&ER&
United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-019 May 1982
Project Summary
Spreading Lagooned Sewage
Sludge on Farmland:
A Case History
C. Michael Robson and Lee E. Sommers
This report describes a case history
on the use of anaerobically digested
(stabilized) sewage sludge on agricul-
tural land. Although this project
involved a single application of sludge
to soils, it revealed much about equip-
ment, procedures, and regulatory
agency requirements.
The case history describes the dis-
posal of approximately 420,000 m3
(111 million gal) of stabilized sludge
and other materials that had been
stored in holding lagoons at the Bel-
mont, Indiana, Wastewater Treat-
ment Plant, which is owned and
operated by the Department of Public
Works of the Consolidated City of
Indianapolis, Indiana. The stabilized
sludge and other materials were
removed to enable the construction of
new wastewater treatment facilities
on portions of the Belmont site pre-
viously occupied by the sludge
lagoons. The major portion of the
sludge (265.000 m3) was disposed of
by application to privately owned cro-
pland in adjacent Boone County,
Indiana.
Cadmium (Cd) and polychlorinated
biphenyl (PCB) contents of the sludge
were the major constraints in deter-
mining the sludge application rates to
the cropland. Frequent analyses of the
sludge solids were needed to identify
the appropriate rates. Landowners
consigned about 5,000 ha (13,000
acres) for a single sludge application,
after which corn and soybeans were
grown. An effective public relations
program minimized public resistance
and secured the cooperation of area
residents.
Analyses revealed no measurable
increases in the Cd and PCB contents
of the grain after the single sludge
application. Techniques were devel-
oped for removing, transporting, and
applying lagooned sludges and for
administering and monitoring such a
program.
This Project Summary was devel-
oped by EPA's Municipal 'Environ-
mental Research Laboratory,
Cincinnati, OH. to announce key find-
ings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Disposal of sludge produced during
municipal wastewater treatment is a
severe problem. To select a disposal
method, an agency must consider
numerous factors, including costs, pro-
tection of the public health, pollution of
air, water, and land, public acceptance,
and resource conservation and recov-
ery. Land application of stabilized sew-
age sludge has become a viable sludge
disposal option. Benefits of this method
result from the use of sludge as a low-
analysis fertilizer and soil conditioner.
When the city of Indianapolis, Indi-
ana, was required to construct
advanced wastewater treatment facili-
ties at the existing Belmont Wastewater
Treatment Plant, they determined that
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the most cost effective site for these
new treatment facilities was the 10
sludge lagoons containing 420,000 m3
(111 million gal) of digested sewage
sludge for up to 50 years. Of the
420,000 m3 of sludge originally con-
templated for disposal by land spread-
ing, 265,000 m3 was actually spread on
land and the remainder disposed of in a
landfill. The site preparation contract
was awarded to a contractor who chose
to dispose of the lagooned sludge by
applying it to privately owned agricultu-
ral cropland in adjacent Boone County,
Indiana.
Procedures
The project consisted of the following
major tasks: (1) obtaining approval from
regulatory agencies; (2) obtaining coop-
eration of landowners and farmers; (3)
removing, transporting, and applying
the lagooned sludge to soil; and (4)
monitoring the impact on crops.
Undefined state and Federal regula-
tions hampered initiation of the project.
To determine appropriate rates for
sludge application on cropland, exten-
sive analyses were conducted of the
sludge stored in the lagoons. As
expected, the sludge solids content was
extremely variable, ranging from U1%
near the surface to "30% at a 5-m depth.
The Cd and PCB contents of the sludge
were major constraints in determining
sludge application rates to cropland.
The Cd concentrations ranged from 122
to 241 mg/kg (with an average of 179).
Sludge application rates were initially
based on 1.1 kg Cd/ha and later
increased to 2.1 kg/ha. The maximum
amounts of lead (Pb), zinc (Zn), nickel
(Ni), and copper (Cu) applied-were less
than 26,48, 22, and 2.6 kg/ha, respec-
tively. Corn and soybeans were the
crops grown after a single soil applica-
tion of the sludge.
The subcontractor responsible for the
sludge application developed an effec-
tive public relations program involving
demonstration plots, radio and news-
paper advertising, and written mate-
rials. Landowners consigned about
5,000 ha (13,000 acres) for sludge
application. The subcontractor col-
lected the soil samples, provided soil
and sludge analysis data, and applied
limestone when the soil pH was below
6.5.
The sewage sludge was resuspended
in each lagoon, pumped into semi-
trailer tankers, trucked to Boone
County, and either applied immediately
or placed in temporary storage lagoons.
A variety of equipment was used to sur-
face apply or inject the sludge into soil.
Adverse weather conditions reduced
the time available for sludge application
and thereby delayed project completion
by several years.
Discussion
Sludge Disposal Procedures
A high rate of sludge handling was
achieved by using procedures and
equipment developed in similar bulk
material handling industries. A cable-
controlled, pontoon-mounted device
was used to homogenize and move the
sludge in the lagoons to a pump station
for transfer to a truck loading station.
Four large semi-trailer tankers could be
loaded in 5 min at the bulk-fuel-oil type
loading facility.
Each tanker truck transported 29.5
m3 of sludge over 80 km (50 miles) to an
adjacent county where it was again
transferred to a field-spreading vehicle
or to an interim sludge-holding lagoon.
A variety of spreading equipment was
used over the 4-year sludge speading
period. The contractor initially used
low-speed, agricultural-type equip-
ment. This equipment was unable to
maintain high rates of sludge applica-
tion on a round-the-clock basis. The
heavier, faster, construction-grade
spreading units used in the last 2 years
of the project demonstrated the availa-
bility of equipment for large-scale land
application of sludge projects. Summar-
ized specifications for this type of equip-
ment are included in the report.
Public Relations
Even though a technically sound
sludge application program might be
designed, public opposition could pre-
vent the program from being initiated.
The contractor therefore realized that
an effective public relations program
was essential to insure acceptance of
sludge utilization in the county where
sludge was to be spread. Two sectors of
the public were addressed by the public
relations program: The farmers who
were to receive the sludge, and their
neighbors. The farmers needed to be
convinced of the economic benefit of
using sludge, which in their experience
was an unknown soil amendment when
compared with conventional fertilizers.
The neighbors of the farmers were sen-
sitive about the dumping of urban
wastes in rural communities, and their
concerns included odors, pathogens,
and groundwater pollution.
The contractor addressed the public
relations problem with a broad
approach that included: (a) establishing
good media relations, (b) holding group
meetings, (c) carrying out test plot dem-
onstrations, (d) having a motion picture
of the project prepared for loca I viewing,
and (e) gaining the active Support of
agronomy experts.
Retention of a Consulting
Agronomist
The city identified a need for a person
with special expertise in the field of
sludge disposal on agricultural land. In
addition to providing technical assist-
ance, this consultant provided addi-
tional project credibility with both the
general public and the regulatory agen-
cies. At the request of the city, the con-
sulting agronomist prepared an
evaluation of the agronomic implica-
tions of the land application of sludge
for this project. He concluded that the
project was well designed and incorpo-
rated the latest concepts for land appli-
cation of sludge. The consulting
agronomist supported the Indiana State
Board of Health (ISBH) requirements for
continuous monitoring of the sludge
removal and spreading operations. He
continued to be associated with the pro-
ject in a consulting role and was
involved in designing a program for
sampling and analyzing the corn and
soybean crops raised on sludge-treated
fields.
Crop Monitoring
The state regulatory agency required
that samples of corn and soybean grain
be collected and analyzed the first year
after sludge applications. Random sam-
ples of grain were collected by hand
harvesting in September of each year.
Samples were collected from both the
sludge-treated fields and adjacent
fields not treated with sludge. Because
the same varieties of corn and soybeans
were not necessarily grown in adjacent
fields, the comparisons of Cd and PCB
concentrations in crops grown on
sludge-treated and non-sludge-treated
areas (Table 1) may reflect the influence
of both crop variety and sludge applica-
tion. All crop samples were obtained
during the first cropping season after
sludge application. In 1978, some corn
grain samples showed slightly
increased concentrations of Cd. No Cd
or PCB's were present at detectable lev-
els in any subsequent samples of corn
and soybean grain.
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Table 1.
Concentrations of Cadmium and PCB's in Corn and Soybean Grain
Grown on Sludge-Treated and Untreated Soils in Boone County,
Indiana (ug/kg)
PCB in Grain
Cd in Grain
Year
1978
1979
1980
Crop Sludge-Treated
Corn (9f <1
Soybeans (6) <1
Corn (9) <1
Corn (12) <1
Untreated
1
Sludge-Treated
100
60
<50
<50
Untreated
<20
<50
<50
<50
a The numbers in parentheses indicate the total number of samples analyzed.
Conclusions
This project demonstrates that a met-
ropolitan treatment plant can remove
and apply to croplands a large volume of
liquid stabilized sewage sludge that has
been stored in lagoons. The project
involved transportation of the sludge by
semi-trailer tankers and either surface
or subsurface application to cropland
with conventional equipment. The
sludge was applied on privately owned
land in an adjacent rural county through
a cooperative agreement between the
farmers and contractor.
The planning and conduct of a land
application project requires expertise in
many technical and sociological disci-
plines. Critical areas identified during
this project include materials handling
and transport, public relations, sludge
application equipment, soil and crop
production, soil and groundwater moni-
toring, sludge application and crop pro-
duction scheduling, experience in
relating to farmers and their problems,
obtaining regulatory approvals, and
establishing the mechanism for flow of
project data and information.
Adverse weather conditions caused
delays in applying sludge to farmland,
and the growth of row crops (corn and
soybeans) minimized the number of
days that sludge could be applied to
soils. Coordination of crop production
and sludge utilization programs is diffi-
cult because of uncertainties caused by
adverse weather conditions.
A public relations program must be
started very early in a project to obtain
the support of the agricultural commun-
ity. Both the benefits and problems
must be presented to all interested par-
ties. The project developed numerous
procedures for monitoring sludge appli-
cation rates and for maintaining a wide
variety of records. The equipment
initially chosen for applying sludge did
not perform as anticipated. Alternative
equipment was selected later that could
withstand continuous use. All equip-
ment should be evaluated onsite before
purchase.
A single application of sewage sludge
at a rate ranging from 1.12 to 2.1 kg
Cd/ha caused no measurable increases
in the Cd content of corn and soybean
grain. Plant uptake of PCB's was also
not detectable.
If at all possible, off site storage of
sludge in either temporary or perma-
nent lagoons should be avoided. A far
preferable procedure is to locate stor-
age lagoons near the treatment plant
and then transport the sludge just
before it is to be appl ied to cropland. The
two temporary storage lagoons near the
sludge spreading site resulted in the
only negative public response to the
land application project.
This project demonstrates that a large
metropolitan sanitary district can trans-
port and apply sludge to cropland in a
neighboring rural area without wides-
pread public resistance. To accomplish
this goal, it is essential to involve local
agricultural leaders, develop an effec-
tive and honest public relations pro-
gram, use aesthetically acceptable
methods for sludge application, and
develop sludge application procedures
compatible with prevailing farming
practices.
The full report was submitted in ful-
fillment of Contract No. C2575NASX by
C. Michael Robson under the sponsor-
ship of the U. S. Environmental Protec-
tion Agency.
C. Michael Robson and Lee E. Sommers are with Purdue University, West
Lafayette, IN 47907.
Gerald Stern is the EPA Project Officer (see below).
The complete report, entitled "Spreading Lagooned Sewage Sludge on Farm-
land: A Case History," (Order No. PB 82-181 082; Cost: $12.00. subject to
change! will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati. OH 45268
•ft US GOVERNMENT PRINTING OFFICE. 1982 — 559-017/0728
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