division of environmental quality (deq) - microsoft …...this construction quality assurance (cqa)...

1

Blue, Karen

To: Coker, CristinaSubject: RE: NEARSWMD Class 1 Landfill, Paragould, Arkansas Permit No. 0120-S1-R5; AFIN:

28-00077

From: Carpenter, Owen [mailto:[email protected]]Sent: Friday, November 16, 2018 9:29 AM To: Coker, Cristina Cc: Johnson, Charles; Jason Wolfenbarger ([email protected]); Bardella, Tony L Subject: NEARSWMD Class 1 Landfill, Paragould, Arkansas Permit No. 0120-S1-R5; AFIN: 28-00077

Good morning Ms. Coker!

Please find attached to this email supplemental information regarding the CQA Certification Report for Phase 4 2Bconstruction at the referenced site, in response to your NOD letter dated November 8, 2018. The NOD responseincludes a revised report narrative with replacement pages 8, 16 and 17. Please replace your file copy of thecertification report narrative with that attached. If you need us to prepare a full replacement CQA Report includingappendices, just let us know. Thank you for reviewing the report and we look forward to your approval of the cell foruse by the facility. Please let us know if you have any questions or need any additional information.

Thanks!Owen

F. Owen Carpenter, P.E., P.G.Environmental Dept. I Solid Waste ServicesTerracon Consultants, Inc.25809 I-30 South I Bryant, Arkansas 72022P (501) 847 9292 I F (501) 847 9210 D (501) 943 1020 I C (501) 622 [email protected] I www.terracon.com

Terracon provides environmental, facilities, geotechnical, and materials consulting engineering services delivered with responsiveness, resourcefulness, and reliability.

Private and confidential as detailed here (www.terracon.com/privacy-policy). If you cannot access hyperlink, please e-mail sender.

Rec’d Digitally

AFIN:_________________________

PMT#:_________________________ SW

DOC ID#:______________________ MD

TO:___________________________

By Karen Blue at 1:49 pm, Nov 19, 2018

28-00077

0120-S1-R5

74924

AC>FILE <KMB

Terracon Consultants, Inc. 25809 I-30 South Bryant, Arkansas 72022 P [501] 847 9292 F [501] 847 9210 terracon.com

November 16, 2018 Arkansas Department of Environmental Quality Office of Land Resources 5301 Northshore Drive North Little Rock, AR 72118-5317 Attention: Ms. Cristina Coker, Engineer P: (501) 682-0627 E: [email protected] Subject: Supplemental Information Regarding Phase 4-2B CQA Report Response to November 8, 2018 Notice of Deficiency NEARS Class 1 Landfill, Paragould, Arkansas Permit No. 0120-S1-R5; AFIN: 28-00077 ADEQ Doc ID: 74858, Reference Doc ID: 74773 Dear Ms. Coker: On October 29, 2018, Terracon Consultants, Inc. (Terracon) submitted a construction certification report for the construction of Phase 4-2B at the NEARS Class 1 Landfill, located in Paragould, Arkansas. We are in receipt of your Notice of Deficiency letter dated November 8, 2018. This letter is intended to provide the information requested and satisfy the requirements for obtaining approval to begin using Phase 4-2B for waste disposal operations. Below is a list of the NOD comments in bold followed by our response.

1. Not all the as-built topography drawings were included in this Certification Report. Please submit an as-built drawing for the subgrade elevations and top of the protective cover. Every drawing must meet the requirements under Arkansas Pollution Control and Ecology Commission (APC&EC) Regulation No. 22.428(i). Also, please include in every drawing a table showing the results of the survey points. Attachment A to this response letter presents additional as-built topography drawings that meet the requirements of Reg.22.428(i). Reg.22.428(i) does not indicate that multiple drawings to show subgrade, top of clay and protective cover surfaces are required, but does require the elevations at 50’ intervals. Elevations for all three surfaces are presented on the attached drawings.

NOD Response – NEARS Phase 4-2B CQA NEARS Class 1 Landfill ■ Paragould, Arkansas November 16, 2018 ■ Project No. 35177287

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Attachment A As-built Drawings

0 2040 40 80

10-10-2018

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DATE:

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DRAWING NO:

18021

OCTOBER 2018

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DRN: APP: JMLMJMLM

PO BOX 571 ▪ GENTRY, AR 72734 ▪ (479)238-3109

TOP OF SUBGRADE SURVEY COMPLETED 07-10-2018 TOP OF CLAY SURVEY COMPLETED 08-14-2018

0 2040 40 80

0 2040 40 80

CERTIFICATION

I hereby certify this drawing and the information shown

heron was taken from field surveys completed on:

Top of Subgrade - 07/10/2018

Top of Clay Liner - 08/14/2018

Top of Protective Cover - 10/08/2018

Measurements were made by me or under my supervision.

Horizontal and vertical locations are based on the

NEARSWMD Landfill Permanent Site Control Monuments

as provided by owner.

__________________________

Johnny M. L. Mason, Professional Land Surveyor #1579

Date: October 10, 2018

10-10-2018

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PROJECT NO.:

DRAWING NO:

18021

OCTOBER 2018

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PO BOX 571 ▪ GENTRY, AR 72734 ▪ (479)238-3109

Point #

1

2

3

Elevation

274.54

271.53

272.33

Northing

642619.11

641752.66

641353.35

Easting

1770449.23

1770908.91

1770276.24

Description

FIP CAP

FD REBAR CAP

FIP CAP

SURVEYOR'S NOTES

1. All liner grid point data shown in table are as-built surveyed points.

2. Leachate pipe was placed on top of liner system at the flowing of

cell; therefore, inverts were calculated by adding pipe thickness to

top of geomembrane liner elevations:

3. Positions are based on the landfills permit site control monuments

provided to surveyor and listed in the table below:

POINT TABLETOP OF PROTECTIVE COVER SURVEY COMPLETED 10-08-2018

NOD Response – NEARS Phase 4-2B CQA NEARS Class 1 Landfill ■ Paragould, Arkansas November 16, 2018 ■ Project No. 35177287


Attachment B Revised Certification Report Narrative

CQA Certification Report Phase 4-2B

Northeast Arkansas RSWMD Class 1 Landfill

Permit No. 0120-S1-R5 AFIN: 28-00077

October 2018

Project No. 35177287

Prepared For:

Northeast Arkansas RSWMD P.O. Box 753

Paragould, Arkansas 72451 (870) 239-5572

Prepared By:

Terracon Consultants, Inc. 25809 Interstate 30 South

Little Rock, Arkansas 72022 (501) 847-9292

Phase 4-2B CQA Certification Report Northeast Arkansas RSWMD ■ Class 1 Landfill October 2018 ■ Project No. 35177287


PROFESSIONAL ENGINEER’S CERTIFICATION “I certify to the best of my professional judgment that the bottom liner system and leachate collection system for Phase 4-2B of the NEARSWMD Class 1 Landfill (Permit No. 0120-S1-R5) was constructed in accordance with the permit drawings and narrative, and applicable Arkansas Department of Environmental Quality regulations, unless otherwise noted. This certification is contingent on the fact that all information supplied to the signatory authority, at the time of this certification is unquestionably accurate and was provided in good faith.”

10/26/2018

F. Owen Carpenter, P.E., P.G. Date Arkansas Professional Engineer No. 8653


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Table of Contents

PROFESSIONAL ENGINEER’S CERTIFICATION

1.0 INTRODUCTION ................................................................................................. 1

1.1 GENERAL ............................................................................................................................................................ 2

1.2 SITE DESCRIPTION ............................................................................................................................................. 2

1.3 PROJECT DESCRIPTION ..................................................................................................................................... 2

1.4 KEY PERSONNEL................................................................................................................................................ 5

2.0 DEVIATIONS FROM PERMITTED PLANS AND SPECIFICATIONS ...................... 6

3.0 SURFACE PREPARATION ...................................................................................... 6

4.0 CLAY LINER SYSTEM INSTALLATION .................................................................. 6

4.1 PROJECT SPECIFICATIONS ................................................................................................................................ 6

4.2 CONSTRUCTION PROCEDURES ......................................................................................................................... 6

4.3 PRE-CONSTRUCTION TESTING OF CLAY LINER MATERIAL ............................................................................... 7

4.4 CONSTRUCTION TESTING OF COMPACTED CLAY LINER MATERIAL ................................................................. 8

5.1 MANUFACTURER’S QUALITY CONTROL CERTIFICATES ................................................................................... 11

5.2 MATERIAL CONFORMANCE TESTING ............................................................................................................... 12

5.3 DEPLOYMENT OF GEOSYNTHETICS ................................................................................................................. 12

5.4 GEOMEMBRANE TRIAL SEAM MONITORING .................................................................................................... 12

5.5 GEOMEMBRANE SEAM MONITORING ............................................................................................................... 12

5.6 NON-DESTRUCTIVE SEAM TESTING AND REPAIR MONITORING ..................................................................... 13

5.7 DESTRUCTIVE SEAM STRENGTH TESTING ...................................................................................................... 13

6.0 LEACHATE COLLECTION SYSTEM AND PROTECTIVE COVER ....................... 13

6.1 LEACHATE COLLECTION PIPE .......................................................................................................................... 13

6.2 PROTECTIVE COVER SOIL ............................................................................................................................... 14

7.0 INTERFACE FRICTION TESTING ......................................................................... 16

List of Tables

Table 1 Clay Liner Materials Pre-construction Test Summary Table 2 Clay Liner Materials Construction Test Summary Table 3 Permeability Results Summary Table 4 Protective Cover Sand and Leachate Collection Gravel Test Summary Table 5 Interface Friction Test Summary

List of Figures

Figure 1 Site Location Map Figure 2 Site Layout Map


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Figure 3 Clay Liner – Lift 1 Figure 4 Clay Liner – Lift 2 Figure 5 Clay Liner – Lift 3 Figure 6 Clay Liner – Lift 4 Figure 7 Geomembrane Panel Layout

List of Appendices

Appendix A As-Built Drawings Appendix B Daily Project Field Records Appendix C Clay Liner Material Pre-construction Test Results Appendix D Clay Liner Material Construction Test Results Appendix E Field Moisture/Density Test Results Appendix F Clay Liner Permeability Test Results Appendix G Geosynthetic Installer’s Resumes Appendix H Geomembrane Manufacturer’s QC Certificates Appendix I Geomembrane Conformance Test Results Appendix J Geosynthetics Inventory Listing Appendix K Geomembrane Equipment Calibration Log Appendix L Subgrade Acceptance Certificates Appendix M Geosynthetics Daily Deployment Logs Appendix N Geomembrane Trial Weld Summary Appendix O Geomembrane Panel Seaming Summary & Non-Destructive Test Log Appendix P Geomembrane Destructive Test Log Summary and Laboratory Test Results Appendix Q Geomembrane Repair Log Summary Appendix R Leachate Collection System Material Testing Appendix S Interface Friction Testing Appendix T Project Photographic Log


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1.0 INTRODUCTION This Construction Quality Assurance (CQA) Certification Report summarizes activities performed by Terracon Consultants, Inc (Terracon) during the construction of the bottom liner system, leachate collection system, and related work associated with Phase 4-2B at the Northeast Arkansas Regional Solid Waste Management District (NEARSWMD) Class 1 Landfill located near Paragould, Arkansas. Figure 1 illustrates the geographic location of the facility.

FIGURE 1. SITE LOCATION MAP

NEARSWMD Class 1 Landfill



The ensuing document summarizes the earthwork, construction of the subgrade, bottom composite liner system, geosynthetics, leachate collection system, and the protective cover system. Correspondence, details, quality control test results, and a certification associated with the construction are also provided. This document, in conjunction with the project as-built drawings, is intended to satisfy the requirements of Arkansas Regulation 22, Section 22.428.

1.1 General

The construction of Phase 4-2B was conducted in accordance with the following documents: “Project Manual – Phase 4-2B for Northeast Arkansas Regional Solid Waste Management

District, Class 1 Landfill Phase 4-2B Construction,” by Terracon Consultants, Inc., dated April 2018.

Permit Modification Drawings dated November 2004 (Doc ID 24890).

“Regulation Number 22, Solid Waste Management Rules,” by Arkansas Department of Pollution Control and Ecology, Solid Waste Management Division dated March 28, 2007.

1.2 Site Description

NEARSWMD owns and operates a Class 1 Solid Waste Landfill (Landfill) located near Paragould in Greene County, Arkansas. The Landfill is located at 1810 Greene Road 890, Paragould, Arkansas. The Landfill has been designed, constructed, and is permitted (Permit 0120-S1-R5) by the Arkansas Department of Environmental Quality (ADEQ) to accept all types of Class 1 wastes as defined in Arkansas Regulation 22. Figure 2 illustrates the location and orientation of Phase 4-2B in relation to the rest of the site.

1.3 Project Description

This project involved the construction of approximately 4.7 acres of composite liner system and leachate collection system. The following information summarizes the construction sequence associated with the construction of Phase 4-2B. Site preparation, excavation to subgrade, and grading of cell area; Preparation of subgrade; Verification and/or Installation and quality assurance testing of a 24-inch thick compacted

clay liner, placed at a minimum of 95% of the Standard Proctor density with a maximum hydraulic conductivity of 1 x 10-7 cm/s;

Installation and quality assurance testing of a 60-mil HDPE textured geomembrane liner; Installation of a leachate collection system consisting of a center collection pipe embedded

in gravel and geotextile; and Installation of a drainage/protective cover layer.



Phase 4-2B has three distinct zones: (1) East Slope Area, (2) Central Corridor and (3) West Slope Area. The east and west slope areas are the zones of Phase 4-2B where the unit is constructed over existing trench method and area-fill pre-Subtitle D waste cells or areas of “piggy-back" construction. The Central Corridor consisted of native clays and silts with no waste previously placed in the area. The CQA Report is organized using tables, figures, and appendices to provide documentation of the observations and material testing of the construction of Phase 4-2B. Appendix A contains the Project Record drawings. Daily project field records are presented in Appendix B. As required by Reg.22.428(i) the CQA Report includes record drawings of Phase 4-2B and the appendices and figures identify the following: Reg.22.428(i)(1) - The limits of liner or final cover barrier construction; FIGURE 2 and the as-built drawing in Appendix A depict the limits of the constructed bottom liner system for Phase 4-2B. Reg.22.428(i)(2) - The top and bottom liner or final cover barrier elevations at 50' intervals referenced to the site grid coordinate system; The as-built drawing in Appendix A provides the top and bottom elevations of the constructed clay liner system at 50' intervals referenced to the site grid coordinate system. Reg.22.428(i)(3)- If a granular drainage blanket is utilized in the design, top of blanket elevation should be identified at 50' elevations; Appendix A provides the bottom elevations of the constructed drainage layer system at 50' intervals referenced to the site grid coordinate system. Depth verification for the drainage layer was performed at 50’ spacing to confirm that at least one foot of drainage blanket depth was placed. Reg.22.428(i)(4) The location and elevation of slope breaks, leachate piping, leachate sumps and trenches, berms, and any other features which are material to the disposal area construction; Appendix A (As-built Record Drawing) provides the location and elevation information and other features of Phase 4-2B construction. Reg.22.428(i)(5) A key map showing the location of the construction in relation to the permitted design, along with an identification of areas previously constructed and areas yet to be constructed; Figure 2 depicts the limits of the constructed bottom liner system for Phase 4-2B in relation to the permitted design, along with an identification of areas previously constructed and areas yet to be constructed.



Reg.22.428(i)(6) Compaction and permeability testing locations; Field logs and Drawings in Appendix E, Appendix F, and Figures 3 through 6 provide compaction and permeability test locations for the bottom liner system of Phase 4-2B. Reg.22.428(i)(7) If necessary to document leachate head level compliance (subsections (a)(2) and (g)(6) of this section), the report should also indicate the lowest point of the liner constructed not including leachate trenches and sumps. Appendix A provides the lowest point of the liner constructed not including leachate trenches and sumps. However, Phase 4-2B ties into the up-gradient end of Phase 4-2A and does not include sump construction. Leachate is conveyed downstream through Phase 4-2A to the sump location along the north end of the landfill phase. Reg.22.428(i)(8) In addition, the certifying professional shall make a statement that the cell was constructed in accordance with the permit drawings and narrative. The report should also include a list of any deviations from the permitted drawings, if they exist, and reasons for the deviations. Phase 4-2B was constructed as close as possible and in accordance with the permit drawings and narrative and the plans and specifications, unless otherwise noted. No deviations from the planned construction were identified that would effect the overall project performance.



1.4 Key Personnel

CEG Construction, Inc. (CEG) was selected as the general contractor to perform the earthwork for the project including excavation to subgrade, reworking and placement of the clay liner in lifts, installation of the leachate collection system, placement of protective cover, and the other improvements at the site. Installation of the textured HDPE liner and the leachate collection trench geosynthetics was subcontracted to Texas Environmental Plastics (TEP). The key personnel for each participating firm in the project are listed below.

Owner: NEARSWMD Jason Wolfenbarger, NEARSWMD Executive Director

CQA Consultant:

Terracon Certifying Engineer: F. Owen Carpenter, P.E., P.G Project Field Engineer: Tony Bardella CQA Monitors: Robert Diaz, Scott McDonald

Survey Control:

Mason Surveying & Consulting Johnny Mason, P.E., R.P.L.S.

Soil Testing Laboratory:

Terracon Cincinnati Laboratory

Geosynthetic Testing Laboratory: TRI / Environmental, Inc. (TRI), Austin, Texas

Soils Contractor: CEG Construction, Inc. Site Superintendent: Bentley Grissom

Geosynthetics Contractor:

Texas Environmental Plastics (TEP) Project Manager: Bob Nantz Project Coordinators: Rone and Somsak



2.0 DEVIATIONS FROM PERMITTED PLANS AND SPECIFICATIONS

The certification reporting requirements of Regulation 22.428(i) anticipate the inclusion of summaries regarding changes from design and material specifications and a list of any deviations from the permitted drawings, and the reasons for deviations. During the construction of Phase 4-2B, no identified deviations from the permitted plans and specifications were encountered.

3.0 SURFACE PREPARATION

On the east and west slopes, a minimum 6-inch thick layer of existing topsoil and vegetation was removed with a dozer and excavator. Depth soundings were excavated on a 50' grid over both of the slopes to confirm that the existing in place clay was greater than 6-inches thick. If suitable, the uppermost 6-inch layer of in-place cover material clay was reworked and qualified as the first 6-inch lift of the newly constructed bottom liner system. Subgrade elevations in the slope areas were assigned an elevation on top of the initial 6-inch lift. A minimum of 18 inches of additional clay liner were then placed over the initial 6-inch lift to form the two-foot thick compacted clay liner. The Central Corridor area was excavated to subgrade elevation. Two feet of compacted clay was then added above the subgrade to constitute the clay component of the composite liner system. Surface preparation activities occurred during June 2018 to July 2018. The elevations associated with the subgrade surface established are provided in Appendix A.

4.0 CLAY LINER SYSTEM INSTALLATION

The following section describes the construction of the bottom clay liner system. The 24-inch thick compacted clay liner corresponding to Phase 4-2B was completed during July and August 2018 using on-site soils.

4.1 Project Specifications

The project construction plans specified the clay liner to be compacted in lifts to at least 95% standard proctor maximum dry density within a range of 0 to 6 percent above optimum moisture. As required in 40 CFR 258 Subpart D and Arkansas Regulation 22, the hydraulic conductivity of

the clay was not to exceed 1 x 10-7 cm/s.

4.2 Construction Procedures

As previously described in Section 3.0, the 24-inch thick compacted clay bottom liner consists of a 6-inch thick in-situ clay layer as well as three six-inch thick compacted clay layers on the slopes and four 6-inch thick lifts on the floor (Central Corridor). The in-situ clay layer was disked, moisture conditioned and compacted to meet the minimum project specifications. Placement of new clay liner material was accomplished using tractors with pans, a tractor with a disc, dozers,



and a sheepsfoot compactor and a smooth drum roller. The clay liner was moisture conditioned during placement to achieve appropriate compaction and acceptable permeability characteristics. Finished grading of the surface was accomplished by utilizing laser-leveling equipment attached to earth moving equipment. The as-built drawing located in Appendix A provide the elevations associated with the top of the clay liner for the bottom liner system.

4.3 Pre-Construction Testing of Clay Liner Material

Field and laboratory testing of the clay liner system was completed as specified in the project specifications, the facility CQA plan, and in accordance with the requirements of Arkansas Regulation No. 22. Before placement of new soils, and during construction, soil samples were obtained from the excavation and clay stockpiles at a minimum frequency of one test per 20,000 cubic yards of soil placed. Appendix C contains the results of the clay liner material pre-construction testing. Table 1 summarizes the results of the pre-construction testing.

TABLE 1

CLAY LINER MATERIALS PRE-CONSTRUCTION TEST SUMMARY

Test Description

Moisture/Density Relationships ASTM D698

Atterberg Limits ASTM D4318

Particle Size Analysis

ASTM D1140, D422

Soils Classification

(USCS)

Remolded Permeability

(cm/sec) D5084

Project

Requirements

Minimum 95% Standard Proctor

maximum dry density

P.I. should be greater

than 10

≥ 30% passing No. 200 sieve

≥ 80% passing No. 4 sieve

SC, CL, or CH

1.0X10-7

or less

Sample Number

Test Results

PC-3

Max Dry Density: 107.4 pcf Opt. Moisture: 14.4%

L.L. 30 P.L. 19 P.I. 11

97.0% passing No. 200 Sieve

100.0% passing No. 4 sieve

CL

9.6X10-8

During pre-construction characterization of the site, samples PC-1 and PC-2 were extracted from the soils that were used for construction of the first 6-inch lift on each of the slopes. The analyses of these samples were used as construction testing results, as the soils were qualified in place and used during construction of the clay lifts. Pre-construction testing (PC-3) revealed that the borrow area soils to be used for construction of the clay liner component had marginal plasticity characteristics, and therefore would require more

Phase 4-2B CQA Certification Report Northeast Arkansas RSWMD ■ Class 1 Landfill (Revised November 2018) ■ Project No. 35177287


closely controlled moisture and density emplacement conditions during field compaction in order to yield acceptable permeability results during performance sampling and testing. Sample PC-3 was compacted to varying moisture and density in lab specimens and tested for permeability. The laboratory permeability results at varying moisture and density allowed the development of an acceptable zone for permeability that was generally moist of optimum and greater than 95%, with the requirement being ≥ 4% wet of optimum at 95% Standard Proctor density. Appropriate emplacement conditions were used in the field to assure the materials would meet the permeability requirement during performance testing.

4.4 Construction Testing of Compacted Clay Liner Material

Approximately 201,988 square feet (14,962 cubic yards) of compacted clay liner were required to tie into existing clay liner from previously constructed cells and establish the soil barrier component of the composite bottom liner system. During the construction of the compacted clay liner, samples were obtained for laboratory testing to verify the consistency of the materials during construction. The results of the construction laboratory testing are included in Appendix D. Table 2 summarizes the results obtained from laboratory testing of the clay liner material. Based upon the results of the construction testing performed, the clay liner borrow material was marginal in relation to project specifications. During construction, more silty materials were recognized in the borrow area soils, and samples were analyzed for properties related to the project specifications. Material testing during construction was used both to identify adequate materials as well as to avoid materials with inadequate plasticity and permeability characteristics in order to achieve acceptable performance testing of the compacted clay liner via permeability testing of undisturbed (thin-wall) field samples.



TABLE 2 CLAY LINER MATERIALS CONSTRUCTION TEST SUMMARY

Test Description

Moisture/Density Relationships ASTM D698

Atterberg Limits ASTM D4318


ASTM D1140, D422


(USCS)

Permeability(cm/sec) D5084

Project

Requirements

Minimum 95% Standard Proctor maximum dry density

P.I. should be greater than 10

≥ 30% passing No. 200 sieve ≥ 80% passing No. 4 sieve

SC, CL, or CH

1.0X10-7

or less

Sample Number

Test Results

PC-1


L.L. 36 P.L. 19 P.I. 17



CL

5.2X10-8

PC-2


L.L. 39 P.L. 19 P.I. 20



CL

2.0X10-8

CL-C1

Max Dry Density: 106.8 pcf

Opt. Moisture: 16.0%

L.L. 24 P.L. 18 P.I. 6



CL-ML

5.3X10-8

CL-C2



L.L. NP P.L. NP P.I. NP


100% passing No. 4 sieve

ML

9.9X10-6

CL-C3



L.L. 30 P.L. 21 P.I. 9



CL

2.2X10-7

CL-C4



L.L. NP P.L. NP P.I. NP



ML

2.1X10-7

CL-C5



L.L. 28 P.L. 19 P.I. 9

91.0% passing No.200 Sieve


CL

4.8X10-8



CL-C6



L.L 28 P.L 19 P.I. 9


99% passing No. 4 Sieve

CL

6.9X10-8

P18

Max Dry Density:

Opt. Moisture:

L.L 32 P.L 20 P.I. 12


100% passing No. 4 Sieve

CL

4.3X10-8

Field moisture and density tests were performed at a minimum rate of one test for every 10,000 square feet per compacted lift of emplaced clay liner. Figure 3 through Figure 6 illustrate the locations of the field moisture and density tests for each compacted lift of clay liner. Appendix E includes the field logs for the moisture and density testing performed in association with the Cell 4-2B construction. Based upon the results of the moisture and density tests performed by Terracon, the 24-inch thick compacted clay liner complies with the project specifications. Thin-walled, Shelby tube samples were obtained from each lift at a minimum rate of one test for every 40,000 square feet per lift. Figure 3 through Figure 6 illustrate the locations where the Shelby Tube samples were obtained for each compacted lift of clay. The tubes were sealed and delivered to the laboratory for performance testing of permeability using a flexible-wall permeameter (ASTM D-5084). As indicated in TABLE 3, permeability results for the completed

compacted clay liner met the project requirements (less than or equal to 1x10-7 cm/s). Appendix F contains the compacted clay liner performance testing results.



TABLE 3 PERMEABILITY RESULTS SUMMARY

Test No.

Lift No.

Test Results

Test No.

Lift No.

Test Results

Average Permeability

(cm/sec)

Pass/Fail Average Permeability

(cm/sec)

Pass/Fail

P-1 1 2.8X10-8 Pass P-13 2 1.9X10-8 Pass

P-2 1 3.0X10-8 Pass P-14 3 1.9X10-8 Pass

P-3 1 2.3X10-8 Pass P-15 3 2.1X10-8 Pass

P-4 1 2.3X10-8 Pass P-16 3 2.1X10-8 Pass

P-5 1 4.2X10-8 Pass P-17 3 3.9X10-8 Pass

P-6 1 2.0X10-8 Pass P-18 3 4.3X10-8 Pass

P-7 1 1.8X10-7 Fail P-19 3 2.1X10-8 Pass

P-7R 1 2.1X10-8 Pass P-20 4 1.9X10-8 Pass

P-8 2 2.1X10-8 Pass P-21 4 2.3X10-8 Pass

P-9 2 2.1X10-8 Pass P-22 4 1.9X10-8 Pass

P-10 2 3.8X10-8 Pass P-23 4 1.1X10-8 Pass

P-11 2 6.5X10-8 Pass P-24 4 1.9X10-8 Pass

P-12 2 2.0X10-8 Pass P-25 4 3.2X10-8 Pass

5.0 GEOSYNTHETIC LINER INSTALLATION

Installation of the geosynthetic components for the bottom liner system of Phase 4-2B occurred during August 2018. Approximately 205,633 square feet of 60-mil textured HDPE geomembrane liner was installed during construction of Phase 4-2B.

5.1 Manufacturer’s Quality Control Certificates

Manufacturer’s Quality Control Certificates (roll certification reports) were submitted for comparison of the delivered material properties with the project specifications. Copies of the manufacturer’s certificates for the geomembrane are provided in Appendix H and the manufacturer’s certificate for the geotextile is provided in Appendix R. An inventory of the geomembrane used at the site is included in Appendix J. Based upon the manufacturer’s quality control certificates, the supplied materials comply with the project specifications.



5.2 Material Conformance Testing

Conformance test samples of the geosynthetic materials were tested by TRI Environmental, Inc. (TRI) for compliance with the project specifications. Copies of the laboratory conformance test results on the geomembrane are included in Appendix I and a copy of the laboratory conformance test results on the geotextile is included in Appendix R. Based upon the results of the conformance testing by TRI, the geosynthetic materials supplied comply with the project specifications.

5.3 Deployment of Geosynthetics

Prior to the deployment of the geomembrane, the geosynthetic installation manager and the CQA field representative accepted the subgrade. A Copy of the subgrade acceptance forms is included in Appendix L. Deployment of the panels was accomplished by use of a Track-hoe, Sky Track, and manual labor to transport each panel into place. A Terracon field representative monitored the deployment of panels. The daily deployment logs for the geosynthetics can be found in Appendix M. Panel layouts of the bottom liner system for Phase 4-2B are illustrated on Figure 7. Terracon field representatives reviewed each panel and noted any manufacturing and deployment defects for repair. The panels were anchored temporarily with sandbags to prevent wind damage. The panels were permanently anchored at the top of the slopes by either welding to existing liner or by placing inside anchor trenches filled with compacted clay. Vents and flaps for passage of underlying landfill gas were installed in the geomembrane as required by the project drawings and specifications.

5.4 Geomembrane Trial Seam Monitoring

Before startup of each seaming period (in the morning and after lunch), the fusion and extrusion welder operators were required to prepare a trial seam for the welding machines that were to be used. The seams were tested in the field on a calibrated, gauged tensiometer to check for machine failures or operator errors. Appendix K contains calibration certificates for the geosynthetic field tensiometer. If the tests passed (in peel and in shear), the operator was then allowed to begin seaming. Trial seam logs are presented in Appendix N. The seams were checked for peel and shear. The coupons were required to exhibit a film tear bond (FTB) and to meet the project specifications for peel and shear strength in order to be acceptable.

5.5 Geomembrane Seam Monitoring

The primary seaming method used for joining geomembrane panels was through an automated double track fusion welder. Extrusion welding was used for patches, repairs, intersections of fusion seams, and seam reconstruction. Monitoring of the seaming methods consisted of periodic



visual observation of the seaming process, visual examination of the completed seam, and verification that the seam was welded for its entire length. Seaming imperfections were marked and subsequently repaired in accordance with the project CQA plan. The panel layout of the geomembrane installation showing seam locations for the bottom liner system are presented on Figure 7.

5.6 Non-Destructive Seam Testing and Repair Monitoring

Continuity of seams, seam repairs, and patches were non-destructively tested by the installer using an air pressure test for fusion welds or vacuum box techniques for extrusion welds. Terracon field CQA personnel monitored and documented field testing of the seams to ensure that the tests were performed in accordance with the project CQA plan. Summaries of the geomembrane continuity testing are presented in Appendix O. The location, size, and testing results of seam repairs and patches were documented. Copies of this documentation can be found in Appendix Q.

5.7 Destructive Seam Strength Testing

Each destructive sample was divided into three sections: a sample for field testing, a sample for laboratory testing, and an archive sample. Prior to sending the samples to the testing laboratory (TRI), the samples were tested in the field for peel and shear using a gauged tensiometer. Summaries for the field destructive sampling and laboratory testing for peel and shear are located in Appendix P. Destructive samples were obtained at a minimum frequency of one sample per 500 linear feet of production seam length. The destructive test locations are noted on Figure 7. Based on the results of the seam peel and shear testing performed by TRI and Terracon, each seam complies with the project specifications.

6.0 LEACHATE COLLECTION SYSTEM AND PROTECTIVE COVER

The leachate collection system consists of protective cover overlying the HDPE liner with a minimum of a 2-percent slope (variable) to a leachate collection trench.

6.1 Leachate Collection Pipe

A leachate collection pipe was installed in the center of the Phase 4-2B bottom liner system. The collection pipes consist of a six-inch diameter perforated HDPE pipe wrapped in a gravel protective/drainage bed. The gravel consists of washed gravel with a gradation varying from basically No. 4 to 1 inch in diameter. Table 4 presents the results of laboratory testing of the gravel. The gravel was wrapped with a 10-ounce per square yard non-woven geotextile to protect the system from clogging. The collection pipe gravity drains north to connect to the existing collection pipe at the south end of Phase 4-2A. Appendix R presents the laboratory test results on the gravel used in the drainage system.



6.2 Protective Cover Soil

A 12-inch (min) thick sand protective cover layer was placed on top of the geotextile “burrito” and over the HDPE liner on the bottom of Phase 4-2B, within the Central Corridor. General fill protective cover material was placed on the geomembrane material on the side slopes of Phase 4-2B (up-slope from the Central Corridor area). Appendix R presents the laboratory test results on the sand protective cover layer. Table 4 presents the results of laboratory testing of the sand protective cover. The layer was placed using a low ground pressure dozer while maintaining a 12-inch thick minimum working surface to ensure protection of the underlying geosynthetic liner.



TABLE 4 PROTECTIVE COVER SAND AND LEACHATE COLLECTION GRAVEL

TEST SUMMARY

SAND

Test Description Calcium Carbonate

(%)


ASTM D1140, D422


(USCS)

Permeability(cm/sec)

Project Requirements

NA NA SP ≥ 1.0X10-3

Sample Number Test Results

PC-P1 (Pre-Construction)

NA


SP

5.89X10-2

PC-P2 (Pre-Construction)

NA


SP

3.59X10-2

PC-C1 (Construction)

NA 6% passing No. 200 sieve

SP 3.44X10-2

PC-C2 (Construction)

NA 3% passing No. 200 sieve

SP 4.50X10-2

GRAVEL

Test Description

Particle Size Analysis ASTM D1140, D422


(USCS)

Permeability (cm/sec)

Project Requirements

NA GP ≥ 1.0X10-3

Sample Number Test Results

G-P1 (Pre-Construction)


GP 2.01 X10+1

G-C1 (Construction)


GP 1.81 X10+1



7.0 INTERFACE FRICTION TESTING

Section #3 - 2.6 of the approved CQA Plan states that prior to approving the cell for disposal, the proposed materials shall be tested prior to use on site. Previous test results from the Phase 4-2A construction were utilized due to the consistency in soils at the site and the use of the same geomembrane as the previous cell. According to the laboratory results, the materials that were proposed for construction were acceptable. A summary of the interface friction testing results are provided in Table 5 below. A copy of the laboratory results are presented in Appendix S.

TABLE 5 INTERFACE FRICTION TEST SUMMARY

Interface Testing Criteria Specification Results

1. Geomembrane/Drainage Layer Interface

Minimum Friction Angle Minimum Interface Adhesion, saturated condition Normal Stress = 0 to 20 psi

25 degrees 0 psf

0 – 20 psi

30.5 degrees 151

5 – 20 psi

2. Geomembrane/Clay Liner Interface

Minimum Friction Angle Minimum Interface Adhesion, unsaturated condition Normal Stress = 0 to 20 psi

29 degrees 100 psf

0 – 20 psi

43.0 281

5 – 20 psi



7.0 INTERFACE FRICTION TESTING

Section #3 - 2.6 of the approved CQA Plan states that prior to approving the cell for disposal, the proposed materials shall be tested prior to use on site. Previous test results from the Phase 4-2A construction were utilized due to the consistency in soils at the site and the use of the same geomembrane as the previous cell. According to the laboratory results, the materials that were proposed for construction were acceptable. A summary of the interface friction testing results is provided in Table 5 below. A copy of the laboratory results is presented in Appendix S.

TABLE 5 INTERFACE FRICTION TEST SUMMARY

Interface Testing Criteria Specification Results

1. Geomembrane/Drainage Layer Interface

Minimum Friction Angle Minimum Interface Adhesion, saturated condition Normal Stress = 0 to 20 psi

25 degrees 0 psf

0 – 20 psi

30.5 degrees 151

5 – 20 psi

2. Geomembrane/Clay Liner Interface

Minimum Friction Angle Minimum Interface Adhesion, unsaturated condition Normal Stress = 0 to 20 psi

29 degrees 100 psf

0 – 20 psi

43.0 281

5 – 20 psi

8.0 CONSTRUCTION PROBLEMS AND SOLUTIONS

Construction of the compacted low permeability soil liner began in July 2018 with the objective of constructing a compacted clay liner that would exhibit an in-place hydraulic conductivity of ≤

1.0X10-7 cm/sec and would be structurally stable. Pre-construction testing of borrow area soils took place in late June. NEARSWMD personnel designated an area within their operational borrow area for the excavation of soils for bottom liner construction. Darker brown clayey soils in the designated area were sampled for pre-construction testing. As discussed in Sections 4.3 and 4.4 above, pre-construction testing and evaluation of the borrow area revealed that the target soils were marginal in plasticity characteristics and would therefore have to be emplaced with acceptable moisture and density conditions. Construction utilizing borrow area soils began in mid-July, and soils similar to the PC-3 pre-construction sample were excavated and compacted using carefully controlled emplacement conditions of moisture content and density. An acceptable zone of emplacement conditions was generated and updated during construction to confirm that the objective would likely be met.



Within approximately 10 days, and roughly at the beginning of lift three of the soil barrier system, borrow area excavation encountered lighter colored soils with silty appearing texture. These soils were visually avoided by the contractor. Samples were taken to confirm the identified soils’ properties as they were encountered, and it was confirmed that the lighter colored soils with silty texture were not acceptable and therefore were not used in the clay liner. Darker brown and gray clayey soils were used throughout construction of the clay liner. The utilized soils met the hydraulic conductivity criterion because the construction practices use to install the liner were appropriate and carefully controlled.

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