WS-4653_15063_CA_NTCP_20150828

NEW TECHNOLOGY CLEANUP PLAN
WILLIAMS GROCERY No. 15063
2425 US HIGHWAY 21
HAMPTONVILLE, YADKIN COUNTY, 27020
S&ME PROJECT # 4305-14-239
AUGUST 28, 2015
Prepared for:
North Carolina Department of Environment and Natural Resources
Division of Waste Management
Underground Storage Tank Section
1637 Mail Service Center
Raleigh, North Carolina 27699
Attention: Herb Berger
Prepared by:
S&ME, Inc.
44 Buck Shoals Road, Suite C-3
Arden, North Carolina 28704
__________________________________________________
David R. Loftis, P.E.Thomas Raymond, P.E.
Project Manager/Project Engineer Senior Engineer
S&ME is licensed to practice geology/engineering in North Carolina. Geology License Certification #C-
145 and Engineering License Certification #F-0176.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY .........................................................................................1
FEDERAL/STATE LEAD REPORT INFORMATION..........................................3
SCOPE OF SERVICES...............................................................................................4
3.1 Contract Information.......................................................................................... 4
3.2 Approved Scope of Services.............................................................................. 4
SITE HISTORY...........................................................................................................5
NEW TECHNOLOGY CLEANUP PLAN................................................................7
5.1 Extent of the Contaminant Plume...................................................................... 7
5.2 Recommended Technology for Groundwater Remediation .............................. 7
5.2.1 Air Sparge Well Network........................................................................ 8
5.2.2 Air Sparge Equipment............................................................................ 9
5.2.3 Compressed Air Lines ............................................................................ 9
5.2.4 Operational Schedule........................................................................... 10
5.2.5 Implementation Schedule and Cost...................................................... 10
5.2.6 Additional Considerations.................................................................... 10
CONCLUSIONS AND RECOMMENDATIONS...................................................12
TABLES
Table 1 Water Supply Well Information
Table 2 Monitor Well Construction and Groundwater Level Data
Table 3 Monitor Well Sampling Results
Table 4 Summary of Water Supply Well Analytical Results
Table 5 Implementation Schedule
Table 6 Estimated Implementation and Operational Costs
FIGURES
Figure 1 Site Location Map
Figure 2 Site Map
Figure 3 Water Supply Well Location Map
Figure 4 Benzene Concentration Contour Map (Feb. 25, 2014)
Figure 5 Projected Air Sparge Well Radius of Influence Relative to the Benzene
Plume
Figure 6 Projected Air Sparge Well Radius of Influence Relative to the Ethylene
Dibromide Plume
Figure 7 Projected Air Sparge Well Radius of Influence Relative to the 1,2-
Dichloroethane Plume
Figure 8 Projected Air Sparge Well Radius of Influence Relative to the MTBE
Plume
Figure 9 Remediation System Layout
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APPENDICES
Appendix I Limited Historical Data
Appendix II MicroBlower™Information
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EXECUTIVE SUMMARY
A release of petroleum constituents from a former convenience store has caused
significant impacts to the shallow groundwater on the subject site and likely off-site
properties to the east-northeast. Significant dissolved petroleum concentrations in
exceedance of the Gross Contamination Levels (GCLs) exist in three (3) monitoring
wells (MW-1, MW-3, and RW-1) located along the highway fronting the property. The
site is considered to be High Risk, as the surrounding properties utilize water supply
wells as their sole source of water.
Corrective actions regarding the presence of free product in the groundwater include
approximately 18 Aggressive Fluid/Vapor Extraction (AFVR) events from June 1997
until November 1998, and approximately six Mobile Multi-Phase Extraction (MMPE)
events performed from July 2001 until November 2003. These remedial efforts may have
resulted in the removal of free product at the site; however, little to no reduction has
occurred in the dissolved phase portion of the plume. As of February 2014, no free
product has been detected in the site’s monitoring wells.
S&ME proposes a goal to NCDENR of cost-effectively reducing the constituent
concentrations in monitor wells MW-1, MW-3, and RW-1 to concentrations below the
applicable GCLs. S&ME considers the GCL contaminant zone to be a significant source
of petroleum hydrocarbons for the migrating plume. The presence of the GCL
contaminant zone will further the likelihood that the contaminant plume will migrate off-
site and cause groundwater impacts to surrounding properties and possibly active water
supply wells.
S&ME proposes to reach this goal by the use of a temporary air sparing system that
would inject compressed air into the unconfined aquifer via three (3) proposed air sparge
wells. S&ME estimates that this goal can be accomplished with continuous operation of
the air sparging system over a period of 1 to 1.5 years.
S&ME estimates an implementation schedule of 18 weeks beginning with the preparation
of the bid specification documents and ending with the system startup. S&ME
recommends that the air sparging equipment be fabricated in an enclosed trailer so the
equipment can be relocated to other sites (directed by NCDENR) in which air sparging
could be used.
S&ME evaluated the costs associated with the implementation and operation of the
equipment under two conditions – NCDENR purchases the equipment or NCDENR
leases the equipment. If the air sparging equipment is purchased by NCDENR, S&ME
estimates an implementation cost of $48,000 to $53,000 and monthly operational costs
for the first year of approximately $17,200 annually or $1,433 monthly [total Year 1
estimated cost $65,200 to $70,200]. If NCDENR elects to lease the equipment, the
implementation cost would be reduced to approximately $28,000; however, the
operational costs (including the equipment lease costs) would be approximately $35,000
to $39,000 annually or $2,900 to $3,250 monthly [total Year 1 estimated cost $63,000 to
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$67,000]. Note: compare the proposed air sparging remediation costs to less effective
MMPE efforts at a cost of approximately $8,000 to $10,000 per MMPE event.
Due to the proximity of a residential structure to the proposed air sparging zone, the
potential exists for vapor intrusion conditions to be created in association with the
structure. S&ME proposed two options to reduce this potential – option 1: installation of
at least two (2) soil vapor extraction wells or option 2: changing the operational
characteristics, i.e., lower flowrates, of the air sparge well located near the residential
structure. The second option would also be coupled with periodic monitoring of vapors
within the residential structure by S&ME to assist in the evaluation of the future
operational characteristics of the nearby air sparge well.
Moving forward, S&ME recommends the following immediate action items:
•NCDENR and S&ME discussions regarding the vapor intrusion potential;
•Development of bid specification documents for the equipment fabrication and
piping installation;
•Provide the bid specification documents to vendors and receive costs for the
equipment fabrication (purchase and lease) and piping installation; and
•Install all components and startup the proposed remediation system.
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SCOPE OF SERVICES
3.1 Contract Information
The scope of services for this report was performed in general accordance with S&ME’s
proposal number 43-1400220 dated October 13, 2014. The scope of services was
authorized by Mr. Herb Berger with the North Carolina Department of Environment and
Natural Resources (NCDENR’s) Task Authorization 15063-01, dated October 14, 2014,
and within contract number N14005i.
3.2 Approved Scope of Services
S&ME’s approved Scope of Services for this Task Authorization included the following:
•Preparation of a New Technology Cleanup Plan with the use of a temporary air
sparing system in order to reduce the size and concentrations of the benzene and
ethylene dibromide plumes at the site.
This service was completed.
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SITE HISTORY
The subject site is located at the southwest quadrant at the intersection of US Highway 21
and Hamptonville Road in Hamptonville, Yadkin County, North Carolina (see Figure 1).
The subject site is 3.7 acres in size and is owned by Ashley Enterprises. The subject site
was formerly operated as Williams Grocery, a convenience store with retails fuel sales.
The convenience store is no longer present on the property and the property currently
contains three (3) residential structures. The subject site is predominantly surrounded by
residential properties that receive drinking water from water supply wells.
Petroleum impacts were confirmed during the removal of one 2,000-gallon gasoline and
one 550-gallon kerosene underground storage tanks (USTs) during February 1994, based
on the analytical results of soil samples collected during UST closure activities. Each
sample collected during closure activities were reported to contain total petroleum
hydrocarbons (TPH) with concentrations ranging from 42 parts per million (ppm) as
gasoline range organics to 25,000 ppm as gasoline and diesel range organics. Three
additional 550-gallon gasoline USTs were reportedly filled with concrete.The
approximate locations of the former USTs are depicted on Figure 2.
The closed in-place USTs were removed during February 1997 along with 144 tons of
petroleum-impacted soil. Four of the six confirmation soil samples collected at the
horizontal or vertical extent of the soil excavation, representing two of the former UST
locations, ranged from 2,500 ppm to 13,000 ppm TPH as gasoline range organics.
During March and April 1997, ten soil samples were collected from 12 soil borings
performed to a depth of 24 feet below ground to assess the horizontal extent of impacts
from the release. TPH was not detected in the soil samples.
Groundwater monitor wells MW-1 through MW-3 (see Figure 2) were installed on-site
and were first sampled during November 1996.
•Multiple volatile organic compounds (VOCs) were detected at concentrations
greater than the corresponding 2L Groundwater Quality Standards (2L Standards)
in groundwater samples collected in monitor well MW-2 during eight sampling
events performed from 1996 until 2012.
•Benzene, ethylene dibromide (EDB), 1,2-dichloroethane and methyl tert-butyl
ether (MTBE) were detected in groundwater samples collected from monitor well
MW-1 and MW-3 at concentrations greater than the corresponding Gross
Contaminant Levels (GCL) during sampling events performed in 2005, 2009,
2010 and 2011.
•Free product was detected in monitor wells MW-1 and MW-3 during sampling
events performed in 1996, 1998, 2003, 2004, 2008, and during June 2012.
On-site monitor well MW-4 and off-site monitor wells MW-5 through MW-11 were
installed and were first sampled during April 1998. The approximate locations of these
wells are shown on Figure 2.
•Multiple VOCs have were detected at concentrations greater than the
corresponding 2L Standards in groundwater samples collected from monitor well
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MW-5 during 10 sampling events performed from 1998 until 2012, and in
samples collected from monitor well MW-8 during eight events from 1998 until
2010. Monitor well MW-8 could not be located during the June 2012 sampling
event.
•With few exceptions, VOCs were not detected in monitor wells MW-4 and MW-6
during the same monitoring events.
•VOCs were not detected in monitor well MW-7 during 1998 and 2003; however,
benzene was reported at a concentration of 140 microgram per liter (ug/L) in
2004. Monitor well MW-7 could not be located during the 2005, 2008 or 2009
sampling events.
•Benzene was detected in monitor well MW-9 during 1998 and in monitor well
MW-10 during 2003, and 1,2-dichloroethane was detected in monitor well MW-
11 in 1998, each at concentrations greater than their 2L levels. Monitor wells
MW-9 and MW-11 could not be located during monitoring events performed
since 2003. Monitor well MW-10 has not been located since 2005.
Well RW-1 was installed in the source area and was first sampled in June 2010.
Benzene, EDB, 1,2-dichloroethane and MTBE was detected in groundwater samples
collected from well RW-1 at concentrations greater than the corresponding GCLs during
June 2010, and free product was reported in well RW-1 during June 2012.
The Groundwater Monitoring Report provided by TerraQuest (June 28, 2012)
documented the presence of 12 sole source water supply wells located within 1,000 feet
of the source area, including on-site water supply well WSW-1, and off-site water supply
wells WSW-2 through WSW-11 and WSW-18. S&ME noted references to the prior
installation of a Point-of-Entry (POE) filtration system on water supply well WSW-1 (on
the site), including analytical results for WSW1-PRE POE and WSW1-POST POE from
September 15, 2011 until June 2012. The approximate location of the water supply wells
are depicted on Figure 3 and the water supply well information is summarized in Table
1.
Additional corrective actions performed in response to the release include approximately
18 AFVR events from June 1997 until November 1998, and approximately six MMPE
events performed from July 2001 until November 2003.
S&ME performed groundwater assessment services at the site during the February 2014.
The results of these services were provided in S&ME’s Groundwater Monitoring Report
dated March 13, 2014. Below is a summary of the report:
•Free product was not detected in monitor wells MW-1, MW-2, and RW-1.
•Benzene, EDB, and 1,2-dichloroethane were detected in groundwater samples
collected from monitor wells MW-1, MW-3, and RW-1 at concentrations greater
than GCLs.
•MTBE was detected in the sample collected from monitor well MW-1 at a
concentration greater than GCL.
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•The groundwater analytical results from the monitoring wells indicated
concentrations of ten additional target petroleum constituents greater than the
corresponding 2L Standards, but less than the GCLs, in the samples collected
from monitor wells MW-1, MW-3 and RW-1, including DIPE, ethylbenzene,
isopropylbenzene, naphthalene, n-propylbenzene, styrene, toluene, 1,2,4-
Trimethylbenzene, 1,3,5-Trimethlybenzene and Total Xylenes.
•No target VOCs were detected in the samples collected from monitor wells MW-
2, MW-4, MW-5, and MW-6.
•No target VOCs were detected in groundwater samples collected from water
supply wells WSW-1, WSW-2, WSW-3, WSW-4, WSW-5, WSW-6, and WSW-
7; all active wells located within 1,000 feet of the source area.
Table 2 contains a summary of the well construction and depth to groundwater data
collected during the February 2014 assessment activities. The most recent groundwater
sampling results for the monitor and water supply wells are summarized in Tables 3 and
4, respectfully. A summary of the historical groundwater data is provided in Appendix I.
NEW TECHNOLOGY CLEANUP PLAN
5.1 Extent of the Contaminant Plume
The current extent of the contaminant plume as represented by the concentration of
benzene in the shallow groundwater from the February 2014 sampling event is shown on
Figure 4. As shown, the core of the plume in exceedance of GCLs is centered among
monitor wells MW-1, MW-3, and RW-1 and is hereby referred to as the GCL
contaminant zone. A review of the historical data in Appendix I suggests that wells MW-
1, MW-3, and RW-1 have consistently yielded contaminant concentrations in exceedance
of the GCLs and/or contained free product since the wells were installed; 1996 for MW-1
and MW-3 and 2010 for RW-1.
While recent groundwater samples from off-site monitoring wells have not detected
target petroleum constituents, historical data suggests that petroleum contaminants have
been detected on the northeastern adjoining property; namely in monitor wells MW-5,
MW-6, and MW-8. The lack of petroleum detections in recent samples collected from
monitor wells MW-5 and MW-6 suggest that multiple release events may have taken
place in association with the former UST system or possibly from a previous
generation(s) UST system. Consequently, one has to assume that the current contaminant
plume will continue to migrate with the shallow groundwater to the east-northeast, across
US Highway 21 towards the northeastern adjoining property.
5.2 Recommended Technology for Groundwater Remediation
As noted in Section 4, 18 AFVR events and approximately six MMPE events were
previously performed. These remedial efforts may have resulted in the removal of free
product at the site; however, little to no reduction has occurred in the dissolved phase
portion of the plume. As indicated in the current data, significant dissolved
concentrations of benzene, EDB, 1,2-dichloroethane exist in monitor wells MW-1, MW-
3, and RW-1 and MTBE in MW-1.
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S&ME does not recommend the continued use of AFVR and MMPE techniques to
further remediate the site groundwater. AFVR and MMPE techniques are essentially a
short term exercise in pump and treat and are typically not effective in the removal of
dissolved petroleum constituents from the groundwater. Pump and treat techniques,
when used for the removal of dissolved constituents form the groundwater, tend to be
expensive and inefficient.
Instead, S&ME recommends that a network of air sparging wells be installed and
operated within the GCL contaminant zone as a means to reduce the dissolved
concentrations of these contaminants. S&ME considers the GCL contaminant zone to be
a significant source of petroleum hydrocarbon for the migrating plume. The presence of
the GCL contaminant zone will further the likelihood that the contaminant plume will
migrate off-site and cause groundwater impacts to surrounding properties and possibly
active water supply wells.
Air sparging is a proven groundwater remediation technology that involves the injection
of compressed air into the unconfined groundwater aquifer. The injection of this
compressed air strips the volatile contaminants from the groundwater and stimulates the
aerobic biodegradation of hydrocarbons via the addition of dissolved oxygen to the
groundwater.
S&ME recommends that the short term goal for groundwater remediation at the subject
site be to reduce the constituent concentrations in wells MW-1, MW-3, and RW-1 to
concentrations below GCLs. Based on our experience with similar sites, S&ME
recommends a time frame of one year to 18 months to reach this goal.
5.2.1 Air Sparge Well Network
In selecting the number and location of air sparge wells, S&ME assumed a radius of
groundwater influence of 25 feet for each air sparge well. Based on S&ME’s experience,
the assumed radius of influence is a conservative estimate for sites in the Piedmont
physiographic province.
S&ME also considered location of the North Carolina Department of Transportation
(NCDOT) Right-of-Way (ROW) in association with US Highway 21 and Hamptonville
Road. On October 27, 2014, Mr. Bradley Keyse with S&ME spoke with Mr. Jacob
Bryant, ROW Agent with the NCDOT Division 11. According to Mr. Bryant, the
NCDOT did not have documentation for the ROW and to use the “maintained limits”
defined by Mr. Bryant as ditch-line to ditch-line as the presumed NCDOT ROW.
S&ME recommends that three (3) air sparge wells be installed in the GCL contaminant
zone.Figures 5,6,7, and 8 depict the recommended air sparge well locations with the
radius of influence relative to the presumed NCDOT ROW and the benzene, EDB, 1,2-
dichlorothane, and MTBE groundwater plumes, respectfully. As can been seen from the
figures, the recommended air sparge layout should effectively influence the GCL
contaminant zone.
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S&ME recommends that the air sparge wells be constructed of 2-inch well casing
inserted into an approximate 8-inch diameter borehole to a depth of approximately 40
feet below grade (BG) or 18 feet below the apparent depth to groundwater. The well
screen should be constructed of 0.010-inch slotted screen and no more than 5 feet in
length.
5.2.2 Air Sparge Equipment
An air compressor, filtration system, and distribution manifold is necessary to make
compressed air and distribute the compressed air to the air sparge well network. S&ME
recommends the following pertinent equipment:
•Minimum 10 horsepower rotary screw compressor with accompanied pressure
tank;
•Filtration system that includes two (2) coalescing filters to remove oil from the air
stream and one (1) particulate filter to remove particulates from the air stream;
•A distribution manifold that includes three (3) legs, one for each air sparge well.
Each leg should include an electric solenoid, flow controller, pressure regulator
with liquid-filled pressure gauge, and flowmeter; and
•Programmable logic controller (PLC) to (1) control the operation/cycling of each
air sparge well, (2) log the run time for the air compressor and each air sparge
well, and (3) provide auto-restart capability or the ability to restart the equipment
should a power interruption occur.
Typically, the air sparge equipment is mounted to a skid and placed on a concrete slab
with security fence or installed inside a pre-fabricated metal building that rests on a slab.
S&ME recommends that NCDENR consider having the air sparge system fabricated
within an enclosed trailer so the equipment can be relocated to other sites in which air
sparging could be used. The proposed location of the air sparge equipment is illustrated
on Figure 9.
Based on the power line configuration observed at the site, 3-phase electricity appears to
be available to the subject site. Therefore, the equipment can be fabricated to utilize 3-
phase electric power, which tends to more efficient, i.e., uses less energy, compared to
single-phase power. However, 3-phase power is not available to all sites and in many
rural location only single-phase power is available. If NCDENR would like the
flexibility of using this equipment in other locations, S&ME recommends that NCDENR
consider fabricating the equipment to use single-phase power.
5.2.3 Compressed Air Lines
The compressed air leaving the distribution manifold should be routed to each of the air
sparge wells using individual reinforced rubber hose that is a minimum ¾-inch in
diameter. Each hose should be encased in individual 2-inch diameter poly vinyl chloride
(PVC) Schedule 40 pipe and be installed in trenches approximately 18-inches wide and
18-inches deep. The chase pipe will offer protection to the hose and a means to install
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new hose should the originally-installed hose fail. The proposed trench lines are depicted
on Figure 9.
5.2.4 Operational Schedule
S&ME recommends that the air sparge equipment be operated continuously, 7 days a
week, 24 hours a day. Operations and maintenance visits should be made weekly during
the first month of operation and every 2 to 4 weeks thereafter. During each visit, routine
maintenance should be performed on the compressor, including lubricant
check/adding/change, check/change the compressor intake filter, and check/tighten the
belt(s). During each visit, the run time for the system and each individual air sparge
should be logged in order to evaluate the percentage runtime of the system and air sparge
wells.
At least once a month, the depth of water, dissolved oxygen, and volatile organic
concentrations should be measured from each monitoring well located within the air
sparging treatment zone. The data collected from the monitoring wells will be used
gauge the effectiveness of the air sparge well network in stripping volatiles from the
groundwater and adding dissolved oxygen to the shallow aquifer.
5.2.5 Implementation Schedule and Cost
S&ME estimates an implementation schedule of 18 weeks beginning with the preparation
of the bid specification documents and ending with the system startup.Table 5 provides
detail regarding the estimate completion time for the major tasks involved in the system
implementation.
S&ME also prepared an estimated cost to implement the system and annual costs for
operating the equipment. Assuming that NCDENR would purchase the equipment (not
lease), the estimated cost to implement the system, which includes the air sparge well
installation, equipment purchase and installation, trenching and piping, and system
inspections and startup ,would be approximately $48,000 to $53,000. The operational
costs associated with the equipment for the first year would be approximately $17,200.
The detail associated with the provided cost estimates is provided in Table 6.
If NCDENR elected to lease the equipment, the implementation costs would be reduced
to $28,000; however, the annual operational costs (including the equipment lease costs)
would be approximately $35,000 to $39,000. Additional detail is provided in Table 6.
5.2.6 Groundwater Monitoring
S&ME recommends that quarterly groundwater samples be collected from the site’s
monitoring wells to document the effectiveness of the remedial system. The samples
should be analyzed for VOCs by Standard Method (SM) 6200B.
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5.2.7 Additional Considerations
5.2.7.1 Vapors
As previously noted, air sparging activities produce vapors as a result of the
hydrocarbons being stripped from the groundwater. For this reason, air sparge systems
are typically coupled with a soil vapor extraction system to scavenge these vapors and
exhaust them into the atmosphere. Soil vapor extraction systems are typically comprised
of an electric blower connected to several soil vapor extraction wells that are installed
and screened within the vadose zone.
In the case of the Williams Grocery site, the site cover is grass and gravel; therefore,
vapors that are produced by the air sparging activities can migrate vertically, exit the
subsurface, and enter the atmosphere. A review of the Well Construction Records
provided in Engineering Consulting Services’s (ECS)Report of Well Installation and
Groundwater Sampling report dated June 10, 1997 indicate no significant confining
layers are present within the subsurface that would prevent the vertical migration of
vapors to the atmosphere. However, it should be noted that several residential structures
are located on the property.
Two apartment structures are located approximately 110 feet from the proposed air
sparge wells. Vapors generated by the air sparging activities should have a low potential
to create a vapor intrusion issue in association with the apartment structures. However,
the residential structure south of monitor well MW-1 is approximately 35 feet from the
nearest air sparge well and could be impacted by a vapor intrusion condition. Based on
an exterior view, the residential structure appears to be comprised of both slab-on-grade
and crawlspace foundation systems.
One option to remedy this issue is to install one or more soil vapor extraction wells
between the southernmost proposed air sparge well and the residential structure. The soil
vapor extraction wells would act as a venting system to allow vapors to exit the
subsurface before encountering the footprint of the residential structure. S&ME
recommends at least two soil vapor extraction wells for this option. The vapor extraction
points can be operated passively, i.e., open to the atmosphere, or with a small blower at
each extraction well.
Tersus Environmental markets the MicroBlower™that can be installed at each soil vapor
extraction point to actively pull vapors from the subsurface. The MicroBlower™can
produce air flows greater than 1 standard cubic feet per minute and can be powered via
wind or solar energy. Additional information for the MicroBlower™is included in
Appendix II. S&ME would like to evaluate the estimated costs for the soil vapor
extraction wells and associated equipment such as the MicroBlower™following
discussions of the vapor intrusion potential with NCDENR.
Another option to reduce the potential for vapors to impact the nearby residential
structure would be to operate the southernmost proposed air sparge well at a very low
flowrate (< 1 actual cubic foot per minute). Operating this air sparge well at a low
flowrate would lessen the volume of vapors created in the subsurface in the vicinity of
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the nearby house. S&ME can monitor the interior of the residential structure during each
site visit for the presence of vapors using an Organic Vapor Analyzer (OVA) meter or by
the installation of a VOC monitor and alarm. Following the collection of OVA data,
S&ME can evaluate the current vapor conditions to determine future operational
characteristics of the nearby air sparge well.
5.2.7.2 Overhead Obstructions
It should be noted that overhead power lines exist on the east side of US Highway 21 and
would be in or near the work area during air sparge well installation activities. Thus,
mast-down drilling techniques and/or line shielding may have to be implemented to
install the air sparge wells. This techniques and/or procedures may increase the costs
associated with the well installations.
CONCLUSIONS AND RECOMMENDATIONS
Following a review of the current contaminant plume conditions, S&ME recommends
that an air sparging system comprised of three (3) air sparge wells, an air compressor, and
distribution manifold be operated at the site. S&ME recommends operation of the air
sparge system as a means to reduce the concentrations of petroleum constituents in the
groundwater in the vicinity of wells MW-1, MW-3, and RW-1 with an ultimate goal of
reducing the contaminant concentration below the applicable GCLs. S&ME estimates
that this goal can be accomplished with continuous operation of the air sparging system
over a period of 1 to 1.5 years. If the GCL contaminant zone is left unchecked, the
contaminant plume will continue to migrate off-site and cause groundwater impacts to
surrounding properties and possibly active water supply wells.
S&ME estimates an implementation schedule of 18 weeks beginning with the preparation
of the bid specification documents and ending with the system startup. S&ME
recommends that the air sparging equipment be fabricated in an enclosed trailer so the
equipment can be relocated to other sites (directed by NCDENR) in which air sparging
could be used.
The capital and O&M costs associated with the system as evaluated for the purchase and
lease options are presented below:
Options Estimated Capital Costs Estimate O&M Costs
(per year)
Purchase $48,000 - $53,000 $17,200
Lease $28,000 $35,000 - $39,000
Based on a review of the estimated cost data, S&ME recommends that the system be
purchased by NCDENR as the breakeven point is just over one year. The breakeven
point is defined at the point in time at which the cost of the purchasing the equipment is
less than the cumulative cost of leasing the equipment.
The potential exists for vapor intrusion conditions to be created in association with a
residential structure located in the vicinity of the proposed air sparging zone. S&ME
New Technology Cleanup Plan, TF-15063 S&ME Project No. 4305-14-239
Williams Grocery, 2425 US Highway 21, Hamptonville, Yadkin County, NC August 28, 2015
13
proposed two options to reduce this potential – option 1: installation of at least two (2)
soil vapor extraction wells or option 2: changing the operational characteristics, i.e.,
lower flowrates, of the air sparge well located near the residential structure. The second
option would also be coupled with periodic monitoring of vapors within the residential
structure by S&ME to assist in the evaluation of the future operational characteristics of
the nearby air sparge well.
FIGURES
0GRAPHIC SCALE1,0005001,000SCALE: 1" = 1,000'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgSITE LOCATION MAPWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2391DEC. 2014AS SHOWNRDMALBHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 150631,500 'SITE/2&$7,21ƒ
1ƒ
:(Google Earth)SOURCE: BROOKS CROSSROADS, NC USGS TOPOGRAPHIC MAP, 7.5-MINUTE SERIES, DATED 2013 (www.usgs.gov)SCALE: 1" = 1,000'
MW2MW1MW4MW3MW50GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgSITE PLANWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2392DEC. 2014AS SHOWNRDMALBHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063Reference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERWILLIAMSGROCERYLEGEND- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- FORMER UST LOCATIONNOTE: LOCATIONS SHOWN ARE APPROXIMATEHOUSEMW6WSW1WSW5(WALL)WSW3(CHURCH)RW1HOUSEHOUSEAPTFORMERSHELLSTATION &MOBILE HOMEAPTPROPERTY

BOUNDAR
Y
0GRAPHIC SCALE500250500SCALE: 1" = 500'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgWATER SUPPLY WELLLOCATION MAPWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2393DEC. 2014AS SHOWNRDMALBHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 150631,
0
0
0

'
50
0

'US Hwy 21Hamptonville RdLEGEND- WATER SUPPLY WELL1,500 'Pet
ty
RdWSW1WSW3(Church)WSW5(Wall)WSW6(Gardner)WSW8WSW17WSW18WSW2(Gail)WSW4(Shore)WSW7(Windsor)WSW9WSW10WSW11WSW16WSW15WSW12WSW14WSW13Reference: "SITE VICINITY MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 2, dated 1/20/10 and 2010 aerial photograph obtained from www.nconemap.com. Parcel data obtained from Yadkin County GIS website
0GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgBENZENE CONCENTRATION CONTOUR MAP (FEB. 25, 2014)WILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2394DEC. 2014AS SHOWNRDMALBHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063LEGEND- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- BENZENE CONCENTRATION IN ug/L- BENZENE ISOCONCENTRATION CONTOUR- 2L STANDARD- GROSS CONTAMINANT LEVEL- MICROGRAMS PER LITERMW2MW1MW4MW3MW5FORMERWILLIAMSGROCERYHOUSEMW6WSW1WSW3(CHURCH)RW1HOUSEHOUSEAPTAPTReference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERSHELLSTATION &MOBILE HOME1 ug/L5,000 ug/Lug/LPROP
ERTY
BOUND
ARY WSW5(WALL)
0GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2395DEC. 2014AS SHOWNRDMDRLHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063LEGEND- APPROXIMATE EDGE OF MAINTAINEDPROPERTY OR ASSUMED NCDOTRIGHT-OF-WAY- PROPOSED AIR SPARGE WELL LOCATION WITHASSUMED RADIUS OF INFLUENCE OF 25 FT- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- BENZENE CONCENTRATION IN ug/L- BENZENE ISOCONCENTRATION CONTOUR- 2L STANDARD- GROSS CONTAMINANT LEVEL- MICROGRAMS PER LITERMW2MW1MW4MW3MW5FORMERWILLIAMSGROCERYHOUSEMW6WSW1WSW3(CHURCH)RW1HOUSEHOUSEAPTAPTReference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERSHELLSTATION &MOBILE HOME1 ug/L5,000 ug/Lug/LPROP
ERTY
BOUND
ARY WSW5(WALL)
PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2396DEC. 2014AS SHOWNRDMDRLHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063LEGEND- APPROXIMATE EDGE OF MAINTAINED PROPERTY ORASSUMED NCDOT RIGHT-OF-WAY- PROPOSED AIR SPARGE WELL LOCATION WITHASSUMED RADIUS OF INFLUENCE OF 25 FT- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- ETHYLENE DIBROMIDE CONCENTRATION IN ug/L- ETHYLENE DIBROMIDE ISOCONCENTRATION CONTOUR- 2L STANDARD- GROSS CONTAMINANT LEVEL- MICROGRAMS PER LITERMW2MW1MW4MW3MW5FORMERWILLIAMSGROCERYHOUSEMW6WSW1WSW3(CHURCH)RW1HOUSEHOUSEAPTAPTReference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERSHELLSTATION &MOBILE HOME0.02 ug/L50 ug/Lug/LPROP
ERTY
BOUND
ARY WSW5(WALL)0GRAPHIC SCALE10050100SCALE: 1" = 100'
LEGEND- APPROXIMATE EDGE OF MAINTAINED PROPERTY ORASSUMED NCDOT RIGHT-OF-WAY- PROPOSED AIR SPARGE WELL LOCATION WITHASSUMED RADIUS OF INFLUENCE OF 25 FT- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- 1,2-DICHLOROETHANE CONCENTRATION IN ug/L- 1,2-DICHLOROETHANE ISOCONCENTRATION CONTOUR- 2L STANDARD- GROSS CONTAMINANT LEVEL- MICROGRAMS PER LITERMW2MW1MW4MW3MW5FORMERWILLIAMSGROCERYHOUSEMW6WSW1WSW3(CHURCH)RW1HOUSEHOUSEAPTAPTReference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERSHELLSTATION &MOBILE HOME0.4 ug/L400 ug/Lug/LPROP
ERTY
BOUND
ARY WSW5(WALL)0GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2397DEC. 2014AS SHOWNRDMDRLHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063
LEGEND- APPROXIMATE EDGE OF MAINTAINED PROPERTY ORASSUMED NCDOT RIGHT-OF-WAY- PROPOSED AIR SPARGE WELL LOCATION WITHASSUMED RADIUS OF INFLUENCE OF 25 FT- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- MTBE CONCENTRATION IN ug/L- MTBE ISOCONCENTRATION CONTOUR- 2L STANDARD- GROSS CONTAMINANT LEVEL- MICROGRAMS PER LITER- METHYL TERT-BUTYL ETHERMW2MW1MW4MW3MW5FORMERWILLIAMSGROCERYHOUSEMW6WSW1WSW3(CHURCH)RW1HOUSEHOUSEAPTAPTReference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERSHELLSTATION &MOBILE HOME20 ug/L20,000 ug/Lug/LPROP
ERTY
BOUND
ARY WSW5(WALL)MTBE0GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2398DEC. 2014AS SHOWNRDMDRLHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063
MW2MW1MW4MW3MW50GRAPHIC SCALE10050100SCALE: 1" = 100'PROJECT NO.DATE:FIGURE NO.SCALE:WWW.SMEINC.COM3718 OLD BATTLEGROUND ROADGREENSBORO, NC 27410PH. 336-288-7180FAX. [phone]DRAWN BY:CHECKED BY:DRAWING PATH:Q:\4341\2014\14-239 - WILLIAMS GROCERY\Williams Grocery Site.dwgREMEDIATIONSYSTEM LAYOUTWILLIAMS GROCERY2425 U.S. HIGHWAY 214341-14-2399DEC. 2014AS SHOWNRDMDRLHAMPTONVILLE, YADKIN COUNTY, NORTH CAROLINAINCIDENT No. 15063Reference: "SITE LAYOUT MAP, FORMER WILLIAMS GROCERY", by Terraquest Environmental Consultants,Figure 3, dated 6/28/12, and 2010 aerial photograph obtained from www.nconemap.comFORMERWILLIAMSGROCERYLEGEND- APPROXIMATE EDGE OF MAINTAINED PROPERTYOR ASSUMED NCDOT RIGHT-OF-WAY- PROPOSED AIR SPARGE WELL LOCATION WITHASSUMED RADIUS OF INFLUENCE OF 25 FT- MONITORING WELL LOCATION- WATER SUPPLY WELL LOCATION- FORMER UST LOCATIONNOTE: LOCATIONS SHOWN ARE APPROXIMATEHOUSEMW6WSW1WSW5(WALL)WSW3(CHURCH)RW1HOUSEHOUSEAPTFORMERSHELLSTATION &MOBILE HOMEAPTPROPERTY

BOUNDAR
YPROPOSED LOCATION OFREMEDIATIONEQUIPMENTPROPOSED REMEDIATION SYSTEMTRENCH LINE
TABLES
Ashley Enterprises 2425 US Highway 21
2117 US HWY 21 S.Hamptonville, NC 27020
Hamptonville, NC 27020
WSW2 Sandra Gail 2032 Petty Rd.
Gail 2508 US HWY 21 Hamptonville, NC 77020
Hamptonville, NC 27020
WSW3 Delma Church (deceased)1704 Hamptonville Rd.
Church 1704 Hamptonville Rd.Hamptonville, NC 27020
Hamptonville, NC 27020
WSW4 Derek A Shore 2424 US Highway 21
Shore 2424 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
WSW5 Wesley Wall 1708, 1712 Hamptonville Rd.
Wall PO Box 206 Hamptonville, NC 27029
Sullivan Island, SC 29482
WSW6 John H. Gardner (deceased)1717 Hamptonville Rd.
Gardner 1717 Hamptonville Rd.Hamptonville, NC 27020
Hamptonville NC 27020
WSW7 Terry Windsor 2405 US Highway 21
Windsor 4139 Old US HWY 21 Hamptonville, NC 27020
Hamptonville NC 27020
Jerry Wall 1737 Hamptonville Rd.
PO Box 509 Hamptonville, NC 27020
Hamptonville, NC 27020
Willis Scowls 2401 US Highway 21
2401 US HWY 21 Hamptonville, NC 27020
Hamptonville NC 27020
Olen King 2345 US Highway 21
2345 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
Charles Moorefield 2337 US Highway 21
2337 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
Minnie Chappell 1515 Dooley Rd.
1308 Ruck Sholes Rd.Hamptonville, NC 27020
Hamptonville, NC 27020
Undo S. Wall 2352 US Highway 21
2352 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
Minnie Chappell 1515 Dooley Rd.
1308 Buck Sholes Rd.Hamptonville, NC 27020
Hamptonville, NC 27020
Ralph Talley 2328 US Highway 21
7328 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
Walter Durham 2325 US Highway 21
2329 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
Glenn Wall 1744 Hamptonville Rd.
1744 Hamptonville Rd Hamptonville NC 27020
Hamptonville, NC 27020
Bobby D. Church 2516 US Highway 21
2516 US HWY 21 Hamptonville, NC 27020
Hamptonville, NC 27020
2425 US HIGHWAY 21, HAMPTONVILLE, NC
Well AddressWell Owner/AddressWell ID No
Distance from Source
Area of Release (feet)
unknown 345
sole source unknown Drilled unknown unknown 642
sole source unknown
Well Depth
(feet BGS)Well Use
unknown 820
sole source unknown unknown unknown
sole source unknown unknown unknown
unknown 397
sole source unknown unknown unknown
unknown unknown
unknown 103
sole source unknown unknown unknown unknown 303
sole source unknown
925
655
WSW8
sole source
unknown unknown
unknown unknown unknown unknown
468 450
unknown
WSW12
sole source
WSW9
sole source unknown unknown unknown unknown
WSW13
sole source unknown unknown unknown unknown
unknown 943
WSW10
note source
unknown unknown unknown unknown 1,040
unknown unknown unknown unknown 695
WSW11
solo source unknown unknown
3. Well ID numbers are displayed on Figure 2.
unknown
1,291
692
Notes:
1,317
WSW14
sole source
unknown 1,044
WSW16
sole source unknown unknown unknown
WSW15
sole source unknown unknown unknown unknown
1. "BGS" =feet below ground surface.
2. Information obtained from Terraquest Water Supply Well Information table (June 2012), telephone and field Interviews (February 2014) and Yadkin County GIS; revised information shown in itlaics.
unknown
TABLE 1
WATER SUPPLY WELL INFORMATION
WILLIAMS GROCERY, INCIDENT # 15063
S&ME PROJECT NO. 4305-14-239
Screen Interval
(feet BGS)
Casing Depth
(feet BGS)Type of Well
WSW1
on site
WSW18
sole source unknown unknown unknown
WSW17
unknown
sole source unknown unknown unknown
1,463
unknown unknown unknown 1,117
Well ID
Top of
Casing
Elevation*
(ft.)
Depth to Water
from Top
of Casing (ft.)
February 25, 2014
Groundwater
Elevation*
(ft.)
MW-1 23 to 33 498.82 22.28 476.54
MW-2 20 to 30 499.27 22.47 476.80
MW-3 23 to 33 499.47 22.78 476.69
MW-4 24 to 34 499.45 22.77 476.68
MW-5 24 to 34 498.34 22.54 475.80
MW-6 24 to 34 495.39 19.24 476.15
RW-1 17 to 32 499.38 22.75 476.63
Top of Casing Elevations provided from previous consultant reports.
Screen
Interval
(x to y ft.
BGS)
Note: MW-7, MW-8, MW-9 and MW-10 were reported as "could not locate" in previous
monitoring reports.
TABLE 2
MONITOR WELL CONSTRUCTION AND GROUNDWATER
LEVEL DATA
WILLIAMS GROCERY, INCIDENT #15063
2425 US HIGHWAY 21, HAMPTONVILLE, NC
S&ME PROJECT NO. 4305-14-239
Method
Monitor
Well
Number
Date
Sampled Benzene1,2-Dibromo-ethane(EDB)1,2-Dichloro-ethaneDiisoporpyletherEthylbenzeneIsopropyl-benzeneMethl-tert-butyletherNaphthalenen-PropylbenzeneStyreneToluene1,2,4-Trimethyl-benzene1,3,5-Trimethyl-benzeneXylenes(total)MW-1 2/25/2014 24,800 1,440 2,860 744 2,890 144 66,200 1,090 438 103 32,900 3,880 1,110 19,280
MW-2 2/25/2014 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <2.0 <0.50 <0.50 <0.50 <0.50 <0.50 <1.0
MW-3 2/25/2014 17,500 1,030 607 149 3,570 192 598 1,340 624 176 37,500 4,980 1,400 23,020
MW-4 2/25/2014 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <2.0 <0.50 <0.50 <0.50 <0.50 <0.50 <1.0
MW-5 2/25/2014 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <2.0 <0.50 <0.50 <0.50 <0.50 <0.50 <1.0
MW-6 2/25/2014 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <2.0 <0.50 <0.50 <0.50 <0.50 <0.50 <1.0
RW-1 2/25/2014 30,200 998 1,620 590 3,350 118 7,980 1,040 343 202 47,100 2,900 653 19,160
1 0.02 0.4 70 600 70 20 6 70 70 600 400 400 500
5000 50 400 70,000 84,500 25,000 20,000 6,000 30,000 70,000 260,000 28,500 25,000 85,500
Dissolved concentrations reported in micrograms per liter (ug/L)
NCAC 2L = NCAC 2L Groundwater Quality Standards for Class GA groundwater
GCL = Gross Contaminant Level
Bold concentrations exceed the NCAC 2L groundwater standards for Class GA groundwater
Shaded concentrations exceed the GCL
Only detected analytes are shown
6200B
TABLE 3
MONITOR WELL SAMPLING RESULTS
WILLIAMS GROCERY, INCIDENT #15063
2425 US HIGHWAY 21, HAMPTONVILLE, NC
S&ME PROJECT NO. 4305-14-239
NCAC 2L (ug/L)
GCL (ug/L)
Well ID Date
BenzeneTolueneXylenes(Total)Methyltert-butyletherNaphthaleneDiisopropyletherChloromethane1,2-DichloroethaneIsopropylbenzene1,2,4-Trimethylbenzene1,3.5-TrimethylbenzeneWSW-1 6/14/2010 63 0.95 13.84J 28 2.6 0.69 0.97 1.3 <0.034 <0.038 0.80
9/13/2010 55 0.79 16 24 3.4 0.63 <0.032 1 0.67 1.2 1.1
2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-2 2/25/2014 <0.50 <0.50 <1.0 <0.5 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-3 2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-4 2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-5 2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-6 2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
WSW-7 11/30/2009 <0.040 <0.060 <0.19 <0.11 <0.23 <0.080 NA 0.63 <0.10 <0.14 <0.080
12/6/2011 <0.054 <0.057 <0.17 <0.056 <0.094 <0.042 <0.032 0.52 <0.034 <0.038 <0.038
6/13/2012 <0.054 <0.057 <0.17 <0.056 <0.094 <0.042 <0.032 0.52 <0.034 <0.038 <0.038
2/25/2014 <0.50 <0.50 <1.0 <0.50 <2.0 <0.50 <1.0 <0.50 <0.50 <0.50 <0.50
2L Standard 1 600 500 20 6 70 3 0.4 70 400 400
Notes:
Concentrations are reported in micrograms per liter (mg/L) or parts per billion (ppb)
Only contaminants detected above the method detection limits in water supply wells during previous monitoring events are shown
(Historical analytical results for the water supply wells shown and wells WSW-8 through WSW-11 and WSW-18 are included in Appendix II.)
Concentrations shown in bold exceed the corresponding North Carolina groundwater quality standard (2L Standard)
NA - not analyzed or data not available
J-Estimated concentration
S&ME PROJECT NO. 4305-14-066
TABLE 4
SUMMARY OF WATER SUPPLY WELL ANALYTICAL RESULTS
WILLIAMS GROCERY, INCIDENT #15063
2425 US HIGHWAY 21, HAMPTONVILLE, NC
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Task No. Task Description
1 Preparation of Bid Specification for Equipment
and Piping Installation
2 Vendor Bid
3 Contracts Awarded
4
Air Sparge Well Installation (Coordination and
Field Work)
5 Equipment Fabrication and Installation
6 Piping Installation
7 Temporary Electrical Service
8 System Startup
Weeks
TABLE 5
IMPLEMENTATION SCHEDULE
WILLIAMS GROCERY, INCIDENT #15063
2425 US HIGHWAY 21, HAMPTONVILLE, NC
S&ME PROJECT NO. 4305-14-066
Applicable
TaskCode TaskDescription Capital Cost Monthly Cost Annual Cost Comments
3.101 Supervision of Field Work (Type II Well)$1,200 $0 $0 3 air sparge wells @ 40 feet each
3.113 2-inch Well (air sparge wells)$5,400 $0 $0 3 air sparge wells @ 40 feet each
3.398 Drill Rig Mobilization $350 $0 $0
7.015 Design/Specify Remediation System $3,000 $0 $0
7.060 Cost for Air Sparge System1(estimated)$20,000 - $25,000 $0 $0
7.060 Cost for Air Sparge System (temporary power service; estimated)$2,000 $0 $0
7.410 Lease Remediation System (estimated)-$1,500 - $1,800 $18,000 - $21,600
7.100 Cost for Installation of Remediation System $14,000 --Estimate from SAEDACCO
7.081 Remediation System Install Inspection $1,164 --
Three visits total; one to inspect system at the vendor facility (4
hours), one to inspect piping installation (4 hours), and one for system
startup (4 hours). $97 per hour
12.010 Consultant Travel (estimated)$515 --Associated with Task 7.081. 3 visits @ 250 miles roundtrip each.
TOTAL $47,629 - $52,629 --
7.210 Cost for Remedial System Maintenance (1st month)$1,674 3 weekly visits, 6 hours each @ $93 per hour
7.210 Cost for Remedial System Maintenance (remaining months)$558 monthly visits, 6 hours each @ $93 per hour
7.250 Cost for Remdiation Supplies (estimated)$200 $2,400
7.260 Cost for Remdiation Operaton Expenses Supplies (estimated)$500 $6,000
12.010 Consultant Travel (1st month)$747 Associated with Task 7.210. 3 trips @ 120 miles roundtrip.
12.010 Consultant Travel (remaining months)$249 Associated with Task 7.210. 120 miles roundtrip.
TOTAL $17,208
NOTES:
1 Assumed to be trailer-mounted
$996
$7,812
Implementation Costs
Operational Costs
TABLE 6
ESTIMATED IMPLEMENTATION AND OPERATIONAL COSTS
WILLIAMS GROCERY, INCIDENT #15063
2425 US HIGHWAY 21, HAMPTONVILLE, NC
S&ME PROJECT NO. 4305-14-066
APPENDIX I
Limited Historical Data
APPENDIX II
MicroBlower™Information

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MicroBlower is a low-cost alternative designed to run on
renewable sources of energy such as solar and wind energy
to treat volatile organic compound (VOC) contamination in
the unsaturated zone. By using renewable sources of
energy, the blowers eliminate the need for an external
power supply and other ancillary infrastructure generally
required for conventional ASVE systems. With the solar or
wind option, a small battery bank stores power for when the
sun or wind energy is inadequate. The MicroBlower can
also run on a 24-volt DC power supply. MicroBlower’s high
quality components allow for a long operating life. The
small size and very low O&M expenses of the system make
MicroBlower useful for long-term cleanup operations,
particularly where mass transfer limits the rate of remediation.

MicroBlowers are ideal for remote locations with limited or no ancillary infrastructure. By using renewable
sources of energy, the MicroBlower eliminates the need for generators and fuel storage at remote
locations. The MicroBlower design also eliminates ancillary infrastructure that is generally required to run
conventional ASVE systems in remote areas. MicroBlowers offer the advantage of a reduced carbon
footprint and very low O&M expenses.

Ideal for Long-Term Remediation

Pumping: The pump is capable of producing flows greater than1 scfm at pressures or vacuums
typical of subsurface situations.

Power: The system requires less than 40 watts of power, easily produced by a small photovoltaic
panel, battery or wind turbine.

Size: The units are small and unobtrusive for long-term operations – 4 inches in height and 3
inches in diameter.

Reliability: Few moving parts.

Widespread Potential

The MicroBlower enables the use of simple, low-cost soil vapor extraction in shallower areas than
previously considered possible. One of the greatest potentials for MicroBlower is in treatment polishing of
an area treated by an expensive, large blower system that still has residual contamination. Installation of
an economical MicroBlower system to finish the cleanup at greatly reduced costs, allows owners to use
their larger system in other areas or sites where they can produce greater returns. The MicroBlower also
can remediate sites that are smaller than the capacity of typical, large blower systems.
Copyright © 2013 Tersus Environmental Systems, LLC. All Rights Reserved.
Rev: 1 May 2013

At a Glance

ü Long operating life
ü Robust construction
ü Powered by renewable sources of energy
ü Ideal for remote applications
ü Lower carbon footprint and O&M expenses than ASVE
ü No trenching for ancillary infrastructure
ü Remediates shallow areas
ü Remediates vadose zone
ü Excellent for treatment polishing
ü Offers significant cost savings
ü Patented Technology

Cost Savings

The MicroBlower offers significant cost savings to the
groundwater remediation industry. Presently, there are no
regulations concerning the contaminants in the vadose zone.
However, if the vadose zone is not remediated, contamination
will migrate downward and contaminate / recontaminate the
groundwater. With the groundwater no longer in compliance,
responsible parties must bear the cost of remediating the groundwater. By installing the MicroBlower, the
risk of the groundwater being initially contaminated or recontaminated from the vadoze zone would be
significantly mitigated.

Verified Performance

During a 10-month period, one MicroBlower removed 234 pounds of volatile organic compounds from a
contaminated groundwater plume beneath a site in South Carolina.

About Us

What if we always settled for the first technology that came along?
Then we would have never gotten to where we are today.

We Develop & Market Innovative, Sustainable, Green Technologies. Tersus Environmental also provides
global sales management and marketing services for inVentures Technologies’ complete family of
groundwater remediation products based on the worldwide-patented Gas inFusion technology, which
allows for supersaturated levels of dissolved gas into liquids.

Innovative Sustainable Green Technologies
Tel: [phone] • [e-mail]
tersusenv.com • tersusenv.fr • tersusenv.es