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DRAFT
FINAL REPORT
NATIONAL SURVEY OF
SOLID WASTE
MUNICIPAL LANDFILL FACILITIES
Submitted to
The Environmental Protection Agency
Office of Solid Waste
401 M Street, S.W.
Washington, D.C 20460
(Under Contract No. 68-01-7359)
Submitted by
Westat, Inc.
1650 Research Boulevard
Rockville, Maryland 20850
September 1988
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ACKNOWLEDGMENTS
This survey was conducted by Westat, Inc. under the direction of the U.S.
Environmental Protection Agency's (EPA) Office of Policy, Planning, and Information of
the Office of Solid Waste. The EPA project manager for the survey was Jim Craig.
Doug Ruby coordinated the review and comments on the final draft.
Many individuals at EPA contributed to the survey effort Allen Geswein
and Michael Flynn of the Special Wastes Branch and Ron Burke and Cliff Rothenstein of
the Economic Analysis Staff made important contributions to the development of the survey
forms and analysis of die results of the survey.
At Westat, the Project Manager was Dr. John Michael. The efforts of
Steve Dietz, Margaret Pacious, David Hurwitz, Pat Leydig, Joan Bull, Sharon Gregory,
Gary Brown, Lori Williams, and Elizabeth Gaughan are also appreciated.
The efforts of Mark Evans and Jenny Utz of S AIC are also acknowledged
for providing technical expertise on landfill design.
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TABLE OF CONTENTS
Chapter Pjgfi
EXECUTIVE SUMMARY iv
PART I: SURVEY METHODOLOGY
1 INTRODUCTION 1-1
1.1 Overview 1-1
1.2 Congressional Mandate 1-2
2 SURVEY DESIGN 2-1
2.1 Sample Frame 2-1
2.2 Target Population 2-2
2.3 Sample Design 2-3
2.4 Preliminary Screening 2-6
2.5 Questionnaire Design 2-7
2.6 Pretest 2-7
3 DATA COLLECTION 3-1
3.1 Initial Maitout 3-1
3.2 Follow-up of Nonrespondents 3-1
4 DATA PREPARATION 4-1
4.1 General Approach 4-1
4.2 Coding and Data Entry 4-1
4.3 Editing 4-3
4.4 Confidential Business Information (CBI) 4-4
5 STATISTICAL RELIABILITY AND DATA ACCURACY 5-1
5.1 Types of Error 5-1
5.2 Sampling Error 5-1
5.3 Non-sampling Error 5-2
5.4 Maximizing Response Rates 5-3
5.5 Quality Assurance 5-4
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TABLE OF CONTENTS (continued)
PART H: SURVEY RESULTS
Chapter Page.
6 NUMBER OF LANDFILL FAOLTITES AND UNITS 6-1
6.1 Number of Landfill Facilities 6-1
6.2 Number of Landfill Units 6-1
7 QUANTITIES OF WASTE 7-1
7.1 Annual Quantity of Waste Received 7-1
7.2 Categories of Waste Received 7-2
7.3 Capacity of Landfill Facilities 7-3
8 FACILITY CHARACTERISTICS 8-1
8.1 Ownership, Permitting and Age 8-1
8.2 Proximity to Residences and Drinking Water Sources 8-2
8.3 Hydrogeology 8-3
8.4 Monitoring 8-5
9 UNIT CHARACTERISTICS 9-1
9.1 Size and Capacity 9-1
9.2 Liners 9-1
9.3 Final Covers 9-3
9.4 Leachate Collection 9-5
APPENDIX A: SUMMARY STATISTICS FOR SELECTED QUESTIONS .... A-l
List of Figures
Figures Page
3.1 Summary of the Number of Questionnaires Received Over Time 3-3
4.1 Flow Chart of Steps in Data Preparation 4-2
5.1 Data Retrieval Criteria 5-5
8.1 Distribution of Landfill Ownership 8-1
8.2 Soil Types between Bedrock and the Bottom of Landfilled Wastes 8-4
9.1 Liner Types for Active Landfill Units: Alone and in Combination
with Other Liner Types: 9-3
9.2 Final Cover Types for Active Landfill Units: Alone and in Combination
with Other Final Cover Types 9-5
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TABLE OF CONTENTS (continued)
List of Tables
Table Eigfi
2.1 Optimal stratified sampling plan for estimating the total quantity
of waste received by all facilities 2-5
3.1 Summary of contact with survey respondents 3-2
3.2 Summary of the number of questionnaires received 3-2
6.1 Total number of landfill facilities 6-1
6.2 Reported numbers of landfill units 6-2
7.1 Total annual quantity of waste received 7-1
7.2 Distribution of the average annual quantity of waste received 7-2
7.3 Total annual quantity of waste received by category 7-3
7.4 Total capacity of all municipal landfill facilities 7-4
7.5 Average capacity of a municipal landfill facility 7-4
8.1 Percentages of landfill facilities within one mile of drinking water
sources 8-2
8.2 Total number of persons in the population drinking from water
sources within one mile of a landfill facility. 8-2
8.3 Percentages of facilities with certain location characteristics 8-3
8.4 Soil types between bedrock and the bottom of landfilled wastes 8-4
8.5 Percentages of facilities that monitor ground water, gas and air 8-5
8.6 Number of wells and amount of sampling at facilities that monitor
ground water 8-5
9 . 1 Average surface area and capacity for closed, active and planned
uUMUUi Uilim •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 7 ™ 1
9.2 Liner types for closed, active and planned landfill units .................... 9-2
9.3 Liner thickness by liner type for closed, active and planned
landfill units [[[ 9-2
9.4 Final cover types for closed, active and planned landfill units ............. 9-4
9 . 5 Final cover thickness by final cover type for closed, active
and planned landfill units [[[ 9-4
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EXECUTIVE SUMMARY
This report describes the methodology and results of a national survey of
Subtitle D municipal landfill facilities. A landfill is classified as a municipal landfill if it
receives primarily household refuse and commercial waste, and is not a hazardous waste
landfill. The survey was administered for the Office of Solid Waste, United States
Environmental Protection Agency (EPA) by Westat, Inc.
The survey was conducted in response to the Hazardous and Solid Waste
Amendments (HSWA) of 1984. HSWA required that EPA (1) conduct a study to
determine whether RCRA regulations are currently adequate to protect human health and
the environment from ground-water contamination, (2) report the results of the study to
Congress, and (3) revise these regulations for facilities that receive small quantity generator
hazardous waste and household hazardous waste. Prior to this study, no comprehensive
detailed information was available on municipal landfills.
A mail questionnaire was sent to a sample of 1,250 facilities in November,
1986. Completed questionnaires were received from 1,174 facilities of which 1,102 were
determined to be eligible, that is members of the target population. Through a stratified
design, large facilities were sampled with higher probability than small facilities. Detailed
information was collected on ownership, operations, hydrogeology, waste characteristics,
landfill unit construction, monitoring systems, and operating costs. A copy of the
Questionnaire and the General Instructions mailed to each facility surveyed are given in
Appendices A and B, respectively.
The target population was comprised of all municipal landfills in the United
States and five territories. The target population was further limited to facilities that had at
least one active landfill unit as of November 1,1986. For the purposes of this survey, a
landfill unit was defined as a solid waste disposal area within a landfill facility that has the
same liner type (or no liner) throughout Closed landfill units and planned landfill units
were also surveyed, but only if they were located at a facility with at least one active landfill
unit.
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The number of active municipal landfill facilities (as of November 1986) is
estimated to be 6,034. This is considerably less than the 9,284 facilities estimated by the
Census of State and Territorial Non-Hazardous Waste Programs conducted by EPA during
the fall and winter of 1985-86. The main reasons for the reduction in the estimate are the
identification of non-municipal landfill facilities included in the previous count and recent
closings of municipal landfills.
There are an average of 2.25 landfill units at each municipal landfill facility.
Of these, an estimated 23 percent are closed, 49 percent are active, and 28 percent are
planned. By definition, each facility surveyed had to have at least one active landfill unit.
Only about 7 percent of facilities have more than 1 active landfill unit. About 25 percent of
facilities have closed units and about 29 percent have planned units.
An estimated 209 million tons of waste is received annually by municipal
landfill facilities. Of this amount, approximately 114 million tons (55%) is household and
58 million tons (28%) is commercial. A rough estimate of small quantity generator
hazardous waste received by municipal landfills is about 150 thousand tons each year.
The distribution of the quantity of waste received by a facility was observed
to be highly skewed to the right; that is, there were a relatively small number of large
facilities that accounted for a substantial portion of the total waste received. With skewed
distributions, the "typical" facility may be better represented by the median as opposed to
the mean. Whereas the average amount of waste received by a facility was about 35
thousand tons, the median value was only about 3 thousand tons. Skewness was noted for
most measures of quantity.
Several questions were posed concerning proximity to residences and
drinking water sources. About 42 percent of municipal landfill facilities are located within
one mile of private wells and about 6 percent are located within one mile of public wells.
An estimated .7 million persons use these wells for drinking water.
About 36 percent of facilities monitor ground water, 15 percent monitor
surface water, 7 percent monitor gas, and 3 percent monitor air. Leachate collection
systems were reported for an estimated 8 percent of closed, 11 percent of active and
21 percent of planned landfill units.
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Part I summarizes the survey methodology including statistical reliability
and data accuracy. Part n presents selected statistical results primarily in a tabular and
graphical form. Appendix A also presents statistical results but in a format similar to that of
the questionnaire. Some readers may prefer to go directly to Appendix A for a systematic
presentation of the results. Also statistics presented in this report are estimates and
therefore are subject to error. See Chapter S for a discussion of the various types of error
and the accuracy of the results.
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PART I
SURVEY METHODOLOGY
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1. INTRODUCTION
1.1 Overview
The Hazardous and Solid Waste Amendments (HSWA) of 1984 require that
EPA (1) conduct a study to determine whether RCRA regulations are currently adequate to
protect human health and the environment from ground-water contamination, (2) report the
results of the study to Congress, and (3) revise these regulations for facilities that receive
small quantity generator hazardous waste and household hazardous waste. In addition,
HSWA gives EPA the authority to enforce the revised regulations should the States fail to
enforce them adequately. In order to meet the Congressional mandate, EPA undertook
several studies.
One of these studies was the Municipal Landfill Survey. This survey was
of all active non-hazardous landfills that receive primarily household and commercial solid
waste in the United States and five Territories. A mail questionnaire was sent to a sample
of 1,250 facilities in November, 1986. Detailed information was collected on ownership,
operations, hydrogeology, waste characteristics, landfill unit construction, monitoring
systems, and operating costs. Statistical results are given in Part n of this report.
The data will be used by EPA to characterize the population of municipal
landfills and to assess the risks of waste management on human health and the
environment Ultimately the results of this data collection effort will be used to determine
the effectiveness of current Subtitle D guidelines and regulations, to examine the extent of
any program deficiencies, and to recommend measures to Congress that would improve the
effectiveness of the Subtitle D program. These data also will be used for regulatory impact
analyses and decision-making.
A second area where EPA will use this information is the Subtitle C
(hazardous waste) program. EPA is currently re-evaluating the list of hazardous wastes
and will use the information from this survey in assessing the risks associated with waste
management Since wastes that are not classified as hazardous may be disposed in Subtitle
D facilities, the information obtained in this survey is important to the continued
development of the Subtitle C program as well as the Subtitle D program.
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1.2 Congressional Mandate
Congress has passed a number of acts and amendments that deal with the
management of solid waste. RCRA contained the first set of guidelines to address solid
waste management practices. After the enactment of RCRA, EPA began to develop
regulations under its authority.
In 1979, under the authority of Sections 1008(a)(3) and 4004(a) of
Subtitle D of the Resource Conservation and Recovery Act (RCRA), EPA issued the
"Criteria for Classification of Solid Waste Disposal Facilities and Practices" (see 40 CFR
Part 257, hereinafter referred to as "Criteria"). These Criteria addressed which solid waste
disposal facilities and practices pose a reasonable probability of adverse effects on health or
the environment. The Criteria are used by States to classify solid waste disposal facilities
as either open dumps or sanitary landfills. Facilities that violate any of the provisions of
the Criteria are deemed "open dumps." A ban on open dumps is enforced by either the
States or citizen suits. EPA has no direct enforcement authority for the current Criteria.
Instead, the Federal role is limited to the development of the Criteria and to technical and
financial assistance.
In 1979, EPA also issued guidelines for the development of State Solid
Waste Management Plans (see 40 CFR Part 256). These guidelines require that States
seeking EPA Subtitle D grant funds have the authority to prohibit, close, and upgrade open
dumps. These grant funds were available from 1977 to 1981. Aside from approval of
State plans and the disbursement of grant funds, EPA had no direct implementation
authority for the Criteria. Subtitle D was, and still is, basically a State-administered
program.
Subtitle D funding of State activities was terminated after 1981. Since then
the focus of EPA's efforts has been on Subtitle C (hazardous waste) efforts. As a result of
reduced involvement in Subtitle D activities, EPA has limited current information on the
status of State non-hazardous waste programs and on the facilities themselves.
The Hazardous and Solid Waste Amendments (HSWA) of 1984, signed
into law on November 8,1984, states, in part, the following:
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• "The Administrator shall conduct a study of the extent to which the
guidelines and criteria under this Act...are adequate to protect human
health and the environment from groundwater contamination."
• "..., the Administrator shall submit a report to the Congress setting
forth the results of the study required under this section...."
• "..., the Administrator shall promulgate revisions of the Criteria
promulgated under paragraph (1) of Section 4004(2) and under
Section 1008(a)(3) for facilities that may receive hazardous
household wastes or hazardous wastes from small quantity
generators under Section 7001(d)."
And HSWA gives EPA the authority to enforce the revised Criteria should the States fail to
enforce them adequately.
As a first step in meeting the Congressional mandate, EPA collected
information on the number and basic characteristics of Subtitle D facilities in a census of
U.S. State and Territorial governments1. (Hereafter, we will refer to this survey as the
Subtitle D Census.) The purposes of the study were to evaluate the status of Subtitle D
programs (organization, resources, enforcement, etc.) and to generate basic aggregated
estimates on the numbers and types of Subtitle D facilities. Based on this information,
EPA estimated that in 1984 there were a total of 227,127 Subtitle D facilities located
throughout the 50 States and five Territories2. Of these facilities, about 9,000 were thought
to be active residential or commercial (municipal) landfill facilities -- a key subset of
Subtitle D facilities, because it is likely that they receive household hazardous waste and
small quantity generator hazardous waste. Based on this survey, EPA now estimates that
about one third of these sites are either closed or do not fit the definition of a Municipal
Landfill. The estimate of the number of active municipal landfill facilities as of
November 1986 is 6,034.
To meet the Congressional mandates, EPA is undertaking several studies to:
(1) assess the impacts of non-hazardous municipal waste and industrial waste landfills,
surface impoundments, and land application units on surface water, ground water, and air,
(2) assess the implementation of the non-hazardous waste program by the States; and
(3) make recommendations concerning possible changes to the Federal and State Subtitle D
1 Census of Slate and Territorial Non-Hs^flrdoiis Waste Programs prepared by Westat, Inc. for the U.S.
Environmental Protection Agency, Contract No. 68-01-7047. April 1986.
territories were the Commonwealth of Puerto Rico, the Virgin Islands, Guam. American Samoa, and the
Commonwealth of the Northern Marianas. The District of Columbia reported no Subtitle D facilities.
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non-hazardous waste permitting and enforcement programs. The EPA Offices primarily
responsible for this study are the Office of Solid Waste and the Office of Water.
Specifically, the Municipal Landfill survey is designed to gather information
in each of the following areas from each individual municipal landfill:
• Landfill owner, operator, and permitting status;
• Facility jurisdiction, size, and operations;
• Hydrogeologic and water source information;
• Waste characteristics;
• Individual landfill unit information, e.g., liners, covers, leachate
systems, and runoff systems;
• Monitoring systems; and
• Landfill operating costs and revenues.
EPA asked each State to provide a list of municipal landfills as part of the Subtitle D
Census. EPA compiled these lists and used them as the initial population universe for the
Municipal Landfill Survey data collection effort.
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2. SURVEY DESIGN
2.1 Sample Frame
The Subtitle D Census of 1986 conducted by EPA was the first attempt to
compile a comprehensive list of Municipal Landfills in the United States and Territories.
The Subtitle D Survey instrument itself gave the following definitions:
• Municipal Waste Landfill - A Landfill that primarily receives
household refuse and commercial waste. It may also receive a
limited amount of other types of Subtitle D wastes, such as
municipal sewage sludge and industrial wastes.
• Landfill - A part of an establishment at which waste is placed...
• Establishment - A single physical location where business is
conducted or where services or industrial operations are performed
by a municipality, corporation, or other public or private entity...
Question D2 of the Subtitle D Survey asked each respondent to estimate the
number of active Municipal Waste Landfills. This provided a national estimate of 9,284
such landfills. Question F7 asked each respondent to attach a list of all Subtitle D facilities.
These lists were keyed into a computer. The resulting data base of Subtitle D facilities was
the starting point for the development of the sample frame for the Municipal Landfill
Survey. (Hereafter, this data base will be referred to as the Subtitle D Census data base.)
An extensive and systematic cleaning and data retrieval effort was
performed on the Subtitle D Census data base in 1986 prior to the selection of a sample.
The lists of facilities provided by the states and territories differed in format, accuracy,
temporal scope, and completeness. Respondents were contacted where key data were
missing or suspect For each respondent, the total number of Municipal Landfill facilities
provided on the list submitted in response to the Subtitle D Survey was compared to the
number given in the response to Question D2. Clarification was sought where there was a
discrepancy. The reasons given for discrepancies fell into three general categories:
• Temporal differences. The Subtitle D Survey was conducted in
the fall and winter of 1985-1986. The lists provided were
sometimes dated much earlier. There were numerous instances of
facilities on the list that had closed and therefore were not included
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in the counts given in response to the Subtitle D Survey. There
were fewer instances of openings.
• Definition. Some lists contained unattended sites. There were
numerous instances where the site was not at a location where
"business is conducted or where services or industrial operations are
performed by a municipality, corporation, or other public or private
entity."
• Errors. Counts by some states were estimates or judgement calls.
Some states were unable to reconstruct the counts reported in the
Subtitle D Survey, and still others were unable to reconstruct the
lists. One state included closed facilities. Another state included
Demolition Debris Landfills in the count of Municipal Landfills.
Multiple follow-up calls were made to most states/territories. A number of
states resubmitted their lists. One submitted a list for the first time. Our data retrieval effort
continued from March until October, 1986, by which time all major differences were
satisfactorily resolved. The revised sample frame consisted of 8,343 facilities.
Supplemental data collection was also done in conjunction with the data
cleaning and data retrieval effort. Each Subtitle D Survey respondent was asked to identify
Municipal Landfills that received over 500 tons of waste per day. (Such sites will be
referred to below as "large" sites.) This necessitated contacting almost all states as few had
provided size information on the submitted lists of facilities. The purpose of this data
collection effort was to sample "large" and "small" facilities separately. The stratified
random sample design is described in Section 2.3 below.
2.2 Target Population
The definition of a Municipal Landfill facility was the same as the definition
used in the Subtitle D Census. In particular, a facility had to have landfills that received
primarily household and commercial waste, not be classified as a Subtitle C facility, and be
at a location where business was conducted or where services or industrial operations were
performed by a municipality, corporation, or other public or private entity. "Primarily" is
interpreted to mean at least SO percent. Thus at least SO percent of the waste received must
be household and/or commercial waste. Household waste is waste that typically comes
from residential units. Commercial waste comes from office buildings, restaurants, and
other retail and wholesale businesses.
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The target population was limited to facilities that had at least one active
landfill unit as of November 1,1986. A landfill unit was defined as follows:
• Landfill Unit: a discrete area within a landfill facility used for
disposing solid wastes. A landfill unit has the same liner type (or no
liner) throughout and is bounded either by land on which no waste
is placed or by another unit with a different liner type. A single
landfill unit may have adjacent sections, but each will have the same
liner type.
Closed landfill units and planned landfill units were also surveyed, but only
if they were at a facility with at least one active landfill unit. EPA determined that a survey
of active facilities would achieve all the objectives set down by Congress while avoiding
the difficulties associated with including closed and planned facilities in the target
population. It would have been very difficult to identify all closed facilities and to find
parties who would acknowledge responsibility for these sites. Planned facilities would
also be more difficult to identify and the anticipated characteristics of planned facilities,
when available, would be subject to more uncertainty and potential bias.
In summary, the target population was defined as follows:
• Target Population: All non-hazardous solid waste landfills in
the 50 states, District of Columbia and five territories (1) that had at
least one active (or temporarily inactive) landfill unit on November
1, 1986; (2) that received primarily household and commercial
waste; and (3) were part of an establishment where business was
conducted or where services or industrial operations were performed
by a municipality, corporation, or other public or private entity.
2.3 Sample Design
The sample design selected was a stratified random sample of facilities. The
stratification was done on the basis of the estimated quantity of waste received per day.
Stratification in this fashion will result in much improved national estimates of the
quantities of waste with only a small loss of efficiency when estimating proportions.
Specifically, EPA anticipated that for estimating quantities the stratified design would be up
to two and a half times more efficient than a simple random sample. For estimating
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proportions, the loss in efficiency of the stratified design would be no more than about
five percent.
On the basis of the estimated quantity of waste received per day, the sample
frame was broken down into two strata. Stratum 1 consisted of 406 "large" facilities on the
sample frame, or those facilities that were estimated to receive at least 500 tons of waste per
day. Stratum 2 consisted of the remaining 7,937 "small" sites, or those that were believed
to receive less than 500 tons of waste per day. Further stratification was impractical
because most states/territories had limited knowledge of the operating characteristics of
individual facilities.
In order to receive 1,000 useable questionnaires, we estimated that 1,250
would have to be mailed We expected to lose about 20 percent due to non-response and
facilities being out of scope, i.e., not fitting the definition of a Municipal Landfill facility.
Table 2.1 gives the optimal stratified sampling plan for a sample size of
1,000. It is optimal in the sense that, for a fixed total sample size of 1,000, such an
allocation minimizes the variance of the estimate of total quantity of waste received. This
optimum plan was calculated using Neyman allocation which requires knowledge of the
mean and standard deviation of the quantity to be estimated within each stratum. These
parameters were estimated using the counts of facilities estimated to receive less than 30,
30-500, and at least 500 tons of waste per day (obtained from the Subtitle D State Census)
and then fitting to them a distribution with a shape similar to the shape of the distribution of
the population of cities in the United States.
The optimal allocation for a sample size of 1,000 completed questionnaires
was 200 (52%) of the estimated 382 "large" facilities and 800 (13%) of the estimated 6,147
"small" facilities. Thus a "large" site was about four times as likely as a "small" site to be
sampled.
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Table 2.1 Optimal stratified sampling plan for estimating the total quantity of waste
received by all facilities
Stratum
"Large"
"Small"
Total
Optimal
allocation
ofeligibles
in sample
200
800
1,000
Number
in Frame
406
7,937
8,343
Preliminary
estimate of
eligibles
in Frame
382
6,147
6,529
Sampling
fraction*
.52
.13
.15
"'Sampling Fraction = Eligibles in Sample / Eligibles in Frame.
The computation of the optimal allocation required knowledge of the
numbers in each strata in the target population, or universe. The number in the universe is
not the same as the number in the sample frame because the latter contains a considerable
number of mis-classified sites. Therefore, a preliminary sample was taken and, through a
screening procedure described below, the number of eligible facilities in each strata was
estimated. These preliminary estimates are shown in the above table and formed the basis
of the computations for optimal allocation. Note that a disproportionately higher percentage
of "small" sites were mis-classified as being in the universe. This result is not surprising
since the larger sites are better known and classification was therefore more reliable.
The sample size of 1,000 useable questionnaires was selected using the
following procedure. Optimal variances for percentages and quantities were approximated
using Neyman allocation for a number of different sample sizes. We then selected a sample
size of 1,000 for the study because it held the respondent burden and cost to a minimum
while still achieving acceptable levels of accuracy.
Note that the above discussion refers to the the number of completed
questionnaires received from eligible facilities. In order to achieve this goal, a larger
number of questionnaires were actually mailed, even after most of the ineligibles had been
eliminated through the preliminary screening described below. Losses due to non-response
and ineligibility were estimated to be as high as 20 percent. Thus the initial mailout was to
1,250 facilities. A total of 1,176 questionnaires were received of which 1,102 were from
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eligible facilities. This exceeded the goal of 1,000 completed questionnaires from eligible
facilities.
2.4 Preliminary Screening
A stratified random sample of 1,701 facilities was drawn from the sample
frame. These 1,701 facilities constituted the pool from which the final sample would be
selected. An attempt was made to contact each of these facilities in order to accomplish the
following:
• To verify that the facility was indeed an active municipal landfill;
• To obtain the name and address of the person to whom the
questionnaire should be sent;
• To alert that person to the survey so that he/she would be more
likely to complete and return the mail questionnaire; and
• To obtain preliminary estimates of the percentage of facilities that
were out of scope in order to determine optimal allocation and the
size of the mailout.
In some eases, a contact person and telephone number had been provided
by the state in response to the State Subtitle D census. In others, directory assistance was
called in order to obtain an initial contact number.
At this preliminary screening stage, 336 sites were identified that didn't
appear to fit the definition of a Municipal Landfill facility. For these sites, there was no
evidence that business was being conducted or services provided, and no one could be
located who would acknowledge responsibility for the site. These so-called "promiscuous"
sites were classified as ineligible.
Screening calls were conducted to determine names and addresses. Only
eight facilities could not be contacted after repeated attempts. There were seven instances
or duplication where a facility was listed twice. A total of 336 facilities were classified as
ineligible. This left 1,350 eligible facilities for the mailout, of which 1,250 were selected.
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2.5 Questionnaire Design
The survey instrument was developed over several months by EPA staff
responsible for regulation development with review by technical experts. Because detailed
instructions were required for questions of a technical nature, we decided to design a
separate booklet of General Instructions. In order to provide technical assistance to
respondents, the General Instructions listed a toll-free telephone number to call.
2.6 Pretest
There were two major differences between the pretest and the actual survey.
The first was that the pretest required initial contact with respondents to determine if they
were willing to participate in the pretest The other difference was that after completing the
pretest questionnaire, EPA followed up with extensive discussions with each respondent in
order to identify any potential problems in completing the questionnaire. The major
emphasis in these discussions was on question clarity, format, and ease of response.
EPA contacted nine municipal landfill facilities by phone in early August
1986, and asked them to participate in the pretest. In selecting sites, attention was first
focused on selecting diverse facilities in the neighboring states of Maryland, Pennsylvania,
Virginia, and West Virginia. Their close proximity to EPA offices in Washington, D.C.
would facilitate site visits, should such visits become necessary. (As it turned out, none
were visited.) EPA selected nine facilities that represented different states, different types
of ownership (public and private), different sizes (an estimated 4 tons to 4500 tons received
per day), and different operating characteristics (presence or absence of monitoring and/or
leachate collection systems).
Each of the nine selected facilities was mailed Questionnaire and General
Instruction booklets on August 14. A cover letter gave a background summary and
explained the purpose of the pilot study. Shortly thereafter, each facility was contacted to
ensure that the materials had been received and that work on the Questionnaire was planned
or in progress. Approximately two and four weeks later, follow-up calls were made to
nonrespondents.
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Eight of the nine facilities returned completed questionnaires. One facility
decided not to participate in the pretest on advice of legal counsel because it did not have a
permit and was then in litigation with the state. EPA contacted each of the eight
participating facilities and asked the following general questions:
• Were there parts of the General Instructions that were difficult to
understand?
• Can you think of better ways to work the General Instructions?
• Were there any questions that you had difficulty understanding?
• Were there any questions that you had difficulty answering?
• Can you think of better ways to word any questions?
• How long did it take you to complete the questionnaire?
The pattern observed was that the data were relatively complete for large
facilities compared to small facilities, particularly regarding design capacity and
hydrogeologic data. The complexity of certain questions tended to be a problem only for
the smaller less sophisticated sites. Respondents felt that additional definitions of terms
would help, but only to a limited degree. Most of the missing data occurred because the
respondent didn't know the answer, not because he didn't understand the question.
Instances of failure to complete a question, or failure to follow instructions, appeared
unrelated to the length of the questionnaire. The average length of time to complete the
questionnaire was about two hours, as predicted.
As a result of the pretest, only minor changes were made in the survey
instrument. These included the rewording of some questions and the addition of several
others.
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3. DATA COLLECTION
3.1 Initial Mailout
The initial mailout of 1,250 questionnaires was conducted in mid-
November, 1986. Each Questionnaire was accompanied with a set of General Instructions,
a cover letter from EPA which explained the purpose of the survey, and a postage-paid
return envelope. Each package was sent via certified mail.
3.2 Follow-up of Nonrespondents
The first follow-up action took place approximately two weeks after the
initial mailout. In early December, a confirmation letter from EPA was mailed to each
facility surveyed. The letter confirmed the mailing of the questionnaire package and urged
to facility manager to complete and return the questionnaire as soon as possible.
Two telephone prompts were conducted later in an attempt to increase the
response rate and the quality of the responses. In mid-December, telephone calls were
made to 819 facilities that had neither returned the completed questionnaire nor contacted
the Questionnaire Assistance Center. The caller reminded the respondent of the importance
of the survey and asked for a date by which the questionnaire would be completed and
returned. If the respondent needed technical assistance, the caller arranged for a return call
by a technical specialist. In late January, 1987, a second series of telephone prompts were
made to 345 nonrespondents.
Finally, in April, a package was sent from EPA to each of the 167
remaining nonrespondents. Each package contained a letter from EPA urging cooperation,
a copy of the letter that was included in the original mailing in November 1986, and another
copy of the Questionnaire and General Instructions. At that time, 24 of the 167
nonrespondents had expressed their intention not to participate in the survey. These 24 so-
called "refusals" were sent a different version of the cover letter. By the end of the data
collection effort, all but 7 of the initial 24 "refusals" had been "convened" by the Data
Retrieval team and returned completed questionnaires.
-------
A summary of the contact with survey respondents is given in Table 3.1.
A summary of the number of questionnaires received over time is shown in Figure 3.1.
The primary data collection effort ended on June 30 when the last questionnaire was
received.
A total of 1,176 questionnaires were either received by mail or completed
over the phone for an overall response rate of 94 percent. Of the 74 nonrespondents, 7
were classified as "refusals" who informed a telephone interviewer that they would not
complete and return the questionnaire. Of the 1,176 respondents, 74 (coincidentally) were
determined to be ineligible. This left a total of 1,102 eligibles which exceed our goal of
1,000 These results are summarized in Table 3.2 below.
Table 3.1 Summary of contact with survey respondents
Type of contact
Initial mailout
Confirmation letter
First telephone prompt
Second telephone prompt
Nonrespondent letter
Number contacted
1,250
1,250
819
345
167
Date of contact
November 1986
December 1986
December 1986
January 1987
April 1987
Table 3.2 Summary of the number of questionnaires received
Stratum
"Large"
"Small"
Total
Total
mailed
250
1,000
1,250
Total
received
238
938
1,176
Response
rate
95.2%
93.8
94.1
Eligibles
received
227
875
1,102
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Figure 3.1
Summary of the Number of Questionnaires Received Over Time
Number of
Questionnaire*
Received
per Week
200-
150-
16 20 24 28 32 36
k Week <
1250 Questionniares Mailed
1250 Confirmation Letters —'
819 Telephone Prompts —'
345 Telephone Prompts
167 Letters to Non-Respondents
End of Primary Data Collection
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4. DATA PREPARATION
4.1 General Approach
The major steps in the data preparation process are shown in Figure 4.1. At
the center of the activity was the Coding operation. The Coding staff received data in the
form of incoming questionnaires, supplementary data from the Data Retrieval staff, and
computer printouts that summarized edit checks. The Coding staff also forwarded data to
Data Retrieval and Key Entry for processing. The data preparation manager and the receipt
control operation were also co-located with Coding. The data preparation manager
monitored the data flow in Coding, Data Retrieval, and Key Entry. In addition, the data
preparation manager supervised the receipt control system which tracked each questionnaire
from mailout through the data cleaning stage.
Some questionnaires cycled through the the Error Checking stage several
times. An effort was made to limit to one the number of times a questionnaire was passed
to Data Retrieval because of the cost of initial contact and the burden of multiple calls on the
respondent.
4.2 Coding and Data Entry
The term coding is usually used to describe the process of transcribing
responses written on the questionnaire into a consistent form suitable for direct Key Entry.
For some data fields, no transcription was necessary. For others the response was circled,
abbreviated or coded with a special value. Coders also prepared the Data Retrieval sheets,
entered new data from Data Retrieval on questionnaires and data update sheets, collated
related responses in order to reconcile apparent inconsistencies, and interpreted computer-
generated edits.
A team of eight coders received special training by the data preparation manager. A key
reference document was the code book. The code book names all the variables, defines
codes, indicates skip patterns, and gives acceptable values and ranges for each variable.
The data preparation manager along with certain coders also functioned in a quality control
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Figure 4.1
Flow Chart of Steps in Data Preparation
Incoming
Questionnaires
Clean Dam
-------
capacity by checking the work of others coders. All coding was 100 percent verified
before it was passed to Key Entry.
The first time a questionnaire was coded, it was sent to Key Entry in its
entirety. All keyed data were 100 percent verified. Updates were made by running special
update programs on the computerized data.
4.3 Editing
The editing of the data consisted of a series of five edits: (1) scan edits,
(2) standard machine edits, (3) custom logic edits, (4) mass edits and (5) special edits.
Scan edits were performed by Coding when the questionnaire was initially
coded. Often apparent errors were rectified by reference to other related responses. In
other cases, rules were applied to convert a response into an acceptable value.
Standard machine edits were computerized edits that checked to see that
ranges and codes specified in the code book were adhered to for each field. This included
skip patterns which specified conditions under which fields should be left blank.
Custom logic edits primarily checked across fields for consistency.
Whereas the standard machine edit was derived automatically from the code book and
looked primarily within fields, custom logic edits required logical consideration across
fields.
Mass edits procedures apply descriptive statistics to collections of cases.
Usually these descriptive statistics took the form of frequency distributions, cross-
tabulations, or scattergrams. Descriptive statistics helped to identify errors that caused a
value to stand out from the rest. Frequency distributions were generated and studied for
every field. Distributions across fields were also examined for consistency and
reasonableness.
-------
Special edits were conducted because of the significance of certain
questions. These included the following:
• Any facility that reported being out of scope (Q1.2) was contacted
by telephone and its status was verified.
• The reported average annual quantity of waste received was
compared to the stratification variable and large differences were
verified by telephone.
• Because of a typographical error in Question 4.3, responses to this
question were either verified by telephone when the respondent was
contacted for data retrieval or dropped from the data base.
4.4 Confidential Business Information (CBI)
In the cover letter that accompanied each questionnaire, EPA explained why
the data were being collected, how the data would be used, and identified the contractors
and subcontractors to whom the data would be transmitted for regulatory development.
Each respondent was apprised of his/her right to assert a claim of CBI covering all or part
of the information furnished to EPA and was instructed as to how to make such a claim.
Questionnaires declared to be CBI were and continue to be handled in accordance with 40
CFR Part 2.
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5. STATISTICAL RELIABILITY AND DATA ACCURACY
5.1 Types of Error
It is important to keep in mind that the estimates provided in this report are
subject to errors of various kinds. Errors in sample survey estimates can usually be
classified into two major categories: sampling errors and non-sampling errors. Sampling
errors result from the fact that estimates are based on only a sample of the population and
not the entire population. Nonsampling errors include all other sources of error. Each of
these major types of error are discussed below.
5.2 Sampling Error
In order to quantify the variability of the estimates presented in this report,
the standard errors of the estimates were also estimated. The standard error is a measure of
the variability of an estimate due to sampling error. On the average, estimates will be
within one standard error of the true population parameters about 68 percent of the time,
and within two standard errors of the true population parameters about 95 percent of the
tune.
Indication of the variability of estimates are given in two ways in this report.
In Part n, standard errors and corresponding 95 percent confidence intervals are given for
selected estimates. A 95 percent confidence interval is constructed by adding and
subtracting 1.96 standard errors from estimates. A 95 percent confidence interval will
contain the true parameter about 95 percent of the time. In the appendix, a second method
is used to caution the reader of high variability. One or two asterisks (*) following a
statistic are used to indicate when the estimated standard error is greater than 25 percent or
50 percent, respectively, of the estimate itself. One asterisk indicates high relative
variability, and two asterisks indicate very high relative variability. In the latter case, a
95 percent confidence interval would contain values as low as 0 and as high as twice the
estimate.
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5.3 Non-sampling Error
Sources of error in a survey other than sampling error are referred to as
non-sampling errors. Non-sampling errors by the respondent include mistakes in
interpreting questions, researching answers, and writing down responses. Non-sampling
errors in the processing stage include errors in coding, key entry, programming, and
reporting. Nonresponse bias errors occur if nonrespondents differ systematically from
respondents. The incompleteness of the sample frame can also result in biased estimates of
averages and percents and in underestimates of population totals.
Although respondent and processing errors probably occurred during the
course of this survey, there is no evidence to suggest that they introduced significant
amounts of bias or error into the survey results. Intensive quality control efforts are
summarized below in Section 5.5 that were utilized to minimize nonsampling errors.
The possible incompleteness of the sample frame is always a possibility in a
survey designed around a frame compiled from lists. Whereas the percentage of ineligibles
on the sample frame can be estimated and adjusted for using the survey results, it is
difficult to estimate the number of eligible facilities that do not appear on the sample frame.
The quality of the frame used in this survey depends on the quality of the data provided by
the states. The process of contacting the states in order to reconcile the aggregate numbers
reported on the Subtitle D Census afforded EPA the opportunity to assess the quality of the
data on a state-by-state basis. While some omissions were discovered for some states,
these errors were not substantial or widespread. The effect of any incompleteness in the
sample frame would be to deflate estimates of totals for the population.
Seven instances of duplicate pairs of entries were discovered in the
screening sample. Duplicates were eliminated and the sample weights on the retained
members of the pairs were halved. Other yet undiscovered duplicates may exist, although
they are estimated to comprise no more than .5 percent of the sample frame. The effect of
any such duplicates would be to inflate estimates of totals for the population.
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5.4 Maximizing Response Rates
A major reason for maximizing the number of responses to a question is that
one can never be sure if nonrespondents have the same characteristics as respondents. If
nonrespondents are systematically different from respondents, estimates based on the
survey data can be biased. The degree of bias depends on the extent to which
nonrespondents differ from respondents and the response rate.
Participation in the survey was mandatory under Section 3007(a) of RCRA.
The mandatory nature of the survey contributed to the high response rates achieved. As
given earlier in Table 3.2, the response rate for this survey was 94.1 percent. Given the
nature of most municipal landfills ~ small operations run by a town official with little
technical background and many other responsibilities, EPA chose not to pursue
enforcement against nonrespondents.
EPA also used a number of measures to maximize the number of facilities
that returned completed questionnaires. Some of the measures are discussed in
Section 3.2. EPA also utilized a number of diverse techniques in order to maximize the
item response rate. The key to high initial item response rates was careful questionnaire
design, making sure that each question was easy to understand and easy to answer.
Closed-ended questions were used whenever possible; and skip patterns were used
extensively in order to reduce the burden on the respondents and speed them through the
questionnaire. The General Instructions contained a set of definitions of important terms,
a diagram of a typical landfill facility, and gave examples of each major question/response
format.
For respondents who had questions or problems, the toll-free telephone
number of the Questionnaire Assistance Center was given in both the General Instructions
and the cover letter. Incoming calls were channeled to a technical specialist who was very
familiar with the questionnaire. In addition, telephone numbers for the EPA Project
Manager, Jim Craig, and the RCRA-Superfund Hotline were given in the cover letter.
A second way in which item response rates were increased was through the
data retrieval process - the process of re-contacting the respondent by telephone in order to
fill data gaps and resolve inconsistencies. The degree of data retrieval that was done for a
particular item depended on how the item was answered and the importance of the item. In
-------
some cases the respondent left the space for the answer "blank" and in other cases wrote
"unknown" next to it. For some items data retrieval was done on "blanks" but not
"unknowns." Certain critical items were deemed "trigger" items in that a data gap would
cause a data retrieval call to be made. For other items, data retrieval was done on the item
only if some other more important item triggered a data retrieval call For still others items,
no data retrieval was attempted, even if a data retrieval contact was made. Figure 5.1 gives
the degree of data retrieval done for each item in the questionnaire.
The item response rate varied with the technical level of the question. Most
questions required only general knowledge of the facility and their response rates were
typically above 90 percent. But for some technical questions the response rate was low.
For example only about 261 or 24 percent gave an answer to Question 3.7c which asked
for the hydraulic gradient of the uppermost aquifer at the facility. The response rates to
questions about closed and planned landfill units were also low - only about 45 percent
With these exception, the response rates were typically quite high - over 90 percent.
5.5 Quality Assurance
Quality assurance procedures touched every aspect of the study, from the
coding of each data item to estimation of the variances of estimates. Below we summarize
quality assurance procedures, many of which are discussed in more detail in other parts of
this report
• The Questionnaire and General Instructions were carefully designed
and went through numerous revisions;
• The Questionnaire and General Instructions were reviewed by
numerous EPA staff as well as representative from the National
Solid Waste Management Association (NSWMA), the American
Public Works Administration (APWA), Governmental Refuse
Collection and Disposal Association (GRCDA), and trade
associations;
• A pretest was conducted with extensive follow-up discussions (see
Section 2.6);
• Efforts were made to maximize the response rate (see Section 5.4);
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Q
U
E
S
T
I
O
N
Figure 5.1
Data Retrieval Criteria
SECTION
12345CAP67
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
b
bu
b
b
b
b
b
b
b
bu
bu
bu
bu
bu
b
b
b
bu
bu
bu
bu
bu
X
X
b
b
X
X
b
X
X
b
b
b
X
X
b
b
b
b
b
b
b
b
b
b
•
bu
b
b
b
X
b
b
b
b
bu
bu
bu
bu
b
b
b
b
b
b
X
b
b
b
X
b
b
b
b
b
b
bu
bu
bu
bu
b
b
bu
b
b
b
b
X
b
b
b
X
b
b
b
b
b
b
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
i
b
b
bu
b
X
b
X
X
b
b
b
X
b
b
b
b
b
b
b
The following table entries indicate when data retrieval was performed, given that
a call was made:
b: when answer is blank;
u: when unknown is written in as an answer,
bu: when answer is blank or unknown;
x: no data retrieval
Table entries in bold print indicate problems that triggered a data retrieval call.
-------
Thorough training was given to coders (see Section 4.2) and data
retrieval specialists;
Coding and key entry work was 100 percent verified (see
Section 4.2);
Extensive error checking was conducted which included scan edits,
standard machine edits, custom logic edits, mass edits, and other
special edits (see Section 4.3);
Estimates were computed manually to double-check the logic of
computer programs; and
The data were reviewed independently by EPA over a period of
several months prior to the release of this report.
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PART II
SURVEY RESULTS
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6. NUMBERS OF LANDFILL FACILITIES AND UNITS
6.1
Number of Landfill Facilities
Based on this survey, there were an estimated 6,034 active Municipal
Landfill facilities in the United States and territories in November, 1986. Table 6.1 shows
this result and presents the estimated standard error of the estimate along with the
corresponding 95 percent confidence interval. With 95 percent confidence, we can say that
the total number of landfill facilities ranges from 5,882 to 6,186 facilities. (See Chapter 5
for a discussion of sampling and nonsampling error, standard error and confidence
intervals.)
Table 6.1 Total number of landfill facilities
Active municipal landfills
Total number
in population
6,034
Standard
error
77.5
95%
Confidence
interval
5,882 - 6,186
6.2
Number of Landfill Units
A landfill unit is defined as a discrete area within a landfill facility that is
used for disposing solid wastes. A landfill unit has the same liner type (or no liner)
throughout and is bounded either by land on which no waste is placed or by another unit
with a different liner type. A single landfill unit may have adjacent sections, but each must
have the same liner type. (A cluster of naturally occurring pits that had been filled with
solid waste and had the same liner type may also have been classified as a single landfill
unit.)
Table 6.2 summarizes the estimated numbers of landfill units by type;
closed, active and planned. In November, 1986, there were an estimated 6,585 active
-------
landfill units in the United States and territories. This averages to 1.09 active units per
facility. Table 6.2 also includes numbers for closed and planned units. The estimates for
closed and planned units are less reliable than that for active units because many current
facility operators do not have a good idea of past or future activities at a site and thus did
not complete survey questions on these types of units. At landfill facilities with active
landfill units, there were a total of 3,152 closed and 3,847 planned landfill units:
Table 6.2 Reported numbers of landfill units
Landfill unit type
Active landfill units
P j»iii ,, . • jl Ml#%««A*l lAM^Idl •••»•«
Keponec cioseu lanonii units
Reported planned landfill units
TOTAL
Total number
in population
6,585
3,152
3,847
13,564
Average number
per landfill facility
1.09
.52
.64
2.25
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7.1
7. QUANTITIES OF WASTE
Annual Quantity of Waste Received
An estimated 208.8 million tons of waste is received annually by active
Municipal Landfill facilities in the United States and Territories (as of November, 1986).
Table 7.1 shows this result and presents the estimated standard error of the estimate along
with the corresponding 95 percent confidence interval.
Table 7.1 Total annual quantity of waste received
TOTAL
Total amount
(millions of tons)
208.8
Standard
error
12.6
95%
Confidence
interval
184.1 - 233.6
The distribution of the annual quantity of waste across facilities is also of
interest. The majority of facilities receive small quantities of waste and relatively few
facilities receive very large quantities of waste. The average annual quantity of waste
received by a facility is estimated to be 34.6 thousand tons per year. But 83.7 percent of all
facilities are estimated to receive less than this average amount. The "typical" site is
perhaps better represented by the median amount of waste received annually which was
2,830 tons per year.
Table 7.2 gives the distribution of the average annual quantity of waste
received by a facility. The first column gives ranges of amounts of waste received annually
by a facility. The second and third columns list the numbers and percentages of facilities
estimated to fall in the range. The fourth column gives the estimated percentage of waste
accounted for by all facilities in that range. Based on the sample, we estimate that the
largest 21 of the 6,034 facilities in the population received 23.2 percent of all municipal
waste, and the largest 491 facilities received 73.6 percent of all municipal waste.
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Table 7.2 Distribution erf the average annual quantity of waste received
Amount of waste per facility (tons)
1-
10-
100-
1,000-
10,000-
100,000-
1,000,000-
10
100
1,000
10,000
100,000
1,000,000
10,000,000
TOTAL
Number
of facilities
in population
65
597
1,514
1,994
1,373
470
21
6,034
Percentage
of facilities
1.1%
9.9
25.1
33.0
22.8
7.8
.3
100.0%
Percentage
of waste
.0%
.0
.3
4.3
21.8
50.4
23.2
100.0%
7.2
Categories Of Waste Received
Table 7.3 gives the total annual quantity of waste broken down by waste
category. Active municipal landfills are estimated to receive 113.86 million tons of
household waste annually. (Note that the figures in Table 7.3 do not estimate all waste
generated in each category since not all waste is disposed of in landfills, and not all landfills
that receive such waste are classified as municipal landfills.)
By definition, household and commercial waste comprised at least
50 percent of the total waste received by each Municipal Landfill facility. From Table 7.3,
household and commercial waste accounts for about 82 percent of the total waste received.
If, on the other hand, we average the percentages reported by facilities, we find that
household and commercial waste comprises about 89 percent of incoming waste for the
typical facility. This second percentage, 89 percent, is different because it is not weighted
by the total amount received Apparently, small facilities tend to receive higher proportions
of household and commercial waste than do large facilities.
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Table 7.3 Total annual quantity of waste received by category
\
Category of waste
Household wastes
Commercial wastes
Construction/demolition wastes
Industrial process wastes
Sewage sludges
Other wastes
Asbestos-containing materials
Non-municipal incinerator ash
Municipal incinerator ash
Small quant, gen. hazard, wastes
Infectious wastes
TOTAL
Total amount
(million tons)
113.86
58.17
18.18
8.87
4.42
2.39
1.26
.94
.51
.15
.07
208.82
Standard
error
.84
.44
1.47
.78
1.74
.35
.39
.34
.15
.04
.02
12.63
95%
Confidence
interval
112.22 - 115.50
57.30 - 59.04
15.30 - 21.06
7.35 - 10.39
1.02 - 7.83
1.71 - 3.07
.50 - 2.03
.28 - 1.60
.22 - .81
.07 - .24
.04 - .11
184.06 - 233.56
7.3
Capacity of Landfill Facilities
The estimates of used, remaining and total design capacities as measured in
cubic yards are shown in Table 7.4. Of the reported 15,980 million cubic yards total
capacity, 9,503 million cubic yards or 59 percent is still remaining. However, this
percentage is hard to interpret because it is likely that there is additional capacity in closed
units that were not reported. Furthermore, the capacity of potential future units may have
been underrepoited because not all such units were reported as "planned". Many facilities
will plan a new unit, thus increasing capacity, only when it becomes apparent that more
capacity is needed.
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Table 7.4 Total capacity of all municipal landfills facilities
Capacity status
Already used (reported)
Remaining (currently
planned)
TOTAL
Total capacity
(million
cubic yards)
6,477
9,503
15,980
Standard
error
607
654
1,080
95%
Confidence
interval
5,287- 7,667
8,220- 10,786
13,864- 18,096
The distribution of capacity across facilities is also of interest Table 7.5
gives average and median capacities for individual landfills. As with quantity of waste
received, the distribution of capacity is highly skewed. This is evidenced by the fact that
the average value is much larger than the median value.
Table 7.5 Average capacity of a municipal landfill facility
Capacity status
Average capacity
(million cubic yards)
Median capacity
(million cubic yards)
Already used (reported)
Remaining (currently planned)
TOTAL
1.08
1.57
2.65
.14
.16
.39
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The above statistics on capacity were taken from responses to Questions
2.10 and 2.11 which asked for the total design capacity and total remaining design capacity
of the landfill facility in units of cubic yards. Another measure of capacity is in terms of
estimated remaining years of operation which takes into account factors such as remaining
capacity, projected amounts of waste to be received in future years, and early closings
because of legal or economic considerations. Question 1.11 asked for the year in which the
facility was expected to be completely filled. The average remaining life and median
remaining life are estimated to be 21.3 and 12.4 years, respectively.
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8.1
8. FACILITY CHARACTERISTICS
Ownership, Permitting and Age
An estimated 86.1 percent of the Municipal Landfill Facilities are owned by
government entities leaving only 13.9 percent privately owned. Figure 8.1 shows the
distribution of landfill ownership.
Figure 8.1
Distribution of Landfill Ownership
State Govt
Federal Govt
20
Percentage of Facilities
24.9
30
An estimated 91.2 percent of Municpal Landfill facilities have permits.
Most of the permitting was done by state governments. Engineering plans were reviewed
for about 78 percent of the permitted facilities. The average age of a facility is estimated to
be 18.6 years.
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8.2
Proximity to Residences and Drinking Water Sources
The mean distance from the property line to the nearest residence is 2,686
feet The median distance is 1,310 feet
Questions were asked concerning the proximity of water sources to the
landfill facility. Table 8.1 summarizes some of the key results: 41.7 percent of all facilities
are estimated to be located within one mile of private wells; 6.3 percent within one mile of
public wells; .36 percent within one mile of a river or stream; and .6 percent within one
mile of a lake or reservoir. Table 8.2 gives estimates of the numbers of persons to drinking
from such water sources.
Table 8.1 Percentages of landfill facilities within one mile of drinking water sources
Water source type
Percentage of facilities
within one mile
Private wells
Public wells
River/streams
Lake/reservoirs
41.7%
6.3%
3.6%
1.3%
Table 8.2 Total number of persons in the population drinking from water sources within
one mile of a landfill facility
Water source type
Private wells
Public wells
River/streams
Lake/reservoirs
Total number
of persons
(thousands)
67
666
852
424
Standard
error
13
357
341
203
95%
Confidence
interval
42- 92
104- 1,365
423- 1,521
177 - 822
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Some respondents may have had problems determining the number of
wells, lakes or reservoirs within one mile of their facility, whether they are used for
drinking water, and estimating how many persons use these water sources for drinking
water. Moreover, the problem is especially difficult for rivers and streams since the intake
point may be hundreds of miles away. When clarifications were sought by respondents,
they were instructed to include a river or stream as a drinking water source only if the
intake point was within five miles of the landfill facility. Because of the difficulties in
answering these questions and possible variablity in the assumptions made by respondents
when answering this question about rivers and streams, these results should be interpreted
with caution.
8.3 Hydrogeology
Hydrogeological questions were concerned with the flow of water through
the facility and the geology of the area. Table 8.3 lists percentages of facilities with certain
hydogeological location characteristics.
Among specific types of soils, the most common type mentioned was clay
followed by sandy clay, sand, clayee soil and silt. Table 8.4 gives the estimated
percentages of facilities that have various soil types. Each facility was asked to list the
single most predominant (primary) soil type and all other (secondary) soil types that
occurred between bedrock and the bottom of the landfilled waste. Figure 8.2 presents
these results graphically.
Table 8.3 Percentages of facilities with certain location characteristics
Location characteristic
Percentage
of facilities
Located in a 100-year floodplain
Located in an area designated as a wetland
Located in karst terrain
Not located completely above the seasonal
high water table
12.8%
5.6
3.8
7.3
-------
Table 8.4 Soil types between bedrock and the bottom of landfilled wastes
Soil type
Clay
Sandy clay
Sand
Clayee soil
Silt
Other
TOTAL
Percentage of time listed as:
Primary
35.1%
20.7
13.8
9.1
3.6
17.8
100.0%
Secondary
24.9%
26.9
24.2
20.6
21.8
21.7
Total
60.0%
47.6
38.0
29.7
25.4
39.5
(Multiple responses allowed)
Figure 8.2
Soil Types Between Bedrock and the Bottom of Landfilled Wastes
I
3
Primary
Secondary
20
40
60
80
Percentage of Facilities
-------
8.4
Monitoring
Table 8.5 summarizes the percentages of facilities that monitored ground
water, surface water, air and gas. The most common type of monitoring is the monitoring
of ground water with an estimated 35.8 percent of facilities conducting this type of
monitoring. Next came the monitoring of surface water (15.3% of facilities), gas (6.7% of
facilities) and air (2.7% of facilities).
Table 8.5 Percentages of facilities that monitor water, gas and air
Type of monitoring
Percentage
of facilities
Ground Water
Surface Water
Gas
Air
35.8%
15.3
6.7
2.7
A number of questions were directed at the frequency of ground-water
monitoring. Table 8.6 summarizes the results. Among facilities that reported conducting
ground-water monitoring, there were a average of 2.1 ungradient and 3.8 downgradient
wells. Well were sampled about three times per year with about two samples taken for
each sampling period. On the average, sampling had been conducted for about five years.
Table 8.6 Number of wells and amount of sampling at facilities that monitor ground
water
Characteristic
Number of wells
Sampling periods per year well
Samples per well per sampling period
Years wells have been sampled
Upgradient
wells
2.1
3.3
1.9
5.0
Downgradient
wells
3.8
3.2
2.1
5.1
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9. UNIT CHARACTERISTICS
9.1
Size and Capacity
Table 9.1 summarizes the average surface area and average capacity of
closed, active, and planned landfill units. An active landfill unit is estimated to cover an
average of 32.5 acres and to have an average capacity of one and a half million cubic yards
of waste.
Table 9.1 Average surface area and capacity for closed, active and planned landfill units
Characteristic
Surface area (acres)
Capacity (million cubic yards)
Type of landfill unit
Closed
9.1
.4
Active
32.5
1.5
Planned
18.8
1.0
9.2
Liners
Table 9.2 gives estimated percentages of landfill units that were reported to
have specific liner types and Table 9.3 gives the estimated thickness for each type. For
example, for active sites, we estimate that 27.5 percent of all active landfill units have In-
Situ Clay liners with an average thickness of 29.6 feet
-------
Table 9.2 Liner types for closed, active and planned landfill units
Liner type
In-situ clay
Re-compacted clay
Soil
Synthetic membrane
Asphalt
Other
None or unknown
Percentage of landfill units
with liner type
Gosed
33.8%
16.8
17.9
.4*
.1*
7.6
39.0
Active
27.5%
18.6
20.7
1.1
.1**
6.6
39.7
Planned
30.2%
20.2
15.4
6.4
.1
8.0
34.5
* Estimated standard error of estimate exceeds 25 percent of estimate
** Estimated standard error of estimate exceeds 50 percent of estimate
Table 9.3 Liner thickness by liner type for closed, active and planned landfill units
Liner type
In-situ clay (feet)
Recomputed clay (feet)
Soil (feet)
Synthetic membrane (mils)
Asphalt (inches)
Other (feet)
Type of landfill unit
Closed
17.1
2.8
20.8*
20.0*
.1**
22.3
Active
29.6
4.0
17.5*
44.8
7.6**
25.6*
Planned
11.9
3.5
24.6*
52.8
1.0**
28.5*
* Estimated standard error of estimate exceeds 25 percent of estimate
** Estimated standard error of estimate exceeds 50 percent of estimate
-------
Figure 9.1 below shows the percentages of active landfill units with specific
liner types. The column chart is stacked in order to show separately the percentages where
a liner type is reported alone or in combination with other liner type or types. Multiple
responses were permitted for liner types.
Figure 9.1
Liner Types for Active Landfill Units:
Alone and in Combination with Other Liner Types
I
Asphalt
Synth Membrane
Other
Re-compact Clay
Soil
In Situ Clay
None or Unknown
• Alone
H With Others
10
20
30
40
Percentage of Active Units
9.3
Final Covers
Table 9.4 gives estimated percentages of landfill units that were reported to
have specific final cover types and Table 9.5 gives the estimated thickness for each type.
For example, for active sites, we estimate that 49.8 percent of all active landfill units have
soil final covers with an average thickness of 2.0 feet
-------
Table 9.4 Final cover types for closed, active and planned landfill units
Final cover type
Soil
Sand or gravel
Re-compacted clay
Synthetic membrane
Topsoil
Other
Unknown
Percentage of landfill units
with final cover type
Gosed
50.8%
11.7
32.3
1.4*
33.6
9.8
2.8
Active
49.8%
14.2
32.4
1.7
37.3
5.2
6.0
Planned
49.5%
10.4
32.9
2.5
37.3
10.2
4.3
* Estimated standard error of estimate exceeds 25 percent of estimate
Table 9.5 Final cover thickness by final cover type for closed, active and planned landfill
units
Final cover type
Soil (feet)
Sand or gravel (feet)
Re-compacted clay (feet)
Synthetic membrane (mils)
Topsoil (feet)
Other (feet)
Type of landfill unit
Gosed
2.0
2.0
2.2
34.5
1.3
2.8
Active
2.0
2.0
2.1
36.2
1.2
2.0
Planned
2.1
2.5
1.8
32.4
1.1
2.6
Figure 9.2 below, analogous to Figure 9.1 for liners, shows the
percentages of active landfill units with specific final cover types. The column chart is
-------
stacked in order to show separately the percentages where a final cover type is reported
alone or in combination with other liner type or types. Multiple responses were permitted
for liner types.
Figure 9.2
Final Cover Types for Active Landfill Units:
Alone and in Combination with Other Final Cover Types
Synth Membrane
Alone
With Others
I
10
30
Percentage of Active Unite
40
50
9.4
Leachate Collection
Leachate collection systems were reported for an estimated 7.8 percent of
closed, 11.5 percent of active, and 21.2 percent of planned landfill units. These increasing
percentages suggest that such systems are becoming more common over time. Table 9.6
shows estimated percentages of landfill units that use, or will use, specific leachate disposal
methods. Multiple responses were permitted for a unit
-------
Table 9.6 Leachate disposal methods for closed, active and planned landfill units
Type of landfill unit
Leachate disposal method
Recirculate
Spray on active landfill area
Injection
Other
Land application, spread, or treatment
Truck to POTW or Sewer
Discharge through sewer to POTW
Discharge to surface water
Other or unknown off-site treatment
On-site treatment
Biological
Physical/chemical
Gosed
17.2%*
4.3**
4.4**
4.7**
14.5*
18.4*
16.0*
.4**
17.5*
13.2**
Active
21.0%
5.1*
5.1*
12.6*
21.6
16.8
13.5*
2.7**
14.2*
7.0*
Planned
30.4%
1.9**
3.2*
9.1*
39.5
16.2
3.4**
3.2**
16.6
7.3*
* Estimated standard error of estimate exceeds 25 percent of estimate
** Estimated standard error of estimate exceeds 50 percent of estimate
-------
APPENDIX A
SUMMARY STATISTICS FOR SELECTED QUESTIONS
Statistics are presented in this appendix in a question and answer format
similar to the Solid Waste Landfill Survey Questionnaire (see Appendix A). Some
questions have been reworded slightly. Estimates are reported for approximately half of
the questions asked in the questionnaire.
Two types of statistics are reported: averages and percents. In most cases
averages are for all landfill facilities or units; exceptions are noted or can be gleaned from
wording of the question. Percents reported for subparts to a question may not add up to
100 because (1) there was rounding, (2) multiple responses were allowed or (3) the set of
respondents varied by subpart.
Stratified estimates were computed for all results presented. All estimates
are subject to error. An indication is given of the sampling variability of the estimates. For
averages, asterisks following the estimates have the following interpretation:
* One asterisk indicates that the estimated standard error of the average
is greater than 25 percent of the estimate; and
** Two asterisks indicate that the estimated standard error of the
average is greater than 50 percent of the estimate.
A similar convention is used for percentages:
* One asterisk indicates that the estimated standard error of the
percentage is greater than either 25 percent of the estimate or
25 percent of 100 minus the estimate, whichever is less; and
** Two asterisks indicate that the estimated standard error of the
percentage is greater than either 50 percent of the estimate or
50 percent of 100 minus the estimate, whichever is less.
With one asterisk, a 95 percent confidence interval for an estimate (an average or
percentage less than 50 percent) will be at least as wide as an interval ranging from half the
estimate to one and a half times the estimate. With two asterisks, the confidence interval
will be at least as wide an interval ranging from zero to twice the estimate.
-------
Part 1: Landfill Facility, Owner, and Operator
Ql.S Which one of the following categories best describes the landfill facility
owner'f (Only one response allowed.)
Percent
3.3 Federal
.9 State
28.8 County
28.3 City
24.9 Other government
13.9 Private
Q1.7 Does this landfill facility have a solid waste permit or license!
Percent
91.2 Yes
Ql.S Who issued the solid waste permit or license? (Multiple responses
allowed.)
Percent (computed for facilities that report having a permit or license)
90.9 State Government
10.4 County Government
1.8 City Government
6.1 Other government
Q1.9 Did the authority that issued the permit or license review any engineering
plans before issuing the permit or license?
Percent (computed for facilities that report having a permit or license)
78.4 Yes
Ql. 10 In what year was waste first placed in any of the landfill units at this landfill
facility?
Average
1967 Year
-------
Ql.ll In what year do you expect all active (and planned) landfill units at this
facility to be completely filled?
Average
2007 Year
Part 2: Facility Jurisdiction, Size, and Operations
Q2.7 What is the shortest distance from the edge of the property line to a
residence?
Average
2,686 Feet
Q2.8 What is the shortest distance from the edge of the landfill unit to a
residence?
Average
3,194 Feet
Q2.9 What is the total area of this landfill facility? Include all buildings, buffer
areas, lagoons and holding ponds, and roads on the property as well as
landfill areas.
Average
86.5 Acres
Q2.10 What is the total design capacity of this landfill facility? Include the
combined total amount of waste that the active, closed, and planned landfill
units will hold. Do not include the volume of cover material in your
estimate.
Average
2,648,292 Cubic Yards
-------
Q2.11 What is the total remaining design capacity of this landfill facility? Include
the additional waste volume that all active, unused, and planned landfill
units can hold. Total remaining design capacity is the total design capacity
(provided in Question 2.10), minus the amount of waste currently in the
landfills.
Average
1,574,877 Cubic Yards
Q2.12 Which landfill method(s) does this facility use? (Multiple responses
allowed.)
Percent
48.4 Area Fill Method
66.9 Trench or Cell Method
5.5 Other Method
Q2.13 Which waste processing technique(s) does this facility use prior to
landfilling? (Multiple responses allowed.)
Percent
2.1 Baling
1.7 Shredding
38.8 Other Technique
Q2.16 What is the ratio of waste to cover material at this landfill facility?
Average
4.4 to 1 Ratio.
Part 3: Hydrogeologic and Water Source Information
Q3.1 Is any pan of this landfill facility located in any of the following? (Multiple
responses allowed.)
Percent
12.8 a 100-year floodplain.
5.6 an area designated as a wetland
3.8 karst terrain
-------
Q3.2 Identify the single most predominant type of soil between bedrock and the
bottom of the landfilled wastes. (Only one response allowed.)
Percent
13.8 Sand
9.1 ClayeeSand
3.6 Silt
20.7 Sandy Clay
35.1 day
17.8 Other
100.0
Q3.3 Identify all other soil types occurring between bedrock and the bottom of the
landfilled wastes. (Multiple responses allowed.)
Percent
24.2 Sand
20.6 Clayee Sand
21.8 Silt
26.9 Sandy Clay
24.9 day
21.7 Other
Q3.4 Is this landfill facility located completely above the seasonal high water
table?
Percent
92.8 Yes
Q3.5 What is the average distance from the bottom of the landfilled wastes to the
seasonal high water table?
Average (computed for facilities located above the seasonal high water
table)
85.7 Feet
Q3.9 What sources of information did you use to answer hydrogeologic question
3.1 - 3.8 above? (Multiple responses allowed.)
Percent
29.0 Site-Specific Hydrogeologic Study
18.4 General Literature Sources (e.g., County Report)
14.3 State Agency
69.3 No Hydrogeologic Data Available; "Best Estimates" Provided
-------
Q3.10 How many downgradient private and public drinking water wells are within
one mite of the edge of any landfill unit?
Average
6.99 Private Wells
.14 Public Wells
Also estimate the number of people using drinking water wells within one
mile of the edge of any landfill unit
Average
11.1 People Use Private Wells for Drinking Water
110.3** People Use Public Wells for Drinking Water
Q3.ll How far away from the edge of any landfill unit are the closest
downgradient drinking water wells? Give the distance separately for the
closest private and public well (if within 1 mile).
Average (computed for facilities that report having such a well)
1,835 Feet to Closest Private Well
2,327 Feet to Closest Public Well
Q3.13 How many downgradient rivers/streams and lakes/reservoirs that are used
for drinking water are within one mile of the edge of any landfill unit?
Average
.040 Rivers/Streams
.017* Lakes/Reservoirs
Also, estimate the number of people who use these sources for drinking
water.
Average (computed for facilities that report having these sources)
i
141.2* People Who Use Rivers/Streams for Drinking Water
70.3* People Who Use Lakes/Reservoirs for Drinking Water
-------
Q3.14 How far away from the edge of any landfill unit are the closest
downgradient river/stream and lake/reservoir that are used for drinking
water! Give the distance separately for the closest river/stream and
lake/reservoir (if within 1 mile).
Average (computed for facilities that report having such a source)
1,936 Feet to Gosest River/Stream
3,397 Feet to Closest Lake/Reservoir
Q3.18 What sources of information did you use to answer water source questions
3.10-3.17 above? (Multiple responses allowed.)
Percent
19.0 Site-Specific Water Source Study
11.1 Local Water Department
72.8 No Water Source Data Available; "Best Estimates" Provided
16.0 Other
Part 4: Waste Characteristics
Q4.1 What is the average annual quantity of waste received at this landfill facility?
Average
34,604 Tons Per Year
Q4.2 Estimate the average annual percent of the waste received at this landfill
facility in each of the waste categories listed.
Percent
71.8 Household Wastes
17.3 Commercial Wastes
. 1 Small Quantity Generator Hazardous Wastes
.2 Asbestos-Containing Materials
5.9 Construction/Demolition Wastes
2.7 Industrial Process Wastes
. 1 * Infectious Wastes
.1* Municipal Incinerator Ash
. 2 Other Incinerator Ash
.5 Sewage Sludges
1.2 Other Wastes
-------
Also, for which categories does this facility refuse to accept waste?
Percent
A** Household Wastes
5.5 Commercial Wastes
71.5 Small Quantity Generator Hazardous Wastes
55.9 Asbestos-Containing Materials
15.4 Construction/Demolition Wastes
43.5 Industrial Process Wastes
67.9 Infectious Wastes
53.8 Municipal Incinerator Ash
51.5 Other Incinerator Ash
54.1 Sewage Sludges
2.7 Other Wastes
Q4.3 Of the total amount of industrial process wastes received at this landfill
facility, estimate the percent received from each of the industrial categories
listed below.
Percent (computed for facilities that report receiving industrial process
waste)
.4** Electric Power Generation
3.2* Fertilizer/Agricultural Chemicals
21.5 Food and Related Products and Byproducts
1.7* Inorganic Chemicals
5.9* Iron and Steel Manufacturing
2.6** Leather and Leather Products
4.2* Non-Ferrous Metals Manufacturing/Foundries
.3* Organic Chemicals
.2* Petroleum Refining Industry
8.9* Plastics and Resins Manufacturing
9.3 Pulp and Paper Industry
7.5 Rubber and Misc. Plastic Products
9.4 Stone, Glass, Clay, and Concrete Products
14.4 Textile Manufacturing
.7* Transportation Equipment
.8* Water Treatment
9.1 Other
-------
Also, for which categories does this facility refuse to accept waste?
Percent (computed for facilities that report receiving industrial process
waste)
27.8 Electric Power Generation
32.8 Fertilizer/Agricultural Chemicals
7.1* Food and Related Products and Byproducts
32.0 Inorganic Chemicals
16.7 Iron and Steel Manufacturing
15.9 Leather and Leather Products
16.3 Non-Ferrous Metals Manufacturing/Foundries
32.9 Organic Chemicals
30.0 Petroleum Refining Industry
16.9 Plastics and Resins Manufacturing
18.4 Pulp and Paper Industry
14.1 Rubber and Misc. Plastic Products
10.4* Stone, Glass, Clay, and Concrete Products
15.9 Textile Manufacturing
22.5 Transportation Equipment
24.2 Water Treatment
.9** Other
Q4.4 What percent of the total facility wastes received by this landfill facility are
bulk liquids and drummed/containerized wastes?
Percent
. 14 Bulk Liquids (not containerized)
.05* Drummed/Containerized Liquids
.09* Drummed/Containerized Other Waste Forms
Also, for which categories does this facility refuse to accept waste?
Percent
65.7 Bulk Liquids (not containerized)
65.8 Drummed/Containerized Liquids
62.5 Drummed/Containerized Other Waste Forms
Q4.7 Does this landfill facility have separate disposal or management areas for
specific wastes?
Percent (computed for facilities that report having a liner of the given type)
46.0 Yes
-------
Q4.8 Does this landfill facility have a separate disposal or management area for
asbestos!
Percent
6.9 Yes
Part 5 Individual Landfill Unit Information
QS. 1 How many closed, active, and planned landfill units are there at this facility?
Average
.52 Number Closed
1.09 Number Active
.64 Number Planned
Closed Landfill Units
QC3. What is the total area of the landfill unit?
Average
9.1 Acres
QC4. What is the total volume of the landfill unit?
Average
358,070 Cubic Yards
QC9. What types of liners are used? (Multiple responses allowed.)
Percent
33.8 In-Situ Gay
16.8 Re-compacted Clay
17.9 Soil
.4* Synthetic Membrane
.1* Asphalt
7.6 Other
39.0 None or Unknown
-------
QC10. What is the layer thickness for each type of liner used?
Average
17.1 Feet, In-Situ Clay
2.8 Feet, Re-compacted Clay
20.0* Feet, Soil
20.0* Mils, Synthetic Membrane
1.0** Inches, Asphalt
22.3 Feet, Other
QC13. What types of final cover an used! (Multiple responses allowed.)
Percent
50.8 Soil Layer
11.7 Sand or Gravel Layer
32.3 Re-compacted day Layer
1.4* Synthetic Membrane
33.6 Topsoil Layer
9.8 Other
2.8 Unknown
QC14. What is the layer thickness for each type of cover used?
Average
2.0 Feet, Soil Layer
2.0 Feet, Sand or Gravel Layer
2.2 Feet, Re-compacted Gay Layer
34.5 Mils, Synthetic Membrane
1.3 Feet, Topsoil Layer
2.8 Feet, Other
QC 17. Does this landfill unit have a leachate collection system1*
Percent
7.8 Yes
-------
QC20. What is done with any leachate collected in this landfill unit? (Multiple
responses allowed.)
Percent
17.2* Recirculate - Spray on active landfill area
4.3** Recirculate • Injection
4.4** Recirculate - Other
4.7** Land Application, Spreading or Treatment
14.5* Truck to POTW or Sewer
18.4* Discharge through Sewer to POTW
16.0* Discharge to Surface Water
.4** Other or Unknown Off-site Treatment
17.5* On-site Treatment -Biological
13.2** On-site Treatment - Physical/Chemical
Active Landfill Units
QA3. What is the total area of the landfill unit?
Average
32.5 Acres
QA4. What is the total volume of the landfill unit?
Average
1,528,274 Cubic Yards
QA10. What types cf liners are used? (Multiple responses allowed.)
Percent
27.5 In-Situ Clay
18.6 Re-compacted Clay
20.7 Soil
1.1 Synthetic Membrane
.1** Asphalt
6.6 Other
39.7 None or Unknown
-------
QA11. What is the layer thickness for each type of liner used?
Average
29.6 Feet, In-Situ Clay
4.0 Feet, Re-compacted Clay
17.5* Feet, Soil
44.8 Mils, Synthetic Membrane
7.6** Inches, Asphalt
25.6* Feet, Other
QA14. What types of final cover are planned? (Multiple responses allowed)
Percent
49.9 Soil Layer
14.2 Sand or Gravel Layer
32.5 Re-compacted day Layer
1.7 Synthetic Membrane
37.3 TopsoU Layer
5.2 Other
6.0 Unknown
QA 15. What will be the layer thickness for each type of cover planned?
Average
2.0 Feet, Soil Layer
2.0 Feet, Sand or Gravel Layer
2.1 Feet, Re-compacted Clay Layer
36.2 Mils, Synthetic Membrane
1.2 Feet, TopsoU Layer
2.0 Feet, Other
QA 18. Does this landfill unit have a leachate collection system!
Percent
11.5 Yes
-------
QA21. What is done with any leachate collected in this landfill unit? (Multiple
responses allowed.)
Percent
21.0 Recirculate - Spray on active landfill area
5.1* Reciiculate - Injection
5.1* Reciiculate - Other
12.6* Land Application, Spreading or Treatment
21.6 Truck to POTW or Sewer
16.8* Discharge through Sewer to POTW
13.5* Discharge to Surface Water
2.7** Other or Unknown Off-site Treatment
14.2* On-site Treatment - Biological
7.0* On-site Treatment - Physical/Chemical
Planned Landfill Units
QP3. What is the total area of the landfill unit?
Average
18.8 Acres
QP4. What is the planned total volume of the landfill unit?
Average
1,026,630 Cubic Yards
QP6. What types of liners are planned? (Multiple responses allowed.)
Percent
30.2 In-Situ Clay
20.2 Re-compacted Gay
15.4 Soil
6.4 Synthetic Membrane
.1 Asphalt
8.0 Other
34.5 None or Unknown
-------
QP7. What will be the layer thickness for each type of liner planned?
Average
11.9 Feet, In-Situ Clay
3.5 Feet, Re-compacted Gay
24.6* Feet, Soil
52.8 Mils, Synthetic Membrane
1.0** Inches, Asphalt
28.5* Inches, Other
QP10. What types of final cover are planned? (Multiple responses allowed.)
Percent
49.5 Soil Layer
10.4 Sand or Gravel Layer
32.9 Re-compacted Clay Layer
2.5 Synthetic Membrane
37.3 Topsoil Layer
10.2 Other
4.3 Unknown
QP11. What will be the layer thickness for each type of cover planned?
Average
2.1 Feet, Soil Layer
2.5 Feet, Sand or Gravel Layer
1.8 Feet, Re-compacted Clay Layer
32.4 Mils, Synthetic Membrane
1.1 Feet, Topsoil Layer
2.6 Feet, Other
QP14. Will this landfill unit have a leachate collection system!
Percent
21.2 Yes
-------
QP17. What will be done with any leachate collected in this landfill unit? (Multiple
responses allowed.)
Percent
30.4 Recirculate - Spray on active landfill area
1.9** Recirculate - Injection
3.2** Recirculate-Other
9.1* Land Application, Spreading or Treatment
39.5 Truck to POTW or Sewer
16.2 Discharge through Sewer to POTW
3.4** Discharge to Surface Water
3.2** Other or Unknown Off-site Treatment
16.6 On-site Treatment - Biological
7.3* On-site Treatment - Physical/Chemical
Part 6: Monitoring Systems
Q6.1 Does all or part of this landfill facility have any of the following, either
completed or under construction? (Multiple responses allowed.)
Percent
6.7 A Landfill Gas Monitoring or Detection System
2.1 A Landfill Gas Recovery System
Q6.3 Is the ground water monitored at this landfill facility?
Percent
35.8 Yes
Q6.4 How is the ground water is monitored at this landfill facility? (Multiple
responses allowed.)
Percent (computed for facilities that monitor ground water)
39.1 Individual Landfill Units Have Monitoring Wells
83.0 Overall Facility Has a Monitoring System
-------
Q6.6 Describe the upgradient ground-water monitoring wells at this landfill
facility.
• Average (computed for facilities that monitor ground water)
2.1 Number of wells
63.2 Feet, depth of wells from ground surface
3.3 Number of times wells are sampled per year
1.9 Number of samples per well per sampling period
5.0 Years, longest time any of these wells have been sampled?
Describe the downgradient ground-water monitoring wells at this landfill
facility.
Average (computed for facilities that monitor ground water)
3.8 Number of wells
54.2 Feet, depth of wells from ground surface
3.3 Number of times wells are sampled per year
2.1 Number of samples per well per sampling period
5.1 Years, longest time any of these wells have been sampled?
Q6.7 Has this landfill facility ever been found to be a source of ground-water
contamination by any government authority?
Percent
2.1 Yes
Q6.9 Does this landfill facility monitor air emissions!
Percent
2.7 Yes
Q6.10 Does mis landfill facility monitor surface water!
Percent
15.3 Yes
Q6.11 How many times per year is surface water sampled at this facility?
Average (for facilities that monitor surface water)
3.5 Times per year
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Part 7: Landfill Operating Costs and Revenues
Q7.2 What is die approximate total annual operating cost of this landfill facility?
Average
$270,030 Per year
$51.70 Per ton
Q7.5 What is the average tipping fee per ton of waste disposed at this landfill
facility for each of the categories below?
Average (computed for facilities that reported a tipping fee by the ton, cubic
yard, or no fee at all)
$ 1.77 Per Ton, for Commercial and Residential Wastes
.39 Per Ton, for Sewage Sludges
.22 Per Ton, for Municipal and Other Incinerator Ash
1.56 Per Ton, for Non-hazardous Industrial Process Waste
Average (computed only for facilities that reported a tipping fee by the
carload)
$7.48 Per Carload or Truckload, for Commercial and Residential
Wastes
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