Comment Summary and Response Document

Hazardous and Solid Waste Management System;

Identification and Listing of Special Wastes; Disposal of 

Coal Combustion Residuals from Electric Utilities; 

Proposed Rule

(Docket # EPA-HQ-RCRA-2009-0640)

Volume 5: Design Criteria: Liners

December 2014
1

Background

The U.S. Environmental Protection Agency (Agency or EPA) proposed regulations for 

the management of coal combustion residuals (CCRs) which was published in the Federal 

Register on June 21, 2010. This proposal, under the Resource Conservation and Recovery Act 

(RCRA), addressed the risks from disposal of CCRs generated from the combustion of coal at 

electric utilities and from independent power producers. Two regulatory options were proposed. 

Under the first option, EPA proposed to reverse its August 1993 Bevill Regulatory and May 

2000 Bevill Regulatory Determinations regarding CCR and to list CCRs as special wastes 

subject to hazardous waste regulations under subtitle C of RCRA when destined for disposal in 

landfill or surface impoundments. Under the second option, EPA proposed to leave the Bevill 

determination in place and regulate the disposal of CCR as non-hazardous solid waste under 

subtitle D of RCRA by issuing minimum national criteria. Both options would require 

composite liners, groundwater monitoring, structural stability requirements, corrective action, 

and closure/post closure care. 

EPA also solicited comments on all aspects of both proposed options. The Agency

received over 450,000 comments on the proposed rule. The majority of the comments focused

on which regulatory path the Agency should pursue for regulating CCRs, i.e., RCRA’s subtitle C

or subtitle D. EPA also conducted eight public hearings and took additional comments on the

proposed rule. EPA has established three dockets for this regulatory action under Docket ID No.

EPA-HQ-RCRA-2009-0640, Docket ID No. EPA-HQ-RCRA-2011-0392, and Docket ID No.

EPA-HQ-RCRA-2012-0028. All documents in these dockets are available at

http://www.regulations.gov. Although listed in the index, some information is not publicly

available, e.g., Confidential Business Information (CBI) or other information whose disclosure is

restricted by statute. Certain other material, such as copyrighted material, is not placed on the

Internet and will be publicly available only in hard copy form. Publicly available docket

materials are available either electronically in http://www.regulations.gov or in hard copy at the

OSWER Docket, EPA/DC, WJC West Building, Room 3334, 1301 Constitution Ave., NW,

Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday

through Friday, excluding legal holidays. The telephone number for the Public Reading Room is

(202) 566–1744, and the telephone number for the OSWER Docket is 202–566–0276.
2

After reviewing all the comments and additional data received, EPA is promulgating a 

final rule to regulate the disposal of CCR as solid waste under Subtitle D of RCRA. This rule 

addresses the risks from structural failures of CCR surface impoundments, groundwater 

contamination from the improper management of CCR in landfills and surface impoundments 

and fugitive dust emissions. 

The Agency has developed seventeen volumes summarizing comments on major topics 

covered in the proposed rule (see table below) and the Agency’s responses to those comments, as 

well as a separate volume summarizing comments provided during public hearings. Since EPA 

is finalizing a rule under subtitle D of RCRA, only those comments submitted on the proposed 

subtitle C rule that are also applicable to the final rule are addressed in the comment and 

response documents.

Volume Topic

1 General Comments 

2

RCRA Subtitle D Regulatory Approach (Legal issues/Self-implementing 

Design/Reliance on Certifications by an Independent Professional 

Engineer/Recordkeeping, State Submissions, Posting to the 

Internet/Finance Assurance/Alternative Approaches) 

3

Scope and Purpose/Effective Dates/Applicability/Off-site 

Disposal/Definitions 

4 Location Restrictions 

5 Design Criteria: Liners and Leachate Collection Systems

6 Design Criteria: Structural Integrity 

7

Operating Criteria: Endangered species/Surface water/Inspections/Run-on 

Run-off 

8 Operating Criteria: Air Criteria 

9 Groundwater and Corrective Action 

10 Closure and Post-Closure Care 

11 Additional Comments including Overfills/ Harmonization with ELG.

12 Beneficial Use 
3

Volume Topic

13 Risk Assessment 

14 State Authorities, Programs and Regulations 

15 Compendium of Damage Cases 

16 Regulatory Impact Analysis (RIA) 

17 EPA’s Assessment Program 

This volume summarizes comments received on the proposed design criteria for liners 

and leachate collection systems and provides EPA’s responses to those comments.

Comments and EPA Responses on the Design Criteria for Liners and Leachate Collection 

Systems

The design criteria proposed in the RCRA subtitle D proposal consisted of two primary 

requirements: (1) a composite liner system for new CCR landfills, existing and new CCR surface 

impoundments and all lateral expansions; and (2) structural stability requirements for existing 

and new CCR surface impoundments and all lateral expansions of these units. No design 

requirements were proposed for existing CCR landfills; rather, EPA proposed that these units 

could continue to receive CCRs and continue to operate as compliant landfills, without violating 

the open dumping prohibition. Conversely, EPA proposed that existing CCR surface 

impoundments, unlike existing CCR landfills, would be required to retrofit with a composite 

liner system within five years of the effective date of the rule or to close.

Proposed Liner Requirements

The proposed RCRA subtitle D design standards required that new CCR landfills, new 

CCR surface impoundments, and lateral expansions of CCR landfills and CCR surface 

impoundments be constructed with a composite liner and leachate collection and removal 

system. In the proposal, EPA defined a composite liner to mean a liner system consisting of two 

components; the upper component consisting of a minimum 30-mil flexible membrane liner 

(FML), and the lower component consisting of at least a two-foot layer of compacted soil with a 

hydraulic conductivity of no more than 1×10−7 cm/sec. FML components consisting of high 

density polyethylene (HDPE) were required to be at least 60-mil thick. The FML component 
4

must be installed in direct and uniform contact with the compacted soil component. Hydraulic 

conductivity means the rate at which water can move through a permeable medium (i.e., the 

coefficient of permeability).

In addition, EPA solicited comments on a number of issues, including: (1) whether any 

RCRA subtitle D option should allow facilities to use an alternative design for new CCR 

disposal units, so long as the owner or operator of the CCR disposal unit could obtain 

certification from an independent registered professional engineer or hydrologist that the 

alternative design would ensure that the appropriate concentration values for a set of constituents 

typical of CCRs will not be exceeded in the uppermost aquifer at the relevant point of 

compliance; i.e., 150 meters from the unit boundary down gradient from the unit, or the property 

boundary if the point of compliance (i.e., the monitoring well) is beyond the property boundary; 

(2) whether, in addition to the flexibility provided by section 3004(o)(2) of RCRA, the CCR 

regulations should also provide for alternative liner designs based on, for example, a specific 

performance standard, such as the performance standard in 40 CFR 258.40(a)(1), or a site 

specific risk assessment, or a standard that the alternative liner, such as a clay liner, was at least 

as effective as the composite liner; (3) whether clay liners designed to meet a 1x10-7cm/sec 

hydraulic conductivity might perform differently in practice than modeled in the risk assessment, 

including specific data on the hydraulic conductivity of clay liners associated with CCR disposal 

units; and (4) on the effectiveness of such additives as organosilanes, including any analyses that 

would reflect long-term performance of the additives, as well as the appropriateness of a 

performance standard that would allow the use of these additives in lieu of composite liners.

The Agency received a number of comments advocating the use of alternatives to the 

proposed composite liner. Most of these commenters recommended that geosynthetic clay liners 

be allowed as an alternative to the lower component stating that they have been proven to be an 

effective alternative to the two-foot layer of compacted soil. Some commenters stated that 

natural clay is not economically available in many parts of the country so, as an alternative, the 

CCR landfill owner or operator should have the ability to have a geosynthetic clay liner (GCL) 

approved as a replacement for the compacted soil component of the composite liner system if a 

demonstration is made that the alternative design meets the performance standard of the 

prescribed system. Other commenters stated that GCLs alone should be allowed as an 
5

alternative to the proposed composite liner. There were also comments opposing the use of 

alternative liners stating that alternatives have not been proven to be effective. 

EPA also received comments explaining that the proposed requirement for a leachate 

collection and removal system in new CCR surface impoundments was illogical since it would 

have to be constructed between the lower component (two feet of compacted soil) and upper 

component (flexible membrane liner) and the proposed rule specifically states that the flexible 

membrane liner component must be installed in direct and uniform contact with the compacted 

soil component. The inclusion of a leachate collection and removal system between the upper 

and lower components precludes direct and uniform contact. Placing a leachate collection and 

removal system between the lower and upper components of a composite liner would also 

compromise the integrity of the composite liner. These and other comments are discussed in 

more detail below.

1. Grandfathering of modern existing CCR surface impoundments and CCR landfills.

Comment: Obviously, the focus of the proposed rules are the older, unlined, existing 

CCR surface impoundments that were constructed 20 or more years ago absent of today’s 

environmental rules and construction standards. However, many existing CCR surface 

impoundments and existing CCR landfills have been permitted and constructed under current 

environmental rules that have required liners, leachate collection systems, and other modern 

controls. The liners and leachate collection systems in these modern facilities were approved by 

state regulatory agencies and were deemed protective of human health and the environment. 

However, in many cases the liner systems, leachate collection systems, or other controls, may not 

match the specific design criteria in the EPA’s proposed rule. There should be provisions in the 

EPA’s rules, allowing for the states, when adopting the EPA’s rules, to grandfather modern 

existing CCR surface impoundments and CCR landfills.

Comment Number: EPA-HQ-RCRA-2009-0640-06832-26

Organization: SCANA Corporation

Commenter Type: Electric Utility Company

Comment: Grandfathering of existing units encourages prolonging life of aging ponds 

and landfills. States routinely allow the continued operation of existing landfills and surface 

impoundments, without requiring the older units to comply with newly-imposed safeguards. In 
6

the 1999 Report to Congress, EPA estimated that the average age of surface impoundments and 

landfills was about 40 years. Yet many ponds and landfills are operating for decades longer

Comment Number: EPA-HQ-RCRA-2009-0640-06315-26

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Response: The Agency agrees with the commenter that “modern” existing CCR landfills 

and surface impoundments should not be subjected to the full suite of requirements in the 

proposed rule. However, EPA believes that certain existing CCR disposal units can pose risks 

so, in the final rule we are requiring these units to meet specific requirements to alleviate these 

risks. Specifically, the Agency is not subjecting existing CCR landfills to the location 

restrictions for placement above the uppermost aquifer, wetlands, fault areas, and seismic impact 

zones. Our rationale for this is that affected facilities would need to find additional disposal 

capacity, which would require utilities to procure new real estate for siting a new CCR landfill 

(which may be a significant distance from a power plant), obtain a new disposal permit for the 

CCR landfill (which can take an extended period of time), and transport significant volumes of 

CCRs great distances to newly-permitted facilities. EPA believes that applying these location 

restrictions to existing CCR landfills would cause a significant decrease in disposal capacity 

across the country. However, as proposed, EPA is requiring that existing CCR landfills must not 

be located in an unstable area unless the owner or operator demonstrates within 42 months of the 

effective date of the rule that recognized and generally accepted good engineering practices have 

been incorporated into the design of the CCR unit to ensure that the integrity of the structural 

components of the CCR unit will not be disrupted. Existing CCR landfills not meeting this 

requirement must close. Locating disposal units in unstable areas is generally recognized as 

having the potential to impact the structure of any disposal unit negatively and as such, increase 

the risks to human health or the environment through structural failures or leaching of 

contaminants into the groundwater. 

Additionally, existing landfills are not required to close or be retrofitted with a composite 

(or alternative composite) liner and a leachate collection and removal system. Given the volume 

of the material currently managed in CCR landfills, the potential for disruption in CCR disposal 

capacity if existing CCR landfills were required to retrofit would be significant. However, the 

final rule requires that only existing unlined CCR surface impoundment that are contaminating 
7

groundwater above a regulated constituent’s groundwater protection standard to stop receiving 

CCR and either retrofit or close, except in limited circumstances. EPA believes that existing 

unlined CCR surface impoundments should not be required to close prematurely if they are 

operating as designed and are complying with all the requirements of the rule, including all 

groundwater protection standards.

The final rule also requires the closure of any CCR landfill or CCR surface impoundment 

that cannot meet the applicable performance criteria for location restrictions or structural 

integrity established in this rule. Finally, those CCR surface impoundments that are no longer 

receiving CCR as of the effective date of the rule, but still contain water and CCR will be subject 

to all applicable regulatory requirements, unless the owner or operator of the facility dewaters 

and installs a final cover system on these inactive units no later than three years from the 

effective date of the rule.

2. Liner Design Requirements Applicable to Existing CCR Landfills.

a. The Need for Liners and Leachate Collection Systems.

Comment: These proposed rules are quite detailed and include provisions (such as 

requiring synthetic liners) that are not necessary in all instances.

Comment Number: EPA-HQ-RCRA-2009-0640-06011-11

Organization: Public Service Commission (PSC) - State of North Dakota

Commenter Type: State Government

Comment: EPA is proposing to modify the double liner and leachate collection and 

removal system requirement by substituting a requirement to install a composite liner and 

leachate collection and removal system. Tennessee agrees with this approach. This requirement 

and/or an equivalent requirement is identical to Tennessee’s standard for landfills and should be 

required in national standards regulating CCRs.

Comment Number: EPA-HQ-RCRA-2009-0640-06298-62

Organization: Tennessee Department of Environment and Conservation (TDEC)

Commenter Type: State Government

Comment: Ecology supports the proposed rule technical requirements that new lateral 

expansions and new landfills be constructed with a composite liner and leachate collection 

system. 
8

Comment Number: EPA-HQ-RCRA-2009-0640-06866-6

Organization: Washington State Department of Ecology

Commenter Type: State Government

Comment: In some regions of the country, the proposed composite liner system simply is 

not necessary to ensure protection of groundwater.

Comment Number: EPA-HQ-RCRA-2009-0640-06198-8

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06203-13

Organization: Arizona Public Service Company (APS)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06308-12

Organization: NRG Energy Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06863-41

Organization: Avista Corp.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06956-13

Organization: Tri-State Generation & Transmission

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08270-5

Organization: Cliffs Natural Resources Inc. (Cliffs)

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-09284-21

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09536-9

Organization: Tennessee Valley Authority

Commenter Type: Electric Utility Company
9

Comment Number: EPA-HQ-RCRA-2009-0640-09713-11

Organization: Indianapolis Power & Light Company (IPL)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09885-27

Organization: Progress Energy, Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: Wyoming believes that CCR landfills should be afforded the same opportunity 

to demonstrate that a liner is not needed as Subtitle D provides for municipal solid waste landfills 

in consideration of the fact that municipal waste poses a far greater threat to human health and 

the environment than CCR.

Comment Number: EPA-HQ-RCRA-2011-0392-0265-12

Organization: Department of Environmental Quality, State of Wyoming

Commenter Type: State Government

Comment: Before mandating ground water monitoring and liners with regulations, it 

should be proven that the CCR does contain materials detrimental to human health. The 

characteristics of the CCR site must be considered before mandating a liner. Numerous sites are 

likely to have constituents which will absorb, adsorb or chelete harmful constituents from a CCR 

leachate. If so, the site should require a liner or monitoring. Volume of leachates should be a 

consideration. If the volume is low then dispersion into surface or ground water of greater 

volume is likely to be of low consequence. If so, the site should not be required to have a liner 

or monitoring.

Comment Number: EPA-HQ-RCRA-2009-0640-06113-1

Organization: None Given

Commenter Type: Private Citizen

Comment: In certain situations, CCRs can be handled in a wet state, with no additional 

upgrades or impoundment liners. This would be true of applications where existing safeguards 

and handling practices provide sufficient environmental protection.
10

Comment Number: EPA-HQ-RCRA-2009-0640-06129-3

Organization: City Utilities of Springfield, MO

Commenter Type: Electric Utility Company

Comment: The continued use of compacted clay liners for Subtitle D standards should be 

allowed and is adequately protective of human health and the environment. Although a 

composite liner is required by the existing proposal, Arkansas and Louisiana regulations 

currently allow for a minimum of a two-foot layer of compacted clay with a hydraulic 

conductivity of no more than 1×10-7cm/sec and leachate collection to be utilized for CCR 

disposal units. Entergy supports the continued use of clay liner systems, in conjunction with 

groundwater monitoring programs to ensure no impacts are noted from the ash disposal units.

Comment Number: EPA-HQ-RCRA-2009-0640-06987-31

Organization: Entergy Services, Inc.

Commenter Type: Electric Utility Company

Comment: Clay liner systems should be an acceptable alternative to the composite liner 

system for existing facilities.

Comment Number: EPA-HQ-RCRA-2009-0640-10732_DEN-044-4

Organization: Platte River Power Authority

Commenter Type: Electric Utility Company

Comment: We suggest the following conditions for allowing a facility to continue 

operating without the requirement to install a composite liner: 

1. The facility has a natural clay liner that provides equivalent performance to the proposed 

composite liner. 

2. Usable groundwater resources do not exist below the facility. 

3. Groundwater monitoring demonstrates the facility is in compliance with appropriate 

standards. 

4. The containment features of the facility are stable against slope instability, are structurally 

sound, and are operated and maintained appropriately. 

5. In some states, e.g., Michigan, an industrial waste such as bottom ash can be shown to be he 

an “inert” and obtain an exemption from management as a waste. We propose that CCRs also 

have the ability to be shown to be inert on a case by case basis.
11

Comment Number: EPA-HQ-RCRA-2009-0640-08865-6

Organization: Geosyntec Consultants

Commenter Type: Other Company

Comment: CCR surface impoundments operating in accordance with the proposed 

composite liner requirements and applicable groundwater monitoring requirements do not need a 

leachate collection system, as any possible migration of constituents from the unit will be 

detected by the applicable groundwater monitoring system.

Comment Number: EPA-HQ-RCRA-2009-0640-06198-9

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment: Existing landfills that do not have a liner meeting the requirements specified 

in the rules or landfills that do not meet the requirements for landfill siting and design should be 

capped and hydraulic controls should be installed as needed to minimize movement of hazardous 

metals. Long-term monitoring should also be required.

Comment Number: EPA-HQ-RCRA-2009-0640-06313-89

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Comment: The proposed rules require composite liners for impoundments not only under 

Subtitle C but also for Subtitle D. While the Subtitle C option is rigid with respect to this 

requirement, the Subtitle D program should not be. The Louisiana solid waste regulatory 

program required engineered clay liners, having a coefficient of permeability no greater than l x 

l0-7cm/sec, up until rule modifications of 1993 after which new impoundments were required to 

have either composite liners or alternative liners that provide equivalent groundwater protection. 

The existing Cleco solid waste units were designed with the required clay liners while the newest 

one has a composite liner. Groundwater monitoring over the course of years has shown that 

there has been no adverse impacts to groundwater from Cleco impoundments. This suggests that 

under a Subtitle D program, use of engineered clay liners on existing solid waste units offers 

adequate protection without the extreme and unnecessary expense of excavating material from 

existing units and installing composite liners. The legislative history of the Bevill Amendment 

along with statements from the D.C. circuit court indicate that Congress directed EPA to install 

a regulatory program for CCR's that utilizes cost-effective controls and avoids imposition of 
12

undue regulatory costs on the electric utility industry if at all possible (EDF vs EPA, 852 F.2d 

1309, 1315 (D.C. Cir. 1988) Considering these directions and the proven performance of 

engineered clay liners, EPA should not require the installation of composite liners at existing 

units under a Subtitle D program.

Comment Number: EPA-HQ-RCRA-2009-0640-06868-7

Organization: Cleco Corporation

Commenter Type: Electric Utility Company

Comment: EPA should require the use of a composite liner system as the standard for 

containment and closure systems. This system has been demonstrated (by EPA) to be the most 

effective barrier methodology, regardless of the classification of the materials to be contained 

(hazardous or non-hazardous).

Comment Number: EPA-HQ-RCRA-2009-0640-06552-1

Organization: Agru America, Inc. (Agru)

Commenter Type: Other Company

Comment: EPA should consider this [the Pennsylvania] program as a model for effective 

state programs as it finalizes the Subtitle D regulations. The only substantial modification 

recommended to the Pennsylvania program model is that EPA should mandate a liner retrofit and 

leachate collection system requirement for existing surface impoundments as proposed in the 

Subtitle D approach.

Comment Number: EPA-HQ-RCRA-2009-0640-09281-18

Organization1:Exelon Power

Commenter Type: Electric Utility Company

Response: As discussed in the proposed rule, the CCR damage cases and EPA’s 

quantitative groundwater risk assessment clearly show the need for effective liners – namely 

composite liners – to very significantly reduce the probability of adverse effects. Therefore, the 

final rule requires new CCR landfills, new CCR surface impoundments, and all lateral 

expansions to be constructed with a composite liner. Similarly, to maintain the integrity of the 

geomembrane upper component of the composite liner it is essential to control the hydraulic 

head, i.e. the fluid level above the upper geomembrane component of the composite liner the 

integrity of the geomembrane. The primary function of a leachate collection and removal system
13

is to collect and convey leachate out of a unit and to control the depth of leachate above the liner 

Therefore, for new CCR landfills and lateral expansions, the final rule requires the installation of 

a leachate collections system to maintain the fluid level above the geomembrane at no more than 

12 inches (30 centimeters). As commenters rightly pointed out, requiring a leachate collection 

system as proposed for new CCR surface impoundments is counterintuitive and would 

compromise the integrity of the composite liner. Accordingly, the final rule does not require 

leachate collection systems for new CCR surface impoundments and lateral expansions.

Comment: The final regulations should address specific requirements for design of the 

leachate collection system, and should specify requirements for adequate quality assurance/ 

quality control for construction of the liner and leachate collection system.

Comment Number: EPA-HQ-RCRA-2009-0640-06866-6

Organization: Washington State Department of Ecology

Commenter Type: State Government

Response: The final rule requires a leachate collection system designed, constructed and 

operated to maintain less than a 12 inch (30-centimeter) depth of leachate over the composite 

liner or alternative composite liner. This is the same requirement for leachate collection systems 

established in the regulations for municipal solid waste landfills at 40 CFR §258. The Agency 

has chosen not to specify specific requirements for the design and construction of the leachate 

collection system to provide flexibility for its design and construction based on site specific 

conditions. Additionally, the final rule requires that the design and construction be certified by a 

qualified professional engineer. Moreover, EPA has developed recommended guidance for the 

design of leachate collection systems and construction quality assurance and quality control of 

liners and leachate collection systems. The recommended guidance is available at 

http://www.epa.gov/epawaste/nonhaz/industrial/guide/pdf/chap7b.pdf.

b. Existing CCR Landfills Should be Required to Retrofit to a Composite Liner System.

EPA did not propose to require existing CCR landfills to retrofit with a liner because

these units presented significantly lower risks than those associated with CCR surface

impoundments. The Agency was also concerned that potential disposal capacity shortfalls could

result if existing CCR landfills were required to close, given the volume of the material involved,

and was concerned about the potential for significant disruption in energy supplies and

distribution if all disposal units needed to be simultaneously closed. The Agency concluded that
14

greater public health concerns existed based on the potential for open dumping of CCRs if all

disposal units were forced to close than by the potential risks caused by the continued use of

these existing unlined landfills, given that the landfills would also be subject to the other rule

requirements, including groundwater monitoring and corrective action. The Agency received no

information during the comment period to contradict those initial conclusions. The risks

associated with unlined (or clay lined) CCR landfills remain significantly lower than those

associated with CCR surface impoundments. Unlined units were found to present the greatest

risks. Unlined impoundments result in cancer risks above 1×10-5for trivalent (3×10-4) and

pentavalent (4×10-5) arsenic, as well as noncancer risks above an HQ of 1 for trivalent arsenic

(8), molybdenum (4) and thallium (2). Unlined landfills result in cancer risks above 1×10-5for

trivalent arsenic (2×10-5), and within the OSWER risk range for pentavalent arsenic (1×10-6).

Clay-lined units were found to present risks lower than unlined units, but still within the OSWER

risk range. Clay-lined impoundments result in cancer risks for trivalent arsenic (7×10-6). Claylined landfills also result in cancer risks for trivalent arsenic (1×10-5

). Consequently, the final

rule allows existing CCR landfills without composite liners to continue to operate without

retrofitting. EPA did not receive specific comments stating that existing CCR landfills should be

retrofitted with composite liners. 

3. Liner Design Requirements Applicable to New CCR Landfills and Lateral Expansions.

a. No Technical Requirements Proposed for Leachate Collection Systems. 

Comment: The final regulations should address specific requirements for design of the 

leachate collection system, and should specify requirements for adequate quality 

assurance/quality control for construction of the liner and leachate collection system.

Comment Number: EPA-HQ-RCRA-2009-0640-06866-6

Organization: Washington State Department of Ecology

Commenter Type: State Government

Response: EPA is finalizing a rule that requires new CCR landfills and lateral expansions

to be constructed with a leachate collection and removal system that meets a specific

performance standard: that the system is designed and constructed to maintain less than a 30-cm

depth of leachate over the liner. The design of the composite liner and leachate collection and

removal system must be prepared by, or under the direction of, and certified by a qualified

professional engineer. This requirement provides flexibility for professional engineers to design
15

the leachate collection and removal system that are appropriate for site-specific conditions and

that meet the minimum leachate depth requirement. This approach has been effective in

protecting public health and the environment for MSWLFs. The commenter provided no

information to suggest that it will not be effective for CCR landfills, and the Agency is aware of

none. 

4. Liner Design Requirements Applicable to Existing CCR Surface Impoundments.

a. Retrofit or Closure of Unlined CCR Surface Impoundments Regardless of Performance. 

Comment: We have constructed two CCR surface impoundments using high density 

polyethylene (“HDPE”) synthetic liners where the sub-base component of the composite liner 

does not meet the proposed requirement for two feet of clay with permeability less than or equal 

to 1.0 x 10-7cm/sec. These surface impoundments are safe and functioning as designed. 

However, under the proposed rule, they, along with other “lined” CCR surface impoundments 

that do not meet EPA’s definition of “composite liner” would be required to be closed before 

they reach their maximum storage capacity. EPA must include the D Prime component when it 

promulgates a RCRA subtitle D non-hazardous CCR regulation, such that it does not mandate 

the closure of CCR surface impoundments simply because they do not meet EPA’s proposed 

liner design standards regardless of how the facility is performing. 

Comment Number: EPA-HQ-RCRA-2009-0640-06398-29

Organization: Duke Energy

Commenter Type: Electric Utility Company

Response: As discussed in section VIII. B. 7, EPA has concluded that it is not 

necessary to require existing CCR surface impoundments to retrofit with a composite liner or 

close until the existing CCR surface impoundment presents an immediate threat to groundwater. 

Therefore, EPA is allowing CCR surface impoundments that are lined with a composite liner, or 

a clay liner that meets the technical requirements in the rule to continue to operate and receive 

CCRs, provided the owner or operator of the unit certifies that the §257.71, Table I contaminants 

are not migrating from the existing unlined CCR surface impoundment into groundwater at a 

statistically significant increase over background as determined through a groundwater 

monitoring program in accordance with §§257.90 – 257.94. However, if the existing unlined 

CCR surface impoundments are found to be leaking, they are subject to the corrective action 

requirements of today’s rule and must also either retrofit with a composite liner or alternative 
16

composite liner, or close in accordance with the closure requirements at §257.100, except in 

limited circumstances. The Agency has concluded that this revised approach will still ensure the 

protection of groundwater resources. 

b. Technical Requirements Applicable to Existing CCR Surface Impoundments Depending on 

Closure Dates.

Comment: CCR surface impoundments receiving CCR for treatment or disposal should 

be regulated from initial design through completion of post-closure monitoring requirements. 

For existing CCR surface impoundments, there should be two categories; (1) CCR surface 

impoundments to be closed within five years from the effective date of the CCR final rule, and 

(2) CCR surface impoundments that will be used more than five years after the effective date of 

the CCR final rule.

(1) Regulations for existing CCR surface impoundments to be closed within five years of the 

effective date of the CCR final rule should include structural analysis with repair/improvements 

required to meet a dam safety factor of 1.2. Additional requirements should include quarterly 

inspections, installation of groundwater monitoring wells, semiannual groundwater monitoring, 

closure plan, post-closure monitoring and maintenance and financial assurance in an amount 

sufficient to cap the surface impoundment and to perform environmental investigation and 

cleanup should the CCR surface impoundment fail or have releases to groundwater and surface 

water. The CCR surface impoundment owner or operator should be required to submit a 

statement committing to closure of the CCR surface impoundment within five years and 

acknowledge the responsibility to comply with (2) below should the CCR surface impoundment 

not be closed on schedule.

(2) Regulations for existing CCR surface impoundments to be operated for more than five years 

after the effective date of the CCR final rule should include a structural analysis with 

repair/improvements required to meet a dam safety factor of 1.5. In addition, these surface 

impoundments should be retrofitted with a synthetic liner to prevent the migration of CCR 

contaminants into ground water and the owner or operator of the CCR surface impoundment 

should be required to obtain a solid waste processing/disposal permit following the RCRA 

subtitle D public participation process. Additional requirements should include quarterly 

inspections, installation of groundwater monitoring wells, semi-annual groundwater sampling, 

annual estimation of remaining life, closure plan with cover, post-closure monitoring and 
17

maintenance plan and financial assurance sufficient to perform environmental investigation and 

clean up should the CCR surface impoundment fail or release contaminants to groundwater or 

surface water.

Comment Number: EPA-HQ-RCRA-2009-0640-06298-30

Organization: Tennessee Department of Environment and Conservation (TDEC)

Commenter Type: State Government

Response: We disagree with the commenter that CCR surface impoundments that will not 

be operating and receiving CCRs for more than five years should be subject to fewer 

requirements than those CCR surface impoundments that will be operating and receiving CCRs 

from more than 5 years. First, we would note that the Agency does not have the authority to 

require the owner or operator of the CCR surface impoundment to obtain a solid waste 

processing/disposal permit following the RCRA subtitle D public participation process nor 

impose financial assurance requirements. Thus, the Agency could not require such provisions, 

even if it wanted to. More importantly, the risks to human health and the environment can be the 

same whether the CCR surface impoundment is operating and receiving CCRs for less than or 

more than five years. Therefore, the Agency has not made this change. However, with that said, 

the Agency has made a number of modifications to the proposed rule, which we have determined 

provide greater flexibility for the owner or operator of the CCR surface impoundment, and at the 

same time are protective. Specifically, 

 owners or operators of existing CCR surface impoundments that impound CCR, CCR 

slurry, or liquids to an elevation of five feet or more above the downstream toe of the 

structure and have a storage volume of 20 acre-feet or more; or impound CCR, CCR 

slurry, or liquids to an elevation of 20 feet or more above the downstream toe of the 

structure must demonstrate that the existing CCR surface impoundment meets and will 

maintain a static structural stability factor of safety of greater than or equal to 1.50 under 

long-term loading conditions. This requirement has been modified from the proposed 

rule. EPA proposed this size threshold based on Mine Safety and Health Administration 

(MSHA) coal slurry pond requirements. However, EPA modified MSHA’s language 

from 5 feet above the “upstream toe” to 5 feet above the “downstream toe” in order not to 

capture incised CCR surface impoundments. Incised CCR surface impoundments do not 

have embanked portions, and therefore do not present a threat of structural failure. 
18

 all existing CCR surface impoundments are subject to the groundwater monitoring and 

corrective action requirements in §§257.90 through 257.98, and must conduct weekly 

inspections and annual inspections that must be certified by a qualified professional 

engineer. 

 owners or operators of existing CCR surface impoundment are required to prepare a 

written closure plan that explains the method of closure, a description of the final cap, 

and an estimate of the year in which closure will be completed. 

 all existing CCR surface impoundments are also subject to the post-closure care 

requirements of §257.103 of today’s final rule. 

5. Liner Design Requirements Applicable to New CCR Surface Impoundments and Lateral 

Expansions of Existing and New CCR Surface Impoundments.

a. Definition of Composite Liner is Incorrect.

Comment: Section 257.71 and 257.72 describes the liner as 'composite' with a leachate 

collection system between the two liner components. This is a 'double liner system' not a 

composite liner system. Given the direct and uniform contact provision, the rule description of 

composite system needs to be corrected.

Comment Number: EPA-HQ-RCRA-2009-0640-03444-35 & 36

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-08226-45

Organization: Ohio Environmental Protection Agency

Commenter Type: State Government

Comment: For new surface impoundments and lateral expansions, revise the 

requirement for the installation of a leachate collection system between the lower and upper 

component to installation of a leachate collection system above the upper component.

Comment Number: EPA-HQ-RCRA-2009-0640-03444-35 & 36

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09282-13

Organization: North Carolina Department of Environment and Natural Resources

Commenter Type: State Government
19

Comment Number: EPA-HQ-RCRA-2009-0640-09284-23

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment: The proposed version states "With a composite liner, as defined in paragraph 

(a)(2) of this section and leachate collection system between the upper and lower components of 

the composite liner." We believe this should read "With a composite liner, as defined in 

paragraph (a)(2) of this section and leachate collection system placed above/on top of the 

composite liner." The composite liner must be in installed in direct and uniform contact and the 

leachate collection system should be placed on top of and not in the middle of the two 2 parts of 

the liner.

Comment Number: EPA-HQ-RCRA-2009-0640-06819-24

Organization: Missouri Department of Natural Resources

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09284-22

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Response: EPA acknowledges that the proposed requirement for a leachate collection 

system between the upper and lower components of the composite liner for new surface 

impoundments and lateral expansions was proposed in error. For the reasons stated in the 

response to similar comments in section c (Composite Liner Integrity) below, the final rule is not 

requiring a leachate collection system for new CCR surface impoundments and lateral 

expansions.

b. Composite Liner Placement. 

Comment: Composite liners should not be mandated throughout a wet/surface 

impoundment disposal area. Composite liners are an appropriate requirement beneath the CCR 

surface impoundment proper or over the CCR surface impoundment basin where a persistent 

source of water exists, but not beneath the containment dikes or other impounding embankments 

where a composite liner represents a weak plane in the foundation of the containment structure 

and poses stability issues. Rather, with regard to containment dike/impounding embankment 

areas, the use of soil and/or other non-geosynthetic seepage barriers in combination with 

subsurface drains is a better approach for stability, management of seepage and leachate, and 
20

long-term surface and groundwater protection. Mechanisms to promote the passive dewatering 

of the CCRs, and collect and control seepage and leachate, will yield the greatest dividends for 

stability and long-term environmental protection. The perfect liner system and watertight 

bathtub do not exist.

Comment Number: EPA-HQ-RCRA-2009-0640-03451-5

Organization:

Commenter Type: Private Citizen

Response: The Agency agrees that a composite liner beneath a CCR surface 

impoundment containment dike or berm is not appropriate since the liner could create an 

unstable foundation and lead to leakage or the structural failure of the dike or berm. EPA did not 

intend to require a composite liner beneath the CCR surface impoundment containment dikes or 

other impounding embankments, but was not clear in the proposed rule. Therefore, the Agency 

is specifying in the final rule design requirements that composite liners are to be installed to 

encompass the CCR surface impoundment containment dikes or other impounding 

embankments. 

c. Composite Liner Integrity

Comment: A liner integrity survey should be conducted on the flexible membrane liner 

(FML) component at an impoundment. This concept could be inserted where the direct and 

uniform contact provision is brought up. It could be phrased in terms of the FML component 

being without tears or holes (and maybe even wrinkles when used in landfills) after deployment. 

It wouldn't hurt to include landfills too, but is critical for the impoundment due to the separation 

of the FML from the compacted soil liner.

Comment Number: EPA-HQ-RCRA-2009-0640-08226-45

Organization: Ohio Environmental Protection Agency

Commenter Type: State Government

Response: As stated previously and discussed in detail below, the final rule does not 

require a leachate collection system between the upper and lower components of the composite 

liner for CCR surface impoundments. Therefore, there will not be a separation between the 

geomembrane (FML) component and the compacted soil component of the composite liner. 

Nevertheless, upon completion of construction of the CCR landfill, CCR surface impoundment,

or any lateral expansion, the owner or operator must obtain a certification from a qualified 
21

professional engineer that the composite liner (or, if applicable, alternative composite liner) and 

the leachate collection and removal system has been constructed in accordance with the 

requirements of the final rule. This certification should assure that the geomembrane component 

is installed in direct and uniform contact with the compacted soil component.

Comment: Earthern embankments often develop cracking. When the embankment 

cracks, the 2-ft thick layer of compacted soil would likely also have cracked. At that point, a 

single 30-mil HDPE liner becomes the sole line of defense. Suggest considering 2 liners placed 

on 2-ft compacted soil and the leachate collection system. Also, “direct and uniform contact 

with the compacted soil component” is unrealistic as HDPE installation typically have wrinkles.

Comment Number: EPA-HQ-RCRA-2009-0640-09337-53

Organization: Arizona Department of Environmental Quality (ADEQ)

Commenter Type: State Government

Response: The Agency has no experience or data that show that a composite liner 

consisting of two feet of compacted soil with a hydraulic conductivity of 1 x 10-7cm/sec and a 

single 30-mil geomembrane in direct and uniform contact with the compacted soil is not an 

effective liner system. EPA’s risk assessment shows that composite liners were the only liner 

type modeled that effectively reduced risks from all pathways and constituents far below human 

health and ecological criteria for every sensitivity analysis conducted.

Comment: The proposal requires that existing and new CCR surface impoundments and 

all lateral expansions of CCR surface impoundments to be constructed with a composite liner 

system having a leachate collection system between the upper component (flexible membrane 

liner) and lower component (compacted soil barrier). However, the regulatory text also requires 

the two components of the composite liner to be installed in direct and uniform contact with each 

other. It is not possible to meet both requirements, as the inclusion of a leachate collection 

system between the upper and lower components precludes intimate contact and makes the 

proposed design very inefficient, resulting in a significant leakage rate through the FML because 

it will not be supported by a clay liner. Leaving the rule in its present form will create confusion 

and difficulty, which would leave owners vulnerable to lawsuits since there will be no state 

agency to interpret the rules.
22

It has been well established that "intimate contact" between the two liner components is a 

major factor in the effectiveness of composite liner systems. Placing any material between the 

liner components defeats the purpose of requiring a composite liner system in the first place, 

particularly if the liquids passing the FML are not intended to be collected and removed. Also, 

“direct and uniform contact with the compacted soil component” is unrealistic as HDPE 

installations typically have wrinkles.

EPA needs to decide which is more important—that is, having a leak detection/collection 

system or an effective liner system. EPA should consider requiring a double liner system, with 

the leak detection/leachate collection system between two FMLs, leaving the lower FML in true 

intimate contact with the underlying compacted soil barrier. In addition, earthen embankments 

often develop cracking. When the embankment cracks, the 2-ft thick layer of compacted soil 

would likely also have cracked. At that point, a single 30-mil HDPE liner becomes the sole line 

of defense, which further suggests the consideration of two liners placed on 2-ft of compacted 

soil and a leachate collection system. 

Because this requirement applies to surface impoundments (i.e. standing water bodies) 

the leachate collection system cannot logically be intended to control the depth of leachate; it 

must be intended to detect, contain, and collect contain leakage through the FML. Yet nothing in 

the proposed rule specifies that the system must drain to collection points. If a leachate 

collection/leak detection system is to remain a requirement, please include a requirement that the 

system be designed to gravity drain to collection points.

Comment Number: EPA-HQ-RCRA-2009-0640-06517-4 & 12

Organization: None Given

Commenter Type: Anonymous

Comment: As currently proposed, placing a flex geomembrane liner (FML) directly 

over a leak detection system makes the proposed design very inefficient, resulting in a significant 

leakage rate through FML because it will not be supported by a clay liner. A composite liner 

(combination of compacted clay and FML) beneath a surface impoundment would provide 

adequate protection of ground water. As a verification of the soundness of the impoundment a 

perimeter ground water monitoring system could also be required.
23

Comment Number: EPA-HQ-RCRA-2009-0640-06018-7

Organization: Indiana Department of Environmental Management (IDEM)

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-06298-74

Organization: Tennessee Department of Environment and Conservation (TDEC)

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-06398-41

Organization: Duke Energy

Commenter Type: Electric Utility Company

Comment: The introduction of the leachate collection system between the two 

components of the composite liner would defeat the composite action. 

Comment Number: EPA-HQ-RCRA-2009-0640-03444-35 & 36

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-06424-12

Organization: Garrett & Moore, Inc.

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-06819-24

Organization: Missouri Department of Natural Resources

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09284-23

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09349-10

Organization: Santee Cooper

Commenter Type: Electric Utility Company

Comment: Proposed 40 CFR §257.71(a)(I) and 40 CFR §257.72(a)(2) specify that a 

composite liner be installed on existing and new CCR surface impoundments respectively. 

Included in these requirements is the stipulation that a leachate collection system be installed 

between the upper and lower components of the composite liner. This makes no sense since 

proposed 40 CFR §257.70(a)(2) and 40 CFR §257.72(a)(2) require that the composite liner be a 
24

two part system composed of a flexible membrane liner and a compact soil layer in direct contact 

with each other.

Comment Number: EPA-HQ-RCRA-2009-0640-06352-18

Organization: Dayton Power & Light Company (DP&L)

Commenter Type: Electric Utility Company

Comment: Given that both components of the liner system must be in direct contact with 

one another, there is no way that a leachate collection system can be installed between these two 

components. EPA should eliminate the proposed requirement from the final regulations 

directing that leachate collection systems in the case of surface impoundments be between the 

upper and lower components of the liner system when these components must be “in direct and 

uniform contact” with one another. 

Comment Number: EPA-HQ-RCRA-2009-0640-06198-9

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06352-18

Organization: Dayton Power & Light Company (DP&L)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06529-41

Organization: NiSource Corporate Services

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06532-35

Organization: Southern Illinois Power Cooperative

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06827-14

Organization: Oklahoma Gas and Electric Company (OG&E)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06863-42

Organization: Avista Corp.

Commenter Type: Electric Utility Company
25

Comment Number: EPA-HQ-RCRA-2009-0640-09885-28

Organization: Progress Energy, Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-54

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: The design criteria incorrectly require a leachate collection system between 

the upper and lower components of the composite liner system. Delete “and a leachate collection 

system between the upper and lower components of the composite liner” in the first sentence. 

Delete “and leachate collections system” in the second sentence.

Comment Number: EPA-HQ-RCRA-2009-0640-06832-28

Organization: SCANA Corporation

Commenter Type: Electric Utility Company

Comment: We believe EPA made an error in proposing a leachate collection system for 

impoundments where the leachate collection system is placed between the upper and lower 

components of the composite liner. In landfills a leachate collection system is placed above the 

liner and the proposal details the upper flexible membrane liner must be in direct contact with the 

lower clay liner.

Comment Number: EPA-HQ-RCRA-2009-0640-07047-30

Organization: Great River Energy

Commenter Type: Electric Utility Company

Comment: The proposed rule requires a composite liner system for existing 

impoundments which are to be retrofitted and kept in operation. The rule specifies that a 

leachate collection system is to be placed between the flexible membrane liner and the 

compacted soil barrier. However, paragraph 257.71(a)(2) requires direct and uniform contact

between the two liner components. This is not possible with a leachate collection system 

between them. This would create a situation where owners would be out of compliance with one 

requirement or the other and vulnerable to lawsuits. Please revise these paragraphs to remove 

the requirement for intimate contact between the two liner components.
26

Comment Number: EPA-HQ-RCRA-2009-0640-07534-4 & 6

Organization: Aquaterra Environmental Solutions, Inc.

Commenter Type: Other Company

Response: The Agency agrees that the leachate collection and removal system 

requirements proposed for CCR surface impoundments would be counterproductive and 

proposed this requirement in error. The integrity of the composite liner system is dependent 

upon the direct and uniform contact of the upper FML component with the lower soil 

component. The proposed requirement to construct a leachate collection system between the 

FML and soil components would prevent the direct and uniform contact of the upper and lower 

components and, therefore, compromise the integrity of the composite liner. For this reason, 

EPA has revised the requirements for CCR surface impoundments accordingly and is not 

requiring a leachate collection and removal system for new or existing surface impoundments. 

As the commenter argued, a leachate collection and removal system in a surface impoundment is 

not intended to control the depth of leachate, but it is intended to detect, contain, and collect 

leakage through the upper component of the composite liner system. Therefore, a leachate 

collection and removal system in a surface impoundment designed for its intended purpose 

would require installation of the leachate collection and removal system between a double liner 

system. EPA’s risk analyses show that a single composite liner system will protect human health 

and the environment at most sites across the country, and thus, a double liner system is not 

necessary as a national standard. Finally, since the Agency is not requiring a double liner 

system, with the leachate collection and removal system between the liners, the Agency is not 

requiring the owner or operator to monitor the system for leakage. 

Comment: Nothing in the proposed rule indicates that owners or operators are required to 

inspect the [leachate collection] system to monitor leakage, or to take any action in the event of a 

leak and that the Agency should consider revising the rules to add monitoring requirements and 

specify actions required upon detection of a leak.

Comment Number: EPA-HQ-RCRA-2009-0640-06517-4 & 12

Organization: None Given

Commenter Type: Anonymous
27

Response: As discussed previously, the final rule is not requiring the installation of a 

leachate collection system for CCR surface impoundments. Nevertheless, CCR surface 

impoundments and lateral expansions must be examined by a qualified person as follows

at intervals not exceeding 7 days for any appearances of actual or potential structural weakness 

and other conditions which are disrupting or have the potential to disrupt the operation or safety 

of the CCR unit and must be inspected annually by a qualified professional engineer to ensure 

that the design, construction, operation, and maintenance of the CCR unit is consistent with 

recognized and generally accepted good engineering standards. Although it was not a 

requirement in the proposed rule, the final rule requires the same inspections for CCR landfills 

and lateral expansions as is required for CCR surface impoundments.

Comment: Composite liners should not be mandated throughout a wet/surface 

impoundment disposal area. Composite liners are an appropriate requirement beneath the 

impoundment proper or over the impoundment basin where a persistent source of water exists, 

but not beneath the containment dikes or other impounding embankments where a composite 

liner represents a weak plane in the foundation of the containment structure and poses stability 

issues. Rather, with regard to containment dike/impounding embankment areas, the use of soil 

and/or other non-geosynthetic seepage barriers in combination with subsurface drains is a better 

approach for stability, management of seepage and leachate, and long-term surface and 

groundwater protection. Mechanisms to promote the passive dewatering of the CCRs, and 

collect and control seepage and leachate, will yield the greatest dividends for stability and longterm environmental protection. The perfect liner system and watertight bathtub do not exist.

Comment Number: EPA-HQ-RCRA-2009-0640-03451-5

Organization:

Commenter Type: Private Citizen

6. Liner Design Requirements Applicable to New CCR Landfills, Existing and New CCR 

Surface Impoundments and All Lateral Expansions.

a. Use of Composite Liners Only. 

Comment: The Agency should not allow alternative liner designs for the CCR landfills 

and CCR surface impoundments. The science of liner design for CCR waste containment 

structures has not advanced to the point where alternative liner designs should be allowed. A 
28

standard composite liner should be the required standard. Using an alternate design that consists 

of a liner of only one type of material, such as clay soils or a high density polyethylene (HDPE) 

flexible membrane liner (FML) would not be appropriate since each of these materials has 

limitations to its use. Rather, a composite liner composed of both types of materials would 

mitigate the shortcomings of each separate material. Other liners, such as geosynthetic clay 

liners, which rely on the hydration of sodium bentonite, have not been tested with CCR leachate. 

Furthermore, laboratory tests will not determine their long-term viability in the field. 

It is impossible to predict with any certainty what the CCR materials will do in these 

landfills over time. The science of CCR materials is still expanding at a rapid rate, and our 

understanding of leachates formed from the different sources of coal and the different 

combustion processes over time is not fully defined. Even for facilities that use the same source 

of coal with the same combustion processes, the temperature gradients, moisture holding 

capacity of the CCR wastes, and changes in oxidation/reduction potentials within a CCR landfill 

can change the dominant mineral phases and more importantly, the solubility of the metals in the 

wastes. Therefore, leachate compositions are variable in both species present and 

concentrations. Because of this variability, the interactions between metal-laden leachates from 

CCR’s and different liner materials have not been studied.

A composite liner with an effective leachate collection and removal system should be the 

standard. Hydraulic control of both the FML component and the compacted clay layer (CCL) 

component of a composite liner, is reasonably well understood and can be designed to minimize 

the flow of aqueous liquids. With alternative designs, there is no assurance and no validation 

that the alternative design can achieve the same level of performance. In the absence of test data 

on proposed alternative designs, allowing alternative designs on new CCR disposal units would 

be irresponsible. 

Comment Number: EPA-HQ-RCRA-2009-0640-06313-103

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Response: EPA agrees that new CCR disposal units should only install composite liner 

systems but disagrees that all alternative designs for a composite liner system should be rejected 

as insufficiently protective. As discussed in subsequent comment responses, many commenters 
29

provided strong evidence that the composite liner system required in the proposed rule is not 

always feasible or necessary to protect groundwater resources, and the Agency agrees. 

Researchers have demonstrated the protectiveness of alternative liners, particularly 

geomembranes (GM) over geosynthetic clay liners (GCL).1 For example, the available data on 

the hydraulic effectiveness of GM/GCL composite liners demonstrates that a GM/GCL meets or 

exceeds the hydraulic performance of a GM/CCL liner design. Some states may also have 

requirements for alternative liner designs that are more stringent than the composite liner 

requirement, and the approach in the proposed rule would have effectively overruled those 

requirements by mandating that the facility install only a composite liner. Although EPA does 

not have data on the compatibility of alternative liners with CCR and CCR leachate, the final 

rule requires that the owner or operator provide certification by a qualified professional engineer 

that the alternative composite liner, at a minimum, meets or exceeds the performance of a 

composite liner with respect to differential settlement, slope stability, puncture resistance, 

compatibility with CCR (chemical resistance), and compatibility with sub-grade conditions.

EPA also received comments from some states; e.g., Alaska, stating that sufficient soil 

does not always exist in the state that would provide the required hydraulic conductivity. 

Allowing alternatives to the two feet of compacted soil will provide facilities in these states with 

a liner material with an equivalent or better hydraulic performance than two feet of compacted 

native soil. EPA has also evaluated the performance of compacted clay liners, geomembranes

(FMLs and HDPEs), geosynthetic clay liners, and composite liners with two feet of compacted 

soil and determined that GM/GCL composite liners can be constructed to achieve hydraulic 

efficiencies in the range of 99 to 99.9%. These high efficiencies demonstrate that the GCL 

component of a GM/GCL composite liner is effective in impeding leakage through holes in the 

GM component of the liner.2 EPA also developed guidance for the selection and installation of 

various types of liners including GCLs.

3 Therefore, upon consideration of all the comments, 

EPA research, technical papers, and a thorough review of EPA’s revised risk assessment, EPA 

 

1 USEPA, “Assessment and Recommendations for Improving the Performance of Waste Containment 

Systems,” EPA 600/R-02/029, December 2002.

2 USEPA, “Assessment and Recommendations for Improving the Performance of Waste Containment 

Systems,” EPA 600/R-02/029, December 2002.

3 USEPA, “Guide for Industrial Waste Management,” Chapter 7 

(http://www.epa.gov/osw/nonhaz/industrial/guide/pdf/chap7b.pdf).
30

acknowledges that the rule, as proposed, was overly prescriptive and should allow for alternative 

liners that are at least as protective of groundwater as a composite liner. 

b. Use of Alternative Liner Designs. 

Comment: It is not appropriate to allow alternative designs for new disposal units. It is 

impossible to predict with any certainty what the CCR materials will do in these landfills over 

time. The science of CCR materials is still expanding at a rapid rate, and our understanding of 

leachates formed from the different sources of coal and the different combustion processes over 

time is not fully defined. Even for facilities that use the same source of coal with the same 

combustion processes, the temperature gradients, moisture holding capacity of the CCR wastes, 

and changes in oxidation/reduction potentials within a CCR landfill can change the dominant 

mineral phases and more importantly, the solubility of the metals in the wastes. Therefore, 

leachate compositions are variable in both species present and concentrations. Because of this 

variability, the interactions between metal-laden leachates from CCR’s and different liner 

materials have not been studied.

The science of liner design for CCR waste containment structures has not advanced to the 

point where alternative liner designs are acceptable. A standard composite liner should be the 

required standard. Using an alternate design that consists of a liner of only one type of material, 

such as clay soils or a high density polyethylene (HDPE) flexible membrane liner (FML) would 

not be acceptable since each of these materials has limitations to its use, but a composite liner 

composed of both types of materials would mitigate the shortcomings of each separate material. 

Other liners, such as geosynthetic clay liners, which rely on the hydration of sodium bentonite, 

have not been tested with CCR leachate. Furthermore, laboratory tests will not determine their 

long-term viability in the field.

Comment Number: EPA-HQ-RCRA-2009-0640-06313-103

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Response: For the reasons stated in the response to the previous comment, EPA agrees 

that new CCR disposal units should only install composite liner systems. However, the Agency 

believes composite liners consisting of an alternative to the two feet of compacted soil with a 

hydraulic conductivity of 1 x 10-7cm/sec as the lower component and a geomembrane upper 
31

component can be effective liners provided that the liquid flow rate through the lower component 

of the alternative composite liner is no greater than the liquid flow rate through two feet of 

compacted soil. The final rule is allowing such alternative composite liners provided the liquid 

flow rate equivalency is certified by a qualified professional engineer.

Comment: In a performance-based regulatory system, there are a number of technologies 

and techniques that will reduce the risk of offsite migration of contaminants at least as much as 

composite liners, including: Subsurface slurry wall technology, In-situ chemical fixation (ISCF), 

In-situ solidification/stabilization (ISS), Natural attenuation, supported by groundwater modeling 

and monitoring and enhanced natural attenuation by chemical additions, and In situ secondary 

mineral growth/precipitation and contaminant sequestration in ash deposits (including enhanced 

processes by chemical additions).

Comment Number: EPA-HQ-RCRA-2009-0640-06300-30

Organization: Southern Company on behalf of itself and its four subsidiaries: Alabama Power 

Company, Georgia Power Company, Gulf Power Company, and Mississippi Power Company

Commenter Type: Electric Utility Company

Response: The Agency does not have sufficient experience or data on the systems 

suggested by the commenter to warrant allowing their use as an alternative to composite liners. 

Consequently, the final rule is requiring composite liners, or alternative composite liners as 

described in the response to the previous comment, for new CCR disposal units and all lateral 

expansions.

Comment: States should have the flexibility to review and approve alternative liner 

designs that will provide adequate protection.

Comment Number: EPA-HQ-RCRA-2009-0640-03444-34

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09284-21

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09337-35 & 36

Organization: Arizona Department of Environmental Quality (ADEQ)

Commenter Type: State Government
32

Response: EPA is allowing alternative composite liners as described above to provide a 

level of flexibility for site-specific conditions. The alternative composite liner must be certified 

by a qualified professional engineer. States are also free to develop their own regulations and/or 

permitting programs using their solid waste laws or other state authorities that would require 

public notice, hearings, and State approval of alternative liner designs.

Comment: The Subtitle D rule should allow for alternate liner systems. 

Comment Number: EPA-HQ-RCRA-2009-0640-06252-17

Organization: Minnkota Power Cooperative, Inc. (Minnkota)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06254-19

Organization: Sunflower Electric Power Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06722-21

Organization: Arkansas Electric Cooperative Corporation (AECC)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08220-19

Organization: PowerSouth Energy Cooperative

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08253-27

Organization: Xcel Energy

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08841-32

Organization: Deseret Generation and Transmission Co-operative

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09427-19

Organization: San Miguel Electric Cooperative, Inc. (San Miguel)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09951-24

Organization: Full Circle Solutions, Incorporated

Commenter Type: Beneficial User
33

Comment Number: EPA-HQ-RCRA-2009-0640-10017-11

Organization: Salt River Project (SRP)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-05827-2

Organization:

Commenter Type: Private Citizen, P.E.

Comment Number: EPA-HQ-RCRA-2009-0640-06860-13

Organization: South Carolina Chamber of Commerce, Environmental Technical Committee

Commenter Type: Trade Association

Comment: NDEQ’s permit program allows for alternative liner design demonstrations 

that are equivalent to the requirements for municipal solid waste landfills under 40CFR Part 258 

and believes this is a reasonable and protective approach in states that have permit programs that 

adopt these same requirements.

Comment Number: EPA-HQ-RCRA-2009-0640-07533-36

Organization: Nebraska Department of Environmental Quality (NDEQ)

Commenter Type: State Government

Comment: Allow alternatives to composite liners when site specific characteristics 

support such alternatives. 

Comment Number: EPA-HQ-RCRA-2009-0640-06424-11

Organization: Garrett & Moore, Inc.

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-10017-29

Organization: Salt River Project (SRP)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-03444-7

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-06410-58

Organization: Anonymous

Commenter Type: Anonymous

Comment Number: EPA-HQ-RCRA-2009-0640-10017-29
34

Organization: Salt River Project (SRP)

Commenter Type: Electric Utility Company

Comment: Allow for the consideration of alternative liner systems that provide 

equivalent protection of human health and the environment.

Comment Number: EPA-HQ-RCRA-2009-0640-06832-27

Organization: SCANA Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09358-7

Organization: Interstate Power and Light Company (IPL) and Wisconsin Power and Light 

Company (WPL)

Commenter Type: Electric Utility Company

Comment: A demonstration made to Washington State and Lewis County of the 

adequacy of an alternative liner clearly demonstrates that this approach is protective of 

groundwater and that a composite liner is not the only way to protect groundwater and should not 

be the only default liner required under the CCR landfill requirements. The final rule should 

include the flexibility to use alternatives to composite liners that are demonstrated to achieve the 

same long-term performance standards.

Comment Number: EPA-HQ-RCRA-2009-0640-07048-12

Organization: TransAlta Centralia Generation

Commenter Type: Electric Utility Company

Comment: EPA should consider allowing alternate liners which are as effective as the 

proposed composite liners for landfills and surface impoundments. This would allow flexibility 

to site operators and provide the same protection for management of CCRs in landfills and 

surface impoundments.

Comment Number: EPA-HQ-RCRA-2009-0640-06917-29

Organization: Texas Commission on Environmental Quality (TCEQ)

Commenter Type: State Government

Comment: There should be a process for approval of alternative liner systems with the 

flexibility to match site specific conditions and material to be stored.

Comment Number: EPA-HQ-RCRA-2009-0640-06865-23

Organization: Constellation Energy
35

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09349-13

Organization: Santee Cooper

Commenter Type: Electric Utility Company

Comment: The CCR proposed rules should provide for alternate liner systems or 

variances from liner installation at locations where local geology or hydrogeology preclude the 

contamination of groundwater resources by leachate from the solid waste facility

Comment Number: EPA-HQ-RCRA-2009-0640-10166-16

Organization: Consumers Energy Company

Commenter Type: Electric Utility Company

Comment: EPA should provide for an engineering standard that can be met by facilities 

as a variance from leachate collection and composite liner requirements identified under Subpart 

C or D regulation.

Comment Number: EPA-HQ-RCRA-2009-0640-08225-19

Organization: Minnesota Power (ALLETE)

Commenter Type: Electric Utility Company

Comment: ASTSWMO would support allowing facilities to use alternative designs. 

Such flexibility would certainly be warranted if a State required or approved design differs from 

the federal requirements, yet is demonstrated to provide equivalent or greater performance.

Comment Number: EPA-HQ-RCRA-2009-0640-08787-40

Organization: Association of State and Territorial Solid Waste Management Officials 

(ASTSWMO)

Commenter Type: State Government

Comment: MassDEP recommends that alternative designs be based on performance 

equivalent to the specified standard design. The Massachusetts regulations include a provision 

allowing for review and approval of alternative designs as long as the design will achieve 

equivalent or superior performance to the standard design for the life of facility operations, 

closure and post -closure period. The equivalent design must use methodologies, materials and 

technologies that are clearly demonstrated to have been successful in similar applications and 

can use acceptable QA/QC methods to monitor construction and performance. 
36

Comment Number: EPA-HQ-RCRA-2009-0640-08251-12

Organization: Massachusetts Department of Environmental Protection

Commenter Type: State Government

Comment: EPA’s final rule should allow alternative liner designs at CCR disposal 

facilities. GCLs have been used successfully for 25 years as an alternate to compacted clay in 

both Subtitle C and Subtitle D landfill composite liner systems.

Comment Number: EPA-HQ-RCRA-2009-0640-04523-1 & 2

Organization: Brantley Engineering, LLC

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-05828-1

Organization: Provost & Pritchard Consulting Group

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-05929-1

Organization: Schnabel Engineering

Commenter Type: Other Company

Comment: The Subtitle D rule should allow for alternative liner systems to be approved 

by a qualified state program where the alternate liner can be shown as equally or more protective 

than a composite liner detailed in the existing proposal. For example a geosynthetic clay liner 

can perform equally as well as a flexible membrane composite liner in many geologic settings.

Comment Number: EPA-HQ-RCRA-2009-0640-07047-29

Organization: Great River Energy

Commenter Type: Electric Utility Company

Comment: It is absolutely necessary that any Subtitle D option allow for the usc of 

alternative liner systems for CCR disposal facilities. Alternative liner systems can provide equal 

if not more protection to groundwater, and there is no reason why these alternate, but equally 

protective systems, should not be available under the regulations. Depending on the location and 

physical characteristics of a CCR disposal facility, there are a range of liner systems that may be 

available to meet the applicable groundwater standards at the point of compliance. By 

establishing performance standards, this would give flexibility to tailor a system to meet the sitespecific characteristics of an individual disposal unit. These would include topographical, 

geological, climatological, and hydrological characteristics. EPA should not limit alternative 
37

liner design systems and deny owners/operators the ability to utilize systems that are equally or 

more protective as the composite liner system proposed in the Subtitle D options. Additionally, 

due to the significant volume of clay that is needed to line a facility, as well as the likelihood that 

other units would need the same materials in the same timeframe, there may be an insufficient 

supply of clay and/or it may be difficult to transport the needed volume of clay to the site.

Comment Number: EPA-HQ-RCRA-2009-0640-06833-20

Organization: Dominion Resources Services, Inc.

Commenter Type: Electric Utility Company

Comment: Based on the technical information presented, CETCO requests that EPA's 

final rule allow GCLs as an alternative to the low-permeability soil component underneath the 

FML for both the proposed RCRA Subtitle C and Subtitle D composite liner options. GCLs 

have become the state of the practice for waste containment facilities. EPA research has shown 

that GCLs provide equivalent or superior performance compared with compacted clay liners.

Comment Number: EPA-HQ-RCRA-2009-0640-06195-1

Organization: CETCO

Commenter Type: Other Company

Comment: The proposed regulations do not provide sufficient flexibility to consider 

alternative liners, leachate management methods, or final covers to accommodate variables in 

local conditions such as soil types, depth to groundwater, distance from surface water, and 

annual precipitation. The prescriptive one-size-fits-all approach unnecessarily ties the hands of 

state regulators and prevents them from tailoring permits to match the landfill design 

requirements to actual physical circumstances. For example, many aspects of the design 

imposed in the proposed regulation may be unnecessary in areas where local conditions provide 

an adequate and preferred degree of natural protection.

Comment Number: EPA-HQ-RCRA-2009-0640-06254-23 & EPA-HQ-RCRA-2009-0640-

06912-8

Organization: Sunflower Electric Power Corporation

Commenter Type: Electric Utility Company

Comment: The CCR proposed rules should provide for flexibility in design and 

construction. Performance-based standards should be allowed to supplement default, prescribed 

engineering standards.
38

Comment Number: EPA-HQ-RCRA-2009-0640-08840-18

Organization: Electric Power Generation Association

Commenter Type: Trade Association

Comment Number: EPA-HQ-RCRA-2009-0640-10166-15

Organization: Consumers Energy Company

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08850-13

Organization: Lansing Board of Water & Light (BWL)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08853-12

Organization: Lower Colorado River Authority (LCRA)

Commenter Type: Electric Utility Facility

Comment Number: EPA-HQ-RCRA-2009-0640-08865-8

Organization: Geosyntec Consultants

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-09239-68

Organization: Prairie State Generating Company, LLC (PSGC)

Commenter Type: Electric Utility Company

Comment: It is critical that any rule allow flexibility in liner designs. Alternative liner 

designs can be just as protective and more cost-effective in many cases. For example, we have 

demonstrated that an engineered geo-composite liner (manufactured clay & synthetic composite 

mat) can be as effective as a standard compacted clay & synthetic liner. We have also 

demonstrated that in many cases a simple clay liner, or even low permeability natural soils or 

impermeable rock formations, can provide the necessary protection, especially in arid states with 

no shallow or drinkable groundwater. We strongly oppose the concept of a "one-size fits all" 

prescriptive national liner standard, since such an approach would be arbitrary and completely 

ignore critical technical considerations such as waste characteristics, local climate, geology, 

native soil permeability, depth to groundwater, presence or absence of down-gradient receptors, 

leachable contaminants in the waste material, the mitigating effects of natural attenuation, etc. 

These are all important engineering and design considerations and illustrate why state permitting 

engineers, geologists and hydrologists are in the best position to determine what is technically 
39

necessary and appropriate for a given disposal facility. It is important that any CCR rule 

finalized by EPA allow for alternative liner designs that factor in local circumstances. To do 

otherwise would be arbitrary and capricious.

Comment Number: EPA-HQ-RCRA-2009-0640-08253-8

Organization: Xcel Energy

Commenter Type: Electric Utility Company

Comment: Geosyntec supports the use of GCLs as an alternative to a compacted clay 

liner at CCR disposal sites. Geosyntec’s experience at over one hundred waste containment liner 

system design and construction projects indicates that, when properly designed and constructed, 

GCLs can provide equivalent performance to CCLs.

Comment Number: EPA-HQ-RCRA-2009-0640-08865-8

Organization: Geosyntec Consultants

Commenter Type: Other Company

Comment: It doesn't make sense for EPA to advocate prescriptive designs for 

applications where multiple technologies are available and perform similarly for two reasons;

first, this stifles the development of newer, more effective and potentially less costly technology 

alternatives because it limits the opportunity for their eventual application. This seems to be 

counter to what EPA's mandate should be. Second, it places all of the risk, should the 

technology that EPA supports ultimately prove inadequate, on EPA. The USEPA should be 

setting performance based standards and spending their resources evaluating the proposed 

approaches but letting the marketplace deliver solutions that are first effective, then cost effective 

for those who have to pay the bill.

Comment Number: EPA-HQ-RCRA-2009-0640-05798-1

Organization: Anonymous

Commenter Type: Environmental Consultant

Comment: As landfill designers, we have successfully designed, permitted, and 

constructed numerous Subtitle D Landfill Sites utilizing geosynthetic clay liners with site soils, 

and believe that the proposed coal ash landfill regulations should include language to incorporate 

equivalent or superior liner designs.

Comment Number: EPA-HQ-RCRA-2009-0640-05825-1

Organization: TriAD Environmental Consultants, Inc.
40

Commenter Type: Other Company

Comment: I have operated and designed many landfill cells that use alternative liner 

designs at Subtitle C and D facilities and consider these should also allowed at CCR disposal 

facilities. A common alternative liner design involves the use of a geosynthetic clay liner (GCL) 

in place of the compacted clay layer underneath the FML. There is a significant body of 

independent research and field performance data (much of it from USEPA studies) which shows 

that GCLs can outperform compacted clay liners.

Comment Number: EPA-HQ-RCRA-2009-0640-05826-1

Organization: Vista Consultants

Commenter Type: Other Company

Comment: It is my experience and professional opinion that alternative liner design 

involving the use of a geosynthetic clay liner (GCL) in place of the compacted clay layer 

underneath the FML should be allowed.

Comment Number: EPA-HQ-RCRA-2009-0640-05867-1

Organization: Not Given

Commenter Type: Professional Engineer

Comment: Having designed liner systems for solid waste and incinerator ash monofills 

for the past 20 years, I have found that allowing the designer to select the appropriate soil 

component of the liner system is by far the best solution. Compacted soil liners are difficult to 

properly design and construct. Many sites don't have adequate soil, so either have to import the 

entire compacted soil layer or amend site soils with sodium bentonite. Importing of soil or 

amending soil is expensive and can be avoided using geosynthetic clay liners (GCLs).

Also, the depth to groundwater can be shallow at some sites. By using a GCL an owner can gain 

two feet of air space without sacrificing the performance of the liner system. This saves valuable 

air space which will lengthen the life of a facility.

Comment Number: EPA-HQ-RCRA-2009-0640-05927-1

Organization: Parametrix

Commenter Type: Other Company

Comment: The requirement in Subtitle D mandating a minimum of 2 feet of compacted 

clay in liner construction should be amended to allow for synthetic equivalents and/or alternative 

liner designs that can be proven to be an equivalent in performance to the proposed 2 feet of clay 
41

overlain by a flexible membrane liner.

Comment Number: EPA-HQ-RCRA-2009-0640-06041-5

Organization: SKB Environmental, Inc (SKB)

Commenter Type: Other Company

Comment Number: EPA-HQ-RCRA-2009-0640-06251-4

Organization: We Energies

Commenter Type: Electric Utility Company

Comment: Alternative liner designs should be available based on a specific performance 

standard.

Comment Number: EPA-HQ-RCRA-2009-0640-10732_DEN-044-4

Organization: Platte River Power Authority

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10752_DEN-064-2

Organization: Xcel Energy

Commenter Type: Electric Utility Company

Comment: Alternatives should be recognized, such as a geosynthetic clay liners (GCL). 

Alternative liner designs based upon specific performance standards referenced in 40 CFR Part 

258.40 should also be recognized.

Comment Number: EPA-HQ-RCRA-2009-0640-06723-21

Organization: West Virginia Department of Environmental Protection (WVDEP)

Commenter Type: State Government

Comment: The Subtitle D rule should allow for the use of alternative liner systems for 

CCR disposal units. In some regions of the country, the proposed composite liner system is 

unnecessary to ensure protection of groundwater. There are alternative liner systems that can 

provide equal if not more protection to groundwater and there is no reason why these alternate, 

but equally protective systems, should not be allowed.

Comment Number: EPA-HQ-RCRA-2009-0640-08864-7

Organization: JEA

Commenter Type: Electric Utility Facility

Comment Number: EPA-HQ-RCRA-2009-0640-09274-17

Organization: RRI Energy Inc.
42

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09536-9

Organization: Tennessee Valley Authority

Commenter: John W. Myers

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09885-27

Organization: Progress Energy, Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06308-12

Organization: NRG Energy Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-08270-5

Organization: Cliffs Natural Resources Inc. (Cliffs)

Commenter Type: Other Company

Comment: In many cases, local and/or economical sources of suitable clay liner material 

are not available, resulting in higher project costs.

Comment Number: EPA-HQ-RCRA-2009-0640-05867-2

Organization:

Commenter Type: Private Citizen, P.E.

Comment: New surface impoundments should allow for the use of performance based 

alternate liner systems instead of specifying a given technology. This flexibility in the CCR rule 

would allow a site specific design of appropriate liners which could reflect site specific 

conditions. Different locations will have different site specific considerations, including depth to 

groundwater, which will need to be factored into the design standards. Even in certain locations 

where potential risks to groundwater are greater, many alternate liner systems can meet or 

exceed the performance standards proposed in the rule. This option should also allow a company 

employed Registered Professional Engineers (“PE’) and or hydrologists to accomplish 

compliance certifications; not just third party PEs or hydrologists.

Comment Number: EPA-HQ-RCRA-2009-0640-06299-17

Organization: MidAmerican Energy Holdings Company (MidAmerican)

Commenter Type: Electric Utility Company
43

Comment: We strongly support the rule including flexibility for an applicant to make a 

demonstration that an alternative liner design would also be acceptable. This might be a 

compacted clay liner, such as the four foot thick compacted clay liner in Wisconsin rules, but it 

might also be used by an applicant that chooses to demonstrate the effectiveness of composite 

liners that include geosynthetic clay liners in conjunction with soils that do not meet clay liner 

requirements. Other possibilities might also arise. Given the diversity of soils across the US and 

the potential for new geosynthetic or other products to be developed in the future, provisions 

need to be included in the rule to allow their use if justified.

Comment Number: EPA-HQ-RCRA-2009-0640-06416-54

Organization: Wisconsin Department of Natural Resources (WI DNR) and Public Service 

Commission of Wisconsin (WI PSC)

Commenter Type: State Government

Comment: EPA should allow alternative liner designs at CCR disposal facilities. The 

proposed rule currently does not allow for any deviation from the liner requirements for CCR 

units regardless of site specific conditions, EPA appropriately asks whether the RCRA subtitle D 

option “should allow facilities to use an alternative design for new disposal units” provided a 

registered PE or hydrologist certifies that an alternate design system would “ensure that the 

appropriate concentration values for a set of constituents typical of CCRs will not be exceeded in 

the uppermost aquifer at the relevant point of compliance – i.e., 150 meters from the unit 

boundary downgradient from the unit, or the property boundary if the point of compliance (i.e., 

the monitoring well) is beyond the property boundary.” Id. at 35202- 03. There is no question 

that alternate liner systems must be allowed under the Subtitle D program.

Comment Number: EPA-HQ-RCRA-2009-0640-06198-8

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06203-13

Organization: Arizona Public Service Company (APS)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06863-41

Organization: Avista Corp.

Commenter Type: Electric Utility Company
44

Comment Number: EPA-HQ-RCRA-2009-0640-06956-13

Organization: Tri-State Generation & Transmission

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09536-9

Organization: Tennessee Valley Authority

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09713-11

Organization: Indianapolis Power & Light Company (IPL)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09885-27

Organization: Progress Energy, Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment Number: EPA-HQ-RCRA-2009-0640-09713-11

Organization: Indianapolis Power & Light Company (IPL)

Commenter Type: Electric Utility Company

Comment: Most states currently allow alternative designs under their RCRA subtitle D 

programs and that the experience of the municipal solid waste management community (i.e., 

regulators, owners, operators, and the public) on the use of alternative liners has been very 

positive. In particular, Geosyntec supports the use of GCLs as an alternative to a compacted clay 

liner at CCR disposal sites. Geosyntec’s experience at over one hundred waste containment liner 

system design and construction projects indicates that, when properly designed and constructed, 

GCLs can provide equivalent performance to CCLs.

Comment Number: EPA-HQ-RCRA-2009-0640-08865-8

Organization: Geosyntec Consultants

Commenter Type: Other Company

Comment: A liner design constructed from alternative materials (as compared to the 

prescriptive proposed composite liner system under the design criteria of 40 C.F.R. § 257.70) 

that is equally protective of groundwater must be allowed. EPA already acknowledges that there 
45

are alternative liner systems that can provide equal, if not greater, protection to groundwater. 

Indeed, EPA has consistently recognized throughout the Bevill Amendment regulatory 

determination process that, given the vastly different site-specific characteristics of CCR disposal 

units across the country, there is not a “one-size-fits-all” approach when it comes to regulatory 

design standards for these units. Thus, there is no good reason why alternate – but equally 

effective – liner systems should not be available for utility CCR unit designs.

Comment Number: EPA-HQ-RCRA-2009-0640-06398-40

Organization: Duke Energy

Commenter Type: Electric Utility Company

Comment: The alternative liner design provision within 40 CFR 258.40(a)(1) is an 

essential element of Alaska's Subtitle D regulatory program because of a lack of soil that meets 

the hydraulic conductivity requirements of the prescribed composite liner in 40 CFR 258.40(b). 

It will be impossible to build a CCR landfill in Alaska in compliance with the proposed design 

requirements unless alternative liner designs are allowed.

Comment Number: EPA-HQ-RCRA-2011-0392-0196-3 & EPA-HQ-RCRA-2009-0640-

06409-5

Organization: State of Alaska

Commenter Type: State Government

Comment: It is recommended that technical equivalency [of alternative liners] be 

demonstrated not only on the basis of various hydraulic parameters, such as flow rate or flux, but 

also on physical / mechanical parameters, such as differential settlement and slope stability, and 

construction issues, such as puncture resistance, sub grade conditions, and weather constraints. 

The overall design, including liner cross section, specifications, and CQC and CQA activities 

during installation must provide for technical equivalency.

Comment Number: EPA-HQ-RCRA-2009-0640-09349-13

Organization: Santee Cooper

Commenter Type: Electric Utility Company

Comment: Alternative liner systems are important precisely because they meet, and can 

exceed, EPA standards in protecting human health and the environment. Furthermore, they often 

reflect and address state and regional geology.

Comment Number: EPA-HQ-RCRA-2009-0640-10498-13
46

Organization: Florida Electric Power Coordinating Group, Inc. (FCG)

Commenter Type: Electric Utility Company

Comment: EPA must recognize that alternative liner systems can be equally as protective 

as, or more protective than, composite liner systems. These alternative liner systems have been 

approved by EPA as an acceptable alternative to the composite liner for MSWLFs, which are

more likely to pose a greater threat to human health and the environment than CCR landfills.

Florida’s double HDPE geomembrane liner system (“double liner”) is a prime example of one of 

these alternative liner systems. 

4

[Florida’s double liner system is different from EPA’s double 

liner system requirements for hazardous waste landfills, required by RCRA § 3004(o)(4)(A), and 

detailed in 40 C.F.R. sections 264.301(c) and 264.302. ] Under its EPA-approved MSWLF 

program, FDEP permits the use of a double liner as an alternative to the composite liner.

This liner system was critically evaluated in the early- to mid-1990s by the Florida Department 

of Environmental Protection (“FDEP”), a Technical Advisory Group formed by FDEP, and EPA. 

EPA has approved Florida’s Subtitle D MSWLF program, which includes this liner system 

option.

Comment Number: EPA-HQ-RCRA-2009-0640-06300-30

Organization: Southern Company on behalf of itself and its four subsidiaries: Alabama Power 

Company, Georgia Power Company, Gulf Power Company, and Mississippi Power Company

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10497-9

Organization: Seminole Electric Cooperative, Inc. (Seminole)

Commenter Type: Electric Utility Company

 

4 Florida has concluded that, if constructed in accordance with Florida’s Rule 62-701.400(3)(c), F.A.C., a 

double liner is more protective of the environment than a composite liner installed in accordance with 

Rule 62-701.400(3)(b), F.A.C. Thus, in Florida, EPA’s proposed composite liner would be less 

protective than the liner systems currently in use. Florida has studied its EPA-approved double liner at 

least four times, each time finding the double liner more protective than a composite liner. EPA has failed 

to provide any mechanism allowing states like Florida to approve sound alternative liner systems. It 

appears also that EPA failed to even consider Florida’s technical demonstrations or provide its own 

evidence contradicting them. For these reasons, EPA’s adoption and mandate of its proposed composite 

liner requirement, to the exclusion of any alternatives, is arbitrary and capricious. (See Motor Vehicles 

Mfrs. Ass’n v. State Farm Mutual Auto. Ins. Co., 463 U.S. 29, 43 (1983).)
47

Comment Number: EPA-HQ-RCRA-2009-0640-10498-13

Organization: Florida Electric Power Coordinating Group, Inc. (FCG)

Commenter Type: Electric Utility Company

Comment: Soil/clay in adequate amounts or with adequate characteristics is not available 

for use in the proposed composite liner.

Comment Number: EPA-HQ-RCRA-2009-0640-06846-10 & 12

Organization: Florida Department of Environmental Protection (FDEP)

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09282-10 & 12

Organization: North Carolina Department of Environment and Natural Resources

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-10324-15

Organization: Public Service Company of New Hampshire (PSNH)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10498-13

Organization: Florida Electric Power Coordinating Group, Inc. (FCG)

Commenter Type: Electric Utility Company

Comment: The Salt River Project‘s (“SRP”) Coronado Generating Station, located in St. 

John‘s Arizona, has climatic conditions favorable for CCR disposal. The facility operates a State 

of Arizona permitted FGD surface impoundment and ash landfill. The regional aquifer is located 

more than 300 feet below the bottom of the FGD impoundment. The average annual rainfall for 

this area is less than 12 inches. The FGD impoundment and ash landfill are located on the 

Chinle Formation, which consists of 150-200 feet thick sequence of bentonitic clay, shale, and 

siltstone, with a hydraulic conductivity of 1x10-7to 1x10-9cm/sec. The permeability and 

thickness of the Chinle unit, along with the depth to groundwater, serve as BADCT for the 

ADEQ APP. The FGD impoundment has been operating with a natural clay liner for over 30 

years. Contamination of the regional drinking water aquifer has not occurred in that time frame. 

Site specific modeling of groundwater flow over an operational period of 10,000 years indicates 

that the FGD impoundment has not, and will not, contaminate the regional groundwater under 

scenarios used in EPA‘s Risk Assessment.

Comment Number: EPA-HQ-RCRA-2009-0640-10017-12
48

Organization: Salt River Project (SRP)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: SRP‘s Navajo Generating Station located on the Navajo Nation land in 

Arizona operates a CCR landfill for all of its CCRs destined for disposal (i.e., fly ash, bottom 

ash, and de-watered FGD material). The CCR landfill is located in a dry climate with an average 

annual rainfall of less than 8 inches. The depth to groundwater in the Navajo Sandstone 

Formation is 800-900 feet below the bottom surface of the landfill. Neutron logging is 

conducted at the landfill to detect any moisture in the vadose zone. Groundwater monitoring is 

conducted down-gradient of the unit. The Navajo Sandstone Formation forms the principal 

regional aquifer system for the area.

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: Alternative liners may be acceptable in some geographic settings. Coal fly 

ash has extremely low moisture content at the time of collection by the ESP or baghouse. As a 

result, it has a moisture deficit, meaning that it will retain a certain volume of water when 

exposed to atmospheric conditions. High calcium fly ash, such as that associated with some 

subbituminous and lignite coals burned in the western U.S., also undergoes hydration reactions 

on exposure to water, further utilizing excess moisture. Placing ash in layers designed to utilize 

any excess moisture, and then covering with a low permeability cap or a water balance cap, can 

effectively minimize percolation through the ash. EPRI performed a field and modeling study of 

this concept at a western power plant burning subbituminous coal. The results supported the low 

percolation potential for the site, and were used to help obtain state approval for an alternative to 

the standard composite liner requirement.

Comment Number: EPA-HQ-RCRA-2009-0640-09765-56

Organization: Electric Power Research Institute (EPRI)

Commenter Type: Trade Association

Comment: Eastman owns and operates a permitted hazardous waste landfill as well as an 
49

industrial solid waste landfill permitted under Tennessee solid waste regulations. Our 

experiences with the construction and quality assurance of both Subtitle C double liner systems 

meeting minimum technology requirements under 40 CFR 264.301 and Subtitle D composite 

liner systems meeting or equivalent to MSW standards under 40 CFR 258 demonstrate the value 

of and enhanced compliance assurance offered by alternate designs that are demonstrated to be 

equivalent or superior to a performance standard. For example, this proposed rule requires a 

composite liner that includes two feet of clay compacted to achieve a hydraulic conductivity of 1 

x 10-7centimeters per second. The clay soils native to eastern Tennessee are ill-suited for 

compaction to this hydraulic conductivity. In order to achieve this performance, significant 

engineering and construction effort must be expended. In addition, substantial quality control 

and quality assurance must also be employed to assure compliance with this performance 

standard is achieved. However, Tennessee's industrial landfill regulations allow facilities to use 

liners that are demonstrated to provide equivalent or superior performance. As a result, Eastman 

as well as other industrial landfills in the State have demonstrated that alternate designs which 

substitute a flexible membrane liner (FML) for the clay component of a composite liner system 

achieve compliance with the standards. Furthermore, FMLs can more consistently and more 

easily be shown to meet construction quality assurance requirements due to the manufacturing 

quality controls imposed by the industry as well as the established and rigorous testing protocols 

to which FMLs can be subjected (for example, leak testing of 100% of all welded seams). 

Eastman’s experience has shown that construction of a composite liner consisting of FMLs is 

approximately one-third the cost of constructing a composite liner consisting of an FML and 

clay. Eastman therefore supports allowing facilities to use alternate designs for liner systems 

under both the Subtitle C and Subtitle D options. 

Comment Number: EPA-HQ-RCRA-2009-0640-06880-7

Organization: Eastman Chemical Company (Eastman)

Commenter Type: Other Company

Comment: Even in locations where potential risks to groundwater are greater, there are 

alternate liner systems that can achieve the same level of protection as the composite liner 

system proposed by EPA. For example, geosynthetic clay liner (“GCL”) or similar systems can 

meet or exceed the performance standards of clay liners and certainly are equivalent or superior 

in some circumstances to two-feet of compacted soil in the lower component of the composite 
50

liner systems proposed under the Subtitle D option. Therefore, in many circumstances, a liner 

system using the GLC in lieu of the two-feet of compacted soil readily enables a CCR disposal 

unit to meet the applicable groundwater monitoring standards. Depending on the location and 

physical characteristics of the disposal unit, there are a range of liner systems that may be 

available to meet the applicable groundwater standards at the point of compliance. EPA should 

not limit alternative liner design systems and deny owners/operators the ability to utilize systems 

that are equally or more protective as the composite liner system proposed in the Subtitle D 

option.

Comment Number: EPA-HQ-RCRA-2009-0640-06203-13

Organization: Arizona Public Service Company (APS)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06956-13

Organization: Tri-State Generation & Transmission

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09885-27

Organization: Progress Energy, Inc.

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: Geosynthetic clay liners would be an alternative to the prescriptive compacted 

clay component of the composite liner in the rule. Since GCLs are expected to contribute the 

lowest leakage, lower than compacted clay, and can help achieve the EPA mission to protect 

human health and the environment, we recommend that GCLs be allowed as an alternative liner 

component.

Comment Number: EPA-HQ-RCRA-2009-0640-11174_CHI-002-2

Organization: Geosynthetic Materials Association (and CETCO)

Commenter Type: Trade Association

Comment: In light of the fact that the locations of CCR surface impoundments vary 

widely in terms of their topographical, geological, climatological and hydrological 

characteristics, any liner requirement must provide some degree of flexibility to account for the 
51

site-specific characteristics associated with those impoundments. Otherwise, the same concerns 

with over-regulation that the Agency described in its August, 1993 final regulatory program will 

resurface in the Subtitle D option. Therefore, the Agency should provide an owner/operator the 

ability to utilize alternative liner systems that are equally or more protective as the composite 

liner system proposed in the Subtitle D option for surface impoundments, as long as their use is 

approved by the appropriate state regulatory agency.

Comment Number: EPA-HQ-RCRA-2009-0640-06827-13

Organization: Oklahoma Gas and Electric Company (OG&E)

Commenter Type: Electric Utility Company

Comment: EPA should allow alternative liner systems based on individual site conditions 

or based on adequate State program determinations.

Comment Number: EPA-HQ-RCRA-2009-0640-08247-2

Organization: Tucson Electric Power Company

Commenter Type: Electric Utility Company

Comment: We recommend that the regulations require the use of a geomembrane lining 

system (geomembranes and\or geosynthetic clay liners with membranes) as this system has been 

demonstrated (by EPA) to be a most effective barrier methodology, regardless of the 

classification of the materials (hazardous, non-hazardous or designated for beneficial re-use).

Comment Number: EPA-HQ-RCRA-2009-0640-05745-1

Organization: BTL Group of Companies

Commenter Type: Other Company

Comment: EPA should define and require a ‘composite liner’ consisting of two 

components: An upper component consisting of a flexible membrane liner (FML), and a lower 

component consisting of a geosynthetic clay liner. If ‘composite liner’ is not redefined to 

include a lower component GCL, then the allowance of an alternative liner design/system should 

be included. 

Comment Number: EPA-HQ-RCRA-2009-0640-05235-1

Organization: Propex Geosynthetics

Commenter Type: Other Company

Comment: EPA expresses reluctance in allowing alternative liners for new CCR facilities 

on page 75 FR 35203. This reluctance appears to be due, in part, to the expectation that owners 
52

would propose a soil liner alone in place of the entire prescribed composite liner. We agree that 

a soil liner alone would not be as protective as the prescribed composite liner system, and should 

therefore not be considered an adequate substitute. We agree that an upper FML component is 

essential. However, there are other technically feasible alternatives to the lower 2-ft compacted 

soil component that should be considered. Specifically, use of a geosynthetic clay liner (GCL) 

below the FML should be considered as an equivalent substitute for a compacted soil 

component. GCLs are factory-manufactured mats consisting of 0.75 lb/ft2 of sodium bentonite 

clay between two geotextile layers, with a hydraulic conductivity of 5 x 10-9 cm/sec per ASTM 

D5887. Due to their low hydraulic conductivity, GCLs are frequently used as a substitute for 

two-foot thick compacted soil liners in composite liner systems of many municipal solid waste 

landfills (MSWLFs). Field evidence has shown that composite liners with GCLs function 

equally well as, or better than composite liners with a compacted soil component (Bonapaiie et 

al. 2002, Bareither et al. 2010).

Comment Number: EPA-HQ-RCRA-2009-0640-06524-1

Organization: CETCO and University of Wisconsin Madison

Commenter Type: Other Company

Comment: The regulations should include an allowance for alternative liner 

designs/systems. Under both Subtitles D and C, alternative designs using geosynthetics have 

frequently and consistently been proven to be cost effective solutions to situations where natural 

soils and aggregates are not readily available. The benefits and successes of utilizing 

geosynthetic systems in containment systems have been well documented by the technical 

materials and reports by the EPA. Geosynthetics have been tested and successfully evaluated in 

great detail over a long period of use in a extremely wide range of applications by EPA.

Comment Number: EPA-HQ-RCRA-2009-0640-06552-1

Organization: Agru America, Inc. (Agru)

Commenter Type: Other Company

Comment: A performance standard for liners must be established. Performance standards 

provide facilities with flexibility while ensuring that appropriate safeguards are in place. 

Providing an alternative standard to address circumstances where the requirement is highly 

dependent on site-specific conditions is appropriate when mechanisms are in place to ensure that 

the alternative is protective of health and the environment. To ensure that the alternative 
53

standard is protective, the standard can be accompanied by notification and documentation 

requirements. Certification by a registered professional provides an appropriate level of 

certainty that the performance standard is being met. In addition, notification would be provided 

to the state and the public such that enforcement could be pursued if necessary. Providing an 

alternative like the one it is proposing allows facilities the flexibility to account for site 

conditions. 

Comment Number: EPA-HQ-RCRA-2009-0640-06529-40

Organization: NiSource Corporate Services

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06532-34

Organization: Southern Illinois Power Cooperative

Commenter Type: Electric Utility Company

Comment: For the geological and climatic conditions encountered in Kansas this 

proposed [composite liner] language is limiting and would not allow designs which can be 

equally protective while having the advantage of being sustainable indefinitely into the future. 

Capillary barrier designs using in-situ materials and geosynthetic clay liners have been used 

successfully in Kansas landfills located in areas of low precipitation. Other liner designs 

consisting of compacted clay have been adequately protective as demonstrated by years of 

groundwater monitoring in areas of eastern Kansas with higher precipitation and more shallow 

groundwater. A composite Subtitle D liner is clearly not needed to protect groundwater or 

surface water in all geologic and climatic scenarios. States should have the flexibility to review 

and approve of alternative liner designs that will provide adequate protection.5

 

5 Therefore, Kansas requests that paragraph (a)(I) of this section be modified to allow alternate 

designs as follows:

1) With a composite liner, as defined in paragraph (a)(2) of this section and a leachate collection 

system that is designed and constructed to maintain less than a 30-cm depth of leachate over the 

liner or an alternate design approved by the Director of an approved state that demonstrates that 

leachate will be contained or managed in a manner that is protective of ground water and 

surface water. The design of the composite liner and leachate collection system must be prepared 

by, or under the direction of, and certified by an independent registered, professional engineer. 

(modification in italics)
54

Comment Number: EPA-HQ-RCRA-2009-0640-03444-34

Organization: Kansas Department of Health and Environment

Commenter Type: State Government

Comment: The proposed language is restrictive and would not allow designs which can 

be equally protective of groundwater and surface water. Other alternate liners have been used 

successfully throughout the country and provisions to allow alternate liners need to be 

incorporated. A composite Subtitle D liner is clearly not needed to protect groundwater or 

surface water in all geologic and climatic scenarios. States should have the flexibility to review 

and approve alternative liner designs that will provide adequate protection as allowed under part 

258 for sanitary landfills. Therefore, we request that paragraph (a)(1) of this section be modified 

to allow alternate designs

Comment Number: EPA-HQ-RCRA-2009-0640-09284-21 & 32

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment Number: EPA-HQ-RCRA-2009-0640-09337-35 & 36

Organization: Arizona Department of Environmental Quality (ADEQ)

Commenter Type: State Government

Comment: For new CCR landfills and lateral expansions, there should be provisions for 

alternative landfill liner systems that have been demonstrated as acceptable under the state 

municipal waste landfill experiences per state. For new CCR surface impoundments and lateral 

expansions, there should be a process for approval of alternative liner systems. This should 

address the flexibility to match site specific conditions and material to be stored.

Comment Number: EPA-HQ-RCRA-2009-0640-06865-23

Organization: Constellation Energy

Commenter Type: Electric Utility Company

Comment: The regulations should provide performance, rather than prescriptive 

requirements to be met. Sites for storage of CCR vary according to physiographic province 

within a particular state, even more so across the entire United States. Design standards that may 

be suitable for one site may provide inadequate safety and environmental protection for another 

and may represent a significant overdesign for yet a third site. By establishing performance 

standards to be met, a framework allowing for innovation, incorporation of developing “best 
55

practices” and site--- specific solutions is promoted. This approach can result in solutions that 

are not only more cost---effective, but can also provide better protection of property and the 

environment, in view of the specific site conditions encountered. 

Comment Number: EPA-HQ-RCRA-2009-0640-06831-2

Organization: MACTEC Engineering and Consulting, Inc.

Commenter Type: Other Company

Comment: There should be state oversight for all disposal facility designs. Minnesota 

does an independent review of all facility designs prior to permit issuance. MPCA staff have 

approved alternative liner designs for disposal facilities if they are at least as protective as the 

USEPA's proposed composite liner system. Minn. R. 7035.2815, subp. 7(K) allows the 

commissioner to approve an alternative liner system design ... "The commissioner's approval 

shall be based on the ability of the proposed liner system to control leachate migration, meet 

performance standards, and protect human health and the environment." These landfill liners 

consist of a 1 foot of clay, 2 feet of clay, or a Geosynthetic clay liner overlain by a minimum 60 

mil HDPE liner.

Comment Number: EPA-HQ-RCRA-2009-0640-06838-7

Organization: Minnesota Pollution Control Agency (MPCA)

Commenter Type: State Government

Response: EPA agrees with the commenters and is allowing alternative composite liner 

designs for new CCR landfills, new CCR surface impoundments, lateral expansions, and retrofits 

of existing CCR surface impoundments, where the owner or operator provides certification by a 

qualified professional engineer that the alternative composite liner design meets the specified 

performance standard. Specifically, the alternative composite liner can consist of an alternative 

to the two feet of compacted clay with a hydraulic conductivity no greater than 1 x 10-7 cm/sec 

and a geomembrane upper component. The alternative lower component must be certified by a 

qualified professional engineer that the liquid flow rate through the lower component of the 

alternative composite liner is no greater than the liquid flow rate through two feet of compacted 

soil with a hydraulic conductivity of 1x10-7cm/sec. See section VI. F. 5. c. of the preamble to 

the final rule for a further discussion on alternative liners.

c. Use of a Composite Liner System Consisting of Two FMLs.
56

Comment: The clay soils native to eastern Tennessee are ill-suited for compaction to this 

hydraulic conductivity. In order to achieve this performance, significant engineering and 

construction effort must be expended. In addition, substantial quality control and quality 

assurance must also be employed to assure compliance with this performance standard is 

achieved. However, Tennessee's industrial landfill regulations allow facilities to use liners that 

are demonstrated to provide equivalent or superior performance. As a result, industrial landfills 

in the State have demonstrated that alternate designs which substitute a flexible membrane liner 

(FML) for the clay component of a composite liner system achieve compliance with the 

standards. Experience has shown that construction of a composite liner consisting of FMLs is 

approximately one-third the cost of constructing a composite liner consisting of an FML and 

clay. The commenter supports allowing facilities to use alternate designs for liner systems.

Comment Number: EPA-HQ-RCRA-2009-0640-06880-7

Organization: Eastman Chemical Company (Eastman)

Commenter Type: Other Company

Comment: Florida requires a double liner system. The double liner system consists of 

upper and lower 60-mil minimum average thickness HDPE geomembranes, with a primary 

leachate collection and removal system lying above the upper geomembrane designed to limit 

the leachate head to one foot above the liner during routine landfill operations after placement of 

initial cover, except in sumps and leachate collection trenches; and a leak detection and 

secondary leachate collection system between the upper and lower liners. The lower 

geomembrane must be placed directly on a subbase which is a minimum six inches thick, is free 

of sharp materials or any materials larger than one-half inch, and has a saturated hydraulic 

conductivity of less than or equal to 1 x 10-5cm/sec. A geosynthetic clay liner (GCL) with a 

hydraulic conductivity not greater than 1 x 10-7cm/sec may be used in place of the six-inch thick 

sub-base layer provided it is placed on a prepared subgrade which will not damage the GCL. 

Florida has concluded that, if constructed in accordance with Florida’s Rule 62-701.400(3)(c), 

F.A.C., the double liner system is more protective of the environment than a composite liner 

installed in accordance with Rule 62-701.400(3)(b), F.A.C. Thus, in Florida, EPA’s proposed 

composite liner would be less protective than the liner systems currently in use. Florida has 

studied its EPA-approved double liner at least four times, each time finding the double liner 

system more protective than a composite liner.
57

Comment Number: EPA-HQ-RCRA-2009-0640-10497-9

Organization: Seminole Electric Cooperative, Inc. (Seminole)

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10498-13

Organization: Florida Electronic Power Coordinating Group, Inc. (FCG)

Commenter Type: Electric Utility Company

Response: First, EPA does not agree that a composite liner consisting of two 30-mil 

FMLs will provide equivalent protection as a composite liner consisting of a GM and two feet of 

compacted soil, or an alternative composite liner such as a GM over a GCL. While FMLs have 

the advantages of extremely low rates of water permeation, the disadvantages of a composite 

liner consisting of two FMLs include leakage through occasional FML imperfections and 

punctures, potential for slippage along the interface between the FMLs, and FML embrittlement 

over time. Furthermore, a critical component of a composite liner is the compacted soil or GCL 

component beneath the GM layer which will impede the flow of liquid that may leak through a 

hole or defect in the GM. This added protection is not achievable using two FMLs for the 

composite liner system. Additionally, the potential exists for liquid transport through the FMLs 

through holes caused by punctures, tears, flawed seams, etc. If a puncture occurs, the puncture 

could compromise both FMLs and create a conduit for liquid flow to underlying permeable soil. 

Moreover, a liner system consisting of two FMLs in contact with each other poses the risk of 

creating a slip plane that may compromise the stability of the disposal unit (although EPA 

acknowledges that using textured GMs would reduce or eliminate this risk). These data are 

documented in EPA research. 

6

 Hence, the alternative liner design must consist of two parts, an 

upper GM component and a lower component other than a GM, that is certified by a qualified 

professional engineer to meet the performance criteria of today’s rule. 

Regarding the double liner system required in Florida and described above, while this 

double liner system provides the advantage of a leak detection system between the two GMs, the 

lower composite liner consisting of a 60-mil HDPE over six inches of soil with a saturated 

hydraulic conductivity of less than or equal to 1 x 10-5cm/sec is not equivalent to a GM over two 

feet of compacted soil with a hydraulic conductivity of less than or equal to 1 x 10-7cm/sec. To 

 

6

“Assessment and Recommendations for Improving the Performance of Waste Containment Systems.” 

http://www.epa.gov/nrmrl/pubs/600r02099/600r02099.htm
58

be hydraulically equivalent, soil with a hydraulic conductivity of 1 x 10-5cm/sec would need to 

be on the order of 100 times thicker than soil with a hydraulic conductivity of less than or equal 

to 1 × 10-7cm/sec. Similarly, a lower composite liner consisting of a 60-mil HDPE over a GCL 

with a hydraulic conductivity not greater than 1 x 10-7cm/sec would require a GCL thickness of 

24 inches to be equivalent to a GM over two feet of compacted soil with a hydraulic conductivity 

of less than or equal to 1 x 10-7cm/sec. Therefore, EPA is finalizing a requirement in today’s 

rule that the lower component of the required single composite liner must be either two feet of 

compacted soil with a hydraulic conductivity no greater than 1 x 10-7cm/sec or an alternative 

composite liner with a lower component that meets the performance standard described in 

section VI. F. 5. C of the preamble to the final rule. EPA did not propose a double liner system 

requirement and, while today’s requirements are minimum requirements, states may impose 

additional requirements in addition to today’s requirements; e.g., a leak detection system 

overlain by a GM, if the state deems additional requirements are necessary. 

d. Specific Use of Geosynthetic Clay Liners as an Alternative to the Composite Liner.

Comment: Giroud (1997) conducted an empirical study in his technical article 

"Equations for Calculating the Rate of Liquid Migration Through Composite Liners Due to 

Geomembrane Defects." The study yielded an equation that predicts the leakage rate from a 

composite liner with a defect in the geomembrane (e.g., installation damage). For a given size 

defect, the main factor controlling the leakage rate is the hydraulic conductivity of the lower soil 

component. Based on the study results, it shows that a composite liner with a geomembrane and 

GCL with a hydraulic conductivity of 10-7cm/s is expected to have a lower leakage rate than a 

composite liner with a geomembrane and a two foot compacted clay liner with a hydraulic 

conductivity of 1 x 10-7cm/sec. CETCO requests that EPA’s final rule allow GCLs as an 

alternative to the low-permeability soil component underneath the FML.

Comment Number: EPA-HQ-RCRA-2009-0640-06524-1

Organization: CETCO and University of Wisconsin Madison

Commenter Type: Other Company

Response: EPA has examined the performance of GCLs approved for use as alternatives 

to composite liners in municipal solid waste landfills.7 The EPA report titled “Assessment and 

 

7

 “Geosynthetic Clay Liners Used in Municipal Solid Waste Landfills,”

http://www.epa.gov/wastes/nonhaz/municipal/landfill/geosyn.pdf; “Geosynthetic Clay Liners in Waste 
59

Recommendations for Improving the Performance of Waste Containment Systems,”8 concluded

that if a compacted clay liner (CCL) or GCL is used alone, liquid migration can occur over the 

entire area of the liner that is subject to a hydraulic head. The report also concluded that in a 

composite liner, leakage will only occur at the location of the GM hole, but it will be much 

slower than flow through an orifice due to the hydraulic impedance provided by the CCL or 

GCL. The report cited above evaluated, among other qualities, the hydraulic efficiencies of a 

composite liner system comprised of a geomembrane (GM) liner over a GCL (GM/GCL) for 28 

cells at seven landfills. Liner hydraulic efficiencies were reported between 97% and 100%. 

However, the authors also reported potential stability problems with GCLs constructed on slopes 

greater than 10H:1V (5.7°), and that GCLs may not be appropriate for the disposal of liquid 

wastes or sludges. Taking all of this information into account, EPA believes that GM/GCL 

composite liners could offer a viable alternative to the geomembrane over compacted clay 

(GM/CCL) composite liner, but is not convinced that a GCL alone is a viable alternative to a 

composite liner. This is because the Agency is concerned that GCLs being much thinner than 

the two feet of compacted soil required for composite liners may allow for the flow of liquids 

through the GCL at a faster rate than through two feet of compacted soil. EPA, therefore, is 

addressing this concern by requiring that alternatives to the two feet of compacted soil have an 

equivalent or lower flow rate than two feet of compacted soil with a hydraulic conductivity no 

greater than 1x10-7cm/sec. The flow rate comparison must be made using Darcy’s equation for 

gravity flow through porous media described above. The hydraulic conductivity of the GCL 

must be determined using a recognized and generally accepted methodology, for example, 

ASTM Standard D6766 - 12, “Standard Test Method for Evaluation of Hydraulic Properties of 

Geosynthetic Clay Liners Permeated with Potentially Incompatible Aqueous Solutions,” ASTM 

International, West Conshohocken, PA, 2012, DOI: 10.1520/D6766-12, www.astm.org. Also, as 

 

Containment,” http://www.epa.gov/tio/tsp/download/2001_meet/prez/carson.pdf; and “Assessment and 

Recommendations for Improving the Performance of Waste Containment Systems,” 

http://www.epa.gov/nrmrl/pubs/600r02099/600r02099.htm

8

 “Assessment and Recommendations for Improving the Performance of Waste Containment Systems.” 

http://www.epa.gov/nrmrl/pubs/600r02099/600r02099.htm
60

noted previously, the design and construction of the alternative liner must be certified by a 

qualified professional engineer.

e. Use of a Lower Geosynthetic Clay Liner Below the Upper FML Component of a Composite 

Liner.

Comment: EPA expressed reluctance in allowing alternative liners for new CCR disposal 

facilities. This reluctance appears to be due, in part, to the expectation that owners or operators 

would propose a soil liner alone in place of the entire prescribed composite liner. We agree that 

a soil liner alone would not be as protective as the prescribed composite liner system, and should 

therefore not be considered an adequate substitute. We agree that an upper FML component is 

essential. However, there are other technically feasible alternatives to the lower two foot

compacted soil component that should be considered. Specifically, use of a geosynthetic clay 

liner (GCL) below the FML should be considered as an equivalent substitute for a compacted 

soil component. GCLs are factory-manufactured mats consisting of 0.75 lb/ft2of sodium 

bentonite clay between two geotextile layers, with a hydraulic conductivity of 5 x 10-9cm/sec per 

ASTM D5887. Due to their low hydraulic conductivity, GCLs are frequently used as a substitute 

for two-foot thick compacted soil liners in composite liner systems of many MSW landfills.

Based on the technical information presented above, CETCO requests that EPA’s final rule allow 

GCLs as an alternative to the low-permeability soil component underneath the FML for both the 

proposed RCRA Subtitle C and Subtitle D composite liner options. As outlined above, EPA 

research has shown that GCLs provide equivalent or superior performance compared with 

compacted clay liners. GCLs have become the state of the practice for waste containment 

facilities. If GCLs are not allowed, then utilities will be forced to construct compacted clay 

liners at all sites, which could be cost-prohibitive, especially if a suitable clay source is not 

available nearby. 

Comment Number: EPA-HQ-RCRA-2009-0640-06524-1 & EPA-HQ-RCRA-2009-0640-

06195-2

Organization: CETCO and University of Wisconsin Madison

Commenter Type: Other Company

Comment: Based on the technical information referenced herein and additional EPA and 

other publications, GMA recommends that the US EPA CCR Disposal Proposed Rule for either 

of the Subtitle C and/or Subtitle D Regulation options define and require a ‘composite liner’ 
61

consisting of two components: An upper component consisting of a minimum 60-mil flexible

membrane liner (FML), and a lower component consisting of a geosynthetic clay liner containing 

at least 0.75 lb/ft2 of sodium bentonite. If ‘composite liner’ is not redefined to include a lower 

component GCL, then at a minimum an alternative liner design should be provided

Comment Number: EPA-HQ-RCRA-2009-0640-02340-1

Organization: Geosynthetic Materials Association

Commenter Type: Trade Association

Comment: GMA recommends that the USEPA CCR Disposal Proposed Rule for either 

the proposed Subtitle C and Subtitle D Regulation option be revised to define a ‘composite liner’ 

as consisting of two components: An upper component consisting of a minimum 30-mil flexible

membrane liner (FML), and a lower component consisting of either at least a two-foot layer of 

compacted soil with a hydraulic conductivity of no more than 1 x 10-7 cm/s, or a geosynthetic 

clay liner (GCL) containing at least 0.75 lb/ft2 of sodium bentonite. If ‘composite liner’ is not 

redefined to include a lower component GCL, then the allowance of an alternative liner 

design/system should be included.

Comment Number: EPA-HQ-RCRA-2009-0640-04033-1

Organization: Geosynthetic Materials Association

Commenter Type: Trade Association

Comment: EPA's prescriptive one-design-fits-all approach is not suitable for all facilities, 

especially given the many local or regional variations in hydrology, geology, and other site 

characteristics.

Comment Number: EPA-HQ-RCRA-2009-0640-09358-12

Organization: Interstate Power and Light Company (IPL) and Wisconsin Power and Light 

Company (WPL)

Commenter Type: Electric Utility Company

Comment: Given the vastly different site-specific characteristics of units across the 

country, there is no "one-size-fits all" approach when it comes to regulatory design standards for 

CCR disposal units. CCR sites "vary widely in terms of topographical, geological, 

climatological, and hydrological characteristics," any regulatory regime must have the flexibility 

to tailor controls to the site-specific characteristics of the individual disposal units. There are 

alternate liner systems that can achieve the same level of protection as the composite liner 
62

system proposed by EPA. For example, geosynthetic clay liner ("GCL") or similar systems can 

meet or exceed the performance standards of clay liners and certainly are equivalent or superior 

in some circumstances to two feet of compacted soil in the lower component of the composite 

liner systems proposed under the Subtitle D option. Therefore, in many circumstances, a liner 

system using the GCl in lieu of the two feet of compacted soil readily enables a CCR disposal 

unit to meet the applicable groundwater monitoring standards.

Comment Number: EPA-HQ-RCRA-2009-0640-06198-8

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06203-13

Organization: Arizona Public Service Company (APS)

Commenter Type: Electric Utility Company

Response: EPA has reviewed the data provided with comments, as well as other technical 

reports and believes a composite liner comprised of a FML over a GCL is a viable alternative to 

a FML over a CCL, although we agree with the commenter that a GCL liner alone would not be 

as protective as the prescribed composite liner system. Therefore, the final rule allows

alternative liner designs for new CCR landfills, new CCR surface impoundments, lateral 

expansions of existing and new CCR landfills and when retrofitting existing CCR surface 

impoundments. These alternative designs must consist of two parts, an upper FML component 

and a lower component having a flow rate no greater than that of two feet of compacted soil 

having a hydraulic conductivity no greater than 1x10-7cm/sec. The flow rate comparison must 

be made using Darcy’s equation for gravity flow through porous media described above. The 

hydraulic conductivity for the two feet of compacted soil used in the comparison shall be no 

greater than 1 x 10-7cm/sec. The hydraulic conductivity of the GCL must be determined using a 

recognized and generally accepted methodology, for example, ASTM Standard D6766 - 12, 

“Standard Test Method for Evaluation of Hydraulic Properties of Geosynthetic Clay Liners 

Permeated with Potentially Incompatible Aqueous Solutions,” ASTM International, West 

Conshohocken, PA, 2012, DOI: 10.1520/D6766-12, www.astm.org. Also, as previously noted, 

the design and construction of the alternative liner must be certified by a qualified professional 

engineer.

f. Use of Clay Liners in Addition to Composite Liners.
63

Comment: The use of engineered clay liners on existing solid waste units offers adequate 

protection without the extreme and unnecessary expense of excavating material from existing 

units and installing composite liners. The legislative history of the Bevill Amendment along 

with statements from the D.C. circuit court indicate that Congress directed EPA to install a 

regulatory program for CCR's that utilizes cost-effective controls and avoids imposition of undue 

regulatory costs on the electric utility industry if at all possible (EDF vs EPA, 852 F.2d 1309, 

1315 (D.C. Cir. 1988). Considering these directions and the proven performance of engineered 

clay liners, EPA should not require the installation of composite liners at existing units under a 

RCRA subtitle D CCR regulatory program. The Louisiana solid waste regulatory program 

required engineered clay liners having a coefficient of permeability no greater than l x l0-7

cm/sec, up until the rule was modified in 1993, after which new surface impoundments were 

required to have either composite liners or alternative liners that provide equivalent groundwater 

protection. Groundwater monitoring over the course of years has shown that there has been no 

adverse impacts to groundwater from the commenter’s surface impoundments that used 

engineered clay liners.

Comment Number: EPA-HQ-RCRA-2009-0640-06868-7

Organization: Cleco Corporation

Commenter Type: Electric Utility Company

Comment: The long term performance of clay liners containing CCR wastes is not well 

understood at the present time. It is possible that some constituents in the wastes, such as salt, 

will desiccate a clay liner and produce cracks in the clays that would serve as a pathway for the 

migration of CCR wastes from the containment structure into the environment. In addition, a 

risk assessment would only typically give consideration to the current value or use of a resource, 

such as ground water with a high saline content, and not the potential future value and use of the 

resource that may be enhanced by technological treatment advances in the future.

Comment Number: EPA-HQ-RCRA-2009-0640-06313-104 & 105

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Information related to the field performance of compacted clay liners is readily available 

in the literature, including the aforementioned, “Assessment and Recommendations for 

Improving the Performance of Waste Containment Systems”, R. Bonaparte, D.E. Daniel, and 
64

R.M. Koerner, EPA/600/R-02/099, EPA National Risk Management Research Laboratory, 

Cincinnati, OH, http://www.epa.gov/nrmrl/pubs/600r02099/600R02099. In chapter 4 of this 

document, researchers evaluated a database of 89 compacted clay liners and test pads. The study 

found that although all 89 liners in the database were designed and constructed to meet a field 

hydraulic conductivity of 1 x 10-7cm/sec, this value was not met at more than one-fourth (26 

percent) of the sites in the database. In other words, one-fourth of the compacted clay liners in 

the database could experience greater leakage in the field than initially modeled.

Comment Number: EPA-HQ-RCRA-2009-0640-06195-2

Organization: CETCO

Commenter Type: Other Company

Response: Upon further consideration, EPA is finalizing today’s rule to allow owners or 

operators of existing CCR landfills and surface impoundment with a clay liner to continue to 

operate these disposal units for the reminder of their useful life. Based on the results of EPA’s 

risk assessments, the Agency has determined that CCR disposal units that have a clay liner and 

that meet the technical requirements in the rule, i.e., the groundwater monitoring and corrective 

action requirements, and the closure and post closure care requirements, will be protective of 

human health and the environment. However, as explained in section VI.F.3.a above, unlined 

surface impoundments that are leaking are required to close in accordance with the closure 

requirements in §257.102 of today’s rule.

g. Alternative Liners Only in States with Permitted Programs.

Comment: Alternative designs should only be allowed in states with regulations for 

permit application review, public notice and an opportunity for hearings. EPA could craft a 

regulation requiring that these alternatives only be allowed in states with RCRA subtitle D 

permitting programs equivalent to that required for delegation of authority for MSW landfills, 

found at 40 CFR 239. There would be no need for the actual EPA delegation of authority, but 

the rule would give a framework to use for such requests.

Comment Number: EPA-HQ-RCRA-2009-0640-06260-80

Organization: Kentucky Department for Environmental Protection

Commenter Type: State Government

Response: The Agency disagrees. To support a standard under section 1008(a) or 

4004(a) EPA is required to prove that the rules will be protective based on the record available at 
65

the time the rule is promulgated. In the absence of a record demonstrating the adequacy of state 

programs, EPA cannot simply rely on subsequent state action to demonstrate that a particular 

requirement will meet the 4004(a) standard. As discussed in Section IV of the preamble to the 

final rule, the mere existence of the provisions mentioned by the commenter does not prove the 

adequacy of the state program, but also by how the state implements the requirements (e.g., 

when and how are variances or exemptions granted). And as discussed in that section, EPA 

lacks sufficient information to make any determination on many state programs. By contrast, we 

have determined, based on the available information, that alternative composite liner designs can 

be as protective as the composite liner design in the proposed rule, provided a qualified 

professional engineer certifies that the alternative to the two feet of compacted soil has a flow 

rate no greater than that of two feet of compacted soil having a hydraulic conductivity no greater 

than 1 x 10-7centimeters per second. (See the previous Response to Comments for further 

discussion.)

h. Performance-based Standards. 

Comment: Any design standard should be made performance-based rather than 

prescriptive to provide for flexibility in design and construction. Performance-based standards 

should be allowed to supplement default, prescribed engineering standards and there are infinite 

site variables that can allow for flexibility in design and not require specific liner types but still 

meet the goal addressing hydraulic conductivity to protect human health and the environment. 

Comment Number: EPA-HQ-RCRA-2009-0640-08850-13

Organization: Lansing Board of Water & Light (BWL)

Commenter Type: Electric Utility Company

Comment: By establishing performance standards to be met, a framework allowing for 

innovation, incorporation of developing “best practices” and site--- specific solutions is 

promoted. This approach can result in solutions that are not only more cost---effective, but can 

also provide better protection of property and the environment, in view of the specific site 

conditions encountered. 

Comment Number: EPA-HQ-RCRA-2009-0640-06831-2

Organization: MACTEC Engineering and Consulting, Inc.

Commenter Type: Other Company
66

Comment: Change the definition of “composite liner” from “....and the lower must 

consist of at least two-foot layer (sic) of compacted soil with a hydraulic conductivity of no more 

than 1x10-7cm/sec” to read as follows: “... and the lower component must consist of or be 

equivalent or superior to a two-foot layer of compacted soil with a hydraulic conductivity of no 

more than 1x10-7cm/sec.”

Comment Number: EPA-HQ-RCRA-2009-0640-06529-40

Organization: NiSource Corporate Services

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06532-34

Organization: Southern Illinois Power Cooperative

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09239-68

Organization: Prairie State Generating Company, LLC (PSGC)

Commenter Type: Electric Utility Company

Comment: Providing an alternative standard to address circumstances where the 

requirement is highly dependent on site-specific conditions is appropriate when mechanisms are 

in place to ensure that the alternative is protective of health and the environment. Certification 

by a registered professional provides an appropriate level of certainty that the performance 

standard is being met. In addition, notification would be provided to the state and the public 

such that enforcement could be pursued if necessary. Using sound science and engineering 

principles to develop a disposal design is a more prudent approach rather than an across the 

board regulatory mandate regardless of the environmental parameters that need to be considered 

when designing a disposal site. 

Comment Number: EPA-HQ-RCRA-2009-0640-06529-40

Organization: NiSource Corporate Services

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06532-34

Organization: Southern Illinois Power Cooperative

Commenter Type: Electric Utility Company
67

Comment Number: EPA-HQ-RCRA-2009-0640-09239-68

Organization: Prairie State Generating Company, LLC (PSGC)

Commenter Type: Electric Utility Company

Comment: Establishing performance standards would give flexibility to tailor a system to 

meet the site-specific characteristics of an individual disposal unit. These would include 

topographical, geological, climatological, and hydrological characteristics. EPA should not limit 

alternative liner design systems and deny owners/operators the ability to utilize systems that are

equally or more protective as the composite liner system proposed in the Subtitle D options. 

Additionally, due to the significant volume of clay that is needed to line a facility, as well as the 

likelihood that other units would need the same materials in the same timeframe, there may be an 

insufficient supply of clay and/or it may be difficult to transport the needed volume of clay to the 

site.

Comment Number: EPA-HQ-RCRA-2009-0640-06833-20

Organization: Dominion Resources Services, Inc.

Commenter Type: Electric Utility Company

Comment: Given that CCR sites “vary widely in terms of topographical, geological, 

climatological, and hydrological characteristics,” any regulatory regime must have the flexibility 

to tailor controls to the site-specific characteristics of the individual disposal units. Otherwise, 

the same concerns with over-regulation that EPA correctly described with respect to a Subtitle C 

program will arise under a Subtitle D nonhazardous waste program for CCRs. For example, it is 

not necessary to require the installation of a composite liner system to a lateral extension of an 

existing CCR landfill in the arid Southwest where the distance to groundwater may be several 

hundred feet or more. There are alternate liner systems that can achieve the same level of 

protection as the composite liner system proposed by EPA.

Comment Number: EPA-HQ-RCRA-2009-0640-06198-8

Organization: Ameren Corporation

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-06203-13

Organization: Arizona Public Service Company (APS)

Commenter Type: Electric Utility Company
68

Comment Number: EPA-HQ-RCRA-2009-0640-06956-13

Organization: Tri-State Generation & Transmission

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-09536-9

Organization: Tennessee Valley Authority

Commenter Type: Electric Utility Company

Comment Number: EPA-HQ-RCRA-2009-0640-10483-53

Organization: Utility Solid Waste Activities Group (USWAG) et al.

Commenter Type: Trade Association

Comment: As landfill designers, we have successfully designed, permttted, and 

constructed numerous Subtitle D Landfill Sites utilizing geosynthetic clay liners with site soils, 

and believe that the proposed coal ash landfill regulations should include language to incorporate 

equivalent or superior liner designs.

Comment Number: EPA-HQ-RCRA-2009-0640-05825-1

Organization: TriAD Environmental Consultants, Inc.

Commenter Type: Other Company

Comment: Alternative liner designs based upon specific performance standards 

referenced in 40 CFR Part 258.40 should also be recognized.

Comment Number: EPA-HQ-RCRA-2009-0640-06723-21

Organization: West Virginia Department of Environmental Protection (WVDEP)

Commenter Type: State Government

Comment: The Subtitle D option must provide flexibility in the design of new disposal 

units and provide performance standards to be met.

Comment Number: EPA-HQ-RCRA-2009-0640-09284-52

Organization: Virginia Department of Environmental Quality

Commenter Type: State Government

Comment: The final rule should include the flexibility to use alternatives to composite 

liners that are demonstrated to achieve the same long-term performance standards.

Comment Number: EPA-HQ-RCRA-2009-0640-07048-12

Organization: TransAlta Centralia Generation

Commenter Type: Electric Utility Company
69

Comment: No performance standards should be permissible since state agencies might 

adopt weak performance standards that would not be adequate to protect human health and the 

environment. Major state regulatory failures, such as those identified by EPA and others, 

indicate that this is a likely scenario (USEPA, 2007; Environmental Integrity Project and 

Earthjustice, 2010; Environmental Integrity Project, Earthjustice, and Sierra Club, 2010). 

Comment Number: EPA-HQ-RCRA-2009-0640-06313-104

Organization: Earthjustice et. al.

Commenter Type: Advocacy Group

Response: For the reasons discussed previously, the final rule incorporates a performance 

standard for the composite liner requirement allowing alternative liner designs for new CCR 

landfills, new CCR surface impoundments, retrofits of existing surface impoundments, and any 

lateral expansion provided the owner or operator provides certification by a qualified 

professional engineer that the lower component of the alternative composite liner has an 

equivalent or lower flow rate as two feet of compacted soil with a hydraulic conductivity no 

greater than 1 x 10-7centimeters per second.