United States
Environmental Protection
Agency
Municipal Environmental Research EPA-600/2-80-090
Laboratory August 1980
Cincinnati OH 45268
v>EPA
Research and Development
Wastewater Solids
Utilization on Land
Demonstration
Project
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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.
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EPA-600/2-80-090
August 1980
WASTEWATER SOLIDS UTILIZATION
ON LAND DEMONSTRATION PROJECT
by
The Ocean County Sewerage Authority
Bayville, New Jersey'08721
and
Cook College
Rutgers University
New Brunswick, New Jersey 07103
Grant No. S 801871
Project Officer
Kenneth Dotson
Wastewater Research 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
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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
recommendation for use.
11
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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 com-
plexity 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 solution and it involves defining the problem, measur-
ing its impact, and searching for solutions. The Municipal
Environmental Research Laboratory develops new and improved
technology and systems for the prevention, treatment, and man-
agement 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.
Using spent solids on land for its nutrient value is not
new. The additions of raw waste as a fertilizer has been prac-
ticed extensively for centuries in most underdeveloped nations.
However, the applications of municipal digested wastewater
solids has been practiced on a relatively small scale in this
country and only for a few generations. The ever-increasing
population and residues from higher degrees of treatment each
contribute to a solids disposal problem which is already diffi-
cult and complex. Ultimate solids disposal is no longer a
matter of simple disposal by "dilution" or "reuse" but one of
coping with a series of interacting environmental limitations.
This investigation was undertaken for the purpose of
determining the feasibility of utilizing wastewater solids on
sandy coastal plain soils in conjunction with environmental
considerations such as grouhdwater quality, odors, heavy metal
distribution and wildlife feeding on amended crops needed reso-
lution so that reuse of digested sludge could be placed in prop-
er perspective.
111
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The cost of applying wastewater solids to land will have
a considerable bearing on whether or not reuse becomes a viable
alternative to other practices for ultimate disposal. Success
may be measured on how little it costs (or how little you lose)
to meet this first priority. Solving the ultimate disposaj.
problems has enormous value to society. Recovering as much of
the costs as possible has a salutary effect. However, to set
one's goals only as providing a reuse product equivalent to or
competitive with an artifical fertilizer can be misleading
and defeating. Initially, the two products are totally dif-
ferent in composition and/or costs per unit weight to produce.
Secondly, the waste solids represent a burden which is growing
continuously and must be resolved profitably or not.
This report represents a condensation of a much larger
effort. Approximately 250,000 separate measurements were made
over a four-year period. Those interested in additional de-
tail may wish to examine other data collected on this project.
Inquiries concerning the availability of such data should be
made directly to the Ocean County Sewerage Authority.
It is hoped that this report will provide the reader with
additional insight into (a) the permissible loadings on sandy
type soil, (b) techniques for monitoring crop growth, (c) soil
changes, (d) groundwater quality, (e) groundwater movement,
(f) heavy metal uptake, (g) wildlife feeding, (h) aerosol for-
mation, and (i) crop management considerations. Although
recommendations are made for additional study much valuable
information is offered to those interested in evaluation and
control of wastewater solids application on land.
This report presents results of a study that was conducted
to identify alternative methods of treating and disposing of
wastewater sludge. It provides information about the beneficial
effect of using sewage sludge on sandy soils with low pro-
ductivity. Insight into permissible application rates, tech-
niques for monitoring crops, effects on groundwater quality,
crop responses, wildlife response, and effect on air quality
are also provided.
IV
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ABSTRACT
This report is a condensed version of a much larger study
and presents in summary form the guidelines, limitations, and
environmental changes associated with land applications of di-
gested municipal wastewater solids under the conditions of
the study. The environmental impact on different soils at
various application rates was investigated. The study was
conducted over a four-year period, but sludge was applied
during the first three years.
Some of the salient considerations were the effect of
sludge on groundwater quality, groundwater movement, crop
production, wildlife, microbial aerosols, odor; soil prop-
erties, crop management, heavy metal uptake and monitoring
needs.
This report was submitted in fulfillment of Grant No.
S-801871 by The Ocean County Sewerage Authority under the
partial sponsorship of the Environmental Protection Agency,
The report covers the period June, 1972 to October, 1976.
v
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CONTENTS
Foreword.
Abstract.
Contents
Figures
Tables
Acknowledgements
1. Introduction
Background. .
Obj ective. . . . .
Participants • • • •
2. Discussion of Initial Objectives and
Summary Observations
3. Recommendations
4. Selection of Application Sites
Location and Description
Geology
Soil Series
Hydrology .-
5. Application Sites
Native'Vegetation
Site and Plot Layout
Crop Establishment
Loading Rates
Well Codes
• Groundwater Monitoring.
Groundwater Table Fluctuations
, Groundwater 'Movement
Groundwater Velocity-Tracer Tests
6. Wastewater Solids Applications
Source • • • • •
Characteristics ,
Application Methods and Techniques....,
Loading and Distribution of
Wastewater Solids
7. Agronomic Aspects
Growth of Native Vegetation ,
Effects of Solids Application on Crops,
Chemical Contents of Plant Tissues....,
Response of Cool Season Grass
Mixture to Sludge Applications
111
v
vii
ix
xii
xiv
1
2
3
5
25
27
27
31
33
37
37
38
39
39
43
46
46
54
57
57
61
65
67
69
77
78
VI1
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CONTENTS (Continued)
8.
9.
Soil Water
Soil Temperature
Surface Accumulations
Quantities of Elements Remaining in
the Sludge on the Soil Surface
After 3 Years of Application
Effects of Sludge on Soil Profiles...
Microbial Aerosols and Odors
Microbial Aerosols ,
Odors
Groundwater Quality
Introduction (Contamination vs.
Pollution) ,
Sampling Schedule and Analysis ,
Baseline Groundwater Quality ,
Groundwater Quality After Application,
Groundwater Contamination Beneath
the Natural Vegetation Plots
85
88
93
93
96
102
105
108
108
111
111
127
Vlll
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FIGURES
Number
1.
2.
3.
»
4.
5.
6.
7.
Page
Map of New Jersey Showing Location of Study Areas.... 28
Location of Colliers Mills, Downer Soil Site 1 29
Location of Webbs Mill, Lakewood Soil Site 1 and
Woodmansie Soil Site 2
30
Particle Size Distribution in the Profile of Downer
Loamy Sand 34
Particle Size Distribution in the Profile of Lake-
wood Sand 35
Particle Size Distribution in the Profile of
Woodmansie Sand . • 36
Colliers Mills Site Showing Distribution of. Wells
and Equipment In or Near the Plots 41
8. Webbs Mill Site 1 Showing Distribution of Wells and
Equipment In or Near the Plots
42
9. Webbs Mill Site 2 Showing Distribution of Wells and
Equipment In or Near the Plots 43
10. Diagram of Skim Sampler 44
11. Diagram of Profile Sampler 45
12. Water Level Fluctuation in Well CM15A and Precipita-
tion Data at Colliers Mills Site 1, 1973 47
13. Water Level Fluctuation in Well CM15A and Precipita-
tion Data at Colliers Mills Site 1, 1974 48
14. Water Level Fluctuation in Well CM15A and Precipita-
tion Data at Colliers Mills Site 1, 1975... 49
15. Water Level Fluctuation in Well CM15A and Precipita-
tion Data at Colliers Mills Site 1, 1976 50
IX
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FIGURES (Continued)
Number
Page
T6. Water Table Map at Colliers Mills Site 1,
August 27, 1975 51
17. Water Table Map at Webbs Mill Site 1, July 9, 1974 52
18. Water Table Map at Webbs Mill Site 1, April 5, 1976... 53
19. Sketch Showing Well Distribution Used in
Tracer Test 55
20. Sewage Sludge Application Unit - Side View 62
21. Sewage Sludge Application Unit - End View..... 63
22. Soil Variations with Depth, Determined by Neutron
Probe Under Various Conditions of Lakewood Sand
on July 17, 1974
23,
24,
25,
Soil Water Variations with Depth, Determined
by Neutron Probe under Various Conditions of
Lakewood Sand on July 31, 1974
Soil Water Variations with Depth, Determined by
Neutron Probe under Various Conditions of
Lakewood Sand on September 10, 1974
Soil Water Variations with Depth, Determined by
Neutron Probe under Various Conditions of
Lakewood Sand on October 10, 1974
86
87
89
90
26. Specific Conductance Response over Time for
Groundwater Monitoring Well 118
27. Nitrate-Nitrogen Concentrations over Time for
Groundwater Monitoring Well 119
28. Cyclic Fluctuations of Specific Conductances in
Groundwater at Webbs Mill. 120
29. Cyclic Fluctuations of Nitrate-Nitrogen at
Colliers Mills Wells CMI13B and CMI13E 121
30. Peak and Average Nitrate-Nitrogen Breakthrough
Concentration for "B" and "C" Well
Beneath 22.4 t/ha/y Plot 122
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FIGURES (Continued)
Number
31.
32.
33.
34.
35.
36.
Nitrate-Nitrogen Concentration over Time for
Groundwater Monitoring Well in Downer
Loamy Sand
• 131
Nitrate-Nitrogen Concentration over Time for
Groundwater Monitoring Well in Lakewood
Sand. .'...132
Nitrate-Nitrogen Concentration over Time for
Groundwater Monitoring Well in Woodmansie
, Loamy Sand .....133
Specific Conductivity and Nitrate-Nitrogen Response
for Well WM21C as Related to Precipitation and
Fluctuation in Groundwater Table , • • • -138
Specific Conductivity and Nitrate-Nitrogen Response
for Well WM12B as Related to Precipitation and
Fluctuation in Groundwater Table 139
Specific Conductance Response over Time for Groundwater
Monitoring Well on Webbs Mill Lakewood 44.8
t/ha/y Plot .140
XI
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TABLES
Number
1. Total Amounts of Metal That Can Be Applied
to the Soil 9
2. Metal Characteristics of Ocean County Sludge
and Maximum Allowable Metal and Sludge
Loading 10
3. Relative Yearly Changes in Contaminant Concen-
tration Beneath Individual Application Plots
from Wells B and C, 1973 to 1976 12
4. Average Increase of Contaminant in Groundwater
Samples over Background Levels of Selected
Parameters 14
5. Constituents For Which Wastewater Solids
Were Analyzed. , 58
6. Wastewater Solids Characteristics 60
7. Concentration of Elements in Foliage of Native
Species With and Without Sludge 70
8. Grass Harvested from Sludge Plots in 1974 74
9. Grass Harvested from Sludge Plots in 1975 75
10. Grass Harvested from Sludge Plots in 1976 76
11. Plant Species Composition as Affected by Grazing
and Sludge Application on Lakewood Sand in 1974... 79
12. Yields of Cool-season Grass Mixture Plots on
Lakewood Sand for 1974 81
13. Yields of Cool-season Grass Mixture Plots on
Lakewood Sand for 1975 . 82
XII
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TABLES (Continued)
Number Page
14. Chemical Analysis of Cool-season Grasses Over a
3-year Period as Affected by Sludge Rate 83
15. Temperature of Lakewood Sand at Various Depths as
Affected by Cover and First Year's Appli-
cation of Sludge 91
16. Percent Water in Lakewood Sand at Various Depths
Under Forest Vegetation With and Without
Sludge on Four Dates in the Second Season of
Application • • • 92
17. Depth of Sludge After 3 Years of Sludge Application .
to Three Soils, by Two Modes of Application -
June 30, 1976.,, •• 94
18. Weight of Sludge Accumulation on the Soil Surface
After 3 Years of Sludge Application to Three
Soils by Two Modes of Application - June 30, 1976. 95
19. Kg/ha of Elements Remaining on the Surface in the
Sludge After 3 Years of Application 97
20. Groundwater Monitoring. , .....109
21, Modified Groundwater Analysis ,.. "..109
22. Average Background Water Quality Before Application
of Wastewater Solids , .......112
23. Contaminant Concentration Beneath the Natural
Vegetation Plots , ..129
, 24. Soil pH Beneath Natural Vegetation Plots 130
25. Relative Yearly Changes in Contaminant Concen-
trations Beneath Individual Application Plots
from 1973 to 1976 ; 136
26. Average Increase of Contaminant Breakthrough Over
Background Level of Selected Parameters 141
XI11
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ACKNOWLEDGMENTS
There were three primary participating groups involved in
the execution of this study: (.1) U.S. Environmental Protection
Agency and The Ocean County Sewerage Authority, (2) sub-con-
tractors, authors and researchers, and (3) group discussions
which provided specific expertise and guidance periodically.
Policy and scope of overall effort were defined by the pro-
ject's Coordinating Committee which consisted of representatives
from the major contributors to the project study.
Coordinating Committee
Mr. Michael Gritzuk, Executive Director
Ocean County Sewerage Authority
Mr. William Kara, Chief, Hydrolog.ic Studies Section,
U.S. Geological Survey
Dr. A. Joel Kaplovsky, Chairman, College of Agriculture and
Environmental Science, Department of Environmental Sciences,
Rutgers University
Mr. Robert Olsen, Special Assistant, Water Division,
U.S. Environmental Protection Agency
Mr. Joseph M. Penkala, Senior Wildlife Biologist,
New Jersey State Department of Environmental Protection
Project Officer of USEPA Research and Development Grant
Mr. Kenneth Dotson, Project Officer, Ultimate Disposal Section,
Municipal Environmental Research Laboratory, U.S. Environmental.
Protection Agency, Cincinnati, Ohio
Supervisors, Researchers § Authors
Dr. Robert B. Alderfer, Research Professor, College of Agricul-
ture and Environmental Sciences, Soils and Crops Department,
Rutgers University
Dr. Donn Derr, Associate Professor, Department of Agricultural
Economics, Rutgers University
xiv
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ACKNOWLEDGMENTS (Continued)
Dr. Robert Duell, Associate Research Professor, College of
Environmental Science, Soils and Crops Department, Rutgers
University
Dr. Emil J. Genetelli, Professor, College of Agriculture and
Environmental Sciences, Department of Environmental Sciences,
Rutgers University
Mr. William Kam, Chief, Hydrologic Studies Section,
U.S. Geological Survey
Dr. A. Joel Kaplovsky, Coordinator, College of Agriculture and
Environmental Sciences, Department of Environmental Sciences,
Rutgers University
Mr. Charles Reed, Professor, Department of Biology and
Agricultural Engineering, Rutgers University
Additional Contributors
Mr. E.P. Hahn, N.J. State Department of Environmental
Protection
Mr. G.P. Howard, N.J, State Department of Environmental
Protection -
H, Kasenbaeh, N.J. State Department of Environmental Protection
Mr, R. Lund, N.J. State Department of Environmental Protection
Dr. D. Markus, Soils and Crops Department, Rutgers University
Dr. R. Mason, U.S. Environmental Protection Agency Region II
Dr, W. Roberts, Biological and Agricultural Engineering,
Rutgers University
Mr. C. Ryder, Neptune Sewerage Authority
Primary Work Group at Rutgers University
D. Chen, Graduate Assistant, Department of Environmental
Sciences
C. Doxon, Principal Clerk Stenographer, Department of Environ-
mental Sciences
G. Dozsa, Laboratory Technician, Department of Environmental
Sciences •
T. Flet, Senior Research Farmer, Department of Biology and
Agricultural Engineering
xv
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•ACKNOWLEDGMENTS (Continued)
R. Habrukowich, Graduate Assistant, Department of Environmental
Sciences
A. Higgins, Research Associate, Department of Biology and
Agricultural Engineering
D. Plat, Research Associate, Department of Soils and Crops
P. Strom, Teaching Assistant, Department of Environmental
Sciences
There were many additional people too numerous to mention
who spent time on the project in various capacities.
xvi
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SECTION 1
INTRODUCTION
BACKGROUND
The disposal of wastewater sludges is probably the most
complex problem with which the scientist, engineer, environ-
mentalist and treatment plant operator is faced today in
the field of wastewater management. This problem is being *
rapidly compounded as the volumes of wastewater solids continue
to increase. Many communities must upgrade existing treatment
facilities or implement new facilities to comply with current
Federal and State regulations requiring higher degrees of .waste-
water treatment. Secondary treatment doubles the amount of
wastewater solids generated by primary treatment alone. Adding
advanced wastewater treatment produces 25 percent more waste-
water solids than secondary treatment alone. Coincident with
the increase in volume of wastewater solids is the constraints
from more stringent disposal regulations, increased costs, and
increasing concern for adverse environmental impacts of conven-
tional disposal methods.
For example, recent claims of beach contaminations and'
massive fish kills have made- it difficult to continue with
ocean disposal. The scarcity of large tracts of land and
the potential of contamination of the underlying groundwaters
have limited the availability of sites for landfill operations.
Stringent air pollution control requirements coupled with the
high cost of fuel have significantly curtailed the use of in-
cinerators. It has become imperative that we find alternate
means of wastewater solids disposal that are environmentally
suitable and economically possible.
This project was conceived to demonstrate that wastewater
solids could be disposed of via a reuse method in an environ-
mentally acceptable manner. Specifically, the project was
conceived to demonstrate that liquid digested domestic waste-
water sludge can be utilized as a soil conditioner and
fertilizer for the cultivation of crops and enhancement of
native vegetation in marginally-productive coastal lands. The
usefulness of the enriched native vegetation and crop produc-
tion as a source of wildlife feed was also evaluated.
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A principal objective of the project was to determine
optimum loading rates of wastewater solids that can be applied
to the land contingent upon the effects of such loading on the
underlying groundwater quality. Accordingly, a major section of
this report was devoted to defining groundwater contamination
and establishing groundwater contamination levels which might
be considered for development of groundwater quality standards
throughout the Atlantic Coastal area of the United States.
The project was conducted in Ocean County, New Jersey
which is a northeastern coastal area of the country. The
sandy soils predominating in the coastal area are generally
low or practically void of nutrient and organic content and
as such are only of marginal value for agricultural purposes.
In order to make the project broadly based, and thereby be
applicable to other coastal areas of the country, three dis- .
tinct types of soils were selected for the demonstration. The
soils selected are considered to be common to the eastern
coastline of the country.
The project commenced in July 1972 with plot preparation
followed by well installation. The first application of
wastewater solids was made in the spring of 1973. Wastewater
solids applications were continuously made over .the growing
seasons for a three-year period terminating in .the fall of
1975. To determine the residual effects of these applications,
groundwater monitoring and analyses continued another full
year terminating in late fall of 1976.
PROJECT OBJECTIVES
The primary objectives of the project were as follows:
1. To determine the effects on groundwater quality of
using soil as a disposal medium for wastewater solids,
and to determine groundwater pdllutional restraints
based upon hydrologic considerations of the sites
selected for disposal of solids.
2. To determine the quantity and frequency of wastewater
solids application, and the length of time that waste-
water solids may be applied to the soil without un-
desirable effects.
3. To evaluate the prolonged use of soil as a recipient of
sludge and determine how it affects both groundwater
and soil composition.
4. To determine if disposal of wastewater solids on
marginally productive lands could result in an increase
in productivity of such lands.
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5. To determine the effects of solids application on
native vegetation and crop production.
6. to observe wildlife reactions to grazing of crops grown
under this process.
7. To determine effects of wastewater solids applications
on air quality.
8. To determine the need for monitoring systems and other
restraints within the area of the application.
PROJECT PARTICIPANTS ' • • _ .
This demonstration project was developed as a joint multi-
disciplinary project between the following participating
agencies:
1. Ocean County Sewerage Authority
2. Rutgers - The State University of New Jersey
3. State of New Jersey, Department of Environmental
Protection
4. U.S. Environmental Protection Agency
5. U.S. Department of the Interior-Geological Survey
Technical direction, policy matters, and overall project
coordination was delegated to a Coordinating Committee con-
sisting of one representative from each a~f the participating
agencies. •
In addition to being involved in the overall development
and execution of the project, the participating agencies were
responsible for the performance of one or more of the following
major functions:
Rutgers University
Site Selection
Analytical determinations
Selection and management of types of vegetation ground
cover
Application methods and techniques
Aerosol transport
Groundwater monitoring
The Departments of Environmental Science, Agricultural
Engineering and Soils and Crops,of the State University
participated in this project.
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U.S. Geological Survey
Site selection
Subsurface geology
Evaluate changes of soil moisture and water quality
through the unsaturated zone
Chart groundwater flow and evaluate groundwater quality
Rainfall data
State of New Jersey Department of Environmental Protection
Effects on native vegetation
Wildlife reactions
The Divisions of Fish, Game and Shellfisheries and Water
Resources participated in this project.
U.S. Environmental Protection Agency
Grantor of federal grant funds
Project overview
Ocean County Sewerage Authority
Grantee and banker
Project administration
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SECTION 2
DISCUSSION OF INITIAL OBJECTIVES AND SUMMARY OBSERVATIONS
The project was undertaken with the expressed purpose of
responding to a specific list of objectives. The following
summary statements were abstracted from the voluminous data
collected since the initiation of the study in July 1972.
Objective 1.
To determine the degree of contamination
crF groundwater from land disposal of was"te-
water solids, and to ascertain the effects
of hydrologic characteristics upon waste-
water solids~application rates to meet
established standards.
The more mobile anions and cations (Na+, CaH
Mg"
Cl"
804", and NOj ) show measurable groundwater concentrations
above background and control levels directly beneath the
application plots. Contamination of the groundwater with heavy
metals was generally not detectable, with the possible exception
of copper and zinc.
There appears to be no evidence of coliform contamination
in any wells due to the application of wastewater solids. A
few samples, including some from the control plots, did contain
one to four coliforms (per 100 ml) at times.
Upon installation of the wells there was contamination
from the solvent used to connect the PVC well casing. After
many flushings of the wells, Total Organic Carbon (TOG) con-
centrations stabilized between 0.0 and 3.0 mg/1. Total Organic
Carbon concentrations occasionally exceeded recorded baseline
concentrations in most wells. Peak TOG concentrations of
24 mg/1 and 20 mg/1 were recorded for wells located at the cen-
ter of application sites.
Groundwater samples for many observation wells showed
little or no change in any chemical constituent concentration
but in other wells, peak concentrations of many constituents,
had increased by more than two (2) orders of magnitude'
from reported baseline levels. Contaminants were at peak
concentrations in winter and spring months when precipitation
exceeded evapo.transpiration.
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The velocity of groundwater flow ranged from 0.62 to 0.69
ft per day at the Webbs Mill sites and 1.1 to 1.6 ft per day
at Colliers Mills. At these rates, the affected groundwater
will reach the surface system within one year at the Downer
soil site and four years at the Woodmansie soil site. The
extent of contaminant attenuation between the loading source
and the stream must be considered for the purposes of this
study. The concentrations of any constituents reaching the
stream will be controlled largely by the loadings, attenuation
(dilution) and management practices.
For a particular plot, the concentration of the chemical
constituent in an observation well was also spati ally depen-
dent on the location of the well with respect to the direction
of groundwater flow and whether the wells were located within
or downgradient of the application site. Those wells designat-
ed as "A", "B", and "C" were within the point of application
while "D" and "E" wells were 30.5 m (100 ft) and 61 m (200 ft)
downgradient of the application plots, respectively. Although
Wells "A", "B", and "C" were within an application plot,
Well "A" was installed on the upgradient fringe of the plot,
Well "B" was in the center, and Well "C" was installed at the
far downgradient fringe of the application plot. One would
expect little or no change in groundwater quality for Well "A"
because uncontaminated groundwater is always flowing through
this well. Therefore, the evaluation of groundwater quality
from the application of wastewater solid (breakthrough) is
best interpreted from the data obtained from Wells "B" and
"C", Concentrations of*chemical constituents in Wells "B"
and "C" within the same plot can also vary significantly due
to the heterogeneity of soil; due to clay lenses or coarse
sandy strata in the soil profile and the position of the wells
relative to the. changing direction of flow of contaminants.
The "D" and "E" wells were installed 30.5 m and 61 m
downgradient of the application site, according to the first
potentimetric maps constructed at the beginning of applications
in 1973, However, it was found at a later date that the direc-
tion of flow shifted under changing conditions of flow gradients
recharge, and discharge. The concentration of chemical composi-
tion reported for these wells were affected by the changing
flow direction. As a result, the values reported were consider-
ably lower than the representative concentration which lies
directly along the line of flow. Additionally, samples (skim
samples) fron) the top of the watertable at downgradient wells
a,re also somewhat diluted because these wells were not subject
to_vertical breakthrough of sludge-related chemicals, but are
still subject to groundwater recharge. The profile sample data
were also used to more clearly define the distribution of con-
stituents downgradient from the source plots.
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Objective 2.
Tp_ determine the quantity and frequency
of applications, and the length of time
'that wastewater solids may^ be applied to
the soil without undesirable effects.
Sludge Application on Natural Vegetation Plots
The applications of wastewater solids on natural vegetation
plots caused a significant deterioration of groundwater quality
beneath the plot. The naturally acid soil conditions (circa
pH 4.5) contributed to concentrations of many sludge-related
constitutents approaching and even exceeding the values reported
for the heaviest loaded (89.6 t/ha/y) applications. Contamin-
ant concentration beneath the three natural vegetation plots
seem to vary according to soil pH. Groundwater contamination
was the greatest beneath the Woodmansie plot where the average
soil pH was as low as 4.3. These acid conditions significantly
increased the.mobility of many sludge constitutents, particular-
ly ammonia nitrogen, organic acids (TOG) and even heavy metals.
Compounding the effect of the acid soil conditions is the lack
of harvesting of a cover crop which would remove many of the
sludge constituents from the application site. Therefore, the
natural vegetation site becomes a repository for groundwater
contaminants.
From these observations it appears that the application of
wastewater solids is not suitable for natural vegetation areas
that are typical of the New Jersey Pine Barrens if the 44.8
t/ha/y loading rate is utilized without prior pretreatment of
soils. Unfortunately, the loading rates were not varied on the
natural vegetation sites and therefore it is not possible to
establish a loading rate which will result in a minimal deter-
ioration of groundwater.
Sludge Application Rates for Cultivated Crops
It has been reported by Sommers (1) that the determination
of annual application rates must be contingent upon the nitrogen
and cadmium content of the sludge and the specific crop selected
(1)
Adapted from Sommer, L. E., "Principles of Land Applica-
tion of Sewage Sludge". In Design Seminar for Sludge
Treatment and Disposal, Environmental Protection
Agency, Cincinnati, Ohio, 1977.
7 '
-------
for cultivation. The number of years of sludge application is
limited by heavy metal concentrations. Employing Sommers' for-
mula, calculations were made utilizing OCSA collected data with
the following results:
1. Nitrogen Requirements
Tons sludge/acre = crop requirement - residual nitrogen
.pounds available/ton sludge
Crop nitrogen requirement for double cropping of rye
and Midland bermudagrass is approximately 350 Ibs/acre.
Based on sludge characteristics the pound of available
nitrogen per ton sludge ranged from 50 to 63 Ibs/ton
sludge. Residual nitrogen was calculated as 13 Ibs
after the 1st year application and 26 Ibs after the
second year.
Since sludge was surface applied, doubling the allow-
able rate is indicated because of loss of ammonia
nitrogen by volatilization. Thus the nitrogen require-
ment limits the annual loading rate to a maximum of
10-12 tons/acre (.22.4 - 26.9 t/ha/y) .
2. Cadmium Annual Limitations
4
Tons sludge/acre = 2 Ibs Cd/acre
pp~m Cd x . 002
Cadmium in the sludge applied averaged 17.9 ppm on a
dry basis. Therefore, the annual allowable, sludge
application rate based on Cd additions would be 56 dry
ton/acre.
3. Heavy Metal Limitations
The total amounts of lead, zinc, copper, nickel, and
cadmium suggested on agricultural soil from land
application of sewage sludge was developed by coopera-
tive efforts of regional research projects on Nc-118,
W-124, SEA, and USDA. Table 1 lists the total amounts
of metal that can be applied to the soil.
-------
TABLE 1.* TOTAL AMOUNTS OF METAL THAT CAN BE APPLIED TO
THE SOIL
Metal
Soil CEC, meq/lOOg
5-15
15
Ibs/acre
Pb
Zn
Cu '
Ni
Cd
500
250
125
50
5
1000
500
250
100
10
2000
1000
500
200
20
The suggested limits are based on soil cation exchange cap-
acity (CEC). The soils of Ocean County, New Jersey have a low
CEC ranging from 1-5 meq/lOOg.
The total tons of sludge applied per acre can be calculated
from the following equation:
Tons sludge/acre = total Ib metal/acre
ppm metal x 0.002
The average metal characteristics of Ocean County sludge
suggested maximum metal loadings and calculated tonnage of
sludge necessary to exceed the allowable loadings is summarized
in Table 2.
Table developed by cooperative efforts of various regional
projects NC-3L18 and W-124 and SEA, USDA. (1)
-------
TABLE 2. METAL CHARACTERISTICS OF OCEAN COUNTY SLUDGE AND
MAXIMUM ALLOWABLE METAL AND SLUDGE LOADING
Concentration
in Sludge
Gng/g)
Maximum Allowable
Kilograms of Metal
per Hectare
Total Allowable
Metric Tons of
Sludge per Hectare
Pb
Zn
Cu
Ni
Cd
360
2653
913
43
17.9
560
280
140
56
5.6
1557
105
155
1301
314
From Table 2, it can be seen that sludge application is
limited by Zinc (.lowest amount] or 47 tons per acre.
In summation, the annual sludge rate based on nitrogen
required for cropping rye and Midland bermudagrass was found to
be 10-12 tons/acre C22.4 t/ha/y), if surface application tech-
niques are utilized. Additionally, lime and fertilizer potass-
ium C'Kl would have to be applied to obtain optimum yields. If
the application site was continuously cropped and 10 tons/acre/
year (22.4 t/ha/y) of sludge were applied, the site could be
utilized for approximately 5 years. The 5-year life span would
be limited by the total allowable zinc loading. Stripping
surface accumulated sludge would appreciably extend the life of
the site for sludge application purposes.
Based on groundwater quality data obtained from experi-
mental application plots in Ocean County, New Jersey, the 10
tons/acre/year (22.4 t/ha/y) sludge loading rate does not
result in significant contamination of the groundwater quality.
Therefore, surface application of wastewater solids at 10 tons/
acre/year (22.4 t/ha/y) appears to be environmentally
acceptable from a groundwater quality aspect for a period of
5 years.
Other studies indicate that the population of denitri-
fying soil micro-organisms increases with years of manure
added to the soil, so the rate that land could accommodate
might increase with time. Nitrifying inhibitors might be
applied to reduce groundwater contamination by nitrates.
i
The surface accumulation after 3 years of application was
appreciable (particularly at the highest loading rate) and
could be removed for sale as a soil amendment, or incorporated
to provide additional nutrients to crops and increase the
10
-------
nutrient and moisture retention capacity of the soil. If accum-
ulated surface sludge is skimmed off for sale there should be no
need to "rest" the site. If a 3-year accumulation is tilled in,
sufficient nutrients may be released to warrant cessation of
applications .until the flush of nitrogen is dissipated.
Initially the 22.4 t/ha (.10 TA) rate did not appear to
supply sufficient nutrients for good crop production and N
deficiencies were evident on the Midland bermudagrass. The
44.8 t/ha resulted in better production of grass, but the 89.6
t/ha did not appear excessive even when applied to cool season
perennial grasses so as to inundate regrowth in July. Although
this is an example of gross mismanagement it served to illus-
trate crop tolerance. Crop injury developed when heavy appli-
cations were made to grass that was tall enough to harvest
.as hay crop.
With proper site selection, diversification of cropping
systems and logical coordination of sludge applications with
overall management, the application of sludge from residential
communities at rates of 44,8 t/ha/y or more should be practical.
However, further studies are needed.
Objective 3,
To Determine How the Prolonged Use of Soil a_s_
_a Tyastewater Solids Receptor Affects Ground-
water and Soil Quality
The cumulative impact of wastewater solids application on
groundwater quality was studied over a four -(.4) year period.
Application of wastewater solids in Ocean County was initiated
in May 1973. and was applied for three (":3T years until October
19.75. No solids w.ere applied during the late fall and winter
months. @roundwater monitoring was also performed during this
period and was continued for .an additional year through
November 1976, thus- a complete year of grouhdwater quality
data was obtained after wastewater solids applications were
discontinued.
Table 3 summarizes the Relative Yearly Changes in contam-
inant concentrations for the 12 wastewater solids application
plots. Contaminant concentrations beneath the 22.4 t/ha/y
application plots initially increased, but then stabilized
after two years of wastewater solids applications. At the
other extreme, contaminant levels beneath the.sandy soil
Lakewood 44.8 t/ha/y and 89.6 t/ha/y plots steadily increased
over the four-year study. Contaminant concentrations also
increased beneath .the Woodmansie 44,8 t/ha/y plot during all
four years of the project, however the increase was very small
and gradual as compared to the breakthrough concentrations
observed at the Lakewood plot receiving the same wastewater
s.olids loading.
11
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12
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Beneath all other plots, contaminant breakthrough concentrations
increased during the first three years of the study, but de-
creased or remained stable during the fourth and final year of
sampling. Although a decrease in contaminant levels was observed
at many plots, in no case did. the contaminant concentrations of
such sludge-related constituents as chloride, sulfate, calcium
and nitrate decrease to background levels.
The application of wastewater solids in Lakewood soils
appeared to produce the greatest leaching of contaminants into
the groundwater. The Woodmansie soil has the lowest contaminant
concentrations probably because of considerable silt and clay
development in the lower subsurface and substratum of the soil.
However, this is contrary to the expected, because the Wood-
mansie soil is more acid than Lakewood or Downer soils. Where
soil characteristics were similar to that of a coarse sand with
minimal clay development, even the low wastewater solids loading
rate of 22.4 t/ha/y can cause contaminant leaching. Contaminant
leaching according to soil type and solids loading rates were as
follows:
Loading Rate
t/ha/y
22,4
44.8
89.6
Contaminant Leaching According
to Soil Series
Lakewood Downer Woodmansie
Lakewood Downer Woodmansie
Lakewood Downer Woodmansie
Tt should be noted however, that the above observations are
not similar to findings reported for Well "B" on the 22.4 Wood-
mansie application plot because this well was inadvertantly in-
stalled in a sand that is not within the range of characteristics
of the Woodmansie soil series. Understandably, this particular
well demonstrated contaminant leaching rates almost as high ,as
the levels observed beneath the Woodmansie 89.6 t/ha/y plot.
Contaminant breakthrough concentrations were- compared to
National-Interim- Primary-Drinking Water Regulations proposed by
the U.S. Environmental Protection Agency and the Potable Water
Standard established by the State Department of Environmental
Protection of the State of New Jersey. These standards were
compared to the average concentrations observed at each appli-
cation plot. A total of 23 groundwater constituents were tab-
ulated according to plot loading rates and soil type. Table 4
presents the average of contaminant breakthrough concentrations
for these 23 constituents. Two additional distinctions per-
taining to groundwater quality are also identified in Table 4
(1) when the contaminant concentration is at or above the
drinking water standard and (2) when the contaminant concentra-
tion is within 50% of the maximum limit.
13
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Heavy metals did not appear to have a significant impact
on groundwater quality. The average breakthrough concentrations
of all heavy-metals were generally equivalent to or slightly
above the natural background levels. When a marginal increase
in metal concentration was observed, particularly for zinc and
copper (refer to the Lakewood 89.6 t/ha/y and Woodmansie natural
vegetation plots), it was well below the maximum contaminant .
limits for potable water.
The averages of contaminant concentrations beneath individ-
ual plots were compared with potable drinking water standards.
The p'eak concentrations were not considered in this comparison.
It appeared that the average contaminant concentration was
more representative of the long-term response o,f the groundwater
system to contaminant leaching, while the peak concentration
was only the maximum level observed at only one single point
in time.
Specific organic compounds were not identified in ground-
water samples. Only a coarse measurement of total organic car-
bon was obtained for each sample. Total organic carbon was
found to have increased above the background level beneath many
of the plots (Table 4). The breakthrough of organic carbon
as measured by TOG tends to indicate that trace organics may
have entered the groundwater. This is particularly true for
those plots receiving the higher wastewater solids loadings,
Lakewood 89.6 t/ha/y plot and where soil conditions were ex-
tremely acid (as was the case with all the natural vegetation
plots) .
Nitrate-nitrogen was the limiting groundwater chemical
constituent with respect to drinking water standards. Addi-
tionally, average concentrations of total dissolved solids,
chlorides, sulfates, and total hardness (calcium and magnesium)
were approaching, and in many cases exceeding the recommended
limit beneath the following locations: (a) plot receiving
89.6 t/ha/y of wastewater solids, (b) natural vegetation plots
(Downer and Woodmansie), and (c) where soil characteristics were
similar to that of a coarse sand. • For the Downer and
Woodmansie soils, it would appear a surface application of
wastewater solids loading rate in excess of 22.4 t/ha/y
and possibly as much as 44.8 t/ha/y could be applied without
violating the potable water, standards downgradient from the
application site. In 'the case of the more sandy Lakewood
soil, the maximum allowable loading rate appears to be 22.4
t/ha/y. However, where the soil is characteristic of a
coarse sand, containing little or no silt or clay lenses, even
the 22.4 t/ha/y application rate could violate potable drinking
water standards. However, the application rates suggested are
based on contaminant levels directly beneath the application
plots. They do not reflect the possible dilution downgradient
18
-------
of the application plot from the natural diffusion and dispersion
of the contaminant in the groundwater. A buffer area between
the application .site and the nearest potable water source would
provide a chance for dilution to take place.
Acidification of the surface increments of mineral soil
was related to rate of sludge applied. This was not anticipated
since the Ca content of the sludge.was approximately 2.5%.
Apparently, liming, as well as K fertilization, is' needed on
sludge-treated land and should be related to the rate of sludge
applied.
Some movement of elements and changes of soil pH through the
profile of these sandy soils was apparent. These changes appear
to be within tolerable limits over the time of this study. No
increase in organic matter in the upper soil strata could be
measured with the techniques employed, however, increased dark
color in these soils was observed to correlate with the loading
rates. Lack of measurable increase in soil cation exchange
capacity may relate to the still relatively raw, coarse nature
of the organic matter of the sludge that entered the soil. Most
of the sludge remained on the soil surface.
Objective 4. To Determine the Effects of Wastewater Solids
Application on Land Productivity
Plant nutrients supplied by the stabilized domestic
sludge applied to the soil surface proved to be appreciable.
No deterimental effects of heavy metals on plant growth were
detected.
Both quantity and quality of plants produced were enhanced
by sludge applications. The elements, N, P, Ca, Mg, Cu, ~and Zn
usually increased in grasses with rate of sludge applied.
Yields of grasses were difficult to determine accurately
because of losses attributable to wildlife grazing. Loss
of plant production also occurred when sludge was applied when .
grass was so tall that lodging resulted and only the upper
leaves were harvested. Improperly timed applications also re-
duced the fertilizer efficiency of applied nutrients. Low K
supply in sludge undoubtedly limited plant production.
Although crop production with sludge application was
greatly increased, it is felt that the full soil amelioration
potential was not realized because the bulk of the sludge re-
mained on the surface. The surface application technique
was considered best for this short term study from the point
of view of maximizing volatilization loss of N compounds,
minimizing groundwater contamination, saving the cost of incor-
poration, and avoiding crop disturbance and soil erosion loss.
19
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The surface accumulation after 3 years of application was
appreciable (particularly at the highest loading rate) and could
be removed for sale as a soil amendment, or incorporated to
provide additional nutrients to crops and increase the nutrient
and moisture retention capacity of the soil. If accumulated
surface sludge is skimmed off for sale, there should be no need
to "rest" the site. If a 3-year accumulation is tilled in,
sufficient nutrients may be released to warrant cessation of
applications until the flush of nitrogen is dissipated.
It became apparent,.however, that there are many opportu-
nities to improve on the system of land application that was
employed in this study. To increase crop production and removal
of potential pollutants, coordination of applications and crops-
management must be maximized. Diversification of crops, par-
ticularly with regard to cool and warm season species would
facilitate application and would better utilize nutrient
elements in sludge and decrease groundwater contamination. The
major NOs breakthrough occurred in this study where the heaviest
rate was applied to the sandiest soil in the final year that had
the highest rainfall on record. This occurred in the season,
January through March, when there was little or no crop'growth.
Also, as much as 40% of the year's application had been made
after the last harvest of the major crop, Midland bermudagrass.
If, a non-dormant type cereal rye had been available, the break-
through should have been much reduced. Greater wildlife
utilization could have been realized if more cool season crops
had been available. Other studies indicate that the population
of denitrifying soil microorganisms increases with years of
manure added to the soil, so the wastewater solids application
rate that land could accommodate might increase with time.
Nitrifying inhibitors might be applied to reduce groundwater
contamination by nitrates.
Objective 5. To Determine the Effects of' Wastewater Solids
Applications on Native Vegetation and "Crop
Production
Both quantity and quality of plants produced were enhanced
by sludge applications. The elements N, P, Ca, Mg, Cu, and Zn
usually increased in grasses with rate of sludge applied.
Nitrogen and P contents of leaf tissue of several woody species
were increased significantly by sludge applications. Some
increase in K, Mg, Zn, Cu, and Pb was noted in these tissues.
Calcium and Mn actually decreased in foliage of woody species
treated with sludge. Wood species in native stands increased
in trunk or twig growth in response to sludge applications as
measured one and one half years after initiation of sludge
applications.
Yields of grasses were difficult to determine accurately
because of losses attributable to wildlife grazing. Loss of
20
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plant production also occurred when sludge was applied when
grass was so tall that lodging resulted and only the upper
leaves were harvested. Improperly timed applications also
reduced the fertilizer efficiency of applied nutrients. Low K
supply undoubtedly limited plant production.
Our data indicated that the sludge-stimulated crop of
Midland bermudagrass depleted soil moisture more rapidly than
the no-sludge crop. Crop production could have been increased
further and the land's capacity for waste disposal could have
been augmented if it were irrigated with effluent. This would
be a logical procedure if pipeline transport were available.
Alternately, irrigation from on-site wells would have been
beneficial from the point of view of increasing crop produc-
tion and increasing N-loss through denitrification. Liming
and K fertilization would then be mo're important.
Initially the 22.4 t/ha/y (.10 TA) rate did not appear to
supply sufficient nutrients for good crop production and N
deficiencies were evident on .the Midland bermudagrass. The
44.8 t/ha rate resulted in better production of grass, but the
89.6 t/ha did not appear to inhibit grass'growth even when
applied.to cool season perennial grasses so as to inundate the
grass in July. This is gross mismanagement but served to
illustrate crop tolerance. Crop injury developed when heavy
applications were made to grass that was tall enough to
harvest as a hay crop.
Objective 6. Tp_ Observe the Effects of_ Wastewater Solids
Applications on Wildlife Reactions
Elements reportedly toxic to animals didn't increase in
the plant tissues to presumed injurious levels. Animal
acceptance of sludge-treated grass was good, and a clearcut
preference by deer and rabbits was seen for grass treated with
the highest rate of sludge. Wildlife consumption of Kentucky
bluegrass and cereal rye 'in fall and spring and sudahgrass in
summer was appreciable. Deer and rabbits consumed little
Midland bermudagrass, but cattle readily ate it even when
obviously coated with, sludge.
In less than 24 hours after application, deer tracks were
observed over tire tracks of the applicator equipment, hence,
it was concluded that deer were not repelled by application of
fresh sludge.
Objective 7,
To Determine Any Air Pollution Effects in
Regard to Odor and Bacterial Aerosol Trans
mission During Solids Applications
Odors at the sludge disposal sites were moderate to slight
under most conditions as long as well digested sludge was used.
21
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The worst odors were appreciably less offensive than those
commonly associated with farm manures.
The maximum distances (panel medians) downwind from the
disposal sites at which members of two panels could still detect
any odor were 35 and 39 m (114 and 127 ft) immediately prior to
spraying on two different days. The comparable values during
and immediately after spraying were 156 and 202 m (512 and
661 ft). One especially sensitive panel member detected odors
from the site at a maximum distance of 219 m (718 ft).
The predominant odors at the sites appeared to be derived
directly from the sludge, rather than from its decomposition
at the site. This was reflected in the odor descriptions,
which included stale, earthy, musty, and moldy.
The major emphasis in odor control must be placed on the
prevention of odor formation. This includes the necessity for
using only well-digested sludge, as well as limiting the appli-
cation rate to prevent flooding and anaerobic conditions.
The potential for odor complaints may be further reduced
by providing a sufficient buffer zone between the site and
any unwilling receptors. A minimum distance of % km (% mile)
would appear desirable for the surface application method,
/
1
Aerosol Transmission
Sampling under the given field conditions and using the
total plate count on TGE Agar, it was difficult to demonstrate
statistical differences between samples.
Microbial aerosol concentrations "in the absence of fresh
spraying (before a daily application) were virtually identical
to the background counts observed prior to the first sludge
application, averaging 200 per cubic meter (5-7 per cubic
foot). This value is in keeping with counts reported in the
literature. Two exceptional days with very high counts pre-
sumably resulted from the sporulation of saprophytes growing
on the sludge plots.
At the edge of the plots, microbial aerosol concentra-
tions increased during spraying to an average value of 3,000
per cubic meter (.86 per cubic foot) . After spraying the counts
decreased rapidly, but were still elevated compared to the back-
ground readings (average, 490 per cubic meter or 14 per cubic
foot.
Averaging concentrations per cubic meter (per cubic foot)
during spraying increased to 410 (11.6) at 15 m (50 ft) and
190 (5.4) at 30 m (100 ft) downwind, but the 30 m reading could
22
-------
not be shown to be significantly different than the before
spraying "background" of 130 (3.7). Samples collected at these
distances 5-30 minutes after spraying had returned to back-
ground levels.
Concentrations in samples collected on top of the sludge
spraying apparatus, to which the operator was exposed, were,
similar to those collected during spraying at the edge of the
site, averaging 2,600 per cubic meter (73 per cubic foot).
Overall, the percentage of large particles (5mm) increased
slightly during spraying (70%) relative to before and after
spraying (63% each). Only about 9% of the particles were 1-2
mm in diameter, the size range of greatest deposition in the
alveoli, .
There is a need for a suitable indicator for microbial
aerosols produced by spray application of sewage sludge on land.
The potential for adverse effects from microbial aerosols
produced by the spray application of sewage sludge on land is
difficult to evaluate. Generally, concentrations appear to
diminish rapidly with distance, becoming only marginally higher
than background readings at 30 m (100 ft) under most conditions.
Sporulation of saprophytes on the sludge plots is still readily
discernible at 30 m. (100 ft) however, (1,700 counts per cubic
meter or 47 per cubic foot before spraying, down from 3,900 or
100 at 15 m (.50 ft}.].. Thus, an adequate buffer zone must be
considerably larger than 30 m (100 ft). Dispersal by migratory
animals, such as birds and insects, must also be considered.
Objective 8. To Recommend Monitoring Systems and Other
Restraints ¥ithin the Area of the Application
4.
Fences, barriers, or remoteness of site can protect
the public from exposure to sites where sludge is
applied to the soil,surface.
Groundwater movement should be determined prior to plot
layout.
Soil pH must be maintained above 6.5 by liming to mini-
mize movement of heavy metals.
The groundwater hydrology, area of application, loading
rate, and type of soil will determine the number of
monitoring wells which should be placed above, within
and downgradieiit of the application site to identify
and characterize potential groundwater contamination.
23
-------
5. Downgradient wells should be within 30.5 m (100 ft)
of the application site.
6. The ideal monitoring scheme should include both static
and dynamic sampling; i.e. , skim-type and profile samples
for static analysis of the groundwater system and pumped
samples to determine the dilution effects.
7. Thorough groundwater sampling should be conducted at
least four (4) times a year.
8. Groundwater analysis should include the following para-
meters whenever possible.
Total Coliforms
Total Dissolved Solids
Ammonia-nitrogen (NH^N)
Nitrate-nitrogen (N03-N)
Nitrate-nitrogen (N02-N)
Total Phosphate (PO^-P)
Orthophosphate (0-P04-P)
Alkalinity
Hardness
Total Organic Carbon (TOC)
Chloride (Cl)
Floride (F)
Metals (Hg, Zn, Mn, Fe, Mg,
Pb, Cd, Cu, Ni, Al)
Temperature
PH
Turbidity
LAS or Alkyl
Sulfates
Specific Conduct-
ance
Silica (SiOo)
Potassium (K)
Sodium (Na)
Calcium (Ca)
Sulfate (SC-4)
Boron (B),
24
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SECTION 3
RECOMMENDATIONS
1. Based upon conservative considerations (excluding dilution
and diffusion downgradient) data from wells located adjacent to
application areas warrant the following:
a. A loading of 22.4 t/ha/y (.10 T/A/yr) of municipal
digested wastewater solids is feasible for sandy
("Lakewood) nutrient deficient soils provided pH
control is practiced.
b. This loading may be increased to as much as 44.8
t/ha/y (20 T/A/yr} on soils containing sandy loam
(Woodmansie and Downer soils),.
2. To maximize crop yields sludge application should be sup-
plemented by potash (_K) additions.
3. Good crop management procedures can and will increase the
quality and quantity of plants produced. Further investiga-
tions of soil -management"techniques such as surface removal
and/or plowing of surface cake should be made.
4. Sludge applications immediately before harvesting grass
should be avoided to prevent inundating and contaminating the
crop.
5. Irrigation may be considered for -maximizing crop produc-
tion on sandy soils.
6. Rates of annual application of municipal digested solids
appear to be limited more by concern for groundwater quality
than for crop production. Heavy metal uptake by plants was
not a problem.
7. Because wildlife will consume sludge ammended crops read-
ily, measures such as fencing will be needed to protect such
growth areas should harvesting be contemplated.
8. If odors and aerosols are unacceptable outside of the dis-
posal site, a % mile wide buffer should be provided when sur-
face application of liquid digested sludge is planned.
25
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9. Monitoring should consider at a minimum the following:
a. Number and location of monitoring wells must be .
based on study of the hydrology, soil type, and
sludge loading rates.
b. Both static and dynamic sampling procedures.
c. Periodic groundwater sampling and complete sludge,
crop, soil, and water analyses.
26
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SECTION 4
SITE SELECTION FOR APPLICATION OF WASTEWATER SOLIDS
LOCATION AND DESCRIPTION
The wastewater solids utilization project comprises three
sites in the Pine Barren Region of Ocean County, New Jersey
(Figure 1). The Downer Soil site, at Colliers Mills, lies
about 1,158 m (3,800 ft) north of Colliers Mills in Jackson
Township (Figure 2). The Lakewood and Woodmansie Soil sites,
Webbs Mill sites 1 and 2, located about 24.13 km (15 mi) south
of Colliers Mills, lie within 762 m (.2,500 ft) of each other
in Lacey and Manchester Townships (Figure 3). The sites are
isolated from populated areas and lie within the boundaries of
land managed by the New Jersey State Division of Fish, Game and
Shell Fisheries,
The topography of the sites- is one of low relief typical
of the Coastal Plain. The Downer soil site, at Colliers Mills
is at an altitude between 42.7 and 45.7 m (.140 and 150 ft),
and slopes towards a marshy stream at an altitude of about 39.6
m (.130 ft) . The Lakewood and Woodmansie soil sites at Webbs
Mill are at an altitude between 38,1 and 44.2 m (.125 and 145 ft)
located in the interfluve between Webbs Mill Branch of Cedar
Creek and an unnamed tributary of Webbs Mill Branch. The con-
fluence of these shallow streams lies at an altitude of about
36.6 m (120 ft) and east of the sites. All three of the sites
are immediately east of the major drainage divide, separating
the Delaware River drainage from the Atlantic Ocean drainage,
(Figures 2, and 3).
The climate of the area is temperate. Long-term records
indicate an annual average temperature of 53°F (12°C) with pre-
cipitation of about 114,3 cm (45 in) at .Colliers Mills and
116,8 cm (46 in) at the Webbs Mill sites.
Evaporation and transpiration, or the losses of water to
the atmosphere from wetted surfaces or through plant processes,
are about 61.0 to 63.5 cm (24 to 25 in).
GEOLOGY
The sites are underlain by three different soil types
which occur extensively in the outer Coastal Plain region from
27
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41'
40°
41
40°
16
32
EXPLANATION
COLLIERS MILLS
STUDY AREA
WEBBS MILL
STUDY AREA
30 MILES
48 KILOMETERS
Figure 1. Map of New Jersey showing location of study areas.
28
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74°27'30"
4Q°C5'00
40°0 5'00
BASE FROM
U.S. GEOLOGICAL SURVEY
CASSVILE 1957 ls24,OOO
I ' 2
1000 0 -lOOO 200O 3000 400O 5OOO 6000 70OO FEET
ISO ' I KILOMETER
CONTOUR INTERVAL 10 FEET
DATUM IS MEAN SEA LEVEL
EXPLANATION
MILE
APPLICATION PLOT
•
CONTROL PLOT
DRAINAGE
DIVIDE BETWEEN '
ATLANTIC OCEAN AND
DELAWARE RIVER
l;igure 2. Location of Colliers Mills, Downer Site 1.
29
-------
39°52
52'30'
BASE FROM U.S. GEOLOGICAL SURVEY
WHITING 1957, WOODMANSIE 1957,
KESWICK GROVE 1957, AND
BROOKSVILLE 1957 1:24,000
74°22'30'
IOP-P.— _P IOOO__gOOO 3OOO 4OOO 5000 6000 7000 FEET
15 O I KILOMETER
I MILE
CONTOUR INTERVAL 10 FEET
DATUM IS MEAN SEA LEVEL
EXPLANATION
APPLICATION PLOT
•
CONTROL PLOT '
DRAINAGE DIVIDE
BETWEEN ATLANTIC
OCEAN AND DELAWARE
RIVER
J-'igure 3. Location of Webbs Mill, Lakewood Soil Site 1,
and Woodttiansie Soil Site 2.
30
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New York to North Carolina. At the Colliers Mills site, the
soil type belongs to the Downer Series. At the Webbs Mill sites
the soils belong to the Lakewood and Woodmansie series. In
general, the unconsolidated sedimentary formations beneath the
study areas ranges in age from Cretaceous to Holocene and
compose a sedimentary column several thousand feet thick. These
thick deposits consist of an alternating sequence of relatively
permeable beds of sand and gravel and less permeable layers -of
clay and silt (confining beds). This study, however, is con-
"cerned chiefly with the thin surficial sedimentary rock unit
named the Cohansey Sand. The Cohansey Sand has been described
in Ocean County as a characteristically yellowish-brown,
unfossiliferous, cross-stratified pebbly, illmenitic, fine-to
very coarse-grained quartz sand that is locally cemented with
iron oxide. White, dark gray, and red kaolinitic clays are in-
terbeded with the sands as laminae or lenses that may be as
much as 9.1 m £30 ft) thick. The overall thickness within the
county ranges from a feather edge along its western margin to
61 m (200 ft) in the southeastern part of Ocean .County.
At the study sites, the Cohansey Sand is the surface for-
mation. The thickness at the Colliers Mills site is about 15.2
m (.50 ft). The thickness is also the depth to the base of the
unconfined aquifer. At the Webbs Mill^sites the base of the
unconfined aquifer or the top of the first significant con-
fining layer is at a depth of about 28.6 m (.94 ft).
Data from more than 120 holes, drilled, augered and driven,
during this study indicate that the Cohansey Sand at these sites
is heterogeneous and the lithologic continuity of individual
layers is not traceable.
SOIL SERIES
Three soils, typical of Ocean County., New Jersey and the
coastal plains of the Mid-Atlantic states were selected for
sludge disposal studies. Soil of the Downer series represents
the best soil (jfor crop production) available in appreciable
quantities in the region under consideration. The Lakewood
series represents the most widespread soil type in this region.
The Woodmansie is identical to the Lakewood series in A horizon
but differs in having a clay development in the B horizon (Figs.4-6)
Specific descriptions are as follows:
Downer Series
The Downer series consists of well drained moderately sandy
soils. They form generally under a hardwood forest composed of
mostly oaks and hickories.
31
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A typical Downer profile consists of 35.6 to 45.7 cm of
sandy loam or loamy sand surface soil. The-subsoil is 25.4 to
45.7 cm of sandy loam. Clay content normally ranges from 10 to
15 percent and silt content ranges from 5 to 25 percent. The
Substratum from 76.2 to 152.4 cm is loamy sand. Part of the
substratum in places is gravelly loamy sand. The gravel is ;
dominantly rounded quartzose ranging up to 2.5 cm in diameter.
Downer soils are extremely acid to very strongly acid
throughout the profile, unless they have been limed. Perme-
ability is moderate or moderately rapid ranging from 1.5 to
15.2 cm per hour. The available water capacity is moderate
based on a depth to 152.4 cm though crop roots are not exten-
sive below the subsoil.
Organic matter content is generally low in most places.
Cation exchange capacity for Downer soils normally ranges from
4.5 to 6.0 in the surface soil, 2.. 0 to 5.0 in the subsoil, and
1.0 to 3.0 in the substratum.
Lakewood Series
Lakewood series consists of excessively drained very sandy
soils. They normally form under a coniferous forest composed
of mostly pitch or shortleaf pines.
A typical Lakewood profile has a bleached light gray sand
surface soil 20.3 cm thick. The subsoil is from 20.3 to 63.5
cm yellowish brown sand. The upper 2.5 or 5.0 cm in places
contains a dark accumulation of organic and iron compounds. The
substratum from 63.5 to 152.4 cm is sand. In parts -of the
research plots there was 3 to 4 percent of clay accumulation in
the subsoil over the content in the surface soil.
Lakewood soils are extremely acid or.very strongly acid
unless they have been limed. Permeability is rapid exceeding
15.5 cm per hours. The available water capacity is low. Or-
ganic matter content is very low. The cation exchange capacity
of Lakewood soils ranges from 0.2 to 1.0 in the surface soil,
0.5 to 1.0 in the subsoil, and 0.2 to .1.0 in the substratum.
Woodmansie Series
Woodmansie series consists of well drained moderately
sandy soils with a bleached gray surface soil that exceeds
17.8 cm in thickness. The soils normally form under a pitch
pine forest.
A typical Woodmansie profile has a light gray sand surface
soil 20.3 cm thick. The subsoil from 20.3 to 76.2 cm is com-
posed of sand in the upper one-third portion and sandy loam in
the lower two-thirds portion. The substratum from 76.2 to
32
-------
152.4 cm is stratified layers of sand and sandy loam in.places
containing 10 to 30 percent rounded quartzose gravel.
Woodmansie soils are extremely or very strongly acid. Per-
meability is moderate or moderately rapid ranging from 1.5 to
15.2 cm per hour. The controlling horizon is the subsoil. The
available water capacity to 101.6 cm is moderate or moderately
low. Organic matter content is low. The cation exchange capa-
city is 0.5 to 1.0 in the surface soil, 1.5 to 9.5 in the sub-
soil, and 0.1 to 3.0 in the substratum.
HYDROLOGY
The Cohansey Sand is part of an interdependent stream-
aquifer system in the New Jersey Coastal Plain. This deposit
constitutes the most widespread and permeable section of satu-
rated sand in the water-table aquifer throughout most of
southern New Jersey and receives all of its recharge directly
from precipitation. The infiltration capacity is high so that
overland flow is of short duration. Most, of the soils are
capable of accepting more than 160 cm (6.3 in) of water per
hour. Thus there is little likelihood that the Cohansey rejects
recharge from precipitation except where the water table is at
or near the surface. The porosity of the material is in the
range of 30 to 40 percent and the weighted average specific
yield of samples is in the order of 23 percent.
33
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10
2O
I
CUMULATIVE
30 40 50
PERCENT
60
I
70
100
10-
20 —
30-
40-
50-
60-
70-
Q.
UJ
O
110-
120-
I3O-
140-
ISO-
160-
170-
SAND
SILT
CLAY
\
\
\
\
\
\
Figure 4. Particle size distribution in the profile
of Downer Loamy Sand.
34
-------
0
10
I
20
30
i
CUMULATIVE PERCENT
40 50 60 70
80
100
10-
26-
30-
40-
50-
60-
7O-
E
o —
Q.
LJ —
Q
110-
120-
130-
140-
150-
160—
I7O—
SAND
SILT
CLAY
\
Figure 5. Particle size distribution in the profile
of Lakewood Sand.
35
-------
CUMULATIVE PERCENT
o
10 20 30 40 50 60 7O
I i I i i i i
80
I
100
10-
20-
30-
40-
50-
60-
70-
o _
X
o.
LU —
a
110-
120-
130-
140-
I5O-
160-
170—
SAND
SILT
CLAY
'
'\
Figure 6. Particle size distribution in the
profile of Woodmansie Sand.
36
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SECTION 5
APPLICATION SITES
NATIVE VEGETATION
The sites chosen for the land application of wastewater
solids were forested with vegetation typical of these soils.
The Downer loamy sand was dominated by white, black, and red
oaks' (Quercus alba, Q. velutina, and 6. rubra) with an under-
story of mountain laurel (Kalmia latifolia, huckleberry
(Gaylussacia spp., and blueberry (Vaccinium spp.). The Lake-
wood and Woodmansie sands were both dominated by small red and
black oaks and pitch pines (Pinus rigida). These soils also
had an understory of huckleberry (Gaylussacia spp.) making this
the one form of vegetation common to the forested (native veg-
etation) plots of the three soils of this study. A more defini-
tive description of vegetation of the pine barrens may be found
in Harlow and Harrar, 1968.
SITE SELECTION AND PLOT LAYOUT
A minimum number of five plots per site was established as
a project requirement. The size of each plot was also esta-
lished at 929m2 (10,000 ft2). The dimension, spacing, and
orientation of the plots at each site were determined on the
basis of the probable direction and an estimate of the velocity
of groundwater flow and. the probable path of included contami-
nants that may occur under each plot.
Plot dimensions of 15.2 x 61 m (50 x 2'00 ft) were deter-
mined to be reasonably .adequate. The long dimension of each
plot was set parallel to the direction of groundwater flow. The
spacing between plots was set at about 30.5 m (100 ft) and the
plots were oriented so that the convergence of the groundwater
flow paths under the downgradient from the plots would be elim-
inated or held to a minimum.
A bulldozer with raker teeth was used to clear access roads
to selected plot areas. Perimeters of plots to remain in native
vegetation were bulldozed to permit traffic by the applicator
tractor and trailer. Existing vegetation was cleared from
three quarter-acre (0.093 ha = 15.24 m x 60.96 m) plots of each
soil series on which grass was to be established. Although an
37
-------
attempt was made to minimize removal of surface soil, while re-
moving stumps and roots, most of^ the mull and forest litter and
approximately 5 to 10 cm of the surface mineral soil were re-
moved.
Some small stumps and large roots still remaining had to
be grubbed and removed by hand to facilitate machine operations.
The soil was then disked and dragged in several directions in
an attempt to produce a more uniform surface.
Half of the lime required to neutralize soil acidity was
applied as hydrated dolomitie (45% CaO plus 30% MgO equivalent).
On the Downer soil this was 1681 kg/ha total oxides of Ca and
Mg, and on the Woodmansie and Lakewood soils, 14101 kg/ha total
oxides. This first half was disked into the surface 10 cm.
Approximately 50% of the first year's quota of wastewater solids
was applied as slurry on the designated 22.4 t/ha/y plots,, and
as sand bed filter dried cake on the designated 44.8 and 89.6
t/ha/y plots. This was done in an attempt to increase the
moisture holding capacity in the plow layer of these droughty
soils and enhance the chances of successful establishment of the
Midland bermudagrass. After plowing to a mean depth of 20 cm
with a 71 cm disk-plow the remainder of the required lime was
applied and disked in as before. Cross disking smoothed the
field somewhat to permit marking rows on 76 cm centers.
CROP ESTABLISHMENT
The decision to use Midland bermudagrass as the chief
vegetative cover for the sites to receive the sewage sludge was
based on experiences locally and elsewhere as reported in the
literature. It appeared that a vegetative cover should be as
stable and uniform as possible during the course of the demon-
stration. A perennial grass, once established, would minimize
land preparation (therefore requiring less management, equip-
ment, and energy) and erosion potential. The grass should also
be adapted to sandy soils under consideration and tolerate
extremes of fertility rates. Local experiences indicated that
Midland bermudagrass would meet these criteria. This grass also
has produced higher yields than any other perennial forage ever
reported in the State of New Jersey. Bermudagrass has a rel-
atively deep root system and utilizes a great amount "of nitrogen.
Midland bermudagrass has been successfully double-cropped
with rye. The drilling of rye into the fall-dormant bermuda-
grass permitted a cool season crop to be taken from the same
area of land without jeopardizing the perennial bermudagrass.
Thus plant uptake of potential pollutants could be maximized
during both cool and warm season without tillage of its asso-
ciated hazards and expenditures. With multiple surface
applications of sludge, loss of nitrogen to the atmosphere would
be enhanced and the potential for groundwater pollution would
38
-------
be reduced.
Plot planting fresh Midland.bermudagrass.sprigs every
76 cm on ridges left by each tractor-tire-made row was initia-
ted on July 11, 1973, and continued for two weeks. At elevated
soil temperatures fresh planting material failed to the extent
that between 30-70% of certain plots had to be replanted. On
the heavier Downer soil, planted during rainy weather, no
replanting was necessary.
Plots measuring 3m x 9m were limed and planted in a similar
fashion adjacent to experimental plots. No sludge was applied
to these plots. Inorganic fertilizer, 5-4.4-8.3 (N-P-K) at
650.5 kg/ha was applied prior to planting and again the follow-
ing spring to sustain the Midland bermudagrass to serve as check
plots. .
LOADING RATES
To assess the effect of rate of sludge application on the
environment, solids loading rates of 22.4 t/ha/y, 44.8 t/ha/y,
and 89.6 t/ha/y were applied on the three cleared plots compris-
ing three soil types. A 44.8 t/ha/y loading rate was employed
on the "native vegetation plot".
WELLS AND WELL CODINGS
Each plot and well were coded in order to computerize all
data. The letters CM are used to denote the Colliers Mills
site while WM are used for the two Webbs Mill sites. Two digits
are placed after the letters. The first denotes the site, and
the second signifies the particular plot. Webbs Mill has two ,
sites, therefore, the digits 1 and 2 were used to denote the
Lakewood and Woodmansie sands respectively, while the following
digit denotes plots 1, 2, 3, 4, or 5.. For the Colliers Mills
site, only the number 1 was used because there was only one
type of soil at this location. The letters A, B, C, D, and E
were used to code the wells and profile samplers on or down-
gradient from each plot. For example, the following three (3),
coded wells or profile samplers can be translated as:
WM12A: Webbs Mill, Lakewood site, plot 2, Well A
WM24D: Webbs Mill, Woodmansie site, plot 4, Well
or profile sample D^
CM13C: Colliers Mills, Downer site, plot 3, Well
or profile sample C£
(Subscripts identify the sampling zone of the profile sampler)
The plot layout, distribution of the wells and equipment
and assigned plot loading rates are shown in Figures 7, 8,
and 9. . . • •
39
-------
I4A
22.4t
I3A
ISA
I3D«
I4D
I3E«
I2E
IID.
JIE
C Control Plot
48.8t Application Rate
44.8t/ha/y
•ISA Observation Well
• Profile Sampler
>»» R Water Level Recorder
Figure 7
4OO FE.ET
50
100
METERS
Colliers Mills (Downer Soil) Site showing dis-
tribution of wells and equipment in or near the
plots.
40
-------
I4E
C Control Plot
22.4t Application Rate
22.45/ha/y
• 13A Observation Well
. Profile Sampler
X. R Water Level Recorder
50
100
500 FEET
METERS
Figure 8. Webbs Mill (Lakewood Soil) Site 1 showing
distribution of wells and equipment in or
near the plots.
41
-------
C Control Plot
44.8t Application Rate
44.8t/ha/y
Observation Well
Profile Sampler
Water Level Recorder
Rain Gage
24A
R
• RG
24E
Figure 9.
500 FEET
50
100
METERS
Webbs Mill (Woodmansie Soil) Site 2, showing
distribution of wells and equipment in or near
the plots.
42
-------
GROUNDWATER MONITORING
Groundwater monitoring procedures were varied depending
upon the specific condition being studied. In general, samples
were collected after bailing or pumping a well at.least long
enough to evacuate the equivalent volume of water in the well
bore. This approach was used so that a fresh and representative
sample of -water from the aquifer would be obtained. The problem
encountered with this method was that bailing or pumping dis-
torts the flow field and the water moving to the artificial dis-
charge point converges at the point -in a three dimensional
pattern. Thus, if a contaminated zone was only a small part of
the aquifer, and lies entirely within the distorted flow field,
a severe dilution effect occurs in the discharge water. This
produces a non-representative sample of the water quality in
transit within the aquifer, particularly if the aquifer screened
contains stratified layers of varying permeability and strati-
fied layers of contaminants.
In this demonstration study, the collection of "represen-
tative" water samples of the aquifer was needed only to define
the background water quality prior to the application of the
sludge. Thereafter, the collection of samples was based on the
need to know when and where any contaminants reached the upper
part of the saturated zone under the treated plots, and the
subsequent migration both vertically and horizontally. To
obtain the least disturbance to the flow field extractions_of
only the quantity of water needed for laboratory analyses,
through a system of collection using a "skim" sampler, a "pro-
file" sampler and in places specific conductance monitors were
utilized.
Skim Sampling
The device used for "skim" sampling is shown in Figure 10.
The sampler was lowered slowly down the well into- the saturated
zone so as not to seriously disturb the relatively static con-
dition of the natural flow field about the well. The sampler
was submerged to the inlet holes and the water was permitted
to flow into the sampler from just below the water level sur-
face. The sampler is then withdrawn and the sample is 'poured
into standard containers.
Profile Sampling
The profile samplers consisted of a series of tubes spaced
in sealed multiple sand or pea gravel-packed compartments in a
screened well point which was driven to specific depths. This
installation permits the simultaneous collection of a number of
groundwater samples by a vacuum manifold from predetermined
depths in a single hole. (Figure 11). Sampling in this manner
permits the determination of the approximate thickness of any
43
-------
/
HAND LINE
PVC
SCREW CAP
DRILL INLET HOLES
PVC PIPE
.WEIGHTED CONE
Figure 10. Diagram of Skim Sampler,
44
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contaminated zone and the transient depth of maximum concentra-
tion. Such profiles collected at each of the plots adjacent to
the wells and downgradient from the plots indicate the progress
of contaminant movement and changes in concentration.
GROUNDWATER TABLE FLUCTUATIONS
Changes in aquifer storage as a result of recharge from
precipitation and discharge into surface streams are manifested
in the fluctuation of the water levels. The water level in the
Cohansey Sand is constantly changing in response to recharge
from precipitation as indicated in Figures 12-15 by a typical
hydrograph from an observation well and a precipitation graph
in the study area from 1973-1976. This pattern of natural
fluctuation can be considered typical for the Cohansey Sand.
The high water levels during May, June, and July 1975 reflect
above normal precipitation during that summer. The rise of the
water levels is in response to the recharge from precipitation.
The rise and decline of water levels can be considered as
pulses. Therefore, it can be assumed that any stratified con-
centration of contaminants in the unsaturated zone that lies
within the region of water-level fluctuation will enter the
groundwater system as pulses thereby'producing stratified con-
centration of contaminants in the groundwater system.
GROUNDWATER MOVEMENT '
The direction of groundwater flow in a homogeneous
granular porous material is defined by streamlines which are
perpendicular to the equipotential lines (lines connecting
points of equal head) in an aquifer. Streamlines give the
instantaneous flow pattern, which in general changes under non-
steady flow conditions. Consequently, the periodic mapping of
the groundwater surface is a prerequisite for defining the
lateral movement of groundwater and included contaminants. The
initial water table maps constructed at the beginning of the
project identified the general direction of groundwater move-
ment and the gradient of the surface and thus influenced the
orientation and spacing of the plots.
In the study area., water table maps were constructed for
each site for different times beginning in April, 1973. These
typical surfaces are shown in Figures 16-18.
The contours (equipotential lines) indicate the altitude
of the water table and the difference in altitude ;on the line
normal to the equipotential lines indicate the gradients. When
a conservative contaminant (chloride, or nitrate) reaches the
water table anywhere below the application plots, it will move,
under the existing gradient with the groundwater in a definable
flow path toward the stream. However, under changing conditions
of recharge, discharge, and gradients, the flow path directions
46
-------
PRECIPITATION, CM. DEPTH TO WATER, METERS
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WATER LEVEL CONTOUR
CONVERSION FACTOR: 1 FOOT - O.3048 METER
•HA 033 WELL
— AUGER HOLE
-. SAMPLER
•R V/ATER LEVEL RECORDER
•RG RAIN GAGE
•50
400FKT
"wWER
DOV/NEF) SITE COLLIERS MILLS
Figure 16. Water Table Map at Colliers Mills Site 1,
August 27, 1975.
51
-------
•ISA OBS Well
»-•<- Auger Hole
• Sampler
?—-^.
' «
500 FEET
50 100
METER
Lakewood Site - Webbs Mill
• R Water Level Recorder
- ~ 120.00 "-—
Water Level Contour
Conversion Factor: 1 foot - 0.3048 Meter
Figure 17. Water Table Map at Webbs Mill Site 1, July 9, 1974.
52
-------
»I3A OBS WELL
-*- AUGER HOLE
SAMPLER
«R WATER LEVEL RECORDER
I2O. OO
WATER LEVEL CONTOUR
CONVERSION FACTOR: I FOOT = 0.3048 METER
0
0
t (
50
i i
100
5OOFEET
METER
LAKEWOOD SITE WEBBS MILL
Figure 18. Water Table Map at Webbs Mill Site 1,
April 5, 1976.
53
-------
also change thus causing shifts in the direction of flow. This
variability of the natural flow field causes a spreading that is
apparently part of the dispersion mechanism. In order to deter-
mine the approximate amplitude of the apparent changes in flow
directions, streamlines were constructed so that they would pass
through the center of each plot for each condition illustrated
by the series of water table maps. It was found that the
apparent horizontal shift or change in direction of flow along
streamlines passing through the center of the plots ranged from
8 to 25 degrees.
In summation the horizontal angular shifts that occur under
variable recharge-discharge conditions may be a great factor in
dispersion. The identification of the zones of contamination in
a non-homogeneous groundwater system can be extremely difficult
unless sampling procedures are designed relative to the changing
flow directions and vertical lithologic variations.
GROUNDWATER VELOCITY-TRACER TESTS
The use of tracers to determine the direction and velocity
of. groundwater flow has been described by many investigators
and it is acknowledged that there are some serious drawbacks in
using artificially injected tracers because of the effects and
mixing behavior of the tracers with the fluid-solid system.
Nevertheless, tracer tests have been used in making reasonable
estimates of groundwater flow velocities in many areas.
In this study tracer tests were used for comparison with
other methods of aquifer testing to estimate the flow velocity
of included contaminants due to the land application of sludge.
The tracers used were sodium chloride and rhodamine B dye.
The arrangement and procedure of the tests were planned to
limit the time of travel of the tracer to a relatively short
period and distance. This was done to avoid, as much as
possible, the effects of changes in recharge-discharge condi-
tions that might occur during the tests. Likewise the method
of injection and withdrawal of samples was such that the flow
field was disturbed as little as possible.
Three injection points and three sampling points were
installed at each of the three sites with the injection points
at_a radius of 1.8 m (.6 ft) upgradient from the sampling points
(.Figure 19) , The holes were oriented in a direction estimated
to be parallel to the flow path as determined from the latest
water table maps and prevailing gradients. Of the three sodium
chloride and rhodamine B dye tests only one of each produced
useable results. The unsuccessful tests are attributed to
locating the sampling points outside the flow path containing
the injected tracers.
54
-------
s- .
O) +->
•»-> o
(O O)
Q
s °
Injection Points
Observation Well
Sampling Points
Figure 19. Sketch showing well distribution used
in Tracer Test.
5.5
-------
In the sodium chloride tracer test three one pound bags of
sodium chloride were emplaced at the water table through three
(3) augered holes.near well CM11E at the Colliers Mills site.
The salt bags were crushed with the hand auger to release the
salt into the flow path and sampling in the sand points, which
were screened 0.6 m (.2 ft) into the water table, was continued
for a period of 12 days (June 25 - July 8, 1975). The samples
were withdrawn from the sampling points by a hand vacuum pump
in only such quantities sufficient for analysis. The calculated
flow velocity for this test in the shallow part of the aquifer
.was found to be 0.3 m/g (1.1 ft/day). This velocity compares
with 0.47 m (1.5 ft/day) calculated by empirical means.
The same well sampling arrangement was used for the rhoda-
mine B dye tracer test near well WM25B at Webbs Mill site as
was used for the chloride test near well CM11E. The same sam-
pling procedure was followed for a period of 4-5 days (September
30 - November 14, 1975) and the determination of the concentra-
tion was by means of a Turner model 111 fluorometer in the lab-
oratory. The calculated longitudinal velocity in the shallow
part of the aquifer was about 0.19 m/d (0.62 ft/d). This vel-
ocity compares with 0.20 m/d (0.69 ft/d) calculated by empiri-
cal means.
56
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SECTION 6
WASTEWATER SOLIDS APPLICATIONS
SOURCE
The type of wastewater solids utilized in this demonstra-
tion project was anaerobically digested sludge. Digested sludge
results from the anaerobic microbial breakdown of fresh domestic
organic matter collected from primary sedimentation and of waste
sludge withdrawn from the secondary sewage treatment process.
At the inception of the study in May 1973, wastewater
solids were obtained from the South Lakewood Sewer Company
secondary treatment facility. Although it was the intention of
the investigation to utilize only liquid sludge (slurry), two
forms of wastewater solids were trucked from this facility:
a dried cake from sludge drying beds and a liquid sludge. In
order that the 1973 growing season would not be lost for
planting crops and grasses, approximately 40 percent of the
annual solids loading had to be applied before planting could
commence. Only through the supplemental use of cake could
the 40 t/Ha loading be applied in the short period of time remaining
in the 1973 growing season.
The liquid sludge trucked from Lakewood immediately brought
about an "odor problem" at the application sites. The condition
of Lakewood wastewater solids was found to be less than ideal;
i-e., the volatile solids content was too high for the sludge
to be characterized as a "well stabilized" digested 'sludge.
Analysis of the Lakewood digester showed poor volatile solids
destruction, a relatively high volatile acid content for
digested sludge, and a pH less than 7.0. As a result of the
failing digester, the Neptune Township Sewerage Authority,
.Neptune, New Jersey, was used as the source of wastewater solids
from late July 1973 until completion of three years of solids
application ending in October 1975.
CHARACTERISTICS
Analytical Methods and Procedures , •
All wastewater solids composite samples were analyzed for
21 chemical constituents (Table 5). However, before any of
57
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.the components of the cake and liquid sludge could be determined,
each sample had to undergo a six hour acid digestion (macro-
Kjeldahl digestion unit). This process is necessary to insure
complete solubilization of all inorganic solids constituents.
Upon completion of the acid digestion, each sample was then
analyzed for its individual components according to the
methods and procedures recommended in Standard Methods for the
Examination of Water and Wastewater.
Sludge Cake
Cake samples from the two Webbs Mill sites were composited
into one sample and a similar composite for Colliers Mills was
obtained for characterization. Since all the cake-from the same
Lakewood drying beds and preliminary tests showed little vari-
ability in total solids and total volatile solids content from
load to load, a large composite from each site was utilized to
obtain the "average" concentration. It should be noted that a
large percentage of .the cake was composed of sand. A large
portion of sand had been removed with the cake when it was
mechanically removed from the Lakewood sludge drying beds.
Additional sand was accumulated when cake was mechani.cally
transferred from standing piles at the application site to the
manure spreader. Therefore, the cake applications had to be
corrected for this excess of sand in order to approximate the
equivalent amount of .cake to liquid sludge on a dry weight
basis. This would insure that the proper loading rates of
wastewater solids was maintained..
Liquid Sludge
Liquid sludge samples were collected from each tank truck
load. It was assumed that the mixing conditions created when
loading the tank truck and during transportation to the appli-
cation site would be sufficient to keep the load homogeneous.
Therefore, the sample could be considered "representative".
For a comprehensive analysis, samples from 10 to 20-tanker
loads were composited, since constituents of each truck load
did not vary much in solids and volatile solids content.
Table 6 summarizes the "average" wastewater solids character-
istics for the cake, 1973 liquid sludge, 1974 liquid sludge,
1975 liquid sludge and for the three years of solids appli-
cation.
The towns ,of Lakewood and Neptune could be characterized
as growing communities with primarily "domestic" sewage. The
chemical concentrations of sludge constituents encompassed
ranges normally observed in the literature for "domestic"
sludge with the possible exceptions of relatively high concen-
trations of iron and total nitrogen. Zinc concentrations were
also typically high in a few of the tanker loads analyzed.
59
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60
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APPLICATION METHODS AND TECHNIQUE •
Introduction
The role of Rutger's Department of Biological and Agricul-
tural Engineering was to design, procure, assemble, and maintain
the required field equipment for the application of liquid sewage
sludge. Subsequent reassignments added topographic surveying and
mapping of the plots, supervision of land clearing and roadwork
with the cooperation of the New Jersey Division of Fish, Game and
Shellfisheries, transportation of sludge and maintaining records
regarding dates and rates of application. Assembly of compo-
nents, modifications of equipment and major repairs were done
in the Agricultural Engineering Shop in New Brunswick, N.J.
with the cooperation of the shop foreman and staff.
Transportation
The collection, transportation and application of sewage
sludge to the Ocean County Sewage Sludge Application Sites were.
conducted by a three-man crew administered through the Department
of Biological and Agricultural Engineering. The Department was
responsible for the transportation of sewage sludge approximately
50 miles from the Lakewood and Neptune plants to the sites,
transferral of the sludge from the highway tank trailer to the
application unit, application of the sludge to the plots and
collection of all sewage sludge samples. The equipment was also
maintained by the Department and moved six- to eight miles daily
for security. -
The equipment included a 1500 gallon field application
unit, an International Harvester 574 farm tractor, a 4-wheel
drive International Harvester 1% ton stake body truck with field
maintenance, sampling and sanitation equipment, a single axle
International Harvester highway tractor and a 3000-gallon high-
way tank trailer. Six 3000-gallon loads were transported and
applied weekly.
Methods and Techniques
A multipurpose field application unit was designed by the
Department of Biological and Agricultural Engineering, assembled
by Agway, Inc., and is shown in Figures 20 and 21. It has a
capacity of 1500 gallons, a 9-inch ribbon auger and three outlets
for discharge of sludge. A Gorman-Rupp Model 203A Pump Kit was
mounted on an extended platform at the rear of the applicator.
Two 12 ft long irrigation booms were mounted on the trailer tank
for spray irrigation to the experimental test plots. A Gorman-
Rupp high pressure one-inch nozzle was installed on a two-inch
manifold and used to spray-irrigate liquid sewage sludge on
natural vegetation plots with trees in excess of eight feet in
height. Both the irrigation boom and spray nozzle are presented
61
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in Figures 20 and 21.
The Sewage Sludge Applicator Unit performed satisfactorily
after several modifications to its design. The original unit
was not designed to support the additional weight of the pump
and pump engine within the gooseneck tongue and required the
addition of a hew two-wheel chassis. The engine and pump were
mounted on the rear of the chassis permitting sludge removal
from the rear discharge port. This new chassis design per-
formed satisfactorily and resulted in no further structural
problems. The unit was originally designed to use two spray
irrigation booms. Because of difficulty in regulating the
flow of sludge through each boom and increased problems with
maneuverability, one of the booms was subsequently removed.
The techniques of application which were evaluated as
part of this project include a high pressure spray boom type
distribution system and a high pressure nozzle spray gun.
These techniques were utilized to apply liquid sewage sludge
to two types of vegetative plots. The simulated spray irri-
gation applicator was used to apply liquid sludge uniformly
to 12 different grass plots at three rates of application.
The high pressure gun was used to spray-irrigate three natural
vegetation plots.
I
The simulated spray irrigation boom as shown in Figure 21
consisted of 12 ft long, four-inch diameter irrigation pipe with
one-inch diameter spray nozzles spaced at two feet intervals
along the boom. The boom was hinged to a frame mounted on the
side of the tank. By swinging the boom out over the plots,
while regulating the flow of sludge, the operator could apply
the liquid sludge as shown in Figure 21. Because of the low
solids concentration of the slurry and the design of the boom,
several passes over each plot were required to apply the correct
amount of sludge. Modifications in the application schedule were
sometimes required because of the time required in harvesting the
crops, the variable weather conditions, the planting of cool
season grasses, equipment maintenance, and availability of
sludge.
Natural vegetation sites were spray irrigated with a high
pressure nozzle gun. The gun was constructed of a two-inch
galvanized pipe reduced to a one-inch standard nozzle. From
a service road, the operator directed the spray stream into
the natural vegetation plots covering all of the vegetation of
eight feet and lower. The uniformity of application was solely
dependent upon the judgment of the two-man crew because access
to the sites was very restrictive.
The methods of application used in this project were de-
signed to simulate land application of liquid sewage sludge by
conventional spray irrigation. Therefore, the evaluation of
64
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equipment utilized in this project was never conducted. The
anticipated evaluation of equipment used for direct incorpora-
tion of sewage sludge was also not accomplished because of
changes in cropping programs and the unavailability of higher
solids content sludge.
LOADING AND DISTRIBUTION OF WASTEWATER SOLIDS.
Dried cake and liquid sludge were applied at the two Webbs
Mill sites (Lakewood and Woodmansie) and at the Colliers Mills
(Downer) location on all cleared 44.8 and 89.6 metric ton/
hectare/year experimental plots. However, only liquid sludge
was applied to the 22.4 metric ton and natural vegetation plots
at the three application sites. The cake was spread on
May 29-31, 1973 at the Webbs Mill sites and on June 11, 1973
at the Colliers Mills plots. The cake'was used as a supplement
to liquid sludge to insure a nutrient supply before the initial
planting of crops. No additional applications of cake were
spread following its initial use in the Spring of 1973.
As discussed in a previous section, it was observed that
the cake had accumulated a considerable amount of sand from the
sludge drying beds and from transfer piles at the application
site. Since the annual loadings were based on dried tons of
wastewater solids, it became necessary to estimate the dried
weight of cake, excluding sand, in order to equate the cake and
liquid sludge loadings to the cumulative solids loading.. This
value was determined by relating the total volatile solids con-
tent of the cake drying on the Lakewood sludge drying beds to
that of the cake applied to the application plots. Assuming ;
that the percent volatile solids content is constant for both
cakes, one can estimate the quantity of sand accumulated in the
field cake. In general, the cake did not supply as much
nitrogen, phosphorus and potassium as anticipated as compared
to the liquid sludge, due to the unexpected accumulation of
sand.
Liquid sludge was transported to the application site in
a 300Q gallon tank truck. The wastewater solids were then
transferred to a 1500 gallon field unit for application to
individual experimental plots.
A record of the total wastewater solids and individual
sludge constituents applied to each experimental plot was com-
piled to evaluate environmental impact of sludge constituents
with regard to the soil, vegetation and groundwater." Cumu-
lative pounds of sludge components (dry weight basis) for the
1973, 1974, and 1975 applications are tabulated. Based on the
designated annual tonnage (22.4, 44.8, and 89.6 t/ha/y) of
wastewater solids applied to respective experimental plots,
most plots were within a few percent of the design loadings.
65
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The data were tabulated and transformed to express the
metric loadings of wastewater solids and individual sludge con-
stituents for three years of solids application.
The total loadings of a few sludge constituents applied to
individual plots are very low, particularly mercury, cadmium,
chromium and nickel applied after three (3) years are 0.6, 5.1,
15.4, and 11.5 kg/ha respectively. From a simple quantitative
viewpoint, it would appear that the. low loadings of these
sludge constituents would cause no significant change or
"measurable" impact to the soil, vegetation or groundwater.
The loadings of all other constituents are at least an order
of magnitude greater than the above heavy metals. Therefore,
a "measurable change" or environmental impact can be detected
and evaluated in the soil-vegetation-groundwater system for all
sludge constituents except the trace elements - mercury,
cadmium, chromium, and nickel.
66
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SECTION 7
AGRONOMIC ASPECTS
GROWTH OF NATIVE VEGETATION . : • ''
Sewage sludge was sprayed on the native veg'eta'tion frorii a
manifold of three nozzles mounted on the field-spraying trailei1
at a height of 8 feet. This resulted in a rather: complete' ; ' :
coverage of all foliage beneath that height. This coverage ' :
appeared to be sufficient to effectively shut off photosynthesis
and cause an appreciable elevation in leaf temperature because
-of the albedo effect. Indeed, it was not uncommon to see
numerous leaves (primarily oak) which had been sludge covered
that became necrotic on the stem in mid-summer. Sludge appli-
cations were made to native vegetation plots three to six
times per year for the three year period. At times months
elapsed between applications. Rainfall usually removed the
sludge from the foliage readily. The duration of restricted
photosynthesis would be extremely variable and not necessarily
a discrete phenomenon. The foliage and stems of the low-
growing huckleberry bushes were frequently completely covered
by sludge, however, loss of such plants appeared to be at a
very low incidence.
Data reflecting the growth of native woody, species taken
in late 1974, after one and one-half seasons of sludge appli-
cation, indicate that the nutrient value of the sludge had a
positive effect that exceeded any detrimental effect (due to
toxicity from heavy metals and/or inhibition of photosynthesis)
on native vegetation.
Plot locations were selected at two sites in Ocean County
to include three soil types typical of the coastal plain and
Pine Barrens. At each location, 0.94 ha plots of native vege-
tation were designated to receive sludge applications. The
0.94 ha plots received 44.8 t/ha/y dry matter in 1973 and
1974, and responses were measured of the natural vegetation
to the sludge applications during and after the second year of
sludge induced growth, the summer of 1974, and the following
winter dormant period.
67
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Growth of Woody Species
Increment borer cores were taken from randomly selected
trees in sludge-treated plots and also in adjacent check areas.
Annual growth ring width of oak species showed an increase due
to sludge applications of the previous year on the Downer loamy
sand. The growth of scarlet oak in the control series was less
in 1974 than in 1973, but in the sludge-treated area ring width
growth increased in 1974. With only ten samples taken from each
test plot no statistically significant difference between means
of increment change could be proved by a "F" test of unpaired
samples.
When sections of twigs were taken from 25 randomly selected
oaks (.with trunk diameters of approximately 5 cm) from the
sludge-treated plot and also the surrounding native vegetation
on Lakewood sand, the increase in mean ring growth due to sludge
treatment was significant at the 5 percent level of probability.
When oaks were similarly sampled from Woodmansie^sand a
sludge induced increase in growth ring width was significant
at the 1 percent level of probability.
Cross-sections of main stems of huckleberry bushes, 25
from each test plot, on each of the three soils were similarly
measured. The positive response in ring width increase due to
sludge treatment was significant at the 5 percent level of
probability for plants on the Downer and Woodmansie site, and
at the 1 percent level for plants on Lakewood sand. The
foliage of sludge-treated huckleberry bushes was completely
covered with sludge after each spraying. The positive response
of these small plants to sludge treatment is somewhat more
surprising than is. the response of the taller oaks, some of
whose foliage would escape the temporary photosynthesis-
blocking treatment.
Insufficient numbers of pines were found on the site of
the Downer soil. On both the Lakewood and Woodmansie sand
sites increment borings were taken from 25 pitch pines in
sludge-treated and untreated areas. On both sites the increases
in growth ring width of pines due to sludge treatment were
significant at the 1 percent level of probability.
Some dead plants of all species were found within sludge-
treated and untreated plots at all three soil sites. The
incidence of injury did not appear to be different because of
sludge application. The re-sprouting from the base of oaks
in treated plots was readily consumed by wildlife.
68
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Results of Tissue Analyses of Native Species
The color of the foliage of native vegetation receiving
44.8 t/ha/y of sewage sludge was darker green than in.the same
species surrounding these plots. This was evident on all three
soil types in 1974 through 1976, The color change was typical
of a response to nitrogen fertilization. Data indicates a con-
sistent increase in the content of total Kjeldahl nitrogen for
the four native species sampled. . .
The foliage sample size did not prove adequate for total
Kjeldahl analyses on these species for all soils and all years.
Therefore statistical.analyses of the above data was not possi-
ble. Analyses of P, K, Ca, Mg, Zn, Cu, Mn, Ni, Pb, and Cr were
obtained for oak, huckleberry, and pine under all these condi-
tions, and the,data were subjected to analyses of variance.
Table 7 indicates that the foliage of all three plant species
growing in sludge treated plots contained significantly more
P than the no-sludge counterparts surrounding these plots. Only
the sludge-treated oak leaves contained significantly more K
than the no sludge checks. Calcium concentration was lower in
foliage of all three species, but significantly so only in
huckleberry.
No significant differences (at the 5% level of probability)
were observed in the content of Mg and the trace elements and
heavy metals in the foliage of these species. Mean values for
Zn, Cu, and Pb were higher for the sludge treatment of all three
species. The Mn and Cr contents were appreciably lower in oak
and huckleberry on plots that received sludge.
These soils were not limed. If they had been, the Ca and.
Mg contents of the tissue might have been higher and the heavy
metals might have been lower because of the latter's lower
solubility at higher soil pH. The observation previously cited,
viz, increased growth of native vegetation following sludge.
application, is consistent with the increased content of N, P,
and K in the foliage.
EFFECTS OF WASTEWATER SOLIDS APPLICATION ON CROPS
Plant Establishment
.Midland bermudagrass, newly planted on experimental" sites,
grew through applications of wastewater solids sprayed on the
surface at intervals varying from daily for three' consecutive
days to weeks without an application. A heavy initial applica-
tion, such as the 89.6 t/ha/y Downer plot received one month
after being planted in 1973, was equivalent to 288,960 1/ha of
sludge in three days. At a mean of 5.681 solids, 16.38 t/ha
of dry matter equivalent was applied. This was the equivalent
to a depth of liquid sludge averaging 96 mm/day for three days.
69
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While occasional leaves of bermudagrass were submerged by
the sludge, the technique of plantings on ridges between tractor
tire tracks prevented serious inundation of plants. Essentially
no leaf scorch or injury of any sort to the bermudagrass or other
volunteer plant species could be attributed to sludge appli-
cations.
Tomatoes .grew profusely after following initial applications
of sludge. They grew well, flowered, bore fruit, and showed
negligible evidence of injury from subsequent applications of
sludge sprayed over them.
Fall panicum (Panicum dichotomiflorum), a summer annual
grassy weed volunteered profusely on the 44.8 and 89.6 t/ha/y
plots that had received a portion of the first year's sludge
as filter-bed dried cake plowed-in prior to planting the Mid-
land bermudagrass. Apparently, this weed proliferated the
previous season on the sand-bed filter and dispersed large
quantities of seed over this sludge. Essentially none of this •:
weed appeared in any of the 22.4 t/ha/y plots nor in the -native ;:
vegetation plots both of which received 44.8 t/h'a/y of liquid •'-
sludge only.
In addrtion to the abundance of tomato and fall panicum
seedlings, there were watermelon, muskmelon, cucumbers, pea-
nuts, and citrus growing in the sludge treated plots. Common
weeds in these plots included common ragweed (Ambrosia
artemisiifolia) lambsquarter '(Cheriopo'dTurn album) , redroot pig-
weed (Amararithus retroflexus) , purslane (Portulaca oleracea) ,
smartweed (Polygorium pensyivanium) , crabgrass (Digitaria
sanguinalisj, black nightshade (Solarium nigrum), goosegrass
(Eleusine indica), and carpetweed (MoTTugo verticillata). ,
These plants were not found in surrounding areas that had not
received sludge, for these areas had only recently been cleared
of pine barrens forest that did not include these species.
The site of the Downer soil (at Colliers Mills) was near
a long-established paved road, and a pine barrens sedge (Carex
perisyl'yariica) , and pokeweed ('Phytolacca americana) volunteered
in both the treated plots and in the cleared margins.
The only plant that successfully competed with the Midland ".
bermudagrass following its establishment on sludge-treated plots
was fall panicum. Properly timed harvesting could favor the
development of Midland bermudagrass over the fall panicum, and
this weed would not jeopardize production of the.crop species.
Each fall, soon after the last harvest of bermudagrass
for the season, the plots .were,sown to common rye (Secale : ,
cereale). A grain drill was modified so that opening coulters
cut through the dormant sod of'bermudagrass and rye seed was
placed approximately 4 cm deep in rows 22 cm apart. At a
71
-------
seeding rate of 100 kg/ha rye emerged uniformally each year even
when drilled into freshly applied sludge or .when sludge was sub-
sequently applied over the seeding. A substantial crop of rye
would develop in early spring. Midland bermudagrass would re-
establish dominance after rye 'was harvested.
On July 17, 1976, 'Piper' sudangrass was sown at 50 kg/ha
with the same drill described above. Low rainfall following
seeding resulted in marginal stands of sudangrass, especially
where tillage was not employed.
Crop Production
Yield determination from the 0.093 hectare plots were made
by harvesting the grass with a commercial forage harvester hav-
ing a 1.8 m cutter bar. A full swath was taken from at least
one length of the plot (61 m); when yields were low two lengths
were harvested. Typically, about 50 kg of the chopped grass
was blown into the box body of a following truck where it was
collected and weighed. A subsample of approximately 500 gm
was taken from five locations in the pile and sealed in a
plastic bag until the wet weight of the sample was determined.
After attaining a .constant weight in a 70°C forced air dryer,
percent dry matter was calculated in order to determine plot
yield. A portion of this sample was ground through a 40 mesh
stainless steel screen for chemical analyses.
Yields from the no-sludge control plots (9m x 3m) were
determined by harvesting 8 m lengths with one of several sickel-
bar-mowers that cut a width slightly less than 1 m in width
calculating the exact area harvested, and applying data from
its samples, handled as above, to determine dry matter and
chemical analyses.
Marked and consistent,increases in yield of dry matter of
Midland bermudagrass occurred with increasing rates of sludge
applied during 1973, the year of establishment. It was noted
that green color of the grass was darker at the higher rates of
sludge application. The low rate actually appeared N deficient.
Yields are low, however, because (1) planting was two-months
late (due to the need to get stable background data from well
water samples), (2) height of cut had to be exceptionally high
to avoid rough-terrain damage to the field- chopper used in
harvesting, and (3) less than three quarters of the first year's
rate of sludge had been applied at the time of the first har-
vest.
The superior initial stand of Midland bermudagrass on
the Downer soil enabled an earlier harvest, and a second har-
vest the first year. Hence, substantially higher total yields
were obtained on the Downer soil than the Lakewood and
Woodmansie soils. Wildlife consumption of grass was negligible.
72
-------
The yields of rye harvested from the Downer plots In the
spring of 1974 were not proportionate to the intended rates of
application as shown in Table 8. .It can be calculated that
ratios of rates of application were approximately 1:1:2 rather
than the target ratios of 1:2:4. The fact that the high rate
plot received a depth of 4.62 cm sludge between March 13, 1974
and March 20, 1974 when the rye was just breaking dormancy may
account for its relatively low yield. The stand of rye in the
high rate plot appeared sparser but darker green than those in
other plots at the time of harvest.
Rye on Lakewood and Woodmansie soils was consumed com-
pletely by wildlife, and no estimates of yield were possible.
Yields of bermudagrass similarly did not relate directly
to stated rates of application. Sludge application records
indicate that rates applied did approximate target values. For
the first harvests of Midland bermudagrass in 1974 the timing
of applications was good in that they occurred largely after
the grass broke dormancy and well before harvest time. Yields
of all plots were good, but did not increase in proportion to
rate of sludge applied.
In the second harvest of Midland bermudagrass the inverse
relationship of yield to rate of sludge application seen in
Table 8 for the Lakewood soil is attributed to the fact that
too much sludge was applied too late. Lodging was excessive
in the high rate plots, yields were reduced, and the grass ,was
injured.
Yields of third harvests were limited by low temperatures.
It was imperative that grass be harvested in the fall to
facilitate drilling in the rye cover crop.
In 1975 rye was again harvested from the Downer soil plots,
as indicated in Table 9 but consumption by wildlife was total
on the Lakewood and Woodmansie soils. Rainfall was exception-
ally high, and yields of bermudagrass from plots receiving
the lowest rate of sludge (22,4 t/ha/y) were down slightly
lower than those-of the previous year. With the exception
of the Woodmansie soil, yields of plots of the highest sludge
rate (89,6 t/ha/y) were higher. The records of sludge applica-
tions and further calculations indicate that 40% of the year's
allocation was made after the last harvest. But the highest
yields obtained from these sludge plots, in a year with good
rainfall, was still far below expectations, being approximately
half that obtained from research plots receiving commercial
fertilizer.
No sludge was applied in 1976; the intent being to evaluate
the residual effects of the applications of the three previous
years. Table 10 Indicates that rye yields were appreciably
73
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lower than in previous years when some sludge was applied in the
spring. No increase in yield due to the highest sludge rate can
be seen, but the intensity of green color of the rye was im-
proved with increasing sludge rates. Deer grazing appeared to
increase with sludge application rate. This factor was not dis-
cernable the first year, unimportant the second year, but appre-
ciable the third year. Deer had found a source of food they
like and frequented the area more with time, eating more of the
rye in the heavily treated plot. The greater wildlife popula-
tion on the sites of the Lakewood and Woodmansie soils again
completely consumed all the rye from all of those plots.
Unlike previous years the Midland bermudagrass did not re-
cover. Winter killing was quite complete on the Lakewood and
Woodmansie soils, ,and very extensive on the Downer soil. Piper
sudangrass was drilled in as previously described and yields
were taken to measure residual effects of the sludge on all
sites. Again yields did not correlate well with sludge rate
applied. Some deer grazing of sudangrass could be detected in
plots on the Downer site, but grazing was so intense on the
Lakewood and Woodmansie soils as to require estimates of con-
sumption to adjust yields.
After the sudangrass was established, and much later than
.Midland bermudagrass normally appeared, the few surviving plants
of bermudagrass began to show a pattern of survival. Many more
plants survived on the Downer loamy sand than on the Lakewood
sand or the Woodmansie sand. . More bermudagrass' survived in
plots receiving lower sludge rates or were outside of the plots
receiving sludge than in those plots, and more bermudagrass
survived around obstacles where bermudagrass could not be
mowed readily and therefore was defoliated less frequently.
r-
It would appear therefore that survival of bermudagrass
was enhanced by a narrower N:K ratio and a better carbohydrate
status.
CHEMICAL CONTENTS OF PLANT TISSUES
Subsamples of'Midland bermudagrass taken from the large
groundwater monitored plots were analyzed for major, secondary,
and minor nutrient elements, as well as heavy metals. Sludge
contamination of foliage was apparent on certain samples, and
concentration of chemical elements proved to be elevated in
those instances. Where no sludge had been applied since last
harvest, exceptionally low values were obtained. Such condi-
tions resulted in major variations of these elements in samples
analyzed.
Variations in dry matter yield of harvested forage were
often major factors in determining quantities of elements '
removed for individual harvests on each of the three soils over
77
-------
the study period.
Although elemental composition of crops relate well to rate
of sludge applied, exceptions among certain heavy metals are
occasionally found. The amounts of nutrients removed by
cropping are small in comparison with amounts applied in sludge
and even with those remaining on the soil surface in the form
of dried sludge. Availability of residual nutrients to the last
crop, sudangfass, proved to be very low.
RESPONSE OF A COOL SEASON GRASS MIXTURE TO SLUDGE APPLICATIONS
Sludge was applied by spray-boom application (previously
described) to a mature stand of a mixture of cool-season per-
ennial grasses. The grasses had been established with conven-
tional techniques including liming and fertilizing by the New
Jersey Divis-ion of Fish, Game, and Shellfisheries on Lakewood
sand. In a randomized block design three replicates of 7.5 m
x 13.5 m plots were established to receive 0, 44.8, and 89.6
t/ha/y dry sludge matter equivalent usually from mid-March to
the end of October,, 1973, to 1975 inclusive. One replicate
was fenced to prevent grazing by deer. No harvests were re-
corded in 1973 but three were taken in 1974 and 1975, and one
in 1976 to evaluate residual effects. Yields were determined
by harvesting strips approximately 1 m wide through the center
of each plot and correcting for moisture content. Subsamples
were analyzed for elemental composition as previously described.
In November 1975, 2QQ kg K/ha from KC1 was applied to 2 m x 6 m
portions of each plot.
Yield Responses .
Evidence of grazing of these grasses by wildlife was par-
ticularly noticeable in the cool seasons as was reported for
other situations by Kalmbacher. Only during the warmer months
was grazing pressure reduced to the point where forage would
accumulate to permit harvesting of unfenced plots. Grazing
was most intense on plots receiving the highest ra;te of sludge,
and grazing increased annually as if more wildlife was utiliz-
ing the plots with each succeeding year. In the last year
(19761 the density of rabbit pellets was estimated at 100/mz
on a closely grazed plot that had received 89.6 t/ha/y for
3 years. Rabbit pellets far exceeded deer pellets. Rabbits,
but not deer, did enter the fenced area at times but the
fenced area was generally grazed less than unfenced plots.
Differential application of sludge, and hence grazing also
brought about changes in population of grass species in these
plots. Table 11 indicates that species not adapted to high
fertility and close grazing were being depleted from plots_
receiving higher rates of sludge. Kentucky bluegrass continued
78
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to increase and the tall fescue and orchardgrass decrease, under
high fertility and close grazing to the extent that in 1976 the
unfenced 89.6 t/ha/y plots were essentially devoid, of other
plants. 'During cool seasons in particular, and with .ample
moisture available, these plots resembled a good lawn.
A positive response to sludge application rate is seen in
terms of 1974 yield data in Table 12 particularly for the
fenced plots. Yields are not as high as they should be because
there was some grazing by rabbits even in fenced plots, and
timing of application of the sludge was not the .best. These
same trends are seen in yields of 1975 shown in Table 13.
Moisture was more abundant in 1975 and should have induced
better growth, but grazing by wildlife was increasing, and it
was suspected that potassium deficiency might also have been limiting
production.
Another harvest was made on May 28, 1976 to measure the
residual effects of sludge applications that were applied prior
to the previous fall, and to determine the response to supple-
mental potassium fertilization of the previous fall. Yields
increase only slightly because of previously applied sludge
except where potassium was supplemented at 200 kg/ha. Consis-
tent increases in yield due to potassium applications resulted.
The increase due to potassium is uniform where no sludge was
applied because grazing was minimal. Increases of 153 and
128% were no'ted where potassium treated plots were fenced.
Similar increases due to potassium were recorded in unfenced
plots where, by chance, grazing was not so intense.
The positive response of these cool season grasses to
surface applied sludge was impressive, but could have been
greater if potassium were supplemented earlier. Better timing
of application of sludge may have enhanced yields also.
However, one application of approximately 6 cm in mid-summer
merely retarded growth, but did not cause direct injury to
these grasses. Limiting the severity of defoliation might
have assured persistence of the taller, usually more productive,
tall fescue and orchardgrass.
*
Chemical Analyses of Cool Season Grasses
A single set of samples was taken for analyses from all
plots in 1973, while the first two harvests and all three
harvests were sampled and analyzed in 1974 and 1975, respec-
tively. Control plots without sludge are particularly low in
nitrogen content and crude protein, but as can be seen in
Table 14 the mean values of three replicates of samples from
plots receiving 44.8 t/ha/y are appreciably increased for every
harvest of the three year period. Increasing the rate of sludge
80
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to 89.6 t/ha/y increased the nitrogen content slightly above the
44.8 t/ha/y rate. A similar pattern of a greatly increased
content with the first increment and a moderate increase with
the second increment include Na, K, Fe, Mn, Zn and Ni (the ,.
latter especially so in the last year). Essentially no in-
crease was seen in Cd.and Pb contents of this grass tissue as
a result of rates of sludge applied.
The increase in heavy metal content of crops appears to be
within allowable limits as to phytotoxicity and mammalian
toxicityv The increases in nutrient content of this forage due
to sludge applications confirms the fertilizer value of the
sludge and should prove to be of appreciable practical signifi-
cance in the production of wildlife or livestock.
SOIL WATER
During 1974, while the second year's application of sewage
sludge was being surface-applied, measurements of soil water
were made on four occasions. Neutron probe access tubes were
installed according to standard procedures in the Lakewood sand
and water content was measured with a Troxler neutron sealer
and probe. Areas considered were those 1) planted to Midland
bermudagrass and treated with each of the three rates of
sludge, 2) planted to bermudagrass but receiving no sludge,
and 3) bare soil, no vegetation and no sludge. The latter two
types of plots were always located in close proximity to each
of the sludge-treated plots.
The data of July 17, 1974, in Figure 22 were taken three
days after a harvest and five days after 15 mm of rainfall.
At each level of sludge applied, moisture had been markedly
diminished from the entire soil profile by the sludge-stimu-
lated bermudagrass. Where the soil surface was kept bare
appreciably more moisture was detected at the intermediate and
greater depths,. The plots of bermudagrass that received no
sludge, and only a minimum of fertilization to assure survival,
had^an intermediate level of moisture left in the soil profile.
Obviously, the production of a vigorous crop of bermudagrass
required an appreciable withdrawal of moisture from the soil
profile.
Data taken 18 days after harvest .and six days after a rain-
fall of 71.5 mm showed somewhat less discrete moisture curves
due to type of cover and sludge rate. More moisture was re-
tained in the 0-305 mm depth zone where the heavy'rate of
sludge was applied. A less marked effect of this sort is
shown in Figure 23 for the intermediate sludge rate and is
essentially non-existent for the lowest sludge rate. At this
85
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time crop depletion of moisture was not paramount, but the sur-
face mulch effect of the sludge was a factor.
Soil moisture measurements taken five, days after a second
harvest of Midland bermudagrass and four days after a 31.3 mm
rain are shown in Figure 24 . Increasing the rate of sludge
applied to 80.6 t/ha/y resulted in more moisture retained in
the 0-304 mm depth of the profile than was evident at lower
rates or other covers. The lower moisture values for the above
treatment that are evident at the 610-762 mm depth may be a
result of the moisture depletion by the sludge-stimulated crop
that was not restored by the previous rain.
The- data in Figure 25 were taken 16 days after a rainfall
of 15 mm, and 36 days after the previous harvest. Mid-October
temperatures were limiting bermudagrass production and a modest
harvest was taken four days later. The bermudagrass from the
intermediate sludge rate depleted moisture from the 304 to 610 mm
depth. Moisture was high in the 0 to 304 mm depth zone under the
high sludge rate possibly due to the accumulation of a wet mulch
of sludge on this surface. In this same plot the bermudagrass
appeared to extract appreciable moisture resulting in decidedly
dryer soil in the 610 to 1219 mm depth.
On July 17, 1974, sludge applied at 44.8 t/ha to native
vegetation on Lakewood soil increased soil moisture to a depth
of just over 1 m, but beneath this point soil moisture was
somewhat lower than a comparable non-treated area. Later, on
July 31, 1974, the sludge-treated forest soil had higher soil
moisture contents to a depth of just under 1 m, and beyond this
depth soil moisture decreased. Similar trends with identical
breaking points, at a depth between 914 mm to 1067 mm, were re-
corded on September 10, 1974 and October 10, 1974. (See Table 16).
SOIL TEMPERATURE
Data in Table 15 show that temperatures of forested
Lakewood soil were appreciably lower than bare soil, and
bermudagrass covered soil (with or without treatment) from
the surface to a depth of 305 mm on July 10, 1974. Bare soil
was warmer through this profile than were plots of soil with
a bermudagrass cover. Increasing rates of surface applied
sludge to bermudagrass for 2 years tended to decrease soil
temperature especially through the first four increments of
profile depth at this date. Similarly, on July 31, 1974 the
surface application of sludge to Lakewood soil covered with
bermudagrass decreased soil temperatures to a depth of 305 mm.
Higher rates of sludge had no greater effects on soil temper-
atures than the lowest rate. The same was true on the last
date of measurement. The trend toward decreasing temperature
with increasing depth was greatest at the earliest date and
least at the latest date.
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SURFACE ACCUMULATION OF SLUDGE
The effects of three years application of sewage sludge on
the soil surface was measured by means of a soil sampling tube.
Depths to sludge-soil interface were measured for each sludge"
.rate on each soil, and in the lateral boom-sprayed portion of
each plot as well as the central manifold-sprayed portion. The
difference in appearance of the effects of these modes of appli-
cation can be seen. Equal, rates of application were supposed to
have been applied by each technique. No striped or row effects
could be detected along the plot margins at the time these
samples were taken.
The means of ten 2 cm diameter cores from each of the above
conditions are given in Table 17. In every comparison the
depth of accumulated sludge was less in the central portion of
the plots where sludge was sprayed by a manifold than were
applied by a boom along lateral edges. When strips were roto-
tilled across plots to a depth of 8 cm, the darker color of a
greater accumulation of surface.sludge along lateral edges
could be readily detected in each plot.
The mean depth of sludge is consistently greater on the
plots of L.akewood soil than those on the Woodmansie soil and
generally greater than those on the Downer soil. No explana-
tion for this can be offered at this time. The high sludge
rate plot (89.6 t/ha/y) on the Lakewood sand was the plot to
show highest groundwater contamination with nitrates.
Opportunities for loss by volatilization were greater for
the spray mode of application which covered plant and soil
surface more completely than did boom application. Hence,
greater accumulation of surface crust occurred under the half
of each field receiving boom-applied sludge.
Data in Table 18 illustrate the weight of sludge accumu-
lated on the surface of these plots as kg/ha. Note that accumu-
lated .sludge ranged from 22% of that applied over the three year
period to low rate plots to 13% for the high rate plots.
Greater losses of dry matter in high sludge rate plots could be
attributed to microbial activity. Conceivably, in the thickest
(4.6 cm) crust, aeration and .moisture conditions might have been
more often optimized for microbial decomposition than in
thinner crusts. Leaching and volatilization losses have also
been occurring. . •
QUANTITIES OF ELEMENTS REMAINING IN THE SLUDGE ON THE SOIL
SURFACE AFTER 3 YEARS OF APPLICATION
The dried surface crust or cake formed by multiple annual
applications of sludge during 1973-75 was sampled June 30, 1976
from each soil series. Samples were analyzed for total.content
93
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(rather than extractable or available) of 17 elements. The
volume of sludge on the soil surface was. determined on the basis
of sludge depths given in Table 19 and plot size. Weight of
sludge remaining on the soil surface was determined from an
estimated specific gravity of 0.34, times these volumes.
Of the major fertilizer nutrients remaining in the sludge,
N would appear ample for crop production, even at the lowest
rate (22.4 t/ha/y) of application, providing 1/5 or more of the
N were available to the next crop. Phophorus accumulated in
quantities far exceeding any other mineral element in the sludge
and would appear to be adequate for any crop even at low avail-
ability rates. Potassium did not accumulate in quantities
needed by crops, though it too reflects rates of sludge applied.
The secondary elements, Ca and Mg, were not retained in
large quantities in the surface sludge. Soil analyses data
elsewhere in this report show that these elements had indeed
moved into the upper soil profile.
Iron and aluminum also accumulated in considerable quanti-
ties. Heavy metal accumulations do not appear excessive.
Availability to plants and solubility and hence leachability
of all these elements are pH dependent; at near normal pH,
mobility is minimal.
EFFECTS OF SLUDGE ON SOIL PROFILES
Important to the interpretation of the soil profiles is the
fact that dolomitic hydrated lime was .incorporated into the sur-
face 0-20 cm (as previously described) of the plots planted to
Midland bermudagrass, including the controls but not the native
vegetation (N.V.) plots.
The pH of the surface 10 cm of mineral soil in the sludge-
treated plots decreased annually. Below 10 cm soil pH increased
annually to a depth of 50 and possibly 75 cm. Some of the de-
crease in surface pH may be attributed to leaching of the lime-
stone that was originally applied and incorporated to a depth
of 20 cm, but in view of the fact that a high lime sludge accum-
ulated on the surface, the decline of one unit between year 1
and year 3 is appreciable. The limestone incorporated initially
would not be expected to evoke an increase of one pH unit in 4
years at the 45 cm depth. The persistence of a high pH in the
10-20 cm depth undoubtedly reflects, in part, the original lime-
stone application.
The effect of rate of sludge application on pH throughout
the soil profile does not appear to .be consistent. The low pH
in the surface 0-10 cm and the high pH in the 10-20 cm depth
during the third year of application on Woodmansie sand con-
firm the trend. The nearly uniform pH of 4.5 throughout the
96
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97
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soil profile on the unlimed plot of native forest vegetation
indicates the lack of effect 44.8 kg/ha/y of sludge on soil pH.
All three soils were very similar in soil pH, particularly
in that portion of the profile in which limestone was incor-
porated.
Available soil phosphorus (P) (extractable by North Carolina
procedure) increased markedly with increasing rates of sludge
applied after three years, to a depth of 15 to 20 cm. The
appreciably lower P content in the 44.8 t/ha/y plots in native
vegetation (N.V.) as compared with the same rate of sludge
applied to bermudagrass may reflect the combined effects of the
filtering action of the forest floor litter, and the substan-
tially lower pH of the unlimed soil minimizing P availability.
Availability of P in all sludge-treated plots decreases
precipitously with depth to compare closely with the no-sludge
plot at a depth of 10-15 cm.
Similarly, a marked surface accumulation in P occurred
with time. At the highest rate of application this effect
extended 15 cm deep after 3 years of application on Woodmansie
sand. As might be expected, sludge applications increased the
content of available P of the two sand-textured soils to a
greater depth than in the loamy sand (Downer).
There appeared to be no effects of sludge treatment on
available soil potassium (K), and this constitutent appeared
to vary somewhat from year to year without any apparent
pattern. Throughout .most of the soil profile the fine-textured
Downer loamy sand had a slightly higher content of available K
(extractable by North Carolina procedure) than did the two
sands.
The level of
highest in the 10
plots after three
is seen above this
continues down to
increase in Ca in
appears to extend
extractable calcium (Ca) appears to be
to 20 cm depth of the lime and sludge-treated
years. No clear effect of rate of application
depth, but a consistent positive effect
about 50 cm. On a cumulative basis the
the soil profile due to sludge application
but decline with depth of 135 cm.
Rate of sludge application did not clearly affect the level
of available magnesium (Mg). Mg was highest at the 5 to 10 cm
depth for all treatments in Lakewood sand after 3 years. Note
that the Mg values for 44.8 g/ha/y on the native vegetation
(unlimed) were appreciably lower than for the same rate on the
limed bermudagrass plot. Much of the Mg in the grass plots
therefore came from the dolomitic limestone applied and
incorporated in the soil prior to planting the grass in 1973.
No cumulative effect or differences between soil series could «'.
98
-------
be detected.
The mobile nitrate (N03) ion showed gross differences
between years that most likely reflect temperature and precipita-
tion conditions just prior to sampling. Data after the second
year of application showed a generally positive effect of sludge
loading rate, particularly in the 0-10 cm depth. The consis-
tently low N03 values in the native vegetation plot may relate
to the suspension of the sludge above the sampled mineral soil
by the surface covering of forest litter. Samples taken after
3 years of sludge application show a slight elevation in N03 in
the IS to 75 cm depth. This was probably a temporary effect
reflecting particularly heavy loadings of sludge on this plot
at the end of the season just prior to sampling.
Values for soil ammonium proved to be variable but low. In
aerobic soil ammonia values should be negligible and any positive
values may well be an artifact of sample storage.
After the third year of application there was some evidence
of a rate-related accumulation of total Kjeldahl nitrogen (TKN)
in the surface (0-10 cm) of sludge-treated plots. Other data
indicate no differences of importance among soil types. There
was, however, a cumulative effect of sludge applications on TKN
in the 0 to 10 or 20 cm depths.
The organic matter content of the mineral soils showed little
if any increase due to sludge rates applied. The major difference
between the control and native vegetation in the 0-10 cm depth is
attributed to the fact that the former was cleared by a bulldozer,
and the latter had an appreciable accumulation of organic matter
above the mineral layer and some of this undoubtedly entered the
0-5 cm portion of the soil profile in ages past.
The cation exchange capacity values for sludge-treated plots
were only slightly increased at the 0-5 cm depth above those for
control plots. There were no meaningful.increases due to rate,
or years of application.
_Soil conductivity data proved extremely variable. There was
a slight trend toward accumulation of soluble salts during the
first 2 years of application, but a decrease in the third year.
The latter may be attributable to the exceptionally high rainfall
in 1975, the third year.
Rate of sludge application increased the DTPA extractable
zinc (Zn) in the 0-10 cm depth. The annual increase in avail-
able Zn at the high rate of sludge application was significant.
Soil series had no appreciable effect on Zn level.
Copper (Cu) like Zn was increased in proportion to rates of
sludge applied, particularly in the 0-5 cm depth. More DTPA
99
-------
extractable Cu was measured from a greater depth (10 cm) where
the highest rate of sludge, was applied. Similarly a strong
cumulative effect can be seen with time, especially in the 0-10
cm depth zone. Values for Cu were similar in all soil series.
Manganese (Mn), like Cu and Zn also increased in the surface
soil according to the sludge applications and the number of years
sludge was applied, particularly in the upper portion of the soil
profile. DTPA extractable Mn was notably higher in the 0-2.5 cm
layer of unlimed soil of the native vegetation than at the same
sludge rate on limed soil. This is consistent with the reported
greater solubility of this element in acid soils.
There was an increase in the DTPA extractable nickel (Ni)
in the 0-5 cm depth, due to rate and duration of sludge appli-
cations, but at a much lower rate than for Zn, Cu, and Mn. v .
The more acid soils under the native vegetation did not increase
the extractable Ni over that of the plot of limed soil
receiving a comparable rate of sludge. There was no effect of
soil series on extractable Ni.
There
increasing
cm depth.
the period
cation and
tude than
differ in
was some increase in DTPA extractable lead (Pb) with
rate of sludge application, particularly in the 0-10
There was an accumulation in the surface layers over
of years studied. Response to rate of sludge appli-
soil acidity appear to be of a lower order of magni-
the four previous elements. Soil series did not
extractable Pb.
After 3 years there was no consistent increase in DTPA
extractable cadmium (Cd) in the soil profile. There were
instances, however, where high Cd values appealed in the surface
0-10 cm. This was unusual and may have been caused by an
application of sludge high in Cd.
There were no significant increases in soil chromium (Cr)
due to sludge treatments.
Significant changes in extractable elements in the profiles
of the three soils studied appears to be related to soil pH.
Soil pH was obviously affected both by liming of plots (other
than the natural vegetation plots) and by sludge applications.
Analyses of variance of the results of soil test data
taken in 1975 were performed on each element previously dis-
cussed at ten depths; namely, 0-3, 3-5, 5-8, 8-10, 10-20, 20-30,
30-61, 61-91, 91-122, and 122-152 cm. The three soil series
were used as replicates. Significant differences due to rate
of sludge application were found for soil pH and six elements
at various depths in the soil profile.
100
-------
Surface soil pH was lower in plots that received high sludge
applications than it was in plots with lower application rates
or in control plots that receive no sludge. This effect was
significant at the 1% level of probability. From 20 to 60 cm
the pH of the zero sludge treatment is significantly lower than
certain sludge rates. Rate effect is not consistent throughout
the whole profile. Sludge appears to have raised the soil pH
above that of the no sludge check plots in the 10 to 60 cm
depth zone.
Statistically significant differences in extractable P
related to the rate of sludge application were found in the
upper four increments of the composite soil profile. These
increases in soil P were significant only to a depth of 10 cm.
The mean value of extractable calcium (Ca) in the composite
profile of the three soils was significantly increased by sludge.
Rates of sludge cause consistently proportionate increases in
soil Ca concentration only below the 30 cm depth. Soil calcium
in plots treated with sludge at this 89.6 t/ha/y rate was
significantly higher (at the 5% level of probability) than the
no sludge check plot at the greatest depth tested; 122 to 152
cm, indicating appreciable mobility of Ca.
Extractable Zn in the soil profile varies in proportion to
the rates that sludge was applied, particularly at the first
four depths sampled, to a depth of 10,cm. The increase in Zn
at the 30 to 61 cm depth, particularly for the zero sludge
treatment represents high native Zn in the Woodmansie sand at
this depth in the soil profile.
Each increment of sludge added increased significantly the
amount of extractable Cu in three of the upper soil increments.
High levels of Cu are not found beneath the plow depth. Some
sludge was plowed into the soil the first year.
Extractable Mn in the five surface increments was highly
correlated with rates of sludge-applied. Below plow depth
differences could not be proven.
Similarly, extractable Ni remained primarily in the upper
soil strata. As with Zn, the Ni concentration shows higher
peak values in the 30 to 60 cm depth for zero sludge treatment
than sludge treatments.
101
-------
SECTION 8
AEROSOLS AND ODORS
MICROBIAL AEROSOLS
The objectives of the microbial aerosol work were the determination
of 1) the size of the buffer zone required to insulate surrounding areas
from the biological aerosols generated at the sludge disposal sites;
and 2) the extent of employee exposure to these aerosols. For reasons
discussed later, more limited goals were pursued, namely: detection of
changes in plate counts from air samples taken at various distances
from the sites 1) before, during, and after spraying, and 2) in the
immediate vicinity of the site personnel, in the presence and
absence of spraying. The scientific literature was then
studied in a. partially successful attempt to use these findings
to address the original objectives to determine the need for
buffer zones and precautions needed to protect employees from
exposure to aerosols.
An aerosol consists of liquid and/or solid particles sus-
pended in air. Biological aerosols may then be defined as
biological contaminants occurring as solid or liquid particles
in the air. The term is usually applied to aerosols containing
viable microorganisms, either as individual particles or as
constituents of larger ones. Other biological materials of
interest, such as pollen or mold spores (when growth is not a
concern), are then referred to as aeroallergens. To avoid
confusion with other biological materials such as insects and_
insect parts, arachnids, seeds, and the like, the term microbio-
logical or microbial aerosol will be used here. Viruses,
bacteria, fungi, algae, and protozoa may all be found in micro-
biological aerosols. Of these, algal and protozoan aerosols
are generally of less interest than the other three groups.
There is a long and well-established tradition for the
use of indicator bacteria in monitoring the public health
significance of waters and wastewaters. Unfortunately, no
such tradition exists for digested sewage sludge. Use of the
same indicators (coliforms, fecal streptococci) is open to
question without additional research into their survival rates
during digestion, relative to potential pathogens. In assessing
microbiological aerosols derived from digested sludge, the
problem is even more difficult. Virtually no quantitative data
102
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is available even for the spray disposal of sewage effluents,
which has been practiced to a far greater extent. Viruses and
sporeforming bacteria and fungi might survive considerably
longer than the typical indicator under such conditions. On the
other hand, direct enumeration of pathogens is at least as im-
practical for sludge aerosols as it is for water or wastewater.
In fact, "no satisfactory method is now available" for sampling
of viruses in aerosols. In view of these considerations-, the
monitoring method reluctantly decided upon was the use of a
"total plate count" similar to that used in the past water arid
wastewater testing.
All sampling for microbiological aerosols, was performed
using two Andersen stacked-sieve cascading impactors. This
sampler has been recommended as a standard sampling device
by the International Aerobiology Symposium.
A major drawback of this sampler for this study is that
it is not capable of measuring changes in concentration of
viable particles over short periods of time. Rather, it gives
a_total^value for sampling over a given period (usually one
minute in our case). For this reason, some efforts were made to
utilize an Anderson viable monitor. This device consists of a
rotating drum with a nutritive agar surface. During sampling,
aerosols are deposited in a continuous spiral line giving
information on instantaneous changes in concentration. However,
under field conditions, satisfactory results were not obtained
and use of this sample was dropped.
On the other hand, the Andersen sampler provided a special
advantage over other sampling devices for this study because
it automatically segregated particles by size during collection.
The Andersen sampler is designed for use at a sampling
rate of 28.31 (1.0 cubic foot) per minute of air. Periodic
calibrations of the pumps used in sampling were made to assure
maintenance of this rate.
A standard plate count medium, tryptone glucose extract
agar (TGE) was used almost exclusively. This medium is capable
of supporting the growth of a wide variety of aerobic and
facultative bacteria, and some fungi. In a few cases, EMG agar
was used as a selective coliform medium. Exactly 27 ml of
sterile medium was aseptically placed in each specially stan-
dardized glass petri dish. The dishes had aluminum tops in
which absorbent pads were placed to prevent the condensation ,
of excess moisture.
After sampling, plates were rushed back to the laboratory
(1-3 hr) where they were immediately placed in a 35°C incubator.
Incubations were for 20-22 hr, after which colonies were counted
with the aid of a magnifying glass.
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The major factors of interest for this study were the changes
in plate counts with 1) spraying (versus non-spraying, and 2)
distance from the site. However, numerous other factors entered
into the experimental design: sampling duration, height of sam-
pling, use of different samplers, weather conditions, time and
day of sampling, and sampling site. These factors were provided
for in the design to the extent possible.
Sampling under the given field conditions and using the
total plate count on TGE agar, it was difficult to demonstrate
statistical differences between samples.
Microbial aerosol concentrations in the absence of spraying
were virtually identical with the background counts observed _
prior to the first sludge application, averaging 200 per cubic
meter (5.7 per cubic foot). This value is consistent with
counts reported in the literature. Two exceptional days with
very high counts presumably resulted from the sporulation of
saprophytes growing on the sludge plots.
At the edge of the plots, microbial aerosol concentration
increased during spraying to an average value of 3,000 per cubic
meter (86 per cubic foot). After spraying the counts decreased
rapidly, but were still elevated compared to the background
readings (average, 490 per cubic meter or 14 per cubic foot).
Average concentrations per cubic meter (per cubic foot)
during spraying increased to 410 (11.6) at 15m (50 ft) and
190 (5.4) at 30m (100 ft) downwind, but the 30m reading could
not be shown to be significantly different than the before
sampling "background" of 130 (3.7). Samples collected at these
distances had returned to background levels within 5 to 30
minutes after spraying. .
Concentrations in samples collected on top of the sludge
spraying apparatus, to which the operator was exposed, were
similar to those collected during spraying at the edge of the
site, averaging 2,600 per cubic meter (73 per cubic foot).
Overall, the percentage of large particles (^
increased slightly during spraying (70%) relative to before
and after spraying (631 each). Only about 91 of the particles
were l-2mm in diameter, the size range of greatest deposition
in the alveoli.
There is a need for the development of a suitable indicator
for microbial aerosols produced by spray application of sewage
sludge on land.
The potential adverse effects of microbial aerosols pro-
duced by the spray applications of sewage sludge on land is
difficult to evaluate. Generally, concentrations appear to
104 ,
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diminish rapidly with distance, becoming only marginally higher
than background readings at 30m (100 ft) under most conditions.
Spores from saprophytes on the sludge plots are still readily
discernable at 30m (100 ft), however, (1,700 counts per, cubic
meter or 47 per cubic foot before spraying, down from 3',900, or
110 at 15m). Thus an adequate buffer zone to insure against
exposure to some microbial aerosols must be considerably larger
than 30m (100 ft).
ODORS
The major objective of the odor study was to determine the
type and extent of odor problems encountered during the disposal
of digested sewage sludge by surface spraying on land. Recom-
mended control strategies for such odors were also considered.
Odor may be defined as that property of a substance which affects
the sense of smell.
While odors are often cited as the major cause of air
pollution complaints from the public, in many ways the field
of odor measurement and control is a primitive one. For
example, although there are several devices (ranging from the
extremely simple to the very complex) designed to aid in the
measurement of odors, there is generally only one instrument
available for making the final analysis -- the human nose.
Even the way in which odors are detected by the nose is not
firmly established. The observations that similar, chemicals
may have distinctly different, odors, and that very different
chemicals may have specific odor may result from the complex-
ity of the problems encountered.
Two basic characteristics of any odor are its quality and
quantity (strength). Odor quality may be measured simply by
rating it.on a scale of hedonic tone or pleasantness/unplea-
santness, or it may be described by comparison with other odors.
Classification schemes are not uncommon though many difficul-
ties may be associated with their use. One of the more recent
schemes includes seven primary odors from which all others are
said to be derived. Of course, the ultimate description of
odor quality would be listing of the chemical species involved
and their relative proportions; this is rarely possible.
The ultimate measure of odor quantity would be to,deter-
mine the concentrations of the individual odorants present,
once, they were identified -- although even this could be mis-
leading because of possible interactions among them. At the
other extreme, a simple rating scale of strength/weakness can
be used. The method most commonly employed involves dilution
of the odor to the point at which it is just barely detectable.
This point is called the threshold odor concentration. The
strength of a given odor sample is then reported as the number
of dilutions required to reach the odor threshold.
105
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The ultimate goal of odor control must be the prevention of
objectionable odors at the receptor site (i.e., the prevention
of air pollution). Achievement of this goal may be approached
by preventing (1) the formation of odors; (2) the release or
escape of any odors formed; (3) the transmission of odors to a
receptor; and (4) the detection of objectionable odors by the
receptor.
The greatest successes in odor control are achieved through
Approach #1, prevention of odor formation. Approach #4, although
sometimes successful, is the least desirable type of control.
It involves the use of chemicals to cover up or "mask" the unde-
sirable odor. Because of the subjective nature of odor prefer-
ence, however, virtually any odor strong enough to act as a
masking agent is likely to be objectionable to some people.
In rare cases it is possible to find a chemical with an odor
which will "counteract" the undesirable odor, causing both odors
to disappear. Even when this is possible, it is not necessarily
desirable, as it involves intentional addition (at some expense)
of chemicals to the air. The potential hazards of various
masking and counteracting agents are not well known, but may
pose more of a health threat than the odor causing gases.
Odor analysis was first attempted using a standard ASTM
dilution method. Hamilton gas-tight syringes, which consist
of glass barrels with teflon-sealed plungers and Luer-Lok
tips were used. This method proved unsatisfactory.
A backup method involved determination of the maximum dis-
tance downwind at which the odor was detectable. It should
be noted that this is essentially a dilution method, one in
which the natural environmental diffusion process is substi-
tuted for controlled dilution in a laboratory. Thus, while the
results obtained are' less controlled and therefore less precise,
they closely represent the type of information desired.
The first measurements of this type were performed by the
two individuals doing the preliminary bacteriological aerosol
work in the Spring of 1973. In 1975, different 5-6 member
panels were assembled to make more detailed observations.
Panelists were also asked to rate the odor on a hedonic
scale (pleasantness/unpleasantness) and to describe it, both in
their own words and by rating various descriptive words as to
their applicability. The first seven descriptive terms used
represent the primary odors from classification scheme.
In addition to these specific observations, information
was also gathered somewhat more informally by talking with
people visiting or working at the sludge disposal site.
106
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Wind speed and direction were measured using a portable
wind vane and cup anenometer (Science Associates, Inc., Prince-
ton, N.J.) mounted on a 1.8m (6 ft) pole. A sling psychrometer
(#12-7011, Bacharach Instrument Company, Pittsburgh, Pa.) was
used to measure air temperature and relative humidity.
.Odors at the sludge disposal sites were moderate to slight
under most conditions as long as well digested sludge was used.
The maximum distances (panel medians) downwind from the
disposal sites at which members of two panels could still detect
any odor were 35 and 39m (114 and 127 ft) immediately prior to
spraying on two different days. The comparable values during
and immediately after spraying were 156 and 219m (718 ft).
The predominant odors at the sites appeared to be derived
directly from the sludge, rather than from its decomposition
at the site. This was reflected in the odor descriptions,
which included stale, earthy, musty, and moldy.
The major emphasis in odor control must be placed on the
prevention of odor formation. This includes the necessity for
using only well digested sludge and applying it at low enough
rate to prevent flooding and anaerobic conditions.
The potential for odor complaints may be further reduced
by providing a sufficient buffer zone between the site and any
unwilling receptors. A minimum distance of %km (% mile) would
appear desirable.
107
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SECTION 9
GROUNDWATER QUALITY
INTRODUCTION: POLLUTION VS. CONTAMINATION
It is essential prior to .evaluation of land disposal, to
effectively understand the difference between contamination of
a groundwater and pollution of the groundwater.
The following distinction will be used for the discussion
in this report. Pollution will be defined in terms of violation
of a standard and/or in terms relating to the interference with
a desired use of a resource.
Contamination on the other hand relates to an increase in
a substance normally present or an addition of a substance not
normally present that would neither violate any existing stan-
dard nor interfere with the conventional use of the resource.
In the land disposal of an organic sludge, some impact
must be expected from the normal biological processes result-
ing from the further decomposition of the sludge mass. To
expect land disposal without some impact on groundwater quality,
is not consistent with a knowledge of basic environmental mech-
anisms which themselves make land disposal a feasible alter-
native.
Soils are dynamic bodies consisting of three phases - gas,
solid and liquid, that are always moving toward equilibrium
with the environment. Any manipulation of soils alters the
environment and may cause qualitative change in soil water.
Some contamination of soil water and usually groundwater is
inevitable when soil amendments are applied. Use of sludge
as a soil amendment should not contaminate groundwater enough
to pollute it and interfere with its desired use. It is imper-
ative, as we discuss groundwater quality violations resulting
from land utilization of sludge, that we keep in mind this
important distinction between contamination and pollution.
SAMPLING SCHEDULE AND ANALYSIS
Approximately one liter of groundwater was withdrawn and
analyzed for as many as 34 different chemical constituents.
The 34 chemical constituents analyzed are listed in Table 20.
108
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TABLE 20. GROUNDWATER MONITORING
Total Coliforms
Total Dissolved Solids
Ammonia-nitrogen (Mfy-N)
Nitrate-nitrogen (N03-N)
Nitrite-nitrogen (N02-N)
Total Phosphate (PO.-P)
Ortho-Phosphate (O-P04-P)
Alkalinity
Hardness'
Total Organic Carbon (TOC)
Chloride (Cl)
Fluoride (F)
Metals (Hg, Zn, Cr, Mn, Fe, Mg,
Pb, Cd, Cu, Ni, Al)
Temperature
pH
Turbidity
LAS or Alkyl Sulfates
Specific'Conductance
Silica (SO?)
Potassium (K)
Sodium (Na)
Calcium (Ca)
Sulfate (804)
Boron (B)
TABLE 21. MODIFIED GROUNDWATER ANALYSIS
Total Coliforms
Temperature
Total Organic Carbon (TOC)
Ortho-Phosphate (0-P04-P)
Nitrate-nitrogen
Chloride (Cl)
Specific Conductance
Manganese (Mg)
Calcium (Ca)
Hardness
Copper (Cu.)
Zinc (Zn)
Sulfate (S04)
109
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The "comprehensive analysis" of the 34 constituents was per-
formed at intervals of six weeks. At three weeks intervals or
after an appreciable rainfall, groundwater samples were also
withdrawn for a modified schedule of chemical analyses consis-
ting of 14 determinations set forth in Table 21. A total of 57
groundwater samples were taken from each observation well for
comprehensive or modified analyses over a period of three and
one-half years.
In order to evaluate sudden changes in groundwater quality,
the frequency of groundwater sampling was intensified (begin-
ning in December 1974) to include weekly samples from all obser-
vation wells. However, only two (2) chemical constituents were
analyzed -- nitrate-nitrogen and specific conductance.
The first sets of profile samples were not installed until
July-October 1974. Only occasional samples were taken for
analysis of specific conductance and chloride. However, after
June 1975, sampling was intensified to study stratified layers
of contaminants. The chemical analyses performed on each
profile sample included pH, specific conductance, chloride and
nitrate-nitrogen.
Although the application of wastewater solids was termi-
nated in November 1975 after three years of solids applications,
sampling was continued for an additional year through November
1976. The additional year was necessary to evaluate the impact
on groundwater quality for that third and final year of solids
application, as well as any cumulative effects that may occur
after three years of land spraying of wastewater solids.
Laboratory analyses were performed according to the
following references.
(1) Standard Metho'ds for the Examination of Water and
Wastewater, 1971.
(2) Collection and Analysis 'of Water Samples for Dis-
solved Minerals andGas, U.S. Geological Survey
Laboratory Manual, 1970.
(3) Metho'ds for Chemical Analysis of_ Water and Waste,
Environmental Protection Agency, 1974.
(4) Mercury Analysis Manual - Flameless Technique, Per-
kin-Elmer, 1972.
(5) Chemical Analysis for Water Quality, FWPCA, 1969.
110
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BASELINE GROUNDWATER QUALITY BEFORE WASTEWATER SOLIDS
APPLICATIONS
The average concentrations of 33 groundwater chemical
constituents are reported in Table 22 for the three (3) indivi-
dual wastew'ater solids application sites -- Downer, Lakewood,
Woodmansie. Table 22 also includes the range of concentration
observed for each constituent. The range and average values
reported (Table 22) represent a condensed summary of the data
compiled from the chemical analyses of numerous samples with-
drawn from observation wells at respective sites.
The groundwater quality before sludge application reported
for the Lakewood and Woodmansie sites was similar. At the
Downer site the average concentration of most chemical consti-
tuents was higher. For example, the total dissolved solids
baseline concentrations at the Lakewood and Woodmansie sites
was 26 mg/1; however, the average total dissolved solids con-
centration in groundwater samples withdrawn from the Downer
site was 30_mg/l. Most chemical constituents followed this
generalization; _i-.j3., chemical constituents in groundwater
samples from the Downer site are slightly greater in concen-
tration than those observed at the Lakewood and Woodmansie
application sites.
The background groundwater quality before solids applica-
tions can be characterized as having a total dissolved solids
concentration ranging from 12-82 mg/1 (average: 28 mg/1).
The groundwater contained only small quantities of common
salts -- C1-, S04=, Ca++, Mg++, Na+, K+; there also appeared
to be no coliforms. Total organic carbon levels ranged from
0.5 mg/1 to 4.0 mg/1. Low levels of N03-N were observed
varying up to 0.3 mg/1. Only trace concentrations of phos-
phate were found with one exception; one observation well at
the Downer site contained 0.92 mg/1 P04-P. In almost all
samples only trace concentrations of heavy metals were ob-
served, but a few samples did contain concentrations of metals
considerably above the reported average concentration in
Table 22: aluminum ranged as high as 2.2 mg/1; copper varied
up to 0.057 mg/1; zinc varied up to 0.383 mg/1 and nickel was
found to be as high as 0.036 mg/1. Lead, chromium, mercury
and cadmium were not detected. However, it should be assumed
that traces of these metals do exist, but at concentrations
below the sensitivity of the analytical procedure.
GROUNDWATER QUALITY AFTER THE APPLICATION OF WASTEWATER SOLIDS
Introduction
To assess the changes in groundwater quality from the
land application of wastewater solids, the concentrations of
monitored chemical constituents from skim and profile sampling
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of each observation well were compared over time to (1) consti-
tuent concentrations of control wells, (-2) background consti-
tuent concentrations and (3) constituent concentrations of other
observation wells in the study areas. The comparison was to
identify pertinent trends and qualitatively evaluate changes in
groundwater quality as related to the following factors:
(1) Concentrations of sludge related constituents into
the groundwater
(2) Wastewater solids loading rates
(3) Soil type
(4) Seasonal variations
(5) Rainfall
(6) Cumulative trends over four years
(7) Nitrate contamination
(8) Drinking water standards
Analysis of Trends in Groundwater Quality
The results from 34 chemical analyses performed on samples
collected over a four-year period (1973-1976) were tabulated to
express the range and average chemical constituent concentration
observed for all observation wells.
The more mobile anions and cations (Na+, Ca++, Mg++, CI~,
304= and NC>3) show measurable groundwater contamination above'
background and control levels. Heavy metals contamination of
the groundwater was generally not detectable, with the possible
exception of copper and zinc.
There appears to be no evidence of coliform contamination
in any well due to the application of wastewater solids. A few
samples did contain one to four coliforms at times inclusive
of the control plots. An August 8, 1973 sample from the control
well at Colliers Mills - Downer site registered so many coli-
forms that there were too many to count (TMTC) on the membrane
.filter.
i .Upon installation of the wells there was contamination
ifrom the solvent used to connect the PVC well casing. After a
•few flushings of the wells, baseline Total Organic Carbon (TOG)
(Concentrations stabilized between 0.0 and 3.0 mg/1. Total
•Organic Carbon concentrations .in almost all wells were periodi-
cally in excess of recorded baseline concentration -- ;peak
^concentrations of 24 mg/1 and 20 mg/1 were recorded for wells,
115
-------
CM 14B (22.4 t/ha/yr) and WM 21B (44.8 t/ha/yr - natural vege-
tation) respectively.
Groundwater samples for many of the observation wells
showed little or no change in any chemical constituent concen-
tration, but in other wells, peak concentrations of many con-
stituents had increased by more than two (2) orders of magni-
tude from reported baseline levels. A closer examination will
show that in all but a few test wells located outside the plots,
the concentration of most chemical constituents analyzed ex-
ceeded background levels. The magnitude of contamination above
the recorded baseline values was dependent on the loading rate,
soil type, and type of vegetation. '
The concentration of a chemical constituent within an ob-
servation well was dependent on the location of the well with
respect to the direction of groundwater flow and whether the
wells were located within or downgradient of the application
site. Those wells designated as 'A', 'B', and 'C1 were within
the point of application while the 'D' and 'E' wells were
30.5m (100 ft) and 61m (200 ft) downgradient of the application
plots, respectively. While Wells A-G were within an application
plot, it would be noted that Well 'A' was installed on the up-
gradient fringe of the plot, Well 'B1 was in the center, and
Well 'C1 was installed at the far downgradient fringe of_the
application plot. One would expect little or no change in
groundwater quality for Well 'A' because uncontaminated ground-
water upgradient of the plot is always flowing through this
well. The data seem to support this generalization. Therefore,
the evaluation of groundwater quality from the application of
wastewater solid (breakthrough) is best interpreted from the
data obtained from Wells 'B1 and 'C1. Concentrations of
chemical constituents in Wells TB' and 'C1 within the same plot
can also vary significantly due to the nonhomogeneity of soil;
e_.£., a clay lens and the boundaries of the contaminate plume.
The TD' and '£' wells were installed downgradient of the
application site, according to the original water table maps
determined at the beginning of the study in 1973. However, it
was found that a change in direction of flow occurs under
changing conditions of flow gradients, recharge and discharge.
The concentration of chemical constituents, reported for these
wells can tend to become distorted due to changing flow direc-
tion. As a result, the values reported may be considerably
lower than the representative concentration which lies directly
along the mean line of flow. Additional skim samples with-
drawn from downgradient wells are also somewhat diluted because
these wells are not subject to vertical breakthrough of sludge
related chemical constituents, but are still subject to ground-
water recharge; hence dilution.
116
-------
Breakthrough of Sludge-Related Constituents into the Groundwater
The change in chemical concentration beneath the plot
specifically refer to the 'B' and 'C1 observation wells directly
on an application plot. In general, a change in groundwater1-
quality over time was easily seen in the fluctuation of specific
conductivity and nitrate-nitrogen in the groundwater. A typical
response curve for specific conductance versus time for a con-
taminated well, WM 13B (Lakewood 89.6 t/ha/y), is shown in
Figure 26. Figure 26 shows an increasing stepwise response
beginning early in 1974, increasing in 1975 and gradually level-
ing off during 1976. Figure 27 shows a similar response for
nitrate-nitrogen for this well. Additional curves showing
cyclic patterns in response to seasonal recharge are shown for
WM12B, WM24B (Figure 28) and CM13B, CM13E (Figure 29).
Figure 29 also shows the cyclic downgradient movement. The
first nitrate peak at well CM13B occurs on April 6, 1976;
whereas, the first peak at well CM13E, which is about 300 feet
downgradient from CM13B, occurs.on October 31, 1975, a time lag
of about 7 months (208 days). A calculation based on these
data indicate that the contaminant flow velocity is about
1.4 ft/d, which is comparable to velocities of 1.5 ft/d and
1.1 ft/d as determined by other tests at Colliers Mills. The
small reduction in nitrate-nitrogen concentration which took
place over the ,distance traveled, may indicate a contaminant
slug was maintained for this distance.
The breakthrough of sludge-related constituents above
baseline and control concentrations was initially observed at
the end of the first year of solids application, November and
December 1973. Analysis of groundwater constituents beneath
most plots showed an increase in dissolved salt concentrations,
particularly nitrate, sulfate, chloride, sodium, calcium and
magnesium. There was no breakthrough of coliforms, phosphates
and heavy metals.
Contamination occurred in slugs. For example, nitrate-
nitrogen breakthrough concentrations of 2.1, 3.52, and 2.5 mg/1
occurred on November 6, 1973 in groundwater samples beneath
plots WM14, WM13, and WM23 respectively, while the control wells
showed a NC^-N concentration of less than 0.1 mg/1. Contaminant
concentration had also increased sharply between December 11,
1973 and January 16, 1974, specifically beneath plots WM24,
CM12, WM12, CM11, CM13, WM13, and WM23. Nitrate-nitrogen
beneath the same plots had also increased from 1.3 to 21.2 mg/1
and 1.52 to 18.9 mg/1, respectively. Similar responses were
reported for chloride, sulfate, specific conductivity and
sodium during this period.
Analysis of groundwater samples taken in 1974 showed con-
taminant levels had increased above the concentrations reported
for late November and December 1973, particularly during the
117
-------
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WEBBS MILL LAKEWOOD SOIL
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1976
Figure 28. Cyclic fluctuations of specific conductances
in groundwater at Webbs Mill.
120
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Figure 29. Cyclic fluctuations of Nitrate-Nitrogen at
'Colliers Mills Wells CM13B and CM13E.
121
-------
months of January, April }j August, October, and late December.
The concentrations of the more mobile sludge-related constituents
indicate that contamination above background levels had occurred
beneath all plots by early 1974;- however, contaminant levels at
each plot varied according to plot loading rate and soil type.
There appeared to be no breakthrough of coliforms, phosphates or
heavy metals. In general, the magnitude of contaminant leaching
through 1974 appeared to be greatest beneath the following plots:
CM13, WM12, CM23, WM21, and WM24.
One of the largest slugs of sludge-related constituents to
enter the groundwater occurred in late December 1974. The
period between December 1, 1974 and January 19, 1975 indicated
a large increase in contaminant concentrations beneath almost
all plots, independent of loading or soil type. The 44.8 t/ha/y
natural vegetation plots (CM11, WM11, WM21) and the 89.6 t/ha/y
plots (CM13, WM13, and WM23) appeared to have the greatest
increase in groundwater contamination. For example, beneath
the WM21 plot, sulfate concentrations increased from 17 to 133
mg/1, nitrate-nitrogen levels increased from 9.9 to 14.1 ing/ 1,
chloride increased from 21 to 366 mg/1 and total hardness levels
increased from 8.9 to 172 mg/1 (as
Results for 1975, a record wet year, groundwater samples
also revealed that large slugs of contaminants had entered the
groundwater during January, April, June, September and October.
Contaminant concentrations were also considerably greater than
the values reported in 1973 and 1974. Concentrations of\the
more mobile sludge-related constituents were above baseline and
control levels beneath all plots, while breakthroughs of phos-
phate and coliforms were not found. Concentrations of heavy
metals, especially copper and zinc, also showed a slight
increase above baseline levels beneath the WM13 (Lakewood -
89.6 t/ha/y) and WM21 (Woodmansie - 44.8 t/ha/y) plots.
Of particular interest is the contaminant breakthrough that
occurred during September and October 1975, a significant re-
charge period. The sudden increases in nitrate-nitrogen,
specific conductance, chloride, sodium and total hardness from
September 19, 1975 to October 31, 1975 indicate the transport
of a large slug of contaminants into the groundwater. The data
indicate that there was little contaminant concentrations change
beneath the 22.4 t/ha/y plots during the period, while plots
receiving a 44.8 t/ha/y and 89.6 t/ha/y had a very large
increase in concentration of many sludge-related constituents.
The sulfate concentrations increased from 40 to 100 mg/1 be-
neath the CM12 plot, from 70 to 200 mg/1 beneath the WM21
plot, and from 140 to 250 mg/1 beneath the CM13 plot. Nitrate-
nitrogen concentrations also increased sharply beneath these
plots, 33.6 to 66 mg/lm 22.3 to 65 mg/1, and 11.6 to 84 mg/1,
respectively.
122
-------
Leaching occurred in all plots in January, February and
April of 1976. The average contaminant concentration was gener-
ally equivalent or less than the levels reported in 1975; but,
the average contaminant concentrations did appear to increase
beneath the Lakewood WM12 (44.8 t/ha/y) and WM13 (89.6 t/ha/y)
plots. There was no breakthrough of phosphates or coliforms;
however, heavy metal concentrations, specifically copper and
zinc, were again above background levels beneath the WM13
(Lakewood - 89.6 t/ha/y) and WM21 (Woodmansie - natural
vegetation).
The vertical distribution of nitrate-nitrogen may illus-
trate the nitrate-nitrogen buildup in groundwater from sludge
application. The highest concentration of nitrate-nitrogen at
the 89.6 t/ha/y plot did not occur at the water table,, but at
a depth within the plume. Nitrate-nitrogen concentration ranges
from about 100 mg/1 within the plume to less than 10 mg/1 at a ,
depth of about 20 feet below the water table.
The vertical nitrate-nitrogen concentration distribution
resulting from a 44.8 t/ha/y application rate on August 2, 1976
ranged from about 36 mg/1 at the water table to less than 1.0
mg/1 at a depth of about 9 feet below the water table. The
nitrate-nitrogen concentration distribution resulting from a
22.4 t/ha/y application rate on September 24, 1976 ranged from
about 20 mg/1 within the plume to about 0.10 mg/1 at a depth
of about 8 feet below the water table.
The difference in vertical distribution pattern, where the
higher concentration of contaminants are at the water table on
August 2 and below the water table in September and October can
be attributed to the cyclic pattern of movement of the contami-
nants in response to recharge. On August 2, 1976, the trough
of the cycle had not been reached and the higher contaminant
concentration was still at the water table. By September 24,
1976 the low point of the cycle had occurred and the higher
contaminant concentration had moved deeper into the saturated
zone.
In the next recharge period in the late fall and winter of
1976 and early 1977, the cyclic change in the concentration of
nitrate-nitrogen should again occur.
Effects of Loading Rates on Groundwater Contamination
As discussed in previous s-ections, each site consisted of
five plots; three plots were cleared of all natural vegetation,
in order to plant Midland bermudagrass and cool season rye
grass. Another plot remained in its natural state, while the
fifth plot served as a "control". The wastewater solids
loading rates selected were as follows:
123
-------
(1) 22.4 t/ha/y
(2) 44.8 t/ha/y
(3) 44.8 t/ha/y - natural vegetation plot
. (4) 89.6 t/ha/y
(5) Control - no wastewater solids applications
Groundwater contamination was observed beneath all plots
receiving wastewater solids applications. Contaminant con-
centrations of most sludge-related constituents generally
increased with increasing loading rates beneath the cleared
plots. This was particularly true at the Colliers Mills-
Downer and Webbs Mill-Lakewood locations.
It should be noted that this discussion pertaining to the
44.8 t/ha/y wastewater solids application rate is limited to
the three cleared 44.8 t/ha/y plots. The 44.8 t/ha/y natural
vegetation plots were not discussed in this section because
plot characteristics were significantly different than that
of a cleared plot. The cleared plots were limed, the natural
organic layer was removed, and cover crops were planted and
harvested, while the natural vegetation plot remained in its
"natural state".
Although groundwater contamination increased with in-
creasing loading rates at the Downer and Lakewood sites,
groundwater quality at the Webbs Mill site on Woodmansie
soils did not substantiate this trend. Groundwater contam-
ination was greater at a wastewater solids loading rate of
22.4 t/ha/y than that of the larger 44.8 t/ha/y loading rate.
Average contaminant levels beneath the 22.4 t/ha/y were al-
most equivalent to the results reported at the Woodmansie
89.6 t/ha/y. These observations would suggest a 22.4 t/ha/y
wastewater solids loading could have more adverse impact on
groundwater quality than the larger 44.8 t/ha/y solids load-
ing. Although groundwater quality data at the Woodmansie
location support this anomalous observation, it can be ex-
plained by the non-homogeneity of the soil. The original
well driller's log indicates a possible pocket of sand on
the Woodmansie 22.4 t/ha/y plot in the area of the 'B' well.
The sand pocket is not characteristic of a Woodmansie soil,
which has more silt and clay development. However, the sandy
soil pocket would account for the large peak and average con-
taminant breakthrough concentrations observed on this 22.4
t/ha/y plot. Therefore, the groundwater quality data re-
ported for the 'B' well on the Woodmansie 22.4 t/ha/y plot
could be considered "atypical" of a Woodmansie soil and was
not included in the development of any conclusions pertaining
to the Woodmansie soil.
Groundwater contamination was observed beneath all
cleared application plots, independent of loading rates. How-
ever, the magnitude of groundwater contamination above back-
124
-------
ground levels for .most sludge-related constituents generally
increase proportionally with increasing wastewater solids
loadings.
Effects of Soil Type on Transmission of Contaminants into '
Groundwater
Wastewater solids were distributed to three separate appli-
cation sites, each having a different soil - Downer series,
Lakewood series, and Woodmansie series.
It should be noted that the following discussion pertains
only to the cleared plots. No reference was made to the
natural vegetation plots because soil conditions are signifi-
cantly different. The natural vegetation plot was retained
at its natural organic layer and received no lime additions
to control soil pH.
Groundwater contamination was observed initially at the
Lakewood Sand location. Contaminant concentrations were also
greatest at this site. The Lakewood 89.6 t/ha/y plot had an
average contaminant concentration 1.5 to 4.0 times greater
than the average contaminant levels observed beneath the 89.6
t/ha/y Woodmansie and Downer plots for such sludge-related
constituents as nitrate-nitrogen, specific conductivity,
chloride, sulfate, sodium, and calcium. Average contaminant
breakthrough concentrations beneath the Lakewood 44.8 t/ha/y
plot were also 1.5 to 4.0 times greater than the average
levels reported at the Downer and Woodmansie plots receiving
the same wastewater solids loadings.
Contaminant concentrations at the Downer 44.8 t/ha/y
plot were slightly greater than the contaminant level found
beneath the Woodmansie 44.8 t/ha/y plot.
The Downer and Lakewood 22.4 t/ha/y plots showed no sig-
nificant differences in average concentration for nearly all
constituents analyzed. Breakthrough concentrations beneath
the Woodmansie 22.4 t/ha/y plot were generally two to three
times greater than those found at the Downer and Lakewood
locations. It should be noted that the groundwater quality
results for the Woodmansie 22.4 t/ha/y plot were obtained
from observation Well 'B1 (center well). Comparison of
.groundwater quality data for the 'B1 and 'C' wells at each
22.4 t/ha/y plot tend to indicate contaminant levels were
similar at Downer and Lakewood sites, but significantly differ-
ent for the Woodmansie sand. For example, average nitrate-
nitrogen concentrations (Figure 30) for the 'B1 and 'C'
wells at the three 22.4 t/ha/y application plots were quite
similar at the Lakewood and Downer soils, however, average
N03-N levels beneath Woodmansie soil varied significantly:
11.9 mg/1 for the 'B1 well and 4.4 for the 'C' well. The
125
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Figure 30. Peak and average Nitrate-Nitrogen bres
through concentration for "B" and "C" Well
beneath 22.4 t/ha/y Plot-
126
_
-------
peak NC>3-N concentrations were also disproportionate: 38 mg/1
and 10.5 mg/1 for the VB' and 'C' wells, respectively. The
well driller log indicated that the soil characteristics of
Well 'CT at the Woodmansie 22.4 t/ha/y application was mostly
sand. However, soil characteristics in the area of Well 'A1
and 'C' indicate considerable silt and clay development.
Therefore, breakthrough concentration of contaminants would be
considered higher., at Well 'C'. Considering the soil charac-
teristics at the Well VB' emplacement, the groundwater quality
data should be considered not representative of the Woodmansie
soil location.
The application of wastewater solids on the Lakewood soils
appeared to produce the greatest breakthrough of contaminants
into the groundwater. The Woodmansie soil had the lowest
contaminant concentrations because of considerable silt and
clay development in the lower face and substratum of the soil.
Where soil characteristics were similar to that of a coarse
sand and substratum clay development was minimal, even the low
wastewater solids loading rate of 22.4 t/ha/y can cause high
contaminant breakthrough concentrations. Contaminant leaching
according to soil type and solids loading rates were as
follows:
Loading Rate
t/ha/y
22.4
44.8
89.6
Contaminant Breakthrough
According to Soil Series
Lakewood > Downer >Woodmans ie
Lakewood j>> Downer^- Woodmansie
Lakewood^' Downer ^ Woodmansie
It should be noted that the above conclusions do not reflect
the groundwater quality results reported for well TB' on the
22.4 Woodmansie application plot because the well was in-
stalled in a sand not characteristic of the Woodmansie soil
series. This particular well had contaminant breakthrough
concentrations almost equivalent to the levels observed
beneath the Woodmansie 89.6 t/ha/y plot.
GROUNDWATER CONTAMINATION BENEATH THE NATURAL VEGETATION PLOTS
At each application site one plot was retained in its
"natural" state, to assess the effects of surface spraying of
wastewater solids on a natural vegetation-soil-groundwater
system. A wastewater solids application rate of 44.8 t/ha/y
was utilized on these plots. Unlike the cleared plots where
the organic layer was removed and the soil pH was adjusted,,
the natural vegetation plots were not disturbed and no
additional lime was applied to control pH.
127
-------
The breakthrough of sludge-related constituents was in
general not observed during the first year (1973) of ground-
water sampling. However, analyses of samples obtained in
January and April 1974 did show that concentrations of many
groundwater constituents had increased above background levels
For example, nitrate-nitrogen levels increased from an average
background of less than 0.2 mg/1, to 3.0 and 6.0 mg/1 beneath
the Downer, Lakewood, and Woodmansie natural vegetation plots
respectively. After April 1974 contaminant concentrations
decreased until seasonal recharge occurred December 1974.
December contaminant breakthrough concentration of most
sludge-related constituents more than doubled the values
reported that previous April. Table 23 shows the adverse
effect on groundwater quality caused by this December slug
of contamination. For example, the chloride concentration
increased to 366 mg/1 beneath the Woodmansie natural vegeta-
tion plot.
In
128
-------
TABLE 23. CONTAMINANT CONCENTRATION BENEATH THE NATURAL
VEGETATION PLOTS
Contaminant
Plot
Colliers Mills
Downer
Webbs Mill
Lakewood Woodmansie
Specific Con-
duct ivity-
umhos/cm
Nitrate-
nitrogen-
mg/1
Chloride
mg/1
Sulfate-
mg/1
Total Hard-
ness -mg/1
107
3.2
22
24
11.8
April 5, 1974
137
3.0
265
6.0
17
10
15.5
24
48
37
Specific Con-
ductivity-
umhos/cm
Nitrate-
nitrogen-
mg/1
Chloride-
mg/1
Sulfate-
mg/1
Total Hard-
ness-mg/1
December 22, 1974
340 316
16.5
68
46
50
17.2
52
36
63
796
14.8
366
133
172
129
-------
In 1975 average contaminant concentrations beneath the
Downer and Woodmansie natural vegetation plots increased sharply
above those reported in 1974. At the Lakewood natural vegeta-
tion site, contaminant concentrations were generally lower with
only a periodic slug of contamination entering the groundwater.
Analysis of the 1976 groundwater quality data indicated
contaminant concentrations similar to the levels reported in
1975 for the first four months of the year. However, after
April contaminant levels began to decrease considerably, but
concentrations beneath these plots did not return to natural
background levels.
The general changes in groundwater quality as a result of
contamination from wastewater solids applications is summarized
by the response of N03-N over time shown in Figures 31, 32
and 33 for the Downer, Lakewood, and Woodmansie natural vege-
tation plots. Figure 31 for the Downer Plot and Figure 33 for
the Woodmansie plot identify the initial contaminant break-
through in early 1974, the large increase in contaminant con-
centrations in 1975 and early 1976, and the gradual decrease in
contaminant levels during the Spring and Summer of 1976. How-
ever, the magnitude of contaminant concentrations is quite
different. The difference in contaminant levels is even more
evident when compared to the contaminant response at the Lake-
wood site (Figure 32).. The initial breakthrough of contaminents
is similar to that of the Downer and Woodmansie on natural
vegetation site, but after the initial breakthrough only an
occasional slug of contamination enters the groundwater. The
marked differences in contaminant levels seem to be caused by
differences in soil pH. The Woodmansie soil had the lowest pH,
followed by the Downer soil and-Lakewood soil, respectively.
The range and average soil pH beneath the natural vegetation
plot for the three soil types are shown in Table 24.
TABLE 24. SOIL pH BENEATH NATURAL VEGETATION PLOTS
Soil Type
Woodmansie
Downer
Lakewood
pH
Range
4.0
4.0
4.0
- 4.6
- 4.7
- 6.8
Averages
4.3
4.7
5.0
130
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The depressed pH of the Downer and Woodmansie soils appears
to explain the greater leaching of sludge-related constituents
observed at these natural vegetation plots as compared to the
contaminant concentrations observed beneath the Lakewood natural
vegetation plot. According to soil pH contaminant concentration
should be greatest at the Woodmansie site, second at the Downer
site, and lowest at the Lakewood site. The average concentra-
tions of specific conductivity, nitrate-nitrogen, chlorides,
sulfates, soclium, calcium, ammonia nitrogen, and total organic
carbon tend to support this argument.
The applications of wastewater solids on natural vegetation
plots caused a significant deterioration of groundwater quality.
The naturally acid soil conditions which were not corrected by
the addition of lime resulted in concentration of many sludge-
related constituents approaching and even exceeding the values
reported for the more heavily loaded 89.6 t/ha/y application
plots. Contaminant concentration beneath the three natural
vegetation plots seem to vary according to the soil pH. Ground-
water contamination was the greatest beneath the Woodmansie plot,
where the average soil pH was as low as 4.3. These acid condi-
tions significantly increased the mobility of many sludge con-
stituents, particularly ammonia nitrogen, organic acids (TOC)
and even heavy metals. Compounding the acid soil conditions is
the lack of harvesting of a cover crop which would remove many
of the sludge constituents from the application site. There-
fore, the natural vegetation site becomes a permanent repository
for wastewater solids, thus increasing the potential for ground-
water contamination.
From these observations it appears the application of
wastewater solids at a rate of 44.8 t/ha/y is not suitable for
natural vegetation areas typical of the New Jersey Pine Barrens.
Cumulative Effect on Groundwater Quality from
Yearly Application of Wastewater Solids
The cumulative impact.of wastewater solids applications on
groundwater quality was studied over a four (4) year period.
Application of wastewater solids in Ocean County was initiated
in May 1973 and was applied for three (3) years until October
1975. There were no solids applied during the late fall and
winter months. Groundwater monitoring was also performed during
this period and was continued for an additional year through
October 1976, thus a complete year of groundwater quality data
was obtained after wastewater solids applications were discon-
tinued.
Contaminant breakthrough concentrations beneath the 22.4
t/ha/y application plots initially increase, but then stabilized
after two years of wastewater solids applications. At the other
134
-------
extreme, contaminant levels beneath the sandy soil Lakewood 44.8
t/ha/y and 89.6 t/ha/y plots steadily increased over the four-
year study. Contaminant concentrations also increased beneath
the Woodmansie 44.8 t/ha/y during all four years of the project,
however, the increase was very small and gradual as compared to
the breakthrough concentrations observed at the Lakewood plot
receiving the same wastewater solids loading. Beneath all other
plots, contaminant concentrations increased during the first
three years of the study, but decreased or remained stable
during the forth and final year of sampling. Although a decrease
in contaminant levels was observed at many plots, in no case did
the contaminant concentrations of such sludge-related consti-
tuents as chloride, sulfate, calcium and nitrate return to back-
ground levels. Table 25 summarizes these relative yearly
changes in contaminant breakthrough concentrations for the 12
wastewater solids application plots.
Effects of Rainfall on Contaminant Breakthrough
The downward displacement of sludge-related constituents
in the soil is dependent upon the frequency and intensity of
rainfall and time of the year. Late spring and summer months
are a period having high evapotranspiration rates and maximum
uptake of sludge constituents by cover crops. However,
periodic slugs ,of contamination were observed during the sum-
mer months as a result of very frequent and heavy rains,
particularly in 1975. The 1975 rainfall was considerably
above the normal for this area. The fall and winter months
can be characterized as seasons with low evapotranspiration
rates and minimal plant uptake of sludge constituents, thus
transport of water into the groundwater from resulting rain-
falls was increased and in turn, groundwater contamination
sharply increased.
As the intensity of a rainfall increased contaminant
breakthrough concentrations were found to increase. It was
also observed that the longer the dry period previous to a
rainfall, the greater the contaminant breakthrough levels
beneath the application plots following the rainstorm. The
critical periods of contaminant breakthrough appeared to
occur during rainfall events which recharged the aquifer.
A single rainfall event cannot be correlated to the
breakthrough of sludge-related constitutents entering the
groundwater. Other factors must be considered concurrently
when-analyzing contaminant breakthrough. The factors are
the intensity of rainfall, frequency of rainfall, dry period
previous to a rainfall event, evapotranspiration rate, growing
season, frozen ground and rainfall events leading to the direct
recharge of the aquifer. Perhaps the best parameter associated
with the occurrence of contaminant breakthrough is recharge
135
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events. A rainfall or series of rainfalls resulting in ground-
water recharge, can considerably increase contaminant concentra-
tion levels beneath the application plot; however, successive
recharge events can also cause a dilution in contaminant con-
centration beneath the plot, near the water table. Therefore,
yearly analysis of well hydrograph should be considered in
conjunction with groundwater quality monitoring to identify
periods of contaminant b.reakthroughs. Generally, the late
fall and winter months, when the aquifer is recharging, is when
the application plots are most susceptible to contaminant break-
throughs. This behavior is illustrated in Figures 34 and 35
in which monthly response of specific conductance and nitrate-
nitrogen are compared to fluctuations in groundwater table and
rainfall events.
Seasonal Variations in Contaminant Concentrations
Breakthrough concentrations beneath an application plot
were considerably greater during the fall and winter months.
Sludge-related constituents are generally more mobile as a
result of increased moisture levels in the soil. The rates of
reversion and evapotranspiration also are substantially lower.
Climate and soil conditions are optimum for groundwater recharge.
Since there is no active growth during these months, sludge-
related constituents normally utilized by the cover crops are
also transported through the soil solution into the ground-
water. Therefore, rainfall during the fall and winter months
which recharged the aquifer caused considerable groundwater
contamination.
Figure 36 clearly illustrates these seasonal differences
in contaminant breakthrough beneath an application plot.
Comparison of Contaminant Concentrations to Drinking
Water Standards
Contaminant breakthrough concentrations were compared to
National Intern Primary Drinking Water Regulations proposed by
the U.S. Environmental Protection Agency and the Potable Water
Standard established by,the State Department of Environmental
Protection of the State of New Jersey.
These standards were compared to the average increase of
contaminant breakthrough concentrations over background levels
at each application plot. A total of 23 groundwater consti-
tuents were tabulated according to plot loading rates and
soil type. Table 26 presents the average increase of con-
taminant breakthrough concentrations for these 23 constituents.
It should be noted that there are groundwater quality data for
two observation wells for the Webbs Mill, Woodmansie 22.4 t/ha/y
137
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plot (Table 26). The 'B' well on this plot was installed in a
pocket of sand not characteristic of the Woodmansie soil series
(no clay or silt lenses at lower depth), while Well 'C' was
drilled in a soil typical of the Woodmansie series. Therefore,
the data corresponding to Well 'C' for the 22.4 t/ha/y Wood-
mansie plot is more representative than the Woodmansie series,
while data reported for the 'B' well would be characteristic
of a very sandy soil. Two additional distinctions pertaining
to groundwater quality are also identified in Table 26: _(1)
when the contaminant concentration is at or above the drinking
water standard and (2) when the contaminant concentration is
within 50% of the maximum limit.
Heavy metals did not appear to have a significant impact
on groundwater quality. The average concentrations of all the
heavy metals were generally equivalent to or slightly above
the natural background levels. When a marginal increase in
metal concentration was observed, particularly for zinc and
copper (refer to the Lakewood 89.6 t/ha/y and Woodmansie
natural vegetation plots), it was well below the maximum
contaminant limits for potable water.
The comparison of contaminant breakthrough concentrations
beneath individual plots to potable drinking water standards
was performed utilizing the average contaminant concentration.
The peak concentrations were not considered in this comparison.
It appeared the average contaminant concentration was more
representative of the long-term response of the groundwater
system to contaminant breakthrough, while the peak concentra-
tion was only the maximum level observed at only one single
point in time. Therefore, the average contaminant concentra-
tion was selected for the analysis.
No specific organic analyses were performed on the ground-
water samples. Only the coarse measurement of total organic
carbon was obtained for each sample. Total organic carbon was
found to have increased above background level beneath many
of the plots. The breakthrough of organic carbon as measured
by TOG tends .to indicate that trace organics may have entered
the groundwater. This is particularly true for those plots
receiveing the higher wastewater solids loadings, Lakewood 89.6
t/ha/y plot and where soil conditions are extremely acid as
was the case with all the natural vegetation plots.
Nitrate-nitrogen was the limiting groundwater chemical
constituent with respect to drinking water standards. Addi-
tionally, average breakthrough concentrations of total dis-
solved solids, chlorides, sulfates, and total hardness (calcium
and magnesium) were approaching, and in many cases exceeded,
145
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the recommended limit beneath the following plots: plots
receiving 89.6 t/ha/y of wastewater solids, natural veg-
etation plots (Downer and Woodmansie) and where soil char-
acteristics were similar to that of a coarse sand. For the
Downer and Woodmansie soils, it would appear a surface waste-
water solids loading rate in excess of 22.4 t/ha/y and
possibly as much as 44.8 t/ha/y could be applied without
violating the potable water standards downgradient from the
application site. In the case of the more sandy Lakewood
soil, the maximum allowable loading rate appears to be 22.4
t/ha/y. However, where the soil is characteristic of a
coarse sand, containing little or no silt or clay lenses,
even the 22.4 t/ha/y application rate could violate potable
drinking water standards. It should be noted that the appli-
cation rates suggested are based on contaminant levels directly
beneath the application plot. They do not reflect the possible
dilution downgradient of the application plot from the natural
diffusion and dispersion of the contaminant in the groundwater.
Nitrate-Nitrogen Contamination !
The land application of wastewater solids has resulted in
groundwater contamination above baseline levels beneath almost
all plots. However, the extent of contamination and possible
groundwater pollution was found to be significantly dependent
on wastewater solids, loading rates, soil character, and soil
pH. The groundwater chemical constituent which caused the
greatest concern was nitrate-nitrogen (NC^-N). The nitrate-
nitrogen breakthrough concentrations beneath most application
plots receiving the larger wastewater solids loadings were in
violation of the present Federal drinking water standard of
10.0 mg/1 N03-N. Nitrate-nitrogen levels ranged as high as
102 mg/1 at the Webbs Mill-Lakewood'89.6 t/ha/y plot.
The 'D1 and 'E' wells were installed downgradient of the
application site according to the original potentimetric maps
determined at the beginning of the study in 1973. However
it was found that the direction of the flow shifts under
changing conditions of flow gradients, recharge and discharge.
Therefore, the positions of several downgradient profile
samplers were relocated to identify the zones of contamina-
tion^within the groundwater system. Thus, the concentration
of nitrate-nitrogen reported for these wells at the water
table level were suspect due to changing flow direction. The
result was a value considerably lower than the representative
concentration which lies directly along the line of flow.
Skim-samples withdrawn from downgradient wells were also some-
what diluted because those wells were not subject to vertical
nitrate breakthrough, but are subject to groundwater recharge;
hence, dilution. Additionally, the peak and average N03-N con-
centrations reported do not identify significant dynamic trends
146
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within the groundwater system; i_.e_. , increase or decrease in
N03-N levels as contaminant travels through the system.
Average nitrate-nitrogen concentrations beneath and down-
gradient of the Colliers Mills-Downer and Webbs Mill-Lakewood
22.4 t/ha/y application plots were less than 4 mg/1. However,
directly beneath the Webbs Mill - Woodmansie 22.4 t/ha/y appli-
cation plot, NOs-N concentrations were considerably greater.
The peak NOs-N concentration was 38 mg/1; and the average
N03-N concentration was in excess of 10.0 mg/1. Downgradient
from the Woodmansie 22.4 t/ha/y plot levels of nitrate-nitrogen
contamination were minimal compared to concentrations beneath
the application plot. This skewed effect among plots was the
result of an atypical pocket of sand located in the center of
the Webbs Mill - Woodmansie 22.4 t/ha/y plot.
1 Nitrate-nitrogen concentrations beneath the cropped plots
receiving a wastewater solids loading of 44.8 t/ha/y were
considerably greater at the Webbs Mill-Lakewood plot than at
the other two (2) locations. The peak and average nitrate-
nitrogen concentrations at the water table level were 79 and
31 mg/1, respectively. Nitrate breakthrough levels at the
Colliers Mill-Downer and Webbs Mill-Woodmansie 44.8 t/ha/y
plots' were generally less than 10 mg/1 NOs-N. Although
breakthrough concentrations may have been less than 10.0
mg/1 NC^-N beneath these plots, profile samples tended to indi-
cate that significant nitrate-nitrogen contamination above
the 10.0 mg/1 'level had occurred downgradient of these appli-
cation plots.
Considerable NO-z-N contamination occurred at the natural
vegetation plots. N03~N breakthrough ranged as high as 89
mg/1 beneath the Webbs Mill-Woodmansie plot. Downgradient
contamination was also substantial at the Colliers Mill-
Downer and Webbs Mill-Lakewood natural vegetation plots. For
example, N03-N levels were as high as 32 and 30 mg/1 at dis-
tances of 30.5m and 61m downgradient of the Colliers Mills-
Downer plot, respectively.
Nitrate-nitrogen contamination was the greatest at the
application plots receiving a wastewater solids loading of
89.6 t/ha/y, particularly at the Webbs Mill-Lakewood site.
Nitrate-nitrogen levels beneath the Webbs Mill-Lakewood 89.6
t/ha/y plot ranged as high as 102 mg/1. Downgradient N03-N
from the values reported directly beneath the plot. Peak
N03~N concentrations 30.5m and 61m downgradient from the
application plot were 96 and 74 mg/1, respectively.
147
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-80-090
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
WASTEWATER SOLIDS UTILIZATION ON LAND
DEMONSTRATION PROJECT
5. REPORT DATE .
August 1980 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
Ocean County Sewerage Authority
Cook College, Rutgers University
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Ocean County Sewerage Authority
Bayville, New Jersey 08721
10. PROGRAM ELEMENT NO.
C36B1C
11. CONTRACT/GRANT NO.
S801871
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory- Cin., OH
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final; June 1972-Oct. 1976
14. SPONSORING AGENCY CQDE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer, Kenneth Dotson (513-684-7661)
16. ABSTRACT
This is a summary report of a four-year field study of the techniques and
environmental effects of applying liquid digested municipal sludge at various
rates to sandy coastal plains soils in a humid temperate climate. Some of the
most important observations and measurements were effects on groundwater movement
and quality, crop quality and yields, air quality, soil properties, and
wildlife. Recommendations for safe beneficial sludge use under conditions
of the study are presented. The report should be valuable to planners and
designers of sludge disposal facilities and to managers of land application
sites in humid temperate areas.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Sludge disposal, Land reclamation,
Water quality, Sludge, Coastal Berms,
Trace elements, Groundwater
Metals, Digested sludge,
Soil treatment,
Toxic elements,
Soil conditioner,
Crop quality
13B
08M
3. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (Tills Report/
UNCLASSIFIED
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
148
U.S. GOVERNMENT PRINTING OFFICE: 1980—657-165/01.35
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