Summary

United States

Environmental Protection

Agency

Quality Assurance and Quality

Control for Waste Containment

Facilities

National Risk Management

Research Laboratory

Cincinnati, OH 45268

Research and Development

It is generally agreed that both quality assurance (QA) and quality control

(QC) are essential to the proper installation and eventual performance of environmentally safe and secure waste

containment systems. Even further,

there are both manufacturing and construction aspects to many of the natural and synthetic materials that are

involved. At issue, however, is the appropriate level of QA and QC, the

specific measures to be taken, the particular test methods to be used, the

frequency of these test methods and

the interrelationships of the various

personnel that may be involved. This

technical guidance document (TGD), or

“manual”, has been prepared in an effort to address these issues.

The manual is not design oriented. It

presumes that a separate set of plans

and specifications has been, or will be,

prepared for the specific site in question. Instead, the manual is focused on

the preparation and necessary ingredients of a QA plan (synonymously called

a QA document). This EPA technical

guidance document presents information that can be used to craft a sitespecific plan for QA (and QC) purposes.

The opening chapter is focused on

the organizational concepts of a typical project and presents an overview

of QA/QC activities. It is an updated

and greatly expanded version of an earlier EPA technical guidance document

on the same topic, i.e., EPA/530-SW86-031. Following the opening chapter

they are separate chapters on the specific components of waste containment

systems. In the order of their presentation they are as follows:

• compacted soil liners

• geomembranes

• geosynthetic clay liners

• soil drainage systems

• geosynthetic drainage systems

• vertical cutoff walls

• ancillary materials, appurtenances

 and other details

This Summary was developed by

EPA's National Risk Management Research Laboratory, Cincinnati, OH, to

communicate the salient points of the

state of the practice for construction

quality at waste containment facilities

that are fully documented in a separate

report of the same title (see Report

ordering information at back).

Chapter 1 - Concepts and

Overview

Upon defining the interrelated terms of

manufacturing quality control (MQC),

manufacturing quality assurance (MQA),

construction quality control (CQC) and construction quality assurance (CQA), a flow

chart describing the organizational structure of a typical project is presented, see

Figure 1. Within this flow chart and its

description are a number of contentious

issues. For example, the corporate association between owner/operator, design

engineer and QA organization must be

kept separate so that a constant set of

checks and balances can result. If such

separateness is challenged the interrelations between organizations can be requested by the permitting agency. Also,

the geosynthetics manufacturer/fabricator

must have at least 10,000,000 ft2 (250

acres) of experience. This may be difficult

for new suppliers/installers, but the requirement is considered to be necessary.

Lastly, both CQC and CQA organizations

must have a minimum number and experience level of “certified” personnel on

projects by Jan 1, 1996. The following

EPA/600/SR-93/182 September 1995

David E. Daniel and Robert M. Koerner
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Figure 1. Organizational structure of QA/QC inspection activities.

schedules are recommended (Tables 1

and 2). A certification program is ongoing

and is available through the National Institute for Certification in Engineering Technologies (NICET), at 1420 King Street,

Alexandria, VA 22314.

Interspersed throughout the opening

chapter is the critical nature of the QA plan.

The chapter clarifies and elaborates upon

all issues and details that are not included

in the project-specific plans and specifications. As with the project plans and specifications, the QA plan is always site

specific. The QA plan must be submitted

to, and approved by, the regulatory agency

before a construction permit is issued. The

QA plan should also be available for all

construction organizations (i.e., general

contractor, earthwork contractor, geosynthetic manufacturer and geosynthetic installer) to review before the project is bid.

This is necessary so that the level of proposed QA effort is clearly known and anticipated by all parties involved with

manufacturing, construction and installation of the various materials.

Chapter 2 - Compacted Soil

Liners

Compacted soil liners consist of natural

clay materials or amended soil liners (usually with bentonite) to achieve the regulatory required value of the hydraulic

conductivity. Generally the value must be

equivalent to, or lower than, 1 X 10–7 cm/

sec. The chapter provides detailed information concerning critical variables, field

measurements, inspection of borrow services and their excavation, preprocessing

of materials, placement of loose lifts, remolding and compaction, protection of the

compacted soil, test pads and final approval. The critical relationship between

clay soil moisture content and density are

explained thoroughly as illustrated in Figures 2 and 3. Soils must be compacted at

the proper water content to achieve the

desired low hydraulic conductivity. For the

soil illustrated in Figures 2 and 3, the

optimum water content is 17%. The soil

shown in Figure 2 was compacted with

standard Proctor energy at a water content of 16%, which left large voids between clods of clay and which produced

an unsatisfactorily large hydraulic conductivity. When the soil was wetted up to a

water content of 20%, the chunks of clay

were softened sufficiently to enable good

remolding during compaction; hydraulic

conductivity was adequately low. Specific

guidance on test methods, procedures,

sampling frequency, accept/reject considerations and field experiences are described throughout the chapter.
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both a filter and a separator. Geotextiles

are described in this chapter with respect

to their resin types, formulations and manufacturing. Protection (via wrapping), handling, storage, placement, seaming and

backfilling/ covering are all described.

Seam types and tests, along with the relevant geotextile tests are described.

Chapter 7 - Vertical Cutoff Walls

While most of the topics discussed in

this manual have the barrier material in a

horizontal or gently sloped orientation,

there is also a pressing need at some

sites for vertical barriers. Many sites (both

abandoned and newly constructed) require

vertical cutoffs which are either extended

into a low hydraulic conductivity layer beneath it (an aquiclude), or are deep enough

to thwart underlying seepage. These cutoff walls are generally constructed using

the slurry wall method and are then backfilled with a low permeability material, e.g.,

soil/bentonite. Figure 5 shows the concept.

The chapter progresses through an introduction, the concept of vertical cutoff

walls, construction issues, various types

of cutoff walls, specific CQA requirements

and post construction tests to assure continuity of the completed wall against seepage losses. The inclusion of a

geomembrane within the final backfill soil/

material is also described insofar as the

various types available and the methods

for joining the individual panels together.

Chapter 8 - Ancillary Materials,

Appurtenances and Other

Details

Clearly, waste containment systems are

a juxtaposition of an array of elements, all

of which are necessary to have an environmentally safe and secure waste containment system. Thus, the concluding

chapter of the manual describes the “other”

details and materials necessary to achieve

the final goal of a complete waste containment system.

Included in the chapter are plastic pipe

(aka “geopipe”) which is used for leachate

collection and removal systems, leak detection systems and peripheral drainage

around the perimeter of the site for surface water removal being shed from cover

systems. The pipes are made from either

HDPE or PVD and both smooth wall and

corrugated plastic pipe systems are in use.

The types of pipe, handling and conformance testing are included in this subsection.

Sumps, manholes and risers to remove

leachate and to assess leak detection are

also included. Various strategies used by

designers are noted with appropriate comConstruction guidelines are included whenever appropriate since much of the routine testing in installation of compacted

soil liners is provided by the CQA personnel who must interact with the CQC personnel on a continuous basis.

Chapter 3 - Geomembranes

Geomembranes, also called flexible

membrane liners (FMLs) in many state

regulations, are factory manufactured synthetic liner materials made from various

polymers. As such, there are both manufacturing and construction aspects to be

considered. This chapter addresses the

types and manufacturing of the most commonly used geomembranes. They are

listed in Table 3 along with their appropriate formulations. Elements of manufacturing are described so as to develop

adequate MQC/MQA protocol for

geomembranes made from extrusion processes as well as calendered types.

The chapter also focuses on the construction aspects of geomembranes, i.e.,

CQA and CQC, insofar as proper seaming and joining is concerned. Emphasis is

placed on the various field seaming methods as noted in Table 4. All types are

described in a complete manner.

A complete description of seam tests

(shear and peel) is presented with appropriate guidelines on sampling strategies

and generally accepted minimum values.

The various nondestructive test (NDT)

methods given in Table 5 are addressed

with detailed descriptions of each method.

Handling, storage, backfilling and covering of geomembranes are also addressed. Included in the chapter are the

commonly referenced test methods, insight into the recommended test frequencies and the necessary information with

which to formulate a QA plan.

Chapter 4 - Geosynthetic Clay

Liners

The newest of liner, or barrier, materials are called geosynthetic clay liners

(GCL’s). These materials are composed

of geosynthetics (either geotextiles or

geomembranes) with an encapsulated or

associated layer of bentonite. While the

layer of bentonite is much thinner than a

compacted soil liner, the hydraulic conductivity of bentonite is the lowest of any

naturally occurring soil material, e.g., it

typically varies from 1 X 10–9 to 5 X 10–9

cm/sec. Cross sections of the various commercially available types of GCL’s are illustrated in Figure 4.

The chapter describes the type and

composition of GCLs followed by salient

features of the manufacturing process.

Bentonite tests and their recommended

frequencies are suggested. Sufficient detail as to the associated geotextiles or

geomembranes are presented. This is followed by sections on handling, installation, and backfilling/covering. Included are

recommended test methods for manufacturing and construction and the recommended frequency of testing for the

formation of an appropriate QA plan.

Chapter 5 - Soil Drainage

Layers

Both sands and gravels are utilized in

waste containment facilities for leachate

collection layers beneath the waste, leak

detection layers between two liners beneath the waste, and for surface water

drainage layers above the waste in the

final cover. Thus it is necessary to include

them as an essential part of a waste containment liner system.

The chapter presents an introduction,

the relevant soil types, control of materials, location of borrow sources, processing of materials, placement, compaction

and protection of granular drainage soils

and filters. Both sands and gravels are

considered. Test methods and frequencies are presented, e.g., see Table 6.

Concerns are also addressed. The use of

limestone sources is critiqued and some

identification materials and controls are

offered.

Chapter 6 - Geosynthetic

Drainage Systems

So as to counterpoint the natural soil

drainage and filter layers just described,

this chapter presents geosynthetic drainage and filter materials. The decision to

use natural soil materials or geosynthetics

is a design decision and is not addressed

in this manual.

Geonets are generally made from high

density polyethylene (HDPE) and the typical formulation along with the variations in

manufacturing are presented. Handling,

storage, acceptance/conformance testing,

placement, joining, and backfilling are addressed in a sequential manner.

Other types of drainage cores made

from columns, prisms, cuspations (single

or double), meshes and mats are also

described. As with other chapters, the requisite test methods, their suggested frequencies and construction details are

presented.

Insofar as geosynthetic drainage materials are concerned (i.e., they all provide

for in-plane flow of leachate or water)

geonets and geocomposite drainage cores

have open spaces to allow the liquid to

flow within them. Necessarily, they have a

geotextile covering attached to their exposed surface(s). The geotextile acts as
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mentary. Necessary in this regard are penetrations of various barrier layers. Different types of compacted clay liner,

geomembrane, and geosynthetic clay liner

penetrations are presented, although the

final decision and its appropriate design is

obviously at the discretion of the design

engineer.

Anchor trenches are illustrated with pros

and cons of the various configurations.

Access ramps are critically important

for below-grade waste containment facilities. Numerous problems have arisen by

improper design and/or construction practices. Selected comments and precautions

are given.

Geosynthetic reinforcement materials

are seeing an increased use in waste

containment facilities. Veneer reinforcement of leachate collection systems and

cover soils represents a major need for

the use of geogrids or high strength

geotextiles. The growing tendency of vertical and lateral expansions of existing

landfill facilities for additional waste placement also uses geogrids and high strength

geotextiles. Both of these applications are

illustrated in Figure 6 and are described in

this subsection.

The exposed surface of the landfills and

waste piles must necessarily be resistant

to water and wind erosion. Thus a subsection on the use of geosynthetic erosion control systems is included.

Lastly, the use of geomembranes as

floating covers for surface impoundments

is included in the manual. Details of their

installation and inspection are included.

In conclusion, this technical guidance

document (or “manual”) addresses QC and

QA for all facets of the individual components of a waste containment system for

landfills, surface impoundments and waste

piles. Not only are the liner and cover

systems addressed, but vertical barriers

as well. Note that the QA plan is not

written in a “cook book” fashion since the

final QA plan is clearly site specific and

material specific. However, the essential

items for a successful QA plan are presented and with judicious use of the

manual, coupled with the experience of

the designer and CQA organization, a

proper QA plan can be written.

Accompanying this technical guidance

document are numerous references, most

of which are EPA manuals or ASTM test

methods. The EPA manuals are available

either from the Agency or NTIS. To assist

the reader in gathering the various test

methods, a companion document published by the American Society of Testing

and Materials (ASTM) is available which

reprints all of the test methods referenced

in the manual. Included are 79 separate

ASTM test methods and 10 additional referenced test methods by other standardization group.

Footnotes:

1. This EPA manual is available

from NTIS at a cost of $44.50

each. The NTIS Number is

PB94-159100.

2. The companion document of 89

test methods referenced in the

manual is available from ASTM

for $77.00. The ASTM member

price is $69.00. The ASTM Pub

lication Code Number (PCN) is

03-435193-38.

3. An expanded and somewhat

modified version of the manual is

available from ASCE Sales De

partment at the list price of $48.00

and the ASCE member price of

$36.00.

Table 1. Recommended Implementation Program for Construction Quality Control (CQC) of

Geosynthetics* (Beginning Jan 1, 1993)

No. of Field Crews** End of 18 Mo End of 36 Mo

At Each Site (i.e., June 30, 1994) (i.e, Jan 1, 1996)

1-4 1 - Level II 1 - Level III***

≥ 5 1 - Level II 1 - Level III***

2 - Level I 1 - Level I

Table 2. Recommended Implementation Program for Construction Quality Control (CQA) of

Geosynthetics* (Beginning Jan 1, 1993)

No. of Field Crews** End of 18 Mo End of 36 Mo

At Each Site (i.e., June 30, 1994) (i.e, Jan 1, 1996)

1-2 1 - Level II 1 - Level III***

3-4 1 - Level II

1 - Level I 1 - Level III***

1- Level I

≥5 1 - Level II

2 - Level I 1 - Level III***

1 - Level II

1 - Level I

* Certification for natural materials is under development as of this writing.

** Performing a Critical Operation; Typically 4 to 6 People/Crew.

*** Or PE with applicable experience.

Table 3. Types of Commonly Used Geomembranes and Their Approximate Weight Percentage Formulations*

Geomembrane Carbon Black

Type Resin Plasticizer Filter or Pigment Additives

HDPE 95-98 0 0 2-3 0.25-1.0

VLDPE 94-96 0 0 2-3 1-4

Other Extruded Types 95-98 0 0 2-3 1-2

PVC 50-70 25-35 0-10 2-5 2-5

CSPE-R 40-60 0 40-50 5-40 5-15

Other Calendered Types 40-97 0-30 0-50 2-30 0-7
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Figure 2. Photograph of highly plastic clay compacted with standard proctor effort at a water content of 16% (1% dry of optimum).
6

Figure 3. Photograph of highly plastic clay compacted with standard proctor effort at a water content of 20% (3% wet of optimum).
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Table 4. Possible Field Seaming Methods for Various Geomembranes Listed in this Manual

 Type of Geomembrane

Type of Seaming

Method HDPE VLDPE Other PE PVC CSPE-R Other Flexible

extrusion

(fillet and flat) A A A n/a n/a A

thermal fusion

(hot wedge and hot air) AAAAAA

chemical

(chemical and bodied

chemical)n/a n/a n/a A A A

adhesive

(chemical and contact) n/a n/a n/a A A A

Note: A = applicable; n/a = not applicable

Table 5. Applicability of Various Nondestructive Test Methods to Different Seam Types and Geomembrane Types

NDT Method Seam Types* Geomembrane Types

1. air lance C, BC, Chem A, Cont. A all except HDPE

2. mechanical point stress all all

3. dual seam HW, HA all

4. vacuum chamber all all

5. electric wire all all

6. electric current all all

7. ultrasonic pulse echo HW, HA

C, BC,

Chem. A, Cont. A HDPE, VLDPE, PVC

8. ultrasonic impedance HW, HA

C, BC,

Chem. A, Cont. A HDPE, VLDPE, PVC

9. ultrasonic shadow E Fil., E Flt., HW, HA HDPE, VLDPE

* E Fil. = extrusion fillet

E Flt. = extrusion flat

HW = hot wedge

HA = hot air

C = chemical

BC = bodied chemical

Chem. A = chemical adhesive

Cont. A = contact adhesive
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Figure 4. Cross section sketches of currently available geosynthetic clay liners (GCLs).
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Table 6. Recommended Tests and Testing Frequencies for Soil Drainage Materials

Location of Sample Type of Test Minimum Frequency

Potential Borrow Source Grain Size (ASTM D-422) 2500 yd3

Hydraulic Conductivity (ASTM D-2434) 2500 yd3

Carbonate Content* (ASTM D-4373) 2500 yd3

Onsite; After Placement Grain Size (ASTM D-422) 1 per Hectare for Drainage

and Compaction Layers; 1 per 650 yd3 for Other Uses

Hydraulic Conductivity (ASTM D-2434) 1 per Hectare for Drainage

Layers; 1 per 650 yd3 for Other Uses

Carbonate Content* (ASTM D-4373) 1 per 2500 yd3

* The frequency of carbonate content testing should be greatly reduced to 1 per 25,000 yd3 for those drainage materials that obviously do not and

cannot contain significant carbonates (e.g., crushed basalt).

Figure 5. Diagram of construction process for soil-bentonite-backfilled slurry trench cutoff wall.
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Figure 6. Geogrid or geotextile reinforcement of (a) cover soil above waste, (b) leachate collection layer beneath waste, and (c) liner system placed

above existing waste (“Piggybacking”).
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David E. Daniel is with the University of Texas at Austin, Department of Civil

Engineering, Austin, TX 78712.

 Robert M. Koerner is with Drexel University's Geosynthetic Research Institute,

Philadelphia, PA 19104.

David Carson is the EPA Project Officer (see below).

The complete report, entitled "Quality Assurance and Quality Control for Waste

Containment Facilities," (EPA/600/R-93/182); (Order No. PB94-159

100AS; Cost: $44.50, subject to change) is available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

National Risk Management Research Laboratory

U.S. Environmental Protection Agency

Cincinnati, OH 45268

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