7607-GreatOakMSWLF_response_comment_constructiondocument_DIN28570_20171020

1
Chao, Ming-tai
From:Lamb, Steve <[e-mail]>
Sent:Friday, October 20, 2017 1:23 PM
To:Chao, Ming-tai
Cc:Workman, John
Subject:[External] FW: response to Ming - RE: Cell 2 Construction, Great Oak Landfill, 76-07, DIN
28530
Attachments:Great Oak LF Cell 2 Constrcution Drawings_revised_10-19-20.pdf
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Ming

Our responses to your comments are shown in red below. Attached are the revised construction drawings. A hard copy
will also be sent out today.

See you at the pre-con meeting on Thursday.

Steve

From: Chao, Ming-tai [mailto:[e-mail]]
Sent: Monday, October 09, 2017 4:36 PM
To: Workman, John <[e-mail]>; Lamb, Steve <[e-mail]>
Cc: Mussler, Ed <[e-mail]>; Glenn, Albert <[e-mail]>; Patrone, John
<[e-mail]>; Moore, Daniel <[e-mail]>; Ritter, Christine <[e-mail]>
Subject: RE: Cell 2 Construction, Great Oak Landfill, 76-07, DIN 28530

Gentlemen:

DIN 28530
The Solid Waste Section(the SWS) completes a review of the following documents:
1. The “minor permit modification” document (DIN 28421) and the 10/04/2017 responses (DIN 28522) to
the 09/08/2017 comments (DIN 28437).
2. Project Manual and a set of construction drawings for Phase 1 - Cell 2 of the Great Oak Landfill (DIN
28504). The Project Manual has incorporated the revision of the QA/QC and specifications described in
the “minor permit modification” document.
Based on the review, the SWS determines that requested revisions stated in the “minor permit modification”
document (DIN 28421) and responses (DIN 28522) are acceptable. Waste Management of Carolinas, Inc.
(WM) shall provide an addendum to the Project Manual; specifically, in the Table 0519.26-C, the following
specifications must be updated: We agree.
1. The transmissivity of drainage geocomposite layer used in LDS system must be greater than 1 x 10-4
m3/m/sec as specified in the response letter (DIN 28522).
2. The Note 1 of the Table 0519.26-C shall state that the test at
(a) normal load of 21,120 pound per square feet (psf) and
(b) the hydraulic gradient 0.1 ft/ft (DIN 28522).
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Because the change of the transmissivity of drainage geocomposite layer in the LDS system, the action leakage
rate (ALR) in Cell 2 will be reduced from the original approved 182 gallon per day per acre to the new ALR of
138 gallon per day per acre. This revision will be incorporated to the Permit Approval to Operate for Phase 1,
Cell 2. Please note that this revision will not change the ALR (182 gallon per day per acre) for Phase 1, Cell 1
of the landfill.

The SWS has several comments or concerns on the construction drawings for Cell 2, which stated below:

1. (Drawing No. 2A of 10)
i. North Stormwater Channel can’t be located at Detail 2 on Drawing No. 8B of 10. It is likely that
Detail 2 on Drawing No. 8B is a typo. No. Detail 2 on Sheet 8B is correct for North
Channel. The riprap detail for the channel is illustrated on Detail 2 on Sheet 8A.
ii. Will North Stormwater Channel be lined by either riprap as shown on or turf reinforced
mat? Please clarify. Rip rap will be placed in the bottom of the channel as shown in Detail 2 on
Sheet 8A. The orange shaded area on Sheet 2A identifies where turf matting will be used.
iii. Please confirm the channel dimensions. It is evident that has different dimensions between the
riprap lined channel (Detail 2 on Drawing No. 8A), the turf reinforced one (Detail 2 on Drawing
No. 8B) and the one shown on Detail 5 of Drawing No. 7. The channel dimensions shown on
Detail 2/Sheet 8B and Detail 5/Sheet 7 are the same (4ft bottom trapezoidal channel with 3:1
sideslopes). The riprap detail on Detail 2/Sheet 8A also shows a 4 ft bottom width.
iv. Should there be an energy dissipater in the end of North Stormwater Channel reaching the 36-
inch-diameter culvert pipe? Pipe inlet protection currently exists in front of the 36”
culvert. This was inadvertently left off the drawing. It has been added to Sheet
2A. Furthermore, the contractor shall inspect the existing pipe inlet protection and replace if
necessary, in accordance with the Erosion & Sediment Control Plan.

2. (Drawing No. 3 of 10)
i. Riprap Lined Channel (see Detail) should be named as Check Dam as shown Detail 5 Drawing
No. 8 of 10. Drawing 3 was revised to reference Detail 2/Sheet 8A and Detail 2/Sheet 8B.
ii. How many check dam will be constructed along North Stormwater Channel? What is the
distance between the dams? Check dams will be not be used. Detail 5/Sheet 8 has been deleted.

3. (Drawing No. 3A of 10) According to the drawings there is a significant amount of bedrock potentially
to be excavated and removed in the course of constructing Cell 2. Please prepare the rock blasting plan
for review and approval. The Contractor shall prepare a Blasting Plan prior to blasting.

4. (Drawing No. 5 of 10)
i. The detail of Detection System Pipe Cleanout (adjacent to the Cell 2 sump/pump control panel)
is likely referenced to the incorrect drawing. The correct drawing is Detail 1 on Drawing No.
8. This has been corrected on the Revised Construction Drawings.

ii. Since the entire shaded area will be installed with tertiary 60-mil HDPE liner. The liner system
detail (double composite liner system) underneath the LCR pipe referred in Detail 7 on Drawing
No. 8 is incorrect. Detail 7/Sheet 8 has been corrected.

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5. (Drawing Nos. 5 & 6 of 10)
i. Two LCR rib pipes (run north to south) cross the LCR corridor/header (run west to east). Please
provide details of piping installation at the cross points. We will request shop drawings from
contractor for this issue. Shop drawings will be submitted to SWS.
ii. Since the entire shaded area will be installed with tertiary 60-mil HDPE liner. The liner system
detail (double composite liner system) underneath the LCR pipe referred in Detail 7 on Drawing
No. 8 is incorrect. Detail 7/Sheet 8 has been corrected.

6. (Drawing No. 8 of 10) Please specify the clear distance (height) from the pipe cleanout (both LDS and
LCR piping) to the existing grade. Since the pipe cleanout will be located immediately adjacent to
drainage ditches, adequate clearance / height must be provided to prevent piping from being flooded, via
pipe cleanout, by surface water conveyed by nearby the drainage features during the extreme storm
events. Detail 1 and 2 on sheet 8 have been revised to show a 2-ft distance above finished grade.

7. (Drawing No. 9 of 10)
i. What is the thickness of the #5 drainage aggregate layer inside the LCS sump? The thickness is
4.5 ft as shown on Detail 3/Sheet 9. The dimension was also added to Detail 2/Sheet 9.
ii. What are the design capacity (volume) of the sump – LCS and LDS? The pump activation depth
is assumed as the sump depth for calculating each LCS and LDS sump capacity. The LCS
capacity is about 300 ft3 (20’x15’x1’). Assuming a porosity of 0.3 equates to about 670
gallons. The LDS sump capacity is about 200 ft3 (20’x10’x1’), or 450 gallons.
iii. The invert elevations of the riser pipe of LCS and LDS sumps must be surveyed and noted in the
as-built drawings. We agree.

8. (Drawing No. 10 of 10) To increase the height of the vault or ring of the manhole should be considered
by adding a riser or an extension to prevent the manhole or vault from flood water from the nearby
drainage features. The gaskets are required to properly seal the hatches of the manholes. We agree.

Please contact myself if you have any questions on the above-mentioned comments/concerns. Thank you and
have a wonderful evening.

Ming Chao
Ming-Tai Chao, P.E.
Environmental Engineer
Permitting Branch, Solid Waste Section
NCDEQ, Division of Waste Management
(Mailing Address)
1646 Mail Service Center
Raleigh, NC 27699-1646

(Street Address)
Green Square, 217 West Jones Street
Raleigh, NC 27603
Tel. [phone]
[e-mail]
http://portal.ncdenr.org/web/wm/sw
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E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.

From: Chao, Ming-tai
Sent: Tuesday, September 26, 2017 4:04 PM
To: 'Workman, John' <[e-mail]>; Lamb, Steve ([e-mail]) <[e-mail]>
Cc: Mussler, Ed <[e-mail]>
Subject: Cell 2 Construction, Great Oak Landfill, 76-07

Gentlemen:

Please provide me a copy of the set of construction drawings for Phase 1 - Cell 2 and the bid package when you finalize
them; so I may provide my side suggestion(s) in the pre-construction meeting or earlier in due time. I know it is quite
early to make this request, but I need do it now before I forget it. Thanks for help.

Ming Chao

From: Chao, Ming-tai
Sent: Friday, September 08, 2017 12:29 PM
To: 'Lamb, Steve' <[e-mail]>; 'Glenn, Albert' <[e-mail]>
Cc: Mussler, Ed <[e-mail]>; 'Workman, John' <[e-mail]>
Subject: Comments on Permit modification, Great Oak Landfill, 76-07, DIN 28437

Gentlemen:

The Solid Waste Section completes a review of the “permit modification” document and has some comments on
the request. The comments are stated below:

DIN 28437
1. (Exhibit A - Estimate the long-term hydraulic transmissivity for LCS geocomposite drainage (GD)
material) Please explain why the reduction factors are changed from the original ones. It is noted that if
the original reduction factors were used in the calculation of hydraulic transmissivity for LCS GD and
other data used in the HELP model are the same – 0.25-inch thick GD with saturated hydraulic
conductivity of 1.4 cm/sec. Then, the T minimum = 8.89*10-5 *2*2*1.5*1.1 = 5.86*10-4 m2/sec, which
is greater than the revised one 4.2 *10-4 m2/sec. Considering uncertainties involved in the GD design and
the impossibility to repair the LCS system should any clog occur, the conservative design approaches
should be considered.

2. (Exhibit A - Estimate the long-term hydraulic transmissivity for LDS GD material)
i. Please provide the reference of the hydraulic gradient of 0.1 ft/ft used in the transmissivity
calculation. Should the gradients of the landfill base floor (at least 2%) and side slope (33% for
the 3 to 1 side slope) be considered in the calculation?
ii. Please explain why the reduction factors are changed from the original ones. (referring the
Comment No. 1)
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iii. What is the thickness of the leachate head on the top of the secondary liner/ in the LDS for each
of four waste loading cases? How is the GD thickness for LDS (Technical Specification 31
0519.26) determined?
iv. Should a product that meet the specified transmissivity is available and approved to be used at
this landfill construction/operation, what is new Action Leakage Rate (ALR) will be? Please
also provide the detail calculation processes of the ALR.

3. (Exhibit B - Technical Specification 31 0519.26)
i. According to the data in the previously approved Engineer Plan - Appendix IV, the
geocomposite draining layers (LCR & LDS) of the base liner system of the landfill - Phase 1 will
subject to a normal stress up to 21,120 pound per square feet (psf) generated from the projected
280-feet-thick disposed wastes, Case 4 in the Tables 1-1 & 1-2. Therefore, Table 0519.26-C (the
revised Technical Specification 31 0519.26 page 7 of 10) shall specify the normal load of 21,120
psf at each test.

ii. The specified transmissivity of the new GD for the LDS is 5.1*10-9 m3/m/sec.
a. Has any landfill owned or operated by the Waste Management ever used this kind “drainage”
material in the LDS? If the response is yes, please provide the reference; if not, why the
specified GD should be used in the landfill.
b. Is there a GD product meeting the specification available in the market? Please provide the
manufacturer’s product data sheet.

4. (Exhibit D – Detail 9/D1) The proposed deletion of geomembrane rain flap from the detail is acceptable
only if the stormwater/leachate separation device will not be used in the new cell of the Phase 1.
Please contact me if you have any questions on these comments. Thank you and have a wonderful weekend.

Ming Chao
Ming-Tai Chao, P.E.
Environmental Engineer
Permitting Branch, Solid Waste Section
NCDEQ, Division of Waste Management
(Mailing Address)
1646 Mail Service Center
Raleigh, NC 27699-1646

(Street Address)
Green Square, 217 West Jones Street
Raleigh, NC 27603
Tel. [phone]
[e-mail]
http://portal.ncdenr.org/web/wm/sw

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.

6
From: Chao, Ming-tai
Sent: Tuesday, August 29, 2017 5:06 PM
To: 'Lamb, Steve' <[e-mail]>; Glenn, Albert <[e-mail]>
Cc: Mussler, Ed <[e-mail]>; Workman, John <[e-mail]>
Subject: RE: Permit modification, Great Oak Landfill, 76-07

Hi Steve. I got it and the document is uploaded to Laserfiche with a DIN 28431. Thanks.

Ming

From: Lamb, Steve [mailto:[e-mail]]
Sent: Tuesday, August 29, 2017 4:41 PM
To: Chao, Ming-tai <[e-mail]>; Glenn, Albert <[e-mail]>
Cc: Mussler, Ed <[e-mail]>; Workman, John <[e-mail]>
Subject: RE: Permit modification, Great Oak Landfill, 76-07

Ming:

Here it is.

Thanks

Steve Lamb, PE
Vice President
SCS Engineers
2520 Whitehall Park Drive, Suite 450
Charlotte, North Carolina 28273
Office – 704.504.3107
Direct - 704-916-1529
Mobile – 704.576.4731

From: Chao, Ming-tai [mailto:[e-mail]]
Sent: Tuesday, August 29, 2017 2:56 PM
To: Lamb, Steve <[e-mail]>; Glenn, Albert <[e-mail]>
Cc: Mussler, Ed <[e-mail]>
Subject: Permit modification, Great Oak Landfill, 76-07

Gentlemen:

The Solid Waste Section receives the hard copy of “Minor Permit Modification” for Great Oak Landfill today.
Please send in or forward me an electronic copy of the document so I can upload to the document tracking
system. Thanks.

Ming Chao
Ming-Tai Chao, P.E.
Environmental Engineer
Permitting Branch, Solid Waste Section
7
NCDEQ, Division of Waste Management
(Mailing Address)
1646 Mail Service Center
Raleigh, NC 27699-1646

(Street Address)
Green Square, 217 West Jones Street
Raleigh, NC 27603
Tel. [phone]
[e-mail]
http://portal.ncdenr.org/web/wm/sw

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.

Recycling is a good thing. Please recycle any printed emails.
EXISTING
CELL 1A
EXISTING
CELL 1B
FUTURE
CELL 3
FUTURE
CELL 4
FUTURE
CELL 5
FUTURE
CELL 7
FUTURE
CELL 6
DUKEENERGYEASEMENT DUKEENERGYEASEMENT2
1
1
3
2
PROPOSED
CELL 2
10.0 ACRES
LOD = 26 ACRES
1
ISSUED FOR CONSTRUCTION
DATE: 8/31/17
REISSUED: 10/19/17
SURVEY CONTROL POINT (BY WSP SURVEY)
NAME NORTHING EASTING ELEVATION
TRAV-102 728,000.08 1776129.76 748.25
TRAV-103 727,626.34 1,775,896.77 738.72
TRAV-171 76,595.59 1,778,136.64 546.63
TRAV-172 726,407.49 1,778,061.47 547.86
SCS ENGINEERS, PC2520 WHITEHALL PARK DRIVE, SUITE 450CHARLOTTE, NORTH CAROLINA 28273PHONE: [phone] FAX: [phone]AEROSION AND SEDIMENTCONTROL PLANGREAT OAK LANDFILLWASTE MANAGEMENT OF CAROLINAS, INC.3597 OLD CEDAR FALLS ROADCELL 2 CONSTRUCTIONRANDLEMAN, NORTH CAROLINA 27317