NCG510110_Regional Office Historical File Pre 2018 (2)

Michael F. Ea.s.ley, Governor
William G. Ross Jr.. Se,cretary
North CaroItna Departmeni of Environment and Natural Resources
Alan 'W. Klimek, P. E. Director
Division of Water Quality
Coker, H. Sullins, Deputy Director
Division of Water Quality
May 5, 2004.
Ms. Debbie Sailors
Petroleum World, Inc.
681 NC Highway 120
Mooreshoro, NC 2811.4
Subject: Rescission of NPDES General Permits
Permit Numbers NCG510019, NCG510356 & NCG510311
Petroleum World_Inc„ Sites
Bob's Superette, G&J Foodway and Banoak Food sites
Catawba & Lincoln Counties
Dear Ms. Sailors:
Reference is made to the recent requests for rescission of the subject NPDES General Permits that were
submitted on your behalf by Shield Engineering, Inc. The letters state groundwater remediation activities
have ceased at the subject. sites and therefore they no longer require coverage under the general permit, in.
accordance with your requests, NPDES General Permits NCG5110019, NCG510356 & NCG5103I 1 are
rescinded, effective immediately.
Please he advised that these permit rescissions are based wholly upon your statement that the activities
which would require general perrnit coverage. at the sites have ceased or been eliminated. Division staff
has not visited. the sites to obtain independent verification. Operating a treatment facility, discharging
wastewater or discharging specific t)pes of stormwater to waters of the State without a valid NPDES
penultwill subject the responsible party to a civil penalty of up to $25,000 per day. Enforcement action
will be certain for persons that have voluntarily relinquished permit coverage when, in fact, continuing
permit coverage was necessary. If, in retrospect,you feel the site still .requires permit coverage, you
should notify this office immediately. Furthermore, if in the future you wish to again discharge to the
Stales surface waters, you must first apply for and receive a new NPDES .permit,
If you .have questions about this matter, please contact Bob Sledge at (919) .xtension 547 or
the Water Quality staff in our .Mooresville Regional Office at (704) 663-.1699,
Sincerely,
Alan W, Klimek, P.E.
cc: Mooresville Regional Office w/attach nts
Stormwater & General Permits Unit
Point Source Compliance — Bob Sledge w/attachments
Central Files - w/attachments
Fran McPherson, DWQ Budget Office
WAT
'T. OF EN Nit:lilt
TURN,. 94ililOURCES
SV' - OFFICE
:11
MAY 1 1 2004
Division of Water
[phone]
uahtv
1617 Mail Service, Center
Fa. (919)733-96.12
Raleigh, ,NC 27699-.1617
Customer Service
1 877 623-.7748

ENGINEERING, INC.
April 23, 2004
Ms, Fran McPherson
Annual Administering and Compliance Fee Coordinator
Division of Water Quality
North Carolina Department of Environment
and Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: Annual. Permit Fee and Request for Permit Recision
NPDES Permit No. NCG510019
ob's Superette
GWI Number #5117
Shield Project 1950069
Dear Ms, McPherson:
On behalf of Petroleum World, Inc. (PWI), Shield Engineering.. Inc. (Shield) submits this letter informing
you that PWI will not be renewing the NPDES permit for the subject site, and requests that this permit be
rescinded. This project received a No Further Action from the North Carolina Department of -Environment
and Natural Resources. Division of Waste Management on December 18,, 2002. The treatment system is
no longer in use and has been permanently removed from the site, A copy of the renewal invoice and No
Further Action Letter is attached.
Sincerely,
SHIELD ENG. RJ,NG, INC
Michael D. Armour, P,G.
Principal
Registered, North Carolina # 1209
Attachments
Field Services Manager
cc: Debbie Sailors, Petroleum World, Inc., Mooresboro, NC
Taggar7 Cry
)11e. NC 2620E
cts I 9951.95O069LETTERS`=4-23-04 NPDES Rescind Leltes.doc
k+Gvv+v.shieldengTneeranq.cam
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ENGINEERING, INC.
April 26, 2004
I\4s, Fran McPherson
Annual Administering and Coniphance Fee Coordinator
Division of Water Quality
North Carolina Department of Environment
and Natural Resources
1617 Mail Senice Center
Raleigh, North Carolina 27699-1617
Subject: Annual Permit Fee and Request for Permit Rescission
NPDES Permit No. NCG510356
3 Foodway
GWI Number 612519
Shield Project 1950019
Dear Ms. McPherson:
Or: behalf of Petroleum World, (PWI), Shield Engineering, Inc. (Shield) submits this letter
informing you that PWI will not be renewing the NPDES permit for the subject site, and
requests that this permit be rescinded, The groundwater recovery and treatment portion of the
remedi anon system is no longer in operation and is no longer needed at the subject site. The
North Carolina Department of Environment and Natural Resources, Division of Waste
Management UST Section agrees that the renewal of the pennit is not necessary. A copy of the
renewal invoice is attached for reference.
Sincerely,
SHIE1,13 ENGINEERING INC
Michael D. tour, LG.
Principal
Registered, North Carolina 41209
Attachnionis
Kevin A. impson
Project Manager
cei Debbie Sailors, Petroleum World, Inc., Mooreshoro, NC
Brad Newton, NCDENR-MRO
HProiects '3995 1950019APDES RCATind Lever dor
Taggart Creek Road
one, NC 28208
www skkeldenrgineenng corn
Telephone [phone]
Fax [phone]
1

SHIELD
ENGINEERING, INC.
April 26, 2004
Ms. Fran McPherson
Annual Administering and Compliance Fee Coordinator
Division of Water Quality
North Carolina Department of Environment
and Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: Annual Permit Fee and Request for Permit R+eseission
NPDES Permit No, NCG510311
Banoak/Martins
GWI Number #5340
Shield Project 1950049
Dear Ms. McPherson:
On behalf of Petroleum World, Inc. (PWI), Shield Engineering, Inc. (Shield) submits this 'fetter
informing you that PWI will not be renewing the NPDES permit for the subject site, and
requests that this permit be rescinded. The groundwater recovery and treatment system is no
longer in operation and was removed from the subject site in April 2002. The North Carolina
Department of Environment and Natural Resources, Division of Waste Management UST
Section agrees that the renewal of the permit is not necessary. A copy of the renewal invoice
is attached for reference.
Sincerely.
SHIELD ENGINEERING, INC..
Michael D. Armour, LL.G. Kevin A. Simpson
Principal Project Manager
Registered, North Carolina #1209
Attachments
cc: Debbie Sailors, Petroleum World, Inc., Mooresboro, NC
Brad Newton, NCDENR-MRO
1f:IF''rojeciss199519i0O49APDESRescind Letrer-Banoak_floc
Taggar Creek Road
otte. NC 28205
www.shleldengneenng.cam
Telephone 704 394,6913
Fax [phone]

June 25, 2003
Ms. Debbie Sailors
Petroleum World, Inc.
681 NC Highway 120
Mooresboro, NC 28114
Michael F. Easley, Governor
JUN 2 7 2003
WATER QUALITY SECTION
Subject: Requests for Rescission of NPDES Permits
Permit Numbers NCG510019, NCG510356 & NCG510311.
Petroleum World, Inc. Sites
Bob's Superette, G&J Foodway and Banoak Food sites
Catawba & Lincoln Counties
Dear Ms. Sailors:
Reference is made to your requests for rescission of the subject NPDES General permits,
submitted on your behalf by Shield Engineering, Inc. Responses regarding each of the subject
facilities/permits are provided below.
NCG510019; Bob's Superette
Request Summary
The submittal states the Division of Waste Management (DWM) has certified that no further
action is required to remediate the site. The treatment system is not being used and will be
removed at a future date, and therefore the site no longer requires coverage under the general
permit.
DWQ Response
Upon receipt of a statement from you that the on site treatment system has either been removed
or that it has no potential (ability) to discharge, the Division will promptly rescind NPDES
general permit coverage. Until that time, you are required to abide by all terms of the permit,
including payment of annual permit fees.
NCG510356; G&J Foodway
Request Summary
The submittal states the site is scheduled for soil excavation that will preceed issuance of a No
Further Action certification from DWM. DWM's UST Section has stated it will not approve the
costs of the annual permit fee and therefore, the fee invoice has been returned along with a
request for rescission of permit coverage.
Customer Service
1 800 623-7748
division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617
[phone] Fax: (91'9) 73:3 E'a12

DWQ Response requirepermit
No evidence has been provided as to whether the circumstancesatne site, is onalDES has
coverage have ceased. If the treatment system fetatn coverage a under the permit. As long as the
potential for a discharge, it is necessary g payment of the annual
permit is in effect, the permittee Pe zpleurneWo ld all ©f its mac ,lerms, and it is not relevant elepan whether or not the
fee. This is the responsibility o and
$80.00 fee will be paid by the UST trust fund. The expectation ©iesfor
last
f tpyear
the
e current year are
being returned to you along with this letter, with an
t.
NCG510 I $ nroak Foods
Request Sum wry see if
The submittal states the site is currently being evaluated
twater supply,aditional
remhdia would eliminate
necessary or if local residents can be connected to public
the need for continued remediation. It further stated that you had been denied reimbursement for
the annual permit fee from the UST trust fund.
DWQ Response
The submittal provided no evidence that either the
ee in there �ous discussion,site
ii the treatment
for continuing permit coverage has ceased. As statedpev
system remains at the site, is operational and has potential for a discharge, it is necessary to
retain coverage under the permit. As long as the permit is in effect,
ff f et, the the permittee must abide
de by
or
all of its terms, including payment of the annual fees. The in
the current year is returned along with this letter with the expectation of prompt payment.
With regard to each of these matters, when you provide statements that will be abide charrgc nh the
es have
ceased and the treatment works have been removed, the pleaseis atter, contact Bob Sledge at
permits without delay. If you have questiothe ns r Qualitybout tstaff in our Mooresville Regional Office at
[phone], extensionor
[phone]. Thank you for your cooperation.
Sincerely,
cc: Mooresville Regional. Office wlattachments
Stormwater & General Permits Unit
Point Source Compliance — Bob Sledge - wlattachments
Central Files - wlattachmnents
Fran McPherson, DWQ Budget Office
Mr. Michael D. Armour, P.G.
Shield Engineering, Inc..
4301 Taggart Creek Road
Charlotte, NC 28208

May 15, 2003
Ms. Fran McPherson
Annual Administering and Compliance Fee Coordinator
Division of Water Quality
North Carolina Department of Environment
and. Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: Annual Permit Fee and Notice of Permit Rescinding
NPDES Permit No. NCG510019
Bob's Superette
GWI Number #5117
Shield Project 1950069
Dear Ms. McPherson:
On behalf of Petroleum. World, Inc. (PW1), Shield Engineering, Inc. (Shield) submits this letter informing
you that PWI will not be renewing the NPDES permit for the subject site, and requests that this permit be
rescinded. This project received a No Further Action from the North Carolina Department of :Environment
and Natural Resources, Division of Waste Management on December 18, 2002. The treatment system is
no longer in use and will be permanently removed from the site at a future date. The renewal invoice is
attached.
Sincerely,
SHIELD ENGINEERING, INC.
Michael D. Armour, P.G.
Principal
Registered, North Carolina # 1209
cc: Debbie Sailors, Petroleum World, Inc., Mooresboro, NC
430't Taggart Crk
Charlotte, NC 28208
995119501)69TTERS''5-1-t13NPDES Rescind Letter.doc
ngineering,cnm
Telephone 704,394, 6913
Fax 704,394.6968

SOC PRIORITY PROJECT: Yes No x
To: Permits and Engineering Unit
Water Quality Section
Attention: Charles Alvarez
Date: August 26, 1993
NPDES STAFF REPORT AND RECOMMENDATION
County: Catawba
Permit No. fCG51O11O
PART I - GENERAL INFORMATION
1. Facility and. Address: BoRhbodesF&©d BealOil
Mart c/o
1404 East Main Street
Lincolnton, NC 29092
2. Date of Investigation: 08-23-93
3. Report prepared By: Samar Bou-Ghazale, Env. Engineer I
4. Persons Contacted and Telephone Number: Mr. Ted A. Goodman,
Hydrogeologist of Handex; [phone]
. Directions to Site: The site is located on the west side of
NC Hwy 127, approximately 250 feet west of the intersectionCof
NC 127 and Moss Farm Road (SR 1149) in Catawba County,
6. Discharge Point(s). List for all discharge points:
Latitude: 35° 41' 06" Longitude: 81° 22' 24"
Attach a•U.S.G.S. map extract and indicate treatment facility
site and discharge point on map.
U.S.G.S. Quad No.: E 13 NE U.S.G.S. Name: Hickory, N.C.
7. Site size and expansion are consistent with application?
Yes, x NoIf No, explain:
8. Topography
relationship to flood plain included): Sloping
southeast toward
locat di in a flood plains rate of 2 to 3
The site is no

9. Location of nearest dwelling: The nearest house is located on
the East side of NC Hwy 127, approximately 130 feet across the
Highway from Bob's Food Mart.
10. Receiving stream or affected surface waters: Unnamed
tributary to Hop Creek.
a. Classification: WS-III
b. River Basin and Subbasin No.: Catawba ; 030835
c. Describe receiving stream features and pertinent
downstream uses: Discharge will take place into a storm
drainage system located on the East corner of Bob's Food
Mart. The storm drainage system outlet pipe is located
on the East side of Hwy 127 approximately 200 feet below
the site. The receiving water course is a dry ditch that
flows through a residential area.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of wastewater to be permitted: 0.101 MGD
(Ultimate Design Capacity)
b. What is the current permitted capacity of the wastewater
treatment facility? N/A
c. Actual treatment capacity of the current facility
(current design capacity)? N/A
d. Date(s) and construction activities allowed by previous
Authorizations to Construct issued in the previous two
years: N/A
e. Please provide a description of existing or substantially
constructed wastewater treatment facilities: N/A
f. Please provide a description of proposed wastewater
treatment facilities: The proposed wastewater treatment
system will consist of monitoring wells, recovery wells,
oil/water separator, air stripper, and an activated
carbon adsorption unit.
Possible toxic impacts to surface waters: None expected.
g.
h. Pretreatment Program (Wren only): N/A
NPDES Permit Staff Report
Version 10/92
Page 2

2. Residuals handling and utilization/disposal scheme: Generation
of residuals is not expected.
3. Treatment plant classification (attach completed rating
sheet): Proposed, no rating given
4. SIC code(s) : 5541
Primary: 66 Secondary: Main Treatment Code: 5600
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant
Funds or are any public monies involved (municipals only)?
N/A.
2. Special monitoring or limitations (including toxicity)
requests: N/A.
3. Important SOC, JOC or Compliance Schedule dates: (please
indicate) N/A.
4. Alternative Analysis Evaluation:
Spray Irrigation:
Connection to Regional Sewer System:
Subsurface:
Other Disposal Options:
PART IV - EVALUATION AND RECOMMENDATIONS
Rhodes & Beal Oil Company, is requesting an NPDES General
Permit for the discharge of treated groundwater resulting from a
leaking underground gasoline storage tank (UST) at Bob's Food Mart.
The proposed method of treatment is typical of treatment
methods used by the petroleum industry for similar groundwater
remediation activities.
Field investigation revealed that after discharging from the
facility into a storm drainage system, the proposed treated
groundwater exits into a dry ditch approximately 200 feet from the
discharge point into the storm drain. It then flows approximately
900 feet to an unnamed tributary to Hop Creek through a residential
area.
NPDES Permit Staff Report
Version 10/92
Page 3

Because h proximity to adjacent residences, the applicant
should be required to demonstrate that the proposed facilities will
not create nuisance problems (noise, odors) prior to issuance of an
Authorization to Construct.
is ended that the PDES Permitbe issued.
DES Permit Staff Report
Version
Page

PROPS CROSSRC4CS 4,4 Mk
a
0755 I/I NW
(LONGVI£W)

to of North Carolina
Department of Environment,
Health and Natural Resources
/ Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
Mr. Wendel Boggs
Rhodes & Beal Oil Company
1404 East Main Street
I..incointon, NC 29092
August 9, .1993
Subjects Application No. NCG51.0110
Additional Information Request
Bob's Food Mart
Hickory
Lincoln County
Dear Mr. Boggs:
The Permits and Engineering. Unit has completed a preliminary engineering review of the subject
application.
Thee fbllowi.ng items must be addressed before we can complete our review:
1) Please document the cost of connecting to the available sanitary sewer versus the cost of
discharging to the surface waters of the State.
2) For new facilities, final plan layout, including connection of piping systems., must be
submitted signed and sealed by a North Carolina registered Professional Engineer. A
plan of the remcdiation equipment in relation to other features at the site (such as roads,
buildings and wells) with buffer distances from property lines (50 feet from property
lanes), and the location of the discharge point needs to be signed and sealed by a
registered Engineer,
3) A copy of calculations of removal efficiencies for benzene, toluene and other
constituents of interest expected to be obtained using the treatment equipment.
Refer to the subject permit application number when providing the requested information. Please
submit three copies of ail information to my attention at the address below. Also, please
note that failure to provide this additional information on or before September 1.0, 1993 will subject your
application to being returned as incomplete, in accordance with 15A. NCAC 2H .0208.
Regional Offices
Asheville Fayetteville Mooresville R.alefgh Washington r'ihriingtort Winston-Salem
704/251-6208 919/486-1541 704/663-1699 919/571-4700 919/946-6481 919/395-3900 919/896-7007
P.U. Box 29535, Rai.
An Equa
Pollution Prevention Pays
1, North Carolina 27626-0535 Telephone [phone]
Opportunity Affirmative Action Fmpldv"er.

Mr. Wendel Boggs
August 9, 1993
Page Two
If you have any questions nn this matter, please. a at 1 w:
Sincerely,
Permit File NCG510110
Handex, Inc,„ Mike Jones
Charles A. Al
Environmental Engineer.
NPDES Group

James G. Martin, Governor
William Yvr. Cobey, Jr., 'Secretary
State of North Carolina
Department of Environment, Health and Natural Resources
Division of Enrirorrtnental Management
512 North Salisbury Street • Raleigh, North Carolina 27611
A. Preston Howard, Jr., Pa .
Ac tin g Director
NOTICE OF INTENT
National Poll t nt Discharge El rnination System,
Application for Coverage under General Permit NCG510; Grog nd'v'ate'
designed to treat petroleum contarninated groundwater.
1, Name, Address , location, and telephone number of facility requesting Perr .it.
Bob's Food Mar t c / o Rhodes & Bea
A. Official Name:
B. Mailing Address: n r Wendel Boggs
(i)Street Address;
(2)City;
(3)State;
(4)Zip;
(5)County;
C. Location. (Attach map delineating general
(1)Street Address;
(2)City;
(3)State;
(4)County;
Fact
C.
D.
Telephone Number;
Contact:
Name;
Title;.
Company Name;
Phone Number;
)N/A
Rhodes & Beal Oil Co. c
Senior Project Manage
Beal Oil Co.
4 725 2508
Application type (check appropriate
A. New or Proposed; K
B , Existi'ng.
C„ Modification;
e nature of the modification
Description of discharge
A. Please state the nurnber of separate discharge points.
LEA; 2,[1; 3,[I; 4,[1; 1,
selection):
n projects
Oil Co.
o MikeJ(Hande�X of the
��ones Carolinas, Inc.)
Wendel Boggs
If previously permitted, provide permit number
and issue date
Page 1

B. Please describe the amount of wastewater being discharged per each separate discharge polnt
1101_2:gallons per day (g-pd) 2: (-gTxi) 3: ) (6 xi) ( EST )
C. Check the duration and frequency of the discharge, per each separate discharge point:
1. Continuous:
2, Intermittent(
3. Seasonal (check month(s) theJanuary .; February [ March k]; Apn
May [June id; 'July it August [)1; September W..;Octoberik November W; Decnmber 4.
4. How many days per week is there a discharge?(check the days the discharge occurs)
Monday ()I, Tuesday kb Wednesday W, Thursday kl.,Friday kJ Saturday [xl, Sundayki.
5. How much of the volume discharged is treated? (state inpercent) 1 ()0 57c
REFER TO ATTACHED . • RFIVE ACTION PLAN FOR. SErIa4.D & 4. 6-10
D. Describe the type of wastewater being discharged per separate discharge point. Specify what is
being removed and products recovered. This includes a listing of any Chemicals found in
detectable amounts with the maximum observed concentration reported. The summary of
analytical results containing this maximum value should also be submitted (i.e, the listing, not
the graphical scan). The most recent sample must be no older than one year previous to the date
of this application. The .following volatile organic compounds should be included along with
any suspected fuel additive;
1. Benzene";
2. Toluene*;
3. Ethyllpenzene;
'Xylene"-;
5. Lead;
Methyl tert-butylether (MThE);
7. Dibromoethane (EDB);
8. 1„2-dichloroethane;
9. Isopropyl ether;
10. Naphthalene;
11, Phenol;
'(An EPA approved method capable of detection levels to 1 ppb should be used to detect these
cornixpunds).
E. Please check the appropriate type of treatment being used to treat the ground
1. Ol/Water Separator; x
3.
Air Stripper;
Diffused Aeration;
4, Activated Carbon Absorption; v
5. Othenspedfy);
a er;
6. Separately, please describe in detail(size, vo urne,capacity, desxgn flow through treatment,
etc.) each type of treatment that was checked in 1 through 5. Include, if any, the
rnanurac-turer5 nformation on each type of treatment. Also provide the removal efficiency of
each compound detected for the project, if known. Give design specifics (i.e. design volume of
each unit, materials used in air stripper, etc.). Existing treatment facilities should be
described in detail and design criteria or operational data should be provided(including
calculations) to ensure that the facility can comply with requirements of the General Permit.
Please include model and calculations used in determining the design requirements for the air
stripper.
7. Vslhat are the well sizes and how many exist
8. Please state the pump sizes and their location in relation to the treatment used in part
9. Please ex -plain what fail-safe measures, such as audible and visual alarms or automatic
shutoff systems, are provided to ensure no system failures.
10. is there an access to the effluent for sampling?( either an open pipe or a valve to obtain a
sample)
Page 2

Pr
' :,----4(51.E: Construction of any wastewater treatment facilities require submission of three (3) sets of plans
and spe.cifications along with their application. Design of treatment facilities must comply
with requirement 15A NCAC 2H. .0138. if construction applies to the dis.-..charge, include the
three sets of plans and specifications with the application.
5, What is the nature of the business applying for this permit.
Retail Food Market
6.. 1,,,:arrie of receiving water or waters; Classification:
(Attach a USCS topographical map with all int(s clearly marked)
Is the discharge directly to the receiving w.aterNY,N) NO
If no, state specifically the discharge point. Mark clearly the pathway to the potential receiving
waters on the site map, (This includes tracing the pathway of the storm sewer to its discharge
point, if a storm sewer is the only viable means of discharge.)
S, Pease address possible non -discharge alternatives for the following options:
REFER TO CORRECTIVE ACTION PLAN, SECTION 8. 8 (page, 2j)
A,. Connection to a Regional Sewer Collection System;
c,'Libsurrace DiSpOSal;
pray Irrigation;
9,. I certify that I am .farniliar with the inforrnatian contained irt the application and that to the best of
my knowledge and belief such information is true, complete, and accurate.
Pnni Nain of P
Date Application Signed.
Signature of Applicant
Any person who knowingly makes any false statement, representation, or certification in any
application, record, report, plan or other document filed or required to be maintained under Article 21 or
regulations of the Environmental Management Corrin-Ussion implementing that Article, or who falsifies,
tarnpers with or knowingly renders inaccurate any recording or monitoring device or method required to
be operated or maintained under Article 21 or regulations of the Environmental Management
Commission implementing that Article, shall be guilty of a misdemeanor punishable by a rine not to
exceed $10,000, or by imprisonment not to exceed six months, or by both. (18 USC. Section )001 provides
a punishment by a fine of not more than $10,000 or imprisonment not more than 5 years,or both, for a
similar offense.)
Notice of Intent must be accompanied by a check or money order for $40C,00 made payable to the North
Carolina Department of Environment, Health, and Natural Resources. Mail three (3) copies of entire
package to:
Division of Environmental Management
NPDES Permits Group
Post Office Box 29535
Raleigh, North Carolina 17626-0535

CO RECTIVE ACTION
FOR T-
ROUTEBOB'S FOOD MART
NORTH1
Handex Project 4 -0
PreparedFor:
RHODES AND BEAL OIL COMPANY
1404 Fast Main Street
Lirlrter, N.C. 29092
eparc# 6
Michael C. Jones, Ra
Senior Project Manage
Prepared
HANDEX OF THE CAROLINAS, INC.
}-G WOODPARK BOULEVARD
CHARLOTTE, NORTH CAROLINA
March
1 2, 93
AUG'

Figure 1 :
Figure 2:
Figure 3 :
Figure 4
Figure 5:
Figure 6 :
Figure 7 :
Figure 8 :
Figure 9:
Figure 10 :
Figure 11 :
Figure 12
Figure 13 :
Figure 14
Figure 15
Figure 16 :
Figure 17 :
Figure 18 :
Figure 19
Table 1 :
Table 2
Table 3
Table 4
Table 5 :
Table 6
Table 7
TABLE OF CONTENTS (Continued)
FIGURES
Topographic Map of Surrounding Area (SGS Report 9-92)
Site Plan
Water Supply Wells (SGS Report 9-92)
Cross Sections Line Map (SGS Report 9-92)
Cross Section A -A' (SGS Report 9-92)
Cross Section B-B' (SGS Report 9-92)
Cross Section C-C' (SGS Report 9-92)
Cross Section D-D' (SGS Report 9-92)
Water Table Contour Map - Nonrestrictive Flow (SGS Report 9-92'.
Water Table Contour Map - Showing Bedrock Influence (SGS Report 9-92)
Benzene Concentration Map (SGS Report 9-92)
MTBE Isoconcentration Map (SGS Report 9-92)
BTEX Concentration Map
Projected Capture Zones - 2 Vacuum Enhanced Wells (1.0 GPM)
Projected Capture Zones - 2 Vacuum. Enhanced Wells (2.0 GPM)
Projected Capture Zones - 2 Vacuum Enhanced Wells (3.5 GPM)
Conceptual Remediation Plan
Recovery Well and Piping Layout
Recovery Well Detail
TABLES
Ground Water Analytical Results Summary (SGS Repor
Soil Analytical Results Summary (SGS Report 9-92)
Predicted Vacuum Enhanced Pumping Results
Timeline for Installation and Remediation Tracking
Summary of Cleanup Standards and Discharge Criteria
Air Stripper Design Concentrations
NPDES Discharge Criteria
APPENDICES
9-92)
APPENDIX A : CORRESPONDENCE WITH NCDEHNR
APPENDIX B : GROUND WATER MODELING DATA AND RESULTS
APPENDIX C : OIL WATER SEPARATOR/AIR STRIPPER DESIGN & SPECS,
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1.0 INTRODUCTION
The following presents the Corrective Action Plan (CAP) for the Rhodes 8, Beal Oil
Company, Bob's Food Mart Facility located at Route 8, Box 122, in Hickory, North
Carolina. The Site Assessment. Report for the facility was submitted in September 1992,
to the North Carolina Department of Environment, Health, and Natural Resources
(DEHNR), Division of Environmental Management (DEM) in Mooresville, NC, The
assessment reports were approved by DEM and a CAP was requested for the site. The
due date for the CAP has been extended to March 12, 1993. The CAP extension letter
is presented in Appendix A.
1.1 OBJECTIVES
The goal of the proposed corrective actions is to remove hydrocarbons from the affected
ground water and soil quality. These remediation efforts should be guided by the level
of risk to the population, the standards set by the State of North Carolina, and the level
of effort economically and technologically advisable. The objectives of the CAP are to
provide a plan to accomplish the following goals:
• Establish hydraulic control over the core of the hydrocarbon plume in the source
areas and control downgradient migration of hydrocarbons.
* Removal of Liquid Phase Hydrocarbons (LPHs) from the water table if present;
• Reduce dissolved phase hydrocarbons (DPHs) in ground water to risk based
closure levels;
• Removal of residual hydrocarbons in unsaturated soils which may act as
continuing source of dissolved hydrocarbons to ground water.
The CAP was prepared to evaluate approaches to cleanup of petroleum hydrocarbons
and includes a comparison of cleanup approaches based on technological sound
remedial methods, cost considerations, site conditions, and recovery endpoint goals.
1.2 PROPOSED REMEDIATION ENDPOINTS
The primary remediation endpoints will be the reduction of residual hydrocarbons in
unsaturated soils, and reduction and containment of DPHs to levels which can
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substantiate a variance request (North Carolina Administrative Code T15A:2t_.0106 and
0113). The variance request will be made after a sustained effort has been made to
rernediate the petroleum hydrocarbons in the subsurface at the site. After the data trends
show an asymptotic decline in ground water concentrations, a variance request for
cleanup to concentrations other than drinking water standards will be submitted to DEM
for review under the provisions of T15A:2L:.0106 (e) and (f).
2.0 BACKGROUND
2.1 SITE DESCRIPTION
The site is located in south Hickory, North Carolina, in a primarily rural residential area.
Immediately upgradient of the site to the east is a Wilco gasoline station which has an
active petroleum storage tank facility. To the south of the site, across Highway 127, are
residences. To the southwest of the site across HWY 127, is a Quality Gasoline outlet,
which has an active petroleum storage facility. To the west of the site is an open gravel
area for parking, and to the north is farm land. The topographic map of the area
surrounding the site is presented as Figure 1.
The general site plan is presented as Figure 2. There are presently six (6) monitor wells
on site, and four (4) monitor wells located on adjacent properties. There are presently
no recovery wells at the site, although there is subsurface vapor extraction piping in place
around the former tank system. Utilities located on the site include a potable drinking
water well, service station product lines, and subsurface and overhead power lines. There
are four (4) monitor well immediately adjacent to the site surrounding the Wilco tanks.
2.2 PREVIOUS INVESTIGATION RESULTS
The Comprehensive Site Assessment (CSA) was conducted by Southeastern Geological
Services (SGS) during 1992. The site assessment describes the geology of the site,
hydrogeology, well installation procedures, areal and vertical extent of hydrocarbons, and
sensitive receptors in the area. The assessment was approved by the NCDEHNR in late
1992. The findings of the earlier investigation are summarized as follows :
2

The suspected source of hydrocarbons is the former UST system.
Potential receptors in the area are outlined in the CSA, and include several potable
wells within 1/2 mile of the site (potable wells shown on Figure 3).
The Geology of the site is saprolitic soils over most of the site with some bedrock
at surface on the northern part of the site.
The saprolitic soils at the site consist generally of varicolored clayey silts.
The bedrock/saprolite interface appears to consist of varicolored silty sands
The bedrock consists of amphibolite and granitic gneiss. Foliations are reported
to be approximately horizontal..
The surficial aquifer is contained within the saprolite and uppermost fractured
bedrock. This surficial aquifer will be the primary target of the site remediation
efforts. Cross sections are provided as Figures 4 through Figure 8.
The interaction of the water table with bedrock seems to be irregular, however, for
the purposes of the remediation, Handex has considered the saprolite to be
interconnected by fractures with the upper bedrock for modeling and recovery
purposes. Figure ,9 and 10 show the latest water table contour maps.
The ground water recovery will need to affect the surficial water in the saprolite,
and the upper bedrock.
The average water table gradient from the CSA is reported as 0.035.
The average of the hydraulic conductivities presented in the CSA is 0.67 ft/day.
The average transmissivity value presented in the CSA is 3.70 ft2 /day. Handex
recalculated the transmissivity to better approximate interconnected flow in the
upper bedrock and saprolite.
The average horizontal velocity presented in the CSA is 0.16 feet per day.
The CSA reports that approximately 550 cubic yards of contaminated soils remain.
The areal extent of the hydrocarbons has been assessed by the present well array.
The CSA describes the ground water contamination as extending vertically to
approximately 69 feet below land surface (BLS). The vertical extent of
hydrocarbons indicates that the hydrocarbons are migrating into the upper
fractured bedrock.
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2.2.1 Ground Water Quality Assessment
The areal distribution of dissolved hydrocarbons was assessed by collecting ground water
samples from the shallow wells located surrounding and within the containment dike. The
results of the ground water analyses are summarized on Table 1, and show the chemical
analyses from two sampling events, The highest benzene concentrations are present in
MW-1 which penetrates the former tank basin and MW-3 and MW-4 located downgradient
of the former tank basin, The highest benzene, toluene, ethylbenzene, and xylenes
(BTEX) concentrations are present in MW-1 which penetrates the former tank basin and
MW-3 and MW-4 located downgradient of the former tank basin. The results of the
perimeter well sampling showed no detectable concentrations of MTBE or BTEX. Figure
11 is a benzene concentration contour map, and Figure 12 is the Methyl Tertiary Butyl
Ether (MTBE) concentration contour from the prior report. The BTEX concentration
contour map which shows the latest results from each of the monitor wells is presented
as Figure 13.
The vertical extent of hydrocarbons has been assessed using monitor well MW-5. The
detected concentrations of hydrocarbons in MW-5 were below laboratory detection limits.
The vertical extent of petroleum hydrocarbons has been assessed to an adequate degree
for the present time.
2.2.2 Soil Quality Assessment
Soil quality was assessed using chemical and vapor analyses over the study area,
Chemical analysis of soil showed the detection of concentrations of petroleum
hydrocarbons and total petroleum hydrocarbons (TPH). The locations where the soils
displayed the highest vapor and laboratory concentrations in the soil were near MW-1.
The soil vapor readings for each sample collected are presented on Table 2. The results
of the soil assessment indicate the soils in these areas of the site will require remediation.
These areas will be addressed in the corrective action plan.
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2.2.3 Water Table Contour
In the assessment report, the water table contour map indicated ground water flow to the
southwest on the ridge top, and thence to the southeast and northwest on the ridge
flanks. This seems likely given the topographic position of the site. The final ground
water contour (unrestricted flow) is presented as Figure 9. The direction of ground water
flow is variable across the site due to the topography and presence of bedrock near
surface. The site can best be described as ground water flow in a saddle with flow along
the ridge at the crest and downhill along the flanks of the ridge. The gradient used for
the remediation planning was along the ridge from the area near MW-1 toward the new
tank field. The gradient measured in this direction was determined to be an average
gradient of 0.05. The annual water table fluctuations range from 1 to 4 feet.
2.2.4 Potential Receptors
The sensitive receptors in the area are detailed in the prior assessment report. The land
use surrounding the site is primarily residential, rural farming, and small businesses.
There are two other gasoline stations adjacent to the property, a Wilco to the northeast
of the site with a tankfield adjacent to Bob's Food Mart property line, and a Quality Gas
across Highway 127, to the south of the site. There are 10 potable wells within a 1/2 mile
radius of the site, one of which is the potable well at Bob's Food Mart. These potable
wells are typically installed to a depth of over 150 feet to recover water from the lower
bedrock aquifer. The focus of the remedial action is to prevent further downgradient
migration of petroleum hydrocarbons in the surficial water table zone, and recover
hydrocarbons which have migrated vertically into the upper fractured bedrock aquifer.
2.3 SITE GEOLOGY AND HYDROGEOLOGY
Soil borings and monitor wells were used to characterize the uppermost saprolite zone
which contains petroleum hydrocarbons. The earlier soil borings reported weathered -
amphibolite and granitic gneiss bedrock was encountered between 38 and 50 feet below
land surface (BLS). The average depth to competent bedrock is approximately 38 feet.
The Geology of the site is saprolitic soils over most of the site with some bedrock at
ndex*

surface on the northern part of the site. The saprolitic soils at the site consist generally
of varicolored clayey silts. The bedrock/saprolite interface appears to consist of
varicolored silty sands atop fractured bedrock. The bedrock consists of amphibolite and
granitic gneiss. Foliations are reported to be approximately horizontal.
The surficial aquifer is contained within the saprolite and uppermost fractured bedrock.
This surficial aquifer will be the primary target of the site remediation efforts. Cross
sections are provided as Figures 4 through Figure 8. The interaction of the water table
with bedrock seems to be irregular, however, for the purposes of the remediation, Handex
has considered the saprolite to be interconnected by fractures with the upper bedrock for
modeling and recovery purposes. Figure 9 and 10 show the latest water table contour
maps. The ground water recovery will need to affect the surficial water in the saprolite,
and the upper bedrock. The average water table gradient from the CSA is reported as
0.035.
The average of the hydraulic conductivities presented in the CSA is 0.67 ft/day. The
average transmissivity value presented in the CSA is 3.70 ft2 /day. Handex recalculated
the transmissivity to better approximate interconnected flow in the upper bedrock and
saprolite. The average horizontal velocity presented in the CSA is 0.16 feet per day. The
CSA describes the ground water contamination as extending vertically to approximately
69 feet below land surface (BLS). The vertical extent of hydrocarbons indicates that the
hydrocarbons are migrating into the upper fractured bedrock.
The saprolite is the primary zone containing petroleum hydrocarbons and is the focus of
the assessment and remediation efforts. For purposes of remediation, Handex will focus
on the surficial zones of the uppermost 40 feet of the water bearing saprolite unit, and will
address most of the remedial efforts to that area.
6
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3.0 CORRECTIVE ACTIONS COMPLETED OR IN PROGRESS
The soil remediation efforts conducted during the underground storage tank removal
reportedly removed approximately 500 cubic yards of soil which was landfarmed on an
adjacent parcel of land., There have been no ground water remediation efforts
documented at the site to date. The release of petroleum hydrocarbons is suspected to
come from the prior UST system, which was removed in January, 1992. There have been
no liquid -phase hydrocarbons identified in any of the wells at the site. The present plume
geometry appears to be stabilized and is slowly moving toward the flanks of the ridge to
the north west and southwest of the site.
4.0 CAP AQUIFER ANALYSIS
4.1 EXPECTED AQUIFER CHARACTERISTICS
The aquifer testing conducted at the site consisted of three bail tests reported in the GSA.
The results of the testing were used in the preparation of a particle tracking model to
assess whether the proposed recovery operation was adequate to address the petroleum
hydrocarbons in the subsurface. The aquifer thickness was of great concern in the
preparation of the model. Dissolved hydrocarbon concentrations were detected in the
deep well (MW-5) borehole samples at a depth of 40 feet below the water table. These
concentrations must have migrated through fractures in the bedrock an show some
interconnected fractures do exist. The recovery of hydrocarbons from these fractures will
be greatly dependent on the location of the recovery wells to allow interaction with the
bedrock fracture system.
4.2 GROUND WATER MODELING
From the basic aquifer parameters presented in the OSA, the calculated zones of
influence of pumping wells were modeled using a particle tracking model developed and
released by the US Environmental Protection Agency (EPA). The input data, calculations,
and explanations of the model parameters are presented in Appendix B.
7
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The aquifer parameters used in the model are summarized in Appendix B. Three model
runs were conducted, all under vacuum enhanced pumping conditions. Each figure
shows the particle tracking for the capture zone of the wells used in the model over a one
_ -
year period. The actual flow rate from each vacuum enhanced pumping well will vary
based on the bedrock fractures encountered when drilling the wells. The flow rate will be
somewhat dependent on the bedrock fractures encountered and the production of water
from each fracture.
The initial modeling run was to see if pumping under non -vacuum enhanced conditions
would provide plume capture. The results of the analysis did not look favorable. The
second modeling runs were predicted using vacuum enhanced ground water recovery.
Vacuum enhanced ground water recovery is achieved by applying a vacuum of up to 20
inches of mercury to the pumping well. This provides increased flow from the well in tight
formations without a corresponding decrease in pumping elevation. The transmissivity
of the aquifer and hydraulic conductivity do not change with vacuum enhancement,
however, the equivalent drawdown in the recovery wells will be greater with vacuum
application than under atmospheric conditions. The predicted results of vacuum
enhanced pumping are presented on Table 3.
To show capture at different flow rates, Handex prepared three model runs, one at 1
gallon per minute (GPM) per well, one at 2.0 GPM, and one at 3.5 GPM. The model
results for pumping under vacuum enhanced conditions are shown on Figures 14, 15,
and 16. The 1 GPM scenario does not show coverage of the entire hydrocarbon affected
area after one year. The 2 GPM scenario provides a good approximation of plume
capture after one year, and the 3.5 GPM model shows total plume capture after one year
of recovery. The input data and graphical representation of the recovery capture zones
are presented in Appendix B. The capture zones will also provide capture of
hydrocarbons present in the vadose zone soils near the former tank system. This will
provide recovery of hydrocarbons from soil required for soil cleanup.
8
m•••••=1.1
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5.0 REMEDIAL ACTION ALTERNATIVES EVALUATION
5.1 SOIL REME©IATION ALTERNATIVES
The selection of a sail remediation technology depends on the extent of contamination,
the geologic setting, the risk of sensitive receptors, the established remediation endpoints
and the ability of the technology to achieve those endpoints. The degree of residual
petroleum hydrocarbons detected by soil analyses coincides with the dissolved
hydrocarbon plume. Hydrocarbons in soil are usually evidenced in the residual and vapor
phase from the liquid -phase hydrocarbons passing through soils; the liquid phase can
also be present in the soil column. In any event, it is imperative that impacted soils be
addressed to eliminate a potential source of continuing ground water contamination. To
do so, remedial technologies are evaluated with respect to the site conditions. A brief
overview of how each technology can be applied is also provided.
5.1.1 Excavation and Treatment of Soil
Excavation of impacted soils may be a practical approach, particularly if the extent of soil
contamination is limited. At Bob's Food Mart, 550 cubic yards of contaminated soil have
already been excavated for treatment. Any further excavation of contaminated soils would
not be practical due to the impact to the canopy and pump island areas, The soil volume
that requires treatment is not large, however, the soil can be treated effectively in place
using the proposed remediation system more cost effectively.
5.1.2 Soil Vapor Extraction
Impacted soils can be remediated through in -situ volatilization or soil vapor extraction,
depending on the permeability of the soils. This technique works well with highly volatile
compounds, such as gasoline, in permeable substrates. It does not necessarily work well
with heavier hydrocarbon mixtures such as diesels, waste oils, or fuel oils, and its
influence can be effective, yet limited, in low permeability soils. In -situ volatilization
involves removal of volatile hydrocarbon compounds from the soils using forced or drawn
air currents. This may be augmented by injection of air or steam in conjunction with
extraction.
9

Extraction can be accomplished using various size and types of blowers, such as
regenerative blowers or high -vacuum low flow pumps; the selection of blower type is
strictly dependent on the permeability of the subsurface and the desired radius of
influence.
Once extracted, vapors may need to be treated depending on air emission regulations.
After the concentration and flow rates are established, Handex will evaluate air dispersion
modeling at the site first. If the modeling shows that the soil vapors will not meet the air
quality discharge criteria for Mecklenburg County, the most appropriate off -gas treatment
system will be selected. Possible off -gas treatment systems to be evaluated are
+� Vapor -Phase Carbon Treatment
Catalytic Oxidation
Thermal Oxidation
+ Regenerative Thermal and Catalytic Oxidation
Biological Soil -Vapor Treatment
These potential off -gas treatment systems will be evaluated with respect to air discharge
permit considerations, facility operations, predicted vapor treatment system longevity, and
cost effectiveness.
5.1.3 Recommended Soil Remediation Method
The preferred soil remediation method is to extract vapors from the vadose zone from the
recovery wells using a liquid -ring pump. The liquid ring pump maintains high vacuum
between 15 and 20 inches of mercury at 10 to 20 cubic feet per minute (CFM) on each
recovery well. The air recovered from this extraction will be sampled to determine the
concentration of hydrocarbons present in the off -gas stream. If the concentrations are
Tess than 40 pounds per day, then there should be no air discharge permit necessary.
The source will have to be registered with DEM. If the from soil -vapor extraction system
exceeds the 40 pound per day limit, then temporary air treat will be proposed. The air
treatment system will be selected at a later date after a full scale pilot test is conducted
on the entire extraction well array. This will provide accurate concentration data and air
10
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flow rates to decide if off -gas treatment is necessary, and to allow for the sizing of the
treatment unit.
The analysis of Vacuum Enhanced pumping test data from other sites with similar
subsurface conditions shows that the air -flow capacity of the saprolite is very low,
although the ability to sustain a vacuum is very high. This means that the ability for the
soil to exchange air through interconnected pore space within the soil will occur at a
relatively slow rate. The soil remediation might be enhanced by pneumatic fracturing and
the addition of air inlet wells installed in strategic location around the site to increase air
volume and air flow through the soil. This would translate to a greater air flow rate
through the soil and should remediate the soil in a shorter period of time. Handex
proposes to pneumatically fracture the soils to enhance the recovery of vapors from the
vadose zone and to install air inlet pipes at the boundaries of the contaminated area to
allow passive inflow of fresh air into the subsurface. The air inlets are designed to allow
oxygen to enter the formation and increase the effectiveness of the vapor extraction and
enhance natural biodegradation of hydrocarbons in the soil. This soil remediation is the
most effective and technologically sound approach investigated.
5.2 GROUND WATER / LPH REMEDIAL ALTERNATIVES
As with soil contamination, remedial technologies concerning ground water are dependent
on extent and type of contamination, hydrogeollogic settings, and risk exposure to
sensitive receptors. Hydrocarbon impacts to the ground water are usually in the form of
liquid phase and/or dissolved phase hydrocarbons. Several approaches apply to
remediating this type of subsurface contamination.
Trenching Containment
• Liquid -Phase Hydrocarbons (LPH) Recovery
• Ground Water Extraction and Treatment
The most appropriate and cost effective method of recovery and containment of ground
water is to pump ground water under vacuum enhanced conditions using submersible
pumping equipment.
11
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Air sparging was investigated from literature, as a stand-alone treatment method. Air
sparging is usually well suited for sandy of granular soil media, and is not well suited to
remediation of large plumes in saprolite. Additionally air sparging has a tendency to drive
water and LPH away from the sparge point. For this reason, air sparging is not as well
suited for containment of hydrocarbons at the site as vacuum enhanced pump and
treatment, Air sparging alone cannot effectively achieve downgradient capture of
hydrocarbons, and address the site cleanup.
5.3 GROUND WATER EXTRACTION METHODS
Handex evaluated the following pumping methods for ground water pumping at the site.
• Total Fluids Pumping - At the site, Handex proposes to use pneumatic pumping
equipment to recover total fluids from the subsurface. This selection is made
based on the depth to fluids in the subsurface, desired flow rate, and desired area
of influence. These pumps minimize emulsification of the liquid -phase
hydrocarbons such that separation can be achieved with a minimum of retention
time in the separator.
• Dual Phase Pumping -- Dual phase pumping involves using a dual punp, system
within one recovery well or the recovery trench well to recover ground water and
liquid -phase hydrocarbons (LPH) separately. The lower pump of a dual pump
system is used to lower the water table to recover dissolved hydrocarbons and
create a cone of depression to induce liquid -phase hydrocarbon flow into the
recovery well. The upper pump is then used to only recover the liquid phase that
enters the well. This system will not be employed at the site due to the additional
cost and the limited thickness of LPH.
+ Vacuum Enhanced/Total Fluids Extraction - Pumping ground water or total
fluids can often be enhanced by applying a vacuum to the subsurface at the paint
of fluid removal. Vapor extraction and pumping augment each other in that
application of the negative pressure effectively creates a stronger hydraulic
gradient toward the recovery point and accelerates contaminant and ground water
flow toward the extraction point. This in turn increases the contaminant recovery
12

rate and recovery well yield. In the addition, pumping ground water or total fluids
draws down the water table and exposes soils that may also be impacted. This
allows for recovery of residual and vapor -phase hydrocarbons in the soils.
5.3.1 Vacuum Enhanced Ground Water Pump and Treatment
The use of vacuum enhanced ground water and LPH recovery has been applied to
petroleum sites with low hydraulic conductivities to increase the effective capture zone,
increase the pumping rate, and enhance soil cleanup. The procedure includes using a
submersible pump to provide direct ground water and LPH recovery by pumping, and
simultaneously recover soil vapors from the same well at high vacuum, up to 25'' of
mercury (Hg). The vacuum enhancement increases the well yield by as much as 250 %,
and provides enhanced recovery of liquid -phase hydrocarbons from the soil and capillary
fringe.
The bail test data yielded aquifer hydraulic conductivity data which was used with the
predictable vacuum enhancement to obtain the equivalent drawdown for the proposed
recovery wells. No vacuum enhanced pumping test was conducted on the site, however,
Handex has experience in vacuum enhanced ground water recovery in tight saprolftic
soils and has demonstrated an increase in the pumping rate of over 250 %. This
remedial method would also provide soil treatment which would greatly reduce the life of
the recovery and treatment project, and therefore the overall project cost.
5.4 RECOMMENDED REMEDIAL OPTION
The preferred soil and ground water remediation method is to extract vapors from the
vadose zone from the recovery wells using a liquid -ring pump which maintains high
vacuum (up to 20 inches of mercury) on the recovery well and pump total fluids using
submersible pumps. The conceptual remediation plan for the proposed system is
presented as Figure 17. Table 4 presents the projected timeline for the remediation at the
site. The remedial option selected was based on overall effectiveness, initial cost, long
term operation costs, reliability, and estimated time to cleanup.
13

6.0 SOIL REMEDIATION DESIGN
The remediation of soil containing hydrocarbons will be accomplished by extracting soil
vapors from the subsurface using a liquid -ring pump. This technology has been tested
in similar soils and produced a large radius of influence. The following sections describe
the soil remediation process and design.
6.1 DESIGN OF SOIL -VAPOR EXTRACTION SYSTEM
The ground water recovery/vapor extraction well array proposed for the site is shown on
Figure 18. This well array was designed using the radius of influence inferred from vapor
extraction feasibility tests conducted in saprolite of similar composition at another site.
The vapor extraction well array will be composed of wells designed for ground water and
vapor extraction.
The ground water/vapor extraction wells will be connected to the liquid -ring pump by
solvent welded PVC piping installed in a subsurface trench from each well, and joined to
a manifold pipe near the liquid -ring pump. A valve will be installed at each well head to
tnrottle or shut-off the system as necessary. Subsurface piping from the extraction wells
to the liquid -ring pump will be accomplished with the least disturbance of the existing site
features possible, along with the ground -water piping. The general piping layout diagram
is also presented on Figure 18.
The total air flow extracted from the subsurface is expected to be approximately 8-10
cubic feet per minute (CFM) per well using 2 recovery wells. The proposed soil -vapor
extraction is predicted to yield approximately less than 30 CFM from the entire recovery
system. The liquid -ring pump requirements are that it provide 20 inches of vacuum
measured in mercury at each of the 2 ground water and vapor extraction points at an
extraction rate of approximately 10 to 15 CFM per well. In addition to the two recovery
wells, it may be possible to extract hydrocarbon vapors from the existing vapor extraction
piping installed during the tank replacement activities. It is not anticipated that the soil
vapor extraction system will sustain volatile organic emissions greater than 40 pounds per
14
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day. After the pilot testing of the system, the level of discharge will be evaluated with.
respect to the discharge standard, and off -gas treatment will be proposed if necessary.
7.0 GROUND WATER LPH RECOVERY DESIGN
7.1 RECOMMENDED GROUND WATER RECOVERY SYSTEM
To accomplish ground water cleanup objectives, ground water is pumped to create a
cone of depression in the water -table near the hydrocarbon source. This reduces the
hydraulic head in the surficial aquifer, causing the ground water containing dissolved
hydrocarbons to migrate toward the recovery well. The recovery of dissolved
hydrocarbons is based on the recovery of ground water, therefore, hydraulic control of
the dissolved hydrocarbon plume must be demonstrated.
The ground water recovery system recommended for the site consists of pumping total
fluids from two (2} recovery wells as shown on Figure 18. The recovery well detail is
presented as Figure 19. This recovery scenario is predicted to produce an average flow
of 1,0 to 3.5 GPM from each extraction well, for an average flow of 2.0 to 7 GPM from the
entire recovery system. The pumping equipment to be used in the recovery wells will
consist of electric submersible pumps which will be capable of over 10 GPM sustained
pumping.
7.2 RECOVERY WELL DESIGN
The proposed recovery well array consists of two (2) new recovery wells installed to a
depth of 60 feet below land surface (BLS). The proposed recovery wells will consist of
approximately 50 feet of 6-inch diameter, 0.020 inch slotted, schedule 40 PVC, well
screen, set with 30 feet below the static water level and 20 feet above the static water
table. The wells will contain at least 10 feet of solid well casing above the screen to
provide a good surface seal for vacuum enhanced recovery. The proposed recovery
wells will be constructed of 6-inch diameter well casing and screen to allow for the
installation of pumping equipment and operational considerations. The details of the
recovery wells are shown on Figure 19.
15
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7.3 GROUND WATER PIPING DESIGN
The subsurface ground water recovery piping will be constructed of PVC since the
recovery is not anticipated to encounter any separate phase hydrocarbons, The
conceptual recovery piping layout is shown as Figure 18. The pumping equipment
selected will be capable of developing sufficient head to overcome the piping system
friction losses and will be capable of delivering more than the required maximum flow rate
of 3.5 gallons per minute (GPM) per well to the treatment system.
Subsurface piping and electrical lines will be installed in one subsurface trench connecting
the recovery wells and the treatment system. The PVC lines for vacuum enhancement
will also be installed in the same trenches as the ground water piping. To regulate flow
through the system, a shut-off/throttling valve, flow meter, and sampling port will be
installed at each recovery wells and sampling ports and valves will be provided at each
of the treatment system units.
7.4 GROUND WATER PUMP DESIGN
The pumps required to pump ground water at a rate of between 0.5 and 5.0 GPM from
each of the wells are electric submersible pumps. This type of pump is useful in pumping
where separate -phase hydrocarbons (SPH) is not anticipated. The use of electric
submersibles should not effect the operation of the oil/water separator. The pump
intakes will be set at approximately 15 feet below the static water levels. The pumps will
be equipped with a check -valve to prevent back -flow of water from the treatment system
when the pump is shut down. The pumps will be wired directly to the control box.
7.5 TOTAL EXPECTED WATER FOR TREATMENT
The normal predicted flow rate required for hydrocarbon recovery is 2.5 gallons per
minute (GPM) per well, with a maximum flow per well estimated at 3.5 GPM per well.
Since there are two proposed wells pumping at 2.5 GPM, the average flow for the site
would be approximately 5.0 GPM. Under peak flow conditions, the treatment system
would have to effectively treat 3.5 GPM per well, or a total of 7.0 gallons per minute.
16
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Since the pumping units will be set at a specific flow rate, the treatment system will not
be affected by significant rainfall events and subsequent infiltration. The treatment and
piping systems will be specified at 10 gallons per minute to allow for excess system
capacity. The peak flow specifications are particularly important for the piping, oil/water
separator, air stripper and the carbon treatment unit.
8.0 GROUND WATER TREATMENT SYSTEM DESIGN
8.1 RECOMMENDED GROUND WATER TREATMENT SYSTEM
The recommended ground -water treatment system for the site was chosen with the
General NPDES discharge for cleanup of petroleum sites in mind. The General NPDES
permit requires the treatment system to be configured with a phase separation oil/water
separator, an aeration unit as primary treatment, and a carbon polishing unit prior to
discharge. This system is shown on the conceptual process flow diagram presented on
Figure 17. If the general NPDES discharge permit is not obtained, then alterations of the
treatment system may be made.
The process schematic shows the oil/water separator for the recovered ground water at
the site. The recovered ground water is pumped from the separator for treatment through
the low profile air stripper, then flows through a particulate filter prior to final polishing in
the carbon adsorption unit. The water will be treated through the remediation system and
discharged through the general NPDES permit for petroleum remediation sites. The
treatment units required to accomplish the cleanup objectives are described in the
following sections.
The ground -water treatment systems will be enclosed in a building to protect it from the
elements and freezing. Signed and sealed as -built drawings of the treatment system will
be provided after the system is installed.
17
andcx'

8.2 OIL WATER SEPARATOR
The first step in the treatment system is the separation of the LPH and dissolved phases
of hydrocarbons. The oil/water separator selected for the site has a 100 gallon capacity,
coalescing packed media, and is rated at a normal flow rate of 10 gallons per minute.
This should be able to accomplish phase separation even at the maximum predicted flow
rate for the system. The peak flow for the system may be increased due to significant
rainfall events and subsequent infiltration. The specifications and details of the oil water
separator/air stripper are presented in Appendix C. Liquid -phase hydrocarbons have not
been identified in any of the monitor wells, however, some may be encountered after
start-up. The oil/water separator is required as a treatment process element to meet the
requirements of the NPDES General Permit for petroleum contaminated ground water
remediation.
8.3 LPH HOLDING TANK DESIGN
The oil water separator will automatically discharge LPH to a product holding tank or
drum located near the treatment system. The holding tank will be fitted with a high level
shut-off switch which will shut down the recovery systems if the tank is full. This fail-safe
will assure that no LPH discharge occurs. The tank will be managed in such a way that
the tank is periodically emptied of LPH prior the automatic system shut-off being
activated.
8.4 DESIGN OF PRIMARY TREATMENT AIR STRIPPING
The low -profile air stripper treatment system will receive the water from the ground water
recovery wells for primary treatment using aeration. The recovery water will be treated
through the oil -water separator and flow into the low profile air stripper. The treatment
system selected for the facility consists of an ejector systems "Stripperator" which
includes a low profile air stripper. This aeration unit consists of a single baffled tray
connected to a sump through which high volumes of air are forced using a blower. The
process is very efficient for removal of volatile organic compounds usually associated with
ground water cleanups at petroleum sites. The summary of cleanup standards and
18
ndexm

discharge criteria are presented on Table 5, Concentrations of MTBE are expected in the
treatment system and should be primarily removed from the water using aeration.
The low -profile air stripper has been designed for a normal flow rate of 5 gallon per
minute (GPM), however, it is capable of treating water at up to 10 GPM. The air stripper
will be located in the treatment compound shown on Figure 17. The low profile air
stripper will be fitted with an exhaust stack at the top of the unit, a single aeration tray,
a sump at the bottom of the unit, a high level switch to shut off the recovery system
should the air stripper become flooded, access ports for cleaning, an effluent sampling
port, and a sight glass for the sump. The electric blower accompanying the low -profile
unit will force air into the treatment unit. The controls for the unit will be included as
needed.
The water treatment parameters used for the air stripper design were taken from the
monitor wells displaying the highest BTEX concentrations. The most significant
concentrations were MTBE and benzene which were the limiting factors in the design.
The results of the recovery well average water concentrations for two proposed recovery
wells are presented on Table 6. These average concentrations were used to prepare the
air stripper design presented in Appendix C. These calculations show that the selected
air stripper has sufficient capacity to treat the average reported BTEX and MTBE
concentrations from the recovery wells.
A particulate filter will be installed between the air stripper and the carbon unit to remove
particulate matter and lengthen the time between backflushing and carbon changes.
8.5 DESIGN OF SECONDARY TREATMENT : CARBON ADSORPTION UNIT
The secondary treatment system will consist of a granular activated carbon adsorption
(GALA) unit. This process will assure that any hydrocarbons not removed from the
wastewater stream by aeration will be adsorbed prior to waste water discharge to the
NPDES outfall. The GALA unit will consist of one 24' diameter carbon unit which contains
19
andcxe

400 pounds of activated carbon for ground water treatment. The carbon bed life
expectancy of this unit is a minimum of one year, depending on particulate matter in the
treated water, and may be as much as two years. The carbon treatment unit will be
capable of backwashing the carbon to remove particulates, and extend the carbon bed
life.
A particulate filter will be installed in -line between the air stripper and the carbon
adsorption unit to remove solids. This should greatly extend the carbon bed life and limit
carbon replacements. The GACA, in this application as a polishing unit, will receive
limited volatile and semi volatile hydrocarbons which should easily be treated.
8.7 PRETREATMENT for IRON, LEAD (Pb), and BIOFOULING
Characterization of ground water samples for water chemistry parameters other than
BTEX and MTBE have not been performed, These parameters are anticipated to have
an effect on the overall maintenance of he recovery and treatment systems, however, the
effects should be minimized by regular maintenance of the system. These parameters
were evaluated in the preparation of the treatment system design. Pre-treatment for lead
(Pb) is not anticipated. Iron and biofouling of the treatment system has been considered
in the maintenance schedule for the site. The primary treatment system will aerate and
precipitate iron. The removal of iron and biofouling on the aeration trays will be done
monthly with periodic maintenance, or as needed, Any iron sludges created in the air
stripper will be removed from the sump, tested for toxicity, and disposed of as necessary.
The primary treatment system will aerate and precipitate iron. The removal of 'iron and
biofouling on the aeration trays will be done monthly with periodic maintenance, or as
needed. Should iron fouling of the aeration unit be a problem, a sequestering agent will
be placed in line to inhibit iron fouling.
20
nde

8.6 SYSTEM CONTROLS and SAFETY MECHANISMS
The recovery and treatment system safety controls would consist of high level shut-off
switches in the oiliwater separator, water sump, LPH holding tank, and wet -well. An air
stripper blower failure switch will turn off the electric submersible pumps at the breaker
box.
8.8 GROUND WATER DISPOSAL SYSTEM
Handex has reviewed the options for disposal of treated ground water at the site. The
possible options considered were:
• Infiltration of treated ground water
• Discharge of treated water to sanitary sewer
• Discharge of treated water to surface water using NPDES General Permit
No. NCG510000, for "Petroleum Contaminated Groundwater Remediation
and Similar Discharges"
The proposed pumping rate of the recovery system will create a normal flow rate of 4 to
7 gallons per minute for disposal. Infiltration of this water would be difficult at this flow
rate without a large infiltration gallery. There are fouling problems and maintenance of
infiltration galleries which are operational concerns. The other disposal options offer a
better solution to the problem.
Disposal of treated water to the sanitary sewer was considered as an option. At the
present time, the sanitary sewer system is available along Highway 127. The costs of
disposal to the sewer in monthly volume charges and analytical fees would be greater
than disposal of water through a NPDES general permit.
From the cost analysis, the best option is to discharge treated ground water to the
General NPDES Permit. The engineering report will be used to apply for a general
NPDES permit to discharge treated ground water for the site. The treatment system
effluent water -quality objectives will be the same as the criteria listed in the NPDES
General Permit No. NCG510000 "Petroleum Contaminated Groundwater Remediation and
Similar Discharges". These NPDES general permit discharge criteria and monitoring
21

requirements are listed on the Table 7. The actual disposal piping will be four -inch
diameter Schedule-40 PVC pipe which will discharge from the system to the ditch along
the mutual property boundary with Wilco. The water will flow by gravity and no pumping
equipment will be required. The proposed discharge location is shown on Figure 18,
8.9 TREATMENT SYSTEM EFFLUENT WATER QUALITY OBJECTIVES
The treatment system effluent water -quality objectives will be the same as the criteria
listed in the NPDES General Permit No. NCG510000, "Petroleum Contaminated
Groundwater Remediation and Similar Discharges". These NPDES general permit
discharge criteria and monitoring requirements are listed on the Table 7, Since the
ground water would not meet the discharge criteria without treatment, treatment is
proposed. The treatment system is designed to meet the treatment system component
requirements of the NPDES general permit, and the effluent water quality requirements
as well. If system monitoring shows that the treatment system has failed to reduce
hydrocarbon concentrations within these goals, the NCDEM office administering the
General NPDES permit will be notified within 24 hours, or on the next working dayL
Details of such incidents and their resolution will be included in the tri-annual reports,
9.0 DISPOSAL OF RECOVERED LPH
Recovered liquid -phase hydrocarbons (LPH) will be disposed of in accordance with
applicable local, State, and Federal laws. No substantial amounts of LPH are anticipated
at this site.
10.0 PERATION AND MAINTENANCE
The operation and maintenance of the proposed system will consist of many tasks
relating to the vapor recovery, pumping, treatment, and disposal systems and equipment
at the site. A brief synopsis of the planned operation and maintenance schedule are
listed in the following sections.
22
andexe

10.1 GAUGING AND BAILING OF WELLS
Ground water and LPH levels will be measured in each well monthly, and ground -water
contour maps prepared using these data. This data will help remediation tracking and
show the development of the cone of influence around each extraction point. The results
of these activities will be summarized in the tri-annual reports presented to DEM.
10.2 RECOVERY SYSTEMS MONITORING
The recovery wells and trench will be examined at each scheduled operation and
maintenance site visit to determine whether adjustments are needed. Flow and pump
intake levels will be adjusted as specified by the project manager. The total flow from
ground water recovery system will be checked, as well as flow from the water holding
tanks and product sump. The pumping of the recovery trench will be adjusted as
necessary to maintain proper flow in this area.
10.3 TREATMENT EQUIPMENT MONITORING
The treatment system is designed to function with a minimum of operation and
maintenance. During maintenance visits, Handex will check the system for proper
operation of the oil/water separator, check the air stripper for fouling and clean as
necessary, check the carbon unit for excessive pressure and back -flush as necessary,
and inspect and adjust the vapor treatment equipment. System controls will be adjusted
as necessary. Sampling of the system will consist of
1) Monitoring of the hydrocarbon concentrations in the recovery system
influent, air stripper effluent, and carbon treatment system effluent. Influent
and effluent water samples collected monthly will be analyzed in accordance
with the General NPDES permit to verify treatment efficiency. These
analyses will be conducted the first two weeks, and monthly thereafter.
2) Collecting air quality samples of the soil -vapor extraction system periodically
to assess concentration changes with time. Minimum frequency Quarterly
the first year and annually thereafter.
During the weekly checks, maintenance of the syster
maintain system efficiency and maximize operational
general inspection.
23
ill be performed as necessary to
e and the system will be given a
andcx°

11.0 REMEDIATION SYSTEtI MONITORING AND REPORTING
The reports required for the remediation tracking are (1) monthly discharge monitoring
reports, (2) tri-annual remediation progress reports, and (3) client reports. These reports
summarize the appropriate information collected about the remediation system,
recommend changes to the system, and draw conclusions about the overall effectiveness
of the system to achieve remediation goals.
11.1 DISCHARGE MONITORING REPORTS
The discharge monitoring reports are required on a monthly basis for the General NPDES
discharge permit proposed for the site. These reports will contain effluent quality data,
flow data, and site information. The General NPDES discharge will be routed to the
intermittent stream west of the site. If system monitoring shows that the treatment system
has failed to reduce hydrocarbon concentrations within the established remediation goals,
the NCDEM will be notified within 24 hours, or on the next working day. Details of
exceedances and their resolution will be included in the tri-annual reports, however, the
system has a carbon polishing unit which should keep exceedances from occurring.
11.2 TRI-ANNUAL REPORTING
The tri-annual reports will provide tables, graphs, figures, and a written summary of the
remedial action progress. This information will be used to assess the remedial progress
during the year, and project necessary changes to increase the effectiveness or reduce
costs for the recovery, treatment, and disposal systems. It is anticipated that the first
reports will show the results of the treatment systems effectiveness, soil -vapor extraction,
LPH recovery, and ground water recovery.
11.3 WATER -QUALITY SAMPLING OF OBSERVATION WELLS
Included in the tri-annual reports will be ground water analytical data from selected
monitor wells at the site. Samples from designated wells will be analyzed for BTEX and
MTBE using EPA Method 602 (modified) tri-annually to document remediation progress.
These data will be used to track remediation progress toward the remediation goals. In
24

the oreparation of a variance request, these data will be used to demonstrate the
remediation progress made to date.
The proposed monitor wells to be sampled for BTEX analysis for the initial tri-annual
report are wells 1, 2, 3, 4, 5, 7, 8, and the two recovery wells RW-1 and RW-2. These
analyses will be used to assess changes in concentrations with time. The number of
wells to be sampled in the following tri-annual frequency may be reduced based on the
results from these wells. Chemical analyses of ground water from each of the recovery
wells will be done tri-annually to assess remediation progress. These data will be
reported in the tri-annual reports.
12.0 REMEDIATION PROGRESS EVALUATION
The cleanup objectives of the proposed corrective action are to recover LPH from the
water table and soil if present, recover soil vapors from the subsurface, recover dissolved
phase hydrocarbons from the areas identified in the assessment reports, and areas of
highest concentrations, and maintain a downgradient capture of the dissolved
hydrocarbons. The approach selected for ground water recovery and treatment should
accomplish these goals. The goals of the remedial action will to be re-examined one year
after treatment starts, and each following year.
13.0 REMEDIAL ACTION COMPLETION
After the data trends show an asymptotic decline in ground water concentrations, a
variance request for cleanup to concentrations other than drinking water standards will
be submitted to DEM for review. The variance request will request a reduction or
elimination of the ground water and soil remediation at the site based on the efforts to
date, the long term use of the property, and a basic evaluation of risk to the public if the
contaminant levels remain above drinking water standards. This variance request should
be submitted after a significant reduction of dissolved hydrocarbons in ground water has
25

been achieved. Cleanup of the silty soils at the site to drinking water standards may not
be achievable using best available technology econ u is 11 reasonable. The variance
request will provide supporting information that cleanupt drinking water standards would
produce hardship without equal or greater public benefit. The remedial action will be
deemed completed after the rian e request is i approved.
26

REFERENCES
Cedergren, H.R. (1977). See2"d ed.) NY.,NY.: John Wiley
& Sons, pp.66-76.
Driscoll, F.G. (1986). Groundwater and Wells.(2"d ed.) St. Paul, Minnesota: Johnson
Division, pp. 1-1089.
Johnson, A.I., USGS (1967). Specific Yield - Compilation of Specific Yields for Various
Materials: U.S. Geological Survey Water -Supply Paper 1662-D. Washington D.C.:
U.S. Govt. Printing Office, pp. D1-D33.
Keeling J.F. and Tsang C.F. (1983). Velocity Plots and Capture Zones of Pumping
Centers for Ground -Water Investigations, Ground Water, Volume 21, No. 6,.
November -December 1983, pp. 701-714.
North Carolina Administrative Code, Title 15, Subchapter 21.. North Carolina Department
of Health and Natural Resources, December 1989, Classification and Water quality
Standard A icable to the Ground Waters of North Carolina, Section§ .010Q,
.0200, and .0
SGS Report (January, 1991). Comprehensive Site Assessment Report (and follow-up
reports), Southeastern Geological Services, Shelby, NC, pp. 1-15.
27
andex°

In

SECTIONS IN SAP
BOB'S F ,T
CATAWBA COUNTY

FIGURE5
CROSS SECT ION --
BOB'S D =MRT
CATAWBA COUNTY'
a'

2
FIGURE 6
CROSS SECTION-
C FOOD T

TD
Fracture Zone
t Pathway
Bedrock
SCALES:
FIGURE
CROSS SECTION
BOB'S FOOD PiAFRT
T LT
00
zene

SCALES.:
HORIZ
FIGURE
CROSS SECTION T ION
FOODP\ART
CATAWBA COUNTY
benzene

ca Monitor Well
r Former Tank Basin
FIGURE 9
NON-RESTRICTIVE F
WATER TAB_E CONTOUR
AP
1"" 1QQ'
BOET5 FOOD /TART
CATAWBA COUNTY

Monitor Well
> Flow Direction
100'
Former Tank Basin
FIGURE 10
SHOWING BEDROCK INFLUENCE
WATER TABLE CONTOUR P\AP
BOB'S FOOD t\ART
CATAWBA COUNTY

1
FIGURE 1
BENZENE CONCENTRATION
BOB's FOOD fT

9
Bed
n
Bedrock:
no anafind
acquirer'
nnfidn
FIGURE 12
iv\TBE ISOEONCENTRATION
BOB'S FOOD INNART
CATAWF3A COUNTY
AP
Monito We

VACUUM WELL SEAL
FIL
al
ELECTRIC SUBMERSIBLE
PUMP
24' x 24" x 24' DEEP
SKIRTED SIE I_ PRCTTW
P ANNDLE
2' PVC SLEEVE
ELECTRIC POWER
x 2' PVC SADDLE
2" PVC VAPOR LINE
TO I hLATP ENT SYSTEPI
1' TOTAL FLUIDS LINE TO TRUNK
TO TREATPLENT SYSTEP
P I TLESS
PVC VELE CA.S I NG
6' X 4' IA I_ RalucER
ELECTRIC POWER CORD
4' D1A, 0.01 SLOT
SCE 40 PLC VF1t
SCREEN
RECOVERY WELL W/ EJECTOR T'IPE PUMP
AND VACUUM ENHANCEMENT
BOB'S FOOD MART
RHODES AND 19EALE OIL COMPANY
RECOVERY WELL DETAIL
FIGURE 19
ilandax®

TABLE
GROUND WATER QUALITY ANALYTICAL RESULTS
( SUMMARY FROM THE SGS REPORTS )
BOB -GONG
MJ
03-03-93
SAMPLE TOTAL
DATE MW # B T E X BTEX MTBE IPE
(PPB) (PPB) (PPPPB) (PPB) (PPB) (PPB
25/92
03/25/92
710 3600 30 4900 10040 860 120
53+ 174 6 14 729 14 24
9fla 190 28 176fl 3818 99
960
ND
ND
2731
ND
ND
4600
300
ND
ND
ND ND ND ND
ND ND ND ND ND ND ND
B = BENZENE
T = TOLUENE
E = ETHYLBENZENE
X = XYLENES
MTBE = METHYL TERTIARY BUTYL ETHER
IPE = ISOPROPYL ETHER

TABLE 2
SOIL QUALITY ANALYTICAL RESULTS
(SUMMARY FROM THE SGS REPORTS)
1) Excavation Samples - taken 1-8-92
SAMPLE LOCATION DEPTH TPH
(feet) (ppm)
SW-1 South Wall 15 < 6
SW-2 East Wall 15 < 6
SW-3 west Wall 15 15
SW-4 North Wall 15 11000
13-1 Center Floor 19 38000
) soil Borings 1-4 and Monitor Wells 3 & 4
Sampled 5-20 & 21-92
BORING DEPTH TPH
(feet) (PPm)
SB-1 24 < 1
SB-2 24
SB -3 25 (1
SR -4 25 (1
MW -3 30
MW -4 25 < 1
The samples were analyzed for total petroleum hydrocarbons by
EPA method 5030-

TABLE 3
PREDICTED VACUUM ENHANCED GROUND WATER FLOW
DURING PUMPING WITH VACUUM APPLIED TO RECOVERY WELLS
WELL
NUMBER
PUMPING ACTUAL
RATE / NO DRAWDOWN
VACUUM
(GPM)
R
0.5
FT)
7.0
7.0
VACUUM
APPLIED
Hg)
7.0
7.0
7.0
5„
10"
15
"
20
EQUIVALENT
DRAWDOWN
***
TT)
7.0
12.4
17.8
3.2
VACUUM
ENHANCED
PUMP/RATE
(GPM)
NA
.1 *
2.3
28.6
7.0 25 a,
34.0
2.9 *
.5
* Vacuum enhanced pumping rates estimated from test data at other sites.
*** EQUIVALENT DRAWDOWN = (1.08 x INCHES Hg) ± ACTUAL DRAWDOWN
andcx n

HANDEX
HANDEX
HANDEX
HANDEX
HANDEX
HANDEX
HANDEX
TABLE 4
Remediati©n Implementation and Evaluation Timeline
1993 thru 1997
REMEDIATION IMPLEMENTATION AND EVALUATION T[MELINE
BOB'S FOOD MART STORE
HIGHWAY 127, HICKORY, N,C,
TASK DESCRIPTION
SUBMIT CAP TO QE
APPLY FOR NPDES GENERAL PERMIT
RECEIVE COMPLETED NPDES PERMIT
ANNUAL SAMPLING OF ALL WELLS
ORDER EQUIPMENT AND INSTALL
BEG
OPE
N GROUND WATER AND SOIL REMEDIATION - STARTUP
CATION AND MAINTENANCE OF SYSTEM
FUTURE YEARS TIMELINES
TASK DESCRIPTION
HANDEX
HANDEX
HANDEX
HANDEX
AN EX
ANDEX
FILE NAME 305-'TIME
PREPARED 03-12-93
PREP, BY : Mike Jones
OPERATION AND MAINTENANCE
EPORT ON NPDES DISCHARGE MONTHLY
TRI-ANNUAL SAMPLING OF SELECTED 4" "ELLS
TRIANNUAL REPORTS OF REMEDIATION
ANNUA
ANNUA
AMPLING OF ALL WELLS
EDIATION - RECOMMEND CHANGES
UBMIT FOR VARIANCE REQUEST TO NCDEHNR
*******THE TIME TO CLEANUP IS ESTIMATED ONLY AND MAY VARY FROM WHAT IS SHOWN HERE ********

TABLE 5
SUMMARY OF CLEANUP STANDARDS AND DISCHARGE CRITERIA
GROUND
WATER
STANDARDS
COMMENTS
IMITATIONS
Remediate ground water to NC drinking
water standards listed in NCAC, Title 15,
Subchapter 2L, Section .0202, Water
Quality Standards for Class GA Waters.
SOIL
STANDARDS
Benzene = 1.0 erg/i
Toluene = 1000 pg/I
Ethylbenzene = 29 pg/l
Total Xylenes = 400 pg/I
1,2-Dichloroethane = 0.38 pg/I
Ethylene Dibromide - 0,0005 pg/I
Remediate soil to levels which do not
present a continuing source of
hydrocarbons to ground water,
(DEM action level policy guidelines)
TPH < 10 ppm = no action
TPH > 10 < 100 ppm = evaluate
TPH > 100 ppm = remediate
AIR
DISCHARGE
STANDARDS
Mecklenburg County Air Pollution Control
Permit for a petroleum contamination site,
an air discharge must not exceed the
following criteria or off -gas treatment or
dispersion modeling will be required.
Benzene < 8,1 Ibs. per year
Toluene < 98 lbs. per day
Ethylbenzene = no specific limit
Xylenes < 57 lbs. per day
NPDES
DISCHARGE
STANDARDS
The general NPDES discharge permit for
petroleum contaminated sites has
discharge monitoring requirements as
follows
KEY : ,ug/l = Micrograms per liter
TPH = Total Petroleum Hydrocarbons
ppm = Parts per million
FLOW - measured weekly
Benzene = 71,4 pg/I
Toluene = 11 pg/I
MTBE = no limit established
Lead = 25 pg/l
andcx®

TABLE 6
CONCENTRATION AVERAGES AND FLOW REQUIREMENTS
FOR AIR STRIPPER DESIGN
BOB-CONC
MJ
03-03-93
SAMPLE
DATE
03/25/92
03/2°5/92
03/25/92
03/2
92
03/25/92
03/25/92
MW #
1
2
3
4
5
6
7
8
9
10
710
530
1900
1000
ND
ND
WEIGHTED WATER CONC. AV
(MW-1 THRU MW-4 ONLY)
ND
TOTAL
T E X BTEX MTBE IPE
3600
170
190
960
ND
ND
ND
ND
1035
830
28
ND
ND
ND
ND
ND
ND
ND
ND
4900
14
1700
ND
ND
ND
700
ND
ND
10040
720
3818
ND
ND
ND
ND
ND
860
ND
ND
ND
14
4600
300
ND
ND
4327
ND
ND
ND
ND
120
24
99
ND
1444
18
ND
ND
ND
ND
ND
ND
65
NOTE
CONCENTRATION AVERAGES ARE FOR MW-1 THROUGH MW-4 ONLY

ID
TABLE 7
NPDES DISCHARGE CRITERIA
A. Effluent Limitatims and Monitoring Requirements Final NPDES Permit No. NCG510000
During the period beginning on the effective date of the permit
discharge from outfall(s) serial number 001. Such discharges s
below:
Flow
Toluene
Benzene
Methyl Tert Butyl Ether
'Lead
Discharge Limitation)
Monthly Averageily !a
rid lasting until expiration, the Permittee is authorized to
11 be limited and monitored by the Permittee as specified
Monitoring Requirements
Measuremerd Sample Saralple
Frequency L_ Location
Weekly Pump or Meter Log Effluent
22 µg/l Monthly Grab Effluent
142.8 µg/1 Monthly Grab Effluent
Monthly Grab Effluent
50 µgr1 Monthly Grab Effluent
There shall be no discharge of floating solids or visible foam in other than trace amounts.
The monitoring requirements and discharge limitations shall only apply if leaded petroleum products are the source of the
groundwater contamination.
Minimum treatment will include an oillwater separator, air stripping or diffused aeration and activated carbon adsorption,
Design and Construction of the Waste Treatment Facility will emphasize the use of plastic pipes and fittings where
practically possible.
GroundwnuC7 Rcrncdi 9'6tti;n

APPENDIX A
COFIFIESPONDENCE WITH ND

LU Li t.;/.0-it
'35E; PO2
State of North Carolina
Department of Environment, Health, and Natural Resources
Mooresville Regional Office
Jana . Bunt, r., Goyim= Jonathan D. SOW0011, Secretary
DIVISION OF ENVIRONMENTAL MANAGEMENT
February 3 1993
Mr. Wendell Boggs
Rhodes & Beal Oil Company
404 East Main Street
Lincolnton, North Carolina 28092
RE: Request for Extension
Bob's Food Mart
Groundwater Incident #6223
Catawba County, N.C.
Dear Mr. Boggs:
Your request for additional time for submitting the corrective
action plan at the above referenced site has been reviewed by the
Groundwater Section of the Mooresville Regional Office.
Based on the information you have provided with your request for
an extension, the request is hereby granted until March 12, 1993.
Failure to send the site assessment report by the extended due date
may result in a recommendation for the assessment of civil penalties
beginning from the original:due date.
Should you have further questions regarding this, matter, please
call Arlen Burney or me at [phone].
Sincerely,
Brenda J. Smith, P.G.
Regional Supervisor
cc: Incident Management Unit
Richard Kelly, Southeastern Geological Services
FAB/sc
PO a 950, 919 !iced, Mir Saw. Mczoossvilk, N 21015C950o TecrAvorie 704463-1659 • FAX [phone]W
An Eq..) opporwrary Affirrnative Acdon F-trOoycr

APPENDIX
GROUND 'i PATER!MODELING DATA AND RESULTS

CAPTURE ZONE MODELING
Bob's Food Mart, NC
A particle tracking groundwater flow model was employed to simulate groundwater flow
in the area of the site and determine the optimum recovery well array and flow rates. The
computer -generated model was constructed utilizing current static flow conditions as a
baseline from which to calculate the area of influence of the proposed recovery system.
The modeled system consists of two recovery wells operating under vacuum -enhanced
conditions.
The model used for this simulation was developed and released by the US EPA, and is
a semi -analytical groundwater particle tracking program. The model was chosen on the
basis of several criteria: first, the calculation methodology had to be proven and
accepted by regulatory agencies; second, the program had to produce accurate,
reproducible results; and third, the program had to be relatively easy to set up and run.
This EPA model has been in use for several years and has been recognized by state
regulatory agencies as well as the EPA. As a semi -analytical model the input parameters
are relatively easy to determine, and the program is computationally efficient* Studies
conducted prior to release by the EPA tested the model output against known case
studies with consistent accuracy.
The flow calculations used in the model are based on several assumptions typical of most
groundwater flow models: the aquifer is isotropic and behaves as though it were
homogeneous. The calculations are valid for horizontal flow conditions with fully
penetrating wells and equal horizontal and vertical hydraulic conductivities. Water table
geometry must be planar with a constant gradient. General site characteristics input to
the model were transmissivity, static saturated thickness, porosity, direction of
groundwater flow, and hydraulic gradient. These parameters were obtained or calculated
from data supplied by SEG.
Model input Parameters
Groundwater movement at this site appears to involve both the saprolite and underlying
fractured bedrock, Detection of soluble hydrocarbons in bedrock monitor wells indicates
the overburden and bedrock aquifers are likely to be hydraulically connected, allowing
the aquifer system to behave as one unit. To enable use of a simple analytical model,
several simplifying assumptions were made: the two units were assumed to behave as
though they are one continuous aquifer; local flow conditions in the area of the former
tank field were extended to the entire model domain; and the aquifer saturated thickness
was taken to be 40 feet, the sum of the overburden thickness (approximately 6 feet) and
the maximum depth into the bedrock at which soluble hydrocarbons were detected (30
to 35 feet). The effect of these assumptions will be considered during discussion of the
model results.
c1
*Index

Data supplied consisted of hydraulic conductivity (K) of the saprolite, saturated
thicknesses as described above (b), and porosity (n). The groundwater flow direction
and hydraulic gradient were determined from water table contour maps supplied by SEG
(the "Groundwater Nonrestrictive Flow" map dated 8/11/92). Flow conditions in the
former tank field area were represented by an hydraulic gradient of 0.05 feet/ft to the
southwest The hydraulic conductivity (K) used was an average of those supplied for
MW-1, MW-2, and MW-3, determined from slug tests as reported by SEG. The K
values calculated from these tests were 0.25 ft/day, 1.63 ft/day, and 0.13 ft/day,
respectively, and the average is 0.67 ft/day. The porosity supplied was 0.15. For the
model, aquifer transmissivity (T) was calculated from the hydraulic conductivity (K) and
saturated thickness (b) by the formula:
T = K b Driscoll, 1986
Using the saturated thickness of 40 feet and hydraulic conductivity of 0.67 ft/day, a
transmissivity of 26.8 ft2/day (200.5 gpd/ft) was obtained.
To calculate steady-state flow rates for the recovery wells, the aquifer specific capacity
(Qs) was estimated from Driscoll's (1986) equation:
T
05
1500
where Qs = Specific Capacity in gpm/ft,
T = Transmissivity in gpd/ft, and
Q = discharge in gpm.
In this case, T = 200.5 gpd/ft, so
Q= (200.5 gpd/ft) / 1500
= 0.13 gpm/ft.
Under atmospheric conditions, flow from the well (Q, in gpm) is:
Qs sobs
where Sobs = drawdown observed (or desired) in the well, in feet.
02

At this site, desired drawdown is 7 feet, so the theoretical atmospheric conditions flow
rate from each well would be:
Q = (0.13 gpm/ft) x (7 feet)
0.91 gpm per well.
Vacuum -Enhanced Conditions
To calculate the increased well yield realized through vacuum -enhancement, the
technique of Blake and Gates (1986) was used. The expected flow rate was determined
from the specific capacity calculated above, the actual drawdown to be attained in the
pumping wells, and the expected vacuum to be applied to the well. The drawdown
desired is 7 feet, and a vacuum of 20 inches of mercury will be applied to each well.
Since the sum of the actual drawdown in the well and the vacuum applied to the well is
the equivalent drawdown present in the well, 27 feet of equivalent drawdown was used
in the flow rate calculations below:
Q = Q
iv
where: 0 = flow rate in gpm,
©5 = specific capacity in gpm/ft, and
sequi,, = equivalent drawdown, in feet.
Since both wells would be operated at 7 feet of drawdown with a constant vacuum, the
flow rates will be equal. They were determined as follows;.
Q = (0.13 gpm/ft) x (27 feet)
3.5 gpm per well.
This is the theoretical maximum attainable flow rate with an sequin of 27 feet. The
simulations were run with flow rates of 3.5 gpm, 2.0 gpm, and 1,0 gpm per well.
Simulation Results
To simulate steady-state conditions, the simulation was run for 1 year. The model results
are presented as a particle -track plan of the recovery system capture zone, included as
Figure 14 (3.5 gpm from each well), Figure 15 (2,0 gpm), and Figure 16 (1.0 gpm) in the
body of this report. To illustrate the effect of the recovery system on the soluble plumes
detected at the site, the plots are overlain on the March 25, 1992, BTEX
lsoconcentration Map. On all Figures the green lines are groundwater particle pathlines,
and represent the distance and path a groundwater particle would be expected to follow
after pumping starts.
C3
lcindcx

These plots should be used with caution, however. Variations in conditions from those
represented by the simplifying assumptions described earlier will cause the actual capture
zone to be somewhat different from that depicted in these plots. Variations in the water
table surface will have the most pronounced effect, with the water table rise shown to the
southwest on the "Nonrestrictive Map" causing the capture zone to extend farther in that
direction and to narrow in the northwest -southeast direction. Capture of the center
portion of the plume should not be significantly affected. In addition, variability of the
hydraulic conductivity between the bedrock and overlying saprolite aquifers may cause
the well yield to be lower than expected. However, sediments with a lower hydraulic
conductivity will also require a lower flow rate to achieve the same amount of capture at
a well.
References:
Driscoll, F.G., G oundwater and Wells, Johnson Division, St. Paul, Minnesota, 1986.
Blake, S.B., and Gates, M.M., Vacuum Enhanced Hydrocarbon Recovery: A Case Study,
in Proceedings of Petroleum Hydrocarbons and Organic Chemicals in
Groundwater, NWWA/API, 1986.
C 4

EJECTORS
APPENDIX
SYSTEMS STRIPPEI3ATOR SPECIFICATIONS

EJECT
910 N lipnal Avenue
Addison, Illinois 6W01
(708) 54 -2214
FAX 708-`,A3-2014
1-& 3-O9L-LEAK
QUOTATION
HANDEX OF THE CAROLINAS
3600 G Woodpark Blvd.
Charlotte, NC
28206
Attn: Michael Jone
Phone: [phone]
FAX: [phone]
Quote Specifications:
REVISED QUOTE
Ref: Bob's Food
Quote # 930489-00
Date: 03/02/93
Terms: Net 30 days
Freight: prepaid and added
FOB Addison
Quotation is valid for 60 days
Stripperator Application Parameters (5 GPM Q 58 F):
CONSTITUENT INFLUENT DESIGN PROJECTED
EFFLUENT EFFLUENT
Benzene 3,000 ppb < 1 ppb « 1 ppb
Toluene 5,000 ppb < 10 ppb < 1 ppb
Ethyl Benzene 800 ppb < 1 ppb « 1 ppb
Xylenes 8,000 ppb < 10 ppb < 1 ppb
MTBE 5,000 ppb none <150 ppb
Effluent projections at 10 GPM are as follows:
B: <5 T: <5 EB:. <1 X: <5 MTBE: <500
The air requirement
We offer the following':
-400 CFM; the blower is 3.0 HP.
ESI Stripperator
Integrated coalescing oil/water separator and Cascade eir
stripping system with 3 HP blower and effluent sump.
Baffled separator with polypropylene coalescing pack has
gasketed removable lid. Air stripper has TEFC blower motor
and blower back pressure gauge. Constructed from epoxy
coated carbon steel..
THE UNIT LISTED INCLUDES THE FOLLOWING OPTIONAL EQUIPMENT:
Explosion proof blower motor (NEC Class 1, Div. 2, Group D).
Explosion proof motor starter (mounted and prewired).
3/4 HP XP transfer pump with level controls.
includes sump high -high switch.
igh/Low blower pressure switch (includes 25' of cord).

TO si h S IN :,
910 Naon Avenue
Addison, tUu cis 60101
(108) 5,nrn1:
FAX - 413
Iart u e '
Yours truly,
EJECTORTM $ 23C.
WilliamRecker
V ce President
MANDEX OF -`%' 3 :CAROL H.s
Quote # 910489-00
Page
is ' p11 expenses

" .
EJECTOR e';11thoiStNC
'
910 National Avenue
Addison, Illinois 60101
[phone]
FAX [phone]
1-803-01L-LEAK
ESI STRIPPERATOR
0-10 gpm coalescing oillwarer separator with 6 tube air stripper and .mcgral effluent ,sump, inclkided are
3 hp blower and back pressure guage.
STRIPPERATOR • , _ . • • • • _ • . • — _ . • — . • . • • — . — — „ S 8,575.00
3 hp TEFC blower standard
Aut STRIPPER
OlLivATER SEPARATOR
OILivATER
TtirLuENT
SEPARATOR CLEAN
OJT DRAIN
SEPARATOR
OUT DRAIN
%/ATER EFFLANT (GR.AvIT y
TRANSFER PUMP
ITEM
Blower motor starter
TEFC 3/4 hp transfer pump with level controls
coNrpot,
PANEL
.0
HATCH
%/ATER Ern...UO.0
(TRAhrSCER
ADD TO NET TOTAL
5 6,00 00
Explosion -proof blower motor
Explosion -proof blower motor starter
5 1.450,00
4 hp e.xplosion-proof transfer pump with controls
h
High effluent switch
500 00
5 1,400,00
S 2.850,00
395•00
Dimensions: 89- L x 50- W x 59" 1-1
Inlet: 2 1/2" NPIT
Outlet: 3" NPTF
Product Effluent 1 if2". NPTF
Drains: 1 112" NPTF
5 195 00

6' (CONTROL PANEL MOUIITfr�i,
AIR STRIPPER BAFFLES PLATE SUPPORTS
AIR STRIPPER TUBES
TOP ,V1
SuMP INFLUENT
STRIPPER INFLUENT
B9.D' LONG
24_©'
OIL ,CATER SEPARAT
O L/ ATER
I N F L uE N T .--f
SEPARATOR CLEAN
OUT DRAIN -
SEPARATOR CLEAN
OUT DRAIN
vATER EFFLuENT (GRAvITY DRAIN)
SUMP -'
TRANSFER PUMP
FRONT
1NSPECTIN
MATCH
ATER EFFLUENT
(TRANSFER PuHIP)'
T 4;SP SYSTFu5, INC, 1i
In S191.1.P(RA1O9

EJECTOR SYSTEMS, INC.
910 Na!ronal AN-enue
Addison, $111ncAs 60101
[phone]
FAX 7 08-543— 2Us 4
4100— OIL -/ EA K
SPECIFICATIONS FOR THE io GPM ESI STRIPPERATOR
2-18-93
The following specifications outline standard and optional equipment for the 10
gpm ES 1 Stripperator. These specifications may be altered by ESI without prior
notice
A. General
The Stripperator is a single piece of process equipment which integrates
oil/water separation and air stripping. The dimensions of the unit are
92" long X 50" wide X 65" high. Raw water will enter the unit through a
21/2* npt coupling. Separated product will exit the unit through a
11/2' npt coupling (product storage tank by others) and treated water
will exit the unit through a 3' npt coupling. No process piping between
the oil/water separator and air stripper will be required. Off gas will
exit the unit through a 6" pipe section. The outside of the Stripperator
shall be constructed of 11 gauge epoxy coated carbon steel. The Stripperator
lid is secured with latches (no bolts) and constructed of 18 gauge epoxy coated
carbon steel. The weight of the lid is 56 pounds. The unit shall include an effluent
sump. The unit includes (3) 11/2- npt drain ports, 2 for the separator and 1 for
the air stripper. The Stripperator shall be constructed to allow for pick up with
a fork lift.
Oil/water separator
The separator portion of the stripperator shall be capable of 0-10 gpm
flow rates. Separation is accomplished through the use of baffles and a clog
resistant coalescing pack. The coalescing pack will be easily removed for
cleaning. The separator shall be capable of removing 60 micron droplets at 40°F.
The separator working volume is 95 gallons. The product effluent weir is
adjustable; product will flow to an external product tank supplied by others. The
spacing on the coalescing pack is 11/2" to minimize the chance of clogging and
allow for easy cleaning. The pack angle shall be at a 60° angle to the
bottom. Flow from the separator to the air stripper will be by gravity.
No elevating of the separator is required to feed the air stripper. External piping
between the separator and the air stripper will not be allowed.

'EMIE+ TO
YSTEMS, INC.
910 Nal;onar Avenue
Addison. Illinois 6010;
[phone]
FAX [phone]
1-6[l4•OIL-LEAK
C. Air stripper
The air stripper portion of the Stripperator is similar to the Cascade
low profile air stripper as manufactured by Ejector Systems, Inc. The air
stripper is designed to handle flows up to 10 gpm. This system incorporates
bubbler aeration with a horizontal tray configuration to create the required mass
transfer. The unit employs 6 aeration tubes and 5 baffles, The aeration tubes
will be constructed of 0.035 inch thick nylon. The tubes will incorporate two rows
of 5/16" diameter holes. The large diameter holes and flexible tube material will
result in a minimum of fouling and cleaning effort. The blower shall be 3 hp TEFC
(standard) radial -blade pressure type. Standard blower electrical input is 230 volt,
single phase. Blower inlet shall be 6 inch, output shall be 400-600 cfm @ 16" w.c..
The blower shall be dynamically balanced with inlet damper and screen. Blower
shall be rated for AMCA type B spark resistance. Blower and fan blade shall be
constructed of cast aluminum. Removal of the Stripperator lid provides complete
access for cleaning the air stripper. The air stripper includes a blower back
pressure gauge. Fittings will not be allowed on the lid.
Ef1"fuent sump
The treated water frorn the air stripper will flow into an effluent sump.
The volume of the effluent sump is 60 gallons.. The standard unit will
employ gravity flow of the treated water to the final discharge point.
The sump has an inspection hatch, The sump has a floor hatch to accommodate
a vertical transfer pump.
2.

uu5u.u.5,55t
EjEGTOR SYSTEMS.NG
910 National Avenue
Addisorx,Nuats 60101
(708) 543-.2214
FAX 708,543-2014
1-80(X0IL-LEAK
E. Optlofts
1. Air stripper/blower
a. high/low pressure switch
b. Class Division II explosiort proof
c. 3-phase power
d, motor starter with disconnect
2. Effluent sump
a. 3/4 hp vertical effluent transfer pump with controls
Note: Effluent connection from the transfer pump shall be 1 ½ npt
TEFC
ii. explosion -proof
b. high -high level switch
3.