SEPA
United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600/2-78-140a
August 1978
Research and Development
Land Cultivation
of Industrial Wastes
and Municipal
Solid Wastes
State-of-the Art
Study
Volume I
Technical Summary
and Literature,Review
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-78-140a
August 1978
LAND CULTIVATION OF INDUSTRIAL
WASTES AND MUNICIPAL SOLID WASTES
STATE-OF-THE-ART STUDY
Volume I
Technical Summary and
Literature Review
by
Tan Phung, Larry Barker,
David Ross, and David Bauer
SCS Engineers
Long Beach, California 90807
Contract No. 68-03-2435
Project Officer
Robert E. Landreth
Solid and Hazardous Research Waste Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Municipal Environmental
Research Laboratory, U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommen-
dation for use.
11
-------
FOREWORD
The Environmental Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health
and welfare of the American people. Noxious air, foul water, and spoiled
land are tragic testimony to the deterioration of our natural environment.
The complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.
Research and development is that necessary first step in problem solu-
tion and it involves defining the problem, measuring its impact, and search-
ing for solutions. The Municipal Environmental Research Laboratory develops
new and improved technology and systems for the prevention, treatment, and
management of wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and treatment of
public drinking water supplies, and to minimize the adverse economic, social,
health, and aesthetic effects of pollution. This publication is one of the
products of that research; a most vital communications link between the
researcher and the user community.
Soil has an enormous capability to assimilate waste materials. If
managed properly, soil can often serve as a sink for a wide range of waste
materials. Thus, land cultivation is truly a final disposal method where-
by the waste is recycled on land.
Francis T. Mayo
Director
Municipal Environmental Research
Laboratory
iii
-------
ABSTRACT
A literature review of published and unpublished data was
conducted to evaluate land cultivation of municipal refuse and
industrial wastes. Land cultivation is a process whereby waste
is spread and incorporated into the surface soil. This process
is viable only where soil, geology, waste characteristics,
climate, and other environmental conditions permit. Depending
on waste characteristics, land cultivation can be either coupled
with crop production or used solely as a disposal practice.
After incorporation into the soil, the waste is decomposed by
microbial metabolism and chemical processes, or is lost through
volatilization.
Land cultivation of municipal refuse has been limited due
to the large land area required, possible unsightliness, and the
lack of significant amounts of operational information. Land
cultivation of industrial wastes has been more widely practiced.
For instance, land treatment of wastewaters has been used by the
food processing industry. Three treatment systems are commonly
employed: slow infiltration, overland flow, and rapid infiltra-
tion. Grasses are grown to remove nutrients and water and to
facilitate infiltration. Land cultivation of sludges has also
been practiced by the food processing industry, and by refinery,
paper and pulp, pharmaceutical, and a few organic chemical
industries. Unless the waste to be deposited on land is con-
sidered either harmless or a nutrient source and soil amendment,
the disposal area is generally devoid of any purposely seeded
food crop. Most farm equipment may be suitable for use in the
land cultivation of industrial wastes.
Approximately 3 percent of all industrial wastes can be
disposed of by land cultivation. The waste loading rate is
generally limited by the soil physical properties (texture,
drainage, and permeability) and waste characteristics (pH, bulk
density, soluble salt and heavy metal contents, nitrogen and
phosphorus contents, etc.). Land cultivation costs range from
$2 to $18/m3 of industrial waste, excluding transport cost.
Existing state regulations generally call for consideration of
planned land cultivation projects on a case-by-case basis.
Documented environmental impacts of land cultivation
concern soil accumulation and plant uptake of heavy metals and
other waste constituents, surface and groundwater contamination,
and emanation of odors. These and other potential impacts are
iv
-------
ABSTRACT (continued)
«
controllable by improved operating techniques and effective
monitoring programs. In particular, routine monitoring of
surface soil can provide an early warning of fugitive contami-
nation. Also included are a site conceptual design and case
study summaries (detailed in Volume 2).
This report was submitted in fulfillment of Contract No.
68-03-2435 by SCS Engineers under the sponsorship of the U.S.
Environmental Protection Agency. This report covers the period
from July 1976 to January 1978, and work was completed as of
April 30, 1978.
-------
CONTENTS
Foreword iii
Abstract iv
Figures ix
Tables xi
Acknowledgments xiv
1 Introduction 1
Available Disposal Methods and Practices 1
Definition of Land Cultivation 2
History of Land Cultivation 3
Project Objectives and Scope 4
2 Summary and Recommendations 7
Project Findings and Conclusions 7
Operational Recommendations 9
Recommended Additional Research 10
3 Land Cultivation Practices ' 12
Land Cultivation of Municipal Solid Wastes 12
Land Cultivation of Industrial Wastewaters
and Sludges 16
4 Waste Characteristics and Quantities Related to
Land Cultivation 22
Waste Characteristics 31
Waste-Specific Disposal Considerations 36
Waste Quantities 36
>
5 Mechanisms of Waste Degradation and Volume Reduction. . 38
Microbial Degradation 38
Nonbiological Degradation 45
Evaporation and Volatilization 46
6 Effects of Waste Application on Soil Properties .... 48
Physical Properties 48
Chemical Properties 49
Microbiological Properties 51
7 Effects of Waste Application on Plant Growth and
Elemental Uptake 55
VI 1
-------
CONTENTS (continued)
Page
Municipal Solid Wastes 55
Industrial Wastewaters and Sludges 58
8 Regulations Affecting Land Cultivation 63
9 Site Selection Considerations 79
General Selection Criteria 79
Specific Selection Criteria 86
10 Site Operational Considerations 94
Waste Treatment 94
Equipment and Personnel Requirements 95
Waste Storage 109
Waste Loadings and Reappl ication 109
Soil Amendments 114
Soil Incorporation Processes 115
Management Considerations 116
11 Environmental Impact Assessment 121
Soil-Waste Interactions 121
Water Quality 124
Air Emissions 134
Health and Safety 136
12 Site Monitoring 148
Soil Monitoring 148
Runoff Monitoring 156
Vegetation Monitoring 157
Air Monitoring 159
13 Site Conceptual Design 160
Basis for Design 160
Site Design 164
Waste Application Procedures 166
Estimated Costs for Conceptual Land
Cultivation Site 169
14 Case Study Summaries 179
Land Cultivation Operations 179
Land Cultivation Economics 183
References 187
viii
-------
FIGURES
Number Page
1 Mechanisms of waste degradation 39
2 Persistence in soils of several classes of
insecticides and herbicides 44
3 Changes in C/N ratio and nitrate levels of soil
during microbial decomposition of a highly
carbonaceous waste material 53
4 Relative location of various landforms 83
5 Mixing tines of Bros rototiller 97
6 Bros mixing 97
7 Raygo mixing 98
8 Raygo mixing chamber 98
9 Koehring rototiller. , 99
10 Pettibone rototiller 99
11 Terra-gator sludge injector 101
12 Big Wheels sludge injector 101
13 I.M.E. sludge injector 102
14 Deep Six sludge injector 102
15 Refuse spreader from transfer truck 104
16 Terra-gator sludge spreader 104
17 Big Wheels sludge spreader 105
18 Big Wheels spreader with spray plate 105
IX
-------
FIGURES (continued)
i
Number Page_
19 Medium size tank truck capable of surface
spreading 106
20 Large tank truck with spray bar spreading
sludge on field 106
21 Example of disc tiller 107
22 Example of disc plow 107
23 Example of disc harrow 108
24 Reaction of wastes with soils 123
25 Artist's conception of land cultivation site . . . 163
26 Representative site profile 167
27 Runoff containment basin 174
28 Land cultivation annual unit costs 178
29 Case study and conceptual design unit costs of
liquid waste cultivation 185
-------
TABLES
Number . Page
1 Disposal Methods for Municipal Solid Waste
and Industrial Waste and Associated Drawbacks. ... 2
2 Matrix of Wastes Evaluated 5
3 Bulk Composition of Refuse (in percent) 13
4 A List of Selected Recent Conferences Pertinent
to Land Cultivation of Industrial Wastes 17
5 Selected Research Projects on Application of
Industrial Sludges to Agricultural Lands 20
6 Industrial Wastewater/Sludge Characteristics .... 23
7 Waste-Specific Land Cultivation Disposal
Considerations 26
8 Estimated Quantities of Industrial Wastewaters
and Sludges Suitable for Land Cultivation 28
9 Summary of State Regulations Affecting Land
Cultivation 64
10 Summary of Requirements for a Land Cultivation Site
in California 73
11 Summary of Texas and Oklahoma Land Cultivation
Guidelines 75
12 Soil Limitations for Accepting Nontoxic
Biodegradable Sludges and Solids 87
13 Classes of Permeability or Percolation Rates for
Saturated Subsoils 89
14 Soil Limitations for Accepting Nontoxic
Biodegradable Liquid Waste 90
15 Equipment Capability Matrix 96
XI
-------
TABLES (continued)
Number Page
16 Summary of Hydraulic and Organic Loading Rates
Used in Existing Land Application Systems
for Industrial Wastes ................ Ill
17 Comparative Characteristics of Low-Rate
Irrigation Overland Flow, and Infiltration
Percolation Systems ................. 113
18 Microbial Formation of Methylated Compounds ..... 123
19 Mobility of Selected Pesticides in Hagerstown
Silty Clay Loam Soil ................ 133
20 Plant Uptake and Translocation of Pesticides
from Soils ..................... 140
21 Possible Carcinogens in Man ............. 143
22 Carcinogens in Animals ............... 144
23 Selected Pollutants Which May Be Present in
Industrial Waste Streams and Residues ........ 149
24 Parameters to Be Monitored in Soil Prior to
and After Waste Application ............. 152
25 Response of Crops Grown in Soils of Varying
Salinity Levels ................... 153
26 Basis for Design .................. 162
27 Conceptual Design Waste and Site Parameters ..... 166
28 Labor Requirements for Conceptual Land
Cultivation Site .................. 169
29 Capital Costs for Conceptual Land Cultivation
Sites ........................ 171
30 Estimated Costs for Site Preparation and Closure . . 173
31 Storage Lagoon and Runoff Basin Dimensions ..... 175
32 Annual Capital and Operation and Maintenance
Costs for Land Cultivation ............. 176
XI 1
-------
TABLES (continued)
Number Page
33 Summary of Case Study Site Technical Information. . 180
34 Case Study Cost Summary 184
x i i i
-------
ACKNOWLEDGMENTS
The literature and case study reports are the result of
extensive cooperation between EPA, industry, university, and
SCS personnel. The guidance and assistance of Mr. Robert
Landreth, Project Officer, Municipal Environmental Research
Laboratory (MERL) of U.S. EPA, Cincinnati, Ohio, is gratefully
acknowledged.
We wish to express our appreciation to our consultants on
this project - Dr. Van Volk, Soil Science Department, Oregon
State University, Corvallis, Oregon; and Dr. Albert Page, Soil
and Environmental Sciences, University of California, Riverside,
California - for their assistance locating useful information
and review of several sections of Volume I. Assistance from the
personnel of the case study sites is also sincerely appreciated.
SCS project participants- were Mr. David E. Ross, Project
Director; Mr. Larry K. Barker, Project Manager; Dr. Hang-Tan
Phung, Soil Scientist; and Mr. David Bauer, Environmental
Scientist. Ms. Jackie Wittenberg edited the draft report and
checked the bibliography of the final version.
x i v
-------
SECTION 1
INTRODUCTION
The United States, with its large population and highly
industrialized economy, generates vast volumes of waste
annually. During the 4-yr period from 1970 to 1974, an esti-
mated 122 million t/yr (135 million tons/yr) wet weight of
municipal solid waste was produced. Industrial wastes were
estimated at an additional 237 million t/yr (260 million tons/yr}
dry weight during this same period (1).
Disposal of these wastes has become a major problem. Many
disposal techniques have been utilized or proposed, none of
which is problem free. Problem areas encountered have included
adverse environmental impacts, excessively high costs, and a
scarcity of acceptable sites. Existence of these problems has
led to a continuing search for new techniques to dispose of
specific waste types.
Land cultivation of municipal solid waste and industrial
sludges is a relatively new disposal method. It has been prac-
ticed with several industrial sludges and wastewaters in several
locations in the nation, and with municipal solid waste (refuse)
in at least three locations. Relatively little data is available
on land cultivation, as compared to many other disposal methods,
due primarily to its recent origin and limited practice. This
report describes a study to compile available data from diverse
sources and to develop new information about the practice of
land cultivation.
AVAILABLE DISPOSAL METHODS AND PRACTICES
Refuse and industrial wastes are primarily disposed of in
sanitary landfills, because landfilling usually has been the
least costly method of disposal acceptable to state and federal
environmental health agencies (2). However, there are currently
mounting tonnages of waste being produced, decreasing land
availability, higher land costs, and increasing public concern
over environmental issues.
Table 1 lists disposal methods and associated drawbacks for
municipal solid waste and industrial waste. It should be noted
that some of the disposal methods are used for temporary storage
or volume reduction; the residues left after such processing are
1
-------
TABLE 1. DISPOSAL METHODS FOR MUNICIPAL SOLID WASTE AND
INDUSTRIAL WASTE AND ASSOCIATED DRAWBACKS
Disposal Method
Sanitary landfill
Incineration
Pyrolysis
Composting
Discharge to sewers
Ocean dumping
Deep we!1 injection
Evaporation and
infiltration
Recycling
Cropland application
Land cultivation or
biodegradation
Significant Drawbacks
Leachate and methane gas production;
local lack of acceptable sites; long-
term commitment of land to disposal
purposes.
Costs and air pollution.
Unproven and costs.
Costs and low demand.
Treatment plant operational problems
and water pollution.
Potential adverse effects on marine
life.
Highly dependent on favorable
geologic conditions; water pollution
Air and water pollution.
New market development.
Limited wastes.
Water pollution; high land require-
ment.
generally buried in sanitary landfills. It is not unusual to
find combinations of these methods practiced in a disposal
process. For example, industrial sludges are often disposed
with refuse in a sanitary landfill. The selection of a specific
disposal method for any specific waste would be based upon the
characteristics of the waste, land availability, and economic
and environmental considerations.
DEFINITION OF LAND CULTIVATION
The term "land cultivation" as used throughout this report
is defined as a process whereby waste is mixed with or incor-
porated into the surface soil at a land disposal site. Other
terms which sometimes are used to describe the same basic
-------
practice are land farming, garbage farming, 1andspreading, land
application, land disposal, soil farming, and soil incorporation
The land cultivation process differs from other solid waste
disposal methods in that it is designed as a form of ultimate
disposal.
HISTORY OF LAND CULTIVATION
Spreading of organic wastes on agricultural land to supply
nutrients to crops is a practice dating far back in history. In
the Orient, "night soil" has been applied to cropland for
centuries. Farmers throughout the world have long utilized
livestock manure to fertilize fields. In addition, many nations
have been landspreading sewage for many years. These practices
are considered to be a form of land cultivation. However, in
these situations, the wastes commonly applied have been of
animal or human origin, not of industrial origin.
Evidence indicates that the oil industry was one of the
earliest practitioners of land cultivation of industrial sludges.
For example, land cultivation of oily wastes at one site in
California began in the 1950s.* Several major oil companies are
currently conducting full-scale or experimental land cultivation
operations. A major motivation for interest in this disposal
method is the high rate of microbial decomposition of the oil
under aerobic conditions. This allows relatively large quanti-
ties of oily waste to be applied to a given plot of land over
time. The same land can be reused for disposal of additional
waste. Thus, land cultivation often appears to be the most
economical disposal method available.
The food processing industry was another early user of
land cultivation. Organic wastes produced by this industry are
readily decomposed in the soil. Also, the wastes applied can
serve as a nutrient source and soil conditioner.
In recent years, several private firms - both manufacturers
and commercial waste disposal operations - have begun practicing
land cultivation. Cultivation of industrial sludges is often
initiated with a small-scale pilot project when the cost and/or
availability of alternative disposal methods force a reevalua-
tion of disposal methodology. If the pilot project proves
successful, the effort is generally expanded to cultivate all,
or much, of the generated waste. There has been a recent expan-
sion of the number of locations practicing land cultivation and
the types of industrial sludges involved. However, the growth
*SCS Engineers. Land Cultivation of Industrial Wastes and
Municipal Solid Wastes: State-of-the-Art Study, Vol. 2. EPA
68-03-2435. U.S. Environmental Protection Agency, Cincinnati,
Ohio, 1978.
-------
rate of land cultivation sites is relatively low, so that the
number of sites is still not large. Further, the types of
sludges cultivated continue to be primarily organic and non-
hazardous.
Land cultivation of municipal refuse is not widely prac-
ticed. The earliest large-scale operation was conducted in
Oregon (3) and has since been terminated. Field trials of land
cultivating waste paper were recently completed by the U.S.
Navy at Port Hueneme, California (4). Also, a small-scale
demonstration project sponsored by EPA is being conducted near
Houston (5). Only one large operation is being conducted - at
Odessa, Texas. The goal of the Odessa project, which began in
1975, is to combine refuse disposal with soil enrichment objec-
tives through application of the organic materials in the refuse.
In general, cultivation of refuse will probably be limited in
use due to a combination of factors: to be economically feas-
ible, land cultivation demands a large tract of marginal land,
which can be leased or puchased at low cost; the land must be
close to the refuse source; and the climate must allow nearly
year-round cultivation. Few localities offer such conditions.
PROJECT OBJECTIVES AND SCOPE
This project was conceived by the EPA as a state-of-the-art
review and assessment of land cultivation as a disposal method
for refuse and industrial wastewaters and sludges. A total of
nine major objectives were established:
t Gather and assess all available information relating to
past, existing, and planned land cultivation activities
Identify sites where land cultivation is being practiced,
and determine pertinent technical, operational, economic,
and environmental factors of five to six selected sites
Collect and analyze soil and vegetation samples at
seven operating sites
Evaluate the compatibility, feasibility, and environ-
mental safety of land cultivation for various waste
types
Characterize and quantify waste types potentially
suitable for land cultivation
t Review state regulations governing land cultivation
Prepare a site conceptual design
t Investigate the environmental effects of nonstandard
disposal of hazardous wastes
-------
Recommend needed future research and demonstration
projects.
Waste Types Evaluated
Specifically excluded from consideration during this study
are sewage sludge and all radioactive wastes. Little, if any,
industrial wastewater is land cultivated per se; therefore,
major emphasis was placed on industrial sludges and refuse.
Both organic and inorganic sludges were evaluated. Information
on the wastes studied is summarized in Table 2.
TABLE 2. MATRIX OF WASTES EVALUATED
Waste
Type
- --
No. of
Sites
Studied
Organic
Inorganic
Oily 3 X
Organic -,
chemicals
Tannery
Sulfuric
i
acid
Soap and
detergent
Pulp and
paper
Mixed
industrial
Muni ci pal
refuse
1
1
i
i
1
1
i
i
X
y
A
X
X
x
/\
X
X
X
x
/\
Data Sources
A variety of sources were utilized to obtain information
for this study. Much significant information was obtained from
papers published in the proceedings of conferences or symposia
on disposal of residues on land or land application of waste
materials. Computer search for published data from various
abstracts failed to provide sufficient information. A number of
technical journals provided a valuable source of information.
These included: Compost Science, Environmental Science and
-------
Technology, Journal of Environmental Quality, Residue Review,
Journal of Agricultural and Food Chemistry, Advances in
Agronomy, and Agronomy Journal. Other significant sources
included published books and governmental reports, and personal
interviews with state regulatory agency representatives, univer-
sity researchers, and site operators.
Project Duration
Activities were initiated in July 1976 and extended over an
18-mo period. Early effort was devoted to reviewing all avail-
able literature and contacting knowledgeable persons. Later,
site visits were conducted to obtain necessary information and,
in many cases, soil and vegetation samples.
-------
SECTION 2
SUMMARY AND RECOMMENDATIONS
A review of the available literature pertaining to the
disposal of industrial wastewater and sludge and municipal
solid waste (refuse) by land cultivation has been conducted.
This literature review was supplemented by field investigations
at ten operating sites in nine states across the nation.
Samples of soils and vegetation were collected at seven of the
sites to provide further insight into the effects of land
cultivating a variety of wastes.
Land cultivation is based on the aerobic microbial decompo-
sition of organic wastes in the surface soil. This disposal
practice may upgrade drastically disturbed lands and eliminate
gas and leachate problems generally associated with anaerobiosis
in sanitary landfills.
Nonstandard disposal of hazardous wastes was also investi-
gated, but in less detail than land cultivation. The thrust of
this effort was to identify nonstandard disposal techniques
currently in use and the associated hazardous wastes.
This section summarizes the work which is reported in
detail in later sections.
PROJECT FINDINGS AND CONCLUSIONS
Information obtained through the literature review, field
interviews with operating personnel, on-site observations, and
sampling and analysis allows several conclusions to be drawn
concerning land cultivation as a disposal technique. Briefly
summarized, these conclusions are:
1. Information about the operational, economic, and
environmental aspects of land cultivation of municipal
refuse and industrial sludge is limited. Published
literature primarily deals with the land application of
municipal sewage sludge and wastewater, and animal
manures, as well as the landfilling of municipal refuse
and hazardous wastes.
2. Major waste types currently being land cultivated are
sludge from oil refineries and wastewaters from the
-------
food processing and paper and pulp industries. The
chemical composition of these wastes may vary consid-
erably within the same industry. Waste characteristics
often are not adequately characterized with respect to
their environmental acceptability to be disposed by
this method before being cultivated.
Existing land application is, in many respects, similar
to farming operations. Experience and equipment used
in farming are often applicable to, but not necessarily
designed for, land cultivation.
The quantity of municipal solid waste cultivated is not
expected to increase significantly in the future due to
the sorting and shredding costs, and the scarcity and
cost of large tracts of land in close proximity of
major cities.
The quantity of cultivated industrial wastes should
increase with time due to stringent regulations on air
and water pollution control. The estimated quantities
of industrial wastewater and sludge suitable for land
cultivation in 1975, 1980, and 1985 are:
1975 1980 1985
Wastewater (106m3/yr) 735 840-920 940-1,160
Sludge (106 t/yr, dry wt.) 7.2-7.5 8.8-9.1 10.8-11.1
Only a limited number of industrial wastes are amenable
to land cultivation without treatment. With the
advancement of processes that remove or detoxify the
hazardous constituents of the waste products, the
waste types potentially suitable for land cultivation
will be increased.
Currently there are no official federal guidelines that
suggest the suitability of certain waste types for
land cultivation. The waste to be land cultivated is
usually evaluated based on the concentrations of
soluble salts (including sodium), heavy metals, and
toxic organics and elements. Application rates vary
with waste type, land availability, and climatic
conditions.
There have been no incidents of water pollution
reported at any of the studied sites. Heavy metals
and trace elements appear to be retained in the zone
of incorporation. Surface soils and plants collected
from sites receiving refinery wastes showed elevated
8
-------
concentrations of heavy metals (particularly lead,
zinc, manganese, and nickel).
9. The effect of land cultivation on the food chain is
not known, since those land cultivation sites studied
that receive wastes containing high concentrations of
hazardous constituents do not have agronomic or food
crops.
10. Improvements in equipment design are needed. The
cultivator used at Odessa, Texas, is subject to fre-
quent mechanical breakdown. Users of conventional
agricultural tank wagons for applying industrial sludge
also report repeated failures. One such operator
indicates that the tank wagons are his highest main-
tenance item.
11. Both capital and operating costs are dependent on local
conditions. The most significant causes of these cost
variations are labor rates and land costs.
12. Annual operating costs, which include amortized capital
costs, are subject to economies of scale. This is
most clearly indicated in the costs developed for the
site conceptual design (Section 13). The costs
obtained for five case study sites (Section 14) show
a similar trend, even with local, site specific,
differences. This data shows a range from $1.7/m3 to
$17.6/m , with input waste quantities of from 3,400 m3/
yr to 94,400 m3/yr.
13. Only Texas was found to have regulations specifically
formulated to apply to land cultivation of industrial
wastes. Most states deal with each application on a
case-by-case basis.
OPERATIONAL RECOMMENDATIONS
Four factors concerned with the operation and management
of a land cultivation site are recommended. These are:
1. Before cultivation activities are initiated, the waste
should be thoroughly characterized. The variability
in its chemical and physical properties should also
be determined.
2. Next, the suitability of the proposed site for receiv-
ing wastes should be determined. Various guides are
available for rating soils for receiving many kinds of
wastes. Groundwater quality and depth should be
evaluated, as should site topography and drainage
patterns and the proximity of surface water.
-------
3. An operational site must be properly managed. This
normally entails soil pH control (generally above 6.5
for most wastes), nutrient addition to promote micro-
bial decomposition, rational selection of waste loading
rates and tilling operations to maximize waste degra-
dation, and installation and maintenance of surface
and groundwater protection facilities.
4. The site must also be properly monitored to ensure that
waste constituents are retained in the layer of incor-
poration. This can be accomplished by collecting soil
samples at three depths (0 to 30, 30 to 60, and 60 to
90 cm) prior to site activation and at 3- to 6-mo
intervals thereafter. Soil samples collected should be
analyzed for those constituents present in the waste
which may result in water pollution problems. Ground-
water and nearby surface water should also be monitored
to determine effects of the disposal operation.
Depending on waste and site characteristics, it may be
desirable to establish a program to monitor local
air quality and runoff.
RECOMMENDED ADDITIONAL RESEARCH
Further research is recommended in several areas to more
adequately understand the processes involved in land cultiva-
tion. Particularly recommended is research into the following
subjects:
1. Techniques to promote waste decomposition such as
addition of nutrients and amendments; microbial seed-
ing; co-disposal of two or more waste types.
2. Characterization of the intermediate and final degra-
dation products from most industrial wastes to
determine the acceptability of a waste for land culti-
vation and the related monitoring requirements.
3. Retention mechanisms and factors influencing the form
and long-term behavior of metals in soils. This is
essential to development of better recommendations
and management techniques for application of high
metal wastes to soils.
4. Waste quality improvement by modifications of industrial
processes and other techniques such that the properties
that make some wastes unsuitable for land cultivation
can be removed.
5. Limits of soil loading of heavy metals, toxic organics,
and hazardous constituents on cropland and noncropland.
10
-------
6. Utilization of waste products as feeds, fertilizers
(macro- and micronutrients), soil amendments, construc-
tion materials, etc., and techniques to recover
elements and other constituents in the wastes.
7. Air quality at the land cultivation sites receiving
refinery wastes and mixed industrial waste, and in
areas where dust is often a problem.
8. Public attitudes toward land cultivation. This may be
improved through detailed and carefully organized
educational and information programs.
11
-------
SECTION 3
LAND CULTIVATION PRACTICES
LAND CULTIVATION OF MUNICIPAL SOLID WASTES
The average person in the United States discards wastes
amounting to 2.27 kg/day (5 Ib/day) (6). Hortenstine and
Rothwell (7) have estimated that 450 million t (495 million
tons) of municipal solid wastes must be handled yearly. For the
most part, paper is the major waste component, followed by
metals, glass, food, and garden and yard materials (Table 3).
In recent years, the paper content of municipal solid waste
has increased, largely because of more product packaging in the
prepared food industry (6).
Soil Incorporation of Municipal Solid Waste
Few research or demonstration projects have been concerned
with the application of municipal solid waste directly to soil
without prior sorting or shredding. The initial research study
by Hart et al. (11) incorporated coarsely ground, unsorted
municipal refuse into surface soil at Davis, California, at
rates of 112 to 896 t/ha (50 to 400 tons/ac) dry weight.
Nitrogen fertilizer was added to balance the C/N ratio of the
refuse, and the plots were kept moist. After 1 yr, an uniden-
tifiable organic residue remained in addition to glass, metal,
and plastic. No odor, insect, or rodent problems were reported,
but some blowing of plastic occurred. The second year, it wa.s
somewhat difficult to incorporate an additional 896 t/ha (400
tons/ac) of waste material into the soil, since the surface
layer consisted primarily of residue from the previous year's
waste application.
Municipal waste has been found to be most easily handled in
a land application system if it has first been finely shredded
(12). The shredded waste should be distributed evenly over the
land surface at rates that allow incorporation into the soil.
Data from a study conducted near Boardman, Oregon, suggest
that with conventional field tillage equipment, an application
rate of 448 t/ha (200 tons/ac) should not be exceeded (13, 14).
In this study, the unconsolidated refuse was approximately
60 cm (24 in) thick at an application rate of 896 t/ha (400
12
-------
TABLE 3 . BULK COMPOSITION OF REFUSE (IN PERCENT)
Component
Paper
Newsprint
Metals
Ferrous
Nonf errous
Glass
Plastics
Cloth, rubber, leather
Wood
Food waste
Yard and garden
Misc. and uncategorized
TOTAL
Cambridge,
Mass. *
35.8
(7.8)
9.2
(8.3)
(0.9)
18.6
4.1
5.2
1.1
5.9
0.5
19.6
100.0
Middl eburg »
Vermont *
48.9
(3.0)
9.1
(8.8)
(0.3)
16.6
2.4
2.5
0.4
4.7
0.3
15.1
100.0
Cal i form' a^
43.0
7.0
(6.0)
(1.0)
9.0
2.0
4.0
4.0
6.0
19.0
6.0
100.0
U.S.*
36.8
(7.2)
8.8
(7.8)
(1.0)
9.4
3.5
3.9
3.4
15.6
17.3
1.3
100.0
*From Winkler and Wilson (8).
"iTrom California State Solid Waste Management Board (9)
#From U.S. Environmental Protection Agency (13).
-------
tons/ac). After mechanical compaction and irrigation, the
refuse was reduced to a thickness of 20 cm (7.9 in). Little of
the sandy soil was mixed with the refuse when the refuse depth
exceeded 15 cm (6 in). During mixing, rags wound around the
rotovator, a problem that may be corrected by using other types
of mixing devices. All the studies indicate that the applica-
tion rates for shredded municipal waste depend upon waste
composition and plans for final land use.
King et al. (15) applied unsorted, shredded municipal
refuse and anaerobically digested sewage sludge to a Guelph loam
soil in Ontario, Canada, at rates of 188 and 376 t/ha (207 and
414 tons/ac) and 2.3 and 4.6 cm (0.9 and 1.8 in), respectively.
The refuse was first spread on the soil surface. A furrow was
then plowed about 30 cm deep into which most of the refuse
adjacent to the furrow was raked by hand. The next furrow was
then plowed to cover the refuse. This technique resulted in
good refuse coverage but concentrated a large part of the
refuse in the 15- to 30-cm depth. Refuse in the 0- to 10-cm
layer was well mixed with the soil by subsequent diskings, but
there was little mixing of refuse at lower depths. Following
this initial refuse application, sludge was applied, allowed
to dry, and then disked into the soil to a depth of 10 cm. It
was not possible to physically mix the sludge with the refuse
to achieve an optimal C/N ratio. However, the application
technique did place the sludge in an area of high root uptake
and the refuse at a low level, where nitrates from the sludge
moving downward could be immobilized or denitrified.
Stanford (5), under contract with EPA (OSW), has initiated
a 3-yr study near Houston on a multivariate trial. For the
study, shredded municipal refuse, dry sewage sludge, and chem-
ical fertilizer were added separately and together on the soil
surface. The effects of these additions on crop yield and
quality, soil quality, aird water quality will be assessed over
time. The shredded municipal refuse (80 percent £ 20 cm in
size) and dry sludge were applied to a sandy clay (pH 5.37) at
rates up to 560 t/ha (250 tons/ac) and 336 t/ha (150 t'ons/ac),
respectively. The wastes were incorporated into the soil by
rototilling with a heavy-duty soil stabilizer. Clover and
grasses were seeded. Initial observations showed marked
differences in growth due to waste application; high waste
application rates produced only sparse vegetation (Stanford,
personal communication).
The city of Odessa, Texas, is evaluating a program utiliz-
ing sewage sludge, septics, and shredded municipal refuse to
stimulate the growth of vegetation in the city's semi-arid
environment (Schnatterly, personal communication). Under this
soil enrichment program, shredded residential solid wastes were
spread at rates up to 278 t/ha (120 tons/ac) and were tilled
into a sandy loam soil with a soil stabilizer. Septics and
14
-------
sewage sludge were added to some plots prior to seeding with
grass. Preliminary observations indicate some equipment
operating problems. In addition, blowing of paper occurs
occasionally; however, odor is minimal.
During a Tri Service Project at the Navy Construction
Battalion headquarters, Pt. Hueneme, California (4), waste paper
consisting mostly of cardboard was shredded to three size
categories (0.6 to 3.81, 10.2 to 15.2, and 31 cm) and applied
at rates of 44.8 to 448 t/ha (20 to 200 tons/ac) to two soils
(sandy and clayey). The waste was incorporated into the surface
0 to 46 cm (0 to 18 in) by a soil stabilizer. Usually one pass
was sufficient. Researchers concluded that land cultivation of
the waste paper was not cost effective. This disposal method
was, therefore, not recommended for use by the Armed Services.
Soil Incorporation of Composted Municipal Solid Waste
Composted municipal refuse can be used to reclaim soil
material and to enhance plant growth in strip mine spoils,
mine tailings, various industrial deposits, and on agricultural
lands. Composting lowers the C/N ratio of the refuse, stabil-
izes the organic materials, and eliminates most of the health
hazards possibly associated with fresh refuse. If the compost
includes sewage sludge, it usually contains small but signifi-
cant amounts of nitrogen and phosphorus, which serve as
nutrients for soil microorganisms and higher plants. On the
other hand, it is speculated that plant uptake of heavy metals
may reach phytotoxic levels after continuous high rates of
sludge application (Duggan and Wiles, unpublished data). Con-
centrations of heavy metals in sewage sludge are dependent on
the type and number of local industries and the quantities of
their wastewaters discharged into the sewers (16).
Refuse compost was applied at 35 to 70 t/ha (16 to 31 tons/
ac) to sand tailings from phosphate mining at Bartow, Florida.
The compost added organic matter and plant nutrients to the
tailings, as shown by the growth of sorghum and oat crops on
the treated tailings (17). In another study, the growth of
young slash pine trees was neither positively nor negatively
affected by the application of Gainesville, Florida, refuse
compost at rates of up to 44 t/ha (19.6 tons/ac) (18). However,
aesthetics of the site were somewhat spoiled by the residue of
nondegradable particulates that persisted on the soil surface.
Researchers have applied refuse compost from Johnson City,
Tennessee, to reclaim strip mine spoils (19), an abandoned
alkaline ash pond (20), and an eroded acid copper basin soil
material (21). Revegetation with grasses was possible in all
these trials.
15
-------
In summary, land cultivation of shredded municipal refuse
has received little attention, probably due to the lack of data
on economics and associated agricultural production. There has
been a similar lack of data on land application of other
municipal solid wastes, such as lime and alum sludges.
Incorporation of refuse compost into barren lands makes
revegetation possible, particularly with the use of chemical
fertilizers. Refuse incorporation, resulting in soil stabili-
zation and organic matter enrichment, permits the establishment
of a cover vegetation where fertilization alone fails. On
productive agricultural land, equivalent yield increases can_be
obtained more economically with inorganic fertilizers than with
solid wastes or refuse compost. Thus, municipal refuse or
compost application appears more attractive and feasible for
marginal lands than for productive agricultural lands.
LAND CULTIVATION OF INDUSTRIAL WASTEWATERS AND SLUDGES
Industrial hazardous wastes are generally disposed of in
secured chemical landfills or deep wells, or are incinerated.
Some hazardous wastes are recycled, stockpiled, stored, or
disposed into the ocean, if permitted. Formal, routine applica-
tion of industrial hazardous wastes onto land and incorporation
into the surface soil are not widely practiced, except for oil
refinery wastes, and little published data is available.
A number of national conferences are held annually to
discuss the various aspects of treatment and land disposal of
industrial wastes. Recent ones are listed in Table 4.
Land Treatment of Industrial Wastewaters
Land application of nonhazardous organic wastes from food
processing, pulp and paper, textile, tannery, and pharmaceutical
industries has been practiced on a limited scale at several
locations (22). Land disposal of nonhazardous industrial waste-
waters has been well documented (7, 22, 23, 24). Land applica-
tion at most locations is used primarily as a biological treat-
ment of wastewater and disposal method with little or no regard
to agricultural production. Three application methods are
generally used: slow infiltration, overland flow, and rapid
infiltration (23, 25). These methods depend, in various
degrees, on three components: soil organic matter, cover crop,
and microorganisms. Each method is maintained and operated so
that these components can be used in association with the
method's hydraulic conditions, as described below.
Overland flow, or surface flooding, is suitable for fine-
textured soils and generally has a low hydraulic loading. Slow
infiltration, or crop irrigation, is used on soils that have
extensive reaction surfaces and sufficient structure to remove
16
-------
TABLE 4. A LIST OF SELECTED RECENT CONFERENCES PERTINENT TO
LAND CULTIVATION OF INDUSTRIAL WASTES
Conferences
Place
Date
Annual Cornell University Conference
Annual Purdue Industrial Waste
Conference
Soils for Management of Organic
Wastes and Wastewaters
Residual Management by Land Disposal
Disposal of Residues on Land
Land Application of Waste Materials
Treatment and Disposal of Industrial
Wastewaters and Residues
Management of Gas and Leachate in
Landfills
Disposal of Industrial Wastes and
Oily Sludges by Land Cultivation
Acceptable Sludge Disposal Techniques Orlando, FL
Ithaca, NY
West Lafayette, IN
Muscle Shoals, AL
Tucson, AZ
St. Louis, MO
Des Moines, IA
Houston, TX
St. Louis, MO
Houston, TX
Land Disposal of Hazardous Waste
San Antonio, TX
Annually
Annually
March 11-13, 1975
February 2-4, 1976
September 13-15, 1976
March 15-18, 1976
April 26-28, 1977
March 14-16, 1977
January 18-19, 1978
January 31-February 2,
1978
March 6-8, 1978
-------
BOD, nitrogen, and phosphorus. Rapid infiltration, known as
aquifer recharge, is used to remove considerable amounts of
water through limited soil surface area. This method is suit-
able to coarse-textured soils, because its BOD and nutrient
removal capacities are lower than those of the overland flow and
slow infiltration methods. A good cover crop, preferably forage
species, is essential in the slow infiltration and overland flow
methods; it is not nearly as important in the rapid infiltration
method.
Land Cultivation of Industrial Sludges
Among the industrial sludges, oily wastes have been widely
disposed of by land cultivation, also called land farming by
the oil industry (26, 27, 28). Ongoing experiments by several
major oil companies are concerned with waste degradation rates,
heavy metal movement in soil, runoff, as well as the potential
for groundwater contamination, and uptake of trace elements and
salts by vegetation grown on the oil-treated soil.
Probably the most extensive study of oily waste application
to soil was that reported by Kincannon at a Texas oil refinery
(27). In the 18-mo field study, three waste oil types - crude
oil tank bottoms, a fuel oil (Bunker C), and a waxy raffinate -
were applied to a sandy clay loam at approximately 10 percent
oil (soil basis). Mixing of the viscous oily matter into the
soil was not successful until the air temperature reached about
27°C (80°F). Reported rates of degradation were on the order of
27,600 1/ha (70 bbl/ac) per month for the oily matter. Bacteria
assimilation was assumed to be responsible for the oil degrada-
tion, but the increased number of microbial populations observed
was not shown to be hydrocarbon-utilizing bacteria.
Another study of oily waste application was conducted at a
New Jersey refinery. The types of oily sludges cultivated at
this refinery include crude oil cleanings, slop emulsion,
distillate, additives tanks, and API separator bottoms, as well
as other cleaning residues (28). The average composition of
cultivated sludges is approximately 25 percent oil, 40 percent
solids, and 35 percent water. The application rate is approxi-
mately 1,000 t/ha (450 tons/ac) per year. Sludges are spread
to a final depth of about 6.7 cm (3 in) by a track dozer and
are harrowed into the soil.
In another study, Dotson et al. (26) discussed land culti-
vation operations for oily waste disposal at three refineries:
two in Texas, and one in Illinois. Based on the results, they
concluded that:
t Soil microorganisms can oxidize and decompose a large
quantity of petroleum hydrocarbons under a wide range of
soil and environmental conditions.
18
-------
Land cultivation of oily wastes improves soil physical
and chemical properties.
Decomposition of the wastes may be accelerated by
judicious use of lime and fertilizer, artificial
drainage, and tillage.
t Land cultivation is an economical and comparatively
foolproof method to dispose of oily wastes.
Many private firms now practice land cultivation of
industrial sludges on a trial basis. However, very little data
has been published on these activities. In California, 4 of the
11 Class I disposal sites that receive industrial hazardous
wastes practice land cultivation, but only on a small scale.
Land cultivation is not recommended by California regulatory
agencies for disposal of wastes containing significant amounts
of heavy metals and organic substances that are highly toxic
in dust form (29).
Table 5 summarizes some representative research projects
on industrial sludge application to agricultural lands. Except
for the research at Michigan and Texas, other projects have been
completed.
Available data indicate that industrial sludges most well
suited for land cultivation have been either organic (e.g., oil
refinery, paper and pulp, cannery, nylon, and fermentation
residues) or treated inorganic wastes (e.g., steel mill sludge)
containing insignificant levels of extractable heavy metals.
When the waste material is applied to an agricultural land, it
is generally used as a soil amendment and/or low-analysis
nitrogen fertilizer. The suitability of an industrial waste
for land cultivation will depend on many characteristics,
including: concentrations of chemical elements in the soluble
and insoluble forms, concentrations of soluble salts and hazard-
ous organic compounds, bulk densities of waste solids, pH, BOD,
and flammability and volatility.
Soil, if properly managed (i.e., pH adjustment, waste
loading, cultivation, runoff control, among others), can often
serve as an effective disposal sink for industrial organic
wastewater and sludge. However, if a specific soil cannot
assimilate the applied quantity of these wastes, the soil will
become anaerobic, resulting in nuisances and potential water
pollution and, possibly, failure of the system. Moreover, unless
the waste materials are detoxified or decomposed to nondeleter-
ious products by the soil or weather, repeated waste application
will eventually load the upper soil zone to its ultimate
capacity. As a result, waste disposal by land cultivation at
the site would have to be terminated. A possible solution to
19
-------
TABLE 5. SELECTED RESEARCH PROJECTS ON APPLICATION
OF INDUSTRIAL SLUDGES TO AGRICULTURAL LANDS
o
Invest!gator(s)/location
Jacobs/Alpena, Michigan
Jacobs/Manistee County,
Michigan
Jacobs/Kalamazoo County,
Michigan
Cotnoir/Seaford, Delaware
De Roo/Conn. Agr. Expt. Sta.
Nelson/W. Lafayette, Indiana
Pol son/HaIsey, Oregon
Noodharmcho and Flocker/
Davis, California
Brown/College Station, Texas
Waste type
Hardboard
Paperboard
Paper mill
Nylon
Mycelium
(fermentation)
Steel mill
Refractory metals
processing
Cannery (tomato)
Refinery (API pit)
Crops grown
Wheat
Corn
Corn, beans
Corn
Tomatoes, oats,
tobacco, corn
Corn, soybeans, wheat
Ryegrass
Wheat, barley
Burmuda grass
-------
the problem would be to strip the surface 60 cm (12 in) of soil
and replace it with topsoil that has previously received no
waste, a very costly endeavor.
21
-------
SECTION 4
WASTE CHARACTERISTICS AND QUANTITIES
RELATED TO LAND CULTIVATION
Tables 6 through 8 present available Information on the
waste types, characteristics, quantities, and special disposal
considerations for industrial wastewaters/sludges suitable for
land cultivation. The information presented is a synthesis of
data obtained from published and unpublished data and from.
industry representatives, trade associations, and individuals
currently involved in related research (30-42).
Industrial wastes are normally considered suitable for land
cultivation if they comply with the following criteria:
The organic portion biologically decomposes at a
reasonable rate.
Does not contain material at concentrations toxic to
soil microorganisms, plants, or animals. In addition,
there must be reasonable assurance that long-term toxic
effects resulting from accumulation through absorption
or ion exchange can either be prevented or mitigated.
Does not contain substances in sufficient concentration
to adversely affect the quality of the groundwater.
Does not contain substances in sufficient concentration
to adversely affect soil structure, especially the
infiltration, percolation, and aeration characteristics.
Industrial wastes most suitable for land cultivation are
generated primarily by industries that process organic materials
Some of these industries involve the following:
Food processing (as in canneries and dairies)
Textile finishing
Wood preserving
Pump and paper production
Organic chemicals production
Petroleum refining
Leather tanning and finishing.
22
-------
TABLE 6. INDUSTRIAL WASTEWATER/SLUDGE CHARACTERISTICS
SIC * Industry
20 Food « kindred products
203 Fruits a vegetables
?02 Dairy products
2011 Meatpacking
2061 Cane sugar
20.12 Halt beverages
2016 Poultry dressing plants
All of the above
223, Textile finishing
225,
226
PO 2491 Hood preserving
CO
26 Paper 5 allied
products (pulp
ft paper, paper-
board 1 fiber-
board Hills)
2024 Organic fibers.
nnn-cellulo-jic
2U3 Pharmaceuticals
284 Soap & other
detergent
Haste Type
Raw wastewater
Raw wastewater
Raw wastewater
Raw wastewater
Raw waslewater
Raw wastewater
Secondary wastewater treat-
ment sludges ft screenings
Secondary wastewater treat-
ment sludge
Raw wastewater
Primary* ' wastewater
treatment plant sludge
S cellulostc fiber
fines
Secondary wastewater
treatment
Haste mycel lun
Raw wastewater
Characteristics "'
BOO COD SS JJ)S OSG pH TKN-H _P C.I.
200-4,000 300-10,000 200-3,000 500-2,000 4-12 HMOO
1,000-4,000 400-2,000 4-11 1-13 10-200 46-1,931)
nOO-2,100 400-1,300 300-1,200 70-170 7-5(1 350-2,100
100-2,000 500-4,000 300-3,000 700-4,000 1-15 0-13
300-1, HOD 500-1,000 5-7
1,100 560 43
Sec Note n
See Mote 12
BOD COD SS TS OH Phenols TKW-H Nlfa-N p OrgN-N
2,800-5,000 11.500-19,600 1,<00 6,340 4-5.5 20-300 39 32 *5 57
Elemental Composition >10J 1-101 0.1-1* 0.01-01% 0.001-0.01*
(« of ash) SI AI, Fe, Kg. Hu Pb.Ba.Sr Zn.Su.Cu.Cr.Nt.B
Na, K,
Tl
Ash Content1^ 25X (oven-dried basis)
Dewatered sludge - 18-221 solids
filler fractionatton -"50Z less than 150 oesh
See Note 12
Moisture pll Sulfur Ca N Zn P Na k Fe Bulk densitjrjdryjrt) _PorosJly_
65% 8 7.11 8.2% 1.91 O.IW 0.111 0.341 0.061 0.21% 0.45 g/cc 78 (vol J)
BOP COD OSG Boron _P _pjl_ SS
100-3,000 120-7,000 0-3,400 <1 25-1,000 2-7 25-800
-------
TABLE 6 (continued)
SIC Industry Haste Type
2116 Organic chemicals Secondary wastewater
treatment sludge
291 Petroleum refining Non-leaded product
tank bottoms
Haste b1o sludge
API separator sludge
Dissolved air flota-
tion float
Slop oil emulsion
solids
Crude tank sludge
291 Petroleum refining Non-leaded product
(con't) tank bottom
Mater bio sludge
API separator sludge
Dissovled air flota-
tion float
Slop oil emulsion
solids
Crude tank sludge
291 Petroleum refining Non-leaded product
(con't) tank bottoms
Waste bio sludge
API separator sludge
Dissolved air flota-
tion float
Slop oil emulsion
sol ids
Crude tank sludge
Characteristics'"
Berry! 1 turn
0.025-0.49
0.0013-0.0014
0.0012-0.43
0.0012-0.25
0.002-0.5
0.0013-0.0032
Cadmium
0.25-0.4
0.16-0.54
0.024-2
0.0025-0.5
0.025-0.19
0.025-0.42
Oil (»t I)
45-83
0.01-0.53
3.0-51.3
2.4-16.9
23-62
21-83.6
Vanadium
9.1-34.6
0.012-5.0
0.5-18.5
0.05-0.1
0.12-75
0.5-62
Lead
12.1-37.3
1.2-17
0.25-83
2.3-1,320
0.25-380
10.9-258
See Note 12
Phenols Cyanide
1.7-1.8 0.005-14.7
1.7-10.2 0.001-19.5
3.8-157 0.00006-43.8
3.0-210 0.01-1.1
5.7-68 ND-4.6
6.1-37.8 0.01-0.04
Chromium Cobal t
12.7-13.11 5.9-0.2
0.05-475 0.05-1.4
0.1-6,790 0.1-26
2.8-260 0.13-85.2
0.1-1,325 0.1-82.5
1.9-75 3.8-37
Molybdenum
0.25-18.2
0.25-2.5
0.25-60
0.025-2. S
0.25-30
0.025-95
Selenium Arsenic Mercury
1.5-22.4 0.005-0.08 0.41-0.44
0.01-5.4 1.0-6.0 0.004-1.28
0.005-7.6 0.1-32 0.04-7.2
0.1-4.2 0.1-10.5 0.07-0.39
0.1-6.7 2.5-23.5 0.005-12.2
5.8-53 - 0.07-1.53
Nickel Copper Zinc Silver
12.4-41 6.2-164 29.7-541 0.49-0.7
0.013-11.3 1.5-11.5 3.3-225 0.1-0.5
0.25-150 2.5-550 25-6,595 0.05-3
0.025-15 0.05-21 10-1,825 0.001-2.0
2.5-288 8.5-112 60-656 0.013-20
12.8-125 18.5-194 22.8-425 0.03-1.3
-------
TABLE 6 (continued)
SIC Industry
Waste Type
Characteristics
(1)
3111 Leather tannlnq S Raw uastewiter'4'
finishing (vegetable)
Secondary wastewater
treatment sludge
COD
COO
<1SG
SS
Cr
Sulflde 11)3 JKN-N pNnol_s.
700-1,800 ?.000-6,000 2-1,200 730-3,310 l.?-50 12-192 300-12,200 210-1,500 6-21
Solids
2-8?.
Cr.Cu.Pb.Zn
Mr,
Ca
Sulfides Phenols
100-1,500 100-500
10-50 1,000-4,000 20-200
ro
en
(1) Units are ppn on a "wet weight" basis, unless otherwise Indicated, except pit.
(2) Adequate data Is not available (in some cases, proprietary data exists, but is not available) to quantify specific components in these waste materials.
(3) Secondary treatment of pulp and paper mill wastewater is not yet common practice. Secondary wastewater treatment sludges are'
expected to be suitable for land cultivation disposal, but qualitative data on specific constituents is not available. The volume
of raw wastewater generated by most pulp and paper mills is sufficiently large to make land requirements excessive for the use
of land cultivation as a disposal method,
(4) As indicated by the range in constituent concentrations, the acceptability for land cultivation depends on the specific source
of this waste material.
-------
TABLE 7. WASTE-SPECIFIC LAND CULTIVATION DISPOSAL CONSIDERATIONS
Industry
Waste Type
2231
ro
Food and kindred
products
Textile
finishing
Specific Potential Hazards Recommended Precautions
2491 Wood preserving
26 Paper and
allied products
2824 Organic fibers,
noncellulosic
283 Pharmaceuticals
2841 Soap and other
detergents
286 Organic
chemicals
291 Petroleum
refining
Wastewater, sludge,
and screenings
Secondary waste-
water treatment
sludge
Wastewater
Primary waste-
water treatment
sludge
Secondary waste-
water treatment
sludge
Waste mycelium
Wastewater
Wastewater treat-
ment sludges
Nonleaded tank
bottoms
High sodium and TDS content
and resulting detrimental
effects on soil properties
and plant growth
Heavy metal content
Pentachlorophenol creosote
and possible contamination
of waste supplies
Contamination with toxic
materials may occur at
some plants reprocessing
secondary materials
High zinc and nitrate
content
High zinc and TDS content
Possible water supply
degradation from excess
nutrients
Potential hazards are
dependent on the specific
chemicals produced
High nickel, copper, vana-
dium, and lead content
Gypsum addition; segrega-
tion of high sodium and
TDS waste streams
Plant and water monitor-
ing; appropriate loading
rate
Appropriate loading rate
about 28 to 37 nr/ha
(3,000 to 4,000 gal/ac)
Sludge analysis and
subsequent appropriate
site design and operating
precautions
Appropriate application
rate and cover crop
Appropriate application
rate and cover crop
Use cover crop with good
nutrient uptake charac-
teristics
Chemical analysis of
sludge to detect poten-
tially hazardous consti-
tuents
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
-------
TABLE 7 (continued)
Industry
Petroleum
refining
Waste Type
Specific Potential Hazards Recommended Precautions
3111
Leather tanning
and finishing
Waste biosludge
API separator
sludge
Dissolved air
flotation float
Slop oil emulsion
solids
Crude tank sludge
Vegetable tannery
wastewater
High chromium and zinc
content
High chromium, zinc,
nickel, and copper content
High chromium and zinc
content
High chromium and zinc
content
High chromium, zinc, and
copper content
High chloride and TDS and
associated detrimental
effects on plant growth
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
Monitoring of soil and
groundwater concentrations
to determine when disposal
site life is expended
Dilution, addition of
gypsum
-------
TABLE 8 . ESTIMATED QUANTITIES OF INDUSTRIAL WASTEWATERS AND
SLUDGES SUITABLE FOR LAND CULTIVATION
INJ
00
Waste quantities*
SIC
20
2011
2016
202
203
2061,
2062
2082
22
2231,
226
24
2491
Industry
Food and kindred
products
Meatpacking
Poultry dressing
plants
Dairy products
Fruits and
vegetables
Cane sugar
Malt beverages
Textile mill
products
Textile finishing
Lumber and wood
products
Wood preserving
Waste type 1975 1980
Wastewater1" 150 170-190
Wastewater1" 87 98-110
Wastewaterf 45 51- 57
Wastewater* 280 320-350
Wastewaterf 68 79- 87
Wastewater1" 87 98-110
Secondary waste- 3.9 x 10 8.5 x 104
water treatment
sludge#
Wastewater1" 1.9 2.2-2.3
1985
190-230
110-140
58- 70
360-440
89-110
110-140
1.8 x 105
2.5-2.9
-------
TABLE 8 (continued)
ro
vo
SIC
26
28
2824
283
2841
286
29
291
Industry
Paper and allied
products
Chemicals and
allied products
Organic fibers,
noncellulosic
Pharmaceuticals
Soap and other
detergents
Organic chemicals
Petroleum refining
and related
industries
Petroleum refining
Waste type
Primary wastewater
treatment sludge^
Secondary wastewater
treatment sludge#
Waste mycelium^
Wastewater"^
Wastewater treatment
sludges*
Non-leaded product
tank bottoms*
Waste bio sludge^
1975
1.4 x
1.7 x
106-
106
4,800
6.3 x
12-1
5.5 x
4.1 x
4.0 x
104
4
106
104
104
Waste quantities
1980
1.6 x 106-
1.9 x 106
7,300
8.1 x 104
17-18
6.8 x 106
5.1 x 104
5.0 x 104
1985
1.8 x 106-
2.1 x 106
9,800
1.0 x 105
20-22
8.5 x 106
6.2 x 104
6.2 x 104
-------
TABLE 8 (continued)
co
o
Waste quantities
SIC
291
Industry Waste type
Petroleum refininq API separator
1975
3.4 x 104
1980
4.2 x 104
1985
5.2 x
104
31
3111
(continued)
Leather and
leather products
Leather tanning
and finishing
(vegetable)
*£/
sludge*
Dissolved air
flotation
float*
Slop oil emulsion
solids*
Crude tank sludge*
Wastewater1"
Secondary waste-
water treatment
sludge*
2.9 x 10
1.7 x 10^
390
3.7 x 10
2.1 x 10
490
4
Total wastewater1"
Total sludge*
2.5
820
735
7,2-7.5 x 10fc
2.3
740
840-920
8.8-9.1 x 106
4.5 x 10
2.6 x 10
610
2.2
680
940-1,160
10.8-11.1 x 10C
*Waste quantities for 1975 based on ref. 1-15 and contacts with industry representatives and current
researchers. Values for 1980 and 1985 assume the 1975 relationship between production and waste
generation, and are based on industry-specific production projections (if available).
fWastewater quantities are given in units of millions of cubic meters per year.
M
Sludge quantities are given in units of metric tons per year on a dry weight basis.
-------
WASTE CHARACTERISTICS
Information on the characteristics of wastes disposed by
land cultivation is often very limited or unavailable. The
scope of this project did not include a sampling program to
improve the available information. Thus, a general description
of wastes suitable for land cultivation follows. Available
specific waste characteristics information is summarized in
Table 6.
Food Processing
Food processing facilities that directly discharge their
wastewater normally utilize secondary wastewater treatment. In
addition, most such facilities screen their wastewater to remove
large suspended materials. Thus, food-related industrial waste-
waters normally consist primarily of organic material that is
readily biodegradable in the soil environment if appropriate
application rates and operating procedures are utilized. Appli-
cation rates are typically limited by the hydraulic loading rate
that is compatible with site-specific soil conditions. High
sodium concentration in wastes from caustic peeling may limit
the application rate or may prevent land cultivation of certain
wastewaters due to sodium induced deterioration of the soil
structure.
Textile Finishing
The textile finishing industry utilizes thousands of organic
chemicals in various production processes. The chemicals fall
into a number of general classifications, including fiber
reactive dyes, dispersed dyes and pigments, flame retardant and
water repellent finishes, and pigments. Wastewaters containing
these chemicals usually receive secondary biological treatment.
Generated sludges are composed principally of waste cellular
material and organic compounds which were passed through the
treatment system. Detailed information is not available on the
suitability of these sludges for disposal by land cultivation,
but preliminary information indicates that land cultivation may
be an appropriate disposal practice. At least three sites are
currently under construction for disposal of textile-finishing
wastewater treatment sludges by land cultivation (39, 41).
Wood Preserving
The wood preserving industry utilizes a variety of chemicals
to inhibit the deterioration of wood products. Several of the
chemicals, such as chromated copper arsenate and flour chrome
arsenate phenol (FCAP), are highly toxic. Consequently, dis-
charge of wastewaters containing these materials is being phased
out in favor of recycling systems for using the wastes (31, 38)
(Harrison, personal communication).
31
-------
Most preserved wood products are treated with pentachloro-
phenol and/or petroleum- and coal tar-based materials. Despite
the potential toxicity of these compounds, wastewaters from
wood preserving plants have been shown to be suitable for land
cultivation. At loading rates of 28 to 37 m3/ha (3,000 to 4,000
gal/ac) per day, bacteria in the soil environment effectively
decomposed these preservative compounds (33).
Approximately 10 to 15 percent of all wood preserving
plants are direct dischargers of secondary treated wastewater.
Recent investigations indicate that sludges resulting from this
wastewater treatment may also be suitable for land application.
Reports detailing the relevant investigations are considered
proprietary and were not available for review.
Pulp and Paper Production
Investigations conducted to date indicate that most seg-
ments of the pulp and paper industry generate wastewater
treatment sludges suitable for land cultivation (30, 38, 40)
(Ruppersberger, personal communication). These segments
manufacture products such as:
Sulphite
Kraft (sulphate)
Semi-chemi cal
Strawboard
Groundwood
Cardboard
Boxed board and paper board.
To analyze the acceptability of pulp and paper industry
sludges for land cultivation disposal, it is helpful to divide
them into three cateogries:
§ Primary sludges composed of about 50 percent or more
calcium carbonate solids (or lime sludges)
Primary sludges composed principally of cellulosic
fibers
Biological sludges resulting from biological wastewater
treatment.
Lime Sludges--
In areas where
are land cultivated
stone. The appropriate
on:
soil acidity is a problem, lime sludges that
can serve as a substitute for ground lime-
sludge application rate normally depends
Calcium carbonate content of the sludge
Soil pH and texture
32
-------
Type of crop grown
Rate of nitrogen application
Particle size of the sludge solids.
Primary Sludges Composed of Cellulosic Fibers--
Primary wastewater treatment sludges (composed principally
of cellulosic fibers) do not possess the utilization capabilities
of lime sludges. However, the sludges do contain from 3 to 6 kg
nitrogen per metric ton (12 Ib/ton) of solids on a wet weight
basis (in addition to other nutrients). The release of available
nitrogen depends upon particle surface area, aeration, tempera-
ture, moisture, and the availability of other nutrients.
Biological Sludges Resulting from Biological Wastewater
Treatment--
Sludges resulting from biological wastewater treatment are
also normally acceptable for disposal by land cultivation.
However, application rates may be limited by the nitrogen
requirement of the crop. If these sludges are applied to fine
textured soils, particular attention must be paid to maintaining
aerobic conditions during the decomposition process.
Organic Chemicals Production
Various categories of organic chemical products include:
Synthetic noncellulosic organic fibers
Pharmaceuticals
t Soap and other detergents
t Miscellaneous organic chemicals.
Synthetic Noncel1ulosic Organic Fibers--
Manufacturing facilities producing synthetic noncel1ulosic
organic fibers (such as nylon or polyester) and that are direct
dischargers of their wastewater typically employ secondary
wastewater treatment prior to discharge. The sludges are
composed principally of waste cellular material and are usually
not contaminated by constituents that would be detrimental to
soil productivity. After land cultivation, the sludges decom-
pose to provide a low-grade source of plant nutrients, particu-
larly nitrogen. Characteristics of these sludges are similar
to those of domestic wastewater treatment sludges (37).
Pharmaceuticals--
Microbial pharmaceutical production of various organic
acids (such as citric acids) and antibiotics (such as tetracy-
cline and terramycin) generates a fermentation residue, which
consists primarily of spent fungal mycelial tissue and lime.
The lime is added to the residue to raise the pH to the neutral-
to-slightly-alkaline range.
33
-------
Zinc is often added to the residue to control microbial
growth during the fermentation process, in which case it is
present in the waste mycelium. The concentration of zinc in
the residue ranges from approximately 10 to 10,000 ppm, depending
on the exact control procedures utilized. Some mycelial residues
may not be suitable for land cultivation because of high zinc
concentrations. In addition, land cultivation of this waste
may be limited by its soluble salt concentration, which inter-
feres with water adsorption and nutrient uptake by the plants.
Soap and Other Detergents--
Wastewaters generated in the manufacture of soap and other
detergents are contaminated with organic materials and inorganic
nutrients, particularly phosphorus. Land cultivation of these
wastewaters provides for decomposition of the organic wastes and
utilization of the inorganic nutrients if a cover crop is grown.
Particular attention must be paid to nitrate and soluble salt
accumulation in the soil since high nitrate levels may result
in groundwater contamination. Salt accumulation may deteriorate
soil structure, reducing permeability (32).
Miscellaneous Organic Chemicals--
Biological treatment of wastewater from the production of
miscellaneous organic chemicals generates sludges that may be
suitable for land cultivation. These sludges are composed
primarily of waste cellular material that is readily biodegrad-
able under aerobic conditions. However, these sludges may be
contaminated with toxic organic chemicals and/or heavy metals,
depending on the product mix at the particular manufacturing
facility.
The product mix varies widely from plant to plant, and even
varies from day to day within many plants. Thus, the suita-
bility of the resulting sludge for disposal by land cultivation
may vary, and must be assessed on an individual basis. If land
cultivation is used for sludge disposal, the accumulation of
nondegradable constituents (e.g., heavy metals) in the soil must
be monitored to determine when the site life has been expended.
The useful life of the disposal site can be extended by pre-
treatment of individual process wastewater streams, which
contribute the contaminants of concern to the overall wastewater
flow from the plant. An alternative approach is to adjust waste
application rates to control total toxic contaminant input to
any portion of the site.
Petroleum Refining
Six sludges suitable for land cultivation without pretreat-
ment are generated by the petroleum refining industry:
Nonleaded tank bottoms
t API separator sludge
34
-------
t Dissolved air flotation float
Soil oil emulsions solids
t Crude tank sludge
Waste biosludge.
These sludges vary from 3 to 83 percent oil by weight and
contain up to 7,000 ppm of various heavy metals (e.g., zinc,
copper, nickel, chromium). The oil and heavy metal concentra-
tion depends on the particular waste type, the source of crude
oil being processed, and the types of refining processes
utilized. Currently, land cultivation of these sludges serves
principally as a disposal methodology for the inorganic fraction
and as a treatment method for the organic fraction. Microbial
action decomposes the organic fraction of the sludge when
aerobic conditions are maintained. Inorganic components of the
waste will not degrade and consequently accumulate in surface
and subsurface soil horizons. Many of these waste sludges
.contain substantial quantities of heavy metals; thus, use of
oily waste land cultivation sites for crop production needs to
be carefully investigated. Information currently available
indicates that these sites are not suitable for production of
crops for direct human consumption.
Leather Tanning and Finishing
It has not yet been determined whether wastewater/sludge
generated by chrome leather tanning and finishing 'plants is
suitable for land cultivation (34). The suitability of vegetable
leather tanning and finishing wastes for land cultivation varies
from plant to plant, and depends on factors such as total
dissolved solids (TDS) concentration. A high TDS concentration
in the wastewater results from salt used to preserve the hides
before tanning. The level of TDS concentration depends on the
housekeeping practices in each plant and on the particular
method of hide preservation. Wastewaters with TDS concentra-
tions in excess of 3,000 mg/1 are not suitable for application
to most soils since the high sodium content is detrimental to
the soil, causing a structural breakdown and decreased perme-
ability.
Sludge from secondary wastewater treatment at vegetable
leather tanning plants is normally suitable for land cultivation.
This sludge is composed mainly of waste cellular material pro-
duced in the treatment process and is typically not contaminated
by constituents that would be detrimental to soil productivity
(43). The TDS concentration of the sludge is affected by the
same variables as is the wastewater, e.g., plant housekeeping
practices and the method of hide preservation. In addition,
the percent solids concentration of the cultivated sludge is a
factor, since increasing the solids concentration has the effect
of decreasing the TDS concentration. Sludge application rates
must be decreased for the higher TDS concentrations. Further, a
35
-------
high IDS concentration in a sludge may make it unsuitable for
land cultivation. In general, a sludge with a high solids
content will be acceptable for land cultivation at a reasonable
application rate with little risk of soil damage due to sodium.
Other Industries
Information from all industrial sources on the suitability
of wastes for land cultivation is not currently available. Data
are particularly lacking for industries that generate principally
inorganic wastes. However, some inorganic wastes (e.g., gypsum)
could likely be disposed by land cultivation. Since the wastes
are inorganic, they would not be significantly affected by
microbial decomposition and would accumulate in the soil environ-
ment. Thus, land cultivation of inorganic wastes would serve as
a disposal option and normally would not be associated with crop
production. A potential exception is lime sludges generated as
a result of water treatment. In areas where soil acidity is a
problem, lime sludges might be used to neutralize soil acidity
in fields used for crop production. Lime sludges might also be
cultivated in conjunction with wastes to maintain soil pH at,
or above, 6.5 to immobilize most heavy metals. N
WASTE-SPECIFIC DISPOSAL CONSIDERATIONS
Generalized considerations for disposal of industrial
wastewaters/sludges by land cultivation are discussed in detail
in Sections 10 and 13. Any wastes to be land cultivated should
first be chemically characterized to identify specific problems
that might arise. After a waste has been adequately charac-
terized, appropriate disposal sites can be identified. In
addition, the appropriate hydraulic and organic loading rates
that are compatible with specific waste and site characteristics
can be determined. Necessary soil, crop, and groundwater moni-
toring programs can also be developed.
Waste-specific land cultivation disposal considerations are
summarized in Table 7. The constituents of concern in a specific
waste depend on the industry and particular manufacturing
facility that generate the waste.
WASTE QUANTITIES
The estimated quantities of industrial wastewaters/sludges
suitable for land cultivation in 1975, 1980, and 1985 are
presented in Table 8. Estimates of the waste quantities gener-
ated in 1975 were obtained from various published and unpublished
reports, and contacts with industry representatives and trade
associations (30, 35, 36) (Tanners' Council of America,, personal
communication; Harrison, personal communication). Projections
of the waste quantities generated in 1980 and 1985 assume the
1975 relationship between production and waste generation and
36
-------
are based on industry-specific production projections (if avail-
able) for the overall increase of solid waste generation.
Although increased attention to in-process modifications to
enhance resource recovery is anticipated, increased pollution
control residuals due to implementation of regulations are also
anticipated.
The detailed
below:
information presented in Table 8 is summarized
Year
1975
735
7.2-7.5
1980
840-920
8.8-9.1
940
10.8
1985
-1 ,160
-11.1
Waste Type
Wastewater
(106 m3/yr)
Sludge (106 metric
tons dry weight basis)
Recent reports estimate the total quantity of generated
sludge on a dry weight basis to be 237 x 10b t/yr (44), which
indicates that only about 3 percent of all industrial sludge is
likely to be suitable for land cultivation. Similarly, the total
quantity of industrial wastewater suitable for land cultivation
is only about 1 percent of the total.
37
-------
SECTION 5
MECHANISMS OF WASTE DEGRADATION
AND VOLUME REDUCTION
If properly managed, soil may serve as an effective disposal
sink for many wastes. In land cultivation, it is preferred
that the chemical constituents in the waste be retained in the
surface layer and/or decomposed by the various soil processes.
In particular, the organic fraction must be biologically
degradable at reasonable rates. Current information on the_
relative persistence of various chemical constituents in soils
is substantial; however, information on the kinetics of the
individual degradation processes is fragmentary and inadequate.
The important processes that contribute to waste volume reduc-
tion include microbial degradation, nonbiological (chemical and
photochemical) degradation, and evaporation and volatilization
(Figure 1).
MICROBIAL DEGRADATION
Biological processes are greatly affected by many wastes
commonly applied to soils. These processes, in turn, decompose,
utilize, or alter the added wastes. The soil microbial popula-
tion constitutes a biochemically complex system capable of
producing unique enzymes that degrade a large number of organic
substances (45, 46).
Organisms Important to Waste Utilization
There are normally large numbers of diverse microorganisms
in soils, consisting of several groups that are predominantly
aerobic in well-drained soils. These microorganisms normally
adhere to the surfaces of the soil colloids. The majority of
groups is heterotrophic, deriving energy from the breakdown
of organic substances. These are the dominant microorganisms
responsible for the decomposition of applied wastes.
The principal groups of microorganisms present in surface
soils are bacteria, actinomycetes, fungi, algae, and protozoa
(48). In addition to these groups, other micro and macrofauna
are often present, such as nematodes and insects.
The bacteria are the most numerous and biochemically active
group of organisms, especially at low oxygen levels. Bacteria
38
-------
VOLATILIZATION**
MOVEMENT*
(HORIZONTAL -
OR VERTICAL)
CO
MICROBIAL
DEGRADATION
WASTE
ADSORBED
PHASE
1
WASTE
SOIL VAPOR
PHASE
K5
K
CHEMICAL
DEGENERATION
Jii.
MICROBIAL
DEGRADATION
K
WASTE
SOIL SOLUTION
PHASE
K
CHEMICAL
DEGRADATION
WASTE PARTICULATE PHASE
LEACHING OR
HORIZONTAL
MOVEMENT
PHOTOCHEMICAL
DEGRADATION
MOVEMENT*
(HORIZONTAL OR VERTICAL)
K - RATE CONSTANT
Kl,K2,... - EQUILIBRIUM CONSTANT
* - OCCURS DURING RAINFALL
** - OCCURS ONLY UNDER UNSATURATED CONDITIONS
Figure 1
Mechanisms of waste degradation.
-------
are primarily responsible for transformations of nitrogen,
sulfur, and trace elements in soils. Of the diverse species
that exist, many bacteria flourish only under certain environ-
mental conditions or carry out explicit functions, such as the
oxidation of ammonium to nitrite by nitrosomonas and of nitrite
to nitrate by nitrobacter (49).
Actinomycetes are less numerous than bacteria. They
usually predominate in soils of low moisture content and in
organic material in the later stages of decomposition. These
microorganisms can decompose a variety of comparatively resistant
substances.
Fungi often grow vigorously after initiating decomposition.
They have extensive mycelial branching and compete effectively
with bacteria for simple carbohydrates and bioproducts. Many
fungi can readily attack cellulose, and a few species can utilize
lignin, which is very resistent to decomposition. Fungi have
much lower nitrogen demands and are more tolerant to acidity
than bacteria (46).
Soil animals make up a large group of microorganisms. The
more prominent ones with respect to waste utilization are the
protozoa, nematodes, and earthworms. All soil animals may
assist during waste decomposition. Earthworms are important
in mixing organic wastes with the soil, which improves soil
structure, aeration, and fertility (45). However, nematodes
may impede waste degradation, feeding on bacteria, fungi,
algae, protozoa, and other nematodes (46). Their ecological
importance, therefore, is concerned with their effect on total
microbial activity through destruction of the species they
consume.
Soil Environment and Activity of Microorganisms
In general, conditions favorable for plant growth are also
favorable for the activity of soil microorganisms. Environ-
mental factors influencing plant growth have been well documented
and include soil pH, air temperature, soil water content, and
nutrients (45, 46, 50, 51, 52).
Soil pH--
The optimum pH for bacterial growth is near 7. Only a few
species live when the pH is above 10 or below 4 (46). Acti-
nomycetes thrive in neutral or alkaline soils with a lower pH
limit of about 5. Nearly all fungi grow best at pH 7 or above,
but they are far more tolerant to acidity than are other micro-
flora; some fungi grow rapidly at pH 2 or lower. Soil animals
are adversely affected by acidity, especially when the pH is
below 5.
40
-------
Air Temperature--
Many species can tolerate a fairly wide temperature range,
but the optimum temperature is usually within a few degrees of
the upper part of the range (53). As a general guideline, the
activity of a species will double for each 10°C rise in tempera-
ture until the optimum level for the particular microorganism
is reached.
Soil Water Content--
The decomposition process is typically not restricted by
moisture if the soil water content is kept above a certain
minimum (usually between 30 and 90 percent of the water holding
capacity of soil). However, poor drainage or excess water
reduces the available oxygen levels and can retard microbial
decomposition of applied organic wastes (54). Actinomycete
populations usually increase, while bacteria and fungi popula-
tions decrease at lower soil moisture levels. Soil organisms
become essentially inactive when the soil water content drops
below the level where plants wilt.
Nutrients--
Soil organisms require basically all nutrient elements
required for the growth of higher plants (45). Consequently,
in fertile soils, inorganic nutrients seldom need to be added
for the nutrition of organisms decomposing plant and animal
tissues. However, when a highly carbonaceous waste (with a C/N
ratio >35) is added to the soil, inorganic nitrogen is rapidly
used by the organisms for metabolic processes, especially for
the production of cell protein (45, 46). Additional nitrogen
must therefore be supplied to attain an optimal waste decompo-
sition rate.
Deficiencies of phosphorus and sulfur also markedly affect
microbial growth. These nutrients are usually present in
adequate quantities in most organic wastes to satisfy the needs
of the majority of soil microorganisms. However, if the waste
is a comparatively pure organic compound such as cellulose, the
available supply of several nutrient elements may be reduced to
the extent that microbial growth is adversely affected (46).
Aerobic vs. Anaerobic Decomposition
The following generalized equations depict the microbial
metabolism of organic compounds in soil under aerobic and
anaerobic conditions (51):
41
-------
Aerobic:
(CHO)nNS
CO? + microbial cells and storage
products (60%*)
+ NH* + H2S + H20 + Energy
4-
NO!
S0
2-
Anaerobic:
(CHO)nNS
+ organic
H2S
+ H
>- C02 + microbial
products (20%*)
intermediates + CH/
(70%) (5%;
,0 + Energy
cells and storage
+ H + NH
The main products of aerobic metabolism are C02, 1^0, and
microbial cells. In anaerobic metabolism, where decomposition
is not complete, there is an accumulation of intermediate sub-
stances such as organic acids, alcohols, amines, and mercaptans.
Because the energy yield during anaerobic fermentation is small,
fewer microbial cells accumulate per unit of organic carbon
degraded. Also, while NOJj and S042~ are the end products of
organic nitrogen and sulfur compounds under aerobic conditions,
and NH| accumulate under anaerobic conditions (55). When
is present and a soil becomes anaerobic, NOo may be denitri-
'4
is present and a soil becomes anaerobic,
fied with the nitrogen lost as a gas.
Many types of organic substances are found in industrial
sludges. Leithe (56) has listed organic components of indus-
trial waste effluents according to their source. The biodegrad-
ability of some commonly known organic substances has been
arbitrarily summarized as follows (51):
Readily decomposable: amino sugars, carbohydrates,
fatty acids, nucleic acids, and proteins
Slowly decomposable: cellulose, detergents, fats,
humic compounds, hydrocarbons, lignin, pesticides,
phenols, plant and bile pigments, tannin, and waxes.
In recent years, considerable emphasis has been placed on
studying the biodegradabi1ity of many organic substances that
are considered potential environmental toxins (57). Some of
*The percentage values are estimates
of the original organic compound(s)
microbial population.
of the carbon distribution
after metabolism by the
42
-------
these substances are phenolic compounds, chlorinated hydrocarbon
pesticides, nitrosamines, detergent residues such as alkyl-
benzene sulfonates (ABS) and nitrilotriacetate (NTA), and
petroleum products.
The simpler phenols (i.e., mono- or disubstituted phenols)
generally undergo hydroxylation. This generally results in the
formation of a catechol-type product which is the precursor to
ring cleavage and dissolution of aromaticity by microorganisms.
Initial biochemical activity may occur with the substituent
groups; however, this initial activity depends on the biochem-
ical activity or position of the substituent group on the
aromatic ring. In addition to these reactions, phenols may
undergo conjugation, methylation and condensation reactions
leading to more complex molecules (57).
More studies have been conducted on the biodegradation of
pesticides in soils than on most other compounds. The principal
biochemical reactions responsible for microbial degradation of
pesticides include alkylation, dealkylation, amide or ester
hydrolysis, dehalogenation, dehydrohalogenation, oxidation,
reduction, dehydroxygenation, ring cleavage, ether cleavage,
condensation, and conjugate formation (58).
The chemical structure, nature, and position of substitut-
ing groups of the pesticides affect the extent and rate of
microbial degradation (50). This is demonstrated by the per-
sistence of various pesticides in soils from normal rates of
application and field conditions (Figure 2). In addition, the
dosage, particle size, distribution in soil, and previous appli-
cations all influence the rate of decomposition of pesticides in
the soil (59). A high application rate may be toxic to some
species which would decompose the same chemical at lower con-
centrations. If the substance is banded or not well mixed with
the soil, the concentration may be too high in the localized
areas for growth of otherwise active organisms. Materials of
relatively large particle size will decompose more slowly than
those of smaller particle size because they will present less
surface area for organisms capable of degrading the compound.
Subsequent additions will therefore decompose more quickly.
/
In summary, although some of the toxic organic substances
do persist in soils, microbial degradation will eventually
proceed if the substances are adsorbed in the soil surface for
a sufficient period of time. There is, however, limited infor-
mation on environmental factors affecting degradation of these
substances as well as the microorganisms and enzymatic reactions
involved.
43
-------
CHLORINATED HYDROCARBON INSECTICIDES
UREA, TRIAZINE AND PICLORAM HERBICIDES
BENZOIC ACID AND AMIDE HERBICIDES
PHENOXY, TOLUIDINE AND NITRILE HERBICIDES
II
CARBAMATE AND ALIPHATIC ACID HERBICIDES
1!
PHOSPHATE INSECTICIDE
I I
0 1
9 ,
12
15
16
MONTHS
Figure 2. Persistence in soils of several classes
of insecticides and herbicides (52).
-------
NONBIOLOGICAL DEGRADATION
Nonbiological degradation processes play an important role
in the dissipation of many organic substances in soils, includ-
ing pesticides. In particular, considerable evidence has been
reported on the importance of chemical hydrolysis and photo-
chemical degradation (61). Other reactions, including oxidation-
reduction, are important for certain compounds.
Chemical Degradation
Chemical degradation of waste materials in soil is a com-
plex phenomenon. Various mechanisms of chemical degradation
or transformation have been found or postulated, including
oxidation, reduction, hydrolysis, isomerization, and polymeri-
zation, the degradation rate depends on whether the reaction
occurs in solution or on an absorbent surface, and is usually a
function of pH; redox potential (Eh); surface acidity; and the
nature, concentration, and availability of catalytic sites (47).
Hydrolysis reactions are important steps in the degradation of
many organic compounds, including chloro-triazine herbicides
and organophosphate insecticides. These reactions are catalyzed
by clay present in the soil (62).
According to Harris (63), there is evidence that atrazine,
simazine, and propazine were converted partially to their
hydroxy derivatives during incubation in soils at 30°C for 8 wk.
The amounts of hydroxy derivatives formed were not affected by
the addition of 200 ppm sodium azide as a microbial inhibitor.
Evidence for the chemical hydrolysis of diazinon was obtained
by comparison of soil systems and soil-free aqueous systems
containing diazinon (62). In soil systems, the rate of degrada-
tion was related to the extent of initial diazinon sorption and
to the organic matter content and pH of the soil. In soil-free
systems, diazinon hydrolysis was acid- or alkali-catalyzed but
was slow compared to soil systems of comparable pH (2 percent
per day at pH 6 compared to 11 percent in a Polygan soil). In
a microbial medium inoculated with an aqueous soil extract,
diazinon was stable for at least 2 wk, suggesting the absence
of microbial degradation during this time period. The degrada-
tion of diazinon in soil was also reportedly enhanced by
increased temperature and soil moisture content (64).
Photochemical Degradation
Chemical reactions induced by electromagnetic radiation
represent a potentially important pathway for alteration and/or
degradation of many organic substances applied to soil. To
undergo photodecomposition, a compound must first absorb light
energy. The initial phase of photochemical degradation
frequently involves homolytic fission of chemical bonds to form
free radicals (65). The free radicals are unstable intermediates
45
-------
and enter into subsequent reaction with the solvent (soil
solution), with other molecules or radicals of the organic
compound, or with other reactants. Thus, the overall results
of the photochemical reaction may be isomerization , substitution
or oxidation. The type of reaction occurring is dependent on
the physical state of the waste, the solvent, and the presence
of other reactants such as oxygen (65). Also important is
whether the waste is in the adsorbed or unadsorbed state.
Photochemical reactions have been reported for a wide
range of pesticide groups, including the chlorinated cyclodiene
insecticides, chlorinated benzoic and phenylacetic acids,
triazines, ureas, and dinitroaniline and picolinic acid
herbicides (61). However, the role of photochemical reactions
in soil pesticide degradation remains uncertain.
During a study conducted by Hatayama and Jenkins (66), a
considerable amount (85 percent) of organic lead was converted
to inorganic lead through air oxidation or photodegradation
during the 30-day test period. A spreading or weathering
method used was recommended by the American Petroleum Institute
to dispose of the leaded gasoline tank wastes. There is evidence
that polybrominated biphenyls (PBB's) and similarly structured
toxic organic compounds also degrade photochemically (67).
Nevertheless, photochemical degradation should generally
play a minor role in land cultivation since the waste is incor-
porated into the soil, thus reducing the amount of light received
by the waste. Likewise, photochemical degradation assumes minor
importance when mobile wastes are leached from the zone of photo-
lytic influence. Storage of wastes in open lagoons will expose
the material, possibly for relatively prolonged periods. Some
photochemical degradation could occur under these conditions.
EVAPORATION AND VOLATILIZATION
In land cultivation of wastewaters and sludges, evaporation
is a major mechanism of volume reduction. The rate of evapora-
tion from a wet soil is controlled by the same environmental
conditions that control the rate of evaporation from bulk water.
Frequent mixing of the waste with soil will increase evaporation
and decrease the probability of developing anaerobic conditions.
Volatilization, though intimately associated with evapora-
tion, is concerned with the dissipation of waste constituents,
rather than water, into the atmosphere. The magnitude of
volatilization loss depends on the soil moisture content,
chemical and physical properties of the waste and soil, atmo-
spheric conditions (temperature, wind velocity, relative
humidity, etc.), and application method (68). In land cultiva-
tion, mixing the waste with soil would significantly reduce
46
-------
volatilization loss due to increased adsorption of the chemical
by soil organic matter and clay, and the decreased vapor pressure
of the waste material.
Soil water content is one of the most important factors
affecting volatilization. Chemicals vaporize faster from wet
(but not saturated) soils than from dry soils, primarily
because water increases the vapor pressure of the chemicals by
competing for the adsorption sites (69). Also, as the water
evaporates from the surface, the water-chemical solution moves
toward the evaporating surface by capillary action, thus
enhancing chemical loss by volatilization. Increasing the
waste concentration, diffusion rate, air flow rate, or air
temperature will result in an increased rate of volatilization.
In land cultivation practices, the volatilization rate of soil-
incorporated waste will likely be controlled by diffusion of the
waste constituents in the liquid or gaseous phase, the mass flow
of water to the soil surface, and the vapor pressure of the
consti tuents.
Volatilization is one of the major pathways of pesticide
loss from field soils. Willis et al. (70) measured atmospheric
concentrations of dieldrin over field plots under three
different regimes. In the plots designated for flooded treat-
ment, 10 cm (3.9 in) of water were applied; for moist treatment,
1/3 to 1 bar tension; for nonflooded treatment, no water other
than natural rainfall. High atmospheric concentrations of
dieldrin were found over all plots immediately after water
application. It was calculated that volatilization losses
during a 5-mo period were approximately 2 percent from the
flooded plots, 18 percent from the moist plots, and 7 percent
from the nonflooded plots. In addition to the effects of soil
moisture on volatilization, it was shown that air temperature
influenced the volatilization rate more than any other climatic
variable measured.
Some of the persistent organic chemicals can be lost from
the soil surface through volatilization. In a laboratory study,
Farmer et al. (71) calculated that uncovered hexachlorobenzene
(HCB) volatilized at 317 kg/ha/yr (283 Ib/ac/yr). The corres-
ponding volatilization losses when the chemical was covered with
1.9 cm (0.75 in) of soil and 1.43 cm (0.56 in) of water were
4.56 and 0.38 kg/ha/yr (4.07 and 0.34 Ib/ac/yr), respectively.
When the soil water content or bulk density (through compaction)
was increased, HCB flux through soil decreased, thereby reducing
volatilization of, the chemical.
47
-------
SECTION 6
EFFECTS OF WASTE APPLICATION ON SOIL PROPERTIES
Chemical, physical, and microbiological properties of soil
are known to be affected, to some degree, by land cultivation of
municipal refuse or industrial wastes. However, little infor-
mation is available on the persistence or duration of these
effects on the surface soil or subsoil.
PHYSICAL PROPERTIES
In a study of land cultivation, Hart et al. (11) applied
both prestabilized composted and fresh refuse to a soil to
evaluate the capability of the land to accept waste. Although
no physical properties of the soil were measured, improved soil
tilth was observed.
Additions of shredded municipal refuse to a Sagehill loamy
sand resulted in improved moisture retention, especially prior
to significant decomposition of the carbonaceous refuse (1). The
bulk density of the waste-amended soil decreased initially due to
the low density of the carbonaceous additive and increased soil
pore space, but bulk density gradually increased as the waste
decomposed. The infiltration rate was not affected by applica-
tions of shredded waste up to 448 t/ha (200 tons/ac).
Improvements in soil physical properties resulting from
waste additions can appreciably reduce surface runoff and erosion.
In a laboratory study, wind erosion was reduced by 88 percent
when a Sagehill loamy fine sand treated with 896 t/ha (400
tons/ac) of shredded municipal waste was subjected to a 48 km/hr
(30 mph) wind at the soil surface for 5 min (3). The waste
products must be well mixed with the surface soil to accomplish
this degree of erosion control.
According to Volk (12), the effect of municipal refuse
applications on physical properties of soil may endure only until
the easily decomposable paper products have disappeared. He
suggests that addition of organic matter to the soil through
refuse or compost decomposition may improve soil structure, water
holding capacity, and friability. However, to increase the
quantity of stable soil organic matter would require large and
frequent refuse applications.
48
-------
Applications of compost generally would: 1) increase the
water holding capacity, while decreasing the bulk density and
compression strength of coarse and medium-textured soils (72,
73); 2) increase aeration of heavy textured soils and allow
easier tillage (74). Bengtson and Cornette (18) presented data
on application of municipal compost at 44 t /ha (19.6 tons/ac)
to a sandy soil planted to slash pine. The application increased
the amount of moisture and extended the period of moisture
availability to the trees during a drought occurring soon
after treatment.
The effect of industrial organic sludge on soil physical
properties is, in many ways, similar to the effect of sewage
sludge application. Epstein (75) reported that incorporation of
5 percent (dry weight) sewage sludge into a Beltsville silt loam
soil initially increased the saturated hydraulic conductivity.
However, after 50 to 80 days the hydraulic conductivity
decreased to that of the original soil due to clogging of soil
pores by microbial decomposition and biomass. Water stable
aggregates averaged 28 to 35 percent for the sludge-amended
soil, as compared to 17 percent for the original soil. The
increase in aggregate stability should result in a more stable
soil structure, since aggregates are more resistant to disinte-
gration by water and the disintegrated material is less apt to
fill in the pore space. Epstein et al. (76) suggested that
continual application of organic matter (waste) would be neces-
sary to maintain this structure as the cementing agents
are decomposed.
Industrial wastewater and sludge often contain significant
amounts of soluble salts. Wastewaters from fruit and vegetable
peeling processes contain high concentrations of sodium (25).
These concentrations (with sodium adsorption ratios greater
than 10) are known to deteriorate soil structure by causing
swelling of the soil and subsequent reduction in permeability (77)
In summary, land cultivation of municipal solid waste or
organic industrial wastes generally results in increased water
holding capacity and improved soil structure (except for wastes
containing high levels of sodium). It also results in some
degree of erosion control. The effects of waste application on
soil physical properties appear short lived; large and frequent
applications may be necessary to maintain these effects.
CHEMICAL PROPERTIES
When municipal compost was applied at rates of 164 and
325 t/ha (73 to 145 tons/ac) to a Mountview silt loam soil over
a 2-yr period, there was an increase in soil organic matter
content, pH, and potassium, calcium, magnesium, and zinc levels
(73). In a greenhouse study, with compost applied at rates of
128 and 512 t/ha (57 to 228 tons/ac) to a Leon fine sand, there
49
-------
was an increase in extractable phosphorus, potassium, calcium,
magnesium, soluble salts, and cation exchange capacity (72).
Similar results were reported when compost was applied at a rate
of 44 t/ha (19.6 tons/ac) to a sandy soil planted to slash
pine (18).
When a highly carbonaceous material, such as municipal
refuse or compost, is incorporated into the soil, the inorganic
nitrogen (primarily ammonium and nitrate) in the waste and the
soil is immobilized by the soil microorganisms. This is pri-
marily due to the enhanced microbiological activity and the
incorporation of nitrogen in microbial cells (77). As the
decomposition proceeds, the C/N ratio narrows, and inorganic
nitrogen may eventually be released. Addition of nitrogen ferti-
lizer is usually necessary to accelerate waste decomposition and
eliminate nitrogen deficiencies in crops (13, 73).
In one study, application of shredded refuse increased the
extractable zinc, iron, manganese, copper, boron, calcium,
magnesium, sodium, potassium, and electrical conductivity of a
Sagehill loamy sand (14). In another study, King et al. (15)
observed increases in plant-available potassium and electrical
conductivity when refuse was applied to a Guelph loam.
Large applications of shredded waste materials could create
anaerobic zones, resulting in greater mobility for certain ele-
ments, such as iron and manganese. Ammonia accumulations have
been observed in anaerobic layers of municipal waste treated
soil (15).
Epstein et al. (76) reported that sewage sludge applied at
rates of up to 240 t/ha (107 tons/ac) greatly increased the CEC,
salinity, chloride, and available phosphorus levels in a
Woodstown silt loam. Also increased were total nitrogen levels
in soil, which were significantly higher after the 160 and 240
t/ha (71 and 107 tons/ac) treatments than in the control.
Nitrate-nitrogen levels were highest at the 15- to 20-cm
(6- to 8-in) soil depth, but decreased sharply below this level.
In an incubation study, air-dry tomato waste was mixed with
a Yolo sandy loam soil at rates up to an equivalent of 1,792
t/ha (800 tons/ac) and incubated at field capacity over 32 wk
(Flocker, personal communication). Soil pH, soluble salt
content, organic carbon, and total nitrogen were significantly
increased as the application rate increased. Concentrations of
sodium and potassium also increased with waste application.
Nitrate-nitrogen, phosphate, and sulfate accumulated slowly
w i t h t i m e.
A refractory metals processing waste was applied at rates
of 11.2 to 112 t/ha (5 to 50 tons/ac) to a Dayton silty clay
loam. The soil pH, soluble salts, extractable calcium, magnesium,
50
-------
ammoniurn-N, zinc, nickel, sulfur, fluoride, and the total
zirconium, hafnium, and lead contents of the soil all increased
(78). The extractable iron, manganese, and phosphorus levels
decreased, according to an examination of percolation water
from columns of waste treated soil. Poison (79) noted that
fluoride from the waste might be more mobile than anticipated.
Incorporation of crude oil into soil increased the concen-
trations of organic carbon, total nitrogen, ancj exchangeable
potassium, iron, and manganese, but decreased the extractable
phosphorus, nitrate-N, and exchangeable calcium (80).
The redox potential (Eh) of soils saturated with natural
gas was lower than that of surrounding soils (81). Adams and
Ellis (82) found that natural gas-saturated soils were in a
highly reduced condition as compared with adjacent soils. The
effects of low Eh on the chemical properties of soil include
increased availability and mobility of some trace elements.
These effects, as well as related impacts on the growth of
vegetation, can be significant in land cultivating oily wastes.
When wastewaters from food processing industries are applied
at rates that create anaerobic conditions, there is also an
increase in the availability of elements such as iron and
manganese.
In summary, land cultivation of municipal solid waste
results in immobilization of inorganic nitrogen by soil micro-
organisms. Thus, addition of nitrogen fertilizer is usually
necessary to prevent nitrogen deficiency in plants. The heavy
metal and nutrient contents of municipal solid waste are low;
therefore, incorporation of such waste into soil would generally
be insignificant in terms of heavy metal enrichment and leaching
of plant nutrients to groundwater. However, land cultivation of
municipal refuse is significant in terms of increasing soil pH,
cation exchange capacity, and the availability of some plant
nutrients, as well as toxicants in the soil. These changes
appear to be of short duration.
Land cultivation of industrial wastewaters and sludges
alters some chemical soil properties. The extent of this
alteration is dependent on the chemical composition, the C/N
ratio, pH, and Eh of the waste, and on the soil type. The pH
of the amended soil is a dominant factor in determining the
mobility and solubility of many contaminants and plant nutrients
MICROBIOLOGICAL PROPERTIES
Municipal solid waste, sewage sludge, and some industrial
sludges (oily waste, pulping sludge, fermentation sludge, etc.)
contain large quantities of readily decomposable carbonaceous
material. Additions of these wastes to soil should cause large
increases in microbiological activity.
51
-------
Municipal refuse has a C/N ratio of about 65:1 (14, 15),
and the surface soil generally has a C/N ratio of about 12:1
(77). When wastes with a large C/N ratio (>20:1) are added to
a soil, there is a rapid increase in microbial activity with the
evolution of carbon dioxide (Figure 3). During the initial
decomposition, inorganic nitrogen is immobilized and incorporated
into the new microbial cells, as shown in the left shaded area
under the top curve of Figure 3. As decomposition proceeds, the
C/N ratio of the amended soil narrows, and the energy supply
(carbon) diminishes. Some of the microbial population dies
because of the decreased food supply, and ultimately a new
equilibrium is reached. The attainment of this new equilibrium
is accompanied by the release of inorganic (available) nitrogen.
The level of stable organic matter or humus may be increased,
depending on the quantity and type of waste added. The time
required for this decomposition cycle depends on the quantity
of organic matter added, the supply of utilized nitrogen, the
resistance of the organic waste constituents to microbial
activity, temperature, and moisture levels in the soil (77).
When composted municipal refuse and sewage sludge were
mixed with an Arrendondo fine sand, Rothwell and Hortenstine (78)
observed an initial rapid increase in the bacterial population,
which subsided rapidly after 6 days. However, the fungal
population of the treated soil increased at each measurement
period throughout the 26-day testing period.
Hunt et al. (83) reported that addition of refuse compost
at rates of 8.1 to 32.3 t/ha (3.6 to 14.4 tons/ac) to a sandy
soil decreased parasitic spiral nematodes and increased sapro-
phagous nematodes. Parasitic ring nematodes were not affected.
Cottrell (13) and Halverson (14) observed that paper
products were converted to indistinguishable brown organic
materials 10 mo after application of municipal shredded refuse
to a sandy soil in eastern Oregon. After one full growing
season, essentially no paper products remained, and only resis-
tant materials existed from the initial refuse application of
896 t/ha (400 tons/ac).
Climatic conditions affect microbial decomposition of
wastes. King et al. (15) reported that refuse decomposition
due to microbial activity was retarded by cool temperatures
and by soil saturation from snow accumulation in the winter
months. Soil saturation establishes anaerobic conditions,
resulting in slower decomposition than would be experienced
under aerobic conditions.
Municipal refuse applied to acid strip mine spoils in West
Virginia decomposed rapidly even though the soil pH was from
3.7 to 4.4 (84). This decomposition was probably caused by
acid-tolerant soil fungi.
52
-------
80-
60-
C/N
RATIO 40-
20-
NET IMMOBILIZATION
':. Y,^x!:t:.^'-
^f.-:^-,/--.;:'^-:.:
'f'-tt'-'iv,. '':
Q-i±ZiM±
on
CO
AMOUNT
NET MINERALIZATION
NE\V
NO^ LEVEL
TIME
Figure 3. Changes in C/N ratio and nitrate levels of soil during
microbial decomposition of a highly carbonaceous waste
material (77).
-------
Literature on the microbial assimilation of petroleum and
its products is voluminous (27, 81, 82, 85, 86, 87). Over 100
species of bacteria, yeast, and fungi representing 31 genera
have been reported to attack one or more types of petroleum
hydrocarbons (85).
The initial effect of even minimal oil contamination is to
lower microbial population and carbon dioxide.production or C/N
ratio (85, 86). Following this "shock" period (a few weeks to
several months), there is generally a stimulation in microbial
growth and shift in the relative abundance of different species
of organisms. The increasing number of organisms in the contami-
nated soil is a good indication of a rapid breakdown of oil,
which occurs if the soil is supplied with enough nitrogen and
deficient minerals such as phosphorus (86).
In land cultivation, the waste may not be evenly distributed
through the plow depth; therefore, zones of unusually high waste
concentration may exist. Some of the contaminants or constituents
in the waste can destroy soil microorganisms or suppress their
activities, if present in excessive amounts. Parr (88) has
reviewed the inhibiting effects of a large number of chemicals
on microorganisms and their transformations in soil. Fungicides
and fumigants, for example, function as partial soil sterilants,
destroying pathogenic as well as saprophytic organisms, including
those responsible for ammonification and nitrification.
In summary, microbial decomposition of the organic components
of both municipal solid waste and industrial wastes does occur.
The large soil microbial population, however, may require very
specific substrate, energy sources, and environmental conditions
to achieve the maximum rate of waste degradation. Waste contain-
ing high levels of certain toxic constituents (e.g., pesticides)
may destroy soil microorganisms or suppress their activities.
54
-------
SECTION 7
EFFECTS OF WASTE APPLICATION ON
PLANT GROWTH AND ELEMENTAL UPTAKE
Various studies have been conducted on the growth and
elemental uptake of crops grown on soils amended with municipal
solid waste or industrial wastes. These studies, however, have
been limited to greenhouse and small-scale field experiments.
Published literature on vegetative impacts from land cultivation
of industrial wastes is particularly scarce. Most land culti-
vation sites are designed for disposal only; crops are not
generally grown for human or animal consumption.
MUNICIPAL SOLID WASTE
In a field study conducted to evaluate the effect of land
disposal of shredded municipal waste on plant growth and nutrient
uptake, the waste was applied at rates up to 896 t/ha (400 tons/ac)
to a Sagehill loamy sand (13). Alfalfa and tall fescue yields of
11.2 to 13.4 t/ha (5 to 6 tons/ac) were produced during the first
growing season at refuse application rates of 0 to 448 t/ha
(0 to 200 tons/ac) and addition of nitrogen fertilizer at 448 to
1,120 kg/ha (400 to 1,000 Ib/ac), respectively. Plant contents
of nitrogen, phosphorus, sulfur, calcium, magnesium, potassium,
iron, cobalt, copper, and chromium were not affected by the addi-
tion of waste. However, manganese and zinc uptake by wheat,
fescue, and alfalfa increased with waste addition and with nitro-
gen fertilization. At 448 t/ha (200 tons/ac), boron uptake by
wheat and fescue plants exceeded phytotoxic levels. Molybdenum
uptake by alfalfa grown with higher application rates reached
levels potentially hazardous to livestock during the first grow-
ing season, but decreased to normal levels during the second year.
King et al.(15) reported that applications of municipal
refuse at rates of 188 to 376 t/ha (85 to 170 tons/ac) and liquid
sewage sludge at 2.3 to 4.6 cm (0.9 to 1.8 in) to an agricultural
loam soil (pH 7.6) resulted in no significant differences in
yields of rye and corn as compared to the controls. In this
study, levels of zinc, copper, cadmium, and lead of rye and corn
plants usually increased with waste addition but were below
levels considered toxic to the crops or to animals that might
consume the crops.
Steigerwald and Springer (89) conducted a 3-yr, large-scale
field trial using fresh municipal solid waste, composted solid
55
-------
waste, and a compost of solid waste and digested sewage sludge.
Climatic conditions, soil type, application rates, and plant
species were not given. In the study, plant yields were strongly
influenced by the type of waste added to the soil, with solid
waste producing the smallest yield increases and the refuse and
sludge compost the largest. For plants that thrive on solid
waste (e.g., corn and tomatoes), yields were increased 20 per-
cent or more the year refuse was applied. Plants sensitive to
solid wastes (e.g., beans) reacted with reduced yields, but
this impact could be somewhat alleviated by heavy watering to
leach soluble salts and boron out of- the root zone. However,
this could result in surface or groundwater contamination. Better
results were achieved with fresh solid waste applied during the
fall. Solid waste compost provided higher yields than did fresh
solid waste. Those plants that thirve on solid waste recorded
yield increases of about 20 percent when the refuse/sludge
compost was applied to the soil. All plants recorded yield
increases of about 45 percent with compost application, the
increases depending on the application rate. Better results were
obtained with this compost when it was applied in the spring.
In a 9-yr experiment in Germany (90), ground fresh and
composted refuse were applied to a silty sand (pH 5.8) at the
rate of 99.7 t/ha (44.5 tons/ac) at the beginning of a 3-yr
rotation, and at 89.6 t/ha (40.0 tons/ac) at the beginning of
the second and third 3-yr rotations. The rotation crops were
potatoes, rye, and oats. Supplemental chemical fertilizer
(incremental amounts of nitrogen and constant amounts of phos-
phorus and potassium) was applied each year. In the first year,
composted refuse increased potato yields whije the fresh refuse
reduced yields, probably due to nitrogen deficiency. In the
succeeding 2 yr, following stabilization of the fresh refuse in
the soil, however, the yields of rye and oats on the fresh refuse
plots were increased over yields .on both the composted refuse
plots and on the control plots of* equivalent chemical fertili-
zation. For the total 9 yr of experimentation, yields were 11.1
percent higher with the composted refuse and 11.7 percent higher
with fresh refuse than were the yields from the control plots
receiving equivalent amounts of chemical fertilizers.
Over the past few years, numerous reports have been pub-
lished on the incorporation of composted refuse into soil and
its effect on crop yield and quality. Yields of Bermuda grass,
sorghum, and corn increased with applications of 80, 143, and
112 t/ha (36, 64, and 50 tons/ac), respectively, of composted
municipal refuse and sewage sludge (73). These yields, however,
were surpassed by fertilizer application rates of 180 kg/ha
(161 lb/ac) of nitrogen together with adequate phosphorus
and potassium.
Hortenstine and Rothwell (72) reported that yields and the
nitrogen, phosphorus, and potassium contents of oats increased
56
-------
greatly when compost was applied to a Leon fine sand at a rate
of 521 t/ha (233 tons/ac). Radishes showed a similar response
except for indications of phytotoxic effects at the 521-t/ha
(233-tons/ac) compost application rate. Pelletized municipal
refuse compost as a soil amendment and nutrient source increased
sorghum yields even at the highest rate (64 t/ha, or 29 tons/ac)
of applied compost (7).
Composted refuse increased the uptake of most plant nutrients
(7, 91) except in cases where a nutrient might have already been
present in adequate amounts (73). This increase was caused by
changes in soil pH and water holding capacity due to compost
application plus the small nutrient addition. Nitrogen was the
only nutrient for which the uptake by plants was reduced by the
addition of composted refuse (91). The decrease in nitrogen
uptake probably resulted from an initial immobilization of
nitrogen by soil microorganisms.
The sodium concentration of the newsprint component of refuse
was high, but compost application had relatively little effect on
sodium concentration in sorghum except at the very high rates (73).
Zinc and copper concentrations were increased by both compost and
nitrogen additions. Soil and plant tissue tests indicated that
zinc could accumulate in potentially toxic amounts if the compost
was applied at rates totaling several hundred metric tons per
hectare over a few years.
Phytotoxic effects of boron in dwarf beans were observed as
a result of the application of 100 t/ha (45 Ib/ac) of municipal
compost to light stony soil (92). Leaching the compost to
decrease the boron concentration prior to application eliminated
the phytotoxic effects and significantly increased the fresh
weight yield of the total bean plants.
In summary, although various methods of waste disposal have
been practiced for centuries, application of municipal refuse
to agricultural land to improve soils and crop production as well
as to dispose of the waste material is relatively new. Various
investigators have applied municipal refuse or compost to
marginal and agricultural lands and have found generally increased
yields of many different crops. Some instances of decreased crop
yields due to waste applications were also reported. In these
cases, application rates were very high, and phytotoxicities were
due to high concentrations of soluble salts and some elemental
constituents of the waste such as boron, zinc, or copper.
The nitrogen content in the municipal refuse or compost is
low and not readily available to the plant. Nitrogen deficiency
usually occurs as a result of application of these waste materials
to soil. Addition of nitrogen fertilizer to the waste-amended
soil would increase plant growth, which should enhance plant up-
take of both nutrients and toxic metals.
57
-------
INDUSTRIAL SLUDGES
Baker (93) has made an extensive review of the effects of
oils on plants. Oils vary in their toxicity according to the
content of low-boiling compounds, unsaturated compounds, aro-
matics, and acids. The toxicity is in the following order:
aromatics>olefins>naphthenes>paraffins. Within each series of
hydrocarbons, the smaller molecules are more toxic than the
larger ones. The effects of oil coating on physiological
processes were summarized:
Plant surfaces are readily wetted by petroleum oils.
Cell membranes are damaged by penetration of hydro-
carbon molecules, leading to leakage of cell contents;
thus oil may enter the cells.
Oils reduce transpiration rate, probably by blocking
stomata and intercellular spaces. Oils also reduce
photosynthetic rate by disruption of chloroplast
membranes and resulting accumulation of end-products
brought about by inhibition of outward translocation
from the leaf.
The effects of oils on respiration are variable, but
an increase of respiration rate often occurs, possibly
due to mitochondrial damage, resulting in an
"uncoupling" effect.
t Oils inhibit nutrient translocation, probably through
a physical interference with the transport mechanism.
Oils inhibit germination, probably resulting from oil
entering the seed and killing the embryo, or from
oil coating the seed and preventing the oxygen and
water uptake essential for germination.
The severity of the above effects depends on the constituents
and amount of the oil, the environmental conditions, and the
species of plant.
Several workers have reported that fresh oils are more toxic
to plants than weathered oily waste materials (94, 95). One must
assume the decrease in toxicity is a function of volatilization
of the lighter molecular weight compounds present in the oily
waste. Lighter weight oil also generally has more leaf penetrat-
ing capacity than do more viscous oils and thus has a higher
probability of toxicity to a plant (96).
Toxicity of an oil to a plant often depends upon a parti-
cular plant characteristic. For example, increased oil retention
caused by pubescence, leaf angle, and the presence of a surfactant
may increase plant toxicity (93). Other plant properties, which
58
-------
decrease oil toxicity would include heavy cuticles, low frequency
of stomata, and stomata located only on the underside of a leaf.
Currier and Peoples (97) have reported that barley and carrot
roots were more resistant to hydrocarbons than the leaf portions
of a plant. This resistance may be expected because of the
existence of stomata in the plant leaf, the uptake of more polar
compounds by plant roots, and the effect of a soil absorbent
surface as a sink for the hydrocarbon compounds.
The stage of plant growth also affects the interaction
between plants and hydrocarbons. Annual species are most damaged
by summer oil applications. Oil applied during flower bud
formation reduces flowering and oil treated flowers rarely produce
seed (98).
Some of the initial work on interactions between plants and
oily wastes were conducted by Carr, where he applied oil to soils
at a rate up to 4 percent by weight (99). Carr observed that soy-
bean growth was enhanced at approximately 1 percent oil appli-
cation but the growth was markedly reduced at rates greater than
1 percent. Udo and Fayemi (80) observed marked reduction in
germination of maize upon applications of oil exceeding 2 percent
by weight.
Murphy (100) reported that oil applied at a rate of
23,400 1/ha (2,500 gal/ac) or more and mixed with the surface
10 cm (4 in) of soils essentially inhibited all wheat seed
germination. With mixing, oil applied at a rate of 4,670 1/ha
(500 gal/ac) did allow approximately 80 percent wheat seed
germination. However, when crude oil was applied to the soil
surface without mixing, delayed wheat seed germination was
observed at the 23,400 1/ha (2,500 gal/ac) rate, but normal
germination occurred with application of only 6,570 1/ha
(500 gal/ac). Addition of 46,700 1 or 140,100 1 (5,000 or
15,000 gal) of crude oil per ha essentially eliminated germination,
When oil was applied and covered with 10 cm (4 in) of soil, which
would be similar to a subsurface injection of oily waste material,
seedling germination was delayed at the higher application rates
but no effect was seen on the percentage germination up to 46,700
1/ha (5,000 gal/ac). The wheat seed were planted at 3.8 cm
(1.5 in) deep.
Although numerous studies have been completed on the effect
of spray oils on plant growth, very few studies have been
completed with objectives related to land application of oily
waste disposal and the resultant effect on plant growth. Plice
(81) studied the growth of cotton, sorghum, soybean, and field
peas after application of a paraffin base, an asphalt base, and
a basic sediment at rates of 0.1, 0.5, and 1 percent. He
summarized his results to indicate that crop yields decreased by
14, 39, and 58 percent with applications of oil at rates of
0.1, 0.5, and 1.0 percent, respectively.
59
-------
Raymond et al. (87) applied crankcase oils, crude oils,
heating oil, and heavy fuel oil at 39,200 1/ha (100 bbl/ac) to
soils at three locations and planted a variety of vegetables 9 mo
after soil incorporation. Results, though incomplete and
variable, showed that at one location, radish and garden pea
seeds germinated, but very few survived to grow into normal
plants. At another location, normal growth of both turnips or
beans was observed in almost every treated plot. Concentrations
of lead in beans and turnips were significantly higher with
crankcase oil application, reaching 13 and 14 ppm, respectively,
as compared to 8 and 3 ppm in the control plots.
Giddens (101) conducted field and greenhouse experiments
to determine the effects of application of spent motor oil on
soil properties and plant growth. At oil rates of up to 31,100
1/ha (3,320 gal/ac), peanuts, cotton, soybeans, and corn were
successfully grown when amply fertilized, especially with
nitrogen. Growth of sorghum and weeds was significantly reduced
by high oil rates. Corn grown on recently oil-treated soil
contained lower concentrations of nitrogen and manganese but the
same concentrations of phosphorus, potassium, calcium, magnesium,
and lead as plants grown on untreated soil. Previous oil appli-
cation increased the manganese and zinc contents of corn tissue,
but no toxicity symptoms were observed.
In a greenhouse experiment (80), crude oil was applied at
rates of 0 to 10.6 percent by weight to a tropical soil, and
three corn crops were raised in succession in the same soil.
With crude oil applications at 4.2 percent (soil weight), germi-
nation and yield were reduced 50 percent and 92 percent,
respectively. The poor growth was attributed to suffocation of
the plants, interference with plant/soil/water relationships,
and toxicity from sulfides and excess available manganese
produced by anaerobic conditions during the decomposition of
the hydrocarbons.
DeRoo (102) evaluated mycelial sludges produced by the
pharmaceutical industry in Connecticut as a nitrogen fertilizer
and an organic soil amendment. Application of the sludges at
rates of 12, 36, and 108 t/ha (5.4, 16, and 48 tons/ac, wet
weight) to a Windsor loamy sand in the greenhouse retarded
early growth of tomato plants; corn growth was stunted only at
the 108-t/ha (48-tons/ac) rate. Field studies showed that
tobacco did not benefit from mycelial residues applied at rates
equal to the organic nitrogen in a standard commercial tobacco
fertilizer mix, and that the overall response of corn to an'
addition of 224 t/ha (100 tons/ac) of mycelial residues was
favorable. He concluded that if those wastes were applied
repeatedly at high rates to the same field, the soluble salt
and high zinc content in the sludges might injure the plants.
60
-------
Studies with similar objectives have been conducted using
lagoon pulp sludge (Jacobs, personal communication) and nylon
processing sludge (Cotnoir, personal communication). Results
indicated that the sludges would have value as a low-analysis
nitrogen fertilizer under proper crop management. Growth of
corn and wheat was normal, and no significant uptake of heavy
metals as a result of sludge treatment was noted.
In a field experiment at Santa Clara, California, cannery
fruit sludge was applied to a marginal Willow clay soil at rates
of 0 to 1,952 t/ha (871 tons/ac) fresh weight (103). Dry matter
yields of the wheat plants increased with increased amounts of
waste applied, because of plant nutrients in the waste material.
A fourfold increase of forage yields over the control was noted
for barley and vetch as a result of application of cannery waste
to a marginal land near Gilroy, California (Flocker, personal
communication).
In a field study (79), the effect of a refractory metal
processing waste slurry on perennial ryegrass forage quality
and seed yield was investigated. Results showed that perennial
ryegrass dry matter yields were not significantly changed by
waste additions up to 112 t/ha (50 tons/ac), and were similar
to yields obtained in commercial farm operations. Seed yields
were slightly less than normal, but seed viability was not
affected by the application. In this study, of the 20 elements
analyzed, 17 were not significantly affected by waste applica-
tion. The remainder - sulfur, sodium, and nitrogen - showed
significant increase in uptake by the ryegrass at the 112-t/ha
(50-tons/ac) rate as compared to the control plots.
Nelson (personal communication) observed a distinctly
stunted growth of corn, soybeans, and wheat on a soil that
received heavy applications (up to 20 cm thick) of a steel mill
sludge. The stunted growth was attributed to: 1) phosphorus
deficiency resulting from phosphorus fixation by iron oxides
in the sludge, 2) nitrogen deficiency due to microbial immobili-
zation during decomposition of the sludge, and 3) poor root
development as a result of compaction of the soil sludge mix-
ture. However, trace elements did not accumulate in plants.
In summary, there has been some evidence of adverse effects
caused by land cultivation of industrial wastes on germination,
growth, and metal uptake by crops, particularly when the soil
is not adequately fertilized. Nitrogen often appears to be the
limiting nutrient when industrial wastes, especially carbonaceous
ones, are applied. Phosphorus is also a limiting factor when
metal processing or steel mill sludges that are high in iron
and manganese oxides are land cultivated.
There has been relatively little research on evaluation of
yield and quality of crops that are grown on soils treated with
61
-------
industrial sludges. Generally, unless the waste to be deposited
on land is considered either harmless or a nutrient source and/or
soil amendment, the disposal area is generally devoid of any
purposely seeded crop. Wild grasses and weeds are relatively
common at many industrial waste land cultivation sites.
62
-------
SECTION 8
REGULATIONS AFFECTING LAND CULTIVATION
With the passage of the Resource Conservation and Recovery
Act of 1976 (PL 94-580) on October 21, 1976, the U.S. Environ-
mental Protection Agency (EPA) was given its first solid waste
regulatory responsibility. This responsibility applies only to
the management of hazardous wastes and requires that EPA develop
standards applicable to generators, transporters, and disposal
facilities.
The specific standards developed for hazardous waste dis-
posal facilities will determine the impact of federal regulations
on disposal of waste materials by land cultivation. Thus, land
cultivation of hazardous wastes may be influenced in the future
by federal regulations. For other wastes, regulatory responsi-
bility rests with the states.
State agencies responsible for regulating wastewater/sludge
and solid waste disposal in 32 selected states were contacted
to provide an indication of the impact of state regulations on
land cultivation of municipal solid waste and industrial waste-
waters/sludges. The discussion that follows is based on the
published waste disposal regulations of the 32 states and per-
sonnel. A summary of the relevant regulations in the states
contacted is presented in Table -9 . As shown, 28 states do not
have specific regulations or guidelines for land cultivation.
In these states, land cultivation disposal is evaluated on a
case-by-case basis. Evaluation procedures vary from state to
state, but normally include consideration of the following factors:
Site topography
Depth to groundwater and adjacent surface
water courses
Soil type
Site operating procedures and deactivation plans
Monitoring requirements.
California is one of the 28 states that evaluates land
cultivation sites on a case-by-case basis. Table 10 summarizes
the requirements imposed on one site in the San Francisco Bay
area. The applicants proposed to either surface spread or
subsurface inject alum sludge from water treatment plants.
Requirements shown in Table 10 indicate the type of constraints an
63
-------
TABLE 9 . SUMMARY OF STATE REGULATIONS AFFECTING LAND CULTIVATION
State
Cal iform'a
Connecticut
Delaware
Florida
Pertinent Regulations
There are no specific guidelines or regula-
tions for land cultivation
Spray irrigation guidelines serve as one
reference point in evaluating land cultivation
applications
The state "Water Reclamation Law" dictates
the groundwater quality must be maintained at
sites utilizing land disposal of wastewater
Waste for land cultivation must be biodegra-
dable
Group 1 wastes (hazardous materials) must be
disposed of in Class I disposal sites
There are no specific guidelines or regulations
for land cultivation
Permits are required for all land disposal
operations
There are no specific regulations or guide-
lines for land cultivation
A permit is required for disposal of waste by
land cultivation, just as for any other
disposal methods
Review of land cultivation permit applications
concentrates on waste characteristics and site
characteristics such as soil types and depth
to groundwater
There are no specific guidelines or regulations
for land cultivation
Spray irrigation guidelines are used to some
extent as a reference point for nutrient and
hydraulic loading considerations related to
land cultivation disposal sites
(continued)
-------
TABLE 9 (continued)
State
Pertinent Regulations
Florida (Continued)
Georgia
en
in
Idaho
II1i noi s
Indiana
Substantially different climatic conditions
in different parts of the state make flexible
guidelines attractive
There are no specific guidelines or regula-
tions for land cultivation
Permits are not required for land disposal of
wastewater if there is no surface discharge.
The state reviews plans and specifications to
establish the environmental adequacy of all
waste disposal methods
Regulations governing spray irrigation faci-
lities prevents the use of spraying without
a cover crop
There are no specific regulations or guide-
lines for land cultivation
Specific spray irrigation regulations requiring
that no groundwater mound results and that no
salt intrusion be observed on neighboring
property is also applied to land cultivationof
wastewaters
I There are no specific guidelines or regula-
tions for land cultivation
Permits are required
There are no specific guidelines or regula-
tions for land cultivation
Land cultivation has recently received increased
emphasis due to groundwater pollution problems
which showed up at several sites during
the summer of 1976. These sites had operated
unsuccessfully the previous years.
(continued)
-------
TABLE 9 (continued)
State
Kansas
Pertinent Regulations
There are no specific guidelines or regulations
for land cultivation
Spray irrigation regulations are used for
reference in evaluating land cultivation of
wastewaters
Kentucky
en
en
Mai ne
Maryland
Specific land cultivation guidelines are not
desired since flexibility in matching wastes
and disposal sites is desired. Flexibility is
particularly important due to the widely
varying terrain experienced with the state
Discharge permits are not required for waste-
water land cultivation systems with zero
surface discharge, but construction permits
are required. Provisions also exist for
periodic inspection to ensure proper opera-
tion and zero discharge conditions
There are no specific regulations or guide-
lines for land cultivation
Guidelines are currently being prepared for
disposal of paper mill sludge by land culti-
vation
Guidelines have been written for disposal of
municipal sewage sludge by land cultivation
There are no specific guidelines or regula-
tions with the exception of certain bacterio-
logical standards which have been set for some
food processing wastes
Specific spray irrigation regulations and
sludge disposal guidelines aid in the evalua-
tion of land cultivation sites
(continued)
-------
TABLE 9 (continued)
State
Pertinent Regulations
Massachusetts
Mi ch i gan
en
Mi nnesota
Mississippi
There are no specific guidelines or regula-
tions for land cultivation
Certified sanitary landfill facilities must
be used for disposal of hazardous waste
Land cultivation requires state approval
There are no specific guidelines or regula-
tions but there are specific procedures re-
quired for site investigation prior to grant-
ing a permit for land cultivation; moni-
toring wells are required
Groundwater standards are in the process of
being drafted which will be utilized in
evaluating future land cultivation sites-
All disposal sites will be required to ensure
that the neighboring groundwater meets the
state standards (which basically will be
drinking water standards)
There are no specific regulations or guidelines
for land cultivation
Land cultivation is uncommon except for
food processing wastes
A permit is required from the state for the
operation of land cultivation sites; the
state must approve each type of waste being
disposed at the site
Existing regulations are vague, but there are
plans to write specific guidelines for
various categories of waste such as oily
waste, agricultural waste, etc.
(continued)
-------
TABLE 9 (continued)
State
Pertinent Regulations
New Hampshire
New York
CTl
00
North Carolina
No specific guidelines or regulations currently
exist, but permission to operate a land
cultivation facility is required
Permission is granted based on a view of waste
composition and site soil types, topography
and operating procedures. Permission is
granted on a temporary basis contingent on
successful test plot results. If test plot
application results are successful, a more
permanent permission permit would be issued
There are no specific guidelines or standards
of review for land cultivation disposal
The state policy is to discourage land appli-
cation of toxic waste
Guidelines for spray irrigation are used as
an aid in reviewing land cultivation disposal
application
No specific guidelines have been written for
land cultivation, but specific evaluation
procedures are utilized to evaluate applica-
tions
Applications for use of land cultivation dis-
posal requires that a soil scientist and an
report on the site to
design features and
agronomist review and
determine appropriate
operating procedures
It was indicated that specific regulations
are not desired, since flexibility needs to
be maintained. In this way, a site appropriate
for a specific type of waste can be identi-
fied and utlized
(continued)
-------
TABLE 9 (continued)
State
Pertinent Regulations
Ohio
Oklahoma
cr>
10
Oregon
Pennsylvania
t There are no specific guidelines or regulations
for land cultivation
Land application has received little emphasis
to date since it is used only sparingly
Land cultivation disposal sites are regulated
under the "Controlled Industrial Waste Disposal
Act, 630S Supp. 1976." This establishes
minimum site standards and other factors such
as waste storage capacity. Case-by-case
analysis is still required to evaluate land
cultivation disposal applications
Specific regulatory guidelines were promul-
gated in response to the large quantities of
oily waste requiring disposal (see Table 12)
t There are no specific guidelines or regula-
tions for land cultivation
Specific guidelines for municipal wastewater
treatment, sludge disposal, and/or spray
irrigation are used as a reference point in
evaluating land cultivation applications
There are no specific guidelines or regula-
tions for land cultivation
t Spray irrigation guidelines are used as a
reference for evaluating land cultivation of
wastewater
The general policy is to prohibit land culti-
vation of toxic waste which is not biodegrada-
ble
(continued)
-------
TABLE .9. (continued)
State
Rhode Island
South Caroli na
Tennessee
Texas
Pertinent Regulations
No specific guidelines or regulations for
land cultivation
Off-site disposal of waste requires a permit
Written permission is required if solid
wastes are disposed in any way other than
landfilling
Specific guidelines apply to spray irrigation
disposal facilities
Specific regulations are written for land
farming of cellulosic wastes. Permits are
required
Minimum site criteria have been written for
hazardous waste disposal
Groundwater monitoring of land cultivation
sites is normally required
There are no specific regulations or guide-
lines for land cultivation
All types of disposal facilities are required
to submit plans for approval. Each site must
then obtain an operating registration from
the state. Registration is not granted to a
site unless the operation is determined to be
satis factory.
Hazardous waste management legislation is in
preparation which may have some impact on the
types of waste which may be land cultivated
As a general rule, the state does not approve
disposal of toxic waste by land cultivation
One of the few states which has specific
guidelines for evaluation of land cultivation
disposal applications. However, these guide-
lines are fairly general
(continued)
-------
TABLE 9 (continued)
State
Pertinent Regulations
Texas (Continued)
Vermont
Vi rginia
No permit is required for on-site disposal of
waste. However, it is required that such
waste disposal be recorded in the property
records
The principal focus of the guidelines is to
prevent the buildup of toxic materials in the
soil. A safety margin is provided between
the maximum allowable toxic constituent
concentrations and the level at which these
constituents may become detrimental to soil
productivity (see Table 12).
» There are no guidelines or regulations per-
taining to land cultivation and there are
no specific prohibitions against the use of
this disposal method for industrial waste
i It is state policy to discourage land culti-
vation as a disposal method for industrial
waste other than food processing waste.
Approximately 60 percent of Vermont residents
rely on groundwater for their drinking water
supply, and therefore, are very sensitive to
groundwater pollution potentials arising from
land disposal practices
There are no specific guidelines or regulations
for land cultivation
Site plans are reviewed to insure that surface
and groundwater standards will not be exceeded
> There is a general reluctance to utilize land
cultivation for disposal of toxic or hazardous
waste
(continued)
-------
TABLE 9 (continued)
State
Washi ngton
West Virginia
-j
ro
Wisconsin
Pertinent Regulations
There are no specific guidelines or regula-
tions for land cultivation
State control is exercised principally through
NPDES regulatory system, even for sludges
..Guidelines have been written for spray irriga-
tion facilities, a relevant feature being
that there is a five year limit on spray
irrigation at any one site
There are no specific regulations or guidelines
for land cultivation
Land cultivation is seldom used and has
received little attention
Land spreading of toxic waste is discouraged,
although specific regulations have not been
wri tten
A possible exception to this general policy
would be dilute solution of toxic waste which
are biodegradable
A specific permit program exists governing
spray irrigation- Information gained from
this program can be utilized to help ensure
proper design and operation of land cultivation
sites
-------
TABLE 10. SUMMARY OF REQUIREMENTS .FOR A
LAND CULTIVATION SITE IN CALIFORNIA*
1. Waste Disposal Specifications
Waste disposal shall not cause pollution or a nuisance
Only the applicant's sludges may be disposed at the site
Waste may not be carried from the site into any waters of
the state
No waste shall be cultivated within 100 ft of the nearby
creek or drainage ditch
Discharger shall remove and relocate any wastes dis-
charged in violation of these requirements
Waste disposal shall not degrade the quality of any
usable groundwater
Surface spreading is prohibited when raining or when
soils are saturated
2. Provisions
Discharger must file with the Board a report of any
material change or proposed change in the character,
location or quantity of the waste discharge
The Board must receive notification 90 days prior to
discontinuation of site use, submitting a report of
methods and controls to assure surface water quality
protection during final operations and the proposed
subsequent land use
Property owner has a continuing responsibility to
correct problems arising in the future
t Discharger shall permit the Board: (1) entry to premises
where wastes or records are located, (2) access to copy
records, (3) inspection of monitoring equipment and
records, and (4) to sample any discharge
*Requirements issued by the California Regional Water Quality
Control Board, San Francisco Bay Region. Waste is alum sludge
from water treatment plants.
73
-------
applicant might face; however, variations must be expected. In
general, a case-by-case review can be anticipated to yield
requirements that are site and waste specific. For example,
Indiana imposed the requirement that an applicant use deep
(41 cm) injection to avoid odor problems (see Indiana case
study report in Volume 2).
Texas has specific land cultivation regulations that are
generally applicable to all types of industrial wastewaters/
sludges. The regulations address a number of factors that must
be evaluated in considering a site for land cultivation disposal,
including: soils, topography, climate, surrounding land use,
and groundwater conditions. Similarly, waste composition and
cation exchange capacity (CEC) of the soils at the disposal site
are factors that should be noted in detail to determine the
appropriate waste application rate.
In Oklahoma, land cultivation guidelines are aimed at oily
wastes. The suitability of other types of industrial waste-
waters/sludges for disposal by land cultivation is determined on
a case-by-case basis. Oklahoma's guidelines are similar to those
of Texas, both of which are summarized in Table 11. Oklahoma has
specifically excluded water soluble inorganic wastes, judging
that such wastes are not suitable for land cultivation. A list
of wastes deemed to be amenable to land cultivation is also
given, as follows: API separator sludge, oil storage tank
bottoms, biological waste treatment sludge, process filter clays,
petroleum coke waste, process catalyst, water treatment sludge,
and process water treatment sludge.
Local regulations, except for zoning restrictions, normally
do not affect the use of land cultivation as a disposal technique.
Occasionally, local health officials may require secondary
biological treatment of industrial wastewater.
Although the vast majority of states contacted did not
have specific land cultivation regulations or guidelines, indi-
cations are that several states planned to develop regulations
in the future. Mississippi is currently in the process of
developing specific regulations for land cultivation of differ-
ent types of wastes, such as agricultural and food processing
wastes, and oily materials.
On the other hand, Kentucky has no plans to write regula-
tions and feels that specific regulations are inappropriate
for a variety of reasons. In particular, the belief was
expressed that it is important to have flexibility to match
wastes to appropriate disposal sites, especially in a state with
such widely varying terrain and soil conditions.
Two of the states that have regulations related to land
cultivation are Maine and South Carolina. In both states,
74
-------
TABLE IT. SUMMARY OF TEXAS AND OKLAHOMA LAND CULTIVATION GUIDELINES
Guideline (Suimary Statement)
Item
Texas
Oklahoma
Soils
--4
cn
Topography
t Climate
t Surrounding Land Use
Groundwater Conditions
Haste Restrictions
Application Rates
t Should be deep, prefer high
clay and organic content
and have large surface area
(best soils are classed as
CL, OL, MH, CH and OH under
the Unified Soil Classifica-
tion System)
Prefer surface slopes less
than 5 percent, greater
than 0 percent
High net evaporation, median
mean temperature, moderate
24-hr, 25-yr frequency maxi-
mum rainfall
Sparsely populated, or provide
buffer and locate downwind
from nearby residences
Avoid shallow potable ground-
water. If not possible, pro-
vide vegetative cover, avoid
high application rates, moni-
tor groundwater quality
Hot addressed
0 Minimum waste composition
analysis: Cl, P04, Total N,
Zn, Cu, Hi, As, Ba, Mn, Cr,
Cd, B, Pb, Hg, Se, Na, Mg, Ca
Should be deep, have large total
surface area and have high clay and
organic content (best soils are
classed as CL, OL, MH, CH and OH under
the Unified Soil Classification
System)
Slope should be less than 5 percent,
greater than 0 percent
High net evaporation, median mean
temperature, moderate 24-hr, 50-yr
frequency maximum rainfall
Sparsely populated, or provide
buffer and locate downwind from
nearby residences
Avoid shallow potable groundwater.
If not possible, provide vegetative
cover, avoid high application rates,
rigidly monitor groundwater quality
Water soluble inorganic industrial
wastes should not be land cultivated
Minimum waste composition analysis:
Zn, Cu, N1, As, Ba, Mn, Cr, Cd, B,
Pb, Hg, Se, Na, Mg, Ca, Cl, PO/i,
Total N
(continued)
-------
TABLE 11 (continued)
Guideline (Summary Statement)
Item
Texas
Oklahoma
Application Rates
Determine soil cation exchange
capacity (CEC)
Total metals application over
site life should be less
than 50 percent of CEC of top 1
ft of site's soil
If crop grown and harvested at t
site, total metal application
in 30-yr period should be less
than 5 percent of CEC
Total N applied in waste, less
than 125 Ib /ac/yr
Annual free water applied in
the waste should be less than
annual evaporation rate
Not addressed
Not addressed
Determine soil CEC if any of the
elements in waste composition analysis
above are present
Not addressed
Not addressed
Total N applied in waste, no more
than 125 Ib /ac/yr, or the maximum
amount utilized or assimilated by
vegetative cover
Total free water applied should be no
more than the net evaporation for
time period between applications
Oily waste application rate must be
such that soil-waste mixture contains
no more than 10 percent oil by weight
Recommended application rate for oily
wastes at established (over 6 mo old)
sites:
- 35 bbl oil/ac/mo - without fertilizer
- 60 bbl oil/ac/mo - with fertilizer
(continued)
-------
TABLE IT (continued)
Guideline (Summary Statement)
Item
Operational
Restrictions
Mixing Frequency
Mixing Depth
Texas
Oklahoma
All runoff must be contained
(use dikes or lined control
collection basin) unless
discharge permit is obtained.
Collection basin should con-
tain 25-yr, 24-hr maximum
rainfall
t Soil pH must be maintained at
above 6.5 while the site is
active
Mix waste into soil as soon
as possible
Vegetation for human or animal
consumption must be analyzed
for metals contained in the
waste before feeding
t Not addressed
Not addressed
All runoff must be contained unless
discharge permit is obtained (use
dikes or lined central collection
basin). Collection basin must contain
all site runoff from a 50-yr, 24-hr
maximum rainfall.
Soil pll must be maintained at above
6.5 while site is active
Mix waste into soil as soon as possi-
ble
Vegetation for human or animal con-
sumption must be analyzed for metals
and any elements in the waste which
are known to be concentrated by the
plant species before use or sale
t Dependent on rainfall. Recommended prac-
tice is to mix twice monthly for first 2
months, then once every other month
Sludge should be mixed into soil to
a depth of 6 to 12 in
-------
regulations pertain only to land cultivation of cellulosic waste
materials from the paper and allied products industry. Land
cultivation of other types of waste is evaluated on a case-by-
case basis.
Although specific regulations may not currently affect land
cultivation in most states, state policies may have an impact
on the type of wastes that can be land cultivated. In New York
and Vermont, state policy is to discourage and minimize land
cultivation of wastes other than those from agriculture or
food processing.
78
-------
SECTION 9
SITE SELECTION CONSIDERATIONS
In discussing site selection criteria, one can give only
general principles that apply to wastes from many sources and to
waste management systems that are in common use. Since it is
rare to locate candidate sites that exhibit all the characteris-
tics of an ideal location, the final decision as to whether a
site should or should not be used for land cultivation of a
specific waste almost always represents a compromise. Most sites
can be modified to meet the majority, if not all, of the criteria,
The site selected should be usable on a continuous basis.
GENERAL SELECTION CRITERIA
Seven categories of general site selection criteria can
be developed:
Access
Land use status
Perceived site conditions
Flora and fauna
Climate
Economi cs
Public acceptance.
These categories provide convenient reference points and are not
equally important for all sites.
Access
Access is an important consideration in attempting to locate
a land cultivation site. Site access routes that pass through
or near residential areas, hospitals, schools, and business areas
may be undesirable to citizens because of noise, traffic, and
the potential for accidents and waste spills. The routes should,
instead, pass through industrial and warehouse areas.
Access road alignments, and grades along the routes and
within the land cultivation sites are also important considera-
tions. Grades should not exceed 7 percent to properly accommo-
date loaded waste delivery truck traffic. Steeper grades place
potentially damaging strain on trucks, cause significantly
increased operating noise, and increase the potential for brake
79
-------
failure and subsequent accidents. Roads must be structured for
the anticipated size and weight of waste delivery trucks.
Land Use Status
Land use status relates to the extent that development of a
land cultivation site would conflict with use and value of pre-
sent and future on-site and adjacent property. Potential sites
located on or adjacent to areas used or proposed for parks, play-
grounds, open space, and wildlife preserves may be unsuitable
unless site management is very well planned and executed.
Adjacent property may experience a temporary decline in property
value during the period of waste disposal activities. However,
land cultivation of some organic wastes in an agricultural area
may renovate marginal soil for future farming, ultimately increas-
ing its value.
Potential cultivation sites must also be compatible with
county zoning and land use requirements. Areas set aside for
residential use in the near future, for example, would make
unlikely land cultivation sites.
Cultivation operations should be evaluated before startup
to minimize odor, dust, noise, and unsightliness for nearby
property owners. Screening can be provided by natural topography
or vegetation, as well as by man-made barriers or planted
vegetation. Use of uncultivated buffer zones around the site
perimeter may also be necessary if there are nearby residential
or commercial areas.
Another consideration for site selection should be the
potential for historical or archaeological finds in previously
undisturbed areas. Information on this potential may be readily
available from local historical societies, probability maps for
archaeological finds, and other sources.
Site operations in the vicinity of utilities may create
problems. For instance, high voltage power lines can be subject
to short circuiting and loss of power transmission efficiency
in the presence of dust and high humidity. Dust will normally
be a major consideration only while mixing a dried waste into the
soil, or when disking a field after the applied sludge has had
time to dry. Underground water, gas, petroleum, and utility
pipelines may require relocation or some other protection measure
to minimize corrosion and/or breakage.
Perceived Site Conditions
Potential land cultivation sites should be selected to pro-
mote an efficient, environmentally safe operation. To this end,
consideration should be given to soil, dust and litter, topo-
graphy, and subsurface hydrology.
80
-------
Soil--
The soil should not be extremely rocky or have large
boulders. These conditions would make cultivation procedures
difficult and cause greater wear on the land cultivation equip-
ment. Soil characteristics for sites that receive municipal
refuse, industrial wastewaters, and industrial sludges are dis-
cussed in Section 10.
Dust and Litter--
Windblown dust and litter can have an adverse effect on
inhabitants living in the vicinity of a prospective site. Blow-
ing dust is aesthetically displeasing and may carry hazardous
components of some cultivated waste to inhabited areas. Also,
as mentioned earlier, dust, when combined with high humidity,
can short circuit the insulating system of high voltage power
lines. Potential for adverse dust conditions can be anticipated
by familiarization with local prevailing wind conditions, the
type of waste to be disposed, and operating techniques to be
employed at the site.
Land cultivation of municipal solid waste has the greatest
propensity to create dust and litter problems. Industrial
sludges and wastewaters may actually prevent windblown dust,
although disking of a field after applied sludge has dried may
generate dust. In the case of municipal solid waste, a light
application of water or wastewater may control blowing debris and
prevent dust conditions. Water addition may also enhance bio-
degradation processes.
Litter from land cultivated municipal refuse may be unsightly
if not contained. Therefore, prevailing winds should be studied
and mitigating measures applied to avoid spread of litter.
Litter fences, natural barriers, and treelines have been used
with some success to contain refuse litter.
Topography--
Erosion of the land cultivation site due to runoff should be
controlled. Prospective sites should be on relatively level
ground with an average grade of 0 to 5 percent. Grades greater
than 5 percent will significantly increase water velocities with
a subsequent increase in erosion. It is equally important to
avoid standing water on the cultivated soil. Standing water can
create anaerobic conditions and/or excessive leaching of waste
constituents to groundwater supplies. A 1-percent grade should be
sufficient, in most cases, to ensure a noneroding runoff.
The disposal area should be protected by natural or artifi-
cial features (e.g., dikes and berms) to assure protection against
washouts from a 50-yr storm. Washouts can result in the spread
of eroded soils and waste pollutants to adjacent property. The
probability for washouts increases significantly in areas that
include stream beds, gullies, flood plains, etc. Sites located
81
-------
in these areas, therefore, would require costly drainage facili-
ties. It is thus preferable to avoid these areas when considering
potential sites.
In evaluating the suitability of alternative sites, it is
useful to determine the various landforms that could be occupied
by the sites, as shown in Figure 4 (104). The types of land-
forms that can be used for land cultivation sites are:
Upland flat and terrace
Upland crest and valley side.
Upland flat and terrace landforms are generally the most
desirable locations for land cultivation sites. However, suita-
bility of these landforms depends upon site-specific conditions,
including the depth to groundwater and soil characteristics.
Upland flat areas with low permeability and fine-grained soils
are typically preferable. Highly permeable coarse-grained soils
usually underlie terraces, sometimes at very shallow depths.
Thus, if a site is to be located on a terrace landform, there
should be no surface expressions of groundwater nearby. The
likelihood of groundwater intersecting a terrace site increases
as the site position approaches either the valley wall or the
level of the modern floodplains.
Upland crests and valley side landforms are the second most
desirable locations for land cultivation sites. This is because
groundwater usually flows away from these landforms, and because
surface water is limited to incident precipitation and control-
lable off-site runoff, Upland crest and valley side landforms
require the diversion of surface water to reduce the amount of
water entering and possibly infiltrating the site. Except in
very impermeable soils or during extremely wet seasons, ground-
water levels in these landforms should lie well beneath the site.
One drawback to site location in upland crests or valley
sides is that these landforms are often in groundwater recharge
areas. Thus, for each prospective site, the possibility of
groundwater contamination should be investigated in terms of
the soils and hydrology.
Subsurface Hydrology--
Data on groundwater hydrology are useful in evaluating the
potential for contamination at any given site (105). The basic
hydrologic data needed for evaluation are:
Depth to groundwater
Direction of groundwater flow
Water quality characteristics.
The water table typically lies deeper in arid regions than
in humid regions. The depth of the water table tends to change
82
-------
NOTEs NUMBERS DENOTE ORDER OF
PREFERENCE AS LOCATION
OF DISPOSAL SITE.
UPLAND RAVINE
(1)
UPLAND FLAT
(1)
oo
CO
UPLAND VALLEY SIDE
(1)
Figure 4. Relative location of various landforms (104).
-------
with surface topography: it is deeper beneath interstream areas,
shallower in lowlands, and it coincides with the surface of
perennial streams. The water table is usually shallower in
relatively impermeable soils, such as clays, than in relatively
permeable soils, such as coarse sands. In dense, unfractured
rock, the water table may be absent or discontinuous (106).
Data on the direction of groundwater flow is essential.
First, this data helps determine the location of a land culti-
vation site, which should preferably be downstream from a water
supply well. Second, the data is important for accurate instal-
lation of site monitoring wells.
Data on groundwater flow can sometimes be obtained from
records kept by various local agencies. If these records are
incomplete, certain rule of thumb may be used to verify the
direction of flow. One rule is that groundwater moves in
accordance with the hydraulic gradient, from high to low eleva-
tions. With this in mind, an accurate topographic map should
be consulted that shows the site and surrounding area. All
existing wells should be marked on the map. The depth to ground-
water in each well should be noted, and the elevation of the
groundwater surface with respect to sea level calculated.
Approximate contour lines can then be drawn on the map to connect
wells of equal groundwater elevation. The direction of ground-
water flow will be perpendicular to these elevation contour lines.
It may be necessary to drill wells at the candidate sites
to provide supplementary groundwater depth data, or to obtain
subsurface soil and geological information. Any wells drilled
should be cased with PVC pipe for possible future use in the site
monitoring program.
It is generally preferable to locate a land cultivation site
over a brackish or otherwise unusable groundwater than over a
potable water source. Thus, basic information should be gathered
concerning the water quality of underlying site aquifers. This
information establishes baseline quality conditions and is
subsequently useful for determining water quality impacts based
on monitoring data. Information on water quality can usually be
obtained from local health departments and water companies.
Flora and Fauna
A balanced ecology contains a large variety of diverse flora
and fauna, known as a high species diversity. It is best to
locate land cultivation sites in areas with a low species diversity
which do not contain rare or endangered species, or in areas pre-
viously disturbed by man. Thus, operations will not pose hazards
to environmentally significant flora and fauna, such as unique or
endangered species.
84
-------
Climate
Climatic conditions may have a strong impact on the micro-
bial decomposition of cultivated wastes. The biodegradation
rate tends to increase under warm, humid conditions and decrease
under cold, arid conditions. Since the biodegradation rate
strongly affects the allowable waste application rate, land area
requirements are directly affected by the climate. Under warm,
humid conditions, less land is required for a given waste
quantity than under cold, arid conditions.
Economics
Capital and operation and maintenance costs for land culti-
vation sites can vary significantly. These costs are affected
by land availability, soil conditions, topography, waste type,
utility relocations, screening devices, labor rates, and other
factors. For instance, land might be leased at little or no
cost in a case where land cultivation will condition the soil
for future use.
In addition, costs can be affected by the distance required
to transport the waste between the source and the disposal area.
Most municipal and industrial wastes are generated near centers
of population, which can be far from open, low population den-
sity areas where land cultivation might be favorable. The
economic success of land cultivation may hinge on minimizing
waste transport distances.
Pub!ic Acceptance
Public acceptance is of vital importance when selecting a
land cultivation site. If significant public or pressure group
protest is encountered, the selected cultivation area may not be
a practical choice, even though all technical aspects of the
site are ideal. Public attitudes toward land cultivation can
be improved through detailed and carefully organized informa-
tion programs.
Public acceptance is determined, in part, by proximity of
the prospective site to residential areas and/or to areas fre-
quented by the public. When disposal sites are located close
to inhabited areas, common complaints are dust, odor, vectors,
unsightliness, and traffic. In some cases, public opposition
may exist in spite of effective mitigating measures. Therefore,
to ensure success in locating land cultivation sites, it is best
to avoid inhabited areas as much as possible and to design
effective mitigation measures into the site at the project
inception.
85
-------
SPECIFIC SELECTION CRITERIA
Some site selection criteria differ significantly depending
on the characteristics of the waste. In the following sub-
sections, specific criteria will be discussed as they apply to
the three general waste categories addressed. Also discussed
will be sites receiving combinations of waste.
Municipal Solid Haste
Land cultivation of municipal solid waste should most
logically be practiced in areas where waste application improves
soil characteristics. In such areas, refuse may act as a soil
conditioner for cropland or may be used in land reclamation
programs. Cultivation of refuse may increase the cation exchange
capacity and water holding capacity of a sandy soil, increase
the permeability of a clay soil, reduce wind and water erosion,
and provide some micronutrients. Most soil types are amenable
to land cultivation of refuse. Marginal or disturbed land are
especially good candidates for land cultivation of municipal
solid waste. Table 12 is a summary of a few soil limitations
for accepting nontoxic biodegradable sludges and solids.
Industrial Wastewater
Land cultivation and spray irrigation practices for appli-
cation of industrial wastewater are similar. The major differ-
ence is the higher degree of homogeneous mixing and gaseous
exchange in land cultivation, often allowing the wastewater
application rate and quantity applied to be slightly increased.
Specific criteria for selecting land cultivation sites for
industrial wastewater vary, depending on a number of physical and
geochemical parameters. Such* parameters include wastewater
characteristics, wastewater loading, duration of application,
acreage required, local water quality standards, climate, ulti-
mate land use, and seasons of application. The specific site
selection criteria include the following:
Infiltration
Soil thickness
Ion exchange capacity of the soil.
Infiltration--
Wastewater components should remain in the soil's biologi-
cally active zone long enough to be decomposed aerobically. The
time required for aerobic decomposition is largely a function of
waste composition and application rate, and soil characteristics.
At land cultivation sites, fine-textured, unconsolidated
soils are preferred to mechanically weathered bedrock, quarry
wastes, or artificial fills containing diverse waste materials
86
-------
TABLE 12. SOIL LIMITATIONS FOR ACCEPTING NONTOXIC BIODEGRADABLE SLUDGES AND SOLIDS*
00
Item"1"
Permeability of the most
restricting layer above
152 cm
Soil drainage
Runoff
Flooding
Available water capacity
from 0 to 152 cm or to
a limiting layer
Slight
Degree of Soil Limitations
Moderate
Severe
Moderately rapid and
moderate 1.5 to 15 cm/hr
Well drained and
moderately well
drained
None, very slow, and
slow
Soil not flooded
during any part of
the year
>20 cm
Rapid and moderately slow Very rapid, and very
15 to 51 and 0.5 to 1.5 cm/hr slow, >51 and
<0.5 cm/hr
Excessively drained,
poorly drained, and
very poorly drained
Rapid and very rapid
Soil flooded during
some part of the year
Somewhat excessively
drained and somewhat
poorly drained
Medium
7.6 to 20 cm
<7.6 cm
*Modified from a draft guide for use in the Soil Cons. SErv., U.S. Dept. Agr. (107)
tFor definitions see the So-it Saivey Manual, U.S. Dept. Agr. Handbook No. 18, 1951.
-------
and particle sizes (108). Moderately well-drained to well-
drained soils are preferred because they meet both infiltration
and drainage requirements. However, even less well-drained soils
can be considered, provided that wastewater is not being applied
during periods of prolonged rain, heavy rainfall, or freezing
weather.
Hydraulic conductivity values, summarized in Table 13, have
been reported in various sources (104). Soil limitations for
accepting liquid waste are summarized in Table 14.
Soils classified as extremely slow to very slow create
waterlogging and runoff problems at cultivation sites. Soils
classified as slow may require drainage facilities to improve
aeration conditions and prevent erosion. These slowly drained
soils may prove to afford better nutrient and heavy metal removal
than moderate to very rapid soils (108). However, the wastewater
application rates must be considerably lowered with such soils.
Soils in the moderate to rapid class should be ideal for
land cultivation sites. For soils in the very rapid class, flow
rates may be excessive, thus precluding a high degree of waste
renovation. Wastewater must, be retained within the soil profile
for a sufficient period of time to allow the degradation
processes to be effective.
Highly permeable layers of sand and gravel beneath the soil,
which might include fractured bedrock, weathered bedrock, or
cavity systems, allow for little if any additional waste
degradation. Once the wastewater enters a porous media, only
dilution and dispersion should be anticipated. Therefore, the
overlying layer of soil should be deep enough to achieve the
desired degree of biodegradation.
Soil Thickness--
It is generally agreed that a 0.9- to 1.2-m (3- to 4-ft)-
thick soil column should be adequate to provide the degree of
wastewater stabilization required for spray irrigation sites
(108). Since very little is known about soil thickness -
requirements at land cultivation sites, and since there are
similarities between the two techniques, it appears that the
0.9- to 1.2-m soil thickness might apply equally well for land
cultivation sites. This soil thickness estimate assumes that
toxic substances do not exist in the waste or are in such low
concentrations that groundwater quality will not be impaired
if migration from the surface ultimately occurs.
Ion Exhange Capacity of the Soil--
A high cation exchange capacity (CEC) is a desirable soil
characteristic which is related to the levels of organic matter
and clay, as well as types of clay minerals in the soil. CEC
88
-------
TABLE 13. CLASSES OF PERMEABILITY OR PERCOLATION
RATES FOR SATURATED SUBSOILS (104)
Class
Extremely
slow
Very slow
Slow
Hydraulic Conductivity
or Percolation Rate
cm/hr
<0.003
0.003 to 0.025
0.025 to 0.25
Moderate
Rapid
0.25 to 2.5
2.5 to 25.4
Very rapid
>25.4
Comments
So nearly impervious that
leaching process is insig-
nificant. Unsiutable for
wastewater renovation
under most circumstances.
Poor drainage results in
staining; too slow for
artificial drainage. Waste-
water renovation possible
under restricted conditions.
Too slow for favorable air-
water relations and for
deep root development.
Usable under controlled
conditions; drainage faci-
lities may be required;
runoff likely to be a
problem. Good nitrate
removal possible.
Adequate permeability (con-
ductivity). Ideal for most
irrigation systems.
Excellent water-holding
relations and permeability
(conductivity). Ideal for
most irrigation systems.
Application rates may have
to be reduced to ensure
renovation.
Associated with poor water-
holding conditions. Infil-
tration and drainage may
be too rapid to achieve
complete renovation.
Extreme caution required.
89
-------
TABLE 14. SOIL LIMITATIONS FOR ACCEPTING NONTOXIC BIODEGRADABLE LIQUID WASTE*
UD
O
Item1"
Degree of Soil Limitation
Permeability of the most
restricting subsoil hori-
zon to 152 cm
Infiltration
Soil drainage
Runoff
Flooding
Available water capacity
to 152 cm or to a
limiting layer
T#
p**
SIight
Moderate
Severe
Moderately rapid and
moderate 1.5 to 15 cm/hr
Very rapid, rapid,
moderately rapid, and
moderate 0.6 in/hr
Well drained and
moderately well
drained
None, very slow, and
slow
Soil not flooded
during any part of
the year
20 cm
8 cm
Rapid and moderately slow Very rapid, slow,
15 to 51 and 0.5 to 1.5 cm/hr and very slow
>51 and <0.5 cm/hr
Moderately slow
0.5 to 1.5 cm/hr
Somewhat excessively
drained and somewhat
poorly drained
Medium
Soil flooded only during
nongrowing season
Slow and very slow
<0.5 cm/hr
Excessively drained,
poorly drained, and
very poorly drained
Rapid and very rapid
Soil flooded during
growing season
8-20 cm
8 cm
8 cm
*Modified from a draft guide for use in the Soil Cons. Serv., U.S. Dept. Agr. (107).
tpor definitions see the SoU. Swwzy Manual, U.S. Dept. Agr. Handbook No. 18, 1951.
^Temporary installation.
**Permanent installation.
-------
determines the amount of exchangeable waste constituents that
can be retained and stored until assimilated by the biologic
system at a later date. This is particularly important during
periods of peak precipitation in the late fall, winter, and
early spring when the excessively wet soil and cold weather
retard microbial decomposition of the constituents in the
wastewater.
Industrial Sludges--
Land cultivation of industrial sludges is usually performed
primarily as a waste disposal technique. However, depending on
the waste composition, the soils might derive certain benefits
from application of such materials.
In general, the solids content of most industrial sludges
is on the order of 5 percent, meaning that the waste is about
95 percent water. Because of this high water content, the
previously discussed criteria for industrial wastewater are
also applicable to most industrial sludges. Further, these
sludges are often the product of secondary wastewater treatment
facilities that deal solely with industrial effluent. These
industrial sludges are similar to municipal sewage sludges,
although the industrial sludges are normally low in pathogens.
Because of the similarities, existing local criteria and
regulations dealing with the land cultivation of sewage sludges
should be consulted and applied, when appropriate, to site
selection for industrial sludges.
Application of nontoxic biodegradable sludges, such as
cannery waste, requires the same basic site selection criteria
that were previously discussed for municipal solid waste.
Table 13 summarized some of the soil limitations for sludges.
Depth to groundwater for industrial sludge disposal sites should
be in excess of 1.5 m (5 ft), depending on the soil porosity.
When applying sludges as a nutrient soil conditioner to
agricultural land, soil texture is an important consideration.
For disposal of relatively dry wastes, finer textured soils
may be more desirable than sands. There is more available
moisture storage in these soils, which usually contributes to
higher crop yields and higher nutrient removal. In both coarse-
and fine-textured soils, more efficient nutrient utilization is
obtained if the soils are deep and well drained, with no compact
layers to interfere with deep root penetration (109).
Oily wastes and hazardous sludges should be isolated as
much as possible from the surrounding environment. The potential
site, therefore, should have either an impermeable layer
protecting the groundwater, or a deep groundwater table. Oily
wastes are not as great a concern as most hazardous sludges.
No instances have been reported where land cultivated oil debris
has caused groundwater contamination (110). However, a program
91
-------
of soil and groundwater monitoring should be planned
and implemented.
Surface drainage of sites that accept industrial sludges
should be carefully controlled to include:
Drainage diversion of runoff from adjacent property
Control of on-site erosion by level grades or
terracing
Prevention of on-site materials passing to
adjacent property.
Sites Receiving Combinations of Waste
When selecting potential land cultivation sites, it is
important to anticipate receipt of various waste combinations;
the compatibility of different waste types must be thoroughly
evaluated. A site that appears unsuitable for disposal of a
particular waste might be made suitable by combining various
wastes. For example, a prospective site to be used for muni-
cipal refuse might seem unsuitable because of blowing dust and
proximity to an inhabited area. The potential problem could be
solved by application of a compatible wastewater in conjunction
with the refuse. Another example is a prospective wastewater
disposal site with an excessively drained soil. Land cultivation
of a sludge or refuse before wastewater application might
condition the soil by increasing its water-holding capacity. The
wastewater could then be applied after the soil is conditioned
to retain more water.
Land cultivation of an industrial sludge containing a
significant heavy metal concentration requires a soil ph 2 6.5.
If local soils are acidic, land cultivation of this waste is
unacceptable. But if a lime sltidge from a water treatment plant
is available, it may be cultivated in conjunction with the
industrial sludge since the lime sludge will increase the pH.
In summary, site selection requires the following steps:
t Determine waste type and objective of land culti-
vation (i.e., waste utilization or disposal).
t Assess the soil properties and select criteria to
determine the suitability of the soil for receiving
the waste in question. Various guides are available
for rating suitability of soils for receiving many
types of wastes.
Using soil surveys, determine which soils in the
area are suited for receiving wastes.
92
-------
t Locate the suitable soils on the soil map to
determine extent of candidate sites.
Using on-site investigations of soil, geology,
and hydrology, determine the actual suitability
of the candidate site for receiving wastes.
93
-------
SECTION 10
SITE OPERATIONAL CONSIDERATIONS
WASTE TREATMENT
Waste pretreatment or conditioning facilitates handling,
storage, and field operations and detoxifies or removes waste
constituents that may persist in soil and pose environmental
hazards. In some cases, the materials removed can be reused,
but the recycling process may be complex and costly.
Municipal Solid Wastes
Municipal refuse should be shredded prior to land culti-
vation. A nominal size of 5 cm (2 in) has been suggested
(Volk, personal communication) to facilitate handling and soil
incorporation and to reduce breakdowns of equipment due to
jamming of the mixing blades with large pieces of waste
materials. The active operation in Odessa, Texas, however,
shreds refuse to a nominal 10 cm (4 in) size. The magnetic
separator is currently extracting only about 60 percent of the
ferrous metals, which is considerably less than originally
anticipated. No other significant operational problems have
been reported (Schnatterly, personal communication).
Ferrous metals are magnetically separated, while non-
ferrous metals may not be removed due to costs associated with
their separation. The shredded refuse is compacted into trans-
fer trucks and hauled to the site for disposal by land cul-
tivation.
Industrial Wastewaters and Sludges
Current information indicates that industrial wastewater
and sludge are land cultivated as generated, with little or
no pretreatment.
Most industrial wastewaters and sludges presently land
cultivated are generated by the industry's wastewater treatment
plant; as a result, they are similar in many respects to
municipal effluent and sewage sludge. Pathogens and viruses
are usually of little concern when industrial wastes are land
cultivated. However, some industries have combined waste which
94
-------
may contain human waste. Secondary treatment (e.g., activated
sludge) is often employed by the industry, though some in-
dustries _ (e. g. , food processing) use only primary treatment
In some instances, pH adjustment and cooling of wastewater are
also used. If the waste is high in BOD, sodium and soluble
salts, such as those generated by the food processing and
pharmaceutical industries, low application rates or dilution
may be necessary.
Lime sludge generated by a water treatment plant can be
land cultivated directly, although it may require dewatering
by evaporation in a storage pond or pelleting to reduce the
waste volume and field operating costs.
It is speculated that many of the so-called hazardous in-
dustrial wastes may be land cultivated once they have been
pretreated. For example, if a pesticide waste is treated by
a biological or chemical process which alters its formulation
such that it will no longer pose hazards to the environment,
it may be suitable for land cultivation. Such pretreatment may
not be cost effective.
EQUIPMENT AND PERSONNEL REQUIREMENTS
Selection of the proper equipment and personnel is an
important consideration at prospective land cultivation sites.
The quantity and types of equipment and personnel required
depends on the volume and characteristics of waste to be dis-
posed, requirements imposed by regulatory agencies, the land
area of the site, and the need for other duties (e.g., direct
traffic and unloading operations).
Equipment Selection
A wide variety of equipment can be utilized for land
cultivation of waste. Equipment selection depends primarily
on the characteristics of the waste applied and on the con-
straints imposed by regulations. For example, rototillers are
highly adaptable to mixing municipal solid waste with soil,
whereas less expensive disk plows are sufficient for mixing
liquid waste and sludges. Further, tank wagons may be adequate
for surface application of sludge at some locations, whereas
subsurface injection equipment may be required at other
locations by local regulations.
Table 15 lists possible types of equipment suitable for
application of various types of waste. The most frequently
used land cultivation equipment is listed. However, other
related agricultural equipment may be satisfactory to some
extent, especially for sites that handle small quantities of
waste.
95
-------
TABLE 15.* EQUIPMENT CAPABILITY MATRIX
Waste Category
Equipment , RefuseSludgeWastewaters
Rototillers X
Subsurface injection
units X X
Tank wagons -
surface spreading X X
Disks X X
Wheel tractors XX X
Track tractors XX X
Refuse blades X
Earth moving blades X X
Based on greatest adaptability of equipment types according
to case study experience. Many equipment types may be
interchanged with those having a lower degree of suitability.
Rototiller Mixing--
Rototillers, or soil stabilizers, are suitable for mixing
refuse with soil (4). They also may be used to homogenize
liquid and sludge wastes with soil, although disk plows are
usually sufficient for this purpose. Many types of rototillers
are available that will homogenize the refuse with soil in one
pass, although a greater degree of mixing can be accomplished
with multiple passes. Rototillers are usually self-propelled
machines with blades adjustable to a mixing depth of approxi-
mately 46 cm (18 in) in soft soil (Figure 5) and a mixing
width fixed at 2.4 m (8 ft). Figures 6 through 10 show
examples of a few available rototiller varieties.
Maintenance of rototillers used in land cultivating refuse
may be a problem due to the severe operating environment.
Personnel at Odessa, Texas, report that mechanical failures
are a common occurrence with their rototiller, which operates
up to 60 hr/wk. When the rototiller was first obtained, the
operators determined that the front end was too light. A need
was also apparent for equipment to spread the refuse before
mixing with the soil. It was decided to solve both problems
by adding a dozer blade to the front. However, the added
weight of the large blade, plus the load placed on the equip-
ment by requiring it to both spread and mix, has caused frequent
failures of the front suspension and axle. Some failures of
hydraulic pumps and valves have been caused by the very dusty
conditions of operation (Dobbs, personel communication).
96
-------
Figure 5. Mixing tines of Bros rototiller.
JLJl-J*-
Figure 6. Bros mixing.
97
-------
Figure 7. Raygo mixing
Figure 8. Raygo mixing chamber
98
-------
Si,
iii
Figure 9. Koehring rototiller.
- . **»*- *^.. *.*;»" / - *- " ' 7 '
**» -^- -- '-'"*''r'-^ j^i" '.'- *'"' * ?i&i*^x-
~ ******?
Figure 10. Pettibone rototiller
99
-------
Subsurface Injection--
Subsurface Injection may be required for liquid wastes
and sludges that are noxious, highly volatile, or odorous.
Specialized equipment is available that allows injection of
the liquid waste deep enough to minimize air pollution.
Figures 11, 12, 13, and 14 illustrate equipment specifically
designed for subsurface injection. This equipment includes
high flotation tank trucks with special liquid injection plows
attached at the rear which can transport wastes to the culti-
vation site over short distances. Tanks for the trucks are
generally available at 6.1- and 7.6-m3 (1,600- and 2,000-gal)
capacities. Some manufacturers also produce an optional tank
that will hold 13.6 m3 (3,600 gal).
Figure 14 shows another type of unit, which incorporates
a different approach to subsurface injection. The unit is a
track dozer with an injector mounted on the rear. Sludge is
pumped from a storage tank (usually underground) to the in-
jector through a hose that trails the unit (shown in Figure 14)
Flow capacities of 0.6 to 3.8 m3/min (150 to 1,000 gal/min)
are available. The track dozer, used as the prime mover,
requires a power rating of 40 to 60 HP.
In addition to tank trucks and track dozers, a third type
of unit is available. This unit is basically a tractor-drawn
tank wagon with an added injector. Two such tank wagons are
pictured in the case studies, the one used by the Indiana site
for deep (40 cm) injection, and the one used by the Illinois
site for surface spreading. The Illinois operators report that
mechanical failures of the wagon chassis have been a problem.
These failures are primarily due to the extensive use of the
wagons, which is far greater than the average farmer uses such
equipment. To rectify the problem, the operator has strength-
ened the chassis, but some failures still occur.
Surface Spreading--
Equipment used for surface spreading of wastes before
cultivation comprises a variety of transfer vehicles, standard
farm units, and specialized devices. Some of this equipment
includes the following:
Refuse collection vehicles
Refuse transfer trailers
Open bed trucks
Tank trucks
Tank wagons.
Liquid waste is usually effectively applied using spray
nozzles or spray bars.
100
-------
Figure 11. Terra-gator sludge injector
Figure 12. Big Wheels sludge injector
101
-------
F i g u r e 1 3. I.M.E. sludge injector.
Figure 14. Deep Six sludge injector.
102
-------
A wide variety of equipment, produced by many manu-
facturers, is available for surface spreading. Equipment
selection is dependent on waste type and quantity, cultivation
site characteristics, and budget. Figure 15 shows shredded
refuse being unloaded at Odessa, Texas. The equipment being
used is a refuse transfer vehicle. For municipal solid waste,
any easily unloaded vehicle can be employed.
If the waste is a high solids sludge, equipment similar
in design to standard manure spreaders may be used. Figures
16 and 17 illustrate two high flotation trucks with spreader
bodies, which are examples of the type of equipment available.
For small quantities of high solids sludges, tractor-drawn
'farm manure spreaders may be adequate. All major farm
implement manufacturers produce such spreaders.
For wastewaters and low solids sludges, tank trucks or
tank wagons are the logical choice of equipment. Figure 18
shows a high-flotation tank truck equipped with a spray plate
in operation. Figure 19 depicts a typical medium-size tank
truck designed for over-the-road use, which can be used for
surface spreading if the field is firm. This truck may be
equipped with a spray bar, plate, or nozzle. Large tank
trucks, as in Figure 20, can be used if field conditions allow.
The particular vehicle shown in Figure 20 has a capacity of
15 IIH (4,000 gal) and uses a homemade spray bar.
, Conventional farm tank wagons, using a tractor as the
prime mover, can also be employed for surface spreading. This
type of equipment is utilized at the Illinois case study site.
Disk Mixing--
Surface spreading of waste requires a subsequent operation
to mix the wastes with soil. This mixing is necessary to pro-
mote biological degradation by exposing waste to soil and to
produce runoff potential and odors. For refuse, mixing can be
accomplished with disks, but it is preferable to use a roto-
tiller.
Standard agricultural disks used in conjunction with a
tractor or track dozer can efficiently mix liquid waste or
sludge with soil. The size of the disk is dependent on waste
quantity. Large disks are required for large-scale operations
to minimize the time spent mixing, thereby minimizing operating
costs. There are three basic disk types: disk tillers Figure
21), disk plows (Figure 22), and disk harrows (Figure 23).
One or more disk types are produced by most farm implement
manufacturers. Because of their sturdy construction, disks
should perform well for a relatively long time for most land
cultivation operations. However, under highly abrasive
103
-------
Figure 15. Refuse spreader from transfer truck
Figure 16. Terra-gator sludge spreader.
104
-------
Figure 17. Big Wheels sludge spreader
<
Figure 18 . Big Wheels spreader with spray plate.
105
-------
Figure 19. Medium size tank truck capable of surface spreading
*<-*
Figure 20. Large tank truck with spray bar spreading sludge on field,
106
-------
Figure 21. Example of disc tiller,
Figure 22. Example of disc plow,
107
-------
Figure 23. Example of disc harrow.
108
-------
conditions, such as cultivating oily wastes in sandy soil
disks may require more frequent repair and replacement. '
Personnel
Numbers and types of personnel required at a land culti-
vation site are primarily a function of the quantity of waste
input. A minimum of one skilled equipment operator is re-
quired at any site. For small-scale operations, one person
may be able to perform all necessary duties. However, because
of safety considerations, it is desirable to have two or more
persons at the site.
As the size of operation increases, the necessary staff
grows. For small-scale operations, one person may be required
to weigh incoming wastes, direct unloading of wastes at the
proper locations, and maintain records. For large-scale
operations, two persons may be needed for these functions.
If the site operates many pieces of equipment, it may be cost
effective to provide an on-site maintenance staff. For larger
operations, one person will be needed to manage and direct
activities.
WASTE STORAGE
Land cultivation is strongly influenced by local climate.
Field operations are usually curtailed during periods when the
soil is excessively wet or frozen, with the waste stored for
application under more favorable conditions. In addition,
storage is necessary when an equipment breakdown occurs.
It is normally best to provide storage at the treatment
site, so that cultivation activities will not be slowed by
fluctuations in waste generation or transport scheduling. Also,
there is greater public acceptance of storage tanks or lagoons
at the treatment site than at the application site. Aeration
tanks are used for short-term storage of industrial wastewater/
sludge, while storage tanks, ponds, or lagoons are used for
long-term storage. Odors can be a major problem with waste
storage.
In the Odessa operation, cultivation is halted only when
there is a land cultivation or refuse shredding equipment
failure. When this occurs, the refuse is landfilled. Refuse
should be stored after shredding with storage facilities pro-
vided at the shredder or at the land cultivation site.
WASTE LOADINGS AND REAPPLICATION
Optimum waste loadings can be defined in a number of
ways depending on the purpose and frequency of application.
109
-------
The purposes Include erosion control, crop irrigation, ground-
water recharge, nutrient supply, or simply disposal. Applica-
tion frequency depends on available land area, application
rate, waste characteristics, and climate.
Municipal Solid Wastes
In an experimental land cultivation project in Houston,
Texas, optimum application rates are defined by two criteria:
the lowest loading rate that will economically enhance crop
yield; and the highest loading rate that the land can accept
without evidence of environmental damage (Stanford, personal
communication). From the economic point of view, optimum rate
is determined by: 1) cost of soil incorporation; 2) length of
time when the land is not in productive use; and 3) crop growth
and sustenance of high yield (Schnatterly, personal communica-
tion) .
From field and laboratory data on the environmental impacts
including growth of forage crops, a maximum rate of 448 t/ha
(200 tons/ac) per application of municipal refuse on a sandy
soil should not be exceeded (13, 14). Conceivably, the
application rate would be lower on fine-textured soils, pri-
marily because of increased difficulty in mixing the refuse
into the surface soil. In routine disposal currently practiced
at Odessa, Texas, an average rate of approximately 112 t/ha
(50 tons/ac) is used for the one time application.
Information on frequency of application is not available,
but it can be inferred from the degradation rate reported.
Generally, paper products will decompose within 1 to 2 yr,
but more resistant materials such as plastic, some metals, and
rubber fragments remain identifiable for many years (11, 12,
13, 15). Under wel1-aerated, moist, warm soil conditions
and frequent mixing, it appears that a second application of
shredded municipal refuse can be made in 12 to 18 mo. Rates
of decomposition of subsequent waste additions, however, have
not been reported. Thus, the feasibility of yearly application
needs to be determined.
Industrial Wastewaters
Depending on the waste characteristics and the application
system, loadings of industrial wastewater can vary considerably.
Wallace (22) summarized the hydraulic and organic loading rates
used at existing land application sites for industrial waste-
waters (Table 16). He noted that either hydraulic or organic
loading can control in a given instance. In some cases, neither
will be as important as the cation loading, especially with
regard to sodium. For wastewaters with BOD concentrations in
the 1000 mg/1 or less range, hydraulic loading will usually
control.
110
-------
TABLE 16. SUMMARY OF HYDRAULIC AND ORGANIC LOADING RATES USED IN
EXISTING LAND APPLICATION SYSTEMS FOR INDUSTRIAL WASTES*
Type of Waste
Hydraulic Load
Organic Load (BOD)
Biological chemicals
Fermentation beers
Vegetable tanning
Summer
Winter
Wood distillation
Nylon
Yeast water
Insulation board
Hard board
Boardmill Whitewater
Kraft mill effluent
RI**
Semichemical effluent
Paperboard
Deinking
Poultry
Peas and corn
57 day pack
35 day pack
Dairy
Low value
High value
Soup
Steam peel potato
Instant coffee and tea
Citrus
Cooling water - aluminum
casting (RI)
gal/ac/dayt
1,500
1,350
54,000
8,100
6,850
1,700
15,100
14,800
6,000
15,100
14,000
350,000
72,000
7,600
32,400
40,000
49,000
34,400
2,500
30,000
6,750
19,000
5,800
3,100
95,000
i n/wk
0.39
0.35
13.91
2.09
1.76
0.44
3.89
3.81
1.55
3.89
3.61
90.13
18.54
1.96
8.34
10.30
12.62
8.86
0.64
7.73
1.74
4.89
1.49
0.80
24.46
lb/ac/day#
370
170
360
54
310
287
_
138
85
38
26
120
90-210
13-30
108
100
238
2,020
10
1,000
48
80
92
51-346
35
* Summarized by Wallace (22)
3 O
t Multiply by 9.35 xlO to convert to m /ha/day
I Multiply by 0.89 to convert to kg/ha/day
** RI - Rapid Infiltration
111
-------
Some characteristics of the application systems are pre-
sented in Table 17.
Industrial Sludges
Loading rates of industrial sludge depend on the waste
composition, site characteristics, and crops to be grown, if
cropping is planned. Except for oil refinery sludges, data on
application rates for industrial sludges are meager.
Waste composition and percent solids generally dictate
the amount of sludge to be applied at the land cultivation
site. The waste loading rate can be determined according to the
partial requirement of crops for nitrogen and/or phosphorus
such as for paper mill and fruit cannery sludges. High con-
centrations of such constituents as sodium (food processing
waste), sol uble salts and zinc (pharmaceutical waste), and
nonessential metals (tannery and refractory metal processing
waste) may limit the quantity of sludge which can be safely
disposed of on land with regard to crop production and/or soil
accumulation.
Although the USDA has suggested heavy metal loading
guidelines for agricultural disposal of municipal sewage sludge,
no loadings for these heavy metals or other persistent, toxic
constituents are recommended for nonagricultural soils. Most
disposal site operators are aware of the potential hazards of
heavy metals and other toxic constituents entering the food
chain when a hazardous waste is land cultivated. However, the
question arises as to the loading of various waste constituents
if the land cultivation site is intended for disposal only.
Only two states (Texas and Oklahoma) have regulations or
guidelines on land cultivation with respect to heavy metal
loading (see Section 8). It is reasonable to assume that under
proper site management, if the heavy metals or other hazardous
waste constituents are shown by soil analysis to remain in the
plow layer (equivalent to surface 60 cm), there should be
no limit on the quantity of waste that can be applied at the
land cultivation site.
Research work has recently indicated that fruit cannery
sludge (103) can be applied to fine-textured soil up to 250
t/ha (dry wt) and refractory metal processing waste (79) up
to 112 t/ha without resulting in groundwater contamination
or reduced crop yield. Frequency of applications and long-term
environmental effects resulting from land cultivating these
sludges have not been reported. Generally, if large acreage of
land is available for sludge disposal, such as the operation in
Gilroy, California, for cannery waste, the land will receive
only one application (617 m^/ha) per year (Felice, personal
communication).
112
-------
TABLE 17. COMPARATIVE CHARACTERISTICS OF LOW-RATE
IRRIGATION OVERLAND FLOW, AND
INFILTRATION-PERCOLATION SYSTEMS*
Factor
Liquid loading rate
Annual application
Land needed per 1 mg
Soils
Slopes
Removal of suspended
solids and BOO
Removal of nitrogen
Removal of
phosphorus
Fate of wastewater
Design Approach
Low-rate Overland
Irrigation Flow
0.5 to 4 in/ 2 to 5.5 in/wk
wkt
2-8 ft/yr 8 to 24 ft/yr
140 to 560 ac 46 to 140 ac
plus buffer plus buffer
zones zones
Moderately per- Slowly per-
meable loamy meable silt
sands to clay loams to clays
loams
Cultivated 2-6%
crops: 0-6%.
Forages and
forest species:
0-15%
90 to 99% 90 to 99%
80 to 100% 70 to 90%
(may exceed
100%)
95 to 100% 50 to 60%
(may exceed
100%)
Evapotranspir- Runoff maxi-
ation and deep mi zed for re-
percolation covery and re-
for groundwater use* Rela-
recharge, dis- tively little
charge into evapotranspir-
surface waters, ation or deep
or recovery percolation.
and reuse. Run-
off controlled.
Infiltration-
Percolation
4 to 120 in/wk
18 to 500 ft/yr
2 to 62 ac
plus buffer
zones
Rapidly per-
meable sandy
loams to sands
Less than 2%
90 to 99%
0 to 80%
70 to 95%
Deep percolation
maximized for
groundwater
recharge, re-
covery and re-
use. Runoff con-
trolled. Negli-
gible evapotrans-
piration.
* Adapted from Thomas and Harlin, Jr. (m) and Pound and
Crites (23).
t Irrigation at 4 in/wk would be seasonal. An 8 ft/yr application
would average 2-1/2 in/wk over a 40-week irrigation period.
113
-------
In the land cultivation of oil refinery sludges, the
waste is usually spread to a layer between 7.6 and 15.2 cm
thick. Lewis (28) reported sludge at an average of 1,008
t/ha/yr (450 tons/ac/yr) was applied at one refinery. This
amounts to 112 t/ha/mo (50 tons/ac/mo) based on a 9-mo opera-
tion. Generally, when the oil content in the surface 15 cm
(6 in) decreases to 2 to 4 percent, additional sludge can be
applied. Under normal operating conditions this would take
about 2 mo. Waste application on such a frequency precludes
growth of any cover vegetation. According to the experience
of the researchers at an Oklahoma refinery, the optimum
application rate for refinery wastes appears to be at 5 per-
cent oil in soil (Huddleston, personal communication). This
is equivalent to 112 t oil/ha (50 tons/ac), based on surface
15 cm (6 in) of soi1 .
SOIL AMENDMENTS
In addition to climatic factors, it is important to
provide an optimum soil environment for microbial decomposition
of waste material. Nutrient and moisture requirements, liming,
and microbial seeding are discussed.
Nutrients
Most of the waste applied to soil can serve as an energy
source and provide some essential elements for the growth of
soil microorganisms. Since most nutrients (except probably
for nitrogen) are abundant in soils, they are not a limiting
factor in normal degradation processes.
When a highly carbonaceous material such as municipal
solid waste or an oily sludge is added to a soil, the C/N
ratio of the surface soil is increased substantially. To
maintain a, favorable C/N ratio (10 to 20:1) and reasonable
degradation rate, addition of nitrogen fertilizer during soil
incorporation is necessary, particularly if vegetation is
included in the waste management program.
Additions of nitrogen and phosphorus fertilizers were
found to greatly enhance microbial decomposition of oils
(27, 112). At one refinery, maintaining available nitrogen
and phosphorus concentrations at 20 to 30 ppm is recommended
(28). This recommendation is arbitrary. A fertilizer program
should be made based on the evaluation of waste composition
and soil fertility. It is important to determine the C/N ratio
of the waste to be land cultivated as well as the fertility
status of the soil. If the C/N of the waste is large and the
soil fertility is low (e.g., marginal land), calculations can
be made as to the quantities of fertilizer nitrogen (and/or
phosphorus, calcium) that are needed to increase microbial
114
-------
degradation of the waste added without causing groundwater
pollution due to leaching of the fertilizer added.
Moisture
Water is a universal transport medium for all biological
processes. Maintaining soil moisture at field capacity would
be ideal for microbial decomposition of wastes. Waterlogging
is undesirable since it creates anaerobic and nuisance con-
ditions .
In field operations, it has been suggested that water
be applied to municipal solid waste through sprinklers to con-
trol blowing of debris and to reduce waste volume (79). Waste
decomposition ratesmay decrease considerably under arid con-
ditions. Additional water is seldom applied to the soil which
receives industrial wastewater or sludge. In practice, high
evaporative loss is preferred to enable increased frequency
of sludge application.
pH Adjustment
Unless the waste is used as a soil amendment to adjust pH
(e.g., application of concentrated sulfuric acid to sodic
and strongly alkaline soils, or using fly ash as a liming
material on strongly acidic soils), the pH of the waste is
not extreme. Thus, the change in soil pH due to waste appli-
cations is a slow and reversible process.
Maintaining a soil pH near 7 is important since it is
favorable for microbial activity and plant growth. However,
the purpose of maintaining soil reaction near pH 7 at some land
cultivation sites is primarily to retain phosphorus and heavy
metals in the surface soil. In land treatment of wastewater,
adjusting the soil to neutral is not a common practice.
Microbial Seeding
Since most soils have a large and diverse population of
microorganisms, it is generally assumed that if optimum con-
ditions are maintained, biodegradation of the added waste will
proceed at a reasonably rapid rate.
SOIL INCORPORATION PROCESSES
Since land cultivation is designed to be an aerobic
decomposition process, it is important to keep the soil-waste
mixture aerated by frequent mixing. In practice, however,
disking or rototilling operations vary with waste type and
location.
115
-------
At most land cultivation sites, soon after the waste
is spread and leveled over the area, it is mixed with the
soil by disking or rototilling. However, if wastewater or
dilute liquid sludge is applied to a soil, especially when a
cover vegetation is present, no disking is involved. Sub-
surface injection of industrial sludge would result in partial
mixing of'the waste with soil, and generally disking is not
required.
The practice of land cultivation of shredded municipal
refuse in Odessa has indicated that a second mixing 3 to 6 mo
following waste application is beneficial since high winds have
resulted in wind erosion thereby exposing the refuse initially
mixed with soil. In addition, the second mixing may enhance
the degradation process.
For most industrial sludges, the waste is spread or
leveled to a thin layer immediately following application and
allowed to dry for a few days. After initial drying, the
material is incorporated into the soil by one to several disk-
ings. Depending upon the visual appearance of the decomposi-
tion products and the general weather conditions, additional
disking and drying periods are completed as necessary. This
procedure has been adopted for cannery wastes in Gilroy,
Cali fornia.
At most land cultivation sites receiving oily sludges,
initial drying generally takes from 1 to 3 wk depending on
waste loading and evaporation. The waste is then mixed into
the soil by a track dozer and/or disking. Subsequent mixing
is done at weekly to monthly intervals. The soil is sometimes
disked and leveled as part of site preparation prior to
receiving additional waste.
MANAGEMENT CONSIDERATIONS
In the land application of wastes, it is generally agreed
that if the site is properly managed, many adverse effects
resulting from waste disposal or utilization can be mitigated.
Management of a land cultivation site consists of:
0 Soil management
Timing of operation
Other management considerations, such as control of
wind movement and snow distribution, and site
monitoring.
116
-------
Soil Management
The goals of soil management are to immobilize heavy
metals and other toxic constituents, increase the decomposi-
tion of waste materials, control soil erosion and runoff, and
prevent groundwater contamination.
Immobilizing Heavy Metals and Other Toxic Constituents--
Various studies have been performed on heavy metal move-
ment in landfills or in soils with incorporated sewage sludge.
The studies show that most heavy metals are less mobile under
neutral-to-alkaline and well-aerated conditions.
Increasing the Decomposition of Waste Materials--
Organic waste decomposition depends on waste type and
loading rate, as well as on aeration, nutrients (e.g.,
nitrogen and calcium), water content, and air temperature
(see Section 5). Repeated heavy waste application may lead
to anaerobiosis, which slows down waste decomposition, and to
deterioration of soil structure. It is important to maintain
a neutral soil reaction and good aeration, since these con-
ditions are favorable for the microbial degradation of the
added organic wastes.
Controlling Soil Erosion and Runoff--
Soil erosion is a function of rainfall, soil properties,
slope length and steepness, cropping sequence, and supporting
practices (113). Methods of minimizing soil erosion would
likewise control on-site runoff and pollutant transport.
Although nothing can be done to change the amount, distri-
bution, and intensity of natural rainfall, there are meas.ures
to reduce its erosiveness, i.e., to decrease impact raindrop
and splash energy, as well as the amount and velocity of over-
land flow (114). For wastewater application by sprinklers or
other means, methods should be chosen and managed that result
in a low impact and splash energy.
Slope length and steepness affect pollutant transport,
which can be modified by supporting practices (e.g., terraces,
diversions, and drains) and cropping. Terraces restrict slope
length and provide orderly disposal of runoff (115), and can
be designed to meet specific needs. For example, broad-basis
terraces are used to control runoff and to collect transported
solids (116); level bench terraces are used to impound
potential runoff in a large area and to allow for infiltration
(117, 118). Overland flows that originate off-site create
the same problems as on-site runoff. Diversions can be
117
-------
utilized to protect an area or a structure from runoff (119),
to divert water out of active gullies, or to shorten the length
of slope for erosion control. A diversion must have an
adequate outlet and be designed for safe flow velocities ex-
pected in bare channels. Runoff and/or overland flow can
also be controlled by maintaining adequate drainage. Excess
water may be removed from the site by open or covered drains
(120). Methods for maintaining subsurface drains have been
described by the Soil Conservation Service (121). Ham (118)
discussed the use of drainage wells for control of water tables.
Vegetative cover and surface mulch are other effective
means of controlling runoff and erosion (122, 123). Vege-
tative cover protects against raindrop impact, reduces detach-
ment, and lessens surface scaling, all of which lead to high
water intake. Mulch creates barriers and obstructions, which
reduce flow velocity and carrying capacity, reducing transport.
Relatively modest reductions in flow velocity result in large
reductions in erosion rates, since the quantity of material
moved is proportional to about the fourth power of velocity
(123).
Preventing Groundwater Contamination--
Groundwater contamination can be reduced by practices
that promote microbial degradation of wastes, enhance heavy
metal retention in the surface soil, and remove nutrients
and potentially hazardous waste constituents by plants. In
addition, contamination can be reduced by avoiding the over-
loading of waste on the land cultivation site (124).
Timing of Operation
The timing of operations must take wind, precipitation,
and air temperature into account. For instance, when the
direction of the wind can cause odor problems, operations
should be suspended. Also, winds are often calmest in early
morning, late evening, and through the night. Thus, applica-
tions of odorous wastes should proceed at these times, avoiding
winds that cause waste to spread beyond the site boundaries.
In addition, precipitation can influence operations, particu-
larly in humid climates, since applications onto rain-soaked
soil contribute to runoff and should therefore be avoided.
Other seasonal weather factors must also be considered, such
as freezing and resultant loss of microbial efficiency due
to cold weather. Waste storage is required when freezing
temperatures do not permit winter operation, or where
regulations prohibit application on snow-covered ground. If
the site is used for crop cultivation, schedules for water-
application must be adjusted according to rainfall to avoid
over-irrigation. Hence, management personnel must have a
118
-------
working knowledge of farming practices as well as orinciolps
of waste disposal. K
Other Management Considerations
Other management considerations include the control of
wind movement, snow distribution, and site monitoring.
Control of Wind Movement and Snow Distribution--
Proper landscaping of a site reduces wind movement and,
where applicable, controls snow distribution. Woodruff et al.
(125) reported that a field windbreak can moderate summer
wind movement. This is desirable because strong winds can
move waste materials before they can be incorporated into the
soil. Such windblown materials will accumulate in depressions
and erosion rills; they will thus be subject to overland move-
ment and leaching with succeeding rain and irrigation water.
The design of natural, live windbreaks, and recommendations for
species and their management can be obtained from the Soil
Conservation Service. Live windbreaks of shrubs and trees can
promote the removal of soil moisture from the disposal area
by evapotranspiration. Manmade barriers can serve in the
early development of a disposal area until natural, live wind-
breaks are established and effective.
Manmade barriers, such as snow fences, are effective for
influencing snow distribution (126, 217, 128). These barriers
must be properly placed to avoid unwanted drifts and excessive
volumes of meltwater that are concentrated in certain parts
of the disposal area. Wei 1-distributed snowmelt minimizes
transport of waste materials and eroded soil caused by overland
flow.
Site Monitoring--
Any land cultivation operation must have an ongoing mon-
itoring schedule that includes observing system performance,
monitoring the quality of affected natural systems (e.g.,
underlying groundwater), and evaluating environmental impacts
with quality changes. Details of site monitoring are dis-
cussed in Section 12.
There are no overall formulas to guide a monitoring pro-
gram, since each waste and Us method of disposal is unique.
Monitoring should begin with assessing the chemical composi-
tion of the waste. Such information confirms, on a day-to-day
basis, that the waste is acceptable for cultivation and provides
a record of land loading. Monitoring should also assess soil
and groundwater quality.
119
-------
If crops are harvested for human or animal consumption, the
extent of folian contamination and plant uptake of waste con-
stituents must be determined. The health and welfare of
workers within the site must be carefully observed if there is
body contact with the material or inhalation of aerosols.
Public health protection may demand adequate disinfection
before application of certain wastes.
120
-------
SECTION 11
ENVIRONMENTAL IMPACT ASSESSMENT
Soil, a natural acceptor of wastes, has been viewed as a
physical, chemical, and biological filter that can effectively
deactivate, decompose, or assimilate a wide range of waste
materials. Factors affecting this assimilative capacity must be
understood and considered to develop sound management systems in
land cultivation.
Published information on the environmental impacts of land
cultivation of municipal solid wastes and industrial wastewaters
and sludges is not sufficiently well understood to make precise
predictions of impacts. For this reason, studies dealing with
the disposal of these wastes at landfills or of land-farmed sewage
sludges have been used and the knowledge extrapolated to land
cultivation conditions where appropriate.
SOIL-WASTE INTERACTIONS
It is highly desirable to predict the behavior of the
proposed waste within the soil system at the outset of a land
cultivation practice to predetermine the impact of the practice
on the receiving environment. To predict the consequences of
land disposal of any waste material, the various chemical,
physical, and microbiological processes that describe the move-
ment and fate of constituents in the soil-water environment must
be understood. For precise predictions, knowledge of the local
hydrogeologic environment integrated with characteristics of
various waste types is also necessary.
A major difficulty in predicting soil-waste interactions is
the inherent variability of the waste. To predict the inter-
actions which occur between a waste product and the soil, the
chemical -and physical properties of the waste must be adequately
characterized. In particular, the range or variability of the
composition of the waste should be known.
When a waste is applied to soil it triggers a series of
soil-waste interactions that determine the fate of various
constituents present in the waste. Some of the more important
interactions, which are extremely complex, are adsorption, ion
exchange, complexation, precipitation, oxidation-reduction, and
enzymatic degradation (47, 51, 129, 130).
121
-------
Mathematical models which describe soil-waste interactions,
including adsorption, storage, and consumption of chemicals in
soils, have been developed and summarized (47). The basic
approach is to consider generalized flow models and then integrate
various component models into the general model for the prediction
of movement and attenuation of contaminants through soils.
Organic Wastes
Addition of organic wastes to soil usually results in
increased microbial activity. Carbon dioxide, water, and micro-
bial cells are the main products of aerobic metabolism. The
proteins, carbohydrates, nucleic and fatty acids, amino sugars,
and other organic materials found within microbial cells will be
readily degraded by the common biochemical pathways of glycolysis
such as the tricarboxylic acid cycle, and B-oxidation (46, 51, 131).
The refractory organics in wastewaters and sludges (estimated
by the difference between the values of COD and BOD) are slowly
degradable. These include phenols, detergents, fats and waxes,
hydrocarbons, cellulose, lignin, tannin, plant and bile pigments,
pesticides, and humic compounds (51). The duration which these
substances remain in soils depends on their concentration and on
the soil environment. With physical entrapment and chemical
sorption of these compounds in the soil matrix, effective micro-
bial degradation should occur.
One important aspect of soil-waste interactions is the
microbial methylation of trace elements. Rogers (132) reported
that methylation of mercury in agricultural soils was directly
proportional to clay content, moisture content, soil temperature,
and mercury concentration. Methylation of inorganic and organic
forms of many elements is a common microbiological metabolism
which results in their mobilization through volatilization and
increased toxicity (Table 18). The methylated forms of lead,
TABLE 18. MICROBIAL FORMATION OF METHYLATED COMPOUNDS*
Element Methylated Product1"
Hydrogen CH4+
Lead
Mercury (CH3)2Hg+, CH3Hg+
Arsenic (CH3)2AsH-t-, (CH3)3.As-t-
CH3AsO(OH)2, (CH3)2AsO(OH)
Sulfur (CH3)2S+, CH3SH, (OH3)2S2
Selenium (CH3)2Set, CH3SeH, (CH3)2Se2
Tellurium (CH3)2Te+
*Surnmarized by Doran et al . (135).
tt = volatile compounds
122
-------
mercury, arsenic, and tellurium are more toxic than their inor-
ganic precursors, and the occasional magnification of these
substances in the food chain (primarily fish) creates a pollution
problem requiring perennial vigilance (133). The potential
health hazards associated with volatilization of methylated heavy
metal at a land disposal site has not been reported in the
literature.
Inorganic Wastes
Soils comprise a dynamic system in which numerous chemical
reactions occur simultaneously. Equilibrium, in its true sense,
is probably never attained in soils. When an inorganic waste is
added to a soil, it may interact with the soil solids, liquids,
and gases (Figure 24) (134); after the waste is incorporated
into the soil, the soluble constituents enter the soil solution
(reaction 1). The released cations can exchange with those
already on exchange sites in the soil (reactions 2 and 3). .When
the activities (effective concentrations) of ions in solution
exceed the solubility products of solid phase compounds and
minerals, these compounds can precipitate (reaction 4). When
the soil solution is under-saturated with respect to solid
phases or minerals present, these solid phases can dissolve
(reaction 5). Ions in the soil solution can be removed by
plants or leached from the soil (reaction 6). Waste consti-
tuents are also assimilated by microorganisms and incorporated
into soil organic matter (reactions 7 and 8). Gaseous consti-
tuents enter the soil air and may escape from the soil (reaction
10), or components of the soil air may react with the soil
solution and become part of the soil matrix (reaction 9).
Exchangeable Ions
and Surface Adsorption
Organic Matter and
Microorganisms
Solid Phases
and Minerals
Removed by
Plants and Leaching
Figure 24. Reaction of wastes with soils (134).
123
-------
The soil solution is affected by all the reactions that
occur as constituents are added or deleted. The composition of
the soil solution is ultimately controlled by the solubility of
various mineral and organic phases in the soil, and the environ-
mental factors of moisture, temperature, and aeration. In many
reactions, the rates of precipitation and dissolution are suffi-
ciently slow that kinetics, as well as thermodynamic factors,
must be considered.
WATER QUALITY
Land cultivation must adequately protect the surface and
subsurface waters from contamination with the potentially toxic
constituents present in the waste or regulting from waste
decomposition. Wastewater constituents that are not used by
plants, degraded by microorganisms, or fixed in the soil may
leach to the groundwater. Runoff resulting from excess waste
application or heavy rains may carry the constituents and sedi-
ments to nearby streams and lakes.
Migration to Groundwater
Incorporation of wastes into the surface soil may result in
soluble contaminants moving downward by infiltration and leach-
ing, or percolation. Many factors are involved in determining
whether the contaminants are reduced to harmless proportions
before they reach the groundwater. These factors include
hydraulic conductivity, soil structure, soil texture, evapotrans-
piration, rainfall intensity and duration, and soil sorption
properties (47). The degree of attenuation and loss in potency
or concentration of the contaminated water at a distance from
the waste sites must also be considered.
The major mechanisms causing movement of chemicals in the
soil are molecular diffusion in, and convection with, water as
the water moves through the soil. The ion transport through
the soil profile is controlled by a number of factors: 1) pore
size continuity, 2) fluid dispersion, 3) cation and anion
exchange capacity, 4) cation and anion exchange equilibrium,
5) rate of cation and anion exchange, and 6) soil water content
(136). These factors are discussed later under Soil Attenuation.
2-
Because anions such as HC03, $04 , Cl , N03 are soluble in
water and most soils have limited anion exchange capacity, they
will be the most likely to appear in the groundwater. Crop
removal of potential pollutants (e.g., nitrate and orthophosphate)
can play a significant role in reducing pollution hazards to
the groundwater (137).
Based on information on the chemical composition and appli-
cation rates reported in laboratory and field studies, incorpora-
tion of municipal solid wastes into the surface soil at
124
-------
agriculturally possible rates probably would not contaminant
groundwater supplies with heavy metals, toxic chemicals, or
pathogens. If groundwater rose such that it came in contact with
the applied waste, the possibilities of groundwater contamination
would rise considerably. This suggests that land cultivation of
wastes in shallow groundwater areas would not be allowed.
In a study on the movement of elemental constituents in
a Sagehill loamy sand (pH 7.5) treated with shredded municipal
refuse, nitrate was the only ion studied which posed a threat to
groundwater quality problems (14). This nitrate was from the
nitrogen fertilizer which had been added to the soil to help
alleviate the high C/N ratio of the carbonaceous refuse. Boron
and total dissolved salts may be present at elevated concentra-
tions in the groundwater if soils have high percolation rates
and the municipal solid wastes are added in a long-term program.
The potential for groundwater contamination with industrial
wastewaters and sludges is greater because the wastes are in
liquid form and because the contaminants are present at greater
concentrations in comparison to municipal solid wastes. Instances
have been recorded of groundwater contamination by industrial
wastes containing hazardous constituents (heavy metals, toxic
organics, radioactive materials, cyanide, etc.) (138). These
instances appear to be the result of wastewater impoundments and
improper burial or open dumping of solid wastes.
Considering the extent of land cultivation practices and
the types of industrial wastewaters and sludges suitable for
soil incorporation, the constituents that would most commonly
pose a pollution potential to the groundwater would be nitrate,
salinity, and possibly BOD (resulting from hydraulic or organic
overloading of the wastewaters and sludges). Certain wastes that
contain high concentrations of various elements could contaminate
waters with these elements. For example, from a laboratory
experiment, Poison (79) suggested that fluoride may present a
problem to groundwater when a refractory metal processing waste
was applied at a rate of 2 percent or more to a Dayton silty
clay loam. However, when the same waste was applied in the field
at rates of up to 224 t/ha (100 tons/ac), no increase in fluoride
content in the soil profile was observed.
Adriano et al. (137) presented data on the effect of long-
term land disposal by spray irrigation of food processing wastes
on the nitrate and phosphate levels of the subsurface waters.
The two study sites had coarse-textured soils and shallow sub-
surface waters. During seasons of major irrigation, nitrate
appeared in subsurface waters in concentrations exceeding public
health standards; phosphate concentrations exceeded environ-
mental guidelines at all times. Annual additions to subsurface
waters were estimated at 76 and 65 percent of input nitrogen,
respectively? at ?he two study sites. The corresponding figures
125
-------
for phosphate were 27 and 2 percent. Data presented suggests
that the rates of accumulation of excess nitrogen and phosphorus
in the soil profile could have been reduced materially if vegeta-
tion at these sites had been cut periodically and harvested. How-
ever, in the case of nitrogen, it appears that long-term protection
of groundwater supplies through nutrient cycling in land disposal
systems cannot be achieved if levels of input nitrogen are much
greater than the quantities which can be removed in harvested crops.
Carbaryl, a nonpersistent insecticide, was applied at
25.4 kg/ha to a Congaree sandy loam field plot containing a
shallow (about 1.1-m) water table (139). Within 2 mo after
soil application, carbaryl appeared in the underlying groundwater
where it persisted at least 8 mo. Maximum groundwater
concentration (at the end of the second month) was about 0.3
mole/1. This concentration may be safe for animal consumption.
Considerable information is becoming available on the move-
ment of trace elements and toxic chemicals in soils under
laboratory conditions. However, there is only limited field data
available on the contamination of groundwater by metals and toxic
chemicals in the industrial wastewaters and sludges that are
disposed of by land cultivation. The potential for groundwater
pollution always exists, and waste overloading occurs, particu-
larly when irrigation or rainfall is heavy and under extreme
soil conditions such as prolonged water-logging, low pH (<5),
and in sandy soils with a shallow water table.
Soil Attenuation
Consideration of the role of soils for management and
utilization of wastes must take into account the chemical reac-
tions that may occur with the waste constituents. The reactions
can be grouped conveniently into: 1) ion exchange, 2) adsorption
and precipitation, and 3) complexation. The mechanisms and
rates of most, if not all, of these reactions are dependent upon
the type and amounts of clay, hydrous oxide, and organic matter,
as well as upon more dynamic properties, including solute compo-
sition and concentration, exchangeable cations, pH, and oxidation-
reduction status.
Ion Exchange
The ion exchange capacity of soils varies primarily with:
Kind of clay mineral present
Quantity of clay mineral and/or
amorphous materials
t Amount of organic matter present
pH of the soil.
126
-------
The dominant exchangeable cations are Ca2+ Mg2+ K+ Na+ A13+
and H+. Under waterlogged conditions, Mn2+ and Fe2+'may occupy'
a significant portion of the exchange complex. Because of their
low solubility and low concentration in the soil solution, heavy
metals such as Pb^+ and Cd2+ are not competitive with common
divalent cations (such as Ca2+) for clay adsorption sites (140)
The precipitation of heavy metals, as well as iron and aluminum",
may block exchange sites. Although the cation exchange capacity
of a soil is considered in the application rate of sewage sludges
(or heavy metal loading) to agricultural soils, it serves more
as an indicator of overall soil properties rather than being the
specific mechanism by which heavy metals are fixed in soils.
The extent of metal participation in true exchange reactions
varies, depending on the metal, metal concentrations, soil
constituents and their corresponding properties, pH, and presence
of chelating agents (130).
While cation exchange is the dominant exchange process
occurring in soils, some soils do retain anions such as NOs and
SO?" on exchange sites. Anion exchange is especially important
in acid-weathered soils high in hydrous oxides and kaolinite.
Singh and Kanehiro (141) reported that two Hawaiian soils sorbed
from 1.3 to 2.6 meq N03/100g soil at pH 5.0, with the amount
decreasing as pH increased. It is unlikely, however, that this
type of sorption would be significant, except in areas where
soils are acid and contain considerable amounts of amorphous
materials, hydrous oxides, and kaolinite.
Sorption and Precipitation Reactions--
These two reactions are often in competition, with precipi-
tation dominating at relatively high concentrations of reactants.
Several types of mechanisms have been postulated for the process
of removing an ion from solution and bonding it to a solid
surface, including physical sorption, chemisorption, and
penetration into the solid mineral phase (130).
Retention of phosphate, arsenic, sulfur, selenium, molybde-
nium, boron, and trace metals has been discussed (129, 130, 142).
Several mechanisms for the retention of metals in soils have been
proposed. Hodgson (143) listed these reactions as: 1) associa-
tion with soil surfaces, 2) precipitates, 3) occluded in other
precipitates, 4) native constituents of soil minerals, 5) solid-
state diffusion into soil minerals, 6) incorporation into
biological systems or residues. While all of these reactions
undoubtedly operate to some extent in surface soils, differences
in the relative importance and rates of these mechanisms exist,
depending on the metal, soil properties, and environmental
conditions.
The factors controlling the relative dominance of precipi-
tation over surface sorption in the retention reactions of metals
127
-------
are solution metal concentration, pH, ion pair formation, and
possibly existence of organo-metal complexes (144, 145, 146).
High concentrations of metals favor precipitation, forming oxides,
hydroxides, and other solid phases (carbonates, sulfides, etc.)
of low solubility, particularly at higher pH values (124). This
concept is simplified by the following equation:
Zn2+ + 2 OH" > Zn(OH)2(s)
Precipitation occurs when [Zn2+] [OH"] exceeds the solubility
product (Ksp). Conversely, when [Zn2+] [OH"]^ drops below the
KS , the solid phase Zn(OHJ2 begins to dissolve.
It is commonly found that with the exception of selenium,
arsenic, molybdenum, and some valency states of chromium, the
availability of metals decreases or sorption increases with an
increase in soil pH (16, 129).
Organic matter is often regarded as a major factor in the
sorption of metals. Humic and fulvic acids have relatively high
stability constants for metals (146). The organic link to the
trace metals, however, is limited not only by its chemical
stability, but by its susceptibility to microbial attack, which
can release the element for chemical reaction with soil constit-
uents and/or further microbial incorporation (46).
Considerable evidence has accumulated indicating that hydrous
metal oxides play a major role in the attenuation of heavy
metals in mineral soils (142). These oxides, particularly those
of iron, manganese, and aluminum are common in soils. They have
high surface areas in relation to their weight, are highly
reactive, and are of indefinite structure and composition.
Reducing conditions in soil have been reported to promote
mobility of some trace metals (Cr, Ni, Cu, Zn, and Co), and
noticeably of Fe and Mn (147). This would suggest that where
drainage is poor in soils, these metals become more soluble and
mobile through soil. However, it is generally true that the
sulfide system controls the mobility of trace metals under
anaerobic conditions (147, 148). Sulfide (formed under highly
reduced conditions) reacts with trace metals to form very slightly
soluble precipitates. Attenuation of trace metals in reduced
soil conditions, thus, depends on a number of chemical and micro-
biological transformations.
Complexation--
Waste streams may contain many organic substances which can
react with trace metals. Classes of organic compounds which have
the greatest potential for serving as electron donors in metal
complexes include enolates, alkoxides, carboxylates, phenoxides,
alkyl amino, heterocyclic nitrogen compounds, mercaptides,
phosphates, and phosphonates (149). Stabilities of complexes are
128
-------
normally measured by the equilibrium constants for complex
formation and expressed by stability constants. In soils the
metal-organo complexes may be degraded biologically, releasing
the trace metals at varying rates (46).
High molecular-weight humic substances (e.g., humates and
fulvates) containing condensed aromatic nuclei in complex polymers
have a high affinity for metals. This complexation contributes
to the retention of trace metals in soil (146).
Low molecular-weight biochemicals of recent origin (e.g.,
organic acids and bases) demonstrate relatively high solubility
in association with metals. These substances, while present
only in small quantities in soil, are present in sufficient
quantities in water-soluble forms to play a significant role in
solubi1ization of trace metals in soil.
Physical Properties Attributable to Soil Attenuation--
In addition to the chemical properties discussed previously,
some physical properties of soil also directly or indirectly
affect the attenuation mechanisms. Among these physical proper-
ties are soil texture (or particle size distribution) and pore
size distribution.
Many attenuation mechanisms involve physical and chemical
reactions on surfaces. The greater the surface area available,
the greater is the potential for attenuation of these mechanisms.
Because of greater surface area per unit weight, finer soil
materials (silt, clay, and colloids) have greater attenuating
characteristics than coarser soil materials. In general, the
finer the soil texture, the less the migration of trace metals.
Colloidal hydrous oxides and oxides of Fe, Mn, and Al react
strongly with most of the trace*metals and are reported to retain
them against exchange much more tenaciously than do the clay
minerals (142, 143). Also, these hydrous oxides coat particles
such that a small amount of the oxides can have a profound
effect on attenuation.
Because soluble constituents move through water in soil
pore spaces and because soil water travels more rapidly through
larger than through smaller pore spaces, the pore size distri-
bution of a soil has a profound influence on migration of trace
metals. Fine-textured soils with small diameter pores will
restrict the migration of trace metals by slowing the rate of
water movement through the soil, which in turn, allows more time
for the metals to react physically or chemically with the soil
particles.
Soil aeration and drainage, which are closely related to
soil texture and pore size distribution, affect attenutaiton
mainly through oxidation-reduction (redox) reactions. The
129
-------
changes in redox potentials following flooding and their
relationships with the availability or mobility of nutrients and
metals have been reviewed (147, 148). Under aerobic conditions,
the solubility of most metals is low, and their toxicity and
mobility are correspondingly reduced.
Published Information on Soil Attenuation--
Based on information in the literature, Fuller (129) grouped
qualitatively 12 constituents studied with respect to mobility
in soil under aerobic conditions:
Relatively mobile - cyanide (CN~), selenium
(HSeO^ and SeO~~), and Cr(VI). The mobility is
similar to almost uninhibited movement of Cl~,
moving at the same rate as soil solution.
t Moderately mobile - iron, zinc, lead, copper,
and beryllium. The mobility is between
"relatively mobile" and "slowly mobile."
Slowly mobile - arsenic (f^AsO^.), cadmium,
chromium (III), mercury, and asbestos (<2 y). The
mobility is between "slowly mobile" and "immobile.
Immobile - asbestos (>2 p). The mobility is
similar to the rate of movement of clay-sized
particles in soil.
The mobility classes defined by Fuller (129) are arbitrary
generalizations from the 250 references cited in his report.
While it is somewhat misleading to generalize about the mobility
of ions without specifying the conditions, the generalization has
some value in identifying ions requiring greater care upon
disposal.
In a laboratory study, Fuller and Korte (150) evaluated
the attenuation of 11 trace metals by leaching acidified land-
fill leachate (pH 5, spiked with 70 to 120 ppm of the element
of interest) through 11 soil types under anaerobic conditions.
They cited the important factors in attenuation as clay and
free iron oxide content, soil pH, and solution flux through soil.
Trace metals were placed into three categories, according to
relative mobility under anaerobic conditions: 1) most generally
mobile - chromium, mercury, and nickel; 2) least generally
mobile - lead and copper; and 3) mobility varies with conditions -
arsenic, beryllium, cadmium, selenium, vanadium, and zinc.
Although the criteria used to group these elements into three
mobility classes are not given, the groupings may be generally
inferred from the data, given in the paper, on time to first
appearance of an element in the soil column effluent.
130
-------
v r irl\ *" iller (144) rePorted that cyanide - as KCN and
K3Fe(CN)6 - in water was very mobile in soils, while KCN in land-
fill leachate was complexed and less mobile. Soil properties
such as low pH, the presence of free iron oxide, kaolin, chlorite
and gibbsite-type clay tended to increase attenuation of cyanide.
High pH, the presence of free CaCO., and montmorillonite-type
clay tended to increase the mobility of these cyanide forms.
The effect of pH on removal of heavy metal is demonstrated
by the work of Griffin and Shimp (145). These data show that
adsorption by clays of cationic heavy metals - lead, cadmium,
zinc, copper, and chromium (III) increased with increasing pH,
while adsorption of anionic species - chromium (VI), arsenic,
and selenium decreased as the pH increased. In another study
(151), leachates collected from a sanitary landfill were run
through columns of clay, and effluents were periodically collected
and analyzed for 16 chemical constituents. The results show that
chloride, sodium, and water-soluble organic compounds (COD) were
relatively unattenuated by passage through the columns; potassium,
ammonium, magnesium, silicon, and iron were moderately attenuated;
and lead, cadmium, mercury, and zinc were strongly attenuated.
Concentrations of calcium, boron, and manganese were markedly
higher in the effluents than in the original leachate. Of the
three clays tested in this, study, montmorillonite had the highest
attenuation capacity, followed by illite and then kaolinite.
Field observations (16) have indicated some movement of
trace elements irv soil following sewage sludge applications over
long periods (decades). In most instances, however, except for
boron, the movement into lower soil depth (below 3m (10 ft)) of
trace elements applied in the waste was restricted. Even though
all toxic metals are largely fixed in the surface layers of soil,
rather small increases in trace element solubility combined with
subsequent movement to the water table could result in deteri-
oration of groundwater supplies.
An investigation was conducted of possible contamination of
groundwater with lead and zinc in the "new lead belt" mining
region of southeast Missouri. Jennett and Linnemann (152)
leached two soils collected in the area with solutions of lead
and zinc acetate and fluoroborate containing 100 and 250 ppm
zinc or lead. Although no data on zinc and lead concentrations
in the leachate were shown, they concluded from the study that
heavy-metal contaminated soils in this region did not contribute
to heavy metal contamination of the groundwater supplies. How-
ever, based on the acidic nature of the soils (pH 5.2 and 5.6)
and leaching solutions (pH 3) and the quantity of solution
(equivalent of 20 yr of annual rainfall) percolated through
the soil, more work is needed to substantiate this conclusion.
131
-------
The attenuation and persistence of pesticides in soils
depend on the chemical formulation and water solubility of the
compounds and their absorbtivity in soil colloids. Mobility
of some selected pesticides of Hagerstown silty clay loam is
presented in Table 19 (153).
Filonow et al. (154) found insignificant movement of
2,2',4,4',5,5'-hexabromobiphenyl (HBB), a mixture of polybromi-
nated biphenyls (PBB's), through four Michigan soils amended with
100 ppm HBB (soil basis). Only traces (2-3 ppb) of HBB were
detected in the leachates even after collecting 1,592 cm (769 in)
of leachate. The results suggest that PBB's, which are present
in some Michigan farm soils due to applications of PBB-contami-
nated manure, should not leach below the depth of incorporation.
Burnside et al. (155) studied, under field conditions in
Nebraska, the dissipation and leaching of monuron, simazine, and
atrazine in a silty clay loam and two loam soils. They found
that monuron was leached to the 30- to 46-cm (12- to 18-in) depth
in 4 mo, but that no monuron was detected in this soil layer
after 16 mo. The herbicide might have been leached further,
adsorbed, or degraded. Simazine was leached minimally in the
4 mo after its application, but there was considerable leaching
after 6 mo. In contrast, atrazine was leached to the 30- to
46-cm (.12- to 18-in) depth after 4 mo and to the 46- to 61-cm
(18- to 24-in) depth or greater after 16 mo.
The Teachability of a series of herbicides in soil columns
packed with a Pullman silty clay loam was determined by Wiese
and Davis (156). Upon addition of sufficient water to wet the
soil column to 56 cm (22-in), 2-,3-,6-TBA and PBA were leached
to about 51 cm (20-in). In contrast, esters of silvex,
2-,4-,5-T and 2-,4-D remained in the top 7.6 cm (3-in) of soil.
Other herbicides used were leached to depths between these
extremes.
Field studies of pesticide residues in soils subjected to
natural climatic conditions commonly show that the highest
pesticide concentration is in the surface layer (157, 158).
Once the pesticides are leached to zones of lower organic matter
content, they move at very low concentrations with percolating
waters and do not accumulate. This is because the rate at which
a chemical degrades often limits the extent of actual movement.
Generally, the rapid degradation of many chemicals at their
normal field application rate often is the dominant attenuating
factor. However, this does not imply that the potential trans-
port of pesticides to groundwater, particularly disposal of large
volumes of concentrated solution on land, is of no concern. It
does imply that soil and hydrogeologic conditions must be con-
sidered to evaluate the transport potential.
132
-------
TABLE 19. MOBILITY OF SELECTED PESTICIDES IN HAGERSTOWN
SILTY CLAY LOAM SOIL(153)
Pesticide Mobility Class*
Amiben 5
Atrazine 3
Azinphosmethyl 2
Bromacil 4
Chloroxuron l
Dalapon 5
Dicamba 5
Dichlobenil 2
DDT 1
Dieldrin 1
Diquat 1
Diuron 2
Endrin 1
Fluometuron 3
MCPA 4
Paraquat 1
Propachlor 3
Propanil 2
Propazine 3
Picloram 4
TCA 5
Trifluralin 1
2,4,5-T 3
2,4-D 4
*Based on soil thin-layer chromatography Rf values in
increasing order of mobility: Class 1, 0-0.09; Class
2, 0.10-0.34; Class 3, 0.35-0.64; Class 4, 0.65-0.89;
Class 5, 0.90-1.00. Mobility is measured as "Rf" relative
to the wetting front, so that an Rf of 0.5 means that
over the measured distance the pesticide only moved half
as far as the water. An Rf approaching 0 indicates the
pesticide was immobile.
133
-------
Surface Water Runoff
Movement of agricultural chemicals in runoff has been a
major source of surface water contamination in downstream areas.
Chemicals may be transported as particulate, dissolved, or
bound on eroded soil particles. General factors that influence
runoff and erosion and, thus, influence contaminant transport
in overland flow include rainfall characteristics (intensity,
duration, and seasonal effect) and land characteristics (area,
shape, slope gradient, type of drainage network, soil erodi-
bility, and land usage, management and conservation practices).
The concentrations of contaminants in runoff have been shown
to be related to application rates. In studies conducted by
Barnett et al. (159), concentrations were greatest early in each
storm and decreased with storm duration (159). Runoff losses
of most pesticides in farmland are greatest immediately after
application (159, 160).
Antecedent soil moisture content has a major effect on
surface runoff resulting from rainfall. When the soil moisture
is high, the infiltration capacity is low and surface runoff is
much higher than if the soil moisture content were low.
In a land cultivation operation, the wastes are concentrated
in the soil surface. Thus, the concentration of contaminants in
the runoff water may be sufficiently high to have deleterious
effects on certain trophic levels in the aquatic ecosystem.
Concentrations of trace elements in water considered to be
toxic to aquatic organisms are, in many cases, less than those
considered to be toxic to animals, man, and higher plants.
Concentrations of arsenic, cadmium, chromium, copper, mercury,
nickel, lead, and silver as low as 0.01 ug/ml may have serious
deleterious effects on certain species of aquatic life (161).
Since these tolerances are low, surface runoff of either sedi-
ment or solution into surface water should be controlled.
Surface runoff from wastewater and sludge application sites
must be managed to protect nearby landowners, as well as surface
water quality. Commonly, berms and dikes should be used to
eliminate surface runoff from waste disposal sites.
AIR EMISSIONS
Malodorous emissions from organic wastes can have detri-
mental esthetic and economic effects on a community, as well as
on its residents' mental and physical health (162). Public
opinion surveys frequently identify malodors as the air pollutant
of great concern. Air quality at a land cultivation site can be
impaired by the odors, dust, volatile substances, and aerosols
emitted from waste spreading and incorporation processes. There
134
-------
is no apparent relationship between odors and a specific organic
disease, or toxicity of a gas.
Odor problems from land cultivation of municipal solid waste
are minimal and can be less offensive than the odors emitted at
an active landfill (11), since the waste is incorporated into the
surface soil and undergoes aerobic decomposition. The gases
evolved during aerobic decomposition are primarily C02, HNs, and
volatile products of the waste. During spreading, however, the
putrescible fraction may create odors, particularly if the waste
is left exposed on the surface.
Industrial wastewaters and sludges, in particular those
with high concentrations of organic solids and BOD, may pose a
serious potential for offensive odor nuisances if not properly
managed. Odor problems can begin at the point of initial sludge
handling, and the odor potential can extend for a significant
period of time after actual incorporation of the sludge into the
soil. During spreading and drying, the wastes may undergo
anaerobic decomposition resulting in production of foul smell
from compounds such as alcohols, ammonia, organic amines, mercap-
tans, and organic acids (162). The situation is especially
serious with heavy waste applications on poorly drained soils
during the wet season. Subsurface injection and thorough mixing
of the liquid waste with the soil helps to control odors (Maphis,
personal communication). A number of the commercially available
chemicals for odor treatment are listed by Miner (163). These
chemicals (hydrogen peroxide, hydrated lime, aromatic oils, etc.)
are used to treat the wastes or mask the odors until they
diminish with time, or are sufficiently dispersed. However, once
the wastes are mixed into the soil, the odors are likely to
diminish with time.
Aerosols are micro.scopic-droplets that can be inhaled into
the throat and lungs. Aerosol travel and pathogen survival are
dependent on factors such as wind, temperature, humidity,
vegetative screens, distance, etc. Little is actually known
about the survival of pathogens in aerosols. Tarquin and Dowdy
(164) detected a significant number of pathogenic bacteria
colonies located 122 m (400 ft) downwind of a spray irrigation
nozzle emitting meat-packing wastewater. They also reported a
significant increase in aerosol travel with nozzle pressures.
No form of land treatment of wastewater will completely elimi-
nate the possibility of a pathogenic transfer, but no evidence
suggests that such transfer has been a significant problem in
the numerous operating land treatment systems for food-
processing wastewater (25).
If disposed of by land cultivation operation, industrial
wastes containing heavy metals and organic substances that are
highly toxic, in dust or volatile form, can deteriorate the air
quality. The level of volatile compounds present in the air
135
-------
is not necessarily related to severity of the odor problems.
There is not sufficient data to assess the potential adverse
effect on air quality due to land cultivation practices.
HEALTH AND SAFETY
Harmful effects associated with land cultivation of wastes
can be of a biological, chemical, physical, mechanical, or
psychological nature. It is not easy to distinguish clearly
the effects of waste in general from those of more toxic or
otherwise hazardous waste. For example, human pathogens in feces
provide a biological threat; some industrial wastes pose chemical
hazards; flammable materials involve physical danger of fires
and explosions; and broken glass causes mechanical hazards. Many
other effects, such as psychological and behavioral disturbances
and repercussions, also merit consideration.
In this section, health and safety in land cultivation
practices are discussed with respect to spreading and mixing
of waste, carcinogenic potential from the waste and its degrada-
tion product(s), aesthetics, heavy metals in the food chain,
and disease transmission.
Field Operations
Injuries that occur during handling, spreading, and incor-
poration of waste are potential hazards associated with land
cultivation. Specifically, these hazards include equipment
operations, fires and explosions, dust and aerosols, and odor
problems. Safety precautions and emergency procedures used at
a landfill and farming operations should be applicable to land
cultivation disposal operations.
During land cultivation, fires and explosions could occur,
injuring site personnel. After soil incorporation, some of
the waste materials that are partially exposed can cause fire
hazards resulting from spontaneous or accidental combustion of
flammable materials. Explosions could occur, in part, due to
mixing of incompatible waste materials.
Dust is another problem at municipal refuse disposal sites,
particularly in dry and windy climates. Dust is a potential
health hazard to personnel on the sites and may be a nuisance
to residences or nearby businesses.
Gases and odors generated increase initially during spread-
ing operations and subside as microbial decomposition occurs.
However, in the weathering (spreading) method of disposing
of leaded-gasoline storage tank wastes, the vapors can be inhaled
or absorbed through the skin. At the levels of organically
bound lead (20 to 200 ppm) encountered in the storage tank sludge,
potential lead-in-air hazard could occur during the weathering
136
-------
process, and as an absorptive hazard through the skin during
handling of the material (66). In general, the effect of air
pollution on the health or frequency of illness of site personnel
is not known. At sites where hazardous wastes are land applied,
equipment operators usually wear a dust mask that minimizes
health hazards associated with dust, volatile substances, and
aerosols.
Aesthetics
If not properly managed, application of municipal refuse to
land may result in aesthetic problems from blowing paper and
plastic film, and exposure of residual cans, glass, and plastic.
Unless the waste is shredded finely and thoroughly incorporated
into the soil, the area is unsightly. If the final use of the
land is for pasture, potential hazards to grazing cattle, such
as accidental ingestion of the waste material (plastic, leather,
metals, and rubber), should be determined.
Since waste is not usually cultivated during inclement
weather conditions, it must sometimes be stored at the site for
later disposal. This may create aesthetic problems if the
storage facility and its surroundings are unsightly.
Trace Metals in the Food Chain
Trace metals in the waste which are added to an agricul-
tural soil are not a direct hazard to the food chain until they
have entered or contaminated an edible part of a plant. Some
direct ingestion of recently applied metals or soil containing
large amounts of heavy metals is a special hazard to cattle
grazing waste-treated sites. Application of wastes to fresh
market crops is particularly discouraged.
The roles of a number of micronutrients and trace metals
in plant and animal nutritition have been reviewed (165, 166,
167, 168, 169). Animal diets are often deficient in the essen-
tial trace metals (e.g., chromium, copper, cobalt, manganese,
nickel, zinc, selenium, tin, vanadium, and molybdenum). There-
fore, if wastes containing slightly elevated contents of some of
these nutrients are applied to soils deficient in these trace
metals, the nutritive value of grains and forages used for animal
consumption may be improved.
Trace elements in the waste materials applied to land that
could pose a potentially serious hazard to the food chain
through plant accumulation are cadmium in man and animals, and
selenium and molybdenum in animals. Under proper site management,
other trace metals generally pose relatively little hazard because
of the low solubility of metals in a neutral, well-aerated soil,
.rendering them unavailable to plants and because of limited metal
translocation to the edible parts of plants. Also, concentrations
137
-------
of some metals (e.g., zinc and copper) in plants will exceed
phytotoxic limits prior to reaching toxic levels for most animal
life. Considerable information is available on the effects on
human and animal health of crops containing elevated levels of
the trace metals, particularly of cadmium (166, 168, 170, 171,
172).
A wide variety of crop species accumulate cadmium in
response to Cd concentration of the substrate. Plant content
varies according to species and tissue (173). Cereals and
legumes accumulate less cadmium than do leafy plants such as
lettuce and spinach. Lower cadmium concentrations are generally
found in tubers, seeds, and fruit than in other plant parts.
Plants with cadmium concentrations of 1 ppm or greater in the
edible portion are considered less desirable and unsuitable for
human or animal consumption. The tissues of most crops may
contain undesirable concentrations of cadmium without showing
visible symptoms of cadmium toxicity.
Although selenium is an essential element for certain
animals, the range between deficiency and toxicity is fairly
narrow (168). At levels of 0.05 ppm selenium in the diet,
degeneration of muscle tissue results due to selenium deficiency.
When the diet contains more than 4 ppm, selenium toxicity may
occur. Normal plants contain 0.02 to 2.0 ppm selenium and would
exhibit phytotoxicity at concentrations greater than 50 ppm (165).
Molybdenum is an essential element to plants and animals.
Normal plant concentrations of molybdenum are a few ppm; how-
ever, plants appear to be tolerant to high levels (a few hundred
ppm in tissues). The tolerance of animals to molybdenum varies
with species and age and is dependent upon the status and intake
of copper, zinc, and iron by the animal (172). Cattle are
considered the most susceptible of the farm animals to molybdenum
toxicity. Forages containing molybdenum concentrations exceeding
10 to 20 ppm may produce molybdenosis in ruminants. The symptoms
of molybdenosis are essentially those of copper deficienty, since
the accumulation of copper diminishes as the intake of molybdenum
increases (168). The effect of relatively high concentrations of
molybdenum on copper metabolism is offset by small concentrations
of sulfate in pasture.
Limiting the discussion to cadmium, selenium, and molyb-
denum does not imply that other trace metals are not significant
in the food chain. Cunningham et al. (174) presented data show-
ing that plants would absorb more metals (zinc, nickel, copper,
and chromium) if they were applied as inorganic salts rather than
in sewage sludge. The concentration of heavy metals in the plant
tissues, therefore, depends upon: 1) form and level in the waste
material, 2) application rate, and 3) land management, e.g.,
proper tilling and control of soil pH. If the soil receives more
waste than it can assimilate and/or a waste cultivation site is
138
-------
poorly managed, some of the elements that are considered to be
less hazardous could become a serious hazard in the food chain.
Pesticide and Toxic Organic Residues in the Food Chain
Industrial wastes are usually a mixture of several waste
sources and may contain toxic organic compounds in varying con-
centrations, depending on the type of industry and pretreatment
(see Section 4). When these wastes are land cultivated, it is
conceivable that vegetation grown on the site can be contami-
nated with the toxic constituents in the wastes through surface
sorption and uptake by the plant roots.
Plant surface contamination results from dust, aerosols,
and volatile substances during the application and incorporation
of the waste materials. Sorption by root crops and forage
contamination of pasture crops could pose serious hazards to
humans and animals (175, 176). Persistent potent chemicals
such as hexachlorobenzene (HCB) and polychlorinated biphenyls
(PCB's) are chemically and biologically very stable; thus, they
are particularly significant.
Plant uptake of insecticides, fungicides, fumigants, and
herbicides from soils has been reviewed extensively (176).
Summarized in Table 20 is the knowledge of plant uptake of
selected pesticides from soils. Also indicated on Table 20 is
information on translocation of pesticides from root to differ-
ent plant p'arts, and identification of whether the translocated
compound is the parent pesticide or a metabolite.
Factors controlling uptake (in probable order of importance)
are water solubility and quantity of pesticide in soil, and
organic matter content of the soil. Plant roots are not very
discriminating toward small (molecular weight <500) organic
molecules, except on the basis of polarity. The more polar the
molecule of a insecticide, the more readily it will reach the
root, be absorbed by the root, and be translocated to other parts
of the plant. The contaminated plant may become a potential
hazard itself, depending on the ability of the plant to metabolize
or eliminate the chemical before it is harvested and whether or
not the chemical is translocated to the harvested portion of
the plant.
Beetsman et al. (177) reported that not more than 3 per-
cent of dieldrin from the soil passed into foliage of corn.
Concentrations in root tissue were 20 to 80 times the concentra-
tions in the aerial portions of corn, and the concentration in
the corn shoots was quite constant throughout the growing season.
The organophosphorus insecticides, however, are readily absorbed
by plants growing in soil containing these compounds (176). Some
of these insecticides (e.g., disulfoton, phorate, etc.) are
systemic; they are absorbed by the roots and translocated to the
139
-------
TABLE 20. PLANT UPTAKE AND TRANSLOCATION
OF PESTICIDES FROM SOILS (176)
Compounds found after translocatlon
Insecticide
Aldrin.
Dieldrin
Isodrin
Endrin
Heptachlor
Heptachlor
epoxide
Chlordane
Endosulfan
Toxaphene
BHC
Lindane
DDT
Diazinon
Dimethoate
Disulfoton
Phorate
Parathion
Chloroneb
Arsenic
Lead
Absorbed by
root
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Probable
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Translocated
from root
Yes
Yes
Probable
Yes
Yes
Yes
Improbable
Yes
Improbable
Yes
Yes
Probable
Yes
Probable
Yes
Yes
Probable
Yes
Yes
Yes
Parent
Yes
Yes
Improbable
Yes
Yes
Yes
Unknown *
Yes
Unknown
Yes
Yes
Probable
Yes
Unknown
Yes
Yes
Probable
Yes
Yes
Yes
Metabolites
Yes
Probable
Yes
Yes
Yes
Unknown
Unknown
Unknown
Unknown
Yes
Yes
Yes
Probable
Probable
Yes
Yes
Unknown
Yes
*None, or has never been investigated.
-------
plant top in amounts lethal to certain insects. Kansouh and
Hopkins (178) presented evidence of translocation of diazinon in
bean plants. Concentrations of diazinon in terminal and primary
leaves of the plants increased with time, while root concentra-
tion slowly decreased,
Little is known about the relative plant uptake and
accumulation in plants of hydrocarbons, surfactants, synthetic
polymers, phenols, and persistent organic contaminants; however,
the factors that affect the plant uptake of pesticides and
herbicides in soils should also govern the absorption of these
compounds by plant roots.
Moza et al. (179) investigated the uptake of 2,2'-dichloro-
biphenyl (DCB).- an isomer of polychlorinated biphenyls (PCB's)
by carrot and sugar beet roots in a loamy sand (pH 5.7) that
received 1 ppm (soil basis) of the chemical. Carrots that were
planted the first year contained 0.240 ppm of DCB and 0.012 ppm
of metabolites. Sugar beets that were planted the following
year contained <0.001 ppm of DCB and 0.004 of metabolites. The
current FDA tolerance level of PCB for infant foods is 0.2 ppm.
Since carrots are outstanding in their ability to absorb pesti-
cidal residues from soils, growth of carrots and possibly other
root crops on soils which receive waste containing toxic organic
contaminants does not appear advisable.
Jacobs et al. (180) studied the uptake of polybrominated
biphenyls (PBB's) by orchard grass and carrots grown in a loamy
sand contaminated with 100 ppm (soil basis) of the chemical.
The results showed no uptake or a very low uptake (20 to 40 ppb)
of PBB's by orchard grass and carrots, respectively. Even with
the use of radioactive techniques, no measurable uptake and
translocation of PCB's by soybeans were detected (Fries,
personal communication).
Boxes of sand treated with PCB to achieve 100 ppm concen-
tration resulted in soybean uptake of 0.15 ppm (wet weight
basis) in sprouts after 2 wk growth (181).
Carrots grown on a sandy loam, treated with 100 ppm of
PCB Aroclor 1254 (soil basis), absorbed considerable amounts of
the chemical (up to 42 ppm, wet weight basis) (182). The carrot
peel, comprising 14 percent of the carrot weight, contained 97
percent of the PCB residues. Very little translocation of PCB
occurred in the plant tissue. The translocation of PCB isomers
from soil into carrots under similar circumstances is in the same
order of magnitude as that of the more persistent organochlorine
pesticides (182).
In summary, limited data tend to indicate that foliar
contamination through application or volatilization, rather than
uptake of pesticides and persistent compounds (e.g., PCB's and
141
-------
similar fat-soluble organic compounds), would be the mechanism
by which these potentially harmful compounds enter the food
chain. The danger of contamination of vegetable and grain crops
by these chemicals and their degradation products would probably
exist only for heavily contaminated soils. Cattle grazing on
land contaminated with these chemicals, however, can take up
considerable amounts of the chemicals through ingestion of
contaminated soil particles, rather than through the foliages.
Carcinogenic Compounds
Regulations proposed by the Occupational Safety and Health
Administration (OSHA) would preclude any human contact with
carcinogenic (cancer-causing) compounds in the work place.' Such
compounds include not only those proven to be carcinogenic to
man, but also those which at present are only known to be
carcinogenic to laboratory animals.
Laboratory analyses and epidemiological studies of various
occupational groups have identified over 1,500 potentially
carcinogenic chemical compounds (183). Most of these compounds
are of industrial origin or use; a few are used in medicine. A
chemical produces a carcinogenic effect in a human or animal
via inhalation, oral ingestion, or absorption through the skin.
The effect produced or site of the cancer depends upon the
particular chemical and, to a lesser extent, on the pathway of
body entry.
Carcinogens in Man--
Some compounds known to be or suspected of being carcino-
genic to humans are included in Table 21. These compounds are
divided into five classes (polynuclear aromatic hydrocarbons,
aromatic amines, alkylating agents, chromate salts, and inorganic
arsenicals) and three specific chemicals (nickel carbonyl,
asbestos, and benzene). Benzene, although not a proven carcino-
gen, is highly suspect. Evidence for the carcinogenic effect
of these compounds in man is, in all cases, based on epidemio-
logical studies of selected populations and industrial occupa-
tion groups. Cancer thus detected in humans is generally chronic,
occurring only after relatively long-term exposure to these
compounds.
Carcinogens in Animals--
A large number of chemicals have been found to produce
cancer in laboratory animals. A list of selected chemicals are
given in Table 22. Although no proof exists that man is similarly
affected, the utmost caution should be taken in exposing humans
who are working with and disposing of these chemicals.
Also presented are the effects of the chemicals; laboratory
animals demonstrating the carcinogenic impact, pathway (method
of administration of the chemical); and industrial uses of the
142
-------
TABLE 2T. POSSIBLE CARCINOGENS IN MAN (183)
CO
1.
2.
3.
4.
5.
6.
7.
8.
Compound
Polynuclear aromatic hydrocarbons
. Soots
. Pitch, coal tar and products,
creosote
. Mineral, petroleum and cutting
oils
. Benzo (a) pyrene
Aromatic amines
. 2-nephylamine
. Benzidine, 4-aminobiphenyl ,
4-ni trobi phenyl
. auramine, magenta
Alkylating agents
. Melphalon, busulfan
. Chlornaphthazine
. Mustard gas
. Bis (chloromethyl) ether
. Dimethyl sulfate
. Methyl chloromethyl ether
. Vinyl chloride
Nickel carbonyl
Chromate sal ts
Inorganic arsenicals
Asbestos
Benzene (?)
Areas Affected
skin, lungs
skin, lips, lungs
skin
lungs
bladder
bladder
bladder
leukemia,
lymphomas
bladder
lungs
lungs
lungs
lungs
lungs
lungs, nasal
sinuses
lungs, nasal
sinuses
skin
lungs
leukemia
Uses
Dyes intermediate,
industrial ariti-oxidants
Dyes, fungicides
Chemotherapeutic agents
Chemotherapeutic agents
War gas
Ion exchange resins
intermediate
Methyl ating agents
Products from nickel
refining
Medical preparations,
pesticides
Form
Powder
Viscous liquids
Viscous liquids
Insoluble crystals
Powder, liquid, gas
Crystals or powder
Liquid or crystal
Soluble dyes
Gas
Volatile liquid
Liquid
Liquid, decomposes in HgO
Liquid or gas
Volatile liquid
Fibers
Liquid
-------
TABLE 22. CARCINOGENS IN ANIMALS (183)
Compound
Acetamide
Aminotriazole
0-Tolidine
Dianisidine
3, 3'-dichloro-ben-
zidine
Methyl ene dianiline
3, 3'-dichloro-4, 4'
diaminodiphenyl
methane
Heridine
2, 4-Toluenediamine
4-Chloro-o-toluidine
Carbon tetrachloride
Chloroform
Dimethyl carbamyl
chloride
1, 1 -Dimethyl hydrazine
Dioxane
Ethyl carbonate
Areas
liver
liver
Affected
and thyroid
bladder
skin,
lower
liver
liver
liver
1 i ver
liver
liver
bladder,
intestine
and lungs
and lungs
skin and lungs
lung,
liver
lungs
blood vessels
, nasal areas
Animal ^
R
R, M
R, M
R
R, M
R
R
R, M
R
M
M
M
M
H
R
M
Pathway #
0
0
0
O&I
O&I
0
0
0
0
0
S&I
W
Uses
Solvent, textile treating and dyeing,
plasticizers
Herbicide, photographic reagent
Dye industry intermediate
Dyestuff and polyurethane intermediate
Dyestuff and polyurethane intermediate
Epoxy resin hardness, polyurethane intermediate
Epoxy resin and isocyanate
Polymer curing agent
Dyestuffs
Dye ingredient, polyurethane foam ingredient
Dyestuff intermediate, bird control agent
Solvent, degreasing agent
Solvent, cleansing agent, intermediate
Synthesis of herbicides, pesticides and
anthelmintic drugs
Rocket fuel, synthetic intermediate
Sol vent
Stain solvent, dye intermediate
(Continued)
-------
TABLE 22 (continued)
en
Compound
Ethyl ene inline
Propylene inline
Ethylene thiourea
Glycidalehyde
Hydrazine
Accel lerene
N,4-Dinitrozo-N-
methyl aniline
beta-Propiolactone
Propane sultone
Thioacetamide
Thiouracil
Thiouracil
Areas Affected
liver and lungs
breast, brain,
ear duct, leukemia
thyroid, liver
skin
liver, lung,
lymphomac
esophagus, stomach
brain
liver
thyroid
thyroid
Animal^
M
R
R, M
M
M
R
R
M
R
Pathway *
0
0
0
S
W
0
S
0
0
0
0
Uses
Resin intermediate, textile and paper
finishes
Rubber processing
Glycerol intermediate
Agricultural and medical intermediate
reducing agent
Dye intermediate, rubber chemical
Rubber and plastic additive
f
Sterilizing agent in labs and hospitals
Several proposed
Photography, rubber accelerators, metal
polish
*No evidence has been established that these compounds are carcinogenic in man.
tR = Rats, M = Mice.
#0 = Oral, in food, I = Injection.
S = Skin application.
W = Oral in drinking water.
-------
chemical. The various chemicals produce leukemia and tumors in
the liver, lungs, thyroid, bladder, lower intestinal tract, skin,
breast, brain, ear duct, blood vessels, esophagus, and stomach.
Industrial Uses of Carcinogenic Chemicals--
Chemicals known to be carcinogenic have a wide range of
industrial uses. Dyes are the most common carcinogenic chemicals
listed. The rubber and plastic industries are users of six of
the animal carcinogenic chemicals. Auramine and some inorganic
arsenicals, as well as three animal carcinogens, are also used
in the production of certain pesticides.
Carcinogenic chemicals are used by several other industries
and processes, such as those that manufacture ion exchange and
epoxy resins, photographic chemicals, rocket fuel, and drugs, and
those involved in nickel refining, textile treating, metal work-
ing, degreasing, paper finishing, glycerol manufacturing, and
wood preserving.
Disposal Precautions--
Personnel dealing with the collection, transport, or dis-
posal of industrial wastes should be protected to the same extent
as personnel working directly with the chemicals. This protection
required that industrial waste containing significant quantities
of any known carcinogen not be disposed by land cultivation. If
land cultivation of such an industrial waste is planned, pre-
treatment to remove the carcinogen or to alter the chemical to a
noncarcinogenic form will be necessary.
Placing human health and safety restrictions on the land
cultivation of industrial wastes is complicated by the pheno-
menon known as cocarcinogenesis. A cocarcinogen is a material
that has minimal or no cancer-inducing ability by itself, but
can increase the effectiveness of a carcinogen when the two are
administered together. There is also a danger that the mixture
of two chemicals can be carcinogenic, while the two individual
chemicals by themselves have no carcinogenic effects. Because
of these possibilities, it is extremely important to avoid
indiscriminate human exposure to substances with unknown bio-
logical effects.
Pathogens
From a public health aspect, one of the most immediate
and serious questions raised in land cultivation practice for
waste materials is the potential for the transmission of patho-
gens, including bacteria and viruses. Transmission can
potentially occur via: 1) groundwater, 2) aerosols, 3) physical
contact with the waste or contaminated crop, or 4) the food
chain. The disease-producing organisms do not have to be present
in the host material because the environment contains spores,
bacteria, viruses, insects, vermin, and other vectors awaiting
a favorable growth condition.
146
-------
In a field experiment in which tomato cannery waste was
spread on soil, excessive fly infestation led to a temporary
shutdown of the project (Ayers, personal communication). Hart
et al (11) encountered similar problems in their study of land
spreading of municipal raw refuse; however, mixing the waste
materials with the surface soil alleviated the problem.
Municipal raw refuse has been shown to contain viable
pathogens that may pose a health hazard to animals and humans
(51, 184). Included are the bacterial pathogens (salmonella,
shigella, mycobacterium, and V1_bri_g sp.), the infectious
hepatitis virus, enteroviruses and adenoviruses, protozoans
such as Endamoeba histolytica, and certain pathogenic fungi
and fungal allergens.
Because survival time in soils is limited, pathogens
generally do not pose a long-term threat to the soil as a
resource. Many of the pathogenic microorganisms can survive in
soils for a few days, although some may survive for several
months (185). Survival time in the soil for a given micro-
organism is generally prolonged by low temperature, high water
content, and neutral pH, and may also be affected by the organic
matter content of the soil. It has been reported that fecal
coliform organisms rarely penetrate as deep as 1.2 m (4-ft)
of an unsaturated soil, and horizontal movement through uniform
soils is generally limited to 30.5 m (100-ft). Application of
wastes on soil generally decreases pathogen survival and
virulence with time (186). The threat to groundwater is there-
fore minimized.
It has been established that fruits and vegetables,
especially root crops, can become surface contaminated by patho-
gens and may pose a threat to human health if consumed raw
(185, 186). Research is needed in the general areas of survival,
movement, and possible inactivation of viruses through adsorption
or microbial antagonism. This research should clearly establish
the extent of a potential pathogen hazard, including long-term
health effects, in relation to waste application to different soils
147
-------
SECTION 12
SITE MONITORING
Land used for waste renovation or disposal must be moni-
tored so that the environment is adequately protected. Monitor-
ing, in the broad context, includes observing operation perfor-
mance, checking the quality of potentially affected natural
systems, and observing and recording environmental impacts as
quality changes occur. It is a tool for developing preventive
maintainance procedures. In land cultivation, monitoring should
be used to confirm the predictions and judgments made during
project development and design with respect to the natural sys-
tems. Monitoring should be employed to expand understanding of
operation performance; it should not be used as a substitute for
understanding the many interrelated physical, chemical, micro-
biological, and hydrologic factors within any project prior to
implementation.
The elements and/or constituents in industrial wastes
which are considered as pollutants are listed in Table 23; how-
ever, no single waste would likely contain all these pollutants.
The constituents or parameters to be monitored will depend, to
a large extent, on their concentrations and waste properties and
on the purposes of land cultivation, i.e., utilization or dis-
posal of the waste.
Soil, groundwater, surface runoff, vegetation, and air
quality are specific areas which should be considered for moni-
toring at the land cultivation site.
SOIL MONITORING
The soil at the land cultivation site should be physically
and chemically characterized during project design. The monitor-
ing program developed should identify changes in these charac-
teristics to avoid permanent or irreversible soil damage.
Recent studies show that chemical analysis of core samples
from waste disposal sites permits positive identification of any
chemical constituent within the soil profile (188). This is
true regardless of whether the chemicals are present in preci-
pitated form in the zone of soil incorporation, are retained on
soil particles in the semi-saturated fringe, or are dissolved
in groundwater within the zone of saturation. Chemical analyses
of soil core samples are usually faster, easier, and more
148
-------
TABLE 23. SELECTED POLLUTANTS WHICH MAY BE PRESENT IN
INDUSTRIAL WASTE STREAMS AND RESIDUES (187)
Alkalinity
BOD
COD
TS
TDS
TSS
Ammonia
Nitrate
Phosphorus
Turbidity
Fecal Coliform
Acidity
Hardness, Total
Sulfate
Sulfite
Bromide
Chloride
Fluoride
Alurnin urn
Boron
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Magnesi urn
Manganese
Mercury
Nickel
Selenium
Sodium
Vanadium
Zinc
Oil and Grease
Phenols
Polychlorinated biphenyls
Surfactants
Algicides
Chlorine
Organics specific to
organic synthesis
149
-------
economical than analyses of groundwater samples collected from
observation wells.
By determining distribution of a chemical constituent or
contaminant in soil (concentration vs. soil depth), it is possible
to discover whether the pollutant is retained in the surface soil
or moving slowly to lower soil depths (189). This information
can be used as an early warning of pending groundwater
contamination.
Core Sampling
The number of core samples and sampling depths selected
will depend on the variability of the soil, allocated budget,
the degree of accuracy desired, particular constituents to be
determined, waste management, and the general overall purpose of
investigation. Cultivated soils are generally more variable than
virgin soils, and saline and alkali soils are extremely variable.
There is no set standard for soil sampling suitable for all
studies. The movement of most waste constituents in soil is a
slow process, except in very sandy soil with high rainfall. Thus,
for most land cultivation sites, yearly sampling of surface (0 to
30 cm) and subsurface (30 to 60 cm, 60 to 100 cm) soils will
suffice. Petersen and Calvin (190) have discussed field sampling
with respect to statistical validity. The following points are
well established:
A series of cores of equal diameter and comparable
depth taken according to some systematic grid
layout of the area should be composited.
Separate soil cores should be analyzed, or replicate
sets of composites should be made to determine
statistical significance of results on the final
composite.
a Separate composite samples representing different
segments of the soil profile or root zone should
be taken.
Contamination from soil surface materials (crop
residues, sludges, fertilizers, etc.) should be
avoided as well as contamination of one soil
depth with that of another.
t In an area to be sampled at successive intervals,
a map should be made that shows initial sampling
points. Subsequent samples should be taken at
short, but definite distances away from the
preceding sampling point.
150
-------
t Composite samples provide only an estimate of
the mean of the population from which the samples
forming the composite are drawn.
Samples taken prior to waste application from the disposal
area or from a control area where no waste has been applied
should be used to establish baseline date for comparison. Soil
characteristics for the control should be similar to those in
the disposal area. Samples should be air dried (at temperatures
less than 40°c), ground, and passed through a 2-mm sieve as soon
as possible after collection. Chemical analysis is .generally
performed on the air-dry samples, and the concentration is ex-
pressed on an oven-dry (110°C) basis (191). However, some
analyses such as Cr and nitrogen should be refrigerated and
analyzed as soon as possible.
Soil Analyses
The physical properties of the soil are seldom evaluated
in the monitoring program at most land cultivation sites once the
field operation has been implemented. This is based on the
assumption that these properties will not be adversely affected
if proper site management practices are followed.
The primary objective of soil analysis is to monitor the
accumulation as well as the vertical and horizontal movement of
potential contaminants applied in the waste. A list of the
parameters to be monitored prior to and following waste appli-
cation is presented in Table 24. Such factors as soil pH, CEC,
organic matter content, and soluble salts (EC), which affect
the migration of contaminants are also included. Monitoring
of soluble salts is also important when the site is planted to
grasses or agronomic crops. A generalized index of crop
sensitivity to soil salinity is presented in Table 25.
Field measurements of aeration status (oxygen tension
and oxidation-reduction potential or Eh) are useful in deciding
if favorable conditions exist for aerobic decomposition of
the waste applied. However, these measurements are not included
in site monitoring since collection of reliable data from field
installations is difficult. Based on the chemistry of water-
logged soils, the aeration status can be predicted by various
chemical species present in wet soil. Poor aeration+is indicated
by disappearance of NOrj-N and the accumulation of NHzi-N, Fe2t,
and Mn2+. Odorous gases such as CH4 and H£S also indicate
extremely reduced conditions.'
Generally, total analysis of the constituents of concern
by extraction with concentrated acids is sufficient to determine
the extent of movement in soil. As yet, no standard extraction
procedures have been established to measure total concentration
of various elements or constituents in soils treated with waste
151
-------
TABLE 24. PARAMETERS TO BE MONITORED IN SOIL PRIOR TO AND AFTER WASTE APPLICATION
en
ro
Parameter
PH
CEC
Organic matter
Soluble salts (TDS or EC)
Total N
NO^-N
NH|-N
Water-soluble or acid
extractable ortho-P
Water-soluble Ca, Mg, Na, K
Heavy metals (Zn, Cu, Pb, Cd, Ni)
B, Se, Mo, Hg, As, Cr
Prior to Application
Yes
Yes
Yes
Yes
Yes*
Yes
Yes
Yest
Yes
Yes
After Application
Yes
Yes
Yes
Yes*
Yes
Yes
Yest
Yes!
Yes
If suspected to be
Pesticides
Toxic, carcinogenic compounds
Pathogens
*If total N is low, omit inorganic N.
tlf total P in waste is low, omit soil P.
#If EC or Na content in the waste is high,
determine sodium adsorption ratio (SAR).
high in waste
If suspected present
If suspected present
If suspected present
-------
products. In soil analysis, various forms of metals have been
proposed by use of different extractants (191). These include:
1) DTPA, 2) water-soluble or dilute acid-soluble, 3) NH4OAc
(exchangeable), and 4) easily reducible (189, 191). The concen
trations present in these forms are used to establish the
availability or potential for plant uptake and migration.
TABLE 25. RESPONSE OF CROPS GROWN IN SOILS
OF VARYING SALINITY LEVELS*
Salinity, EC Crop Responses
mmhos/cm at 25°C
0-2 Salinity effects mostly negligible.
2-4 Yields of very sensitive crops may
be restricted (most fruit crops,
radish, green beans).
4-8 Yields of many crops restricted.
o 16 Only tolerant crops yield satis-
factorily (e.g., spinach, barley,
cotton, sugar beets, most forage
crops).
>16 Only a few very tolerant crops yield
satisfactorily (e.g., saltgrass,
alkali sacaton, Bermuda grass).
*Adapted from Richards (192).
GROUNDWATER MONITORING
A major concern of land disposal of wastes is the possible
contamination of groundwater (193). This is a significant
concern for landfills, but is of lesser concern for land culti-
vation. This concern is due to the elusive nature and the long
duration of groundwater contamination. In addition, it may take
decades or centuries and large financial expenditures to remedy
the damages. Groundwater monitoring is, therefore, widely
practiced by site operators.
Monitoring Wells
Monitoring wells must be designed and located to meet the
specific geologic and hydrologic conditions at the site.
Consideration must be given to the following (194):
Geological soil and rock formations existing
at the specific site
153
-------
Depth to an impervious layer
Direction of groundwater flow and anticipated
rate of movement
Depth of seasonal high water table and an
indication of seasonal variations in ground-
water depth and direction of movement
Nature, extent, and consequences of mounding
of groundwater,1 which can be anticipated to
occur above the naturally occurring water table
Potable and nonpotable water supply wells
Other data as appropriate to the specific
system design.
It may be necessary to establish baseline site groundwater
conditions through installation of simple observation wells prior
to the actual selection of locations and depths for permanent
monitoring wells. No "rules of thumb" exist to determine the
degree of monitoring intensity. Therefore, the best procedure to
determine the number of wells to be installed is to develop a
joint agreement with the responsible regulatory agency after a
complete review of the site geology has been made.
Various aspects of geologic evaluations, layout of monitor-
ing wells, well design, installation, and groundwater sampling
have been discussed by Diefendorf and Ausburn (195).
Groundwater quality should be monitored immediately below
the water table surface near the application site, as polluted
materials entering the groundwater system may remain in the upper
few feet of the water table (195). With .increased distance from
the site, the depth of sample withdrawal from within the ground-
water system may need to be increased, or sampling at multiple
depths may be required to assure interception of the potentially
affected groundwater. The need for sampling at more than one
depth will depend upon geologic conditions and distance from the
source of pollution. Definition of the flow system with depth
will be necessary to properly determine the depth to be monitored,
especially when mounding is superimposed on the existing system.
Groundwater monitoring wells must be located to detect any
influence of waste application on the groundwater resource. A
minimum of one groundwater monitoring well must be provided in
each direction of groundwater movement near the source of
pollution, with adequate consideration given to possible changes
in groundwater flow due to mounding effects. The orientation and
spacing of multiple wells should be determined by hydrogeologic
154
-------
conditions at the site. All monitoring wells should be securely
capped and locked when not in use, to avoid contamination.
Water level measurements should be made with reference to
a permanent reference point, using U.S. Geological Survey data.
Measurements should be made under static water level conditions
prior to any pumping for sample collection.
Sample Collection--
To establish a suitable data base for reference to back-
ground conditions, under normal climatic conditions, one compo-
site sample should be collected monthly from each monitoring well,
In certain cases, background water quality adjacent to the site
may be influenced by prior waste applications. In these cases,
water quality should be analyzed by new monitoring wells or by
existing wells in the same aquifer beyond the area of influence.
Blakeslee (194) recommended that samples be collected
monthly during the first 2 yr of operation. After the accumu-
lation of at least 2 yr of groundwater monitoring information,
sampling frequency may be modified. He also recommended the
following sampling procedures:
t A measured amount of water equal to or greater than
three times the amount of water in the well and/or
gravel pack should be exhausted from the well before
sample collection. In the case of very low permea-
bility soils, the well may have to be exhausted and
allowed to refill before a sample is collected.
Pumping equipment should be thoroughly rinsed before
use in each monitoring well.
t Water pumped from each monitoring well should be
discharged to the ground surface away from the wells
to avoid recycling of flow in high permeability soil
areas.
Samples must be collected, stored, and transported
to the laboratory in a manner to avoid contamination
or interference with subsequent analyses.
Sample Analysis--
Preservation of samples without some change in the chemical
and biological activity is almost impossible. Consequently,
analyses should be completed as soon as possible after the sample
is obtained. To keep changes in the sample to a minimum during
storage, the guidelines by the U.S. EPA (196) or the American
Public Health Association (197) should be followed. It is
important to note that a single method of preserving samples is
not adequate for all analyses.
155
-------
Water samples collected for background water quality at a
land cultivation site should be analyzed for the following:
Chloride
Soluble salts (electrical conductivity
or total dissolved solids)
pH
Total hardness (if used as drinking water)
Alkalinity (if used as drinking water)
Nitrate nitrogen (if waste is high in
total nitrogen)
t Any trace elements, pathogens, or toxic
substances found in the applied wastes
at elevated concentrations. ,
After adequate background water quality and initial site
operation information has been obtained, a minimum of two compo-
site samples per year, obtained between waste applications,
should be collected from each well and analyzed for the above
constituents. It is recommended that all water samples should
be analyzed for easily leached chloride (or nitrate) and elec-
trical conductivity (EC) as indicators of changes in groundwater
quality resulting from the waste applied. If significant changes
are noted in chloride and EC levels, samples should immediately
be analyzed for other parameters to determine the extent of water
quality deviation from background levels. Meanwhile, waste
application should be halted until the source of buildup is
identified.
RUNOFF MONITORING
Runoff is usually controlled at a land cultivation site by
disking frequently, contouring to the slope of the land, and
providing dikes at the low points of the site to pond the
water. However, if runoff occurs often and in appreciable
amounts, monitoring facilities must be provid-ed to obtain repre-
sentative water samples and corresponding flow measurements for
quantitative evaluation. Sampling should be done throughout the
entire period when runoff is occurring.
The sediment and water fractions of runoff samples should be
analyzed for nitrogen, phosphorus, and any heavy metals, pathogens,
or toxic substances that are present in significant concentra-
tions in the applied waste. Total loss of any constituent
analyzed can be computed using the following equation (198):
RL = Z (R. x C.) x K
i = l n n
where RL is the total runoff loss (g/ha);
156
-------
R. is the volume (m ) of runoff for any segment i of the
storm and is positively related to rainfall;
C. is the concentration (mg/1) of the constituent
measured in each runoff segment;
n is the number of segments; and
K is a constant (ha ) for the land cultivation
site, with size in ha
A typical example is given below:
During the month of July, runoff occurred 3 times at a
5-ha land cultivation site, and the following information was
collected:
RI = 1,000 m3 R2 = 1,500 m3 R3 = 500 m3
C, = 3.0 mg/1 C, = 2.0 mg/1 C, = 1.5 mg/1
* £, Q
Where C,, C2, and C3 are nitrate-N concentrations in
samples collected from 85 to 90 percent of the 3 total runoffs
with volumes R,, R2, and R3, respectively.
Total nitrate-N losses in the runoff can be computed
as follows:
wn~-N = (Q r + P r + R r \ K
II V 13 IM \l\i*Vi ' l\ n U A ~ rV^.Wn/ "
= (103 x 3.0 + 1.5 x 103 x 1.5)* 5
= 1,350 g/ha
= 1.35 kg/ha.
VEGETATION MONITORING
The vegetation produced on the land cultivation site may
be the most sensitive and meaningful indicator of the impact of
waste applied to the site. Monitoring during the growing season
would signal an accumulation of heavy metals or other toxic
constituents in soil (199). The warning provided by timely
monitoring would enable the operator to introduce corrective
measures or, if necessary, to discontinue waste application.
The purpose of vegetation monitoring can be one or all of-
the following, depending on waste management practice and the
vegetation present:
Determine the nutrient or metal removal capability
of the vegetation.
157
-------
Determine if certain nutrients or metals have
reached phytotoxic concentration and if the
harvested portions are suitable for consumption by
animals or humans.
Ascertain the quantity of nutrients or metals leaving
the field in harvested portions of crops, or being
left on the field as unharvested plant residue.
If and when agricultural monitoring is necessary, plants
can be regarded as an appropriate indicator of harmful levels
for certain but not all constituents. Plants may not give
accurate information on carcinogens, viruses, and other patho-
gens, all of which may affect human health but would possibly
have little effect on plant nutrition. Periodic analysis of the
harvested portions of plants will, in most instances, indicate
the rate and increase of metal availability to the plants; it
will also signal the approach of harmful levels well in advance
of permanent damage to either soil or crop. Interpretations of
such an analysis must recognize normal seasonal differences in
plant composition and possible sampling errors. As further toxi-
cological information is obtained, the plant analysis can be
interpreted with increasing precision in terms of potential
toxicity of the plants to animals and humans.
Jones and Steyn (200) have discussed the specific portion
of the plant and the number of plants to be sampled at certain
stages of growth for plant nutrition studies. In general,
mature leaves which are found just below the growing tip on main
branches and stems are usually preferred for sampling. Sampling
is normally recommended just prior to or at the time the plants
begin their reproductive stage of growth. A plant portion that
is soil or dust covered, damaged by insects, mechanically injured,
or diseased should not be sampled. Collection of root samples
which do not have a contamination problem is extremely difficult
and is not warranted, except for a few root crops. In monitoring
for a land cultivation site, plant accumulation of the concerned
elements or toxic constituents is of greater significance than
the plant nutrient status. As a result, the harvested or edible
portions are generally analyzed to determine the suitability of
the vegetation for consumption.
Plant analyses have three limitations where monitoring
of heavy metals and other toxic constituents is concerned.
First, although the analyses indicate the approach of a hazardous
level for the crop analyzed, the level attained may already be
toxic to more sensitive crops. Second, analyses of tops and
roots are generally required to adequately diagnose all toxici-
ties. (Note that collection of uncontaminated roots is extremely
difficult.) Third, plant analyses usually cannot be used to
indicate the level of soil nitrogen that may lead to ground-
water contamination.
158
-------
The plant processing procedure typically includes (190,
200): 1) washing the tissues in a 0.1- to 0.3-percent detergent'
solution followed by rinsing them thoroughly in de-ionized water;
2) drying in a forced-draft oven at 65°C for several days; 3)
grinding by hand or in mills; and 4) storing in sealed polyethy-
lene bags, preferably under refrigeration. Total elemental
analyses on plants rather than selective extraction procedures
are conducted. If trace elements are assayed, the washing
solutions, sample processing equipment, and reagents used must
be checked periodically for contamination problems.
AIR MONITORING
The air quality of most land cultivation sites is seldom
monitored, unless the waste contains putrescible material that
is likely to create odor problems. Since wastes containing
highly toxic substances in gaseous or dust form are not suitable
for land cultivation, and wastes that are land cultivated are
either mixed with soil material or subsurface injected, air moni-
toring may not be mandatory at existing land cultivation sites.
In summary, it is recognized that land cultivation sites
must be monitored to adequately protect the environment. The
constituents or contaminants to be analyzed in a monitoring
program are highly waste specific. The waste material applied at
a site is like the raw material in a manufacturing process: to
be assured of an acceptable "product," the raw material must be
of known and "acceptable" quality. This requires periodic
monitoring of the waste.
For visited sites with a monitoring program, groundwater
receives a great deal more attentien than soil, crop, or air
emission. This is because groundwater monitoring is mandated by
regulatory agencies for operating a land cultivation site. Moni-
toring of heavy metal buildup in soil or of crop quality is
practiced at a few sites, while monitoring of air quality is
usually not practiced. As a result, very little is known about
the air quality at and around the land cultivation sites.
The problems of adequate well placements, sample collection
procedures, and data interpretation seriously hamper the
effectiveness of groundwater monitoring. In monitoring a land
cultivation site, more emphasis should be placed on the collection
and analyses of soil samples taken at incremental depths.
159
-------
SECTION 13
SITE CONCEPTUAL DESIGN
The site conceptual design presented below is a synthesis
of the data obtained from six case study site investigations an<
related background information. The conceptual design is inten-
ded to be used as a planning tool and information vehicle for
persons concerned with consideration of land cultivation as a
disposal alternative. It is not intended to provide all infor-
mation necessary to totally design and manage a land culti-
vation facility.
There is no one "typical" land cultivation facility.
Therefore, a hypothetical example site is used as a basis for
the conceptual design. Pertinent characteristics of the example
site are described so that users of the conceptual design can
identify differences between the example site and corresponding
characteristics of their actual site. This enables the user
to adjust the technical and economic factors in the conceptual
design to reflect his site-specific conditions.
BASIS FOR DESIGN
For the conceptual design presented, the basic management
objective is assumed to be the application of waste materials
to the soil so that the soil can assimilate the wastes and to
contain the wastes and potentially harmful by-products on
the site.
It is assumed that the site is operated commercially, and
not by the waste producer. Wastes from more than one source can
be expected. It is important that the chemical composition of
all input waste streams be analyzed and evaluated to ensure that
they may be safely mixed, both in storage lagoons and in the soi
An additional assumption is that transport of sludge to the site
is not part of site costs; rather, it is an expense item borne
by the waste generator. As is generally the case, the state in
which the hypothetical disposal site is located does not have
specific regulations pertaining to land cultivation disposal.
Application of industrial waste to the site is evaluated by the
appropriate state agency on a case-by-case basis. State agencies
generally prefer land cultivation sites to have a maximum slope
of 5 percent. The minimum desirable depth to groundwater is
typically considered to be 4.6 m (15 ft), although this criterion
may be modified depending on the quality and uses of groundwater
160
-------
and the types of overlying soils. It is also preferred that the
soils be deep - greater than 1.2 m (4 ft) - and moderately permeable.
Waste and site characteristics assumed for the conceptual
design are summarized in Table 26. The developed design is
based on land cultivation of a potentially hazardous organic
waste (201). The waste is a sludge resulting from treatment of
industrial wastewater. To provide cost comparisons for different
rates of land cultivation disposal, the conceptual design con-
siders three annual disposal rates: 1,000, 2,000, and 4,000
dry t (1,100, 2,200, and 4,400 tons).
A sketch of the hypothetical land cultivation site is shown
in Figure 25. The topography of the site is such that slopes
range from 1 to 3 percent, with an average slope of approximately
2 percent. The site is part of an open drainage system, which
is typical of most humid and sub-humid regions. As a result, the
movement of sediments and soluble materials from the site to
neighboring water courses is possible. However, the site can
be modified to control runoff.
Soils at the hypothetical site are medium textured, such as
silt loam, with a clay content ranging from 10 to 25 percent,
varying with depth. The soils are moderately well drained and
have an available moisture holding capacity of approximately
15 percent. The site is assumed to have been cleared and used
for pasture for several years.
Land area required depends on the waste application rate.
Waste application rates normally must be determined on a case-
by-case basis, depending primarily on the soil type, waste
decomposition rate, and the concentration of degradable and non-
degradable toxic constituents. The assumed waste characteristics
are such that an application rate of 113 dry t/ha (50 dry tons/ac)
is appropriate for a useful site life of 20 yr. At this appli-
cation rate, the productivity of the site for agricultural crops
after 20 yr of land cultivation may not be irreversibly impaired.
It is preferable, however, that the site be used solely for
disposal purposes; no crop is grown during or after completion of
disposal operations to prevent introduction of toxic substances
into the food chain.
A surface and groundwater monitoring program is a necessary
part of any land cultivation design. To adequately monitor
surface water near or adjacent to the site, two samples should
be taken at quarterly intervals. One sample point should be
located upstream from the site and the other downstream.
The number of wells required to adequately monitor ground-
water at the site depends on the complexity of the subsurface
hydrology. For this hypothetical site, four wells are specified.
Two wells are located at the upstream boundary of the site to
161
-------
TABLE 26. BASIS FOR DESIGN
CTl
Waste characteristics:
Potentially hazardous industrial wastewater treatment sludge.
t Five percent solids as disposed.
Does not include domestic sewage.
Generation rates of 1,000, 2,000, and 4,000 dry t (1,100,
2,200, and 4,400 tons) per year at 5 percent solids.
Site characteristics:
Scope from 1 to 3 percent, averaging 2 percent.
Silty loam soil at least 1.2 m (4 ft) deep.
Soils are moderately well drained, with a moisture holding
capacity of approximately 15 percent.
Average precipitation of approximately 100 cm (40 in) per year.
At least 4.5 m (15 ft) to groundwater.
Application rate:
t 113 dry t/ha (50 tons/ac) per year.
Site monitoring:
Six water samples taken quarterly
- Two surface water samples
- Four groundwater samples
Jwo soil samples taken quarterly
- One surface 0 to 30 cm (0 to 12 in) depth or within plow layer,
- One subsurface 30 to 60 cm (12 to 24 in) depth.
Ten water quality parameters measured in each sample.
-------
STORAGE
LAGOON
7//7//////////;/////ffJ7777^////////////^^
DIKE
Figure 25. Artist's conception of land cultivation site
-------
establish background water quality. Two wells are located down-
stream from the site to establish the distribution and impact
of localized contamination (if any) on water quality in the
aquifer. More wells would be desirable, but cost considerations
will usually indicate that a plan be developed to ensure most
effective coverage with the least number of wells.
The suggested soil monitoring program entails taking 10
soil samples each at the 0 to 30 cm (0 to 12 in) and 30 to
60 cm (12 to 24 in) depths prior to the first waste application
and at quarterly intervals thereafter. The samples at each
depth are composited, processed, and analyzed. Data obtained
for the soils which have received waste can be compared with
the results for the controls (samples obtained prior to first
waste application). This comparison will indicate any accumu-
lation and the extent of vertical migration of waste constituents
(e.g., heavy metals) beyond the plow layer.
The specific analytical requirements of the water monitor-
ing program depend on the composition of the waste being disposed.
It is recommended that the following parameters be monitored for
all waste types:
Total dissolved solids (TDS) or
soluble salts (EC)
TOC
pH
Sulfates
Chlorides
Nitrate-nitrogen
Iron.
Other parameters of concern such as sodium, boron, selenium,
molybdenum, heavy metals, and toxic organic compounds should
be included in the water and soil monitoring programs if these
elements are present in significant concentrations in the
incoming waste. All analytical determinations can be performed
by a contract laboratory.
Quarterly water sampling should be adequate for monitoring
site performance. Such a sampling frequently has been typically
employed by numerous land cultivation site operators and state
regulatory agencies.
SITE DESIGN
Since the site's topography is gently sloping and relatively
flat, substantial grading is not required to facilitate land
cultivation operations. The site has been used previously for
pasture, so substantial clearing is unnecessary. Uncontrolled
sheet runoff from the site's surface during periods of intensive
rainfall could result in contamination of adjacent surface waters.
164
-------
For this reason, construction of a system of berms and runoff
collection ditches around the site perimeter prior to initiating
land cultivation activities is specified. These ditches will
divert the first 2.5 cm (1 in) of runoff to a containment basin
for later application to the site during dry weather. This sur-
face drainage system will eliminate standing water in the
cultivated area, thereby ensuring that aerobic processes neces-
sary for waste decomposition are maintained. Additional runoff
(after the first 2.5 cm) will be diverted through a coarse gravel
filter for sediment control before discharge to surface waters,
if analyses indicate the quality of the discharge meets
appropriate regulations.
Liming the soil to a pH range between 6.5 and 7.5 is
necessary if the soil is strongly acid. Nitrogen fertilizer
should be applied if the waste is highly carbonaceous (carbon
and nitrogen ratio >30) to speed waste decomposition.
An access control fence is placed outside the disposal
area's ditch/berm and within 30 m (100 ft) of the site perimeter.
A 9-m (30-ft) gate is located where the access road enters
the site.
The site includes a paved access road to a sludge storage
lagoon and an office/equipment storage building. The building
is prefabricated aluminum on a cement slab, with plumbing and
utility connections. The 3 x 6 m (10 x 20 ft) office area is
insulated and furnished for the attendant and includes rest-
room facilities. The remainder of this structure garages the
cultivation equipment and is closed to the weather on three sides.
The conceptual design includes a lagoon for the interim
storage of sludge. Sludge delivery vehicles discharge into the
lagoon, from which waste is ta'ken by site equipment for subse-
quent cultivation, to keep delivery trucks off unpaved areas
of the site.
The storage lagoon has an installed liner (clay or mem-
brane) and is constructed at the same time as the ditch/berm
and runoff containment pond. Lagoon storage volume ensures
that the orderly cultivation of sludge need not depend on its
time of arrival at the site. Moreover, it is assumed that
inclement weather conditions prevent land cultivation during
approximately 3 months of the year. Thus, the waste storage
facilities should be of sufficient capacity to contain 4 mo
volume of incoming sludge and have an additional foot of free-
board. This capacity not only provides storage for three winter
months, but also allows for a 1-mo-long wet period in the spring,
when cultivation activities are difficult or impossible.
Table 27 shows the cultivation areas and lagoon sizes
required for each of the three assumed amounts of delivered
165
-------
sludge. Site area requirements are determined by dividing the
waste application rate by the waste generation rate; adding the
area required for the access road, perimeter berm, buildings,
waste storage, and runoff control facilities; and adding a 30-m
(100-ft) buffer on all sides.
Figure 26 presents a representative profile of the site,
indicating several of the key features previously discussed.
TABLE 27. CONCEPTUAL DESIGN WASTE AND SITE PARAMETERS
Waste Quantity
(dry t/yr)
Factor 1,000 2,000 4,000
Wet weight (metric tons) volume 20,000 40,000 80,000
(5% solids by weight)
3
Total volume, m 20,000 40,000 80,000
Total volume, 106 gal ' 5.3 10.7 21.4
(267.16 gal/m3)
Land area required (ha)
(0.405 ha/ac/yr):
Waste spreading only 8.8 17.7 35.4
Total (includes roads, 14.2 25.5 46.2
berms, etc.)
Land area required (acres)
(9 ac-in/ac/yr):
For waste spreading only 21.9 43.7 87.4
(36.83 ac-in/106 gal)
Total (including area for 35 63 114
road, building, lagoon,
berms, and 100 to 150 ft
buffer zone)
Storage lagoon volume (sized to
provide sufficient storage for
4 mo/yr):
In m3 6j667 13,333 26,667
In IQo gai It781
WASTE APPLICATION PROCEDURES
The waste to be cultivated is stored and later applied
(spread) on land at an assumed concentration of 5 percent solids
Sludge spreading is accomplished using a pressurized 9.7-m3
(2,600-gal) tank wagon equipped with a power take-off (PTO)
attachment to the same tractor used for subsequent cultivation.
The PTO unit is used to pump sludge from lagoon to tank wagon
166
-------
FENCE
EQUIPMENT STORAGE
BUILDING AND OFFICE
FENCE
WASTE STORAGE
LAGOON (LINED)
LAND CULTIVATION FIELD
RUNOFF
CONTROL
DITCH &
BERM
RUNOFF
CONTROL
DITCH &
BERM
Figure 26. Representative site profile;
-------
via an induced vacuum. The same equipment can be used to remove
standing water from the runoff containment basin during periods
of low spreading activity.
Waste is spread monthly (9/mo/yr) over the entire disposal
area. Each application consists of 1 cm-ha (1 ac-in) of liquid
waste or, in terms of dry weight, 12.5 t/ha (5 tons/ac). When
spreading, the tank wagon and tractor are assumed to cover a
2.4-m (8-ft) strip at an average speed of 0.8 kmph (0.5 mph)
(approximately 5.2 hr/ha or 2.1 hr/ac). Time to refill the 9.7-nr
(2,600-gal) tank wagon, including round-trip travel time to the
storage lagoon, is approximately 10, 12, or 14 min, depending on
the site size.
Waste delivered to the disposal site is sampled (analysis
cost borne by generator), and unloaded into the storage lagoon.
Site personnel record arriving deliveries when they return to
the lagoon for tank wagon refill. An average of 10 min is esti-
mated for recording each delivery. It is assumed that the
smallest site receives an average of five deliveries per day, each
delivery containing an average volume of 15.7 m3 (4,200 gal).
During winter when no cultivation is in progress, the site
will be open and accepting deliveries only 4 hr/day. Thus, only
one part-time employee will be required during the three inactive
winter months, primarily to receive incoming waste deliveries.
This employee may also perform minor site or equipment maintenance
Following waste application, the soil-waste mixture is
allowed to dry for a few days prior to cultivation. One wk or
more may be required for sufficient drying in humid climates or
during the rainy periods in all climates. The soil is then
cultivated to a depth of 20 cm (8 in) by means of a disk unit
3 m (10 ft) wide, pulled by the tractor at an average speed of
10 kmph (6 mph), or approximately 3 ha/hr (7.3 ac/hr). Disking
is performed after each application of waste and at the beginning
and the end of the cultivation season.
The monitoring program requires that samples be taken
quarterly of surface water, groundwater, and soil. These samples
are delivered to a state-certified laboratory for analysis. This
activity is expected to require a maximum of 16 man-hours or
2 man-days each quarter.
Table 28 summarizes labor requirements for each of the
three assumed operation sizes, based on the number of man-hours
of activity which must be completed during the 9-mo cultivation
season.
168
-------
TABLE 28. LABOR REQUIREMENTS FOR CONCEPTUAL LAND CULTIVATION SITE
Waste Quantity
(dry t/yr)
Factor
Spread time (2.4 m width at 0.8 kmph)
(5.2 hr/ha) (hr/yr)
Refill loads/yr (9.7 m3 tank)
Refill time (round trip minutes +
tank fill ) (min)
Refill time (hr/yr)
Disk time (3 m width @ 10 kmph)
(3 ha/hr) (11 diskings/yr) (min)
Winter part-time (4 hr/day)
(3 mo/yr) (hr/yr)
Number of deliveries/day (4,200 gal
or 15.7 m3/delivery) (av)
Non-winter delivery time
(@ 10 min/delivery) (hr)
Sampling time (16 hr/quarter) (hr/yr)
Subtotal hours
Non-productive time (downtime,
breaks, etc. @ 15% of subtotal)
(hr/yr)
Total labor hours/year
Total labor days/year
Total personnel required
The following tabulation s
each site size:
Equipment Type
Tractor, 105 PTO
Tank wagon, 9.7 m3
Disk, 3 tiers, 3 m x 40 cm
1,000
405
2,055
10
342.5
33
260
5
162.5
64
1,267
197
1,464
183
0.7
hows equ
1 ,000
1
1
1
2,000
810
4,110
12
822
66
260
10
325
64
2,347
349
2,696
337
1.3
ipment requi
Waste Quantity
(dry t/yr)
2,000
2
2
1
4,000
1,620
8,220
14
1,918
132
260
20
650
64
4,644
692
5,336
667
2.6
rements for
4,000
3
3
1
ESTIMATED COSTS FOR CONCEPTUAL LAND CULTIVATION SITE
Both capital and operating and maintenance costs
are estimated.
169
-------
Capital Costs
Capital costs associated with land cultivation are presented
in Table 29. The recovery period ("useful life" or "payback"
period) varies according to the type of investment. All capital
costs have been annualized based on a 10 percent interest rate
(or internal rate of return) over their recovery period. Major
capital cost categories are land, site preparation and construc-
tion, public acceptance programs and site closure costs, and
equipment.
The estimated unit cost for land at $8,640/hr ($3,500/ac)
is based on the assumption that the conceptual site is at the
fringe of an industrialized urban center, to assure a market for
its services.
Site preparation and construction cost estimates include
design and survey costs, as well as profit and contingencies
for the contractor. The storage lagoon is lined with a synthe-
tic liner having an estimated 20-yr lifespan and an installed
cost of $4/m2 ($3/yd2). The on-site building was previously
described. Additional space is provided at the larger sites to
accommodate additional equipment. Eighteen meter (60 ft) deep
groundwater monitoring wells are located at each corner of the
site.
The budget for obtaining regulatory agency approval for
land cultivation operations includes the usual costs for state
and local permits and a public education fund to encourage
citizen understanding of the site's needs and goals. Costs for
any litigation or unusually long time delays are not included,
although the possibility of incurring such costs should be
recognized. Litigation costs for establishing sanitary land-
fills may exceed $50,000, with as much as a 2 year delay. Such
landfill site location experience may not be directly applicable
to establishing land cultivation sites, however.
Table 30 describes the procedures and assumptions used
to estimate costs of site preparation and closure. Both the
lagoon and containment basin are assumed to be square in plan.
Earth excavated in constructing the storage lagoon is formed
into a 3 to 1 berm with a 2.4 m (8 ft) wide level top, whereas
the runoff containment basin is a simple 2 to 1 sloped excavation
with the excavated earth used to enhance the ditch/berm around
the perimeter of the disposal site. The containment basin shown
in Figure 27 is assumed to be located on the low corner of the
site. It is 0.3 m (1 ft) wide, with 1 percent sloped runoff
collection ditches emptying into it. Table 31 shows general
dimensions for the storage lagoon and runoff containment basin.
170
-------
TABLE 29. CAPITAL COSTS FOR CONCEPTUAL LAND CULTIVATION SITES*
Cost Element"5"
Urban fringe land @ $8,640/ha:
14, 26 and 46 ha, respectively
Site Preparation:
Grading, berms, storage lagoon
(lined)
Access Road
Fence and gate: 1.5 m within
26 m of perimeter, 4 strand
barbed wire (on top of berm)
Building: office, restroom,
equipment
2
Storage facility (with $32/m
Recovery
Period
I w 1 1 ^JVtfl
(yr)
30
20
20
20
1,000
Total Annual
$122,500 $13,000
72,120 8,470
2,500 120
5,530 650
Waste Quantity
(dry t/yr)
2,000 4
Total
$220,500
90,020
2,500
6,490
Annual Total
$23,390 $399,000
10,020 194,840
120 2,500
760 8,400
,000
Annual
$42,330
22,890
120
990
utilities, $10.8/m2 fixtures
and furniture) 6x 3 m +
6 x 3, 6, 9 m
Monitoring Wells:
4-18 cm wells: 18 m ea @
$26.25/m
Sampling pumps: 4 @ $50 ea
Property Tax and Insurance @
20
20
20
1.5%of In-Place Capital Investments
Budget for Site Approval
20
8,000 940
1,920 230
200 20
3,190
5,000 590
10,000
1,920
200
5,000
U80 12,000
230 1,920
20 200
4,970
590 5,000
1,410
30
20
9,280
590
(continued)
-------
TABLE 29(continued)
Cost Element"1" Recovery
Site Closure Costs @ $2/m3
Cultivation Equipment:
Tractor (105 P.T.O.) 1, 2, and
3 Units
Disk, 3 m x 41 cm, 3 tier
Tank wagon (9.73 m3) l, 2 and
3 units
Stationary Equipment: Lagoon
Aerators
Total Capital Investment
Annual Capital Costs
Annual Capital Costs/Dry t
Period ,
fvr} ''
\y> i
Total
20 $11,020
10 18,000
5 3,500
5 9,500
10 2,000
$261,790
--
Waste Quantity (dry t/yr)
000 2,
Annual Total
$ 1,290 $19,360
2,930 36,000
920 3,500
2,510 19,000
330 2,500
$414,990
$35,190
$ 35.19
000
Annual
$2,280
5,860
920
5,010
410
--
$56,310
$ 28.16
4,
Total
$23,170
54,000
3,500
28,500
3,000
$746,040
--
000
Annual
$3,900
8,790
920
7,520
490
__
$99,460
$ 24.86
* "Total" amounts are initial costs, "annual" amounts are for first 12 months of operation.
All costs are in 1976 dollars.
t Annualized capital recovery (equal annual payments) at 10% interest rate.
-------
TABLE 30. ESTIMATED COSTS FOR SITE PREPARATION
AND CLOSURE*
Item
Lagoon earthwork (m)
Lagoon earthwork cost
@ $7.85/m3
2
Lagoon area (m )
Lagoon liner cost
@ $3.60/m2 installed
Runoff collection ditches
with berm (linear meters)
Collection ditch and berm
@ $9.85/m
o
Runoff containment basin (m )
Containment basin cost
@ $7.85/m3
1,000
1,160
Waste Quantity
(dry t/yr)
2,000
1,650
4,000
$ 840 $ 1,740 $ 2,520
$ 6,560 $- 13,660 $ 19,730
5,350 8,360 12,040
$ 19,200 $ 30,000 $ 43,200
2,480
$ 11,370 $ 16,260 $ 24,360
4,460 7,670 13,710
$ 34,990 $ 60,190 $107,550
Total for lagoon and runoff
containment
$ 72,120 $ 90,020 $194,840
Assumes ditch averages .3 m x .9m
Site closure earthwork" (m) 5,620
Site closure costs
-------
RUNOFF
CONTROL
DITCH
MANUAL
GATES
DIVERSION
DITCH
RUNOFF
CONTAINMENT
BASIN
(SUMP)
RUNOFF CONTROL
DITCH
MANUAL
GATES
DIVERSION
DITCH
Figure 27 . Runoff containment basin
-------
TABLE 3:1. STORAGE LAGOON AND RUNOFF BASIN DIMENSIONS
Waste Quantity
(dry t/yr)
0 Storage lagoon:
Capacity (m3)
Capacity (106 gal)
Length (m)
Length (ft)
Depth* (m)
Depth (ft)
Earthwork (m3)
Earthwork (yd3)
t Runoff containment basin:
Capacity (m3)
Capacity (106 gal)
Length (m)
Length (ft)
Depth* (m)
Depth (ft)
Earthwork (m3)
Earthwork (yd3)
1,000
6,670
1.8
70
238
2.1
7
740
1,090
2,540
0.7
50
170
1.8
6
4,460
5,830
2,000
13,330
3.6 '
90
300
2.7
9
1,540
2,280
4,980
1.3
60
200
2.4
8
7,670
10,030
4,000
26,670
7.1
no
360
3.86
11
2,220
3,290
9,550
2.6
70
240
3
10
13,710
17,920
*Does not include freeboard.
Operation and Maintenance Costs
In addition to capital-related annual costs, annual costs
of site operation include those for labor, fuel and equipment
maintenance, utilities, site maintenance and security, and
monitoring, including sample analyses. Table 32 shows the
basis of estimated labor costs and presents the additional data
for determining operating and total annual costs.
Land cultivation is a land-intensive activity, often
requiring considerable site preparation. Thus, Table 32 shows
that capital costs constitute the largest portion of the total
annual costs for this conceptual design.
175
-------
TABLE 32. ANNUAL CAPITAL AND OPERATION AND MAINTENANCE
COSTS FOR LAND CULTIVATION*
Waste Quantity (dry t/yr)
Cost Element 1,000 2.000 4,000
Operating Costs:
Labor @ $8/hr including fringes $ 11,710 $ 21,570 $ 42,680
Equipment fuel and maintenance
@ $10/man hr to spread, refill,
and disk 7,800 1,700 3,670
Site utilities @ $100, 120, and
150/mo (3 $2.96/ha/mo 500 900 1,630
Site security @ $10, 12, or 14/
night for patrol car drive-by 3,650 4,380 5,110
Sample analysis lab work (32
samples x 10 parameters ea @ $10/
parameter) 3,200 3,200 3,200
Annual Operating Costs
Annual Capital Costs
Subtotal
Administrative Costs (15%)
Contingency Allowance (10%)
Total Annual Costs
Annual Costs/dry t
28,070
35,180
$ 63,250
9,490
6,330
$ 79,060
$ 79.1
33,190
56,310
$ 89,490
13,420
8,950
$111,870
$ 55.9
58,090
99,460
$ 157,550
23,630
15,760
$ 196,940
$ 49.2
* Annual costs are for first 12 months of operations. All costs are
in 1976 dollars.
176
-------
All estimated costs for the conceptual designs are based
on 1976 dollars. It is to be expected that those costs will
rise in the future due to inflation, but no cost projections
were made because of inflation rate uncertainty. For commercial
sites, as presented here, disposal fees are structured to
recover all costs and provide a reasonable profit. Therefore,
cost increases resulting from inflation would be covered by the
site operator through increased disposal fees.
As expected, the total unit costs shown at the bottom of
Table 33 indicate that larger land cultivation sites are less
costly to operate on a unit cost basis than are smaller sites.
This situation is graphically depicted in Figure 28.
177
-------
1000 2000 3000 4000
WASTE QUANTITY - DRY METRIC TONS/YEAR
Figure 28 . Land cultivation annual unit costs.
178
-------
SECTION 14
CASE STUDY SUMMARIES
Five case study sites were investigated in depth to provide
technical and economic information on the disposal of industrial
wastewater, sludge, and municipal refuse by land cultivation.
In addition, less extensive information was obtained from a sixth
site in Michigan.
The objective of each case study is to assemble and inter-
pret available information on:
History of land cultivation at the site
Site characteristics
Waste characteristics and application methods
Costs
Public acceptance problems encountered and
solutions implemented.
Land cultivation sites were identified through contact with
federal, state, and local officials responsible for regulation of
wastewater and solid waste disposal, as well as private contrac-
tors who have been involved in land cultivation activities. Sites
identified were contacted to fill information gaps and to deter-
mine the willingness of site owners/operators to participate in
the project. Descriptions and discussions for each case study
site are presented in Section 3 of Volume 2.
LAND CULTIVATION OPERATIONS
Relatively few land cultivation sites were located where
a regular program of mixing waste and surface soils is practiced.
Many examples of land application systems (e.g., spray irrigation)
were identified. Land application systems other than land culti-
vation were not investigated in this study since these systems
are outside the scope of this contract.
Table 33 shows that the case study sites investigated
represent diverse geographical, climatological, waste, and dis-
posal operation characteristics. Locations of the sites are
given in only very general terms because the operators have
requested anonymity. As Table 33 indicates, land cultivation is
primarily applicable for organic wastes. Depending on variables
such as waste and soil characteristics, these wastes are applied
either to help fertilize and condition the soil or to use the
179
-------
TABLE 33. SUMMARY OF CASE STUDY SITE TECHNICAL INFORMATION
Item
Type of Site
Site Age (yrs)
Disposal area
ha
ac
Climate
Annual ppt.
cm
in
Av. ann. temp.
°c
00 of
o
Topography
(slope)
Soil type
at site
Waste types
Ann. waste
Input
Southern
California
waste disposal
22
12
30
37
15
15
59
mostly <]%
sand
drilling muds and
tank bottoms
j
82,970 irT
Rhode Island
turf farm
3
24
60
109
43
10
51
<1%
silt loam
(glacial
outwash)
secondary sludge
from organic
chemical mfg
3
3,400 mj
Case Study
Indiana
agricultural land
1
20
50
104
42
15
56
<1% to 5%
loamy sand
lime/ferric chlo-
ride/polymer primary
sludge with minor
amounts of acti-
vated sludge from
soap mfg
0
6,490 m
Site
Illinois
waste disposal
4
45
110
84
33
10
51
mostly <1%
clay
several types of in-
dustrial waste, in-
cluding rendering
waste, caustic water,
and stack scrubber
bl owdown
0
37,350 mj
Texas
disposal on
pasture land
3
607
1,500
36
14
18
64
mostly <1%
loam and
sandy loam
shredded municipal
refuse, sewage
sludge, and septic
tank pumpings
17,700 HT
Michigan
tree farm
1
1,200
3,000
79
31
8
48
0-10%
range: sand
to clay
waste activated
sludge from
semi -chemical
pulp and paper
mill
3
94,400 mj
(continued}
-------
TABLE 33 (continued)
CO
Item
Haul distance
km
mi
Application
method
Application
rate
cum/ ha
gal/ac
Application
frequency
Cultivation
frequency
Additional
storage
facilities
Monitoring
waste
groundwater
surface water
vegetation
soils
Soil Amendments
fertilizer
Southern
California
varies
spread with dozer
950-1,500
40,000-63,000
once/3-7 weeks
once/3-7 weeks
none
no
yes
no
no
yes
no
Rhode Island
20
12
spread from tank
truck
228
24,000
once/2 years
once/2 years
none
solids, metals
no
no
no
no
27-6-4
Case Study
Indiana
27
17
subsurface injection
114
12,000
once/year
none*
none
solids, N, If, pll,
Alk, metals
no
yes
yes
yes
no
Site
IlHorils
varies
spread from tank
wagon
- 59
6,250
twice/week
2 times/week
9,840 m3 (2.6 mg)
yes
yes (4 wells)
no
no
no
no
Texas
8+
5+
dumped in windrows
and thin spread
134-278 mt/ha
60-124 5/ac
one application
only
initially and
after 6 months
none
sludge
no
no
in the future
in the future
no
Michigan
32 (maximum)
20 (maximum)
subsurface
injection
190
20,000
once/15 years
none
151 m3
(40,000 gal)
Ca, metals, N,
P, K
on test plots
no
yields
no
no
Deep injection. Cultivate only if odors develop.
-------
soil as a disposal sink. At the Odessa, Texas, and Michigan
sites, the waste was applied to help fertilize and condition the
soil. At the other four sites investigated, low-cost waste
disposal without environmental degradation is the objective.
Waste application rates are determined to a large extent
by the rate of waste decomposition, irrespective of the primary
objective of the six land cultivation operations investigated.
The waste decomposition rate is affected by many factors, expec-
ially waste type, application procedures, and climate. Waste
type is normally the principal factor controlling the decompo-
sition rate. This is because waste nutrient, salt, metal, and/or
water content may limit the total quantity of waste applied and
the rate of application. For example, the high water content of
wastes disposed at the Indiana site interfered with attempts at
land cultivation until a sufficiently large site was acquired
to handle the hydraulic loading.
Application procedures are also important. Waste appli-
cation methods that can maintain aerobic conditions will maxi-
mize the waste decomposition and thereby application rate, since
a change of 10°C (20°F) may affect bacterial metabolism by a
factor as high as 2 (202).
Climate can also place certain constraints on specific
land cultivation operations. For example, periods of heavy
rains occasionally halt operations at the Indiana and Illinois
sites, while freezing conditions prevent waste application
approximately 3 mo each year at the Illinois, Michigan, and
Rhode Island sites.
At the Rhode Island site, waste application is limited by
the use of the site as a turf farm, since wastes are only applied
to bare fields between turf stripping and reseeding. At the
Michigan site, wastes are currently applied only to cleared lots
prior to replanting. Since this results in a lapse between
applications, experiments are in progress to determine the
suitability of the waste for use on young trees.
Thus, land cultivation is controlled somewhat by climatic
conditions and other situations. In addition, both environmental
and practical considerations affect land cultivation. For
operations to be environmentally acceptable, monitoring programs
are being conducted or planned by five of the six case study
sites. Monitoring typically consists of sampling the waste and
soil four times per year. At some sites, surface water, ground-
water, and vegetation are also sampled at regular intervals,
depending on state and local regulatory requirements and on the
apparent potential for contamination.
Practical considerations such as regulatory requirements
and public acceptability were found to be similar for all six
182
-------
sites investigated. None of the six states involved has specific
regulations for land cultivation of municipal refuse. Texas
does have regulations pertaining to land cultivation, but these
are designed to regulate industrial waste and not municipal
refuse applications. Because of the lack of state regulations
specifically written for land cultivation, each site is handled
on a case-by-case basis.
Public acceptability has been good at all six sites. Odors
were initially a problem at the Michigan and Indiana sites, but
use of subsurface injection eliminated this problem. At five of
the six sites, the owners/operators have worked closely with
state regulatory agencies and local residents to facilitate public
acceptance. At two of the sites, tours are periodically conducted
for environmental and school groups.
LAND CULTIVATION ECONOMICS
Table 34 summarizes available information concerning the
economics for the case study sites. Because of differences in
site and waste characteristics, and waste application rates and
methods, the costs vary for each site operation. Moreover,
detailed cost information is often unavailable since it is
generally considered proprietary. Also, the accounting methods
used by site operators sometimes omit or lump together certain
cost factors. Thus, for some sites, cost data is estimated
based on best available information.
Figure 29 presents unit costs in dollars per cubic meter
for the six land cultivation sites plotted against the annual
waste quantity. For comparison purposes, the conceptual design
(Section 13) costs are also plotted. Both the case study and
conceptual design costs indicate that definite economies of
scale are possible when land cultivating wastes.
Operations and costs at the Illinois and Southern Califor-
nia sites are similar to those of the conceptual design. How-
ever, the Michigan, Indiana, and Rhode Island costs include
transportation of sludge to the site, off-site sludge storage,
and pretreatment. Further, no land costs are included for
Michigan and Rhode Island. To provide an equitable comparison,
the Indiana, Michigan, and Rhode Island costs have been adjusted
so that all six case study sites and the conceptual design have
costs calculated on the same basis (Figure 29).
In adjusting costs, transportation costs for the Rhode
Island and Indiana sites were estimated using data supplied by
the California and Rhode Island Public Utilities Commissions
and the Indiana Motor Carriers Tariff Department. This data
indicated that, for the distances involved, a reasonable estimate
was 9<£/km/m3 (0.05$/m1/gal). For those sites where land costs
were not included, the implicit land value was assumed to be
183
-------
TABLE 34. CASE STUDY COST SUMMARY*
00
-pi
Soil Enrichment Sites
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Cost Elements
Amount of waste received per yr
Pretreatment/offsite storage
Annual costs
Unit costs
Transport to site
Annual costs
Unit costs
Onsite storage
Annual costs
Unit costs
Spread ing/ cultivation
Annual costs
Unit costs
Monitoring
Annual costs
Unit costs
Other O&M (not included above)
Annual costs
Unit costs
Land costs (if not included above)
Annual costs
Unit costs
Total costs
Average unit costs
Texas
17,700 MT
73,700
4.16
30,420
1.72
N.A.*
29,620
1.67
N.A.
N.A.
1
0.00
133,741
7.56/HT
Indiana
6,490 m3
N.I.**
See No. 5
See No. 5
Includes Nos. 3&4
in, ooo
17.10
11,000
1.69
N.A.
9,000
1.39
131,000
20.10/m3
Rhode
Island
3,400 m3
4,000
1.18
See No. 5
N.A.
Includes No. 3
13,500
3.97
N.A.
6,630
1.95
0
0.00
24,130
7.10/tn3
Michigan
t
94,400 m3
140,000
1.48
See No. 4
Includes No. 3
73,000
0.77
85,000
0.90
5,500
0.06
26,500
0.28
0
0.00
330,000
3.50/m3
Waste Disposal Sites
Illinois
37,350 m3
N.I.
H.I.
2,000
.05
Includes No. 8
145,906
3.91
N.A.
N.A.
See 5
147,906
3.96/m3
Southern
California
82,970 m3
N.I.
N.I.
N.A.
156,573
1.89
N.I.
N.A.
52,191
0.63
208,764
2.52/m3
^ ' '* "~~ ''' '"' " ' -...». . « MM
All units are as Indicated. Costs due to taxes, insurance, profits, etc., are included where appropriate.
Volume and cost for this mini-case study are for 1975 only. All costs in 1976 collars except where indicated.
Not applicable.
**Not included.
-------
CO
en
ro
12
ffl
INDIANA
RHODE
ISLAND
T
O CASE STUDY, UNADJUSTED COST;
INCLUDES TRANSPORT COST
A CASE STUDY, ADJUSTED COST;
NO PRETREATMENT, OFF-SITE STORAGE,
OR TRANSPORTATION COST (1)
IMPLICIT LAND VALUE INCLUDED (3)
CONCEPTUAL DESIGN COSTS - DO
- NOT INCLUDE TRANSPORT,
PRETREATMENT, OR
OFFSITE STORAGE
JOLIET, ILLINOIS
SOUTHERN
CALIFORNIA,
NOTES:
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
WASTE INPUT - 1000'S OF IT13/YR.
(1) TRANSPORT COST FOR RI AND IN ESTIMATED AT 9 $ km/m3
TRANSPORT COSTS FOR ESTIMATED AS 50% OF CAPITAL COSTS AND 100% OF
O&M AND LABOR COSTS FOR TRANSPORT EQUIPMENT.
(2) UNIT COSTS BASED ON 1976 DOLLARS EXCEPT MI WHICH IS 1975.
(3) LAND ASSUMED TO HAVE A VALUE OF 25% OF ADJUSTED OR 20% OF RE-ADJUSTED UNIT COSTS.
Figure 29. Case study and conceptual design unit costs of liquid waste cultivation.(2)
-------
25 percent of adjusted total annual cost for that site. This
percentage was based on the results of the conceptual design
economic analysis reported in Section 13.
186
-------
REFERENCES
1. U.S. House of Representatives. Material Relating to the
Resource Conservation and Recovery Act of 1976. U.S.
Government Printing Office, Washington, D.C., 1976. 86 p.
2. Baum, B. and C. H. Parker. Solid Waste Disposal. Vol. 1:
Incineration and Landfill. Ann Arbor Sci. Publ. Inc.,
Ann Arbor, Michigan, 1974. 397 p.
3. Volk, V. V. and C. H. Ullery. Disposal of Municipal Wastes
on Sandy Soils. Report to the Boeing Company, Department
of Soil Science, Oregon State University, Corvallis, 1972.
4. Durlak, E. R. Solid Waste Disposal by Landspreading Tech-
niques, TN No. N-1491. Naval Construction Battalion Center,
Port Hueneme, California. February, 1977.
5. Stanford, 6. B. The Houston Landmix Trial. Agronomy
Abstracts. Annual Meetings, Amer. Soc. Agron., Houston,
Texas, 1976. p. 34.
6. Council on Environmental Quality. First Annual Environ-
mental Quality Report. U.S. Government Printing Office,
Washington, D.C., 1970.
7. Hortenstine, C. C. and D. F. Rothwell. Pelletized
Municipal Refuse Compost as a Soil Amendment and Nutrient
Source for Sorghum. J. Environ. Qual., 2:343-345, 1973.
8. Winkler, P. E. and D. G. Wilson. Size Characteristics of
Municipal Solid Waste. Compost Science, 14(5):6-11, 1973.
9. California State Solid Waste Management Board. Resource
Recovery Program, Vol. II. 1976.
10. U.S. Environmental Protection Agency. Third Report to
Congress: Resource Recovery and Waste Reduction. Solid
Waste Management Series, Publication No. SW-161, 1975.'
p. 10.
11. Hart, S. A., W. J. Flocker, and G. K. York Refuse Stabil-
ization in the Land. Compost Science, ll(l):4-8, 1969.
187
-------
REFERENCES (continued)
12. Volk, V. V. Application of Trash and Garbage to Agricul-
tural Lands. In: Land Application of Waste Materials,
Soil Conservation Society of America, Ankeny, Iowa, 1976.
pp. 154-164.
13. Cottrell, N. M. Disposal of Municipal Wastes on Sandy
Soil: Effect on Plant Nutrient Uptake. M.S. Thesis,
Oregon State University, Corvallis, 1975.
14. Halverson, G. A. Movement of Elemental Constituents in
Sagehill Loamy Sand Treated with Municipal Waste. M.S.
Thesis, Oregon State University, Corvallis, 1975.
15. King, L. D., L. A. Rudgers, and L. R. Webber. Application
of Municipal Refuse and Liquid Sewage Sludge to Agricultural
Land: I. Field Study. J. Environ. Qual. , 3:361-366, 1974.
16. Page, A. L. Fate and Effects of Trace Elements in Sewage
Sludge when Applied to Agricultural Lands. EPA-670/2-74-
005, U.S. Environmental Protection Agency, January 1974.
17. Hortenstine, C. C. and D. F. Rothwell. Use of Municipal
Compost in Reclamation of Phosphate Mining and Tailings.
J. Environ. Qual., 1:415-418, 1972.
18. Bengtson, G. W. and J. J. Cornette. Disposal of Composted
Municipal Waste in a Plantation of Young Slash Pine:
Effects on Soil and Trees. J. Environ. Qua!., 2:441-444,
1973.
19. Scanlon, D. H., C. Duggans, and S. D. Bean. Evaluation of
Municipal Compost for Strip Mine Reclamation. Compost
Sci. , 14(3):4-8, 1973.
20. Duggan, J. C. and D. H. Scanlon. Evaluation of Municipal
Refuse Compost for Ash Pond Stabilization. Compost Sci.,
15(1):26-30, 1974.
21. Terman, G. L., J. M. Soileau, and S. E. Allen. Municipal
Waste Compost: Effects on Crop Yields and Nutrient Content
in Greenhouse Pot Experiment. J. Environmental Qual.,
2:84-89, 1973.
22. Wallace, A. T. Land Disposal of Liquid Industrial Wastes.
In: Land Treatment and Disposal of Municipal and Industrial
Wastewater. R. L. Sanks and T. Asan.o, eds. Ann Arbor
Science Publishers, Ann Arbor, Michigan, 1976. pp. 147-162.
188
-------
REFERENCES (continued)
23. Pound, C. E. and R. VI. Crites. Wastewater Treatment and
Reuse by Land Application. Vol. I-II. EPA-660/2-73-006a
August 1973.
24. Reed, S. C. Land Disposal - State of the Art. In:
National Symposium on Ultimate Disposal of Wastewaters and
Their Residuals, Durham, North Carolina, April 26-27, 1973.
pp. 229-261.
25. Hunt, P. G., L. C. Glide, and N. R. Francingues. Land
Treatment and Disposal of Food Processing Wastes. In:
Land Application of Waste Materials, Soil Conservation
Society of America, Ankeny, Iowa, 1976. pp. 112-135.
26. Dotson, G. K., et al. Land Spreading, a Conserving and
Nonpolluting Method of Disposing of Oily Wastes. Presented
at 5th International Water Pollution Res. Conference and
Exhibition, San Francisco, California July 26-August 1,
1970.
27. Kincannon, C. B. Oily Waste Disposal by Soil Cultivation
Process. EPA-R2-72-100, U.S. Environmental Protection
Agency, December 1972.
28. Lewis, R. S. Sludge Farming of Refinery Wastes as Practiced
at Exxon's Bayway Refinery and Chemical Plant. Presented
at the National Conference on Disposal of Residues on Land,
St. Louis, Missouri, September 13-15, 1976.
29. California State Department of Public Health. Tentative
Guidelines for Hazardous Waste Land Disposal Facilities.
Supplement Hazardous Waste Disposal Survey - 1971.
30. American Paper Institute. 1975-1978 Capacity: Paper,
Paperboard and Wood Pulp Fiber Consumption, with Addit-ional
data for 1979-1981.
31. American Wood Preservers' Association. Wood Preservation
Statistics for 1975. Washington, D.C., September 1976.-
32. Brown, G. E. Land Application of High Nitrogenous Indus-
trial Wastewater. In: Proceedings of the National
Conference on Management and Disposal of Residues from the
Treatment of Industrial Wastewaters, 1976, Washington, D.C.
pp. 247-252.
33. Middlebrooks, E. J. Wastes from the Preservation of Wood.
Journal of the Sanitary Engineering Division ASCE, 94 (SAI):
41-54, February 1968.
189
-------
REFERENCES (continued)
34. SCS Engineers. Assessment of Industrial Hazardous Waste
Practices - Leather Tanning and Finishing Industry.
Contract No. 68-01-3261, U.S. Environmental Protection
Agency, November 1976.
35. U.S. Bureau of the Census. 1972 Census of Manufacturers.
Special Repo1-**. Aeries: Water Use in Manufacturing Series
MC 72 (SR)-4. U.S. Government Printing Office, Washington,
D.C., 1975.
36. U.S. Department of Commerce, U.S. Industrial 1976 Outlook.
U.S. Government Printing Office, Washington, D.C., 1976.
37. U.S. Environmental Protection Agency. Development Document
for Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Major Organic Products Segment of
the Organic Chemicals Manufacturing Point Source Category.
EPA 440/1-73-009, December 1973.
38. U.S. Environmental Protection Agency. Development Document
for Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Plywood, Hardboard and Wood Pre-
serving Segment of the Timber Products Processing Point
Source Category. EPA 440/1-74-023a, April 1974.
39. U.S. Environmental Protection Agency. Development Document
for Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Textile Mills Point Source Category.
EPA 440/1-74-022a, June 1974.
40. U.S. Environmental Protection Agency. Development Document
for Effluent Limitations Guidelines and New Source Perform-
ance Standards for the Unbleached Kraft and Semi-chemical
Pulp Segment of the Pulp, Paper and Paperboard Mills Point
Source Category, EPA 440/1-74-025a, May 1974.
41. Versar, Inc. Assessment of Industrial Hazardous Waste
Practices - Textiles Industry, Contract No. 68-01-3178,
U.S. Environmental Protection Agency, June 1976.
42. Jacobs Engineering. Assessment of Industrial Hazardous
Waste Practices - Petroleum Refining Industry, Contract No.
68-01-2288, U.S. Environmental Protection Agency.
43. SCS Engineers. Unpublished data. 1975.
190
-------
REFERENCES (continued)
44. Subcommittee on Transportation and Commerce of the House
Committee on Interstate and Foreign Commerce. Materials
Relating to the Resource Conservation and Recovery Act of
1976. U.S. Government Printing Office, 1976.
45. Alexander, M. Introduction to Soil Microbiology. 2nd ed.
John Wiley and Sons, Inc., New York, New York, 1977.
46. Martin, J. P., and D. D. Focht. Biological Properties of
Soils. In: Soils for Management of Organic Wastes and
Waste Waters. American Society of Agronomy, Madison,
Wisconsin, 1977. pp. 115-169.
47. Phillips, C. R., and J. Nathwani. Soil-Waste Interactions:
A State-of-the-Art Review. Solid Waste Management Report
EPS 3-EC-76-14. Environmental Canada, 1976.
48. Broadbent, F. E. Organics. In: Proc. of the Joint
Conference on Recycling Municipal Sludges and Effluents on
Land, Champaign, Illinois, July 9-13, 1973. pp. 97-101.
49. Meiklejohn, J. Some Aspects of the Physiology of Nitrifying
Bacteria. In: Autotrophic Microorganisms, B. A. Fry and
J. L. Peel, eds. Cambridge Univ. Press, London, 1954.
pp. 68-83.
50. Alexander, M. Biodegradation: Problems of Molecular-
recalcitrance and Microbial Fallibility. Adv. Applied
Microbiol ., 7:35-80, 1965.
51. Miller, R. H. The Soil as a Biological Filter. In:
Proceedings on Conference on Recycling Treated Municipal
Wastewater through Forest and Cropland. EPA-660/2-74-003.
U.S. Environmental Protection Agency, 1974.
52. Stewart B. A. and L. R. Webber. Consideration of Soils for
Accepting Wastes. In: Land Application of Waste Materials.
Soil Conservation Society of America, Akeny, Iowa, 1976.
pp. 8-21.
53. Mahendrappa, M. K., et al. Nitrifying Organisms Affected
by Climate Regions in Western United States. Soil Sci.
Soc. Amer. Proc., 30:60-62, 1966.
191
-------
REFERENCES (continued)
54
55
56
57
58.
59
60
61
62,
63,
Webber, L. R. and E. G. Beauchamp. Land Utilization and
Disposal of Organic Wastes in Cool Subhumid and Humid
Regions. In: Soils for Management of Organic Wastes and
Waste Waters, L. F. Elliott and F. J. Stevenson, eds.
American Society of Agronomy, Madison, Wisconsin, 1977.
pp. 456-470.
Phung, H. T. Reduction Processes in Modified Spodosal
Systems and Their Effects on Some Plant Responses. Ph.D.
Dissertation, University of Florida, 1972. (Dis. Abstr.
Int., 34:No. 6, 2405B).
Leithe, W. The Analysis of Organic Pollutants in Water and
Waste Water. Ann Arbor Science Publishers, Inc., Ann
Arbor, Michigan, 1973.
Kaufman, D. D., and R. D. Doyle. Biodegradation of
Organics. In: 1977 National Conference on Composting of
Municipal Residues and Sludges. Information Transfer, Inc.,
Rockville, Maryland, 1978. pp. 75-80.
Kaufman, D.
organisms.
Guzeni, ed.
1974. pp.
D. Degradation
In: Pesticides
Soil Sci. Soc.
133-202.
of Pesticides by Soil
in Soil and Water, W.
Amer. , Inc. , Madison,
Micro-
D.
Wisconsin,
Martin, J. P. and A. L. Page. Capacity of Soils for
Hazardous Organic Substances. In: 1977 National Confer-
ence on Comp of Municipal Residues and Sludges. Informa-
tion Transfer, Inc., Rockville, Maryland, 1978. pp. 101-
105.
Kearney, P. C., et alI. Persistence of Pesticide Residues
in Soils. In: Chemical Fallout: Current Research on
Persistent Pesticides, M. W. Miller and G. G. Berg, eds.
Charles C. Thomas, Springfield, Illinois.
Armstrong, D. E., and J. G. Konrad. Nonbiological Degrada-
tion of Pesticides. In: Pesticides in Soil and Water,
W. D. Guzeni, ed. Soil Sci. Soc. Amer., Inc., Madison,
Wisconsin, 1974. pp. 123-131.
Konrad, J. G. et al. Soil Degradation of Diazinon, a
Phosphorothioate Insecticide. Agron. J., 59:591-594,
1967
Harris, C. I. Fate of Two-s^-Triazine
J. Agr. Food Chem., 15:157-162, 1967.
Herbicides in Soil
192
-------
REFERENCES (continued)
64. Getzin, L. W. Persistence of Diazinon and Zinophos in
Soil: Effects of Autoclaving, Temperature, Moisture, and
Acidity. J. Econ. Entomol., 61:1560-1565, 1968.
65. Rosen, J. D. Photodecomposition of Organic Pesticides. In:
Organic Compounds in Aquatic Environments, S. J. Faust and
J. V. Hunter, eds. Marcel Dekker, Inc., New York, 1971.
pp. 425-438.
66. Hatayama, H. K., and D. Jenkins. An Evaluation of the
Weathering Method of Disposal of Leaded Gasoline Storage
Tank Wastes: A Summary. In: Proceedings of the National
Conference about Hazardous Waste Management (San Francisco,
February 1-4, 1977); In Press.
67. Ruzo, L. 0., et al. Photodegradation of Polybromobiphenyls
(PBB). J. Agric. Food Chem. , 24:1062-1065, 1976.
68. Spencer, W. F., and M. M. Cliath. Vaporization of
Chemicals. In: Environmental Dynamics of Pesticides,
R. Haque and V. H. Freed, eds. Plenum Publishing Co.,
New York, New York, 1975. pp. 61-78.
69. Spencer, W. F., et al. Vapor Density of Soil-Applied
Dieldrin as Related to Soil-Water Content, Temperature and
Dieldrin Concentration. Soil Sci. Soc. Amer. Proc.
33:509-511 , 1969.
70. Willis, 6. H., et al . Volatilization of Dieldrin from
Fallow Soil as Affected by Different Water Regimes. J.
Environ. Qua!., 1:193-196, 1972.
71. Farmer, W. J., et al. Problems Associated with the Land
Disposal of an Organic Industrial Hazardous Waste Contain-
ing HCB. In: Proceedings of the Hazardous Waste Research
Symposium on Residual Management and Land Disposal. EPA-
600/9-76-015, U.S. Environmental Protection Agency, 1976.
pp. 177-185.
72. Hortenstine, C. C. and D. R. Rothwell. Evaluation of Com-
posted Municipal Refuse as a Plant Nutrient Source and Soil
Amendment on Leon Fine Sand. Proc. Soil and Crop. Sci.
Soc. Fla., 29:312-319, 1969.
73. Mays, D. A., G. L. Terman, and J. C. Duggan. Municipal
Compost: Effects on Crop Yields and Soil Properties.
J. Environ. Qua!., 2:89-92, 1973.
193
-------
REFERENCES (continued)
74. Duggan, J. C. Utilization of Municipal Refuse Compost, I.
Field Scale Compost Demonstrations. Compost Sci . , 14 (2):
24-25, 1973.
75. Epstein, E. Effect of Sewage Sludge on Some Soil Physical
Properties. J. Environ. Qua!., 4:139-142, 1975.
76. Epstein, E., J. M. Taylor, and R. L. Chaney. Effects of
Sewage Sludge and Sludge Compost Applied to Soil on Some
Soil Physical and Chemical Properties. J. Environ. Qua!.,
5:422-426, 1976.
77. Tisdale, S. L. and W. L. Nelson. Soil Fertility and
Fertilizers. Macmillan Company, New York, 1966.
78. Rothwell, D. F. and C. C. Hortenstine. Composted Municipal
Refuse: Its Effects on Carbon Dioxide, Nitrate Fungi, and
Bacteria in Arrendondo Fine Sand. Agron. J., 61:837-840,
1969.
79. Poison, R. L. Refractory Metals Processing Waste Utiliza-
tion on Dayton Stlty Clay Loam Soil. M.S. Thesis, Oregon
State University, Corvallis, 1976.
80. Udo, E. J. and A. A. A. Fayemi. The Effect of Oil Pollution
of Soil on Germination, Growth and Nutrient Uptakes of Corn.
J. Environ. Qua!., 4:537-540, 1975.
81. Plice, M. J. Some Effects of Crude Petroleum on Soil
Fertility. Soil Sci. Soc. Amer. Proc., 13:413-316, 1948.
82. Adams, R. S. and R. Ellis. Some Physical and Chemical
Changes in the Soil Brought about by Saturation with
Natural Gas. Soil Sci. Soc. of American Proc., 24:41-44,
1960.
83. Hunt, P. G., C. C. Hortenstine, and G. C. Smart. Response
of Plant Parasitic and Saprophytic Nematode Populations to
Composted Municipal Refuse. J. Environmental Qual. ,
2:264-266, 1973.
84. Dobson, A. L. and H. A. Wilson. Refuse Decomposition in
Strip Mine Spoils. Proc. West Virginia Acad. Sci., 35:59-
65, 1973.
85. Ellis R. J. and R. S. Adamas, Jr. Contamination of Soils
by Petroleum Hydrocarbons. Adv. Agron., 13:197-216, 1961.
194
-------
REFERENCES (continued)
86. Odu, C. T. I. Microbiology of Soils Contaminated with
Petroleum Hydrocarbons. I. Extent of Contamination and
Some Soil and Microbiological Properties after Contamina-
tion. J. Inst. Pet., 58:201-208, 1972.
87. Raymond, R. L., J. 0. Hudson, and V. M. Jamison. Oil
Degradation in Soil. Apl. Environ. Microbiol., 31:522-535,
I «/ / D
88. Parr, J. F. Effects of Pesticides on Microorganisms in
Soil and Water. In: Pesticides in Soil and Water, W. D.
Guenzi (ed). Soil Sci. Soc. America, Inc., Madison,
Wisconsin, 1974. pp. 315-340.
89. Steigerwald, E. and U. Springer. Further Experiments with
Refuse, Refuse Compost, and Composts of Refuse and Sludge.
In: International Group on Refuse Disposal 1958-1961.
U.S. Dept. of Health, Education and Welfare, Public Service
Information Bulletin No. 1, 19-22, 1953.
90. Tientjen, C. and S. A. Hart. Compost for Agricultural Land.
J. Sanitary Engineering Division, A.S.C.E., 94:269-287,
1968.
91. Terman, G. I., J. M. Soileau, and S. E. Allen. Utilization
of Municipal Solid Waste Compost: Research Results at
Muscle Shoals, Alabama. Compost Science, 14(1):18-21,
1973.
92. Purves, D. and E. J. Mackenzie. Phytotoxicity Due to Boron
in Municipal Compost. Plant Soil, 40:231-235, 1974.
*
93. Baker, J. M. The Effects of Oils on Plants. Environ.
Pollut., 1:27-44, 1970.
94. Cowell, E. B. The Effects of Oil Pollution on Salt Marsh
Communities in Pembrokeshire and Cornwall. J. Appl . Ecol.,
6:133-142, 1969.
95. Baker, J. M. The Effects of Oil Pollution on Salt Marsh
Communities. In: Field Studies Council Oil Pollution
Research Unit, Annual Report for 1968, Section B, pp. 1-10.
96 Ginsberg, J. M. Penetration of Petroleum Oils into Plant
Tissues. J. Agr. Res., 43:459-474, 1931.
97 Currier, H. B. and S. A. Peoples. Phytotoxicity of Hydro-
carbons, Hilgardia, 23:155-173, 1954.
195
-------
REFERENCES (continued)
98. Baker, J. M. Seasonal Effects. In: The Ecological
Effects of Oil Pollution on Littoral Communities, E. B.
Cowell , ed. The Institute of Petroleum, London, 1971.
pp. 44-51.
99. Carr, R. H. Vegetative Growth in Soils Containing Crude
Petroleum. Soil Sci., 8:67-68, 1919.
100. Murphy, H. G. Some Effects of Crude Petroleum on Nitrate
Production, Seed Germination and Growth. Soil Sci.,
27:117-120, 1929.
101. Giddens, J. Spent Motor Oil Effects on Soil and Crops.
J. Environmental Qual. , 5:179-181, 1976.
102. DeRoo, H. C. Agricultural and Horticultural Utilization
of Fermentation Residues. Conn. Agr. Expt. Sta., Bulletin
750, 1975.
103. Noodharmcho, A. and W. J. Flocker. Marginal Land as an
Acceptor for Cannery Waste. J. Amer. Soc. Hort. Sci.,
100:682-684, 1975.
104. SCS Engineers. Feasibility of Inland Disposal of Dredged
Material: A Literature Review. Environmental Effects
Laboratory, U.S. Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi, 1977.
105. Hughes, G. M., R. A. Landon, and R. N. Farvalden. Hydro-
geology of Solid Waste Disposal Sites in Northeastern
Illinois, Report No. SW-12d. U.S. Environmental Protec-
tion Agency, 1971.
106. LeGrand, H. E. System for Evaluation of Contamination
Potential of Some Waste Disposal Sites. TAWWA, 56:959-974,
1964.
107. Soil Conservation Service, U.S.D.A. Guide for Rating
Limitations of Soils for Disposal of Wastes. Interim
Guide, Advisory Soils - 14. Washington, D.C., 1973.
108. Parizek, R. R. Conference on Recycling Treated Municipal
Wastewater Through Forest and Cropland, EPA-660/2-74-003.
U.S. Environmental Protection Agency, 1974.
109. Viets, F. G., Jr., and R. H. Hageman. Factors Affecting
the Accumulation of Nitrate in Soil, Water, and Plants.
USDA Agri. Handb. No. 413, U.S. Government Printing Office,
Washington, D.C., 1971.
196
-------
REFERENCES (continued)
110. U.S. Environmental Protection Agency. Hazardous Waste
Landfill Site Screening Criteria. Guidance Document,
Preliminary Draft. Office of Solid Waste Management
Programs, 1976.
111. Thomas, R. E., and C. C. Harlen, Jr. Experiences with
Land Spreading of Municipal Effluents. Presented at the
First Annual IFAS Workshop on Land Renovation of Waste-
water, Tampa, Florida, June 1972.
112. Jobson, A., et al. Effect of Amendments on the Microbial
Utilization of Oil Applied to Soil. Applied Microbiology,
27:166-171, 1974.
113. LeGrand, H. E. Movement of Agricultural Pollutants with
Ground Water. In: Iowa State University Press, Ames,
Iowa. T. L. Willrich and G. E. Smith, ed., 1970.
pp. 303-313.
114. Amemiya, M. Land and Water Management for Minimizing
Sediment. T- L. Willrich and G. E. Smith, ed. In:
Agricultural Practices and Water Quality, Iowa State
University Press, Ames, 1970. pp. 35-45.
115. Holmes, J. W., S. A. Taylor, and S. J. Richards. Measure-
ment of Soil Water. Agronomy, 11:295, 1967.
116. Swanson, N. P., J. C. Lorimor, and L. N. Mielke. Broad
Basin Terraces for Sloping Cattle Feedlot . Trans. ASAE,
16:746-749, 1973.
117. Cook, D. I., and D. F. Van Haverbeke. Trees and Shrubs
for Noise Abatement. Res. Bull. 246. Nebr. Agric. Exp.
Stn., Lincoln, Nebraska. 1974.
118. Ham, H. H. Use of Drainage Wells. Pap. No. 74-2518.
Am. Soc. Agri. Eng., St. Joseph, Michigan. 1974.
119. McCalla, T. M., and T. J. Army. Stubble Mulch Farming.
Adv. Agron., 13:125-196, 1961.
120. National Plant Food Institute. The Fertilizer Handbook.
Washington, D.C., 1963.
121. Soil Conservation Service. Maintaining Subsurface Drains.
Leafl. No. 557. U.S. Dept. of Agric. 1971.
197
-------
REFERENCES (continued)
122. Jacobson, P. Mechanics of Water Erosion. In: Agricul-
tural Engineers Handbook. McGraw-Hill, New York, 1961.
pp. 401-413.
123. Smith, D. D., and W. H. Wischmeier. Rainfall Erosion.
Adv. Agron., 14:109-148, 1962.
124. Norstadt, F. A., N. P. Swanson, and B. A. Sabey. Site
Design and Management for Utilization and Disposal of
Organic Wastes. In: Soils for Management of Organic
Wastes and Waste Waters, L. F. Elliott and F. J. Stevenson,
ed., Am. Soc. Agron., Madison, Wisconsin, 1971. pp. 348-
376.
125. Woodruff, N. P., R. A. Read, and W. S. Chepil. Influence
of a Field Windbreak on Summer Wind Movement and Air
Temperature. Tech. Bull. 100, Kans, Agri. Exp. Stn. 1959,
Manhattan, Kansas.
126. Martinelli, M., Jr. Snow Fences for Influencing Snow
Accumulation. In: Symp. on Measurement and Forecasting
Procedures, Banff, Alberta, Canada. September 1972.
Vol. 2, pp. 1394-1398.
127. Price, W. I. J. The Effects of Characteristics of Snow
Fences on the Quantity and Shape of Deposited Snow. In:
IASH Publ. 54. Int. Assoc. of Sci. Hydrol. General
Assembly Helsinki, 1961. pp. 89-98.
128. Pugh, H. Snow Fences. Road Res. Tech. Pap. No. 19.
Dept. of Sci and Ind. Res., Road Res. Lab. London, 1950.
129. Fuller, W. H. Movement of Selected Metals, Asbestos, and
Cyanide in Soil: Applications to Waste Disposal Problems.
EPA-600/2-77-020 and Addendum, U.S. Environmental Protec-
tion Agency, April 1977.
130. Keeney, D. R. and R. E. Hildung. Chemical Properties of
Soils. In: Soils for Management of Organic Wastes and
Waste Waters. American Society of Agronomy, Madison,
Wisconsin, 1977. pp. 75-97.
131. Miller, R. H. Soil Microbiological Aspects of Recycling
Sewage Sludges and Waste Effluents. In: Proc. of the
Joint Conference on Recycling Municipal Sludges and
Effluents on Land, Champaign, Illinois, July 9-13, 1973.
pp. 79-90.
198
-------
REFERENCES (continued)
132. Rogers, R. D. Methylation of Mercury in Agricultural
Soils. J. Environ. Qua!., 5:454-457, 1976.
133. Alexander, M. Microorganisms and Chemical Pollution.
Bio Science, 23:509-515, 1973.
134. Lindsay, W. L. Inorganic Reactions of Sewage Wastes with
Soils. In: Proc. of the Joint Conference on Recycling
Municipal Sludges and Effluents on Land, Champaign,
Illinois, July 9-13, 1973. pp. 91-96.
135. Doran, J. W., J. R. Ellis, and T. M. McCalla. Microbial
Concerns when Wastes are Applied to Land. In: Land as a
Waste Management Alternative. R. C. Loehr, ed. Proc. of
the 1976 Cornell Agr. Waste Management Conference. Ann
Arbor Sci. Publishers, Inc., Ann Arbor, Michigan, 1977.
pp. 343-261.
136. Lai, S. H. and J. J. Jurinak. The Transport of Cations in
Soil Columns at Different Pore Velocities. Soil Sci. Soc.
Amer. Proc., 36:730-733, 1972.
137. Adriano, D. C., et al. Effect of Long-Term Land Disposal
by Spray Irrigation of Food Processing Wastes on Some
Chemical Properties of the Soil and Subsurface Water.
J. Environ. Qua!., 4:242-248, 1975.
138. U.S. Environmental Protection Agency. Report to the
Congress on Waste Disposal Practices and Their Effects on
Ground Water. January 1977.
139. LaFleur, K. S. Movement of Carbryl through Congaree Soil
into Ground Water. J. Environ. Qual. , 5:91-110, 1976.
140. BitteH, J. E. and J. Miller. Lead, Cadmium, and Calcium
Selectivity Coefficients on a Montmorillonite, Illite, and
Kaolinite. J. Environ. Qua!., 3:250-253, 1974.
141. Singh, B. R. and Y. Kanehiro. Adsorption of Nitrate in
Amorphous and Kaolinitic Hawaiian Soils. Soil Sci. Soc.
Amer. Proc., 33:601-683, 1969.
142. Janne, E. A. Controls on Mn, Fe, Co, Ni, Cu, and Zn
Concentrations in Soils and Water: The Significant Role
of Hydrous Mn and Fe Oxides. In: Trace Inorganics in
Water. Adv. Chem. Ser., 73:337-387. Amer. Chem. Soc.,
Washington, D.C., 1968.
199
-------
cro-
REFERENCES (continued)
143. Hodgson, J. F. Chemistry of Micronutrient Elements in
Soils. Adv. Agron., 15:119-159, 1963.
144. Alesii, B. A. and W. H. Fuller. The Mobility of Three
Cyanide Forms in Soils. In: Proc. of the Hazardous
Waste Research Symp.: Residue Management by Land Disposal.
EPA-600/9-76-015, U.S. Environmental Protection Agency,
July 1976. pp. 213-223.
145. Griffin, R. A. and N. F. Shimp. Leachate Migration through
Selected Clays. In: Gas and Leachate from Landfills.
EPA-600/9-76-004, U.S. Environmental Protection Agency,
March 1976. pp. 92-95.
146. Stevenson, F. J. and M. S. Ardakani. Organic Matter
Reactions Involving Micronutrients in Soils. In: Mi_._
nutrients in Agriculture, J. J. Mortvedt, et al. eds.,
Soil Science Society of America, Madison, Wisconsin, 1972,
pp. 79-114.
147. Ponnamperuma, F. N. The Chemistry of Submerged Soils.
Adv. Agron., 24:29-96, 1972.
148. Phung, H. T. and J. G. A. Fiskell. A Review of Redox
Reactions in Soils. Proc. Soil and Crop Sci. Soc.,
Florida, 32:141-145, 1972.
149. Martell, A. E. Principles of Complex Formation. In:
Organic Compounds in Aquatic Environments. S. D. Vanst
and J. V. Hunter, eds. Marcel Dekker, Inc., New York,
1971. pp. 239-263.
150. Fuller, W. H. and N. Korte. Attenuation Mechanisms of
Pollutants through Soils. In: Gas and Leachate from
Landfills. EPA-600/9-76-004, U.S. Environmental Protec-
tion Agency, March 1976. pp. 111-122.
151. Griffin, R. A., et al. Attenuation of Pollutants in
Municipal Landfill Leachate by Clay Minerals: I. Column
Leaching and Field Investigation. Environ. Geol. Notes,
No. 78, November 1976.
152. Jennett, J. C. and S. M. Linnemann. Disposal of Lead and
Zinc Containing Wastes on Soils. Journal WPCF, 49:1842-
1856, 1977.
153. Helling, C. S. Pesticide Mobility in Soils, II. Applica-
tion of Soil Thin-Layer Chromatography. Soil Sci. Soc.
Amer. Proc., 35:737-743, 1971.
200
-------
REFERENCES (continued)
154. Filonow, A. B., L. W. Jacobs, and M. M. Mortland. Fate of
Polybrominated Biphenyls (PBB's) in Soils. Retention of
Hexabromobiphenyl in Four Michigan Soils. J. Agri. Food
Chem., 24:1201-1204. 1976.
155. Burnside, 0. C., C. R. Fenster, and G. A. Wicks. Dissipa-
tion and Leaching of Monuron, Simazine, and Atrazine in
Nebraska Soils. Weeds, 11:209-213, 1963.
156. Wiese, A. F. and R. G. Davis. Herbicide Movement in Soil
with Various Amounts of Water. Weeds, 12:101-103, 1964.
157. Bovey, R. W., et al. Occurrence of 2,4,5-T and Picloram
in Surface Runoff Waters in the Blacklands of Texas. J.
Environ. Qual., 3:61-64, 197.4.
158. LaFleur, K. S., W. R. McCaskill, and D. S. Adams. Movement
of Prometryne through Congaree Soil into Ground Water.
J. Environ. Qua!., 4:132-133, 1975.
159. Barnett, A. P., et al. Loss of 2,4-D in Washoff from
Cultivated Land. Weeds, 15:133-137, 1975.
160. White, A. W., et al. Atrazine Losses from Fallow Land
Caused by Trifluration Volatilization Losses, Runoff and
Erosion. Environ. Sci . Tech., 1:740-744, 1967.
161. U.S. Environmental Protection Agency. Quality Criteria for
Water. EPA-440/9-76-023, July 1976.
162. Mosier, A. R., et al. Odors and Emissions from Organic
Wastes. In: Soils for Management of Organic Wastes and
Waste Waters. American Society of Agronomy, Madison,
Wisconsin, 1977. pp. 531-571.
163. Miner, J. R. Odors from Livestock Production. Amer. Eng.
Dept., Oregon State University, Corvallis, 1973.
164. Tarquin, A. J. and J. Dowdy. Low Pressure Spray Irrigation
of Meatpacking Plant Wastewater (Summary). Paper No.
75-2016, Amer. Soc. Agr. Eng., St. Joseph, Michigan, 1975.
165. Allaway, W. H. Agronomic Control over Environmental
Cycling of Trace Elements. Advan. Agron., 20:235-274,
1968.
201
-------
REFERENCES (continued)
166. Allaway, W. H. Food Chain Aspects of the Use of Organic
Residues. In: Soils for Management of Organic Wastes and
Waste Waters. American Society of Agronomy, Madison,
Wisconsin, 1977. pp. 283-298.
167. Chaney, R. L. and P. M. Giordano. Micronutrients as
Related to Plant Deficiencies and Toxicities. In: Soils
for Management of Organic Wastes and Waste Waters. Amer.
Soc. of Agron., Madison, Wisconsin, 1977. pp. 235-279.
168. Underwood, E. J. Trace Elements in Human and Animal
Nutrition. 3rd ed. Academic Press, New York, 1971.
169. Walsh, L. M., M. E. Sumner, and R. B. Corney. Considera-
tion of Soils for Accepting Plant Nutrients and Potentially
Toxic Nonessential Elements. In: Land Application of
Waste Material. Soil Conservation Society of America,
Ankeny, Iowa, 1976. pp. 22-47.
170. Friberg, L. T., et al. Cadmium in the Environment. 2nd
Edition. Chemical Rubber Company. Cleveland, Ohio, 1974.
171. Pahren, H. R., et al. An Appraisal fo the Relative Health
Risks Associated with Land Application of Municipal Sludge.
Presented at the 50th Annual Conference of the Water
Pollution Control Federation, Philadelphia, Pennsylvania,
October 2-6, 1977.
172. Task Force Members. Application of Sewage Sludge to
Cropland: Appraisal of Potential Hazards of the Heavy
Metals to Plants and Animals. Council for Agricultural
Science and Technology Report No. 64. EPA-430/9-76-013,
U.S. Environmental Protection Agency, November 1976.
173. Bingham, F. T., et al . Growth and Cadmium Accumulation of
Plants Grown on a Soil Treated with Cadmium-Enriched
Sewage Sludge. J. Environ. Qua!., 4:207-211, 1975.
174. Cunningham, J. D., D. R. Keeney, and J. A. Ryan. Phyto-
toxicity and Uptake of Metals Added to Soils as Inorganic
Salts or in Sewage Sludge. J. Environ. Qua!. 4:460-462:
1975.
175. Hughes, J. T. and P. G. Fenemore. Residue in Pasture
Following Application of a Granular Heptachlor Preparation.
New Zealand J. Agr. Res., 10:261-271, 1967.
202
-------
REFERENCES (continued)
176. Nash, R. 6. Plant Uptake of Insecticides, Fungicides, and
Fumigants from Soils. In: Pesticides in Soils and Water,
W. 0. Guenzi, ed. American Society of Agronomy, Madison,
Wisconsin, 1974. pp. 257-313.
177. Beetsman, G. B., et al. Dieldrin Uptake by Corn as
Affected by Soil Properties. Agron. J., 61:247-250, 1969.
178. Kansouh, A. S. H. and T. L. Hopkins. Diazinon Absorption,
Translocation and Metabolism in Bean Plants. J. Agr.
Food Chem., 16:446-450, 1968.
179. Moza, P., et al. Fate of 2 ,2'-Dichlorobiphenyl-14C in
Carrots, Sugar Beets, and Soil under Outdoor Conditions.
J. Agric. Food Chem. 24:881-885, 1976.
180. Jacobs, L. W., S. F. Chou, and J. M. Tiedje. Fate of
Polybrominated Biphenyl (PBB's) in Soils. Persistence and
Plant Uptake. J. Agric. Food Chem., 24:1198-1201, 1976.
181. Suzuki, M., et al. Translocation of Polychlorobiphenyls
in Soil into Plants: A Study of a Method of Culture of
Soybean Sprouts. Arch. Environ. Contam. and Tox. 5:343-
352, 1977.
182. Iwata, Y. and F. A. Gunther. Translocation of the
Polychlorinated Biphenyl Aroclor 1254 from Soil into
Carrots Under Field Conditions. Arch. Environ. Contam.
and Tox. , 4:41-59, 1976.
183. Sax, N. I. Dangerous Properties of Industrial Materials,
4th ed. Van Nostrand Reinhold Company, New York, 1975.
184. Cook, H. A., D. L. Cromwell, and H. A. Wilson. Micro-
organisms in Household Refuse and Seepage Water from
Sanitary Landfills. In: Proc. West Virginia Academy of
Science, 39:107-114, 1967.
185. Carroll, T. E., et al. Review of Land Spreading of Liquid
Municipal Sewage Sludge. EPA-670/2-75-0,49, U.S. Environ-
mental Protection Agency, 1975.
186. Elliot, L. F. and J. R. Ellis. Bacterial and Viral
Pathogens Associated with Land Application of Organic
Wastes. J. Environ. Qual. , 6:245-251, 1977.
187. Gurnham, C. F. , ed. Industrial Wastewater Control.
Academic Press, New York, 1965. 476 pp.
203
-------
REFERENCES (continued)
188. Lund, L. J., A. L. Page, and C. 0. Nelson. Movement of
Heavy Metals Below Sewage Disposal Ponds. J. Environ.
Qua!., 5:330-334, 1976.
189. Baker, D. E. and L. Chesnin. Chemical Monitoring of Soils
for Environmental Quality and Animal and Human Health.
Adv. Agron., 27:305-374, 1975.
190. Petersen, R. G. and L. D. Calvin. Sampling. In: Methods
of Soil Analysis, Part I, C. A. Black, ed. Amer. Soc. of
Agron., Inc., Madison, Wisconsin, 1965. pp. 54-72.
191. NC-118. Sampling and Analysis of Soils, Plants, Waste
Waters, and Sludge: Suggested Standardization and
Methodology. North Central Regional Publication 230
(No date). 20 p. Available from Agri. Exper. Stn.,
Kansas State University, Manhattan.
192. Richards, L. A., ed. Diagnoses and Improvement of Saline
and Alkali Soils. USDA Handbook, No. 60, 1954.
193. U.S. Environmental Protection Agency Report to the
Congress on Waste Disposal Practices and their Effects
on Ground Water. January 1977.
194. Blakeslee, P. A. Site Monitoring Considerations for
Sludge and Wastewater Application to Agricultural Land.
In: Application of Sludges and Wastewaters on Agricultural
Land: A Planning and Educational Guide, B. D. Knezck and
R. H. Miller, eds. Nor.th Central Regional Research
Publication 235, 1976.
195. Diefendorf, A. F. and D. Ausburn. Groundwater Monitoring
Wells. Public Works, 7:48-50, 1977.
196. Manual of Methods for Chemical Analysis of Water and
Wastes. EPA-625/6-74-003. U.S. Environmental Protection
Agency. Washington, D.C., 1974.
197. Standard Methods for Examination of Water and Wastewater.
American Public Health Assoc., Washington, D.C., 1975.
14th edition.
198. Kissel, D. E., C. W. Richardson, and E. Burnett. Losses
of Nitrogen in Surface Runoff in the Blackland Prairie
in Texas. J. Environ. Qual. , 5:288-293. 1976.
204
-------
REFERENCES (continued)
199
200.
201.
Baker, D. E., M. C. Amacher, and W. T. Doty.
Sewage Sludges, Soils and Crops for Zinc and
In: Land as a Waste Management Alternative,
ed. Ann Arbor Science Publishers, Inc., Ann
Michigan, 1976. pp. 261-281.
Monitoring
Cadmium.
R. C. Loehr
Arbor,
Jones, J. B., Jr. and W. J. A. Steyn. Sampling, Handling
and Analyzing Plant Tissue Samples. In: Soil Testing
and Plant Analysis, E. M. Walsh and J. D. Beaton, eds.
Soil Science Society of America, Inc., Madison, Wisconsin
1973. pp. 249-270.
U.S. Environmental Protection Agency.
Hazardous Wastes Report to Congress.
Office, Washington, D.C., 1974.
Disposal of
Government Printing
202. Metcalf and Eddy, Inc. Wastewater Engineering.
Hill Book Co., New York, 1972. pp. 410-411.
McGraw-
205
-------
TECHNICAL REPORT DATA
(Please read Inunctions on the reverse before completing)
1. REPORT NO.
EPA-600/2-7.8-140a
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
LAND CULTIVATION OF INDUSTRIAL WASTES AND MUNICIPAL
SOLID WASTES: STATE-OF-THE-ART STUDY
Volume i - Technical Summary and Literature Review
5. REPORT DATE
August 1978 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Tan Phung, Larry Barker, David Ross, and David Bauer
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
SCS Engineers
4014 Land Beach Boulevard
Long Beach, California 90807
10. PROGRAM ELEMENT NO.
1DC618
11. CONTRACT/GRANT NO.
68-03-2435
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research LaboratoryGin. ,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final, July 1976 to Jan. 1978
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer:
See also Vol. 2,
Robert E. Landreth (513) 684-7871
EPA-600/2-78-140b
A review of the available literature on land cultivation of industrial waste-
water and sludge, and municipal solid waste was conducted. This review was
supplemented by field investigations at 10 operating sites, including soil and
vegetation analyses.
Soil is a natural environment for the inactivation and degradation of many
waste materials through a variety of soil processes. Land cultivation is a disposal
technique by which a waste is spread on and incorporated into the surface soil.
Depending on waste characteristics, the disposal program can be either related to
agriculture or solely a disposal practice.
Volume 1 is a technical summary and literature review. It contains information
about land cultivation practices, waste* characteristics and quantities, mechanisms of
waste degradation, effects on soil properties and plants, regulations, site selec-
tion, operation, environmental impact assessment, site monitoring, site conceptual
design, and case study summaries. Cited are 202 references.
Volume 2 summarizes the results of field investigations and case studies. It
covers four field studies, six case studies, and a section on nonstandard disposal
or utilization techniques for hazardous wastes. Field data was collected to evalu-
ate operational procedures, costs, environmental impacts, and problems associated
with land cultivation at the individual sites.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Industrial wastes
Refuse disposal
Land reclamation
Soil chemistry
Soil microbiology
Plant nutrition
Plant physiology
Waste disposal
Biodegradation
Land application
13B
13. DISTRIBUTION STATEMENT
-' Release unl imi ted
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
220
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
206
U. S. GOVERNMENT PRINTING OFFICE: 1978-757-140/1432 Region No. 5-11
------- |