7607_GreatOakMSWLF_Com_Leacktestinglocation_DIN26665_20160831

PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary

MICHAEL SCOTT
Director
Solid Waste Section

August 31, 2016

Ms. Sharon Y. Korleski, P.E.
S&ME, Inc.
301 Zima Park Road
Spartanburg, SC 29301

Re: Comment on the Proposed Leak Location Test on Landfill Base Liner System
Great Oak Landfill, Randolph County Regional MSWLF
Randolph County, North Carolina
Permit No. 7607-MSWLF-2015, Document ID No. (DIN) 26665

Dear Ms. Korleski:

On July 20, 2016 S&ME, Inc. (S&ME), on behalf of Waste Management of Carolinas, Inc. (Waste
Management), sent the Solid Waste Section (the SWS) an electronic copy of a letter (DIN 26623) via
email responding to the SWS comments (DIN 26273) dated June 17, 2016 on the proposed leak
location test on landfill baseliner system at the above-referenced landfill (DIN 26166). The hard
copy of the response letter was received by the SWS on July 28, 2016. After completing a review of
the letter and conducting additional literature reviews and investigations, the SWS respectfully
disagrees with the proposed leak location testing on the secondary geomembrane liner layer. This
conclusion is made based on the following:

1. North Carolina General Statute (NCGS) 130A-295.6(h)(1) requires any sanitary landfill that
has “a geomembrane base liner system shall be tested for leaks and damage by methods
approved by the Department that ensure that the entire system is evaluated.” This is
additional technical requirement for constructing and operating a new (“green field”) sanitary
landfill in the State of North Carolina became effective August 1, 2007. Although the above-
mentioned law does not specifically define the “entire system” as either a single-composite
liner system or a double-composite liner system, the SWS interprets this law to be applicable
to both single or double-composite liner systems. Its purpose is to further enhance the
protection of human health and environment, which is consistent with the intentions and
contexts stated in the thirty (30)-year Franchise Agreement (SECTIONs 11 & 14) between
Randolph County and Waste Management and the Special Use Permit (II. Conclusions Of
Law) issued by the Randolph County Planning Board.

The State of North Carolina, among other states in this country as mentioned in the July 20,
2016 letter, is aware of the base liner system of a landfill being the only barrier between
leachate generated from the disposed wastes and the local groundwater resources.
Conducting leak location testing on the landfill base liner system, in additional to other rule-
Ms. Sharon Y. Korleski, P.E.
August 31, 2016
DIN 26665
Page 2 of 4

required testing requirements on liners as specified in the approved construction quality
assurance and construction quality control (QA/QC) program helps to further confirm and
verify the integrity of installed geosynthetic liners.

2. Waste Management proposed the alternative landfill baseliner system for the Great Oak
Landfill instead of the prescribed landfill base liner systems as specified in North Carolina
Solid Waste Management Rules 15A NCAC 13B .1624(b)(1)(A)(i), (ii), or (iii). The selected
landfill base liner system consists of the following from top to bottom:
At the landfill cell floor area - double- composite liner layer
 Two feet of protective cover soil;
 Leachate collection system (LCS) geocomposite drainage layer;
 Primary 60-mil textured HDPE geomembrane;
 Leak detection system (LDS) geocomposite drainage layer;
 Secondary 60-mil textured HDPE geomembrane
 Geosynthetic clay liner (GCL);
 Subgrade soil or compacted structural fill soil.

At the sump area – triple-composite liner system
 Two feet of protective cover soil;
 Leachate collection system (LCS) geocomposite drainage layer;
 Primary 60-mil textured HDPE geomembrane;
 Leak detection system (LDS) geocomposite drainage layer;
 Tertiary 60-mil textured HDPE geomembrane;
 Geosynthetic clay liner (GCL);
 Secondary 60-mil textured HDPE geomembrane
 Subgrade soil or compacted structural fill soil.

Replacing the granular drainage material (gravel or rock) by geocomposite drainage material
in the LCS and LDS may reduce potential puncture damage on geosynthetic material due to
sharp granular material throughout the construction and operation of the landfill. However,
the risks to damage liner system resulting from (1) default in welds/seams and (2) puncture
from operating heavy equipment for spreading and compacting the two-feet protective cover
soil over the installed geosynthetic liner system exist. According to literatures and case
studies, the latter contributes to the primary (approximately 70%) damage to the installed
liner system. The leak location testing on the secondary composite liner layer prior to
completion of the entire landfill baseliner system will not provide any assurance that the
constructed primary composite liner layer will not be damaged during the installation of the
two-foot protective cover soil.

3. The argument to support the proposal of leak location testing on the secondary composite
liner layer is if the primary composite liner layer fails, the secondary composite liner layer
Ms. Sharon Y. Korleski, P.E.
August 31, 2016
DIN 26665
Page 3 of 4

coupling with the function of the LCS & LDS can be served as the back-up primary
composite liner system. Consequently, the constructed double composite liner system will be
functioning as a (much thicker) single composite liner system. This argument or assumption
that has never been described in the approved permit application (DIN 23916) and the
supplement (DIN 25125) breaches:
 The original purpose of this landfill base design, a more conservative approach, as
stated in your July 20, 2016 letter “which exceeds the minimum NC regulatory
requirements…” and
 The public trust documented in the Public Meeting conducted on March 7 and 8,
2013 for considering the Special Use Permit Application, I. Findings of Fact, B - The
use will not material endanger the public health if located where proposed and
developed according to the plans as submitted and approval.

According to Dr. David E. Daniel’s comments on the research report titled “a Study of the
Merits and Effectiveness of Alternate Liner Systems at Illinois Landfills” by Joyce Munie,
P.E. date January 2003, he said “… In my view, the key issue to protect groundwater from
landfills is not how many liners are used, but assurance that the liners are properly
constructed and construction verified through a very thorough construction assurance
program…” His comment consistently coincides with those stated in his other QA/QC
publications such as “Waste Containment Facilities – Guidance for Construction Quality
Assurance and Quality Control of Lined and Cover System and “Assessment and
Recommendations for Improving the Performance of Waste Containment Systems,” which
are coauthored with Dr. Robert M. Korner.

4. According to research done and concluded by G.N Richardson (1996) and Daniel et. Al.,
(2002) the geotextile and geocomposite materials are able to serve as a cushion to protect the
underlying geosynthetic liner (for this case the primary liner layer), but the loading
conditions for the research was carefully controlled and prepared without considering the
aggressive operation of equipment and machinery including machine sharp turns on the liner
system or intrusion of dozer blade which conclusively contribute to the liner damage. This
research bolsters the argument for the necessity of leak location testing as one part of the
QA/QC testing in landfill projects.

5. According to the literatures/specifications generated from geosynthetic manufacturers and
knowledge/experience accumulated from the waste industries, the installed geocomposite
drainage layer will provide limited cushion over the installed geosynthetic liner while a
heavy construction equipment/machinery installs the protective soil layer over the
geocomposite drainage layer. During the period of installing the protective cover layer, the
following are common practices to protect the geocomposite drainage layer and the
underlying geosynthetic liner material, but are not specifically included in the Specification -
Ms. Sharon Y. Korleski, P.E.
August 31, 2016
DIN 26665
Page 4 of 4

Section 31.2323.13, Backfill. We trust the contractor and onsite QA persons are familiar with
them and will include them in their practices.
 The deployed geocomposite drainage layer should be covered in a timely manner,
normally within 30 days of installation, to limit UV light damage.
 Low-tire-pressure equipment or a tracking equipment shall be properly selected and
used to finish site slopes or grades and to distribute the selected earthen material over
the geocomposite material.
i. A layer of soil material, a minimum of 12-inches thick, is required to separate
the equipment from the geocomposite drainage layer to prevent damage.
ii. No sharp turning of tracked equipment on the protective cover layer is
allowed.
iii. No material shall be dumped down a slope. On sloped areas (6 [Horizontal] :
1 [Vertical] or steeper), protective soil cover should be placed and spread
from the bottom up unless otherwise approved by the Engineer.
 Any hauling equipment operating over geosynthetics should have a minimum of
three (3) feet of separation between vehicle wheels and the geocomposite drainage
material.
Please provide a liner sampling protocol (including typical example of the testing result report) that
at a minimum tests the upper most layer after completion of construction and placement of the
protective cover. If you have further questions on the comments, please contact me at 919-707-8251
[e-mail] or John Murray at 252-808-2808x 204 [e-mail].

Sincerely,
Ming-Tai Chao, P.E.
Environmental Engineer
Division of Waste Management, NCDEQ

cc:
Paxton Arthur, P.E., Randolph County
John Workman, Waste Management
Steve Lamb, P.E. SCS Engineers
Ed Mussler, P.E, Permitting Branch Supervisor
John Murray, P.E., DWM
John Patrone, DWM
Deb Aja, DWM
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