Draft
Technical Background Document
on Ground Water Controls at CKD Landfills
Office of Solid Waste
U.S. Environmental Protection Agency
June 1998
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Table of Contents
Chapter 1: Characteristics of CKD Waste 1-1
1.1 Regulatory History 1-1
1.2 CKD Generation and Waste Management 1-2
1.2.1 Current CKD Generation Rates 1-2
1.2.2 CKD Recycling 1-4
1.2.3 CKD Beneficial Use 1-4
1.2.4 CKD Disposal 1-5
1.3 CKD Waste Characteristics 1-5
1.3.1 Physical Characteristics of CKD 1-5
1.3.2 Chemical Characteristics of CKD 1-7
1.3.3 CKD Toxicity 1-7
1.4 Need for a Standard 1-8
Chapter 2: Reasons for Agency Concern 2-1
2.1 Dangers to Ground Water Posed by Management of CKD 2-1
2.1.1 Ground Water Damage Cases 2-2
2.1.2 Factors Responsible for the Release of CKD Constituents into the
Environment 2-17
2.1.3 Current Trends in CKD Waste Management Practices 2-23
2.2 Dangers Posed by Location of CKD Disposal Areas Above Karst Aquifers and
Highly Fractured Media 2-23
2.2.1 Characteristics of Karst Aquifers and Ground Water Flow 2-23
2.2.2 Dangers Posed by Disposal in Karst Areas 2-27
2.2.3 Dangers Posed by Disposal in Highly Fractured Media 2-29
2.2.4 Agency Evaluation of Potentially Karstic Areas and Areas of High Fracture
Permeability 2-30
2.3 Damage to Wetlands, Lakes, and Streams Caused by Releases from CKD
Management Units 2-42
2.3.1 Wetland and Stream Damage From CKD Disposal 2-44
2.3.2 Lake Damage 2-44
2.4 EPA Conclusions Regarding Potential Impacts of CKD to Ground Water . . . 2-46
Chapter 3: Evaluation of Options for Technical Design Criteria for CKDLF Units 3-1
3.1 Identification and Evaluation of Options for Technical Design Standard 3-1
3.2 Landfill Design Configurations 3-2
3.2.1 Cement Industry's "Contingent Management Practices" for CKD 3-2
3.2.2 Baseline, Subtitle D, and Subtitle C Landfill Liner Designs 3-4
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3.2.3 "Modified CKD Low" and "Modified CKD High" Monofill Designs . . . 3-5
3.3 Overview of the HELP Model 3-6
3.4 CKD Landfill Modeling Results 3-7
3.5 Conclusions 3-8
Chapter 4: Agency Analysis of Ground Water Controls Required at Cement Manufacturing
Facilities 4-1
4.1 Development of the Decision Framework 4-1
4.2 Data Requirements and Data Collection 4-3
4.3 Application of the Decision Framework to the Cement Plant Database 4-4
4.3.1 Overview of MULTIMED Modeling Approach 4-11
4.3.2 MULTIMED Modeling to Establish Designs for CKD Landfills in Non-
Karst Environments 4-13
4.3.3 MULTIMED Results 4-14
4.3.4 Using MULTIMED DAFs to Evaluate CKDLF Designs Relative to the
Performance Standard in Non-Karst Hydrogeologic Settings 4-18
4.3.5 Summary Results of Application of the Decision Framework to the Cement
Plant Database 4-19
4.3.6 Assumptions and Limitations 4-21
4.4 Summary and Conclusions 4-21
Chapter 5: Summary of Proposed CKD Waste Management Standards for Protection of
Ground Water Resources 5-1
5.1 Location Restrictions 5-1
5.1.1 Prohibition of CKD Disposal Below the Natural Water Table 5-2
5.1.2 Floodplains 5-4
5.1.3 Wetlands 5-4
5.1.4 Fault Areas 5-5
5.1.5 Seismic Impact Zones 5-6
5.1.6 Unstable Areas Including Karst Terrains 5-7
5.2 Performance-Based Standard for Protection of Ground Water 5-9
5.3 Default Technical Design Criteria for CKDLF Units 5-10
5.4 Proposed Technical Requirements For Ground Water Monitoring 5-11
5.4.1 Ground Water Monitoring Well Design and Construction 5-12
5.4.2 Ground Water Sampling and Analysis Requirements 5-13
5.4.3 Statistical Analysis of Ground Water Monitoring Data 5-14
5.4.4 Detection Monitoring 5-15
5.4.5 Assessment Monitoring 5-16
5.4.6 Assessment of Corrective Measures 5-18
5.4.7 Selection of a Remedy 5-19
5.4.8 Implementation of Corrective Action 5-19
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11
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Chapter 6: Effectiveness of Proposed CKD Landfill Design Elements 6-1
6.1 Coal Ash Disposal at Selected Landfills in Pennsylvania 6-1
6.1.1 Montour Generating Station/Ash Storage Sites 2 and 3 6-2
6.1.2 Titus Generating Station/Beagle Club Ash Disposal Site 6-3
6.2 Comparison of Coal Ash Landfill Performance with Proposed CKD Landfill
Standards 6-4
6.2.1 Composite Bottom Liner 6-4
6.2.2 Alternative Bottom Liner Designs 6-5
6.2.3 Compaction of Fly Ash Waste 6-5
6.2.4 Landfill Closure and Post-Closure Measures 6-6
6.3 Comparison of Coal Ash Landfill Performance with Proposed CKD Landfill
Ground Water Monitoring Requirements 6-6
6.3.1 Ground Water Monitoring Design and Performance 6-6
6.3.2 Benefits of Ground Water Monitoring 6-7
6.4 Effectiveness of the Use of CKD as a Landfill Liner or Cover 6-8
6.4.1 Engineering Properties of CKD and CKD-Based Liners and Caps ... 6-9
6.4.2 Analysis of Instances Where CKD Was Considered or Used for a Landfill
Liner or Cap 6-21
6.4.3 Evaluation of Instances Where CKD Was Actually Used as a Cap or Liner
Material 6-41
6.4.4 Comparison of CKD Liners and Caps to Subtitle D and Subtitle C Liners
and Caps 6-44
6.4.5 Daily and Intermediate Landfill Covers Using CKD or CKD Based
Material 6-45
6.4.6 Cost Evaluation 6-47
6.4.7 Summary 6-49
Chapter 7: Site Characterization, Ground Water Monitoring, and Corrective Action .... 7-1
7.1 Site Characterization 7-1
7.1.1 Characterizing Site Hydrogeology in Karst Terrain 7-1
7.1.2 Data Required for Design of Ground Water Monitoring Systems in Karst
Terrain 7-3
7.1.3 Data Required for Design of CKDLF Units in Karst Terrain 7-5
7.2 Ground Water Monitoring 7-6
7.2.1 Need for Ground Water Monitoring at CKDLF Units 7-6
7.2.2 Implementation and Technical Considerations for Ground Water
Monitoring 7-6
7.3 Corrective Action 7-12
7.3.1 Need for Regulation and Regulatory Options Considered 7-13
7.3.2 Implementation and Technical Considerations for Corrective Action . 7-15
7.3.3 Applicability of Corrective Action Regulations 7-19
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111
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7.3.4 Benefits of Corrective Action
Draft: June 1998 IV
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Chapter 1: Characteristics of CKD Waste
Under Subtitle C of the Resource Conservation and Recovery Act (RCRA), the U.S.
Environmental Protection Agency (USEPA) is proposing a tailored set of standards for the
management of cement kiln dust (CKD) waste and to control releases to ground water. The
proposed standards are designed to protect human health and the environment, while allowing for
flexibility in their implementation by facilities and the States. This technical background
document (TBD) describes the Agency's development of proposed performance standards and
design and operating criteria for controlling releases to ground water at CKD landfill (CKDLF)
units.
1.1 Regulatory History
Under the 1980 amendments to RCRA, CKD was exempted from hazardous waste regulations,
pending completion of a Report to Congress required by §8002(o) and a determination by the
Administrator either to promulgate regulations under Subtitle C or that such regulations are
unwarranted. In December 1993, EPA issued a Report to Congress (RTC) on the hazards posed
by CKD. EPA solicited public comments on the report and held a series of public meetings in
early 1994 before determining that CKD warranted additional controls.
To supplement the information included in the RTC, the Agency analyzed the public comments
submitted on the RTC and undertook several additional data collection and analysis efforts. The
new data generated by EPA were placed into the RCRA docket for public inspection and
comment and a Notice of Data Availability (NOD A) was published in the September 14, 1994,
Federal Register (59 FR 47133).
In February 1995, EPA announced its intention to develop controls on CKD under Subtitle C of
RCRA to protect public health and the environment (60 FR 7366, February 7, 1995). The
decision followed an extensive evaluation that included consultation with states, industry and
citizen groups. In that regulatory determination, EPA announced its intention to use, as
appropriate, its various authorities under the Clean Air Act, Clean Water Act, and RCRA to
address the relevant pathways of potential contaminant releases from CKD. This document was
prepared to provide technical background information on the need for ground water controls at
CKDLF units. Controls for CKD fugitive air emissions are described in a separate docket report
on standards for control of fugitive dust at CKD landfills.
After publication of the Regulatory Determination on CKD in 1995, EPA embarked on a series of
analyses to identify and evaluate options for the protection of ground water resources at CKDLF
units. The objective of these analyses was to develop tailored technical standards that are
protective of human health and the environment but with sufficient flexibility for local
implementation by facilities and the States. To develop the proposed standards, EPA evaluated
the results of risk modeling, documented damage cases, conducted hydrogeologic modeling, and
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1-1
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conducted other technical and regulatory analyses to evaluate a range of alternative performance
and technical standards. After consideration of these analyses, the Agency developed and is
proposing a set of performance standards and operating criteria to minimize the impact of CKD
land disposal practices to ground water.
1.2 CKD Generation and Waste Management
Recent information collected by the Agency1 suggests that the cement industry consisted of 110
plants in the United States and Puerto Rico operated by 46 companies. The five largest clinker2
producing states are California, Texas, Pennsylvania, Missouri, and Michigan. Cement production
occurs in very large rotary kilns at high temperatures; finely ground raw material enters and rolls
downward from the "cool end" of the kiln, while fuels and combustion are introduced and drawn
upward from the "hot end". Large amounts of high Btu fuels, primarily coal and other fossil fuels
are used during the cement manufacturing process to maintain adequate burning temperatures
within kilns. In 1997, hazardous waste was found to have been burned as a cement kiln fuel at a
total of 18 cement plants. As air exits the cool end, entrained solid matter, including CKD, is
collected before the air is vented to the atmosphere through large gas emission smokestacks.
CKD generation results directly from this control of particulate matter that would otherwise be
discharged. Usually 98 to 100 percent of all particulate matter generated during cement
production is captured by air pollution control devices before existing the kiln system (USEPA,
1993). This material is comprised of raw materials, dehydrated clay, decarbonated (calcined)
limestone, ash from burnt fuel, and newly formed minerals produced by the cement manufacturing
process. This gross CKD may be recycled, treated and reused; taken off-site for beneficial use; or
disposed of in waste management units (see Figure 1-1).
1.2.1 Current CKD Generation Rates
Based on an analysis of existing data, including data collected by the Portland Cement Association
(PCA) and separately by EPA under RCRA section 3007 authority from operators of cement
manufacturing facilities, the Agency estimates that in 1995 the cement industry had a clinker
capacity of 77 million metric tons and a net CKD generation of 4.08 million metric tons. The
1995 data indicate that 24 of the 110 cement plants (22 percent) recycle all collected dust back to
the kiln, and an additional 12 plants (11%) ship all generated CKD off site for beneficial use. The
Agency estimates that the remaining two-thirds of cement plants (74 facilities) had a combined
annual CKD land-disposal requirement of 3.3 million metric tons in 1995.
1 Portland Cement Association (PCA) 1995 survey of the cement industry in 1995.
2
Clinker is the cement kiln's raw product which is subsequently ground with a smaller amount (approximately 5
percent) gypsum to make cement.
Draft: June 1998 1-2
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GROSS CKD
(Collected at Air Pollution Control
Devices)
RECYCLED CKD
(Returned to Kiln)
NET CKD
(Removed from Kiln)
TREATED AND
RETURNED TO
KILN
SOLD OR GIVEN
FOR BENEFICIAL
USE
DISPOSED IN
WMU
Figure 1 -1. Flow Chart of Gross CKD Management Practices.
(Adapted from EPA, 1993)
Draft: June 1998
1-3
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These facilities employ on-site disposal for CKD quantities ranging from less than 1,000 metric
tons per year up to more than 200,000 metric tons per year. (See Section 5 of this background
document for a more detailed description of facility-specific CKD generation rates).
1.2.2 CKD Recycling
Recycling of CKD reduces the need for land disposal or other alternative uses of CKD.
Accordingly, most facility operators recycle CKD to some degree. Based on data from a 1995
PC A survey (representing usable data from 108 facilities), most facilities recycle some of their
gross CKD, and 24 facilities were able to recycle all of their CKD (PCA, 1995). In 1995, two
thirds of the gross CKD that was generated by the cement industry - 7.8 million metric tons - was
recycled directly back into the kiln or raw feed system. If a cement plant achieves 100 percent
recycling, alternative CKD management practices, such as land disposal, are deemed unnecessary.
However, direct recycling generally results in a gradual increase in the alkali content of generated
dust that may damage cement kiln linings, produce inferior cement, and increase particle emissions
from the plant. Depending on the quality of the raw materials used, increased concentrations of
chloride and sulfur in cement may produce structurally-defective concrete. Some CKD removal
from the kiln system as waste is therefore usually necessary (USEPA, 1993).
Several cost-effective treatment technologies are available or are being developed to treat CKD
with high concentrations of alkalies and/or other undesirable constituents before re-entry to the
kiln system. At some cement plants, dust reuse is preceded by pelletizing or alkali leaching. (At
least two facilities are known to treat waste CKD with water leaching: the Ash Grove Cement
Co., Inkom, Idaho, and Holnam Inc., Dundee, Michigan.) Pelletizing gives CKD the strength to
withstand firing upon re-entry into the kiln system without resuspending large quantities of
particulate matter or changing the chemical characteristics of clinker. The leaching process
increases the amount of recyclable CKD but generates wastewater that must be treated for high
pH values and high concentrations of dissolved and suspended solids. However, no wastewater
discharge is associated with this procedure. At one facility, a modified version of this leaching
and return process reportedly results in 100 percent recycling of CKD (USEPA, 1993).
In addition, the Agency has received some evidence, in comments from cement companies, that
raw material substitution may be a highly effective means of increasing CKD recycling rates. This
may be done by controlling the input of contaminants (in raw materials and fuels) to the kiln
system, thereby reducing or eliminating the need to purge the kiln system of contaminants (60 FR
7366).
1.2.3 CKD Beneficial Use
Alternatively, CKD may be sold or given away for off-site applications. Beneficial uses of waste
CKD include the stabilization of municipal sewage sludges, waste oil sludges, and contaminated
soils; the neutralization of acid mine drainage; the addition to agricultural lands as a fertilizer
and/or liming agent, and inclusion in Portland cement as a materials additive. In 1990, about 7
Draft: June 1998
1-4
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percent of the CKD generated (897,000 metric tons) was sold for off-site use. Mostly, CKD was
used as waste stabilizer, liming agent, and materials additive (60 FR 7366). In 1995,
approximately 767,740 metric tons were sold off-site for beneficial use (PCA, 1995).
1.2.4 CKD Disposal
In 1995, land disposed CKD averaged 30,150 metric tons per plant, and land disposed CKD from
the entire cement manufacturing industry was estimated to be 3.3 million metric tons (PCA,
1995). Typically, CKDLF units are on-site, non-engineered, unlined and uncovered landfills and
piles located in abandoned quarries, retired portions of operating quarries or nearby ravines.
Some active piles are also managed underwater or adjacent to surface water and/or agricultural
lands (60 FR 7366). Based on data from the 1990 PCA survey, the Agency has estimated that 52
percent of active CKD disposal facilities were landfills, 43 percent were piles, and less than 1
percent were ponds (USEPA, 1993). The average pile was 15 meters (15 m) thick or 1 m thicker
than the average landfill. Maximum reported thicknesses for CKD landfills and waste piles were
56.4 m and 34.6 m, respectively. However, the average basal area for landfills (7.9 hectares) was
approximately twice that of piles (3.6 hectares). Landfills may therefore cover significantly larger
land areas than piles. In contrast, the average basal area of ponds was less than 1 hectare.
Non-CKD waste materials such as, furnace brick, concrete debris and tires may be co-disposed
with CKD in CKDLFs. Responses to the PCA survey reveal that of 66 CKDLFs, 23 percent co-
disposed non-CKD material amounting to 1 percent of the material disposed in these units in
1990.
Based on the Agency's analysis of current CKD waste management practices and the causative
factors of releases to ground water at CKDLFs, current landfill designs appear to be inadequate to
limit contaminant releases from CKDLFs. Current trends in CKD waste management practices
are discussed in greater detail in Section 2.1.3.
1.3 CKD Waste Characteristics
CKD waste characteristics generally are affected by natural variations in the raw materials used
for cement manufacture, product specifications, the type of process employed by the facility, and
the type of fuel burned. This section describes the physical and chemical characteristics of CKD,
and CKD toxicity based on corrosivity and trace metal concentrations. The presence of volatile
and semi-volatile organic compounds in CKD also will be discussed.
1.3.1 Physical Characteristics of CKD
Fresh CKD is a fine, dry alkaline dust that readily absorbs water. CKD particle sizes generally
vary by kiln process type (see Table 1-1) and range from 0-5/iin (approximately clay size) to
greater than >50//m (silt size) (USEPA, 1993).
Draft: June 1998
1-5
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' 'able 1-1. Particle Size Distribution of CKD by Process Type.
Particle Size
(M m)
Source la
Source 2b
Unspecified
Process Type
(weight
percent)
Wet Kilns
(weight
percent)
Long Dry Kilns
(weight
percent)
Dry Kilns with
Precalciner
(weight
percent)
0-5
5
26
45
6
5-10
10
19
45
11
10-20
30
20
5
15
20-30
17
9
1
23
30-40
13
8
1
18
40-50
7
1
0
9
>50
18
17
3
18
Median
Particle Size
No Data
9.3
3.0
22.2
a Kohlhaas et al. 1983. Cement Engineer's Handbook. Bauverlag GMBH, Wiesbaden and Berlin, p. 635. The
number of samples used to develop data was not specified.
b Todres et al. 1992. CKD Management: Permeability. Research and Development Bulletin RD103T, Portland
Cement Association, Skokie, Illinois, p. 2.
Permeability or saturated hydraulic conductivity data for CKD samples collected from four
locations are as follows:
Minimum:
Maximum:
Median:
Average:
2.6 x 10"8 cm/s
1.7 x 10"4 cm/s
1.2 x 10"5 cm/s
1.8 x 10"5 cm/s
These values are based on 175 construction and test plot results using samples collected during
the design and/or pre-construction phase of CKDLF units. This range of CKD permeability
values is similar to permeabilities found in natural materials ranging from that of a typical
unweathered clay (a nearly impervious soil type with permeabilities less than 10"7 cm/sec) to that
of a silty sand (a low permeability soil type with permeabilities ranging from 10"3 to 10"5 cm/sec).
Additional data on the physical properties of CKD and an evaluation of the use of compacted
CKD as a landfill liner or cap are presented in Section 6 of this background document.
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1.3.2 Chemical Characteristics of CKD
The primary bulk constituents in CKD (those found in quantities greater than 0.05 percent by
weight) are silicates, calcium oxide, carbonates, potassium oxide, sulfates, chlorides, various
metal oxides and sodium oxide. EPA found that CKD may contain seven trace metals (antimony,
cadmium, lead, mercury, selenium, silver, and zinc) at levels above the range commonly found in
native soils.3 In addition, CKD may contain arsenic and strontium at levels that are within the
range of naturally occurring soils, but that exceed the average native soil concentration by a factor
of two or more (USEPA, 1993).
1.3.3 CKD Toxicity
CKD contains certain metals listed in 40 CFR 261 Appendix VIII ("Hazardous Constituents").
Table 1-2 presents the range of total concentration levels for a number of toxic metals identified in
CKD. EPA found that when total metals detected in kiln dust are considered, no significant
distinction can be made between CKD generated from kilns that burn hazardous waste and those
that do not burn hazardous waste. However, for individual metals such as, lead and cadmium, the
mean concentration found in CKD generated by kilns that burn hazardous waste is measurably
higher than that produced in kilns that do not burn hazardous waste. Conversely, thallium and
barium concentrations are measurably higher in CKD from kilns that do not burn hazardous waste
(60 FR 7366).
Due to the generally alkaline nature of CKD, the pH level in storm water runoff that contacts
CKD waste piles typically exceeds 12.5 standard units (SU) (60 FR 7368), the federal standard
for the corrosivity characteristic for hazardous wastes (40 CFR 261.22). Ground water releases
and surface water runoff from CKD piles can have significant impacts on aquatic environments.
For example, as a part of a preliminary site characterization of the Lehigh Portland Cement
Company site in Metaline Falls, Washington, fish toxicity testing was conducted on juvenile
rainbow trout in accordance with Washington State Department of Ecology Static Acute Fish
Toxicity Test, No. DOE 80-12 (Dames and Moore, 1992). The test was performed to evaluate if
CKD could be considered a dangerous waste under Washington regulations (Washington
Administrative Code 173-303-100). Testing involved adding 1,000 ppm of CKD to water in an
aquarium containing rainbow trout and observing fish mortality over 96 hours. Of the ten non-
neutralized bioassays conducted, four of the tests exceeded the toxicity criteria for dangerous
waste. Two fish bioassay tests had pH values exceeding 10.5 SU and had 97 percent and 100
percent mortality rates. Four of the tests had pH values equal to 10.5, but the two of these tests
that failed the toxicity criteria showed mortality rates of 100 percent (Dames and Moore, 1992).
Source: Hazardous Waste Land Treatment. Table 6.46 - Trace Elements of Soils, U.S. Environmental Protection
Agency, Cincinnati, Ohio, PB89-179014, April 1983, page 273. See Section 3 of EPA's Report to Congress on
Cement Kiln Dust (Vol. IIMethods and Findings) for a more detailed discussion of the chemical characteristics of
CKD.
Draft: June 1998
1-7
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e 1-2. Trace IV
etal Concentrations in CKD fmg/kg (parts per million), total basis].
Analyte
No. of Samples
Mean
Minimum
Maximum
Antimony
52
11.5
0.99
102
Arsenic
60
14.1
0.26
80.7
Barium
59
181
0.43
900
Beryllium
53
1.03
0.1
6.2
Cadmium
61
9.7
0.005
44.9
Chromium
61
31.2
3.9
105
Leadb
63
287
3.1
2620
Mercury
57
0.33
0.003
2.9
Nickel
45
19.9
3
66
Selenium
52
12.2
0.1
103
Silver
56
5.9
0.25
40.7
Thallium
57
33.5
0.44
450
(From USEPA 1995)
a Metals data sources include 1992 PC A, EPA sampling data, and public comments on the RTC.
b The median value for lead is 113 mg/kg.
The CKD present at the site was subsequently designated as a Washington State dangerous waste
(Ecology, 1994).
Volatile and semi-volatile organic compounds are generally not found in CKD due to the
combustion of these compounds at the high temperatures encountered in the kiln. However,
generally low concentrations of 2,3,7,8-substituted dioxin (0.5 to 20 parts per trillion (ppt)) and
2,3,7,8-substituted dibenzofuran (non-detected to 470 ppt) were detected (USEPA, 1995).
1.4 Need for a Standard
Although CKD is a solid waste under RCRA, present Federal regulations only apply to landfills
used to dispose of hazardous wastes (under RCRA Subtitle C) and municipal wastes (under
RCRA Subtitle D). Unless covered by existing state regulations or the cement manufacturing
facility burns RCRA hazardous waste, CKDLF units are not required to comply with any
operations code, meet any design criteria, or monitor for off-site leachate migration. The findings
of EPA's 1995 Regulatory Determination (supported by the Report to Congress, the NOD A, and
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subsequent work) demonstrate that new regulatory controls under RCRA are justified based on
potential and actual impacts to ground water from current CKD management practices.
Screening level risk analyses showed that CKD poses a potential threat to ground water resources
at cement plants land disposing CKD over aquifers located in physiographic areas characterized
by karst topography4, and more than half of cement plants in the United States are located in karst
areas. Due to the methodological limitations of quantitative modeling of karst hydrogeologic
settings, EPA is using damage cases to document potential risks to ground water posed by the
mismanagement of CKD. Damage cases account for actual site conditions that cannot be
replicated easily in risk modeling (e.g., karst hydrogeology, combined contamination from other
release sources, or elevated background levels of chemicals at specific sites), or consider non-
compliance or upset situations that are not considered within the scope of a risk assessment.
These damage cases are described in Chapter 2 of this background document.
The proposed regulatory controls to protect ground water resources at CKD disposal sites were
developed after an evaluation of a range of potential landfill designs and consideration of
regulatory mechanisms already in place to protect ground water at municipal solid waste landfills
and hazardous waste landfills. The framework of how the proposed CKD waste management
regulations were developed is described in Chapters 3 and 4. The proposed regulations to control
the release of waste CKD constituents to ground water are summarized in Chapter 5. An
evaluation of how effectively the standards are expected to perform and factors to be considered
during implementation of the rule are discussed in Chapter 6 and 7, respectively. The proposed
ground water controls are flexible, and can be tailored to site-specific conditions. EPA believes
this approach avoids over regulation and provides adequate environmental protection at a
reasonable cost.
4 A type of topography that is formed on limestone, dolomite, gypsum, and other soluble rocks by dissolution. It has
a distinctive hydrogeology and landforms, composed of soluble rocks and well developed secondary porosity enhanced
by dissolution. Ground water flow generally occurs through an open system with both diffuse and conduit flow end
member components, and typically has rapid ground water flow velocities. See Sections 2.2.1 and 2.2.2 of this
Technical Background Document for additional information on the dangers posed by CKD disposal in karstic
hydrogeologic settings.
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References
Dames and Moore, 1992. Preliminary Site Characterization Report. Prepared for Lehigh
Portland Cement Company, Metaline Falls, Washington. Job No. 00691-004-005.
Ecology, 1994. Letter from K. Stoffel and B. Howard, State of Washington, Department of
Ecology to T. Kessler, Lehigh Portland Cement Company. April 11, 1994.
Kohlhaas, B., et al., 1983. Cement Engineer's Handbook. Bauverlag GMBH, Wiesbaden and
Berlin. P.624.
Portland Cement Association (PCA), 1995. U.S. and Canadian Portland Cement Industry: Plant
Information Summary (December 31, 1995).
Todres, H., Mishulovich A. and Ahmed, J., 1992. CKDManagement: Permeability. Research
and Development Bulletin RD103T. Portland Cement Association, Skokie, 111.
USEPA, 1998. Technical Background Document: Design and Operating Standards or Control
of Fugitive Dust at CKD Landfills.
USEPA, 1995. 40 CFR Part 261 Regulatory Determination on Cement Kiln Dust: Final Rule.
Federal Register, Vol. 60 No. 25 (Tuesday, February 7, 1995).
USEPA, 1994. Notice of Data Availability, Human Health and Environmental Risk Assessment
in Support of the Report to Congress on Cement Kiln Dust. EPA Office of Solid Waste.
August 31, 1994, Revised per Federal Register Notice of October 11, 1994.
USEPA, 1993. Report to Congress on Cement Kiln Dust, Volume IIMethods and Findings.
EPA Office of Solid Waste. December 1993.
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Chapter 2: Reasons for Agency Concern
This chapter summarizes the Agency's concern about past and current CKD waste disposal
practices. This chapter focuses on the dangers posed by mismanagement of CKD and the
causative factors for the release of CKD constituents into the subsurface environment. At least
thirteen CKD disposal sites have been identified where ground water has been contaminated with
CKD constituents. These ground water damages cases are described in Section 2.1. Many of the
damage cases involve release of CKD constituents into karst aquifers which are characterized by
conduit ground water flow (Section 2.2) and to wetlands (Section 2.3). Contamination of karst
aquifers and wetlands poses a unacceptable threat to human health and the environment. In
Section 2.4, the Agency concludes that current CKD waste management practices are inadequate
and that it is necessary to establish performance standards and technical design standards for CKD
waste management units.
2.1 Dangers to Ground Water Posed by Management of CKD
In the Report to Congress on CKD (USEPA, 1993a) and the subsequent Notice of Data
Availability (NODA) (59 FR 47133) and Regulatory Determination (60 FR 7366), EPA presented
data showing CKD contains certain toxic metals (40 CFR Part 261 "Appendix VIII - Hazardous
Constituents"), low concentrations of dioxin and dibenzofuran, and when mixed with water often
exhibits the characteristic of corrosivity (40 CFR Part 261.22)1. EPA documented evidence of
damage to ground water and identified potential risks to human to human health and the
environment from on-site management of CKD. Evaluation of CKD management practices, site-
specific hydrogeologic information, and damage cases revealed potential risks not identified by
means of conventional risk modeling studies. For example, screening level and subsequent
modeling did not adequately model the intrinsic on-site variability of current CKD disposal
practices. Neither the MMSOILS model nor the EPACMTP model can simulate disposal below
the ground water table, which is a factor in some of the damage cases. Also, EPA has determined
that approximately half of all cement plant sites are underlain by carbonate formations (limestone
or dolomite) which may exhibit a distinctive hydrology typical of karst settings (60 FR 7366). In
karst hydrogeologic settings, CKD leachate potentially can enter ground water in a relatively
undiluted state and rapidly migrate off-site through open conduits enhanced by dissolution. In
addition, EPA has found that on-site management practices for CKD include land-disposal of
CKD in quarries below the natural water table and in unlined landfills, piles, and ponds. CKD
landfills generally lack liners, covers, leachate controls, or run-on/run-off collection systems.
For these reasons, EPA developed and applied an alternative screening analysis. The results of
this analysis, as described in Section 2.2.2, showed that CKD poses a potential threat at cement
plants land-disposing CKD over karst aquifers.
1 EPA hazardous waste identification rules do not include a characteristic or definition for solid corrosives.
Draft: June 1998 2-1
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EPA also prepared new damage case reports to supplement those prepared for the Report to
Congress (RTC) and the NODA. Damage cases account for actual site conditions that cannot be
replicated easily in risk modeling (e.g., complex, site-specific contaminant fate and transport).
Damage cases also can account for regulatory non-compliance or upset situations that are not
captured by risk modeling. In areas where the quantitative modeling results are limited or cannot
be generated because of methodological limitations, EPA is using the damage cases to document
releases to ground water posed by current CKD management practices.
2.1.1 Ground Water Damage Cases
In the 1993 RTC, EPA identified and documented 19 cases of damage to ground water and
surface water in response to Section 8002(o)(4) of RCRA which required EPA to study CKD
waste to examine "documented cases in which danger to human health or the environment has
been proved".2 Of these 19 damage cases, five cases documented damages to ground water.
EPA's analysis of documented evidence of damage showed that migration of potentially
hazardous constituents, including toxic metals, has occurred from cement kiln dust waste sites.
Since publication of the RTC and the Regulatory Determination on Cement Kiln Dust (see 60 FR
7366), eight additional ground water damage cases came to the attention of the Agency (USEPA,
1997a). In total, thirteen of these damage cases involve contaminant releases to ground water,
and these cases are summarized in Table 2-1. Each of the cases presented in Table 2-1 meets the
requirements outlined in Section 5.0 of the Report to Congress (USEPA, 1993a). These "tests of
proof' consist of three separate tests; a case that satisfies one or more of these tests is considered
"proven." The tests are as follows:
• Scientific investigation. Damages are found to exist as part of the findings of a
scientific study. Such studies should include both formal investigations supporting
litigation or a state enforcement action, and the results of technical tests (such as
monitoring of wells). Scientific studies must demonstrate that damages are
significant in terms of impacts on human health or the environment. For example,
information on contamination of a drinking water aquifer must indicate that
contamination levels exceed drinking water standards.3
• Administrative ruling. Damages are found to exist through a formal administrative
2
These documented and potential damages from the management of cement kiln dust are described in Chapter 5 of the
Report to Congress on Cement Kiln Dust (see 59 FR 709, January 6, 1994) and subsequent Notice of Data Availability (see 59 FR
47133, September 14, 1994). Supporting documentation for damage cases described in the Report to Congress and subsequent
Notice of Data Availability are available for public inspection in the USEPA RCRA Docket Nos. F-94-RCRA-S0106 to -S0179, and
F-94-RC2A-S0003 to -S0015. Additional documentation of six ground water damage cases is provided in a Technical Background
Document entitled "Additional Documented Damages to Ground Water from the Management of Cement Kiln Dust" (USEPA,
1997a).
3
EPA recognizes that comparison of drinking water standards and constituent levels in ground water is not routine, but
because of the lack of benchmark standards for constituents in leachate, the Agency believes it is a useful comparison.
Draft: June 1998
2-2
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ailing, such as the conclusions of a site report by a field inspector, or through
existence of an enforcement action that cited specific health or environmental
damages.
Court decision. Damages are found to exist through the ruling of a court or
through an out-of-court settlement.
Draft: June 1998
2-3
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Alamo Cement An unknown quantity of CKD and mine
Co. - Highway overburden waste was disposed of in two landfills
281 Disposal at a now abandoned cement manufacturing facility.
Area, San One landfill has a clay liner and cap. The other, a
Antonio, Texas quarry covered with a clay cap, contains CKD,
chromium brick, and an estimated 40 million
gallons of leachate. Falling leachate levels suggest
downward migration into the underlying faulted
bedrock. However, elevated levels of Cr or pH
have not been detected by surrounding monitoring
wells. A golf course has been constructed on the
site, and lands adjacent to the quarry have been
converted into residential areas. In 1990, a plan to
close the facility as a Class I Non-Hazardous
Industrial Solid Waste Management Facility was
submitted to the Texas Natural Resources
Conservation Commission (TNRCC) and
approved, with modifications, in 1992. On
February 14, 1994, a letter from TNRCC rejected
the plan, requested a post closure plan, stated that
the Texas Water Code had been violated and that
falling leachate levels in the landfill indicated that a
release had occurred.
Releases beyond
facility boundary
undetermined.
Within landfill
(a) exceeds EPA's
toxicity level: Cr;
(b) elevated: pH
Possibly ground water
infiltration into the pile
The site is located in karst terrain.
Proposed ground water controls for
CKD landfills in karst (composite
liner with a leachate collection
system) could have prevented
releases.
Draft: June 1998
2-4
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Ash Grove CKD disposed in two landfills located in a nearby
Cement Plant, abandoned limestone quarry. One landfill has been
Chanute, inactive since the early 1970s. The other is a
Kansas permitted solid waste landfill a part of which is
used to dispose of CKD. In early 1996, disposal
activities began in the formerly unused portion of
the landfill. On March 16, 1996, the Kansas
Department of Health and Environment (KDHE)
filed a Notice of Non-Compliance with the plant
after a KDHE inspector noted seeps with elevated
pH values leaving the landfill and entering a local
tributary of the Village Creek. In response, Ash
Grove conducted a site assessment which included
a hydrogeologic investigation, and implemented
immediate remediation control measures.
Approximately 3,000 people and one private well
are within 1.6 km (one mile) of the main facility.
Implemented Controls: surface regrading, interim
trench pumping, application to dispose of
deactivated leachate at Chanute's POTW.
Ground Water (a)
exceeds MCLs: As,
Be, Pb; (b) exceeds
Federal Secondary
Drinking Water
Standards: Fe; (c)
elevated: pH
Surface Water
elevated: pH
(a) Surface water (rain)
infiltration and percolation
through the landfill and
underlying fractured Paola
Limestone unit, and
(b) man-made drainage
features (e.g. drainage sumps
and ditches) cut into the
former quarry floor that
facilitate gravity-driven lateral
ground water flow through the
landfill.
The landfills are underlain by a
limestone unit with a high potential
for conduit (non-Darcy) flow.
Proposed ground water controls for
CKD landfills in karst (composite
liner with a leachate collection
system) could have prevented
releases.
Proposed Controls: interceptor trench with
geosynthetic liner, pump and treat trench leachate.
Draft: June 1998
2-5
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Holnam Inc., From 1969 to 1985, CKD was landfilled in an
Mason City, abandoned, unlined quarry partially filled with
Iowa precipitation and ground water (water table rises
into quarry). Two shallow aquifers in vicinity of
facility supply potable water. In 1980, the quarry
water pH had risen to 12.8. A quarry dewatering
program was initiated in 1987 and resulted in
lowering the pH level to 10.5 by 1990. A blowout,
or seep, was observed in quarry wall in 1984, with
high pH (11.3) and elevated S04, Na, K, and
phenol. This seepage flowed to Calmus Creek,
which exhibited elevated turbidity, S04, and K.
The State of Iowa ordered Holnam to cease
disposal of CKD in quarry in 1985. Elevated pH
levels in Calmus Creek resulted in a fish kill in
September 1986. The site was listed on the NPL
in August, 1990 due to contaminated surface and
ground water, primarily elevated pH and mineral
deposition. The site was removed from the NPL in
1996.
Ground Water (a)
exceeds Federal.
Primary Drinking
Water Standard Cr;
(b) exceeds
Federal. Secondary
Drinking Water
Standards: pH,
TDS, Fe, S04
Surface Water
exceeds state
standard: pH in
Calmus Creek
(a) Disposal of CKD in quarry
below water table, creating
hydrogeologic communication
with ground water, (b)
overland flow of quarry water
to Calmus Creek, and (c)
ground water discharge to
Calmus Creek.
The site is located in a karst area and
CKD is disposed below the natural
water table. A prohibition on
disposal of CKD below the natural
water table would have prevented
direct contact of CKD leachate and
ground water. Proposed ground
water controls for CKD landfills in
karst (composite liner with a leachate
collection system) could have
prevented releases.
Implemented Controls: Facility ceased disposal in
the quarry in lieu of recycling CKD to kiln. Also
completely dewatered quarry in 1989; constructed
drain system in quarry to collect run-off and ground
water inflow; placed clay cap over CKD in quarry
to minimize infiltration; and installed bedrock
extraction wells to prevent migration of
contaminated ground water from site.
Draft: June 1998
2-6
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Lehigh Portland This plant lies to the north of the Holnam Inc. site.
Cement Co., Calmus Creek flows between the two plants. Prior
Mason City, to beginning landfilling CKD in 1986, Lehigh
Iowa deposited CKD at various locations throughout
site, including several inactive quarries and on a
site adjacent to the Winnebago River known as the
"Badlands" area. Elevated pH was observed in
1981 in one of the four quarries. In 1984, it was
found that contamination of Calmus Creek was
related to discharges from one of the quarries via a
tile drain outlet. The discharges exhibited a pH of
11.4 and TDS of 4,700 mg/L. At the State's
request, Lehigh eliminated discharge to the creek.
EPA determined in 1987 that the quarry ponds and
ground water underlying the site were
contaminated. Elevated pH was also observed in
ground water beneath the Badlands area. Ground
water underlying the adjacent Lime Creek Nature
Center, a past disposal site, was also found to be
contaminated during a RI/FS investigation
conducted in 1989-90. EPA listed the site on the
NPL in 1990, but following litigation, removed the
site due to issues regarding the site's hazard
ranking score.
Implemented Controls: Diversion ditches, dikes,
capping and slurry walls around quarries. A water
treatment system was constructed.
Ground Water
exceeds (a) Federal
primary drinking
water standards:
As, Pb; (b)
exceeds Federal
Secondary Drinking
Water standards:
pH, TDS, S04, Fe
Surface Water
exceeds State
surface-water
discharge
standards: pH
(a) Disposal of CKD in quarry
below water table, creating
hydrogeologic communication
with ground water, (b)
overland flow of quarry water
to Calmus Creek, and (c)
ground water discharge to
Calmus Creek.
The site is located in a karst area, and
CKD is disposed below the natural
water table. A prohibition on
disposal of CKD below the natural
water table would have prevented
direct contact of CKD leachate with
ground water. Proposed ground
water controls for CKD landfills in
karst (composite liner with a leachate
collection system) could have
prevented releases.
Draft: June 1998
2-7
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Medusa Cement CKD (2 million tons since 1968) disposed of in
Co., Charlevoix, nine different piles in an abandoned, on-site quarry
Michigan underlain by fractured limestone bedrock. The
present quarry floor is approximately 31 feet below
Lake Michigan's water level. Medusa estimates
that 75% of the materials have been placed above
ground surface. At pile 9 (current disposal site), a
portion of the CKD is below the water table. A
dewatering system is in place to control shallow
ground water flow at the base and rim of the
quarry. Surface runoff from the base of the quarry
is discharged into Lake Michigan in accordance
with an NPDES permit. Leachate impacted
ground water from piles 4, 5, 6, and 9 within the
quarry appear to be responsible for several
discolored seeps on the Lake Michigan shoreline.
Three private water wells are within one-half mile
of piles 6 and 9.
Ground Water (a)
exceeds Michigan
GSI regulatory
limit: Cu, Mn, Ni,
Se; (b) exceeds
HBDW limit: Se;
(c) exceeds State
Aesthetic Drinking
Water Value: Fe;
(d) elevated: pH, K,
CI, S04
Surface Water
elevated: pH, As,
K
(a) Infiltration of ground
water into the CKD
materials, and (b) the
movement of leachate
impacted ground water into
the shallow flow system at the
rim of the quarry and into the
deeper bedrock aquifer via
conduit flow.
The site is within a matured karst
terrain that is characterized by
numerous sinkholes, closed
depressions and vertical shafts that
extend beneath the land surface.
Proposed ground water controls
(including a composite liner, leachate
collection system, effective
dewatering system that extended at
least 150 meters from the landfill,
stormwater management controls,
and a ground water monitoring
system) could have reduced surface
and ground water damage. However,
additional engineering measures
might be required to prevent releases
through the highly fractured and
porous limestone walls of the quarry.
Draft: June 1998
2-8
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Penn-Dixie The site, approximately 430 hectares (1060 acres),
Cement, lies along 10 km (6.5 miles) of Little Traverse Bay
Petroskey, shoreline which is adjacent to Lake Michigan. It
Michigan has been inactive since approximately 1980, when
it was purchased by the Bay Harbor Company for
redevelopment into a resort area. CKD was
disposed of on-site in three piles overlying
fractured limestone bedrock. Impacted ground
water and surface runoff flow into Lake Michigan
from one large pile (the central western pile).
Ground water damage is also attributed to the
eastern pile. Surface water damage was
documented in the damage case supporting the
1994 Notice of Data Availability. Hydrogeologic
investigations of the central western and eastern
piles were conducted as part of the Bay Harbor
Administrative Agreement and a Covenant-Not-
To-Sue between the developers and the State of
Michigan. In 1995, a Closure Activity Plan was
initiated.
Ground Water
exceeds (a) MCL:
Pb; (b) Federal
Secondary Drinking
Water Standards:
pH, TDS; (c) State
Ground water
Criteria: Na, S04,
As, Fe, Pb, Cd; (d)
State Water Quality
Standards: As, Cr,
Cu, Pb, Hg, Ni
(a) Surface water
(precipitation) infiltration into
the pile; (b) possibly ground
water infiltration into the pile
Since the site is in a karst terrain,
CKD disposal in a covered landfill
with a bottom liner, leachate
collection system, stormwater
management system, and a ground
water monitoring and sampling
system could have prevented impact
on surface water and ground water.
Damage could also have been
avoided if location restrictions on
siting the landfill adjacent to the lake
had been in place.
Draft: June 1998
2-9
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Signal Approximately 900,000 metric tons of CKD were
Mountain disposed of by the previous owner, General
Cement Co., Portland Cement Company, in a closed landfill
Chattanooga, located in an old on-site quarry. CKD was also
Tennessee emplaced in wall cavities adjacent to the landfill.
These cavities are connected to underground
caverns beneath Signal Mountain. Ground water
from the cavities and surface runoff from the
landfill discharge into a tributary of the Tennessee
River. The plant is located near to the Signal Hills
and Carriage Hill communities. Since 1977, the
State has attempted to have the discharges brought
into compliance with its effluent standards. After a
1994 State inspection, a NOV was issued to the
current owner.
Ground Water
exceeds Federal
Secondary Drinking
Water Standard: pH
Surface Water
exceeds RCRA
hazardous
characteristic of
corrosivity: pH
(a) Disposal of CKD into
ground water pools inside
quarry cavities, (b) ground
water infiltration into the pile,
and (c) uncontrolled surface
runoff from the pile
The site is located in a mature karst
terrain. Stormwater management
and proposed ground water controls
for CKD landfills (composite liner
with leachate collection system and
ground water monitoring system)
could have prevented surface and
ground water damage.
Proposed Controls:
Dewatering the landfill to (a) prevent ground water
seeps and (b) control annual recharge.
Draft: June 1998
2-10
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Southdown, CKD disposed in ten unlined landfills in on-site
Inc., Fairborn, quarries between 1924 and 1978. Contaminant
Ohio releases have been observed in surface and ground
waters adjacent to Landfills #1 and #6. Ohio EPA
collected samples from seeps and streams at the toe
of Landfill #6 having elevated levels of As, Fe, Se,
Pb, and pH. Ground water samples revealed
elevated levels of As, Fe, and Se. In 1992, OEPA
issued an administrative enforcement order
requiring a CERCLA Remedial Investigation and
Feasibility Study; as of December, 1993, this study
had yet to be initiated. OEPA also reported
elevated levels of As, Fe, and Se in seeps at the toe
of Landfill #1.
Ground Water
exceeds (a) Federal
primary drinking
water standards:
Pb; (b) State
drinking water
standards: As, Cd,
Cr, Ni
Surface Water
exceeds State
drinking water
standards: As, Cd,
Cr, Fe, Se, pH
Disposal of CKD in unlined
landfills. CKD leachate
released to ground water and
surface water.
The site is located in a karst area.
Proposed ground water controls for
CKD landfills in karst (composite
liner with a leachate collection
system) could have prevented
releases to ground water.
Draft: June 1998
2-11
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Texas In 1992, Texas Water Commission inspectors
Industries, Inc., observed pools of reddish-brown liquid seeping
Midlothian, from an inactive, unlined CKD pile that lies in the
Texas facility's quarry. Elevated levels of As, Pb, and pH
were observed. TWC issued a NOV letter to the
facility for violations of solid waste rules. After a
subsequent inspection yielding similar results, EPA
filed a letter of complaint for violations of RCRA
Subtitle C regulations. Though seepage was
observed only in localized pools, potential is
believed to exist for contaminant to migrate beyond
plant boundaries. In particular, uncontrolled run-
off from the CKD pile would flow into two
adjacent streams. Furthermore, the TWC
concluded in a 1990 inspection that the potential
exists for contaminant release from both the active
and inactive landfills due to (1) a shallow water
table, (2) a high volume of dust in the active
disposal area, (3) the lack of a landfill liner, and (4)
the proximity of the active landfill to ponded water.
No off-site releases
observed.
Potential Releases
to Surface Water
elevated: As, Pb,
Cr, and pH in
pools collected at
the base of the
inactive CKD pile.
Potential Releases
to Ground Water
elevated pH,
laboratory
conductivity
significantly above
background
elevated Pb, Cr, Cd
in soil
(a) Disposal of CKD in
unlined piles in a quarry
overlying shallow ground
water, creating potential for
contaminant migration to
nearby perched ground water
bodies (b) potential for storm
water run-off from CKD piles
to enter adjacent streams.
Ground water contamination
attributed to rain water
percolating through CKD.
The site is located in a karst area.
Proposed ground water controls for
CKD landfills in karst (composite
liner with a leachate collection
system) would prevent potential
releases to ground water.
Furthermore, the Agency's storm-
water permitting program would
require run-on/run-off controls that
could prevent surface water
contamination.
Draft: June 1998
2-12
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Lehigh Portland Until 1989, CKD (estimated to be approximately
Cement Co., 544,000 tons) was disposed in a waste pile along
Metaline Falls, the margin of Sullivan Creek valley. The creek is
Washington populated by cutthrout trout and drains to the Pend
Oreille river. Ground water flowing beneath the
pile appears to discharge to seeps and springs
along the creek, as well as to wetlands and
distributary channels adjacent to the creek.
Damage to soil, surface and ground water is
documented. In 1981, the State began enforcement
of RCRA and its solid waste and water pollution
control laws. In 1989, Lehigh sold the facility to
Lafarge Corporation. Ownership of the CKD
disposal site was retained. Since 1990, the State
has sought closure of the disposal site. In 1995,
Lehigh submitted its Final Closure Plan which was
later revised on April 11, 1996. A "Post Closure
Care and Maintenance Plan" has also been
presented.
Implemented Controls: regrade the pile, construct
and maintain a cover, construct and maintain a
storm water management system, and continue
ground water sampling and monitoring to
determine if cap construction reduces surface water
infiltration and improves the ground water quality
of the site.
Ground Water (a)
exceeds MCLs:
Ag, As, Cr, Ni, Pb,
Tl, pH, Fe; (b)
exceeds State
MTCA A Cleanup
Level: As, Ba, Cr,
Cd, Ni, Ag, Tl, Pb,
pH; (c) exceeds
State water quality
levels: pH, Fe
Surface Water
exceeds State
MTCA B Cleanup
Level: pH, Pb, As,
Hg, Se, Zn
Soil
elevated:
pH, Cr
(a) Ground water seepage into
the pile, (b) capillary rise of
the ground water table into the
pile, and (c) surface water
infiltration into the pile.
The waste pile is located near to a
floodplain and wetlands area, and
underlain by limestone bedrock.
Location restrictions (such as those
for solid waste landfills), a storm
water management system, and the
proposed ground water controls for
CKD landfills (a cover, composite
liner, leachate collection system),
could have prevented surface and
ground water damage.
Draft: June 1998
2-13
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Markey Site consists of a four-acre CKD landfill on
Machinery industrial property located within 4,000 feet of the
Property, Duwamish River, a state-designated fishery. CKD
Seattle, is believed to have been disposed by Ideal Cement.
Washington Run-off from the site flows to Ham Creek, which
discharges to the Duwamish River. Depth to
ground water is less than 25 feet. Ground water
samples collected in 1989 revealed concentrations
of metals below drinking water limits, but lead
concentrations exceeded state cleanup levels.
Surface-water samples collected from a ditch on
the eastern edge of the site had a pH of 10.2 and a
lead concentration approximately 25 times the
federal drinking water limit. The state has ranked
the site three on a scale of one to five, with one
representing the highest level of concern and five
the lowest.
No off-site releases
observed. On-site
surface water
concentrations of
Pb observed at
levels 25 times the
federal drinking
water standard.
Potential Releases
to Surface Water:
Elevated pH and
Pb.
Potential Releases
to Ground Water:
Elevated levels of
Pb.
(a) Large volume (38,250
cubic meter) of CKD; (b)
absence of run-on/run-off
controls, cover, liner, or
leachate containment system;
(c) proximity to population
center; and proximity to
waters designated as a state
fishery.
Use of a composite liner and leachate
collection system could prevent
ground water damage.
Best management practices required
under the NPDES storm-water
permit system would alleviate
concern over run-off to the
Duwamish River.
Elevated levels of
As, Cu, Pb, and Zn
in soils exceeding
state soil cleanup
standards
Draft: June 1998
2-14
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Table 2-1. Summary of Documented Ground Water Damages
Site Damage Case Summary Reported Causative Effectiveness of Proposed Ground
Releases Factors Water Controls
The area is underlain by a limestone
bedrock. Releases could have been
prevented if (a) CKD had been
disposed of in a landfill with a cover,
a bottom liner, a leachate collection
system, a stormwater management
system, and a ground water
monitoring system, and (b) location
restrictions had been applied to
prohibit siting of the landfill next to a
lake.
company to prevent further erosion and deposition cleanup criteria:
of contaminants into the lake. New information As, Se, Zn, Pb
indicates the pile has contributed to ground water
contamination. Monitoring wells located adjacent
to and hydraulically downgradient of the pile (on
the Systech property) show ground water
contamination attributable to the pile.
Implemented Controls:
Final closure and a maintenance and monitoring
plan for the site are in progress. No ground water
response actions have been proposed as no ground
water contamination has been detected in the
monitoring wells currently on the Lafarge property.
National National Gypsum formerly disposed CKD on a 30
Gypsum Co., hectare site on the shore of Lake Huron. Disposal
Alpena, began in the early 1900s and ceased in 1986, when
Michigan Lafarge took over operations. Erosion channels
from the pile lead to the lake, and wave action has
eroded the pile's southern edge. Surface water
samples collected from the erosion channels and
Lake Huron show levels of As and Pb in excess of
state standards specified under the Michigan
Environmental Response Act. The state has
negotiated interim response actions with the
Ground Water
exceeds State
cleanup criteria: CI,
S04, Ba, Cr, Pb
Surface Water
exceeds State
standards: As, Pb
Soil
exceeds State soil
(a) Location of the pile along
the shores of the lake, (b) lack
of surface water runoff
controls, (c) surface water
(rain) infiltration into the pile,
and (d) CKD leachate
released into the ground
water.
Draft: June 1998
2-15
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Table 2-1. Summary of Documented Ground Water Damages
Site
Damage Case Summary
Reported
Releases
Causative
Factors
Effectiveness of Proposed Ground
Water Controls
Portland From 1965 to 1983, CKD was disposed in five
Cement off-site, unlined piles in and around Salt Lake City.
Company, Salt The two largest sites are listed on the NPL as the
Lake City, Utah Portland Cement Superfund Site. This site is
adjacent to two surface water features, a storm
water drain and an irrigation canal. Chromium-
bearing refractory bricks were co-disposed with
the dust. The Record of Decision concluded that
soil, ground water and surface water are
contaminated with CKD constituents (As, Cr, Pb).
A contaminant plume is present in shallow ground
water underlying and adjacent to the piles, with
elevated pH, Mo, As, Cr, Cd, and Pb. In addition,
elevated pH, Pb, and As have been observed in
surface water at the site.
Implemented Controls: Excavation and off-site
disposal of CKD and As- and Pb- contaminated
soil in a state-approved, solid waste landfill. Off-
site disposal of chromium-bearing bricks at a
hazardous waste TSD facility. A minimum of two
feet of clean backfill will be used to cover the site
and additional ground water monitoring and
institutional controls will be initiated following
CKD removal actions in 1997.
Ground Water
exceeds Federal
Primary or
Secondary Drinking
Water Standards:
As, Cd, Cr, Pb, pH,
TDS
Surface water in
On-Site Ephemeral
Ponds exceeds
Federal Primary or
Secondary Drinking
Water Standards:
As, Pb, pH
Surface Water in
City Storm Water
Drain contains
elevated levels of K
and pH.
(a) Disposal of CKD in
unlined piles overlying
shallow, unconfined ground
water adjacent to surface
water features; (b) lack of
surface-water controls.
Location restrictions against CKD
disposal in wetlands, floodplains, and
below the natural water table could
have prevented damage to ground
water.
EPA's new storm water permit
program could have prevented the
surface-water damages through best
management practices such as run-
on/run-off controls.
Al=aluminum, As=arsenic, Ba=barium, Be=beryllium, Cd=cadmium, Cl=chloride, Cr=chromium, Cu=copper, F=fluoride, Fe=iron, Hg=mercury, Pb=lead,
Mn=manganese, Mo=molybdenum, Ni=nickel, K=potassium, Se=selenium, Na=sodium, S04=sulfate, Tl=thallium, TDS=total dissolved solids, Zu=zinc
Draft: June 1998 2-16
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In 12 of the 13 damage cases listed in Table 2-1, Federal Primary or Secondary Drinking Water
Maximum Contaminant Levels [MCLs] or state clean-up levels were exceeded in ground water.
At one additional site, Alamo Cement in San Antonio, Texas, no analytical ground water data are
available but regulators with the Texas Natural Resource Conservation Comission have stated
that declining leachate levels in the landfill indicate releases of hazardous constituents into waters
of the State. At eight of the ground water the damage case sites, concentrations of arsenic,
beryllium, cadmium, chromium, lead, selenium, and/or thallium exceed the Federal Primary
Drinking Water MCLs.
Of the thirteen ground water damage cases, the Portland Cement Company site in Salt Lake City,
Utah is listed on the Superfund National Priority List (NPL) Holnam, Inc. and Lehigh Portland
Cement Company sites in Mason City, Iowa were formerly listed on the NPL. The Holnam site is
remediated and the Lehigh and Portland Cement Company sites are in the process of remediation.
Constituents of concern most commonly released to ground and surface waters included arsenic,
chromium, and lead, and contaminated waters also show a significant increases in pH. When
constituents were found at elevated levels, they were generally less than two orders of magnitude
above Federal or State MCLs for drinking water.
Although environmental releases and resultant damages generally affected the area in the
immediate vicinity of the waste disposal site, in some cases, nearby wetlands and streams that are
off-site were also impacted. For example, releases of toxic constituents from the Lehigh and
Holnam facilities in Mason City, Iowa caused severe degradation of the aquatic habitat in nearby
Calmus Creek. Discharges of contaminated water from surface water run-off, drainage tiles, and
ground water seeps to Calmus Creek resulted in a fish kill in September 1986 and a dominance of
pollution-tolerant fish and benthic species for about 2 miles down stream from the two facilities
(USEPA, 1997b and 1997c).
Releases from the Lehigh and Southdown, Inc. CKD disposal units in Metaline Falls, Washington
and Fairborn, Ohio, respectively, have resulted in ground water and local surface water
contamination and pose a threat to wetland environments. Off-site ground water seeps near the
Metaline Falls facility have been documented to be very alkaline (pH up to 14 SU) and to contain
elevated concentrations of lead (up to 0.027 mg/L) and arsenic (up to 0.077 mg/L) (USEPA,
1997d). Surface water at the Fairborn facility have pH levels as high as 13.6 SU and contained
elevated concentrations of arsenic (up to 0.83 mg/L), cadmium (up to 0.02 mg/L), chromium (up
to 0.105 mg/L), lead (up to 0.070 mg/L) and selenium (up to 0.07 mg/L) (USEPA, 1993a).
Damages to wetlands and surface water bodies from CKD units are discussed in greater detail in
Section 2.3.
2.1.2 Factors Responsible for the Release of CKD Constituents into the Environment
As documented in Table 2-1 there are many factors which have contributed to causing the release
of CKD constituents to ground water or the subsurface environment. Factors which are noted to
have contributed to the release of CKD constituents into the sub-surface environment include:
Draft: June 1998
2-17
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• Presence of a shallow ground water flow system with conduit flow characteristics
(e.g., karst aquifer or fractured bedrock aquifer) (Alamo Cement, San Antonio,
TX; Ash Grove, Chanute, KS; Holnam, Mason City, IA; Lehigh, Mason City, IA;
Medusa, Charlevoix, MI; and Signal Mountain, Chattanooga, TN);
• CKD disposal below the natural water table or ground water infiltration into the
waste unit (Ash Grove Cement, Chanute, KS; Holnam, Mason City, IA; Lehigh,
Mason City, IA; Medusa, Charlevoix, MI; Penn-Dixie, Petrosky, MI; Signal
Mountain, Chattanooga, TN; Southdown, Fairborn, OH; Lehigh, Metaline Falls,
WA; Portland, Salt Lake City, UT);
• Lack of a bottom liner and/or leachate collection system to control leakage from
the waste unit (all ground water damage cases);
• Lack of an impermeable cover to control percolation of rain water and/or surface
water into the waste unit (none of the damage case sites maintained a cover during
the active life of the disposal unit);
• Surface run-off or erosion transporting CKD constituents to surface water bodies
and/or wetlands which can serve as a source of ground water recharge (Holnam,
Mason City, IA; Lehigh, Mason City, IA; Signal Mountain, Chattanooga, TN;
Southdown, Fairborn, OH; National Gypsum, Alpena, MI; Portland Cement, Salt
Lake City, UT); and
• Construction of man-made drainage features which contributed to the lateral
migration of CKD constituents (Ash Grove, Chanute, KS).
The frequency at which the first five of these factors has occurred at the thirteen CKD ground
water damage case site is presented in Table 2-2. All of the damage cases were associated with
CKD waste units which did not have bottom liners, leachate collection systems and impermeable
covers in place during the active disposal period. Since the release, a number of these facilities
have installed impermeable covers and/or dewatering systems to minimize the migration of CKD
constituents and mitigate further environmental damage.
The damage cases presented in Table 2-1 and Table 2-2, indicate that conduit ground water flow
in karst aquifers and in fractured bedrock is an important factor in the migration of CKD
constituents in the subsurface environment for at least six of the damage case sites.
Disposal of CKD below the natural water table is of particular concern to EPA. Contaminated
ground water and surface water near at least nine of these facilities resulted primarily from CKD
disposal below the water table and/or from direct CKD contact with the shallow ground water
system. Figured predominantly among these damage cases are three sites that were listed on the
NPL (Holnam, Mason City; Lehigh, Mason City; and Portland, Salt Lake City). At the two
Draft: June 1998
2-18
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Mason City sites, contaminant migration was facilitated by diffuse and conduit flow within a
fractured and locally karstic limestone formation. The environmental dangers posed by CKD
releases to karst aquifers and wetlands/surface water bodies are discussed in more detail in
Sections 2.2 and 2.3, respectively. As discussed in greater detail in Chapter 3 and 6 of this
background document, the Agency believes the use of ground water controls such as bottom
liners, impermeable landfill covers, and leachate collection systems will minimize the threats to
ground water such as those documented in the damage cases, especially in areas with karst
hydrogeologic environments.
At many of these sites, environmental damages are persistent and continuing. Receipt of
additional environmental monitoring data since the 1995 Regulatory Determination has enabled
the Agency to identify eight more cases of ground water damage (USEPA, 1997a). This indicates
that damage to ground water resources near CKD disposal sites may be more common that
originally thought in 1995. At the former National Gypsum (Alpena, Michigan), Penn Dixie
Cement (Petoskey, Michigan), and Texas Industries (Midlothian, Texas) sites ground water
contamination has been found which corroborated the surface water damage cases which were
reported in the 1993 RTC. Many of these sites have been slow to implement remedial measures
to control off-site migration of contaminants. For example at the old National Gypsum waste
pile, CKD has been eroding into Lake Huron over a number of years.
At only seven of the ground water damage case sites have remedial measures been initiated, such
as removal of contaminated materials (i.e., Portland Cement Co., Salt Lake City, Utah),
installation of an impermeable cap and/or construction of a seep/ground water extraction and
treatment system. Releases from the Portland Cement Superfund Site in Salt Lake City, Utah
have resulted in a ground water plume of about 50 acres in size with arsenic, chromium, cadmium,
and lead concentrations exceeding Federal and Utah drinking water MCLs. The clean up costs
associated with excavation and off-site disposal of CKD, contaminated soil, and chromium-
bearing refractory bricks have exceeded $30 million at this site (USEPA, 1997e).
The Agency expects that there are many other CKD disposal sites with damages to ground water,
besides those listed in Tables 2-1 and 2-2. Based on the Portland Cement Association (PCA)
Plant Information Summaries for the years 1974, 1990, and 1993, there are about 1200 inactive
CKD piles located at 96 active and 95 inactive cement plants in the United States. At the end of
1995, approximately 180 million metric tons of CKD was stored in these piles (SAIC, 1996). It
was noted in the 1995 Regulatory Determination, that of the 14 CKD disposal sites where ground
water monitoring data have been collected, all but one of the sites indicate some ground water
contamination has occurred (60 FR 7366). Clearly there is a need to perform ground water
monitoring at CKD disposal sites in order to identify and remediate contaminated ground water
and to evaluate and remediate potential releases to ground water from active CKD landfill
(CKDLF) units.
Draft: June 1998
2-19
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Table 2-2. Factors Contributing to Release of CKD Constituents to Ground Water
Damage Case,
City, State
(Reference)
Geologic
Condition
Contributing to
Release
CKD In Contact
with Ground
Water or Disposed
Below Natural
Water Table?
Bottom Liner
Present?
Leachate
Collection System
Present at Time of
Release?
Impermeable
Cover Present?
Close Proximity to
Wetland or
Surface Water
Body?
Alamo Cement Co.,
San Antonio, TX (59
FR 47133)
Faults located in close
proximity to landfill.
Area underlain by
Edwards Limestone
which exhibits karst
features.
No
One landfill has a clay
liner the other is
unlined
No, accumulation of
rainwater during
active period is source
of leachate
Yes, clay caps
installed during landfill
closure
No
Ash Grove Cement,
Chanute, KS (USEPA,
1997a)
Fractured limestone
bedrock
Portion of landfill
located below water
table
No
No
No
Seeps from landfill
discharged to a local
tributary
Holnam, Inc., Mason
City, IA (USEPA,
1993a and 1997b)
Shallow karst aquifer
CKD disposed of in a
former quarry which
later filled up with rain
and ground water
No
No, dewatering system
installed to collect and
treat ground water in
the disposal area
86-acre clay cap
installed as part of
remedial measure
Blow out from quarry
disposal area to
Calmus Creek resulted
in a fish kill
Lehigh, Inc., Mason
City, IA (USEPA,
1993a and 1997c)
Shallow karst aquifer
CKD disposed of in
former quarries which
later filled up with rain
and ground water
No
No, dewatering system
installed to collect and
treat ground water
from the disposal area
Clay caps over CKD
disposal areas installed
as part of remedial
measure
Contributed to
contamination in
Calmus Creek
Medusa Cement Co.,
Charlevoix, MI
(USEPA, 1997a)
Mature karst terrain,
shallow karst aquifer
The lowermost
portions of three CKD
piles are below the
water table
No
Quarry dewatering
system does not
capture all
contaminated ground
water migrating from
disposal site
No
High pH seeps are
located near the Lake
Michigan shoreline
Draft: June 1998
2-20
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Damage Case,
City, State
(Reference)
Geologic
Condition
Contributing to
Release
CKD In Contact
with Ground
Water or Disposed
Below Natural
Water Table?
Bottom Liner
Present?
Leachate
Collection System
Present at Time of
Release?
Impermeable
Cover Present?
Close Proximity to
Wetland or
Surface Water
Body?
Penn-Dixie Cement,
Petrosky, MI (59 FR
47133, USEPA,
1997a)
Site underlain by karst
and fractured
limestone bedrock
which potentially
facilitated the release
Likely potential for
ground water
infiltration into CKD
waste piles
No
No, sump collection
system proposed near
seepage areas
Soil cover proposed as
part of remedial
measures
High pH seepage from
CKD piles have
flowed into Lake
Michigan
Signal Mountain
Cement Co.,
Chattanooga TN
(USEPA, 1997a)
Cavernous karst
aquifer
CKD disposed of in
water-filled quarry
cavities
No
No, a landfill
dewatering program
has been proposed
Unlikely, landfill
closed before 1984
CKD sediment and
High pH leachate have
been released to an
unnamed tributary of
the Tennessee River
since 1977
Southdown, Inc.,
Fairborn, OH
(USEPA, 1993a)
Thin bedded limestone
bedrock dominated by
diffuse flow ground
water system
CKD was landfilled in
unlined quarries, high
pH seeps near
Landfills #1 and #6
indicate that CKD is in
contact with ground
water
No
None present
Unspecified
Landfill #1 is adjacent
to Mud Run, Landfill
#6 is adjacent to
wetlands
Texas Industries, Inc.,
Midlothian, TX (59
FR 47133)
Shallow contaminated
ground water is
perched on shale unit;
deeper potentially
karst aquifer is not
believed to have
contributed to the
release
CKD disposed of in an
unlined quarry, high
pH seeps and ponds
near one of the waste
piles indicate that
CKD is in contact
with shallow ground
water
No
None present
Unspecified
Disposal area is
adjacent to two
streams
Lehigh Portland
Cement Co., Metaline
Falls (USEPA, 1997d)
Underlain by alluvial
deposits (non-karst)
Lowermost portion of
CKD pile below water
table
No
None Present
Engineered composite
cap installed as part
remedial measure
Waste pile adjacent to
two intermittent creeks
which discharge to
Sullivan Creek
Draft: June 1998
2-21
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Damage Case,
City, State
(Reference)
Geologic
Condition
Contributing to
Release
CKD In Contact
with Ground
Water or Disposed
Below Natural
Water Table?
Bottom Liner
Present?
Leachate
Collection System
Present at Time of
Release?
Impermeable
Cover Present?
Close Proximity to
Wetland or
Surface Water
Body?
Markey Machinery
Property, Seattle, WA
(USEPA, 1993a)
Non-karst area
Unspecified if CKD is
in contact with ground
water
No
No
No
Adjacent to the site are
two surface drainages
which discharge to
Ham Run and
Duwamish River
National Gypsum Co.,
Alpena, MI (USEPA,
1997a)
Waste pile located on
carbonate bedrock, but
local conditions are
not karst
Unspecified
No
No
No
Wave from Lake
Huron has eroded the
CKD pile for a
number of years
Portland Cement Co,
Salt Lake City, UT
(USEPA, 1993a and
1997e)
Alluvial and lacustrine
sediments (non-karst)
CKD was used as fill
over alkali saltmarsh
land, lower portions of
former waste piles
were below shallow
water table
No
No
No
Site is adjacent to City
Drain and Jordan
Surplus Canal
Summary
At least 4 cases
where karst
conditions and 2
cases where
fractured bedrock
contributed to a
release
9 cases where CKD
was in direct contact
with ground water
13 cases with no
bottom liner
13 cases with no
leachate collection
system; 5 cases
proposed or are
using ground water
dewatering systems
4 cases involve
installation of
covers during site
closure; none used
covers during the
active life of waste
unit
There are concerns
over wetlands or
nearby surface
water features for
12 cases
Draft: June 1998
2-22
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2.1.3 Current Trends in CKD Waste Management Practices
In the 1993 RTC, it was noted that current waste management practices appear to be inadequate
to limit contaminant releases from CKD waste management units (WMUs). According to a PCA
survey, 78 percent of all respondents indicated that their landfills had liners, but none included
synthetic liners for the year 1990. Only 11 percent of the facilities reported using a modified
natural liner. The remainder considered in-situ bedrock or clay/shale units to be liners. Fifty-one
percent practice some form of run-off control, but only 18 percent practice some form of leachate
control. Approximately 14 percent of existing WMUs use slurry walls around the units, and just
20 percent use other forms of environmental protection including soil caps, clay caps, berms, rip-
rap caps, and trees (USEPA, 1993a).
A more recent survey was conducted by the PCA in 1995 (PCA, 1996). According to this
survey, sixty-five percent of all respondents indicated that their landfills had liners, but only one
respondent (1.5%) used a synthetic liner. About thirteen percent of the respondents used
recompacted shale/clay and about thirty-two percent of the respondents used compacted CKD as
a bottom liner, respectively. The remainder considered bedrock or native clay/shale materials to
be liners. Seventy-seven percent of the respondents claimed to use some form of run-on/run-off
controls and twenty two percent used leachate controls. The 1991 and 1995 PCA surveys
indicate that CKD waste management practices generally rely on inadequate measures to control
the release of contaminants to ground water and that these practices have not changed
substantially or have only marginally improved over the past several years.
2.2 Dangers Posed by Location of CKD Disposal Areas Above Karst Aquifers and
Highly Fractured Media
The Agency believes that there are increased risks to ground water when CKD is disposed in an
area with karst aquifers or highly fractured geologic media. These areas of concern may have
ground water flow systems with rapid ground water flow velocities which can exceed the upper
limit of Darcy's Law (e.g., conduit flow). Many cement plants are located in limestone karst
areas due to the fact that cement plants frequently locate near a minable source of limestone.
Sections 2.2.1 and 2.2.2 discuss the characteristics of karst aquifers and the dangers associated
with disposal in karst areas, respectively. Section 2.2.3 examines the dangers of disposal in non-
karst areas but also characterized by ground water systems with non-Darcy, conduit-flow. The
Agency's evaluation of CKD disposal in potentially karst and/or highly fractured areas is
summarized in Section 2.2.4
2.2.1 Characteristics of Karst Aquifers and Ground Water Flow
The hydrogeology of karst terrain has been studied extensively due to the importance of karst
aquifers as sources of drinking water throughout the U.S. and their susceptibility to
contamination. EPA's Environmental Research Laboratory, Athens, Georgia, prepared a status
Draft: June 1998
2-23
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report on flow and transport modeling karst aquifers (USEPA, undated) that reviews current
literature and presents an excellent overview of the physical characteristics of karst terrain. Karst
aquifers are characterized by diffuse and conduit ground water flow systems where ground water
flow may be very rapid and controlled by fractures and dissolution channels.
The fundamental hydrologic difference between porous media aquifers and karst (and fractured
media) aquifers is ground water flow in excess of the Darcian ground water velocity. In mature
karst systems, the dominant basin wide flow component is rapid, turbulent ground water
movement (non-Darcian flow) through conduits to one or more springs that can vary in
magnitude based on the size of the basin and seasonal ground water conditions. A ground water
basin in the initial stages of karst development with almost none of or widely dispersed surface
features characteristic of a mature karst terrain may have a basin-wide conduit system that
consists of small tubes less than one foot in diameter with ground water flow velocities exceeding
hundreds of meters per day (Smith, 1997).
Characterization of hydraulic parameters (e.g., porosity, hydraulic conductivity) associated with
karst aquifers is much more difficult than that associated with porous media aquifers (e.g., sands
and gravel). The difficulty of characterizing karst aquifers with a conduit-flow component is due
its heterogenous distribution of the fractures and dissolution channels. Modeling of ground water
flow pathways and velocities in a karst aquifer will have a high degree of uncertainty unless there
is effort to accurately characterize the hydraulic characteristics of the karst aquifer and to locate
the preferential flow paths.
Karst terrain is characterized by both surface and subsurface features such as sinkholes, karst
windows, springs, caves, and losing, sinking, gaining, and underground streams (Mull et al.,
1988). Sinkholes represent a common hazard in karst terrain and can provide a direct conduit for
surface runoff to recharge karst aquifers, potentially acting as a direct source of contamination to
the aquifer. Karst aquifers are sometimes difficult to identify, particularly if the karst aquifer is
overlain or masked by a competent geologic formation or if affected by recent geomorphic
processes such as glaciation or alluviation (covered with stream deposits).
Most karst terrain is underlain by limestone or dolomite rock, although some may be underlain by
gypsum, halite, or other soluble rocks. EPA's status report provides a brief overview of how
karst aquifers are formed (USEPA, undated). In the limestone and dolomite bedrock systems in
which karst aquifers are principally formed, the calcium carbonate and magnesium carbonate
forming the bedrock system are dissolved by a weak carbonic acid formed by the dissolution of
carbon dioxide in water. Over time, the movement of this weak acid through fissures and pores in
the limestone bedrock dissolves the carbonate rock and forms progressively larger openings that
facilitate fluid flow through these conduits. This progressive dissolution results in an evolution of
karst aquifers over time; "immature" karst aquifers primarily consist of small pores and fractures
that may only be interconnected to a limited extent, and "mature" karst aquifers consist of highly
interconnected dissolution channels, conduits, and caves that facilitate rapid flow of ground water.
Draft: June 1998
2-24
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Based the current understanding of karst terrain and the relative importance of karst aquifers as a
drinking water source susceptible to contamination, the Agency is proposing the following
definition for karst terrains:
Karst terrains means areas where karst landscape, with its characteristic
hydrogeology and/or landforms are developed. In karst terrain ground water flow
generally occurs through an open system with both diffuse and conduit flow end
member components, and typically has rapid ground water flow velocities which
exceed Darcian flow velocities. Composed of limestone, dolomite, gypsum and
other soluble rock, karst terrain typically has well developed secondary porosity
enhanced by dissolution. Landforms found in karst terrain include, but are not
limited to, sinkholes, sinking streams, caves, springs and blind valleys. Karst
terrains always include one or more springs for each ground water basin, and
underground streams except where ground water flow is diffuse or the host rock
has megaporosity.
Ground water flow in karst aquifers is different from ground water flow in porous aquifers
because of the common presence of conduits (i.e., fractures, fissures, and large interconnected
voids). Ground water flow in porous aquifers can be characterized by Darcy's Law, which relates
the flow rate to the hydraulic gradient, the porosity of the aquifer medium, and the hydraulic
conductivity of the aquifer medium. Ground water flow in karst aquifers with a conduit flow
component does not follow the conceptual model reflected by Darcy's Law, but represents a more
complex and heterogeneous process. Darcy's Law does not apply to situations where ground
water flow is turbulent and where the aquifer media can not be characterized by a "representative
elementary volume" or a volume which permits meaningful statistical averaging of the aquifer's
hydraulic properties. Fractures and dissolution channels in karst aquifers cause ground water to
flow along preferential pathways and will have a much higher ground water flow rates (e.g.,
turbulent flow may occur in large fractures or dissolution channels) than the adjacent media.
Ground water flow controlled by preferential pathways (e.g., fractures and dissolution channels) is
termed conduit flow, which is in contrast with flow which occurs through out a porous media.
Because the distribution of these preferential pathways is often heterogeneous, the porosity and
hydraulic conductivity associated with the karst aquifer's representative elementary volume will
have little meaning on a practical (site-specific scale) or have a high degree of uncertainty. Karst
aquifers have been classified into three types based on ground water flow characteristics (Mull et
al., 1988):
• Diffuse-flow karst aquifers: Diffuse-flow karst aquifers form in areas where the
solution activity has been retarded, limiting the development of caves and large
conduits. Rather than concentrating flow in large caves or conduits, flow occurs
through relatively diffuse seeps and fractures.
• Free-flow karst aquifers: Free-flow or conduit flow aquifers are characterized by
well-defined and integrated systems of enlarged conduits that behave hydraulically,
Draft: June 1998
2-25
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like a system of pipes. Flow velocities are similar to surface streams and are often
turbulent. Regional discharge may be through a single large spring. Water levels
and flow rates may often respond rapidly to precipitation events.
• Confined-flow karst aquifers: Confined-flow karst aquifers represent karst
aquifers that are bounded by low permeability confining beds, resulting in karst
flow at greater depths than typically found in surficial free-flow aquifers. The flow
occurs in systems of interconnected joints rather than the master conduits found in
free-flow aquifers.
Because ground water flow in more developed karst aquifers can be similar in nature to surface
stream flows, such aquifers can be highly susceptible to contamination. Whereas the relatively
slow movement of ground water through a porous aquifer (such as a sand/gravel sedimentary
aquifer) can naturally retard or fix through adsorption the movement of organic and inorganic
contaminants, there may be little opportunity for contaminant attenuation in conduit flow karst
aquifers. Consequently, contaminants entering these aquifers can be transported rapidly to
discharge points with only that reduction in concentration associated with the dilution of the
leachate in the base ground water flow. The vulnerability of a karst aquifer will vary according to
the ability of the waste unit to contain waste constituents, the nature of the contaminant, the
presence of surface karst features such as piping or solution conduits, the degree of contact
between the infiltrating water and the soil zone, and the type and volume of karst aquifer flow.
Where a karst aquifer is used as a source of drinking water, the potential for contamination of the
drinking water supply will depend on the extent to which flow underlying the contaminant source
(e.g., a CKD pile) is interconnected with the ground water withdrawal points (i.e., public or
private wells or springs). In cases where the source and the withdrawal points are directly
connected through large conduits, there is a significant potential for direct and rapid long distance
transport of constituents to the drinking water well (diluted by the base ground water flow). In
certain diffuse flow systems or even free-flow karst aquifers where the solution cavity flow paths
do not connect the contaminant source to the withdrawal point, there may be virtually no
transport of contaminants from the source to the exposure point (even in cases where the two
points may be in relatively close proximity). Consequently, the exposure potential in karst
settings can range from very high to negligible, depending on highly site-specific aquifer
characteristics. At the Holnam damage case site in Mason City, Iowa, the blow out of CKD
contaminated water, flowing at a rate of up to about 150 gallons/minute, to Calmus Creek from
the CKD disposal area, demonstrates that conduit flow in karst aquifers can be an important
factor in the migration of CKD contaminants.4 This blow out, as well as other seeps from the
Holnam and Lehigh properties, were noted to have contributed to the September 1986 fish kill
4 At the Holnam and Lehigh sites in Mason City, IA, the upper aquifer consists of Devonian limestones with
"solution-enlarged fractures", and physiographic features include "karst topography". Source: Layne Geosciences, Inc,
1989, Remedial Investigation/Feasibility Study on the West Quarry, Mason City, Iowa, prepared for Northwestern States
Portland Cement (project No. 61.1099), page 13 and Figure 4, respectively.
Draft: June 1998
2-26
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and degraded the aquatic habitat in Calmus Creek from 1984 until 1992 (USEPA, 1997b).
2.2.2 Dangers Posed by Disposal in Karst Areas
Risks associated with CKD disposal in karst areas include structural failure of the waste unit due
to ground instability and the potential for contaminated ground water to migrate long distances
through open conduits with little filtration, adsorption, and dispersion that are typical of
contaminant dispersal in porous geologic formations. Concerns about potential adverse
foundation conditions in karst areas are discussed in Section 2.2.2.1. The risks posed by CKD
waste units in karst areas to contaminate ground water are evaluated in Section 2.2.2.2.
2.2.2.1 Foundation Conditions in Karst Areas
Stable foundation conditions are fundamental to the successful performance of any engineered
structure. Foundation soils, such as expansive clay and soils subject to rapid settlement and
liquefaction, are examples of foundation conditions that could result in impairing or destroying the
integrity of landfill design elements such as liners, leachate collection systems, and caps (USEPA,
1993b). Foundation stability in karst areas is of specific concern due to the potential for sudden
failure of the subsurface, causing sinkholes that can be more than 100 feet or more in depth and
300 feet or more in width (USEPA, 1993b). The principal engineering concern with karst areas is
progressive and/or catastrophic failure of the subsurface due to the presence of sinkholes, solution
cavities, and subterranean caverns. The unpredictable and catastrophic nature of subsidence in
these areas makes them difficult to develop as landfill sites (USEPA, 1993b). Given these
potential problems, EPA believes that thorough site characterization is required prior to siting any
landfill in a karst area.
In reporting many years of investigations of damages caused by sinkholes, Sowers (1996)
describes the principles of sinkhole formation, outlines investigation techniques, describes
measures available to stabilize foundations, cites a number of sinkhole cases, and offers
explanations for their causes. The most widespread and serious limestone engineering problem is
the development of a dome-shaped cavity in the overburden soil above a much smaller opening in
the rock below. The sudden collapse of the roof of such domes is responsible for virtually all of
the sinkhole failures that cause serious property damage and occasional loss of life. Water is the
enabling medium. Two conditions enable the cavities in the overburden to continue to enlarge:
continuous or repeated wetting of the overburden soil, accompanied by; downward flow or
percolation of ground water into an opening in the rock surface, and; a hydraulic connection with
water circulating in the rock cavities below (Sowers, 1996).
A large proportion of serious subsidence in areas underlain by solutioned limestone have
accompanied or have followed substantial lowering of the ground water table, and most
incidences of subsidence are induced by human activity such as water supply wells and quarry
construction dewatering. The decreased pore pressure in these areas reduces the bearing capacity
of the materials near the cavity and results in a sinkhole (Sowers, 1996).
Draft: June 1998
2-27
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In the 1970's and 1980's numerous sinkholes, 10 to 33 feet in diameter, formed in an open
undeveloped field near Frederick, Maryland, where no sinkholes were visible in 1970 aerial
photographs. These sinkholes were attributed to the combined influence of dewatering activities
in a large limestone quarry and increased storm water run-off associated with urban development.
The risk of large cover-collapse sinkholes was found to be greatest in innocuous-looking dry
valleys for the following four reasons:
• Because the size of the sinkhole is dependant on the thickness of the overburden,
deep sinkholes are likely to form where the overburden is deepest;
• Swales were found to be underlain by well-developed, fracture-controlled solution
cavities capable of transporting (piping) soil out of the area and allowing large
voids to grow rapidly;
• Swales often contain permeable alluvial soils that provide a pathway for perched
surface drainage to reach subsurface conduits; and
• Developers and civil engineers tend to regard swales as convenient and logical
places to locate detention ponds and to direct surface run-off (Boyer, 1997).
EPA has described methods for use in the characterization of subsurface structural conditions in
karst areas. These methods include subsurface drilling, sinkhole monitoring, geophysical
techniques, and remote sensing (USEPA, 1992 and 1993b). Methods to mitigate structural
problems in karst terrain include:
• control of ground water and surface water conditions to minimize the rate of
dissolution within near-surface limestone,
• excavation and/or over-compaction of loose soils overlying the limestone to
achieve the required stability (in areas where development of karst topography is
minor), and
• infilling of the voids with grout (in areas where the karst voids are relatively small
and limited in extent) (USEPA, 1993b).
Engineering solutions that try to compensate for weak geologic structures can be complex and
costly. Sowers reports methods for treatment of sinkhole areas to include excavation to the
narrowest point of the sinkhole bottom and plugging with concrete. Other methods for foundation
stabilization include grout injection, piles, caissons, reinforced concrete mat foundations, and other
complex solutions such as shafts to bedrock which, in many situations, is the only way to build
heavily loaded structures on solutioned limestone foundations (Sowers, 1996).
To ensure that foundation conditions are suitable when locating CKD landfills in karst areas, EPA
Draft: June 1998
2-28
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believes that a site-specific characterization is required to include consideration of the potential
for the presence of sinkholes or sinkhole-like subsurface conditions. This characterization should
be conducted in concert with the delineation of ground water flow pathways.5 Of particular
concern are those karst areas where the karst is considered mature. As described in Section 2.2.4
of this background document, of the 110 cement plant locations in the EPA data base, 18 are
located in mature karst areas where there is a potential for subsidence (sinkholes). EPA believes,
however, that special consideration for the stability of foundation material is warranted in all karst
areas because surficial evidence of sinkholes may not be present. EPA notes that relatively small
subsurface voids may result in sinkhole formation and the absence of large voids is insufficient
evidence that sinkholes are not likely to develop at a specific site.
2.2.2.2 Consequences of Contaminant Releases in Karst Areas
As described in Section 2.2.1, releases from CKD landfills, where conduit flow is present in the
subsurface, may travel rapidly in relatively undiluted form. Where conduit flow is continuous,
contaminants present in the release may travel a significant distance with potential for impacting
water supplies and surface water resources when discharged. Of the thirteen ground water
damage cases summarized in Table 2-1, there are at least four cases (Holnam, Inc., Mason City,
Iowa; Lehigh, Inc., Mason City, Iowa; Medusa Cement Co., Charlevoix, Michigan; and Signal
Mountain Cement Co., Chattanooga TN) in which the underlying karst aquifer played a significant
role in the off-site release of CKD constituents via the ground water pathway. In two another
cases, the presence of a karst aquifer is suspected to have contributed to the release (Penn-Dixie
Cement, Petrosky, MI, and Southdown, Inc., Fairborn, OH).
2.2.3 Dangers Posed by Disposal in Highly Fractured Media
Ground water in non-karst areas which are intensely fractured and faulted may be at risk from
uncontrolled CKD disposal practices. Saturated open fractures may form ground water systems
that could exhibit non-Darcy, conduit ground water flow. As in the case with karst aquifers,
ground water flow in fractured geologic media is commonly rapid and contaminant concentrations
may under go little attenuation relative to porous media. For example, at the Alamo Cement (San
Antonio, Texas) damage case site, natural fractures caused by faulting is suspected of having
contributed to the migration of CKD constituents into the surrounding environment. A total of 9
cement plants in the United States are estimated to be located in non-karst areas and have a
moderate to high potential to be underlain by ground water systems with conduit flow
characteristics (see Table 2-3). Many of these sites are estimated to have a moderate to high
potential for conduit ground water flow because of their proximity to major fault systems (e.g.,
San Andreas Fault System in California). Given the potential for ground water contamination at
sites with conduit-flow ground water systems, the Agency believes that ground water controls are
necessary to limit the potential for releases in areas with high fracture permeabilities. As
described in Chapter 5, performance and technical standards to protect ground water are being
5 See Section 7.1 of this background document for additional information on site characterization strategies.
Draft: June 1998
2-29
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proposed for new and actively managed CKD landfills.
2.2.4 Agency Evaluation of Potentially Karstic Areas and Areas of High Fracture
Permeability
The 1995 Regulatory Determination stated that about half of all the cement plants in the U.S. are
underlain by limestone formations in areas of karst landscape. This fact is noted to be a significant
qualification to the general findings of low or negligible risk from the ground water pathway risk
modeling result, which were described in the 1993 RTC and the 1994 NOD A.
Table 2-3 lists all the U.S. cement plants which are in operation6, the geographic location of each
plant, the potential presence of karst features, and the potential for conduit ground water flow at
these sites. This table was developed from a variety of data sources including topographic maps,
tectonic maps, formation correlation and bedrock maps, and water vulnerability maps. The
specific topographic maps which were examined are listed in Table 2-3 and other larger-scale
maps and references which were reviewed are listed in Table 2-4. The geologic factors examined
at each cement plant fall into four basic categories:
• The presence of underlying soluble rock such as limestone, dolomite, or other
carbonate rock formations. Carbonate rocks are often associated with karst
aquifers and conduit-type ground water flow regimes;
• The presence of physiographic and morphological features indicative of karst
hydrogeologic settings such as sinkholes, springs, caves, sinking streams, blind
valleys, pipes, and tubes;
• Tectonic features that indicate potential fractured bedrock (e.g., faults and
fractures); and
• Site-specific information obtained from damage cases.
6 Information on which cement plants are active is based on the 1995 PCA survey and 1997 information in EPA files on
hazardous waste burning status of cement kilns.
2-30
Draft: June 1998
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Table 2-3. Potential for Non-Darcy (conduit or fracture) Flow at U.S. Cement Manufacturing Facilities
Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of Tectonic Features or
Karstification (none/ Evidence of
immature/mature) Fractured Bedrock
(see Note 2)
Potential for Non-
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Note
Alamo Cement Co.
San Antonio
(Cementville)
TX
Longhorn, Schertz
Austin Chalk/Taylor
Marble
Yes: Carbonate
Immature
Faulting within 60 ft
ofCKD landfill
High
See damage case
summary Table 2-
Allentown Cement Co. Inc.
Blandon
PA
Temple
Jacksonburg
Formation, Limestone
Yes: Carbonate
Immature
Appalachian
Mountains
High
Armstrong Cement &
Supply Corp.
Cabot
PA
Worthington
Crenshaw Formation
Yes: Carbonate
Immature
Edge of a large uplift
(dome)
High
Ash Grove Cement Co.
Chanute
KS
Chanute
Paola Limestone
No
None
Fractured limestone
High
See note 4.
Ash Grove Cement Co.
Durkee
OR
Durkee
Volcanics
No: Springs
None
Highly faulted area
Medium
Ash Grove Cement Co.
Foreman
AR
Foreman
Marble/Chalk
Yes: Carbonate
Immature
Ouchita Orogeny
High
Ash Grove Cement Co.
Inkom
ID
Bonneville Peak,
Inkom
Cambrian Dolomite,
Marine Limestone
Yes: Carbonate
Immature
Portneuf and
Pocatello Mtn.
Ranges
High
Ash Grove Cement Co.
Louisville
NE
Springfield
Penn Aquifer
No
None
Low
Ash Grove Cement Co.
Montana City
MT
East Helena
Limestone,
Dolomite/Schist
Yes: Carbonate
Immature
Rocky Mountains
High
Ash Grove Cement Co.
Nephi
UT
Champlin Peak
Mississippian
Limestone
Yes: Carbonate
Immature
Medium
Ash Grove Cement Co.
Seattle
WA
South Seattle
Oligocene Marine
Strata
No
None
Low
Blue Circle Inc.
Atlanta
GA
Northwest Atlanta
No
None
Moderate Faulting in
Area
Low
Blue Circle Inc.
Calera
AL
Ozan, Montevallo
Limestone
Yes: Carbonate
Immature
Medium
Blue Circle Inc.
Harleyville
SC
Harleyville
Yes
Immature
Medium
Blue Circle Inc.
Ravena
NY
Ravena
Carbonate
Yes: Carbonate
Immature
Catskills
High
Blue Circle Inc.
Tulsa
OK
Mingo
Mississippian
Seminole Formation
Yes: Carbonate,
Springs
Mature (due to
presence of springs)
High
Calaveras Cement Co
Redding
CA
Project City
Paleozoic Limestone
No
None
Low
Calaveras Cement Co.
Tehachapi
CA
Tehachapi North,
South, and Northeast,
Paleozoic Limestone
No
None
Low
Calif. Portland Cement
Colton
CA
San Bernardino South
Limestone or
Dolomite
No
None
Tehachapi Valley
Low
Draft: June 1998
2-31
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Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of
Karstification (none/
immature/mature)
(see Note 2)
Tectonic Features or
Evidence of
Fractured Bedrock
Potential for Non- Note
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Calif. Portland Cement
Mojave
CA
Monolith
Paleozoic Limestone
No: Springs
None
San Andreas Fault
Area
Medium
Calif. Portland Cement
Rillito
AZ
Marana, Avra
No
None
San Andreas Fault
Area
Medium
Capitol Aggregates, Inc.
San Antonio
TX
Longhorn
Taylor Marble
Yes: Carbonate
Immature
Localized Faulting in
Vicinity
High
Capitol Cement Corporation
Martinsburg
WV
Martinsburg
Martinsburg
Formation Limestone
Yes: Carbonate
Immature
Appalachian
Mountains
High
Centex
Fernley
NV
Fernley East and
West, Two Tips,
Wadsw
NA
No: "Sink" to NE of None
facility
Sierra Nevada
Mountains
Low
Centex
Laramie
WY
Laramie
Alcova Limestone
(plant located over
Quaternary Alluvium)
Yes: Carbonate
Immature
Rocky Mountains
Medium
Centex
La Salle
IL
Lasalle
Limestone
No
None
Low
Continental Cement Co.,
Inc.
Hannibal
MO
Hannibal East
Mississippian
Limestone
Yes: Carbonate,
Caves
Mature (due to
presence of caves)
High
Dacotah Cement
Rapid City
SD
Rapid City West
Cretaceous Limestone
Yes: Carbonate,
springs
Mature (due to
presence of springs)
Uplift (Dome) -
Blackhills
High
Dixon-Marquette
Dixon
IL
Dixon East, Grand
Detour
Qrdovician Limestone
Yes: Carbonate rock,
Sinkholes
Mature
High
Dragon Products Co..
Thomaston
ME
Thomaston
Qrdovician Limestone
No
None
Low
Essroc Materials
Bessemer
PA
New Middletown,
Cambell, Bessemer
Allegheny Group
Limestone
Yes: Carbonate
Immature
Edge of large uplift
(dome)
High
Essroc Materials
Frederick
MD
Buckeystown, Point
of Rocks
Ordovician Grove
Limestone
Yes: Carbonate
Immature
Appalachian Orogeny
High
Essroc Materials
Logansport
IN
Clymers, Lucerne
Ordovician Limestone
Yes: Carbonate
beneath non-carbonate
overburden
Immature
Medium
Essroc Materials
Nazareth
PA
Nazareth
Allegheny Limestone?
Jacksonburg
Yes: Carbonate rock
and extensive
historical subsidence
and springs
Mature
Appalachian Orogeny
High
Draft: June 1998
2-32
-------
Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of Tectonic Features or
Karstification (none/ Evidence of
immature/mature) Fractured Bedrock
(see Note 2)
Potential for Non- Note
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Essroc Materials (Lone Star) Nazareth
PA
Nazareth
Allegheny Limestone? Yes: Carbonate rock
Jacksonburg and extensive
historical subsidence
and springs
Mature
Appalachian Orogeny
High
Essroc Materials
Speed
IN
Speed, Charlestown
Ordovician Limestone
Yes: Carbonate rock
with non-carbonate
overburden
Immature
High
Florida Crushed Stone
Brooksville
FL
NA
NA
Yes: area of historical
subsidence
Mature
High
Giant Cement Holding, Inc.
Harleyville
SC
Harleyville
NA
Yes: Carbonate
Immature
Medium
Giant Cement Holding
(Keystone)
Bath
PA
Catasuqua
Jacksonburg
Formation Limestone
Yes: Carbonate rock.
Extensive Historical
Subsidence
Mature
Appalachian Orogeny
High
Glens Falls Cement CO.,
Inc.
Glens Falls
NY
Hudson Falls, Glen
Falls
Carbonate
Yes: Carbonate rock
Immature
Appalachian orogeny
High
Holnam Inc.
Ada
OK
Ada
Penn. Francis
Formation Limestone
No
None
Low
Holnam Inc.
Artesia
MS
Crawford East and
West, Bent Oak,
Autecia
Demopolis Chalk &
Areola Limestone
Yes: Carbonate
Immature
Medium
Holnam Inc.
Clarksville
MO
Pleasant Hill West,
Clarksville
Mississippian
Limestone
Yes: Carbonate
Immature
Medium
Holnam Inc.
Dundee
MI
Dundee
NA (surface is lake
sediments)
Yes: Carbonate
Immature
Michigan Basin
High
Holnam Inc.
Florence
CO
Florence
Shale/limestone
Yes: Carbonate
Immature
Edge of Rocky
Mountain Foothills
Medium
Holnam Inc.
Fort Collins
CO
Laporte
Shale/limestone
Yes
Immature
Edge of Rocky
Mountain Foothills
Medium
Holnam Inc.
Holly Hill
SC
Holly Hill
Yes: Carbonate
Immature
Medium
Holnam Inc.
Mason City
IA
Mason City
Lime Creek
Formation
Limestone/dolomite
Yes: Carbonate
underneath non-
carbonate overburden
Immature
High See damage case
summary Table 2-
Holnam Inc.
Midlothian
TX
Venus, Midlothian,
Britton, Cedar Hill
Austin Chalk
Yes: Carbonate rock
Immature
Fractured limestone
High
Draft: June 1998
2-33
-------
Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of Tectonic Features or
Karstification (none/ Evidence of
immature/mature) Fractured Bedrock
(see Note 2)
Potential for Non- Note
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Holnarn Inc.
Morgan
UT
Devil's Slide, Henefer
Mississippian
Limestone
Yes: Carbonate
Immature
Medium
Holnarn Inc.
Seattle
WA
Seattle South
Olgicene Marine
Strata
No
None
Low
Low
Holnarn Inc.
Theodore
AL
Theodore, Hollingers
Island
Beach, Floodplain,
Terrace Deposits
(Sedimentation)
Yes: Fissures and
voids (karstic).
Unconsolidated
deposits
Mature
High
Holnarn Inc.
Three Forks
MT
Logan
Limestone/shale
Yes: Carbonate rock;
springs
Immature
Rocky Mountains
High
Independent Cement Corp.
Catskill
NY
Cementon
Carbonate
Yes
Immature
Catskill Mountains
High
Independent Cement Corp.
Hagerstown
MD
Hagerstown
Ordovician
Shenadoah Limestone
Yes: Carbonate
Immature
Appalachian Orogeny
High
Kaiser Cement Corp.
Permanente
CA
Cupertino
Tertiary Limestone
No
None
San Andreas Fault
area
Medium
Kosmos Cement Co.
Kosmosdale
KY
Kosmosdale
Quaternary Alluvium
Yes: Carbonate rock
Immature
Heavily Faulted
High
Kosmos Cement Co.
Pittsburgh
PA
Pittsburgh West,
Emsworth
Penn.
Sandstone/limestone
No
None
Edge of a Large Uplift Low
(Dome)
Lafarge Corporation
Alpena
MI
Alpena
Limestone bedrock,
surface is lake
sediment
No
None (but karst
features are found to
the north of the
facility)
Michigan Basin
Low See damage case
summary Table 2-
Lafarge Corporation
Buffalo
IA
Andalusia
Cedar Valley
Limestone
No
None
Low
Lafarge Corporation
Fredonia
KS
Fredonia
Limestone
No
None
Low
Lafarge Corporation
Grand Chain
IL
Joppa, Bandana
Sandstone/shale
Yes: Carbonate rock
Immature
Proximal to highly
faulted area
High
Lafarge Corporation
Paulding
OH
Paulding
Devonian - Columbus
and Delaware
Limestone
Yes: Carbonate rock
Immature
South edge of
Michigan Basin
Medium
Lafarge Corporation
Sugar Creek
MO
Liberty
Kansas City Group
Limestone
Yes: Carbonate
beneath non-carbonate
overburden
Immature
Medium
Lafarge Corporation
Whitehall
PA
Cementon, PA
Jacksonburg
Formation, Limestone
Yes: Carbonate with
historical subsidence
Mature
Appalachian
Mountains
High
Draft: June 1998
2-34
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Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of Tectonic Features or
Karstification (none/ Evidence of
immature/mature) Fractured Bedrock
(see Note 2)
Potential for Non- Note
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Lehigh Portland Cement
Leeds
AL
Leeds
Limestone
Yes: Carbonate rock;
historical subsidence;
springs
Mature
Highly faulted
mountainous region
(in the Chaba Valley)
High
Lehigh Portland Cement
Mason City
IA
Mason City
Lime Creek
Formation
Limestone/dolomite
Yes: Carbonate
beneath non-carbonate
overburden
Immature
Medium See damage case
summary Table 2-
Lehigh Portland Cement
Mitchell
IN
Bedford East,
Mitchell
Mississippian
Limestone
Yes: Carbonate rock
Immature
Medium
Lehigh Portland Cement
Union Bridge
MD
Union Bridge
NA
Yes: Carbonate
Immature
Appalachian Orogeny
High
Lehigh Portland Cement
Waco
TX
Lorena, South Bosque Austin Chalk
Yes: Carbonate
Immature
Medium
Lehigh Portland Cement
York
PA
West York
Kinzeras Formation
Limestone
Yes: Metamorphic
limestone, marble, and
dolostone
Immature
Appalachian Orogeny
High
Lone Star Industries
Cape Girardeau MO
Cape Girardeau
Ordovician Limestone
Yes: Carbonate, area
of historic subsidence
(Davies, etal, 1984)
Mature
Edge of highly faulted High
area
Lone Star Industries
Greencastle
IN
Cloverdale,
Greencastle,
Reelsville, Clinton
Falls
Mississippian
Limestone
Yes: Carbonate rock
beneath non-carbonate
overburden
Immature
Medium
Lone Star Industries
Oglesby
IL
Lasalle
Limestone
No
None
Low
Lone Star Industries
Pryor
OK
Salina
Mississippian -
Pitkin/Hindsville
Limestone
Yes: Carbonate
Immature
Medium
Lone Star Industries
Sweetwater
TX
Maryneal, Lake
Trammell
Glen Rose Limestone
Yes:
Carbonate/gypsum;
springs
Immature
Medium
Medusa Cement Co.
Charlevoix
MI
Charlevoix
Surface - lake
sediments
Yes: Carbonate
Mature (based on
damage case findings)
Michigan Basin
High See damage case
summary Table 2-
Medusa Cement Co.
Clinchfield
GA
Perry East
Limestone
Yes: Carbonate
beneath non-carbonate
overburden
Immature
Medium
Medusa Cement Co.
Demopolis
AL
Demopolis
Selma Chalk
Yes: Fissures, tubes,
and caves
Mature (based on
presence of karst
features)
High
Draft: June 1998
2-35
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Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of
Karstification (none/
immature/mature)
(see Note 2)
Tectonic Features or
Evidence of
Fractured Bedrock
Potential for Non-
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Note
Medusa Cement Co.
Wampum
PA
New Castle South
Allegheny Ordovician
Limestone
Yes: Carbonate rock
Immature
Edge of large uplift
(dome)
Medium
Mitsubishi Cement Corp.
Lucerne Valley
CA
NA
NA
No
None
Low
Monarch Cement Co.
Humboldt
KS
Humbolt
Limestone
No
None
Low
National Cement Co. Of
Alabama
Ragland
AL
Ragland
Shale/sandstone with
Coal
Yes: Carbonate Rock
Immature
Highly faulted
High
National Cement Co. Of
California
Lebec
CA
Lebec, La Liebre
Ranch
Paleozoic Limestone
No: Springs
None
San Andreas Rift
Zone
High (due to presence
of springs and
faulting)
North Texas Cement
Midlothian
TX
Venus, Midlothian,
Britton, Cedar Hill
Austin Chalk
Yes: Carbonate
Immature
Medium
Pennsuco Cement Co.
(Tarmac)
Medley
FL
Hialeah, Hialeah SW,
Pennsucola, Opa-1
Limestone
Yes: Carbonate rock
Immature
Medium
Phoenix Cement Co.
Clarkdale
AZ
Clarksdale
Limestone
Yes: Carbonate rock;
springs
Mature (due to
presence of springs)
High
Puerto Rico Cement Co.
Ponce
PR
Ponce, Penuelas
Ponce Limestone
No
None
Low
See note 5.
RC Cement Co. Inc.
(Heartland Cement Co.)
Independence
KS
Independence
Limestone/shale
Yes: Carbonate rock
Immature
High
RC Cement Co. Inc.
(Hercules Cement Co.)
Stockertown
PA
Wind Gap
Jacksonburg
Formation Limestone
Yes: Carbonate;
extensive historical
subsidence
Mature
Appalachian Orogeny
High
RC Cement Co. Inc. (River
Cement Co.)
Festus
MO
Selma
Ordovician Joachim
Dolomite
Yes: Carbonate
Immature
Localized faulting
High
RC Cement Co. Inc. (Signal
Mountain Cement Co.)
Chattanooga
TN
Chattanooga
Silurian Limestone
Yes: Carbonate
Mature (based on
damage case findings)
Appalachian
Mountains
High
See damage case
summary Table 2-
Rinker Portland Cement
Corp.
Miami
FL
Hilaleah Southwest
Oolitic/biodastic/otz
Sandstone/limestone
Yes
Immature
High
Rio Grande Cement Co.
(Holnam Inc.)
Tijeras
NM
Tijeras
Mississippian Madera
Limestone
Yes: Carbonate;
springs
Immature
Edge of Localized
Fault Area
High
Riverside Cement Co.
Oro Grande
CA
Victorville
NA
No
None
Low
Riverside Cement Co.
Riverside
CA
NA
Limestone or
Dolomite
No
None
San Andreas Fault
Area
Medium
RMC Lonestar - Santa Cruz
Davenport
CA
Davenport
Carboniferous
Limestone/Paleozoic
No
None
San Andreas Fault
Medium
Draft: June 1998
2-36
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Facility Name
City
State
Topographic Map
Name
Formation Name
and/or Lithology
Potential for Karst
Hydrogeologic
Setting (see Note 1)
Degree of Tectonic Features or
Karstification (none/ Evidence of
immature/mature) Fractured Bedrock
(see Note 2)
Potential for Non-
Darcy Flow (i.e.,
conduit or fracture
flow) (see Note 3)
Note
Roanoke Cement Co.
Cloverdale
VA
Catawba
Ordovician Limestone
Yes
Immature
Medium
Royal Cement Co., Inc.
Logandale
NV
NA
No
None
Low
San Juan Cement Co.
Dorado
PR
Vega Alta
Limestone
No
None
Low
See note 6
Southdown
Brooksville
FL
Brooksville
Limestone
Yes: Area of
historical subsidence
Mature
High
Southdown
Fairbom
OH
Fairbom, Yellow
Springs
Devonian - Columbus
and Delaware
Limestone
Yes: Carbonate rock
Immature
High (based on
damage case)
See damage case
summary Table 2-1.
Southdown
Knoxville
TN
John Sevier
Ordovician Limestone
Yes: Carbonate
Immature
Appalachian
Mountains
High
Southdown
Lyons
CO
Hygiene
Shale/limestone
Yes
Immature
Edge of Rocky
Mountain Foothills
High
Southdown
Odessa
TX
Penwell, Douro
Glen Rose Limestone
Yes: Carbonate rock;
karst-like topographic
features; fissures and
voids
Mature
High
Southdown
Victorville
CA
Fairview Valley,
Stoddard Well, Apple
Valley, Turtle Valley
Carboniferous marine
limestone
No
None
Fairview Valley/San
Andreas Fault
Medium
Sunbelt Cement Corp.
(Lafarge Corporation)
New Braunfels
TX
New Braunfels West
Anacacho Limestone
Yes: Area is
underlain by Edwards
Aquifer
Mature
High
Texas Industries
Midlothian
TX
Venus
Austin Chalk
Yes: Carbonate
Immature
Medium
See damage case
summary Table 2-1.
Texas Industries
(TXI Cement)
New Braunfels
TX
Geronimo, New
Braunfels East
Taylor Marble
Yes: Carbonate
Immature
Highly Faulted Area
Medium
Texas-Lehigh Cement Co.
Buda
TX
Buda
Austin Chalk
Yes: Carbonate
Immature
Fractured Limestone
Medium
Draft: June 1998
2-37
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Facility Name City State Topographic Map Formation Name Potential for Karst Degree of Tectonic Features or Potential for Non- Note
Name and/or Lithology Hydrogeologic Karstification (none/ Evidence of Darcy Flow (i.e.,
Setting (see Note 1) immature/mature) Fractured Bedrock conduit or fracture
(see Note 2) flow) (see Note 3)
Notes to Table 2-3:
"Yes" indicates subterranean karst features are present in the vicinity of the cement plant, as indicated on karst or geologic maps listed in Table 2-4. Karst hydrogeologic settings can be found in areas of
limestone, dolomite or other soluble rock formations (e.g., carbonate rocks). Characteristic physiographic and morphological features that can be indicative of karst hydrogeologic settings include sinkholes,
springs, caves, sinking streams, blind valleys, pipes, and tubes. Geologic and physiographic information obtained from topographic maps cited in the table and other references identified in Table 2-4.
2. "Mature" karst includes those areas in which extensive historical subsidence has occurred (unless otherwise noted).
3. "Non-Darcy Flow" refers to ground water flow rates that exceed the upper limit of Darcy's Law. Such flow rates are common in rock formations such as karstic limestones and dolomites, and cavernous
volcanics (Freeze and Cherry, 1979). "Potential for Non-Darcy (i.e., conduit or fracture) flow" was determined based on the presence of karst features, degree of karstification, and tectonic features in the
vicinity of each facility listed. "High" potential was assigned to areas with mature karst features or a combination of immature karst features, highly fractured media, or other "pseudokarst" features. In the
absence of site-specific information, "Medium" was assigned to areas with either karst features or fracture flow conditions. "Low" was assigned to areas with no karst features or fractured bedrock.
Ash Grove, Chanute, KS is underlain by the fractured Paola Limestone unit. Ground water flow through fractured bedrock has been documented as causative in damage cases for the Ash Grove Chanute, KS
facility. See Section 2.2 of this background document.
5. Source: Krushensky, Richard D. and Watson H. Monroe, 1975, Geologic Map of the Ponce Quadrangle, Puerto Rico, USGS Map 1-863.
6. San Juan Cement, Dorado, PR is located near the north coast limestone region of Puerto Rico which is highly karstified. However, local conditions are not believed to be karstic. Source: review of Mapa de
Carreteras Estatales de Puerto Rico (1978), Geologic Map of Puerto Rico (1933), map showing limestone areas and karst land forms in Puerto Rico (1976)
NA = information not available or not determined
Draft: June 1998
2-38
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Table 2-4. State-Specific Maps and Other References Used for Research Concerning
Potential Ground Water Flow at Active Cement Plants
Alabama
•
•
•
Geologic Map of Alabama (1926)
Groundwater Availability in Jefferson County, Alabama (1990)
State of Alabama and Part of Georgia Coal Fields and producing Districts
Arizona
•
•
•
•
•
Geologic Map and Sections of the ASO Quadrangle, Pima County, Arizona (1946)
Geologic Map of Arizona (1969)
Geologic Map of the Bagdad Area, Yavapi County, Arizona (1945)
Geologic Sections of the Bagdad Area, Yavapi County, Arizona (1945)
Sample Sites, Mines, Prospects, and Mining Claims in the Rincon Wilderness Study Area, Pima
County, Arizona (1977)
Arkansas
•
•
Geologic Map of Arkansas (1976)
Geology of Arkansas, Surface and Below Surface (1941)
California
•
•
•
•
•
•
•
•
Geologic Map and Sections of the Eastern Part of the Clark Mountain Range, San Bernardino
County, California (1967)
Geologic Map of California (1938 and 1977)
Geologic Map of California - San Bernardino sheet (1967)
Geologic Map of California - Santa Cruz sheet (1958)
Geologic Map of Shasta County, CA (1972)
Geologic Map of Shasta Valley, CA showing location of wells and springs (1954)
Geologic Map of the Kreyenhagen Hills-Sunflower (McLure) Valley Area, Fresno, Kern, Kings,
and Monterey Counties, CA (1992)
Geologic Map of the Redding Quadrangle, Shasta County, CA (1965)
Colorado
•
•
Geologic Map of Colorado (1975)
Map of Colorado Showing Coal Bearing Regions and Fields (1959)
Florida
•
•
•
•
Environmental Geology Series - Miami sheet (1956)
Geologic Map of Florida (1981)
Mineral Resources of Hernando County, Florida (1988)
Occurrence of Beds of Low Hydraulic Conductivity in Surficial Deposits of Florida (1984)
Georgia
•
•
•
Geologic Map of Georgia (1939)
Georgia Groundwater (1963)
Water Resources Investigation in Georgia (1978)
Indiana
•
•
Map of Indiana showing Locations of Coal and Industrial Minerals Operation (1984)
Quaternary Geologic Map of Indiana (1989)
Iowa
•
Geologic Map of Iowa (1969)
Kansas
•
Geologic Map of Kansas (1964)
Kentucky
•
Geologic Map of Kentucky (1988)
Maine
•
Preliminary Geologic Map of Maine (1967)
Draft: June 1998
2-39
-------
Maryland
• Geologic Map of Frederick County (1938)
• Map of Maryland Showing all Geological Formations and Agricultural Soils (1907)
Michigan
• Map of the Surface Formations of the Southern Peninsula of Michigan (1955)
Mississippi
• Geologic Map of Mississippi (1945)
Missouri
• Geological Map of Missouri (1979)
• Groundwater Areas of Missouri (1962)
Montana
• Geologic Map of Montana
Nebraska
• Geologic Bedrock Map of Nebraska (1986)
• Groundwater Vulnerability to Contamination in Nebraska Using the Drastic Method (1991)
Nevada
• Geologic Map Index of Nevada (1955-1970)
• One Million Scale Set Geologic Map of Nevada (1977)
New Mexico
• Geologic Map of New Mexico (1965)
New York
• Geology of the Capital District (Albany and Vicinity) (1928)
• Groundwater in New York (1964)
Ohio
• A geological Map of Ohio (1909)
Oklahoma
• Geologic Map of Oklahoma (1954)
• Reconnaissance of the Water Resources of the Tulsa Quadrangle, Northeastern Oklahoma (1971)
Oregon
• Geologic Map of Oregon (1991)
Pennsylvania
• Geologic Map of Pennsylvania (1980)
Puerto Rico
• Geologic Map of Southeastern Puerto Rico (1967)
South Dakota
• Geologic Map of South Dakota (1953)
Tennessee
• Geologic Map of Tennessee (1933)
Texas
• Geologic Map of Texas (1937)
Utah
• Geologic map of Utah (1980)
Virginia
• Geologic Map of Virginia (1993)
Washington
• State of Washington Preliminary Geologic Map (1936)
West Virginia
• Geologic Map of West Virginia
Wyoming
I Geologic Map of Wyoming (1980)
Draft: June 1998 2-40
-------
Other References
Basement Rock Map of the United States, 1968.
Childs, Orlo E., Correlation of Stratigraphic Units of North America - COSUNA, The American Association of
Petroleum Geologists Bulletin, Vol. 69, No. 2, February 1985.
Coal Map of North America, 1988.
Davies, W.E., J.H. Simpson, G.C. Ohlmacher, W.S. Kirk, and E.G. Newton, 1984. Engineering Aspects ofKarst,
Scale 1:7,500,000. U.S. Geological Survey, Map no. 38077-AW-NA-07M-00.
Generalized Tectonic Map of the United States, 1972.
Geologic Map of the United States, 1974.
Todd, D.KGround-Water Resources of the United States. Berkeley, CA; Premier Press, 1983.
United States Geological Survey, National Atlas of the United States - Surficial Geology, 1979.
United States Geological Survey, State Water-Data Reports: Hydrologic Records of the United States Water Years
1990, 1991, and 1992. Open-File Report 93-626.
Information on the presence of karst features such as sinkholes, springs, sinking streams, caves,
and historical subsidence combined with other site-specific knowledge was used to indicate the
potential for karst hydrogeologic settings and to indicate the relative maturity of the karst if
found. The lithology was identified from USGS maps and other sources identified in Table 2-4.
The presence of a soluble rock formation such as limestone (as indicated on geologic maps) is an
indicator of a potential karst area. Topographic and karst maps were reviewed to identify surface
geomorphologies which may suggest the presence of karst-like features including sinkholes (local
zones of instability in karst terrain may result in ground collapse and subsidence), sinking streams,
caves, large springs, blind valleys, pipes and tubes. The specific topographic maps used for this
analysis are identified for each facility in Table 2-3. Karst maps (such as Engineering Aspects of
Karst (Davies et al., 1984)) and State-specific geologic maps listed in Table 2-4 were reviewed to
identify karst areas and tectonic features.
Areas with extensive historical subsidence or other obvious karst features such as caves, springs,
and sinkholes are considered "mature" karst for the purpose of this analysis. Areas identified as
karst, but without the characteristic morphological features of karst, are considered "immature"
karst for the purpose of this analysis. Tectonic features were also identified to evaluate the
potential for non-Darcy flow in the site vicinity. In the absence of site-specific information, such
as the damage case information (Section 2-1), sites which are not located in either karst terrain or
near tectonic features were assumed to have a "low" potential for non-Darcy ground water flow
characteristics (i.e. conduit or fracture flow systems). Sites located in either fractured or karst
terrain (but not both) were estimated to have a "medium" potential for non-Darcy ground water
flow. Sites located in both fractured and karst terrain or were found to overlie mature karst
Draft: June 1998
2-41
-------
aquifers were estimated to have a "high" potential for non-Darcy ground water flow.
Of the 110 cement plants, 79 are located in areas characterized by karst hydrogeology. Of these,
20 are considered in mature karst settings. The Agency believes that there is a potential for
conduit ground water flow to occur at sites located in karst terrain and that CKD disposal sites
found to be in karst areas should be subject to new standards for site characterization and landfill
design (see Section 5 of this TBD). In addition, 9 cement plants sites not located in karst areas
have a high or moderate potential for non-Darcy, conduit flow ground water systems due to
fractured bedrock aquifers.
2.3 Damage to Wetlands, Lakes, and Streams Caused by Releases from CKD
Management Units
Disposal of CKD at and near sensitive aquatic environments, including wetlands, lakes, and other
surface water bodies, has resulted in significant ecological and water quality damages. There are
at least six known CKD disposal sites where damage to wetlands and surface water bodies has
been demonstrated or the pH of the surface water exceeded the RCRA corrosivity criteria for
hazardous waste (12.5 SU). The factors which have contributed to release of CKD constituents
to these sensitive environments are summarized in Table 2-6 and include:
• Lack of an engineered cover or bottom liner in the CKD disposal unit (all six
cases),
• Waste CKD in contact with shallow ground water with migration of CKD
constituents in ground water to nearby seeps and streams (in at least 5 cases), and
• Stormwater run-off transporting CKD from the disposal unit to nearby streams or
lakes (in at least 4 cases), and
• Surface water run-off and lake shoreline erosion causing transport of CKD, CKD
constituents, and other debris from the waste management unit to the surface
water body (National Gypsum site in Alpena, Michigan).
Damages to wetlands and streams from CKD disposal activities are examined in Section 2.3.1.
Section 2.3.2 describes the damages that occurred to Lake Huron's Thunder Bay and Whitefish
Bay as a result of CKD disposal by the National Gypsum Company in Alpena, Michigan. The
Agency's evaluation of CKD disposal in wetlands or adjacent to surface water bodies is
summarized in Section 2.3.3.
Draft: June 1998
2-42
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Table 2-5. Factors Contributing to Release of CKD Constituents to Wetlands and Surface
Water
Damage Case,
City, State
(Reference)
Covered
Landfill
at Time of
Release?
Bottom
Liner
Present?
CKD In Contact
with Ground
Water or Disposed
Below Natural
Water Table?
CKD Release
Mechanism?
Impacts to
Wetlands or
Surface Water?
Holnam, Inc.,
Mason City, IA
(USEPA, 1993a
and 1997b)
No
No
CKD disposed of in a
former quarry which
later filled up with rain
and ground water
Shallow ground water
transport and surface
runoff from disposal
areas to seeps and
Calmus Creek
9/86 fish kill in
Calmus Creek;
Aquatic community
structure dominated by
tolerant species
Lehigh, Inc.,
Mason City, IA
(USEPA ,1993a
and 1997c)
No
No
CKD disposed of in
former quarries which
later filled up with rain
and ground water
Shallow ground water
transport and surface
runoff from disposal
areas to seeps and
Calmus Creek
9/86 fish kill in
Calmus Creek;
Aquatic community
structure dominated by
tolerant species
Signal Mountain
Cement Co.,
Chattanooga TN
(USEPA, 1997a)
No
No
CKD disposed of in
water-filled quarry
cavities
Shallow ground water
transport and surface
runoff from disposal
areas to seeps and
creeks
Releases with a pH
above 12.5 to an
unnamed tributary of
the Tennessee River;
tributary is abiotic
Southdown, Inc.,
Fairborn, OH
(USEPA, 1993a)
Unspecified
No
CKD was landfilled in
unlined quarries,
Shallow ground water
transport from disposal
areas to seeps and
creeks
Seeps and surface
water with pH up to
13.6
Lehigh Portland
Cement Co.,
Metaline Falls
(USEPA, 1997d)
No
No
Lowermost portion of
CKD pile below water
table
Shallow ground water
transport from disposal
area to seeps and
drainage channels
Seeps and surface
water with pH up to
14 downgradient of
the disposal area
National Gypsum
Co., Alpena, MI
(USEPA, 1997a)
No
No
Unspecified
Wave erosion from
Lake Huron and
surface run-off to
Lake Huron
Near shore aquatic
community dominated
by tolerant species;
lake sediments failed
toxicity tests
Summary
At least 5
cases
involve
uncovered
CKD
waste units
All 6 cases
had no
bottom
liner
At least 5 cases
where CKD was in
direct contact with
ground water
Ground water
transport (5 cases);
Surface water run-
off (4 cases); Lake
erosion (1 case)
Seep/Surface water
pH >12.5 (3 cases);
Altered aquatic
community structure
(4 cases)
Draft: June 1998
2-43
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2.3.1 Wetland and Stream Damage From CKD Disposal
The close proximity of the water table to the ground surface in and near wetlands and streams and
the mobility of CKD constituents in ground water make these environments susceptible to
contamination from unengineered CKD disposal units. Contact of waste CKD with ground water
was noted at five of the sites listed in Table 2-6. At the Fairborn, Ohio; Chattanooga, Tennessee;
and Mason City, Iowa sites, CKD was disposed of in quarries, which subsequently became filled
with water. The ground water table at the Metaline Falls, Washington site was in contact with the
CKD pile. At these sites, the migration of ground water, which came in contact CKD,
transported CKD constituents to nearby seeps and streams. As shown in Table 2-6, the pH of
seeps and surface water near the Metaline Falls, Washington; Chattanooga, Tennessee; and
Fairborn, Ohio sites often exceeded the RCRA corrosivity criteria of 12.5 SU for hazardous
waste. In addition, at the Fairborn, Ohio site, metals such as arsenic, cadmium, chromium, iron,
lead, nickel, and selenium were identified in surface water and shallow ground water above
drinking water standards (USEPA, 1993 a).
Ecological degradation of Calmus Creek, including a fish kill in September 1986, has been
documented near and downgradient of the Lehigh and Holnam facilities in Mason City, Iowa.
Aquatic habitat evaluations of Calmus Creek in 1984, 1989 and 1992, indicated that populations
of organisms with external gills and benthic taxa were fewer in number downstream of the cement
facilities relative to the upstream stations. Species with external gills are sensitive to suspended
particulate matter as this matter interferes with the organism's respiration. The four most
abundant species collected (black bullhead, central stoneroller, green sunfish, white sucker) are
among the species most tolerant of high turbidity, dissolved oxygen and flow extremes,
agricultural siltation, and industrial and domestic pollution. Excessive sedimentation in Calmus
Creek was a probable cause for the lack of smallmouth bass. Sedimentation has a profound effect
on smallmouth bass habitat, because sedimentation covers suitable spawning areas, suffocates
eggs of larval fish, or inhibits sight-feeding activities of bass fry (USEPA, 1997b).
2.3.2 Lake Damage From CKD Disposal
An old, inactive CKD disposal pile, created and owned by the National Gypsum Company is
located along the shore of Lake Huron's Thunder Bay in Alpena, Michigan. During a site visit in
March 1993, inspectors from the Michigan Department of Natural Resources (MDNR) reported
that CKD from the pile was washing into a large erosion ditch (one meter wide by three meters
deep) leading to Lake Huron. Other debris, including airbags, drums, kiln brick, and
miscellaneous materials co-disposed with the CKD also were being transported in the ditch to the
lake. In addition, waves from the lake were reported to be actively eroding the pile along six to
nine meter high banks on the south end of the shoreline.
Soil and surface water samples obtained from the pile near the shore of Lake Huron showed
evidence of CKD contamination. Arsenic, selenium, lead, and zinc concentrations in grab samples
of soil from the beach and upslope from the shore on the CKD pile exceeded State soil cleanup
Draft: June 1998
2-44
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default values. Surface water samples from the erosion ditch and nearby Lake Huron also contain
levels of arsenic and lead that exceed State standards.
In July and August 1996, EPA Region V collected data on the fish community structure and
function, habitat, and sediment in Thunder Bay and Whitefish Bay. Whitefish Bay is a small
embayment north of the CKD pile and receives discharge from the site via an outfall. These data
indicate that the ecosystems of both bays have been altered by the filling in of interstitial spaces in
the sediment and by the blanketing of sediments by eroded, discharged, and wind-blown ash
materials. The absence of trout-perch, burbot, and large smallmouth bass near the CKD pile is
contrasted with the presence of tolerant species such as spottail shiner, carp, and large proportion
of younger individual smallmouth bass. The dominance of carp near the Lafarge outfall and deep
deposits of ash have precluded the use of Whitefish Bay by the representative fauna of Lake
Huron and Thunder Bay. Pore water and bulk sediment toxicity test results from Thunder Bay
and Whitefish Bay showed chronic toxicity to Ceriodaphnia. Hyallela. and Chironomus (Simon,
1996). The toxicity test results showed toxicity in five out of seven samples with Chironomus. in
four out of seven samples with Hyallela. and in two out of seven samples with Ceriodaphnia.
The furthest sample from the CKD pile was located about 1000 feet (300 meters) from the CKD
pile and indicated toxic conditions with a Chironomus survival rate of 29% (Simon, 1998).
Additional EPA Region V observations of the environmental damage in the vicinity of the CKD
pile include the following:
Habitat has been severely altered by the filling in of emergent wetlands, cementing
of natural rock substrates, and the washing and erosion of the CKD Pile. The
CKD pile appears to have filled in a portion of a wetland near Whitefish Bay and
has formed an "unnatural" backwater composed of CKD briquettes. The washing
and erosion of the pile has cemented natural substrates and caused a significant
portion of the bottom to appear as an underwater cement desert. A milky white
haze from wave action has reduced the littoral zone community along the
immediate escarpment of the CKD pile. A measurement of pH from water samples
showed elevated levels; however, these did not exceed State of Michigan water
quality standards (Simon, 1996).
2.3.3 Agency Evaluation of CKD Disposal in Wetlands and Adjacent to Surface Water
The Agency places a high priority on protecting wetlands and surface water bodies from sources
of pollution including CKD waste disposal sites. Based on a review of the CKD disposal site
damage cases, EPA has determined that wetlands and surface water bodies have been adversely
impacted by CKD disposal in and near these environments. To protect these sensitive
environments, EPA is proposing a ban against CKD disposal below the water table and is
proposing special design and operational requirements for CKDLF units located in the 100-year
floodplain and in wetlands. Good engineering practices require that CKDLF units should be
located away from lakes and streams in order to prevent surface water from eroding into the
Draft: June 1998
2-45
-------
disposal unit and releasing CKD constituents into the environment. Interim and final landfill
covers are critical to prevent rainwater infiltration into the CKD waste management unit and to
prevent the CKD from contacting stormwater run-off
As stated in the Agency's Regulatory Determination (60 FR 7366), the Clean Water Act provides
sufficient authority to control risks to surface water associated with releases from CKD waste
management sites. The Clean Water Act has a number of regulatory mechanisms to protect
surface waters including effluent guideline regulations, National Pollutant Discharge Elimination
System (NPDES) permits, water quality standards, and storm water permits. EPA's multisector
stormwater general permit contains limits to control effluent discharges specific to the cement
industry (among other industries) and requires each plant to develop facility-specific pollution
prevention plans and demonstrate best management practices. These measures, when
implemented at CKD disposal sites, are expected to minimize the potential for contact between
stormwater run-off and CKD or else remove CKD before the stormwater is discharged.
2.4 EPA Conclusions Regarding Potential Impacts of CKD to Ground Water
In the Regulatory Determination (60 FR 7366), EPA concluded that additional control of CKD is
warranted in order to protect the public from human health risks and to prevent environmental
damage. EPA proposed to develop a tailored set of standards for CKD that controls releases to
ground water under Subtitle C of RCRA. As discussed in Section 2.1, the existence of at least
thirteen CKD disposal sites with ground water contamination indicates that current practices are
inadequate to limit contaminant releases. The damage cases show that there is an increased risk
to ground water when CKD is land-disposed in karst environments, in quarries below the natural
water table, and/or near wetlands and surface water features. In each of these damage cases,
water came in contact with CKD resulting in development of alkaline solutions which mobilized
metals into the environment. Factors which have contributed the release of CKD contaminants
from the waste management unit to ground water include disposal of CKD below the water table
in uncovered, unlined pits, and/or with no leachate collection. Based on these damage case
findings, EPA has determined that current CKD waste management practices are inadequate and
that it is necessary to establish performances standards and default technical design standards for
CKD landfills. Proposed CKD landfill design standards are presented in Chapter 5.
Draft: June 1998
2-46
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References
Boyer, Bruce W., 1997. "Sinkholes, Soils, Fractures, and Drainage: Interstate 70 Near Frederick,
Maryland". In Environmental & Engineering Geoscience. Joint publication of the
Association of Engineering Geologist and the Geological Society of America. Volume III,
Number 4. Winter 1997.
Dames and Moore, 1993. Addendum Preliminary Site Characterization Report. Prepared for
Lehigh Portland Cement Company, Metaline Falls, Washington. October 5, 1993.
Davies, W.E., J.H. Simpson, G.C. Ohlmacher, W.S. Kirk, and E.G. Newton, 1984. Engineering
Aspects of Karst. Scale 1:7,500,000. U.S. Geological Survey. Map No. 38077-AW-NA-
07M-00.
Freeze, R.A, and J. A. Cherry, 1979. Groundwater. Prentice-Hall, Inc., Englewood Cliffs, NJ.
Mull, D.S., T.D. Liebermann, J.L. Smoot, and L.H. Woosley, Jr., 1988. Application of Dye-
Tracing Techniques for Determining Solute-Transport Characteristics of Ground Water
in Karst Terrains, U.S. Environmental Protection Agency Report, EPA 904/6-88-001.
Ohio Environmental Protection Agency (Ohio EPA), 1993. Fact Sheet: Southwestern Portland
Cement Company — Landfill No. 6, Fairborn, Ohio. March 1993
Ohio Environmental Protection Agency (Ohio EPA), 1992. Director's Findings and Order in the
Matter of Southdown, Inc, 506 East Xenia Drive, Fairborn, Ohio.
Ohio Environmental Protection Agency (Ohio EPA), 1991. Memo from Louise T. Snyder,
DWQOA, SDWO on the Southwestern Portland Cement facility, Landfill #1. September
9, 1991.
Personal communication with Dr. Thomas Simon, 1998. EPA Region V, Water Enforcement &
Compliance Assurance Branch, WC-15J. January 20, 1996.
Portland Cement Association (PCA), 1996. U.S. and Canadian Portland Cement Industry: Plant
Information Summary.
RMT, Inc. (RMT), 1996. Remedial Investigation (Phase II) Report, Final, Volume I of II.
Prepared for Medusa Cement Company, Charlevoix, MI. Prepared by RMT, Inc., Ann
Arbor, MI. August 1996.
Science Applications International Corporation (SAIC), 1996. Untitled memorandum to Bill
Schoenborn, USEPA from Jack Mozingo, SAIC. EPA Contract 68-W4-0030, WA 105,
Task 7, QRT 4. SAIC Project 01-0857-07-4401-074. June 4, 1996.
Draft: June 1998
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Simon, T., 1996. "Assessment of Field Data from Thunder Bay: Environmental Harm". EPA
Region V, Water Enforcement & Compliance Assurance Branch, WC-15J. October, 15
1996.
Smith, J.H., 1997. "Regulatory Definition of Karst Terrane and Groundwater Assessment and
Sampling Guidelines for Karst Aquifers, Draft Final Rule for Cement Kiln Dust Landfills".
Memorandum from James Smith, Environmental Scientist, RCRA Programs Branch, EPA
Region IV, to William Schoenborn, Environmental Scientist, Municipal and Industrial
Solid Waste Division. November 10, 1997.
Sowers, G.F., 1996. "Building on Sinkholes, Design and Construction of Foundations in Karst
Terrain". American Society of Civil Engineers, ASCE Press. New York 1996.
U.S. Environmental Protection Agency (USEPA), 1997a. Technical Background Document -
Additional Documented and Potential Damages from the Management of Cement Kiln
Dust. Office of Solid Waste. September 3, 1997.
U.S. Environmental Protection Agency (USEPA), 1997b. CKD Waste Releases and
Environmental Effects Summary, Holnam Incorporated, Mason City Iowa. Prepared
under EPA Contract No. 68-W4-0030, Work Assignment 215, Task 13. [final date]
U.S. Environmental Protection Agency (USEPA), 1997c. CKD Waste Releases and
Environmental Effects Summary, Lehigh Portland Cement Company, Mason City Iowa.
Prepared under EPA Contract No. 68-W4-0030, Work Assignment 215, Task 13. [final
date]
U.S. Environmental Protection Agency (USEPA), 1997d. Detailed Summary of CKD Disposal
at Lehigh Portland Cement Company, Metaline Falls, Washington - Final Report.
Prepared under EPA Contract No. 68-W4-0030, Work Assignment 215, Task 12. April
25, 1997.
U.S. Environmental Protection Agency (USEPA), 1997e. CKD Wastes Releases and
Environmental Effects Summary: Portland Cement Superfund Site, Salt Lake City, Utah -
Final Report. Prepared under EPA Contract No. 68-W4-0030, Work Assignment 215,
Task 13. March 14, 1997.
U.S. Environmental Protection Agency (USEPA), 1995. 40 CFRPart 261 Regulatory
Determination on Cement Kiln Dust: Final Rule. Federal Register, Vol. 60 No. 25
(Tuesday, February 7, 1995).
U.S. Environmental Protection Agency (USEPA), 1994. Notice of Data Availability, Human
Health and Environmental Risk Assessment in Support of the Report to Congress on
Cement Kiln Dust. EPA Office of Solid Waste. August 31, 1994, Revised per Federal
Draft: June 1998
2-48
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Register Notice of October 11, 1994.
U.S. Environmental Protection Agency (USEPA), 1993a. Report to Congress on Cement Kiln
Dust, Volume II Methods and Findings. EPA Office of Solid Waste. December 1993.
U.S. Environmental Protection Agency (USEPA), 1993b. Solid Waste Disposal Facility
Criteria, 40 CFR Part 258, Technical Manual. EPA Office of Solid Waste. November
1993.
U.S. Environmental Protection Agency (USEPA), 1992. RCRA Ground-Water Monitoring:
Draft Technical Guidance. Office of Solid Waste, Washington, DC EPA/530/R-93/001,
NTIS PB 93-139350
U.S. Environmental Protection Agency (USEPA), Undated. "Research and Development: Flow
and Transport Modeling in Karst Aquifers—A Status Report." EPA Environmental
Research Laboratory, Athens, GA.
Draft: June 1998
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Chapter 3: Evaluation of Options for Technical Design Criteria for CKDLF Units
3.1 Identification and Evaluation of Options for Technical Design Standard
Based on observed environmental damages to ground water resources at CKD disposal sites and
the vulnerability of ground water in karst terrain, EPA recognized the need to improve CKD
waste management practices and prevent releases of hazardous constituents from CKD into the
environment. In response, EPA has evaluated a range of possible landfill design configurations
against a range of performance standards. Generally, to evaluate the performance of landfill
designs for both Subtitle D and Subtitle C landfills, the EPA uses modeling to first predict the
leakage of constituents from the base of the landfill, then to predict ground-water flow and
transport of these constituents to a point of concern (POC). If concentrations of constituents of
concern are found to be below a specified level of concern (generally, the established maximum
contaminant level (MCL) for that constituent), a design is considered to meet the performance
standard.
This approach, however, is not appropriate for those CKD landfills that are located in karst
hydrogeologic settings. Most ground-water flow models are based on Darcian equations of flow
that assume flow through a porous media. Flow through large conduits, such as occurs in karst
terrains, is not Darcian flow. Therefore, most ground-water models cannot be used to effectively
predict flow, dilution, or attenuation in karst terrains. A few ground-water models have been
developed to predict dilution and attenuation in karst terrains, but they are highly dependent on
site specific factors such as the maturity of karst or the direction of the flow through the
subsurface conduits. This kind of detailed site-specific information is not available to the Agency
for the CKD landfill sites under consideration. In addition, a site-specific modeling approach is
not appropriate for evaluating performance of a landfill design that may be used in many different
hydrogeologic settings.
Based on these limitations, the EPA determined that, for those CKD landfills located in karst
terrains, the predicted leakage rate for a particular landfill design would be used to determine the
degree of protectiveness of that design. Because contaminant releases to karst aquifers can travel
in ground water long distances in a relatively undiluted form, landfill leakage rates can be used as
an indicator of landfill performance relative to a standard. The EPA used the Hydrologic
Evaluation of Landfill Performance (HELP) model (Schroeder, et. al., 1994) to predict leakage
rates for several landfill designs, including designs derived from the CKD industry proposal, as
well as default Subtitle D and Subtitle C landfill designs. The remaining sections of this chapter
discuss the development of the particular designs modeled (Section 3.2), an overview of the
HELP model (Section 3.3), and the modeling results (Section 3.4).
For CKD landfills located in non-karst terrains, the EPA coupled the HELP model results
discussed in this chapter with a subsurface ground water flow model (MULTIMED) to predict
potential dilution and attenuation in the subsurface. The results of this effort are discussed in
Draft: June 1998
3-1
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Chapter 4 of this background document.
3.2 Landfill Design Configurations
As part of this analysis, EPA evaluated a total of five prospective landfill liner design
configurations. These design configurations included a "baseline" CKD landfill (to represent an
uncontrolled CKD landfill similar to current practices); two configurations intermediate between a
baseline and the Subtitle D design; a Subtitle D municipal solid waste design (including a
composite liner with leachate collection); and a full Subtitle C hazardous waste design (including a
double liner with leachate collection/detection). The two designs between the baseline and the
Subtitle D design are based on designs proposed by the cement industry (Alben, et. al., 1993).
EPA reviewed the designs proposed by the industry and determined that changes to these designs
were necessary, in part because the HELP model predicted unrealistic flow at the surface of these
designs (ICF, 1995), and in part to reflect more appropriate engineering practices. The
intermediate designs were included in the current evaluation to accommodate industry concerns
while still reflecting better design practices. It is recognized that other designs may meet the
proposed performance standard for CKD landfills, depending upon site specific conditions. The
configurations of the landfill designs evaluated by EPA are summarized in Table 3-1 and discussed
in the following sections.
3.2.1 Cement Industry's "Contingent Management Practices" for CKD
In 1993, the Portland Cement Association published a technical report entitled "Detailed
Illustration of Contingent Management Practices for Cement Kiln Dust" (Abeln et al., 1993). The
report outlined two hypothetical CKD landfill configurations. These two landfill designs are
similar to the "Modified CKD Low" and Modified CKD High" designs presented in Table 3-1.
The first CKD landfill design proposed by the cement industry focused primarily on the final cap
and disposing of a sufficient amount of CKD to prevent CKD over saturation and leakage from
the waste management unit. This design included:
• A six-inch vegetative soil layer with a permeability of 1.9 x 10"4 cm/s;
• A one-quarter inch lateral drainage layer with a permeability of 7 cm/s to remove
water that has infiltrated through the vegetative layer;
• A geofabric placed above the drainage layer to prevent fines from clogging the
drainage layer;
• A two-foot soil barrier with a permeability of 2.5 x 10"5 cm/s under the drainage
layer;
• No engineered bottom liner or leachate collection;
Draft: June 1998
3-2
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Table 3-1. Summary of Landfill Design Configurations
Design Variable
Baseline CKD
Landfill
Modified CKD Low
Modified CKD
High
Subtitle D
(composite liner;
leachate collection)
Subtitle C (double
liner: leachate
collection)
Cover Layer
Uncompacted CKD
(no cover)
0.5 ft top soil
2 ft compacted CKD
(k = 2xl0"5 cm/s)
1.0 ft top soil
0.5 ft sand drainage
layer (k =2x10"3 cm/s)
Geotextile support
fabric
2 ft compacted CKD
0.5 ft top soil
1.5 ft sand
60 mil HDPE
geomembrane
2 ft compacted soil
cap
2 ft top soil
1 ft sand
30 mil HDPE
geomembrane
2 ft compacted soil
cap
Liner Layer
Uncompacted CKD
(no liner)
4 ft compacted CKD
(k = 2xl0"5 cm/s)
Geotextile filter fabric
1 ft sand (leachate
collection layer)
Geotextile support
fabric
4 ft compacted CKD
1 ft sand (leachate
collection layer)
60 mil HDPE
geomembrane
2 ft clay
1 ft sand (leachate
collection layer)
30 mil HDPE
geomembrane
1 ft sand (leachate
detection layer)
30 mil HDPE
geomembrane
2 ft clay
Slope of Final
Cover
NA
NA
2 percent slope
2 percent slope
3 percent slope
Ground Water
Monitoring
Yes
Yes
Yes
Yes
Yes
Leachate
Collection
No leachate collection
No leachate collection
Yes
Yes (required)
Yes (required)
Source: SAIC 1997. NA means not applicable. K = hydraulic conductivity.
Draft: June 1998 3-3
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A 3:1 (3 horizontal to 1 vertical) side slope; and
• The CKD layer, with the minimum total lift according to the climatic setting, and
with three values of permeability (1 x 10"4 cm/s, 1 x 10"5 cm/s, and 1 x 10"6 cm/s).
These ranges of permeabilities were claimed to occur naturally in uncompacted
CKD at some sites and could be achieved with mild to heavy compaction at other
sites.
In the PCA report (Abeln et al., 1993), an alternative landfill design included a 4 foot-thick
compacted CKD bottom layer (permeability of 10"6 cm/s or less) and leachate collection was
proposed for sites in wet climates that could not accumulate sufficient CKD to prevent
oversaturation in the monofill. The cement industry used EPA's HELP model to calculate the
minimum thickness of CKD required to prevent over saturation of the CKD for a one-year active
life, and to determine the minimum final CKD height needed to prevent leakage through the
capped CKD management unit during a 30-year post-closure period (Abeln et al., 1993). EPA's
evaluation of these designs is summarized in Section 3.4.
3.2.2 Baseline, Subtitle D, and Subtitle C Landfill Liner Designs
A study was conducted to determine the incremental effectiveness of RCRA Subtitle D and
Subtitle C liners used in a CKD landfill over a baseline CKD landfill (uncompacted CKD in
unlined, uncovered landfill) and covers in protecting ground water resources (SAIC 1997)1. The
baseline landfill, which has minimal engineering control — no liner or leachate collection system,
was evaluated because it represents the current CKD management practice employed at many
cement plants that land dispose CKD. The Subtitle C and D designs were evaluated because they
represent EPA's default technical standard for hazardous and municipal waste landfill
respectively.
Under Subtitle D regulations, municipal solid waste landfills (MSWLFs) must comply with either
a design standard or a performance standard for landfill design. The design standard requires a
composite liner composed of two feet of soil with a hydraulic conductivity of no more than 1 x
10"7 cm/sec overlain by a flexible membrane liner (FML) and a leachate collection system. The
performance-based design must demonstrate the capability of maintaining contaminant
concentrations below the MCLs at the unit's relevant point of compliance. For the purpose of the
HELP modeling evaluation described here, the technical design standard was used.
Under Subtitle C regulations, a hazardous waste landfill must have a liner that is designed,
constructed, and installed to prevent any migration of wastes out of the landfill to the adjacent
subsurface soil or ground water or surface water at any time during the active life (including
1 SAIC, 1997, "HELP Modeling to Assess Incremental Effectiveness of Subtitle C and D Landfill Designs
Over a Baseline CKD Landfill", prepared for USEPA OSW under Contract No. 68-W4-0030, WA 215, Task 9
(January 24, 1997).
Draft: June 1998
3-4
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closure period) of the landfill. Specifically, the owner or operator must install two or more liners
and a leachate collection system above and between the liners. The lower liner must be
constructed of a least a 3-foot thick layer of recompacted clay or other natural material with a
permeability of no more than 1 x 10"7 cm/sec (see 40 CFR Part 264.301).
EPA's evaluation of the baseline, Subtitle D, and Subtitle C design configurations for CKDLF
units is summarized in Section 3.4.
3.2.3 "Modified CKD Low" and "Modified CKD High" Monofill Designs
EPA established two landfill design configurations intermediate between the baseline and the
Subtitle D default for further evaluation and possible use by cement plants in non-karst areas.
The designs were known as the "Modified CKD Low" and "Modified CKD High"2. Both
configurations use compacted CKD and cover materials in their designs.
The Modified CKD Low Design has a post-closure configuration consisting of a cover layer of
0.5 ft top soil and 2 feet of compacted CKD and a liner of 4 feet compacted CKD. No active
leachate collection system is assumed. The conditioned compacted CKD is assumed to have a
hydraulic conductivity (K) of 2 x 10"5 cm/s based on the findings summarized below.
CKD permeability data given in the Report to Congress (RTC) (EPA 1993a), Exhibit 3-16,
represent data from laboratory tests using laboratory compaction procedures. The variation in
permeability with compaction is shown in the data from the PCA (Todres, et al. 1992) and EPA
found that, for soils used in liners, differences between laboratory and field conditions may make
it unlikely that hydraulic conductivity values measured in the laboratory on remolded, pre-
construction samples are the same as the values achieved during actual liner construction (EPA,
1993b). While several alternative permeability values for CKD have been identified and proposed
since publication of the RTC, EPA conducted additional research and identified permeability data
for CKD emplaced using current compaction technologies. Data generally meeting these
requirements were found in a draft certification report to the New York State Department of
Environmental Conservation for the closure of the Independent Cement Corporation (ICC) CKD
landfill located in Greene County, New York, about 3.5 miles south of Catskill (Malcolm Pirnie,
1997). As described in the certification, approximately 70,000 cubic yards of weathered and
freshly generated CKD were placed to form a 4.5 foot-thick low permeability CKD barrier at the
ICC landfill in the period of July through October, 1996. Fifty-eight individual test results for
permeability are available showing a range of permeability (in cm/s) from 3.1 x 10"7 to 1.1 x 10"4,
with an average of 2.76 x 10"5 and a median value of 2.1 x 10"5. The PCA report on CKD
permeability achieved in the field during tests at the Ash Grove Plant in Chanute, Kansas was
consulted for comparison (Todres 1992). In these tests, various compaction equipment were
used on test strips. Twelve individual test results for permeability show a range of permeability
2
The two designs were adapted from a design proposed in a screening level economic analysis and are similar
to those identified by PCA in Abeln, et al. (1993), hence the term "modified".
Draft: June 1998
3-5
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(in cm/s) from 4.5 x 10"6 to 1.51 x 10"4, an average of 3.96 x 10"5, and a median value of 2.27 x
10"5. These results compare well with the ICC data. For the purpose of selecting the best
estimated hydraulic conductivity value for compacted CKD, a median value was selected to
reflect the special distribution of the test results as representative of how a barrier system might
perform as a whole. Based on the above analysis, a CKD permeability value of 2 x 10"5 cm/s was
selected for use in the HELP modeling of compacted CKD.3 See Section 6.2 of this background
document for additional information on the performance of CKD when used as a landfill liner.
The "Modified CKD High" Design has a post-closure configuration consisting of a cover layer of
1.0 ft top soil, a sand drainage layer of sufficient hydraulic conductivity to allow removal of water
during high rainfall events, and a geotextile fabric over compacted CKD. The liner includes an
active leachate collection layer between geotextile fabric over compacted CKD. Analysis of the
effectiveness and use of the "Modified CKD Low" and "Modified CKD High" designs is provided
in Section 3.4 of this document.
3.3 Overview of the HELP Model
The HELP model is a quasi-two dimensional hydrologic model of water movement across, into,
through and out of landfills. The model accepts weather, soil, and landfill design data, and uses
solution techniques that account for the effects of surface storage, snow melt, runoff, infiltration
into the subsurface, evapotranspiration, vegetative growth, soil moisture storage, lateral
subsurface drainage, leachate recirculation, unsaturated vertical drainage, and leakage through
soil, geomembrane, or composite liners. Landfill systems including various combinations of
vegetation, cover soils, waste cells, lateral drainage layers, low permeability barrier soils, and
synthetic geomembrane liners may be modeled. The model was developed to conduct water
balance analysis of landfills, cover systems, and solid waste disposal and containment facilities.
As such, the model facilitates rapid estimation of the amounts of runoff, evapotranspiration,
drainage, leachate collection, and liner leakage that may be expected to result from the operation
of a wide variety of landfill designs. The primary purpose of the model is to assist in the
comparison of design alternatives as judged by their water balances. The model is applicable to
open, partially closed, and fully closed sites (Schroeder, et. al., 1994).
HELP is a water-balance model that can predict leakage from a landfill system, but cannot address
chemical transformations or transport processes that control the contaminant concentrations at
regulatory points of compliance (POCs). As noted in Section 3.1, however, for CKD landfills
located in karst terrains, EPA is using the landfill liner leakage rate to estimate the protectiveness
offered by the liner design. The model has additional limitations with respect to the arrangement
of layers modeled (e.g. a barrier soil layer cannot overlie a lateral drainage layer). However, the
landfill designs modeled for the evaluation of CKD landfill designs did not have any of these
The permeability estimates described here are based on data from the compaction of fresh or weathered
CKD. However, the Agency is proposing that prior to compaction, CKD should be moisture-conditioned to improve
control of fugitive dust emissions and facilitate bonding of particles to reduce leaching of contaminants from the CKD.
Draft: June 1998
3-6
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limitations. Certain layer configurations can result in the model predicting very high water
accumulation on top of a cover or liner layer, and this results in unexpected predictions for
infiltration, but, again, the landfill design configurations modeled in this analysis did not produce
this type of result.
One further limitation of this type of modeling lies in the fact that the model inputs (such as
landfill area, percent of area from which runoff can occur, SCS curve number, waste layer
properties, etc.) represent estimates of national values, not facility-specific values. The EPA is
performing this analysis to determine a default landfill design configuration that will be protective
in most CKD landfill locations. The leakage rates predicted in this analysis do not represent
precise values that can be expected from any one CKD landfill using these designs, but are instead
order-of-magnitude estimates of potential leakage from the various designs.
3.4 CKD Landfill Modeling Results
EPA conducted a series of technical analyses to evaluate the various landfill design configurations
against proposed performance standards. Because cement manufacturing facilities are located in a
wide range of climatic and hydrogeologic settings, it was recognized that a "one-size-fits-all"
approach to a developing a technical standard was not appropriate: facilities should be able to
develop landfill designs tailored to site-specific climatic and hydrogeologic conditions to achieve
the performance standard.
Using the Hydrologic Evaluation of Landfill Performance (HELP) model, EPA estimated landfill
leakage rates for the various landfill design configurations summarized in Table 3-1. Each
configuration was modeled for a range of climate and rainfall conditions adequate to capture the
range of climate conditions and rainfall amounts at cement manufacturing plants in the U.S. and
Puerto Rico. Using the HELP model, post-closure leakage rates were predicted for a baseline
landfill configuration and for the same size landfill using the "Modified CKD Low", "Modified
CKD High", Subtitle D, and Subtitle C designs. The modeling results provide a basis for
comparing the performance of the various landfill designs (though it is recognized that site-
specific landfill designs should be determined after considering site-specific information regarding
climate, site hydrogeology, and waste characteristics).
The Subtitle D and Subtitle C designs were modeled using covers with both uncompacted and
compacted CKD. Each landfill configuration was modeled using climate conditions from eight
locations representing ranges of precipitation (5.81 to 65.33 inches/year) and warm and cold
climates for both the operating life and post-closure care period of the landfill. The modeling
results for the eight locations are summarized in Table 3-2.
Results for the baseline design showed average post-closure leakage rates between 0.95 and 29.7
in/yr (depending on climate). The average post-closure leakage rates from the "Modified CKD
Low" design ranged from 0.011 to 14.9 inches/year and the "Modified CKD High" design ranged
from 0.013 to 16.8 inches/year. Results for both Subtitle D and Subtitle C liner and cover
Draft: June 1998
3-7
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configurations showed leakage rates predicted by the model to be on the order of 10"6 in/yr,
essentially indistinguishable from zero. This result indicates that the Subtitle D design is as
effective as the Subtitle C design for reducing leakage from CKD landfills.
EPA then assembled a database of facility-specific information on CKD generation rates, CKD
management and disposal practices, hydrogeologic information, and climate to conduct facility-
specific design demonstrations. After consideration of the damage cases, the increased risk posed
by locating CKD landfills in karst, the post-closure leakage rates estimated for the various landfill
configurations, and the limitations of ground water transport models for use in karst
hydrogeologic settings, EPA determined that the Subtitle D default technical design standard
would be appropriate for CKD landfills located in karst environments. EPA then conducted
additional modeling, using the Multimedia Exposure Assessment Model (MULTIMED), to
estimate which landfill designs would be appropriate for CKDLF units located in non-karst areas.
The results of the MULTIMED analysis are discussed in Chapter 4.
3.5 Conclusions
Based on these results, EPA concluded that the Subtitle D default design would be adequate to
control releases to ground water for all CKDLF units including those in karst areas. By
minimizing net infiltration by means of a Subtitle D default landfill design, there will be a
corresponding low potential for ground water contamination. Note that in areas of unstable
ground (such as landslides, sinkholes, poor foundation conditions, etc.), Subtitle D regulations
require a demonstration that suitable engineering measures have been incorporated in the landfill
design to ensure that the structural components of the landfill will not be disrupted (40 CFR
258.15). Similar requirements are proposed for CKDLF units located in karst hydrogeologic
settings. EPA's proposed location restrictions for CKDLF units at karstic and non-karstic sites
are further discussed in Chapter 5 of this background document.
Draft: June 1998
3-8
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Table 3-2. HELP Model Results
Result
Baseline
Modified
CKD Low
Modified
CKD
High
Subtitle D
uncompacted
CKD
Subtitle D
compacted
CKD
Subtitle C
uncompacted
CKD
Subtitle C
compacted
CKD
Fresno, California
Peak leakage, post closure (in/yr)
2.8
0.09
0.055
0.000001
0.000001
0.000003
0.000003
Average leakage, post closure (in/yr)
1.2
0.018
0.016
0
See note
0
0
0
Miami, Florida
Peak leakage, post closure (in/yr)
18.5
17.0
0.18
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr)
8.5
3.6
0.049
0
0
0
0
Boise, Idaho
Peak leakage, post closure (in/yr)
1.1
0.069
0.048
0.000002
0.000002
0.000002
0.000002
Average leakage, post closure (in/yr)
0.95
0.011
0.013
0
0
0
0
Duluth, Minnesota
Peak leakage, post closure (in/yr)
4.4
0.24
0.046
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr)
1.4
0.056
0.015
0
0
0
0
Draft: June 1998
3-9
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Table 3-2. HELP Model Results
Modified
Modified
Subtitle D
Subtitle D
Subtitle C
Subtitle C
Result
Baseline
CKD Low
CKD
uncompacted
compacted
uncompacted
compacted
High
CKD
CKD
CKD
CKD
Raleigh, North Carolina
Peak leakage, post closure (in/yr)
18.6
17.2
0.42
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr)
5.97
2.2
0.047
0
0
0
0
Mt. Washington, New Hampshire
Peak leakage, post closure (in/yr)
49.0
34.8
36.6
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr)
29.7
14.9
16.8
0
0
0
0
Oklahoma City, Oklahoma
Peak leakage, post closure (in/yr)
5.68
0.51
0.073
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr)
1.67
0.063
0.018
0
0
0
0
Salem, Oregon
Peak leakage, post closure (in/yr)
31.7
29.5
27.4
0.000003
0.000003
0.000003
0.000003
Average leakage, post closure (in/yr) 17.4
11.9
9.3
0
0
0
Note: The HELP model reports average leakage rates to 5 decimal places, and reports peak leakage rates to 6 decimal places,
therefore average leakage rates may indicate zero even when peak leakage rates are greater than zero.
Draft: June 1998
3-10
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References
Abeln, D.L., R.J. Hastings, R.J. Schreiber, and C. Yonley 1993. Detailed Illustration of
Contingent Management Practices for Cement Kiln Dust. Schreiber, Grana & Yonley,
Inc., St. Louis, MO. Prepared for the Portland Cement Association., Skokie, IL.
Research and Development Bulletin SP115T.
ICF Consulting Group (ICF), 1995. Memo to B. Schoenborn (USEPA) from K. Cornils, E.
Ijjasz, B. Vanatta and P. Soyka (ICF Incorporated), entitled "Potential Impacts on Ground
Water of the Cement Industry's Proposed CKD Management Plan". July 14, 1995. (EPA
Contract No. 68-W4-0030, Work Assignment 9).
Malcolm Pirnie, 1997. Certification Report, Independent Cement Corporation, Catskill, New
York. Malcolm Pirnie, Inc. Albany, New York. February 1997 DRAFT.
Schroeder, P.R., C.M. Lloyd, P. A. Zappi, and N.M. Aziz, 1994, The Hydrologic Evaluation of
Landfill Performance (HELP) Model, User's Guide for Version 3, EPA/600/R-94/168a,
Risk Reduction Engineering Laboratory, Office of Research and Development, U.S.
Environmental Protection Agency, Cincinnati, Ohio, September, 1994.
Science Applications International Corporation (SAIC), 1997. HELP Modeling to Assess the
Incremental Effectiveness of Subtitle C and D Landfill Designs Over a Baseline CKD
Landfill. Submitted to USEPA Office of Solid Waste. January 24, 1997. (EPA Contract
No. 68-W4-0030, Work Assignment 215, Task 9).
Todres, H.A., 1992, Cement Kiln Dust: Field Compaction and Resulting Permeability. Research
and Development Bulletin RD106T. Portland Cement Association, Skokie Illinois.
Todres, H., Mishulovich A. and Ahmed, J., 1992. CKD Management: Permeability. Research
and Development Bulletin RD103T. Portland Cement Association, Skokie, 111.
USEPA, 1993a, Report to Congress on Cement Kiln Dust Volume II Methods and Findings,
Office of Solid Waste (December).
USEPA, 1993b, Solid Waste Disposal Facility Criteria, 40 CFR Part 258, Technical Manual.
US EPA, November 1993.
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Chapter 4: Agency Analysis of Ground Water Controls Required at Cement
Manufacturing Facilities
This chapter describes an analysis conducted by EPA to predict the ground water controls, if any,
that likely would be employed at each cement plant in the U.S. and Puerto Rico to comply with
the proposed ground water protection standards. To conduct this analysis, a four-step process
was developed: (1) development of a decision framework, (2) identification and collection of the
data required to apply the decision framework, (3) identification of landfill design configurations
capable of meeting the performance standard in karst and non-karst areas, and (4) application of
the decision framework using information from EPA's cement plant database.
The decision framework was developed so that a landfill design configuration could be assigned
to each cement manufacturing facility in the U.S. and Puerto Rico. The decision framework was
then applied to each of the 110 cement plants in the Agency's cement plant database to predict the
minimum ground water protection measures required to achieve the proposed performance
standard for new and actively managed CKDLF units.
4.1 Development of the Decision Framework
The decision framework, presented in Figure 4-1, was designed to establish a rationale for
predicting the type of ground water controls required at each cement plant. Accordingly, each
"end point" of the decision tree had to represent a waste management scenario or landfill design
that could be employed at cement plants, after consideration of facility-specific information. The
end points (sometimes referred to as "terminal nodes" in a decision tree) are:
• No ground water controls (e.g., at facilities that beneficially reuse all net CKD);
• Baseline landfill with minimal engineering design (e.g. no liner or leachate
collection system);
• "Modified CKD Low" landfill design (see Table 3-1 in Chapter 3 of this
background document);
• "Modified CKD High" landfill design (see Table 3-1 in Chapter 3 of this
background document);
• Subtitle D default design for CKD landfills in karst areas; and
• On-site land disposal prohibited (e.g., caves or sinkholes present) or an alternative
design is required.
Draft: June 1998
4-1
-------
Negligible risk of release to ground
water. No ground water controls
required.
Does facility land
dispose its CKD
on-site?
Apply HELP and MULTIMED
models to determine an
acceptable site-specific landfill
design
See Figure 4-2
Is the facility located in karst or
underlain by highly permeable or
fractured aquifers?
Alternate landfill design
required or On-site land-
disposal of CKD prohibited
Will a default Subtitle D design
be adequate to achieve the performance
standard?
Yes
Subtitle D default design
(leakage rate = 0)
* Answer "yes" for cement plants located in karst or highly permeable aquifers (subject to non-Darcy flow).
Answer "no" for cement plants located in mature karst areas with evidence of subsidence, such as sinkholes.
Figure 4-1: Decision Framework
Draft: June 1998
4-2
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The decision framework consists of a series of questions (represented by "nodes" on a flow
chart). Each question relates to a key landfill management standard in the proposed rule related
to the landfill design criteria or karst areas. The first question, "Does the facility generate net
CKD?" is intended to breakout the population of cement plants into two categories: those
potentially subject to the CKD management standards, and those not subject to the standards.
Because some facilities transport all of their CKD off site for beneficial use, the question "Does
the facility land dispose its CKD on site?" is included to remove those facilities from further
evaluation in the decision framework.
To determine the landfill design configuration required, first it is necessary to determine whether
the proposed site is in a karst hydrogeologic setting. If the site is in karst, the owner would need
to construct a landfill based on the Subtitle D default design (i.e., composite liner with leachate
collection) and demonstrate that engineering measures have been incorporated in the CKDLF
unit's design to ensure that the integrity of the structural components will not be disrupted.
Otherwise, an alternative design would be required or on-site disposal would be prohibited. For
the purpose of this analysis, it was assumed that such a demonstration could be made for all karst
sites except those with historical evidence of subsidence. All karst sites not subject to subsidence
are assigned a "Subtitle D" configuration. If the site is NOT in karst, then a performance-based
design demonstration is made using a leachate source model and a ground water transport model
(see Section 4.3). For this analysis, two key assumptions are made: (1) the decision framework
assumes CKD will no longer be disposed in quarries and that land is available at each facility for a
new landfill (or lateral expansion of an existing operating unit) and (2) landfill location and
operation will not be restricted by the presence of a shallow water table, flood plains, wetlands,
fault areas, or seismic impact zones.
4.2 Data Requirements and Data Collection
Application of the decision framework required facility-specific data such as CKD net generation
rates, description of the hydrogeologic setting (i.e., karst or non-karst), the potential for
subsidence, facility location, and climate data. All data elements were not required for every
cement plant because some cement plants could be categorized quickly with minimal information.
For example, facilities that do not land-dispose CKD will not require ground water controls.
The data were drawn from various sources including the following: the 1994 NOD A Risk
Assessment, Section 2 Ground Water Contamination and Drinking Water Risks from Cement Kiln
Dust Managed Over Karst Aquifers (USEPA, 1994); 1990 PC A and 1995 APCA survey results
(APCA 1995); and U.S. Geological Survey (USGS) maps and other references documented and
summarized in Chapter 2 of this background document (see Chapter 2, Tables 2-3 and 2-4).
Draft: June 1998
4-3
-------
4.3 Application of the Decision Framework to the Cement Plant Database
The decision framework (Figure 4-1) enabled the Agency to predict the appropriate landfill design
configuration for each of the 110 cement plants in the database. Using facility-specific
information, which is summarized in Table 4-1, each cement plant was assigned a waste
management scenario or landfill design (e.g., no ground water controls required, baseline landfill,
modified CKD low, modified CKD high, Subtitle D default, or alternate design). The results of
applying the decision framework to each cement plant also are presented in Table 4-1.
The decision framework was applied as follows: Facilities listed in the database with zero CKD
wasted in 1995 were assigned to the category "No Ground Water Controls Required". Thirty-six
out of 110 cement plants fall into this category.
Next, the remaining 74 facilities that waste net CKD were reviewed to determine which ones are
located in karst. Fifty-six of the 74 facilities are located in karst settings, and the remaining 18 are
located in non-karst settings. The karst underlying these 56 facilities was further categorized
based on the maturity of the karst, and the corresponding risk of landfill failure due to sinkholes as
evidenced by the presence of sinkholes or other indicators of historical subsidence. Five (5)
facilities located in karst with evidence of subsidence were placed in the category "Alternate
Design Required or On-Site Land Disposal Prohibited". The remaining 51 "karst" sites were
assigned a "Subtitle D" default design.
Finally, the remaining eighteen (18) facilities that are not located in karst, but do waste net CKD,
were assigned a performance-based landfill design after taking into consideration site-specific
factors such as site hydrogeology and climate. EPA used the HELP model (described in Chapter
3), coupled with the Multimedia Exposure Assessment Model (MULTIMED) (Sharp-Hansen, S.,
et al, 1990), to estimate the appropriate landfill design required to meet the performance standard
at each cement plant located in a non-karst setting. The modeling approach is outlined in Figure
4-2 and described in detail in the following sections.
Draft: June 1998
4-4
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Table 4-1. Site Characteristics and Quantity of Net, Beneficially Used, and Wasted CKD, U.S. Cement Manufacturing
Facilities
Facility Name
City
State
Does Facility Generate Is Some Or All CKD
Net CKD? (see Note 1) Used For Beneficial
Purposes? (see Note 1)
Is Net CKD Wasted?
(see Note 1)
Potential for Karst
Hydrogeologic Setting
(from Table 2-3)
Potential for
Subsidence (e.g.,
mature karst with
evidence of sinkholes)
(see Table 2-3)
Ground Water
Controls Required
Based on Decision
Framework
Alamo Cement Co.
San Antonio
(Cementville)
TX
No
No
No
Yes
No
None (No Net CKD)
Allentown Cement Co. Inc.
Blandon
PA
No
No
No
Yes
No
None (No Net CKD)
Armstrong Cement &
Supply Corp.
Cabot
PA
Yes
Yes
No
Yes
No
None (No Waste CKE
Ash Grove Cement Co.
Chanute
KS
Yes
No
Yes
No
No
Modified CKD High
Ash Grove Cement Co.
Durkee
OR
No
No
No
No
No
None (No Net CKD)
Ash Grove Cement Co.
Foreman
AR
Yes
No
Yes
Yes
No
Subtitle D
Ash Grove Cement Co.
Inkom
ID
Yes
No
Yes
Yes
No
Subtitle D
Ash Grove Cement Co.
Louisville
NE
Yes
No
Yes
No
No
Modified CKD Low
Ash Grove Cement Co.
Montana City
MT
Yes
No
Yes
Yes
No
Subtitle D
Ash Grove Cement Co.
Nephi
UT
No
No
No
Yes
No
None (No Net CKD)
Ash Grove Cement Co.
Seattle
WA
No
No
No
No
No
None (No Net CKD)
Blue Circle Inc.
Atlanta
GA
No
No
No
No
No
None (No Net CKD)
Blue Circle Inc.
Calera
AL
Yes
Yes
Yes
Yes
No
Subtitle D
Blue Circle Inc.
Harleyville
SC
No
No
No
Yes
No
None (No Net CKD)
Blue Circle Inc.
Ravena
NY
Yes
Yes
Yes
Yes
No
Subtitle D
Blue Circle Inc.
Tulsa
OK
Yes
Yes
Yes
Yes
No
Subtitle D
Calaveras Cement Co
Redding
CA
No
No
No
No
No
None (No Net CKD)
Calaveras Cement Co.
Tehachapi
CA
No
No
No
No
No
None (No Net CKD)
Calif. Portland Cement
Colton
CA
Yes
Yes
Yes
No
No
Modified CKD Low
Calif. Portland Cement
Mojave
CA
No
No
No
No
No
None (No Net CKD)
Calif. Portland Cement
Rillito
AZ
No
No
No
No
No
None (No Net CKD)
Capitol Aggregates, Inc.
San Antonio
TX
Yes
No
Yes
Yes
No
Subtitle D
Capitol Cement Corporation
Martinsburg
wv
Yes
Yes
Yes
Yes
No
Subtitle D
Centex
Fernley
NV
No
No
No
No
No
None (No Net CKD)
Centex
Laramie
WY
No
No
No
Yes
No
None (No Net CKD)
Draft: June 1998
4-5
-------
Facility Name City
Centex La Salle
Continental Cement Co., Hannibal
Inc.
Dacotah Cement Rapid City
Dixon-Marquette Dixon
State Does Facility Generate Is Some Or All CKD Is Net CKD Wasted? Potential for Karst Potential for Groundwater
Net CKD? (see Note 1) Used For Beneficial (see Note 1) Hydrogeologic Setting Subsidence (e.g., Controls Required
Purposes? (see Note 1) (from Table 2-3) mature karst with Based on Decision
evidence of sinkholes) Framework
(see Table 2-3)
Dragon Products Co.
IL
MO
SD
IL
Thomaston ME
ESSROC Materials Bessemer
ESSROC Materials Frederick
ESSROC Materials Logansport
ESSROC Materials Nazareth
ESSROC Materials (Lone Nazareth
Star)
ESSROC Materials Speed
Florida Crushed Stone Brooksville
Giant Cement Holding, Inc. Harleyville
Giant Cement Holding Bath
(Keystone)
Glens Falls Cement CO.,
Inc.
Holnam Inc. Ada
Holnam Inc. Artesia
Holnam Inc. Clarksville
Holnam Inc. Dundee
Holnam Inc. Florence
Holnam Inc. Fort Collins
Holnam Inc. Holly Hill
Holnam Inc. Mason City
Holnam Inc. Midlothian
PA
MD
IN
PA
PA
IN
FL
SC
PA
Glens Falls NY
OK
MS
MO
MI
CO
CO
SC
IA
TX
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
No
No
Yes
Yes
No
Yes
No
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No None (No Net CKD)
No Subtitle D
No Subtitle D
Yes Alternative Design
Required
No Subtitle D (based on
HELP/MULTIMED
Modeling)
No Subtitle D
No Subtitle D
No Subtitle D
Yes None (No Net CKD)
Yes Alternative Design
Required
No Subtitle D
Yes None (No Waste CKD)
No Subtitle D
No Subtitle D
No Subtitle D
No Modified CKD High
No Subtitle D
No Subtitle D
No None (No Waste CKD)
No Subtitle D
No Subtitle D
No Subtitle D
No None (No Net CKD)
No None (No Waste CKD)
Draft: June 1998
4-6
-------
Facility Name
City
State
Does Facility Generate Is Some Or All CKD
Net CKD? (see Note 1) Used For Beneficial
Purposes? (see Note 1)
Is Net CKD Wasted?
(see Note 1)
Potential for Karst
Hydrogeologic Setting
(from Table 2-3)
Potential for
Subsidence (e.g.,
mature karst with
evidence of sinkholes)
(see Table 2-3)
Ground Water
Controls Required
Based on Decision
Framework
Holnam Inc.
Morgan
UT
Yes
Yes
No
Yes
No
None (No Waste CKD)
Holnam Inc.
Seattle
WA
Yes
Yes
No
No
No
None (No Waste CKD)
Holnam Inc.
Theodore
AL
No
No
No
Yes
No
None (No Net CKD)
Holnam Inc.
Three Forks
MT
Yes
Yes
Yes
Yes
No
Subtitle D
Independent Cement Corp.
Catskill
NY
Yes
Yes
Yes
Yes
No
Subtitle D
Independent Cement Corp.
Hagerstown
MD
Yes
Yes
Yes
Yes
No
Subtitle D
Kaiser Cement Corp.
Permanente
CA
No
No
No
No
No
None (No Net CKD)
Kosmos Cement Co.
Kosmosdale
KY
Yes
Yes
No
Yes
No
None (No Waste CKD)
Kosmos Cement Co.
Pittsburgh
PA
Yes
Yes
No
No
No
None (No Waste CKD)
Lafarge Corporation
Alpena
MI
Yes
No
Yes
No
No
Modified CKD Low
Lafarge Corporation
Buffalo
IA
Yes
Yes
Yes
Yes
No
Subtitle D
Lafarge Corporation
Fredonia
KS
Yes
No
Yes
No
No
Modified CKD High
Lafarge Corporation
Grand Chain
IL
Yes
No
Yes
Yes
No
Subtitle D
Lafarge Corporation
Paulding
OH
Yes
No
Yes
Yes
No
Subtitle D
Lafarge Corporation
Sugar Creek
MO
Yes
Yes
Yes
Yes
No
Subtitle D
Lafarge Corporation
Whitehall
PA
No
No
No
Yes
Yes
None (No Net CKD)
Lehigh Portland Cement
Leeds
AL
No
No
No
Yes
Yes
None (No Net CKD)
Lehigh Portland Cement
Mason City
IA
Yes
Yes
Yes
Yes
No
Subtitle D
Lehigh Portland Cement
Mitchell
IN
Yes
Yes
Yes
Yes
No
Subtitle D
Lehigh Portland Cement
LTnion Bridge
MD
Yes
Yes
Yes
Yes
No
Subtitle D
Lehigh Portland Cement
Waco
TX
Yes
No
Yes
Yes
No
Subtitle D
Lehigh Portland Cement
York
PA
Yes
Yes
No
Yes
No
None (No Waste CKD)
Lone Star Industries
Cape
Girardeau
MO
Yes
No
Yes
Yes
Yes
Alternative Design
Required
Lone Star Industries
Greencastle
IN
Yes
No
Yes
Yes
No
Subtitle D
Lone Star Industries
Oglesby
IL
Yes
No
Yes
No
No
Subtitle D (based on
HELP/MULTIMED
Modeling)
Lone Star Industries
Pryor
OK
Yes
Yes
Yes
Yes
No
Subtitle D
Draft: June 1998
4-7
-------
Facility Name
City
State
Does Facility Generate
Net CKD? (see Note 1)
Is Some Or All CKD
Used For Beneficial
Purposes? (see Note 1)
Is Net CKD Wasted?
(see Note 1)
Potential for Karst
Hydrogeologic Setting
(from Table 2-3)
Potential for
Subsidence (e.g.,
mature karst with
evidence of sinkholes)
(see Table 2-3)
Ground Water
Controls Required
Based on Decision
Framework
Lone Star Industries
Sweetwater
TX
No
No
No
Yes
No
None (No Net CKD)
Medusa Cement Co.
Charlevoix
MI
Yes
Yes
Yes
Yes
No
Subtitle D
Medusa Cement Co.
Clinchfield
GA
No
No
No
Yes
No
None (No Net CKD)
Medusa Cement Co.
Demopolis
AL
Yes
Yes
Yes
Yes
No
Subtitle D
Medusa Cement Co.
Wampum
PA
Yes
Yes
No
Yes
No
None (No Waste CKD)
Mitsubishi Cement Corp.
Lucerne
Valley
CA
Yes
No
Yes
No
No
Modified CKD Low
Monarch Cement Co.
Humboldt
KS
Yes
No
Yes
No
No
Modified CKD High
National Cement Co. Of
Alabama
Ragland
AL
No
No
No
Yes
No
None (No Net CKD)
National Cement Co. Of
California
Lebec
CA
Yes
No
Yes
No
No
Modified CKD Low
North Texas Cement
Midlothian
TX
Yes
Yes
Yes
Yes
No
Subtitle D
Pennsuco Cement Co.
(Tarmac)
Medley
FL
Yes
No
Yes
Yes
No
Subtitle D
Phoenix Cement Co.
Clarkdale
AZ
Yes
Yes
No
Yes
No
None (No Waste CKD)
Puerto Rico Cement Co.
Ponce
PR
Yes
Yes
Yes
No
No
Modified CKD High
RC Cement Co. Inc.
(Heartland Cement Co.)
Independence
KS
Yes
Yes
Yes
Yes
No
Subtitle D
RC Cement Co. Inc.
(Hercules Cement Co.)
Stockertown
PA
Yes
No
Yes
Yes
Yes
Alternative Design
Required
RC Cement Co. Inc. (River
Cement Co.)
Festus
MO
Yes
No
Yes
Yes
No
Subtitle D
RC Cement Co. Inc. (Signal
Mountain Cement Co.)
Chattanooga
TN
Yes
Yes
Yes
Yes
No
Subtitle D
Rinker Portland Cement
Corp.
Miami
FL
Yes
No
Yes
Yes
No
Subtitle D
Rio Grande Cement Co.
(Holnam Inc.)
Tijeras
NM
Yes
No
Yes
Yes
No
Subtitle D
Riverside Cement Co.
Oro Grande
CA
Yes
Yes
Yes
No
No
Modified CKD Low
Riverside Cement Co.
Riverside
CA
Yes
No
Yes
No
No
Modified CKD Low
RMC Lonestar - Santa Cruz
Davenport
CA
Yes
Yes
Yes
No
No
Modified CKD Low
Draft: June 1998
4-8
-------
Facility Name
City
State
Does Facility Generate
Net CKD? (see Note 1)
Is Some Or All CKD
Used For Beneficial
Purposes? (see Note 1)
Is Net CKD Wasted?
(see Note 1)
Potential for Karst
Hydrogeologic Setting
(from Table 2-3)
Potential for
Subsidence (e.g.,
mature karst with
evidence of sinkholes)
(see Table 2-3)
Ground Water
Controls Required
Based on Decision
Framework
Roanoke Cement Co.
Cloverdale
VA
Yes
Yes
Yes
Yes
No
Subtitle D
Royal Cement Co., Inc.
Logandale
NV
Yes
No
Yes
No
No
Modified CKD Low
San Juan Cement Co.
Dorado
PR
Yes
No
Yes
No
No
Modified CKD High
Southdown
Brooksville
FL
Yes
No
Yes
Yes
Yes
Alternative Design
Required
Southdown
Fairbom
OH
Yes
Yes
No
Yes
No
None (No Waste CKD)
Southdown
Knoxville
TN
Yes
Yes
Yes
Yes
No
Subtitle D
Southdown
Lyons
CO
Yes
Yes
Yes
Yes
No
Subtitle D
Southdown
Odessa
TX
Yes
Yes
Yes
Yes
No
Subtitle D
Southdown
Victorville
CA
Yes
No
Yes
No
No
Modified CKD Low
Sunbelt Cement Corp.
(Lafarge Corporation)
New
Braunfels
TX
Yes
No
Yes
Yes
No
Subtitle D
Texas Industries
Midlothian
TX
Yes
No
Yes
Yes
No
Subtitle D
Texas Industries (TXI
Cement)
New
Braunfels
TX
Yes
Yes
Yes
Yes
No
Subtitle D
Texas-Lehigh Cement Co. Buda
TX
No
No
No
Yes
No
None (No Net CKD)
Notes to Table:
1. Annual CKD generation, disposal, and reuse rates are business confidential and are not shown. Net, beneficially used, and wasted CKD quantities for reporting
plants are 1995 quantities from the 1995 CKD Survey (PCA 1995). Quantities from the 1991 CKD Survey were assumed for non-reporting plants. Two
plants did not report quantities in either survey (Riverside Cement, Riverside, CA and San Juan Cement, PR). Quantities for these two plants are based on
average net CKD to clinker production ratios by kiln type, which were calculated from reporting plants.
Draft: June 1998
4-9
-------
Collect site-specific hydrogeological
data or make estimates where
data not available.
I
Select contaminant to be simulated
and determine leachate
concentration.
I
Select one of three CKD landfill designs
(a) Baseline
(b) Modified CKD Low
(c) Modified CKD High
Run HELP/MULTIMED
Calculate DAF
Does DAF indicate
MCL will not be
exceeded at POC?
Acceptable design
* If none of the three CKD landfill designs are acceptable, then a
"Subtitle D" design is selected by default.
Figure 4-2: Procedure for Using MULTIMED to Select Performance-Based Landfill
Designs for CKDLF Units Located in Non-Karst Settings
Draft: June 1998
4-10
-------
4.3.1 Overview of MULTIMED Modeling Approach
The MULTIMED model simulates the transport and transformation of contaminants released
from a waste disposal facility into the multimedia environment. Releases to either air or soil,
including the unsaturated and the saturated zones, and possible interception of the subsurface
contaminant plume by a surface stream are included in the model. Thus, the model can be used as
a technical and quantitative management tool to address the problem of the land disposal of
chemicals in the multimedia environment. MULTIMED uses analytical and semi-analytical
solution techniques to solve the mathematical equations describing flow and transport. The
simplifying assumptions required to obtain the analytical solutions limit the complexity of the
systems that can be represented by MULTIMED.1 The model does not account for site-specific
spatial variability, the shape of the land disposal facility, site-specific boundary conditions, or
multiple aquifers and pumping wells. Nor can MULTIMED simulate processes, such as flow in
fractures and chemical reactions between contaminants, which can have a significant effect on the
concentration of contaminants at a site.
MULTIMED can, however, be used as a screening-level model that allows users to obtain an
understanding of a transport system, and to make comparisons between transport systems (Sharp-
Hansen, et. al., 1990).
As can be seen in the above model descriptions, neither HELP nor MULTIMED alone is
sufficient for assessing the potential environmental impacts of releases from CKD landfills. As
described is Chapter 3, HELP is a water-balance model that can predict leakage from a landfill
system, but cannot address chemical transformations or transport processes that control the
contaminant concentrations at regulatory points of compliance (POCs). While MULTIMED can
predict constituent concentrations based on attenuation and dilution processes, it does not
account for specific landfill properties that control the initial leakage of contaminants into the
subsurface. Therefore, as a rule, HELP and MULTIMED (or another equivalent subsurface
transport model) are used together to estimate the potential for ground-water contamination from
land disposal facilities. This is the methodology adopted in the current analysis of prospective
CKD landfill designs. A schematic representation of the coupling of the HELP and MULTIMED
1 For the MULTIMED modeling described here, several simplifying assumptions were made, including:
steady-state leachate generation (no source term decay); the receptor well is located downgradient of the facility and
intercepts the contaminant plume; homogeneous porous aquifer; uniform flow in aquifer; and contaminant concentration
is calculated at the top of the aquifer, which will likely result in a "worst-case scenario" evaluation.
Draft: June 1998 4-11
-------
models is provided in Figure 4-3.
The approach used in this section to evaluate CKD landfill design requirements follows that
recommended by EPA for identifying landfill design requirements under RCRA Subtitle D as
described in the "Solid Waste Disposal Facility Criteria, 40 CFR 258, Technical Manual"
(USEPA, 1993b). Use of a fate and transport models such as MULTIMED in conjunction with a
leachate source model such as HELP can be used for designing solid waste landfills to meet the
Subtitle D performance standard. EPA's procedure for using HELP/MULTIMED to design solid
waste landfills is summarized in Figure 4-2 and in the following bullets:
• "Collect, site-specific hydrogeologic data, including amount of leachate generated;
• Identify the contaminant(s) to be simulated and the POC;
• Propose a landfill design and determine the corresponding infiltration rate [using the
HELP model];
• Run MULTIMED and calculate the dilution attenuation factor (DAF) (i.e., the factor by
which the concentration is expected to decrease between the landfill unit and the POC);
and
• Multiply the initial contaminant concentration by the DAF and compare the resulting
concentrations to the MCLs to determine if the design will meet the [performance]
standard" (USEPA, 1993b).
Precipitation
Monitoring Well
at POC
Figure 4-3: Schematic Representation of Coupling the
III I P Model and the MULTIMED Model.
HELP
model
MULTIMED
model
Infiltration through and
leakage from the landfill
I Transport through the unsaturated and
I saturated subsurface materials
Draft: June 1998
4-12
-------
As a first step in this evaluation of CKD landfill designs, EPA used the HELP model to estimate
leakage rates from a range of landfill designs, as described in Chapter 3. EPA then calculated the
impact of this leakage at the hypothetical POCs using a fate and transport model (i.e.,
MULTIMED). For the landfill designs summarized in Chapter 3, Table 3-1, the MULTIMED
model was run in the most conservative mode for this analysis and included a non-karstic
limestone setting and no attenuation processes (e.g., no adsorption, no precipitation, and no
mineralization of contaminants). The use of a contaminant adsorption term may be appropriate at
individual sites, if supported by site-specific data. Comparing the DAFs resulting from the various
modeled landfill designs provide an indication of the relative performance of the landfill design
(i.e., higher DAFs correspond to better performing landfill designs).
As indicated in Chapter 2, at least nine out of the thirteen ground water damage cases for CKD
disposal sites are associated with karst conditions where conduit ground water flow is prevalent.
Ground water flow and risk assessments for these areas are difficult to model because of the
distribution of the open subsurface fractures and conduits will vary greatly within a particular site
as well as from site to site and can not be modeled using MULTIMED. Therefore, landfill
performance in karstic areas could not be evaluated using the same approach as for landfills in
non-karstic areas.
4.3.2 MULTIMED Modeling to Establish Designs for CKD Landfills in Non-Karst
Environments
MULTIMED modeling (combined with the HELP modeling results) was conducted to establish
an appropriate design for CKD landfills so that the decision framework could be applied to
CKDLF units that will not be located in karst areas. Specifically, the MULTIMED model was
used to predict DAFs for various combinations of infiltration rates and rainfall rates taken from
the HELP modeling analysis. These DAFs were then applied to the known composition of CKD
leachate to determine whether concentrations of constituents of concern will be below their
regulatory MCLs at the POC.
For this analysis, two POCs were considered. First, the MULTIMED model was used to predict
DAFs at a POC 500 feet (152 meters) immediately hydraulically downgradient of the landfill
boundary (i.e., zero degrees off the plume center line). Second, the model was used to predict the
dilution factor 3 feet (approximately 1 meter) from the unit boundary, which is the minimum
distance permissible in the MULTIMED model. This distance also is consistent with the POC
used under Subtitle C for hazardous waste landfills.
Table 4-2 lists the required inputs to the MULTIMED model and the values selected for this
analysis. Because few of the required site-specific hydrogeologic data were available for all
cement plants, it was necessary to make reasonable estimates for many of the model input
parameters.
Draft: June 1998
4-13
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4.3.3 MULTIMED Results
This Section presents the MULTIMED model results for various combinations of leakage rates
and climate settings for the Baseline, Modified CKD Low, and Modified CKD High landfill
designs.2 The precipitation and leakage rates predicted by the HELP model for these designs
were reviewed and it was determined that they could be grouped together such that each landfill
configuration can be assigned an approximate leakage rate (predicted by the HELP model) of
0.01 inches per year (in/yr), 0.05 in/yr, 1 in/yr, 5 in/yr, 10 in/yr, or 15 in/yr.
As shown in Table 4-3, the average annual precipitation at a particular site is a critical factor in
causing leakage for these three landfill designs. For most precipitation rates, the average
temperature (warm vs. cold) was not an important factor affecting the predicted infiltration rate.
However, for precipitation greater than 40 inches per year, leakage rates, and therefore DAFs, are
affected by climate. A review of the HELP model results indicates that the largest difference in
water balance between these locations lies in the evapotranspiration amount. That is, more of the
incoming precipitation evaporates in warmer climates than in cold, resulting in less infiltration into
the top of the landfill, and less leakage through the liner. While differences in evaporation also
occur between warm and cold climates with lower precipitation, differences are not seen in the
leakage rates. In climates with less rainfall, it is likely that evaporation forms a significant portion
of the overall water balance in both warm and cold climates simply because the total precipitation
is small. Therefore, the net infiltration into the landfill is similar.
2
Because the leakage rate predicted for a Subtitle D design approached zero inches per year, it was not
necessary to conduct MULTIMED modeling for sites with this design. It is assumed the performance standard will be
met at sites using a Subtitle D or equivalent design.
4-14
Draft: June 1998
-------
Table 4-2: MULTIMED Model Input Parameters
Parameter
Value
Reference
Aquifer Particle Diameter (mm)
0.004
Value for coarse clay /fine silt from Sharp-Hansen et al., 1990
Aquifer Bulk Density (g/cc)
1.67
SAIC, 1992
Depth of Aquifer (m)
78.6
SAIC, 1992
Aquifer Hydraulic Conductivity
(cm/s)
10 5
Mid-range value for unfractured limestone and dolomite (Freeze and
Cherry, 1979)
Aquifer Hydraulic Gradient
(unitless)
0.0309
SAIC, 1992
Aquifer Temperature °C
14.4
SAIC, 1992
pH of Aquifer (SU)
6.2
SAIC, 1992
Organic Carbon Content (fraction)
0.000001
SAIC, 1992
Radial distance from unit boundary
to POC (m)
1 or 152
Proposed performance standard
Infiltration Rate (Landfill Leakage
Rate) (m/yr)
See Table 4-3
Results of HELP model
Landfill Area (acres)
25
Same as input to HELP model
Recharge Rate (Total Precipitation)
(m/yr)
See Table 4-3
Same as input to HELP model
Draft: June 1998
4-15
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Table 4-3. Estimated DAFs for POC at 1 Meter and 152 Meters (From SAIC, 1997)
Climate
Conditions
Modeled with
HELP Model:
Precipitation
(in/yr) and
Temperature
Cement Plant Locations Matched to Modeled
Climate Conditions
(Facility Name, City, State, and Annual
Precipitation (in/yr))
HELP and MULTIMED Results for CKDLF Configurations in Non-Karst Settings
Baseline Design
Modified CKD Low Design
Modified CKD High Design
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
10
Warm and
Cold Climates
California Portland Cement, Colton, CA (9.58)
Mitsubishi Cement, Lucerne Valley, CA (15.42)
Riverside Cement Co., Oro Grande, CA (6.58)
National Cement, Lebec, CA (12.68)
Riverside Cement Co., Riverside, CA (15.63)
Royal Cement, Logandale, NV (5.81)
Southdown, Victorville, CA (5.51)
1
-------
Climate
Conditions
Modeled with
HELP Model:
Precipitation
(in/yr) and
Temperature
Cement Plant Locations Matched to Modeled
Climate Conditions
(Facility Name, City, State, and Annual
Precipitation (in/yr))
HELP and MULTIMED Results for CKDLF Configurations in Non-Karst Settings
Baseline Design
Modified CKD Low Design
Modified CKD High Design
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
Approximate
Post-Closure
Leakage Rate
predicted by
HELP (in/yr)
DAF
predicted by
MULTIMED
40b
Cold Climate
Dragon Products, Thomaston, ME (45.77)
Lone Star Industries, Oglesby, IL (37.24)
15
-------
Five climate scenarios were modeled using MULTIMED based on the approximate HELP
leakage rates predicted for eight climate scenarios. The warm and cold climate scenarios with
average precipitations of 10, 29 and 55 inches/year were combined based on their similar leakage
rates for the three landfill designs. Two POCs located at 1 and 152 meters (3 and 500 feet)
downgradient from the landfill were evaluated in the MULTIMED simulations. Because
MULTIMED is a steady state model and no adsorption is assumed, the depth to ground water is
not a factor in computing leachate attenuation at the POC. The model assumes that
hydrodynamic dispersion (i.e., dilution) in the saturated ground water system is the only physical
process resulting in contaminant attenuation. The DAFs resulting from these simulations are
presented in Table 4-3. As a point of reference, cement plants that waste net CKD and are
located in non-karst areas are matched in this table according to the appropriate climate.
As described in the following section, the DAFs predicted by MULTIMED can be applied to
known leachate constituent concentrations in order to determine whether the MCLs for these
contaminants will be exceeded at a POC.
4.3.4 Using MULTIMED DAFs to Evaluate CKDLF Designs Relative to the Performance
Standard in Non-Karst Hydrogeologic Settings
Using the DAFs calculated by MULTIMED, an analysis was performed to determine which (if
any) of the three landfill design configurations (Baseline, Modified CKD Low, or Modified CKD
High) can be expected to meet the performance standard, assuming the landfill is constructed in a
hydrogeologic environment in which Darcy's law is valid. To estimate the concentration of the
constituent of concern in the receptor or POC well (CRW), the leachate concentration (CL) is
divided by the DAF for the landfill design being evaluated:
Crw = CL / DAF (Equation 4.1)
The result is then compared to the MCL to determine whether the performance standard can be
achieved. Alternatively, one could estimate the minimum DAF required to meet the performance
standard by setting the receptor well concentration equal to the MCL and rearrange Equation 4.1
to:
DAF = Cl/MCL (Equation 4.2)
Next, a contaminant was selected along with an assumed leachate concentration. To select a
contaminant, TCLP data were reviewed from the 1994 Notice of Data Availability (NOD A)
"Human Health and Environmental Risk Assessment in Support of the Report to Congress on
Cement Kiln Dust" (USEPA, 1994). The report includes a composite of "as managed" TCLP
results from three data sources: (1) EPA's 1992 and 1993 sampling analyses, (2) the 1990 PCA
survey responses, and (3) EPA's 1992 request for additional information under Section 3007 of
the Resource Conservation and Recovery Act (RCRA). Upper 95th percentile levels derived
from the above-referenced data were reported as follows: antimony concentrations at 17 times
Draft: June 1998
4-18
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the MCL, lead at 109 times the MCL, and thallium at 650 times the MCL. Upper 95th percentile
data were used to generate an upper-bound estimate of the DAF required for a landfill design to
meet the proposed performance standard in non-karst environments.
Thallium was selected as the constituent of concern because it has the highest upper 95th
percentile TCLP leachate concentration relative to its MCL. Using Equation 4.2, a DAF of 650 is
required to meet the performance standard. Landfill designs with predicted DAFs greater than
650 should be capable of achieving a performance standard of no exceedance of MCLs at 150
meters downgradient of the CKD landfill for all constituents of concern. Designs which yield a
DAF of less than 650 are considered unacceptable under the stated assumptions.
Using the data presented in Table 4-3, each of the 18 "non-karst" facilities in the table was
assigned a landfill design capable of yielding a DAF of 650 or greater. If one of the three
alternative designs (i.e., Baseline, Modified CKD High, Modified CKD Low) could not achieve a
DAF of at least 650 at the POC, then the Subtitle D design was assigned by default. The results
of this analysis are summarized in Table 4-4.
4.3.5 Summary Results of Application of the Decision Framework to the Cement Plant
Database
The results of the application of the decision framework to the cement plant database are
summarized in Table 4-5.
Draft: June 1998
4-19
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Table 4-4. Results of Landfill Evaluation for Cement Plants in Non-Karst Areas
(Assuming a Minimum DAF of 650 is Required to Meet the Performance Standard — see Sec. 4.3.4)
Cement Plant Name/Location
Baseline Design
Modified CKD Low Design
Modified CKD High Design
Landfill
Design
Selected
POC=152m
POC=lm
POC=152m
POC=lm
POC=152m
POC=lm
Ash Grove Cement Co, Louisville, NE
X
X
~
X
~
X
CKD Low
Ash Grove Cement, Chanute, KS
X
X
X
X
~
X
CKD High
California Portland Cement, Colton, CA
X
X
~
X
~
X
CKD Low
Dragon Products, Thomaston, ME
X
X
X
X
X
X
Subtitle Da
Holnam Inc., Ada, OK
X
X
X
X
~
X
CKD High
Lafarge, Alpena, MI
X
X
~
X
~
X
CKD Low
Lafarge, Fredonia, KS
X
X
X
X
~
X
CKD High
Lone Star Industries, Oglesby, IL
X
X
X
X
X
X
Subtitle Da
Mitsubishi Cement, Lucerne Valley, CA
X
X
~
X
~
X
CKD Low
Monarch Cement Co., Humboldt, KS
X
X
X
X
~
X
CKD High
National Cement, Lebec, CA
X
X
~
X
~
X
CKD Low
Puerto Rico Cement Co., Ponce, PR
X
X
X
X
~
X
CKD High
Riverside Cement Co., Riverside, CA
X
X
~
X
~
X
CKD Low
Riverside Cement Co., Oro Grande, CA
X
X
~
X
~
X
CKD Low
RMC Lonestar, Davenport, CA
X
X
~
X
~
X
CKD Low
Royal Cement, Logandale, NV
X
X
~
X
~
X
CKD Low
San Juan Cement, Dorado, PR
X
X
X
X
~
X
CKD High
Southdown, Victorville, CA
X
X
~
X
~
X
CKD Low
POC = "point of compliance", K = Unacceptable design based on MULTIMED DAF, ~ = Acceptable design based on MULTIMED DAF.
None of the proposed landfill designs (Baseline, Modified CKD Low, or Modified CKD High) were found acceptable for this facility, therefore, a default
Subtitle D design was recommended.
Draft: June 1998
4-20
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Table 4-5. Predicted Ground water Controls Required at Cement Plants
Predicted Ground Water Controls
Number of
Facilities
Percent
of Total
1. No Ground Water Controls Required
36
32.7
2. Baseline Landfill (see note)
0
0.0
3. Modified CKD Low Landfill Design (see note)
10
9.1
4. Modified CKD High Landfill Design (see note)
6
5.5
5. Subtitle D Default Landfill Design
53
48.2
6. Alternative Landfill Design Required (per
proposed §259.30(g)) or On-site Land Disposal
Prohibited
5
4.5
Total
110
100.0
Note: Assumes a point of compliance (POC) at 150 meters (500 ft.) downgradient of the CKD management unit.
4.3.6 Assumptions and Limitations
The decision framework assumes facilities that currently land dispose CKD will continue to do so
after the CKD rule is implemented. Due to the additional costs associated with the design and
operation of a new landfill, it is possible that some (and possibly most) facilities will attempt to
implement recycling and/or reuse measures as a means to avoid or minimize land disposal of
CKD. The decision framework, as currently structured, does not account for this possibility.
Accordingly, the decision framework might overestimate the number of facilities that will continue
to land-dispose CKD and will require ground water controls.
4.4 Summary and Conclusions
As part of the rulemaking effort, EPA requires estimates of the ground-water controls likely to be
implemented at cement plants in response to the regulation. To predict the ground-water
controls, if any, that will be required at each cement plant in the U.S., a decision framework was
developed based on the ground-water controls currently under consideration by EPA for inclusion
in the proposed rule for management of CKD. A range of possible ground-water controls was
then established, each of which could be an end point upon application of the decision framework.
The ground water controls include: (1) no landfill required for facilities that do not land dispose
CKD; (2) a baseline landfill; (3) a modified CKD Low design (4) a modified CKD High design;
(5) the Subtitle D default design; and (6) alternative landfill design or off-site land disposal of
CKD for facilities located in mature karst areas subject to subsidence. Engineering analyses,
HELP modeling, and MULTIMED modeling were conducted to assess the adequacy of the
proposed designs. The cement plant database was updated to include new information on CKD
generation rates, CKD management practices, and site-specific hydrogeologic information. The
Draft: June 1998
4-21
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decision framework was then applied to the database to predict the ground-water protection
measures required at each of the 110 cement plants in the database.
The results of the analysis indicate that 36 cement plants (33%) will not require any ground water
controls because they do not waste net CKD. Fifty-three cement plants (48%) are likely to
require the Subtitle D default design for their CKD landfills because they land-dispose CKD and
they are located in areas of karst or in climate settings that might allow CKD leachate to enter the
ground water with inadequate dilution and attenuation. Sixteen cement plants that land-dispose
CKD will require either a "Modified CKD Low" or "Modified CKD High" design. MULTIMED
modeling results indicate the Baseline CKD landfill configuration (which represents current
industry practice) is not acceptable for use at any cement plant under the assumptions stated in the
analysis. At five (5) cement plants (4.5%), an alternative landfill design will be required or on-site
land disposal likely will not be feasible due to the presence of mature karst features and the high
potential for subsidence and/or landfill failure.
Draft: June 1998
4-22
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References
American Portland Cement Association (APCA), 1995. Electronic database entitled "1995
American Portland Cement Association Survey, Question 2.01 - CKD Generation Rates".
Freeze, R.A, and J.A. Cherry, 1979 Groundwater. Prentice-Hall, Inc., Englewood Cliffs, New
Jersey.
ICF Consulting Group (ICF), 1995a. Memo to B. Schoenborn (USEPA) from K. Cornils, E.
Ijjasz, B. Vanatta and P. Soyka (ICF Incorporated), entitled "Potential Impacts on Ground
Water of the Cement Industry's Proposed CKD Management Plan". July 14, 1995. (EPA
Contract No. 68-W4-0030, Work Assignment 9).
NOAA, 1992, Monthly Station Normals of Temperature, Precipitation, and Heating and Cooling
Degree Days, 1961-1990, National Oceanic and Atmospheric Administration, National
Climatic Data Center, Asheville, NC.
Science Applications International Corporation (SAIC), 1992. Evaluation of Subtitle D Landfill
Designs Using the HELP and MULTIMED Models - A Tutorial. Submitted to USEPA
Office of Solid Waste, Washington D.C. under EPA Contract No. 68-W0-0025
(5/26/92).
Science Applications International Corporation (SAIC), 1997. HELP Modeling to Assess the
Incremental Effectiveness of Subtitle C and D Landfill Designs Over a Baseline CKD
Landfill. Submitted to USEPA Office of Solid Waste, Washington D.C. under EPA
Contract No. 68-W4-0030 (1/24/97).
Sharp-Hansen, S., C. Travers, P. Hummel, and T. Allison 1990. A Subtitle D Landfill
Application Manual for the Multimedia Exposure Assessment Model (MULTIMED).
Prepared for the USEPA, Athens GA. August 1990. 209 pp.
Sterner, Ray. 1994. The Climate of Pennsylvania. John Hopkins University Applied Physics
Laboratory
USEPA, 1994. Notice of Data Availability, Human Health and Environmental Risk Assessment
in Support of the Report to Congress on Cement Kiln Dust. EPA Office of Solid Waste.
August 31, 1994, Revised per Federal Register Notice of October 11, 1994.
USEPA, 1993a. Report to Congress on Cement Kiln Dust, Volume II Methods and Findings.
EPA Office of Solid Waste. December 1993.
USEPA, 1993b. Solid Waste Disposal Facility Criteria, 40 CFR Part 258, Technical Manual.
EPA Office of Solid Waste. November 1993.
Draft: June 1998
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USEPA, 1993c. Supplemental Analysis on Potential Risks to Human Health and the Environment
from Large-Volume Coal Combustion Waste. July 30, 1993.
Draft: June 1998
4-24
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Chapter 5: Summary of Proposed CKD Waste Management Standards for Protection of
Ground Water Resources
This chapter provides a summary of EPA's proposed standards for the design and operation of
CKDLF units. A CKDLF unit is defined in the proposed rule as a discrete area of land or an
excavation that receives CKD waste, and that is not a land application unit, surface
impoundment, injection well, or waste pile1. A CKDLF unit may receive other types of non-
hazardous industrial wastes, such as kiln brick, construction debris, mining overburden or
other industrial waste. A CKDLF unit may be a new CKDLF unit, an existing CKDLF unit2
or a lateral or vertical expansion of an existing unit. The standards to control releases to
ground water at CKDLF units include location restrictions (Section 5.1), performance
standards for landfill liners (Section 5.2), a default technical design criteria for CKDLF units
(Section 5.3), and technical requirements for ground water monitoring and corrective actions
(Section 5.4).
5.1 Location Restrictions
The Agency is proposing six location restrictions applicable to CKDLF units. The proposed
restrictions include: a prohibition on disposal of CKD below the natural water table (Section
5.1.1); restrictions on placement of CKDLF units in floodplains (Section 5.1.2), wetlands
(Section 5.1.3), fault areas (Section 5.1.4), seismic impact zones (Section 5.1.5), and unstable
areas, particularly unstable areas in karst terrain (Section 5.1.6). With one exception (i.e., the
prohibition against disposal of CKD below the water), the Agency is not proposing an absolute
prohibition against siting CKDLFs at these locations; however, all of the proposed locations
restrictions require the owner or operator to demonstrate to the State (or in unauthorized
States, the EPA Regional Administrator) that they meet specific criteria. In absence of
evidence of information to the contrary, EPA is proposing location standards for floodplains,
fault areas, seismic impact zones, and unstable areas that are similar to those specified under
RCRA Subtitle C for hazardous waste facilities. Because EPA has found increased risks to
human health and the environment from CKD disposal at karstic sites, additional standards
have been proposed for CKDLF units located in karst terrain (see Section 5.1.6). Nothing in
the proposed rule is intended to affect any requirements that facilities may have to comply with
under other programs, such as §404 of the Clean Water Act which affects disposal in wetlands.
^and application units are facilities at which waste is applied onto or incorporated into the surface soil;
surface impoundment are facilities designed to hold an accumulation of liquid wastes or liquids containing free
liquids; injection wells are wells into which fluids are injected.
An existing CKDLF unit means any CKD waste landfill unit that is receiving CKD as of 90 after
promulgation of the proposed rule.
Draft: June 1998
-------
5.1.1 Prohibition of CKD Disposal Below the Natural Water Table
EPA is proposing to ban disposal of CKD in units below the natural water table. The natural
water table is defined as the natural level at which water stands in a shallow ground water well
open along its length and penetrating the surficial deposits just deeply enough to encounter
standing water at the bottom. For the purpose of this standard, this level is uninfluenced by
ground water pumping or other engineered activities. At some CKDLF units, the Agency has
observed that facility owners artificially lower the natural water table to minimize contact of
CKD with ground water. In the case where a site is dewatered (i.e., the water table is
artificially lowered) and CKD is disposed below the natural water table, ground water could
rise and flow into the CKD disposal unit if the site were abandoned and pumping discontinued.
Financial assurances for unit closure would not be sufficient to maintain site dewatering
activities indefinitely or would be inadequate to prevent contact of ground water with CKD
waste. This would represent an increased risk to human health and the environment due to the
subsequent mobilization of CKD constituents within the ground water system. Accordingly,
the Agency is proposing to prohibit disposal of CKD below the natural water table.
The Agency has identified at least seven incidents where direct CKD contact with ground
water has resulted in degradation of ground water. These incidents are summarized in Table
5-1. At these sites, ground water appears to have saturated portions of waste CKD disposed
below the natural water table, mobilized CKD contaminants into the aqueous phase, and
transported these contaminants to downgradient areas. The Agency's proposed prohibition
against CKD disposal below the natural water table minimizes releases to ground water caused
by direct contact of CKD with ground water. CKD contaminants will be less likely to migrate
off-site if there is no potential for the CKD waste to contact the saturated ground water system.
Table 5-1. Damage Cases due to CKD Disposal Below the Natural Water Table
CKD Site,
Location
CKD Disposal
Practice
Environmental Impact
Holnam, Inc.,
Mason City,
Iowa
CKD was disposed of in a
former limestone quarry
(West Quarry) which was
about 40 feet deep and
150 acres in size.
The quarry became filled with ground water and rain
water subsequent to the suspension of quarrying
operations. Ground water flow in the CKD fill and
fractured bedrock transported CKD constituents (Cd,
total alkalinity, S04, Na, K, and high pH) from the
quarry and resulted in a fish kill in Calmus Creek.
Maximum concentrations of Sb, Cd, Cr, Pb, Ni in
ground water exceeded federal drinking water standards
(USEPA, 1997a).
Draft: June 1998
5-2
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CKD Site,
Location
CKD Disposal
Practice
Environmental Impact
Lehigh
Portland
Cement Co.,
Mason City,
Iowa
CKD was disposed of in
former limestone quarries
(Arch Pond, Blue Waters
Pond, Area C Pond).
Quarries became filled with ground water and rainwater
following the suspension of excavation operations.
Conduit ground water flow in the CKD fill and fractured
bedrock transported CKD constituents (As, Pb, S04,
Na, K, and high pH) into the shallow ground water
system (USEPA, 1997b).
Lehigh
Portland
Cement Co.,
Metaline Falls,
Washington
CKD was disposed of in
an unlined waste pile
covering about 7.2 acres
located in the Sullivan
Creek floodplain
Subsequent to disposal ground water levels rose up into
the CKD and mobilized waste CKD constituents (As,
Cd, Cr, Ni, Pb, Tl, and high pH) into the underlying
ground water system and/or adjacent seeps and
drainages. Percolation of storm water run-on through
the pile was also a factor in mobilizing CKD constituents
in ground water (USEPA, 1997c).
Medusa
Cement Co.,
Charelvoix,
Michigan
Since 1967, CKD has
been disposed of in nine
piles which are less than
0.5 miles from Lake
Michigan.
The lower portions of CKD Piles 2,4, and 9 appear to
lie within the ground water table. Ground water seeps
adjacent to Lake Michigan contained elevated levels of
pH (up to 12.1 SU) and specific electrical conductance
(up to 5750 umhos/cm). In spite of site dewatering
activities, ground water flows through the piles toward
Lake Michigan have resulted in CKD contaminated
waters emerging as shoreline seeps (RTM 1996).
Portland
Cement Co.,
Salt Lake City,
Utah
CKD and chromium-
bearing refractory bricks
were dumped as fill
material on a 70-acre site
in a floodplain adjacent to
the Jordan River Surplus
Canal in order to improve
site drainage.
Subsequent to disposal ground water levels rose up into
the CKD and mobilized CKD waste constituents (As,
Cd, Cr, Pb, Mo, and high pH) into the underlying
ground water system (USEPA, 1997d).
Signal
Mountain
Cement Co.,
Chattanooga,
Tennessee
CKD was landfilled on-
site in an old abandoned
limestone quarry and
adjacent wall cavities
connected to
underground caverns
beneath Signal Mountain.
Ground water (pH levels in excess of the Federal
Secondary Drinking Water Standard) flowed through the
caverns and combined with landfill surface runoff (pH
levels in excess of the RCRA hazardous characteristic of
corrosivity) to discharge into a tributary of the Tennessee
River. Measurements of pH in ground water from the
quarry cavities were ranged from 12.0 to 12.27 SU
(USEPA, 1997e).
Draft: June 1998
5-3
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CKD Site,
Location
CKD Disposal
Practice
Environmental Impact
Southdown,
Inc., Fairborn
Ohio
CKD and chromium-
bearing refractory bricks
were disposed of in
former limestone quarries
and in unlined landfills
adjacent to wetlands and
the Mud Run.
A ground water seep located at the toe of Landfill #6
contained CKD constituents (As, Fe, Hg, Ni, Se, Zn,
and pH) above drinking water standards. The
uppermost aquifer, which consists of gravelly glacial
deposits, is an important drinking water aquifer for the
City of Fairborn (USEPA, 1993a).
5.1.2 Floodplains
EPA is proposing a restriction on the placement of CKDLF units in a 100-year floodplain.
Under the proposed standard, the CKDLF unit must not restrict flow of the 100-year flood,
reduce the temporary water storage capacity of the floodplain, or during flooding, have solid
waste washout resulting in a hazard to human health and the environment. A floodplain is
defined as the lowland and relatively flat areas adjoining inland and coastal waters, including
flood-prone areas of offshore islands, that are inundated by the 100-year flood. A 100-year
flood means a flood that has a 1-percent or greater chance of recurring in any given year or a
flood of a magnitude equaled or exceeded once in 100 years on the average over a significantly
long period. To determine whether a CKDLF is in the 100-year floodplain, owners and
operators should use flood insurance rate maps (FIRMS) developed by the Federal Emergency
Management Agency. If a new or existing CKDLF unit is located in a 100-year floodplain, it
must be designed and operated to prevent potential flooding damages including: (1) rapid
transport of hazardous constituents by floodwater resulting in degradation of water quality
downstream: (2) restriction of floodwater flow, causing greater flooding upstream; and (3)
reduction of the storage capacity of the floodplain, since this may cause more rapid movement
of floodwater downstream, resulting in higher flood levels and greater flood damages
downstream. Site-specific information should be used to evaluate whether a facility has met
this standard. The owner or operator must place a demonstration that the facility has met this
standard in the operating record and notify the State Director that the demonstration has been
placed in the operating record.
5.1.3 Wetlands
The Agency is proposing that no new CKDLF unit can be placed in wetlands unless the owner
or operator makes specific demonstrations to the State or (in unauthorized States) to the EPA
Regional Administrator, that the new unit: (1) will not result in "significant degradation" of
the wetland as defined in the Clean Water Act §404 (b)(1) guidelines and published at 40 CFR
Part 230; and (2) will meet other requirements derived from the §401 (b)(1) guidelines.
Wetlands are defined by 40 CFR §232.2(r) as: "..areas that are inundated or saturated by
surface or ground water at a frequency and duration sufficient to support, and that under
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normal circumstances do support, a prevalence of vegetation typically adapted for life in
saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar
areas."
Before siting a CKDLF unit in a wetland, the owner or operator must meet five requirements
to qualify for a waiver to the ban. These requirements involve:
• conducting a test which shows that there are no practicable alternatives to siting
the proposed landfill in the wetland (§230.10(a));
• performing an assessment of compliance with other applicable laws
(§230.10(b)). Specifically, the owner or operator will be required to show that
the construction and operation of the CKDLF unit will not:
(i) cause or contribute to violations of any applicable State water quality
standard,
(ii) violate any applicable toxic effluent standard or prohibition under
Section 307 of the Clean Water Act,
(iii) jeopardize the continued existence of endangered or threatened
species or result in the destruction or adverse modification of a critical
habitat, protected under the Endangered Species Act of 1973, and
(iv) violate any requirement under the Marine Protection, Research, and
Sanctuaries Act of 1972 for the protection of a marine sanctuary.
• performing an assessment of aquatic degradation (§230.10(c)) to establish that
the CKDLF unit will not cause or contribute to significant degradation of
wetlands:
• evaluating steps taken to minimize the adverse effects of discharge (§230.10(d))
to prevent a net loss of wetlands: and
• assessing whether sufficient information is available to determine if the first four
requirements are met.
The guiding principle is that discharges should not be allowed unless the owner or operator can
demonstrate that such discharges are unavoidable and will not cause or contribute to significant
degradation of wetlands.
5.1.4 Fault Areas
EPA proposes that no new CKDLF units can be sited within 60 meters (200 feet) of a fault
that has experienced displacement in Holocene time (within the last 10,000 to 12,000 years),
unless a demonstration is made to the State or (in unauthorized States) to the EPA Regional
Administrator that an alternative setback distance of less than 60 meters will prevent damage to
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the structural integrity of the CKDLF unit, and will be protective of human health and the
environment. A fault is a fracture or a zone of fractures in any material along which
movement has occurred and strata on each side have been displaced relative to each other.
EPA believes that motion along faults, as well as secondary effects of shaking such as ground
or soil failure, may adversely affect the structural integrity of CKDLF units, and that a 60-
meter buffer zone is necessary to protect engineered structures from seismic damages.
Regional geologic maps of Holocene age faults are published by the U.S. Geological Survey
(USGS, 1978).
For locations where a fault zone has been subject to movement since the USGS maps were
published in 1978, a geological reconnaissance of the site and surrounding areas may be
required to map fault traces and to determine the faults along which movement has occurred in
Holocene time. Site fault characterization studies may be necessary to support a demonstration
for a setback of less than 200 feet. Site fault characterization studies would include obtaining
information on any lineaments (linear features) that suggest the presence of faults within a
3,000-foot radius. This information could be based on:
• A review of available maps, logs, reports, scientific literature, or insurance
claim reports;
• An aerial reconnaissance of the area within a five-mile radius of the site,
including aerial photo analysis; or
• A field reconnaissance that includes walking portions of the area within 3,000
feet of the site.
A more detailed site investigation including exploratory trenching is warranted if the site
characterization study indicates that a fault or set of faults is situated within 3,000 of the
proposed unit. Guidance for conducting detailed fault investigations is found in "Solid Waste
Disposal Facility Criteria, Technical Manual" (USEPA, 1993b) and "Guidance Document,
Seismic Considerations, Hazardous Waste Management Facilities" (MITRE, 1980).
5.1.5 Seismic Impact Zones
The Agency proposes that any new CKDLF unit located in a seismic impact zone be designed
to resist the maximum horizontal acceleration in lithified material for the site. The design
features affected include all containment structures (i.e., liners, leachate collection systems,
final landfill cover systems, and surface water control systems). Seismic impact zones are
defined as areas having a ten percent or greater probability that the maximum expected
horizontal acceleration in lithified material for the site, expressed as a percentage of the earth's
gravitational pull (g), will exceed 0.10 g in 250 years. The term 'lithified material' refers to
any consolidated or coherent, relatively hard, naturally occurring aggregate composed of one
or more minerals (e.g., granite, shale, marble, sandstone, limestone, etc.). This definition
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explicitly excludes loose, incoherent masses such as soils or regolith, and man-made materials
such as fill, concrete or asphalt. Maps depicting the potential seismic activity across the
United States at a constant probability level have been prepared by the United States
Geological Survey (Algermissen et al., 1976).
To determine the maximum horizontal acceleration of the lithified earth materials for the site,
owners or operators should review the seismic 250-year interval maps in "Probabilistic
Earthquake Acceleration and Velocity Maps for the United States and Puerto Rico"
(Algermissen et al., 1991). Information on the location of earthquake epicenters and
intensities may be available through State Geologic Surveys or the National Earthquake
Information Center, located at the Colorado School of Mines in Golden, Colorado.
Studies indicate that during earthquakes, limited downslope movement of cover soils,
cracking, and differential displacements tend to be produced at landfills rather than massive
slope failures (Anderson and Kavazanjian, 1995). Stresses created by surficial failures can
affect the liner and final cover systems as well as the leachate and gas collection and removal
systems. Tensional stresses within the liner can result in fracturing of the soil liner and/or
tearing of the flexible membrane liner. If due to a lack of suitable alternatives a site is chosen
that is located in a seismic impact zone, a demonstration must be made to the Director that the
design of the unit's structural components (e.g., liners, leachate collection, final covers, run-
on and run-off systems) will resist the maximum horizontal acceleration in lithified materials at
the site. As part of the demonstration owners/operators must:
• Determine the expected peak ground acceleration from a maximum strength
earthquake that could occur in the area,
• Determine the site-specific seismic hazards such as soil settlement, and
• Design the facility to withstand the expected peak ground acceleration.
The design of slopes, leachate collection system, and other structural components should have
built-in conservative design factors. Additional, redundant precautionary measures should be
designed and built into various landfill systems. In determining the potential effects of seismic
activity on a structure, an engineering evaluation should examine soil behavior with respect to
earthquake intensity. Guidance for conducting such an evaluation is found in "Solid Waste
Disposal Facility Criteria, Technical Manual" (USEPA, 1993b).
5.1.6 Unstable Areas Including Karst Terrains
EPA is also proposing that owners and operators of new and existing CKDLF units located in
unstable areas must demonstrate to the State (or, in unauthorized States, the EPA
administrator) the structural integrity of the unit. This demonstration must show that
engineering measures have been incorporated into the unit's design to mitigate the potential
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adverse structural impacts on the structural components of the unit that may result from
subsidence, slope failure, or other mass movements in unstable areas. For purposes of this
section, structural components include liners, leachate collection systems, and final covers.
The EPA is particularly concerned with CKDLF units located in areas of karst terrain. More
than one half of all cement plant sites are estimated to be located in karst terrains with a
potential to be underlain by karst aquifers with conduit flow characteristics. The potential for
off-site CKD leachate migration in karst aquifers with a strong component for conduit flow is
high. As a result, owners or operators of a new or existing CKDLF unit, or a lateral
expansion located in a karst hydrogeologic setting must demonstrate that engineering measures
have been incorporated into the landfill unit's design to ensure that the integrity of the
structural components of the unit will not be disrupted. These structural components include
liners, leachate collection systems, final covers, run-on/run-off systems, and any other
component used in the construction and operation of the CKD landfill unit that is necessary for
the protection of human health and the environment.
Before construction of a CKD in carbonate terrain, the owner/operator shall be required to
verify and certify whether the facility is situated in a karst terrain. Verification of a karst
terrain may include a review of the available literature, and if the literature review is
inconclusive, a basin-wide field study. This field study is required to compile an inventory of
karst features and identify all potential springs from which ground water passing beneath the
CKD landfill unit may discharge even if the discharge points of the basin extend beyond the
facility boundary. Factors to be considered during the inventory include:
• on-site or local geologic or geomorphologic features, especially those features
indicative of a karst hydrogeologic setting; and
• on-site or local soil conditions that may result in significant differential settling,
collapse, or puncture of the landfill liner, and
• on-site or local anthropogenic features or events (both surface and subsurface)
that may impact the integrity of the CKDLF unit or ground water flow from the
site.
To conduct the site characterization field study, the facility must locate background and
intermediate sampling locations, and downgradient springs or ground water monitoring wells.
If the site is certified to be located in karst terrain by an independent professional ground water
scientist, data collected from these locations must be incorporated into a determination of on-
site hydrology, including the character and direction of ground water flow and points of
discharge for the karst ground water basin the facility may affect. Such a determination will
require:
• tracer studies to verify ground water flow path,
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• the regular monitoring of chemographs and hydrographs of springs and
monitoring wells, and
• the development of a sampling strategy capable of detecting releases from the
CKDLF unit. The sampling strategy must be based on the unique fate and
transport characteristics of the toxic constituents in CKD and the hydrology of
the karst aquifer.
The requirement for a karst ground water investigation may be suspended if the owner or
operator of the facility can demonstrate that there is no potential for migration of hazardous
constituents from the CKD landfill unit to the uppermost aquifer during the active life of the
unit and the post-closure care period (proposed 40 CFR 259.30(b)). This demonstration must
be certified by a qualified ground water scientist, approved by the State and based upon:
• site-specific field collected measurements, sampling, and analysis of physical,
chemical, and biological processes affecting contaminant fate and transport, and
• contaminant fate and transport predictions that maximize contaminant migration
and consider impacts on human health and the environment.
5.2 Performance-Based Standard for Protection of Ground Water
After evaluating a range of possible performance standards as discussed in Chapters 3 and 4,
and considering the need for a tailored and flexible approach for the protection of ground
water, the Agency is proposing a performance-based design standard that is similar to the
RCRA Subtitle D performance standard found in 40 CFR 258.30(c)(1). This performance-
based standard would apply to the metal constituents (antimony, arsenic, barium, beryllium,
cadmium, chromium (total), lead, mercury, nickel, selenium, silver, thallium, and vanadium).
For each constituent, the standard would be as follows: (1) if available, the maximum
contaminant level (MCL) established under § 1412 of the Safe Drinking Water Act (See 40
CFR Part 141); (2) for constituents with concentration levels lower than background, the
background level; and (3) for constituents with no MCLs, an alternative risk-based number or
appropriate level established by the EPA Regional Administrator.
MCLs would be measured in ground water from the uppermost aquifer at the point of
compliance, defined as the closest practical distance from the unit boundary, or at an
alternative point chosen by the State. The alternative point of compliance must be on facility
property and be no more than 150 meters from the unit boundary (proposed 40 CFR
259.30(f)). In allowing for an alternative point of compliance, the Agency's rationale is to
allow greater flexibility for a State to set design requirements based on site-specific factors. In
determining the relevant POC, the following factors shall be considered:
• the hydrogeologic characteristics of the facility and surrounding land;
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• the volume and physical and chemical characteristics of the leachate;
• the quantity, quality, and direction of flow of ground water;
• the proximity and withdrawal rate of ground water users;
• the availability of alternative drinking water supplies;
• the existing quality of the ground water, including other sources of
contamination and their cumulative impacts on the ground water, and whether
the ground water is currently used or reasonably expected to be used for
drinking water; and
• public health and safety effects (proposed 40 CFR 259.30 (f)).
5.3 Default Technical Design Criteria for CKDLF Units
EPA is proposing that design criteria similar to that for municipal solid waste landfills
(MSWLFs) under the Subtitle D program (Solid Waste Disposal Facility Criteria, 56 FR
50978, October 9, 1991) be adopted for CKDLF units with modifications for ground water
monitoring (see section 5.4.1) and remediation. As EPA demonstrated using the HELP model
(See Chapter 3) and studying management of waste similar to CKD (See Chapter 6), these
default design criteria are considered sufficient to meet the CKDLF performance standards
discussed in Section 5.2. It is recognized that for some sites alternative designs can be
demonstrated to meet the performance based standards. In the absence of an approved
alternative design, the default design criteria would apply to any new CKD waste management
unit or lateral extension. The default technical design criteria for CKDLF units require a
composite bottom liner and a leachate collection and removal system (LCS) that is designed
and constructed to maintain less than a 30 cm depth of leachate over the liner. The composite
liner must consist of two components: an upper flexible membrane liner (FML) with a
minimum thickness of 30-mil, and a lower component consisting of at least two feet of
compacted clay with a hydraulic conductivity of no more than 1 x 107 cm/sec. FML
components consisting of high density polyethylene (HDPE) shall be at least 60-mil thick, and
must be installed in direct and uniform contact with the compacted soil component (proposed
40 CFR 259).
The Agency believes that this proposed default design criteria will be protective of ground
water resources. Liners will prevent leachate from seeping from the landfill and entering the
aquifer. Functionally, both the FML and lower clay component are necessary to retard the
migration of contaminants; the FML would impede the flow of leachate into subsoil, and the
compacted clay component would adsorb and attenuate pollutants. A LCS is necessary to
relieve the hydraulic pressure within the landfill which could drive leachate migration through
the base of the landfill.
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When designing a CKD landfill unit, in addition to the proposed design criteria, the owner or
operator shall consider at least the following factors:
• the hydrogeologic characteristics of the facility and surrounding land, especially
the presence of karst terrain (see section 5.1.2);
• the climatic factors of the area; and
• the volume and physical and chemical characteristics of the leachate (proposed
40 CFR 259.30 (e)).
5.4 Proposed Technical Requirements For Ground Water Monitoring
The proposed technical requirements for ground water monitoring at CKD disposal units are
based on those already promulgated under 40 CFR Part 258 (for MSWLFs) and 40 CFR Part
264 (for hazardous waste management units). In developing these standards, EPA also
considered a draft proposal submitted to the Agency from the cement industry entitled Cement
Kiln Dust Management Practices (Portland Cement Association, 1995). The proposed
requirements have been tailored to address the characteristics of CKD and provide sufficient
flexibility to allow effective implementation by States. EPA's proposed standards for ground
water monitoring at CKDLFs include provisions for:
• ground water monitoring well design, construction and development (Section
5.4.1),
• ground water sampling and analysis requirements (Section 5.4.2),
• statistical analysis of ground water monitoring data (Section 5.4.3),
• detection monitoring (Section 5.4.4),
• assessment monitoring (Section 5.4.5),
• assessment of corrective measures (Section 5.4.6),
• selection of remedy (Section 5.4.7), and
• implementation of corrective action (Section 5.4.8).
All owners and operators of new or existing CKDLF units or lateral expansions are required to
comply with these standards. However, limited waivers may be granted to owners or
operators who can demonstrate that a waste management unit is located above a hydrogeologic
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setting that will prevent the migration of CKD constituents of concern to ground water during
the active life and closure and post-closure periods of the unit.
5.4.1 Ground Water Monitoring Well Design and Construction
As a part of the performance standard for new and actively managed CKDLF units, and lateral
expansions, the EPA proposes the installation of ground water monitoring systems similar to
those described in 40 CFR 258.51 for MSWLFs. These ground water monitoring systems
shall be used throughout the active, closure, and post-closure periods of the unit.
The proposed standards require that implementation of a ground water monitoring program
would be required for new CKDLF units prior to accepting CKD waste. Ground water
monitoring wells are required to be designed according to the following criteria:
• The ground water monitoring system must include, at a minimum, one up-
gradient and three down-gradient wells.
• The relevant point of compliance for down-gradient wells must be on the
property of the CKDLF unit owner. If obstructed by physical barriers from
being located on-site, the ground water monitoring system shall be installed at
the hydraulic down-gradient position closest to the point of compliance where
contaminated ground water in the uppermost aquifer can be detected.
• The ground water monitoring system must be capable of ascertaining the quality
of background ground water that has not been affected by leakage from the unit,
and assessing the quality of ground water passing the relevant point of
compliance. As discussed in Section 8.1.2, this may be a formidable task in
karst terrain.
• The number, spacing and depths of monitoring systems shall be dependant on
aquifer thickness, ground water flow rate, ground water flow direction including
seasonal and temporal fluctuations in ground water flow. Other factors to be
considered include: the thicknesses, stratigraphy, lithology, hydraulic
conductivities, porosities, and effective porosities of saturated and unsaturated
geologic units, and fill comprising the uppermost aquifer and the confining unit
forming the lower boundary of the uppermost aquifer;
• Where the facility has several units, the owner or operator may install a multi-
unit ground water monitoring system instead of separate ground water
monitoring systems for each CKD landfill unit.
• Each ground water monitoring system be certified as adequate by a qualified
ground water scientist or approved by the State;
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Monitoring wells must be constructed in a manner that maintains the integrity of the
monitoring well bore hole. The casing must be screened or perforated and packed with gravel
or sand, where necessary, to enable collection of ground water samples. The annular space
above the sampling depth must be sealed to prevent contamination of samples and the ground
water. Ground water monitoring plans, monitoring well locations, and points of compliance
for CKDLF units must be approved by the State Director prior to implementation.
5.4.2 Ground Water Sampling and Analysis Requirements
The Agency is proposing requirements for ground water sampling and analysis at CKDLF
units similar to those established under 40 CFR 258.53 for MSWLFs. The proposed rule
allows the State to develop an alternative sampling procedure if necessary to protect human
health and the environment. For all CKDLF units, the owner or operator must develop a
sampling and analysis plan for monitoring releases to ground water. The State Director must
be notified that the sampling and analysis program documentation has been placed in the
operating record.
Ground water sampling and analysis procedures are designed to ensure consistency and obtain
accurate ground water quality data at (a) hydraulically-upgradient background wells, and (b)
downgradient wells at the point of compliance. As stated in the previous subsection,
downgradient monitoring wells must be designed and constructed to detect potentially
contaminated ground water from the CKDLF unit. For facilities located in karst terrain, EPA
is also proposing that a ground water monitoring strategy include, where necessary,
monitoring of springs which are the ultimate discharge points of the karst ground water basin
in which the facility is located. Additional information on the use of springs in a ground water
monitoring strategy is provided in Section 7.1. Records of the sampling and analysis program
shall include procedures and techniques used for sample collection; sample preservation and
shipment; analytical procedures; chain of custody control; and quality assurance and quality
control. The ground water monitoring program must include sampling and analytical methods
that are appropriate for ground water sampling and that accurately measure hazardous
constituents and other monitoring parameters in ground water samples. Ground water samples
shall not be field-filtered prior to laboratory analysis. Owners and operators of a CKDLF shall
be required to establish background concentrations in a hydraulically upgradient well or
background well(s), and if in karst terrain, in springs for each of the monitoring parameters or
constituents required in the ground water monitoring program. Ground water sampling
procedures and frequency must be protective of human health and the environment during the
active life, closure and post-closure periods of the CKD disposal site.
Ground water elevations must be measured in each well immediately prior to purging for each
ground water sample. In addition, the owner or operator must determine the rate and direction
of ground water flow each time ground water is sampled. Ground water elevations in wells
which monitor the same waste management area must be measured within a period of time
short enough to avoid temporal variations (e.g., pumping well effects and climatic conditions)
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in ground water flow which could preclude accurate determination of ground water flow rate
and direction.
The number of samples collected to establish ground water quality must be consistent with
the appropriate statistical procedures described in section 5.4.3.
5.4.3 Statistical Analysis of Ground Water Monitoring Data
The Agency is proposing performance standards and technical procedures for the statistical
analysis of ground water monitoring data at CKDLF units. The standards and procedures are
similar to those already established for ground water monitoring conducted under 40 CFR Part
258 (for MSWLF units) and 40 CFR Part 264 (for land-based hazardous waste management
units)3, however, the requirements can be tailored to address the characteristics of CKD and
provide sufficient flexibility to allow effective implementation by facilities and States.
The statistical analysis requirements will be applicable to all new and actively managed
CKDLF units. The use of statistical procedures to evaluate ground water monitoring data shall
be used for the duration of the monitoring program, including the post-closure care period.
The proposed requirements provide that the owner or operator of a CKDLF units must select
an appropriate statistical procedure to determine if samples taken from downgradient
monitoring wells represent a statistically significant increase over background values for each
parameter or constituent that occurs in the downgradient sample. The proposed rule requires
the owner or operator to employ one of four statistical procedures or an alternative procedure
that would protect human health and the environment and meet the proposed ground water
protection standard. The four statistical procedures proposed by EPA include:
1) A parametric analysis of variance (ANOVA) followed by multiple comparisons
procedures to identify statistically significant evidence of contamination,
2) An analysis of variance based on ranks followed by multiple comparisons
procedures to identify statistically significant evidence of contamination,
3) A tolerance or prediction interval procedure; and
4) A control chart approach.
The proposed rule also will allow the State to develop an alternative sampling procedure and
statistical test if necessary to protect human health and the environment. In establishing an
o
See 52 FR 31948 Statistical Methods for Evaluating Ground water Monitoring Data from Hazardous
Waste Facilities and 56 FR 50978 Solid Waste Disposal Criteria; Final Rule.
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alternative statistical method, the State should consider the performance standards for the
statistical analysis methods. The performance standards for the statistical analysis of ground
water monitoring data at CKDLFs are based on those already promulgated under 40 CFR Part
258.53(h) for MSWLFs. The performance standards include the following:
1) The method must be appropriate for the observed distribution of the data
2) Individual well comparisons to background ground water quality or a ground
water protection standard shall be done at a Type I error level of no less than
0.01 or, if the multiple comparisons procedure is used, the experiment-wise
error rate for each testing period shall be no less than 0.05
3) If a control chart is used, the type of chart and associated parameter values shall
be protective of human health and the environment
4) The level of confidence and percentage of the population contained in an
interval shall be protective of human health and the environment
5) The method must account for the data below the limit of detection (less than the
PQL) in a manner that is protective of human health and the environment
6) The method must account for seasonal and spatial variability and temporal
correlation of the data, if necessary.
The performance standards provide means to limit the possibility of making false conclusions
from the monitoring data.
5.4.4 Detection Monitoring
A detection monitoring program similar to that used under 40 CFR 258.54 is proposed for all
new and actively managed CKDLF units. The proposed rule allows the State to develop an
alternative monitoring program if necessary to protect human health and the environment.
Detection monitoring shall be implemented at all ground water monitoring wells and springs
included in the ground water monitoring system. The detection monitoring program must
include sampling for the indicator parameters identified in Table 5-2 to establish background.
These detection parameters have been proposed to the Agency by the cement industry as
constituents that are easily measured and provide a reliable indication of inorganic releases
from the CKD waste management unit to ground water (PCA, 1995).
Table 5-2. Indicator Parameters for Detection Monitoring
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Constituents/Parameters
Chloride
Potassium
Sodium
Sulfate
Conductivity
Total dissolved solids
Monitoring shall be conducted at least semi-annually during the active life, the closure and
post-closure periods of a CKDLF unit to determine whether there has been a statistically
significant increase over background. At least four independent samples from each well (or in
the case of downgradient locations, wells and springs) must be collected and analyzed for
constituents listed in Table 5-2 or an approved alternative list during the first semiannual
sampling event.
At least one sample must be collected from each well and spring (background and
downgradient) and analyzed during subsequent semiannual sampling events. The State
Director may specify an appropriate alternative frequency for repeated sampling and analysis
for Table 5-2 constituents, or an approved alternative list during the active life (including
closure) and post-closure care period.
When detection monitoring parameters are identified at statistically significant levels over
established background concentrations at any monitoring well or spring at the waste
management unit boundary, assessment monitoring must be initiated.
5.4.5 Assessment M onitoring
The EPA proposes that assessment monitoring be required at a CKDLF unit whenever a
statistically significant increase over background is detected for one or more of the constituents
listed in Table 5-2. The assessment monitoring program for CKDLFs is similar to the
assessment monitoring approach used under 40 CFR 258.55 for MSWLFs.
Owners and operators shall begin to sample and analyze for constituents listed in Table 5-3
(antimony, arsenic, barium, beryllium, cadmium, chromium (total), lead, mercury, nickel,
selenium, silver, thallium, and vanadium) within 90 days of the detection monitoring event
indicating the occurrence of a contaminant release. Subsequent assessment monitoring shall be
conducted semi-annually after the first round of assessment sampling is conducted. A
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minimum of one sample from each downgradient well and spring must be collected and
analyzed during each sampling event.
Table 5-3.Constituents and MCLs for Assessment Monitoring
Constituents/Parameters
MCL (mg/L)
Antimony
0.006
Arsenic
0.05
Barium
2.0
Beryllium
0.004
Cadmium
0.005
Chromium (total)
0.1
Lead
0.015
Mercury
0.002
Nickel
Remanded 6/95
Selenium
0.05
Silver*
0.1
Thallium
0.002
Vanadium
No MCL
Source: EPA Drinking Water Hotline (6/10/98)
* Secondary drinking water standard for silver shown. All other
MCLs shown are primary drinking water standards.
The constituents of concern identified in Table 5-3 are those constituents reasonably expected
to be in, or result from, CKD disposed in landfills or other land-based management units. In
addition, the constituents have been found at elevated concentrations in ground water in the
vicinity of CKD landfills as documented in EPA's damage case summaries (see Table 2-1 in
Chapter 2).
The Agency proposes a ground water protection standard for constituents of concern listed in
Table 5-3. As discussed in Section 5.2, the protection standard shall be the MCL, or the
background concentration of that parameter for the site. If the background level is higher than
the MCL for a constituent, the background level must be used as the ground water protection
standard.
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If one or more of the constituents listed in Table 5-3 are detected at statistically significant
levels above the ground water protection standard in any sampling event, the owner or
operator must:
• characterize the nature and extent of the release by installing additional
monitoring wells if necessary;
• install at least one additional monitoring well at the facility boundary in the
direction of contaminant migration and sample this well;
• notify all persons who own land or reside on land that directly overlies any part
of the plume of contamination if contaminants have migrated off-site; and
• initiate an assessment of corrective measures within 90 days.
5.4.6 Assessment of Corrective Measures
EPA is proposing requirements for an assessment of corrective measures similar to those
promulgated under 40 CFR 258.56 for MSWLFs. An assessment of corrective measures shall
begin within 90 days of detecting constituents at statistically significant levels above ground
water protection standards (Section 5.4.5). Such an assessment must be completed within a
reasonable period of time.
The owner/operator shall be required to continue to monitor in accordance with the monitoring
assessment program. The assessment of corrective measures shall include an analysis of the
effectiveness of potential corrective measures and address at least the following:
• the performance, reliability, ease of implementation, and potential impacts of
appropriate potential remedies, including safety impacts, cross-media impacts,
and control of exposure to any residual contamination;
• the time required to begin and complete the remedy;
• the costs of remedy implementation; and
• the institutional requirements such as State or local permit requirements or other
environmental or public health requirements that may substantially affect
implementation of the remedy (s).
Prior to selection of the remedy, the owner/operator must discuss the results of the corrective
measures assessment in a public meeting with interested and affected parties.
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5.4.7 Selection of a Remedy
After conducting the assessment of corrective action, the owner or operator shall select a
course of action that is similar to 40 CFR 258.57, and at a minimum,
• protects human health and the environment,
• achieves the ground water protection standard specified in Section 5.4.5,
• controls contaminant releases in order to reduce or prevent further releases
which may threaten human health or the environment, and
• enables compliance with any RCRA requirements to be achieved.
In addition, the owner or operator shall include with the specified remedy a schedule or
schedules for beginning and completing remedial activities.
5.4.8 Implementation of Corrective Action
Upon selecting the schedule of remedial activities, the owner or operator shall establish a
corrective action ground water monitoring program that shall at least:
• meet the requirements of an assessment monitoring program;
• indicate the effectiveness of the corrective action remedy; and
• demonstrate compliance with ground water protection standards specified in
Section 5.4.5.
The owner/operator also is required to implement the selected corrective action remedy and
take any interim measures necessary to ensure the protection of human health and the
environment. Interim measures should, to the greatest extent practicable, be consistent with
the objectives of and contribute to the performance of any remedy that may be required in
Section 5.4.7.
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References
Algermissen, S.T., et al., 1991. "Probabilistic Earthquake Acceleration and Velocity Maps for the
United States and Puerto Rico." USGS Miscellaneous Field Study Map MF-2120.
Algermissen, S.T., et al., 1976. "Probabilistic Estimates of Maximum Acceleration and Velocity
in Rock for the Contiguous United States." Open File Report 82-1033; USGS,
Washington, D.C.
Anderson, D.G. and E. Kavazanjian, Jr., 1995. "Performance of Landfills Under Seismic
Loading." Paper presented at the Third International Conference on Recent Advances in
Geotechnical Earthquake Engineering and Soil Dynamics, University of Missouri at Rolla,
April 2-7, 1995.
The MITRE Corporation (MITRE), 1980. Guidance Document, Seismic Considerations,
Hazardous Waste Management Facilities, Draft. McLean, Virginia. December 29, 1980.
Portland Cement Association, 1995. Cement Kiln Dust Management Practices. Draft Report.
16p.
RMT, Inc. (RTM), 1996. Remedial Investigation (Phase II) Report, Final, Volume I of II.
Prepared for Medusa Cement Company, Charlevoix, MI. Prepared by RTM, Ann
Arbor, MI. August 1996.
USEPA, 1997a. CKD Waste Releases and Environmental Effects Summary, Holnam
Incorporated, Mason City, Iowa. Draft document prepared by ICF under EPA Contract
68-W4-0030.
USEPA, 1997b. CKD Waste Releases and Environmental Effects Summary, Lehigh Portland
Cement Company, Mason City, Iowa. Draft document prepared by ICF under EPA
Contract W4-68-0030.
USEPA, 1997c. Detailed Summary of the CKD Disposal at Lehigh Portland Cement
Company, Metaline Falls, Washington. Prepared by SAIC under EPA Contract No.
68-W4-0030.
USEPA, 1997d. CKD Waste Release and Environmental Effects Summary: Portland Cement
Superfund Site, Salt Lake City, Utah. Prepared by SAIC under EPA Contract No.
68-W4-0030.
USEPA, 1997e. Technical Background Document - Additional Documented and Potential
Damages from the Management of Cement Kiln Dust. Office of Solid Waste.
September 3, 1997.
Draft: June 1998
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USEPA, 1993a. Report to Congress on Cement Kiln Dust. Volume II: Methods and
Findings. Office of Solid Waste.
USEPA, 1993b. Solid Waste Disposal Facility Criteria, 40 CFR Part 258, Technical Manual.
November 1993.
USGS, 1978. "Preliminary Young Fault Maps, Miscellaneous Field Investigation (MF) 916".
Draft: June 1998
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Chapter 6: Effectiveness of Proposed CKD Landfill Design Elements
Current baseline designs and practices at CKDLF units are inadequate to protect ground water
resources as evidenced by the damage cases discussed in Section 2.1.1. The Agency evaluated a
range of possible landfill design configurations and performance standards (see Chapter 3) and
generated upper bound estimates of the types of controls that might be required at new CKDLF
units in the U.S. and Puerto Rico (see Chapter 4). A summary of the proposed standards and
rationale to protect ground water resources at CKDLF units is provided Chapter 5. The
proposed standards are intended to improve upon baseline CKD landfill designs and practices. To
evaluate the expected performance of the proposed management standards, the Agency also
studied the performance of landfills that manage waste similar to CKD and evaluated the
effectiveness of CKD when used as a landfill liner or cap material. To evaluate the performance
of landfills managing waste similar to CKD, EPA analyzed information from several coal ash
landfills and CKD disposal sites. Besides the use of liners, coal ash landfills may install leachate
collection and ground water monitoring systems and pre-treat wastes before disposal to improve
ease of handling and obtain the consistency suitable for landfill disposal. A more detailed
evaluation of coal ash landfills can be found in a background report entitled Technical
Background Document on the Efficiency and Effectiveness of CKD Landfill Design Elements -
Draft Report (USEPA, 1997a).
Section 6.1 presents landfill design and operating information on coal ash disposal sites associated
with two coal-fired power plants in Pennsylvania. In Section 6.2, the performance of these
landfills with respect to preventing ground water contamination is compared with the proposed
CKD landfill standards. In Section 6.3, the performance of the ground water monitoring systems
at these landfills is compared with the proposed CKD landfill standards. Landfill performance
data were evaluated for these Pennsylvania coal ash landfills in a technical background document
prepared in support of EPA's CKD rule making efforts (USEPA, 1997a).
Several CKD disposal facilities have proposed or used conditioned CKD as a cover or bottom
liner material for a CKD landfill. The effectiveness of conditioned CKD as an engineered
component in a landfill design is evaluated in Section 6.4.
6.1 Coal Ash Disposal at Selected Landfills in Pennsylvania
This section draws on the operating and landfill performance data at coal utility plants for
disposing large quantities of fly ash to validate the proposed CKD disposal standards presented in
Section 5.2. Coal fly ash has many characteristics similar to CKD including a fine grain size, and
elevated concentrations of certain toxic metals including arsenic, chromium and lead. TCLP
analysis of 12 fly ash and 13 bottom ash samples found no results above the RCRA toxicity limits.
Extraction Procedure (EP) analyses found that 2 out of 78 fly ash samples exceeded the RCRA
toxicity limits for arsenic or chromium (by a factor of 3.3 or 1.7, respectively) (USEPA, 1993a).
CKD and coal combustion wastes are generally alkaline and have very low concentrations of
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organic compounds. pH values for CKD leachate range from 6.11 to 12.98 standard units
(USEPA, 1993b), and a study of ash derived from bituminous, sub-bituminous, and lignite coals
reports pH values of 8.2, 10.8 and 9.2 standard units, respectively (Adriano, et al., 1980).
Coal combustion wastes may be managed in impoundments, landfills, mines and quarries or other
facilities. Approximately 45 percent of all the coal ash disposal units in the United States are
landfills. Old utility ash landfills and surface impoundments are generally simple, unlined systems.
After 1975, over 40 percent of all generating units managed their wastes in lined facilities using
one or more layers of low permeability clays or synthetic liners, or a combination of both. Fly ash
has been incorporated in some clay liners since it is cohesive and fairly impermeable when
properly compacted. However, variabilities in its chemical composition and changes in its
permeability and shear strength over time limit its use (USEPA, 1988). Flue gas desulfurization
(FGD) waste from air pollution abatement equipment (i.e., scrubbers) is often co-disposed with
fly ash. FGD waste consists of primarily of calcium sulfate (i.e., gypsum) which dissolves in
water and has no shear strength under high moisture conditions. FGD waste is not disposed at
the Montour and Titus/Beagle Club ash landfills.
6.1.1 Montour Generating Station/Ash Storage Sites 2 and 3
The Montour Steam Electric Station, owned by the Pennsylvania Power & Light Company
(PP&LC), is located on the Chillisquaque Creek in Derry Township, Montour County,
Pennsylvania. It first started producing electricity in 1972 and currently has an electric generating
capacity of 1500 MW. Montour has two coal ash disposal landfills with a bottom liner design
similar to that required under Subtitle D for municipal landfills including a low permeability
bottom layer (geomembrane or clay <10"7 cm/s permeability) with leachate collection, and 1 or 2
ft thick compacted bottom ash drainage blanket with perforated pipe for leachate collection. Both
landfills have an underdrain below the landfill bottom liner to prevent upgradient surface run-off
and ground water from flowing into the landfill.
Operations in Ash Storage Area 2 began in 1982 and lasted until 1989 when ash disposal activities
began in Ash Storage Area 3. In 1982, fly ash waste management practices changed from sluicing
to Ash Basin 1 to pneumatically transporting fly ash to silos for temporary storage. The fly ash is
then conditioned with water and either sold off-site for beneficial uses or disposed of on site.
Montour is able to sell most of the fly and bottom ash that is generated, primarily as light weight
construction fill. Ash Storage Area 2 is permitted to cover 34 acres and is lined either with 20-mil
PVC (where depth to ground water is less than 2 feet) or with two feet of clay soil with a
maximum permeability of 10"7 cm/s. Ash Storage Area 3 is permitted to cover 64 acres and is
underlain by a 30-mil PVC bottom liner.
The conditioned fly ash is compacted to a minimum of 90 percent of Standard Proctor (ASTM,
D698) maximum density with a smooth wheel vibratory roller during disposal. Fly ash surfaces
that are completed but not at final grade are sprayed with water or a dust control agent or
covered with bottom ash if the ash surface begins to dust (PP&LC, 1981). Permit conditions
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require a one-foot thick final clay cover for Ash Storage Area 2 and a two-foot thick final clay
cover for Ash Storage Area 3. Storm water run-off and landfill leachate is collected in surge
ponds adjacent to the landfills, routed to the plant's Miscellaneous Plant Waste Basin for
treatment with other plant waste waters and discharged under a NPDES permit. Ground water
monitoring has identified some evidence of downgradient contamination due to oxidation of
naturally occurring pyrite in the bedrock shale formation. Recent repairs made to Area 3 surge
basin overflow spillway may have caused elevated levels of sulfate, calcium, and specific
conductivity in downgradient monitoring well MW-3-3 relative to pre-1996 monitoring results
(PP&LC, 1997).
6.1.2 Titus Generating Station/Beagle Club Ash Disposal Site
The Titus Generating Station is a steam electric generating plant located on the Schuylkill River in
Cumru Township, Berks County, Pennsylvania. It began producing energy in 1951, has a
generating capacity of 240 MW, and is operated by Metropolitan Edison Company (Met-Ed)/
GPU Genco. The Beagle Club Ash Disposal Site is located about 1 mile south of the City of
Reading, adjacent to Highway 422, and immediately across the Schuylkill River from the Titus
Generating Station. Disposal operations at the Beagle Club Ash Disposal Site began when it was
permitted as a new ash disposal site in 1978. Major permit modifications were issued to the
facility in 1984 to construct a leachate collection system under the landfill and to install
leachate/run-off treatment ponds and in 1991 to install a 50-mil PVC bottom liner under new
portions of the facility. Because the 1984 permit prohibited new ash disposal over the old ash fill
with out leachate collection, the pre-1984 ash landfill was excavated, stockpiled and then
reburied. A leachate collection system was installed under the entire landfill. A minimum 2-foot-
thick native clay layer is present under 9 acres of the landfill associated with pre-1991 ash
disposal. Since 1991, a 50-mil-thick PVC bottom liner has been used for the remaining 10.7 acres
of this landfill. An additional 18 acres has been permitted to provide support for the disposal area
including leachate/run-off pond system, soil stockpiles and access roads (CEC, 1992).
The fly ash generated at the station is collected in hoppers, conditioned with water, trucked to the
disposal site, spread in one foot lifts and compacted. Sludge from an ash sedimentation pond
associated with the fly ash loading area and bottom ash is periodically removed and disposed at
the disposal facility. Fly ash surfaces that are completed but not at final grade are sprayed with
water or covered with bottom ash if the ash surface begins to dust. Portions of the landfill, which
have been built up to the final grade, have been capped with a one-foot-thick clay layer (maximum
permeability is 10"7 cm/s) (Gilbert/Commonwealth, 1994). Landfill leachate and dirty storm run-
off are collected in ponds adjacent to the landfill and discharged under a NPDES permit to the
Schuylkill River. Based on analytical results to date, no treatment has been required for this
water.
Ground water degradation (i.e., sulfate and total dissolved solids (TDS) concentrations above
secondary drinking water limits in downgradient wells but not in background wells) due to coal
ash disposal has been observed at the Titus landfill. The leakage rate estimated by HELP model
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analysis for the 9 acre unlined portion of the landfill ranged from a maximum monthly flow rate of
1.6 gpm (0.3 inches/month) in 1994 to less than 0.1 gpm (0.02 inches/month) following site
closure, projected in 2008 (Gilbert/Commonwealth, 1994).
6.2 Comparison of Coal Ash Landfill Performance with Proposed CKD Landfill
Standards
This section summarizes the effectiveness of the landfills described in Sections 6.1.1 and 6.1.2 in
protecting ground water resources and projects how effective these design elements would
function at CKD landfills. Annual rainfall at both the Montour and Titus/Beagle Club locations is
about 40 inches (Sterner, 1994). Therefore, based on EPA's modeling and evaluation of CKD
landfill designs summarized in Section 4.4, the Subtitle D technical default standard would be
expected to perform acceptably, but the "Modified CKD High" and "Modified CKD Low" design
would not perform as well.
6.2.1 Composite Bottom Liner
Of the three landfills, only the Montour Ash Storage Area 3 used a modified composite bottom
liner design where the landfill is entirely underlain by a plastic (e.g., PVC) bottom liner.
However, the requirements for the clay portion of the composite liner for these landfills was less
stringent than the 2 feet of clay with a permeability less than 10"7 cm/s, specified in the RCRA
Subtitle D regulations (40 CFR 258.40(a)(2)). No minimum permeability (other than that
resulting from site clearing, grubbing and rolling soil flat) was required for the subbase material of
the Montour landfill. An underdrain was constructed at the Montour Area 3 landfill to drain
upgradient surface water and/or shallow ground water and to prevent excessive pressure heads
under the landfill. A leachate collection system consisting of bottom ash and perforated PVC
pipes was installed throughout the landfill immediately overlying the bottom liner.
Ground water monitoring results at the Montour facility indicate the presence of pre-existing,
poor quality ground water under these landfills. As discussed in Section 6.1.1, this pre-existing,
poor quality ground water makes it difficult to evaluate the potential for leakage through the
landfill bottom liners.
EPA is considering using the RCRA Subtitle D composite liner design as the technical default
standard for CKD landfills. EPA's evaluation of the Subtitle D composite liner design indicates
that the expected leakage from this design is very small and would be protective of human health
and ground water resources (see Section 4.4). In designing a bottom liner for CKD landfills in
non-karstic areas, EPA is considering a performance-based design standard that is based on the
RCRA Subtitle D performance standard found in 40 CFR 258.40(a)(1). This standard would
allow the use of a modified bottom liner design, such as those found at the coal ash landfill sites,
as long as there is no exceedance of EPA's maximum contaminant levels (MCLs) for drinking
water (or background, for constituent for which no MCL has been established) for arsenic,
antimony, barium, beryllium, cadmium, chromium, lead, mercury, nickel, selenium, silver, and
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thallium in the uppermost aquifer at the relevant point of compliance (POC).
6.2.2 Alternative Bottom Liner Designs
Portions of the Montour Area 2 and Titus/Beagle Club landfills do not have a plastic bottom liner,
but instead use compacted native clay as a bottom liner. At the Montour Area 2 facility, a plastic
liner was only used in areas where the depth to water was less than 0.6 meters (2 feet), otherwise
the bottom liner consisted of a 2-foot-thick native clay with a maximum permeability of 10"7 cm/s
(PP&LC, 1981). A 2-foot-thick native clay with no permeability requirement was used a bottom
liner for the Titus/Beagle Club landfill prior to 1991. From 1978 to 1984, the Titus/Beagle Club
landfill operated without a leachate collection system. In 1984 and 1985 this landfill was
excavated and stockpiled until redisposed on site in a landfill with a leachate collection system.
After 1991, a PVC bottom liner was installed at the Titus/Beagle Club landfill
(Gilbert/Commonwealth, 1994).
Ground water degradation downgradient of the Montour Area 2 and Titus/Beagle Club facilities
has been identified from the ground water monitoring data. Evaluation of trace element
concentrations in downgradient ground water at the Montour Area 2 facility indicates that no
leakage has been confirmed because the degradation appears to be related to oxidation of
naturally-occurring pyrite in the shale bedrock rather than fly ash constituents (PP&LC, 1987).
HELP modeling of the Titus landfill has predicted a current maximum leakage rate of 1.6 gpm
(0.3 inches/month) from the 9 acre portion of the landfill without a plastic liner
(Gilbert/Commonwealth, 1994). Higher landfill leakage rates and ground water degradation
probably occurred prior to 1984 when no leachate collection was performed. Based on these
observations, it appears that alternative bottom liner designs, such as that at Montour Area 2,
which do not use synthetic liners may be appropriate for some CKD landfills depending upon site-
specific conditions.
6.2.3 Compaction of Fly Ash Waste
Measures were taken at the Montour and Titus/Beagle Club power plants to condition the fly ash
with water and to compact it during disposal. This appears to have provided greater control over
fugitive dust emissions as well as extending the capacity of these landfills. Hoppers or silos also
were used at all of the utility plants to temporarily store the fly ash as it was being generated and
until it was transported to the landfill for disposal.
These dust control measures could be effectively applied at CKD disposal sites. Care must be
taken to not over apply water to CKD due to the potential caustic quality of the run-off that may
be generated and because this may result in failure to achieve the desired in-place density during
compaction. Conditioning CKD with water and compacting it during disposal is expected to help
control fugitive dust emissions and releases of CKD constituents to ground water. Conditioned
and compacted CKD has a higher density, higher strength, and lower permeability than
unconditioned CKD. Landfilling of conditioned and compacted CKD is expected to result in the
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production of less leachate and a more structurally stable landfill design relative to landfilling of
unconditioned CKD.
6.2.4 Landfill Closure and Post-Closure Measures
The Montour Area 2 facility was closed in 1989. Closure activities consisted of completing
installation of a final 1-foot-thick clay cover over the landfill, allowing it to become vegetated, and
continuing with the ground water monitoring program during a 30-year post-closure period.
Pennsylvania Department of Environmental Protection (PDEP) granted a variance for the 1-foot-
thick clay cover based on the results from demonstration plot tests of 1-foot-thick and 2-foot-
thick clay covers performed at the Montour site. A recent inspection of the Montour Area 2
landfill has found that erosion has exposed waste ash in one corner of the landfill where
vegetation did not become sufficiently established. PDEP staff attributes the poorer than
expected performance of the final cover to unfavorable growing conditions (i.e., soil removed by
erosion, lack of moisture, and excessive wind) at this exposed location. The performance of
vegetation growth in a relatively small test plot, however, may not be directly extrapolated for a
large landfill (Stevens, 1997).
EPA is considering standards for landfill closure and post-closure requirements based on the
RCRA Subtitle D regulations (40 CFR 258.60-61). The cover must have a permeability less than
or equal to the bottom liner or natural subsoils or have a permeability no greater than 10"5 cm/sec,
whichever is less. The cover must minimize infiltration by using an infiltration layer that contains
at least 18 inches of earthen material. The cover must minimize erosion by using an erosion layer
that contains at least 6 inches of earthen material that is capable of sustaining native plant growth.
Similar to the PDEP approach (Section 288.234 of the Pennsylvania Residual Waste Regulations),
an alternative landfill final cover design may be approved as long as it provides an equivalent
degree of infiltration and erosion protection.
6.3 Comparison of Coal Ash Landfill Performance with Proposed CKD Landfill
Ground Water Monitoring Requirements
This section evaluates the effectiveness of the ground water monitoring programs which were
implemented for the landfills described in Sections 6.1.1 and 6.1.2 with respect to identifying
potential releases of contaminants to ground water. The expected benefits of similar ground
water monitoring programs at CKD landfills is addressed in Section 6.3.2.
6.3.1 Ground Water Monitoring Design and Performance
A network of upgradient and downgradient monitoring wells/points are being monitored on a
quarterly basis at the Montour and Titus/Beagle Club coal ash landfills. At the Titus/Beagle Club
site, downgradient monitoring wells, located less than 90 meters (300 feet) from the landfill, have
provided timely warning that the ground water system has been impacted from ash disposal
operations. None of these landfills are located over karst aquifers. For CKD landfills at karstic
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sites, EPA is proposing a greater degree of site characterization and more sophisticated ground
water monitoring than those used for the studied coal ash landfills.
Potential ground water degradation downgradient of the Montour Ash Storage Area 2 was
identified within one year following commencement of ash disposal activities in 1981. A site
investigation was conducted with trace element analysis of the ground water near the landfill.
The site investigation report attributed the elevated concentrations in the downgradient wells to
oxidation of pyrite in the native bedrock materials and not from waste leachate. According to the
report, earthwork activities during construction of the landfill accelerated the rate of pyrite
oxidation in native materials resulting in increased concentrations of sulfate and TDS. Elevated
concentrations of indicator trace elements such as lithium, selenium, chromium and boron
associated with the fly ash waste were not detected in the ground water monitoring wells
(PP&LC, 1987). PDEP is currently evaluating the Montour Ash Disposal Area 3 ground water
monitoring results as part of the site's permit renewal effort. It is unclear if the circa-1996 rise in
sulfate and other constituents in downgradient wells is due to landfill leakage or recent
leachate/run-off pond repair work. The site operator suspects that the earth work associated with
repair of the leachate/run-off pond affected the water quality in the nearby monitoring wells
(Hamilton, 1997).
At the Titus/Beagle Club site, the operator/owner used a statistical method with a 99 percent
confidence level to evaluate ground water monitoring data and identified several constituents
including sulfate and TDS in downgradient wells at concentrations exceeding background (CEC,
1992). The statistical analysis of the ground water data indicates that waste disposal operations at
the site have impacted the ground water quality. As discussed in Chapter 5.2.3, EPA is proposing
statistical techniques similar to those in 40 CFR 258.53(g) and 40 CFR 264.97 to evaluate ground
water monitoring data at CKD landfills. The regulations include statistical methods similar to
those used for the Titus/Beagle Club ground water assessment.
6.3.2 Benefits of Ground Water Monitoring
Based on the evaluations of the CKD damage cases identified in Section 2.1.1, the Agency has
determined that additional controls, including ground water monitoring, are warranted to identify
and prevent potential releases of hazardous constituents from CKD landfills into ground water. A
ground water monitoring program, when correctly designed and implemented, determines
whether a waste management system effectively prevents contaminant releases to ground water;
detects releases quickly, avoiding costly contamination and cleanup; provides data to accurately
determine the nature and extent of any contamination that occurs; and can assess the effectiveness
of corrective actions. In the case of the Titus/Beagle Club coal ash landfill discussed in Section
6.3.1, the ground water monitoring system allowed early detection of a release. At CKDLF units,
semiannual ground water monitoring is expected to facilitate the timely evaluation and
remediation of potential releases of CKD contaminants to ground water systems.
Current and past CKD disposal practices have resulted in a number of cases where CKD
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constituents have contaminated ground water at CKD disposal sites. In response, EPA is
proposing a new set of performance standards and default technical design standards for new and
actively managed CKD landfills. The Agency believes that the proposed standards will provide a
number of benefits including increased protection of ground water resources and reduced risks to
human health. The proposed standards require CKD landfills to meet specific performance
standards which are protective of human health and the environment. EPA believes that
implementation of the proposed ground water monitoring standards that were described in
Section 5.2.3, coupled with the proposed design standards at new CKD disposal sites, will ensure
that future impacts on ground water resources will be minimized and future costs associated with
cleaning up contaminated sites can be avoided.
6.4 Effectiveness of the Use of CKD as a Landfill Liner or Cover
The use of CKD as engineered components of CKD landfills has been proposed by representatives
of the cement industry. At some existing or proposed CKD disposal sites, compacted CKD has
been proposed or used as a liner or capping material. As part of development of the proposed
regulations for CKD, EPA conducted a review of information on the physical properties of CKD,
identified the performance characteristics necessary for the use of CKD as liners or caps in CKD
landfills and reviewed specific cases where CKD has either been proposed or used as liners or
caps at existing or proposed CKD disposal facilities.
The results of the analysis indicate that very low hydraulic conductivities (less than 1 x 10"7
cm/sec) are readily achievable in the laboratory and in field trials using heavy equipment to
compress CKD to high densities. However, evaluation of field data indicate that compaction
control is difficult to maintain over an area that is acres in size. Nevertheless, EPA is not
proposing a prohibition on the use of CKD as a liner or cap material: EPA will allow its use as
part of an alternative unit design if the facility can demonstrate that the design meets the
performance standard for ground water, including establishing that the material will maintain
integrity over long periods of time and, therefore, has a low potential for release of contaminants.
This section describes EPA's findings on the effectiveness and efficiency of CKD proposed or
used as liners or caps at CKD landfills. Section 6.4.1 summarizes the findings of EPA's review of
the engineering properties of CKD from published sources and from information in the records of
selected CKD disposal locations where CKD has been proposed or used as engineered
components of landfills. Sections 6.4.2 and 6.4.3 provide summaries of circumstances where
CKD was proposed or used, respectively, for liners or caps at CKD disposal facilities. Section
6.4.4 compares the performance of conditioned CKD as a liner or cap material with respect to the
RCRA hazardous waste (Subtitle C) and solid waste (Subtitle D) regulations. Section 6.4.5
addresses the use of CKD and selected CKD-based materials as a daily or intermediate landfill
cover. Estimated costs associated with using CKD as a landfill liner and a cover material are
discussed in Section 6.4.6. Section 6.4.7 summarizes the findings from available field data on
CKD liners and covers.
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6.4.1 Engineering Properties of CKD and CKD-Based Liners and Caps
Sources of information on engineering properties of CKD identified include the references cited in
the Report to Congress on Cement Kiln Dust (USEPA, 1993b), reports and publications
identified subsequent to the Report to Congress and engineering design and construction
information available from CKD disposal sites in New York, Michigan and Washington.
The primary measure of performance for any landfill liner or capping material is its ability to serve
as a barrier to the movement of liquid vertically under the influence of gravity and hydraulic
forces. For liners at the bottom of a landfill the liquid includes water from precipitation and
dissolved constituents from the waste (leachate). For caps, the liquid is the precipitation that
infiltrates to the capping barrier layer. The degree to which a liner or cap limits the movement of
liquid is generally measured by its hydraulic conductivity or permeability.
For synthetic membranes used as liners or caps, the degree to which the movement of liquid
occurs generally depends on molecular diffusion through the membrane material, to a limited
extent, and to a much more significant extent, on imperfections ("pin holes") that may be present
in the supplied material, the degree to which holes or tears may occur during installation or in the
longer term and the success in sealing the seams in the material as it is placed (USEPA, 1993c).
For soil and soil-like materials that are used as liners or caps the permeability is measured in terms
of Darcy's law, Q = KAI, where Q = the rate of flow through a given cross sectional area of the
material, A, under a specific hydraulic gradient, I, and K is the coefficient of permeability,
typically measured in cm/sec. As described above, clay liners used in conjunction with synthetic
liners in RCRA Subtitle D municipal solid waste landfills (MSWLF) and hazardous waste landfills
are required to show a coefficient of permeability, K, of 1 x 10"7 cm/sec or less. For comparison,
poorly graded sand has a saturated permeability of about 1.0 x 10"2 cm/sec (USEPA, 1994). An
extensive discussion of soil liners, tests for permeability and other physical characteristics and
compaction of soil liners is presented in EPA's Technical Manual for Compliance with 40 CFR
Part 258 in the design and construction of MSWLFs (USEPA, 1993c).
6.4.1.1 Overview - Physical Properties and Testing - Soils
The following sections describe the physical properties and tests used in the engineering
evaluation of soil and soil-like materials that are also used in the engineering evaluation of CKD.
Soil Texture and Particle Size Distrihution
Several classification systems are in use to characterize soils in terms of particle size and particle
size distribution. Two classification systems widely used are the U.S. Department of
Agriculture's system and the Unified Soil Classification System.1 In the Unified System (ASTM
1 The Engineering Documentation for Version 3 of the Hydrologic Evaluation of Landfill Performance
(HELP) Model provides a comparison of the two classification systems in terms of typical soil characteristics (EPA,
Draft: June 1998
6-9
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D2487), soils are classified into three major groups: coarse grains, fine grains, and highly organic.
Coarse grained particles are those larger than a No. 200 sieve (.075 mm or 75 //m), with gravel
classed as particles smaller than 3 inches but larger than a No. 4 sieve (3/16-inch or 4.75 mm) and
sand classified as particles smaller than a No. 4 sieve, but larger than a No. 200 sieve. Fine grains
are smaller than a No. 200 sieve and include silts and clays.
The amounts of the various sizes of grains in a soil can be determined by sieving, for the more
coarse grains and by sedimentation (ASTM D422), or other means for the fine material. In a well
graded soil, there is a good representation of all particle sizes from the largest to the smallest.
Poorly graded soils are considered uniform when most of the particles are the same size or skip or
gap graded when there is an absence of one or more intermediate sizes (USBR, 1977).
The terms well sorted and poorly sorted are also frequently used when describing the particle size
distribution of soil samples. Size sorting refers to the degree to which the soil particles approach
being the same size (Compton, 1973). In a well sorted soil, most of the soil particles are about
the same size. In a poorly sorted soil, a wide range of soil particle sizes are present.2
Particle size distribution tests conducted on samples of CKD from three different types of cement
kiln processes showed in excess of 90 percent of the CKD particles smaller than the No. 200 sieve
size (75//m) (Todres, et al., 1992). Applying the Unified Soil Classification System definitions to
CKD, CKD would be classified as a silt or clay based on particle size. Particles in this size range
are not amenable to sieve analysis. Particle size distributions for small particles may be
determined by hydrometer (ASTM D422) or by methods such as the Sedigraph cited by Todres et
al., which uses x-ray intensity to determine the settling rate of particles in a liquid for subsequent
correlation with the associated particle size distribution.
Particle size distribution and particle size has relevance to the density and permeability and other
engineering properties of soils. For granular soils, the greater the range of particle sizes present,
the greater the maximum density (e.g., in poorly sorted soil, the voids among larger particles can
be filled with smaller particles) (Lamb and Whitman, 1969). In the CKD tests conducted by
Todres et al., particle size distribution analyses of three types of dusts (from a long wet rotary
kiln, a long dry rotary kiln, and from an alkali bypass, precalciner system) showed the particle
sizes of dust from the long wet kiln to be poorly sorted while the dusts from the other sources
were well sorted. The results of the maximum density tests showed the long wet kiln dust
achieving a higher maximum density than the other dusts (Todres, et al., 1992). Density testing is
described below. The size of the particles present also has relevance to potential for emissions of
fugitive dust, which is being addressed in other EPA documents.
1994). Hereinafter, descriptions of soils and soil-like materials refer to the Unified Soil Classification System.
2 The terms "graded" and "sorted" are in common usage in engineering and geological practices,
respectively. A well graded soil using engineering definitions would be described as poorly sorted using geological
practice definitions.
Draft: June 1998
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Density. Porosity, and Compaction Testing
Soil density is the weight per unit volume of the soil including any water present, expressed in
grams per cubic centimeter (g/cm3), kilogram per cubic meter (kg/m3) or pounds per cubic foot
(pcf).3 The in-situ density of a soil will depend on the specific gravity of the soil particles present,
the volume of pore space (void space) in the soil matrix, and the degree to which the pore space is
saturated with water. Samples of in-situ soil may be taken to determine undisturbed density using
a thin wall push tube with subsequent recording of the weight of the soils and, if required, the
weight and volume relationships, including a determination of moisture content (see ASTM
D2937). The use of thin wall tubes to obtain CKD samples for permeability testing is noted in a
number of the references discussed in Section 6.3. The use of the sand cone density test has also
been referenced (ASTM D1556).
The use of a nuclear source in measurement of in-place density and moisture content of field
compacted CKD has also been reported in several of the references. In this method, the
attenuation or scattering of radiation is recorded and correlated to density and moisture content
values determined by conventional means to provide a rapid means for determining if desired
density and compaction is achieved in the field (see ASTM D2922 and ASTM D3017).
Porosity is the volume of void space in a unit volume divided by the total volume, normally given
as a percent. Void ratio is the volume of void space divided by the volume of the solid soil
particles in the soil matrix, also given as a percent. The porosity or void ratio of a soil is of
significance to the consideration of soil permeability because as a soil is compressed (compacted),
the volume of the voids decrease and the permeability of the soil decreases (Terzaghi and Peck,
1967).
The properties of soil may be significantly altered by compaction and standard tests are available
to establish the relationships between density, water content, and compactive effort. The standard
Proctor test (ASTM D698) and Modified Proctor test (ASTM D1557) are widely used to
determine these relationships. In these tests, samples of soils are placed in standard size
containers and subjected to compaction using standardized means. The water content (moisture
content) of soil samples are varied and resulting densities (unit weights) are plotted to determine
the moisture content at which density is maximized. The resulting maximum density is referred to
as maximum dry density (MDD) and the moisture content at which MDD occurs is referred to as
the optimum moisture content (OMC) (Todres, et al., 1992).
Often, densities of at least 95 percent of the maximum dry density determined from Proctor tests
are specified in the construction of compacted fills (Merritt, 1976). In the data reviewed on
compaction of CKD, 95 percent of Proctor maximum dry density (or "95 percent Proctor") is
frequently specified.
3 The term "density" is commonly used in engineering practice, but the actual resulting value is "unit
weight". In the historical information reviewed concerning engineering properties of CKD, the density of CKD
(e.g., the unit weight) is provided in the pcf units.
Draft: June 1998
6-11
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Permeability Testing
The significance and importance of a liner and cap permeability in landfill performance is
described in the foregoing sections of this document. Prior to construction of liners or caps using
soils or soil-like materials such as CKD, the relationship between water content, density and
permeability may be established in the laboratory. For compacted clay soil the lowest
permeability is achieved when the soil is compacted at a moisture content slightly greater than
optimum (USEPA, 1993 c).
Ideally, placement of the liner or cap material in the field could be accomplished at the moisture
content and degree of compaction that laboratory results show would result in the lowest
permeability. However, EPA reports that differences between laboratory and field conditions
(e.g., uniformity of material, control of water content, compactive effort, compaction equipment)
make it unlikely that minimum permeability values measured in the laboratory on pre-construction
samples are the same values that will be achieved during actual soil liner construction (USEPA,
1993c).
Several types of apparatuses are available for laboratory determination of permeability of soils and
soil-like materials. In the information reviewed on CKD permeability tests, the use of a flexible
wall permeameter (ASTM Method D5084-90) is most frequently referenced. Push-tube or core
samples from the field may be taken for laboratory analysis or in-field tests using an infiltrometer
may be conducted to verify and compare the results of pre-construction values predicted by
laboratory tests to tests of the materials as placed.
EPA has identified four types of permeability tests for application in-situ including: borehole tests;
porous probes; infiltrometer tests, and underdrain tests (USEPA, 1993c). An infiltrometer testing
procedure used during closure of a the Lehigh Cementon CKD landfill in New York is described
in subsequent sections of this document.
Compaction in the Field and Test Pads
As described above, tests to determine maximum dry density (e.g., the Proctor Test) of soil and
soil-like materials are conducted under standardized conditions where the compactive effort is
controlled. In the Proctor test or Modified Proctor test the compactive effort is determined by the
energy transferred to successive layers of material in a mold via a tamping rod of specified weight,
dropping from a specified height a specified number of times.
Placement of a soil or soil-like lining such as clay or CKD under field conditions requires the use
of heavy equipment to achieve the degree of compaction specified based on the laboratory
compaction tests. The method used to compact the soil liner is an important factor in achieving
the required minimum permeability. Higher degrees of compactive effort increase soil density and
lowers the permeability for a given moisture content of the soil being placed (USEPA, 1993c).
In the construction of a soil liner field compaction unit, a sheepsfoot roller is frequently used
(USEPA, 1993c). Other field compaction equipment units include rubber tire rollers, smooth
Draft: June 1998
6-12
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wheel rollers, crawler tractors, vibratory compactors and power tampers (USEPA, 1980).
At the Ash Grove Cement Plant in Chanute, Kansas, field studies using test pads were conducted
to assess the compaction and permeability of CKD using various compaction techniques.
Equipment used in these tests included a vibratory padfoot roller, a rubber tire roller and a
vibratory drum roller (Todres, 1992). Studies of CKD compaction and permeability using a
rubber tire scraper and a vibratory drum roller were recently conducted on test pads located at the
Medusa Portland Cement Company facilities in Charlevoix, Michigan (RMT, 1996a). The results
of these tests are summarized in Section 6.3.
Other Testing Procedures
There are a number of other testing procedures used in designs of foundations, designs of structures
supported by soil or designs using soils as structural elements. These include, but are not limited to:
• Atterberg Limits - These tests are conducted on fine grained cohesive soils and determine
water content at the boundary between liquid, plastic, semisolid and solid states of the soil
matrix (see ASTM D4318).
• Confined Compression Tests - These tests are conducted to obtain information on the
volume change in soils subject to vertical loading when lateral deformation is restricted.
• Direct and Triaxial Shear Tests - These tests measure the strength of the soil in resisting
stresses.
Data available on the physical properties of CKD are summarized in the following section.
6.4.1.2 Engineering Properties of CKD
Permeability
Table 6-1 summarizes the test data on the permeability of CKD that were reviewed to assess the
effectiveness of CKD as a liner or cap material at CKD landfills. The source of the information
reported is provided along with notations, as appropriate, on the circumstances of the testing and
related explanatory information.
As shown in Table 6-1, a wide range of permeability values have been reported for CKD. The
only in-field permeability data found were developed during the closure of the Lehigh Cementon
CKD landfill in Green County, New York, in 1988 (see entry No. 2 in Table 6-1). As described
in further detail in Section 6.4.2.1.1, a falling head field testing procedure, approved by the New
York State Department of Environmental conservation, was used. CKD permeability ranged from
7.9 x 10"7 to 2.5 x 10"5 cm/sec, with a median value of 3.2 x 10"6 cm/sec for the fifteen (15) tests.
In the other test results summarized in Table 6-1, permeability tests were performed in the
laboratory, in many cases on remolded samples taken from the field in Shelby tubes. Where
Draft: June 1998
6-13
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testing on remolded samples was conducted, the results do not necessarily reflect actual, in-place
permeability.
As discussed in more detail in Section 6.4.2.1.2, difficulties in retrieving undisturbed samples were
reported. In the closure of the Lehigh Alsen CKD landfill, the results of 24 tests were reported.
(See entry No. 4 in Table 6-1). Of these 24 tests, nine (9) were reported as undisturbed. These
nine (9) tests showed a range of permeability from 2.9 x 10"6 to 1.6 x 10"4 cm/sec, with a median
value of 5.1 x 10"5 cm/sec, which is similar to the range and median reported for all samples taken
during closure of the Alsen facility.
The tests reported by Todres et al. (1992) on three different cement dusts, at three different
compaction rates show the variations that may occur when compaction changes and the variability
among dusts. (See entry Nos. 11, 12, and 13 in Table 6-1). In these tests, the influence of
compaction on permeability is readily seen. With light compaction (to a density of 86.5 pounds
per cubic foot (pcf)), dust sample "G" from a long wet kiln showed a permeability of 1.5 x 10"3
cm/sec; with medium compaction (to 93.7 pcf) this dust showed a permeability of 7.6 x 10"6
cm/sec; with heavy compaction (to 108.2 pcf) this dust showed a permeability of 1 x 10"10 cm/sec.
The most extensive array of verification test information for CKD actually placed in the field is
provided in entry No. 6 in Table 6-1. During closure of portions of the Independent Cement
Corporation CKD landfill in Greene County, New York, fifty-eight (58) permeability tests were
conducted for CKD placed and compacted in the field. As shown in Table 6-1 and described in
more detail in Section 6.4.2.2, the median value for permeability of these samples was 2.1 x 10"5
cm/sec. Additional discussion of permeability of CKD is provided in Sections 6.4.2 and 6.4.3.
Draft: June 1998
6-14
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Table 6-1 Summary of CKD Permeability Test Data (Permeability Reported in cm/sec)
Entry
No.
No. Of
Tests
Minimum
Maximum
Average
Median
Test
Location
Test
Procedure
CKD Type
Comments
Reference
1
3
6.7 x 10"9
3.2 x 10"8
2.2 x 10"8
2.7 x 10"8
Laboratory
Flexible Wall
Permeameter
Fresh
Sample with lowest
value compacted at
optimum moisture
CHA 1986a.
Lehigh, Cementon
(Design Phase)
2
15
7.9 x 10"7
2.5 x 10"5
6.0 x 10"6
3.2 x 10"6
Field
Infiltrometer on
test panel
constructed
during site
closure
Field
compacted with
sheepsfoot and
steel drum
rollers
Field testing
approved by New
York State
Department of
Environmental
Conservation
CHA 1989. Lehigh,
Cementon (Construction
Phase)
3
9
7.7 x 10"7
7.0 x 10"5
1.3 x 10"5
1.6 x 10"6
Laboratory
Flexible wall
permeameter
Fresh,
weathered or
test pad
Minimum value was
fresh. CKD
maximum value was
from test pad.
Dunn, 1992a. Lehigh,
Alsen (Design Phase)
4
24
2.7 x 10"6
1.6 x 10"4
6.8 x 10"5
5 x 10"5
Laboratory
Field
compacted
See Section 6.4.2. of
text. Undisturbed
samples show median
of 5 x 10"5
Spectra 1995. Lehigh,
Alsen (Construction
Phase)
5
17
9x 10"7
1.7 x 10"4
4.4 x 10"5
2.5 x 10"5
Laboratory
Flexible wall
permeameter
Wet process.
Stockpiled
CKD prior to
use in capping.
Shelby samples
remolded in the
laboratory
Malcom Pirnie, 1997.
Independent Cement
Corp., Catskill, NY
(Preconstruction)
6
58
3.1 x 10"7
1.1 x 10"4
2.8 x 10"5
2.1 x 10"5
Laboratory
Flexible wall
permeameter
Wet process.
CKD as placed
in landfill cap.
Shelby samples
remolded in the
laboratory.
Malcom Pirnie, 1997.
Independent Cement
Corp., Catskill, NY
(Construction)
7
30
2.1 x 10"7
4.7 x 10"5
6.3 x 10"6
2.4 x 10"6
Laboratory
Flexible wall
permeameter
Conditioned
CKD
Samples collected by
Shelby tubes or
coring. Samples not
remolded.
RMT 1993. Lafarge,
Alpena, MI (Preliminary
Phase)
Draft: June 1998
6-15
-------
Entry
No.
No. Of
Tests
Minimum
Maximum
Average
Median
Test
Location
Test
Procedure
CKD Type
Comments
Reference
8
6
3.8 x 10"10
1.2 x 10"6
3.0 x 10"7
4.7 x 10"8
Laboratory
Flexible wall
permeameter
Conditioned
CKD
RMT 1994a.
Lafarge, Alpena, MI
(Design Phase)
9
20
2.6 x 10"8
1.0 x 10"5
4.0 x 10"6
3.0 x 10"6
Laboratory
Flexible wall
permeameter
Conditioned
CKD Test Plot
Lafarge 1996a.
Lafarge, Alpena, MI
(Design Phase).
10
7
1.4 x 10"6
1.7 x 10"4
3.8 x 10"5
4.5 x 10"6
Laboratory
Flexible wall
permeameter
Samples from
pile. Both
relatively
undisturbed and
remolded
samples.
Highest permeability
from relatively
undisturbed sample.
Remolded samples
show lower
permeability.
USEPA 1997b. Metalme
Falls, WA
11
12
4.5 x 10"6
1.5 x 10"4
4.0 x 10"5
2.3 x 10"5
Laboratory
Samples from
test plots
Field compaction
performed using
vibratory padfoot
rollers, tire tollers,
and other equipment.
Todres, H.A 1992.
Chanute, KS
12
3
5.1 x 10"4
3.0 x 10"3
1.7 x 10"3
1.5 x 10"3
Laboratory
Fixed wall
permeameter
Dust G from
long wet kiln.
Dust H from
long dry kiln.
Dust S from
alkali bypass
precalciner
system.
Light compaction to
86.5 to 76.2 pcf. Dust
S is minimum. Dust
H is maximum.
Todres et al. 1992.
Dust from 3 sources.
Draft: June 1998
6-16
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Entry
No.
No. Of
Tests
Minimum
Maximum
Average
Median
Test
Location
Test
Procedure
CKD Type
Comments
Reference
13
3
7.0 x 10"6
2.1 x 10"5
1.2 x 10"5
7.6 x 10"6
Laboratory
Fixed wall
permeameter
Dust G from
long wet kiln.
Dust H from
long dry kiln.
Dust S from
alkali bypass
precalciner
system.
Medium compaction
equivalent to
Standard Proctor.
43.7 to 81.0 pcf. Dust
H is minimum. Dust
S is maximum.
Todres 1992. Dust from
3 sources.
14
3
1.0 x 10"10
1.6 x 10"6
5.5 x 10"7
4.9 x 10"8
Laboratory
Fixed wall
permeameter
Dust G from
long wet kiln.
Dust H from
long dry kiln.
Dust S from
alkali bypass
precalciner
system.
Heavy compaction
equivalent to
Modified Proctor
108.2 to 84.2 pcf.
Dust G is minimum.
Dust S is maximum.
Todres et al. 1992.
Dust from 3 sources.
15
20
2.6 x 10"7
2.7 x 10"5
8.5 x 10"6
4.9 x 10"6
Laboratory
Flexible wall
permeameter
Conditioned
CKD - Dry
process.
Core samples taken
from test plots
compacted with
scrapers or rollers.
RMT 1996a. Medusa
Cement Company,
Charlevoix, MI (design
phase).
Draft: June 1998
6-17
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Density
The density of soils and soil-like materials depends on the specific gravity of the solid material, the
porosity or void ratio, the moisture or degree of saturation of the material, and the particle size
and particle size distribution. As described in the foregoing part of this section, compaction
increases density and maximum density is achieved at the optimum degree of saturation.
For most of the actual field test data available, maximum dry density is determined by standard
Proctor tests and field verification of density is determined indirectly using a nuclear source.
Where field tests show less than required density, recompaction is required and indirectly it is
assumed, subject to permeability tests, that when the in-place density is within stated limits, the
permeability of the material will also be within stated limits. In short, the in-place density is
related to compaction, the resulting permeability is also related to compaction, and the starting
point is the determination of maximum dry density in terms of standard tests.
A typical range of maximum dry density for CKD was reported in the closure of the Independent
Cement Corporation CKD landfill in Greene County, New York (Pirnie, 1997). In twelve (12)
tests conducted, the maximum dry density determined by the standard Proctor test (ASTM 698)
ranged from 73.8 pcf with a corresponding moisture content of 36.2 percent to 88.6 pcf with a
corresponding moisture content of 23.3 percent.
In the medium compaction tests conducted by Todres et al. (1992), maximum dry density was
determined using a compaction method similar to the standard Proctor test. In these tests, the
maximum dry density was determined to be:
Selected data on maximum dry density and optimum moisture content for CKD are provided in
Table 6-2. As shown in Table 6-2, variations in test results indicate needs to establish
density/moisture relationships using CKD specific to a location during design of closure or landfill
facilities.
CKD possesses other characteristics that are also to be considered in the evaluation of its use in
liners or caps. Several of those characteristics are addressed below.
Reaction with Water
CKD is highly dehydrated in its generated form due to the thermal treatment it receives in the kiln
system. The action of absorbing (rehydrating) releases a significant amount of heat from the
long wet rotary kiln dust:
long dry rotary kiln dust:
recalciner dust:
93.7 pcf
83.0 pcf
81.0 pcf
6.4.1.3
Other Characteristics of CKD
Draft: June 1998
6-18
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Table 6-2. Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) for CKD
Entry
No.
No. Of Tests
Average
Compaction
Material
Comment
Reference
MDD (pcf)
OMC (%)
1
12
79
34
Standard Proctor
ASTM D698
CKD, wet process
Samples for in-
place material
prior to closure.
Pirnie 1997.
Independent Cement,
Green County., New
York.
2
2
67
50
ASTM D698
Dry process and
moisture conditioned
CKD
RMT 1996a. Medusa
Cement, Charlevoix,
MI.
3
1
94
18
Similar to
ASTM D698
CKD
Dust "G", wet
process.
Todresetal. 1992.
4
1
83
27
Similar to
ASTM D698
CKD
Dust "H", dry
process.
Todresetal. 1992
5
1
81
29
Similar to
ASTM D698
CKD
Dust "S",
precalciner
system.
Todresetal. 1992
6
1
67
23
ASTM D698
CKD
CKD from pile.
Dames and Moore
1996. Lehigh, Metaline
Falls, WA
Draft: June 1998
6-19
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non-weathered dust (USEPA, 1993b). A temperature of 101 °C (214°F) was recorded when
water was added to one of the CKD samples being tested to determine density and moisture
relationships, with the generation of large volumes of steam. Sample preparation included
overnight storage of the samples in capped containers at 100 percent relative humidity to allow
hydration to occur (Todres et al., 1992).
In a report of studies on the use of CKD as a landfill liner conducted at the University of
Sherbrooke in Sherbrooke, Quebec, the stabilization of CKD is said to depend on the control of
the expansion reactions that result from "the hydration of combinations of elements such as
sulphate, alumina, lime, silica and alkalis" which produce high volume, low density mineral phases
such as erringite, valerite, thaumasite and portlandite (Ballivy et al., 1992). In these studies,
mixtures of CKD with fly ash and/or silica fume were analyzed to determine potential
effectiveness as a liner for sanitary landfill sites. The results of the studies show 28 day
compressive strengths for CKD/fly ash/silica fume mixtures in the range of 17.7 to 30.0
megapascals (Mpa) [2,560 to 4,350 pounds per square inch (psi)] and permeability in the range of
about 5xl0"9 to 5xl0"8 cm/sec developed in 28 days. [The 28 day strength specified for concrete is
typically specified in the range of 17.2 to 34.5 Mpa (3,000 to 5,000 psi).]
The Ballivy et al. report concludes that the expansion effect expected due to hydration may be
offset by the pozzolanic reactions which produce C-S-H gel that occur when silica fume is added
to the CKD. Permeability studies showed all CKD/fly ash/silica fume mixes attaining
permeabilities less than 1 x 10"7 cm/sec using distilled water.
To test the potential effectiveness of CKD/fly ash/silica fume liners, leachate water from a sanitary
landfill was used. This leachate was characterized as slightly acidic (pH 6.82 SU) with "a strong
concentration of calcium, sodium, magnesium, manganese, iron (141.5 mg/C) and zinc (1.55 mg/C)
and low concentrations of copper, nickel, chloride and lead." The results of the testing showed a
rapid increase in pH to a plateau of about 12 SU and attenuation of metals present in the landfill
leachate to levels close to Province of Quebec standards. The effectiveness in metals removal is
attributed to the availability of high levels of alkalis for heavy metal precipitation and high pH
conditions (Ballivy et al., 1992).
The studies conducted by Ballivy do not address testing on samples containing 100 percent CKD,
although one of the mixtures contained CKD and silica fume only, with silica fume representing
only 1 percent of the weight. Compaction and compressive strength tests were conducted in
accordance with applicable ASTM Methods. Permeability testing was conducted using "radial
permeameters in the convergent mode" said to be an experimental apparatus with an accuracy of
±0.8 percent (Ballivy et al., 1992).
Observations of the strength of CKD as placed in landfills is also of interest. When stored fresh,
unconditioned CKD is a fine, dry dust that readily absorbs water. CKD can retain these
characteristics within the pile while developing an externally weathered crust due to absorption of
moisture and cementation of dust particles on the surface of the pile (USEPA, 1993b). Findings of
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6-20
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conditions at the Metaline Falls, Washington, CKD disposal site indicate, however, that at that
location, although the CKD dries to form a crust, a high moisture content commonly prevails
within a few inches of the surface, where the CKD is very soft (Dames and Moore, 1996).
Compatibility with Leachate
Design of any landfill liner system requires consideration of the chemical properties of the leachate
to be generated within the landfilled area and the potential impact the chemicals present in the
leachate may have on the lining system. In the case of a CKD landfill, the leachate to be
generated is expected to be highly alkaline and expected to contain some of the metals present
within the CKD. Evidence of metals in CKD leachate, simulated by leaching tests, has been
reported (USEPA, 1993b).
There are currently no landfill-generated CKD leachate data available. The Ballivy report, cited
above, addresses potential leachate quality using a municipal landfill leachate and a CKD material
mixed with fly ash and/or silica fume. These results indicate the generation of leachate with a high
pH and some metals present. While no conclusive evidence is provided for 100 percent CKD
material, the Ballivy findings suggest that releases through a CKD liner could be expected to
show elevated pH and some metals, characteristic of CKD, present in the liquid released. The
long term performance of a compacted CKD liner within a CKD landfill, subjected to a continuing
supply of leachate of elevated pH from overlying layers of CKD that are more loosely compacted,
has not been studied.
6.4.2 Analysis of Instances Where CKD Was Considered or Used for a Landfill Liner or
Cap
Currently available information shows several locations where CKD has been proposed or used as
either a liner or cap at CKD landfill/CKD disposal locations. These locations include several in
New York, two in Michigan and one in Washington. A brief overview of each location and
engineering considerations relating to liner or cap effectiveness are summarized in the following
sections.
6.4.2.1 Lehigh Portland Cement Company - CKD Disposal Areas - Green County,
New York
Lehigh Portland Cement Company (Lehigh) has operated two cement plants in Greene County,
New York. One facility is located near Cementon, the other near Alsen. Neither of these Lehigh
plants are currently active (Per. Com. Kircher, 1997). The properties owned by Lehigh, including
quarries, plant sites and disposal sites are adjacent to one another and comprise about 2,440 acres
located just west of the Hudson River, about 35 miles south of Albany (CHA, 1990). CKD
permeability and density data were collected at two CKD disposal facilities associated with
Lehigh's Greene County plants: the Lehigh Dust Disposal Landfill, Cementon, NY; and the
Lehigh Dust Disposal Facility, Alsen NY.
Draft: June 1998
6-21
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6.4.2.1.1 Lehigh Dust Disposal Landfill, Cementon, New York
Overview
The Lehigh Cementon CKD landfill is located just east of the Hamlet of Cementon, about 600
feet west of the Hudson River. The landfill site comprises about 20 acres of property owned by
Lehigh, located about 500 feet southwest of Lehigh's Cementon Cement Plant property, as
described in a Clough, Harbor and Associates (CHA) closure report prepared in 1986 (CHA,
1986a). An estimated 547,000 cubic yards of CKD have been placed on the site. This CKD
landfill was closed in 1988 (CHA, 1989).
Closure and Design and CKD Tests Prior to Construction
The closure design proposed to the New York State Department of Environmental Conservation
(NYSDEC) included an 18-inch cap of fresh CKD compacted in 6-inch (15 cm) lifts, covered by 6
inches of topsoil material capable of supporting vegetative growth (CHA, 1986b). The report
cites results of tests of CKD engineering properties in support of applications to construct and
operate Lehigh's solid waste facility for the neighboring Alsen plant. (The Alsen facility is
discussed in the following section of this document.) CKD is reported as a fine grained material
of low density (35 to 65 pcf, uncompacted). A grain size analysis shows 100 percent of the dust
particles finer than a No. 200 sieve (75 //m), 92 percent finer than 25 //m, 62 percent finer than
18/iin, 13 percent finer than 13 jj,m, 8 percent finer than 9 //m, 7 percent finer than 6.5 /j,m and 6
percent finer than 4.5 jim (CHA, 1986a).
Maximum dry density, established using standard proctor tests, was reported to be 1,530 kg/m3
(95.2 pcf) at an optimum water content of 24 percent. At 90 percent proctor compaction, a
coefficient of permeability of 8.1 x 10"7 cm/sec was reported (CHA, 1986a). Additional
information on CKD permeability is provided in Supplement No. 1 to the CHA report, which cites
findings of tests performed at Rennselaer Polytechnic Institute (RPI) by Dr. Thomas F. Zimmie.
In these tests, fresh CKD from Lehigh's Cementon Plant was used. Compaction and associated
permeability were reported as follows:
• CKD compacted dry of optimum (Water content, W=17.5%4): 3.2 x 10"8cm/sec
• CKD compacted at optimum (W = 20.9%): 6.7 x 10"9cm/sec
• CKD compacted wet of optimum (W = 23.5%): 2.7 x 10"8 cm/sec
The report concludes that the compacted fresh CKD is a material suitable from construction of
the dust pile closure cap and can meet a cap permeability criterion of 1 x 10"7 cm/sec (CHA,
1986a).
Construction and Results of Verification Tests
In a letter to the NYSDEC on February 8, 1989, CHA provides the results of the closure
4 W = Weight of water/weight of solids or moisture content in %.
Draft: June 1998
6-22
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certification for Lehigh's Cementon CKD pile (CHA, 1989). This letter reports that closure of
the CKD pile was conducted during the period June through November, 1988.
A test panel was constructed on top of the CKD pile in June 1988 for the purpose of verifying the
compaction and permeability characteristics of the CKD material during closure. Four (4) 30 cm
(12-inch) CKD lifts were placed within the test area and a nuclear density meter was used to test
the compacted CKD for density, moisture and compaction. Results of twenty (20) tests
conducted on June 14, 1988 in the test panel area show:
• wet density in the range of 1,595 kg/m3 to 1,845 kg/m3 (99.3 to 114.7 pcf);
• moisture in the range of 41 to 60 percent; and
• percent compaction in the range of 93 to 114 percent of Proctor compaction.
Compaction was afforded using a sheepsfoot and steel drum roller, with highest densities
recorded for 6 passes of the compaction equipment.
Shelby tube (undisturbed) samples of compacted CKD were collected in the field for triaxial
permeability testing at the RPI laboratory. Laboratory personnel were unable to retrieve
workable samples from the Shelby tubes. An alternative method for determining the undisturbed
permeability of the compacted CKD in the field was adopted in consultation with the NYSDEC.
In this method a four (4) foot section of rigid plexiglass tubing, 2.6 inches in diameter, is
advanced 12 inches into the compacted CKD. The tube is filled with dye-colored water, and the
drop in water level with time is measured to simulate a falling head permeability test (CHA,
1989).
The permeability testing was conducted over a period of about seven (7) weeks. NYSDEC also
approved the installation field permeability testing apparatuses with tubing of 2.6 inch or 2.0 inch
at other locations on the CKD pile in lieu of trying to retrieve undisturbed CKD samples. The
results of the fifteen (15) in-field permeability tests are shown in Table 6-3.
The letter concludes with a statement to NYSDEC indicating that the CKD pile should now be
considered fully closed and in its final state (CHA, 1989). Variations in permeability by location
and time are not addressed in the report.
Draft: June 1998
6-23
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Table 6-3: Lehigh Cementon, NY - CKD Landfill Closure Field Permeability Test Results
Date
Location 1
Location 2
Location 3
Location 4
9/7/88
4.1 x 10"6
—
—
—
9/8/88
3.2 x 10"6
—
—
—
9/12/88
2.3 x 10"6
—
—
—
9/14/88
2.0 x 10"6
—
—
—
9/19/88
2.5 x 10"6
—
—
—
10/18/88
—
1.8 x 10"6
1.2 x 10"5
2.5 x 10"5
10/20/88
—
2.5 x 10"6
5.2 x 10"6
1.0 x 10"5
10/25/88
7.9 x 10"7
3.0 x 10"6
5.9 x 10"6
9.6 x 10"6
Source: CHA 1989.
Note: Results expressed in cm/sec. See text for explanation of test method.
6.4.2.1.2 Lehigh Dust Disposal Facility - Alsen, NY
Overview
Lehigh's Alsen Dust Disposal Facility is located on Lehigh property southeast of the Hamlet of
Alsen, east of the now inactive Alsen Cement Plant, Town of Catskill, Green County, New York.
The facility is bordered to the north by Independent Cement Corporation property, to the east by
the Hudson River, to the south by Lehigh's Cementon Plant property, and to the west by quarries
(Dunn 1992). The site comprises about 13 acres (CHA, 1987).
On May 7, 1987, Lehigh entered into an Order on Consent with the NYSDEC for the closure of
the facility (Dunn, 1992). At the time of final closure, the facility contained an estimated
1,400,000 cubic yards of CKD (Spectra, 1995).
Closure was conducted in three phases so that approximately one third of the facility could be
graded, capped, topsoiled, and closed in each of three successive years. Phase I of the closure was
conducted in the period of July-November 1992, Phase II in the period of August-November
1993, and Phase III in March-June 1994.
Closure Design and CKD Tests Prior to Construction
Closure plans called for the facility to be capped with 54 inches (1.37 m) of compacted CKD
following grading and shaping of the dust pile. The cap was to consist of three 18-inch (46 cm)
layers, each comprising two 9-inch (23 cm) compacted lifts. Phase I and II of the closure were
conducted using this method. The closure report notes that while the results of the Phase I and
Phase II closures were satisfactory, control of lift thickness was difficult and compaction on the
Draft: June 1998
6-24
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side slopes (3 horizontal: 1 vertical) was very time consuming.
Test results for CKD permeability used in the closure design are provided for samples from the
kiln, the existing pile, and test panels. Table 6-4 summarizes the test results.
According to the Dunn report (Dunn, 1992a), the fresh CKD was compacted to a maximum dry
density of 90 pcf and laboratory permeability tests were performed at various moisture contents,
both dryer and wetter than optimum. It was concluded that there was no significant change in
permeability with moisture content for the fresh CKD, given the reported range in permeability
from 1.6 x 10"6 to 7.7 x 10"7 cm/sec (Dunn, 1992a).
The weathered CKD was found to have a permeability of 2.7 x 10"5 cm/sec. Field test panels
constructed of both fresh and weathered CKD demonstrates that actual in-place permeability
varies little between fresh and weathered CKD, with a reported range of 7.0 x 10"5 and 4.9 x 10"6
cm/sec (Dunn, 1992a).
Table 6-4: Results of CKD Permeability Testing Used in the Design of the
Alsen CKD Landfill Closure
No.
Permeability
Notation
1
7.7 x 10"7
Fresh CKD. Bulk Sample.
2
1.6 x 10"6
Kiln Dust. Bulk Sample.
3
9.7 x 10"7
Fresh CKD. Bulk Sample.
4
8.2 x 10"7
Fresh CKD. Bulk Sample.
5
7.8 x 10"7
Fresh CKD. Bulk Sample.
6
2.7 x 10"5
Old Alsen Landfill, as received. Bulk Sample.
7
1.5 x 10"5
Kiln Dust. Shelby Tube. Test Pad Sample.
8
4.9 x 10"6
Kiln Dust. Shelby Tube. Test Pad Sample.
9
7.0 x 10"5
Kiln Dust. Shelby Tube. Test Pad Sample.
Source: Dunn 1992a
Notes: Results expressed in cm/sec.
All tests were conducted in a laboratory using a flexible wall permeameter in accordance
with ASTM D5084-90.
Testing required before and during construction (closure) included the following (Dunn, 1992a):
• Soil particle size analysis;
• Atterberg limits;
Draft: June 1998
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• Lab permeability test (triaxial cell);
• Moisture content;
• Moisture density relationship;
• In-place density tests;
• In-place moisture; and
• Lab permeability.
Construction and Results of Verification Tests
The results of testing conducted during site closure are available in the closure certification report
(Spectra, 1995). The results of 33 permeability tests are reported (of which 9 test results are
illegible). The results of the permeability testing showed, for the 24 results, a range of
permeabilities from 1.6 x 10"4 cm/sec to 2.7 x 10"6 cm/sec, with an average of 6.8 x 10"5 cm/sec,
and a median value of 5 x 10"5 cm/sec.
Various notations are included in the test results, indicating some difficulty in testing procedures.
The results of the permeability testing are summarized in Table 6-5. As shown in Table 6-5,
where Shelby tube samples were recompacted, resulting permeability values are somewhat lower
(e.g. less permeable) and samples which were noted as "brittle" show somewhat higher
permeabilities. Whether the brittle nature of samples resulted from loss of moisture after sample
collection or whether the in-place material was brittle, is unknown. The nine samples indicated as
"undisturbed" may be most representative of in-place conditions. As shown in Table 6-5, these
samples showed a range in permeability from 2.9 x 10"6 to 1.6 x 10"4 cm/sec and a median
permeability of 5.1 x 10"5 cm/sec.
In the closure report, it was noted that Shelby tubes were extracted from compacted layers of
CKD throughout all phases of the closure and in the majority of cases, the density of CKD was
such that the Shelby tubes deformed (e.g., while the Shelby tubes were being pushed into the
CKD, the walls of the tubes deformed) (Spectra, 1995). This may have accounted for some of
the difficulties reported in the permeability data.
Proctor testing showed an optimum moisture content of 50 percent, but over three years of
testing, a moisture content in the low 40 percent range was found to be the most desirable to
avoid rutting and shrinkage cracks in the CKD as placed. The average moisture content for the
715 density tests performed during closure was 40.5 percent (Spectra, 1995).
Draft: June 1998
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Table 6-5: Results of CKD Permeability Testing During Closure of the
Alsen CKD Landfill
No. Of
Sample Results
Minimum
Maximum
Average
Median
Notations
24
2.7 x 10"6
1.6 x 10"4
6.82 x 10"5
5.05 x 10"5
All Samples
6
2.7 x 10"6
8.1 x 10"5
3.63 x 10"5
3.2 x 10"5
Notation showing "shelby
tube/recompacted"
9
2.3 x 10"5
1.5 x 10"4
8.58 x 10"5
8.2 x 10"5
Notation showing "Sample in tube wa;
dry and brittle", "Sample was dry and
brittle and had to be recompacted",
'Filter page clogged; only one
permeability run was made", or no
notation (one sample)
9
2.9 x 10"6
1.6 x 10"4
7.33 x 10"5
5.1 x 10"5
Notation showing "Undisturbed tube
sample"
Source: Spectra 1995.
Note: Permeability values in cm/sec.
In-place density tests were performed using the Sand Cone Method (ASTM 1556) and the
Nuclear Density Method (ASTM D292), 73 tests and 642 tests, respectively. In the final phase of
closure, 215 nuclear density tests were performed with more than 94 percent of the test showing
values exceeding 95 percent of Proctor Density, which was required. Where tests showed values
less than the 95 percent Proctor Density, recompaction was performed (Spectra, 1995).
The spectra report concludes, in part, that the closure report and documentation serves to verify
that the closure was accomplished in accordance with stated plans and procedures, with
modifications or deviations identified and justified (Spectra, 1995).
6.4.2.1.3 Lehigh's Alsen Quarry CKD Disposal Landfill
Overview
Lehigh's Alsen Quarry Landfill site is located in an unused portion of Lehigh's quarries situated
southwest of the Hamlet of Alsen, about 4,500 feet west of the Hudson River. In September
1990, an application pursuant to NYSDEC's Part 360 Solid Waste regulation was made to the
NYSDEC for renewal of a Part 360 permit issued to Lehigh in 1981 for use of the Alsen Quarry
CKD landfill. At the time of the application, Lehigh's Alsen plant was not in operation, but the
Lehigh Cementon plant was producing CKD at an annual rate of about 55,000 tons or about
50,000 cubic yards (CHA, 1990).
Closure Design and CKD Tests Prior to Construction
The landfill liner design proposed consisted of a single 18-inch layer of compacted CKD installed
in 3 lifts, each 6 inches thick. No leachate collection system was proposed. The final cap
Draft: June 1998
6-27
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proposed consisted of an 18-inch layer of CKD, compacted in 6-inch lifts overlain by 6 inches of
topsoil to support vegetative growth.
The permeability of the compacted CKD was said to be less than 1 x 10"7 cm/sec (CHA, 1990).
The source of this information on CKD permeability was not found in the applications, but
apparently it may have been based on the tests cited in the CHA 1986 closure design (CHA,
1986a) for the Cementon CKD landfill.
Status
Whether NYSDEC granted approval to Lehigh to construct the Quarry landfill is unclear, but it
was considered by Lehigh to be a temporary facility only (Dunn, 1992b). Lehigh has not pursued
construction of the Quarry Landfill (Per. Com. Kircher, 1997).
6.4.2.2 Independent Cement Corporation - CKD Landfill - Green County, New
York
Overview
The Independent Cement Corporation (ICC) property comprises about 2,200 acres located north
of and adjacent to the Lehigh Cement Corporation property described in Section 6.4.2.1.2. The
ICC CKD landfill comprises about 29 acres located just west of the Hudson River. The landfill is
undergoing a phased closure under an Order on Consent entered into between ICC and NYSDEC
in July 1994 (SGY, 1995).
The closure is to take several years, with on-going operations of the ICC cement plant to continue
generating CKD at 100,000 tons per year to supply required CKD to the landfill for two years,
with a decrease in ensuing years to result in closure in 1998 (SGY, 1995).
Closure Design and CKD Tests Prior to Construction
The cap proposed in the closure plan consists of three (3) 46 cm (18-inch) CKD layers, each
compacted in two 23 cm (9-inch) lifts, bringing the overall thickness of the CKD cap to 1.37
meters (54 inches) (SGY, 1995).
The revised closure design cites physical characteristics and engineering properties for CKD based
on prior studies of CKD generated at ICC. The CKD is described as a fine-grained material of
low density (35 to 65 pcf). A grain size analysis of the ICC CKD, taken from the SGY report, is
provided in Table 6-6. The CKD is described as "having a grain size distribution approximately
that of a silt" (SGY, 1995).
Draft: June 1998
6-28
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Table 6-6. CKD Grain Size Analysis, Independent Cement Corporation,
Greene Co., New York
Particle Size
percent Finer by Weight
1/4" Sieve
100
#10 Sieve
99.8
#40 Sieve
99.5
#200 Sieve
85.7
#270 Sieve
82.6
0.035 mm
81.8
0.025 mm
79.6
0.018 mm
77.3
0.013 mm
65.4
0.009 mm
56.4
0.0065 mm
19.5
0.0045 mm
9.2
0.0034 mm
8.5
0.0015 mm
3.5
Source: SGY 1995
The closure report cites the properties of CKD from the ICC plant and other cement plants as
similar, owing to the nearly identical nature of the process of their origin and refers to data from
other manufacturers indicating that fresh compacted CKD has been shown to be able to achieve a
permeability of less than 1 x 10"7 cm/sec. The fresh CKD compaction and permeability data from
Lehigh's Cementon Plant (see Section 6.4.2.1.1) was cited as typical.
Construction and Results of Verification Tests
The closure is being conducted in three phases; Phase I, Phase II, and Phase III. Phase I
consisted of site surveying and rough grading and started in November 1995 (Pirine, 1997).
Grading and compaction of existing weathered CKD to provide a subgrade of the cap was started
in July 1996. Compaction was provided with a self-propelled vibratory roller. Placement of the
low permeability cover layer, which consisted of weathered and freshly generated CKD, was
placed on the subgrade layer in July and August 1996. The low permeability layer was placed in
six 9-inch lifts to form a 1.37 m (4.5 feet) compacted CKD cap over approximately 9 acres. Each
lift was compacted to 95 percent of the maximum standard Proctor density of the most
representative material using a smooth drum roller (Pirnie, 1997).
A total of 567 in-place density tests, using a nuclear densitomer (ASTM D2922), and 61
laboratory tests (ASTM D5084) to determine permeability of samples taken using Shelby tubes,
Draft: June 1998
6-29
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were performed (Pirnie, 1997). The laboratory reports indicate that all samples were remolded
and compacted, resulting in the potential that laboratory permeabilities are less than actual in-
place permabilities. The permeability tests for 58 samples are summarized in the report. Data for
percent moisture and percent compaction (as a percent of maximum standard Proctor density) are
also provided with the permeability data. For the 58 tests reported for July 9, 1996-September
16, 1996, the permeability test results show the following:
• Maximum Permeability 1.1 x 10"4 cm/sec
• Minimum Permeability 3.1 x 10"7 cm/sec
• Average Permeability 2.8 x 10"5 cm/sec
• Median Value of Permeability 2.1 x 10"5 cm/sec
The percent moisture ranged from 18.2 percent to 46.2 percent and compaction ranged from 73.7
percent to 109.7 percent of maximum standard Proctor density.
The certification report noted that due to the low moisture content of the source material used in
the cap (the CKD to be used) Atterberg limit tests were not performed, noting that CKD exhibits
non-plastic characteristics. The certification report further noted that several test results showed
compaction not in accordance with specifications, but since testing of source material showed
acceptable permeability at lower densities, the cap placed in 1996 provided a low permeability
cover system meeting the intent of the closure plan (Pirnie, 1997).
The topsoil layer was placed over the CKD layer, graded and seeded in October 1996 (Pirnie,
1997).
6.4.2.3 Lafarge Corporation - CKD Landfill - Alpena, Michigan
Overview
The Lafarge Corporation cement plant in Alpena, Michigan is located northeast of the City of
Alpena. Limestone has been mined from a quarry at this site since the early part of the century.
Lafarge has owned the quarry and operated the plant since 1986 (RMT, 1994b). The quarry is
located about 600 to700 feet from Lake Huron and comprises approximately 600 acres.
The quarry is being mined to a depth of about 100 to 120 feet below ground surface. The local
topography is relatively flat, and the bottom of the quarry is about 60 to 80 feet below the
elevation of Lake Huron. A dewatering system is operated at the quarry to collect ground water
and surface water. The water is discharged to Lake Huron via an NPDES permitted outfall at a
rate of 0.4 to 2.7 million gallons per day (RMT, 1994b).
In 1995, Lafarge generated 199,208 metric tons of CKD waste. Since Lafarge has operated the
plant, CKD has been disposed in the southeastern portion of the active quarry at a location
referred to as the "existing CKD Placement Area". Crushed limestone and shale, gypsum, coal
rejects, clinker, cement and other material have been placed in the western part of the quarry at a
Draft: June 1998
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location known as the "Wessel Road Site" (RMT, 1995).
In a letter of September 21, 1991 to Lafarge, the Michigan Department of Natural Resources
(MDNR) (now known as the Michigan Department of Environmental Quality - MDEQ), MDNR
informed Lafarge that CKD disposal in the quarry is regulated under the Michigan Solid Waste
Management Act (SWMA). Lafarge disagreed, citing prior approvals under the Reclamation of
Mineral Act. To settle the matter, Lafarge and MDNR signed a Consent Judgment in December
1994 which outlines a compliance program for CKD management (RMT, 1995).
CKD Test Plot Data - 1992 and 1993
In June 1993, RMT, Inc., consultants to the Lafarge Corporation, submitted a report to the
MDNR summarizing results of field testing of CKD placed in test plots located in the Lafarge
quarry in Alpena (RMT, 1993). The report includes the results of both field and laboratory
testing performed to determine the properties of CKD which was treated by adding water, mixing
and compacting.
Moisture conditioned CKD was placed in eight (8) test plots. Two methods were used for
moisture conditioning and CKD placement. In the first method, the CKD was placed in a pug
mill, water was added, the CKD was mixed with the water in the pug mill, the mixture was
transferred in a conveyor belt, and additional water was added as the CKD was dropped into a
scraper or into a stockpile. CKD dropped into a scraper was transported directly to the test plots
for placement. Stockpiled CKD was locaded into a scraper by an end loader and then transported
to the test plots for placement. The CKD was placed using a scraper. In the second method, a
concrete truck was used. Water was added to the dry CKD in the truck, as the barrel of the
concrete truck was rotated. When the desired moisture content was achieved, the truck
transported the CKD to the test plots, where the CKD was placed using the truck's concrete
chute.
The moisture content of the CKD was varied and the CKD was placed in the test plots in 3-inch,
6-inch, and 12-inch layers.
The results of the permeability testing are shown in Table 6-7.
As shown in Table 6-7, the test results indicate a range of CKD permeabilities from a minimum of
2.1 x 10"7 cm/sec to a maximum of 4.7 x 10"5, an average of 6.3 x 10"6 and a median value of 2.4 x
10"6.
Draft: June 1998
6-31
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Table 6-7 Results of CKD Permeability Testing -
Test Plots at the Lafarge Facility - Alpena, Michigan
No.
Target Moisture
Content (%)
Layer Thickness
(inches)
Placement
Means
Permeability
(CMS/sec)
1
57
6
Truck
4.70E-07
2
57
6
Truck
2.40E-06
3
57
6
Truck
2.40E-06
4
57
6
Truck
2.60E-07
5
67
6
Truck
3.10E-06
6
67
6
Truck
3.20E-06
7
67
6
Truck
3.20E-06
8
67
6
Truck
1.90E-06
9
32
6
Truck
2.40E-06
10
32
6
Scraper
2.10E-06
11
32
6
Scraper
3.20E-06
12
32
6
Scraper
1.10E-05
13
28
6
Scraper
1.60E-05
14
28
6
Scraper
1.40E-05
15
28
6
Scraper
4.70E-05
16
28
6
Scraper
2.60E-05
17
67
6
Truck
3.30E-06
18
67
6
Truck
9.70E-07
19
67
6
Truck
9.90E-07
20
67
6
Truck
2.30E-06
21
67
3
Truck
2.20E-06
22
67
3
Truck
3.10E-07
23
67
3
Truck
2.70E-06
24
67
3
Truck
7.90E-07
25
67
12
Truck
4.20E-07
26
67
12
Truck
2.00E-06
27
32
6
Scraper
2.10E-07
28
32
6
Scraper
4.50E-06
29
32
6
Scraper
6.40E-06
30
32
6
Scraper
2.40E-05
Maximum
4.70E-05
Minimum
2.10E-07
Average
6.32E-06
Median
n /irYP_nA
Draft: June 1998
6-32
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Some of the principal findings of the RMT report (RMT, 1993) are summarized below:
• At moisture contents greater than 38%, the CKD was too wet to be workable
using scraper. At moisture contents less than 15%, the CKD was too dry. RMT
notes that controlling blowing CKD could be a problem. RMT reports that
moisture conditioned CKD is easily placed with a scraper when the moisture
content is between approximately 15% and 38%.
• At moisture contents of less than 54%, the CKD was too thick to remove from the
concrete truck. Moisture conditioning CKD in a concrete truck was acceptable for
moisture contents of 57% or greater according to RMT.
• Steam generation was observed 1 to 2 hours after CKD was placed in the tests
where moisture contents ranged from 28% to 57%. The boiling temperatures
were reported to be caused by hydration of the CKD.
• Visible cracking was observed on all of the test plots. The cracks ranged from
hairline cracks only a few inches long to larger cracks, approximately 1/8 inch to
1/4 inch wide, 2 to 6 inches deep, and 2 to 5 feet long.
• The RMT report notes that the method of placement and average density due to
compaction had a statistically significant effect on hydraulic conductivity, with
higher dry density corresponding to lower permeability.
Closure Designs and Closure Design Data
A March 8, 1995 letter from the MDNR to Lafarge (MDNR, 1995) addresses an Interim Closure
and Action Plan submitted on November 18, 1994 (RMT, 1994a). In the letter, MDNR approved
the use of conditioned CKD as an interim cover, but required further evaluation of CKD proposed
as a final cover.
The final closure, maintenance, and monitoring plan (RMT, 1995) refers to the MDNR letter of
March 8, 1995 and refers to the construction Quality Assurance Plan as specifying that CKD
liners will be constructed to meet a permeability of 1 x 10"7 cm/sec. Citing a reduced CKD
generation rate resulting from Lafarge investment in new raw materials, the final closure report
(RMT, 1995) proposes:
• capping of the Wessel Road site with a geomembrane in lieu of a CKD cap;
• capping the existing CKD placement area with a combination of a geomembrane
on the side slopes and a CKD barrier of a thickness of 6 feet over the upper slopes.
In the HELP Model evaluation of landfill leakage conducted in support of the proposed closure
method for the existing CKD placement area, RMT used a 24-inch layer of CKD with a
Draft: June 1998
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permeability of 1 x 10"7 cm/sec, and notes that the actual thickness is 6 feet (RMT, 1995). The
closure report makes reference to earlier studies demonstrating the low permeability of
conditioned and compacted CKD. Presumably, the earlier studies are those reported in Appendix
L of the Interim Closure Plan (RMT, 1994a). These permeability data are shown in Table 6-7.
New CKD Landfill - 1994 Design
In the Type III Landfill Design Report (RMT, 1994b) a new CKD landfill was proposed, to be
located within the quarry, just north of the existing CKD placement area. The proposed landfill
would occupy about 112 acres. In the report, RMT assesses a landfill liner design consisting of a
6-foot layer of conditioned CKD, overlain by a 12-inch drainage layer of secondary crusher stone
and a non-woven geotextile over the drainage layer. The design also calls for water collection
drains above the conditioned CKD base, manholes to collect the water and a pump and force main
to remove collected water to a holding tank (RMT, 1994b).
RMT proposed capping the landfill at closure with conditioned CKD in phases. As the waste
CKD is placed and brought up to grade a 12-inch drainage layer (secondary crushed stone) would
be placed above the landfilled waste CKD, covered with a non-woven geotextile and topped with
a 6-foot layer of conditioned CKD. The conditioned CKD would be covered by a 2-foot general
fill erosion layer. In its modeling runs, RMT used a permeability for CKD of 1 x T1 cm/sec.
The design report (RMT, 1994b) also provides information on strength properties of CKD.
Compressive strength of 28-day old samples ranged from 53 pounds per square inch (psi) to 240
psi, with most samples showing strengths equal to or greater than 100 psi.
Results of laboratory testing of permeability (using flexible wall permeameter) of conditioned
CKD in the period 12/19/94 through 2/20/95 are provided in an October 30, 1996 letter from
Lafarge to the MDEQ (Lafarge, 1996a). The results of 20 samples show a range of permeabilities
from 2.6 x 10"8 cm/sec (minimum) to 1 x 10"5 cm/sec (maximum), with an average of 3.99 x 10"6
cm/sec and a medium value of 2.95 x 10"6 cm/sec.
Revised Designs
In December 1996 Lafarge sent a letter to the MDEQ requesting approval of two conceptual
alternatives to the design of cell 1 of the new landfill proposed in the quarry (Lafarge, 1996d).
The letter outlines the conceptual design alternatives as follows:
• Alternative 1 - The approved alternative. A base of conditioned CKD with a permeability
of 1 x 10"7 cm/sec, 6 feet thick, overlain by a 1 foot drainage layer.
• Alternative 2 - A proposed alternative. A base of general fill, 6 feet thick, overlain by a
geomembrane (40 mil minimum thickness) and a 1 foot drainage layer overlying the
membrane.
• Alternative 3 - A base of general fill, 3 feet thick, overlain by select clay fill with a
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permeability of 1 x 10"7 cm/sec and thickness of three feet and a 1 foot drainage layer
overlying the clay.
Citing the ease of construction, the availability of materials, and uncertainty concerning the results
of the CKD pilot test program, the letter requests approval, with details to follow after a decision
by Lafarge in early 1997 (Lafarge, 1996d).
Submittals by Lafarge to the MDEQ in early 1997 indicate substantial changes to the closure and
new CKD landfill designs originally proposed. A February 20, 1997 letter indicates that the
barrier layer originally proposed for the cap of the existing CKD placement area (a conditioned
CKD layer two feet thick) was replaced with a geosynthetic clay liner (Lafarge, 1997b).
Current New Landfill Design - Cell 1
For the new landfill area, major changes in the design are also seen. Details of the current design
for Cell 1 indicate that the liner will be a 60 mil high density polyethylene (HDPE) membrane,
overlain by a drainage layer of sand, 2 feet thick (RMT, 1997). Plans showing the latest capping
details were not found. An April 18, 1997 letter from Lafarge to MDEQ indicates that a geonet
drainage layer is now proposed to overlay the HDPE liner in lieu of the drainage layer shown on
the March 1997 drawings (Lafarge, 1997c). No further information was found in MDEQ files
reviewed on April 24, 1997.
6.4.2.4 Medusa Portland Cement Company - Charlevoix, Michigan
Overview
The Medusa Portland Cement Company (Medusa) owns and operates a cement manufacturing
plant located about one mile west of the City of Charlevoix, Michigan. The Medusa property is
bounded to the north and west by Lake Michigan (RMT, 1996b).
The facility has been in operation since 1968. Since 1980, the company has used a dry process.
A total of 2 million tons of CKD has been disposed on the site since 1968. The company has
identified 9 locations where CKD has been disposed, with 75 percent disposed above ground and
25 percent below ground. All disposal areas have been covered with overburden and seeded,
except one area which has been used since 1983 and is identified as Pile #9. The facility does not
burn any waste materials, does not currently reuse any wastes in the process and does not recycle
CKD back into the process (MDNR, 1994). In 1995, the plant produced 46,560 metric tons of
CKD.
The present quarry floor elevation is approximately 548 feet, which is approximately 31 feet
below Lake Michigan's water level. The Medusa facility and the surrounding area are within a
matured karst terrain, with sinkholes, closed depressions and vertical shafts that extend beneath
the ground surface (RMT, 1996b). The company discharges water at a rate of 8.5 million gallons
per day from the quarry to Lake Michigan (MDNR, 1994).
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Proposed Pile 9 Closure and New Type III Landfill
Under a plan for closure of existing CKD disposal areas and development of a new landfill, a new
landfill is proposed over the existing Pile 9 and the adjacent area, the plan calls for the bottom of
the new landfill to serve as the final cover for the waste piles. The base of the new landfill would
consist of a double liner of two 3-foot thick conditioned compacted CKD liners, separated by a
secondary collection system. The secondary collection system (i.e., leak detection system) would
be a 1-foot thick stone drainage layer. The landfill would be capped in phases with a 2-foot
compacted CKD barrier layer (infiltration layer) and a 2-foot vegetated general fill layer. Water
contacting the CKD (contact water) would be collected and used in CKD conditioning or would
be treated (RMT, 1996a).
CKD Testing Program - Medusa Site
A conditioned CKD testing program was conducted to evaluate the feasibility of using CKD as a
Type III landfill liner and final cap barrier layer. The purpose was to determine if the CKD is
capable of achieving a permeability of 1 x 10"7 cm/sec, whether it has adequate compressive
strength and whether it can attain its required permeability when placed in the field (RMT,
1996a).
The testing was conducted in two phases. In the first phase, laboratory analyses were performed
to assess whether a permeability of 1 x 10"7 cm/sec could be achieved in the laboratory and to
determine the compressive strength of the CKD. In the second phase, a field program was
conducted to verify the laboratory results under field conditions.
After laboratory testing showed acceptable permeability results, twelve (12) test plots were
constructed and conditioned CKD was compacted in 6-inch lifts at each test plot with either a
scraper or a roller. The scraper test plots were rolled 11 to 14 times (e.g., compacted by the tires
of the scraper) and roller compaction was conducted using a smooth vibratory drum with 4 passes
(RMT, 1996a). Diamond core bit samples of the compacted CKD, collected about 28 days
following placement, were tested in accordance with ASTM D6084 (flexible membrane
permeameter). The results of the tests are shown in Table 6-8.
As shown in Table 6-8, none of the test results show a permeability attained in the field of 1 x 10"7
cm/sec or less. The minimum permeability was 2.6 x 10"7 cm/sec and the maximum 2.7 x 10"5
cm/sec, with a median value of 4.9 x l"6 cm/sec.
The nine (9) tests reported for scraper compaction show a permeability range of 2.6 x 10"7 to 2.7
x 10"5 cm/sec, with a median value of 3.3 x 10"6 cm/sec. The overall range in reported
permeability is about two orders of magnitude for roller compaction and one order of magnitude
for the scraper (tire) compaction.
The compressive strength of CKD is reported to range between 180 pounds per square foot (psf)
and 575 psf using ASTM D2166 (Unconfined Compressive Strength of Cohesive Soil).
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Detailed studies of potential landfill settlement and slope stability were included. The analysis
indicated a potential for 0.7 feet settlement of the cover and 2.8 feet for the liner, given a total
thickness of CKD in the pile of 106 feet and time period of 30 years. Noting that the actual
settlement will typically be less than predicted, the report further notes that differential settlement
should not be excessive and settlement is not expected to cause problems in the long-term
operation of the landfill (RMT, 1996a).
The stability analysis was performed using a shear strength of 400 psf and a unit weight of 96 pcf
for the conditioned CKD. For the waste CKD, a shear strength of 1,750 psf was used. The
analysis concluded that the landfill will be stable (RMT, 1996a).
RMT. Inc. Conclusions Concerning CKD Permeability
In its conclusions, the report notes that field tests indicate that CKD may be compacted to attain
permeabilities as low as 2.6 x 10"7 cm/sec and further notes that placement and compaction
techniques will be refined to attain permeabilities of 1 x 10"7 cm/sec or less (RMT, 1996a).
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Table 6-8. CKD Permeability - Test Plots, Medusa Cement Company
Charlevoix, Michigan
Test No.
Permeabilitv (cm/sec)
ComDaction Eauinnient
1
1.1 x 10"5
S
2
5.5 x 10"6
S
3
9.4 x 10"6
s
4
2.6 x 10"7
R
5
2.0 x 10"6
R
6
4.8 x 10"7
R
7
2.7 x 10"6
S
8
4.3 x 10"6
s
9
2.7 x 10"5
s
10
1.2 x 10"5
R
11
2.6 x 10"5
R
12
2.6 x 10"6
R
13
3.3 x 10"6
R
14
3.9 x 10"6
S
15
3.4 x 10"6
R
16
2.2 x 10"5
R
17
7.8 x 10"6
S
18
1.5 x 10"5
S
19
1.0 x 10"5
R
20
1.0 x 10"6
R
Average
8.5 x 10"6
Compaction achieved with
scraper or vibratory roller
Minimum
2.6 x 10"7
II
Maximum
2.7 x 10"5
II
II
Source: RMT 1996a
Note: S = Scraper
R = Vibratory Roller
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6.4.2.5
Lehigh Portland Cement Company CKD Pile - Metaline Falls, Washington
Overview
The Lehigh Portland Cement Company (Lehigh) CKD Pile is located southwest of the Town of
Metaline Falls, Washington. Lehigh operated a cement plant in Metaline Falls from 1952 to 1989,
when Lehigh sold its plant to the Lafarge Corporation. Use of the CKD disposal site ceased in
1989 when Lehigh sold its plant. Lehigh retained ownership of the CKD disposal site, which
comprises a parcel of about 13 acres (Dames & Moore, 1996). The pile is located about 360 feet
east of Sullivan Creek, a tributary of the Pend Oreille River. Prior to its closure in 1996 the
footprint of the pile comprised about 7.2 acres, its maximum thickness was estimated at about 75
feet and the total weight of CKD disposed in the pile was estimated at about 550,000 tons
(Dames & Moore, 1996).
Available Information on Properties of CKD - Metaline Falls. Washington
Reports available addressing physical properties of the CKD in the pile are summarized by EPA
(1997b) as follows:
• analysis of samples of the CKD from the pile indicate that the material is similar to
a non-plastic, silty soil;
• particle size analysis indicates the CKD contains approximately 80 to 90 percent
silt and fine sand;
• the moisture content of the CKD in the pile (prior to closure) is about 60 to 75
percent near the surface;
• the dry density of CKD ranges from 35 to 65 pcf;
• zones of higher moisture content within the pile are noted to have a greater degree
of plasticity; and
• the optimum moisture content is in the range of 23 to 50 percent.
CKD density, moisture content, and permeability data summarized by EPA (1997b) are presented
in Table 6-9. As shown in Table 6-9, the saturated hydraulic conductivity in two relatively
undisturbed CKD samples ranged from 1.7 x 10"4 to 1.2 x 10"5 cm/sec. CKD compacted to about
90 percent of Standard Proctor maximum dry density showed permeabilities ranging from 7.5 x
10"5 to 1.4 x 10"6 cm/sec.
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Table 6-9: CKD Density, Moisture Content and Laboratory Permeability Data
^ehigh CKD Pile, Metaline Falls, Washington
Test No.
Wet Density
(pcf)
Moisture
Content (%)
Permeability
(cm/sec)
1(U)
74.6
58.4
1.7 x 10"4
2 (U)
90.7
87.3
1.2 x 10"5
3(R)
94.3
59.3
7.5 x 10"5
4(R)
106.7
57.2
1.4 x 10"6
5(R)
100.6
53.9
2.2 x 10"6
6(R)
99.6
42.2
3.9 x 10"6
7(R)
101.7
46.2
4.5 x 10"6
Source: USEPA 1997b
Note: "U" denotes testing performed on a relatively undisturbed sampled.
"R" denotes testing performed on a remolded field bulk sample.
The EPA report (1997b) also summarizes information available on strength and compression
characteristics of the Metaline Falls CKD, as follows:
• Penetration data from split-tube sampling of the CKD pile indicate that the
physical strength of the material is variable and ranged from 1 to over 33 blows per
foot (blow counts corrected for Standard penetration Test analysis). Blow counts
of 4 to 9 per foot were most typical.
• The normal shear strength of the CKD material ranged over almost an order of
magnitude, from 25 to 200 kg/m2 (500 to 4,000 pounds/foot2).
• A cohesion of 30 kg/m2 (600 pounds/foot2) and friction angle of 25 degrees was
selected for slope stability analysis purposes in designing the CKD pile closure.
• Compression tests indicate that CKD is moderately compressible. Compression
index values of 0.25 and 0.4 were observed in the virgin compression portion of
the tests. Grading and capping of the CKD pile is estimated to result in somewhat
lower compression indices, on the order of 0.21 and 0.35.
Use of CKD as a Capping Material
In the planning for closure of the CKD pile, the use of compacted CKD as the barrier within the
capping system was considered based on cost. In subsequent review, compacted CKD was
rejected based principally on concerns about placement on steep slopes (USEPA, 1997b).
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Site Closure
The capping system designed and implemented in 1996 had as its principal element a geosynthetic
clay liner (GCL), overlain by a geocomposite drainage layer and a 3-foot layer of cover material
over the geocomposite drainage layer (USEPA, 1997b). Post closure monitoring is currently
underway.
6.4.3 Evaluation of Instances Where CKD Was Actually Used as a Cap or Liner Material
In Sections 6.4.1 and 6.4.2, the engineering properties of CKD that determine its effectiveness as
a liner or cap are identified, the engineering properties of CKD determined in the laboratory and
the field are summarized, and cases where CKD has been proposed or used as a liner or cap are
described.
In this section, the use of CKD as a liner or cap is evaluated in terms of its performance and
constructability based on cases described in Section 6.4.2. Use of CKD is compared with Subtitle
C and D liners and cap materials in Section 6.4.4 and the use of CKD material as an intermediate
or daily cover is evaluated in Section 6.4.5.
As described in Section 6.4.1, the principal performance criterion for CKD or any other material
used as a liner or cap at a landfill is its ability to serve as a barrier to precipitation (in a cap) or
leachate (in a liner). The permeability of the barrier is the primary measure of performance and a
number of laboratory and field studies are reported that provide information on the predicted and
actual permeability of compacted CKD.
6.4.3.1 Cases Where CKD Has Been Used
In the case studies reviewed, three locations were identified where CKD has been used as an
engineered component of a CKD landfill:
• capping the Lehigh Cementon CKD Landfill, Greene County, New York;
• capping the Lehigh Alsen CKD Landfill, Greene County, New York; and
• capping the Independent Cement Corporation CKD Landfill, Greene County, New
York.
These facilities were discussed earlier in Sections 6.4.2.1.1, 6.4.2.1.2, and 6.4.2.2. Design phase
and construction phase data on CKD permeability are summarized below.
Lehigh Cementon Site - Capping
In the design phase of this closure project, laboratory testing of CKD showed permeability in the
range of 1 x 10"8 cm/sec (see Table 6-1). NYSDEC requirements for the closure specified a
permeability of 1 x 10"5 cm/sec or less (NYSDEC, 1985). Field permeability tests conducted at
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fifteen (15) locations showed permeabilities in compacted CKD test plots with a median value of
about two orders of magnitude greater than the design phase laboratory permeability. The median
value for permeability, 3.2 x 10"6 cm/sec, conformed to NYSDEC requirements, with two samples
showing permeabilities slightly in excess of the 1 x 10"5 cm/sec permeability required (see Table 6-
1).
Lehigh Alsen Site - Capping
As shown in Table 6-1, during the design phase of closure, permeability studies showed a median
CKD permeability of 1.6 x 10"6 cm/sec, with a range of 7.7 x 10"7 cm/sec to 7 x 10"5 cm/sec. The
results of twenty-four (24) tests during construction showed a median value for CKD permeability
of 5 x 10"5 cm/sec, and a range of 2.7 x 10"6 cm/sec to 1.6 x 10"4 cm/sec. Compared to the design
phase median value, the construction phase values showed a permeability of more than one order
of magnitude greater. See Tables 6-1, 6-4, and 6-5.
Independent Cement Corporation - Capping
During the preconstruction phase, seventeen (17) samples of stockpiled CKD showed
permeability values in the range of 9 x 10"7 cm/sec to 1.7 x 10"4 cm/sec, with a median value of 2.5
x 10"5 cm/sec (see Table 6-1). The results of fifty-eight (58) CKD permeability tests conducted
during capping of part of the site in 1996 showed a range in permeability from 3.1 x 10"7 cm/sec
to 1.1 x 10"4 cm/sec and a median value of 2.1 x 10"5 cm/sec. These permeability values are in
general agreement with the preconstruction values and in general agreement with the values
attained at the Alsen site.
Summary - CKD Permeahilitv at Locations Where CKD Has Been Used as a Cap
At the three (3) locations where CKD has been used as a cap, testing of the CKD as placed in the
field shows median permeability values of 3.2 x 10"6 cm/sec (Cementon); 5 x 10"5 cm/sec (Alsen);
and 2.1 x 10"5 cm/sec (ICC). The minimum permeability noted in the results of 97 tests reported
is 3.1 x 10"7 cm/sec and the maximum is 1.6 x 10"4 cm/sec. For all 97 tests, the median value is
2.3 x 10"5 cm/sec and the average is 3.4 x 10"5 cm/sec.
Referring to Table 6-1, Entry Nos. 2 through 6, 8, 10, and 14, comprise 175 test results for CKD
permeability during construction, from test plots and/or from the pre-construction phase.
Considering all of these test results, the expected permeability of CKD would be as follows:
• Minimum: 2.6 x 10"8 cm/sec
• Maximum: 1.7 x 10"4 cm/sec
• Median: 1.2 x 10"5 cm/sec
• Average: 1.8 x 10"5 cm/sec
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6.4.3.2 Conclusions - Performance of CKD Used as a Liner or Cap
Data are available from a number of sources addressing the permeability of compacted CKD.
Data from testing prepared in the laboratory appear to understate the permeability of CKD
compared to the results of testing on test pads and samples during construction. Field testing has
shown some permeability values less than 1 x 10"7 cm/sec. However, in the test data reviewed, 50
percent of the field tests measured permeability in excess of 1.2 x 10"5 cm/sec.
Recently reported test results for test plots at the Medusa Facility in Charlevoix, Michigan (RMT,
1996b), suggest that median values in the range of 5 x 10"6 cm/sec may be attained using multiple
pass compaction techniques and other controls. Historical data show, however, that in general,
compacted CKD would be likely to show a permeability slightly in excess of 1 x 10"5 cm/sec when
placed in the field.
Stability studies of CKD show acceptable strength characteristics. Settlement studies show some
settlement expected and designs must consider this possibility in selection of slopes and
appurtenances that are expected to perform as designed for long periods of time.
The performance of CKD liners subject to leachate flow from above has not been studied in terms
of chemical stability. Studies by Ballivy et al. (1992) suggest that water permeating a CKD liner
may show elevated pH and some metals, not from the quality of water entering the liner, but from
the liner itself.
The double liner system recently proposed for the closure of CKD piles at the Medusa Plant in
Charlevoix, Michigan is of significant interest. In the design proposed, the new landfill will serve
as the cap for existing CKD piles, and will essentially be a piggyback landfill. At this location, a
performance value for CKD permeability of 1 x 10-7 cm/sec is established. However, this
performance has not yet been demonstrated (Per. Com. Polasek, 1997).
6.4.3.3 Constructability
As described in Section 6.4.2.1.2, a principal concern in the use of CKD as a cap are construction
problems that may result when compaction of the material on relatively steep slopes is required.
In the closure of the Lehigh Alsen CKD landfill, rupture of the surface of the cap was reported
when a dozer-pulled compactor traversed the slopes. Successive horizontal lifts were required to
remedy this condition. A similar concern was noted in the design of the Metaline Falls,
Washington closure, where steep slopes were contemplated. The condition of the existing waste
CKD (e.g. a thin crust, overlying moist material) was also reported. In the case of the Metaline
Falls closure, a geosynthetic membrane was ultimately selected as the barrier layer in the cap.
In general, the construction of a CKD liner or cap requires control of moisture content,
compaction, and density in an environment involving the use of heavy equipment and exposure to
varying conditions of temperature and precipitation. Results from small area test plots show
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substantial variations in permeability under relatively controlled conditions.
6.4.4 Comparison of CKD Liners and Caps to Subtitle D and Subtitle C Liners and Caps
For landfilled wastes subject to regulation under RCRA Subtitles D and C, detailed requirements
for liners and caps have been established. As a point of reference in EPA's evaluation of CKD,
Subtitle D and C liner and cap requirements are reviewed below.
New or laterally expanded municipal solid waste landfills (MSWLFs) that are designed and
constructed in accordance with RCRA Subtitle D and implementing regulations 40 CFR Part 258,
must have a composite bottom liner and leachate collection system.5 The bottom liner consists of
two components, an upper component with a minimum 30-mil flexible membrane liner (FML)6
and a lower component which is, at minimum, 60 cm (2 feet) of soil compacted to a hydraulic
conductivity (permeability) of no more than 1 x 10"7 centimeters per second (cm/sec). The
leachate collection system must be designed to maintain a depth of leachate less than 30 cm (12
inches) above the liner. At closure a final cover system is required to minimize infiltration of
precipitation into the landfilled waste and, as a minimum, must have a barrier layer with a
permeability less than or equal to the permeability of any bottom liner system or a permeability no
greater than 1 x 10"5 cm/sec, whichever is less. An earthen infiltration layer at least 18 inches
thick and an erosion layer of at least 6 inches must also be provided.
For RCRA Subtitle C landfills, constructed for the disposal of hazardous wastes in accordance
with 40 CFR Part 264, a double liner system is required. The top liner is a highly impermeable
layer such as a geomembrane with a leachate collection system above. The bottom liner consists
of two components, a top component such as a geomembrane and a bottom component
constructed of at least 91 cm (3 feet) of earth compacted to a permeability of 1 x 10"7 cm/sec or
less. Other components, such as leak detection systems, are also required. See 40 CFR 264.300.
At closure, a cover system must be provided that has a permeability less than or equal to any
bottom liner or natural subsoils present.
In order to construct a landfill liner in compliance with the Subtitle D and Subtitle C requirements,
a layer of soil (clay) is required to have a permeability of 1 x 10"7 cm/sec or less. The
requirements and challenges in achieving the required permeablity in a soil liner include ensuring
that a sufficient liner thickness is established, that compaction is performed in thin lifts, and that
bonding is assured between lifts.
All of these considerations are applicable to the use of CKD as a liner or cap. The principal
5 Alternative designs are acceptable if it is demonstrated that groundwater will not be significantly impacted.
See 40 CFR 258.40.
6 If the FML is high density polyethylene (HDPE) it must have a minimum thickness of 60-mil (one mile =
1/1,000 inches).
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concern in the comparison with RCRA Subpart D and Subpart C landfill liner requirements is
whether CKD can consistently be placed in the field to provide a permeablity of 1 x 10"7 cm/sec or
less. As described in Section 6.4.3.2, the current data do not demonstrate that a value of 1 x 10"7
cm/sec can be achieved consistently in CKD placed in the field. Field data from the Alsen CKD
landfill indicate that CKD can be compacted to achieve a permeability of 1 x 10"5 cm/sec or less
and can be used as a low permeability barrier in a landfill cover system. A low permeablity barrier
consisting of compacted CKD with a maximum permeability of 1 x 10"5 cm/sec may be used in a
final landfill cover system, if the bottom liner system and native materials under an existing landfill
have a permeability of 1 x 10"5 cm/sec or greater. Mixing fly ash with CKD may also improve
performance in terms of permeability.
6.4.5 Daily and Intermediate Landfill Covers Using CKD or CKD Based Material
The Subtitle D landfill regulations require that operators of municipal solid waste landfills cover
the disposed waste with 15 cm (6 inches) of earthen material at the end of each working day.
Intermediate cover of greater thickness may be required on landfill sections where filling is not
occurring. Alternatives to the use of earth for daily or intermediate cover of greater thickness
may be required on landfill sections where filling is not occurring. Alternatives to the use of earth
for daily or intermediate cover may be approved by regulatory authorities if the operator
demonstrates that such alternatives will control disease vectors, fires, odors, blowing litter, and
scavenging without presenting a threat to human health or the environment. CKD has been
approved for use as landfill cover material as described below.
Two CKD-based products have been identified for potential use as a daily or intermediate cover
for a CKD landfill. The Report to Congress (USEPA, 1993b) identifies a project known as N-
Viro Soil®, which is a mixture of CKD and sewage sludge, and notes its use as a cover method at
landfills. A product known as Posi-Shell®, also CKD-based, has also been used as a cover
material at landfills. As part of the evaluation of CKD as landfill liners and caps, N-Viro Soil®,
and Posi-Shell®, were briefly evaluated based on vendor information and available information.
The evaluation of these products is summarized below. No endorsement of nor lack of
endorsement of these products by EPA or its contractors should be implied and the evaluation is
limited to the information as stated herein.
6.4.5.1 N-Viro Soil®
Process Overview
The N-Viro Soil® process is a patented process used in the treatment of denatured municipal
wastewater treatment plant sludge. In the process, CKD is added to the sludge as an alkaline
reagent. Other possible alkaline reagents include lime kiln dust, lime, alkaline fly ash and other
residuals. CKD is used at most of the facilities.
The CKD is mixed with the sludge at dose rate of 30 to 65 percent by sludge cake weight. The
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pH is raised to 12 standard units from 1 to 3 days, the temperature is maintained at 52 to 62° C
for at least 12 hours and the solids content is raised above 50 percent for at least 12 hours. The
material is then windrowed for 3 to 7 days to further dry and improve handling characteristics.
The process is said to destroy all pathogens and is said to produce a material that meets federal
sludge concentration limits.
Physical Properties
N-Viro Soil® is a soil-like material that is highly permeable, workable under a wide range of
moisture conditions and has a high water retention capacity. Wet sieve analysis shows average
grain size distribution to be 40 percent aggregate greater than 2mm, 25 percent medium to coarse
sand (0.25 to 2mm) and 34 percent smaller than 0.25mm (Logan and Harrison, 1995).
Other physical property averages are reported as follows:
Solids:
Particle Density (mg/cm3):
Bulk Density (mg/cm3):
Porosity:
Permeability:
62 percent
1.96
0.59
69.9 percent
0.0278 cm/sec (uncompacted)
0.000915 cm/sec (compacted - ASTM D698)
Current Uses of N-Viro Soil®
In 1994, over 285,000 metric tons (300,000 tons) of N-Viro Soil® was used as a daily landfill
cover at municipal landfills including: Novato, CA; Easley, SC; Easte Hyde, UK; Greenville, SC;
Lexington, KY; Middlesex County, NJ; and Saugerties, NY. At these facilities, N-Viro Soil® is
used as an alternative to importing topsoil. According to vendor information, N-Viro Soil® could
also be used as a component in the final landfill cover, because the organics and nutrients in the
soil would facilitate the establishment of a stable vegetative cover.
N-Viro Soil® as a Landfill Cover
As noted above, N-Viro Soil® has been found to be suitable for use as an intermediate or daily
cover at several municipal solid waste landfills in the United States. Vendor information reports
that the free draining, high aggregate content, and low plasticity properties of N-Viro Soil® allow
it to be readily used under most conditions as an intermediate or daily cover at CKD landfills to
minimize fugitive dust and erosion hazards. It would also be suitable as a component in the final
cap design to support a vegetative cover. On rare occasions, if not properly drained, leachate
from the N-Viro Soil® could become septic, with anaerobic bacterial growth, and could emit foul
odors due to the high organic content of the CKD N-Viro Soil® mixture. Vendor information
indicates that the use of N-Viro Soil® in a landfill is not expected to adversely impact nearby
water resources because the N-Viro Soil® meets the federal limits for release of treated sludge,
and CKD contaminants that might migrate through the pile are likely to be adsorbed in the
organic-rich N-Viro Soil® and to have a reduced bioavailability. The School Of Medicine In New
Orleans conducted a lead bioavailability study on lead contaminated soils (i.e., soil collected at an
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inter city location, soil with 10% N-Viro Soil®, and soils with 10% other biosolids). This study
found that the bone lead concentration of rats that ingested the N-Viro Soil® was about 33%
lower than that found in rats which consumed the control soil (Heneghan, 1994). N-Viro Soil®'s
primary limitations at CKD landfills are its cost (unless the landfill is located near a N-Viro®
facility) and potential marginal improvement over using native soils at the site locality. In
addition, the N-Viro International Corporation has a policy against using CKD from cement
plants which burn hazardous waste.
6.4.5.2 Posi-Shell®
Posi-Shell® is a mixture of CKD, recycled paper pulp, and short recycled polyester fiber and
water. Various mixtures are available, adding cement in various proportions depending on needs.
The mixture is manufactured on-site using mixing machines, CKD, bagged fiber and cement. The
mixed Posi-Shell® material is then applied by pump spray to the areas to be covered. Application
is generally about V2 inch thick, but thicker applications are also possible.
Its uses include dust control and covers for landfills for daily and intermediate cover and covers
for waste disposal sites to control fugitive emissions.
Wet density is about 95 pcf at a 60 percent moisture, with dry density about 60 pcf. Densities
may vary with the proportions of fiber and cement that may be used. Hydraulic conductivity is
reported to be about 6 x 10"6 cm/sec. TCLP leaching tests show leachate within acceptable limits.
Posi-Shell® has been approved for use as a daily cover at a number of landfill locations. Its use as
an intermediate cover material has also been approved.
Posi-Shell® is currently being used as a cover at a landfill in the State of Rhode Island. At this
landfill, Posi-Shell® has been applied as part of management measures to control hydrogen sulfide
emissions. Preliminary reports show the use of Posi-Shell® at this location is effective as a
measure to control hydrogen sulfide emissions in conjunction with a landfill gas extraction system
also installed at the site.
6.4.6 Cost Evaluation
Because the instances of the use of CKD as a barrier material in a landfill are few, actual cost data
are sparse. Two sources of information were identified in the review of the cases described in
Section 6.4.3. The information identified and comparisons with other cost data are summarized
below.
6.4.6.1 Lafarge Facility - Alpena, Michigan
In a February 20, 1997, letter from Lafarge to the Michigan DEQ, a comparison of the costs of a
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CKD liner versus a geosynthetic clay liner (GCL) is provided (Lafarge, 1997b). In that letter, the
unit cost for a CKD barrier 24 inches thick is said to be $1.00 per cubic yard (cy). [Note: This
cost is said to be the cost for placement of the CKD by Lafarge as part of daily operations and
may not reflect the costs that may appear in a contract bid by a separate contractor.]
6.4.6.2 Medusa Facility - Charlevoix, Michigan
In the interim closure/landfill design plan at the Medusa facility described in Section 6.4.3, a
feasibility study of landfill alternatives is provided (RMT, 1996a). In the cost estimate portion of
the feasibility study, liner construction cost is estimated at $75,000 per acre. [Note: This
represents an estimated cost of about $7.70 per cy as compared to the Lafarge estimate of $1.00
per cubic yard. The costs included in these estimates may not be comparable.]
6.4.6.3 Recent Information on Construction Costs for Clay Liners
In April 1997, bids for placement of a 2-foot layer of clay, compacted to 1 x 10"7 cm/sec
permeability, at the Town of Lakeville, Massachusetts Sanitary Landfill, were received by the
Town of Lakeville Board of Health. Bids (for placement only—not supplying the clay) from ten
(10) contractors ranged from $3.50 to $10.00 per cy, and averaged $6.60 per cy.
Based on the Lakeville, Massachusetts bids, the estimates prepared for the Medusa facility appear
to include costs that may be experienced in placement of a CKD liner by an outside contractor.
6.4.6.4 Cement Kiln Dust Monofill Cost Model
As part of the development of the proposed regulations for CKD management, a Cement Kiln
Dust Monofill Cost Model was developed (ICF, 1995).
The unit cost for compacted CKD used in the model is $4.51/m3 (or about $3.50/cy), which is in
line with the low bid recently received for placement of clay at the Lakeville, Massachusetts
landfill, as described above.
6.4.6.5 Conclusions - Cost for Use of CKD as a Liner or Cap
Since CKD is already available at CKD landfills, the costs for its use as a liner or cap are those
involved with placement, compaction, and associated testing and quality control. Estimates of
costs associated with use of CKD as a liner or cap range from a low of $1.00/cy to a high of
$7.70/cy. Based on comparisons with earlier estimates for CKD placement and current estimates
of placement costs for clay liners, expected costs for construction of CKD liners or caps, in the
range of $3.50/cy to $7.70/cy, could be expected, with a nominal estimate of $5.00 to $6.00 per
cubic yard appropriate for rough estimates. Additional refinement of this estimate would be
required to ensure that the comparisons are based on comparable assumptions.
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6.4.7 Summary
Representatives of the cement industry have proposed the use of compacted CKD as liners and
caps at CKD landfills and compacted CKD has been proposed or used as a CKD liner or cap at
several locations in the United States. As part of the development of regulations for CKD, EPA
evaluated the use of CKD as landfill liners and caps, focusing on information for actual locations
where CKD has been used or proposed.
In the evaluation, the permeability of CKD, as placed in the field, is identified as the principal
physical characteristic controlling the effectiveness of CKD in providing an acceptable barrier to
the migration of precipitation into a CKD landfill (capping) and in providing an acceptable barrier
to leachate release into the subsurface beneath a CKD landfill (e.g. a landfill liner).
The evaluation first reviews and identifies the characteristics of soils and soil-like materials such
as CKD, which determine how they may perform as a barrier to the flow of liquids. Particle size,
particle size distribution, moisture, voids, and compaction are identified as the primary
determinants and standard tests used are described for subsequent reference in the description of
the engineering properties of CKD. The evaluation notes concerns that permeabilities of liners, as
actually placed in the field, may not be as low as predicated by laboratory tests, based on
experience in the use of clay liners.
Locations where CKD has either been proposed or used as liners or caps for CKD landfills are
described. These include:
• The Lehigh Cementon CKD landfill in Greene County, New York, where a 46 cm
(18-inch) compacted CKD layer was installed in 1988 as part of the cap during site
closure.
• The Lehigh Alsen CKD landfill in Green County, New York, where a 1.37 m (54-
inch) layer of compacted CKD was used in capping the site between June 1992
and June 1994.
• The Lehigh Alsen Quarry landfill in Greene County, New York, where a single
layer of compacted CKD, 46 cm (18-inch) thick, was proposed as a CKD landfill
liner and a similar layer of CKD was proposed as a cap.
• The Independent Cement Corporation CKD landfill in Greene County, New York,
which is undergoing phased closure using a 1.37 m (54-inch) thick compacted
CKD cap.
• The Lafarge Corporation CKD disposal facilities in Alpena, Michigan, where a
1.83 m (6 foot) layer of compacted CKD was proposed as part of the bottom liner
for a new landfill and a similar layer was proposed for its cap; and capping the
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existing disposal area with CKD (in part) was also proposed.
• The Medusa Cement Company CKD disposal facilities in Charlevoix, Michigan,
where a double liner of compacted CKD is proposed, each 91 cm (36-inch) thick,
as part of a new CKD landfill would serve as a cap for existing disposal areas.
• The Lehigh CKD disposal site in Metaline Falls, Washington, where CKD was
initially considered as part of the cap design for closure.
The evaluation tabulates the findings of studies conducted to determine the engineering properties
of CKD, focusing on laboratory and in-field permeability test results available from locations
where CKD has been proposed or used. Information from the Portland Cement Association is
also included in the tabulation.
Findings concerning the permeability of CKD include the following:
• Laboratory test results of CKD permeability may understate CKD permeability
when results are compared to permeability test results from CKD placed in the
field at actual locations.
• During capping of the Lehigh Cementon CKD site in New York, the median value
for CKD permeability was 3.2 x 10"6 cm/sec based on in-field tests.
• During capping of the Lehigh Alsen CKD site in New York, the median value of
permeability tests during construction was 5 x 10"5 cm/sec.
• During capping of part of the Independent Cement Corporation CKD site in New
York, the permeability test results showed a median value of 2.1 x 10"5 cm/sec.
• Ninety-seven (97) permeability test results are available for CKD placed as a cap at
the three New York sites (Cementon, Alsen, and Independent Cement). The
median permeability value for these ninety-seven tests is 2.3 x 10"5 cm/sec.
• Recent testing of CKD placed in test plots at the Medusa facility in Charlevoix,
Michigan, show a median permeability value of about 5 x 10"6 cm/sec in tests
where compaction was provided by 11 to 14 passes of tire compaction equipment
or 4 passes of a vibratory roller.
• In test plots constructed at the Larfarge facility in Alpena, Michigan, a median
value for CKD permeability of 2.4 x 10"6 cm/sec was shown in CKD placed by
scraper and concrete trucks. Cracking was observed in all test plots.
• In test plots constructed at the Ash Grove Cement Plant in Chanute, Kansas, a
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median value of CKD permeability of 2.3 x 10"5 cm/sec is shown in test results
where compaction equipment included a vibratory padfoot roller, a rubber tire
roller, and a vibratory drum roller.
• In 205 test results for CKD permeability during construction, from tests plots, and
from pre-construction data, the median value for CKD permeability is 1.0 x 10"5
cm/sec.
The evaluation finds that while testing has shown compacted CKD with permeabilities of 1 x 10"7
cm/sec or less, the current information shows permeabilities exceeding 1.0 x 10"5 cm/sec in 50
percent of the tests.
The EPA evaluation cites findings of design studies indicating that CKD has strength and stability
characteristics that are acceptable. Potential problems in constructing caps on CKD landfills when
compaction is required on steep slopes is noted. The need to consider long-term settlement in the
design of CKD landfills is also noted.
A brief comparison of CKD liners with liners required for Subtitle D and Subtitle C landfills
indicates that CKD liners would not be expected to consistently meet 1 x 10"7 cm/sec permeability
requirements, based on currently available information. In situations where existing landfills lack
a bottom liner and the permeability of the native geologic materials exceed 1 x 10"5 cm/sec,
compacted CKD may warrant consideration for use as a low permeability barrier in the final cover
system.
Approximate costs of using CKD in liners or caps are addressed in the final section of the
evaluation. Current cost estimates for compacted CKD to be placed at CKD landfills are available
from facilities in Charlevoix and Alpena, Michigan. Noting the potential that the estimates from
the Michigan facilities may not be comparable, recent bids for placement of a compacted clay liner
in Massachusetts and earlier cost modeling prepared by EPA, the evaluation concludes that costs
for CKD liners or caps may be in the range of about $5.00 to $6.00 per cubic yard ($6.50/m3 to
$7.80 m/3).
Observations based on the information reviewed include the following:
Following placement, substantial cracking has been observed as hydration occurs. Severe
cracking may compromise the performance of the CKD in achieving the permeability required to
effectively serve as a liner or cap at the landfill.
The addition of fly ash to CKD may improve its performance in achieving the permeability
required for service as a liner or cap.
The use of heavy equipment to achieve required compaction and resulting low permeability is
important during placement of CKD for service as a liner or cap. As noted above, steep slopes
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will hinder the use of heavy equipment at CKD landfills.
As in the case of soils, the degree of compaction and resulting density are also good indicators of
the permeability of CKD as placed in the field. Careful control of moisture, compaction, and
density are required to achieve the desired permeability of CKD to be used as landfill liners or
caps.
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Compton, Robert R., 1973. Manual of Field Geology. John Wiley and Son, Inc. New York
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with Supplement No. 1, Lehigh Portland Cement Company, Cementon, New York.
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Cementon, New York, Details, Notes and Specification," Drawing 994C-3, April, 1986.
Dames & Moore, 1996. Final Closure Plan for the Closure of the Cement Kiln Dust Pile,
Metaline Falls, Washington. Revised April 11, 1996.
Dunn Geoscience Engineering Co. (Dunn), 1992a. Revised Closure Report, Alsen Dust Disposal
Facility, Green County, New York. February, 1992.
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Dunn Geoscience Engineering Co. (Dunn), 1992b. Engineering Report and Application for a
Permit to Construct and Operate a Solid Waste Management Facility. March 31, 1992.
Gilbert/Commonwealth, Inc., 1994. Preliminary Application for Permit Modification for
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Reading Pennsylvania. June 27, 1994.
Heneghan, James B., Professor, Surgery & Physiology, School Of Medicine In New Orleans,
Louisiana State University Medical Center. Re: Final Report Lead Bioavailability of
Biosolid Amended Soils. September 29, 1994.
Hamilton, John, Facilities Manger, Bureau of Land Recycling & Waste Management,
Pennsylvania Department of Environmental Protection, Northcentral Region. March 19
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Cement Kiln Dust Monofill Cost Model. February 19, 1996.
Kircher, Richard, New York State Department of Environmental Conservation, May 23, 1997
(personal communication).
Lafarge, 1997a. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Lafarge Corporation - Alpena Plant, Project Progress Reports. January
28, 1997.
Lafarge, 1997b. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Comparison of GCL versus CKD CQA Liner. February 20, 1997.
Lafarge, 1997c. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Alternative Drainage Layer, Cell 1 Landfill Liner Construction. April 18,
1997.
Lafarge, 1996a. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Lafarge Corporation - Alpena Plant, Project Progress Reports. October
30, 1996.
Lafarge, 1996b. Letter from Mr. Hector Ybanez, Lafarge Corporation, to Mr. Thomas Polasek,
MDEQ. RE: Lafarge Corporation - Alpena Plant, Project Progress Report. October 22,
1996.
Lafarge, 1996c. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Lafarge Corporation - Alpena Plant CKD and Fly Ash Amended CKD Test
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Plots. October 24, 1996.
Lafarge, 1996d. Letter from Mr. Hector Ybanez, Lafarge Corporation to Mr. Thomas Polasek,
MDEQ. RE: Type III Landfill - Cell 1 Liner Alternatives. December 17, 1996.
Lamb, T. William, Whitman, Robert T., 1969. Soil Mechanics. John Wiley and Sons, Inc., New
York, 1969.
Logan, T.J. and B.J Harrison. 1995. "Physical Characteristics of Alkaline Stabilized Sewage
Sludge (N-Viro Soil) and Their Effects on Soil Physical Properties". In Journal of
Environmental Quality, Vol. 24, no 1. January-February 1995.
Michigan Department of Natural Resources (MDNR), 1995. Letter to Mr. John Stull and Mr.
John Cheony, Lafarge Corporation from Mr. Thomas Polasek, P.E., Michigan Department
of Natural Resources. RE: Lafarge Corporation, Interim Closure and Action Report.
March 8, 1995.
Michigan Department of Natural Resources (MDNR), 1994. State of Michigan, Site Specific
Designation of Inertness for Lafarge Corporation. August 9, 1994.
New York State Department of Environmental Conservation (NYSDEC), 1985. Letter from Mr.
Jeffrey Schmidt, New York State Department of Environmental Conservation, to Mr.
Dean Sandbrook, Lehigh Cement. December 4, 1985.
Polasek, Thomas, Michigan Department of Environmental Quality. April 1997 (personal
communication).
Stevens, Mark and Jason Fellon, Bureau of Land Recycling & Waste Management, Pennsylvania
Department of Environmental Protection, Northcentral Region, June 30, 1997 (personal
communication).
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Phase I Design Concept and Operating Plan. June 10, 1981.
Pennsylvania Power & Light Company (PP&LC), 1987. Montour Ash Storage Area No. 2,
Ground Water Assessment, Data Review. November 1987.
Pennsylvania Power & Light Company (PP&LC), 1997. Letter report from Jerome Texler,
Compliance Services Manager to Jim Diehl, PDEP. Montour Steam Electric Station, Ash
Area No. 3, Quarterly Ground Water Report. File 773187-05C. February 27, 1997.
Pirnie, 1997. Certification Report, Independent Cement Corporation, Catskill, New York.
Malcolm Pirnie, Inc., Draft, February, 1997.
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RMT, 1993. CKD Moisture Conditioning and Characterization Test Plot Documentation
Report, Lafarge Corporation, Alpena Plant. RMI, Inc. June 1993.
RMT, 1996a. Pile 6 and 9 Interim Response/Closure Plan and Landfill Design Plan, Medusa
Portland Cement Company, Charlevois, Michigan. RMT, Inc. December 1996.
RMT, 1996b. Hydrogeologic Investigation Summary Report, Medusa Cement Company,
Charlevoix, Michigan. RMT, Inc. February, 1996.
RMT, 1995. Final Closure, Maintenance and Monitoring Plan, Lafarge Corporation, Alpena,
Michigan. RMT, Inc. Volumes I and II, June, 1995.
RMT, 1994a. Interim Closure and Action Plan Report, Lafarge Corporation, Alpena, Michigan.
RMT, Inc. November, 1994.
RMT, 1994b. Type III Landfill Engineering Plans and Design Report, Lafarge Corporation,
Alpena, Michigan. RMT, Inc., December, 1994.
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Plan, Independent Cement Corporation, Catskill, New York. May 23, 1995.
Spectra, 1995. Lehigh Portland Cement Company, Alsen Dust Disposal Facility, Closure
Certification Report. Spectra Engineering, P.C., February, 1995.
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Todres, H., Mishulovich, A., and Ahmed, J., 1992. CKD Management: Permeability. Research
and Development Bulletin RD103T. Portland Cement Association, Skokie, Illinois.
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18, 1997.
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Chapter 7: Site Characterization, Ground Water Monitoring, and Corrective Action
EPA is proposing ground water monitoring and corrective action requirements for all facilities
that manage waste CKD in land-based management units to detect the presence of regulated
constituents in the ground water and allow for swift remediation of ground water problems. The
ground water monitoring and corrective action requirements proposed by the Agency are based
on requirements promulgated under Part 258 for MSWLFs. Using the approach provided under
Part 258 for MSWLFs will provide flexibility to facilities that manage CKD and to States in
selecting and implementing the remedy. This chapter describes the implementation considerations
for site characterization, ground water monitoring, and corrective action at CKDLF units.
7.1 Site Characterization
Prior to the design and construction of a CKD landfill and design and implementation of a ground
water monitoring program, it is necessary to characterize the subsurface conditions at the
proposed landfill location. This section discusses some of the technical requirements for
performing site characterization.
As discussed in Chapter 5, EPA is proposing special site characterization and certification
requirements for CKDLF units located in karst terrains. Section 7.1.1 addresses how to evaluate
whether a CKDLF unit is located in karst terrain. Technical considerations for the design and
implementation of a ground water monitoring system are described in Sections 7.2, and technical
and regulatory requirements for unit-specific corrective action are described in Section 7.3.
Meeting the ground water monitoring requirements for CKDLF units in karst terrains with a
significant component of conduit flow will be very difficult. The Agency strongly recommends
that owners and operators forego siting their facility above conduit-flow karst aquifers.
Environmental damage has been documented for at least nine CKD disposal sites where the
ground water systems had conduit-flow characteristics. The number of cement plants disposing
of CKD in mature and immature karst terrains were estimated at 5 and 51, respectively (see
Section 4.3). Under the proposed rule, owners or operators of new CKDLF units located in
potential karst terrain must perform site-specific evaluations to determine if conduit-flow karst
aquifers are present beneath the site. In addition, all facilities should conduct a hydrogeologic
investigations to properly design and implement a ground water monitoring program.
7.1.1 Characterizing Site Hydrogeology in Karst Terrain
Owners or operators of new and existing CKDLF units located in karst terrain must demonstrate
that engineering measures have been incorporated into the CKDLF unit's design to ensure that
the integrity of the CKDLF unit will not be disrupted. As an initial step the owner or operator
must gather site-specific information to determine whether or not the site is located in karst
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terrain and whether or not karst aquifers or formations underlie the site. Sites which are found to
be located in karst terrain must collect additional site-specific soil and ground water data for
designing the CKDLF unit (see Sections 7.1.2 and 7.1.3).
The facility should assume that karst conditions potentially are present if the site overlies rocks
which may be dissolved by water, including but not limited to limestone and dolomite formations.
If soluble rocks are present in the CKDLF unit vicinity, a qualified professional must review
available literature or conduct basin-wide field study and certify whether or not that the site is
located in karst terrain. At a minimum, the following data must be collected and evaluated in
order to determine whether a terrain is karstic:
• On-site and local geologic or geomorphologic features (as depicted in U.S. and
State Geological Survey reports, State and local regulatory agency reports, and
private reports; aerial photos and topographic maps to locate lineaments,
sinkholes, springs and to identify drainage patterns);
• On-site and local soil conditions (including review of Soil Conservation Services
reports and maps);
• On-site and local hydrology conditions (including identification of downgradient
springs and potential receptors and evaluation of the response of ground water
levels and springs to storm events); and
• Past and current human activities that may have altered topographic features and
ground water conditions, and thus mask evidence of karst features (aerial
photographs and previous land uses must be reviewed).
If a CKDLF unit is certified to be located in karst terrain, the notice of certification must be
submitted to the State Director. An additional investigation then is required to characterize karst
aquifers and/or other karstic features that may be present at the site. These site characterization
activities must include:
• An inventory to identify springs, wells, streams, caves and other karst features in
the site's ground water basin; and
• Characterization of the ground water flow rate and path from the CKDLF unit to
all potential intermediate sampling locations and to the spring(s) in the ground
water basin.
Other methods to determine whether karst features may be present in the site vicinity include:
• Detailed geologic field mapping to locate and verify the presence of additional
sinkholes, springs, caves, and other karst features not shown on topographic maps;
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• Quantifying ground water recharge/discharge relationships as determined by dye or
other suitable tracing techniques;
• Plotting the orientation and density of joints, local stratigraphic and lithologic
variations and subsurface relationships not readily discernible from the field
mapping; and
• Plotting of ground water levels or potentiometric surfaces on a map to determine
the relationship of the aquifer unit to other stratigraphic units.
During the course of conducting previous site characterization activities, hydraulic slug tests may
have been conducted in monitoring wells to facilitate calculation of ground water flow rates. In
karst areas, hydraulic conductivities measured by slug tests typically underestimate ground water
flow rates by several orders of magnitude relative to tracer dye studies and should be evaluated
with caution (Smith, 1997). Wells that were originally sited without consideration of conduit
flow should be used for monitoring only if dye tracing has first proven a connection between from
the CKDLF unit to each of the wells under varying flow conditions (USEPA, 1992).
Because the definition of karst is so broad, however, the Agency recognizes that some limestone
or other carbonate rock terrains may be suitable for siting a CKDLF unit. The Agency is
providing an opportunity for a demonstration by the CKDLF unit owner or operator to show that
subsidence will not adversely affect the CKDLF unit and that the site's hydrogeology can be
characterized, and ground water can be monitored effectively.
If the unit is located in karst terrain and springs are found in the ground water basin near the unit,
then a comprehensive karst ground water study must be conducted which includes a qualitative
tracer dye study. Because contaminant pathways in karst aquifers are often discrete and tortuous,
and identification of the uppermost aquifer and its ground water flow paths is a formidable task,
the Agency recommends that CKDLF operator avoid siting disposal units over karst aquifers with
demonstrated conduit flow characteristics. At a minimum, multiple quantitative tracer dye studies
and ground water modeling would be required to properly characterize the site and to optimize
detection of potential releases from the proposed CKDLF unit.
7.1.2 Data Required for Design of Ground Water Monitoring Systems in Karst Terrain
The ability to characterize a site's hydrogeology and monitor ground water effectively is vital for
the early detection of contaminant releases from any landfill unit. Under the ground water
monitoring standards being proposed for CKDLF units and summarized in Chapter 5, monitoring
wells are required to detect contaminant releases at a point of compliance in the uppermost
aquifer at a distance no more than 150 meters from the landfill unit boundary, on land owned by
the landfill owner. One upgradient and at least three downgradient monitoring wells are required
to determine, by comparing upgradient and downgradient water quality, whether releases, if any,
Draft: June 1998
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may be attributed to the landfill. Where releases are detected, appropriate corrective measures
must be implemented.
Ground water monitoring wells must be installed to monitor the relevant point of compliance that
ensures detection for ground water contamination in the uppermost aquifer. A site's
hydrogeology must be characterized to identify ground water flow pathways at the site and its
vicinity. In karst terrains, subsurface conduits are the primary pathways that contaminant releases
will follow. Identifying and intercepting these conduits with wells is a extremely formidable task.
Owners or operators of CKDLF units in karst terrain must define the direction and rate of ground
water flow, the depth to water, the configuration of the potentiometric surface of the uppermost
aquifer, and points of discharge (springs, surface water bodies, pumping wells, etc.) for the karst
ground water basin(s) that the facility might affect. In addition, because karst aquifers typically
show strong responses to rainfall events, a conceptual model must be developed which identifies
the optimum time for collecting ground water samples. Ground water and contaminants found in
ground water will have a higher propensity to migrate off-site during and immediately after peak
ground water flows associated with storms (Smith, 1997).
Quantitative tracer dye studies during base flow and storm flow events must be conducted to
properly place monitoring wells at appropriate locations and depths and ensure that monitoring
results are indicative of impacts to ground water that may be occurring. Because flow pathways
in karst aquifers are characteristically discrete, tortuous, and sensitive to storm events, repeated
studies using several types of tracer dyes with continuous monitoring of tracer dye concentration,
turbidity, and specific conductance may be warranted in order to characterize the ground water
flow system's response to storm events, to prepare chemographs, and to identify optimum
sampling times (Smith, 1997).
Even if the major flow pathways at a site are traced and the points of ground water discharge
(such as seeps and springs — which may be offsite) have been identified, the uppermost aquifer
must be monitored on site, at the point of compliance. EPA believes that monitoring seeps and
springs alone does not provide adequate protection of human health and the environment because
releases to the uppermost aquifer will not be detected until the contaminants have migrated off
site.
Even if accurate monitoring is demonstrable using tracer studies, the studies are not always
sufficiently reliable, unless the entire network of conduits can be characterized. In some cases, the
only instances of when flow rates and directions from a release point can be determined is after
contamination is detected and the damage to human health or the environment has occurred.
During storm events, contaminants in karst terrains may migrate off-site in matter of a few hours
or days where significant conduit flow is present. Accordingly, it would be essentially impossible
to demonstrate that corrective action could be performed under these conditions.
7.1.3 Data Required for Design of CKDLF Units in Karst Terrain
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If a facility can demonstrate that the ground water system beneath a CKDLF unit located in karst
terrain can be monitored in accordance with the proposed standards, then the facility must also
demonstrated that the CKDLF unit can be designed to control the effects of significant differential
settling, collapse, or puncture of the landfill liner due to the presence of karst.
Of particular concern are those karst areas where the karst is considered mature. As shown in
Table 2-3, of the 110 cement plant locations in the United States, 20 are estimated to be located
in mature karst areas where there is a potential for subsidence (e.g., sinkholes). Of these 20
locations, 5 currently dispose of CKD in on-site landfills. EPA believes, however, that special
consideration for the stability of foundation material is warranted in all karst areas because
surficial evidence of sinkholes may not be present. Relatively small subsurface voids may result in
sinkhole formation and the absence of large voids is insufficient evidence that sinkholes are not
likely to develop at a specific site.
To ensure that foundation conditions are suitable when locating CKD landfills in karst areas, EPA
believes that a site-specific characterization is required to include consideration of the potential
for the presence of sinkholes or sinkhole-like subsurface conditions. This characterization should
be conducted in concert with the delineation of ground-water flow pathways as described in this
section. EPA has described methods for use in the characterization of subsurface conditions in
karst areas. These methods include subsurface drilling, sinkhole monitoring, geophysical
techniques, and remote sensing (USEPA, 1993a). Sophisticated gravity and electromagnetic
geophysical surveys may be appropriate for determining potential sinkhole locations, the presence
of underground caverns, and the bedrock topography which may be substantially different from
the surface topography.
Karst terrains are often unstable due to the sudden formation of sinkholes as collapse of overlying
soil into void spaces occur. Most instances of serious subsidence in areas underlain by solutioned
limestone have accompanied or have followed substantial lowering of the ground-water table, and
most incidences of subsidence are induced by human activity such as operation of water supply
wells and quarry construction dewatering. Hydrographs of ground water levels and site
conditions near the CKDLF unit should be reviewed to evaluate if declining water levels could
trigger sinkholes beneath the CKDLF unit.
Methods to mitigate karst terrain problems include solutions such as the control of ground water
and surface water conditions to minimize the rate of dissolution within near-surface limestone. In
areas where development of karst topography is minor, loose soils overlying the limestone may be
excavated or heavily compacted to achieve the required stability. In areas where the karst voids
are relatively small and limited in extent, infilling of the voids with grout may be an option
(USEPA, 1993 a).
7.2 Ground Water Monitoring
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This section describes the technical considerations for implementing the ground water monitoring
requirements for CKDLF units.
7.2.1 Need for Ground Water Monitoring at CKDLF Units
In the RTC (USEPA, 1993b) and in subsequent investigations presented in the NODA (USEPA,
1994), the Regulatory Determination (60 FR 7366), and site-specific case studies and risk
modeling summarized in Chapter 2 of this background document, the Agency has documented
potential and actual impacts to ground water caused by releases to the subsurface from CKDLF
units. As demonstrated by the damage cases, various hazardous constituents listed in Appendix
VIII of 40 CFR Part 261 found in CKD have a high potential to migrate from the waste into the
environment, and pose unacceptable risks to human health and the environment via the ground
water pathways. The constituents of concern include antimony, arsenic, barium, beryllium,
cadmium, chromium, lead, mercury, nickel, selenium, silver, and thallium.
The number and severity of the damage cases and the potential for damages to recur provide the
basis for the Agency's need to develop standards and operating criteria to protect ground water
resources at CKDLF units. Releases of constituents of concern from CKDLF units can be
detected by installing ground water monitoring wells along ground water flowpaths hydraulically
downgradient of CKD disposal sites. Therefore, as part of these proposed standards, the Agency
is proposing requirements for ground water monitoring at CKDLF units. The Agency believes
that a properly designed ground water monitoring system at a CKDLF unit will provide a number
of benefits. Ground water monitoring will allow the owner/operator to:
• measure the effectiveness of the CKDLF unit design in preventing releases,
• detect releases quickly thus avoiding costly contamination and cleanup,
• determine the nature and extent of any contamination if it does occur, and
• assess the effectiveness of any implemented corrective action.
The proposed ground water controls are flexible and can be tailored to site-specific conditions.
EPA believes this approach avoids over regulation and provides adequate environmental
protection at a reasonable cost.
7.2.2 Implementation and Technical Considerations for Ground Water Monitoring
As described in Chapter 5 of this background document, the proposed technical requirements for
site characterization and ground water monitoring at CKD disposal units are based on those
already promulgated under 40 CFR Part 258 (for MSWLFs) and 40 CFR Part 264 (for hazardous
waste management units). In developing these standards, EPA also considered a draft proposal
submitted to the Agency from the cement industry entitled Cement Kiln Dust Management
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Practices (Portland Cement Association, 1995). The proposed requirements have been tailored
to address the characteristics of CKD and provide sufficient flexibility to allow effective
implementation by States.
Upon completion of the site characterization and design and construction of the CKDLF unit, the
Agency proposes that a ground water monitoring program be implemented. EPA's proposed
standards for ground water monitoring at CKD landfills include provisions for:
• ground water monitoring well design, and construction (see Section 7.2.2.1),
• ground water sampling and analysis (see Section 7.2.2.2),
• statistical analysis of ground water monitoring data (see Section 7.2.2.3),
• detection monitoring (see Section 7.2.2.4), and
• assessment monitoring (see Section 7.2.2.5)
7.2.2.1 Ground Water Monitoring Well Design And Construction
As discussed in Section 5.4.1, a ground water monitoring system must have a sufficient number of
wells strategically located to determine background ground water quality and the quality of
ground water passing the point of compliance. However, if deemed to be appropriate by the
State, a multi-unit ground water monitoring system, based on the requirements of a single-unit
ground water monitoring system, may be used where several CKDLF units are located within the
same facility.
Owners and operators of a CKDLF unit must ensure that:
• monitoring wells be cased to maintain the integrity of the well borehole;
• well casings be screened or perforated and, if necessary, packed with gravel or
sand to allow the collection of ground water samples; and
• monitoring wells be sealed to prevent contamination of ground water or collected
samples.
The design of the ground water monitoring system must be based on site-specific information.
Lithology and grain sizes of geologic formations drilled through should be used to determine
proper packing and sealant materials. In addition, the screen length for the interval to be
monitored should be determined from the stratigraphy of the site location.
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Monitoring well casing and screen materials may be constructed of any of several types of
materials, but should meet the following requirements:
• Monitoring well casing and screen materials should maintain their structural
integrity and durability in the environment in which they are used over their
operating, closure and post-closure life.
• Monitoring well casings and screens should be able to withstand the physical
forces acting upon them during and following their installation and use including
forces due to suspension in the borehole, grouting, development, purging,
pumping, and sampling and forces exerted on them by the surrounding geologic
materials.
• Monitoring well casing and screen materials should not chemically alter ground
water samples, especially with respect to the chemical constituents of concern, as a
result of any sorbing, desorbing, or leaching of analytes from the well casing or
screen into the sample being collected.
• Monitoring well casing and screen materials should be relatively easy to install into
the borehole during construction of the well.
For facilities located in karst terrain, EPA is also proposing that a ground water monitoring
strategy include, where necessary, seeps, springs, and caves which are the ultimate discharge
points of the karst ground water basin in which the facility is located. Monitoring wells are rarely
effective when used in karst terrains with conduit flow, and supplemental monitoring points (such
as seeps, springs, and cave springs) should be used in conjunction with point of compliance wells
to detect releases from the CKDLF unit.
Because more than half of all cement facilities in the USA are located above limestone formations
in potentially karstic terrains, there is an increased probability that ground water will experience
conduit flow beneath these sites. The Agency recognizes that designers of ground water
monitoring systems at CKDLF units in karst terrains face special challenges since contaminants
can potentially migrate long distances through open conduits with little attenuation, adsorption,
and dispersion occurring. Ground water flowpaths may also be more difficult to locate and may
require the use of dye tracer studies. In addition, the number and organization of drains in the
flooded or saturated part of the karst aquifer may vary over relatively short distances, thus
affecting the transmissivity values of the aquifer throughout the site. These considerations
highlight the need to conduct thorough site characterizations at CKDLF units before installing
ground water monitoring systems. Guidance on designing appropriate ground water monitoring
systems in karst terrains and in conducting dye tracer studies is available in RCRA Ground Water
Monitoring: Draft Technical Guidance (USEPA, 1992) and Ground-Water Monitoring in Karst
Terranes: Recommended Protocols and Implicit Assumptions (USEPA, 1989a).
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7.2.2.2
Ground Water Sampling and Analysis
Ground water sampling and analytical methods used must be able to provide accurate and precise
measurements of indicator chemical constituents and physical parameters over time. Similarly,
protocols should be developed to ensure that sample collection, preservation, shipment, and
storage is always performed in a consistent manner. These factors as well as chain-of-custody
control, quality control and quality assurance procedures are necessary to ensure the validity of
the results of the ground water monitoring program.
During detection monitoring, samples should be collected at least semiannually. The frequency of
sampling should be based on site-specific hydrogeologic conditions. Background characterization
should include at least four independent samples at each monitoring well during the first
semiannual round of sampling. More frequent sampling may be appropriate to evaluate seasonal
effects on ground water quality. Owners or operators of a CKDLF unit should select a sample
collection frequency that facilitates collection of a data set that is statistically independent of the
previous set. Guidance on the collection of statistically independent ground water samples in
provided in Statistical Analysis of Ground-Water Monitoring Data at RCRA Facilities - Interim
Final Guidance (USEPA, 1989b)
Water level elevations must be measured at all wells prior to sampling. Measurements should be
taken in a time frame that avoids changes that may occur due to barometric pressure changes,
significant infiltration events, or aquifer pumping. Water level measurement devices must be
decontaminated prior to use at each well to prevent cross-contamination at wells.
Well purging should be accomplished by using a pump to slowly remove ground water from the
well. Bailers should be avoided because of their "plunger" effect resulting in continual
development or overdevelopment of the well. Wells should be purged at or below their recovery
rate to prevent migration of water in the formation above the well screen. All purging equipment
must be decontaminated prior to use.
Sample collection equipment should be made of inert materials to preserve sample integrity. The
use of dedicated sample equipment for each monitoring well is recommended to prevent cross-
contamination problems arising from improper decontamination procedures. Further guidance on
ground water sampling methodology is provided in RCRA Ground Water Monitoring: Draft
Technical Guidance (USEPA, 1992) and Ground-Water Monitoring in Karst Terranes:
Recommended Protocols and Implicit Assumptions (USEPA, 1989a).
7.2.2.3 Statistical Analysis of Ground Water Monitoring Data
The proposed rule for CKD requires the owner or operator of a CKDLF unit to determine
whether or not there is a statistically significant increase over background levels for each
parameter and constituent the owner or operator is required to monitor for under the appropriate
program (i.e., detection monitoring, assessment monitoring, or corrective action). The owner or
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operator is required to make these statistical determinations each time he or she assesses ground
water quality. In making this comparison, the owner or operator must apply a statistical
procedure specified in the proposed rule and make a determination of whether there has been a
statistically significant increase or decrease over background within a reasonable time period, set
by the State, after completing sampling.
In deciding which statistical test is appropriate, the owner or operator will need to consider the
theoretical properties of the test, the characteristics of the data, and site-specific conditions such
as the hydrogeology and the fate and transport characteristics of the potential contaminants. The
owner or operator must also ensure the selected test(s) meets the performance standards
established for statistical methods. Guidance on choosing appropriate statistical methods can be
found in Statistical Analysis of Ground-Water Monitoring Data at RCRA Facilities - Interim
Final Guidance (USEPA, 1989b) and in Statistical Analysis of Ground-Water Monitoring Data
at RCRA Facilities - Addendum to Interim Final Guidance (USEPA, 1992)1. EPA also offers
software, entitled the Ground-Water Information Tracking System (GRITS) with Statistical
Analysis Capability, GRITS STA T Version 5.0.2
7.2.2.4 Detection Monitoring
At least four independent samples from each background and downgradient well must be
collected and analyzed during the first semiannual sampling event. This is required because
almost all statistical procedures are based on the assumption that samples are independent of each
other and therefore reflect the true range of natural variability in ground water. Replicate samples
are not considered to be statistically independent measurements. The detection monitoring
program must include monitoring for pH, conductivity, total dissolved solids, potassium, chloride,
sodium, and sulfate.
To account for seasonal differences, it may be necessary to collect the independent samples over a
range of time. The sampling interval chosen must ensure that sampling is being done on different
volumes of ground water. This may be achieved by determining the velocity of ground water at
the site using site data for effective porosity, hydraulic conductivity, and hydraulic gradient.
Additional information on establishing the sampling interval can be obtained from Statistical
Analysis of Ground-Water Monitoring Data at RCRA Facilities - Interim Final Guidance
(USEPA, 1989b). During each subsequent sampling event, the same requirements will apply
except that only one sample must be collected and analyzed from each background and
downgradient well.
1 EPA's guidance documents on the statistical analysis of ground water monitoring data currently are being
updated into a unified guidance document. The draft Unified Guidance is in peer review as of 3/18/98. Contact Hugh
Davis, OSW PSPD.
2 GRITS/STAT is available for free on EPA's World Wide Web site at:
http://www.epa.gov/epaoswer/hazwaste/ca/gritsstat/gritsstat.htm
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If statistical analyses show that downgradient monitoring points have a statistically significant
increase over background for one or more indicator parameters, the owner or operator must (a)
note the finding, identify the indicator parameter(s) in the operating record, and inform the State
of the notice in the operating record within 14 days, and (b) establish an assessment monitoring
program.
If an owner or operator can successfully demonstrate that the statistically significant increase is
the result of sampling error, analysis, statistical evaluation, or natural variation in ground water
quality, this demonstration must be certified by a qualified ground water scientist or approved by
the State and placed in the operating record. The owner or operator may then continue with a
detection monitoring program. If the owner or operator cannot file a successful demonstration
within 90 days, an assessment monitoring program must be initiated.
7.2.2.5 Assessment Monitoring
During an assessment monitoring program, at least one sample must be collected and analyzed
from each downgradient well during each sampling event. If assessment monitoring confirms the
detection of any of the release parameters specific in the rule (see Table 5-3 in this background
document), at least four samples must be collected from each background and downgradient well
and analyzed to determine background concentrations for that constituent. In addition, within 14
days of the detection, the owner or operator must place a notice in the operating record
identifying the detected indicator parameter(s) and notify the State that the notice has been placed
in the operating record.
If for two consecutive sampling events the concentrations of all assessment monitoring parameters
identified in Table 5-3 are shown to be at or below background values using the statistical
procedures in Section 7.2.3, the owner or operator shall notify the State and resume detection
monitoring. If, based upon the results of statistical tests, assessment monitoring parameter
concentrations are above background concentrations but below ground water protection
standards (see Section 5.4.5), assessment monitoring must be continued. If the concentrations of
any assessment monitoring parameters are detected at statistically significant levels above the
ground water protection standards established in Section 5.4.5 in any sampling event, the owner
or operator must, within 14 days of the finding:
• place a notice in the operating record identifying the indicator parameter(s)
exceeding the ground water protection standards,
• inform the State and appropriate local government officials that the notice has been
placed in the operating record,
• install additional monitoring wells to characterize the nature and extent of the
release,
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• install and sample at least one additional monitoring well at the facility boundary
along the direction of contaminant migration,
• notify land owners or residents on land directly above the contaminant plume of
the off-site contaminant migration, and
• begin an assessment of corrective measures within 90 days.
In the event that an owner or operator can successfully demonstrate that a source other than the
CKDLF unit caused the contamination or that the statistically significant increase is the result of
sampling error, analysis, statistical evaluation, or natural variation in ground water quality, this
demonstration must be certified by a qualified ground water scientist or approved by the State and
placed in the operating record. The owner or operator may then continue the assessment
monitoring program as specified in this section. Detection monitoring may be resumed if
indicator parameters are at or below background concentrations. If the owner or operator cannot
file a successful demonstration, the assessment monitoring program must continue and an
assessment of corrective actions be initiated.
The Agency is proposing a ground water protection standard to be the MCL (if available) or the
background concentration if background is greater than the MCL. If an MCL has not been
established for a constituent, the background concentration will be used as the ground water
protection standard. Available MCL values for constituents of concern are listed in Table 5-3,
and site-specific background concentrations are obtained by sampling hydraulically up-gradient
wells as discussed in Section 5.4.2.
7.3 Corrective Action
The proposed rule addressing CKD requires corrective action at active CKDLF units that exhibit
a statistically significant exceedance of ground water protection standards. The proposed rules
for corrective action are similar to corrective action requirements for municipal solid waste
landfills (MSWLF), and give owners and operators lead responsibility for initiating, planning, and
implementing remedial activities under state supervision. The goals of corrective action at active
CKDLF units are to (1) address existing releases, and (2) contain possible future releases before
environmental damages or health risks occur.
EPA is proposing corrective action for CKDLFs based upon empirical data and a series of risk
modeling studies that demonstrate significant risks to human health and the environment from
releases of CKD constituents into the environment. Existing regulatory authorities have led to
effective cleanups for some units. However, implementation of cleanups varies significantly from
state to state, and EPA believes there is a general lack of consistent regulations to address
releases of CKD constituents in a timely manner.
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CKD cleanups under existing authorities have shown that karst terrain, fractured bedrock, and
other site-specific factors can pose significant challenges to effective remediation. Because of
these challenges, the proposed regulations provide owners and operators with flexibility in
selecting appropriate remedies and remedial schedules. In addition, the regulations include a
practicability determination procedure to allow alternate response strategies when ground water
protection standards can not be attained with available technologies.
7.3.1 Need for Regulation and Regulatory Options Considered
As described in Section 2.1, EPA has documented at least 16 cases of damage to surface water
and/or ground water resulting from existing CKD management practices. In addition, the Agency
estimates that about 80 percent of the cement plants in the U.S. are located in areas with karst
terrain or fractured bedrock, where there is an increased risk to ground water from CKD disposal
(See Table 2-3 in Section 2 of this background document). Based on these concerns, EPA's CKD
regulatory determination (60 FR 7366) concluded that additional environmental controls are
warranted to address "the existence of damages to ground water and air that are persistent and
continuing, and for which no requirements exist to address the risks posed via these pathways."
The proposed corrective action requirements for CKDLFs are based on RCRA Subtitle D
corrective action requirements for MSWLFs. The proposal also is similar to Subpart F (rather
than Subpart S) corrective action requirements under RCRA Subtitle C in that remedial responses
are directed at releases from CKDLFs, rather than all potential sources at the facility. A
comparison of selected features of these various approaches is provided in Table 7-1.
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Table 7-1. Comparison of Corrective Action Programs
Subtitle C
Subtitle D
Proposed Rule for CKD
Regulated
Units (40 CFR
264 Subpart
F)
SWMUs
(Proposed 40
CFR 264 Subpart
S)
MSWLF
CKDLFs
containing waste-
derived and
characteristically
hazardous CKD
All other
CKDLF Units
Affected Media
Ground Water
All Media
Ground Water
All Media
Ground Water
Facility-wide or
unit-specific
corrective action
required?
Unit-specific
Facility-wide
Unit-specific
Same as
Subtitle C
Unit-specific
Point of
compliance
(POC)
Hydraulically
down gradient
limit of the
waste
management
area
Unit and medium-
specific (based on
migration and
exposure
potential)
Up to 150
meters
downgradient of
unit boundary
Same as
Subtitle C
Up to 150
meters
downgradient
of unit
boundary
"Trigger" for
Corrective
Action
GWPS
exceeded at or
beyond POC
Media-specific
(health and
environmentally -
based levels)
GWPS exceeded
at or beyond
POC
Same as
Subtitle C
GWPS
exceeded at or
beyond POC
Cleanup
Standard
GWPS or
cleanup level
specified in
permit
Concentrations in
GW, SW, air, or
soil that provide
long-term
protection of HHE
GWPS (i.e.,
MCL, alternate
compliance
limit, or
background)
Same as
Subtitle C
GWPS (i.e.,
MCL, or
background)
GWPS = ground water protection standard
POC = point of compliance
SWMU = solid waste management unit
HHE = human health and the environment
MSWLF = municipal solid waste landfill
CKDLF = cement kiln dust landfill
GW =ground water
SW = surface water
As EPA has demonstrated in the proposed rule, CKD meets the hazardous waste listing criteria,
and EPA considered subjecting CKDLFs to the Subpart F corrective action requirements (40 CFR
264.90-264.101). However, the proposed corrective action approach based on Subtitle D
provides environmental protection equivalent to Subpart F with less regulatory burden and more
flexibility for owners and operators. For example, [insert example of burden reduction estimate
when available]. Further, the Agency believes that existing state laws and federal imminent
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hazard authorities under Section 7003 of RCRA and Section 106 of CERCLA should be adequate
to address any genuine threats to human health and the environment.
In addition, EPA evaluated whether deferral to existing state remedial authorities would be an
acceptable alternative to new corrective action rules for CKDLFs. As described in Chapter 2,
EPA determined that existing state authorities do not correct contaminant releases from CKDLFs
adequately or uniformly. Therefore, national corrective action standards are warranted.
EPA's approach to corrective action for CKDLFs is consistent with lessons learned from sites
where remedial activities have been performed. In particular, remediation of some CKDLFs has
been complicated by their large size, common proximity to wetlands or other surface waters, and
frequent siting on karst terrain or fractured geologic media. These complications necessitate a
flexible remedy selection procedure suited to site-specific conditions. Also, remedy selection and
implementation must be adaptive to difficulties encountered and the limitations of available
remedial technologies.
Because site-specific flexibility is needed, the proposed corrective action rules do not prescribe
extensive remedy design criteria (e.g., cap materials), but provide performance-based standards
and evaluation criteria to guide owners and operators in developing and implementing remedial
programs. This approach gives CKDLF owners and operators flexibility to select remedies
appropriate to site-specific conditions, with minimal direction from EPA or state regulators.
7.3.2 Implementation and Technical Considerations for Corrective Action
EPA expects that remedial activities implemented under CKD corrective action will be similar to
remedies implemented under existing authorities, except that no corrective action is required for
inactive CKDLFs (i.e., units not accepting CKD waste after the effective date of the rule.)
Although the proposed CKD rule will not significantly increase the stringency of remedies, it is
likely to cause additional cleanups to occur in the event of a release. Additional cleanups are
expected because of the financial assurance requirements for corrective action, closures, and post-
closure care in the proposed rule, and the provision for federal enforcement if CKD is not
managed in compliance with the proposed standards. In addition, the proposed CKD rule will
support more timely implementation of remedies at CKDLF where corrective action is needed.
The primary goal of CKD remedies under existing authorities has been to control leachate
contamination of ground water and/or surface water. As discussed in Section 2.1.2, almost all
existing CKDLFs were constructed without liner systems sufficient to protect ground water.
Many of the CKDLFs are located in abandoned quarries, adjacent to surface waters, or in other
settings where CKD may come into direct contact with ground water or surface water.
CKDLF remedies generally consist of in-place source control and ground water remediation.
Source control usually includes placing a clay or synthetic cap over the landfill, and may also
include slurry walls, interceptor trenches, drain systems, or run-on/run-off controls. Remediation
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of contaminated ground water has been performed by installing recovery wells or trenches to
intercept contaminant plumes. Ground water remediation is complicated at many CKDLF sites by
karst aquifers or fractured geologic media. High hydraulic conductivities are frequently
encountered in both karst aquifers and fractured geologic media, and these conditions may require
treatment and removal of large quantities of contaminated ground water during site remediation.
For example, at the Holnam facility in Mason City, IA, a drain system and ground-water
extraction wells were required to collect runoff and ground-water inflow and prevent migration of
contaminated ground water from the quarry in which CKD was disposed (see Section 2.1).
In-place remedies have been favored for CKDLFs, because of large waste volumes and the
difficulty of handling wet CKD. This explains why none of the source control remedies
implemented at damage case sites has included retrofitting landfills with liners. For the same
reasons, it is uncommon for CKD to be excavated for off-site treatment or disposal. An
exception is the Portland Cement Company site in Salt Lake City, Utah, which is currently being
remediated under CERCLA authority. The heavily urbanized setting of this site was a major
reason for removing CKD waste materials from the site. At least 750,000 tons of CKD and
CKD-contaminated debris have been shipped to an off-site RCRA Subtitle D landfill, and 109
tons of chromium-contaminated brick have been removed to a RCRA Subtitle C landfill (USEPA,
1997).
The corrective action provisions of the proposed CKD rule will allow remedy selection to
continue on a case-by-case basis, with recognition of site-specific factors such as existing
environmental controls, potential risks, and hydrogeological conditions. EPA believes this
approach will produce swift and effective cleanups, yet provide flexibility for the inherent
difficulties (e.g., karst terrain, large waste volumes) of remediating many CKDLFs. The
remainder of Section 7.3 describes the three steps in the proposed CKD corrective action
program: assessment of corrective measures, remedy selection, and remedy implementation.
7.3.2.1 Assessment of Corrective Measures
Under the proposed CKD rule, the corrective action process is initiated by owners or operators of
CKDLFs within 90 days of detecting a hazardous constituent (listed in Appendix VIII of 40 CFR
Part 261) during assessment monitoring at a statistically significant level exceeding the ground-
water protection standard. The objective of this step is to identify and analyze potential remedies
and to discuss them with interested and potentially affected parties. The assessment of corrective
measures addresses at least the following:
(1) The performance, reliability, ease of implementation, and potential impacts of
appropriate potential remedies, including safety impacts, cross-media impacts, and
control of exposure to any residual contamination;
(2) The time required to begin and complete the remedy;
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(3) The costs of remedy implementation; and
(4) The institutional requirements such as State or local permit requirements or other
environmental or public health requirements that may substantially affect
implementation of the remedy(s).
The CKDLF owner or operator must complete the assessment of corrective measures within a
reasonable period of time and continue monitoring in accordance with the assessment monitoring
program while the assessment of corrective measures is underway. In addition, the CKDLF
owner or operator must hold a public meeting to discuss the results of the assessment of
corrective measures before proceeding to remedy selection.
7.3.2.2 Selection of Remedy
The proposed remedy selection process is performed by the CKDLF owner operator based on the
results of the assessment of corrective measures, public input, and remedy selection standards
specified in the proposed rule. Within 14 days of completing a remedy selection report, the
CKDLF owner or operator must notify the State Director and describe how the remedy meets the
required standards.
Remedy selection standards for CKDLFs are essentially the same as remedy selection for
MSWLFs. Specifically, the remedies must meet the following four standards:
(1) Be protective of human health and the environment;
(2) Attain the ground water protection standards (see Section 5.4.5);
(3) Control the source(s) of releases so as to reduce or eliminate, to the maximum
extent practicable, further releases of selected Appendix VIII constituents into the
environment that may pose a threat to human health or the environment; and
(4) Comply with standards for management of wastes (i.e., protective of human health
and the environment and fulfills applicable RCRA requirements).
In addition, the remedy selection must take these factors into consideration:
(1) Long- and short-term remedy effectiveness and protectiveness;
(2) Source control effectiveness;
(3) Ease or difficulty of implementation;
(4) Technical and economic practicability; and
(5) Community concerns.
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The remedy selection provisions of the proposed CKD rule give owners or operators flexibility to
schedule the initiation and completion of remedial activities. However, the proposed remedy
must include a schedule that requires initiation of remedial activities within a reasonable amount
of time.
7.3.2.3 Implementation of Remedies
The proposed rules for implementing corrective action at CKDLFs define when and how remedial
actions are determined to be complete, and guide owners or operators who are unable to comply
with remedial standards.
CKDLF owners and operators must implement a corrective action ground water monitoring
program that will measure the effectiveness of the remedy in attaining the ground water
protection standards. Remediation is complete when ground water protection standards are met
(based on statistical procedures) for three consecutive years at all points within the contaminant
plume that lie beyond the ground water monitoring well and spring system. The number and
placement of wells for corrective action monitoring must meet the minimum requirements of the
assessment monitoring program.
EPA recognizes that some owners and operators of CKDLFs may not be able to meet the
standards for completing corrective action. In particular, ground water recovery systems may
have limited effectiveness at sites with non-Darcy or conduit ground water flow (e.g., sites
located in areas with karst aquifers or highly fractured geologic media). In such cases, the
proposed rules include a practicability determination process that allows owners and operators to
implement alternate remedies with state approval. EPA considers this flexible approach a
necessity, because 79 of the 110 cement plants in the U.S. are estimated to be located in areas
characterized by karst hydrogeology. An additional 9 cement plants are located in non-karst areas
with moderate to high potential for non-Darcy conduit ground water flow due to fractured
bedrock aquifers. In all, about 80 percent of the cement plants in the U.S. are located in areas
that potentially have non-Darcy ground water systems.
At some CKDLFs where damage has occurred, interim measures have been required and
implemented to control continuing releases before the initiation of full-scale remedies. For
example, Ash Grove Cement (Chanute, KS) instituted immediate control measures including
surface regrading and interim trench pumping after leachate discharges were found flowing into a
tributary to Village Creek. National Gypsum Company implemented interim controls to prevent
further erosion and deposition of contaminants into Lake Huron. Consistent with these examples,
the proposed CKD corrective action rules require interim measures as necessary to protect human
health and the environment.
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7.3.3 Applicability of Corrective Action Regulations
7.3.3.1 Active Units
The proposed CKD rule lists CKD that is disposed after 90 days following publication of the final
rule as a hazardous waste unless it qualifies for a conditional exemption from RCRA Subtitle C
regulations as a result of management in accordance with specified requirements, including design
and operating standards and corrective action requirements. However, if the CKD is derived
from burning hazardous waste and the CKD exhibits a hazardous waste characteristic, then it can
not be exempt from the RCRA Subtitle C requirements.
The proposed corrective action standards apply to both new units and to existing units that
receive CKD waste after the effective date of the rule and are expanded laterally or vertically.
EPA anticipates that, with few exceptions, existing CKDLF units that are actively managed after
the effective date of the rule will be required to perform corrective actions, as necessary,
according to the methodology summarized in Section 7.3.2. New or existing CKDLF units, or
lateral expansions, that receive less then 10 tons of CKD per week, based on an annual average,
are exempt from the design criteria, ground water monitoring, and corrective action provisions of
the proposed rule, as long is there is no evidence of ground water contamination.
For listed CKD that is not managed in accordance with the specified requirements in the proposed
rule, additional RCRA Subtitle C requirements are also specified (i.e., a RCRA hazardous waste
permit would be required under 40 CFR Part 270). However, these additional requirements
would be specific to CKDLFs in use after the effective date of the rule and do not include facility-
wide corrective action requirements.
7.3.3.2 Inactive Units
The proposed corrective action provisions do not apply to CKDLFs that are not actively managed
after 90 days following publication of the final regulations. Existing state and federal (e.g.,
CERCLA) authorities will continue to govern cleanups at closed or inactive CKDLFs. Closed or
inactive CKDLFs at facilities that are subject to full RCRA Subtitle C requirements (due to
treatment, storage, or disposal of characteristically hazardous CKD or other activities that require
a RCRA Subtitle C permit, such as hazardous waste treatment) are subject to the corrective
action requirements of Subtitle C, including 40 CFR 264.90, 40 CFR 264.101, and Subpart S of
40 CFR 264.
Based on a screening-level analysis, the Agency estimates that at the close of 1995 there were
approximately 740 inactive CKD piles at the 110 U.S. cement plants that are currently (i.e., as of
1998) active. The Agency further estimates that approximately 90 million metric tons of CKD are
stored in these inactive piles. These estimates were compiled using data from the 1974, 1990, and
1993 editions of the Portland Cement Association's Plant Information Summary and PCA's 1991
PCA Cement Kiln Dust Survey. A explanation of the methodology used to prepare these
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estimates is provided in SAIC (1996). The five states with the greatest number of inactive CKD
piles at active facilities are presented in Table 7-2.
Table 7-2.
Five States with the Estimated Greatest Number of Inactive CKD Piles at Active Facilities
State
Estimated Number of Inactive CKD Piles
Pennsylvania
118
California
87
Texas
43
Illinois
39
South Carolina
35
7.3.3.3 Waste-Derived CKD
The proposed corrective action provisions are not applicable to CKD that exhibits a characteristic
of a hazardous waste and is waste-derived (i.e., generated using hazardous waste as fuel).
According, the proposed rule essentially maintains in place the rules for CKD from hazardous
waste burners that exist currently under 40 CFR, Part 266.
7.3.4 Benefits of Corrective Action
The proposed corrective action standards for CKD will protect the public from human health risk
and prevent environmental damage resulting from current CKD disposal practices. EPA believes
that the proposed corrective action standards are fully protective of human health and the
environment while avoiding unnecessary regulatory burden and cost.
Although some releases from CKDLFs have been remediated successfully under existing
authorities, there are a number of CKDLFs with known damages at which only limited or no
remedial action has been performed. The proposed corrective action provisions will cause some
of these CKDLFs to be cleaned up (if they remain active after the effective date) and will prevent
significant environmental damages at CKDLFs where future releases occur. Additional benefits of
EPA's proposed approach to corrective action include:
• Flexibility for owners and operators to select appropriate remedies and remedial
schedules;
• Additional reduction of direct contact and inhalation exposures to CKD and its
constituents resulting from ground water source control remedies; and
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Improved compliance with state and federal air and water quality standards and
goals.
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References
Portland Cement Association, 1995. Cement Kiln Dust Management Practices. Draft Report.
16p.
SAIC, 1996. Memorandum from Jack Mozingo, SAIC to Bill Schoenborn, EPA. EPA Contract
68-W4-0030, WA105, Task 7, QRT 4. June 4, 1996.
Smith, J.H., 1997. "Regulatory Definition of Karst Terrane and Groundwater Assessment and
Sampling Guidelines for Karst Aquifers, Draft Final Rule for Cement Kiln Dust Landfills".
Memorandum from James Smith, Environmental Scientist, RCRA Programs Branch, EPA
Region IV, to William Schoenborn, Environmental Scientist, Municipal and Industrial
Solid Waste Division. November 10, 1997.
USEPA, 1997. CKD Waste Releases and Environmental Effects Summary: Portland Cement
Superfund Site Salt Lake City, Utah. Office of Solid Waste (5302W), 2800 Crystal City
Drive, Crystal City, VA 20202. EPA Contract No. 68-W4-0030. March 1997.
USEPA, 1994. Notice of Data Availability, Human Health and Environmental Risk Assessment
in Support of the Report to Congress on Cement Kiln Dust. EPA Office of Solid Waste.
August 31, 1994, Revised per Federal Register Notice of October 11, 1994.
USEPA, 1993a. Report to Congress on Cement Kiln Dust, Volume II Methods and Findings.
EPA Office of Solid Waste. December 1993.
USEPA, 1993b. Solid Waste Disposal Facility Criteria, 40 CFR Part 258, Technical Manual.
EPA Office of Solid Waste. November 1993.
USEPA, 1992. RCRA Ground-Water Monitoring: Draft Technical Guidance. EPA Office of
Solid Waste. EPA/530-R-93-001. November 1992.
USEPA, 1989a. Ground-Water Monitoring in Karst Terranes Recommended Protocols &
Implicit Assumptions. Environmental Monitoring Systems Laboratory. EPA/600/X-
89/050
U SEP A, 1989b. Statistical Analysis of Ground-Water Monitoring Data at RCRA Facilities
(Interim Final Guidance) (NTIS No. PB89-151047) and Addendum to Interim Final
Guidance (July 1992) and Outline of Statistical Training Course, Office of Solid Waste,
Washington, DC (EPA 530/R-93-003).
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