \ \
i\ I \ ' I \~a-14 \ \
\ \
I\ i\ \
I \ \ \ I\
0 I 2 3 4 5 6 7
NUMBER OF CYCLES
5,509,760
f I G. 8
PRESSURE
GAUGE
SECONDARY DISTRIBUTION ·
MANIFOLDS WITH VALVES
AND 4 ADJUSTABLE AIR
FLOW RATE GAUGES
~
/ ---I
I
l ,~
\ AIR
COMPRESSORl--l--t~ L---------..i J------i~'
PRIMARY
DISTRIBUTION
MANIFOLD WITH
VALVES
.-...... _ _,,,
fl , AIR ENTRY POINTS'.'.::'.:-----_...
CONTAMINATED
AREA
/
/.
\~
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[
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g,
"'
----

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-

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FIG.9
/ ..
CONNECTION
BUSHING
1/,
2 -INCH DIAMETER
PVC RISER •
BOTTOM CAP
CONNECTION FIG .10 BUSHING
,._~ 2-INCH DIAMETER
PVC CASING
4.5-INCH DIAMETER
d en •
;..
'ti rs
· -wEtL-BORE ----. Ll
•
CEMENT GROUT
i;..,. __ _, I-INCH DIAMETER
PVC CASING
:r (: .,. -'•· F -:\---SLOTTED SCREEN
D (, ___ SAND PACK
BOTTOM CAP