United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-167 Jan. 1985
Project Summary
Technical-Economic Study of
Sewage Sludge Disposal on
Dedicated Land
Lilia A. Abron-Robinson and Leon W. Weinberger
This study documents the technical,
cost, and environmental factors involved
in sludge .disposal on dedicated land
(OLD). Three general types of OLD
operations were identified based on
cadmium and nutrient loadings to the
land.
Six sludge disposal sites (two of each
general type) were analyzed. Site visits
and existing data were used to determine
the relative environmental impacts and
costs for the three types of municipal
sludge application to DID sites.
Study results indicate that well
managed and properly used DLO sites
are environmentally acceptable even at
high sludge application rates. Cost
advantages for any of the three types of
sites are difficult to determine, however,
because costs are dictated by local
conditions and institutional, social,
political, and aesthetic factors.
This Project Summary was developed
by EPA's Water Engineering Research
Laboratory, Cincinnati. OH. to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Many municipal sewage treatment
agencies apply some of their wastewater
sludges to land to fertilize growing crops.
Generally the amount of sludge applied
depends on the nitrogen requirements of
the crop(s), the cadmium application
rates, and other limitations as specified in
the "Environmental Protection Agency
Regulations on Criteria for Classification
of Solid Waste Disposal Facilities and
Practice," Environmental Protection
Agency 40 CFR Part 257, "Criteria for
Classification of Solid Waste Disposal
Facilities and Practices; Final, Interim
Final, and Proposed Regulations (as
corrected in the Federal Register of
September 21,1979)," and State regula-
tions or requirements. The sludge applica-
tion rate must be controlled to protect
groundwater supplies from possible
nitrate contamination and to prevent
excessive uptake of cadmium in growing
plants. Although nitrogen and cadmium
are the elements of the most frequent
concern and are the principal criteria
used inthis report, other heavy metals, in-
organic and organic toxic substances, nu-
trients, etc., could affect the land applic-
ability of wastewater sludges.
Many communities have adopted a
program of sludge application to land that
is used primarily for sludge disposal; the
growing of crops is incidental or nonexis-
tent. In these cases, relatively large
amounts of sludge may be applied. The
~ Federal criteria governing application
rates for nitrogen, cadmium, and other
constituents applicable to the production
of food-chain crops could be exceeded.
Usually the land that is dedicated to
sludge disposal is owned by the municipal-
ity, has limited public access, and is not
intended for future sale. Groundwater at
dedicated sites must be protected by
natural geological conditions, or the site
must be underdrained and the drainage
water must be treated before release. If
crops are grown, they must be either of
the non-food-chain type or meet the U.S.
Environmental Protection Agency (EPA)
criteria for animal feed.
Three types of DLD operations were
identified:
Type I: Sludge is applied according
to the nutrient needs of the
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crop. Cadmium application
limits specified by the EPA
are not exceeded.
Type II: Sludge is applied at rates
that supply more than the
crop's nutrient requirements,
and EPA annual cadmium
limits are equaled or exceeded.
Type III: Sludge is applied at rates
that greatly exceed crop
nutrient requirements, and
the EPA annual cadmium
limits are exceeded.
Based on the availability of cost and en-
vironmental data, six sites (two repre-
senting each type of DID operation) were
selected for analysis. Sludge application
and site data are given in Table 1. Sites
owned by municipal sewage agencies
that matched the Type I description exact-
ly and had cost and environmental data
available could not be located. Most mu-
nicipalities employing OLD apply sludge
at the maximum rates possible within
technical, land, and environmental limits.
Cost Analysis
The following elements and factors
should be considered in a' cost analysis
for sludge application on land:
Land
Site Preparation
Drainage
Drainage Treatment
Pumping Equipment
Roads
Environmental Monitoring
Table 1. Summary of Sludge Application and Site Data for Dedicated Land Operations
Type I Type II
Energy
Sludge Transportation Costs
Overhead
Interest Rates
Taxes
Type of Sludge Treatment
Value of Sludge as a Soil Conditioner/
Fertilizer
Sludge Application Rates
Crop Revenues
Labor
Table 2 summarizes costs for each
sludge application site studied and
itemizes them by certain cost categories.
To compare the different types of DLD
operations, the itemized costs have been
converted to cost per metric ton (t) of
sludge applied, based on the amount of
sludge applied at each site. For example,
Type III
Item
Application rate, dry solids:
t/ha
N, kg/ha
Cd. kg/ ha
P, kg/ ha
Application frequency, years
Sludge characteristics:
Solids - %
N-%ofDS
P-%ofDS
Cd - mg/kg
Haul distance (km)
Amount of land
Springfield,
Ohio
5
150
0.2
—
3
6.9
3
1.8
39
20f
47(
Toledo,
Ohio
11.2
230
0.22
330
6
22
2
2.9
20
1211
900*
Springfield,
Illinois
76
2,700
1.2
128
1
1-2
*
*
*
Onsite
15
Hanover ParK.
Illinois
34-45
1.480
1.74
—
1
2.44
5-7
1.5-2
10-120
Onsite
81
Fulton
County,
Illinois
44-83
3.9OO
86
2,539
1
6
4
3
280
321*
1,881
Sacramento,
California
224
13.450
4.5
4.500
1
4.1
5.9
1.9
19
Onsite
8
'Sludge applied in liquid form.
tRound trip.
*One way.
f£ach year for 3 years.
ttfach year for 6 years.
Table 2. Summary of Costs for Each Sludge Application Site (1980 Dollars}
Type!
Item
Transportation and
application
Monitoring
Land
Construction
Taxes
Sludge dewatering
Total Cost
Revenue from crops
Net Cost
includes only the application
^Amortized, 20 year life, 10%
^Farmer-derived benefit from
Springfield,
Ohio
($/t)
$93.00
93.OO
$93.00*
cost.
use of sludge.
Toledo,
Ohio
f$/t)
$68.00
7.00
98.00
173.00
$173.00*
Type II
Springfield,
Illinois
<$/t)
$45.OO*
6.00
51.00
$51 00
Hanover Park,
Illinois
l$/t)
$35.00*
4.00
69.00
119.0O\
226.00
15.00
$21 1.00
Type III
Fulton
County
Illinois
($/t>
$275.00
7.00
6.OO
5.00
293.00
3.00
$290.00
Sacramento,
California
($/t)
$41.00
6.00
0
47.00
$47.00
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land costs were originally given as $/ha,
which was converted to $/t based on
the amount of land (hectares) used per
ton of sludge applied. Although consider-
able cost data are available for each of the
sites, any direct comparison must take
into account major differences in opera-
tional mode, major unit price differences,
special local requirements, and the lack
of consistency in distributing the cost
items. These differences occur even
within the three types of sludge application
sites.
Type I Sites
The sludges for the Type I operations
(Springfield and Toledo, Ohio) are applied
to privately owned lands. The city of
Springfield personnel haul and apply the
sludge, whereas those functions are
performed by a contractor for Toledo, who
also receives some payments from the
farmers on whose land the sludge is
applied. The sludge application rate for
Springfield is 5 t/ha applied once in 3
years; for Toledo it is 11.2 t/ha applied
once in 6 years. Toledo dewaters sludge
to 22 percent solids and transports the
sludge to farms approximately 60 km
from the plant. Springfield dewaters
sludge to approximately 7 percent solids,
and the disposal sites are 10 km from the
plant. At both sites, farmers receive
nutrients at costs lower than commercial
fertilizers.
Type II Sites
As with Type I operations, the costs for
Type II sludge disposal operations in
Springfield and Hanover Park, Illinois, are
also different, partly because of the
difference in sludge disposal practices.
The Springfield, Illinois, site required
relatively little site grading and preparation
for spray application of sludge, whereas
the Hanover Park site had precision-
sloped fields for gated pipe sludge
application. The Springfield site can use
spray application of sludge because of its
isolated location, but the Hanover Park
site requires gated irrigation pipe for
sludge application to reduce sludge
visibility and minimize citizen complaints.
The Hanover Park site operation is close
to a comparatively affluent area and
therefore incurs higher labor and land
costs than the Springfield operation. The
sludge application rate used at Springfield
is nearly double the Hanover Park rate.
The Springfield operation has no monitor-
ing costs available, but monitoring costs
were estimated to be less than $6.00/t
based on the cost of monitoring for the
other sites studied. Some Hanover Park
costs are covered by sale of crops.
Type III Sites
The two Type III sludge application sites
also showed a wide range of costs. Wide
differences occurred in operations at
Fulton County, Illinois, and Sacramento
County, California. The Sacramento
operation does not incur a transporation
cost, whereas the Fulton County operation
is 321 km from the point of sludge
generation in Chicago. Capital and land
costs are quite similar because both
operations are located in rural .communi-
ties and both use a soil incorporation
method. Although no costs are available
for monitoring at Sacramento, it was
assumed that these costs would be
similar to those of the other sludge
application operations where monitoring
costs are available and that they would
probably be less than $6.00/t. But large
differences occur in the cost for sludge
application to land. These differences are
due to the relatively inexpensive seasonal
labor used at the Sacramento operation
and the more expensive labor that Fulton
County uses from nearby Peoria, Illinois.
Some of the Fulton County operation
costs are recovered by the sale of crops.
The latter operation also has real estate
and other taxes levied against it because
it is located outside the political boundaries
of the operating agency.
Summary of Costs
The relative cost effectiveness of the
three types of OLD operations was
impossible to determine from cost data
compiled for the six sludge disposal sites
studied. The cost data compiled were
influenced mainly by local conditions
and, to a smaller extent, by social and
aesthetic factors. The most important
cost factors affecting the economic
analysis are site preparation, land, sludge
transportation, and labor costs.
Social and Environmental Impacts
The social and environmental impacts
include the nonmonetary costs, benefits,
advantages, and disadvantages of sludge
disposal on land. Public acceptance was
cited as crucial to a successful operation
and assures good public relations. This
factor was found to be essential for all
types of sludge disposal operations.
Type I Sites
With this type of sludge disposal, the
municipality is not required to purchase
land. But new sites must be continuously
sought for sludge disposal. The farmers
who use sludge in place of inorganic
fertilizer reduce fertilizer costs and
increase crop yields. Though there were
some complaints about odor and increased
truck traffic at the Toledo site, these were
reduced by the private contractor, who
initiated street sweeping and vehicle
rinses to reduce odor complaints.
No extensive environmental monitoring
is conducted at either of the sites because
the sludge application rates satisfy the
restrictions. But at the Toledo site in the
spring, surface water, tile water, and well
water samples are analyzed before the
sludge application and afterward. No con-
tamination problems were detected.
Type II Sites
The Springfield site has no public
opposition or complaints probably because
of the remoteness of the site and the
sludge application process generates
little odor. At Hanover Park, where local
residents live close to the site, the
experimental farm was accepted. Both
sites provide a permanent repository for
sludge.
A more detailed environmental monitor-
ing program is required for Type II sites.
Soil samples taken at the Springfield site
revealed no significant accumulation of
heavy metals. Cadmium levels increased
in plant tissues, but by less than 1.0/ug/g.
All surface water runoff is returned to the
treatment plant. The monitoring results
at the experimental farm at Hanover Park
indicate no adverse environmental
impacts. Virtually no change has occurred
in groundwater quality since 1968. All
underdrainage is returned to the treatment
plant. Crop yields were greater with
sludge application than with inorganic
fertilizer.
Type III Sites
The main advantage of Type III sludge
disposal operations is that land require-
ments are minimized and application
rates are maximized. The flexibility of
sludge application rates is also increased.
Both sites provide a permanent repository
for sludge. Fulton County originally used
traveling sprinklers for sludge application,
but an incorporation device is now used
because it can apply a greater amount of
sludge with reduced visibility to the
public. Cooperation with local officials
(who wish to restore the strip-mined land)
proved invaluable to public relations at
Fulton County.
Adverse impacts at the Sacramento
site have been identified in the planning
process. Wind machines and barriers will
be used to mitigate odor problems. Buffer
lands producing forage crops and leased
for seasonal grazing will also limit
impacts. Sludge injection wifl be used to
reduce odor problems. There is no
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intention of growing crops at the Sacra-
mento site.
Although monitoring data are not
available on the Sacramento site, the
experimental farm data indicate that soil
metal levels will increase with sludge
application. Extensive environmental
monitoring is required at the Fulton
County site. Runoff water is stored until it
meets Illinois standards for release to the
adjacent stream. No significant change
has occurred in surface water quality, but
metal content of the soil has increased.
Ammonia levels are well within the
prescribed limits, and the N02+NO3-N
concentration has not changed in ground-
water wells. Essentially, the sludge
disposal at Fulton County has restored
the strip-mined land without adverse
impacts.
Regulatory Aspects
Sludge disposal on land is subject to
regulations at the Federal, State, and
local levels. The EPA has regulations on
criteria for classification of solid waste
disposal facilities and practices. State
and local authorities may regulate
disposal operations through laws, statutes,
ordinances, guidelines, land-use regula-
tions, permit conditions, criteria standards,
rules, and regulations. In general, each
jurisdiction has a different approach to
controlling or regulating a site, and
conditions tend to be site-specific.
Type I Sites
Both sites are located in Ohio and
subsequently are subject to the Ohio
Sludge to Land Guidelines. The latter
give sludge application rates to land
based on soil cationic exchange capacity
(CECy. In addition, the guidelines require:
(1) that sludge having a cadmium level
greater than 25 /jg/g (dry weight) not be
applied to farmland if that level is greater
than 1.5 percent of'the zinc content, (2)
that yearly application of cadmium be
limited to 2.2 kg/ha, and (3) that the soil
pH always be 6.5 or higher. Both State
and Federal guidelines are met by both
Type I sites.
Type II Sites
The EPA limits the use of crops grown
at these sites to animal feed — not food
for human consumption. The Illinois EPA
has no documented guidelines, but it
reviews each case on a site-by-site basis.
The Hanover Park permit required that all
underdrainage be returned to the treat-
ment plant influent, and it restricted
land application methods to gated irriga-
tion pipe for adequate control of odor
emissions.
4
Type III Sites
The Fulton Country site has permit
restrictions that specify 18 special
conditions relating to how the. sludge
disposal operation is to be conducted, site
conditions, monitoring requirements,
and runoff water quality. One of the
purposes for disposal at this site was the
restoration of strip-mined land to agricul-
tural productivity. The crops grown are
limited by the EPA to animal feed.
Although the Sacramento site is not yet
in full-scale operation at the time of this
study, the planning process is well
documented. The site is subject to rules
from the State and County Departments
of Health and to orders from the Regional
Water Quality Control Board, which
dictate how sludge is to be handled. The
regulations require that the groundwater
be protected, that nuisance conditions
be minimized, and that there be no direct
surface runoff.
Conclusions and
Recommendations
1. No evidence was found of adverse
environmental impacts at the three
types of dedicated municipal sludge
application sites investigated. This
result strongly suggests that well-
managed sludge-application-to-
land projects can be environmentally
acceptable regardless of application
rate if properly sited, designed, and
operated.
2. The costs of the three types of OLD
sludge operation varied extremely
and were strongly influenced by
local conditions. No cost advantage
could be determined for any particu-
lar type of operation (Type I, II, or III)
based on the costs of the six sites
studied.
3. Selection of sludge management
options for any community should
be based on the relative information
available for that community. At
many of the sites, specific methods
of operation were dictated less by
cost than by social and aesthetic
issues. For example, the use of
sludge incorporation equipment at
the two Type III sites was dictated
by concern about odors and other
aesthetics. Sludge incorporation is
more aesthetically pleasing, because
the sludge applied cannot be seen
(as, for instance, in spray irrigation,
which is highly visible).
The full report was submitted in partial
fulfillment of Contract No. 68-03-3018 by
PEER Consultants, Inc., Rockville, Maryland
under the sponsorship of the U.S.
Environmental Protection Agency.
r U 8 GOVERNMENT FWNTlNa OFFICE 1«M- 559-111/10758
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LiliaA. Abron-Robinson and Leon W. Weinberger are with PEER Consultants, Inc.,
Rockville. MD 20852.
Gerald Sttrn is the EPA Project Officer (see below).
The complete report, entitled "Technical-Economic Study of Sewage Sludge
Disposal on Dedicated Land, "(Order No. PB 85-117 216; Cost: $14.50, 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:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PA
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
PS 0000329
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