GROUND WATER POLLUTION
FROM SUBSURFACE EXCAVATIONS
UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
Washington, D. C. 20460
1973
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PREFACE
The Federal Water Pollution Control Act, as amended
(33 U.S.C. 1251 et seq.; 86 et seq.; P.L. 92-500) instructs the
Administrator of the Environmental Protection Agency to issue
information including processes, procedures, and methods to
control pollution resulting from the disposal of pollutants in
wells or in subsurface excavations (Section 304(e)(D)).
This report is issued pursuant to that legislative mandate
in an attempt to shed some light on the problems of the pollution
of underground water.
/
c?
*uisell E. Train
Administrator
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EPA 430/9 73 012
GROUND WATER POLLUTION
FROM SUBSURFACE EXCAVATIONS
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Water Quality and Non Point Source Control Division
Washington, D.C. 20460
1973
For sale by the Superintendent of Documents, U.S. Government Printing OfflCfc, Washington, D.C. 2M02 • Price $2,25
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FOREWORD - WATER QUALITY
In order to avoid undesirable changes in ground water
quality, that quality must first be established. Consider
the discussion of the term "quality" provided by P. H.
McGauhey (1968) .
"The idea that 'quality' is a dimension of water that
requires measurement in precise numbers is of quite
recent origin. Ancient British common law...was content
to state that the user of water was not entitled to
diminish it in quality. But the question of what
constituted quality was neither posed nor answered.
...A precise definition of water quality lay a long way
in the future.
"More than half a century ago a Mississippi jurist said,
•It is not necessary to weigh with care the testimony of
experts -- any common mortal knows when water is fit to
drink.* Today we find it necessary to enquire of both
common mortal and water expert just how it is that we
know when water is fit for drinking. Moreover, in the
intervening years, interest in the 'fitness1 of water
has gone beyond the health factor and we are forced to
decide upon its suitability for a whole spectrum of
beneficial use involving psychological and social, as
well as physiological goals.
"Looking back on the history of water resource
development, one is impressed that under pioneer
conditions it was usually sufficient to define water
quality in qualitative terms, generally as gross
absolutes. In such a climate, terms such as swampwater,
bilgewater, stumpwater, blackwater, sweetwater, etc.,
produced by a free combination of words in the English
language, all conveyed meaning to the citizen going
about his daily life. 'Fresh1 as contrasted with 'salt1
water was a common differentiation arising from both
ignorance and a limited need to dispel it. If a ground
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or surface water was fresh, as measured by the human
senses rather than the analytical techniques of chemists
and biologists, it little occurred to the user that it
was any different than rainfall in producing crops."
As the author has noted elsewhere (McGauhey, 1961; 1965)
"A need to quantitate, or give numerical values to, the
dimension of water known as 'quality1 derives from
almost every aspect of modern industrialized society.
For the sake of man's health we require by law that his
water supply be 'pure, wholesome, and potable.' The
productivity and variety of modern scientific
agriculture require that the sensitivity of hundreds of
plants to dissolved minerals in water be known and
either water quality or nature of crop controlled
accordingly. The quantity of irrigation water to be
supplied to a soil varies with its dissolved solids
content, as does the usefulness of irrigation drainage
waters. Textiles, paper, brewing, and dozens of other
industries using water each have their own peculiar
water quality reeds. Aquatic life and human recreation
have limits of acceptable quality. In many instances
water is one of the raw materials the quality of which
must be precisely known and controlled.
"With these myriad activities...going on simultaneously
and intensively, each drawing upon a common water
resource and returning its waste waters to the common
pool, it is evident to even the most casual observer
that water quality must be identifiable and capable of
alteration in quantitative terms if the word is to have
any meaning or be of any practical use.
"Thus it is that those unwilling to go along with the
Mississippi jurist must express quality in numerical
terms.
"The identification of quality is not in itself an easy
task, even in the area of public health where efforts
have been most persistent. For example, the great
waterborne plagues that swept London in the middle of
the nineteenth century pointed up water quality as the
culprit; yet it was another quarter of a century before
the germ theory of disease was verified, and more than
half a century before the water quality requirements to
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meet it were expressed in numbers. Even in 19 OU, when
our Mississippi jurist spoke, children still died of
•summer sickness1 (typhoid) often ascribed to such
things as eating cherries and drinking milk at the same
meal; and scarcely a family escaped the loss of one of
its members by typhoid fever. Yet when it came to
defining the water quality needed to avoid this, the
best we cculd do was to place on some of the 'fellow
travelers' of the typhoid organism numerical limits
below which the probability of contracting the disease
was acceptably small. Nor has this dilemma been
overcome. In 1965, an outbreak of intestinal disease at
Riverside, California, which afflicted more that 20,000
people and caused several deaths, was traced to a new
comer (Salmonella tyjDhimurium) in a water known to be
safe by 'experts' watching the coliform index. So once
again the search begins for a suitable description of
quality.
"A second dilemma which survived the struggles that
codified and institutionalized our concepts of water
quantity lies in the definition of the word 'quality.'
While the dictionary may suggest that quality implies
some sort of positive attribute or virtue in water, the
fact remains that one water's virtue is another's vice.
For example, a water too rich in nutrients for discharge
to a lake may be highly welcome in irrigation; and pure
distilled water would be a pollutant to the aquatic life
of a saline estuary. Thus, after all the impurities in
water have been cataloged and quantified by the analyst,
their significance can be interpreted in reference to
quality only relative to the needs or tolerances of each
beneficial area to which the water is to be put.
"Shakespeare has said, 'The quality of mercy is not
strained...1 And Indeed it is not as long as mercy is
defined in qualitative terms. One can but imagine the
problems which might arise if it were required that
justice be tempered with 1.16 quanta of mercy in one
case and 100 quanta in another. Yet this is precisely
what confronts us in establishing measures of the
dimension of quality of water."
111
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References
McGauhey, P.H., "Folklore in Water Quality Standards,"
SJkZii Engineering, Vol. 3, No. 6, New York, June
(1965).
McGauhey, P.H., "Quality - Water's Fourth Dimension,"
Proceedings of the Water Quality Conference, University
of California, Davis, California, January 11-13 (1961) .
3. McGauhey, P.H. , j?H3inee_rjLnc[ Management of W^ater Quality,
McGraw-Hill Series insanitary Science and Water
Resources Engineering, McGraw-Hill, Inc., New York, New
York (1968) .
IV
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CONTENTS
Page
FOREWORD -WATER QUALITY i
ILLUSTRATIONS X
TABLES Xi
PART ONE
SOURCE IDENTIFICATION AND EVALUATION
INTRODUCTION 1
Pollution Mechanisms 2
Current Involvement 12
Current Practices 13
Sources of Contaminants 14
Types of Contaminants 16
Methods of Pollutant Transport 17
Magnitude cf Pollution 18
Prediction Methods 18
SUMMARY AND CONCLUSIONS 21
References 23
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PART TWO
CONTROL METHODS, PROCESSES, AND PROCEDURES
Page
SECTION I - INTRODUCTION 24
Public Law 92-500 24
GROUND fcATER QUALITY AND POLLUTION 25
Occurrence of Ground Water 27
Control by Elimination of 29
Pollution Sources
SECTION II - POLLUTION FROM WELLS 31
INDUSTRIAL WASTE INJECTION WELLS 31
Current Situation 34
Environmental Consequences 42
Contamination of Fresh Ground Water 43
Contamination of Other Subsurface
Resources 46
Earthquake Stimulation 46
Control Methods 47
Local Site Evaluation 51
Waste Evaluation 57
Well Construction and Evaluation 61
Aquifer Response and Wastewater
Movement 67
Operating Program 68
VI
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Surface Equipment and Emergency
Procedures 69
Monitoring Procedures 72
State Programs 74
OTHER WELLS 80
Petroleum Industry Wells 80
Geothermal Energy Wells 86
Wells for Injection of Sewage
Effluent and Desalination Plant
Brines 89
Radioactive Waste Disposal Wells 90
Gas Storage Wells 91
Water Wells 93
Dry Holes and Abandoned Wel}.s 95
References 96
INJECTION INTO FRESH WATER AQUIFERS 101
Scope of the Problem 101
Environmental Consequences 105
Nature of Pollutants 106
Pollution Movement 110
Examples of the Use of Injection
Wells 113
Control Methods 116
Monitoring Procedures 120
Vll
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References 121
SECTION III - POLLUTION FROM OTHER SUBSURFACE
EXCAVATIONS 123
LAGOONS, BASINS, AND PITS 123
Scope of the Problem 125
Potential Hazard to Ground Water 127
Control Methods 130
Monitoring Procedures 132
References 134
SEPTIC SYSTEMS 136
Scope of the Problem 136
Environmental Consequences 139
Control Methods 142
Monitoring Procedures 147
References 150
LANDFILLS 151
The Matter Of Definition 151
Environmental Consequences 152
Leaching of Landfills 156
Nature and Amount of Leachate 160
Control Methods 167
Monitoring Procedures 173
References 175
vxn
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SEWER LEAKAGE 178
Scope of the Problem 178
Causal Factors 179
Environmental Consequences 180
Control Methods 184
Monitoring Procedures 185
TANK AND PIPELINE LEAKAGE 186
Scope of the Problem 186
Radioactive Wastes 187
History 188
Leakage in the United States 188
Environmental Consequences 191
Causal Factors 194
Pollution Movement 196
Control Methods 198
Monitoring Procedures 209
References 215
APPENDIX
ADMINISTRATOR'S DECISION STATEMENT NO. 5 I
RECOMMENDED DATA REQUIREMENTS FOR EVALUATION OF
SUBSURFACE EMPLACEMENT OF FLUIDS BY WELL INJECTION IV
IX
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ILLUSTRATIONS
Figure Title
A Geologic features significant in 50
deep waste-injection-well-site evaluation,
and locations of industrial-waste injection
systems (Warner, 1968) .
B Schematic diagram of an industrial 66
waste injection well completed in
competent sandstone (modified after
Warner, 1965).
C Diagram of domestic sewage disposal 103
system employing a disposal well in the
middle Eeschutes Basin, Oregon
(Sceva, 1968) .
D Hypothetical pattern of flow of 112
contaminated water injected
through wells into water table and
artesian aquifers (Deutsch, 1963).
E Area contaminated by subsurface 199
gasoline leakage and ground water
contours in the vicinity of Forest
Lawn Cemetery, Los Angeles County,
as of 1971 (Williams and Wilder, 1971) .
F Experimental results from Switzerland on... 203
the distribution of oil in soil as a function
of time (Todd, 1973) .
G Swedish two~pump method for removal of oil 206
pollution from a well (Todd, 1973).
H Oil interceptor 207
ditch.
I Oil skimming.. 208
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TABLES
Table Tiii§ Page
1 Distribution of existing industrial. ...... 37
wastewater injection wells among the 22
states having such wells in 1972
(Warner, 1972) .
2 Distribution of injection wells by ........ 37
industry type (Warner, 1972) .
3 Operational status of industrial .......... 38
injection wells (Warner, 1972) .
U Total depth of industrial injection ....... 38
wells (Warner, 1972) .
5 Rate of injection in industrial.. ......... 39
wells (Warner, 1972) .
6 Pressure at which waste is injected....... 39
in industrial wells (Warner, 1972) .
7 Type of rock used for injection ..... „ ..... UO
by industrial wells (Warner, 1972) .
8 Age of injection zone of industrial ....... 40
wells (Warner, 1972) .
9 Factors fcr consideration in the geologic 52
and hydrologic evaluation of a site for
deep-well industrial waste injection.
10 Factors to be considered in evaluating.... 58
the suitability of untreated industrial
wastes for deep-well disposal.
11 Summary of information desired in... ...... 64
subsurface evaluation of disposal horizon
and methods available for evaluation.
12 Selected chemical-quality characteristics 109
of native water and tertiary treated
injection water (Vecchiolo and Ku, 1972) .
XI
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13 Components of domestic solid waste 154
(expressed as percentages of total).
14 Landfill disposal of chemical process 155
wastes.
15 Composition of municipal refuse 157
16 Leachate composition 162
17 Change in leachate analysis with time..,.. 165
(Meichtry, 1971) .
18 Ground water quality 173
19 Summary of interstate liquid pipeline 192
accidents for 1971 (Office of Pipeline
Safety, 1972 ).
20 Range of annual pipeline leak losses 193
reported on DOT Form 7000-1 for the
period 1968 through 1971.
21 Frequency of causes of pipeline leaks 195
in 1971 (Office of Pipeline Safety, 1972).
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PART ONE
SOURCE IDENTIFICATION AND EVALUATION
INTRODUCTION
"Ground water quality" is the name of the game in a
discussion of subsurface excavations as sources of
pollution. In rare instances pollution from subsurface
excavations moves directly to surface water bodies without
entering the ground water domain. To the extent that ground
water moves to the surface, which is considerable, polluted
ground water causes surface water pollution, but it is the
alteration of the chemical, physical, biological and
radiological integrity of ground water that is the
overriding concern.
Identification of the nature of polluting excavations starts
from the premise that every hole in the ground, whether
natural or man-made, is a potential source of ground water
contamination. A "well" is a particular type of subsurface
excavation rather than merely, "a place from which water
issues forth" as it was described in ancient England where
the word originated.
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Pollution_Mecbanisms
There are three basic mechanisms by which ground water
becomes polluted:
1) The natural filtering system of vegetation, soil,
silt, sand, gravel and rocks that protects ground
water is bypassed by polluting substances.
2) The natural filtering system is overwhelmed by a
concentration of polluting substances beyond its
capacity to handle them, or by substances that are
unfilterable.
3) The hydraulic or chemical balance in the subsurface
is altered so that polluting substances move to,
within or between aquifers to change water quality.
Case 1: System bypassed
Whether a hole is natural, dug by hand, drilled, blasted,
mined or otherwise excavated; and whether a hole is intended
for the producticn of a resource, the emplacement of a
waste, the storage of a product, the collection of
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information or the emplacement of hardware; it penetrates at
least a portion of the surface filtering system, thus
providing a possible avenue for contaminants to bypass that
system. The polluting substances that can and do enter
aquifers as a result of these activities include most of the
elements in the periodic table in nearly every combination
known to man.
Subsurface excavations may be grouped into categories based
on a description of the excavation:
• Wells and vertical, drilled holes:
Includes water wells, oil wells, gas wells, dry
holes, core holes, shot holes, stratigraphic tests,
waste injection wells, product injection wells,
secondary recovery injection wells, solution mining
wells, dewatering wells and observation wells.
• Sanitary facilities:
Includes septic tanks, cess pools, latrines and dry
wells.
• Underground mines and tunnels:
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Includes highway, railroad and storage tunnels.
• Construction excavations:
Includes piling holes, basement excavations, river
and harbor dredging, and sand drains.
• Quarries and strip-mines:
Includes rock quarries, sand pits, gravel pits,
strip mines and natural sinkholes.
• Burial vaults:
Includes buried pipe lines and buried tanks.
• Pit silos and land fills.
A broader grouping, based on the intended use of the
excavations, is also useful in terms of ground water
pollution considerations.
• Extraction:
Producing wells, mines, quarries, and sand and
gravel pits.
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• Injection:
Waste disposal, mineral recovery, secondary mineral
recovery and product storage.
• Other:
Dry holes, stratigrapbic tests, shot holes, core
holes, construction excavations, burial vaults,
sink holes etc.
The evaluation of the extent of the occurrence of potential
sources is a matter of a thorough physical inventory,
bearing in mind that subsurface pollution is a four
dimensional problem involving three dimensional space, and
time. As an example, a waste injection well may introduce,
through a twenty centimeter diameter hole in the ground,
highly toxic materials into several subsurface reservoirs
that are more than a kilometer apart vertically but are
directly beneath that twenty centimeter surface area. The
waste may be directed into a useless, salty aquifer at a
depth of 3800 meters below the land surface where it will
cause pollution in the strict sense of the word, as defined
in P.L. 92-500, but may cause no environmental problems anc
never again be detected in the biosphere. However an
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excessive injection rate (volume divided by time) can cause
pressures that will fracture the overlying rock, or the
cement around the well casing, or the casing itself and
permit the wastes to enter a fresh-water aquifer only two
hundred meters below the land surface. Additional pollution
problems can result from the corrosive deterioration of the
well casing near the surface where water-table aquifers can
be polluted at depths of fifteen meters or less. The
measurable effects of the change in water quality of the
3800 meter aquifer may last for centuries but may have no
adverse effects and never be known. The pollution of the
200 meter aquifer, or the 15 meter aquifer, may occur at any
time during the waste injection, may be detected at anytime
from a few days to many years after the injection commences,
and may last for many decades, moving at a rate of less than
30 centimeters a year.
It is useful to establish priorities of consideration in the
initial stages of an inventory program so that aquifers are
dealt with in the order of their importance and sources of
massive pollution receive first consideration with the
effect on human health as the leading criterion.
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The nature of the sources of ground water pollution may be
established in any political, geographic, administrative or
hydrologic region by an inventory of: the regional
activities that make or use holes in the ground; the types
of holes used or made; their design and construction; and
their location. The regional extent of such sources may
then be determined by an inventory, by category, of these
holes and the use made of them, followed by an analysis of
the data thus obtained.
The location of the hole in three dimensional space is
critical in that the likelihood and magnitude of ground
water pollution resulting from a properly constructed
subsurface excavation is largely dependent on the amount and
type of material between the aquifers and the contaminant at
its point of release.
Much relevant information must be developed to aid in
assessing the pollution potential of the most sophisticated
type of injection well injecting large volumes of various
hazardous materials. It is unlikely that all of the
information considered to be relevant for the sophisticated
case would be required for many particular subsurface
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excavations, but the minimum location information required
for all the general cases would include the name and address
of the party responsible for the generation of the
contaminant, the location of the excavation in terms of
surface geography (State, County, Survey, Section, Township,
Range, latitude, longitude and surface elevation with
respect to sea level) the location of the contaminant in
terms of subsurface geology (depth of excavation, depth to
top and bottom of aquifers, depth to bedrock, depth to top
and bottom of aquicludes, depth to top and bottom of
injection zone and types of rocks involved).
Design and construction details are necessary to evaluate
the excavations pollution potential. These may range from
knowing whether or not an excavation is lined with a low
permeability material (in the case of an evaporation pond),
to the case of a waste injection well which would require
design and construction information such as specifications
for all strings cf casing and tubing, cement, pumps,
pressure monitoring equipment, injection rate monitoring
equipment, contingency equipment, and surface valves and
piping plus details of hole diameters, casing types, casing
lengths, casing seats, cementing program, contingency
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program, monitoring program, testing and completion programs
and geologic formations penetrated.
Case 2: System overwhelmed
A hole in the ground is not required for this type of
pollution to occur, but the collection of pollutants in a
subsurface excavation does provide the ultimate
concentration of materials and can cause the filtering
system to fail (in the case of materials that would
ordinarily be filtered out by the soil), or can cause a
concentration of unfilterable pollutants (such as phenols)
to move into aquifers. settling ponds, evaporation ponds
and waste lagoons are among the offenders in this category.
Case 3: Hydraulic or chemical balance altered
Any subsurface excavation that is used to move fluids into
or out of the ground will have an effect on the hydraulic
balance of the aquifers involved. The effect may be so
slight as to be immeasurable or may be so great as to cause
the fluid in a porous formation to treak out into other
porous formations cr to the surface.
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Injected fluid need not be a pollutant to cause serious
ground water pollution. For example, cooling water of
excellent chemical quality may be injected into an aquifer
containing salt water at its lower end in order to avoid
causing a damaging temperature rise in a surface stream.
The resulting pressure change can:
• Cause the salt water to move into fresh-water
portions of the same aquifer and into water wells.
• Cause the salt water to move into other fresh-water
aquifers and into water wells.
• Cause the salt water to move into surface-water
bodies.
The extraction of fluid also alters the hydraulic balance
and can cause the irovement of subsurface pollutants in and
between aquifers and surface waters. For example, a
municipal water-well field pumping many millions of liters
per day may cause seawater to move inland in an aquifer
several kilometers further than it normally appears and thus
pollute municipal wells and other wells in the vicinity.
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Likewise, an industrial well pumping high quality process
water from the top 15 meters of an aquifer can cause the
upward coning of deeper salt water in the same aquifer,
resulting in the pollution of the well supply. These
effects are treated more fully in the discussion of "Salt-
Water Intrusion." 7 Pollution may also result from a similai
lowering of pressure in a confined aquifer, causing the
compression of an overlying confining bed and resulting in
the "wringing out" of highly mineralized water from the
confining bed into the aquifer. Arsenic pollution is known
to have resulted from just such a situation.
Instances of ground water pollution have been noted that
were attributed to a waste injection-caused change in pH and
temperature (chemical balance alternation). The pollution
resulted, not from concentrations in the aquifer of the
injected material, but from an "unloading effect" that
occurred when the sorptive characteristics of a formation
that had trapped a toxic waste constituent from some other
source were changed by exposure to the injected material and
the toxic constituent was released into the ground water.
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Current__Involvement
An inventory of the disposal of wastes into holes in the
ground can be commenced by investigating federal waste
disposal practices. A 1960 inventory1 covering waste water
disposal practices, under the category "ground disposal,"
reports more than 11,000 such activities, most of which
involve subsurface excavations (septic tanks, cesspools,
subsurface disposal fields, privy vaults, chemical toilets,
sewage lagoons and wells).
Other government entities in the subsurface disposal
business include the State equivalents of the Federal
departments as well as the various regional, county,
township and city organizations that generate wastes.
The private sector also warrants consideration with special
attention being paid to the industries that use well
injection as a means of disposing of large volumes of
noxious and obnoxious wastes2. These include power plants,
steel mills, metal plating establishments, waste treatment
plants, pharmaceutical laboratories, food processing plants,
paper mills, and the petroleum industry and its exploration,
production, refining and chemical manufacturing operations.
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Other private sector sources include real estate
developments, agricultural units, the operators of large
buildings and countless rural and vacation home sanitary
facilities.
Current Practices
The uses made of wells and other subsurface excavations for
the disposal of wastes range in terms of volume from nearly
27,000 kiloliters a day to less than 200 liters, and in
terms of health hazard, from dangerous (e.g., certain
radioactive materials) to benign (air conditioning cooling
water) .
The subsurface disposal of radioactive materials has
occurred on an operating or experimental basis in several
states. The methods used or considered include pit burial,
well injection into high porosity, well injection into low
porosity formations and salt-mine entombment.
Brines produced in association with crude oil, natural gas
and steam are normally disposed of by well injection, often
into the rock formation and zone from which they were
extracted, but mere often either into a deeper, non-
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productive portion of the formation from which they were
extracted or intc seme other rock formation. There are tens
of thousands of these wells in the oil producing states.
Man made-brines are also handled in a similar manner though
of course they, being produced at surface sources, do not.
have a partially depleted underground reservoir to which to
return 3 .
Raw sewage, treated sewage and hot water resulting from
various cooling processes are also being disposed of by well
injection. Much material of all kinds is thrown, spilled,
dumped, leaked or merely left "lying around" in rock
quarries, sand and gravel pits, and construction
excavations.
.__ of_ Contaminants
Vast areas of the United States that produce crude oil and
natural gas are underlain by huge volumes of contaminated
ground water. The exploration for and the exploitation of
fluid hydrocarbons involve multiple sources of
contaminants4. The pre-drilling exploration activities
frequently include seismic surveys that make many holes in
the ground. Exploration and production drilling make larger
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and deeper holes. secondary and tertiary recovery
activities require the use of injection wells, as does the
disposal of brines.
The nations petrochemical industry in its production phase
also utilizes waste injection wells and settling pits, as do
steel mills, metal plating establishments, pharmaceutical
laboratories, feed processing plants, paper mills, oil
refineries, sewage-treatment plants, water-treatment plants,
certain agricultural cooperatives and geothermal power
producers.
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Types_Qfi Contaminants
Natural brines produced in association with crude oil and
natural gas are a type of contaminant with a varied and
complex chemistry4 that most commonly includes greater than
trace amounts of sodium, calcium, magnesium, potassium,
barium, strontium, iron, sulphur, bromine and dissolved
gasses such as carbon dioxide, hydrogen sulfide and methane.
Natural brines produced in geothermal exploitation are
similarly constituted but often contain much more lithium,
flourine, silica, arsenic and radioisotopes.
Man-made pollutants that are regularly introduced into the
subsurface through well injection or other means include
acids, chromates, phosphates, alcohols, sulphates, nitrates,
bromine, chlorine, tin, aldehydes, pyrrolidone, ketones,
phenols, potassium, acetates, benzene, cyclohexane, hydrogen
cyanide2 and many ethers (identified and unidentified) that
are being pumped, dumped and spilled into the earth.
Sewage, with the associated bacteria and viruses, is also on
the list.
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Methods of Pollutant^Transgort
Pollutants in solution move away from wells and other
subsurface excavations into aquifers, or to the surface,
along the paths cf least resistance. Commonly, the zone of
fluid movement from a well or other subsurface excavation is
a naturally occurring unconsolidated sand or gravel5 in
which fluid moves between the grains in a characteristic
manner that lends itself to rather precise mathematical
modeling which yields reasonably straightforward predictive
information.
Consolidated rocks usually exhibit more complex types of
porosity with fluid movement through solution-caused pores
or channels, or stress-caused joints and fractures. In some
instances the movement is uniform and therefore predictable,
but in many instances it is not. The same is true of man-
made fractures and channels (the result of high pressure
fluid injections, the injection of solvents and subsurface
explosions) .
Subsurface excavations are, in themselves, potential paths
for the vertical movement of fluids. Uncased and poorly
cased holes provide direct avenues for the movement of
17
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pollutants from the surface to aquifers, from waste
injection zones to the surface, and from waste injection
zones to other aquifers. Excessive injection pressures
aggravate any tendency for fluid to escape through casing-
thread leaks, pinhole leaks or channels in the casing
cement.
Magnitude^of Pollution
Studies of the magnitude of ground water pollution have been
made by governmental and private groups including the
Envrionmental Protection Agency, the U.S. Geological Survey
and other Department of the Interior groups, the Atomic
Energy Commission, the American Asspciation of Petroleum
Geologists, the American Institute of Mining Engineers, the
Interstate Oil Compact Commission and many others. The
EPA's "subsurface Water Pollution - A Selective Annotated
Bibliography," Part I, II and III lists hundreds and is
available from the EPA's Office of Water Program Operations,
Washington, D. C. 20U60 .
Prgdiction_Methgds
The problems of designing, constructing and operating
subsurface waste-disposal facilities properly are quite
18
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complex, requiring consideration of the interacting physical
and chemical character of: the construction and operating
materials, the wastes involved, the geologic formations that
will receive them, and the fluids naturally present in those
formations.
Various predictive techniques are useful in attacking the
problems that result from subsurface waste disposal and, as
with other subsurface problems, no one method will provide a
complete answer.
The basic tools for predicting the location and extent of
subsurface pollution are waste surveys and hydrogeological
studies, the former to determine the volume and nature of
the materials being introduced into the subsurface, and the
latter to assist in assessing the results; for example, the
existence of an operating steel mill guarantees the
accumulation of a certain amount of used pickling liquor
which, if it finds its way into a good quality surface or
subsurface water, is a pollutant. The liquor may be
recycled for the removal of usable materials to the extent
that it is acceptable as a component of an authorized
effluent discharge to a surface stream. It also may be
19
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piped, untreated, to an injection well and placed
underground, A waste survey indicating the existence of the
steel mill will thus alert investigators to a pollution
threat. Such a survey will also establish similar threats
from a high concentration of Septic tanks, brine injection
wells, food processing plants, and other waste generating
activities.
Existing hydrogeological studies made by private, municipal,
county, state or federal groups will often yield enough
information to establish the areas of likely ground water
contamination resulting from waste disposal activities.
Additional empirical evidence will come via complaints from
well and spring users whose water supplies have developed
taste, odor, sediment or color problems. Local health
records may also indicate ground water pollution. A ground
water quality monitoring system may exist in the area and
yield precise information on the results of the disposal of
the waste. Mathematical and analog modeling of the
subsurface excavation and the aquifers involved may
contribute quite reliable data on the fate of the wastes and
indicate where tc look for ground water pollution. Various
geophysical investigations (e.g., seismic surveys and well
20
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logging) are often the most convenient way to reinforce both
empirical and theoretical investigations.
SUMMARY AND CONCLUSIONS
Ground water supplies a significant proportion of the total
amount of fresh water withdrawn* for use in the United
States (21.4% in 1970); it supplies more than 34% of the
nation's public water supply needs, more than 36% of the
crop-irrigation water withdrawn, and from 47% to 83% of the
total water withdrawals in eleven of our larger states.
As the control of discharges of pollutants into surface
waters becomes more effective, the temptation to go to
subsurface discharges becomes stronger. An increased and
continuing awareness of what is being placed, intentionally
or inadvertently, in wells and other subsurface excavations,
and where it is going, is essential if we are to prevent the
widespread pollution of our ground water resources.
The use of subsurface excavations for the disposal of wastes
is growing, the types of materials so disposed of are
legion, and the placement and isolation of these materials
21
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so as to avoid adverse environmental impacts (particularly
ground water quality degradation) is a difficult and
complicated problem.
The states, in order to avoid the long-term pollution of
huge quantities of usable water, must continue to devote
careful and expert attention to the protection of the
subsurface environment to assure their citizens of a
continuing supply cf good quality ground water at the least
cost.
22
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References
1. U.S. Department of Health, Education, and Welfare, Waste
Water Disposal Practices at Federal Installations as of
December |I7 I960, Vol. 54, 55, 56', 57, 58.
2, Warner, Don. L., Survey of Industrial Waste Injection
Wells, U.S. Geological Survey (1972). ~^~
3. Research Committee, Interstate Oil Compact Commission,
Production and Disposal of Oilfield Brines in the United
States and Canada, Interstate Oil Compact Commission,
Oklahoma City, Ok., (1960).
4. Collins, A. Gene, Oil and Gas Wells - Potential
Polluters of the Environment? Water Pollution Control
Federation Journal, Washington, D. C. 20016, Vol. 43,
No. 12, pp 2383-2393 (Dec. 1971).
5. Walton, William C., Groundwater Resource Evaluation,
McGraw-Hill, (1970).
6. Murray, Richard C. and Reeves, Estimated Use of Water in
the United States in 1970r U.S. Geological Survey,
Washington, D.~c7, 20242 (1972) .
7. Environmental Protection Agency, Identification and
Cgntrgl of Pollution from Salt Water Intrusion^
Washington,~E.C. 20460(1973).
23
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PART TWO
CONTROL METHODS, PROCESSES, AND PROCEDURES
SECTION I - INTRODUCTION
gublic Law 92-500
Section 304 (e) of Public Law 92^500, the Federal Water
Pollution Control Act Amendments of 1972, provides that
"The Administrator (of EPA)...shall issue...within one
year after the effective date of this subsection (and
from time to time thereafter) information including (1)
guidelines for identifying and evaluating the nature and
extent of nonpcint sources of pollutants, and (2)
processes, procedures, and methods to control pollution
resulting from (D) the disposal of pollutants in wells
or in subsurface excavations.
The treatment of this topic is not intended to be
exhaustive, since this would take many volumes. Rather, the
intent is to be as concise as possible, addressing those
aspects felt to be most important, with liberal use of
selected references to more detailed explanations.
-------
GROUND WATER QUALITY AND POLLUTION
The quality of ground water refers to its chemical,
physical, and biological characteristics. All ground water
contains dissolved solids and possesses characteristics such
as temperature, taste, and odor. Some contain pathogens
such as bacteria and viruses. The natural quality of ground
water depends upcn its environment, movement, and source?and
in different localities, major contrasts in natural quality
can be noted. Ground water temperatures may range from a
few degrees above freezing in cold climates to considerably
above the boiling point in thermal-spring sources, while
salinities may range from near zero in newly infiltrated
precipitation to several hundred thousand milligrams per
liter in underground brines.
For the purposes of this report, ground water pollution is
defined as the man-made or man-induced alteration of the
chemical, physical, biological, and radiological integrity
of ground water. Such pollution is caused, as we would
expect, by the introduction into aquifers of pollutants.
Pollutants are defined in Public Law 92-500 to include,
among other things, all industrial wastes except, "water.
25
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gas, or other material which is injected into a well to
facilitate production of oil or gas, or water derived in
association with oil or gas production and disposed of in a
well, if the well used either to facilitate production or
for disposal purposes is approved by authority of the State
in which the well is located, and if such State determines
that such injection or disposal will not result in the
degradation of ground or surface water resources." The
particular use to which a ground water can be put depends,
of course, upon its quality. However, the various criteria
defining the suitability of a ground water for municipal,
industrial or agricultural use are not considered in
describing pollution. Instead, the measure of pollution is
the measure of the detrimental change in the given natural
quality of ground water. This may take the form, for
example, of an increase in chloride content, of a rise in
temperature, or of the addition of pathogens.
Programs to control ground water pollution are based upon
the growing realization that both ground water and the
underground space in which it is stored are valuable natural
resources to be conserved by preventing, reducing, and
eliminating pollution.
26
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Occurrence of Ground Water
Ground water forms a part of the hydrologic cycle. It
originates as precipitation or surface water before
penetrating below the ground surface. Ground water moves
underground toward a natural discharge point such as a
stream, a spring, a lake, or the sea, or toward an
artificial outlet constructed by man such as a well or a
drain.
An aquifer is a formation, group of formations, or part of a
formation that contains sufficient saturated permeable
material to yield significant quantities of water to wells
and springs (USGS 1972). The most common aquifers are those
consisting of unconsolidated alluvial materials such as
gravel, sand, silt, and clay. Other important aquifers
occur in coal, sandstones, limestones, volcanic rocks and
other igneous rocks.
The water table is that surface in an unconfined water body
at which the pressure is atmospheric (USGS 1972). Below the
water table the permeable soil or rock is saturated with
water. Unconfined ground water is water in an aquifer that
has a water table, whereas confined ground water is under
27
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pressure significantly greater than atmospheric, and its
upper limit is the bottom of a bed of distinctly lower
hydraulic conductivity than that of the material in which
the confined water occurs (USGS 1972) .
Ground water typically flows at rates of from 20 centimeters
per year to 2 meters per day. Above the water table the
flow direction is generally downward, but below the water
table in the main ground water body, the movement is lateral
and governed by the local hydraulic gradient. Once a
pollutant is introduced into an aquifer it tends to move in
the same direction as the incorporated ground water and at a
velocity equal to or less than that of the ground water.
Pressure changes, in contrast, travel at or near sonic
speed. With time and distance traveled, pollutants decrease
in concentration, resulting from dilution, filtration,
adsorption, precipitation, decay (e.g., radioactive
isotopes), and death (e.g., bacteria). From a point source
of pollution, plumes of various shapes are often detected
extending downgradient within the aquifer and gradually
dissipating with distance.
28
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of __Polluticn_ Sources
For any source or cause of pollution, an obvious control
method would be to eliminate entirely the source or the
cause itself. This method, however, is not possible in many
situations and thus becomes a trivial solution. To
illustrate the point, one method for controlling pollution
from septic tanks would be simply to eliminate all septic
tanks. To completely eliminate the millions of septic tanks
in the United States would require alternatives that are not
realistic or feasible. These may include, for example:
• Installing sewer systems to replace septic tanks —
economically infeasible in many rural areas.
• Replacing septic tanks with individual home waste
treatment and desalination plants — technically
and economically infeasible at the present time.
• Moving people to sewered areas -- socially,
legally, and politically infeasible.
Thus, the control methods that are described for septic
tanks include not only the possibility of requiring sewers
but also deal with regulating their construction, their
29
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location as regards subsurface conditions and topography,
their density, their operation, and their maintenance. The
latter measures, while not eliminating ground water
pollution, will reduce it and will prevent it from exceeding
prescribed levels.
The suggestion that the source or cause of pollution be
eliminated is not repeated for each of the sources and
causes that are discussed. In general, the control methods
that are suggested and discussed are those believed to be
realistic and feasible. Clearly, the applicability of the
suggested methods will depend upon local situations.
In situations involving the intentional placement of
pollutants in subsurface excavations, control methods
involve measures to assure the isolation of the pollutants
from the biosphere. The six steps essential to this end,
which are developed in this report, are:
• Siting » Monitoring
• Design « Abandonment
• Construction
• Operation
30
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SECTION II - POLLUTION FROM WELLS
This section considers ground water pollution resulting from
the injection of fluids into the earth, the extraction of
fluids from the earth, and other aspects of ground water
pollution resulting from the construction and use of wells.
Primary emphasis is placed on the subsurface emplacement of
industrial wastes by well injection. Wells for this
purpose, commonly referred to as "waste disposal wells," are
a relatively recent development and are becoming
increasingly popular as restrictions on the discharge of
noxious and obnoxious fluids to surface waters become more
stringent.
INDUSTRIAL WASTE INJECTION WELLS
The potential of wells for the subsurface disposition of
industrial wastes was recognized and exploited by at least
one company as early as 1928. The extent of such use
outside the oil industry was small until the 1960»s when
31
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increasing emphasis on surface water polluton control
prompted companies to seek other alternatives for waste
water releases, one of which was well injection.
As of mid 1972 at least 246 such wells had been constructed
in the United States (Warner, 1972). This number is
relatively small, but the volume of waste involved, and its
potency, has caused considerable concern to be expressed
about the use of injection wells. The technical reasons for
this concern include the following:
Some of the wastes that are being injected contain
chemicals that are relatively toxic and will
persist indefinitely in the subsurface environment.
Monitoring of the subsurface environment is quite
difficult in comparison with monitoring of the
surface.
If contamination of usable ground water or other
resources should occur, decontamination may be
difficult or impossible to effect.
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Why should such wells be used at all in view of these and
other possible objections? If the alternatives are examined
that are available for ultimate disposition of waste waters
containing dissolved inorganic chemicals, relatively
nondegradable dissolved organic chemicals, or combinations
of these, it is found that they are limited to disposal to
the ocean, disposal to the land surface, disposal to fresh
waters, storage, incineration, recovery of the chemicals for
reuse, or subsurface injection. Of these alternatives,
subsurface injection may be the most satisfactory in some
cases. The need for continuous reevaluation of the problem
of the ultimate disposition of such waste waters may become
even more pressing as a result of the goals stated in P.L.
92-500, the Federal Water Pollution Control Act Amendments
of 1972.
We will discuss trends in usage of industrial waste-
injection wells in the United States, the environmental
impacts of such wells, and methods for preventing ground
water pollution frcm such wells.
33
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Current Situation
An inventory of industrial waste-
-------
pharmaceutical companies, and about 25 percent by
refineries and natural gas plants. These data
identify the dominant present, and probable future,
industrial users of injection wells.
About 80 percent of the wells that have been
constructed are presently operating or will be put
into operation. Only 5 percent of wells that have
been constructed were initial failures and never
operated. Thus, the success ratio of such wells is
very high.
About 75 percent of existing wells are between 800
and 1800 meters deep. Less than 10 percent are
shallower than 300 meters. This fact provides some
assurance of protection to usable ground water
resources.
About 70 percent of present wells inject less than
15 liters per second (200 gpm) and 86 percent less
than 30 liters per second (400 gpm). This suggests
the rate that can be expected for most wells and
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reduces the need to consider waste-water streams
that exceed these amounts.
Oil-field-brine injection wells are discussed in a later
section.
36
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Alabama
California
Colorado
Florida
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Michigan
5
4
2
5
5
12
1
27
3
40
27
Nevada
New Mexico
New York
North Carolina
Ohio
Oklahoma
Pennsylvania
Texas
Tennessee
West Virginia
Wyoming
1
1
4
1
8
9
8
71
4
7
1
246
Table 1 Distribution of existing industrial
wastewater injection wells among the
22 states having such wells in 1972
(Warner, 1972) .
Industry Type
Refineries and natural gas
plants
Chemical, petrochemical &
pharmaceutical companies
Metal product companies
Other
Percent of Wells
1967
22
50
7
21
1972
26
56
7
11
Table 2 Distribution of injection wells by
industry type (Warner, 1972) .
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Initial failure (never operated)
Operation pending
Presently operating
Operation rare or suspended
Abandoned and plugged (after operating)
5%
13%
66%
11%
5%
Table 3 Operational status of industrial
injection wells (Warner, 1972) .
Total Well Depth
(meters)
0 - 300m
300 - 600
600 - 1,200
1,200 - 1,800
1,800 - 3,700
Over 3, 700
Percent of Wells
1967
7
29
22
31
9
2
1972
8
16
29
34
12
1
Table 4 Total depth of industrial injection
wells (Warner, 1972)
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Injection Rate
(liters per second)
0 - 3 Ips
3-6
6-13
13 - 25
25 - 50
Over 50
Percent of Wells
1967
27
17
25
26
4
1
1972
36
13
20
17
7
7
Table 5 Rate of injection in industrial
wells (Warner, 1972) .
Injection Pressure
(kilograms per square
centimeter )
Gravity flow
Gravity — 1 0 ksc
10 - 20
20 - 40
40 - 100
Over 100
Percent of Wells
1967
14
29
27
9
20
1
1972
27
22
14
16
18
3
Table 6 Pressure at which waste is injected
in industrial wells (Warner, 1972).
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Rock Type
Sand
Sandstone
Limestone and Dolomite
Other
Percent of Wells
1967
30
45
22
3
1972
36
25
35
4
Table 7 Type of rock used for injection by
industrial wells (Warner, 1972).
Quaternary 3%
Tertiary 33%
Mesozoic 6%
Permian — Mississippian 15%
Devonian — Silurian 15%
Ordovician — Cambrian 27%
57%
Precambrian 1 %
Table 8 Age of injection zone of industrial
wells (Warner, 1972) .
40
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• Only about 3 percent of existing wells are
injecting at well-head pressures exceeding 100
kg/cm2. This information, in conjunction with the
range of depths of wells previously mentioned, is
reassuring; it suggests that presently-operating
wells are generally using pressures compatible with
well depth and that waste waters are generally
being injected into naturally-occurring porosity,
rather than into continuously induced fractures.
Tables 7 and 8 can be interpreted to show the distribution
of wells by geologic provinces. The 36 percent of wells
injecting into poorly consolidated sands of Quaternary and
Tertiary age are principally located in the Gulf coastal
Plain. The 57 percent of wells injecting into consolidated
sandstones and limestones of Paleozoic age are located in
certain interior geologic provinces. Further examination of
other well characteristics shows that there is a good
correlation between the geologic province, depth,
construction method, and performance of existing wells,
which will permit emphasis on selected locations, aquifers,
and construction and operating requirements in a national
monitoring program.
41
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Environmental consequences
- -•--"" ' — - -~ '""•^"^••^•^Y"™"" l r LL i pi i| i« i ii
Tangible impacts of waste injection that can be predicted to
occur in every case are:
• Modification of the ground water system.
• Introduction into the subsurface of fluids with a
chemical composition different from that of the
natural fluids.
Tangible impacts that could occur in individual cases are:
• Degradation of ground water quality.
• Contamination of other subsurface resources, such
as petroleum, coal, or chemical brines.
• Stimulation of earthquakes,
• Chemical reaction between waste water and natural
water.
42
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• Chemical reaction between waste water and rocks in
the injection interval.
The degree to which any of these impacts can be predicted
and quantified in advance depends on the individual
situation. In the case of existing permitted wells,
significant adverse environmental effects should not occur.
Unfortunately some permitted wells are known to exist that:
• Do not have standby facilities.
• Have fractured the receiving rocks.
• Are injecting into fresh water aquifers.
• Have other deficiencies.
Contamination of Fresh Ground Water
The impact of greatest concern to most regulatory agencies
is the contamination of potable ground water. This could
occur where a well injects into a saline-water aquifer by:
• Escape of waste water through the well bore into an
aquifer containing usable water because of
insufficient casing or failure of the injection
43
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well casing due to corrosion, excessive injection
pressure, etc.
• Vertical escape of injected waste water, outside of
the well casing, from the injection zone into a
useable aquifer.
• Vertical escape of injected waste water from the
injection zone through confining beds that are
inadequate because of high primary permeability,
solution channels, joints, faults, or induced
fractures,
• Vertical escape of injected waste water from the
injection zone through nearby wells that are
improperly cemented or plugged, or that have
insufficient or leaky casing.
Direct contamination of fresh ground water could also occur
by lateral travel of injected waste water from a region of
saline water to a region of fresh water in the same aquifer.
44
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Indirect contamination of fresh ground water can also occur
when injected waste water displaces saline formation water,
causing it to flow into a fresh water aquifer. Vertical
flow of the saline water could be through paths of natural
or induced permeability in confining beds or through other
inadequately cased or plugged wells. If large volumes of
waste water were injected near a fresh-water/saline-water
interface, such as occurs in many coastal aquifers and
inland locations, the interface could be displaced with
saljlne water replacing fresh water in the zone of
displacement. Ferris (1972) discusses this response of
hydrologic systems to waste injection.
In many existing injection wells, the potential for direct
contamination of fresh ground water appears to be small
because of the construction used in these wells and because
of the large vertical distance between the injection zones
arid fresh water aquifers. The belief that the potential for
direct aquifer contamination is small, based on the few
instances of direct contamination that have been documented,
is suspect however and ground water quality near such wells
should be monitored carefully. The vertical or lateral
movement of saline water into fresh water aquifers as a
45
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result of increased formation pressures can be expected to
occur.
Contamination of Other Subsurface Resources
No instance of contamination of other subsurface resources
by injected industrial waste water has yet been reported.
The fact that little evidence of degradation of potable
ground water and other resources by this type of injected
waste water has been found may be due to the limited amount
of monitoring being done and should not be cause for
relaxation of vigilance in regulating and operating such
wells. On the contrary, as more wells are constructed each
year, regulation and operation must be increasingly more
sophisticated to maintain this record.
Chemical reaction between waste water and formation minerals
and water is a possible problem in well operations, but does
not present much potential for environmental impact that
would be of concern to the public.
Earthquake Stimulation
The exact geologic and hydrologic circumstances in which
earthquakes can be stimulated by waste-water injection are
46
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not yet known. The general requirement is the presence of a
fault system along which movement can be induced in an area
where earth strains are present that can be relieved by such
movement. It is believed that fluid injection can act as a
trigger for release of such strain energy, thus causing
earthquakes. A survey of presently existing industrial
injection wells ether than those injecting oil-field brine
has shown that very few are present in such locations, and
none, besides the Rocky Mountain Arsenal well near Denver,
has yet been related to earthquake occurrence.
Control Methods
The following list describes processes, procedures, and
methods for control of industrial waste water injection into
aquifers. Control is based on proper siting, design,
construction, operation, abandonment, and monitoring as
briefly discussed in subsequent subsections.
• Evaluation of hydrogeologic framework and
restriction on unsuitable locations and aquifers
for waste water injection.
47
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Evaluation of fluids for injection including
estimation of nature and extent of chemical
reactions between injected fluids and aquifer
fluids and minerals, of heat generation and its
effects in the case of radioactive wastes and
restrictions on those deemed unsuitable.
i
Requirement of proper design and construction of
injection wells including hardware and sealants.
Requirement of thorough hydrogeologic evaluation
during construction and testing of wells.
Determination of aquifer characteristics and
estimation of aquifer response to injection, and
direction and rate of movement of injected fluid
and aquifer fluids.
Restriction on operating programs for injection
wells.
Surface equipment and programs for emergency
procedures in the event of malfunction, including
48
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rapid shutoff and standby facilities and programs
for long-term decontamination.
• Abandonment procedures for all wells.
• Monitoring programs for injection wells.
• Monitoring programs for aquifers.
49
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EXTENSIVb AREAS WHERE RELATIVELY
IMPERMEABLE IGNEOUS-INTRUSIVE AND
METAMORPHIC ROCKS ARE EXPOSED AT SURFACE
EXTENSIVE AREAS WHERE V01CANIC SEQUENCES
ARE EXPOSED AT SURFACE
_— BOUNDARIES OF GEOLOGIC FEATURES
DfcNVER \ APPROXIMATE BASIN OUTUNF.S
INDUSTRIAL-WASTE INJECTION SYSTEMS
(FEBRUARY, 1966)
GEOLOGIC DETAIL NOT SHOWN
Figure A Geologic features significant in deep waste-
injection well-site evaluation, and locations
of industrial-waste injection systems (Warner,
1968) .
50
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Local Site Evaluation
An outline of the factors for consideration in the
evaluation of injection-well sites is given in Table 9.
Experience has shown that nearly all types of rocks can,
under favorable circumstances, have sufficient porosity and
permeability to yield or accept large quantities of fluids.
Sedimentary rocks, especially those deposited in a marine
environment, are most likely to have the geologic
characteristics suitable for waste-injection wells. These
characteristics are: (1) an injection zone with sufficient
permeability, porosity, thickness, and areal extent to act
as a liquid-storage reservoir at safe injection pressures;
and (2) an injection zone that is vertically below the level
of fresh water circulation and is confined vertically by
rocks that are, for practical purposes, impermeable to waste
liquids.
51
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Regional Geologic and Hydrologic Framework
Structural geology
Stratigraphic geology
Groundwater geology
Mineral resources
Seismicity
Hydrodynamics
Local Geology and Geohydrology
• Structural geology
• Geologic description of sedimentary rock units
1. Lithology
2. Detailed description of potential injection horizons and
confining beds
a. Thickness and vertical and lateral distribution
b. Porosity (type and distribution as well as amount)
c. Permeability (same as b)
d. Chemical characteristics of reservoir fluids
3. Groundwater aquifers at the site and in the vicinity
a. Thickness
b. General character
c. Amount of use and potential for use
4. Mineral resources and their occurrence at the well site
and in the immediate area
a. Oil and gas (including past, present and possible
future development)
b. Coal (as in a)
c. Brines (as in a)
d. Other (as in a)
Table 9 Factors for consideration in the
geologic and hydrologic evaluation of a
sit.e for deep well industrial waste
injection.
52
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Vertical confinement of injected wastes is important not
only for the protection of usable water resources, but also
for the protection of developed and undeveloped deposits of
hydrocarbons and other minerals. The effect of lateral
movement of waste on such natural resources also must be
considered.
Unfractured beds of shale, clay, slate, anhydrite, gypsum,
marl, and bentonite have been found to provide good seals
against the upward flow of fluids. Limestone and dolomite
may be satisfactory confining strata but these rocks
commonly contain fractures or solution channels and their
adequacy must be determined carefully in each case.
The minimum salinity of natural water in the injection zone
probably will be specified by regulatory agencies in most
states, but will be at least 1,000 mg of dissolved solids
per liter of water except under unusual circumstances.
Water containing less than 500 mg/1 is considered to be
acceptable for pctable water used by interstate carriers.
Formerly, if such water was not available, water containing
53
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1,000 mg/1 of dissolved solids was considered acceptable.
The minimum salinity in arid regions may be set at a level
higher than 30,000 mg/1 of dissolved solids to provide a
margin of safety and because water with this dissolved-
solids content is used in certain areas to supply
desalination plants which produce fresh water.
Illinois agencies have determined that ground water with a
dissolved solids content less than 10,000 mg/1 should be
protected. All ground waters in New York have been
classified, based on quality. According to the New York
classification, waste injection is prohibited in aquifers
containing water with a dissolved solids content of 2,000
mg/1 or less.
It has been found that a confining stratum only a meter
thick may provide a good seal to retain oil and gas. Such
thin confining beds generally would not be satisfactory for
containing injected waste because they would be very
susceptible to hydraulic fracturing, and even a small fault
could completely offset them vertically. Fortunately, in
many places hundreds or thousands of feet of impermeable
54
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strata enclose potential injection zones and virtually
ensure their segregation.
In addition to stratigraphy, structure, and rock properties,
which are factors routinely considered in subsurface
studies, aquifer hydrodynamics may be significant in the
evaluation of waste-injection well sites. The presence of a
natural hydrodynamic gradient in the injection zone will
cause the injected waste to be distributed asymmetrically
about the well bcre and transported through the aquifer even
after injection has ceased.
Hydrodynamic dispersion (the mixing of displacing and
displaced fluids during movement through porous media) may
cause much wider distribution of waste in the injection zone
than otherwise wculd be anticipated. Dispersion is known to
occur in essentially homogeneous isotropic sandstone, and it
could lead to particularly rapid lateral distribution of
waste in heterogeneous sandstone and fractured or cavernous
strata. Sorption of waste constituents by aquifer minerals
retards the spread of waste from the injection site.
55
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Mathematical models now available are satisfactory for
accurately predicting the movement of waste in most natural
aquifers only under restricted, simplified physical
circumstances. Even if knowledge of the physics of fluid
movement- in natural aquifers were considerably more
advanced, the determination of the physical parameters that
characterized an injection zone would still be a problem if
few subsurface data were available. These restrictions do
not, however, preclude the quantitative estimation of the
rate and direction of movement of injected waste.
The maximum pressure at which liquids can be injected
without causing hydraulic fracturing may be the factor
limiting the discharge rate and operating life of an
injection well. The injection pressure at which hydraulic
fracturing will occur is related directly to the magnitude
of regional rock stress and the natural strength of the
injection zone (Hubbert and Willis, 1957). In some areas,
the pressure at which hydraulic fracturing will occur can be
estimated before drilling on the basis of experience in
nearby oil fields.
56
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Other considerations in the determination of site
suitability are: (1) the presence of abnormally high natural
fluid pressure and temperature in the potential injection
zone that may make injection difficult or uneconomical; (2)
the local incidence of earthquakes that can cause movement
along faults and damage to the subsurface well facilities;
(3) the presence in the area of other wells, or, improperly
plugged wells that penetrate the injection zone and provide
a means for escape of injected waste to ground water
aquifers or to the surface; (4) the mineralogy of the
injection zone and chemistry of the resident water, which
may determine the injectability of a specific waste; and (5)
the possibility that in tectonically unstable areas, fluid
injection may contribute to the occurrence of earthquakes.
Waste Evaluation
A foremost consideration in evaluating the feasibility of
waste injection is the character of the waste. Table 10
lists some pertinent factors.
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The suitability of waste for subsurface injection depends on
its volume and physical and chemical properties of the
potential injection zones and their interstitial fluids.
• Volume
• Physical Characteristics
1. Specific gravity
2. Temperature
3. Suspended solids content
4. Gas content
• Chemical Characteristics
1. Chemical constituents
2. pH
3. Chemical stability
4. Reactivity
a. with system components
b. with formation waters
c. with formation minerals
5. Toxicity
• Biological Characteristics
Table 10 Factors to be considered in evaluating
the suitability of untreated industrial
wastes for well injection.
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Waste disposal intc subsurface aquifers ordinarily
constitutes the use of limited storage space, and only
concentrated, very objectionable, relatively untreatable
waste should be considered for injection. The fluids
injected into deep aquifers do not occupy empty pores; each
liter of waste will displace or compress a liter of the
fluid which saturates the aquifer. Optimal use of
underground storage space will be realized by use of well
injection only where (1) more satisfactory alternative
methods of waste treatment and disposal are not available,
and (2) minimization of injected-waste volumes is achieved
through good waste management.
Knowledge of the mineralogy of the aquifer and the chemistry
of interstitial fluids and waste should indicate the
reactions to be anticipated during injection. Laboratory
tests can be performed with rock cores and formation and
waste water samples to confirm anticipated reactions.
Selm and Hulse (1959) lists the reactions between injected
and interstitial fluids that can cause the formation of
plugging precipitates—(1) precipitation of alkaline earth
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metals such as calcium, barium, strontium, and magnesium as
relatively insoluble carbonates, sulfates, orthophosphates,
fluorides and hydroxides; (2) precipitation of metals such
as iron, aluminum, cadmium, zinc, manganese, and chromium as
insoluble carbonates, bicarbonates, hydroxides,
orthophosphates, and sulfides; and (3) precipitation of
oxidation-reduction reaction products.
Common minerals that react significantly with wastes are the
acid soluble carbonate minerals and the clay minerals.
Acidizing of reservoirs containing carbonate minerals is an
effective well-stimulation technique, and reaction of acidic
wastes with carbonate minerals thus might be expected to be
beneficial. An undesirable effect of the reaction of acid
waste with carbonate minerals could be evolution of CCU
that might increase pressure and cause plugging if present
in excess of its solubility. Roedder (1959) reported that
the reaction of acid aluminum nitrate waste with calcium
carbonate results in a gelatinous precipitate that could
cause plugging.
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Clay minerals are known to reduce the permeability of
sandstone to water in comparison to its permeability to air.
The permeability of a clay-bearing sandstone to water
decreases with decreasing water salinity, decreasing the
valence of the cations in solution, and increasing the pH of
the water.
Ostroff (1965) and Earner (1965, 1966) give additional
references and discussion concerning waste injectability.
Factors that bear on waste injectability, such as aquifer
mineralogy, temperature and pressure, and chemical quality
of aquifer fluids, are a logical part of feasibility reports
because the treatment necessary to make a waste injectable
can be an important part of a total waste management
program.
Well Construction and^Evaluation
The variability cf geologic situations and the
characteristics of wastes precludes establishment of rigid
specifications for injection-well construction. Each
injection system requires individual consideration with
respect to 'waste volume and type, and the geologic and
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hydrologic conditions that exist. Certain general
requirements, however, can be outlined.
Construction of well facilities for an injection system
includes drilling, logging and testing, and completion
activities. A hcle must first be drilled, logged, and
tested before it can be ascertained that it should be
completed as an injection well. The completion phase
includes installation and cementing of the casing,
installation of injection tubing, and other related
procedures such as perforating or slotting the casing and
stimulating the injection horizon.
Drilling programs should be designed to permit installation
of the necessary casing strings with sufficient space around
the casing for an adequate amount of cement. Samples of the
rock formations penetrated should be obtained during
drilling. It may be necessary to have formation cores or
water samples at horizons of particular importance to
provide necessary geologic and hydrologic data. Logging and
testing data should be filed with the appropriate state
agency or agencies.
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Table 11 summarizes the type of information desired in
subsurface evaluation of the disposal horizon and the
methods for obtaining this information.
Design of a casing program depends primarily on well depth,
character of the reck sequence, fluid pressures, type of
well completion, and the corrosiveness of the fluids that
will contact the casing. Where fresh ground water supplies
are present, a casing string (surface casing) is usually
installed to below the depth of the deepest ground water
aguifer immediately after drilling through the aquifer
(Figure B). One or more smaller-diameter casing strings are
then set, with the bottom of the last string just above,
into or through the injection horizon, depending on whether
the well is to be completed as an open hole or is to be
cased and perforated.
The annulus between the hole wall and the casing is filled
with cement to protect the casing from external corrosion,
to increase casing strength, to prevent mixing of the waters
contained in the aquifers behind the casing, and to
forestall travel of the injected waste into aquifers other
than the disposal horizon. Neat Portland cement (no sand or
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gravel) is the basic material for cementing. Many additives
have been developed to impart some particular quality to the
cement. Additives can, for example, be selected to give
increased resistance to acid, sulfates, pressure,
temperature and shrinkage.
Information Desired
Porosity
Permeability
Fluid pressures in formations
Water samples
Geologic formations intersected
by hole
Thickness and character of
disposal horizon
Mineral content of formation
Temperature of formation
Amount of flow into various
horizons
Methods Available
for Evaluation
Cores, electric logs, radio-
active logs, sonic logs
Cores, pumping or injection
tests, electric logs
Drill stem tests, water level
measurements
Cores, drill stem tests
Drill time logs, drilling samples,
cores, electric logs,
radioactive logs, caliper logs
Same as above
Drilling samples, cores
Temperature log
Injectivity profile
Table 11 Summary of information desired in
subsurface evaluation of disposal
horizon and methods available for
evaluation.
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Temperature logs, cement logs, and other well-logging
techniques can be required as a verification of the adequacy
of the cementing. Cement can be pressure-tested if the
adequacy of a seal is in question.
Waste should be injected through separate interior tubing
rather than being in contact with the well casing. This is
particularly important when corrosive wastes are being
injected. The injection tubing can be made from, or lined
with, a material that is not affected by the particular
waste involved. A packer can be set near the bottom of the
tubing to prevent corrosive waste from contacting the
casing. Additional corrosion protection can be provided by
filling the annular space between the casing and the tubing
with oil or water containing an added corrosion inhibitor.
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Tubing Pressure Gauge
Fresh-Water-Bearing
Surface Sands And
Gravels
Impermeable Shale
Confined Fresh-Water
Bearing Sandstone
Impermeable
Shale
#
O1 • . 0 ' •
-^ *.'••>.'•••
oXvv*.
~ ~ -
•'•'•.': -• •'.-' •'•'.'
*• ~-_-' T— ._~"
^
1
^
1
^
X \
^
/^
'S
/ V
^
i s
0 \
<&
Annulus Pressure Gauge
Permeable Salt-Water
Bearing Sandstone
Injection Horizon
-; •',- Surface Casing Seated In
~Z. Impermeable Formation
Below Fresh Water And
Cemented To Surface
Inner Casing Seated In
Injection Horizon
And Cemented To Surface
Injection Tubing
: Annulus Filled With
, Noncorrosive Fluid
- ^ Packers To Prevent Fluid
Circulation In Annulus
' . Open-Hole Completion
Impermeable Shale
Figure B Schematic diagram of an industrial waste
injection well completed in sandstone
(modified after Warner, 1965).
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It is frequently desired to increase the acceptance rate of
injection wells by chemical or mechanical treatment of the
injection zone. Careful attention should be given to
stimulation techniques such as hydraulic fracturing,
perforating, and acidizing to insure that only the desired
intervals are treated and that no damage to the casing,
cement, or confining beds occurs.
Aquifer Response and Wastewater Movement
Estimates of the rate of pressure build-up in the injection
zone are important because the maximum pressure at which
liquids can be injected may be the factor limiting the safe
injection rate and operating life of an injection well.
Excessive pressure may cause the rupturing of the injection
formation and the movement of the waste to fresh water
aquifers.
From data obtained during construction and testing of an
injection well, estimates can be made of the rate of
increase of pressure in the receiving aquifer for a
projected rate of waste water injection. Van Everdingen
(1968) outlines the methodology for estimating the pressure
build-up resulting from injection wells.
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Estimates of the lateral extent of waste water movement are
needed so that the location of the underground space
occupied by the waste water can be made a matter of record
to be used in regulation and management of the subsurface.
Estimates of the extent and direction of waste water
movement can be made after the hydrogeologic characteristics
of the receiving aquifer have been determined. This
estimate is potentially very complex, since the cylindrical
pattern that can be assumed as the most elementary case may
be modified by the natural flow system in the aquifer,
hydrodynamic dispersion, differential permeability in the
injection zone and density and viscosity differences between
injected and interstitial fluids.
Operating Program
The operating program for an injection system should conform
with the geological and engineering properties of the
injection horizon and the volume and chemistry of the waste
fluids.
Injection rates and pressures must be considered jointly,
since the pressure will usually depend on the volume being
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injected. Pressures are limited to those values that will
prevent damage to well facilities or to the confining
formations. The maximum bottom-hole injection pressure is
commonly specified on the basis of well depth. Regulatory
agencies have specified maximum allowable bottom-hole
pressure of from about 0.11 to 0.23 kilograms per square
centimeter per meter of well depth, depending on geologic
conditions, but operating pressures are seldom allowed to
exceed about 0.18 ksc per meter of depth.
Experience with injection systems has shown that an
operating schedule involving rapid or extreme variations in
injection rates, pressures, or waste quality can damage the
facilities. Consequently, provisions should be made for
shut-off in the event of hazardous flow rates, pressure, or
waste quality fluctuations.
Surface Equipment and Emergency Procedures
Surface equipment includes holding tanks and flow lines,
filters, other treatment equipment, pumps, monitoring
devices, and standby facilities.
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Surface equipment associated with an injection well should
be compatible with the waste volume and physical and
chemical properties to insure that the system will operate
as efficiently and continuously as possible. Experience
with injection systems has revealed the difficulties that
may be encountered due to improperly selected filtration
equipment and corrosion of injection pumps.
Surface equipment should include well-head pressure and
volume monitoring equipment, preferably of the continuous
recording type. Where injection tubing is used, it is
advantageous to monitor the pressure of both the fluid in
the tubing and in the annulus between the tubing and the
casing. An automatic alarm system should signal the failure
of any important component of the injection system. Filters
should be equipped to indicate immediately the production of
an effluent with too great an amount of suspended solids.
Standby facilities are essential in order to cope with
malfunctions of a well that might occur. In all cases,
provision should be made for alternative waste management
facilities and procedures in the event of injection system
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failure. Alternative facilities could be standby wells or
holding tanks.
In situations where the character of the waste water being
injected would dictate the need, additional facilities and
procedures could be available for use in the event of
engineering failures of the system or detection of
contamination of a subsurface resource. For example,
handling of a particularly corrosive waste water would be
reason for planning in advance the procedure to be used in
the event that tubing failure during operation was detected.
Such a procedure might be to begin immediately injection of
a non-*corrosive liquid into the well until the well bore was
completely cleared, then to shut the well in until the
reservoir pressure had declined to a level that would allow
removel of the damaged tubing without backflow of the
corrosive waste water. Such a procedure would help to
minimize damage to the casing, packer, etc. Injection of a
radioactive waste water would require establishment of
procedures for use during well workovers or any other
handling of equipment that might become contaminated.
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Emergency procedures could also include notification of
nearby users of ground water or other resources, should
contamination be detected, or even a program for aquifer
rehabilitation.
Monitoring Procedures
Monitoring can be performed on the injection system itself,
in the injection zcne, or in aquifers above or below the
injection zone.
Well-head pressure and waste injection rate should be
continuously measured. If injection tubing is used, the
casing-tubing annulus should be pressure monitored. Other
types of monitoring include measurement of the physical,
chemical, and biological character of injected fluids on a
periodic or continuous basis, and periodic checking of the
casing and tubing for corrosion, scaling, or other defects.
The possible purposes in monitoring the injection zone or
adjacent aquifers are to determine fluid pressures and the
rate and direction of movement of the waste water and
aquifer fluids.
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As discussed by Viarner (1965) , monitoring with wells to
determine the rate and extent of movement of waste water
within the injection zone may be of limited value because of
the difficulty of intercepting the waste water front and of
interpreting information that is obtained. For these
reasons, and because of the cost, few such monitor wells
have been constructed.
A more feasible approach is to monitor the fluid pressure in
the injection zone or adjacent aquifers. A larger number of
monitor wells have been constructed for this purpose.
Goolsby (1971) discusses an example of an injection system
where a monitor well was useful for both detection of waste
travel and measurement of reservoir fluid pressure.
The most common type of monitor well used in conjunction
with waste water injection systems is that constructed in
the fresh water aquifers near the injection well. If these
wells are pumping wells, they provide a means for detecting
(eventually) leakage from the injection well or injection
horizon; pollutants entering the supply aquifer will tend to
move toward a discharging well. Changes in the quality of
water in springs, water supply wells, streams and lakes may
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also be monitored to detect effects from waste disposal
wells.
Sta te_Programs
The status of regulation of disposal wells at the state
level is highly variable. Most states that have significant
oil production regulate the disposal of oil field brine
through an oil and gas agency, but other categories of
disposal wells are most frequently regulated through water
pollution control, environmental protection, or health
agencies.
/
A few states have developed specific laws, regulations, or
policies concerning industrial waste water injection. A
chronological list of these developments is given below:
1961 Texas - Injection well law adopted
1966 Kansas - Regulations adopted
1967 Ohio - Injection well law adopted
New York - Ground water classified
1969 Indiana - "Test Hole" Legislation enacted
Michigan - "Mineral Well Law" enacted
New York - Injection well policy established
Ohio Valley - Regulatory policy recommended
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Texas - 1961 law amended
West Virginia - Injection well legislation
enacted
1970 Illinois - Policy specified
FWPCA - Policy announced
Colorado - Rules and regulations for
subsurface disposal adopted
1971 Missouri - Disposal wells prohibited
1972 Oklahoma - Regulations adopted
Council of State Governments - Model
State Toxic Waste Disposal Act
1973 EPA - Policy announced.
Texas was the first state to pass a law specifically
concerning industrial, waste water injection wells, in 1961.
Since that time, several other states have passed similar
laws or amended existing ones to include consideration of
underground injection. Formal regulations have been adopted
by Colorado and Oklahoma. Formal or informal policy
guidelines have fceen specified by several states. with the
exception of the specific cases listed above, most states
regulate injection wells under general water pollution
control laws, oil and gas laws, or both. There is
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frequently overlapping jurisdiction among state agencies
regarding such wells.
Because regulation of industrial waste water injection wells
is a relatively new responsibility, the laws, regulations,
and policies in this area are in the developmental stage.
During 1970-1972, an advisory committee to the Ohio River
Valley Water Sanitation Commission (ORSANCO) formulated
policies, procedures, and technical criteria for use by the
eight member states (Illinois, Indiana, Kentucky, New York
Ohio, Pennsylvania, Virginia, and West Virginia). In
January 1973, ORSANCO formally adopted the committee
recommendations as Resolution 1-73, incorporating eight
steps:
1. Preliminary assessment by the applicant of the
geology and hydrogeology at the proposed well site
and the suitability of the waste water for
injection. These initial studies should be made in
consultation with the appropriate state agencies.
2. Application to the state agency with legal
jurisdiction for permission to drill and test a
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well for subsurface waste water injection. The
application must be supported by a report that
documents all details of the proposed injection
system, including monitoring and emergency standby
facilities. On issuance of a permit, the applicant
will be apprised of the geologic and geohydrologic
parameters that will be employed by the state in
reaching its final determination on feasibility of
waste water injection into the well, anticipated
limitations on injection pressure and injected
volumes, the probable monitoring requirements, and
probable requirements for alternative waste water
management programs in the event that operational
problems occur during the use of the injection
well.
3. Drilling and evaluation of the well and submission
of samples, logs, test information, and a well-
completion report to the state.
4. Request by the applicant for approval to inject
waste water into the well. The request should
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indicate any changes from the original plan in
system construction and operating program.
5. Prompt evaluation, by the State, of the well and
approval, approval-witb-modification, or
disapproval of the proposed injection system based
on the geologic, geohydrologic, and engineering
data submitted. On approval, the applicant will be
provided with specific instructions and monitoring
requirements.
6. Operation of the injection system in accordance
with State requirements. The appropriate
regulatory agency should be notified immediately if
operational problems occur, if remedial work is
required, or if significant changes in the waste
water stream are anticipated.
7. Abandonment of the well in accordance with state
regulations or other technically acceptable
procedures.
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8. In addition to the seven steps listed above, where
a proposed injection well is to be located within
five miles of the state border, the appropriate
agencies in the adjacent state should be provided
the opportunity to review and comment on the
application. Further, these agencies should be
advised of any significant problems that occur
during the operation of such a well.
These procedures are supplemented by forms, outlines, and
technical criteria to be used in implementation. It is
anticipated that the individual states will formally or
informally adopt the procedures and supplementary material,
with such modifications as each may wish to make to meet
state organizational and administrative needs. It is
intended that the recommendations will be updated and
modified as experience shows it to be necessary.
An example of the application of ORSANCO Resolution l-*73 to
a particular state is provided by Warner (1972) in a report
to the Illinois Institute for Environmental Quality.
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OTHER WELLS
In addition to the types of industrial waste water injection
wells discussed above, other classes of wells are possible
sources of ground water contamination. Such wells include
those used in conjunction with oil exploration and
production, solution mining, geothermal energy production,
sewage treatment, desalination, radioactive waste disposal,
underground gas storage and water exploration and
production.
Many of the technical and regulatory aspects that have
previously been described apply to these wells. The
differences that exist will be discussed.
Petroleum Industry Wells
Wells are used by the petroleum industry for exploration,
for production of cil and gas, and for injection of brines
brought to the surface during oil production. The purpose
of brine injection may be to maintain reservoir pressure, to
provide a displacing agent in secondary recovery of oil, or
to dispose of the brine.
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The total number of petroleum exploration and production
wells that have been drilled in the United States since the
first oil well was constructed in 1859 is unknown, but the
number exceeds 2,300,000. Iglehart (1972) reported, in the
American Associaticn of Petroleum Geologists i&th. An.n_uai
B§port on DrilljLng Activity in the United States, that
27,300 wells were drilled in 1971, a year in which drilling
activity was at a low level. The number of existing brine
injection wells is not documented either, but inquiry among
the oil producing states indicated that in 1965 about 20,000
such wells existed in Texas alone (Warner, 1965}, with
probably an equal number distributed among all other states.
Information gathered by the Interstate Oil Compact
Commission (1964) shows that about 1.4 billion metric tons
of water were produced in 1963 in conjunction with
petroleum. At that time, about 72 percent of the produced
water was reinjected. The relative percent being reinjected
today is undoubtedly higher as other means of disposal, such
as in unlined pits, have since been outlawed in Texas and
other states.
Hazard to usable ground water may result from any well,
including petroleum production wells, that is inadequately
-------
cased, cemented, or plugged. Such wells provide avenues for
interaquifer movement of saline ground water and other
fluids. A particular danger to usable ground water is posed
by the hundreds of thousands of oil and gas wells that were
drilled in the late 1800's and early 1900's and abandoned
with inadequate plugging. Examples of ground water
contamination caused by abandoned, improperly-plugged oil
and gas wells could probably be found in most petroleum-
producing states. Fryberger (1972), Wilmoth (1971), and
Thompson (1972) discuss cases from Arkansas, West Virginia,
and Pennsylvania, respectively.
The mechanism of possible ground water contamination from
oil field brine injection wells is essentially the same as
was discussed for other industrial waste water injection
wells. Since oil field brine is a natural water and does
not usually contain chemicals that are extremely toxic in
small quantities, it may be of less concern as a pollutant
from a public health standpoint than some other industrial
waste waters. However, the very high levels of dissolved
solids that are found in many cases, and the volumes
involved, present the potential for degradation of very
large amounts of usable ground water if brine injection is
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not properly managed (Ostroff, 1965). It is commonly
believed that most brine is returned to the same geologic
formation from which it was removed. The relative amount
returned to the same formation as compared with that
injected into other horizons is not known, but substantial
amounts are injected into aquifers that have not been
depressured by petroleum production. A particular example
of this is injection of oil field brines into the Glorieta
Sandstone in the Oklahoma Panhandle and adjacent areas
(Irwin and Morton, 1969). The hazard from this practice is
from interaquifer flow of brine, or alternation of the
position of the fresh-water saline-water interface.
The procedures and methods for control and regulation of
brine injection are essentially the same as discussed for
industrial waste water injection. Locating and plugging
abandoned oil and gas wells may be difficult and expensive.
Pasini and others (1972) discuss the technology and cost of
plugging abandoned wells in the Appalachian area. The cost
ranged from $8,600 to $14,000 each for the four wells
plugged in that study. The average cost for plugging 60
abandoned wells in The Hubbard Creek Reservoir Watershed
during the period 1963-1965 was $1500 each.
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A detailed investigation of the problems presented by one
incident of pollution of a fresh water aquifer by an oil
field brine was made by Fryberger (1972). The present
extent of the brine pollution is 2.6 square kilometers (one
square mile); however, it will spread to affect 11.7 sq. km
(4-1/2 square miles) and may persist for more than 250 years
before being flushed from the aquifer if indeed it were ever
completely removed. Several methods for rehabilitating the
aquifer were examined; costs ranged from $80,000 to
$7,000,000 and no method is economically justified at the
present time.
Wells Used in Sglution Mining
For many years wells have been used to extract sulfur, salt
and other minerals from the subsurface by injection of water
and extraction of the minerals in solution. In many cases
the residual brine from such operations is disposed of
through injection wells. A similar type operation, widely
practiced in areas where salt deposits exist, is the
construction of solution caverns for storage of liquid
petroleum gas. In this procedure water is injected into the
salt beds and a caveru developed as the salt is dissolved
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and the brine pumped out. The extracted brine is then
disposed of by injection into a suitable aquifer.
A relatively new practice is the in situ mining of metals,
particularly copper, by the injection (through wells) of
acid into an ore body or a tailings pile, and the extraction
of the solution containing the metal through pumping wells
or as seepage. In at least one case, a deep injection well
is planned for disposal of the spent acid solution, after
the metals have been removed.
The potential problems of ground water pollution from the
solution mining cf soluble minerals, and the techniques for
prevention of such pollution, are similar to those described
previously. Solution mining of metallic minerals presents a
different problem in that the mining will, in most cases, be
in geologic strata containing usable water. The mining
itself may need to be carefully managed to avoid ground
water contamination. Disposal of the spent acid solutions
by injection would be similar to other industrial waste
water injection.
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McKinney (1973) and Pernichele (1973) discuss current trends
in solution mining and mining geohydrology and list a number
of recent references.
mJ;-'- Energy. feell§
The Geothermal Steam Act of 1970 (Public Law 91-581)
provides an important impetus to the further development of
geothermal energy sources. In the United States, about 0.73
million hectares (1.8 million acres) are designated as known
geothermal resource areas and an additional 38.7 million
hectares (95.7 million acres) have prospective value (USGS,
1971) . Of the known areas, 90 percent lie in the thirteen
western states and Alaska. Geothermal reservoirs may
contain either dry steam or hot brines, with the latter
predominating. Both condensed steam and cooled brines
commonly are reinjected through wells into the geothermal
structure (US. Department of the Interior, 1971) .
At present, the two most significant geothermal areas in the
United States are The Geysers and Imperial Valley, both in
California.
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A substantial amount of electrical energy already is
generated from dry steam produced at The Geysers. A three-
fold increase in capacity is planned by 1975. Injection
wells are used to return condensate to the reservoir.
Because of oxygen content, the condensate is reported to be
corrosive, necessitating the use of special materials
(Chasteen, 1972) .
The United States Eureau of Reclamation and others have
proposed major developments of geothermal energy from the
hot brine reservoirs underlying the Imperial Valley. The
Bureau of Reclamation concept contemplates production of
0.31 million hectare-meters (2.5 million acre-feet) of fresh
water per year. The 0.37 to 0.49 million hectare-meters (3
to 4 million acre-feet) of brines withdrawn would be
replaced by water from the Pacific Ocean, the Salton Sea, or
other sources. Replacement water would be injected through
approximately 100 wells on the periphery of the qeothermal
field, to maintain reservoir pressures and preclude land
subsidence and lowering of the overlying fresh water table
(Bureau of Reclamation, 1972). The high pressures and
temperatures and the corrosiveness of the injected fluid are
a particular problem in such injection wells; plugging a
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well if subsurface casing damage occurs could be difficult
or even impossible.
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Wglls_for Injection of Sewage Effluent and Desalination
Plant Brines
A few wells have been constructed in Florida, Hawaii,
Louisiana, and Texas for injection of treated sewage
effluent into salt water aquifers. It has also been
proposed to inject brines from advanced waste treatment
plants using desalination techniques, and from plants
constructed to produce usable water by desalination methods.
The technology of injecting such waters is similar to that
previously discussed. The particular problem with this
category of waste waters is the very large volume that may
be produced. In general the disposal of sewage effluent by
injection into saline aquifers probably is questionable for
at least two reasons: The effluent is of too high a quality
to waste, and the amount that can be safely injected is too
small to be significant in solving the overall problem of
managing such wastes. Under certain conditions a double
benefit can be realized by injecting a good quality sewage
effluent so as to displace a poor quality ground water, thus
creating a reserve of usable water in underground storage.
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Injection of brines from desalination plants may be the most
desirable method of disposing of these wastes in cases where
the geology is suitable and the volumes of waste are not too
large (Dow Chemical Company, 1972).
Radioactive Waste_Disposal Wells
The possible use of injection wells for disposal of
radioactive wastes has been the subject of extensive
investigation since the early 1950's. To date, at least
three wells have been constructed for injection of liquid
radioactive waste waters into deep aquifers, but the only
one that has been used for this purpose is located at a
uranium mill at Grants, New Mexico (Arlin, 1962). In spite
of the limited use of injection wells in the past, they may
be the most desirable means of handling some radioactive
liquids today and perhaps others in the future (de Laguna,
1968; Belter, 1972).
Particular problems related to injection of liquid
radioactive waste are the possible extreme toxicity of the
waste and the heat generated by radioactive decay.
90
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A second method of radioactive waste disposal through wells
is injection of radioactive wastes incorporated in cement
slurries into hydraulic fractures induced in thick shale
beds. This method of disposal has been used for
intermediate level wastes at the Oak Ridge National
Laboratory since 1966 and is being tested at the Nuclear
Fuel services Chemical Processing Plant site in West Valley,
New York (Belter, 1972) . A discussion of the environmental
aspects of this disposal method is provided by de Laguna and
others (1971) .
Gas Storage Wei1s
Underground gas storage may be defined as storage in rock of
synthetic gas or of natural gas not native to the location.
Storage can be in depleted oil or gas reservoirs, in
aquifers, in mined caverns, or in dissolved salt caverns.
Gas may be stored in gaseous or liquid form.
The largest quantities of gas are stored in the gaseous form
in depleted oil or gas reservoirs or in aquifers. In 1971
there were 333 underground gas storage fields in 26 states.
About 60 percent of the storage capacity was located in
Illinois, Pennsylvania, Michigan, Ohio, and West Virginia.
91
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The number of wells per field ranges from less than 10 to
more that 100, depending on the size of the structure in
which the gas is being stored (American Gas Association,
1967 and 1971).
Underground gas storage fields present a potential for
contamination of usable ground water by leakage of gas
through the confining beds, through abandoned improperly
plugged wells, or through inadequately constructed gas
injection or withdrawal wells. Gas could also escape from
an overpressured field and migrate laterally in the storage
aquifer, which in some cases contains usable water. A case
history of a leaky storage field in Illinois was documented
by Hallden (1961). In that instance, it was not possible to
conclusively determine whether the leakage was from faulty
well cementing, lack of an adequate confining bed, faulting
of the confining bed, or unplugged abandoned wells. Some
leakage from storage fields is common, but since the gas is
a valuable commodity, operating companies have a strong
interest in minimizing such losses. Storage fields are
subject to state or federal licensing and regulation so the
engineering characteristics of a field must be carefully
92
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determined prior to licensing, and the fields must be
monitored during operation.
Water Wells
The mere existence of any type of well so poorly construcrx-ri
that surface materials can fall or run down the hole is a
ground water pollution hazard. Due to the technology
employed, most injection wells and oil wells are not so
poorly constructed. The main offenders are water wells,
some of which permit the introduction, directly into
aquifers, of dead skunks and the like, and many of which
provide a path fcr polluted surface water and septic tank
effluent to drain directly into the aquifers from which
drinking waters is drawn, at a point very near the intake.
This obvious hazard has an obvious solution in the excerise
of reasonable care, by competent well drillers, in well
construction. An impermeable material (preferably neat
cement) should be emplaced around the surface casing, from
top to bottom, to prevent downward movement of pollutants.
Specific water well pollution problems result from:
93
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• Gravel packed wells where the gravel pack extends
from land surface to the aquifer or extends into an
aquifer containing mineralized or undesirable
water.
• The pulling of the well casing in a gravel packed
well that leaves a gravel conduit extending from
the surface to the aguifer.
• Insufficient casing and improper grouting of casing
in water wells in basalt formations.
• Improper location of perforations.
• Improper cr inadequate welding of casing joints.
• Leaky pitless adapters.
• Leaky well seals.
These obvious hazards have an obvious solution in the
application of adequate standards for the construction and
abandonment of water wells by competent well drillers.
94
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^ and Abandoned^Wells
Most dry holes are not dry. The term "dry hole" is really
an indicator of the failure of a hole in the ground to
produce a desired fluid in a satisfactory amount, be it
crude oil, natural gas, water or whatever.
As with most other human failures, the tendency is to avoid
throwing good money after bad, to walk away and to forget
it. Such a philosophy often leaves an improperly plugged
hole that provides a direct and speedy route for the
movement of surface pollutants into good aquifers. It also
leads to the direct and speedy movement of fluids from
contaminated aquifers to good aquifers, and to the surface.
It should be noted that many states have regulations
governing the plugging of abandoned wells, especially oil
and gas wells.
Control measures are similar to those for successful wells,
that is, the effective sealing by an impermeable substance
of routes of unwanted vertical communication.
95
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References
1. American Gas Association, Inc., Survey of Gas Storage
Facilities in UnjLted States and Canadat New York "(1967) .
2. American Gas Association, Inc., The Underground Storage
of Gas in the United States^ New York""~(i971) . ~"
3. Arlin, Z. E., "Deep-Well Disposal of Urainum Tailing
Water," Proceedings _2nd Conference on Ground Disposal of
EJ^iSfJciriy.^ 5il .§£§.§.£. Chalk River, Canada, U.S. Atomic
Energy~Commission THH7628, Bk. 2, pp 356-360 (1962).
U. Ballentine, R.K., Reznek, S.R., and Hall, C.W., Subs_urface
Poiiiiii0!! Problems in the United States^ US.
Environmental Protection Agency Technical Studies Report
TS-00-72-02, Washington, D.C. (1972).
5. Belter, W.G., "Deep Disposal Systems for Radioactive
Wastes," Underground Waste Management and Environmental
Implications^ American Association of Petroleum
Geologists Memoir 18, Tulsa, Oklahama (1972) .
6. Bureau of Reclamation, Geothermal Resource
Investigatipns f Imperial Va^
^
Developmental Concepts^ US Department of the Interior,
Boulder CityT Nevada, 58 pp (1972).
7. Chasteen, A.J., "Geothermal Energy - Growth Spurred on
by 'Powerful Motives'", ^Mining Engineering^ Society of
Mining Engineers of AIME, Vol. 24, No7~"lO, pp 100-102
(1972) .
8. Cook. T.D. (editor), Underground Waste Management and
Environmental Imp.licati.onsx American Association of
Petroleum Geologists Memior, Tulsa, Oklahoma, 412 pp
(1972) .
9. de Laguna, W,, "Importance of Deep Permeable Disposal
Formations in Location of a Large Nuclear-Fuel
Reprocessing Plant," Disjgosal in Geologic Basins - Stud1
Qf £§servoir Strata^ American Association of Petroleum
Geologists~Memoir 10, pp 21-31 (1968),
96
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10. de Laguna, W.r et al. Safety Analysis of Waste Disposal
by. SY-dr^Jiii0. ZJSStujiiSS 1J= 2^lS S^^Sx <->a'c Ridge National
Laboratory~*Report 4665, Oak Ridge, Tennessee, pp 1-6
(1971).
11. Donaldson, B.C., Subsurface Disposal of Industrial
Wastes in the United Statejx UjS. Bureau~~of Mines
Information Circular 82127^34 pp (1964).
12. Dow Chemical Company (Freeport, Texas), "Final Disposal
of Effluent Brines from Inland Desalting Plants,"
Environment Pollution and Control^ Report OSW-RDPR-72-
817 (T§72)7
13. Ferris, J.G., "Response of Hydrologic Systems to Waste
Storage," Underground Waste Management and Environmental
IffiEii£§ti°H5x American Association of Petroleum
Geologists Memoir 18f Tulsa, Oklahoma, pp 126-130
(1972) .
14. Dryberger, J.S., Rehabilitation of a Brine-Polluted
A3uiferx US. Environmental Protection Agency, ~*
Environmental Protection Technology Series EPA^R2-014,
Washington, C.C., 61 pp (1972).
15. Galley, J.E. (editor). Subsurface Disposal in Geologic
Basins^ American Association ol Petroleum Geologist
Memoir 10, TulFi, Oklahama (1968).
16. Galley, J.E., "Geologic Basin Studies as Related to
Deep-Well Disposal," Proceedings 2nd Conference on
Ground Disposal of Radioactive Wajstes^ Chalk River,
Canada, UjS. Atomic Energy Commission TID-7628, Bk. 2, pp
347-335 (1962) .
17. Goolsby, D.A., "Hydrogeochemical Effects of Injecting
Wastes Into a Limestone Aquifer Near Pensacola,
Florida," Ground Waterx Vol. 9, No. 1, pp 13-19 (1971) .
18. Hallden, O.S., "Underground Natural Gas Storage
(Hers cher Dome) ," Ground Water Cont jm in at ign^ US.
Department of Health, Education,"and Welfare, R.A. Taft
Sanitary Engineering Center, Technical Report W61-5,
Cincinnati, Chio, 218 pp (1961).
97
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19. Hubbert, M.K., and Willis, D.G., "Mechanics of Hydraulic
Fracturing," Journal of PetroJLeum Technology^ American
Institute of Mining, Metallurgical Engineers Petroleum
Division, Trans., T.P. 4597, pp 153-168 (1957).
20. Iglehart, C.F., "North American Drilling Activity in
1971," Bulletin^ American Association of Petroleum
Geologists^. Vol. 56 No.7, pp 7i45-lT74~"(1 974) .
21. Interstate Oil Compact Commission, Water. Problems
Associated with Oil Production in the United States,
Oklahoma, City, Oklahoma, 88 pp (1964)7
22. Irwin, J.H., and Morton, R.B., Hydrogeologic Information
on The Glor^ieta Sandstone and the Ogallala Formation in
the Oklahoma Panhandlfe and Adjoining Area^ as Related to
Underground Waste Disposalx U.S. Geological Survey
Circular 630,~26 pp (1969f.
23. Ives, R.E., and Eddy, G.E., Subsurface Disposal of
Industrial Was^tes^ Interstate Oil Compact Commission,
Oklahoma City, Oklahoma, 109 pp (1968).
24. Love, J.D., and Hoover, L., A Summary of the Geology of
Sedimentary Basins of the United Statesx with Reference
to the Disposal of Rjadioa£tiye~'wasteSjL U.S. Geological "
Survey Trace Elements inv.^Report 76^ (open file), 92 pp
(1960) .
25. McKinney, W.A., "Solution Mining," Mining Engineering,
pp 5657, February (1973).
26 Ostroff, A.G., Introduction to Oilfield Water
Technology,. Prentice-Hall, Inc. , Englewood Cliffs, New
Jersey, 412 pp (1965).
27. Pasini, J., Ill, et al, "Plugging Abandoned Gas and Oil
wells," Mining Congress Journal^ pp 37-42, December
(1972) . ~*~""
98
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28. Pernichele, A.E., "Geohydrology," Minjirvg Engineering^ pp
67-68, February (1973).
29. Rima, R., et al, Subsurface Waste Disposal by Means of
Wel^s - A Selective Annotated Bibliog^aghy, US. Geological
Survey Water - Supply Paper 2020 (T971).
30. Roedder, E., Problems in the Disposal of Acid Aluminum
te High-Level M^i2i£ii^ Waste Solutions Ey
n Into Deeglying Permeable Formations^ US.
Geological"Survey Bulletin 1088, 65~"pp (1959).
31 Selm, R.P., and Hulse, B.T., "Deep-Well Disposal of
Industrial Wastes," .1.4th Industrial Waste Conference
Proceedings^ Purdue University Engineering Extension
Series No. 104 pp 566-586 (1959).
32. US Department of the Interior, Geothermal Leasing
Program^ NTIS Accession No. PB 203 10^2-D, Washington,
D.C. (1971) .
33. US. Environmental Protection Agency, Subsurface Water
Pollution f A Selective Annotated BibliqgraghyJ Part J
Subsurface WaSte In1ectione office of Water Programs,
Washington, 5Tc., 156 pp "(1972) .
34. Van Everdingen, A.F., "Fluid Mechanics of Deep-Well
Disposals," Subsurface Disposal in Geologic Baains - A
Study of Re^ejcvoir Strata^ American Association of
Petroleum Geologists Memoir 10, Tulsa, Oklahoma, pp 32-
42 (1968) .
35. Warner, D.L., Deep-We11 Injection of LicQiid Waste^ US.
Public Health Service Environmental Publication No.
999-WP-21, 55 pp (1965).
36. Warner, D.L., "Deep-Well Waste Injection -- Reaction
with Aquifer Water," Proceedingsx American Society of
Civil Engineers^ Vol. 92, No SA4, pp 45-69 (1966).
37. Warner, D.L., Deep.~Wells for Industrj.al Waste Infection
in the United States - Sununary of Datax FeSeral Water
Pollution Control Administration,. Water Pollution
Control Research Service Publication No. WP-20-10, 45 pp
(1967) .
99
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38. Warner, D.L., "Subsurface Disposal of Liquid Industrial
Wastes by Deep-Well Injection," Subsurface pijsgojsaj. in
Geologic BasJLns - A Study of. Reservoir Strataf American
Association of"petroleum Geologists Memoir To, Tulsa,
Oklahoma, pp 11-20 (1968).
39. Warner, D.L., Subsurface Industrial Wastewater Injection
ifi liiinoijx Illinois Institute for Environmental
Quality Document N. 72-2, 125 pp (1972).
40. Warner, D.L., Survey of Jndvis trial Waste Injection
Wells^ 3 Vols. , Final Report, U.S. Geological Survey
Contract No. 14-080001-12280, University of Missouri,
Rolla, Missouri (1972).
41. Wilmoth, B.M., "Occurrence of Salty Groundwater and
Meteoric Flushing of contaminated Aquifers," Proceedings
of National Grcundwater Quall-ty Synposjum^ EPA Water
Pollution Control Research Series 16060 GRB 08/71
(1971).
42. Young, A., and Galley, J.E. (editors), Fluids in
Subsorface Environments^ American Association of
Petroleum Geologists Memior 4, Tulsa, Oklahoma, 414 pp
(1965).
100
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INJECTION INTO FRESH WATER AQUIFERS
Scope^of the Problem
Although most of the estimated 15 million wells in the
United States are used for the production of fresh water,
many thousands of wells in various parts of the country have
been and are still being used only for the disposal of
pollutants into fresh water aquifers. This practice has
been followed, fcr example, by the petroleum industry in
some areas for getting rid of brines and by other industries
for disposing of chemical wastes. Fuhriman and Barton
(1971) , referring to ground water pollution in the
southwestern United States, state that "occasionally,
industries or others have used shallow injection wells to
dispose of liquid wastes," and cite as an example electronic
industries that disposed of metalplating wastes by means of
injection wells in Arizona.
In parts of Florida and Ohio, wells tapping limestone
aquifers have been used to dispose of domestic sewage from
individual homes. Similarly, in Oregon (Sceva, 1968, Oregon
State Sanitary Authority, 1967) domestic sewage effluent is
discharged from septic tanks into deep rock wells drilled
into basalt aquifers (Figure C). For the past several
101
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decades thousands of wells in New York, in California, and
in several midwestern states have been used to inject heated
water from cooling systems into fresh water aquifers.
In the Snake River Plain of Idaho, wells are widely used to
dispose of wastes into the underlying permeable basalt
aquifer. A recent inventory in the area indicates that
there are approximately 1500 wells for disposal of surface
runoff and waste irrigation water, perhaps 2000 wells for
disposal of sewage, and additional wells for street drainage
and industrial use. At the National Reactor Testing
Station, low->-level aqueous radioactive wastes have been
discharged into the same basalt aquifer through a drilled
well since 1953 (Jones, 1961).
102
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Land Surface
_\ _
Disposal Well
'•;-.:;'-.: '••.;•''•••'• '".:.'-;v;-'. KO:.;': •••"':> ••'-• ^: ;^V'-. •'. ^ ydTT?^;
f;iet:>:i^^^?^^^^
;V.:.-'./ Soil;
^'^Surface Casing
\
1X "N
N
^ "X (
Basalt
- Rock _ v
\- \
S
/ \
\
Crevices
Figure C Diagram of domestic sewage disposal system
employing a disposal well in the middle-
Deschutes Basin, Oregon (after Sceva, 1968)
103
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In recent years, as pressure on municipalities to abate
pollution of surface waters has increased, greater attention
has been given to the possibility of injecting treated
municipal sewage into wells penetrating fresh water
aquifers. Several of the proposed schemes not only would
solve a sewage-disposal problem but also would help to
recharge fresh-water aquifers or to establish hydraulic
barriers against salt-water encroachment in fresh-water
aquifers. Advanced pilot experiments are being conducted
along these lines in Long Island (Vecchioli and Ku, 1972)
and in California (Baier and Wesner, 1971). The procedure
is relatively costly because the sewage must be given at
least secondary treatment, and preferably tertiary
treatment, in order to prevent clogging the injection wells
and to reduce or prevent significant contamination of the
aquifer.
Modification of the existing quality of the native ground
water caused by subsurface disposal of wastes through a well
depends on a variety of factors including the composition of
the native water, the amount and composition of the injected
waste fluid, the rate at which the injection takes place,
the permeability of the aquifer, the type of construction
104
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and life expectancy of the well, and the kinds of biological
and chemical degradation that may take place within the well
and the aquifer. In general, for economic reasons, wells
used for disposal of contaminated liquids in fresh-water
aquifers tap the shallowest available aquifer, commonly a
water-table aquifer. Some disposal wells, however, are
terminated at greater depths in confined fresh water
aquifers.
Environmental Consequences
Initially, injection of contaminated liquids through wells
into fresh-water aquifers causes degradation of the chemical
and bacteriological quality of the ground water in the
immediate vicinity of the injection facilities. Eventually,
the degradation spreads over a wider region and may
ultimately extend into surface waters that are hydraulically
connected with the receiving aquifer. If the water-level
cones of depression around nearby operating water-supply
wells are large enough to include the injection site, or if
the wells are down-gradient along natural flow lines from
the injection site, contamination of these wells may take
place. Another potential effect in some hydrogeologic
environments is irovement of the contaminated water from the
105
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injection zone into overlying or underlying fresh-water
aquifers.
Nature of Pollutants
The principal kinds of contaminated fluids that are
intentionally injected through wells into fresh-water
aquifers other than those from agricultural and mining
wastes, are cooling water, sewage, storm water, and
industrial wastes.
In the case of cooling water returned to the same aquifer
from which it has been pumped, the quality of the water may
be unchanged from that of the native water except for an
increase in temperature. Increased solubility of aquifer
materials due to a rise in temperature is believed to be
insignificant, except perhaps in carbonate aquifers. In
some instances sequestering agents,such as complex
polyphosphate-based chemicals added to the water to inhibit
oxidation of iron, may become a source of pollution to an
aquifer.
Domestic sewage being disposed of into individual household
wells is a waste highly polluted with organic and inorganic
106
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substances, bacteria, and viruses. It may receive little
natural treatment during passage through septic tanks and
cesspools except for the settling of the solids, some
biochemical degradation of the wastes, and filtration of
part of the large bacterial population. On the other hand,
the quality of the municipal sewage effluent released for
disposal into wells depends on the degree of treatment
before disposal and the source of the sewage. Municipal
sewage generally consists mainly of domestic wastes with a
high content of dissolved solids, including nitrogen-cycle
constituents, phosphates, sulfates, chlorides, and
detergents (methylene-blue active substances, or MBAS). In
some localities municipal sewage contains substantial
amounts of industrial wastes. Different degrees of
treatment may remove or reduce the concentrations of certain
constituents, but even with the most advanced forms of
sewage treatment, many dissolved constituents, including
heavy metals, remain in the wastes.
The chemical qualities of tertiary treated sewage, native
ground water arid water recovered from observation wells,
from an experimental injection study in Long Island, New
York, are shown in Table 12. The concentrations of ammonia.
107
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iron, phosphate, sulfate, and other constituents, as well as
the dissolved solids content,were significantly higher than
those of the native ground water. No analyses of the
treated waste were made for heavy metal?, viruses, or other
objectionable constituents. The bacterial count in the
treated sewage was low due to heavy chlorination before
injection.
Storm-water runoff generally has a low dissolved-solids
content. However, the initial slug of storm water may be
contaminated with animal excrement, pesticides, fertilizer
nitrate from lawns, organics from combustion of petroleum
products, rubber from tires, bacteria, viruses, and other
contaminants. Where deicing salts are applied to roads in
the winter, the chloride content of the storm water may rise
temporarily to several thousand mg/1.
Industrial wastes injected through wells range widely in
composition and toxicity, depending on the particular
industrial operation and the degree of treatment of the
wastes before disposal. Plating wastes, pickling wastes,
acids, and other toxic materials, are some of the more
108
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common fluids disposed of through wells into fresh water
actuifers.
Contaminated Water Recoverd
from Observation Wells
Constituent
Total iron
Free CC-2
Fluoride
Ammonia nitrogen
Albuminoid nitrogen
Nitrite nitrogen
Nitrate nitrogen
Oxygen consumed
Chloride
Total hardness
Total alkalinity
PH
Total solids
MBAS
Calcium hardness
Total phosphate
Orthophosphate
Sulfate
Silica
Calcium
Magnesium
Sodium
Potassium
Tertiary Treated
Injection water
(mg/)2)
0.24
21
.26
25
.36
.00
<05
3
13
12
11
7.0
357
.02
42
3.6
3.1
137
14
18
5.2
69
11
Native Groundwater
Depth 171m
(mg/fi)
0.6
-
.01
-
—
_
.00
-
3.7
—
_
5.6
23
-
—
.01
-
4.1
7.4
.34
.17
3.7
.60
Depth 146m;
Distance 6.1m
(mg/£)
0.91
105
.23
18.5
.24
<.001
<.05
9
Lf
74
42
33
5.8
321
<.02
22
.60
.50
138
10
8.2
4.2
67
9
Depth 140m;
Distance 30m
(mg/B)
1.30
100
<.10
1.38
.04
<.001
<.05
1
24
34
6
5.1
123
<.02
16
.02
<.01
54
8.0
7.2
3.3
22
1.6
Table 12 Selected chemical-quality characteristics of
native water and tertiary treated injection
water (after Vecchiolo and Ku, 1972) .
109
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Pollution Movement
In principle, any well that produces water will also accept
water. The rate of acceptance is dependent on the nature of
the injected fluid, the hydraulic properties of the aquifer,
and other factors. In some wells penetrating very permeable
aquifers, water can be introduced under gravity conditions
at rates that may be as high as several decaliters per
second or more without causing overflows. In contrast, a
well penetrating a very poor aquifer may accept only a
fraction of a liter per second by gravity flow. If pumps
are installed so that the fluid is injected under pressure,
the rate of injection can often be substantially increased.
The rate of injection is governed by the porosity,
permeability and thickness of the aquifer, the depth to the
natural water level in the well, the diameter of the well,
the area of openings in the well screen, and the chemical
compatibility of the injected fluid with the native ground
water. If the fluid being injected contains suspended
materials or air bubbles, for instance, rapid clogging of the
aquifer can occur so that the injection rate falls off
sharply. Growth of certain kinds of bacteria and formation
of chemical precipitates within the well and the adjacent
110
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aquifer also can interfere with injection. In the case of a
water-table aquifer a further limitation on the rate of
injection is that an induced rise of the ground water level
may cause breakthrough and overflow at the land surface.
Injection of fluid through a well creates a local ground
water mound in an unconfined aquifer and a pressure mound in
a confined aquifer. These mounds are essentially mirror
images of the water-level cones of depression that develop
around pumping wells tapping the same types of aquifers.
The configuration of a particular mound is generally
symmetrical, with the maximum rise in water level being
observed at the well. Hypothetical shapes of contaminated
water bodies in homogeneous unconfined and confined aquifers
are shown in Figure D. Departures from these shapes may
develop where aquifer lithologies are not uniform and where
the natural ground water flow is rapid.
Ill
-------
WELL
Liquid contaminants
— Aquiclude"^— —__—— — — — -—_—— ——- —
A. Water table aquifer
WELL _-*-" Liquid contaminants
at-New piezometric surface-
Original— ^-^=*>
B. Artesian aquifer
Figure D Hypothetical pattern of flow of contaminated
water (shaded) injected through wells into
water table and artesian aquifers (after
Deutsch, 1963).
112
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After it has entered the saturated zone the injected fluid
begins to move radially away from the well, displacing the
native qround water in its path and creating a zone of mixed
water along the perimeter of the contaminated body. The
polluted water mcves slowly in the direction of the
hydraulic gradient toward a point of discharge which may be
a well, a spring, or a surface-water body. Where injection
wells leak due to corrosion, casing breaks or poor
construction,the contaminated water may move into fresh-
water aquifers above or below the injection zone.
Ex a m21 e s_ o f _t he _ Us e_o f _I n jec t i on_ We 11 s
Since 1965 a pilot experiment on recharging tertiary-treated
sewage in order to create a hydraulic barrier against
salt-water encroachment has been conducted by the U.S.
Geological Survey,in cooperation with the Nassau County
Department of Public Works,at Bay Park, Long Island
(Vecchioli and Ku. 1972). A specially constructed injection
well (Cohen and Eurfor, 1966), 146 meters (480 feet) deep,
with a fiberglass casing, stainless steel screen, and
auxiliary monitoring wells at depths ranging from about 30
to 200 meters (100 to 700 feet), were installed to
investigate the hydraulic and geochemical problems
113
-------
associated with the injection of treated sewage into a
confined.sand aquifer used for public-water supply. The
injected water moved radially from the well as a thin body
in the injection zone and has been detected by monitoring
wells as much as 60 meters (200 feet) away. As shown in
Table 12, significantly higher concentrations of iron,
ammonia, sulfate, chloride, sodium, and other dissolved
constituents were present in the water at distances of 6.1
meters and 30.5 meters (20 feet and 100 feet), than in the
native ground water. Bacteria were apparently filtered out
after about 6.1 meters (20 feet) of travel. The
experimental results indicated that even low turbidity of
the effluent and bacterial growth around the well screen can
cause clogging and excessive head build up in the injection
well. Similar experiments in California on recharging fresh-
water aquifers with Colorado River water and with reclaimed
sewage (McGauhey and Krone, 1954), mainly as a barrier
against sea-water encroachment, have been successfully
conducted. Some barrier systems using highly treated river
water are operational. Baier and Wesner (1971) have
described experiments by Orange County Water District in
which tertiary-treated effluent from a trickling filter
sewage plant was injected into unconsolidated aquifers at
114
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depths of about 30 to 100 meters (100 to 350 feet). The
experiments indicated that after about 150 meters (500 feet)
of travel, the injected water was free of bacteria and
toxic substances, and the ammonia content was substantially
reduced. However, the hardness and alkalinity of the water
increased, the water had a musty odor and taste, and the
dissolved solids content exceeded 1,000 mg/1. Additional
pretreatment of the reclaimed waste water will improve the
quality of the water intended for injection, and the
dissolved-solids content will be reduced to drinking water
standards by mixing reclaimed waste water with desalted sea
water before injection.
Since the early 1930's, the State of New York has required
that water pumped from wells on Long Island at rates of 2.8
Ips (45gpm) or more must be returned, through a closed
system of specially constructed recharge wells, into the
same aquifer from which the water was pumped. This
requirement was imposed because heavy pumping had caused a
sharp decline in ground water levels in western Long Island,
with coastal encroachment of sea water. The heated effluent
returned to the ground, which may range from 5 to 17<>C
warmer than the natural ground water, has increased the
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local temperature of shallow aquifers (Leggette and
Brashears, 1938) . Warming of the ground water, although of
concern to users of ground water for cooling, has been
regarded as less detrimental than the saltwater encroachment
that could result from declining ground water levels.
In parts of western Long Island, stormwater that collects at
street intersections subject to flooding is disposed of into
dry wells that act as drains. The wells are lined with
large-diameter, precast, perforated concrete rings. The
stormwater moves downward through the wells into a shallow
aquifer. Hundreds of dry wells are also used for highway
drainage in other parts of the country; notable are those in
the Fresno area cf California (Gong-Guy, in Schiff, 1963).
In a few places, wells also have been drilled within ponds
to drain them. Erainage wells commonly provide a bypass for
potential vertical movement of inorganic and organic
contaminants and bacteria into an underlying aquifer.
Control^Methods
Where injection of wastes through wells into fresh-water
aquifers is proposed r is in progress, a hydrogeological
investigation shculd be undertaken as a first measure to
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control potential ground water pollution. This should
include:
1. Definition of the hydrogeologic environment and the
factors affecting the ground water flow.
2. Existing or planned nearby wells should be located.
3. The directions and rate of movement of the
potential contaminated fluid should be ascertained
so that estimates can be made of how much time will
elapse before the arrival of the contaminated water
at nearby wells.
4. Studies should be undertaken to determine the
possibility of inter- and intra-aquifer movement of
the injected water.
5. Information should be compiled on the chemical,
biological, and physical properties of the waste
fluids; the degree of pretreatment needed; and the
compatibility of the treated fluids with the native
ground water.
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6. An evaluation should be made of the most suitable
locations and spacings of injection wells and of
the rate of injection.
7. Consideration should also be given to future land
use at the injection-well sites.
Where the threat from contaminated ground water is severe,
steps may have to be taken to block the underground flow of
the waste fluids or to actually remove the fluids by
pumping. Blocking of the movement of the contaminant can be
accomplished by constructing physical subsurface barriers
although this is net an economically feasible solution in
most hydrogeologic environments. Diverting the flow by
creating a hydraulic barrier is another approach that may be
implemented in many places. This can be accomplished by
injecting fresh water through wells installed across the
path of flow or by pumping from wells so as to induce the
contaminants to flew toward these wells.
Pumping polluted fluids back out of the ground may create a
new pollution problem where the wastes are pumped into
surface water. However if facilities can be provided for
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prooer treatment and disposal of the pumped water, pumping
from wells can be a practicable solution.
Alternatives to disposing of wastes through injection
should, of course, be examined. A careful evaluation of
alternatives is required to avoid adopting an expedient that
may prove to have ether, and perhaps more harmful, effects.
Sewering for example, which exports the waste, can have
deleterious effects due to loss of recharge and consequent
lowering of water levels,possibly causing salt-water
intrusion. In the case of cooling water being returned to
the aquifer from which it is drawn an alternative is to use
atmospheric heat exchangers instead of cooling water. Here
the loss of efficiency of the cooling system must be
considered; more electrical energy may be required, with
attendent air and thermal pollution problems. Also the
undesirable "heat island" effect noted in large cities would
be further increased by widespread use of atmospheric heat
exchangers in place of the ground water for cooling.
Halting the disposal of wastes into wells may, in some
instances, be highly desirable but it should be noted that
halting the injection represents only a partial pollution
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control measure; fluids already injected will continue to
pollute the aquifer.
MpHi£ or inc[_ Procedures
After a clear understanding has been developed of the
hydrogeologic environment and of the mechanisms of
contamination, a monitoring system should be designed and
implemented to provide continuing surveillance of polluted
water, and of the efficiency of any control measures that
may be instituted. Depending on local conditons it may be
necessary to construct a series of wells at different depths
in the polluted aquifer and at scattered nearby locations.
Periodic monitoring of these wells for chemical content of
the ground water, and changes of ground water levels, can
provide valuable data on the behavior of the underground
contamination,and on the environmental threats to water
wells or to other fresh-water resources in the vicinity.
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References
1. Baier, D.C., and Wesner, G.M., "Reclaimed Waste Water
for Ground-Water Recharge," Jour. American Water
B§ sources Assoc^^ v.7, no. 5, pp. 99T~TooT (T971)".
2. Cohen, Philip, and Durfor, C.N, , "Design and
Construction of a Unique Injection Well on Long island,
New York," geological Survey Research, ^96^ U.. S. Geol^
Survey Prof7~Papjer 550-D^ pp. D253-D257 (1966).
3. Deutsch, Morris, Ground-Water Contamination and Legal
Controls i.n Michicjan^ U." S, Geol. Survey Water-supply
Paper 1691, 79~pp. (1963) .
4. Fuhriman, O.K., and Barton, J.R., Ground Water Pollution
in Arizona^. Calif or niax Nevadax and Utah^ U. S.
Environmental Protection Agency, Water Pollution Control
Research Series 16060, 249 pp. (1971).
5. Jones. P.H. , Sydrology of Waste Disposal National
Reactor Testing Station^ .IdahOj. U. s. Geol. Survey
Interim Report for U. s. Atomic Energy Comm. , Idaho
Falls, Idaho (1961) .
6. Leggette, R.M. and Brashears, M.L., Jr., "Ground Water
for Air Conditioning on Long Island, New York," Trans.
Amer., Geoghys^ Union^ pp. U12-U18 (1938). "
7. McGauhey, P.H. , and Krone, P. B. , Report on the
Investigation cf Travel of Pollution^ California State
Water Pollution Control Board, Publ. no. 5, 218 pp.
(1954) .
8. Oregon State Sanitary Authority, Water .Quaj-ity Control
iEt Qregon, Oregon State Sanitary Authority, vol. 1, 113
pp. (1967).
9. Sceva, J.E. , Liquid Waste Disposal j.n the Lava Terr an es
2l Ceirtrs! Orecjonx U. S. Federal Water Pollution Control
Admin., Northwest Region, Pacific Northwest Water
Laboratory, Corvallis, Oregon (1968).
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10. Schiff, Leonard, (Editor), Ground Water E§£|j3rge and
Ground Water Basin Managementf Proc. 1963 Biennial
Conference Ground Water Recharge Center, Fresno, Calif.
(1963) .
11. Vecchioli, Hchn, and Ku, F.H., Preliminary Results of
iQJSSiiDS Siahly Treated Sewage Plant Effluent into a
Deep and Sand^Aquifer at Ba^ Parkx New York^ U. S. Geol,
Survey Prof .~Paper 751A7 "l4 pp. (1972) .
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SECTION III - POLLUTION FROM OTHER SUBSURFACE EXCAVATIONS
LAGOONS, BASINS, AND PITS
In general, a lagoon comprises a natural depression in the
land or a sector of some bay, estuary, or wetland area diked
off from the remainder. No sharp line of definition
distinguishes it from a basin, which is most commonly
constructed by formal diking or by a combination of
excavating and diking. Pits are distinguished from lagoons
and basins by a smaller ratio of surface area to depth.
Unlike excavations used in septic systems or in landfill
operations, lagocns, basins, and pits are usually open to
the atmosphere, although pits and small basins may sometimes
be placed under a roof. Some are intended to discharge
liquid to the soil system and hence to the ground water,
others are designed to be watertight. The former are,
therefore, unlined structures sited on good infiltrative
surfaces; the later are lined with puddled clay, concrete,
asphalt, metal, or plastic sheeting. Thus, both by design
and by accident or failure, this type of structure is of
concern in the context of ground water quality.
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Lagoons and basins are adapted to a wide spectrum of
municipal and industrial uses including storage, processing,
or waste treatment on a large scale. For example, the
unlined lagoon or basin may serve as a large septic tank for
raw sewage, a secondary or tertiary sewage oxidation pond,
or as a spreading basin for disposing of effluent from
treatment ponds cr conventional waste water treatment plants
by ground water recharge. In industry the unlined system
may serve as a cooling pond or to hold hot waste water until
its temperature is suitable for discharge to surface waters,
or to store waste water for later discharge into streams
during flood flows or for application to the land during the
growing season. Seme unlined lagoons are used for a special
purpose, such as evaporating ponds, to concentrate and recover
salt from saline water. Lined basins are used for a number
of purposes, including evaporation ponds for concentrating
salts or process brines. Recovery of minerals, or more
economic disposal of the concentrate, may be the motivating
factor. In oil fields, refineries, and chemical processing
plants, lined pits are used as holding sumps for brines or
wastes as a stage in disposal by well injection,or other
acceptable procedure. In the East Bay area of California, a
lined basin has served as a receiving sump for fruit and
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vegetable cannery wastes to be barged to sea or hauled to
land disposal sites.
Unlined pits serve to a limited extent in sewerage; examples
include pit privies and cesspools or percolation devices in
septic systems. They are also widely used to dispose of
storm water from roof drains. In California both pits and
basins are used to dispose of storm water which would
otherwise collect in highway underpasses and interfere with
traffic.
Lined pits have historically been used in industry for
processes ranging from tanning of animal hides to metal
plating. They are commonly used to house sewage pumps below
the ground level. In both industry and municipal sewerage,
they are used as intake sumps in pumping installations.
Although lined pits are commonly concrete or metal
structures, undetected leakage of highly concentrated
pollutants can have a significant effect on ground water.
Sc o£e_ of_P r ob le m
Data by which to evaluate the existing scope of the problem
of municipal and industrial waste lagoons and similar open
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excavations in relation to ground water quality have not
been assembled and analyzed. State health departments and
water quality control boards can cite instances in which
ponded contaminants have created a local pollution problem.
To assess the degree to which the use of lagoons, basins,
and pits in fact degrade ground water quality will require
an extensive survey of the literature and of the practice of
ponding wastes and process materials. The present outlook
is that the need for such an assessment will become
increasingly great with time. Two factors support this
conclusion:
• As institutionalized in Public Law 92-500, there is
a growing reluctance of regulatory agencies to
permit waste discharges to surface waters, thus
requiring either land disposal of sewage effluents
or the creation of an increasing volume of process
brines in achieving an acceptable effluent quality; and
• A growing tendency to require industry to process
its own wastes prior to discharge to the municipal
sewer, thus creating more need to use lagoons and
basins either for waste processing or for managing
waste processing brines.
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Both of these developments suggest a need to control the
pathways by which contaminants may move from ponds to ground
water and to monitor the effectiveness of control measures.
Potential Hazard tc^Ground Water
The potential of sewage lagoons to degrade ground water
quality is essentially the same as that of septic systems.
An extensive survey of the literature (McGauhey and Krone,
1967) shows that a continuously inundated soil soon clogs to
the extent that the infiltration rate is reduced below the
minimum for an acceptable infiltration system. If the
ground water surface is too close to the lagoon bottom, a
hanging column of water will be supported by surface tension
and the soil will not drain. Clogging will then continue
indefinitely even though no new liquid is added to the
system. A spreading pond designed to discharge effluent to
the ground water must, therefore, be loaded and rested
intermittently to maintain an acceptable recharge rate. If,
however, isolating the contents of the lagoon from the
ground water is the objective of the system, a low
infiltration rate may still mean an undesirable quantity of
polluted water passing the water-soil interface. The
pollutants carried downward with percolating water from a
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sewage lagoon are those described in the section on septic
tanks. Not all of the salts introduced to the ground water
originate in domestic use. In some instances, such as that
of Colorado River water delivered to Southern California,
the mineral content of the imported water may be higher than
that of the local ground water.
Liquids percolating from lagoons or basins used by industry
have a greater potential to degrade ground water than does
domestic sewage. Chromates, gasoline, phenols, picric acid,
and miscellaneous chemicals have been observed to travel
long distances with percolating ground water. Unlined
lagoons, basins, and pits are commonly used by industry for
the storage of liquid raw materials and waste effluent.
Most of these facilities are simply open excavations or
diked depressions in which the liquid is temporarily or
permanently stored. Few have been designed with proper
consideration to water tightness, so that leakage of
potential contaminants into the underlying ground water
reservoir is very common even though the leakage may seldom
be known to exist. Liquids stored in industrial lagoons,
basins, and pits may contain brines, arsenic compounds,
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heavy metals, acids, gasoline products, phenols, radioactive
substances, and many other miscellaneous chemicals.
Where storage areas have been actively used for many years
and leakage through the sides and bottom of a particular
lagoon or basin has taken place, the quantity of
contaminated ground water can be significant and the plume
of polluted liquid may have traveled long distances with the
percolating ground water. In some instances, the first
realization that extensive ground water pollution has
occurred may come when the plume reaches a natural discharge
area at a stream and contamination of surface waters is
noted.
An example of the fate and environmental consequences of a
leaky basin containing metal^plating waste effluent from an
industrial plant is given in Perlmutter and Lieber (1970).
Plating wastes containing cadmium and hexavalent chromium
seeped down from disposal basins into the upper glacial
aquifer of southeastern Nassau County, New York. The
seepage formed a plume of contaminated water over 1200
meters (4,000 feet) long, about 300 meters (1,000 feet)
wide, and as much as 20 meters (70 feet) thick. Some of the
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contaminated ground water is being discharged naturally into
a small creek that drains the aquifer. The maximum observed
concentration of hexavalent chromium in the ground water was
about. 40 mg/1, and concentrations of cadmium have been
observed as high as 10 mg/1.
In another case in New Jersey, unlined waste lagoons
constructed in sand and gravel beds leaked over 75 million
liters (20 million gallons) of effluent into the upper 6
meters (20 feet) of aquifer over a period of only a few
years. The contaminated ground water contains high
concentrations of phenols, chromium, zinc, and nickel.
Control,Methods
In the case of lagoons or basins for deliberate disposal of
sewage effluents, or surface runoff by ground water
recharge, controls specifically pertinent to ground water
protection are essentially self-generating — the system
simply will not work if not properly designed. The first
control measure in ground water protection from spreading
basins is to apply existing knowledge to their siting and
design. Existing engineering and hydrogeologic knowledge
would prohibit the construction of such systems directly in
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the aquifer; require adequate distance between the
infiltrative surface and the ground water surface to permit
drainage; and prohibit construction in faulted or fractured
strata or in unsuitable soils.
Control of industrial waste discharges to the ground water
is a complex problem. In a state with a highly organized
water pollution control agency (e.g., California), individual
permits are issued on the basis of adequate design and
surveillance programs. Because of the variety of industrial
wastes and the varied situations in which they occur,
control of ground water pollution from such wastes depends
both upon proper design of new systems and upon discovery
and correction of existing poor systems. Methods for
controlling ground water pollution from industrial lagoons,
basins, and pits include:
• Pretreatment of wastes for removal of at least the
toxic chemicals.
• Lining with impervious barriers of all lagoons,
basins, and pits that contain noxious fluids. This
is the principal control technique recommended by
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some agencies, such as the Delaware River Basin
Commission.
• Use barrier wells, pumped to intercept plumes of
contaminated ground water from existing industrial
basins where leakage has occurred. Such wells have
been used successfully, but can be costly to
install and operate. The water removed must be
treated before redisposa}..
• Banning the use of pits. An example is found in
Kansas, where thousands of brine pits were used by
the oil industry. Kansas was the first State to
ban their use because of the contamination of
ground water.
• Locating and identifying unauthorized pits on
industrial sites, on a case-by-case basis, and
apply appropriate regulatory action.
Monitoring Procedures
Lagoons, basins, and pits represent pollution sources which
may be of significance to ground water quality degradation.
Therefore, a program involving special monitoring wells on a
priority basis is a possible approach.
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A program of periodic sampling and evaluation of data from
existing wells, selected for their potential to reveal both
normal ground water quality and point contamination, is
another monitoring approach. Accompanying this should be an
evaluation of the control measures themselves to assure that
ground water protection is indeed being accomplished.
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References
1. Anon., "Well Pollution by Chromates in Douglas,
Michigan," Michigan Water ^ Works News (1947).
2. California State Water Pollution Board, Wastewater
Rec la mat ion in Re la ti on to Grgundwater^ Pollution ,
Publication No. 6, Sanitary Engineering Research
Laboratory, University of California, Berkeley (1953) .
3. Davids, H.W. , and Lieber, M. , "Underground Water
Contamination by Chromium Wastes," Water and Sewage
Works , Vol. 98, pp 528-534 (1951).
4. Geraghty & Miller, Inc. , Consultant* s Report, Port
Washington, Ne* York (1972) .
5. Harmond, B. , "Contamination of Groundwater Resources,"
H» P 343 (1941).
6. Lang, A., "Pollution of Water Supplies, Especially of
Underground Streams, by Chemical Wastes and by Garbage,"
Z-^Gesundheitstech^ &_Stadtehy.2- (Ger.) , Vol.24, No. 5,
p 174 (1932) .
7. Lang, A., and Gruns, H. , "On Pollution of Groundwater by
Chemicals," Ga^_ui_Wasjer, Vol. 83, No. 6; Abstract,
JOU£BSi_^IDSJiS3n__Water_Works_A^soca.atig5i/ Vol. 33, p
2075 (1940) .
8. McGauhey, P.M., and Krone, R.E., Soil Mantle as a
Wastewater Treatment System, Final Report SERL Report
No. 67-11, Sanitary Engineering Research Laboratory,
University of California, Berkely (1967) .
9. McGauhey, P.H. and Winneberger, J.H. , Causes and
H-E^ZSHtion 2J failure of Septic-Tank Percolation
Systems, Technical Studies Report, FHA No. 533, Federal
Housing Administration, Washington, D.C. (1964).
10, Muller, J. , "Contamination of Groundwater Supplies by
Gasoline," Gas u. Wasser,Vol. 93, pp 205-209 (1952) .
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11. Perimutter, N.M., and Lieber, M., Dispersal of Plating
W§§^SS §nd Sewage Contaminants in Ground Water and
SU£f§ce Watery South Farmingdale-Massapegua Are a, Nassau
County, New York,U. S. G. S. , Water Supply Paper 1879-G,~"67
op (1970) .
12. Sayre, A.N., and Stringfield, V.T., "Artificial Recharge
of Groundwater Reservoirs," Journal of American^ Water
Works Association,Vol. 40, pp 1152-1158 (1948).
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SEPTIC SYSTEMS
Scope of the^Prgblem
Septic systems are used in every state in the Union, the
heaviest concentration being in suburban subdivisions
developed following World War II and in recreational lake
development. The predominant type of system is the
individual household septic tank. From data available from
the Public Health Service and the Federal Housing
Administration, it is estimated that 32 million people were
served by septic tanks in 1970. In addition to the total
subsurface percolation systems associated with these
installations, there are an unestimated number of summer
cabins. Forest Service campgrounds, and organized group
camps which depend upon subsurface disposal of waste water,
primarily during the summer season.
Although the septic tank with an associated subsurface per-
colation system is the most commonly used type of septic
system, raw sewage is still discharged directly from the
plumbing system of the house into cesspools dug in the
ground. The practice is no longer approved for new
installations. Nevertheless, they may be found in the
United States wherever soil conditions make the cesspool
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feasible. In New York State there are probably 100,000 or
more such installations. In less populous areas such as New
England, the Southwest, and the Northwest, cesspools are
known to exist. Several thousand such systems discharging
into lava tubes are still in use in Hawaii.
The relationship between a septic sytem and the quality of
nearby ground water is governed by the design and control of
the system.
The septic tank is a water-tight basin intended to separate
floating and settleable solids from the liquid fraction of
domestic sewage and to discharge this liquid, together with
its burden of dissolved and particulate solids, into the
biologically active zone of the soil mantle through a
subsurface percolation system. The discharge system may be a
tile field, a seepage bed, or an earth-covered sand filter.
In some instances, as in the vicinity of Sacramento,
California, where the soil is sandy and the water table far
below the surface, seepage pits are used. These are drilled
holes some 75 centimeters (30 inches) in diameter extending
down to a depth of 6 meters (25 feet) or more, and filled
with gravel surrounding a wooden center frame.
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In the cold Northern and Northeast regions of the United
States, tile fields are located below the frost line. This
places them below the biologically active zone of the soil.
In low lands, notably in the South, a high ground water
table makes it necessary to place the percolation system
above the normal ground level. Here a one meter (three
foot) deep, soil-covered sand bed is used. It discharges
back to standing water in the swamps or road drainage
ditches if it cannot percolate directly into the ground
water.
In a percolation system located in the biologically active
zone, biodegradable organic matter is stabilized by soil
bacteria, particulate matter is filtered out, and certain
ions (e.g., phosphate) are adsorbed on the soil. Liquid
passing through the active soil zone percolates downward
until it strikes an impervious stratum or joins the ground
water. In the growing season, a portion, or even all, of
the septic tank effluent may be discharged to the atmosphere
by evapotranspiration. Salts not incorporated in the plant
structure are left in the root zone to be redissolved and
carried downward by percolating water. Thus, the purpose of
the percolation system is to dispose of sewage effluents by
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utilizing the same natural phenomena which lead to the
accumulation of ground water.
If the percolation system is below the biologically active
zone of the soil, filtering and adsorption phenomena
predominate. Biodegradation in the system is confined to
the partial degradation of organics under anaerobic
conditions.
Environmental Congeguences
Two categories of environmental effects which bear upon
control measures may be identified:
• Those which lead to restrictions on the use of
septic systems.
• Those which are inherent in a properly designed and
well-functioning septic system in suitable soil.
Under the first category three situations may be identified.
Most common of these is the failure of percolation systems,
which creates a hazard to health and an unacceptable
nuisance as decomposing sewage effluent appears on the
surface of the ground.
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The second and more serious situation in the context of
ground water quality is direct discharge of untreated septic
tank or cesspool effluent into the ground water through
coarse gravel beds, fractured rock, solution channels, or
lava tubes. In some areas of the United States, a local
practice is to cut trenches directly in bedrock and then
shatter the rock with explosives to create drainage
channels. Hawaii was mentioned earlier as an area where
cesspools are dug into lava tubes. In all of these cases,
the ground water itself often carries for long distances
putrescible sewage solids, bacteria, viruses, tastes and
odors, with consequent danger to health and impairment of
the aesthetic acceptability of water.
The third situation is somewhat similar to the second. It
occurs when percolation systems are located below the
biologically active zone, which typically is only a meter or
so in depth. Such systems may be installed where the frost
line is deeper than the biologically active zone, or they
may simply be buried too deeply because of lack of
understanding of proper construction techniques. (Long
Island is perhaps the most publicized case where percolation
systems are commonly to be found below the biologically
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active soil zone.) In such a situation, biodegradation in
the system is confined to the partial degradation of
organics under anaerobic conditions; the physical phenomena
of filtering and adsorption remain effective, but soluble
products of partial breakdown of organic matter may enter
the ground water and move with it. Tastes and odors are
introduced, and the organic fraction, being biochemically
unstable, remains capable of supporting bacterial growth
when the ground water outcrops or is withdrawn through a
well.
It may be said that at best septic systems increase the
total dissolved mineral solids in ground water. At worst,
they may introduce bacteria, viruses, and degradable organic
compounds as well. The multiple-point nature of septic
system inputs tends to minimize the concentration of
pollutants in any unit of receiving ground water. In some
local situations the effect may not be measurable by normal
analytical tests. In other local situations such as Long
Island, New York, and Fresno, California, where numerous
septic systems are installed in a single subdivision, the
effect on local ground water has been readily detected.
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Control Methods
Control of the effects of septic systems on ground water
quality must be considered in three situations:
1) Septic tank installations are already in existence.
2) New septic tank systems are to be installed.
3) No practical alternative to the septic tank is
presently feasible.
Of these situations, the first is the most difficult to deal
with because design is beyond recall and degradation of
ground water may have already occurred, of course, if
system failure is involved, the situation is largely self-
curative. The inability of soils to transmit effluent to
aquifers results in its appearance on the land surface and,
if the subdivision involved is of any significant size, to
an early replacement by conventional sewerage. However, if
an existing system is functioning satisfactorily, its total
contribution of salts co the ground water can be computed
from an analysis of the water supply and the known
contribution of salts from domestic use. The actual
immediate effect of any installation large enough to produce
measurable results may be estimated by monitoring the top of
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the ground water body. The control program would then
involve mandatory monitoring and judgment of the
significance of the results by competent hydrogeologists.
Several control procedures are applicable, viz.,
• Require any existing subdivision subject to septic
system failure or observed by mandatory monitoring
to be damaging to ground water quality to enter
into sewerage districts with collection and
treatment facilities.
• Require householders to connect to a sewer as urban
development fills in the open land that once set
the subdivision apart from an urban center, or as
land development extends the populated area beyond
the initial subdivision.
• Prohibit the home regeneration of water softeners
where septic systems are used for waste disposal.
In a situation where new septic tank installations are
proposed, possible measures for control include:
• Require approval of the site and design by
competent hydrogeologists, soil scientists and
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engineers before septic systems are approved for
any proposed subdivision, recognizing that simple
percolation tests (USPHS, 1968) and standard codes
offer only inadequate criteria for the design of a
septic system.
Construct percolation systems by methods which do
not compact the infiltrative surface (McGauhey and
Winneberger, 1964), including:
-- No heavy equipment upon infiltrative surfaces.
—r- Trenching, boring, or excavating for
percolation systems only when soil moisture is
below smearing level.
Use cf trenching equipment which does not
compact trench sidewalks.
Use cf classified stone sizes in backfills to
produce "clogging in depth" (McGauhey and
Winneberger, 1964).
Utilize level bottom trenches with observation
well risers at each end of each tile line.
Operate septic systems effectively by:
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— Alternately loading and resting one-half the
percolation system; the cycle to be determined
by the onset of ponding in the system at the
observation well.
Where size of system makes it practicable,
loading the entire infiltrative surface of the
system at each cycle as uniformly and
sirrultaneously as possible by use of a dosing
siphon.
Inspecting and removing scum and grease from
septic tanks annually.
— Drawing off half of the sludge rather than
pumping out the entire contents of tanks.
• Use of zoning and other land management controls to
prevent septic system installations in unsuitable
soils (i.e., soils too impervious to accept
effluents, or too coarse or fractured to maintain a
biological and physical treatment system).
In situations where no practical alternative to septic
systems is presently feasible, the alternatives are to:
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1. Limit use of septic systems to the growing season
for vegetation.
2. Permit the use of septic tanks if soil is suitable,
and accept the consequences in terms of ground
water quality.
3. Permit use of septic systems but restrict the
materials which may be discharged to them,
specifically, by prohibiting the installation and
use of household water softening units which are
regenerated on the site.
4. Permit the use of septic tanks under specific
conditions.
The first alternative is applicable to such installations as
forest camps, summer cottages, and summer camps in remote
areas where evapctranspiration and plant growth consume most
of the water and nutrients. The subsequent pickup of salts
in the root zone is done by relatively large amounts of
meteoric water.
The second alternative is essentially necessary in the case
of isolated dwellings on relatively large plots of land
remote from any sewer.
146
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The fourth alternative is an appropriate control measure
where soil is suitable and good design and operating
procedures are followed. Specifically, it may require that
sewers be provided in the streets of a housing development
and that house owners abandon septic systems and connect to
the sewer when it is available. A 5- or 10-year maximum
permit to use septic tanks can be specified,
Assuming that unsatisfactory systems are to be controlled by
regulatory action or replaced as a result of failure,
monitoring procedures would be confined to analyses of
percolating waste water and of the receiving ground water,
and to requirement of permits and inspection for any
softener installations or other connections to the household
plumbing system.
Technologically, the use of Tensiometers for sampling
percolating water in both unsaturated and saturated flow
conditions is a well-established routine. Questions to be
answered in the case of a subdivision based on septic
systems are: who is to make the installations, where are
they to be located, and how continuously are they to be
147
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observed and replaced. The most likely method would be to
evaluate the percolate on the basis of an analysis of the
water supply, and of a seasonal analysis of percolate
obtained from a short-term field study in one or more septic
tank percolation fields. Fundamentally, this procedure
yields baseline data but is not in itself a monitoring
sytem. In general, the monitoring of septic system
percolate is probably an unnecessary and unrewarding
procedure.
If ground water receiving percolate from overlying septic
systems is to be monitored, it is desirable to sample both
at the water table and at greater depths. Bacteria,
although they should not be present as a result of
percolating sewage effluents, tend to concentrate in soil at
the water table. Greases and oils which might be discharged
by the householder also tend to float on the ground water.
Pragmatically, monitoring may prove to be necessary in order
to verify technological predictions that degradation of
groundwater quality will occur because of prolonged and
concentrated use of sf. tic systems. In Suffolk and Nassau
Counties on Long Island, measurements of the degradation of
148
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ground water quality were a major factor in making decisions
to install sewers and treatment plants. (Other factors also
enter into the decision, of course; for example, loss of
local recharge may cause lowering of the water table when
sewers collect effluent and discharge it to a stream or
coastal waters.)
149
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References
1. Bendixen, T.Vi., et al.. Study to Develop Practical
S^sign Criteria! for Seepage Pits as a Method of
D.isJ2°.5<|l of S§Eii£~Tank Effluent, Report to FHA, Robert
A. Taft Sanit.Eng. Center,~USPHS, Cincinnati (1962).
2. Coulter, J.E., et al., Study of Seepage Beds, Report to
FHA, Robert'ft. Taft Sanit. Eng. Center, USPHS,
Cincinnati (1960).
3. McGauhey, P.H., and Winneberger, J.H., Soil Mantle as a
Wastewater Treatment System, Finai Report, slRL Sept.
No. 6_T-_11X Sanitary Engineering Research Lab., Univ. of
California, Berkeley (1967).
4. McGauhey, P.H., and Winneberger, J.H., Causes and
H££¥§Biion of Failure Qf Septic-Tank Percolation
Systems, Tech. Studies Rept., FHA No. 533, Federal
Housing Administration, Washington, D.C. (1964).
5. Perlmutter, N.W., and Guerrera, A.A., "Detergents and
Associated Contaminants in Ground Water at Three Public-*
Supply Well Fields in Southwestern Suffolk County, Long
Island, New York," U. S. Geol. Survey, Water-Supglv^
£aper_2001-B, 22 pp (1970) .
6. Schmidt, D. E. , "Nitrate in Groundwater of the Fresno-
Clovis Metropolitan Area, California," Ground Water,
v.10, no., 1 pp. 50^64 (1972).
7. U. s. Public Health service, Quad-City Solid Wastes
EE23§ct - An Interim Report, July 1, 1966 to May 13,
1967, USPHS, Cincinnati (1968).
150
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LANDFILLS
The Matter of Definition
To evaluate the effects of land disposal of solid wastes in
the context of "landfills" it is necessary to recognize an
unfortunate lack of distinction between the properly
designed and constructed sanitary landfill and the variety
of operations that are properly classed as refuse dumps. A
landfill is herein defined as any land area dedicated or
abandoned to the deposit of urban solid waste regardless of
how it is operated or whether or not a subsurface excavation
is actually involved. A "sanitary landfill" is:
"A method of disposal of refuse on land without creating
nuisances or hazards to public health or safety, by
utilizing the principles of engineering to confine the
refuse to the smallest practical area, to reduce it to
the smallest practical volume, and to cover it with a
layer of earth at the conclusion of each day's operation
or at such mere frequent intervals as it may be
necessary."
Less than 10 percent of the refuse disposal sites in the
United States are operated within this accepted definition
of a sanitary landfill. Very few of those considered true
sanitary landfills were established in sites studied and
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selected for the special purposes of hazardous waste
disposal.
Urban, or municipal, solid waste is considered to include
household, commercial, and industrial wastes which the
public assumes responsibility for collecting. However,
commercial solid waste and industrial solid wastes, presently
collected and hauled privately, may be discharged into a
public landfill, along with municipal wastes and refuse
which the citizen himself delivers.
2 °D s eguence s
The potential hazard of landfills to ground water quality
via leachate is a function of the total amount of waste
generated, its areal distribution, the composition of the
waste itself, and the siting, design, and operation of the
fill. The U.S. Environmental Protection Agency estimated
that in 1969 urban solid waste totaled 225 million tons per
year, while industrial solid waste was about 100 million
tons. Various estimates of this total for 1972 are about
one ton per capita per year — almost 2.72 kilograms per
person per day. In 1970 there were some 16,000 authorized
land disposal sites, and perhaps 10 times that many
152
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unauthorized dumping grounds. Because wastes are generated
and disposed of where people are, the pattern of population
distribution gives a clue to the location and intensity of
landfill practice.
Typical values of components of solid wastes collected in
urban communities are shown in Table 13. From this Table it
may be concluded that slightly over 70 percent of domestic
refuse is biodegradable organic matter of which about three-
quarters (50 percent of total waste) is paper and wood. An
additional fraction ranging from 1 to 15 percent in the
Table involves materials which might include some leachate
solids such as ashes and certain soils. Studies made in
Berkeley, California, in 1952 and repeated for the same area
in 1967 verify this conclusion and show that the percentages
of individual components changed very little over the 15-
year period.
Data on the amount and composition of industrial solid
wastes and its disposal are less extensive. A survey
(Manufacturing Chemists Association, 1967) of 991 chemical
plants, of which 889 were production facilities is reported
in Table 14. It shows that 75 percent of waste solids were
153
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noncombustible process solids and that 71 percent of the
total was disposed of by landfill on company-owned property.
No data are at hand on the composition of these wastes but
it must be presumed that some fraction of the total was
leachable if conditions leading to leaching occurred.
Santa Los Louis-
Clara'1 Angeles^5 villec
Paper Products 50 41 60
Food Wastes 12 6 18
Garden Waste1- 9 21
Plastics 1 2
Cloth, Leather
Rags, Rubber 42 —
Wood 22-
Rocks, Dirt
Miscellaneous
Unclassified 7 12 3
Metals 869
Glass and
Ceramics 7 8 10
a. EPA, 1970; University of California
b. Bergman, 1972
c. EPA, 1970; University of Louisville
d. US Public Health Service, 1968
e. Bell, 1963
f. Niessen and Chanskey, 1970
Quad-
Cities Purdue 23 Madison National
N.J.d Univ.e Citiesf Wis.g Avg.
45 42 46 52 50
1 12 17 10 15
1 12 10 8 5
2 1 1 2 3J
5 2 4 4 2k
i 2 3 2
10 15 1 -- 7
98978
66 9 15 8
g. Ham, 1971
h. Salvato, et al, 1971
i. Total 3 categories « 23 percent
j. Includes rubber
k. Rubber included with plastics
Table 13 Components of domestic solid
waste (expressed as percentages
of total).
154
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Type of Waste
Process solids, non-combustible
Process solids, combustible
Containers, non-combustible
Containers, combustible
Fly ash from fuel combustion
Other, or unspecified
Disposal Method
Landfill on company property
Landfill away from company
property
Incineration, with heat recovery
Incineration, without heat recovery
Open dump burning
Contracted disposal
Other, or unspecified
Total Per Year
(Thousands of
Metric Tons)
7,624
520
58
152
1,440
423
10,217
7,318
472
83
210
99
1,476
559
10,217
Percent
Total
75
5
1
1
14
4
71
5
1
2
1
15
6
Table 14 Landfill disposal
of chemical process wastes.
155
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Leaching^of^Lan dfillg
Leaching of landfills with consequent degradation of
underlying ground water depends upon several factors.
These, together with measures for control were summarized in
1971 (Salvato, et al, 1971).
If a landfill is to produce leachate there must be some
source of water iroving through the fill material. Possible
sources include: (1) precipation, (2) moisture content of
refuse, (3) surface water infiltrating into the fill, (t)
percolating water entering the fill from adjacent land area,
or (5) ground water in contact with the fill. In any event,
leactiate is not produced in a landfill until at least some
significant portion of the fill material reaches field
capacity. To accomplish this U.ll cm of water per meter of
depth of fill is reported to be necessary. This value is
far in excess of that which might be produced from a typical
mixed refuse. Moisture in refuse is about 20 percent by
weight. Because of the high paper content and the
relatively inert material shown in the typical analyses.
Table 13, only a small amount of moisture is released by the
decomposition of the organic solids in refuse. A composite
sample of an average municipal refuse is shown in Table 15.
156
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Moisture
Cellulose, sugar, starch
Lipids
Protein - 6.25N
Other organics
Inerts
Percent
20.73
46.63
4.50
2.06
1.15
24.93
100.00
Table 15 Composition of
municipal refuse
To induce composting, a moisture content of 50 to 60 percent
is required, hence a fill in a very arid region having no
source of moisture except that cf urban refuse will
decompose very slowly and produce little if any leaqhate.
On the other hand, if a fill were made of fruits and
vegetables having 80 to 90 percent moisture, anaerobic
decomposition would proceed rapidly and leachate would be
produced. Thus, landfill is not recommended for cannery
wastes alone.
Percolating water entering a landfill from surrounding land
is not likely in a proper landfill. If other sources of
157
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water are excluded from a landfill by employing procedures
described in a later section, the production of leachate in
a well designed and managed landfill can be effectively
eliminated. A proper landfill not intersecting the water
table will not cause water quality impairment for either
domestic or irrigation use. Subsequent reports of test
borings around landfills dating back as far as 50 years in
England showed no evidence of ground water pollution as a
result of leaching. Similarly, no evidence was found in
Holland that past landfilling has been a source of pollution
of ground water. Evidence reported from Illinois and
Minnesota is that leaching did not contaminate ground water
in two major fills built within the aquifer itself.
Compaction of fill material, clogging of fill area walls and
balance of hydrostatic pressure cause ground water to flow
around the fill rather than through it.
Absence of leaching as an important problem is
characteristic of landfill sites engineered and constructed
in accord with best current technology. In this category
are most of the sanitary landfills comprising 8 percent of
the present land disposal situations, and presumably those
to be built in the future. The 75 percent of urban refuse
158
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placed in dumps, which in varying degrees are open to
external sources of water, are likely to produce leachate in
significant amounts. It is estimated that of 124 cm annual
rainfall in New York, 45 percent will infiltrate into an
unsealed and unprotected dump. At some seasons of the year
up to 75 percent of the infiltrated water may be returned to
the atmosphere by evapotranspiration. The remainder, and at
times all, cf the infiltrate will percolate through the
landfill. If the fill is in a subsurface excavation, this
percolate will mcve downward to the ground water at a rate
governed by the degree of clogging of the underlying and
surrounding soil. Clogging, however, may reduce
permeability at the infiltrative surface; it cannot be
assumed that the landfill will long discharge leachate at an
appreciable rate. It may tend to become essentially a basin
filled with saturated refuse and soil. Further rainfall
will then run off the fill surface without coming in contact
with refuse. However, if leachate is produced within a fill
and soil clogging controls its escape to the ground water, a
large fill area, even at a low rate of movement into the
underlying strata, could with time, discharge a significant
volume of leachate.
159
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A secondary leaching phenomenon associated with all types of
landfills not subjected to specific controls is the result
of COz generated in the fill being forced outward into the
surrounding soil. When picked up by percolating rain water,
this increases the aggressiveness of water to limestones and
dolomites and so increases the hardness of ground water. A
refuse of the composition shown in Table 15 is theoretically
capable of producing 0.169 cubic meters of CO^ per kilogram
of refuse (Anderson and Callinan, 1969). However, the
balance of nutrients, the moisture, and other environmental
factors are unlikely to exist over the time span necessary
for any such complete destruction of the carbonaceous
fraction of refuse.
Nature and Amount^cf Leachate
Data on the analysis of leachate vary widely. Much of it
comes from short-term lysimeter studies in which researchers
had to make special effects to saturate the refuse so as to
produce maximum leaching. Thereafter, experiments were
often terminated before the leaching rate reached an
equilibrium. Data on leachate from several sources are
summarized in Table 16.
160
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Table 16 indicates what many observers have reported: the
initial values of EOD and COD are always high. Studies of
operating landfills show constituents of leachate to
include:
COD 8,000 - 10,000 mg/1
BOD 2,500 mg/1
Iron 600 mg/1
Chloride 250 mg/1
Table 16 also shows hardness, alkalinity, and some ions to
be significantly increased. The California data also show
that continuous flew through one acre-foot of newly
deposited refuse might leach out during the first year
approximately:
Sodium plus potassium 1.36 tons
Calcium plus magnesium 0.9 tons
Chloride 0.83 tons
Sulfate 0.21 tons
Bicarbonates 3.54 tons
161
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Determination (mg/£)
pH
Total hardness (CaCCb)
Iron total
Sodium
Potassium
Sulfate
Chloride
Nitrate
Alkalinity as CaCCb
Ammonia nitrogen
Organic nitrogen
COD
BOD
Total dissolved solids
a. No age of fill specified
5 is from 3-year old fill
b. Data from Los Angeles
c. Data from Emrich and
lb
5.6
8,120
305
1,805
1,860
630
2,240
no result
8,100
815
550
no result
32,400
no result
for Sources 1-3, Source 4
, 6 is from 15-year old fil
County (1968).
Landon(1969).
2b
5.9
3,260
336
350
655
1,220
no result
5
1,710
141
152
7,130
7,050
9,190
is initial
Sourcea
3b 4c
8.3
537
219 1,000
600
no result
99
300 2,000
18
1,290
no result
no result
no result 750,000
no result 720,000
2,000
leachate composition,
5C 6C
8,700 500
940 24
1,000 220
11,254 2,075
Table 16 Leachate composition
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Rates for subsequent years were expected to be greatly
reduced.
Field studies of the amount and quality of leachate through
well-designed fills have been made by the Los Angeles County
Sanitation Districts. At their Mission Canyon Landfill,
underdrains were installed beneath two large fills to entrap
leachate. One was installed in 1963; the other in 1968. At
the time of Meichtry's report (1971) the first of these two
had produced nothing but odorous gases although the fill was
heavily irrigated from 1968 onward. The second, deeper fill
produced odorous gases but no leachate until March 1968 when
11 cm of rain fell in 2U hours. On that occasion 806.1
liters of leachate were collected. Flow then continued at a
rate of about 5678 liters per month. Periodic analysis of
the leachate indicated that a spring in the canyon wall
beneath the fill, rather than infiltration of the fill, was
the source.
Table 17 shows both the initial composition of the leachate
and its reduction with time over a 3-year period. The Table
shows a decrease in concentration of most constituents of
the leachate with time. This same phenomenon has been
163
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observed in comparing a 21-year old abandoned fill with an
active fill.
Pilot studies were made in 1964 to 1966 to study the effects
of rainfall and irrigation on landfill leaching. Two cells,
15 meters square at the bottom and sloped to the top, were
filled with a single 5.3 meter lift of refuse, plus a 61 cm
earth cover. Devices to collect leachate at various depths
were installed. Cne was subjected to simulated rainfall,
the other to irrigation of turf. After 27 months and 330 cm
of rainfall, no leachate appeared in the rainfall cell, A.
small amount of water appeared in the topmost cell of the
irrigated system at 27 months and 429 cm of applied water.
164
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Constituent
PH
Total Solids, mg/£
Suspended Solids, mg/6
Dissolved Solids, mg/fi
Total Hardness, mg/C CaCO^
Calcium, mg/C CaCO^
Magnesium, mg/£ CaC03
Total Alkalinity, mg/£ CaCO3
Ammonia, mg/£ N
Organic Nitrogen, mg/£ N
BOD, mg/5 O
COD, mg/C O
Sulfate, mg/C 804
Total Phosphate, mg/£ PO4
Chloride, mg/8 Cl
Sodium, mg/£ Na
Potassium, mg/C K
Boron, mg/C B
Iron, mg/£ Fe
Leachate Analysis
Mission
3-18-68
5.75
45,070
172
44,900
22,800
7,200
15,600
9,680
0.0
104
10,900
76,800
1,190
0.24
660
767
68
1.49
2,820
Canyon Landfill
3-24-71
7.40
13,629
220
13,409
8,930
216
8,714
8,677
270
92.4
908
3,042
19
0.65
2,355
1,160
440
3.76
4.75
Table 17 Change in leachate
analysis with time (Meichtry, 1971)
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Limited experiments, such as the foregoing, support the
conclusion previously cited that leachate from well-designed
fills is not a significant problem.
The time required to produce leachate from a fill penetrated
by rainfall can be predicted by moisture-routing techniques
(Remson, 1968). For example, a 2.U4 meter lift of refuse
with 61 cm of earth cover will take from 1 to 2 1/2 years to
reach field capacity and produce leachate if 117.8 cm of
rainfall is allowed to infiltrate and percolate into the
fill.
In one field observation (Hassan, 1971) a landfill partly
inundated by ground water was investigated. Well water 325
meters down gradient from the fill showed leachate effects
in terms of hardness, alkalinity, Ca, Mg, Na, K, and Cl. At
a distance of 1,000 meters the effects were undetectable.
Inasmuch as the fill was an old one, it might be concluded
that the ground water was not seriously affected. However,
similar studies in Germany revealed the presence of leachate
effects in ground water 3,000 meters away.
166
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In the case of industrial wastes disposed of by landfill on
company property, little is known of the nature and extent
of leachate. Table 14 shows that noncombustible solids
represent 75 percent and ashes another 1U percent of the
total. These data suggest that soluble minerals provide the
most common materials which might be leached from industrial
waste fills. In terms of ground water pollution, oil,
process sludges, and salt solutions from lagoons and pits
are likely to be the most significant industrial wastes.
Control^Methgds
In general, procedures for the control of leachate are those
which exclude water from the landfill, prevent leachate from
percolating to ground water, or collect leachate and subject
it to biological treatment. Obviously, the possible
utilization of these three approaches is maximum in the
design phase of a landfill operation and minimal in some
types of existing landfills.
In existing situations the potential of a landfill to
pollute ground water can be limited by such procedures as:
• separating at the source wastes which are
unacceptable in a given landfill situation.
167
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• Controlling haulers by requiring permits and by
enforcing restrictions on materials for disposal,
• Licensing private haulers of industrial wastes.
In the case of a new projected landfill the control measures
include:
• Select site to achieve both general regulations and
specific objectives. Typical of the general
measures for siting control are those of Los
Angeles County which recognize three classes of
fills:
Class I, which may accept all types of solid
wastes by reason of its geologic isolation
from any contact with the ground water. This
type of site is essentially an impervious
bowl, and hence is not common.
" Class II, which may accept the normal run of
mixed municipal solid refuse (no waste oils,
or chemical sludges) .
- Class III, which may accept only inert earth-
type materials.
168
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Specific siting involves evaluation of alternate
locations by hydrogeologists and engineers to
determine such things as:
- Location and depth of ground water in the
vicinity.
Importance of underlying ground water as a
resource, both present and future.
Nature of geology of the site.
Feasibility of excluding both surface water
and ground water from the finished fill.
Design landfill to correct deficiencies of best
available site:
Use compacted earth fill to seal walls and
bottom of fill site. If the fill is above
water table, as is most commonly required,
this will minimize the rate of escape of
leachate from the fill. If the fill is in an
aquifer, the movement of the ground water into
and out of the fill will be minimized.
Provide underdrainage system to collect
leachate and deliver it to a sump.
169
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Drain sump to surface by a valved pipe or by a
vertical well into which a submersible pump
may be inserted, if necessary, to collect and
deliver leachate for biological treatment.
Construct fill with purpose of keeping the minimum
of refuse surface exposed to rainfall, and the
working surface and site well drained. Use dike
and fill technique to isolate fill from unfilled
area.
Utilize water for dust control during construction
in such amounts that evaporation rather than
infiltration is its fate.
Divert surface water from the fill site during and
after fill construction by means of peripheral
bypass drains.
Compact and slope fill cover for good surface
drainage, vent gases through the fill cover with J-
vents.
170
-------
In new or existing landfills:
• Provide continuing maintenance of the graded
finished fill cover, fill in and regrade surface as
shrinkage of the fill causes cracks or depressions
which might serve to increase infiltration.
• Seed completed fill surface with a high
transpiration cover crop.
• Avoid over irrigation of surface plantings.
• Divert both surface and ground water around fill
site where feasible.
• Reduce the amount of putrescible solid waste by
initiating regional reclamation activities under a
statewide authority which features energy
conversion of the organic fraction of refuse.
In the case cf existing landfills and dumps:
• Intercept polluted ground water at the fill site by
well points in or near the fill area if the
situation is serious.
• Initiate and implement statewide programs of waste
management which feature regional landfills, thus
replacing numerous small refuse dumps with
171
-------
landfills en an economic scale, phasing out with
time the leachate contribution to ground water.
Of the foregoing control measures only those which are
applicable to new sanitary landfills have the potential to
prevent or essentially to eliminate the possibility of
ground water pollution by leachate. Siting, constructing,
operating, and maintaining fills are in this category of
control measures. Existing well-engineered landfills,
although not generally equipped with underdrains, are
minimal in their effects upon ground water quality and hence
of secondary importance in comparison with dumps. Similarly,
old landfills may have contributed the major portion of
their leachate already and are now of secondary importance.
Reshaping the soil surface and maintaining surface drainage
are measures which reduce the effect of leachate from
existing fills. The overall effect of dumps may be lessened
by a geographical distribution of the volume of wastes they
contain. Control measures such as well-point interception
reduce rather than prevent or eliminate leachate discharges.
Regionalization of waste treatment is a control measure
which can reduce and eventually phase out the leachate from
existing dumps.
172
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Monitoring Procedures
In new fills, properly engineered and sealed off from
underlying and sidewall strata, the drainage system and a
pumped well located in or near the fill can be used both for
inspection (monitoring) and for control.
A system of three observation wells is illustrated in Table
18 along with the results of ground water quality
observations.
Groundwater
Characteristics
Total Dissolved
Solids
pH
COD
Total Hardness
Sodium
Chloride
Background
(mg/liter)
636
7.2
20
570
30
18
Fill
(mg/liter)
6712
6.7
1863
4960
806
1710
Monitor Well
(mg/liter)
1506
7.3
71
820
316
248
Table 18 Ground water quality
173
-------
It would be feasible to drill and gravel pack a sampling
well in a landfill, then seal its bottom and drill through
to the ground water below. Portable submersible pumps could
be used to pump these two essentially concentric wells for
sampling purposes. An alternative might be to drill a
pumped monitoring well downstream from the landfill or
directly through the fill. Concentrations of TDS, hardness,
and chlorides could be measured and used to surmise the
presence of leachate, provided the discharge rate needed to
produce a significant drawdown cone under the fill did not
obscure the effect of leachate on the ground water quality.
In any event the best procedure is the use of control
measures which minimize the possibility of leaching of
landfills.
174
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References
1. Anderson, D.R., and Callinan, J.P., Gas Generation and
Movement in Landfills, paper (1969) .
2. Anon. , "Sanitary Landfills: The Latest Thinking," Civil
Ingineer. ing , Vcl. 43, No. 3, pp 69-71 (1973) .
3. Bergman, R.D., "Urgent Need to Recycle Solid Wastes?,"
Civil Engineering, Vol. 42, No. 9 (1972).
4. Bell, J.M., "Characteristics of Municipal Refuse,"
of ttotional Conference OQ Solj.d Wastes
American Public Works Association Research
Foundation, Chicago (1963) .
5. Burch, L. A. , "Solid Waste Disposal and Its Effect on
Water Quality", Vector View^, Vol. 16, No. 11 (1969).
6. California State Water Pollution Board, Report on.
iGY^stigation 2£ I^SShi23 2% a SaniiSO Landfill,
Publication No. 10, Sacramento, California (1954) .
7. Dall, Frank R. , "The Effect of Solid Waste Landfills on
Groundwater Quality," Sixth Biennial Conference on
SESuncl Water Recharge^ Development Management,
University of California, Berkeley (1967) . """
8. Emrich, G.H,, and Landon, R.A., "Generation of Leachate
from Landfills and Its Subsurface Movement," Annual
Northeastern Regional An ti.- Pollution Conference
University of Bhode Island, Kingston (1969) .
,
9. Environmental Protection Agency, "A Citizen's Solid
Waste Management Project", Mission 5000, EPA (1972)
175
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10. Environmental Protection Agency, Cpmprehensive Studies
2£ Solid Waste Managementx First and second Annual
gepgrt§7 U.S. Public Public Health Service, Publication
No. 2039, Research Grant EC-00260, University of
California (1970).
11. Environmental Protection Agency, Solid Wastes Disposal
S&idv.' YQi- Ir J§fJj£Spn County., Kentucky; Institute of
Industrial Research,, University of Louisville, U.S.
Department of Health, Education, and Welfare, Bureau of
Solid Waste Management (1970).
12. Golueke, C.G., and McGauhey, P.H., Comprehensive Studies
of Solid Waste Management, First Annual Report7~SERL
Report No. 67-7, Sanitary Engineering Research
Laboratory, University of California, (Berkeley 1967).
13. Ham, R.K., personal communication. University of
Wisconsin (1971).
14. Hassan, A.A., "Effects of Sanitary Landfills on Quality
of Groundwater — General Background and Current Study,"
Paper presented at Los Angeles Forum on Solid Waste
Management (1971) .
15. Hughes, G.M., et alr Hy.drogeoloc[y. of Solid Waste
Disposal Sites in Northeastern Illinois, Progjrejfs Regprt
DQirQQOOj6, UjS. Department of Health, Education, and
Welfare (1968) .
16. Kaiser, E.R., "Chem-ical Analysis of Refuse Components,"
Ergceedings 1266 Incinjeratqr Conference, American
Society of Mechanical Engineers, New York, New York
(1966) .
176
-------
17. Los Angeles County, Development of Construction on Usg
Criteria for Sanitary Landfills, USPHS~Grant~No.^DOl-Ul-
00046, County^of Los Angeles, California (1968).
18, Manufacturing Chemists Association, "Most Solid Wastes
from Chemical Processes Used as Landfill on Company
Property," Currents (1967).
19. Meichtry, T.M., "Leachate Control Systems," Paper
presented at Los Ancjeles Forum on Solid Waste Management
(1971) .
20. Merz, R.C., and Stone, R.r Progress Report on Study of
Percolation Through a Landfall, USPHS Research Grant SW
00028-07 (1967) .
21. McGauhey, P.H., and Krone, R.B. , Soil Mantle as a
Wastewater Treatment System, Final Report, SERL Report
No. 67-11, Sanitary Engineering Research Laboratory,
University of California, Berkely (1967).
22. McGauhey, P.H., and Winneberger, J.H., Causes and
Prevention of Failure of Septic^Tank Percolation"
Systems, Tech. Studies Report, FHA No. 533", Federal
Housing Administration, Washington, D.C. (1964).
23. LeGrand, H.E., "Systems for Evaluation of Contamination
Potential of Solid Waste Disposal Sites", American
Waterworks Association Journal, Vol.56, pp 959-974
(1964).
177
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SEWER LEAKAGE
Gravity sewers above the ground water table, and pressure
outfalls either above or below it, are common elements of the
domestic sewerage system of organized communities.
Seasonally, storm sewers involving underground conduits and
lined and unlined open channels carry runoff from paved and
unpaved land surfaces. Essentially all of these conduits
are sited to accomplish drainage objectives.
Many major sewer systems had their beginnings at least a
century ago and soire original sectors of these systems are
still in use. Over this long period, construction materials
and methods have changed profoundly as the total length of
sewers has grown to tens of thousands of kilometers. Joints
in many of the gravity sewer systems carrying domestic
sewage number from 621 to 1243 per kilometer. Joining
materials have ranged through the years from cement mortar
to asphaltic and similar special compounds, and to plastic O-
rings and heat- shrinkage joint covers.
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Causal Factors
The potential of a municipal sewage system to contaminate
ground water is both varied and variable. Conceptually, a
sewer is intended to be water-tight and thus to present no
hazard to ground water except when temporarily disrupted by
accident. In reality, however, leakage is a common
occurrence, especially from older sewers. Leakage in
gravity sewers may result from causes such as:
• Poor workmanship, especially at the time mortar was
applied by hand as a joining material,
• Cracked or defective pipe sections incorporated in
the sewer,
• Breakage of pipe and joining material by tree roots
penetrating or heaving the sewer line,
• Displacement or rupture of pipeline by superimposed
loads, heavy equipment, or earthfill on pipe laid
on a pocr foundation,
• Rupture of pipe joints or pipe sections by slippage
of soil in hilly topography,
• Fracture and displacement of pipe by seismic
activity; e.g., a sewerage system in California,
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still suffers from fractures caused by an
earthquake in 1909,
• Loss of foundation support due to underground
washout,
• Poorly constructed manholes or shearing of pipe at
manholes due to differential settlement,
• Infiltration surcharging the system and causing
sewage to back up into abandoned sewer laterals.
Environmental consequences
Except at times of heavy infiltration during storms, which
may surcharge a system, the piezcmetric pressure inside a
gravity sewer laid above ground water is small. The static
head may vary from a maximum equal to the pipe diameter to a
minimum of perhaps 20 percent of that diameter.
Consequently, the rate of leakage accompanying several of
the cited failures is quite small. In fact, some small
leaks become stopped through closing of the opening by
suspended solids. Major fractures may release an
appreciable amount of sewage which moves along the pipe
foundation as the soil clogs, causing the trench locally to
function like the percolation system of a septic tank.
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Material escaping from a sewer via leakage is raw sewage,
which may be actively decomposing, together with such
industrial waste chemicals as may be present in the sewer.
Thus, if a sewer is deep underground and close to the ground
water, pollutants may be released below the biologically
active zone of the soil and so introduce into the receiving
ground water BOD and COD as well as chlorides and unstable
organics productive of tastes and odors. Because this
tendency is partly offset by the clogging of soils under
anaerobic conditions, the true effect of sewer leakage on
ground water quality is probably far less than the
theoretical potential.
If a fractured sewer is below the water table, infiltration
rather than leakage is the result. If infiltration is
seasonal and leakage occurs part of the year, the effect of
the intermittent flow may be to unclog the system and so
maintain a higher seasonal leakage rate than that of year-
round leakage.
Pressured outfall sewers are normally made of cast iron,
steel, transite, or concrete pipe. Except in very large
diameters they have fewer joints per mile than gravity
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sewers, and the joining is less likely to be of poor quality
or so readily ruptured. Because of superior construction
and engineering attention, the outfall sewer is not often a
threat to ground water quality. Due to the internal
pressure when leakage does occur, it is normally outward
regardless of whether the pipe is above or below the water
table. Small openings may clog,but most commonly sewage is
injected into soil cr ground water directly. It may appear
on the surface of the soil or outcrop on a hillside where it
is easily detected by sight and odor.
The effect of storm drains is generally to hasten the flow
of surface water to a surface stream. Therefore, it is
likely to have less potential than uncontrolled surface
runoff to spread the oils and soluble matter from streets,
fertilized land, and pesticide-treated gardens over
infiltrative surfaces feeding the ground water.
Looking to the future, it seems certain that sewer leakage
will be less of a hazard to ground water than at present,
even though the extent of sewer systems is certain to
increase to accommodate the growth and urbanization of
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population. The principal reasons are improved construction
and maintenance practices:
• Both new sewers and replaced old lines are laid
with joining materials which are water-tight and
also permit some change in pipe alignment without
fracturing.
• Better construction methods are practiced by
contractors.
• More rigid specifications and better inspection
characterize the larger units of government now
responsible for sewerage.
• Equipment for photographing or televising the
interior of a pipeline is available and
increasingly used to locate leaks and fractures in
a sewer system,
• Muncipal public works departments, using their own
personal or private contractors, are increasingly
and systematically surveying the condition of
sewers within their jurisdictions in a "search and
destroy" program of sewer repair and maintenance.
• Sewer maintenance has become a special division of
public works departments, and both the Water
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Pollution Control Federation and its member
societies conduct annual short courses and training
programs in the technology of maintaining sewers.
Control_Met.hods
Procedures for controlling the potential of sewer leakage to
degrade ground waters are implicit in the improved practices
listed above. The sewerage system of a large community is
an infinite point system of possible leaks. Moreover, the
system is underground and hence not subject to control by
surface observation and repair. Therefore, the most
productive control program has the following features:
• A public policy of maximum protection of ground
water as a part of an overall concern for resource
conservation,
• An organized and identified responsibility for
sewer construction and maintenance in the community,,
• Formulation and modernization of codes and
specifications for sewer construction as a state,
rather than a city responsibility, together with
appropriate inspection procedures,
• A program of internal and external inspection of
existing sewers at five-year intervals to detect
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and repair major leaks or to replace unrepairable
sectors of the sewer system,
• Emphasis en training of sewer maintenance personnel,
• Exclusion from discharge to municipal sewers of any
materials found to be irretrievably hazardous to
ground water.
Monitoring^Procedures
As in the case of lagoons, basins, and pits, monitoring of
ground water quality in relation to sewer leakage is best
accomplished by a program of collection and evaluation of
ground water data in each metropolitan area. Similarly,
surveillance of the control procedures should be maintained
so as to prevent and to correct leakage.
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TANK AND PIPELINE LEAKAGE
Scope of thgt Problem
In the United States, underground storage and transmission of
a wide variety of fuels and chemicals is a common practice
for commercial, industrial, and individual uses.
Unfortunately, the pipes and tanks are subject to failures
from a wide variety of causes and the subsequent leakage
then becomes a source of contamination to local ground
waters. European countries also have experienced these
problems; their technical literature is well worth
consulting.
This section describes the nature and occurrence of tank and
pipeline leakage and summarizes the practices that have been
found effective in the control and abatement of ground water
pollution. Emphasis in this section is on petroleum
products because they constitute the majority of materials
stored or transmitted in subsurface excavations. Leakage of
petroleum and petroleum products from underground pipelines
and tanks may be much more pervasive than is generally
realized. This is particularly true for small installations
such as home fuel oil tanks and gasoline stations, where
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installation, inspection, and maintenance standards may be
low. In Maryland, where standardized investigative
procedures have been adopted, some 60 instances of ground
water pollution were reported in a single year from gasoline
stations. In northern Europe, where most homes are heated
by oil stored in subsurface tanks, oil pollution has become
a major threat tc ground water quality (Todd, 1973).
Radioactive_Wastes
Tanks of solid radioactive wastes often are buried in
underground pits, primarily as a means of storing them in a
shielding medium while the radioactivity decays. Five sites
for storing low-level wastes are used in the United States,
operating under license and regulated by the states in which
they are located: Pichland, Washington; Beatty, Nevada;
Sheffield, Illinois; West Valley, New York; and Morehead,
Kentucky. Under state regulations, the sites are designed
and operated so that no leakage should occur. To assure
that no leakage is occurring, the states require and perform
monitoring of surface water and ground water in the vicinity
of the sites as well as from sumps in the backfilled pits.
The high-level wastes are under Federal control and there
187
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has been some leakage from such facilities. The EPA is
reviewing both types of storage at this time.
History
In the United States the use of underground tanks and pipes
has been most heavy in the petroleum industry. Here their
use has expanded with the industry to the point where
pipelines are now the major mode of transportation for
liquids and gases within the continental United States. The
present and increasing emphasis on the aesthetic value of
burying utilities and other commercial or industrial
structures will undoubtedly increase the number of tanks and
pipes that will be placed in excavations. Because pipelines
are an economical means of shipping, there is an increasing
trend toward developing methods for pipelining solids such
as coal or ores by powdering the solids and mixing them with
water or oil to produce a pumpable slurry.
Leakage in the United Statgs
Underground storage tanks are used in the United States by
industries, by commercial establishments, and by individual
residences. Industrial use is predominantly for fuels, but
a wide range of ether chemicals are also stored in tanks.
188
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Commercial businesses and individual homeowners use
underground storage almost exclusively for fuel. The most
numerous underground storage tanks are those used by
gasoline stations and for fuel oil at residences. These
small tanks are usually coated with a protective paint or
corrosion resistant material, but they are frequently
subject to corrosion-induced leakage. The primary problem
associated with such tanks is the fact that their
installation and use are not usually well regulated. If any
regulation exists concerning such tanks, in most cases it is
a local regulation requiring that tank construction and
installation be satisfactory, but it is rare that any
follow-up or periodic checks are required to determine
whether or not leaks have developed. Because such tanks are
small and comparativley inexpensive, cathodic protection is
not required even when the tanks are buried in clay soils,
which are known to promote galvanic action.
Pipelines are used for transportation, for collection, and
for distribution. Transportation pipelines are used for a
wide number of chemicals including oil, gasr ammonia, coal,
and sulfur. Their heaviest use is for the transportation of
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petroleum products, natural gas, and waterr in that order.
The list of commodities lost by accidents during one year
from liquid interstate pipelines is shown in Table 19.
Many industries employ underground collection pipelines to
move process fluids and wastes in-plant or for storage or
shipment. In oil fields, collection pipelines are used to
bring crude oil from wells to tanks for separation of
brines, and for storage and shipment.
The only pipelines for which any program of leak prevention
and any requirements for decontamination exist are the
transportation pipelines, and all of these are not covered.
All interstate transportation pipelines and some intrastate
pipelines are regulated; on collection and distribution
pipelines there is no regulation other than that of the
initial installation. The purpose and intent of the
regulations that exist are for preventing the escape of
combustible, explosive, or toxic chemicals. Prevention of
ground water pollution has not heretofore been the primary
consideration. Because interstate piplines are a major
means of transportation, they are regulated by Federal
government agencies in the Department of Transportation.
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Because leaks of petroleum products can produce a fire or
explosion hazard, these regulated pipelines have been
required, for the past five years, to report leaks and
spills. An analysis of these reports has been made and is
summarized in Table 20. It should be noted that the
quantities reported represent only leakage associated with
interstate carrier systems. This means that local
collection and distribution systems, gas stations,
residential users, and even relatively large intrastate
carriers are not included. Therefore, it must be assumed
that the leakage reported covers considerably less than 100
percent of the total leakage in the country.
Environmental Consequences
Pipeline and tank leakage into the soil can have several
environmental consequences, depending upon the chemical
leaked. Oils and petroleum products in even trace
quantities will render potable water objectionable because
of taste, odor, and effects on vegetation.
In sufficiently high concentrations,the vapors of lighter
fractions of petroleum products, liquified petroleum gas,
and natural gas can seep into basements, excavations.
191
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tunnels, and other underground structures. These vapors
mixed with the air in the cavity constitute a severe
explosion or fire hazard in the presence of open flame or
sparks.
Commodity
Crude Oil
Gasoline
L. P. G.
Fuel Oil
Diesel Fuel
Condensate
Jet Fuel
Natural Gasoline
Anhydrous Ammonia
Kerosene
Alkylate
Total
No. of
Accidents
172
51
39
21
5
5
4
4
3
2
2
308
%of
Total
55.9
16.6
12.7
6.8
1.6
1.6
1.3
1.3
1.0
.6
.6
100.0
Loss
(kiloliters)
18,404
6,677
6,341
2,102
1,105
582
355
1,390
1,560
111
252
245,057
%of
Total
47.2
17.1
16.3
5.6
2.8
1.5
.9
3.6
4.0
.3
.7
100.0
Table 19 Summary of interstate liquid pipeline
accidents for 1971 (Office of Pipeline
Safety, 1972).
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Number of accidents - 300 to 500
Number of tons lost — 33,333 to 66,666
Value of property damage - $650,000 to $1,300,000
Number of deaths - 1 to 11
Number of injuries — 8 to 32
Major cause — Corrosion
Major commodity lost — Crude oil
Table 20 Range of annual pipeline leak losses
reported on DOT Form 7000-1 for the
period 1968 through 1971.
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Chemicals such as ammonia and other agricultural or
industrial chemicals can have toxic properties. For
example, ammonia will add to the nitrification of ground
water, while acids can change the pH of ground water which,
in turn, will accelerate the solution of soil solids and
heavy metals.
The leakage of water can produce undesirable effects if the
dissolved solids in the water introduce objectionable
hardness or if the water is a brine.
Causal Factors
The annual report of leakage of interstate pipelines appears
to be representative of the cause of leaks for all pipelines
and tanks. Table 21 is extracted from Office of Pipeline
Satety (1972) to show the relative frequency of causes.
Other causes that have been reported in other years but did
not occur in 1971 were floods and surges of fluid in the
pipeline. Examination of the Table indicates that the major
cause of leakage is corrosion, which attacks the lines both
externally and internally. The second greatest cause can be
found by aggregating those related to pipeline component,
equipment, personnel failure, or malfunction. The third
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greatest cause is line rupture as the result of accidents
caused by earth moving equipment. The remaining few causes
include vandalism (usually bullet holes in exposed sections
of pipe, tanks or valves), severe weather, lightning, floods,
earthquakes and forest fires.
Cause
Corrosio n-ex ternal
Equipment rupturing line
Defective pipe seam
Corrosion-internal
Incorrect operation by carrier personnel
Miscellaneous
Ruptured or leaking gasket
Ruptured or leaking seal
Defective repair weld
Unknown
Ruptured leaking or malfunction of valve
Rupture of previously damaged pipe
Malfunction of control or relief equipment
Cold weather
Defective girth weld
Threads stripped or broken
Pump packing failure
Vandalism
Lightning
Total
Number
102
67
31
22
22
12
7
6
6
6
5
4
3
3
3
3
2
2
2
308
Percent
33.1
21.8
10.1
7.1
7.1
3.8
2.3
2.0
2.0
2.0
1.6
1.3
1.0
1.0
1.0
1.0
0.6
0.6
0.6
100.0
Table 21 Frequency of causes of pipeline leaks
in 1971 (Office of Pipeline Safety, 1972)
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Pollution Movernent
Liquid leaked into an underground excavation can behave in
several ways, depending on the characteristics of the soil
and the depth below the leak of the saturated zone. The
statements below apply not only to oil but also to all
liquid pollutants emanating from underground tanks and
pipelines. If the leak is from a tank of limited horizontal
extent or from a pipeline in relatively permeable soil, the
liquid will remain in the vicinity of the leak and move
downward through the soil under the influence of gravity.
On the other hand, if the leak is from a pipeline in
relatively impermeable soil, the leak liquid will tend to
remain in the trench. In a sloping trench in impermeable
soil, the fluid will tend to move through the backfill in
the trench along the outside of the pipe in the direction of
the slope. As liquid moves downward through the soil under
the influence of gravity, it will coat the soil particles as
it advances. This process removes some liquid from the
downward moving material. If the quantity of liquid is
small enough, it may be immobilized by this process,'
however, the leaked liquid may not remain immobilized.
Subsequent rainfall may wash the pollutant from the soil
196
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particles and carry it further downward until it reaches the
saturated zone.
If the leakage is large enough to reach the saturated zone
before exhaustion, its path of movement will depend upon the
density and viscosity of the fluid and whether it is
miscible with water. Miscible liquids will dilute slowly
with distance and time. Subsequent rainfall will tend to
displace oil or ether low density fluids floating on the
water table, producing a contaminated mixture in the upper
part of the aquifer. Once in the saturated zone, a
pollutant will move downgradient.
Figure E shows a plan view of an actual situation involving
a large gasoline spill and indicates how the leakage is
apparently concentrated in a depression in the water table
created by pumping wells.
It is quite possible for leaked liquids to move laterally
for great distances above the saturated zone. If a spill is
large enough, or if a leak continues long enough, the fluid
can migrate along impermeable layers above the water table
197
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and the same can happen along a pipeline, as described
earlier, until it reaches a permeable region where it can
move downward.
It should be noted that most chemicals do not move with the
velocity of ground water. Because of the effects of
sorption, varying iriscibility, solubility in water, and
varying chemical activity in the soils, chemicals usually
migrate through the soil in the direction of the ground
water flow but at a slower rate (Committee on Environmental
Affairs, 1972).
Contrgl^Methods
Most of the research and development on methods for
controlling and abating the contamination of ground water by
leakage from tanks and pipelines in underground excavations
has been concerned with reducing fire, explosion, and
toxicity hazards. Although it would appear that this work
is not often aimed toward abating pollution of ground water,
it may be applicable if judiciously applied. Many described
methods for handling hazardous materials can also be applied
to handling leakage materials such as sewage, brines, and
198
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agricultural and industrial chemicals net consic
hazardous.
STRONG TASTE
AND ODOR AREA
TEETx 100
PUMPING WELL
OBSERVATION WELL
Figure E Area contaminated by subsurface gasoline
leakage and ground water contours in the
vicinity of Forest Lawn Cemetery, Los Angeles
County, as of 1971 (Williams and Wilder,
1971).
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-------
Prevention. Primary control methods emphasize three types
of leak prevention:
1) Corrosion-preventing coatings such as tar or
plastic used on the outside of tanks and pipelines,
2) Cathodic protection used to minimize corrosion
resulting from galvanic action (Dept. of
Transportation, 1969, 1970a),
3) Internal fiberglass linings, which do not
deteriorate, used for small tanks such as those
used for gasoline storage (Matis, 1971).
Containment. Storage sites can be designed to contain
leaked liquids so that they can be trapped and removed
before they get into the soil. These methods are almost
exclusively applied to tanks. Lined excavations are
sometimes used to enclose a subsurface tank with an
impermeable material such as clay, tar, or sealed concrete.
These are analogous to the dikes used for containment in
oil-tank farms.
200
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Another method has been used in Switzerland (Todd, 1973) for
containing liquids that are lighter than water, such as oil.
An underground dam is built around the tank. The dam is
designed to penetrate the water table to such a depth that
the full volume cf the tank could leak into the space inside
the dam, and the bottom of the pool of leaked fluid would be
well above the bottom of the dam.
In pipelines, containment can be accomplished by use of
automatic shutoff valves inserted in the pipe at intervals.
These valves are designed to close off any section of pipe
where a significant drop in line pressure occurs. This
method, like containment devices for tanks, tends to limit
the spread and the volume of the leak and thereby permit
easier cleanup. At the present time this form of protection
is required on interstate pipelines but not on most small
collection and distribution systems.
Abatement by removal of soil. If a leak is discovered and
is accessible soon after it occurs, perhaps the best method
for preventing ground water contamination is removal of the
contaminated soil. It is important that this method be
applied before rainfall occurs in the region. Normally,
201
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without the flushing action of rainfall, liquids move
downward very slowly.
Figure F indicates that from several hours to a day or more
may be available before leaked liquids reach depths beyond
those that would be reasonable for normal earth removal.
This slow migration downward is a characteristic not only of
leaks small enough that they will be exhausted to immobility
before they reach the saturated zone,but also of leaks large
enough to eventually reach the saturated zone. Thus, in
dealing with the large leaks that are associated with a
catastrophic failure, such as a tank or pipe rupture, it is
important to initiate cleanup procedures rapidly.
202
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OIL SATURATION IN %
g
z
I—H
ffi
£
CD
Q
1 -
2 M
3-
6 —
7-J
10
I
20
I
30
I
40
INITIAL
, 10 HOURS
L/
23 HOURS
S(0) = 50 %
S(10) = 8,5%
S(23) = 6,1%
S(72) = 4, 6%
• 72 HOURS
50
d -
d =
d =
0,59m
3,45m
4,80m
6,40m
Figure F Experimental results from Switzerland on the
distribution of oil in soil as a function
of time (Toddr 1973).
203
-------
After the soil has been removed, the problem of how to
dispose of it must be addressed. The most suitable method
for handling biodegradable materials, such as oil, and many
agricultural chemicals such as ammonia, is to spread the
contaminated soil in a thin layer, 20 centimeters or less in
thickness, and permit the natural aerobic soil bacteria to
degrade it. This is usually accomplished within six months.
If the liquid is not biodegradable, the soil must be removed
to an appropriate industrial waste treatment plant and
processed as an industrial waste.
It should be noted that earth removal can be an extensive
operation requiring more than simply digging a hole with a
bulldozer and hauling the soil away in a truck. In at least
one case in an urban area, such earth removal involved the
demolishing of buildings and excavation of an area of
approximately the size of a city block.
Abatement by pumping or ditching. In cases where the
pollutant has reached the water table but has not yet moved
a significant distance from the leakage site, a removal well
can be used. This method works best for water-soluble
chemicals and for materials that float on the water table;
204
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however, it can be expensive and time consuming. With
respect to soluble chemicals, the effect of pumping will be
to reverse the normal direction of movement away from the
site of the leak. With respect to oil, the drawdown cone
that the well produces will trap the oil. In the case of
oil, two pumping locations are often used—a deep pump inlet
to maintain the drawdown cone and a skimming pump with its
inlet floating on the surface to remove the oil (Figure G).
If the pollutant has moved so far downgradient that
recapture by use of a drawdown cone is infeasible, a ditch
placed across a shallow contaminated plume can be used to
capture the pollutant. Figures H and I illustrate this
method.
When the water table is far below the surface of the ground,
a row of pumping wells may be required. Placed across the
contaminated plume, their drawdown cones will merge,
producing a trench in the water table. The contaminant
cannot escape from the depression and with time will
gradually be removed by the wells. After the contaminated
water is removed, it must be processed as an industrial
wastewater before disposal to a sewage system or return to
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the aquifer. The appropriate technique will depend upon the
nature of the pollutant and upon available wastewater
treatment facilities.
>V? "oo^c?" o_'_ °re° fp n ^^l*g!c
=>i.. ~ ^ _« c^ &r?.a o o,
Perforated Casing ^^
Figure G Swedish two-pump method for
removal of oil pollution from
a well (Todd, 1973).
206
-------
Spill Area
Impermeable
Barrier
^•••••v--ff«-4qaa
WateFJ.ffe;&:-:.^^^
'•"&•:'•••:•:'• JU^V'-'-v'-v"/'' .'.V-:-:-::-')Y-aler Movement :,i^^^.\;:V.y;V;'.^
Cross Section
Figure H Oil moving with shallow ground water
is intercepted by a ditch constructed
across migration path (Comm. on
Environmental Affairs, 1972).
Al
Line Of Section
Fig.2-B
Water Movement
Plan View
207
-------
Support
Rod
U
!
To Suction
Power
Supply
$m&y®
Support
Cable
Discharge
Line
B Submersible
Electric Pump
A Flotation Device May Be Substituted
For The Handling Cable Or Rod.
Figure I Three systems for skimming oil from
a water surface in ditches or wells
(Comm. on Environmental Affairs, 1972)
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Abatement by biodegradation. A method currently under
investigation is that of subsurface biodegradation. Many
chemicals such as ammonia and petroleum products are
biodegradable by aerobic bacteria, but below the surface air
transfer is slow and the aerobic bacteria tend to consume
the oxygen. At the present time research is being conducted
to identify anaerobic bacteria that would also be capable of
such biodegradation.
Abatement by chemical action. The use of chemicals to cause
precipitation of pcllutants within the soil is being
investigated. Sc far as is known no experimental results
are available. Further research on such methods is
required.
Monitoring Procedureg
In general the mcnitoring required for the detection of
leaks from tanks and pipelines in excavations is
proportional to the quantity of chemicals handled.
In small installations such as the household fuel storage
tank, gasoline station storage tank, and local collection or
distribution system, local monitoring is probably not
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economically feasible. If local governments regulate such
operations at all, they do so by ordinances and codes
specifying the materials and methods of installation. The
most frequent occurrence of leaks from underground pipes and
tanks is from these small systems. Commonly, monitoring for
such leaks is by "discovery," when a nearby owner discovers
that his water well is contaminated. Other examples occur
when an owner or operator discovers that the chemical is
disappearing from his tank faster than he is using it, or
when, during the rainy season the water table rises above
the level of a leak in a tank, the owner or operator
discovers that the tank is supplying water (Gilmore, 1973).
Monitoring methods and procedures for interstate carriers
are under the control of the Office of Pipeline Safety. To
assure that interstate carrier monitoring and pipeline
operation are being done satisfactorily, the Office of
Pipeline Safety requires detailed reports of all leakage in
excess of 8000 liters of commodities from initiation of the
leak to the time of cessation.
Monitoring procedures have been developed and implemented by
interstate carriers, but they can be applied to any
underground tank or pipeline. Pipelines contain pressure-
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monitoring devices that automatically close valves to
isolate a section of pipe whenever a significant pressure
loss occurs. Regular checking of pipelines and tanks is
accomplished by throughput monitoring, periodic inspection,
and periodic pressure testing.
In all of these monitoring procedures emphasis has been on
hazard and on economics; in general, if the leak is so small
or so located that it constitutes no hazard (as defined by
the Office of Pipeline Safety), and the costs of repairing
the leaks are greater than the loss incurred by the leakage,
no attempt will te made to detect, locate, or repair the
leak.
Throughput monitoring. Throughput monitoring compares input
and output. This irethod will detect large leakage rates,
but small rates, comparable to the fluctuations in
difference between the input and output measurements
resulting from temperature cnanges, inaccuracies in the
measuring instruments, etc., will go undetected. Improved
instrumentation might permit the detection of such leaks,
but usually they are detected by periodic inspections and
pressure tests.
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Periodic inspection. Periodic inspection includes a visit
to the site and at least a visual inspection. Often, if
volatile chemicals are involved, a tube is inserted into the
soil and air samples are drawn through portable gas
detectors. The periodic inspection of pipelines usually
takes the form of a patrol on foot, by truck, or by
aircraft. In all cases the dominant method of detection is
visual. In addition to seeking direct evidence of pipeline
leaks,inspectors are adept at identifying leaks by their
effects on adjoining vegetation.
For tanks in lined excavations, liquid level sensors or
vapor sensors (fcr volatile fluids) can be placed in the
space between the lining of the excavation and the tank.
These are connected to an alarm located where personnel are
on duty.
Pressure tests. Pressure tests are usually made on both
pipelines and tanks after repairs and periodically whenever
corrosion may be a problem. A tank or a section of pipeline
is filled and pressurized and the pressure monitored.
Allowance is made for temperature change and expansion under
pressure and the degree of leakage, if any, is determined.
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The normal pressure-test duration is 24 hours. A report
must be filed with the operator and the office of Pipeline
Safety.
This type of test is more sensitive than throughput
monitoring and periodic inspection, but because of the
potential variation of many parameters affecting the
pressure, small persistent leaks may go undetected and tests
may prove inconclusive. An example of the ambiguity of such
a test resulted at Forest Lawn Cemetery in Los Angeles
County. A pipeline near the cemetery was suspected as the
source of gasoline leakage, shown in Figure E. It was
pressure tested, but some experts said that the results
indicated that the pipe was tight, while others felt that
the results indicated a small leak. As of 1972, 189,000
liters of gasoline had been recovered at this site, and it
is estimated that the total spill amounted to 946,000
liters.
Monitoring solid radioactive wastes. The monitoring methods
used for tanks containing radioactive wastes buried in pits
include sampling from sumps, wells, and surface water.
Laboratory analyses are made for beta and gamma activity and
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tritium content. In practice, the methods are similar to
those for monitoring leachates from sanitary landfills.
214
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References
1. Atomic Energy Commission, "Category VITT -
Services," The Nuclear Industry, pp. 251-268 (1969).
2. Bureau of Surface Transportation Safety, A Systematic
ABE roach to Pit^JLine Safety, National Transportation
Safety Board,"ftashingtonT D. C, (1972).
Committee on Environmental Affairs, The Migration oj:
Products in SoiJ. and Ground Water—Princijo
Cojanterineasures, Publ.no. 4149, Amer, Petroleum
Inst, , Washington, D. C. , 36 pp. (1972).
<). Department of Transportation, "Title 49 -
Transportation," federal Register, v. 34, no. 191,
Washington, E> C. , 4 October (1969).
5. Department of Transportation, "Part 195—
Transportation," Federal Register, v. 35, no, (>2,
Washington, E.G., 31 March (1970),
6. Department of Transportation, "Title 49 —
Transportation," Federal Register, v. 35, no. 218,
Washington, D.C», 7 November ll97Oa).
7, Geraqhty, J.J. , "Movements of Contaminants" Water Well
Jour., v. 16, October (1961).
8. Gilmore, D., Personal Communication, March (1973).
9, Hepple, P. (Ed.), The Joint Problems of the oil and
Waiter Indu_strj.es, Proc. of a Symposium Held at the Motel
Metropole, Brighton, 18-20 January 1967, The Institute
of Petroleum, London, England (1967).
10. Jones, W.M.C., "Prevention of Water Pollution from Oil
Pipelines," Water Pollution by Oil, The Institute of
Petroleum, London, England (1971).
11. Laska, L., "Water Pollution Control in Alaska," Water,
Air, and Soil Pollution, D. Reidel Publishing Co. , *~
Dordrecht-Holland, pp. 415-432 (1972).
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12. Matis, J.R., "Petroleum Contamination of Groundwater in
Maryland," Ground Water, v. 9, no. 6, pp. 57-61 (1971).
13. McKee, J.E., et al. , "Gasoline in Groundwater," Jour._
Water Pollution Control Federation, v. 44, pp. 293-302
"(1972) ,
14. Office of Hazardous Materials, Summary of Liguid
J?i£§Ii,I,,£ Ac£i§,§Qts B§E2J£^ed on DOT Form 7000-1 from
3 $•££&£% I» i^i8 through December 31, 1968, Dept. of
Transportation, Washington, D. C. (1969)".
15. Office of Pipeline Safety, Summary of Liquid Pipeline
Accidents Reported on DOT Form 7000-1 from January 1^
1^70 through December 3_1, 1970, Dept. of Transportation,
Washington, cT C. (1971)".
16. Office of Pipeline Safety, Summary of LjLgu^.d Pipeline
Accidents Reported on DOT Form 7(H)0^1 Trom January 1,
JL2.Zi £ii£2iJ2li SSS^SlJb^E =li» J:5Zi» Dept. of Transportation,
Washington, C.~C. (1972).
17. Office of the Secretary of Transportation, "Title 49 -
Transportation", Federal Register, v. 35, no. 5,
Washington, C. C., 8 January (T970).
18. Office of the Secretary of Transportation, "Title 49 -
Transportation," Federal Register, v. 36, no. 86,
Washington, C. C. , 4~April (1971)"-
19. Office of the Secretary of Transportation, "Title 49 -
Transportation," Federal Register, v. 37, no. 180,
Washington, E. C., 15 September (1972).
20. Todd, O.K., Grcundwater Pollution in Euroge — A
Q2B£§£eQ5S Summary, GE73TMP-1, Seneral Electric Co.,
Santa Barbara, Calif., 79 pp. (1973).
21. Toms, R.G., "Prevention of Oil Pollution from Minor
Users," Water Pollution by Oil, The Institute of
Petroleum, London, England (1971).
22. Williams, D.E., and Wilder, D.G., "Gasoline Pollution of
a Groundwater Reservoir—a Case History," Ground Water,
v. 9, no. 6, pp. 50-56 (1971).
216
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23. Wood, L.A.r "Groundwater Degradation—Causes and Cures,"
Groundwater Duality and Treatment, Proc. of the 14th
Water Quality Conference, Univ. of Illinois, College of
Engineering, Urbana-Champaign, pp. 19-25 (1972).
217
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APPENDIX
ADMINISTRATOR'S DECISION STATEMENT NO. 5
SUBJECT: EPA POLICY ON SUBSURFACE EMPLACEMENT OF FLUIDS BY
WELL INJECTION
This ADS records the EPA's position on injection wells
and subsurface emplacement of fluids by well injection, and
supersedes the Federal Water Quality Administration's order
COM 5040.10 of October 15, 1970.
GOALS
The EPA Policy on Subsurface Emplacement of Fluids by
Well Injection is designed to:
1. Protect the subsurface from pollution or other
environmental hazards attributable to improper
injection or ill-sited injection wells.
2. Ensure that engineering and geological safeguards
adequate tc protect the integrity of the subsurface
environment are adhered to in the preliminary
investigation, design, construction, operation,
monitoring and abandonment phases of injection well
projects.
3. Encourage development of alternative means of
disposal which afford greater environmental
protection.
PR INCIP AL_ FINDIN G S_ AN D_^ POLI CY_ RATIONALE
The available evidence concerning injection wells and
subsurface emplacement of fluids indicates that:
1. The emplacement of fluids by subsurface injection
often is considered by government and private
agencies as an attractive mechanism for final
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disposal or storage owing to: (1) the diminishing
capabilities of surface waters to receive effluents
without violation of quality standards, and (2) the
apparent lower costs of this method of disposal or
storage over conventional and advanced waste
management techniques. Subsurface storage capacity
is a natural resource of considerable value and
like any other natural resource its use must be
conserved for maximal benefits to all people.
Improper injection of municipal or industrial
wastes or injection of other fluids for storage or
disposal to the subsurface environment could result
in serious pollution of water supplies or other
environmental hazards.
The effects of subsurface injection and the fate of
injected materials are uncertain with today's
knowledge and could result in serious pollution or
environmental damage requiring complex and costly
solutions on a long-term basis.
POLICY AND PROGRAM,, GUIDANCE
To ensure accomplishment of the subsurface protection
goals established above it is the policy of the
Environmental Protection Agency that:
The EPA will oppose emplacement of materials by
subsurface injection without strict controls and a
clear demonstration that such emplacement will not
interfere with present or potential use of the
subsurface environment, contaminate ground water
resources or otherwise damage the environment.
All proposals for subsurface injection should be
critically evaluated to determine that:
(a) All reasonable alternative measures have been
explored and found less satisfactory in terms of
environmental protection;
(b) Adequate preinjection tests have been made for
predicting the fate of materials injected;
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(c) There is conclusive technical evidence to
demonstrate that such injection will not interfere
with present or potential use of water resources
nor result in other environmental hazards;
(d) The subsurface injection system has been
designed and constructed to provide maximal
environmental protection;
(e) Provisions have been made for monitoring both
the injection operation arid the resulting effects
on the environment;
(f) Contingency plans that will obviate any
environmental degradation have been prepared to
cope with all well shut-ins or any well failures;
(g) Provision will be made for plugging injection
wells when abandoned and for monitoring plugs to
ensure their adequacy in providing continuous
environmental protection.
Where subsurface injection is practiced for waste
disposal, it will be recognized as a temporary
means of disposal until new technology becomes
available enabling more assured environmental
protection.
Where subsurface injection is practiced for
underground storage or for recycling of natural
fluids, it will be recognized that such practice
will cease or be modified when a hazard to natural
resources or the environment appears imminent.
The EPA will apply this policy to the extent of its
authorities in conducting all program activities,
including regulatory activities, research and
development, technical assistance to the States,
and the administration of the construction grants,
State program grants, and basin planning grants
programs and control of pollution at Federal
facilities in accordance with Executive Order
Signed 6 Feb. 1973
William D. Ruckelshaus
Administrator
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RECOMMENDED DATA REQUIREMENTS.. FOR. ENVIRONMENTAL F,VALUATION_
OF SUBSURFACE EMPLACEMENT OF FLUIDS _BY_WELL_INJECTION
The Administrator's Decision Statement Mo. 5 on
subsurface emplacement of fluids by well injection has been
prepared to establish the Agency* s position on the use of
this disposal and storage technique. To aid in
implementation of the policy a recommended data base for
environmental evaluation has been developed.
The following parameters describe the information which
should be provided by the injector and are designed to
provide regulatory agencies sufficient information to
evaluate the environmental acceptability of any proposed
well injection.
(a) An accurate plat showing location and surface
elevation of proposed injection well site, surface features,
property boundaries, and surface and mineral ownership at an
approved scale.
(b) Maps indicating location of water wells and all
other wells, mines or artificial penetrations, including but
not limited to oil and gas wells and exploratory or test
wells, showing depths, elevations and the deepest formation
penetrated within twice the calculated zone of influence of
the proposed project. Plugging and abandonment records for
all oil and gas tests, and water wells, should accompany thf:
map.
(c) Maps indicating vertical and lateral limits of
potable water supplies which would include both short-- and
long-term variations in surface water supplies and
subsurface aquifers containing water with less than 10,000
mg/1 total dissolved solids. Available amounts and present
and potential uses of these waters, as well as projections
of public water supply requirements must be considered.
(d) Descriptions of mineral resources present or
believed to be present in area of project and the effect of
this project on present or potential mineral resources in
the area.
(e) Maps and cross sections at approved scales
illustrating detailed geologic structure and a stratigraphic
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section (including formations, lithology, and physical
characteristics) for the local area, and generalized maps
and cross sections illustrating the regional geologic
setting of the project.
(f) Description of chemical, physical, and biological
properties and characteristics of the fluids to be injected.
(g) Potentiometric maps at approved scales and isopleth
intervals of the proposed injection horizon and of those
aquifers immediately above and below the injection horizon,
with copies of all drill-stem test charts, extrapolations,
and data used in compiling such maps.
(h) Description of the location and nature of present or
potentially useable minerals from the zone of influence.
(i) Volume, rate, and injection pressure of the fluid.
(j) The following geological and physical
characteristics cf, the injection interval and the overlying
and underlying impermeable barriers should be determined and
submitted:
(1) Thickness;
(2) areal extent;
(3) lithology;
(>4) grain mineralogy;
(5) type and mineralogy of matrix;
(6) clay content;
(7) clay mineralogy;
(8) effective porosity (including an explanation of
how determined);
(9) permeability (including an explanation of how
determined) ;
(10) coefficient of aquifer storage;
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(11) amount and extent of natural fracturing;
(12) location, extent, and effects of known or
suspected faulting indicating whether faults are
sealed, or fractured avenues for fluid movement;
(13) extent and effects of natural solution
channels;
(14) degree of fluid saturation;
(15) formation fluid chemistry (including local and
regional variations) ;
(16) temperature of formation (including an
explanation of how determined) ;
(17) formation and fluid pressure (including
original and modifications resulting from fluid
withdrawal or injection) ;
(18) fracturing gradients;
(19) diffusion and dispersion characteristics of
the waste and the formation fluid including effect
of gravity segregation;
(20) compatibility of injected waste with the
physical, chemical and biological characteristics
of the reservoir; and
(21) injectivity profiles.
(k) The following engineering data should be supplied:
(1) Diameter of hole and total depth of well;
(2) type, size, weight, and strength, of all
surface, intermediate, and injection casing
strings;
(3) specifications and proposed installation of
tubing and packers;
proposed cementing procedures and type of
cement;
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(5) proposed coring program;
(6) proposed formation testing program;
(7) proposed logging program;
(8) proposed artificial fracturing or stimulation
program;
(9) proposed injection procedure;
(10) plans of the surface and subsurface
construction details of the system including
engineering drawings and specifications of the
system (including but not limited to pumps, well
head construction, and casing depth);
(11) plans for monitoring including a multi-point
fluid pressure monitoring system constructed to
monitor pressures above as well as within the
injection zones; and description of annular fluid;
(12) expected changes in pressure, rate of native
fluid displacement by injected fluid, directions of
dispersion and zone affected by the project;
(13) contingency plans to cope with all shut-ins or
well failures in a manner that will obviate any
environmental degradation.
(1) Preparation of a report thoroughly investigating the
effects of the proposed subsurface injection well should be
a prerequisite for evaluation of a project. Such a
statement should include a thorough assessment of: 1) the
alternative disposal schemes in terms of maximum
environmental protection; 2) projection of fluid pressure
response with time both in the injection zones and overlying
formations, with particular attention to aquifers which may
be used for fresh water supplies in the future; and 3)
problems associated with possible chemical interactions
between injected wastes, formation fluids, and mineralogical
constituents.
SU.S GOVERNMENT PRINTING OFFICE 1973 -.-l.
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