United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5305W)
EPA530-R-99-001
May 1999
www.epa.gov/osw
&EPA
Guide for Industrial Waste
Management
^nla?4-'
Building^
Partnerships
Protecting
Ground Water
Surface Water
Air
f£r
GA>Printed on paper that contains at least 30 percent post
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Guide
for
Industrial Waste Management
U.S. Environmental Protection Agency
Office of Solid Waste
401 M Street SW (5305W)
Washington, DC 20460
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Disclaimer
Disclaimer
All aspects of this guidance are in draft form, subject to comment, and not intended to be
used in current waste management decision-making. The draft guidance and modeling tools
have been developed only to address issues within the scope of the guidance. The guidance is
not a guideline or regulation under the Resource Conservation and Recovery Act, nor can this
draft guidance be relied upon to create any rights ^enforceable by any party in litigation with
the United States. EPA retains the right to modify the final guidance from time to time.
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Acknowledgements
Acknowledgements
The following members of the Industrial Waste Focus Group and the Industrial Waste
Steering Committee are gratefully acknowledged for all of their time and assistance in the
development of this draft guidance document.
Current Industrial Waste Focus Group Members
Paul Bork, The Dow Chemical Company
Walter Carey, Nestle, USA, Inc. and New Milford Farms
Rama Chaturvedi, Bethlehem Steel Corporation
H.C. Clark, Rice University
Barbara Dodds, League of Women Voters
Chuck Feerick, Exxon Company USA
Robert Giraud, DuPont Company
Jonathan Greenberg, Browning-Ferris Industries
John Harney, Citizens Round Table/PURE
Richard Jar man, National Food Processors Association
James Meiers, Indianapolis Power and Light Company
Andrew Miles, The Dexter Corporation
Scott Murto, General Motors and American Foundry Society
James Roewer, Edison Electric Institute
Edward Repa, Environmental Industry Association
Tim Saylor, International Paper
Amy Schaffer, American Forest & Paper Association
Ed Skernolis, WMX Technologies, Inc.
Michael Wach, Western Environmental Law Center
David Wells, University of South Alabama Medical Center
Observer:
Pat Gwin, Cherokee Nation of Oklahoma
Past Industrial Waste Focus Group Members
Doris Cellarius, Sierra Club
Brian Forrestal, Laidlaw Waste Systems
Michael Gregory, Arizona Toxics Information and Sierra Club
Gary Robbins, Exxon Company
Kevin Sail, National Paint & Coatings Association
Bruce Steiner, American Iron & Steel
Lisa Williams, Aluminum Association
in
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Acknowledgements
Acknowledgements (cont.)
Current Industrial Waste Steering Committee Members
Kerry Callahan, Association of State and Territorial Solid Waste Management Officials
Marc Crooks, Washington State Department of Ecology
Cyndi Darling, Maine Department of Environmental Protection
Jon Dilliard, Montana Department of Environmental Quality
Anne Dobbs, Texas Natural Resources Conservation Commission
Richard Hammond, New York State Department of Environmental Conservation
Elizabeth Haven, California State Waste Resources Control Board
Jim Hull, Missouri Department of Natural Resources
Jim Knudson, Washington State Department of Ecology
Chris McGuire, Florida Department of Environmental Protection
Gene Mitchell, Wisconsin Department of Natural Resources
William Pounds, Pennsylvania Department of Environmental Protection
Bijan Sharafkhani, Louisiana Department of Environmental Quality
James Warner, Minnesota Pollution Control Agency
Robert Dellinger, Office of Solid Waste, U.S. EPA
Richard Kinch, Office of Solid Waste, U.S. EPA
Paul Cassidy, Office of Solid Waste, U.S. EPA
John Sager, Office of Solid Waste, U.S. EPA
Pat Cohn, Office of Solid Waste, U.S. EPA
Dwight Hlustick, Office of Solid Waste, U.S. EPA
Ginny Cohen-Bradley, Office of Solid Waste, U.S. ;EPA
Charlotte Bertrand, Office of Solid Waste, U.S. EPA
Mark Schuknecht, Office of Solid Waste, U.S. EPA
Past Industrial Waste Steering Committee Members
Pamela Clark, Maine Department of Environmental Protection
Norm Gumenik, Arizona Department of Environmental Quality
Steve Jenkins, Alabama Department of Environmental Management
Jim North, Arizona Department of Environmental Quality
This guidance document, CD-ROM, and the ground-water and air modeling tools were
developed with assistance from Eastern Research Group (Birute Vanatta and Marty Marchaterre,
Project Officers), Science Applications International Corporation (Chris Long and Bob Stewart,
Project Officers), HydroGeologic, Inc. (Sam Figuli, Project Officer), and Research Triangle
Institute (Anne Cook Lutes , Project Officer and Terrence K. Pierson, Program Director).
IV.
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Contents
Introduction
Parti. Getting Started
Chapter 1. Building Partnerships
Chapter 2. Characterizing Waste
Chapter 3. Integrating Pollution
Chapter 4. Considering the Site
Part II. Protecting Air Quality
Chapter 5. Protecting Air
Part III. Protecting Surface Water
Chapter 6. Protecting Surface Water
Part IV. Protecting Ground Water
Chapter 7A. Assessing Risk
Chapter 7B. Designing and Installing Liners: Technical Considerations for Surface
Impoundments, Landfills, and Waste Piles
Chapter 7C.Designing a Land Application Program
Part V. Ensuring Long-Term Protection
Chapter 8. Operating the Waste Management System
Chapter 9. Monitoring Performance
Chapter 10. Taking Corrective Action
Chapter 11. Performing Closure and Post-Closure Care
Glossary
V.
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Introduction
EPA's Guide for Industrial Waste Management
Introduction
This voluntary guide is designed to assist facility managers, state
and tribal environmental managers, and the public to evaluate
and choose protective practices for managing industrial waste in
new landfills, waste piles, surface impoundments, and land appli-
cation units. This guide identifies the components of a sound
waste management system and why each is important. It also
includes ground-water and air models, as well as other tools to
help tailor waste management practices to a particular facility.
This guidance reflects four underlying principles:
• Protect human health and the environment. This is the focal point. The guidance is
multi-media, emphasizing surface water, ground water, and air protection, with a
comprehensive framework of technologies and practices that make up a sound waste
management system.
• Tailor management practices to risks. There is enormous diversity in the nature of
industrial wastes and the environmental settings where they are managed. The guid-
ance provides conservative national management recommendations and user-friendly
modeling tools to make location-specific adjustments It also identifies complex ana-
lytic tools to conduct comprehensive site-specific analyses.
• Affirm state and tribal leadership. States, tribes, and some local governments have
primary responsibility for adopting and implementing programs to ensure proper
management of industrial waste. It is important to note that individual states or
tribes may have more stringent or extensive regulatory requirements based on local
or regional conditions or policy considerations. This guide complements, but does
not supersede those regulatory programs. It can help you make decisions on meeting
requirements and filling potential gaps. Facility managers and the public, consult
with appropriate regulatory agencies throughout the process to understand their"
requirements and how they want you to use this guide.
• Foster a partnership. The public, facility managers and regulatory agencies share a
common interest in preserving quality neighborhoods, protecting the environment
and public health, and enhancing the economic well-being of the community. This
guide provides a common technical framework to facilitate discussion. Stay involved
and work together to achieve meaningful environmental results.
VII.
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Introduction
I. Setting the context
About 7.6 billion tons of industrial solid waste are generated and managed on-site at indus-
trial facilities each year. Almost 97 percent is wastewater managed in surface impoundments;
the remainder is managed in landfills, waste piles, and land application units. Most of these
wastewaters are treated and ultimately discharged into surface waters under Clean Water Act
permits issued by EPA or state governments (National Pollutant Discharge Elimination System
or NPDES permits). These wastes come from; the broad spectrum of American industries. This
guidance is not designed to address municipal wastes or wastes defined as hazardous under
federal or state laws.
EPA and 12 state representatives selected from the membership of the Association of State and
Territorial Solid Waste Management Officials (ASTSWMO) began development of this guidance in
1996 with the formation of a State/EPA Steering Committee. We set out with three goals: first to
define a baseline of management practices that protect human health and the environment; sec-
ond, to complement existing state and tribal regulatory programs; and third to produce an effec-
tive and user-friendly guide that all stakeholders will rely on. The Steering Committee is co-
chaired by one EPA and one state member. At;the same time, we had the benefit of a Focus
Group of industry and public interest stakeholders chartered under the Federal Advisory
Committee Act to consult with us throughout:development of the guidance. The Steering
Committee and Stakeholders' Focus Group members are listed in the front of this document.
The draft guide you have in hand reflects a remarkably productive consultative process.
Focus Group members provided extensive comment and commitment of their time through-
out. Their thoughtful input helped us to make this a more comprehensive and effective prod-
uct, although the final decisions are those of the Steering Committee. Right now, our work is
half completed. The Steering Committee will reconvene to consider the feedback we receive
during the comment period and continue to seek advice from the Stakeholders' Focus Group
as we develop the final guidance.
II. Scope
This guidance is useful for a broad array of industrial process wastes, especially those that
are managed at the industrial facilities where they are generated. However, we did. not consider
certain extractive wastes, such as from minirig or oil and gas production, and recommendations
may not be suitable for these wastes without further tailoring. Furthermore, any facilities that
receive municipal solid waste are subject to municipal landfill criteria at 40 CFR Part 258 and
to separate state or tribal municipal landfill regulations and are not addressed by this guidance.
The guidance focuses on the design of new units. Liner design and siting concerns are clear-
ly directed at new units. However, other management recommendations, such as for ground-
water monitoring, corrective action, operating practices, and closure and post closure care, may
be helpful in making management decisions for currently operating units as well.
VIII.
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Introduction
III. Using the guidance
There are a few key steps to follow:
• Understand and comply with all existing Federal, state or tribal regulations, permits
and operating agreements that apply to a waste management unit. The guidance is
designed to complement them, never to take their place.
• Thoroughly characterize constituents and concentrations in the waste. Waste characteri-
zation is the foundation for choosing and implementing tailored, protective management
practices. To assess potential ground-water risks, the guidance provides drinking water
maximum contaminant levels (MCLs), when they exist, and health-based reference levels
for 191 constituents. To assess potential air risks, the guidance provides inhalation
health-based reference levels for 95 volatile and semi-volatile constituents.
• Take advantage of pollution prevention opportunities. Pollution prevention, recycling
and, to some extent, treatment, can minimize reliance on waste disposal, reduce disposal
costs and reduce future costs and liabilities for closure and post closure care and potential
corrective action. Pollution prevention can also conserve raw materials.
• Build a partnership between all stakeholders who have an interest in waste manage-
ment decisions. Keep stakeholders informed and involved on an ongoing basis.
• Tailor management practices to the wastes and the environmental setting of the unit.
The guide covers all the components of a sound waste management system. It recom-
mends best management practices and the key factors to take into account in siting,
operation, design, monitoring, corrective action, closure and post closure care. The
guidance also directs you to a wide variety of useful tools and resources, and includes a
number of these tools as appendices. In particular, the guidance recommends risk-
based approaches to choose liner systems and waste application rates for ground-water
protection and to evaluate the need for air controls.
Here is an example of how the risk-based evaluation would work for choosing a liner system
design. For ground-water protection, the approach is three-tiered, relying on modeling fate and
transport of constituents through subsurface soils to ground water. Successive tiers in the analy-
sis incorporate more site-specific data to tailor protective management practices to your particu-
lar circumstances.
Tier 1 - National Evaluation: Once you know the concentrations of constituents in the waste,
generic "look-up tables" give you recommendations on appropriate liner design. If the waste
going into a unit contains several constituents, choose the most protective liner design indi-
cated for any of the constituents.
Tier 2 - Location Adjusted Evaluation: You can use location-specific data for up to seven of the
most sensitive waste and site-specific variables to assess whether a particular liner design will
be protective. The CD ROM version of the guidance provides a ground-water model for Tier
1 and 2 analyses.
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Introduction
Tier 3 - Comprehensive Site Assessment: This tier relies on a comprehensive analysis of specific
waste and site characteristics to assess whether a particular liner design will be protective.
The guidance identifies a number of models for this detailed analysis.
IV. Next Steps
We have provided the draft guidance in a printed version, on a CD ROM and it is accessible
through the Internet at . Now, EPA and the state participants from
ASTSWMO welcome your comments on all aspects of this draft: the substantive recommenda-
tions, the risk-based modeling tools, practicality and user friendliness. The accompanying
Federal Register notice and some chapters of the guidance frame a number of key questions and
issues to help you get started. The public comment period will extend for six months from the
date of the Federal Register notice. Based on your comments, we will make revisions and release
the final guidance.
EPA and state representatives participating in this effort believe that the recommendations in
the final version of this guide can help to improve management of industrial waste at facilities
across the country. EPA and ASTSWMO will widely disseminate the final version of the guide
and explain the rationale behind the recommendations to regulators, industries and the public
to foster understanding and encourage stakeholders to integrate final recommendations in
future industrial planning throughout the country.
V. Final Thoughts
This guidance is designed for users with different levels of knowledge and experience.
Because many of the recommendations here address complex and highly technical practices
and engineered systems, users are urged to seek out technical experts and resources to assist in
detailed planning, design and implementation.
Facility managers, regulatory agency staff, and the public all have a different role in ensuring
protective waste management and, therefore, this guidance can help all of you.
• Facility managers: The guide can help you make the decisions necessary to ensure
environmentally responsible unit siting, design, and operation in partnership with state
and tribal regulators and the public.
• State and tribal regulators: The guide provides a handy implementation reference that
complementsiyour program and can help you address any gaps.
• The public: The guide can help you be an informed and knowledgeable partner in
addressing industrial waste management issues in your community.
x.
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Part I
Getting Started
Chapter 1
Building Partnerships
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Contents
I. Benefits of Building Partnerships 1-1
II. Principles of Building Partnerships 1-1
A. Develop a Partnership Involvement Plan 1-2
B. Inform the State and Public About New Facilities or Significant Changes in
Facility Operating Plans 1-2
C. Make Knowledgeable and Responsible People Available for Sharing Information 1-5
D. Provide Information About Facility Operations 1-6
III. Understanding Risk Assessment 1-7
A. Introduction to Risk Assessment 1-7
B. Types of Risk 1-7
C. Assessing Risk 1-9
1. Hazard Identification 1-10
2. Exposure Assessment: Pathways, Routes, and Estimation 1-10
3. Risk Characterization 1-14
D. Results : 1-15
IV. Information on Environmental Releases 1-15
Building Partnerships Action Items 1-16
Resources 1-17
Tables
Tablel: Effective Methods for Public Notification 1-3
Figures:
Figure 1: Multiple Exposure Pathways/Routes 1-11
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Getting Started—Building Partnerships
Building Partnerships
Build a partnership through an active involvement program
designed to build trust and credibility between a company that
generates and manages waste, the community within which the
company lives and works, and the state agency that regulates
the industry.
R:sidents located near waste man-
agement units want to understand
the management activities taking
place in their neighborhoods.
They want to know that waste is
being managed safely, without danger to pub-
lic health or the environment. Create opportu-
nities for dialogue between industries, states,
and concerned citizens before decisions are
made. Partnership efforts also need to be
ongoing in order to be successful.
I. Benefits of
Building
Partnerships
Building partnerships in the decision-mak-
ing process provides a number of benefits:
• Enhanced understanding of waste man-
agement activities at an industrial facility;
• Enhanced understanding of industry,
state, and community concerns;
• Greater support of industry and state
policies;
• Reduced delays and costs associated with
opposition and litigation; and
• A positive image and relationship.
II. Principles of
Building
Partnerships
Regardless of the size or type of an indus-
try waste unit, industries, states, and local
communities can all follow similar principles
of building partnerships. These principles are
based on various state public involvement
guidance documents, various EPA publica-
tions, and state requirements for waste facili-
ties. These principles embody sound business
practices and common sense, and may go
beyond state requirements that call for public
participation during the issuance of a permit.
This guidance document recommends princi-
ples that can be adopted throughout the oper-
ating life of facilities, not just during the per-
mitting process. Following these principles
This chapter will help address the
following questions:
• What are the benefits of building
partnerships?
• What building partnership methods
have been successful? ,
• What is involved in preparing a
meeting?
1-1
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Getting Started—Building Partnerships
will help all involved consider the full range
of activities possible to give partners an active
voice in the decision-making process, and in
so doing, will result in a positive working
relationship.
A. Develop a Partnership
Involvement Plan
The key to effective involvement, like any
activity, is good planning. Developing a plan
for how and when to involve all parties in the
decision-making process will help to make
involvement activities run smoothly and
achieve the best results. Developing an
involvement plan also helps identify concerns
and determine which involvement activities
best address those concerns. .
The first step in developing an involve-
ment plan is to work with the state agency to
understand what involvement requirements
exist. (State contacts are provided in
Appendix I.) Existing state requirements deal-
ing with involvement plans must be followed.
After this step, it
will be important
to assess how
much interest
facility activities
will generate in
the community.
Several criteria
influence the
amount of public •
interest, including
implications for
public health and
welfare, current relationships between the
facility and community members, and the
community's political and economic climate.
Even if facilities have not generated much
public interest in the past, involving the pub-
lic is a good idea. Interest in a facility can
increase suddenly when changes to existing
activities are proposed or when residents' atti-
tudes and a community's political or econom-
ic climate change over time.
To gauge public interest in a facility and to
identify the community's major concerns,
industries can conduct interviews with com-
munity members. They can first talk with
representatives from major community
groups, such as civic groups, religious organi-
zations, and business associations. If interest
in the facility seems high, industries can con-
sider conducting a more comprehensive set of
community interviews. Other individuals to
interview may include the facility's immediate
neighbors, representatives from other agen-
cies and environmental organizations, and
any individuals in the community who have
expressed interest in the facility.
Using the information gathered during the
interviews, industries can develop a list of the
major community concerns regarding the
facility. They can then begin to engage in
involvement activities necessary to address
those concerns. These activities form the
basis of a partnership involvement plan.
B. Inform the State and
Public About New
Facilities or Significant
Changes in Facility
Operating Plans
A facility's decision to change its opera-
tions provides a valuable opportunity for
involvement. Notifying the state and public of
new facilities and proposed changes gives
them the opportunity to identify applicable
state requirements and comment on matters
that apply to them.
1-2
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Getting Started—Building Partnerships
What are examples of effective
methods for notifying the public?
Table 1 presents examples of effective meth-
ods for public notification and associated
advantages and disadvantages. The method
used at a particular site, and within a particu-
lar community, will depend on the type of
information or issues that need to be commu-
nicated and addressed. Public notices usually
provide the name and address of the facility
owner and operator and a brief description of
the change being considered. After a public
notice is issued, industries can develop infor-
mative fact sheets to explain proposed changes
in more detail. Fact sheets and public notices
can include the name and telephone number
of a contact person who is available within the
industry to answer questions.
Table 1
Effective Methods for Public Notification
Methods Features Advantages Disadvantages I
i 1
Briefings
Mailing of key technical
reports or environmental
documents
News conferences
Newsletters
Newspaper inserts
Paid advertisements
News releases
Personal visit or phone call
to key officials or group lead-
ers to announce a decision,
provide background information,
or answer questions.
Mailing technical studies or
environmental reports to other
agencies, leaders of organized
groups, or other interested parties.
Brief presentation to reporters,
followed by a question-and-
answer period, often accompa-
nied by handouts of presenter's
comments.
Brief description of what is going
on, usually issued at key intervals
for all people who have shown
interest.
Much like a newsletter, but dis-
tributed as an insert in a news-
paper.
Advertising space purchased in
newspapers or on the radio or
television.
A short announcement or news
story issued to the media to get
interest in media coverage of the
story.
Provides background information.
Determines reactions before an issue
"goes public." Alerts key people to
issues that may affect them.
Provides full and detailed information
to people who are most interested.
Often increases the credibility of stu-
dies because they are fully visible.
Stimulates media interest in a story.
Direct quotes often appear in
television and radio. Might draw
attention to an announcement or
generate interest in public meetings.
Provides more information than can
be presented dirough the media to
those who are most interested. Often
used to provide information prior to
public meetings or key decision points.
Helps to maintain visibility during ex-
tended technical studies.
Reaches the entire community with
important information. Is one of the
few mechanisms for reaching everyone
in the community dirough which you
can tell the story your way.
Effective for announcing meetings or
key decisions or as background materi-
al for future media stories.
Might stimulate interest from the media.
Useful for announcing meetings-or
omajor decisions or as background
material for future media stories.
Requires time.
Costs money to print and
mail. Some people might not
read the reports.
Reporters will only come if
the announcement or presen-
tation is newsworthy. Cannot
control how the story is pre-
sented, although some direct
quotes are likely.
Requires staff time. Costs
money to prepare, print and
mail. Stories must be
objective and credible, or
people will react to the news-
letters as if they were propa-
ganda.
Requires staff time to prepare
the insert, and distribution
costs money. Must be prepared
to newspaper's layout
specification.
Advertising space can be cost-
ly. Radio and television may
entail expensive production
costs to prepare the ad.
Might be ignored or not read.
Cannot control how the infor-
mation is used.
1-3
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Getting Started—Building Partnerships
Table 1
Effective Methods for Public Notification (cont.)
Methods
Presentations to civic
and technical groups
Press kits
Advisory groups and
task forces
Focus groups
Telephone line
Meetings
Features
Deliver presentations, enhanced
with slides or overheads, to key
community groups.
A packet of information distribu-
ted to reporters.
A group of representatives of key
interested parties is established.
May be a policy, technical, or citi-
zen advisory group._
Small discussion groups
established to give "typical" reac-
tions of the public. Conducted
by a professional facilitator.
Several sessions may be conducted
with different groups.
Widely advertised phone number
that handles questions or provides
centralized source of information.
Less formal meetings for people to
present positions, ask questions,
and so forth.
Advantages Disadvantages
Stimulates communication with key
community groups. Can also provide
in-depth responses.
Stimulates media interest in the story.
Provides background information that
reporters can use for future stories.
Promotes communication between
key constituents. Anticipates public
reaction to publications or decisions.
Provides a forum for reaching
consensus.
Provides in-depth reaction to ideas or
decisions. Good for predicting emo-
tional reactions.
Gives people a sense that they know
whom to call. Provides a one-step
service of information. Can handle
two-way communication.
Highly legitimate form for the public
to be heard on issues. Can be struc
tured to permit small group interac-
tion — anyone can speak.
Few disadvantages except
some groups can be hostile.
Few disadvantages except
cannot control how the infor-
is used and might not be
read.
Potential for controversy exists
if "advisory" recommendations
are not followed. Requires
substantial commitment of
staff time to provide support
to committees.
Gets reactions, but no know-
ledge of how many people
share those reactions. Might
be perceived as an effort to
manipulate the public.
Is only as effective as the per-
son answering the telephone.
Can be expensive.
Unless a small group discuss-
ion format is used, it permits
only limited dialogue. Can
get exaggerated positions or
grandstanding. Requires
staff time to prepare for
meetings.
U.S. EPA 1990. Sites for Our Solid Waste: A Guidebook for Effective Public Involvement.
What is involved in preparing a
meeting with industry, communi-
ty, and state representatives?
Meetings can be an effective means of giving
and receiving comments and addressing con-
cerns. To publicize a meeting, the date, time, and
location of the meeting should be placed in a
local newspaper and/or advertised on the radio.
To help ensure a successful dialogue, meetings
should be at times convenient for members of
the community, such as early in the evenings
during the week, or ori weekends. An interpreter
may need to be obtained (hire or seek a volun-
teer) if the local community includes residents
whose primary language is not English.
Prior to a meeting, an industry should devel-
op a waste management plan for the facility or
come to the meet-
ing prepared to
describe how the
industrial waste
from the facility will
be managed. A
waste management
plan provides a
starting point for
public comment
and input. Keep
data presentations
simple and provide
information relevant
1-4
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Getting Started—Building Partnerships
to the audience. Public speakers should be
able to respond to general questions, as well as
technical questions. Also, industry should
review and be familiar with the concerns of
groups or citizens who have previously
expressed an interest in the facility. In addi-
tion, it is important to anticipate questions and
plan how best to respond to these questions at
a meeting.
State representatives should also be pre-
pared to answer questions that are anticipated
at the meeting. State representatives should
be prepared to answer questions on specific
regulatory or compliance issues, as well as to
address how the industry has been working
in cooperation with the state agency.
Questions often asked at a meeting
include:
• What are the risks to me associated with
the operations?
• Who should I contact at the facility if I
have a question or concern?
• How will having the facility nearby bene-
fit the area?
• Will there be any noticeable day-to-day
effects on the community?
• Which processes generate industrial
waste, and what types of waste are
generated?
• How will the waste streams be treated or
managed?
• What are the construction plans for any
proposed containment facilities?
• What are the intended methods for moni-
toring and detecting emissions or poten-
tial releases?
• What are the plans to address accidental
releases of chemicals or wastes at the site?
• What are the plans for financial assur-
ance, closure, and post-closure care?
• What are the applicable state regulations?
• How long will it take to issue the permit?
• How will the permit be issued?
• Who should I contact at the state agency
if I have questions or concerns about the
facility?
At the meeting, industry should invite
public and state comments on the proposed
change, and tell community members where,
and to whom they should send written com-
ments. Industry can choose to respond to
comments in several ways. For example, tele-
phone calls, additional fact sheets, or addi-
tional meetings can all be used to address
comments. Responding promptly to residents'
comments and concerns demonstrates an
honest attempt to address them.
C. Make Knowledgeable
and Responsible People
Available for Sharing
Information
Having an industry contact(s) available to
answer the public's questions and provide
information helps assure citizens that the
industry is actively listening to their con-
cerns. Having a state contact available to
address the public's concerns about the facili-
ty can also make sure that concerns are being
heard and addressed.
In addition to identifying a contact person,
industry and states should consider setting
up a telephone line, staffed by employees, for
citizens to call and obtain information
promptly about the facility. Opportunities for
face-to-face interaction between community
members and facility representatives include
onsite information offices, open houses, ,
workshops, or briefings. Information offices
function similarly to information repositories,
except that an employee is present to answer
1-5
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Getting Started—Building Partnerships
questions. Open
houses are infor-
mal meetings on-
site where resi- '
dents can talk to
company officials
one-to-one.
Similarly, work-
shops and brief-
ings enable com-
munity mem-
bers, state offi-
cials, and indus-
try representa-
tives to interact, ask questions, and learn
about the activities at the facility. Web sites
may also serve as a useful tool for industry,
state, and community representatives to share
information and ask questions.
D. Provide Information
About Facility
Operations
Providing information about site opera-
tions is an invaluable way to help the public,
understand waste management activities at a
site. Facility tours, maintaining a publicly
accessible information repository at the site,
developing exhibits to explain operations,
and distributing information through the
publications of established organizations are
examples that can serve to inform a commu-
nity. Appendix II describes some of the public
involvement activities that are being conduct-
ed by various companies around the country.
Conduct facility tours. Scheduled facility
tours allow the community and state to visit
the facility and ask questions about how it
operates. By seeing a facility first-hand, resi-;
dents learn how waste is managed and can
become more confident that it is being man-
aged safely. Individual citizens, local officials,
interest groups, students, and the media
might want to take advantage of facility tours.
In planning tours, determine the maximum
number of people that can be taken through
the facility safely, and think of ways to
involve tour participants in what they are see-
ing, such as providing hands-on demonstra-
tions. It is also a good idea to have company
individuals available to answer technical
questions in an easy-to-understand manner.
Maintain a publicly accessible information
repository. An information repository is simply
a collection of documents describing the facili-
ty and its activities. It can include background
information on the facility, the involvement
plan (if developed), permits to manage waste
on-site, fact sheets, and copies of relevant
guidance and regulations. The repository
should be in a convenient, publicly accessible
place. Repositories are often maintained on-
site in a public "reading room" or off-site at a
public library, town hall, or public health
office. Industry should publicize the existence,
location, and hours of the repository and
update the information regularly.
Develop exhibits that explain facility oper-
ations. Exhibits are visual displays, such as
maps, charts, diagrams, or photographs,
accompanied by brief text. They provide
technical information in an easily under-
standable way and give an opportunity to
illustrate issues of concern creatively and
informatively. When developing exhibits,
identify the target audience, clarify which
issue or aspect of the facility's operations will
be the exhibit's focus, and determine where
the exhibit will be displayed. Public libraries,
convention halls, community events, and
shopping centers are all good, highly visible
locations for an exhibit.
Use publications and mailing lists of estab-
lished local organizations. Existing groups
and publications often provide access to
established communication networks. Take
advantage of these networks to minimize the
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time and expense required to develop mailing
lists and organize meetings. Civic or environ-
mental groups, rotary clubs, religious organi-
zations, and local trade associations might
have regular meetings, newsletters, newspa-
pers, or magazines, as well as mailing lists,
that could be useful in reaching interested
members of the community.
understand the nature of any uncertainties
associated with the analysis. This section
provides a general overview of the scientific
principles underlying the methods for quanti-
fying cancer and noncancer risk assessment.
Ultimately, understanding the scientific prin-
ciples will lead to more effective use of the
guidance tools.
III. Understanding
Risk Assessment
Environmental risk communication skills
are critical to successful partnerships between
industry, the public, and other stakeholders.
As more environmental management deci-
sions are made on the basis of risk, it is
increasingly important for all interested par-
ties to understand the science behind risk
assessment. Encouraging public participation
in environmental decision-making means
ensuring that all interested parties understand
the basic principles of risk analysis and can
converse equally on the development of
assumptions that underlie the analysis.
A. Introduction to Risk
Assessment
This guidance document provides simple-
to-use risk assessment tools that can assist in
determining the appropriate waste manage-
ment practices for surface impoundments,
landfills, waste piles, and land application
units. The guidance tools are based on pre-
dicting potential human health impacts from
a waste management unit by modeling two
possible exposure pathways: releases through
volatile air emissions and contaminant migra-
tion into ground water. Although applying
the guidance tools is simple, it is still essen-
tial to understand the basic concepts of risk
analysis to be able to interpret the results and
B. Types of Risk
Risk is a concept used to describe situa-
tions or circumstances that pose a hazard to
people or things they value. People
encounter a myriad of risks during common
everyday activities, such as driving a car,
investing money, and undergoing certain
medical procedures. By definition, risk is
comprised of two components: the probabili-
ty that an adverse event will occur and the
magnitude of the consequences of that
adverse event. As such, in capturing these
two components, risk is typically stated in
terms of the probability (e.g., one chance in
one million) of a specific harmful "endpoint"
(i.e., accident, fatality, cancer).
In the context of environmental manage-
ment, and in the context of this section in the
guidance document, risk is defined as the
probability or likelihood that public health
may be impacted from exposure to chemicals
contained in waste management units. The
risk endpoints resulting from the exposure are
typically grouped into two major consequence
categories: cancer risk and noncancer risk.
As implied, the cancer risk category cap-
tures risks associated with exposure to chemi-
cals that may initiate cancer. To determine a
cancer risk, one must calculate the probability
of an individual developing any type of cancer
during his or her lifetime from exposure to
carcinogenic hazards. Cancer risk is generally
expressed in scientific notation; in this nota-
tion, the chance of 1 person in 1,000,000 of
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developing cancer would be expressed as
1 x lO^or IE6. The noncancer risk category is
essentially a catch-all category for the remain-
ing health effects resulting from chemical
exposure. Noncancer risk encompasses a
diverse set of effects or endpoints, such as
weight loss, enzyme changes, reproductive
and developmental abnormalities, and respira-
tory reactions. Noncancer risk is generally
assessed by comparing the exposure or aver-
age intake of a chemical with a corresponding
reference (a health benchmark), thereby creat-
ing a ratio. The ratio so generated is referred
to as the hazard quotient (HQ). An HQ that is,
greater than 1 indicates that the exposure
level is above the protective level of the health
benchmark, whereas, an HQ less than 1 indi-
cates that the exposure is below the protective
level established by the health benchmark.
It is important to understand that exposure
to a chemical does not necessarily result in an
adverse health effect. A chemical's ability to
initiate a harmful health effect depends on
the toxicity of the chemical as well as the
route (i.e., ingestion, inhalation) and dose
(the amount that a human intakes) of the
exposure. Health benchmark values are used ;
to quantify a chemical's possible toxicity and
ability to induce a health effect, and are
derived from toxicity data. They represent a
"dose-response" estimate that relates the like-
lihood and severity of adverse health effects
to exposure and dose. The health benchmark
is used in combination with an individual's
exposure level to determine if there is a risk.
Because individual chemicals generate differ-
ent health effects at different doses, bench-
marks are chemical specific; additionally,
since health effects are related to the route of:
exposure and the timing of the exposure,
health benchmarks are specific to the route i
(ingestion or inhalation) and the duration
(acute, subchronic, or chronic) of the expo-
sure. The definitions of acute, subchronic and
chronic exposures vary, but acute typically
implies an exposure of less than one day, sub-
chronic generally indicates an exposure of a
few weeks to a few months, and chronic
exposure can span periods of several months
to several years.
The health benchmark for carcinogens is
called the cancer slope factor. A cancer slope
factor (CSF) is defined as the upper-bound
estimate of the probability of a response per
unit intake of a chemical over a lifetime and
is expressed in units of (mg/kg-d)'1. The slope
factor is used to estimate an upper-bound
probability of an individual developing can-
cer as a result of a lifetime of exposure to a
particular concentration of a carcinogen.
A reference dose (RfD) for oral exposure
and reference concentration (RfC) for inhala-
tion exposure are used to evaluate noncancer
effects. The RfD and RfC are estimates of
daily exposure levels to individuals (including
sensitive populations) that are likely to be
without an appreciable risk of deleterious
effects during a lifetime and are expressed in
units of mg/kg-d (RfD) or mg/m3 (RfC).
Most health benchmarks reflect some
degree of uncertainty because of the lack of
precise toxicological information on the peo-
ple who might be most sensitive (e.g., infants,
elderly, and nutritionally or immunologically
Example of Health Benchmarks
Acrylonitrile
Chronic:
inhalation CFS: 0.24(mg/kg/d)4
oral CFS: 0.54 (mg/kg/d)-1
RIG: 0.002 mg/rn3
R£D:0.001 mg/kg/d
Subchronic:
RfC: 0.02 mg/m'
Acute:
ATSDR MRL: 0.22 mg/m3
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compromised) to the effects of
hazardous substances. There is
additional uncertainty because
most benchmarks must be based
on studies performed on animals,
as relevant human studies are
lacking.
There are several sources for
obtaining health benchmarks,
some of which are summarized in
the text box. Note that from time-
to-time benchmark values may be
revised to reflect new toxicology
data on a chemical. In addition,
because many states may have
developed their own toxicology
benchmarks, both the ground-
water and air tools in this guid-
ance enable a user to input an
alternative benchmark to those
that are provided.
C. Assessing Risk
Typically risk is estimated using
the organized process of evaluat-
ing scientific data known as risk
assessment. Risk assessment ulti-
mately serves as guidance for
making management decisions by
providing one of the inputs to the
decision making process. Risk
assessment furnishes beneficial
information for a variety of situa-
tions, such as determining the
appropriate pollution control sys-
tems for an industrial site, pre-
dicting the appropriateness of dif-
ferent waste management options
or alternative waste management
unit configurations, or identifying
exposures that may require addi-
tional attention.
Sources for Health Benchmarks
System (IRIS) The Integrated
Risk Information System (IRIS) is the Agency's official, reposi-
tory of Agency-wide consensus chronic human health risk
information. IRIS-is an EPA data base containing Agency con-
sensus scientific positions on potential adverse human health
effects that may result from'chronic (or lifetime) exposure to .
environmental contaminants. IRIS information includes the
reference dose for rioncancer'health effects resulting from
oral exposure, the.reference concentration for noncancer .
health effects resulting from inhalation exposure, and the car-
cinogen assessment for both oral and inhalation exposure.
Health Effects Assessmem Sumniary Tables (HEAST)
HEAST is a comprehensive listing compiled by the EPA , .,
consistmg'of risk assessment -information relative to oral
and inhalation routes for chemicals. HEAST benchmarks
are considered secondary to those contained in IRIS.
Although the entries in HEAST have undergone review and
have the concurrence of individual agency program offices,
they have either not been reviewed as extensively as those
in IRIS or they dp, not have as complete a data set as is
.required for acchemical to be listed in IRIS.
Agency for Toaac Substances and Disease Registry (ATSPK)
The Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA), .requires that the
Agency for Toxic Substances and Disease Registry (ATSDR)
develop jointly with the EPA, in order of priority, a list of
hazardous substances most commonly found at facilities on
the CERCLA National Priorities List; prepare lexicological
profiles for each substance included on the priority list of
hazardous substances; ascertain significant human exposure
levels (SHELs) for hazardous substances in the environment,
and the associated acute, subchronic, and chronic health
effects; and assure the initiation of a research program to fill
identified data needs associated with the substances. The
ATSDR Minimal Risk Levels (MRLs) were developed as an
initial response to the mandate. MRLs are based on non-
cancer health effects only and are not based on a considera-
tion of cancer effects. MRLs are derived for acute (1-14 days),
intermediate (15-364 days), and.chronic (365 days and
longer) exposure durations, for the oral and inhalation routes
of exposure.
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The risk-evaluation process involves data
collection activities, such as identifying and
characterizing the source of the environmen-
tal pollutant, determining the transport of
the pollutant once it is released into the
environment, determining the pathways of
human exposure, and identifying the extent
of exposure for individuals or populations at
risk. Performing a risk assessment is complex
and requires knowledge in a number of sci-
entific disciplines. Experts in several areas,
such as toxicology, geochemistry, environ-
mental engineering, and meteorology, may be
involved in performing a risk assessment.
For the purpose of this section, and for
brevity, the basic components important to
consider when assessing risk are summarized
in three main categories listed below. A more
extensive discussion of these components
can be found in the references listed at the
end of this section.
The three main categories are:
1. Hazard Identification: identifying and
characterizing1 the source of the
potential risk (e.g., chemicals man-
aged in a waste management unit).
2. Exposure Assessment: determining ,
the accessibility or avenues from the
source to an individual (i.e., exposure
pathways and,exposure routes).
3. Risk Characterization: integrating the
results of the exposure assessment
with information on who is potential-
ly at risk (e.g., location of the person,
body weights, etc.) and toxicity infor-
mation on the chemical.
1. Hazard Identification
For the purpose of this guidance docu-
ment, the source of the potential risk has
already been identified: waste management
units. However, there must be a release of
chemicals from a waste management unit for:
there to be exposure and risk. Chemicals may
be released from waste management units by
a variety of processes, including volatilization
(where chemicals in vapor phase are released
to the air), leaching to ground water (where
chemicals travel through the ground to a
ground-water aquifer), particulate emission
(where chemicals attached to particulate mat-
ter are released in the air when the particulate
matter becomes airborne), and run-off and
erosion (where chemicals in soil water or
attached to soil particles move to the sur-
rounding area).
To consider these releases in a risk assess-
ment, information characterizing the waste
management unit is needed. Critical parame-
ters include the size of the unit and its loca-
tion. For example, larger units tend to pro-
duce larger releases. Units located close to the
water table might produce greater releases to
ground water than units located further from
the water table. Units located in a hot, dry,
windy climate may produce greater volatile
releases than units in a cool, wet, non-windy
climate.
2. Exposure Assessment:
Pathways, Routes, and
Estimation
Individuals and populations may come
into contact with environmental pollutants by
a variety of exposure mechanisms and
processes. The mere presence of a hazard,
such as toxic chemicals in a waste manage-
ment unit, does not denote the existence of a
risk. Exposure is the bridge between what is
considered a hazard and what actually pre-
sents a risk. Assessing exposure involves
determining the pathways and extent of
human contact with toxic chemicals. The
magnitude, frequency, duration, and route of
exposure to a substance must be considered
when collecting all of the data necessary to
construct a complete exposure assessment.
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The steps for performing an exposure
assessment include identifying the potentially
exposed population (receptors); pathways of
exposure; environmental media that transport
the contaminant; contaminant concentration at
a receptor point; and receptor's exposure time,
frequency and duration. The output of the
exposure assessment is a numerical estimate of
exposure and intake of a chemical by an indi-
vidual. The intake information is then used in
concert with chemical-specific health bench-
marks to quantify risks to human health.
Before gathering these data, it is important
to understand what information is necessary
for conducting an adequate exposure assess-
ment and what type of work may be
required. Exposures are commonly deter-
mined by using mathematical models of
chemical fate and transport to determine
chemical movement in the environment in
conjunction with models of human activity
patterns. The information required for per-
forming the exposure assessment
includes site-specific data such as
soil type, meteorological condi-
tions, ground-water pH, and loca-
tion of the nearest receptor.
Information must be gathered for
the two components of exposure
assessment: exposure
pathways/routes and exposure
quantification/estimation.
a. Exposure
Pathways/Routes
An exposure pathway is the
course the chemical takes from its
source to the individual or popula-
tion it reaches. Chemicals cycle in
the environment by crossing
through the different types of media
which are considered exposure
pathways: air, soil, ground water,
surface water, and biota (Figure
1). As a result of this movement, a chemical
can be present in various environmental
media, and human exposure often results from
multiple sources. The relative importance of an
exposure pathway depends on the concentra-
tion of a chemical in the relevant medium and
the rate of intake by the exposed individual. In
a comprehensive risk assessment, the risk
assessor identifies all possible site-specific
pathways through which a chemical could
move and reach a receptor. This guidance doc-
ument provides tools to model the transport
and movement of chemicals through two envi-
ronmental pathways: air and ground water.
The transport of a chemical in the environ-
ment is facilitated by natural forces: wind and
water are the primary physical processes for
distributing contaminants. For example,
atmospheric transport is frequently caused by
ambient wind. The direction and speed of the
wind determine where a chemical can be
found. Similarly, chemicals found in surface
Figure 1. Multiple Exposure Pathways/Routes (National Research
Council, "Frontiers in Assesssing Human Exposure," 1991)
1-11
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water and ground water are car-
ried by water currents or sedi-
ments suspended in the water.
The chemistry of the contami-
nants and of the surrounding
environment, often referred to as
the "system," also plays a signifi-
cant role in determining the ulti-
mate distribution of pollutants in
the various types of media.
Physical-chemical processes,
including dissolution/precipita-
tion, volatilization, and photolytic
and hydrolytic degradation, as
well as sorption and complexa-
tion, can influence the distribu-
tion of chemicals among the dif-
ferent environmental media and
the transformation from one
chemical form to another.1 An
important component of creating
a conceptual model for perform-
ing a risk assessment is the identi-
fication of the relevant processes
that occur in a system. These
complex processes depend on the
conditions at the site and specific
chemical properties.
Whereas the exposure pathway
dictates the means by which a
contaminant can reach an indi-
vidual, the exposure route is the
way in which that chemical enters
the body. To generate a health
effect, the chemical must come in
contact with the body. In environ-
mental risk assessment, three
exposure routes are generally con-
sidered: ingestion, inhalation, and
dermal absorption. As stated ear-
lier, the toxicity of a chemical is
specific to the dose received and
its means of entry into the body.
For example, a chemical that is
inhaled may prove to be toxic and
Key Chemical Processes
Sorption: the ability of a-chemical to partition between the
liquid and solid phase by determining its affinity for adher-
ing to other solids in the system such as soils and sediment.
The amount of chemical that "sorbs" to solids and does not
move through the environment is dependent upon the char-
acteristics of the chemical, the characteristics of the sur-
rounding soils and sediments, and the quantity of the chemi-
cal. A sorption coefficient is the measure of a chemical's abili-
ty to sorb. If too much of the chemical is present, the avail-
able binding sites on soils and sediments will be filled and
sorption will not continue.
DissolMon/prec^itation: the extent to which a substance
will be found in a soluble form versus a solid form. In disso-
lution a chemical is taken into solution; precipitation is the
formation of an insoluble solid. These processes are a func-
tion of the nature of the chemical and its surrounding envi-
ronment and are dependent on properties such as tempera-
ture and pH. A chemical's solubility is characterized by a sol-
ubility product. Chemicals that tend to volatilize rapidly are
not highly soluble.
Degradation: the propensity and extent a chemical will break
down into other substances in the environment. Some degra-
dation processes include biodegradation, hydrolysis, and
photolysis. Not all degradation products have the same risk
as the "parent" compound. Some chemicals can break into
"daughter" products that are more harmful than the parent
substance. In performing a risk assessment it is important to
consider what the daughter products of degradation may be.
Bioaccumulation: the ability of a substance to be taken up
and stored in an organism. Typically, the concentrations of
the substance in the organism exceed the concentrations in
the environment since the organism will store the substance
and not excrete it. A bioaccumulation factor is associated
with each chemical.
Volatility: the ability of a compound to partition into a
gaseous state. The volatility of a compound is dependent on
its water solubility and vapor pressure. The extent to which a
chemical can partition into air is described by one of two
constants: Henry's Law or Rauok's Law. Other factors that are
important to volatility are atmospheric temperature and
waste mixing.
'Kolluru, Rao (1996)
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result in a harmful health effect, whereas the
same chemical may cause no reaction if
ingested, or vice-versa. This phenomenon is
due to the differences in mechanisms once a
chemical enters the body. A chemical that is
inhaled reaches the lungs and enters the
blood system. A chemical that is ingested
may pass through the liver before entering
the blood system, where it may be metabo-
lized into a different chemical that may result
in a health effect or into another chemical
that is soluble and can be excreted.
Some contaminants can also be absorbed
by the skin. The skin is not very permeable
and usually provides a sufficient barrier
against most chemicals. However, some
chemicals can pass through the skin in suffi-
cient quantities to induce severe health
effects. An example is carbon tetrachloride,
which is readily absorbed through the skin
and at certain doses can cause severe liver
damage. The dermal route is typically consid-
ered in worker scenarios in which the worker
is actually performing activities that involve
skin contact with the chemical of concern.
The tools provided in this guidance docu-
ment do not address the dermal route of
exposure.
b. Exposure
Quantification/Estimation
Once appropriate fate and transport mod-
eling has been performed for each pathway,
providing concentrations of a chemical at an
exposure point, the chemical intake by a
receptor must be quantified. Quantifying the
frequency, magnitude, and duration of expo-
sures that result from the transport of a
chemical to an exposure point is critical to
the overall assessment. For this step, the risk
assessor calculates the chemical-specific expo-
sures for each exposure pathway identified.
Exposure estimates are expressed in terms of
the mass of a substance in contact with the
body per unit body weight per unit time
(e.g., milligrams of a chemical per kilogram
body weight per day, also expressed as
mg/kg-day).
The exposure quantification process
requires two main areas of information gather-
ing: the receptor activity patterns and the bio-
logical characteristics of receptors (body
weight, inhalation rate). Activity patterns and
biological characteristics dictate the amount of
a constituent that a receptor may intake and
the dose that is received per kilogram of body
weight. Chemical intake values are calculated
using equations that include variables for
exposure concentration, contact rate, expo-
sure frequency, exposure duration, body
weight, and exposure averaging time. The val-
ues of some of these variables depend on the
site conditions and the characteristics of the
potentially exposed population. For example,
the rate of oral ingestion of contaminated food
is different for different subgroups of recep-
tors, which might include adults, children,
area visitors, subsistence farmers, and subsis-
tence fishers. Children typically drink greater
quantities of milk each day than adults per
unit body weight. A subsistence fisher would
be at a greater risk than another area resident
from the ingestion of contaminated fish.
Additionally, a child may have a greater rate of
soil ingestion than an adult due to playing
outdoors or hand-to-mouth behavior patterns.
The activities of individuals also determine the
duration of exposure. A resident may live in
the area for 20 years and be in the area for
more than 350 days each year. Conversely, an
area visitor or a worker will have shorter
exposure times. After the intake values have
been estimated, they should be organized by
population as appropriate (i.e., children, adult
residents) so that the results in the risk char-
acterization can be reported for each popula-
tion group. To the extent feasible, site-specific
values should be used for estimating the
exposures; otherwise, default values suggested
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1-14
by the EPA in The Exposure Factors Handbook
(EPA, 1995) may be used.
3. Risk Characterization
In the risk-characterization process, the toxi-
city information (slope factors, reference doses)
and the results of the exposure assessment
(estimated intake or dose of potentially
exposed populations) are integrated to arrive at
quantitative estimates of cancer and noncancer
risks. To characterize the potential noncarcino-
genic effects, comparisons are made between
projected intake levels of substances and toxic-
ity values. To characterize potential carcino-
genic effects, probabilities that an individual
will develop cancer over a lifetime are estimat-
ed from projected intake levels and chemical-
specific dose-response relationships. This pro-
cedure is the final calculation step. This step
determines who is likely to be affected and
what the likely affects are. Because of all the
assumptions inherent in deriving a risk, a risk,
characterization cannot be considered com-
plete unless the numerical expressions of risk
are accompanied by explanatory text interpret-
ing and qualifying the results. The risk charac-
terization step for carcinogens and noncarcino-
gens is different and is shown in the text box
below.
Another consideration during the risk-
characterization phase are cumulative effects.
Calculating Risk
Cancer Risks:
Incremental risk of cancer = average
daily dose (mg/kg-day) * slope factor
(mg/kg-day)-1
Non-Cancer Risks
Hazard quotient = exposure or intake
(mg/kg-day) or (mg/m3)/ RfD (mg/kg-day)
or RfC (mg/m3)
A given population may be exposed to multi-
ple chemicals from several exposure routes
and sources. For example, multiple con-
stituents may be managed in a single waste
management unit, and by considering one
chemical at a time the risks associated with
the waste management unit may be underes-
timated. The EPA (1989a) has developed
guidance outlined in the Risk Assessment
Guidance for Superfund, Volume I to assess the
overall potential for cancer and noncancer
effects posed by multiple chemicals. The risk
assessor, facility manager, and other interest-
ed parties should determine the appropriate-
ness of adding the risk contribution of each
chemical for each pathway to derive a cumu-
lative cancer risk or noncancer risk. The pro-
Cancer Risk Equation for Multiple
Substances
Riskr = ZRisk,
where:
Riskr _ tne lotaj cancer risk, expressed as a
unitless probability
Risk. = the risk estimate for the ilh substance
cedures for adding risks differ for carcino-
genic and noncarcinogenic effects.
The cancer-risk equation described in the
box above estimates the incremental individ-
ual lifetime cancer risk for simultaneous expo-
sure to several carcinogens and is based on
EPA (1989a) guidance. The equation com-
bines risks by summing the risks to a receptor
from each of the carcinogenic chemicals.
To assess the overall potential for noncar-
cinogenic effects posed by more than one
chemical, a hazard index (HI) approach was
developed by the EPA. The approach
assumes that the magnitude of an adverse
health effect is proportional to the sum of the
hazard quotients of each of the chemicals
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Getting Started—Building Partnerships
investigated. Assessing cumulative effects
from noncarcinogens is more difficult and
contains a greater amount of uncertainty. As
discussed earlier, noncarcinogenic risk covers
a diverse set of health effects and different
chemicals will have different effects. In keep-
ing with EPA's Risk Assessment Guidance, haz-
ard quotients should only be added for
chemicals that have the same critical effect
(e.g., both chemicals effect the liver or both
initiate respiratory distress.) As a result, an
extensive knowledge of toxicology is needed
to sum the hazard quotients to produce a
hazard index. Segregation of hazard indices
by effect and mechanism of action can be
complex, time-consuming, and will have
some degree of uncertainty associated with it.
This analysis is not simple and should be per-
formed by a toxicologist.
D. Results
The results of a risk assessment provide a
basis for making decisions but are only one ele-
ment of input into the decision process. The
risk assessment does not constitute the only
basis for management action. Other factors are
also important, such as technical feasibility of
options, public values, and economics.
Understanding and interpreting the results for
the purpose of making decisions also requires a
thorough knowledge of the assumptions that
were applied during the risk assessment.
Ample documentation should be constructed
to define the scenarios that were evaluated for
the risk analysis and any uncertainties there
may be in the estimate. Some of the informa-
tion that should be considered for inclusion in
the risk assessment documentation may be: key
site-related information such as contaminants
evaluated, a description of the risks present
(i.e., cancer, noncancer), the level of confidence
in the information used in the assessment, the
major factors driving the site risks, and the
characteristics of the exposed population. The
results of a risk assessment are essentially
meaningless without the information on how
they were generated.
IV. Information on
Environmental
Releases
Under the Emergency Planning and
Community
Right-to-Know
Act (EPCRA) of
1986, facilities
in a designated
Standard
Industry Code
(see 40 CFR §372.22) with more than 10
employees that manufacture or process more
than 25,000 pounds, or otherwise use more
than 10,000 pounds, of a Toxic Release
Inventory (TRI)-listed chemical are required to
report their environmental releases annually to
EPA and state governments. Environmental
releases include the disposal of wastes in land-
fills, surface impoundments, land application
units, and waste piles. EPA compiles these data
in the TRI database. TRI data are also being
made available through public libraries and
reports. You may wish to include TRI data in
the facility's information repository.
EPCRA is based on the belief that citizens
have a right to know about potential environ-
mental risks caused by facility operations in
their communities, including those posed as a
result of waste management. TRI data, there-
fore, provide yet another way for residents to
learn about the waste management activities
taking place in their neighborhood and to
take a more active role in decisions that
potentially affect their health and environ-
ment. More information on TRI and access to
TRI data can be obtained from EPA's Web site
.
1-15
-------
Getting Started—Building Partnerships
a
a
a
a
a
a
a
a
a
Building Partnerships Action Items
Develop exhibits that provide a better understanding of facility operations.
Identify potentially interested/affected people.
Notify the state and public about new facilities or significant changes in facility
operating plans.
Set up a public meeting for input from the community.
Provide interpreters for public meetings.
Make knowledgeable and responsible people available for sharing information.
Develop an involvement plan based on information gathered in previous steps.
Provide access to the facility and to information about its operations.
Maintain a publicly accessible information repository or on-site reading room.
1-16
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Getting Started—Building Partnerships
Resources
Chemical Manufacturers Association. 1994-1995. Ten Elements of Responsible Care:
Understanding the Initiative Through Member and Partner Progress.
Chemical Manufacturers Association. 1995. A Plant Manager's Introduction to Environmental
Justice.
Council in Health and Environmental Science, ENVIRON Corporation. 1986. Elements of
Toxicology and Chemical Risk Assessment.
Executive Order 12898. 1994. Federal Actions to Address Environmental Justice in Minority
Populations and Low-income Populations. February.
Holland, C.D., and R.S. Sielken, Jr. 1993. Quantitative Cancer Modeling and Risk Assessment.
Kolluru, Rao, Steven Bartell, et al. 1996. Risk Assessment and Management Handbook: For
Environmental, Health, and Safety Professionals.
Louisiana Department of Environmental Quality. 1994. Final Report to the Louisiana Legislature on
Environmental Justice.
Lu, Frank C. 1996. Basic Toxicology: Fundamentals, Target Organs, and Risk Assessment.
National Research Council. 1983. Risk Assessment in the Federal Government: Managing the
Process.
Public Participation and Accountability Subcommittee of the National Environmental Justice
Advisory Council (A Federal Advisory Committee to the U.S. EPA). 1996. The Model Plan for
Public Participation. November.
Texas Natural Resource Conservation Commission. 1993. Texas Environmental Equity and Justice
Task Force Report: Recommendations to the Texas Natural Resource Conservation Commission.
Travis, C.C. 1988. Carcinogenic Risk Assessment.
U.S. EPA. 1996. RCRA Public Involvement Manual. EPA530-R-96-007.
U.S. EPA. 1996. 1994 Toxics Release Inventory: Public Data Release, Executive Summary.
EPA745-S-96-001.
1-17
-------
Getting Started—Building Partnerships
Resources (cont.)
U.S. EPA. 1995. Decision-maker's Guide to Solid Waste Management, Second Edition. EPA530-R-95-023.
U.S. EPA. 1995. The Exposure Factors Handbook. EPA600-P-95-002A-E.
U.S. EPA. 1995. OSWER Environmental Justice Action Agenda. EPA540-R-95-023.
U.S. EPA. 1992. Environmental Equity: Reducing Risk for all Communities. EPA230-R-92-008A.
U.S. EPA. 1990. Sites for our Solid Waste: A Guidebook for Effective Public Involvement. EPA530-
SW-90-019.
U.S. EPA. 1989. Chemical Releases and Chemical Risks: A Citizen's Guide to Risk Screening.
EPA560-2-89-003.
U.S. EPA. 1989. Risk Assessment Guidance for Superfund. EPA540-1-89-002.
U.S. Government Accounting Office. 1995. Hazardous and Nonhazardous Waste: Demographics of
People Living Near Waste Facilities. GAO/RCED-95-84.
Ward, R. 1995. Environmental Justice in Louisiana: An Overview of the Louisiana Department of
Environmental Quality's Environmental Justice Program.
Western Center for Environmental Decision-Making. 1996. Public Involvement in Comparative Risk
Projects: Principles and Best Practices: A Source Book for Project Managers.
1-18
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Part I
Getting Started
Chapter 2
Characterizing Waste
-------
Contents
I. Waste Characterization Through Process Knowledge '. 2-1
II. Waste Characterizaton Through Leachate Testing 2-2
A. Sampling and Analysis Plan. 2-3
1. Representative Waste Sampling 2-4
2. Representative Waste Analysis , 2-6
B. Leachate Test Selection 2-6
1. Toxicity Chracteristics Leaching Procedure : 2-7
2. Synthetic Precipitation Leaching Procedure (SPLP) 2-8
3. Multiple Extraction Procedure (MEP) 2-9
4. Shake Extraction of Solid Waste with Water or Neutral Leaching Procedure 2-9
HI. Waste Characterizaton of Volatile Organic Emissions 2-10
Waste Characterizaton Action Items 2-11
Resources : 2-12
-------
Getting Started—Characterizing Waste
Characterizing Waste
Understand the industrial processes that generate a waste.
Determine the waste's physical and chemical properties. Quantify
constituent leaching to facilitate ground-water risk analysis.
Quantify total constituent concentrations to facilitate air emission
analysis, and consideration of pollution prevention and treatment.
Understanding the physical and
chemical properties of a waste
and sampling and analysis proce-
dures is the cornerstone upon
which subsequent steps in this
guidance are built. Knowledge of the physical
and chemical properties of the waste is crucial
in identifying waste reduction opportunities. It
is necessary in gauging what risks a waste may
pose to surface water, ground water, and air. It
drives the selection of a liner or the choice of
land application methods. It is needed to deter-
mine which constituents to test for if conduct-
ing ground-water monitoring. Use knowledge
of waste generation processes, analytical testing,
or some combination of the two to estimate
waste constituent concentrations. Over time
when changes are made to the industrial
processes or waste management practices, it
This chapter will help address the
following questions:
• Can process knowledge be used to char-
acterize waste?
• What constituent concentrations
should be quantified?,
• What type of leachate test should be
used? '• ""• "•'-,, :
may be necessary to recharacterize a waste. No
matter which approach is used in characterizing
a waste, the important goal is to maximize the
knowledge available to make the important
decisions described in later chapters of this
guidance.
I. Waste
Characterization
Through Process
Knowledge
A waste characterization begins with an
understanding of the industrial processes that
generate a waste. As a starting point, obtain
information about the waste itself such as the
physical state of the waste, the volume, and
the composition. In addition, obtain enough
2-1
-------
Getting Started—Characterizing Waste
2-2
information about the process to enable prop-
er characterization of the waste. Many indus-
tries have thoroughly tested and characterized
their wastes over time. Check with trade
associations to see if the appropriate informa-
tion is available for a particular waste.
The following examples of process knowl-
edge may assist in waste characterization by
providing information on waste constituents
and potential concentrations:
• Chemical engineering designs/plans for .
the process, showing process input chem-
icals, expected primary and secondary
chemical reactions, and products;
• Material Safety Data Sheets (MSDSs).
Note, however, that not all MSDSs con-
tain information on all constituents found
in a product;
• Manufacturer's literature;
• Previous waste analyses;
• Literature on similar processes; and
• Preliminary testing results, if available.
A materials balance exercise using process :
knowledge may be useful in understanding
where wastes are generated within a process,
and estimating the quantity of chemicals in
such wastes. In a material balance, calculate
all input streams, such as raw materials fed
into the processes, and all output streams,
such as products produced and waste gener-
ated. Material balances can assist in estimat-
ing concentrations of waste constituents
where analytical test data are limited.
Characterizing waste using material balances
can require considerable effort and expense,
but may assist in developing a more complete
picture of candidate waste generation
process(es). Flow diagrams are generally pre-
pared to identify important process steps and
sources where wastes are generated.
A thorough assessment of a production
processes can also serve as the starting point
for a facility-wide waste reduction, recycling,
or pollution prevention effort. Such an assess-
ment will provide the information base to
explore many opportunities to reduce or
recycle the volume or toxicity of wastes.
Check the integrating pollution prevention,
recycling, and treatment chapter for ideas,
tools, and references on how to proceed.
II. Waste
Characterization
Through
Leachate Testing
The intent of leaching and extraction tests is
to estimate the release of waste constituents
into ground water. The importance of estimat-
ing potential constituent concentrations that
may leach to ground water is underscored by
the fact that the ground water software model,
Industrial Waste Management Evaluation Model,
(IWEM), developed for this guidance docu-
ment uses expected leachate concentrations to
develop recommended liner system designs.
If the total concentration of all the con-
stituents in a waste, has been estimated using
process or industry knowledge, estimates of
the maximum possible concentration of these
constituents in leachate can be made using
the dilution ratio of the leachate test to be
performed. For example, the Toxicity
Characteristic Leachate Procedure (TCLP)
does allow for a total constituent analysis in
lieu of the TCLP extraction. If a waste is 100
percent solid, as defined by the TCLP
method, then the results of the total composi-
tional analysis may be divided by twenty to
convert the total results into the maximum
leachable concentration. This factor is derived
from the 20:1 liquid to solid ratio employed
in the TCLP. If a waste has filterable liquid,
.
-------
Getting Started—Characterizing Waste
then the concentration of each phase (liquid
and solid) must be determined. The following
equation may be used to calculate this value:1
[A x B] + [C x D]
B + [20 (L/kg) x D]
Where:
A = Concentration of the analyte in liquid
portion of the sample (mg/L)
B = Volume of the liquid portion of the sam-
ple (L).
C = Concentration of the analyte in solid
portion of the sample (mg/kg)
D = Weight of the solid portion of the sam-
ple (kg)
E = Maximum theoretical concentration in
leachate (mg/L)
Because this is only a screening method for
identifying an upper-bound TCLP leachate
concentration, consult with the state agency to
determine whether process knowledge can be
used in lieu of leachate testing.
A. Sampling and Analysis
Plan
One of the more critical elements in proper
waste characterization is the plan for sampling
and analyzing the waste. The sampling plan is
usually a written document that describes the
objectives and details of the individual tasks of
a sampling effort and how they will be per-
formed. This plan should be carefully thought
out, well in advance of sampling. The more
detailed the sampling plan, the less opportuni-
ty for error or misunderstanding during sam-
pling, analysis, and data treatment.
To ensure that the sampling plan is
designed properly, a wide-range of personnel
should be consulted. The end user of the data,
an experienced member of the sampling team,
a senior analytical chemist, an engineer who
understands the manufacturing processes, a
statistician, and a quality assurance represen-
tative all need to be involved in the develop-
ment of a sampling plan. It is also wise to
consult the analytical laboratory to be used.
Development of sampling plans requires back-
ground information about the waste and the
unit, knowledge of the waste location and sit-
uation, decisions as to the types of samples
needed, and decisions as to the sampling
design required. The plan should address the
following considerations:
• Data quality objectives;
• Determination of a representative sample;
• Statistical methods to be employed in the
analyses;
• Waste generation and handling processes;
• Constituents/parameters to be sampled;
• Physical and chemical properties of the
waste;
• Accessibility of the unit;
• Sampling equipment, methods, and sam-
ple containers;
• Quality assurance and quality control
(e.g., sample preservation and handling
requirements);
• Chain-of-custody; and
• Health and safety of employees.
A number of these factors are discussed
below. Additional information on data quality
objectives and quality assurance and quality
control can be found in Test Methods for
Evaluating Solid Waste, Physical/Chemical
Methods—SW-846, Guidance for the Data Quality
Objectives Process (EPA600-R-96-055), Guidance
on Quality Assurance Project Plans (EPA600-R-
98-018), and Guidance for the Data Quality
Assessment: Practical Methods for Data Analysis
(EPA600-R-96-084).
'SW-846 Methods Team Home page at .
2-3
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Getting Started—Characterizing Waste
Prior to implementing a sampling
plan, it is often strategic to walk
through the sampling plan mentally,
starting with the preparation of the
equipment through the time when
samples are received at the laborato-
ry. This mental excursion should be
in as much detail as can be imag-
ined, because the small details are
the ones most frequently over-
looked.
1. Representative
Waste Sampling
The first step in any analytical
testing process is to obtain a sample
that is representative of the physical
and chemical composition of a
waste. The term "representative
sample" is commonly used to
denote a sample that has the proper-
ties and composition of the popula-
tion from which it was collected and
in the same proportions as found in
the population. This can be mislead-
ing unless dealing with a homoge-
nous waste from which one sample
can represent the whole population.
Because most industrial wastes are
not homogeneous, many different
factors should be considered in
obtaining samples that are collec-
tively representative of a waste.
Examples of factors that should be
considered include:
• Physical state of the waste. The
physical state of the waste affects
most aspects of a sampling effort.
The sampling device will vary
according to whether the sample
is liquid, gas, solid, or multipha-
sic. It will also vary according to
whether the liquid is viscous or
free-flowing, or whether the solid
More Information on Test Methods for Evaluating
Solid Waste, Physical/Chemical Methods—SW-846
EPA has begun replacing requirements mandating the
use of specific measurement methods or technologies
with a performance-based measurement system
(PBMS). The goals of PBMS is to reduce regulatory
burden and foster the use of innovative and emerging
technologies or methods. PBMS establishes what
needs to be accomplished, but does not prescribe
specifically how to do it. In a sampling situation, for
example, PBMS would establish the data needs, the
level of uncertainty acceptable for making decisions,
and the required supporting documentation, a specific
test method would not be prescribed. This approach
allows the analyst the flexibility to select the most
appropriate and cost effective test methods or tech-
nologies to comply with the criteria. Under PBMS, the
analyst is required to demonstrate the accuracy of the
measurement method using the specific matrix that is
being analyzed. SW-846 serves only as a guidance
document and starting point,
SW-846 provides state-of-the-art analytical test meth-
ods for a wide array of inorganic and organic con-
stituents, as well as procedures for field and laborato-
ry quality control, sampling, and characteristics test-
ing. The methods are intended to promote accuracy,
sensitivity, specificity, precision, and comparability of
analyses and test results.
For assistance with the methods described in SW-846,
call the EPA Method Information Communication
Exchange (MICE) Hotline at 703 821-4690 or send
an e-mail to mice@lan828.ehsg.saic.com.
SW-846 is available on line at:
A hard copy or CD-ROM version of SW-846 can be
purchased by calling the National Technical
Information Service (NTIS) at 703 487-4808.
2-4
-------
Getting Started—Characterizing Waste
is hard or soft, powdery, monolithic, or
clay-like.
• Composition of the waste. The samples
should represent the average concentra-
tion and variability of the waste in time
or over space.
• Waste generation and handling processes.
The waste generation and handling
processes to account for in sampling
efforts include: if the waste is generated
in batches; if there is a change in the raw
materials used in a manufacturing
process; if waste composition can vary
substantially as a function of process
temperatures or pressures; and if storage
time after generation may vary.
• Transitory events. Start-up, shut-down,
slow-down, and maintenance transients
can result in the generation of a waste
that is not representative of the normal
waste stream. If a sample was unknow-
ingly collected at one of these intervals,
incorrect conclusions could be drawn.
Consult with the state agency to identify any
legal requirements or preferences before begin-
ning sampling efforts. Refer to Chapter 9 of
SW-846 for detailed guidance on planning,
implementing, and assessing sampling events.
To ensure that the chemical information
obtained from a waste sampling efforts is accu-
rate, it must be unbiased and sufficiently pre-
cise. Accuracy is usually achieved by incorpo-
rating some form of randomness into the sam-
ple selection process and by selecting an appro-
priate number of samples. Since most industri-
al wastes are heterogeneous in terms of their
chemical properties, unbiased samples and
appropriate precision can usually be achieved
by simple random sampling. In this type of
sampling, all units in the population (essential-
ly all locations or points in all batches of waste
from which a sample could be collected) are
identified, and a suitable number of samples is
randomly selected from the population.
The appropriate number of samples to
employ in a waste characterization is at least
the minimum number of samples required to
generate a sufficiently precise estimate of the
true mean concentration of a chemical conta-
minant in a waste. A number of mathematical
formulas exist for determining the appropri-
ate number of samples depending on the sta-
tistical precision required.
The type of sampling plan developed will
vary depending on the sampling location.
Solid wastes contained in a landfill or waste
pile may be best sampled using a three-
dimensional random sampling strategy. This
involves establishing an imaginary three-
dimensional grid or sampling points in the
waste and then using random-number tables
or random-number generators to select points
for sampling. Hollow-stem augers combined
with split-spoon samplers are frequently
appropriate for sampling landfills.
If the distribution of waste components is
known or assumed for liquid or semisolid
wastes in surface impoundments, then a two-
dimensional simple random sampling strategy
may be appropriate. In this strategy, the top
surface of the waste is divided into an imagi-
nary grid, grid sections are selected using ran-
dom-number tables or random-number gener-
ators, and each selected grid point is then sam-
pled in a vertical manner along the entire
length from top to bottom using a sampling
device such as a weighted bottle, a drum thief,
or Coliwasa. If sampling is restricted due to the
size of the impoundment, the sampling strategy
should, at a minimum, take sufficient samples
to address the potential vertical anomalies in
the waste in order to be considered representa-
tive. This is because contained wastes tend to
display vertical, rather than horizontal, nonran-
dom heterogeneity due to settling of suspended
solids or denser liquid phases.
2-5
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Getting Started—Characterising Waste
To facilitate characterization efforts, con-
sult with the state agency and a qualified pro-
fessional to select a sampling plan and deter-;
mine the appropriate number of samples,
before beginning sampling efforts. Consider
conducting a waste-stream specific characteri-
zation in sufficient detail so that the informa-
tion can be used to conduct waste reduction ]
and waste minimization activities.
Additional information concerning sampling
plans, strategies, methods, equipment, and
sampling quality assurance and quality control
is available in chapters'9 and 10 in SW-846.
Electronic versions of these chapters have been
included on the CD-ROM for this guidance.
2. Representative Waste
Analysis
Once a representative sample has been col-
lected, it must be preserved to maintain the
physical and chemical properties that it pos-
sessed at the time of collection. Sample types,
types of sample containers, and their prepara-
tion and preservation methods are all impor-
tant in maintaining the integrity of the sam- ;
pie. The analytical chemist must develop an
analytical plan which is appropriate for the
sample to be analyzed, the constituents/para-
meters to be analyzed for, and the end use of
the information required. SW-846 contains
information on analytical plans and methods.
Additional references exist that are useful
sources of information regarding the selection
of analytical methods and quality
assurance/quality control procedures for vari-
ous compounds. One such web site is
.
B. Leachate Test Selection
Leaching tests are used to estimate potential
concentration or amount of waste constituents
that may leach from a waste to ground water.
Typical leaching tests use a specified leaching
fluid mixed with the solid portion of a waste
for a specified time. Solids are then separated
from the leaching solution and the solution is
tested for waste constituent concentrations.
The type of leaching test performed may vary
depending on the chemical, biological, and
physical characteristics of the waste, the envi-
ronment in which the waste will be placed, as
well as the recommendations or requirements
of the state agency
When selecting the most appropriate ana-
lytical procedures, consider at a minimum
the physical state of the sample using process
What leachate test is appropriate?
Selecting an appropriate leachate test can
be summarized in the following four steps.
1. Assess the physical state of the waste
using process and generator know-
ledge.
2. Assess the environment in which the
waste will be placed.
3. Consult with the state agency.
4. Select an appropriate leachate test
based on the above information.
and generator knowledge, the constituents to
be analyzed, detection limits, and the speci-
fied holding times of the analytical methods.
It may not be cost-effective or useful to con-
duct a test with detection limits at or greater
than the constituent concentrations in a
waste. There are several general categories of
phases in which samples can be categorized:
solids, aqueous, sludges, multiphase samples,
ground water, and oil and organic liquid.
Select a procedure that is designed for the
specific sample type.
After assessing the state of the waste, assess
the environment in which the waste will be
2-6
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Getting Started—Characterizing Waste
placed. For example, an acidic environment
may require a different test than a non-acidic
environment. If the waste management unit is
receiving only monofill, then the characteris-
tics of the waste will determine most of the
unit's conditions. Conversely, if wastes are
being co-disposed, then the conditions creat-
ed by the co-disposed wastes must be consid-
ered, including the constituents that may be
leached by the subject waste.
As described in the Phase IV LDR rule-
making (62 FR 25997; May 26, 1998), EPA is
undertaking a review of the TCLP test and
how it is used to evaluate waste leaching. EPA
anticipates that this review will examine the
effects of a number of factors on leaching and
on approaches to estimating the likely leach-
ing of a waste in the environment. These fac-
tors include pH, liquid to solid ratios, matrix
effects and physical form of the waste, effects
of non-hazardous salts on the leachability of
hazardous metal salts, and others. The effects
of these factors on leaching may or may not
be well reflected in the leaching tests current-
ly available. At the conclusion of the TCLP
review, EPA is likely to issue revisions to this
guidance that reflect a more complete under-
standing of waste constituent leaching under
a variety of management conditions.
Use a qualified laboratory when conduct-
ing analytical testing. The laboratory may be
in-house or independent. When using inde-
pendent laboratories, ensure that they are
qualified and competent to perform the
required tests. Some laboratories may be pro-
ficient in one test but not another. Consult
with the laboratory before finalizing the test
selection to ensure that it can be performed.
When using analytical tests that are not fre-
quently performed, additional quality assur-
ance and quality control practices may be
necessary to ensure that the tests were con-
ducted correctly and that the results are accu-
rate.
A brief summary of the TCLP and three
other commonly used leachability tests is
provided below. The complete procedures for
all of these tests are included in SW-846 or in
the Annual Book ofASTM Standards Volume
11.04. Appendix I provides a summary of
over 20 tests designed to help determine the
potential for contaminant release.2 Consult
with the state agency to identify the most
appropriate test and test procedures for the
waste and sample type.
1. Toxicity Characteristic
Leaching Procedure
The TCLP is the test required to determine
whether a waste is a toxicity characteristic
hazardous waste under RCRA in 40 CFR Part
261. The TCLP estimates the leachability of
certain hazardous constituents from solid
waste under a defined set of laboratory con-
ditions. It evaluates the leaching of metals,
volatile and semi-volatile organic compounds,
and pesticides from •wastes. The TCLP was
developed to simulate the leaching of con-
stituents into ground water under conditions
found in municipal solid waste (MSW) land-
fills. The TCLP does not simulate the release
of contaminants to nonground-water path-
ways. The TCLP is most commonly used by
EPA and state agencies to evaluate the leach-
ing potential of wastes, and to estimate likely
risks to ground water. The TCLP can be
found as EPA Method 1311 in SW-846.3 A
copy of Method 1311 has been included on
the CD-ROM for this guidance.
In the TCLP, liquid wastes (those contain-
ing less than 0.5 percent dry solid material)
are filtered through a glass fiber filter. Waste
samples containing solids and liquids are
handled by separating the liquids from the
solid phase, and then reducing solids to par-
ticle size. The solids are then extracted with
an acetate buffer solution. A liquid-to-solid
2EPA has only reviewed and evaluated those test methods found in SW-846. EPA has not reviewed or evalu-
ated the other test methods and cannot recommend any test methods other than those found in SW-846.
The TCLP was developed to replace the Extraction Procedure Toxicity Test method which is designated as
EPA Method 1310 in SW-846.
2-7
-------
Getting Started—Characterizing Waste
ratio of 20:1 by weight is used for an extrac-
tion period of 18 ± 2 hours. After extraction
the solids are filtered from the liquid extract,
and the liquid extract is combined with any
original liquid fraction of the wastes. Analyses
are then conducted on the filtrate and
leachate to determine the constituent concen-
trations. If the extract contains any of the
constituents listed in Table 1 of 40 CFR Part
261.24 at a concentration equal or greater
than the respective value in the Table, unless
excluded under §261.4, then the waste is
considered to be a hazardous waste under the
Toxicity Characteristic (TC).
Check with the state agency to determine
whether the TCLP is likely to be the best test
for evaluating the leaching potential of a .
waste, or if another test may better predict
the actual leaching of a waste. The TCLP test,
like other available leach tests, is designed to
simulate, or approximate one set of disposal
conditions and waste leaching that might
occur under those conditions. It is used by
EPA to classify waste as hazardous, and may
be conservative in some^ conditions (although
it has also apparently under predicted leach-
ing in other, rather extreme, conditions).
When disposal conditions are very different
from the TCLP test conditions, another test
may provide better short term, numerical esti-
mates of leaching.
2. Synthetic Precipitation
Leaching Procedure (SPLP)
The SPLP is currently used by several state
agencies to evaluate the leaching of con-
stituents from wastes, and has been designat-
ed as EPA Method 1312 in SW-846. The
SPLP was designed to estimate the leachabili-
ty of both organic and inorganic analytes pre-
sent in liquids, soils, and wastes. The SPLP
was originally designed to assess how clean a
soil was in EPA's clean closure program. The
federal hazardous waste program, however,
did not adopt it for use, but the test still may
estimate releases from wastes placed in a
landfill and subject to acid rain. There may
be, however, important differences between
soil as a constituent matrix and the matrix of
a generated industrial waste. A copy of
Method 1312 has been included on the CD-
ROM for this guidance.
The SPLP is very similar to the TCLP.
Waste samples containing solids and liquids
are handled by separating the liquids from
the solid phase, and then reducing solids to
particle size. The solids are then extracted
with a dilute sulfuric acid/nitric acid solution.
A liquid-to-solid ratio of 20:1 by weight is
used for an extraction period of 18±2 hours.
After extraction the solids are filtered from
the liquid extract, and the liquid extract is
combined with any original liquid fraction of
the wastes. Analyses are then conducted on
the filtrate and leachate to determine the con-
stituent concentrations.
The sulfuric acid/nitric acid extraction
solution used in the SPLP was selected to
simulate leachate generation, in part, from
acid rain. In both the SPLP and TCLP, oily,
and some paint wastes, may clog the filters
used to separate the extract from the solids
prior to analysis, resulting in under reporting
of the extractable constituent concentrations.
2-8
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Getting Started—Characterizing Waste
3. Multiple Extraction
Procedure (MEP)
The MEP is designed to simulate the leach-
ing that a waste will undergo from repetitive
precipitation of acid rain on a landfill to
reveal the highest concentration of each con-
stituent that is likely to leach in a real world
environment. Currently, the MEP is used in
EPA's de-listing program and has been desig-
nated as EPA Method 1320 in SW-846. A
copy of Method 1320 has been included on
the CD-ROM for this guidance.
The MEP can be used to evaluate liquid,
solid, and multiphase samples. Waste samples
are extracted according to the Extraction
Procedure (EP)Toxicity Test (Method 1310 of
SW-846). A copy of Method 1310 has been
included on the CD-ROM for this guidance.
The EP Test is very similar to the TCLP
Method 1311. In the EP, liquid wastes are fil-
tered through a glass fiber filter. Waste sam-
ples containing solids and liquids are handled
by separating the liquids from the solid
phase, and then reducing the solids to parti-
cle size. The solids are then extracted using
an acetic acid solution. A liquid-to-solid ratio
of 16:1 by weight is used for an extraction
period of 24 hours. After extraction the solids
are filtered from the liquid extract, and the
liquid extract is combined with any original
liquid fraction of the wastes. The solid por-
tions of the samples that remain after applica-
tion of Method 1310 are then re-extracted
using a dilute sulfuric acid/nitric acid solu-
tion. As in the SPLP, this fluid was selected to
simulate leachate generation, in part, from
acid rain. This time a liquid-to-solid ratio of
20:1 by weight is used for an extraction peri-
od of 24 hours. After extraction solids are
once again filtered from the liquid extract,
and the liquid extract is combined with the
original liquid fraction of the wastes. These
four steps are repeated eight additional times.
If the concentration of any constituent of
concern increases from the 7th or Slh extrac-
tion to the 9th extraction, the procedure is
repeated until these concentrations decrease.
The MEP is intended to simulate 1,000
years of freeze and thaw cycles and prolonged
exposure to a leaching medium. One advan-
tage of the MEP over the TCLP is that the
MEP gradually removes excess alkalinity in
the waste. Thus, the leaching behavior of
metal contaminants can be evaluated as a
function of decreasing pH, which increases
the solubility of most metals.
4. Shake Extraction of Solid
Waste with Water or
Neutral Leaching
Procedure
Shake Extraction of Solid Waste with Water,
or the Neutral Leaching Procedure, was devel-
oped by the American Society for Testing and
Materials (ASTM) to assess the leaching poten-
tial of solid waste and has been designated as
ASTM D-3987-85. This test method provides
for the shaking of a water extractant and a
known weight of waste of specified composi-
tion and the separation of the aqueous phase
for analysis. The intent of this test method is
for the final pH of the extract to reflect the
interaction of the extractant with the buffering
capacity of the solid waste.
The shake test is performed by mixing the
solid sample with test water and agitating
continuously for 18±0.25 hours. A liquid-to-
solid ratio of 20:1 by weight is used. After
agitation the solids are filtered from the liquid
extract, and the liquid extract is analyzed.
The water extraction is meant to simulate
conditions where the solid waste is the domi-
nant factor in determining the pH of the
extract. This test, however, has only been
approved for certain inorganic constituents,
and is not applicable to organic substances
2-9
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Getting Started—Characterising Waste
and volatile organic compounds. Copies of
this procedure can be,ordered by calling
ASTM at 610 832-9585 or via the Internet at
.
III. Waste
Characterization
of Volatile
Organic Emissions
To determine whether volatile organic emis-
sions are of concern at a unit, as described in ;
the protecting air chapter, the concentration of
all volatile organics in a waste must be known.
Analytical testing may be necessary if organic
concentrations cannot be estimated using
process knowledge. Many tests have been
developed for quantitatively extracting volatile
and nonvolatile organic compounds from vari-
ous sample matrices, for example extracting all
of the compound present. These tests tend to
be highly dependent upon the physical charac-
teristics of the sample. ^Consult with the state
agency before beginning testing. Refer to SW-
846 Method 3500B for general guidance on
selection of methods for quantitative extraction
or dilution of samples for analysis by one of
the semivolatile or nonvolatile determinative .
methods. After performing the appropriate
extraction procedure, further cleanup of the
sample extract may be necessary if analysis of
the extract is prevented due to interferences
coextracted from the sample. Method 3600 of
SW-846 provides additional guidance on
cleanup procedures. Following preparation of
a sample, the sample is ready for further analy-
sis. Most analytical methods are either gas
chromatography (GC),: high performance liq-
uid chromatography (HPLC), gas chromatog-
raphy/mass spectrometry (GC/MS), or high
performance liquid chromatography/mass
spectrometry (HPLC/MS). SW-846 is designed
to allow the methods to be mixed-and-
matched, so thai sample preparation, sample
cleanup, and analytical methods can be com-
bined into a sequence, as appropriate for the
particular analyte and the matrix. Consult with
the state agency before finalizing the selected
2-10
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Getting Started—Characterizing Waste
Waste Characterization Action Items
a
a
a
a
a
Use process knowledge to identify constituents for further analysis.
Assess the physical state of the waste using process and generator knowledge.
Assess the environment in which the waste will be placed.
Consult with the state agency to determine any state specific testing requirements.
Select an appropriate leachate test or organic constituent analysis based on the above
information.
2-11
-------
Getting Started—Characterizing Waste
Resources
ASTM. 1995. Annual Book of ASTM Standards. Volume 11.04.
California EPA. Handbook for the Analysis and Classification of Wastes.
California EPA. 1995. Preliminary Proposal to Require the TCL? in Lieu of the Waste Extraction
Test. Memorandum to James Carlisle, Department of Toxics Substances Control, from Jon
Marshack, California Regional Water Quality Control Board. December 18.
California EPA. 1994. Regulation Guidance: When Extraction Tests Are Not Necessary.
California EPA. 1994. Regulation Guidance: TCLP vs. WET.
California EPA. 1993. Regulation Guidance: Lab Methods.
California EPA. 1993. Regulation Guidance: Self-classification.
Kendall, Douglas. 1996. Impermanence of Iron Treatment of Lead-Contaminated Foundry Sand—
NIBCO, Inc., Nacogdoches, Texas. National Enforcement Investigations Center Project PA9. April.
Dusing, D.C., Bishop, P.L., and Keener, T.C. 1992. Effect of Redox Potential on Leaching from
Stabilized/Solidified Waste Materials. Journal of Air and Waste Management Association. 42:56.
January.
New Jersey Department of Environmental Protection. 1996. Industrial Pollution Prevention Trends
in New Jersey.
Northwestern University. 1995. Chapter 4—Evaluation of Procedures for Analysis and Disposal of
Lead-Based Paint-Removal Debris. Issues Impacting Bridge Painting: An Overview. Infrastructure
Technology Institute. FHWA/RD/94/098. August.
U.S. EPA. 1998. Guidance on Quality Assurance Project Plans: EPA QA/G-5. EPA600-R-98-018.
U.S. EPA. 1997. Extraction Tests. Draft.
U.S. EPA. 1996. Guidance for the Data Quality Assessment: Practical Methods for Data Analysis:
EPAQA/G-9. EPA600-R-96-084.
2-12
-------
Getting Started—Characterizing Waste
Resources (cont.)
U.S. EPA. 1996. Guidance for the Data Quality Objectives Process: EPA QA/G-4. EPA600-R-96-055.
U.S. EPA. 1996. Hazardous Waste Characteristics Scoping Study.
U.S. EPA. 1996. National Exposure Research Laboratory (NERL)-Las Vegas: Site Characterization
Library, Volume 2.
U.S. EPA. 1996. Test Methods for Evaluating Solid Waste Physical/Chemical Methods—SW846. Third
Edition.
U.S. EPA. 1995. State Requirements for Non-Hazardous Industrial Waste Management Facilities.
U.S. EPA. 1993. Identifying Higher-Risk Wastestreams in the Industrial D Universe: The State
Experience. Draft.
U.S. EPA. 1992. Facility Pollution Prevention Guide. EPA600-R-92-088.
U.S. EPA Science Advisory Board. 1991. Leachability Phenomena: Recommendations and Rationale for
Analysis of Contaminant Release by the Environmental Engineering Committee. EPA-SAB-EEC-92-003.
2-13
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Part I
Getting Started
Chapter 3
Integrating Pollution Prevention, Recycling, and Treatment
-------
Contents
I. Benefits of Pollution Prevention, Recycling, and Treatment 3
II. Implementing Pollution Prevention, Recycling, and Treatment 4
A. Source Reduction 5
B. Recycling 7
C. Treatment 7
111. Where to Find Out More: Technical and Financial Assistance 8
Action Items for Integrating Pollution Prevention, Recycling, and Treatment 11
Resources 12
Figures:
Figure 1: Waste Management Hierarchy 2
-------
Getting Started—Integrating Pollution Prevention, Recycling and Treatment
Integrating Pollution Prevention,
Recycling, and Treatment
Consider pollution prevention, recycling, and treatment options
when designing a waste management system. Pollution preven-
tion and recycling reduce waste disposal needs and can mini-
mize impacts across all environmental media. Treatment can
reduce the volume and/or toxicity of waste. Pollution prevention,
recycling, and treatment can all ease some of the burdens,
risks, and liabilities of waste management.
Pollution prevention, waste
reduction, waste minimization—
these and similar terms describe a
variety of practices that go far
beyond traditional environmental
compliance or single media permits for water,
air, or waste management. This guidance is
designed to help decide how to manage
wastes protectively. Integrating pollution pre-
vention, recycling, and treatment into policies
and operations allows for opportunities to
reduce the volume and toxicity of wastes,
reduce waste disposal needs, and recycle and
reuse materials formerly handled as wastes. In
addition to the potential to save waste man-
This chapter will help address the
following questions:
• What are some of the benefits of pollu-
tion prevention, recycling, and treatment?
• Where can assistance in: choosing and
implementing specific pollution preven-
tion, recycling, and treatment activities
be obtained?
agement costs, pollution prevention, recy-
cling, and treatment may improve the interac-
tions among industry, the public, and regula-
tory agencies; reduce liabilities and risks asso-
ciated with releases from waste management
units; and reduce long-term liabilities and
risks associated with closure and post-closure
care of waste management units.
Pollution prevention is comprehensive and
emphasizes a life-cycle approach to assessing
physical plant, production processes, and
products to identify the best opportunities to
minimize environmental impacts across all
media. This approach also ensures that
actions taken in one area will not increase
environmental problems in another area
(such as reducing wastewater discharges but
increasing airborne emissions of volatile
organic compounds). Pollution prevention
actively involves a broad cross section of
employees in creative problem solving to help
achieve environmental goals and at the same
time benefit a company in many other ways.
For example, redesigning production process-
es or finding alternative materials inputs can
also improve product quality, increase effi-
ciency, and conserve raw materials.
3-1
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
Recycling is similar to pollution prevention
in the sense that both require an examina-
tion of waste streams and production
processes to identify opportunities.
Recycling and beneficially reusing wastes
can help reduce disposal costs, while using;
or reusing recycled materials as substitutes
for feedstocks can reduce raw materials'
costs. Materials exchange programs can
assist in finding uses for recycled materials,
and identifying effective substitutes for raw
materials. Recycling >not only helps reduce :
the overall amount of waste sent for dis-
posal, but also helps conserve natural
resources by replacing the need for virgin
materials.
Treatment can reduce the toxicity of a
waste, its volume, or both. Reducing a
waste's volume and toxicity prior to final
disposal can result in long-term cost sav-
ings. There are a considerable number of
levels and types of treatment from which
to choose. Selecting the right treatment
option can help simplify disposal options
and limit future liability.
i hroughout this guidance some key steps
are highlighted thai are good starting points
for pollution prevention, recycling, or treat-
ment or where pollution prevention, recy-
cling, or treatment could help reduce waste
management costs, increase options, or
reduce potential liabilities by reducing risks
that the wastes might pose. For example:
Waste characterization is a key component
of this guidance. It is also a key compo-
nent of a pollution prevention opportunity
assessment. An opportunity assessment is
more comprehensive, since it also covers
material inputs, production processes,
operating practices, and potentially other
areas such as inventory control. When
characterizing a waste, consider expanding
the assessment to cover these aspects of
the business. An opportunity assessment
can help identify the most efficient, cost
effective, and environmentally friendly
combination of options, especially when
planning new products, new or changed
waste management practices, or facility
expansions.
Figure 1. Waste Management Hierarchy
n
Waste Management Hierarchy
If NO
Disoose
3-2
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
Land application of waste may be a pre-
ferred waste management option because
land application units can manage wastes
with high liquid content, achieve biodegra-
dation, and improve soils with the organic
material in the waste. Concentrations of
constituents may limit the ability to take
full advantage of land application. Reducing
the concentrations of constituents in the
waste before it is generated or treating the
waste prior to land application can provide
the flexibility to use land application and
ensure that the practice will be protective of
human health and the environment and
limit future liabilities.
The Pollution Prevention Act of 1990 estab-
lished a national policy to first, prevent or
reduce waste at the point of generation; sec-
ond, recycle or reuse waste materials; third,
treat waste; and finally, dispose of remaining
waste in an environmentally protective man-
ner (see Figure 1). Some states and many local
governments have adopted similar policies,
often with more specific and measurable goals.
Over the past 10 years, interest in all aspects
of pollution prevention, recycling, and treat-
ment has blossomed, and governments, busi-
nesses, academic and research institutions,
and individual citizens have dedicated greater
resources to it. Many industries are adapting
pollution prevention, recycling, and treatment
practices to fit their individual operations.
Pollution prevention, recycling, and treatment
can be successful when flexible problem-solv-
ing approaches and solutions are implement-
ed. These steps will be successful when they
fit into business and environmental goals.
I. Benefits of
Pollution
Prevention,
Recycling, and
Treatment
Pollution prevention, recycling, and treat-
ment activities benefit industry, states, and the
public by protecting the environment and
reducing health risks, and also provide busi-
nesses with financial and strategic benefits.
Cost savings. Many pollution prevention
activities make
industrial process-
es and equipment
more resource-effi-
cient. This
increased produc-
tion efficiency
saves raw material
and labor costs,
lowers mainte-
nance costs due to
newer equipment,
and lowers over-
sight costs due to
process simplifica-
tion. When planning pollution prevention
activities, consider the cost of the initial invest-
ment for audits, equipment, and labor. This
cost will vary depending on the size and com-
plexity of waste reduction activities. In addi-
tion, consider the payback time for the invest-
ment. Adjust pollution prevention activities to
maximize cost savings and environmental and
health benefits. Lastly, by reducing the volume
and toxicity of waste, treatment activities pro-
vide savings through lower disposal costs.
Simpler design and operating conditions
and reduced regulatory obligations. Reducing
the risks associated with wastes may allow
3-3
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment '
wastes to be managed under less stringent
design and operating conditions or use of
other lower-cost management practices. For
example, the chapter on assessing ground-
water risks may determine that a waste stream
requires a composite liner. The assessment also
might imply that by implementing a pollution
prevention activity that lowered the concentra-
tions of one or two problematic waste con-
stituents in that waste stream, only a compact-
ed clay liner may be necessary. When the risks
associated with waste disposal are reduced, the
long-term costs of closure and post-closure
care may also be reduced.
Improved worker safety.. Processes involving
less toxic and less
physically dangerous
(such as corrosive)
materials can
Improve worker safe-
ty by reducing work-
related injuries and
illnesses. In addition
to strengthening
morale, improved
•worker safety also
reduces health-relat-
ed costs from lost
work days, health
insurance, and disability payments.
Lower liability. A well-operated unit mini-
mizes releases, accidents, and unsafe waste-
handling practices. Reducing the volume and
toxicity of waste decreases the impact of these
events if they occur. Reducing potential liabili-
ties, decreases the likelihood of litigation and
cleanup costs.
Higher product quality. Many corporations
have found that higher product quality results
from some pollution prevention efforts. A sig-
nificant part of waste in some operations con-
sists of products that fail quality inspections,
so minimizing waste in those cases is inextri-
cably linked with process changes that
improve quality. Often, managers do not real-
ize how easy or technically feasible such
changes are until the drive for waste reduction
leads to exploration of the possibilities.
Building community relations. Honesty and
openness can strengthen credibility between
industries, communities and regulatory agen-
cies. If implementing a pollution prevention
program, make people aware of it.
Environmental protection and economic
growth can be compatible objectives.
Additionally, dialogue among all parties in the
development of pollution prevention plans can
help identify and address concerns.
II. Implementing
Pollution
Prevention,
Recycling, and
Treatment
When it comes to pollution prevention,
recycling, and treatment consider a combina-
tion of options that best fits a facility and its
products. There are a number of steps com-
mon to any facility wide pollution prevention,
recycling, and treatment effort. An essential
starting point is to make a clear commitment
3-4
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
to pollution prevention, recycling, and treat-
ment opportunities. Seek the participation of
interested partners, develop a policy state-
ment committing the industrial operation to
pollution prevention, recycling, and treat-
ment, and organize a team to take responsi-
bility for it. As a next step, conduct a thor-
ough pollution prevention opportunity
assessment. Such an assessment will help set
priorities according to which options are the
most promising. Another feature common to
many pollution prevention programs is some
means of measuring the program's progress
and make any necessary adjustments.
The core of a program is the actual pollu-
tion prevention, recycling, and treatment
practices implemented. The following sec-
tions give a brief overview of source reduc-
tion, recycling, and treatment. To find out
more, contact some of the organizations listed
in the appendices to this chapter.
A. Source Reduction
Source reduction is the prevention or min-
imization of waste at the point of generation.
Some examples of source reduction activities
are: input materials modification, technology
modifications, in-process recycling, and vari-
ous good housekeeping measures.
Input materials modification. One option
is to reformulate or
modify products
and processes to
incorporate materi-
als less likely to
produce higher-risk
wastes. Some of the
most common
practices include
eliminating metals
from inks, dyes,
and paints; refor-
mulating paints,
inks, and adhesives to eliminate synthetic
organic solvents; and replacing chemical-
based cleaning solvents with water-based or
citrus-based products. Purchasing raw materi-
als free from even trace quantities of contami-
nants, whenever possible, can also help
reduce waste at the source.
When substituting materials in an industri-
al processes, it is important to examine the
effect on the entire waste stream. Some
changes may shift contaminants to another
medium rather than actually reduce waste
generation. Switching from solvent-based to
water-based cleaners, for example, will
reduce solvent volume and disposal cost, but
is likely to dramatically increase wastewater
volume. Look at the impact of wastewater
generation on effluent limits and wastewater
treatment sludge production.
Technological modifications. Newer
process technologies often include better
waste reduction features than older ones. For
industrial processes that predate considera-
tion of waste and risk reduction, altering
these existing production procedures, adopt-
ing new procedures, or upgrading equipment
may reduce waste volume, toxicity, and man-
agement costs. Some examples include
redesigning equipment to cut losses during
batch changes or during cleaning and mainte-
nance, changing to mechanical cleaning
devices to avoid solvent use, and installing
more energy- and material-efficient equip-
ment. State technical assistance centers, trade
associations, and other organizations listed in
Appendices I through IV can help evaluate
the potential advantages and savings of such
improvements.
In-process recycling (reuse). In-process
recycling reuses materials, such as cutting
scraps, as inputs to the same process from
which they came, or uses them in other
processes or for other uses in the facility. This
furthers waste reduction goals by reducing
3-5
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
the need for treatment or disposal and by
conserving energy and resources. A common
example of in-process recycling is reuse of
wastewater.
Good housekeeping procedures. Some of
the easiest and most cost-effective waste
reduction techniques to implement are sim-
ple improvements in housekeeping. Accidents
and spills generate avoidable disposal hazards
and expenses. They are less likely to occur in
clean, neatly organized facilities.
Good housekeeping techniques that reduce
the likelihood of accidents and spills include
training employees to manage waste and
materials properly; keeping aisles wide and
free of obstructions; clearly labeling contain-
ers with content, handling, storage, expira-
tion, and health and safety information; spac-
ing stored materials to allow easy access; sur-
rounding storage areas with containment
berms to control leaks or spills; and segregat-
ing stored materials to avoid cross-contami-
nation, mixing of incompatible materials, and
unwanted reactions. Proper employee train-
ing is crucial to implementing a successful
waste reduction program, especially one fea-
turing good housekeeping procedures. Case
study data indicate that effective employee
training programs can reduce waste disposal
volumes by 10 to 40 percent.
Regularly scheduled maintenance and plant
inspections are also useful. Maintenance helps
avoid the large cleanups and disposal opera-
tions that can result from equipment failure.
Routine maintenance also ensures that equip-
ment is operating at peak efficiency, saving
energy, time, and materials. Regularly sched-
uled or random unscheduled plant inspections
help identify potential problems before they
cause waste management problems. They also
help identify areas where improving the effi-
ciency of materials management and handling
practices is possible. If possible, plant inspec-
tions occasionally should be performed by
outside inspectors who are less familiar with
day-to-day plant operations. These inspectors
may notice areas for improvement that are
overlooked by employees accustomed to the
plant's routine practices.
Storing large volumes of raw materials
increases the risk of an accidental spill and
the likelihood that the materials will not be
used due to changes in production schedules,
new product formulations, or material degra-
dation. Many companies are forced to dispose
of materials whose expiration dates have
passed or that are no longer needed. Efficient
inventory control allows a facility to avoid
stocking materials in excess of its ability to
use them, thereby decreasing disposal volume
and cost. Furthermore, some companies have
successfully implemented "just-in-time" man-
ufacturing systems to avoid the costs and
risks associated with maintaining a large
onsite inventory. In a "just-in-time" manufac-
turing system, raw materials arrive as they are
needed and only minimal inventories are
maintained on site.
Segregating waste streams is another good
housekeeping procedure that enables a facili-
ty to avoid contaminating lower risk wastes
with hazardous constituents from another
•source. Based on a waste characterization
study, it may be more efficient and cost-effec-
tive to manage wastes separately by recycling
some, and treating or disposing of others.
3-6
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
Waste segregation can also help reduce the
risks associated with handling waste.
Separating waste streams may allow some
materials to be reused, resulting in additional
cost savings. Emerging markets for recovered
industrial waste materials are creating new
economic incentives to segregate waste
streams. Recovered materials are more attrac-
tive to potential buyers if it can be ensured
that they are not tainted with other waste
materials. If wastes from metal-finishing facil-
ities, for example, are segregated by type,
metal specific bearing sludge can be recov-
ered more economically and the segregated
solvents and waste oils can be recycled.
B. Recycling
Recycling involves collecting, processing,
and reusing waste materials. The following
discussion highlights a few of the ways to
begin this process.
Material exchange
programs. Many
regions and states
have established
material exchange
programs to facilitate
transactions between
waste generators and
industries that can use
wastes as raw materials. Material exchanges are
an effective and inexpensive way to find new
users and uses for a waste. Most are publicly
funded, nonprofit organizations, although
some charge a nominal fee to be listed with
them or to access their online databases. Some
actively work to promote exchanges between
generators and users, while others simply pub-
lish lists of generators, materials, and buyers.
Some waste exchanges also sponsor work-
shops and conferences to discuss waste-related
regulations and to exchange information. More
than 60 waste and material exchanges operate
in North America. Contact information for
some of these exchanges is provided in
Appendix III.
Beneficial use. Beneficial use involves sub-
stituting a waste material for another materi-
al with similar properties. Utility companies,
for example, often use coal combustion ash
as a construction material, road base, or soil
stabilizer. The ash replaces other, nonrecy-
cled materials, such as fill or Portland
cement, not only avoiding disposal costs but
also generating revenue. Other examples of
beneficial use include using wastewaters and
sludges as soil amendments (see the chapter
on designing a land application program)
and using foundry sand for asphalt, concrete,
and roadbed construction.
Many regulatory agencies require approval
of planned beneficial use activities and may
require testing of the materials to be reused.
Others may allow certain wastes to be desig-
nated for beneficial use, as long as the
required analyses is completed. Pennsylvania,
for example, allows application of a "coprod-
uct" designation to, and exemption from
waste regulations for, "materials which are
essentially equivalent to and used in place of
an intentionally manufactured product or
produced raw material and... [which present]
no greater risk to the public or the environ-
ment." Generally, regulatory agencies want to
ensure that any beneficially used materials are
free from significantly increased levels of con-
stituents that may pose a greater risk than the
materials they are replacing. Consult with the
state agency for criteria and regulations gov-
erning beneficial use.
C. Treatment
Treating waste helps to reduce its volume
and/or toxicity prior to disposal. Treatment
can also make a waste amenable for reuse or
recycling. The range of treatment methods
from which to choose is as diverse as the
•^Freeman, Harry. 1995. Industrial Pollution Prevention Handbook. McGraw-Hill, Inc. p. 13.
3-7
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
range of wastes to be treated. More advanced
treatment will generally be more expensive,
but, by reducing the quantity and/or risk
level of the waste, costs might be reduced in
the long run. Savings could come from not
only lower disposal costs, but also lower clo-
sure and post-closure care costs. Conversely,
more basic treatment is usually less expensive
but may leave the final waste management
costs higher. Choose the treatment and post-
treatment waste management methods that
will minimize total cost and environmental
impact. Also, be sure to properly manage any
treatment residuals, such as sludges, which
are wastes themselves. The organizations list-
ed in the appendices may be able to assist in
identifying treatment options. '
III. Where to Find
Out More:
Technical
and Financial
Assistance
There is a wealth of information available
to help integrate pollution prevention, recy-
cling, and treatment into an operation. As a
starting point, lists of technical and financial
resources that identify some of the main
places to turn to for assistance are included in
the appendices. Use the Internet as a source
of background information on the various
resources to help narrow the search for assis-
tance. Eventually, a network of contacts to
support all the various technical needs can be
built. Waste reduction information and tech-
nologies are constantly changing. To follow
new developments, maintain technical and
financial contacts and use the resources even
after beginning waste reduction activities.
Where can assistance be
obtained?
Several types of organizations offer assis-
tance. These include offices in regulatory
agencies, university departments, nonprofit
foundations, and trade associations.
Additionally, the National Institute of
Standards and Technology (NIST)
Manufacturing Extension Partnerships
(MEPs) also provide waste reduction informa-
tion. Look for waste reduction staff within the
media programs (air, water, solid/hazardous
waste) of regulatory agencies or in the state
commissioner's office, special projects divi-
sion, or pollution prevention division. Some
states also provide technical assistance for
waste reduction activities, such as recycling,
through a business advocate or small business
technical assistance program.
The listings in the accompanying appen-
dices identify some primary sources for tech-
nical assistance but are far from exhaustive.
There are many additional organizations that
offer waste reduction/pollution prevention
assistance on regional, state, and local levels.
Some of the organizations listed by state may
be able to help contact these other organiza-
tions. To help locate the organizations in a
state or those most relevant to an industry,
the listings are divided into four appendices.
Once started, the list of potential contacts can
be quickly expand.
3-8
-------
Getting Started—Integrating Pollution Prevention, Recycling and Treatment
• Appendix I: State Technical
Assistance Organizations. Regulatory
and nonregulatory organizations
offering various forms of technical
assistance within each state.
• Appendix II: Trade Associations.
Trade associations that can give
more industry- or material-specific
technical assistance resources.
• Appendix III: North American
Material Exchange Programs. A
sampling of material exchange pro-
grams across North America.
• Appendix IV: Publications, Online
Resources, and Software. An
overview of places to find general
information about waste reduction
options.
As contact information inevitably changes
with time, check the local telephone listings
or investigate online resources, such as The
National Pollution Prevention Roundtable's
directory, The Pollution Prevention Yellow Pages
, if trying to
contact an organization that is no longer
available at the number listed.
What types of technical
assistance are available?
Many state and local governments have
technical assistance programs that are sepa-
rate from regulatory offices. In addition, non-
governmental organizations implement a
wide range of activities to educate businesses
about the value of waste reduction. These
efforts range from providing onsite technical
assistance and sharing industry-specific expe-
riences to conducting research and develop-
ing education and outreach materials on
waste reduction topics. The following exam-
ples illustrate what services are available:
• NIST technical centers. There are
NIST-sponsored Manufacturing
Technology Centers throughout the
country as part of the grassroots
Manufacturing Extension
Partnership (MEP) program. The
MEP program helps small and
medium-sized companies adopt new
waste reduction technologies by pro-
viding technical information, financ-
ing, training, and other services. The
NIST web site
offers a page that can help find the
nearest center.
• Trade associations. Trade associa-
tions provide industry-specific
assistance through publications,
workshops, field research, and
consulting services.
• Onsite technical assistance audits.
These audits are for small (and
sometimes larger) businesses. The
assessments, which take place out-
side of the regulatory environment
and on a strictly voluntary basis,
provide businesses with information
on how to save money, increase
efficiency, and improve community
relations.
• Information clearinghouses. Many
organizations maintain repositories
of waste reduction information and
serve as starting points to help
businesses access this information.
• Facility planning assistance. A num-
ber of organizations can help
businesses develop, review, or evalu-
ate facility waste reduction plans.
State waste reduction programs frequently
prepare model plans can implement to mini-
mize waste.
3-9
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment \
Research and collaborative projects.
Academic institutions, state agencies and
other organizations frequently participate
in research and collaborative projects
with industry to foster development of
waste reduction technologies and man-
agement strategies. Laboratory and
field research activities include studies, ;
surveys, database development, data
collection, and analysis.
Hotlines. Some states operate tele-
phone assistance services to provide
technical waste reduction informa-
tion to industry and the general
public. Hotline staff typically answer
questions, provide referrals, and :
distribute printed technical materials
on request.
Computer searches and the Internet.
The Internet brings many
pollution prevention resources to a
users fingertips. The wide range of
resources available electronically can
provide information about inno-
vative waste-reducing technologies,
efficient industrial processes, current
state and federal regulations, and
many other pertinent topics.
Independent, searches can be done
on the Internet, and some states
perform computer searches to pro-
vide industry with information
about waste reduction. EPA and
many state agencies have web sites
dedicated to these topics, with case
studies, technical explanations,
legal information, and links to other
sites for more information.
Workshops, seminars, and training. State
agencies, trade associations, and other
organizations conduct workshops, semi-
nars, and technical training on waste
reduction. These events provide informa-
tion, identify resources, and facilitate net
working.
Grants and loans. A number of
states distribute funds to indepen-
dent groups that conduct waste
reduction activities. These groups
often use such support to fund
research and to run demonstration
and pilot projects.
3-10
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Getting Started—Integrating Pollution Prevention, Recycling and Treatment
a
D
a
a
a
a
a
Action Items for Integrating Pollution
Prevention, Recycling, and Treatment
Make waste management decisions by considering the priorities full range of
options—first, source reduction; second, reuse and recycling; third, treatment; last,
disposal.
Explore the cost savings and other benefits available through activities that integrate
pollution prevention, recycling, and treatment.
Develop a waste reduction policy.
Conduct a pollution prevention opportunity assessment of facility processes.
Research potential pollution prevention, recycling, and treatment activities.
Consult with public and private agencies and organizations providing technical and
financial assistance for pollution prevention, recycling, and treatment activities.
Plan and implement activities that integrate pollution prevention, recycling, and
treatment.
3-11
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Getting Slatted—Integrating Pollution Prevention, Recycling and Treatment
Resources
Freeman, Harry. 1995. Industrial pollution prevention handbook. McGraw-Hill, Inc.
"Green consumerism: Commitment remains strong despite economic pessimism." 1992. Cambridge
Reports. Research International. (October).
Habicht, E Henry. 1992. U.S. EPA memorandum on EPA definition of pollution prevention (May).
Higgins, Thomas E., ed. 1995. Pollution prevention handbook. CRC-Lewis Publishers.
"Moving from industrial waste to coproducts." 1997. Biocycle. (January)
National Pollution Prevention Roundtable. 1995. The Pollution Prevention Yellow Pages.
Rossiter, Alan P., ed. 1995. Waste minimization through process design. McGraw-Hill, Inc.
U.S. EPA. 1997. Technical support document for best management practices programs—spent
pulping liquor management, spill prevention, and control.
U.S. EPA. 1994. Final best demonstrated available technology (BDAT) background document for
universal standards, Volume B: Universal standards for wastewater forms of listed hazardous wastes,
Section 5, Treatment performance database. EPA530-R-95-033.
U.S. EPA. 1993. Guidance manual for developing best management practices.
EPA833-B-93-004. ;
U.S. EPA. 1992. Facility pollution prevention guide. EPA600-R-92-008.
U.S. EPA. 1991. Pollution prevention strategy. EPA741-R-92-001.
U.S. EPA. 1988. Waste minimization opportunity assessment manual.
EPA625-7-88-003.
U.S. Army Corps of Engineers, 1984. Engineering and design: Use of geotextiles under riprap. ETL
1110-2-286.
U.S. EPA. 1995. Decision-maker's guide to solid waste management, 2nd ed. EPA530-R-95-023.
l!
U.S. EPA. 1995. OSWER environmental justice action agenda. EPA540-R-95-023.
U.S. EPA. 1995. RCRA Subtitle D (258) Seismic design guidance for municipal solid waste landfill
facilities. EPA600-R-95-051.
3-12
-------
Getting Started—Integrating Pollution Prevention, Recycling and Treatment
Resources (cent.)
U.S. EPA. 1995. Why do wellhead protection? Issues and answers in protecting public drinking water
supply systems. EPA813-K-95-001.
U.S. EPA. 1994. Design, operation, and closure of municipal solid waste landfills.
EPA625-R-94-008.
U. S. EPA. 1994. Handbook: Ground water and wellhead protection.
EPA625-R-94-001.
3-13
-------
-------
Part I
Getting Started
Chapter 4
Considering the Site
-------
Contents
I. General Site Considerations ....; 2
A. Hoodplains 2
B. Wetlands 5
C. Active Fault Areas 9
D. Seismic Impact Zones , 10
E. Unstable Areas , 14
F. Airport Vicinities 17
G. Wellhead Protection Areas 18
II. Buffer Zone Considerations 19
A. Recommended Buffer Zones 20
B. Additional Buffer Zones , 21
III. Local Land Use and Zoning Considerations 22
IV. Environmental Justice Considerations 22
Considering the Site Action Items 24
Resources 26
Tables:
Table 1: Examples of Improvement Techniques for Liquefiable Soil Foundation Conditions 11
-------
Getting Started—Considering the Site
Considering the Site
Become familiar with environmental, geological, and manmade fea-
tures that influence siting decisions. Identify nearby areas or land
uses that merit buffer zones, and place the unit an appropriate dis-
tance from them. Comply with land use and zoning restrictions.
Understand existing environmental justice issues when considering
a new site. Avoid siting units in problem areas, or design units to
address conditions in those areas.
Many hydrologic and geologic
settings can be effectively uti-
lized for protective waste
management. There are,
however, some hydrologic
and geologic conditions that are best avoided
all together if possible. If they cannot be
avoided, special design and construction pre-
cautions can minimize risks. Floodplains,
earthquake zones, unstable soils, and areas at
risk for subsurface movement need to be
taken into account just as they would be in
This chapter will help address the
Mowing questions:
* What types of sites need special
consideration?
- How is it determined if a unit is in an
area requiring special consideration?
* What issues are associated with siting a.;
. waste management unit insuch areas?
* What actions can; be taken if a unit is
planned to these areas?. • y
siting and constructing a manufacturing plant
or home. Catastrophic events associated with
these locations could seriously damage or
destroy a unit, release contaminants into the
environment, and add substantial expenses
for cleanup, repair or reconstruction. If prob-
lematic site conditions cannot be avoided,
engineering design and construction tech-
niques can address some of the concerns
raised by these locations.
Many state, local, and tribal governments
require buffer zones between waste manage-
ment units and other nearby land uses. Even
if buffer zones are not required, they can still
provide benefits now and in the future. Buffer
zones provide time and space to contain and
remedy accidental releases before they reach
sensitive environments or sensitive popula-
tions. Buffer zones also help maintain good
community relations by reducing disruptions
associated with noise, traffic, and wind-blown
dust, often the source of serious neighbor-
hood concerns.
In considering impacts on the surrounding
community, it is important to understand
whether the community, especially those with
large minority and low income populations,
4-1
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Getting Started—Considering the Site
already face significant environmental impacts
from existing industrial activities. Understand a
community's current environmental problems
and work together to develop plans that can
improve and benefit the environment, the com-
munity, the state, and the company.
How should a unit site
assessment begin?
In considering whether to laterally expand a
unit or site a new unit, certain factors influence
prospective sites. These factors include land
availability, distance from waste generation
points, ease of access, local climatic conditions,
economics, environmental considerations, local
zoning requirements, and community impacts.
As prospective sites are identified, become
familiar with the siting concerns raised in this
chapter, and determine how to address them at
each site to minimize a unit's adverse impacts
on the environment and the environment's
adverse impacts on the unit. Choose the site
that best balances efficient protection of human
health and the environment with meeting oper-
ational goals. In addition to issues raised in diis
chapter, check widi state and local regulatory
agencies early in the siting process to identify
applicable restrictions.
I. General Siting
Considerations
Examining the topography of a site is die first
step in siting a unit. To obtain topographic infor-
mation, contact the U.S. Geological Survey
(USGS), the Natural Resources Conservation
Service (NRCS)1, the state's geological survey or
agency (see Appendix I), or local colleges and
universities. Remote sensing data or maps from
these organizations can help determine whether a
prospective site is located in any of the areas of
concern discussed in this section. USGS maps
can be downloaded and ordered from their web
page at . The University of
Missouri-Rolla maintains a current list of State
Geological Surveys on their web page at
.
A. Floodpiains
A floodplain is a relatively flat, lowland area
adjoining inland and coastal waters. The 100-
year floodplain—the area susceptible to inun-
dation during a large magnitude flood with a
1 percent chance of recurring in any given
year—is usually the floodplain of concern for
waste management units. Determine whether
a candidate site is in a 100-year floodplain.
Siting a unit in a 100-year floodplain increases
the likelihood of floods inundating a surface
impoundment or land application unit,
increases the potential to damage liner and
support components of a landfill or waste
pile, and presents operational concerns. This,
in turn, creates environmental and human
health and safety concerns, as well as legal lia-
bilities. It also can be very costly to build a
unit to withstand a 100-year flood without
washout of waste or damage to the unit, or to
reconstruct a unit after such a flood. Further,
Flood waters overflowed from the
Mississippi River (center) into its floodplain
(foreground) at Quincy, Illinois in the 1993
floods that exceeded 100-year levels in some
parts of the Midwest.
•'•This agency of the U.S. Department of Agriculture was formerly known as the Soil Conservation Service (SCS).
4-2
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Getting Started—Considering the Site
FEMA provides flood maps like this one for most floodplains
Source: FEMA, Q3 Flood Data Users Guide .
locating a unit in a floodplain may exacerbate
the damaging effects of a flood, both
upstream and downstream, by reducing the
temporary water storage capacity of the
floodplain. As such, potential sites located
outside the 100-year floodplain are preferable
How is it determined if a
prospective site is in a 100-year
floodplain?
The first step in determining whether a
prospective site is
located in a 100-
year floodplain is to
consult with the
Federal Emergency
Management
Agency (FEMA).
FEMA has prepared
temporary flood
hazard boundary
maps for most
regions. If a
prospective site
does not appear to
be located in a
floodplain, future
exploration is not
necessary. If uncer-
tainty exists as to
whether the
prospective site may
be in a floodplain,
several sources of
information are
available to help
make this determi-
nation. More
detailed flood insur-
ance rate maps
(FIRMs) can be
obtained from
FEMA that classify
areas into three classes: A, B, and C. Class A
zones are the most susceptible to flooding
while Class C zones are the least susceptible.
FIRMs may be obtained from FEMA's web
page at .
Additional information can be found on
flood insurance rate maps in FEMA's publica-
tion How to Read a Flood Insurance Rate Map
(see ).
FEMA also publishes The National Flood
Insurance Program Community Status Book,
which lists communities with flood insurance
rate maps or floodway maps. Floodplain maps
4-3
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Getting Started—Considering the Site
can also be obtained through the U.S. Army
Corps of Engineers (COE); USGS; NRCS; the
Bureau of Land Management; the Tennessee
Valley Authority; and state, local, and tribal .
agencies.2
Note that river channels shown in flood-
plain maps may have changed due to
hydropower or flood control projects. As a
result, some floodplain boundaries may be
inaccurate. If this is suspected to be the case,
consult recent aerial photographs to determine
how river channels have been modified.
If maps can not be located, and a potential
site is suspected to be located in a floodplain,
conduct a field study to delineate the floodplain
and determine die floodplain's properties. A
delineation can draw on meteorological records
and physiographic information, such as existing
and planned watershed land use, topography,
soils and geographic mapping, and aerial photo-
graphic interpretation of land forms.
Additionally, use the U.S. Water Resource
Council's methods of determining flood poten-
tial based on stream gauge records, or estimate
the peak discharge to approximate the probabili-
ty of exceeding die 100-year flood.
What can be done if a prospec-
tive site is in a floodplain?
If siting a waste management unit in a flood-
plain, design die unit to prevent the washout
of waste, avoid significant alteration of flood
flow, and maintain die temporary storage
capacity of the floodplain. Use engineering
models to estimate a floodplain's storage
capacity and floodwater flow velocity. The
COE Hydrologic Engineering Center has
developed several computer models for simu-
lating flood properties.3 The models can
account for a waste management unit placed
in a floodplain and can also simulate flood
control structures and sediment transport. If a
computer model calculates that placement of
the waste management unit in the floodplain
raises the base flood level by more than 1 foot,
the unit may alter the storage capacity of the
floodplain. If designing a new unit, site it to
minimize these effects. The impact of a unit's
location on the speed and flow of flood waters
determines die likelihood of waste washout.
To quantify this, estimate the shear stress on
the unit's components caused by the imping-
ing flood waters at the depth, velocity, and
duration associated with the peak, or highest,
flow period of the flood.
Several available options can protect a waste
management unit from flood damage and
washout.
• Design embankments using materi-
als such as riprap—rock cover used
Knowing the behavior of waters at their
peak flood level is important for determin-
ing whether waste will wash out.
^Copies of flood maps from FEMA are available at Map Service Center, P.O. Box 1038, Jessup, MD
20794-1038, or by phone 800 358-9616 or the Internet at .
4-4
HEC-1, HEC-2, HEC-5, and HEC-6 software packages are available free of charge through the COE
World Wide Web site, .
-------
Getting Started—Considering the Site
to protect soil in dikes or channels
from erosion—and/or geotextiles to
minimize erosion.
• Construct dikes to serve as barrier
walls to protect the disposal area.
This is especially important in the
case of surface impoundments.
• Consider erosion control methods,
such as gabions—structures formed
from crushed rock encased in wire
mesh—or paving bricks and mats
constructed of natural or geosyn-
thetic materials. These materials can
provide erosion protection and allow
for vegetative growth.
While these methods may help protect a
unit from flood damage and washout, be
aware that they may further contribute to
decreasing the water storage and flow capaci-
ty of the floodplain. This, in turn, may raise
the level of flood waters not only in the area
but in upstream and downstream locations,
increasing the danger of flood damage and
adding to the cost of flood control programs.
Thus, serious consideration should be given
to not siting a waste management unit in a
100-year floodplain.
B. Wetlands
Wetlands, which include swamps, marshes,
and bogs, are vital and delicate ecosystems.
They are among the most productive biological
communities on earth and provide habitat for
many plants and animals, including approxi-
mately 45 percent of all endangered or threat-
ened species. Wetlands protect water quality by
assimilating water pollutants, removing sedi-
ments containing heavy metals, and recharging
ground-water supplies. Wetlands also prevent
potentially extensive and costly floods by tem-
porarily storing flood waters and reducing their
velocity. These areas also offer numerous recre-
ational opportunities.
Potential adverse impacts associated widi
locating a unit in a wetland include dewatering
the wetland, contaminating the wetland, and
causing loss of wetland acreage. Damage also
could be done to important wetland ecosys-
tems by destroying their aesthetic qualities and
diminishing wildlife breeding and feeding
opportunities. Siting in a wetland also increases
the potential for damage to a unit, especially
the liner system and structural components, as
a result of ground settlement, action of the high
water table, and flooding. Alternatives to siting
a waste management unit in a wedand should
be given serious consideration based upon
Section 404 requirements in the Clean Water
Act (CWA) discussed below.
If a unit is to be sited in a wedand, die
unit will be subject to additional regulations.
In particular, CWA Section 404 authorizes
the Secretary of the Army, acting through the
Chief of Engineers (COE), to issue permits
for the discharge of dredged or fill material
into wetlands and other waters of the United
States.4 Activities in waters of the United
States regulated under this program include
fills for development, water resource projects,
infrastructure improvements, and conversion
of wetlands to uplands for farming and
forestry. Section 404 stipulates that no
discharge of dredged or fill material can be
For regulatory^pufposes under the
Water Act,swetlattds are defined as areas'
"that are inundg:ed^or saturated,by,sur- „
face or ground water at a frequency arid'%
duration, sufficient to support^andjthat
under normal orcumstances'do 'support,
a prevalence of vegetation- typically adapt-
ed for life in saturated" sofl conditions." '
/ y *• S~~
;40 Code of Federal Regulations
(CFR)232.2(r)~ * , -
33 United States Code 1344.
4-5
-------
Getting Started—Considering the Site
Riprap reduces stream channel erosion (left) and gabions help stabilize erodible slopes
(right).
Sources: U.S. Department of the Interior, Office of Surface Mining (left); The Construction Site—A Directory To
The Construction Industry, (right).
permitted if a practicable alternative exists
that is less damaging to the aquatic environ-
ment or if the nation's waters would be sig-
nificantly degraded. Therefore, in compliance
with the guidelines established under Section
404, all permit applicants must:
• Take steps to avoid wedand impacts
where practicable;
• Minimize impacts to wetlands where
they are unavoidable; and
• Compensate (offset) for any remaining,
unavoidable impacts by restoring
existing wetlands;or creating new wet-
lands.
EPA and COE joindy administer a review
process to issue permits for regulated activities.
For projects with potentially significant
impacts, an individual permit is usually
required. For most discharges with only mini-
mal adverse effects, COE may allow applicants
to comply with existing general permits, which
are issued on a nationwide, regional, or
statewide basis for particular activity categories
as a means to expedite the permitting process.
In making permitting decisions, the agencies
will consider numerous other federal laws that
may restrict placement of waste management
units in wetlands. These include the
Endangered Species Act, die Migratory Bird
Conservation Act, the Coastal Zone
Management Act, the Wild and Scenic Rivers
Act, the Marine Protection, Research and
Sanctuaries Act, and the National Historic
Preservation Act.
How is it known if a prospective
site is in a wetland?
As a first step, determine if the prospec-
tive site meets the definition of a wetland. If
the prospective site does not appear to be a
wetland then no further exploration is neces-
sary. If it is uncertain whether the prospective
site is a wetland, then several sources are
available to help make this determination and
define the boundaries of the wetland.
Although this can be a challenging process, it
will help avoid future liability since filling a
wetland without the appropriate federal, state,
or local permit is a violation of the law. It may
be possible to leam the extent of wetlands
4-6
-------
Getting Started"—Considering the Site
Spruce bog (left) and Eco Pond in the Florida Everglades (right): different types of wetlands.
without performing a new delineation, since
many wetlands have previously been mapped.
The first step, therefore, should be to deter-
mine whether wetland information is available
for the area. At the federal level, four agencies
are principally involved with wetlands identi-
fication and delineation: COE, EPA, the U.S.
Fish and Wildlife Service (FWS), and NRCS.
EPA also has a Wetlands Protection Hotline
(800 832-7828) and a wetlands web page at
which pro-
vides information about EPA's wetlands pro-
gram; facts about wetlands; the laws, regula-
tions, and guidance affecting wetlands; and
science, education, and information resources
for wetlands. The local offices of NRCS (in
agricultural areas) or COE (see Appendix II
for contact information) may know whether
wetlands in the vicinity of the potential site
have already been delineated. Additionally,
FWS maintains the National Wetlands
Inventory (NWI) Program5, from which wet-
lands mapping for much of the United States
is obtainable. This mapping, however, is
based on aerial photography, which is not reli-
able for specific field determinations. If a site
has recently been purchased, the previous
property owner may know whether any delin-
eation has been completed that may not be on
file with these agencies. Even if existing delin-
eation information for the site is found, it still
may be prudent to contact a qualified wet-
lands consultant to verify the wetland bound-
aries, especially if the delineation is not a field
determination or is more than a few years old.
If the existence of a wetland is uncertain,
obtain a wetlands delineation. This procedure
should be performed only by a qualified pro-
fessional wedands delineator6 using standard
federal delineation procedures or applicable
state or local delineation standards. The delin-
eation procedure, with which to become famil-
iar with before hiring a delineator, involves col-
lecting maps, aerial photographs, plant data,
soil surveys, stream gauge data, land use data,
and other information. Delineation for Section
404 permitting purposes should be conducted
in accordance with the 1987 U.S. Army Corps
of Engineers Wetlands Delineation Manual.7
(HQUACE, 27 Aug. 91). The manual provides
guidelines and methods to determine whether
an area is a wetland for purposes of Section
5To contact NWI, write to National Wetlands Inventory, 9720 Executive Center Drive, Suite 101, Monroe
Building, St. Petersburg, FL 33702; or call 813 570-5412; or fax 813 570-5420. For additional informa-
tion online or to search for maps of an area, connect to .
6In March 1995, COE proposed standards for a Wetlands Delineator Certification Program (WDCP).
Until these standards are finalized, there is no federal certification program. Once the WDCP standards
are implemented, use WDCP-certified wetland consultants.
^The 1987 manual can be obtained from NTIS (see References section below) or online at
.
4-7
-------
Getting Started^-Considering the Site
Wetland Resource Map
Tampa Bay, Florida
• JtoiK rad EttMriM DKprate Hah&fe
Q Beepnater Ltlw aid Stan
• ErtuBK R&nfes aid Aqratic Bede
Slimline Fire fed Weflmdi
HajdMrolw nti Aqtalic Beds
felalrhe Snl&rib
— H&jor Road*
NWI wetland resource maps like this one show the locations of various different types of wet-
lands and are available for many areas.
Source: NWI web site, sample GIS Think Tank maps page, .
404. The manual outlines a three-parameter
approach that determines the presence and
location of hydrophytic vegetation, wetland
hydrology, and hydric soils.
What can be done if a prospec-
tive site is in a wetland?
Before building a waste management unit
in a wetland area, consider whether the unit
can be located elsewhere. If an alternative
location can be identified, strongly consider
pursuing such an option. Section 404 of the
CWA requires this. As wetlands are important
ecosystems that should be protected, identify-
ing practicable alternatives to locating a unit
in a wetland area is a necessary step in the
siting process. Even if no viable alternative
locations are identified, it may be beneficial
to keep a record of investigated alternatives,
noting why they were not acceptable. Such
records may be useful during the interaction
between industries, states, and members of
the community.
If no alternatives are available, consult
with state and local governments about wet-
land permits. Most states operate permitting
programs under the CWA, and state authori-
ties can help navigate the permitting process.
To obtain a permit, the state might require an
operator to assess wetland impacts and then:
• Prevent contamination from leachate
and run-off;
• Minimize dewatering effects;
4-8
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Getting Started—Considering the Site
• Compensate the loss of wetland
acreage by creating new wetlands or
restoring existing ones; and
• Protect the waste management unit
against settling.
C. Active Fault Areas
Faults occur when stresses in a geologic
material exceed its ability to withstand them.
Areas surrounding faults are subject to earth-
quakes and ground failures, such as landslides
or soil liquefaction. Fault movement may
weaken or destroy structures directly, or seis-
mic activity associated with faulting may cause
damage to structures dirough vibrations. Any
damage to the waste management unit could
result in the release of contaminants. In addi-
tion, fault movement might create avenues to
ground-water supplies, increasing the risk of
ground-water contamination.
Liquefaction is another common problem
encountered in areas of seismic activity. The
vibrating motions caused by an earthquake
tend to rearrange the sand grains in soils. If the
grains are saturated, the saturated granular
material turns into a viscous fluid, a process
referred to as liquefaction. This diminishes the
bearing capacity of the soils and may lead to
foundation and slope failures.
To avoid these hazards, do not build or
expand a unit within 200 feet of an active
fault. If it is not possible to site a unit more
than 200 feet from an active fault, design the
unit to withstand the potential ground move-
ment associated with the fault area. A fault is
considered active if there has been movement
along the fault within the last 10,000 to
12,000 years.
How is it known if a prospective
site is in a fault area?
A series of USGS maps, Preliminary Young
Fault Maps, Miscellaneous Field Investigation
916, identifies active faults.8 These maps may
not be completely accurate due to recent
shifts in fault lines. If a prospective site is well
outside the 200 foot area of concern, no fault
area considerations would exist. If it is
unclear how close a prospective site is to an
active fault, more evaluation will be neces-
sary. A geologic reconnaissance of the site
and surrounding areas may be useful in veri-
fying that the site is free of active faults.
If a prospective site is in an area known
or suspected to be prone to faulting, conduct
a fault characterization to determine if the site
is near a fault. A characterization includes
identifying linear features that suggest the
presence of faults within a 3,000-foot radius
of the site. Such features might be shown or
described on maps, aerial photographs,9 logs,
reports, scientific literature, or insurance
claim reports, or identified by a detailed field
reconnaissance of the area.
If the characterization study reveals faults
within 3,000 feet of the proposed unit, con-
duct further investigation to determine
whether any of the faults are active within
200 feet of the unit. This investigation may
involve drilling and trenching the subsurface
to locate fault zones and evidence of faulting.
Use perpendicular trenching on any fault
within 200 feet of the proposed unit to exam-
ine the seismic epicenter for indications of
recent movement.
Information about ordering these maps is available by calling 800 USA-MAPS or 303 236-7477.
9The National Aerial Photographic Program and the National High Altitude Program, both administered
by USGS, are good national sources of aerial photographs for prospective sites. To order from USGS, call
605 594-6151. For more information, visit . Local aerial
photography firms and surveyors are also good sources.
4-9
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Getting Started—Considering the Site
What can be done if a prospec-
tive site is in a fault area?
If an active fault exists on the site where
the unit is planned, consider placing the unit
200 feet back from the fault area. Even with
such setbacks, only place a unit in a fault area
if it is possible to ensure that no damage to
the unit's structural integrity would result. A
setback of less than 200 feet might be ade-
quate if ground movement would not damage
the unit.
If a lateral expansion or a new unit will
be located in an area susceptible to seismic
activity, there are two issues to consider: hori-
zontal accelerations and movements affecting
side slopes. Horizontal acceleration becomes
a concern when a location analysis reveals
that the site is in a zone of increased risk of
horizontal acceleration in the range of 0.1 g
to 0.75 g (g = acceleration of gravity). In
these zones, the unit design should incorpo-
rate measures to protect the unit from poten-
tial ground shifts. To address side slope con-
cerns, conduct a seismic stability analysis to
determine the most effective materials and
gradients for protecting the unit's slopes from
any seismic instabilities. Further, design the
unit to withstand the impact of vertical accel-
erations.
If an investigation reveals that a unit is in
an area susceptible to liquefaction, consider
ground improvement measures. These mea-
sures include grouting, dewatering, heavy
tamping, and/or excavation. See Table 1 for
examples of currently available techniques.
Further engineering options for fault
areas include the use of flexible pipes for run-
off and leachate collection and redundant
containment systems. In the event of founda-
tion soil collapse or heavy shifting, flexible
run-off and leachate collection pipes—along
In this aerial view, the best-known fault in the
U.S., the San Andreas, slices through the
Carrizo Plain east of San Luis Obispo, California.
Source: USGS
with a bedding of gravel or permeable materi-
al—can absorb some of the shifting-related
stress to which the pipes may be subjected.
Consider also a secondary containment mea-
sure, such as an additional liner system. In
earthquake-like conditions, a redundancy of
this nature may be necessary to prevent cont-
amination of the surrounding area if the pri-
mary liner system fails.
D. Seismic Impact Zones
A seismic impact zone is an area having a
10 percent or greater probability that the
maximum horizontal acceleration caused by
an earthquake at the site will exceed 0.1 g in
250 years. This seismic activity may damage
4-10
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Getting Started—Considering the Site
Table 1
Examples of Improvement Techniques for Liquefiable Soil Foundation Conditions
Method Principle Most Suitable Soil Applications 1
Conditions/Types 1
Blasting
Vibrocompaction
Compaction
piles
Displacement and
compaction grout
Mix-in-place
piles and walls
Heavy tamping
(dynamic
compaction)
Shock waves and vibrations
cause limited liquefaction,
displacement, remolding, and
settlement to higher density.
Densification by vibration and
compaction of backfill material
of sand or gravel.
Densification by displacement of
pile volume and by vibration
during driving, increase in lateral
effective earth pressure.
Highly viscous grout acts as radial
hydraulic jack when pumped in
under high pressure.
Lime, cement, or asphalt intro-
duced through rotating auger or
special in-place mixer.
Repeated application of high
-intensity impacts at surface.
Saturated, clean sands;
partly saturated sands
and silts after flooding.
Cohesionless soils with
less than 20 percent fines.
Loose sandy soils; partly
saturated clayey soils;
loess.
All soils.
Sand, silts, clays, all soft or
loose inorganic soils.
Cohesionless soils best,
other types can also be
improved.
Induce liquefaction in controlled
and limited stages and increase
relative density to potentially
nonliquefiable range.
Induce liquefaction in controlled
and limited stages and increase
relative densities to nonliquefi-
able condition. The dense col-
umn of backfill provides (a) vert-
ical support, (b) drainage to
relieve pore water pressure, and
(c) shear resistance in horizontal
and inclined directions. Used to
stabilize slopes and strengthen
potential failure surfaces.
Useful in soils widi fines. Increases
relative densities to nonliquefiable
range. Provides shear resistance in
horizontal and inclined directions.
Useful to stabilize slopes and
strengthen potential failure surfaces.
Increase in soil relative density and
horizontal effective stress. Reduce
liquefaction potential. Stabilize the
ground against movement.
Slope stabilization by providing shear
resistance in horizontal and inclined
directions, which strengthens poten-
tial failure surfaces or slip circles. A
•wall could be used to confine an area
of liquefiable soil.
Suitable for some soils with fines;
usable above and below water. In
Cohesionless soils, induces liquefac-
tion in controlled and limited stages
and increases relative density to
potentially nonliquefiable range.
Source: RCRA Subtitle D (258) Seismic Design Guidance for Municipal Solid Waste Landfill Facilities. EPA600-R-95-051
4-11
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Getting Started—Considering the Site
leachate collection, detection, and removal
systems or other unit structures through
excessive bending, shearing, tension, and/or
compression. If a unit's components fail,
leachate may contaminate surrounding areas.
For safety reasons, therefore, it is recommend
that a unit not be located in a seismic impact
zone. If a unit must be sited in a seismic
impact zone, the unit should be designed to
withstand earthquake-related hazards, such
as landslides, slope failures, soil compaction,
ground subsidence, and soil liquefaction.
Additionally, if a unit is built in a seismic
impact zone, avoid rock and soil types that are
especially vulnerable to earthquake shocks.
These include very steep slopes of weak, frac-
tured, and brittle rock or unsaturated loess,
which are vulnerable to transient shocks
caused by tensional faulting. Avoid loess and
saturated sand as well, because seismic shocks
can liquefy them, causing sudden collapse of
structures. Similar effects are possible in sensi-
tive cohesive soils when natural moisture
exceeds the soil's liquid limit. (See the "Soil
Properties" section in ;the chapter on designing
and installing liners for a discussion of liquid
limits.) Earthquake-induced ground vibrations
can also compact loose granular soils. This
could result in large uniform or differential set-
dements of the ground surface.
How is it known if a prospective
site is in a seismic impact zone?
If a prospective site is in an area with no
history of earthquakes, then seismic impact
zone considerations may be unnecessary. If it
is unclear whether the area has a history of
seismic activity, then further evaluation will
be necessary. As a first step, consult the USGS
field study map series MF-2120, Probabilistic
Earthquake Acceleration and Velocity Maps for
the United States and Puerto Rico.10 It provides
state- and county-specific information about
seismic impact zones. Additional information
is available from the USGS National
Earthquake Information Center (NEIC),11
which maintains a database of known earth-
quake and fault zones.
If a site is or may be in a seismic impact
zone, it also is useful to analyze the effects of
seismic activity on soils in and under a unit.
Computer software programs are available
that can evaluate soil liquefaction potential.
Liquefaction is the process by which soils
change from solid to liquid state due to
repeated shearing during or following an
earthquake. LIQUFAC, a software program
developed by the Naval Facilities Engineering
Command in Washington, DC, can calculate
safety factors for each soil layer in a given soil
profile and the corresponding one dimension-
al settlements due to earthquake loading.
What can be done if a prospective
site is in a seismic impact zone?
If a waste management unit cannot be
sited outside a seismic impact zone, structural
components of the unit—including liners,
leachate collection systems, and surface-water
control systems—should be designed to resist
the earthquake-related stresses expected in the
local soil. Consult professionals experienced
in seismic analysis and design to ensure that
the unit is designed appropriately. To deter-
mine the potential effects of seismic activity
on a structure, the seismic design specialist
should evaluate soil behavior with respect to
earthquake intensity. This evaluation should
account for soil strength, degree of com-
paction, sorting (organization of the soil
4-12
information on ordering these maps, call 800 HELP-MAP; or write: USGS Information Services,
Box 25286, Denver, CO 80225; or fax 303 202-4693. On-line information is available at
.
contact NEIC, call 303 273-8500; or write: United States Geological Survey, National Earthquake
Information Center, Box 25046, DFC, MS 967, Denver, Colorado 80225; or fax 303 273-8450; or e-mail
sedas@gldfs.cr.usgs.gov. For on-line information, see .
-------
Getting Started—Considering the Site
Peak Acceleration (%g) with 10% Probability of Exceedance in 50 Years
site: NEHRP B-C boundary $
-1DO-
U.S. Geological Survey
National Seismic Hazard Mapping Project
USGS seismic impact maps like this one show the likelihood of occurance of an seismic event with
a specified peak acceleration.
Source: USGS National Earthquake Information Center .
particles), and saturation, as well as peak
acceleration of the potential earthquake.
After an evaluation of soil behavior, choose
appropriate earthquake protection-measures.
These might include shallower slopes, dike
and run-off control designs using conserva-
tive safety factors, and contingency plans or
backup systems for leachate collection should
the primary systems be disrupted. Unit com-
ponents should be able to withstand the
additional forces imposed by an earthquake
within acceptable margins of safety.
Additionally, well-compacted, cohesionless
embankments or reasonably flat slopes in
insensitive clay (clay that maintains its com-
pression strength when remolded) are less
likely to fail under moderate seismic shocks
(up to 0.15 g and 0.20 g). Embankments
made of insensitive, cohesive soils founded
on cohesive soils or rock may withstand even
greater seismic shocks. For earthen embank-
ments in seismic regions, consider designs
with internal drainage and core materials
resistant to fracturing. Prior to or during unit
construction in a seismic impact zone,
evaluate excavation slope stability to deter-
mine the appropriate grade of slopes to mini-
mize potential slip.
For landfills and waste piles, use shallower
waste side slopes, as steep slopes are more
vulnerable to slides and collapse during
earthquakes. Use fill sequencing techniques
that avoid concentrating waste in one area of
the unit for an extended period of time. This
4-13
-------
Getting Startedr—Considering the Site
prevents waste side slopes from becoming
too steep and unstable and alleviates differen-
tial loading of the foundation components.
Placing too much waste in one area of the
unit may lead to catastrophic shifting during
an earthquake or heavy seismic activity.
Shifting of this nature may cause failure of
crucial system components or of the unit in
general. ;
In addition, seismic impact zones have
design issues in common with fault areas,
especially concerning soil liquefaction and
earthquake-related stresses. To address lique-
faction, employ the soil improvement meth-
ods described in Table 1. Treating liquefiable
soils in the vicinity of the unit will improve
foundation stability and help prevent uneven
settling or possible collapse of heavily satu-
rated soils underneath or near the unit.
To protect against earthquake-related stress-
es, consider redundant liners and special
leachate collection and removal system com-
ponents, such as secondary liner systems,
composite liners, and leak detection systems
combined widi a low permeability soil layer.
These measures function as backups to the
primary containment and collection systems
and provide a greater margin of safety for
units during possible seismic stresses.
Examples of special leachate systems include
high-strength, flexible materials for leachate
containment systems; geomembrane liner sys-
tems underlying leachate containment sys-
tems; and perforated polyvinyl chloride or
high-density polyethylene piping in a bed of
gravel or other permeable material.
E. Unstable Areas
Unstable areas are locations susceptible to
naturally occurring or human-induced events
or forces capable of impairing the integrity of
a waste management unit. Naturally occur-
ring unstable areas include regions with poor
soil foundations, regions susceptible to mass
movement, or regions containing karst ter-
rain, which may include hidden sinkholes.
Unstable areas caused by human activity may
include areas near cut or fill slopes, areas
with excessive drawdown of ground water,
and areas where significant quantities of oil
or natural gas have been extracted. Siting in
an unstable area may make monitoring a site
or performing remediation,' if necessary,
impossible to do. Siting in an unstable area
should be avoided. If necessary, technical and
construction techniques should be consid-
ered to mitigate against potential damage.
The three primary types of failure diat can
occur in an unstable area are settlement, loss of
bearing strength, and sinkhole collapse.
Settlement can result from soil compression if a
unit is, or will be, located in an unstable area
over a thick, extensive clay layer. The unit's
weight may force water from the compressible
clay, compacting it and allowing the unit to set-
tle. Settlement may increase as waste volume
increases and may result in structural failure of
the unit if it was not properly engineered.
Settlement beneath a waste management unit
should be assessed and compared to the elon-
gation strength and flexibility properties of the
liner and leachate collection pipe system. Even
small amounts of settlement can seriously
damage leachate collection piping and sumps.
Engineer a unit to minimize the impacts of set-
tlement if it is, or will be in an unstable area.
Loss of bearing strength is a failure mode
that occurs in soils that tend to expand and
rapidly settle or liquefy Soil contractions and
expansions may increase the risk of leachate or
waste release. Another example of loss of bear-
ing strength occurs when excavation near the
unit reduces the mass of soil at the toe of the
slope, thereby reducing the overall strength
(resisting force) of the foundation soil.
Catastrophic collapse in the form of sink-
holes can occur in karst terrain. As water,
4-14
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Getting Started—Considering the Site
Sinkholes, like this one that occurred just north of Orlando, Florida in 1981, are a risk of
Karst terrain. Left: aerial view (note baseball diamond for scale); right: ground-level view.
Photos courtesy of City of Winter Park, Florida public relations office.
especially acidic water, percolates through
limestone, the soluble carbonate material dis-
solves, leaving cavities and caverns. Land
overlying caverns can collapse suddenly,
resulting in sinkholes that can be more than
100 feet deep and 300 feet wide.
How is it known if a prospective
site is in an unstable area?
Before designing a waste management unit
on a prospective site whose stability has not
previously been assessed, a stability assessment
study should be conducted by a qualified pro-
fessional. The qualified professional should
assess natural conditions, such as soil geology
and geomorphology, as well as both surface
and subsurface human-induced features or
events that could cause differential ground set-
tlement. Naturally unstable conditions can
become more unpredictable and destructive if
amplified by human-induced changes to the
environment. If a unit is to be built at an
assessed site that exhibits stability problems,
tailor the design to account for any instability
detected. A stability assessment may include
the following steps:
Screen for expansive soils. Such soils may
lose their ability to support a foundation
when subjected to certain natural events,
such as heavy rain, or human-made
events, such as explosions. Expansive soils
usually are clay-rich and, because of their
molecular structure, tend to swell and
shrink by taking up and releasing water.
Such soils include smectite (montmoril-
lonite group) and vermiculite days. In
addition, soils rich in white alkali (sodium
sulfate), anhydrite (calcium sulfate), or
pyrite (iron sulfide) also may swell as
water content increases. These soils are
more common in the arid western states.
Check for soil subsidence. Soils subject to
rapid subsidence include loesses, unconsoli-
dated clays, and wetland soils. Loess is a
wind-deposited, moisture-deficient silt that
tends to compact when wet. Unconsolidated
days can undergo considerable compaction
when oil or water is removed. Similarly, wet-
land soils, which by their nature are water-
bearing, are also subject to subsidence when
water is withdrawn.
4-15
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Getting Started—Considering the Site
Subsidence, slippage,
and other kinds of slope
failure can damage ;
structures.
Look for areas
subject to mass
movement or
slippage. Such.
areas are often
situated on
slopes and tend
to have rock or
soil conditions
conducive to
downhill sliding.
Examples of
mass movements
include
avalanches, land-
slides, and rock
slides. Some sites
may require cut-
ting or rilling
slopes during
construction. Such activities may cause
existing soil or rock to slip.
Search for karst terrain. Karst features are
areas containing soluble bedrock, such as
limestone or dolomite, that has been dis- \
solved and eroded by water, leaving char-
acteristic physiographic features including
sinkholes, sinking streams, caves, large
springs, and blind valleys. These areas are
subject to extreme incidents of differential
settlement, including complete ground
collapse. Karst features also can hamper
detection and control of leachate, which
can move rapidly through hidden conduits
beneath the unit. Karst maps, such as
Engineering Aspects of Karst, Scale
1:7,500,000, Map No. 38077-AW-NA-
07M-00, produced by the USGS12 and
state specific geological maps can be
reviewed to identify karst areas.
Scan for evidence of excessive drawdown
or oil and gas extraction. Removing under-
ground water can increase the effective
overburden on the foundation soils under-
neath the unit. Excessive drawdown of
water might cause settlement or bearing
capacity failure on the foundation soils.
Extraction of oil or natural gas can have
similar effects.
Investigate the geotechnical and geological
characteristics of the site. It is important to
establish soil strengths and other engineer-
ing properties. A geotechnical engineering
consultant can accomplish this by per-
forming standard penetration tests, field
vane shear tests, and laboratory tests. This
information will determine how large a
unit can be placed safely on the site. Other
soil properties to examine include water
content, shear strength, plasticity, and
grain size distribution.
Examine the liquefaction potential The liq-
uefaction potential of embankments, slopes,
and foundation soils must be determined.
Highly liquefiable soils are less conducive to
safe operation of a waste management unit.
Consult Section C above for more informa-
tion about liquefiable soils.
What can be done if a prospec-
tive site is in an unstable area?
It is advisable not to locate or expand a
waste management unit in an unstable area.
If a unit is, or will be located in such an area,
safeguard the structural integrity of the unit
by incorporating appropriate measures into
the design. If this is not done, the integrity of
the unit may be jeopardized. For example, to
safeguard the structural integrity of side
slopes in an unstable area, reduce slope
height, flatten slope angle, excavate a bench
in the upper portion of the slope, or buttress
slopes with compacted earth or rock fill.
Alternatively, build retaining structures, such
as retaining walls or slabs and piles. Other
approaches include geotextiles and geogrids
to provide additional strength, wick and toe
4-16
information on ordering this map, call 800 USA-MAPS; or write: USGS Information Services, Box
25286, Denver, CO 80225; or fax 303 202-4693; On-line information is available at
.
-------
Getting Started—Considering the Site
drains to relieve excess pore pressures, grout-
ing, and vacuum and wellpoint pumping to
lower ground-water levels. In addition, sur-
face drainage may be controlled to decrease
infiltration, thereby reducing the potential for
mud and debris slides.
Additional engineering concerns arise in
the case of waste management units in areas
containing karst terrain. The principal con-
cern with karst terrains is progressive or cata-
strophic subsurface failure due to the pres-
ence of sinkholes, solution cavities, and sub-
terranean caverns. The unpredictable and
sometimes catastrophic nature of subsidence
in these areas makes them difficult and
expensive to develop. Extensive subsurface
characterization studies should be completed
before designing and building in these areas.
Subsurface drilling, sinkhole monitoring, and
geophysical testing are direct means that can
be used to characterize a site. Geophysical
techniques include electromagnetic conduc-
tivity, seismic refraction, ground-penetrating
radar, and electrical resistivity. Use more than
one technique to confirm and correlate find-
ings and anomalies, and have a qualified geo-
physicist interpret the results of these explo-
rations.
Remote sensing techniques, such as aerial
photograph interpretation, can provide addi-
tional information on karst terrains. Surface
mapping can help provide an understanding
of structural patterns and relationships in
karst terrains. An understanding of local car-
bonate geology and stratigraphy can help
with the interpretation of both remote sens-
ing and geophysical data.
Incorporate adequate engineering controls
into any waste management unit located in
karst terrain. In areas where karst development
is minor, loose soils overlying the limestone
may be excavated or heavily compacted to
achieve the needed stability Similarly, in areas
where the karst voids are relatively small, the
voids may be filled with slurry cement grout
or other material.
Engineering solutions can try to compen-
sate for the weak geologic structures by pro-
viding ground supports. For example, ground
modifications, such as grouting or reinforced
raft foundations, could compensate for a lack
of ground strength in some karst areas. Raft
constructions, which are floating foundations
consisting of a concrete footing extending
over a very large area, reduce and evenly dis-
tribute waste loads where soils have a low
bearing capacity or where soil conditions are
variable and erratic. Note, however, that raft
foundations may not always prevent the
extreme collapse and settlement that can
occur in karst areas. In addition, due to the
unpredictable and catastrophic nature of
ground failure in unstable areas, the construc-
tion of raft foundations and other ground
modifications tends to be complex and can be
costly, depending on the size of the area.
F. Airport Vicinities
The vicinity of an airport includes not only
the facility itself but also large reserved open
areas beyond the ends of runways. If a unit is
intended to be sited near an airport, be aware
of issues that take on added importance in
such areas and become familiar with Federal
Aviation Administration (FAA) regulations
and guidelines. The chief concern associated
with waste management units near airports is
the hazard posed to aircraft by birds, which
often feed at units managing putrescible
waste. Planes can lose propulsion when birds
are sucked into jet engines, and may sustain
other damage in collisions with birds.
Another area of concern for landfills and
waste piles near airports is the height of the
accumulated waste. In such situations, exer-
cise caution when managing waste in units
that are significantly above ground level.
Industrial waste management units that do
4-17
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Getting Started—Considering the Site
not receive putrescible wastes should not
have a problem with birds.
How is it known if a prospective
site is in an airport vicinity?
If the prospective site is not located near
any airports, additional evaluation is not nec-
essary. If there is uncertainty whether the
prospective site is located near airports,
obtain local maps of the area using the
Internet or from the state and identify any
nearby public use airports. Topographic
maps available from USGS also provide a
suitable basis for determining airport loca-
tions. If necessary, FAA can provide informa-
tion on the location of all public-use airports.
In accordance with FAA guidance, if a new
unit or an expansion of an existing unit will
be within 5 miles of the end of a public-use
airport runway, the affected airport and the
regional FAA office should be notified to pro-
vide them an opportunity for review and
comment.
What can be done if a prospec-
tive site is in an airport vicinity?
If a unit is, or will be located within
10,000 feet of an airport used by jet aircraft
or within 5,000 feet of an airport used only
by piston-type aircraft, design and operate
the-unit so it does not pose a bird hazard to
aircraft and, for above-ground units, does not
interfere with flight patterns. If it appears
that height may be a concern, consider
entrenching the unit or choosing a site out-:
side the airport's flight patterns. The types of
waste handled at most nonhazardous indus-
trial units do not usually include attractive
food sources for birds, but if a unit handles
waste that may potentially attract birds, pre-
cautions should be taken to prevent birds
from becoming an aircraft hazard. Discourage
congregation of birds near a unit by prevent-
ing water from collecting on site; eliminating
or covering wastes that might serve as a food
source; constructing physical barriers, such
as a canopy of fine wires or nets strung
around the disposal and storage areas; using
visual deterrents, including realistic models
of the expected scavenger birds' natural
predators; employing sound deterrents, such
as cannon sounds, distress calls of scavenger
birds, or the sounds of the birds' natural
predators; or removing nesting and roosting
areas (unless such removal is prohibited by
the Endangered Species Act).
G. Wellhead Protection
Areas
Wellhead protection involves sheltering
the ground-water resources that supply pub-
lic drinking water systems. A wellhead pro-
tection area (WHPA) is the area most suscep-
tible to contamination surrounding a well-
head. WHPAs are designated and often regu-
lated to prevent public drinking water
sources from becoming contaminated. The
technical definition, delineation, and regula-
tion of WHPAs vary from state to state.
Contact the state environmental agency to
determine what wellhead protection mea-
sures are in place near prospective sites.
Section II of this chapter provides examples
of how some states specify minimum allow-
able distances between waste management
units and public water supplies, as well as
drinking water wells. Locating a waste man-
agement unit in a WHPA can create a poten-
tial avenue for drinking water contamination
through accidental release of leachate, conta-
minated run-off, or waste.
4-18
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Getting Started—Considering the Site
How is it known if a prospective
site is in a wellhead protection
area?
If the prospective site is not located near a
WHPA, further evaluation is not necessary. If
there is uncertainty regarding the proximity of
the prospective site to a WHPA, contact the
state environmental agency. A list of state well-
head protection program contacts is available
on EPA's web page at
,
and is included in Appendix III. Also, USGS
and NRCS both can provide maps that help in
delineating WHPAs. For further expertise,
contact local water authorities, or universities.
What can be done if a prospec-
tive site is in a wellhead
protection area?
If a new unit or lateral expansion will be
located in a WHPA or suspected WHPA, con-
sider design modifications to help prevent
any ground-water contamination. For waste
management units placed in these areas,
work with state regulatory agencies to ensure
that appropriate ground-water barriers are
installed between the unit and the ground-
water table. These barriers should be
designed using materials of extremely low
permeability, such as geomembrane liners or
low permeability soil liners. The purpose of
such barriers is to prevent any waste, or
water that has percolated through the waste,
from reaching the ground water and possibly
affecting the public drinking water source.
In addition to ground-water barriers, con-
sider using leachate collection, leak detection,
and run-off control systems. Leachate conta-
mination is possibly the greatest threat to a
public ground-water supply posed by a waste
management unit. Incorporating leachate col-
lection, leak detection, and run-off control
systems should further minimize leachate
from escaping into the ground water.
Control systems that separate storm-water
run-on from any water that has contacted
waste should also be provided. Proper control
measures that redirect storm water to the
supply source area should help alleviate this
tendency.
II. Buffer Zone
Considerations
Many states require buffer zones between
waste management units and other nearby
land uses, such as schools. The size of a
buffer zone often depends on the type of
waste management unit and the land use in
the surrounding areas. Consult with state reg-
ulatory agencies and local advisory boards
about buffer zones before constructing a new
unit or expanding an existing unit.
Buffer zones provide time and space to
mitigate situations where accidental releases
may cause adverse human health or environ-
mental impacts. These zones provide four
primary benefits: maintenance of quality of
the surrounding ground water, prevention of
contaminant migration off site, protection of
drinking water supplies, and minimization of
nuisance conditions perceived in surrounding
areas. The size of the buffer zone will be
directly related to the intended benefit.
Protecting ground water should be the
primary concern for all involved parties.
Ensure that materials processed and disposed
of at a unit are isolated from ground-water
resources. Placing a unit further from the
water table, and increasing the number of
physical barriers between the unit and the
4-19
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Getting Started—Considering the Site
Many nearby areas and land uses, such as
schools, call for consideration of buffer zones.
water table, improves ground-water protec-
tion. It is therefore advised that in addition to
incorporating a liner system into a waste
management unit's design, a site where an
adequate distance separates the bottom of a
unit from the water table should be selected
(see Appendix IV: State Buffer Zone
Considerations: Table 5 for a summary of the
most common minimum separation distances
between the bottom of a waste management
unit and the water table). In the event of a
release, dais separation distance will allow for
dilution and natural attenuation to protect
ground water.13
Additionally, in die event of an unplanned
release, an adequate buffer zone will allow
time for remediation activities to control con-
taminants before they spread off site. It also
will provide additional protection for drink-
ing water supplies. Drinking water supplies
include ground water, individual and com-
munity wells, lakes, reservoirs, and munici-
pal water treatment facilities.
Finally, buffer zones help maintain good
relations with the surrounding community by
protecting surrounding areas from noise,
dust, and odor that may be associated with a
unit. Buffer zones also help prevent access by
unauthorized people. For units located near
property boundaries, houses, or historic
areas, evergreen trees or earthen berms can
provide a buffer to reduce noise and odors.
Planting trees around a unit can also improve
the aesthetics of a unit, obstruct any view of
unsightly waste, and help protect property
values in the surrounding community.
A. Recommended Buffer
Zones
Check with state and local officials to
determine what buffer zones may apply to
industrial waste management units.14
Property boundaries. Waste management
units can present noise, odor, and dust
problems for residents or businesses locat-
ed on adjacent property, thereby diminish-
ing property values. Additionally, proximi-
ty to property boundaries can invite
increased trespassing, vandalism, and
scavenging.
Drinking water wells, surface-water bod-
ies, and public water supplies. Locating a
unit near or within the recharge area, for
sole source aquifers and major aquifers,
coastal areas, surface-water bodies, or pub-
lic water supplies, such as a community
well or water treatment facility, also raises
concerns. Releases from a waste manage-
ment unit may pose serious threats to
human health not only where water is
used for drinking, but also where surface
waters are used for recreation.
4-20
^Natural attenuation may be defined as chemical and biological processes that reduce contaminant con-
centrations.
^Appendix IV presents a summary of some state buffer zone recommendations.
-------
Getting Started—Considering the Site
Buffer zones can help protect endangered
species and their habitats.
Contamination of surface waters also
threatens plants and animals and their
habitats.
Houses or buildings. To minimize adverse
effects on adjacent properties, consider
incorporating a buffer zone or separation
distance into unit design. Consider planting
trees or bushes to provide a natural buffer
between a unit and adjacent properties.
B. Additional Buffer Zones
There are several other areas for which to
consider establishing buffer zones, including
critical habitats, park lands, public roads, and
historic or archaeological sites.
Critical habitats. These are geographical
areas occupied by endangered or threatened
species. These areas contain physical or bio-
logical features essential to the proliferation
of the species. When designing a unit near a
critical habitat, it is imperative that the criti-
cal habitat be conserved. A buffer zone can
help prevent the destruction or adverse
modification of a critical habitat and mini-
mize harm to endangered or threatened
species.15
Parklands. A buffer between a unit and
park boundaries helps maintain the aes-
thetics of the park land. Park lands pro-
vide recreational opportunities and a nat-
ural refuge for wildlife. Locating a unit too
close to these areas can disrupt recreational
qualities and natural wildlife patterns.
Public roads. A buffer zone will help
reduce unauthorized access to a unit,
reduce potential odor concerns, and
improve aesthetics for travelers on the
nearby road.
Historic or archaeological sites. A waste
management unit located in close proximi-
ty to one of these sites may adversely
impact the aesthetic quality of the site.
These areas include historic settlements,
battlegrounds, cemeteries, and Indian bur-
ial grounds. Check also whether a prospec-
tive site itself has historical or archaeologi-
cal significance.
Historic sites call for careful consideration
of buffer zones.
l->For the full text of the Endangered Species Act, go to the U.S. House of Representatives Internet Law
Library at .
4-21
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Getting Started—Considering the Site
In summary, check with local authorities
to ensure that placement of a new waste man-
agement unit or lateral expansion of an exist-
ing unit will not conflict with any local buffer
zone criteria. Also, review any relevant state
regulations that may specify buffer zones for
industrial waste management units. For new
units or lateral expansions of existing units
located near any sensitive areas as described in
this section, consider measures to minimize
any possible health, environmental, and nui-
sance impacts.
III. Local Land Use
and Zoning
Considerations
In addition to location and buffer zone
considerations, become familiar with any
local land use and zoning requirements. Local
governments often classify the land within
their communities into areas, districts, or
zones. These zones represent different use
categories, such as residential, commercial,
industrial, or agricultural. Zoning protects
public health and safety, property values, and
development trends. Consider the compati-
bility of a unit with nearby existing and
future land use and contact local authorities
early in the siting process. Local planning,
zoning, or public works officials can discuss
the development of a .unit, compliance with
local regulations, and available options. Local
authorities may impose conditions for pro-
tecting adjacent properties from potential
adverse impacts of unit.
Addressing local land use and zoning
issues during the siting process may prevent
these issues from becoming prominent con-
cerns later in the process. Land use and zon-
ing restrictions often address impacts on
community and recreational areas, historical
areas, and other critical areas. Consider the
proximity of a unit to such areas and evaluate
any potential adverse effects it may have on
these areas. For example, noise, dust, fumes,
and odors from construction and operation of
a unit could be considered a nuisance and
legal actions may be brought by local authori-
ties or nearby property owners.
In situations where land use and zoning
restrictions may cause difficulties in expand-
ing or siting a unit, work closely with local
authorities to learn about local land use and
zoning restrictions and minimize potential
problems. Misinterpreting or ignoring such
restrictions can cause complications with
intended development schedules or designs.
In many cases, the use of vegetation, fences,
or walls to screen activities may reduce
impacts on nearby properties. In addition, it
may be possible to request amendments,
rezonings, special exceptions, or variances to
restrictions. These administrative mechanisms
allow for flexibility in use and development
of land. Learning about local requirements as
early as possible in the process will maximize
the time available to apply for variances or
rezoning permits, or to incorporate screening
into the plans for a unit.
IV. Environmental
Justice
Considerations
In the past several years, there has been
growing recognition from communities and
federal and state governments that some
socioeconomic and racial groups may bear a
disproportionate burden of adverse environ-
mental effects from waste management activi-
ties. President Clinton issued Executive Order
12898, Federal Actions to Address
Environmentaljusti.ee in Minority Populations
and Low-Income Populations, on February 11,
4-22
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Getting Started—Considering the Site
1994. To be consistent with the definition of
environmental justice in this executive order,
identify and address, as appropriate, dispro-
portionately high and adverse human health
or environmental effects of waste manage-
ment programs, policies, and activities on
minority populations and low-income popu-
lations.
One of the criticisms made by advocates of
environmental justice is that local communi-
ties endure the potential health and safety
risks associated with waste management units
without enjoying any of the economic bene-
fits. During unit siting or expansions, address
environmental justice
concerns in a manner
that is most appropriate
for the operations, the
community, and the
state. Look for opportu-
nities to minimize envi-
ronmental impacts,
improve the surrounding
environment, and pur-
sue opportunities to
make the waste manage-
ment facility an asset to
the community. When
planning these opportunities, it is beneficial
to maintain a relationship with all involved
parties based on honesty and integrity, utilize
cross-cultural formats and exchanges, and
recognize industry, state, and local knowledge
of the issues. It is also important to take
advantage of all potential opportunities for
developing partnerships.
Examples of activities that incorporate
environmental justice issues include tailoring
activities to specific needs; providing inter-
preters, if appropriate; providing multilingual
materials; and promoting the formation of a
community/state advisory panel.
Tailor the public involvement activities to
the specific needs. Good public involve-
ment programs are site-specific—they take
into account the needs of the facility,
neighborhood, and state. There is no such
thing as a "one-size-fits-all" public involve-
ment program. Listening to each other
carefully will identify the specific environ-
mental justice concerns and determine the
involvement activities most appropriate to
address those needs.
Provide interpreters for public meetings.
Interpreters can be used to ensure the
information is exchanged. Provide inter-
preters, as needed, for the hearing
impaired and for any languages, other than
English, spoken by
a significant per-
centage of the audi-
ence.
Provide multilingual
fact sheets and
other information.
Public notices and
fact sheets should
be distributed in as
many languages as
necessary to ensure
that all interested
parties receive necessary information. Fact
sheets should be available for the visually
impaired in the community on tape, in
large print, or braille.
Promote the formation of a
community/state advisory panel to serve as
the voice of the community. The Louisiana
Department of Environmental Quality, for
example, encourages the creation of envi-
ronmental justice panels comprised of
community members, industry, and state
representatives. The panels meet monthly
to discuss environmental justice issues and
find solutions to any concerns identified
by the group.
4-23
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Getting Started—Considering the Site
Considering the Site Action Items
General Location Considerations
Q Check to see if the proposed unit site is
— In a 100-year floodplain;
— Near a wetland;
— Within 200 feet of an active fault;
— In a seismic impact zone;
— In an unstable area;
— Close to an airport; or
— Within a wellhead protection area.
Q If the proposed unit site is in any of these areas,
— Attempt to site the unit elsewhere first; or
— Design the unit to account for the area's characteristics and mitigate the unit's
impacts on such areas.
Buffer Zones
(Many states require bufifer zones between waste management units and other nearby land uses.)
D Check to see if the proposed unit site is near
— A property boundary;
— A drinking water well;
— A public water supply, such as a community well, reservoir, or water treatment
facility;
— A surface-water body, such as a lake, stream, river, or pond;
— Houses or other buildings;
— Critical habitats for endangered or threatened species;
— Park lands;
— A public road; or
— Historic or archaeological sites.
D If the proposed unit site is near any of these areas or land uses, determine how large a
buffer zone, if any, is appropriate between the unit and the area or land use.
4-24
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Getting Started—Considering the Site
Considering the Site Action Items (cont.)
Local Land Use and Zoning Restrictions
Q Contact local planning, zoning, and/or public works agencies to discuss restrictions that may
apply to the unit.
D Comply with any applicable restrictions, or obtain the necessary variances or exceptions.
Environmental Justice Issues
Q Determine whether minority or low-income populations would bear a disproportionate burden of any
environmental effects of the unit's waste management activities.
Q Work with the community to devise strategies to minimize any potential disproportionate burdens.
4-25
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Getting Started—Considering the Site
Resources
Bagchi, A. 1994. Design, construction, and monitoring of landfills. John Wiley & Sons Inc.
Das, B. M. 1990. Principles of geotechnical engineering. 2nd ed. Boston: PWS-Kent Publishing Co.
Illinois Department of Energy and Natural Resources. 1990. Municipal solid waste management options:
Volume II: Landfills.
Law, J., C. Leung, P. Mandeville, and A. H. Wu. 1996. A case study of determining liquefaction potential of a
new landfill site in Virginia by using computer modeling. Presented at WasteTech '95, New Orleans, LA
Oanuary).
Oregon Department of Environmental Quality. 1996. Wellhead protection facts. World Wide Web page:
.
Texas Natural Resource Conservation Commission. 1983. Industrial solid waste landfill site selection.
U.S. Army Corps of Engineers. 1995. Engineering and design: Design and construction of conventionally
reinforced ribbed mat slabs (RRMS). ETL 1110-3-471.
U.S. Army Corps of Engineers. 1995. Engineering and design: Geomembranes for waste containment applica-
tions. ETL 1110-1-172.
U.S. Army Corps of Engineers. 1992. Engineering and design: Bearing capacity of soils.
EM 1110-1-1905.
U.S. Army Corps of Engineers. 1992. Engineering and design: Design and construction of
grouted riprap. ETL 1110-2-334 ]
U.S. Army Corps of Engineers. 1984. Engineering and design: Use of geotextiles under riprap. ETL 1110-2-
286.
U.S. EPA. 1995. Decision-maker's guide to solid waste management, 2nd ed. EPA530-R-95-023.
U.S. EPA. 1995. RCRA Subtitle D (258) Seismic design guidance for municipal solid waste landfill facilities.
EPA600-R-95-05L
U.S. EPA. 1995. Why do wellhead protection? Issues and answers in protecting public drinking water supply
systems. EPA813-K-95-001.
U.S. EPA. 1994. Design, operation, and closure of municipal solid waste landfills. EPA625-R-94-008.
4-26
-------
Getting Started—Considering the Site
Resources (cont.)
U. S. EPA. 1994. Handbook: Ground water and wellhead protection. EPA625-R-94-001.
U. S. EPA. 1993. Guidelines for delineation of wellhead protection areas. EPA440-5-93-001.
U.S. EPA. 1993. RCRA Public involvement manual. EPA530-R-93-006.
U.S. EPA. 1993. Solid waste disposal facility criteria: Technical manual. EPA530-R-93-017.
U. S. EPA. 1992. Final comprehensive state ground-water protection program guidance. EPA100-R-93-001.
U. S. EPA. 1991. Protecting local ground-water supplies through wellhead protection.
EPA570-09-91-007.
U.S. EPA. 1990. Sites for our solid waste: A guidebook for effective public involvement.
EPA530-SW-90-019.
U. S. EPA. 1988. Developing a state wellhead protection program: A user's guide to assist state agencies
under the Safe Drinking Water Act. EPA440-6-88-003.
U.S. House of Representatives. 1996. Endangered Species Act. Internet Law Library. World Wide Web
page: .
University of Illinois Center for Solid Waste Management and Research, Office of Technology Transfer.
1990. Municipal solid waste landfills: Volume II: Technical issues.
University of Illinois Center for Solid Waste Management and Research, Office of Technology Transfer.
1989. Municipal solid waste landfills: Vol. I: General issues.
4-27
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-------
Part II
Protecting Air Quality
Chapter 5
Protecting Air Quality
-------
Contents
I. Federal Airborne Emission Control Programs 5-3
A. National Ambient Air Quality Standards 5-3
B. New Source Performance Standards 5-3
C. National Emissions Standards for Hazardous Air Pollutants 5-4
D.Title V Operating Permits 5-4
E. Federal Airborne Emission Regulations for Solid Waste Management Activities 5-9
1. Hazardous Waste Management Unit Airborne Emission Regulations 5-9
2. Municipal Solid Waste Management Landfill Airborne Emissions Regulations 5-9
3. Off-Site Waste and Recovery Operations NESHAP 5-9
E A Decision Guide to Applicable CAA Requirements 5-10
II. Assessing Risk 5-14
A. Assessing Risks Associated with Inhalation of Ambient Air 5-15
B.IWAIR Model .' 5-19
1. Emissions Model 5-19
2. Dispersion Model 5-19
3. Risk Model ...5-20
4. Estimation Process 5-20
5. Capabilities and Limitations of the Model 5-23
C. Site-Specific Risk Analysis 5-25
III. Emission Control Techniques 5-25
A. Controlling Particulate Matter (PM) 5-25
1. Vehicular Operations 5-27
2. Waste Placement and Handling 5-27
3. Wind Erosion 5-29
B. VOC Emission Control Techniques 5-29
1. Choosing a Site to Minimize Airborne Emission Problems 5-29
2. Pretreatment of Waste 5-30
3. Enclosure, of Units 5-30
4. Treatment of Captured VOCs 5-30
5. Special Considerations for Land Application Units 5-32
Protecting Air Quality Action Items 5-33
Resources 5-34
-------
Table of Contents
Figures:
Figure 1. Evaluating VOC Emission Risk 5-11
Figure 2. Conceptual Site Diagram 5-15
Figure3. Emissions from WMU 5-17
Figure 4. Forces That Affect Contaminant Plumes 5-18
Figure 5. IWAIR Approach for Developing Risk or Protective Waste Concentrations 5-21
Figure 6. Screen 1, Method, Met Station. WMU 5-22
Figure 7. Screen 2, Waste Managed 5-22
Tables:
Table 1. Industries for Which NSPSs Have Been Established 5-5
Table 2. Hazardous Air Pollutants (HAPs) Defined in Section 112 of the Clean Air Act
Amendments of 1990 •. 5-6
Table 3. Source Catagories with MACT Standards 5-8
Figure 4. Major Source Determination in Nonattainment Areas 5-12
Table 5. Source Characterization Models 5-26
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-------
Protecting Air Quality—Protecting Air Quality
Protecting Air Quality
Airborne particulates and toxic air emissions can cause human
health risks and damage the environment. Adopt controls to mini-
mize particulate emissions. If a facility's waste management units
are not addressed by requirements under the Clean Air Act, assess
risks associated with toxic air emissions using the model in this
guidance, and implement pollution prevention, treatment, or con-
trols to reduce risks. For facilities that must obtain a Clean Air Act
Title V permit, the permit is a good vehicle to address air emissions
from waste management units.
Health effects from airborne pol-
lutants can be minor and
reversible (such as eye irrita-
tion), debilitating (such as
asthma), or chronic and poten-
tially fatal (such as cancer). Potential impacts
depend on many factors, including the quan-
tity of air pollution to which people are
exposed, the duration of exposures, and the
effects associated with specific pollutants. An
air risk assessment takes these factors into
account to project risks posed at a particular
site or facility. Air releases from waste man-
This chapter wiE help you address the
following questions: " , -
• Is a particular facility subject to CAA
requirements?
* What is. an air risk assessment?
• Do waste management .units pose risks
from volatile air emissions?-
* What controls will; reduce particulate
and volatile emissions from a facility?
agement units include particulates or wind-
blown dust and toxic or hazardous contami-
nants. Toxic air pollutants are those pollu-
tants known or suspected to cause cancer or
other serious health effects such as reproduc-
tive effects or birth defects, or to cause
adverse environmental effects.1
We recommend that every facility imple-
ment controls to address emissions of air-
borne particulates. Particulates have immedi-
ate and highly visible impacts on surrounding
neighborhoods. They can affect human health
and may carry hazardous constituents off site
as well. Generally, controls are consistent with
good operating practices, and may not be too
costly.
For toxic air releases from industrial solid
waste management units, there are two sets of
questions you need to pursue. First, what reg-
ulatory requirements under the Clean air Act
(CAA) apply to the facility, and do those
requirements address waste management
units? The second question for facilities whose
waste management units are not addressed by
CAA requirements, is "are there risks from
toxic air releases that should be controlled?"
'From "Taking Toxics Out of the Air: Progress in Setting Maximum Achievable Control Technology: Standards
Under the Clean Air Act" U.S. EPA, Office of Air Quality Planning and Standards, Research Triangle Park, NC
27711, EPA451-K-98-001, February 1998.
5-1
-------
Protecting Air Quality—Protecting Air Quality
This Guide, provides two tools to help you
answer these questions. First, this chapter
includes an overview of the major emission
control requirements under the CAA and a
decision guide to evaluate which of these may
apply to a facility. Each facility subject to any
of these requirements must obtain a CAA Title
V operating permit. The decision guide will
help you to clarify some of the key facility
information you need to identify applicable
CAA requirements.
If your answers in the decision guide indi-
cate that the facility is or might be subject to
specific regulatory obligations, the next step is
to consult with EPA, state, or local air quality
program staff. Some CAA regulations are
industry-specific and operation-specific within
an industry, others are pollutant specific or
specific to a geographic area. EPA, state, or
local air quality managers can help you pre- |
cisely determine applicable requirements and
whether waste management units are
addressed by those requirements.
You may find that waste management units
are not addressed or that a specific facility
dearly does not fit into any regulatory catego-
ry under the CAA. It is then prudent to look
beyond immediate permit requirements to
assess risks associated with volatile organic
compounds (VOCs) released from the unit.
We recommend a two-tiered approach to this
assessment, depending on the complexity and
amount of site specific data you have.
Limited site-specific air assessment: The CD
ROM version of this Guide contains the
Industrial Waste Air Model (IWAIR). If a
waste contains any of the 95 constituents
included in the model, you can use this
risk model to assess whether VOC emis-
sions pose a risk that warrants additional
emission controls or that could be
addressed more effectively with pollution
prevention or waste treatment before place-
ment in the waste management unit.
Comprehensive Risk Assessment: This assess-
ment relies on a comprehensive analysis of
waste and site-specific data and use of
models designed to assess multi-pathway
exposures to airborne contaminants. There
are a number of modeling tools available
for this analysis. Consult closely with your
air quality management agency as you pro-
ceed.
Airborne emissions are responsible for the loss of visibility between the left and right pho-
tographs of the Grand Canyon. Source: National Park Service, Air Resources Division.
5-2
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Protecting Air Quality—Protecting Air Quality
I. Federal Airborne
Emission Control
Programs
Four major federal programs address air-
borne emissions that can degrade air quality.
For more information about the CAA and
EPA's implementation of it, see Appendix I or
visit the Technology Transfer Network, EPA's
premier technical web site for information
transfer and sharing related to air pollution
topics, at .
If the facility is subject to any CAA
requirements, the owners must obtain a per-
mit under Tide V of CAA and/or other state
air permitting programs. As part of the per-
mitting process, develop an emissions inven-
tory for the facility. Some states have addi-
tional permitting requirements. Whether or
not emissions from a waste management
unit(s) will be specifically addressed through
the permit process depends on a number of
factors, including the type of facility and state
permitting resources and priorities. It is pru-
dent, however, where there are no applicable
air permit requirements to assess whether
there may be risks associated with waste
management units and to address these risks.
directly by EPA. Instead, each state must sub-
mit a State Implementation Plan (SIP)
describing how it will achieve or maintain
NAAQS. Many SIPs call for airborne emission
limits on industrial facilities.
If a waste emits VOCs, which can be pre-
cursors to ozone, the waste management unit
could be affected by EPA's revised NAAQS for
ground-level ozone.3 EPA will phase out and
replace the previous 1-hour averaging time
ozone standard widi a new 8-hour averaging
time standard to protect over longer exposure
periods. The previous 1-hour standard of
0.12 parts per million (ppm) will be replaced
with a new 8-hour standard of 0.08 ppm.
Phasing in the new standard will take place in
several ways. States or areas of states that
have not been able to comply with current
0.12 ppm 1-hour standard will not be subject
to more stringent requirements until they
meet the 1-hour standard for three consecu-
tive years. States and areas already achieving
the 1-hour standard may be eligible to partic-
ipate in regional emission control strategies or
submit early SIPs to address the new 8-hour
standard. Consult with your state to deter-
mine whether efforts to comply with the
ozone NAAQS involve VOC emission limits
that apply to a specific facility.
A. National Ambient Air
Quality Standards
The CAA authorizes EPA to establish emis-
sion limits to achieve National Ambient Air
Quality Standards (NAAQS).2 EPA has desig-
nated NAAQS for the following criteria pollu-
tants: ozone, sulfur dioxide, nitrogen dioxide,
lead, paniculate matter (PM), and carbon
monoxide. The NAAQS establish individual
pollutant concentration ceilings that should
be rarely exceeded in a predetermined geo-
graphical area (National Ambient Air Quality
District (NAAQD)). NAAQS are not enforced
B. New Source
Performance Standards
New Source Performance Standards
(NSPSs) may apply to any building, structure,
facility, or installation which emits or may emit
an air pollutant for which a NAAQS (criteria
pollutants) exists. For industry categories,
NSPSs establish national technology-based
emission limits for criteria air pollutants,7 such
as paniculate matter (PM), or for their precur-
sors, such as VOCs. States have primary
responsibility for assuring that the NSPSs are
followed. These standards are distinct from
H2 U.S.C. § 7409
362 FR 38856 Quly 18, 1997)
5-3
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Protecting Ak Quality—Protecting Air Quality
NAAQS because they establish direct national
emission limits for specified sources, while
NAAQS establish air quality targets that states
meet using a variety of measures that include
emission limits. Table 1 lists industries for
which NSPSs have been established and loca-
tions of the NSPSs in the Code of Federal
Regulations. Check to see if any of the 74 New
Source Performance Standards (NSPSs)4 apply
to the facility.5 Any facility subject to a NSPS
must obtain a Title V operating permit (see sec-
tion D below.).
C National Emission Stan-
dards for Hazardous Air
Pollutants
Waste streams that are not hazardous waste
under RCRA may generate air pollutants that
have a hazardous air pollutant (HAP) regulato-
ry status under the CAA. Section 112 of the
CAA Amendments of 19906 requires EPA to
establish national standards to reduce HAP
emissions. Section 112(b) contains a list of
188 HAPs (see Table 2) to be regulated by
National Emission Standards for Hazardous
Air Pollutants (NESHAPs) or Maximum
Achievable Control Technology (MACT) stan-
dards, that are generally set on an industry-by-
industry basis.
MACT standards apply only to major
sources. A major source is defined as any sta-
tionary source or group of stationary sources
that (1) is located within a contiguous area
and under common control, and (2) emits or
has the potential to emit at least 10 tons per
year (tpy) of any single HAP or at least 25 tpy
of any combination of HAPs. All fugitive emis-
sions, including emissions from waste manage-
ment units, are to be taken into account in
determining whether a stationary source is a
major source. Each MACT standard limits spe-
cific operations, processes, and/or wastes that
are covered. Some MACT standards specifical-
ly cover waste management units, others do
not. If a facility is covered by a MACT stan-
dard, it must be permitted under Title V (see
below).
EPA has identified approximately 170 indus-
trial categories and subcategories that are or will
be subject to MACT standards. The CAA calls
for EPA to promulgate the standards in four
phases. Standards already promulgated in the
first two phases are listed in Table 3. The sched-
ule for the last two phases extends through
2000 (see Appendix I).
CAA also requires EPA to assess the risk to
public health remaining after the implementa-
tion of NESHAPs and MACT standards. EPA
must determine if more stringent standards are
necessary to protect public health with an ample
margin of safety. As a first step in this process
the CAA requires EPA to submit a Report to
Congress on its methods for making the health
risks from residual emissions determination. A
draft of this report was submitted to Congress
on April 14, 1998, and the final version is due
February 1, 1999. If significant residual risk
exists after application of a MACT, EPA must
promulgate health-based standards for that
source category to further reduce HAP emis-
sions. EPA must set residual risk standards with-
in 9 years after promulgation of each NESHAP
in the first phase group and within 8 years for
all other phases of source categories.
D. Title V Operating Permits
For many facilities, the new federal operat-
ing permit program established under Title V
of the CAA will cover all sources of airborne
emissions. It requires a permit for any facility
"40 CFR Part 60
'While NSPSs apply to new facilities, EPA also established emissions guidelines for existing facilities.
"42 U.S.C. § 7412.
5-4
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Protecting Air Quality—Protecting Air Quality
Table 1
Industries for Which NSPSs Have Been Established
For electronic versions of the 40 CFR Part 60 subparts referenced below, visit . Be sure to check the Federal Register for updates that may have been
published after this guidance.
Facility
Part 60
Subpart
Facility
40 CFR
Part 60
Subpart
Ammonium Sulfate Manufacture PP
Asphalt Processing &
Asphalt Roofing Manufacture UU
Auto/Id Truck Surface Coating
Operations MM
Basic Oxygen Process Furnaces after 6/11/73 N
Beverage Can Surface Coating Industry WW
Bulk Gasoline Terminals XX
Calciners and Dryers in Mineral Industry UUU
Coal Preparation Plants Y
Electric Utility Steam Generating Units after 9/18/78 DA
Equipment Leaks of VOC in Petroleum Refineries GGG
Equipment Leaks of VOC in SOCMI W
Ferroalloy Production Facilities Z
Flexible Vinyl & Urethane Coating & Printing FFF
Fossil-fuel Fired Steam Generators after 8/17/71 D
Glass Manufacturing Plants CC
Grain Elevators DD
Graphic Arts: Publication Rotogravure Printing QQ
Hot Mix Asphalt Facilities I
Incinerators E
Industrial Surface Coating, Plastic Parts TTT
Industrial Surface Coating-Large Appliances SS
Industrial-Commercial-Institutional Steam Gen.
Unit DB
Kraft Pulp Mills BB
Large Municipal Waste Combustors after 9/20/94 EB
Lead-Acid Battery Manufacturing Plants KK
Lime Manufacturing HH
Magnetic Tape Coating Facilities SSS
Medical Waste Incinerators (MWI) after 6/20/96 EC
Metal Coil Surface Coating TT
Metallic Mineral Processing Plants LL
Municipal Solid Waste Landfills after 5/30/91 WWW
Municipal Waste Combustors (MWQ EA
New Residential Wood Heaters AAA
Nitric Acid Plants G
Nonmetallic Mineral Processing Plants OOO
Onshore Natural Gas Processing Plants, VOC Leaks KKK
Onshore Natural Gas Processing: SO^ Emissions LLL
Petroleum Dry Cleaners, Rated Capacity ^ 84 Lb JJJ
Petroleum Refineries J
Petroleum Refinery Wastewater Systems QQQ
Phosphate Fertilizer-Wet Process Phosphoric Acid T
Phosphate Fertilizer-Superphosphoric Acid U
Phosphate Fertilizer-Diammonium Phosphate V
Phosphate Fertilizer-Triple Superphosphate W
Phosphate Fertilizers: GTSP Storage Facilities X
Phosphate Rock Plants NN
Polymer Manufacturing Industry DDD
Polymeric Coating of Supporting Substrates Fac. VW
Portland Cement Plants F
Pressure Sensitive Tape & Label Surface Coating RR
Primary Aluminum Reduction Plants S
Primary Copper Smelters P
Primary Lead Smelters R
Primary Zinc Smelters Q
Rubber Tire Manufacturing Industry BBB
Secondary Brass and Bronze Production Plants M
Secondary Lead Smelters L
Sewage Treatment Plants O
Small IndustyCommyinstitut. Steam
Generating Units DC
SOCMI - Air Oxidation Processes III
SOCMI - Distillation Operations NNN
SOCMI Reactors RRR
SOCMI Wastewater YYY
Stationary Gas Turbines GG
Steel Plants: Elec. Arc Furnaces after 08/17/83 AAA
Steel Plants: Electric Arc Furnaces AA
Storage Vessels for Petroleum Liquids K
Storage Vessels for Petroleum Liquids KA
Sulfuric Acid Plants H
Surface Coating of Metal Furniture EE
Synthetic Fiber Production Facilities HHH
Volatile Storage Vessel (Incl. Petroleum)
after 7/23/84 KB
Wool Fiberglass Insulation Manufacturing Plants PPP
5-5
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Protecting Air Quality—Protecting Air Quality
Table 2
HAPs Defined in Section 112 of the CAA Amendments of 1990
CAS# CHEMICALNAME CAS# CHEMICALNAME CAS# CHEMICALNAME
I • ' i i I
75070 Acetaldehyde
60355 Acetamide
75058 Acetonitrile
98862 Acetophenone
53963 2-Acetylaminofluorene
107028 Acrolein
79061 Acrylamide
79107 Acrylic acid
107131 Acrylonitrile
107051 Allyl chloride
92671 4-Aminobiphenyl
62533 Aniline
90040 o-Anisidine
1332214 Asbestos
71432 Benzene (including benzene
from gasoline)
92875 Benzidine
98077 Benzotrichloride
100447 Benzyl chloride
92524 Biphenyl :
117817 Bis(2-ethylhexyl)
phthalate (DEHP)
542881 Bis(chloromethyl)ether
75252 Bromoform
106990 1,3-Butadiene
156627 Calcium cyanamide
133062 Captan
63252 Carbaryl
75150 Carbon disulfide
56235 Carbon tetrachloride
463581 Carbonyl sulfide .
120809 Catechol
133904 Chloramben
57749 Chlordane
7782505 Chlorine
79 1 18 Chloroacetic acid
532274 2-Chloroacetophenone
108907 Chlorobenzene
510156 Chlorobenzilate
67663 Chloroform
107302 Chloromethyl methyl ether
126998 Chloroprene
1319773 Cresols/Cresylic acid
(isomers and mixture)
95487 o-Cresol
108394 m-Cresol
106445 p-Cresol
98828 Cumene
94757 2,4-D, salts and esters
3547044 DDE
334883 Diazomethane
132649 Dibenzofurans
96128 l,2-Dibromo-3-
chloropropane
84742 Dibutylphthalate
106467 l,4-Dichlorobenzene(p)
91941 3,3-Dichlorobenzidene
111444 Dichloroethyl ether
(Bis(2-chloroethyl)ether)
542756 1,3-Dichloropropene
62737 Dichlorvos
111422 Diethanolamine
121697 N,N-Diethyl aniline
(N ,N-Dimethylaniline)
64675 Diethyl sulfate
119904 3,3-Dimethoxybenzidine
60117 Dimethyl aminoazobenzene
119937 3,3'-Dimethyl benzidine
79447 Dimethyl carbamoyl chloride
68122 Dimethyl formamide
57 147 1 , 1-Dimethyl hydrazine
13 1 1 13 Dimethyl phthalate
77781 Dimethyl sulfate
534521 4,6-Dinitro-o-cresol, and
salts
51285 2,4-Dinitrophenol
121142 2,4-Dinitrotoluene
123911 1,4-Dioxane
(1 ,4-Diethyleneoxide)
122667 1,2-Diphenylhydrazine
106898 Epichlorohydrin (1-Chloro-
2,3-epoxypropane)
106887 1,2-Epoxybutane
140885 Ethyl acrylate
100414 Ethyl benzene
51796 Ethyl carbamate (Urethane)
75003 Ethyl chloride
(Chloroethane)
106934 Ethylene dibromide
(Dibromoethane)
107062 Ethylene dichloride
(1 ,2-Dichloroethane)
107211 Ethylene glycol
151564 Ethylene imine (Aziridine)
75218 Ethylene oxide
96457 Ethylene thiourea
75343 Ethylidene dichloride
(1 , 1-Dichloroethane)
50000 Formaldehyde
76448 Heptachlor
118741 Hexachlorobenzene
87683 Hexachlorobutadiene
77474 Hexachlorocyclopentadiene
67721 Hexachloroethane
822060 Hexamethylene-1,6-
diisocyanate
680319 Hexamethylphosphoramide
110543 Hexane
302012 Hydrazine
7647010 Hydrochloric acid
7664393 Hydrogen fluoride
(Hydrofluoric acid)
123319 Hydroquinone
78591 Isophorone
58899 Lindane (all isomers)
108316 Maleic anhydride
67561 Methanol
72435 ; Methoxychlor
74839 ' Methyl bromide
(Bromomethane)
74873 Methyl chloride
(Chloromethane)
71556 , Methyl chloroform
(1, 1, 1-Trichloroe thane)
78933 Methyl ethyl ketone
(2-Butanone)
60344 Methyl hydrazine
74884 Methyl iodide
(lodomethane)
108101 Methyl isobutyl ketone
(Hexone)
624839 Methyl isocyanate
80626 Methyl methacrylate
1634044 Methyl ten butyl ether
1 0 1 144 4,4-Methylene bis(2
-chloroaniline)
75092 Methylene chloride
(Dichloromethane)
101688 Methylene diphenyl
diisocyanate (MDI)
101779 4,4'-Methylenedianiline
91203 Naphthalene
98953 Nitrobenzene
92933 4-Nitrobiphenyi
100027 4-Nitrophenol
79469 2-Nitropropane
684935 N-Nitroso-N-methylurea
62759 N-Nitrosodimethylamine
59892 N-Nitrosomorpholine
56382 Parathion
82688 Pentachloronitrobenzene
(Quintobenzene)
87865 Pentachlorophenol
5-6
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Protecting Air Quality—Protecting Air Quality
Table 2 (continued)
HAPs Defined in Section 112 of the CAA Amendments of 1990
CAS# CHEMICAL NAME
*CALNAME
CAS# CHEMICAL NAME
108952 Phenol
106503 p-Phenylenedlamine
75445 Phosgene
7803512 Phosphine
7723140 Phosphorus
85449 Phthalic anhydride
1336363 Polychlorinated
biphenyls (Aroclors)
1120714 1,3-Propane sultone
57578 beta-Propiolactone
123386 Propionaldehyde
114261 Propoxur (Baygon)
78875 Propylene dichloride
(1,2-Dichloropropane)
75569 Propylene oxide
75558 1,2-Propylenimine
(2-Methyl aziridine)
91225 Quinoline
106514 Quinone
100425 Siyrene
96093 Styrene oxide
1746016 2,3,7,8-Tetrachlorodi-
benzo-p-dioxin
79345 1,1,2,2-Tetrachloroethane
127184 Tetrachloroethylene
(Perchloroethylene)
7550450 Titanium tetrachloride
108883 Toluene
95807 2,4-Toluene diamine
584849 2,4-Toluene diisocyanate
95534 o-Toluidine
8001352 Toxaphene (chlorinated
camphene)
20821 1,2,4-Trichlorobenzene
79005 1,1,2-Trichloroethane
79016 Trichloroethylene
95954 2,4,5-Trichlorophenol
88062 2,4,6-Trichlorophenol
121448 Triethylamine
582098 Trifluralin
540841 2,2,4-Trimethylpentane
108054 Vinyl acetate
593602 Vinyl bromide
75014 Vinyl chloride
75354 Vinylidene chloride
(1,1-Dichloroethylene)
1330207 Xylenes (isomers and
mixture)
95476 o-Xylenes
108383 m-Xylenes
106423 p-Xylenes
[none] Antimony Compounds
[none] Arsenic Compounds
(inorganic including arsine)
[none] Beryllium Compounds
[none] Cadmium Compounds
[none] Chromium Compounds
[none] Cobalt Compounds
[none] Coke Oven Emissions
[none] Cyanide Compounds'
[none] Glycol ethers'
[none] Lead Compounds
[none] Manganese Compounds
[none] Mercury Compounds
[none] Fine mineral fibers'
[none] Nickel Compounds
[none] Polycylic Organic Matter1
[none] Radionuclides (incl. radon)c
[none] Selenium Compounds
NOTE: For all listings above which contain the word "compounds'" and for glycol ethers, the following applies: Unless otherwise
specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony,
arsenic, etc.) as part of that chemical's infrastructure.
'X'CN where X = H1 or any other group where a formal dissociation may occur. For example KCN or Ca(CN)2.
'Includes mono- and di-ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-(OCH2CH2)n-OR' where n = 1, 2,
or 3, R = alkyl or aryl groups, and R1 = R, H, or groups which, when removed, yield glycol ethers with the structure: R-
(OCH2CH)n-OH. Polymers are excluded from the glycol category
'Includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers (or other mineral derived
fibers) of average diameter 1 micrometer or less.
•"Includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100 °C.
CA type of atom which spontaneously undergoes radioactive decay.
emitting or having the potential to emit more
than 100 tpy of any air pollutants.7 Permits
are also required for all sources subject to
MACT or NSPS standards. All airborne emis-
sion requirements that apply to an industrial
facility, including emission limitations as well
as operational, monitoring, and reporting
requirements, will be incorporated in its oper-
ating permit. A Title V permit provides a sin-
gle tool to address all emissions from facilities
subject to CAA requirements.
Under the new program, operating permits
that meet federal requirements will generally
be issued by state agencies. In developing
individual permits, states can determine
whether to explicitly apply emission limita-
tions and controls to waste management
units. See section F (A Decision Guide to
Applicable CAA Requirements), and consult
with federal, state, and local air program staff
to determine if your waste management unit
is subject to airborne emission limits and
'Under CAA Section 302(g), "air pollutant" is defined as any pollutant agent or combination of agents, includ-
ing any physical, chemical, biological, or radioactive substance or matter -which is emitted into or otherwise
enters the ambient air.
5-7
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Protecting Air Quality—Protecting Air Quality
Table 3
Source Categories With MACT Standards*
Source Category
Federal Register Page
Source Category
Federal Register Page
Non-Ferrous Metals Processing
Secondary Lead Smelling 60 FR 32587 (6/23/95)
Primary Aluminum Reduction 62 FR 52383 (10/7/97)
Primary Copper Smelting 63 FR 19582 (4/20/98)(P)
Primary Lead Smelting 63 FR 19200 (4/17/98)(P)
Coke Ovens
Steel Pickling HCI Process
Mineral Products Processing
Mineral Wool Production
Portland Cement
Manufacturing
Wool Fiberglass
Manufacturing
58 FR 57898 (10/27/93)
62FR49051(9/18/97)(P)
62 FR 25369 (5/8/97) (P)
63 FR 14181 (3/24/98XP)
62 FR 15227 (3/21/97) (P)
Petroleum and Natural Gas Production and Refining
Oil & Natural Gas Production 63 FR 06288 (2/6/98)(P)
Natural Gas Transmission and
Storage 63 FR 06288 (2/6/98)(P)
Petroleum Refineries 60 FR 43244 (8/18/95)
liquids Distribution
Gasoline Distribution
Marine Vessel Loading
Surface Coating Processes
Aerospace Industries
Magnetic Tapes
Printing/Publishing
Shipbuilding and Repair
Wood Furniture
Waste Treatment and Disposal
Off-Site Waste and Recovery
Operations
59 FR 64303 (12/14/95)
60 FR 48399 (9/19/95)
60 FR 45948 (9/1/95)
59 FR 64580 (12/15/94)
61 FR 27132 (5/30/96)
60 FR 64330 (12/15/95)
60 FR 62930 (12/7/95)
61 FR 34141 (7/1/96)
Agricultural Chemicals Production
Agricultural Chemicals
Production 62 FR 60565 (11/10/97) (P)
Pharmaceutical Production Processes
Pharmaceutical Production 62 FR 15753 (4/2/97) (P)
Polymers and Resins Production
Aoylonkrile-Butadiene-Styrene 61 FR 48207 (9/12/96)
Butyl Rubber
Epichlorohydrin Elastomers
Epoxy Resins Production
Ethylene-Propylene Rubber
Flexible Polyurethane Foam
61 FR 46905 (9/5/96)
61 FR 46905 (9/5/96)
60 FR 12670 (3/8/95)
61 FR 46905 (9/5/96)
61 FR 68405 (12/27/96) (P)
Hypalon™
Methyl Methacrylate-Acrylo-
nitrile-Butadiene-Styre ne
Methyl Methacrylate-Buta-
diene-Styrene Terpolymers
Neoprene
Nitrile Butadiene Rubber
Nitrile Resins Production
Non-Nylon. Polyamides
Polybutadiene Rubber
Polyether Polyols
Polyethylene Terephthalate
Polystyrene
Polysulfide Rubber
Styrene-Acrylonitrile
Styrene-Butadiene Rubber,
Latex
61FR 46905 (9/5/96)
61FR 48207 (9/12/96)
61 FR 48207 (9/12/96)
61FR 46905 (9/5/96)
61FR 46905 (9/5/96)
61 FR 48207 (9/12/96)
60 FR 12670 (3/8/95)
61FR 46905 (9/5/96)
62 FR 46803 (9/4/97) (P)
61 FR 48207 (9/12/96)
61 FR 48207 (9/12/96)
61FR 46905 (9/5/96)
61 FR 48207 (9/12/96)
61 FR 46905 (9/5/96)
Production of Inorganic Chemicals
Phosphate Fertilizers .
Production 61 FR 68429 (12/27/96) (P)
Phosphoric Acid
Manufacturing 61 FR 68429 (12/27/96) (P)
Production, of Organic Chemicals
Synthetic Organic Chemicals 59 FR 19402 (4/22/94),
Manufacturing
62 FR 2721 (1/17/97)
Miscellaneous Processes
Chromic Acid Anodizing
Commercial Dry Cleaning
(Perchloroethylene)
Commercial Sterilization
Facilities ;
Decorative Chromium
Electroplating
Halogenated Solvent
Cleaners
Hard Chromium
Electroplating
Industrial Cleaning
(Perchloroethylene)
Industrial Dry Cleaning
(Perchloroethylene)
Industrial Process Cooling
Towers
Pulp and Paper Production
Tetrahydrobenzaldehyde
Production
60 FR 4947 (1/25/95)
58 FR 49353 (9/22/93)
59 FR 62585 (12/6/94)
60 FR 4948 (1/25/95)
59 FR 61801 (12/2/94)
60 FR 4948 (1/25/95)
58 FR 49353 (9/22/93)
58 FR 49353 (9/22/93)
59 FR 46339 (9/8/94)
63 FR 18503 (4/15/98)
62 FR 44614 (8/22/97) (P)
5-8
* This table contains final rules and proposed rules (P) promulgated as of May 1998. It does not
identify corrections or clarifications to rules.
-------
Protecting Air Quality—Protecting Air Quality
controls under CAA regulations. (See
Appendix II for a listing of EPA regional and
state air pollution control agency contacts.)
E. Federal Airborne
Emission Regulations for
Solid Waste
Management Activities
While EPA has not established airborne
emission regulations for nonhazardous indus-
trial waste management units under RCRA,
standards developed for hazardous waste man-
agement units and municipal solid waste land-
fills (MSWLFs) may serve as a guide in evalu-
ating the need for controls at specific units.
1. Hazardous Waste Management
Unit Airborne Emission Regulations
Under Section 3004(n) of RCRA, EPA
established standards for monitoring and
control of airborne emissions from hazardous
waste treatment, storage, and disposal facili-
ties. Subparts AA, BB, and CC of 40 CFR Part
265 address VOC releases from process vents,
equipment leaks,, tanks, surface impound-
ments, and containers. (See Appendix III for
a more detailed discussion of Subparts AA,
BB, and CC.) Subpart CC establishes require-
ments for hazardous waste surface impound-
ments containing waste with volatile organic
content greater than 500 ppm by weight. It
exempts units managing wastes that have
been treated to reduce concentrations of
organics. For non-exempt surface impound-
ments, Subpart CC requires the use of covers
and closed vent systems that reduce VOC
emissions by 95 percent. Closed vent systems
include vapor recovery units, flares, and
other combustion units.
2. Municipal Solid Waste Landfill
Airborne Emission Regulations
On March 12, 1996, EPA promulgated air-
borne emission regulations for new and exist-
ing MSWLFs.8 These regulations apply to all
new MSWLFs constructed on or after May 30,
1991 and to existing landfills with total design
capacities of 2.5 million megagrams per year
(Mg/yr) (approximately 2.75 million tpy) that
have accepted waste on or after November 8,
1987. In addition to methane, MSWLFs poten-
tially emit criteria pollutants and HAPs in the
gases generated during waste decomposition, as
well as in combustion of the gases in control
devices, and from other sources, such as dust
from vehicle traffic and emissions from leachate
treatment facilities or maintenance shops.
Under the regulations, any affected MSWLF
that emits more than 50 Mg/yr (55 tpy) of non-
methane organic compounds (NMOC) is
required to install controls.
Best demonstrated technology requirements
for both new and existing municipal landfills
prescribe installation of a well-designed and
well-operated gas collection system' and a con-
trol device. The collection system should be
designed to allow expansion for new cells that
require controls. The control device (presumed
to be a combustor) must demonstrate either an
NMOC reduction of 98 percent by weight in
the collected gas or an outlet NMOC concen-
tration of no more than 20 parts per million by
volume (ppmv).
3. Off-Site Waste and Recovery
Operations NESHAP
On July 1, 1996, EPA established standards
for off-site waste and recovery operations
(OSWRO) that emit HAPs.9 To be covered by
OSWRO, a facility must emit or have the
potential to emit at least 10 tpy of any single
HAP or at least 25 tpy or any combination of
HAPs. It must receive waste, used oil, or used
961 ER 9905
'61FR34139
5-9
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Protecting Air Quality^-Protecting Air Quality
solvents from off-site that contain one or more
HAPs.10 In addition, the facility must operate
one of the following: a hazardous waste treat-
ment, storage, or disposal facility; RCRA-
exempt hazardous wastewater treatment opera-
tion, nonhazardous wastewater treatment facili-
ty other than a publicly owned treatment facili-
ty; RCRA-exempt hazardous waste recycling or
reprocessing operation, used solvent recovery
operation, or used oil recovery operation.
OSWRO contains MACT standards to
reduce HAP emissions from tanks, surface
impoundments, containers, oil-water separa-
tors, individual drain systems, other material
conveyance systems, process vents, and equip-
ment leaks. For example, OSWRO establishes
two levels of air emission controls for tanks
depending on tank design capacity and die
maximum organic HAP vapor pressure of the
off-site material in the tank. For process vents,
control devices must achieve a minimum of 95
percent organic HAP emission control. To con-
trol HAP emissions from equipment leaks, the
facility must implement leak detection and
repair work practices and equipment modifica-
tions for those equipment components contain-
ing or contacting off-site waste having a total
organic HAP concentration greater than 5 per-
cent by weight.
F. A Decision Guide to
Applicable CAA
Requirements
The following series of questions is designed
to help you identify CAA requirements that
may apply to a facility. This will not give you
definitive answers, but can provide a useful
starting point for consultation with federal,
state, or local permitting authorities to deter-
mine which requirements apply to a specific
facility and whether such requirements address
waste management units at the facility. If a
facility is clearly not subject to CAA require-
ments, we recommend that you assess potential
risks from VOC emissions at a waste manage-
ment unit using the IWAIR or a site-specific
risk assessment.
The following steps provide a walk through
of this evaluation process:
1. Determine emission from the unit:
a) Determine VOC's present in the waste
(waste characterization). Then assume all
the VOC's are emitted from the unit; or
b) Estimate emissions using an emissions
model. This also requires waste characteri-
zation. The CHEMDAT8 model is a logical
model for these types of waste units. You
can use the EPA version on the Internet or
the one contained in the modeling tool for
this guidance; or
c) Measure emissions from the unit. This
is the most resource intensive alternative.
2. Is the waste management unit part of
an industrial facility which is subject to a
CAA Tide V operating permit?
A facility is subject to a Title V operating
permit if it is considered a major source of air
pollutants, or is subject to a NSPS, NESHAP, or
Title IV acid rain provision.11 As part of the per-
mitting process, the facility should develop, an
emissions inventory. Some states have addition-
al permitting requirements. If a facility is sub-
ject to a Title V operating permit, all airborne
emission requirements that apply to an indus-
trial facility, including emission limitations as
well as operational, monitoring, and reporting
requirements, will be incorporated in its oper-
ating permit. Consult with appropriate federal,
state, and local air program staff to determine
whether your waste management unit is sub-
ject to air emission limits and controls.12
5-10
"OSWRO identified aprdximatery 10 HAPs to be covered, This HAP list is a subject of the CAA Section 112 list
"EPA can designate additional source categories subject to Title V operating permit requirements.
"Implementation of air emission controls may generate new residual waste. Ensure that these wastes are
managed appropriately, in compliance with state requirements and consistent with this guidance.
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Protecting Air Quality—Protecting Air Quality
Figure 1. Evaluating VOC Emission Risk
| Characterize waste for potential air emissions |
Is the unit part
of an industrial facility
which is subject to a CAA Title V
operating permit by virtue of being:
a. considered a major source; or
b. subject to NSPSs; or
c. considered a major source of HAPs and subject to
NESHAP or MACT standards; or
d. subject to the acid rain program; or
e. a unit subject to the
OSWRO NESHAP?
does
the permit
specifically address\7^
waste managemen
units?
Facility is subject
to an air permit.
does
the waste
contain any of the
95 listed
contaminants?
Conduct a risk evaluation using either.
a. Industrial Waste Air
Model
b. Site-specific risk
assessment
Conduct a more site-specific
risk assessment
Is
the total
risk for the unit
acceptable?
Reduce risk to acceptable levels
using treatment, controls or waste
minimization
Operate the unit in accordance with the
recommendations of this guidance.
5-11
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Protecting Air Quality—Protecting Air Quality
If you answer yes to any of the questions in
items a. through e. below, the facility is subject
to a Title V operating permit. Consult with the
appropriate federal, state, and/or local permit-
ting authority.
Whether or not emissions from waste man-
agement unit(s) will be specifically addressed
through the permit process depends on a num-
ber of factors, including the type of facility and
CAA requirements and state permitting
resources and priorities. It is prudent, however,
to look where there are not applicable air per-
mit requirements, to assess whether there may
be risks associated with waste management
units and to address these potential risks.
If you answer no to all the questions below,
continue to Step 3.
a. Is the facility considered
a major source?
If the facility meets any of the following
three definitions, it is considered a major
source (under 40 CFR § 70.2) and subject
to Title V operating permit requirements.
1. Any stationary source or group of sta-
tionary sources that emits or has the
potential to emit at
least 100 tpy of any
air pollutant. Major Source
Stationary soorca is defined as any
buidling, structure, fecility, or installation
which emits or may emit any air pollutant
that is located within a contiguous area
and under common control
An air poButant is defined as any air pol-
lutant agent or combination of agents,
including a physical, chemical, biological,
radioactive substance or matter which is
emitted into or otherwise enters the ambi-
ent air
3. A stationary source or group of station-
ary sources subject to the nonattainment
area provisions of CAA Title I that emits,
or has the potential to emit, above the
threshold values for its nonattainment area
category. The nonattainment area category
and the source's emission levels for VOCs
and NO*, particulate matter (PM-10), and
carbon monoxide (CO) determine whether
the stationary source meets the definition
of a "major source." For nonattainment
areas, stationary sources are considered
"major sources" if they emit or have the
potential to emit at least the levels found
in Table 4.
If yes, the facility is subject to a Title V
Table 4.
Determination in Nonattainment Areas
2. Any stationary
source or group of
stationary sources
that emits or has the
potential to emit at
least 10 tpy of any
single HAP or at
least 25 tpy of any
combination of
HAPs.
Nonattainment
Area Category13
Marginal or
Moderate
Serious
Severe
Extreme
VOCsorNOx
100 tpy
50 tpy
25 tpy
10 tpy
PM-10
100 tpy
70 tpy
—
—
CO
100 tpy
50 tpy
—
—
5-12
"The nonattainment categories are based upon the severity of the area's pollution problems. The five cate-
gories for VOCs and NOx range from Moderate to Extreme. Moderate areas are the closest to meeting the
attainment standard, and require the least amount of action. Nonattainment areas with more serious air quali-
ty problems must implement various control measures. The worse the air quality, the more controls areas will
have to implement. PM-10 and CO have only two categories, Moderate and Serious.
-------
Protecting Air Quality—Protecting Air Quality
operating permit. Consult with the appropri-
ate federal, state, and/or local permitting
authority.
If no, continue to determine whether the
facility is subject to a Title V operating permit.
b. Is the facility subject to
NSPSs?
Any stationary source subject to a standard
of performance under 40 CFR Part 60 is sub-
ject to NSPS. (A list of NSPSs can be found in
Table 1.)
If yes, the facility is subject to a Title V oper-
ating permit. Consult with the appropriate fed-
eral, state, and/or local permitting authority.
If no, continue to determine if the facility
is subject to a Title V operating permit.
c. Is the facility a major
source of HAPs as defined
by Section 112 of CAA and
subject to a NESHAP or
MACT standard?
Under Title V of CAA, an operating permit
is required for all facilities subject to a MACT
standard. NESHAPs or MACT standards are
national standards to reduce HAP emissions.
Each MACT standard specifies particular
operations, processes, and/or wastes that are
covered. EPA has identified approximately
170 source categories and subcategories that
are or will be subject to MACT standards.
(Table 3 above lists the source categories for
which EPA has promulgated MACT standards
during the first two phases of MACT standard
promulgation.) To be subject to a MACT
standard, you must be a major source or an
area source (see sidebar for definitions).
If yes, the facility should be permitted
A major source is defined as any station-
ary source or group of stationary sources
that emits or has the potential to emit at
least 10 tpy of any single hazardous air
pollutant (HAP) or at least 25 tpy of any
combination of HAPs.
An area sorace is any stationary source
which is not a major source bwt which
may be subject to controls. Area sources
represent a collection of facilities and
emission, points for a specific geographic
area. Most area sources are small, but the
collective volume o£ large aumbeis of
iacilities can be a concern in densely
developed areas, such as •urban neighbor-
hoods and industrial areas. Examples of
areas sources subject to MACT standards
mdude chromic add anodizing, commer-
cial sterilization facilities, decorative
chromium electroplating, hard chromium
electroplating, secondary lead smelting,
arid halogenated solvent cleaners.
HABsi are any of the 188 pollutants listed
m Section 112(b) of CAA. (Table 2 above
identifies the.188 HAPs.}
under CAA Title V Consult with the appro-
priate federal, state, and/or local permitting
authority.
If no, continue to determine if the facility
is subject to a Title V operating permit.
d. Is the facility subject to
the acid rain program
under Title IV of CAA?
If the facility, such as a fossil-fuel fired
power plant, is subject to emission reduction
requirements or limitations under the acid rain
program, it is subject to a Title V operating
5-13
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Protecting Air Quality5—Protecting Air Quality
permit (40 CFR § 72.6). The acid rain pro-
gram focuses on the reduction of annual sulfur
dioxide and nitrogen oxides emissions.
If yes, the facility is subject to CAA Tide V
permitting. Consult with the appropriate fed-
eral, state, and/or local permitting authority.
When you consult with the appropriate
permitting authority, be sure to clarify whether
waste management units at the facility are
addressed by the requirements. If waste man-
agement units will not be addressed through
the permit process, we recommend that you
evaluate VOC emission risks.
If no, continue to determine if the facility
is subject to a Title V operating permit.
e. Is the waste management
unit subject to the
OSWRO NESHAP?
This is just an example of the types of
questions you will need to answer to deter-
mine whether a NESHAP or MACT standard
covers your facility.
To be covered by the OSWRO standards,
your facility must meet all these conditions:
1. Be identified as a major source of
HAP emissions
2. Receive waste, used oil, or used sol-
vents from off site that contain one or
more HAPs.14
3. Operate one of the following six
types of waste management or recovery
operations (see 40 CFR § 63.680):
• Hazardous waste treatment, storage,
or disposal facility;
• RCRA-exempt hazardous wastewater
treatment operation;
• Nonhazardous wastewater treatment
facility other than a publicly owned
treatment facility;
• RCRA-exempt hazardous waste recy-
cling or reprocessing operation;
• Used solvent recovery operations; or
• Used oil recovery operations.
If yes, the unit should be covered by the
OSWRO standards and Title V permitting.
Consult with the appropriate federal, state,
and/or local permitting authority.
If no, continue to Step 3. The next series
of questions will help you consider options
for conducting an air risk evaluation.
3. Conduct a risk evaluation using one of
the following options:
a. Use IWAIR included in this guidance if
your unit contains any of the 95 contami-
nants that are covered in the model.
b. Initiate a site-specific risk assessment
for individual units. (For surface
impoundments, a methodology is set forth
in Preferred and Alternative Methods for
Estimating Air Emissions from Wastewater
Collection and Treatment, Volume II:
Chapter 5, Emission Inventory
Improvement Program, March 1997.) Total
all target constituents from all applicable
units and consider emissions from other
sources at the facility as well.
II. Assessing Risk
The air in our atmosphere is ubiquitous
and essential for biotic life. Additionally, it acts
as a medium for the transport of airborne con-
tamination and, therefore, constitutes an expo-
sure pathway of potential concern. Models
that can predict the fate and transport of
chemical emissions in the atmosphere can
provide an important tool for evaluating and
"OSWRO identified approximately 100 HAPs to be covered. This HAP list is a subset of the CAA Section 112
list. -
5-14
-------
Protecting Air Quality—Protecting Air Quality
protecting air quality. Included in this guid-
ance is the Industrial Waste Air Model
(IWAIR). This model was developed to assist
facility managers, regulatory agency staff, and
the public in evaluating inhalation risks from
waste management unit emissions. Although
IWAIR is simple to use, it is still essential to
understand the basic concepts of atmospheric
modeling to be able to interpret the results and
understand the nature of any uncertainties.
The purpose of this section is to provide gen-
eral information on the atmosphere, chemical
transport in the atmosphere, and evaluation of
risks associated with inhalation of chemicals so
you can understand important factors to con-
sider when performing a risk assessment for
the air pathway.
From a risk perspective, it is unquestion-
able that humans are continuously exposed
to air and the presence of chemicals in air is
important to consider in any type of assess-
ment. If pollutants build up to high concen-
trations in a localized area, human health
may be compromised. The concentration of
chemicals in a localized area and the resulting
air pollution that may occur in the atmos-
phere is dependent upon the quantity and
the rate of the emissions stream from a source
and the ability of the air to disperse the
chemicals. Both meteorological and geo-
graphic conditions in a local area will influ-
ence the emission rate and subsequent dis-
persion of a constituent. For example, the
meteorologic stability of the atmosphere, a
factor dependent on air temperature, influ-
ences whether the emission stream will rise
and mix with a larger volume of air (resulting
in the dilution of pollutants) or if the emis-
sions stream will remain close to the ground.
Figure 2 is a conceptual diagram of a waste
site showing potential paths of human expo-
sure through air.
A. Assessing Risks
Associated with
Inhalation of Ambient
Air
In any type of risk assessment, there are
basic steps that are necessary for gathering and
evaluating data. These steps include: identifica-
tion of chemicals of concern, source character-
ization, exposure assessment, and risk charac-
terization. Each of these steps is described
below as it applies specifically to risk resulting
Figure 2. Conceptual Site Diagram
Dispersion _ ...
Wind
Volatilization -'•" •'•'•' "
r^O } Partteulates
•' v:.'.-' Deposition
5-15
-------
Protecting Air Quality—Protecting Air Quality
from the inhalation of organic chemicals emit-
ted from WMUs to the ambient air. This
overview is presented to assist you in under-
standing conceptually the information dis-
cussed in the IWAIR section (Section II), since
many of these steps will be automatically per-
formed for you by the model.
Identification of Chemicals of Concern
A preliminary step in any risk assessment
is the identification of chemicals of concern.
These are the chemicals present that are
anticipated to have potential health effects as
a result of their concentrations and/or toxici-
ty factors. An assessment is performed for a
given source, to evaluate chemical concentra-
tions and toxicity of different chemicals.
Based on these factors along with potential
mechanisms of transport and exposure path-
ways, the decision is made to include or
exclude chemicals in the risk assessment.
Toxicity benchmarks are identified in this
step as well.
Source Characterization
In this step, the critical aspects of the
source (e.g., type of WMU, size, chemical
concentrations, location) are described.
When modeling an area source, such as those
included in this guidance, the amount of a
given chemical that volatilizes and disperses
from a source is critically dependent on the
total surface area exposed. The source char-
acterization should include information on
the surface area and elevation of the unit.
The volatilization is also dependent on other
specific attributes related to the waste man-
agement practices. Waste management prac-
tices of importance include application fre-
quency in land application units and the
degree of aeration that occurs in a surface
impoundment. The overall content of the
waste being deposited in the WMU is also
important in projecting volatilization since
the nonvolatile component can, depending
on its chemical characteristics, bind volatiles
and prevent their emission to the ambient air.
Source characterization involves defining
each of these key parameters for the WMU
being modeled. The accuracy of projections
concerning volatilization of chemicals from
WMUs into ambient air is improved if more
site-specific information is used in character-
izing the source.
Exposure Assessment
The goal of an exposure assessment is to
estimate the amount of a constituent that is
available and is taken in by an individual,
typically referred to as a receptor. An expo-
sure assessment is performed in two steps: 1)
the first step uses fate and transport model-
ing to determine the constituents concentra-
tion in air at a specified receptor location
and, 2) the second step estimates the amount
of the constituent the receptor will intake by
identifying life-style activity patterns. The
first step, the fate and transport modeling,
uses a combination of an emission and dis-
persion model to estimate the amount of
chemical that individuals residing and/or
working within the vicinity of the source are
exposed to through inhalation of ambient air.
When a chemical volatilizes from a WMU
into the ambient air, it is subjected to a num-
ber of forces that result in its diffusion and
transport away from the point of release.
In modeling the movement of the volatile
chemical away from the WMU, it is often
assumed that the chemical behaves as a plume
(i.e., the chemical is continuously emitted into
the environment) whose movement and diffu-
sion are modeled to produce estimated air
concentrations at points of interest. This emis-
sion is illustrated in Figure 3.
The pattern of diffusion and movement of
chemicals that volatilize from WMUs
depends on a number of interrelated factors.
5-16
-------
Protecting Air Quality—Protecting Air Quality
Figure 3. Emissions from a WMU
Wind
Plume
Emission Source
(landfill)
The ultimate concentration and fate of emis-
sions to the air are most significantly impact-
ed by three meteorologic conditions: atmos-
pheric stability, wind speed, and wind direc-
tion. These meteorologic factors interact to
determine the ultimate concentration of a
pollutant in a localized area.
Atmospheric stability: The stability of the
atmosphere is influenced by the vertical tem-
perature structure of the air above the emis-
sion source. In a stable environment, there is
little or no movement of air parcels, and,
consequently, little or no movement and mix-
ing of contaminants. In such a stable air envi-
ronment, chemicals become "trapped" and
unable to move. Conversely, in an unstable
environment there is significant mixing and
therefore greater dispersion and ultimately,
dilution of the plume.15
Prevailing wind patterns and their interac-
tion with land features: The nature of the
wind patterns immediately surrounding the
WMU can significantly impact the local air
concentrations of airborne chemicals.
Prevailing wind patterns combine with topo-
graphic features such as hills and buildings to
affect the movement of the plume. Upon
release, the initial direction that emissions
will travel is the direction of the wind. The
strength of the wind will determine how
dilute the concentration of the pollutant will
be in that direction. For example, if a strong
wind is present at the time the pollutants are
released, it is likely the pollutants will rapidly
leave the source and become dispersed quick-
ly into a large volume of air.
In addition to these factors affecting the
diffusion and transport of a plume away from
its point of release, the concentration of spe-
cific chemicals in a plume can also be affect-
ed by depletion. As volatile chemicals are
transported away from the WMU, they can be
removed from the ambient air through a
number of depletion mechanisms including
wet deposition (the removal of chemicals due
to precipitation) and dry deposition (the
removal of chemicals due to the forces of
gravity and impacts of the plume on features
such as vegetation). Chemicals can also be
transformed chemically as they come in con-
tact with the sun's rays (i.e., photochemical
degradation). Figure 4 illustrates the forces
acting to transport and deplete the contami-
nant plume.
Because the chemicals being considered in
IWAIR are volatiles and semi-volatiles and the
distances of transport being considered are
relatively short, the removal mechanisms
shown in the figure are likely to have a rela-
tively minor effect on plume concentration
(both wet and dry deposition have signifi-
cantly greater effects on airborne particulates)
15An example of an unstable air environment is one in which the sun shining on the earth's surface has resulted
in warmer air at the earth's surface. This warmer air will tend to rise, displacing any cooler air that is on top of
it. As these air parcels essentially switch places, significant mixing occurs.
5-17
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Protecting Air Quality—Protecting Air Quality
Figure 4. Forces That Affect Contaminant Plumes.
Building
Wake
Effects
Wet Deposition
Dry Deposition
Gravity
•%....,-
Deposition/Depletion
Topographic
Features
Photochemical
Degradation
ffir
4 AtSr
Thermal
Mixing
Cooler
Air
'Hot
Air
and therefore are not considered.
Once the constituent's ambient outdoor
concentration is determined, the receptor's
extent of contact with the pollutant must be
characterized. This step involves determining
the location and activity patterns relevant to
the receptor being considered. In IWAIR, the
receptors are defined as residents and workers
located at fixed distances from the WMU, and
the only route of exposure considered for
these receptors is the inhalation of volatiles.
The activity patterns are used to determine the
intake of the constituent. Intake estimates
quantify the extent to which the individual is
exposed to the contaminant and are a function
of the breathing rate, exposure concentration,
exposure duration, exposure frequency, expo-
sure averaging time (for carcinogens), and
body weight. Estimated exposures are present-
ed in terms of the mass of the chemical per
kilogram of receptor body weight per day.
Risk Characterization
The concentrations that an individual
takes into his or her body that were deter-
mined during the exposure assessment phase
are combined with toxicity values to generate
risk estimates. Toxicity values used in IWAIR
include inhalation-specific cancer slope fac-
tors (CSFs) for carcinogenic effects and refer-
ence concentrations (RfCs) for noncancer
effects. These are explained in the general
risk section under the building partnerships
chapter. Using these toxicity values, risk esti-
mates are generated for carcinogenic effects
and noncancer effects. Risk estimates for car-
cinogens are summed by IWAIR.
5-18
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Protecting Air Quality—Protecting Air Quality
B. IWAIR Model
IWAIR is an interactive computer program
with three main components: an emissions
model; a dispersion model to estimate fate
and transport of constituents through the
atmosphere and determine ambient air con-
centrations at specified receptor locations;
and a risk model to calculate either the risk
to exposed individuals or the waste con-
stituent concentrations that can be protective-
ly managed in the unit. The program requires
only a limited amount of site-specific infor-
mation, including facility location, WMU
characteristics, waste characteristics, and
receptor information. A brief description of
each component follows. The IWAIR
Technical Background Document contains a
more detailed explanation of each.
1. Emissions Model
The emissions model uses waste character-
ization, WMU, and facility information to
estimate emissions for 95 constituents. The
emission model selected for incorporation
into IWAIR is EPA's CHEMDAT8 model. This
model has undergone extensive review by
both EPA and industry representatives and is
publicly available from EPA's Web page,
.
To facilitate emission modeling with
CHEMDAT8, IWAIR prompts the user to pro-
vide the required waste- and unit-specific data.
Once these data are entered, the model calcu-
lates and displays chemical-specific emission
rates. If users decide not to develop or use the
CHEMDAT8 rates, they can enter their own
site-specific emission rates (g/m2-s).
2. Dispersion Model
IWAIR's second modeling component esti-
mates dispersion of volatilized contaminants
and determines air concentrations at specified
receptor locations, using default dispersion
factors developed with EPA's Industrial
Source Complex, Short-Term Model, version
3 (ISCST3). ISCST3 was run to calculate dis-
persion for a standardized unit emission rate
(1 }ig/m2 - s) to obtain a unitized air concen-
tration (UAC), also called a dispersion factor,
which is measured in ]Vm3 per ug/m2 -s. The
total air concentration estimates are then
developed by multiplying the constituent-
specific emission rates derived from CHEM-
DAT8 (or from another source) with a site-
specific dispersion factor. Running ISCST3 to
develop a new dispersion factor for each loca-
tion/WMU is very time consuming and
requires extensive meteorological data and
technical expertise. Therefore IWAIR incorpo-
rates default dispersion factors developed by
ISCST3 for many separate scenarios designed
to cover a broad range of unit characteristics,
including:
• 29 meteorological stations, chosen to
represent the nine general climate
regions of the continental U.S.;
• 4 unit types;
• 14 surface area sizes for landfills,
land application units and surface
impoundments, and 7 surface area
sizes and 2 heights for waste piles;
• 6 receptor distances from the unit
(25, 50, 75, 150, 500, 1000 meters)
placed in...
• 16 directions in relation to the edge
of the unit.
The default dispersion factors were derived
by modeling many scenarios with various
combinations of parameters, then choosing as
the default the maximum dispersion factor
for each waste management unit/surface
area/meteorological station/receptor distance
combination.
Based on the size and location of a unit,
as specified by a user, IWAIR selects an
5-19
-------
Protecting Air Quality—Protecting Air Quality
appropriate dispersion factor from the
default dispersion factors in the model. If the
user specifies a unit surface area that falls
between two of the sizes already modeled, a
linear interpolation method will estimate dis-
persion in relation to the two closest unit
sizes.
Alternatively, a user may enter a site-spe-
cific dispersion factor developed by conduct-
ing independent modeling with ISCST3 or
with a different model and proceed to the
next step, the risk calculation.
3. Risk Model
The third component to the model com-
bines the constituent's air concentration with
receptor exposure factors and toxicity bench-
marks to calculate either the risk from con-
centrations managed in the unit or the waste
concentration (Cw) in the unit that should
not be exceeded to protect human health. In
calculating either estimate, the model applies
default values for exposure factors, including
inhalation rate, body weight, exposure dura-
tion, and exposure frequency. These default
values are based on data presented in EPA's
Exposure Factors Handbook (U.S. EPA, 1997)
and represent average exposure conditions.
1WAIR maintains standard health bench-
marks (cancer slope factors for carcinogens
and reference concentrations for noncarcino-
gens) for 95 constituents. These health
benchmarks are from the Integrated Risk
Information System (IRIS) and the Health
Effects Assessment Summary Tables (HEAST)
(U.S. EPA, 1997a, 1998). The IWAIR uses
these data to perform either a forward calcu-
lation to obtain risk estimates or a backward
calculation to obtain protective waste con-
centration estimates.
4. Estimation Process
Figure 5 provides an overview of the step-
wise approach the user follows to calculate
risk or protective waste concentration esti-
mates with IWAIR. The seven steps of the
estimation process are shown down the right
side of the figure, and the user input require-
ments are specified to the left of each step.
As the user provides input data, the program
proceeds to the next step. Each step of the
estimation process is discussed below.
a. Select Calculation Method. Select
one of two calculation methods. Use the
forward calculation to arrive at chemical-
specific and cumulative risk estimates if
the user knows the concentrations of con-
stituents in the waste. Use the backward
calculation method to estimate protective
waste concentrations not to be exceeded in
new units. The screen where this step is
performed is shown in Figure 6.
b. Identify Waste Management Unit.
Four WMU types can be modeled: surface
impoundments (Sis), land application
units (LAUs), active landfills (LFs), and
wastepiles (WPs). For each WMU, you
will be asked to specify some design and
operating parameters such as surface area,
depth for surface impoundments and
landfills, height for wastepiles, and tilling
depth for LAUs. The amount of unit spe-
cific data needed as input will vary
depending on whether the user elects to
develop CHEMDAT8 emission rates.
IWAIR provides default values for several
of the operating parameters that the user
may choose, if appropriate.
c. Define Waste Managed. Specify con-
stituents and concentrations in the waste if
you choose a forward calculation to arrive at
chemical specific risk estimates. If you
choose a backward calculation to estimate
protective waste concentrations, then specify
constituents of concern. The screen where
this step is performed is shown in Figure 7.
5-20
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Protecting Air Quality—Protecting Air Quality
Figure 5. IWAIR Approach for Developing Risk or Protective Waste Concentrations:
This figure shows the steps in the tool to assist the user in developing risk or
protective waste concentration estimates.
. V
Calculation option
,1
-• v^-lfP^O
i-i!tll*i§iiJ^--L. ^'J$
' v •:..*' w;^y.£W ~sv xv-^'^'r*".•''•• • -;v '.^ •„- ••F;,^5^;-:J>
:' «;_|^^p;»rfe^n5ris*'p;|».g.,d»|^e«;;;|^:;i
Forward Calculation to Risk
Or
Backward Calculation to Protective
Waste Concentration
Land Application Unit(LAU)
Waste Pile (WP)
Surface Impoundment (SI)
aerated and quiescent
LandfiB(LF)
CHEMDAT8
Or
User Specified Emission Rates
ISCST3 Default Dispersion Factors
Or
User-specified Dispersion Factors
Calculates ambient air concentrations for
receptor based on emission and
1. Chemical-specific Carcinogenic Risk
2. Chemical-specific Non-carcinogenic Risk
3. Total Cancer Risk
Or
I * Cwforwastswatera {mg/L)
| • Cw for solid wastes (mg/kg)
5-21
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Protecting Air Quality—Protecting Air Quality
Figure 6. Screen 1, Method, Met Station. WMU.
Sertctsd »Wooi-iA39i«ISaOonfor SKo
*
Figure 7. Screen 2, Waste Managed.
Ocic •**«»>"
To F4x»v8 Charted hM««K»mw
-------
Protecting Air Quality—Protecting Air Quality
d. Determine Emission Bates. You can
elect to develop CHEMDAT8 emission
rates or provide your own site-specific
emission rates for use in calculations.
IWAIR will also ask for facility location
information to link the facility's location to
one of the 29 IWAIR meteorological sta-
tions. Data from the meteorological sta-
tions provide wind speed and temperature
information needed to develop emission
estimates. In some circumstances the user
may already have emissions information
from monitoring or a previous modeling
exercise. As an alternative to using the
CHEMDAT8 rates, a user may provide
their own site-specific emission rates
developed with a different model or based
on emission measurements.
e. Determine Dispersion. The user can
provide site-specific unitized dispersion
factors (ug/m3 per ug/m2-s) or have the
model develop dispersion factors based on
user-specified WMU information and the
IWAIR default dispersion data. Because a
number of assumptions were made in
developing the IWAIR default dispersion
data (for example, flat terrain was
assumed), you may elect to provide site-
specific dispersion factors which can be
developed by conducting independent
modeling with ISCST3 or with a different
model. Whether you use IWAIR or provide
dispersion factors from another source,
specify distance to the receptor from the
edge of the WMU and the receptor type
(i.e., resident or worker). These data are
used to define points of exposure.
£ Calculate Ambient Air Concentra-
tion. For each receptor, the model com-
bines emission rates and dispersion data to
estimate ambient air concentrations for all
waste constituents of concern.
g. Calculate Results. The model calcu-
lates results by combining estimated ambi-
ent air concentrations at a specified expo-
sure point with receptor exposure factors
and toxicity benchmarks. Presentation of
results depends on whether you chose a
forward or backward calculation:
Forward calculation: Results are estimates of
cancer and non-cancer risks from inhalation
exposure to volatilized constituents in the
waste. If risks are too high, options are: 1)
implement unit controls to reduce volatile air
emissions; 2) implement pollution prevention
or treatment to reduce volatile organic com-
pound (VOC) concentrations before the
waste enters the unit; or 3) conduct a full
site-specific risk assessment to more precisely
characterize risks from the unit.
Backward calculation: Results are estimates of
constituent concentrations in waste that can
be protectively managed in the unit so as not
to exceed a denned risk level (e.g., 1 x lO^or
hazard quotient of 1) for specified receptors.
This information should be used to deter-
mine preferred characteristics for wastes
entering the unit. There are several options if
it appears that planned waste concentrations
may be too high: 1) implement pollution pre-
vention or treatment to reduce VOC concen-
trations in the waste; 2) modify waste man-
agement practices to better control VOCs (for
example, use closed tanks rather than surface
impoundments); or 3) conduct a full site-spe-
cific risk assessment to more precisely charac-
terize risks from the unit.
5. Capabilities and Limitations
of the Model
In many cases, IWAIR will provide a rea-
sonable alternative to conducting a full-scale
site-specific risk analysis to determine if a
WMU poses unacceptable risk to human
health. However, because the model can
5-23
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Protecting Air Quality—Protecting Air Quality
accommodate only a limited amount of site-
specific information, it is important to under-
stand it's capabilities and recognize situations
when it may not be appropriate - when
another model would be a better choice.
Capabilities
• The model provides a reasonable, conser-
vative representation of VOC inhalation
risks associated with waste management
units. !
• The model is easy-to-use and requires a
minimal amount of data and expertise.
• The model is flexible and provides fea-
tures to meet a variety of user needs:
• A user can enter emission and/or dis
persion factors derived from another
model (perhaps to avoid some of the
limitations below) and still use
IWAIR to conduct a risk evaluation.
• The model can run a forward calcu-
lation from the unit or a backward
calculation from the receptor point.
• A user can modify health bench-
marks (HBNs) and target risk level,
when appropriate and in consulta-
tion with other stakeholders.
limitations
• Chemicals of Concern. If waste contains
chemicals that (1) are not included in the
model and (2) have human health effects
and may be present in concentrations
sufficient to pose a risk to public health
via inhalation exposure, the model will
not fully characterize risks for that WMU
since these additional chemicals would
be excluded from consideration.
• Release Mechanisms and Exposure
Routes. The model considers exposures
from breathing ambient air. It does not
address potential risks attributable to
paniculate releases nor does it address
risks associated with indirect routes of
exposure (i.e, non-inhalation routes of
exposure). Additionally, in the absence
of user-specified emission rates, volatile
emission estimates are developed with
CHEMDAT8 based on unit- and
waste-specific data. The CHEMDAT8
model was developed to address only
volatile emissions from waste manage-
ment units. Competing mechanisms
such as runoff, erosion, and leaching are
not accounted for in the model. In so
much as these competing processes actu-
ally occur, the model would tend to
slightly overestimate the volatile emis-
sions. On the other hand, one could
interpret this situation as being represen-
tative of WMUs that have leachate con-
trols, such as liners, or erosion and
runoff controls. Such controls would
tend to inhibit these processes and result
in more volatile emissions.
l Waste Management Practices. The user
specifies a number of unit-specific para-
meters that significantly impact the
inhalation pathway (e.g., size, type, and
location of WMU, which is important in
identifying meteorological conditions).
However, the model cannot accommo-
date information concerning control
technologies such as covers that might
influence the degree of volatilization
(e.g., whether a wastepile is covered
immediately after application of new
waste). In this case, it may be necessary
to generate site-specific emission rates
and enter those into IWAIR.
I Terrain and Meteorological Conditions. If
a facility is located in an area of interme-
diate or complex terrain or with unusual
meteorological conditions, it may be nec-
essary to either (1) generate site-specific
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Protecting Air Quality—Protecting Air Quality
air dispersion modeling results for the
site and enter those results into the pro-
gram, or (2) use a site-specific risk model-
ing approach different from IWAIR. The
model will inform the user which of the 29
meteorological stations is used for a facility.
If the local meteorological conditions are
very different from the site chosen by the
model, it would be more accurate to
choose a different model.
The terrain type surrounding a facility can
impact air dispersion modeling results and
ultimately risk estimates. In performing air
dispersion modeling to develop the IWAIR
default dispersion factors, it was assumed
that the facility was located in an area of
simple or flat terrain. The Guideline on Air
Quality Models (U.S. EPA, 1993) can assist
users in determining whether a facility is
in an area of simple, intermediate, or com-
plex terrain.
Receptor Type and Location, IWAIR has
predetermined adult worker and resident
receptors, six receptor locations, and
predetermined exposure factors. The
program cannot be used to characterize
risk for other possible exposure scenarios.
For example, the model can not evaluate
receptors that are closer to the unit than
25 meters or those that are further from
the unit that 1000 meters.
C. Site-specific Risk
Analysis
IWAIR is not the only model that may be
applicable to a site. In some cases, a site-spe-
cific risk assessment may be more advanta-
geous. A site-specific approach can be tai-
lored to accommodate the individual needs of
a particular WMU. Such an approach would
rely on site-specific data and on the applica-
tion of existing fate and transport models.
Table 5 summarizes available emissions
and/or dispersion models that may be applied
in a site-specific analysis. Practical considera-
tions include the source of the model(s), the
ease in obtaining the model(s), and the
nature of the model(s) (i.e., is it proprietary),
and the availability of site-specific data
required for use of the model. Finally, the
model selection process should determine
whether or not the model has been verified
against analytical solutions, other models,
and/or field data. Proper models can be
selected based on the physical and chemical
attributes of the site in question. However, as
with all modeling, the state authority should
be consulted prior to investing significant
resources in a site-specific analysis. The state
may have preferred models and/or may be
able to help plan the analysis.
III. Emission Control
Techniques
A. Controlling Particulate
Matter (PM)
PM consists of airborne solid and liquid
particles. When PM is very small, it is easily
inhaled and trapped in the lungs, where it
can cause various health problems. PM also
impacts the environment by decreasing visi-
bility and harming plants as well as trans-
porting hazardous constituents offsite. We
recommend that facilities adopt controls to
address emissions of airborne particulates.
Solid PM that becomes airborne directly or
indirectly as a result of human activity, is
referred to as fugitive dust16 and it can be gen-
erated from a number of different sources. The
most common sources of fugitive dust at waste
management units include vehicular traffic on
unpaved roads and land-based units, wind
erosion from land-based units, and waste han-
dling procedures. Developing a fugitive dust
16Fugitive emissions are defined as emissions not caught by a capture system and therefore exclude PM emitted
from exhaust stacks with control devices.
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Protecting Ak Quality—Protecting Air Quality
Model Name
CHEMDAT8
ISCST3
COMPDEP
Toxic Screening Model
(TSCREEN)
Table 5
Source Characterization Models
Summary
The CHEMDAT8 model allows the user to conduct source and chemi-
cal specific emissions modeling. CHEMDAT8 is a Lotus 1-2-3
spreadsheet that includes analytical models to estimate volatile organ-
ic compound emissions from treatment, storage, and disposal facility
processes under user-specified input parameters. CHEMDAT8 calcu-
lates the fractions of waste constituents of interest that are distributed
among pathways (partition fractions) applicable to the facility under
analysis.
Emissions modeling using CHEMDAT8 is conducted using data
entered by the user for unit-specific parameters. The user may
choose to override the default data and enter their estimates for these
unit-specific parameters. Thus, modeling emissions using CHEM-
DAT8 can be done with a limited amount of site-specific information.
Available at , hotline at
(919) 541 5610 for more information.
A steady-state Gaussian plume dispersion model that can estimate
concentration, dry deposition rates (particles only), and wet deposi-
tion rates. Is applicable for continuous emissions , industrial source
complexes, rural or urban areas, simple or complex terrain, transport
distances of less than 50 km, and averaging times from hourly to
annual
Available at
The COMPDEP model was developed to calculate air concentration
and deposition fluxes, particularly in areas of complex terrain. This
model uses standard meteorological data to produce estimates of
annual average concentration, total annual dry deposition, and wet
deposition flux at individual receptor sites. COMPDEP accounts for
pollutant deposition and terrain adjustments.
This model was developed for and is only applicable in rural areas.
Available at
Performs emission rate, pool evaporation , and natural and dense gas
dispersion calculations. TSCREEN uses simple methods, and therefore
is primarily used for screening. Little or no modeling experience is
required to use this model.
Source:
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Protecting Air Quality—Protecting Air Quality
control plan is an efficient way to tackle these
problems. The plan should include a descrip-
tion of all operations conducted at the unit, a
map, a list of all fugitive dust sources at the
unit, and a description of the control measures
that will be used to minimize fugitive dust
emissions. OSHA has established standards for
occupational exposure to dust (see 29 CFR §
1910.1000). Check to see if the state also has
regulations or guidance concerning dust or
fugitive emission control.
PM emissions at waste management units
vary with the physical and chemical character-
istics of waste streams; the volume of waste
handled; the size of the unit, its location, and
associated climate; and waste transportation
and placement practices. The subsections
below discuss the main PM-generating opera-
tions and identify emission control techniques.
1. Vehicular Operations
Waste and cover material are often trans-
ported to units using trucks. If the waste has
the potential for PM to escape to the atmos-
phere during transport, cover the waste with
tarps or place wastes in containers such as
double bags or drums17
A unit may also use vehicles to construct
lifts in landfills, apply liquids to land applica-
tion units, or dredge surface impoundments.
Consider using "dedicated" equipment—vehi-
cles that operate only within the unit and are
not routinely removed from the unit to per-
form other activities. This practice reduces
the likelihood that equipment movement will
spread contaminated PM outside the unit. To
control PM emissions when equipment must
be removed from the landfill unit, such as for
maintenance, a wash station can remove any
contaminated material from the equipment
before it leaves the unit. Ensure that this is
done in a curbed wash area where wash
water is captured and properly handled.
To minimize PM emissions from all vehi-
cles, construct temporary roadways with
gravel or other coarse aggregate material to
reduce silt content and thus, dust generation.
In addition, consider regularly cleaning paved
roads and other travel surfaces of dust, mud,
and contaminated material.
In land application units, the entire appli-
cation surface is often covered with a soil-
waste mix. The most critical preventive con-
trol measure, therefore, involves minimizing
contact between the application surface and
waste delivery vehicles. If possible, allow only
dedicated application vehicles on the surface,
restricting delivery vehicles to a staging or
loading area where they deposit waste into
application vehicles or holding tanks. If deliv-
ery vehicles must enter the application area,
ensure that mud and waste are not tracked
out and deposited on roadways, where they
can dry and then be dispersed by wind or
passing vehicles.
2. Waste Placement and
Handling
PM emissions from waste placement and
handling activities are less likely if exposed
material has a high moisture content.
Therefore, consider wetting the waste prior to
loadout. Increasing the moisture content,
however, may not be suitable for all waste
streams, as water could cause an adverse
"Containerizing wastes provides highly effective control of PM emissions, but, due to the large volume of many
industrial waste streams, containerizing waste may not always be feasible.
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Protecting Air Quality—Protecting Air Quality
chemical reaction with some wastes or unac-
ceptably increase leachate production. To
reduce the need for water or suppressants,
cover or confine freshly exposed material. In
addition, consider increasing the moisture
content of the cover material.
It can also be useful to apply water to unit
surfaces after waste placement. Water is gen-
erally applied using a truck with a gravity or
pressure feed. Watering may or may not be
advisable depending on application intensity
and frequency, the potential for tracking of
contaminated material off site, and climatic
conditions. PM control efficiency generally
increases with application intensity and fre-
quency but also depends on activity levels,
climate, and initial surface conditions.
Infrequent or low-intensity water application
may provide little effective control, while too
frequent or high-intensity application may
increase leachate volume, straining leachate
collection systems and threatening ground
water and surface water. Addition of excess
water to bulk waste material or to unit sur-
faces also can reduce the structural integrity
of the landfill lifts, increase tracking of conta-
minated mud off site, and worsen odor.
These undesirable possibilities may have
long-term implications for the proper man-
agement of a unit. Before instituting a water-
ing program, therefore, ensure that addition
of water does not produce undesirable
impacts on ground- and surface-water quali-
ty. Consult with your state agency with
respect to these problems.
Chemical dust suppressants are an alterna-
tive to water application. The suppressants
are detergent-like surfactants that increase
the total number of droplets and allow parti-
cles to more easily penetrate the droplets,
increasing the total surface area and contact
potential. Adding a surfactant to a relatively
small quantity of water and mixing vigorous-
ly produces small-bubble, high-energy foam
in the 100 to 200 um size range. The foam
occupies very little liquid volume, and when
applied to the surface of the bulk material,
wets the fines more effectively than water.
When applied to a unit, suppressants cement
loose material into a more impervious surface
or form a surface which attracts and retains
moisture. Examples of chemical dust sup-
pressants are provided in Appendix IV . The
degree of control achieved is a function of
the application intensity and frequency and
the dilution ratio. Chemical dust suppres-
sants tend to require less frequent application
than water, reducing the potential for
leachate generation. Their efficiency varies,
depending on the same factors as water
application, as well as spray nozzle parame-
ters, but generally falls between 60 and 90
percent reduction in fugitive dust emissions.
Suppressant costs, however, can be high.
At land application units, if wastes contain
considerable moisture, PM can be suppressed
through application of more waste rather
than water or chemical suppressants. This
method, however, is only viable if it would
not cause an exceedence of a design waste
application rate or exceed the capacity of soil
and plants to assimilate waste.
At surface impoundments, the liquid
nature of the waste means PM is not a major
concern while the unit is operational.
Inactive or closed surface impoundments,
however, may emit PM during scraping or
bulldozing operations to remove residual
materials. The uppermost layer of the low
permeability soils, such as compacted clay,
which may be used to line a surface
impoundment, contains the highest contami-
nant concentrations. Paniculate emissions
from this uppermost layer, therefore, are the
chief contributor to contaminant emissions.
When removing residuals from active units,
ensure that equipment scrapes only the resid-
uals, avoiding the liner below.
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Protecting Air Quality—Protecting Air Quality
3. Wind Erosion
Wind erosion occurs when a dry surface is
exposed to the atmosphere. The effect is most
pronounced with bare surfaces of fine parti-
cles, such as silty soil; heavier or better
anchored material, such as stones or clumps
of vegetation, has limited erosion potential
and requires higher wind speeds before ero-
sion can begin.
Compacted clay and in-situ soil liners tend
to form crusts as their surfaces dry. Crusted
surfaces usually have little or no erosion
potential. Examine the crust thickness and
strength during site inspections. If the crust is
more than JA inch thick and does not crum-
ble easily, then the soil probably has almost
no erosion potential.
Wind fences or barriers are effective means
by which to control fugitive dust emissions
from open dust sources. The wind fence or
barrier reduces wind velocity and turbulence in
an area whose length is many times the height
of the fence. This allows settling of large parti-
cles and reduces emissions from the exposed
surface. It can also shelter materials handling
operations to reduce entrainment during load-
in and loadout. Wind fences or barriers can be
portable and either man-made structures or
vegetative barriers, such as trees. A number of
studies have attempted to determine the effec-
tiveness of wind fences or barriers for the con-
trol of windblown dust under field conditions.
Several of these studies have shown a decrease
in wind velocity, however, the degree of emis-
sions reduction varies significantly from study
to study depending on test conditions.
Other wind erosion control measures
include passive enclosures such as three-
sided bunkers for the storage of bulk materi-
als, storage silos for various types of aggregate
material, and open-ended buildings. Such
enclosures are most easily used with small,
temporary waste piles. At land application
units that use spray application, further wind
erosion control can be achieved simply by
not spraying waste on windy days.
Windblown PM emissions from a waste pile
depend on how frequently the pile is dis-
turbed, the moisture content of the waste, the
proportion of aggregate fines, and the height of
the pile. When fine-particle wastes are loaded
onto a waste pile, the potential for dust emis-
sions is at a maximum, as fine particles are eas-
ily disaggregated and picked up by wind. This
tends to occur when material is either added to
or removed from the pile or when the pile is
otherwise reshaped. On the other hand, when
the waste remains undisturbed for long periods
and is weathered, its potential for dust emis-
sions may be greatly reduced. This occurs
when moisture from precipitation and conden-
sation causes aggregation and cementation of
fine particles to the surface of larger particles,
and when vegetation grows on the pile, shield-
ing the surface and strengthening it with roots.
Finally, limiting height of the pile can reduce
PM emissions, as wind velocities generally
increase with distance from the ground.
B. VOC Emission Control
Techniques
If air modeling indicates that VOC emissions
are a concern, consider pollution prevention
and treatment options to reduce risk. There are
several control techniques you can use. Some
are applied before the waste is placed in the
unit, reducing emissions; others contain emis-
sions that occur after waste placement; still oth-
ers process the captured emissions.
1. Choosing a Site to Minimize
Airborne Emission Problems
Careful site choice can reduce VOC emis-
sions. Look for locations that are sheltered
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Protecting Air Quality—Protecting Air Quality
from wind by trees or other natural features.
Know the direction of prevailing winds and
determine whether the unit would be
upwind from existing and expected future
residences, businesses, or other population
centers. After a unit is sited, observe wind
direction during waste placement, and plan
or move work areas accordingly to reduce
airborne emission impacts on neighbors.
2. Pretreatment of Waste
Pretreating waste can remove organic com-
pounds and possibly eliminate the need for
further air emission controls. Organic
removal or pretreatment is feasible for a vari-
ety of wastes. These processes, which include
steam or air stripping, thin-film evaporation,
solvent extraction, and distillation, can some-
times remove essentially all of the highly
volatile compounds from your waste.
Removal of die volatiles near the point of
generation may obviate the need for controls
on your subsequent process units and may
facilitate recycling the recovered organics
back to the process.
The control efficiency of organic removal
depends on many factors, such as emissions
from die removal system, and the uncon-
trolled emissions from management units
before die removal device was installed.
Generally, overall organic removal efficiencies
of 98 to over 99 percent can be achieved.
3. Enclosure of Units
You may be able to control VOC emissions
from your landfill or waste pile by installing
a flexible membrane cover, enclosing the unit
in a rigid structure, or using an air-supported
structure. Fans maintain positive pressure to
inflate an air-supported structure. Some of
the air-supported covers that have been used
consist of PVC-coated polyester with a
polyvinyl fluoride film backing. The efficien-
cy of air-supported structures depends pri-
marily on how well the structure prevents
leaks and how quickly any leaks that do
occur are detected. For effective control, the
air vented from the structure should be sent
to a control device, such as a carbon adsor-
ber. Consider worker safety issues related to
access to the interior of any flexible mem-
brane cover or other pollutant concentration
system.
Wind fences or barriers may also aid in
reducing organic emissions by reducing air
mixing on the leeward side of the screen. In
addition, wind fences reduce soil moisture
loss due to wind, which may in turn result in
decreased VOC emissions.
Floating membrane covers provide control
on various types of surface impoundments,
including water reservoirs in the western
United States. For successful control of organic
compounds, the membrane must provide a
seal at the edge of the impoundment and rain-
water must be removed. If gas is generated
under the cover, vents and a control device
may also be needed. Emission control depends
primarily on the type of membrane, its thick-
ness, and the nature of the organic compounds
in the waste. One study tracked a membrane
cover made of 100-mil high-density polyethyl-
ene extended over a concrete ring wall that
extended above grade level around the perime-
ter of the impoundment, and covered with
backfill to anchor and seal it. Theoretical esti-
mates based on diffusion through the mem-
brane indicate control efficiencies of 50 to 95
percent. Again, consult with your state or local
air quality agency to identify the most appro-
priate emission control for your impoundment.
4. Treatment of Captured
VOCs
In some cases, waste will still emit some
VOCs despite waste reduction or pretreatment
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Protecting Air Quality—Protecting Air Quality
efforts. Enclosing the unit serves to prevent the
immediate escape of these VOCs to the atmos-
phere. To avoid eventually releasing VOCs
through an enclosure's ventilation system, a
treatment system is necessary. We discuss some
of the better-known treatment methods below;
others also may be available.
a. Adsorption
Adsorption is the adherence of particles of
one substance, in this case VOCs, to the sur-
face of another substance, in this case a filtra-
tion or treatment matrix. The matrix can be
replaced or flushed when its surface becomes
saturated with the collected VOCs.
Carbon Adsorption. In carbon adsorption,
organics are selectively collected on the sur-
face of a porous solid. Activated carbon is a
common adsorbent because of its high inter-
nal surface area: 1 gram of carbon can have a
surface area equal to that of a football field
and can typically adsorb up to half its weight
in organics. For adsorption to be effective,
replace, regenerate, or recharge the carbon
when treatment efficiency begins to decline.
In addition, any emissions from the disposal
or regeneration of the carbon should be con-
trolled. Control efficiencies of 97 to 99 per-
cent have been demonstrated for carbon
adsorbers in many applications.
Biofiltration. While covering odorous
materials with soil is a longstanding odor
control practice, the commercial use of biofil-
tration is a relatively recent development.
Biofilters reproduce and improve upon the
soil cover concept used in landfills. In a
biofilter, gas emissions containing biodegrad-
able VOCs pass through a bed packed with
damp, porous organic particles. The biologi-
cally active filter bed then adsorbs the volatile
organic compounds. Microorganisms attached
to the wetted filter material aerobically
degrade the adsorbed chemical compounds.
Biofiltration may be a highly effective and
low-cost alternative to other, more conven-
tional, air pollution control technologies such
as thermal oxidation, catalytic incineration,
condensation, carbon adsorption, and
absorption. Successful commercial biofilter
applications include treatment of gas emis-
sions from composting operations, rendering
plants, food and tobacco processing, chemical
manufacturing, foundries, and other industri-
al facilities.18
b. Condensation
Condensers work by cooling the vented
vapors to their dew point and removing the
organics as liquids. The efficiency of a con-
denser is determined by the vapor phase con-
centration of the specific organics and the
condenser temperature. Two common types
of condensers are contact condensers and
surface condensers.
c. Absorption
In absorption, the organics in the vent gas
dissolve in a liquid. The contact between the
absorbing liquid and the vent gas is accom-
plished in spray towers, scrubbers, or packed
or plate columns. Some common solvents
that may be useful for volatile organics
include water, mineral oils, or other non-
volatile petroleum oils. Absorption efficien-
cies of 60 to 96 percent have been reported
for organics. The material removed from the
absorber may present a disposal or separation
problem. For example, organics must be
removed from the water or nonvolatile oil
without losing them as emissions during the
solvent recovery or treatment process.
d. Vapor Combustion
Vapor combustion is another control tech-
nique for vented vapors. The destruction of
18Mycock, J.C., J.D. McKenna, and L. Theodore. 1995. Handbook of Air Pollution Control Engineering and
Technology.
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Protecting Air Quality—Protecting Air Quality
organics can be accomplished in flares; thermal
oxidizers, such as incinerators, boilers, or
process heaters; and in catalytic oxidizers.
Flares are an open combustion process in
which oxygen is supplied by the air surround-
ing the flame. Flares are either operated at
ground level or elevated. Properly operated
flares can achieve destruction efficiencies of at
least 98 percent. Thermal vapor incinerators
can also achieve destruction efficiencies of at
least 98 percent with adequately high tempera-
ture, good mixing, sufficient oxygen, and an
adequate residence time. Catalytic incinerators
provide oxidation at temperatures lower than
those required by thermal incinerators. Design
considerations are important because the cata-
lyst may be adversely affected by high tempera-
tures, high concentrations of organics, fouling
from paniculate matter or polymers, and deac-
tivation by halogens or certain metals.
5. Special Considerations for
Land Application Units
Since spraying wastes increases contact
between waste and air, promoting VOC emis-
sions, you may want to choose another appli-
cation method, such as subsurface injection,
if the waste contains volatile organics. During
subsurface injection, waste is supplied to the
injection unit directly from a remote holding
tank and injected approximately 6 inches
into the soil; hence, the waste is not exposed
to the atmosphere. In addition, consider pre-
treating the waste to remove the organics
before placing it in the land application unit.
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Protecting Air Quality—Protecting Air Quality
Protecting Air Quality Action Items
Consider the following issues when evaluating and controlling air emissions from nonhaz-
ardous industrial waste management units:
Q Understand air pollution laws and regulations, and determine whether and how they
apply to a unit.
Q Evaluate waste management units to identify possible sources of volatile organic
emissions.
D Work with your state agency to evaluate and implement appropriate emission control
techniques, as necessary.
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Protecting Air Quality—Protecting Air Quality
Resources
American Conference of Governmental Industrial Hygienists. 1997. Threshold Limit Values for Chemical
Substances and Physical Agents and Biological Exposure Indices.
Christensen, T.H., R. Cossu, and R. Stegmann. 1995. Siting, Lining Drainage & Landfill Mechanics,
Proceeding from Sardinia 95 Fifth International Landfill Symposium, Volume II.
Finn, L., and R. Spencer. 1987. Managing Biofilters for Consistent Odor and VOC Treatment. BioCycle.
January.
Hazardous Waste Treatment, Storage and Disposal Facilities and Hazardous Waste Generators; Organic Air
Emission Standards for Tanks, Surface Impoundments, and Containers; Final Rule. Federal Register.
Volume 59, Number 233, December 6, 1994. pp. 62896 - 62953.
Mycock, J.C., J.D. McKenna, and L. Theodore. 1995. Handbook of Air Pollution Control Engineering and
Technology.
National Ambient Air Quality Standards for Paniculate Matter. Federal Register. Volume 62, Number 138,
July 18, 1997. pp. 38651 - 38701.
Orlemann, J.A., TJ. Kalman, J.A. Cummings, E.Y. Lin. 1983. Fugitive Dust Control Technology.
Robinson, W 1986. The Solid Waste Handbook: A Practical Guide.
Texas Center for Policy Studies. 1995. Texas Environmental Almanac, Chapter 6, Air Quality.
U.S. EPA. 1998. Taking Toxics Out of the Air: Progress in Setting "Maximum Achievable Control Technology"
Standards Under the Clean Air Act. EPA451/K-98-001. ;
U.S. EPA. 1997. Best Management Practices (BMPs) for Soil Treatment Technologies: Suggested Operational
Guidelines to Prevent Cross-media Transfer of Contaminants During Clean~up_Activities. EPA530-R-97-007.
U.S. EPA. 1996. Test Methods for Evaluating Solid Waste Physical/chemical Methods—SW846. Third
Edition.
U.S. EPA. 1995. Survey of Control Technologies for Low Concentration Organic Vapor Gas Streams.
EPA456-R-95-003.
U.S. EPA. 1995. User's Guide for the Industrial Source Complex (ISC3) Dispersion Models: Volume I.
EPA454/B-95-003a.
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Protecting Air Quality—Protecting Air Quality
Resources (cont)
U.S. EPA. 1995. User's Guide for the Industrial Source Complex (ISC3) Dispersion Models: Volume II-
Description of Model Algorithms. EPA454/B-95-003b.
U.S. EPA. 1994. Air Emissions Models for Waste and Wastewater. EPA453/R-94-080A.
U.S. EPA. 1994. Handbook: Control Techniques for Fugitive VOC Emissions from Chemical Process
Facilities. EPA625-R-93-005.
U.S. EPA. 1994. Toxic Modeling System Short-Term (TOXST) User's Guide: Volume I. EPA454/R-94-
058A.
U.S. EPA. 1992. Control of Air Emissions from Superfund Sites. EPA625-R-92-012.
U.S. EPA. 1992. Protocol for Determining the Best Performing Model. EPA454/R-92-025.
U.S. EPA. 1992. Seminar Publication: Organic Air Emissions from Waste Management Facilities.
EPA625-R-92-003.
U.S. EPA. 1991. Control Technologies for Hazardous Air Pollutants. EPA625-6-91-014.
U.S. EPA. 1989. Hazardous Waste TSDF—Fugitive Particulate Matter Air Emissions Guidance Document.
EPA450-3-89-019.
U.S. EPA. 1988. Compilation of Air Pollution Emission Factors. AP-42.
Viessman, W, and M. Hammer. 1985. Water Supply and Pollution Control.
5-35
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Part3
Protecting Surface Water
Chapter 6
Protecting Surface Water
-------
Contents
I, Federal Surface-Water Protection Programs 6-2
II. Overview of Storm-Water Protection Systems 6-4
III. Best Management Practices for Waste Managment Units 6-5
A. Baseline BMPs 6-6
B. Activity-Specific BMPs 6-7
C. Site-Specific BMPs '• 6-8
1. Flow Diversion Practices 6-8
a. Storm-water Conveyances (Channels, Gutters, Drains, and Sewers) 6-8
b. Diversion Dikes '• 6-8
2. Fjcposure Minimization Practices 6-9
a. Curbing and Diking 6-9
b. Covering 6-9
3. Sediment and Erosion Prevention Practices ..6-10
a. Vegetation • 6-10
b. Interceptor Dikes and Swales 6-11
c. Pipe Slope Drains f 6-11
d. Silt Fences, Straw Bales, and Brush Barriers ..6-11
e. Storm Drain Inlet Protection 6-12
f. Collection and Sedimentation Basins ' ..6-13
g. Check Dams : ...6-14
h. Terraces and Benches 6-14
i. Outlet Protection 6-14
4. Infiltration Practices 6-15
a. Vegetated Filter Strips and Grassed Swales 6-15
b. Infiltration Trenches 6-15
5. Other Prevention Practices 6-15
a. Preventive Monitoring 6-16
b. Dust Control , 6-16
c. Vehicle Washing • 6-17
6. Mitigation Practices • 6-17
a. Discharges to Wetlands ; 6-17
IV Methods of Calculating Run-on and Run-off Rates i 6-17
Action Items for Protecting Surface Water 6-20
Resources r "-^l
-------
Table of Contents
Figures:
Figure 1. BMP Identification and Selection Flow Chart 6-6
Figure 2. Coverings 6-9
Figure 3. Silt Fence 6-12
Figure 4. Straw Bale 6-12
Figure 5. Storm Drain Inlet Protection 6-13
Figure 6. Collection and Sedimentation Basins 6-14
Figure 7. Outlet Protection 6-15
Figure 8. Infiltration Trench 6-16
Figure 9. Typical Intensity-Duration-Frequency Curves 6-19
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Protecting Surface Water—Protecting Surface Water
Protecting Surface Water
Protect surface waters by limiting the discharge of pollutants into
the waters of the United States. Guard against inappropriate dis-
charges of pollutants associated with process wastewaters and
storm water to ensure the safety of the nation's surface waters.
Reduce storm water discharges by complying with regulations,
implementing available storm water controls, and identifying best
management practices (BMPs) to control storm water.
Over 70 percent of the Earth's sur-
face is water. Of all the Earth's
water, 97 percent is found in the
oceans and seas, while three per-
cent is fresh water. This fresh
water is found in glaciers, lakes, ground water,
and rivers. Water offers many valuable uses to
individuals and communities. Water is neces-
sary for recreational needs, drinking water
demands, fishing, commerce, agriculture, and
the overall quality of life.
This chapter will help address the
following questions: .
• What are the objectives of run-on and
run-off control systems?
• What should be considered in designing
surface-water protection systems?
• What are the appropriate BMPs to
address pollutant sources?
• What are some of the engineering and
physical mechanisms available to control
storm water?
With water being such a valuable com-
modity, the protection of our surface waters
should be everyone's goal. This goal can be
achieved by everyone focusing on improving
the quality of our surface waters.
Improvements in the quality of our surface
waters can be achieved by the continued pro-
tection against the discharge of pollutants.
Pollutants associated with process waste-
waters and storm waters need to be con-
trolled.
This chapter summarizes the existing fed-
eral surface-water protection programs. The
majority of this chapter then discusses meth-
ods that can be used to eliminate pollutant
discharges into surface waters associated with
storm-water management. Controlling storm-
water run-on and run-off from waste manage-
ment units minimizes contamination of sur-
face water. Use best management practices
(BMPs) in conjunction with engineering and
physical mechanisms to control storm water
and reduce or eliminate contaminant releases
to the environment.
6-1
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Protecting Surface Water—Protecting Surface Water
I. Federal Surface-
Water Protection
Programs
The federal Clean Water Act (CWA) gov-
erns the discharge of all pollutants into waters
of the United States, such as lakes, rivers,
streams, wetlands, ponds, or lagoons. It does
so primarily through a permitting process
known as the National Pollutant Discharge
Elimination System (NPDES). All entities that
discharge pollutants of any kind into waters of
the United States must have an NPDES per-
mit. Permits are issued for three types of
wastewaters: process wastewater, nonprocess
wastewater, and storm water. Permits typically
set forth specific "effluent limitations" relating
to the type of discharge. For process waste-
waters, the permit incorporates the more
stringent of industry-specific, technology-
based limitations, which can be found at 40
CFR Parts 405-471, or water quality-based
effluent limits (WQBELs).1 NPDES permits
also set forth monitoring and reporting
requirements. Some waste management units,
such as surface impoundments, may receive
an NPDES permit to discharge wastewaters
directly to surface waters. Other units may
need an NPDES permit only for storm-water
discharges. For industrial facilities that dis-
charge wastewaters to Publicly Owned
Treatment Works (POTW) through domestic
sewer lines, pretreatment of the wastewater
may be required. Under the National
Pretreatment Program, EPA, the state, and the
local regulatory agency establish discharge
limits to reduce the level of pollutants dis-
charged by industry into municipal sewer sys-
tems. These limits control pollutant levels
reaching a POTW, improving the quality of
the effluent and sludges produced by the
POTW. Protecting the POTW and improving
effluent and sludge quality significantly
increases the opportunity for beneficial reuse
of these end products. A fact sheet and fre-
quently asked questions on industrial pre-
treatment is included in the Appendix I for
this chapter, and are available on the Office of
Wastewater Management's web page at
.
As mentioned previously, some units may
be required to obtain an NPDES permit for
storm-water discharges. EPA has defined 11
categories under the definition of "storm
water associated with industrial activity" (40
CFR §122.26(b)(14)) that require an NPDES
storm-water permit for discharges to navigable
waters. These 11 categories consist of: (1)
facilities subject to storm-water effluent limita-
tions guidelines, new source performance
standards, or toxic pollutant effluent standards
under 40 CFR Part 129 (manufacturers of 6
specific pesticides); (2) "heavy" manufacturing
facilities; (3) mining and oil and gas opera-
tions with "contaminated" storm-water dis-
charges; (4) hazardous waste treatment, stor-
age, or disposal facilities; (5) landfills, land
application sites, and open dumps; (6) recy-
cling facilities; (7) steam electric generating
facilities; (8) transportation facilities; (9)
sewage treatment plants; (10) construction
operations disturbing five or more acres; and
(11) other industrial facilities where materials
are exposed to storm water. Nonhazardous
waste landfills and land application units
would fall under category 5.
Most surface impoundments that are
addressed by this guidance are part of an indus-
trial wastewater treatment process that results in
an NPDES-permitted discharge into surface
waters. The NPDES permit only sets pollution
limits for the final discharge of treated waste-
water. It does not establish any regulatory
requirements for design or operation of surface
impoundments that are part of the treatment
process such as liners and ground-water moni-
toring. Individual state environmental agencies,
under their own statutory authorities, may
^-Facilities that discharge wastewaters to publicly-owned treatment works (POTWs) may be subject to pretreatment
requirements found in 40 CFR Part 403.
6-2
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Protecting Surface Water—Protecting Surface Water
impose such requirements on surface
impoundment design and operation.
To provide flexibility for the regulated
community in acquiring storm-water dis-
charge permits, EPA has two NPDES permit
application options: individual permits and
general permits.2 Applications for individual
permits require the submission of a site
drainage map, a narrative description of the
site that identifies potential pollutant sources,
and quantitative testing data for specific para-
meters. General permit applications usually
involve the submission of a Notice of Intent
(NOI) that includes only general information,
not industry-specific or pollutant-specific
BMPs, and typically do not require collection
of monitoring data. NPDES general storm-
water permits require the development and
implementation of storm-water pollution pre-
vention plans and BMPs to limit pollutants in
storm-water discharges. EPA has issued the
Multi-Sector General Permit (60 Federal
Register 50803; September 29, 1995) which
covers 29 different industry sectors. The
Agency reviewed, on a sector-by-sector basis,
information concerning industrial activities,
BMPs, materials stored outdoors, and end-of-
pipe storm-water sampling data. Based on
this review, EPA identified pollutants of con-
cern in each industry sector, sources of these
pollutants, and BMPs used to control them.
The Multi-Sector General Permit requires the
submission of an NOI, development and
implementation of a site-specific pollution
prevention plan as the basic storm-water con-
trol strategy for each industry sector.
Sometimes it may be appropriate to "pre-
treat" the storm water before discharging it
into municipal separate storm sewer systems.
Using proven pollution control technologies,
practices that promote reuse and recycling of
material, and wastewater treatment, pollu-
tants from storm water can be reduced or
eliminated before it is discharged. NPDES
permits for "storm-water discharges associat-
ed with industrial activity" (as previously
defined) are issued by EPA or states with
NPDES permitting authority. If located in a
state with NPDES authority, contact the state
directly to determine the requirements for
storm water discharges. EPA's Office of
Wastewater Management's web page contains
a complete, updated list of the states with
approved NPDES permit programs, as well as
fact sheets and frequently asked questions on
the NPDES permit program. These facts
sheets can be found at
, and are
included in the Appendix III for this chapter .
If a state does not have NPDES permitting
authority, follow any state requirements for
storm-water discharges and contact EPA to
determine applicable federal requirements for
storm-water discharges.
If a waste management unit is subject to
federal or state storm-water discharge
requirements, use this chapter as an aid in
complying with applicable storm-water
Is a permit needed? :
To answer questions about whether or not
' a-facility needs to seekpermit coverage, or
to determine whether a particular program
; is administered by EPA or a state agency,
contact the state or EPA regional storm
water official listed in the Appendix II:
Currently, 42 states and the U.S. Virgin
Islands have federally approved state
NPDES permit programs. The following
8 states do not have final EPA approval:
: Alaska, Arizona, Idaho, Maine,
/Massachusetts, New Hampshire^ New
Mexico and Texas.
initially a group application procedure was available for facilities with similar activities to jointly submit a sin-
gle application for permit coverage. A multi-sector general permit was then developed based upon information
provided in the group applications. The group application option was only for use in the initial stages of the
program and is no longer available.
6-3
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Protecting Surface Water—Protecting Surface Water
discharge requirements and maintaining
appropriate surface-water controls. If a unit is
not subject to federal or state storm-water dis-
charge requirements, use this information to
proactively develop surface-water protection
systems.
II. Overview of
Storm-Water
Protection
Systems
Protecting surface water entails preventing
storm-water contamination during both unit
construction and the operational life of the
waste management unit. The primary run-off
contaminant during construction is sediment
eroded from exposed soil surfaces. Temporary
sediment and erosion control measures, such
as silt fences around construction perimeters,
straw bales around storm-water inlets, and
seeding or straw covering of exposed slopes,
are typically used to limit and manage erosion.
States or localities often require the use of sed-
iment and erosion controls at any construction
site disturbing greater than a certain number
of acres, and may have additional require-
ments in especially sensitive watersheds.
Consult with the state and local regulatory
agency to determine sediment and erosion
control requirements for construction.
Once a waste management unit has been
constructed, permanent run-on and run-off
controls are necessary to protect surface water.
Run-on controls are designed to prevent storm
water from entering active areas of units. If
run-on is not prevented from entering active
areas, it may seep into the waste and increase
the amount of leachate that must be managed.
It can also deposit contaminants from nearby
sites, such as pesticide from adjoining farms,
further burdening treatment systems.
Excessive run-on may also damage earthen
containment systems, such as covers and
berms. Run-on that contacts the waste may
carry contaminants into receiving waters
through surface-water run-off or into ground
What is "run-on"?
Run-on is a term used to refer to water
from outside a waste management unit that
flows toward the unit. Run-on encompass-
es storm water from rainfall or the melting
of snow or ice that falls directly on the unit
as well as the water that drains from
adjoining areas.
Why are run-on controls necessary?
Run-on controls are designed to prevent
(1) contamination of storm water, (2) ero-
sion that may damage the physical struc-
ture of units, (3) the surface discharge of
waste constituents, (4) the creation of
leachate, and (5) already contaminated sur-
face water from entering the unit.
What is "run-off1?
Run-off is a term used to refer to water or
leachate that drains or flows over land from
any part of a waste management unit. Run-
off can be created by rainfall, or the melt-
ing of snow and ice.
What is the purpose of a "run-off" control
system?
Run-off control systems are designed to
collect and control at least the water flow
resulting from a storm event of a specified
duration, such as a 24-hour, 25 year storm
event.
6-4
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Protecting Surface Water—Protecting Surface Water
water through infiltration. The Multi-Sector
General Permit does not authorize discharges
of leachate, which includes storm water
which contacts waste. The discharge of
leachate would be regulated under either an
individually drafted NPDES permit with site-
specific discharge limitations, or an alterna-
tive NPDES general permit if one is available.
Divert run-on by taking advantage of natural
contours or by constructing ditches or berms
designed to intercept and drain storm water.
Run-on diversion systems should be designed
to handle the peak discharge of a design
storm event, such as a 25-year storm. (See
Section IV for more information about design
storm events.)
Run-off controls channel, divert, and con-
vey storm water to treatment facilities, if
appropriate, and to intended discharge
points. Manage run-off from a waste manage-
ment unit as a potentially contaminated
material. Due to the potential for contamina-
tion, manage contact run-off from active areas
of a landfill or waste pile as leachate. Design
the leachate collection and removal systems
to handle such run-off, as well as any
leachate generated. Segregate noncontact run-
off to reduce the volume that may need to be
handled as leachate. Design surface impound-
ments with sufficient freeboard and adequate
capacity to accommodate not only waste but
also precipitation. For land application sites,
run-off from the application site may adverse-
ly affect nearby surface waters.
III. Best
Management
Practices for
Waste
Management
Units
Evaluation of BMPs should be considered in
both the design and operation of a waste man-
agement unit. Before identifying and imple-
menting BMPs, assess potential sources of
storm-water contamination. Two of the most
common sources of contamination from waste
management units are erosion and sediment
discharges caused by storm events. To conduct
a thorough assessment, create a map of the
waste management unit area, review operating
practices, and consider the design of the waste
management unit. Designing a surface-water
management system requires a knowledge of
local precipitation patterns, surrounding topo-
graphic features, and geologic conditions. After
a unit is in place, consider sampling run-off to
ascertain the quantity and concentration of
pollutants currently being discharged. (Refer to
the chapter on monitoring performance for
more information.) Collecting this information
may help select the most appropriate BMPs to
prevent or control pollutant discharges. Figure
1 illustrates the process of identifying and
selecting the most appropriate BMPs.
After assessing the potential and existing
sources of storm water contamination, the
What are BMPs?
BMPs are measures used to reduce or
eliminate contaminate releases to the envi-
ronment. They can take the form of a
process, activity, or physical structure.
6-5
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Protecting Surface Water—Protecting Surface Water
Figure 1. BMP Identification and Selection Flow Chart
Assessment Phase
Develop a site map
Inventory and describe exposed materials
List significant spills and leaks
Identify areas associated with industrial activity
Test for nonstorm-water discharges
Evaluate monitoring/sampling data if appropriate
(see monitoring performance chapter)
BMP Identification Phase
Operational BMPs
Source control BMPs
Erosion and sediment control BMPs
Treatment BMPs
Innovative BMPs
Implementation Phase
Implement BMPs
Train employess
Evaluation/Monitoring Phase
Conduct semiannual inspection/BMP evaluation
(see operating the waste management system chapter)
Conduct recordkeeping
Monitor surface water if appropriate
Review and revise plan
Adapted from U.S. EPA. 1992. Storm Water Management
for Industrial Activities: Developing Pollution Prevention
Plans and Best Management Practices. EPA832-R-92-006.
next step is to select appropriate BMPs to
address these pollutant contamination
sources. BMPs fall into three categories: base-
line, activity-specific, and site-specific.
A. Baseline BMPs
These practices are, for the most part,
inexpensive and relatively simple. They are
geared toward preventing situa-
tions that could lead to surface-
water contamination before they
occur. Many industrial facilities
already have these measures in
place for product loss preven-
tion, accident and fire preven-
tion, worker health and safety, or
compliance with other regula-
tions. (See the chapter on operat-
ing the waste management sys-
tem.) Baseline BMPs include the
following measures.
Good housekeeping. A clean
and orderly work environment is
an effective first step toward pre-
venting contamination of run-on
and run-off. Inventory materials
effectively and, if appropriate,
store them safely in areas pro-
tected from precipitation and
other water.
Preventive maintenance.
Expand existing facility mainte-
nance programs to include
inspection, upkeep, and repair or
replacement of surface-water
protection systems.
Visual inspections. Conduct
inspections of surface-water pro-
tection systems and waste man-
agement unit areas to discover
potential problems and identify
necessary changes. Areas to pay
particularly close attention to
include previous spill locations; material stor-
age, handling, and transfer areas; and waste
storage, treatment, and disposal areas.
Promptly rectify any situations, such as leaks
or spills, that could lead to surface-water con-
tamination.
Spill prevention and response. Establish
standard general operating practices for safe-
ty and spill prevention to reduce accidental
6-6
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Protecting Surface Water—Protecting Surface Water
releases that could contaminate run-on and
run-off. Devise spill response plans to pre-
vent any accidental releases from reaching
surface water.
Training employees to operate, inspect,
and maintain surface-water protection mea-
sures is itself considered a BMP, as is keeping
records of installation, inspection, mainte-
nance, and performance of surface-water
protection measures. For more information
on employee training and record keeping,
consult the chapter on operating the waste
management system.
B. Activity-Specific BMPs
After planning for baseline BMPs, consider
planning for activity-specific BMPs. In the
BMP manual for industrial facilities, Storm
Water Management for Industrial Activities:
Developing Pollution Prevention Plans and Best
Management Practices (EPA832-R-92-006),
EPA developed activity-specific BMPs for nine
industrial activities, including waste manage-
ment. The waste management BMPs are sum-
marized in this section. Like baseline BMPs,
these are often procedural rather than struc-
tural measures and, therefore, are often inex-
pensive and easy to implement.
Prevent waste leaks and dust emissions due to
vehicular travel. To prevent leaks, ensure that
trucks moving waste into and around a unit
have baffles (if they carry liquid waste) or
sealed gates, spill guards, or tarpaulin covers (if
the waste is solid or semisolid). To minimize
tracking dust off site where it can be picked up
by storm water, wash trucks in a curbed truck
wash area where wash water is captured and
properly handled. For more information on
these topics, consult the chapter on operating
the waste management system. Please be aware
that washwater from vehicle and equipment
cleaning is considered to be "process waste-
waters," and is not eligible for discharge under
EPA's Multi-Sector General Permit for industrial
storm water discharges. Such discharges would
require coverage under either an individually
drafted, site-specific NPDES permit, or an alter-
native NPDES general permit if one is available.
For land application, choose appropriate slopes.
Minimize run-off by designing a site with slopes
less than six percent. Moderate slopes help
reduce storm-water run-off velocity, which
encourages sedimentation and infiltration, and
reduces erosion. Storm-water discharges from
land application units are also regulated under
the Multi-Sector General Permit.
C. Site-Specific BMPs
In addition to baseline and activity-specific
BMPs, consider site-specific BMPs, which are
more advanced measures tailored to specific
pollutant sources at a particular waste man-
agement unit. These site-specific BMPs are
grouped into seven areas—flow diversion,
exposure minimization, sediment and erosion
prevention, infiltration, mitigation, wetlands,
and other prevention—for discussion below.
With many of the surface-water protection
techniques described in this section, it is
important to design for an appropriate storm
event. Generally, structures that control run-
on and run-off should be designed for the
discharge of a 24-hour, 25-year storm event.3
BMP Maintenance
Maintain these BMPs to ensure adequate
surface-water protection. Maintenance is
important because storms may damage
surface-water protection systems, such as
storage basin embarkments or spillways.
Run-off may also cause sediments to settle
in storage basins or ditches and carry float-
ables-r-tree branches, lumber, leaves, and
litter—to the basin. Facilties may need to
repair storm-water controls and periodical-
ly remove sediment and floatables.
^This discharge is the amount of water resulting from a 24-hour rainfall event of a magnitude with a 4 percent
statistical likelihood of occurring in any given year (i.e, once every 25 years). Such an event may not occur in
a given 25-year period, or may occur more than once during a single year.
6-7
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Protecting Surface Water—Protecting Surface-Water
When selecting and designing surface-water
protection systems, consult state, regional, and
local watershed management organizations.
Some of these organizations maintain manage-
ment plans devised at the overall watershed
level that address storm-water control. They
may be able to offer guidance in developing
surface-water protection systems for optimal
coordination with others in the watershed. As
a general guide, once a BMP has been imple-
mented, evaluate the effectiveness of the select-
ed BMPs from time to time.
1. Flow Diversion Practices
These measures are used to protect surface
water in two ways. First, they channel storm
water away from waste management units to
minimize contact of water with waste.
Second, they carry polluted or potentially
polluted materials to treatment facilities.
a. Storm-Water Conveyances
(Channels, Gutters, Drains,
and Sewers)
Storm-water conveyances, such as chan-
nels, gutters, drains, and sewers, may prevent
storm-water run-on from entering a waste
management unit or run-off from leaving a
unit untreated. Some run-on and run-off con-
veyances collect storm water and route it
around waste containment areas to prevent
contact with the waste, which might other-
wise contaminate storm water with pollu-
tants. Other conveyances collect water that
may have already come into contact with the
waste management unit and carry it to a
treatment plant (or possibly back to the unit
for reapplication in the case of land applica-
tion units). Conveyances should not mix the
stream of storm water diverted around the
unit with that of water that may have contact-
ed waste. Remember, storm water that con-
tacts waste is considered leachate and can
Conveyances can:
Direct storm-water flows around industri-
al areas, prevent temporary flooding,
require little maintenance, and provide
long-term control of storm-water flows.
Keep in mind:
Conveyances require routing through sta-
bilized structures to minimize erosion.
They also may increase flow rates, may be
impractical if there are space limitations,
and may not be economical.
only be discharged in accordance with an
NPDES permit other than the Multi-Sector
General Permit.
Storm-water conveyances may be con-
structed of or lined with materials such as
concrete, clay tile, asphalt, plastic, metal,
riprap, compacted soil, and vegetation. The
material used will vary depending on the use
of the conveyance and the expected intensity
of storm-water flow. Design storm-water con-
veyances with capacity to accept the estimat-
ed storm-water flow associated with the
selected design storm event. Section IV below
discusses methods for determining these
flows.
b. Diversion Dikes
Diversion dikes, often made with compact-
ed soil, direct run-on away from a waste ,
management unit. Dikes usually are built
uphill from a unit and work with a storm-
water conveyance to divert the water from the
unit. To minimize the potential for erosion,
diversion dikes are often constructed to redi-
rect run-off at a shallow slope to slow its
velocity. A similar means of flow diversion is
grading a site to keep storm water away from
waste handling areas, instead of or in
6-8
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Protecting Surface Water—Protecting Surface Water
Diversion dikes can:
Efectively limit storm-water flows over,;
industrial site areas; be installed at any-
time, be economical temporary structure
when built from soil onsite, and be con-
verted from temporary to permanent at
.any time: ; ^
Ifeepitimind: ^
Diversion dikes are not suitable for large :
drainage areas unless there is a gentle -:::
slope and may require maintenance after
heavyrainsJ- *•;; -I:';:';'" -."'...' .'.''•:
addition to using diversion dikes to redirect
water that would otherwise flow into these
areas. In planning for the installation of
dikes, consider the slope of the drainage area,
the height of the dike, the size of the flow it
will need to divert, and the type of con-
veyance that will be used with the dike.
2. Exposure Minimization
Practices
These measures, like flow diversion prac-
tices, reduce contact of water with waste.
They often are small structures immediately
surrounding a higher risk area, while flow
diversion practices may operate on the scale
of an entire waste management unit.
a. Curbing and Diking
These are raised borders enclosing areas
where liquid spills may occur. Such areas
could include waste transfer points in land
application, truck washes, and leachate man-
agement areas at landfills and waste piles.
The raised dikes or curbs prevent spilled liq-
uids from flowing to surface waters, enabling
prompt cleanup of only a small area.
b. Covering
Protect surface water by erecting a roof,
tarpaulin, or other permanent or temporary
covering (see Figure 2) over areas where
sources of surface-water contamination may
be located. Such areas could include the
active area of a landfill, transfer locations, and
stockpiles of daily cover. Combining covering
with other measures, such as curbing, can
prevent precipitation from falling directly on
materials and simultaneously prevent water
originating elsewhere from running on to the
materials.
If using temporary coverings, ensure that
sufficient weight is attached to prevent wind
from moving the cover, and repair or replace
the cover material if holes or leaks develop.
Figure 2. Coverings
Roof, overhang, or other permanent structure
Tarp or other permanent structure
From U.S. EPA. 1992. Storm Water Management for
Industrial Activities: Developing Pollution Prevention Plans
and Best Management Practices. EPA832-R-92-006.
6-9
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Protecting Surface Water—Protecting Surface Water
3. Sediment and Erosion
Prevention Practices
These practices serve to limit erosion (the
weathering of soil or rock particles from the
ground by wind, water, or human activity)
and to prevent particles that are eroded from
reaching surface waters as sediment. Erosion
and sedimentation can threaten aquatic life,
increase treatment costs for downstream
water treatment plants, and impede recre-
ational and navigational uses of waterways.
Erosion and sedimentation are of particular
concern at waste management units because
the sediment may be contaminated with
waste constituents and because erosion may
undercut or otherwise weaken waste contain-
ment structures. The following measures can
help limit erosion and sedimentation.
a. Vegetation
Reduce erosion and sedimentation by
ensuring that areas where water is likely to
flow are vegetated. Vegetation slows erosion
and sedimentation by shielding soil surfaces
from rainfall impacts, improving soil's water
storage capacity, holding soil in place, slow-
ing run-off, and enabling sediment to drop
out. One means of providing vegetation is to
preserve natural growth. This is achieved by
managing construction of the unit to mini-
mize disturbance of surrounding plants. If it
is not possible to leave all areas surrounding
a unit undisturbed, preserve strips of existing
vegetation as buffer zones in strategically cho-
sen areas of the site where erosion and sedi-
ment control is most needed, such as on
steep slopes and along stream banks. If it is
not possible to leave sufficient buffer zones of
existing vegetation, create buffer zones by
planting such areas with new vegetation.
Temporary or permanent seeding of erodi-
ble areas is another means of controlling ero-
sion and sedimentation using vegetation.
Permanent seeding, often of grass, is appro-
priate for establishing long-term ground
cover after construction and other land-dis-
turbing activities are cornplete. Temporary
seeding can help prevent erosion and sedi-
mentation in areas that' are exposed but will
not be disturbed again for a considerable
time. These areas include soil stockpiles, tem-
porary roadbanks, and dikes. Local regula-
tions may require temporary seeding of areas
that would otherwise remain exposed greater
than a certain length of time. Consult local
officials to determine whether such require-
ments apply. Seeding may not be feasible for
quickly establishing cover in arid climates or
during nongrowing seasons in other climates.
Sod, although more expensive, may be more
tolerant of these conditions than is seed and
may establish a denser grass cover more
quickly. Compost can also be used effectively
to establish vegetation on slopes.
Three other practices are often considered
along with vegetative measures. First, stream-
bank stabilization is the reinforcement of
stream banks with stones, concrete or asphalt,
logs, or gabions— structures formed from
crushed rock encased in wire mesh.
Stabilization is appropriate where stream flow
may be increased due to construction or other
unit activities and where vegetative measures
are not practical. Second, mulching, compost,
matting, and netting cover surfaces that are
steep, arid, or otherwise unsuitable for plant-
ing. These methods also can work in conjunc-
tion with planting to secure and protect seeds.
Mattings are sheets of mulch that are more sta-
ble than loose mulch chips. Netting is a mesh
of jute, wood fiber, plastic, paper, or cotton
that can hold mulch on the ground or stabilize
soils. These measures are sometimes used with
seeding to provide insulation, protect against
6-10
_
-------
Protecting Surface Water—Protecting Surface Water
birds, and hold seeds and soil in place. Third,
chemical stabilization—also known as chemi-
cal mulch, soil binder, or soil palliative—
involves spraying vinyl, asphalt, or rubber
onto soil surfaces to hold the soil in place and
protect against erosion. Erosion and sediment
control is immediate upon spraying and does
not depend on climate or season. Apply stabi-
lizer according to manufacturer's instructions
to ensure that water quality is not affected, and
avoid coating a large area with a thick layer of
stabilizer, which would create an impervious
surface and speed run-off to downgradient
areas.
b.
Interceptor Dikes and
Swales
Dikes, or ridges of compacted soil, and
swales, excavated depressions in which water
flows, work together to prevent entry of
run-on into erodible areas. A dike is built
across a slope upgradient of an area to be
protected, such as a waste management unit,
with a swale just above the dike. Water flows
down the slope, accumulates in the swale,
and is blocked from exiting it by the dike.
The swale is graded to direct water slowly
downhill across the slope to a stabilized out-
let structure. Since flows are concentrated in
the swale, it is important to vegetate the
swale to prevent erosion of its channel and
grade it so that predicted flows will not dam-
age vegetation.
c. Pipe Slope Drains
Pipe slope drains are flexible pipes or
hoses used to traverse a slope that is already
damaged or at high risk of erosion. They are
often used in conjunction with some means
of blocking water flow on the slope, such as a
dike. Water collects against the dike and is
then channeled to one point along the dike
where it enters the pipe, which conveys it
downhill to a stabilized (usually riprap-lined)
outlet area at the bottom of the slope. Ensure
that pipes are of adequate size to accommo-
date the design storm event and are kept
clear of clogs.
d. Silt Fences, Straw Bales,
and Brush Barriers
Silt fences (see Figure 3) and straw bales
(see Figure 4) are temporary measures
designed to capture sediment that has already
eroded and to reduce the velocity of storm
water. Silt fences and straw bales should not
be considered permanent measures. They
could be used, for example, during construc-
tion of a waste management unit or on a final
cover before permanent grass growth is estab-
lished. Silt fences consist of geotextile fabric
supported by wooden posts. These fences
slow the flow of water and retain sediment as
water filters through the geotextile fabric. If
properly installed, straw bales perform a simi-
lar function. Straw bales should be placed end
to end (with no gaps in between) in a shallow,
excavated trench and staked into place. Silt
fences and straw bales limit sediment entering
Silt fences, straw bales, and brush barriers
can:
Prevent downstream damage froHLsedi-
ment deposits and inexpensively ^prevent
eroded materials from reaching'surface
waters .••:.,.
Keep to mind:
These measures are not aproriate for
streams or; large swales and pose a risk
of washouts if improperly installed.
6-11
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Protecting Surface Water—Protecting Surface Water
Figure 3. Silt Fence
Extension of fabric and wire
into the trench
Bottom: Perspective of silt fence. Top: Cross-
section detail of base of silt fence.
From U.S. EPA. 1992. Storm Water Management
for Industrial Activities: Developing Pollution
Prevention Plans and Best Management
Practices. EPA832-R-006.
Figure 4. Straw Bale
From U.S. EPA. 1992. Storm Water Management
for Industrial Activities: Developing Pollution
Prevention Plans and Best Management
Practices. EPA832-R-006.
receiving waters. Both measures require fre-
quent inspection and maintenance, including
checking for channels eroded beneath the
fence or bales, removing accumulated sedi-
ment, and replacing damaged or deteriorated
sections.
Brush barriers work like silt fences and
straw bales but are constructed of readily avail-
able materials. They consist of brush and other
vegetative debris piled in a row and are often
covered with filter fabric to hold them in place
and increase sediment interception. Brush bar-
riers are inexpensive due to their reuse of mate-
rial that is likely available from clearing the site.
New vegetation often grows in the organic
material of a brush barrier, helping anchor the
barrier with roots. Depending on the material
used, it may be possible to leave a former
brush barrier in place and allow it to biode-
grade, rather than remove it.
e. Storm Drain Inlet
Protection
Filtering measures placed around any inlet
or drain to trap sediment are known as inlet
protection (see Figure 5). These measures pre-
vent sediment from entering inlets or drains
and possibly making their way to the receiving
waters into which the storm drainage system
discharges. Keeping sediment out of drainage
systems also serves to prevent clogging, loss of
capacity, and other problems associated with
siltation of drainage structures. Inlet protection
methods include sod, excavated areas for set-
tlement of sediment, straw bales or filter fence,
and gravel or stone with wire mesh. These
measures are appropriate for inlets draining
small areas where soil will be disturbed. Some
jurisdictions require installation of these mea-
sures before disturbance of more than a certain
acreage of land begins. Clean accumulated
sediment from inlet protection material fre-
quently to ensure continued operation.
6-12
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Protecting Surface Water—Protecting Surface Water
Figure 5. Storm Drain Inlet Protection
Excavated Gravel Inlet Protection
Sod Inlet Protection
<— Filter FaDric
Filter Fabric Inlet Protection
From U.S. EPA. 1992. Storm Water Management for Industrial Activities:
Developing Pollution Prevention Plans and Best Management Practices.
EPA832-R-006.
/. Collection and
Sedimentation Basins
A collection or sedimentation basin (see
Figure 6) is an area that retains run-off long
enough to allow most of the sediment to settle
out and accumulate on the bottom of the
basin. Since many pollutants are attached to
suspended solids, some other pollutants also
may settle out in the basin with the sediment.
The quantity of sediment removed will depend
on basin volume, inlet and outlet configura-
tion, basin depth and shape, and retention
time. Basins should be periodically dredged to
remove the accumulated sediment and regular-
ly maintained to minimize growth of aquatic
plants that can reduce their effectiveness. All
dredged materials, whether they are disposed
of or reused, should be managed appropriately.
Basins also may present a safety hazard.
Fences or other measures to prevent unwant-
ed public access to the basins and their asso-
ciated inlet and outlet '
structures are prudent
safety precautions.
In designing collection
or sedimentation basins (a
form of surface impound-
ment), consider storm-
water flow, sediment and
pollutant loadings, and
the characteristics of
expected pollutants. In
the case of certain pollu-
tants, it may be appropri-
ate to line the basins to
protect the ground water
below. Lining a basin with
concrete also facilitates
maintenance by allowing
dredging vehicles to drive
into a drained basin and
remove sediment. Poor
implementation of base-
line and activity-specific
BMPs may result in high sediment and pollu-
tant loads, leading to unusually frequent
dredging of settled materials. For this reason,
when operating sedimentation basins, ensure
that baseline and activity-specific BMPs are
first implemented to the fullest extent practi-
cable. Construction of these basins should be
Block and Gravel Inlet Protection
Sedimentation basins cam
Protect downstream areas against clogging
or damage, and contain smaller sediment
particles thanlsediment traps can due to
theirfonger detention time. .''•',
Keep in mind:
Sedimentation basins are generally not
suitable for. large areas, require regular
maintenance arid cleaning, and will not
remove very fine silts and clays unless
used with other measures
6-13
-------
Protecting Surface Water—Protecting Surface Water
Figure 6.
Collection and Sedimentation Basins
CMIETOI
tanrnqr
Deal* ml
Plan View
Minimi storige
Scil<»ent
suras* and
Fenuntnt p°ol
Crass Section AA1
From U.S. EPA. 1992. Storm Water Management
for Industrial Activitites: Developing Pollution
Prevention Plans and Best Management Practices.
EPA832-R-006.
supervised by a qualified engineer familiar
with state, regional or watershed, and local
storm-water requirements.
g. Check Dams
Small rock or log dams erected across a
ditch, swale, or channel can reduce the speed
of water flow in the conveyance. This reduces
erosion and also allows sediment to settle out
along the channel. Check dams are especially
useful in steep, fast-flowing swales where
vegetation cannot be established. For best
results, place check dams along the swale so
that the crest of each check dam is at the
same elevation as the toe (lowest point) of
the previous (upstream) check dam. Check
dams work best in conveyances draining
small areas and should be installed only in
manmade conveyances. Placement of check
dams in streams may require a permit and is
not recommended.
h. Terraces and
Benches
Terraces and benches are earthen embank-
ments with flat tops or ridge-and-channels.
Terraces and benches hold moisture and mini-
mize sediment loadings in run-off. They may
be used on land with no vegetation or where
it is anticipated that erosion will be a problem.
Terraces and benches reduce erosion damage
by capturing surface run-off and directing it
to a point where the run-off will not cause
erosion or damage. For best results, this point
should be a grassy waterway, vegetated area, or
tiled outlet. Terraces and benches should not
be constructed on sandy or rocky slopes.
What are some advantages of terraces and
benches?
Terraces and benches reduce run-off
speed and increase the distance of over-
land run-off flow. In addition, they hold
moisture better than do smooth slopes
and minimize sediment loading of surface
run-off.
What are some disadvantages of terraces
and benches?
Terraces and benches may significantly
increase cut and fill costs and cause
sloughing if excess water infiltrates the
soil. They are also not practical for sandy,
steep, or shallow soils.
/. Outlet Protection
Stone, riprap, pavement, or other stabi-
lized surfaces placed at a storm-water con-
veyance outlet are known as outlet-protection
(see Figure 7). Outlet protection reduces the
speed of concentrated storm-water flows exit-
ing the outlet, lessening erosion and scour of
6-14
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Protecting Surface Water—Protecting Surface Water
Figure 7. Outlet Protection
Pipe Outlet to Flat Area—
No Well-defined Channel
Section AA
Pipe Outlet to Well-defined
Channel
blanket
Plan
From U.S. EPA. 1992. Storm Water Management
for Industrial Activitites: Developing Pollution
Prevention Plans and Best Management Practices.
EPA832-R-006.
channels downstream. It also removes sedi-
ment by acting as a filter medium. Consider
installing outlet protection wherever predict-
ed outflow velocities may cause erosion.
4. Infiltration Practices
These measures encourage quick infiltra-
tion of storm-water run-off by preserving or
providing porous surfaces. Infiltration not
only reduces run-off velocity but also provides
some treatment of run-off, preserves natural
stream flow, and recharges ground water. In
many cases, these added functions are benefi-
cial, but they may make infiltration practices
inappropriate on unstable slopes, in cases
where run-off may be contaminated, or where
wells, foundations, or septic fields are nearby.
a. Vegetated Filter Strips and
Grassed Swales
Vegetated filter strips are gently sloped
areas of natural or planted vegetation. They
allow water to pass over them in sheetflow
(run-off that flows in a thin, even layer), infil-
trate the land, and drop sediment. Vegetated
filter strips are appropriate where soils are
well drained and the ground-water table is
well below the surface. They will not work
well on slopes of 15 percent or more due to
high run-off velocity. Strips should be at least
20 feet wide and 50 to 75 feet long in general,
and longer on steeper slopes. If possible, plan
to leave existing natural vegetation in place as
filter strips, rather than planting new vegeta-
tion, which will not function as well until it
becomes established.
Grassed swales function similarly to nonveg-
etated swales (see Sediment and Erosion
Control Practices above) except that grass
planted along the swale bottom and sides
will slow water flow and filter out sediment.
Permeable soil in which the swale is cut
encourages reduction of water volume through
infiltration. Check dams (see Sediment and
Erosion Control Practices above) are sometimes
provided in grassed swales to further slow run-
off velocity, increasing the rate of infiltration. To
optimize swale performance, use a soil which is
permeable but not excessively so; very sandy
soils may not hold vegetation well or may not
form a stable channel structure. Additionally,
grade the swale to a very gentle slope to maxi-
mize infiltration.
6-15
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Protecting Surface Water—Protecting Surface Water
b. Infiltration Trenches
An infiltration trench (see Figure 8) is a
long, narrow excavation ranging from 3 to 12
feet deep. It is filled with stone to allow for
temporary storage of storm water in the open
spaces between the stones. The water eventual-
ly infiltrates surrounding soil or is collected by
perforated pipes in the bottom of the trench
and conveyed to an outflow point. Such
trenches can remove fine sediments and solu-
ble pollutants. They should not be built in rel-
atively impervious soils, such as clay, that
would prevent water from draining from the
bottom of the trench; less than 3 feet above the
water table; in soil that is subject to deep frost
penetration; or at the foot of slopes steeper
than 5 percent. Infiltration trenches should not
be used to handle contaminated run-off. Run-
off can be pretreated using a grass buffer/filter
strip or treated in the trench with filter fabric.
Figure 8. Infiltration Trench
From U.S. EPA. 1992. Storm Water Management
for Industrial Activities: Developing Pollution
Prevention Plans and Best Management Practices.
EPA832-R-006.
5. Other Prevention
Practices
Prevention of surface-water contamination
can be accomplished by means other than
flow diversion, exposure minimization, sedi-
ment and erosion control, or infiltration.
Many of these practices are simple and inex-
pensive to implement.
a. Preventive Monitoring
This includes automatic monitoring and
control systems, monitoring of operations by
unit personnel, and testing of equipment.
These processes ensure that equipment func-
tions as designed and is in good repair, so
that spills and leaks, which could contami-
nate surface water, are minimized and do not
go undetected when they do occur. Some
automatic monitoring equipment, such as
pressure gauges coupled with pressure relief
devices, can correct problems without human
intervention, preventing leaks or spills that
could contaminate surface water if allowed to
occur. Other monitoring equipment may
provide early warning of problems so that
personnel can intervene before leaks or spills
occur. Systems that could contaminate sur-
face water if they failed and that could bene-
fit from automatic monitoring or early warn-
ing devices include leachate pumping and
treatment systems, liquid waste distribution
and storage systems at land application units,
and contaminated run-off conveyances.
b. Dust Control
In addition to being an airborne pollutant
itself, dust can be deposited as sediment in
run-off, threatening downstream surface
waters. Several methods of dust control are
available to prevent this. These include irri-
gation, chemical treatments, minimization of
exposed soil areas, wind breaks, tillage, and
sweeping. For further information on dust
control, consult the chapter on operating the
waste management system.
6-16
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Protecting Surface Water—Protecting Surface Water
c. Vehicle Washing
Materials that accumulate on tires and
other vehicle surfaces and then disperse
across a facility are an important source of
surface-water contamination. Vehicle wash-
ing removes materials such as dust and waste.
Washing stations can be located near waste
transfer areas or near the site exit.
Pressurized water spray is usually sufficient to
remove dust. Waste water from vehicle
washing operations should be contained and
handled appropriately. Discharge of such
waste water requires an NPDES permit other
than the Multi-Sector General Permit.
6. Mitigation Practices
These practices contain, clean up, or recover
spilled, leaked, or loose material before it can
reach surface water and cause contamination.
Other BMPs should be considered and imple-
mented to avoid releases, but procedures for
mitigation should be devised so that unit per-
sonnel can react quickly and effectively to any
releases that do occur. Mitigation practices
include simply sweeping or shoveling loose
waste into appropriate areas of the unit, vacu-
uming or pumping spilled materials into
appropriate treatment or handling systems,
cleaning up liquid waste or leachate using sor-
bents such as sawdust, or applying gelling
agents to prevent spilled liquid from flowing
towards surface water.
Constructed wetlands can:
Provide aesthetic as well as water quality
benefits and areas for wildlife habitat. :
Keepinmirid:
f method may be subject to multiple
federal, state and local regulations. In
^addition, constructed wetlands may not
be feasible if land is not available and may
notv,be effective: until time has been '-,'
allowed for; substantial plant growth. :
Constructed wetlands provide an alterna-
tive to natural wetlands. In this method, a
specially designed pond or basin, which is
lined in some cases, is stocked with wetland
plants that can manage pollutants through
biological uptake, microbial action, and other
mechanisms, as well as sedimentation. This
process often results in better pollutant
removal than would be expected from sedi-
mentation alone. When designing construct-
ed wetlands, consider that maintenance may
include dredging, similar to that required for
sedimentation basins; provisions for a dry-
weather flow to maintain the wetlands; mea-
sures to limit mosquito breeding; structures
to prevent escape of floating wetland plants
(such as water hyacinths) into downstream
areas where they are undesirable; and a pro-
gram of harvesting and replacing plants.
a. Discharges to Wetlands
Other methods of storm-water control are
available, such as discharge to constructed wet-
lands. These methods are less frequently used
and may involve more complicated designs.
The discharge of storm water into natural wet-
lands, or the modification of such wetlands to
improve their treatment capacity, may damage
a wetland ecosystem and, therefore, is subject
to federal, state, and local regulations.
IV. Methods of
Calculating Run-
on and Run-off
Rates
The design and operation of surface-water
protection systems will be driven by storm-
water flow. Calculate run-on and run-off
6-17
-------
Protecting Surface Water—Protecting Surface Water
flows for the chosen design storm event in
order to properly size controls and minimize
storm-water impacts. Controls based on too
small a design storm event, or sized without
calculating flows, may release contaminated
storm water. Similarly, systems can also be
designed for too large a flow, resulting in
unnecessary controls and excessive costs.
The usual approach for sizing surface-
water protection systems relies on the use of
standardized "design storms." A design storm
is, in theory, representative of many recorded
storms and reflects the intensity, volume, and
duration of a storm predicted to recur once
in a given number of years. In general, sur-
face--water protection structures should be
designed to handle the discharge from a 24-
hour, 25-year storm event—a rainfall event
of 24 hours duration and of such a magni-
tude that it has a 4 percent statistical likeli-
hood of occurring in any given year.
The Hydrometeorological Design Studies
Center (HDSC) at the National Weather
Service has prepared Technical Paper 40,
Rainfall Frequency Atlas of the United States for
Durations From 30 Minutes to 24 Hours and
Return Periods From 1 to 100 Years. This docu-
ment, published in 1961, contains rainfall
intensity information for the entire United
States. Another HDSC document, NOAA Adas
2, Precipitation Frequency Atlas of the Western
United States comes in 11 volumes, one for the
11 westernmost of the contiguous 48 states. It
was published in 1973. Precipitation frequen-
cy maps for the eleven western most states are
available on the Western Regional Climate
Center's web page at
< www.wrcc.55age.dri.edu/pcprifreq.html >, and
are included in Appendix IY HDSC is current-
ly assembling more recent data for some areas.
The state or local regulatory agency may be
able to provide data for the area.
Several methods are available to help
calculate storm-water flows. The Rational
Method (see sidebar) may be used for calcu-
lating run-off for areas of less than 200 acres.
Another potentially helpful tool for estimat-
ing storm flows is the Natural Resource
Conservation Service's TR-55 software.4
TR-55 estimates run-off volume from accu-
mulated rainfall and then applies the run-off
volume to a simplified hydrograph for peak
discharge total run-off estimations.
Rational Method for Calculating Storm-
Water Run-off Flow
where
Q = peak flow rate (run-off), in cubic feet
per second (cfs)*
c — run-off coefficient, unitless. The coef-
ficient c is not directly calculable,
so average values based on experience
are used. Values of c range from 0 (all
infiltration, no run-off) to 1 (all run-
off, no infiltration). For example, flat
lawns with sandy soil have c of 0.05
to 0.10, while concrete streets have c
of 0.80 to 095.
i = average rainfall intensity, in inches per
hour, for the time of concentration, tc,
which is a calculable flowtime from
the most distant point in the drainage
area to the point at which Q is being
calculated. Once tc is calculated and a
design storm event frequency selected,
i can be read from a graph such as
that shown in Figure 9.
a = drainage area, in acres. The drainage
area is the expanse in which all run-
off flows to the point at which Q is
being calculated.
* Examining the units of i and a would indicate that
Q should be in units of ac-in/hr. Since! ac-in/hr =
1.008 cfs, however, the units are interchangeable
with a negligible loss of accuracy, and units of cfs
are usually desired for subsequent calculations.
6-18
''''TR-55, Urban Hydrology for Small Watersheds Technical Release 55, presents simplified procedures to calcu-
late storm run-off volume, peak rate of discharge, hydrographs, and storage volumes required for floodwater
reservoirs. These procedures are applicable in small and especially urbanizing watersheds. TR-55 can be
downloaded from NRCS at .
-------
Protecting Surface Water—Protecting Surface Water
Computer models are available to aid in the
design of run-on and run-off control (see side-
bar). EPA's Storm Water Management Model
(SWMM) is a comprehensive model capable of
simulating the movement of precipitation and
pollutants from the ground surface through
pipe and channel networks, storage treatment
units, and finally to receiving water bodies.
Using SWMM, it may be possible to perform
both single-event and continuous simulation
on catchments having storm sewers and natur-
al drainage, for prediction of flows, stages, and'
pollutant concentrations.
Some models, including SWMM, were
developed for purposes of urban storm-water
control system design, so it is necessary to
ensure that their methodology is applicable to
design for industrial units. As with all com-
puter models, these should be used as part of
the array of design tools, rather than as a sub-
stitute for careful consideration of the unit's
design by qualified professionals.
Figure 9. Typical Intensity-Duration-
Frequency Curves
From WATER SUPPLY AND POLLUTION CON-
TROL, 5th Edition, by Warren Viessman, Jr. and
Mark J. Hammer; Copyright (©) 1993 by Harper
Collins College Publishers. Reprinted by permis-
sion of Addison-Wesley Educational Publishers.
BASINS: A Powerful Tool for Managing
Watersheds. A multi-purpose environmental '
analysis system that integrates a geographical
information system,(GIS), national watershed
data, and state-of-the-art environmental assess-
ment and modeling took into one convenient
package.
Storm Water'Management Model (SWMM).
Simulates the movement of precipitation and pol-
lutants from the ground surface dirough pipe and
channel networks, storage treatment units, and
receiving waters.
The Source Loading and Management Model
(SLAMM). Explores relationships between sources
of urban run-off pollutants and run-off quality. It
now includes a wide variety of source area and
outfall control practices. SLAMM is strongly based
on actual field-observations, with minimal
reliance'on theoretical processes that have not
been adequately documented or confirmed in the
field. SLAMM is'mdsdy used as a planning tool,
to better understand sources of urban run-off pol-
lutants and dieir control.
Simulation for Water Resources in Rural basins
(SWRRB). Simulates hydrologic, sedimentation,
and nutrient and pesticide transport in large,
complex rural watersheds. It can predict die effect
of management decisions on water, sediment, and
pesticide yield with seasonable accuracy for
ungauged rural basins throughout the United
States.
Pollutant Routing Model (P-ROUTE). Estimates
aqueous poEiitant concentrations on a reach by
reach flow basis; using 7Q10 or mean flow.:,
EnhanoSd Stiem Water Quality Model (QUAL2E).
Simulates the major reactions of nutrient cycles,
algalproduction^benthic and carbonaceous
demand, atmospheric reaeration and their effects
on the dissolved oxygen balance. It is intended as
a water quality planning tool for developing total
maximum daily loads (TMDLs) and can also be
used in conjunction with field sampling for identi-
fying the magnitude and quality charactersitics of
nonpoint sources ,
6-19
-------
I Pro
Protecting Surface Water—Protecting Surface Water
Action Items for Protecting Surface Water
Conduct the following activities when designing or operating a units surface-water protection
systems. i
Q Comply with applicable National Pollutant Discharge Elimination System (NPDES)
and state permitting requirements.
O Assess operating practices, potential pollutant sources, and surface-water flows to
determine the need for and type of storm-water controls.
D Implement baseline and activity-specific best management practices (BMPs), such as
good housekeeping practices and spill prevention and response plans.
Q Choose a design storm event, such as the 24-hour, 25-year event, and obtain precip-
itation intensity data for that event to size storm-water control devices.
Q Select and implement site-specific BMPs, such as diversion dikes, sedimentation
basins, and outlet protection.
Q Devise a system for inspecting and maintaining the chosen controls, possibly as part
of the operating plan.
6-20
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Protecting Surface Water—Protecting Surface Water
Resources
Florida Department of Environmental Regulation. No date. Storm water management: A guide for
Floridians.
Pitt, R. 1988. Source loading and management model: An urban nonpoint source water quality model
(SLAMM). University of Alabama at Birmingham.
McGhee, T. 1991. McGraw-Hill series in water resources and environmental engineering. 6th ed.
Urbonas, B., and P Stahre. 1993. Storm water: Best management practices and detention for water quality,
drainage, and CSO management. PTR Prentice Hall.
U.S. EPA. 1995. Process design manual: Land application of sewage sludge and domestic septage.
EPA625-R-95-001.
U.S. EPA. 1995. Process design manual: Surface disposal of sewage sludge and domestic septage.
EPA625-R-95-002.
U.S. EPA. 1995. NPDES Storm Water Multi-Sector General Permit information package.
U.S. EPA. 1995. Storm water discharges potentially addressed by phase II of the National Pollutant
Discharge Elimination System storm water program. .Report to Congress. EPA833-K-94-002.
U.S. EPA. 1994. Project summary: Potential groundwater contamination from intentional and non-intentional
storm water infiltration. EPA600-SR-94-061.
U.S. EPA. 1994. Storm water pollution abatement technologies. EPA 600-R-94-129.
U.S. EPA. 1993. Overview of the storm water program. EPA833-F-93-001.
U.S. EPA. 1993. NPDES storm water program: Question and answer document, volume 2.
EPA833-F093-002B.
U.S. EPA. 1992. An approach to improving decision making in wetland restoration and creation.
EPA600-R-92-150.
U.S. EPA. 1992. NPDES storm water program: Question and answer document, volume 1.
EPA833-F-93-002.
U.S. EPA. 1992. NPDES storm water sampling guidance document. EPA833-B-92-001.
6-21
-------
Protecting Surface Water—Protecting Surface Water
Resources (cent.)
U.S. EPA. 1992. Storm water general permits briefing. EPA833-E-93-001. ;
U.S. EPA. 1992. Storm water management for industrial activities: Developing pollution prevention plans
and best management practices. EPA832-R-92-006.
U.S. EPA. 1992. Storm water management for industrial activities: Developing pollution prevention plans
and best management practices. Summary guidance. EPA833-R-92-002.
Viessman Jr., W., and M.J. Hammer. 1985. Water supply and pollution control. ;4th ed.
Washington State Department of Ecology. 1993. Storm water pollution prevention planning for industrial
facilities: Guidance for developing pollution prevention plans and best management practices. Water qual-
ity report. WQ-R-93-015. September. ;
6-22
-------
Part IV
Protecting Ground Water
Chapter 7: Section A
Assessing Risk Section
-------
Contents
I. An Overview of the Approach in the Guide ; 7A-3
A. Assessing Risk 7A-3
1. The Approach to Liner Performance and Liner Assumptions in the Guide 7A-4
2. What We Know About Liners and Caps 7A-5
B. Request for Comments \ 7A-6
II. Identification of Contaminants 7A-7
A. Exposure Assessment: Understanding Fate and Transport 7A-9
B. Risk Characterization: The 3-Tiered Approach 7A-12
1. Tier 1: National Evaluation 7A-15
2. Tier 2: Lacation Adjusted Evaluation .: 7A-18
3. Tier 3: Site-Specific Ground-Water Fate and Transport Analysis : 7A-24
Action Items for Assessing Risks to Ground Water 7A-30
Resources - 7A-31
Tables:
Table 1: Earth's Water Resources : 7A-1
Table 2: List of Constituents with Maximum Contaminant Levels (MCLs) 7A-8
Table 3: Example National Evaluation Lookup Table for Landfills 7A-16
Table 4: Example National Evaluation Lookup Table Comparison Results ; 7A-17
Table 5: Example Site-Specific Parameters , 7A-21
Table 6: Example Site-Specific, Ground-Water Fate and Transport Models !. 7A-28
Figures: |
Figure 1: Representation of Fate and Transport Analysis 7A-10
Figure 2: Process Diagram: Use of National Evaluation Lookup Tables 7A-19
Figure 3: Example Input Screens for Tier 2 Model 7A-22
-------
Protecting Ground Water—-Assessing Risk Section
Assessing Risk
Protect ground water by assessing risk associated with the
waste management practices and tailoring management con-
trols accordingly. Use the three-tiered evaluation approach to
determine recommended liner systems and whether land appli-
cation is appropriate. Follow guidance on liner design and land
application practices.
round water
is the water
found in
the soil
and rock
that make up the Earth's
surface. Although it
comprises only about
0.69 percent of the
Earth's water resources,
ground water is of great
importance. It repre-
sents about 25 percent
of fresh water resources,
and, when the largely
inaccessible fresh water
in ice caps and glaciers
is discounted, ground
water is the Earth's largest fresh water
resource, far surpassing lakes and rivers (see
Table I).1 Statistics about use of ground water
as a drinking water source underscore the
importance of the resource. Ground water is a
source of drinking water for more than half of
the people in the United States.2 In rural
areas, 97 percent of households rely on
ground water as their primary source of
drinking water.
In addition to its importance for domestic
water supplies, ground water is heavily used
Table 1.
Earth's Water Resources
Resource • Percent of Percent of
Total Nonoceanic
Oceans
Ice caps and glaciers
Ground water and soil moisture
Lakes and Rivers
Atmosphere
Biosphere
97.25
2.05
0.685
0.0101
0.001
0.00004
—
74.65
24.94
0.37
0.036
0.0015
Adapted from Berner, E.K. and R. Berner. 1987. The Global Water
Cycle: Geochemistry and Environment
by industry and agriculture. It provides
approximately 37 percent of irrigation water
and about 18 percent of the water used by
industry.3 Ground water has other important
environmental functions as well, such as pro-
viding recharge to lakes, rivers, wetlands, and
estuaries.
Water beneath the ground surface occurs in
an upper unsaturated or vadose zone and a
deeper saturated zone. The unsaturated zone is
the area above the water table where the soil
pores are not filled with water, although some
1 Berner, E. K. and R. Berner. 1987. The Global Water Cycle: Geochemistry and Environment.
2Surface water, in the form of lakes and rivers, is the other major drinking water source. Speidel, D., L.
Ruedisili, and A. Agnew. 1988. Perspectives on Water: Uses and Abuses.
3 Excludes cooling water for steam-electric power plants. U.S. Geological Survey. 1998. Estimated Use of
Water in the United States in 1995. .
7A-1
-------
Protecting Ground Water—Assessing Risk Section
water may be present.4 The
subsurface area below the
water table where the pores
and cracks are filled with
water is called the saturated
zone. This chapter focuses
on ground water in the sat-
urated zone, from which
most ground-water with-
drawals are made.
Because ground water is
a major source of water for
drinking, irrigation, and
process water, the public,
industry, and federal, state,
and local governments are
all concerned about
ground-water contamina-
tion. There are many
threats to the quality of
ground water, such as infil-
tration of fertilizers and
pesticides, contamination
from faulty or overloaded
septic fields, and releases
from industrial facilities,
including waste manage-
ment units.
Because ground water
flows beneath the surface of
the earth, and moves very
slowly in many aquifers,
years may elapse before
contamination is discov-
ered and its sources identi-
fied. Once ground water
has been contaminated,
remedial action and moni-
toring can be costly, can require years of effort
or in some circumstances, might be technical-
ly infeasible. For these reasons, it is extremely
important to prevent ground-water contami-
nation if possible or minimize impacts by
implementing controls tailored to the risks
Ground Water in the Hydrologic Cyde
The hydrologic cycle involves the continuous movement of
water between the atmosphere, surface water, and the
ground. Ground water must be understood in relation to
both surface water and atmospheric moisture. Most addi-
tions (recharge) to ground water come from the atmosphere
in the form of precipitation, but surface water in streams,
rivers, and lakes will move into the ground-water system
wherever the hydraulic head of the water surface is higher
than the water table. Most water entering the ground as pre-
cipitation returns to the atmosphere, by evapotranspiration.
Most water that^reaches the saturated zone eventually
returns to the surface by flowing to points of discharge,
such as rivers, lakes, or springs. Soil, geology, and climate
will determine the amounts and rates of flow among the
atmospheric, surface, and ground-water systems.
associated with the waste. Natural subsurface
processes, such as biodegradation, sorption,
and precipitation, can attenuate compounds in
the ground water before they reach receptors.
1 U.S. EPA. 1989. Glossary of Environmental Terms and Acronym List.
7A-2
-------
Protecting Ground Water—Assessing Risk Section
I. An Overview of
the Approach in
the Guide
The guidance recommends tailoring pro-
tective liner systems to the wastes that are
managed in a unit and evaluating whether
land application of a waste is appropriate
using a three-tiered approach to ground-
water modeling and risk assessment. The
type of assessment you choose depends, in
part, on the complexity of a site and the char-
acteristics of the waste. All three tiers rely on
ground-water modeling to evaluate the
potential for ground-water contamination.
Each successive tier incorporates more site-
specific data to tailor recommendations to
your circumstances.
The modeling tool for Tiers 1 and 2 is the
EPA Industrial Waste Evaluation Model
(IWEM) incorporated into the CD ROM ver-
sion of this guidance. This is a stand-alone,
simple-to-use model that does not require
previous modeling experience. Tier 1
National Evaluation lookup tables can be
found in Appendix I.
Tier 1 - National Evaluation: Once you
know the concentrations of constituents in
a waste, generic tables provide design rec-
ommendations (liner system or waste
application concentrations). If the waste
contains several constituents, choose the
most protective design indicated for any of
the constituents. This tier of analysis is the
most conservative and will generally rec-
ommend more stringent controls. It is
designed to be more conservative because
it captures a wide range of site conditions
across the country.
Tier 2 - Location-Adjusted Evaluation: You
can enter data for up to seven of the most
sensitive waste and site-specific variables
to assess whether an alternative design will
be protective. This tier is generally less
conservative because it incorporates an
intermediate level of specificity in the data.
Tier 3 - Comprehensive Risk Assessment
This tier relies on a comprehensive analysis
of site characteristics to determine a design
that will be protective. Tier 3 uses substan-
tial amounts of site-specific data.
A. Assessing Risk
IWEM analyzes three liner scenarios over a
10,000 year time frame. The Tier 1 and 2 risk
evaluations work as follows. IWEM incorpo-
rates 191 constituents with toxicity reference
levels that are either drinking water maxi-
mum contaminant levels (MCLs) set under
the Safe Drinking Water Act or health-based
numbers (HBNs) derived from several
sources. First, we have identified a bench-
mark concentration (MCL or HBN) for each
constituent in a monitoring well associated
with a waste management unit. The goal is
not to exceed the benchmark concentrations
in the monitoring well. The model starts from
this benchmark concentration in the monitor-
ing well and back calculates the effects of
dilution and attenuation and release rate from
a unit to determine the leachate constituent
concentrations for wastes that can be protec-
tively managed in a particular unit design.
For land application, the model recommends
whether wastes can be protectively land
applied, based on leachate constituent con-
centrations. Finally, the model caps leachate
concentrations from an industrial solid waste
management unit at a level no higher than
1000 mg/1 for any single constituent, because
higher leachate concentrations are not expect-
ed from these waste management units. The
39 hazardous waste toxicity characteristic
constituents (TC) are capped at their TC lev-
7A-3
-------
Protecting Ground Water—Assessing Risk Section
els because concentrations above those levels
are hazardous waste.
The technical background document
accompanying the model thoroughly explains
the model, including the parameters that
have the greatest effect on modeling results.
The-sensitive parameters that a user can
input at Tier 2, in addition to waste charac-
teristics, are:
• Leakage rate,
• Surface area of the waste management
unit,
• Depth to water table,
• Distance to the well,
• Thickness of the aquifer,
• KOC (retardation rate for organic con-
stituents), and adjusted Kd for metals,
• A, (coefficient defining hydrolysis or
biodegradation rate).
One of the most sensitive parameters is
the leakage rate or the rate at which leachate
is released from a unit and moves into sub-
surface soils.-The leakage rate is influenced
by a number of factors. Some key factors are
the amount of precipitation, the level of liq-
uid in the unit (head), and the hydraulic
conductivity of the liner material. Hydraulic
conductivity refers to the capacity to transmit
fluid. Low hydraulic conductivity slows
leachate migration out of a unit. For synthet-
ic liners, the occurrence of tears, rips or holes
also influences leakage rate.
Units that rely only on natural soils under-
lying the unit, including units for direct land
application of waste, generally have higher
leakage rates. A single clay or synthetic liner
can reduce the leakage rate to some extent.
However, composite and double liners that
combine two or more layers of liner material
with leachate collection and leak detection
(for double liners) significantly increase the
effectiveness of the containment system in
minimizing leakage to the subsurface during
the period when the leachate collection sys-
tem is actively managed.
For a landfill that no longer receives waste
and for surface impoundments and waste
piles where waste remains in place at closure,
the cap that is placed over the unit becomes
an important component of the final contain-
ment system. One key purpose of the final
cap is to minimize infiltration of precipitation
which generates leachate that may eventually
leak into subsurface soils and migrate to
ground water. The liner system in the short
term, and the cap and the liner system
together in the long term, to a large extent
determine the leakage rate from the unit. The
leakage rate that is associated with various
unit designs is one of the most sensitive vari-
ables in ground-water risk modeling to evalu-
ate which liner system is protective for man-
aging particular wastes in a unit.
1. The Approach to Liner
Performance and Liner
Assumptions in the Guide
The guide recommends a comprehensive
approach to design, construction, operation
and long term care of a waste management
unit to minimize the potential for many of
these problems. This includes:
Recommending liner design based on
characteristics of waste managed in the
unit.
Strong emphasis on construction quality
assurance and control.
Emphasis on compatibility between the
liner and the waste .
Continuing operation and maintenance
practices to protect liner performance.
7A-4
-------
Protecting Ground Water—Assessing Risk Section
• Ground-water monitoring as an integral
component of a protective management
system, to assess liner performance.
• Corrective action to clean up releases.
• Closure with a cap that meets or exceeds
the design of the liner (infiltration
through the cap equal to or less than
leakage through the liner).
• Post closure care and monitoring to
maintain the cap for the time period nec-
essary to ensure the waste no longer
poses a risk to human health.
In addition, assumptions concerning liner
performance have a significant impact on the
modeling results. A brief summary of the
basis for leakage rate in the modeling sce-
nario for each liner type follows (these per-
formance levels remain constant for the
10,000 year time frame of the model):
No liner: In Tier 1, monte carlo analysis of
a range of leakage rates, based on water
balance and native soil type for nearest
meteorological station. In Tier 2, the
model can provide a regional infiltration
rate, based on user-specified location.
Single liner: consisting of three feet of
compacted clay with a hydraulic conduc-
tivity of 10'7 cm/s. In Tier 1, monte carlo
analysis of a range of infiltration rates,
based on water balance for nearest meteo-
rological station. In Tier 2, the model can
provide users with a regional infiltration
rate, based on user-specified location.
Composite liner the engineered system
includes leachate collection. Landfills are
assumed to have a constant hydraulic head
of no more than 12 inches. The leakage
rate, in Tier 1, is a single value calculated
using an equation developed by Bonaparte
et al5, assuming one .005 in.2 hole per acre.
For landfills, the leakage rate is 0.1 g/a/d
and for surface impoundments, 0.9 g/a/d
This represents a well designed and
installed liner.
2. What We Know About Liners
and Caps
In general, we have learned much over the
past 20 years about the performance of liner
systems and caps, and there have been many
improvements in construction, installation,
and quality assurance and control proce-
dures. However, we recognize that there is
still uncertainty associated with liner perfor-
mance, in the near term as well as in the long
term. While some studies indicate that engi-
neering properties of liners may last for hun-
dreds of years, there are a variety of factors
that may influence longevity and perfor-
mance, such as poor construction, installation
or facility operation, or geologic movement
below the liner that can cause holes, tears or
larger failures. Some defects are likely to have
little to moderate effect on the leakage rate.
Other defects may have a significant effect
and even necessitate corrective action.
We have conducted some preliminary sen-
sitivity analyses to compare leakage rates
from a variety of theoretical composite liner
scenarios. Scenarios varied the size of holes
and tears and the number per acre; contact
between the synthetic and the clay layer; the
conductivity of the underlying clay layer; and
the head of liquid on top of the synthetic
liner. Results of these preliminary analyses
provided a range of leakage rates ranging
from 1.5E-08 m/year to an unrealistically
high 353 m/year. As a comparison, the leak-
age rate used in our composite liner scenario
is 3.3E-05 m/yr (landfills). These results indi-
cate several key areas to pursue further analy-
ses. 1) What empirical data are available con-
cerning liner defects at the time of installa-
tion; and what data are available concerning
actual leakage rates at operating industrial
' Bonaparte, R., Giraud, J.R, and Gross, B.A. 1989. "Rates of Leakage Through Landfill Liners,"
Proceedings of Geosynthetic '89 Conference, Volume 1.
7A-5
-------
Protecting Ground Water—Assessing Risk Section
waste units to serve as a basis for identifying
reasonable performance scenarios? 2) We cal-
culate the leakage rate for our modeling sce-
nario using the equation cited above (and dis-
cussed in the IWEM Technical Background
Document). We are looking for information on
the validity of the equation over a wide range
of conditions. 3) If we were to model a range
of infiltration rates for composite liners, what
is a reasonable range to include in the analy-
sis? (A more thorough discussion of the sensi-
tivity analyses is in the IWEM Technical
Background Document, contained on the CD
ROM and available in the docket.)
Another area of uncertainty is the fate of
constituents within a unit. Over time, a number
of degradation processes may be under way
that reduce the hazards associated with some
constituents. On the other hand, a landfill with
an intact cover may be reasonably dry and thus
degradation may be quite slow (also reducing
leachate generation). Other toxic constituents,
such as heavy metals, will not degrade.
Covers present continuing engineering
challenges over time, because they are more
susceptible to factors such as freezing and
thawing, wetting and drying, temperature
fluctuations, root infiltration, and subsidence.
Covers are, however, not subject to chemical
attack from waste constituents, nor are they
subject to the same stresses from waste place-
ment as a bottom liner. Also, final covers are
simpler to repair, which would help control
the risk of infiltration into the landfill, assum-
ing there is an active program to monitor or
periodically replace the cover. Unless the final
cover is regularly repaired or replaced, the
bottom liner could outlast the cover. While
covers containing a synthetic membrane are
likely to prevent precipitation from entering a
closed unit while they are performing as
designed and there are no failures, uncorrect-
ed failure of a cover would allow precipitation
to enter the unit. After leachate removal is
discontinued, this could lead to a "bathtub
effect" where the unit has increasing leachate
volumes and hydraulic head that could lead
to increased leakage rates or overflow.
B. Request For Comments
We invite comments on all aspects of the
model, the values, and data sources used for
specific parameters, and the modeling scenar-
ios for liner performance, including the fol-
lowing:
• Is the cap of 1000 mg/1 concentration for
most constituents in leachate from an
industrial solid waste, management unit,
realistic? If not, provide data on which
waste units generate leachate at higher
concentration levels and what those levels
are likely to be.
• What approaches are reasonable to
address the question of the changing
effectiveness of liners and caps over time?
• Provide data on the occurrence of defects
in liners at the time of installation and on
changes in leakage rate or other data or
indicators of possible changes in liner
defects over time.
• The hazardous waste program deals with
liner/cap uncertainties by requiring treat-
ment prior to disposal. How should such
uncertainties be dealt with for non-haz-
ardous industrial wastes? One possibility
is to rely on quality assurance and control,
long-term monitoring and corrective action
to address non-hazardous waste. Where
uncertainties are too great, we could rely on
the hazardous waste program to list such
wastes as hazardous and require treatment.
A second approach could be to rely on
treatment of certain non-hazardous wastes.
What other approaches are available?
• Should the composite liner scenario, in
Tier 1, use a different leakage rate, or
monte carlo analysis to reflect a range of
7A-6
-------
Protecting Ground Water—Assessing Risk Section
performance levels, rather than a single
value? What values should be used, and
what is the basis for them?
We are also obtaining peer review of the
ground-water model by a group of technical
experts who have been commissioned to pro-
vide an independent analysis of the model
and the way it is used in the guidance. The
results of the peer review will be published in
the Federal Register, so that interested parties
may obtain copies of the review and take it
into account as they prepare their own com-
ments on the ground-water protection com-
ponents of the guide.
Construction and installation quality assur-
ance and quality control are critical to ensur-
ing liner performance. The guidance is
intended to reflect the most up-to-date instal-
lation practices and techniques and the most
appropriate materials and techniques for
installing a final cap on a unit.
• Are there additional practices and tech-
niques that should be reflected in the
guidance?
• For those with experience installing liners
and caps and operating lined units, how
do you measure liner performance and
what are your experiences over time
monitoring liner and cap performance?
II. Identification of
Contaminants
The guidance addresses constituents with
toxicity reference levels (TRLs) (i.e., MCLs
and HBNs). These constituents have been
included because they have human health
concentration levels for exposure through
drinking water. MCLs are drinking water
standards, set in the Safe Drinking Water Act,
which establish the maximum permissible
level of a contaminant allowed in drinking
water. A list of constituents with MCLs used
in this guidance's ground-water risk modeling
can be found in Table 2. A HBN is a level
which is derived from reference doses or ref-
erence concentrations which estimate daily
exposure to a constituent that is likely to be
without appreciable risk of deleterious effects
during a human lifetime. For further informa-
tion on TRLs, see the User's Guide and
Background Document for the Industrial Waste
Management Evaluation Model.
This guidance addresses both MCLs and
HBNs, to the extent available, for each con-
stituent. The constituents specifically
addressed by this guidance include both
organic and inorganic chemicals. Organic
chemicals are chemical compounds contain-
ing carbon.6 Inorganic chemicals include
chemical substances of mineral origin, such
as cadmium and chromium. For the 191 con-
stituents included in the guidance, 51 have
an MCL, 189 have an HBN value, and 41
have both. TRLs may vary from state to state.
States can impose more stringent drinking
water standards than federal MCLs.7 To keep
the software developed for this guidance up
to date and to accommodate concerns at lev-
els different from the current TRLs, the TRL
values can be modified by the user of the
software.
A first step in determining the most appro-
priate waste management unit design is to
identify the constituents in the waste and
expected leachate concentrations from the
waste. For information on determining
leachate concentrations, see the characteriz-
ing waste chapter.
Some regulatory definitions include carbon monoxide, carbon dioxide, etc. as organic compounds, some
definitions exclude them as organic compounds. Lee, C. 1992. Environmental Engineering Dictionary, 2d.
Ed.
7For example, a state can make secondary MCLs, which are not federally enforceable standards, mandato-
ry, or a state may use different exposure assumptions which result in a different HBN.
7A-7
-------
Protecting Ground Water—Assessing Risk Section
Table 2.
List Of Constituents with maximum Contaminant Levels (MCLs)
Organics with an MCL rng/1
Benzene 0.005
Benzo[a]pyrene 0.0002
Bis(2-ethylhexyl)phthalate 0.006
Brornodichloromethane* 0.10
Butyl-4,6-dinitrophenol,2-sec-(Dinoseb) 0.007
Carbon tetrachloride 0.005
Chlordane 0.002
Chlorobenzene 0.1
Chlorodibromomethane* 0.10
Chloroform* 0.10
Dibromo-3-chloropropane 1,2- 0.0002
Dichlorobenzene 1,2- 0.6
Dichlorobenzene 1,4- 0.075
Dichloroethane 1,2- 0.005
Dichloroethylene cis-1,2- 0.07
Dichloroethylene trans-1,2- 0.1
Dichloroethylene l,l-(Vinylidene chloride) 0.007
Dichloropropane 1,2- 0.005
Endrin 0.002
Ethylbenzene 0.7
Ethylene dibromide (1,2-Dibromoethane) 0.00005
HCH (Lindane) gamnia-
Heptachlor epoxide
Hexachlorobenzene
Hexachlorocyclopentadiene
Methoxychlor
Methylene chloride
(Dichloromethane)
Pentachlorophenol
Polychlorinated biphenyls
(Aroclors)
Styrene
TCD Dioxin 2,3,7,8-
Tetrachloroethylene >
Toluene
Toxaphene
(chlorinated camphenes)
Tribromomethane (Bromoform)*
Trichlorobenzene 1,2,4-
Trichloroethane 1,1,1-
Trichloroethane 1,1,2-
Trichloroethylene
(1,1,2-Trichloroethylene)
Vinyl chloride
Xylenes \
mg/1
0.0002
0.0004
0.0002
0.001
0.05
0.04
0.005
0.001
0.0005
0.1
.00000003
0.005
1
0.003
0.10
0.07
0.2
0.005
0.005
0.002
10
Inorganics with an MCL
Antimony
Arsenic
Barium
Berylium
Cadmium
0.006
0.05
2.0
0.004
0.005
Chromium
Mercury
Selenium
Silver**
Thallium
0.1
0.002
0.05
0.10
0.002
.
* Listed as Total Trihalomethanes (TTHMs), constituents do not have individually listed MCLs.
** Silver is a secondary MCL. Secondary MCLs (SMCLs) are non-enforceable guidelines regulating contami-
nants that may cause cosmetic effects, such as skin or tooth discoloration, or aesthetic effects, such as taste,
odor, or color, in drinking water.
7A-8
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Protecting Ground Water—Assessing Risk Section
A. Exposure Assessment:
Understanding Fate
and Transport
A source of ground-water contamination
from a waste management unit is the release
of leachate. Residents who live close to a
waste management unit and who use wells
for water supply can be directly exposed to
waste constituents by drinking or bathing in
contaminated ground water. Residents also
can be exposed by inhaling volatile organic
compounds (VOCs) released during use of
ground water such as during showering,
when volatile compounds can be released to
the air.
Releases from a waste management unit
and subsequent transport of constituents to
ground water are affected by three types of
factors: waste characteristics, site characteris-
tics, and liner system design (as the primary
containment system to minimize release of
constituents of concern out of a unit).
First, the physical, chemical, and biological
properties of the waste/constituents affect the
potential for constituents to leach or other-
wise be released into the environment. For
example, waste characteristics influence how
a liner system prevents or mitigates the
migration of leachate. Wastes that are highly
acidic or alkaline can dissolve soil minerals
and thus increase the hydraulic conductivity
or permeability of a compacted clay liner.
Waste constituent characteristics affect the
movement or transport of constituents
through soil and ground water. For example,
wastes with a density lower than ground
water tend to concentrate in the upper por-
tions of an aquifer, while those with a higher
density concentrate in the lower portions.
The viscosity (tendency to resist internal
flow) of specific contaminants affects their
rate of migration through soil and within an
aquifer. Solubility (which affects the mobile
concentration), chemical structure, and many
other waste constituent properties can affect
contaminant migration.
Second, site characteristics, including geo-
logic setting and hydrology, may inhibit or
facilitate movement of constituents. Natural
subsurface processes, such as biodegradation,
sorption, and precipitation, can attenuate
compounds in the ground water before they
reach receptors. Alternatively, fractures in
rocks can act as conduits and water can move
through them quickly carrying contaminants.
Finally, engineered liners have a variety of
properties that contain constituents to vary-
ing degrees. Compacted clays, geomem-
branes, and composite liners act as hydraulic
barriers to minimize release of leachate.8
Compacted clay liners also can reduce the
concentration of constituent levels through
attenuation. In addition to liners, final covers
placed on waste management units after the
final receipt of waste minimize infiltration of
water into a waste management unit and
thereby further reduce leachate generation
and potential release.9
How do contaminants move
from waste management units
to ground water?
Figure 1 illustrates the concept of aqueous
phase waste constituent movement from a
waste management unit to a monitoring well.
As can be seen in the figure, contaminant
concentrations are typically highest near the
source.
Waste constituents from a waste manage-
ment unit migrate through the unsaturated
and saturated zones where physical, chemi-
cal, and biological processes act upon them.
The type of geological material below the unit
also affects the rate of movement because of
differences in hydraulic conductivity. More
"For further information on liners, see the section on designing and installing liners.
Tor further information on covers and impact on infiltration, see the chapter on performing closure and
post-closure care.
7A-9
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Protecting Ground Water—-Assessing Risk Section
Figure 1. Representation of Fate and Transport Analysis
Monitoring Well
roiniorMonnQnnii 7^ / y
/BWUMMW ConCMlbWUQft vJmiSa / /
OMSiaglL // /
I I I I I I I I
rapid movement of waste constituents can be
expected through coarse-textured materials
such as sand and gravel than through fine-
textured materials such as silt and clay (see
textbox on examples of soil permeability).
The physical and chemical composition of
the geologic material is equally important.
Fine-textured material with a high clay con-
tent tends to impede contaminant migration
both by having a low hydraulic conductivity
and through the effects of ion exchange and
physical adsorption.10
Contaminant movement through unsaturated zone
As waste constituents migrate, geological
materials and biological processes interact
with waste constituents. These interactions,
which are called attenuation, lead to immobi-
lization of potential ground-water contami-
nants. Attenuation processes are dependent
upon pH, temperature, vapor pressure, and
other compounds in the subsurface environ-
ment. Attenuation processes include sorption
of cations and anions on soil mineral sur-
faces, such as clays, and direct precipitation
of molecules from solution.11 Sorption is the
process by which leachate molecules adhere
to the surface of individual clay, soil, or sedi-
ment particles. Sorption causes a decrease in
the total dissolved solids in the leachate.
Clays are good sorbants for two reasons: sur-
face charge and high surface area.
Examples of Permeability of
Common Natural Soil Formations
Formation
Coefficient of Permeability
Mississippi river deposits
Dune sand
Loess
Clay
(cm/sec)
0.02 to 0.12
0.1 to 0.3
0.001
< 0.0000001
Sharma, H., and S. Le;wis. 1994. Waste
Containment Systems, Waste Stabilization, and
Landfills. • -,'""'""'
7A-10
"Boulding, R. 1995. Soil, Vadose Zone, and Ground-Water Contamination: Assessment, Prevention, and
Remediation.
"These attenuation processes can occur in both the vadose and saturated zones.
-------
Protecting Ground Water—Assessing Risk Section
Samples of Attenuation Processes
Attenuation processes are dependent upon pH, temperature, pressure, and other
compounds in the subsurface environment.
Biological degradation: decomposition of a substance into more elementary com-
pounds by action of microorganisms such as bacteria. Sullivan. 1993. Environmental
Regulatory Glossary, 6th Ed. Government Institutes.
Bio-uptake: the uptake and, at least temporary, storage pf a chemically an exposed
animal. The chemical can be retained in its original form and/or modified by enzy-
matic and non-enzymatic reactions in the body. Typically, the concentrations of-the
substance in trie organism exceed the concentrations in the environment since the
organism will store the substance and not excrete it. Sullivan. 1993. Environmental
Regulatory Glossary, 6th Ed. Government Institutes'.- ' - ^,
Filtration: physical process whereby solid particles and large dissolved molecules
suspended in a fluid are entrapped or removed by the pore spaces of the soil and
aquifer media. Boulding, R. 1995. Soil, Vadose Zone, and. Ground-Water Contamination:
Assessment, Prevention, and Remediation. „ ', „
Hydrolysis: a chemical process of decomposition in which the elements of water
react with'another substance to yield one or more entirely new substances. This trans-
formation process changes the chemical structure of the.substance. Sullivan. 1993.
Environmental Regulatory Glossary, 6th Ed. Government-Institutes.
Oxidation/Reduction (Redox) reactions: involve a transfer of electrons and, there-
fore, a change'in the oxidation state of elements. The chemicaLproperties for elements
can change substantially with changes in the oxidation state. U.S. EPA. 1991. Site
Characterization for Subsurface Remediation. ;
Precipitation: chemical or physical change whereby a. contaminant moves from a
dissolved form in a solution to a solid or insoluble form. It reduces the mobility of
constituents, such as metals. Unlike sorption, precipitation is not generally reversible.
Boulding, R. 1995. Soil, Vadose Zone, and Ground-Water Contamination: Assessment,
Prevention, and Remediation.
Sorption: the ability of a chemical to partition between the liquid and solid phase
by determining its affinity for adhering to other solids in the system such as soils or
sediments; The amount of chemical that "sorbs" to solids-ahd does not move through
the environment is dependent upon the characteristics oCIhe chemical, the character-
istics of the surrounding soils and sediments, and the quantity of the chemical.
Sorption generally irreversible. Sorption often includes both adsorption and ion
exchange. '. _' . :.;.:;: -."••- •--:""\ - -.-.
7A-11
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Protecting Ground Water—-Assessing Risk Section
In addition, microorganisms frequently are
the catalysts or promoters of reactions in the
subsurface. Microorganisms can break down
wastes, produce various organic acids, and
use up available oxygen supplies creating
anaerobic environments. Whether soil con-
ditions are oxidizing (aerobic) or reducing
(anaerobic) will strongly affect the types of
microbial activity and contaminant degrada-
tion processes that may occur. For more
information on specific attenuation processes,
see the text box on the previous page.
Contaminant movement through the
saturated zone
Eventually, the waste constituents can
reach the saturated zone where dilution or
dispersion can occur. Dilution reduces the
concentration of constituents but does not
Examples of Attenuation Mechanisms
for Specific Contaminants
Attenuation mechanisms
Contaminants
Arsenic
Barium.
Beryllium
Cadmium
Chromium
Mercury
Nickel
Selenium
Zinc
Volatile organic
compounds (VOCs)
Bagchi, A. 1994. Design, Construction, and
Monitoring of Landfills.
Adsorption, precipitation
Adsorption, precipitation
Precipitation
Adsorption, precipitation
Adsorption, precipitation
Adsorption, precipitation,
redox reactions
Precipitation, sorption
Adsorption, anion
exchange
Adsorption, precipitation
Biological uptake
alter their chemical structure. Dilution is
directly related to ground-water velocity and
the size of the leachate plume tends to
increase with more rapid ground-water flow.
Attenuation also occurs in the saturated
zone. Attenuation processes can remove or
degrade waste constituents through filtration,
sorption, precipitation, and hydrolysis. For
example, filtration is the entrapment of solid
particles and large dissolved molecules in the
pore spaces of the soil and aquifer.
If contamination reaches a monitoring
well, corrective action may need to be initiat-
ed to protect human health and the environ-
ment. The overall goal of any corrective
action should be to perform a technically and
economically feasible risk-reduction,
designed to achieve a cleanup standard at a
specified point on the facility property.
Using the ground-water pathway as an exam-
ple, corrective action for new units should
have as a goal a reduction of constituent con-
centration levels to the ground-water protec-
tion standards, that is the TRL (e.g., a MCL
or HBN) at the monitoring point. For more
information on corrective action, see the
chapter on taking corrective action.
B. Risk Characterization:
The 3-Tiered Approach
The three assessment tiers and the IWEM,
the ground-water model included in this
guidance for Tiers 1 and 2, can be used to
help select protective practices to manage
waste constituents. First determine state
requirements for liners and waste limits for
land application and comply with those
requirements. IWEM and the three-tiered
assessment recommended here can help
choose management controls where there is
flexibility for site-specific determinations in
state regulations.
7A-12
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Protecting Ground Water—Assessing Risk Section
It is important to understand how Tier 1
and 2 incorporate risk assessment. The goal
in choosing a liner design or waste applica-
tion rate is to prevent, to the extent possible,
or to minimize ground-water contamination.
Defining a monitoring well (rather than a
drinking water well) as the point to measure
benchmark concentrations is a way to asses
performance of the liner system and potential
migration of contaminants from the unit. The
human health benchmark values serve as a
flag for additional action to characterize a
release, correct problems with the liner, and
cleanup contamination.
At Tier 1, the model analyzes a monitoring
well set at 150 meters from the unit boundary
to accommodate states that have adopted a
non-degradation policy to protect ground
water for current and future users. At Tier 2,
IWEM allows a user to set an alternative dis-
tance to the monitoring well. This approach
recognizes that, on a site-specific basis, an
alternative distance to monitoring wells may
be appropriate, as long as the distance is
agreed to in consultation with all the interested
parties. EPA's Composite Model for Leachate
Migration with Transformation Products is the
basis for the Tier 1 and 2 analyses.
EPA's Composite Model for Leachate Migration
with Transformation Products
The Tier 1 and Tier 2 modeling tools are
based on EPA's Composite Model for
Leachate Migration with Transformation
Products (EPACMTP).12 EPACMTP simulates
subsurface fate and transport of contami-
nants leaching from the bottom of a waste
management unit and predicts concentra-
tions of those contaminants in a downgradi-
ent well. In making these predictions, the
model accounts for many complex processes13
that occur as waste constituents and their
transformation products move to and
through ground water. As leachate carrying
waste constituents migrates through the
unsaturated zone to the water table, attenua-
tion processes such as adsorption and degra-
dation reduce constituent concentrations.
Ground-water transport in the saturated
zone further reduces leachate concentrations
through dilution and attenuation. The con-
centration of constituents arriving at a recep-
tor well, therefore, is generally lower than
that in the leachate released from a waste
management unit.
EPACMTP can determine the effect of fate
and transport through the unsaturated and
saturated zone on leachate constituent con-
centrations. In the unsaturated zone, it simu-
lates one-dimensional vertical migration with
steady infiltration of constituents from the
waste management unit. In the saturated
zone, it simulates three-dimensional ground-
water flow (horizontal as well as vertical
spreading of a contaminant plume to incorpo-
rate infiltration from waste management
units).14 EPACMTP is a refined version of ear-
lier EPA fate and transport models. With these
improvements, the model considers not only
the subsurface fate and transport of con-
stituents but also the formation and the fate
and transport of transformation (daughter and
granddaughter) products. The model also can
simulate fate and transport of metals, taking
into account geochemical influences on the
mobility of metals. EPACMTP has been favor-
ably reviewed by EPA's Science Advisory
Board (SAB) which stated that it "represents
the state of the art for such analyses."15
12For more detailed information on EPACMTP, consult the EPA's Industrial Waste Management Evaluation
Model (EPAIWEM) background materials.
13The processes addressed by the model include transport through the unsaturated zone, advection due to
ambient ground-water flow, hydrodynamic dispersion, first-order decay, linear and non-linear equilibrium
sorption of chemicals, decay reactions and transport of daughter and granddaughter products, effects of
water table mounding, and the duration of leachate release.
"This effect is called ground-water mounding underneath a waste unit.
"60 FR 66344, 66367 (December 21, 1995).
7A-13
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Protecting Ground Water—Assessing Risk Section
Another unique feature of EPACMTP is
that it can calculate the reduction in leachate
concentration expressed by a dilution/attenu-
ation factor (DAF). A DAF is defined as the
ratio of the expected leachate concentration to
the monitoring well concentration. The DAF
is then determined from the relationship:
DAF = -
CMW
where: G. is the leachate concentration (mg/L)
CMW is the monitoring well
concentration (mg/L).
The magnitude of a DAF reflects the capa-
bilities of the unsaturated and saturated zone
to retard or slow the transport of constituents
to a monitoring well. The lowest possible
value of DAF is one; a value of DAF=1 means
that there is no dilution or attenuation at all;
the concentration at a monitoring point is the
same as that in the waste. High values of
DAF on the other hand correspond to a high
degree of dilution and attenuation. For any
specific site, the DAF depends on the interac-
tion of waste constituent characteristics (e.g.,
whether or not the constituent degrades or
sorbs), site-specific factors (e.g., geology),
and physical and chemical processes in the
subsurface environment.
EPACMTP was developed for regulatory
purposes. The analyses done with it are
based upon simplifying assumptions, and
data may not apply or may be inappropriate
for evaluating a specific waste management
unit. EPACMTP does not account for hetero-
geneities in the flow system, such as frac-
tures. It does not handle colloidal and immis-
cible (NAPL) transport. EPACMTP does not
account for multi-phase (vapor) flow; nor
does it account for reactive transport other
than sorption and decay. Thus the results of
the Tier 1 and Tier 2 modeling with EPAI-
WEM do not reflect these characteristics of a
particular waste management unit or loca-
tion. Waste management unit systems which
exhibit unique heterogeneities or have several
phases, such as colloids, and NAPLs should
be evaluated with a tool that is more appro-
priate to the particular characteristics of the
facility. The assumptions used and potential
limitations of EPACMTP are discussed in the
Industrial Waste Management Evaluation Model
Background Document, EPACMTP Background
Document. U.S. EPA. 1996; and EPACMTP
Background Document for the Finite Source
Methodology. U.S. EPA. 1996.
Leachate Concentration Threshold Values
(LCTVs) ;
The Tier 1 and Tier 2 assessment tools rec-
ommend liner system designs or the appro-
priateness of land application based on calcu-
lated protective leachate thresholds for all
wastes in a unit. These LCTVs are the maxi-
mum leachate concentrations for which water
in a monitoring well is not likely to exceed
the given TKL. The LCTV accounts for waste
releases through a liner and dilution and
attenuation in the unsaturated and saturated
zone prior to reaching a monitoring well.
The LCTV for a specific constituent is the
product of the TRL and the dilution and
attenuation factor (DAF):
LCTV = DAF * MCL
or LCTV = DAF * HBN
The adequacy of a liner system design is
evaluated by comparing the estimated waste
constituent leachate concentrations to the
LCTV The Tier 1 National Evaluation Model
is the most conservative and calculates
LCTVs using data collected on waste man-
agement units throughout the United States.16
LCTVs are generated for all unit types (i.e.,
landfills, waste piles, surface impoundments,
"For additional information on the nationwide data used in the modeling, see the IWEM Background
Document
7A-14
-------
Protecting Ground Water—Assessing Risk Section
and land application units). LCTVs are also
generated according to the type of liner
design (i.e., no-liner, single liner, or compos-
ite liner).17 At Tier 2, a user can input site-
specific data for 6 to 7 parameters depending
on the type of waste management unit.
1. Tier I: National Evaluation
The Tier 1 National Evaluation lookup
tables (see Appendix I) identify whether a pro-
posed liner design or land application is appro-
priate based on the constituent concentrations
present in the leachate from a waste manage-
ment unit. It allows you to compare the expect-
ed waste constituent concentrations to the cal-
culated LCTVs in the lookup tables to help
make this determination. The LCTVs are the
maximum leachate concentration which does
not result in a ground-water concentration at a
downgradient well which exceeds a given TRL.
The lookup tables do not require site-specific
data, only waste constituent concentrations,
and are simple and easy to use. Alternatively,
the EPAIWEM software contains a database
with the Tier 1 lookup tables.
The lookup tables were developed from
EPACMTP modeling results. Using input
parameters from national waste and manage-
ment unit characteristics,18 EPACMTP simu-
lated four waste management unit types —
landfills, surface impoundments, waste piles,
and land application units — and deter-
mined DAFs for 175 organic chemicals and
16 metals species. In developing the DAF
values, EPACMTP performed simulations on
a nationwide basis that reflect expected varia-
tions in site and hydrogeological conditions.
To account for this variability, the EPACMTP
fate and transport model is linked to a monte
carlo module which generates model input
parameter values from the probability distrib-
ution of each parameter. The monte carlo
method involves the repeated generation of
values for the uncertain input variables
(drawn from the known distribution) and the
application of the fate and transport model to
generate a series of model responses (down-
gradient well concentrations). The generation
of random parameter values and fate and
transport simulation is repeated many times
to determine the probability distribution of
the downgradient well concentrations. The
DAF value is developed from this probability
distribution.
The LCTVs in the lookup table were deter-
mined by multiplying the EPACMTP 90th per-
centile DAF values with constituent-specific
TRLs. DAF values are determined by selecting
the monitoring well concentration for which
90 percent of the peak concentrations (or peak
30-year average concentration for carcinogens)
analyzed in a particular scenario are less than
the toxicity benchmark at the monitoring well.
In addition, several EPACMTP parameters
were fixed at conservative values. Specifically,
the monitoring well is assumed to be located
on the contaminant plume centerline. This
ensures that the highest constituent concentra-
tions in the plume would reach the monitoring
well. Similarly, the national evaluation model-
ing limited the potential distance to the moni-
toring well to 150 meters in order to monitor
Information Needed to Use
Tier 1 Lookup Tables
Waste management
unit types:
Waste constituent
names:
Leachate
concentrations:
Landfill, surface
impoundment, waste
pile, or land applica-
tion unit.
Constituents expected
in leachate.
Expected leachate
concentration of each
constituent or concen-
tration iii surface
impoundments or
waste to be applied.
17LCTVs are influenced by liner designs because of different infiltration rates.
18See the EPAIWEM Background Document for detailed information on parameter input values.
7A-15
-------
Protecting Ground Water—Assessing Risk Section
the performance of the liner system and to
avoid ground-water degradation, not because
of the presence of human receptors at that dis-
tance. For these reasons, the National
Evaluation LCTVs are relatively conservative.
How do I use the Tier 1 lookup
tables?
As die first step in any ground-water risk
assessment, characterize the waste going into a
unit and determine the expected waste con-
stituent leachate concentrations. Estimate
leachate concentrations using knowledge of
waste generation processes and/or an analytical
leaching test appropriate to the circumstances,
such as the Toxicity Characteristic Leaching
Procedure (TCLP). For more information on
estimating a waste constituent concentrations
and appropriate leaching tests, refer to the
chapter on characterizing waste.
A comparison of the expected leachate con-
centrations to the LCTVs in the Tier 1 lookup
tables can help evaluate the type of liner need-
ed for the proposed waste management unit or
whether waste should be land applied. The
only input needed for this tool is the expected
waste constituent leachate concentration. Tier
1 lookup tables are available for each waste
management unit type. See Appendix I.
Alternatively, EPAIWEM has a database with
the lookup tables that can be used.
Tier 1 Notional Evaluation Example
The following example illustrates the Tier
1 process for evaluating a proposed liner
design for an industrial landfill. The example
assumes the expected leachate concentration
for toluene is 1.6 mg/L and styrene is 0.5
mg/L. In the Tier 1 process, the user would
compare the estimated constituent leachate
concentrations to the LCTVs in the National
Evaluation lookup tables summarized in
Table 3.
Table 4 shows the results of comparing
estimated constituent concentrations to the
LCTVs in the lookup tables. To determine
whether a proposed liner design is appropri-
ate, the example relied on LCTVs based on
MCLs. The lookup tables also allow compar-
isons to LCTVs based on HBNs.
Because EPA does not expect leachate con-
centrations from waste management units
covered by this guidance to exceed 1,000
mg/L for a single constituent, the waste con-
stituent input values and all Tier 1 and Tier 2
LCTVs have been capped at a maximum
value of 1,000 mg/L. For any waste con-
stituent covered by the Toxicity Characteristic
Waste
Table 3
Example National Evaluation Lookup Table for Landfills
MCL HBN
(mg/L) (mg/L)
No Liner/In-Situ Soil*
LCTVs (mg/L)
Single Liner
Composite Liner
based on
MCL
based on based on based on based on based on
HBN MCL HBN i MCL HBN
* Section B of this chapter describes designing and installing liners of different types.
Toluene
Styrene
1.0
0.1
7.0
7.0
2.2
0.22
15
15
4.6
0.46
32
32
1000
1000
1000
1000
7A-16
-------
Protecting Ground Water—Assessing Risk Section
Table 4
Example National Evaluation Lookup Table Comparison Results
Waste
Constituent
Toluene
Expected
Concentration in
Leachate (mg/L)
1.6
Finding and Recommendation
Does not exceed no-liner/in-situ soil LCTY No-
liner/in-situ soil recommended
Styrene
0.5
Exceeds no-liner/in-situ-soil and single liner
LCTVs. Composite liner recommended
(TC) Rule (40 CFR Part 261), the LCTV is
capped at the TC Rule regulatory level.
Leachate concentrations above this level are
considered to be characteristic hazardous
waste. If any waste constituent concentra-
tions exceed the toxicity characteristic maxi-
mum concentrations, the waste is considered
RCRA hazardous and outside the scope of
this guidance.
What do the results mean and
how should I interpret them?
If the expected leachate concentrations for
all constituents are lower than the no-liner
LCTVs, the proposed landfill does not need a
liner to contain this waste. If any constituent
concentration is higher than the no-liner
LCTV, then a single compacted clay liner or
composite liner would be recommended for
containment of the waste. If any concentra-
tion is higher than the single-liner LCTV, then
the recommendation is at least a composite
liner. If any concentration is higher than the
composite liner, consider pollution preven-
tion, treatment, or additional controls. For
waste streams with multiple constituents,
select the most protective liner that is speci-
fied for any one constituent.
Continuing with the example above, the
recommendation is a composite liner because
the styrene concentrations exceed the single
liner threshold even though toluene did not.
Interpretation for land application is similar. If
all the waste leachate concentrations are below
the threshold values in the Tier 1 lookup
tables, land-applying waste may be appropriate
for the site. It is still important, however, to
evaluate other land application factors outlined
in Section C of this chapter. These will still
influence whether land application is appropri-
ate and at what rate. If the waste had several
constituents whose concentrations were less
than the land application threshold and one
constituent exceeding the land application
threshold, the recommendation is that land
application is not appropriate.
After conducting the Tier 1 National
Evaluation, consider the following steps.
• Consider waste reduction/pollution pre-
vention, recycling, or treatment. If the
waste has one or very few "problem"
constituents that call for a more stringent
and costly liner system (or which make
land application inappropriate), evaluate
pollution prevention, recycling, and
treatment efforts for those constituents.
Waste reduction, recycling, or treatment
options that before may have appeared
economically infeasible, may be
worthwhile if they can reduce the prob-
lem constituent concentration to levels
which result in a different liner recom-
mendation or make land application
7 A-17
-------
Protecting Ground Water—Assessing Risk Section
appropriate. After implementing these
measures, repeat the Tier 1 evaluation.
Based on the above example, pollution
prevention, recycling, or treatment mea-
sures could be used to reduce the styrene
concentrations below 0.46 mg/L so that a
single liner is recommended for the unit.
Consult the chapter on integrating pollu-
tion prevention, recycling, and treatment
for ideas and tools.
• Implement recommendations. This
option is the most straightforward.
Design the unit based on the liner
recommendations of the Tier 1 lookup
tables. In the case of land application,
develop a land application system (after
evaluating other factors) if the design
lookup tables found land application to
be appropriate for all constituents. In
either case, consult the state to ensure
compliance with state regulations, which
could require more protective measures
than the Tier 1 lookup tables recom-
mend.
• Conduct additional evaluations.
Conduct either a Tier 2 Location
Adjusted Evaluation or a Tier 3 site-
specific ground-water fate and transport
analysis as discussed below.
Figure 2 illustrates the basic steps for
using the Tier 1 lookup tables to deter-
mine whether a liner design or land
application is appropriate.
2. Tier 2: Location-Adjusted
Evaluation
The Tier 2 Location-Adjusted Evaluation is a
method in which a limited number of site-spe-
cific parameters are used to determine the
effect on the DAFs and the resulting LCTVs.
To facilitate this evaluation, EPA has developed
a set of artificial neural networks (one for each
waste management unit type) that utilizes
information concerning the waste management
unit and the hydrogeological conditions of the
site to determine the appropriate liner type for
containment of the wastes. When calculating
LCTVs, a user can take into account a limited-
number of site-specific considerations without
having to run the EPACMTP or another
ground-water fate and transport model. As
with any ground-water assessment, discuss the
results of the Tier 2 evaluation with the state
and public before selecting a liner design or
land-applying waste.
What are the basic principles
and components of the model?
The Tier 2 artificial neural network pro-
gram that has been incorporated into a
stand-alone executable computer program
requires no specialized training in EPACMTP,
neural networks, or statistics. The Tier 2 tool
What are neural networks?
Neural networks are an information process-
ing method. The revolutionary aspect of
neural networks is their ability to learn com-
plex patterns and/or be trained to adjust to
new data. Neuralnetworks apply knowledge
from past experience to new problems.
Neural networks acquire, this knowledge by
training on a specified set of combinations of
input data. After the network has been
trained and validated, the model may use
data it has not seen previously for prediction,
classification, time series analysis or data seg-
mentation. Unlike traditional statistical meth-
ods, neural networks do not require assump-
tions about the form or distribution of the
data to analyze it.
Additional information on neural networks is
available in the Industrial Waste Management
Facility Design Evaluation Model Background
Document and on the Internet at
htm1>.
7A-18
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Protecting Ground Water—-Assessing Risk Section
uses a multi-layer perception
(MLP) computing model and
software package as the
neural network for this
model. Using hundreds of
thousands of actual
EPACMTP realizations, the
neural network was
trained to estimate the
DAFs that EPACMTP gen-
erated based on changes in
specific combinations of
input parameters." The
neural network closely
matches the results that
EPACMTP generated.
Using the neural-net-
work-estimated DAFs, the
software calculates corre-
sponding LCTVs by multi-
plying the DAFs for each
constituent by its appropri-
ate TRL. The model will
then compare the expected
leachate concentrations to
these LCTVs and identify a
recommended liner for
landfills, surface impound-
ments, and waste piles. The
model can evaluate in-situ
soil, compacted clay liners,
and other liner designs for
which the resulting infil-
tration rate is known.
Figure 2. Process Diagram: Use of National Evaluation
Lookup Tables
Identify proposed WMU type.
I
Estimate waste leachate concentration for
all potential constituents expected to be
present in the waste.
±
Compare expected leachate concentrations
to calculated LCTVs for all potential
constituents.
Implement liner
and/or land
application
recommendations
Implement
pollution
prevention
recycling, or
treatment.
YES
Proceed to Tier 2 location-adjusted
evaluation or Tier 3 site-specific ground-
water fate and transport analyisis.
In developing and training the neural net-
works, problems were encountered when the
extremes of the distributions were used as
input to the training. Training of the neural
networks was then limited to parameter val-
ues between the 10th and 90th percentile.
The composite liner infiltration rate assumed
in Tier 1 (3 x 10'5 for landfills) was outside
the 10th to 90th percentile range (0.024 to
0.45 m/yr for landfills), and thus the neural
networks were not trained using this value.
Because the use of infiltration rates outside
the range over which the neural networks
were trained will result in significant error, the
Tier 2 Location-Adjusted Evaluation does not
explicitly address the composite liner scenario.
The proposed guidance still allows for
assessment of the composite liner scenario
through the Tier 1 and Tier 3 evaluations. EPA
is seeking comment on how to address inclu-
sion of the composite liner scenario in the
Tier 2 Location-Adjusted Evaluation. Options
"The Background Document and User's Guide discuss training the neutral network.
7A-19
-------
Protecting Ground Water—Assessing Risk Section
currently under consideration include: devel-
opment of multiple networks—one for low
infiltration rates and one for high infiltration
rates; and use of a Windows version of
EPACMTP (currently under development).
What input parameters most
strongly influence Tier 2 results?
EPA conducted numerous analyses to
identify the input parameters that had the
greatest influence on the LCTVs generated by
the model. These "sensitive parameters" are
those that have the most significant effect on
model results given a relatively small change
in input values.
Waste management unit area. Area cov-
ered by the waste management unit in
square meters.
Infiltration, rate. Rate at which leachate flows
from the bottom of a waste management
unit (including any liner) into the unsatu-
rated zone beneath the waste management
unit. An area's rainfall intensity affects
infiltration rates as does the performance
of the liner system. Users can either input
infiltration rates directly or allow the Tier 2
program to estimate values for the no—
and single—liner scenarios based on the
unit's geographic location (or impoundment
characteristics for'surface impoundments).20
Depth, to the water table. The depth in
meters of the zone between the land sur-
face and the water table.
Aquifer thickness. The thickness of an
aquifer measured in meters.
Radial distance to monitoring well.
Distance in meters from the waste man-
agement unit to a monitoring well.
• Organic carbon distribution coefficient
(KOQ. A function of the nature of a sor-
bent (the soil and its organic carbon content)
and the properties of a chemical (the leach-
ate constituent). It is equal to the ratio of the
solid and dissolved phase concentrations.
The higher the value of the distribution
coefficient, the higher the adsorbed-phase
concentration, meaning the constituent
would be less mobile. For metals, include
Kd, but if Kd is not known, software can
estimate if given the ground-water pH.
• Decay rate. The rate at which constituents
degrade or decay within an aquifer due to
chemical hydrolysis or biodegradation.
Measured in liters per year. The default
decay rate represents degradation from
chemical hydrolysis only, since biodegra-
dation rates are often strongly influenced
by site-specific factors.
Because site-specific data for all of the sensi-
tive parameters may not be available to a user
of the software, the model contains "default"
values for these parameters. The default values
were derived from a number of sources, includ-
ing a survey of industrial waste management
units, a hydrogeologic database, water-balance
modeling, and values reported in the scientific
literature. The selection of default values is
explained in the IWEM Technical Background
Document. Use all site-specific data available,
as the estimated leachate concentration values
generated using primarily default data will
tend to be conservative and may not accu-
rately represent the conditions at the site.21
i
How do I use the model?
The CD-ROM contairis the Tier 2 model.
The User's Guide for the Industrial Waste
Management Evaluation Model provides com-
plete installation instructions. The software
will prompt a user to enter information on
7A-20
"The software can estimate infiltration rates for surface impoundments if impoundment characteristics
such as ponding depth, thickness of sediment layer, and conductivity of sediment layer are input.
"A Tier 2 evaluation is not always less conservative than a Tier 1. For example, if a site has a very large
area, a very shallow water table, and/or the aquifer thickness is well below the national average, then the
Tier 2 evaluation results can be more stringent than the Tier 1 analysis results. -
-------
Protecting Ground Water—Assessing Risk Section
Parameters
Infiltration rate*
Waste management unit area
Depth to the water table
Aquifier thickness
Distance from receptor well
waste management unit type,
waste constituents, and
expected leachate concentra-
tions. In addition, it will
prompt a user to enter site-
specific values for known
selected parameters—those
that were identified as being
the most sensitive—replac-
ing the default values devel-
oped from the EPACMTP
input data. Figure 3 is an
example of some of the Tier
2 software screens. When
conducting a Tier 2 evalua-
tion, use documented and
realistic data for the site.
When changing default values, provide justi-
fications of the data sources and values as
necessary. Default values can be used if repre-
sentative of site-specific conditions. State
agencies and the public can review a loca-
tion-adjusted evaluation and may question
any unsupported assumptions.
Tier 2 Location-Adjusted Evaluation Example
Continuing the example from Tier 1 for
toluene and styrene disposal in a proposed
landfill, consider the location-adjusted data
for the following sensitive parameters.
The Tier 2 evaluation will develop LCTVs
based on the location-adjusted data and com-
pare expected leachate concentrations to the
calculated LCTVs to determine a recommend-
ed liner system. The results recommend a
single liner system to dispose of toluene and
styrene under the location-adjusted condi-
tions. The Tier 2 evaluation also provides a
detailed presentation of results which
includes a summary of inputs and accompa-
nying narrative, leachate concentrations, DAF
values, toxicity benchmarks (MCLs/HBNs),
chemical-specific parameters (KOC and decay
rate), and LCTVs. This allows a user to
understand how the LCTV values were calcu-
Table 5.
Example Site-Specific Parameters
Site-Specific Data
Local climate: Madison, WI
Soil Type: fine-grained soil
15,000 m2
10m
25m
150m
*The Tier 2 model can calculate an infiltration rate for the liner
scenarios based on local climate and soil data.
lated and how the liner design recommenda-
tions were developed. Because the detailed
results give the chemical-specific DAF value
for each liner scenario evaluated, a user can
calculate different LCTV values using differ-
ent TRLs, such as 0.1 times the MCL value or
10 times the HBN value.
What do the results mean and
how should I interpret them?
As in the Tier 1 analysis, if the expected
leachate concentration is lower than the no-
liner LCTV, then the waste management unit
does not require a liner other than the native
soil. If the expected leachate concentration is
higher than the no-liner LCTV, then the rec-
ommendation is at least a single compacted
clay liner. If the expected leachate concentra-
tion is higher than the single-liner LCTV, then
the recommendation is to consider pollution
prevention, treatment, or additional controls.
For waste streams with multiple constituents,
the recommendation is the most conservative
liner design identified for any one constituent.
As in the Tier 1 evaluation, consider inte-
grating pollution prevention, recycling, and
treatment practices. If you choose to follow
7A-21
-------
Protecting Ground Water—Assessing Bisk Section
Figure 3. Example Input Screens for Tier 2 Model
S UKteUMl Wosio M4nag»oif« FoaMy DeaK)» evolooaoo MOOM - IVnaaaxm) -yjxaaaBfavxseii
7A-22
-------
Protecting Ground Water—Assessing Bisk Section
Figure 3. Example Input Screens for Tier 2 Model (cont.)
j»| tedestooi Waste Management Fac3fty Design Gyotaalion MorfoJ - Rfo&talweiel - [tocatioa Admsted „
tnrfu*b«jt Wotitt MfutAQom&nt Fooltty Destqa tvoIwolJOO MoeJot - ^fmtti«dL>¥«mj - Itoca&oo AiWastedZ
7A-23
-------
Protecting Ground Water—-Assessing Risk Section
the Tier 2 recommendations, consult with
the state to develop a more detailed design
plan for the waste management unit.
Alternatively you can undertake a compre-
hensive assessment to more accurately
reflect site-specific conditions. See Tier 3:
Site-Specific Ground-Water Fate and
Transport Analysis, for further information.
In addition to the Tier 2: Location-
Adjusted Evaluation model, other fate and
transport-models have been developed that
incorporate location-specific considerations,
such as the American Petroleum Institute's
(API's) Graphical Approach for Determining
Site-Specific Dilution-Attenuation Factors.22 API
developed its approach to calculate facility-
specific DAFs quickly using graphs rather than
computer models. Graphs visually indicate the
sensitivity to various parameters. This approach
can be used for impacted soils located above
or within an aquifer. This approach accounts
for attenuation with distance and time due to
advective/dispersive processes. API's approach
has a preliminary level of analysis that uses a
small data set containing only measures of the
constituent plume's geometry. The user can
read other necessary factors off graphs pro-
vided as part of the approach. This approach
also has a second level of analysis in which
the user can expand the data set to include
site-specific measures, such as duration of
constituent leaching, biodegradation of con-
stituents, or site-specific dispersivity values.
At either level of analysis, the calculation
results in a DAE This approach is not appro-
priate for all situations; it should not be used
to estimate chemical concentrations in active
ground-water supply wells or to model very
complex hydrogeologic settings, such as frac-
tured rock. Consult with the state to discuss
the applicability of the API approach or any
other location-adjusted model prior to use.
Why is it important to use a qualified
professional?
• Fate and transport modeling can be
extremely complex.
• Incorrect fate and transport modeling can
result in a liner system' that is not suffi-
ciently protective or an inappropriate
land application rate.
• To avoid incorrect analyses, check to see
if the professional has sufficient training
and experience at analyzing ground-water
flow and contaminant fate and transport.
3. Tier 3: Site-Specific Ground-
Water Fate and Transport
Analysis
Site-specific ground-water fate and trans-
port analysis is the most detailed method for
estimating potential risk to ground water and
evaluating alternative liner designs or applica-
tion rates. If the Tier 1 and Tier 2 modeling
do not adequately simulate conditions at a
proposed site because the hydrogeology of the
site is complex, consider a site-specific risk
assessment.23 Consult with the state and use a
qualified professional experienced in ground-
water modeling if appropriate. Talk to state
officials and/or appropriate trade associations
to solicit recommendations for a good consul-
tant to perform the analysis.
How to select a site-specific
ground-water fate and transport
model?
Estimating exposure concentrations in
ground water using models can be a complex
task due to the many physical and chemical
7A-24
"A copy of API's user manual can be found on the CD-ROM. The Technical Background Document and User
Manual (API Publication 4659) can be obtained from the American Petroleum Institute, 1220 L Street,
NW, Washington, DC 20005, 202 682-8375.
:3For example, if the depth to ground water at the site is over 250 feet, use of the Tier 2 Location-adjusted
Evaluation tool may not be appropriate because the model is based on data from units with shallower
depths to ground water.
-------
Protecting Ground Water—Assessing Risk Section
processes that affect transport and transfor-
mation of constituents in ground water.
Hundreds of different models have been
developed to simulate the fate and transport
of constituents in ground water. Proper
selection and application of ground-water
models requires a thorough understanding of
the waste and the physical, chemical, and
hydrogeologic characteristics of the site.
In addition to evaluating whether a model
will adequately address site characteristics,
ask the following questions to ensure that the
model will provide accurate, meaningful
results.
• What is the source of the model and how
easy is it to obtain? Is it a proprietary
model?
• Are documentation and user's manuals
available for the model and, if so, are they
well-written and easy to use?
• Has the model been verified against ana-
lytical solutions and other models and, if
so, are the test cases available so that your
consultant can test the model on his/her
computer system?
• Has the model been validated using field
data?
As with all modeling, consult with the state
before investing significant resources in a site-
specific analysis. The state may have a list of
preferred models and may be able to help
plan the fate and transport analysis.
EPA's report Selection Criteria for
Mathematical Models Used in Exposure
Assessments: Ground-Water Models lists a num-
ber of criteria to evaluate before selecting a
ground-water fate and transport model. It also
provides a primer on ground-water flow. This
document is available through the National
Technical Information Service, Springfield,
Virginia, 22161, phone: 800 553-6847,
Internet: . The
American Society for Testing and Materials
(ASTM) also provides guidance for conduct-
ing modeling and a listing of guidance materi-
al can be found in the sidebar.
Examples of questions to answer before
selecting a model are provided below.
• Does a confined aquifer, an unconfined
aquifer, or both need to be simulated?
• Does the ground water flow through porous
media, fractures, or a combination of both?
• Is it necessary to simulate three-dimen-
sional flow or can the dimensionality be
reduced without significantly reducing
accuracy?
• Is there a single or are there multiple
hydrogeologic layers to be simulated?
• Is (are) the hydrogeologic layer(s) of
constant or variable thickness spatially?
• Does the model simulate dispersion?
• Does the model simulate sorption?
• Does the model simulate first, second-
order, or other-order decay?
• Does the model simulate density effects
related to changes in temperature and
concentration?
What do the results of a site-
specific fate and transport analy-
sis mean?
A site-specific analysis should, at a mini-
mum, provide estimated leachate concentra-
tions at specified downgradient points for a
proposed liner design. For landfills, surface
impoundments, and waste piles, compare
these concentrations to appropriate MCLs,
health-based standards, and/or state stan-
dards. For land application units, if a waste
leachate concentration is below the values
specified by the state, land application may be
appropriate. Conversely, if a leachate concen-
7A-25
-------
• Pro;
Protecting Ground Water—Assessing Risk Section
tration is above state-specified values, land
application may not be, protective of the
ground water.
A well-executed, site-specific analysis can
be a useful instrument to anticipate and avoid
potential risks. A poorly-executed, site-spe-
cific analysis, however, could over-or under-
emphasize risks, possibly leading to adverse
human health and environmental effects, or
costly cleanup liability, or could overempha-
size risks, possibly leading to the unnecessary
expenditure of limited resources. Share the
model, if possible, and the results of the final
analyses, including input and output parame-
ters-and key assumptions, with key stake-
holders. The chapter on building partner-
ships provides a more detailed description of
activities to keep the public informed and
involved.
Table 6 provides a brief description of five
ground-water fate and transport models.
These descriptions are included in EPA's
Ground-Water Modeling Compendium (see
Resources at the end of this chapter for a
complete citation).
WhataresomeijseMresoiircesforselecting
a ground-water fete and transport model?
The following list of EPA resources can help
select an appropriate model.
• Ground Water Modeling Compendium,
Second Edition (EPA 1994)
• Assessment Framework for Ground-
Water Modeling Applications (EPA 1994)
• Selection Criteria for Mathematical
Models Used in Exposure Assessments:
Ground-Water Models (EPA 1988c).
• Superfund Exposure Assessment Manual
(SEAM—EPA 1988b).
• Exposure Assessment Methods
Handbook (EPA 19890.
• EPA's Center for Exposure Assessment
Modeling (CEAM—Environmental
Research Laboratory; Athens, Georgia).
• EPA regional offices.
7A-26
-------
Protecting Ground Water—-Assessing Risk Section
ASTM Ground-Water Modeling Standards
The American Society for Testing and Materials (ASTM), Section D-
18.21.10 concerns subsurface fluid-flow (ground-water) modeling.
The ASTM ground-water modeling section is one of several task
groups funded under a cooperative agreement between USGS and
EPA to develop consensus standards for the environmental industry
and keep the modeling community informed as to the progress-;
being made in development of modeling standards.
The standards being developed by D-18,21,10 are "guides" in
ASTM tenninoiogy, which means that the content is analogous to.
that of EPA guidance documents. The ASTM modeling guides are
intended to document the state-of-the-science related to various
topics in subsurface modeling. . : • ;: ,.-..•'.•"---
The foEowing standards have been developed by D-i8;2UO and
: passed by ASTM. They can be purchased from ASTM by;callmg /
610 832-9585- Seethe ASTM web site to. order ,
or browse for publications. . . : :-'
D-5447 Guide for Application of a Ground-Water Flow Model to a
Site-Specific Problem .: ' ;
D-5490, Guide for. Comparing Ground-Water Flow-Model:
Simulations to Site- Specific Information
D-5609 Guide for Defining Boundary Conditions in Ground-Water
Flow Modeling ' __ • ... . /
D-5610 Guide for Defining Initial Conditions in Ground-Water
Flow Modeling : '•'''.'-..-''
D-5611-Guide for Conducting a Sensitivity Analysis for a Ground-
' Water Flow Model Application ,•
, D-5718 Guide for Documenting a Ground-Water Flow Model
Application .
D-5719 Guide to Simulation of Subsurface Air Flow Using
. Ground-Water Flow Modeling Codes .
D-5880 Guide for Subsurface Flow and Transport Modeling
.D-5981 Guide for Calibrating a Ground-Water How Model
Application . •-••...,.
A compilation of most of the current modeling and aquifer testing
standards also can be purchased. The tide of the publication is
ASTM Standards on Analysis of Hydrologic Parameters and Ground
Water Modeling, publication number 03-418096-38. For more
information by e-mail, contact servke@astm.org.
7A-27
-------
Protecting Ground Water—Assessing Risk Section
Model Name
Table 6.
Example Site-Specific, Ground-Water Fate and Transport Models
Description
AT123D
AT123D is a generalized analytical transient, one- two-, and/or three-
dimensional computer code developed for estimating the transport of
chemicals in a confined aquifer system with uniform flow. The model
handles various source configurations (including point source, line source,
and areal source) and release characteristics. The transport mechanisms
include advection, longitudinal as well as horizontal and vertical trans
verse hydro-dynamic dispersion, diffusion, linear adsorption, and first-
order decay/degeneration and chemical losses to the atmosphere. The
model calculates concentration distribution in space and time using
Green's function.
The model was developed by Oak Ridge National Laboratory. For more
information and/or to obtain a copy of this model, contact:
International Ground Water Modeling Center (IGWMC)
Colorado School of Mines
Golden, Colorado 80401-1887
Phone: 303 273-3103 (General Questions, Sales)
Phone: 303 273-3105 (Technical Support)
Internet:
-------
Protecting Ground Water—-Assessing Risk Section
Table 6.
Example Site-Specific, Ground-Water Fate and Transport Models (cont.)
Model Name
MODFLOW
Description
MODFLOW is a model for steady state and transient simulation of two-
dimensional, quasi three-dimensional, and fully three-dimensional saturat-
ed flow problems in confined and unconfined aquifers. It calculates flow
rates and water balances. The model includes flow towards wells, dirough
riverbeds, and into drains.
For more information and/or to obtain a copy of this model, contact
IGWMC using the information described above.
MT3D
MT3D is a three-dimensional contaminant transport model using a hybrid
method of characteristics. Two numerical techniques are provided for the
solution of the advective-dispersive reactive solute transport equation: the
method of characteristics (MOC) and die modified method of characteris-
tics (MMOC). The MMOC method overcomes many of the traditional
problems with MOC, especially in 3D simulations, by directly tracking
nodal points backwards in time and by using interpolation techniques.
MT3D selectively uses the MOC or the MMOC technique dependent on
the problem at hand. The transport model is so structured that it can be
used in conjunction widi any block-centered finite difference flow model
such as the USGS MODFLOW model.
The model was developed by S.S. Papadopulos & Associates, Inc. For
more information and/or to obtain a copy of this model, contact:
Center for Subsurface Modeling Support
R.S. Kerr Environmental Research Laboratory
U.S. EPA
P.O. Box 1198
Ada, OK 74820
Phone: 405 332-8800
RANDOM WALK
RANDOM WALK/TRANS is a numerical model to simulate two-dimen-
sional steady or transient flow and transport problems in aquifers under
water table and/or confined or leaky confined conditions. The flow is
solved using a finite difference approach and the iterative alternating direc-
tion implicit method. The advective transport is solved with a particle-in-
cell method, while the dispersion is analyzed with the random walk
method.
This model was developed by Illinois State Water Survey. For more infor-
mation and/or to obtain a copy of this model, contact IGWMC using die
information described above.
7A-29
-------
Protecting Ground Water—Assessing Risk Section
D
D
D
D
D
Action Items for Assessing Risks to Ground Water
Review the risk characterization tools recommended by this chapter.
Characterize the waste in accordance with the recommendations of the chapter on charac-
terizing waste. Obtain leachate concentrations for all relevant waste constituents.
Understand and use the Tier 1: National Evaluation lookup tables, if appropriate.
If appropriate, understand and use the Tier 2: Location-adjusted Evaluation.
If appropriate, understand and use a site-specific ground-water fate and transport model.
7A-30
-------
Protecting Ground Water—Assessing Risk Section
Resources
American Petroleum Institute. Graphical Approach for Determining Site-Specific Dilution-Attenuation
Factors: Technical Background Document and User Manual. API Publication 4659.
ASTM. 1996. ASTM Standards on Analysis of Hydrologic Parameters and Ground Water Modeling,
Publication Number 03-418096-38.
ASTM. 1993. D-5447 Guide for Application of a Ground-Water Flow Model to a Site-Specific
Problem.
ASTM. 1993. D-5490 Guide for Comparing Ground-Water Flow Model Simulations to Site- Specific
Information.
ASTM. 1994. D-5609 Guide for Defining Boundary Conditions in Ground-Water Flow Modeling.
ASTM. 1994. D-5610 Guide for Defining Initial Conditions in Ground-Water Flow Modeling.
ASTM. 1994. D-5611 Guide for Conducting a Sensitivity Analysis for a Ground-Water Flow Model
Application.
ASTM. 1994. D-5718 Guide for Documenting a Ground-Water Flow Model Application.
ASTM. 1994. D-5719 Guide to Simulation of Subsurface Air Flow Using Ground-Water Flow
Modeling Codes.
ASTM. 1995. D-5880 Guide for Subsurface Flow and Transport Modeling.
ASTM. 1996. D-5981 Guide for Calibrating a Ground-Water Flow Model Application.
Bagchi, A. 1994. Design, Construction, and Monitoring of Landfills.
Berner, E. K. and R. Berner. 1987. The Global Water Cycle: Geochemistry and Environment.
Bonaparte, R., J.P. Giraud, and B.A. Gross. 1989. "Rates of Leakage Through Landfill Liners,"
Proceedings of Geosynthetic '89 Conference, Volume 1.
7A-31
-------
Protecting Ground Water—Assessing Risk Section
Resources (cont.)
Boulding, R. 1995. Soil, Vadose Zone, and Ground-Water Contamination: Assessment,
Prevention, and Remediation.
Giroud, J.R, K. Badu-Tweneboah. 1992. "Rate of Leakage Through a Composite Liner Due to
Geomembrane Defects," Journal of Geotextiles and Geomembranes, Volume 11.
Giroud, J.P., and R. Bonaparte. 1989. "Leakage Through Liners Constructed with
Geomembranes: Part I Geomembrane Liners," Journal of Geotextiles and Geomembranes,
Volume 8.
Giroud, J.P., and R. Bonaparte. 1989. "Leakage Through Liners Constructed with '
Geomembranes: Part II Composite Liners," Journal of Geotextiles and Geomembranes, Volume 8.
Lee, C. 1992. Environmental Engineering Dictionary, 2d. Ed.
Sharma, H., and S. Lewis. 1994. Waste Containment Systems, Waste Stabilization, and
Landfills.
Speidel, D,, L. Ruedisili, and A. Agnew. 1988. Perspectives on Water: Uses and Abuses.
U.S. EPA. 1998. Industrial Waste Management Evaluation Model Technical Background
Document.
U.S. EPA. 1998. The User's Guide for the Industrial Waste Management Evaluation Model.
U.S. EPA. 1996. Composite Model for Leachate Migration with Transformation Products.
U.S. EPA. 1996. EPACMTP Background Document.
U.S. EPA. 1996. EPACMTP Background Document for the Finite Source Methodology.
U.S. EPA. 1994. Assessment Framework for Ground-Water Modeling Applications. EPA500-B-
94-003.
U.S. EPA 1994. Ground Water Modeling Compendium, Second Edition. EPA500-B-94-003.
7A-32
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Protecting Ground Water—Assessing Bisk Section
Resources (cont.)
U.S. EPA. 1991. Seminar Publication: Site Characterization for Subsurface Remediation. EPA625-4-
91-026.
U.S. EPA. 1989. Exposure Assessment Methods Handbook.
U.S. EPA. 1988. Selection Criteria For Mathematical Models Used In Exposure Assessments:
Ground-water Models. EPA600-8-88-075.
U.S. EPA. 1988. Superfund Exposure Assessment Manual.
7A-33
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-------
Part IV
Protecting Ground Water
Chapter 7: Section B
Designing and Installing Liners
Technical Considerations for Surface
Impoundments, Landfills, and Waste Piles
-------
Contents
I. In-Situ Soil Liners ^ ; 7B'1
II. Single Liners ! ;7B'2
A. Compacted Clay Liners ; 7B~2
B. Geomembranes or Flexible Membrane Liners 7B-10
C Geosynthetic Clay Liners t 7B~17
III. Composite Liners • 7B~22
IV. Double Liners (Primary and Secondary Lined Systems) , 7B-23
V. Leachate Collection and Leak Detection Systems ; 7B-24
A. Leachate Collection System .••.-••••. ••••• —7B-25
B. Leak Detection System 7B-29
C. Leachate Treatment System ! 7B-29
VI. Construction Quality Assurance and Quality Control • 7B-30
A. Compacted Clay Liner Quality Assurance and Quality Control 7B-32
B. Geomembrane Liner Quality Assurance and Quality Control , 7B-33
C. Geosynthetic Clay Liner Quality Assurance and Quality Control 7B-34
D. Leachate Collection System Quality Assurance and Quality Control 7B-34
Action Items for Lined Units (Landfills, Waste Piles, and Surface Impoundments) 7B-36
Resources r •7B-37
Figures:
Figure 1: Water Content for Achieving a Specific Density 7B-7
Figure 2: types of Footed Rollers • 7B~9
Figure3: Four Variations of GCL Bonding Methods , 7B-19
Figure 4: Typical Leachate Collection System , 7B-25
Figure 5: Typical Geonet Configuration • 7B-27
-------
Protecting Ground Water—Designing and Installing Liners
Designing and Installing Liners—Technical
Considerations for Surface Impoundments,
Landfills, arid Waste Piles
Employ liner systems where needed to protect ground water
from contamination. Select from clay liners, synthetic liners,
composite liners, leachate collection systems, and leak detec-
tion systems as appropriate. Consider technical issues carefully
to ensure that the liner system will function as designed.
Once risk has been characterized
and the most appropriate liner
system chosen, unit design can
proceed. A critical part of this
design for landfills, waste piles,
and surface impoundments is the liner system.
The liner system recommendations in this guid-
ance do not apply to land application units,
since such operations generally do not include a
liner system as part of their design. (For design
of land application units, refer to the discussion
in designing a land application program section
of this chapter.) During liner system design,
work with state agencies to ensure considera-
tion of any applicable liner system require-
ments, recommendations, or standard practices
the state may have. In this part of the chapter,
sections I though IV discuss four liner
options—no liner/in-situ soils, single liner,
composite liner, and double liner. Section V
covers leachate collection and leak detection
systems, and section VI discusses construction
quality assurance and quality control.
I. In-Situ Soil
Liners
For the purpose of this guidance, in-situ
soil liners refer to simple, excavated areas or
impoundments, without any additional engi-
neering controls. The ability of natural soils to
reduce the concentration of constituent levels
through dilution and attenuation may provide
sufficient protection when the initial con-
stituent levels in the waste stream are very low,
when the wastes are inert, or when the hydro-
geologic setting affords sufficient protection.
What are the recommendations
for in-situ soils?
The soil below and adjacent to a waste man-
agement unit should be suitable for construc-
tion. It should provide a firm foundation for
the waste. Due to the low risk associated with
wastes being managed in these units, no liner
may be necessary; however, it is still helpful to
review the recommended location considera-
tions and operating practices for the unit.
7B-1
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Protecting Ground Water—Designing and Installing Liners
What technical issues should be
considered with the use of in-situ
soils?
In units using in-situ natural soils, con-
struction and design of an engineered liner
will not be necessary; however, there are still
technical concerns to consider. These include
the following:
• The stability of foundation soils;
• The compatibility of the waste with native
soils;
• The location where the unit will be sited;
and
• The potential to recompact existing soils.
Potential instability can occur in the founda-
tion soil, if its-load-bearing capacity and resis-
tance to movement or consolidation are insuf-
ficient to support the waste. The ground-water
table or a weak soil layer also may influence
the stability of the unit. Take measures, such
as designing maximum slopes, to avoid slope
failure during construction and operation of
the waste management unit. Most soil slopes
are stable at a 3:1 horizontal to vertical incli-
nation. Follow common sense operating prac-
tices and ensure that any wastes to be man-
aged on in-situ soils will not inappropriately
interact with the soils. When using in-situ
soils, refer to the chapter on considering the
site. Selecting an appropriate location will be
of increased importance, since the added bar-
rier of an engineered liner will not present.
Because in-situ soil may have non-homoge-
neous material, root holes, and cracks, its per-
formance can be improved by scarifying and
compacting the top portion of the in-situ nat-
ural soils.
II. Single Liners
If the risk evaluation recommended the use
of a single liner, determine the type of single
liner system most appropriate for the site. The
discussion below addresses three types of sin-
gle liner systems: compacted clay liners,
geomembrane liners, and geosynthetic clay
liners. Determine which material, or combina-
tion of materials, protects human health and
the environment based on the cost of these
materials for the unit.1
A. Compacted Clay Liners
A compacted clay liner can serve as a single
liner or as part of a composite or double liner
system. Compacted clay liners are composed
of natural mineral materials (natural soils),
bentonite-soil blends, and other materials
placed and compacted in layers called lifts. If
natural soils at the site contain a significant
quantity of clay, then liner materials may be
excavated from onsite, locations known as bor-
row pits. Alternatively, if on-site soils do not
contain sufficient clay, clay materials can be
hauled from off-site sources, often referred to
as commercial pits.
Compacted clay liners can be designed to
work effectively as hydraulic barriers. To
ensure that compacted clay liners are well
constructed and perform as they are designed,
implement effective quality control methods
emphasizing soil investigations and construc-
tion practices. Three objectives of quality
assurance and quality control for compacted
soil liners are to ensure that (1) selected liner
materials are suitable, (2) liner materials are
properly placed and compacted, and (3) the
completed liner is properly protected before,
during, and after construction. Quality assur-
ance and quality control are discussed in
greater detail in section VI.
7B-2
'Many industry and trade periodicals, such as Waste Age, MSW Management, Solid Waste Technologies, and
World Wastes, have articles on liner types and their corresponding costs, as well as advertisements and
lists of vendors.
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Protecting Ground Water—Designing and Installing Liners
What are the thickness and
hydraulic conductivity recom-
mendations for compacted clay
liners?
Compacted clay liners should be at least 2
feet thick and have a maximum hydraulic
conductivity of 1 x 10'7 cm/sec (4 x 10"8
in/sec). Hydraulic conductivity refers to the
degree of ease with which a fluid can flow
through a material. A low hydraulic conduc-
tivity will help minimize leachate migration
out of a unit. Designing a compacted clay
liner with a thickness ranging from 2 to 5 feet
will help ensure that the liner meets desired
hydraulic conductivity standards and will
also minimize leachate migration as a result
of any cracks or imperfections present in the
liner. Thicker compacted clay liners provide
additional time to minimize leachate migra-
tion prior to the clay becoming saturated.
What issues should be consid-
ered in the design of a compact-
ed clay liner?
The first step in designing a compacted
clay liner is selecting the clay material. The
quality and properties of the material will
influence the performance of the liner. The
most common type of compacted soil is one
that is constructed from naturally occurring
soils that contain a significant quantity of
clay. Such soils are usually classified as CL,
CH, or SC in the Unified Soil Classification
System (USCS). Some of the factors to con-
sider in choosing a soil include soil proper-
ties, interaction with wastes, and test results
for potentially available materials.
Soft Properties
Minimizing hydraulic conductivity is the
primary goal in constructing a soil liner.
Consider water content, plasticity characteris-
tics, percent fines, and percent gravel, as
these properties affect the soil's ability to
achieve a specified hydraulic conductivity.
Hydraulic Conductivity. Select compacted
clay liner materials so that remolding and
compacting of the materials will produce a
low hydraulic conductivity. Factors influ-
encing the hydraulic conductivity at a par-
ticular site include: the degree of com-
paction, compaction method, type of clay
material used, soil moisture content, and
density of the soil during liner construc-
tion. The hydraulic conductivity of a soil
also depends on the viscosity and density
of the fluid flowing through it. Consider
measuring hydraulic conductivity using
methods such as American Society of
Testing and Materials (ASTM) D-5084.2
Water Content. Water content refers to the
amount of liquid, or free water, contained
in a given amount of material. Measuring
water content can help determine whether
a clay material needs preprocessing, such
as moisture adjustment or soil amend-
ments, to yield a specified density or
hydraulic conductivity. Compaction curves
can be used to depict moisture and density
relationships, using either ASTM D-698 or
ASTM D-1557, the standard or modified
Proctor test methods, depending on the
compaction equipment used and the
degree of firmness in the foundation mate-
rials.3 The critical relationship between
clay soil moisture content and density is
explained thoroughly in Chapter 2 of
EPA's 1993 technical guidance document
Quality Assurance and Quality Control for
Waste Containment Facilities (EPA600-R-93-
182).
2ASTM D-5084, Standard Test Method for Measurement of Hydraulic Conductivity of Saturated Porous
Materials Using a Flexible Wall Permeameter.
3ASTM D-698, Test Method for Laboratory Compaction Characteristics of Soil Using Standard Effort (12 400 ft-
Ibf/ft3 (600 kN-m/m3)).
7B-3
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Protecting Ground Water—Designing and Installing Liners
Plasticity Characteristics. Plasticity charac-
teristics describe a material's ability to
behave as a plastic or moldable material.
Soils containing clay are generally catego-
rized as plastic. Soils that do not contain
clay are non-plastic and typically consid-
ered unsuitable materials for compacted
clay liners, unless soil amendments such
as bentonite clay are introduced.
Plasticity characteristics are quantified by
three parameters: liquid limit, plastic limit,
and plasticity index. The liquid limit is
defined as the minimum moisture content
(in percent of oven-dried weight) at which
a soil-water mixture can flow. The plastic
limit is the minimum moisture content at
which a soil can be molded. The plasticity
index is defined as the liquid limit minus
the plastic limit and defines the range of
moisture content over which a soil
exhibits plastic behavior. When soils with
high plastic limits are too dry during
placement, they tend to form clods, or
hardened clumps, that are difficult to
break down during compaction. As a
result, preferential pathways may form
around these clumps allowing leachate to
flow through the material at a higher rate.
Soil plasticity indices typically range from
10 percent to 30 percent. Soils with a plas-
ticity index greater than 30 percent are
cohesive, sticky, and difficult to work with
in the field. Common testing methods for
plasticity characteristics include the meth-
ods specified in ASTM D-4318, also
known as Atterberg limits tests.4
Percent Fines and Percent Gravel. Typical
soil liner materials contain at least 30 per-
cent fines and may contain up to 50 per-
cent gravel, by weight. Common testing
methods for percent fines and percent
gravel are specified in ASTM D-422, also
referred to as grain size distribution tests.3
Fines refer to silt and clay-sized particles.
Soils with less than 30 percent fines may
be worked to obtain hydraulic conductivi-
ties below 1 x lO'7 cm/sec-(4 x 10'8
in./sec), but use of these soils requires
more careful construction practices.
Gravel is defined as particles unable to
pass through the openings of a Number 4
sieve, which has an opening size equal to
4.76 mm (0.2 in.). Although gravel itself
has a high hydraulic conductivity, relative-
ly large amounts of gravel, up to 50 per-
cent by weight, can be uniformly mixed
with clay materials without significantly
increasing the hydraulic conductivity of
the material. Clay materials fill voids creat-
ed between gravel particles, thereby creat-
ing a gravel-clay mixture with a low
hydraulic conductivity. Creating a uniform
mixture of clay and gravel, where clay can
fill in gaps, is more critical than the actual
gravel content of the mixture, as long as
the percent gravel in a compacted clay
mixture remains below 50 percent.
Pay close attention to the percent gravel in
cases where a compacted clay liner func-
tions as a bottom layer to a geosynthetic,
as gravel can cause puncturing in geosyn-
thetic materials. Controlling the maximum
particle size and angularity of the gravel
should help prevent puncturing, as well as
prevent gravel from creating preferential
flow paths. Similar to gravel, soil particles
or rock fragments also can create preferen-
tial flow paths. To help prevent the devel-
opment of preferential pathways and an
increased hydraulic conductivity, use soil
liner materials where the soil particles and
rock fragments are less than 3/4 inch in
diameter.
7B-4
'ASTM D-4318, Standard Test Method for Liquid Limit, Plastic Limit, and Plasticity Index of Soils.
'ASTM D-422, Standard Test Method for Particle-Size Analysis of Soils. \
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Protecting Ground Water—Designing and Installing Liners
Interactions With Waste
Waste placed in a unit may interact with
compacted clay liner materials, thereby influ-
encing soil properties such as hydraulic con-
ductivity and permeability. Two ways that
waste materials can influence the hydraulic
conductivity of the liner materials are
through dissolution of soil minerals and
changes in clay structure. Soil minerals can
be dissolved, or reduced to liquid form, as a
result of interaction with acids and bases. For
example, aluminum and iron in the soil may
be dissolved by acids, and silica may be dis-
solved by bases. While some plugging of soil
pores by dissolved minerals may lower
hydraulic conductivity in the short term, the
creation of piping and channels over time
may lead to an increased hydraulic conduc-
tivity in the long term. The interaction of
waste and clay materials may also cause the
creation of positive ions, or cations. The pres-
ence of cations such as sodium, potassium,
calcium, and magnesium may change the clay
structure, thereby influencing the hydraulic
conductivity of the liner. Depending on the
cation type and the clay mineral, an increased
presence of such cations can cause the clay
minerals to form clusters and increase the
permeability of the clay. Therefore, before
selecting a compacted clay liner material,
develop a good understanding of the compo-
sition of the waste that will be placed in the
waste management unit. EPA's Method 9100,
in publication SW-846, measures the
hydraulic conductivity of soil samples before
and after exposure to permeants.6
Locating and Testing Material
Although the selection process for com-
pacted clay liner construction materials may
vary from project to project, some common
material selection steps include locating and
testing materials at a potential borrow or
commercial pit before construction, and
observing and testing material performance
throughout construction. First, investigate a
potential borrow or commercial pit to deter-
mine the volume of materials available. In
addition, test a representative sample of soil
to determine material properties such as plas-
ticity characteristics, percent gravel, and per-
cent fines. To confirm the suitability of the
materials once construction begins, consider
requesting that representative samples from
the materials in the borrow or commercial pit
be tested periodically after work has started.
Material selection steps will vary, depend-
ing on the origin of the materials for the pro-
ject. For example, if a commercial pit pro-
vides the materials, locating an appropriate
on-site borrow pit is no longer necessary. In
addition to the tests performed on the materi-
al, a qualified inspector should make visual
observations throughout the construction
process to ensure that harmful materials,
such as stones or other large matter, are not
present in the liner material.
What issues should be consid-
ered in the construction of a
liner and the operation of a
unit?
Develop test pads to demonstrate con-
struction techniques and material perfor-
mance on a small scale. During unit construc-
tion and operation, some additional factors
influencing the performance of the liner
include: preprocessing, subgrade preparation,
method of compaction, and protection
against desiccation and cracking. Repeat all
the steps, from preprocessing through protec-
tion against desiccation and cracking, for
each lift, or layer of soil.
6SW-846, Test Methods for Evaluating Solid Waste: Physical/Chemical Methods.
7B-5
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Protecting Ground Water—Designing and Instating Liners
Test Pads
Preparing a test pad for the compacted clay
liner helps verify that the materials and meth-
ods proposed will yield a liner that meets the
desired hydraulic conductivity. A test pad also
provides an opportunity to demonstrate the
performance of alternative materials or meth-
ods of construction. A test pad should be con-
structed with the soil liner materials proposed
for a particular project, using the same prepro-
cessing procedures, compaction equipment,
and construction practices proposed for the
actual liner. A complete discussion of test pads
(covering dimensions, materials, and construc-
tion) can be found in Chapter 2 of EPA's 1993
technical guidance document Quality Assurance
and Quality Control for Waste Containment
Facilities (EPA600-R-93-182). A discussion of
commonly used methods to measure in-situ
hydraulic conductivity is also contained in that
chapter.
Preprocessing
Although some liner materials may be
ready for use in construction immediately
after they are excavated, many materials will
require some degree of preprocessing.
Preprocessing methods include: water content
adjustment, removal of oversized particles,
pulverization of any clumps, homogenization
of the soils, and introduction of additives,
such as bentonite.
Water Content Adjustment. For natural
soils, the degree of saturation of the soil
liner at the time of compaction, known as
molding water content, influences the
engineering properties of the compacted
material. Soils compacted at water contents
less than optimum tend to have a relatively
high hydraulic conductivity. Soils compact-
ed at water contents greater than optimum
tend to have low hydraulic conductivity
and low strength.
Proper soil water content revolves around
achieving a minimum:dry density, which is
expressed as a percentage of the soil's max-
imum dry density. The minimum dry den-
sity typically falls in the range of 90-95
percent of the soil's maximum dry density
value. From the minimum dry density
range, the required water content range
can be calculated, as shown in Figure 1. In
this example the soil has a maximum dry
density of 115 Ib/cu ft. Based upon a
required minimum dry density value of 90
percent of maximum dry density, which is
equal to 103.5 Ib/cu ft., the required water
content ranges from 10 to 28 percent.
It is less problematic to compact clay soil at
the lower end of the required water content
range because it is easier to add water to the
clay soil than to remove it. Thus, if precipi-
tation occurs during construction of a site
which is being placed at the lower end of
the required water content range, the addi-
tional water may not result in a soil water
content greater than the required range.
Conversely, if the site is being placed at the
upper end of the range, for example at 25
percent, any additional moisture will be
excessive, resulting in water content over 28
percent and making the 90 percent maxi-
mum dry density unattainable. Under such
conditions constractiqn should halt while
the soil is aerated and excess moisture is
allowed to evaporate.
Removal of Oversized Particles.
Preprocessing clay materials, to remove
cobbles or large stones that exceed the
maximum allowable particle size, can
improve the soil's compactibility and pro-
tect any adjacent geotnembrane from punc-
ture. A recommended maximum allowable
particle size is less than 3/4 inch for com-
paction considerations. If a geomembrane
will be placed over the compacted clay,
7B-6
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Protecting Ground Water—Designing and Installing Liners
Figure 1.
Water Content for Achieving a Specific Density
sS 100 -
o
fc-
o
Water Conjent (w>,%
Source: U.S. EPA. 1988. Lining of Waste Containment and Other
Impoundment Facilities. EPA600-2-88-052.
only the upper lift of clay needs to address
concerns regarding puncture resistance.
Observation by quality assurance and qual-
ity control personnel is the most effective
method to identify areas where oversized
particles need to be removed. Cobbles and
stones are not the only materials that can
interfere with compactive efforts. Chunks
of dry, hard clay, also known as clods, often
need to be broken into smaller pieces to be
properly hydrated, remolded, and com-
pacted. In wet clay, clods are less of a con-
cern since wet clods can often be remolded
with a reasonable compactive effort.
Soil Amendments. If the
soils at a unit do not have
a sufficient percentage of
clay, a common practice is
to blend bentonite with
them to reduce the
hydraulic conductivity.
Bentonite is a clay mineral
that expands when it
comes into contact with
water. Relatively small
amounts of bentonite, on
the order of 5 to 10 per-
cent, can be added to
sand or other noncohe-
sive soils to increase the
cohesion of the material
and reduce hydraulic con-
ductivity.
Sodium bentonite is a
common additive used to
amend soils. However,
this additive is vulnerable
to degradation as a result
of contact with certain
chemicals and waste
leachates. Calcium ben-
tonite, a more permeable
material than sodium
bentonite, is another common additive used
to amend soils. Approximately twice as
much calcium bentonite is needed to
achieve a hydraulic conductivity compara-
ble to that of sodium bentonite. Amended
soil mixtures generally require mixing in a
pug mill, cement mixer, or other mixing
equipment that allows water to be added
during the mixing process. Throughout the
mixing and placement processes, water con-
tent, bentonite content, and particle distrib-
ution need to be controlled. Other materials
that can be used as soil additives include
lime cement and other clay minerals, such
as atapulgite. It may be difficult to mix
7B-7
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Protecting Ground Water—Designing and Instating Liners
additives thoroughly with cohesive soils, or
clays; the resultant mixture may not achieve
the desired level of hydraulic conductivity
throughout the entire liner.
Subgrade Preparation
Ensure that the subgrade on which a com-
pacted clay liner will be constructed is prop-
erly prepared. When a compacted clay liner
is the lowest component of a liner system, the
subgrade consists of native soil or rock.
Subgrade preparation for these systems
involves compacting the native soil to remove
any soft spots and adding water to or remov-
ing water from the native soil to obtain a
specified firmness. Alternatively, in some
cases, the compacted clay liner can be placed
on top of a geosynthetic material, such as a
geotextile. In such cases, subgrade prepara-
tion involves ensuring the smoothness of the
geosynthetic on which the clay liner will be
placed and the conformity of the geosynthetic
material to the underlying material.
Compaction
The main purpose of compaction is to
densify the clay materials by breaking and
remolding clods of material into a uniform
mass. Since amended soils usually do not
develop clumps, the primary objective of
compaction for such materials is to increase
the material's density. Proper compaction of
liner materials is essential to ensure that a
compacted clay liner meets specified
hydraulic conductivity standards. Factors
influencing the effectiveness of compaction
efforts include: the type of equipment select-
ed, the number of passes made over the
materials by such equipment, the lift thick-
ness, and the bonding between the lifts.
Molding water content, described earlier
under preprocessing, is another factor influ-
encing the effectiveness of compaction.
Type of Equipment. Factors to consider when
selecting compaction equipment include: the
type and weight of the compactor, the charac-
teristics of any feet on the drum, and the
weight of the roller per unit length of
drummed surface. Heavy, compactors, weigh-
ing more than 50,000 pounds, with feet long
enough to penetrate a loose lift of soil, are
often the best types of compactor for clay lin-
ers. For bentonite-soil mixtures, a footed
roller may not be appropriate. For these mix-
tures, where densification of the material is
more important than kneading or remolding
it to meet low hydraulic conductivity specifi-
cations, a smooth-drum roller or a rubber-
tired roller may produce better results. Figure
2 depicts two types of footed rollers, a fully
penetrating footed roller and a partially-pene-
trating footed roller.
For placement of liners on side slopes,
consider the angle and length of the slope.
Placing continuous lifts qn a gradually
inclined slope will provide better continuity
between the bottom and sidewalls of the
liner. Since continuous lifts may be impossi-
ble to construct on steeper slopes due to the
difficulties of operating heavy compaction
equipment on these slopes, materials may
need to be placed and compacted in horizon-
tal lifts. When sidewalls are compacted hori-
zontally, it is important to avoid creating
seepage planes, by securely connecting the
edges of the horizontal lift with the bottom of
the liner. Because the lift needs to be wide
enough to accommodate compaction equip-
ment, the thickness of the horizontal lift is
often greater than the thickness specified, in
the design. In such cases, consider trimming
soil material from the constructed side slopes
and sealing the trimmed surface using a
sealed drum roller.
7B-8
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Protecting Ground Water—Designing and Installing Liners
Figure 2. Types of Footer Rollers
Rotter with
Partly
Penetrating
Faet
Roller with
Fully Penetrating
Feet
Loose lift of So8
Fully Ptrwtreang Fwt on Holltf
Compact Saw oj New, IAOM Lift
of Soil Into Surfac* et OW. Pravtoudy
Parity Pgn«ratfng F«et on Roltor Do
Not Exttnd to BOM of N«w, LOOM
Uftef Soil and Do Not Compact Now
SJlintoSudac*ofOldU1l
Source: U.S. EPA. 1993. Technical Guidance Document: Quality Assurance and Quality Control
For Waste Containment Facilities. EPA600-R-93-182.
It is common for contractors to use several
different types of compaction equipment
during liner construction. Initial lifts may
need the use of a footed roller to fully pen-
etrate a loose lift. Final lifts also may need
the use of a footed roller for compaction,
however, they may be formed better by
using a smooth roller after the lift has been
compacted to smooth the surface of the lift
in preparation for placement of an overly-
ing geomembrane.
Number, of Passes. The number of passes
made by a compactor over clay materials
can influence the overall hydraulic con-
ductivity of the liner. The minimum num-
ber of passes that is reasonable depends on
a variety of site-specific factors and cannot
be generalized. In some cases, where a
minimum coverage is specified, it may be
possible to calculate the minimum number
of passes to meet such a specification. At
least 5 to 15 passes with a compactor over
a given point are usually necessary to
remold and compact clay liner materials
thoroughly.
An equipment pass may be defined as one
pass of the compaction equipment or as
one pass of a drum over a given area of
soil. Clearly define what is meant by a pass
in any quality assurance or quality control
plans. It does not matter which definition
is agreed upon, as long as the definition is
used consistently throughout the project.
Lift Thickness. Determine the appropriate
thickness (as measured before compaction)
of each of the several lifts that will make
up the clay liner. The initial thickness of a
loose lift will affect the compactive effort
needed to reach the lower portions of the
lift. Thinner lifts allow compactive efforts
to reach the bottom of a lift and provide
greater assurance that compaction will be
sufficient to allow homogenous bonding -
between subsequent lifts. Loose lift thick-
nesses typically range between 13 and 25
7B-9
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Protecting Ground Water—Designing and Installing Liners
cm (5 and 10 in.). Factors influencing lift
thickness are: soil characteristics, com-
paction equipment, firmness of the foun-
dation materials, and the anticipated com-
paction necessary to meet hydraulic con-
ductivity requirements.
Bonding Between lifts. Since it is
inevitable that some zones of higher and
lower hydraulic conductivity, also known
as preferential pathways, will be present
within each lift, lifts should be joined or
bonded in a way that minimizes extending
these zones or pathways between lifts. If
good bonding is achieved, the preferential
pathways will be truncated by the bonded
zone between the lifts. At least two recom-
mended methods exist for preparing prop-
er bonds. The first method involves knead-
ing, or blending the new lift with the pre-
viously compacted lift using a footed roller.
Using a roller with feet long enough to
fully penetrate through the top lift and
knead the previous lift improves the quali-
ty of the bond. A second method involves
using a disc harrow or similar equipment
to scarify, or roughen, and wet the top inch
of the recently placed lift, prior to placing
the next lift.
Protection Against Desiccation and Cracking
Consider how to protect compacted clay
liners against desiccation and freezing during
and after construction. Protection against des-
iccation is important, because clay soil
shrinks as it dries. Depending on the extent
of shrinkage, it may crack. Deep cracks,
extending through more than one lift, may
cause problems. Measure water content to
determine whether desiccation is occurring.
There are several ways to protect compact-
ed clay liners from desiccation. One preven-
tive measure is to smooth roll the surface
with a steel drummed roller to produce a
thin, dense skin of soil; this layer can help
minimize the movement of water into or out
of the compacted material. Another option is
to wet the clay periodically in a uniform
manner; however, make sure to avoid creat-
ing areas of excessive wetness. A third mea-
sure involves covering compacted clay liner
materials with a sheet of white or clear plastic
or tarp to help prevent against desiccation
and cracking. The cover should be weighted
down with sandbags or other material to
minimize exposure of the underlying materi-
als to air. Using a light-colored plastic will
help prevent overheating, which can dry out
the clay materials. If the clay liner will not be
covered with a geosynthetic, another method
to prevent desiccation involves covering the
clay with a layer of protective cover soil
approximately one foot in thickness.
Protection against freezing is another
important consideration, because freezing
may increase the hydraulic conductivity of a
liner. Avoid construction during freezing
weather. If freezing does occur and the dam-
age affects only a shallow depth, the liner
may be repaired by rerolling the surface. If
deeper freezing occurs, the repairs may be
more complicated. For a general guide to
frost depths, see Figure 1 of the chapter on
performing closure and post-closure care.
B. Geomembranes or
Flexible Membrane
Liners
Geomembranes or flexible membrane lin-
ers are used to contain or prevent waste con-
stituents and leachate from escaping a waste
management unit. Geomembranes are made
by combining one or more plastic polymers
with ingredients such as carbon black, pig-
ments, fillers, plasticizers, processing aids,
crosslinking chemicals, anti-degradants, and
7B-10
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Protecting Ground Water—Designing and Installing Liners
biocides. A wide range of plastic resins are
used for geomembranes, including polyvinyl
chloride (PVC), high density polyethylene
(HDPE), linear low density polyethylene
(LLDPE), and chlorosulfonated polyethylene
(CSPE). Most manufacturers produce
geomembranes through extrusion or calen-
dering. In the extrusion process, a molten
polymer is stretched into a nonreinforced
sheet; extruded geomembranes are usually
made of HDPE and LLDPE. During the calen-
dering process, a heated polymeric com-
pound is passed through a series of rollers. In
this process, a geomembrane may be rein-
forced with a woven fabric or fibers.
Calendered geomembranes are made of PVC
and CSPE.
What are the thickness recom-
mendations for geomembrane
liners?
Geomembranes range in thicknesses from
20 to 120 mil (1 mil = 0.001 in.). A good
design should include a minimum thickness
of 30 mil, except for HDPE liners, which
should have a minimum thickness of 60 mil.
These minimum thicknesses ensure that the
liner material will withstand the stress of con-
struction and the weight load of the waste,
and allow adequate seaming to bind separate
geomembrane panels. Reducing the potential
for tearing or puncture, through proper con-
struction and quality control, is essential for a
geomembrane to perform effectively.
What issues should be consid-
ered in the design of a
geomembrane liner?
Several factors to address in the design
include: determining appropriate material
properties and testing to ensure these proper-
ties are met, understanding how the liner will
interact with the intended waste stream,
accounting for all stresses imposed by the
design, and ensuring adequate friction.
Material Properties and Selection
When designing a geomembrane liner,
examine several properties of the geomem-
brane material in addition to thickness,
including: tensile behavior, tear resistance,
puncture resistance, susceptibility to environ-
mental stress cracks, ultraviolet resistance,
and carbon black content.
Tensile Behavior. Tensile behavior refers to
the tensile strength of a material and its
ability to elongate under strain. Tensile
strength is the ability of a material to resist
pulling stresses without tearing. The tensile
properties of a geomembrane must be suf-
ficient to satisfy the stresses anticipated
during its service life. These stresses
include the self-weight of the geomem-
brane and any down drag caused by waste
settlement on side slope liners.
Puncture and Tear Resistance. Geomem-
brane liners may be subject to tearing during
installation due to high winds or handling.
Puncture resistance is also important to con-
sider since geomembranes are often placed
above or below materials that may have
jagged or angular edges. For example,
geomembranes may be installed above a
granular drainage system that includes gravel.
Susceptibility to Environmental Stress
Cracks. Environmental factors may cause
cracks or failures before a liner is stressed to
its manufactured strength. These imperfec-
tions, referred to as environmental stress
cracks, often occur in areas where a liner
has been scratched or stressed by fatigue.
These cracks can also result in areas where
excess surface wetting agents have been
applied. In surface impoundments, where
7B-11
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Protecting Ground Water—Designing and Installing Liners
the geomembrane liner has greater expo-
sure to the atmosphere and temperature
changes, such exposure may increase the
potential for environmental stress cracking.
Ultraviolet Resistance. Ultraviolet resis-
tance is another factor to consider in the
design of geomembrane liners, especially
in cases where the liner may be exposed to
ultraviolet radiation for prolonged periods
of time. In such cases, which often occur
in surface impoundments, ultraviolet radi-
ation may cause degradation and cracking
in the geomembrane. Adding carbon black
or other additives during the manufactur-
ing process may increase a geomembrane's
ultraviolet resistance.
Interactions With Waste
Since the main purpose of a geomembrane
is to provide a barrier and prevent contami-
nants from penetrating through the geomem-
brane, chemical resistance is a critical consid-
eration. Testing for chemical resistance may
be warranted depending on the type, vol-
umes, and characteristics of waste managed
at a particular unit. An established method
for testing the chemical resistance of
geomembranes, EPA Method 9090, can be
found in SW-846. ASTM has also adopted
standards for testing the chemical compatibil-
ity of various geosynthetics, including
geomembranes, with leachates from waste
management units. ASTM D-5747 provides a
standard for testing the chemical compatibili-
ty of geomembranes.7
Stresses Imposed by Liner Design
A liner design should take into account
the stresses imposed on the liner by the
design configuration. These stresses include:
the differential settlement in foundation soil,
strain requirements at the anchor trench,
strain requirements over long, steep side
slopes, stresses resulting from compaction,
and seismic stresses. Often an anchor trench
designed to secure the geomembrane during
construction is prepared along the perimeter
of a unit cell. This action can help prevent
the geomembrane from slipping down the
interior side slopes. Trench designs should
include a depth of burial sufficient to hold
the specified length of liner. If forces larger
than the tensile strength of the liner are inad-
vertently developed, then the liner could tear.
For this reason, the geomembrane liner
should be allowed to slip or give in the
trench after construction to prevent such
tearing. To help reduce unnecessary stresses
in the liner design, avoid using horizontal
seams. For more information on design
stresses, consult U.S. EPA Geosynthetic
Guidance for Hazardous Waste Landfill Cells
and Surface Impoundments (EPA600-2-87-
097).
Designing/or Adequate Friction
Adequate friction between the geomem-
brane liner and the soil subgrade, as well as
between any geosynthetic components, is
necessary to prevent extehsive slippage or
sloughing on the slopes of a unit. Design
equations for such components should evalu-
ate: (1) the ability of a liner to support its
own weight on side slopes, (2) the ability of a
liner to withstand down-dragging during and
after waste placement, (3) the best anchorage
configuration for the liner, (4) the stability of
soil cover on top of a liner, and (5) the stabil-
ity of other geosynthetic components, such as
geotextiles or geonets, on top of a liner. An
evaluation of these issues may affect the
choice of geomembrane material, polymer
type, fabric reinforcement, thickness, and
texture necessary to achieve the design
requirements.
7ASTM D-5747, Practice for Tests to Evaluate the Chemical Resistance of Geomembranes to Liquids.
7B-12
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Protecting Ground Water—Designing and Installing Liners
What issues should be consid-
ered in the construction of a
geomembrane liner?
When preparing to construct a geomem-
brane liner, plan appropriate shipment and
handling procedures, perform testing prior to
construction, prepare the subgrade, consider
temperature effects, and account for wind
effects. In addition, select a seaming process,
determine a material for and method of back-
filling, and plan for testing during construction.
Shipment, Handling, and Site Storage
Follow quality assurance and quality con-
trol procedures to ensure proper handling of
geomembranes. Different types of geomem-
brane liners require different types of packag-
ing for shipment and storage. Typically a
geomembrane manufacturer will provide spe-
cific instructions outlining the handling, stor-
age, and construction specifications for a
product. In general, HDPE and LLDPE
geomembrane liners are packaged in a roll
form, while PVC and CSPE-R liners (CSPE-R
refers to a CSPE geomembrane liner rein-
forced with a fabric layer) are packaged in
panels, accordion-folded in two directions,
and placed onto pallets. Whether the liner is
shipped in rolls or panels, ensure proper stor-
age. The rolls and panels should be packaged
so that fork lifts or other equipment can safe-
ly transport them. For rolls, this involves
preparing the roll to have a sufficient inside
diameter so that a fork lift with a long rod,
known as a stinger, may be used for lifting
and moving. For accordion panels, proper
packaging involves using a structurally-sound
pallet, wrapping panels in treated cardboard
or plastic wrapping to protect against ultravi-
olet exposure, and using banding straps with
appropriate cushioning. Once the liners have
been transported to the site, the rolls or pan-
els may be stored until the subgrade or sub-
base (either natural soils or another geosyn-
thetic) is prepared.
Subgrade Preparation
Before a geomembrane liner is installed,
prepare the subgrade or subbase. The sub-
grade material should meet specified grading,
moisture content, and density requirements.
In the case of a soil subgrade, ensure that
construction equipment used to place the
liner does not deform the underlying materi-
als. If the underlying materials are geosyn-
thetics, such as geonets or geotextiles, remove
all folds and wrinkles before the liner is
placed. For further information on geomem-
brane placement, see Chapter 3 of EPA's
1993 technical guidance document Quality
Assurance and Quality Control for Waste
Containment Facilities (EPA600-R-93-182).
Testing Prior to Construction
Before any construction begins, test both
the geomembrane materials from the manu-
facturer and the installation procedures.
Acceptance and conformance testing is used
to evaluate the performance of the manufac-
tured geomembranes. Constructing test strips
may help evaluate how well the intended
construction process and quality control pro-
cedures will work.
Acceptance and Conformance Testing.
Perform acceptance and conformance testing
on the geomembrane liner received from the
manufacturer to determine whether the mate-
rials meet the specifications requested. While
the specific ASTM test methods vary depend-
ing on geomembrane type, recommended
acceptance and conformance testing for
geomembranes includes evaluations of thick-
ness, tensile strength and elongation, and
puncture and tear resistance testing, as appro-
priate. For most geomembrane liner types, the
7B-13
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Protecting Ground Water—Designing and Installing Liners
recommended ASTM method for testing
thickness is ASTM D-5199.8 For tensile
strength and elongation, ASTM D-638 is rec-
ommended for the HDPE and LLDPE sheets,
while ASTM D-882 and ASTM D-751 are rec-
I
ommended for PVC and CSPE geomem-
branes, respectively.9 Puncture resistance test-
ing is typically recommended for HDPE and
LLDPE geomembranes using Federal Test
Method (FTM) Standard 101C To evaluate
tear resistance-for HDPE, LLDPE, and PVC
geomembrane liners, the recommended test-
ing method is ASTM D-1004, Die C11 For
CSPE-R geomembranes, ply adhesion is more
of a concern than tear or puncture resistance
and can be evaluated using ASTM D-413,
Machine Method, Type A.12
Test Strips. In preparation for liner place-
ment and field seaming, develop test strips
and trial seams as part of the construction
process. Construction of such samples
should be performed in a manner that repro-
duces all aspects of field production.
Providing an opportunity to test seaming
methods and workmanship helps ensure that
the quality of the seams remains constant
and meets specifications throughout the
entire seaming process,
Temperature Effects
Liner material properties may be altered
by extreme temperatures. High temperatures
may cause geomembrane liner surfaces to
stick together, a process commonly referred
to as blocking. On the other hand, low tem-
perature may cause the liner to crack when
unrolled or unfolded. Recommended maxi-
mum and minimum allowable sheet tempera-
tures for unrolling or unfolding geomem-
brane liners are 50 °C (122 °F) and 0 °C (32
°F), respectively. In addition to sticking and
cracking, extreme temperatures may cause
geomembranes to contract or expand.
Polyethylene geomembranes expand when
heated and contract when cooled. Other
geomembranes may contract slightly when
heated. Those responsible for placing the
liner need to take temperature effects into
account as they place, seam, and backfill in
the field.
Wind Effects
Take measures to protect geomembrane
liners from wind damage. Windy conditions
may increase the potential for tearing as a
result of uplift. If wind uplift is a potential
problem, panels may be weighted down with
sand bags.
Seaming Processes
Once panels or rolls have been placed,
another critical step involves field-seaming
the separate panels or rolls together. The
selected seaming process , such as thermal or
chemical seaming, will depend on the chemi-
cal composition of the liner. To ensure the
integrity of the seam, use: the seaming
method recommended by the manufacturer.
Thermal seaming uses heat to bond together
the geomembrane panels. Examples of ther-
mal seaming processes include extrusion
welding and thermal fusion (or melt bond-
ing). Chemical seaming may involve the use
of solvents, cement, or an adhesive. Chemical
seaming processes include chemical fusion
and adhesive seaming. For more information
on seaming methods, the EPA document,
7B-14
*ASTM D-5199, Standard Test Method for Measuring Nominal Thickness of Geotextiles and Geomembranes.
9 ASTM D-638, Standard Test Method for Tensile Properties of Plastics.
ASTM D-882, Standard Test Methods for Tensile Properties of Thin Plastic Sheeting.
ASTM D-751, Standard Test Methods for Coated Fabrics. :
M FTM Standard 101 C, Puncture Resistance and Elongation Test (1/8 Inch Radius Probe Method).
I
11 ASTM D-1004, Standard Test Method for Initial Tear Resistance of Plastic Film and Sheeting.
" ASTM D-413, Standard Test Methods for Rubber Property-Adhesion to Flexible Substrate.
-------
Protecting Ground Water—Designing and Installing Liners
Technical Guidance Document: Inspection
Techniques for the Fabrication of Geomembrane
Field Seams (EPA530-SW-91-051), contains a
full chapter on each of the traditional seam-
ing methods and additional discussion of
emerging techniques, such as ultrasonic, elec-
trical conduction, and magnetic energy
source methods.
Consistent quality in fabricating field
seams is paramount to liner performance.
Conditions that could affect seaming should
be monitored and controlled during installa-
tion. Factors influencing seam construction
and performance include: ambient tempera-
ture, relative humidity, wind uplift, changes
in geomembrane temperature, subsurface
water content, type of supporting surface
used, skill of the seaming crew, quality and
consistency of chemical or welding materials,
preparation of liner surfaces to be joined,
moisture at the seam interface, and cleanli-
ness of the seam interface.
To help control some of these factors, no
more than the amount of sheeting that can be
used during a shift or a work day should be
deployed at one time. To prevent erosion of
the underlying soil surface or washout of the
geomembrane, proper storm water control
measures should be employed. Ambient tem-
perature may become a concern, if the
geomembrane liner has a high percentage of
carbon black. Although the carbon black will
help to prevent damage resulting from ultra-
violet radiation, because its dark color
absorbs heat, it may increase the ambient
temperature of the geomembrane, making
installation more complicated. To avoid sur-
face moisture or high subsurface water con-
tent, geomembranes should not be deployed
when the subgrade is wet.
Regardless of how well a geomembrane
liner is designed, its ability to meet perfor-
mance standards depends on proper quality
assurance and quality control during installa-
tion. Geomembrane sheets and seams are
subject to tearing and puncture during instal-
lation; punctures or tears can result from con-
tact with jagged edges or underlying materials
or by applying stresses greater than the
geomembrane sheet can handle. Proper quali-
ty assurance and quality control can help
minimize the occurrence of pinhole or seam
leaks. For example, properly preparing the
underlying layer and ensuring that the gravel
is of an acceptable size reduces the potential
for punctures.
Protection and Backfilling
Geomembrane liners that can be damaged
by exposure to weather or work activities
should be covered with a layer of soil or a
geosynthetic as soon as possible after quality
assurance activities associated with geomem-
brane testing are completed. If the backfill
layer is a soil material, it will typically be a
drainage material like sand or gravel. If the
cover layer is a geosynthetic, it will typically
be a geonet or geocomposite drain placed
directly over the geomembrane. Careful
placement of backfill materials is critical to
avoid puncturing or tearing the geomem-
brane material.
For soil covers, three considerations deter-
mine the amount of slack to be placed in the
underlying geomembrane. These considera-
tions include selecting the appropriate type of
soil, using the proper type of equipment, and
establishing a placement procedure for the
soil. When selecting a soil for backfilling,
characteristics to consider include particle
size, hardness, and angularity, as each of these
may affect the potential for tearing or punc-
turing the liner. To prevent wrinkling, soil
covers should be placed over the geomem-
brane in such a way that construction vehicles
do not drive directly on the liner. Care should
be taken not to push heavy loads of soil over
the geomembrane in a continuous manner.
7B-15
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Protecting Ground Water—Designing and Installing Liners
Forward pushing can cause localized wrinkles
to develop and overturn in the direction of
movement. Overturned wrinkles create sharp
creases and localized stress in the liner and
may lead to premature failure. A recommend-
ed method for placing soil involves continual-
ly placing small amounts of soil or drainage
material and working outward over the toe of
the previously placed material.
Another recommended method involves
placing soil over the liner with a large back-
hoe and spreading it with a bulldozer or sim-
ilar equipment. If a predetermined amount of
slack is to be placed in the geomembrane,
the temperature of the liner becomes an
important factor, as it will effect the ability of
the liner to contract and expand. Although
the recommended methods for covering
geomembrane liners with soil may take more
time than backfilling with larger amounts of
soil, these methods are designed to prevent
damage caused by covering the liner with too
much soil too quickly. In the long run, pre-
venting premature liner failure can be faster
and more cost-effective than having to repair
a damaged liner.
The types of geosynthetics that are often
used as protective covering include geotex-
tiles and geonets. Geogrids and drainage geo-
composites may be used for cover soil rein-
forcement on slopes. Consult Appendix VIII
for additional information on geosynthetic
materials. For geosynthetic protective covers,
as with soil backfilling, to prevent tearing or
puncturing, construction vehicles should not
be permitted to move directly on the
geomembrane. Seaming-related equipment
may be allowed on the geomembrane liner,
as long as it does not damage the liner.
Geosynthetic materials are placed directly on
the liner and are not bonded to it.
Testing During Construction
Testing during construction enables assess-
ment of the integrity of the seams connecting
the geomembrane panels. Tests performed on
the geomembrane seams are categorized as
either destructive or nondestructive.
Destructive Testing. Destructive testing
refers to removing a sample from the liner
seam or sheet and performing tests on the
sample. For liner seams, destructive test-
ing includes shear testing and peel testing;
for liner sheets, it involves tensile testing.
While quality control procedures often
require destructive testing prior to con-
struction, in order to ensure that the
installed seams and sheets meet perfor-
mance standards, destructive testing
should be performed during construction
also. For increased quality assurance, peel
and shear tests on samples from the
installed geomembrane should be per-
formed by an independent laboratory.
Testing methods for shear testing, peel
testing, and tensile testing vary for differ-
ent geomembrane liner types.
Determining the number of samples to
take is a difficult step. Taking too few sam-
ples results in a poor statistical representa-
tion of the geomembrane quality. On the
other hand, taking too many samples
requires additional costs and increases the
potential for defects. Defects can result
from the repair patches used to cover the
areas from which samples were taken.
I
A common sampling strategy is "fixed
increment sampling" where samples are
taken at a fixed increment along the length
of the geomembrane. Increments range
from 80 to 230 m (250 to 750 ft), with a
commonly specified value of 150 m (500
ft). The type of welding, such as extrusion
or fusion welding, used to connect the
7B-16
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Protecting Ground Water—Designing and Installing Liners
seams and the type of geomembrane liner
may also help determine the appropriate
sampling interval. For example, extrusion
seams on HDPE require grinding prior to
welding and if extensive grinding occurs,
the strength of the HDPE may decrease. In
such cases, sampling at closer intervals,
such as 90 to 120 m (300 to 400 ft), may
provide a more accurate description of
material properties. If the seam is a dual
hot edge seam, both the inner and outer
seams may need to be sampled and tested.
If test results for the seam or sheet samples
do not meet the acceptance criteria for the
destructive tests, continue testing the area
surrounding the rejected sample to determine
the limits of the low quality seam. Once the
area of low quality has been identified, then
corrective measures, such as seaming a cap
over the length of the seam or reseaming the
affected area, may be necessary.
Nondestructive Testing. Unlike destructive
tests, which examine samples taken from
the geomembrane liner, nondestructive
tests are designed to evaluate the integrity
of larger portions of geomembrane seams
without removing pieces of the geomem-
brane for testing. Common nondestructive
testing methods include: the probe test, air
lance, vacuum box, ultrasonic methods
(pulse echo, shadow, and impedance
planes), electrical spark test, pressurized
dual seam, and electrical resistivity. Select
the test method most appropriate for the
material and seaming method. If sections
of a seam fail to meet the acceptable crite-
ria of the appropriate nondestructive test,
then those sections need to be delineated
and patched, reseamed, or retested. If
repairing such sections results in large
patches or areas of reseaming, then
destructive test methods should be used to
verify the integrity of such pieces.
C. Geosynthetic Clay Liners
If a risk evaluation recommended the use
of a single liner, another option to consider is
a geosynthetic clay liner (GCL). GCLs are fac-
tory-manufactured, hydraulic barriers typical-
ly consisting of bentonite clay (or other very
low permeability materials), supported by
geotextiles and/or geomembranes held
together by needling, stitching, or chemical
adhesives. GCLs can be used to augment or
replace compacted clay liners or geomem-
branes, or they can be used in a composite
manner to augment the more traditional
compacted clay or geomembrane materials.
GCLs are typically used in areas where clay is
not readily available or where conserving air
space is an important factor. As GCLs do not
have the level of long-term field performance
data that geomembranes or compacted clay
liners do, states may require demonstration
that performance of the GCL design will be
comparable to that of compacted clay or
geomembrane liners.
What are the mass per unit area
and hydraulic conductivity rec-
ommendations for geosynthetic
clay liners?
Geosynthetic clay liners are often designed
to perform the same function as compacted
clay and geomembrane liner components. For
geosynthetic clay liners, design for a mini-
mum of 4 kg/m2 (0.8 lb/ft2) dry weight (oven
dried at 105 °C) of bentonite clay with a
hydrated hydraulic conductivity of no more
than 5 x lO'9 cm/sec (2 x 1Q-9 in/sec). Follow
manufacturer specifications for proper GCL
installation.
7B-17
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Protecting Ground Water—Designing and Installing Liners
What issues should be consid-
ered in the design of a geosyn-
thetic clay liner?
Factors to consider in GCL design are the
specific material properties needed for the
liner and the chemical interaction or compat-
ibility of the waste with the GCL. When con-
sidering material properties, keep in mind
that bentonite has a low shear strength when
it is hydrated. Manufacturers have developed
products designed to increase shear strength.
Materials Selection and Properties
For an effective GCL design, material
properties need to be clearly defined in the
specifications used during both manufacture
and construction. Properties that need to be
specified include: type of bonds, thickness,
moisture content, mass per unit area, shear
strength, and tensile strength. Each of these
properties is described below.
Type of bonds. Geosynthetic clay liners
are available with a variety of bonding
designs, which include a combination of
clay, adhesives, and geomembranes or geo-
textiles. The type of adhesives, geotextiles,
and geomembranes used as components of
GCLs varies widely. One type of available
GCL design uses a bentonite clay mixed
with an adhesive bound on each side by
geotextiles. A variation on this design
involves stitching the upper and lower
geotextiles together through the clay layer.
Alternatively, another option is to use a
GCL where geotextiles on each side of
adhesive or nonadhesive bentonite clay are
connected by needle punching. A fourth
variation uses a clay mixed with an adhe-
sive bound to a geomembrane on one
side; the geomembrane can be either the
lower or the upper surface. Figure 3 dis-
plays cross section sketches of the four
variations of GCL bonds. While these
options describe GCLs available at the
time of this guidance, emerging technolo-
gies in GCL designs should also be
reviewed and considered.
Thickness. The thickness of the various
available GCL products ranges from 4 to 6
mm (160 to 320 mil). Thickness measure-
ments are product dependent. Some GCLs
can be quality controlled for thickness
while others cannot. '
Moisture Content. GCLs are delivered to
the job site at moisture contents ranging
from 5 to 23 percent; this may be referred
to as the "dry" state. GCLs are delivered
dry to prevent premature hydration, which
can cause unwanted variations in the
thickness of the clay component as a result
of uneven swelling.
Stability and Shear Strength. GCLs should
be manufactured and .selected to meet the
shear strength requirements specified in
design plans. In this context, shear
strength is the ability of two layers to resist
forces moving them in opposite directions.
Since hydrated bentonite clay has low
shear strength, bentoriite clay may be
placed between geotextiles and stitch
bonded or needle-punched to provide
additional stability. For example, a GCL
with geotextiles supported by stitch bond-
ing has greater internal resistance to shear
in the clay layer than a GCL without any
stitching. Needle-punched GCLs tend to
provide greater resistance than stitch-
bonded GCLs and can also provide
increased friction resistance against an
adjoining layer, because they require the
use of nonwoven geotextiles. Increased
friction is an important consideration on
side slopes.
7B-18
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Protecting Ground Water—Designing and Installing Liners
Figure 3.
Four variations of GCL Bonding Methods
_L
T
Upper Geocottilc
Lower Geotextile
(a) Adhesive Bound day to Upper and Lower Geotextiles
J_
Upper Geoexrile
in Row*
Lower Geomile
Stitch Bonded day Between Upper and Lower Geotextiles
•
* . ^-— — Lower GeoKxtila
(c) Needle Punched day Through Upper and Lower Geotextiles
J_
T
(d) Adhesive Bound Gay tiaaGeomembnne
.Lower or Upper
Source: U.S. EPA. 1993. Technical Guidance Document: Quality Assurance and Quality
Control For Waste Containment Facilities. EPA600-R-93-182.
7B-19
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Protecting Ground Water—Designing and Installing Liners
Interaction With Waste
During the selection process for a GCL
liner, evaluate the chemical compatibility of
the liner materials with the types of waste
that are expected to be placed in the unit.
Certain chemicals, such as calcium, can have
an adverse effect on GCLs, resulting in a loss
of liner integrity. Specific information on
GCL compatibilities should be available from
the manufacturer.
What issues should be consid-
ered in the construction of a
geosynthetic clay liner?
Prior to and during construction, a quali-
fied professional should prepare construction
specifications for the GCL-In these specifica-
tions, procedures for shipping and storing
materials, as well as performing acceptance
testing on delivered materials, should be
identified. The specifications should also
address methods for subgrade preparation,
joining panels, repairing sections, and protec-
tive backfilling.
To reduce the potential for accidental dam-
age or for GCLs to absorb moisture at the site,
try to arrange for "just-in-time-delivery" for
GCLs transported from the factory to the field.
Even with "just-in-time-delivery," it may be
necessary to store GCLs for short periods of
time at the site. Often the rolls can be deliv-
ered in trailers, which can then serve as tem-
porary storage. To help protect the GCLs prior
to deployment, use wooden pallets to keep the
rolls off the ground, placing heavy, waterproof
tarps over the GCL rolls to protect them from
precipitation, and using sandbags to help keep
the tarps in place.
Manufacturer specifications should also
indicate how high rolls of GCLs can be
stacked horizontally during storage. Over-
stacking can cause compression of the core
around which the GCL is wrapped. A dam-
aged core makes deployment more difficult
and can lead to other problems. For example,
rolls are sometimes handled by a fork lift
with a stinger attached. The stinger is a long
tapered rod that fits inside the core. If the
core is crushed, the stinger may damage the
liner during deployment.
Shipment, Handling, and Site Storage
GCLs are manufactured in widths of
approximately 2 to 5 m (7 to 17 ft) and
lengths of 30 to 60 m (100 to 200 ft).
Directly after manufacturing, GCLs are rolled
around a core and covered with a thin plastic
protective covering. This waterproof covering
serves to protect the material from premature
hydration. GCLs should be stored at the fac-
tory with these protective coverings. Typical
storage lengths range from a few days to 6
months. To ensure protection of the plastic
covering and the rolls themselves during
loading and unloading, qualified professionals
should specify the equipment needed at the
site to lift and deploy the rolls properly.
Acceptance and Confarmance Testing
I
Perform acceptance arid conformance test-
ing either upon delivery of the GCL rolls or
at the manufacturer's facility prior to delivery.
Conformance test samples are used to ensure
that the GCL meets the project plans and
specifications. GCLs should be rewrapped
and replaced in dry storage areas immediate-
ly after test samples are removed. Liner speci-
fications should prescribe sampling frequen-
cies based on either total area or on number
of rolls. Conformance testing may include the
following.
7B-20
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Protecting Ground Water—Designing and Installing Liners
Mass Per Unit Area Test The purpose of
evaluating mass per unit area is to ensure
an even distribution of bentonite through-
out the GCL panel. Although mass per
unit area varies from manufacturer to man-
ufacturer, a typical minimum value for
oven dry weight is 4 kg/m2 (0.8 lb/ft2).
Mass per unit area should be tested using
ASTM D-5993.13 This test measures the
mass of bentonite per unit area of GCL.
Sampling frequencies should be deter-
mined using ASTM D-4354.14
Free Swell Test. Free swell refers to the
ability of the clay to absorb liquid. Either
ASTM D-5890 or GRI-GCL1, a test
method developed by the Geosynthetic
Research Institute, can be used to evaluate
the free swell of the material.15
Direct Shear Test. Shear strength of the
GCLs can be evaluated using ASTM D-
5321.16 The sampling frequency for this
performance-oriented test is often based
on area, such as one test per 10,000 m2
(100,000 ft2).
Hydraulic Conductivity Test. Either ASTM
D-5084 (modified) or GRI-GCL2 will mea-
sure the ease with which liquids can move
through the GCL.17
Other Tests. Testing of any geotextiles or
geomembranes should be made on the
original rolls of the geotextiles or geomem-
branes and before they are fabricated into
the GCL product. Once these materials
have been made part of the GCL product,
their properties may change as a result of
any needling, stitching, or gluing.
Additionally, any peel tests performed on
needle punched or stitch bonded GCLs
should use the modified ASTM D-413 with
a recommended sampling frequency of one
test per 2,000 m2 (20,000 ft2).18
Subgrade Preparation
Because the GCL layer is relatively thin,
the first foot of soil underlying the GCL
should have a hydraulic conductivity of 1 x
10'3 cm/sec or less. Proper subgrade prepara-
tion is essential to prevent damage to the
GCL layer as it is installed. This includes
clearing away any roots or large particles that
could potentially puncture the GCL and its
geotextile or geomembrane components. The
soil subgrade should be of the specified grad-
ing, moisture content, and density required
by the installer and approved by a construc-
tion quality assurance engineer for placement
of the GCL. Construction equipment deploy-
ing the rolls should not deform or rut the soil
subgrade excessively. To help ensure this, the
soil subgrade should be smooth rolled with a
smooth-wheel roller and maintained in a
smooth condition prior to deployment.
Joining Panels
GCLs are typically joined by overlapping
panels, without sewing or mechanically con-
necting pieces together. To ensure proper
joints, clearly specify minimum and maxi-
mum overlap distances. Typical overlap dis-
tances range from 150 to 300 mm (6 to 12
in.). For some GCLs, such as needle punched
13 ASTM D-5993, Standard Test Method for Measuring Mass per Unit Area of Geosynthetic Clay Liners.
14 ASTM D-4354, Standard Practice for Sampling of Geosynthetics for Testing.
15 ASTM D-5890, Test Method for Swell Index of Clay Mineral Components of Geosynthetic Clay Liners.
GRI-GCL1, Swell Measurement of the Clay Component of Geosynthetic Clay Liners.
16 ASTM D-5321, Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or
Geosynthetic and Geosynthetic Friction by the Direct Shear Method.
17 ASTM D-5084, Standard Test Method for Measurement of Hydraulic Conductivity of Saturated Porous
Materials Using a Flexible Wall Permeameter. GRI-GCL2, Permeability of Geosynthetic Clay Liners (GCLs).
18 ASTM D-413, Standard Test Methods for Rubber Property-Adhesion to Flexible Substrate.
7B-21
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Protecting Ground Water—Designing and Installing Liners
I
GCLs with nonwoven geotextiles, it may be
necessary to place bentonite on the area of
overlap. If this is necessary, prevent fugitive
bentonite particles from coming into contact
with the leachate collection system, as they
may cause physical clogging.
Repair of Sections Damaged During liner
Placement
During installation, GCLs may incur some
damage to either the clay component or to
any geotextiles or geomembranes. For dam-
age to geotextile or geomembrane compo-
nents, repairs may include patching, using
geotextile or geomembrane materials. If the
clay component is disturbed, a patch made
from the same GCL product should be used
to perform any repairs.
Protective Bocfe/illing
As soon as possible after completion of
quality assurance and quality control activi-
ties, cover GCLs with either a soil layer or a
geosynthetic layer to prevent hydration. The
soil layer may be a compacted clay liner or a
layer of coarse drainage material. The geosyn-
thetic layer is typically a geomembrane; how-
ever, depending on site-specific designs, it
can be a geotextile. As noted earlier, prema-
ture hydration before covering can lead to
uneven swelling, resulting in a GCL with var-
ied thickness. Therefore, a GCL should be
covered with its subsequent soil or geosyn-
thetic layer before a rainfall or snowfall
occurs. Premature hydration is less of a con-
cern for GCLs, where the geosynthetic com-
ponents are needle punched or stitch bond-
ed, because these types of connections can
better limit clay expansion.
i
III. Composite
Liners
A composite liner consists of both a
geomembrane liner and a compacted clay
liner (or a GCL). A composite liner provides
an effective hydraulic barrier by combining
the complementary properties of the two dif-
ferent liners into one system. The geomem-
brane provides a highly impermeable layer to
maximize leachate collection and removal.
The compacted clay liner serves as a backup
in the event of any leakage from the
geomembrane. This discussion refers only to
a compacted clay liner and geomembrane
composite liner. When a GCL is used as part
of a composite liner, it typically replaces the
compacted clay layer of the composite liner.
With a composite liner design, construct a
leachate collection and removal system above
the geomembrane. Information on design
and construction of leachate collection and
removal systems is provided in Section V
below.
What are the thickness and
hydraulic conductivity recommen-
dations for composite liners?
Each component of the composite liner
should follow the recommendations for
geomembranes, geosynthetic clay liners, and
compacted clay liners described earlier.
Geomembrane liners should have a mini-
mum thickness of 30 mil? except for HDPE
liners, which should have a minimum thick-
ness of 60 mil. Similarly, compacted clay lin-
ers should be at least 2 feet thick and are
typically 2 to 5 feet thick. For compacted
clay liners and geosynthetic clay liners, use
materials with maximum hydraulic conduc-
tivities of 1 x 10~7 cm/sec :(4 x 10~8 in/sec) and
5 x 10'9 cm/sec (2 x 10'9 in/sec), respectively.
7B-22
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Protecting Ground Water—Designing and Installing Liners
What issues should be considered
in the design of a composite liner?
As a starting point, follow the design con-
siderations discussed previously for single lin-
ers. In addition, to achieve the benefits of a
combined liner system, install the geomem-
brane to ensure good contact with the com-
pacted clay layer. The uniformity of contact
between the geomembrane and the compact-
ed clay layer helps control the flow of
leachate. Porous material, such as drainage
sand or a geonet, should not be placed
between the geomembrane and the clay layer.
Porous materials will create a layer of higher
hydraulic conductivity, which will increase
the amount of leakage below any geomem-
brane imperfection.
Consider the friction or shear strength
between a compacted clay layer and a
geomembrane. The friction or shear stress at
this surface is often low and may form a weak
plane on which sliding may occur. ASTM D-
5321 provides a test method for determining
the friction coefficient of soil and geomem-
branes.19 When using bentonite-amended soils,
account for how the percentage of bentonite
added and the degree of saturation affect inter-
face friction. To guarantee stable slopes, it is
important to control both the bentonite and
moisture contents. Consider using a textured
geomembrane to increase the friction with the
clay layer and improve stability.
What issues should be consid-
ered in the construction of a
composite liner?
To achieve good composite bonding, the
geomembrane and the compacted clay layer
should have good hydraulic contact. To
improve good contact, smooth-roll the sur-
face of the compacted clay layer using a
smooth, steel-drummed roller and remove
any stones. In addition, place and backfill the
geomembrane so as to minimize wrinkles.
The placement of geomembranes onto a
compacted clay layer poses a challenge,
because workers cannot drive heavy
machines over the clay surface without
potentially damaging the compacted clay
component. Even inappropriate footwear can
leave imprints in the clay layer. To avoid
damaging the clay layer, unroll geomem-
branes by lifting the rolls onto jacks at a cell
side and pulling down on the geomembrane
manually. Also, the entire roll with its core
may be unrolled onto the cell (with auxiliary
support using ropes on embankments).
To minimize desiccation of the compacted
clay layer, place the geomembrane over the
clay layer as soon as possible. Additional
cover materials should also be placed over
the geomembrane. Exposed geomembranes
absorb heat, and high temperatures can dry
out and crack an underlying compacted clay
layer. Daily cyclic changes in temperature can
draw water from the clay layer and cause this
water to condense on the underside of the
geomembrane. This withdrawal of water can
lead to desiccation cracking and potential
interface stability concerns.
IV. Double Liners
(Primary and
Secondary Lined
Systems)
In a double-lined waste management unit,
there are two distinct liners—one primary (top)
liner and one secondary (bottom) liner. Each
liner may consist of compacted clay, a geomem-
brane, or a composite (consisting of a geomem-
brane and a compacted clay layer or GCL).
Above the primary liner, construct a leachate
collection and removal system to collect and
19 ASTM D-5321, Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or
Geosynthetic and Geosynthetic Friction by the Direct Shear Method.
7B-23
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Protecting Ground Water—Designing and Installing Liners
convey liquids out of the waste management
unit and to control the depth of liquids above
the primary liner. In addition, place a leak
detection, collection, and removal system
between the primary and secondary liner.
This leak detection system will provide leak
warning, as well as collect and remove any liq-
uid or leachate that has escaped the primary
liner. See Section V below for information on
I
the design of leachate collection and removal
systems and leak detection, collection, and
removal systems.
What are the thickness and
hydraulic conductivity recom-
mendations for double liners?
Each component of the double liner should
follow the recommendations for geomem-
branes, compacted clay liners, or composite
liners described earlier. Geomembrane liners
should have a minimum thickness of 30 mil,
except for HDPE liners, which should have a
minimum thickness of 60 mil. Similarly, com-
pacted clay liners should be at least 2 feet
thick and are typically 2 to 5 feet thick. For
compacted clay liners and geosynthetic clay
liners, use materials with maximum hydraulic
conductivities of 1 x 10'7 cm/sec (4 x 10'8
in./sec) and 5 x 10'9 cm/sec (2 x 10'9 in/sec),
respectively.
What issues should be consid-
ered in the design and construc-
tion of a double liner?
Like composite liners, double liners are
composed of a combination of single liners.
When planning to design and construct a
double liner, consult the sections on compos-
ite and single liners first. In addition, consult
the sections on leachate collection and
removal systems and leak detection systems.
V. Leachate
Collection and
Leak Detection
Systems
One of the most important functions of a
waste management unit is controlling
leachate and preventing contamination of the
underlying ground water.; Both leachate col-
lection and removal systems and leak detec-
tion systems serve this purpose. Consult with
the state agency too determine if such sys-
tems are required. The primary function of a
leachate collection and removal system is to
collect and convey leachate out of a unit and
to control the depth of leachate above a liner.
The primary function of a leak detection sys-
tem is to detect leachate that has escaped the
primary liner. A leak detection system refers
to drainage material located below the prima-
ry liner and above a secondary liner (if there
is one); it acts as a secondary leachate collec-
tion and removal system. After the leachate
has been removed and collected, a leachate
treatment system may be incorporated to
process the leachate and remove harmful
constituents.
The information in this section on leachate
collection and leak detection systems is
applicable if the unit is a landfill or a waste
pile. Surface impoundments, which manage
liquid wastes, will not have leachate collec-
tion and removal systems unless they will be
closed in-place as landfills; they may have
leak detection systems to; detect liquid wastes
that have escaped the primary liner. No
leachate collection or leak detection systems
are used with land application.
7B-24
-------
Protecting Ground Water—Designing and Installing Liners
Figure 4.
Typical Leachate Collection System
Final grade
Manhole casing
Sweep bend and cap
Solid pipe
Recompacted
clay
rirrirrtLrrrX^^"—as^ir rrr.r^<---Sweep bend
. Perforated pipe
•Pipe backfill
Source: U.S. EPA. 1995. Decision Maker's Guide to Solid Waste Management, Volume II.
EPA530-R-95-023
A. Leachate Collection
System
A typical leachate collection system
includes a drainage layer, collection pipes, a
removal system, and a protective filter layer.
Leachate collection systems are designed to
collect leachate for treatment or alternate dis-
posal and to reduce the buildup of leachate
above the liner system. Figure 4 shows a
cross section of a typical leachate collection
system showing access to pipes for cleaning.
What are the recommendations
for leachate collection and
removal systems?
Design a leachate collection and removal
system to maintain less than 30 cm (12 in.)
depth of leachate, or "head," above the liner if
granular soil is used. If a geosynthetic materi-
al is used, the leachate head should not
exceed the thickness of the geosynthetic
material (this mean the head cannot exceed
0.03 inches). The reason for maintaining this
level is to prevent excessive leachate from
building up above the liner, which could
jeopardize the liner's performance. This
should be the underlying factor guiding the
design, construction, and operation of the
leachate collection and removal system.
7B-25
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Protecting Ground Water—Designing and Installing Liners
Design a leachate collection and removal
system capable of controlling the estimated
volume of leachate. To determine potential
leachate generation, use water balance equa-
tions or models. The most commonly used
method to estimate leachate generation is the
EPA's Hydrogeologic Evaluation of Landfill
Performance (HELP) model.20 This model uses
weather, soil, and waste management unit
design data to determine leachate generation
rates.
What issues should be consid-
ered in the design of a leachate
collection and removal system?
Design a leachate collection and removal
system to include the following elements: a
low-permeability base, a high-permeability
drainage layer, perforated leachate collection
pipes, a protective filter layer, and a leachate
removal system. During design, consider the
stability of the base, the transmissivity of the
drainage layers, and the strength of the col-
lection pipes. Also consider methods to mini-
mize physical, biological, and chemical clog-
ging within the system,
Low-Permeability Base
I
A leachate collection system is placed over
the unit's liner system. The bottom liner
should have a minimum slope of 2 percent to
allow the leachate collection system to gravity
flow to a collection sump. This grade is nec-
essary to provide proper leachate drainage
throughout the operation, closure, and post-
closure of the unit. Estimates of foundation
soil settlement should include this 2 percent
grade as a post-settlement design.
High-Permeability Drainage Layer
A high-permeability drainage layer consists
of drainage materials placed directly over the
low-permeability base, at the same minimum 2
percent grade. The drainage materials can be
either granular soil or geosynthetic materials.
For soil drainage materials, a maximum of 12
inches of materials with a hydraulic conductiv-
ity of at least 1 x 10'2 cm/sec (4 x 10° in./sec) is
recommended. For this reason, sand and grav-
el are the most common soil materials used. If
the drainage layer is going to incorporate sand
or gravel, it should be demonstrated that the
layer will have sufficient bearing capacity to
withstand the waste load of the full unit.
Additionally, if the waste management unit is
designed on grades of 15 percent or higher, it
should be demonstrated that the soil drainage
materials will be stable on the steepest slope in
the design.
Geosynthetic drainage materials such as
geonets may be used in addition to, or in
place of, soil materials. Geonets promote
rapid transmission of liquids and should
always be used in conjunction with a filter
layer or geotextile to prevent clogging.
Geonets consist of integrally connected paral-
lel sets of plastic ribs overlying similar sets at
various angles. Geonets are often used on the
side walls of waste management units because
of their ease of installation. Figure 5 depicts a
typical geonet material configuration.
The most critical factor involved with using
geonets in a high-permeability drainage layer
is the material's ability to transmit fluids under
load. The flow rate of a geonet can be evaluat-
ed by ASTM D-4716.21 Several additional mea-
sures for determining the transmissivity of
geonets are discussed in the EPA document
Solid Waste Disposal Facility Criteria: Technical
Manual (EPA530-R-93-017).
7B-26
20 Available from the U.S. Army Corps of Engineers Web site .
21 ASTM D-4716, Standard Test Method for Constant Head Hydraulic Transmissivity (In-Plane Flow) of
Geotextiles and Geotextile Related Products.
-------
Protecting Ground Water—Designing and Installing Liners
Figure 5.
Typical Geonet Configuration
Channel
Perforated Leadiate Collection Pipes
Whenever the leachate collection system is
a natural soil, a perforated piping system
should be located within it to rapidly transmit
the leachate to a sump and removal system.
Through the piping system, leachate flows
gravitationally to a low point where the sump
and removal system is located. The design of
perforated leachate collection pipes, therefore,
should consider necessary flow rates, pipe siz-
ing, and pipe structural strength. After estimat-
ing the amount of leachate using the HELP
model or a similar water balance model, it is
possible to calculate the appropriate pipe
diameter and spacing. For the leachate collec-
tion system design, select piping material that
can withstand the anticipated weight of the
waste, construction and operating equipment
stresses, and foundation settling. Most leachate
collection pipes used in modern waste man-
agement units are constructed of HDPE. HDPE
pipes provide great structural strength, while
allowing significant chemical resistance to the
many constituents found in leachate. PVC
pipes are also used in waste management
units, but they are not as chemically resistant
as HDPE pipes.
Protective Filter Layer
To protect the
drainage layer and per-
forated leachate collec-
tion piping from clog-
ging, place a filter layer
over the high-permeabil-
ity drainage layer. To
prevent waste material
from moving into the
drainage layer, the filter
layer should consist of a
material with smaller
pore space than the
drainage layer materials
or the perforation openings in the collection
pipes. Sand and geotextiles are the two most
common materials used for filtration. Select
sand that allows adequate flow of liquids, pre-
vents migration of overlying solids or soils into
the drainage layer, and minimizes clogging
during the service life. In designing the sand
filter, consider particle size and hydraulic con-
ductivity. The advantages of using sand materi-
als include common usage, traditional design,
and durability.
Any evaluation of geotextile materials
should address the same concerns but with a
few differences. To begin with, the average
pore size of the geotextile should be large
enough to allow the finer soil particles to pass
but small enough to retain larger soil particles.
The number of openings in the geotextile
should be large enough that, even if some of
the openings clog, the remaining openings will
be sufficient to pass the design flow rate. In
addition to pore size, geotextile filter specifica-
tions should include durability requirements.
The advantages of geotextile materials include
vertical space savings and easy placement.
Chapter 5 of EPA's 1993 technical guidance
document Quality Assurance and Quality
Control for Waste Containment Facilities
(EPA600-R-93-182) offers guidance on protec-
tion of drainage layers.
7B-27
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Protecting Ground Water—Designing and Installing Liners
Lcadiate Removed System
Leachate removal often involves housing a
sump within the leachate collection drainage
layer. A sump is a low point in the liner con-
structed to collect leachate. Modem waste
management unit sumps often consist of pre-
fabricated polyethylene structures supported
on a steel plate above the liner. Especially with
geomembrane liners, the steel plate serves to
support the weight of the sump and protect
the liner from puncture. Reinforced concrete
pipe and concrete flooring may be used in
place of the polyethylene structure but are
considerably heavier.
To remove leachate that has collected in the
sump, use a submersible pump. Ideally, the
sump should be placed at a depth of 1 to 1.5
m (3 to 5 ft) to allow enough leachate collec-
tion to prevent the pump from running dry.
Consider installing a level control, backup
pump, and warning system to ensure proper
sump operation. Also consider using a backup
pump as an alternate to the primary pump
and to assist it during high flow periods. A
warning system should be used to indicate
pump malfunction.
Standpipes, vertical pipes extending
through the waste and cover system, offer one
method of removing leachate from a sump
without puncturing the liner. Alternatively,
remove leachate from a sump using pipes that
are designed to penetrate the liner. When
installing pipe penetrations through the liner,
proceed with extreme caution to prevent any
liner damage that could result in uncontained
leachate. Both of these options rely on gravity
to direct leachate to a leachate collection pond
or to an external pumping station.
Minimizing Clogging
Leachate collection and removal systems are
susceptible to physical, biological, and chemi-
cal clogging. Physical clogging may occur
through the migration of finer-grained materi-
als into coarser-grained materials, thus reduc-
ing the hydraulic conductivity of the coarser-
grained material. Biological clogging may
occur through bacterial growth in the system
due to the organic and nutrient materials in
leachate. Chemical clogging may be caused by
chemical precipitates, such as calcium carbon-
ates, causing blockage or cementation of gran-
ular drainage material.
Proper selection of drainage and filter
materials is essential to minimize clogging in
the high-permeability drainage layer. Soil and
geotextile filters may be used to minimize
physical clogging of both granular drainage
material and leachate collection pipes. When
placed above granular drainage material,
these filters may also double as an operations
layer to prevent sharp waste from damaging
the liner or leachate collection and removal
systems. To minimize chemical and biological
clogging for granular drainage material, the
best procedure is to keep the interstices of
the granular drainage material as open as
possible.
The leachate collection pipes are also sus-
ceptible to similar clogging. To prevent this,
incorporate measures into the design to allow
for routine pipe cleaning, using either
mechanical or hydraulic methods. The clean-
ing components can include pipes with a 15
cm (6-in.) minimum diameter to facilitate
cleaning, access located at major pipe intersec-
tions or bends to allow for inspections and
cleaning, and valves, ports, or other appurte-
nances to introduce biocides and/or cleaning
solutions. Consider incorporating an antimi-
crobial additive into the plastic composition to
delay or reduce biological growth. Also,
ensure that the design does not include wrap-
ping perforated leachate collection pipes
directly with geotextile filters. If the geotextile
becomes clogged, it can block flow into the
pipe.
7B-28
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Protecting Ground Water—Designing and Installing Liners
B. Leak Detection System
The leak detection system (LDS) is also
known as the secondary leachate collection
and removal system. It uses the same drainage
and collection components as the primary
leachate collection and removal system and
identifies any leakage from the primary liner
system. It also serves to collect and remove
any leakage from the primary system. The LDS
should be located directly below the primary
liner and above the secondary liner.
What are the recommendations
for leak detection systems?
The LDS should be designed to assess the
adequacy of the primary liner against leachate
leakage; it should cover both the bottom and
side walls of a waste management unit. The
LDS should be designed to collect leakage
through the primary layer and transport it to a
sump within 24 hours.
The LDS should allow for monitoring and
collection of leachate escaping the primary
liner system. Monitor the LDS on a regular
basis. If the volume of leachate detected by the
LDS appears to be increasing or is significant,
consider a closer examination to determine
possible remediation measures. A good rule of
thumb is that if the LDS indicates a seepage
level greater than 20 gallons per acre per day,
the system may need closer monitoring or
remediation.
C. Leachate Treatment
System
Once the leachate has been removed from
the unit and collected, take measures to char-
acterize the leachate in order to ensure proper
disposal. There are several methods of disposal
for leachate, and the treatment strategy will
vary according to the disposal method chosen.
Leachate disposal options include discharging
to or pumping and hauling to a publicly
owned treatment works or to an on-site treat-
ment system; treating and discharging to the
environment; land application; and natural or
mechanical evaporation.
When discharging to or pumping and haul-
ing leachate to a publicly owned treatment
works, a typical treatment strategy includes
pre-treatment. Pre-treatment could involve
equalization, aeration, sedimentation, Phone:
adjustment, or metals removal.22 If the plan for
leachate disposal does not involve a remote
treatment facility, pre-treatment alone is not
sufficient.
There are two categories of leachate treat-
ment, biological and physical/chemical. The
most common method of biological treatment
is activated sludge. Activated sludge is a "sus-
pended-growth process that uses aerobic
micro-organisms to biodegrade organic conta-
minants in leachate."23 Among physical/chemi-
cal treatment techniques, the carbon absorption
process and reverse osmosis are the two most
common methods. Carbon absorption uses car-
bon to remove dissolved organics from leachate
and is very expensive. Reverse osmosis involves
feeding leachate into a tubular chamber whose
wall acts as a synthetic membrane, allowing
water molecules to pass through but not pollu-
tant molecules, thereby separating clean water
from waste constituents.
What are the recommendations
for leachate treatment systems?
Review all applicable federal and state regu-
lations and discharge standards to determine
which treatment system will ensure long-term
compliance and flexibility for the unit. Site-
specific factors will also play a fundamental
role in determining the proper leachate treat-
ment system. For some facilities, onsite storage
and treatment may not be an option due to
u Arts, Tom. "Alternative Approaches For Leachate Treatment." World Wastes.
7B-29
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Protecting Ground Water—Designing and Installing Liners
space constraints. For other facilities, having a
nearby, publicly owned treatment works may
make pre-treatment and discharge to the treat-
ment works an attractive alternative.
VI, Construction
Quality
Assurance and
Quality Control
Even the best unit design will not translate
into a structure that is protective of human
health and the environment, if the unit is not
properly constructed. Manufacturing quality
assurance and manufacturing quality control
(MQA and MQC) are also important issues
for the overall project; however, they are
discussed only briefly here since they are pri-
marily the responsibility of a manufacturer.
Nonetheless, select a manufacturer who
incorporates appropriate quality assurance
and quality control (QA and QC) mecha-
nisms as part of the manufacturing process.
The remainder of this section provides a gen-
eral description of the components of a con-
struction quality assurance and construction
quality control (CQA and CQC) program for
a project. CQA and CQC are critical factors
for waste management units. They are not
interchangeable, and the distinction between
them should be kept in mind when prepar-
ing plans. CQA is third party verification of
quality, while CQC consists of in-process
measures taken by the contractor or installer
to maintain quality. Establish clear protocols
for identifying and addressing issues of con-
cern throughout every stage of construction.
What is manufacturing quality
assurance?
The desired characteristics of liner materials
should be specified in the 'unit's contract with
the manufacturer. The manufacturer is respon-
sible for certifying that materials delivered
conform to those specifications. MQC imple-
mented to ensure such conformance might
take the form of process quality control or
computer-aided quality control. If requested,
the manufacturer should provide information
on the MQC measures used, allow unit per-
sonnel or engineers to visit the manufacturing
facility, and provide liner samples for testing.
The manufacturer should have a dedicated
individual in charge of MQC who would work
with unit personnel in these areas.
MQC, MQA, CQC, and CQA
Manufacturing quality control (MQC) is
measures taken by the manufacturer to
ensure compliance with the material and
workmanship specifications of the facility
manager.
Manufacturer quality assurance (MQA) is
measures taken by facility personnel, or
by an impartial party brought in expressly
for the purpose, to determine if the man-
ufacturer is in compliance with the speci-
fications of the facility manager.
Construction quality control (CQQ is
measures taken by the installer or con-
tractor to ensure compliance with the
installation specifications of the facility
manager.
Construction quality assurance (CQA) is
measures-taken by facility personnel, or by
an impartial party brought in expressly for
the purpose, to determine if the installer
or contractor is in compliance with the
installation specifications of the facility
manager.
Ibid.
78-30
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Protecting Ground Water—Designing and Installing Liners
What is construction quality
assurance?
CQA is a verification tool employed by the
facility manager or regulatory agency, consist-
ing of a planned series of observations and
tests designed to ensure that the final product
meets project specifications. CQA testing,
often referred to as acceptance inspection, pro-
vides a measure of the final product quality
and its conformance with project plans and
specifications. Performing acceptance inspec-
tions routinely, as portions of the project
become complete, allows early detection and
correction of deficiencies, before they become
large and costly.
On routine construction projects, CQA is
normally the concern of the facility manager
and is usually performed by an independent,
third-party testing firm. The independence of
the testing firm is important, particularly when
a facility manager has the capacity to perform
the CQA activities. Although the facility's in-
house CQA personnel may be registered pro-
fessional engineers, a perception of misrepre-
sentation may arise if CQA is not performed
by an independent third party.
The independent party should designate a
CQA officer and fully disclose any activities or
relationships that the officer has with the facili-
ty manager that may impact his or her impar-
tiality or objectivity. If such activities or rela-
tionships exist, the CQA officer should
describe actions that have been or can be
taken to avoid, mitigate, or neutralize the pos-
sibility they might affect the CQA officer's
objectivity. State regulatory representatives can
help evaluate whether these mechanisms are
sufficient to ensure acceptable CQA.
What is construction quality
control?
CQC is an ongoing process of measuring
and controlling the characteristics of the prod-
uct in order to meet manufacturer's or project
specifications. CQC inspections are typically
performed by the contractor to provide an in-
process measure of construction quality and
conformance with the project plans and speci-
fications, thereby allowing the contractor to
correct the construction process if the quality
of the product is not meeting the specifications
and plans. Since CQC is a production tool
employed by the manufacturer of materials
and by the contractor installing the materials
at the site, this guidance does not cover CQC
in detail. CQC is performed independently of
CQA. For example, while a geomembrane
liner installer will perform CQC testing of field
seams, the CQA program will require indepen-
dent testing of those same seams by a third-
party inspector.
How can implementation of
CQA and CQC plans be
ensured?
When preparing to design and construct a
waste management unit, regardless of liner
type, develop CQA and CQC plans cus-
tomized to the project. To help the project run
smoothly, the CQA plan should be easy to fol-
low. Organize the CQA plan to reflect the
sequence of construction and write it in lan-
guage that will be familiar to an average field
technician. For a more detailed discussion of
specific CQA and CQC activities recommend-
ed for each type of waste management unit,
consult the EPA document Technical Guidance
Document: Quality Assurance and Quality
Control for Waste Management Containment
Facilities (EPA600-R-93-182). This document
provides information needed to develop
7B-31
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Protecting Ground Water—Designing and Installing Liners
comprehensive QA plans and to carry out QC
procedures at waste management units.
CQA and CQC plans can be implemented
through a series of meetings and inspections,
which should be documented thoroughly.
Communication among all parties involved in
design and construction of a waste manage-
ment unit is essential to ensuring a quality
product. Define responsibility and authority in
written QA and QC plans and ensure that
each party involved understands its role. Pre-
construction meetings are one way to help
clarify roles and responsibilities. During con-
struction, meetings may continue to be useful
to help resolve misunderstandings and to
identify solutions to unanticipated problems
that may develop. Some examples of typical
meetings during the course of any construc-
tion project include pre-bid meetings, resolu-
tion meetings, pre-construction meetings, and
progress meetings.
A. Compacted Clay Liner
Quality Assurance and
Quality Control
Although manufacturing quality control.
and quality assurance are often the responsi-
bility of the materials manufacturer, in the
case of soil components, manufacturing and
construction quality control testing can be the
responsibility of the facility manager. In the
CQA and CQC plans, specify procedures for
quality assurance and quality control during
construction of the compacted clay liners.
How can implementation of QA
and QC be ensured for a com-
pacted clay liner?
QC testing is typically performed by the
contractor on materials used in construction of
the-liner. This testing examines material prop-
i
erties such as moisture content, soil density,
Atterberg limits, grain size,, and laboratory
hydraulic conductivity. Additional testing of
soil moisture content, density, lift thickness,
and hydraulic conductivity ensures that the
waste management unit has been constructed
in accordance with the plans and technical
specifications. ;
CQA testing for soil liners includes the
same tests described for QC testing in the
paragraph above. Generally, the tests are per-
formed less frequently. CQA testing is per-
formed by an individual or an entity indepen-
dent of the contractor. Activities of the CQA
officer are essential to document quality of
construction. The responsibilities of the CQA
officer and his or her staff may include com-
municating with the contractor; interpreting
and clarifying project drawings and specifica-
tions with the designer, facility manager, and
contractor; recommending acceptance or
rejection by the facility manager of work com-
pleted by the construction contractor; and
submitting blind samples, such as duplicates
and blanks, for analysis by the contractor's
testing staff or independent laboratories.
Also consider constructing a test pad prior
to full-scale construction as a CQA tool. As
described earlier in the section on compacted
clay liners, pilot construction or test fill of a
small-scale test pad can be used to verify that
the soil, equipment, and construction proce-
dures can produce a liner that performs
according to the construction drawings and
specifications.
Specific factors to examine or test during
construction of a test fill include: preparation
and compaction of foundation material to the
required bearing strength; methods of con-
trolling uniformity of the soil material; com-
pactive effort, such as type of equipment and
number of passes needed to achieve required
soil density and hydraulic conductivity; and
lift thickness and placement procedures
7B-32
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Protecting Ground Water—Designing and Installing Liners
needed to achieve uniformity of density
throughout a lift and prevent boundary
effects between lifts or between placements in
the same lift. Test pads can also provide a
means to evaluate the ability of different types
of soil to meet hydraulic conductivity
•'•equirements in the field. In addition to
allowing an opportunity to evaluate material
performance, test pads also allow evaluation
of the skill and competence of the construc-
tion team, including equipment operators
and QC specialists.
B. Geomembrane Liner
Quality Assurance and
Quality Control
As with the construction of soil liners,
installation of geomembrane liners should be
in conformance with a CQA and CQC plan.
The responsibilities of the CQA personnel for
the installation of the geomembrane are gener-
ally the same as the responsibilities for the
construction of a compacted clay liner, with
the addition of certain activities including
observations of the liner storage area and liners
in storage, and handling of the liner as the
panels are positioned in the cell. Geomem-
brane CQA staff should also observe seam
preparation, seam overlap, and materials
underlying the liner.
How can implementation of QA
and QC be ensured for a
geomembrane liner?
Prior to installation, work with the
geomembrane manufacturer to ensure the
labeling system for the geomembrane rolls is
clear and logical, allowing easy tracking of the
placement of the rolls within the unit. In addi-
tion, examine the subgrade surface with both
the subgrade contractor and the liner installer
to ensure it conforms to specifications.
Once liner installation is underway, CQA
staff may be responsible for observations of
destructive testing conducted on scrap test
welds prior to seaming. Geomembrane CQA
staff may also be responsible for sending
destructive seam sampling to an independent
testing laboratory and reviewing the results for
conformance to specifications. Other observa-
tions for which the CQA staff are typically
responsible include observations of all seams
and panels for defects due to manufacturing
and/or handling and placement and observa-
tions of all pipe penetrations through a liner.
Test methods, test parameters, and testing
frequencies should be specified in the CQA
plan to provide context for any data collect-
ed. Allow for testing frequency to change,
based on the performance of the geomem-
brane installer. If test results indicate poor
workmanship, increase testing. If test results
indicate high quality installation work, con-
sider reducing testing frequencies. When
varying testing frequency, establish well-
defined procedures for modifying testing fre-
quency. In evaluating testing methods, under-
stand the differences among testing methods
and request those methods appropriate for
the material and seaming method used. Use
nondestructive testing methods when possi-
ble to help reduce the number of holes cut
into the geomembrane.
Geomembrane CQA staff also need to docu-
ment the results of their observations and pre-
pare reports indicating the types of sampling
conducted and sampling results, locations of
destructive samples, locations of patches, loca-
tions of seams constructed, and any problems
encountered. In some cases, they may need to
prepare drawings of the liner installation.
Record drawing preparation is frequently
assigned to the contractor, to a representative
of the facility manager, or to the engineer.
Request complete reports from any CQA staff
7B-33
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Protecting Ground Water—Designing and Installing Liners
and the installers. To ensure complete CQA
documentation, maintain daily CQA reports
and prepare weekly summaries.
C. Geosynthetic Clay Liner
Quality Assurance and
Quality Control
Construction quality assurance for geosyn-
thetic clay liners is still a developing area; the
GCL industry is continuing to establish stan-
dardized quality assurance and quality control
procedures. The CQA recommendation for
GCLs can serve as a starting point. Check with
the GCL manufacturer and installer for more
specific information.
How can implementation of QA
and QC be ensured for a
geosynthetic clay liner?
Develop a detailed CQA plan, including
product specifications; shipping, handling,
and storage procedures; seaming methods;
and placement of overlying material. Work
with the manufacturer to verify that the prod-
uct meets specifications. Upon receipt of the
GCL product, verify that it has arrived in good
condition.
During construction, CQA staff will want to
ensure that seams are overlapped properly and
conform to specifications. CQA staff should
also check that panels, not deployed within a
short period of time, are stored properly. In
addition, as overlying material is placed on the
GCL, it is important to restrict vehicle traffic
directly on the GCL. Prohibit direct vehicle
traffic, with the exception of small, 4-wheel,
all terrain vehicles. Even with the small all-ter-
rain vehicles, drivers should take extreme care
to avoid movements, such as sudden starts,
stops, and turns, which may damage the GCL.
As part of the CQA documentation, main-
tain records of weather conditions, subgrade
conditions, and GCL panel locations. Also
document any repairs that were necessary or
other problems identified and addressed.
D. Leachate Collection
System Quality
Assurance and Quality
Control
Leachate collection system CQC should be
performed by the contractor. Similar activi-
ties should be performed for CQA by an
independent party acting on behalf of the
facility manager. The purpose of leachate col-
lection system CQA is to document that the
system is constructed in accordance with
design specifications.
How can implementation of QA
and QC be ensured for a
leachate collection system?
Prior to construction, CQA staff should
inspect all materials to confirm that they meet
the construction plans and specifications.
These materials include: geonets; geotextiles;
pipes; granular material; mechanical, electrical,
and monitoring equipment; concrete forms
and reinforcements; and prefabricated struc-
tures such as sumps and manholes. The
leachate collection system foundation, either a
geomembrane or compacted clay liner, should
also be inspected, upon its completion, to
ensure that it has proper grading and is free of
debris and liquids.
During construction, CQA staff should
observe and document, as appropriate, the
placement and installation of pipes, filter lay-
ers, drainage layers, geonets and geotextiles,
sumps, and mechanical and electrical equip-
ment. For pipes, observations may include
descriptions of pipe bedding material, quality
78-34
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Protecting Ground Water—Designing and Installing Liners
and thickness, as well as the total area covered
by the bedding material. Observations of pipe
installations should focus on the location, con-
figuration, and grading of the pipes, as well as
the quality of connections at joints.
For granular filter layers, CQA activities
may include observing and documenting
material thickness and quality during place-
ment. For granular drainage layers, CQA may
focus on the protection of underlying liners,
material thickness, proper overlap with filter
fabrics and geonets (if applicable), and docu-
mentation of any weather conditions that may
affect the overall performance of the drainage
layer. For geonets and other geosynthetics,
CQA observations should focus on the area of
coverage and layout pattern, as well as the
overlap between panels. For geonets, CQA
staff may want to make sure that the materials
do not become clogged by granular material
that may be carried over, as a result of either
wind or run-off during construction.
Upon completion of construction, each
component should be inspected to identify
any damage that may have occurred during its
installation or during construction of another
component. For example, a leachate collection
pipe may be crushed during placement of a
granular drainage layer. Any damage that does
occur should be repaired, and the repairs
should be documented in the CQA records.
7B-35
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Protecting Ground Water—Designing and Installing Liners
D
D
a
a
Action Items for Lined Units (Landfills, Waste Piles, —
and Surface Impoundments)
Review the recommended location considerations and operating practices for the unit.
Select appropriate liner type—single, composite, or double liner—or in-situ soils, based on
risk characterization.
Evaluate liner material properties and select appropriate clay, geosynthetic, or combination
of materials; consider interactions of liner and soil material with waste.
Develop a construction quality assurance (CQA) plan defining staff roles-and responsibili-
ties and specifying test methods, storage procedures, and construction protocols.
Ensure a stable in-situ soil foundation, for nonengineered liners.
Prepare and inspect subgrade, for engineered liners.
Work with manufacturer to ensure protective shipping, handling and storage of all materials.
Construct a test pad for compacted clay liners.
Test compacted clay liner material before and during construction.
Preprocess clay material to ensure proper water content, remove oversized particles,
and add soil amendments, as applicable.
Use proper lift thickness and number of equipment passes to achieve adequate compaction.
Protect clay material from drying and cracking.
Develop test strips and trial seams to evaluate geomembrane seaming method.
Verify integrity of factory and field seams for geomembrane materials before and during
construction.
Backfill with soil or geosynthetics to protect geomembranes and geosynthetic clay liners
during construction.
Place backfill materials carefully to avoid damaging the underlying materials.
Install geosynthetic clay liner with proper overlap.
Patch any damage that occurs during geomembrane or geosynthetic clay liner installation.
Design leachate collection and removal system to allow adequate flow and to minimize
clogging; include leachate treatment and leak detection systems, as appropriate.
Document all CQA activities, including meetings, inspections, and repairs.
D
D
a
a
D
a
a
a
a
a
D
a
a
a
a
a
7B-36
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Protecting Ground Water—Designing and Installing Liners
Resources
ASTM D-413. 1993. Standard test methods for rubber property-adhesion to flexible substrate.
ASTM D-422. 1990. Standard test method for particle-size analysis of soils.
ASTM D-638. 1991. Standard test method for tensile properties of plastics.
ASTM D-698. 1991. Test method for laboratory compaction characteristics of soil using standard
effort (12,400 ft-lbf/ft3 (600 kN-m/m3)).
ASTM D-751. 1989. Standard test methods for coated fabrics.
ASTM D-882. 1991. Standard test methods for tensile properties of thin plastic sheeting.
ASTM D-1004. 1990. Standard test method for initial tear resistance of plastic film and sheeting.
ASTM D-1557. 1991. Test method for laboratory compaction characteristics of soil using modified
effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)).
ASTM D-4318. 1993. Standard test method for liquid limit, plastic limit, and plasticity index of soils.
ASTM D-4354. 1989. Standard practice for sampling of geosynthetics for testing.
ASTM D-4716. 1987. Standard test method for constant head hydraulic transmissivity (in-plane flow)
of geotextiles and geotextile related products.
ASTM D-5084. 1990. Standard test method for measurement of hydraulic conductivity of saturated
porous materials using a flexible wall permeameter.
ASTM D-5199. 1991. Standard test method for measuring nominal thickness of geotextiles and
geomembranes.
ASTM D-5261. 1992. Standard test method for measuring mass per unit area of geotextiles.
ASTM D-5321. 1992. Standard test method for determining the coefficient of soil and geosynthetic or
geosynthetic and geosynthetic friction by the direct shear method.
78-37
-------
Protecting Ground Water—Designing and Instating Liners
Resources (cont.)
Bagchi, A. 1994. Design, construction, and monitoring of landfills.
Berg, R., and L. Well. 1996. A position paper on: The use of geosynthetic barriers in nonhaz-
ardous industrial waste containment.
Berger, E. K. and R. Berger. 1997. The .global water cycle.
Borrelli, J. and D. Brosz. 1986.; Effects of soil salinity on crop yields.
Boulding, J.R. 1995. Practical handbook of soil, vadose zone, and ground water contamination:
Assessment, prevention and remediation. Lewis Publishers.
Brandt, R.C. and K.S. Martin. 1996. The food processing residual management manual.
September.
Daniel, D.E., and R.M. Koerner. 1991. Landfill liners from top to bottom. Civil Engineering.
December.
Daniel, D.E., and R.M. Koerner. 1993. Technical guidance document: Quality assurance and
quality control for waste containment facilities. Prepared for U.S. EPA. EPA600-R-93-182.
Daniel, D.E., and R.M. Koerner. 1995. Waste containment facilities: Guidance for construction,
quality assurance and quality control of liner and cover systems.
Evanylo, G.K. and W. L. Daniels. 1996. The value and suitability of papermill sludge and
sludge compost as a soil amendment-and soilless media substitute. Final report. The Virginia
Department of Agriculture and Consumer Services, P.O. Box 1163, Room 402, Richmond, VA.
April.
Federal Test Method Standard 101C. 1980. Puncture resistance and elongation test (1/8 inch
radius probe method).
Fipps, G. 1995. Managing irrigation water salinity in the lower Rio Grande Valley.
78-38
-------
Protecting Ground Water—Designing and Installing Liners
Resources (cont.)
Geosynthetic Research Institute. 1993. GRI-GCL1, Swell measurement of the clay component of
GCLs.
Geosynthetic Research Institute. 1993. GRI-GCL2, Permeability of geosynthetic clay liners (GCLs).
Idaho Department of Health and Welfare. 1988. Guidelines for land application of municipal and
industrial wastewater. March.
Koerner, R.M. 1994. Designing with geosynthetics, Third edition.
McGrath, L., and E Creamer. 1995. Geosynthetic clay liner applications in waste disposal facilities.
McGrath, L., and P. Creamer. 1995. Geosynthetic clay liner applications. Waste age. May.
Michigan Department of Natural Resources, Waste Characterization Unit. 1991. Guidance for land
application of wastewater sludge in Michigan. March.
Michigan Department of Natural Resources, Waste Characterization Unit. 1991. Guide to prepar-
ing a residuals management plan. March.
Minnesota Pollution Control Agency. 1993. Land treatment of landfill leachate. February.
Northeast Regional Agricultural Engineering Cooperative Extension. 1996. Nutrient management
software: proceedings from the nutrient management software workshop. NRAES-100. December.
Northeast Regional Agricultural Engineering Cooperative Extension. 1996. Animal agriculture and
the environment: Nutrients, pathogens, and community relations. NRAES-96. December.
Northeast Regional Agricultural Engineering Cooperative Extension. 1993. Utilization of food pro-
cessing residuals. Selected papers representing university, industry, and regulatory applications.
NRAES-69. March.
North Carolina Cooperative Extension Service. 1994. Soil facts: Careful soil sampling - the key to
reliable soil test information. AG-439-30.
Oklahoma Department of Environmental Quality. Title 252. Oklahoma administrative code, chap-
ter 647. Sludge and land application of wastewater.
7B-39
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Protecting Ground Water—Designing and Installing Liners
Resources (cont.)
Sharma, H., and S. Lewis. 1994. Waste containment systems, waste stabilization, and landfills: Design
and evaluation.
Smith, M.E., S. Purdy, and M. Hlinko. 1996. Some do's and don'ts of construction quality assurance.
Geotechnical fabrics report. January/February.
!
Spellman, E R. 1997. Wastewater biosolids to compost.
Texas Water Commission. 1983. Industrial solid waste management technical guideline no. 5: Land
application. December.
Tsinger, L. 1996. Chemical compatibility testing: The state of practice. Geotechnical fabrics report.
October/November.
University of Nebraska Cooperative Extension Institute of Agriculture and Natural Resources. 1991.
Guidelines for soil sampling. G91-1000-A. February.
U.S. EPA. 1996. Issue paper on geosynthetic clay liners (GCLs).
U.S. EPA. 1996. Report of 1995 Workshop on Geosynthetic Clay Liners. EPA600-R-96-149. June.
U.S. EPA. 1995. A guide to the biosolids risk assessments for the EPA Part 503 Rule. EPA832-B-93-
005. September.
U.S. EPA. 1995. Decision maker's guide to solid waste management. Volume II. EPA530-R-95-023.
U.S. EPA. 1995. Laboratory methods for soil and foliar analysis in long-term environmental monitoring
programs. EPA600-R-95-077.
U.S. EPA. 1995. Process design manual: Land application of sewage sludge and domestic septage.
EPA625-R-95-001. September.
U.S. EPA. 1995. Process design manual: Surface disposal of sewage sludge and domestic septage.
EPA625-R-95-002. September.
U.S. EPA. 1994. A plain English guide to the EPA Part 503 biosolids rule. EPA832-R-93-003.
September.
U.S. EPA. 1994. Biosolids recycling: Beneficial technology for a better environment. EPA832-R-94-
009. June.
7B-40
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Part IV
Protecting Ground Water
Chapter 7: Section C
Designing A Land Application Program
-------
Contents
i.
Risk Assessment 7C~2
II. Determining a Suitable Waste Application Rate for Land Application 7C-4
A. Waste Parameters 7C'4
B. Total Solids Content 7C'4
C.pH - 7C-6
D. Biodegradable Organic Matter • 7C'6
E. Nutrients 7C~7
E Metals 7C"8
G. Carbon to Nitrogen Ratio - 7C'8
H. Soluble Salts 7C-9
I. Calcium Carbonate Equivalent : 7C-11
J. Pathogens > 7C-11
HI. Soil Properties 7C-12
IV Plant and Microbial Effects , : 7C-1.4
A. Greenhouse and Field Studies 7C-14
B. Effects of Plants and Microbes on Waste Assimilation 7C-16
C. Effects of Waste on Plant and Microbe Growth 7C-17
D. Grazing and Harvesting Restrictions 7C-17
V. Climate - 7C-18
VI. Agronomic Rate T 7C-18
VII. Monitoring • 7C'19
Action Items for Designing a Land Application Program 7C-21
7(~ T)
Resources ;• i^-^
Tables:
Table 1: Summary of Important Waste Parameters • 7C-5
Table 2: Salinity Tolerance of Selected Crops ' 7C-10
Table 3: EC and SAR Levels Indicative of Saline, Sodic, and Saline-Sodic Soils 7C-11
-------
Contents (cont.)
Figures:
Figure 1: A Framework for Evaluating Land Application.
.7C-3
-------
-------
Protecting Ground Water—Designing A Land Application Program
Designing A Land Application Program
Follow the evaluation framework recommended in this section
when applying waste directly to the land for combination of soil
amendment, treatment, and disposal. Account for the designat-
ed ground-water constituents identified in the assessing risk
section, as well as other waste parameters and factors such as
soil properties and plant and microbial interactions.
Land application offers some dis-
tinct benefits. At the same time,
because land application does not
rely on liners to contain waste,
there are some associated risks.
With proper planning and design, a land
application program can meet waste manage-
ment and land preservation goals and avoid
negative impacts such as anaerobic conditions,
noxious odors, long-term damage to soil, and
releases to ground water, surface water, or the
air. This section recommends an evaluation
framework to account for a variety of waste
parameters in addition to the constituents out-
lined in the assessing risk section1, and other
factors such as soil properties and plant and
microbial nutrient use2. A successful land
application program takes the interaction
among all these factors into account.
If agricultural benefit is the primary pur-
pose of land application — to attenuate waste
and maximize plant growth while minimizing
environmental and health risks — the consid-
erations are numerous. If this involves short-
term application on a field, for example a year
or two under a contractual relationship with a
farmer, the evaluation may be completed
more quickly, but it is still important to take
these factors into account. If the primary pur-
pose is waste treatment or disposal, the goal
of maximizing plant growth is probably less
important. However, ensure that the waste
application will not result in environmental
releases and have detrimental effects on future
uses and revegetation of the site.
Examples of land application benefits
include the following:
• Biodegradation of Waste. If a waste stream
contains sufficient organic material, plants
and microorganisms can significantly
biodegrade the waste, assimilating its
organic components into the soil. After
allowing sufficient time for assimilation of
the waste, more waste may be applied to a
given site without significantly increasing
the total volume of waste at the site. This
'The constituents incorporated in the EPAIWEM to assess risk, such as heavy metals and synthetic organ-
ic chemicals, typically have little or no agricultural value and can threaten human health and the environ-
ment even in small quantities. The term "waste parameters" refers to waste constituents, such as nitro-
gen, biodegradable organic matter content, and pH, that have considerable agricultural significance and
that typically threaten human health and the environment only in larger quantities or at extreme levels.
HO CFR Part 503 specifies requirements for land application of sludge from municipal sewage treatment
plants. The Part 503 regulations apply to sewage sludge (now generally referred to as "biosolids") or
mixtures of sewage sludge and industrial process wastes, not to industrial wastes alone. Some of the
specifications in Part 503, for example concerning pathogens, may be helpful in evaluating land applica-
tion for industrial wastes. For mixtures of sewage sludge and industrial waste, the ground-water and air
risk assessments and the evaluation framework laid out in this guidance can help address constituents
that are not covered under the Part 503 regulations.
7C-1
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Protecting Ground Water—Designing A Land Application Program
is in contrast to landfills and waste piles,
in which waste accumulates continually
and does not biodegrade quickly enough
to reduce its volume significantly.
• Inclusion of Liquids. Land application
units can accept bulk, non-containerized
liquid waste. The water content of liquid
wastes may make them desirable at land .
application sites in arid climates. When
managing liquid waste, land application
may reduce the need for expensive
dewatering processes.
• Improvement of SoiL Applied waste can
improve soil quality if the waste contains
appropriate levels of biodegradable organic
matter and nutrients. Nutrients can
improve the chemical composition of the
soils to better support vegetation, while
biodegradable organic matter can improve
soil physical properties to increase water
retention capacity. These chemical and
physical soil improvement aspects of land
application have led to its use in condi-
tioning soil for agricultural use.
Figure 1 outlines a framework for evaluat-
ing land application that incorporates both the
ground-water risk assessment recommended
in this chapter, as well as the other waste
parameters and factors important to land
application. Be sure to address the waste para-
meters and other characteristics discussed in
this evaluation framework when characterizing
wastes for land application.
I. Risk Assessment
If waste leachate contains any of the 191
constituents covered in the Tier I and II
ground-water models, follow the evaluation
recommended in subsections II through IV.
If the waste leachate does contain some of
these constituents, there are some initial steps
to follow:
1) Consider whether any of these con-
stituents are already addressed in any per-
mit, memorandum of .understanding, or
other agreement with a federal, state, or
other regulatory agency concerning land
application. The guidance is not meant to
supersede conditions established in these
regulatory mechanisms.3
Some wastes may be designated by state or
local regulators as essentially equivalent to a
manufactured product or raw material. Such
designations usually are granted only when
use of the designated waste would not pre-
sent a greater environmental and health risk
than would use of the manufactured or raw
material it replaces. Equivalence designations
are included in the category of "other agree-
ments" above. If there are no designated
ground-water constituents other than those
on which the designation is based, follow the
guidelines offered in subsections II through
IV to determine an application rate. If there
are ground-water constituents other than
those on which the designation is based, pro-
ceed with a risk analysis, such as that
described in the section on assessing risk, for
those constituents.
2) Evaluate ground-water and air risks using
the modeling tools in this guidance or other
site-specific models. The ground-water
model recommends whether a waste is
appropriate for land application. In some
cases, pollution prevention or treatment may
lower constituents levels so that a waste can
be land applied. In other cases, land applica-
tion may not be feasible. In this event, pur-
sue other waste management options.
3) Consider direct exposure and ecosystem
pathways. They are more important in land
application, since only in land application is
waste placed in and attenuated by the natural
environment rather than contained by an
7C-2
3EPA has signed agreements with states, industries, and individual sites concerning land application. One
example is EPAs Memorandum of Understanding (MOU) between the American Forest and Paper
Association (AFPA) and the U.S. EPA regarding the implementation of the land application agreements
among AF&PA member Pulp and Paper Mills and the U.S. EPA, January 1994
-------
Protecting Ground Water—Designing A Land Application Program
Figure 1. A Framework for Evaluating Land Application
Perform waste characterization
• Ground-water constituents
• Other waste parameters
Evaluate waste
parameters
Measure soil
properties
Study interaction of
plants and microbes
with waste
Consider ecosystem
impacts and bioaccu-
mulation of waste
Account for climate
Determine theoretical
agronomic application
rate
Determine which
constituents are
covered by permits
MOUs, or other
agreements
For constituents
covered by
agreements, follow
terms of agreements
For constituents not
covered by
agreements, follow
risk assessment
procedure
Evaluate appropriate application rate and
constituent concentrations
Consider pollution prevention,
recycling, or treatment
Reassess periodically and after
process changes
7C-3
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Protecting Ground Water—Designing A Land Application Program
engineered structure. Although a qualitative
tool to evaluate these pathways is not pro-
vided, take them into consideration when
evaluating risks from a land application
unit. During die unit's active life, direct
human exposure to waste or waste-amended
soil is primarily a risk to personnel involved
in die operation. Follow OSHA standards
and ensure that personnel use proper pro-
tective clothing and equipment when work-
ing onsite. Limit direct exposure to others
through steps such as access control and
vehicle washing to prevent tracking waste
and waste amended soil off-site. Access con-
trol will limit exposure of some animals. If
crops will be used for animal fodder or graz-
ing, test harvested fodder for die designated
ground-water constituents before use and
restrict grazing times. After a site is closed,
there may be long-term access risks to
future land uses and the general public. To
minimize these risks long-term access con-
trols or deed restrictions may be appropri-
ate. Consult the chapter on performing clo-
sure and post-closure care for further infor-
mation.
Direct exposure of native animals is often
impossible to control and may be an entry
point for the ground-water constituents
into the ecosystem. Worms, for example,
may be present in the soil and take in
these constituents. Birds or other animals
could then consume the worms, and in
doing so, not only bioaccumulate, but also
transport them off-site. Furthermore, ani-
mals may ingest plants grown on waste-
amended soil. Consider pathways such as
diese in evaluating risk.
II. Determining a
Suitable Waste
Application Rate
for Land
Application
The factors on the left side of Figure 1
provide the basics for determining a prelimi-
nary waste application rate. These factors are
discussed below.
A. Waste Parameters
For land application, in addition to the
designated ground-water constituents, impor-
tant parameters to measure in the waste
include total solids content, pH, biodegrad-
able matter, pathogens, nutrients, metals, car-
bon to nitrogen ratio, soluble salts, and calci-
um carbonate equivalent. These parameters
are summarized in Table 1 and discussed in
the subsequent subsections. In addition to an
initial analysis of these parameters, sample
and characterize the waste on a regular basis
and after process changes that may affect
waste characteristics. This will help deter-
mine whether it is necessary to change land
application practices or consider other waste
management options.
B. Total Solids Content
Total solids content indicates the ratio of
solids to water in a waste. It includes both
suspended and dissolved solids, and is usual-
ly expressed as a percentage of the waste.
Total solids content depends on the type of
waste, as well as whether the waste has been
treated prior to land application. If waste is
dried, composted, dewatered, thickened, or
conditioned prior to land application, water
content is decreased, thereby increasing the
704
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Protecting Ground Water—Designing A Land Application Program
Table 1
Summary of Important Waste Parameters
Waste parameter Significance
Total solids content
PH
Biodegradable organic matter
Nutrients (nitrogen,
phosphorous, and potassium)
Carbon to nitrogn ratio
Soluble salts
Calcium carbonate equivalent
Pathogens
Ground-water constituents
designated in the risk
assessment section including
metals and organic chemicals
Indicates ratio of solids to water in waste and influences
application method.
Controls metals solubility (and therefore mobility of metals toward
ground water) and affects biological processes.
Influences soil's water holding capacity, cation exchange, and other
soil physical and chemical properties, and odor.
Affect plant growth; nitrogen is a major determinant of application
rate; can migrate to and contaminate ground water or cause
phytotoxicity if applied in excess.
Influences availability of nitrogen to plants.
Can inhibit plant growth, reduce soil permeability, and
contaminate ground water.
Measures a wastes ability to neutralize soil acidity.
May threaten public health by migrating to ground water or being
carried off-site by surface water, wind, or vectors.
May present public health risk through ground-water
contamination, direct contact with waste-soil mix, transport by
surface water, and accumulation in plants. Metals inhibit plant
growth and can be phytotoxic at elevated concentrations. Zinc,
copper, and nickel are micronutrients essential to plant growth,
but may inhibit growth at high levels.
total solids content (for some dry, fine, panic-
ulate wastes, conditioning may involve
adding water, such as cement kiln dust).4
Understanding the total solids content will
help plan appropriate storage and handling
procedures and establish an application rate.
Total solids content also will affect the choice of
application method and equipment. Some
methods, such as spray irrigation, may not
work effectively if the solids content is too
high. If it is low, meaning liquid content is cor-
respondingly high, waste transportation costs
could increase. If the total solids content of the
waste is expected to vary, select equipment to
accommodate materials with a range of solids
contents. For example, selecting spreaders that
will not dog if the waste is slightly drier than
Source: Ag-Chem Equipment Co., Iric.
Reprinted with permission
4Some states consider composted materials to be no longer wastes. Consult with the regulatory agency for
applicable definitions.
7C-5
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Protecting Ground Water—Designing A Land Application Program
Source: Ag-Chem Equipment Co., Inc.
Reprinted with permission
usual will help operations run more efficiently
and reduce equipment problems.
C pH
A waste's pH is a measure of its acidic or
alkaline quality. Most grasses and legumes, as
well as many shrubs and deciduous trees,
grow best in the soil pH range from 5.5 to
7.5. If a waste is sufficiently acidic or
alkaline5 to move soil pH out of that range, it
may hamper plant growth. Acidic waste pro-
motes leaching of metals, because most met-
als are more soluble under acidic conditions
than neutral or alkaline conditions. Once in
solution, the metals would be available for
plant uptake or could migrate to ground
water. Alkaline conditions inhibit movement
of most metals. Extreme alkalinity, where pH
is greater than 11, impairs growth of most
soil microorganisms and may increase the
mobility of zinc, cadmium, and lead.
Waste with a pH of 2 or less or a pH of
12.5 or more, meets the definition of haz-
ardous waste under federal regulations. If the
pH of a waste makes it too acidic for land
application, consider adjusting waste pH
before application. Lime is often used to raise
pH, but other materials are also available.
The pH is also important to consider as han-
dling and storage procedures for a waste are
planned.
D. Biodegradable Organic
Matter
Wastes containing a relatively high per-
centage of biodegradable-organic matter have
greater potential as conditioners to improve
the physical properties of soil. The percentage
of biodegradable organic'matter in soil is
important to soil fertility, as organic matter
can add nutrients; serve as an absorption and
retention site for nutrients; and provide
chemical compounds, such as chelating
agents, that help change nutrients into more
plant-available forms. Biodegradable organic
matter content is typically expressed as a per-
centage of sample dry weight.
Biodegradable organic matter influences
soil characteristics. Soils with high organic
matter content often have a darker color
(ranging from brown to black), increased
cation exchange capacity—or capacity to take
up and give off positively charged ions—and
greater water holding capacity. Biodegradable
organic matter also helps stabilize and
improve the soil structure, decrease the den-
sity of the material, and improve aeration in
the soil. In addition, organic nutrients are less
likely than inorganic nutrients to leach.
How can biodegradable organic
matter affect the waste applica-
tion rate?
While organic materials provide a signifi-
cant source of nutrients for plant growth,
decomposition rates can vary significantly
among materials. Food processing residues,
for example, generally decompose faster than
denser organic materials, such as wood chips.
Account for the decomposition rate when
determining the amount and frequency of
waste application. Loading the soil with too
much decomposing organic matter (such as
by applying new waste before a previous
5A pH of 7 is neutral. Materials with pH less than 7 are acidic, while those with pH greater than 7 are
alkaline
706
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Protecting Ground Water—Designing A Land Application Program
application of slowly decomposing waste has
broken down) can induce nitrogen deficiency
(see section E. below) or lead to anaerobic
conditions.
E. Nutrients
Nitrogen, phosphorus, and potassium are
often referred to as primary or macronutri-
ents and plants use them in large amounts.
Plants use secondary nutrients, including sul-
fur, magnesium, and calcium, in intermediate
quantities. They use micronutrients, includ-
ing iron, manganese, boron, chlorine, zinc,
copper, and molybdenum, in very small
quantities. Land application is often used to
supply nutrients, especially primary nutri-
ents, in an effort to improve plant growth.
Nutrient levels are key determinants of
application rates. Excessive soil nutrient lev-
els, caused by high waste application rates,
may be phytotoxic or result in contamination
of ground water, soil, and surface water.
Nutrient loading is dependent on nutrient
levels in both the waste and the soil, making
characterization of the soil, as well as of the
waste, important.
Nitrogen. Nitrogen content is often the pri-
mary factor determining whether a waste is
agriculturally suitable for land application,
and, if so, at what rate to apply it.
Nitrogen deficiency is detrimental to the
most basic plant processes, as nitrogen is
an essential element for photosynthesis.
Sufficient nitrogen promotes healthy
growth and imparts a dark green color in
vegetation. Lack of nitrogen can be identi-
fied by stunted plant growth and pale
green or yellowish colored vegetation.
Extreme nitrogen deficiency may cause
plants to turn brown and die. On the other
extreme, excessive nitrogen levels may
result in nitrate leaching, which can conta-
minate ground-water supplies.
Although nitrate poses the greatest threat
to ground water, nitrogen occurs in a vari-
ety of forms including ammonium, nitrate,
nitrite, and organic nitrogen. These forms
taken together are measured as total nitro-
gen. As a nutrient management plan is
developed, consider that nitrogen transfor-
mations among these forms can continue
after waste has been applied.
Phosphorus. Phosphorus plays a role in
the metabolic process and reproduction of
plants. When soil contains sufficient quan-
tities of phosphorus, root growth and plant
maturation improve. Conversely, phospho-
rus-deficient soils can cause stunted plant
growth. Excessive phosphorus can lead to
inefficient use of other nutrients and at
extreme levels, zinc deficiency.
Potassium. Potassium is an essential nutri-
ent for protein synthesis and fluid balance
in plant growth. As with other nutrient
deficiencies, symptoms include yellowing,
burnt, or dying leaves, as well as stunted
plant growth. In addition, signs of potassi-
um deficiency include reduced disease
resistance and reduced winter hardiness in
certain plants.
How can I take nutrient levels
into account?
Develop a nutrient management plan that
accounts for the amount of nitrogen, phos-
phorus, and potassium being supplied by all
sources at a site. The deciding nutrient is
often nitrogen; however, do not overlook
loading rates of other nutrients. If waste
application rates are based solely on nitrogen
levels, resulting levels of other nutrients can
exceed crop needs or threaten ground water.
Avoid excessive nutrient levels by monitoring
waste concentrations and soil buildup of
nutrients and reducing the application rate as
7C-7
-------
• Pro
Protecting Ground Water—Designing A Land Application Program
necessary; or by spacing applications to allow
plant uptake between applications.
Maintaining appropriate phosphorus and
potassium levels should be pan of an overall
nutrient management plan. The regional,
state, or county agricultural extension ser-
vices may have already developed materials
on or identified software for nutrient manage-
ment planning. Consult with them about the
availability of such information. Northeast
Regional Agricultural Engineering Services
(NRAES) Cooperative Extension, for example,
has compiled information on nutrient man-
agement software programs.6
F. Metals
A number of metals are included in the
EPAIWEM for evaluating ground-water risk.
Some metals, such as zinc, copper, and man-
ganese, are essential soil micronutrients for
plant growth. These are often added to inor-
ganic commercial fertilizers. At excessive con-
centrations, however, some of these metals may
be toxic to humans, animals, and plants. High
concentrations of copper, nickel, and zinc, for
example, cause phytotoxicity or inhibit plant
growth. Also, the uptake and accumulation of
metals in plants depends on a variety of plant
and soil factors, including pH, biodegradable
organic matter content, and cation exchange
capacity. Therefore, evaluate levels of these met-
als in waste, soil, and plants from the stand-
point of agricultural significance as well as
health and environmental risk.
How can I determine acceptable
metal concentrations?
Using the Tier 1 and II ground-water mod-
els will help to identify acceptable metals
concentrations. Also consult with the local,
state, or regional agriculture extension center
on appropriate nutrient concentrations for
plant growth. If the risk evaluation indicates
that a waste is appropriate for land applica-
tion, but subsequent soil or plant tissue test-
ing finds excessive levels of metals, consider
pretreating a waste with physical or chemical
processes, such as chemical precipitation to
remove some metals before application.
G. Carbon to Nitrogen
Ratio ;
The carbon to nitrogen ratio refers to the
relative quantities of these two elements in a
waste or soil. Carbon is associated with
organic matter, and the carbon to nitrogen
ratio reflects the level of inorganic nitrogen
available. Plants cannot use organic nitrogen,
but can absorb inorganic nitrogen, such as
ammonium. For many wastes, the carbon to
nitrogen ratio is computed as the dry weight
content of organic carbon divided by the total
nitrogen content of waste.
Some wastes rich in organic materials (car-
bon) can actually induce nitrogen deficiencies.
This occurs when wastes provide carbon in
quantities that microbes cannot process with-
out depleting available nitrogen. Soil microbes
use carbon to build cells and nitrogen to
synthesize proteins. Any excess organic nitro-
gen is then converted to inorganic nitrogen,
which plants can use. The carbon to nitrogen
ratio tells whether excess organic nitrogen will
be available for this conversion.
When the carbon to nitrogen ratio is less
than 20 to 1—indicating a high nitrogen con-
tent—organic nitrogen is mineralized, or con-
verted from organic nitrogen to inorganic
ammonium, and becomes available for plant
growth. For maximal plant growth, the litera-
ture recommends maintaining a ratio below
20 to 1. When the carbon to nitrogen ratio is
in the range of 20 to Lto 30 to 1—a low
nitrogen content—soil micro-organisms use
much of the organic nitrogen to synthesize
'Nutrient Management Software: Proceedings from the Nutrient Management Software Workshop. To order, call
NRAES at 607 255-7654 and request publication number NRAES-100.
708
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Protecting Ground Water—Designing A Land Application Program
proteins, leaving only small excess amounts
to be mineralized. This phenomenon, known
as immobilization, leaves little inorganic
nitrogen available for plant uptake. When the
carbon to nitrogen ratio is greater than 30 to
1, immobilization is the dominant process,
causing stunted plant growth. The period of
immobilization, also known as nitrogen or
nitrate depression, will vary in length
depending on the decay rate of the organic
matter in the waste. As a result, plant growth
within that range might not be stunted, but is
not likely to be maximized.
How can I manage changing
carbon to nitrogen ratios?
The cycle of nitrogen conversions within
the soil is a complex, continually changing
process. As a result, if applying waste based
only on assumed nitrogen mineralization
rates, it is often difficult to ensure that the
soil contains sufficient inorganic nitrogen for
plants at appropriate times. If you are con-
cerned about reductions in crop yield, moni-
tor the soil's carbon to nitrogen ratio and,
when it exceeds 20 to 1, reduce organic
waste application and/or supplement the nat-
urally mineralized nitrogen with an inorganic
nitrogen fertilizer, such as ammonium nitrate.
Methods to measure soil carbon include EPA
Method 9060 in Test Methods for Evaluating
Solid Waste, Physical/Chemical Methods—
SW-846. Nitrogen content can be measured
with simple laboratory titrations.
H. Soluble Salts
Soluble salts are materials that dissolve in
water or are already in solution in waste.
Major soluble salt ions include calcium (Ca2*),
magnesium (Mg2*), sodium (Na+), potassium
(KO, chloride (C1-), sulfate (SO.2-), bicarbon-
ate (HCOs-), and nitrate (NQr). The sum of
all salt ions, sugars, and other materials in
solution is referred to as total dissolved solids
(TDS). The soluble salt content of a material
may be determined by analyzing the concen-
tration of the individual constituent ions and
summing them, but this is a lengthy proce-
dure. TDS of soil or waste can reasonably be
estimated by measuring the electrical conduc-
tivity (EC) of a mixture of the material and
water. EC can be measured directly on liquid
samples. TDS is found by multiplying the
electrical conductivity reading in
millimhos/cm (mmhos/cm) by 700 to give
TDS in parts per million (ppm) or mg/1.
Soluble salts are important for several rea-
sons. First, saline soil, or soil with excessive
salt concentrations, can reduce plant growth
and seed germination. As salt concentration in
soil increases, osmotic pressure effects make it
increasingly difficult for plant roots to extract
water from the soil. Through a certain range,
this will result in reduced crop yield, up to a
maximum beyond which crops will be unable
to grow. The range and maximum for a few
representative crops are shown in Table 2. For
this reason, the salt content of the waste,
rather than its nitrogen content, can be the pri-
mary determinant of its agricultural suitability
for land application, especially on irrigated
soils in arid regions.
The second reason soluble salts are impor-
tant is that sodic soil, or soil with excessive
levels of sodium ions (Na4-) relative to diva-
lent ions (Ca2*, Mg2*), may alter soil structure
and reduce soil permeability The sodium
absorption rate (SAR) of a waste is an indica-
tor of its sodicity. To calculate the SAR of a
waste or soil, determine the Na*, Ca2*, and
Mg2+concentrations in milliequivalents per
liter7 for use in the following equation8:
SAR =
Na
V
7C-9
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Protecting Ground Water—Designing A Land Application Program
Table 2
Salinity Tolerance of Selected Crops
Soil Salinity (rnmhos/cm)i'that will result in:
Crop
0% yield
reduction
50% yield
reduction
100% yield
reduction
Alfalfa
Bermuda grass
Clover
Perennial rye
Tall fescue
2.0
6.9
1.5
5.6
3.9
8.8
14.7
10.3
12.1
13.3
16
23
19
19
32
Source: Borrelli, J. and D. Brosz. 1986. Effects of Soil Salinity on Crop Yields.
•A rule of thumb from the irrigation industry holds that soil salinity will be 11/2 times the salinity of
applied irrigation water. The effect that waste salinity will have on soil salinity, however, is not as easily
predicted and depends!on the waste's water content and other properties and on the application rate.
'Reductions are stated as a percentage of maximum expected yield.
Soils characterized, by both high salts
(excessive TDS as indicated by EC) and
excessive sodium ions (excessive Na* as indi-
cated by SAR) are called saline-sodic soils,
and can be expected to have the negative
characteristics of both saline soils and sodic
soils described above. Table 3 displays EC
and SAR levels indicative of saline, sodic, and
saline-sodic soils. The third reason soluble
salts are important is that specific ions can
induce plant toxicities or contaminate ground
water. Sodium and chloride ions, for exam-
ple, can become phytotoxic at high concen-
trations. To assess sodic- or toxic-inducing
characteristics, conduct an analysis of specific
ions in addition to measuring EC.
What can I do if a waste is
either saline or sodic?
Saline Waste. If a waste is saline, careful
attention to soil texture, plant selection, and
application rate and timing can help. Coarse
soils often have a lower clay content and are
less subject to sodium-induced soil structure
problems. While coarse soils help minimize
soil structural problems associated with salin-
ity, they also have higher infiltration and per-
meability rates, which allow for more rapid
percolation or flushing of the root zone. This
may increase the risk of waste constituents
being transported to ground water.
Since plants vary in their tolerance to
saline environments, plant selection also is
7C-10
The term milliequivalents per liter (meq/1) expresses the concentration of a dissolved substance in terms
of its combining weight. Milliequivalents are calculated for elemental ions such as Na*, Ca2*, and Mg2* by
multiplying the concentration in mg/1 by the valence number (1 for Na+, 2 for Ca2+ or Mg2+) and dividing
by the atomic weight (22.99 for Na% 40.08 for Ca2*, or 24.31 for Mg2*).
*If the proper equipment to measure these concentrations is not available, consider sending soil and
waste samples to a soil testing laboratory, such as that of the local extension service (refer to Appendix 1
for contact information) or nearby university. Such a laboratory will be able to perform the necessary
tests and calculate the SAR.
-------
Protecting Ground Water—Designing A Land Application Program
Table 3
EC and SAR Levels Indicative of Saline, Sodic, and Saline-Sodic Soils
Soil Characterization
Normal Saline Sodic Saline-Sodic
ECa< 4 and
SARb< 13
EC>4
SAR>13
EC> 4 and
SAR> 13
Source: Fipps, G. Managing Irrigation Water Salinity In the Lower Rio Grande Valley.
"In units of mmhos/cm bdimensionless
important. Some plant species, such as rye
grass, canary grass, and bromegrass, are only
moderately tolerant and exhibit decreased
growth and yields as salinity increases. Other
plants, such as barley and bermuda grass, are
more saline-tolerant species.
Avoid applying high salt content waste as
much as possible. For saline wastes, a lower
application rate and thorough, tilling or
plowing may help dilute the overall salt con-
tent of the waste by mixing it with a greater
soil volume. To avoid the inhibited germina-
tion associated with saline soils, it also may
help to time applications of high-salt wastes
well in advance of seedings.
Sodic Waste. SAR alone will not tell how
sodium in a waste will affect soil permeabili-
ty; investigate the EC of a waste as well. Even
if a waste has a high SAR, plants may be able
to tolerate this level if the waste also has an
elevated EC. As with saline waste, for sodic
waste select a coarser-textured soil to help
address sodium concerns. Adding gypsum
(CaSO4) to irrigation water may also help to
reduce the SAR, by increasing soil calcium
levels. Although this may help address sodi-
um-induced soil structure problems, if choos-
ing to add constituents to alter the SAR, the
EC will also need to be monitored to ensure
salinity levels are not increase too much.
I. Calcium Carbonate
Equivalent
Calcium carbonate equivalent (CCE) is
used to measure a waste's ability to neutralize
soil acidity—its buffering capacity—as com-
pared with pure calcium carbonate. Buffering
capacity refers to how much the pH changes
when a strong acid or base is added to a solu-
tion. A highly buffered solution will show
only a slight change in pH when strong acids
or bases are added. Conversely, if a solution
has a low buffering capacity, its pH will
change rapidly when a base or acid is added
to it. If a waste has a 50 percent CCE, it
would need to be applied at twice the rate of
pure calcium carbonate to achieve the same
buffering effect.
J. Pathogens
Potential disease-causing micro-organisms or
pathogens, such as bacteria, viruses, protozoa,
and the eggs of parasitic worms, may be pre-
sent in certain wastes. Standardized testing pro-
cedures are available to help determine
whether a waste contains pathogens. Consider
using such tests especially if process knowledge
indicates that a waste might contain pathogens.
Fecal coliform bacteria can be quantified, for
example, by using a membrane filtering tech-
nique, which involves passing liquid waste
through a filter, incubating the filtrate (which
7C-11
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Protecting Ground Water—Designing A Land Application Program
contains the bacteria) on a culture medium for
24 hours, and then counting the number of
bacterial colonies formed.
Pathogens present a public health hazard
if they are transferred to food or feed crops,
contained in run-off to surface waters, or
transported away from a land application site
by vectors. If pathogen-carrying vectors are a
concern at a site, establish measures to con-
trol them. For examples of mediods to con-
trol vectors, refer to the chapter on operating
the waste management system.
How can I reduce pathogenic
risks?
Methods to reduce pathogenic risk include
disinfecting or stabilizing a waste prior to
land application. Examples of treatment
methods recognized for sewage sludge stabi-
lization are included in the sidebar. The ser-
vices of a qualified engineer may be neces-
sary to design an appropriate process for
reducing pathogens in a waste. Consult with
the state to determine whether there are any
state-specific requirements for pathogen
reductions for specific waste types.
III. Soil Properties
Physical, biological, and chemical character-
istics of the soil are key factors in determining
soil capacity for waste attenuation. If the soil is
overloaded, rapid oxygen depletion, extended
anaerobic conditions, and die accumulation of
odorous and/or phytotoxic end-products could
impair soil fertility and productivity over the
long term as well as negatively impact adjacent
properties. With proper design and operation,
waste can be successfully applied to almost any
soil; however, sites widi highly permeable soil,
such as sand; highly impermeable soil, such as
day; poorly drained soils; or steep slopes may
Wbiat are methods for stabilizing waste
prior to land application?
The following methods, recommended
for stabilizing sewage sludge, may also be
useful for reducing pathogens in waste:
vi- ff
• Aerobic digestion
• Air drying
• Anaerobic digestion ' '*
• Composting, and
• lime stabilization
, More detailed information on each of ,,
these and other methods can be found
in EE/& Control of Pathogens and Vector
'Attraction in Sewage Sludge
(EPA625-R-92-013).
present special design issues. Therefore, give
such sites lower priority during the site selec-
tion process.
How can I evaluate the soil at a
site?
To help evaluate the soil properties of a
site, consult the U.S. Department of
Source: Ag-Chem Equipment Co., Inc.
Reprinted with permission
Agriculture (USDA) soil survey for the
prospective area. These surveys provide infor-
mation on properties such as soil type and
permeability USDA has prepared soil surveys
for most counties in each state. To obtain a
copy of the survey for an area, contact the
Natural Resource Conservation Service offices,
7C-12
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Protecting Ground Water—Designing A Land Application Program
the county conservation district, agricultural
cooperative extension service (refer to
Appendix I for contact information), local
health authorities, or planning agency. These
soils surveys will help during site selection;
however, conditions they describe may differ
from the actual soil conditions.
For more site-specific data on actual soil
conditions, sample and characterize the soil.
It may be desirable to have a qualified soil
scientist perform this characterization, which
often investigates soil texture, percentage of
organic matter, depth to water table, soil pH,
and cation exchange capacity. At a minimum,
characterize samples from an upper soil layer,
0 to 6 inches, and a deeper soil layer, 18 to
30 inches, and follow established soil sam-
pling procedures to obtain meaningful
results. If a detailed characterization is
desired, or if it is suspected soil types vary
considerably, further subdivision of soil hori-
zons or collection of samples over a greater
variety of depths might be appropriate. For
more information about how to obtain repre-
sentative soil samples and to submit them for
analysis, consult federal manuals, such as
EPA's Laboratory Methods for Soil and Foliar
Analysis in Long-Term Environmental
Monitoring Programs (EPA600-R-95-077) or
state guides, such as Nebraska's Guidelines for
Soil Sampling, G91-1000.
Why are chemical and biological
properties of soil important?
Chemical and biological properties of the
soil, like those of the waste, influence soil
attenuation of waste constituents. These
properties include pH, percentage of organic
matter, and cation exchange capacity. Affected
attenuation processes in the soil include
absorption, adsorption, microbial degrada-
tion, biological uptake, and chemical precipi-
tation. For example, adsorption—the process
by which molecules adhere to the surface of
other particles, such as clay—increases as the
cation exchange capacity and pH of the soil
increase. Cation exchange capacity, in turn, is
dependent on soil composition, increasing as
the clay content of the soil increases.
Absorption through cation exchange is an
important means of immobilizing metals in
the soil. Organic chemicals, on the other
hand, are negatively charged and can be
adsorbed through anion exchange, or the
exchange of negative ions. A soil's capacity
for anion exchange increases as its pH
decreases.
Why are physical properties of
soil important?
Physical properties, such as texture, struc-
ture, and pore-size distribution, will affect
infiltration and the capability of soil to filter or
entrap waste constituents. Infiltration and per-
meability rates decrease as clay content
increases. Sites with soils that have too high or
too low permeability have lower land applica-
tion potential. Soils with high permeability
may allow wastes to move through without
adequate attenuation. Soils with low perme-
ability can cause pooling or excessive surface
run-off during intense rainstorms. Excessive
run-off conditions can be compensated for
somewhat by minimizing surface slope during
site selection. Soils with low permeability are
also prone to hydraulic overloading.
The amount of liquid that can be assimilated
by a soil system is referred to as its hydraulic
loading capacity. In addition to a soil's perme-
ability, hydraulic loading capacity is dependent
on other factors such as climate, vegetation, site
characteristics, and other site-specific soil prop-
erties such as soil types, depth to seasonally
high water table, slope and erodibility water
intake rates, and underlying geology and hydro-
geology Exceeding the hydraulic loading
7C-13
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Protecting Ground Water—Designing A Land Application Program
capacity of a site, hydraulic overloading, may
lead to rapid leaching of waste constituents into
ground water, reduction in biological activity,
sustained anaerobic conditions, soil erosion,
and possible contamination of surface waters. It
may also result in evaporation becoming
responsible for a significant part of waste treat-
ment. This can cause excessive odor and
unwanted airborne emissions. In order to avoid
hydraulic overloading at a site, application of
liquid or semi-liquid waste or wastewater
should be managed so uncontrolled run-off or
prolonged saturation of the soil does not occur.
Topography influences surface and subsur-
face water movement, which affects the
potential for soil erosion and contaminated
surface water run-off. Topography also can
indicate the kinds of soil found on a site.
Soils on ridge tops and steep slopes are typi-
cally well drained, well aerated, and shallow.
Steep slopes, however, increase the likelihood
of surface^ run-off of waste and of soil erosion
into surface waters. State guidelines, there-
fore, often specify the maximum slopes
allowable for land application sites for vari-
ous waste characteristics, application tech-
niques, and application rates. The agencies
that regulate land application in a state can
provide specific guidance concerning slopes.
Soils on concave land and broad flat lands,
on the other hand, frequently are poorly
drained and may be waterlogged during part
of the year. Soils in relatively flat areas may
have intermediate properties with respect to
drainage and run-off and could be more suit-
able for land application.
IV. Plant and
Microbial Effects
The next step is to consider the crops that
will grow on the site. This is important for
several reasons. First, uptake of nutrients9 by
plants (and by microbes on plant roots or in
soil) affects the rate of waste assimilation and
biodegradation, usually increasing it. Second,
the waste affects plant and microbes growth.
In addition, certain waste characteristics,
such as the presence of pathogens or toxic
constituents, may render crops unusable for
food or feed. It may be necessary to conduct
greenhouse or field studies or other tests of
plants, soil and microbes to understand and
quantify these interactions. Consult with the
state agricultural department, health depart-
ment, and other appropriate agencies if con-
sidering land-application of wastes contain-
ing designated ground-water constituents or
other potentially harmful properties to food
or feed crops. Industry groups may also be
able to provide information about plants with
which they have land application experience.
A. Greenhouse and Field
Studies
State agricultural extension services,
departments of environmental protection, or
public universities may have previous studies
about plant uptake of nutrients, especially
nitrogen, phosphorus and potassium, but it is
important to recognize that the results of
studies conducted under different conditions
(such as different waste type, application
rates, plant type, or climate) are only partially
relevant to a specific situation. Furthermore,
most studies to date have focused on relative-
ly few plant species, such as corn, and only a
handful of constituents, typically metals.
Greenhouse studies or pilot-scale field studies
attempt to model site-specific conditions by
growing the intended crops in soil from the
prospective application site. These studies are
useful because individual parameters can be
varied, such as plant type and waste applica-
tion rate, to determine the effects of each fac-
tor. Additionally, greenhouse or field studies
may be required by some states to certify that
f
-------
Protecting Ground Water—Designing A Land Application Program
a waste has agricultural benefits. The first
point of contact for assistance with studies is
the state agricultural extension service. Many
state extensions can conduct these studies;
others may be able to provide guidance or
expertise but will recommend engaging a pri-
vate consultant to conduct the studies.
How do I conduct greenhouse
or field studies?
Currently, no national guidelines exist for
conducting greenhouse and/or field studies10
but check to see if the state has guidance on
accepted practices. Working with a state agri-
cultural extension service or a local university
will provide the benefit of their expertise and
experience with local conditions, such as
which plants are suitable for local soils and cli-
mate. If a particular industry sector has a large
presence in a state, the state agricultural exten-
sion service may have previous experience
with that specific type of waste.
Greenhouse Studies. Aside from their
smaller scale, greenhouse studies differ
from field studies primarily in that they are
conducted indoors under controlled condi-
tions, while field studies are conducted
under natural environmental conditions. A
greenhouse study typically involves dis-
tributing representative soil samples from
the site into several pots to test different
application rates, application methods, and
crops. Using several duplicate pots for
each rate, method, or crop allows averag-
ing and statistical aggregating of results. It
is also important to establish control pots,
some with no waste and no plants, others
with waste but no plants (to observe the
extent to which waste assimilation effects
are due to soil and pre-existing microbes)
and still others with plants but without
waste (as a baseline for comparison with
waste-amended plant growth).
To the extent feasible, temperature, mois-
ture, and other parameters should simulate
actual site conditions. There should be a
series of several duplicate pots grown with
each combination of plant type, applica-
tion rate, and other parameters. Pots
should be arranged to avoid environmental
conditions disproportionately affecting one
series of pots. For example, avoid placing a
whole series of pots in a row closest to a
light source; instead, place one pot from
each of several series in that row or ran-
domize placement of pots.
The controlled greenhouse environment
allows the study of a wide range of waste-
soil interactions without risking loss of
plants due to weather, animal hazards, and
other environmental influences. At the
same time, this may introduce differences
from actual conditions. Root confinement,
elevated soil temperature, and rapidly
changing moisture levels, for example, may
increase the uptake of pollutants by potted
plants compared to uptake under field
conditions.11
Field Studies. Field studies, on the other
hand, test various application rates and suit-
able crops on plots at the proposed site. As
with greenhouse studies, duplicate plots are
useful for statistical purposes and controls
are needed. Field study data may be found
to be more useful because it more closely
reflects real-world conditions, but more dif-
ficult to obtain if extreme environmental
events (such as flooding or unusual pest
damage) occur at the time of the study Field
studies may also be subject to siting, health
and safety and permitting requirements.
Field studies also help determine the actual
land area required for land application and
the quality of run-off generated. Soil and
ground-water monitoring help to confirm
"Based on conversations with Dr. Rufus L. Chancy and Patricia Milner. U.S. Department of Agriculture.
7C-15
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Protecting Ground Water—Designing A Land Application Program
that waste constituents are being taken up
by plants and not leaching into the ground
water. Results from field studies, however,
• might not be duplicated on actual working
plots after multiple waste applications, due
to long-term soil changes. Crop yields also
may vary by as much as 15 to 25 percent
under field conditions, even with good fer-
tility and management.
Both greenhouse and field studies typically
include extensive sampling of waste, soil
before application, plants or representative
parts of plants, soil after application and
growth of plants, and, to the extent feasible,
water. Sample soil at the surface and in lower
horizons using core sampling. Some soil tests
require mixing samples with water to form a
paste or slurry. Plant tissue tests often require
dry-weight samples, made by drying cut
plants at about 65 °C. Water can be collected
in lysimeters (buried chambers made from
wide perforated pipe) and removed using
hand pumps.
i
Monitoring waste effects on organisms in
the soil during greenhouse and field studies
is also possible. For example the literature
suggests that effects of waste on earthworms
are a good indicator of effects on soil organ-
isms in general. It may be worthwhile, there-
fore, to stock greenhouse pots or field study
plots with earthworms at the beginning of a
study and monitor the waste constituent lev-
els in and effects on the worms during and at
the end of the study. Although these brief
studies will not effectively model long-term
exposure to waste constituents, it is possible
to gauge short-term and acute effects.
B. Effects of Plants and
Microbes on Waste
Assimilation
After performing studies, measure the
amounts of various nutrients, metals, and
other constituents in tissue samples from
plants grown in the greenhouses or on test
plots. This tells approximately how much of
these constituents the plants extracted from
the soil-waste mix. By measuring plant-
extracted quantities under these various con-
ditions, you can determine a relationship
between plant type, application rate, and
nutrient extraction. From this, choose the
conditions which result in the desired uptake
rate while avoiding uptake of designated
ground-water constituents at undesirable
concentrations.
In choosing plants for a land application
unit, consider growing seasons in relation to
periods of peak waste generation. If greenhouse
or field studies indicated that a specific waste
application rate associated with a corresponding
uptake of nutrients by plants, this will be the
case only during the growth phases covered by
the study. At other times waste application may
be infeasible because plants are not present to
help assimilate waste, or because plants are too
"If a waste contains VOCs, ensure the possibility of VOCs accumulating within th? enclosed greenhouse
is addressed.
7C-16
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Protecting Ground Water—Designing A Land Application Program
large to permit passage of application equip-
ment without sustaining damage.
Certain microbes can biodegrade organic
chemicals and other waste constituents. Some
accomplish this by directly using the con-
stituents as a source of carbon and energy,
while others co-metabolize constituents in
the process of using other compounds as an
energy source. Aerobic microorganisms
require oxygen to metabolize waste and pro-
duce carbon dioxide and water as end prod-
ucts. Anaerobic microbes function without
oxygen but produce methane and hydrogen
sulfide as end products. These gases can pre-
sent a safety risk as well as environmental
threats, and hydrogen sulfide is malodorous.
For these reasons, maintain conditions that
favor aerobic microbes.
For many microorganisms, these condi-
tions include a pH of 6 to 8 and temperatures
of 10 °C to 30 °C. In addition, microbes may
be unable to transfer oxygen from soil effi-
ciently if the moisture content is near satura-
tion or they may be unable to obtain suffi-
cient water if the soil is too dry. A water con-
tent of 25 to 85 percent of the soil's water
holding capacity is recommended in the liter-
ature. Oxygen generally is available through
diffusion from the atmosphere, but this
mechanism may provide insufficient oxygen
if there is too little pore space (less than 10
percent of soil volume) or if so much organic
matter is applied that oxygen is consumed
faster than it is replaced.
duction, which is the dry weight of the cut
plants (or representative parts of the plants). If
the plants grown with waste applications show
greater mass than the control plants12, the
waste may be providing useful nutrients or
otherwise improving the soil. If the plants
grown with waste applied at a certain rate
weigh less than the controls, some con-
stituent(s) in the waste may be excessive at the
studied application rate. Comparing the results
from several different application rates may
help find the rate that maximizes growth and
avoids detrimental and phytotoxic effects.
Analyzing soil and water after plant growth
allows for a comparison between the planted
pots or plots against the control to discern
the differences due to plant action. If water
samples show excessive nutrient (especially
nitrogen) levels at and above a certain appli-
cation rate, this may indicate that the plants
were unable to use all the nutrients in die
waste applied at that rate, suggesting that the
application was excessive.
To check for microbial action, compare the
control pots or plots with no waste and no
plants grown to those widi waste and no plants
grown. If soil and water tests show that con-
stituents are consumed, and if other possible
causes can be ruled out, microbes might be
responsible. If further investigation of microbial
action is desired, laboratory methods allow
sampling of microbes in soil, counting their
population, and direct measurement of waste
constituents and degradation byproducts.
C. Effects of Waste on
Plant and Microbe
Growth
Greenhouse and field studies can tell what
effect the waste will have on plant growth pat-
terns. A typical method of quantifying plant
growth is to state it in terms of biomass pro-
D. Grazing and Harvesting
Restrictions
If a waste may contain pathogens or desig-
nated ground-water constituents, and the
established vegetative cover on the land
application site is intended for animal con-
sumption, it is important to take precautions
to minimize exposure of animals to these
"Trends detected in studies assume that results have been subjected to tests of statistical validity before
finding a trend significant.
7C-17
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Protecting Ground Water—Designing A Land Application Program
contaminants. This is important because ani-
mals can transport pathogens and these
ground-water constituents from a site to oth-
ers, and can also act as an entry point of
bioaccumulated waste constituents and
pathogens into the food chain, or into
humans if the animals are intended for
human consumption.
If harvesting crops from a unit for use as
animal fodder, test plants for the presence of
undesirable levels of the designated ground-
water constituents before feeding. Grazing
animals directly on a unit is discouraged by
some states13. If considering direct grazing,
consult with the state to see if there are any
restrictions on this practice. Growing crops
for human consumption on soil amended
with waste calls for even greater caution. In
some states, this practice is prohibited or reg-
ulated, and in states where it is allowed, find-
ing food processors or distributors willing to
purchase such crops may be difficult.
When testing crops before feeding them to
animals, local agricultural extension services
may be able to help determine what levels
are appropriate for animal consumption. In
addition, take into account the potential for
bioaccumulation and food chain effects. If
plant tissue samples and/or findings of a fate
and transport model (see the section on
assessing risk) indicate waste constituents
levels inappropriate for animal consumption,
do not use harvested plants as fodder or
allow grazing on the site. Additionally, plants
with high constituent levels will probably be
inappropriate for other agricultural use,
necessitating disposal of such crops as a
waste after harvest.
V. Climate
Climate considerations should enter into
the planning for land application. For exam-
ple, wastes high in soluble salts are less
appropriate in arid climates than elsewhere,
due to osmotic pressure'from salts inhibiting
root uptake of water, as discussed above. On
the other hand, downward movement of
water in the soil is minimal in arid climates,
making migration of waste constituents to
ground water less likely.
Climate also determines what plants can
grow in a region and the length of the grow-
ing season. If the climate cannot support the
plants most helpful in assimilating the partic-
ular constituents in the waste, land applica-
tion use may be limited to other crops and
waste application at a lower rate. If the cli-
mate dictates that the part of the growing
cycle during which land application is appro-
priate is short, a larger area for land applica-
tion may be necessary as well as providing
more off-season waste storage capacity.
There are also operating considerations
associated with climate. Since waste should not
be applied to frozen or very wet soil, the appli-
cation times may be severely limited in very
cold or rainy climates. In climates where the
ground can freeze, winter application poses
problems even when the ground is not frozen,
because if the ground freezes soon after appli-
cation, waste that remained near the soil sur-
face may run-off into surface waters during
subsequent thaw periods. Waste nutrients are
also more likely to leach through the soil and
into the ground water following spring thaw,
prior to crop growth and nutrient uptake.
These problems can be partially solved by pro-
viding sufficient waste storage capacity for peri-
ods of freezing or rainy weather.
VI. Agronomic Rate
The purpose of a land application unit
affects its application rate. When agricultural
benefits are to be maximized, the application
rate is governed by the, agronomic rate. The
agronomic rate is an application rate
"Grazing may also be unwise due to potential effects on soil physical stracture. The weight of heavy ani-
mals can compact soil, decreasing pore space, which may reduce the soil's waste attenuation capacity.
7C-18
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Protecting Ground Water—Designing A Land Application Program
designed to provide the amount of nitrogen
plants need to attain a desired yield, while
minimizing the amount of nitrogen that will
pass below the root zone of the crop or vege-
tation to the ground water. The agronomic
rate depends on the nitrogen content of the
waste, but the levels of phosphorus and
potassium in the waste and soil should also
be considered. In setting a preliminary appli-
cation rate, the agronomic rate often serves as
a ceiling, but in some cases, phosphorus,
potassium, or salt content, rather than nitro-
gen will be the limiting factor.
How do I determine the
agronomic rate?
Computer models can help determine site-
specific agronomic rates. Modeling nitrogen
levels in waste and soil-plant systems can
help provide information about soil physical
and hydrologic conditions and about climatic
influences on nitrogen transformations.
Models recommended for use with sewage
sludge include Nitrogen Leaching and
Economic Analysis Package (NLEAP);
DECOMPOSITION; Chemicals, Run-Off, and
Erosion from Agricultural Management
Systems (CREAMS); and Ground-Water
Loading Effects of Agricultural Management
Systems (GLEAMS)14. NLEAP uses monthly
and event-by-event approaches throughout
the year to compute water and nitrogen bud-
gets. The computer model DECOMPOSI-
TION is specifically designed to help predict
sewage sludge nitrogen transformations based
on sludge characteristics, as well as climate
and soil properties (organic matter content,
mean soil temperature, and water potential).
Finally, the CREAMS and GLEAMS models,
developed by the USDA, are other potentially
useful models to assist with site-specific man-
agement of land application operations.
Additional computer models include AMA-
NURE, Cornell Nutrient Management
Planning System (NMPS), Fertrec Plus v 2.1,
and Michigan State University Nutrient
Management vl. I13. If assistance is required
in determining an appropriate agronomic rate
for a waste, contact the regional, state, or
county agricultural cooperative extensions, or
a similar organization.
VII. Monitoring
Monitoring ground water can be helpful to
verify whether waste constituents have migrat-
ed to ground water. Some state, tribal, or other
regulatory authorities require ground-water
monitoring at certain types of land application
units; consult with the appropriate regulatory
agency to determine whether such a require-
ment applies to the unit. Even if the unit is not
required to monitor ground water, instituting a
ground-water monitoring program for long-
term, multiple application units where waste
contain the designated ground-water con-
stituents is recommended. Such units are more
14A11 of these models are referenced in EPA's Process Design Manual Land Application of Sewage Sludge and
Domestic Septage (EPA625-R-95-001). According to that source, the NLEAP software, developed by
Shaffer et al., is included in the purchase of Managing Nitrogen for Groundwater Quality and Farm
Profitability by Follet, et al., which also serves as reference for information on parameters required for
nitrogen calculations. Four regional soil and climatic databases (Upper Midwest, Southern, Northeastern,
and Western) also are available on disk for use with NLEAP. These materials can be obtained from: Soil
Science Society of America Attn: Book Order Department, 677 S. Segoe Road, Madison, WI 53711,
608/273-2021; Book $36.00; Regional Databases $10.00 each. Current updates of the NLEAP program
can be obtained by sending original diskettes to: Mary Brodahl, USDA-ARS-GPSR, Box E, Fort Collins,
CO 80522. Additional information on the DECOMPOSITION model, developed by Gilmour and Clark,
can be obtained from: Mark D. Clark, Predictive Modeling, P.O. Box 610, Fayetteville, AR 72702. The
CREAMS and GLEAMS models were developed by USDA.
15These models are referenced in the Northeast Regional Agricultural Engineering Cooperative Extension's
Nutrient Management Software: Proceedings from the Nutrient Management Software Workshop from December
11, 1996.
7C-19
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Protecting Ground Water—Designing A Land Application Program
likely to pose a threat to ground water than
are single-application units or units receiving
waste without these constituents. In most
cases, lysimeters should be sufficient to moni-
tor ground water. A lysimeter is a contained
unit of soil, often a box or cylinder in the
ground which is filled with soil, open on the
top, and closed at the bottom, so that the
water that runs through it can be collected. It
is usually more simple and economical to con-
struct and operate than a monitoring well.
Consult with a qualified professional to devel-
op an appropriate ground-water monitoring
program for a land application unit.
If ground-water results indicate unaccept-
able constituent levels, suspend land applica-
tion until the cause is identified. Then correct
the situation that led to the high readings. If
a long-term change in the industrial process,
rather than a one-time incident, caused the
elevated levels, reevaluate land application.
Adjusting die application rate, adding pre-
treatment, or switching to another means of
waste management may be necessary. After
reevaluation, examine whether corrective
action may be necessary for the ground water
already contaminated, Pay particular atten-
tion to ensure that applications are not
exceeding the soil's assimilative capacity.
Consider testing soil samples periodically
during the active life of a land application
unit. For this testing to be meaningful, first
determine baseline conditions by sampling
the soil before-waste application begins. This
may already have been done in preparation
for greenhouse/field studies or for site char-
acterization. Later, when applying waste to
the unit, collect and analyze samples at regu-
lar intervals (such as annually or after a cer-
tain number of applications). Consider ana-
lyzing samples for macronutrients, micronu-
trients, and any of the designated ground-
water constituents reasonably expected to be
present in the waste. The location and num-
ber of sampling points, frequency of sam-
pling, and constituents to be analyzed will
depend on site-specific soil, water, plant, and
waste characteristics. Local agricultural
extension services, which have experience
with monitoring, especially when coupled
with ground-water monitoring, can detect
contamination problems. Early detection
allows time to change processes to remedy
the problems, and to conduct corrective
action if necessary before contamination
becomes widespread.
Testing soils after the active life of a unit
ends may also be appropriate, especially if
the waste is likely to have left residues in the
soil. The duration of monitoring after clo-
sure, like the location and frequency of mon-
itoring during active life, is site-specific and
depends on similar factors. For further infor-
mation about testing soil after active life
ends, refer to the chapter on performing clo-
sure and post-closure care.
7C-20
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Protecting Ground Water—Designing A Land Application Program
a
a
a
a
a
a
a
a
Action Items for Designing a Land
Application Program
Use the evaluation framework to design a land application program before beginning a
ground-water risk assessment, and to help determine a preliminary waste application rate.
Be familiar with waste parameters, such as total solids content, pH, organic matter, nutrients
carbon and nitrogen levels, salts, soil buffering capacity, and pathogens.
Examine potential application sites, giving special consideration to physical and chemical
properties of soil, topography, and any site characteristics that might encourage run-off or
odor.
Choose crops for the unit, considering plant uptake of nutrients and constituents.
Account for climate and its effects.
Determine an agronomic application rate.
Evaluate ground-water and air risks from land application units and consider potential
exposure pathways.
Consider implementing a ground-water monitoring program and periodic sampling of unit
soils.
7C-21
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Protecting Ground Water—Designing A Land Application Program
Resources
Brandt, R.C. and K.S. Martin. 1996. The food processing residual management manual.
September.
Evanylo, G.K. and W L. Daniels. 1996. The value and suitability of papermill sludge and sludge
compost as a soil amendment and soilless media substitute. Final report. Virginia Department of
Agriculture and Consumer Services. April.
Fipps, G. 1995. Managing irrigation water salinity in the lower Rio Grande Valley,
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Protecting Ground Water—Designing A Land. Application Program
Resources (cent.)
Rowell, D.L. 1994. Soil science: Methods and applications.
Texas Water Commission. 1983. Industrial solid waste management technical guideline no. 5: Land
application. December.
University of Nebraska Cooperative Extension Institute of Agriculture and Natural Resources. 1991.
Guidelines for soil sampling. G91-1000-A. February.
U.S. EPA. 1995a. A guide to the biosolids risk assessments for the EPA Part 503 Rule. EPA832-B-93-
005. September.
U.S. EPA. 1995b. Process design manual: Land application of sewage sludge and domestic septage.
EPA625-R-95-OOL September.
U.S. EPA. 1995c. Process design manual: Surface disposal of sewage sludge and domestic septage.
EPA625-R-95-002. September.
U.S. EPA. 1995d. Laboratory methods for soil and foliar analysis in long-term environmental moni-
toring programs. EPA600-R-95-077.
U.S. EPA. 1994a. Land application of sewage sludge: A guide for land appliers on the requirements of
the federal standards for the use or disposal of sewage sludge, 40 CFR Part 503. EPA83 l-B-93-002b.
December.
U.S. EPA. 1994b. Guide to septage treatment and disposal. EPA625-R-94-002. September.
U.S. EPA. 1994c. A plain English guide to the EPA Part 503 biosolids rule. EPA832-R-93-003.
September.
U.S. EPA. 1994d. Biosolids recycling: Beneficial technology for a better environment. EPA832-R-94-
009. June.
U.S. EPA. 1993. Domestic septage regulatory guidance: A guide to the EPA 503 Rule. EPA832-B-92-
005. September.
U.S. EPA. 1992. Control of pathogens and vector attraction in sewage sludge. EPA625-R-92-013.
December.
7C-23
-------
Protecting Ground Water—Designing A Land Application Program
Resources (cont.)
U.S. EPA. 1990. State sludge management program guidance manual. October.
U.S. EPA. 1983. Process design manual for land application of municipal sludge. EPA625-1-83-016.
October.
U.S. EPA, U.S. Army Corps of Engineers, U.S. Department of Interior, and U.S. Department of
Agriculture. 1981. Process design manual for land treatment of municipal wastewater. EPA625-1-81-
013. October.
U.S. EPA. 1979. Methods for chemical analysis of water and wastes. EPA600-4-79-020.
Viessman Jr., W. and MJ. Hammer. 1985. Water supply and pollution control. 4th ed.
Washington State Department of Ecology. 1993. Guidelines for preparation of engineering reports for
industrial wastewater land application systems. Publication #93-36. May.
Webber, M.D. and S.S. Sing. 1995. Contamination of agricultural soils. In Action, D.E and L.J.
Gregorich, eds. The health of our soils.
Wisconsin Department of Natural Resources. 1996. Chapter NR 518: Landspreading of solid waste.
April.
7C-24
-------
Part 5
Ensuring Long-Term Protection
Chapter 8
Operating The Waste Management System
-------
Contents
1. An Effective Waste Management System [[[ 8-1
II. Maintenance and Operation of Waste Management System Components ............................................... ...8-2
A. Ground-Water Controls [[[ ................................. 8-4
B. Surface-Water Controls [[[ ................................. 8-5
C. Air Controls [[[ ................................... 8-5
III. Operational Aspects of a Waste Management System ............................................... '. .............................. ...8-8
A. Operating Plan [[[ 8'8
B. Waste Analysis [[[ 8~9
C. Waste Inspections [[[ 8-9
D. Daily Cover [[[ 8-11
E. Placing Wastes [[[ 8"11
E Climate Considerations ....... [[[ • ............................... 8~12
G. Security Measures, Access Control, and Traffic Management [[[ 8-12
-------
Ensuring Long-Term Protection—Operating The Waste Management System
Operating the Waste Management System
Develop a waste management system that includes procedures to
monitor and measure performance. The waste management system
also needs to have operational elements to achieve environmental
goals and to make continual improvements in waste management
operations.
T
,he key to safe and efficient waste
management is implementing a
waste management system that
achieves protective environmental
goals while having operational ele-
ments in place to monitor and measure perfor-
mance of the waste management operations.
Following an effective waste management sys-
tem can help ensure proper functioning of the
many interrelated systems that a unit depends
on for waste containment, leachate manage-
ment, and other important functions. If the ele-
ments of an overall waste management system
are not regularly inspected, maintained,
improved, and evaluated for efficiency, even the
best-designed unit may not operate efficiently.
Following an effective waste management sys-
tem can also reduce long- and short-term costs,
protect workers and local communities, and
maintain good relations.
This chapter will help address the .
following questions:
• What is/an effective waste management?
• What maintenance and operational
aspects should be developed as a part
of a waste management system?
I. An Effective
Waste
Management
System
Having an effective waste management sys-
tem requires an understanding of environ-
mental laws and an understanding of how
best to achieve compliance with these laws.
An effective waste management system also
requires that procedures be in place to moni-
tor and measure performance in complying
with environmental laws. Lastly, an effective
waste management system involves opera-
tional procedures that seek to make continual
improvements in waste management opera-
tions so that compliance with environmental
laws is an ongoing accomplishment.
In addition to what is discussed in this chap-
ter, consider reviewing and implementing the
draft voluntary standards for good environmen-
tal practices developed by the International
Standards Organization (ISO), as appropriate.
The ISO 14000 series standards identify man-
agement system elements that are intended to
lead to improved performance: a method to
identify significant environmental aspects; a pol-
icy that includes a commitment to regulatory
8-1
-------
Ensuring Long-Term Protection—Operating The Waste Management System
compliance, the prevention of pollution, and
continual improvement; environmental objec-
tives and targets for all relevant levels and func-
tions in the organization; procedures to ensure
performance, as well as compliance procedures
to monitor and measure performance; and a
systematic management review process.
The ISO 14000 series' of standards include
"specification" standard, ISO 14001, The rest
are guidance standards which provide optional
guidance for companies developing and imple-
menting management systems and product
standards. The ISO 14001 specification stan-
dard contains only those requirements that may
be objectively audited for certification/registra-
tion purposes and/or self declaration purposes.
For more information about EPA's involvement
in the ISO 14000 and 14001 standards, see
Appendix A: ISO 14000 Resource Directory,
October 1997, EPA625-R-97-003.
Additional Information on ISO 14000
The ISO 14000 series of standards are
copyrighted and can be obtained by con-
tacting any of the following organizations:
ANSI
7315 Wisconsin Avenue, Suite 250-E
Bethesda, MD 20814
301 469-3363
ASTM
100 Bar Harbor drive
West Conshohocken, PA 19428
610 832-9721
ASQC
611 East Wisconsin Avenue
RO, Box 3005
Milwaukee, WI 53201
NSF International
2100 Commonwealth Boulevard
Ann Arbor, Michigan 48105
313 332-7333
II. Maintenance
and Operation of
Waste
Management
System
Components
All of the work that has gone into planning,
designing, and developing a unit will be jeopar-
dized if proper site operations are not carried
out. Operation is important for reasons of envi-
ronmental protection, economy, efficiency, and
esthetics. Operating control systems, therefore,
need to be developed and maintained to ensure
efficient and protective operation of a waste
management system. These controls include
conducting frequent inspections, performing
routine maintenance, reporting of inspection
results, and making necessary improvements to
keep the system operating.
Unit inspections can help identify deterio-
ration of or malfunction in control systems.
Surface impoundments should be inspected
for evidence of overtopping, sudden drops in
liquid levels, and deterioration of dikes or
other containment devices. Overtopping, or
the flowing of waste over the top of the walls
of the impoundment, occurs as a result of
insufficient freeboard, wind or wave action, or
other unusual conditions. Make visual inspec-
tions periodically to check waste levels,
weather conditions, or draining during peri-
ods of heavy precipitation. In addition, con-
sider devising a contingency plan to reinforce
dikes when failure is imminent.
Waste piles and landfills should be inspect-
ed for adequate surface-water protection sys-
tems, leachate seeps, dust suppression meth-
ods, and daily covers, if applicable. Land
application sites should be inspected for ade-
quate surface-water protection systems and
8-2
-------
Ensuring Long-Terra Protection—Operating The Waste Management System
dust suppression methods, if applicable. If
conducted regularly, inspections of safety,
emergency, and security devices; monitoring
equipment; pipes; and mechanical equipment
also will help ensure that a unit operates in a
safe manner. In addition, inspections often
prevent small problems from growing into
more costly ones.
the inspection log to identify any malfunc-
tions or deficiencies that remain uncorrected
from previous inspections. The sample log is
a unit-independent template. When design-
ing an inspection form for a unit, add appro-
priate items for the unit type. Check with the
state to see if it has an inspection form that
can be used. For example, a landfill form
How should effective
inspections be conducted?
To help ensure that routine
inspections are performed regularly
and consistently, consider develop-
ing a written inspection schedule
and ensure that staff follow the
schedule. The schedule could state
the type of inspections to be con-
ducted, the inspection methods to
be used, the frequency of the inspec-
tions, and a plan of action highlight-
ing preventative measures to address
potential problems. Consider con-
ducting additional inspections after
extraordinary site-specific circum-
stances, such as storms or other
extreme weather conditions.
Staff conducting the inspections
should look for malfunctioning or
deteriorating equipment, such as
broken sump pumps, leaking fit-
tings, eroding dikes, or corroded
pipes or tanks; discharges or leaks
from valves or pipes; and operator
errors. A written schedule for
inspections should be maintained at
the facility, and inspections should
be recorded in a log (see Figure 1)
containing information such as date
of inspection, name of inspector,
conditions found, and recommend-
ed corrective action. Inspection
personnel should be familiar with
Figure 1. Example Inspection Log
Site Inspection Form
XYZ Industries • Waste Management Unit 1a • 123 Paved Road • Anytown, US 56789
Location Inspected:.
Name(s) of
Inspector^):
Temperature:_
Conditions:
. Date: / /
Wind:_
Precipitation^
Other
TRAFFIC MANAGEMENT
Vehicle stacking room
Collector working efficiently
Route to active area clearly marked
Access to road in good condition
Spotter properly placing vehicles
Truck wash and its drain working
Covers/seals on trucks
Route to active area clearly marked
Acceptable Unacceptable Notes
O
D
n
n
n
n
n
D
COVER OPERATION
Cover material suitable and sufficient d
Waste covered to design depth D
ADC is being properly used D
DRAINAGE
No ponded water D
No signs of erosion D
Erosion control systems working D
No leachate seeps D
All runoff flows to design endpoint D
Contact water handled as leachate D
SAFETY
Emergency response plan up-to-date D
Fences/gates maintained and locked D
Warning signs in place and readable D
Speed limits observed D
Scavenging not evident D
NUISANCE CONTROL
Odor controls working D
Dust controls working Q
Vector controls working D
Noise controls working D
No waste/mud on public roads D
Comments, observations, or problems_
Q
D
n
O
a
D
a
D
n
a
o
a
D
a
D
D
a
D
D
a
o
n
a
D
a
a
n
8-3
-------
Ensuring Long-Tenn Protection—Operating The Waste Management System
would include a section about waste place-
ment and a surface impoundment form might
have an entry for sufficient freeboard. If
ground water is monitored, consider making
ground-water monitoring part of the unit
inspection, and add check boxes for each
monitoring point to ensure that inspectors col-
lect samples from all monitoring points.
Ensure that all inspection reports are
reviewed soon after the inspection so that any
necessary repairs and improvements can be
quickly identified and implemented. Consult
the state to help determine if improvements
are necessary.
A. Ground-Water Controls
Ground-water protection controls, such as a
ground-water monitoring systems, unit covers,
and leachate detection and collection systems
should be incorporated into the design and
construction of a unit, as well as routine unit
inspections. Ground-water monitoring wells
require continued maintenance. A major rea-
son for maintenance is plugging of the gravel
pack or screen. (See the chapter on monitor-
ing performance for a discussion on the con-
struction of ground-water monitoring wells.)
The most common plugging problems are
caused by precipitation of calcium or magne-
sium carbonates and iron compounds. Acid is
most commonly used to clean screens clogged
with calcium carbonate. In many instances,
however, the cost of attempted restoration of a
monitoring well may be more than the instal-
lation of a new well. Because many wells are
installed in unconsolidated sand .formations,
silt and clay can be pumped through the sys-
tem and cause it to fail. Silt and sand grains
are abrasive and can damage well screens,
pumps, flow meters, and other components.
In some cases, the well becomes full of sedi-
ment and must be cleaned out. The most fre-
quent method of cleaning is to pull the pump
from the well, circulate clean water down the
well bore through a drop, and flush the sedi-
ment out. If large amounts of sediments are
expected to enter a monitoring well, consider
incorporating a sediment sump, also called a
silt trap or sediment trap, into the monitoring
well construction. The sump consists of a
blank section of pipe placed below the base of
the screen. Its purpose is to provide a catch-
trap for fine sand and silt which bypasses the
filter pack and screen and settles out within
the well. This sediment collects within the
sump rather than within the screen, and there-
fore, does not reduce the functional screened
length of the well and minimizes the need for
periodic cleanouts of the screen. Regardless of
the type of ground-water monitoring well
installed, the well should be protected with a
cap or plug at the upper end to prevent con-
densation, rust, and dirt from entering into the
manhole or protective casing. Inspect the
outer portion of the wells to ensure that they
have not been damaged by trucks or other
unit operations, and to ensure that the cap or
plug are intact.
Inspect and maintain unit covers to ensure
that they are intact. For optimal performance,
covers should be designed to minimize perme-
ability, surface ponding, and the erosion of
cover material. The cover should also prevent
the buildup of liquids within the unit. Consult
the chapter on performing closure and post-
closure care for a more detailed discussion on
maintaining cover systems.
All components of leachate detection and
collection systems must also be maintained
properly. The main components include the
leachate collection pipes, manholes, leachate
collection tanks and accessories, and pumps.
Consider cleaning the leachate pipes once a
year to clear out any organic growth and visual-
ly inspecting the manholes, tanks, and pumps
once a year as leachate can corrode metallic
parts. Annual inspections and necessary repairs
8-4
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Ensuring Long-Term Protection—Operating The Waste Management System
will, therefore, prevent many future emergency
type problems such as leachate overflow from
the tank due to pump failure. Maintain a
record of all repair activities to assess (or
claim) long-term warranties on pumps and
other equipment.
Also, monitor waste liquid levels. An unex-
pected decrease in liquid levels may be an
indication of liner failure. If a surface
impoundment fails, discontinue adding waste
to the impoundment and contain any dis-
charge that has occurred or is occurring.
Repair leaks as soon as possible. If leaks can-
not be stopped, empty the impoundment.
Clean up any released waste and notify the
appropriate state authorities of the failure and
the remedial actions taken.
B. Surface-Water Controls
If a unit has a point source discharge, it
must have a National Pollutant Discharge
Elimination System (NPDES) permit and, in
some states, may require a state discharge
permit. Point source discharges include the
release of leachate from a leachate collection
or onsite treatment system into surface
waters, disposal of solid waste into surface
waters, or release of surface water runoff
(storm water) that is directed by a run-off
control system into surface-waters. Even if
there are no point source discharges, surface-
water controls may be necessary to prevent
pollutants from being discharged or leached
into surface waters, such as lakes and rivers.
Soil erosion and sedimentation controls,
such as ditches, berms, dikes, drains, and silt
fences, should be incorporated into the design
and construction of a unit. Berms or dikes are
often constructed from earthen materials, con-
crete, or other materials designed to be safely
traversed during inspection or monitoring
activities. Vegetation also is often used for ero-
sion control. Trees or other deep rooted vegeta-
tion, however, should not be used near liners
or other structures that could be damaged by
roots. Grassing is often used for soil stabiliza-
tion around surface impoundments. For a more
detailed discussion of storm-water issues, con-
sult the chapter on protecting surface water.
Most, if not all, of these surface-water con-
trols should be inspected regularly and after
each large storm event. Structures should be
maintained as installed and any structural
damage should be repaired as soon as possi-
ble to prevent further damage or erosion, and
any trapped sediments should be removed
and disposed of properly. Vegetative controls
may need watering after planting and during
periods of intense heat and/or lack of rain.
C. Air Controls
Gases, including methane, carbon diox-
ide, and hydrogen, are often produced at
waste management units as byproducts of the
microbial decomposition of solid waste con-
taining organic material. Additionally, volatile
organic compounds (VOCs) may be present
in the waste, and particulate emissions and/or
dust may be generated during unit opera-
tions. Analyze wastes carefully prior to
designing a waste management unit to deter-
mine what airborne emissions are likely to
come from these wastes. If airborne emission
controls are needed in the design of a unit,
maintenance of these controls should be con-
sidered as part of a waste management sys-
tem. For further information on airborne
emission controls, consult the chapter on
protecting air.
Methane is the gas of main concern at
most waste management units because it is
odorless and can cause fires or explosions
that can endanger employees and damage
structures both on and off-site. Hydrogen gas
may also form, and is also explosive, but it
readily reacts with carbon or sulfur to form
8-5
-------
Ensuring Long-Tenn Protection—Operating The Waste Management System
methane or hydrogen sulfide. Hydrogen sul-
fide can be easily identified by its sulfur or
"rotten egg" smell. Methane, if not captured,
will either escape to the atmosphere or
migrate underground. Underground methane
may enter structures, where it may reach
explosive concentrations or displace oxygen,
causing a danger of asphyxiation. Methane in
the soil profile may damage the vegetation on
the surface of the landfill or on the land sur-
rounding the landfill, thereby exposing the
unit to increased erosion. Finally, methane is
a potent "greenhouse" gas that contributes to
global warming.
Methane is explosive when present in the
ranges of 5 to 15 percent by volume in the
air. The 5 percent level is known as the lower
explosive limit (LEL) and 15 percent as the
upper explosive limit (UEL). At levels above
15 percent by volume, methane will not
explode when exposed to a source of igni-
tion. Levels above the UEL remain a concern,
however, as methane will burn at these con-
centrations and can still cause asphyxiation.
In the event that methane gas levels exceed
25 percent of the LEL in facility structures or
other closed spaces, initiate safety measures,
such as evacuating the site and structures. In
such cases, or when the methane level
exceeds 25 percent of the LEL in the soil at a
monitoring point, implement a remediation
plan to decrease gas levels and prevent future
buildup of gases.
Gas control systems generally include
mechanisms designed to control gas migra-
tion and to help vent gas emissions into the
atmosphere. Systems using natural pressure
and convection mechanisms are referred to as
passive gas control systems (see Figure 2).
Examples of passive gas control system ele-
ments include ditches, trenches, vent walls,
perforated pipes surrounded by coarse soil,
synthetic membranes, and high moisture,
fine-grained soil.
Systems using mechanical means to remove
gas from the unit are referred to as active gas
control systems. Figure 3 illustrates an active
gas system. Gas extraction wells are an exam-
ple of active gas control systems. Gas control
systems can also be used as part of corrective
action measures should the concentration of
methane rise to dangerous levels.
Figure 2. Passive Gas Venting System
soil
vent
Source: Robinson, W., ed. 1986. The Solid Waste Handbook: A Practical Guide.
Reprinted by permission of John Wiley & Sons, Inc.
8-6
-------
Ensuring Long-Term Protection—Operating The Waste Management System
Figure 3. Active Gas Venting System
gas monitoring probe
installed in refuse
I
> gas collection line /
1 • > J
I gas
I monitoring
j probe
| installed
in surrounding
ground
Source: Robinson, W., ed. 1986. The Solid Waste Handbook: A Practical Guide.
Reprinted by permission of John Wiley & Sons, Inc.
As with all aspects of a waste contain-
ment system, construction quality assurance
plays a critical role in the success of a gas
management system. For deep wells, the
number, location, and extent of the pipe per-
forations are important. Also, the depth of
the well must be kept safely above the liner
system beneath the waste. For continuous gas
collection layers beneath the barrier layer,
continuity is important for both soils and
geosynthetics.
Knowing the rate of gas generation is
essential to determining the quantity of gas
that can be extracted from the site. Pumping
an individual well at a greater vacuum will
give it a wider zone of influence, which is
acceptable, but obviously there are points of
diminishing marginal returns. Larger suction
pressures influence a larger region but
expend more energy in the pumping.
Pumping at greater vacuum also increases the
potential for drawing in atmospheric air if the
pumping rate is set too high. Significant air
intrusion into the unit may result in elevated
temperatures and even underground fires.
Perform routine checks of gas generation
rates to better ensure that optimal pumping
rates are used.
The performance of gas extraction systems
is affected by the following parameters.
Consider these when designing and operating
gas systems:
• Daily cover, which inhibits free movement
of gas;
• Sludge or liquid wastes, which affect the
ease at which gas will move;
• Shallow depth of unit, which makes it
difficult to extract the gas, because
atmospheric air will be drawn in during
the pumping; and
8-7
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Ensuring Long-Tenn. Protection—Operating The Waste Management System
• Permeability of the final cover, which
affects the ability of atmospheric air to
permeate the wastes in the unit.
With a geomembrane in the final cover
barrier system, uplift pressures will be exert-
ed unless the gas is quickly and efficiently
conveyed to the wells, vents, or collection
trenches. If this is not properly managed,
uplift pressure will either cause bubbles to
occur displacing the coyer soil and appearing
at the surface, or it decreases the normal
stress between the geomembrane and its
underlying material. This problem has led to
slippage of the geomembrane and all overly-
ing materials creating high tensile stresses evi-
denced by folding at the toe of the slope and
tension cracks near the top.
Gas monitoring and extraction systems
require regular maintenance to operate effi-
ciently. As wastes settle over time, pipes may
fail and condensate outlets may become
blocked. Extracted gas is saturated, which
causes moisture to collect within the pipes.
Therefore, the^condensate within the pipes
must be dealt with, otherwise it will affect the
pumping suction pressure. Since the plumb-
ing on the top of the unit is quite involved,
develop and adhere to a gas maintenance
schedule to ensure the efficient operation of
gas systems.
III. Operational
Aspects of a
Waste
Management
System
Consider developing practices to ensure
compliance with applicable laws and regula-
tions, train workers how to handle potential
problems, and to ensure that all necessary
improvements or changes are made to a waste
management system. Proper planning and
implementation of these operating practices
are important elements in the efficient and
protective operation of a unit. This section
identifies and briefly discusses some of the
important operational aspects including devel-
oping an operating plan, performing waste
analyses and inspections, installing daily cov-
ers, placing wastes in a unit, implementing
security and access control measures, provid-
ing employee training, addressing nuisance
concerns, and maintaining important records.
A. Operating Plan
An operating plan should serve as the
primary resource document for operating a
waste management unit. It should include
the technical details necessary for a unit to
operate according to its design throughout
the intended working life. At a landfill, for
example, the operating plan should illus-
trate the chronological sequence for filling
the unit, and it should be detailed enough
to allow the facility manager to know what
to do at any point in the operations phase
of the unit.
An operating plan should consider:
• A daily procedures component;
8-8
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Ensuring Long-Tenn Protection—Operating The Waste Management System
• Lists of current equipment holdings and
of future equipment needs;
• Procedures to inspect for inappropriate
wastes and to respond when their pres-
ence is suspected;
• Procedures for addressing extreme weather
conditions;
• Personnel needs and equipment utiliza-
tion, including backup;
• Procedures to address emergencies, such
as medical crises, fires, and spills;
• Quality control and employee perfor-
mance standards;
• Record keeping protocols; and
• Means of compliance with local, state,
and federal regulations.
Since a unit will likely operate for several
years, it is important that staff periodically
review the operating plan to refresh their
memories and to ensure long-term conformi-
ty with the plan. If modifications to the oper-
ating plan are necessary, the changes and the
date they were made should be noted in the
operating plan. Documented operating proce-
dures can be crucial, especially if questions
arise in the future regarding the adequacy of
site construction and management.
• A key goal of a sound operating plan is to
standardize daily procedures. This part of the
operating plan outlines the day-to-day activi-
ties necessary to place waste, operate environ-
mental controls, and inspect and maintain the
waste management unit in accordance with
its design. Daily procedures should be con-
cise enough to be circulated among all
employees and flexible enough to allow any
adjustments necessary to accommodate
weather variability, changing waste volume,
and other contingencies. Revise and update
daily procedures as needed to ensure the
unit's continued safe operation within the
parameters of the overall operating plan.
B. Waste Analysis
An effective waste management system
relies on knowledge of the wastes being man-
aged and the need to monitor for changes in
waste characteristics. It is imperative that the
chemical and physical composition of the
wastes, and any changes to the wastes, be
understood in order to prevent mixing of
incompatible wastes, ensure proper handling
of wastes, and make the most efficient use of
unit capacity. Familiarity with wastes and
changes in waste composition also helps to
identify potential waste reduction and/or pol-
lution prevention opportunities. The best way
to determine waste characteristics is to per-
form a comprehensive waste analysis on the
materials to be managed. This analysis will
provide the necessary information for proper
waste treatment, storage, or disposal. To
ensure that this information remains accurate,
repeat the analysis whenever there is a change
in the industrial process generating the waste.
For further information, consult the chapter
on characterizing waste.
C. Waste Inspections
The purpose of performing waste inspec-
tions is to identify waste that may be inappro-
priate for the waste management unit, and to
prevent problems and accidents before they
happen. Hazardous wastes, PCBs, liquids (in
landfills and waste piles), and state designat-
ed wastes are prohibited from disposal in
8-9
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Ensuring Long-Tom Protection—Operating The-Waste Management System
units designated solely for industrial nonhaz-
ardous waste. Some states have developed
more stringent screening requirements that
may require a spotter to be present at a unit
to detect unauthorized wastes and to weigh
and record incoming wastes.
As part of a waste management system,
screening procedures need to be implemented
to prevent inappropriate wastes from entering
a unit. Such procedures typically call for
Inspect waste to ensure that hazardous
waste is not placed in a unit.
screening waste as it enters a unit. Ideally, all
wastes entering a unit should be screened, but
this is not always practical. A decision may be
made, therefore, to screen a percentage of
incoming waste. It may be practical to use spot
inspections, such as checking random loads of
waste on a random day>each week or every
incoming load on one random day each
month. Base the frequency of random inspec-
tions on the type and quantity of wastes
expected to be received, the accuracy and con-
fidence desired, and any state inspection
requirements. Inspections need to be per-
formed prior to placement of wastes in a unit.
Training employees to recognize inappro-
priate wastes during routine operations
increases the chances that inappropriate
waste arriving on non-inspection days will be
detected. Some indications of inappropriate
wastes are color, texture, or odor different
from those of the waste a unit normally
receives. Laboratory testing can be per-
formed to identify different wastes.
A waste management system needs to
include procedures to address suspected
inappropriate waste. The procedures to
implement when inappropriate wastes are
found should include the following.
• Segregate the suspicious wastes;
• Use appropriate personal protective
equipment;
• Contact the part of the industrial facility
that generated the waste to find out more
about it;
• Contact laboratory support to analyze the
waste, if required;
• Call the appropriate state, tribal or federal
agencies; and
• Notify a response agency, if necessary.
I
Should liquids be restricted from
being placed in some units?
Bulk or containerized liquids should not
be placed in landfills or waste piles, as liquids
increase the potential for leachate generation.
Liquid waste includes any waste material
determined to contain free liquids as defined
by Method 9095 (also known as the paint fil-
ter test) in EPA's Test Methods for Evaluating
Solid Waste, Physical/Chemical Methods (SW-
846). Sludges are a common waste that may
contain significant quantities of liquids.
Consider methods such as drying beds to
dewater sludges prior to placement in land-
fills and waste piles.
8-10
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Ensuring Long-Term Protection—Operating The Waste Management System
D. Daily Cover
It may be necessary to apply a daily cover
to operating landfills and waste piles.
Covering the waste helps control nuisance
factors, such as the escape of odors, dust, and
airborne emissions, and can control the pop-
ulation of disease vectors. Some cover materi-
als, due to their ability to hold moisture, may
reduce the infiltration of rain water, decreas-
ing the generation of leachate and the poten-
tial for surface-water and ground-water cont-
amination.
How is daily cover applied?
Covers most often consist of earthen mate-
rial, although there are several alternative
daily covers being used in the industry today,
including coproducts, foam, geotextiles, and
plastic sheets or tarps. Examples of coprod-
ucts that have been used as daily cover
include granular wastes, automobile shredder
fluff, foundry sand, dewatered sludges, and
synthetic soils. When using coproduct covers
that may themselves contain contaminants,
ensure that run-off is either diverted before it
contacts the cover material or captured and
handled appropriately after contacting it.
Granular wastes used as daily cover should
be low in fine-grained particles to avoid
waste being transported by wind. Before
using alternative covers, especially coprod-
ucts, consult the state to determine what, if
any, regulations apply.
Daily cover should be applied after the
waste has been placed, spread, and compact-
ed. Cover frequency, if not daily, is most often
determined by the type of industrial waste
disposed of at the landfill or waste pile. More
frequent application of earthen material may
be required if undesirable conditions persist.
A typical daily soil cover thickness is 6 inch-
es, but different thicknesses may be sufficient.
When using earthen cover, avoid soils with
high clay content. Clay, due to its low perme-
ability, can block vertical movement of water
and channel it horizontally through the land-
fill or waste pile.
Using alternative daily cover materials may
save valuable space in a waste management
unit. Some types of commercially available
daily cover materials include foam that usual-
ly is sprayed on the working face at the end
of the day; and geosynthetic products, such
as a tarp or fabric panel that is applied at the
end of the working day and removed at the
beginning of the following working day.
Some of these materials require specially
designed application equipment, while others
use equipment generally available at most
units. Criteria to consider when selecting an
alternative daily cover material include avail-
ability and suitability of the material, precipi-
tation, chemical compatibility with waste,
equipment requirements, and cost.
E. Placing Wastes
To protect the integrity of liner systems,
the waste management system should pre-
scribe proper waste placement practices. The
primary physical compatibility issue is punc-
ture of the liner by sharp objects in the waste.
Ensure that the liner is protected from items
angular and sharp enough to puncture it.
Similarly, facility employees should be
instructed to keep heavy equipment off the
liner. Another physical compatibility issue is
keeping fine-grained waste materials away
from drainage layers that could be clogged by
such materials.
To avoid differential settlement, focus on
how the waste is placed on the liner material
or on the protective layer above the liner.
8-11
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Ensuring Long-Temx Protection—Operating The Waste Management System
Uneven placement of waste, or uneven com-
paction can result in differential settlement of
succeeding waste layers or of final cover.
Differential settlement, in turn, can lead to
ponding and infiltration of water and damage
to liners or leachate collection systems. In
extreme cases, failure of waste slopes can
occur. To avoid these problems, ensure that
waste is sufficiently stabilized and, if possible,
compacted.
To protect liner integrity in lined surface
impoundments, consider placing an erosion
guard or a concrete pad on the liner at the
point where waste discharges into the unit.
Otherwise, pressure from the waste hitting
the liner may accelerate liner deterioration in
that area. Inlet pipes can also be arranged so
that liquid waste being discharged into the
unit is diffused upward or to the side.
Although inlet pipes can enter the surface
impoundment above the water level, the
point of discharge should be submerged to
avoid generating odor and disturbing the cir-
culation of stratified ponds. Discharging liq-
uid waste straight into the unit without diffu-
sion is not recommended as this can disrupt
the intended treatment.
If significant amounts of sludge accumu-
late on the bottom of an impoundment, it
may be necessary to dredge the impound-
ment and dispose of the sludge periodically.
There are two main concerns regarding
sludge management: protecting the liner
while cleaning out sludge from the impound-
ment and properly disposing of any removed
sludge. During dredging, heavy equipment
can damage the liner.'Avoid this by selecting
equipment and methods that protect the liner
during sludge removal. Further, any sludge
removed should be evaluated and managed
in an appropriate manner, based on its chem-
ical properties.
F. Climate Considerations
Waste management operations may be
affected by weather conditions, especially
rain, snow, or wind. Rainy or snowy weather
can create a variety of problems, such as
inhibited vehicle access and difficulty in
spreading and compacting waste. To combat
these difficulties, consider altering drainage
patterns, maintaining storm-water controls,
maintaining all-weather access roads (if
appropriate), or designating a wet-weather
disposal area.
Extremely cold conditions may prevent
efficient excavation of soil from a borrow pit
and can also inhibit the spreading and com-
paction of soil cover on, the waste. Freezing
temperatures can also inflict excessive wear
on equipment. To combat these problems,
use coarse-textured soil during winter opera-
tions, stockpile cover soil for winter use, and
protect cover soil with leaves, plastics, or
other insulating materials.
Consider using special inclement weather
disposal areas during extreme wet and windy
weather. In wet weather, placing waste in a
part of the unit near the entrance reduces the
likelihood of trucks causing ruts on site road-
ways or being stranded in mud. Under windy
conditions, waste may need to be wetted or
placed in downwind areas of a unit to reduce
blowing waste or particulates.
G. Security Measures,
Access Control, and
Traffic Management
To prevent injury to members of the pub-
lic, consider implementing security and
access control measures to block unautho-
rized entry to a unit. These measures may
also help to prevent scavenging, vandalism,
and illegal dumping of unauthorized wastes.
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Ensuring Long-Term Protection—Operating The Waste Management System
Examples of access control measures include
fences, locked gates, security guards, surveil-
lance systems, or natural barriers, such as,
berms, trees, hedges, ditches, and embank-
ments. The site perimeter should be clearly
marked or fenced. Additionally, consider post-
ing signs that warn of restricted access and alert
the public to the potential for harm associated
with heavy equipment operations.
How can onsite traffic best be
managed?
Even though access to the unit is limited,
it is necessary to provide clear transportation
routes for emergency response equipment to
access the waste management unit. Traffic
management is often overlooked as part of
waste management unit operations. Proper
traffic routing can help a unit operate more
smoothly and prevent injuries and deter
intruders. Access roads should be designed
and built to be safe and efficient, without
blind spots or unmarked intersections. They
should also be located to provide long-term
service without requiring relocation. Posting
clear directional signs can help direct traffic
and reduce the potential for vehicle acci-
dents. Providing all-weather access roads (if
appropriate) and temporary storage areas can
improve waste transport to and from a unit
and allow equipment to move about more
freely. In addition, consider imposing onsite
speed limits or constructing speed bumps.
Access roads should be maintained proper-
ly at all times. Adequate drainage of road
beds is essential for proper operation of a
unit. Heavy, loaded vehicles traveling to and
from a unit deteriorate the roads on which
they travel. Equipment without rubber tires
should not be allowed on the paved stretches
of roads as they may damage the roads.
Sufficient funds should be allocated up front
for the maintenance of access roads.
What are some other prudent
safety measures?
There are a number of considerations asso-
ciated with ground-water monitoring wells.
The tops of monitoring wells should be clear-
ly marked and accessible. In traffic areas,
posts and/or bumper guards around monitor-
ing wells may help protect aboveground
installations from damage. Posts and/or
bumper guards come in various sizes and
strengths and are typically constructed for
high visibility and trimmed with reflective
tape or highly visible paint containing reflec-
tive material. Proper labeling of monitoring
wells is important for several reasons.
Monitoring wells should be distinguished
from underground storage tank fill lines, for
example. Also, different monitoring wells
should be distinguished from each other.
Monitoring wells, therefore, should be
labeled on immovable parts of the well.
H. Providing Employee
Training
One of the most important aspects of a
waste management system is employee train-
ing. Employees should be trained before their
initial assignment, upon changing assignments,
and any time a new health or safety hazard is
introduced into the work area. A good training
program uses concrete examples to improve
and maintain employee skill, safety, and team-
work. Training can be provided by in-house
Classroom training helps familiarize
employees with operating procedures.
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Ensuring Long-Term Protection—Operating The Waste Management System
trainers, trade associations, or specialized con-
sultants. In some states, proactive safety and
training programs are required by law.
What types of training can be
provided for employees?
The following categories of training pro-
grams may be applicable to employees:
• Manager and supervisor training;
• Equipment operator training and heavy
equipment maintenance;
Sample Manager and Supervisor
Training Agenda
• Introduction
• Unit basics:
—Siting
—Waste containment
—Daily operations
Owning and operating machines
Machine types
Equipment maintenance
Maximizing airspace
Labor management
Production analysis
Application of production rate data
Budgets and data tracking:
—Operating budget
—Cover soil budget
—Airspace budget
• Waste handling techniques
• Waste management techniques
• Cover soil placement
• Safety issues and safety meetings
• Record keeping
• Emergency response plan
• State requirements for operation
Bolton, N. 1995, The Handbook of Landfill
Operations: A Practical Guide for Landfill
Engineers, Owners, and Operators. (ISBN 0-
9646956-0-5Q. Reprinted by permission.
• Laborer training; and
• Safety training for all employees.
Safety is a primary concern because waste
management operations can present a variety
of risks to workers. In addition, employee
right-to-know laws require employers to pro-
vide training and information about safety
issues pertinent to a given occupation.
Furthermore, accidents can be expensive,
with hidden costs often amounting to several
times the apparent costs. Accidents at waste
management units can include injury from
explosions or fire, inhalation of contaminants
and dust, asphyxiation from poorly vented
leachate collection system manholes or tanks,
falls from vehicles, injury associated with
operating heavy earth-moving equipment,
exposure to extreme cold or heat, and onsite
traffic accidents.
To minimize risks to workers, provide an
ongoing safety training program to ensure all
staff are properly and regularly trained on
safety issues. A safety training program
should be consistent with the requirements
specified by the U.S. Occupational Safety and
Health Administration (OSHA) and include
initial training and frequent refresher sessions
on at least the following topics:
• Waste management operations;
• Hazardous waste identification;
• Monitoring equipment operations;
• Emergency shut-off procedures;
• Overview of safety, health, and other
hazards present at the site;
• Symptoms and signs of overexposure_to
hazards;
• Proper lifting methods, material handling
procedures, equipment operation, and
safe driving practices;
• Emergency response topics, such as spill
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Ensuring Long-Tenn Protection—Operating The Waste Management System
response, fire suppression, hazard analysis,
and location and operation of emergency
equipment; and
• Requirements for personal protective
gear, such as hard hats, gloves, goggles,
safety shoes, and high-visibility vests.
Weave a common thread of teamwork into
every training program. Breaks in communi-
cation between site engineers and field opera-
tions personnel can occur. Bridging this gap
is an important step toward building an effec-
tive unit team that can work together.
Consider periodic special training to update
employees on new equipment and technolo-
gies, to improve and broaden their range of
job-related skills, and to keep them fresh on
the basics. Training can also include such
peripheral topics as liability concerns, first
Sample laborer Training Agenda
• Introduction
• Unit basics:
—Siting ' .''•
—Waste containment
—Daily operations
Traffic management and safety :
Interacting \vith the public
Load segregation and placement
Hazardous material identification
procedure .'-.,-," .' x-
Unit equipment types and applications
Cover operations
Equipment maintenance
Unit safety
—Heavy equipment safety
—Traffic safety . - .'.-•'.
—Personal protective equipment
• Emergency response plans
Bolton, N. 1995, The Handbook of Landfill
Operations: A Practical Guide for Landfill
Engineers, Owners, and Operators. (ISBN 0- '
9646956-0-X). Reprinted by permission.
aid, avoidance of substance abuse, and stress
management.
How should training programs
be conducted?
Keep records of the type and amount of
training provided to employees, and obtain
documentation (employee signatures) whenev-
er training is given. Consider establishing reg-
ular (at least monthly) safety meetings, during
which specific topics can be addressed and
employees can voice concerns, ask questions,
and present ideas. Keep meetings short and to
the point, and steer discussion toward topics
Equipment Operator Training Agenda
• Introduction '
• Unit basics: . - ...
—Siting:"- " . • , - , ,
. ,V —Wastecontainment
—Daily-operations:
• Heavy equipment types and applications:
—Scraper, dozer, arid compactor
operations .,' .";-.'-',...
—Support equipment
—Fluids
. —Fueling,maintenance arid its
hazards, and fuel spill prevention^
• Coveroperations:
—Types of cover soil ,';.
, ; —Placement of cover soil
• Drainage control
• Surveying and staking ;
• Unit safety: .- .-.' :: .
-—Emergency response plans
—Safe operating techniques
• Owning and operating costs
Bolton, N;' 1995, The Handbook of Landfill,
Operations: A Practical Guide for Landfill
Engineers, Owners, and Operators. (ISBN 0-
9646956-0-X). Reprinted by permission.
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Ensuring Long-Term Protection—Operating The Waste Management System
that are applicable to those-employees present.
In addition, do not waste time talking about
issues not applicable to a site. If a site experi-
ences extreme weather conditions, develop
safety meeting topics that address weather-
related safety. Many safety-related videos are
available and can add variety to meetings.
Closely monitor worker accident and injury
reports to try to identify conditions that war-
rant corrective or preventive measures. In
addition, it is wise to document all safety
meetings. Assistance in establishing a safety
program is available from insurance compa-
nies with worker's compensation programs,
the National Safety Council, safety consul-
tants, and federal and state government safety
organizations. The overall cost of an aggres-
sive, preventive safety program is almost cer-
tain to be offset by the savings from a decrease
in lost work time and injuries.
I. Emergency Response
Plan and Procedures
There are three major types of waste man-
agement emergencies: accidents, spills, and
fires/explosions. A waste management system
should include emergency response plans for
each of these-scenarios that considers not only
the waste management unit but also all sur-
rounding facility areas. The plans should be
reviewed and revised periodically to keep the
procedures fresh in employees' minds and to
reflect any changes in such items as the unit
operating procedures, facility operations, phys-
ical/chemical changes in the wastes, generated
volumes, addition or replacement of emer-
gency equipment, and personnel changes. If an
emergency does arise, or if hazardous waste is
inadvertently disposed of in a unit, notify
appropriate agencies, adjacent land owners,
and emergency response personnel, if needed.
After emergency conditions have been cleared,
review the waste management system and
revise it, if necessary, to prevent similar
mishaps in the future.
How should an appropriate
emergency response plan be
developed?
An emergency response plan needs to con-
sider the following:
• Description of types ;of emergencies that
would necessitate a response action;
• Names, roles, and duties of primary and
alternate emergency coordinators;
• Spill notification procedures;
• Who should be notified;
• Fire department or emergency response
telephone number;
• Hospital telephone number;
• Primary and secondary emergency
staging areas;
• Location-of first aid supplies;
• Designation and training of several first
aid administrators;
• Location of and operating procedures for
all fire control, spill control, and
decontamination equipment;
• Location of hoses, sprinklers, or water
spray systems and adequate water
supplies;
• Description and listing of emergency
response equipment;
• Maintenance and testing log of emer-
gency equipment;
• Plans to familiarize local authorities, local
emergency response organizations, and
neighbors with the characteristics of the
unit and appropriate and inappropriate
responses to various emergency situations;
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Ensuring Long-Term Protection—Operating The Waste Management System
• Information on state emergency response
teams, response contractors, and
equipment suppliers;
• Properties of the waste being handled at
the unit, and types of injuries that could
result from fires, explosions, releases, or
other mishaps;
• An evacuation plan for unit personnel (if
applicable); and
• Requirements for prominent posting of
the above information.
The emergency plan should instruct all
employees what to do if an emergency arises,
and all employees should be familiar with the
plan and their responsibilities under it. In order
to ensure that everyone knows what to do in
an emergency, conduct periodic drills. These
practice responses could be planned ahead of
time or they could be unannounced. Either
way, the drills are treated as real emergencies
and serve to hone the skills of the employees
who may have to respond to actual emergen-
cies. The key to responding effectively to an
emergency is knowing in advance what to do.
Communication is vital during an emer-
gency and should be an inherent component
of any emergency response plan. Two-way
radios and bullhorns can prove invaluable in
the event of an emergency, and an alarm sys-
tem can let employees know that an emer-
gency situation is at hand. Designate one or
more employees who will not be essential to
the emergency response to handle public
affairs during a major emergency. These
employees should work with the press to
ensure that the public receives an accurate
account of the emergency.
J. Record Keeping
Record keeping is a vital part of cost-effec-
tive, efficient waste management unit opera-
tions. Records should be maintained for an
appropriate period of time, but it is a good
idea to keep a set of core records indefinitely.
Some facilities have instituted policies that
records are to be maintained for up to 30
years while other facilities maintain records
for only 3 years. Some states have record
keeping requirements for certain waste man-
agement units and associated practices.
Check with state authorities to determine
what, if any, record keeping is required by
law and to determine how long records
should be kept.
Besides being required by some states,
records help evaluate and optimize unit per-
formance. Over time, these records can serve
as a valuable almanac of activities, as well as a
source of cost information to help fine tune
future expenditures and operating budgets.
Data on waste volume, for example, can allow
a prediction of remaining site life, any special
equipment that may be needed, and personnel
requirements. Furthermore, if a facility is ever
involved in litigation, accurate, dated records
can be invaluable in establishing a case.
What type of records should be
kept?
Operational records that should be main-
tained include the following, as appropriate:
• Waste analysis results;
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Ensuring Long-Term Protection—Operating The Waste Management System
• liner compatibility testing;
• Waste volume;
• Location of waste placement, including a
map;
• Depth of waste below the final cover
surface;
• Cover material used and available;
• Frequency of waste application;
• Equipment operation and maintenance
statistics;
• Environmental monitoring data and
results;
• Inspection reports, including
photographs;
• Design documents, including drawings
and certifications;
• Cost estimates and other financial data;
• Plans for unit closure and post-closure
care;
• Information on financial assurance
mechanisms;
• Daily log of activities; and
• Calendar of events.
Health and safety records that should be
maintained include the following:
• Personal information and work history
for each employee, including health
information such as illness reports;
• Accident records;
• Work environmental records; and
• Occupational safety records, including
safety training and safety surveys.
K. Addressing Nuisance
Concerns
Minimizing nuisances, such as noise, odor,
and disease vectors, is of great importance for
the health of personnel working in the indus-
trial facility and of neighbors that live or
work near a unit. This section describes
many of the nuisance concerns typical of
waste management units and offers measures
to address them. Measures, besides those list-
ed can be used to achieve the same objective.
How can noises be minimized?
Noise resulting from the operation of
heavy equipment may be a concern for waste
management units located near residential
areas. Noise may also disrupt animal habitats
and behavior. In addition, workers' hearing
and stress levels can be adversely affected by
long-term exposure to noise. At waste man-
agement units where noise is a concern, lim-
iting hours of operation may reduce potential
problems. Design access routes to minimize
the impact of site traffic noise on nearby
neighborhoods. Equipment should also be
maintained to minimize unnecessary noise,
and affected workers should wear ear protec-
tion (plugs or muffs). Berms, wind breaks, or
other barriers can be erected to help mute
sounds. OSHA has-established standards for
occupational exposure to noise (see 29 CFR
§1910.95).
How can odor be minimized?
Increased urbanization has led to industri-
al facilities being situated in close proximity
to residential areas and commercial develop-
ments. This has resulted in numerous com-
plaints about odors from industrial waste
management units and industrial processes
such as poultry processing, slaughtering and
rendering, tanning, ancl manufacture of
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Ensuring Long-Tenn Protection—Operating The Waste Management System
volatile organics. Some of the major sources
of odors are hydrogen sulfide and organic
compounds generated by anaerobic decom-
position. The latter may include mercaptans,
indole, skatole, amines, and fatty acids. Odor
may be a concern at a unit, depending on
proximity to neighbors and the nature of the
wastes being managed. In addition to causing
complaints, odors may be a sign of toxic or
irritating gases or anaerobic conditions in a
unit that could have adverse health effects or
environmental impacts. Plan to be proactive
in minimizing odors, and establish proce-
dures to respond to citizen complaints about
odor problems and to correct the problems.
Odors may be seasonal in nature and, there-
fore, can often be anticipated. Some odors at
landfills, waste piles, and land application units
arise either from waste being unloaded or from
improperly covered in-place waste. If odor
from waste being unloaded becomes a prob-
lem, it may be necessary to place these loads in
a portion of the unit where they can be imme-
diately covered with soil. At land application
units, quick incorporation or injection of waste
can help prevent odor. It also may be necessary
to establish a system whereby unit personnel
are notified when odorous wastes are coming
to the unit to allow them to prepare according-
ly Odors from in-place waste can effectively be
minimized by maintaining the integrity of
cover material over everything but the current-
ly active face. Proper waste compaction also
helps to control odors. Consider implementing
gas controls if odors are associated with gases
generated from a unit.
If odors emanate from surface impound-
ments, there are several options available for
control, including biological and chemical
treatment. The type of treatment for an
impoundment should be determined on a
site-specific basis, taking into account the
chemistry of the waste.
Practices to control odor are especially
important at land application units. If land
application is used, apply waste at appropri-
ate rates for site conditions, and design and
locate waste storage facilities to minimize
odor problems. Make it a priority to mini-
mize potential odors by applying wastes as
soon as possible after delivery and incorpo-
rating wastes into the soil as soon as possible
after application. Cleaning trucks, tanks, and
other equipment daily (or more frequently, if
necessary) may also help reduce odor. Avoid
applying waste when soils are wet or frozen
or when other soil or slope conditions would
cause ponding or poor drainage.
Other methods of controlling odors
include:
• Covering or enclosing the unit;
• Adding chemicals such as chlorine, lime,
and ferric chloride to reduce bacterial
activity and oxidize many products of
anaerobic decomposition;
• Using biofilters;
• Applying a deep soil cover, whose upper
layers consist of silty soils or soils con-
taining a large percentage of carbon or
humic material;
• Applying a layer of relatively imperme-
able soil, so as to reduce gas generation
rates by reducing the amount of rainfall
water percolating into the waste;
• Covering leachate collection areas; and
• Restoring landfill surface covers when
subsidence and cracks occur.
Choosing a method for controlling odors
requires a comprehensive understanding of
wastes and how they react under certain cir-
cumstances. Consult with state agencies to
determine the most effective odor control
method for the wastes in question.
In addition to these steps to control odor
generation, consider steps to manage those
8-19
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Ensuring Long-Tenn Protection—Operating The Waste Management System
odors that are generated. When designing a
waste management unit, consider installing
barriers such as walls, berms, embankments,
and dense plantings of trees set at right
angles to the flow of cold, odorous night-
time air. These measures may help to impede
the odor and dilute it through mixture with
higher layers of fresh air. Alternatively, con-
sider placing an impermeable fence or wall
on top of a berrn or embankment, on its
downwind side. This will increase odor
plume height, and odors will be diluted on
the steep downslope side of the barrier as a
result of turbulent mixing of air layers as the
cold air flows over it. Try to locate such bar-
riers as close to the unit as possible.
Another design suggestion is to plant fast-
growing evergreen trees, which have good
windbreak properties, in buffer-zones around
a unit. In addition to dispersing odors, dense
plantings of evergreen trees will also help to
protect the unit itself from strong winds,
reducing the possibility of windblown soil
erosion.
How can disease vectors be
controlled?
Disease vectors are animals or insects,
such as rodents, flies, birds, and mosquitos,
that can transmit disease to humans.
Burrowing pests, such as gophers, moles, and
groundhogs, may not only carry disease but
can also damage vital unit structures, such as
liners, final cover materials, drainage ditches,
and sedimentation ponds. As a result, these
animals can create costly problems.
Putrescible wastes, along with standing
water, can provide an ideal food source and
potential breeding medium for disease vec-
tors. If putrescible wastes are being managed,
consider the following methods to control
disease vectors:
• Apply adequate daily cover. This simple
action is often all that is needed to con-
trol many disease vectors;
• Reduce the size of the working face at a
landfill so that less waste is exposed;
• Make sure the unit is properly drained,
reducing the amount of standing water
that acts as a breeding medium for
insects;
• Use predator decoys and acoustic con-
trols to scare away birds; and
• As a last resort, or when the application
of cover material is impractical, consider
using repellents, insecticides, rodenti-
cides, or pest reproductive control. Care
must be taken to make sure that pesti-
cides are used only in accordance with
specified uses and application methods.
Follow the instructions carefully when
using these products. Trapping animals may
also be considered, but trapping alone rarely
eliminates the problem.
If land applying wastes, subsurface injec-
tion and prompt incorporation of waste can
help control vectors. Both of these methods
work by using the soil as a barrier between
the waste and vectors. If a waste storage facil-
ity exists, these may attract vectors as well
and should not be overlooked in the imple-
mentation of vector control. If vector prob-
lems arise at a site, take steps to address
them promptly.
8-20
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Ensuring Long-Term Protection—Operating The Waste Management System
General Waste Management System Action Items
a
a
a
a
a
a
a
a
a
a
a
a
a
Develop a waste management system identifying the standard procedures
necessary for a unit to operate according to its design throughout the intended
working life.
Provide proper maintenance and operation of ground-water, surface-water, and
air controls.
Develop daily procedures to place waste, operate environmental controls, and
inspect and maintain the unit.
Review at a regular interval, such as annually, whether the waste management
system needs to be updated.
Develop a waste analysis procedure to ensure an understanding of the physical
and chemical composition of the waste to be managed.
Develop regular schedules for waste screening and for unit inspections.
If daily cover is recommended, select an appropriate daily cover and establish
processes for placing and covering waste.
Consider how operations may be affected by climate conditions.
Implement security measures to prevent unauthorized entry.
Provide personnel with proper training.
Establish emergency response procedures and familiarize employees with
emergency equipment.
Develop procedures for maintaining records.
Establish nuisance controls to minimize dust, noise, odor, and disease vectors.
8-21
-------
Ensuring Long-Term Protection—Operating The Waste Management System
Resources
ASTM. 1993. Standard practice for maintaining health and safety records at solid waste processing facilities.
E 1076-85.
Bagchi, A. 1994. Design, construction, and monitoring of landfills. John Wiley & Sons Inc.
Bokon, N. 1995. The handbook of landfill operations: a practical guide for landfill engineers, owners, and
operators. Blue Ridge Solid Waste Consulting.
Robinson, W. 1986. The solid waste handbook: A practical guide. John Wiley & Sons Inc.
Taylor, M and JoyceJ. 1994. Warning: Signs point to risky landfill business. World Wastes. December.
U.S. EPA. 1997. ISO 14000 Resource Directory. EPA625-R-97-003.
U.S. EPA. 1995. Decision-Maker's guide to solid waste management, second edition. EPA530-R-95-023.
U.S. EPA. 1995. State requirements for industrial nonhazardous waste management facilities.
U.S. EPA. 1993. Project Summary: The use of alternative materials for daily cover at municipal solid waste
landfills. EPA600-SR-93-172.
U.S. EPA. 1993. Solid waste disposal facility criteria: Technical manual. EPA530-R-93-017.
U.S. EPA. 1992. Facility pollution prevention guide. EPA600-R-92-088.
U.S. EPA. 1991. Technical resource document: Design, construction, and operation of hazardous and non-
hazardous waste surface impoundments. EPA530-SW-91-054.
U.S. EPA. 1988. RCRA inspection manual. OSWER Directive 9938.2A.
U.S. EPA. 1988. Subtitle D of RCRA, "Criteria for Municipal Solid Waste Landfills" (40 CFR Part 258),
Operating Criteria (Subpart C). Draft/Background document.
8-22
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Part V
Ensuring Long-Term Protection
Chapter 9
Monitoring Performance
-------
Contents
I. Ground-Water Monitoring 9~2
A.Hydrogeological Characterization 9'2
B. Basics of Ground-Water Monitoring 9'4
1. Monitoring Methods 9'4
2. Number of Wells 9'6
3. Lateral and Vertical Placement of Wells 9~7
4. Monitor Well Design, Installation, and Development 9~8
5. Duration of Frequency of Monitoring 9-12
6. Sampling Parameters 9'13
C. Sampling and Analytical Protocols and Quality Assurance and Quality Control 9-15
1. Data Quality Objectives 9'16
2. Sample Collection..... 9'16
3. Sample Preservation and Handling • 9~17
4. Quality Assurance and Quality Control 9'17
5. Analytical Protocols -9-18
D, Analysis of Monitoring Data, Contingency Planning, and Assessment Monitoring .9-18
1. Statistical Approaches 9"18
2. Contingency Planning 9'19
3. Assessment Monitoring 9"19
E. Potential Modifications to a Basic Ground-Water Monitoring Program 9-20
1. Duration and Frequency of Monitoring 9-21
2. Sampling Parameters 9"21
3. Vadose Zone Monitoring 9"2-'-
II. Surface-Water Monitoring 9'26
III. Soil Monitoring 9"27
IV. Air Monitoring • 9"32
Monitoring Action Items 9"33
Q T=T
Resources y~~JJ
-------
Contents
Tables:
Table 1: Factors Affecting Number of Wells Per Location 9.9
Table 2: Potential Parameters for Basic Groundwater Monitoring 9-14
Table 3: Factors Affecting Number of Wells Per Location 9-15
Table 4: Comparison of Manual and Automatic Sampling Techniques 9-28
Figures:
Figure 1: Cross-Section of a Generic Monitoring Well 9.5
Figure 2: Major Methods for In-Situ Monitoring of Soil Moisture or Matrix Potential 9-23
Figure 3: Example Methods for Collecting Soil-Pore Samples 9-24
Figure 4: Soil Gas Sampling System 9-25
-------
-------
Ensuring Long-term Protection—Monitoring Perft
ormance
Monitoring Performance
Carefully designed and implemented monitoring programs are
essential to evaluate whether a unit meets performance objectives
and whether there are releases and impacts on the surrounding
environment that need to be corrected. Effective monitoring pro-
grams protect the environment, improve unit performance and help
reduce long-term costs and liabilities associated with industrial
waste management.
Monitoring the performance of
a waste management unit is a
very important pan of a
comprehensive waste man-
agement system. A properly
implemented monitoring program provides
an indication of whether a waste management
This chapter will, help address the
following questions:
* What site charaaerizations need to be. ,
performed to develop an effective monitor-
ing program?
• What are the basic elements of a moni-
toring program?
• How should sampling and analytical pro-
tocols be used in a monitoring program?
* What procedures should be used to eval-
uate monitoring data? ;
• What elements of. the basic monitorMg
program can be modified to address.site '-•'
conditions?
unit is functioning in accordance with its
design, and detects any changes in the quality
of the environment caused by the unit. The
detection information obtained from a moni-
toring program can be used to ensure the
proper types of wastes are being managed in
the unit, discover and repair any damaged
area(s) of the unit, or determine if an alterna-
tive management approach may be appropri-
ate. By implementing a monitoring program,
facility managers will be able to identify prob-
lems or releases in a timely fashion, and take
the appropriate measures to limit contamina-
tion. Continued detection of contamination
in the environment may require the imple-
mentation of more aggressive corrective
action measures to remediate releases.
This chapter highlights issues associated
with establishing a ground-water monitoring
program because most industrial waste man-
agement units need to have a ground-water
monitoring program. The chapter also pro-
vides a brief discussion of air, surface water,
and soil monitoring that may be applicable to
some units managing industrial waste. Consult
with qualified professionals, such as engineers
and ground-water specialists1, for technical
'For the purpose of this chapter, a qualified "ground-water specialist" refers to a scientist or engineer who
has received a baccalaureate or post-graduate degree in the natural sciences or engineering and has suffi-
cient training and experience in ground-water hydrology and related fields as may be demonstrated by
state registration, professional certifications, or completion of accredited university programs that enable
that individual to make sound professional judgements regarding ground-water monitoring, contaminant
fate and transport, and corrective action.
9-1
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Ensuring Long-Tenn Protection—Monitoring Performance
assistance in making decisions about the
design and operation of a ground-water moni-
toring program. In addition
when questions arise concerning soil, air, or
surface-water monitoring, consult specialists in
these areas as each media requires different
expertise,
I. Ground-Water
Monitoring
A. Hydrogeological
Characterization
An accurate hydrogeological characteriza-
tion is the essential foundation of an effective
ground-water monitoring system.
Hydrogeologic conditions determine ground-
water flow and influence contaminant trans-
port. It is important to thoroughly under-
stand the ground-water flow beneath a site to
decide on the complexity and location of a
ground-water monitoring system that will
provide representative background and
downgradient water measurements.
The goal of a hydrogeological characteriza-
tion is to acquire site-specific data to enable
the development of an appropriate ground-
water monitoring program. The site-specific
data that should be developed includes:
• The lateral and vertical extent of the
uppermost aquifer;
• The lateral and vertical extent of die
upper and lower confining units/layers;
• The geology at the waste management
unit's site, such as stratigraphy, lithology,
and structural setting;
• The chemical properties of the upper-
most aquifer and its confining layers rela-
tive to local ground-water chemistry and
wastes managed at the unit; and
Why is it im|xjrtant to use a qualified pro-
fessional?
• Site characterizations can be extremely
complex.
• Incorrect or incomplete characteriza-
tions could result in inaccurate detec-
tion of contamination in the ground
water due to improper placement of
ground-water monitoring wells and
may cost a significant amount of
money. In addition incorrect or
incomplete characterizations could
Tesult in the installation of unneces-
sary monitoring wells also costing a
significant amount of money.
• Always use a qualified professional to
conduct site cnaraaerizations. Check
to see if the professional has sufficient
training and experience in ground-
water hydrology and related fields as
may be demonstrated by state registra-
tion, professional certificationsv or
completion of accredited university
programs. These professionals should
be experienced at analyzing ground-
water flow and. contaminant fate and
transport. Ensure that these profes-
sionals are familiar with the contami-
nants in the waste and thoroughly
Ground-water flow, including
- The vertical and horizontal directions of
ground-water flow in the uppermost
aquifer,
- The vertical and horizontal components
of the hydraulic gradient in the upper
most and any hydraulically connected
aquifer,
- The hydraulic conductivities of the
materials that comprise the upper-most
aquifer and its confining units/layers, and
9-2
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Ensuring Long-Tenn Protection—Monitoring Performance
- The average linear horizontal velocity of
ground-water flow in the uppermost
aquifer.
To perform a hydrogeological characteriza-
tion and develop an understanding of a site's
hydrogeology, a number of investigations can
be used:
• Existing information. Investigate the
waste management history of the site,
such as documented records describing
wastes managed on site and releases.
Some hydrogeological information may
also have been developed in the past. It
may be useful to conduct literature reviews
for reports of research performed in the
area of the unit and examine federal and
state geological and environmental files/
reports related to the site or to the region
where the site is to be located.
• Site geology. A geologic unit is typically
considered to be any distinct or definable
native rock or soil stratum. Characterize
thickness, stratigraphy, lithology, and
hydraulic characteristics of saturated and
unsaturated geologic units and fill materi-
als overlying the uppermost aquifer,
materials of the uppermost aquifer, and
materials of the lower confining unit of
the uppermost aquifer using soil borings
or geophysical methods. Conventional
soil borings are typically used to charac-
terize onsite soils through direct sam-
pling. Geophysical equipment, such as
ground-penetrating radar, electromagnet-
ic detection equipment, and electrical
resistivity arrays, provides a non-invasive
measurement of physical, electrical, or
geochemical properties of the site. Under-
standing the different strata will help locate
the appropriate ground-water monitoring
well locations and screen depths.
• Ground-water flow beneath the site.
Across the United States, ground-water
flow velocities range from several feet to
over 2,000 feet per year. Characterize the
aquifer thickness, ground-water flow rate
and direction, including seasonal and
temporal fluctuations in flow, effect of site
construction and operations on ground-
water flow direction, and variations in
ground-water elevation. To determine
ground-water flow directions, flow rates
and hydraulic gradient, a water level
monitoring program should be imple-
mented. This program should be struc-
tured to provide specific water level mea-
surements. Information on water level-
monitoring program and procedures for
obtaining accurate water level measure-
ments can be found in Solid Waste
Disposal Facility Criteria: Technical Manual
(EPA530-R-93-017).
Integrate all of this information to make the
best decisions regarding the number, locations,
depths, and screened intervals for wells to
monitor unit performance. As an example,
understanding the horizontal and vertical
ground-water flow makes it possible to esti-
mate where monitoring wells will most likely
intercept contaminant flow. The level of effort
to characterize a site sufficiently to design an
adequate ground-water monitoring system
depends on the geologic and hydrogeologic
complexity of the site. The complexity of a site
should not be assumed; a soil boring program
can help determine the complexity of a site's
hydrogeology. Appendix I presents a topical list
of more than 80 American Society for Testing
and Materials (ASTM) guides and practices
related to waste and site characterization and
sampling. Appendix I, Section A.2 identifies 31
major ASTM guides related to site characteriza-
tion. (See, Ground-Water Monitoring: Draft
Technical Guidance, EPA530-R-93-001 and Solid
Waste Disposal Facility Criteria: Technical
Manual, EPA530-R-93-017 for additional infor-
mation on ground-water monitoring.)
9-3
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Ensuring Long-Term Protection—Monitoring Per/c
ormance
B. Basics of Ground-Water
Monitoring
The basic elements; of a ground-water moni-
toring program include:
• The monitoring method;
• The number of wells;
• Location and screened intervals of wells;
• Well design, installation, and develop-
ment;
• The duration and frequency of monitor-
ing; and
• Sampling parameters to be monitored.
The remainder of this section provides a
brief overview of the six basic elements of a
ground-water monitoring program.
1. Monitoring Methods
Ground-water monitoring usually involves
installation of permanent monitoring wells for
periodic collection of ground-water samples.
Waste migration can be monitored by sam-
pling ground water directly for contaminants
or by sampling ground water for geophysical
parameters. Ground water also can be sampled
directly through semi-permanent conventional
monitoring wells or by temporary direct-push
sampling. Conventional monitoring wells,
direct-push sampling, and geophysical meth-
ods are described below.
a. Conventional Monitoring
Wells
The conventional monitoring well is the
most common well type used to target a single
screened interval. Figure 1 presents an illustra-
tion of a single screened interval. Specific con-
struction features are described in more detail
below. The conventional monitoring well is
semi-permanent, meaning it can be used for
sampling over an extended period of time and
should be located by surveyed reference
points. To monitor more than one depth at a
single location, install conventional monitoring
wells in clusters or with multilevel sampling
devices.
b. Direct-Push Ground-Water
Sampling
Using the direct-push technique, ground
water is sampled by hydraulically pressing
and/or vibrating a probe to the desired depth
and retrieving a ground-water sample through
the probe. The probe is removed for reuse
elsewhere after the desired volume of ground
water is extracted.
What are the benefits of direct-
push sampling?
Given favorable geology the direct-push
method of ground-water sampling can be a
simpler and less expensive alternative to con-
ventional wells. Conventional monitoring
wells, because they are semi-permanent, gen-
erally cost more and take longer to install.
Direct-push technology, however, does not
provide a semi-permanent structure from
which to sample the ground water over an
extended period of time, as do conventional
wells.
In sandy aquifers, however, the direct-push
technology can be used to install a well similar
to a conventional monitoring well. Relatively
recent advances in direct-push technology use
pre-packed screens with grouts and seals
attached to a metal pipe that are driven into
the ground, forming an assembly similar to a
conventional well. Consult with the appropri-
ate state agency to determine whether direct-
push well installations are acceptable.
9-4
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Ensuring Long-Term Protection—Monitoring Performance
Figure 1. Cross-Section of a Generic Monitoring Well
VENTED WELL CAP
GASVENTTUBE
HA GRAVEL FOR EASY RETRIEVAL OF TOOLS AND TO
REVENT SMALL ANIMAL/INSECT ENTRANCE
THROUGH DRAIN
FORMED PADS
PROTECTIVE CASING FILLED WITH
CEMENT ABOVE LEVEL OF PAD
STEEL PROTECTIVE CASING
SURVEYOR'S PIN
FORMED CONCRETE WELL APRON
CONTINUOUS POUR CONCRETE SURFACE SEAL
AND WELL APRON
NEAT CEMENT
WELL DIAMETER =4"
BOREHOLE DIAMETER = 10° TO 12"
V- 2' VERY FINE SAND
BENTONITE CLAY SLURRY - 2'
FILTER PACK (2' ABOVE SCREEN)
SCREENED INTERVAL
CENTRALIZER
SUMP/SEDIMENT TRAP
BOTTOM CAP
c. Geophysical Methods
Geophysical methods measure potential
changes in ground-water quality by measur-
ing changes in the geophysical characteristics
of the sub-surface soils, and in some cases, in
the ground water itself. For example, increas-
es in the levels of certain soluble metals in
ground water can change the resistive proper-
ties of the ground water, which can be mea-
sured using surface resistive technologies.
Similarly, changes in the resistive properties
of the vadose zone may indicate the migra-
tion of leachate toward ground water.
Geophysical characteristics, such as DC-resis-
tivity, electromagnetic induction, pH, and
temperature, can provide important prelimi-
nary indications of the performance of the
9-5
-------
Ensuring Long-Term. Protection—Monitoring Per/c
ormance.
waste unit liner design. Consult with the
appropriate state agency regarding the use of
a geophysical method. (See Subsurface
Characterization and Monitoring Techniques,
EPA625-R-93-003a, for additional informa-
tion on the use of geophysical methods.)
How useful is geophysical
method data?
Geophysical methods are more commonly
used to map the initial extent of contamina-
tion at waste management units than for
ongoing monitoring. Initial monitoring data
can guide placement of permanent monitor-
ing wells for ongoing monitoring. As dis-
cussed later, geophysical methods, used in
conjunction with ground-water monitoring,
can reduce the frequency of well sampling,
which could reduce-monitoring costs. The
usefulness of geophysical methods, however,
will depend on the local hydrogeology, the
contaminant concentration levels, and type of
contaminants
2. Number of Wells
A ground-water monitoring system
requires a minimum of one upgradient or
background monitoring well and three
downgradient monitoring wells to make sta-
tistically meaningful comparisons of ground-
water quality. The actual number of upgradi-
ent and downgradient wells will vary from
unit-to-unit and will depend on the actual
site-specific conditions. The upgradient or
background well(s) permit the assessment of
background quality of the onsite ground
water, and the downgradient wells permit
detection of any contaminant plumes from a
waste management unit. This configuration
of one upgradient and three downgradient
wells may be adequate when hydrologic con-
ditions and potential contaminant movement
are straightforward.
How many wells are needed?
To determine the number of monitoring
wells, evaluate the following factors:
• Geology of the waste management unit
site;
• Ground-water flow; direction and velocity,
including seasonal and temporal fluctua-
tions;
• Permeability or hydraulic conductivity of
any water-bearing formations; and
• Physical/chemical characteristics of con-
taminants.
The number of wells is dictated by the lat-
eral and vertical placement of monitoring
wells. Site-specific hydrogeologic data
obtained during site characterization should
be used to determine the lateral placement of
monitoring wells and to select the length and
vertical position of monitoring well intakes.
The lateral placement of monitoring wells
should be based on the number and spatial
distribution of potential contaminant migra-
tion pathways and on the depths and thick-
ness of stratigraphic horizons that can serve
as contaminant migration pathways. The ver-
tical position and lengths of monitoring well
intakes are functions of hydrogeologic factors
and the chemical and physical characteristics
of contaminants.
The local ground-water flow direction and
gradient are the major factors in determining
lateral placement of monitoring wells. In a
homogenous setting, well placement can be
based on general aquifer characteristics and
potential contaminant fate and transport
characteristics. However, geology is variable
and preferential pathways exist that control
migration of contaminants. The next section
provides information on the lateral and verti-
cal placement of monitoring wells.
A larger number of monitoring wells may
be needed at sites with complex hydrogeology.
9-6
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Ensuring Long-Term Protection—Monitoring Performance
If a site has multiple waste management units,
use of a multi-unit ground-water monitoring
system may reduce the necessary number of
wells. Consult with the appropriate state
agency when determining a site's ground-water
monitoring well requirements.
3. Lateral and Vertical Placement
of Wells
Monitoring wells must yield ground-water
samples from the targeted aquifer(s) that are
representative of both the quality of back-
ground ground water and the quality of ground
water at a downgradient monitoring point.
The lateral and vertical placement of moni-
toring wells is very site-specific. Locate moni-
toring wells at the closest practicable distance
from the waste management unit boundary to
detect contaminants before they migrate away
from the unit. Early detection provides a
warning of potential waste management unit
design failure and allows time to implement
appropriate abatement measures and poten-
tially eliminate the need for more extensive
corrective action. It also reduces the area
exposed and may limit overall liability.
a. Lateral Placement
Monitoring wells should be placed laterally
along die down gradient edge of the waste
management unit to intercept potential conta-
minant migration pathways. Ground-water
flow direction and gradient are two major
determining factors in monitoring well place-
ment. The number and spatial distribution of
potential contaminant migration pathways and
the depths and thickness of stratigraphic hori-
zons that can serve as contaminant migration
pathways also must be considered. In homoge-
neous, isotropic hydrogeologic sites ground-
water flow direction and gradient, along with
the potential contaminant chemical and physi-
cal characteristics, will primarily determine lat-
eral well placement. In more complex site
where hydrogeology and geology are variable
and preferential pathway exist, (a heteroge-
neous, anisotropic hydrogeologic site) the well
placement determination becomes more com-
plex. Potential migration pathways are influ-
enced by site geology including varying
hydraulic conductivity, fractured or faulted
zones, and soil chemistry. Human-made fea-
tures that influence ground-water flow must
also be considered. These features may include
things such as ditches, filled areas, buried pip-
ing, buildings, leachate collection systems and
other adjacent disposal units.
Another point of consideration is seasonal
changes in ground-water flow. Seasonal
changes in ground-water flow can result from
tidal influences, lake or river stage fluctuations,
well pumping, or land use pattern changes. At
some sites it may even be possible that ground
water flows in all directions from a waste man-
agement unit. These contingencies may require
placement of monitoring wells in a circular
pattern to monitor on all sides of the waste
management unit. Seasonal fluctuations may
cause certain wells to be downgradient only
part of the time, but such configurations
ensure that releases will be detected.
Lateral placement of monitoring wells also
must be based upon the chemical and physi-
cal characteristics of a waste management
unit's potential contaminants. Consider
potential contaminant characteristics such as
solubility, Henry's law constant, partition
coefficients, specific gravity (density), poten-
tial for natural attenuation and the resulting
reaction or degradation products, and the
potential for contaminants to degrade confin-
ing layers. A Dense non-aqueous phase liquid
(DNAPL), for instance, because of its density
may not necessarily migrate only in the direc-
tion of the ground-water flow. The presence
of DNAPL, therefore, may require placing
wells in more locations than just the normal
downgradient sites.
9-7
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Ensuring Long-Term Protection—Monitoring Performance
b. Vertical Placement and
Screen Lengths
Similar to lateral placement, vertical well
placement in the ground water around a
waste management unit is determined by
geologic and hydrogeologic factors, as well as
the chemical and physical characteristics of
the potential contaminants. The vertical
placement of each well and its screen lengths
will be determined by the number and spatial
distribution of potential contaminant migra-
tion pathways and the depths and thickness
of potential migration pathways. Site-specific
geology, hydrogeology, and constituent char-
acteristics influence the location, size, and
geometry of potential contaminant plumes,
which in mm determine monitoring well
depths and screen lengths.
The-chemical and physical characteristics
of potential contaminants from a waste man-
agement unit plays a significant role in deter-
mining vertical placement. The specific prop-
erties of a particular contaminant will deter-
mine what potential migration pathway it
may take in an aquifer. The specific charac-
teristics of a contaminant, such as its solubili-
ty, Henry's law constant, partition coefficients,
specific gravity (density), potential for natural
attenuation and the resulting reaction or
degradation products, and the potential for
contaminants to degrade confining layers,
will all influence the vertical placement and
screen lengths of a unit's monitoring wells. A
DNAPL, for instance, will sink to the bottom
of an aquifer and migrate along geologic gra-
dients (rather than hydrogeologic gradients),
thus requiring a mdnitoring well's vertical
placement to correspond with the depth of
the appropriate geologic feature. LNAPLs
(light nonaqueous phase liquids) on the other
hand would move along the top of an aquifer,
and require wells and wells screens at the
surface of the aquifer.
Well screen lengths are also determined by
site and constituent specific parameters.
These parameters and the necessity of taking
vertically discrete ground-water samples, fac-
tor into the determination of well screen size.
Highly heterogeneous (complex) geologic
sites require shorter well screen lengths to
allow for the sampling of discrete migration
pathways. Screens that span more than a sin-
gle contaminant migration pathway may
cause cross contamination, possibly increas-
ing the extent of contamination. Shorter
screen lengths allow for a more concentrated
monitoring of the aquifer or the portion of
the aquifer of concern. Excessively large well
screens may lead to the dilution of samples
making contaminant detection more difficult.
The depth or thickness of an aquifer also
determines the length of the well screen. Sites
with highly complex geology or relatively
thin aquifers may require multiple screens at
varying depths. Conversely, an extremely
thick and homogenous aquifer may allow for
fewer wells with longer screen lengths.
Consult with state officials on the lateral
and vertical placement of monitoring wells.
In the absence of specific state requirements,
it is recommended that the monitoring points
be no more than. 150 meters downgradient
from a waste management unit boundary, on
facility property, and placed in potential cont-
amination migration pathways. This maxi-
mum distance is consistent with the 40 CFR
Part 258 criteria for municipal solid waste
landfills and approaches that many states
have adopted in order to protect waters of
the state.
4. Monitor Well Design,
Installation, and Development
Ground-water monitoring wells are tai-
lored to suit the hydrogeologic setting, the
type of constituents to be monitored, the
9-8
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Ensuring Long-Term Protection—Monitoring Performance
Table 1
Factors Affecting Number of Wells Per Location (CLUSTER)
One Well per Sampling Location
More Than One Well Per Sampling Location
No light non-aqueous phase liquids
(LNAPLs) or dense non-aqueous phase
liquids (DNAPLs) (immiscible liquid
phases)
Presence of LNAPLs or DNAPLs
Thin flow zone (relative to screen
length)
Horizontal flow predominates
Thick flow zones
Vertical gradients present
Homogeneous isotropic uppermost
aquifier, simple geology
Heterogeneous anisotropic uppermost aquifier,
complicated geology
- multiple, interconnected aquifiers
- variable lithology
- perched water zones
- discontinuous structures
Discrete fracture zones in bedrock
Solution conduits, such as caves, in karst terrains
Cavernous basalts
overall purpose of the monitoring program,
and other site-specific variables. Consult with
the state agency and qualified professionals to
discuss the construction specifications for
ground-water monitoring wells before begin-
ning well designs. Figure 1 illustrates the
monitoring well design components that are
discussed in this section. Appendix I, Section
A.3 identifies ASTM guides and practices
related to monitoring well design, construc-
tion, development, maintenance, and decom-
missioning. EPA's Handbook of Suggested
Practices for the Design and Installation of
Ground-Water Monitoring Wells (EPA600-4-89-
034) also contains this information.
a. Well Design
The typical components of a monitoring
well include a well casing, a well intake, a fil-
ter pack, an annular and surface seal, and
surface completion. Each of these compo-
nents is briefly
described below.
Web Casing
The well cas-
ing is a pipe
which is
installed tem-
porarily or per-
manently to
counteract cav-
ing, to advance a
borehole, and to
isolate the zone
9-9
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Ensuring Long-Term. Protection—Monitoring Performance
being monitored. The well casing provides
access from the surface of the ground to some
point in the subsurface. The casing, associat-
ed seals, and grout prevent borehole collapse
and interzonal hydraulic communication.
Access to the monitored zone is through the
casing and into either the open borehole or
the screened intake. The casing thus permits
piezometric head measurements and ground-
water quality sampling.
A well casing can be made of any rigid
tubular material. The most frequently evalu-
ated characteristics that directly influence the
performance of casing material in ground-
water monitoring applications are strength,
chemical resistance, and interference.
Monitoring well casings should be strong
enough to resist the forces exerted on it by
the surrounding geologic materials and the
forces imposed on it during installation.
Casings should exhibit structural integrity for
the expected duration of the monitoring pro-
gram under natural and man-induced subsur-
face conditions. Well casing materials should
also be durable enough to withstand galvanic
or electrochemical corrosion and chemical
degradation. Metallic casing materials are
most subject to corrosion and thermoplastic
casing materials are most subject to chemical
degradation. In addition, casing materials
should not exhibit a tendency to either sorb
(take constituents out of solution by either
adsorption or absorption) or leach chemical
constituents from or into the water that is
sampled from the well. If casing materials
sorb selected constituents, the water-quality
sample will not be representative. The three
most common types of casing materials are
fluoropolymer materials, including polytetra-
fluoroethylene and tetrafluoroethylene; metal-
lic materials, including ^carbon steel, galva-
nized steel, and stainless steel; and thermo-
plastic materials, including polyvinyl chloride
and acrylonitrile butadiene styrene.
Well Screen
A well screen is a filtering device used to
retain the primary or natural filter pack; usu-
ally a cylindrical pipe with openings of a uni-
form width, orientation, and spacing. It is
often necessary to design the monitoring well
with a well intake (well screen) placed oppo-
site the zone to be monitored. The intake
should be surrounded by materials that are
coarser, have a uniform grain size, and have a
higher permeability than natural formation
material. This allows ground water to flow
freely into the well from the adjacent forma-
tion material while minimizing or eliminating
the entrance of fine-grained materials such as
clay or sand, into the well.
A well screen design needs to consider:
intake opening (slot) size, intake length, intake
type, and corrosion and chemical degradation
resistance. Proper sizing of monitoring well
intake openings is one of the most important
aspects of monitoring well design. The selec-
tion of the length of a monitoring well intake
depends on the purpose of the well. Most
monitoring wells function as both ground-
water sampling points and piezometers2 for a
discrete interval. To accomplish these objec-
tives, well intakes are typically 2 to 10 feet in
length and only rarely equal or exceed 20 feet
in length. The hydraulic efficiency of a well
intake depends primarily on the amount of
open area available per unit length of intake.
The amount of open area in a well intake is
controlled by the type of well intake and open-
ing size. Many types of well intakes have been
used in monitoring wells, including: the lou-
vered (shutter-type) intake, the bridge-slot
intake, the machine-slotted well casing, and
the continuous-slot wire-wound intake.
Filter Pack
Filter pack is the material placed between
the well screen and the borehole wall which
allows ground water to flow freely into the
2A piezometer is a non-pumping well, generally of small diameter, used to measure
water table.
9-10
the elevation of the
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Ensuring Long-Tenn Protection—Monitoring Performance
well while filtering out fine-grained materials.
In the construction of a monitoring well, dis-
tort the natural stratigraphic setting as little as
possible. Hence, it may be necessary to filter-
pack boreholes that are over-sized with regard
to the casing and well intake diameter. The fil-
ter pack prevents formation material from
entering the well intake and helps stabilize the
adjacent formation. The filter-pack materials
should be chemically inert to alleviate the
potential for alteration of ground-water sample
quality Commonly used filter-pack materials
include clean quartz sand, gravel, and glass
beads. The filter pack should generally extend
from the bottom of the well intake to approxi-
mately two to five feet above the top of the
well intake, provided the interval above the
well intake does not result in a hydraulic con-
nection with an overlying zone.
Annular Sed
Annular space is the space between the
casing and the borehole wall. Any annular
space that is produced as a result of the
installation of the well casing in a borehole
provides a channel for vertical movement of
water and/or contaminants unless the space is
sealed. The annular seal in a monitoring well
is placed above the filter pack in the annulus
between the borehole and the well casing.
The seal serves several purposes: to provide
protection against infiltration of surface water
and potential contaminants from the ground
surface down the casing/borehole annulus; to
seal off discrete sampling zones, both
hydraulically and chemically; and to prohibit
vertical migration of water. Such vertical
movement can cause "cross contamination"
which can influence the representativeness of
ground-water samples. The annular seal may
be comprised of several different types of per-
manent, stable, low-permeability materials
including pelletized, granular or powdered
bentonite, neat cement grout, and combina-
tions of both. The most effective seals are
obtained by using expanding materials that
will not shrink away from either the casing or
the borehole wall after curing or setting.
Surface Seal
A surface seal is an above-ground seal that
protects a monitoring well from surface water
and contaminant infiltration. Monitoring wells
should have a surface seal of neat cement or
concrete surrounding the well casing and filling
the annular space between the casing and the
borehole at the surface. The surface seal may be
an extension of the annular seal installed above
the filter pack or it may be a separate seal
emplaced on top of die annular seal. The sur-
face seal will generally extend to at least three
feet away from the well casing at the surface
and taper down to the size of the borehole
widrin a few feet of the surface. In climates
with alternating freezing and thawing condi-
tions, the cement surface should extend below
the frost depth to prevent potential well dam-
age caused by frost heaving.
Surface Completions
Surface completions are protective casings
installed around the well casing. Two types of
surface completions are common for ground-
water monitoring wells: above-ground com-
pletion, and flush-to-ground completion. The
primary purposes of either type of completion
are to prevent surface run-off from entering
and infiltrating down the annulus of the well
and to protect the well from accidental dam-
age or vandalism. In an above-ground com-
pletion, the preferred alternative, a protective
casing is generally installed around the well
casing by placing the protective casing into
the cement surface seal while it is still wet and
uncured. The protective casing discourages
unauthorized entry into the well, prevents
damage by contact with vehicles, and reduces
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Ensuring Long-Tenn Protection—Monitoring Performance
degradation caused by direct exposure to sun-
light. The protective casing should be fitted
with a locking cap and installed so that there
is at least one to two inches clearance between
the top of the in-place inner well casing cap
and die bottom of the protective casing lock-
Ing cap when in the locked position. Like the
inner well casing, the outer protective casing
should be vented near the top to prevent the
accumulation and entrapment of potentially
explosive gases and to allow water levels in
the well to respond naturally to barometric
pressure changes. Additionally, the outer pro-
tective casing should have a drain hole
installed just above the top of the cement level
in the space between the protective casing and
the well casing. This drain allows trapped
water to drain away from the casing. In high-
traffic areas or in areas where heavy equip-
ment may be working, consider the installa-
tion of additional protection such as "bumper
guards." Bumper guards are brightly-painted
posts of wood, steel, or some other durable
material set in cement and located within
three or four feet of the well.
b. Well Installation
To ensure collection of representative
ground-water samples, the well intake, filter
pack, and annular seal must be properly
installed. In cohesive unconsolidated material
or consolidated formations, well intakes should
be installed as an. integral part of the casing
string by lowering die entire unit into the open
borehole and placing the well intake opposite
die interval to be monitored. Centralizing
devices are typically used to center the casing
and intake in the borehole to allow uniform
installation of the filter pack material around
the well intake. There are odier standardized
techniques to ensure the proper installation of
wells in non-cohesive, unconsolidated materi-
als, such as a casing hammer, a cable tool tech-
nique, the dual-wall reverse-circulation
method, or installation through the hollow
stem of a hollow-stem auger.
c. Well Development
Monitoring well development is the removal
of fine paniculate matter, commonly clay and
silt, from the geologic formation near die well
intake. If paniculate matter is not removed, as
water moves through the formation into the
well, the water sampled will be turbid, and the
viability of the water quality analyses will be
impaired. When pumping during well develop-
ment, the movement of water is unidirectional
toward the well. Therefore, there is a tendency
for the particulates moving toward the well to
"bridge" together or form blockages that restrict
subsequent paniculate movement. These
blockages may prevent the complete develop-
ment of the well capacity. This effect potentially
impacts the quality of die water entering the
well. Development techniques should remove
such bridges and encourage die movemenrof
particulates into the well. These particulates
can then be removed from the well by bailer or
pump and, in most cases, the water produced
will subsequently be dear and non-turbid. In
most instances, monitoring wells installed in
consolidated formations can be developed
without great difficulty. Monitoring wells also
can usually be developed rapidly and without
great difficulty in sand and gravel deposits.
However, many installations are made in thin,
silty and/or clayey zones. It is not uncommon
for these zones to be difficult to develop suffi-
ciently for adequate samples to be collected.
5. Duration and Frequency of
Monitoring
The duration of ground-water monitoring
will depend on the length of the active life of
the waste management unit and of its post-
closure care period. Continued monitoring
after a waste management unit has closed is
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Ensuring Long-Tenn Protection—Monitoring Performance
important because the potential for contami-
nant releases remains even after a unit has
stopped receiving waste.
The ground-water monitoring program
establishes the frequency of sampling.
Monitoring frequency should be sufficient to
allow detection of ground-water contamina-
tion. This frequency usually ranges from
quarterly to annually. The ground-water mon-
itoring program also establishes a list of con-
stituents, based on the specifics of the site,
whose levels are monitored to indicate if the
site's ground-water quality is changing.
What site characteristics should
be evaluated to determine the
frequency of monitoring?
Ground-water flow velocity is important in
establishing an appropriate ground-water moni-
toring frequency to ensure that samples collect-
ed are physically and statistically independent.
For example, in areas with high ground-water
flow velocity, more frequent monitoring may be
necessary to detect a release before it migrates
and contaminates large areas. In areas with low
flow velocity, less frequent monitoring may be
appropriate. Analyze background ground-water
conditions, such as flow directions and veloci-
ties and seasonal ground-water fluctuations, to
help determine a suitable monitoring frequency
for a site. Consult with the state agency to
determine an appropriate monitoring frequency
In the absence of state requirements, it is rec-
ommended that semi-annual monitoring be
conducted to detect contamination as pan of a
basic monitoring program.
6. Sampling Parameters
Selection of parameters to be monitored in
a ground-water monitoring program is based
on the characteristics of waste in the man-
agement unit. Additional sampling and
analysis information can be found in EPA
SW-846 Test Methods for Evaluating Solid
Waste and in ASTM's standards. Appendix I,
Section A. 1 identifies 18 ASTM guides and
practices for performing waste characteriza-
tion and sampling.
What are sampling parameters?
Analyzing a large number of ground-water
quality parameters in each sampling episode
can be costly. To minimize expense, select
only contaminants that can be reasonably
expected to migrate to the ground water and
other geochemical indicators of contaminant
migration. These are called sampling parame-
ters. Sampling parameters should provide an
early indication of a release from a waste
management unit. Once contamination is
detected, consider expanding the original
sampling parameters and monitor for addi-
tional constituents to fully characterize the
chemical makeup of the release.
What sampling parameters
should be used?
Initially analyze a broader range of para-
meters to establish background ground-water
quality and use the results to select the sam-
pling parameters to be monitored subse-
quently at a site. Due to the broad universe of
industrial solid waste, it is not possible to
recommend a list of indicator parameters that
are capable of identifying every possible
release. Table 2 lists potential parameters for
a basic ground-water monitoring program, by
different categories. Modify these parameters,
as appropriate, to address site-specific cir-
cumstances.
Use knowledge of the actual waste
streams or existing analytical data as a pre-
liminary guide for what should be monitored,
or use leachate sampling data to select or
9-13
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Ensuring Long-Term. Protection—Monitoring Performance
; Table 2
Potential Parameters for basic Ground-Water Monitoring
(Potential Parameters Should be Selected Based on Site-Specific Circumstances)
Category
Field-Measured Parameters
Leachate Indicators
Additional Major Water Quality
Parameters
Minor and Trace Inorganics
Specific (Parameters
Temperature
pH
Specific electrical conductance
Dissolved oxygen
Eh oxidation-reduction potential
Turbidity
Total organic carbon (TOC-filtered)
pH
Specific conductance
Manganese (Mn)
Iron (Fe)
Ammonium (NH+ as N)
Chloride
Sodium (Na)
Biochemical oxygen demand (BOD)
Chemical oxygen demand (COD)
Volatile organic compounds (VOCs)
Total Halogenated Compounds (TOX)
Total Petroleum Hydrocarbons (TPH)
Total dissolved solids (TDS)
Bicarbonate (HCOs)
Boron (Bo)
Carbonate
Calcium (Ca)
Fluoride (Fl)
Magnesium (Mn)
Nitrate (as N)
Nitrogen (dissolved Ni)
Potassium (K)
Sulfate (SOz)
Silicon (tfcSiOO
Strontium (Sr)
Total dissolved solids (TDS)
Initial background sampling of inorganics for
which drinking water standards exist (arsenic,
barium, cadmium, chromium, lead, mercury,
selenium, silver); ongoing monitoring of any con-
constituents showing background near or above
drinking water standards
9-14
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Ensuring Lorag-Tenn Protection—Monitoring Performance
Table 3
Factors Affecting Number of Wells Per Location (CLUSTER)
Monitoring Component Recommended Minimum
Number of Wells
Point of Monitoring
Duration of Monitoring
Frequency of Monitoring
Sampling Parameters
Minimum 1 upgradient and 3 downgradient.3
As appropriate for site conditions and waste manage-
ment unit boundary or out to 150 meters downgra-
dient of the waste management unit area.4
Active life plus post-closure care.
Semi-annual during active life.5
Metal and organic scans, use of indicators, leachate
analysis, and/or knowledge of the waste.
See Table 2
adjust sampling parameters. Where there is
uncertainty concerning the chemistry of the
waste, perform metal and organic scans at a
minimum. Consult with the state agency to
ensure that appropriate sampling parameters
are selected.
What are the minimum compo-
nents of a basic monitoring pro-
gram?
Table 3 summarizes the recommended
minimum components of a basic ground-
water monitoring program described above.
Potential modifications to the basic monitor-
ing program that may be appropriate based
on site-specific waste management unit con-
ditions are discussed later in this chapter.
C Sampling and Analytical
Protocols and Quality
Assurance and Quality
Control
The best designed monitoring program
will not provide useful data without sound
sampling and analytical protocols. Sampling
and analytical protocols are generally contam-
inant specific. A correctly designed and
implemented sampling and analysis protocol
ensures that sampling results accurately rep-
resent ground-water quality and can be com-
pared over time. The accurate representation
is achieved through statistical analysis.
Whether an established quality assurance
and quality control (QA/QC) program is
required on a federal, state, or local level, it is
a good management practice to develop and
strictly implement such a plan. The sampling
protocol should incorporate federal, state,
3The actual number of both upgradient and downgradient wells will vary from unit-to-unit and will
depend on the actual site-specific conditions.
4Rationale for discussion that point of monitoring could be out to 150 meters from a unit's boundary was
for consistency with the 40 CFR Part 258 criteria.
5Also, ground-water flow rate may dictate that more or less frequent monitoring may be appropriate.
More frequent monitoring might be appropriate at the start of a monitoring program to establish back-
ground. Less frequent and/or reduced in scope monitoring may also be appropriate during the post-clo-
sure care period.
9-15
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Ensuring Long-Term Protection—Monitoring Performance
and local QA/QC requirements. Ground-
water sampling QA/QC procedures detail
steps for collection and handling of ground-
water samples. Sample collection, preserva-
tion, shipment, storage, and analysis should
be performed in accordance with an
approved QA/QC program to ensure data of
known quality are generated.
Rely on qualified professionals who are
properly trained to conduct sampling.
Poorly-conducted sampling may give false
evidence of a contamination problem or can
miss early warnings of contaminant leaching.
Erring in either direction is an avoidable and
costly mistake.
At a minimum, include the following in
your sampling protocol:
• Data quality objectives including lists of
important tracking parameters, such as
the date and name of samples;
• Sample collection procedures, including
description of well purging methods, lists
of necessary field analyses, and sample
withdrawal method;
• Instructions for sample preservation and
handling;
• Other QA/QC procedures such as chain-
of-custody; and
• The name of the person who conducted
the sampling.
States have developed guidance docu-
ments addressing sampling plans, protocols,
and reports. Work with the state to develop
an effective sampling protocol.
1. Data Quality Objectives
In any sampling and analysis plan, it is
important to understand the data needs for a
ground-water monitoring program. Tailoring
sampling protocol and analytical work to
data needs ensures cost-efficient sampling. A
sampling and analysis plan should specify:
(1) clear objectives (such as what data is
needed and how the data is to be used); (2)
lists of target contaminants; and (3) level of
accuracy requirements for data to be conclu-
sive. Chapter 1 of EPA SW-846 Test Methods
for Evaluating Solid Waste and ASTM Guide
D5792 provide guidance on developing data
quality objectives for waste management
activities.
2. Sample Collection
Sample collection techniques should be
carefully designed to ensure sampling quality
and avoid cross-contamination or back-
ground contamination of ground-water sam-
ples. Appendix I, Section A.4 lists ASTM
guides for ground-water sampling. Consider
the following factors when preparing for
sample collection.
• Well Inspection. Check the wells for
cracks and/or loose casings.
• Water Elevation. Take water level eleva-
tion measurements and calculate the
amount of stagnant water that needs to
be purged.
• Well Purging. Because the water standing
in a well prior to sampling may not rep-
resent in situ ground-water quality, purge
9-16
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Ensuring Long-Tenn Protection—Monitoring Performance
a sufficient volume of stagnant water
from each monitoring well and filter pack
prior to sampling. Purging should remove
standing ground water from the well at
low flow rates. A low purge rate will
reduce the possibility of stripping VOCs
from the water and will reduce the likeli-
hood of mobilizing colloids in the sub--
surface. (See Low Flow Ground Water
Sampling, EPA540-S-95-504, for addition-
al information on low flow well purging
and sampling techniques to improve rep-
resentativeness of ground-water samples.)
Sample Withdrawal and Collection. The
equipment used to withdraw a ground-
water sample from a well should be
appropriate for the monitoring parame-
ters. Sampling equipment should cause
minimal agitation of the sample and
reduce or eliminate contact between the
atmosphere and the sample during trans-
fer to ensure a sample is representative of
the ground water.
Field Analysis. Some constituents or
parameters may be physically or chemi-
cally unstable and should be tested at the
well site rather than waiting for shipment
to a laboratory. Examples of unstable
parameters include pH, redox (oxidation-
reduction) potential, dissolved oxygen,
temperature, and specific conductance.
3. Sample Preservation and
Handling
Sample preservation and handling proto-
cols are designed to minimize alterations of
the chemistry of water quality samples
between the time the sample is collected and
when it is analyzed. Consider the following.
• Sample Containers. To avoid altering
sample quality, transfer samples from the
sampling equipment directly into a cont-
aminant free container. U.S. EPA SW-846,
identifies
proper sample
containers for
different con-
stituents.
Samples
should never
be combined
in a common
container and
then split later
in the field.
Sample
Preservation.
The time be-
tween sampling and sample analysis can
range from several hours to several
weeks. Immediate sample preservation
and storage assists in maintaining the
natural chemistry of the samples. Refer to
the latest edition of SW-846 for specific
preservation methods and holding times
for each constituent analyzed. SW-846
recommends preservation methods, such
as pH adjustment, chemical addition, and
refrigeration.
Sample Transport. To document sample
possession from the time of collection to
the laboratory, include a chain-of-custody
record in every sample shipment. A
chain-of-custody record generally
includes the date and time of collection,
signatures of those involved in the chain
of possession, time and dates of posses-
sion, and other notations to trace samples.
4. Quality Assurance and Quality
Control
To verify the accuracy of field sampling
procedures, collect field quality control sam-
ples, such as trip blanks, equipment blanks,
and duplicates. Analyze quality control sam-
ples for the required monitoring parameters.
9-17
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Ensuring Long-Term Protection—Monitoring Perfc
•ormance
Other QA/QC practices include sampling
equipment calibration, equipment decontam-
ination, and use of chain-of-custody forms.
ASTM Guide D-5283 provides guidance on
QA/QC planning and implementation for
waste management activities. Chapter 1 of
SW-846 also provides guidance on QA/QC
practices.
! I
5. Analytical Protocols
Ground-water monitoring programs
should employ analytical methods that accu-
rately measure the constituents being moni-
tored. SW-846 recommends specific analyti-
cal methods to test for various constituents.
Similarly, individual states may recommend
other analytical methods for ground-water
analysis.
Ensure the reliability and validity of ana-
lytical laboratory data as part of the ground-
water monitoring program. Most facility
managers use commercial laboratories to
conduct analyses of ground-water samples;
others may use their own internal laborato-
ries if they are equipped and qualified to per-
form such analyses. In selecting an analytical
laboratory, check for the following: laborato-
ry certification by a state or professional asso-
ciation for the type of analyses needed; quali-
fied lab personnel; good quality analytical
equipment with back-up instrumentation; a
laboratory QA/QC program; proper lab docu-
mentation; and adherence to standard proce-
dures for data handling, reporting, and
record keeping. Laboratory QA/QC pro-
grams should describe chain-of-custody pro-
cedures, calibration procedures and frequen-
cy, analytical standard operating procedures,
and data validation and reporting proce-
dures. A good QA/QC program helps ensure
the accuracy of laboratory data.
D. Analysis of Monitoring
Data, Contingency
Planning, and
Assessment Monitoring
Once ground-water monitoring data have
been collected, analyze, the data to determine
whether contaminants are migrating in the
subsurface from a waste management unit.
Develop a contingency plan to address the
situations where contamination is detected.
1. Statistical Approaches
Statistical procedures should be used to
evaluate ground-water monitoring data and
determine if there is evidence of a release
from a waste management unit. Anomalous
data may result from sampling uncertainty,
laboratory error, or seasonal changes in nat-
ural site conditions. Qualified statistical pro-
fessionals can determine if statistically signifi-
cant changes in water quality have occurred
or whether the quantified differences could
have arisen solely because of one of the
above-listed factors. After consulting with the
state agency and statistical professional and
selecting a statistical approach, continue to
use the selected method in all statistical
analyses. Do not switch to a different test
when the first method generates unfavorable
results.
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Ensuring Long-Term. Protectiaa—Monitoring Performance
What is important in selecting a
statistical approach?
An appropriate statistical approach will
minimize false positives or negatives in terms
of potential releases. The approach should
account for historical data, site hydrogeologic
conditions, site operating practices, and sea-
sonal variations. While there are numerous
statistical approaches used to evaluate
ground-water monitoring data, check with
the state to determine if a specific statistical
approach is recommended.
Common methods for evaluating ground-
water monitoring data include the following
statistical approaches:
• Parametric analysis of variance (ANOVA).
This analysis, as well as rank-based (non
parametric) ANOVA, attempts to deter-
mine whether different wells have signifi-
cantly different average concentrations of
constituents.
• Tolerance intervals. Tolerance intervals
are statistical intervals constructed from
data designed to contain a portion of a
population, such as 95 percent of all
sample measurements. These intervals
can be used to compare data from a
downgradient well to data from an upgra-
dient well.
• Prediction intervals. These intervals
approximate future sample values from a
population or distribution with a specific
probability. Prediction intervals can be
used both for comparison of downgradi-
ent wells to upgradient wells (inter-well
comparison) and for comparison of cur-
rent well data to previous data for the
same well (intra-well comparison).
• Control charts. These charts use historical
data for comparison purposes and are,
therefore, only appropriate for initially
uncontaminated wells.
There are many different ways to select an
appropriate statistical method. More detailed
guidance on statistical methods for ground-
water contaminant detection monitoring can
be found in U.S. EPA Addendum to Interim
Final Guidance Document on Statistical Analysis
of Ground-Water Monitoring Data at RCRA
Facilities (EPA530-R-93-003), U.S. EPA
Guidance Document on Statistical Analysis of
Ground-Water Monitoring Data at RCRA
Facilities-Interim Final Guidance, and ASTM
provisional guide PS 64-96 (Appendix I,
Section A.8.1).
2. Contingency Planning
Contingency plans identify the procedures
to follow if a statistically significant increase
in one or more contaminants has been detect-
ed. A contingency plan should include proce-
dures to determine whether an increase in
sample concentrations was caused by the
waste management unit or by unrelated fac-
tors; procedures for developing and conduct-
ing an assessment monitoring program; pro-
cedures for remediating the waste manage-
ment unit to stop the release of contaminants;
and a determination of the magnitude of con-
tamination that would require initiation of
corrective action, such as a statistical
exceedance of an MCL or HBN.
3. Assessment Monitoring
The purpose of assessment monitoring is
to evaluate the rate, extent, and concentra-
tions of contamination. Once a statistically
significant increase has been confirmed for
one or more of the sampling parameters,
determine whether the increase was caused
by factors unrelated to the unit. Factors unre-
lated to the unit that may cause an increase
in the detected concentration(s) are:
• Contaminant sources other than the
waste management unit being monitored;
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Ensuring Long-Term Protection—Monitoring Performance
• Natural variations in ground-water quality;
• Analytical errors;
• Statistical errors; and
• Sampling errors.
If the increase was caused by a factor
unrelated to the unit, then additional mea-
sures may not be necessary and the original
ground-water monitoring program can be
resumed. If, however, these factors have been
ruled out, begin an assessment monitoring
program. Consult with the state agency to
determine the type of assessment monitoring
to conduct at the unit. Assessment monitor-
ing typically involves resampling all wells,
both upgradient and downgradient, and ana-
lyzing the samples for a larger list of parame-
ters than used during the basic ground-water
monitoring program. More than one sam-
pling event may be necessary and additional
monitoring wells may need to be installed to
adequately determine the scope or extent of
any contamination. Work with state officials
to establish background concentrations and
ground-water protection standards for all
additional constituents that were detected
during assessment monitoring.
If assessment monitoring results indicate
there is not a statistically significant increase
in the concentrations of one or more of the
constituents over the established ground-
water protection standards, then resume the
original ground-water monitoring program.
If, however, there is a statistically significant
increase in any of these constituents, consult
with state officials to identify the next steps.
Typically, it may be necessary to install addi-
tional monitoring wells to characterize the
nature and extent of the contamination and
to notify persons who own or reside on the
land that directly overlies any part of the
plume of contamination if it has migrated
beyond the facility boundary.
Detection of contamination may be an
indicator that the design of a waste manage-
ment unit is not working properly. During
this assessment phase, component(s) of the
unit (cover, liner, or leachate collection sys-
tem) that are not working properly should be
determined and, if possible, remediated.
Sometimes sealing a hole in the liner of a
small surface impoundment may be sufficient
to stop the source of contamination. Other
times, more extensive response may be
required. One example could be the subsi-
dence of a unit's final cover creating a hole
that requires repairing of the final cover.
Evaluation of other remedial alternatives, as
discussed in the corrective action chapter,
may become necessary if waste system com-
ponents can not be remediated.
E. Potential Modifications
to a Basic Ground-Water
Monitoring Program
It may be appropriate to modify certain ele-
ments of a basic ground-water monitoring
program described above to accommodate site
specific circumstances. When using the IWEM
software to evaluate the need for a liner sys-
tem, if the recommendation is to use a com-
posite-liner, then the basic ground-water mon-
itoring program should probably be enhanced.
If the recommendation using the software is
that no liner is appropriate, then it may be
possible to scale back some aspects of the
basic ground-water monitoring program.
Components that may be subject to modifi-
cation include the duration and frequency of
monitoring, sampling parameters, and the use
of vadose zone monitoring. Possible modifica-
tions of these elements are discussed further
below. Consult with state officials on their
requirements for ground-water monitoring
programs. In some states, a unit may be eligi-
ble for a no-migration exemption from the
state's ground-water monitoring requirements.
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Ensuring Long-Tenn Protection—Monitoring Performance
1. Duration and Frequency of
Monitoring
The duration of monitoring (active life plus
post-closure care) is not likely to be modified
in either a reduced or an enhanced ground-
water monitoring program. Adjustments to the
frequency of monitoring, however, may be
appropriate, based primarily on the mobility of
contaminants and ground-water velocity. For
example, if the sampling parameters are slow
moving metals, annual rather than semi-annu-
al monitoring may be appropriate. Conversely,
quarterly monitoring might be required at a
unit with a rapid ground-water flow rate or a
mobile contaminant such as cyanide over a
permeable sand and gravel aquifer.
2. Sampling Parameters
The basic recommended ground-water
monitoring program already recommends the
use of a parameter list that is tailored to the
waste characteristics and site hydrogeology.
Where the use of the IWEM software indi-
cates no liner is appropriate, it may be possi-
ble to reduce the list of parameters routinely
analyzed in downgradient wells to only a few
indicator parameters. More complete analysis
would only be initiated if concentrations of
the indicator parameters indicate that conta-
minant movement has occurred.
3. Vadose Zone Monitoring
Vadose zone monitoring detects migration
of contaminants before they reach ground
water, serving as an early warning system if a
waste management unit is not functioning as
designed. The vadose zone is the region
between the ground surface and the saturated
zone. Depending on climate, soils, and geolo-
gy, the vadose zone may range in thickness
from several feet to hundreds of feet. Vadose
zone monitoring provides three main poten-
tial benefits: (1) early warning of contaminant
migration before it reaches the ground water,
(2) reduced time and cost of remediation,
and (3) possible reduction in ground-water
monitoring efforts. If site conditions permit,
it may be desirable to include vadose zone
monitoring as part of the overall ground-
water monitoring program. If vadose zone
monitoring is incorporated, the recommend-
ed number of ground-water monitoring wells
would still be determined by the basic
ground-water monitoring program, and back-
ground quality would still need to be charac-
terized with ground-water monitoring. The
ground-water monitoring program becomes a
backup, however, with full use only being
initiated if contaminant migration is detected
in the vadose zone.
The sections below describe some of the
commonly used methods for vadose zone
monitoring, vadose zone characterization,
and elements to consider in the design of a
vadose zone monitoring system.
a. Vadose Zone Monitoring
Methods
There are dozens of specific techniques for
indirect measurement and direct sampling of
the vadose zone. The more commonly used
methods with potential value for waste
management units are described briefly below.
Soil Water and. Tension Monitoring
Measuring changes in soil water content,
9-21
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Ensuring Long-Term Protection—Monitoring Performance
or soil water tension over time is a relatively
simple and inexpensive method for leak
detection. Periodic measurements of soil
water content or soil moisture tension
beneath a lined waste management unit
should show only small changes. Significant
increases in water content or decreases in soil
moisture tension would indicate a leak.
What method should be used to
measure soil moisture?
Soil moisture characteristics can be mea-
sured in two main ways: (1) water content,
usually expressed as weight percentage, and
(2) soil moisture tension or suction, which
measures how strongly water is held by soil
particles due to capillary effects. As soil water
content increases, soil moisture tension
decreases. Measurements will not indicate,
however, whether contaminants are present.
Figure 2 shows three major methods that
are available for in-situ monitoring of soil
moisture changes. Porous cup tensiometers
(Figure 2a) measure soil moisture tension,
with the pressure measurements indicated by
either a mercury manometer, a vacuum
gauge, or using pressure transducers. Soil
moisture resistivity sensors (Figure 2b) mea-
sure either water content or soil moisture
tension (depending on how they are calibrat-
ed). Time domain reflectometry probes
(Figure 2c) measure water content using
induced electromagnetic currents. For vadose
zone monitoring applications, the devices are
usually placed during construction of a waste
management unit and electrical cables run to
one or more central locations for periodic
measurement.
The other commonly used method for
monitoring soil water content is to use neu-
tron or dielectric probes. These require place-
ment of access tubes, through which probes
are lowered or pulled, and allow continuous
measurement of changes in water content
along the length of the tubes.
Soil-Pore Liquid Sampling
Sampling and analysis of soil-pore liquids
can determine the type and concentration of
contaminants that may be moving through
the vadose zone. Soil-pore liquids can be col-
lected by applying either a vacuum that
exceeds the soil moisture tension, commonly
done using vacuum or pressure-vacuum
lysimeters, or by burying collectors that
intercept drain water. Figures 3a and 3b
illustrate different methods for collecting soil-
pore liquids.
Soil Gas Sampling
Soil gas sampling is a relatively easy and
inexpensive way to detect the presence or
movement of volatile contaminants and gases
associated with degradation of waste within a
waste management unit, such as carbon
dioxide and methane. Of particular concern
are gases associated with the breakdown, of
organic materials and toxic organic com-
pounds. Permanent soil gas monitoring
installations consist of a probe point placed
above the water table, a vacuum pump which
draws soil gas to the surface, and a syringe
used to extract the gas sample, as shown in
Figure 4a. Installing soil gas probes at multi-
ple levels, as shown in Figure 4b, allows
detection of downward or upward migration
of soil gases.
b. Vadose Zone Characterization
Just as the design of ground-water monitor-
ing systems requires an understanding of the
ground-water flow system, the design of
vadose zone monitoring systems requires an
understanding of the vadose zone flow system.
9-22
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Ensuring Long-Term. Protection—Monitoring Performance
Figure 2. Major Methods for In-Situ Monitoring of Soil Moisture or Matrix Potential
Mercury
Manometer
Vacuum
Gage
Pressure
Transducer
hi
D U
U
Manual
Observation
^__
-,
0
Manual
Observation
'';&P&^.t>
*
CD-
To Chart f
forConSh
Obseruati
'&$>$
Ground
Surface
Bee trades
Porous Cup
(a)
(<=)
Resistance Meter
(b)
(a) Three Types of Porous Cup Tensiometers, (b) Resistance Sensors, and (c) Time Domain
Reflectometry Probes
Sources: (a) Morrison, 1983. (b) U.S. EPA, 1993. (c) Topp and Davis, 1985, by permission.
For example, in ground-water systems,
hydraulic conductivity does not change over
time at a particular location, whereas in the
vadose zone, hydraulic conductivity changes
with soil water content and soil moisture ten-
sion. To estimate the speed with which water
will move through the vadose zone, the rela-
tionship between soil water content, soil mois-
ture tension, and hydraulic conductivity
should be measured or estimated.
Unsaturated zone numerical modeling pro-
grams, such as HYDRUS 2-D or Seep (2-D) are
designed to characterize the vadose zone.
9-23
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Ensuring Long-Term Protection—Monitoring Perft
•ormance
Figure 3. Example Methods for Collecting Soil-Pore Samples
Suction Une
Stepper
Vacuum
Sample
Flask
-Porous
Cup
(a)
(a) Vacuum Lysimeter, (b) Pressure-Vacuum Lysimeter
Source: ASTM, 1994. Copyright ASTM. Reprinted with permission.
c. Vadose Zone Monitoring
System Design
A vadose zone monitoring system com-
bined with a ground-water monitoring sys-
tem may reduce the cost of corrective mea-
sures in the event of a release. Remedial
action is usually easier and less expensive if
employed before contaminants reach the
ground-water flow system.
The design and installation of a vadose zone
monitoring system are easiest with new waste
management facilities, where soil water moni-
toring and sampling devices can be placed
below the site. Relatively recent improvements
in horizontal drilling technology, however, now
allow installation of access tubes for soil mois-
ture monitoring beneath existing facilities.
Important factors in choosing the location and
depth of monitoring points in a leak detection
network include: (1) consideration of the
potential area of downward leakage, and (2)
determination of the effective detection area of
the monitoring device.
Cullen et al. (1995) suggest an approach
to vadose zone monitoring that includes the
following:
• Identification and prioritization of critical
areas most vulnerable to contaminant
migration;
• Selection of indirect monitoring methods
that provide reasonably comprehensive
coverage and cost-effective, early warning
of contaminant migration;
9-24
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Ensuring Long-Tenn Protection.—Monitoring Performance
Figure 4. Soil Gas Sampling Systems
Flow Valve.
Vacuum Gauge
Exhaust
Gas Sample
Syringe
- Stainless Steel T Fitting
With Chromatographic Septum
Surface -^
Traffic-Rated Cover
• Cement and
Bentonite Plug
• Nyla-Ftow™ or Teflon™ Sampling Tube
Sampling Port
With Valve
Soil Gas Sampling
Probe Point (Dedicated)
\7
(a)
Concrete
Soil Gas Sampling
Probe Point
Bentonite Plug
Teflon Tubing
No. 3 Monterey Sand
(a) Gas Sampling Probe and Sample Collection Systems, (b) Typical Installation of Nested Soil
Gas Probes
Source: Reprinted with permission from Wilson, et al.. Handbook of Vadose Zone Characterization
and Monitoring, 1995. Copyright CRC Press, Boca Raton, Florida.
Selection of direct monitoring methods
that provide diagnostic confirmation of
the presence and. migration of contami-
nants;
Identification of background monitoring
points that will provide hydrogeologic
monitoring data representative of preex-
isting site conditions; and
• Identification of a cost-efficient, temporal
monitoring plan that will provide early
warning of contaminant migration in the
vadose zone.
This approach is very similar to what is
described for the basic ground-water monitor-
ing program.
9-25
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Ensuring Long-Term Protections-Monitoring Performance
automatic sampling. Manual sampling , how-
ever, can be labor intensive, expose personnel
to potentially hazardous conditions, and is
subject to human error. The advantages of
automatic sampling are the convenience it
offers, its minimum labor requirements, its
reduction of personnel exposure to hazardous
conditions, and its low risk of human error.
Unfortunately, automatic sampling is not suit-
able for all constituent types. Volatile organic
compounds (VOCs), for example, can not be
sampled automatically due to the agitation
during sample collection. This agitation can
cause the VOC constituents to completely
volatilize from the sample. Other constituents
such as fecal streptococcus, fecal coliform,
and chlorine may not be amenable to auto-
matic sampling either due to their short hold-
ing times. Since sample temperature and pH
need to be measured immediately, the option
for using automatic sampling for these para-
meters may be limited as well. Automatic
sampling also can be expensive, and does
require a certain amount of training.
Sample at the outfall point Storm-water
samples should be taken at a storm-water
point source. A "point source" is defined as
any discernible, confined, and discrete con-
veyance. The ideal sampling location is the
lowest point in a drainage area where a con-
veyance discharges, such as the discharge at
the end of a pipe or ditch. The sample point
should be easily accessible on foot and in a
location that will not cause hazardous sam-
pling conditions. Do not sample during dan-
gerous wind, lightning, flooding, or other
unsafe conditions. If these conditions are
unavoidable during an event, then the sam-
pling should be delayed until a less haz-
ardous event occurs. Preferably, the sampling
location will be located on-site, but if it is
not, obtain permission from the owner of the
property where the discharge is located.
Inaccessible discharge points, numerous small
point discharges, run-on from other property,
and infinite other scenarios may cause logisti-
cal problems with sampling locations. If the
discharge is inaccessible or not likely to be
representative of the run-off, samples may
need to be taken at a point further upstream
of the discharge pipe or at several locations to
best characterize site run-off.
Coordinate with the laboratory. Be sure to
collect adequate sample volumes to complete
all necessary analyses. When testing for cer-
tain pollutants, samples may need to be
cooled and/or otherwise preserved until ana-
lyzed to yield meaningful results. Section 3.5
of EPA's NPDES Storm Water Sampling
Guidance Document (EPA833-B-92-001) con-
tains information on proper sample handling
and preservation procedures. Submitting the
proper information to the laboratory also is
important in ensuring proper sample han-
dling by the laboratory. Proper sample docu-
mentation guidelines are outline in the sec-
tion 3.7 of the NPDES Storm Water Sampling
Guidance Document. Coordination with the
laboratory that will be performing the analy-
sis will ensure that these issues are adequately
addressed.
Follow all sampling requirements in a storm
water permit. If there are no sampling require-
ments, analyze samples for basic constituents,
such as oil and grease, pH, biochemical oxy-
gen demand, chemical oxygen demand, total
suspended solids, phosphorus, and nitrogen,
as well as any other pollutant known or sus-
pected to be present in the waste.
III. Soil Monitoring
Soil monitoring helps characterize soil
properties at a proposed land application unit
site and monitors the performance of a land
application unit. Characterizing the soil prop-
erties at a land application site helps deter-
mine application rates that maximize waste
assimilation.
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Ensuring Long-Tenn Protection—Monitoring Per/<
ormance
Table 4
Sample Method
Comparison of Manual and Automatic Sampling Techniques
Advantages
Ejisadvantages
vlanuai Grabs
Appropriate for all pollutants
Minimum equipment tequired
Labor-intensive
Environment possibly dangerous to field
personnel
May be difficult to get personnel and equip-
ment to the storm water outfall within the 3D
minute requirement
Possible human error
Manual Flow-
Weighted
Composites
(multiple
grabs)
Appropriate for all pollutants
Minimum equipment required
Labor-intensive
Environment possibly dangerous to field
personnel
Human error may have significant impact on
sample representativeness
Requires flow measurements taken during
sampling
Automatic
Grabs
Automatic Flow-
Weighted
Composites
Minimizes labor requirements
Low risk of human error
Reduced personnel exposure to
unsafe conditions
Sampling may be triggered
remotely or initiated according
to present conditions
Samples not collected for O&G may not be
representative
Automatic samplers cannot properly collect
samples for VOCs analysis
Costly if numerous sampling sites require the
purchasse of equipment
Requires equipment installation and main-
tenance
Requires operator training
May not be appropriate for pH and
temperature
May not be appropriate for parameters with
short holding times (e.g., fecal streptococcus,
fecal coliform, chlorine)
Cross-contamination of aliquot if tubing/bot-
tles not washed
Minimizes labor requirements
Low risk of human error
Reduced personnel exposure to
unsafe conditions
May eliminate the need for
manual compositing of aliquots
Sampling may be triggered
remotely or initiated according
to on-site conditions
Not acceptable for VOCs sampling
Costly if numerous sampling sites require the
purchase of equipment
Requires equipment installation and mainte-
nance, may malfunction
Requires initial operator training
Requires accurate flow measurement equip-
ment tied to sampler
Cross-contaminaton of aliquot if tubing/bot-
tles not washed
Source: U.S. EPA, 1992.
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Ensuring Long-Term Protection—Monitoring Performance
To obtain site-specific data on actual soil
conditions, sample and characterize the soil.
The number and location of samples neces-
sary for adequate soil characterization is pri-
marily a function of the variability of the soils
at a site. If the soil types occur in simple pat-
terns, a composite sample of each major type
can provide an accurate picture of the soil
characteristics. The depth to which the soil
profile is sampled, and the extent to which
each horizon is vertically subdivided, will
depend on the parameters to be analyzed, the
vertical variations in soil character, and the
objectives of the soil sampling program. Rely
on a qualified soil scientist to perform this
characterization. Poorly conducted soil sam-
pling may result in an inaccurate soil charac-
terization which could lead to improper
waste application and the unit's failure to
properly attenuate applied waste.
Sampling Location and Frequency
Prior to sampling divide the unit into uni-
form areas, then collect representative sam-
ples from each area. One recommended
approach is to divide the unit into areas no
larger than 20 acres and collect at least one
sample from each of these areas. These divi-
sions should be based upon soil type, slope,
degree of erosion, cropping history, known
crop growth differences, and any other factors
that may influence nutrient levels in the soil.
Each sample for a designated area consists
of a predetermined number of soil cores. A
soil core is an individual boring or coring at
one spot in the field. The recommended
number of cores per sample are 15-20 cores
for a surface soil sample, and 6-8 cores for a
subsurface sample. If using a soil probe, a
single core may be separated into its horizon-
tal layers to provide samples for each layer
being analyzed. For example, a single core
may be divided into three predefined layers
such as surface soil, subsurface soil, and deep
subsurface soil. For a designated area all the
individual cores are combined, according to
soil level, and mixed to provide a composite
sample for the area. From the mixed cores a
composite subsample should be taken and
analyzed. Each grab sample may be analyzed
individually, rather than combined as part of
a composite sample (see below), but compos-
ite samples generally provide reliable data for
soil characterization.
The soil core grab samples can be collected
at random or in a grid pattern. Random col-
lection generally requires the least amount of
time, but cores need to be collected from the
entire area to ensure reliable site characteriza-
tion. When performed properly, random sam-
pling will provide an accurate assessment of
average soil nutrient and constituent levels.
While the preparation required for collecting
core samples in a grid pattern can be more
costly and time consuming, it does ensure the
entire area is sampled. One advantage of grid
sampling is the ability to generate detailed
nutrient level maps for a unit. This requires
analysis of each individual grab sample from
an area, rather than compositing samples.
Analyzing each individual grab sample is time
consuming and expensive, but software and
computerized applicators are becoming avail-
able that can use this data to tailor nutrient
application to soil needs.
Soil Sampling Equipment
There are a number of soil sampling
devices available. A soil probe or tube is the
most desirable as it provides a continuous
core with minimal disturbance of the soil.
Sample cores from a soil probe can be divid-
ed by depth and provide surface, subsurface,
and deep subsurface samples from a single
boring. Soil probes are not very effective
when the soil is too wet, too dry, or frozen.
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Ensuring long-Term Protection—Monitoring Performance
The presence of gravel in the soil will also
prevent the use of a soil probe. When sam-
pling excessively wet, dry, or frozen soils, or
soils with gravel, a soil auger maybe used in
place of a soil probe. The primary drawback
of soil augers are their tendency to mix soils
from different depths during sample collec-
tion, because of this use a soil auger only
when the use of a soil probe is not possible.
A spade also may be used for surface sam-
ples, but is not effective for subsurface sam-
pling. Post-hole diggers may can be used for
collecting deeper subsurface samples, but
present the same mixing problem as soil
augers. EPA's Description and Sampling of
Contaminated Soils: A Field Pocket Guide
(EPA625-12-91-002) contains a summary of
hand-held and power-driven tube samplers.
The summary outlines the recommended
applications and limitations for each device.
Sample Collection
For initial soil characterization samples typi-
cally are taken from each distinct soil horizon
down to a depth of 4-5 feet (120-150 cm). For
example, a single core sample might provide
the following four horizon sample: surface (0-6
inches), subsurface (6-18 inches), and two
deep subsurface (18-30 inches and 30-42
inches). It is important to sample more than
just the surface layer to 'get a complete soil
characterization, and to determine if the land
application is working. Sampling subsurface
layers will show whether constituents are being
removed and assimilated as expected and not
leaching into subsurface layers or the ground-
water. As a minimum practice, sample at least
the upper soil layer (0 to 6 inches), and a
deeper soil layer (18 to 30 inches for instance).
Consult the local university extension service,
county agricultural agent, or other experts for
recommended soil sampling depths for the
specific area in which the land application unit
is located.
Once the samples have been taken they
need to be prepared for chemical analysis.
This typically is done by having the sample
air dried, ground and mixed, and then
passed through a 2 mm sieve as soon as pos-
sible after collection. If the samples are to be
analyzed for nitrate, ammonia, or pathogens,
then they should be refrigerated under moist
field conditions and analyzed as soon as pos-
sible. For more information on sample han-
dling and preparation refer to the "General
Protocol for Soil Sample Handling and
Preparation" section in EPA's Description and
Sampling of Contaminated Soils: A Field Pocket
Guide (EPA625-12-91-002). ASTM method
D-4220 Practices for Preserving and
Transporting Soil Samples also addresses prop-
er sample handling protocols.
Obtain professional assistance from quali-
fied soil scientists and laboratories to proper-
ly interpret soil samples. For more informa-
tion on obtaining representative soil samples
and submitting them for analysis, consult
federal manuals, such as EPA's Laboratory
Methods for Soil and Foliar Analysis in Long-
Term Environmental Monitoring Programs
(EPA600-R-95-077) or state guides, for
example, Nebraska's Guidelines for Soil
Sampling, G991-1000. The following ASTM
methods may also prove helpful in soil sam-
pling: D-1452 Practice for Soil Investigation
and Sampling by Auger Borings, D-1586 Test
Method for Penetration Test and Split-Barrel
Sampling of Soils, D-1587 Practice for Thin-
Walled Tube Sampling of Soils, and D-3550
Practice for Ring-Lined Barrel Sampling of Soils.
Determine baseline conditions by sam-
pling the soil before waste application begins.
Subsequent sampling will depend on land
use and any state or local soil monitoring
requirements. Once waste is being applied to
the land application unit, collect and analyze
samples at regular intervals, or after a certain
number of applications. Sample annually at a
9-30
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Ensuring Long-Term. Protection—Monitoring Perfi
ormance
minimum, or more frequently if appropriate.
Analyze samples for macronutrients,
micronutrients, and any constituents reason-
ably expected to be present in the waste. The
location and number of sampling points, fre-
quency of sampling, and constituents to be
analyzed will depend on site-specific soil,
water, plant, and waste characteristics. Local
agricultural extension services, which have
experience with designing soil sampling regi-
mens, can assist in this area. Soil monitoring,
especially when coupled with ground-water
monitoring, can detect contamination prob-
lems. Early detection allows changes to be
made to the land application process to reme-
dy the problems, and to conduct corrective
action if necessary. Finally, testing soils after
the active life of the unit is a good idea to
determine if any residues are left in die soil.
Sampling and Analytical Protocols and Quality
Assurance and Quality Control
The best designed soil monitoring program
will not provide useful data without sound
sampling and analytical protocols. Sampling
and analytical protocols are generally contam-
inant specific. A correctly designed and
implemented sampling and analysis protocol
ensures that sampling results accurately rep-
resent soil characteristics and can be com-
pared over time. The accurate representation
is achieved through statistical analysis.
Whether an established quality assurance
and quality control (QA/QC) program is
required on a federal, state, or local level, it is
a good management practice to develop and
strictly implement such a plan. The sampling
protocol should incorporate federal, state,
and local QA/QC requirements. Soil sampling
QA/QC procedures detail steps for collection
and handling of soil samples. Sample collec-
tion, preservation, shipment, storage, and
analysis should be performed in accordance
with an approved QA/QC program to ensure
data of known quality are generated.
At a minimum, include the following in
the sampling protocol:
• Data quality objectives;
• Sample collection procedures;
• Instructions for sample preservation and
handling;
• Other QA/QC procedures such as chain-
of-custody; and
• The name of the person who conducted
the sampling.
States have developed guidance documents
addressing sampling plans, protocols, and
reports. Work with the state to develop an
effective sampling protocol. Chapter 1 of EPA
SW-846 Test Methods for Evaluating Solid Waste
and ASTM Guide D-5792 provide guidance
on developing data quality objectives for
waste management activities.
Sample collection techniques should be
carefully designed to ensure sampling quality
and avoid cross-contamination of soil sam-
ples. Some constituents or parameters may be
physically or chemically unstable and should
be tested at the site rather than waiting for
shipment to a laboratory. Examples of unsta-
ble parameters include pH, redox (oxidation-
reduction) potential, dissolved oxygen, tem-
perature, and specific conductance.
Sample preservation and handling proto-
cols are designed to minimize alterations of
the chemistry of samples between the time
the sample is collected and when it is ana-
lyzed. Incorporate proper sample containers,
sample preservation, and sample transport
practices into the sampling plan. Quality
assurance and quality control, and analytical
protocols also are necessary to ensure the
validity and reliability of the sample data.
9-31
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Ensuring Long-Term Protection—Monitoring Performance
IV. Air Monitoring
The development of appropriate air moni-
toring data can be technically complex and
resource intensive. The Industrial Waste Air
Model on the CD ROM version of this Guide
provides a simple tool that relies on waste
characterization information rather than actual
air monitoring data, to evaluate risks from
VOC emissions at a unit. The air modeling tool
uses an emissions model to estimate emissions
from a waste management unit based on the
waste characterization. Review the protecting
air chapter of this guide and the supporting
background document developed for the air
model to understand the limitations of the
model and whether it is applicable to a specific
unit. If the model is not appropriate for a spe-
cific site or if it indicates that there is a prob-
lem with VOC emissions, use an alternative
(emissions) model which may be more appro-
priate for the site or consider air monitoring to
gather more site specific data.
Air monitoring could take three different
forms. Each type of monitoring provides data
to use in air emission and dispersion model-
ing. The first involves measuring emissions
from the unit using some type of collection
device or by direct measurement.
The second form of air monitoring
involves ambient air monitoring at selected
locations around the unit or site. The data is
used to monitor dispersion of airborne conta-
minants to the surrounding areas.
The third form of monitoring measures
meteorological conditions at a site. This type
of monitoring involves measurement of wind
speed, wind direction, temperature, etc.,
because other off-site meteorological informa-
tion does not adequately characterize the
weather conditions at the site. This is most
likely to occur for mountainous or hilly ter-
rain or for a site near a large body of water.
In addition, site-specific meteorological infor-
mation is generally needed whenever emis-
sions or ambient monitoring take place in
order to make proper use of all the monitor-
ing data. This information would be used for
both emission and dispersion models.
Consult with air modeling professionals
and the state and local authorities as well as
EPA's Office of Air Quality and Standards in
Research Triangle Park, NC before implement-
ing an air monitoring program or choosing
alternative emission and dispersion models.
If air monitoring is necessary to adequate-
ly characterize a site, the following references
may be helpful:
Method 204D -Volatile Organic Compounds
Emissions in Uncaptured Stream From
Temporary Total Enclosures, 40 CFR Part
51, Appendix M.
Method 204E -Volatile Organic Compounds
Emissions In Uncaptured Streams From
Building Enclosures, 40 CFR Part 51,
Appendix M.
Method 2E -Determination of Landfill Gas:
Gas Production Flow Rate, 40 CFR Part 60,
Appendix A.
Method 25C -Determination ofNonmethane
Organic Compounds (NMOC) in MSW
Landfill Gases, 40 CFR Part 60, Appendix A.
Screening Methods for Air Toxic Emission
Factors, September 1991 (EPA450-4-91-021).
Interim Final RCRA Facility Investigation (RFI)
Guidance, Volume III (EPA530-SW-89-31).
Measurement of Gaseous Emission Rates from
Land Surfaces Using an Emission Isolation
Flux Chamber: Users' Guide (EPA600-8-86-
008).
9-32
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Ensuring Long-Term. Protection—Monitoring Performance
Monitoring Performing Action Items
Consider the following for each media when developing a monitoring program for industrial waste man-
agement units:
Ground Water
D Perform site characterization, including investigation of the site's geology, hydrology, and subsur-
face hydrogeology to determine areas for ground-water monitoring; and select parameters to be
monitored based on the characteristics of the waste managed.
Q Identify qualified engineers and ground-water specialists to assist in designing and operating the
ground-water monitoring program.
D Consult with qualified professionals to identify necessary program components including the mon-
itoring well design; number, lateral and vertical placement of monitoring wells; duration and
frequency of monitoring; and appropriate sampling parameters.
D Determine the appropriate method of ground-water monitoring considering conventional well
monitoring, direct push sampling, geophysical monitoring, and vadose zone monitoring.
D Develop sample collection, preservation, storage, transport, and handling protocols tailored to data
needs, and establish quality assurance and quality control procedures to check the accuracy of the
monitoring samples.
Q Eliminate cross-contamination or background contamination of any samples by purging the wells,
using appropriate sampling equipment, and ensuring that any unstable parameters, such as pH,
dissolved oxygen, and temperature, have been tested at the site.
D Identify appropriate analytical methods and statistical approaches for the sampling data considering
parametric analysis of variance (ANOVA), tolerance intervals, prediction intervals, and control charts.
Q Determine need for assessment monitoring and abatement.
Surface Water
D Collect and analyze samples according to the site's federal or state storm-water permit if the permit
requires the facility to do so.
Q Implement a sampling program and best management practices (BMPs) to monitor surface water
quality and identify and control the contaminants in storm water run-off from a waste manage
ment unit.
9-33
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Ensuring Long-Term Protection—Monitoring Performance
Monitoring Performing Action Items (cont.)
D Perform regular maintenance inspections of surface-water protection measures.
Q Sample a representative storm and collect samples at the outfall point.
D Coordinate with a qualified laboratory to ensure the quality of sample analysis.
Q Do not collect samples under hazardous conditions.
Soil Monitoring
D Determine the number and location of samples needed to adequately characterize soil according to
the variability of the soil at a site.
D Follow established soil sampling procedures to obtain meaningful results.
D Use qualified laboratories to analyze samples.
Q Determine baseline soil conditions by sampling prior to waste application.
D Collect and analyze samples at regular intervals to detect contaminant problems.
Air Monitoring
Q Use the Industrial Waste Air Model to evaluate risks from VOC emissions.
D Use an alternative emissions model if die Industrial Waste Air Model indicates a problem with
VOC emission or is not appropriate for a site.
D Consult with an air modeling professional, state and local agencies, and EPA before implementing
an air monitoring program or choosing an alternative emissions model.
9-34
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Ensuring Lang-Term. Protection—Monitoring Perfi
'ormance
Resources
Site Characterization
American Society for Testing and Materials, 1994. ASTM Standards on Ground Water and Vadose Zone
Investigations, 2nd Edition. ASTM.
ASTM D-1452. 1980. Practice for Soil Investigation and Sampling by Auger Borings.
ASTM D-1586. 1984. Test Method for Penetration Test and Split-Barrel Sampling of Soils.
ASTM D-1587. 1983. Practice for Thin-Walled Tube Sampling of Soils.
ASTM D-3550. 1988. Practice for Ring-Lined Barrel Sampling of Soils.
ASTM D-4220. 1989. Practices for Preserving and Transporting Soil Samples.
Boulding, J.R. 1995. Practical Handbook of Soil, Vadose Zone, and Ground Water Contamination:
Assessment, Prevention and Remediation. Lewis Publishers.
CCME. 1994. Subsurface Assessment Handbook for Contaminated Sites, CCME EPC-NCSRP-48E, Canadian
Council of Ministers of the Environment.
Morrison, R.D. 1983. Groundwater Monitoring Technology. Timco Mfg. Inc.
Sara, M.N. 1994. Standard Handbook for Solid and Hazardous Waste Facility Assessments. Lewis Publishers.
Topp, G.C. and J.L. Davis. 1985. "Measurement of Soil Water Using Time-Domain Reflectometry (TDR): A
Field Evaluation," Soil Science Society of America Journal. 49:19-24.
U.S. EPA. 1993. Subsurface Characterization and Monitoring Techniques: A Desk Reference Guide. Volume I:
Solids and Ground Water, Appendices A and B. EPA625-R-93-003a.
U.S. EPA. 1993. Subsurface Characterization and Monitoring Techniques: A Desk Reference Guide. Volume II:
The Vadose Zone, Field Screening and Analytical Methods, Appendices C and D. EPA625-R-93-003b.
U.S. EPA, 1987. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using
Hydrogeologic Settings. EPA600-2-87-035.
Wilson, L.G., L.G. Everett, and SJ. Cullen (eds.). 1995. Handbook of Vadose Zone Characterization and
Monitoring. Lewis Publishers.
9-35
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Ensuring Long-Tcrm Protection—Monitoring Per/<
ormance
Resources (cent.)
Ground-Water Monitoring Well Design, Installation, and Development
Cullen, S.J. 1995. Vadose Zone Monitoring: Experiences and Trends in the United States. Ground Water
Monitoring Review 15(3):136-143.
Cullen, S.J., J.K. Kramer, andJ.R. Luellen. 1995. A Systematic Approach to Designing a Multiphase
Unsatu'rated Zone Monitoring Network. Ground Water Monitoring Review 15(3): 124-135.
Geoprobe Systems. 1996. Geoprobe Prepacked Screen Monitoring Well: Standard Operating Procedure.
Technical Bulletin No. 96-2000.
Hayes, J.P. and D.C. Tight. 1995. Applying Electrical Resistance Blocks for Unsaturated Zone Monitoring at
Arid Sites. Handbook of Vadose Zone Characterization and Monitoring. L.G. Wilson, L.G. Everett, and S.J.
Cullen (eds.). Lewis Publishers, pp. 387-399.
Kramer, J.H., S.J. Cullen, and L.G. Everett. 1992. Vadose Zone Monitoring with the Neutron Moisture
Probe. Ground Water Monitoring Review 12(3): 177-187.
Ohio Environmental Protection Agency. Technical Guidance Manual for Hydrogeologic Investigations and
Ground Water Monitoring. 1995.
Robbins, G.A. and M.M. Gemmell. 1985. Factors Requiring Resolution in Installing Vadose Zone
Monitoring Systems. Ground Water Monitoring Review 5:76-80.
U.S. EPA, 1993a. Ground-Water Monitoring: Draft Technical Guidance. EPA530-R-93-001.
U.S. EPA, 1993b. Solid Waste Disposal Facility Criteria: Technical Manual. Chapter 5. EPA530-R-93-017.
U.S. EPA. 1991. Handbook: Ground Water. Volume II: Methodology. EPA625-6-90-016b.
U.S. EPA. 1990. Handbook: Ground Water. Volume I: Ground Water and Contamination. EPA625-6-90-016a.
U.S. EPA, 1989. Handbook of Suggested Practices for the Design and Installation of Ground-Water
Monitoring Wells. EPA600-4-89-034.
9-36
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Ensuring Long-Tenn Protection—Monitoring Performance
Resources (cont.)
Sample Procedures
Benson, R.C., R.A. Glaccum, and M.R. Noel. 1984. Geophysical Techniques for Sensing Buried
Wastes and Waste Migration. EPA600-7-84-064.
Bond, WR. 1995. Case Studies of Vadose Zone Monitoring and Sampling Using Porous Suction
Cup Samplers. Handbook of Vadose Zone Characterization and Monitoring. L.G. Wilson, L.G.
Everett, and SJ. Cullen (eds.). Lewis Publishers, pp. 523-532.
Gibbons, R.D. 1990. Estimating the Precision of Ground-Water Elevation Data. Ground Water,
28, 357-360.
Minnesota Pollution Control Agency. 1995. Ground Water Sampling Guidance: Development of
Sampling Plans, Protocols and Reports.
Texas Natural Resource Conservation Commission. 1994. TNRCC Technical Guidance:
Guidelines for Preparing a Ground-Water Sampling and Analysis Plan (GWSAP).
Thomson, K.A. 1995. Case Studies of Soil Gas Sampling. Handbook of Vadose Zone
Characterization and Monitoring. L.G. Wilson, L.G. Everett, and SJ. Cullen (eds.). Lewis
Publishers, pp. 569-588.
U.S. EPA, 1995. Ground Water Sampling—A Workshop Summary. EPA600-R-94-205.
U.S. EPA, 1995. Laboratory Methods for Soil and Foliar Analysis in Long-term Environmental
Monitoring Program. EPA600-R-95-077.
U.S. EPA, 1995. Low Flow Ground-Water Sampling. EPA540-S-95-504.
U.S. EPA, 1994. Region VIII Guidance, Standard Operating Procedures for Field Sampling
Activities.
U.S. EPA 1992. NPDES Storm Water Sampling Guidance Document. EPA833-B-92-001.
U.S. EPA, 1991. Description and Sampling of Contaminated Soils: A Field Pocket Guide.
EPA625-12-91-002.
U.S. EPA, 1986. Test Methods for Evaluating Solid Waste—Physical/Chemical Methods. EPA
SW-846, 3rd edition. PB88-239-233.
9-37
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Ensuring Long-Term. Protection—Monitoring Performance
Resources (cont.)
Statistical References
Davis, C.B. and McNichols, RJ. 1987. One-Sided Intervals for at Least p of m Observations from a
Normal Population on Each of r Future Occasions. Technometrics, 29, 359-370.
Gibbons, R.D. 1994. Statistical Methods for Ground-Water Monitoring. John Wiley & Sons.
Gibbons, R.D. 1992. An Overview of Statistical Methods for Ground-Water Detection Monitoring at
Waste Disposal Facilities. In Ground-Water Contamination at Hazardous Waste Sites: Chemical Analysis.
S. Lesge and R.E. Jackson (eds.), New York: Marcel Dekker, Inc.
Gibbons, R.D., Dolan, D., Keough, H., O'Leary, K., and O'Hara, R. 1992. A Comparison of Chemical
Constituents in Leachate from Industrial Hazardous Waste and Municipal Solid Waste Landfills.
Proceedings of the Fifteenth Annual Madison Waste Conference, University of Wisconsin, Madison.
Gibbons, R.D., Gams, N.E., Jarke, F.H., and Stoub, K.P. 1992. Practical Quantitation Limits.
Chemometrics and Intelligent laboratory Systems, 12, 225-235.
Gibbons, R.D. 1991. Some Additional Nonparametric Prediction Limits for Ground-Water Monitoring
at Waste Disposal Facilities. Ground Water, 29, 729-736.
Gibbons, R.D., Jarke, F.H., and Stoub, K.P. 1991. Detection Limits: For Linear Calibration Curves with
Increasing Variance and Multiple Future Detection Decisions. Waste Testing and Quality Assurance. 3,
ASTM, SPT 1075, 377-390.
Gibbons, R.D. and Baker, J. 1991. The Properties of Various Statistical Prediction Limits. Journal of
Environmental Science and Health. A26-4, 535-553.
Gibbons, R.D. 1991. Statistical Tolerance Limits for Ground-Water Monitoring. Ground Water 29.
Gibbons, R.D. 1990. A General Statistical Procedure for Ground-Water Detection Monitoring at Waste
Disposal Facilities. Ground Water, 28, 235-243.
Gibbons, R.D., Grams, N.E., Jarke, EH., and Stoub, K.P. 1990. Practical Quantitation Limits.
Proceedings of Sixth Annual USEPA Waste Testing and Quality Assurance Symposium. Vol. 1, 126-142.
Gibbons, R.D., Jarke, F.H., and Stoub, K.P. 1989. Methods Detection Limits. Proceedings of Fifth Annual
USEPA Waste Testing and Quality Assurance Symposium. Vol. 2, 292-319.
Gibbons, R.D. 1987. Statistical Prediction Intervals for the Evaluation of Ground-Water Quality. Ground
Water, 25, 455-465.
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Ensuring Long-Term Protection—Monitoring Performance
Resources (cent)
Gibbons, R.D. 1987. Statistical Models for the Analysis of Volatile Organic Compounds in Waste
Disposal Facilities. Ground Water 25, 572-580.
Gilbert, R.O. 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand Reinhold,
New York.
Starks, T.H. 1988. Evaluation of Control Chart Methodologies for RCRA Waste Sites. U.S. EPA Technical
Report CR814342-01-3.
Patil, G.P. and Rao, C.R. eds, Elsevier. 1993. Handbook of Statistics, Vol 12: Environmental Statistics.
U.S. EPA 1993. Addendum to Interim Final Guidance Document Statistical Analysis of Ground-Water
Monitoring Data at RCRA facilities. EPA530-R-93-003.
U.S. EPA. 1989. Guidance Document on Statistical Analysis of Ground-Water Monitoring Data at RCRA
Facilities-Interim Final Guidance.
9-39
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PartV
Ensuring Long-Term Protection
Chapter 10
Taking Corrective Action
-------
Contents
I. Corrective Action Process 10~1
A.Unit Assessment 10~2
B. Unit Investigation • 10~3
1. Specific Considerations for Ground-Water Investigations 10-4
2. Specific Considerations for Soil Investigations 1°-5
3. Specific Considerations for Surface-Water Investigations 10-5
4. Specific Considerations for Air Release Investigations 10-6
C. Interim Measures r 1°"'
D. Evaluating Potential Corrective Measures 10-7
1. Meeting Cleanup Standards - 10'8
2. Evaluating Treatment Technologies • 10-10
3. Evaluating the Long- and^Short-Term Effectiveness of the Remedy 10-11
4. Evaluating the Effectiveness of Reducing or Eliminating the Source of Contamination 10-12
5. Evaluating the Ease of Implementation 10-12
6. Measuring the Degree to Which Community Concerns are Met 10-12
E, Implementing Corrective Measures 10'13
1. Institutional Controls 10-13
2. Monitoring and Site Maintenance 10-14
3. No Further Action and Site Closure 10-14
Corrective Action Action Items 10-15
Resources 1(M6
Tables:
Table 1: Factors To Consider in Conducting a Unit Assessment 10-3
Table 2: Potential Release Mechanisms for Various Unit Types 10-6
Figures:
Figure 1: Corrective Action Process 1°"2
Figure 2: Screening Process for Selecting Appropriate Treatment Technology - 10-11
-------
Ensuring Long-Term Protection—Taking Corrective Action
Taking Corrective Action
Monitor the performance of a waste management unit and take
appropriate steps to remediate any contamination. Locate and char-
acterize source of contamination. Identify and evaluate potential
corrective measures. Select and implement corrective measures to
achieve attainment of cleanup standard. Work closely with the state
and community representatives.
Effective operation of a waste man-
agement unit requires checking
the performance of the waste man-
agement system components.
When components are not operat-
ing effectively or when a problem develops,
corrective action may need to be initiated to
cleanup and protect human health and the
environment. Corrective action involves iden-
tifying exposure pathways of concern, select-
ing the best corrective measure to achieve the
This chapter will help address the
following questions:
* What steps are associated with correc-
tive action?
• What information should be collected
during investigations?
• What factors should be considered in
selecting an appropriate corrective
measure?
• What is involved in implementing the
selected remedy?
appropriate cleanup standard, and consulting
with state and community representatives
prior to beginning any extensive corrective
action program.
I. Corrective
Action Process
The purpose of a corrective action program
is to assess the nature and extent of the
releases of waste or constituents; to evaluate
unit characteristics; and to identify, evaluate,
and implement an appropriate corrective
measure or measures to protect human health
and the environment. The overall goal of any
corrective action should be to perform a tech-
nically and economically feasible risk-reduc-
tion, designed to achieve a cleanup standard
at a specified point on the facility property.
Using the ground-water pathway as an exam-
ple, corrective action for new units should
have as a goal a reduction of constituent con-
centration levels to the ground-water protec-
tion standards, that is the maximum contami-
nant levels (MCLs) or health based levels, at
the monitoring point.
10-1
-------
Ensuring Long-Term Protection—Taking Corrective Action
A corrective action program generally has
the components outlined below and in Figure
1. The detail required in each of these compo-
nents varies depending on the unit and its
complexity. Only conduct those tasks appro-
priate for a site, and coordinate with the state
during all phases of corrective action.
• Perform a unit assessment to locate the
actual or potential source(s) of the
release(s) of contaminants based on the
use of existing information.
i i
• Perform a unit investigation to character-
ize the nature and extent of contamination
from the unit and any contamination that
may be migrating beyond the facility
boundary; identify areas and populations
threatened by releases from the unit; and
determine short- and long-term threats of
releases from the unit to human health
and/or the environment.
• Identify, evaluate, and implement interim
measures, if needed. Interim measures
are short-term actions taken to protect
human health and the environment while
unit assessment or unit investigations are
being performed or before a corrective
measure is selected.
• Identify, evaluate, and implement correc-
tive measure(s) to abate the further spread
of contaminants, control the source of
contamination, and to remediate releases
from the unit.
• Design a program to monitor the mainte-
nance and performance of any interim or
final corrective measure(s) to ensure that
human health and the environment are
being protected.
A. Unit Assessment
i
Often the first activity in the corrective
action process is the unit assessment. A unit
assessment identifies potential and actual
Figure 1
Corrective Action Process
Unit Assessment
Unit Investigation
Interim Measures
Corrective Measures
Evaluation
Corrective Measures
Implementation
releases from the unit and makes preliminary
determinations about release pathways, the
need for corrective action, and interim mea-
sures. If appropriate, evaluate the possibility
of addressing multiple units as the corrective
action process proceeds. Table 1 identifies a
number of factors to consider during a unit
assessment.
As a beginning step, review all available
site information regarding unit characteristics,
waste characteristics, contaminant migration
pathways, evidence of release, and exposure
potential. Conduct
a visual site inspec-
tion of the unit to
confirm available
information and to
note any visual evi-
dence of releases. If
necessary, perform
sampling to con-
firm or disprove
suspected releases
before performing
an extensive unit
investigation.
10-2
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Ensuring Long-Term Protection—Taking Corrective Action
Table 1
Factors To Consider in Conducting a Unit Assessment
Unit/Site Chemical Migration Evidence of Release Exposure
Characteristics Characteristics Pathways Potential
Contamination
parameters
— Concentrations
— Depth and location
of contamination
Physical parameters
— Geology
— Depth to ground
water
— Flow
characteristics
— Climate
Historical
information
— History of unit
— Knowledge of
waste generation
practices
Type of waste
placed in the
unit
Volatization
parameters
Toxicological
characteristics
Physical and
chemical
properties
Chemical class
Soil sorption/
degradation
parameters
Facility's
geological
setting
Facility's
hydogeological
setting
Atmospheric
conditions
Topographic
characteristics
Prior inspection
reports
Citizen complaints
Monitoring data
Visual evidence
such as discolored
soil, seepage,
discolored surface
water or run-off
Other physical
evidence such as fish
kills, worker illness,
or odors
Sampling data
Proximity to
affected
population
Proximity to
sensitive
environments
Likelihood of
migration to
potential
receptors
Additional information on performing unit assessments can be found in RCRA Facility Assessment
Guidance (U.S. EPA 1986).
B. Unit investigation
Perform a unit investigation after a release
has been confirmed. The purpose of the
investigation is to gather enough data to fully
characterize the nature, extent, and rate of
migration of contaminants to determine and
support the selection of the appropriate
response action. Tailor unit investigations to
specific conditions and circumstances at the
unit and focus on releases and potential path-
ways. Although each medium will require
specific data and methodologies to investigate
a release, a general strategy for this investiga-
tion, consisting of two elements, can be
described:
• Collection and review of data such as
monitoring data, data which can be gath-
ered from outside information sources on
parameters affecting the release, or the
gathering of new information through
such mechanisms as aerial photography
or waste characterization.
• Formulation and implementation of field
investigations, sampling and analysis,
and/or monitoring procedures designed
10-3
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Ensuring Long-Term Protection—Taking Corrective Action
to verify suspected releases, if necessary,
and to evaluate the nature, extent, and rate
of migration of verified releases.
Detailed knowledge of the source character-
istics is valuable in identifying monitoring
constituents and indicator parameters, possible
release pathways, monitoring procedures, and
also in linking releases to a particular unit.
Waste and unit characteristics will also provide
information for determining release rates and
for determining the nature and scope of any
corrective measures which may be applied.
Refer to the characterizing waste chapter for
Guidance on Performing Unit Investigations
Additional guidance on performing unit
inspections can be found in the following
EPA documents:
• RCRA Facility Investigation Guidance
Volume 1: Development of an RFI Work
Plan and General Considerations for
RCRA Facility Investigations (U.S. EPA
1989)
• RCRA Facility Investigation Guidance
Volume 2: Soil, Ground Water, and Sub-
Surface Gas Releases (U.S. EPA 1989)
• RCRA Facility Investigation Guidance
Volume 3: Air and Surface Water
Releases (U.S. EPA 1989)
• RCRA Facility Investigation Guidance
Volume 4: Case Study Examples (U.S.
EPA 1989)
• Guidance for Conducting Remedial
Investigations and Feasibility Studies
Under CERCLA (U.S. EPA 1988) .
• Draft Practical Guide for Assessing and
Remediating Contaminated. Sites (U.S.
EPA 1989)
• Site Characterization for Subsurface
Remediation (U.S. EPA 1991)
information on how to characterize a waste.
Unit investigations may result in significant
amounts of data, including results of chemical,
physical, or biological analyses. This may
involve analyses of many constituents, in dif-
ferent media, at various sampling locations,
and at different times. Data management pro-
cedures should be established to effectively
process these data such that relevant data
descriptions, such as sample numbers, loca-
tions, procedures, and methods, are readily
accessible and accurately maintained.
1. Specific Considerations for
Ground-Water Investigations
To facilitate ground-water investigations con-
sider the following parameters:
• Ability of the waste to be dissolved or to
appear as a distinct phase;
• Degradability of the waste and its decom-
position products;
• Geologic and hydrologic factors which
affect the release pathway; and
• Regional and site-specific ground-water
flow regimes to determine the potential
magnitude of the release pathways and
possible exposure routes.
Exposure routes
of concern include
ingestion of ground
water as drinking
water and near-sur-
face flow of conta-
minated ground
water into base-
ments of residences
or other structures.
Also address the
potential for the
transfer of contam-
inants in ground
10-4
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Ensuring Long-Term Protection—Taking Corrective Action
water to other environmental media such as
discharge to surface water and volatilization to
the atmosphere.
Use an existing ground-water monitoring
program to determine the nature, extent, and
rate of contaminant release from the unit(s)
to the ground water. Investigation of a sus-
pected release may be terminated based on
results from an initial monitoring phase if
these results show that an actual release has
not, in fact, occurred. If, however, contamina-
tion is found, characterize the release through
a subsequent monitoring phase(s).
Subsequent characterization involves deter-
mining the detailed constituent composition
and concentrations and the horizontal and
vertical extent of the contaminant release, as
well as its rate of migration. This should be
accomplished through direct sampling and
analysis and, when appropriate, can be sup-
plemented by indirect means such as geo-
physical methods and modeling techniques.
2. Specific Considerations for
Soil Investigations
When performing soil investigations, consider
the following parameters:
• Ability of the waste to be dissolved by
infiltrating precipitation;
• Waste's affinity for soil particles;
• Waste's degradability and its decomposi-
tion products;
• Surface features such as topography,
erosion potential, land-use capability, and
vegetation;
• Stratigraphic/hydrologic features such as
soil profile, particle size distribution,
hydraulic conductivity, pH, porosity, and
cation exchange capacity; and
• Meteorological factors such as tempera-
ture, precipitation, run-off, and evapotran-
spiration.
Relevant physical and chemical soil proper-
ties should be measured and related to waste
properties to determine potential mobility of
the contaminants in the soil. Also, consider the
potential for transfer of contaminants in soil to
other environmental media such as overland
run-off to surface water, leaching to ground
water, and volatilization to the atmosphere. In
addition, establish whether the release involved
a localized (point) source or a non-point
source. Units that are likely sources of localized
releases to soil include container handling and
storage areas, tanks, waste piles, and bulk
chemical transfer areas. Non-point sources may
include airborne particulate contamination
originating from a land application unit and
widespread leachate seeps from a landfill.
Table 2 presents important mechanisms of
contaminant release to soils for various unit
types. This information can be used to identi-
fy areas for initial soil monitoring.
3. Specific Considerations for
Surface-Water Investigations
When conducting surface-water investiga-
tions, consider the following parameters:
• The release mechanism such as overtop-
ping of an impoundment;
10-5
-------
Ensuring Long-Tenn Protection—Taking Corrective Action
Unit Type
; Table 2
Potential Release Mechanisms for Various Unit Types
Release Mecljianism
Surface impoundment
Loading and unloading areas
Releases from overtopping
Seepage
Landfill
Migration of releases outside the unit's run-off collection and
containment systems
Migration of releases outside the containment area from loading and
unloading operations
Leakage through dikes or unlined portions to surrounding soils
Waste pile
Migration or releases outside the unit's run-off collection and
containment system
Migration of releases outside the containment area from loading and
unloading operations
Seepage through underlying soils
Land application unit
Migration of run-off outside the application area
Passage of leachate into the soil horizon
The nature of the source area such as
point or non-point;
Waste type and degradability;
Climatic factors such as history of floods;
Hydrologic factors such as stream flow
conditions; and
• Fate and transport factors such as the
ability for a contaminant to accumulate
in stream bottom sediments.
Also, address the potential for the transfer
of contaminants in surface water to other
environmental media such as soil contamina-
tion as a result of flooding of a contaminated
creek on the facility property.
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