6013_GreenwayNorthMeckCDLF_20180301_WQMPConsultantResponse_FID1087412

March 1, 2018

Ms. Jackie Drummond
Compliance Hydrogeologist
Division of Waste Management - Solid Waste Section
North Carolina Department of Environmental Quality
Asheville Regional Office
2090 US Highway 70
Swannanoa, NC 28778

Dear Jackie:

Subject: North Mecklenburg C&D Landfill – Permit 60-13
Greenway Waste Solutions of North Meck, LLC
Water Quality Monitoring Plan
CEC Project 111-370.001

Introduction
On behalf of Greenway Waste Solutions of North Meck, LLC (GWS), Civil & Environmental
Consultants, Inc. (CEC) prepared an updated Water Quality Monitoring Plan (DIN 28684) for the
North Mecklenburg C&D Landfill (Closed Phase I Area and Infill Area), which CEC initially
submitted as Appendix E in the Permit Modification Amendment Application to the NCDEQ Solid
Waste Section (Section) for review on August 31, 2017. In addition, CEC prepared an Assessment of
Corrective Measures report (DIN 28683) for the subject landfill facility, which CEC submitted to the
Section for review on November 17, 2017. The strategies outlined in the aforementioned documents
are based on unifying the presently separate water quality monitoring plans for the Closed Phase I
Area and Infill Area, and to re-establish the point of compliance monitoring wells to reflect the landfill
facility boundary based on the intent of Rule 15A NCAC 13B .0544, which have been requested in
these documents yet have not been approved by the Section.

The Section agreed to a meeting to discuss these matters that was held on February 16, 2018 and
attended by representatives of GWS, CEC, and the Section. During the meeting, Section
representatives indicated that the request for a permit modification was at an impasse until the
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

strategies and regulatory considerations requested for approval in the Water Quality Monitoring Plan
(WQMP) were resolved. To move this matter toward a resolution, the Section requested that GWS
prepare a letter providing the rational for the strategies and regulatory considerations outlined in the
updated WQMP for review by the Section. This letter has been prepared to serve that purpose.

Background
In Appendix E of the Permit Modification Amendment Application, CEC updated the WQMP for
the North Mecklenburg C&D Landfill, which modifies the previous Proposed Monitoring Plan
prepared by Ecological Services, Inc. dated February 2, 1995 for the Closed Phase I Area and
Water Quality Monitoring Plan prepared by EnviroPro, P.C. dated January 2010 for the Infill
Area. CEC prepared the updated WQMP for the North Mecklenburg C&D Landfill to include
assessment monitoring requirements and activities that have been implemented and are on-going
at the landfill facility since benzene and vinyl chloride were detected in groundwater samples in
October 2012.

GWS operates the aforementioned Closed Phase I and Infill Areas at the landfill facility under
separate regulatory requirements. Permitted in 1993, GWS maintains the Closed Phase I Area
under the “old” .0500 Rules. Permitted in 2002, GWS operates the Infill Area under the current
.0500 Rules that became effective January 1, 2007. As depicted in Figure 1, the Closed Phase I
Area comprises the southern half of the landfill facility and the Infill Area comprises the northern
half of the facility. An unnamed stream tributary to Cane Creek separates the two landfill areas.
Cane Creek runs parallel to and lies south of the Closed Phase I Area. As shown in the attached
Figure 2, groundwater moving away from the Infill Area and northern half of the Closed Phase I
Area either discharges to the tributary stream or flows eastward beneath the stream until it passes
beneath the eastern landfill property boundary and ultimately discharges to Cane Creek. The
intervening tributary stream is routinely sampled and no significant surface water impacts have been
shown by the historical surface water monitoring data. Prior to recent data quality evaluations by
several analytical laboratories in 2016-2017, vinyl chloride in excess of the 2L Standard was reported
in monitoring wells situated in the vicinity of the confluence of the tributary stream and Cane Creek
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

on the east-central perimeter of the landfill facility. Since the data quality testing, vinyl chloride has
not been reported in well samples from this site area above the laboratory reporting limits.

The original WQMPs for the subject landfill areas specified downgradient monitoring wells to be
placed and monitored in both landfill areas along the centrally located tributary stream. It is our
understanding that at the time the permit was issued for the Infill Area, the Section reasoned and
GWS concurred that placement and routine monitoring of downgradient monitoring wells north of
the internal stream tributary were needed should groundwater contamination be detected in order to
assign cause to the contributing landfill area. These particular wells appeared reasonable and
warranted until it was determined that both landfill areas are sources of VOC contamination. At this
point, the monitoring wells along the tributary stream monitor groundwater conditions internal to
the landfill facility. This internal monitoring area is more related to a "review boundary" than it is a
point of compliance boundary.

Rule 15A NCAC 02L .0108 states a review boundary is established around any disposal system
midway between the compliance boundary and the waste boundary. When the concentration of a
contaminant equals or exceeds the standard at the review boundary as determined by monitoring,
this Rule requires the permittee to take action in accordance with Rule 15A NCAC 02L .0106
(c)(2)(A), which appears to be cited in the Rule in error. However, Rule 15A NCAC 02L .0106(d)(1)
requires any person conducting or controlling an activity which is conducted under the authority of
a permit issued by the Division and which results in the exceedance of a 2L Standard at or beyond a
review boundary, shall demonstrate through predictive calculations or modeling that natural site
conditions, facility design, and operational controls will prevent a violation of standards at the
compliance boundary; or submit a plan for alteration of existing site conditions, facility design, or
operational controls that will prevent a violation at the compliance boundary, and implement that
plan upon Section approval. CEC has submitted a plan proposing operational controls (i.e. landfill
gas extraction) to address the groundwater VOC exceedances in this internal landfill area.

It appears that the intent of 15A NCAC 13B .0544 is to utilize relevant point of compliance wells to
timely evaluate groundwater quality at a suitable interception distance from an adjacent landfill
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

property boundary. A significant number of the internal monitoring wells placed along the tributary
stream are located less than 50 feet from the respective waste disposal area and at a considerable
distance from the nearest property boundary. Thus, such wells are monitoring internal portions of
the landfill facility and are not suitably located to meet the intent of point of compliance. The
updated WQMP specifies the site monitoring wells that are suitable for point-of-compliance
boundary monitoring and those that are better suited for review boundary. While delineating the
extent of the groundwater contaminants, GWS installed 23 assessment wells, which are now a part
of the assessment monitoring program. Please note that GWS does not propose that monitoring be
terminated in any on-site groundwater monitoring well until such time that the monitoring data
confirms groundwater quality has been restored to its natural state. GWS, that is, proposes to
continue monitoring during the implementation of the proposed active remedial measures.

Regulatory Considerations
Since the Infill Area was permitted in 2002 under the current .0500 Rules, GWS has performed
separate water quality monitoring and regulatory reporting for the older Closed Phase I Area and
more recently permitted Infill Area. The water quality monitoring requirements differ for each
landfill area, and the Section has required separate monitoring plans and semi-annual water
quality monitoring reports for each landfill area. In addressing on-going and pending corrective
action at the landfill facility, we anticipate that there will not be a distinct outcome or response
relative to a specific landfill area. For these regulatory considerations, GWS is requesting that
the two landfill areas be combined under a single WQMP and to re-establish the point of compliance
monitoring wells to reflect the landfill facility boundary.

In accordance with 15A NCAC 13B .0544(b)(1), the purpose of the updated WQMP is to identify
the current monitoring network, methods, and procedures to be used to effectively monitor
background and downgradient point of compliance water quality in the uppermost aquifer at the
subject site. In determining the relevant point of compliance at the subject facility, Rule 15A
NCAC 13B .0544(b)(1)(B) allows the owner and operator to make recommendations for
consideration by the Division based upon 1) site hydrogeology; 2) proximity and withdrawal rate
of the ground-water users; 3) existing groundwater quality including other contaminant sources
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CEC Project 111-370.0001
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March 1, 2018

and their cumulative impacts on the ground water; 4) whether the ground water is currently used
or reasonably expected to be used for drinking water; 5) public health, safety, and welfare effects;
and 6) practicable capability of the owner and operator. These conditions are briefly described
in the following paragraphs.

Site Hydrogeology
Groundwater moves beneath both landfill areas discharging either to the tributary stream or to
Cane Creek to the south or east as predicted by the Piedmont "slope aquifer system" described by
LeGrand in LeGrand, H.E. 2004. Master conceptual model for hydrogeological site
characterization in the Piedmont and Mountain region of North Carolina: a guidance manual.
North Carolina Department of Environment and Natural Resources, Division of Water Quality,
Groundwater Section. This particular site hydrogeologic setting allows for adequate water quality
monitoring at assigned point of compliance wells located along the perimeter of the landfill
property as proposed in the updated WQMP. The routine monitoring of internal review wells is
useful to evaluate internal landfill conditions; however, internal wells may indicate groundwater
impacts that never migrate to the proposed facility point of compliance. Thus, decision-making
regarding corrective action should be based upon groundwater quality conditions identified at
downgradient point of compliance monitoring wells that are located relevant to the landfill property
boundaries.

Area Groundwater Use
In 2014, GWS provided a public water supply to three adjacent residences situated at the southern
boundary of the landfill facility. Private water supply wells formerly operated at these residences
were made inactive. As depicted on Figure 3, other known area wells are located hydraulically
upgradient of the facility or are located at distances greater than 1,300 feet from the closest landfill
boundary on the opposite side of Cane Creek.

Existing Area Groundwater Quality
Other than the aforementioned neighboring residences that were provided public water by GWS,
we are not aware of other area water supply wells that are potentially threatened by observed
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

groundwater conditions observed at the GWS landfill facility. Other area water supply wells
appear to be more threatened by impacts from the neighboring Mecklenburg County Holbrooks
Road (unlined MSW) Landfill (Solid Waste Facility Permit #60-02) than the subject C&D landfill.

Expectation of Groundwater Use as Drinking Water
Mecklenburg County Government adopted the Mecklenburg County Groundwater Well
Regulations in October 2004. Before issuing a water supply well construction permit, the County
conducts a field investigation to evaluate the topography, landscape position, available space, and
potential sources for groundwater contamination on or around the site on which a water supply
well is to be located. Should the County determine a water supply well cannot be constructed in
compliance with the subject regulations, it will issue a written notice of denial of a construction
permit. Further, the regulations require the County to establish an Area of Regulated Groundwater
Usage (ARGU) when the groundwater standards as referenced in 15A NCAC 2L .0202 are
exceeded at a property.

The tax parcel occupied by the North Mecklenburg C&D Landfill is shown as a Mecklenburg
Priority List (MPL) site on the Well Information System 4.0 map, as is the adjacent Mecklenburg
County Holbrooks Road (unlined MSW) Landfill. Per the regulation, the ARGU is to extend 1,500
feet around the property boundary of the contamination site, if the source area of the contaminant
is unknown and the contaminant plume has not been defined or partially defined. New and existing
water supply well use is regulated within the ARGU. If public water is available, a new well will
not be permitted 1,000 feet or less from the property boundary of the contamination site, if the
source area of the contaminant is unknown and the contaminant plume has not been defined or
partially defined. A new or existing well permitted within the ARGU will require initial water
sampling and biannual sampling for the contaminants of concern, and treatment for identified
contaminants.

These regulations allow the County to review new and existing groundwater wells with respect to
known mapped contaminated sites for public safety. Given that the GWS and Mecklenburg
County Landfills coexist in the same general area, it is not reasonably expected that area
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

groundwater will be used in the future for drinking water. Recent land development pressures in
the area are making public water more readily available to local residences.

Public Health, Safety, and Welfare Effects
The public health, safety, and welfare will not be jeopardized by our request to provide adequate
point of compliance monitoring of the landfill facility under one consolidated landfill monitoring
plan. GWS will undertake appropriate active corrective measures, including landfill gas
extraction, in areas where point of compliance monitoring data indicate significant groundwater
quality impacts. In fact, GWS has proactively implemented an active landfill gas extraction system
that we believe will improve groundwater quality at the landfill facility. As noted above,
Mecklenburg County regulates existing and new water supply well use in the vicinity of the subject
landfill.

Practicable Capability of the Owner and Operator
GWS is capable of addressing appropriate corrective actions that are necessary to protect human
health and the environment. In fact, GWS has been proactive and expended considerable financial
resources in undertaking several precautionary measures to reduce potential human health risks
including the provision of public water to three neighboring residences. Because the VOC
contamination observed in site groundwater appears to be largely the result of landfill gas impacts,
GWS has installed a landfill gas extraction system that is currently operating in the Closed Phase
I Area, which has been expanded to other areas. In addition, GWS has installed a new landfill gas
extraction system in the Infill Area that was activated the week of February 26, 2018.

Revisions to Recently Submitted Updated Water Quality Monitoring Plan
On behalf of GWS, CEC has revised the updated WQMP (DIN 28684) in response to the Section’s
comments in a January 10, 2018 letter (DIN 28715) and justification presented in this letter. The
revised WQMP is attached under separate cover. The revised WQMP proposes to combine both
the active Infill Area and the Closed Phase I Area into one single entity for monitoring purposes.
Revisions have been made to the list of specified point of compliance (POC) wells and review
boundary wells in Tables 1 and 2 of the revised WQMP. In addition, Figure 2 has been revised to
Ms. Jackie Drummond - NCDEQ
CEC Project 111-370.0001
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March 1, 2018

include POC wells MW-4D-1 and MW-6D-1 that were inadvertently omitted in the figure, and
has been updated to include three new surface water sampling locations along Cane Creek to the
south and southeast of the landfill facility.

Conclusions
Based on the information provided, we believe that combining the separate monitoring plans for the
Closed Phase I Area and Infill Area into a unified updated facility WQMP meets the intent of 15A
NCAC 13B .0544(b)(1), which is to provide a monitoring network, methods, and procedures to
effectively monitor background and downgradient point of compliance water quality in the
uppermost aquifer at the subject site.

Thank you for your consideration of this request. If you have any questions or comments, please feel
free to contact me at [phone].

Sincerely,

CIVIL & ENVIRONMENTAL CONSULTANTS, INC.

Ed Stephens, PG Scott L. Brown, P.E.
Senior Project Manager Vice President

Attachments
Figure 1 Site Map
Figure 2 2017 Spring Groundwater Potentiometric Map
Figure 3 Area Water Supply Well Location Map
EXPANSION AREA 2
PHASE 1, 2 AND 3
ACTIVE C&D
LANDFILL CELLS
EXPANSION AREA 1
CLOSED C&D
LANDFILL CELL
CLOSED C&D
LANDFILL CELL
INFILL EXPANSION
AREA ACTIVE C&D
LANDFILL CELL
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DESCRIPTIONDATENOREVISION RECORDDATE:DWG SCALE:DRAWN BY:CHECKED BY:APPROVED BY:PROJECT NO:FIGURE NO.:SITE MAP111-370.0001AS NOTEDFEBRUARY 2018JKS/PABEHSEHS1GREENWAY WASTE SOLUTIONS OFNORTH MECK, LLCNORTH MECKLENBURG LANDFILLHUNTERSVILLE, NCNORTH
www.cecinc.com1900 Center Park Drive - Suite A - Charlotte, NC 28217Ph: 980.237.0373 · Fax: [phone]REFERENCE
LEGEND
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DESCRIPTIONDATENOREVISION RECORD333 Baldwin Road · Pittsburgh, PA 15205412-429-2324 · 800-365-2324www.cecinc.comDATE:DWG SCALE:DRAWN BY:CHECKED BY:APPROVED BY:PROJECT NO:ATTACHMENT:2017 SPRINGGROUNDWATER POTENTIOMETRIC MAP111-370.0001AS NOTEDFEBRUARY 2018PNP/PABEHSSLB2GREENWAY WASTE SOLUTIONSAT NORTH MECK, LLCNORTH MECK LANDFILLHUNTERSVILLE, NCNORTH LEGEND
NOTES
DATE:DWG SCALE:
DRAWN BY:CHECKED BY:APPROVED BY:
PROJECT NO:
FIGURE NO.:
AREA WATER SUPPLY WELL LOCATION MAP
111-370.0011" = 1,000'NOVEMBER 2017
CTH MK EHS 3
GREENWAY WASTE SOLUTIONS
AT NORTH MECK, LLC
NORTH MECK LANDFILL
HUNTERSVILLE, NORTH CAROLINA
REFERENCE
www.cecinc.com
1900 Center Park Drive - Suite A - Charlotte, NC 28217
Ph: 980.237.0373 · Fax: [phone]
NORTH