Sanitary Landfill
Design and Operation
This report (SW-287) was written by
Dirk R. Brunner and Daniel J. Keller
U.S. ENVIRONMENTAL PROTECTION AGENCY
1972
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5th printing, October 1980
An environmental protection publication
in the solid waste management series (SW-287)
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, B.C. 20402
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Sanitary Landfill Design and Operation is a state-of-the-art treatise. It
not only describes the known in sanitary landfill technology, it also indicates
areas in which research is needed.
This publication represents the combined efforts of many individuals
within the Federal solid waste management program, other Federal agencies,
State and local governments, private industry, and universities.
It is the hope of the U.S. Environmental Protection Agency that planners,
designers, operators, and government officials will use this document as a
tool to help overcome the poor land disposal practices that are evident today.
—SAMUEL HALE, JR.
Deputy Assistant Administrator
for Solid Waste Management
Hi
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ChaPter page
1. THE SOLID WASTE PROBLEM 1
2. SOLID WASTE DECOMPOSITION 3
Leachate
Contaminant Removal
Decomposition Gas
3. HYDROLOGY AND CLIMATOLOGY 10
Surface Water
Groundwater
Climatology
4. SOILS AND GEOLOGY 13
Soil Cover
Land Forms
5. SANITARY LANDFILL DESIGN 20
Volume Requirements
Site Improvements
Clearing and grubbing
Roads
Scales
Buildings
Utilities
Fencing
Control of Surface Water
Groundwater Protection
Gas Movement Control
Permeable methods
Impermeable methods
Sanitary Landfilling Methods
Cell construction and cover material
Trench method
Area method
Combination methods
Summary of Design Considerations
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Chapter page
6. SANITARY LANDFILL OPERATION 31
Hours of Operation
Weighing the Solid Waste
Traffic Flow and Unloading
Handling of Wastes
Residential, commercial, and industrial plant
wastes
Bulky wastes
Institutional wastes
Dead animals
Industrial process wastes
Volatile and flammable wastes
Water and wastewater treatment plant sludges
Incinerator fly ash and residue
Pesticide containers
Animal manure
Radioactive wastes and explosives
Placement of Cover Material
Daily cover
Intermediate cover
Final cover
Maintenance
Weather Conditions
Fires
Salvage and Scavenging
7. EQUIPMENT 39
Equipment Functions
Waste handling
Cover material handling
Support functions
Equipment Types and Characteristics
Crawler machines
Rubber-tired machines
Landfill compactors
Scrapers
Dragline
Special-purpose equipment
Accessories
Comparison of characteristics
Size of Operation
Single-machine sites
Small sites
Multiple-machine operation
Costs
Capital Costs
Operating and maintenance costs
8. COMPLETED SANITARY LANDFILL 48
Characteristics
Decomposition
Density
Settlement
Bearing capacity
Landfill gases
Corrosion
Uses
Green area
Agriculture
Construction
Recreation
Registration
vi
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Chapter
9.
MANAGEMENT
Administrative Agency
Municipal operations
Special districts
County operations
Private operations
Administrative Functions
Finances
Operational cost control
Performance evaluation
Personnel
Public relations
BIBLIOGRAPHY
page
52
ACKNOWLEDGMENTS
56
59
List of tables
page
Table 1 Composition of initial leachate from municipal solid waste 4
Table 2 Groundwater quality near a landfill 6
Table 3 Landfill gas composition 8
Table 4 Suitability of soil types as cover material 14
Table 5 Soil classification and characteristics pertinent to sanitary landfills 17
Table 6 Application of cover material 35
Table 7 Insecticides for fly control 37
Table 8 Accessories for landfill equipment 44
Table 9 Performance characteristics of landfill equipment 45
Table 10 Landfill equipment needs 45
Table 11 Machine capital cost 46
List of figures
page
Figure 1 Concentration of cations in leachate 5
Figure 2 Concentration of anions in leachate 6
Figure 3 Gas production from an experimental sanitary landfill 7
Figure 4 Leachate and infiltration movements affected by soil and bedrock .13
Figure 5 Textural classification chart 16
Figure 6 Yearly volume of waste from a community of 10,000 20
Figure 7 Daily volume of waste from large communities 21
Figure 8 Daily volume of waste from small communities 21
Figure 9 Special litter-control fences near a landfill's working face 23
Figure 10 Diversion ditch to transmit upland drainage around a landfill 23
VII
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List of figures (continued) page
Figure 11 Gravel vents or gravel-filled trenches to control lateral gas movement 25
Figure 12 Gases vented via pipes inserted through top cover 26
Figure 13 Clay as a liner or curtain wall to block underground gas flow 26
Figure 14 Cell construction and cover material 27
Figure 15 Trench method of sanitary landfilling 28
Figure 16 Area method of sanitary landfilling 28
Figure 17 Slope or ramp method of sanitary landfilling 29
Figure 18 Reduction of cushioning and bridging on working face of slope 33
Figure 19 Crawler dozer used for grading 40
Figure 20 Crawler loader with a general-purpose bucket 41
Figure 21 Crawler loader with a multiple-purpose bucket 41
Figure 22 Rubber-tired dozer 41
Figure 23 Rubber-tired loader 41
Figure 24 Steel-wheeled landfill compactor 42
Figure 25 Landfill compactor wheels 43
Figure 26 Scrapers 43
vtn
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the solid waste problem
The Nation is emerging from a prolonged
period in which it neglected solid waste manage-
ment, and it is becoming increasingly aware that
our present solid waste storage, collection, and
disposal practices are inadequate. Much of this
awareness has been brought about by active cam-
paigns directed against air and water pollution and
has resulted in a third campaign—the abatement of
land pollution.
The magnitude of the problem can be appre-
ciated when we consider that the Nation produced
250 million tons of residential, commercial, and
institutional solid wastes in 1969. Only 190 million
tons were collected. Much of the remainder found
its way to scattered heaps across the countryside,
was left to accumulate in backyards and vacant lots,
or was strewn along our roadways. To compound
the problem, an estimated 110 million tons of indus-
trial wastes and nearly 4 billion tons of mineral and
agricultural wastes were generated.
Because of our affluence and increasing popu-
lation, these quantities are expected to increase. In
1920, solid waste collected in our urban areas
amounted to only 2.75 Ib per capita. In 1970, the
figure stood at over 5 Ib, and it is estimated that
it will reach 8 Ib by 1980.
Solid waste processing and disposal practices
are grossly inadequate for today's needs. Only 6
percent of land disposal operations and 25 percent
of incinerator facilities were considered adequate in
the 1968 National Solid Wastes Survey.1
This inadequacy is the result of lack of plan-
ning and financing and, until recently, public apathy
with regard to our environment. There has been far
too little effort made to locate and reserve suitable
areas for land disposal operations in anticipation
of community growth. Consequently, it is becoming
more and more difficult to locate disposal sites in
urban areas. This directly affects disposal costs,
because hauling expenses to a suitable landfill site
increase or a more expensive alternative method of
processing is required prior to disposal.
More than 90 percent of our Nation's solid
waste is directly disposed of on land, the vast
majority of it in an unsatisfactory manner. Open
and burning dumps, which are all too common,
contribute to water and air pollution and p'rovide
food, harborage, and breeding grounds for insects,
birds, rodents, and other carriers of disease. In
addition, these dumps are unsightly and very often
lessen the value of nearby land and residences. In
response to an aroused public, legislation has been
passed on the local, State, and Federal levels to aid
the development of satisfactory disposal practices
and to plan for all aspects of solid waste manage-
ment. The development and implementation of such
plans will, however, require the combined support
of all citizens, industry, and government.
An acceptable alternative to the present poor
practices of land disposal is the sanitary landfill.
This alternative involves the planning and applying
of sound engineering principles and construction
techniques. Sanitary landfilling is an engineered
method of disposing of solid wastes on land by
spreading them in thin layers, compacting them
to the smallest practical volume, and covering them
with soil each working day in a manner that protects
the environment. By definition, no burning of solid
waste occurs at a sanitary landfill. A sanitary land-
fill is not only an acceptable and economic method
of solid waste disposal, it is also an excellent way
to make otherwise unsuitable or marginal land
valuable.
Thorough planning and the application of sound
engineering principles to all stages of site selection,
design, operation, and completed use will result in
329-340 0 -
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a successful and efficient sanitary landfill. In order
to meet this objective, it is also essential to have
an understanding of solid waste decomposition pro-
cesses—how the many variables may affect the
decomposition rate, decomposition products, and
how these factors may influence the environment.
In essence, these relationships determine the physi-
cal stability of the fill and its potential to produce
such environmental problems as uncontrolled gas
generation and movement and water pollution.
Although these relationships are not fully under-
stood, sufficient knowledge is available to enable
us to recognize potential problems and to plan and
design sanitary landfills that will not harm the
environment.
The final selection of a sanitary landfill site, its
design, and its operation should be based on a
systematic, integrated study and an evaluation of
all physical conditions, economics, and social politi-
cal restraints.
REFERENCE
1. BLACK, R. J., A. J. MUHICH, A. J. KLEE, H. L. HICKMAN, JR., and R. D.
VAUGHAN. The national solid wastes survey; an interim report.
[Cincinnati], U.S. Department of Health, Education, and Welfare,
[1968]. 53 p.
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solid waste decomposition
A knowledge of solid waste decomposition pro-
cesses and the many influences they exert is essen-
tial to proper sanitary landfill site selection and
design.
Solid wastes deposited in a landfill degrade
chemically and biologically to produce solid, liquid,
and gaseous products. Ferrous and other metals are
oxidized; organic and inorganic wastes are utilized
by microorganisms through aerobic and anaerobic
synthesis. Liquid waste products of microbial deg-
radation, such as organic acids, increase chemical
activity within the fill. Food wastes degrade quite
readily, while other materials, such as plastics,
rubber, glass and some demolition wastes, are
highly resistant to decomposition. Some factors
that affect degradation are the heterogeneous char-
acter of the wastes, their physical, chemical, and
biological properties, the availability of oxygen and
moisture within the fill, temperature, microbial pop-
ulations, and type of synthesis. Since the solid
wastes usually form a very heterogeneous mass of
nonuniform size and variable composition and other
factors are complex, variable, and difficult to con-
trol, it is not possible to accurately predict con-
taminant quantities and production rates.
Biological activity within a landfill generally
follows a set pattern. Solid waste initially decom-
poses aerobically, but as the oxygen supply is ex-
hausted, facultative and anaerobic microorganisms
predominate and produce methane gas, which is
odorless and colorless. Temperatures rise to the
high mesophilic-low thermophilic range (60 to 150F)
because of microbial activity. Characteristic pro-
ducts of aerobic decomposition of waste are carbon
dioxide, water, and nitrate. Typical products of
anaerobic decomposition of waste are methane, car-
bon dioxide, water, organic acids, nitrogen, am-
monia, and sulfides of iron, manganese, and hy-
drogen.
Leachate
Groundwater or infiltrating surface water mov-
ing through solid waste can produce leachate, a
solution containing dissolved and finely suspended
solid matter and microbial waste products. Leachate
may leave the fill at the ground surface as a spring
or percolate through the soil and rock that underlie
and surround the waste.
Composition of leachate is important in deter-
mining its potential effects on the quality of nearby
surface water and groundwater. Contaminants car-
ried in leachate are dependent on solid waste com-
position and on the simultaneously occurring physi-
cal, chemical, and biological activities within the
fill. Identification of leachate composition has been
the object of several laboratory lysimeter and field
studies.'•*
The chemical and biological characteristics of
leachate were determined in two studies conducted
over a period of time with solid waste of the same
general type at both sites (Table 1). The data exhibit
a significant range of values. As an example, pH of
the leachate investigated in study A was found to
vary between 6.0 and 6.5' while pH in study B
varied between 3.7 and 8.5.2 Chloride varied from
96 to 2,350 mg per liter in study A and from 47
to 2,340 in study B. Although the leachates for the
two studies were similar in many respects, there
were differences which further indicate the varia-
bility of leachate composition with time for indi-
vidual sites and between sites. For example, mean
sulfate concentrations were 614 mg per liter for
study A, ranging from 730 near the start of the
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TABLE 1
Composition of Initial Leachate*
from Municipal Solid Waste
Component
Study A1
Study B2
Low High Low High
pH 6.0 6.5 3.7 8.5
Hardness, CaC03 890 7,600 200 550
Alkalinity, CaC03 730 9,500
Ca 240 2,330
Mg 64 410
Na 85 1,700 127 3,800
K 28 1,700
Fe (total) 6.5 220 0.12 1,640
Ferrous iron 8.7t 8.7t
Chloride 96 2,350 47 2,340
Sulfate 84 730 20 375
Phosphate 0.3 29 2.0 130
Organic-N 2.4 465 8.0 482
NH«-N 0.22 480 2.1 177
BOD 21,700 30,300
COD 809 50,715
Zn 0.03 129
Ni 0.15 0.81
Suspended solids 13 26,500
'" Average composition, mg per liter of first 1.3 liters of
leachate per cubic foot of a compacted, representative,
municipal solid waste.
t One determination.
test to 84 near the conclusion. Sulfate concentra-
tions in study B averaged 152 mg per liter, ranging
from 375 at the beginning of sampling to 20 at
the conclusion.
The quantity of contaminants in leachate from
a completed fill where no more waste is being dis-
posed of can be expected to decrease with time.
Only a few studies have attempted to determine the
effect of long term leaching of solid waste.1'3 Much
more research is needed in the laboratory and in
the field to adequately describe this phenomenon.
The limited data available indicate a removal of
large quantities of contaminants by leaching during
active stages of decomposition, and a slackening off
of removal as the fill stabilizes (Figures 1, 2). If
the fill is considered as a mass of material contain-
ing a finite amount of leachable material, then
depending on the removal rate, leaching should
eventually cease.
The types and quantities of contaminants that
enter the receiving water and the ability of that
water to assimilate these contaminants will deter-
mine 'the degree of leachate control needed. In some
cases it may be established that introduction of
leachate will not upset the ecology or usefulness of
the receiving water. Careful examination of dilution
and oxygen demand criteria of the stream can be
useful tools in showing the ability of a stream to
assimilate leachate. In all cases, water quality cri-
teria and the laws and ordinances of Federal, State,
and local agencies pertaining to water pollution
must be followed.
Some investigators believe that even in a sani-
tary landfill, leachate production is inevitable and
that some leachate will eventually enter surface
water or groundwater. This has not been proven but
neither has the opposite view. The present philos-
ophy held by the Office of Solid Waste Management
Programs, most State solid waste control agencies,
and many experts in the field is that through sound
engineering and design, leachate production and
movement may be prevented or minimized to the
extent that it will not create a water pollution prob-
lem. The most obvious means of controlling leachate
production and movement is to prevent water from
entering the fill to the greatest extent practicable.
Contaminant Removal
Leachate percolating through soils underlying
and surrounding the solid waste is subject to puri-
fication (attenuation) of the contaminants by ion
exchange, filtration, adsorption, complexing, pre-
cipitation, and biodegradation. It moves either as an
unsaturated flow if the voids in soil are only partially
filled with water or as a saturated flow if they are
completely filled. The type of flow affects the mech-
anism of attentuation, as do soil particle size and
shape and soil composition.
Attentuation of contaminants flowing in the
unsaturated zone is generally greater than in the
saturated zone because there is more potential for
aerobic degradation, adsorption, complexing, and
ion exchange of organics, inorganics, and microbes.
Aerobic degradation of organic matter is more rapid
and complete than anaerobic degradation. Because
the supply of oxygen is extremely limited in sat-
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2500-1
2000-
1500-
Z
1000-
UJ
(J
z
o
u
z
i soo H
Calcium
Magnesium Q
200 400 600 800 1000 1200
WATER APPLIED AFTER SATURATION (gallons)
1400
13
217 306 350
ELAPSED TIME AFTER SATURATION (days)
419
Figure. 1 Concentration of cations in leachate; adapted from Reference 1.
488
urated flow, anaerobic degradation prevails. Adsorp-
tion and ion exchange are highly dependent on the
surface area of the liquid and solid interface. The
surface area to flow volume ratio is greater in an
unsaturated flow than in a saturated flow.
Leachate travel in the saturated zone is pri-
marily controlled by soil permeability and hydraulic
gradient, but a limited amount of capillary diffusion
and dispersion do occur. The leachate is diluted very
little in groundwater unless a natural geologic mix-
ing basin exists. Leachate movement will closely
follow the streamlines of groundwater flow.
Information on leachate travel in the unsat-
urated zone is lacking. Most of the studies made
of residential and industrial wastewaters traveling
through the unsaturated zone indicate that the
organic and microbial removal level achieved is
very good. As an example, when a citrus liquid
waste was applied to the ground surface, COD was
reduced from 5,000 mg per liter to less than 100
in the top 3 ft of soil.7 However, the rate and fre-
quency at which the waste liquid is applied and the
type of soil have great influence on attenuation effi-
ciency. Nitrification can also occur in the unsat-
urated soil zone and produce nitrate and nitrite
from ammonia-nitrogen. A water that was bacteriolo-
gically safe, according to USPHS Drinking Water
Standards for the coliform group, was obtained by
percolating settled domestic waste water through
at least 4 ft of a fine, sandy loam soil.8 This last
study is especially important since pathogens have
been detected in solid waste and leachate.''10
Travel of leachate in the saturated zone has
been monitored by several investigators,4'5'" but
more research is needed to clearly define its signifi-
cance. Results obtained so far indicate that the
distance the contaminants travel depends on the
composition of the soil, its permeability, and the
type of contaminant. Organic materials that are
biodegradable do not travel far, but inorganic ions
and refractive organics can travel appreciable dis-
tances. Some inorganic contaminants from a dump
located in an abandoned gravel pit have been traced
for 1,200 ft.4 Contaminant movement was through
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Ł
\
O)
O
Of
I—
UJ
u
Z
O
u
g
z
2500
2000
1500
1000
500
Chloride
Sulfote
5 Oo-O O—O
200 400 600 800 1000
WATER APPLIED AFTER SATURATION (gallons)
1200
1400
13 95 217 306 350
ELAPSED TIME AFTER SATURATION (days)
Figure 2. Concentration of anions in leachate; adapted from Reference 1.
419
488
a highly porous glacial alluvium. Another study indi-
cates that the rate of movement through some soils
is so slow that the full impact of contaminant travel
may not be realized for many years.5 If contaminant
travel is slow, the release of contaminants to an
aquifer would also be slow.
Inorganic materials appear to be most resistant
to attenuation. This is especially true of chloride ion,
and it serves, therefore, as a good indicator of leach-
ate movement. Data from monitoring wells surround-
ing a landfill in Illinois reflected a sharp increase in
chlorides and total dissolved solids (Table 2). Chlo-
ride concentrations in the unaffected groundwater
were 18 mg per liter, those in the fill were 1,710,
and those in a monitoring well 150 ft downstream
of the fill were 248.
Natural purification processes have only a lim-
ited ability to remove contaminants, because the
number of adsorption sites and exchangeable ions
available is finite. In addition, the processes are
time dependent—residence time is shortened by high
flow rates. Flow rates through soils near landfills
TABLE 2
Groundwater Quality in the
Vicinity of a Landfill5
Characteristic
Background Fill* Monitor well*
mg/1 mg/1 mg/1
Total dissolved solids
PH
COD
Total hardness
Sodium
Chloride
636 6,712 1,506
7.2 6.7 7.3
20 1,863 71
570 4,960 820
30 806 316
18 1,710 248
* Groundwater quality in a saturated fill and in a monitor-
ing well located approximately 150 ft downstream from
the landfill at a depth of 11 ft in sandy, clayey silt.
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may be reduced naturally by filtering and settling
of suspended contaminants. Porosity and permea-
bility of the soil are then reduced. Thus, additional
protection against contaminant travel may be pos-
sible as time passes. (Analysis of precipitation,
flooding, upland drainage, and evapo-transpiration
necessary to determine whether leaching will occur
at a site is discussed later.)
Decomposition Gas
Gas is produced naturally when solid wastes
decompose. The quantity generated in a landfill and
its composition depend on the types of solid waste
that are decomposing. A waste with a large fraction
of easily degradable organic material will produce
more gas than one that consists largely of ash and
construction debris. The rate of gas production is
governed solely by the level at which microbial
decomposition is occurring in the solid waste. When
decomposition ceases, gas production also ends.
In a field study conducted over a 907-day period,
approximately 40 cu ft of gas were produced per
cu yd of solid waste.12 Gas production was monitored
throughout the duration of this study (Figure 3).
Theoretically, if decomposition is carried to comple-
tion, each Ib of solid waste containing 25 percent
inerts can produce up to 6.6 cu ft of gas.
Methane and carbon dioxide are the major
constituents of landfill decomposition gas, but other
gases are also present and some may impart a
repugnant odor. Hydrogen sulfide, for example, may
be generated at a landfill, especially if it contains
a large amount of sulfate, such as gypsum board
(calcium sulfate) or if brackish water infiltrates the
solid waste.
Limited studies have been made on the vary-
ing composition of landfill gas over a period of time
(Table 3). The data indicate that the percentages
of carbon dioxide and methane present three months
after solid wastes were placed in the fill were 88 and
5, respectively; four years later the respective fig-
ures were 51 and 48. Very little methane is pro-
duced during the early stages of decomposition
because aerobic synthesis prevails.
Landfill gas is important to consider when
evaluating the effect a landfill may have on the en-
vironment, because methane can explode and be-
cause mineralization of groundwater can occur if
carbon dioxide dissolves and forms carbonic acid.
Methane is explosive only when present in air at
concentrations between 5 and 15 percent. Since
there is no oxygen present in a landfill when meth-
ane concentrations in it reach this critical level,
there is no danger of the fill exploding. If, however,
methane vents into the atmosphere (its specific
2000
S"
3
1500
O
LU 1000
3
6
>
<
i
u
500
100 200 300 400 500 600 700
ELAPSED TIME SINCE CELL CONSTRUCTION (days)
800
900
Figure 3. Gas production from an experimental sanitary landfill; adapted from Reference 12. Gas production
is from 40 cu yd of residential solid waste at a density of 634 Ib per cu yd with a moisture content (wet weight)
of 34.6 percent. Composition of the solid waste used, on a percentage basis: paper (42.7); grass and garden
clippings (38); plastic (3); glass (5); metal (7); dirt (5).
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TABLE 3
Landfill Gas Composition1
Time interval since start
of cell completion
(months)
0-3
3-6
6-12
12-18
18-24
24-30
30-36
36-42
42-48
Average
N2
5.2
3.8
0.4
1.1
0.4
0.2
1.3
0.9
0.4
percent
C02
88
76
65
52
53
52
46
50
51
by volume
CH4
5
21
29
40
47
48
51
47
48
gravity is less than that of air) it may accumulate
in buildings or other enclosed spaces on or close
to a sanitary landfill.
The potential movement of gas is, therefore, an
essential element to consider when selecting a site.
It is particularly important if enclosed structures are
built on or adjacent to the sanitary landfill or if it
is to be located near existing industrial, commercial,
and residential areas.
Gas permeability of the soils surrounding the
landfill can influence the movement of decomposi-
tion gas. A dry soil will not significantly impair its
flow, but a saturated soil, such as clay, can be an
excellent barrier. A well-drained soil acts as a
vent to gas flow. If cover material acts as a barrier,
then the landfill gases will migrate laterally until
they can vent to the atmosphere. More research is
needed to reliably predict rate and distance of gas
movement.
Landfill gas movement can be controlled if
sound engineering principles are applied. Of the
several methods that have been devised and tested,
permeable vents and impermeable barriers are the
two basic types. Both are discussed in Chapter 5.
REFERENCES
1. California State Water Pollution Control Board. Report on the investigation
of leaching of a sanitary landfill. Publication No. 10. Sacramento,
1954. [92 p.]
2. FUNGAROLI, A. A. Pollution of subsurface water by sanitary landfill. (In
preparation.)
3. QASIM, S. R. Chemical characteristics of seepage water from simulated
landfills. Ph.D. Dissertation, West Virginia University, Morgantown,
1965. 145 p.
4. ANDERSEN, J. R., and J. N. DORNBUSH. Influence of sanitary landfill on
ground water quality. Journal American Water Works Association, 59
(4):457-470, Apr. 1967.*
5. HUGHES, G. M., R. A. LANDON, and R. N. FARVOLDEN. Hydrogeology of
solid waste disposal sites in northeastern Illinois; a final report on
a solid waste demonstration grant project. Washington, U.S. Gov-
ernment Printing Office, 1971. 154 p.
6. Ministry of Housing and Local Government. Pollution of water by tipped
refuse; report of the Technical Committee on the experimental dis-
posal of house refuse in wet and dry pits. London, Her Majesty's Sta-
tionery Office, 1961. 141 p.
7. ANDERSON, D. R., W. D. BISHOP, and H. F. LUDWIG. Percolation of citrus
wastes through soil. In Proceedings; 21st Industrial Waste Confer-
ence, May 3-5, 1966. Lafayette, Ind., Purdue University, p. 892-901.
8. California State Water Pollution Control Board. Field investigation of waste
water reclamation in relation to ground water pollution. Publication
No. 6. Sacramento, 1953. 124 p.
9. WEAVER, L. Refuse disposal, its significance. In Ground Water Contamina-
tion; Proceedings of the 1961 Symposium, Cincinnati, Apr. 5-7, 1961.
Technical Report W61-5. Robert A. Taft Sanitary Engineering Center.
p. 104-110.
' This land disposal site does not meet the standard for a sanitary landfill.
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10. COOK, H. A., D. L CROMWELL, and H. A. WILSON. Microorganisms in
household refuse and seepage water from sanitary landfills. In Pro-
ceedings; West Virginia Academy of Science, 39:107-114. 1967.
11. County of Los Angeles, Department of County Engineer and Engineering-
Science, Inc. Development of construction and use criteria for
sanitary landfills; an interim report. Cincinnati, U.S. Department of
Health, Education, and Welfare, 1969. [267 p.]
12. MERZ, R. C., and R. STONE. Special studies of a sanitary landfill. Washing-
ton, U.S. Department of Health, Education, and Welfare, 1970. (Dis-
tributed by National Technical Information Service, Springfield, Va.,
as PB-196 148. 240 p.)
329-3l»0 0-80-3
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*»,.,
hydrology and climatology
A major consideration in selecting the site for
a sanitary landfill and in designing it is the hydrol-
ogy of the area. To a large extent, hydrology will
determine whether the formation of leachate will
produce a water pollution problem.
When solid wastes are placed in a sanitary
landfill, they may vary tremendously with regard to
moisture content. Wood, concrete, and other con-
struction rubble may have very little, whereas many
food wastes may be extremely wet. Paper, a major
constituent of solid waste, is usually quite low in
moisture. Metals and glass are also generally pres-
ent in solid waste but are essentially free of mois-
ture.
In general, the moisture content of mixed solid
waste generated by a community ranges from 20 to
30 percent by weight. (Wide fluctuations can occur
depending on climatic conditions during storage and
collection.) In this general range, the moisture alone
should not produce leachate provided the solid waste
is fairly well mixed and has been well compacted.
The water that results from decomposition of the
relatively small amounts of intermixed food wastes
and other moist, readily degradable organics can
be absorbed by the comparatively large amounts of
paper and other dry components present.
Leachate is not produced until all of the sani-
tary landfill or a sizable portion of it becomes
saturated by water entering it from outside. For this
reason, it is extremely important that a study of the
site hydrology be made. Precipitation, surface runoff
characteristics, evapo-transpiration, and the location
and movement of groundwater with relation to the
solid waste are the major factors that should be
considered.
Surface Water
Surface water that infiltrates the cover soil and
enters the underlying solid waste can increase the
rate of waste decomposition and eventually cause
leachale to leave the solid waste and create water
pollution problems. Unless rapid decomposition is
planned and the sanitary landfill is so designed that
leachate is collected and treated, as much surface
water as is practicable should be kept from entering
the fill.
The permeability of a soil is the measure of the
ease or difficulty with which water can pass through
it. This is greatly affected by the texture, gradation,
and structure of the soil and the degree to which it
has been compacted. Coarse grained soils (gravels
and sands) are usually much more permeable than
fine grained soils (silts and clays). However, small
amounts of silts and clays (fines) in a coarse
grained soil may greatly decrease permeability
while cracks in fine grained soils may do the
opposite.*
The quantity of water that can infiltrate the
soil cover of a sanitary landfill depends not only on
these physical characteristics but also on the resi-
dence time of the surface water. It can be minimized
by: (1) diverting upland drainage; (2) grading and
sloping the daily and final cover to allow for runoff;
(3) decreasing the permeability of the cover ma-
terial.
There have been few detailed investigations
' Specific information on the percentage of water infil-
trating a particular soil can be obtained from the Soil
Conservation Service, U.S. Department of Agriculture
10
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made of the quantity of moisture that can enter a
sanitary landfill through a cover and on the amount
and quality of water that may leave the fill and
enter an aquifer or stream. One investigator claims,
however, that it is possible to predict the quantity
of surface water that will enter the underlying solid
waste if the available water storage capacity, quan-
tity, and frequency of water infiltration, and rates
of evaporation and transpiration for a cover material
are known.1 Under ideally controlled laboratory con-
ditions or at a field test site, this would seem plausi-
ble, but more studies must be made of leaching
potentials at operational sanitary landfills. These are
needed because the placement of cover soils cannot
be rigidly controlled and some discontinuities al-
ways develop in the structure of a sanitary landfill.
They derive from variations in soil thickness, tex-
ture, and degree of compaction as well as from
slight changes that occur in the grade or slope of
the cover soil when it settles; this may cause cracks
or fissures to develop. Furthermore, slight varia-
tions in the amount or intensity of rainfall, minor
changes in vegetation, or other presumably less im-
portant alterations of the fill's final surface may
have major effects on the amount of surface mois-
ture entering the solid waste.
Groundwater
Groundwater is water that is contained within
the zone of saturation of soil or rock—that is, all
the pores in the containing earth materials are
saturated. This zone is just beneath the land sur-
face in many parts of the country and is on the
surface at many springs, lakes, and marshes. In
some areas, notably most of the arid west, the zone
of saturation is deep in the ground.
The water table is the surface where water
stands in wells at atmospheric pressure. In highly
permeable formations, such as gravel, the water
table is essentially the top of the zone of saturation.
In many fine grained formations, however, capillary
action causes water to rise above this zone, and the
inexperienced observer might think this capillary
fringe is part of the zone.
The zone of saturation commonly is not con-
tinuous with depth nor does it necessarily have later-
al continuity. In exploring for underground water, a
saturated zone may be found that yields water at
a shallow depth, but if the exploration hole is con-
tinued, dry material is encountered at a greater
depth and then another zone of saturation is found.
Isolated high zones or lenses of saturated material
are referred to as perched water. Perched water is
common to glacial soil (till plain) areas where inter-
stratified lenses or patches of porous sand and
gravel are underlaid by relatively impervious glacial
clay.
Because the conditions affecting groundwater
occurrence are so complex, it is essential that the
sanitary landfill site investigation include an evalu-
ation by a qualified groundwater hydrologist. This
is needed not only to locate the zone of saturation
but also to predict the direction and rate of flow of
groundwater and the quality of the aquifer.
Leachate from a landfill can contaminate
groundwater. In order to determine if leachate will
produce a subsurface pollution problem, it is es-
sential that the quality of the groundwater be es-
tablished and that the aquifer's flow rate and direc-
tion be determined. Water within the zone of satura-
tion is not static. It moves vertically and laterally
at varying rates, depending on the permeability of
the soil or rock formation in which it is located and
the external hydraulic forces acting upon it.
The movement of groundwater is determined
by using a tracer such as fluorescein dye or by
making piezometer readings. The estimated quan-
tity of groundwater flow is based on the permeabil-
ity of the aquifer, effective cross-sectional flow area,
and the pressure gradient that induces the water
to move. The groundwater hydrologist should also
determine whether the aquifer is in a discharge or
recharge area. In a discharge area, water leaves
the aquifer and emerges through the ground sur-
face as a spring. In recharge areas, water infiltrates
the ground and enters the aquifer. Lakes, streams,
and rivers may serve as recharge or discharge areas,
or both, depending on the surrounding groundwater
level and geologic conditions.
Climatology
Wind, rain, and temperature directly affect
sanitary landfill design and operation. Windy sites
need to have litter fences at the operating area and
personnel to clean up the area at the end of the
day. Such sites can also be very dusty when the
soil dries, and this may irritate people living or
working nearby. Trees planted on the perimeter of
a sanitary landfill help keep dust and litter within
the site. Water sprinkling or the use of other dust
palliatives are often necessary along haul roads
constructed of soil, crushed stone, or gravel.
The effect of rain that infiltrates the sanitary
landfill and influences solid waste decomposition
has been discussed previously. Rain can also cause
operational problems; many wet soils are difficult to
spread and compact, and traffic over such soils is
impeded.
11
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Freezing temperatures may also cause prob- may be required, or it may be necessary to stockpile
lems. If the frost line is more than 6 in. below the cover soil and protect it from freezing. A well-drained
ground surface, cover material may be difficult soil is more easily worked in freezing weather than
to obtain. A crawler dozer equipped with a ripper one that is poorly drained.
REFERENCE
1. REMSON, I., A. A. FUNGAROLI, and A. W. LAWRENCE. Water movement
in an unsaturated sanitary landfill. Journal of the Sanitary Engineer-
ing Division, Proc. ASCE, 94(SA2):307-317, Apr. 1968.
12
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soils and geology
A study of the soils and geologic conditions
of any area in which a sanitary landfill may be
located is essential to understanding how its con-
struction might affect the environment. The study
should outline the limitations that soils and geo-
logic conditions impose on safe, efficient design
and operation.
A comprehensive study identifies and describes
the soils present, their variation, and their dis-
tribution. It describes the physical and chemical
properties of bedrock, particularly as it may relate
to the movement of water and gas (Figure 4). Per-
meability and workability are essential elements of
the soil evaluation, as are stratigraphy and structure
of the bedrock.
Rock materials are generally classified as sedi-
mentary, igneous, or metamorphic. Sedimentary
rocks are formed from the products of erosion of
older rocks and from the deposits of organic mat-
ter and chemical precipitates. Igneous rocks derive
from the molten mass in the depths of the earth.
Metamorphic rocks are derived from both igneous
and sedimentary rocks that have been altered chem-
ically or physically by intense heat or pressure.
Sands, gravels, and clays are sedimentary in
origin. The sedimentary rocks, sometimes called
Surface runoff
X
LIMESTONE SOLUTION WIDENED JOINTS!
- *\ __JL 1
I 1
<—r—u—i t—r
.'i";J/-* •.''."•;': Permeable sandstone
Figure 4. Leachate and infiltration movements are affected by the characteristics of the soil and bedrock.
13
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aqueous rocks, are often very permeable and there-
fore represent a great potential for the flow of
groundwater. If leachate develops and enters the
rock strata, contaminant travel will usually be great-
est in sedimentary formations. Other rocks common-
ly classed as sedimentary are limestone, sandstone,
and conglomerates. Fracturing and jointing of sedi-
mentary formations are common, and they increase
permeability. In fact, the most productive water-
bearing strata for wells are formations of porous
sandstone, highly fractured limestone, and sand
and gravel deposits. Siltstones and shales, which
are also of sedimentary origin, usually have a very
low permeability unless they have been subjected to
jointing and form a series of connected open frac-
tures.
Igneous and metamorphic rocks, such as shist,
gneiss, quartzite, obsidian, marble, and granite,
generally have a very low permeability. If these rocks
are fractured and jointed, however, they can serve
as aquifers of limited productivity. Leachate move-
ment through them should not, therefore, be cate-
gorically discounted.
Information concerning the geology of a pro-
posed site may be obtained from the U.S. Geologi-
cal Survey, the U.S. Army Corps of Engineers, State
geological and soil agencies, university departments
of soil sciences and geology, and consulting soil
engineers and geologists.
Soil Cover
The striking visual difference between a dump
and a sanitary landfill is the use of soil cover at the
latter. Its compacted solid waste is fully enclosed
within a compacted earth layer at the end of each op-
erating day, or more often if necessary.
The cover material is intended to perform
many functions at a sanitary landfill (Table 4); ideal-
ly, the soil available at the site should be capable
of performing all of them.
The cover material controls the ingress and
egress of flies, discourages the entrance of rodents
seeking food, and prevents scavenging birds from
feeding on the waste. Tests have demonstrated that
6 in. of compacted sandy loam will prevent fly emer-
gence.1 Daily or more frequent application of soil
cover greatly reduces the attraction of birds to the
waste and also discourages rodents from burrowing
to get food. The cover material is essential for
maintaining a proper appearance of the sanitary
landfill.
Many soils, when suitably compacted, have a
low permeability, will not shrink, and can be used to
control moisture that might otherwise enter the
solid waste and produce leachate.
Control of gas movement is also an essential
function of the cover material. Depending on antic-
ipated use of the completed landfill and the sur-
TABLE 4
Suitability of General Soil Types as Cover Material"
Function
Minimize moisture entering
Minimize landfill gas venting
through cover
Provide pleasing appearance
and control blowing paper
Grow vegetation
Be permeable for venting
decomposition gast
Clean Clayey-silty Clean Clayey-silty
gravel gravel sand sand
Silt
P
P
E
P
F-G
F-G
E
G
P
P
E
P-F
G-E
G-E
E
E
G-E
G-E
E
G-E
Clay
Prevent rodents from burrowing
or tunneling
Keep flies from emerging
G
P
F-G
F
G
P
P
G
P
G
P
Et
Et
Et
E
F-G
* E, excellent; G, good; F, fair; P, poor
t Except when cracks extend through the entire cover.
t Only if well drained.
14
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rounding land, landfill gases can be either blocked
by or vented through the cover material. A perme-
able soil that does not retain much water can serve
as a good gas vent. Clean sand, well-graded gravel,
or crushed stone are excellent when kept dry. If
gases are to be prevented from venting through the
cover material, a gas-impermeable soil with high
moisture-holding capacity compacted at optimum
conditions should be used.
Enclosing the solid waste within a compacted
earth shell offers some protection against the spread
of fire. Almost all soils are noncombustible, thus
the earth side walls and floor help to confine a fire
within the cell. Top cover over a burning cell offers
less protection because it becomes undermined and
caves in, thus exposing the overhead cell to the fire.
The use of a compactible soil of low permeability is
an excellent fire-control measure, because it
minimizes the flow of oxygen into the fill.
To maintain a clean and sightly operation,
blowing litter must be controlled. Almost any work-
able soil satisfies this requirement, but fine sands
and silts without sufficient binder and moisture con-
tent may create a dust problem.
The soil cover often serves as a road bed for
collection vehicles moving to and from the operating
area of the fill. When it is, it should be trafficable
under all weather conditions. In wet weather, most
clay soils are soft and slippery.
In general, soil used to cover the final lift
should be capable of growing vegetation. It should,
therefore, contain adequate nutrients and have a
large moisture-storage capacity. A minimum com-
pacted thickness of 2 ft is recommended.
Comparison of the soil characteristics needed
to fulfill all of these functions indicates that some
anomalies exist. To serve as a road base, the soil
should be well-drained so that loaded collection
vehicles do not bog down. On the other hand, it
should have a low permeability if water is to be
kept out of the fill, fire is to be kept from spreading,
and gas is not to be vented through the final cover.
These differences can be solved by placing a suit-
able road base on top of the normally low
permeability-type cover material. A reverse situation
occurs when landfill gases are to be vented uni-
formly through the cover material. The soil should
then be gas permeable, have a small moisture-
storage capacity, and not be highly compacted. As
before, the criteria for moisture and fire control re-
quire the soil to have a low permeability. Leachate
collection and treatment facilities may be required
if a highly permeable soil is used to vent gas uni-
formly through the cover materials; if this is not
done, an alternative means of venting gas through
the cover material must be sought.
There are many soils capable of fulfilling the
functions of cover material. Minor differences in
soil grain size or clay mineralogy can make signifi-
cant differences in the behavior of soils that fall
within a given soil group or division. In addition,
different methods of placing and compacting the
same soil can result in a significantly different be-
havior. Moisture content during placement, for ex-
ample, is a critical factor—it influences the soil's
density, strength, and porosity.
The soils present at proposed sites should be
sampled by augering, coring, or excavating, and
then be classified. The volume of suitable soil avail-
able for use as cover material can then be estimated
and the depth of excavation for waste disposal can
be determined. Specific information on the top 5
ft of the soil mantle can often be obtained from the
Soil Conservation Service, U.S. Department of Agri-
culture.
Sanitary landfilling is a carefully engineered
process of solid waste disposal that involves appre-
ciable excavating, hauling, spreading, and compact-
ing of earth. When manipulating soils in this man-
ner, the Unified Soil Classification System (USCS)
is useful. Although recommendations for soil to be
used at a landfill are often expressed in the U.S.
Department of Agriculture textural classification
system (Figure 5), the USCS is preferred because it
relates in more detail the workability of soils from
an engineering viewpoint. (Table 5).
Clay soils are very fine in texture even though
they commonly contain small to moderate amounts
of silt and sand. They vary greatly in their physical
properties, which depend not only on the small
particle size but on the type of clay minerals and
soil water content. When dry, a clay soil can be
almost as hard and tough as rock and can sup-
port heavy loads. When wet, it often becomes very
soft, is sticky or slippery, and is very difficult to
handle. A clay soil swells when it becomes wet, and
its permeability is very low.
Many clay soils can absorb large amounts of
water but, after drying, usually shrink and crack.
These characteristics make many clays less desir-
able than other soils for use as a cover material.
The large cracks that usually develop allow water
to enter the fill and permit decomposition gases to
escape. Rats and insects can also enter or leave
the fill through these apertures.
Clay soil can, however, be used for special
purposes at a landfill. If it is desirable to construct
an impermeable lining or cover to control leachate
and gas movement, many clays can be densely com-
pacted at optimum moisture. Once they are in place,
it is almost always necessary to keep them moist
so they do not crack.
15
-------
The suitability of coarse grained material
(gravel and sand) for cover material depends most-
ly on grain size distribution (gradation), the shape
of grains, and the amount of clay and silt fines
present. If gravel, for example, is poorly graded and
relatively free of fines, it is not suitable as cover
material for moisture, gas, or fly control. It cannot
be compacted enough, and the gravel layer will be
porous and highly permeable; this would allow water
to enter the fill easily. Flies would have little diffi-
culty emerging through the loose particles. On the
other hand, a gravel layer no more than 6 in. deep
would probably discourage rats and other rodents
from burrowing into the fill and would provide good
litter control. If gravel is fairly well-graded and con-
tains 10 to 15 percent sand and 5 percent or more
100
100 90 80 70 60 50 40 30 20 10
90
100
Sieve openings in inches
3 2 l'/2 1 3/4 '/2
Sand — 2 0 to 0 05 mm diameter
Silt —005 to 0002 mm diameter
Clay — smaller than 0.002 mm. diameter
COMPARISON OF PARTICLE SIZE SCALES
U.S. Standard Sieve Numbers
i 4 10 20 40 60 200
I I TI I 1 11 I I I [ I I I Mill 1
USDA
uses
GRAVEL
GRAVEL
Coarse | Fine
SAND
coarsejC°arse| Med
... 1 Very
Flne | fine
SILT
CLAY
SAND
Coarse
Medium 1 Fine
SILT OR CLAY
HUM i I i nun i i
11—1
1 T 0.42 0.
0.5
I
I
_L
I
I
I
100 50
10
0.25 0.1 / 0.05 0.02 0.01 0.005 0.0002 0.001
0.074
Grain size in Millimeters
Figure 5. Textural classification chart (U.S. Department of Agriculture) and comparison of particle size scales.
16
-------
ARY LAND
in ,_
UJ *—'
CD as
-------
fines, it can make an excellent cover. When com-
pacted, the coarse particles maintain grain-to-grain
contact, because they are held in place by the bind-
ing action of the sand and fines and cohesion of
the clays. The presence of fines greatly decreases
a soil's permeability. A well-graded, sandy, clayey
gravel does not develop shrinkage cracks. It can
control flies and rodents, provide odor control, can
be worked in any weather, and supply excellent
traction for collection trucks and other vehicles.
Many soils classified as sand (grain size gen-
erally in the range of 4.0 to 0.05 mm) contain small
amounts of silt and clay and often some gravel-size
material as well. A well-graded sand that contains
less than 3 percent fines usually has good compac-
tion characteristics. A small increase in fines, par-
ticularly silt, usually improves density and allows
even better compaction. A poorly graded sand is
difficult to compact unless it contains abundant
fines. The permeability of clean sand soils is al-
ways high, even when compacted, and they are not,
therefore, suitable for controlling the infiltration of
water. They are also ineffective in constraining flies
and gases.
A well-drained sandy soil can be easily worked
even if temperatures fall below freezing, while a
soil with a large moisture-storage capacity will
freeze.
Practically the only soils that can be ruled
out for use as cover material are peat and highly
organic soils. Peat is an earthy soil (usually brown
to black) and is composed largely of partially de-
composed plant matter. It usually contains a high
amount of voids, and its water content may range
from 100 to 400 percent of the weight of dried
solids. Peat is virtually impossible to compact,
whether wet or dry. Peat deposits are scattered
throughout the country but are most abundant in
the States bordering the Great Lakes. Highly or-
ganic soils include sands, silts, and clays that con-
tain at least 20 percent organic matter. They are
usually very dark, have an earthy odor when freshly
turned, and often contain fragments of decompos-
ing vegetable matter. They are very difficult to com-
pact, are normally very sticky, and can vary ex-
tremely in their moisture content.
Many soils contain stones and boulders of
varying sizes, especially those in glaciated areas.
The use of soils with boulders that hinder compac-
tion should be avoided.
Soil surveys prepared by the Soil Conservation
Service of the U.S. Department of Agriculture are
available for a major portion of the country. Local
assistance in using and interpreting them is avail-
able through soil conservation districts located in
some 3,000 county seats throughout the United
States. The surveys cover such specific factors as
natural drainage, hazard of flooding, permeability,
slope, workability, depth to rock, and stoniness.
They are commonly used to locate potential areas
for sanitary landfills. They also can serve as the
basis for designing effective water management
systems and selecting suitable plant cover to con-
trol runoff and erosion during and after completion
of fill operations. Sanitary landfill owners and their
consultants can avoid costly investigations of un-
suitable sites by using soil surveys to select areas
for which detailed investigations appear warranted.
Using soil surveys for the foregoing purposes does
not, however, eliminate the need for making detailed
site investigations.
Land Forms
A sanitary landfill can be constructed on vir-
tually any terrain, but some land forms require that
extensive site improvements be made and expensive
operational techniques followed. Flat or gently roll-
ing land not subject to flooding is best, but this
type is also highly desirable for farming and indus-
trial parks, and this drives up the purchase price.
Depressions, such as canyons and ravines, are
more efficient than flat areas from a land use stand-
point since they can hold more solid waste per
acre. Cover material may, however, have to be hauled
in from surrounding areas. Depressions usually re-
sult when surface waters run off and erode the
soil and rock. By their nature, they require special
measures to keep surface waters from inundating
the fill. Permeable formations that intersect the
side walls or floor of the fill may also have to be
lined with an impervious layer of clay or other ma-
terial to control the movement of fluids.
There are also numerous man-made topo-
graphic features scattered over the country—strip
mines, worked-out stone and clay quarries, open
pit mines, and sand and gravel pits. In most cases,
these abandoned depressions are useless, dangerous
eyesores. Many of them could be safely and eco-
nomically reclaimed by utilizing them as sanitary
landfills. Clay pits, for example, are located in most
impermeable formations, which are natural barriers
to gas and water movement. Abandoned strip mines
also are naturally suited for use as sanitary land-
fills. Most coal formations are underlaid by clays,
shales, and siltstones that have a very low perme-
ability. When permeable formations, such as sand-
stones, are encountered near an excavation, imper-
meable soil layers can be constructed from the near-
by abundant spoil. Abandoned limestone, sandstone,
siltstone, granite, and traprock quarries and open
18
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pit mines generally require more extensive improve-
ments because they are in permeable or often open-
fractured formations. The pollution potential of sand
and gravel pits is great, and worked-out pits con-
sequently require extensive investigation and proba-
bly expensive improvements to control gas move-
ment and water pollution.
Marsh and tidal lands may also be filled, but
they are less desirable from an ecological point of
view. They have little value as real estate, but
possess considerable ecological value as nesting and
feeding grounds for wildlife. Filling of such areas
requires, however, the permanent lowering of the
groundwater or the raising of the ground surface to
keep organic and soluble solid waste from being
deposited in standing water. Roads for collection
vehicles are also needed, and cover material gen-
erally has to be hauled in.
REFERENCE
1. BLACK, R. J., and A. M. BARNES. Effect of earth cover on fly emergence
from sanitary landfills. Public Works, 89(2):91-94, Feb. 1958. Con-
densed and reprinted as Fly emergence control in sanitary landfills.
Refuse Removal Journal, 1(5):13, 25, May 1958.
19
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sanitary landfill design
The designing of a sanitary landfill calls for
developing a detailed description and plans that
outline the steps to be taken to provide for the
safe, efficient disposal of the quantities and types
of solid wastes that are expected to be received.
The designer outlines volume requirements, site
improvements (clearing of the land, construction of
roadways and buildings, fencing, utilities), and all
the equipment necessary for day-to-day operations
of the specific landfilling method involved. He also
provides for controlling water pollution and the
movement of decomposition gas. The sanitary land-
fill designer should also recommend a specific use
of the site after landfilling is completed. Finally, he
should determine capital costs and projected op-
erating expenditures for the estimated life of the
project.
Volume Requirements
If the rate at which solid wastes are collected
and the capacity of the proposed site are known, its
useful life can be estimated. The ratio of solid
waste to cover material volume usually ranges be-
tween 4:1 and 3:1; it is, however, influenced by the
thickness of the cover used and cell configuration.
If cover material is not excavated from the fill site,
this ratio may be compared with the volume of
compacted soil waste and the capacity of a site
determined (Figure 6). For example, a town having
a 10,000 population and a per capita collection rate
of 5 Ib per day must dispose of, in a year, 11 acre-ft
of solid waste if it is compacted to 1,000 Ib per cu
yd. If it were compacted to only 600 Ib per cu yd,
the volume disposed of in a year would occupy 19
acre-ft. The volume of soil required for the 1,000-lb
density at a solid waste-to-cover ratio of 4:1 would
be 2.75 acre-ft; the 600-lb density waste would
need 4.75 acre-ft. A density of 800 Ib per cu yd is
easily achievable if the compacting of a representa-
tive municipal waste is involved. A density of 1,000
Ib per cu yd can usually be obtained if the waste
is spread and compacted according to procedures
described in Chapter 6.
The number of tons to be disposed of at a pro-
posed sanitary landfill can be estimated from data
o
u 16
O 8 -
24 6 ,8 10
SOLID WASTE COLLECTED (Ib/capila/colendor day)
Figure 6. Determining the yearly volume of
compacted solid waste generated by a community of
10,000 people.
20
-------
2000
O
500
200 400 600 800
SOLID WASTE DISPOSED OF DAILY (tons)
600
40 80 120 160 200
SOLID WASTE DISPOSED OF DAILY (tons)
Figure 7. Determining the daily volume of com-
pacted solid waste generated by large communities.
recorded when solid wastes are delivered to disposal
sites. The daily volume of compacted solid waste
can then be easily determined for a large community
(Figure 7) or for a small community (Figure 8). The
volume of soil required to cover each day's waste is
then estimated by using the appropriate solid waste-
to-cover ratio.
The terms used to report densities at landfills
can be confusing. Solid waste density (field density)
is the weight of a unit volume of solid waste in
place. Landfill density is the weight of a unit volume
of in-place solid waste divided by the volume of
solid waste and its cover material. Both methods of
reporting density are usually expressed as pounds
per cubic yard, on an in-place weight basis, includ-
ing moisture, at time of the test, unless otherwise
stated.
Site Impovements
The plan for a sanitary landfill should prescribe
how the site will be improved to provide an orderly
and sanitary operation. This may simply involve the
clearing of shrubs, trees, and other obstacles that
could hinder vehicle travel and landfilling opera-
tions or it could involve the construction of build-
ings, roads, and utilities.
CLEARING AND GRUBBING. Trees and brush
that hinder landfill equipment or collection vehicles
must be removed. Trees that cannot be pushed over
should be cut as close as possible to the ground
so that the stumps do not hinder compaction or
obstruct vehicles. Brush and tall grass in working
areas can be rolled over or grubbed. A large site
should be cleared in increments to avoid erosion
Figure 8. Determining the daily volume of com-
pacted solid waste generated by small communities.
and scarring of the land. If possible, natural wind-
breaks and green belts of trees or brush should be
left in strategic areas to improve appearance and
operation. Measures for minimizing erosion and
sedimentation problems are outlined in the publica-
tion Community Action Guidebook for Soil Erosion
and Sediment Control.1
ROADS. Permanent roads should be provided
from the public road system to the site. A large site
may have to have permanent roads that lead from
its entrance to the vicinity of the working area.
They should be designed to support the anticipated
volume of truck traffic. In general, the roadway
should consist of two lanes (total minimum width,
24 ft), for two-way traffic. Grades should not ex-
ceed equipment limitations. For loaded vehicles,
most uphill grades should be less than 7 percent
and downhill grades less than 10. Road alignments
and pavement designs have been adequately dis-
cussed elsewhere.2'3 The initial cost of permanent
roads is higher than that of temporary roads, but
the savings in equipment repair and maintenance
could justify the building of permanent, on-site
roads.
Temporary roads are normally used to deliver
wastes to the working face from the permanent road
system, because the location of the working face is
constantly changing. Temporary roads may be con-
structed by compacting the natural soil present and
by controlling drainage or by topping them with a
layer of a tractive material, such as gravel, crushed
stone, cinders, broken concrete, mortar, or bricks.
Lime, cement, or asphalt binders may make such
roads more serviceable.
If fewer than 25 round trips per day to the
21
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landfill are expected, a graded and compacted soil
will usually suffice. More than 50 round trips per
day generally justifies the use of calcium chloride as
a dust inhibitor or such binder materials as soil
cement or asphalt. A base course plus a binder is
desirable if more than 100 to 150 round trips per day
are anticipated.
SCALES. Recording the weights of solid waste
delivered to a site can help regulate and control
the sanitary landfill operation as well as the solid
waste collection system that serves it.
The scale type and size used will depend on
the scope of the operation. Portable scales may
suffice for a small site, while an elaborate system
employing load cells, electronic relays, and printed
output may be needed at a large sanitary landfill.
Highly automated electronic scales and recorders
cost more than a portable, simple, beam scale, but
their use may often be justified, because they are
faster and more accurate. The platform or scale
deck may be constructed of wood, steel, or concrete.
The first type is the least expensive, but also the
least durable.
The scale should be able to weigh the largest
vehicle that will use the landfill on a routine basis;
30 tons is usually adequate. Generally, the platform
should be long enough to weigh all axles simulta-
neously. Separate axle-loading scales (portable ver-
sions) are the cheapest, but they are less accurate
and slower operating. The scale platform should be
10 by 34 ft to weigh most collection vehicles. A
50-ft platform will accommodate most trucks with
trailers.
The accuracy and internal mechanism of the
scale and the recording device should meet the
commercial requirements imposed by the State and
any other jurisdiction involved, particularly if user
fees are based on weight. Recommended scale re-
quirements have been outlined by the National
Bureau of Standards.4
Since weights are seldom recorded closer than
to the nearest tenth of a ton and most applied loads
are between 8 and 14 tons, a scale accuracy of
±1.0 percent is acceptable. All scales should be
periodically checked and certified as to standard
accuracy.
Both mechanical and electronic scales should
be tested quarterly under load. The inspection
should include: (1) checking for a change in indi-
cated weight as a heavy load is moved from the
front to the back of the scale; (2) observing the
action of the dial during weighing for an irregularity
or "catch" in its motion; (3) using test weights.
BUILDINGS. A building is needed for office
space and employee facilities at all but the smallest
landfill; it can also serve as a scale house. Since a
landfill operates in wet and cold weather, some pro-
tection from the elements should be provided. Opera-
tional records may also be kept at a large site.
Sanitary facilities should be provided for both land-
fill and collection personnel. A building should also
be provided for equipment storage and maintenance.
Buildings on sites that will be used for less
than 10 years should be temporary types and, pref-
erably, be movable. The design and location of all
structures should consider gas movement and dif-
ferential settlement caused by the decomposing
solid waste.
UTILITIES. All sanitary landfill sites should have
electrical, water, and sanitary services. Remote sites
may have to extend existing services or use accept-
able substitutes. Portable chemical toilets can be
used to avoid the high cost of extending sewer lines,
potable water may be trucked in, and an electric
generator may be used instead of having power
lines run into the site.
Water should be available for drinking, fire
fighting, dust control, and employee sanitation. A
sewer line may be called for, especially at large
sites and at those where leachate is collected and
treated with domestic wastewater. Telephone or
radio communications are also desirable.
FENCING. Peripheral and litter fences are com-
monly needed at sanitary landfills. The first type is
used to control or limit access, keep out children,
dogs, and other large animals, screen the landfill,
and delineate the property line. If vandalism and
trespassing are to be discouraged, a 6-ft high fence
topped with three strands of barbed wire projecting
at a 45° angle is desirable. A wooden fence or a
hedge may be used to screen the operation from
view.
Litter fences are used to control blowing paper
in the immediate vicinity of the working face. As a
general rule, trench operations require less litter
fencing because the solid waste tends to be con-
fined within the walls of the trench. At a very windy
trench site, a 4-ft snow fence will usually suffice.
Blowing paper is more of a problem in an area
operation; 6- to 10-ft litter fences are often needed.
Some litter fences have been specially designed
and fabricated (Figure 9). Since the location of the
working face shifts frequently, litter fences should
be movable.
Control of Surface Water
Surface water courses should be diverted from
the sanitary landfill. Pipes may be used in gullies,
ravines, and canyons that are being filled to trans-
mit upland drainage through the site and open
channels employed to divert runoff from surround-
22
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Figure 9. Specially designed and fabricated litter-control fences are often used near the working face of
sanitary landfill.
ing areas (Figure 10). Sump pumps may also be
used. Because of operating and maintenance re-
quirements, the use of mechanical equiment for
water control is, however, strongly discouraged
unless the control is needed only temporarily. If
trenches or depressions are being filled, collection
sumps and pumps may be used to keep them from
flooding. Equipment sizes can be determined by
analyzing storm and flood records covering about
a 50-year period. Counseling and guidance in plan-
ning water management measures are available
through local soil conservation districts upon re-
quest. A landfill located in a flood plain should be
protected by impervious dikes and liners. The top
of the dike should be wide enough for maintenance
work to be carried out and may be designed for
use by collection and landfill vehicles.
The top cover material of a landfill should be
graded to allow runoff of rainfall. The grade of the
cover will depend on the material's ability to resist
erosion and the planned use of the completed site.
Portable or permanent drainage channels may be
Upland drainage (low
\
Proposed landfill
SECTION
Figure 10. Plan and section views of the use of a diversion ditch to transmit upland drainage around a
sanitary landfill.
23
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constructed to intercept and remove runoff water.
Low-cost, portable drainage channels can be made
by bolting together half-sections of corrugated steel
pipes. Surface water that runs off stockpiled cover
material may contain suspended solids and should
not be allowed to enter watercourses unless it has
been ponded to remove settleable solids.
Ground water Protection
It is a basic premise that groundwater and the
deposited solid waste not be allowed to interact.
It is unwise to assume that a leachate will be diluted
in groundwater because very little mixing occurs in
an aquifer since the groundwater flow there is usual-
ly laminar.
When issuing permits or certificates, many
States require that groundwater and deposited solid
wastes be 2 to 30 ft apart. Generally, a 5-ft separa-
tion will remove enough readily decomposed organics
and coliform bacteria to make the liquid bacteriolog-
ically safe.5'6 On the other hand, mineral pollutants
can travel long distances through soil or rock forma-
tions. In addition to other considerations, the sani-
tary landfill designer must evaluate the: (1) current
and projected use of the water resources of the area;
(2) effect of leachate on groundwater quality; (3)
direction of groundwater movement; (4) interrela-
tionship of this aquifer with other aquifers and sur-
face waters.
Groundwater mounds, rises in the piezometric
level of an aquifer in a recharge area, have been
found at several landfills.7 The mounds are reported
to be up to 5 ft above the surrounding groundwater
level, and they have intersected deposited solid
waste. The investigators believe the water table
probably rose because: (1) the permeability of the
landfill's soil boundary decreased as a result of
excavation and reworking; (2) more water infiltrated
through the cover material and solid waste than
through the undisturbed soils of the surrounding
area.7
If a groundwater mound intersects the solid
waste, leachate will undoubtedly enter the ground-
water and may emerge as a spring around the toe
of the fill where the groundwater table intersects
the ground surface. Both surface and groundwaters
may, therefore, be endangered if a mound forms.
An impermeable liner may be employed to con-
trol the movement of fluids. One of the most com-
monly used is a well-compacted natural clay soil,
usually constructed as a membrane 1 to 3 ft thick.
It must, however, be kept moist. If sufficient clay
soil is not available locally, natural clay additives,
such as montmorillonite, may be disked into it to
form an effective liner. The use of additives requires
evaluation to determine optimum types and
amounts.
Since synthetic liners have been used to
construct wastewater-holding-and-treatment ponds,
they may have an application in solid waste disposal
operations. They are usually made of butyl rubber,
polyethylene, or polyvinyl chloride and are installed
in multiple layers. (If the movement of both gas
and leachate is to be controlled, polyvinyl chloride
should work better than polyethylene because it is
less permeable by gas.) The membranes must be
put down carefully to avoid punctures, and layers of
soil (usually sand) must be placed on both sides of
them. Asphalt liners, which have been used to re-
duce seepage from canals and ditches, may also
have an application in a solid waste disposal opera-
tion.
The use of an impermeable barrier requires that
some method be provided for removal of the con-
tained fluid. If a natural ravine or canyon is involved,
the removal point should be the downstream end
of the filled area. The fluid in a bowl-shaped liner
could be pumped by a well or series of wells or
it could exit through gravity outlets in the bottom
of the liner. In the latter case, the pipes should be
sloped ys to 14 in. per ft.
It is often possible to permanently or tempo-
rarily lower the groundwater in free-draining, gravel-
ly, and sandy soils. Drains, canals, and ditches are
frequently used to intercept the groundwater and
channel it to surface water or recharge area at a
lower elevation. Doing this generally requires that
the designer have a thorough knowledge of the soil
permeabilities and the groundwater flow system in
the area. It is inadvisable to use temporary methods,
such as wells, to lower the water table because it
will rise after pumping ceases, and the waste will be
inundated. It is well to recognize that highly perme-
able soils that can be readily drained by ditching or
pumping will offer equally little resistance to the
movement of leachate from the decomposing solid
waste. Even though groundwater can be kept from
coming into direct contact with the solid waste, in
most climates infiltrated surface water will probably
enter the solid waste eventually, cause leaching,
and then percolate through the underlying porous
soil to enter the lowered groundwater. It is advis-
able, therefore, to view sites in highly permeable
material with extreme caution.
Little work has been done to determine the
types and costs of leachate treatment. Analysis of
leachate samples from a few landfills and labora-
tory lysimeters indicates that leachate is a complex
liquid waste and has variable characteristics. Since
most of the contaminants in leachate are water solu-
ble, conventional biological and chemical treatment
24
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methods are probably required and, hopefully, will
prove effective.
To help establish if a landfill is creating a
groundwater and surface water pollution problem,
a series of observation wells and sampling stations
can be used to periodically monitor the water quality.
Data on the upstream or uncontaminated water and
downstream water quality are necessary to evaluate
the pollution potential.
Gas Movement Control
An important part of sanitary landfill design is
controlling the movement of decomposition gases,
mainly carbon dioxide and methane. Traces of hy-
drogen sulfide and other odorous gases may also be
involved.
Methane (CH4) is a colorless, odorless gas that
is highly explosive in concentrations of 5 to 15 per-
cent when in the presence of oxygen. In a few in-
stances, methane gas has moved from a landfill
and accumulated in explosive concentrations in
sewer lines and nearby buildings. Gas from landfills
has also killed nearby vegetation, presumably by
Slope
. Slope
Vented gas
I Ł
Figure 11. Gravel vents or gravel-filled trenches
can be used to control lateral gas movement in a
sanitary landfill.
excluding oxygen from the root zone. Carbon dioxide
(C02) is also a colorless, odorless gas, but it does
not support combustion. It is approximately 1.5
times as heavy as air and is soluble in water. The
C02 reacts to a limited extent to form carbonic acid
(H2C03), which can dissolve mineral matter, partic-
ularly carbonates, in refuse, soil, and rock. If this
occurs, the mineral content or hardness of the water
increases, as has been noted at wells located near
landfills and dumps.
In general, no problems arise when landfill gas
can disperse into the atmosphere. If the fill has a
relatively impermeable cover, however, the methane
will try to vent into the atmosphere by moving
laterally through a more permeable material.
The natural soil, hydrologic, and geologic condi-
tions of the site may provide control of gas move-
ment. If not, methods based on controlling gas
permeability can be constructed. The following have
been used or are considered possible.
PERMEABLE METHODS. Lateral gas movement
can be prevented by using a material that is—
under all circumstances—more permeable than the
surrounding soil; gravel vents or gravel-filled trench-
es have been employed (Figure 11). Preferably, the
trenches should be somewhat deeper than the fill
to make sure they intercept all lateral gas flow. The
filter material should be graded to avoid infiltration
and clogging by adjacent soil carried in by water.
If possible, the trench should be built so that it
drains naturally; field tile is often placed in the
bottom of the trench. The surface of gravel trenches
should be kept free of soil and vegetation, because
they retain moisture and hinder venting.
In another method, vent pipes are inserted
through a relatively impermeable top cover (Figure
12). Collecting laterals placed in shallow gravel
trenches within or on top of the waste can be con-
nected to the vertical riser. The sizes and spacings
required have not been established, but they depend
on the rate of gas production, total weight of solid
waste, and the gas permeability of both the cover
and the surrounding soil. In some cases, vertical
risers have been used to burn off the gas. Pipe
vents should not be located near buildings, but if
this is unavoidable, they should discharge above
the roof line.
Pumped exhaust wells may be used for gas
venting. In this method, pipe vents are attached to
the line of a suction pump to create differential
driving pressure for gas movement. This method is
costly and requires frequent maintenance.
IMPERMEABLE METHODS. The movement of
gas through soils can be controlled by using materials
that are more impermeable to it than the surround-
ing soil. An impermeable barrier can be used to
25
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Vented gas
Vegetation
Final cover material
w*p»
mi- o>ov.r
Perforated lateral
Cell
Figure 12. Gases are sometimes vented out of
a sanitary landfill via pipes that are inserted through
a relatively impermeable top cover and are connected
to collecting laterals placed in shallow gravel trenches
within or on top of the waste.
contain the gas and vent it through the top cover
or simply to block the flow of gas.
The most common method, and possibly the
most practical, calls for the use of compacted clay.
The material must, however, be kept moist, other-
wise it could shrink and crack. (Other fine grained
soils may also be used, with the same stipulation.)
The clay can be placed as a liner in an excavation
or installed as a curtain wall to block underground
gas flow (Figure 13). A clay layer 18 to 48 in.
thick is probably adequate, but it should be con-
tinuous and not be penetrated by solid waste or out-
croppings of the surrounding soil or rocks. The liner
should be constructed as the fill progresses, because
prolonged exposure to air will dry the clay and cause
it to shrink and crack.
The use of synthetic membranes was described
in the section on Groundwater Protection.
Sanitary Landfilling Methods
The designer of a sanitary landfill should pre-
scribe the method of construction and the proce-
dures to be followed in disposing of the solid waste,
because there is no "best method" for all sites. The
method selected depends on the physical conditions
involved and the amount and types of solid waste
to be handled.
The two basic landfilling methods are trench
and area; other approaches are only modifications. In
general, the trench method is used when the ground-
water is low and the soil is more than 6 ft deep.
It is best employed on flat or gently rolling land.
The area method can be followed on most topog-
raphies and is often used if large quantities of solid
V
Clay barrier
\ Proposed | final | grade
I I I
' Vented gas I I
Clay barrier
/ ,
Figure 13. Clay can be placed as a liner in an excavation or installed as a curtain wall to block underground
gas flow.
26
-------
^XT-•.:•.:: cover J^
-------
-j-^«fiosMi^&^
^*ŁL**Ł*"
MM^4*^!^M^Ki^ij4^^%^^a.-_,
Figure 15. In the trench method of sanitary landfilling, the collection truck deposits its load into a trench
where a bulldozer spreads and compacts it. At the end of the day, the trench is extended, and the excavated
soil is used as daily cover material.
cover may be stockpiled and later used as a cover
for an area fill operation on top of the completed
trench fill.
Cohesive soils, such as glacial till or clayey
silt, are desirable for use in a trench operation be-
cause the walls between the trenches can be thin
and nearly vertical. The trenches can, therefore, be
spaced very closely. Weather and the length of time
the trench is to remain open also affect soil stabil-
ity and must be considered when the slope of the
trench walls is being designed. If the trenches are
aligned perpendicularly to the prevailing wind, this
can greatly reduce the amount of blowing litter.
The bottom of the trench should be slightly sloped
for drainage, and provision should be made for
surface water to run off at the low end of the trench.
Excavated soil can be used to form a temporary
berm on the sides of the trench to divert surface
water.
The trench can be as deep as soil and ground-
water conditions safely allow, and it should be at
least 'twice as wide an any compacting equipment
that will work in it. The equipment at the site may
excavate the trench continuously at a rate geared
Figure 16. In the area method of sanitary landfilling, a bulldozer spreads and compacts the waste on the
natural surface of the ground, and a scraper is used to haul the cover material at the end of the day's operations.
28
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to landfilling requirements. At small sites, excava-
tion may be done on a contract basis.
AREA METHOD. In this method, the waste is
spread and compacted on the natural surface of
the ground, and cover material is spread and com-
pacted over it (Figure 16). The area method is used
on flat or gently sloping land and also in quarries,
strip mines, ravines, valleys, or other land depres-
sions.
COMBINATION METHODS. A sanitary landfill
does not need to be operated by using only the area
or trench method. Combinations of the two are possi-
ble, and flexibility is, therefore, one of sanitary land-
filling's greatest assets. The methods used can be
varied according to the constraints of a particular
site.
One common variation is the progressive slope
or ramp method, in which the solid waste is spread
and compacted on a slope. Cover material is ob-
tained directly in front of the working face and
compacted on the waste (Figure 17). In this way,
a small excavation is made for a portion of the next
day's waste. This technique allows for more effi-
cient use of the disposal site when a single lift is
constructed than the area method does, because
cover does not have to be imported, and a portion
of the waste is deposited below the original surface.
Both methods might have to be used at the
same site if an extremely large amount of solid
waste must be disposed of. For example, at a site
with a thick soil zone over much of it but with only
a shallow soil over the remainder, the designer
would use the trench method in the thick soil
zone and use the extra spoil material obtained to
carry out the area method over the rest of the
site. When a site has been developed by either
method, additional lifts can be constructed using
the area method by having cover material hauled in.
The final surface of the completed landfill
should be so designed that ponding of precipitation
does not occur. Settlement must, therefore, be con-
sidered. Grading of the final surface should induce
drainage but not be so extreme that the cover
material is eroded. Side slopes of the completed
surface should be 3 to 1 or flatter to minimize
maintenance.
Finally, the designer should consider complet-
ing the sanitary landfill in phases so that portions of
it can be used as parks and playgrounds, while
other parts are still accepting solid wastes.
Summary of Design Considerations
The final design of a sanitary landfill should
describe in detail: (1) all employee and operational
facilities; (2) operational procedures and their se-
quence, equipment, and manpower requirements;
(3) the pollution potential and methods of control-
Figure 17. In the progressive slope or ramp method of sanitary landfilling, solid waste is spread and com-
pacted on a slope. Cover material is obtained directly in front of the working face and compacted on the waste.
29
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ling it; (4) the final grade and planned use of the
completed fill; (5) cost estimates for acquiring,
developing, and operating the proposed site.
The designer should also provide a map that
shows the location of the site and the area to be
served and a topographic map covering the area
out to 1,000 ft from the site. Additional maps and
cross-sections should also be included that show
the planned stages of filling (startup, intermediate
lifts, and completion). They should present the de-
tails of:
1. Roads on and off the site;
2. Buildings;
3. Utilities above and below ground;
4. Scales;
5. Fire protection facilities;
6. Surface drainage (natural and con-
structed) and groundwater;
7. Profiles of soil and bedrock;
8. Leachate collection and treatment
facilities;
9. Gas control devices;
10. Buildings within 1,000 ft of proper-
ty (residential, commercial, agri-
cultural);
11. Streams, lakes, springs, and wells
within 1,000 ft;
12. Borrow areas and volume of ma-
terial available;
13. Direction of prevailing wind;
14. Areas to be landfilled, including
special waste areas, and limitations
on types of waste that may be dis-
posed of;
15. Sequence of filling;
16. Entrance to facility;
17. Peripheral fencing;
18. Landscaping;
19. Completed use.
REFERENCES
1. Community action guidebook for soil erosion and sediment control. The
National Association of Counties Research Foundation, 1970. 66 p.
2. HAY, W. H. Transportation engineering. John Wiley & Sons, Inc. New York,
1961. 505 p.
3. OGLESBY, C. H., and L. I. HEWES. Highway engineering. John Wiley & Sons,
Inc. New York, 1963.
4. U.S. National Bureau of Standards. Specifications, tolerances, and other
technical requirements for commercial weighing and measuring
devices adopted by National Conference on Weights and Measures.
Handbook 44. 3d ed. Washington, U.S. Government Printing Office,
1965. 178 p.
5. California State Water Quality Control Board. Waste water reclamation in
relation to ground water pollution. Publication No. 24. Sacramento,
1953.
6. ANDERSON, D. R., W. D. BISHOP, and H. F. LUDWIG. Percolation of citrus
wastes through soil. In Proceedings; 21st Industrial Waste Conference,
May 3-5, 1966. Lafayette, Ind., Purdue University, p. 892-901.
7. HUGHES, G. M., R. A. LANDON, and R. N. FARVOLDEN. Hydrogeology of
solid waste disposal sites in northeastern Illinois; a final report on a
solid waste demonstration grant project. Washington, U.S. Govern-
ment Printing Office, 1971. 154 p.
30
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sanitary landfill operation
The best designed disposal facility will be of
little value unless it is constructed and operated as
prescribed. This is especially true of a sanitary
landfill because it is under construction up to the
day the last particle of solid waste is disposed of.
Constructing the sanitary landfill on a daily basis
in accordance with the design should be unequivo-
cally required in an operations plan.
An operations plan is essentially the specifi-
cation for construction and it should contain all
items required to construct the sanitary landfill.
It should describe: (1) hours of operation; (2) mea-
suring procedures; (3) traffic flow and unloading
procedures; (4) designation of specific disposal
areas and methods of handling and compacting
various solid wastes; (5) placement of cover ma-
terial; (6) maintenance procedures; (7) adverse
weather operations; (8) fire control; (9) litter con-
trol; (10) salvaging operations, if permitted.
Proper operation calls for drawing up a com-
prehensive plan that spells out routine procedures
and anticipates abnormal situations. It must also
provide continuity of activities even when personnel
changes occur. New supervisors and personnel
responsible for solid waste disposal must know
what is being done at the landfill and why. The plan
must, however, remain open for revision when
necessary. Changes should be noted, and the ra-
tionale behind them explained. New personnel will
benefit from the experience of others, and con-
tinuity of operations will be preserved.
The plan should also be used as a tool in
training employees, defining their jobs, and giving
them an insight into the work of others. In this
manner, the employee will more fully understand
the overall operation, and he may be able to per-
form other duties in an emergency.
Hours of Operation
The hours a sanitary landfill operates depend
mainly on when the wastes are delivered, and gen-
erally this is done during normal working hours.
In large cities, however, waste collection systems
sometimes operate 24 hr a day. In this case, a site
should not be located in a residential area. The usual
landfill is open 5 to 6 days a week and 8 to 10 hr
a day.
The hours of operation should be posted on a
sign at the landfill entrance. It should also indicate:
what wastes are not accepted; fees charged; and
the name, address, and telephone number of the
operating body (sanitation district or private com-
pany). All this information must be kept current.
Fees are usually levied on a cost-per-ton basis for
large loads and on a fee basis for small amounts
brought to the site by homeowners. The sanitary
landfill should be open only when operators are
on duty. If it is anticipated that waste will be brought
to a disposal site at other times, a large container
should be placed outside the site entrance.
Weighing the Solid Waste
The efficiency of filling and compacting opera-
tions can be adequately judged if the amount of
solid waste delivered, the quantity of cover material
used, and the volume occupied by the landfilled
solid waste and cover are known. (Weighing is the
most reliable means of measurement.) These values
are also used to determine the density of the fill
and to estimate the amount of settlement that will
probably occur. Weight and volume data can also
be used in designing new landfills and predicting
31
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the remaining capacity of currently operating land-
fills.
The number of vehicles that can be weighed
in a unit of time will vary. An experienced weigh-
master is able to record manually, for short periods
of time, the net weight and types of material de-
livered at a rate of 60 trucks per hr, but it is
extremely taxing to maintain this pace for long
periods. A highly automated weighing procedure
can easily accommodate over 60 trucks per hr,
record more data, require less supervision, and be
more accurate. Landfills disposing of 1,000 tons or
more per day will usually require two or more auto-
matic scales. Truck scales require little maintenance
if inspected and maintained as recommended by
their manufacturers.
Although a seemingly simple operation, weigh-
ing presents many problems. To ensure that all
trucks are weighed, vehicle-handling controls and
accounting techniques must be developed. Tech-
niques being used include a two-gate system (one
at the front and one at the back of the scale) that
locks a truck on the scale until weighed, one-way
exit barricades, signal lights, curbing, alarms, and
numerous automated recording devices.
If a truck is not properly positioned on the
platform (one or more axles off) the weight recorded
will be wrong. Suitable curbing, markings, elevated
transverse bumps, or extra long scales can reduce
or prevent unintentional misplacement of vehicles
on the scale.
Dirt, water, snow, and ice may accumulate
on and under the deck of the scale and cause it to
wear and rust, lead to hazardous driving conditions,
and generate weighing errors.
Traffic Flow and Unloading
Traffic flow on the site can affect the efficiency
of daily operations. Traffic should be allowed to
bypass the scale only if it is inoperative. Haphazard
routing between the scale and the disposal area can
lead to indiscriminate dumping and cause accidents.
Pylons, barricades, guardrails, and traffic signs can
be used to direct traffic. Large sites may need posted
maps to direct drivers. If separate working areas are
established for different types of wastes, signs
should be used to direct drivers to the appropriate
disposal areas.
Wastes are delivered to a landfill in vehicles
that range from automobiles to large transfer trail-
ers. Operationally, they comprise groups that are
unloaded manually or mechanically. The two cate-
gories are established because of the difference in
time it takes to unload them at the working face.
If large numbers of manually unloaded vehicles
must be handled, special procedures may be neces-
sary.
Mechanically discharging vehicles include dump
trucks, packer-type collection trucks, tank trucks,
and open or closed body trucks equipped with a
movable bulkhead that requires the use of a crawler
dozer or loader. These vehicles are capable of
rapidly discharging their loads and should be routed
directly to the working face without delay.
Manually discharging vehicles take more time
to unload and should not be permitted to slow the
unloading of vehicles that can discharge mechan-
ically. Many of the drivers will not be familiar with
the landfill operation and will require close super-
vision. If a large number of manually discharging
vehicles is involved, a separate unloading area may
be necessary to avoid delaying other vehicles.
Scavenging should not be permitted, and no
vehicle should be left unattended. Waste should be
deposited at the toe of the working face, because
it can be compacted better there since it is worked
up the slope rather than down. If it is necessary to
discharge solid wastes at the top of the slope, as
in a narrow trench operation, telephone poles or
similar objects should be emplaced to warn drivers
that they are near its edge. The unloading area
should be as level as practical for dump trucks and
other vehicles having high centers of gravity in the
raised position.
Handling of Wastes
Wastes come from residences, commercial
establishments, institutions, municipal operations,
industries, and farms. Some may require special
methods of handling and burial. The landfill de-
signer should know all the types that will likely
be involved and make provision for their disposal.
Materials that cannot be safely buried should be
excluded.
RESIDENTIAL, COMMERCIAL, AND INDUS-
TRIAL PLANT WASTES. These wastes (exclusive of
process wastes discussed later) are usually highly
compactible. They contain a heterogeneous mixture
of such materials as paper, cans, bottles, cardboard
and wooden boxes, plastics, lumber, metals, yard
clippings, food waste, rocks, and soil. When exposed,
boxes, plastic and glass containers, tin cans, and
brush can be compressed and crushed under relative-
ly low pressure. In a landfill, however, these items are
incorporated within the mass of solid waste, which
acts as a cushion and often bridges, thus protecting
the relatively low-strength materials from being
crushed under the load of the compaction equipment.
Cushioning and bridging can be reduced and
greater volume reduction achieved if the waste is
32
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spread in layers less than 2 ft deep and is then
compacted by tracked, rubber-tired, or steel-wheeled
vehicles that pass over it 2 to 5 times. Solid waste
that contains a high percentage of brush and yard
clippings requires the expenditure of more com-
pactive effort. If entire loads of these items are
received, they should be spread and compacted
near the bottom of the cell so that less resilient
wastes can be compacted on top.
The equipment operator should try to develop
the working face on a slope between 20° and 30°
(Figure 18). Waste is spread against the slope, and
the machine moves up and down it, thus tearing
and compacting the waste and eliminating voids.
The equipment operator should make passes until
he no longer can detect that the surface of the
waste layer is being depressed more than it is
rebounding.
BULKY WASTES. Bulky wastes include car
bodies, demolition and construction debris, large ap-
pliances, tree stumps, and timbers. Significant vol-
ume reduction of construction rubble and stumps by
compaction cannot be achieved, but car bodies, furni-
ture, and appliances can be significantly reduced in
volume. A small crawler dozer (110 HP and 20,000
Ib. or less) has greater difficulty in compacting wash-
ing machines and auto bodies than would heavy ma-
chines, but some volume reduction can be achieved.
Such items should be crushed on solid ground and
then pushed onto the working face, near the bottom
of the cell or into a separate disposal area. Once in
place, most bulky items do not degrade (at least not
at a rate comparable to surrounding refuse). Conse-
quently, if bulky items are incorporated into degrad-
able wastes, uneven settlement will result. Special
areas for bulky items should be identified on the
final plan of the completed site. Even though bulky
wastes do not usually contain putrescibles, they
should be completely covered at the end of each
operating day to eliminate harborage for rats and
other pests.
Selected loads of demolition and construction
:CTPP l "•'• Unload
•.jl Cr I ... - .. -.
•:-.'. '.•'•;.; -.';•: • solid waste
.''.'•••;•':;• :•:'.'•.".'• at toe of slope
STEP 2 ''..-..• Spread in thin layers
::'•.':•.•'•.'.;.•.•.'. (approximately 2 feet)
'•'••^Ł-'"-'/.'.':. Compact by running tractor ..;-.V.
.STEP 3 ...: over waste layer 2 to 5 times :'•'"•';"'
Figure 18. Cushioning and bridging can be reduced and greater volume reduction achieved if the waste is
spread in layers less than 2 ft deep and is then compacted by a tracked, rubber-tired, or steel-wheeled vehicle
that passes over it 2 to 5 times. The equipment operator should try to develop the working face on a slope be-
tween 20 and 30 degrees.
33
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debris—broken concrete, asphalt, bricks, and plas-
ter—can be stockpiled and used to build on-site
roads.
INSTITUTIONAL WASTES. Solid wastes from
schools, rest homes, and hospitals are usually highly
compactible and can often be handled in the same
manner as residential and commercial wastes and
are often delivered along with them. If hospital
wastes are delivered separately, they should be
spread immediately, compacted, and enclosed with
another layer of waste or a cover material because
they could contain pathogenic organisms. Pathologi-
cal wastes are usually disposed of in a special in-
cinerator, but if accepted, they should be buried
immediately under 1 ft of cover material. Some
States have restrictions on the way such wastes
are buried, and pertinent State laws should be
consulted.
DEAD ANIMALS. Dead birds, cats, dogs, horses,
and cows are occasionally delivered to sanitary
landfills. The burial method is covered by law in
most States. Some require that they be immediately
incorporated into the landfill and covered, others
demand that they be placed in a pit and covered
with lime. In general, small animal corpses can be
safely disposed of if placed in a landfill along with
other wastes and immediately covered. Very large
animals are usually dismembered so they can be
transported to the disposal site. They are then
placed in a pit and covered with 2 ft of compacted
soil; this should be graded periodically to avoid
ponding and settlement, which could be appreciable.
INDUSTRIAL PROCESS WASTES. Because of
the wide variety of industrial process wastes and their
different chemical, physical, and biological character-
istics, it is difficult to generalize about handling
them. The best source of information concerning
their characteristics is the industries that produce
them. It is extremely important to evaluate the influ-
ence of these wastes on the environment. If an
industrial waste is determined to be unsuitable for
disposal at the landfill, it should be excluded and
the respective industries notified. Another important
factor is the health and safety of landfill personnel.
Industrial wastes delivered to a landfill may
be in the form of a liquid, semi-liquid, films, sheets,
granules, shavings, turnings, powders, and defec-
tively manufactured products of all shapes and
sizes. Whether or not these are disposed of in the
sanitary landfill depends on the environmental con-
ditions of the site and whether or not they are
chemically and biologically stable. They should not
be allowed to pollute surface water or groundwater.
Liquids and semi-liquids, if deemed safe to
place in a landfill, should be admixed with relatively
dry, absorbent solid waste or they may be disposed
of in a pit well above the groundwater table. The
pit should be fenced and the gate locked to prevent
unauthorized access; its location should be recorded
in the final plan of the completed site.
Films and other light, fluffy, easily airborne
materials can be a nuisance at the working face,
and they should be covered immediately when de-
posited there. Spraying them with water may be
helpful, but the detrimental effects of adding water
should be considered.
Large sheets of metal, plastic, or wood can
also be nuisances at the working face. The equip-
ment operator should align the sheets parallel to
one another. Random placement leads to large
voids, poor compaction, and substantial settlement
of the completed landfiH.
Granules, shavings, turnings, and powders can
be health hazards to operating personnel, nuisances
if they become airborne, and very abrasive or cor-
rosive to the landfill equipment; they should be
covered immediately.
The workers may have to wear face masks,
goggles, or protective clothing to avoid respiratory,
eye, or skin ailments.
Defectively manufactured products are de-
livered to the landfill to keep them off the market.
These wastes should be incorporated into the sani-
tary landfill immediately so that drivers, helpers,
and others at the working face are not tempted to
engage in scavenging. Their doing so would violate
the manufacturer's trust and, even more important-
ly, would expose them to injury.
VOLATILE AND FLAMMABLE WASTES. Some
wastes, such as paints, paint residues, dry cleaning
fluids, and magnesium shavings, are volatile or flam-
mable. They may be in powder, solid, or liquid form,
and they usually derive from industrial processing or
are commercial wastes. If they are not highly flam-
mable or volatile, they may be admixed with other
wastes, otherwise they should be excluded from
the fill or quickly disposed of in a separate area
at the site. If the latter step is taken, the area
should be clearly marked with warning signs, and
its exact location recorded in the final plan of the
completed site. Under no circumstances should
smoking or open flames be allowed in the vicinity
of volatile or flammable wastes when they are being
disposed of.
WATER AND WASTEWATER TREATMENT PLANT
SLUDGES. Dewatered sludges received from water
treatment plants and dewatered digested sludges
received from wastewater treatment plants can be
disposed of at a sanitary landfill. In most cases, they
can be placed in the regular part of the fill, but they
should be covered immediately. If their moisture
content is relatively high, the sludges should be
34
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mixed with the other wastes before being covered
to prevent localized leaching. Raw sewage sludges
and septic tank pumpings should not be disposed
of at a sanitary landfill.
INCINERATOR FLY ASH AND RESIDUE. Fly ash
is a fine particulate material that has been removed
from combustion gases. As more stringent air
pollution control regulations are enforced, the quan-
tity of fly ash that must be disposed of is expected
to increase. Fly ash may be moist or dry, depending
on how it is separated from the gas stream. If it is
dry, water may have to be added to it so that it
does not become airborne and create a nuisance.
Covering should take place immediately. Residue
is the solid material that remains after a combustion
process ends. The amount of decomposable organics
present in incinerator residue varies widely, but few
incinerators produce a residue low enough in de-
composable organics to allow it to be used as a
daily cover material. When the residue dries, the
fines can create a dust problem. Because of its
moisture and food content, residue may have a
foul odor and attract flies, birds, and rodents.
Residue of this nature should be incorporated into
a sanitary landfill.
PESTICIDE CONTAINERS. Pesticide containers
may be delivered to landfills in agricultural areas. If
they are empty, they can be crushed by the landfill
equipment and disposed of along with other solid
wastes. If they are full or only partially empty, they
should be excluded from the sanitary landfill and
stored with proper inspection to avoid environmental
insult, pending final detoxification and disposal by
incineration or pyrolysis under carefully controlled
time and temperature conditions.
ANIMAL MANURE. Another waste originating
primarily in agricultural areas is animal manure,
which often contains a large amount of hay or bed-
ding. If the waste is not wet enough to flow, it can be
placed in the regular part of the fill but should be
covered immediately. If the moisture content is
high, the manure should be mixed with dry waste
and immediately covered.
RADIOACTIVE WASTES AND EXPLOSIVES.
Landfills do not accept radioactive wastes.* If any are
detected in a delivery, the operator should isolate
the wastes, truck, and driver and contact the proper
health authorities. Explosives are rarely delivered
to a disposal site, and should be handled with
extreme caution when they are. If they are accepted,
the operations plan should contain a provision that
explicitly outlines handling procedures, and a demo-
litions expert should be consulted if possible. The
exact location of the waste should be recorded on
TABLE 6
Application of Cover Material
Cover material
Daily
Intermediate
Final
Minimum
thickness
6 in.
1ft
2ft
Exposure
time*
0-7 days
7-365 days
> 365 days
' The length of time cover material will be exposed to
erosion by wind and rain.
the final plan of the completed site, and security
fencing and warning signs should be erected.
Placement of Cover Material
The operations plan should specify what soils
are to be used as cover material, where they are
to be obtained, and how they are to be placed over
the compacted solid waste. The first two specifica-
tions are determined by the landfill designer after
he has evaluated the soil investigation and the
functional requirements of the cover material. Cover
materials used at a sanitary landfill are classed as
daily, intermediate, and final; the classification de-
pends on the thickness of soil used. This is deter-
mined by its susceptibility to wind and water erosion
and its ability to meet certain functional require-
ments. Guides for using the different classes are
determined by the length of time the cover is to
be exposed to the elements (Table 6). In general,
if the cover is to be exposed for more than 1 week
but less than 1 year, intermediate cover should be
used. If the cover is to be exposed less than 1 week,
daily cover is sufficient, and if the cover is to be
exposed longer than 1 year final cover should be
used. All cover material should be well compacted.
Coarse grained soils can be compacted to 100 to
135 Ib per cu ft, fine grained soils to 70 to 120.*
DAILY COVER. The important control functions
of daily cover are vector, litter, fire, and moisture.
Generally, a minimum compacted thickness of 6
in. of soil will perform these functions. The cover
is applied to the compacted waste at least at the
end of each operating day. If possible, it should be
spread and compacted on the top and sideslopes
as construction of the cell progresses, thus leaving
only the working face exposed. At the end of the
* Radioactive wastes are disposed of under the auspices
of the U.S. Atomic Energy Commission.
* Unit dry weight of compacted soil at optimum moisture
content for Standard AASHO compactive effort.
35
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operating day, the working face is also covered.
No waste should be exposed, and the cover should
be graded to p /ent erosion and to keep water
from ponding.
INTERMEDIATE COVER. Functions of interme-
diate cover are the same as daily cover but include
gas control and possibly service as a road base. It is
applied in the same manner as daily cover, but the
minimum compacted depth recommended is 1 ft.
Periodic grading and compacting may be necessary
to repair erosion damage and to prevent ponding
of water. Cracks and depressions may develop be-
cause of moisture loss and settlement of the fill,
and periodic maintenance is required.
FINAL COVER. Final cover serves basically the
same functions as intermediate cover, but it must
also support vegetative growth. At a minimum, 2
ft of soil should be used, compacted into 6-in. thick
layers. Such factors as soil type and anticipated
use of the completed landfill may require more
than 2 ft.
Grading is extremely important, and grades
should be specified in the landfill design. The gen-
eral topographic layout of the completed landfill
surface is attained by carefully locating solid waste
cells, but the final cover is graded and compacted
to achieve the desired configuration. Water should
not be allowed to pond on the landfill surface and
grades should not exceed 2 to 4 percent to prevent
the erosion of cover material. Sideslopes should be
less than 1 vertical to 3 horizontal. Preferably, topsoil
from the site should be stockpiled and reserved for
placement on top of the final cover. Since the top-
soil will be seeded, it should not be highly com-
pacted.
Maintenance
A properly operated sanitary landfill is dis-
tinguished from an open dump by its appearance.
The effectiveness of pollution control measures also
depends on how well the landfill is maintained dur-
ing construction and after completion.
Dust is sometimes a problem, especially in
dry climates and if the soil is fine grained. Dust
can cause excessive wear of equipment, can be a
health hazard to personnel on the site, and can be
a nuisance if there are residences or businesses
nearby.
Dust raised from vehicular traffic can be tem-
porarily controlled by wetting down roads with water
or by using a deliquescent chemical, such as cal-
cium chloride, if the relative humidity is over 30
percent. Calcium chloride may be applied at a rate
of 0.4 to 0.8 Ib per sq yd and then be admixed
with the top 3 in. of the road surface. Frequent ap-
plications are usually required, because calcium
chloride is soluble in water and is readily leached
from the soil surface. Waste oils can also be used
as temporary dust palliatives. Periodic treatment
or multiple sprayings at a rate of 0.25 to 1.0 gal
per sq yd may be necessary. After several treat-
ments, a packed, oily soil crust usually develops
that has good resistance to traffic abrasion and is
moderately resistant to water. Good penetration by
the oil can be expected in more permeable soils.
Clayey soils or tightly knit surfaces may resist
penetration, in which case it may be desirable to
lightly scarify the surface, apply 0.25 to 0.5 gal of
oil per sq yd, and compact the surface. Waste oil,
water spraying, and calcium chloride treatment are
only temporary solutions; heavily traveled roads
should be covered with bituminous or cementing
materials to provide a more permanent surface.
One of the most important aspects of main-
tenance is litter control. A landfill operator who
permits litter to accumulate and spread from the
site is open to warranted public criticism. Public
acceptance of proposed sanitary landfills will be
easier if those under construction are properly main-
tained. Blowing litter can be kept at a minimum by
maintaining a small-size working face and covering
portions of the cell as they are constructed. Snow
fences can be positioned around the working face
to catch blowing paper and plastic, but unique wind
problems may make it necessary to fabricate spe-
cially designed fencing. All fences used should be
portable so that they can be kept near the working
face. Personnel should clean up litter periodically
every working day, especialy near the close of busi-
ness. The litter should be placed on the working
face before it is covered.
Equipment used at a landfill requires regular
maintenance, and the operations plan should estab-
lish a routine preventive maintenance program for
all equipment. Information used to develop this
program is available from the respective manufac-
turers.
A daily application of cover material prevents
problems associated with rats, flies, and birds.
These pests are rarely troublesome at a properly
operated sanitary landfill.
Rats are occasionally brought in along with the
solid waste delivered. When the waste is unloaded
the rats seek cover. They are then buried when the
waste is spread, compacted, and covered. Infre-
quently, rats escape and seek protection elsewhere.
If they then become a nuisance, they should be
killed by conducting a baiting program that is super-
vised by an experienced exterminator. Local inhabi-
tants must be informed of the baiting program,
signs must be erected, and children and pets must
36
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be kept away from the bait stations. If strong poi-
sons are used, guards should keep people away.
Generally, an anticoagulant poison should be used
over a two-to-three week period. When no more bait
is taken, the extermination program can be termi-
nated. Procedures for using and making poisoned
bait have been developed for employment at dis-
posal sites.1'3 In no case, however, should extermi-
nation procedures be substituted for daily cover.
Poisoning is rarely 100 percent effective, and it is
only a short-term solution.
If fly problems become severe in summer and
an insecticide is used, daily application is necessary,
because the insecticide particle must impinge on
the fly. Effective insecticides are malathion, dichlor-
vos, naled, dimethoate, Diazinon, fenthion, and
ronnel (Table 7). Application of cover material as
the cell is constructed may control flies without
using insecticides.
Birds that are sometimes attracted to landfills
can be a nuisance, a health hazard, and a danger
to low-flying aircraft. Various methods, such as
cannon fire, have been used to frighten the birds,
but they become familiar with the particular noise
and rapidly return. Falcons have been used with
varying success, but they apparently cannot con-
tend with seagulls. Recording the troublesome birds'
distress call and playing it back over a public
address system has also failed. The only way to
reduce the problem is to make each working face
as small as possible and to cover all wastes as
soon as feasible.
Weather Conditions
Weather can slow the construction of a sani-
tary landfill, and the operations plan should provide
detailed instructions on how to operate the landfill
during anticipated inclement periods.
In freezing weather, the greatest difficulty is
obtaining cover material. If the frost penetrates
below 6 in., crawler dozers or loaders equipped with
hydraulic rippers are needed to loosen the soil.
If several soils are available at the site, well-drained
soils, not as susceptible to freezing as those that
are poorly drained, should be reserved for use as
winter cover material. If the frost line goes more
than 1 ft below the surface, cover material should
be stockpiled beforehand. Calcium chloride can be
admixed into the soil to prevent freezing, or it can
be covered with tarpaulins or leaves; tarpaulins
should be dark to adsorb the sun's heat. If the
trench construction method is used, enough soil
should be excavated during warm months to handle
the wastes to be disposed of during freezing
weather. The trench bottom should be sloped to one
TABLE 7
Insecticides for Fly Control3
(Outdoor space sprays)
Insecticide
Approximate Ib per acre dosage
required for effective kills
(up to 200 ft)
Malathion
Dichlorvos
Naled
Dimethoate
Diazinon
Fenthion
Ronnel
0.6
0.3
0.1-0.2
0.1-0.2
0.3
0.4
0.4
end to collect rainfall, which should be pumped out
before it freezes.
Rain can cause operational problems. Roads
leading from all-weather access roads to the work-
ing face can become a quagmire and prevent col-
lection trucks from unloading. Roads leading to the
active working area should be passable in any*kind
of weather. Gravel, crushed stone, and construction
and demolition rubble may be applied to the surface.
Collection trucks that pick up mud on the site
should be cleaned before leaving it to keep them
from dirtying the public road system.
Fires
No burning of wastes is permitted at a sani-
tary landfill, but fires occur occasionally because
of carelessness in the handling of open flames or
because hot wastes are disposed of. The use of
daily cover should keep fire in a cell that is under
construction from spreading laterally to other cells.
All equipment operators should keep a fire extin-
guisher on their machines at all times, since it may
be able to put out a small fire. If the fire is too
large, waste in the buring area must be spread out
so that water can be applied. This is an extremely
hazardous chore, and water should be sprayed on
those parts of the machine that come in contact
with the hot wastes. The operations plan should
spell out fire-fighting procedures and sources of
water. All landfill personnel should be thoroughly
familiar with these procedures.
A collection truck occasionally arrives carrying
burning waste. It should not be allowed near the
37
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working face of the fill but be routed as quickly as
possible to a safe area, away from buildings, where
its load can be dumped and the fire extinguished.
Salvage and Scavenging
Salvaging usable materials from solid waste
is laudable in concept, but it should be allowed only
if a sanitary landfill has been designed to permit
this operation and appropriate processing and stor-
age facilities have been provided. All salvage pro-
posals must be thoroughly evaluated to determine
their economic and practical feasibility. Salvaging
is usually more effectively accomplished at the point
where waste is generated or at specially built plants.
The capital and operating costs of salvage operations
at a disposal site are usually high, even if it is
properly designed and operated. If salvaging is
practiced, it should be accomplished at a specially
designed facility away from the operating area.
Salvaging should never be practiced at the working
face.
Scavenging, sorting through waste to recover
seemingly valuable items, must be strictly pro-
hibited. Scavengers are too intent on searching to
notice the approach of spreading and compacting
equipment, and they risk being injured. Moreover,
some of the items collected may be harmful, such
as food waste, canned or otherwise; these items
may be contaminated. Vehicles left unattended by
scavengers interfere with operations at the fill.
REFERENCES
1. BRUNNER, D. R., S. J. HUBBARD, D. J. KELLER, and J. L. NEWTON. Closing
open dumps. [Washington, U.S. Government Printing Office], 1971.
19 p.
2. MALLIS, A. Handbook of pest control. 3d ed. New York, MacNair-Dorland
Company, Inc., 1960. p. 46.
3. Public health pesticides. Pest Control, 38(3):15-54, Mar. 1970.
38
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equipment
There is a wide variety of equipment available
for sanitary landfill operations. The types selected
will depend on the amount and kinds of solid waste
to be landfilled each day and on the operational
methods to be employed at a particular site. Since
money spent on equipment constitutes a large cap-
ital investment and accounts for a large portion of
operating costs, the selection should be based on
a careful evaluation of the functions to be performed
and the cost and ability of various machines to
meet the needs.
Equipment Functions
Sanitary landfill machines fall into three gen-
eral functional categories: (1) those directly in-
volved in handling waste; (2) those used to handle
cover material; (3) those that perform support func-
tions.
WASTE HANDLING. The practical and safe dis-
posal of solid waste is the primary objective of a
sanitary landfill. Although the handling of solid
waste at a landfill site resembles an earthmoving
operation, differences exist that require special
consideration. Solid waste is less dense, more com-
pactible, and more heterogeneous than earth.
Spreading a given volume of solid waste requires
less energy than an equal amount of soil.
Because of its size, strength, and shape, solid
waste is not as conducive as soils to compaction
by vibration. In the main, solid waste is compacted
by the compressive forces developed by the overall
massive loading of a landfill machine. If maximum
compaction is desired, a large, heavy machine that
is operated in accordance with the recommendations
contained in Chapter 6 will give better results than
a light machine. Since repeated loading of the solid
waste improves its compaction, enough machines
should be available that 2 to 5 compaction passes
can be made during the operating day. If it is not
possible to purchase a large machine, spreading
the solid waste into thinner layers and making more
passes with a lighter machine may suffice. The
optimum number of passes depends on the moisture
content and composition of the solid waste. Their
exact relationships, as they affect density, have
not, however, been determined.
Machines that operate on solid waste, espe-
cially during spreading and compaction, are sus-
ceptible to overheating because of clogged radiators,
to broken fuel and hydraulic lines, to tire punctures,
and to damage incurred when waste becomes lodged
in the tracks or between the wheels and the ma-
chine body. The various accessories that are avail-
able to help alleviate these problems are discussed
later in this chapter.
COVER MATERIAL HANDLING. The excavating,
hauling, spreading, and compacting of cover material
are similar to other earthmoving operations, such
as highway construction. In landfill operations, how-
ever, rigorous control of moisture content to achieve
maximum soil density is not usually practiced,
although it is desirable to wet a very dry soil some-
what to hold down dust and to improve compaction.
The equipment operator who spreads and compacts
cover material should be capable of grading it as
specified to drain the site. Specific earthmoving
requirements vary according to the topographic and
soil conditions present. Sand, gravel, and certain
loamy clay and loamy silt soils can be excavated
with wheeled equipment, but tougher natural soils
require tracked machines. If the natural soil cover
is thin, underlying formations composed of weath-
ered or partially decomposed bedrock may make
39
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suitable cover material, but they may have to be
broken with a crawler equipped with a rock ripper.
Rippable materials include most uncemented shale,
thinly interbedded limestone and shale, poorly
cemented siltstone, and partially decomposed gran-
itic rock types. These are, however, only generaliza-
tions, and a particular soil may be easier to excavate
or more difficult to work because soil properties
may change significantly from season to season.
Glacial till can usually be excavated by heavy tracked
equipment if the compact clay has a moderate to
high moisture content, as in the spring and early
summer. In the late summer and fall, when less
rain falls, glacial tills or clay soils of similar texture
and composition dehydrate and become very hard
and difficult to excavate. They must often be ripped
first. Freezing weather may also require the use
of a rock ripper to remove the frost layer.
SUPPORT FUNCTIONS. A sanitary landfill re-
quires support equipment to perform such tasks as
road construction and maintenance, dust control, fire
protection, and possibly to provide assistance in
unloading operations. Road construction and main-
tenance must be provided so that the working face
can be reached in all types of weather. This often
requires the adoption of a dust control program
which, in turn, may call for the use of special equip-
ment, such as a water wagon and sprinkler or a salt
spreader. Mobile firefighting equipment may be sta-
tioned on the site or readily available nearby. Assis-
tance in the unloading operation may include
emptying collection trucks equipped with a movable
bulkhead and pulling out vehicles that become stuck
near the operating face during rainy weather. Unless
there are many collection trucks requiring assis-
tance, the spreading and compacting machine can
handle the situation.
Equipment Types and
Characteristics
A knowledge of the types and characteristics
of earthmoving machines is essential if the right
selection is to be made, especially since most
machines can perform multiple functions.
CRAWLER MACHINES. Crawler machines are of
two types: dozer and loader. Other common names
for them are: bulldozer, crawler, crawler dozer, track
loader, front end loader, and bullclam; many trade
names are also used. They all have good flotation
and traction capabilities, because their self-laying
tracks provide large ground contact areas. The
crawler is excellent for excavating work and moving
over unstable surfaces, but it can operate approxi-
mately only 8 mph, forward or reverse.
The crawler dozer is excellent for grading and
Figure 19. The crawler dozer is excellent for
grading and can be economically used for dozing waste
for up to 300 ft. It should be equipped with a U-
shaped blade that has been fitted with a top extension
to increase its pushing area.
can be economically used for dozing waste or earth
over distances of up to 300 ft (Figure 19). It is
usually fitted with a straight dozer blade for earth-
work, but at a sanitary landfill it should be equipped
with a U-shaped blade that has been fitted with a
top extension (trash or landfill blade) to push more
solid waste.
Unlike the crawler dozer, the crawler loader
can lift materials off the ground, but its bucket
is not as wide, and it is not able, therefore, to spread
as much solid waste. The crawler loader is an excel-
lent excavator and can carry soil as much as 300 ft.
There are two types of buckets usually used for
sanitary landfilling: the general purpose and the
multiple purpose (Figures 20-21). The general-pur-
pose bucket is a scoop of one-piece construction.
The multiple-purpose bucket, which is also known
as a bullclam or 4 in 1, is of two-piece construction,
is hinged at the top, and is hydraulically operated.
It can thus clamp onto such objects as tree trunks
or telephone poles and lift and place them in the
fill, or it can crush junked autos or washing ma-
chines. It is also useful in spreading cover material.
The general-purpose and multiple-purpose buckets
come in many sizes. Matching a bucket to a machine
should be done with the advice of the machine
manufacturer. A landfill blade similar to that used
on dozers can also be fitted to loaders.
RUBBER-TIRED MACHINES. Both dozers and
loaders are available with rubber-tired wheels. They
are generally faster than crawler machines (maximum
forward or reverse speed of about 29 mph) but do
not excavate as well. The plausible claim has been
made that because the weight of rubber-tired ma-
chines is transferred to the ground over a much
smaller contact area, they provide better compac-
tion, but significant differences of in-place density
40
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Figure 20. Crawler loader with a general-purpose
bucket of one-piece construction. The crawler loader
is an excellent excavator.
Figure 21. Crawler loader with a multiple-
purpose bucket, which is also known as a bullclam or
4 in 1. The bucket can clamp onto such objects as tree
trunks and telephone poles and lift and place them in
the fill; it can also crush junked cars and washing
machines.
Figure 22. The rubber-tired dozer is used only
infrequently at sanitary landfills. Because of the rough
and spongy surface formed by compacted solid waste,
this machine does not grade as well as a crawler
dozer.
Figure 23. The rubber-tired loader is usually
equipped with a general-purpose or multiple-purpose
bucket. Because of its high operating speed, this ma-
chine is especially suited for putting cover material
into haul trucks or carrying it economically for dis-
tances of up to 600 ft.
have not been proven. Because their loads are con-
centrated more, rubber-tired machines have less
flotation and traction than crawler machines. Their
higher speed, however, allows them to complete
more cycles or passes in the same amount of time
than a crawler machine. Rubber-tired machines per-
form satisfactorily on landfill sites if they are
equipped with steel guarded tires, called rock tires
or landfill tires. Rubber-tired machines can be eco-
nomically operated at distances of up to 600 ft.
The rubber-tired dozer is not commonly used
at a sanitary landfill. Because of the rough and
spongy surface formed by compacted solid waste
and the concentrated wheel loads, the rubber-tired
dozer does not grade as well as a crawler dozer.
The flotation of the crawler dozer makes it much
more suitable for grading operations. The rubber-
tired dozer should be equipped with a landfill or
trash blade (Figure 22) similar to that recommended
for a track dozer.
The rubber-tired loader is usually equipped
with a general-purpose or multiple-purpose bucket
(Figure 23). A particular asset of this machine is
the high speed and mobility of its operation. When
it is only needed part time at a sanitary landfill,
it can be driven over public roads to perform other
jobs. Because of its high operating speed, the
rubber-tired loader is especially suited for putting
cover material into haul trucks or carrying it eco-
nomically over distances of up to 600 ft.
LANDFILL COMPACTORS. Several equipment
manufacturers are marketing landfill compactors
41
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equipped with large trash blades. In general, these
machines are modifications of road compactors and
log skidders. Rubber-tired dozers and loaders have
also been modified. The power train and structure of
landfill compactors are similar to those of rubber-
tired machines, and their major asset is their steel
wheels (Figure 24). The wheels are either rubber
tires sheathed in steel or hollow steel cores; both
types are studded with load concentrators (Figure
25).
Steel-wheeled machines probably impart great-
er crushing and compactive effort than do rubber-
tired or crawler machines. A study comparing a
47,000-lb steel-wheeled compactor, the same unit
equipped with rubber tires, and a 62,000-lb crawler
dozer indicated that under the same set of con-
ditions, the in-place dry density of solid waste
compacted by the steel-wheeled compactor was 13
percent greater than that effected by the crawler
dozer and the rubber-tired compactor.1
The landfill compactor is an excellent machine
for spreading and compacting on flat or level sur-
faces and operates fairly well on moderate slopes,
but it lacks traction when operating on steep slopes
or when excavating. Its maximum achievable speed
while spreading and compacting on a level surface
is about 23 mph, forward and reverse. This makes
it faster than a crawler but slower than a rubber-
tired machine. Since landfill compactors operate
at high speeds and produce good in-place densities,
they are best applied when they are used only for
spreading and compacting solid waste and cover
material. When the cover material is a clay, it and
some of the solid waste lodge between the load
concentrators and must be continually removed by
cleaner bars. The surface of a soil layer compacted
with a landfill compactor is usually covered by pits
or indentations formed by the load concentrators.
Numerous passes are needed to minimize the rough-
ness of the surface.
SCRAPERS. Scrapers are available as self-pro-
pelled and towed models having a wide range of
capacities (Figure 26). This type of earthmoving
machine can haul cover material economically over
relatively long distances (more than 1,000 ft for
the self-propelled versions and 300 to 1,000 ft for
towed models). Their prime function is to excavate,
haul, and spread cover material. Since they are
heavy when loaded, routing them over the fill area
will help compact the solid waste. Hauling capacities
range from 2 to 40 cu yd.
DRAGLINE. Large excavations can be made eco-
nomically with a dragline. Its outstanding character-
istic is its ability to dig up moderately hard soils
and cast or throw them away from the excavation.
Because of this feature, it can also be used to
Figure 24. In general, landfill compactors are
modifications of road compactors and log skidders.
The power train and structure are similar to those of
rubber-tired machines. The major asset of the landfill
compactor is its steel wheels; it can probably achieve
better compaction than a rubber-tired or crawler
machine.
spread cover material over compacted solid waste.
It is particularly useful in wetland operations. The
dragline is most commonly found at large landfills
where the trench method is used or where cover
material is obtained from a borrow pit. As a rule
42
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/\ /\
Tamping
Cleat
Geometric
Triangular
Figure 25. The wheels of a landfill compactor
are either rubber tires sheathed in steel or hollow
steel cores; both types are studded with load concen-
trators.
of thumb, the boom length should be two times
the trench width. Buckets used at landfills usually
range from 1 to 3 cu yd.
SPECIAL-PURPOSE EQUIPMENT. Several pieces
of earthmoving and road construction equipment are
put to limited use on landfills that dispose of less
than 1,000 tons a day. Their purchase may not,
therefore, be warranted. When they are needed,
they can be borrowed, leased, rented, or the work
can be performed under contract.
The road grader can be used to maintain dirt
and gravel roads on the site, to grade the inter-
mediate and final cover, and to maintain drainage
channels surrounding the fill.
Water is useful in controlling blowing litter
at the working face and control of dust from on-site
roads. Water wagons range from converted tank
trucks to highly specialized, heavy vehicles that are
generally used in road construction operations.
They can also be used at the landfill to fight fires.
The road sweeper is a real asset at sites where
mud is tracked onto the public road system. Its
periodic use will encourage local residents to accept
the landfill because roadways remain safe.
ACCESSORIES. The equipment used at landfills
can be provided with accessories that protect the
machine and operator and increase the effectiveness
and versatility of the machine (Table 8).
Engine screens and radiator guards keep paper
and wire from clogging radiator pores and causing
the engine to overheat. A reversible fan can also
help alleviate this problem, because the direction
of air flow or vane pitch can be changed in less
than 5 min. Under-chassis guards can be installed
to shield the engine, and hydraulic lines and other
essential items of the machine should also be
protected if they are susceptible to damage (Fig-
ure 27).
The operator's comfort, safety, and efficiency
can be increased by providing roll bars, a canopy
or cab, cab or helmet air conditioning, and backup
warning systems. A canopy is especially desirable
for machines that operate in a trench into which
Figure 26. Scrapers are available as self-
propelled or towed models; their prime function is to
excavate, haul, and spread cover material. Capacities
range from 2 to 40 cu yd.
waste is dumped from above. Cabs are particularly
useful when the working area is very dusty or the
operator must work in very cold weather. Because
rubber-tired machines and landfill compactors oper-
ate at relatively high speeds, an audible backup
warning system should be provided to alert other
equipment operators and personnel in the imme-
diate area. This system is also desirable on crawler
43
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TABLE 8
Recommended and Optional Accessories
for Landfill Equipment
Dozers
Accessory Crawler Rubber-
Tired
Dozer blade
U-blade
Landfill blade
Hydraulic controls
Rippers
Engine screens
Radiator guards-hinged
Cab or helmet
air conditioning
Ballast weights
Multiple-purpose
bucket
General-purpose
bucket
Reversible fan
Steel-guarded tires
Life-arm extensions
Cleaner bars
Roll bars
Backing warning system
0*
0
Rt
R
0
R
R
0
0
—
—
R
—
—
—
R
R
0
0
R
R
—
R
R
0
0
—
—
R
R
—
—
R
R
Loaders
Crawler
—
—
0
R
0
R
R
0
R
R
0
R
—
0
—
R
R
Landfill
Rubber- corn-
Tired pactor
—
—
0
R
—
R
R
0
R
R
0
R
R
0
—
R
R
0
0
R
R
—
R
R
0
R
—
—
R
—
—
R
R
R
* O, Optional.
f R, Recommended
machines, especially when two or more are operat-
ing in the same area.
Equipment versatility and effectiveness can
be increased by use of a number of accessories.
A hydraulically operated ripper is needed when
extensive excavation must be carried out in hard
soils. It should be mounted on a tracked machine
to take advantage of its greater traction. (Back-
rippers, hinged teeth attached to buckets or blades
that dig into the soil when the machine is reversing,
are not as effective as hydraulically operaed rip-
SEVERSIBLE FAI
(curmr VIEW)
UNDER CHASSIS
MACHINE GUARD
Figure 27. The equipment used at sanitary land-
fills can be provided with accessories that protect the
machine and operator and increase their effectiveness.
pers.) To give rubber-tired machines and landfill
compactors more traction, their wheels can be
ballasted with a calcium chloride solution or water,
and steel or concrete counterweights can be used
on loaders and landfill compactors.
Different power trains can be used on many
large machines. The power shift and torque conver-
ter options are preferable to the dry clutch, direct-
drive models because greater speed of operation
and less strain on the engine and operator are
possible with them.
COMPARISON OF CHARACTERISTICS. The abil-
ity of various machines to perform the many functions
that must be carried out at a sanitary landfill should
be analyzed with respect to the needs and conditions
of each site (Table 9). General recommendations
regarding the best types and sizes of machines to
use at a specific landfill can be misleading. More
exhaustive analysis is needed before the final equip-
ment selection is made.
Size of Operation
Definition of functions and evaluation of equip-
ment performance must be matched with the size
of the landfill to determine the type, number, and
size of the machines needed. No one machine is
capable of performing all functions equally well.
Neither can it be assumed that equipment effec-
tively used at one site will be the most suitable
elsewhere. Unfortunately, production rates expressed
in tons of solid waste spread and compacted per
hour are not readily available for comparison.
Guides that have been proposed by equipment man-
ufacturers and others should be considered only
rough estimates of equipment needs fora particular
landfill (Table 10).
SINGLE-MACHINE SITES. Particular difficulty
is encountered when selecting equipment for a site
44
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TABLE 9
Performance Characteristics of Landfill Equipment*!
Solid Waste
Equipment
Crawler dozer
Carwler loader
Rubber-tired dozer
Rubber-tired loader
Landfill compactor
Scraper
Dragline
Spreading
E
G
E
G
E
NA
NA
Compacting
G
G
G
G
E
NA
NA
Excavating
E
E
F
F
P
G
E
Cover
Spreading
E
G
G
G
G
E
F
Material
Compacting
G
G
G
G
E
NA
NA
Hauling
NA
NA
NA
NA
NA
E
NA
* Basis of evaluation: Easily workable soil and cover material haul distance greater than 1,000 ft.
t Rating Key: E, excellent; G, good; F, fair; P, poor; NA, not applicable
TABLE 10
Landfill Equipment Needs3
Solid
waste handled
(tons/8 hr)
0-20
20-50
50-130
130-250
250-500
500-plus
Crawler loader
Flywheel
horsepower
<70
70
to
100
100
to
130
150
to
190
Weight*
(Ib)
< 20,000
20,000
to
25,000
25,000
to
32,500
32,500
to
45,000
combination of
machines
COMB
Crawler
Flywheel
horsepower
<80
80
to
110
110
to
130
150
to
180
250
to
280
(NATION
dozer
Weight*
(Ib)
< 15,000
15,000
to
20,000
20,000
to
25,000
30,000
to
35,000
47,500
to
52,000
0 F M A C
Rubber-tired loader
Flywheel Weight*
horsepower (Ib)
<100
100
to
120
120
to
150
150
to
190
MINES
< 20,000
20,000
to
22,500
22,500
to
27,500
27,500
to
35,000
combination of
machines
Note: Compiled from assorted promotional material from equipment manufacturers and based on ability of one machine
in stated class to spread, compact, .and cover within 300 ft of working face
" Basic weight without bucket, blade, or other accessories
where only one machine will be used. It must be
capable of spreading and compacting both solid
waste and cover material, but it may also have to
be used to excavate trenches or cover material.
In general, the most versatile machine for a small
landfill is the tracked or rubber-tired loader. If the
machine will not be used full time, a wheeled loader
is preferable because of its mobility. If the machine
is to stay at the site full time and will not be
required to load cover material into trucks, a crawl-
er dozer may be better.
Regardless of the size of a single-machine
operation, the dependability of the machine should
be high. Arrangements should be made in advance
to obtain a replacement if a breakdown occurs,
because this development is no excuse for unaccept-
able disposal. A replacement machine may be made
available through the equipment dealer, a local
45
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TABLE 11
Machine Capital Cost
Equipped Machine
Flywheel
Machine type Horsepower
Crawler dozer
Crawler loader
Rubber-tired loader
<80
110-130
250-280
<70
100-130
100-130
150-190
150-190
<100
<100
120-150
120-150
Weight
(Ib)
< 15,000
20,000-25,000
47,500-52,000
< 20,000
25,000-32,500
25,000-32,500
32,500-45,000
32,500-45,000
< 20,000
< 20,000
22,500-27,500
22,500-27,500
Approximate
weight*
(Ib)
19,000
32,000
67,000
23,000
31,000
32,000
45,000
47,000
17,000
18,000
23,000
26,000
Approximate
costf
($)
21,000
38,000
70,000
21,000
30,000
32,000
46,000
49,000
21,000
23,000
33,000
36,000
Comment
landfill blade
landfill blade
landfill blade
GPBJ— 1 cu yd
GPB —2 cu yd
MPB**-13/4 cu yij
GPB— 3 cu yd
MPB-21/2 cu yd
GPB— 1% cu yd
MPB-iy2cuyd
GPB— 4 cu yd
MPB-2V4 cu yd
* Basic machine plus engine sidescreens, radia
bucket, or multiple-purpose bucket as noted.
tJune 1970.
t General-purpose bucket.
** Multiple-purpose bucket
id either a landfill blade, general-purpose
contractor, or a municipal public works department.
SMALL SITES. Municipalities disposing of less
than 10 tons a day may find the cost of owning a
small dozer or loader too high. If excavation and
stockpiling of cover material are done on contract,
a farm tractor equipped with a blade or bucket may
be sufficient for spreading the solid waste. The
tractor will not, however, be able to produce much
compaction, even if the waste is spread in thin
layers. The poor compaction achieved means that
a larger fill area will be needed. This requirement,
together with the total cost of the contract work,
should be compared to the expense of owning and
operating a small dozer or loader.
MULTIPLE-MACHINE OPERATION. It is easier
to select equipment for a multiple-machine operation
than it is for a one-machine operation. Such special-
ized machines as scrapers and landfill compactors
may then be economical to use. If cover material
has been stockpiled and more than one machine is
available, operations need not be interrupted when
an equipment breakdown occurs. As an added pre-
caution, replacement machines should be available
through a lease, contract, or borrowing arrangement.
Costs
The equipment selected for a sanitary landfill
must not only be able to perform well under con-
ditions present at the site, it must also do so at
the least total cost. Equipment costs, both capital
and operating, represent a significant portion of
the expenses incurred in operating a sanitary land-
fill.
CAPITAL COSTS. Except for land, the cost of
equipment may be the greatest portion of initial ex-
penditures. The sanitary landfill equipment market is
very competitive, but rough approximations of costs
have been developed (Table 11). A crawler machine
weighing 29,000 Ib without accessories costs about
$29,000. With engine sidescreens, radiator guards,
reversible fan, roll bar, and a multiple-purpose
bucket, the same machine costs approximately
$32,000. A new dragline can cost between $75,000
and $110,000 depending on the length of its boom
and cables, and the size of its bucket. In general,
most landfill equipment used for excavating, spread-
ing, and compacting has a useful life of 5 years or
10,000 operating hours.
The price of a used machine depends on its
type, size, condition, and number of recorded oper-
ating hours. Specific resale values are available
from auctioneers and manufacturers of earthmov-
ing equipment. The condition and remaining useful
life of used equipment should be determined by
an expert.
OPERATING AND MAINTENANCE COSTS. Pur
chases of fuel, oil, tires, lubricants, and filters and
46
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any expenses associated with routine maintenance
are considered operating costs. Expenditures on fuel
account for approximately 90 percent of operating
costs. The expense of operating dozers, loaders,
and landfill compactors varies according to type and
make; the manufacturer should, therefore, be con-
sulted for specific estimates. Generally speaking,
direct operating costs are $3.00 per hour. The skill
of the equipment operator, the type of waste
handled, topography, and soil conditions also affect
operating costs.
Maintenance costs, parts, and labor also vary
widely but can be approximated by spreading one-
half the initial cost of the machine over its antici-
pated useful life (10,000 hr). To make these costs
more predictable, most equipment dealers offer
lease agreements and maintenance contracts. Long
downtimes usually associated with major repairs
can be reduced by taking advantage of programs
offered by most equipment dealers.
High operating costs are frequently associated
with low initial costs of the equipment and vice
versa. The purchaser should, therefore, require that
equipment bids include estimated operating costs.
Actual operating and maintenance expenses
should be determined during site operation by use
of a cost accounting system.2 This information can
be used to identify areas where costs may be re-
duced; excessive fuel consumption, for example,
may mean the machine needs adjustment or that
operating procedures should be modified. Data
from the cost accounting system can be used to
more accurately predict operating and maintenance
costs.
REFERENCES
1. STONE, R., and E. T. CONRAD. Landfill compaction equipment efficiency.
Public Works, 100(5):111-113, May 1969.
2. ZAUSNER, E. R. An accounting system for sanitary landfill operations.
Public Health Service Publication No. 2007. Washington, U.S. Gov-
ernment Printing Office, 1969. 18 p.
47
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CHAPTER 8
completed sanitary landfill
Reclaiming land by filling and raising the
ground surface is one of the greatest benefits of
sanitary landfilling. The completed sanitary landfill
can be used for many purposes, but all of them
must be planned before operations begin.
Characteristics
The designer should know the purposed use
of the completed sanitary landfill before he begins
to work. Unlike an earthfill, a sanitary landfill con-
sists of cells containing a great variety of materials
having different physical, chemical, and biological
properties. The decomposing solid waste imparts
characteristics to the fill that are peculiar to sani-
tary landfills. These characteristics require that the
designer plan for gas and water controls, cell con-
figuration, cover material specifications (as deter-
mined by the planned use), and the periodic main-
tenance needed at the completed sanitary landfill.
DECOMPOSITION. Most of the materials in a
sanitary landfill will decompose, but at varying rates.
Food wastes decompose readily, are moderately
compactible, and form organic acids that aid de-
composition. Garden wastes are resilient and diffi-
cult to compact but generally decompose rapidly.
Paper products and wood decay at a slower rate
than food wastes. Paper is easily compacted and
may be pushed into voids, whereas lumber, tree
branches, and stumps are difficult to compact and
hinder the compaction of adjacent wastes. Car
bodies, metal containers, and household appliances
can be compacted and will slowly rust in the fill
with the help of organic acids produced by decom-
posing food wastes. Glass and ceramics are usually
easily compacted but do not degrade in a landfill.
Plastics and rubber are resilient and difficult to
compact; rubber decomposes very slowly, most plas-
tics not at all. Leather and textiles are slightly
resilient but can be compacted; they decompose,
but at a much slower rate than garden and food
wastes. Rocks, dirt, ashes, and construction rubble
do not decompose and can be easily worked and
compacted.
DENSITY. The density of solid waste in a landfill
is quite variable. One that is well constructed can
have an in-place density as great as 1,500 Ib per
cu yd, while that of poorly compacted solid waste
may be only 500. Generally, 800 to 1,000 Ib per
cu yd can be achieved with a moderate compactive
effort. Soft and hard spots occur within the fill as
a result of different decomposition rates and com-
paction densities. Density influences such other
characteristics as settlement and bearing capacity.
SETTLEMENT. A sanitary landfill will settle as a
result of waste decomposition, filtering of fines,
superimposed loads, and its own weight. Bridging
that occurs during construction produces voids.
As the waste decomposes, fine particles from the
cover material and overlying solid waste often sift
into these voids. The weight of the overhead waste
and cover material helps consolidate the fill, and
this development is furthered when more cover
material is added or a structure or roadway is con-
structed on the fill.
The most significant cause of settlement is
waste decomposition, which is greatly influenced
by the amount of water in the fill. A landfill will
settle more slowly if only limited water is available
to decompose the waste chemically and biologically.
In Seattle, where rainfall exceeds 30 in. per year,
a 20-ft fill settled 4 ft in the first year after it was
completed.1 In Los Angeles, where less than 15 in.
of rain falls per year, 3 years after a landfill had
48
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been completed a 75-ft high area had settled only
2.3 ft, and another section that had been 46 ft
high had settled a mere 1.3 ft.2
Settlement also depends on the types of wastes
disposed of, the volume of cover material used with
respect to the volume of wastes disposed of, and
the compaction achieved during construction. A fill
composed only of construction and demolition debris
will not settle as much as one that is constructed
of residential solid wastes. A landfill constructed
of highly compacted waste will settle less than one
that is poorly compacted. If two landfills contain
the same types of wastes and are constructed to
the same height, but one has a waste-to-cover vol-
ume ratio of 1:1 and the other a ratio of 4:1, the
first will settle less. Because of the many factors
involved, a fill may settle as much as 33 percent.3
Settling can produce wide cracks in the cover
material that expose the wastes to rats and flies,
allow water to infiltrate, and permit gas to escape.
Differential settling may form depressions that per-
mit water to pond and infiltrate the fill. Settling
may also cause structures on the landfill to sag
and possibly collapse; the underground utility lines
that serve these buildings or traverse the site may
then shear. Because every landfill settles, its sur-
face should be periodically inspected and soil
should be added and graded when necessary.
BEARING CAPACITY. The bearing capacity of a
completed sanitary landfill is the measure of its
ability in pounds per square foot to support founda-
tions and keep them intact. Very little information
is available on the subject, but a few investigators
place the bearing capacity of a completed landfill
between 500 and 800 Ib per sq ft4; higher values
have, however, been noted.5 Since there is no defi-
nite procedure for interpreting the results of solid
waste bearing tests, any value obtained should be
viewed with extreme caution. Almost without excep-
tion, the integrity and bearing capacity of soil cover
depend on the underlying solid waste. Most bearing
strength tests of soil are conducted over a short
period—several minutes for granular materials to
a maximum of 3 days for clay having a high mois-
ture or air content. During the test, the soil adjusts
to its limits under the load imposed and conditions
of confinement. Solid waste, on the other hand does
not follow this pattern of deformation but continues
to alter its structure and composition over a long
period of time. Natural soils, which are not as
heterogeneous as solid waste, produce test values
that fall within a predictable range. Moreover, re-
peated tests of the soil will produce similar results
—similar relationships have not been established
for solid waste.
LANDFILL GASES. Landfill gases continue to be
produced after the landfill is completed and can
accumulate in structures or soil, cause explosions,
and stunt or kill vegetation.6 Placement of a thick,
moist, vegetative, final cover may act as a gas-tight
lid that forces gases to migrate laterally from the
landfill. If the site is converted into a paved parking
lot, this may also prevent the gases from venting
into the atmosphere. Design of gas controls should,
therefore, conform with the planned use of the
completed fill.
CORROSION. The decomposing material in a
landfill is very corrosive. Organic acids are produced
from food, garden, and paper wastes, and some
weak acids are derived from ashes. Unprotected
steel and galvanized pipe used for utility lines,
leachate drains, and building foundations are sub-
ject to severe and rapid pitting. All structural ma-
terials susceptible to corrosion should be protected.
Acids present in a saintary landfill can deteriorate
a concrete surface and thus expose the reinforcing
steel; this could eventually cause the concrete to
fail.
Uses
There are many ways in which a completed
sanitary landfill can be used; it can, for example,
be converted into a green area or be designed for
recreational, agricultural, or light construction pur-
poses. The landfill designer should evaluate each
proposal from a technical and economic viewpoint.
More suitable land is often available elsewhere that
would not require the expensive construction tech-
niques required at a sanitary landfill.
GREEN AREA. The use of a completed sanitary
landfill as a green area is very common. No expen-
sive structures are built, and a grassed area is
established for the pleasure of the community.
Some maintenance work is, however, required to
keep the fill surface from being eroded by wind
and water. The cover material should be graded to
prevent water from ponding and infiltrating the fill.
Gas and water monitoring stations, installed during
construction, should be periodically sampled until
the landfill stabilizes. Gas and water controls and
drains also require periodic inspection and main-
tenance.
If the final cover material is thin, only shallow-
rooted grass, flowers, and shrubs should be planted
on the landfill surface. The decomposing solid waste
may be toxic to plants whose roots penetrate through
the bottom of the final cover. An accumulation of
landfill gas in the root zone may interfere with the
normal metabolism of plants. This can be avoided
by selecting a cover material having a low water-
holding capacity, but this type of soil provides poor
49
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support for vegetation. On the other hand, a moist
soil does not allow decomposition gas to disperse
and consequently gas venting must be considered.
The most commonly used vegetation is grass.
Most pasture and hay grasses are shallow-rooted
and can be used on a landfill having only 2 ft of
final cover, but alfalfa and clover need more than
this. The soil used for final cover influences the
choice of vegetation. Some grasses, such as tall
meadow oat grass, thrive well on light sand or
gravelly soils, while others, such as timothy grass,
do better in such heavier soils as clays and loams.
Climate also influences the selection of
grasses. Bermuda is a good soil binder and thrives
in southern States. Perennial rye does best where
the climate is cool and moist and winter is mild; it
roots rapidly but dies off in 2 to 3 years if
shaded. Redtop and bent grass thrive almost any-
where except in drier areas and the extreme south.
The selection of the grass or mixture of grasses
depends, therefore, on climate, depth of the root
system, and soil used for cover material.* Mowing
and irrigating requirements should also be con-
sidered. In general, it is not advisable to irrigate the
landfill surface, because the water may infiltrate and
leach the fill.
AGRJCULTURE. A completed sanitary landfill
can be made productive by turning it into pasture or
crop land. Many of the grasses mentioned above
are suitable for hay production. Corn and wheat
usually have 4-ft roots, but the latter occasionally
has longer ones. The depth of the final cover must,
therefore, be increased accordingly.
If cultivated crops are used, the final cover
should be thick enough that roots or cultivating do
not disturb its bottom foot. If the landfill is to be
cultivated, a 1- to 2-ft layer of relatively impermea-
ble soil, such as clay, may be placed on top of the
solid waste and an additional layer of agricultural
soil placed above to prevent the clay from drying
out. Excessive moisture will also be prevented from
entering the fill. Such a scheme of final cover place-
ment must also provide for gas venting via gravel
trenches or pipes.
CONSTRUCTION. A foundations engineering ex-
pert should be consulted if plans call for structures
to be built on or near a completed sanitary landfill.
This is necessary because of the many unique
factors involved—gas movement, corrosion, bearing
capacity, and settlement. The cost of designing, con-
structing, and maintaining buildings is considerably
higher than it is for those erected on a well-
compacted earth fill or on undisturbed soil. The
* Information on the grasses mainly used in a landfill area
is available from county agricultural agents and the
U.S. Soil Conservation Service.
most problem-free technique is to preplan the use
of islands to avoid settlement, corrosion, and bear-
ing-capacity problems. Ideally, the islands should be
undisturbed soils that are bypassed during excavat-
ing and landfilling operations. Settlement would
then be governed by the normal properties of the
undisturbed soil. Alternatively, truck loads of rocks,
dirt, and rubble could be laid down and compacted
during construction of the landfill at places where
the proposed structure would be built.
The decomposing landfilled waste can be ex-
cavated and replaced with compacted rock or soil fill,
but this method is very expensive and could prove
hazardous to the construction workers. The decom-
posing waste emits a very putrid smell, and hydrogen
sulfide, a toxic gas, may be present with methane,
an explosive gas. These two gases should be
monitored throughout the excavating operation. Gas
masks may have to be provided for the workmen,
and no open flames should be permitted.
Piles can also be used to support buildings
when the piles are driven completely through the
refuse to firm soil or rock. Some of the piles should
be battered (angled) to resist lateral movement that
may occur in the fill. Another factor to consider is
the load imposed on the piles by solid wastes set-
tling around them. The standard field penetration
resistance test is used to determine the strength of
the earth material in which the piles are to be
founded. During this test, penetration will be re-
sisted by the solid waste, but as the refuse decom-
poses and settling occurs, it may no longer resist
and will more likely create a downward force on the
pile. There are no data for established procedures
for predicting this change in force.
Several peculiar problems arise when piles
are used to support a structure over a landfill. The
decomposing waste is very corrosive, so the piles
must be protected with corrosion-resistant coatings.
It may be very difficult to drive the piles through the
waste if large bulky items, such as junked cars and
broken concrete, are in the fill where the structure
is to be located. The fill underlying a pile-supported
structure may settle, and voids or air spaces may
develop between the landfill surface and the bottom
of the structure. Landfill gases could accumulate
in these voids and create an explosion hazard.
Light, one-story buildings are sometimes con-
structed on the landfill surface. The bearing capac-
ity of the landfill should be determined by field
investigations in order to design continuous founda-
tions. Foundations should be reinforced to bridge
any gaps that may occur because of differential
settling in the fill. Continuous floor slabs reinforced
as mats can be used, and the structure should be
designed to accommodate settlement. Doors, win-
50
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dows, and partitions should be able to adapt to
slight differential movement between them and the
structural framing. Roads, parking lots, sidewalks,
and other paved areas should be constructed of a
flexible and easily repairable material, such as
gravel or asphaltic concrete.
Consolidating the landfill to improve its bear-
ing capacity and reduce settlement by surcharging
it with a heavy layer of soil does not directly in-
fluence the decomposition rate. If the surcharge
load is removed and the structure is built before
the waste has stabilized, settlement will still be a
problem, and the bearing capacity may not be as
great as expected.
None of the methods for supporting a struc-
ture over a landfill are problem-free. A common dif-
ficulty is keeping landfill gases from accumulating in
the structure. Even buildings erected on undis-
turbed islands of soil must be specially designed to
prevent this from developing. A layer of sand can
be laid over the proposed structural area and then
be covered by two or more layers of polyvinyl chlo-
ride sheeting. An additional layer of sand can then
be emplaced. If the bottom layer of sand is not
saturated, it will act as a gas-permeable vent, and
the sheeting will prevent the gas from entering or
collecting under the structure. The top layer of
sand protects the sheeting from being punctured.
Another approach is to place an impermeable mem-
brane of jute and asphalt under all below-grade
portions of the structure. A gravel or sand layer must
underlie the jute-asphalt membrane and be vented
to the atmosphere. The most reliable method is to
construct a ventilated false basement to keep gas
from accumulating.
Utility connections must be made gas proof if
they enter a structure below grade. If the building is
surrounded by filled land, utility lines that traverse
the fill must be flexible, and slack should be pro-
vided so the lines can adjust to settlement. Flexible
plastic conduits are more expensive than other
materials but would probably work best, because
they are elastic and resist corrosion. Gravity waste-
water pipelines may develop low points if the fill
settles. Liquid wastes should be pumped to the
nearest sewer unless the grade from the structure
to the sewer prevents low points from forming.
Shearing of improperly designed water and waste-
water services caused by differential settlement can
occur where they enter the structure or along the
pipeline that traverses the fill.
RECREATION. Completed landfills are often
used as ski slopes, toboggan runs, coasting hills, ball
fields, golf courses, amphitheaters, playgrounds,
and parks. Small, light buildings, such as conces-
sion stands, sanitary facilities, and equipment
storage sheds, are usually required at recreational
areas. These should also be constructed to keep
settlement and gas problems at a minimum. Other
problems encountered are ponding, cracking, and
erosion of cover material. Periodic maintenance in-
cludes regrading, reseeding, and replenishing the
cover material.
Registration
The completed landfill should be inspected by
the governmental agency responsible for ensuring
its proper operation. Following final acceptance of
the site, a detailed description, including a plat,
should be recorded with the proper authority in the
county where the site is located. This provides
future owners or users with adequate information
regarding the previous use of the site. The descrip-
tion should, therefore, include type and general
location of wastes, number and type of lifts, and
details about the original terrain.
REFERENCES
1. DUNN, W. L. Settlement and temperature of a covered refuse dump. Trend
in Engineering (University of Washington), 9(1):19-21, Jan. 1957.
2. County of Los Angeles, Department of County Engineer and Engineering-
Science, Inc. Development of construction and use criteria for sani-
tary landfills; an interim report. Cincinnati, U.S. Department of
Health, Education, and Welfare, 1969. [267 p.]
3. Refuse volume reduction in a sanitary landfill. Journal of the Sanitary Engi-
neering Division, Proc. ASCE, 85(SA6):37-50, Nov. 1959.
4. SOWERS, G. F. Foundation problems in sanitary landfills. Journal of the
Sanitary Engineering Division, Proc. ASCE, 94(SA1):103-116, Feb.
1968.
5. ELIASSEN, R. Load-bearing characteristics of landfills. Engineering News-
Record, 129(11):103-105, Sept. 10, 1942.
6. How to use your completed landfills. American City, 83(8):91-94, Aug. 1965.
51
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CHART
management
The size and scale of operations carried out at
a sanitary landfill and the area served will influence
the mechanics of management. The purpose and
goal of solid waste managers should be to con-
solidate and coordinate all the resources necessary
to dispose of solid wastes in the most sanitary
and efficient manner possible.
Administrative Agency
The responsibility for operating a sanitary land-
fill is normally determined by the community ad-
ministrative structure involved, and it must do so
in the light of its own circumstances.
MUNICIPAL OPERATIONS. In most municipal
operations, administrative responsibility is assigned
to the department of public works, one of whose
divisions manages the solid waste program. As the
scope of this division's activities increases, it is
desirable to subdivide the division into functional
sections. Regradless of organizational structure,
collection and disposal plans and operations must
be coordinated to achieve satisfactory and economi-
cal solid waste management.
SPECIAL DISTRICTS. Many States have enabl-
ing legislation that permits the formation of special-
purpose districts, which can include solid waste
disposal districts. These districts are advantageous
in that they can serve many political jurisdictions
and may have provisions for levying special taxes.
Before any special district is considered, the State
laws applicable to them should be investigated.
COUNTY OPERATIONS. A sanitary landfill ad-
ministered by a county may have advantages over a
municipal operation. A county operation could serve
a number of incorporated and unincorporated areas
using existing governmental apparatus, and it
might allow comprehensive planning for a larger
geographic area. Other advantages are economy of
scale and greater availability of land.
PRIVATE OPERATIONS. Many sanitary landfills
are operated successfully by private industry under a
contract, franchise, or permit arrangement. In con-
tract operations, the municipality contracts with
the operator to dispose of its solid waste for a fixed
charge per ton or load. The municipality usually
guarantees that the contractor will receive a certain
minimum amount of money. Franchises usually grant
the operator permission to dispose of wastes from
specified areas and charge regulated fees. Permits
allow the operator to accept wastes for disposal
without regard to source.
Private operations may be beneficial to munic-
ipalities that have limited funds, but the community
must not shirk its responsibility for proper solid
waste disposal. Of the three methods, contract op-
erations generally give the municipality the best
guarantee that solid wastes will be disposed of
properly because standards can be written into the
contract.1 Franchises usually provide the next best
control of operation.
Administrative Functions
An administrative agency is responsible for
proper solid waste disposal, including planning,
designing, financing, cost accounting, operating,
recruiting and training, informing the public, and
establishing minimum disposal standards.
FINANCES. Sanitary landfill capital costs in-
clude land, equipment, and site improvements. Op-
erating costs include salaries, utilities, fuel, and
equipment maintenance. Equipment and mainte-
nance costs were discussed in Chapter 7.
52
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There are several sources of funds to meet
capital and operating costs.* The general fund,
derived from taxes, normally cannot provide enough
money to meet capital costs but is often used to
pay for operating expenses. There are advantages
to using the general fund for this purpose. The ad-
ministrative procedures and extra cost of billing and
collecting are eliminated. Since all the taxpayers
help pay for the sanitary landfill, they are more
likely to use the sanitary landfill rather than an open
dump.
Using general funds for landfill operations
does, however, have disadvantages. Cost account-
ing and other administrative procedures may be so
relaxed disposal costs are difficult or impossible to
determine, and users may have to be monitored. It
may also be extremely difficult for solid waste man-
agement operations to get money from the general
fund because of the low priority often assigned to
them.
General obligation borrowing is a common
method of financing the capital costs of a sanitary
landfill. This type of bond generally carries a low
interest rate but is easily marketed because it is
secured by the pledge of real estate taxes and be-
cause all of the real estate within the taxing dis-
trict serves as security for the borrowed funds.
State statutes usually limit the amount of debt a
community can incur. If the debt is already sub-
stantial, this method may not be available. In some
cases, general obligation bonds are retired with
revenues generated by the landfill operation; this
minimizes the ad valorem taxes necessary for bond
retirement.
Revenue bonds differ from general obligation
bonds in that they are secured only by the ability
of the project to earn enough to pay the interest
and retire the bonds. In this case, fees must be
charged to landfill users in amounts necessary to
cover all capital and operating expenses. It is neces-
sary to set the fees high enough to accumulate a
surplus over and above debt service needs in order
to make the bonds attractive to prospective pur-
chasers. This method of financing requires that the
administering agency follow good cost accounting
procedures, and it allows the agency to be the sole
beneficiary of cost saving procedures. In addition,
the producer of solid waste is forced to pay the true
cost of its disposal.
User fees are primarily a source of operating
revenue, but a municipality might also employ them
Additional information is available from Solid Waste Man-
agement Financing, one of a series of guides developed
by the National Association of Counties Research Foun-
dation
to generate funds for future capital expenditures.
The fees can be adjusted to cover not only the op-
erating and capital costs of present landfills but
also to provide a surplus for acquiring land and
equipment. Fees do not provide the capital outlay
needed to start a sanitary landfill.
Although fees necessitate more work and ex-
pense because of the weighing, billing, and collect-
ing involved, these requirements provide an insight
into the management and operation of the landfill.
Commercial haulers are usually billed on a per ton
basis. Since the individual loads from homes are
small, the users are charged on a per load basis
to reduce weighing and bookkeeping. Because fee
operations require that collection vehicles be re-
corded at the gate, this provides an additional con-
trol over wastes received at the landfill.
OPERATIONAL COST CONTROL. A primary duty
of administration is to monitor and control the cost
of operation. Cost accounting isolates the detailed
expenses of ownership and operation and permits
comparison of costs against revenues. The impor-
tant costs of operation include: wages and salaries,
maintenance of and fuel for equipment, utilities,
depreciation and interest on buildings and equip-
ment, and overhead. Basic data for cost accounting
include the amount of waste disposed of at the fill,
either by the ton or cubic yard. A cost accounting
system recommended for use at a sanitary landfill
has been developed by the Office of Solid Waste
Management Programs.2
PERFORMANCE EVALUATION. In most cases,
there is a control agency at the State or local level
that determines if the operation is being conducted
in a manner that safeguards against environmental
pollution. To ensure a sanitary operation, the ad-
ministrative agency should conduct its own per-
formance evaluation. This should be done at the
administrative, not the operating or supervisory
level, and its requirements should be at least as
stringent as those of the higher control agency.
While operating and supervisory personnel should
know that these inspections will occur at specified
frequencies, they should not know the exact day.
This will help ensure a more representative inspec-
tion.
PERSONNEL. To secure and retain competent
employees, the administration must have a system-
atic personnel management plan. First a job de-
scription should be prepared for each position at
the sanitary landfill. A typical list of positions for a
large operation might include: (1) administrative
tasks (management, accounting, billing, engineer-
ing, typing, filing); (2) operating tasks (weighing,
operating equipment—spreading, compacting, ex-
cavating, hauling, road maintenance, dust control
53
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—maintaining equipment; traffic control, vector
control, litter control, site security).*
Once the job areas are defined, management
must determine how many employees are needed;
there may be some overlapping responsibilities. For
instance, a small sanitary landfill may need only
one operator to handle all its equipment. As the
size of the operation increases, a division of labor
will become necessary for sustained efficiency.
Governmental operations normally will have a
civil service system that defines hiring and career-
advancement procedures. In this case, manage-
ment's responsibility is to write good job descrip-
tions and interview applicants. A potential employee
should understand the job fully before he is hired.
If he is expected to perform other duties during
emergencies, he should be fully apprised of this
fact. Management must evaluate the ability of po-
tential employees to comprehend and perform their
tasks before they are hired.
Private operators may have more latitude in
their employment practices. They should also inter-
view and evaluate applicants as to interest in the job,
ability to do the work, and potential for increased
responsibility.
Once an employee is hired, management must
see that he is trained properly. Such training should
emphasize the overall operation of the landfill, safe-
ty, and emergency procedures. Employees responsi-
ble for more critical and complex tasks are given
more intensive training. Employees should thorough-
ly understand work rules as well as procedures for
handing out reprimands and submitting grievances.
Wages must be comparable with similar em-
ployment elsewhere. Larger operations may in-
crease employee satisfaction by providing lunch
room and locker facilities at the site. It is desirable
to have on-the-job training, insurance plans, pen-
sion plans, uniforms, paid holidays and vacation,
and sick leave programs.
PUBLIC RELATIONS. Public relations is one of
the manager's most important administrative func-
tions. Solid waste disposal sites represent an ex-
tremely emotional issue, particularly to those who
live in the vicinity of a proposed site. Many sites are
acceptable from an environmental control aspect but
are vigorously opposed by citizens who associate
them with old-fashion open or burning dumps. Con-
vincing the public of the advantages of a sanitary
landfill is a tedious process but can be accom-
plished by explanation and education. The program
should begin early in the long-range planning stages
and continue after operations begin. Public informa-
tion should stress that at a sanitary landfill the
waste is covered daily, access is restricted, insects
and rodents are controlled, and open burning is
prohibited. Examples of properly operated sanitary
landfills that have been accepted near residential
areas should be pointed out. Benefits to be de-
rived by using the completed site as a park or
playground, for example, should be emphasized.
The media available to the solid waste manager
are not limited to radio, television, billboards, and
newspapers, but include collection vehicles, col-
lectors, disposal facilities, and billing receipts. Help
provided by community organizations can do much
to increase public support. Extensive "stumping"
by elected and appointed officials in support of a
proposed solid waste disposal system is invaluable
if the speakers are knowledgeable and have suffi-
cient aids to help them, such as slides, films, and
pamphlets.*
The single most important factor for winning
public support of a solid waste disposal system is
an elected or appointed official who firmly believes
that it is acceptable and needed. A person willing to
accept the challenge of developing short- and long-
rarige plans and to see that they are properly imple-
mented is invaluable. Once these plans are devel-
oped and implemented, the disposal system must
be operated in a manner that upholds the high
performance of which it is capable.
A comprehensive solid waste management
plan should be developed, preferably on a regional
basis. Detailed design and operating plans should
cover a 10-year period and long-range, land-use
planning should be developed for 20 years. Appro-
priate locations for sanitary landfill sites can then
be identified, based on the needs of the area to
be served. These sites can be zoned for waste dis-
posal or other usage that will discourage develop-
ment of a residential area. The regional approach to
planning and implementation is especially desirable
because it often is more economically feasible for
all concerned. Land suitable for sanitary landfilling
is usually scarce or nonexistent within the jurisdic-
tion of a large city. Smaller communities nearby
may be able to provide the land and thus be able
to dispose of their own solid wastes in an accept-
able manner.
A key aspect of public relations is the proce-
dure for handling citizen complaints. Deficiencies
in operating methods or employee courtesy should
be investigated and acted on promptly. If this prac-
* Depending on the scale of operation, certain of these
tasks may be performed either on or off site.
' Information pamphlets on the entire spectrum of solid
waste management are available from the Office of Solid
Waste Management Programs and in a series of guides
issued by the National Association of Counties.
54
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tice is followed, citizens will be less hostile toward relatively inexpensive step communities can take
the operation, and employees will become more con- to provide a safe and attractive environment. By
scientious. proper design, operation, and management, sanitary
A sanitary landfill represents a positive and solid waste disposal can be provided.
REFERENCES
1. National Solid Wastes Management Association and Bureau of Solid Waste
Management. Sanitary landfill operation agreement and recommended
standards for sanitary landfill design and construction. [Cincinnati],
U.S. Department of Health, Education, and Welfare, 1969. 44 p.
2. ZAUSNER, E. R. An accounting system for sanitary landfill operations. Public
Health Service Publication No. 2007. Washington, U.S. Government
Printing Office, 1969. 18 p.
55
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BOOTH, E., and E. CARLSON. Rubber tires work well on sanitary landfills.
American City, 81(7):98-99, July 1966.
BOOTH, E. J., and D. KEAGY. How to operate sanitary landfill in really cold
weather. Public Works, 83(5):64-65, 102-103, May 1952.
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ACKNOWLEDGMENTS
The Office of Solid Waste Management Programs gratefully acknowledges
the many individuals who, over the past three years, assisted in developing
the outline and portions of the technical data contained in this publication
and those who graciously reviewed the numerous drafts.
Members of the ad hoc panel chaired by Mr. Ralph Black included: Donald
Anderson, L. W. Bremser, Dale Garst, Eugene Glysson, Orville Meyer, John
Parkhurst, Joseph Salvato, John Vanderveld, Jr., Jean Vincenz, and William
Warner. U.S. Public Health Service officers John Wheeler and Charles Reid
coordinated the first year efforts and assembled the initial data; the latter
also did much of the original work on finance and management.
Early drafts of this publication were reviewed by the American Society
of Civil Engineers; the American Public Works Association; the American
Public Health Association; the Consulting Engineers Council; the National
Solid Wastes Management Association; the U.S. Department of Health, Edu-
cation, and Welfare's Bureau of Community Environmental Management; the
Soil Conservation Service of the U.S. Department of Agriculture; the Bureau
of Land Management and former Federal Water Quality Administration of
the Department of Interior; the Department of Defense; and numerous State
health agencies.
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