July
THE USE OF ALTERNATIVE MATERIALS
FOR - .
DAILY COVER AT MUNICIPAL SOLID WASTE LANDFILLS
by
Frederick G. Bohland and Johannes T. Graven
Department of Civil Engineering
University of Pittsburgh
Pittsburgh, PA 15261
EPA Contract No. 68-C1-0018
Eastern Research Group, Xnc.
Project Officer
Robert E. Landreth
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 452S8
RISK REDUCTION SHGXKEERING LABORATORT
OFFICE OF RSSSARCH AND DEVELOPMEST
U.S. ENVXRO1BSEOTAL PROTECTION AGEKCY
CIKCXHH3LT2, OHIO 45258
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
RECIPIENT'S ACCESSION NO.
5. REPORT DATE
The Use of Alternative Materials for Daily Cover
at Municipal Solid Waste Landfills
6. PERFORMING ORGANIZATION CODE
Frederick G. Pohland and Johannes T. Graven
8. PERFORMING ORGANIZATION REPORT NO.
IG ORGANIZATION NAME AND ADDRESS
University of Pittsburgh
Department of Civil Engineering
•Pittsburgh, PA 15261
10. PROGRAM ELEMENT NO.
1. CONTRACT/GRANT NO.
68-C1-0018
12. SPONSORING AGENCY NAME AND ADDRESS
Risk Reduction Engineering Laboratory-Cincinnati, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
Complete
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Robert E. Landreth
(513) 569-7871
The current (ca. 1992) applicability of alternative materials as daily cover at
landfills was assessed from an operational, performance, environmental, and economic
perspective. The types of products and materials considered included commercially
available foams, spray-ons and geosynthetics, as well as indigenous materials, such as
ash-based materials, green waste, sludge, compost and shredded tires. Information on
characteristics, material and equipment requirements, methods of preparation and.
application, climatic and operational considerations, effectiveness, and costs were
obtained from manufacturers/users of alternative daily cover materials (ADCMs) and from
available reports. >
Results of this investigation indicated that use of alternative materials for daily
cover in lieu of soil can augment landfill operations and performance, while enhancing
environmental control. Although applicability varied depending on site specificity and
the particular alternative material used, most materials were easily applied, satisfied
operational and regulatory requirements, saved landfill capacity, decreased requirements
for soil, and facilitated leachate and gas management and control. Whereas most
materials met established criteria for daily cover, their application and evaluation
would be enhanced with the development of consensus performance standards for evaluation,
Further development and integration into overall landfill management practices is also
warranted.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Sanitary landfills
Cover (daily)
Leachate
Fire
Foams
Geosynthetics
Cover materials
Indigenous materials
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (Tins Report)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (Rav. 4-77)
PREVIOUS EDITION IS OBSOLETE
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DISCLAIMER
The information in this document has been funded vholly or in part by the
United States Environmental Protection Agency under Contract Ho. 68-C1-0018; Task
12. It b-as been subjected to the Agency's peer and administrative review, and
it has been approved for publication as an EPA document. Hention of trade names
or commercial products does not constitute endorsement or recoss&endation for vise.
ii
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FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation of
solid and hazardous wastes. These materials, if improperly dealt with, can
threaten both public health and the environment. Abandoned waste sites and
accidental releases of toxic and hazardous substances to the environment -also
have important environmental and public health implications. Ths Risk Reduction
Engineering Laboratory assists in providing an authoritative and defensible
engineering basis for assessing and solving these problems. Its products Bijpt>oxt
the policies, programs and regulations of the Environmental Protection Agency,
the permitting and other responsibilities of State and local governments;, and the
needs of both large and small businesses in handling their wastes responsibly and
economically.
This report is a Technical Resource Document, assessing the applicability
of currently (ca. 1992} available materials as daily cover, in lieu of soil, at
municipal solid waste landfills. Application, climatic, operational, and
economic considerations associated with the use of various alternative materials
areas warranting further consideration and development. This information, is
intended to be useful in evaluating the feasibility and suitability of
alternative cover materials, during landfill design, operation and managesȣB.t,
and in developing appropriate regulations. ,
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
iii
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ABSTRACT
The current (ca. 1992) applicability of alternative materials as daily
cover at landfills was assessed from an operational, performance,
and economic perspective. The types of products and materials considered
included caesaercially available foams, spray-ons and geosynthetics, as veUL as
indigenous materials, such as ash-oased' materials, green, waste, sludge, , .•ebsggost
and shredded tires. Information on characteristics, material and equipment
requirements, methods of preparation, anti application,, climatic and operational
considerations , effectiveness, and costs were obtained from ntanufactrarers/susers
of alternative daily cover materials {ADCMsJ and from available reports,
Results of this investigation indicated that use of alternative saafcerials
for daily cover in lieu of soil can augment landfill operations and perfosBsjaee,
wliile enhancing environmental control. Although applicability varied
an. si.te specificity and the particular alternative material used, most: EtaterjLals
were easily applied, satisfied operational and regulatory requirements,, saved
landfill capacity, decreased re^airs®ents for soil, astd xaciliiated leachsfce and
gas saanagement and control. Whereas csosst; aaaterials met established criteria, for
daily cover, their application and evaluation would be enhanced witfe .the
development of consensus performance standards for evaluation, Itelfcher
development and integration into overall landfill management practices is also
warranted.
This report was submitted in fulfillment of EPS Contract No. 6S-C1-O01B by
the Eastern Research Group tinder sponsorship of the U.S. Environmental Protection
Agency. This report includes assessments from Novesaber 1991 to February 199-3,
and was completed for review as of Hay 1993.
iv
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SUMMARY
The use of alternative materials in lieu of soil for daily cover by
landfill owners and operators has increased significantly in recent years as the
availability of landfill capacity, associated siting challenges and increasing
operational costs prompt changes in landfill management and operations in
attempts to optimize the use of available space- and make landfilling more
effective and efficient. ' Alternative daily cover .materials (ar>C3£s) offer
opportunities for conserving landfill space and.soil resources, while also
meeting health, environmental, aesthetic, and other .site management and use
requirements.
This investigation was conducted to assess the applicability.of currently
available (ca. 1992} alternative materials for use as daily cover at landfills.
The types of products and materials considered included f oasis, spray-ons .and
geosynthetics, as well as various indigenous materials, such as green waste,
sludge, compost and shredded tires. Information on characteristics, material aiad
equipment requirements, methods of preparation and application, climatic and
operational considerations, effectiveness, and costs -were obtained* from
manufacturers and/or users of alternative cover materials. Based oh this
information and its evaluation, operational, performance-related, and economic
features 'and considerations for the use of various alternative cover materials
are presented.
Evaluation of the information obtained during the conduct of this
investigation indicates that: .
Use of ADCMs in lieu of soil can augment operation and performance of
municipal solid waste landfills in terms of ease, of application,
improved effectiveness in meeting site operational and. regulatojry
requirements, savings in landfill capacity, decreased .requirements for
soil, and facilitated leachate and gas management, and control,
- Most alternative daily cover materials are able to meet established
criteria for daily cover under various operational and climatic
conditions- In addition, although dependent on site specificity said
the particular alternative used, certain .materials are more effective
than soil as a daily cover, especially with respect to control of
vector access, blowing litter and odor, and the minimization of
moisture infiltration.
The effectiveness of ADCWs is dependent on proper landfill working face
preparation and operator proficiency during application or placement.
climatic conditions will also affect the choice of alternative coror
material, the method of application and its effectiveness as' daily
cover.
Evaluation of the effectiveness of ADCMs in meeting operational and
regulatory criteria for daily cover is generally based on subjective
comparisons with soil cover. Therefore, the absence .of consensus
performance standards for the evaluation of alternative daily cover
materials limits their selection and the determination of their
relative effectiveness under various operational and "climatic
conditions.
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Based on -these findings, it is recoaaaended that:
The use of ADCMs by landfill owners/operators and regulatory
authorities should be considered and integrated during design,
construction and operation of landfills.
Consensus performance-based standards should be established to permit
objective evaluations of the short-term and long-term effectiveness and
suitability of ADCMs.
Development of training and certification programs, instituted by
coordination between manufacturers of ADCMs and the regulatory and user
communities, would enhance the proper selection and application of
ADCMs.
- Opportunities to further improve the environmental and operational
acceptability of ADCMs with regard to formulation or fabrication and/or
application should be pursued.
The feasibility of developing a. procedure to grant State-wide approval
for the use of specific ADCKs, based pn pertinent performance data
and/or selected site-specific demonstrations, should be evaluated.
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CONTENTS
Disclaimer _ ,.
Foreword * " ' " _ "*""..^
Abstract " 1*1
*••••••••«.»•••..» iv
Summary .
Figures . | \ ' ' ' ' ."." ".!."""*" va ±±
Tables V3.ii
Acknowledgements " " ..^
1. Introduction ..;.... 1
2. Methods and Procedures ...1. 2
3. Functions, Requirements and Alternatives of Daily Cover, at
Landfill Disposal Sites . ... 4
Criteria for daily cover ...... .4
Daily cover regulatory requirements 4
Soil as a dally cover ................... 5
Alternative materials as daily cover .......... 6
4, Commercially available Alternative Daily Cover
Materials , §
Foam products 9
Spray-On products ., ...........36
Geosynthetic products . , .....56
5. Indigenous Materials ....... 97
General considerations .................97
Currently used indigenous materials . . . . . ... . . .98
6. Site Operation and Management Implications of Using
Alternative Katerials as Daily Cover 106
Impact on landfill capacity lOfi
Impact on soil requirements IDS
Operational cost considerations ... 107
Application considerations . 10?
Effectiveness as daily cover ..... 108
Duration of cover ................... no
Impact of clisiatic conditions Ill
Potential impact on leachate end landfill environment . 112
Site requirements and operational considerations ... 112
7. Conclusions and Reeosmaandations 115
Conclusions ...i,...- 115
Recommendations 116
S. References 117
9. Appendices
A. Manufacturers of commercially available alternative
daily cover materials with 1992 contacts ....... 120
B. Summary of information requested from manufacturers
and landfill owners/operators 123
C. Summaries of user/manufacturer experience with ADCKs . 126
10. Glossary
153
vii
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FIGURES
Number ' . pa.qe
1. ROSMAR« Bulk Storage and Dilution (BSB) unit 18
2. RUSMAR® self-propelled Pneumatic Foam Unit (PFU) ...... 18
3. Close-up view of RUSMfiR® PFU dual-directional
manifold system ..... 19
4. ROSMAR® PF0 applying 6-in. {15-cm) thick foam layer
onto -working face ..................... 3.9
5. RUSHAR® foam immediately after application of a
6-in. {.15-cm> thick layer 21
6... RUSMAR® foam 16-18 hr, i.e., overnight, after application
of a 6-in. (15-cm) thick layer ...... 21
7. SaniFoamw self-propelled foam application unit {SP-750}
applying 2- to 3-in. (5- to 7.5-cm) thick layer of
foam onto a working face 24
S. SaniFoam'" pull-behind {towed} foam application, unit '
{PB-25QD) • 25
9. Close-up view of SaniFoam"1 Jjmaediately ' after application
of a 2-in, (5-cm) tnick layer 27
10. SaniFoam"" three days after application of a 2- to 3-in.
(5- to 7.5-cm) thick layer 28
11. TerraFoam" self-propelled foam application unit {TerraH&C}
equipped wita front-^Ksanted foam discharge manifold .... 30
12. Application of 6-in. {15-cm} layer of TerraFoam™ onto
a working face ; ., 32
13. Close-up view of TerraFoamm immediately after application
of a 6-in. {15-cm) thick layer 32
14. TerraFoam* 22-24 hr after application of a 6-in. (IS-ca)
thick layer and exposure to moderate rainfall durinc a.
thunderstorm .... ......."...„ 34
15. skid-mounted ConCover® &ll-Purpose Sprayer (CAPS) 46
16. Application of ConCover® slurry onto a working face usinc
trailer-mounted CAPS " 45
viii
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FIGURES (continued)
Number - . . Page
17. Close-up view of ConCover* slurry immediately after
application of a 1/16- to 1/S-in. (O.32- to 0.64-cm)
thick layer 47
IS. . ConCover* 6-7 days after application onto the working face
of a hazardous waste landfill ..... 47
19. ?osi-Shellm mobile sprayer (early model) * 53
20. Application of Posi—Shell"" slurry with spraygun mounted
on mobile sprayer 53
21. Close—up view of Posi—Shell™ slurry immediately after
application of a 1/4- to 1/2-in. (0.64- to 1.27-cm)
thick layer ..'.... 54
22. Close-up view of Posi—Shell"1 S-10 days after application
of a 1/2-in. (1.27-cm) thick layer 55
23. " Lifting bar, attached to excavator bucket, being used to
place 48 by 50 ft (14.6 by 15.3 m) Airspace Saver" panel
(Can also be used to place COVERXECH C-440 panels) .... 78
24. Leading edge of panel being lowered onto working face
by excavator equipped with lifting bar 78
25. Trailing edge of panel being detached from lifting
bar after extension of panel over working fa.ce ...... 79
26. . A 10,OOO ft2 (930 m2} working face covered with panels
placed using lifting bar ................. 79
27. Hydraulically operated reel used to place and retrieve
75 by 150 ft (22.9 by 45.7 m) CORKIER panels . S4
28. Panel being unrolled from reel during placement
onto ash/sludge working face . . . 85
29. Manual extension of panel over working face
after unrolling from reel S5
30. Retrieval of panel by \xse of hydraulically
operated reel ........... . 86
ix
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11A.
TABLES
Number ' . '
1. Daily application considerations - foam cover products .... 10
2. Climatic considerations - foam cover products ........ 13
3. Operational considerations - foam cover products ...... 3.4
4. 1992 Materials and equipment costs - foam cover
products . 35
5. Daily application considerations - spray-on cover
. products --..•.....••........,....,... 37
6. Climatic considerations - spray-on cover products ...... 40
7. Operational considerations - spray—on cover products .... 41
8. 1992 Material and equipment costs - spray-on cover
products ,, . . 43
9A. Daily application considerations - geosynthetic cover
products {Airspace Saver'*, Aqua-Shed" and COSMIER) .... 57
9B. Daily application, considerations - geosynthetie cover
products (COTERSSCH C-44Q, FabriSoil® and Griff olyn®) ... 59
9C. Daily application considerations - geosynthetic cover
products (Polyfelt ZOO10, SaniCoverm and Typar®) ..... 61
10A. Climatic considerations - geosynthetic cover products
(Airspace Saver", Aqua-Shed3' and CQ&MZER) ......... 63
10B. Climatic considerations - geosynthetic cover products
{COVSB2ECH C-440, FabriSoil® and Griffolyn®} 54
Climatic considerations — geosynthetic cover products
(Polyfelt ZOQ10, SaniCover" and Typar®} 65
Operational considerations - geosynthetic cover products
(Airspace Saver", Aqua-Shedwr CORMIER, COVERTECH C-440,
and FabriSoil®) ss
11B. Operational considerations - geosynthetic cover products
{Griffolyn®, Polyfelt X0010, SaniCover" and Typar*} .... 6S
12A, 1992 Material and eguipsaent costs - geosyntbetic cover
products (Airspace Saver*, Aqua-Shed" and CORMIER} .... 70
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Number
TABLES (continued)
Page
12B. 1992 Material and equipment costs - geosynthetic cover
products (COVERTECH C-440, FabriSoil® and Gnffolyn®) ... 71
12C 1992 Material and equipment costs - geosynthetic cover
products (Poly felt X0010, SaniCover1" and Typar®) ..... 72
13A Climatic considerations - indigenous materials (Ash-based
Materials, Automobile Recycling Fluff, Dredged Material
and Foundry Sand) ...... ...............
133 Climatic considerations - indigenous materials
(Green Waste /Compost, Contaminated Soil, Shredded
Tires and Sludges) .......... ... .......
operational considerations - indigenous materials
(Ash-based Materials, Autoaobile Recycling Fluff
Dredged Material and Foundry Sand) ......
14B Operational considerations - indigenous materials
(Green Waste/Compost, Contaminated Soil, Shredded
Tires and Sludges) ...... - ............. i°'i
APPENDICES
B-l Summary of 1992 information requested from manufacturers
of alternative daily cover materials ...... .....
B-2 Summary of 1992 information requested from landfill owners/
operators on the use and performance of alternative daily
cover materials ....... .............. * . •L
C-l. 1992 User/manufacturer experience - RUSMAR® (AC-645) .... 126 -
C-2. 1992 User/manufacturer experience - SaniFoam™ ........ 128
C-3. 1992 User /manufacturer experience - TerraFoam™ . ... . - - 12S
C-4. ' 1992 User /manufacturer experience - TopCoat"" . . ...... 130
c-5. 1992 User /manufacturer experience - ConCover® ........ 131
c-6. 1992 User/manufacturer experience - Land-Cover Formula 480 . 133
c_7o. 1992 User /manufacturer experience - Posi-Shell"* ....... 134
C-8, 1992 User /manufacturer experience - Airspace Saver™ ..... 135
C-9 . 1992 User /manufacturer experience. - Aqua-Shed1- ........ J-37
C-1G . 1992 User /manufacturer experience - CORMIER ...... - - - 138
C-ll. 1992 User /manufacturer experience - COVERTECH C-440 ..... 139
C-12. 1992 User/manufacturer experience - FabriSoil® ....... 140
c_13. 19S2 User /manufacturer experience - Griff olyn® ....... 142
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TABLES (continued)
Number ' . Page
C-14. 1992 User/manufacturer experience - Polyfelt ........ 143
C-15. 1992 User /manufacturer experience - SaniCover* . . T . . ~1 .~ 145
C-16. 1992 User/manufacturer experience - Typar® 148
C-17. 1992 User/manufacturer experience — Indigenous Materials . . 150
. xii
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ACKNOWLEDGEMENT S
Project support provided by the United States Environmental Protection Agency
and the Department of Civil Engineering at the University of Pittsburgh is
acknowledged. In addition, the authors wish to extend their appreciation to both
the manufacturers and distributors of commercially available alternative cover
materials, and the operators of landfills that were contacted during the conduct
of this investigation to provide information and/or share experiences. Special
thanks is also given to those landfill managers that granted site visit
privileges and the opportunity to observe and photograph the application and
performance of alternative cover materials.
Ms. Phyllis Scoggins, Administrative Secretary, is particularly acknowledged
for assistance in preparation of this report.
xiii
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SECTION 1
INTRODUCTION
^^^^
site management and use requirements.
Dailv cover placed on exposed wastes at the end of each operating day
shou]d functSn to control disease vectors, blowing litter, odors, scavenging,
and fires Daily cover material should also provide an aesthetically Phasing
Spearanc;, bJ usable and effective under various operating conditions, and not
impede the proper management of leachates and gases.
nrimarily due to its usual availability and tradition of use at
a. cornroercially available foams,
enviro™ent.lYp.r3pSttiv., .nd (2) to identify areas warranting
further consideration and development.
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, ' SECTION 2
METHODS AND PROCEDURES
To accomplish the project objectives, the various types of ADCMs currently
available and/or being used were identified, and available technical information
on their characteristics, use, and performance was evaluated. In addition,
landfill owners/operators and landfills where operational experience was
available on the use and performance of specific ADCMs were also interviewed or
visited.
To initially determine the various types of ADCMs available and/or being
used, a questionnaire was sent to State regulatory agencies, U.S. EPA regions,
known manufacturers and suppliers of ADCMs, solid waste management associations,
and owners/operators known to have experience with ADCMs. The questionnaire
requested identification of ADCMs being used/marketed, available information on
their use and performance, regulatory requirements regarding their use, and
points of contact for further follow-up or possible site visits. Based on
responses received, 16 commercially available ADCMs, including four foam, three
spray-on and nine geosynthetic products, and eight types of indigenous materials
were identified. A listing of the manufacturers of these products is provided
in Appendix A.
Information on each of the commercially available products, including
features and characteristics, material and equipment requirements, methods of
preparation and application, climatic and operational considerations, and
effectiveness as daily cover was subsequently obtained from manufacturers, usesrs
of these products, and available reports on specific products. Table B-l,
Appendix B, summarizes the information that was requested from manufacturers.
Furthermore, other studies and evaluations that have been conducted on the use
and performance of ADCMs (8, 16, 39, 40, 46) were also reviewed.
Landfill operators identified as having experience with various
commercially available ADCMs, as well as indigenous materials, were contacted or
visited. Site or operations managers at approximately 30 sites, including sites
operated by both large and small waste management firms, municipalities and
regional waste management authorities, were interviewed by telephone or in
conjunction with site visits. During these interviews, experiences regarding the
use, performance, benefits, climatic impacts, operational considerations, and
economic aspects of ADCMs were discussed. Whenever possible, several sites using
a particular ADCM were contacted. The type of information generally requested
from landfill operators is summarized in Table B-2, Appendix B.
Eleven site visits were conducted. These sites were primarily selected to
observe the use and performance of the different foam and spray-on products
currently available and the various methods being used to apply geosynthetic
covers. During these visits, in addition to observing the use and performance
of ADCMs, site and/or operations managers, equipment operators and laborers were
interviewed about their experiences with the particular product being used at the
site.
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Summaries of the information provided by manufacturer's representatives and
landfill managers and operators during telephone interviews, or based on
interviews and observations made during site visits, are presented in Appendix
C. Tables C-l through C-16 present summaries for the commercially available
products, and Table C-17 for indigenous materials. (In this report, references
to these summaries are identified by use of the designations for each specific
site in these tables, e.g., RM-l(C-l) refers to site RM-1 in Table C-l.)
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SECTION 3
FUNCTIONS, REQUIREMENTS AND ALTERNATIVES OF DAILY COVER
AT LANDFILL DISPOSAL SITES
3.1 CRITERIA FOR DAILY COVER
Daily cover is the material that is placed over the working face
of the landfilled solid waste at the end of each operating day, primarily for the
protection of human health and the environment, but also for aesthetic,
operational, and site use and management considerations. The specific functions
of daily cover, and hence the basis by which its effectiveness is determined,
include:
- Control of disease vectors through minimization of breeding areas
and access to birds and animals. This is accomplished by
controlling fly and other insect emergence, entrance, and breeding,
rodent burrowing for food and harborage, and by avoiding nuisances.
Control of blowing litter, noxious odors and other air emissions,
and scavenging, and providing an aesthetically pleasing appearance.
- Lessening the risk and spread of fires through reducing
combustibility, controlling air intrusion and providing waste
separation, i.e., a barrier to prevent the spread of fire within the
landfill.
- Control of water movement by increasing runoff to reduce
infiltration of rainwater and uncontrolled generation of leachates.
Control of gas movement to prevent lateral migration of landfill
gases.
In addition, various factors that impact on-site use and operations should
also be considered in assessing the effectiveness of cover materials. These
include: equipment operation under all potential climatic conditions; wind
erosion and dust control; and effects on equipment operation, subsidence, and
settling. It must also be recognized that determination of the effectiveness of
a daily cover in performing its functions is primarily subjective in that
consensus, quantitative performance-based standards have not been generally
established with few known exceptions, e.g., California (6).
3.2 DAILY COVER REGULATORY REQUIREMENTS
The placement and compaction of 6 in. (15 cm) of earthen material over the
working face at the end of the operating day is currently the accepted standard
for daily cover at landfills. This thickness of soil has been demonstrated as
effective in performing the necessary functions of daily cover. In recent years,
however, there has been an increased use of alternative materials which can also
provide the features of an effective daily cover.
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The recently promulgated Solid Waste Facility Disposal Criteria (40 CPR
Part 258) include specific requirements for cover material and stipulate that:
» owners and operators of MSWLF (Municipal Solid Waste Landfill) units must
cover disposed solid waste with six inches (sic) of earthen material at the end
of each operating day, or more frequent if necessary, to control disease vectors,
fires, odors, blowing litter, and scavenging." These criteria also state that:
"Alternative materials of alternative thickness (other than at least six inches
(sic) of earthen material) may be approved by the Director of an approved State
if the owner or operator demonstrates that the alternate material and thickness
control disease vectors, fires, odors, blowing litter, and scavenging without
presenting a threat to human health and the environment" (40 CFR Part 258, Para
258 21). Furthermore; these criteria permit the Director of an approved State
to grant temporary waivers of daily cover requirements if the owner or operator
demonstrates that there are extreme seasonal climatic conditions that would make
meeting such requirements impractical (18). Hence, the federal criteria permit
the use of alternative materials if approved by a State's Director, but only for
States with approved programs, i.e., if the State program for solid waste
disposal facilities (SWDF) is not approved by the EPA, use of alternative
materials is not permitted at landfills located within that State.
^ The use of alternative cover materials is currently permitted by most State
regulations, although specific State requirements will vary (6, 19, 25, 31, 33).
Generally, States allow a "suitable" material to be used in lieu of soil if it
can be demonstrated to be as effective as 6 in. (15 cm) of compacted soil in
controlling disease vectors, fires, odors, blowing litter, and scavenging. Most
State regulations also permit these alternative materials to be of an alternative
thickness. (Pennsylvania, which until recently required that alternative
materials also be 6 in. (15 cm) thick, was the only known exception.)
Furthermore, some States, e.g., California, also permit the use of performance
standards where alternative materials are evaluated based on their ability to
meet specific objective criteria established by the State for daily cover (6).
Use of ADCMs will usually require a modification to the SWDF's operating
permit. Typically, upon a request of the owner/operator, the regulatory agency
will grant temporary approval of a period of 3 to 6 months to demonstrate the
suitability of the alternative material as daily cover. During this period, the
facility will be required to provide specified documentation with respect to the
performance of the alternative material, climatic conditions, problems
encountered, etc. Upon completion of the demonstration and review of the
information provided, the State can grant a permit modification, which may
inclvide climatic and operational restrictions, to allow the use of the
alternative material.
In many States, even if one site within the same State has already received
regulatory approval for use of a specific ADCM, other landfills within that State
which may want to use the same ADCM are required to also demonstrate- its
effectiveness prior to receiving regulatory approval. Landfill owners/operators
have expressed an interest in having State regulatory agencies evaluate ADCMs and
grant state-wide approval for the use of those ADCMs that meet their established
criteria, with appropriate restrictions on their use, as necessary. They believe
this will facilitate their ability to obtain permit modifications ifor the use of
ADCMs that are acceptable to the state regulatory agency without necessarily
conducting extensive site-specific demonstrations as to their effectiveness.
3.3 SOIL AS A DAILY COVER
As stated above, soil remains the most commonly used material for daily
cover. At many landfills, soil is readily available. There are, however,
drawbacks that will affect the feasibility of using soil as daily cover. These
include the following:
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- Use of at least 6 in. (15 cm) of soil for daily cover consumes
valuable landfill space that could be otherwise used to dispose of
solid waste.
- At many landfills, soil suitable for daily cover is not available
on-site and must be transported to the site, thereby increasing
operational costs, traffic in and around the landfill, and
generation of dust.
- Adverse climatic conditions, such as rain or freezing temperatures,
also impact the use of soil, as such conditions make excavation,
transport and placement of a daily soil cover more difficult and
time consuming.
- The manpower and equipment retired to obtain, store and place soil
as daily cover material may not be the most economical use of these
resources.
- Certain soils used as daily cover may not be effective in shedding
rainwater from the working face, thereby increasing infiltration and
potential leachate production.
- The barriers created by 6-in. (15-cm) soil layers can impede the
vertical movement of leachate and gases within the landfill cells,
cause uncertain lateral migration, and thereby promote potential
health and environmental problems.
3.4 ALTERNATIVE MATERIALS AS DAILY COVER
In recent years, there has been a significant increase in the use of
alternative cover materials. Increased use of ADCMs is primarily attributed to
the operational, performance-related, and economic benefits the use of these
materials offers to the landfill owner/operator.
3.4.1 Considerations in Using Alternative Cover Materials
Although the benefits of using alternative cover materials will vary with
the material used, site-specific characteristics, and operational considerations,
these can include:
- Savings in landfill capacity, which will extend the useful life of
the landfill and permit additional revenues associated with these
space savings.
- Decreased requirements for soil cover, thereby conserving soil and
reducing dust generation and operational costs associated with the
movement and placement of soil cover.
- Ease of application under various climatic conditions while
requiring less time, equipment and personnel to place or apply.
- Increased effectiveness over soil in meeting site operational and
regulatory requirements for daily cover, including vector access
control, blowing litter and odor control, and minimization of
moisture infiltration.
- Improved opportunities for more effective leachate and gas
management by avoiding construction of intervening layers within the
landfill that could impede controlled movement and ultimate
treatment and disposal.
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However, other factors must be considered in finally determining the
feaaibiliS ™* suitability of using an alternative material as daily cover.
These include:
The effectiveness of the material in meeting operational and
regulatory requirements at the site under various climatic
conditions.
Cost of the alternative material or its constituents.
Cost of purchasing/leasing, operating, and maintaining application
equipment.
Requirements for material and equipment storage facilities and
utilities at the site.
Effect on site operations, personnel requirements, work schedules,
safety, and overall facility management.
3.4.2 Types of Alternative Cover Materials
The types of alternative daily cover materials that are currently being
used consist of either commercial products or indigenous materials. These are
briefly described below and discussed in more detail in subsequent sections.
can be divided into three distinct groups
based onomposition, method of application, and general performance: foams,
spray-ons, and geosynthetics.
Foams— Foam ADCMs are applied to the working face in 2- to 6-in. (5- to
15-cm) laffrs, dependent on the product being used and regulatory requirements,
using* foam generation and application equipment specifically designed for that
particular foam. Both hardening and nonhardening foams are currently Bailable.
These foam layers are effectively destroyed by the placement of additional wastes
on Xe next operating day. (Foam ADCMs are discussed in more detail in Section
4.1.)
(Spray-on ADCMs are discussed in more detail
on the next operating day.
in Section 4.2.)
Geosvnthetics— Geosynthetic ADCMs consist of various types of
geosynthetlc materials that have either been developed or adapted f or r use as a
daily cover material. Panels fabricated from these materials are placed over the
working face at the end of the day, and retrieved prior to the start of the next
operating day. Some landfills have designed and fabricated «P£^ •'J^g^
facilitate the placement and retrieval of panels. (Geosynthetic ADCMs are
discussed in more detail in Section 4.3.)
indigenous iais ^ ^ alternative d&.
types of locally available waste products (e.g., sludges, ash, contaminated
soils, shredded tires, green waste, etc.) that are placed onto the working face
in a manner similar to soil cover*. Many of these same materials require disposal
within landfills By demonstrating their feasibility as an alternative cover
material, which in some cases may require physical modification (e.g.,
-------
shredding), chemical treatment (e.g., sludge-derived products), or increased
monitoring (e.g., contaminated soils), sites have obtained regulatory approval
for their use as daily cover material. (Indigenous materials are discussed in
more detail in Section 5.)
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SECTION 4
COMMERCIALLY AVAILABLE ALTERNATIVE DAILY COVER MATERIALS
Although some ADCMs have been commercially available for over 10 years,
there has been a significant increase in the development, marketing and use of
various types of ADCMs in recent years. This has been prompted by the interest
of landfill owners/operators in ways to optimize available landfill capacity and
operate the sites more efficiently and economically. In addition, there has been
a recognition by various manufacturers that their products, which may have been
developed for other purposes, may also be marketable as an effective daily cover
for landfills.
This section of the report presents 1992 operational, climatic,
performance, and economic considerations for each of the commercial products
identified during this investigation (See Appendix A), including: materials and
equipment required; preparation and application methods; site conditions;
performance; and costs. (The order of presentation does not constitute or imply
any preferential ranking of these products.)
4.1 FOAM PRODUCTS
The following foam products were identified and evaluated during this
study; RUSMAR® (AC-645), SaniFoam1", TerraFoam"1, and Topcoat™. All these
products, except TopCoat™, which has only been recently developed for commercial
markets, are currently being used at various landfills. Site visits were
conducted to observe the use and performance of these products (except TopCoat")"
under actual field conditions. Following general considerations related to the
use of foam products, each is discussed in more detail in subsequent sub-
sections. Application, climatic and operational considerations related to the
use of these products are summarized in Tables 1 through 3, respectively.
Material and equipment costs are presented in Table 4.
4.1.1 General Considerations.
Common aspects related to application, climatic, and operational
considerations of foam products are presented in this section. Procedures or
considerations specific to a particular product are presented in subsequent
sections.
Application Considerations—
Each of these foam products, with the exception of TopCoat™ which is
applied with a sprayer similar to a hydroseeder, is applied with equipment that
either sprays or lays, e.g., TerraFoam™, a foam layer of sufficient thickness to
cover the wastes as the equipment traverses the working face. Operator care
taken to ensure that foam is applied in a continuous layer that completely covers
the wastes helps determine its effectiveness in controlling vectors, blowing
litter, and odor and other air emissions.
Although regulatory requirements may stipulate a minimum thickness, the
thickness of foam that must actually be applied to effectively cover the working
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face is primarily dependent on the smoothness of the working face, i.e, care
taken in working face preparation prior to foam application. Since the time
required to apply foam and the cost of foam is directly proportional to the
thickness at which it must be applied, working face preparation is an important
operational and economic consideration when using these products.
Even though foams are typically applied at a thickness of 2 to 6 in. (5 to
15 cm), based on site-specific operational and regulatory requirements, the
structure of these covers is subsequently destroyed by the placement and
compaction of wastes the following operational day. Consequently, negligible
landfill capacity is used when foams are used as a daily cover, regardless of the
thickness at which they are applied.
Climatic Considerations—
Since climatic considerations related to the use of foam products vary
among the different products that are currently available, these considerations
are presented in the subsequent sections which address each specific product.
Operational Considerations—
Vector Control— The sticky consistency of nonhardening foams, find
hardening foams when initially applied, deters insects and birds from landing
onto the working face and animals from digging. When cured, hardening foams form
a resilient layer which prevents access to the waste by birds and animals. Foams
also diminish a vector's ability to sense food sources among the wastes.
Blowing Litter and Odor Control— Foams readily adhere to the wastes when
applied, thereby containing them and preventing blowing litter. Odors and other
emissions from the working face are also controlled by the foam layer. In
addition, the use of foams generally results in an aesthetically pleasing
appearance.
Fire Retardation— Nonhardening foams are noncombustible. When applied,
all foams form a barrier that minimizes the transfer of atmospheric oxygen to the
working face. However, no barrier to the potential spread of fire within the
landfill will remain, since the foam layer is usually destroyed by the placement
of wastes onto the working face the next operating day.
Minimization of Moisture Infiltration— When applied to form a continuous
layer, hardening foams, once cured, are able to shed rainwater from the working
face. Nonhardening foams, although able to withstand rain events to varying
degrees, are not effective at shedding rainwater.
Dust Control— When applied to the working face or surrounding soil, foams
adhere to and contain materials prone to dusting. In addition, the use of foams
eliminates the need to transport and place soil cover, reducing that element of
dust generation.
Leachate and Gas Control— Since foams are effectively destroyed after
placement of wastes the next operating day, the freedom of movement of leachates
and gases within the landfill is not curtailed.
4.1.2 RUSMAR® Series AC-645 Foam.
RUSMAR®'s Series AC-645 long-duration foam, manufactured by RUSMAR Inc.,
West Chester, PA, consists of a viscous foam with a consistency of light shaving
cream. The nonhardening foam, designed for application with RUSMAR® Pneumatic
Foam Units (PFUs), is applied to the working face in a 3- to 6-in. (5- to 15-cm)
layer depending upon operational and regulatory requirements, and provides daily
cover for up to 20 hr during periods when rain is not anticipated. This product
is currently being used at landfills located in Pennsylvania and Delaware.
16
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Materials and Equipment—
The foam consists of a proprietary concentrate which is diluted-with water
and applied to the working face by pressurized air using a PFU to form a
continuous, smooth layer of nonhardening foam. According to the manufacturer,
the foam, consisting of an air-entrained aqueous solution which combines soaps
and surfactants, is nontoxic, nonhazardous and biodegradable. When applied, its
composition is approximately 96% air, 3.9% water and 0.1% active, ingredients.
The foam is also noncombustible and, although not sold as a fire suppressant, is
able to extinguish flames. Although most often applied as a white foam, other
colors (gray, brown and black) are also available. The foam and certain aspects
of the foam generation and application equipment are patented.
The concentrate, which has no shelf-life restrictions, is stored in a
RUSMAR® Bulk Storage and Dilution (BSD) unit consisting of a storage tank with
built-in dilution system designed for on-site storage of bulk quantities of foam
concentrate (Figure 1). This tank is insulated and heat-traced (i.e., heating
wires are placed within the tank's walls) to permit year-round outside storage
under all climatic conditions. (The manufacturer has indicated that if the
concentrate were to freeze, its characteristics or performance would not be
affected when subsequently thawed).
The BSD unit, which requires both an electrical and water source, permits
both foam product and dilution water to be transferred and metered into the
solution storage tank aboard the PFU. This automated system includes
microprocessor-controlled transfer pumps and metering devices which mix and
deliver the concentrate and dilution water at a preprogrammed dilution ratio.
Although the mixture does not present any occupational risk, the transfer hose's
connections, which are compatible with the PFU, are designed to avoid worker
contact with the concentrate. The BSD unit has a capacity of 7000 gal (26,500
L) and is capable of transferring the mixed solution at a rate up to 120 gpm (454
L/min). The manufacturer also provides an insulated and heated water storage
tank for dilution water, if required.
RUSMAR® manufactures several models of PFUs with different on-board storage
capacities and application rates (42). These self-propelled and towed units are
self-contained foam generating systems, incorporating proprietary foam generation
technology.
The self-propelled PFUs (Figure 2) include diesel-driven hydraulics,
Caterpillar™ tracks and drive assembly, solution storage tank, air compressor,
freeze protection system, manifold distribution system, and handheld hoses. The
freezes protection system permits outside storage of the PFU (an electrical source
is required) under all climatic conditions. The manifold system distributes foam
in a bi-directional manner (Figure 3), leaving a uniform covering of foam (Figure
4). These units range in storage tank capacity from 1,600 to 3,000 gal (6,050
to 11,350 L). Their application rates range from 400 to 1,200 ft/min (37 to 112
m2/min), with coverage ranging from 18,000 to 35,000 ft2 (1,670 to 3,250 m2) per
tankload, depending on the thickness of foam applied (42). All foaming
functions, except handheld hose applications, are controlled from the cab by the
equipment operator, thereby reducing operator exposure. A video camera mounted
on the rear of the unit above the manifold allows the operator to view the
application of foam from the cab.
The portable (towed) foam generation systems include air compressors,
solution storage tank, pumps, hosing, and nozzles. With these models, foam is
applied using handheld hoses. The storage capacities of these units range from
400 to 1,600 gal (1,500 to 6,050 L). Application rates range from 300 to (500
ft2/min (28 to 56 m2/min), with coverage ranging from 6,000 to 24,000 ft (557 to
2,23O m2) per tankload, also depending on the thickness of foam applied (42).
On-site training is provided by the manufacturer on the preparation and
application of the foam, and the operation and maintenance of the equipment.
17
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^ v<
Figure 1. RUSMAR® Bulk Storage and Dilution (BSD)
Unit.
Figure 2. RUSMAR® self-propelled Pneumatic Foam Unit
(PFU).
18
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Figure 3. Close-up view of RUSMAR®, PFU dual-
directional manifold system.
Figure 4. RUSMAR® PFU applying a 6-in. (15-cm) thick
foam layer onto a working face.
19
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Unique or special operator skills are not required to perform the necessary tasks
associated with this equipment. Users have indicated that full proficiency in
the preparation and application of the foam is attained within 1 to 2 weeks.
RUSMARfli> also provides long-term service and maintenance contracts for both the
BSD and PFUs.
Preparation and Application— ;
Preparation for the application of foam is accomplished by transferring
foam concentrate mixed with dilution water from the BSD into the solution storage
tank aboard the PFU. Since the BSD unit is insulated and heat-traced, and the
PFUs are equipped with freeze protection systems, these functions can be
performed under all climatic conditions. Transfer operations will typically
require 15 min to accomplish; to fill the largest capacity PFU (Model 3000/120),
the tratnsfer operation may take up to 30 min. Once the storage tank is filled,
the unit is driven or towed to the working face. Alternatively, if operational
conditions warrant, e.g., a long distance between the preparation area and the
working face, a tanker truck can be used to transport the mixture from the BSD
unit to the PFU.
At the working face, the foam is typically applied in a 3-in. (7.5-cm)
thick layer which is considered to be sufficient to provide continuous, optical
coverage, i.e, visually covers the waste. According to the manufacturer, 1 gal
(3.8 L) of the foam concentrate and water mixture will generate sufficient foam
to cover a 10 ft (0.9 m) area with a 3-in. (7.5-cm) thick layer. A thicker
layer, e.g., 6 in. (15 cm), can also be applied if necessary to meet regulatory
requirements (Figure 5). For the self-propelled PFUs, the thickness of the foam
layer Is controlled by the speed at which the PFU traverses the working face.
The operator at one site indicated that it typically' requires 2 to 3 hr to
prepare for and apply a 6-in. (15-cm) thick foam layer to a 40,000 to 50,000 ft2
(3,720 to 4,650 m) working face (see user/manufacturer experience summary for
site RM-1, Table C-l, i.e., (RM-l(C-l)).
As is also the case with other foam or slurry spray-on products, it is
desirable to have a smooth working face prior to the application of the foam.
One site indicated that by traversing the working face with a tracked vehicle,
such as a dozer, upon completion of compaction of the working face, but prior to
application of the foam, coverage of the waste by the foam was improved and less
touch-up by the handheld hose was required (RM-l(C-l)).
Once applied, the foam can remain as an effective cover for 15 to 20 hr,
i.e., overnight (Figure 6). Since the foam usually remains effective for 20 hr,
it cannot be used as a daily cover if additional wastes or other cover material
are not placed onto the working face within this period of time, i.e., its use
is not permitted over weekends. Application considerations are summarized in
Table 1. •
Impact of Climatic Conditions--
Moderate or heavy rainfall is purported to be the only climatic condition
that will impact the use of RUSMAR® AC-645 foam. Hence, the manufacturer does
not recommend the use of this product when such conditions exist or are expected
to occur during the period that the foam is to be used as a daily cover. Under
such conditions, the foam can "wash out" and possibly no longer remain effective
as a cover material.
Under all other climatic conditions, however, including light rain or
drizzle, snow, wind, and hot and sub-freezing temperatures, the foam remains an
effective cover for up to 20 hr. These climatic conditions also do not adversely
impact the ability to apply the foam to the working face. This has been
substantiated by users of this foam under these types of climatic conditions (RM-
l(C-l), RM-2(C-1)). Climatic considerations related to the use of RUSMAR® foam
are summarized in Table 2.
20
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Photo courtesy of RUSMAR, Inc.
Figure 5. RUSMAR® foam immediately after application
of a 6-in. (15-cm) thick layer.
Photo courtesy of RUSMAR, fcc.
Figure 6. RUSMAR® foam 16-18 hr, i.e., overnight,
after,application of a 6-in. (15-cm) thick
layer.
21
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Performance— • <
RUSMAR® AC-645 foam is presently being used by landfills located in
Pennsylvania and Delaware. At a landfill operated by the Delaware Solid Waste
Authority^near Dover, DE, the foam has been used on a continuous basis since
January 1990 and has satisfactorily met the regulatory criteria for daily cover
when it was applied as recommended by the manufacturer to a minimum thickness of
J in. (7.5 cm), or to provide optical coverage of the waste (RM-2(C-1M At
various sites located in Pennsylvania, the foam is applied as a 6-in. (15-cm)
thick layer, as required by State regulations at the time their permits were
issued. One site has been using the foam since December 1990 and has been able
to meet all regulatory criteria for daily cover (RM-l(C-2)). Operational
considerations related to the use of RUSMAR* are summarized in Table 3.
When the foam is being applied with self-propelled units, the dual-
directional nozzles on the manifold, and their relative closeness to the working
face, allows the foam to be applied onto the waste with sufficient velocity to
both cause it to readily adhere to the waste and to fill the gaps of the waste's
irregular surface (Figure 3). This appears to greatly improve the consistency
and uniformity of coverage of the waste with the foam, and minimizes the effect
of wind during application (RM-l(C-l)).
.. ^The foam's sticky consistency allows it to adhere to waste surfaces and
thereby effectively trap lightweight items such as paper and plastics pronc=> to
becoming windblown litter. Because of its ability to trap windblown litter, one
operator reported occasionally using the foam specifically for that purpose,
applying foam on the downwind side of the working face on windy days to
complement the litter screens (RM-l(C-l)).
The foam has been reported to be especially effective for controlling odors
and other emissions at the working face (RM-l(C-l)). An on-site evaluation has
been conducted by RUSMAR, Inc. to determine odor, volatile organic compound, and
semi-volatile organic compound control efficiencies of RUSMAR® foam, soil cover,
and selected geosynthetics (Airspace Saver"1, FabriSoil® and Griffolyn®) at the
working face of a municipal solid waste landfill (22). Panels of these
geosynthetics (15 by 15 ft (4.6 by 4.6 m)) were placed onto the compacted working
face at the end of the operating day. A similar size area was covered with a 6-
in. {15-cm) layer of RUSMAR® foam, and the remainder bf the working face was
covered with soil. Emissions were measured at the center of the panels and foam
layer, and also the adjacent 9-in. (22.5-cm) soil cover, both immediately after
application and the following morning (14 hr later). Results indicated foam
emission control efficiencies of 98% for odors and of 100% for both methane 'and
total nonmethane hydrocarbons (TNMHC) immediately after placement of the foam.
Similar efficiencies (odor, 99%; methane, 100%; and TNMHC, 100%) were measured
after the foam had been in place overnight. Measurements were also made of
specific organic compounds, including freons, methylene chloride, 1,3,1-
trichloromethane, tetrachloroethane, trimethylbenzenes, 1,4-dichlorobenzene,
toluene, xylenes, and ethylbenzene. Emission control efficiencies were 100% for
all compounds immediately after placement of the foam, and remained 100% for all
compounds except Freon 11 (68%), Freon 12 (75%) and toluene (95%) the following
morning. By comparison, soil cover emission control efficiencies for odorT
methane and TNMHC were 99%, 0% and 93%, respectively, both immediately after
placement and the following morning. (Analyses for specific organic compounds
were not performed on these samples.) Control efficiencies reported for the
geosynthetics are presented in Section 4.3.1.
The foam is nonflammable and will not support combustion. It was
successfully used to suppress a fire on landfill equipment at a site which uses
the foam (RM-l(C-l)). (The manufacturer has indicated, however, that the foam is
not being marketed as a fire suppressant, but only as a daily cover material.)
To date, regulatory approval for the use of RUSMAR® foam has been obtained
by several sites in Pennsylvania and one site in Delaware. To meet regulatory
; 22
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requirements, the foam must be applied at a minimum thickness, i.e., 3 to 4 in.
(7.5 to 10 cm) in Delaware and a minimum of 6 in. (15 cm) in Pennsylvania, and
it cannot be used if rain is anticipated prior to the next operating day and for
periods of time to exceed 24 hr.
Costs—
Costs associated with the use of RUSMAR® AC-645 foam as a daily cover
include the cost of the foam concentrate and the BSD unit, water storage tank,
if required, and PFU. These costs are summarized in Table 4. According to the
manufacturer, equipment costs, including the purchase or lease of the BSD unit
and PFU,, and related operational and maintenance costs, will average from $0.0055-
0.01/ft ($0.05-0.11/m2), based on amortized costs over a 10-yr period for
equipment that is properly sized for the landfill. This includes costs for
maintenance support provided by the manufacturer.
The operator of a site using the foam for approximately 18 mo has estimated
average costs, including foam concentrate, amortized equipment cost, and
maintenance support, of $0.10-0.12/ft2 ($1.08-1.29/m ) to apply a 6-in. (15-cm)
thick cover to a 40,000 to 50,000 ft2 (3,700 to 4,650 m2) working face (RM-1(C-
1))..
4.1.3 SaniFoam1".
SaniFoam1" Synthetic Daily Cover (SDC), marketed by 3M Environmental
Protection Products (3M), St. Paul, MN, is a specially formulated polyamino foam
that forms an expandable foam blanket which is sprayed onto the working face In
a 1- to 2-in. (2.5- to 5-cm) layer by a mobile sprayer. Upon application to .the
waste, the foam cures to a consistency resembling Styrofoam™. Once it cures, the
foam can last for several days under all climatic conditions. This product,
which has also been known as "Saniblanket" and "SM-Foam", has been used as an
alternative .cover material since the early 1980's. It continues to be used at
landfills located throughout the United States, as well as at several overseas
locations.
Materials and Equipment—
The materials used in the formulation of the foam, resin stabilizer and
foam concentrate, are proprietary chemicals available from 3M. These are
typically delivered to sites in 55-gal (208-L) drum sets, although bulk delivery
of the materials is also available. The materials must be properly stored to
prevent freezing and exposure to high temperatures (> 100°F (38 C)). The resin
stabilizer has a shelf-life of approximately 3 mo.
Application equipment specifically designed to apply these materials Is
available from the manufacturer. Several models of different capabilities and
capacities are available. All units include diesel-powered air compressors, air
diaphragm material transfer pumps, storage tanks, all-weather enclosures and hot
water flush systems to flush the spray nozzles after each use. Patents exist on
the formulation of the foam and certain features of the application equipment,
e.g., compaction roller.
The largest system available is the self-propelled applicator SP-750D
(Figure 7). Mounted on a Volvo 35-ton chassis, this single operator unit
features a hydraulically operated (both horizontally and vertically) dual
directional spraybar to provide consistent and even application,, a rotating
spraygun for pinpoint application, and a 7-ft (2.1-m) wide rubber coated steel
roller to provide a smooth service for more even application (44). A rear
mounted video camera permits the operator to view the spraybar from the cab. All
foaming functions are also controlled by the operator from this location, thereby
minimizing operator exposure. According to the manufacturer, this system has the
capacity to provide surface coverage up to 90,000 ft (8,360 m ) per application,
i.e., without refilling the storage tanks,' dependent on the thickness of foam
applied. . ;
23
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Figure 7.
Kioto courtesy of 3M
SaniFoam™ self-propelled foam application
unit (SP-750) applying a 2- to 3-in. (5- to
7.5-cm) thick foam layer onto a working
face.
3M also manufactures two pull-behind units, the PB-250D (Figure 8) and PB-
375D (44). Similar in design and operation, but of different capacities, these
units feature an 8-nozzle dual directional spraybar assembly, handheld hose
applicators, and steel rollers for transport and compaction. Because these units
can weight up to 28,000 Ib (12,700 kg) for the PD-250D and 42,000 Ib (19,050 kg)
for the PB-375D when fully loaded, they are typically towed by a dozer during
foaming operations, since compactors are not considered powerful enough to tow
these units. Two operators,:one to operate the dozer and the other to control
the foaming functions, are required for foam application using these systems.
According to the manufacturer, the PB-250D and PB-375D units are capable of
providing coverage up to 20,000 ft2 (1,860 m2) and 40,000 ft2 (3,720 m2) per
application, respectively, dependent on the thickness of foam applied. A special
hitch, may need to be installed on the equipment used for towing these systems.
For small-volume landfills and smaller applications, a trailer mounted
handheld hose applicator, Model H-125D, is available (44). This system features
a 100-ft (30.5-m) delivery line for applying the foam and is, according to the
manufacturer, capable of providing coverage up to 10,000 ft2 (930 m2). Using this
system, which is towed to the working face, the operator manually sprays foam
onto the waste with the handheld hose.
Although foam application can be performed at temperatures well below
freezing, storage facilities are required to protect the equipment from exposure
to freezing temperatures when not in use. Such facilities are also necessary for
storage of the resin stabilizer and foam concentrate during freezing weather.
24
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*""^SiS^^^^^^
-., ,-.i_ ....-T,..-li_i«ji^-.-=--?-*!?S^'s^S:.:£.r.*-Bl4S3ij3
^*mii^^-^^.
Figure 8. SaniFoam™ pull-behind (towed) foam
application unit (PB-250D).
° ^iS1 °Perator skills are not required to perform the necessary
•<- 4- ^ * thS US? °f this shipment. The manufacturer provides
of eoment andrttning tO la.n.dfi11 Personnel on the operation and maintenance
of equipment, and the preparation and application of foam. Such training,
C° nducted.over ??r.a 1- t° 2-wk period, has been considered sufficient
^^ Prof iciency in the various tasks associated with applying
Preparation and Application —
™™ ln preparation for foam application, the resin stabilizer and foam
concentrate are placed in separate storage tanks aboard the foaming unit The
£o^nrn£rat» mUSt bS diluted wifch water, as it is placed into the onboard
storage tank. Hence, a pressurized water source or storage tank is required on
S£U™«- C°i Kr4-KCltma^eS' Precautions must be taken to ensure that the
temperatures of both chemicals and dilution water are sufficiently high to allow
the polymerization reaction between these chemicals to properly occur when thev
of\he "S ?"r1^ ^H^i0*: Th^ ""ay require inside, ?os?iblj heated? storage
of the application unit, both during preparation and when it is not in use. The
w^kin^ -f°r fc^S fillin9 operation will vary with site and the size of
«°S ?+ ^3~:e" the afea t0 be covered during the application. Operators at
some sites that use SaniFoam™ have indicated that preparation and eauipment
maintenance typically requires 4 hr/day (SF-l(C-2), SF-2(C-2)). e<3UiPme^t
W1len the tanks are filled, the units are driven or towed to the working
»ii i self7P^°Pelled ""its, the operator traverses the working face Ln
parallel rows, while controlling both the foaming unit's spraybar and spraygun
if «£££" «" tht^CSb- F°r Pull~behind ""its, the foam equipment operator? wo
is positioned at the rear of the unit above the spraybar, controls both the
foaming unit's spraybar and handheld hose, and directs the dozer operator frm
25
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4 n 7 c n , which also uses a PD-250D to apply 3- to
considerations are summarized in Table 1
reported to be 6.54 x 10'1 Ib DPT- ih /« CA i/v« period after application were
Impact of Climatic Conditions—
26
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• ••»"*.•••"*, "•. ~*-,'ssla±* •• "*--"r3t-**?~"-,.
"^"H
Figure 9. Close-up view of SaniFoam™ immediately
after application of a 2-in. (5-cm) thick
layer.
however, it is able to withstand moderate to heavy rainfall events without
significant deterioration in effectiveness as cover. Under all other climatic
conditions, including snow, wind, heat, and sub-freezing temperatures, SaniFoam™
has been demonstrated to be an effective cover for up to one week (SF-l{C-2)).
Climatic considerations related to the use of SaniFoam™ are summarized in Table
2.
With the self-propelled and pull-behind units, strong winds may impact the
application of foam to the working face by blowing foam as it is being sprayed
from the spraybar or distribution manifold nozzles located 2 to 3 ft (0.6 to 0.9
m) above the working face. This could result in incomplete and insufficient
coverage of the working face, requiring additional effort to "touch up" these
areas with the handheld hose (SF-l(C-2)).
Performance— .
SaniFoam™ has been available as an alternative daily cover material for
more than ten years and is being used at various landfills located throughout the
United States. Various studies and evaluations conducted on the use and
performance of SaniFoam™ have concluded that it can effectively meet established
criteria for daily cover when properly applied to provide a continuous cover over
the working face (11, 14, 15, 23, 45, 47). Operational considerations related
to the use of SaniFoam™ are summarized in Table 3. Site evaluations have also
indicated that previously applied foam cover which had been exposed for several
days (Figure 10) will continue to effectively contain the waste and prevent
blowing litter (11, 47). In addition, odors continue to be effectively
controlled (SF-l(C-2)).
SaniFoam1" is also capable of reducing the infiltration of rainwater if
applied as a continuous layer which completely covers the wastes, i.e., no gaps
27
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Photo courtesy of 3M
Figure 10. SaniFoam™ 3 days after application of a 2-
to 3-in. (5- to 7.5-cm) thick layer.
in the cover which could allow rainwater to infiltrate. Once the fqam has cured
and formed a resilient, relatively impermeable skin (usually 15 to 30 min),
infiltration of rainwater is reduced and runoff from the working face is
promoted. Because the foam is capable of adsorbing 60% of its volume as water,
moisture which may penetrate the foam's surface is also retained within the foam.
Depending upon the climatic conditions subsequent to the rain 'event, this
moisture can evaporate, further reducing moisture that would otherwise have
infiltrated into the landfill.
Because the foam resin contains trace quantities (approximately 0.7%) of
formaldehyde, there have been concerns regarding the potential for the presence
of formaldehyde in leachate. A study has been conducted to assess the potential
impact of formaldehyde on leachate stabilization processes within the landfill
and on the environment (36). Results of this study indicated that, although
formaldehyde can be leached from the foam, the presence of foam did not adversely
impact stabilization, the formaldehyde was degradable within the landfill, and
no adverse impacts attributable to the release of formaldehyde from the foam were
observed. Moreover, this study also indicated that various materials typically
present in municipal wastes, e.g, insulation and fabrics, could also contribute
to the presence of formaldehyde in leachates. In addition, at sites where
SaniFoam™ has been used as a daily cover material, and leachates are being
monitored for potential impacts due to the presence of formaldehyde, no adverse
impacts attributable to formaldehyde have been reported (11, 15).
Regulatory approval for the use of SaniFoam1" has been granted in many
States, usually following an on-site demonstration. Use of SaniFoam'" is
restricted in some States, e.g;, California, to nonrainy days (SF-2(C-2)), while
other States permit its use during light rain (SF-l(C-2)). Although studies and
user experiences have shown that the material can remain effective for up to 6
28
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to 8 days (1, 11, 47, SF-l(C-2)), most States limit its use to a shorter period
of time, e.g., next nonweekend operating day. Some States, e.g., New York and
Wisconsin, also require monitoring of the leachate for constituents that could
potentially leach from the foam, e.g., formaldehyde (11, 47, SF-l(C-2)).
Costs—
The costs associated with the use of SaniFoam1" include cost of foam
concentrate and resin stabilizer, and cost of the application equipment. These
costs are summarized in Table 4. In colder climates, it may also be necessary
to provide storage facilities for materials and the application equipment.
4.1.4 'TerraFoam"'
TerraFoam™, manufactured and marketed by National Foam, Inc., Environmental
Products Division (formerly Chubb Environmental Security, Inc.), Exton, PA since
1990, consists of a protein-based foam which has the consistency of a very thick
shaving cream or mousse. This nonhardening foam is generated and applied to the
working face with a specially designed foam application unit in a 3- to 6-in.
(7.5- to 15-cm) layer to provide daily cover for up to 72 hr under all climatic
conditions except heavy rain. This product is currently being used at landfills
located in Pennsylvania and California. , ' '
Materials and Equipment—
The foam is composed of a proprietary, protein hydrolysate concentrate
which is diluted with water (3% concentrate; 97% water) aboard the foam
application unit. This solution is then mixed with air and the resulting foam
applied to form a smooth, continuous 6-in. (15-cm) layer onto the working face.
The resulting foam is an off-white/tan color when first applied, and gradually
turns brown as it ages (24 to 72 hr). According to the manufacturer, the foam
is nonhazardous, nonreactive and biodegradable. It is also nonvolatile and
noncombu st ible
firefighting)
(TerraFoam"
formulation is based on foams used for
The foam concentrate is available in both 55-gal (208 L) drums and 250-gal
(946-L) containers, or can be delivered in bulk quantities by tanker truck. For
on-site storage of concentrate, various types, such as insulated or noninsulatedl,
and sizes of storage tanks to meet site-specific needs are available from the
manufacturer. The shelf-life of the concentrate is subject to both climatic and
storage conditions, but is purported to be at least six months. The manufacturer
has also indicated that, although measures should be taken to prevent the
concentrate from freezing, if frozen and subsequently thawed, the concentrate is
still useable.
To apply the foam, Chubb Environmental Security, Inc., has developed and
manufactures self-propelled foam application units called "TerraMAC" (10). These
units, which can be sized to meet site-specific requirements, consist of a prime
mover and chassis manufactured by Kabelco™, and a foaming platform including a
diesel-driven power unit, compressor, separate foam concentrate and water storage
tanks, pumps and hosing, hydraulic valving and a foam discharge manifold (Figure
11). The units are also equipped with both a turret-mounted spray nozzle
("monitor nozzle") and a 100-ft (30.5-m) reel-mounted hose for pinpoint focim
application in hard-to-reach areas.
The unit is designed to be multi-functional. When not being used to apply
foam, it can be used as a high pressure sprayer, suitable for cleaning landfill
.equipment and waste containers, a hydroseeder, or for fire-fighting. The unit's
design also incorporates an override capability, permitting either electronic or
hydraulic operation. All operational functions, except handheld hose foeim
application, are controlled from the operator's cab by the unit operator, thereby
reducing operator exposure.
29
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Figure 11. TerraFoam™ self-propelled' foam application
unit (TerraMAC) equipped with front-mounted
foam discharge manifold.
According to the manufacturer,
is capable of applvina
, this unit s capae
approximately 4,000 to 6,000 ft2 (372 to 557 m2) of a 6-in. (15-cm
layer before the 1,6OO gal (6,050 L) water storage tanks need to be
tan] ise^d to contain a sufficient amount of
UP t° four water storage tank refills, I.e., there is
foam concentrate storage capacity for up to 24,000 ft2 (2230 m2! of I
6-in (15-cm) thick foam layer.
=™T Chough this self-propelled unit is currently the only type of foam
application unit being used at sites, other units of varying capabilities and
capacities can also be provided by the manufacturer. A smaller fSTap^icat Jon
a handheld ho -^ Placed in,fide a <*™P truck, which will only applyPfoam from
for * ^?'f° '-t3 Cur5ently bein9 manufactured to meet operational requirements
for a secific Site. The manufacturer is also developing a rear-mounted soravbar
the **lf-Pr°Pelled foam application unit in plJce o? the f fSS
manifold, which is mounted on the front of the unit. This SDravbS
dly HP^ly a 22~ft (6-7-m) Wide laver of foam while traversinj^hl
face, and increase the area that can be covered with a 6-in. (15-cmT
thick layer to 12,000 ft2 (1,115 m2) per tankload of water. ( }
™~*.=n ?n~site training on the preparation and application of TerraFoam™, and the
th^;i°? a? r°Utinn,1 ; maintenance of the foam application unit, are provided by
the manufacturer. The equipment is designed for operation by heav£ eouiDment
SrIIic?enCva"n S^Cial ^^^ "^ re^ired- According to the mlnuIaSturer?
proficiency in the use of the foam application unit is attained in a week
Maintenance support is also available from the manufacturer.
30
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Preparation and Application—
Preparation for foam application is accomplished by filling both the
concentrate and water storage tanks aboard the foam application unit. Although
it is possible to fill the tank by gravity flow, foam concentrate is usually
pumped from drums/storage tanks into the concentrate storage tank using the
transfer pump provided for this purpose. The water storage tanks can be filled
by using a pressurized water source, gravity flow, or by pumping water from a
tank truck/reservoir using a transfer pump also provided for that purpose.
According to the manufacturer, it can require approximately 20 to 30 min to fill
these tanks.
Under cold weather conditions, appropriate precautions must be taken to
prevent these solutions from freezing after they are loaded into the storage
tanks and before foam application begins, such as circulating the solutions
within their respective tanks. The application equipment should also be stored
inside during freezing weather when not in use, as it is not equipped with freeze
protection. (The manufacturer has indicated that modifications could be made to
incorporate such protection.)
Once the storage tanks are filled, the self-propelled unit is driven to the
working face where the foam is applied in an approximately 10-ft (3-m) wide by
6-in. (15—cm) thick layer. Using the foam distribution manifold, the unit
applies foam by driving to the top edge of the working face and applying foam by
laying it onto the wastes as the unit backs down to the bottom edge (Figure 12).
Successive passes are made until the entire working face is covered. Areas which
cannot be readily reached by the foam application unit are covered by using the
turret-mounted "monitor" nozzle or handheld hose. The "monitor" nozzle, which
is mounted on top of the operator's cab and controlled by the operator from
inside the cab, is capable of spraying foam up to a distance of 100 ft (30.5 m).
The thickness of foam applied to the working face is controlled by the
speed at which the application unit traverses the working face.. The self-
propelled unit currently being used is capable of applying a 6—in. (15-cm) foam
layer (Figure 13) at a rate of 500 to 600 ft2/min (46 to 56 m2/min) . According
to the manufacturer, it requires approximately 30 to 40 min to cover 10,000 ft
(930 m2) of working face. This does not include the time required to initially
fill arid subsequently refill the storage tank. (It should be noted that the
manufacturer has demonstrated that a thinner foam layer, e.g., 3 in. (7.5 cm),
can effectively cover the working face, but regulatory requirements at the site
where TerraFoam™ is currently being used mandate use of a 6—in. (15-cm) layer.)
Depending on the size of the working face, i.e., if greater than 6,000 ft2
(557 m2), it may be necessary to refill the water and concentrate storage tanks
during placement of the foam cover. Although the time required for this will
vary with site conditions, such as the proximity of water source to the working
face, user experience indicates this typically requires 15 to 20 min. Use of the
spraybar currently being developed will reportedly increase the area that can be
covered per water tank refill to 12,000 ft (1,115 m2).
Upon completion of the foaming operation, water is used to flush the
hosing, discharge manifold, and nozzles. No further post-application cleanup is
required. Both concentrate and water can remain in the storage tanks until the
next operating day. In cold climates, however, appropriate measures must be
taken to protect the unit from exposure to freezing conditions, i.e., inside
storage. Application considerations are summarized in Table 1.
Impact of Climatic Conditions—
Heavy rain is reported to be the only climatic condition that adversely
impacts the use of TerraFoam™. Hence, the manufacturer does not recommend its
use when such conditions exist or are expected to occur during the period that
Terrafoam™ is to be used as a daily cover. According to the manufacturer and
31
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Figure 12. Application of a 6-in. (15-cm) thick layer
of TerraFoam™ onto a working face.
"'•"V.^f^.-;;-,
X^;i/;*;3r
-'•*»mu*>
s^':'::•::. '•
™-~*t?-'/.-ft"-.;'?rrii.-i.-'i*v- - -• • •.
• -v5.";-!"" ••.r^-^«iet?^'.,-"J
•l^; g-Z?i^''Zff."'5f-"-'-* ";
i jte;:«ci;-2SiSitsf*Ks;^:..'r f-r-
V' '' •-<:'. 'i
•ttiit';, ,-•>•:"-^
[y''"**^". •': 3
f»; "..j.*i!<$s*^~\
b-ZS^'-S \ . ',
Figure 13. Close-up view of TerraFoam™ immediately
after application of a 6-in. (15-cm) thick
layer.
32
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field observations, TerraFoam™ will slowly dissipate during very heavy rainfall
events, but it is fully capable of withstanding moderate rainfall such as may
occur during thunderstorms (Figure 14). This latter claim was substantiated
based on field observations made after a 24-hr period during which several
moderate rain events occurred (TF-2(C-3)).
Under all other climatic conditions, including snow, wind, heat and aub-
freezing temperatures, the foam has been demonstrated to remain effective for at
least 72 hr and up to 1 wk. These climatic conditions also do not impact on the
application of TerraFoam™ to the working face. Also, because the foam hats a
density 6 to 8 Ib/ft (96 to 128 kg/m ), it can, according to the manufacturer,
be effectively applied at winds up to 50 mph (80 km/hr). Climatic considerations
related to the use of TerraFoam™ are summarized in Table 2.
Performance—
Terrafoam™ has been used at several sites in Pennsylvania. One site has
used the foam since May 1991. It has been demonstrated to be an effective daily
cover that satisfactorily meets the regulatory criteria for daily cover when
applied as recommended by the manufacturer. The foam is not used if a heavy rain
event is anticipated during the period that it would be used as a daily cover.
Operational considerations related to the use of TerraFoam™ are summarized in
Table 3.
Because the foam is applied onto the working face in a smooth continuous
layer, it is able to completely cover the working face and effectively retain the
wastes to prevent them from being blown from the working face. Also, since
TerraFoam™ provides a continuous cover over the entire working face, it has been
reported to be particularly effective in suppressing odors emanating from the
working face (TF-2(C-3)). Laboratory studies have also been ' conducted to
demonstrate the effectiveness of TerraFoam™ at suppressing volatile hydrocarbon
emissions from contaminated soils (38). Results indicated that emission
suppression efficiencies remained greater than 98%, 96% and 95% for hexane,
toluene and xylene, respectively, after 4 1/2 days.
i
The manufacturer has indicated that, because of the relatively dense,
mousse—like consistency of Terrafoam™, and since it provides a continuous cover
over the working face, it will act as a barrier, similar to soil, during light
or moderate rainfall events and, consequently, decrease water infiltration into
the landfill. It is unclear, however, whether rainwater during such events is
actually shed from the working face, thereby reducing infiltration, or if it is
absorbed into the foam layer.
TerraFoam™ has been approved for use in California and Pennsylvania. At
Pennsylvania sites where "regulatory approval for the use of TerraFoam™ has been
granted, permit conditions stipulate that it cannot be used if heavy rain is
anticipated within 12 hours of application or if winds exceed 20 mph (32 km/hr)
(34). In addition, although operational experience has indicated that the foam
can provide an effective cover for 72 hr or longer (51, TF-l(C-3)), it may only
be used to provide cover for periods up to 24 hr at these sites.
Costs— :
Costs associated with the use of Terrafoam™ as a daily cover material
include the cost of foam concentrate and the foam application unit. These costs
are summarized in Table 4. Costs of on-site storage tanks, which will vary with
the type and capacity of the tank, were not available. In colder; climates, it
will also be necessary to provide for a storage facility to protect the
application unit and concentrate during freezing conditions.
33
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Figure 14. Close-up view of TerraFoam™ 22-24 hr after
application of a 6-in. (15-cra) thick layer
and exposure to moderate rainfall during a
thunderstorm.
4.1.5 TopCoat™
TopCoat™, manufactured by Central Fiber Corp., Wellsville, KS, consists of
a multicellular polymer, generated by the mixture of two liquid components, which
is sprayed onto the working face to form a foam layer that, according to the
manufacturer, resembles a cellular sponge. This product has only recently been
developed and marketed. Furthermore, modifications to the foam application unit
are presently on-going. As the product has only been used in limited field
tests, little operational and performance information is currently available.
Materials and Equipment— . , .
Two proprietary liquid components are used in the formulation of TopCoat™.
The manufacturer indicated that one of the components was considered corrosive
and required appropriate precautions during storage and handling (e.g., face
shield and gloves). Although there are no shelf-life restrictions, the liquid
components must be stored above 15°F (-9.5°C).
The foam application unit consists of a hydroseeder, specifically adapted
for the application of TopCoat™. The unit contains two separate tanks for on-
board storage of the liquid components, and a spray nozzle. Information
regarding unit capacity, application rate and coverage was not available. Also,
it is not known if special requirements or restrictions exist for application of
foam during sub-freezing conditions.
Preparation and Application— :
In preparation for foam application, the liquid components are placed in
separate storage tanks aboard the application unit. There is no dilution of
34
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these components with water prior to filling the storage tanks. To apply the
foam to the working face, the liquid components are mixed together in the spray
nozzle as the mixture is sprayed onto the working face. The foam expands and
cures within 15 to 30 min, depending upon climatic conditions, to form a "spongy
foam cover. According to the manufacturer, a 3- to 5-in. (7.5- to 12.7-cm)
layer, dependent upon working face compaction and smoothness, is applied to
ensure an effective cover. Subsequent to application, the tanks, hosing and
nozzle are flushed with water.
Application of the foam can be performed by one operator. Using two
operators, however, one driver and one to apply the foam, would permit more
efficient application, as the unit will need to be repositioned during
application to ensure complete coverage of the working face. Information
concerning the time required to prepare the unit, apply the foam, and clean the
equipment was not available. Application and usage considerations are summarized
in Table 1.
Impact of Climatic Conditions—
Although only limited :field tests have been conducted, according to the
manufacturer, moderate to heavy rain during or shortly after foam application,
i.e., before the foam can cure, is the only climatic condition that impacts the
use of Topcoat™. Under such conditions, the foam would be washed out. Once the
foam cures, it will be able to shed rainwater and withstand heavy rain events
without significant destruction.
Although requiring further evaluation, other climatic conditions, including
snow, wind, heat and freezing temperatures, are purported not to impact the
application or performance of TopCoat™. Climatic considerations related to the
use of Topcoat™ are summarized in Table 2.
Limited field tests have been performed by the manufacturer. These have
indicated that TopCoat™ can remain as an effective cover an average of 1 to 2 wk
and as long as 3 wk after application. Some shrinkage was observed, but this did
not appear to impact its effectiveness as a cover. (Shrinkage may, however,
impact the foam's effectiveness in shedding rainwater.)
Although an evaluation as to TopCoat™*s effectiveness in meeting specific
critpria established for daily cover has not been performed, some indication of
its effectiveness is available from field tests. No specific observations
regarding vector control were made during these tests, however, if applied in
sufficient thickness to completely cover the wastes, access to animals, bird and
insects would likely be controlled. Field tests also demonstrated that TopCoat™
adheres to the wastes when applied and hence prevents blowing litter. If
properly applied to completely cover the wastes, odors emanating from the working
face would also be controlled. The manufacturer indicated, however, that the
foam itself emits a "wood-like" odor for a short time while curing. Information
concerning potential emissions to the atmosphere during curing was not available.
According to the manufacturer, moisture infiltration also appears to be reduced,
if the foam is properly applied to completely cover the working face. The foam
initially absorbs moisture and subsequently sheds excess rainwater from the
working face. Operational considerations are summarized in Table 2.
Costs associated with the use of TopCoat™ include the cost of foam
' components and application equipment. These costs, based on limited field tests
and use of prototype application equipment, are summarized in Table 4. In
addition, storage facilities for the components and application equipment may
need to be provided, particularly in colder climates.
35
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4.2 SPRAY-ON PRODUCTS
The following slurry and emulsion-based spray-on products were identified
and evaluated; ConCover®, Land-Cover Formula 480, and Posi-Shell1". All of these
products are currently being used as alternative covers at various landfills.
With the exception of Land-Cover Formula 480, site visits were conducted to
observe the use and performance of these products under actual field conditions.
Application, climatic and operational considerations related to the use of these
products are summarized in Tables 5 through 7, respectively. Material and
equipment costs are presented in Table 8.
4.2.1 General Considerations
Common aspects related to application, climatic, and operational
considerations of spray-ons as daily cover are presented in this section.
Considerations specific to a particular product are presented in subsequent
sections.
Application Considerations —
Each of the spray-on products is applied to the working face with a sprayer
applicator which, although specifically designed to apply the particular product,
is similar in design and operation to a hydroseeder. Because these products are
sprayed onto the working face in a relatively thin layer, their effectiveness as
a cover is greatly dependent on the proper application of the slurry/emulsion so
that complete coverage of the wastes is provided. The operator must ensure that
the slurry/emulsion is applied at a uniform thickness and provides a continuous
cover over the waste. This will not only require that the operator uses proper
application techniques, but also that the sprayer be repositioned during
application so that the slurry/emulsion can be applied from different angles to
•cover the "shadows", i.e., uncovered areas that result from applying slurry to
the irregular waste surface from only one direction. If this is not done,
exposed areas of waste will remain which could allow access to vectors, blowing
litter, emission of odors and vapors, and infiltration of rain water.
Working face preparation to provide a well compacted and smooth surface
also has a very significant impact on the time and effort required to apply an
effective cover. If the working face is not properly prepared, a larger total
surface area of exposed wastes will need to be covered, requiring additional time
to apply the cover. In addition, the quantity of material that must be applied
to ensure proper coverage of :the wastes will also be greater, i.e., the less
compacted the working face, the greater the surface area, and the greater the
amount of slurry/emulsion required to properly cover the wastes. This will also
increase the cost of using the product.
Climatic Considerations —
Climatic conditions have a similar impact on the application and
performance of the different spray-on products. These products can be applied
and will form an effective cover under all climatic conditions, except during a
heavy rain event, if such an event occurred either during application or
immediately after application. Only during these periods, before it hardens, can
the slurry/emulsion be diluted and washed out and, hence, not provide a proper
cover. Once the material has hardened, it is able to withstand a heavy rain
event and maintain its integrity.
Temperature extremes are purported to not adversely impact the preparation,
application and performance of spray-ons. According to the manufacturers, these
products have been successfully applied at ambient temperatures ranging from
-20°F (-29°C) to over 100°F (38°C).
Although strong winds may affect application by limiting the distance the
slurry/emulsion can be sprayed, operational adjustments may be made during the
application to compensate for this by either spraying a shorter distance,
36
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repositioning the sprayer or using the hose instead of the spraygun to apply the
nroduct Once applied, the slurry/emulsion adheres to the working face and has
Eeen ob^rvSd towiths'tand winds bf 40 to 50 mph (64 to 80 km/hr).
Operational Considerations—
vector control— The sticky consistency of spray-ons when first applied
discouraoes insect, birds and animals from landing or walking on the working
^cl When hardened, spray-ons form a cover that prevents the emergence of
fnsects and i" difficult for birds and animals to penetrate by pecking or
digging: In addition, birds apparently do not like to land on the material due
to its unfamiliar appearance and texture.
Blowing LittP*- *nd odor Control— When applied to the working face, spray-
ons adhere to the wastes, containing them and preventing blowing litter. When
SardenedTthey farm an effective barrier which controls odors and other emissions
from the working face. Aesthetically, when properly applied, spray-ons provide
an orXrly and sightly appearance that usually blends well with the surrounding
area.
TiMr-e Retardation— Although individual constituents of spray-ons may be
combustible, these materials are mixed with water during P**?*^™™****^
as an aqueous slurry or emulsion. Once applied, they form a barrier that
preveVs^he transfer of atmospheric oxygen to the working face. However, since
?ne lover £f mechanically destroyed by the placement of wastes the"^d°Pf fSs"
day, spray-ons do not provide a lasting barrier to the potential spread of fires
within the landfill.
Minimization of Mois^r-e Infiltration— When applied as a continuous
layer,* and allowed to harden, spray-ons provide a barrier that «"•««*«££
shed rainwater from the working face, thereby limiting moisture infiltration into
the landfill and the resultant generation of leachate.
Dust Control— When applied to the wastes and/or surrounding soils, spray-
ons adhere to these surfaces and prevent blowing dust. In addition, use of
spray-ons eliminates the need to transport and place soil cover, reducing the
generation of dust from that source.
Leachate and Gas Movement— Since spray-ons are f^anically destroyed J°*
the placement ofwastes the following operating day, the freedom of leachate and
gas movement within the landfill is not curtailed.
4.2.2 ConCover®
Concover®, manufactured and distributed by New Waste Concepts, Inc.
(formerly Newastecon, Inc. ) , Perrysburg, OH, consists pf an aqueous slurry which,
when sprayed onto the working face in a 1/8- to 1/4-in. (0.32-to 0.64-c.m)
coSiruoui layer, forms an effective daily cover. This product has been marketed
since 1988, and is currently being used at approximately 20 sites in the United
States and Canada and at several sites in Europe.
ConCovore a polymeric blend of earth-based materials (similar
to that used in food products/cosmetics) and fibrous materials, and Deludes
recycled newspaper and wood fibers (29). A gypsum-based additive called
"lain'lus®" is also available . from the manufacturer. RainPlus® accelerates the
hardening process and is recommended for use when a potential for rain during
appltcatioS exists. The polymeric thickening/binding agent and fibrous Aerials
are provided by the manufacturer in dry form in proportionally-sized bags that
simplify the proper blending of these components. These materials, which do not
reqSreany special storage9 facility or climatic controls, are typically stored
on^site in the trailers used: to deliver the product. When kept dry, these
44
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materials are reported to have an indefinite shelf-life. The components are
mixed with water to create a,pulpy green slurry that is reported to be nontoxic
and biodegradable. *•
Both the blending of ingredients and subsequent application is performed
with a ConCover® All Purpose Sprayer (CAPS). The CAPS, although similar to a
hydroseeder, is specifically designed for the application of the ConCover®
slurry, a much more viscous; mixture. It consists of a storage tank with a
hydrsiulic agitation system, a direct drive pump powered by a diesel engine, a
spraygun with interchangeable nozzles which are mounted on top of the unit, and
a hose reel with 200 ft (61 m) of hose. The unit can also be used for on-site
fire fighting and pressure washing.
The CAPS is available from the manufacturer in various sizes to meet site-
specific requirements (29). These include both trailer-mounted and skid-mounted
(roll-on/roll-of) units which can be placed on a truck bed (Figure 15) . The
capacities of CAPS range from 600 to 3,300 gal (2,270 to 12,490 L). Both the
formulation of ConCover® and certain aspects of the CAPS are patented.
Preparation and Application--
The ConCover® slurry is prepared by batch mixing the dry chemical
constituents with water in the storage tank of the CAPS. A source of soft water,
with a pH between 8 to 10, is required for proper formulation of the slurry. (If
soft water is not available, site operators may need to provide a water softening
unit.) Water is first added to the tank to a predetermined quantity, based on
the size of the area to which the slurry will be applied. (According to the
manufacturer, 100 gal (378 L) of slurry will cover a surface area of
approximately 1,000 ft2 (92 m) with a 1/8-in. (0.32-cm) thick layer. This is
followed by the addition of the proper quantity (one bag per 100 gal (378 L) of
water) of the polymeric binder, referred to as "Bag A". This is then mixed for
approximately 5 min before fibers, referred to as "Bag B", are added to the
mixture (also one bag per 100 gal (378 L)). Following the addition of the
fibers, mixing is continued for at least 20 min.
Preparation of the slurry can be accomplished well in advance of actual
application. (According to the manufacturer, many sites prepare the slurry at
mid-day, so that it is already mixed when it is time to apply daily cover,
thereby saving operator time-.) Once the slurry has been prepared, however, it
should be applied within 48 hr. If the rain additive, RainPlus®,is also used,
it its added to the slurry just prior to application.
At the end of the operating day, the CAPS is towed or driven to the working
face and the slurry is applied using either the spraygun (Figure 16), which is
capable of spraying slurry up to 200 ft (61 m), or the handheld hose, which is
normally used for pin-point application if the area is not accessible to the
spraygun. Different nozzles are provided which can be readily interchanged
during slurry application, depending on the spray pattern desired.
ConCover® is usually applied at a thickness of 1/8- to 1/4—in. (0.32- to
0.64-cm) and adheres readily to waste (Figure 17). Following application,
ConCover® sets in approximately one hour, depending on climatic conditions, to
initially form a flexible barrier which continues to harden and form a durable
crust that can remain as an effective cover material for an average of 7 to 10
(Figure 18) and up to 30 days (CC-l(C-S)).
Although the time required to prepare and apply ConCover® to the working
face will depend on site-specific conditions, e.g., size and compaction of the
working face and the capacity of the CAPS unit used, an average 1 to 1.5 hr would
be required to prepare the slurry and apply it to a 10,000 ft2 (930 m2) working
face (CC-l(C-S), CC-2(C-5)). This assumes that the CAPS was properly sized to
complete the application with one tankful and does not need to be refilled. At
one site, the slurry is reportedly applied to a 6,000 ft (557 m2) working face
45
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Figure 15. Skid-mounted ConCover® Ail-Purpose Sprayer
(CAPS).
Photo courtesy of New Waste Concepts, Inc.
Figure 16. Application of ConCover* slurry onto a
working face using trailer-mounted CAPS.
46
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Figure 17. Close-up view of ConCover® slurry imme-
diately after application of a 1/8- to 1/4-
in. (0.32- to 0.64-cm) thick layer.
Photo courtesy of New Waste Concepts, Inc.
Figure 18. ConCover® 6-7 days after application onto
working face of a hazardous waste landfill.
47
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in approximately 15 min (2). Preparation and application can be performed bv one
operator who prepares the slurry, tows or drivis the CAPS to the T workS, face
and sprays the slurry. According to the manufacturer, many sites ?refe? usina
two operators, one to tow or drive the CAPS to different positions aSund the
working face, and the other to apply the slurry with the spAygun, as this
expedites the application. This is also the case when the hosl is used instead
' operator to contro1 the pump at
°fv, th-S application, water is added to the , empty storage
hosin9' PumP and spraygun (some CAPS are being equipped
tank
«*X «™.i v * ' are eng equipped
with small water tanks for this purpose) . When climatic conditions permit rinse
water may be left in the tank until the preparation of slurry the f olfo^ina dav
"'" W6ather' the tank' P™P ™* hosing are drained and additional
" necessary, are
A3ihou9h special operator skills are not required to prepare and apply
ov, °n-site training is provided by the manufacturer on the pSper
thePCAPS woreove^ fchfn ?* .ConCov.er* ' and the operation and maintenance^
the CAPS. Moreover, the manufacturer is currently modifying the on-site trainina
to a more structured Site Certification Program (30). The primary purpose" Sf
SSiE??""1 ?? n6 t0 deVel°P Snd ^intain operator prof iciency in t^ropSr
application of ConCover® to ensure effective use of the product. The proaraS not
only includes training and evaluation of site personnel, but alsc Tin^orpo^aSs
participation of regulatory personnel with oversight responsibility for the
particular site. This approach is intended to both improve thl ^ requlato?
performance?9 °f thS ^^ 'and tO addr6SS any conc*™s rJgarJing its 2se and
B®?fvlse the Design of CAPS incorporates common components for which parts
feadily availab1*, the manufacturer has not deemed it necessary to pr?vidJ
aPbPl°e Vh°ne ^ USing the °APS indicat*<* that, because parts arl
A v- .^' h® system was operational 99% of the time (CC-l(C-'i))
Application considerations are summarized in Table 5.
Climatic Considerations —
T*- ^anCKnC°Veri®. k,33 ^i1 successfuHy «sed under various climatic conditions.
ivof^ H applitd and f°rm an ef fective cover under all climatic conditions
except during a heavy rain event. Once a crust has formed, usuallv within I hr
of application, ConCover® is able to withstand heavy rains and Tnalntain its
integrity. Temperature extremes do not adversely impact the preparation
application and performance of ConCover®. According to the manufacturer It ha4
been successfully applied at -20°F (-29°C) to 100°F (38°C) Oper'atioSal
adDustments are made during high winds to ensure effective coverage and once
?sS kmX^ ^f6*/. ifc adheres to the wastes and can withstand win^s of 50 mph
SLS22 \ 0 considerations related tcr the use of ConCover® a?e
Performance —
ConCover® has been used as a alternative daily cover at landfills located
throughout . the United states, some of which have used tte product as In
alternative cover for 3 yr. Users have indicated satisfaction with its overall
covfrrmnnCe t^ l*illty.to meet operational and regulatory ^criteria lor la!iy
in SblJ ?P7Sr se^if0"3^6"^0^3 re^ted t0 the USe °f ^ncover® are summarized
tnrtT^f 4.V 4Seve^al independent evaluations on the effectiveness of ConcovPr®
indicate that, when properly applied at a consistent thickness to form a
continuous layer over the working face, ConCover® was an effective alternative
cover which met or exceeded established criteria for daily cover (27, 28^ In
addition, laboratory tests have been performed which demonstrated that Concur®
can effectively minimize infiltration and suppress vapor (tolulne and
tetrachloroethylene) emissions (21). it was also reported by the manulactuiJer
48
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that the cover will discolor when located above "hot spots", hence helping to
pinpoint such areas, and that the slurry has been used to smother a subsurface
fire that coincidentally occurred at a site during an on-site demonstration of
the product.
According to the manufacturer, ConCover® has been approved for use as an
alternative daily cover material in 13 States. Some States allow it to remain
as a cover for up to 7 days. The only other restriction placed on its use is
that it cannot be applied during a .heavy rain event, or if it is likely such an
event will occur before the slurry cures.
Costs—
Costs associated with use of ConCover® include the cost of the dry
chemicals (binder, fibers, and gypsum-based additive used when rain is
anticipated) and the ConCover® All Purpose Sprayer (CAPS). These costs are
summarized in Table 8. Some sites may also require a water softening unit. In
addition, in colder climates, unless the equipment is drained and serviced to
prevent freeze damage after each use, appropriate storage facilities for the CAPS
unit may be required.
Further Research and Development—
Several modifications in the formulation of ConCover® are being evaluated
by the manufacturer. These include using landfill leachate as the aqueous
solution in preparation of the slurry, and alternative binder materials. In
addition, the manufacturer is developing an air-entrained cover material,
ConCover® 180, which purportedly will permit the user to vary the time required
for the cover to harden, improve the cover's durability, and extend the
effective life of the cover. Improvements in operator training and the Site
Certification Program are also being made by the manufacturer to optimize the use
and application of ConCover® as an effective daily cover.
4.2.3 Land-Cover Formula 480
Land-Cover Formula 480, manufactured by Enviro-Group Inc., Indianapolis,
IN, consists of a clay-based emulsion, which when mixed with water and sprayed
onto the working face in a thin 1/16- to 1/8-in. (0.16- to 0.32-cm) layer, dries
to form an effective daily cover. Land-Cover Formula 480 is being used at sites
located in 10 States throughout the United States.
Materials and Equipment—
Land-Cover Formula 480 consists of an emulsion of clay and proprietary
polymers which is reported to be biodegradable and nonflammable. The
concentrate, usually black in color, is provided by the manufacturer in 55-gal
(208-L) drums, and is claimed to have an indefinite shelflife. In colder
climates, the product must be properly stored to prevent freezing.
Land-Cover Formula 480 is mixed with water, usually in a 1:1 ratio, prior
to application as a daily cover. Different dilution ratio's, however, may be
used depending on intended application and use, e.g., desired duration and
permeability, of the cover. A patent is currently pending for this product.
The dilution and mixing of Land-Cover Formula 480 with water and subsequent
application are performed with a specially designed applicator, similar to a
hydroseeder, which consists of a liquid storage tank with agitation system,
engine, centrifugal pump, hose reel with 50 to 100 ft (15.3 to 30.5 m) of hose,
and handheld spraygun with adjustable nozzle. A 15-ft (4.6-m) spraybar with
several nozzles, which can be mbunted behind the unit to apply the mixture as the
unit is towed or driven across the working face, is also available.
Different sizes of the applicator unit are available from the manufacturer
to meet site-specific requirements (5), with storage tank capacities ranging from
200 to 1,000 gal (757 to 3,758 L). The units are skid-mounted and can be placed
49
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on a trailer, which is also available from the manufacturer, or in a truck bed.
As with other spray-on products, this product can also be used for intermediate
cover and erosion or dust control.
Preparation and Application—
Land-Cover Formula 480 is prepared by batch mixing the emulsion with water
in the storage tank of the application unit at the appropriate dilution ratio
based on the intended application, e.g., daily or intermediate cover. The
emulsion can be transferred from the barrels into the storage tank by using the
liquid transfer pump provided with the application unit. Water can be similarly
added from a tank truck or other source if a pressurized source is not available.
According to the manufacturer, approximately one gallon of solution is required
to cover 80 to 100 ft (7.4 to 9.3 m ) of working face, i.e., one 55-gal (208-L)
drum diluted at a 1:1 ratio should be adequate for a 10,000-ft2 (930- m2) working
face. This claim has been substantiated by the manager at a site using this
product (LC-l(C-6)). Hence, coverage per tankful can range from 16,000 ft
(1,486 m2) for a unit with a 200-gal (757-L) tank up to 100,000 ft2 (9,300 m for
a unit with a 1,000-gal (3,705-L) tank. Although preparation time will vary
according to site-specific conditions, such as the quantity of mixture required,
it will typically range from 30 to 45 min.
Preparation of the emulsion and water mixture can be accomplished well in
advance of application, and any unused mixture can be left in the tank for
several, days. To apply Land-Cover Formula 480, the application unit is towed,
or driven if truck-mounted, to the working face at the end of the operating day,
and the: mixture is applied using either the handheld spraygun or the spraybar.
If applied with a spraygun, which has a range of 100 to 150 ft (30.5 to 45.8 m),
the mixture is usually sprayed from a position on top of the trailer or truck.
For areas that are difficult to reach, pinpoint application can be accomplished
by walking to those areas, unrolling hose as necessary. Alternatively, for
appliccition units equipped with a spraybar mounted at the rear of the unit, the
mixture can be applied by towing the unit across the working face with a dozer
or other landfill equipment. The handheld spraygun can be used in conjunction
with the spraybar to touch up any areas that cannot be sufficiently covered in
this manner.
The mixture is applied at a thickness of 1/16- to 1/8-in. (0.16- to 0.32-
cm) and readily adheres to the wastes. The manufacturer has indicated that the
application time for a 10,000-ft2 (930 m ) working face averages 1 hr. One site
reportedly applied Land-Cover Formula 480 to a 10,000- to 15,000-ft (930- to
1395-m2) working face in 30 to 45 min (LC-l(C-6)). Following application, the
mixture dries to form a flexible layer within 15 to 45 min, depending on
temperciture and humidity.
Although the preparation and application of Land-Cover Formula 480 can be
done by one operator, sites typically use two operators for the application; one
to tow or drive the application unit, and the other to apply the mixture to the
working face. Subsequent to application, the manufacturer recommends that the
unit's storage tank, pump and hoses be rinsed with water to prevent any buildup
of residual, a procedure that requires 10 to 15 min to perform. In colder
climates, appropriate measures, e.g., draining hoses and pumps or providing
inside storage, need to be taken to prevent possible damage to the equipment
during freezing conditions.
No unique operator skills are required to prepare or apply this product.
Training and assistance in proper preparation and application procedures are
provided by the manufacturer. The application unit incorporates common
components for which repair parts are readily available, and very little down
time has been experienced with the application unit (LC-l(C-6)). Application
considerations are summarized in Table 5.
50
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Climatic Considerations—
Land-Cover Formula 480 has been successfully used under various climatic
conditions throughout the United States. As with other spray-ons, Formula 480
can be applied and will form an effective cover under all climatic conditions
except a heavy rain event. Once the emulsion has dried, usually within 15 to 45
min, it can withstand heavy rains. According to the manufacturer, the product has
been successfully used throughout the winter in Northcentral States with
temperatures as low as -20°F (-29°C). No preparation or application problems were
encountered at a site in Florida during hot weather at temperatures of 90°F to
95°F {32° to 35°C) (LC-l(C-6)). Climatic considerations related to the use of
Land—Cover Formula 480 are summarized in Table 6.
Performance—
As previously indicated, Land-Cover Formula 480 has been used as an
alternative daily cover at landfills throughout the United States, with some
sites using the product for several years. According to the manufacturer, this
product was initially developed in 1986, at which time a 3-yr field trial was
conducted to evaluate its overall effectiveness as a cover material as well as
its potential long-term impacts on landfill operation and management. The
results of the field trial demonstrated that the product was able to provide an
effective daily cover under various climatic conditions without interfering with
landfill operations or the composition of leachates (LC-M (C-6)).
According to the manufacturer. Formula 480 can remain an effective cover
for up to several months, depending on the thickness of cover, e.g., dilution of
concentrate and number of coats applied, and climatic conditions. The operator
of a site using the product at a 2:1 dilution (water to concentrate) for
application as an intermediate cover indicated an average effective life of 35
days (LC-l(C-6)). A "touch-up" layer can also be applied to extend the duration
of a cover.
The dilution ratio used in preparation of the mixture affects the
permeability as well as durability of the cover material, and thereby also
impacts its ability to minimize water infiltration. Laboratory permeability
tests conducted at different dilution ratio's indicated that at a 1:1 (water to
concentrate) ratio, an impermeable cover was formed, while at a 3:1 ratio, a more
permeable cover was formed (;5). Test results did not report the actual
permeability at this latter dilution. The manufacturer has indicated that this
flexibility in water:concentrate ratio allows the site to select a cover of
appropriate permeability (and durability) to meet its specific needs. Typically,
sites using Land-Cover Formula 480 as a daily or intermediate cover apply the
product at a dilution ratio which permits formation of a relatively impermeable
cover that can effectively shed rain water during moderate and heavy rain events.
Operational considerations related to the use of Land-Cover Formula 480 are
summarized in Table 7.
Land-Cover Formula 480 has been approved for use in 10 States throughout
the United states. The manufacturer has indicated that State regulatory approval
for using the product within the State is sought prior to marketing the product
at individual sites. Although a field demonstration at a site within the State
is usually required to obtain approval, this approach facilitates the subsequent
approval for the use of the product at other sites within the State, i.e., other
sites may not need to conduct additional demonstrations. This approach was
successfully used in Florida to obtain State-wide approval for the use of Land-
Cover Formula 480 as an "initial" cover material, which, in Florida, can be used
to cover wastes in landfill areas that will subsequently be covered with
additional wastes within 3 to 6 mo (5).
Costs—
Costs associated with the use of Land-Cover Formula 480 include the cost
of the concentrate and application unit (with trailer, if required). These costs
are summarized in Table 8. According to the manufacturer, costs are dependent
on the product dilution ratio, number of coats applied, and smoothness of the
51
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working face. In colder climates, storage facilities to protect the concentrate,
and possibly the application unit, will also be required.
4.3.4 Posi-Shell".
Posi-Shell"* synthetic cover system, developed and marketed by Landfill
Services Corporation, Apalachin, NY, consists of an aqueous slurry of fibers and
a binding agent, sprayed onto the working face in a 1/4- to 1/2-in. (0.64- to
1.27-cm) thick layer. Following application, the formulation stiffens to a
stucco-like consistency to form an effective cover material. This product is
currently being used at several landfills located in New York State.
Materials and Equipment—
Materials used in preparation of the slurry include cellulose and plastic
fibers from recycled paper or plastics, a mineral binder (cement kiln dust), and
water. The mixture of fiberous materials is provided by the manufacturer in 50-
Ib (22.7 kg) bales called Posi-Pakws. These bales are stored on-site and do not
require any special storage facility or climatic control. Cement kiln dust, the
binding agent, is typically procured from a locally available source, delivered
by pneumatic tanker truck and stored on-site in a silo specially designed to
facilitate the transfer of cement kiln dust into the mobile sprayer unit.
According to the manufacturer, none of these materials are considered hazardous.
Although cement kiln dust has been known to contain trace quantities of various
metals, the manufacturer has indicated that TCLP extractions conducted on samples
of the cement kiln dust being used have shown these levels to be below detectible
limits (PS-M(C-7)). A patent has been granted for this synthetic cover system.
Both the preparation of the slurry and its subsequent application to the
working face are performed by a specially designed mobile sprayer (Figure 19),
which functions similar to a hydroseeder. This relatively simple unit primarily
consists of an engine, 1,200-gal (4,540-L) storage tank with agitator, high
pressure pump, spraygun, and hose reel with 100 ft (30.5 m) of hose. This system
is also multi-functional; when not being used to apply slurry, the sprayer can
be used for dust and fire control.
Preparation and Application—
The slurry's constituents, fibers, a binding agent and water, are batch-
mixed in proper proportions (the actual proportions are considered proprietary
by the manufacturer) in the storage tank of the mobile sprayer. Approximately
15 min is required for the preparation of the slurry. The mobile sprayer,
although specially designed to permit access to steep slopes and muddy areas, is
not self-propelled. Hence, although capable of traversing all areas of the
landfill, it must be towed, usually by a dozer.
The slurry is typically sprayed onto the waste using a rotating spraygun,
or turret, mounted on top of the mobile sprayer (Figure 20). Different nozzles
are provided which can be readily interchanged during slurry application,
depending on the spray pattern desired. The pump provides sufficient pressure
to permit the slurry to be sprayed over 100 ft (30.5 m). A handheld hose,
mounted on a hose reel, can also be used for application of the slurry in areas
not accessible to the spraygun.
The slurry is applied at a thickness of 1/4 to 1/2 in. (0.64 to 1.28 cm),
and adheres to the wastes to ;effectively control vectors, blowing litter and
odors immediately upon application (Figure 21). Following application, the
slurry stiffens to a stucco-like appearance within 1 to 2 hr, and completely
hardens overnight.
to 6
The application unit has the ability to cover an area ranging from 2,000
,OOO ft (186 to 557 m2) per 1,000-gal (3,785-L) tankload in 20 to 30 min,
depending on the desired thickness of the cover and smoothness of the working
face (PS-l(C-7)). A 1/4-in (0.64-cm) thick layer of Posi-Shell™ is considered
sufficient to provide an effective "overnight" cover while a 1/2-in. (1.29-cm)
52
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Figure 19. Posi-Shell™ mobile sprayer (early model)
Figure 20.
Application of Posi-Shell™ slurry with
spraygun mounted on mobile sprayer.
53
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Figure 21. Close-up view of Posi-Shell1" slurry
immediately after application of a 1/4- to
1/2-in. (0.64- to 1.27-cm) thick layer.
thick layer is usually applied if the area may not receive additional wastes for
several weeks. For a larger working face, additional tankloads of slurry will
f PrePar?d- Depending on the proximity of the preparation area to the
»™" »fC% ^S fan r.e<5uire an additional 15 to 30 min per tankload to
accomplish. Application is usually performed by one operator who prepares the
workin' face sPrayer to the working face, and sprays the slurry onto the
Upon completion of applying the slurry to the working face, water is added
to the empty storage tank to rinse the tank, pump, hosing and spraygun, typically
a 10 to 15-min procedure. When climatic conditions permit, efg, above freezing
temperatures, the rinse water is left in the tank for preparation of the slurr?
the next operating day. In freezing weather, the tanks and hosing are drained
„« ?«eJJf ^•af-agS ?°™h*Se comP°nents «nder such conditions. This may require
«?„ V? add,xt^onal 3? min to Perform. Alternatively, the mobile sprayer -CM be
stored inside during freezing weather conditions as with other spray-on products.
uni'que. operator skills are required to prepare and apply this cover
h ii« ite trai.nin of Personnel in the preparation and application of
-Shell™ and application equipment maintenance is provided by the
manufacturer. Once operator proficiency is attained, usually within a week,
™o^LPriep,arati°n'*application and equipment cleanup typically requires an
operator 1 hr to perform. Application considerations are summarized in Table 5.
Climatic Considerations—
The only purported adverse climatic effect on the use of Posi-Shell"- is a
heavy rain during or immediately after application of the slurry, which could
hr thf B H SJUrry b^rS ^ hardens' Once ifc stiffens, usually7within 1 to 2
hr, the product can withstand heavy rains, and it has been successfully applied
54
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during all other climatic conditions including freezing and hot weather, high
winds and snow. Climatic consideration related to the use of this product are
summarized in Table 6.
Performance—
The Posi-Shell™ cover system has been used as a daily cover material on a
continuous basis since September 1990 at two sites in New York State. During
this period, there have been only 10 to 15 days- when it was not used due to heavy
rainfalls at the time of application (PS-l(C-7)).
Posi-Shell™ has been demonstrated to remain effective as a daily cover,
without significant deterioration and under all climatic conditions, for periods
of time ranging from a week (Figure 22) to several months (PS-l(C-7)). The only
deterioration noted was development of hairline cracks on the surface of the
cover, similar to that which would occur with hardened cement. The manufacturer
indicated that there are areas where Posi-Shell™ has been used as an intermediate
cover, including steep side slopes, for periods exceeding six months by
periodically applying a thin "touchup" layer of slurry.
When properly applied, Posi-Shell™ meets operational and regulatory
• criteria for daily cover. Operational considerations related to the use of Po«=ii-
Shell"1 are summarized in Table 7. Once Posi-Shell™ hardens, it forms a stucco-
like crust which is difficult for birds and animals to penetrate. The cover is
also nonflammable. (The manufacturer has demonstrated that the hardened cover
will not burn even when exposed to the flame of an acetylene torch.) Its ability
to control odors has also been partially attributed to the presence of lime in
the cement kiln dust. At one location where wastes are disposed of within 500
ft (153 m) of a residential area, and Posi-Shell™ is used as a cover material,
there have been no complaints regarding odors (PS-l(C-7)). The manufacturer is
also experimenting with the addition of fragrances to the slurry to further
augment odor control. The reduction in the generation of dust with the use of
the cover product was reported to be of particular importance at one site, since
the available cover material was a fine sand and the site was located close to
a residential area (PS-l(C-7)). Furthermore, Posi-Shell™ has been found to be
easier to apply than soil, as problems encountered with placement of soils during
rainy conditions and the excavation and placement of frozen soils during winter
freezing conditions were eliminated.
Posi-Shell™ was used at one site as part of a New York State Solid Waste
Management Facility Research, Development and Demonstration Project. The goal
of this project was to demonstrate equivalency of Posi-Shell™ to soil as a daily
cover (PS-M(C-7)). According to the manufacturer, the demonstration project has
been satisfactorily completed and State regulatory approval for the use of this
material at landfills in New York State has been received.
Costs—
The costs associated with the use of Posi-Shell™ as a daily cover material
include material costs and the cost of leasing the application equipment and
storage silo. (The manufacturer only leases the equipment, which includes
license to use their patented technology.) These costs are summarized in Table
8. Material costs may vary based on local availability of the fibers and binding
agent (cement kiln dust). In addition, although during freezing weather the
application equipment is usually drained and serviced after each use to permit
outside storage, some sites may prefer to use indoor storage facilities during
such conditions.
Further Research and Development—
Several areas for improving and modifying the use of Posi-Shell™ are being
investigated by the manufacturer, and include the use of leachate as the aqueous
solution for preparing the slurry and alternative materials as the binder.
Initial indications are that leachate can be used as an aqueous solution 1-0
prepare the slurry. The cement kiln dust binder material, with its lime content,
is effective in neutralizing the leachate pH and odor. The use of fly ash as an
55
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Figure 22. Close-up view of Posi-Shell™ 8-10 days
after application of a 1/2-in. (1.27-cm)
thick layer.
alternative binder is also being investigated, since this material may be more
readily available-than cement kiln dust.
4.3 GEOSYNTHETIC PRODUCTS
The following geosynthetic products were identified and evaluated for.their
feasibility as ADCMs; Airspace Saver™ Daily Cover, Aqua-Shed™, COVERTECH C-440,
CORMIER, FabriSoil®, Griffolyn®, Polyfelt, SaniCover™, and Typar®. All of these
products are currently being used as alternative cover materials at various
landfills. Selected site visits were conducted to observe the use and
performance of some of these products under actual field conditions. Emphasis
was placed on observing methods used to place and retrieve the various
geosynthetic panels. Preparation and application, climatic, and operational
considerations related to the use of these products are summarized in Tables 9A
through 9C, 10A through IOC, and 11A and 11B, respectively. Material and
equipment costs are presented in Tables 12A through 12C.
4.3.1 General Considerations
Common aspects of panel placement and retrieval, and climatic and
operational considerations related to the use of these materials as daily cover
are summarized below. Procedures and considerations specific to the use of a
particular product are presented in subsequent sections as appropriate.
Placement and Retrieval— ;
Size of Working face— The size of the working face must be carefully
managed throughout the operating day and restricted to predetermined dimensions
so that it can be completely covered by the panel. If the size is not properly
56
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Comments
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managed, either additional panels would need to be placed, or soil cover would
have to be made available at the working face and placed onto areas that remain
exposed, after placement of the panel. This use of soil cover would not only
require additional time and labor, but would also consume landfill capacity.
Working Face Preparation— The preparation of the working face prior to
placement of the panel and the care taken in placement of the panel can have a
significant impacts on the effective life of a panel. Consequently, operators
should ensure that the working face is properly compacted to provide a smooth
surface, and that protruding objects which could damage panels are eliminated.
In addition, during placement ,of panels, measures should be taken to prevent
unnecessary stress on the material and minimize snagging while dragging the panel
across the working face.
Panel Placement— Most geosynthetic cover materials are placed onto the
working face either manually or using landfill equipment, such as compactors or
dozers^ although specially designed and fabricated equipment is used at some
sites.
Manual placement is usually restricted to placement of light-weight and/or
small panels which can be deployed by lifting or dragging the panel with a two-
to three-person crew. However, placement of panels in this manner often will
requires crews to walk across the working face while dragging the panel, a
procedure that increases both risk of injury and exposure to the waste.
To place panels using landfill equipment, both corners of the leading edge
of the panel are typically attached to the blades of the equipment using chains,
ropes, or nylon straps. The corners are attached as high on the blades as
possible, and the blades are lifted during placement to reduce drag as the panel
is towed across the working face. By wrapping a smooth round object (e.g.,
discarded ball or smooth rock) in the corner of the fabric, securing the strap
around it, and then attaching the strap to the equipment instead of puncturing
the panel to attach the strap, a more durable connection that is less prone to
tearing can be provided. Alternatively, some sites use a steel bar or rod
inserted into pockets sewn along the leading edge to reduce localized stress on
the panel. This bar or rod is then attached to landfill equipment to facilitate
dragging of the panel across the working face. Once placed, a ground crew
normally assists in making final adjustments to the panel to ensure that the
working face is completely covered, and to place anchoring to secure the panel
over the wastes.
At some sites, specially designed and fabricated equipment, e.g., rollers,
lifting bar, or hydraulic reel, is used to facilitate the placement of panels and
extend their effective life. When using rollers, panels are attached to a 25-
to 30-ft (7.6- to 9.1-m) roller, usually fabricated from sections of conduit,
which can then be placed onto a custom-fabricated skid. The skid is dragged to
the edge of the working face by landfill equipment, where the roller is detached
from the skid and the panel unrolled down the working face. Use of rollers has
been demonstrated to not only extend the effective life of panels, but also to
reduce difficulties encountered in panel placement during windy weather
conditions. The use of a lifting bar and hydraulic reel, currently used to place
specific geosynthetic products, is discussed in subsequent sections.
Anchoring— Panels are routinely anchored after placement to prevent them
from being blown off the working face and exposing the wastes. Typically,
discarded tires or sandbags, which can be stockpiled near the working face, are
placed along the edges and across the panel at intervals ranging from 20 to 30
ft (6.1 to 9.1 m), depending both on the weight of the material and anticipated
wind conditions. Some sites, prefer to place soil on the edges as a more
effective and efficient method for securing the panel, particularly if soil is
routinely used to cover any exposed areas of wastes remaining along the edges of
the panel after placement.
73
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Panel Retrieval— Panels are normally removed from the working face prior
to the start of the next operating day. Hence, the necessary personnel and
equipment have to be available, and sufficient time must be allowed, for this
activity to be performed prior to the arrival and disposal of waste at the
working face. This may require modification of the work schedule for site
personnel. Furthermore, depending on the season of the year and operating hours
at the site, panel retrieval may have to be performed while it is still dark,
thereby increasing the risk of accidents or injury.
Retrieval is accomplished by reversal of the procedures used to place
panels. Anchoring materials are first removed and stockpiled near the working
face. If soil was used to secure the edges, particular care must be taken not
to tear the panel upon retrieval. Panels are then removed, either manually or
using landfill equipment, by pulling them back over themselves to minimize
snagging. They are then stored near the working face for subsequent use. If
skid-mounted rollers were used, the panel is rolled back to the skid which is
then dragged to an area adjacent to the working face.
Panel Disposal— Panels are typically reused until they are no longer able
to serve as effective daily cover due to physical deterioration of the material,
tearing and punctures during placement and retrieval, and climatic stresses
imposed by rain, wind and freezing temperatures. Such panels are either disposed
of within the landfill or used for other purposes at the site. Disposal within
the landfill is reportedly accomplished by either tearing and shredding the panel
with landfill equipment while the panel is still in place, or by retrieving,
folding, and then burying along with other waste. Such disposal practices,
however, may result in subsequent operational problems, as the buried panels
create barriers which can impede the controlled movement of leachates and gases
within the landfill. Alternatively, panels that are no longer useful as daily
cover have reportedly been used for reinforcing roadbeds, lining drainage
channels, and controlling erosion of side slopes.
Climatic Considerations—
Rain— The impact of rain varies with the composition of the particular
geosynthetic material. Although the use of geosynthetic products need not
necessarily be restricted during rain events, nonwoven materials can absorb
moisture and become heavier and more difficult to handle. Water repellant
materials are not affected by rain events.
Wind— The impact of wind on the placement of panels onto the working face
is primarily dependent upon the weight of the material and size of the panel.
For example, a large, light-weight panel will be more difficult to place under
windy conditions than a smaller and/or heavier panel. The method used to place
a panel, whether manually, towed with landfill equipment or rolled onto the
working face, also influences the potential impact of wind during placement.
Specific impacts of wind on placement of the various products are presented in
the following sections. The impact of wind subsequent to placement, such as
panels being blown off the working face, is primarily dependent upon proper
anchoring of the panels. When properly anchored, panels have been reported to
withstand winds of 50 mph (80 km/hr).
Freezing Temperatures— Although freezing temperatures alone do not
restrict the use of geosynthetics, if the panel has absorbed moisture, as can
occur with nonwoven materials, it can freeze and adhere to portions of the
underlying waste if placed onto the working face prior to freezing conditions.
Similarly, the panel can freeze onto itself or the underlying soil if freezing
conditions develop while the panel is stored. Under such conditions, the
retrieval or placement of the panel will be more difficult and time-consuming and
will increase the likelihood of damage to the panel. The impact of freezing
conditions on geosynthetic materials that are water repellant and do not absorb
moisture is less significant. However, moisture trapped between the working face
and a panel can, on occasion, cause it to freeze to portions of the underlying
74
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durlna fra^ncT f-** removal more difficult. Panels also become slippery
!™?;Lf 4- ,9,. conditlons< and extra caution must be used when crews are
required to walk on the panels during placement or retrieval of anchoring.
a-- in order to prevent damage or possible loss, geosynthetic
^? .rs. ~
. -4,-. Ti^n/
retrieval without removal of snow also increase thl likelihood of tearlna and
destroyxng the panel due to the additional weight imparted by the snow! with f
heavy snowfall, removal of snow may be impractical. This can result in the loss
P or necessitate the use of an alternative working face until thl snow
aiValternat:LVe,, working face is not available, the buried panel may
Operational Considerations—
%£^S^-J^£?tt* P^d-°ver the^working face, geosynthetic
may s
«
particularly if constructed of light-weight material. P^operxy anchored,
faf. Blowi"5 Lf^ter and od°r Control— As long as the dimensions of the workina
face are controlled so that the panel (s) will completely cover the workina £ ace
titt^ ter " effectively Controlled. Aesthetically, several user? nSSd
that these cover systems looked better and provided a more sightly ajjearance
than BOO.! cover, S1nce there are fewer objects protruding from the working facl?
o^^he
on c°nducted, by RUSMAR, Inc. (22) , geosynthetics can provide tffecive
control of odors and other emissions, although the effectiveness varies
different products. Results indicated that Airspace Saver™ and ' Griff oSn
as effective as foam in the control of odor (99% or greater), while the odor
control efficiency provided by FabriSoil® was 82%, baled on samples collected
both immediately after placement and the following morning dThr later) Is
with the foam, methane control efficiencies of 100% were also reportld lor all
three products immediately after placement, but these decreased P '
specific organic compounds were not performed on these saples.
while h ,re9ardl.ess ,°f the control of odor and other emissions provided
while the panels are in place on the working face, upon retrieval of t>ane\a
particularly when the panels had been left in place for several ^ days, thSre iln
«LairS ?n* °-f °d.°r.S °r °ther emissions that were previously contained^ by thS
panel (This is similar to what can occur when soil daily cover is scraned fl-om
a working face prior to the start of the next operating day ° as is JJacticed 5?
some sites to conserve landfill capacity and soil.) is practiced at
and 8elf-eJSn^laBMnir" Alth^ugh some geosynthetics are rated as nonflammable
ana sej.f extinguishing, or are available with a f ire-ret ardant finish e cr
AStoleuSt?b?.C°^IER' materf als currently being used as alternative daA'y cov^r
are combustible. However, moisture absorbed by nonwoven materials during use can
75
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1
reduce •their combustibility. Also, the placement of panels onto the working face
can reduce the transfer of atmospheric oxygen to the wastes, the effectiveness
of which is dependent on the permeability of the particular material. Moreover,
since panels are typically removed prior to placement of wastes during the next
operation day, they do not provide a fire barrier within the landfill.
Minimization of Moisture Infiltration— Many geosynthetic materials are
water-resistant and, when properly placed onto the working face without gaps
between panels if multiple panels are used, effectively shed rainwater, prevent
infiltration into the wastes, and thereby help to reduce the generation of
leachate. Although nonwoven materials initially absorb moisture during rain
events, similar to soil cover, they are also able to subsequently shed water from
the working face, depending on the intensity of the rain event. Furthermore,
moisture absorbed by these materials can evaporate without infiltration into the
landfill.
Leachate and Gas Movement— Since panels are removed before the start of
the next operating day, leachate and gas movement within the landfill is not
curtailed, as no restrictive barriers remain within the landfill.
4.3.2 Airspace Saver" and COVERTECH C-440.
Airspace Saver™ Daily Cover, manufactured by Wire Rope Specialist, Baton
Rouge, LA, and COVERTECH C-440, manufactured by COVERTECH Fabricating, Inc..,
Rexale, Ontario, Canada, are very similar cover materials as both manufacturers
use the same fabric, FABRENE®, and incorporate a nylon web strapping system which
supports the fabric (13, 50). Both systems are also designed for long-term use
(12 to 18 mo) as daily covers. Airspace Saver™ has been used at sites in 13
States, principally in the Southeastern United States, and has been available
since 1989. COVERTECH C-440 has been used at several sites in the United States
and Canada and has been available since 1990. Because of the similarities in
fabrication, use, and performance, both of these cover systems will be presented
together in this section.
Material— ,
These alternative daily cover systems both consist of a woven fabric of
high—density polyethylene tapes, i.e., threads, coated on both sides with a low-
density polyethylene. Panels are fabricated by heat welding sections of fabric
together, and then reinforcing the fabric by sewing high tensile strength nylon
web straps over the heat welds (which are at 12-ft (3.7-m) intervals), at right
angles to the heat welds (also at 12-ft (3.7-m) "intervals), as well as along the
edges of the panel (13, 50). Steel "D" rings are attached to the ends of the
straps to facilitate lifting or dragging of the panel as it is placed or removed
from the working face. According to the manufacturer, COVERTECH C-440 differs
from Airspace Saver™ Daily Cover by using strapping on both sides of the fabric,
and different fabrication and sewing techniques to attach the strapping system
to the fabric.
These cover systems are unique among the various other geosynthetic cover
systems currently available, since a strapping system has been incorporated into
the design to decrease stress on the fabric and increase the panel's longevity.
(Wire Rope Specialists has indicated that a patent is pending for their Airspace
Saver™* Strapping System. (50)) The fabric, which weighs 9.0 oz/yd (305 g/m2),
without strapping, is also very durable and water resistant.
Although also available in various customized sizes, the standard size
panel is 48 by 50 ft (14.6 by 15.3 m) and can cover an area of 2,400 ft2 (223 m2}.
This size has been determined to be the most practical for handling by landfill
personnel and equipment. Typically, several of these panels are used to covesr
a working face.
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Placement and Retrieval of Panels—
These panels are usually deployed by lifting or dragging the panel, either
manually or with landfill equipment (compactors or dozers), onto the working
face- When multiple panels are used, as is typically the case for these cover
systems, individual panels are sequentially placed and overlapped approximately
2 to 3 ft (O.6 to 0.9 m) until the entire working face is covered. A crew of two
to three (minimum of two) can manually place a single 48 by 50 ft (14.6 by 15..3
m) panel within 5 to 10 min (AS-l(C-8)). Landfill equipment is usually used for
larger-sized panels. Placement of panels to cover a 100 by 100 ft (30.5 by 30.5
m) working face using such equipment averages 20 to 30 min.
Alternative Methods of Placement— Other innovative methods for placement
of these panels, using either a custom-designed lifting bar in conjunction with
a trackhoe excavator or a skid-mounted roller, are reportedly being used at
several landfills (AS-l(C-S), AS-2(C-8), CT-l(C-ll)).
At sites using the custom-designed lifting bar in conjunction with a
trackhoe excavator, a 50-ft (15.3-m) spreader bar with hooks spaced at 12-ft
(3.7-m) intervals, which align with the strapping system, is attached to the
trackhoe's bucket. The bar is placed perpendicular to the lifting arm and
attached with retaining pins to the bucket - a five-minute procedure. Next, the
"D" rings along the edges of opposite ends of a panel are simultaneously attached
to the spreader bar. Several panels can be attached to the lifting bar in this
manner. The trackhoe then lifts the bar and panels until they have cleared the
ground and are hanging vertically from the lifting bar (Figure 23), and
transports them to the working face. Once the trackhoe has maneuvered to the
correct position at the working face, the lifting bar is lowered (Figure 24), one
edge of a panel is detached, the trackhoe extends the section by backing up, and
when fully extended, ,the other edge of the panel is detached and placed onto the
working face (Figure 25). This procedure is repeated to place additional panels
as may be required to cover the working face. Using this method, a trackhoe
operator, assisted by a two-person ground crew which guides the operator, unhooks
the panels, and makes final adjustments once the panels are placed onto the
working face, can cover a 10,000 ft (930 m) working face (Figure 26) in less
than 3O min (AS-2(C-8)). One user reported placing 12, 48 by 50 ft (14.6 by 15,3
m) Airspace Saver™ panels in 1 to 1.25 hr (AS-l(C-8)).
Coordination between the equipment operator and ground crew is necessary
to efficiently use this procedure and minimize risks of accidents, since it
requiress that personnel walk on the working face in close proximity to the
spreader bar while it is being moved. This method can also be used without a
ground crew, but would require more time since the operator would have to
dismount the trackhoe to unhook and adjust each of the panels. By using this
method to lift, transport, and place the panels onto the working face, wear and
tear on the panel that would otherwise occur if they were dragged onto and off
the working face are greatly reduced, thereby extending the useful life of the
panels.,
Another site reported using a skid-mounted roller to place 25 by 50 ft (7,.6
by 15.3 m) COVERTECH C-440 panels (CT-1(C-ll)). Using this method, panels are
attached and rolled onto a 25-ft (7.6-m) roller which is then placed on a custorn-
fabricated skid to tow the roller to and from the working face, placing and
retrieving the panel(s) as previously discussed. It usually requires a two-man
crew approximately 30 min to cover a 50 by 50 ft (15.3 by 15.3 m) working face
using two skid-mounted rollers, including both the placement and anchoring of the
panels..
Anchoring of Panels— Once panels are placed, regardless of the method
used, they are typically anchored by placing sand bags or tires on the edges at
15- to 20-ft (4.6- to 6.1-m) intervals. It will usually require a two- to three-
person crew approximately 15 to 20 min to place anchoring onto a 100 by 100 i:t
(30.5 by 30.5 m) working face (AS-l(C-S)). Because of the additional time and
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Figure 23. Lifting bar, attached to excavator bucket,
being used to place 48 by 50 ft (14.6 by
15.3 m) Airspace Saver™ panel. (Can also be
used to place COVERTECH C-440 panels.)
Figure 24. Leading edge of panel being lowered onto
working face by excavator equipped with
lifting bar.
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Figure 25. Trailing edge of panel being detached from
lifting bar after extension over working
face.
Figure 26. A 10,00 ft2 (930m2) working face covered
with panels placed using lifting bar.
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personnel required, anchoring is used at some sites only if winds in excess of
20 mph {[32 km/hr) are expected. :
To eliminate the need to anchor panels once they are placed onto the
working face, some sites have modified the fabrication of panels by adding a 5/8-
in. (l.<5-cm) chain in the seam around the entire edge of the panel ;(AS-l(C-8),
AS-2(C-8)). This modification has been demonstrated to be effective in anchoring
the edges of panels and preventing them from being blown off the working face at
winds of 35 mph (56 km/hr). The additional weight of the panels, due to the
addition of the chain, does not significantly affect handling of the panels.
Retrieval— Retrieval of the panels, whether placed manually, with
landfill equipment, or with a skid-mounted roller, is accomplished by reversal
of the procedures used to place the panel. If the trackhoe with lifting bar is
used, the trackhoe maneuvers the spreader bar to permit- attachment of the "D"
rings on one edge of a panel, lifts and draws the panel back, and lowers the bar
again to permit attachment of the "D" rings on the opposite edge of the panel.
This procedure is repeated with the other panels. Once all panels are removed,
the trackhoe maneuvers to a storage area near the working face and lowers the
lifting bar (with panels still attached). The bar is then detached from the
trackhoe's bucket, making the trackhoe available to perform other functions
during the operating day. If the skid-mounted roller is used, the panel is
reattached to the roller, rolled back to the skid and then attached. The skid
is then . towed to an area adjacent to the working face. Application
considerations are summarized in Tables 9A and 9B for Airspace Saver1" and
COVERTECH C-440, respectively.
Climatic Considerations—
Climatic conditions that may impact the use of these cover systems are snow
or windy conditions. The significance of any potential impacts due to snow or
wind are also dependent upon the size of the panels and method of placement used.
Although normally not used when snow is predicted, for reasons previously
presented, because of the thickness and durability of the fabric, there appears
to be less risk of puncturing ,or tearing this fabric (as compared to thinner
materials) if snow is to be manually removed. Nonetheless, snow removal would
still be a time-consuming and labor-intensive task. A site that uses a lifting
bar and trackhoe to place and retrieve panels reported that with a 2- to 3-in.
(5— to 7.6—cm) snowfall, snow was removed by attaching the spreader bar to one
end of a 48 by 50 ft (14.6 by 15.3 m) panel and gradually lifting the panel to
allow the snow to slide off the panels, thereby eliminating the need to manually
remove the snow (AS-2(C-8)).
Because of the heavier 9 oz/yd2 (305 g/m2) weight and smaller 48 by 50 ft
(14.6 by 15.3 m) size of panels typically used, wind does not impact the
placement of these products as much as similar conditions may affect other cover
systems consisting of larger, lighter-weight panels. These panels have been
placed manually, with landfill equipment, and by using a trackhoe with lifting
bar, at winds of 20 mph (32 km/hr) (AS-l(C-S)).
Neither rain nor freezing conditions were reported to adversely impact the
use of these cover systems. Since the.material is water-resistant, rainwater is
shed and not adsorbed by the material. Cold or freezing weather was also
reported not to noticeably affect the flexibility of the material or inhibit its
placement and removal under such conditions. Climatic considerations related to
the use of these products are summarized in Tables 10A and 10B for Airspace
Saver1" and COVERTECH C-440, respectively.
Performance—
Based on user experience, the overall performance of both these cover
systems as alternative daily cover has been very satisfactory. Users expressed
particular satisfaction with the panel durability, which permitted continuous use
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under various climatic conditions for long periods of time. One site located in
South Carolina reported using Airspace Saver"1 panels an average of 10 to 12 mo
(AS-l(C--S)), and the manufacturer has indicated that some panels have lasted over
18 mo. Similarly, COVKRTECH C-440's manufacturer indicated an average panel life
of up to 1 yr, and reported that one site in Ontario has already used a panel for
14 mo (CT-M(C-ll).
These cover systems are able to meet established criteria for daily cover
at the sites where they are currently being used. Operational considerations for
both products are summarized in Table 11A. By completely covering the wastes and
being very resistant to punctures and tears, access to insects, birds and
animalsf and blowing litter are effectively controlled. Although burrowing
animals could attempt to gain access to the waste along the edges of panels, the
material is reportedly too heavy for this to be of major concern, particularly
if the panel has been modified with a chain sewn into the edges to secure the
panel. Because the material is impermeable, odors are also effectively contained
(22). At one site, it was reported that after the panels had been left in place
for several days and then removed, a more intense odor was noted (AS-2(C-8)).
However,, it was emphasized that these odors occurred only for a brief period upon
removal of the panels, were restricted to the immediate area of the working face,
and emanated from the working face and not the panels. (It was also noted that
this effect was not much different than was observed when daily soil cover is
scraped from the working face prior to the start of the next operating day.)
Because the material is water-proof, it effectively sheds rainwater.
Cost—
The costs related to the use of these cover systems include the cost of
the panels, cost of any modifications, e.g., chain sewn in the edge, and cost of
any ancillary equipment that may be used to facilitate placement and removal of
the panels. These costs are summarized in Table 12A and 12B for Airspace Saver1"
and COVERTECH C-440, respectively.
4.3.3 Aqua-Shed" ;
Aqua-Shed™, marketed by Aqua-Shed Manufacturing Corporation, Florence, SC,
consists of a poly vinyl chloride (PVC) with an adhesive on one side, to enable
the panel to adhere to'wastes. According to the manufacturer, the product can
be used as both daily and intermediate cover. Aqua-Shed™ has been used at a site
in Hawaii for daily cover since January 1992. I
Material—
The cover system consists of 6-mil (0.15-mm) PVC panels coated on one side
with a polybutene emulsion. The material is also available without this
adhesive. This product was developed to provide a durable, long-lasting and
waterproof cover system for use as a daily and intermediate cover. Different
size panels, 18 by 30 ft (5.5 by 9.1 m), 18 by 60 ft (5.5 by 18.3 m), and 24 by
60 ft (7.3 by 18.3 m) , able to cover areas of 500 ft (46 m ), 1000 ft (93 m ) and
1,400 ft2 (130 m2), respectively, are available from the manufacturer (3). These
are shipped and stored in air-tight packages (to prevent the adhesive from
drying) until applied to the working face. A patent for this product is pending.
Placement and Retrieval— , :
Because of their smaller size and adhesive coating, placement of these
panels differs from other geosynthetic products. The panels are applied manually
by a two- to three-person crew that unrolls or unfolds the panels and places them
onto the waste as overlapping shingles until the entire working face is covered.
The manufacturer has indicated that after placement, the crew should walk over
the panels to ensure their adhesion to the wastes. Hence, crew exposure is
greater than would likely occur with other geosynthetic cover systems, since with
other products there is no requirement to walk on the panels after placement.
In addition, anchoring, such as tires, is being used at the site in Hawaii to
hold down edges and overlapped areas. Time required for placement and anchoring
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of pcinels is estimated to range from 5 to 10 rain per panel, depending on size and
wind conditions. Unlike other geosynthetic products, Aqua-Shed™, when used with
the adhesive coating, is not removed from the working face prior to the placement
of wastes the next operating day. Application considerations are summarized in
Table; 9A.
Impact of Climatic Conditions—
With the exception of high winds, climatic conditions do not significantly
impact the use of this material. High winds makes placement of these panels more
difficult, requiring additional personnel to extend and place the panels. The
adhesive coating on one side of the panel contributes to difficulties in handling
and placement of the panel under such conditions. :
Hot or cold temperatures reportedly do not impact the use of this product.
Aqua-Shed™ has been continuously used in hot weather for more than 10 mo (AQ-1(C-
9)). In addition, there were no difficulties reported with the use of the
product during a field demonstration conducted under freezing conditions (AQ-2(C-
9)). Climatic considerations related to the use of Aqua-Shed™ are summarized in
Tables 10A.
Performance—
Aqua-Shed™ has been used at one site since January 1992, and is considered
by the user to be an effective alternative daily cover which meets established
critesria. Although the site currently using Aqua-Shed™ primarily employed the
material as daily cover, according to the manufacturer, the panels can remain as
an effective cover for up to 3 mo. Operational considerations are summarized in
Table 11A.
The material, although thin, is durable enough to prevent puncturing and
tearing by animals. During a field demonstration, a steel-wheeled compactor was
unable to puncture the panels (AQ-2(C-9)). In addition, since the panels adhere
to the wastes or to other panels where overlapped, bird and animal access to the
waste along edges is effectively controlled. At the site using Aqua-Shed™, it
was noted that scavenging by animals had been reduced since the use of Aqua-Shed™
was initiated (AQ-l(C-9)).
Since individual panels are relatively small, ranging from 500 to 1,40O ft2
(46 to 130 m), multiple, overlapping panels are used until the entire working
face is covered, thereby effectively curtailing blowing litter. It was also
reported that odor emissions had decreased in areas of the site covered with
Aqua-Shed™ (AQ-1). Since these panels are not removed prior to the next
operating day, there is no sudden release of odor that has been reported to occur
at some sites when panels are removed from the working face on the succeeding
day. ,
Aqua-Shed™, although reported to be nonflammable and self-extinguishing
(3), is combustible, as are other geosynthetics. The site currently using Ac[ua-
Shed™ experienced a landfill fire and, although it was noted that Aqua-Shed™
would smolder in those areas where the fire reached the surface, it was not
considered to contribute ,to the spread of the fire (AQ-l(C-9)). However, beceiuse
of the low oxygen transmission rate of the material, it is able to effectively
curtail transfer of oxygen to the working face. These panels are not removed
from the working face prior to the placement of wastes onto the working face the
next operating day, but, because Aqua-Shed™ is combustible, it will not provide
an effective barrier to the spread of fire within the landfill, with the
exception of possibly reducing the access of oxygen.
Although Aqua-Shed™ can reduce infiltration of rainwater into the landfill,
it may impede leachate and gas movement. The waterproof panels can effectively
shed rainwater from the working face. However, because multiple small panels are
used, care must be taken when placing panels so that they are properly overlapped
to prevent rainwater from seeping into the wastes through gaps between panels.
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By leaving the panels in place, unless a deliberate effort is made to destroy the
o Zr'itiolSfl'1? Placement of wastes onto the working face on subsequent
movement within the cells. * may
Costs— ;
R»uai -TvK l°S* °f Aqua-Shed« panels are summarized in Table 12A. At the site in
X£niV ! " C?£rently ,USing Aqua-Shed- Panels, costs for both material and
labor to place the panels onto the working face, which are provided by a
contractor, averages $0.20/ft2 ($2.15/m2) (AQ-l(C-9)). it should be noted that
S^T^/JS*,*?1*, SitS ,rfnged from $S.OO-10.00/yd3 ($10.46-13.08/m3), i.e.,
$0.15-0.19/ft ($1.61-2.05/m2) of working face, not including labor or equipment
costs. Hence, operational cost savings were still obtained by using 1-his
product, even though the panels are not reused at the site (AQ-l(C-9)).
4.3.4 CORMIER.
P,.^, CORMIER geosynthetic cover materials, manufactured by Cormier Textile
Products, Inc., Sanford, ME, consists of high-density polyethylene, which is
woven reinforced and coated. It is currently being used at several sites
located in the Northeastern United States.
Material —
nuHo^-IV0^3^8 °f th*iS material are recommended for use as alternative cover
material by the manufacturer (12); WP-640, a 4.3 oz/yd2 (146 g/m2) material,
cross-woven with 8 x 9 yarns/in, (approximately 3x3 yarns/cm) , and WP-1440, a
5.2 oz./yd (176 g/m ) material, cross-woven with 12 x 12 yarns/in, (approximately
llLih?JnS£Cm)' -Thre materials are thin< lightweight, UV-resistant, and highly
SnSni » ,?<- "V*"86"1^ temperatures. The cross-woven yarn improves the
tensile and tear strength of the material and prevents punctures and tears from
SDlTGclCi.l.nC'
Panels for use as alternative daily cover are fabricated
_ e as aernave ay cover are fabricated by the
manVfaC^u5er ^° the desired sizes. Typical sizes of panels used are 6O. by ISO
heat- ealiL If ^ Z*,!*****1*?*** (22'9 by 45'? m) ' These are f^icated by
S?«2^ aling °* "-ft (4.6-m) wide sections. Custom detailing, consisting of
reinforcement of panel corners, is usually also provided.
Placement and Retrieval —
*«>„.• Becaufe the material is relatively lightweight, even the large size panels
fabricated from this material are not very heavy; a 60 by 150 ft (18 3 bv 45 7
m) panel of WP-640 weighs approximately 150 Ib (68 kg), and can be easily
,
unrollsrthea^ P1laCe? ma"uailv. by a three- to four-person crew that unfolds or
unrolls the panel and extends it over the working face. Placement of the panel
by a crew in this manner requires approximately 15 to 20 min. Alternatively,
°an a
. ,
c USin9 landfi11 equipment, e.g., compactor or dozer
face ShL m^hoH6 i^hS C,fVer b-y .drivin9 across °* adjacent to the working
face. This method, although requiring approximately the same amount of time,
reduces the number of personnel required and exposure to the working face.
A1lternative Met_hod of Placement— To facilitate the handling and placement
OI "ser at a fP*cial waste (sludge and flyash) landfill designed and
reel to deploy and recover the panel (CM-lt[C-
an
he
,->•> Q K ^ the: middle section of one edge of the 75 by 150 ft
i!!,*? y 45K? m) Panel iS attached to the reel, and hydraulic hoses from the
reel's gear box are connected to the hydraulic lines of the excavator to operate
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Figure 27.
Hydraulically operated reel used to place
and retrieve 75 by 150 ft (22.9 by 45.7 m)
CORMIER panel.
the reel. The panel is then folded into thirds along its length,: and retracted
onto the reel by using hydraulically-driven gears. The reel is then transported
to the working face by the excavator. Once in position, usually at the top of
the working face, a crew holds the end of the panel which is then unrolled aa the
excavator backs down the slope (Figure 28). After the panel is extended to its
required length, the overlapping sections are manually unfolded and extended
(Figure 29). According to the operator, use of this reel system not only
facilitates the placement and retrieval of the cover, but also decreases wear of
the cover, thereby extending its useful life (CM-l(C-lO)).
Anchoring— Once extended over the working face, because of its light
weight, the panel is held in place by sandbags or other anchoring that are
typically placed at 20-ft (6.1-m) intervals along the edges of the panel as well
as across the entire panel in a grid pattern. Approximately 30 to 40 sandbags
are used to secure a 75 by 100 ft (22.9 by 45.7 m) panel, with additional
sandbags or other anchoring used if high winds are anticipated (CM-l(C-lO)).
Retrieval— To retrieve the panel, the placement procedure is reversed.
Once the sandbags or other anchoring are removed, the panels are retrieved by
pulling them back over themselves to prevent snagging onto the waste, rolling or
folding, and then storing near the working face for subsequent use. Using the
hydraulically-operated reel, once anchoring is removed, the panel is folded into
thirds along its length and rolled back onto the reel with the assistance of the
hydraulically-driven gear box (Figure 30). Application considerations are
summarized in Table 9A.
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Figure 28. Panel being unrolled from reel during
placement onto ash/sludge working face.
Figure 29. Manual extension of panel over working face
after unrolling from reel.
85
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Figure 30.
Retrieval of panel by use of hydraulically
operated reel.
Impact of Climatic Conditions— '
Wind and snow are the only conditions that may significantly impact the use
of this alternative cover material., Rain and cold or hot temperatures do not
curtail its use.
The combined effect of the relatively light weight of the material, and the
large size of panels that are typically used, contribute to increased difficulty
in placement of the panel during windy conditions. Placement of the cover
becomes more difficult at wind! speeds of 8 to 10 mph (12.9 to 16.1 km/hr), and
will require the use of additional personnel to extend and secure the panel.
Although an infrequent occurrence at the site using this cover material, higher
wind speeds or gusty winds may prevent use. Windy conditions will also
necessitate additional time and effort to properly secure the cover so that it
will not be blown off the working face. This may involve the placement of soil
on the edge of the cover to prevent wind from getting underneath and lifting the
cover, or placement of additional sandbags along the edges at smaller intervals.
According to the manufacturer, another effect of wind that primarily
impacts the long-term effectiveness of this material, as well as other similar
lightweight materials, occurs when winds blow across the top of the cover
following placement and anchoring, causing areas between anchoring to be lifted
and to "flutter". Such "fluttering" purportedly will result in the gradual loss
of strength of the material over extended periods of use, e.g., > 6 mo (CM-M(C-
10)). However, this has not been indicated to be of significant concern at sites
using this or similar materials to date.
Neither rain nor freezing conditions adversely impact the use of this
material. The material is waterproof and rainwater is readily shed and not
absorbed. The material also maintains its flexibility in cold weather, and
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placement and recovery of the panel are not affected by such conditions.
Panels were easily deployed and remained flexible even at temperatures as low as
-15°F (~16°C), (CM-l(C-lO)). However, to prevent the possible loss or damage to
the panel, its use when snow is forecast is not recommended. Climatic
considerations related to the use of CORMIER are summarized in Table 10A.
Performance—
CORMIER cover materials have been used as alternative daily cover at
several locations in the Northeastern United States for approximately two years,
and its overall performance has been considered satisfactory. Users expressed
particular satisfaction with the ease of deployment, due both to its light weight
and flexibility, and its relatively long effective life. The panels were used
under all climatic conditions, with the exception of high winds or possibility
of snowfall. Because of its smooth texture and cross-woven yarns, the material
does not readily snag or puncture. If punctured, the material resists
development of long tears, because of the very closely-spaced, cross-woven yarins
that reinforce the material.
The manufacturer of the material indicated that the average effective life
for this material was 2 to 3 mo. One user, operating a special waste landfill
and employing the previously-described reel system, has used a 75 by 150 ft (22.9
by 45.7 m) panel for more than six months and anticipates an additional six
months of effective life (CM-l(C-lO)). This long effective life at this
particular site was partially attributed to the smoother working face that is
created by sludge and flyash disposal as compared to municipal solid waste, and
use of the reel system, which reduced wear and tear on the material.
The material meets established criteria for daily cover at the sites using
this product. It is considered particularly effective with respect to
controlling odors and moisture infiltration (CM-l(C-lO)). Operational
considerations are summarized in Table 11A. Once placed, the material completely
covers all wastes, effectively controlling access to insects, birds, and
burrowing animals, which are unable to penetrate or tear the material, and
blowing litter. It was also noted that birds do not land on the material (CR-
M(C-10) ).. Odors and other emissions are contained and rainwater effectively shed
due to the impermeability of the material. The smooth surface also minimizes
adherence of soil or wastes, e.g., sludges, which could otherwise add weight to
the material and make handling more difficult (CR-l(C-lO)). In addition, the
material is available with a fire-retardant finish and, because of its
impermeability, will prevent the transfer of atmospheric oxygen when placed onto
the working face (CR-M(C-IO)).
Costs—
Costs related to the use of CORMIER include the cost of panels and the cost
of any ancillary equipment that may be used to facilitate placement of panels.
These costs are summarized in Table 12A.
4.3.5 FabriSoil®
FabriSoil®, manufactured by Phillips Fibers Corporation, Greenville, SC,
is nonwoven polypropylene material, specifically engineered to satisfy
alternative daily cover material requirements. It has been available as a daily
cover since 1988, and is being used at approximately 50 sites located throughout
the United States.
Material—
FabriSoil® is composed of a 6 oz/yd2 (203 g/m2), nonwoven material made from
needle-punched polypropylene fibers, and is heat-sealed to provide a lightweight
material whose elongation characteristics make it resistant to tearing arid
punctures (4, 35). It is also claimed that FabriSoil® has a low moisture
adsorption capacity and is resistant to microbial attack.
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Panels are fabricated to site-specific requirements by sewing sections of
fabric together. The manufacturer recommends that panels be made 5 to 10 ft (1.5
to 3.0 m) larger than the dimensions of the working face to ensure complete
coverage of the waste. Typical panel sizes are 100 by 100 ft (30.5 by 30.5 m),
although smaller, 30 by 50 ft (9.1 by 15.3 m) panels, are also used. The maximum
recommended size is 150 by 150 ft (45.7 by 45.7 m). Sleeves can be sewn along
the edges of panels to permit steel rods or bars to be inserted into the sleeve
along the leading edge, thereby facilitating placement of panels.
Placement and Retrieval—
FabriSoil®, as with other large geosynthetic panels previously discussed,
is placed over the working face by lifting or dragging the panel either manually
or with landfill equipment. Because the size of panels typically used are 10,000
ft2 (930 m2) or greater, two pieces of landfill equipment, in conjunction with a
crew, are usually used to place the panel (35). For larger panels, greater than
14,000 ft2 (1,300 m), use of three pieces of equipment is recommended. Smaller
panels, 1,500 to 2,500 ft2 (139 to 232 m2), usually do not require any landfill
equipment and are placed manually by a two- to three-person crew. Time required
to place a 100 by 100 ft (30.5 by 30.5 m) panel averages 15 to 30 min, with
additional time required to place any anchoring (FS-1(C-12)).
The manufacturer indicated that at some sites using narrower, 30- to 50-ft
(9.1- to 15.3-m) wide panels, steel rods are inserted into the sleeve sewn along
the leading edge of the panel, and then the rod is attached to landfill equipment
with rope or chain to tow the panel across the working face. The rods are
usually left in place to hold down the edge of the panel on windy days.
Users of FabriSoil® indicated that the material is routinely anchored after
placement to prevent it from being blown off the working face and exposing the
waste. Discarded tires, placed at 20- to 30-ft (6.1- to 9.1-m) intervals, are
typically used for this purpose (4). Placement of anchoring averages an
additional 15 to 20 min for a .two- to three-person crew. Some sites used soil
to secure the edges of the panel, especially if soil was routinely used to cover
any exposed areas remaining along the edges of the panel after placement (FS-1(C-
12)). It was acknowledged, however, that if soil was placed on the edges, there
was an increased likelihood that panels could be torn, thereby decreasing their
effective life.
As with other gee-synthetics, FabriSoil® panels are retrieved;by reversing
the procedures used to place the panel. If soil is used to secure the edges,
removal of excessive soil with landfill equipment may be necessary before the
panels can be removed, thereby extending the retrieval time and increasing the
risk of damage to the panels. Application considerations are summarized in Table
9B. • -
Climatic Considerations—
Climatic conditions that have the most significant impact on both the use
and effective life of FabriSoil® are rainfall, freezing temperatures and wind.
Although able to shed water during moderate and heavy rainfall, several operators
have indicated that FabriSoil® absorbs moisture during rain events and becomes
heavier, making it difficult to maneuver and more susceptible to tearing and
punctures (FS-1(C-12), FS-2(C-'12)). In addition, when wet, soils tend to adhere
to the fabric, further adding to its weight and difficulty in handling. It was
also noted, however, that additional weight due to moisture could be an advantage
under windy conditions, since the panel would not be as susceptible to being
blown from the working face during placement, and may require less anchoring to
keep in place. , :
When freezing conditions exist, the placement and retrieval of FabriSoil®
may also become more difficult and time-consuming, and the effective life of the
panel may be reduced. Under such conditions, any moisture that may have been
previously absorbed by the panel may cause the panel to freeze to the underlying
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waste or onto itself and underlying soil during storage (FS-1(C-12), FS-2(C-12)).
Attempts to retrieve or move panels under these conditions will not only be more
difficult, but will also increase the likelihood of tearing the panel. As with
other geosynthetic products, its use is not recommended when snow Is predicted.
Although dependent on the size of panel used, windy conditions will make
placement of panels more difficult and time-consuming, requiring both greater
care and possibly additional personnel. Operators at one site that uses a 100
by 100 ft (30.5 by 30.5 m) panel reported increased difficulties in placing the
panel with winds in excess of 15 mph (24 km/hr). Climatic considerations related
to the use of FabriSoil® are summarized in Table 10B.
Performance—
The manufacturer has indicated an average effective life of FabriSoil® of
2 wk (4, 35). This has been substantiated at sites using the product under
varying climatic conditions. ; The operator at one site, who has used FabriSoil®
for approximately 5 yr, reported an average of 15 to 20 days use per panel, with
some panels lasting up to 30 days (FS-2(C-12)). Other operators have reported
the effective life of panels ranging from 7 to 30 days under similar climatic
conditions (FS-1(C-12)).
Operators of sites that have been using FabriSoil® have expressed general
satisfaction with the performance of the material and its ability to meet
established criteria for daily cover, including control of vectors, blowing
litter and odors, and reducing infiltration. Operational considerations are
summarized in Table 11A. Since the material is sufficiently resistant to
puncturing and tearing, birds and animals are deterred from attempting to claw
or peck through the panel, and blowing litter is effectively controlled.
FabriSoil® has also been demonstrated to be effective in controlling odors
emanating from the working face (22), as previously discussed in Section 4.3.1.
Users have also indicated that odors are effectively contained by the FabriSoil®
cover. One site reported that on those occasions when particularly odorous
wastes, e.g., produce and other food wastes, were received and subsequently
covered with FabriSoil®, that odor was effectively controlled (FS-1(C-12)). It
was also noted that when the panels were subsequently removed, equipment
operators and the crew were briefly exposed to a release of strong odor, which
quickly dissipated in the immediate area of the working face. (Such occurrences
are not considered unique to FabriSoil®, since similar releases of odor have also
been reported with other types of geosynthetic covers.)
Results of a flammability test designed to identify highly flammable
characteristics of textiles, conducted by Phillips Fiber Corporation on
FabriSoil®, indicated that FabriSoil® did not have any unusual burning
characteristics, and does not rapidly promulgate a flame across its surface (35).
Furthermore, moisture absorbed by the panel during rain events will decrease its
potential combustibility.
Depending on the intensity of rain events, FabriSoil® is able to shed water
from the working face, thereby minimizing infiltration into the landfill. in
addition, moisture absorbed by the panel can evaporate and not be available to
infiltrate into the landfill.
Costs-—
Costs related to the use of FabriSoil® include the cost of panels and the
cost of any ancillary equipment that may be used to facilitate placement of
panels. Panel costs are summarized in Table 12A. I
4.3.6 Griffolvn®
Griffolyn® geosynthetic cover materials, manufactured by Reef Industries,
Inc., Houston, TX, consist of low-density polyethylene reinforced with high-
strength nylon cord. According to the manufacturer, the materials have been used
since 1990 at several sites in Arkansas.
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Materials—
Although several types of this material are available, ranging in thickness
from 6 to 14 mil (0.15 to 0.36 mm), Griffolyn® TX-1200 is most frequently used
as an alternative daily cover because of its light weight, flexibility, and high
strength (41). TX-1200 is a three-ply, linear low-density polyethylene copolymer
and nylon yarn laminate. The nylon reinforcing, which provides uniform loading
resistance in all directions, and also resists the elongation of tears due to
punctures, is placed in a diamond pattern with 48 yarns/ft2 (517 yarns/m2) and is
suspended in a permanently flexible adhesive media to allow fiber slippage. This
material is also UV-stabilized, cold-crack resistant, and waterproof to withstand
extended exposure to various climatic conditions.
Panels for use as daily cover are fabricated by the manufacturer to desired
sizes up to 200 by 200 ft (61 by 61 m). Typical panels are 50 by 100 ft (15.3
by 30.5 m) , with edges sewn and grommets inserted. Other customized detailing,
such as sleeves along edges to facilitate insertion of steel bars, can also be
provided.
Placement and Retrieval—
Because the material is relatively light weight (a 50 by 100 ft (15.3 by
30.5 m) panel weighs approximately 170 Ib (77 kg)), and flexible, these panels
are typically placed manually by a two-person crew, by unfolding the panel and
extending it over the working face. At the sites using these panels, the size
of the working face is restricted to 30 by 80 ft (9.1 by 24..4 m), which not only
ensures that a 50 by 100 ft (15.3 by 30.5 m) panel will totally cover the waste,
but also reduces the need for the crew to walk on the working face while placing
the panel, thereby reducing the risk of injury and exposure to the waste (GF-1(C-
13)). Placement of a panel by a two-person crew averages 20 min. Although the
panel can also be placed by landfill equipment towing the panel across the
working face, this was determined to be unnecessary by site operators, as manual
placement was considered both simpler and less time-consuming.
Once the panel is extended over the working face, tires or other anchoring
material are placed along all the edges of the panel to prevent it from being
blown or lifted off the working face. At one site, it was reported that the crew
routinely placed anchors at 5-ft (1.5-m) intervals along the edges, since this
had been demonstrated to prevent the blowing or lifting of the panel, even at
winds of 50 mph (80 km/hr). Placement of anchors in this manner reportedly
requires a two-person crew 25 min to complete (GF-1(C-13)). ;
To retrieve the panels, tires or other anchoring are first removed and
returned to the stockpile area. The panel is then removed from the working face
by pulling it back over itself to prevent snagging, folding it, and storing it
near the working face for subsequent use. Application considerations are
summarized in Table 9B. ;
Impact of Climatic Conditions—
Wind is the only climatic conditions that is reported to significantly
impact use of this material. Rain, freezing temperatures, or hot weather do not
curtail its use, since the material is waterproof, cold-crack resistant, and UV-
stabilized, and designed for extended exposure to adverse weather conditions.
As with other lightweight materials, such as CORMIER, windy conditions can
make placement of the panels more difficult, requiring additional labor and time.
However, the relative impact of wind is also dependent upon the size of the
panels used, i.e., the larger the panel, the more difficult it is to handle. A
site using 50 by 100 ft (15.3 by 30.5 m) panels did not indicate wind as a
significant problem during placement of panels if a sufficiently large crew was
available and proper care was taken during deployment and placement of the panels
\
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As with other geosynthetics, to prevent possible loss or damage, the panels
should not be used if snow is predicted. However, removal of snow from panels
has been accomplished at some sites following a light, less than 2-in. (5-cm),
snowfall (GF-1(C-13)). Removal of the snow was apparently simplified by the
smooth finish of material which allowed the snow to easily slide off the panel.
Freezing of the material to underlying wastes during cold weather has not been
reported as a problem. However, freezing conditions were also not a frequent
occurrence at these sites. Climatic considerations related to the use of
Griffolyn® are summarized in Table 10B.
Performance—
Griffolyn© cover materials have been used as alternative daily cover for
more than 2 yr at several sites in Arkansas, and the overall performance has been
satisfactory. Users expressed particular satisfaction with the ease of deploying
and retrieving panels. Their light weight, flexibility, and durability reduces
snagging and puncturing of the panels, which helps extend the effective life.
When punctured, the cross-webbed nylon reinforcing prevented the extension of
tears. Such punctures and tears were also repaired by using special patching
tape available from the manufacturer, which purportedly further extends the
effective life of the panels. One site was reported using the same panel for 10
mo, while another site had used a panel for over 2 yr (GF-1(C-13)).
Users also considered the material as being effective in meeting
established criteria for daily cover and exceeding soil cover in certain aspect S3,
such as odor control and minimizing infiltration. Operational considerations are
summarized in Table 11B. Since the nylon reinforcing prevents punctures from
being extended, vector access to the wastes and blowing litter are effectively
controlled. Moreover, the material is relatively impervious, odors and other
emissions are contained (22), and rainwater is effective shed from the working
face as long as the cover remains in place. As with other cover systems,
although Griffolyn® panels prevent the transfer of atmospheric oxygen to the
working face, the material is combustible.
Costs—
The cost of Griffolyn® panels are summarized in Table 12B. Because these
panels are usually manually placed, use of ancillary equipment to facilitate
placement has not been reported at sites currently using this product.
4.3.7 Polvfelt
Polyfelt XOOlO-Daily Coverfelt is a nonwoven polypropylene fabric
manufactured by Polyfelt, Inc., Evergreen, AL. This material has been available
since 1990, and is currently being used at approximately 30 landfills in the
Midwestern United States.
Mater icils—
Polyfelt X0010 consists of spun-bonded, continuous filament, needle-punched
polypropylene (37). The 8 oz/yd (271 g/m ) nonwoven fabric is highly durable and
has been thermally treated to reduce its permeability and provide for a smoother
finish.. Fabricated panels are available in various customized sizes to meet
site-specific requirements. Typical panels are 100 by 100 ft (30.5 by 30.5 m),
although smaller, 20 by 60 ft (6.1 by 18.3 m) panels are also used.
Placement and Retrieval—
As with other geosynthetics materials, these panels can be manually placed,
by using landfill equipment to tow the panel across the working face, or by using
skid-mounted rollers to roll panels onto the working face. At one site, 100 by
100 ft (30.5 by -30.5 m) panels were placed with compactors in 30 min (PF-2(C-
14)). The operator at another site indicated that 20 by 60 ft (6.1 by 18.3 m)
panels were placed onto a 20,000 to 23,000 ft2 (1,860 to 2,140 m ) working face
using multiple skid-mounted rollers. The rollers were fabricated on-site from
20-ft (6.1-m) sections of 24-in. (61-cm) diameter conduit. Panels are attached
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to the conduit with 2 by 4 in. (5 by 10 cm) lumber. A compactor tows the skids
to the top edge of the working face and a four-person crew unrolls the panels
down the slope. Approximately 30 to 40 min are required to cover the working
face. Application considerations are summarized in Table 9C.
Climatic Considerations—
Rain, freezing conditions, and wind reportedly can impact the use and
effective life of Polyfelt. Although the material absorbs moisture during rain
events, making it heavier and more difficult to handle and place (PF-1(C-14)),
it apparently does not absorb as much moisture as some other nonwoven materials
(PF-2(C-14)). During wet, freezing conditions, problems with panels freezing to
the underlying waste and subsequent difficulties in removal of the panels were
reported (PF-1(C-14), PF-2(C-14)). With winds greater than 20 mph (32 km/hr),
difficulties in placing 100 by 100 ft (30.5 by 30.5 m) panels were also reported
(PF-2(C-14)). However, the use of rollers permitted the placement of smaller,
20 by 60 ft (6.1 by 18.3 m) panels at winds in excess of 30 mph (40 km/hr) at
another site (PF-1(C-14)). Climatic considerations related to the use of
Polyfelt are summarized in Table IOC.
Performance—
Polyfelt has been used at various sites in the Midwestern United States for
up to 3 yr. According to the manufacturer, panels have been reported to last 6
to 9 mo. The longer effective life of Polyfelt, compared to some other nonwoven
materials, was attributed to the continuous filament used in the fabrication of
the panels to increase its durability and reduces moisture retention. The
operator of one site, who places panels with rollers, indicated an average of 20
to 30 uses per panel with some panels lasting 3 to 4 mo (PF-1(C-14)) 1 At another
site, panels placed with compactors were reported to last more than 3 mo if
proper care was taken during placement and retrieval of panels (PF-2(C-14)). One
operator indicated that Polyfelt lasted longer than other nonwoven materials theit
were previously used at the site when used under similar climatic and operational
conditions (PF-2(C-14)).
Operators of sites using Polyfelt indicated general satisfaction with the
material and its ability to meet established criteria for daily cover (PF-1(C-
14), PF-2(C-14)). Operational considerations related to the use of Polyfelt are
summarized in Table 11B. The material was considered to be effective eit
controlling bird and animal access and blowing litter when properly applied to
cover the. working face. Odors were also reported to be effectively contained.
Its ability to shed water from the working face during rain events was considered
comparable to that of soil cover (PF-1(C-14)).
Costs—
Costs related to the use,of Polyfelt include the costs of the panels and
any ancillary equipment that may be used to facilitate their placement arid
retrieval. These costs are summarized in Table 12C.
4.3.8 SaniCover™
SaniCover™, marketed by Fluid Systems, Inc., Cincinnati, OH, consists of
both polypropylene woven (SaniCover™ 250) and nonwoven {SaniCover™ 150) cover
materials, fabricated from materials which are manufactured by Amoco Fabrics and
Fibers, Co., Atlanta, GA. SaniCover™ has been available since 1991 and is
currently being used at various sites throughout the United States. Other sites
purchase the Amoco fabric directly from distributors and fabricate their own
panels. :
Materials—
Although both SaniCover™ 150 (a.k.a., Amoco 9298) and SaniCover™ 250
(a.k.a., Amoco 2006) are made from 100% polypropylene, and weigh 6 oz/yd2 (203
g/m ), they differ with regard to their physical properties and performance under
various climatic and operational conditions (20). SaniCover™ 150 consists of a
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nonwoven, needle-punched fabric whose elongation characteristics reduce tearing
and puncturing. SaniCover™ 250 consists of a woven, water repellent fabric,
making this material better suited for rainy climates.
SaniCover™ panels are custom-fabricated by sewing sections of the Amoco
fabric: to site-specific requirements. Panels typically range from 75 by 80 ft
(22.9 by 24.4 m) to 100 by 100 ft (30.5 by 30.5 m), although larger panels, e.g.,
75 by 15.0 ft (22.9 by 45.7 m), are also used at some sites (SC-2(C-15)). These
panels may also have pockets added along the edge, i.e., a hem sewn along an edge
of fabric, which allows the insertion of steel bars or rods to facilitate
placement of the panel.
i
Operators at some sites have indicated a preference to purchase large rolls
of the material and either fabricate their own panels by sewing sections together
to construct a larger panel on site, or to use several smaller panels by cutting
sections directly from rolls of fabric without further fabrication (SC-3(C-15),
SC-4(C-15)).
Placement and Retrieval—
As is typical for most covers, both of these materials can be placed over
the working face by lifting and dragging the panels either manually or by using
landfill equipment. Because of the size of panels typically used at landfills,
e.g., 6,000 to 11,000 ft2 (557 to 1023 m2), they are usually placed by using two
pieces of landfill equipment in conjunction with a crew. Placement of panels in
this manner averages 15 to 20 min, with additional time required to anchor the
panels. Operators at one site reported using smaller panels (1,000 to 1,200 ft
(93 to 111 m2) consisting of sections cut directly from rolls of fabric, which
are then manually placed onto the working face by a six- to eight-person crew
(SC-4(C-15)).
There is some variation in practices related to anchoring of the panels,
based on the type of material used and climatic conditions. At sites using
SaniCover™ 250, panels are routinely anchored, since even light winds of 5 to 10
mph (8 to 16 km/hr) are able to lift and blow the panel off the working face (SC-
1(C-15)). Because it is water-repellant, SaniCover™ 250 does not retain moisture
and hence remains relatively lightweight even with continued use, thereby
necessitating anchoring. At sites using SaniCover™ ISO (nonwoven material), use
of anchoring varied with climatic conditions, e.g., probability of rain and/or
high winds. Since SaniCover™ 150 tends to absorb moisture and becomes heavier
with use, at some sites, anchoring of the panel was not considered necessary
unless winds in excess of 20 mph (32 km/hr) were expected (SC-3(C-15)).
Anchoring is usually performed by placing discarded tires or sandbags both
around the perimeter of the panel, and onto the panel at 20- to 30-ft (6.1- to
9.1-m) intervals. This typically requires a two- to three-person crew 10 to 15
min to accomplish (SC-l(C-lS)). Alternatively, at some sites, panels are
anchored by placing soil on one or more edges of the panel (SC-2(C-15)). Use of
soil for anchoring in this manner is normally performed in conjunction with
placement of soil cover onto areas of the working face that remain exposed after
placement of the panels, i.e., the size of the working face is larger than the
panel.
Retrieval of a SaniCover™ panel is performed in a manner similar to that
used with other covers, which is essentially the reverse of the procedure used
to place the panels. Anchoring, if used, is removed first. The panel is then
removed, either manually or with landfill equipment by pulling it back over
itself to minimize snagging and tears, and storing it near the working face for
subsequent use. Application considerations are summarized in Table 9C.
Impact of Climatic Conditions—
Climatic conditions reported to impact the use and longevity of SaniCover™
as an alternative daily cover include rainfall, freezing conditions, and high
winds.
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The impact of rainfall differs between SaniCover™ 150 and 250. Because
SaniCover™ 250 is water-repellant, it does not absorb moisture and, hence, its
use is not curtailed by rainfall. Operators of several sites, however, have
reported that SaniCover™ 150 absorbs moisture and becomes heavier durina rain
events (SC-l(C-lS), SC-2(C-15), SC-3(C-15)). Soil was also reported to adhere
m?^f.re y t0 the fabric under such conditions. This makes the material more
difficult to maneuver and more susceptible to punctures and tearing, thereby
decreasing its effective life. *
When freezing conditions exist, if SaniCover 150™ has absorbed moisture
it can freeze to portions of the underlying waste, or to the soil if freezing
conditions develop while the panel is stored near the working face durina the
operating day (SC-l(C-lS), SC-2(C-15)). Under such conditions; the retrieval or
placement of the panel will be difficult and time-consuming, and will increase
the likelihood of tearing of the fabric.
The impact of freezing conditions on SaniCover™ 250, which does not absorb
moisture, is reported to be less significant. One site, however, indicated that
moisture trapped between the working face and the cover would occasionally freeze
^o^P?5bi?ns °f the underlVina waste, making removal of the panel more difficult
(SC-l(C-lS)). These occurrences are not considered to be unique to this product,
but would be expected to occur with most such cover materials under similar
conditions. Also, as with other geosynthetic cover materials, the use of these
materials (SaniCover™ 150 and 250) is not recommended when snow is predicted.
Operators at one site indicated that light, 5 mph (8 km/hr) winds could
actually facilitate placement of panels by slightly lifting the panels if the
leading edge was oriented into the wind as the panel was being placed onto the
working face. Winds greater than 25 mph (40 km/hr), however, made placement of
panels more difficult and required more labor and time to accomplish (SC-2fC-
15)). Despite the additional labor and time that may be required, smaller panels
have been successfully placed at winds of 30 mph (48 km/hr) at some sites (SC-
4(C-15)). Climatic considerations related to the use of SaniCover™ are
summarized in Table IOC.
Performance—
SaniCover™ has been satisfactorily used as an alternative daily cover under
various climatic conditions at landfills located throughout the United states
The manufacturer indicates that panels can be effectively used for 30 days 'or
?°r!!;.,At Sites located in the Northeastern United States, which typically used
landfill equipment to place SaniCover™ 150 and 250 panels, the effective life of
panels averaged 20 days, with some panels lasting up to 30 days (SC-l(C-lS) SC-
2{C-15). At these sites, the most significant factors influencing the effective
life of panels were operator care taken in the placement of the panels,
smoothness of the working face by compaction and removal of protruding objects
and climatic conditions such as snow, rain, freezing temperatures, and wind
These users also indicated that rain and freezing conditions had a more
significant impact on SaniCover™ 150 than SaniCover™ 250, since they made this
material more susceptible to tearing. In drier, warmer climates, SaniCover™ 150
was reported to have a much longer effective life. At a site located in the
Southwestern United States, 15 by 75 ft (4.6 by 22.9 m) manually-placed panels
were reported to last 4 to 5 mp (SC-4(C-15)). Another site in the Southeastern
United States reported using SaniCover™ 150 panels an average of 4 mo by
repairing tears on site (SC-3(C-15)). *
Users have expressed general satisfaction with the performance of both
materials (SaniCover™ 150 and SaniCover™ 250) and their ability to meet criteria
established for daily cover. Operational considerations are summarized in Table
ilB. Eloth materials are sufficiently durable to curtail puncturing or tearina
by animals or birds, thereby preventing their access to the wastes. They also
effectively control blowing litter. Although both SaniCover™ 150 and 250 are
permeable and hence allow venting of gases and vapors, they are reported to be
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effective at controlling odors emanating from the working face (SC-2(C-15), SC-
3(C-15)). The operator of one site indicated that SaniCover"1 150 became odorous
with extended use (> 20 days), particularly if the fabric was moist, but this was
only noticeable in very close proximity to the fabric and did not affect the
material's ability to.suppress odors emanating from the working face (SC-2(C-
15)). Because it is water repellant, SaniCover1" 250 is considered more effective
in shedding water from the working face and, hence, is recommended for use in
areas where the occurrence of rain events is more frequent. SaniCover™ 150 will
initially absorb water during rain events, similar to soil cover. However,
depending upon the intensity of the rain event, it will subsequently shed water
from the working face (SC-l(C-lS), SC-2(C-15)). Furthermore, moisture absorbed
by SaniCover1" 150 can be evaporated and thereby not infiltrate into the landfill.
Although both materials are combustible, the likelihood of combustion is
considered to be less for SaniCover" 150 when it has been exposed to rainfall and
has absorbed moisture.
Costs—
Costs related to the use of this product include the cost of panels and the
cost of any ancillary equipment that may be used to facilitate their placement.
The cost of fabricated SaniCover1" ISO and 250 panels are summarized in Table l.'2C.
4.3.9 Typar®
Typar® Geotextiles, manufactured by Reemay, Inc. and marketed by Exxon
Chemical, both from Old Hickory, TN, consist of a group of nonwoven, thermally-
spunbonded polypropylene fabrics, which have various road construction and
landfill applications. Selected types of this product have been used as
alternative daily cover at approximately 30 landfills located throughout the
United States since 1990.
Materials— !
This material is being used as a daily cover because of its light weight,
high tensile strength, tear and puncture resistance, and low moisture-absorptive
capacity (17). Typar® Style 3601, a 6 oz/yd2 (203 g/m2) fabric, has been used at
most of the sites to date. According to the manufacturer, a lighter-weight,, 4
oz/yd (136 g/m ) material, Typar® Style 3401, although currently not widely used,
has similar properties and is also able to be an effective daily cover.
Fabricated panels are available from the manufacturer in a standard size
of 46 by 100 ft (14.0 by 30.5 m), although larger-sized panels, up to 200 by 200
ft (61 by 61 m), can be fabricated to meet site-specific requirements. Straps
can also be added at 10- to 15-ft (3.0- to 4.6-m) intervals to facilitcite
handling of panels. Alternatively, sites can obtain rolls of fabric and
fabricate panels on-site using portable sewing machines (46).
Placement and Retrieval— •
As with other geosynthetics, these panels can be placed either manually or
by using landfill equipment to lift and tow the panels across the working face.
The-manufacturer indicated that a panel can be placed manually by a three- to
four-person crew within 15 to 20 minutes. At one site a panel was placed within
10 min using one compactor and a two- to three-person crew (TP-1(C-16)). Because
of their relatively light weight of 4 to 6 oz/yd2 (136 to 180 g/m2), anchoring is
typically used with these panels. This may require an additional 10 to 20 min
to accomplish.
Skid-mounted rollers have also been used at another site to facilitate the
placement of panels (TP-2(C-16)). Sections of 3-ft (0/9-m) diameter conduit were
used to fabricate 30-ft (9.1-m) long rollers which were then placed on skids to
allow towing to and from the working face. The site uses two such rollers to
place 30 by 50 ft (9.1 by 15.31m) panels. To place the panels, one edge remains
anchored to the skid while the conduit is rolled across the working face.
Placement of panels in this manner is normally accomplished by a three- to four-
person crew in 15 to 25 min, including anchoring of the panels with sandbags.
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Panels are retrieved similarly to the other geosynthetics previously
discussed by removing anchoring and pulling the panel back over itself to
minimisse snagging. Panels placed by using rollers are retrieved by rolling the
conduit section, with panel attached, back up to the skid. Depending upon the
slope of the working face, this may be more difficult and require additional time
and labor than the initial placement of the panel. Use of rollers has been
demonstrated to extend the effective life of panels (TP-2(C-16)). Application
considerations are summarized in Table 9C.
Climatic Considerations—
V/ind and freezing rain are reportedly the only climatic conditions that
adversely impact use of this material. Operators have reported encountering more
difficultly in placing panels under windy conditions (TP-1(C-16), TP-2(C-16)),
although panels were placed at winds exceeding 40 mph (64 km/hr). Additional
labor and more time were retired under such conditions. At one site, which
normally used a compactor in conjunction with a crew to place the panels, it was
determined that the panel was easier to control if placed manually under windy
conditions (TP-1(C-16)). Freezing rain was also reported to occasionally affect
placement or retrieval of panels due to the added weight. At a site located in
Illinois, where snow and freezing temperatures can be a frequent occurrence, an
alterneitive working face was used if the panel could not be retrieved due to
these conditions (TP-2(C-16)).
Bain reportedly does not significantly impact on the use of Typar®.
Although the material absorbs some moisture during rain events, because of its
low water-absorptive capacity {maximum of 50% by weight), the weight of the panel
does not increase enough to significantly impact handling, placement and
retrieval of panels (TP-1(C-16), TP-2(C-16)). Climatic considerations related
to the use of Typar® are summarized in Table IOC.
Performance— •
Typar® has been used at some sites for over 2 yr. Operators have expressed
particular satisfaction with the ease of deployment and durability of the
material. A site in Colorado averaged 50 uses (approximately 2 mo) from a 100
by 125 ft (3O.5 by 38.1 m) panel before it required replacement (TP-1(C-16)).
Operators at other sites have reported panels remaining effective as a cover for
at least 2 mo and even longer if on-site repairs are made (46). The operator of
the site that used skid-mounted rollers to place and retrieve 30 by 50 ft (9.1
by 15.3 m) panels indicated that panels could last 8 to 10 mo (TP-2(C-16)). Use
of rollers and care taken by personnel, both in working face preparation and
panel placement, were considered to be the primary reasons for the extended
effective life of these panels.
Overall, Typar® was considered to be effective at meeting the established
criteria for daily cover. Operational considerations are summarized in Table
11B. Although access to vectors is effectively controlled by the panel, at the
site where panels were used for long periods of time, e.g., 8 to 10 mo, the
panels reportedly became odorous and attracted insects (TP-2(C-16)). This was
primarily attributed to the length of time that these panels were being used,
since at other sites where panels were not used as long, e.g., an average of 2
mo, insect problems were not reported. This is not considered to be unique to
this product, as users of other geosynthetic materials have reported similar
problems with extended use of panels (SC-2(C-16)). It was also noted that these
panels remained effective in controlling odors emanating from the working face
throughout their effective life. The panels are not waterproof and may initially
absorb some moisture during a rain event. However, depending on the intensity
of the rain event, the material will shed rainwater from the working face and
reduce infiltration into the landfill. Operators considered Typar® to be much
more effective than soil in minimizing moisture infiltration (TP-1(C-16)).
Costs—
Costs related to the use of Typar® include the cost of the panels and of
any ancillary equipment that may be used to facilitate their placement. These
costs aire summarized in Table 12C.
i 96
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SECTION 5
INDIGENOUS MATERIALS
i
= K v, A y.arietv.0f indigenous materials are currently used as ADCMs, including;
ash-based materials, shredded ;automobile components and tires, digested sludq4
and sludge-derived products, dredged material, foundry sand, petroleum-
™™a™Ln ? soils, and shredded green waste. Unlike commercially available
ADCMs, each of these materials can vary significantly with respect to physical
and chemical characteristics and composition, depending on its particular source.
In addition, suitability and acceptability are dependent on site-specific
climatxc and operational conditions and regulatory retirements. Hence, only k<=y
factors and considerations related to the use and performance of these materials
are presented in this section. i«ai.«siieixs
5.1 GENERAL CONSIDERATIONS
Many indigenous materials are locally generated waste products that have
been disposed of in landfills prior to being approved for use as ADCMs. To be
acceptable as ADCMs, most of these materials have been physically and/or
chemically modified {i.e., shredded, dried, blended with soil or conditioned wil-h
lime), or require evaluation for the presence of potentially hazardous
constituents (e.g., heavy metals) prior to use.
The direct benefits of using indigenous materials as ADCMs can include
savings in landfill capacity and soil costs, and the additional tipping fees from
receiving these materials at the landfill. Although indigenous materials are
;fvpi~. ly aPPlied at the same (°r greater) thickness than soil cover, savings in
landfill capacity can still be attained, since many of these same materials would
otherwise occupy space within the landfill as a waste material, not as a daily
coyer. Therefore, by using what was previously considered a waste material as
daily cover, the need for a 6-in. (15-cm) soil cover may be eliminated and that
equivalent landfill capacity is correspondingly saved. In addition, both the
soil that would otherwise be required for daily cover and costs associated with
soil excavation and movement are also saved. Furthermore, many landfills charqie
a tipping fee, although usually at a reduced rate, for accepting the waste
material that may be used as an indigenous ADCM at the landfill. The economic
feasibility of using an indigenous material as an ADCM may also be enhanced by
offsetting equipment and operational costs that may be associated with these
materials, e.gj, shredder to shred tires.
The feasibility of using an indigenous material as an ADCM also depends on
local availability in sufficient quantities on a regular and continuous basis.
If these conditions are not met, the necessary capital investment and operating
costs, additional analytical requirements, or other costs associated with their
use may not be operationally or economically justifiable. As with soil and
commercially available alternative cover materials, working face preparation and
care taken in placing the cover material are important factors that impact the
acceptability and effectiveness of indigenous daily cover materials
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Mrt<=4. .ln.manv resPects, indigenous cover materials are similar to soil cover.
Most indigenous materials are transported to and applied onto the working =Jce
in a similar manner as soil, i.e., trucks are used to transport the material to
the working face and dozers are used to spread it onto the workingft ice
Indigenous materials are also applied at approximately the s^e ™ in uf cmi
££5l?U ^ S°* 'I Climatic ^nditions can also impact the Se of indigenous
moS *•«*• it *imilaf man"e.r' For Cample, rain makes many indigenous matir als
^onHit^ ° aPPly at£ increases infiltration potential, while dry and w ndl
conditions can cause problems with the generation of dust. Furthermore nianv
indigenous materials, such as contaminated soils and foundry sand, arTselected
principally because their composition and performance characterTstics as a dailv
cover are similar to that of soil. However, some indigenous ma?erillsaisJ
™^V°ntaf ?antn ^hSt COXild be leached bv "^wat^ a9nd thereby affect thl
a^E ? nV leachate and its subsequent disposition, although the impact of
such leachate contaminants on landfill stabilization would probably be minor
Climatic and operational considerations related to currently used indigenous
materials are summarized in Tables 13A and 13B, and 14A and 14B?respective?y?
5.2 CURRENTLY USED INDIGENOUS MATERIALS
5.2.1 Ash-based Materials
^^^^
such as heavy metals, prior to use is
Moisture content affects both the workability and performance of ash-ba<3ed
sx^V-"-^^^^^^^^
S?J«r^r"°^^^^^^
nancii-Lng and problems with the generation of dust have been reported (39, iM-lfC-
»?Jt>:*- r materials are not considered combustible unless they contain
significant amounts of partially burned materials (39). Theirab^litvtS
minimize infiltration is dependent upon the materials with which they are blende?
and compaction provided during placement. Y mended
5.2.2 Automobile Recycling Fluff
Automobile recycling fluff consists of shredded, nonmetallic:(e.g., fo=un
r, plastic) automobile parts f391. Howew^. because these materials can be
reired
and monitoring for such constituents are usulll?
fi»ff Raf^d°?v "Ot significantly affect the workability of automobile recycling
fluff since it is a relatively permeable material and many of its constituent!
Sin readily absorb moisture. It is, however, not very effective at shedding
w!th T£ f use ^C°0nfseSff1yvmo.is1ture infiltration into the landfill can.increasl
witn 1-he use of this material. Because the material contains combustible
components, such as foams and plastics, their f lammability may increase ^derdrj
f ™ *i ^i9h^er comP°nents such as foam are also more prone to being blown
from the working face under dry, windy conditions. oiown
5.2.3 Dredged Materials
tediments from lakes or rivers as ADCMs has also been
f-o so een
uni-o «( I'*. )>' **?*****"* to dredging, the bottom sediments are stored for
up to 48 hr, depending on the composition of the sediment and climatic
i
98
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99
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conditions. This allows the material to dry and facilitate subsequent placement
onto the working face, and also enables a reduction in odors (39). Since bottom
sediments can be contaminated with pollutants such as herbicides and pesticides,
analysis of sediment samples is necessary before it can be accepted for use as
an ADCM (39).
Once dried and accepted, dredged materials are placed onto the working face
similar to soil cover. If the sediment is not properly dried, or if used during
rain events, difficulties in the workability of the material can be encountered.
Under dry, windy conditions, dust problems can also be encountered (39).
5.2.4 Foundry Sand -
Certain types of sand resulting from discarded casting dies at foundries
is permitted for use at several landfills (39, IM-3(C-17), IM-4(C-17)).
Depending upon the metals used for casting, their concentrations in the foundry
sand, and the binding agent used to maintain form during casting, analysis for
potential hazardous constituents is usually conducted to screen foundry sands
prior to their acceptance as a daily cover (39).
Foundry sand has a similar composition as a sandy soil. Hence, moisture
content does not have a significant impact on its workability, and it can be
applied without difficulty during rain events (IM-6(C-17)). It is, however, not
as effective as other less permeable soils at shedding water from the working
face, and can allow infiltration to enter the landfill. In addition, during
heavy rains, foundry sand is susceptible to erosion (39). Consequently, it is
not used on external slopes (IM-6(C-17)). During dry, windy conditions, problems
with increased dust generation have also been reported (39, IM-3(C-17), IM-6(C-
17)). -
5.2.5 Green Waste/Compost
Green waste, such as tree trimmings, grass clippings and garden wastes,
shredded into particles of 3 in. (7.5 cm) and smaller, usually by a tub grinder,
is also used as ADCM (8, 24). Since green waste is difficult to handle and to
compact, significant landfill capacity savings are obtained by shredding the
material and reducing its volume before using it as daily cover. In addition,
soil that would otherwise be used as cover is preserved (8). These savings, and
the fees charged for accepting green wastes can offset the additional costs
incurred during processing prior to use as a daily cover.
Green waste is being used as an ADCM during dry weather conditions at
landfills located in Los Angles County, CA (8, 24). A 12-in. (30-cm) layer of
noncomposted, shredded green waste has been demonstrated to meet cover criteria
related to controlling vectors, litter and odors. Because the material is not
effective at shedding water from the working face, it is only used during dry
weather and may not be suitable for areas with frequent rainfall.
With regard to fire retardation, although green waste is combustible,
moisture retention averaging 40% and shreddeding and compaction tend to reduce
oxygen transfer to the working face and the possibility of fire. No incidences
of fires accountable to the use of green waste as cover material have been
reported (8).
The use of composted green waste, either by itself or after being blended
with soils or wood wastes, has also been reported (39). However, the additional
operational costs, both in compost equipment and labor, and other more beneficial
uses for composted green waste, may limit its use as daily cover (8, IM-4(C-17)).
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5.2.6 Petroleum-contaminated Soils
Petroleum-contaminated soils, which may result from excavation of leaking
underground storage tanks (USTs), have also been permitted for use as an ADCM at
several landfills (39, IM-7(C-17)). Since petroleum-based products are
biodegradable, use of petroleum-contaminated soil does not present a significant
environmental risk, as these products can be degraded within the landfill
environment. However, because the types and concentration of contaminants will
vary depending on source, analyses are routinely required to demonstrate
acceptability as a daily cover material.
With the exception of being contaminated with petroleum products, such
soils are used and perform similar to conventional soil cover. Some sites
reportedly store the contaminated soils on-site prior to use to encourage release
of volatile contaminants (IM-7(C-17)).
5.2.7 Shredded Tires
Since the disposal of ftires is being banned by an increasing number of
regulatory agencies, landfills have determined that stockpiling tires, shredding
them at periodic intervals, and using the resultant material as an ADCM is an
economically feasible and acceptable alternative for both disposing of tires and
providing daily cover (IM-7(C-17)). The tipping fees received for accepting
tires, volume reductions obtained by shredding the tires, and soil savings
resulting from using shredded tires as a cover material offset the processing
costs incurred in shredding the tires (IM-2(C-17)). When properly placed as a
6-in. (15-cm) layer, shredded tires are effective at controlling vectors, litter,
dust and odors. Shredded tires are reportedly easier to handle and place onto
the working face under adverse climatic conditions, e.g., rain and freezing
temperatures, than soil (IM-2(C-17)). However, because the resultant cover does
not readily compact and is permeable, it is not effective at shedding moisture
from the working face and moisture infiltration into the landfill can increase.
Shredded tires are also combustible. Moreover, an increased occurrence of
vehicular tire punctures from fragments of the steel reinforcing from the waste
tires can also become an operational concern unless proper traffic controls are
established (IM-7(C-17)).
5.2.8 Sludges and Sludge-derived Products
Sludge and 'sludge-derived products are both currently being used as
alternative materials for daily cover at landfills. Digested sewage sludge has
been successfully used at landfills as an ADCM, resulting in both increased
landfill capacity if the sludge would otherwise be disposed in the landfill, and
soil savings. When dried, sludge can be applied without difficultly as an
effective cover. During heavy rains, however, the material becomes difficult to
handle and drive across with.landfill equipment. Odor problems have also been
reported with the use of sludges (IM-5(C-17)).
To improve workability and reduce odors, sludges have been mixed with soil
or compost at several landfills (39). Alternatively, sludges can be treated by
chemical fixation processes using various additives such as lime, cement kiln
dust, fly ash and silicates to produce a suitable soil-like material for daily
cover and other uses, while reducing environmental and operational concerns
associated with disposal of sludges (9, 39, 48, IM-4(C-17)). The use of such
sludge-derived products (SDPs) as ADCMs offers opportunities for environmentally
sound disposal of sewage sludges, while also meeting daily cover requirements.
Several technologies for transforming sludges into usable agricultural and
construction products, including landfill cover material, are presently
available. Typical of such technologies are the N-VIRO process and CHEMPIX®
process (9, 32, 48).
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The N-VIRO process, formally called "Advanced Alkaline Stabilization with
Subsequent Accelerated Drying (ASSAD)", is a pasteurization and chemical fixation
process, patented by N-VIRO Energy Systems Limited, Toledo, OH. In this process,
dewatered sludge is blended with alkaline additives (lime and cement kiln dust)
The blended mixture is then cured for at least 12 hr, during which time the
product temperature is maintained above 22°F (50°C). To further dry the mixture,
it is subsequently aerated and windrowed for 3 to 12 days, depending on climatic
conditions and its end use, while maintaining a pH of 12. The process destroys
pathogens, reduces sludge odors, and immobilizes heavy metals. It has also been
approved by the U.S. EPA as an acceptable Process to Further Reduce Pathogens
(PFRP). The resultant soil-like product can be used as a soil conditioner, other
agricultural purposes and landfill cover (32, 48).
CHEMFIX® is a proprietary chemical fixation process patented by ChemFix
Technologies, Inc., Ventura, CA, to stabilize municipal sewage sludges and
industrial wastes (9). This process uses soluble silicates and silicate setting
agents? which are blended with the sludges or wastes to produce a chemically and
physically stable solid material. NATURITE®, which is the end product that
results from the treatment of municipal sewage sludge with the CHEMFIX® process,
is suitable for use as daily landfill cover. The high pH and alkalinity of
NATURITE® also results in effective destruction of pathogens, which classifies
the CHEMFIX® process as a PFRP.
To treat sludges with these or similar fixation processes requires the
construction of sludge processing and curing facilities, possibly at a
significant capital investment. SDPs must be cured and dried to a proper
moisture content (approximately 60%) to avoid workability problems during 1:he
placement of the material onto the working face (IM-4). When at the proper
moisture content, SDPs are reportedly lighter and easier to spread than soil
(26). SDPs are usually applied at a 6-in. (15-cm) layer to provide a cover that
effectively controls vectors and blowing litter. Release of ammonia-like odors,
although usually restricted to the working face, has been reported when these
materials are initially placed onto the working face (26). To both improve
workability and reduce odor problems, SDPs are blended 1:1 with natural soils at
some sites (49). During dry and windy conditions, problems with dust generation
have been reported when SDPs were used as daily cover (IM-4(C-l7)).
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SECTION 6
SITE OPERATION AND MANAGEMENT IMPLICATIONS OF USING
ALTERNATIVE MATERIALS AS DAILY COVER
The feasibility of alternative materials for daily cover is generally
determined by operational, performance and economic comparisons with soil and its
availability. These comparisons may include; impacts on landfill capacity, cover
requirements, operational costs, cover material application considerations,
effectiveness and duration, impact of climatic conditions, potential
environmental impacts, and other site-specific requirements and operational
considerations. This section summarizes key characteristics and features that
should be considered in determining the feasibility of using ADCMs.
6.1 IMPACT ON LANDFILL CAPACITY
The potential savings in landfill capacity has been identified by most
landfill owners/operators as the most important reason for using alternative
cover materials. Not only can ADCMs extend the useful life of landfills, but
they will also allow additional revenues due to space savings that would
otherwise not be possible. Moreover, such savings are independent of the type
of alternative cover material selected. The structural integrity of most
commercially available ADCMs is either destroyed by the placement of wastes the
next operating day, as is the case of foams and spray-ons, or the ADCM is removed
prior to the placement of wastes, e.g., geosynthetics. Consequently, they
effectively occupy negligible landfill space. Although indigenous materials are
typically applied at a similar thickness as soil cover, i.e., 6 in. (15 cm),
these materials would otherwise occupy space within the landfill as waste.
Hence, by being used as a cover material instead, space they would otherwise
occupy is saved.
Landfill capacity savings directly depend on the frequency of alternative
material use as a daily cover in lieu of soil. Although this is influenced by
climatic conditions, it is also dependent on other factors including the
availability of alternative materials or their constituents, the condition and
longevity of material, and the reliability of the application equipment.
Moreover, the value of any saved capacity is directly related to the tipping fees
for waste disposal at the site.
6.2 IMPACT ON SOIL REQUIREMENTS
Use of alternative cover materials decreases requirements for soil as daily
cover, resulting in the conservation of on-site soils or cost savings if daily
cover is acquired from an off-site location. Furthermore, equipment and
personnel costs associated with the movement and placement of soil cover will
also decrease.
Although site-specific evaluations may indicate that any savings realized
by decreasing soil cover may not be very significant or may even be negated by
the costs associated with using an ADCM, there are additional, less tangible but
possibly more •significant benefits, particularly if soil cover material is
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acquired off-site. Decreased soil requirements will also result in less
vehicular traffic, wear and tear on roads (both off-site and on-site), noise, and
dust generation. This can favorably impact environmental quality and relations
with the community in the vicinity of the landfill.
6.3 OPERATIONAL COST CONSIDERATIONS
Determination of potential savings in operational costs associated with the
use of an alternative cover material is usually made by comparison of its cost
with that of using soil as a daily cover at the specific site. Consequently, the
cost of soil cover at the particular site is an important determinant of any
potential cost savings.
In general, operational cost savings are realized when geosynthetics are
used. Geosynthetics are reused, hence, the effective daily cover material cost
is low; less than $0.01/ft ($0.11/m2) per day. They also usually require less
time, equipment and/or personnel to apply than soil cover. However, potential
operational cost savings associated with the use of geosynthetic panels are
greatly dependent on the number of times a particular panel is reused. This is
influenced by climatic conditions, working face preparation and care taken during
the placement and retrieval of panels. Instances have been reported where panels
were destroyed after as little as one or two uses, such as when panels were
frozen to the working face, buried by snow, or damaged beyond repair during
placement or retrieval. This can significantly increase the operational costs
associated with the use of these cover systems. '
The possibility for operational costs savings associated with the use of
foams and spray-ons is more dependent on the cost of soil cover at the particular
site. For illustrative purposes, if soil costs, including equipment costs
associated with the movement and placement of soil cover, are greater than
$3.50/yd ($4.58/m), i.e., $0.065/ft2 ($0.70/m2) for a 6-in. (15-cm) thick soil
layer, savings can be realized when foam or spray-ons are used, based on an
average foam or spray-on cost of $0.06/ft2 ($0.65/m2), including both material and
amortized application equipment costs. This, however, does not consider any
potential site-specific costs related to the use of these products, such as
storage facilities, equipment maintenance, utilities, etc.
It must also be recognized that any potential operational cost savings are
not nearly as significant as the savings that can be realized by conserving
landfill capacity. Consequently, these potential savings are usually not a
determining factor in the selection of a particular ADCM for a site, as other
considerations, such as its ease of application and effectiveness under varying
operational and climatic conditions, may be more important than operational cost
savings.
6.4 APPLICATION CONSIDERATIONS
Ease of application is an important operational factor associated with the
use of ADCMs. As discussed in previous sections, application and placement of
ADCMs can often be accomplished with less equipment and personnel and in less
time than may otherwise be required if a soil cover was used. This can be
particularly significant for sites where adverse weather conditions, e.g., rain
or freezing temperatures, can impact the placement of soil cover to a much
greater extent than such conditions will affect the use of certain ADCMs.
Moreover, since less time may be required to apply or place daily cover, wastes
can continue to be received at the landfill for a longer period of time than
could otherwise be permitted. This can allow greater quantities of wastes to be
disposesd on a daily basis, increasing service and revenues.
There can also be greater flexibility related to the actual placement of
daily coyer when using ADCMs. At landfills with a large working face, e.g,
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greater than 20,000 ft2 (1,860 m2), it is possible to begin the application of
daily cover to one area while continuing to receive wastes in another area of the
working face. This may be especially feasible when using self-propelled
application equipment, since application of the cover material does not require
the use of any landfill equipment and can be accomplished without interfering
*i ,J:,® unloading and compaction of wastes in other areas. Increased
flexibility is also possible when placing or retrieving geosynthetic panels.
Based on the availability of equipment and personnel at a site, some sites may
use several pieces of landfill equipment and all available personnel to place,
anchor, and subsequently retrieve panels in a relatively short period of time
Other sites, based on their particular operational considerations and
requirements, may use only a small crew to manually place the panels
Alternatively, some sites may use specially designed and fabricated ancillary
equipment, such as a lifting bar, reel or roller, to facilitate panel placement
and retrieval. e -. *
6.5 EFFECTIVENESS AS DAILY COVER
Although most ADCMs are able to meet established operational and regulat-ory
criteria for daily cover, distinctions do exist among the various ADCMs with
regard to their ability to control odors and fire, or minimize moisture
infiltration under various climatic and operational conditions. In addition,
site-specific circumstances can impact or influence the relative importance of
specific operational criteria. For.example, for a site that is highly visible
from nearby roads, the ability of an alternative cover material to prevent
blowing litter and provide an .orderly and aesthetically pleasing appearance may
be an important criterium. Similarly, for a site located relatively close to a
residential community, odor and dust control may be of paramount importance.
Furthermore, with few exceptions (e.g., California), performance-based standards
for evaluating the effectiveness of daily cover have not been established.
Consequently, the determination of effectiveness of an alternative material is
often based on relatively subjective judgement by both site operators and
regulators, i.e., comparing the alternative materials' effectiveness to that of
6 in. (15 cm) of compacted soil. These factors can not only influence a
determination of the effectiveness of an ADCM in meeting established criteria at
a particular site, but also make comparisons of ADCMs difficult.
Key features of and distinctions among ADCMs in meeting various operational
criteria for daily cover and areas where further evaluation of these criteria is
warranted are presented below. . .•.j-i-etid. is
6.5.1 Access. Blowing Litter and Odor Control
All ADCMs identified during this investigation are able to control access
to vectors, blowing litter and odors. However, their effectiveness is greatly
dependent on the proper application or placement of the cover to ensure a
complete and continuous cover over the working face. Because of the "sticky"
consistency of nonhardening foams, and of hardening foams and spray-ons when
initially applied,, they readily adhere to the wastes, preventing blowing litter
and discouraging birds from landing and animals from digging. In addition, flies
and other insects become trapped upon contact. Hardening foams and spray-ons
subsequently form a resilient cover that prevents access to the wastes by
vectors. Geosynthetics completely cover the wastes, thereby preventing blowing
litter. They are also designed to be tear- and puncture-resistant, thereby
denying access to vectors, e.g., pecking and tearing by birds and animals.
Indigenous materials also effectively control blowing litter and access to
vectors if placed onto the working face at a sufficient thickness and consistency
to completely contain and cover the wastes. ;
Although it is generally acknowledged that ADCMs, like soil cover, are able
to contain odors emanating from the working face, the actual effectiveness in
controlling odors and other emissions is difficult to assess. Determinations of
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the effectiveness of ADCMs in controlling odors and other emissions are usually
based on subjective judgement. Moreover, only limited studies have been
performed to determine the effectiveness of various foams, spray-ons, and
geosynthetics in providing such control (21, 22, 38). Therefore, further
evaluations to better quantify the effectiveness of various ADCMs in controlling
odor and other emissions from the working face may be warranted. However!
investigations initially should be performed to determine the actual requirements
for such controls, based on health, environmental and aesthetic considerations.
Once these requirements are determined, performance standards for odor and of her
selected emissions could be established. Furthermore, it must be recognized that
limits for any specific levels of odors or other emissions from the working face
at landfills may be difficult, since the release of odors and other emissions are
not necessarily limited to this area.
6.5.2 Fire Control
The ability of daily cover to lessen the risk and spread of fires is
primarily dependent on the combustibility of the material and how effectively the
movement of atmospheric oxygen to the working face can be controlled. The
ability of a cover material to provide a barrier to the movement of fires within
landfill cells is also one criterium for daily cover. The combustibility of
ADCMs varies among the different products: some ADCMs are noncombustible, e o
nonhardening foams; some contain combustible constituents, e.g., spray-ons but
are applied as an aqueous slurry/emulsion which greatly reduces their
combustibility; and other products, although combustible, are rated as
nonflammable and self-extinguishing, e.g., SaniFoam™, Aqua-Shed1". In addition
their effectiveness in controlling movement of atmospheric oxygen to the working
face and thereby support combustion is dependent on proper application to ensure
complete and continuous coverage, e.g., foam and spray-ons, or the permeability
of the material, e.g., geosynthetics and indigenous materials. Furthermore
since foams and spray-ons are mechanically destroyed by subsequent placement of
wastes, and geosynthetics are removed from the working face each day little
barrier to the spread of fires within the landfill is provided when these
materials are used as daily cover and then destroyed or removed. Combustible
indigenous materials also do not form any barrier to the spread of fire while
noncombustible indigenous materials can form a barrier that is comparable to that
provided by soil cover.
Since some ADCMs are combustible, the development of combustibility
standards for daily cover materials may be warranted to ensure that the use of
alternative materials does not result in an increased risk of fires at landfills
Combustibility standards for daily cover materials, however, must recognize the
relative significance of the combustibility of the cover material in comparison
to other procedures and controls that are typically instituted by landfill
operators to prevent fires from occurring, such as routine checks for "hot" locids
and quickly extinguishing fires if they do occur. Furthermore, the requirement
, r^Hy cover to be able to Provide a barrier to the spread of fires within a
landfill should be assessed both in consideration of other operational benefits
that can be realized by not having such intervening layers within the landfill
such as more effective leachate and gas management, as well as the actual
effectiveness of such a barrier, e.g., a 6-in. (15-cm) layer of soil, to the
spread of fires.
6.5.3 Minimization of Moisture Infiltration
j
wi Jc°1reduce the infiltration of moisture into the landfill, ADCMs must be
able to shed rainwater from the working face. With the exception of nonhardening
foams and certain indigenous materials, such as shredded tires and green waste!
ADCMs are able to reduce infiltration. Their effectiveness, however, depends on
proper application of the cover to obtain complete and continuous coverage, as
in the case of hardening foams and spray-ons, or the composition of the material,
in the case of geosynthetics and indigenous materials. Moreover, the importance
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placed on an ADCM's ability to minimize infiltration should be based on site
IwteSCanSdn«fnftS:i10*8' includi.n9 Choice of leachate management and control
systems and rainfall frequency, intensity and duration.
6.5.4 Leachate and Gas Control
The use of commercially available ADCMs enhances leachate and «««
management by not creating intervening layers within the lanafSf that coSd
otherwise impede controlled movement. Materials like foams and spray-ons "~
mechanically destroyed by subsequent placement of wastes, wherels geolynSe
are removed from the working face. When an indigenous material is^sed^as d
t
to distribute moisture throughout the landfill and to a«elera?e^S^mlc?obial
degradation of wastes, elimination of intervening layers will significant
employed, and the type of
desired and/or required.
6.5.5 Dust Control
Use of foams, spray-ons and geosynthetics all significantlv reduce t-h
^^
(e.g., shredded tires) during or subsequent to placement onto8 the wlrking^fa""!?
6.6 DURATION OF COVER ;
Another consideration in determining the feasibility of an alternative
r^lvaclvir 1Theh?mPeri°d °f,tlr fc?at the material wiliyremain effective Is
«* vCv/S? t , Jw importance to be placed on the duration, or effective life
of an ADCM should be assessed in consideration of both operational and regulatory
*'*^£^^~^^^*^^ requirements may ^e ^S
ot time and under what conditions a
rnlrL ° me an "nder what conditons a
particular alternative material may actually be used as a daily cover, regardless
lace!" g XS ^^ t0 remaln 6f fSCtiVe aS a COVer once aPPlied to'the9woS!ng
°f ^e ^ foamS and sPraY-°ns can remain as effective cover
nH • particular product, thickness of application and climatic
conditions. These times can range from 15 hr up to 7 days for nonhardenina and
"* £tO- m°re than a week fc° -veral months Ior°spra?onsg( lee
^ = A<11t^°?gh ^ Ien9th of time th*t a geosynthetic can be used as an effective
cover will depend on the composition of the material, of greater significance is
flcenUtheerca°re t^SS H^ th^material i- P^ced and removed fro* the ^working
s^te: ^T^e^^et^^^^^^^
STS'JS*^ S°me Pr°dUCt
110
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6.7 IMPACT OF CLIMATIC CONDITIONS
Climatic conditions also need to be considered in determining the
feasibility of using an ADCM at a specific site. Of particular interest to site
operators is the potential impact of various conditions of rainfall, temperature
and wind on how often the alternative material can be used as daily cover, the
ability to apply or place, destroy or remove the cover material, and its
subsequent effectiveness if reused as a daily cover under such conditions.
6.7.1 Foams and Sprav-ons '
Rain and wind can impact on the application of foams and spray-ons (See
Tables 2 and 6). Moderate to heavy rain can wash out nonhardening foams and
hardening foams, and spray-ons also cannot be applied during such rain events.
Howevesr, hardening foams and spray-ons can withstand moderate and heavy rain and
remain effective as a daily cover once they harden, which usually occurs within
1 to 2 hrs. Although high winds may impact on the application of foams and
spray-ons, operational adjustments can usually be made to compensate for this
effect. Once applied, foams and spray-ons adhere to the wastes and are not prone
to being blown off the working face.
6.7.2 Geosynthetics
Wind is the predominant climatic condition that affects the use and
placement of geosynthetics, although rain and freezing conditions may also impact
the use of certain materials, e.g., nonwoven materials. In addition, although
it does not impact the effectiveness as a daily cover, the possibility of snow
may significantly affect the useful life of geosynthetics (See Tables 10A, 10B
and IOC). '
Wind affects both the placement of panels and requirements, for anchoring.
Under windy conditions, more time and additional labor may be required to place
the panels, due to increased difficulties in handling and anchoring panels. With
very high winds, it may be unsafe and impractical to attempt to use geosynthetic
panels. >
Although rain will not significantly impact the effectiveness of
geosynthetics as a daily cover, i.e, they are not deteriorated by rain events and
reduce infiltration by shedding water from the working face, some products, e.g.,
nonwoven materials, absorb moisture, become heavier and are more difficult to
handle under such conditions. Due to their increased weight, such panels are
also more prone to snag and tear, decreasing their useful life.
With some geosynthetics, difficulties in handling, placement and retrieval
may be encountered during freezing conditions. Products that may absorb moisture
can freeze either together or onto the soil while being stored near the working
face. Panels can also freeze to the working face if the material has absorbed
moisture or if there is a high moisture content in the wastes being covered and
freezing conditions develop after the panel has been placed. Attempting to use
or retrieve panels under these conditions will not only require more time and
effort, but will also increase the risk of damage to the panel. To prevent loss
or damage to panels, many sites prefer not to use panels if there is a
possibility of snow.
6.7.3 Indigenous Materials
Rain and freezing temperatures are the predominant climatic conditions that
impact the use and performance of indigenous materials, although these impacts
will vary based on the physical characteristics of the material (See Tables 13A
and 13B). Such conditions can cause operational problems related to loading,
transport and placement onto the working face, e.g., the material's moisture
content may be too high to permit proper handling or, if frozen, it cannot be
111
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excavated or spread onto the working face. Depending upon the permeability of
the material, moisture may also infiltrate into the landfill, e.g., shredded
tires. Under dry weather conditions, dust generation may be of concern with
soil-like materials, or the risk of fire may increase if the material is
combustible, e.g., green waste.
6.7.4 Operational Alternatives during Adverse Climatic Conditions
When ADCMs are not able to be used due to adverse climatic conditions, most
sites revert to using soil cover. This practice, however, negates some principal
benefits associated with the use of alternative materials, such as savings in
landfill capacity and elimination of barriers which can impede effective leachate
and gas management. As discussed above, climatic impacts differ among various
types of ADCMs. For example, while foams and spray-ons may not be able to be
applied during heavy rainfall, various geosynthetics could effectively be used
under such conditions. Alternatively, whereas the use of geosynthetics may not
be feasible under freezing conditions or the possibility of snow, foams or spray-
ons can be effectively used. Hence, landfill operators should consider the
operational and economic feasibility of using different types of alternative
materials under various climatic conditions in order to maximize the benefits
associated with the use of these materials.
6.8 POTENTIAL IMPACT ON LEACHATES AND LANDFILL ENVIRONMENT
Although foam and spray-on covers are mechanically destroyed with the
placement of wastes on subsequent days, these materials remain within the
landfill and their leachable constituents may affect the composition of leachates
and their subsequent treatment, or otherwise impact the landfill environment.
Constituents leached from indigenous materials used as daily cover can similarly
affect leachate composition or impact the landfill environment. Although
analytical methodologies, such as the Toxicity Characteristic Leaching Procedure
(TCLP), can be used to assess the potential for leaching toxic constituents from
these materials, such procedures are primarily intended to determine the presence
of and to characterize hazardous materials and not to assess the long-term
impacts on leachates and the landfill environment. Because natural processes of
stabilization within the landfill normally occur over an extended period of time,
and many alternative cover , materials have been available and used for a
relatively short period of time, potential long-term impacts of constituents
leached from alternative cover materials on leachates, landfill stabilization and
the environment, although generally considered to be minimal, may need to be
established.
6.9 SITE REQUIREMENTS AND OPERATIONAL CONSIDERATIONS
Site requirements and operational considerations that may impact the
feasibility of using an ADCM at a specific site include the availability of
alternative materials or their constituents, requirements for application
equipment, availability of storage facilities and utilities at the site, working
face preparation, and personnel considerations.
6.9.1 Availability of Materials
Both foam and spray-on ADCMs involve the use of specially formulated liquid
concentrates or dry materials provided by the manufacturer of the product. To
effectively and efficiently use the product as an daily cover, site operators
must ensure that the manufacturer can provide sufficient quantities of the
materials on a regular and continuing basis.
Geosynthetic panels are usually fabricated to site-specific requirements
by the manufacturer, although some sites purchase the material and fabricate
their own panels on site. To ensure uninterrupted use of panels as daily cover,
there must be a sufficient number of panels available at the site so that damaged
or destroyed panels can be readily replaced.
112
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The feasibility of using indigenous materials as daily cover depends on the
local availability of sufficient quantities of material on a regular basis. This
is particularly important to justify any capital investments and additional
operational costs that may be associated with the use of the indigenous material,
e.g., shredder.
6.9.2 Ecruipment Requirements
Foams and spray-ons are applied to the working face using equipment
specifically designed by the manufacturer for the application of that particular
product. Site operators must not only consider the capital investment necessary
to acquire this equipment, but also requirements for routine maintenance and
specialized maintenance and repairs by the manufacturer, during the life of the
equipment. Because many products have been available for only a relatively short
period of time (2-3 yr), limited information is available on amortized costs of
application equipment and maintenance and operational costs associated with the
use of such equipment over an extended period of time. Moreover, operators must
consider the operational, regulatory and economic implications and consequences
associated with the unavailability of equipment due to breakdown or routine
maintenance requirements.
Geosynthetic panels are typically placed manually or by using standard
landfill equipment already available at the site. Hence, the acquisition of
specicilized application equipment is usually not required. Although some sites
have designed and fabricated ancillary equipment such as lifting bars, reels and
rollers to facilitate placement and retrieval of panels, use of such equipment
is optional. Furthermore, the cost of such equipment, which averages $1,000-
2,000, is significantly less than the cost of equipment required to apply foams
or spray-on products.
Indigenous materials are usually transported to the landfill and placed
onto the working face with equipment similar to that used to transport and place
soil cover, e.g., trucks and dozers. However, with some indigenous materials,
special equipment (i.e., a shredder) may be required on-site to process materiails
such as tires and green waste prior to use as an ADCM.
6-9.3 Availability of Storage Facilities and Utilities
The materials used in the formulation of foams or spray-ons may have shelf-
life and/or storage temperature restrictions, requiring an appropriate storage
facility. Since these products are applied with specially designed equipment,
appropriate storage facilities may also be required for this equipment during
cold weather, unless the equipment is freeze-protected or properly serviced to
permit outside storage. Also, since most of these products are diluted or mixed
with water prior to use, a pressurized water source or water tank/truck must be
available on-site.
Geosynthetic panels do not require any storage facilities since they are
usually stored near the working face. Also, on-site storage facilities or
utilities are usually not required for indigenous materials, unless these are
required for special equipment to process certain materials prior to use as daily
cover. >
6.9.4 Working Face Preparation
Working face preparation prior to the application of daily cover affects
the amount of material needed to provide effective cover, the time and effort
required to place the cover, and costs, regardless of the cover material used.
However, the importance of a smooth, well-compacted working face is usually
greater for alternative materials, and can significantly affect both material
cost and application time.
113
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Foams can provide an effective cover at thicknesses of as little as 2 to
3 in. (5 to 7.5 cm). However, if additional foam must be applied to ensure
proper coverage of the waste because the working face is not smooth or compacted,
its cost and the time required to apply the cover will be increased.
When using spray-ons, which are applied as a relatively thin layer compared
to foams, the smoothness of the working face is of even greater importance. If
the working face is not smooth or well compacted, the total exposed surface area
of wastes that must be covered increases significantly. This directly affects
the amount of slurry/emulsion that must be applied to the working face and,
consequently, its costs. The time required to apply an effective cover will
similarly increase due to both the need to cover a larger total surface area, and
the necessity to reposition the application equipment to ensure that "shadows"
are effectively covered.
Although working face preparation has a lesser impact on the use of
geosynthetics, it can affect; both the time required to place panels and the
duration or effective life of the panel. When placed on the working face, panels
will effectively cover the wastes regardless of its smoothness or compaction.
However, a smooth working face will result in less snagging and tearing of the
panel, thereby reducing the time required to place and retrieve panels and also
extending their useful life.
6.9.5 Personnel Considerations
Landfill operators must also consider the operational skills that are
required to properly prepare and apply alternative cover materials, as well as
possible occupational health and safety concerns that may be associated with the
use of these materials or their constituents. Since foam or spray-on application
equipment is specifically designed for these products, site managers must ensure
that equipment operators are provided adequate training and possess the necessary
skills to properly and safely.operate the equipment and effectively apply cover
material. In addition, because the materials used in the formulation of foams
and spray-ons are not normally used at landfills, it may be necessary to provide
special training to ensure that personnel are familiar with proper procedures for
handling these materials and/or to provide personal equipment, e.g., gloves and
goggles. ' Also, the placement of geosynthetic panels usually requires personnel
to walk across the working face in order to place panels or to provide anchoring.
This increases exposure to the wastes and the risk of injury. Furthermore,
during the retrieval of panels from the working face, personnel can be exposed
to thes wastes and to releases of odors and other emissions from the wastes.
114
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SECTION 7
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations regarding the use and
performance of alternative daily cover materials are based on evaluation of the
information presented in this report.
7.1 CONCLUSIONS
Use of alternative materials for daily cover in lieu of soil can result in
operational, performance, environmental and economic benefits at municipal solid
waste landfills. These include ease of application, improved effectiveness in
meeting site operational and regulatory requirements, savings in landJrill
capacity, decreased requirements for soil, and more effective leachate and gas
management.
Most alternative daily cover materials are able to meet established
criteria for daily cover under various operational and climatic conditions. In
addition, although dependent on site specificity and the particular alternative
material used, certain materials are more effective than soil as a daily cover,
especially with respect to control of vector access, blowing litter and odor, and
the minimization of moisture infiltration. :
The use of alternative cover materials essentially eliminates intervening
barriers within the landfill and thereby facilitates the controlled movement and
collection of leachates and gases for ultimate disposition without incurring
adverse environmental effects associated with less predictable lateral leachate
and gas migration.
The effectiveness of ADCMs is dependent on proper working face preparation
and equipment operator proficiency during application or placement of the cover
material. Climatic conditions and other site-specific considerations will also
affect the choice of ADCM, its method of application and effectiveness as daily
cover. Therefore, appropriate understanding of these factors is an important
consideration in selecting and applying ADCMs.
Evaluation of the effectiveness of ADCMs in meeting operational and
regu]atory criteria for daily cover is generally based on subjective comparisons
with soil cover. Therefore, this lack of consensus performance-based standards
for various operational and climatic conditions limits selection and
determination of relative effectiveness.
Since many alternative cover materials have only been available and used
for relatively short periods of time, some questions remain concerning potential
long-term impacts of leachable constituents and/or their final disposition within
the landfill disposal context.
There is currently limited information and operational experience related
to the longevity of foam and spray-on application equipment, amortized equipment
costs and the operational and maintenance costs over extended periods of time.
115
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Hence, it is difficult to determine long-term equipment operation and maintenance
costs related to the use of these products.
7.2 RECOMMENDATIONS
Because of the potential for enhancing operational, performance and
environmental aspects related to the management of municipal solid waste
landfills, as well as decreasing space requirements and conserving site
resources, the use of ADCMs as alternative cover options should be considered
during the design, construction and operational phases of municipal landfills.
Performance-based standards should be established to permit more objective
evaluations of the short-term and long-term effectiveness and suitability of
alternative materials for use as daily cover at municipal landfills. Such
standards may be particularly warranted for control of odors and other emissions,
for health, environmental and aesthetic considerations, and for the restriction
of the spread of fires at landfills. Barrier to the spread of fires within the
landfill should also be evaluated relative to the need to improve and control
leachate and gas" migration and the associated benefit elimination of such
intervening barriers would provide.
To ensure proper and effective use of alternative cover materials,
coordination between manufacturers of ADCMs and the regulatory and user
communities is recommended to ensure appropriate use of ADCMs and to provide
training and possible certification programs.
Opportunities to further improve the performance as well as the
environmental and operational acceptability of ADCMs should be pursued. These
include increasing the use of recyclable materials in the formulation or
fabrication of ADCMs; use of leachate, in lieu of water, in the preparation of
aqueous foams and spray-ons; reducing the combustibility of geosynthetics; and
modifications to methods of application or placement. In addition, landfill
operators should consider the operational and economic feasibility of using
different types of alternative cover materials under various climatic conditions
in order to maximize the potential benefits. The potential for long-term impacts
on leachate composition and subsequent treatment, landfill stabilization and the
environment from constituents of alternative cover materials should also be
assessed. ,
To facilitate greater use of ADCMs, regulatory agencies should evaluate the
feasibility of granting State-wide approval for the use of specific-ADCMs, based
on pertinent performance data and/or selected site-specific demonstrations.
116
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1
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1.
2.
3.
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5.
6.
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9.
10.
11.
12.
13.
14.
Anon. (1991) Landfill Uses Old Newspapers as Daily Cover Material.
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Florence, SC.
Barry, G.F. (1990) FabriSoil" - An Alternative for Daily Cover at Solid
Waste Landfills. Paper presented at Second Annual Waste Equipment and
Recycling Conference and Exhibition, Rosemont, IL.
Bay Hill Marketing. (Acquisition date: 1992) Land-Cover Formula 480
Product Literature, Altamonte Springs, FL.
California Code of Regulations. (1990) Title 14 - California Waste
Management Board, Para. 17225.16, 17225.17, 17682, and 17683.
Carry, c. (1991) Sanitation District of Los Angles County Green Waste
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Landfills, Los Angles County Sanitation District, Whittier, CA.
Carson, D.A. (1991) Municipal Solid Waste Landfill Daily Cover
Alternatives. Proceedings of the 5th GRI Seminar on Geosynthetics and
Filtration, Drainage and Erosion Control, Drexel Univ., Philadelphia, PA.
CHEMFIX Technologies, Inc.
Applications, Metaire, LA.
(1989) CHEMFIX® Product in Landfill
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Literature, Exton, PA.
Cieslik, M.J., Stecker, P.P., and Marsden, M.A. (1986) Use of Synthetic
Daily Landfill Cover. Proceedings of Ninth Annual Madison Waste
Conference, University of Wisconsin-Madison, Madison, WI.
CORMIER Textiles Products, Inc. (Acquisition date: 1992) CORMIER Product
Literature, Sanford, ME.
COVERTECH Fabrication, Inc. (Acquisition date: 1992) COVERTECH C-440
Product Literature, Rexdale, Ontario.
Donohue & Associates. (1989) Inspection Report on Application of Fojun
Material as Alternative Daily Cover, G.R.O.W.S., Inc. Landfill, Falls
Township, PA.
117
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15. EEC Environmental, Inc. (1991) Draft Interim Final Report, Six Month
Demonstration of Daily Cover at Cape May County Municipal Utilities
Authority Sanitary Landfill, Woodbine, NJ.
16. Environmental Network. (1991) Alternative Daily Cover Material for
Landfill Use, Henniker, NH.
17. Exxon Chemical Company. (Acquisition dates 1992) Typar® Daily Landfill
Cover Product Literature, Old Hickory, TN.
18. Federal Register. (1991) 40 CFR Part 258. Criteria for Municipal Solid
Waste Landfills, Para. 258.21, Washington, D.C.
19. Florida Department of Environmental Regulation. (1990) Solid Waste
Management Facilities - Sanitary Landfill Criteria, Para. 17-701.50.
20. Fluid Systems, Inc. (Acquisition date: 1992) SaniCover™ Product
Literature, Cincinnati, OH.
21. Hull & Associates. (1991) Report of Investigations Concerning the Relative
Environmental Impacts of the Use of ConCover® and ConCover® with RainPlus,
Toledo, OH.
22. Kittle, P. and Schmidt, C.E. (1993) Comparison of Long Duration Foam,
Synthetic Tarpaulins, Geotextiles, and Soil as Subtitle D Compliant Daily
Cover Materials for Sanitary Landfills. Paper presented at the Solid
Waste Management Association Waste Tech '93 Conference, Marina Del Roy,
CA.
23. Kmet, P. (1983) Evaluation of the Use of SaniBlanket™ to replace Daily
Cover for Landfills in Wisconsin, Wisconsin Department of Natural
Resources, Madison, WI.
24. Maguin, S. (1991) Green Waste Recovery Program, Los Angles County
Sanitation District, Whittier, CA.
25. Massachusetts Department of Environmental Protection. (1990) Chapter 310
CMR 19.000, Solid Waste Management Facility Regulations, Para. 19.062,
19.105, and 19.130. ;
26. Middlesex County Utilities Authority. (1991) Status Report - Application
of Sludge Derived Product at Edgeboro Landfill, Sayreville, NJ.
27. Midwest Environmental Consultants, Inc. (1989) Report on the Effectiveness
of the ConCover® Material at the Huron County Landfill, Toledo, OH.
28. Midwest Environmental Consultants, Inc. (1991) Report on the Effectiveness
of the ConCover® Material at the Wood County Landfill (2nd trail period),
Toledo, OH.
29. Newastecon, Inc. (Acquisition date: 1992) ConCover® Product Literature,
Perrysburg, OH. ;
30. Newastecon, Inc. (Acquisition date: 1992) ConCover® Site Certification
Procedure, Perrysburg, OH.
31. New York Department of Environmental Conservation. (1991) 6NYCRR, Part
360, Solid Waste Management Facilities, Section 360-2.17.
32. N-Viro Energy Systems Ltd. (Acquisition date: 1992) N-Viro Product
Literature, Toledo, OH.
118 ;
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33. Pennsylvania Bulletin. (1992) Vol. 22, No. 41, Environmental Quality
Board, Solid Waste Management Regulations, Para. 273.232. '
34. Pennsylvania Department of Environmental Resources. (1991) Modification to
Solid Waste and/or Processing Permit, Grand Central Sanitary Landfill, Pen
Argyl, PA. Bureau of Waste Management, Wilkes-Barre Regional Office,
Wilkes-Barre, PA.
35. Phillips Fibers Corp. (Acquisition date: 1992) FabriSoil™ Product
Literature, Greenville, SC.
36. Pohland, F.G. (1983) The Use of Plastic Foam as a Cover Material During
Landfilling of Solid Wastes, Report E-20-HOI, Georgia Institute of
Technology, Atlanta, GA.
37. Polyfelt, Inc. (Acquisition date: 1992) Polyfelt X0010 Daily: Cover Product
Literature, Evergreen, AL.
38. Polytechnica. (1990) Evaluation of TerraFoam™ for Suppressing Volatile
Hydrocarbon Vapors, Wallace, CA.
39. PRC Environmental Management, Inc. (1992) Alternative Daily Cover
Materials For Municipal Solid Waste Landfills, McClean, VA.
40o Querio, A.J. and Lundell, C.M. (1991) Geosynthetic Use as Daily Cover.
Proceedings of the 5th GRI Seminar on Geosynthetics and Filtration,
Drainage and Erosion Control, Drexel Univ., Philadelphia, PA.
41. Reef Industries, Inc. (1992) Griffolyn® Product Literature, Houston, TX.
42. RUSMAR, Inc. (1992) RUSMAR® Foam Technology Product Literature, West
Chester, PA.
43. Spleen, T. (1988) Daily Cover Is Where You Find It. Waste Age. 19, 125-
126.
44. 3M Industrial Chemical Products Division. (1989) SaniFoam™ Synthetic Dciily
Cover Product Literature, St. Paul, MN.
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Site Evaluations, and Laboratory Analysis Performed on SaniFoam™ Synthestic
Daily Cover by Independent Laboratories, Universities, and Consulting
Firms, St. Paul, MN.
46. Tucker, O.K. (1992) An Evaluation of Alternative Daily Cover Materials in
Sanitary Landfills. Senior Project, Allegheny College, Meadville, PA.
47. URS Consultants. (1990) Evaluation of 3M SaniFoam™ Synthetic Daily Cover
System, North Royalton Road Landfill, Cleveland, OH.
48. VFL Technology Corp. (Acquisition date: 1992) Sludge-based Soils: The Cost
Saving Alternative for Sludge Disposal, Malvern, PA.
49. Williamson, C. (Acquisition date: 1992) N-Viro Soil and Landfill - An
Economic Opportunity. Carey Technologies, Lexington, KY.
50. Wire Rope Specialists. (Acquisition date: 1992) Airspace Savers™ Daily
Cover Product Literature, Baton rouge, LA.
51. Woods, R. (1992) Building a Better Liner System. Waste Age. 23, 26-32.
119
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APPENDIX A
MANUFACTURERS OF COMMERCIALLY AVAILABLE
ALTERNATIVE DAILY COVER MATERIALS WITH 1992 CONTACTS
FOAM PRODUCTS
RUSMAR®
RUSMAR, Inc.
216 Garfield Street
West Chester, PA 19380
(215) 436-4314
Contact: Paul Kittle
SaniFoam™
3M Industrial Chemical Products Division
3M Center Building 223-6S-04
St. Paul, MN 55144
(612) 736-4236
Contact: Bruce Spoo
TerraFoam'"
National Foam, Inc., Environmental Products Division
(formerly Chubb Environmental Security, Inc.)
150 Gordon Drive
Exton, PA 19341
(215) 363-1400
Contact: Scott Biddle/William Swayne
TopCoat*
Central Fiber Corporation
4814 Fiber Lane Road
Wellsville, KS 66092
(800) 654-6117
Contact: Dung Trieu
SPRAY-ON PRODUCTS
ConCover®
New Waste Concepts, Inc.
(formerly Newastecon, Inc.)
7401 Fremont Pike
Perryburg, OH 43522
(419) 872-8160
Contact: Tim Johnson
; (continued)
120
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Land-Cover Formula 480
Enviro Group, Inc.
913 N. Drexel Ave.
Indianapolis, ID 46201
(419) 872-8160
Contact: Jerry Backer
Bay Hill Marketing, Inc.
913 State Road 434, Suite 1201
Altamonte Springs, FL 32714
(407) 774-6952
Contact: Obrian Norris
Posi-Shell1"
Landfill Service Corporation
2183 Pennsylvania Avenue
Apalachin, NY 13732
(607) 625-3050
Contact: David Hansen/Bruce Super
GEOSYNTHETIC PRODUCTS
Airspace Saver™ Daily Cover
Wire Rope Specialists
P.O. Box 77757
Baton Rouge, LA 70879
(8QO) 673-1570
Contact: Marlou Yarborough
Aqua-Shed™
Aqua-Shed Manufacturing Corporation
3231 Bryson Drive '.
Florence, SC 29501
(803) 661-7444
Contact: Fritz Kramer
COVERTECH C-440
COVERTECH Fabricating, Inc.
52 Carrier Drive, Unit 7
Rexdale, Ontario M9W 5S5 Canada
(416) 798-1340
Contact: John Starr
Cormier Textile Products, Inc.
P.O. Box 1718
Sanford, ME 04073
(207) 490-2400
Contact: Ken Cormier
(continued)
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FabriSoil®
Phillips Fibers Corporation
P.O. Box 66
Greenville, SC 29602
(803) 242-6600
Contacts Richard Berry
Griftolvn*
Reef Industries, Inc.
P.O. Box 75250 :
Houston, TX 77275
(800) 231-6074
Contact: Mike McElhany
Polvifelt X0010 fDailv Coverfelt)
Polyfelt, Inc.
P.O. Box 727
200 Miller T. Sellers Drive
Evergreen, KL 36421
(205) 578-4756 or (312) 477-9228
Contact: Dave Colosimo
SaniCover™
Fluid Systemsj Inc.
32 Triangle Park Drive, Suite 3201
Cincinnati, OH 45246
(513) 771-5656
Contact: Gregory Scales
Typar®
Exxon Chemical Company
70 Old Hickory Blvd.
P.O. Box 511
Old Hickory, TN 37138
(800) 321-6271
Contact: William Hawkins
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APPENDIX B.
SUMMARY OF INFORMATION REQUESTED FROM MANUFACTURERS
AND LANDFILL OWNERS/OPERATORS
Table B-l.
SUMMARY OF 1992 INFORMATION REQUESTED FROM MANUFACTURERS
OF ALTERNATIVE DAILY COVER MATERIALS
1. Name and/or trademark of product. i
2. Description and composition.
- Does it contain recyclable materials?
- Does it contain leachable hazardous constituents?
Is it combustible?
3. Requirements for special equipment to apply.
4. Shelf-life restrictions or storage requirements
for constituents and/or application equipment.
5. For geosynthetics: typical panels sizes and any special
modifications made to the material for use as an daily
cover.
6. Costs
- Materials
- Equipment required for application
- Optional equipment that can be used to facilitate
application.
(Continued)
123
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1
fable B-2.
SUMMARY OF 1992 INFORMATION REQUESTED FROM LANDFILL OWNERS/OPERATORS
ON THE USE AND PERFORMANCE OF ALTERNATIVE DAILY COVER MATERIALS.
1. General.
a. Name of product used.
b. Regulatory requirements and/or restrictions.
.c. Primary benefits associated with the use of ADCMs
- Increases landfill capacity/extends useful life.
- Easier to apply.
- Requires less time, equipment and/or manpower. !
- Less expensive.
- More effective than soils.
d. Extent of ADCM use (How long and under what conditions).
e. Operational requirements and/or restrictions (e.g., working
face size or preparation) for use of the ADCM.
f. Operator acceptance. •
2. Application.
a. Method(s) of application.
- Type of equipment required.
- Material and equipment preparation requirements.
- Alternative methods of application, if any.
b. Manpower Requirements.
- Number of operators/laborers required.
- Time required for preparation and/or application.
- Special skill requirements.
- Occupational health and safety considerations.
c. Foams/spray-ons application: ]
- Thickness applied.
- Application rate.
- Curing time, if applicable.
ct. Geosynthetics application:
- Size of panel(s) used.
- Number of times reused.
(Continued)
124
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Table B-2 (Conf d)
Impact of Climatic Conditions.
a. Rain.
b. Wind.
c. Temperature.
d. Snow.
Effectiveness as a Daily Cover.
a. Vector access control
b. Fire control (combustibility/air intrusion/barrier wall)
c. Litter control.
d. Odor and other air emissions control.
e. Water infiltration control.
f. Dust control.
g. Leachate and gas migration control.
h. Aesthetic considerations. :
Costs.
a. Materials.
b. Equipment (required and/or optional).
c. Other (e.g., storage facilities).
125
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Comments
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Operational: Has been used for 18 mo. Equipment applies a 6-in. (15-cm) layer of
foam as required by permit. Foam can be applied during light to moderate rainfall,
but is not used if heavy rains (e.g., thunderstorms) are forecast. Can last 72 hr or
more, but regulators limit to overnight use. Concentrate/foaming unit stored in shed
in cold weather.
Stated Benefits: Saves landfill capacity (estimated at 5-6%).
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Operational: Site demonstration. Applied 6-in. (15-cm) layer of foam. Foam
provides complete and continuous coverage of wastes. "Monitor" nozzle was used
to cover large protrusions. Refilling of unit required 15-20 min. The foam's sticky
consistency discourages birds and animals and traps insects. Provides good odor
control and an aesthetically pleasing appearance. Foam can withstand moderate rain
events, including thunderstorms.
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Operational: Product has been available since 1990. Protein-based foam is
designed to last 72 hr. Concentrate shelf-life is at least 6 mo. Application unit is
designed to be multi-functional. Units can be designed to meet site-specific
requirements (self-propelled, truck-mounted or towed). Preparation takes 30 min
and application of a 6-in. (15-cm) thick layer to a 10,000 ft2 (930 m2) working face
requires 30-40 min (not including refilling time which varies with sites).
Modifications in formulation of foam and method of application are being evaluated.
Material costs averages $0.12/fi? ($1.29/m2) for 6-in. (l5-cm)Jayer. Equipment „
costs ranged from $70,000 (truck-mounted) to $350,000 for self-propelled unit.
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Operational: Has been used since 1990. Uses multiple 50 by 50 ft (15.3 by 15.3
m) panels overlapping their edges. A panel requires two to three person 5-10 min
to place. Also has used "tow bar" to place 100 by 100 ft (30.5 by 30.5 m) panel by
dragging it onto the working face with landfill equipment (average time 20-30 min).
Currently uses on-site fabricated lifting bar (costs $2,000) with excavator to
place/retrieve panels. With help of two-person crew, can place 12 panels in 1-1.25
hr. Panels can be placed in winds of 20 mph (32 km/hr) without difficulty. They
are anchored if high winds are expected. Anchoring takes 15-20 min. Also uses
panels with 5/8-in. (1.6-cm) chain sewn into hem, which effectively anchors panels
in winds of 35 mph (56 km/hr). No problems using panels during rain or freezing
temperatures. Cover sheds all rainwater. Birds do not land on it. It is too heavy, .
especially with "chain-in-hem" for animal access around edges. Panels are very
durable; they last 10-12 mo, some 18 mo.
Stated Benefits: Saves landfill capacity (up to 20%) and is easier to apply and less
expensive than soil (saves $350/day in soil and operational costs).
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Operational: Was used for 1 mo demonstration utilizing lifting bar and excavator
and two-person crew to place 50 by 50 ft (15.3 by 15.3 m) panels with "chain-in-
hem". Lifting bar was custom-fabricated for $4,000. Was able to cover 10,000 ft2
(930 m2) in 30 min. Panel placement required that crew walk on working face.
Panels were retrieved the next operating day while it was still dark. Flashers were
placed on the end of the lifting bar as a safety precaution. Was able to retrieve
panels with lifting bar after 2- to 3- in. (5- to 7.5-cm) snowfall. No operational
problems were reported during freezing weather, but can become slippery to walk
on. Panels completely covered wastes and were very durable. It was too heavy
(Cont'd)
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Operational: Material has been available as daily cover
60 by 150 ft (18.3 by 45.7 m) and weigh approximately
usually placed by three- to four:person crew in 15-20 mi
equipment. Anchoring is done in a grid pattern at 20-ft
durable and woven, preventing punctures and tearing by
not like to land on the cover. Panels typically lasts 2-3 i
for 6 mo. With extended use, "flutter", caused by wind
can weaken material. This, however, has not been repoi
as daily cover. Panels are also available with a fire-reta
WP-640 is $ 0.085/ft2 ($0.91/m2) and for WP-1440 $ 0.
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Operational: Has used both SaniCover™ 150 and 750 for 17 mn Panels 75 In
ft (22.9 by 24.4 m) are placed by using two compactors and two-person crew.
Orienting the leading edge into a 5 mph (8 km/hr) wind helps lift panel, reduce
drag and facilitates placement. Panel placement typically requires 15-20 min.
Tires are used as anchors at 20-30 ft (6.1-9.1 m) intervals. If not anchored,
SaniCover™ 250 can be blown off by 5-10 mph (8-16 km/hr) winds. Size of
working face must be controlled to ensure panels can completely cover the was
SaniCover™ 150 absorbs moisture during heavy rams and becomes heavier, ma
placement/retrieval difficult. During freezing conditions, it can become slipper
and also freeze to wastes. SaniCover™ 250 does not absorb moisture, but in cc
weather moisture "trapped" between panel and working face can result in panei
freezing to waste. Panel useful life averages 20 days; maximum of 30 days.
Heavy rains/freezing conditions impact most on effective life. Both materials s
water from working face during rain events.
Stated Benefits: Saves landfill capacity (« R%). Is !*«« P»jv.ncjv« flmj easier t
apply than soil.
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Operational: Has used both SaniCover™ 150 and 750 fnr 2 yr Panels 75 by 1
ft (22.9 by 45.7 m) are placed with two compactors by attacbjng panel corners
with straps. Wrapping a ball/rock in the corner of the panel and then attaching
straps reduces tearing of panel. Soil placed onto edges and/or tires are used fo
anchoring. Soil is primarily used when wastes remain exposed after panel
placement, i.e., working face is larger then panels. Panels are anchored if win
exceed 10 mph (16 km/hr). Winds above 25 mph (40 km/hr) make panel
placement difficult. SaniCover™ 150 absorbs moisture. In whiter, SaniCover™
(Cont'd)
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Operational: Uses fully digested sludge on part (20%) of the
placed with the same equipment as soil in a 6-in. (15-cm) lay
climatic conditions, except heavy rains (it is more difficult to
effective cover, although odors are released for a short time 1
Stated Benefits: Saves landfill capacity (sludge would otherw
waste material) and conserves on-site soil. It also enhances d
•
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f-
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152
-------
GLOSSARY
Alternative Daily Cover Material (ADCM) - A commercially available or indigenous
material that may be used in lieu of soil as daily cover at landfills.
Bulk Storage and Dilution Unit (BSD) - RUSMAR® foam concentrate storage tank
equipped with a built-in dilution unit which automatically dilutes the foam
concentrate with water as it is transferred to a foam application unit.
ConCover® All Purpose Sprayer (CAPS! - A towed or skid-mounted spray unit
designed and configured to apply ConCover® slurry to the working face. The unit
can also be used for power-washing and fire fighting. .
Hvdroseeder - A device consisting of a liquid storage tank, high pressure pump
and spraygun used to apply a seed/fertilizer mixture to areas susceptible to
erosion along roadways, at construction sites, and at landfills.
Indigenous Material - A locally generated waste material that has been approved
for use as an alternative daily cover. Most of these materials require physical
or chemical modification, or evaluation for hazardous constituents, prior to
being considered acceptable for use as an daily cover.
Pneumatic Foaming Unit (PFUi - A self-propelled foam generation and application
unit designed and configured for the application of RUSMAR® foam to the working
face.
Sludge-derived Product (SDP> - A soil-like material produced from the treatment
of sludges with various additives including lime, cement kiln dust, and
silicates. SDPs can be used for agricultural and construction purposes, and for
daily, landfill cover.
Total Nonmethane Hydrocarbons (TNMHC1 - The total emissions of hydrocarbons, less
methane, as determined by gas chromatography using EPA Method TO-12.
153
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