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the farmers and to minimize need for environmental monitor-
ing. Application is at agronomic rates, usually on an annual
basis.
Chapter 7, Forest Land Application, can be limited by the N
need of the trees, i.e., application at silvaculture use
rates. Sludge is often applied only one time, or at multi-
year intervals, e.g., every 5 years, to a specific area.
t Chapter 8, Application to Disturbed Land for Reclamation, is
typically limited by the cumulative metals loadings. Usually
there is only one application to a site. In some cases,
nitrogen may be a factor to protect drinking water quality in
aquifers.
Chapter 9, Application to Dedicated Sludge Disposal Site, is
primarily limited by site-specific soils and hydrogeologic
conditions, climate, and vegetation (if grown). Usually
there are many sludge applications per year to the same site
area. Careful protection of ground water aquifers is a major
feature of these systems.
A limitation to all of the options is that sludge may contain materials
that are potentially harmful to surface waters, ground waters, and pub-
lic health. To avoid these problems, the site selection, design, and
management of land application systems require careful attention.
2.2 Agricultural Utilization
2.2.1 Purpose and Definition
Agricultural utilization of sludge is practiced in nearly every state,
and is especially common in New Jersey, Pennsylvania, Ohio, Illinois,
Michigan, Missouri, Wisconsin, and Minnesota. Hundreds of communities,
both large and small, have developed successful agricultural utilization
programs. These programs benefit the municipality generating the sludge
by providing an ongoing environmentally acceptable means of sludge dis-
posal, and provide the participating farmer with a substitute or supple-
ment for conventional fertilizers.
The agricultural utilization option assumes that the sludge is applied
at "agronomic rates," defined.as the annual rate at which the N and/or P
supplied by the sludge and available to the crop does not exceed the an-
nual N and/or P requirement of the crop. The amount of plant available
N or P applied to the site is based on that required by the crop. In
the case of N, the farmer would have applied this quantity of available
N as commercial fertilizer. By limiting N loadings to fertilizer recom-
mendations, the impact on ground water should then be no different from
normal agricultural operations. Chapter 6 of this manual provides de-
tails of agronomic rate calculations, limitations, etc.
2-4
-------
2.2.2 Advantages of Agricultural Utilization
Sludge contains several plant macronutrients, principally N and P, and
in most cases, significant amounts of micronutrients such as boron (B),
manganese (Mn), copper (Cu), molybdenum (Mo), and zinc (Zn). The exact
ratio of these nutrients will not be that of a well-balanced formulated
fertilizer; nevertheless, most agronomic crops respond favorably to the
nutrients in sludge.
Sludge may also be a valuable soil conditioner if added at rates greater
than agronomic rates. The addition of sludge to a ftne-textured clay
,soil can make the soil looser and more friable, and increase the amount
of pore space available for root growth and the entry of water and air
into the soil. In coarse-textured sandy soils, sludge,,can increase the
water-holding capacity of the soil, and provide chemical sites for nu-
trient exchange and adsorption.
The municipality(ies) generating the sludge may benefit, because, in
many cases, agricultural utilization is less expensive than alternative
methods of sludge management/disposal. The general public may benefit
from cost savings resulting to the municipality(ies) and the farmers
using the sludge. The recycling of nutrients is attractive to citizens
concerned with the environment, and resource conservation.
A major advantage of agricultural utilization is that usually the muni-
cipality does not have to purchase land. Further, the land utilized for
sludge application is kept in production. Its value for future uses is
not impaired, and it remains on the tax roles.
A final advantage is that agricultural utilization usually takes place
in a relatively rural setting. The sludge application operations are
similar to conventional farming operations, and are not likely to create
public complaints if properly managed.
2.2.3 Limitations and
Utilization
Potential Disadvantages of Agricultural
Sludge may contain constituents which are potentially harmful to the
crops themselves (phytotoxicity), or to animals and humans who consume
the crops. To avoid this problem, the quantity of sludge which may be
applied per unit of land area, both on an annual and cumulative basis,
should be controlled in accordance with regulatory limits or guidelines,
and good management practices, as detailed in Chapter 6. Cadmium (Cd),
a sludge constituent of widespread concern, has been extensively stud-
ied. Its application to cropland is regulated (see Chapters 4 and 6).
In general, municipalities which collect and treat substantial amounts
of industrial wastes from manufacturing industries may generate sludge
which contains relatively high levels of potentially harmful constitu-
ents. (See Appendix A for typical sludge characteristics.) These muni-
cipalities should carefully review the limitations placed on sludge ap-
plication to cropland (Section 6.4 of Chapter 6) before initiating an
agricultural utilization program.
2-5
-------
Sludge application rates for agricultural utilization (dry unit weight
of sludge applied per unit of land area) are usually relatively low.
Thus, large land areas may be needed, requiring the cooperation of many
individual land owners. In addition, the scheduling of sludge transport
and application scheduling for agricultural planting, harvesting, etc.,
plus adverse climatic conditions, will require careful management. If
the farms accepting sludge are numerous and widespread, an expensive and
complicated sludge distribution system may be required.
2.3 Application to Forest Lands
2.3.1 Purpose and Definition
Except for certain areas in the Great Plains and the southwest, forested
lands are abundant and well distributed throughout most of the United
States. Many major municipalities are located in close proximity to
forests; in fact, it is estimated that close to one-third of the land
within the standard metropolitan areas is forested. Furthermore, ap-
proximately two-thirds of all forest land in the United States is com-
mercial timberland (12). Thus, the application of sludge to forest
soils has the potential to be a major sludge utilization/disposal
option.
Unlike agricultural utilization, sludge application to forest lands is
not a common practice. In 1982, demonstration projects were ongoing in
several regions of the country (see Chapter 7). These demonstration
projects strongly indicate that forest application of sludge is a feasi-
ble option. However, the technical data base needed to design such
projects is incomplete. Users of this manual who are considering sludge
application to forest land are advised to contact the cities, agencies,
etc., listed in Chapter 7 to obtain updated information.
Three categories of forest lands may be available for sludge disposal:
Recently cleared land prior to planting.
Newly established plantations (about 3 to 10 years old).
t Established forests.
The availability of sites and the relative advantages and disadvantages
of each approach will determine which option or combination of options
is best for a given situation.
2.3.2 Advantages of Forest Land Utilization
Sludge contains nutrients and essential micronutrients often lacking in
forest soils. Demonstration projects have shown greatly accelerated
tree growth resulting from sludge application to both newly established
plantations and established forests. In addition, sludge contains or-
ganic matter which can improve the condition of forest soils by increas-
ing the permeability of fine-textured clay soil, or by increasing the
water-holding capacity of sandy soils.
2-6
-------
Since forests are not a food chain crop, there are fewer public health-
related concerns with the plant uptake of sludge constituents than with
agricultural use of sludge. In addition, research indicates that some
tree species are very tolerant to constituents in sludge (e.g., metals)
which ,may be harmful (phytotoxic) to certain agricultural crops.
Municipality(ies) located near forest lands may benefit, because forest
land utilization may be less expensive than alternate methods of sludge
management/disposal. The general public may benefit from cost savings
realized by the municipality(ies) and the commercial growers using the
sludge. The recycling of nutrients is attractive to environmentally
concerned citizens. For example, Seattle, Washington, is developing a
long-term program to apply sludge to forest lands in a systematic, well-
managed program. For Seattle, the proposed program appears to be the
least expensive method of sludge utilization/disposal, and has strong
public support. Since forests are perennial, the scheduling of sludge
applications is not as complex as it may be for agricultural utilization
programs when planting and harvesting cycles must be considered. In
some cases, the sludge application to forest soils may be a one-time ap-
plication, or applications may be scheduled at 3- to 5-year intervals.
A final advantage of forest land utilization is that the municipality
usually does not have to pay for acquiring land.
2.3.3 Limitations and Potential Disadvantages of Forest Land
Utilization
Since sludge application to forest lands is not widely practiced, the
designer of a proposed new program will probably have few regulations or
nearby existing similar programs to use for guidance. This information
gap may necessitate substantial preliminary effort with regulatory agen-
cies, forest land owners, and the general public to obtain approval for
a proposed new program.
It may be difficult to control public access to sludge-amended forest
lands. The public is accustomed to free access to forested areas for
recreational purposes, and may tend to ignore posted signs.
Control of public access is needed for up to 12 months
sludge is sprayed on forested areas. ,
fences, etc.
after liquid
Access into some forest lands may also be difficult for conventional
sludge application equipment. Terrain may be uneven and obstructed.
Access roads may have to be built and/or specialized sludge application
equipment used, or developed.
2.4 Application for Reclamation of Disturbed and Marginal Lands
2.4.1 Purpose and Definition
The surface mining of coal, exploration for minerals, generation of mine
spoils from underground mines, and tailings from mining operations have
2-7
-------
created over 1.5 million ha (3.7 million ac) of drastically disturbed
land. The properties of these drastically disturbed and marginal lands
vary considerably from site to site. Their inability to support vegeta-
tion is the result of several factors:
Lack of nutrients - The soils have low N, P, K, and/or micro-
nutrient levels.
Physical properties - Stony or sandy materials have poor
water-holding capacity and low cation, exchange capacity
(CEC). Clayey soils have poor infiltration, permeability,
and drainage.
t Chemical properties - The pH of mine soils, tailings, and
some drastically disturbed soils range from very acidic to
alkaline. Potentially phytotoxic levels of Cu, Zn, Fe, and
salts may be present.
Organic matter - Little, if any, organic matter is present.
Biological properties - Soil biological activity is generally
reduced.
Topography - Many of these lands are characterized by steep
slopes which are subject to excessive erosion.
Historically, reclamation of these lands is accomplished by grading the
surface to slopes that minimize erosion and facilitate revegetation. In
some cases, topsoil is,added. Soil amendments such as lime and fertili-'
zer are added, and grass, legumes, and/or trees are planted. Although
these methods are sometimes successful, numerous failures have occurred,
primarily because of the very poor physical, chemical, or biological
properties of these disturbed lands.
There have been a number of successful land reclamation projects involv-
ing the use of sludge or sludge compost. Most have been conducted on
strip-mined land or mine tailings in the Eastern coal states of Pennsyl-
vania, Illinois, Virginia, West Virginia, and Alabama. Projects in Ven-
ango, Somerset, Westmoreland, and Lackawanna Counties, Pennsylvania,
have involved reclamation of bituminous and anthracite strip-mine soil
banks with sludge or sludge compost. The soils were backfilled, recon-
toured without topsoil, and treated with lime to raise the pH to 7.
Sludge was applied at rates commensurate with the physical/chemical
characteristics of the mine soils and state guidelines.
Similar reclamation projects have been conducted at Fort Martin, West
Virginia; Contrary Creek, Virginia (abandoned pyrite mine tailings);
Fulton County, Illinois (Prairie project); and the Shawnee National For-
est (PALZO Tract), Illinois. No serious ground water degradation prob-
lems associated with sludge application has been documented at any of
these sites.
2-8
-------
Typically, sludge is applied only once to land reclamation project
sites. Therefore, an ongoing program of sludge application to disturbed
lands requires that a planned sequence of additional sites be available
for the life of the program. This objective may be achieved through ar-
rangements with land owners and mining firms active in the area, or
through the planned sequential rehabilitation of existing disturbed land
areas. In some cases, reclaimed areas may be used for agriculture pro-
duction using agronomic rates of sludge application.
2.4.2 Advantages of Utilizing Disturbed and Marginal Lands
This option may be extremely attractive in areas where disturbed and
marginal lands exist because of the dual benefit to the municipality in
disposing of its sludge, and to the environment through reclamation of
unsightly, largely useless land areas.
Sludges have several characteristics which make them suitable for re-
claiming and improving disturbed lands and marginal soils. One of the
most important is the sludge organic matter which (1) improves soil
physical properties by improving granulation, reducing plasticity and
cohesion, and increasing water-holding capacity; (2) increases the soil
cation exchange capacity; (3) supplies plant nutrients; and (4) in-
creases and buffers soil pH.
The natural buffering capacity and pH of most sludges will improve the
acidic or moderately alkaline conditions found in many mine soils. Im-
mobilization of heavy metals is pH-dependent, so sludge application re-
duces the potential for acidic, metal-laden runoff, and/or leachates.
Sludge is also desirable, because the nutrients contained therein may
substantially reduce commercial fertilizer needs. Furthermore, sludge
helps to increase the number and activity of soil microorganisms.
The amount of sludge applied in a single sludge application can often be
greater for land reclamation than for agricultural utilization, provided
that the quantities applied do not pose a serious risk of future plant
phytotoxicity or unacceptable nitrate leaching into a potable ground
water aquifer, and regulatory agency approval is granted. In some
cases, serious degradation of surface and ground water may exist at the
proposed site, and a relatively heavy sludge addition with subsequent
revegetation can be justified as improving an already bad situation.
The municipality usually does not have to purchase land for reclamation
projects. In addition, disturbed or marginal lands are usually located
in rural, relatively remote areas.
2.4.3 Limitations and Potential Disadvantages of Disturbed or
Marginal Land Reclamation
Plant species selected for use in revegetation should be carefully sel-
ected for their tolerance to sludge constituents and their suitability
to local soil and climate conditions. If crops intended for animal feed
or human consumption are planted, the same limitations (e.g., Cd) exist
as apply to agricultural utilization of sludge.
2-9
-------
Disturbed lands, especially old abandoned mining sites, often have ir-
regular, excessively eroded terrain. Extensive grading and .other site
preparation steps may be necessary to prepare the site for sludge appli-
cation. Similarly, disturbed lands often have irregular patterns of
soil characteristics. This may cause difficulties in sludge applica-
tion, revegetation, and future site monitoring.
Only a few states have developed specific regulations (e.g., Pennsyl-
vania, Illinois) or guidelines (e.g., New York) for sludge application
to disturbed or marginal lands. Therefore, many proposed new projects
may be faced with an extensive preliminary pioneering effort to obtain
regulatory agency approvals.
2.5 Dedicated Land Disposal
2.5.1 Purpose and Definition
The definition of a dedicated land disposal (OLD) site is less clear
than the other options described in the preceding sections. Generally,
a OLD project has the following characteristics:
The primary purpose is long-term sludge application, i.e., it
is a dedicated disposal site for landspreading of sludge.
Any additional site activities or benefits, such as the pro-
duction of agricultural crops or improvement of soil charac-;
teristics, are secondary to the sludge disposal activity.
Normally, sludge application rates are substantially higher
than for, other options, e.g., agriculture, forest, etc.
Obviously, higher application rates reduce the area of land
required.
t Usually, the municipality(ies) owns or has a long-term lease
on the land, which allows the,agency substantial discretion
in use of the land for sludge disposal purposes. .
Usually, the site needs to be more carefully designed, man-
aged, and monitored than sites where sludge is applied at
agronomic rates as a fertilizer amendment to cropland, forest
land, etc.
t Site design and operations are focused, upon containing any
environmentally detrimental sludge constituents within the
dedicated disposal site. Surface runoff, ground water leach-
ate, and harvested crops (if any) are carefully controlled.
Strict controls are virtually always required, and permitting
procedures often involve many agencies.
A special case included within the OLD site definition is when sludge is
applied to cropland at higher than agronomic rates (see Section 2.2.1
for definition of agronomic rates). Regulations generally require that
2-10
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projects involving sludge utilization at greater than agronomic rates
implement an extensive facility management plan to prevent adverse envi-
ronmental impacts, and impose restrictions on the end use of the crops
grown. In 1981, there were at least 20 operational OLD sites in the
United States.
2.5.2 Advantages of Dedicated Land Disposal
Generally, sludge is applied to OLD sites at high annual application
rates for many years; smaller land areas are thus required than for the
other land application options discussed in previous sections. Since
less land area is required, the municipality may be able to find a suit-
able site close to the POTW(s), thereby reducing sludge transport costs.
Pipeline transport of sludge in lieu of vehicle transport is often fea-
sible.
Sludge quality in terms of potential contaminant concentrations is usu-
ally less of a constraint with this option. Therefore, sludges which
are not of suitable quality for the other options may be acceptable for
OLD.
The municipality normally owns or controls the OLD site(s) under a long-
term lease. This eliminates the need for contractual arrangements with
privately owned farms, tree growers, mining operations, etc., usually
required by the alternative options. In addition, direct control of the
land allows much greater control of sludge application scheduling,
rates, and procedures. On-site construction (e.g., grading, drainage,
storage, fencing, roads, etc.) can be implemented to optimize future
operations without concern for its impact on a private owner. The muni-
cipality has the security of an assured long-term facility dedicated to
sludge disposal as its primary objective.
2.5.3
Limitations
Disposal
and Potential Disadvantages of Dedicated Land
Sludge application rates for OLD sites are usually much higher than
those required for vegetation growth and/or soil enhancement. There-
fore, sludge constituents accumulate at a higher rate on the site. This
requires:
t Generally, that the land must be purchased or leased, result-
ing in land costs to the municipality and probable removal of
the land from the tax rolls. Sometimes land condemnation
proceedings may be necessary to acquire an appropriate site.
Objections by neighboring property owners are also likely.
Sites be carefully designed, constructed, and managed to re-
tain on site the excess sludge constituents which could de-
grade the surrounding environment. Surface water runoff and
ground water leachate must usually be controlled, often by
construction of relatively expensive collection systems, re-
tention structures, etc.
2-11
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Buildup of metals, salts, etc., in the soil may make the OLD
site soil unsuitable for future use in agricultural produc-
tion, forestry, etc., because of phytotoxicity. Deed re-
strictions prohibiting future agriculture use of the site may
be required.
Regulatory agency requirements for monitoring of potential
ground water and surface water contamination are usually more
extensive than required for the other land application op-
tions.
Because large quantities of sludge are continually applied at a OLD
site, the potential is higher for nuisances such as odor, noise, dust,
and spills. A OLD site must generally be carefully located, managed,
and operated to avoid complaints by the public.
Permitting procedures may be complex and time-consuming, requiring ex-
tensive site investigations, design approvals, reporting to regulatory
agencies, and closure/post-closure plans.
2.6 Other Sludge Utilization Options
There are a number of sludge land application practices which have been
studied, but to date have not been used on a large scale. Several of
these options possess sludge utilization/disposal potential.
2.6.1 Turf Farms
The nutrients and soil amendment properties of sludge make it poten-
tially valuable and effective for use in sod production. One advantage
is that the organic N in sludge is released and becomes available for
plant growth over a relatively long period of time. This greatly re-
duces the amount and/or frequency of inorganic N application. Another
advantage is that turfgrass is a non-food chain crop; consequently,
heavy metal uptake is a lesser concern. In addition, turfgrasses are
generally more tolerant of soil heavy metal and salt concentrations than
many other crops.
The use of sludge in commercial sod production has great potential (29).
Dried or composted sludges provide an ideal growth medium for most turf-
grasses. Liquid sludges possess many of the same benefits, but are less
convenient to handle.
Seedling establishment is more rapid in composted sludge/soil mixtures
than with conventional sod seeding practices. Sod grown with sludge-
compost/soil mixtures weighs about 30 to 40 percent less than normal
soil sod (29, 31, 32). Hith surface application of composted sludge,
little or no herbicides are generally required. Liquid sludges often
contain viable seeds of undesirable plants, e.g., tomatoes, which will
require weed control.
2-12
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2.6.2 Parks and Recreational Areas
There have been two basic approaches to sludge use in parks and recrea-
tional' areas: (1) land reclamation followed by park establishment, and
(2) use of sludge as a substitute for conventional fertilizers in the
maintenance of established parkland vegetation. Sludge can supply a
portion 'Of the nutrients required to maintain lawns, flower gardens,
shrubs and trees, golf courses, recreational areas, etc. (19, 31, 32,
33, 34).
Although sludge use can be beneficial for park maintenance, there are a
number of disadvantages associated with its use:
Liquid sludge application may be odorous, and presents poten-
tial public health problems from sludge-borne pathogens.
The use of sludge on close-cut, highly maintained turf, such
as golf courses, may be aesthetically objectionable, because
of a black residue left on the surface of the sod.
Public relations problems dealing with popular misconceptions
and objections to sludge use in public places may develop.
All of the above-listed objections are significantly minimized if heat-
dried or composted sludge is used.
2.6.3 Highway, Airport, and Construction Site Landscaping
The construction of highways, airports, major buildings, shopping malls,
etc., frequently creates large areas of marginal, eroded, or generally
poor-quality soils. Landscaping is required to improveaesthetics and
control erosion. Sludge is an excellent soil conditioner and nutrient
source. All forms of sludge (i.e., liquid, dewatered, dried, or com-
posted) can be mixed with these soils before planting to provide a soil
environment suitable for vegetative growth. Sludges can also be used in
lieu of conventional fertilizers to provide many of the nutrients needed
to maintain the established vegetation (19, 31, 33, 34).
2.7 References
1. U.S. General Accounting Office. Sewage Sludge -- How Do We Cope
With It? Report to the Congress. CED-78-152, Washington, D.C.,
September 1978. 38 pp.
2. Galen, G. R. Federal Regulations for Municipal Sludge: Impact of
EPA Rules and Regulations on Land Application. In: National Con-
ference on Municipal and Industrial Sludge Utilization and Dis-
posal, Washington, D.C., May 1980. pp. 1-3.
2-13
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3. U.S. EPA. Sludge Treatment and Disposal, Vol.
012. Environmental Research Information Center.
October 1978. 155 pp. (Available from National
tion Service, Springfield, Virginia, PB-299 594)
4. California Department of Health. Consideration
stances in Sewage Sludge Added to Soil That Will
Crop: A Public Health Perspective. Sacramento,
pp.
2. EPA-625/4-78-
Cincinnati, Ohio,
Technical Informa-
of Chemical Sub-
Produce an Edible
March 1978. 230
5.
6.
7.
8.
CH2M Hill.
Wastewater
1976. 133
Biogro
Treatment
PP.
Program Organic Solids Reuse. Willow Lake
Plant, Salem, Oregon. Corvallis, Oregon, June
Braude, 6., G. P. Sagik, and C.
Using Sludge for Crops. Water
1978.
A. Sorber.
and Sewage
Human Health Risk of
Works, 125(2):62-64,
Pierce, R. 6. Sewage
8(6):6-10,144, 1977.
Sludge for Agricultural Use. Waste Age,
Hyde, H. C., A. L. Page, F. T. Bingham, and R. J.
of Heavy Metals in Sludge on Agricultural Crops.
Control Fed., 51:2475-2486, 1979.
Mahler. Effect
J. Water Pollut
9. Criteria for Classification of Solid Waste Disposal Facilities and
Practices. Federal Register, 44:53438-53468, September 13, 1979.
10. Decker, A. M., J. P. Davidson, R. C. Hammond, S. D. Mohanty, R. L.
Chaney, and T. S. Rumsey. Animal Performance on Pastures Top-
dressed with Liquid Sewage Sludge and Sludge Compost. In: Na-
tional Conference on Municipal and Industrial Sludge Utilization
and Disposal, Washington, D.C., May 1980. pp. 36-41.
11. Fitzgerald, P. R. An Evaluation of the Health of Livestock Exposed
to Anaerobically Digested Sludge from a Large Community. In: Na-
tional Conference on Municipal and Industrial Sludge Utilization
and Disposal, Washington, D.C., May 1980. pp. 32-36.
12. Smith, W. H., and J. 0. Evans. Special Opportunities and Problems
in Using Forest Soils for Organic Waste Application. In: Soils
for Management of Organic Wastes and Wastewaters. L. F. Elliott
and 0. F. Stevenson,-eds. Soil Science Society of America, Madi-
son, Wisconson, 1977. pp. 428-454.
13. Harris, A. R. Physical and Chemical Changes in Forested Michigan
Sand Soils Fertilized with Effluent and Sludge. In: Utilization
of Municipal Sewage Effluent and Sludge on Forest and Disturbed
Land. W. E. Sopper, and S. M. Kerr, eds. Pennsylvania State Uni-
versity Press, University Park, 1979. p. 155-161.
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14. Wooldridge, D. 0., and J. D. Stednick. Effects of Sludge Irriga-
tion on Three Pacific Northwest Forest Soils. EPA-600/2-80-002,
Municipality of Metropolitan Seattle, METRO, Washington. March
1980. 188 pp. (Available from National Technical Information Ser-
vice, Springfield, Virginia, PB80 204068)
15. Sidle, R. C. The Potential Use of Forest Land as a Sludge Disposal
Site. In: Food, Fertilizer and Agricultural Residues, Proceedings
of the 1977 Cornell Agricultural Waste Management Conference. R.
C. Loehr, ed. Ann Arbor Science, Ann Arbor, Michigan, 1977. pp.
199-215.
16. Stednick, J. D., and D. D. Wooldridge. Effects of Liquid Digested
Sludge Irrigation on the Soil of a Douglas Fir Forest. In: Utili-
zation of Municipal Sewage Effluent and Sludge on Forest and Dis-
turbed Land. W. E. Sopper, and S. N. Kerr, eds. Pennsylvania
State University Press, University Park, 1979. pp. 47-60.
17. Riekirk, H., et al. Effects of Dewatered Sludge Applications to a
Douglas Fir Forest Soil on the Soil, Leachate, and Groundwater Com-
position. In: Utilization of Municipal Sewage Effluent and Sludge
on Forest and Disturbed Land. W. E. Sopper,, and S. N. Kerr, eds.
Pennsylvania State University Press, University Park, 1979. pp.
35-45.
18. Edmonds, R. L., and D. W. Cole, eds. Use of Dewatered Sludge as an
Amendment for Forest Growth: Environmental, Engineering, and Econ-
omic Analyses. Bulletin Nos. 1-3. Center for Ecosystem Studies,
University of Washington, Seattle, April 1976-January 1980. 3 Vol-
umes.
Utilization of Municipal Sewage Effluent and Sludge on Forest and
Disturbed Land. W. E. Sopper, and S. N. Kerr, eds. Pennsylvania
State University Press, University Park, 1979. pp. 423-443.
Sopper, W. E., and S. N. Kerr. Revegetation of Mined Land Using
Wastewater Sludge. Public Works, 111(9):114-116, 1980.
Mathias, E. L., 0. L. Bennett, and P. E. Lundberg. Use of Sewage
Sludge to Establish Tall Fescue on Strip Mine Spoils in West Vir-
ginia. In: Utilization of Municipal Sewage Effluent and Sludge on
Forest and Disturbed Land. W. E. Sopper, and S. N. Kerr, eds.
Pennsylvania State University Press, University Park, 1979. pp.
307-314.
22. Stucky, D. J., and J. Bauer. Establishment, Yield, and Ion Accumu-
lation of Several Forage Species on Sludge-Treated Spoils of the
Palzo Mine. In: Utilization of Municipal Sewage Effluent and
Sludge on Forest and Disturbed Land. W. E. Sopper, and S. N. Kerr,
eds. Pennsylvania State University Press, University Park, 1979.
pp. 379-387.
19.
20.
21.
2-15
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23.
24.
25.
26.
Sopper, W.
Land Using
Conference
March 1979.
E., and S. N. Kerr.
Municipal Sludges.
on Municipal Sludge
pp. 228-237.
Criteria for Revegetation of Mined
In: Proceedings of 8th National
Management, Miami Beach, Florida,
Williams, B. D., and P. E. Packer. Sewage Sludge and Other Organic
Materials as Amendments for Revegetation of Spent Oil Shale. In:
Utilization of Municipal Sewage Effluent and Sludge on Forest and
Disturbed Land. W. E. Sopper, and S. N. Kerr, eds. Pennsylvania
State University Press, University Park, 1979. pp. 353-358.
U.S. EPA. Process Design Manual for Sludge Treatment and Disposal.
EPA-625/1-79-011, Center for Environmental Research Information,
September 1979. 1,135 pp. (Available from
Information Service, Springfield, Virginia, PB80
Cincinnati, Ohio,
National Technical
200546)
Sacramento Area Consultants. Sewage Sludge Management Program.
Volume I: SSMP Final Report, Work Plans, and Source Survey.
Sacramento Regional County Sanitation District, Sacramento, Cali-
fornia, September 1979. (Available from National Technical Infor-
mation Service, Springfield, Virginia, PB80 166739).
27. Brown and Caldwell. Preliminary Draft: Colorado Springs ,Long-
Range Sludge Management Study. City of Colorado Springs, Colorado,
April 1979.
28. Murray, J. J., J. C. Patterson, and D. J. Wehner. Use of Sewage
Sludge Compost in Turfgrass Production. In: National Conference
on Municipal and Industrial Sludge Utilization and Disposal, Wash-
ington, D.C., May 1980. pp. 66-70.
29. Abron-Robinson, L. A., C. Lue-Hing, and E. J. Martin. The Produc-
tion of Non-Food-Chain Crops Using Sewage Sludge: A Cost Compari-
son Analysis. . In: National Conference on Municipal and Industrial
Sludge Utilization and Disposal, Washington, D.C., May 1980. pp.
97-101.
30. Sopper, W. E., and S. N. Kerr. Mine Land Reclamation with Munici-
pal SludgePennsylvania's Demonstration Program. In: Reference
19. pp. 55-74.
31. Hornick, S. B., J. J. Murray, R. L. Chaney, L. J. Sikora, J. F.
Parr, W. D. Burge, 6. B. Will son, C. F. Tester. Use of Sewage
Sludge Compost for Soil Improvement and Plant Growth. USDA, Sci-
ence and Education Administration Agricultural Reviews and Manuals,
ARM-NE-6, August 1979. 10 pp.
32. Murray, J. J. Use of Composted Sewage Sludge in Turf Grass Produc-
tion. In: Proceedings of Waste Water Conference, Chicago, Illi-
nois. American Society of Golf Course Architects, November 1979.
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33. Sanderson, K. C.5 and W. C. Martin. 1974. Performance of Woody
Ornamentals in Municipal Compost Medium Under Nine Fertilizer
Regimes. Hort. Science, 9:242-243.
34. Annon. Using Municipal and Agricultural Waste for the Production
of Horticultural Crops. Proceedings of a Symposium, 1980. Hort.
Science, 15(a):161-178.
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CHAPTER 3
PUBLIC PARTICIPATION
3.1 Introduction
A community's willingness to cooperate with a sludge-to-land application
project varies with its perceptions of the project's potential benefits
and costs. For a land application project to gain public acceptance,
the community must determine that the benefits are greater than any pos-
sible or perceived burdens (e.g., odors, noise, truck traffic, etc.).
A major public acceptance barrier which has surfaced in many documented
case studies is the widely held perception that sludge is malodorous,
highly contaminated, and otherwise repulsive. Experience has shown that
such public apprehension can be partially allayed through public educa-
tion campaigns, adequate planning, and, most importantly, small demon-
stration or pilot programs (1).
Planning for public participation in a land application project involves
careful and early evaluation of who should be involved, to what degree,
and for what purpose. Clearly defined objectives will simplify deci-
sions, and will help to keep the program from becoming too diffused and
ineffective. The following discussion presents a summary of the major
considerations necessary to implement a successful program. A more de-
tailed discussion of public participation programs is presented in Ref-
erence (5). Potential mitigation of public acceptance problems is dis-
cussed in Reference (1).
3.1.1 Objectives
The major objectives of a public participation program include:
1. Providing the community with sufficient technical information
to clearly define the advantages and disadvantages of the pro-
posed project. Technical information should be presented in an
easily understandable manner to ensure communication between
the public, engineer, planner, consultant, regulatory, and
other officials.
2. Convincing landowners who are potential participants that it is
in their best interest to participate in the project.
3. Correcting any misinformation that exists within the community.
4. Keeping the community informed of plans as they develop.
5. Soliciting suggestions and support from both the proposed proj-
ect participants and their neighbors.
3-1
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Most programs will aim at the first of these objectives, and many will
pursue the second and third. The fourth and fifth objectives, taken in
conjunction with the first three, suggest a willingness to involve the
community, to listen to and use their suggestions, and to make the pub-
lic part of the planning team. The perspective of the engineering/plan-
ning team should be one of cooperation rather than confrontation.
3.1.2 Elements of Successful Public Involvement Programs
One should begin with the existing sludge management system and the need
to change it. Citizens should be told how the wastewater treatment pro-
cess functions, and what it means to the community. Sludge should be
defined, along with an explanation of where it originates and its compo-
sition and volume before and after treatment. Sludge management should
be related to the public's demand for clean water (2).
Agency and other project personnel should be trained in public contact.
Personnel should be well prepared to translate technical concepts into
simple, clear terms; they should also be prepared to deal with hostile
audiences. The attitudes displayed by project staff members do much to
create credibility or engender hostility.
The public's real concerns should be identified. Often, publicly ex-
pressed concerns mask the real reasons for opposition. For example,
property owners adjacent to a sludge application site may sound alarms
about ground water pollution when their major concern is actually prop-
erty value depreciation (2).
3.1.3 Participants
It is essential that a group of knowledgeable and enthusiastic resource
people participate in a land application program. This group should in-
clude the following participants (9):
University staff and federal and state experts who can provide
valuable research and technical information on land applica-
tion of sludge, and whose credibility usually reduces concern
and misunderstanding among concerned individuals or groups.
POTW managers and city officials who can provide background
information on municipal sludge problems.
Local or state cooperative extension staff who can assist in
the organizational aspects of community meetings.
Various agency personnel, including health officials, soil
conservation staff, state environmental protection staff,
etc., who will express their concerns and policies as they in-
fluence the design of a proposed project.
3-2
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Other local organizations/persons who should be involved in the develop-
ment of a land application project can include:
Recipients (e.g., farmers, tree growers, mine landowners,
etc.) who will use the sludge, and their neighbors.
Consulting engineers, and waste management firms.
Farming, forestry, mining, and other local organizations,
e.g., Farm Bureau, Soil and Water Conservation Districts.
Crop processors and produce users (via business, trade, and
consumer organizations).
News/communications media.
The actual project participants, whether on an active or an informa-
tional basis, will vary with the choice of land application option. In
each case, a broad spectrum of participants should be considered early
in the project. The number of participants can be narrowed later, as
necessary.
3.1.4 Methods
A number of methods are available for communicating the need for and
feasibility of a proposed project, and the technical information needed
to understand the project and to gain the support of individuals within
the community. Not all will be needed in all cases,
The information transfer process must address all of the advantages and
disadvantages of sludge use on land.Any potential problem which is not
publicly addressed at the outset of ,a project will likely be brought to
the attention of the media, resulting in the possible reduction of pub-
lic support and the Toss of the project leadership's credibility.
3.1.4.1 Formal Methods
Public hearings or meetings may be required and/or desirable
for most types of projects.
Workshops can bring together professional planners and public
officials with landowners and others who will be directly in-
volved. Specialized workshops, such as one involving land-
owners who have expressed tentative interest and others who
have already participated in a similar project, may be espe-
cially beneficial.
An Advisory Committee, composed of representatives from local
government, consumer/business organizations, environmental
protection organizations, processors, and planners, can be
useful for maintaining contact with both the general public
3-3
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and interested organizations. Such a committee should be
formed early in the planning stages. Its meetings should be
scheduled such that there is time for its views to be heard
and carefully considered before final decisions are made.
A mailing list is helpful for disseminating information as the
project proceeds. All interested persons and organizations
should be included. The list should be kept current, and a
continuing effort should be made to keep all who are inter-
ested informed.
Advertising and public relations techniques, such as press re-
leases, pamphlets, and brochures; and radio, television, or
newspaper feature stories and "advertisements.
3.1.4.2 Informal Methods
Open meetings, less structured than public hearings or work-
shops, can be held in conjunction with meetings of an Advisory
Committee or other interested organizations, such as the Town
Council, etc. These meetings provide a more relaxed forum for
the exchange of information and views. They also offer the
professional planner/engineer with an ideal opportunity to
listen to the community and to become aware of misinformation
which may exist concerning potential problems associated with
land application of sludge.
Personal contacts or interviews with potential participants
may be the most effective means of soliciting participation.
Contacts can be made in cooperation with local planners or
county extension agents who are already familiar with the com-
munity.
Demonstrations and field days can create opportunities for the
public to see sludge utilized as a resource. Allowing people
to see, feel, and smell treated, stabilized sludge can often
be good public relations.
Traveling displays can be set up to inform the public in a
visually interesting manner; these displays can be moved to
such locations as public libraries, shopping centers, etc.
(2).
3.1.5 Timing
A public participation program should begin very early in the develop-
ment of a proposed project, and should continue throughout the project.
All persons concerned should have the opportunity to express their views
before any decisions affecting the general public are made. They should
then be kept informed and involved throughout the course of the project.
3-4
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3.2 Public Participation Considerations Specific to Agricultural Utili-
zation
Project implementation requires acceptance and approval by local offi-
cials, farmers, landowners, and other affected parties. Public resis-
tance to agricultural utilization of sludge can stem from fear that the
sludge may contain concentrations of organic or inorganic substances
that could be toxic to plants, or accumulate in animals or humans con-
suming crops grown on sludge-treated lands.
The most critical aspect of the program is securing the involvement of
farmers who will utilize the ;sludge. How this involvement is to be
secured during the planning process depends on the individual communi-
ties' involved; their past experience with sludge application systems;
overall public acceptance of the concept; and the extent to which re-
lated or tangential environmental concerns are voiced in the community.
Generally, a low-key approach is most effective. The various approaches
can consist of one or more of the following steps:
Check with the POTW to
sludge in the past.
.see if any local farmers have requested
Have the local Soil Conservation Service or agricultural ex-
tension service agent poll various individuals in the area for
expressions of interest.
t Describe the project in the local newspaper, asking interested
parties to contact the extension agent.
Personally visit the identified parties and solicit their par-
ticipation. A telephone contact will elicit little support
unless followed by a personal visit.
The use of demonstration plots is very effective in promoting the utili-
zation of sewage sludge by farmers. If farmers can compare crops grown
on sludge-treated soil with these grown with conventional fertilizer,
their willingness to use sludge will increase markedly (3). The follow-
ing questions regarding sludge utilization need to be discussed with
landowners:
How long is the landowner
trial period of 1 or more
until one or both parties
period of time)?
willing to participate (e.g., a
years; open-ended participation;
decide to quit; for a prescribed
What crops are traditionally planted,
crop rotation?
and what is the usual
If the sludge characteristics were such that a different
is desirable, would the landowner be willing to plant
crop?
crop
that
3-5.
-------
Which
gram?
fields would be included in the sludge application pro-
Under what conditions would the landowner accept the sludge,
what time of the year, and in what quantities?
Is the landowner willing to pay a nominal fee for the sludge,
or accept it free of charge, or must the municipality pay the
landowner for accepting sludge?
Is the landowner willing to engage in special procedures,
e.g., maintaining soil pH at 6.5 or greater?
The public relations program should emphasize both the benefits and the
potential problems of applying sludge on cropland.
3.3 Public Participation Considerations Specific to Forest Utilization
No operational full-scale forest application programs in the United
States were identified at the time this manual was prepared in 1982,
although there were a few such programs planned for implementation in
the near future. Thus, proponents of a new program will have obvious
handicaps in gaining acceptance of new, relatively unproven sludge ap-
plication techniques. On the positive side, proponents can emphasize
the successful forest application demonstration projects listed in Table
7-1, and the basic similarities between forest application and agricul-
tural application.
To help achieve acceptance, a forest application program should satis-
factorily address the following questions:
How will public access be controlled in the application area
for an appropriate period (normally 12 to 18 months) after
sludge application? Forested areas are often used for various
recreational activities (e.g., picnicking, hiking, gathering
of forest products, etc.). Even privately owned land is often
viewed by the public as accessible for these purposes. The
owner of the land, private or public, will have to agree to a
method for controlling public access (e.g., fence, chain with
signs, etc.). The public, through its representatives, must
agree to restrictions if the land is publicly owned.
t Will public water supplies and recreational water resources be
adequately protected against contamination? This concern
should be covered by proper siting, system design, and moni-
toring. Public health authorities and regulatory agencies
must be satisfied and involved in the public participation
program. Careful consideration must be given to municipal
watersheds and/or drinking water recharge areas to avoid con-
tamination.
3-6
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Will the applied sludge cause adverse effects to the existing
or future trees in the application area? Based on the avail-
able data from research and demonstration projects, many tree
species, with few exceptions, respond positively to sludge ap-
plication, provided the sludge is not abnormally high in
detrimental constituents, and proper management practices are
followed.
Unlike most agricultural applications, there is much less con-
cern about possible food chain transmission of contaminants to
man. The consumption of wild animals by hunters and their
families will occur, but there is little potential for contam-
ination of meat from such animals through contact with a prop-
erly managed sludge application area.
3.4 Public Participation Considerations Specific to Disturbed Lands
Prior to the initiation of any reclamation project using sludge, it will
likely be necessary to educate the public to gain public acceptability.
The task may be difficult with lands disturbed by mining,, because local
opposition to mining activity already exists in many cases. This is
particularly true if the mining activity has already created some ad-
verse environmental problems, such as reduced local ground water qual-
ity, acid mine drainage, or serious soil erosion and sedimentation of
local streams.
Citizens, regulatory agencies, and affected private business entities
need to participate in the planning process from the beginning. The
most effective results are usually achieved when industry, citizens,
planners, elected officials, and state and federal agencies share their
experience, knowledge, and goals, and jointly create a plan acceptable
to all.
Participation of local advisory groups is helpful. This procedure was
used successfully, in developing the Pennsylvania program for using
sludge for reclamation of mined land. The Pennsylvania advisory group
was composed of farmers, elected officials, representatives from the
Soil Conservation District, Game Commission, Bureau of Forestry, the
County Extension Agent, and Community Resources Agents. This group met
quarterly with project personnel, and independently monitored several of
the pilot demonstration sludge projects over a 2-year period. The re-
sults of their independent monitoring study, which included analyses of
sludge delivered to several sites, vegetation, soils, and water, con-
vinced them that the concept was technically sound and environmentally
safe. All demonstrations were highly successful and paved the way for
public acceptance of full-scale operations which are now under way in
Pennsylvania.
Obviously, important participants are the owners of the disturbed land.
For a continuing program, it is usually necessary to make contractual
arrangements with the owner(s) to ensure that the areas of disturbed
3-7
-------
land needed for sludge application will be available during future years
of project operation.
3.5 Public Participation Considerations Specific to Dedicated Land
Disposal
Virtually all proposed dedicated land disposal (OLD) projects will
undergo an extensive public participation process. The project propo-
nents should show that the OLD option is the most suitable project
alternative in terms of economics^ technical feasibility, and environ-
mental impact.
Since OLD sites are normally intended for long-term use, adjacent prop-
erty owners will be particularly concerned about potential odors, patho-
gens, vectors, noise, dust, traffic, aesthetics, and other factors af-
fecting their quality of life and the resale value of their property.
Proper design and operational management will help to eliminate or mini-
mize these concerns. A large buffer area around the sludge application
area is usually desirable.
3.6 References
1. Deese, P. L., J. R. Miyares, and S. Fogel. Institutional Con-
straints and Public Participation Barriers to Utilization of Munici-
pal Wastewater and Sludge for Land Reclamation and Biomass Produc-
tion. A Report to the President's Council on Environmental Quality,
December 1980. 104 pp. (EPA 430/9-81-013; July 1981) MCD-81.
4.
5.
Gibbs, C. V. How to Build Support for Public Projects.
City and County, December 1982. pp. 38-42.
American
Miller, R. H., T. L. Logan, D. L. Forester, and D. K. White. Fac-
tors Contributing to the Success of Land Application Programs for
Municipal Sewage Sludge: The Ohio Experience. Presented at the
Water Poll. Control Fed. Annual Conference, Detroit, Michigan, Octo-
ber 4-9, 1981.
Sagik, B. P., B. E. Moore, and C. A. Sorber. Public Health Aspects
Related to the Land Application of Municipal Sewage Effluents and
Sludges. In: Utilization of Municipal Sewage Effluent and Sludge
on Forest and Disturbed Land. W. E. Sopper, and S. M. Kerr, eds.
Pennsylvania State University Press, 1979. pp. 241-263.
U.S. EPA. Process Design Manual for Municipal Sludge Landfills.
EPA 625/1-78-010, U.S. Environmental Protection Agency, Cincinnati,
Ohio, 1979.
3-8
-------
CHAPTER 4 . .
TECHNICAL ASSESSMENT AND PRELIMINARY PLANNING
4.1 General
The process of planning a sludge land application project begins with
the collection and assessment of basic data on sludge characteristics.
The sludge characteristics in conjunction with estimated application
rates can then be compared to applicable federal, state, and local regu-
lations for an initial assessment of sludge suitability for any of the
options discussed in Chapter 2. The public's perception and acceptance
of such a proposed project, as well as land availability, transportation
modes, and climatic conditions must all be considered and evaluated to
determine the feasibility of the proposed program.
Figure 4-1 presents a simplified flow diagram ,of the steps that should
typically be followed during the early planning phases of a proposed
project. This chapter addresses each of the sections shown on the flow
diagram. Additional sources of information which may be needed through-
out the various project planning and design phases are listed in Section
4.6 and 4.7.
4.2 Sludge Characterization
The
the
characterization of sludge properties is a necessary first step in
...... design of a land application system. Estimates of current and fu-
ture sludge quantities and quality are needed to determine land area re-
quirements, site life, application rates, storage facilities, and cost.
Information about the physical characteristics of sludge is needed to
select transportation and application methods. Chemical and biological
characterization is required to determine the suitability of sludge for
land application; the land application option(s) which may be appropri-
ate for utilization or disposal; appropriate sludge application rates;
and monitoring parameters. Consideration should be given to the feasi-
bility of future changes in sludge processing and/or system design which
would make the sludge more desirable for a land application option.
Appendix A provides detailed information about sludge characteristics;
Appendix C summarizes sludge sampling and analytical procedures.
4.2.1 Physical Characteristics of Sludge
The physical characteristics of interest are solids content, expressed
as percent solids. This affects the potential land application system
design since:
The higher the sludge solids content, the,lower the volume of
sludge that will have to be transported, stored, etc., be-
cause less water must be handled.
4-1
-------
DETERMINE SLUDGE CHARACTERISTICS;
CHEMICAL, BIOLOGICAL AND PHYSICAL
(SECTION 4.2)
I
REVIEW APPLICABLE REGULATIONS AND
GUIDELINES FOR LAND APPLICATION OF
SLUDGE, FEDERAL, STATE AND LOCAL
(SECTION 4.3)
1
COMPARE SLUDGE CHARACTERISTICS TO
REGULATORY REQUIREMENTS AND EVALUATE
SUITABILITY OF SLUDGE FOR A LAND
APPLICATION OPTION (CHAPTER 5)
ESTIMATE LAND AREA REQUIRED FOR
SLUDGE APPLICATION, AND AVAILABILITY
OF LAND AREA NECESSARY
(SECTION 4.4)
I
ASSESS SLUDGE TRANSPORT MODES
AND THEIR FEASIBILITY
(SECTION 4.5)
Figure 4-1.
Simplified planning .steps for a sludge land
application option.
4-2
-------
The type of transport which can be utilized, e.g., truck
type, feasibility of pipeline transport, etc. (see Chapter 10
for discussion).
t The method of sludge application and sludge application
equipment needed, e.g., type of sludge application vehicle,
need for incorporating the sludge into the soil, etc.
The methods available to transfer and store sludge.
In general, it is less expensive to transport sludge which has a high
solids content, i.e., dewatered sludge, than sludge with a low solids
content, i.e., liquid sludge. This cost savings in sludge transport
should be weighed against the cost of dewatering the sludge.
Typically, liquid sludge has a solids content of 2 to 10 percent solids,
and dewatered sludge has a solids content of 20 to 40 percent solids,
which includes the chemical additives. Dried or composted sludge typi-
cally has a solids content over 50 percent.
4.2.2 Chemical Characteristics of Sludge
The chemical composition of sludge varies greatly between sewage treat-
ment plants (POTW's); also over time from a single POTW. Sludge compo-
sition depends principally on the characteristics of the raw sewage in-
fluent entering the POTW and the treatment processes used. It is gener-
ally true that the more industrialized a community is, the greater the
possibility that heavy metals and persistent organics will be a poten-
tial problem for land application of sludge.
Routine sludge analyses for land application purposes should include
total N, ammonia N, total P, K, Cu, Zn, Pb, Cd, and Ni. Other parame-
ters which should be analyzed for, at least initially, to screen for
abnormal sludge characteristics are Cr, B, As, Al, Co, Mo, sulfate, and
PCB's. If the presence of relatively high concentrations of other pri-
ority pollutants is suspected, e.g., halogenated hydrocarbons, polynu-
clear aromatic compounds, etc., then these parameters should also be
measured.
Table 4-1 presents concentrations of macronutients (N, P, K), heavy met-
als of primary concern, and PCB's in sludges from several sources (see
more complete sludge composition data). The degree of
the individual components should be noted. The data
4-1 and Appendix A are intended primarily for illustra-
While the data are useful in preliminary planning, anal-
ysis of the actual sludge to be land-applied is necessary for design
purposes. As discussed in Appendix A, many sludges show a wide varia-
tion in composition over time. Thus, it may be necessary to analyze a
substantial number of sludge samples over a period of 2 to 6 months or
longer to provide a reliable estimate of sludge composition.
\
Appendix A for
variability of
shown in Table
tive purposes.
4-3
-------
TABLE 4-1
CHEMICAL COMPOSITION OF SEWAGE SLUDGES (2)(3)'
Component
Total N
NH4*-N
N03"-N
P
K
Cu
Zn
Ni
Pb
Cd
PCB's
Number
of
Samples
191
103
43
189
192
205
208
165
189
189
14
Range
<0.1-17.6
5xlO-4-6.76
2xlO'4-0.49
<0. 1-14.3
0.02-2.64
84-10,400
101-27,800
2-3,520
13-19,700
3-3,410
<0. 01-23.1
Median
f ppprpni" ^ '
3.30
0.09
0.01
2.30
0.30
fmn/\tn^}
^my/sg ; - - -
850
1,740
82
500
16
3.90
Mean
3.90
0.65
0.05
2.50
0.40
1,210
2,790
320
1,360
110
5.15
* Data are from numerous types of sludges (anaerobic, activated
sludge lagoon, etc.) in 15 states: Michigan, New Hampshire,
New Jersey, Illinois, Minnesota, and Ohio (2); California,
Colorado, Georgia, Florida, New York, Pennsylvania, Texas, and
Washington (3); and Wisconsin (2)(3).
t Oven-dry solids basis.
The chemical characterization of the sludge affects the following design
decisions:
Whether the sludge can be cost-effectively applied to land.
Which land application options are technically feasible.
t The quantity of sludge which can be applied per unit area of
application site, both annually and cumulatively.
The degree of regulatory control and system monitoring re-
quired.
4-4
-------
4.2.3 Biological Characteristics
A detailed discussion of pathogens which may be present in sludge is
provided in Appendix A. Generally, sludge intended for land application
must be stabilized by chemical or biological processes. Stabilization
greatly reduces odor potential and the number of pathogens in sludge,
including bacteria, parasites, protozoa, and viruses (4). Nevertheless,
most stabilized sewage sludge will still contain some pathogens, and
safeguards are necessary to protect against possible contamination of
operating personnel, the general public, and crops intended for human
consumption. Usually, sludge biological characteristics are not di-
rectly analyzed, and the project designer relies on recommended opera-
tional controls and procedures to assure adequate pathogen reduction.
4.2.4 Data Sources
The wastewater treatment plant represents the most likely source of
sludge data. If data have not been collected, a procedure for sampling
and analyzing should be instituted to assure that representative data
are obtained, as discussed in Section 11.4.2 and Appendix C.
4.3 Regulations and Guidelines
Land application of sludge may be regulated by federal, state, and local
governments. Federal legislative authority for regulating land applica-
tion of sludge is vested in the EPA by the Resource Conservation and
Recovery Act of 1976 (RCRA) and the Clean Water Act of 1977 (CWA). Under
this authority, the EPA promulgates and enforces regulations and guide-
lines which represent acceptable practices. The individual states have
the responsibility of developing programs to implement these regulations
and guidelines. In addition, some state and local governments have de-
veloped more stringent regulations (5). Some of the regulatory agencies
which may have jurisdiction over municipal sludge land application pro-
grams are shown in Figure 4-2.
It
It
is beyond the scope of this manual
is, therefore, necessary for the
current regulations with
to detail all current regulations.
system planner/designer to review
the cognizant regulatory and permitting agen-
area, state, and/or region where the proposed project
the local
located.
For preliminary guidance, a brief summary of some of the possible con-
straints applicable to a proposed land application project are presented
below.
4.3.1 Floodplains
Land application sites generally should not be located where the land
will be flooded, resulting in washout of the applied sludge from the ap-
plication area. Appropriate construction of berms, dikes, channels,
4-5
-------
AGENCIES WITH JURISDICTION OVER LAND APPLICATION
.OFFICE OF WATER PROGRAMS
OPERATIONS CONSTRUCTION
GRANTS
NATIONAL'
EPA
FEDERAL
REGIONAL-
OFFICE OF SOLID WASTES
ENFORCEMENT POLICY
CONSTRUCTION GRANTS REVIEW
SOLID WASTE PROGRAM REVIEW
ENFORCEMENT
OFFICE OF SURFACE MININGNATIONAL GUIDELINES
STATE
WASTEWATER PROGRAMS
ENVIRONMENTAL QUALITY (SURFACE WATER,
GROUND WATER, SOILS, ETC.)
SOLID WASTE MANAGEMENT
PUBLIC HEALTH
AGRICULTURE
TRANSPORTATION
LOCAL
(RECEIVING
COMMUNITY)
LAND USE
ONSERVATION/ENVIRONMENTAL QUALITY
PUBLIC HEALTH
SOLID WASTE MANAGEMENT
Figure 4-2. Institutional framework (Ref. 5)
4-6
-------
etc.,
ever,
can be implemented to protect against flooding, if necessary; how-
increased costs are involved.
4.3.2 Surface Waters
The land application project should not cause unacceptable discharge of
sludge pollutants into surface waters. In general, land application
sites should be designed to prevent excessive surface runoff reaching
rivers, streams, and lakes. If runoff is likely to be a problem, then
appropriate controls should be employed to protect surface waters from
either point source or non-point source pollution from a sludge land ap-
plication site. Sludge soil incorporation practices can help to miti-
gate the potential for surface water runoff.
4.3.3 Ground Water
The land application project should not contaminate an existing or po-
tential underground drinking water source (potable water aquifer) beyond
the application site boundary. However, a state with a solid waste man-
agement plan approved by the EPA may establish an alternative boundary
to be used in lieu of the application site boundary. A state may spe-
cify such a boundary only if it finds that such a change would not re-
sult in contamination of ground water which may be needed or used for
human consumption. This finding is to be based on analysis and consid-
eration of al1 of the following factors:
Hydrogeological characteristics of the facility and surround-
ing land.
Volume and physical and chemical characteristics of the
leachate.
Quantity, quality, and directions of ground water flow.
Proximity and withdrawal rates of ground water users.
Availability of alternative drinking water supplies.
Existing quality of the ground water, including other sources
of contamination and their cumulative impacts on the ground
water.
Public health, -safety, and welfare considerations.
In essence, the project designer must show that either the leachate from
the sludge disposal site will not contaminate the adjacent underlying
ground water, or that it is of no significance since the ground water
affected is not useful now or in the future (i.e., excluded aquifer).
As explained in Chapters 6, 7, and 8, most states will accept applica-
tion of sludge at agronomic rates as evidence that ground water contami-
nation will not occur.
4-7
-------
4.3.4 Odors and Air Quality
Generally, permit conditions will require that land application projects
do not create nuisance odors beyond the application site boundary. How
this is determined (measured) varies, depending on the regulatory agency
and the proximity of the application site to public use areas. In addi-
tion, when liquid sludge is sprayed on the application site, it is usu-
ally a requirement that the public not be exposed to aerosols, created
by the sludge application.
4.3.5 Public Access
Land application sites are generally required to limit exposure of the
public to any potential health and safety hazards. The extent to which
public access should be limited depends on (1) the degree to which the
sludge has been treated to reduce pathogens (see Section 4.3.6), (2) the
procedures used to apply and incorporate the sludge into the soil, (3)
the remoteness of the sludge application site from public use areas, and
(4) the ownership of the sludge application site area, whether private
or public. In general, if there is an aspect of the operation that
could expose the public to potential health and safety hazards, then
fences or some other positive means of controlling public access is
needed.
4.3.6 Sludge Treatment for Pathogen Reduction
Interim,
that the
.11
final federal regulations (issued in September 1979) require
sludge be treated by a "process to significantly reduce patho-
gens" prior to land application. The processes considered satisfactory
to meet this requirement are the standard sludge stabilization pro-
cesses, such as aerobic digestion, anaerobic digestion, air drying beds
for at least 3 months, composting, and lime stabilization. Since these
stabilization processes generally do not sterilize the sludge, the fed-
eral regulations require that public access be controlled for at least
12 months after sludge application, and that grazing by animals whose
products are consumed by humans be prevented for at least 1 month after
sludge application.
Crops for direct human consumption are a special case. If there is
direct contact between the sludge and the edible portion of a crop grown
for direct human consumption, federal regulations require that at least
an 18-month period must elapse between the sludge application and grow-
ing of such crops, or that the sludge be subjected to further disinfec-
tion treatment prior to application. Disinfection treatment processes
may include composting, heat drying, heat treatment, thermophilic aero-
bic digestion, pasteurization, and irradiation.
4.3.7 Sludge Application to Land Used for the Production of Food
Chain Crops
The federal regulations cited above also include interim limits on Cd
and PCB's, and set a minimum soil pH for soils used for sludge
4-8
-------
application which produce food chain crops. In 1982, additional guid-
ance was issued by EPA/USDA/FDA for the use of sludge in the production
of fruits and vegetables. (See Table 4-2 for a summary.) Chapter 6
discusses these limits in detail.
TABLE 4-2
SUMMARY OF JOINT EPA/FDA/USDA GUIDELINES FOR SLUDGE
APPLICATION FOR FRUITS AND VEGETABLES PRODUCTION (7)
Annual and Cumulative Cd Rates
Annual rate should not exceed 0.5 kg/ha. Cumulative Cd loadings should not
exceed 5, 10, or 20 kg/ha, depending on soil pH and CEC values of <5, 5 to 15,
and >15 meq/100 g, respectively.
Soil pH (plow zone - top 6 in) should be 6.5 or greater at time of each s.ludge
application.
PCB's
Sludges with PCB concentrations greater than 10 mg/kg should be incorporated
into the soil.
Pathogen Reduction
Sludge should be treated by pathogen reduction process before soil applica-
tion. Waiting period of 12 to 18 months before a crop is grown may be re-
.quired, depending on prior sludge processing and disinfection.
Use of High-Quality Sludge
High-quality sludge should not contain more than 25 mg/kg Cd, 1,000 mg/kg Pb,
and 10 mg/kg PCB (dry weight basis).
Cumulative Lead Application Rate . . . .
Cumulative Pb loading should not exceed 800 kg/ha.
Pathogenic Organisms
A minimum requirement is that crops to be eaten raw should not be planted in
sludge-amended fields within 12 to 18 months after the last sludge applica-
tion. Further assurance of safe and wholesome food products can be achieved
by increasing the time interval to 36 months.
Physical Contamination and Filth
Sludge should be applied directly to soil and not directly to any .human food
crop. Crops grown for human consumption on sludge-amended fields should be
processed with good food industry practices, especially for root crops and
low-growing fresh fruits and vegetables.
Soil Monitoring
Soil monitoring should be performed on a regular basis, at least annually for
pH. Every few years, soil tests should be run for Cd and Pb.
Choice of Crop Type
The growing of plants which do not accumulate heavy metals is encouraged.
4-9
-------
4.3.8 Sludge Classified as Hazardous Hastes
In rare cases, a specific sludge may be so high in metal or organic con-
taminants that it would be classified as a hazardous waste under Subti-
tle C of RCRA. If the sludge being considered for land disposal or
utilization is extraordinarily high in one or more of the priority pol-
lutants (see Appendix A for typical sludge quality ranges), then the
planner/designer should check the RCRA hazardous waste regulations. If
a specific sludge is found to be a hazardous waste under RCRA defini-
tion, it must be disposed of at an acceptable hazardous waste facility."
The summary of regulations and guidelines provided in this manual is not
intended to be complete; it also may not be current at the time that
this manual is in general use. All current federal, state, and local
regulations and guidelines should be reviewed during preliminary plan-
ning.
4.3.9 Possible Permits Required
The project designer should investigate pertinent regulations early in
the,planning for planned sludge land application projects. Depending on
local procedures, permits may be required from both state and local reg-
ulatory agencies.
As in all cases where regulations are promulgated by more than one
agency within the same jurisdiction, the most stringent rule must be
followed in each case. It is therefore essential that the designer be
aware of state regulations concerning the facility or practice, as well
as any local regulations (county, municipal, or regional).
4.4 Estimate of Land Area Requirement
A precise estimate of the land area required for sludge application
should be based on design calculations provided in Chapters 6, 7, 8, and
9 for the land application option(s) under consideration. However, for
preliminary planning, a rough estimate of the land application area
which might be necessary can be obtained from Table 4-3. (Note that the
options may not necessarily involve repeated annual applications.)
As an example, assume that the project is intended to dispose 1,000 mt
(1,100 T), dry weight, of sludge annually. Using the typical rates
shown in Table 4-3, a very rough estimate of the area required for agri-
cultural utilization would be 90 ha (220 ac), plus additional area re-
quired, if any, for buffer zones, sludge storage, etc. For the same
quantity of sludge utilized for land reclamation, the typical values
shown in Table 4-3 indicate that 9 ha (22 ac) would be required each
year that the reclamation program is in operation.
4-10
-------
TABLE 4-3
ESTIMATED SLUDGE APPLICATION IN DRY WEIGHT FOR DIFFERENT
LAND DISPOSAL OPTIONS
Disposal Option
Agricultural Utilization
Forest Utilization
Land Reclamation Utilization
Dedicated Disposal Site
Time Period of
Application
Annual
One time, or at
3-5 year intervals
One time
Annual
Reported Range of
Application Rates
mt/ha
Z-70
10-220
7-450
220-900
T/ac
1-30
4-1-00
3-200
100-400
Typical Rate
mt/ha
11
44
112
340
T/ac
5
20
50
150
Note: The rates shown are only for the sludge application area, and do not include
area for buffer zone, sludge storage, or other project area requirements.
4.5 Transportation of Sludge
Chapter 10 of this manual discusses sludge transportation alternatives
and costs. Transport can be a major cost of a land application system,
and requires a thorough analysis. This section is intended only to pro-
vide a brief summary of the alternatives which may be considered during
the preliminary planning phase.
The first consideration is the nature.of the sludge itself. As shown in
Table 4-4, sewage sludge is classified for handling/transport purposes
as either liquid, sludge cake, or dried, depending upon its solids con-
tent. Only liquid sludge can be pumped and transported ,by pipeline. If
liquid sludge is transported by truck, rail, or barge, closed vessels
must be used, e.g., tank truck, railroad tank cars, etc. Sludge cake
can be transported in watertight boxes, and dry sludge can be trans-
ported in open boxes (e.g., dump trucks).
TABLE 4-4
SLUDGE SOLIDS CONTENT AND HANDLING CHARACTERISTICS
Sludge Type
Liquid
Sludge cake
("wet" solids)
Dried
Typical
Solids Content (%)
1 to 10
15 to 30
50 to 95
Handling/
Transport Methods
Gravity flow, pump,
pipeline, tank trans-
port
Conveyor, auger, truck
transport (watertight
box)
Conveyor, bucket, truck
transport (box)
4-11
-------
There are four basic modes of sludge transport: truck, pipeline, barge,
and railroad. In certain instances, combined transport methods (e.g.,
pipeline-truck, pipeline-barge) are also used. Some practical consid-
erations of hauling sludge are presented in Tables 4-5, 4-6, and 4-7.
staffing needs,
For a detailed
A rating of transport modes in terms of reliability,
energy requirements, and costs is given in Table 4-7.
discussion of sludge transport, see Section 10.2.
4.6 Climate
Analysis of climatological data is an important consideration for the
preliminary planning phase. Rainfall, temperature, evapotranspiration,
and wind may be important climatic factors affecting land application of
sewage sludge, selection of land application option, site management,
and costs. Table 4-8 highlights the potential impacts of some climatic
regions on the land application of sludge.
Meteorological data are available for most major cities from three pub-
lications of the National Oceanic and Atmospheric Administration (NOAA):
t The Climatic Summary of the United States.
The Monthly Summary of Climatic Data, which provides basic
data, such as total precipitation, maximum and minimum tem-
peratures, and relative humidity for each day of the month,
and for every weather station in the same given area. Evapo-
ration data are also given, where available.
t Local Climatological Data, which provides an annual summary
with comparative data for a relatively small number of major
weather stations.
This information can be obtained by written request to NOAA, 6010 Execu-
tive Boulevard, Rockville, Maryland 20852. Another excellent source is
the National Climatic Center in Asheville, North Carolina 28801.
Weather data may also be obtained from local airports, universities,
military installations, agricultural and forestry extension services,
agricultural and forestry experiment stations, and agencies managing
large reservoirs.
4.7 Sources of Additional Information
Additional sources of information on land characteristics, cropping pat-
terns, and other relevant data include:
t U.S. Department of Agriculture - Agricultural Stabilization
and Conservation Service, Soil Conservation Service, Forest
Service, and Extension Service.
4-12
-------
TABLE 4-5
TRANSPORT MODES FOR SLUDGES
Sludge Type
Liquid Sludge
Rail Tank Car
Sarge
Pipeline
Vehicles
Tank Truck
Farm Tank Wagon
and Tractor
Transportation Considerations
100-wet-ton (24,000-gal) capacity; suspended solids
will settle while in transit.
Capacity determined by waterway; Chicago has used
1,200-wet-ton (290,000-gal) barges. Docking facili-
ties required.
Need minimum velocity of 1 fps to keep solids in
suspension; friction decreases as pipe diameter
increases (to the fifth power); buried pipeline
suitable for year-round use. High capital costs.
Capacity - up to maximum load allowed on road, usually
6,600 gal maximum. Can have gravity or pressurized
discharge. Field trafficability can be improved.by
using flotation tires" at the cost of rapid tire wear
on highways.
Capacity - 800 to 3,000 gal.
for field application.
Principal use would be
Semi sol id or Dried Sludge
Rail Hopper Car
Truck
Farm Manure Spreader
Need special unloading site afld equipment for field
application.
Commercial equipment available to unload and spread on
ground; need to level sludge piles if dump truck is
used. Spreading can be done by farm manure spreader
and tractor.
TABLE 4-6
AUXILIARY FACILITIES FOR TRANSPORT (11)
Truck
Transport Mode
Railroad
Loading storage . No* Yes Yes . Yes
Loading equipment ' Yes Yes Yes Yes
Dispatch office Yes Yes Yes NAt
Dock and/or control building NA NA Yes Yes
Railroad siding(s) NA Yes NA NA
Unloading equipment Yes Yes Yes NA
Unloading storage* No Yes Yes Yes
Dewatered
Loading storage Yes** Yes NA NA
Loading equipment Yes Yes NA NA
Dispatch office Yes Yes NA NA
Dock and/or control building NA NA NA NA
Railroad siding(s) NA Yes NA NA
Unloading equipment Yes Yes NA NA
Unloading storage No No NA NA
* Storage required for one or two truckloads is small compared with normal
plant sludge storage.
t Not applicable.
# Storage assumed to be a part of another unit process.
** Elevated storage for ease of gravity transfer to trucks.
4-13
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TABLE 4-7
EVALUATION OF SLUDGE TRANSPORT MODES (11)
Transport Mode Alternatives
Characteristics
Reliability and Complexity*
Staffing Skills*
Staff Attention (T1me)#
Applicability and Flexibility
Energy Used**
Costs
Capital Investment
Operation, Maintenance, and
Overall**
Truck/Barge
2
3
4
3
7
High
Labor High
--
Pipe/Barge
2
3
3
3
3
High
Moderate
Barge
3
3
4
3
5
High
Moderate
--
Railroad
1
2
1
2
2
_
-
Generally
High***
Truck
1
1
3
1
8
Low
Fairly High
--
Pipeline
3
3
2
3
6
High
Low
* 1 = most reliable, least complex; 2 = intermediate; 3 - least reliable, most complex.
t 1 « least skills; 2 = intermediate; 3 = highest skills. '
I Attention time Increases with magnitude of number.
** 1 » wide applicability (all types of sludges); 3 = limited applicability, relatively flexible.
It 1 - lowest; 8 = highest.
II Overall costs are a function of sludge quantities and properties (percent solids), distance transported,
and need for special storage loading and unloading equipment.
*** Rail costs would generally be in the form of freight charges; costs could be lower for large volumes
of sludge.
TABLE 4-3
POTENTIAL IMPACTS OF CLIMATIC REGIONS ON
LAND APPLICATION OF SLUDGE (11)
Climatic Region
Impact
Operation Time
Operation Cost
Storage Requirement
Salt Buildup Potential
Leaching Potential
Runoff Potential
Warm/Arid
Year-round
Lower
Less
High
Low
Low
Warm/Humid
Seasonal
Higher
More
Low
High
High
Co Id/ Hum id
Seasonal
Higher
More
Moderate .
Moderate
High
4-14
-------
U.S. Geological Survey.
U.S. EPA.
U.S. Corps of Engineers offices.
Private photogrammetry and mapping companies.
State agricultural mining and geologic agencies.
0 State water resources agencies.
State universities and local colleges.
t Local planning and health departments.
* Local water conservation districts.
Ground water users (municipalities, water companies, individ-
uals, etc.).
State land grant universities and water resource centers.
4.8 References
1. McCalla, T. M., J. R. Peterson, and C. Lue-Hing. Properties of
Agricultural and Municipal Wastes. In: Soils for Management of
Organic Wastes and Waste Waters. Elliott, L. F., et al., eds.
Soil Science Society of America, Madison, Wisconsin. 1977. pp.
11-43.
2. Sommers, L. E. Chemical Composition of Sewage and Analysis of
Their Potential Use as Fertilizers. J. Environ. Qual., 6:225-232.
1977.
3. Furr, A. K., A. W. Lawrence, S. S. C. long, M. C. Grandolfo, R. A.
Hofstader, C. A. Bache, W. H. Gutenmann, and D. J. Lisk. Multi-
element and Chlorinated Hydrocarbon Analysis of Municipal Sewages
of American Cities. Environ. Sci. Techno!., 10:683-687. 1976.
4. Sagik, B. P., B. E. Moore, and C. A. Forber. Public Health Aspects
Related to the Land Application of Municipal Sewage Effluents and
Sludges. In: Utilization of Municipal Sewage Effluent and Sludge
on Forest and Disturbed Land. W. E. Sopper, and S. M. Kerr, eds.
Pennsylvania State University Press, University Park, 1979. pp.
241-263.
5. Deese, P. L., J. R. Miyares, and S. Fogel; Institutional Con-
straints and Public Acceptance Barriers to Utilization of Municipal
Wastewater and Sludge for Land Reclamation and Biomass Production;
A Report to the President's Council on Environmental Quality. EPA
4-15
-------
430/9-81.
MCD-81.
December 1980. 104 pp. (EPA 430/9-81-013; July 1981)
6. Criteria for Classification of Solid Waste Disposal Facilities and
Practices (40 CFR, Part 257), Federal Register, 44:55438-53468,
September 13, 1979. 31 pp.
7. Land Application of Municipal Sewage Sludge for the Production of
Fruits and Vegetables; A Statement of Federal Policy and Guidance.
SW-905, U.S. Environmental Protection Agency, 1981. 25 pp.
8. U.S. EPA. Process Design Manual: Municipal Sludge Landfills. EPA
625/1-78-010, SCS Engineers, Reston, Virginia, October 1978. 331
pp. (Available from National Technical Information Service,
Springfield, Virginia, PB-299 675)
9. Miller, R. H., T. L. Logan, D. L. Forester, and D. K. White. Fac-
tors Contributing to the Success of Land Application Programs for
Municipal Sewage Sludge: The Ohio Experience. Presented at the
Water Pollution Control Federation, Detroit, October 1981.
10. Eckenfelder, W. W., Jr., and C. J. Santhanam, eds. Sludge Treat-
ment. Marcel Dekker, New York, 1981. 617 pp.
11. Culp, G. L., J. A. Faisst, D. J. Hinricks, and B. R. Winsor. Evalu-
ation of Sludge Management Systems: Evaluation Checklist and Sup-
porting Commentary. EPA 430/9-80-001, Culp/Wesner/Culp, El Dorado
Hills, California, February 1980. 248 pp. (Available from Na-
tional Technical Information Service, Springfield, Virginia, PB81
108805)
12. Knezek, B. D., and R. H. Miller, eds. Application of Sludges and
Wastewaters on Agricultural Land: A Planning and Educational
Guide. North Central Regional Research Publication No. 235. Ohio
Agricultural Research and Development Center, Wooster, 1976. 88
pp.
13. U.S. EPA. Principles and Design Criteria for Sewage Sludge Appli-
cation on Land. In: Sludge Treatment and Disposal. Vol. 2. EPA-
625/4/78-012, Environmental Research Information Center, Cincin-
nati, Ohio, October 1978. pp. 57-112. (Available from National
Technical Information Service, Springfield, Virginia, PB-299 594)
4-16
-------
CHAPTER 5
SITE EVALUATION AND SELECTION OF OPTIONS
5.1 General
This chapter is designed to assist in the identification, evaluation,
and selection of sites for the land application of sludge, and in .the
selection of a final land application option(s). At this point,
user should have reviewed the preceding chapters and have done the
lowing:
the
fol-
Estimated the present and future quantity, physical character-
istics, and chemical quality of the sludge(s) being considered
for land application.
Reviewed the pertinent federal, state, and local regulations
which apply to the project under consideration. Preferably,
this will have included a discussion with the regulatory agen-
cies involved.
Compared the data developed above, and determined that there
are no insurmountable problems with the sludge quality in terms
of its suitability for land application.
4. Recognized that the public participation process (Chapter 3) is
critical to project success, and established a public partici-
pation/education program.
1.
2.
3.
5.
Reviewed the definitions of the four land application options
covered by this manual, and the general advantages, disadvan-
tages, constraints, etc., applicable to each option (see Chap-
ter 2 and Table 2-1). Based on this knowledge, the designer
should have eliminated the land application options that are
clearly not feasible for the local situation.
Made a rough estimate of the land area required for each of the
remaining land application options (see Section 4.4 and Table
4-3).
Reviewed in a general way alternatives for sludge transport,
and recognized 'the impact of sludge transport costs upon over-
all project costs.
The careful identification, evaluation, and ultimate selection of land
application sites can prevent future environmental problems, reduce mon-
itoring requirements, minimize overall program costs, and moderate or
eliminate adverse public reaction. Poor site selection and management
practices in the past have resulted in environmental problems and public
resistance.
6.
7.
5-1
-------
5.1.1 Planning Procedure
As shown in Figure 5-1, a two-phase planning approach is suggested to
avoid; unnecessary effort and expense. The first phase involves a
screening process by review of available information and experience. If
potential sites are identified for any of the land application options
under consideration, the process moves into the second phase which in-
cludes field investigations of potential sites and detailed evaluation
of alternatives.
If more than one site and/or application option seems possible, a de-
tailed evaluation of each concept and the related costs will assist in
determining the optimum combination of site(s) and option(s).
5.2 Land Use in the Area
Prevailing or projected land use often exerts a significant influence on
site selection, as well as acceptance of a particular sludge application
option. It is necessary to determine both current and future land use
in assessing the land area potentially suitable and/or available for
sludge application. Important considerations include zoning compliance,
aesthetics, and site acquisition.
5.2.1 Current Land Use
Current land use patterns will help identify areas where land applica-
tion of sludge may or may not be acceptable. The local Soil Conserva-
tion Service (SCS) and Agricultural Extension Service representatives
have knowledge of local farming, forestry, mining, and other land use
practices. The SCS will, in many cases, have a comprehensive county
soil survey with aerial photo maps showing the land area.
5.2.1.1 Agricultural Utilization
To a great extent, prevailing farming practices dictate the acceptabil-
ity of this option. Small land holdings in a nonagricultural community
may limit the agricultural sludge application options. An area devoted
almost exclusively to production of human food crops restricts the peri-
ods when sludge can be applied to land. Areas with row crops, small
grains, hay crops, and pastures make it possible to apply sludge
throughout much of the year.
5.2.1.2 Forested Lands
A consideration in the application of sludge to forest lands is the po-
tential need to control public access for a period of time after sludge
application. Therefore, in screening current land use data, for poten-
tial sites to apply sludge to forest land, the most desirable sites are
often those owned by or leased to commercial growers, which already con-
trol public access. Publicly owned forest land has been used for sludge
application, but may require complex inter-agency negotiations and
greater public education efforts than the use of privately owned land.
5-2
-------
REVIEW LAND USE IN STUDY
AREA. IDENTIFY AGRICULTURAL
LAND, FORESTED LAND, DISTURBED
LAND AND/OR POTENTIAL DEDICATED
LAND DISPOSAL SITES. REVIEW
ZONING LAWS AND COMPLIANCE.
REVIEW PHYSICAL CHARACTERISTICS
OF POTENTIAL APPLICATION AREAS.
IDENTIFY THOSE AREAS WITH GENERALLY
SUITABLE TOPOGRAPHY, SOIL CHARAC-
TERISTICS, MINIMUM DEPTH TO GROUND
WATER, AND MINIMUM DISTANCE TO
SURFACE WATER.
I
ELIMINATE UNSUITABLE AREAS BASED ON
LAND USE AND/OR PHYSICAL CHARACTERISTICS.
1
SCREEN AND RATE REMAINING AREAS BASED
ON SUCH FACTORS AS DISTANCE FROM
POTW(S). ASSESSIBILITY VIA SUITABLE
TRANSPORT MODES, LAND OWNERSHIP AND
COST, AND PUBLIC ACCEPTANCE.
PRELIMINARY SELECTION OF POTENTIAL
SLUDGE APPLICATION SITES.
CONDUCT PRELIMINARY FIELD SURVEY OF
POTENTIAL SLUDGE1APPLICATION SITES.
VERIFY AND/OR OBTAIN ADDITIONAL
GENERAL INFORMATION PERTINENT TO
THE SITE PHYSICAL CHARACTERISTICS.
I
SELECT THOSE POTENTIAL SITES WHICH
ARE OPTIMUM AND WORTH THE EXPENSE
OF DETAILED FIELD INVESTIGATIONS.
I
CONDUCT DETAILED FIELD INVESTIGATIONS;
SOIL TESTING, GROUND WATER ANALYSIS,
EFFECTS UPON SURROUNDING LAND, AND
CROPPING PATTERNS.
I
RATE POTENTIAL OPTIMUM SLUDGE
APPLICATION SITES AND OPTIONS
AND SELECT BEST SITE IS) AND
OPTION(S).
Figure 5-1
Two-phase approach to sludge application site
identification, evaluation and selection.
5-3
-------
5.2.1.3 Drastically Disturbed Lands
Disturbed sites are relatively easy to identify in a particular local
area. The sludge application design is influenced by the potential fu-
ture use of the reclaimed land (i.e., agriculture, silvaculture, parks,
greenbelts, etc.). The application of sludge is often a one-time opera-
tion rather than a repetitive series of applications on the same site.
It is therefore necessary that (1) the mining or other operations will
continue to generate disturbed land to which sludge can be applied, or
(2) the disturbed land area is of sufficient size to allow a continuing
sludge application program over the design life of the project. State
and federal guidelines may dictate the criteria for sludge applications
and subsequent management.
5.2.1.4 Dedicated Land Disposal
Dedicated land disposal (OLD) sites usually receive much greater sludge
application rates than the other land application options, so land area
requirements are smaller. Since large quantities of sludge are being
transported, stored, and applied in a relatively small area, this option
is very sensitive to surrounding land uses, particularly housing and
commercial uses. OLD sites should generally be surrounded by areas of
limited public use.
5.2.2 Future Land Use
Projected land use plans, where they exist, may eliminate certain areas
from consideration for sludge application. Regional planners and plan-
ning commissions should be consulted to determine the projected use of
potential land application sites and adjacent properties. If the site
is located in or near a densely populated area, extensive control mea-
sures may be needed to overcome concerns and minimize potential aesthe-
tic problems which may detract from the value of adjacent properties.
Future development of potential land application sites and adjacent
properties should be considered. Master plans for the existing communi-
ties should be examined. The rate of industrial and/or municipal expan-
sion relative to prospective sites can significantly affect their long-
term suitability. For example, land dedicated for sludge disposal at
high rates might not be appropriate for either agricultural use or for
suburban home developments due to the effect of accumulated metals on
garden food crops. It is often necessary to place deed restrictions on
future use of OLD sites.
5.2.3 Zoning Compliance
Zoning and land use planning are closely related, and zoning ordinances
generally reflect future land use planning. Applicable zoning laws, if
any, which may affect potential land application sites should be re-
viewed concurrent with land use evaluations. Since it is unusual that a
community will have a specific area zoned for sludge/waste disposal,
5-4
-------
project proponents normally will have to seek a zoning change for a OLD
site. The same is true for separate sludge storage facilities.
5.2.4 Aesthetics
Selection of a land application site and/or sludge application option
can be affected by community concern over aesthetics, such as noise,
fugitive dust, and odors. In addition to application site area con-
cerns, routes for sludge transport vehicles must be carefully evaluated
in terms of avoiding residential areas, bridge load limitations, etc.
Disruption of the local scenic character and/or recreational activities,
should they occur, may generate strong local opposition to a sludge man-
agement program. Obviously, every attempt must be made to keep the ap-
plication site compatible with its surroundings and, where possible, en-
hance the beauty of the landscape. Buffer zones are often provided
around OLD sites, and are also usually required to separate sludge ap-
plication sites from residences, water supplies, surface waters, roads,
parks, playgrounds, etc.
5.2.5 Site Acquisition
Application of sludge to agricultural land can usually be accomplished
without direct purchase or lease acquisition of land. Well-prepared
educational and public participation programs early in the planning
stages normally identify numerous farmers willing to cooperate with the
city in a land application program. Experience nationwide has shown
that cooperation of this type is often less disruptive within a commun-
ity, and frequently more likely to achieve public acceptability than
land purchase.
Several different contractual arrangements between cities and landowners
for agricultural utilization have been successfully employed, including:
The city transports and spreads the sludge at no expense to
the landowner.
The city transports and spreads the sludge, and pays the land-
owner for the use of his land.
The landowner pays a nominal fee for the sludge and for the
city to transport and spread the sludge. This is most common
for agricultural utilization where there is local demand for
sludge as a fertilizer or soil conditioner.
« The city hauls the sludge and the landowner spreads it.
t The landowner hauls and spreads the sludge.
A written contract between the landowner and the sewage sludge applica-
tor is highly recommended. In some instances, the applicator will be
the municipality; in other cases, it will be a private applicator who is
transporting and spreading for the municipality.
5-5
-------
The principal advantage of a written contract is to ensure that both
parties understand the agreement prior to applying the sludge. Often,
oral contracts are entered with the best of intentions, but the land-
owner and applicator have differing notions of the rights and obliga-
tions of each party. In some cases, the contract may serve as evidence
in disputes concerning the performance of either the applicator or the
landowner. Suggested provisions of contracts between the applicator and
landowner are shown in Table 5-1 (4).
TABLE 5-1
SUGGESTED PROVISIONS OF CONTRACTS BETWEEN SLUDGE
GENERATOR, SLUDGE APPLICATOR, AND PRIVATE LANDOWNERS (4)
1. Identification of the landowner, the POTW, and the applicator spreading
the sludge.
2. Location of land where spreading is to occur and boundaries of the appli-
cation sites.
3. Entrance and exit points to application sites for use by spreading equip-
ment.
4. Specification of the range of sludge quality permitted on the land. Para-'
meters identified might include percent of total solids and levels of In,
Cu, Ni, Pb, Cd, N, P, K, and trace elements in the sludge. The contract
would specify who is to pay for the analysis and frequency of analysis.
5. Agreement on the timing of sludge application during the cropping season.
Application rates and acceptable periods of application should be identi-
fied for growing crops^ as well as periods when the soil is wet.
6. Agreements on the application rate. This rate might vary throughout the
year depending on the crop, the sludge analyses, and when and where appli-
cation is occurring.
7. Restrictions on usage of land for root crops, fresh vegetables, or live-
stock production.
8. Conditions under which either party may escape from provisions of the con-
tract.
The use of land without purchase or leasing may also find applicability
for land application of sludge to disturbed and forested lands. How-
ever, direct purchase or lease may be necessary for large city sludge
programs regardless of the land application option. In these instances,
site acquisition represents a major cost in the implementation of the
land application program.
5.3 Physical Characteristics of Potential Sites
The physical characteristics of concern are:
Topography.
Soil permeability, infiltration, and drainage patterns.
5-6
-------
Depth to ground water. .:
Proximity to surface water. .
The planner/designer should review state regulations or guidelines that
place limits on these physical characteristics of application sites.
5.3.1 Topography
Topography influences surface and subsurface water movement which af-
fects the amount of soil erosion and potential runoff of applied sludge.
Topography can indicate the kinds of soil to be found on a site.
Soils on ridge tops and steep slopes are typically well drained, well
aerated, and usually shallow. Except on very permeable soils, steep
slopes increase the possibility of surface runoff of sludge. Soils on
concave land positions an'd on broad flat lands frequently are poorly
drained, and may be waterlogged during part of the year. The soils be-
tween these two extremes will usually have intermediate properties with
respect to drainage and runoff.
The steepness, length, and shape of slopes influence the rate of runoff
from a site. Rapid surface runoff accompanied by soil erosion can erode
sludge-soil mixtures and transport them to surface waters. Therefore,
many existing state regulations/guidelines stipulate the maximum slopes
allowable for sludge application sites under various conditions, such as
sludge physical characteristics, application techniques, and application
rates. Specific guidance should be obtained from the regulatory agency;
for general guidance, suggested limits are presented in Table 5-2.
TABLE 5-2
RECOMMENDED SLOPE LIMITATIONS FOR LAND APPLICATION
OF SLUDGE (COMPILED FROM TYPICAL EXISTING STATE REGULATIONS IN 1982)
Comment
Ideal; no concern for runoff or erosion of liquid sludge or dewa-
tered sludge.
Acceptable; slight risk of erosion; surface application of liquid
sludge or dewatered sludge okay.
Injection of liquid sludge required for general cases, except in
closed drainage basin and/or extensive runoff control. Surface
application of dewatered sludge is usually acceptable.
No liquid sludge application without effective runoff control;
surface application of dewatered sludge acceptable, but Immediate
incorporation recommended.
Slopes greater than 15% are only suitable for sites with good
permeability where the slope length is short and is a minor part
of the total application area,;
30-6%
6-12%
12-15%
Over 15%
5-7
-------
5.3.2 Soil Permeability, Infiltration, and Drainage
The texture of the soil and parent geologic material is one of the most
important aspects of site selection, because it influences permeability,
infiltration, and drainage. Appendix B includes a detailed discussion
of soil characteristics relative to sludge application; it is important
that a cjualified soil scientist be involved in the assessment of soils
at potential sludge application sites.
With proper design and operation, sludge can be successfully applied to
virtually any soTT
If
ab
However, highly permeable soil (e.g., sand), highly
{e.g., clay), or poorly drained soils may present spe-
problems. Therefore, sites with such condi-
given a lower priority during the preliminary
Table 5-3 summarizes typical guidelines for
(i.e., location,
mitigation mea-
impermeable soil
cial design and operation
tions should generally be
site selection process.
soil suitability. In some cases, the favorable aspects
municipal ownership, etc.) may outweigh the costs of
sures.
5.3.2.1 Soil Permeability and Infiltration
Permeability (a property determined by soil pore space and size, shape,
and distribution) refers to the ease with which water and air are trans-
mitted through soil. Appendix B discusses these soil characteristics in
detail. Fine-textured soils generally possess slow or very slow permea-
bility, while those of coarse-textured soils range from moderately rapid
to very rapid. A medium-textured soil, such as a loam or silt loam,
tends to have moderate to slow permeability. The Soil Conservation Ser-
vice (SCS) has defined permeability classes for use in describing soils
(6), as listed in Table 5-4.
5.3.2.2 Drainage Patterns
In selecting a site for sludge utilization, a landscape consisting of or
approaching a closed drainage system may be desirable for containment of
the sludge (Figure 5-2).
The selection of a OLD site should be confined to a closed drainage sys-
tem. Whether natural or man-made, a series of protective ridges, berms,
underdrains, or other physical barriers should be provided to contain
the sludge within the site perimeter.
The U.S. SCS drainage classes are shown in Table 5-5. Very poorly
drained, poorly drained, and somewhat poorly drained classes are seldom
suitable for sludge application unless adequate surface or subsurface
tile drainage is provided (2)(5). These soils are prone to flooding and
surface ponding. Moderately well drained, well drained, and somewhat
excessively drained soils are generally suitable for waste application,
with the well drained soils offering the greatest potential for waste
renovation. Typically, a well drained soil is at least moderately per-
meable (Table 5-4).
5-8
-------
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Q.
O
as
4>
c:
cu
01
O)
J-
Q.
cu
s-
o
rd
t-
10
o
CM
I
LT>
HI
S_
ZJ
5-10
-------
TABLE 5-4
SOIL CONSERVATION SERVICE (SCS) PERMEABILITY
CLASSES FOR SATURATED SOIL (6)
Soil Permeability
(cm/hr)
<0.15
0.15 to 0.5
0.5 to' 1.5
1.5 to 5.1
5.1 to 15.2
15.2 to 51
Class
Very slow
SI ow
Moderately slow
Moderate
Moderately rapid
Rapid
-Very rapid
TABLE 5-5
SOIL CONSERVATION SERVICE (SCS) DRAINAGE CLASSES (6)
Drainage Class
Very poorly drained
Poorly drained
Somewhat poorly drained
Moderately well drained
Well drained
Somewhat excessively drained
Excessively drained
Observable Symptom
Water remains at or on the surface most of the
year.
Water remains at or near the surface much of
the year. '
Soils are wet for significant portions of the
year. -'.;.' '
.Soils are seasonally wet (e.g., high water
table in spring). ' . '-.;.:
Water readily removed from the soil either by
subsurface flow or percolation; optimum condi-
tion for plant growth.
Water is rapidly removed from the soil; char-
acteristic of many uniform sands.
Very rapid removal of water with little or no
retention.
5-11
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Excessively drained soils provide rapid water flow, and their use for
sludge application may be restricted except under the following condi-
tions:
Sludge application at very low rates. Some states will allow
sludge to be applied to any soil at very low ratess e.g., <2.2
mt/ha (1 T/ac), dry weight.
t Sludge application sites over exempted aquifers. Some ground
water aquifers are considered unacceptable for potable uses
because of poor quality, and are exempted from regulations
protecting against ground water degradation.
5.3.3 Ground Water Constraints
In preliminary screening of potential sites, it is necessary to consider
ground water information from the application area:
Depth to ground water (including historical highs and lows).
a Ground water quality and use classification by regulatory
authorities.
An estimate of ground water flow patterns.
When a specific site or sites has been selected for sludge application,
a detailed field investigation may be necessary to determine the above
information. During preliminary screening, however, published general
resources may be located at local USGS or state water resource agencies.
Generally, the greater the depth to the water table, the more desirable
a site is for sludge application. Sludge should not be placed where
there is potential for direct contact with the ground water table. The
actual thickness of unconsolidated material above a permanent water
table constitutes the effective soil depth. The desired soil depth may
vary according to sludge characteristics, soil texture, soil pH, method
of sludge application, and sludge application rate. Table 5-6 summar-
izes recommended criteria for the various sludge application options.
The kind and condition of consolidated material above the water table is
also of major importance for high-rate sludge application systems. Frac-
tured rock may allow leachate to move rapidly with little opportunity for
contaminant removal. On the other hand, unfractured bedrock at shallow
depths will restrict water movement, with the potential for ground water
mounding, subsurface lateral flow, or poor drainage. Limestone bedrock
is of particular concern where sinkholes may exist. Sinkholes, like
fractured rock, can accelerate the movement of leachate to ground water.
Potential sites with potable ground water in areas underlain by fractured
bedrock at shallow depths, or sites containing limestone sinkholes should
be avoided. Major ground water recharge zones that recharge major aqui-
fers with existing or potential use for drinking water should probably be
excluded from consideration.
5-12
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TABLE 5-6
RECOMMENDED LIMITS FOR DEPTH TO GROUND MATER
Type of Site
Agricultural
Forest
Drastically Disturbed Land
Dedicated Land Disposal
Drinking Water
Aquifer
1 m
2 int..
1 m#
At least 3 m
Excluded
Aquifer*
0.5 m
0.7.ra
0.5 m
0.5 m
* Clearances are to ensure trafficability of surface, not for ground water
protection. ' .
t Seasonal (springtime) high water and/or perched water less than 1 m is not
usually a concern (see design chapter for discussion of these limits).
# Assumes no ground water contact with Teachate from operation.
Metric Conversion: 1 m = 3.28 ft. .
5.3.4 Proximity to Surface Water
The number, size, and nature of surface water bodies'on or near a poten-
tial sludge application site are significant factors in site selection
due to potential contamination from site runoff and/or flood events. In
general, areas subject tb frequent flooding have severe limitations for
disposal of wastes. Engineered flood control structures can be con-
structed to protect a sludge application site against flooding. Because
such structures are expensive, this use is usually only applicable for a
high-rate, long-term OLD site. Table 5-7 presents typical setback dis-
tances for sludge application operations.
5.4 Site Selection Process
The selection process for sludge application sites involves the evalua-
tion of physical, chemical, economic, and social characteristics. The
information is organized to progressively eliminate unfeasible sites.
There are five steps in the procedure:
Initial site screening.
Field site survey.
t Field investigations and testing.
o Economic feasibility.
Final site selection.
5-13
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TABLE 5-7
SUGGESTED SETBACK DISTANCES FOR SLUDGE APPLICATION AREAS (16)
Distance from Feature to Sludge Application Site
15 to 90 m
,90 to 460 m1"
>460
Feature
Residential development
Inhabited dwelling
Ponds and lakes
Springs
10-year high water
mark of streams,
rivers, and creeks
Water supply wells
Public road right-
of-way
Injection' Surface Injection**
Injection
Surface and Surface
: No
Yes
Yes
No
, No
No
No
No
Yes
Yes .
'Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
No
No
Yes
Yes
Yes '
Yes
Yes
Yes
Yes
Yes
Yes
* 50 to 300 feet.
t 300 to 1,500 feet.
# >1,500 feet.
** Injection of liquid sludge or surface application of dewatered sludge.
5.4.1 Site Screening
Site screening requires:
An estimate of land area required for each utilization/dis-
posal option considered.
Elimination of unsuitable areas due to physical, environmen-
tal, social, or political reasons.
5.4.1.1 Estimate Land Area Required
Preliminary estimates of land area required for each of the alternate
sludge utilization/disposal options can be determined from data pre-
sented in Table 4-3 in Chapter 4. More precise land area requirements
are needed for design. The values from Table 4-3 should be adequate for
preliminary planning.
5.4.1.2 Eliminate Unsuitable Areas
Soil survey reports can be obtained from the local SCS offices; these
surveys are suitable for preliminary planning. When some potential
sites are identified, field inspections and investigations are necessary
5-14
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to confirm expectations. The SCS mapping units cannot represent areas
smaller than 0.8 to 1.2 ha (approximately 2 to 3 acres). Thus, there is
a possibility that small areas of soils with significantly different
characteristics may be located within a mapping unit but not identified.
Quadrangles published by the U.S. Geological Survey may be useful during
preliminary planning and screening in estimating slope, topography,
local depressions or wet areas, rock outcrops, regional drainage pat-
terns, and water table elevations. These maps are usually drawn to a
scale of 1:24,000 (7.5-minute series) or 1:62,500 (15-minute series).
Because of their scale, they too cannot be relied upon for evaluating
small parcels, and do not eliminate the need for field investigation of
candidate sludge application sites. The use of regional maps and soil
survey maps can help eliminate potentially unsuitable areas. Table 5-8
summarizes important criteria.
TABLE 5-8
POTENTIALLY UNSUITABLE AREAS FOR SLUDGE APPLICATION
1. Land adjacent to subdivisions, schools, and other inhabited dwellings.
2. Areas bordered by ponds, lakes, rivers, and streams without appropriate
buffer areas.
3. Wetlands and marshes.
4. Steep areas with sharp relief.
5. Undesirable geology (karst, fractured bedrock) (if not covered by a suf-
ficiently thick soil column).
6. Undesirable soil conditions (shallow, permafrost).
7. Areas of historical or archeologlcal significance.
8. Other environmentally sensitive areas such as floodplalris or intermittent
streams, ponds, etc. ,
9. Rocky, nonarable land.
One practical screening technique involves the use of transparent (my-
lar) overlays with concentric rings drawn around the POTW(s). The dis-
tance represented by the initial ring will vary depending on POTW loca-
tion, sludge quantity, proximity of nearby communities, local topogra-
phy, and the application option(s) being considered. A small community
might start with an area 20 km (12.5 miles) in diameter, while a large
system may initially screen a much larger study area. Shaded areas rep-
resenting unsuitable locations are marked on the map or the transpar-
ency. If the initial ring does not have suitable sites, then the next
ring with a larger diameter should be considered. It should be remem-
bered that areas which are unsuitable in their existing state can often
be modified to make them acceptable for sludge application. The neces-
sary modifications (e.g., extensive grading, drainage structures, flood
5-15
-------
control, etc.) may be cost-effective if the site is otherwise attractive
in terms of location, low land cost, etc.
5.4.2 Contact with Owners of Prospective Sites
When potential sites are identified, ownership should be determined.
Often the City Hall, County Courthouse, or a real estate broker will
have community or areawide maps indicating the tracts of land, present
owners, and property boundaries. The County Recorder and title insur-
ance companies are also useful sources of information on property owner-
ship, size of tracts, and related information. Contacting landowners
prematurely without adequate preparation may result in an initial nega-
tive reaction which is difficult to reverse. The public information
program should be prepared, and local political support secured. The
individuals involved in making the initial owner contacts should be
knowledgeable about potential program benefits and constraints (see
Chapter 3).
Initial contacts concerning the proposed project should be made with the
prospective landowners/site managers through personal interviews.Ini-
tial contacts via telephone are not recommended to avoid misunderstand-
ings regarding the benefits of any such program.
5.4.3 Field Site Survey
When the map study has identified potential sites, a field site survey
should be conducted. A drive or walk through the candidate areas should
verify or provide additional information on:
Topography - Estimate of slope both on prospective site and
adjacent plots.
Drainage - Open or closed drainage patterns.
t Distance to surface water.
Distance to water supply well(s).
Available access roads - All-weather or temporary.
Existing vegetation/cropping.
A field survey form similar to the one shown in Table 5-9 which records
the current condition of all critical factors is recommended. The data
sets collected from various sites can then be used to update the map
overlay.
5-16
-------
TABLE 5-9
SAMPLE FORM FOR PRELIMINARY FIELD SITE SURVEY
A. PROPERTY LOCATION
PROPERTY OWNER
TOPOGRAPHY
1. Relief (sharp, flat, etc.)
2. Slope Estimate
3. Drainage Patterns
- Open/Closed
- Drainage Class No.'
- Any Underdrains
DISTANCE FROM SITE BOUNDARY TO:
1. Surface Water
2. Water Supply Well
ESTIMATE OF SITE DIMENSIONS
1. Area
2.
3.
Natural Boundaries_
Fences
AVAILABLE ACCESS
1. Road Types
2. Other
EXISTING VEGETATION/CROPS AND COMMONLY USED CROP ROTATIONS
1. On-Site - '
2. Neighboring Properties
SOIL
1". Texture
2. Variability '
* Refer to Table 5-5 for drainage class.
5-17
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5.5 Field Investigation and Testing
5.5.1 General
The extent of field investigations will vary depending on:
Land application option(s) being considered, e.g., agricul-
tural, forest, land reclamation, or dedicated disposal site
(see Table 5-10).
9 Regulatory requirements.
a Completeness and suitability of soils, topographic, hydrogeo-
logic information obtained from other sources, e.g., the SCS,
USGS, etc.
Table 5-10 provides a summary of the site-specific information required*;
This information is of a general nature and can usually be obtained
without field sampling and testing. Review of this information may
eliminate some potential sites from further consideration.
5.5.2 Soil Testing
Soil test data and site characteristics normally needed when evaluating
sludge land application options are summarized in Table 5-11. Chemical
soil testing methodologies are discussed in Appendix C. Additional pro-
cedural information may be obtained from the local SCS, extension ser-
vices universities, laboratories, and consultants. Appendix B discusses
soil properties in detail.
5.5.2.1 Soil Chemical Properties
Determinations of pH, lime requirement, and cation exchange capacity
(CEC) are generally needed to assess appropriate sludge application
rates and site management practices. Soil pH and to some extent CEC in-
fluence the soil's ability to attenuate heavy metal cations (18). The
CEC is determined to a large extent by the organic matter content and
the amount and kind of clay content in soil. Generally, soils with
higher CEC values are more efficient at retaining heavy metals, and are
therefore more desirable for a sludge utilization/disposal site.
When agricultural, forestry, and reclamation utilization options are
considered, soil fertility tests are sometimes desirable in determining
the amount of supplemental fertilizer that may be needed to optimize
crop growth. These analyses, except for pH, are generally not needed
for lands dedicated for disposal. For these sites, emphasis is placed
on the soil physical properties, and engineering design is usually
geared toward pollution control, rather than agricultural productivity.
5-18
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TABLE 5-10
NECESSARY SITE-SPECIFIC INFORMATION OF A GENERAL NATURE
1. Property Ownership
2. Physical Dimensions of Site
A. Overall boundaries
B. Portion usable for sludge utilization/disposal under constraints of
topography, buffer zones, etc.
3. Current Land Use
4. Planned Future Land Use
5. If Agricultural Crops Are to Be Grown:
A. Cropping patterns
B. Typical yields
C. Methods and quantity of fertilizer application
D. Methods of soil tillage ,
E. Irrigation practices, if any
F. Final use of crop grown (animal/human consumption, non-food chain,
etc.)
G. Vehicular access within site
6. If Forest Land:
A. Age of trees
B. Species' of trees
C. Commercial or recreational operation
D. Current fertilizer application
E. Irrigation practices .
F. Vehicular access within site
7. If Drastically Disturbed Land (i.e., for reclamation option):
A. Existing vegetation
B. Historical causes of disturbance, e.g., strip mining of coal, dumping
of mine tailings, etc.
C. Previous attempts at reclamation, if any
D. Need for terrain modification
8. Surface/Ground Water Conditions
A. Location and depth of wells, if any
B. Location of surface water (occasional and permanent)
C. History of flooding and drainage problems
D. Seasonal fluctuation of ground water level
E. Quality and users of ground water
5-19
-------
TABLE 5-11
SUGGESTED SOIL TEST DATA AND SITE CHARACTERISTICS
FOR SLUDGE LAND APPLICATION OPTIONS
Field Test
Forest
DDL
OLD
Soil Chemical Property
pH
Lime Requirement
Cation Exchange Capacity (CEC)
Plant Available Nitrogen (N)*
Plant Available Phosphorus (P)
Plant Available Potassium (K)
Background Metal Analysis
Exchangeable Sodium % (ESP)a
Y
Y
Y
Y
Y
Y
Y
Ya
Y
Y
Y
-
-
-
Y
Ya
Y
Y
Y
-
-
-
Y
Ya
Y
Y
Y
-
-
-
Y
-
Soil Physical Property
t
Ground
Bedrock
Depth of Profile
Texture and Structure
Permeability
Water
Depth
Seasonal Fluctuation
Saturated Hydraulic Conductivity
Quality
Uses
Depth
Types
Fractures
Y
-b
-b
Y
-
-
-
-
_
-
""
Y
Y
Y
Y
Y
Y
Y
Y
'-
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Notes:
* Soil tests for plant available N may not be available or required for all
regions in the United States.
Y indicates that data are necessary for site selection and design.
- indicates data are not critical.
a = ESP may be critical for arid western states (see Reference 10 for discus-
sion).
b = Assumed suitable for agronomic purposes.
5-20
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5.5.2.2 Soil Physical Properties
Appendix B discusses the relationship between soil texture and struc-
ture, drainage, and stability characteristics. These physical proper-
ties are much less important if the site will be used for application of
sludge at low rates (e.g., agricultural utilization at agronomic rates),
or if dewatered or dry sludge will be applied,
5.5.3 Ground Water Testing
Field data pertinent to ground water are listed in Tables 5-10 and 5-11.
Leachate formation is of little concern for low-rate agricultural sludge
applications, and field testing and/or operational monitoring for ground
water quality may not be required.
5.6 Preliminary Cost Analysis
A preliminary estimate of relative costs should.be made as part of the
site selection process. These estimates are necessary for comparing
alternative sites and/or application options.
Proximity of the sludge application sites to the POTW(s) is very impor-
tant in the decision-making process due to high transport costs. Fur-
ther, the cost of sludge dewatering equipment may be evaluated in view
of estimated fuel savings through decreased total loads and/or shorter
haul distances. For ease of comparison, all costs should be expressed
in dollars per dry weight of sludge. Capital costs should be estimated
over the life of the site, whereas operating costs should be estimated
annually. Cost factors that are of prime importance are summarized in
Table 5-12. These assessments should be based on experience and best
engineering judgement.
TABLE 5-12
COST FACTORS TO BE CONSIDERED DURING SITE SELECTION
Capital Costs
Land acquisition - purchase, lease, or use of private land.
Site preparation - grading, roads, fences, drainage, flood control,
and buildings (if needed).
Equipment - sludge transport and application.
Sludge storage facilities.
Operating Costs
Fuel for sludge transport and application.
Labor (transport, application, maintenance, sampling, etc.).
Equipment repair.
Utilities. -
Monitoring, if required (laboratory analyses, sample containers,
shipping).
Materials and miscellaneous supplies.
5-21
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5.7 Final Site Selection
The final selection of the site(s) is often a simple decision based on
the availability of the best site(s). This is frequently the case for
small communities. If, however, the site selection process is complex,
involving many potential sites and/or several sludge utilization/dis-
posal options, a weighted scoring system may be useful.
The use of a quantitative scoring system is demonstrated in Section 4.4
of the Process Design Manual for Municipal Sludge Landfills (11). While
the criteria for selecting site(s) for the land application options dis-
cussed in this manual differ somewhat from those provided in the land-
fill design manual, the weighting and scoring system may be useful.
Several other considerations should be integrated into this decision-
making process. These include:
Compatibility, of sludge quantity and quality with the specific
land application option selected (see Chapter 4, Section 4.2,
for more detail).
Public acceptance of both the option(s) and site(s) selected.
Anticipated design life, based on assumed application rate,
land availability (capacity), projected heavy metal loading
rates, and soil properties.
5.8 Selection of Land Application Options
When the most feasible land application options have been identified,
preliminary estimates of site life expectancy and costs (capital and
O&M) for the individual options should be made. Potential social and
environmental impacts resulting from each option should also be as-
sessed. Comparison of these data should reveal the most suitable option
which fits both the needs of the POTW and local conditions. The POTW
may also consider adopting more than one land application option (e.g.,
agricultural and forested land applications) if the combined practice
appears to be cost-effective. The flow chart shown in Figure 5-3 sum-
marizes the procedure for selecting a land treatment option.
A checklist of relevant design features for each land application option
is usually helpful in compiling information, and provides baseline data
for cost estimates (see Table 5-13). Comparison and evaluation of in-
dividual options may be based on both quantitative and qualitative fac-
tors:
Estimated costs.
Potential environmental
Potential public health
Reliability.
Flexibility.
Land area requirements and availability.
impacts (adverse and beneficial).
impacts.
5-22
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CHAPTER 4t TECHNICAL ASSESSMENT
AND PRELIMINARY PLANNING
FACTORS FOR CONSIDERATION
REGULATORY REQUIREMENTS
(FEDERAL/STATE/LOCAL
PUBLIC ACCEPTANCE
SLUDGE SUITABILITY
TRANSPORT FEASIBILITY
LAND AREA REQUIREMENT
CHAPTER Si SITE EVALUATION
AND SELECTION
FACTORS FOR CONSIDERATION
LAND USE (CURRENT AND FUTURE)
ZONING COMPLIANCE
AESTHETICS
SITE ACQUISITION
SOIL CHARACTERISTICS
HYDROGEOLOGY
GO TO
APPROPRIATE
PROCESS DESIGN
CHAPTER
REVIEWING SOME OF THE FOLLOWING
CHAPTERS MAY BE NECESSARYl
- PROCESS DESIGN CHAPTERS
(CHAPTER 6 THROUGH 9)
- FACILITY DESIGN £ COST
GUIDANCE (CHAPTER 10)
- OPERATION AND MANAGEMENT
(CHAPTER 11)
FACTORS FOR CONSIDERATION!
COST EFFECTIVENESS
LONG-TERM ENVIRONMENTAL IMPACT
OTHER QUALITATIVE IMPACTS]
- IMPLEMENTABILITY
- PUBLIC HEALTH IMPACTS
- RELIABILITY
- FLEXIBILITY
- LAND-USE EFFECTS
- PUBLIC ACCEPTABILITY
- LEGISLATION
I LOOK FOR
OTHER ALTERNATIVE
1
/ IMPLEMENT THE OPTION
\ OR THE COMBINATION
Figure 5-3.
Planning, site selection, and option
selection sequence.
5-23
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TABLE 5-13
EXAMPLE DESIGN FEATURES CHECKLIST OF CANDIDATE OPTIONS
Candidate Option or Combination of Options
Subject 1. 2. 3. 4.
1. Distance and travel time from
POTO to the candidate site
2. Distance and travel time from
the storage facility to the
candidate site
3. Distance from the nearest
existing development, neigh-
bors, etc., to the candidate
site
4. Sludge modification require-
ments, e.g., dewatering
5. Mode of sludge transportation
6. Land area required
7. Site preparation/construction
needs:
a. None
b. Clearing and grading
c. Access roads (on-site and
off-site)
d. Buildings, e.g., equipment
storage
e. Fences
f. Sludge storage and transfer
facilities
g. On-site drainage control
structures
h. Off-site runoff diversion
structures
i. On-site runoff storage
j. Flood control structure
k. Ground water pollution
control structure, e.g.,
subsurface drain system
1. Soil modification require-
ments, e.g., lime addi-
tion, etc.
8. Equipment needs:
a. Sludge transport vehicle
b. Dredge
c. Pumps
d. Crawler tractor
e. Subsurface injection unit
f. Tillage tractor
g. Sludge application vehicle
h. Nurse tanks or tracks
1. Road sweeper
j. Washing trucks
k. Irrigation equipment
1. Appurtenant equipment
9. Monitoring requirements:
a. Soil
b. Vegetation
c. Surface water
d. Ground water
e. Leachate (unsaturated soil
zone)
f. Sludge analysis
10. Operational needs
a. Labor
b. Management
c. Energy
d. Repair
5-24
-------
Land use effects.
Public acceptance.
« Legislation (local, state, and federal).
5.8.1 Qualitative Impact Comparison
The qualitative comparison of each land application option is based on
the experience and judgement of the project planners and designers.
This is more difficult than a cost comparison, because the level of each
impact is more ambiguous and subject to differences of opinion. An
example of a qualitative factor comparison for a hypothetical city is
presented in Table 5-14. An example of a scoring system is presented in
Section 4.4 of the Process Design Manual for Municipal Sludge Landfills
(18). The scoring system should permit an "override" when dominating
negative or positive factors exist.
5.9 Site Selection Example
Each of the process design chapters (Chapters 6 through 9) provides a
detailed example of the design of a specific land application option.
This section provides a brief example of the site selection procedure
that could be used for a typical medium-sized community.
5.9.1 City Characteristics
Population - 34,000.
Wastewater volume - 0.18 m3/s (4 M gal/day).
Industrial wastewater contribution - approximately 10 percent.
t POTW description - conventional activated sludge, with primary
and waste activated sludge treated by anaerobic digestion.
5.9.2 Sludge Characteristics
Daily sludge generation - 2.36 dry mt/day (2.6 dry T/day).
Average solids content - 4 percent.
Average chemical properties (dry weight basis):
- Total N - 3 percent.
- NH4-N - 1 percent.
- Total P - 2 percent.
- Total K - 0.5 percent.
- Pb - 500 mg/kg.
- Zn - 2,000 mg/kg.
- Cu - 500 mg/kg.
- Ni - 100 mg/kg.
- Cd - 15 mg/kg.
5-25
-------
t_ U U >-
OJ (O QJ fO
"
1- 0) -r
Q O »-
,
"O ^ ro
01 3
:»- a. o
O CT CL4J
C. C 10 C
p ro o
c +J 4->
~
_!Oi o
_
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o,- i- ^
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-
5-26
-------
5.9.3 Regulations Considered
Assume that agricultural utilization is the only option being consid-
ered, and that special permits are not required for sludge application,
provided that:
1. Annual sludge applications do not exceed either the nitrogen
recommendations for the crop grown or the 2 kg Cd/ha (1.8 lb/
ac) limitation specified by the state agency.
2. Soil is maintained at pH 6.5 or above.
3. Annual program for routine soil testing (N, P, K) and lime re-
quirement (pH) is implemented.
4. Wastewater treatment plant measures the chemical composition of
sludge.
5. Records are maintained on the location and the amount of sludge
applied.
5.9.4 Public Acceptance
Assume that public acceptance of land application of sludge is judged to
be very good. Several nearby communities have previously established
agricultural utilization programs with excellent results. Sludge charac-
teristics from these communities were similar as were their farm manage-
ment and cropping patterns involving corn, soybeans, oats, wheat, and
pastureland.
Several articles had appeared in the local newspaper indicating that es-
calating landfill costs were causing the city to study various disposal
alternatives. No public opposition groups are known to exist.
5.9.5 Preliminary Feasibility Assessment
The above preliminary information was sufficiently encouraging to war-
rant further study of the agricultural use option.
5.9.6 Estimate Land Area Required
An application rate of 22.4 mt/ha/year (10 T/ac/year) was used as a
first approximation (see Table 4-3). The acreage required for the city
was estimated as follows:
Acreage needed -
2.36
days/yr = 3g>4
Thus, assume 40 ha (100 ac) for the preliminary search.
5-27
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5.9.7 Eliminate Unsuitable Areas
Figure 5-4 shows a general area map containing the town and surrounding
communities. Three concentric rings of 10, 20, and 30 km (6.2, 12.4,
and 18.6 mi) were drawn around the POTW. Areas directly south of the
POTW were immediately excluded because of the town boundaries. Simi-
larly, areas east and southeast were excluded because of the town's pro-
jected growth pattern, the encroachment of a neighboring city, and the
municipal airport. Further investigations to identify potential appli-
cation sites were thus concentrated to the west and northwest.
5.9.8 Identify Suitable Areas
Soil maps obtained from the local SCS office were examined within the
three radii. Areas within the 10-km (7-mi) ring were given first pri-
ority because of their proximity to the POTW. Sufficient land was lo-
cated within this distance, and the areas contained within the second
and third radii were not investigated.
Figure 5-5 is a general soil map showing one
for sludge utilization. A detailed soil map
Figure 5-6, and the map legend is presented in
potential area available
of the area is shown in
Table 5-15.
Information presented in the soil survey report included: slope, drain-
age, depth to seasonal water table, and depth to bedrock. Cation ex-
change capacities were estimated from texture, and a ranking was devel-
oped to estimate soil suitability for sludge application. The preferred
candidate sites were further examined for the characteristics listed in
Table 5-13. The rankings developed in Table 5-15 are explained in the
footnotes to the table.
Since the detailed soil map was based on an aerial photo, farm build-
ings, houses, etc., were usually identifiable. Certain portions within
this area were excluded, including:
a Areas in close proximity to houses,
ited buildings.
schools, and other inhab-
Areas immediately adjacent to ponds, lakes, rivers* and streams,
Those areas were shaded (Figure 5-6), using a mylar overlay. The re-
maining unshaded areas, covering about 930 ha (2,300 ac), were generally
pastureland with some fields of corn and oats. Within this area is
about 175 ha (432 ac) which ranks in Category 1 in Table 5-15.
The land in the site area was owned by three individuals. Since the 175
ha (432 ac) was far in excess of the 40 ha (100 ac) required, no further
sites were investigated.
5-28
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TOWN
Figure 5-4. General area map with concentric rings.
5-29
-------
KM
LEGEND
DEEP, WELL-DRAINED TO POORLY DRAINED,
MEDIUM TEXTURED AND MODERATELY FINE
TEXTURED, NEARLY LEVEL SOILS THAT
FORMED IN ALLUVIUM
DEEP, SOMEWHAT POORLY DRAINED TO WELL
DRAINED, MEDIUM-TEXTURED, NEARLY LEVEL
TO STEEP SOILS THAT FORMED IN LOESS
AND THE UNDERLYING OUTWASH, IN LOESS
AND THE UNDERLYING GLACIAL TILL OR
IN GLACIAL TILL
MODERATELY DEEP AND DEEP, WELL-DRAINED,
MEDIUM-TEXTURED, GENTLY SLOPING TO STEEP
SOILS THAT FORMED IN LOESS AND THE
UNDERLYING SANDSTONE AND SHALE RESIDUUM
Figure 5-5.
General soil map showing area selected for sludge
utilization.
5-30
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Figure 5-6.
Detailed soil survey map of potential site for
s.ludge application. Areas not suitable for use
are shaded. See Table 5-15 for ranking of
soil types.
5-31
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TABLE 5-15
RANKING OF SOIL TYPES FOR SLUDGE APPLICATION
Soil Type
AvA**
Ca**
CnB2**
CnC2
CnC3
Cn02
Cn03
Fe**
FoA**
FoB2
FoC3
Ge
Hh
La
MbA
Mb82
Md
NgA**
NgB2**
HnA
RnF
Ro**
Rp
RsB2
Sc
Sh**
Sra
Sz
We**
Wh«*
Slope
Percent
0-2
0.2
2-6
6-12
6-12
12-18
12-18
0-2
0-2
2-4
6-12
0-2
0-2
0-2
0-2
2-6
0-2
0-2
2-6
0-2
0-2
0-2
0-2
2-6
0-2
0-2
0-2
0-2
0-2
0-2
Depth to
Seasonal High
Water Table (ft)
1-3
>6
>6
>6
>6
>6
>6
3-6
>6
>6
>6
>6
1-3
>6
>6
>6
3-6
>6
>6
>6
>6
>6
>6
3-6
0-1
1-3
1-3
>6
0-1
1-3
Bedrock
(ft) Texture*
>15 sil
>15 sil
>15 sil
>15 sil
>15 sil
>15 sil
>15 sil
>15 sil
>15 1
>15 1
>15 1
>15 1
>10 sil
>15 gsal
>15 1
>15 1
>15 sicl
>15 1
>15 1
>15 1
>15 gl
>15 sicl
>15 sicl
>15 sil
>15 sicl
>15 sil
>15 1
>15 sal
>15 cl
>15 1
Drainage
Classt
P
W
W
W
W
W
W
W
W
W
W
W
SP
W
W
W
MW
W
W
W
E
W
W
MW
VP
SP
SP
W
VP
SP
Approximate
CEC
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
10-15
>5
10-15
10-15
>15
10-15
10-15
10-15
>5
>15
>15
10-15
>15
10-15
10-15
5-10
>15
10-15
Relative
Ranking^
3
1
1
2
2
3
3
2
1
1
2
1
3
1
1
1
2
1
1
1
1
1
1
2
3
3
3
1
3
3
* 1, loam; gsal, gravelly sandy loam; sil, silt, loam; sicl, silty-clay loam; cl, clay loam; sal, sandy
loam; gl, gravelly loam.
t E, excessively drained; W, well drained; MW, moderately well drained; SP, somewhat poorly drained; P,
poorly drained; VP, very poorly drained.
I 1, 0-6 percent slope, >6 ft to water table and >15 to bedrock. 2, 6-12 percent slope or 3-6 ft to water
table. 3, 12-18 percent slope or 0-3 ft to water table.
** Soil types present on potential site (see Figure 5-6).
5-32
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Soils present in the area were generally silt loams, having a CEC of
approximately 10 meq/100 g. Representative soil analysis was as fol-
1 ows:
CEC - 10 meq/100 g.
Soil pH - 6.0 (1:1 with water).
Available P - 16.8 kg/ha (15 Ib/ac).
Available K - 84 kg/ha (75 Ib/ac).
Lime necessary to raise pH to 6.5 - 5.4 t/ha (2.4 T/ac).
The three landowners were contacted individually to determine their wil-
lingness to participate. All expressed considerable interest in parti-
cipating in the program.
5.9.9 Site Survey and Field Investigation
These efforts confirmed the suitability of the site selected. Agree-
ments were thus made with each landowner to accept municipal sludge.
5.9.10 Cost Analysis
No land costs were incurred since the landowners agreed to accept the
sludge. Capital costs included: transportation vehicle, application
vehicle, sludge-loading apparatus with pumps, pipes, concrete pad, elec-
trical controls, and storage facilities. Annual costs for this option
were estimated to be $73/dry mt ($66/dry T) as compared to $85/dry mt
($77/dry T) for landfilling the sludge at a site 25 km (15.5 m) from the
POTW.
5.9.11 Final Site Selection
The 175 ha (432 ac) of best quality land were distributed over seven in-
dividual fields, several of which were not serviced by all-weather
roads. These fields would only be used if complicating factors (e.g.,
field or crop conditions) rendered the other fields unusable. The con-
tractual agreement with the three individuals specified that sludges
would be applied to certain fields (to be determined at owner discre-
tion) at rates commensurate with crop nitrogen requirements, and to pre-
vent any adverse long-term effects of heavy metal accumulations.
5.10 References
1. Gulp, G. L., J. A. Fa-isst, D. J. Hinricks, and B. R. Winsor. Evalu-
ation of Sludge Management Systems: Evaluation Checklist and Sup-
porting Commentary. EPA 430/9-80-001, Culp/Wesner/Culp, El Dorado
Hills, California, February 1980. 248 pp. (Available from Na-
tional Technical Information Service, Springfield, Virginia, PB81
108805)
2. Loehr, R. C., W. J. Jewell, J. D. Novak, W. W. Clarkson, and G. S.
Friedman. Land Application of Wastes, Vol. 1. Van Nostrand Rein-
hold, New York. 1979. 308pp.
5-33
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3. U.S. EPA. Principles and Design Criteria for Sewage Sludge Appli-
cation on Land. In: Sludge Treatment and Disposal. EPA-625/4-78-
012, Environmental Research Information Center, Cincinnati, Ohio.
October 1978. pp. 57-112. (Available from National Technical In-
formation Service, Springfield, Virginia, PB-299 594)
4. Miller, R. H., T. J. Logan, R. K. White, D..L. Foster, and J. N.
Stitzlein. Ohio Guide for Land Application of Sewage Sludge. Bul-
letin No. 598 (Revised). Cooperative Extension Service, Ohio State
University, Columbus. June 1979. 16 pp.
5. U.S. Soil Conservation Service. Guide for Interpreting Engineering
Uses of Soils. U.S. Government Printing Office, Washington, D.C.
1971. 87 pp.
6. U.S. Soil Conservation Service. Soil Survey Manual. USDA Handbook
No. 18. U.S. Government Printing Office, Washington, D.C. 1951.
503 pp.
7. Brunner, D. R., and D. J. Keller. Sanitary Landfill Design and
Operation. SW65ts. U.S. Environmental Protection Agency, Washing-
ton, D.C. 1972. 17pp. (Available from National Technical Infor-
mation Service, Springfield, Virginia, PB-227 565)
8.
9.
10.
11.
12.
13.
CHoM Hill. Initial Analysis of Candidate Systems and Preliminary
Site Identification: LA/OMA Project. Newport Beach, California.
April 1977.
Knezek, B. D., and R. H. Miller, eds. Application of Sludges and
Wastewaters on Agricultural Land: A Planning and Educational Guide.
North Central Regional Research Publication No. 235. Ohio Agricul-
tural Research and Development Center, Wooster, 1976. 88 pp.
U.S. EPA. Process Design Manual for Land Treatment of Municipal
Wastewater. EPA 625/9-81-006, October 1977. 596 pp. (Available
from National Technical Information Service, Springfield, Virginia,
PB-299 655)
U.S. EPA. Process Design Manual for Municipal Sludge Landfills.
EPA 625/1-78-010, October 1978. 331 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-299 675)
Olson, G. W. Significance of Soil Characteristics of Waste on
Land. In: Land as a Waste Management Alternative, Proceedings of
the 1976 Cornell Agricultural Waste Management Conference. Loehr,
R. C., ed. Ann Arbor Science, Ann Arbor, Michigan. 1976. pp. 79-
105.
Keeney, D.R., K.W. Lee, and L.M.
cation of Wastewater Sludge to
Technical Bulletin 88, Wisconsin
Madison, 1975. 36 pp.
Walsh. Guidelines for the Appli-
Agricultural Land in Wisconsin.
Department of Natural Resources,
5-34
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14.
15.
16.
17.
18.
Witty, J.E., and K.W. Flach. Site Selection as Related to Utili-
zation and Disposal of Organic Wastes. In: Soils for Management
of Organic Wastes and Waste Waters. Soil Science Society of Amer-
ica, Madison, Wisconsin. 1977.
Soil Conservation Service. Guide for Rating
" Waste. Interim Guide, Advisory
for Disposal
ington, D.C.,
of
1973.
Limitations of Soils
Soils, 14. Wash-
Sommers, L. E., 0. W. Nelson,
Sludge in Crop Production. AY20
tension Service. 1980.
and C. D. Spies.
Purdue University,
Use of Sewage
Cooperative Ex-
CH?M Hill. Initial Analysis of Candidate Systems and Preliminary
Site Identification: LA/OMA Project. Newport Beach, California,
April 1977.
U.S. EPA. Proceedings
Wastewater and Sludge
California, Davis, California.
July 1983).
of the Workshop on Utilization of Municipal
on Land, Denver, Colorado. University of
(In Press,
February 23-25, 1983.
5-35
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CHAPTER 6
PROCESS DESIGN FOR AGRICULTURAL UTILIZATION
6.1 General
The purpose of this chapter is to present detailed design information
for the utilization of sewage sludge on agricultural cropland. The de-
sign example presented at the end of this chapter assumes that (1) the
agricultural utilization option has been selected; (2) preliminary plan-
ning has been completed; and (3) a transportation system has been chosen
to convey sludge to the application site. Primary emphasis will be
placed on growing crops such as corn, soybeans, small grains, cotton,
sorghum, and forages.
The design approach presented in this chapter is based on the utiliza-
tion of sludge as a low-analysis replacement for commercial fertilizers.
The application rate of sludge is typically designed for either the N or
P needs of the crop grown on a particular soil. In addition, the sludge
application rate must beconsistent with existing federal, state, arid"
local regulations relative to pathogens, metals, or organics contained
in the sludge.
The U.S. EPA promulgated interim final regulations in 1979 for states to
use in limiting the total amount of Cd that can be applied to cropland
each year as well as over a period of years (10). Many states have also
developed regulations or guidelines concerning annual N and Cd limits
and cumulative Cd limits applied to agricultural cropland. If sludge is
applied to cropland at rates greater than the 1 i m i ts established for N,
increased monitoring will usually be required for potential nitrate
movement into drinking water aquifers. Exceeding the allowable limits
for Cd applications may result in restrictions on crop use (i.e., crop
use only for animal feed), and possibly restrictions on future land use.
The goal of the basic design approach presented in this chapter is to
optimize crop yields generally on privately owned land through applica-
tions of both, sludge and supplemental fertilizers, if needed. However,
other agricultural use options involving sludge application at rates in
excess of crop use rates are possible on both private and municipally
owned land. The information contained in Reference (10) will be re-
ferred to as the "Criteria" in this chapter. These regulations are
based on a management rather than a performance approach to minimizing
potential problems associated with applying sludge on cropland. The
"Criteria" (10) primarily address pathogens, Cd, and PCB's contained in
sludges. Prior to designing a specific system, pertinent current state
and local regulations must be obtained. In addition, federal regula-
tions should be examined to determine if they have been changed since
the publication of this manual.
6-1
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The design example presented at the end of this chapter assumes that
basic sludge and crop information has been collected. The sludge com-
position data required to ensure good design include:
Total solids.
Total N.
NH4-N.
NOo-N.
Total P.
Total K.
Total PCB's,
Total Pb.
Total Zn.
Total Cu.
Total Ni.
Total Cd.
Other concerns include the possibility of odors or potential exposure to
pathogens due to inadequate sludge treatment or poor site management.
The design approach described in this chapter assumes that the sludge
has been properly stabilized to reduce pathogens and odor potential.
Objections by rural residents to landspreading might be encountered if
they perceive a situation in which the urban community imposes its waste
disposal problem on the rural community. A large city is more likely to
be seen as an outsider than a small city. Rural acceptance will be more
readily forthcoming if local autonomy is assured, and if the project has
the apparent flexibility to incorporate needed changes.
The initial task for obtaining public support (see Chapter 3) begins
with the selection of a project team whose members can offer technical
service and expertise. Suggested personnel include:
Representatives of the city engineering or public works
department to direct the project and coordinate team activi-
ties.
The POTW superintendent or consultant knowledgeable in treat-
ment plant operations; preferably, a permanent sludge manage-
ment person whom the public knows as the person to contact.
Local SCS agent and agricultural extension service representa-
tives to advise on site selection, management, soil and vege-
tation evaluation, and other matters.
Local farm management firm.
Information must also be available on the types of crops to be grown,
attainable yield level, and the relationship between soil tests and fer-
tilizer application rates.
6.2 Detailed Site Investigations
An advantage of the agronomic utilization option is the minimization of
detailed site investigations. The design approach emphasizes use of
sludge as a low-analysis fertilizer with the application rates being
constrained by the N requirements or P requirements (as in Ohio) of the
crop grown and by the accumulation of metals in the surface soil. The
6-2
-------
necessary information on general site characteristics can be obtained
from a combination of soil survey maps and site visits. The principal
soil chemical analyses required are soil tests which are routinely con-
ducted to develop recommendations for application of conventional ferti-
lizer materials. Additional information on site evaluation and selec-
tion can be found in Chapter 5.
6.2.1 General Soil Properties
Following the selection of general areas, soil survey maps or equivalent
information can be used to delineate the specific locations that could
be used for sludge application. Chapter 5 describes the screening and
selection procedures to be used.
6.2.1.1 Physical Features
Several states have established guidelines or regulations for minimum
distances between an area receiving sludge and adjacent site features
such as residential developments, inhabitated dwellings, ponds and
lakes, springs, 10-year high water mark of streams, rivers and creeks,
water supply wells, and public road rights-of-way. The potential for
surface runoff of liquid sludge is the primary reason for these guide-
lines. If liquid sludge is immediately incorporated into the soil
rather than allowed to remain on the soil surface, it can then be ap-
plied at a closer distance. Since the potential for runoff is signifi-
cantly less for dewatered sludge than for liquid sludge, the setback
distances for dewatered sludge applied to the soil surface are generally
the same as those for liquid sludge incorporated into the soil. In ad-
dition, very low sludge application rates, e.g., less than 2-4 mt/ha (1-
2 T/ac), reduce the risks of runoff, and may allow reduction of setback
distances. General guidelines for setback distances from sites treated
with liquid and dewatered sludges by surface or incorporated applica-
tions are presented in Chapter 5, Table 5-7. Local and/or state regula-
tions must be consulted when designing a specific project, since the
criteria in Table 5-7 may not be as stringent as particular local lim-
its.
6.2.1.2 Topography
The sludge application rates employed in an agricultural utilization
program typically range from 5 to 20 mt/ha (2.2 to 9 T/ac) on a dry
weight basis. For liquid sludge at 5 percent solids, these rates cor-
respond to 100 to 400 nr/ha (0.4 to 1.5 acre-in). The volumes of liquid
sludge applied are therefore far less than the natural annual rainfall
in nearly all regions of the United States. Since these volumes are not
excessive, use of appropriate sludge application techniques and runoff
control measures for different soil slopes will minimize the potential
for contamination of surface waters. General slope criteria are pre-
sented in, Chapter 5, Table 5-2, for preliminary site selection pur-
poses.
6-3
-------
The measures used to control surface runoff from soils treated with
sludge are the same as those designed to prevent soil erosion. These
practices include strip cropping, terraces, grassed waterways, and re-
duced tillage systems (e.g., chisel plowing, no-till planting). The
presence of vegetation and/or crop residues on the soil surface is ef-
fective in reducing runoff from steeply sloping soils. For many crop-
ping systems (e.g., corn, soybeans, small grains), liquid sludge applied
to the surface is incorporated into the soil by plowing or disking prior
to crop planting, further reducing the potential for loss of sludge con-
stituents via surface runoff. In essence, selection of the proper
sludge application method (surfaceTr incorporation) in conjunction with
rpj
il
currently recommended practices for control of soil erosion will essen-
tially eliminate the potential contamination of surface waters or adja-
cent lands by sludge constituents. '' ;
6.2.1.3 Depth to Ground Water
The ideal sludge application site would contain a deep and well-devel-
oped soil to protect the integrity of ground water resources. A basic
philosophy inherent in federal and many state regulations is to design
sludge application systems that are based on sound agronomic principles.
"" that sludge utilization poses no greater threat to ground water re-
so
f "_T._ _. «-^ >" v »» ^V^N^^J 11 v vji___**** \f\~i i* i ii GH \f \,\j y | L/UIIU WuUCI 1C""
sources than current agricultural practices.Because the ground water
fluctuates on a seasonal basis in many soils, difficulties are encoun-
tered in establishing an acceptable minimum depth to ground water for
sludge application sites. Usually, the greater the depth of soil above
ground water, the less potential for sludge constituents (primarily N0o~)
to migrate into water supplies. Local or state regulations often specify
that the minimum distance to ground water should be 1 m (3 ft). However,
this type of regulation is often difficult to interpret in practice, be-
cause many productive agricultural soils have naturally occurring sea-
sonal water tables within 1 m (3 ft) of the surface. These soils can be
ideal sites for sludge application, because tile drains have been in-
stalled to improve subsurface drainage, and because the soils have the
fertility to support excellent crop yields. The perched water table be-
neath these soils is normally not used as a water supply. (See Table 5-6
for general guidance on depth to ground water.)
The primary sludge constituent that can leach into ground water is ni-
trate nitrogen. Following application of sludge, nitrate is formed by
nitrification of the ammonium either added in the sludge or released
during decomposition of sludge organic N. Nitrate is a water-soluble
anion that will move downward readily in the soil profile. Nitrate
leaching will occur if excessive amounts of N are supplied to soils in
the form of fertilizers, animal wastes,
Nitrate leaching is minimized by applying
sistent with the N required by the crop
metals, phosphorus, and organics
sludges, or other materials.
sludge at a rate and time con-
grown. Downward movement of
usually
metais. pnospnorus, and organics are usually not encountered, because
these sludge constituents are relatively immobile in soils.Essentially
of the applied metals, pathogens, phosphorus, and organics remain,in
upper 15 to 30 cm (5 to 10 in) of soil (i.e., depth of tillage).
ai I
the
6-4
-------
The movement of metals is further reduced by maintaining the soil at pH
6.5 or above, as currently required to minimize plant uptake of metals.
6.2.2 Soil Sampling and Analysis
A soil sampling and analysis program is needed to establish limits for
cumulative metal applications, to determine the amounts of supplemental
fertilizer needed, and to evaluate soil pH. These data, in conjunction
with crop and sludge data, will allow calculations of annual sludge ap-
plication rates and site life. It is recommended that soil samples be
collected from each field that will be treated with sludge. If a given
field exceeds 10 ha (25 ac), individual soil samples should be collected
from each soil series within the field. Valid soil sampling procedures
are essential. Information can be obtained from university or private
soil testing laboratories on proper procedures for obtaining and han-
dling soil samples (also see Appendix C). The required soil analysis
determines (1) plant available P and K; (2) soil pH and lime require-
ment; and (3) CEC. Sampling and analytical methods ,are presented in
Appendix C. These tests, except for CEC, are routinely performed for
most farmers every 2 to 4 years.
In many regions of the United States, a specific soil test is not used
to develop N fertilizer needs. Some midwestern states relate N fertili-
zer applications to soil organic matter, while the nitrate contained in
the soil profile is considered in some western states where crops are
grown under irrigation. Information presented in this chapter assumes
that N application rates are based on the N required by a crop at a spe-
cific yield level.
6.2.2.1 Plant Available Phosphorus and Potassium
The amount of plant available P is determined by analyzing the amount of
P removed from soil by a particular extractant. The extractant used
varies in different regions of the United States, but is typically a
dilute acid or a bicarbonate solution. Essentially, all P taken up by
crops is present in insoluble forms in soils rather than being in the
soil solution. In all states, it has been determined that there is a
relationship between the amount of extractable P in a soil and the
amount of P fertilizer needed for various yields of different crops.
Such information can be obtained from extension services, universities,
etc.
As with P, an extractant is used to determine the plant available K in a
soil. Potassium available for plant uptake is present in the soil solu-
tion, and is also retained as an exchangeable cation on the cation ex-
change complex of the soil. The amount of plant available K is then
used to determine the K fertilizer rate for the crop grown. Sludges are
usually deficient in K, relative to crop needs.
6-5
-------
These test data are then used to calculate whether supplemental P or K
fertilizer is needed to optimize crop yields following sludge applica-
tion. Assistance on interpreting soil test data and fertilizer recom-
mendations can be obtained from local extension agents, farm management
and consultant firms, and fertilizer dealers.
6.2.2.2 Soil pH and Lime Requirement
Most states require that soils treated with sludge be maintained at pH
6.5 or above to minimize the uptake of metals by crops. Soil pH is rou-
tinely determined by soil testing laboratories. If soil pH is less than
6.5, a laboratory test procedure is used to estimate the amount of agri-
cultural limestone required to adjust the soil to pH 6.5.
Soil pH control has been practiced routinely in those areas of the Uni-
ted States where leguminous crops (e.g., clover, alfalfa, peas, beans)
are grown. Fortunately, limestone deposits' are normally abundant in
these regions, resulting in minimal costs associated with liming soils
to pH 6.5. However, considerable cost may be associated with liming
soils to pH 6.5 in other areas of the United States (e.g., eastern and
southeastern states). Soils in these regions tend to be naturally acid,
and may require relatively large amounts of limestone (12 to 20 mt/ha;
5 to 8 T/ac) to attain pH 6.5. Furthermore, the general trend toward
increased growth of cash grain crops (corn, small grains) has caused
soil pH to decrease because of greater N fertilizer use. Excellent
yields of corn, soybeans, and wheat can be obtained at a soil pH of 5.5
to 6.0. Most soils in the western United States contain free calcium
carbonate, and naturally possess a pH >6.5.
Soil pH is buffered by inorganic and organic colloids. Thus, it does
not increase immediately after limestone applications, nor does it de-
crease soon after sludge or N fertilizer additions. It is strongly rec-
ommended that soil pH be maintained at 6.5 or above after sludge appli-
cations cease to minimize plant uptake of metals. All calcareous soils
naturally meet this recommendation.
6.2.2.3 Cation Exchange Capacity
Many states have established limitations on the total (cumulative)
amounts of Pb, Zn, Cu, Ni, and Cd that can be applied to cropland.
These limits then control the total amount of sludge that can be applied
over a period of years (see Section 6.3.5). Soil CEC is employed to re-
late total metal additions to the ability of a soil to minimize metal
uptake by plants. The CEC of a soil is a measure of the net negative
charge associated with both clay minerals and organic matter. The CEC
determination is a routine analysis in many soil testing laboratories,
and will be done upon request in nearly all other laboratories.
6-6
-------
6.3 Constraints
The constraints associated with application of sludge on agricultural
cropland are dependent on the type of crop grown, soil characteristics:,
and specific sludge constituents, including pathogens, organics, N, Pb9
Zn, Cu, Ni, and Cd. Since state regulations vary in different regions
of the United States,'the following discussion emphasizes the general
constraints placed on the application of sludge on cropland by the "Cri-
teria" (10).
6.3.1 Pathogens !
Untreated raw sludges contain a variety of potential pathogens, includ-
ing bacteria, protozoa, helminthic parasites, and viruses. Additional
information on the pathogen content of sludges and their fate in soils
is contained in Appendix A. Sludge treatment processes can be used to
significantly reduce the pathogen content of sludges. Typical stabili-
zation processes include aerobic digestion, anaerobic digestion, long-
term storage in a lagoon, extended air-drying on drying beds, compost-
ing, and lime (CaO) treatment. The "Criteria" (10) refer to these pro-
cesses as ones that "significantly reduce pathogens." All sludges ap-
plied to agricultural cropland must be treated by such a process, if a
crop that enters the human diet, either directly or indirectly, is
grown. An example of direct entry into the human diet would be bread
derived from wheat grown in sludge-treated soils. Corn or forage fed to
livestock would constitute a route for indirect entry. The "Criteria"
(10) also contain other stipulations on sludge application to cropland:
(1) site access must be controlled for 12 months after application; (2)
no animals should be grazed on the site for 1 month after application if
the animal product will be consumed by humans; and (3) crops consumed
raw (e.g., root crops and vegetables) by humans cannot be grown for 18
months after the time of sludge application, unless there is no contact
between crop and sludge (e.g., peas or corn which are not typically con-
sumed raw). '
The "Criteria" (10) also define conditions for sludge treatment pro-
cesses that "further reduce pathogen content of sludge." Examples of
these processes would be high-temperature aerobic or anaerobic diges-
tion, irradiation, and heat drying. If one of these processes is used
to further reduce the pathogen content of sludge, crops consumed raw can
be grown within 18 months after application. The pertinent federal reg-
ulations, along with state or local rules, must be consulted to design a
specific system.
There have not been any serious disease problems reported .from the ap-
plication of stabilized sludges on agricultural cropland. Numerous con-
cerns are always voiced by the public whenever sludge utilization proj-
ects are discussed at public hearings. The emotional arguments pre-
sented are always difficult to counteract, because the imagined problems
and aesthetic considerations (i.e., growing food for human consumption
on soils treated with human wastes) are not negated by merely presenting
6-7
-------
facts. In general, the public wants a guarantee that not a single virus
or bacteria will ever enter their food or water supply. Such a guaran-
tee cannot be made for any type of wastewater treatment or sludge man-
agement program.
6.3.2 Nitrogen
Nitrogen is the nutrient that is required in the largest amounts by all
crops. The addition of N to soils in excess of crop needs results in
the potential for N03~ contamination of ground water. Nitrate is not
adsorbed by soil particles, and will readily move downward as water per-
colates through the soil profile. The ammonium-N either initially pre-
sent or released from organic N will be rapidly converted to N03~ fol-
lowing addition of sludge to soil. A similar problem results from ex-
cessive applications of animal wastes and conventional nitrogen fertili-
zer materials.
High NOo" levels in water supplies may result in health problems for
both infants and livestock. The maximum allowable concentration of N03~
in potable drinking water has been established at 10 mg N03~N/1 (45.mg
N03/l). The amount of plant available N applied to soils in sewage
sludge should be consistent with the current N fertilizer recommenda-
tions for the crop grown. As a result, the threat of N03 contamination
of ground water at a well managed sludge utilization site should be no
greater than that caused by the use of conventional N fertilizers. This
approach places a constraint on the amount of sludge applied to soil
each year, because N requirements of different crops can range from 50
kg N/ha (45 Ib N/ac) to over 350 kg N/ha (312 Ib N/ac).
6.3.3 Organics
Most sludges contain organic compounds, primarily chlorinated hydrocar-
bons, which are relatively resistant to decomposition in soils and may
be of concern from a human health standpoint. PCB's are the only group
of organic compounds addressed in the "Criteria" (10).
These federal regulations require that all sludges containing greater
than 10 mg PCB/kg must be incorporated into the soil whenever animal
feed crops are grown. The
direct ingestion by animals
applied sludge. Dairy cattle
principal problem arising from PCB's is
grazing on forages treated with surface-
are most susceptible to PCB contamination
of forages, because PCB's in the diet are readily partitioned into milk
fat. Several studies have shown that essentially no plant uptake of
although PCB's can be adsorbed onto the surface of root
carrots.
PCB's
crops
occurs,
such as
The majority of sludges in the United
States
limit
contain
the
less than 10 mg
PCB/kg; therefore, PCB restrictions will limit the use of only a small
percentage of sludges.Since PCB's are no longer manufactured, PCB-
related constraints should become less common in the future. Other
organic compounds detected in sludges are summarized in Appendix A.
6-8
-------
6.3.4 Cadmium
From a human health standpoint, Cd is the sludge-borne metal that has
received the greatest attention. It has been estimated that the current
dietary intake of Cd by the U.S. population is less than 50 percent of
the limit set by the World Health Organization, and that increased Cd
levels are sometimes observed following application of sludges to soils.
Cd contained in the diet, whether derived from soil or sludge sources,
accumulates in the kidneys, and may cause a chronic disease called pro-
teinuria (increased excretion of protein in the urine).
It is difficult to predict the effect of sludge application on Cd in the
human diet for the following reasons:
Crops vary markedly in Cd uptake (e.g., leafy vegetables are
significantly higher in Cd than cereal crops).
Cd uptake by crops is dependent on soil properties and the
amount of Cd applied.
The Cd content of the current human diet is not accurately
known, and varies with each individual's diet preferences.
e Projected increases in dietary Cd due to sludge utilization
are strongly influenced by the proportion of land treated with
sludge, the types of crops grown, soil properties, and other
factors.
The reader is referred to
Cd by crops (14) and the
(15). Table 6-1 summarizes
crops.
recent publications discussing the uptake of
impact of sludge application on dietary Cd
relative accumulation of Cd in common food
The "Criteria" (10) specify interim final limits for annual and cumula-
tive amounts of Cd applied to different crops, and require that soil pH
be maintained at 6.5 or above. These regulations were developed from
considerations of allowable increases in dietary Cd for a worst case
situation, e.g., a vegetarian growing 100 percent of his food on an
acid, sludge-treated soil. Even though application of most sludges will
increase the Cd content of some crops, the regulations were designed to
limit the increases to a level where no adverse effect on human health
would result. The crop Cd concentrations of concern to human health are
far below those where Cd decreases crop yields (i.e., phytotoxicity from
Cd), so phytotoxicity does not offer protection against excessive levels
of Cd in crops. Some states have adopted more conservative limitations
on total Cd applications to cropland, so it is imperative to consult
state regulations when,designing, a specific system.
6-9
-------
6.3.5 Lead, Zinc, Copper, and Nickel
In addition to Cd, the cumulative amounts of Pb, Zn,< Cu, and Ni applied
to soils in sludge can be used to determine the number of years that
sludge can be utilized. The recommendations in Table 6-2 for Pb, Zn,
Cu, and Ni were developed through the joint efforts of researchers in
various Agricultural Experiment Stations, U. S. -Department of Agricul-
ture, and EPA, and were adopted as guidelines by EPA in 1977 (6). Some
states have developed regulations which are very similar.
Limitations on total metal additions to soils are needed to protect soil
productivity and animal health. The majority of crops do not accumulate
Pb, but there is concern regarding the potential ingestion of Pb and
possibly other trace elements (Cu, Se, Mo) by animals grazing on sludge-
contaminated forages and indirect consumption of soil. The surface ap-
plication of sludge on forages can lead to some sludge adhering to the
foliage, resulting in direct consumption by grazing animals. Further-
more, raindrop splash can cause contamination of foliage with soil-
sludge materials, and animals typically consume some soil when grazing.
The total amounts of Zn, Cu, and Ni applied are limited, because crop
yields will decrease (phytotoxicity) if excessive amounts of these met-
als are added to soils. In general, Zn, Cu, and Ni will be toxic to
crops before their concentration in plant tissues reaches a level that
poses a problem to human or animal health.The cumulative metal limits
(Table 6-2} assume that soil pH is maintained at 6.5 or above during and
after sludge application.
These cumulative metal limits are a function of soil CEC. The use of
soil CEC in establishing metal limits does not imply that metals added
to soils in sludge are retained by the exchange complex as an exchange-
able cation. It has been shown experimentally that nearly all metals in
sludge-amended soils are not present -as an exchangeable cation (i.e.,
exchangeable with a neutral salt). Thus, CEC was chosen as an indicator
of soil properties, since it is easily measured and related to soil com-
ponents that minimize plant availability of sludge-borne metals in soil.
In general, the CEC categories of <5, 5-15, and >15 meq/100 g correspond
to sands, sandy loams, and silt loams, respectively; however, regional
differences in this relationship occur.
Sludge applications should cease when any single metal limit is attained
(see Table 6-2). If soil pH is maintained at 6.5 or above, cessation of
sludge application at the limits presented should enable the growth of
any crop in the future without adverse affects on yield. In addition,
soil productivity will be at a level equal to, and most likely greater
than, that which existed prior to initiation of sludge application.
6.3.6 Other Sludge Constituents
The yields of agronomic crops can be influenced by other sludge consti-
tuents in certain regions of the United States. For example, in arid
regions where most crops are irrigated, soluble salts, Mo, and B should
6-10
-------
TABLE 6-1
RELATIVE ACCUMULATION OF CADMIUM INTO
EDIBLE PLANT PARTS BY DIFFERENT CROPS (7)*
High Uptake
Lettuce
Spinach
Chard
Escarole
Endive
Cress
Turnip greens
Beet greens
Carrot
Moderate Uptake
Kale
Col lards
Beet
Turnip root
Raddish globes
Mustard
Potato
Onion
Low Uptake
Cabbage
Sweet corn
Broccoli
Cauliflower
Brtissel sprouts
Cel ery
Berry fruits
Very Low Uptake
Snapbean family
Pea
Melon family
Tomato
Pepper
Eggplant
Tree fruits
* The above classification is based upon the response of crops grown on
acidic soils that have received a cumulative Cd application of 5 kg/ha.
It should not be implied that the above higher uptake crops cannot be
grown on such a soil, or soils of higher Cd concentrations. Such crops
can be safely grown if the soil pH is 6.5 or greater at the time of
planting, since the tendency of the crop to accumulate heavy metals is
significantly reduced as the soil pH increases above 6.5.
TABLE 6-2
RECOMMENDED CUMULATIVE LIMITS FOR METALS OF
MAJOR CONCERN APPLIED -TO AGRICULTURAL CROPLAND (6) (9)'
Soil Cation Exchange Capacity, meg/100
<5
5 to 15
Pb
Zn
Cu
Ni
Cd
560 (500)
280 (250)
140 (125)
140 (125)
5 (4.4)
--&y/na iiu/ai.;
1,120 (1,000)
560 (500)
280 (250)
280 (250)
10 (8.9)
2,240 (2,000)
1,120 (1,000)
560 (500)
560 (500)
20 (17.8)
* See Table 4-2 in Chapter 4 for guidance on use of sludge for
production of fruits and vegetables.
t Interpolation should be used to obtain values in the CEC range
5-15.
# Soil must be maintained at pH 6.5 or above.
** Ib/ac shown in parentheses.
6-11
-------
be considered when determining sludge application rates. The concentra-
tion of these components in the irrigation water, along with the amount
applied in sludge, should be considered to minimize any potential prob-
lems. Information on the quality of local irrigation water and the pre-
vailing irrigation management systems must be obtained to design sludge
utilization systems in irrigated regions (16). In nonirrigated areas,
soluble salts are rarely a problem because of minimal soluble salts in
sludge and low application rates.
Sludges may also contain other trace elements such as Hg, Cr, As, and
Se. These elements are not included in the design criteria either be-
cause of the minimal uptake by crops (4)(6)(8) or the relatively low
concentrations in most sludges. The range and median concentrations for
elements commonly found in sludge are shown in Appendix A. Abnormally
high levels of specific chemical species should be dealt with on a case-
by-case basis. Pretreatment of industrial waste streams prior to dis-
charge into the sewerage system may be necessary prior to utilization of
sludge on cropland. Further, sludges that are grossly contaminated with
metals or organics will not likely pass the U.S. EPA extraction proce-
dure for toxic and hazardous waste (17), and must thus be disposed of at
an approved hazardous waste disposal site.
6.4 Sludge Application Rate Calculations
Sludge application rates are calculated from data on sludge composition,
soil test information, N fertilizer need of the crop grown, and limits
on annual Cd additions. In essence, this approach views sludge as a
substitute for conventional N fertilizers in crop production. The num-
ber of years that sludge can be applied is based on recommended limits
for total additions of Pb, Zn, Cu, Ni, and Cd, as shown in Table 6-2.
Since the majority of sludges contain roughly equal amounts of total N
and P while crops requirements for N are two to five times greater than
those for P, a conservative approach to annual sludge application rates
involves applying sludge to meet the P rather than N needs of the crop.
Sludges could also be applied to agricultural cropland at rates that ex-
ceed the N requirements of crop or the prevailing limitations on Cd
additions. These types of systems should be viewed as dedicated sludge
disposal sites that require more intensive monitoring, careful control
of the end use of any crop grown, and possible restrictions on future
site use (see Chapter 9).
The general approach for determining
cropland can be summarized as follows:
application rates on agricultural
Nutrient requirements for the crop selected are based on the
yield level and soil test data. If sludge has been applied in
previous years, fertilizer recommendations are corrected for
carry-over of nutrients added by previous sludge additions.
6-12
-------
o Annual sludge application rates are calculated based on N crop
needs, Cd limitation, P crop needs, and fixed rate (may exceed
N needed by crop or Cd limit).
Supplemental fertilizer is determined from N, P, and K needed
by crop and amount applied in sludge.
Sludge applications are terminated when a cumulative metal
limit is reached.
6.4.1 Crop Selection and Nutrient Requirements
It is usually advantageous to maintain or utilize the normal cropping
patterns found in the community. These patterns have evolved because of
local soil, climatic, and economic conditions, and will probably main-
tain certain advantages in the sludge application system as well. One
possible exception could occur if the cropping pattern was restricted to
a single crop. In this case, additional crops could increase the oppor-
tunity of applying sludge during a variety of seasons.
The crops grown in an area will influence the scheduling and methods of
sludge application. Since sludge applications are typically limited by
the N required by the crop, forages, corn, and soybeans will minimize
the amount of land needed and the costs associated with sludge transpor-
tation and application. However, corn and soybeans actively grow from
approximately May to October or November, limiting sludge applications
to only a few months of the year. Forage crops, legumes, and grasses
are capable of utilizing large amounts of sludge-derived nutrients, but
only surface applications are practical on forages that are mowed and
baled for animal feed. Injection of sludge into permanent pastures
might be acceptable if the farmer is willing to tolerate the negative
effects on trafficability. In general, the constraints discussed in
previous sections will combine to favor the use of sludge on a mixture
of crops such as small grains, cereals, and forages.
Fertilizer recommendations for crops are based on the nutrients needed
for the desired yield at a specific level of plant available nutrients
in the soil. The amounts of fertilizer N, P, and K required to attain a
given crop yield have been determined experimentally for numerous soils
in each region of the United States. The crop response has been related
to the fertilizer added and the soil test levels for P, K, and trace
elements (Zn, Cu, Fe, Mn). As discussed in Section 6.2.1, reliable
methods are not available for estimating the plant available N content
in most soils. As a result, fertilizer N recommendations are controlled
primarily by past experiences with crop yields, and secondarily by the
carryover of N from the previous crop grown. This latter point is
illustrated by the greater plant available N levels' in soil if corn is
grown after alfalfa (a legume which fixes atmospheric N2) versus corn
grown after corn (where no N2 fixation occurs).
6-13
-------
For all crops, yield potential and soil fertility are controlled by such
factors as the amount and distribution of rainfall, soil physical prop-
erties (drainage, crusting, water-holding capacity, and compaction),
length of growing season, available heat units, and incidence of weed,
insect, and disease problems. All of these factors are integrated into
the yield level observed for each crop. For example, two silt loam
soils located in a specific county may have identical soil fertility and
management levels, but different yield potentials. While one soil his-
torically produces corn at only 247 bu/ha (100 bu/ac), the other soil
may be capable of producing 445 bu/ha (180 bu/ac). To design a sludge
utilization project, it is essential to obtain local yield information
on the potential of crops grown on the specific soil types to be used.
As an illustration of the general approach used, typical midwest rela-
tionships between yield level, soil test levels for plant available P
and K, and P and K fertilizer requirements are shown in Tables 6-3
through 6-6 for various crops. The amount of supplemental P and K
needed by crops increases as the yield level increases for a fixed range
of existing plant available P and K in the soil. Conversely, fertilizer
needs decrease at a specific yield level as plant available P and K in-
crease. The amounts of N required for each yield level are also shown
in Tables 6-3 to 6-6. The data presented in Table 6-7 can be used to
correct the N requirements of crops for the amount of plant available N
remaining from previous sludge applications. The crop nutrient require-
ments presented are step functions between yield and fertilizer addi-
tions, whereas nutrient uptake is a continuous function of plant avail-
able nutrients. Some states recommend fertilizer application rates for
a specific yield, rather than a range of yields.
Information on fertilizer recommendations for a specific project can be
obtained from the Agricultural Experiment Stations in each state, or
from local extension personnel.
6.4.2 Calculation of Residual N, P, and K
When sludges are applied to soils each year, the N, P, or K added in
previous years which are not taken up by crops can be partially avail-
able during the current cropping season. For example, sludges applied
at a rate to meet the N needs of a crop will typically result in in-
creased soil P levels. This same situation could also exist for K with
the application of sludge containing high K levels.
The contribution of residual N to plant available N can be significant
when sludges are applied each year. Although the largest percentage of
mineralizable organic N is converted to inorganic N during the year that
the sludge is applied, the continued decomposition of organic N in suc-
ceeding years can provide a significant portion of the N needed for crop
growth. The amount of N mineralized in sludge-treated soils is depend-
ent on the type of sludge treatment processes used, the ratio of inor-
ganic to organic N in the sludge, and the amount of organic N applied in
previous years. A detailed discussion of the N cycle is presented in
Appendix B.
6-14
-------
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6-19
-------
The approach proposed for evaluating residual N, P, and K is as follows:
P and K - Assume that 50 percent of the
for plant uptake. If P in excess of
applied in previous years,
grown in the current year
test data are
should be used
quirements.
P applied is available
plant needs has been
it can be utilized by the crop
If post-sludge application soil
available for P and K, these measured values
to assess supplemental P and K fertilizer re-
N - The portion of organic N converted to inorganic N varies
for different sludge types during the first year after appli-
cation to the soil. After the first year, the amount of N
mineralization decreases by approximately 50 percent each year
until the N mineralization stabilizes at about 3 percent of
the remaining organic N. For example, if 20 percent of the
organic N was mineralized during the first year, the amounts
released in years 2, 3, 4, and 5 would be 10, 5, 3, and 3 per-
of the organic N remaining (see Table 6-
N mineralization rate of 3 percent was
is often observed for stable organic N
cent, respectively,
7). The ultimate
chosen, because it
fractions in soils.
6.4.3 Calculation of Annual Application Rate
Recommended annual rates of sludge application on cropland are based on
the N, P, and Cd content of the sludge and the N and P requirement of
the crop grown. As discussed in the previous section, the N needs of
the crop are corrected for plant available N mineralized from prior
sludge additions. There are three basic approaches that can be used to
determine the annual application rate:
Approach 1 - Annual rate applies N
and Cd less than regulatory limits.
equivalent to crop N need
Approach 2 - Annual rate applies Cd equal to regulatory limit
and N less than crop N need.
Approach 3 - Annual rate applies P equal to crop P need (N
applied < crop N need and Cd applied < current regulatory
limit).
For all three approaches, the soil pH must be maintained at
greater to minimize metal uptake by crops.
6.5 or
The following section summarizes the basic calculations used to deter-
mine sludge application rates. The basic calculations required are sim-
ilar for all three approaches. The design examples at the end of this
chapter illustrate calculations for each approach.
6-20
-------
6.4.3.1 Calculation of Nitrogen Applied
The plant available N content in
organic N, NHA+-N, and NOo-N analyses.
sludge is determined from the total or
It is assumed that both NH/i+ and
4
N0o~ present in soil after sludge application are available for 'plant
uptake during the cropping season of sludge application. This assump-
tion is consistent with the current practices of applying anhydrous am-
monia, ammonium nitrate, ammonium sulfate, potassium nitrate, or urea as
nitrogen fertilizers. In contrast to conventional fertilizer materials,
however, appreciable amounts of organic N are added to soils in sludges.
Mineralization of the organic N provides a slow release of plant avail-
able N during the growing season and in future years.
As shown in Table 6-7, the percent of organic N mineralized is generally
related to the sludge characteristics resulting from a particular treat-
ment process (11). In general, the greater the degree of sludge pro-
cessing within the sewage treatment plant, the lower the amounts of
organic N released for plant uptake after application to soils. The N
mineralization percentages shown in Table 6-7 can be employed to calcu-
late the plant available N content of a sludge, and to correct the fer-
tilizer N recommendation for previous sludge applications. However,
there is a significant variation in conversion rates of organic N to in-
organic N in sludge receiving similar treatment. The mineralization
rates shown on Table 6-7 are averages only. It is recommended that in-
cubation studies be done on specific sludges to determine exact mineral-
ization rates.
The amount of plant available sludge-borne N applied to soil is also de-
pendent on the application method used. Recent research has shown that
approximately 50 percent of the NH4+ is lost to the atmosphere through
volatilization of NH-D when liquid sludges are applied to the soil sur-
face and allowed to dry before being incorporated (see Appendix B). As
a result, only 50 percent of the NH^+ applied is assumed to be available
for plant uptake. For all sludges, the plant available N content (ND)
is determined using the procedures defined below (calculations are per-
formed on a dry weight basis).
The N in a particular year is the total of:
All of the nitrate (NOg) present in the sludge.
All or a fraction of the ammonia (NH4) present in the sludge.
If the sludge is liquid and surface-applied, assume that only
50 percent of the NH4 is plant available, with the remaining
50 percent lost through volatilization during application.
However, if the sludge is liquid and incorporated (injected),
or dewatered sludge applied in any manner, assume that 100
percent of the NH^ is plant available.
A fraction of the organic N (NQ) present in the sludge which
is mineralized during the first year after application. This
6-21
-------
fraction is represented by the column headed "F" in Table 6-7
for the year 0-1.
A summation of the NQ in the sludge applied during previous
years (if any) which will mineralize during the particular
year being calculated. This fraction is represented by the
column headed "F" in Table 6-7 for the year(s) since the ear-
lier sludge application.
A two-step calculation is recommended to determine Np in a particular
year.
Step 1, represented by Equation 6-1 below, accounts for the N available
from the sludge during the first year in which it is applied^
Np = S [(N03) + Kv (NH4) + F(yeap 0_1} (NQ)] (10) (6-1)
where:
Np =Plant available N from this year's sludge application only,
p in kg/ha.
S = Sludge application rate, in dry mt/ha.
N03 = Percent nitrate-N in the sludge, as percent (e.g., 1% = 1.0).
Kv = Volatilization factor = 0.5 for surface-applied liquid
sludge, or 1.0 for incorporated liquid sludge and dewatered
sludge applied in any manner.
NH/i = Percent ammonia -N in the sludge, as percent (e.g., 2% =
2.0).
F/vear n i\ = Mineralization factor for organic N in the sludge in
^ the 'first year (from Table 6-7), expressed as a fraction
(e.g., 20% = 0.2). For example, in Table 6-7, anaerobically
digested sludge has an F factor for year 0-1 of 20% = 0.2.
Nn = Percent organic N in the sludge, as percent (e.g., 3% = 3.0).
Example of Step 1 Calculation: Assume an application rate of 5
mt/ha, dry weight, of anaerobically digested liquid sludge, which
is surface-applied. The sludge chemical analysis shows N03 = 0,
NH4 = 1.5%, and NQ = 3%, all on a dry weight basis.
6-22
-------
Np = S [(N03) + Kv (NH4) + F(year Q_^ (NQ)] (10)
= 5 [(0) + 0.5 (1.5) + (0.2) (3.0)] 10
= '67.5 kg Np/ha
The reader should note that this calculation computes the NR only
for this year's sludge application, and does not include additional
N made available from mineralization of previous years' sludge
applications, if any.
Step 2 calculates the Np available in subsequent years from "this
year's" sludge application due to the slow mineralization of NQ in the
sludges applied. The mineralization calculations for subsequent years
are demonstrated in the following example.
Assume the same sludge application rate and sludge quality as in
the previous example, i.e., 5 mt/ha application rate and 3% NQ in
the sludge on a dry weight basis.
N0 in sludge applied = (0.03) (5 mt/ha) (1,000 kg/mt) = 150 kg/ha
F factors for anaerobically digested sludge from Table 6-7 are:
Year
0-1
1-2
2-3
0.20
0.10
0.05
NQ mineralized in year 0-1 = (0.20) (150) = 30 kg/ha
NQ remaining in year 1-2 = (150) - (30) = 120 kg/ha
N0 mineralized in year 1-2 = (0.10) (120) = 12 kg/ha
NQ remaining in year 2-3 = (120) - (12) = 108 kg/ha
NQ mineralized in year 2-3 = (0.05) (108) = 5.4 kg/ha
A simpler alternate method of calculating the N0 mineralized and made
plant available in the first year and succeeding years is to use the Km
factor in Table 6-7 as shown in Equation 6-2 below:
Nm =
(5)
(6-2)
6-23
-------
where:
= Quantity of N0 mineralized in the year under consideration, in
kg/ha.
= Mineralization factor for the year under consideration (from
Table 6-7), in kg/mt/% NQ.
Nrt = Percent organic N originally present in the sludge, as percent
(e.g., 3% = 3.0).
'o
S = Sludge application rate, in mt/ha.
Example: Assume the same sludge quality and application rate as in
the previous examples, i.e., 5 mt/ha application rate and 3% NQ in
the sludge on a dry weight basis.
From Table 6-7 for anaerobically digested sludge:
Year
K,
0-1
1-2
2-3
Nm first year = (2.0) (3) (5) = 30 kg/ha
Nm second year = (0.80) (3) (5) = 12 kg/ha
Nm third year = (0.36) (3) (5) = 5.4 kg/ha
2.0
0.80
0.36
If the sludge is only applied one time, the N_ available in subsequent
years is the amount calculated in Equation 6-2. Programs which apply
sludge annually are more complex, because the NQ mineralized from all
previous years' sludge applications must be included.
Example: Assume annual application of the same quality sludge and
sludge application rate as used in the previous examples, i.e., 5
mg/ha application rate and 3% N0 in the sludge. Calculate the ND
available during each of the first 3 years. v
Year 0-1 (from Equation 6-1)
Np = S [(N03) + Kv (NH4) + F(yeap 0_1} (NQ)] (10)
= 5 [(0) + 0.5 (1.5) + (0.2) (3.0)] 10
= 67.5 kg/ha
6-24
-------
Year 1-2 (from Equations 6-1 and 6-2)
N = N from second year plus Nm from first year
Np = 67.5 + (Km) (N0) (S)
= 67.5 + (0.80) (3) (5)
= 79.5 kg/ha
Year 2-3 (from Equations 6-1 and 6-2)
ND = ND from third-year application plus Nm from second-year
v application plus Nm from third-year application
Np = 67.5 + (0.80) (3) (5) + (0.36) (3) (5)
= 84.9 kg/ha
The amount of plant available N applied to soil in sludge is determined
as described above for all three annual application rate approaches
listed at the beginning of Section 6.4.3. For Approach 1, and usually
Approach 2, the amount of plant available N applied in the sludge equals
the N required by the crop grown.
6.4.3.2 Calculation Based on Metal Limitations
The "Criteria" limit the Cd application on an annual basis, and Cd, Pb,
Zn, Cu, and Ni on a total cumulative basis for the site. In either
case, the amount of sludge that can be applied (dry weight basis) is
calculated with the same basic equation:
. _
Sm -
(1,000 kg/mt)
(6-3)
m
where:
Sm = Amount of sludge, in mt/ha, that can be applied for the metal
and time interval selected (e.g., annual for Cd, or total cum-
ulative for Cd, Pb, Zn, Cu, Ni).
L = Metal limitations, in kg/ha; see Table 6-8 for annual Cd
limit, Table 6-2 for cumulative limits.
Cm = Concentration, in mg/kg, of the metal of concern in the sludge
being applied.
See sample calculation at end of this chapter.
6-25
-------
TABLE 6-8
SUMMARY OF ANNUAL CADMIUM LIMITATIONS (10)
Type of Crop Grown
Tobacco, root crops,
leafy vegetables
Other food chain crops
(e.g., corn, small
grains, forages)
Animal feed only
Annual
Cd Limit
kg/ha (Ib/A)
0.5 (0.45)
2.0 (1.78).
1.25 (1.11V
0.5 (0.45)#
None
Comments
pH 2.6.5
pH >6.5
pH_>6.5 '
Detailed manage-
ment plan will
also be required.
* Present to 6/30/84.
t 7/1/84 to 12/31/86.
# After 1/1/87.
6.4.3.3 Calculation of Phosphorus Applied
The annual sludge application rate may also be based on the P require-
ments of the crop grown. It is assumed that the P contained in a sludge
is 50 percent as available for plant uptake as the phosphates normally
applied to soils in commercial fertilizers (e.g., super and triple super
phosphate, diammonium phosphate, etc.). As previously discussed, the P
fertilizer needs of the crop grown are determined from the soil test for
available P and the yield level of the crop grown. The amount of sludge
applied is then equated to the P fertilizer requirement:
Sp =
(1,000 kg/mt)
(6-4)
where:
Sp = Application rate of sludge, in mt/ha, to satisfy P fertilizer
H need of crop.
Cp = Plant P needs, in kg/ha.
Pn = Concentration of P in sludge, in mg/kg.
6-26
-------
Because the P needs of most crops are approximately 25 percent of the N
requirement, the amounts of sludge applied each year with Approach 3 are
considerably less than those used with the two other approaches. For
nearly all sludges, supplemental N fertilization will be needed to opti-
mize crop yields (except for N-fixing legumes). A major advantage of
this approach is that the amounts of Cd applied to soils each year will
be less than the Cd limits for nearly all sludges. This approach is the
most conservative alternative presented.
6.4.4 Calculation of Fertilizer N, P, and K
The amounts of.N, P, and K applied in the sludge should be compared to
recommended additions of fertilizer N, P, and K to achieve the yields
desired (see Tables 6-3 through 6-6). If this comparison shows that one
or more nutrients will be suboptimal, the appropriate amount of commer-
cial fertilizer can be applied. Maximum yields will not result unless
all essential plant nutrients are present at recommended levels. In
some systems, additional fertilizer may not be applied because of econ-
omic considerations.
6.4.5 Termination of Sludge Applications Based on Metal Additions
s
To protect the productivity of soils and to minimize long-term accumula-
tion of Cd in crops, sludge applications are terminated when the cumula-
tive amounts of Pb, Zn, Cu, Ni, or Cd exceed a specific limit based on
the CEC of the soil. Recommended cumulative metal loadings developed in
1977 for privately owned agricultural cropland are shown in Table 6-2.
It is imperative that the reader determine if there have been subsequent
modifications to these recommendations. As shown, soils are subdivided
into three categories based on CEC. Additional comments on total metal
limits are presented in Section 6.3.5.
The amounts of Pb, Zn, Cu, Ni, and Cd applied each year are recorded and
added to the cumulative metal additions from previous years. Sludge
applications cease when any one of the metal limits is reached. When
more intensive management and monitoring are employed, and potential
crop yield reductions and use restrictions are acceptable, the metal
limits shown in Table 6-2 may be exceeded. The dedicated disposal
option discussed in Chapter 9 is an example of such a case.
6.5 Monitoring Requirements
The conservative design approaches presented reduce the need for moni-
toring of soils, crops, and surface and ground water. Since the basic
rationale is to utilize sludge as a substitute for commercial fertilizer
materials, monitoring of ground water is not usually required, provided
that the soil is maintained at pH_MJ-5.
Typical monitoring requirements for agricultural utilization of sludge
at agronomic rates are summarized in Table 6-9. State and local regula-
tory agencies must be contacted to obtain monitoring requirements for a
specific project.
6-27
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TABLE 6-9
TYPICAL SITE MONITORING REQUIREMENTS FOR SLUDGE
APPLICATION AT OR BELOW AGRONOMIC RATES
Monitoring of:
Soil
pH
Soil Test
for P
and KT
N03~ in
Ground
Water
Cd 1n
Crop
Yes (2)# Yes (2)
No
No
* Numbers in parentheses refer to frequency of analy-
sis: 2 = every 2 years.
t Soil test for available N can be used, if appropri-
ate.
# Frequency depends on amount of N applied, depth to
ground water, and amount of leachate. Regulatory
agencies will dictate frequency.
The major parameters of concern are (1) pH maintenance at 6.5 to reduce
potential metal migration, and (2) soil P and K if optimum crop yields
are a project goal. Nitrate in ground water is generally only a problem
when the sludge application(s) exceed the N needs of the crop. If the
applied N equals crop fertilizer requirement, then potential ground
water contamination from sludge is no greater than from the use of con-
ventional fertilizers.
6.5.1 Soil pH
The "Criteria" (10) require maintenance of pH 6.5 or greater to minimize
Cd uptake by crops. This pH also reduces the potential for phytotoxi-
city and leaching of Zn, Cu, and Ni. If soil pH is less than 6.5, an
appropriate buffer method is used to determine the amount
or equivalent required for adjusting the soil to pH 6.5.
performed on a routine basis by soil testing laboratories.
6.5.2 Soil Test for P and K
6.5,
of limestone
Analyses are
Analyses are required to determine the amounts of P and K fertilizer
needed to optimize crop yields. These analyses are standardized for
each region of the United- States. In some states, recommendations for
fertilizer N are based on soil organic matter or NOo" in the soil pro-
file. These analyses should be conducted as needed.
6.5.3 Nitrate in Ground Water
A potential off-site environmental impact following sludge application
on land may be N03~ leaching into ground water. Ground water monitoring
is needed only when the amount of sludge-borne N applied exceeds the N
6-28
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needs of the crop grown. If the N applied equals crop fertilizer re-
quirement, the threat of N0o~ contamination of ground water from sludge
application is no greater tnan from the use of conventional N fertili-
zers. Additional information on ground water monitoring is presented in
Chapter 11.
6.5.4 Cadmium in Crops
Cd analysis is usually needed only when the annual or cumulative appli-
cation rate exceeds either the limitations presented in Section 6.3.4 or
state or local regulations. Cd analysis is recommended when unforeseen
land development results in conversion of non-food chain land to food
chain cropland, and where past sludge applications have exceeded the
limitations. The plant part sampled will depend on the crop grown.
Typically, the harvested portion (fruit, grain, tuber, or leaf) will be
sampled and analyzed for Cd. The actual concentration of Cd in plant
materials is somewhat meaningless in that the Food and Drug Administra-
tion (FDA) has (in 1983) not established acceptable levels of Cd in var-
ious crops. If excess Cd is applied, it is strongly recommended that
the same crop be grown on an adjacent non-sludge-treated soil of the
same type to evaluate the relative increase of Cd in the crop caused by
sludge application. The same cultivar (variety) of crop should be grown
at the two sites, because Cd uptake can vary for different cultivars.
6.5.5 Other Analyses
Additional site-specific analyses may be needed to monitor the status of
some land application systems. For example, soils may need to be ana-
lyzed for soluble salts and/or boron in semiarid regions where irriga-
tion is planned. The movement of metals and N can also be assessed by
periodically obtaining soil samples to a depth of 2 to 3 m (6 to 10 ft),
and analyzing each 30-cm (12-in) increment. Appendix C contains more
detailed information.
6.6 Sludge Application Methods and Scheduling
6.6.1 Methods of Application
Methods of sludge application on agricultural land are dependent on the
physical characteristics of the sludge and soil and the crops grown.
Liquid sludges can be applied by surface spreading or subsurface injec-
tion. Surface application methods include spreading by farm tractors,
tank wagons, special applicator vehicles equipped with flotation tires,
tank trucks, portable or fixed irrigation systems, and ridge and furrow
irrigation.
Surface application of liquid sludge is normally limited to soils with
<6 percent slopes. It is the normal procedure when forage crops are
grown. After sludge has been applied to the soil surface and allowed to
partially dry, it is commonly incorporated by plowing or disking prior
to planting the crop (i.e., corn, soybeans, small grains, cotton, other
6-29
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row crops). Ridge and furrow irrigation systems can be designed to
apply sludge during the crop growing season. Spray irrigation systems
generally should not be used to apply sludge to forages or to row crops
during the growing season. The adherence of sludge to plant vegetation
can have a detrimental effect on crop yields by reducing photosynthesis.
In addition, spray irrigation tends to increase the potential for odor
problems. Surface application of liquid sludge by ,tank trucks and ap-
plicator vehicles is the most common method for agricultural croplands.
Liquid sludges can also be injected below the soil surface. Available
equipment includes tractor-drawn tank wagons with injection shanks (ori-
ginally developed for liquid animal wastes) and tank trucks fitted with
flotation tires and injection shanks (developed for sludge application).
Both types of equipment minimize any odor problems and reduce ammonia
volatilization by immediate mixing of soil and sludge. Sludge can be
injected into soils with up to 12 percent slope. Flotation tires are
advantageous to reduce soil compaction and to allow application on soft
ground. Incorporation can be used either before planting or after har-
vesting all crops with the exception of forages. This application
method is likely to be unacceptable for forages which are cut and baled,
because some injection shanks can either ruin the forage stand or create
deep ruts in the field. Specialized equipment for injection in forage
is available.
Dewatered sludges are applied to cropland by handling equipment similar
to that used for applying animal manures, limestone, or solid fertili-
zers. Typically, the dewatered sludge will be surface-applied and then
incorporated by plowing or disking. Incorporation is not used when de-
watered sludges are applied to growing forages. Sludge application
methods are discussed in greater detail in Chapter 10.
6.6.2 Scheduling
The timing of sludge applications must correspond to farming operations,
and is influenced by crop, climate, and soil properties. Sludge cannot
be applied during periods of inclement weather. In some states, sludge
cannot be applied to soils that are frozen or covered with snow. Soil
moisture is a major consideration which impacts the timing.of sludge ap-
plication. Traffic on wet soils during or immediately following heavy
rainfalls may result in compaction and reduced crop yields; muddy soils
also make vehicle operation difficult. Application to frozen or snow-
covered ground with greater than 3 percent slope may result in excessive
runoff into adjacent streams. In addition, sludge applications must be
scheduled around the tillage, planting, and harvesting operations for
the crops grown. A general guide to allowable times for surface and
subsurface applications of sludge for North Central States is shown in
Table 6-10. Individual states or local extension personnel can provide
similar information.
Split applications of sludge may be required for rates of liquid sludge
in excess of 11 mt/ha (5 dry T/ac). Split application involves the
addition of smaller quantities of sludge at different times of the year
6-30
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TABLE 6-10
GENERAL GUIDE TO MONTHS AVAILABLE FOR SLUDGE
APPLICATION TO DIFFERENT CROPS IN NORTH CENTRAL STATES*
Small Grains'*"
Month
January
February
March
April
May
June
July
August
September
October
November
December
Corn
S*
s*
S/I
S/I
P, S/I
c
c
c
c
H, S/I
S/I
S*
Soybeans
S*
S*
S/I
S/I
P, S/I
P, S/I
C
C
H, S/I
S/I
S/I
S*
Cotton^ Forages
S/I
S/I
s/r
P, S/I
C
C
C
C
C
S/I
S/I
S/I
s*
s*
s
c
c
H, S
H, S
H, S
S
H, S
S
S*
Winter Spring
C
C
C
C
C
C
H, S/I
S/I.
S/I
P, S/I
C
C
S*
S*
s/i
P, S/I
c
c
H, S/I
S/I
s/i
s/i
S/I
s*
* Application may not be allowed due to frozen or snow-covered soils
in some states; S/I, surface or incorporated application; S, surface
application; C, growing crop present; P, crop planted; H, after crop
harvested.
t Wheat, barley, oats, or rye.
# Cotton, only grown south of southern Missouri.
** Established forages, legumes (alfalfa, clover, trefoil, etc.), grass
(orchard grass, timothy, brome, reed canary grass, etc.), or legume-
grass mixture.
6-31
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to attain the desired total rate. If the sludge contains 4 percent sol-
ids, the volume of sludge applied at a rate of 11 mt/ha (5 T/ac) is ap-
proximately 89,000 1/ha (23,500 gal ac or about 0.9 ac-in). Realizing
that surface runoff depends on soil properties (e.g., infiltration rate)
and slope, the likelihood of runoff from relatively flat soils (<5 per-
cent slope) is increased when application rates approach 100,000 1/ha (1
ac-in) of liquid sludge. Obviously, subsurface application will mini-
mize runoff from all soils. An advantage of split application is the
increased efficiency of N utilization by the crops grown.
6.6.3 Storage
Storage facilities are required to hold sludge during periods of incle-
ment weather, equipment breakdown, frozen or snow-covered ground, or
when access would damage the field or crop. Liquid sludge can be stored
in digesters, tanks, lagoons, or drying beds; dewatered sludge can be
stockpiled. Volume requirements will depend on individual systems and
climate.
The amount of storage capacity needed can be estimated from the follow-
ing data:
Sludge volume and physical
Climatological data.
Cropping data.
characteristics.
An ultraconservative design of storage capacity is for I year's produc-
tion. A more realistic storage volume can be computed from climatologi-
cal and cropping data.
6.6.3.1 Climatological Data
Sludge applications may be restricted or prohibited in some states on
days when >2.5 mm (0.1 in) of rainfall occurs, or when the soils are
frozen or snow-covered. For a specific site, the average number of days
in each month with these or other weather conditions can be obtained
from the National Climatic Center, NOAA, Asheville, North Carolina
28801, or from local sources.
6.6.3.2 Cropping Data
Except for forages, sludge application to cropland is usually limited to
those months of the year when a crop is not present. The application
schedule shown in Table 6-10 is a general guide for common crops in the
North Central States. The availability of sites used to grow a variety
of crops clearly facilitates the application of sludge throughout the
year. For example, a site containing forages, corn, and winter wheat
would permit sludge application during nearly all months of the year.
Chapter 10 contains additional information on evaluating sludge storage
needs.
6-32
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6.7 Design Example of Sludge Application Rate Calculations
A detailed design example will be developed for a midwestern city with
20 dry mt/d (22 T/d) of sewage sludge requiring disposal. The sludge
has undergone anaerobic digestion, and has the following characteris-
tics:
Solids - 4.0 percent
Total N - 2.5 percent
NH4-N - 1.0 percent
Total P - 2.0 percent
Total K - 0.5 percent
Pb - 500 mg/kg
»
«
Zn - 2,000 mg/kg
Cu - 500 mg/kg
Ni - 100 mg/kg
Cd - 50 mg/kg
PCB's - 0.5 mg/kg
Climatological data were collected for the application area as described
in Chapter 4. Sludge application will be limited during periods of high
rainfall and high soil moisture conditions, because of the potential for
surface runoff and the inability to use sludge application equipment.
Sludge application will also be limited during periods of extended sub-
freezing temperatures due to. frozen soils.
For this site, assume that:
Annual sludge applications can not exceed either the N re-
quirement for the crop grown or 2 kg Cd/ha (1.78 Ib Cd/ac).
Soil must be maintained at pH 6.5 or above.
t If the nutrient content of the sludge is not sufficient, then
supplemental fertilizer will be used to optimize crop produc-
tion.
Annual monitoring is not needed other than routine soil test-
ing to establish fertilizer recommendations and lime require-
ment.
t The sewage treatment plant monitors chemical composition of
the sludge.
Records are maintained on the amount of sludge applied to each
area.
Ground water monitoring will be needed if N applications exceed the N
needs of the crop grown. If the Cd applied exceeds the regulatory limit
(either annual or cumulative), only animal feed can be grown on the site
(10).
Soils in the site area are generally sandy loams, having a CEC of 10
meq/100 g. Representative soil analyses are as follows:
* CEC - 10 meq/100 g
Soil pH (in water) - 6.0
6-33
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Available P - 17 kg/ha (15 Ib/ac)
t Available K - 84 kg/ha (75 Ib/ac)
Lime (to pH 6.5) - 5.4 mt/ha (2.4 T/ac)
Crops grown in the area include corn, soybeans, oats, wheat, and forages
for hay and pasture. One half of the site is cropped with forages re-
quiring 390 kg/ha (350 Ib/ac) of available N per year, and one half is
cropped with corn requiring 190 kg/ha (170 Ib/ac) available N per year.
Crop fertilizer requirements were obtained from Tables 6-2 and 6-5.
Fertilizer recommendations for the two crops are as follows:
N P K
Crop
Corn
Forage
Yield (T/ha)
8.4-10.1
2.7
(kg/ha/year)
190
390
45
59
140
336
P and K recommendations are based on the soil test data shown above.
6.7.1 Calculation of Initial Annual Sludge Application Rates for
Nitrogen
The ND in the anaerobically digested sludge is calculated based on 100
percent availability of NH4-N and 20 percent availability of organic N
(F = 0.20) during the year of sludge application (see Table 6-7). The
sludge does not contain detectable amounts of NOo-N, so only NH^-N and
total N are needed to determine the Np. Equation 6-1 is used for this
calculation:
Np = S [N03 + Kv (NH4) + F(year Q_1} (NQ)] (10)
Let S (sludge application rate) = 1 mt/ha, then:
Np = (1) [(0) + (1) (1) -i- (0.20) (2.5 - 1.0)] (10)
= 13 kg/mt sludge applied to corn
The above calculation is for corn where the sludge is incorporated, mak-
ing the Ky volatilization factor = 1.
Sludge will be surface-applied on the forage crop, so there will be
volatilization losses (Ky = 0.5). For this case:
Np = (1) C(O) + (0.5) (1) + (0.20) (2.5 - 1.0)] (10)
= 8 kg/mt sludge applied to forage
6-34
-------
The sludge application rate required to deliver this amount of N to the
crop in the initial year of application can be calculated by substitut-
ing the appropriate N values in Equation 6-3.
c _
SN -
Corn (190,kg N/ha/year):
SM =
190 kg/ha/yr
13 kg N /mt sludge
Forage (390 kg N/ha/year):
= 14.6 mt sludge/ha
_ 390 kg/ha/yr
8 kg N /mt sludge
= 48.8 mt sludge/ha
These values are the N-limiting rates for the first year only. In sub-
sequent years, a portion of the previously applied organic N will be
mineralized and will become available for plant uptake. (See Section
6.4.3.1 for a discussion and sample calculation.)
6.7.2 Calculation of
Limitation
Annual Sludge Application Rates Using Cadmium
In addition to considering the annual rate of N addition, the rate of Cd
application must be below the prevailing limit if a food chain crop is
grown. Assume that the application regulations state that the maximum
amount of Cd applied is limited as shown in Table 6-8. The maximum
annual sludge application rate is calculated using Equation 6-3 with the
appropriate Cd values:
"Cd
:Cd
(1,000 kg/mt)
Ccd = 50 mg/kg
Present to June 30, 1984:
Lcd = 2.0 kg/ha/year
6-35
-------
cd
= (2)
= 40 mt/ha/year
July 1, 1984, to December 31, 1986:
Lcd = 1.25 kg/ha/year
SCd (1.25^(1,000) . 25 mt/ha/year
After January 1, 1987:
LCc( = 0.5 kg/ha/year
«t/ha/year
These Cd limits apply to both the corn and forage
assumed that the latter will enter the food chain as
crops,
animal
since
feed.
it is
A comparison of the sludge application rates based on N and Cd indicates
the following:
Corn - Application of 14.6 mt/ha will
limit until January 1, 1987.
not exceed the annual Cd
Forage - Application of 48.8 mt/ha exceeds the current and
future Cd limits. Sludge use on forage is limited to 40 mt/
ha, resulting in the need for additional N fertilizer to
attain optimum yields. The annual application rate will de-
crease to 25 mt/ha and ultimately to 10 mt/ha.
In all cases, the soil
the sludge is applied.
pH must be maintained at 6.5 or above whenever
6.7.3 Calculation of Annual Sludge Application and Supplemental
Fertilizer Rates for Multi-Year System
The annual application rate based on N required by the crop is calcu-
lated after correction of the amount of organic N mineralized from prior
sludge applications. The application rate based on N and the associated
amount of Cd applied is then compared to the prevailing limitation on Cd
additions. The smaller application rate of the two is selected and is
used to compute amounts of fertilizer needed to optimize crop yield.
6-36
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6.7.3.1 Calculation of Annual Application Rate with Correction
for Residual Mineralized N
N required by corn = 190 kg N/ha/year
Plant available N in sludge = 13 kg N /mt sludge
The mineralized N calculation results are shown for the first 5 years of
a sludge utilization system. Assume that initial sludge application is
made in 1982, so residual N must be evaluated in 1983. The method is
described in Section 6.4.3.1.
For example, if the sludge loading rate = 14.6 mt/ha, initial organic
N = 1.5 percent, mineralization rate first year ("F" factor from Table
6-7) = 0.20, and mineralization rate second year = 0.10, then:
Initial organic N in sludge = (0.015) (14.6 mt/ha) (1,000 kg/mt)
= 219 kg/ha
Amount mineralized during application year = (219) (0.20)
= 43.8 kg/ha
Residual at end of application year = 219 - 43.8
= 175.2 kg/ha
Mineralized in second year - (175) (0.10)
= 17.5 kg/ha. ' '
The same results can be obtained by using the (kg N/mt 1% N_) factors
(Factor Km) in Table 6-7. For example, the second year 1^ factor for
this sludge would be 0.8, and the amount of organic N mineralized would
be: ; ,
Mineralized N = (Sludge Loading, -^) (% Organic, N in Sludge) (Kj
(14.6 mt/ha) (1.5% organic N) (0.8) = 17.5 kg/ha
Mineralized
N in
1982
1983
1984
1985
1986.
Mineral ized
N (kg/ha)
0
17.5
23.7
27.1
30.3
6-37
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6*7.3.2 Fertilizer P Needed for Optimum Corn Crop
Corn needs 45 kg P/ha. Assuming 50 percent of sludge P is available,
then:
P available = (0.02 P) (0.50 available) (1,000 kg/mt)
= 10 kg P available/mt sludge
Year
1982
1983
1984
1985
1986
Sludge
Applied
(mt/ha)
14.6
13.2
12.8
12.5
12.3
Calculation
45
kg P/ha - (14.6 mt/ha x 10 kg Pp/mt)
45 kg P/ha - (13.2 mt/ha x 10 kg P /mt)
45 kg P/ha - (12.8 mt/ha x 10 kg Pp/mt)
45 kg P/ha - (12.5 mt/ha x 10 kg Pp/mt)
45 kg P/ha - (12.3 mt/ha x 10 kg P /mt)
Fertilizer
P (kg P/ha)
-101
-87
-83
-80
-78
The minus (-) value indicates that P additions from sludge are in excess
of crop requirements.
6.7.3.3 Fertilizer K Needed for Optimum Corn Crop
Corn needs 140 kg K/ha. Assuming all K in sludge is available to the
crop, then:
K available = (0.005) (1,000 kg/mt)
= 5 kg Kp/mt sludge
Year
1982
1983
1984
1985
1986
Sludge
Applied
(mt/ha)
14.6
13.2
12.8
12.5
12.3
Calculation
140 kg K/ha - (14.6 mt/ha x 5 kg Kp/mt)
140 kg K/ha - (13.2 mt/ha x 5 kg !
-------
6.7.3.4 Forage - Sludge Application Rate Limited by Cd
It was determined that the initial application rate of sludge on forages
would be 48.8 mt/ha, based on N need. In 1982, this application rate
would exceed the Cd limitation of 2 kg/ha. Since the Cd limit decreases
in 1984 to 1.25 kg/ha and then to 0.5 kg/ha in 1987, it is obvious that
sludge use on forages will provide only a portion of the N required to
optimize yield. The amount of sludge applied, based on Cd limits of 2,
1.25, and 0.5 kg/ha, are 40, 25, and 10 mt/ha, respectively. The ini-
tial limit will apply to 1982 and 1983, while the intermediate limit
will be used for 1984 to 1986. Fertilizer N, P, and K applications will
be computed for a 5-year system.
N required by forage = 390 kg N/ha
Plant available N in sludge = 8 kg Np/mt
(surface application)
Mineralized kg N/ha = mt sludge/ha x % organic N in sludge x kg Np
mineralized/metric for sludge/% organic N
The fraction of organic N mineralized is obtained from Table 6-7, Factor
K. The amount mineralized each year is summarized below:
m.
Mineralized
N in
1982
1983
1984
1985
1986
Mineralized
N (kg/ha)
0
48
70
65
69
6.7.3.5 Fertilizer N Needed for Optimum Forage Crop
Fertilizer N needs can be determined by correcting the N requirement of
forage for mineralized organic N and sludge N applied as shown below.
(C) (A)-(B+C)
,
v Fertilizer
Sludge N Applied (kg N/ha) (kg N/ha)
40 mt/ha x 8 kg N /mt = 320 70
40 mt/ha x 8 kg Np/mt = 320 22
25 mt/ha x 8 kg Np/mt = 200 120
25 mt/ha x 8 kg N /mt = 200 125
25 mt/ha x 8 kg N /mt = 200 121
Year
1982
1983
1984
1985
1986
(A)
Crop
Requirement
(kg N/ha)
390
390
390
390
390
(B)
Mineralized
(kg N/ha)
0
48
70
65
69
6-39
-------
6.7.3.6 Calculation of Fertilizer P and K Needs for Optimum
Forage Crop
P needed by forage = 59 kg/ha
Plant available P in sludge = - x 0.5 x 1,000
x 0.5 x 1,000
=10 kg Pp/mt
kg fertilizer P/ha = kg P needed/ha - (mt sludge/ha x kg P /mt)
Year
1982
1983
1984
1985
1986
Sludge
Applied
(mt/ha)
40
40
25
25
25
Calculation
59 kg P/ha - (40 mt/ha x 10 kt Pp/mt)
59 kg P/ha - (40 mt/ha x 10 kg P /mt)
59 kg P/ha - (25 mt/ha x 10 kg Pp/mt)
59 kg P/ha - (25 mt/ha x 10 kg Pp/mt)
59 kg P/ha - (25 mt/ha x 10 kg Pp/mt)
K needed by forage = 336 kg/ha
Plant available K in sludge =
x 1,000
Fertilizer
P (kg P/ha)
-341
-341
-191
-191
-191
= 5 kg Kp/mt
Year
1982
1983
1984
1985
1986
Sludge
Applied
(mt/ha)
40
40
25
25
25
Calculation
336 kg/ha - (40 mt/ha x 5 kg Kp/mt)
336 kg/ha - (40 mt/ha x 5 kg K /mt)
336 kg/ha - (25 mt/ha x 5 kg Kp/mt)
336 kg/ha - (25 mt/ha x 5 kg Kp/mt)
336 kg/ha - (40 mt/ha x 5 kg K /mt)
Fertilizer
K (kg K/ha)
136
136
211
211
211
6-40
-------
6.7.4 Sludge Application Rate Limited by Phosphorus
The annual rate of sludge application can also be calculated from the P
crop needs (some states require this approach). For the soil selected,
the fertilizer.? needs of corn and forage are 45 and 59 kg/ha, respec-
tively. The annual rates are calculated as follows from the plant
available P content of the sludge:
""available = (% p 1n slud9e) (50% availability)
(Note: Assumes that 0.5 of the total P in sludge is equivalent to con-
ventional P fertilizers with respect to plant availability.)
For this sludge:
Pp = (0.02) (0.50) (1,000) = 10 kg/mt
Equation 6-3 then gives the annual sludge rate as follows:
C_
SP = P
For corn:
For forage:
_ (45 kg P/ha)
) (10 kg/mt)
=4.5 mt/ha
S,, =
59 kg P/ha
10 kg/mt
= 5.9 mt/ha
The amounts of Cd applied to corn and forage would be 0.1 and 0.14
kg/ha, respectively. These Cd additions are significantly less than
both the 1982 and future Cd limitations.
6-41
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6.7.4.1 Calculation of N and K Fertilizer Needs for
Phosphorus Limiting Design
The annual application rates limited by the P needs for corn and forage
are 4.5 and 5.9 mt/ha, respectively. Since these rates are very simi-
lar, the calculation of fertilizer N and K will be shown for only corn.
In addition, a precise calculation of fertilizer N would include a cor-
rection for residual N released from previous sludge applications. The
data needed are:
Annual application rate =4.5 mt/ha
N required by corn = 190 kg N/ha
Plant available N in sludge = 13 kg Np/mt sludge
K required by corn = 140 kg K/ha
Since the sludge application rate is a constant, the amount of N applied
will be the same each year:
13 kg Np/mt x 4.5 mt/ha = 58 kg Np/ha
The mineralized N and fertilizer N needed are calculated from:
Mineralized kg N/ha = mt/ha x % organic N in sludge x (kg Np
mineralized/mt sludge/% organic N)
The fraction (Km) of organic N mineralized is obtained from Table 6-7.
The amount mineralized each year is summarized below:
Mineralized
N in
1982
1983
1984
1985
1986
Mineralized
N (kg/ha)
0
5
7
8
9
Fertilizer N calculations would then involve:
kg fertilizer N/ha = kg N required by crop/ha - kg sludge
N added/ha - kg residual N/ha
6-42
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Year
1982
1983
1984
1985
1986
N Needed
by Crop
(kg N/ha)
190
190
190
190
190
SI udge
Inorganic
N Added
(kg N/ha)
58
58
58
58
58
Residual
.N (kg/ha)
0
5
7
8
9
Fertilizer
N Needed
(kg/ha)
132
127
125
123
It is obvious that the amount of fertilizer N needed each year is essen-
tially constant, and will average approximately 125 kg N/ha/year. In
view of the uncertainties involved in establishing N fertilizer recom-
mendations, the residual N correction does not need to be used when
annual application rates are based on the P needs ,of the crop.
A single calculation is used to determine the amount of fertilizer K
needed because the sludge application rate is constant:
Fertilizer K/ha = kg K needed by crop/ha -
x mt sludge/ha
% K
= 140 kg K/ha -
=140-22
= 118 kg/ha
x 4.5 mt/ha x 1,000
6.7.5, Calculations
Application
of Total Cumulative Amount of Sludge
The total amount of sludge that can be applied for the life of a site is
based on the cumulative metal loadings, as calculated from the metal
content of the sludge and the cumulative metal limits shown in Table 6-
2. The maximum amount of sludge which can be applied during the design
life of the site is calculated with Equation 6-3:
m
= ^L (1,000 kg/mt)
m
For lead:
>Pb
Pb
(1,000 kg/mt)
6-43
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(1,000 kg/mt)
= 2,240 mt/ha
For the sludge in this example:
Metal
Pb
Zn
Cu
Ni
Cd
Total
Metal
Limit
(kg/ha)
1,120
560
280
280
10
Metal
Content
of Sludge
(rag/kg)
500
3,000
500
200
50
Calculation
luir x 100°
folio x 100°
280 x ionn
500 x iuuu
280 x innn
200 X iUUU
f£ x 1000
Total Amount
of Sludge
Al 1 owed
(mt/ha)
2,240
187
560
1,400
200
In this case, Zn will limit the total cumulative sludge loading to 187
mt/ha. The site life is then a function of the loading rates previously
derived.
For corn, the average rate after the first 2 years is about 12 mt/ha per
year. The useful life would then be 187/12, or 15.6 years.
For forages, the rate was controlled by Cd and ranged from 40 mt in 1982
to 10 mt in 1987. On that basis, the useful life would be about 8
years.
6.7.5.1 Phosphorus Limiting Design
The sludge loading rate was 4.5 mt/ha for corn and 5.9 mt/ha for for-
ages. The useful life is then as follows:
Corn
Forages
= 41.5 years
= 31.7 years
6-44
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6.7.6 Area Requirement
The amount of sludge produced per year is 6,600 mt, of which 50 percent
is to be applied to corn and 50 percent to forage.
6.7.6.1 N and Cd Basis
a. Corn - Incorporated Application
Area needed .
275 ha
b. Forage - Surface Application
From 1982 to 1983:
Acreage needed! « 3,>30° m,t/y,r = 82.5 ha
40 mt/ha/yr
In 1984 and 1985:
Acreage needed = 3.300 mt/yr = 13£ ha
25 mt/ha/yr
6.7.6.2 P Basis
a. Corn - Incorporated Application
Acreage needed - 767 ha
b. Forage - Surface Application
Acrea9e needed .
6. 7.7 Storage
-559 ha
As with virtually all agricultural land sludge application programs,
sludge storage facilities will be required for this design example.
Chapter 10 contains a discussion of the factors used to estimate re-
quired sludge storage capacity. State regulatory agencies will some-
times stipulate the minimum number of days of sludge storage. required.
6-45
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6.7.8 Application Scheduling and Operations
Table 6-11 presents a possible schedule for a typical midwestern city to
apply sludge to corn and forage crops. The table shows that no sludge
application can be made during the period December through February.
Sludge application to forage can be made from March through November,
and sludge can be applied to corn in March, April, October, and Novem-
ber.
TABLE 6-11
TYPICAL MONTHS OF THE YEAR WHEN SLUDGE CAN BE
APPLIED TO CORN AND FORAGE FOR DESIGN EXAMPLE
Month
Corn
Forage
January
February
March
April
May
June
July
August
September
October
November
December
NA
NA
SI
SI
C
C
C
C
C
SI
SI
NA
NA
NA
S
S
S
S
S
S
S
S
S
NA
NA = no application (e.g., frozen ground); S = surface application;
SI = surface or injection application; C = growing crop present.
6.7.8.1 Transportation and Application Methods
After deciding upon an area for sludge application, the various alterna-
tives for transportation and application methods can be considered.
Costs for transportation can be estimated from data presented in Chapter
10.
6.7.8.2 Monitoring
This design example is based on minimizing both NOg-N movement into
ground water and Cd uptake by plants. Therefore, monitoring for these
parameters should not be necessary. The monitoring program would con-
sist of continuing soil analysis every 2 to 4 years for plant available
P and K and lime requirement. To preclude excessive plant availability
of metals, primarily Cd, the soil must be maintained at pH >6.5.
6-46
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6.7.8.3 Additional Cropping Patterns
To simplify the design example, only two crops were considered. How-
ever, in many situations, sludge can be applied to more than two crops.
It is suggested that application rate calculations be made for all crops
grown when a detailed plan is developed. For this design example, addi-
tional crops could be wheat, oats, barley, and soybeans. Crop rotations
are commonly used in many areas :(e.g., corn-soybeans, soybeans-winter
wheat, and forage-corn-oats-forage).
6.8 References
1. Land Application of Waste Materials.
America, Ankeny, Iowa, 1976. 319 pp.
Soil Conservation Society of
2. Knezek, B. D., and R. H. Miller, eds. Application of Sludges and
Wastewaters on Agricultural Land: A Planning and Educational
Guide. North Central Regional Research Publication No. 235, Ohio
Agricultural Research and Development Center, Wooster, 1976. 88
pp.
3. Jacobs, L. W., ed. Utilizing Municipal Sewage Wastewaters and
Sludges on Land for Agricultural Production. North Central Region
Extension Publication No. 52, Michigan State University, East Lans-
ing, November 1977. 79 pp.
4. Elliott, L. F., and F. J. Stevenson, eds. Soils for Management of
Organic Wastes and Wastewaters. Soil Science Society of America
Madison, Wisconsin. 1977.
5. Conference on Recycling Treated Municipal Wastewater and Sludge
Through Forest and Cropland. Sopper, W. E., and L. T. Kardos, eds.
EPA 660/2-74-003, Pennsylvania State University Press, University
Park, 1973. 471 pp.
6. U.S. EPA. Municipal Sludge Management: Environmental Factors.
EPA 430/9-77-004, U.S. Environmental Protection Agency, Washington,
D.C., October 1977. (Available from National Technical Information
Service, Springfield, Virginia, PB-277 622)
7. Keeney, D. R., K. W. Lee, and L. M. Walsh. Guidelines for the
Application of Wastewater Sludge to Agricultural Land in Wisconsin.
Technical Bulletin 88, Madison Department of Natural Resources,
Wisconsin. 1975. 36pp.
8. Council for Agricultural Science and Technology. Application of
Sewage Sludge to Cropland: Appraisal of Potential Hazards of the
Heavy Metals to Plants and Animals. EPA 430/9-76-013, Ames, Iowa,
November 1976. (Available from National Technical Information Ser-
vice, Springfield, Virginia, PB-264 015)
6-47
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9. U.S. EPA. Sludge Treatment and Disposal. Volume 2. EPA 625/4-78-
012, U.S. Environmental Protection Agency, Cincinnati, Ohio, Octo-
ber 1978. 155 pp. (Available from National Technical Information
Service, Springfield, Virginia, PB-299 594)
10. Criteria for Classification of Solid Waste Disposal Facilities and
Practices (40 CFR, Part 257), Federal Register, 44:53438-53468.
September 13, 1979.
11.
12.
13.
Sommers, L. E., C. F. Parker, and 6. J. Meyers. Volatilization,
Plant Uptake and Mineralization of Nitrogen in Soils Treated with
Sewage Sludge. Technical Report 133, Purdue University Water Re-
sources Research Center, West Lafayette, Indiana, 1981.
Sommers, L. E., D. W. Nelson, and C. D. Spies. Use of Sewage
Sludge in Crop Production. AY-240, Purdue University Cooperative
Extension Service, West Lafayette, Indiana, 1980.
Pratt, P. F., F. E. Broadbent,
Wastes as Nitrogen Fertilizers.
and J. P. Martin. Using Organic
Calif. Agric., 34:10-13, 1973.
14. Council for Agricultural Science and Technology. Effects of Sewage
Sludge on Cadmium and Zinc Content of Crops. EPA 60018-81-003,
Ames, Iowa, February 1981. 91 pp. (Available from National Tech-
nical Information Service, Springfield, Virginia, PB81 181596)
15. Ryan, J. A., and H. Pahren. Factors Affecting
Heavy Metals from Land Application of Residuals.
of the National Conference on Disposal of Residues
ber 1976, St Louis, pp. 98-105.
16. Irrigation of Agricultural Lands. R. M. Hagan, H.
M. Edminster, eds. American Society of Agronomy,
sin. 1967.
Plant Uptake of
In: Proceedings
on Land, Septem-
R. Haise, and T.
Madison, Wiscon-
17. Hazardous Water Management System - General (Federal Register,
45:33066-33082), and Identification and Listing of Hazardous Wastes
(Federal Register, 45:33084-33133), 1980.
18. Land Application of Municipal Sewage Sludge for the Production of
Fruits and Vegetables, a Statement of Federal Policy and Guidance.
SW-905. U.S. Environmental Protection Agency, Washington, D.C.,
1981. 25 pp.
6-48
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CHAPTER 7
PROCESS DESIGN FOR FOREST LAND UTILIZATION
7.1 General
The purpose of this chapter is to present design information for the
utilization of sewage sludge on forest land. All of the information
provided was derived from research, demonstration projects, experience
with agricultural crops, and extrapolation of research experience. In
1982, there were no operating full-scale sludge-to-forest land programs
identified in the United States. However, the cities of Seattle and
Bremerton, Washington, were in advanced planning stages for such pro-
grams, and the interested reader may wish to contact these cities in the
future for operational information. Operational research and demonstra-
tion projects were also located in Washington, Michigan, and South Caro-
lina (see Table 7-1).
In 1982, no federal regulations existed which specifically addressed the
application of sludge to forest lands beyond the general requirements of
40 CFR 257. Several states (e.g., Michigan, New York, Minnesota, Wash-
ington, and Oregon) were developing proposed regulations. Project plan-
ners and designers are advised to obtain applicable regulatory informa-
tion from appropriate state and federal agencies. The design approach
taken in this chapter assumes that the chemical, biological, and physi-
cal reactions of sludge and soil in forest applications are generally
similar to those in agricultural applications (see Chapter 6).
Based on demonstration and research results, properly managed applica-
tion of sludge to forest lands is feasible. Trees have been shown to
respond positively to nutrient additions, especially when forest soils
are low in N, and surface litter layers have comparatively high N stor-
age (immobilization) capacity. Because forests are perennial, applica-
tion scheduling is often more flexible, and less sludge storage is re-
quired than with the agricultural option. Finally, in many regions,
forest land is extensive, and provides a reasonable sludge application
alternative to agricultural cropland.
Application of sludge to forest land is feasible on commercial timber
and fiber production lands, federal and state forests, and privately
owned woodlots. Sludge use in nurseries, green belt management, and
Christmas tree production is also possible, but will not be specifically
addressed in this chapter.
Sludge applications to forest land will be discussed for three common
situations: (1) recently cleared forest land that has not been planted,
(2) young plantations (planted or coppice), and (3) established forest
stands. Each of these cases presents different design problems and op-
portunities which must be considered.
7-1
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TABLE 7-1
SELECTED SLUDGE-TO-FOREST LAND RESEARCH AND
DEMONSTRATION PROJECTS (1982)
Locations and
Agency Contacts
Atlanta, Michigan
(Department of Natural
Resources, Municipal
Wastewater Division
Lansing, Michigan)
Cadillac, Michigan
(USDA Forest Service
1407 S. Harrison Road
E. Lansing, Michigan)
Elbert County, Georgia
(USDA Forest Service
Carl ton Street
Athens, Georgia)
Savannah River Laboratory
(Alken, South Carolina
Savannah River Lab
733-11A
Alken, South Carolina)
Pack Forest
(College of Forest Resources
University of Washington
Seattle, Washington)
Seattle, Washington
(Municipality of Metro-
politan Seattle)
Zanesville State Tree
(Nursery, Ohio Dept. of
Forestry
OARDC
Wooster, Ohio)
City of Hagerstown
(Hagerstown, Maryland)
Bremerton, Washington
(College of Forest
Resources, University of
Washington, Se.attle,
Washington)
Brief Description
1 application of 11 mt/ha
sludge to 6 ha (15 ac) nor-
thern hardwoods, aspen
sprouts, jack pine plantation
and pole-size oak.
1-2 applications of a range
of sludge dosages to exper-
imental plots in aspen, pine
plantings, and clearcuts.
Single application at 10
mt/ha to 24 ha (60 ac) of
cutover jack pine, 1978-
1979.
Single sludge application in
1980 to 5 ha (12 ac) cutover
jack pine for wildlife habi-
tat effect studies.
Sludge application to an
eroded forest site, approxi-
mately 2 ha, at varying
rates up to 69 mt/ha, species
are loblolly and short leaf
pine.
Extensive sludge application
R&D program, site is approxi-
mately 15 ha, using various
ages and species of trees,
varying types and application
rates of sludge up to 700 kg
N/ha dry weight.
Sludge application to Pack
Forest as well as exten-
sive green house studies
species native to the Paci-
fic Northwest.
Application of sludge to test
plots in forest lands since
1973.
Sludge application to Christ-
mas tree production plots.
Sludge application to hybrid
poplars, to be used for
electricity production.
Sludge application to forest
land (53 ha) research pro-
gram begun in 1971.
References
Study in progress
12, 23, 84
23
Study in progress
24
22
63
52
Pilot-scale proj-
ect and scale-up
in progress
7-2
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Public participation considerations are a critical aspect of planning
for forested systems. Chapter 3 contains a detailed discussion on this
topic.
7.2 Site Investigations and Selection Criteria
Chapter 5 of this manual discussed in detail the process involved in the
identification, evaluation, and selection of sites for land application
of sludge. This chapter will discuss those special aspects unique to
use of forested lands for sludge. Data sources are the same as those
described in Chapter 5, and typically include topographic maps, soil
surveys and maps, soil chemical characteristics, and site observations.
7.2.1 Physical Features
The physical features to consider include:
Proximity to public access, e.g., recreational areas, inhab-
ited dwellings, public roads, hiking trails, etc. The sludge
application site(s) should be as distant from normal public
access as practical. Many states have regulations for minimum
setbacks (buffer zones) which were developed for agricultural
sludge application. Applicable state and/or local regulations
should be reviewed. Table 5-7 in Chapter 5 summarizes sug-
gested setback distances for agricultural sludge application
sites. Except perhaps in the case of cleared land, forest ap-
plications are virtually always surface applications, and the
criteria in Table 5-7 for that case can generally apply to
forested sites.
Proximity to surface waters (e.g., ponds, lakes, springs,
creeks, streams, rivers, etc.). The sludge application
site(s) should be located and managed to avoid contamination
of surface waters. Various states require setbacks of 90 to
450 m (300 to 1,500 ft) from the 10-year high water mark of
such existing surface waters. The purpose of the setback is
to prevent sludge constituents from migrating from the appli-
cation site to the surface waters. If the application site
has steep slopes and/or relatively impervious soil, runoff
will be greater and setback distances should be increased.
Conversely, a flatter site (e.g., less than 6 percent slope)
with good soil permeability and heavy vegetation will limit
sludge constituent movement, and less setback is necessary.
Proximity to watersheds used for drinking water supplies'.
These areas should generally be avoided for sludge applica-
tion. Where conditions dictate use of water supply sensitive
sites, special provisions should be made in the program for
sludge quality control, minimization of sludge constituent
migration, and monitoring of surface and ground water quality.
7-3
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Proximity to water supply wells. Depending upon the geology
in the area, a minimum setback distance of 90 to 450 m (300 to
1,500 ft) is suggested.
Distance to ground water table. It is suggested that appli-
cation sites have a minimum ground water table of 1m (3 ft)
average, and 0.7 m (2 ft) minimum below the soil surface. The
purpose of this stipulation is to prevent seasonal surface
flooding (i.e., boggy conditions), which could cause sludge
migration. If the ground water is a drinking water aquifer,
it is suggested that the minimum distance to the seasonal high
water table be increased to 2 m (6 ft) below the soil surface,
in order to minimize leaching of sludge contaminants into the
aquifer.
7.2.2 Topography
The slope of the land surface is a major factor influencing the poten-
tial for surface runoff following sludge application. Table 5-2 in
Chapter 5 presents recommended slope criteria.
7.2.3 Soil Characteristics
7.2.3.1 Soil pH
Forest soils are typically more acidic than agricultural sites; soil pH
values of 5.5 and lower are common. For agricultural applications, the
EPA and many states require that the pH must be at or above 6.5. This
pH limit is stipulated because trace metal availability in the soil
rapidly increases as soil pH decreases. Increased metal availability in
agricultural soils increases crop .uptake of metals, possibly resulting
in plant phytotoxicity and/or the unsuitability of the crop for human
consumption. In addition, metal migration into aquifers could result
when soil pH is low.
established for-
to lower soil pH
(45)(84).
Experience with sludge applications to forest soils in
ests indicates that the increased metals available due
do not cause phytotoxicity in most forest plant species
In addition, because forest products are not food chain crops, increased
metal content of the plants themselves is not a concern for public
health. For these reasons, the appropriate regulatory agency can be
asked to waive the 6.5 soil pH lower limit, if there is no danger of
trace metal migration to u-seful aquifers.
7.2.3.2 Nutrient Availability
Forest soils, particularly in the Pacific Northwest, can be deficient in
organic nutrients, and are low in available N. In some special cases,
it may be possible to make up this original deficit with an additional
amount of sludge organic N without adverse impacts on the ground water.
7-4
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7.3 Constraints
The major constraints associated with application of sludge to forest
lands are related to specific sludge constituents, including pathogens,
N, and metals. Each of these sludge constituents is discussed in the
following subsections in relation to proper system design and management
needed to protect public health and application site ecology. The con-
straints discussed herein are adapted, where applicable, from agricul-
tural sludge application criteria, experience with demonstration proj-
ects, and opinions of experts involved in preparation and review of this
manual.
7.3.1 Pathogens
Pathogens are discussed in Appendix A. Sludge application to forest
soil, following the criteria in Section 7.2.1, should pose minimal path-
ogen contamination danger to ground water supplies.
Prevention of surface water contamination depends on the selection and
proper operation of application sites. Desirable characteristics are as
fol1ows:
Distant from sensitive surface water resources.
Experience little surface runoff because of:
- Relatively flat slopes
- Permeable soil
- No steep clearcuts
- Forest canopy which
- Forest debris layer
intecepts rainfall
at the soil surface.
Another pathogen-related concern involves windborne contamination re-
sulting from spray application of liquid sludge on forest lands. It is
suggested that the following constraints be used during spray applica-
tion of sludge to forest lands:
The public be restricted from an area at least 490 m (1,500
ft) downwind during the spray application, and for several
hours after spraying is completed.
Sludge spraying not be performed during winds of more than 24
km/hr (15 mi/hr); windless conditions are preferred.
It is obvious that aerosols will not travel far in an established forest
that is not dormant, because of interception by the leaves and breakup
of wind currents, and the suggested constraints listed above may be mod-
ified. Public access to the application site has been limited for a
period of 12 months following liquid sludge application at projects in
Michigan and Washington.
7-5
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7.3.2 Nitrogen
7.3.2.1 General
The application rate calculation based on N involves the following
steps:
1. Calculate the quantity of inorganic N (NH4 and N03) per ton in
sludge (Section 6.4).
2. Calculate the quantity of organic N per ton in sludge, and es-
timate the mineralization rate of the organic N in the first
year after application and in succeeding years (Section 6.4).
3. Tabulate the N additions represented by Items 1 and 2 above.
4. Estimate the N uptake by trees and other forest vegetation in
terms of kg/ha (Ib/ac) (Table 7-2).
5. Estimate the ammonia volatilization in terms of percent of am-
monia N (NH3) applied (Chapter 6).
6. Tabulate the N removals represented by Items 4 and 5 above, for
the first year and succeeding years in terms of kg of N re-
moved/ha (Ib/ac).
7. Determine the allowable nitrogen input to the groundwater at
the project boundary. In special cases, drinking water limits
may prevail.
8. Calculate the quantity of sludge which can be applied to the
site without exceeding the capacity of the site to remove the
necessary amount of N in the applied sludge. In cases where
ground water is not used for human consumption, or where the
aquifer is large enough to quickly dilute nitrates leaching at
the application site,-.the N loading to the site may be in-
creased. Each case should be evaluated in a site-specific man-
ner.
7.3.2.2 Nitrogen Uptake by Trees and Other Forest Vegetation
There is a significant difference between tree species in their uptake
of available N. In addition, there is a large difference between the N
uptake by seedlings, vigorously growing trees, and mature trees. Fin-
ally, the extent of the vegetative understory on the forest floor will
affect the uptake of N, i.e., dense understory vegetation markedly in-
creases N uptake.
In a forest ecosystem, much of the N uptake by the trees is returned to
the soil as needle, leaves, and litter fall. Thus, the net N uptake is
usually significantly less than the gross N uptake by the growing trees
and understory.
7-6
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TABLE 7-2
ESTIMATED ANNUAL NITROGEN REMOVAL BY FOREST TYPES (81)'
Eastern Forests
Mixed Hardwoods
Red Pine
Old Field with White
Spruce Plantation
r'
Pioneer Succession
Aspen Sprouts
Southern Forests
Mixed Hardwoods
Southern Pine with No
Understory#
Southern Pine with
Understory#
Lake State Forests
Mixed Hardwoods
Hybrid Poplar
Western Forests
Hybrid Poplar
Douglas Fir Plantation
Tree Age
(years)
40-60
25
15
5-15
40-60
20
20
50
5
4-5
15-25
Average Annual
Nitrogen Uptake
(kg/ha/yr)t
200
100
200
200
100
280
200
260
100
150
300
200
* Uptake rates shown are for wastewater irrigated forest stands.
t Conversion factor kg/ha = 0.89 Ib/ac.
# Principal southern pine included in these estimates is loblolly
pine.
** Short-term rotation with harvesting at 4 to 5 years; represents
first growth cycle from planted seedlings.
Table 7-2 provides estimates of annual N uptake by the overstory and un-
derstory vegetation of fully established and vigorously growing forest
ecosystems in selected regions of the United States. The average annual
N uptakes reported vary from 100 to 400 kg/ha/year (89 to 356 Ib/ac/
year), depending upon species, age, etc. Note that all of the trees
listed in the table are at least 5 years old, and that during initial
stages of growth, tree seedlings will have relatively lower N uptake
rates than shown. Net N uptake may be only 5 to 50 percent of that
shown in Table 7-2.
7-7
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7.3.2.3 Nitrification-Denitrification Reactions
Nitrogen loss by denitrification is discussed in detail in Appendix B of
this manual. Generally, little N removal by denitrification is expected
in typical well drained forest soils.
7.3.2.4 Ammonia Volatilization
For design purposes, volatilization losses can be estimated at 50 per-
cent of the ammonia N applied to the soil surface in liquid sludges; the
entire loss occurs in the first year after application. If liquid
sludge is incorporated or if dewatered sludges are applied, the design
should not assume any specific losses via volatilization.
However, based on wastewater irrigation experience, it can be shown that
10 to 15 percent of the inorganic N applied each year cannot be ac-
counted for. The assumed pathways are volatilization and denitrifica-
tion losses. It is reasonable to expect a similar level of loss from
sludge applications. However, these losses are hot additive, so that if
a 50 percent credit has already been taken for volatilization of ammonia
in liquid sludge, this additional credit is not appropriate. If no
credits are taken for volatilization or other gaseous losses, it would
be conservative to assume that 10 percent of the inorganic N in sludges
is lost during the application year in forested systems.
7.3.3 Cumulative Metal Loadings
7.3.3.1 General
The interaction of metals in sludge with soils is discussed in Appendix
B. Generally, metals in sludge are considered less a potential problem
in sjudge application to forest lands than in application to agricul-
tural crops, because forest vegetation is .not part of the human food
chain. For proposed forest land applications, it may be possible to ob-
tain regulatory waivers of annual metals limits.
7.3.3.2 Calculation of Cumulative Metal Loadings
For very conservative designs, it is suggested that cumulative metal
loadings to forest lands adhere to the same Criteria stipulated in Chap-
ter 6 for agricultural lands. These limits are shown in Table 6-2.
However, for forest application, the stipulation in Table 6-2 that the
soil must be maintained at pH 6.5 or above should be waived. The Cd
limit need not be applied to forest lands since food chain crops would
not be grown, and Cd toxicity to forest vegetation is not a serious con-
cern. Note that Table 6-2 relates the metal loading limits to soil
cation exchange capacity (CEC). For forest application, the .designs will
generally use the middle column of Table 6-2 (applicable to soil CEC of
5 to 15 meq/100 g), as repeated below.
7-8
-------
Metal
Pb
Zn
Cu
Ni
Maximum Cumulative
Loading (kg/ha)
1,120
560
280
280
There was insufficient data available at the time that this manual was
prepared to determine limits of metal phytotoxicity for various tree
species, although research does indicate that limits can be more liberal
than for agricultural crops. Based on agricultural crop limits, it is
probable that the cumulative metal limits can be exceeded for most tree
species without creating phytotoxic conditions.
7.4 Effect of Sludge Additions on Tree Growth and Wood Properties
Accelerated tree growth (200 to 300 percent) resulting from sludge addi-
tion has the potential for changing basic wood characteristics, includ-
ing specific gravity, shrinkage, fibril angle, and certain mechanical
properties. Research to date indicates that both positive and negative
effects on wood quality occur in trees grown on sludge-amended soil.
The static bending tests which show the combined effects have shown no
significant change when the strength properties of specimens cut from
trees grown on sludge-amended soils were compared with specimens of wood
produced without sludge.
7.5 Comparison of
of Growth
Sludge Application to Forest Land in Various Stages
The designer may have the
sludge addition which are:
option of selecting forest land sites for
t Recently cleared prior to replanting.
Young plantations in the range of 2 to 5 years old.
.7- t Established forests.
There are advantages and disadvantages to be considered in each type of
forest site. These are summarized in Tables 7-3 to 7-5.
7-9
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TABLE 7-3
SLUDGE APPLICATION TO RECENTLY CLEARED FOREST SITES
Advantages
1. Better access for sludge application equipment. Also, optimal access
can be established for additional sludge application in the future.
2. Possible option of incorporating the sludge into the soil (versus a
surface application) if the site is sufficiently cleared.
3. Possible option of establishing ridge and furrow, or flooding sludge
application system (versus spray application) if the site topography is
favorable.
4. Option to select tree species which show good growth and survival char-
acteristics on sludge amended sites.
5. Often easier to control public access to the site because cleared areas
are less attractive than wooded areas for typical forest recreational
activities.
Disadvantages
1. Seedlings of some tree species show poor survival when planted directly
in freshly applied sludge. It may be necessary to let the sludge age
for 6 months or more, to allow salt leaching, ammonia volatilization,
etc. However, deciduous species and many conifers, including Douglas
fir and Sitka spruce, have shown excellent tolerance to sludge in
demonstration projects.
2. Seedlings have low nitrogen uptake rates. If nitrate contamination of
an underlying potable aquifer is a potential problem, initial sludge
applications must be small relative to the volume of sludge application
to established forests.
3. An intensive program of weed control is necessary since the weeds grow
faster than the seedlings, and compete for nutrients, space, light,
etc. Use of herbicides and cultivation between tree rows is usually
required for the first 3 to 4 years.
4. Intensive browsing by deer and damage to young trees by voles and other
pest species may require special control measures, since these animals
may selectively feed upon trees grown on sludge-amended sites due to
their higher food value.
7-10
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TABLE 7-4
SLUDGE APPLICATION TO YOUNG FOREST PLANTATIONS (OVER 2 YEARS OLD)
Advantages
1. Seedlings are established and more tolerant of fresh sludge applica-
tions.
2. Weed control is less of a problem than with cleared sites because of
established trees and vegetation.
3. Nitrogen uptake by the trees is rapidly increasing and acceptable
sludge application rates can be higher on sites over sensitive aqui-
fers.
4. Access for sludge application equipment is usually still good.
5. Rapid growth response from most deciduous and many coniferous tree
seedlings can be expected.
Disadvantages
1. Sludge application by spraying over the canopy may be restricted to
those periods when the trees are dormant, to avoid the problem of
sludge clinging to foliage. If application can be planned shortly
before heavy rainfall, this problem can be circumvented by the washing
effect of the rain.
2. Some weed control will still probably be necessary.
3. Plant nitrogen uptake rate is less than that of a well-established
forest cover.
7-11
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TABLE 7-5
SLUDGE APPLICATION TO CLOSED ESTABLISHED FORESTS
(OVER 10 YEARS OLD)
Advantages
1. Established forest land is often more readily available in sufficient
area (size) and closer distance to sewage treatment plants than cleared
sites or young plantations.
2. Established forests are less susceptible to sludge-induced changes in
vegetation (e.g., weed growth).
3. Plant nitrogen uptake is higher, allowing more sludge to be applied
without exceeding nitrogen limits necessary to prevent nitrate leaching
to sensitive aquifers.
4. Excellent growth response can be expected to result from the increased
nutrients. This is not true of old trees, however. What 1s "old"
varies between species, but generally lies between 30 and 60 years.
5. Sludge application by spraying can be done under the tree foliage, so
it is not necessary for the trees to be dormant.
6. During precipitation, rapid runoff of storm water containing sludge
constituents is unlikely, because the forest canopy breaks up the rain,
and accumulated organic debris on the forest floor absorbs runoff,
7. Forest soils under established forests usually have high C-to-N ratios
resulting in excellent capability to immobilize (store) nitrogen for
slow release in future years. Consequently, it is often feasible to
make an initial heavy application of sludge, e.g., 60 kg/ha (54 T/ac),
and achieve excellent tree growth response for up to 5 years without
subsequent sludge applications.
Disadvantages
1.
2.
3.
Access by sludge application vehicles into a mature forest is often
difficult. The maximum range of sludge spray cannons is about 40 m
(120 ft). To obtain fairly uniform coverage, the spray application
vehicle requires access into the site on a road grid, spaced at approx-
imately 75-m (250-ft) intervals. Most established forest sites are not
provided with grid-like roads. As a result, access roads must be cut
through the forest, or the selected sludge application area(s) are
largely 'restricted to narrow 36-m (120-ft) strips on both sides of
existing roads. Access into commercial forests is usually easier than
into publicly owned forest lands.
Control of public access is usually more difficult in an established
forest. If the sludge is applied to narrow strips adjacent to existing
roads, the potential problem may be of more concern. Again, use of
commercial forest may mitigate the control of public access.
In an established publicly owned forest, it may not be advantageous to
accelerate vegetation growth with sludge applications. In contrast,
commercial forest operations desire faster growth of trees.
7-12
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7.6 Design Example of Sludge Application to Forested Lands
Part of this design example is developed to demonstrate the procedures
needed to ensure protection of drinking water aquifers during an annual
sludge application program. As a result, the values are very conserva-
tive. In the general case, it is more typical to apply a single, larger
quantity of sludge every 3 to 5 years. The total amount of sludge ap-
plied is based on the nutrient needs of the forest vegetation over the
3- to 5-year period. However, this may result in nitrate migration to
ground water during the first year. If site conditions allow such an
impact to occur, it will usually be more economical to apply a larger
quantity of sludge every.3 to 5 years (see the design example in Chapter
8 for this case). The criteria used for this example are as follows:
Nitrogen application not
plants to utilize the N
losses.
to exceed the ability of the forest
applied with appropriate credit for
2. Cumulative metal loading limits not to exceed those generally
allowed for cropland. The major departure for this case is
that forest soil pH can be lower than the pH 6.5 recommended
for agriculture. In addition, if the site is ever to be con-
verted to food chain agriculture, then the cumulative Cd limits
will also apply. If the site will always remain a forest or be
used for other non-food chain purposes, then Cd limits should
not apply.
7.6.1 Sludge Quantity and Quality Assumptions
The sludge generated by the hypothetical community in this example is
assumed to have the following average characteristics:
Anaerobically digested sludge generated in the average amount
of 18.2 mt/day (20 T/day), dry weight, by an activated sludge
sewage treatment plant.
Liquid sludge averages 4 percent solids by weight; its volume
is 445,600 I/day (117,600 gal/day).
Average sludge analysis on a dry weight basis is:
Organic N 3 percent by weight
NH^N 1 percent by weight
NOg None
Pb 500 mg/kg
Zn 2,000 mg/kg
Cu 500 mg/kg
Ni 100 mg/kg
Cd 50 mg/kg
7-13
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7.6.2. Site Selection
The hypothetical community is located in the Pacific Northwest. A large
commercial forest is located 24 km (15 mi) from the sewage treatment
plant. The grower believes that he can expect a significant increase in
tree growth rate resulting from the nutrients in the sludge. Prelimi-
nary investigations of the grower's property shows that a total of 3,000
ha (7,400 ac) are available, of which 1,200 ha (3,000 ac) have the fol-
lowing desirable characteristics:
Convenient vehicle access from public and private roads, plus
an in-place network of logging roads within the area.
No surface waters used for drinking or recreational purposes
are located within the area. Intermittent stream locations
are mapped, and 90-m (290-ft) (or greater) buffer zones can be
readily established around the stream beds.
Ground water under one portion of the site has the potential
to serve as a drinking water aquifer.
Public access is limited by signs and fences adjacent to pub-
lic roads.
Topography is satisfactory, in that the area consists largely
of slopes less than 6 percent, and slopes steeper than 30 per-
cent can be readily excluded from the sludge application pro-
gram.
There are no residential dwelling units within the area.
The area is roughly equally divided between young plantations
2 to 4 years old and an established forest. However, the
1,200 ha (3,000 ac) contains an area of 200 ha (500 ac), which
contains tree species which have undocumented response to
sludge addition. This area is excluded.
7.6.2.1 Soil and Hydrological Properties of the Site
The soils are of two types: glacial outwash, and residual soil devel-
oped from andesitic bedrock. The glacial outwash is located largely on
terraces with slopes less than 10 percent. Infiltration is rapid. The
soil pH ranges between 5.5 and 6.0, and CEC is 14 meq/100 g. A 2.5- to
5.0-cm (1- to 2-in) litter layer exists in the established forest. The
ground water table is approximately 9 m (30 ft) below the soil surface.
Residual soil is found on slopes ranging up to 40 percent. Slopes
steeper than 30 percent were eliminated from further consideration.
7-14
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7.6.3 Calculate the Sludge Application Rate
Assume that the sludge is to be applied on an annual basis, and that the
quantity of sludge applied is limited by N. The purpose of the calcula-
tion is to have the plant-available N in the applied sludge equal the N
uptake of the trees and understory, plus assumed denitrification losses
discussed in Section 7.3.2.4. This is a conservative approach intended
to prevent leaching of nitrate to the ground water aquifer.
a. Step 1 - Calculate the amount of available N per ton of sludge
applied in the first year. Available Np = (NH4-N) - (1%-N volatil-
ized) + (organic N x % mineralization rate in the first year) -
(losses unaccounted for), all on a dry weight basis.
where:
b.
c NH4-N = 1% by weight = 10'kg/rot (20 Ib/T).
Organic N =3% by weight = 30 kg/rat (60 Ib/T).
NH4-N volatilized = 50% of NH4 in sludge, an assumption for
surface-applied liquid sludge.
Percent organic N mineralized = 20% in the first year, an as-
sumption (see Table 6-7).
t Percent of losses unaccounted for is assumed to be zero for
surface-applied liquid sludge, for which we have already sub-
tracted 50 percent of the NH4-N during application.
Available N in first year = 10 - (10 x 0.5) + (30 x 0.2) = 11
kg/mt (22 Ib/T) of applied sludge.
Step 2 - Calculate the amount of available N per ton of sludge ap-
plied in succeeding years, including the effect of organic N mineral-
ization from previous years' sludge applications. Available N =
(NH4-N) - (NH4-N volatilized) + (organic N x % mineralization rate in
first year) - (losses unaccounted for) + (organic N applied in previ-
ous years x % mineralization rate for previous years), all on a dry
weight basis.
where:
Assumed organic N mineralization rates from previous years' sludge
applications are taken from Table 6-7, as follows:
Year
0-1
1-2
2-3
3-4
4-5
Rate
0.20
0.10
0.05
0.03
0.03
7-15
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First Year
Np = 11 kg/mt (22 Ib/T) of sludge applied. See Step 1 calculation.
Second Year
Np * 11 + (30 x 0.1) = 14 kg/mt (28 Ib/T) of sludge applied
Third Year
Np = 11 + (30 x 0.1) + (30 x 0.05) = 15.5 kg/mt (31 Ib/T) of sludge
applied.
Fourth Year
Np = 11 + (30 x 0.1) + (30 x 0.05) + (30 x 0.03) = 16.4 kg/mt (32.8
Ib/T) of sludge applied.
Fifth Year
NQ = 11 + (30 x 0.1) + (30 x 0.05) + (30 x 0.03) + (30 x 0.03) =
17.3 kg/mt (34.4 Ib/T) of sludge applied.
c. Step 3 - Calculate the annual quantity of sludge which can be ap-
plied to the established forest portion of the sludge application
site. Assume that the plant uptake of N for the established forest
remains constant at 168 kg/ha (150 Ib/ac) each year.
First Year - Established Forest
Sludge application rate =
= 15.3 mt/ha (6.8 T/ac)
Second Year - Established Forest
Sludge application rate =
168
= 12 mt/ha (5.4 T/ac)
Third Year - Established Forest
Sludge application rate =
168
= 10.8 mt/ha (4.8 T/ac)
Fourth Year - Established Forest
168
Sludge application rate = j"". = 10.2 mt/ha (4.6 T/ac)
7-16
-------
Fifth Year - Established Forest
Sludge application rate =
168
= 9.7 mt/ha (4.3 T/ac)
d. Step 4 - Calculate the annual quantity of sludge which can be ap-
plied to the young plantation portion of the sludge application
site. Assume that the plant N uptake for the young plantation in-
creases each year during the 5 years because of tree growth, in the
following manner:
Year
0-1
1-2
2-3
3-4
4-5
Young Plantation Plant N
Uptake (kg/ha)
20
30
45
65
90
First Year - Young Plantation
20
Sludge application rate = -^ = 1.8 mt/ha (0.8 T/ac)
Second Year - Young Plantation
30
Sludge application rate = r = 2.1 mt/ha (1.0 T/ac)
Third Year - Young Plantation
45
Sludge application rate = * K = 2.9 mt/ha (1.3 T/ac)
xO» 0
Fourth Year - Young Plantation
Sludge application rate =
65
= 4.0 mt/ha (1.8 T/ac)
Fifth Year - Young Plantation
90
Sludge application rate = -^ ~ = 5.2 mt/ha (2.3 T/ac)
1 / » O
7-17
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e. Step 5 - Summarize the sludge application rate calculations, as fol-
lows:
Year
0-1
1-2
2-3
3-4
4-5
Established Forest
(mt/ha)
15.3
12.0
10.8
10.2
9.7
Young Plantation
(mt/ha)
1.8
2.1
2.9
4.0
5.2
7.6.4 Calculate the Quantity of Sludge Which Can Be Applied to
the Site
The site has 1,000 ha (2,471 ac) suitable for sludge application, which
is roughly equally divided between established forest and young planta-
tion (assume 500 ha [1,235 ac] of each). The quantity of sludge which
can be applied is summarized below:
Established Forest
Year (mt)
0-1 7,650
1-2 6,000
2-3 5,400
3-4 5,100
4-5 4,850
Young Plantation
(mt)
900 8,550
1,050 7,050
1,450 6,850
2,000 7,100
2,600 7,450
The community generates 18.2 mt/day (20 T/day), dry weight, of sludge,
or 6,643 mt/year (7,307 T/year), so the hypothetical site is of suffi-
cient area. If possible, the portion of the site area overlying the
drinking water aquifer should be excluded so that the final design would
not be constrained by nitrate limits. If that is not possible, then the
final design should include an allowance for permissible nitrate concen-
trations (10 mg/1) at the project boundary, and raise the sludge load-
ings accordingly. The preliminary calculations above do not include
this allowance.
7.6.5 Determine Cumulative Metals Loadings
Metal
Pb
In
Cu
Ni
kg/mt Sludge
0.5
2.0
0.5
0.1
Limits (kg/ha)
(Table 6-2)
. 1,120
560
280
280
7-18
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7.6.6 Cumulative Sludge Loadings
ExamPle: Pb -
= 2'24° mt/ha
Metal
Pb
Zn
Cu
Ni
rot Sludge/ha
2,240
280
560
2,800
Since it is a commercial forest, and there is no intention to convert to
food chain crop production, the Cd limit does not apply. The Zn limit
of 280 mt is adopted as a conservative control. The phytotoxic effects
are not well known, but it seems likely that the forest vegetation could
accept much higher levels without harm.
At 280 mt/ha, the useful design life of the sites is as follows:
Established Forest:
New Plantation:
280 mt/ha _
11 mt/yr ~
yr
280
= 56 yr
7.6.7 Application Scheduling
Scheduling sludge application requires a consideration of both the soil
and age of the forest. High rainfall periods and/or freezing conditions
can limit sludge applications in almost all situations. Vehicle access
to the steeper soils could potentially be too difficult during the wet
parts of the year. All applications to the young plantations will be
done during the late fall, winter, and early spring when the trees are
dormant. An application schedule for a 1-year period is shown in the
Table 7-6 for this design example.
It would be feasible with the schedule in Table 7-6 to avoid any need
for storage. However, because adverse climatic conditions cannot be
predicted, ,it is recommended that a 1-month (30-day) storage lagoon be
constructed. Such a.lagoon would hold approximately 550 dry mt (600 T).
At 4 percent solids, the liquid storage capacity required would be 13.3
mil 1 (3.4 mil gal).
7.6.8 Sludge Application Equipment
In 1982, the City of
Washington) developed
Seattle (Municipality of Metropolitan Seattle,
specifications for, and procurred, a specially
7-19
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equipped and modified sludge application vehicle for forest sludge ap-
plications (63), as shown in Figure 7-1. The vehicle is articulated,
four-wheel drive, and capable of traversing a 25 percent side slope and
tight turn radii. Maximum vehicle width is 2.74 m (9 ft), since 3.05-m
(10-ft) tree spacings are common on timber plantations. Additional spe-
cial equipment includes a 7,570-1 (2,000-gal) sludge tank, a sludge can-
non able to project 757 1 (200 gpm) of sludge a minimum distance of 30 m
(100 ft), flotation tires, and a lightweight dozer blade and winch to
move stumps, fallen trees, and other obstacles which might be encoun-
tered. Vehicle cost in early 1983 was $175,000. It is assumed that ve-
hicles similar to this would be used for the hypothetical design exam-
ple.
7.7 References
1. Allaway, W. H. Agronomic Controls Over the Environmental Cycling
of Trace Elements. Adv. Agron., 20:235-274, 1968.
2.
3.
4.
5.
Anderson, D. A. Response of the Columbian Black-Tailed Deer to
Fertilization of Douglas-Fir Forests with Municipal Sewage Sludge.
Ph.D. Dissertation, University of Washington, Washington, 1981.
Antonovics, J. Metal Tolerance in Plants: Perfecting an Evolu-
tionary Paradigm. In: International Conference on Heavy Metals in
the Environment, Toronto, Canada, 1975. Vol. 2, Pt. 1. pp. 169-
185.
Archie, S. G., and M. Wilbert. Management of Sludge-Treated Plan-
tations. In: Municipal Sludge Application to Pacific Northwest
Forest Land. C. S. Bledsoe, ed. Contribution No. 41, Institute of
Forest Resources, University of Washington, 1981. 155 pp.
Bagdasaryan, 6. A. Survival of Viruses of the
(Poliomyelitis, Echo, Coxsackie) in Soil and on
Epidemiol. Microbiol. Immunol.
Enterovirus Group
Vegetation. Hyg.
6. Berry, C. R. Initial Response of Pine Seedlings and Weeds to Dried
Sewage Sludge in Rehabilitation of an Eroded Forest Site. Research
Note SE-249, U.S. Forest Service, Washington, D.C. 1977.
7. Bledsoe, C. S. Composted Sludge as a Plant Growth Medium. In:
Municipal Sludge Application to Pacific Northwest Forest Land. C.
S. Bledsoe, ed. Contribution No. 41, Institute of Forest Re-
sources, University of Washington, Seattle, 1981.
8. Bledsoe, C. S., and R. J. Zasoski. Seedling Physiology of Eight
Tree Species Grown in Sludge-Amended Soils. In: Municipal Sludge
Application to Pacific Northwest Forest Lands. C. S. Bledsoe, ed.
Contribution No. 41, Institute of Forest Resources, University of
Washington, Seattle, 1981. pp. 93-100.
7-20
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TABLE 7-6
MONTHLY APPLICATION SCHEDULE FOR A DESIGN
IN THE PACIFIC NORTHWEST*
Glacial Soil
Residual Soil
Month
January
February
March
April
May
June
July
August
September
October
November
December
Young
Plantation
A
A
A
NA
NA
NA
NA
NA
NA
A
A
A
Established
Forest
A
A
A
A
A
A
A
A
A
A
A
A
Young
Plantation
LA
LA
LA
NA
NA
NA
NA
NA
NA
LA
LA .
LA
Established
Forest
.LA
LA
LA
A
A
A
A
A
A
LA
LA
LA
Abbreviations:
A = Site available, no limitations.
NA = Not available, damage will be caused by sludge on growing
foliage.
LA = Limited availability, periods of extended rain are to be avoided due to
vehicle access problems.
Figure 7-1
Forest land sludge application vehicle (courtesy
of City of Seattle).
7-21
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9. Britton, 6.
York, 1980.
14.
15.
16.
Introduction to Environmental
326 pp.
Virology. Wiley, New
10. Britton, G., B. Damron, G. T. Edds, and J. M. Davidson. Sludge-
Health Risks of Land Application. Ann Arbor Science, Ann Arbor,
Michigan, 1980. 367 pp.
11. Breuer, D. W., D. W. Cole, and P. Schiess. Nitrogen Transformation
and Leaching Associated with Wastewater Irrigation in Dpuglas-Fir,
Poplar, Grass, and Unvegetated Systems. In: Utilization of Muni-
cipal Sewage Effluent and Sludge on Forest and Disturbed Land. W.
E. Sopper and S. N. Kerr, eds. Pennsylvania State University
Press, University Park, 1979. pp. 19-34.
12. Brockway, D. G. Evaluation of Northern Pine Plantations as Dis-
posal Sites for Municipal and Industrial Sewage Sludge. Ph.D.
Thesis, Michigan State University, 1979.
13. Chaney, R. L., M. C. White, and P. W. Simon. Plant Uptake of Heavy
Metals from Sewage Sludge Applied to Land. In: Proceedings, 2nd
National Conference on Municipal Sludge Management and Disposal,
Washington, D.C., 1975. pp. 169-178.
Chaney, R. L. Health Risks Associated with Toxic Metals in Muni-
cipal Sludge. In: Sludge-Health Risks of Land Application. G.
Britton, B. L. Damron, G. T. Edds, and J. M. Davidson, eds. Ann
Arbor Science, Ann Arbor, Michigan, 1980. pp. 59-83.
Chaney, R. L., and P. M. Giordano
Plant Deficiencies and Toxicities.
Organic Wastes and Wastewaters. L.
eds. American Society of Agronomy,
235-279.
Microelements as Related to
In: Soils for Management of
F. Elliott and F. J. Stevenson,
Madison, Wisconsin, 1977. pp.
Chaney, R. L., and C. A. Lloyd. Adherence
Digested Sewage Sludge to Tall Fescue. J.
411, 1979.
of Spray-Applied
Environ. Qual
Liquid
., 8:407-
17. Chaney, R. L., P. T. Hundemann, W. T. Palmer, R. J. Small, M. C.
White, and A. M. Decker. Plant Accumulation of Heavy Metals and
Phytotoxicity Resulting from Utilization of Sewage Sludge and
Sludge Composts on Cropland. In: Proceedings, 1977 National Con-
ference on Composting of Municipal Residues and Sludges, Washing-
ton, D.C., 1977. pp. 86-97.
18. Christenson, T. H. Cadmium Sorption onto Two Mineral Soils. Ph.D.
Thesis, University of Washington, 1980.
19. Clark, D. R., Jr. Lead Concentration: Bats Versus Terrestrial
Small Mammals Collected Near a Major Highway. Environ. Sci. Tech.,
13:338-341, 1979.
7-22
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20. Cole, D. W. Response of Forest Ecosystems to Sludge and Wastewater
Applications - A Case Study in Western Washington. In: Land Rec-
lamation and Biomass Production with Municipal Wastewater and
Sludge. W. E. Sopper, E. M. Seaker, and R. K. Bastian, eds. Penn-
sylvania State University Press, University Park, 1982. pp. 274-
291.
21. Cole, D. W., and P. Schiess. Renovation of Wastewater and Response
of Forest Ecosystems: The Pack Forest Study. In: State of Knowl-
edge in Land Treatment of Wastewater. H. L. McKim, ed. 'U.S. Army
Corps of Engineers Cold Region Research Engineering Laboratory,
Hanover, New Hampshire, 1978. pp. 323-331.
22,
23.
24.
25.
26.
27.
28.
29.
Cole, D. W., W. I. B. Crane, and C. C. Grier. Effects of Forest
Management Practices on Water Chemistry in a Second-Growth Douglas-
Fir Ecosystem. In: Forest Soils and Forest Land Management. B.
Bernier and C. H. Winget, eds. Presses de TUniversite Laval, Que-
bec, 1975. pp. 195-207.
Cooley, J. H. Applying Liquid Sludge to Forest Land: A Demonstra-
tion. Presented at Fifth Annual Madison Conference of Applied Re-
search and Practice on Municipal and Industrial Waste. University
of Wisconsin, Madison, Wisconsin, September 22-24, 1982.
Corey, J. G., G. J. Hollod, V. M. Stone, C. G. Wells, W. H. McKee,
and S. M. Bartell. Environmental Effects of Utilization of Sewage
Sludge for Biomass Production. In: Land Reclamation and Biomass
Production with Municipal Wastewater and Sludge. W. E. Sopper, E.
M. Seaker, and R. K. Bastian, eds. Pennsylvania State University
Press, University Park, 1982. pp. 265-273.
Council for Agricultural Science and Technology. Effects of Sewage
Sludge on the Cadmium and Zinc Content of Crops. EPA 600/18-081-
003, Ames, Iowa, February 1981. 91 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB81 181596)
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Chaney, and T. S. Rumsey. Animal Performance on Pastures Top-
dressed with Liquid Sewage Sludge and Sludge Compost. In: Na-
tional Conference on Municipal and Industrial Sludge Utilization
and Disposal, Washington, D.C., May 1980. pp. 37-41.
Doyle, J. J. Effects of Low Levels of Dietary Cadmium in Animals -
A Review. J. Environ. Qual . , 6:111-116, 1977.
Drewry, W. A., and R. Eliassen. Virus Movement
Water Poll. Control Fed., 40:257-271, 1968.
in Groundwater. J.
Edmonds, R. L. Survival of Coliform Bacteria in
plied to a Forest Clearcut and Potential Movement
Appl. Environ. Microbiol., 32:537-546, 1976.
Sewage Sludge Ap-
into Groundwater.
7-23
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30. Edmonds, R. L. Microbiological Characteristics of Dewatered Sludge
Following Application to Forest Soils and Clearcut Areas. In:
Utilization of Municipal Sewage Effluent and Sludge on Forest and
Disturbed Land. W. E. Sopper and S. N. Kerr, eds. Pennsylvania
State University Press, University Park, 1979. pp. 123-136.
31. Edmonds, R. L., and D. W. Cole. Use of Dewatered Sludge as an
Amendment for Forest Growth: Management and Biological Assessment.
Vol. I. Center for Ecosystem Studies, University of Washington,
Seattle, Washington, 1976.
32. Edmonds, R. L., and D. W. Cole. Use of Dewatered Sludge as an
Amendment for Forest Growth: Management and Biological Assessment.
Vol. II. Center for Ecosystem Studies, College of Forest Re-
sources, University of Washington, Seattle, Washington, 1977.
33. Edmonds, R. L., and D. W. Cole. Use of Dewatered Sludge as an
Amendment for Forest Growth: Management and Biological Assessment.
Vol. III. Center for Ecosystem Studies, College of Forest Re-
sources, University of Washington, Seattle, Washington, 1980.
34. Edmonds, R. L., and W. Littke. Coliform Aerosols Generated from
the Surface of Dewatered Sewage Applied to a Forest Clearcut.
Appl. Environ. Microbiol.,, 36:972-974, 1978.
35. Edmonds, R. L., and K. P. Mayer. Survival of Sludge-Associated
Pathogens and Their Movement into Ground Water. In: Municipal
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36. Ernst, W. H. 0. Physiology of Heavy Metal Resistance in Plants.
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37. Fox, M. R. S. Effect of Essential Minerals on Cadmium Toxicity; a
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Levels Similar to Those in Man. Environ. Health Perspect., 28:107-
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39. Garba, C. P., C. Wallis, J. L. Melnick. Fate of Wastewater Bac-
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174, 1975.
40. Garcia-Maragaya, J., and A. L. Page. Sorption of Trace Quantities
of Cadmium by Soils with Different Chemical and Mineralogical Com-
position. Water, Air, Soil Pollut., 9:289-299, 1979.
7-24
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41. Haschek, W. M., D. L. Lisk, and R. A. Stehn. Accumulations of Lead
in Rodents from Two Old Orchard Sites in New York. In: Animals as
Monitors of Environmental Pollutants. National Academy of Sci-
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42. Healy, W. B., P. C. Rankin, and H. M. Watts. Effect of Soil Con-
tamination on the1 Element Composition of Herbage. N. Z. J. Agr.
Res., 17:59-61, 1974.
43. Helmke, P. A., W. P. Robarge, R. L. Korotev, and P. J. Schomberg.
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in Earthworms. J. Environ. Qual. 8:322-327, 1979.
44. Jacobs, R. M., A. 0. Lee Jones, M. R. Spiney Fox, and B. E. Fry,
Jr. Retention of Dietary Cadmium and the Ameliorative Effect of
Zinc, Copper, and Manganese in Japanese Quail. J. Nutr., 108:22-
32, 1978.
45. Jones, S. C., K. W. Brown,. L., E. Deuel, and K. C. Donnelly. Influ-
ence of Rainfall on the Retention of Sludge Heavy Metals by the
Leaves of Forage Crops. J. Environ. Qual., 8:69-72, 1979.
46. Kelley, J. M., G. R. Parker, and W. W. McFee. Heavy Metal Accumu-
lation and Growth of Seedlings of Five Forest Species as Influenced
by Soil Cadmium Levels. J. Environ. Qual., 8:361-364, 1979.
47. Kittrick, J. A. Control of Zn+2 in Soil Solution by Sphalerite.
Soil Sci. Soc. Amer. J., 40;314-317, 1976.
48. Korcak, R. F., F. R. Gouin, and D. S. Fanning. Metal Content of
Plants and Soil in .a Tree Nursery Treated with Composted Sludge.
J. Environ. Qua!., 8:63-68, 1979.
49. Koterba, M. T., J. W. Hornbeck, and R. S. Pierce. Effects of
Sludge Application on Soil . Water Solution and Vegetation in a
Northern Hardwood Stand. J. Environ. Qua!., 8:72-78.
50. Kreuz, A. Hygienic Evaluation of the Agricultural Utilization of
Sewage, Gesundheitsung, 76:206-215, 1955.
51. Kuo, S., and A. S. Baker. Sorption of Copper, Zinc, and Cadmium by
Some Acid Soils. Soil Sci. Soc. Am. J., 44:969-974, 1980.
52. Lambert, D. H., and C. Weidensaul. Use of Sewage Sludge for Tree
Seedling and Christmas Tree Production. In: Land Reclamation and
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Sopper, E. M. Seaker, and R. K. Bastian, eds.' Pennsylvania State
University Press, University Park, 1982. pp. 292-300.
7-25
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53. Lamorex, R. J., and W. R. Chaney. Growth and Water Movement in
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6:201-204, 1977.
54. Levine, P. F. Sorption of Zinc, Lead, and Cadmium on a Glacial
Outwash Soil. 'M.S. Thesis, University of Washington, 1975.
55. Lisk, D. J. Trace Metals in Soils, Plants, and Animals. Adv.
Agron., 24:267-325, 1972.
56. Mallmann, W. L., and W. Litsky. Survival of Selected Enteric Or-
ganisms in Various Types of Soil. Am. J. Publ. Health, 41:38-44,
1951.
57. Mayer, K. P. Decomposition of Dewatered Sewage Sludge Applied to a
Forest Soil. M.S. Thesis, University of Washington, 1980.
58. Mayland, H. F., G. E. Shewmaker, and R. C. Bull. Soil Ingestion by
Cattle Grazing Crested Wheatgrass. J. Range Mgmt., 30:264-265,
1977.
59. McCormick, L. H., and K. C. Steiner. Variation in Aluminum Toler-
ance Among Six Genera of Trees. Forest Sci., 24:565-568, 1978.
60. McKim, H. L., W. E. Sopper, D. Cole, W. Nutter, D. Urie, P.
Schiess, S. N. Ker'r, and H. Farqubar. Wastewater Application in
Forest Ecosystems. CRREL Report 119, U.S. Army Cold Regions Re-
search Engineering 'Laboratory, Hanover, New Hampshire, May 1980.
29 pp.
61. Mineral Tolerance of Domestic Animals. National Academy of Sci-
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62. Munshower, F. F., and D. R. Neuman. Metals in Soft Tissues of Mule
Deer and Antelope. Bull. Environ. Contam. Toxicol., 22:827-832,
1979.
63. Nichols, C. Seattle Sludge and Silvaculture. Water Eng. Man.,
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64. Nichols, C. G. Engineering Aspects of Dewatered Sludge Land Appli-
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1980.
65. Page, A. L., A. A. Elseewi, and J. P. Martin. Capacity of Soils
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Orlando, Florida, January 1978. pp. 97-105.
7-26
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Reddy, C. N., and W. H. Patrick, Jr. Effects of Redox
the Stability of Zinc and Copper Chelates in Flooded
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Subalpine and Alpine Soils of New Hampshire. Oikos, 26:264-275,
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CHAPTER 8
PROCESS DESIGN FOR DISTURBED LAND
8.1 GENERAL
This chapter presents design information for application of sewage
sludge to disturbed land. It is assumed that the preliminary planning
discussed in earlier chapters has been done, that a sludge transporta-
tion system has been selected, and that disturbed lands are potentially
available within a reasonable distance from the POTW. Primary emphasis
is upon the revegetation of the disturbed land site with grasses and/or
trees. If future land use for agricultural production is planned, the
reader should also refer to Chapter 6, "Process Design for Agricltural
Utilization."
Disturbed land can result from both surface and underground mining oper-
ations, as well as the deposition of ore processing wastes. The Soil
Conservation Service reported that as of July 1, 1977, the minerals in-
dustry had disturbed a total of 2.3 mil ha (5.7 mil ac), of which about
50 percent was associated with surface mining (65). Only about one-
third of the disturbed area is reported to have been reclaimed.
Extensive areas of disturbed land exist throughout the United States.
As a result of mining for clay, gravel, sand, stone, phosphate, coal,
and other minerals. Also fairly widespread are areas where dredge
spoils or fly ash have been deposited, and construction areas (e.g.,
roadway cuts, borrow pits) (55).
Most disturbed lands are difficult to revegetate. These sites generally
provide a harsh environment for seed germination and subsequent plant
growth. Major soil problems may include a lack of nutrients and organic
matter, low pH, low water-holding capacity, low rates of water infiltra-
tion and permeability, poor physical properties, and the presence of
toxic levels of trace metals. To correct these conditions, large appli-
cations of lime and fertilizer may be required, and organic soil amend-
ments and/or mulches also may be necessary.
Pilot- and full-scale demonstration projects have shown that properly
managed sludge application is a feasible method of reclaiming disturbed
land, and can provide a cost effective option for municipal sludge dis-
posal. Table 8-1 lists selected projects.
The sludge application is usually a one-time application, i.e., sludge
is not again applied to the same land area at periodic intervals in the
future. Where this is true, the project must have a continuous supply"
of new disturbed land upon which to apply sludge in future years. This
additionaldisturbed land can be created by ongoing mining or mineral
processing operations, or may consist of presently existing large areas
of disturbed land which are gradually reclaimed. In either case, an
8-1
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TABLE 8-1 . - .
SELECTED LAND RECLAMATION PROJECTS INVOLVING MUNICIPAL SLUDGES
State
Pennsylvania
Virginia
West Virginia
Ohio
Maryland
Kentucky
Delaware
Tennessee/
South Carolina
Alabama
Florida
Illinois
26,
49,
Michigan
Wisconsin
Colorado
Oklahoma
Type of
Disturbed Land
Acidic strip-
mine and deep
mine refuse
Acidic strip-
mine spoil
Acidic strip-
mine spoil
Acidic strip-
mine spoil
Acidic strip-
mine spoil and
gravel spoils
Acidic strip-
mine spoils
Dredge spoils
Copper mine,
borrow pit,
kaolin spoil
marginal land
Stripmine
spoils
Phosphate
mining
spoils
Both acidic
and calcareous
stripmine
spoil ; coal
refuse
Quarry spoils
Iron ore trail -
ings; tacom'te
tailings
Molybdenum mine
spoils and coal
mine spoils
Zn smelter out-
fall area
Type of
Vegetation Used
Various grasses,
legumes, and
tree species
Virginia pine
and grasses
and legumes
Blueberries
and tall fescue
Tall fescue and
forage
Grass, legumes,
and row crops
Various tree
species and
row crops
Various grasses
Loblolly pine
and other tree
species; grasses
Various grasses
Various grasses
Various grasses,
legumes, and
tree- species;
forage, row
crops, and small
grains
Various grasses
and tree species
Native prairie
grasses and
forbes; various
grasses and
legumes
Grasses and
native vegeta-
tion
Various grasses
and legume
Type of
Sludge Used References
D1g-D,L,C 24, 31, 32, 33, 38, 54,
55, 56
Dig-D 24, 27, 51, 67
C
Dig-D, C 37, 64
D
Dig-D 23, 67
D
Dig-C 22, 28
C
Oig-D 17, 52
Dig-D
Dig-D 6, 12
Dig-D
Dig-D
Dig-D, L 8, 9, 18, 19, 21, 25,
D 29, 30, 35, 36, 45, 46,
50, 57, 58, 59, 62, 66
D
Dig-D 10, 40
Dig-D
Dig-L 20
8-2
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TABLE 8-1 (continued)
State
Montana
New Mexico
Type of
Disturbed Land
Surface mine
spoils
Coal mine
spoils
Type of Type of
Vegetation Used Sludge Used
Various grasses C
and native vege-
tation
Various grasses Dig-0
References
California
Washington
Clear cut
forest and
construction
areas
Strip mine
spoils, con-
struction
areas and
clear cut
forest
Various grasses Oig-D,C
and tree species
Various tree
species cind
grasses
Dig-D
7, 11, 15
Dig = Digested
L = Liquid
D = Dewatered
C = Composted
8-3
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arrangement is necessary with the land owner to allow for future sludge
application throughout the life of the sludge application project.
8.2 Public Participation Considerations
Public participation aspects are discussed in Chapter 3.
8.3 Post Sludge Application Land Utilization
If sludges are used in the reclamation process there are two sets of
guidelines and recommendations that should be considered. First there
are federal and state mining regulations concerning revegetation under
the Federal Surface Mining Control and Reclamation Act of 1977 (PL 95-
87) (44, 60). Secondly, there are the federal and state guidelines and
recommendations related to land application of sludge. Prior to begin-
ning a reclamation project, the final use of the site after it has been
reclaimed must be considered in relation to compliance with these regu-
lations.
8.3.1 Mining Regulations
Prior to mining, a plan must be submitted to the appropriate agency
stating the method of reclamation and post-mining land utilization.
Under these regulations, the potential post-mining land use must be of a
level equal to or higher than the pre-mining land use. From a mining
engineer's point of view, there are five general levels of involvement
for post-mining land use. They are in increasing order of beneficial
use:
1. Wilderness or unimproved use.
2. Limited agriculture or recreation with little development, such
as forest!and, grazing, hunting, and fishing.
3. Developed agriculture or recreation, such as crop land, water
sports, and vacation resorts.
4. Suburban dwellings or light commercial and industry.
5. Urban dwelling or heavy commercial and industry.
Many of these land uses are compatible with sludge application.
The post-mining use of the site must be considered when determining the
sludge application rate. If the post-mining land use is to be agricul-
tural production or animal grazing, agricultural sludge utilization
practices and restrictions should be considered. If the site is to be
vegetated primarily for erosion control, a single large application of
sludge is desirable for rapid establishment of the vegetative cover. A
majority of the reclaimed mine areas in the humid regions have been
8-4
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planted to forests, some of which are managed for lumber or pulp produc-
tion, while others are allowed to follow natural succession patterns.
If the reclaimed area is to be turned into forestland, larger sludge ap-
plication rates can be considered since the products from the forest are
not generally a factor in the human food chain. In all cases, post-
mining land use must be considered prior to the use of sludge in land
reclamation. . .
8.4 Detailed Site Investigation
Disturbed or marginal land areas differ in their physical, hydrological
and soil chemical characteristics. These differences are the result of
variations in mining operations, ore extraction processes, length of
time since the area was disturbed, climate, soil and geological varia-
tions, and other factors. When the land has been severely disturbed, it
is often necessary to conduct relatively extensive site investigations.
Available soil survey maps, topographic maps, etc. are often useless be-
cause of the changes made to the site's original characteristics.
There may be areas at a disturbed site that, due to physical, hydrologi-
| cals or chemical characteristics, are unsuitable for sludge application.
; Areas suitable for sludge application should be surveyed and boundaries
staked.
Both federal and many state mining regulations in effect in 1982 require
that areas disturbed by mining operations must be restored to the ap-
proximate original contour and productivity (44). However, many older
abandoned mine sites have never been reclaimed. In any case, an accur-
ate topographic contour map of the site area is needed to provide a
basis for (1) delineating the areas with slopes which are too steep for
sludge application, (2) regrading the areas if this expense is cost ef-
fective, and (3) designing surface runoff water improvements, e.g.,
ditches, terraces, berms, etc. Table 5-2 presents general recommenda-
tions for slope limitations. The designer should consult with the ap-
propriate regulatory agencies to determine applicable slope criteria for
the site.
A secondary consideration is the future use of the site. If agricul-
tural use is planned, slopes of less than 6 percent are desirable. If
the area is to be returned to forest and/or native vegetation to prevent
erosion, slopes in excess of 12 percent can be utilized, within applica-
ble regulatory limitations.
8.4.1 Ground Water Protection
The detailed site investigation should determine the following:
Depth to ground water, including seasonal variations.
« Quality of existing ground water.
t Present and potential future use of ground water.
8-5
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Existence of perched water.
Direction of ground water flow.
The general regulatory philosophy is that the application of sludge to a
site should not degrade useful ground water resources beyond the boun-
dary of the sludge application site. Occasionally, it is found that
ground waters adjacent to the disturbed site are already severely de-
graded by previous mining operations and the aquifer can be "exempted"
from non-degradation regulations. Suggested depth to ground water limi-
tations are presented in Table 5-6.
8.4.2 Disturbed Soil Sampling and Analysis
Disturbed soil sampling and analysis are necessary to:
Establish sludge application rates, both periodic and accumu-
lative.
Determine amounts of supplemental fertilizer, lime, or other
soil amendment required to obtain desired vegetative growth.
Determine the infiltration and permeability characteristics
the soil.
of
Determine background soil
to sludge application.
pH, metals, nutrients, etc., prior
A major factor in determining the chemical characteristics of the soil
at a site is that standard soil sampling procedures for undisturbed and
agricultural soil will not be applicable in many cases (see Appendix C).
Soil survey maps will usually only provide an idea of the type of soil
present prior to the disturbance. Often, the only soil profile present
on a surface mined site is the mixture of soil and geologic materials.
A field inspection will have to be made to
cation of samples necessary to characterize
analyses may vary from location to location
regulations covering both the reclamation
pects.
determine the number and lo-
the materials. The specific
based on the state and local
and sludge utilization as-
8.4.2.1 Disturbed Soil Sampling Procedures
Disturbed sites that have had topsoil replaced can often use standard
soil sampling procedures employed on agricultural fields. For abandoned
sites more intensive sampling is often necessary. On either type of
site, because of the extensive soil horizon mixing that occurs during
the removal and replacement of the topsoil and overburden, the surface
material may vary greatly within a small area.
Although the disturbed surface materials are often not soil in the gen-
eric sense, soil tests on disturbed lands have proven useful. However,
soil tests on drastically disturbed sites do have some limitations which
8-6
-------
should be taken into consideration.during site evaluation. Guidelines
vary widely on the number of samples to be taken. Recommendations for
sampling heterogeneous strip mine spoils in the eastern U.S. range from
4 to 25 individual samples per ha (1.5 to 10 per ac). It has also been
suggested that one composite sample made up of a minimum of 10 subsam-
ples for each 4 ha (10 ac) area may be adequate (3). However, many dis-
turbed lands are not heterogeneous, and the range and distribution of
characteristics of the surface material is often more important than/the
average composition. In general, it is recommended that material that
is visibly different in color or composition should be sampled as separ-
ate units (areas) if large enough to be treated separately in the recla-
mation program.
8.4.2.2 Soil pH and Lime Requirements
Most grasses and legumes, along with many shrubs and deciduous trees
grow best in the soil pH range from 5.5 to 7.5, and pH adjustments may
be necessary.
Where sludge is to be applied to land, several states have adopted regu-
lations which state that the soil pH must be adjusted to 6.0 or greater
during the first year of initial sludge application and 6.5 during the
second year (43). In addition, the soil pH of 6.5 must be maintained
for two years after the final sludge application. This is recommended
since trace metals are more soluble under acid conditions than neutral
or alkaline conditions. If the soil pH is not maintained above 6.0, but
is allowed to revert to more acid levels, some trace metals applied in
the sludge may become soluble and once in solution would be available
for plant uptake. In coal spoil banks, iron, aluminum, and manganese
present in the spoil become mobile at low pH's and contribute to acid
mine drainage problems. Phytotoxicity problems may be encountered from
both the trace metals applied in the sludge and native toxic elements
found in the spoil, if the spoil pH becomes highly acid. Liming recom-
mendations can usually be obtained by sending samples to a qualified la-
boratory or the agricultural experiment station soil testing lab at the
nearest land grant college or university. Common soil tests for lime
requirements often seriously underestimate the lime requirement for sul-
fide-containing disturbed lands. In addition, the application of sludge
on disturbed lands will cause further acidification. This must be taken
into consideration in calculating lime requirements.
8.4.2.3 Cation Exchange Capacity (CEC)
Recommended limits related to the CEC of the soil (Table 6-2) have been
developed for the maximum amounts of trace metals that should be applied
to agricultural soils via sewage sludge additives (41). Even though a
particular site will not be returned to agricultural utilization, these
recommendations are often used in state requirements for disturbed land.
Several states have established different limits for maximum amounts of
trace metals that may be applied to the land via sludge based on the CEC
of the soil.
8-7
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8.4.2.4 Disturbed Soil Fertility
During mining and regrading operations, the original surface layers are
usually buried so deeply that the soil nutrients present are not avail-
able to the plants in disturbed soil. Therefore, fertility of the soil
is important in deciding what soil amendments are necessary to establish
vegetation.
Nitrogen and phosphorus are generally deficient on disturbed lands.
Sludge is generally an excellent source "of these nutrients, and recom-
mendations can be obtained from the local agricultural experiment sta-
tion or Cooperative Extension Service for the additional quantity of N,
P, and K required to support the vegetation planned for the site.
Phosphorus is often the most limiting fertility factor in plant estab-
lishment on drastically disturbed land (5). Soil tests used for P anal-
ysis reflect the chemistry of soils, and thus are more regionalized than
tests for other major nutrients. A number of soil tests have been de-
veloped for use on acid soils in the eastern United States and others
for use on neutral and calcareous soils in the west. However, drasti-
cally disturbed lands do hot always reflect the local soils. Thus, if
disturbed spoil material is going to be analyzed for P, the local rou-
tine analysis procedure may not be appropriate and other P analysis
might be required. Recommendations should be obtained from the local
agricultural experiment station.
8.4.3 Chemical Characteristics of Drainage Water
Water pollution problems, such as acid mine drainage, have been associ-
ated with mining activity. Therefore, it is necessary to document the
quality of both the surface and ground water prior to use of sludge on a
disturbed site. In many instances, the water quality on, and adjacent
to, disturbed sites has already been adversely affected.
8.5 Constraints
When designing a sludge utilization project on drastically disturbed
land, there are often two sets of criteria that must be followed. If it
is an active mining site, the project should comply with the criteria
set forth in Public Law 95-87 and any pertinent state regulations (5).
Additionally, if sludge is to be used as a soil amendment, there are
also federal and usually state guidelines and regulations that must be
considered (14, 41, 43).
8.5.1 Constraints Related to Sludge Applications
8.5.1.1 Single Application Versus Annual Application
A major difference between the application of sludge to disturbed land
and the other sludge land application options is that sludge is often"
applied to disturbed land in a one time, single large application, as
compared to annual or periodic smaller applications.
8-8
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Drastically disturbed lands can be divided into two categories, those
requiring topsoil enhancement and those without topsoil. On sites with
topsoil, an agricultural utilization rate might be used with small quan-
tities of sludge being applied annually (discussed in Chapter 6). How-
ever, on abandoned sites or sites without topsoil replacement, a much
larger application of sludge may be necessary in order to establish
vegetation and improve the physical status of the soil. Soil fertility
is also increased by adding sludge nitrogen and phosphorus as well as
many of the micro-nutrients necessary for plant growth., ...
8.5.1.2 Constraints Associated
tics of the Sludge
with the Physical Characteris-
The physical characteristics of sludge are discussed in Chapter 4 and
Appendix A. If liquid sludge is to be applied to mined land, it should
be remembered that in some cases the infiltration rate for disturbed
soils is lower than that for undisturbed soils. The solids in the liq-
uid sludge tend to fill in the surface pores and lower the infiltration
rate. After the surface is clogged, it may be necessary to temporarily
halt sludge application and loosen the surface material. Soils will
also regain permeability when sludge dries. Since liquid sludge can
contain 90 to 99 percent water, the soils hydraulic loading capacity may
often become the limiting factor when determining sludge application
rates. In order to supply an adequate continuous supply of plant nutri-
ents with liquid sludge additional applications may be necessary. Ap-
plication of dewatered, dry, or composted sludge does not pose the po-
tential soil clogging problem discussed above, since there is less water
that has to infiltrate or evaporate.
8.5.2 Pathogens and Parasites
If the disturbed area to be reclaimed is to be used for agricultural
production, then use of agricultural sludge guidelines should be fol-
lowed. If state and federal criteria are met, the system managed prop-
erly, and the sludge treated properly, there should be minimal health
risk associated with agricultural use of the reclaimed areas. See Sec-
tion 6.3.1, and Appendices A and B.
Public access should be restricted for a sufficient period after sludge
application to prevent public contact with viable pathogens. This per-
iod may vary from 30 days to 12 months, depending upon the extent to
which the sludge has been treated for pathogen destruction.
8.5.3 Organics
If the land is to be used for agricultural purposes, see Section 6.3.3
for discussion of constraints pertinent to persistant organics. Persis-
tent organics are generally not a concern providing that the site design
and operation prevents migration of sludge constituents into drinking
water supply sources.
8-9
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8.5.4 Nitrogen
The amount of nitrogen needed to establish vegetation on a disturbed
area is dependent on the type of vegetation to be grown and the amount
of nitrogen available in the soil. The designer should have information
on:
The amount and type of nitrogen in the sludge (organic N, am-
monium, and nitrates).
The plant available nitrogen content of the existing soil, if
available.
The fertilizer nitrogen requirements of the vegetation planned
for the site.
This information is utilized to determine sludge application rate so
that sufficient nitrogen is applied for the vegetation, but not in ex-
cessive amounts that may cause unacceptable levels of nitrate leaching
into the surrounding ground water.
The post reclamation land use should also be considered when determining
the amount of nitrogen needed to supply the vegetative needs. If the
vegetation grown is to be harvested and removed from the site, supple-
mental nitrogen applications may be needed periodically to maintain ade-
quate productivity. If the reclaimed area is reforested or the vegeta-
tion grown is not harvested, most of the nitrogen will remain on the
site and be recycled by means of leaf fall and vegetation decomposition.
An advantage of using sludge is that it is a slow-release organic nitro-
gen fertilizer source that will supply some nitrogen for 3 to 5 years.
Most of the original nitrogen is in the organic form and therefore not
immediately available for plant use until it is converted to available
plant forms by mineralization. This process is discussed in Appendix B.
8.5.5 Total Metal Applications
Metal constraints depend on the future use of the reclaimed land. If the
land is to be used for agricultural crops entering the human food chain
the limits discussed in Section 6.3.4 and 6.3.5 apply to sludge applica-
tion. If, however, the land is to be reforested or planted in vegeta-
tion not entering the human food chain, the metal accumulation is lim-
ited by potential phytoxicity to the trees and vegetation. Copper,
zinc, and nickel are the elements of most concern in plant phytoxicity.
If the soil pH is maintained above 6.0 to 6.5, these elements should not
be taken up by the vegetation in amounts great enough to cause phytoxi-
city.
8-10
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8.6 Vegetation Selection
8.6.1 General
Many species and varieties of plants have been shown to be valuable for
use in the reclamation of drastically disturbed lands. However, each
site should be considered unique, and plant species or seed mixtures to
be used carefully selected. Local authorities should be consulted for
recommendations of appropriate species and varieties of plant materials
and establishment techniques. Revegetation suggestions for various re-
gions of the United States are presented in this section (Tables 8-2
through 8-12). Agricultural food crops are not covered here, since they
were discussed in Chapter 6.
If the aim of the reclamation effort is to establish a vegetative cover
sufficient to prevent erosion, a perennial grass and legume mixture is a
good crop selection. It is important to select species that are not
only compatible, but also grow well when sludge is used as the fertili-
zer. The rationale for the selection of grass and legume seeding mix-
tures is that the grass species will germinate quickly and provide a
complete protective cover during the first year, allowing time for the
legume species to become established and develop into the final vegeta-
tive cover. The grasses will also take up a large amount of the nitro-
gen, preventing it from leaching into the ground water. Since legume
species can fix nitrogen from the atmosphere, additional sludge nitrogen
additions are often unnecessary.
Plant species to be
grow under droughty
alkaline soil
used should be selected because of their ability to
conditions, and their tolerance for either acid or
material. Salt tolerance is also desirable.
If a site is to be reforested, it is still generally desirable to seed
it with a mixture of grasses and legumes. The initial grass and legume
cover helps to protect the site from erosion and surface runoff, and to
take up the nutrients supplied by the sludge. Planting slow growing
tree species is generally not recommended because they generally do not
compete well with the initial herbaceous cover. Fast growing hardwoods
such as hybrid poplars seem to survive and grow well because they can
usually compete successfully.
8.6.2 Seeding and Mulching
Herbaceous species can be seeded by direct drill or broadcast, hydro, or
aerial seeding. However, disturbed sites are often too rocky and irreg-
ular for drill seeding. Broadcast seeding is generally more desirable
because the stand of vegetation produced is more natural in appearance,
with a more uniform and complete cover, and effective in erosion preven-
tion and site stabilization. Broadcasting also achieves a planting
depth which is better suited to the variety of different-sized seeds
usually found in mixtures of species. Aerial broadcast seeding may also
be useful for large tracts. It is generally not necessary to cover the
8-11
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seed, since the first rainfall will normally push the seed into the
loosened surface spoil and result in adequate coverage.
On sites that have good topsoil, agricultural seeding rates can be used.
However, on abandoned sites, it may be necessary to apply much larger
amounts of seed (54).
Mulching is generally not necessary except on specific sites. Mulches
are defined as organic or inorganic materials applied to the soil sur-
face to protect the seed, reduce erosion, modify extremes in surface
spoil temperatures, and reduce evaporation. Mulching is generally ad-
visable on steep slopes and on black anthracite refuse or fly ash banks
in order to protect germinating vegetation from high surface tempera-
tures which may be lethal to most plants. Mulching may also be required
by some state regulatory agencies for specific situations. Materials
used for mulching are straw, hay, peanut hulls, corn cobs, bagasse,
bark, sawdust, leaves, and wood chips.
TABLE 8-2
HUMID EASTERN REGION VEGETATION
Various grasses, legumes, trees, and shrubs have been evaluated for use on disturbed lands in the
humid regions of the United States. Grass species that have shown promise for use on low pH soils
in the eastern United States include weeping lovegrass, bemtudagrass varieties, tall fescue, chew-
ings fescue, switchgrass, red top, colonial bentgrass, creeping bentgrass, velvet bentgrass, deer-
tongue, big bluestem, little bluestem, and brown sedge bluestem (4).
Some of the more agriculturally important grass species adapted to better soil conditions on dis-
turbed sites include: bromegrass, timothy, orchardgrass, perinnial rye grass, Italian ryegrass,
Kentucky bluegrass, Canadian bluegrass, Reed canarygrass, Dallisgrass, bahiagrass, and in special
situations, lawn grasses including Zoysia japonica Steud and Zoysia matrella. In addition to the
common grasses, several of the cereal grains, such as rye, oats, wheat, and barley have been used,
but mainly as companion crops (4).
Legume species tested on disturbed sites in eastern United States include alfalfa, white clovers,
crimson clover, birdsfoot trefoil, lespedezas, red clover, crownvetch, and hairy vetch. 'Other spe-
cies that have been successfully tested include flat pea, kura clover, zigzag clover, sweet clover,
and yellow sweet clover (4).
Several grass and legume mixtures have been used successfully in Pennsylvania to reyegetate drastic-
ally disturbed lands amended with municipal sludges. The primary mixture and seeding rate used for
spring and summer seeding is:
Kentucky-31 tall fescue
Orchardgrass
Birdsfoot trefoil
Total
Metric conversion factor:
1 kg/ha - 0.89 Ib/ac.
Amount
kg/ha
22
22
_n
55
8-12
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TABLE 8-2 (continued)
For late summer and early fall seeding the following mixture has been used successfully:
Kentucky-31 tall fescue
Orchardgrass
Winter rye (1 bu/ac)
Total
Metric conversion factor:
1 kg/ha = 0.89 Ib/ac.
Amount
kg/ha
11
5
jji
79
This mixture has usually been sufficient to establish a vegetative cover to protect the site over
the winter season. The following spring, an additional seed mixture, consisting of orchardgrass (11
kg/ ha; '9.8 lb/ ac) and birdsfoot trefoil (11 kg/ha; 9.8 Ib/ac), is applied. Other seeding mixtures
for spring, summer, and fall seeding are found in Ref. (48).
Several tree and shrub species have been utilized on disturbed land areas in the eastern United
States. However, in general, trees and shrubs have been planted either after the soil has been sta-
bilized with herbaceous species, like grasses and legumes, or has been planted with them. On cer-
tain drastically disturbed areas, trees may be the only logical choice of vegetation where a future
monetary return is expected. They do provide long-term cover and protection with little or no addi-
tional care and maintenance. The same precautions should be exercised in selecting tree species for
use on disturbed land sites as in selecting grasses and legumes. The soil acidity, plant nutrient
requirements, chemical and physical properties of the soil, site topographical influences, and other
environmental factors snould be considered.
Common tree and shrub species grown successfully on disturbed land sites in the eastern United
States include black locust, European black alder, autumm olive, white pine, scotch pine, Virginia
pine, short leaf pine, red pine, Norway spruce, European and Japanese larch, and bristly locust.
Other suitable hardwoods not as commonly used include yellow poplar, hybrid poplars, red oak, syca-
more, river birch, maples, cottonwoods, and aspens.
TABLE 8-3
DRIER MID-WEST AND WESTERN REGION VEGETATION
A large number of plant species have been tested on disturbed lands in the Intermountain Region of
the United States (6). Fewer species have been evaluated for reclamation use in the drier regions
of the United States. The objective in many reclamation plantings in the drier regions is to return
the area to climax vegetation. In almost every instance, the soils are not the same as before the
disturbance occurred, and it would seem in many cases that species lower in the successional stage
may be better adapted and more easily established on these sites. Whether a single species or a
mixture is selected depends on several factors, including the planned future use of the site, the
desire to have the planting blend with the surrounding vegetation, and the adaptability and compati-
bility of the species selected. The factors limiting the successful establishment of vegetation on
disturbed areas may be different on a site being reclaimed than on adjacent undisturbed areas, where
a plant species may be growing together in what appears to be a stable community. Even after the
species have been selected, the proportionate amounts of seeding are not easily determined. The suc-
cessful experiences of the past 40 years from seeding range mixtures and planting critical areas
appears to be the best guide to the opportunities for success of either single species or mixtures
(5). '
8-13
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TABLE 8-4
WESTERN GREAT LAKES
This region includes Wisconsin, eastern Minnesota, and the western upper peninsula of Michigan. The
common grasses, generally used in mixtures with a legume, are tall fescue, smooth brome, and timo-
thy. Kentucky bluegrass and orchardgrass are also well adapted. "Garrison" creeping foxtail and
reed canarygrass perform well on wet sites. The most commonly used legumes are birdsfoot trefoil
and crownvetch. Numerous species of woody plants can be used depending on specific site conditions.
Siberian crabapple, several species of poplars, tatarian and Amur honeysuckles, silky dogwood, red-
osier dogwood, European black alder, black cherry, and green ash perform well. Autumn olive is
adapted to the southern portion of this area.
TABLE 8-5
NORTHERN AND CENTRAL PRAIRIES
This is the region known as the Corn Belt.. Grasses adapted to the area are Kentucky bluegrass, tall
fescue, smooth brome, timothy, and orchardgrass. Reed canarygrass is adapted to wet areas. Switch-
grass, big bluestem, and Indiangrass are well adapted warm season natives. Birdsfoot trefoil, crown-
vetch, and alfalfa are commonly used legumes.
Wooay species that have been successful include autumnolive, European black alder, poplar species,
tatarian honeysuckle, Amur honeysuckle, black cherry, eastern red cedar, pines, oaks', black walnut,
green ash, black locust, black haw, and osage-orange.
TABLE 8-6
NORTHERN GREAT PLAINS
Tnts region includes most of the Dakotas and Nebraska west to the foothills of the Rocky Mountains
and includes northeastern Colorado. The native wheatgrass (western, thickspike, bluebunch, stream-
sant., and slender) are used extensively in seeding mixtures. Western wheatgrass should be included
in most mixtures, although for special purposes thickspike or streambank wheatgrass are more appro-
priate. Green needlegrass is an important component of mixtures except in the drier areas. On fa-
vorable sites big bluestem, little bluestem, and switchgrass provide opportunities for color or for
a different season of use. Prairie sandreed is adapted to sandy soils throughout the region. "Gar-
rison" creeping foxtail and reed canarygra-ss are adapted to wet sites.
Crested wheatgrass has been used extensively and is long-lived in this climate. Intermediate and
pubescent wheatgrasses are useful in establishing pastures. Tne use of smooth brome and tass fescue
1s limited to the eastern portions of the Northern Great Plains where the annual precipitation ex-
ceeds 50 cm (19.7 in). Alfalfa and white sweetclover are the only legumes used in most of the area
for reclamation plantings.
Many native and introduced woody plants are adapted for conservation plantings. Fallowing to pro-
vide additional moisture is required for establishment of most woody plants and cultivation must
generally be continued for satisfactory performance of all but a few native shrubs. These practices
may not be compatible with certain reclamation objectives, thereby limiting the use of woody species
to areas with favorable moisture situations. Some woody plants useful in this area, if moisture and
management are provided, are Russian-olive, green ash, skunkbush, sumac, Siberian crabapple, Manchur-
lan crabapple, silver buffaloberry, tatarian honeysuckle, chokecherry, Siberian peashrub, Rocky
Mountain juniper, and willow species. ,
8-14
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TABLE 8-7
SOUTHERN GREAT PLAINS
The Southern Great Plains are considered to be the area from southcentral Nebraska and southeastern
Colorado to central Texas. The most common native grasses of value in reclaiming drastically dis-
turbed lands include big bluestem, little bluestem, Indiangrass, switchgrass, buffalograss, blue
grama, sideoats grama, and sand lovegrass. Introduced bluestems such as yellow bluestem, Caucasian
bluestem, and introduced Kleingrasss blue panicgrass, and buffelgrass are important in the southern
and central portions of this plant growth region. Alfalfa and white sweetclover are the most com-
monly used legumes. Russian-olive is a satisfactory woody species in the northern portions and
along the foothills of the Rocky Mountains. Junipers, hackberry, and skunkbush sumac are important
native species. Osage-orange is well adapted to the eastern part of this area. Desirable woody
plants require special management for use on most drastically disturbed lands.
TABLE 8-8
SOUTHERN PLAINS
This area is the Rio Grande Plains of south and southwest Texas. The characteristic grasses on
sandy soils are seacoast bluestem, two-flow trichloris, silver bluestem, big sandbur, and tangle-
head. The dominant grasses on clay and clay loams are silver bluestem, Arizona cottontop, buffalo-
grass, curlymesquite, and grama grasses. Indiangrass, switchgrass, seacoast bluestem, and crinkle-
awn are common in the oak savannahs.
Old World bluestems, such as yellow and Caucasian bluestems, are satisfactory only where additional
moisture is made available. Natalgrass and two-flower trichloris have shown promise in reclamation
plantings.
TABLE 8-9
SOUTHERN PLATEAUS
The area is made up of the 750- to 2,400-m (2,450-. to 7,875-ft) altitude plateaus of western Texas,
New Mexico, and Arizona. The area includes a large variety of ecological conditions resulting in
many plant associations. Creosote-tarbush desert shrub, grama grassland, yucca and juniper savan-
nahs, pinyon pine, oak, and some ponderosa pine associations occur. Little bluestem, sideoats
grama, green sprangletop, Arizona cottontop, bush muhly, plains bristlegrass, vine-mesquite, blue
grama, black grama, and many other species are common and are useful in reclamation plantings, de-
pending on the site conditions and elevation.
TABLE 8-10
INTERMOUNTAIN DESERTIC BASINS
This region occupies the extensive intermountain basins from southern Nevada and Utah, north through
Washington, and includes the basin areas of Wyoming. The natural vegetation ranges from almost pure
stands of short grasses to desert shrub. There are extensive area dominated by big sagebrush or
other sagebrush species.
A wide variety of species of grasses is available for this area. Among the most commonly used spe-
cies are the introduced Siberian wheatgrass, crested wheatgrass, intermediate wheatgrass, pubescent
wheatgrass, tall wheatgrass, and hard fescue. Native grasses used include bluebunch wheatgrass,
beardless wheatgrass, big bluegrass, Idaho fescue, and Indian ricegrass. Four-wing and Nuttall
saltbush have performed well in planting trials. Available woody species are limited, though juni-
pers, Russian-olive, skunkbush sumac, and other native and introduced woody plants are adapted to
the climate where moisture is adequate.
8-15
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TABLE 8-11
DESERT SOUTHUEST
This is the desert of southwestern Arizona, southern Nevada, and southern California. Creosotebush
may occur in almost pure stands or with tarbush. Triangle bur-sage, white bur-sage, rubber rabbit-
brush, and ocotillo are prominent on some sites. Large numbers of annual and perennial forbs are
present. Saltbushes, winterfat, and spiny hopsage are common. The few grasses present in the under-
story are largely big galleta, desert saltgrass, grama grasses, and species of threeawns.
Only minor success has been obtained in establishing vegetation on disturbed lands in the desert
southwest. Irrigation for establishment may be essential in some areas, and the longevity of stands
when irrigation is discontinued is not known. Big galleta and bush muhly show promise. Native
shrubs such as creosotebush, fourwing saltbush, and catclaw have also been established. Reseedlng
annuals such as goldfields, California poppy, and Indianwheat have also shown promise.
TABLE 8-12
CALIFORNIA VALLEYS
The climate of the central California Valleys is classified as semiarid to arid and warm and the
moisture is deficient at all seasons. The largest area of grassland lies around the edge of the
central valley and is dominated by annual species. The only areas remaining in grass in the valley
are usually too alkaline for crop production. The grasses remaining in these sites are desert salt-
grass and alkali sacaton.
Recommended for seeding in the area of more than 40 cm (15.8 in) annual precipitation is a mixture
of "Luna" pubescent wheatgrass, "Palestine" orchardgrass, and rose clover. Crimson clover, Califor-
nia poppy, and "Blando" brome can be added.
Inland in the 30 cm (12 in) precipitation areas, a mixture of "Blando" brome, Wimmera ryegrass, and
"Lana" woolypod vetch is recommended. In the 15- to 30-cm (6 to 12 in) precipitation zone "Blando"
brome (soft chess) and rose clover are generally used.
8.7 Sludge Application Rates
8.7.1 General
Determining sludge application rates for reclaiming disturbed lands
often presents a conflict for the designer. When sludge is applied only
once, as is the case with reclamation of most drastically disturbed
lands, the many important limiting factor is usually the addition of po-
tentially toxic heavy metals. With a one-time sludge application, the
goal is to create a large pool of nutrients to supply the vegetation for
more than one year so that additional fertilizer amendments are not
needed. This makes it necessary to exceed the annual nitrogen require-
ment of the vegetation, and potentially results in nitrate movement to
ground water. The designer may seek a temporary exemption for the ni-
trogen limits from the applicable regulatory agency, because:
The large one-time sludge application is necessary to provide
a pool of nutrients to ensure future vegetation growth on the
disturbed land site. Without the large sludge application,
vegetation may not sufficiently establish itself, resulting in
8-16
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future erosion and surface water pollution. The large appli-
cation also provides organic matter which improves the long-
term fertility of the soil.
The potential for nitrate degradation of ground water is
slight because of favorable hydrogeological conditions at the
site (great depth to ground water, intervening impermeable
soil layers, high evaporation compared to precipitation rates,
high dilution in the aquifer, non-drinking water aquifer,
etc.).
If commercial fertilizers are used instead the potential for
ground water degradation may be greater than if sludge were
used. Sludge is a slow release fertilizer because the organic
nitrogen is mineralized over many years (see Appendix B).
If approved, the one-time sludge application rate is then based upon
total metal loadings. If nitrogen controls, however, then the proce-
dures in Chapter 6 or 7 apply for calculation of sludge application
rates.
8.7.2 Calculation of Sludge Application Rate Based'on Metal
Loading
To make a one-time sludge application rate calculation based on metal
loadings the designer needs the following information:
Current cumulative metal loading limits applicable to the
site. Although the limits shown in Table 6-2 are used in this
example, it is possible that different limits will be applica-
ble at the location and time the designer is making his calcu-
lations.
The cation exchange capacity (CEC) (see Table 6-2) and pH of
the soil, which should be made 6.5 or higher through lime ad-
dition, if necessary.
The metal analysis of the sludge for Pb, Zn, Cu, Ni, and Cd.
With the above information, and using Table 6-2 as an example of the as-
sumed total metal limits, a calculation of loading rate is made for each
metal:
ka
Metric tons sludge/ha = a
metal allowed/ha (Table 6-2)
mg metal/kg in sludge x.0.001
Tons sliiHap/ar - lb metal aTlowed/ac (Table 6-2)
Tons sludge/ac - mg metal/kg in Slud^e x 0.001'
x 0.4
8-17
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The lowest value generated from the five calculations (Pb, Zn, Cu, Ni,
or Cd) determines the maximum one-time sludge application rate based on
metal loadings. The design example in this chapter provides example
calculations.
8.8 Monitoring Requirements
8.8.1 General
In order to comply with state, local, and federal requirements for land
application of sludge, both the sludge to be utilized and the site char-
acteristics must be evaluated. If the land application system complies
with applicable criteria, it can generally be assumed that the sludge
will pose little probability for adverse effects on the environment and
minimal monitoring should be necessary. However, some states require
additional site monitoring after the sludge has been applied.
8.8.2 Suggested Minimal Monitoring Program
8.8.2.1 Background Sampling (Pre-Sludge Application)
Composite soil samples should be collected from the site for the deter-
mination of pH, liming requirements, CEC, available nutrients and trace
rnetals prior to sludge addition. Water samples from surface streams,
lakes, etc., and private household wells in the area should be analyzed
for nutrients and trace metals prior to sludge application. Composite
sludge samples should be collected and analyzed to provide data for use
in designing loading rates.
8.8.2.2 Sampling During Sludge Applicable
As the sludge is delivered, grab samples should be taken and analyzed
for moisture content to adjust the delivered amount of sludge to the de-
sign rate if there is variation in the sludge moisture content. Compo-
site sludge samples should be collected as the sludge is applied, to do-
cument the actual nutrient and trace metal application rate.
8.8.2.3 Post-Sludge Application Monitoring
Monitoring of the sludge application site after sludge has been applied
can vary from none to extensive, depending on state and local regula-
tions and site-specific conditions. Generally, it is desirable to ana-
lyze the soil after 1 year for soil pH changes and heavy metals (if re-
quired). In addition, surface and ground water analysis for nitrogen
forms and trace metals may be needed.
Some states have very specific requirements for monitoring, so the de-
signer should consult the appropriate regulatory agency. Monitoring re-
quirements by the State of Pennsylvania are given (43), as an example:
The monitoring system for each contiguous parcel (up to 40 ha; 100 ac)
of land to receive sludge consists of one down-gradient ground water
8-18
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well and on-site lysimeters. The well location is selected after the
ground water flow pattern is determined. Lysimeters are installed at
four locations selected to be representative of overall site conditions.
Two lysimeters are installed at each location. Lysimeters are installed
to collect soil percolate water at the 90 cm (36 in) depth. It is de-
sirable to have a minimum of three samples from each site for statisti-
cal evaluation. The fourth installation is a safeguard. Wells of near-
by private homes are sampled periodically before and after sludge is ap-
plied. Large diverse sites (over 40 ha; 100 ac) are subdivided into
smaller parcels for monitoring purposes. Sets of lysimeters (4 sta-
tions) are installed in each parcel.
Table 8-13 is a minimum list of parameters that should be included in
the routine analysis of water, soils, and vegetation. Additional parame-
ters may be included in the analyses if specified on a case-by-case
basis (43).
TABLE 8-13
WATER SAMPLE COLLECTION
1. A minimum of three samples are collected from each ground water well and lysimeter station prior
to sludge application on the site.
2. After sludge application, water samples are collected monthly for a period of 1 year.
3. Samples collected prior to sludge application and for the first ,3 months following sludge appli-
cation are analyzed for pH, Cl, N03-NS NH4-N, Org-N, Fe, Al, Mn, Cu, Cr, Co, Pb, Cd, Ni, Zn, and
fecal coliforms.
4. Water samples collected during the 4th month to the llth month following sludge application are
analyzed only for pH, nitrogen forms (NH4-N, NQ3-N), trace metals (Zn, Cu, Pb, Co, Ni, Cd, Cr),
and fecal coliforms.
5. Water samples collected during the 12th month following sludge application are analyzed for con-
stituents listed in No. 3, above.
6. Water sampling is terminated after one year unless results of the third quarterly report indi-
cate a need to continue sampling. If further sampling is required, samples are collected quar-
terly until sufficient data are collected to formulate a conclusion on the problem.
7. The monitoring well is maintained past the initial year of sampling to allow for the collection
of samples at a later date, if deemed necessary.
Soil Sample Collection
1. Soil samples are collected on the site prior to sludge application. Surface soil samples of the
topsoil material are collected throughout the site and analyzed for buffer pH to determine lime
requirements to raise the soil pH to 6.5 and to determine the cation exchange capacity. Samples
from the complete soil profile are collected from the pits excavated to install the lysimeters.
Soil samples are collected from the 0 to 15 (0 to 6 in), 15 to 30 (6 to 12 in), 30 to 60 (12 to
24 in), and 60 to 90 cm (24 to 36 in) soil depth.
2. Soil samples are again collected one year following sludge application. Samples are collected
at the 0 to 15 (0 to 6 in), 15 to 30 6 to 12 in), and 30 to 60 cm (12 to 24 in) depth.
3. All soil samples are analyzed for pH, Bray P, Ca, Mg, K, Na, Fe, Al, Mn, Cu, Zn, Cr, Co, Pb, Cd,
Ni, and Kjeldahl nitrogen.
4. At the end of the second year after sludge application, surface soil samples are collected and
analyzed for pH to determine if it is still at pH 6,5.
8-19
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TABLE 8-13 (continued)
Vegetation Sampling
i. Vegetation samples are collected for foliar analyses at the end of the first growing season fol-
lowing sludge application. Separate samples are collected for each of the seeded species. All
samples are analyazed for N, P, K, Ca, Mg, Fe, Al, Mn, Cu, Zn, Cr, Co, Pb, Cd, and Ni.
2. For sites seeded in the fall, vegetation samples are collected at the end of the following grow-
ing season.
8.9 Sludge Application Methods and Scheduling
8.9.1 Transportation
Chapter 10 of this manual discusses sludge transport in detail. A spe-
cial consideration in transport of sludge to reclaim mined land is that
the potential may exist to backhaul sludge, i.e., to use the same
trucks, railcars, etc., which transport the mined ore to the city for
transport of the sludge from the city back to the mining area. For
example, in 1981-82, the city of Philadelphia backhauled about 54,432 mt
(60,000 T) of sludge annually in coal trucks a distance of 450 km (280
mi) to help reclaim strip mine sites in western Pennsylvania (56).
8.9.2 Site Preparation Prior to Sludge Application
Under federal and state mining regulations, the disturbed mine sites
generally must be graded after mining to the approximate original con-
tour of the area. Abandoned areas where no regrading has been done,
should also be regraded to a relatively uniform, slope of less than 15
percent prior to sludge application.
8.9.2.1 Scarification
Prior to sludge application, the surface should be roughened or loosened
to offset the compaction caused during the leveling or grading opera-
tion. This will help to improve the surface water infiltration and per-
meability, and slow the movement of any surface runoff and erosion. A
heavy mining disk or chisel plow is typically necessary to roughen the
surface. It is advisable that this be done along contour.
8.9.2.2 Erosion and Surface Runoff Control Measures
Surface runoff and soil erosion from the sludge application site should
be contolled. These measures may include erosion control blankets, fil-
ter fences, straw bales, and mulch. It may be necessary to construct
diversion terraces and/or sedimentation ponds. The local Soil Conserva-
tion Service can be contacted to aid in the design of the erosion and
surface runoff control plans. In addition, see Chapter 10 of this man-
ual .
8-20
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8.9.3 Methods of Application
Methods of sludge application to land are discussed in Chapter 10.
8.9.4 Scheduling
The timing of sludge application depends on the climate, soil condi-
tions, and growing season. It is generally not advisable to apply
sludge to frozen or snow-covered ground, since it cannot be immediately
incorporated and seeded. If the sludge is applied to frozen or snow
covered ground and allowed to remain on a sloped surface, the chances of
surface runoff are increased as the snow melts or if a heavy rain storm
occurs. The sludge should not be applied during periods of heavy rain-
fall since this greatly increases the chances of surface runoff. Sludge
should not be applied in periods of prolonged extreme heat or dry con-
ditions, since considerable amounts of nitrogen will be lost before the
vegetation has a chance to establish itself. If sludges are applied and
allowed to dry on the soil surface, from 20 to 70 percent of the NH^-N
will be volatilized and lost to the atmosphere as NHU. The exact amount
of NH4-N lost will depend on soil, sludge, and climate conditions (53).
Sludge applications should be scheduled to accommodate the growing sea-
son of the selected plant species. If the soil conditions are too wet
when sludge is applied, the soil structure may be damaged, bulk density
increased, and infiltration decreased due to heavy vehicle traffic on
the wet soiU This may increase the possibility of soil erosion and
surface runoff. Also the tractors or trucks may experience difficulty
driving on the wet soil.
If the area to receive sludge is covered under federal or state mining
regulations, the sludge application must be scheduled to comply with the
revegetation regulations. For example, in Pennslvania mined land can be
seeded in the spring as soon as the ground is workable, usually early in
March, but seeding must terminate by May 15. Late summer seeding season
is from August 1 until September 15. In Pennsylvania, sludge applica-
tion and seeding of mined land covered by these regulations must comply
with these requirements. The designer should check on requirements for
his locale.
8.9.4.1 Storage
Some need for sludge storage will be likely. It may be either at the
treatment plant and/or at the application site. In general, when liquid
sludge is used, storage is provided at the treatment plant in digesters,
holding tanks, or lagoons. At application sites where large quantities
of sludge are utilized, storage lagoons may be built at the utilization
site.
If dewatered sludge is used, storage may be more advantageously stored
at the application site. Small storage areas are desirable at the
treatment plant for times of inclement weather or equipment breakdown.
8-21
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At currently mined sites, it may be necessary to transport and stockpile
dewatered sludge at the site while the area is being backfilled and top-
soiled. This would allow large quantities of sludge to be applied in a
relatively short period of time. Stockpiling of sludge at the site
prior to application would allow for more efficient utilization of man-
power and equipment for spreading large quantities of sludge in a short
period of time. Some states have specific regulations concerning sludge
stockpiling on the site for short periods of time. For example, in
Pennsylvania, the sludge storage area must be diked to prevent surface
water from running into or out of the storage area.
8.9.4.2 Other Conditions
Some states have included various conditions that must be met in order
to be granted a permit to apply sludge to disturbed land. For example,
some states do not allow sludge to be utilized for the revegetation of
inactive mines or active coal refuse piles on slopes exceeding 15 per-
cent. Dairy cattle may not be allowed to graze the land for at least
two months after sludge application. Many states have regulations con-
cerning buffer areas where sludge cannot be applied. Pennsylvania re-
quires that sludge cannot be applied within 30 m (98 ft) of streams, 90
m (300 ft) of water supplies, 8 m (26 ft) of bedrock outcrop, 15 m (50
ft) of property lines, or 90 m (300 ft) of occupied dwellings. In addi-
tion to sludge management regulations, if the site is an actively mined
area, all mining regulations concerning revegetation must also be con-
sidered in the design of the sludge utilization project.
8.10 Design Example for Sludge Application to Disturbed Land
It is intended to reclaim on a trial basis a portion of a drastically
disturbed areas with a one-time application of sludge. The single large
application should provide organic matter and nutients required to sup-
port establishment of a mixture of grass and legumes. The site may in
the future be used for agricultural purposes, so the cumulative (total)
metal loadings are a design concern. The state regulatory agency is
aware that the one-time heavy application of sludge may result in tem-
porary leaching of excess nitrates to the ground water, and requires
monitoring to quantify the impact.
8.10.1 Sludge Characteristics
The sludge to be applied is an anaerobically digested, dewatered sludge
with an average analysis on a dry weight basis, as follows:
Solids - 54%
Total N - 1.5%
NH4-N - 0.6%
Total P - 0.5%
Total K - 0.1%
Pb - 500 mg/kg
Zn - 2,000 mg/kg
Cu - 500 mg/kg
Ni - 100 mg/kg
Cd - 50 mg/kg
8-22
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8.10.2 Site Characteristics
Location: Mid-Atlantic
Area: 2 ha (5 ac)
Soil pH: 3.9
Soil CEC: 13 meq/100 g
Soil Permeability: 0.2
Depth to Ground Water:
Annual Precipitation:
State
cm/hr
5 m (16 ft)
80 cm (31.5 in)
8.10.3 Calculation of Maximum Sludge Application Rate Based on
Metal Loadings
Table 6-2 presents suggested cumulative limits for metals applied to
agricultural cropland as a function of soil CEQ. For convenience, these
suggested limits are repeated below for soil CEQ in the range 5-15 meq/
100 g, typical of the design site soil:
Pb - 1,120 kg/ha (1,000 Ib/ac)
Zn - 560 kg/ha (500 Ib/ac
Cu - 280 kg/ha (250 Ib/ac)
Ni - 280 kg/ha (250 Ib/ac)
Cd - 10 kg/ha (8.9 Ib/ac)
Combining the above metal loading limits with the sludge characteristics
in the equation below allows determination of the maximum loading for
the limiting metal :
mt sludge/ha =
kg/ha metal allowed
(0.001) (mg/kg metal in sludge)
For zinc:
mt
= 28° mt/ha
Using similar calculations, the loading limits for all of the metals are
as follows:
Metal
Pb
Zn
Cu
Ni
Cd
Maximum Sludge Application Rate
Mt/Ha T/Ac
2S240
280
560
2,800
200
999
125
250
1,250
89
8-23
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Cadmium is the limiting metal in this case, allowing a maximum sludge
application of 200 mt/ha (89 T/ac).
8.10.4 Lime Application Determination
Based upon appropriate soils tests, it was determined that agricultural
lime application of 12.3 mt/ha (5.5 T/ac) is sufficient to raise the
soil pH to 6.5.
8.10.5 Calculation of Nutrient Application
The nutrient content of the 200 mt/ha (89 T/ac) of sludge applied is
calculated as follows:
Nutrient Applied in kg/ha = % Nutrient in Sludge x Application
Rate x 10
Using a similar calculations for the other nutrients:
Total N = 3,000 kg/ha (2,670 Ib/ac)
NH4-N = 1,200 kg/ha (1,068 Ib/ac)
Organic N = 3,000-1,200 = 1,800 kg/ha (1,602 Ib/ac)
Total P = 1,000 kg/ha (890 Ib/ac)
Total K = 200 kg/ha (178 Ib/ac)
8.10.5.1 Calculation of Potential Nitrate Leaching into the
Ground Water
It is possible to make a conservative estimate of the quantity of ni-
trates potentially leaching into the ground water by (1) calculating the
available nitrogen added by the sludge application, (2) subtracting the
estimated nitrogen uptake by the vegetation and other nitrogen losses,
and (3) calculating the maximum potential concentration of excess ni-
trates percolating from the site into the underlying aquifer.
Step 1 is to calculate the available nitrogen in the first year and suc-
ceeding years from a one-time sludge application of 200 mt/ha (89 T/ac):
NH4-N applied = 1,200 kg/ha (1,068 Ib/ac)
Organic N applied = 1,800 kg/ha (1,602 Ib/ac)
All of the NH4-N applied is assumed to be available in the first year.
As discussed in Section 6.4.3.1, a fraction (percentage) of the organic
nitrogen applied mineralizes during the first year after sludge applica-
tion, and each year thereafter. Referring to Table 6-7, it is assumed
for this design example that the organic N mineralization rates are:
first year - 20%; second year - 10%; third year - 5%; succeeding years -
3% each year.
8-24
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Experience with wastewater irrigation indicates that about 10 to 15%of
the nitrogen available is lost by unaccounted for means (13). The path-
ways suggested are volatilization and denitrification. It is conserva-
tive to assume that similar unaccounted for losses of 10% will occur
with incorporated sludges applied on a one-time basis, since the miner-
alization of organic N will make ammonia-N available for volatilization
or nitrification. This nitrogen reduction applies only to the inorganic
nitrogen fraction in the sludge/soil mixture mixture, and should not be
taken if specific reductions for volatilization and/or denitrification
have previosuly been deducted. -:
First Year Calculation:
NH4-N 1,200 kg/ha
Organic N (1,800 kg/ha)
x 20% mineralization rate
Subtotal
Deduct for unaccountable losses (10%)
Deduct for vegetation uptake
Total excess available N
in the first year
Second Year Calculation:
NH4-N 0 kg/ha
Organic N remaining (1,440 kg/ha)
x 10% mineralization rate
Subtotal
Deduct for unaccountable losses (10%)
Deduct for vegetation uptake
360 kg/ha
1,560 kg/ha
(156) kg/ha
(300) kg/ha
1,104 kg/ha (983 Ib/ac)
144 kg/ha
144 kg/ha
(14) kg/ha
(300) kg/ha
Total excess available
in the second year
-170 kg/ha
(There is a deficit, not an excess in the second year)
Ground water contamination from leaching of excess available nitrogen is
only a concern during the first year after sludge application. A very
conservative estimate can be made of the concentration of nitrates in
the percolate from the site during the first year. This calculation as-
sumes that all of the excess nitrogen is converted to nitrates, and
there is no dilution of percolate by existing ground water.
Assume 80 cm annual net precipitation.
Assume 12% evaporation losses.
8-25
-------
If all of the excess nitrogen in the sludge applied is mobile (an un-
likely and very conservative assumption), the concentration of nitrate
in the percolate is calculated below:
(1.104 kg/ha) (106 mg/kg) (1.000 cm3/!) =
(108 cm2/ha) (80 cm) (0.80)
mg/]
A potential concentration of 172 mg/1 of nitrate nitrogen in the perco-
late from the site during the first year after sludge application may be
unacceptable to the regulatory agency, even though the contamination is
a temporary 1-year effect, and there is no extraction of potable water
from the aquifer.
8.10.5.2 Recalculation of Sludge Application Rate Based on
Percolate Nitrate Concentration
Assuming that the regulatory agency allows no higher than 10 mg/1 of
nitrate concentration in the percolate from the site, the maximum excess
available nitrogen application rate which will achieve this limit can be
calculated:
Max. Excess Avail. N =
(10 mg/1) (103 cm2/ha) (80 cm) (0.80) =
(106 mg/ha) (1,000 cm3/!)
Maximum allowable excess N
(from above calculation)
Vegetation nitrogen uptake
(determined previously)
Subtotal
Unaccountable nitrogen losses
(assumed previously)
Total allowable available N application
kg/ha
64 kg/ha
300 kg/ha
364 kg/ha
36 kg/ha
400 kg/ha (365 Ib/ac)
The sludge application rate corresponding to application of 400 kg/ha
(356 Ib/ac) of available nitrogen is calculated using the following
equation:
Mr
-------
As previously noted, the above calculation procedure results in a very
conservative sludge application rate. See the Venango, Pennsylvania,
case study in Appendix D for first year and long-term nitrate measure-
ments in the ground water at an actual site similar to that used for
this design example.
8.11 References
1. Aldon, E. F. Use of Organic Amendments for Biomass Production on
Reclaimed Strip Mines in the Southwest. In: Land Reclamation and
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University Press, University Park, 1982. pp. 317-320.
2. All away, W. H. Agronomic Controls Over the Environmental Cycling
of Trace Metals. Adv. Agron., 20:235-271, 1968.
3. Barnhisel, R. I. Sampling Surface-Mined Coal Spoils. AGR-41,
University of Kentucky Department of Agronomy, Lexington, 1975. 4
pp.
4. Bennett, 0. L., E. L. Mathias, W. H. Armiger, and
Plant Materials and Their Requirements for Growth
In: Reclamation of Drastically Disturbed Lands.
and P. Sutton, eds. American Society of Agronomy.
sin, 1978. pp. 285-306.
J. N. Jones, Jr.
in Humid Regions.
F. W. Schaller
Madison, Wiscon-
5. Berg, W. A. Limitations in the Use of Soil Tests on Drastically
Disturbed Lands. In: Reclamation of Drastically Disturbed Lands,
F. W. Schaller and P. Sutton, eds. American Society of Agronomy,
Madison, Wisconsin, 1978. pp. 653-664.
6. Berry, C. R. Sewage Sludge Aids Reclamation of Disturbed Forest
Land in the Southeast. In: Land Reclamation and Biomass Produc-
tion with Municipal Wastewater and Sludge. W. E. Sopper, E. M.
Seaker, and R. K. Bastian, eds. Pennsylvania State University
Press, University Park, 1982. pp. 307-316.
7. Bledsoe, C. S., ed. Municipal Sludge Application to Pacific North-
west Forest Lands. Contribution 41, Institute of Forest Resources,
University of Washington, Seattle, 1981. 155 pp.
8. Blessin, C. W., and W. J. Garcia. Heavy Metals in the Food Chain
by Translocation to Crops Grown on Sludge-Treated Strip Mine Land.
In: Utilization of Municipal Sewage Effluent and Sludge on Forest
and Disturbed Land. W. E. Sopper and S. W. Kerr, eds. Pennsyl-
vania State University Press. University Park, 1979. pp. 471-482.
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8-27
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19
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State University Press, University Park, 1982. pp. 400-409.
Cole, D. W. Response of Forest Ecosystems to Sludge and Wastewater
Applications: A Case Study in Western Washington. In: Land Rec-
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sylvania State University Press, University Park, 1982. pp. 274-
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of Sewage Sludge As a
Surface Mined or Coal.
face Mining Hydrology,
of Kentucky, Lexington,
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Spoil Amendment in the Reclamation of Lands
In: Proceedings of the Symposium on Sur-
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1981. pp. 187-192.
Fitzgerald, P. R. Effects of Natural Exposure of Cattle and Swine
to Anaerobically Digested Sludge. In: Land Reclamation and Bio-
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8-28
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20. Franks, W. A., Persinger, A. lob., and P. Inyangetor. Utilization
of Sewage Effluent and Sludge to Reclaim Soil Contaminated by Toxic
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birds Nesting on Sludge-Treated Spoils. In: Utilization of Muni-
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Properties of Coal Refuse As Affected by Deep Incorporation of Sew-
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cite Refuse Banks with Heat-Dried Sewage Sludge. In: Utilization
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tian, eds. Pennsylvania State University Press, University Park,
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Lejcher, T. R., and S. H. Kunkle. Restoration of Acid Spoil Banks
with Treated Sewage Sludge. In: Recycling Treated Municipal
Wastewater and Sludge Through Forst and Cropland. W. E. Sopper and
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Park, 1973. pp. 165-178. .
8-30
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36. Lue-Hing, C., S. J. Sedita, and K. C. Rao. Viral and Bacterial
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Disturbed Land. W. E. Sopper and S. N. Kerr, eds. Pennsylvania
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38. McCormick, F. Y., and L. H. Borden. Percolate from Spoils Treated
with Sewage Effluent and Sludge. In: Ecology and Reclamation of
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Breach, New York, 1973. Vol. 1, pp. 239-250.
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Land, Champaign, Illinois, July 1973. pp. 121-128.
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Production with Municipal Wastewater and Sludge. W. E. Sopper, E.
M. Seaker, and R. K. Bastian, eds. Pennsylvania State University
Press, University Park, 1982. pp. 410-420.
41. Municipal Sludge Management: Environmental 'Factors. EPA 430/9-77-
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tional Technical Information Service, Springfield, Virginia, PB-277
622)
42. Paone, J., P. Struthers, and W. Johnson. Extent of Disturbed Lands
and Major Reclamation Problems in the United States. In: Reclama-
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11-22.
43. Pennsylvania Department of Environmental Resources, interim,Guide-
lines for Sewage Sludge Use for Land Reclamation. In: Rules and
Regulations of the Department of Environmental Resources, Common-
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44. Permanent Regulatory Program Implementing Section 501(b) of the
Surface Mining Control and Reclamation Act of 1977; Final Environ-
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45. Peterson, J. R., C. Lue-Hing, J. Gschivind, R. I. Pietz, and D. R.
Zenz. Metropolitan Chicago's Fulton County Sludge Utilization Pro-
gram. In: Land Reclamation and Biomass Production with Municipal
Wastewater and Sludge. W. E. Sopper, E. M. Seaker, and R. K. Bas-
tian, eds. Pennsylvania State University Press, University Park,
1982. pp. 322-338.
46. Peterson, J. R., R. I. Pietz, and C. Lue-Hing. Water, Soil, and
Crop Quality of Illinois Coal Mine Spoil Amended with Sewage
Sludge. In: Utilization of Municipal Sewage Effluent and Sludge
on Forest and Disturbed Land. W. E. Sopper and S. N. Kerr, eds.
Pennsylvania State University Press, University Park, 1979. pp.
359-368.
47. Plummer, A. P. Revegetation of Disturbed Intermountain Area Sites.
In: Reclamation and Use of Disturbed Land in the Southwest. J. L.
Thames, ed. University of Arizona Press, Tucson, 1977. pp. 302-
339.
48. Rafaill, B. L. and W. G. Vogel. A Guide for Vegetating Surface-
Mined Lands for Wildlife in Eastern Kentucky and West Virginia.
FWS/OBS-78-84, U.S. Fish and Wildlife Service, 1978. 89 pp.
49.
50.
51.
Roth, P. L., B. D. Jayko, and G. T. Weaver. Initial Survival and
Performance of Woody Plant Species on Sludge-Treated Spoils of the
Palzo Mine. In: Utilization of Municipal Sewage Effluent and
Sludge on Forest and Disturbed Land. W. E. Sopper and S. N. Kerr,
eds. Pennsylvania State University Press, University Park, 1979.
pp. 389-394.
Roth, P. L., G. T. Weaver, and M. Morin. Restoration of a Woody
Ecosystem on a Sludge-Amended Devastated Mine-Site. In: Land Rec-
lamation and Biomass Production with Municipal Wastewater and
Sludge. W. E. Sopper, E. M. Seaker, and R. K. Bastian, eds. Penn-
sylvania State University Press, University Park, 1982. pp. 368-
385.
Scanlon, D. H., C. Duggan, and S. D.
Compost for Strip Mine Reclamation.
Bean. Evaluation of Municipal
Compost Sci.} 14(3):4-8, 1973.
52. Schneider, K. R., R. J. Wittwer, and S. B. Carpenter. Trees Re-
spond to Sewage Sludge in Reforestation of Acid Spoil. In: Pro-
ceedings of the Symposium on Surface Mining Hydrology, Sedimentol-
ogy, and Reclamation, University of Kentucky, Lexington, December
1981. pp. 291-296.
53. Sludge Treatment and Disposal. Vol. 2. EPA-625/4-78-012, Environ-
mental Research Information Center, Cincinnati, Ohio, October 1978.
pp. 57-112. (Available from National Technical Information Ser-
vice, Springfield, Virginia, PB-299 593)
8-32
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54. Sopper, W. E., and E. M. Seaker. A Guide for Revegetation of Mined
Land in the Eastern United States Using Municipal Sludge. Pennsyl-
vania State University Institute for Research on Land and Water Re-
sources, May 1983.
55. Sopper, W., and St N. Kerr. Mine Land Reclamation with Municipal
Sludge - Pennsylvania Demonstration Program. In: Land Reclamation
and Biomass Product with Municipal Wastewater and,Sludge. W. E.
Sopper, E. M. Seaker, and R. K. Bastian, eds. Pennsylvania State
University Press, University Park, Pennsylvania, 1982. pp. 55-74.
56. Sopper, W. E., S. N. Kerr, E. M. Seaker, W. F. Pounds, and D. T.
Murray. The Pennsylvania Program for Using Municipal Sludge for
Mine Land Reclamation. In: Proceedings of the Symposium on Sur-
face Mining Hydrology, Sedimentology, and Reclamation, University
of Kentucky, Lexington, December 1981. pp. 283-290.
57. Stucky, D. 0., and T. S. Newman. Effect of Dried Anaerobically Di-
gested Sewage Sludge on Yield and Element Accumulation of Fall Fes-
cue and Alfalfa. J. Environ. Qual., 6:271-273, 1977.
58. Stucky, D. J., and J. Bauer. Establishment, Yield, and Ion Accumu-
lation of Several Forage Species on Sludge-Treated Spoils of the
Palzo Mine. In: Utilization of Municipal Sewage Effluent and
Sludge on Forest and Disturbed Land. W. E. Sopper and S. N. Kerr,
eds. Pennsylvania State University Press, University Park, 1979.
pp. 379-387. . -
59. Sundberg, W. J., D. L. Borders, and G. L. Albright. Changes in
Soil Microfungal Populations in the Palzo Strip Mine Spoil Follow-
ing Sludge Application. In: Utilization of Municipal Sewage Ef-
fluent and Sludge on Forest and Disturbed Land. W. E. Sopper and
S. N. Kerr, eds. Pennsylvania State University Press, University
Park, 1979. pp. 463-469.
60. Surface Coal Mining and Reclamation Permanent Program Regulations:
Revegetation (30 CFR Parts 816 and 817). Federal Register, March
23, 1982.
61. Sutton, P., and J. P. Vimmerstedt. Treat Stripmine Spoils with
Sewage Sludge. Ohio Report, 58:121-123, 1973.
62.
Svoboda, D., G. Smout, G. T. Weaver, and P. L. Roth. Accumulation
of Heavy Metals in Selected Woody Plant .Species on Sludge-Treated
Strip Mine Spoils at the Palzo Site, Shawnee National Forest. In:
Utilization of Municipal Sewage Effluent and Sludge on Forest and
Disturbed Land. W. E. Sopper and S. N. Kerr, eds. Pennsylvania
State University Press, University Park, 1979. pp. 395-405.
63.
Thornthwaite, C. W. An Approach Toward
of Climate. Geogr. R., 38:55-94, 1948.
a Rational Classification
8-33
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64. Tunison, K. W., B. C. Bearce, and H. A. Menser, Jr. The Utiliza-
tion of Sewage Sludge: Bark Screenings Compost for the Culture of
Blueberries on Acid Minespoil. In: Land Reclamation and Biomass
Production with Municipal Wastewater and Sludge. W. E. Sopper, E.
M. Seaker, and R. K. Bastian, eds. Pennsylvania State University
Press, University Park, 1982. pp. 195-206.
65. U.S. Soil Conservation Service. The Status of Land Disturbed by
Surface Mining in the United States. SCS-TP-158. Washington,
D.C., 1977. 124 pp.
66. Urie, D. H., C. K. Losche, and F. D. McBride. Leachate Quality in
Acid Mine-Spoil Columns and Field Plots Treated with Municipal Sew-
age Sludge. In: Land Reclamation and Biomass Production with
Municipal Wastewater and Sludge. W. E. Sopper, E. M. Seaker, and
R. K. Bastian, eds. 'Pennsylvania State University Press, Univer-
sity Park, 1982. pp. 386-398.
67. Younos, T. M., and M. D. Smolen. Simulation of Infiltration in a
Sewage Sludge Amended Mine Soil. In: Proceedings of the Symposium
on Surface Mining Hydrology, Sedimentology, and Reclamation, Uni-
versity of Kentucky, Lexington, December 1981. pp. 319-324.
8-34
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CHAPTER 9
PROCESS DESIGN FOR SLUDGE APPLICATION TO LANDS
DEDICATED FOR DISPOSAL
9.1 General
A OLD project has the following general characteristics:
4.
5.
The primary purpose of the site is long-term sludge applica-
tion, i.e., it is a dedicated disposal site for land spreading
of sludge. Any additional site activities or benefits, such as
growing of agricultural crops or improvement of soil character-
istics, are secondary to the primary sludge application activ-
ity.
Typically, sludge application rates are substantially higher
than used for the agriculture, forest and disturbed land op-
tions discussed in previous chapters. There may be some over-
lap, however, in specific cases, especially where crops are
grown on the site. Higher application rates reduce the area of
land required and may also simplify sludge distribution.
Typically, the agency which is implementing the project owns
the site, or has a long-term lease which allows the agency sub-
stantial discretion in use of the land for sludge spreading
purposes.
The site is more carefully designed,
than are sites using other options.
managed, and monitored
Site design and operations are focused upon containing within
the site any environmentally detrimental sludge constituents.
Surface runoff, ground water leachate, and harvested crops (if
any) are controlled to prevent adverse effects. Regulatory
agency limits and controls are virtually always required, and
permitting procedures often involve many governmental agencies.
Sludge for OLD site application should be stabilized to minimize odors,
vector breeding, and pathogen transmission. Once stabilized, sludge can
be applied to the dedicated site either in liquid or dewatered form.
This chapter discusses the OLD process design, and includes regulatory
considerations, site investigation, determination of application rates,
site preparation, application methods, monitoring needs, and site clo-
sure. A design example is provided at the end of the chapter. Most of
the discussion pertains to sites where the sludge application rates
greatly exceed agricultural utilization rates.
9-1
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9.2 Regulatory Considerations
Regulations pertinent to
Chapter 4, Section 4.3.
sludge application to land are detailed in
Usually, the use of land as a OLD must be recorded in the property deed
so future owners will know that the site soil characteristics have been
altered. This should be checked with the appropriate local authorities
agency.
A number of regulatory agencies may be involved in the site approval and
permitting process. As an example, Table 9-1 lists eight agencies which
were involved in permit approvals prior to construction of a OLD project
at Sacramento, California. A typical OLD project requires substantial
interaction with many agencies, and the designer must keep appraised of
all applicable regulations through early coordination with agency
staffs.
TABLE 9-1
PERMITS AND APPROVALS NEEDED PRIOR TO CONSTRUCTION
OF A OLD PROJECT AT SACRAMENTO, CALIFORNIA (1)
Agency
California Regional Water Quality
Control Board, Central Valley Re-
gion
State Department of Water Resources
U.S. Army Corps of Engineers
State Department of Fish and Game
State Solid Waste Management Board
County Division of Water Resources
County Water Agency
County Planning Department
Approval
Waste discharge requirements
Dam safety permits may be required
depending upon sludge storage pond
volume above grade
Section 404 permits for filling wet-
lands
Stream alteration permit and filling of
wetlands
County Solid Waste Management plan
amendment
Approval for modifications to flood-
plain
Approval for drainage modifications
Special use permit prior to construc-
tion
9.3 Public Participation
The principals of public participation programs for sludge to land proj-
ects are detailed in Chapter 3. Virtually all proposed OLD projects
will undergo an extensive public participation process, and the project
proponents should show that the OLD option is the most suitable in terms
of economics, technical feasibility, and environmental impact.
9-2
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9.4 Basic Types of Dedicated Land Disposal Site Designs
Figure 9-1 shows the basic alternatives for consideration in OLD
design. A brief description of each alternative is provided below:
site
Alternative 1 - All surface water runoff is contained within the site
through use of dikes, lagoons, etc., and disposed through evaporation.
All ground water leachate is contained beneath the site due to
natural impervious geological barrier (e.g., impervious clay,
bedrock, etc.) between the site and useful aquifers. In some
site specific cases, the aquifers potentially affected by the
site may already contain useless water and protection of these
aquifers is of no concern.
Sludge liquid removal is entirely by evaporation.
Sludge constituent removal is by utilization, bacterial activ-
ity, and chemical/physical reactions with the soil.
Sludge constituents not removed by the above mechanics accumu-
late in the soil profile.
Alternative 2 - Same as 1 above, except crops (e.g., grasses, clover,
etc.)are planted to enhance moisture removal through evapotranspira-
tion. The crops, in addition, remove a portion of many sludge nutrients
and other constituents through plant uptake mechanisms. Harvesting, re-
moval, and controlled use or disposal of crops can remove from the site
those sludge constituents incorporated into the crops.
Alternative 3 - Same as 1 or 2 above, except provision is made for con-
trolled discharge of surface runoff off-site. Controlled discharge is
achieved by adequate storage, treatment if necessary, monitoring, and
other requirements of the NPDES permitting procedure. In some cases, it
may be feasible to provide a controlled discharge back into the sewage
treatment system.
Alternative 4 - Same as 1, 2, or 3 above, except that ground water
leachate is intercepted and not allowed to percolate to ground water
aquifers. Interception mechanisms are usually subsurface drain tiles.
Under favorable geological conditions, interceptor ditches, well point
systems, deep well pumping, or other ground water interception systems
may also be feasible. In any case, the intercepted leachate is col-
lected, stored, treated (if necessary), and removed. Leachate removal
may be through evaporation, or discharge to a sewage treatment system.
With adequate treatment the collected leachate may be used to irrigate
site vegetation or discharged into surface waters under NPDES permit.
9-3
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Which design alternative is best for any specific new project is depen-
dent on site-specific factors, such as:
Climate, which affects timing of sludge application, and hence
sludge storage required, crops (if any) which can be grown,
etc.
« Site soil and hydrogeology, which affect the extent of ground
water leachate control needed, soil surface preparation,
method of sludge application, crops (if any) which can be
grown, amount of runoff, etc.
Site size and topography, which affect sludge application
rates, feasibility of constructing large storage lagoons,
method of sludge application, runoff control, size of buffer
zone, etc.
t Availability of a sewerage system, which can be used for con-
trolled disposal of surface runoff and/or leachate.
9.5- Site Investigations
Chapters 4 and 5 discussed the procedures and data necessary in the site
selection and evaluation process. Because a OLD site is normally a
long-term operation, sludge application rates are high, and since con-
tainment of sludge contaminants is necessary, the designer is often re-
quired to conduct more extensive site investigations than are necessary
for agriculture and other types of applications.
Ideally, the area selected for the dedicated disposal site would:
Be near the treatment pi ant(s) so as to reduce sludge trans-
port costs.
Have easy transport (e.g., road, pipeline, etc.) access.
Be underlain with an impervious geological barrier, e.g., bed-
rock, continuous thick clay layer, etc, or be underlain with
an exempted aquifer, i.e., an aquifer which is useless because
of existing poor water quality.
Have a large buffer area interspersed between it and areas of
public dwellings, public use areas, etc.
Be distant from surface waters, e.g., lakes, ponds, rivers,
streams, etc.
t Have gentle slopes (e.g., <3 percent) to minimize site grad-
ing, and other improvement costs.
* Be in an area of temperate, arid climate with high net evapo-
ration.
9-5
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Have convenient access to an existing sewer system for con-
trolled discharge of collected surface runoff and/or leachate.
Have heterogeneous soil with adequate drainage permeability,
high cation exchange capacity (CEC), and pH of above 6.5.
As a minimum, the designer will require the following data:
t Climate history, e.g., precipitation (annual, monthly, maximum
year storms, number of days with rainfall above 0.3 cm (0.1
in), evaporation (annual, monthly), and temperatures (number
of days below freezing). See Section 4.7 for discussion of
sources of climate data.
Sludge data, present and future, i.e., quantity, physical
characteristics, chemical characteristics, transport method,
etc.
Topography of the site and surrounding area, i.e., slopes,
surface waters (streams, ponds, etc.), roads, wells, struc-
tures, improvements, drainage, flooding potential, existing
vegetation, etc.
Soil properties of the site, physical and chemical.
Hydrogeological properties, i.e., depth to ground water, depth
to aquifers, quality and use of ground water, ground water
flow direction, existence of impermeable or low permeability
layers (e.g., bedrock, clay).
Site ownership, land use zoning, restrictions, etc.
All of the above site investigation data are discussed in detail in
Chapters 4 and 5. Table 9-2 lists typical siting criteria for a OLD
site.
9.6 Environmental Constraints in Dedicated Land Disposal Site Design
9.6.1 General
Various potential contaminants in sludge are discussed in Appendix A.
The interaction of these contaminants with soil and their fate in the
environment are discussed in Appendix B. The principal potential con-
taminants of concern are excess nitrogen (in the nitrate form), heavy
metals, persistant organics, and pathogens. By definition, it is the
intent of the OLD site to contain these contaminants within the site or
manage their movement off-site in a controlled, environmentally accept-
able manner. Therefore, virtually all state regulatory agencies in 1982
considered proposed OLD projects on a case by case basis. Regulations
for agricultural utilization and other "beneficial" uses of sludge are
9-6
-------
generally not applicable to OLD sites. Restrictions on the use and man-
agement of OLD sites are generally more severe than for "beneficial"
uses. The proponents must demonstrate that the design and management of
the project provides the necessary safeguards.
TABLE 9-2
SITING CRITERIA FOR DEDICATED LAND DISPOSAL
Parameter Unacceptable Condition"
Slope Deep gullies, slope >12%
Soil Permeability >1 x 10"5 cm/sec"1"
<0.6 ra (2 ft) in-situ thickness
Surface Water <92 m (300 ft) to any pond or lake
(distance to) used for recreational or livestock
purposes, or any surface water
body officially classified under
state law
In special flood hazard areas or
recognized wetlands
Ground Water <3.1 ra (10 ft) to ground water
table (wel^s tapping shallow
aquifers)
Wells Water supply wells within 305 m
(potable) (1,000 ft) radius
Ideal Conditions
<3%*
_< 1 x 10"7 cm/sec*
>3ra (10 ft) in-situ
thickness
>305 m (1,000 ft) from any
surface water body
>61 ra (200 ft) from inter-
mittent streams
>15.3 ra (50 ft) to ground
water table
No wells within 610 m
(2,000 ft) radius
* Ideal slope depends on solid content (TSS) and sludge application method.
See Table 5-1 for general slope limitations.
t Pervious soil can be used for DLO if appropriate engineering design pre-
venting OLD leachate from reaching the ground water is feasible.
# When low-permeable soils are too close to the surface, liquid disposal
operation can be hindered due to water ponding.
** If an exempted aquifer underlies the site, poor quality leachate may be
permitted to enter ground water.
9.6.2 Nitrogen Control at Dedicated Land Disposal Sites
One of the keys to an acceptable OLD site is control of nitrates to pre-
vent contamination of ground water aquifers. The possibilities are:
1. There is no useful ground water aquifer below the site which
can be affected; either the aquifer(s) is exempt (of such poor
quality that it is not subject to non-degradation regulations)
or none exists at potentially useful elevations.
, 2. The local climate is arid with a high net evaporation, and use-
ful aquifers are deep. For example, at the OLD site used by
9-7
-------
3.
4.
5.
Denver, Colorado, it was found that precipitation, which aver-
ages 36 cm (14 in) annually, is insufficient to percolate to
any significant depth, and potable water is from 100 to 300 m
(330 to 980 ft) below the ground surface.
An impervious geological barrier, e.g., bedrock or thick clay,
lies between the OLD site and the useful aquifer effectively
preventing significant volumes of leachate from percolating
into the aquifer.
A below ground leachate interception system is constructed,
e.g., drain tiles, well points, etc., which collect the leach-
ate before it can percolate into the aquifer.
It can be shown that the volume
reaching the aquifer is such a
water aquifer flow volume that
gible.
of leachate containing nitrates
small percentage of the ground
potential degradation is negli-
If none of the above possibilities is feasible, singly or in combina-
tion, then a OLD site will probably not be feasible.
9.6.3 Sludge Metals at Dedicated Land Disposal Sites
The safeguards discussed in Section 9.6.2 for protection of ground water
for nitrate contamination will serve for metals also. The long-term ac-
cumulation of metals on a OLD site will eventually have an adverse ef-
fect on most crops.
9.6.4 Sludge Pathogens at Dedicated Land Disposal Sites
Ground water protection measures described in Section 9.6.2 should ade-
quately contain pathogens also. A OLD site is designed to prevent sur-
face runoff so there is no potential contamination from this source
either. Vectors (flies, rodents, etc.) control is needed to prevent
off-site migration and on-site breeding. Adequate buffer zones will
control aerosols and odor complaints. Control of public access to the
site is essential.
9.6.5 Persistent Organics Control at Dedicated Land Dis-
posal Sites
As discussed in Appendix A, most sludges contain only low concentrations
of persistant organics. Further, persistent organics contained in
sludge are generally not very mobile in soil, e.g., they are adsorbed in
the upper soil layers. Therefore, unless the sludge is unusually high
in toxic persistent organic compound concentrations and the site soil is
very permeable (e.g., sand) and leachate controls are not adequate, the
containment of persistent organics within the site should be readily
achieved.
9-8
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9.6.6 Aesthetics at Dedicated Land Disposal Sites
The major aesthetic concern
sludge application sites is
at most OLD
discussed in
sites is odor.
Chapter 11.
Odor control at
Basically, odor problems from sludge are always the result of anaerobic
(septic), conditions. When applying large quantities of liquid sludge,
the soil should be maintained in an aerated condition via surface drain-
age (no ponding), subsurface drainage, and/or tillage (if necessary).
Subsurface injection by sludge application vehicle(s) provides another
alternative to reduce odors.
Liquid sludge storage lagoons are a potential source of odor. If the
sludge is well stabilized, odor problems are usually infrequent, but may
occur (e.g., during a spring thaw after extended cold weather, or during
a major disturbance of the sludge lagoon as would occur during bottom
sediment cleanout). Typical attempts at controlling odors from sludge
lagoons involve (1) locating the sludge lagoon in the OLD site as far
from public access areas as possible, (2) providing as large a buffer
area around the site as possible, and (3) adding lime to the lagoon.
Use of a facultative lagoon (see Chapter 10)., if properly designed, will
reduce the potential for odors. Obviously, if the POTW sludge treatment
process is having problems, e.g., a sour digester, the resulting poorly
stablized sludge should, if possible, not be added to the OLD site stor-
age lagoon.
Dust and noise may result from use of heavy equipment (e,
subsurface injector vehicles, etc.) at sludge application,
agricultural area dust and noise should be no worse than
normal farming operations, and should create no problems.
area, use of buffer zones and vegetative screening (trees,
around the site) may be necessary to mitigate public impact,
g., tractors,
sites. In an
expected from
In an urban
shrubs, etc.,
Table
site.
9-3 lists criteria adapted at the Sacramento, California, OLD
9.7 Preliminary Design of Dedicated Land Disposal Sites
9.7.1 General
Chapter 10 of this manual covers design of many of the facilities and
improvements involved in a OLD site, e.g., clearing, grading, roads,
fencing, buildings, lights, storage facilities, surface water drainage,
etc. This section covers those aspects which are of special importance
to OLD sites. . ,
9-9-
-------
TABLE 9-3
ODOR, DUST, AND HAZARD DISTANCE CRITERIA ADOPTED FOR
THE SACRAMENTO, CALIFORNIA, OLD SITE (4)
Regional Plant
Process Unit
Sludge storage basins
Dedicated land disposal
Ash disposal (grit and
Screening Emergency
Disposal)
Potential for Adverse Effect
Odor potential Is significant.
After studies and mitigation
measures it appears that these
units can meet the criteria in
all but a few instances each
year.
Odor measurements on subsurface
injection show minimal odors.
Surface spreading and subsequent
incorporation would have some
odor potential. Also, infre-
quent summer rain could cause
odor. There is slight poten-
tial for dust, less than typi-
cal farming operations.
Slight odor from grit and
screenings disposal. Dust
will be generated from land-
fill-type disposal operation.
Distance Criteria Used
610 m (2,000 ft)
305 m (1,000 ft) due to
dust, slight odor po-
tential, and acciden-
tial spillage of sludge
on land surface.
610 m (2,000 ft)
Note: Two odor units at site boundary or fence line under maximum conditions is the
basic odor criteria used. Distances have beep developed through the
following:
Odor potential of source.
Mitigation potential.
Case histories in other locations.
Distance availability.
9.7.2 Climate Considerations
Climate is particularly important in the design of dedicated land dis-
posal sites. The designer should obtain the following historical infor-
mation for the past 20 years:
1. Precipitation, by month and year, average and maximum.
2. Twenty-five year storm intensity; also 50 and 100 year storms.
3. Evaporation rate from water surface, by month and year, average
and minimum.
4. Annual number of days of precipitation over 0.3 cm (0.1 in),
average and maximum.
5. Annual number of days below freezing, average and maximum.
See Section 4.6 in Chapter 4 for climate information services.
9-10
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In addition, it is useful to know the local evaporation rate from soils
(usually about 70 percent of that from water surfaces) and evapotranspi-
ration rate estimated from the types of local vegetation (if any) being
considered for planting on the site. This information may be available
from local university agricultural extension services, or federal assis-
tance agencies.
The climate information listed above is used in many aspects of the site
design including:
Designing surface runoff collection, storage, and control
structures.
« Determining necessary sludge storage capacity.
t Determining the area requirements for sludge spreading.
Determining any necessary leachate collection and storage sys-
tems.
Figure 9-2 depicts the major pathways for water entering a project which
the designer should attempt to quantify in design of a OLD site.
9.7.3 Vegetation Considerations at Dedicated Land Disposal
Sites
Table 9-4 presents the major advantages and disadvantages of growing
vegetation on a OLD site. OLD sites surveyed during preparation of this
manual were about equally divided between bare land operation and use of
vegetation.
9.7.4 Surface Runoff Storage Volume Required
OLD sites usually require that storage be provided for surface runoff
resulting from precipitation. Figure 9-3 illustrates various alterna-
tives for disposing of surface runoff. These can range from disposal by
evaporation only in an arid area such as Arizona, to combined disposal
by evaporation, controlled discharge, and return for reapplication to
the site, such as is practiced at the Fulton County, Illinois, site
which receives sludge from the city of Chicago.
It is beyond the scope of this manual to develop all the hydrological
calculations which may enter into making an accurate assessment of the
maximum runoff which can be expected from a specific site. An experi-
enced hydrological designer is necessary and should develop curves for a
maximum precipitation year which plot precipitation, runoff, evapora-
tion, etc., for the site area. Based upon the curves, an estimate can
be made of the runoff storage volume and surface area needed.
9-11
-------
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TABLE 9-4
ADVANTAGES AND DISADVANTAGES OF GROWING VEGETATION
ON DEDICATED LAND DISPOSAL SITES
A. Advantages
1. If surface soil is "tight" and drains poorly, the plant root structure
may improve soil drainage.
2. Plants will enhance water removal through evapotranspiration.
3. Plants will help to reduce surface runoff volume from precipitation.
4. Plants will take up a portion of the nitrogen, metals, and other
sludge constituents applied by incorporating them during growth. If
the plants are harvested and used or disposed in a controlled manner,
the constituents incorporated in the plants are removed from the site.
6. The OLD site will more closely resemble a normal farming operation and
be more visually pleasing to the public.
7. Some of the sludge nutrients will be recycled into vegetation and may
serve as a positive public relations factor to many citizens.
. 8. Harvesting of the plants and their sale may provide a monetary return.
B. Disadvantages
1. Sludge application scheduling is more complex since it usually must
operate around the seeding, cultivation, and harvesting operations.
Planted areas may be "off limits" for high rate sludge application
during many months, often the best months for sludge application from
an operations viewpoint.
2. Planting, cultivation, and harvesting of plants can be labor and
equipment intensive. Capital equipment and operating costs are in-
creased over those for a OLD site which does not grow and harvest
vegetation. Management is more complex since agronomic considerations
are added to the primary mission of sludge management.
3. The area required for sludge application site may be larger with vege-
tation involvement than for a project with no vegetation.
4. Planted areas attract animals which could become a nuisance or serve
as vectors.
5. Planted areas may result in more unauthorized public entry, e.g.,
children climbing fences.
6. Harvested plants may contain metal concentrations too high for human
or animal consumption necessitating controlled disposal.
7. After years of heavy sludge application, the soil may become phyto-
toxic to plants effectively ending any potential for agricultural
operations at the sita.
9-13
-------
EVAPORATION
t
SITE
SURFACE
RUNOFF
LAGOON
CASE 1 - SURFACE RUNOFF DISPOSAL BY EVAPORATION
FROM LAGOON SURFACE ONLY.
EVAPORATION
t
SITE
SURFACE
RUNOFF
LAGOON
RETURN FLOW FOR APPLICATION TO SITE
CASE 2 -
SURFACE RUNOFF DISPOSAL BY EVAPORATION
FROM LAGOON TO SURFACE PLUS RETURN OF
STORED RUNOFF TO THE SITE FOR APPLICATION.
EVAPORATION
t
SITE
SURFACE
RUNOFF
LAGOON
CONTROLLED
DISCHARGE *"
HFF STTF
CASE 3 - SURFACE RUNOFF DISPOSAL BY EVAPORATION FROM
LAGOON SURFACE PLUS CONTROLLED DISCHARGE
FROM LAGOON TO SURFACE WATER, SEWER, ETC.
EVAPORATION
SITE
SURFACE
RUNOFF
LAGOON
CONTROLLED
RETURN FLOW FOR APPLICATION TO SITE
DISCHARGE
OFF SITE
CASE 4 - COMBINATION OF CASE 2 AND CASE 3 ABOVE
Figure 9-3.
Alternate considerations for disposal of surface
run-off stored in lagoons.
9-14
-------
The hydrologic
his design:
designer will typically use the following information in
Area of the site. ,
t Historical precipitation records; normally the designer se-
lects the "wettest" period expected over a period of years
(possibly 10, 25, 50, or 100 years), depending upon the degree
of safety desired. The degree of safety desired or required
by local regulatory officials will vary for particular sites,
depending on the economics associated with increased safety
and the potential for environmental damage that would be
caused by an overflow of the storage lagoon.
Site runoff; a function of soil type, infiltration, amount of
previous recent precipitation, soil moisture retention, and
vegetation (if any) at the site.
t Evaporation; from the lagoon surface and the soil surface. If
vegetation is present, then evapotranspiration is also a fac-
tor.
Controlled discharge or expected seepage, if any, from the
storage lagoon.
9.7.5 Sludge Application Rate Calculations
9.7.5.1 General
Unlike agricultural and forest sludge application options, the applica-
tion rate of sludge to dedicated disposal sites (as defined in this man-
ual) is not limited by plant uptake (nitrogen fertilizer) and cumulative
metal totals, but is limited by the following factors:
The rate of sludge which can be applied during each applica-
tion while still maintaining aerobic conditions in the soil.
The method of sludge application, soil drainage, soil charac-
teristics, sludge moisture content, and climatic conditions
all influence this factor.
The number of days during the year when sludge can be applied
as dictated by weather conditions, ability of the sludge ap-
plication equipment to operate with existing soil conditions,
any vegetation planting/harvest, etc., restrictions (if vege-
tation is grown on the site), and equipment breakdown and
maintenance requirements.
Evaporation
liquids.
rates if that is the design, pathway for sludge
9-15
-------
9.7.5.2 Sludge Application Rates
Annual sludge application rates to OLD sites reviewed during preparation
of this manual ranged from 12 dry rot/ha (5 T/ac) up to 2,250 dry mt/ha
(1,000 T/ac). The higher application rates are practiced at OLD sites
which:
Receive dewatered sludge.
t Mechanically incorporate the sludge into the soil.
Have relatively low precipitation.
Are not faced with leachate contamination of ground water
problems because of site conditions or project design.
A conservative approach is to match sludge application and net soil eva-
poration rates. Sludge application is intensive during warm and dry
periods, and reduced during wet or cold periods.
Net soil evaporation is calculated by the use of:
EN = ES - P
(9-1)
EN = (f x E, ) - P
(9-2)
where:
EM = net soil evaporation
£5 = gross soil evaporation
EL = gross lake evaporation
P = precipitation
f = factor expressing the relationship of soil and lake
evaporation (dimensionless).
Typically, gross soil evaporation in an area is estimated as a fraction
(e.g., f = 0.70) of the lake evaporation. Estimates can be obtained
from local agricultural information services. Table 9-5 illustrates the
calculation of net soil evaporation on a monthly basis for Colorado
Springs, Colorado (9).
9-16
-------
TABLE 9-5
NET MONTHLY SOIL EVAPORATION AT COLORADO
SPRINGS, COLORADO (9)
Gross Soil
Month Evaporation (era)*
January
February
March
April
May
June
July
August
September
October
November
December
.
-
_
9.16
11.45
13.55
14.69
12.43
9.58
7.34
_
-
Precipitation (cm)
1.80
1.85
3.96
4.85
5.44
5.49
7.62
5.89
3.94
2.82
2.41
1.70
Net Soil
Evaporation (cm)
_
-
-
4.31
6.01
8.06
7.07
6.54
5.64
4.52
-
-
Annual
78.20
47.78
42.15
* Estimated based on 70 percent lake evaporation.
t Gross soil evaporation less precipitation.
# 1 in = 2.54 cm.
Having estimated net soil evaporation
application rates on a monthly basis
moisture in the applied sludge against
(EN)
are
for each month, the sludge
calculated by matching the
as shown in Equation (9-3):
LN x TS x C
KM 100 - TS
(9-3)
where:
RM = monthly sludge application rate (dry mt/ha/mo) or (dry
T/ac/mo).
EN = net soil evaporation (cm/mo) or (in/mo)
TS = total solids content of the sludge (%) by weight
C = a conversion factor which equals 100 mt/cm in metric
units or 113.3 T/in in English units.
Table 9-6 shows monthly sludge application rates for the Colorado
Springs, Colorado, site, based on a sludge with 4.85 percent solids con-
tent and the net monthly soil evaporation rates shown in Table 9-5.
Sample calculations for April are:
Engl1sh
1.70 x
- 9.8 T/ac
9-17
-------
TABLE 9-6
MONTHLY SLUDGE APPLICATION RATES AT
COLORADO SPRINGS, COLORADO, OLD SITE (9)
Month
January
February
March
Apn'1
May
June
July
August
September
October
November
December
Annual
Monthly Application Rate
(dry rat/ha)1" (dry T/ac)f
22.0
30.7
41.1
36.1
33.4
28.8
23.1
215.0
9.8
13.7
18.3
16.1
14.8
12.8
10.3
95.8
* Total solid content in the sludge is assumed to be 4.85
percent.
t Using Equation (9-3) and data from Table 9-5.
Refering to Table 9-6, an annual average total of 215 mt/ha (95.8 T/ac)
dry weight of sludge could be applied at this site using net soil evapo-
ration as a basis.
The use of net soil evaporation as a basis for calculating sludge appli-
cation rates is obviously conservative since it makes no allowance for
moisture removal from the sludge through infiltration into the soil. If
infiltration is allowed, sludge application rates can be calculated by
the following equation:
R -
RM ~
+ I) x TS x C
100 - TS
(9-4)
where:
I = infiltration rate (cm/mo) or (in/mo), and all other terms are
the same as in Equation (9-3).
9.7.5.3 Drying Period Between Sludge Applications
Drying (rest) periods between sludge applications allow the soil to re-
turn to its natural aerobic condition. Applications should be scheduled
to prevent excessive moisture in the soil for long periods, and to mini-
mize odors and the breeding of vectors.
9-18
-------
It is difficult to provide exact guidelines for the length of the drying
period because so many factors are involved, e.g.:
Quantity and moisture content of sludge applied.
Method of sludge application.
« Net soil evaporation rate and precipitation occurring during
the days following application.
Soil texture and infiltration rate.
Generally, if dewatered sludge is applied and/or the sludge is incorpo-
rated into the soil during application, drying periods between applica-
tions can be short, e.g., 2 to 3 days, providing the weather is favor-
able. When liquid sludge is applied to the soil surface without soil
incorporation, the drying periods between application should be longer
(e.g., 5 to 20 days), depending upon the quantity applied, topography,
soil properties, and the weather. Figure 9-4 shows suggested periods
between sludge applications ,as a function of the type of sludge (liquid
or dewatered), whether the sludge is incorporated into the soil, and ap-
plication rate. Figure 9-4 is based on experience at a limited number
of OLD sites reviewed and is provided for general guidance only.
Aerobic conditions in the soil are more easily maintained by lighter ap-
plications of sludge at more frequent intervals. For example, refering
to the upper curve in Figure 9-4 for liquid sludge, not incorporated
into the soil, application of 11 mt/ha (5 T/ac) at 7-day intervals is
generally preferable to the application of 31 mt/ha (14 T/ac) at 20-day
intervals. The heavier sludge application is more likely to cause an-
aerobic soil conditions conclusive to odors and vector breeding.
9.7.6 Land Area Requirements
9.7.6.1 General
Land area requirements for a OLD site comprise the total land needed for
sludge disposal, sludge storage, buffer areas, surface runoff control,
and supporting facilities. In the following subsections each of these
needs is discussed. The prudent designer will incorporate appropriate
safety factors into the design to allow for necessary future expansion,
and additional facilities.
9.7.6.2 Land Area Requirement for Sludge Disposal
As discussed in Section 9.6.2, acceptable sludge application rates to
OLD sites are highly variable depending on sludge characteristics, cli-
mate, soil characteristics, and other site specific factors. When the
annual sludge application rate has been determined, it is a simple cal-
culation to divide this rate into the present and future estimated
9-19
-------
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9-20
-------
quantity of sludge which must be disposed in order to calculate the
sludge disposal area required, as shown below:
Area required =
Maximum annual design sludge generation in dry weight
Annual application rate in dry weight/unit area
9.7.6.3 Land Area Requirement for Sludge Storage
Design of sludge storage facilities is discussed in Chapter 10. Sludge
storage is virtually always required because adverse weather or other
factors prevent the continuous application of sludge to the OLD site.
Storage may be located at the POTW, at the OLD site, or both. As a min-
imum, the sludge storage facilities should have sufficient capacity to
retain all sludge generated during nonapplication periods. Liquid
sludge is typically stored in lined lagoons or metal tanks. Dewatered
sludge is typically stored by mounding in areas protected from runoff.
Calculation of the volume required for liquid sludge storage is detailed
in Chapter 10. The procedure takes into account volume of sludge gen-
erated, precipitation, evaporation, and other pertinent factors. Often
the regulatory agency will stipulate a required sludge storage volume
which reflects a time period, e.g., one month storage, two month stor-
age, etc.
In any case, once the necessary storage volume has been established, the
land area required for either liquid sludge lagoons or dewatered sludge
stockpiles can be determined, based on depth, height, freeboard, berm
construction area, etc. As a rough approximation, the land area re-
quired equals three times the volume of the sludge to be stored divided
by the depth (or height) of the material stored. For example, assume
that one million L (35,310 ft3) of liquid sludge storage is required and
the liquid depth of the lagoon is 3 m (9.8 ft). Approximate area re-
quired equals 1,000 m2 (10,800 ft^).
9.7.6.4 Land Area Requirement for Surface Runoff Capture
and Storage
Storage lagoon design is discussed in Chapter 10.
Once the required storage volume has been determined (Section 9.7.4),
the necessary land area can be easily calculated based on lagoon depth,
freeboard, and berm construction. As noted in Section 9.7.6.3, a rough
approximation of land area required can be derived by multiplying by
three the volume of the runoff to be stored, and dividing by the depth
of the lagoon.
The land area required for surface runoff collection, e.g., drainage
ditches, etc., is normally only a small percentage of the total OLD site
area (e.g., 2 to 5 percent).
9-21
-------
9.7.6.5 Land Area Required for Buffer Zone
The desired width of an acceptable buffer zone will vary, depending upon
surrounding land use, and the potential for odor, dust, noise, etc., re-
sulting from site design and operation.
A minimum buffer of 150 m (500 ft) is suggested around any OLD site. A
minimum buffer of 600 m (2,000 ft) is suggested around OLD sites when
one or more of the following conditions will exist:
§ Liquid sludge is stored at the site in open lagoons.
During application liquid sludge is spread on the soil surface
and not quickly incorporated by disking.
During application liquid sludge is sprayed by use of a wide
coverage spray device(s).
t Residential dwellings or other heavy public use areas are ad-
jacent to the OLD site.
t Sludge application rates are heavy and it is anticipated that
anaerobic soil conditions will periodically result.
While difficult to quantify, the desirable width of a buffer zone is
also a function of the size of the operation, e.g., volume of sludge
disposed, application area, etc. The larger the operation the more buf-
fer area is desirable simply because the magnitude of potential nuisance
to surrounding property is greater.
9.7.6.6 Land Area Required for Supporting Facilities
Support facilities may include roads, buildings, etc. Compared to other
land area requirements previously discussed, the area for these facili-
ties is usually very small, e.g., less than 3 percent of the OLD site
total.
9.7.7 Ground Water Leachate Collection and Control
As discussed in Section 9.5, the ideal location for a OLD site is one
where ground water contamination from leachate is of no concern because
of favorable site conditions. However, if the OLD site is located where
it could contaminate potable ground water aquifers, the designer must
consider means to intercept the percolating leachate.
Subsurface drainage systems may be needed when natural drainage is re-
stricted by relatively impermeable layers in the soil profile near the
soil surface, or by high ground water. As a result of the restrictive
layer, shallow ground water tables can extend close to the soil surface.
Such a high ground water table may create serious problems in sludge ap-
plication because of ponding, anaerobic soil conditions, and muddy sur-
faces.
9-22
-------
Buried plastic pipe or clay tile,-10 to 20 cm (4 to 8 in) diameter, are
normally used for underdrains. Concrete pipe is less suitable because
of the sulphates in leachate from sludge amended soils. Underdrains are
normally buried 1.8 to 2.4 m (6 to 8 ft) deep, but can be as deep as 3 m
(10 ft) or as shallow as 1m (3 ft). Spacing of drains typically range
from 15 m (50 ft) in clayey soils up to 120 m (400 ft) in sandy soils.
Procedures for determining the proper depth.and spacing of drain liner
are found in Section 5.7 of "The Process Design Manual for Land Treat-
ment of Municipal Wastewater," EPA, October 1981 (17), and in References
(18) and (19).
If a subsurface drainage collection system is installed beneath the OLD
site, the leachate collected from the system must be treated, stored,
and/or disposed of. Alternatives for disposal were shown in Figure 9-1.
9.8 Methods for Application of Sludge to Dedicated Land Disposal Sites
9.8.1 General
The designer has a number of alternatives in selecting the method of ap-
plying the sludge to the soil. These are:
Subsurface application of liquid sludge.
Surface application of liquid sludge.
Application of dewatered sludge.
A detailed explanation of sludge application methods is found in Chapter
10 of this manual.
9.8.2 Application of Liquid Sludge
Liquid sludge can be applied either by surface spreading or subsurface
injection methods. The latter is often more desirable since it mini-
mizes potential odor and runoff problems.
Surface spreading of liquid sludge, or flooding without subsequent in-
corporation, is less expensive than subsurface injection in terms of
equipment and labor. However, the dedicated land disposal sites re-
viewed during preparation of this manual had experienced problems when
using surface spreading methods. Difficulties that may be encountered
with the method include odors, uneven distribution of sludge, clogging
of soil surface, and difficult vehicle access into the area.
9.8.3 Application of Dewatered Sludge
The application of dewatered sludge (20 percent solids or more) is simi-
lar to that of solid or semisolid fertilizer, lime, or animal manure.
Sludge can be spread with bulldozers, front end loaders, graders, or box
spreaders, and then incorporated by plowing or disking. The spiked
tooth harrows used for normal farming operations may be too light to
bury sludge adequately and heavy-duty mine disks or disk harrows may be
required.
9-23
-------
9.9 Monitoring Requirements
9.9.1. Criteria Pertaining to Water Resource Protection
Regulations promulgated under Sections 1008(a)(3) and 4004(a) of the Re-
source Conservation Recovery Act, and Section 405(d) of the Clean Water
Act, require the following standards for ground and surface waters for
all solid waste disposal facilities and practices (12):
Ground Hater Standards: A facility or practice must not contaminate an
underground drinking water source beyond the waste site boundary or be-
yond an alternative boundary specified by the state which has an EPA-
approved solid waste management plan.
Surface Water Standards; A facility or practice must not:
Violate the requirements of the National Pollutant Discharge
Elimination System (NPDES).
Cause a discharge of dredged material or fill material to wat-
ers of the United States.
Cause non-point source pollution of waters of the United
States or border bodies of water.
9.9.2 Monitoring Needs
A OLD system should be designed in such a manner that it will not con-
taminate surface and ground water sources. Monitoring programs should
basically be designed to insure that the OLD system functions as in-
tended. Chapter 11 of this manual discusses monitoring requirements for
various types of sludge to land treatment alternatives. In general,
monitoring requirements for dedicated land disposal sites are more ex-
tensive than for other types of sludge land application options, and may
include:
Monitoring of applied sludge quantities and characteristics.
Monitoring of changes in site soil characteristics, physical
and chemical.
Monitoring of ground water quality beneath the site and adja-
cent to the site in the direction of ground water flow; moni-
toring of both saturated and unsaturated zones, and at various
depths may be required.
i
Monitoring of surface water runoff from the site.
Monitoring of surface waters potentially affected by the site.
Monitoring of odor, dust, and/or aerosol emissions from the
site.
9-24
-------
9.9.3 Closure and Post-Closure Care Plans
Closure and post-closure plans of a retired OLD site' may be the last
phase of waste management at the site. Acceptable closure practices are
generally similar to those of landfills (12) and should be:
t Technologically sound with respect to protection of local
water resources. '
e Compatible with the projected future use of .the site (i.e.,
golf course, park, parking Tot, etc.).
The designer should identify any post-closure requirements of the re-
sponsible regulatory agency in the area where the OLD site is located.
9.10 Design Example
The design example is for a community of 400,000 located in Central
California. A specific site has been tentatively selected, cognizant
regulatory agencies have been contacted, and a public participation pro-
gram initiated.
The existing POTW utilizes a conventional activated sludge process which
generates a mixture of primary and waste activated sludge. The sludge
is anaerobically digested. Approximately 25 percent of the wastewater
treated is from industry, primarily seasonal food processing wastewat-
ers.
9.10.1 Sludge Generation and Characteristics
Table 9-7 projects sludge production from 1980 through 1999. Table 9-8
shows characteristics of the sludge.
9.10.2 Climate
Average climatological data for the area is presented in Table 9-9.
Evaporation is recorded at locations 17 miles to the east, and 12 miles
to the west. High daytime temperatures and low humidity in the summer
account for the pronounced evaporation rates. Average annual rainfall
is 42 cm (17 in), but varies from a minimum of 12 cm (5 in) to a maximum
of 92 cm (36 in) with maximum 1-hour and 24-hour rainfalls recorded at
4.19 cm (1.65 in) and 8.94 cm (3.52 in), respectively.
9.10.3 State and Local Regulations of Concern
The appropriate regulatory agencies have advised that the site would
probably be subject to the following regulations:
Off-site wastewater discharge: none would be preferred. If
necessary to have a discharge, the NPDES permit would stipu-
late essentially drinking water quality.
9-25
-------
TABLE 9-7
PROJECTION OF DIGESTED SLUDGE PRODUCTION
FOR DESIGN EXAMPLE
Year
1980
1985
1992
1999
(Wet) m3/yr
756 x 103
786 x 103
936 x 103
1,007 x 103
Digested Sludge Production
Dry mt/yr M gal/yr
17,000 197.9
18,000^ ' 205.7 . .
22,300 245.0
25,100 263.6
Dry ton/yr
18,700
19,800
24,500
27,600
1
TABLE 9-8
TYPICAL CHARACTERISTICS OF DIGESTED
AND LAGOONED SLUDGE FOR DESIGN EXAMPLE
Constituent
Total solids, %
Volatile solids,
Total nitrogen, ;
Phosphorus, %
Arsenic, mg/kg
Cadmium, mg/kg
Chromium, mg/kg
Copper, mg/kg
Lead, mg/kg
Mercury, mg/kg
Nickel, mg/kg
Selenium, mg/kg
Silver, mg/kg
Zinc, mg/kg
Concentration
2.68
% , 1.54
I 7.5
2.5
6-13
27-51
52-213
280-560
96-210
11-16
72-193
3-9 ,,
7-14
1,080-1,723
*
* All concentrations are exressed on a dry weight basis.
9-26
-------
Ground water leachate percolation: None would be preferred.
If necessary to have leachate, monitoring is required to en-
sure that ground water at the project boundary meets drinking
water standards.
Flood control facilities heed to protect against site flooding
by the maximum 100-year storm.
Sludge must be incorporated into soil during or immediately
after sludge application to prevent/minimize odors.
A minimum of 3 months of sludge storage capacity must be pro-
vided* If sludge storage is in open ponds, a minimum distance
of 610 m (2,000 ft)
ponds to the nearest
must be provided
site boundary.
from the sludge storage
9.10.4 Characteristics of the Site
The area selected for the OLD site has flat topography with a maximum
elevation difference of 6 m (20 ft) within the 240 ha (600 ac) investi-
gated. The surrounding area is predominantly farm land.
Results of soil borings are shown in Table 9-10. While this is obvi-
ously a simplified version of an extensive soils report, the summary
notes that the upper 3 to 6 m (10-20 ft) of the site consist of soils of
very low permeability, including a central layer with permeability of 1
x 10~9 cm/sec, or less, which appears continuous at depths of 3 to 6 m
(9 to 20 ft). The free ground water is confined below this layer, which
provides an essentially impermeable barrier to, downward migration of
surface leachate. Soil is dense and slowly permeable.
9.10.5 Determination of Sludge Application Rates
For this design example sludge application rates will be estimated based
upon positive net soil evaporation rates, as was discussed in Section
9.6.2. It may be preferable to conduct tests on experimental plots for
several years to determine more optimum sludge application rates.
Table 9-11 shows the monthly net soil evaporation rate for the area.
Table 9-12 shows the monthly sludge application rate based upon Equation
(9-3):
EN x TS x C
KM 100 - TS
presented in Section 9.6.2. An example calculation for the month of May
follows:
(Metric) RM
(English) Rh
13.17 x 2.68 x 100
(100) - (2.68)
5.19 x 2.68 x 113
" (100) - (2.68)
36.3 mt/ha/mo
16.1 T/ac/mo
9-27
-------
TABLE 9-9
AVERAGE CLIMATOLOGICAL DATA FOR THE SLUDGE
APPLICATION AREA FOR DESIGN EXAMPLE
Month
January
February
March
April
May
June
July
August
September
October
November
December
Annual
Air
(°C)
7.3
9.6
11.9
14.7
17.8
21.4
24.1
23.4
22.0
17.5
10.5
8.0
-
Temperature
(°F)
45.2
49.2
53.4
53.4
64.0
70.5
75.4
74.1
71.6
63.5
50.9
46.4
-
Precipitation
(cm)*
8.08
7.59
5.99
3.56
1.50
0.25
0
0.05
0.48
1.96
4.58'
8.23
42.24
Evaporation
Low
2.24
3.73
8.18
12.98
20.96
24.28
27.99
25.07
19.08
11.63
4.45
2.29
162.88
(cm)
High
4.52
5.77
12.27
19.66
28.35
32.39
33.43
29.49
24.03
16.23
6.60
3.86
216.46
* Long-term average data.
t Metric conversion 1 cm = 0.
39 in.
TABLE 9-10
SOIL CHARACTERISTICS OF DEDICATED
LAND DISPOSAL SITE FOR DESIGN EXAMPLE*
Depth From Surface
0 - 3 m
(0 - 10 ft)
3 - 6 m
(9 - 20 ft
Dominant Unified
Soil Classification
Silty clays (CL)
Organic clays (OH)
Clayey silts (ML)
Cemented soils in
two layers. Upper
Vertical
Permeability .
cm/sec
1 x 10~J° to
5 x 10"8
1 x 10"9 to
1 x ID'10
6 - 13 M
(19 - 40 ft
layer is silty clay
(CL) and lower layer
is fine sandy silt
(ML) and silty fine
sand (SM)
Clean fine to medium
sands
3 x 10'5 to
1 x 10
,-6
* Ground water surfaces range from 4 to 15 m (13 to 46 ft) below surface.
9-28
-------
TABLE 9-11
NET SOIL EVAPORATION AT DEDICATED LAND
DISPOSAL SITE FOR DESIGN EXAMPLE
Lake
Evaporation
Month (cm*)
January
February
March
April
May
June
July
August
September
October
November
December
Annual
2.24
3.73
8.18
12.98
20.96
24.28
27.99
25.07
19.08
11.63
4.45
2.29
162.88
Soil
Evaporation
(out)
1.57
2.61
5.73
9.09
14.67
17.00
19.59
17.55
13.36
8.14
3.11
1.60
114.02
Precipitation
(cm#)
8.08
7.59
5.99
3.56
1.50
0.25
0.60
0.05
0.48'
1.96
4.58
8.23
42.24
Net Soil Evaporation
cm
(6.51)
(4.98)
(0.26)
5.53
13.17
16.75 '
19.59
17.00 ,
12.88
6.18
(1.47)
(6.63)
71.78
in
(2.56)
(1.96)
(0.10)
2.18
5.19
6.60
7.72
6.70.
5.07
2.43
(0.58)
(2.61)
28.28
* Uses lowest evaporation from Table 9-9.
t Uses 70 percent of lake evaporation.
# Uses average from Table 9-9.
** Metr,irc conversion = 1 cm = 0.39 in.
Based upon this theoretical approach, the annual cumulative sludge ap-
plication rate to the site shown in Table 9-12 is 250 mt/ha (112 T/ac),
dry weight. No sludge would be applied during the "wet" season from
November through March.
Based on an annual sludge application rate (dry weight) of 250 mt/ha
(112 T/ac), and annual sludge generation in 1980 of 17,000 mt/yr (18,700
T/yr) per Table 9-7, a simple division determines that the sludge appli-
cation area required in 1980 is 68 ha (167 ac).
Referring to future estimates of sludge generation shown in Table 9-7,
the sludge application area required increases as follows:
Year
1980
1985
1992
1999
Area Required
Ha Ac
68
72
89
100
167
177
219
247
9-29
-------
TABLE 9-12
MONTHLY SLUDGE APPLICATION RATES FOR DESIGN
EXAMPLE BASED ON NET SOIL EVAPORATION
Net Soil Evaporation*
Monthly Application Rate,
Dry Weight'
Month
January
February
March
April
May
June
July
August
September
October
November
December
Annual
cm
(6.51)
(4.98)
(0.26)
5.53
13.17
16.75
19.59
17.00
12.88
6.18
(1.47)
(6.63)
71.78
in
(2.56) ..
(1.96)
(0.10)
2.18
5.19
6.60
7.72
6.70
5.07
2.43
(0.58)
(2.61)
28.28
mt/ha/rao
_
-
-
15.2
36.3
46.1
53.9
46.8
35.4
17.0
-
-
250.7
T/ac/mo
.
-
-
6.8
16.1
20.5
24.0
20.8
15.8
7.6
-
-
111.6
* From Table 9-11.
t Uses Equation (9-3) in Section 9.6.2:
R = EN x TS x C
H 100 - TS
where:
RM « monthly sludge application rate.
EN = net soil evaporation (from Table 9-11).
TS » total solids content of the sludge, equals 2.68 percent
(Table 9-8).
C « A conversion factor which equals 100 mt/cm in metric
or 113 T/in in English units.
9-30
-------
9.10.6 Sludge Storage For Design Example
Sludge storage volume is required for the period when sludge is not
applied to the site, i.e., the 5-month "wet" season from November
through March. This is 2 months longer than the 3-month storage "re-
quired" by the state. Table 9-13 shows the calculation for required
monthly'Sludge storage. As can be seen in the last column, a sludge
storage volume in 1980 of 283,000 m3 (75 M gal) is required.
TABLE 9-13
CALCULATION OF SLUDGE VOLUME STORAGE NEEDS
FOR 1980 SLUDGE GENERATION FOR DESIGN EXAMPLE
Month
October
November
December
January
February
March
April
May
June
July
August
September
Annual
1980
Wet Sludge
Vol ume*
m3 x 103
63
56
51
50
51
52
57
69
71
80
80
76
756
SI udge
Application
Ratet
(mt/ha/mo)
,17
-
-
-
-
-
15.2
36.3
46.1
53.9
46.8
35.4
250.7
Wet Sludge
Vol ume
Applied*
m3 x 103
51
-
-
-
-
-
46
110
139
163
142
107
758
Change
in
Storage
m3 x 103
12
56
51
50
51
52
11
-41
-68
-83
-62
-31
Cumulative
Storage
m3 x 103
12
68
119
169
220
272
283
242
174
91
29
-2
* Wet sludge volume generated from example city records. Summer increase due
to seasonal food processing industrial wastewater.
t Sludge application rate from Table 9-12.
# Wet sludge volume applied equals sludge application rate in dry metric
ton/ha x application area of 68 ha x 44.5 m3 of wet sludge per metric ton of
dry sludge solids (see Table 9-7).
** Conversion factors: i m3 = 255 gal; one mt/ha/mo = 0.446 T./ac/mo.
9-31
-------
The sludge storage volume required increases proportionately to sludge
volume generated in subsequent years as shown in Table 9-7, as follows:
Year
1980
1985
1992
1999
Sludge Storage Volume Required
m3 x 103 M gal
283
294
350
377
75
78
93
100
This is a preliminary calculation. It is necessary to check the effect
of precipitation and evaporation on the proposed sludge ponds before de-
sign finalization, as shown in the following subsection.
9.10.7 Sludge Storage Design
Design of sludge storage facilities is discussed in Chapter 10. For
this example, the designer decided to provide open storage lagoons with
diked sides and heavy clay lining to prevent seepage. Four lagoons are
provided with a capacity of 94 x 103 m3 (25 million gal) each. Figure
9-5 shows the general arrangement of the four lagoons.
To obtain the final sludge storage volume required for design purposes,
it is necessary to check the effect of evaporation from the liquid
sludge surface and precipitation falling on the liquid sludge surface
and the exposed inside slopes of the containment berms. Seepage is as-
sumed to be negligible. Table 9-14 shows these data. By coincidence,
the necessary final maximum storage volume for 1980 calculated in Table
9-14 is the same as was preliminarily determined in Table 9-13. Had the
precipitation been higher and evaporation lower, as it is in much of the
country, the final storage volume determined would have been greater
than the preliminary calculation in Table 9-13, and the designer would
have had to adjust the sludge pond depth to accommodate the excess pre-
cipitation.
Many considerations other than volume required enter into design of the
sludge storage lagoons, including:
Piping and appurtenance involved in adding and removing
sludge, as well as interconnections between sludge ponds.
Construction of sludge ponds, including lining of wetted por-
tion, erosion control on dike slopes, dike construction, etc.
Number and size of storage ponds.
9-32
-------
A
E
0>
in
ro
k
^ ' . -r
i-OUTSIDE BEAM SLOPE 1 1 m
^ TYPICAL ALL AROUND
+
1
131 X 131
BOTTOM
TYPICAL
>«
»
"-INSIDE DIKE SLOPE 16.5 m
TYPICAL WITHIN EACH 'POND
PLAN VIEW
ACCESS ROAD
3 m TYPICAL
14.1 m TYPICAL
3 m ACCESS ROAD, TYPICAL
L m FREEBOARD
5.5 m INSIDE
DIKE HEIGHT
3.7 m OUTSIDE
DIKE HEIGHT
L 4.6 m SLUDGE
DEPTH
TYPICAL SECTION VIEW
3:1 SLOPE,
ALL DIKES
TYPICAL
Figure 9-5. Sludge storage ponds, conceptual design
9-33
-------
cn
CD
eC
o:
oo
LU
CD
LU
t-H LU
LU
03
01 O LU
> Q
LU
i LU ce.
CO CD O
1 O
oo oo
2= O
O LU
U_
a! ^
r^. «3- o -H ro ro t-H
-< r-. ro cc co CM m
*-« t-< CM C\J CM CM ^-l
CO LO OO
CM C^J CO CO CO
^-1 CM CM CM CM «-<
CO LO CT*
i-H CTt C7> CM
.-t ^3- CM CM CO CO CM
CT* CQ
CM CM CM CM
CM O O O
to co «i
£_ O cr 3 c
Z3 CL ^~ '**
O OJ O »t-
CO X CU X
t_ o t- o cr s- cr
i i i i
c cz cz c
O O O O O O O
9-34
-------
It is assumed that the designer will utilize accepted engineering prac-
tices in preparation of the final storage pond(s) design.
9.10.8 Surface Runoff Control for Design Example
The basic objectives of surface water control design is to minimize the
volume of runoff water which contacts the disposed sludge, and to manage
the runoff water which has contacted the sludge/soil mixture.
Chapter 10 of this manual, and standard hydrological design texts dis-
cuss various methods of surface water drainage control. This design
example will focus on storage and management of the surface runoff which
has contacted the sludge/soil mixture and must be managed in an environ-
mentally exceptable manner.
9.10.8.1 Surface Runoff Storage Volume Required
The stored runoff water will be discharged to a collection sewer which
returns to the POTW. However, the sewer has limited capacity, and it is
necessary to store the runoff and bleed it into the sewer over time.
Design criteria for this case are:
Maximum 100-year storm = 8.94 cm (3.52 in) in 24 hours and
14.48 cm (5.70 in) in 72 hours.
Maximum runoff for the site = 37 percent of precipitation.
t Sludge application area in 1980 = 68 ha (167 ac) and in 1999 =
100 ha (247 ac).
Sewer capacity for discharge of stored runoff = 7,600 m3/day
(2 M gal/day).
For preliminary design purposes, the surface runoff storage volume is
calculated as follows for 1999:
SR = [(P72) x (SA) x (% RD)] - (D72)
where:
SR = Runoff storage required
Maximum 72-hour precipitation
Sludge-amended (application) area
% RD = % runoff from site soil, expressed as a fraction
Quantity which can be bled off to sewer in 72 hours
D
72
9-35
-------
(14.48 cm x * "* x 100 ha x 10,000 m2/ha x 0.37)
JLUU CHI
3
rn
24 hr
gfll
Assuming one rectangular, open basin, with banned side slopes of 3:1 and
effective liquid depth of 3 m (10 ft), the total basin area required is
approximately 1.6 ha (4 ac).
9.10.9 Other On-Site Improvements Area Required
For preliminary design purposes, it is assumed that the land area re-
quirements for other improvements are as follows:
t On-site drainage collection: 3 percent of sludge application
area = 0.03 x 100 ha = 3 ha (7.4 ac).
On-site roads, structures, fencing: 5 percent of sludge ap-
plication area = 0.05 x 100 ha = 5 ha (12.4 ac).
9.10.10 Total Site Area Required
Site area required excluding buffer zone is totaled as followed for the
ultimate design to the year 1999.
Sludge application area = 100 ha (247 ac).
Sludge storage basins = 13 ha (32 ac).
Surface runoff storage basin = 1.6 ha (4 ac).
On-site drainage collection = 3 ha (7.4 ac).
On-site roads, buildings, etc. = 5 ha ( 12.9 ac).
The total site area excluding buffer zone = 122.6 ha (303 ac). However,
the responsible regulatory agency has indicated that a minimum distance
of 610 m (2,000 ft) must be provided from the sludge storage ponds to
the site boundary, and a minimum distance of 305 m (1,000 ft) be pro-
vided from the sludge application area to the site boundary. Assuming a
square site, the minimum total site dimensions, including the buffer
zone, are 1,720 m x 1,720 m (5,642 ft x 5,642 ft) as shown in Figure 9-
6. Total area required is 296 ha (731 ac).
9.10.11 Sludge Application Method
Sludge will be pumped via pipeline from the POTW to the sludge storage
ponds located near the center of the dedicated land disposal site.
Sludge will be applied from May through October. Dredged sludge is
pumped from the sludge storage pond to the application area through a
buried pipeline to field hydrants, and subsequently to flexible hoses
which are connected to subsurface injectors (Figures 9-7 and 9-8).
While dragging the hose, the subsurface injector will traverse the
length of the disposal site, turn 180° at each end, and return in a path
9-36
-------
A
E
o
r-l
1
k
r
^ ~v
A
E
(f>
O
TH
T
k
r
A
c
1
4
E
O\
in
ro
^
k
H09m ^
-.. ^
350 m /
^ k. /
k
r
^ ^
SLUDGE
STORAGE
PONDS
V SLUDGE APPLI
CATION
(^ AREA' PLUS
^ RUNOFF STORA'GE,
DRAINAGE, Po'NDS
AND STRUCTURES
L
>/ 305 . 5 m
TYPICAL
ALL AROUND <<^) ,
^ - / l
k
O
z
D
_J O
< o:
o <
M
0 Q. _|
03 >- _J
VO 1- <
^
-------
SEWAGE
TREATMENT
PLANT
SLUDGE STORAGE
PONDS
^ HYDRANTS LOCATED
IN SLUDGE APPLICATION
AREA (TYPICAL)
FLEXIBLE HOSE CONNECTED TO HYDRANT
TRACTOR AND INJECTION UNIT
Figure 9-7. Schematic diagram of sludge pumping and application
method.
9-38
-------
Figure 9-8. Tractor and injection unit.
9-39
-------
adjacent to the preceding pass. In normal operation, freshly applied
solids remain unexposed to the atmosphere. However, regular disking of
the site will be used to break up the soil/sludge surface and to expose
more of the sludge-soil mixture to the atmosphere to enhance drying and
degradation.
Generally, during June, July, and August, sludge will be removed from
the storage ponds, and applied to the same site twice a week, and in
May, September, and October, once a week.
9.10.12 Monitoring Requirements for Sample Design
Monitoring requirements and methods are discussed generally in Chapter
11 of this manual. For this sample design, locations, frequency, and
parameters analyzed or recorded are shown in Table 9-15.
In addition to the
and odor monitoring
sponse team will be
residents, to track
written record.
monitoring shown in Table 9-15, micrometerological
will be routinely conducted. An odor complaint re-
formed, to check on all odor complaints from nearby
them to the source, if possible, and to provide a
9.10.13 Cost Estimates
Preliminary estimates (1982 costs) for capital and operational cc
the system presented in the sample design are presented in Tabl
and 9-17. Table 9-16 estimates capital costs
including transport of sludge to the site, as
transport to the site is not included because it is a site unique
tor.
are presented in Tables 9-16
including land, but not
$12,676,000. Sludge
Annual operational costs are estimated in Table 9-17 at $619,000/yr.
Utilizing reasonable equipment life and amortization factors, the unit
costs represented are aproximately $109/ dry metric ton ($99/ton), or
$26/wet m3 ($0.10/wet gal) of sludge disposed.
9.11 References
1. Sacramento Area Consultants. Sewage Sludge Management Program.
Vol. 1: SSMP Final Report, Work Plans and Source Survey. Sacra-
mento Regional County Sanitation District. Sacramento, California,
September 1979. (Available from National Technical Information
Service, Springfield, Virginia, PB80 166739.)
2.
3.
U.S. EPA. Water Quality Criteria, 1972. EPA R3-73-033, National
Academy of Science, Washington, D.C., March 1973. 606 pp. (Avail-
able from National Technical Information Service, Springfield, Vir-
ginia, PB-236 199)
Alexander, M. Introduction to Soil
New York, 1977. pp. 225-271.
Microbiology. 2d Ed. Wiley,
9-40
-------
TABLE 9-15
MONITORING PROGRAM FOR SLUDGE, SOIL, AND WATERS, DESIGN EXAMPLE
Parameter
General and. Mineral
Total flow
Total solids
Volatile Solids
Specific conductance
pll
Total alkalinity
Chloride
Soluble sulfage
Calcium
Magnesium
Potassium
Sodium
Total phosphate
Total nitrogen
Nitrate
Ammonia nitrogen
COO
Dissolved oxygen
Temperature
Turbidity.
Hardness
Heavy Metals
Arsenic
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Silver'
Zinc
Chlorinated Hydrocarbons
Pesticides
ecu's
Total Organic Halogen's
Fecal Collform
Sludge
Dally Storage
Pond, Discharge Twice
Pumps Annually'
* X
* X
X X
X
X
X
X
X
X
X X
X
X
X
X
X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
Soils
Annually
X
*
X
X
X
X
X
X
X
X
X
X
X
X
X
*
*
X
X
X
X
X
X
X
X
X
Ground Mater
Every Other
Month ' Annually*
X X
X X
X X
X X
X X
X X
X X
X X
X *
X X
*
*
X
*
*
X
*
*
*
*
,
*
Creek Hater
Every Other tt
Month Annually
X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X
X
X
X
X
X
X
X
X
X
X
Surface Runoff
Automatic
Sampler"
X
X
X
X
X
X
X
X
X
* Monitoring of this parameter Is required by regulatory agency.
X This parameter is monitored.
9 Front each sludge storage pond.
t Analyze In March.
** Analyze in June.
tfff Analyze daily when sample is collected.
9-41
-------
TABLE 9-16
ESTIMATED CAPITOL COSTS (1982) FOR DEDICATED
LAND DISPOSAL SITE USED AS SAMPLE DESIGN
Item
No.
6
7
8
9
10
11
12
13
14
15
16
17
18
Description
Sludge pump station at sewage treatment plant
and pipeline from sewage treatment plant to the
sludge storage ponds located at the dedicated
land disposal site.
Land purchase, 296 ha (731 ac) at $4,446/ha
($l,800/ac).
Land grading 296 ha (731 ac) at $2,706/ha
($l,100/ac).
Construction of sludge storage ponds, clay lined
with riprap erosion protection, 377,000 m3
(100 M gal) at $10.56 M3 ($0.04/gal).
Construction of surface runoff storage pond
30,776 M3 (8.1 M gal) at S11.88/M3 ($0.045/gal).
On-site drainage control structures
On-site roads, gravel, 15,000 m (49,200 ft) at
$38.40/m ($11.70/ft).
Fencing, chain link, 1.83 m (6 ft), 4,436 m
(14,550 ft) at $49.20/M ($15/ft).
Sludge pump station at sludge storage ponds,
200 hp.
On-site piping, valving, hydrants, etc.
Four subsurface sludge injectors, tractors, and
flexible hoses at $160,000 each.
One tillage tractor.
Miscellaneous onsite improvements, including
office, workman facilities, lighting equipment
warehouse, etc., 558 mz (6,000 ft2) at $7.00/mz
($65/ft2).
Total estimated capitol cost, including land, but
not including transport of sludge to the disposal
site.
Miscellaneous and contingencies
Engineering costs
Interest during construction
Total estimated capitol cost
Capital Cost
1982 S
Not included in
the cost total,
See Chapter 10
1,316,000
801,000
3,981,000
366,000
250,000
576,000
218,000
350,000
890,000
640,000
125,000
391,000
9,904,000
990,000
990,000
792,000
12,676,000
9-42
-------
TABLE 9-17
ESTIMATED OPERATIONAL COSTS (1982) FOR DEDICATED
LAND DISPOSAL SITE USED AS SAMPLE DESIGN
Item
No. Description
1 Labor 6.5 man-years annually at $27,000/man-
year, including fringe benefits
2 Repairs and supplies for mobile equipment
3 Repairs and supplies for stationary equipment
and structures
4 Energy costs, electricity and fuel
5 Sampling, monitoring, and anaysis costs
6 Estimated direct operational costs
7 Management cost at 45%
8 Total annual operational cost, 1982
Operational Cost
1982 $
176,000
175,000
120,000
43,000
24.000
538,000
81,000
619,000
9-43
-------
4. Sacramento Area Consultants. Sewage Sludge Management Program.
Volume 7A: Draft Environmental Impact Report. Sacramento Regional
County Sanitation District, Sacramento, California, September 1979.
(Available from National Technical Information Service, Spring-
field, Virginia, PB80 166820)
5. U.S. EPA. Process Design Manual for Sludge Treatment and Disposal.
EPA-625-1-79-011, Center for Environmental Research Information,
Cincinnati, Ohio, September 1979. 1135 pp. (Available from Na-
tional Technical Information Service, Springfield, Virginia, PB80
200546)
6. Brown and Caldwell. Corvallis Sludge Disposal Study. City of Cor-
vallis, Oregon, April 1977.
7. Brown and Caldwell. Con/all is Sludge Disposal Predesign Report.
City of Con/all is, Oregon, March 1978.
8. Brown and Caldwell. Amendment to Corvallis Wastewater Treatment
Program. Environmental Assessment Dedicated Land Disposal Project.
City of Corvallis, Oregon, April 1978.
9. Brown and Caldwell. Preliminary Draft: Colorado Springs Long-
Range Sludge Management Study. City of Colorado Springs, Colorado,
April 1979.
10. Knight, R. 6., E. H. Rothfuss, and K. D. Yard. FGD Sludge Disposal
Manual. EPRI CS-1515, Michael Baker Jr., Beaver, Pennsylvania,
September 1980. 710 pp.
11. American Society of Civil Engineers. Sanitary Landfill Manual.
ASCE Manuals of Practice 39, New York, September 1976. 61 pp.
12. Criteria for Classification of Solid Waste Disposal Facilities and
Practices (40 CFR, Part 257). Federal Register, 44:53438-53468,
September 13, 1979.
13. U.S. EPA. Process Design Manual: Muncipal Sludge Landfills. EPA-
625/1-78-010. October 1978. 327 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-299 675)
14. Geswein, A. J. Liners for Land Disposal Sites, An Assessment.
EPA-530/SW-137. U.S.' Environmental Protection Agency, Washington,
D.C., March 1975. (Available from National Technical Information
Service, Springfield, Virginia, PB-261 046)
15. Lutton, R. J., G. L. Regan, and L. W. Jones. Design and Construc-
tion of Covers for Solid Waste Landfill. EPA 600/2-79-165, Army
Engineer Waterways Experiment Station, Vicksburg, Mississippi,
August 1979. 276 pp. (Available from National Technical Informa-
tion Service, Springfield, Virginia, PB80 100381)
9-44
-------
16. Sacramento Area Consultants. Dedicated Land Disposal Study -
Sacramento Regional County Sanitation District, Sacramento, Cali-
fornia, September 1979. pp. 403. (Available from National Techni-
cal Information Service, Springfield, Virginia, PB80 166804)
17. U.S. EPA. Process Design Manual for Land Treatment of Municipal
Wastewater, EPA 625/1-89-013. U.S. Environmental Protection
Agency, Center for Environmental Research Information, Cincinnati,
Ohio. October 1981.
18. Drainage of Agricultural Land: A Practical Handbook for the Plan-
ning, Design, Construction, and Maintenance of Agricultural Drain-
age Systems. U.S. Department of Agriculture. Soil Conservation
Service. October 1972.
19. Van Schilfgaarde, J., ed. Drainage for Agriculture.
Society of Agronomy, Madison, Wisconsin. 1974.
American
9-45
-------
-------
CHAPTER 10
FACILITIES DESIGN AND COST GUIDANCE
10.1 General
This chapter is intended to aid in design and preliminary cost estimat-
ing for:
Sludge transport equipment.
Sludge storage facilties.
Sludge application methods.
t Application site preparation.
Supporting facilities.
Reference is frequently made in this chapter to two documents that con-
tain additional specific cost and guidance information, and should be
obtained and used in conjunction with this chapter. These are:
Process Design Manual for Sludge Treatment and Disposal U.S.
EPA, MERL, ORD, September 1979, EPA-625/1-79-011.
Transport of Sewage Sludge, U.S. EPA, MER, ORD, December 1977,
EPA-600/2/77-216.
The selection and design of any individual component of the system
should take into consideration the impact of these decisions upon the
overall system efficiency, reliability, and cost. For example, the most
economical sludge transportation method may not result in the lowest
overall system cost because of resulting higher costs at the treatment
plant and/or land application site. The overall system should always be
kept in mind when designing its individual components.
10.2 Transportation of Sludge
10.2.1 Transport Modes
Potential modes of sludge transportation include truck, pipeline, rail-
road, barge, or various combinations of these four modes (Figure 10-1).
The method of sludge transportation chosen and its costs are dependent
on a number of factors, including:
t Characteristics and quantity of sludge to be transported.
The distance from the POTW plant to the application site(s).
The availability and proximity of the transportation modes to
both origin and destination, e.g., proximity of railroad
spurs, barge waterways, roads, etc.
10-1
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and site characteristics (topography, vegetative cover, soil
type, area available).
Environmental and public acceptance factors.
To minimize the danger of spills, liquid sludges should be transported
in closed tank systems. Stabilized, dewatered sludges can be trans-
ported in open vessels, such as dump trucks and railroad gondolas if
equipped with water tight seals and anti-splash guards (11).
10.2.2 Vehicle Transport
10.2.2.1 Vehicle Types Available
Trucks are widely used for transporting both liquid and dewatered
sludges and are generally the most flexible means of transportation.
Terminal points and haul routes can be readily changed with minimal
cost. Trucks can be used for hauling sludge either to the final appli-
cation site(s) or to an intermediate transfer point such as railroad
yards or a barge loading area. Access to sludge within a site is usu-
ally adequate for truck loading.
Many truck configurations are available ranging from standard tank and
dump bodies to specialized equipment for hauling and spreading sludges.
Depending on the type of sludge to be hauled, the following types of ve-
hicles can be used.
a. Liquid Sludge (Usually Less Than 10 Percent Solids, Dry Weight)
Farm tractor and tank wagon, such as used for livestock man-
ure. Normally used only for short hauls, and by small rural
communities.
Tank truck, available in sizes from 2,000 to 24,000 1 (500 to
6,000 gal)
- Tank truck adapted for field application of sludge in addi-
tion to road hauling.
- Tank truck only used for road hauling to the land applica-
tion site(s) and sludge subsequently transferred to field
sludge application vehicle or irrigation system. Such tank
trucks are often termed "nurse trucks."
10-3
-------
b. Dewatered or Composted Sludge (e.g., Usually 20 to 60 Percent
Solids, Dry Weight)
Dump truck, available in sizes from 6 to 23 m3 (8 to 30 yd3).
t Hopper (bottom .dump) truck, available in sizes from 12 to 19
m3 (15 to 25 yd3).
Either of the above types of truck can be used only for haul-
ing the sludge to the land application site(s), or can be
adapted to both haul the sludge and spread the sludge.
Figure 10-2 shows photographs of typical types of the trucks listed
above.
10.2.2.2 Vehicle Size and Number Required
To properly assess the size and number of vehicles needed for transport-
ing sludge from the treatment plant to the application site(s), the fol-
lowing factors should be considered:
Quantity of sludge, present and future.
Type of sludge, liquid, dewatered, or composted.
Distance from treatment plant to application site(s) and tra-
vel time.
t Type and condition of roads to be traversed, including maximum
axle load limits and bridge loading limits.
t Provisions for vehicle maintenance.
Scheduling of sludge application. In many areas, there is a
large seasonal variation (due to weather, cropping patterns,
etc.) in the quantity of sludge which can be applied. The
transport system capacity should be designed to handle the
maximum anticipated sludge application period, taking into
consideration any interim sludge storage capacity available.
Percent of time when the sludge transport vehicles will be in
productive use. A 1977 study (1) of truck sludge hauling at
24 small to medium size communities showed that liquid sludge
haul trucks were in productive use an average of 48 percent of
the time (range 7 to 90 percent) based upon an 8-hr day and 5-
day week. Average use for dewatered sludge haul truck was re-
ported even less at 29 percent.
Tables 10-1 and 10-2 provide a guideline for estimating the number of
trucks needed for transporting liquid and dewatered sludge, respec-
tively. While the tables provide a means for making preliminary compar-
isons, they are only a starting point in the decision making process for
10-4
-------
Figure 10-2A. 6,500-galTon liquid sludge tank truck (courtesy of
Brenner Tank Co.).
Fi gure 10-2B,
3,300 gallon liquid sludge tank truck with 2,000-
gallon pup trailer (.courtesy of Brenner Tank Co..)
10-5
-------
Figure 10-2C8-
25-cubi c-yard dewatered
of Converto Mfg. Co.).
sludge haul truck (courtesy
Figure 10-2D.
12-cubic-yard dewatered sludge spreader vehicle
(courtesy of Ag-Chem Equipment Co.).
10-6
-------
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10-8
-------
a specific project. For example, they can be used to quickly compare
vehicle needs as a function of whether to truck transport liquid sludge
at 5 percent solids or an equivalent quantity of dewatered sludge solids
at 25 percent solids. Assuming a liquid sludge quantity of 57 mil 1/yr
(15 MG/yr), 58,000 mt/yr (64^000 T/yr), and an equivalent quantity of
dewatered sludge of 11,470 m3/yr (15,000 yd^/yr), 12,000 mt/yr (13,000
T/yr), and a one-way distance of 32 km (20 mi) from treatment plant to
application site, Tables 10-1 and 10-2 indicate that for an 8 hr/day
operation, approximately six 9,450 1 (2,500 gal) tank trucks are neces-
sary to transport the liquid sludge, and only one 11.5 rrr (15 yd"3) truck
is necessary to transport the dewatered sludge. The difference in fuel
purchase is 202,000 1/yr (53,500 gal/yr) versus 50,300 1/yr (13,300
gal/yr), and in driver time is 15,500 hr/yr versus 2,600 hr/yr. The
above savings in transportation cost of dewatered sludge versus liquid
sludge can then be compared to the cost of dewatering the sludge.
The reader should be aware that the above example is obviously highly
simplified in that it assumes that the sludge transport operation takes
place 360 day/yr, provides an average of only 10 percent plus 2 hr/day
for truck idle and maintenance time, and gives no consideration to ef-
fects of sludge type upon operating costs at the sludge application
site(s).
10.2.2.3 Other Considerations
The haul distance should be minimized to reduce costs, travel time and
the potential for accidents en route to the application site(s). Unfa-
vorable topographic features, road load limits, population patterns,
etc., may influence routing such that the shortest haul distance is not
the most favorable.
Effective speed and travel time can be estimated from the haul distance,
allowing for differences in speed for various segments of the route and
the anticipated traffic conditions. Periods of heavy traffic should be
avoided from a safety standpoint, for efficiency of operation, and for
improved public acceptability.
The existing highway conditions must be considered in the evaluation of
truck transport. Physical constraints, such as weight, height, and
speed limits, may limit truck transport and will .definitely influence
vehicle and route selection. Local traffic congestion and traffic con-
trols will not only influence routing, but should also be considered in
determining the transport operation schedule. Public opinion on the use
of local roadways, particularly residential streets may have a signifi-
cant effect on truck transport operations and routing.
Fuel availability and costs can have a profound impact on the operation
and economy of sludge hauling activities. Larger trucks tend to be more
fuel efficient than smaller ones. Also, short haul distances over flat
terrain will have lower fuel requirements than long distances and hills.
Manpower requirements can be determined from the operating schedule.
10-9
-------
Truck drivers and mechanics as well as loading and unloading personnel
will be required for large sludge hauling operations. Small operations
may combine these roles into one or two persons.
The operating program for sludge hauling can be simple or very complex.
An example of a simple hauling operation would be a case where all the
sludge generated each day is hauled to a dedicated land disposal site
and discharged into a large capacity sludge storage facility. In such a
simple case, the designer can easily develop an operating schedule for
sludge hauling based upon the following:
Quantity of sludge which will, be hauled.
t Average round trip driving time requirement.
Sludge loading and unloading time requirement.
Truck maintenance downtime.
Estimated truck idle time, in addition to maintenance down-
time.
Haul truck capacity.
Length of working shifts and number of laborers (drivers,
etc.) working.
» Safety factor for contingencies, e.g., variations in sludge
quantity generated, impassible roads due to weather, etc.
At the opposite extreme from the simple case described above is the de-
velopment of a complex sludge hauling schedule for an agricultural uti-
lization program involving many privately owned farms. Such a program
is complicated by the need to take into account the following additional
factors:
t The variation in distance (driving time) from the POTW to the
privately owned farms or forests accepting the sludge.
No sludge
sites.
storage capacity provided at the sludge application
Weather, soil conditions, and
limit the number of days when
be applied to farmland.
cropping patterns that severely
and locations where sludge can
As an example of the large variations in sludge hauling schedules for a
complex agricultural utilization program, Table 10-3 shows the projected
monthly sludge distribution for the Madison, Wisconsin, "METROGRO" proj-
ect. As can be seen, projected sludge volume distribution in the maxi-
mum sludge utilization months (e.g., September) is six times that of the
10-10
-------
miminum sludge utilization months (e.g., February). The designer should
provide for the necessary sludge transport, application, etc., equipment
and labor to handle the maximum sludge distribution months. This re-
sults in under utilization of equipment during the low demand sludge
distribution months, as well as the potential problem of shifting em-
ployees (e.g., drivers) to other productive work. Some cities have sup-
plemented their forces with private haulers during peak periods to help
overcome this problem.
TABLE 10-3
PROJECTED MONTHLY SLUDGE DISTRIBUTION FOR
AGRICULTURAL SLUDGE UTILIZATION PROGRAM, MADISON, WISCONSIN (4)
Month
January
February
March
April
May
June
July
August
September
October
November
December
% of Annual
2.5
2.5
2.5 .
7.5
7.5
5
10
12.5
15
15
15
5
Gal /Month
(x 1,000)
1,250
1,250
1,250
3,750
3,750
2,500
5,000
6,250
7,500
7,500
7,500
2,500
Gal /Day*
J2.500
62,500
62,500
187,500
187,500
125,000
' 250,000
312,500
375,000
* 375,000
375,000,
125,000
* Based on 20-day/month operation.
Metric conversion:
1 gal =3.78 1
a. Contract Hauling Considerations
Many cities, both large and small, use private contractors for sludge
hauling, and sometimes sludge application as well. The economic feasi-
bility of private contract hauling versus use of publically owned vehi-
cles and public employees, should be analyzed for most new projects. If
a private contractor is used, it is essential that a comprehensive con-
tract be prepared which considers the total management plan and avoids
city liabilty for mistakes by the contractor. As a minimum, the con-
tract should cover the following responsibilities:
Liability and .insurance for equipment and employees.
Safety and public health
ments.
protection procedures and require-
10-11
-------
Estimated sludge quantities and handling procedures.
t Methods for and responsibility for handling citizen com-
plaints, and other public relations.
Accident, spill, violation, etc., notification and mitigation
procedures.
Monitoring procedures, record keeping and reporting require-
ments.
Responsibility for obtaining and maintaining permits, licen-
ses, and regulatory agency approvals.
The usual legal document provisions for non-performance re-
lief, termination, etc.
In some instances, sludge is hauled away from the POTW by the user,
e.g., farmer, commercial forest grower, etc. Again, the city should ob-
tain competent legal council to avoid potential liability due to negli-
gence by the private user/hauler.
b. Additional Facilities Required for Hauling Operation
Sludge loading facilities at the POTW should be accessible and in a con-
venient location. Depending on the type of sludge being hauled, hop-
pers, conveyor belts, or pipelines are needed to load the trucks. Vehi-
cle storage and a maintenance/repair shop may be located at the plant
site. Equipment washdown,facilities and parking should be nearby.
Similar facilities for truck unloading, etc., may be necessary to the
sludge application site(s) and/or sludge storage facility.
10.2.2.4 Cost Estimation Factors
Capital as well as operation and maintenance (O&M) costs for truck
transportation are highly variable and dependent on the physical form
and quantity of the sludge, hauling distances, labor costs, fuel costs,
and other transport rate structure factors (10). Generalized capital
and O&M costs include the cost of the vehicles plus the loading and un-
loading facilities (see Tables 10-4 through 10-6), and can be used to
roughly compare costs. Based on the example provided in Section
10.2.2.2, the one-way transportation for 32 km (20 miles) of 57 mil 1/yr
(15 MG/yr) of liquid sludge can be compared to an equivalent 11,470 m3/
yr (15,000 yd^/yr) of dewatered sludge. Using Tables 10-4 through 10-6,
these estimated costs (1980) are compared below:
Liquid sludge
- Capital cost of six 9,450 1 (2,500 gal) tank trucks
$65,000 each (Table 10-4), $390,000
at
10-12
-------
TABLE 10-4
CAPITAL AND OPERATING COST OF SLUDGE HAULING TRUCKS
Capital
Cost
Type of Sludge
Liquid
Dewatered
Type of Truck
Tank truck
Dump truck, 2 axle
Dump truck, 3 axle
Dump truck, 3 axle
(plus transfer trailer)
Dump truck, 3 axle
(plus pup trailer)
Bottom dump truck
(hopper)
Capacity
1,200 gal
2,500 gal
5,500 gal
8-10 yd3,
10-15 yd:?
15-25 ydj
n
15-25 ydj
Q
25 ydj
x 1
35
60
90
35
65
80
80
95
,000
- 40
- 65
- 100
- 40
- 70
- 85
- 85
- 110
Opera£ign
Costs
$/mi 1 e
0.30
0.38
0.45
0.30
0.38
0.45
0.45
0.54
* Includes operator, fue.U, maintenance (labor and supplies) and insurance;
does not include loading^, Engr. Cons. Cost Index 3237. Cost estimates for
mid 1980.
Metric conversions factors:
1 gal = 3.78 1 ,
1 yd-3 = 0.764 mj
1 mile = 1.609 km.
TABLE 10-5
TRUCK FACILITIES: CAPITAL, OPERATION AND
MAINTENANCE DATA,.LIQUID SLUDGE*
Annual Sludge Volume, Million Gallons
Item
Capital Cost1"
Loading pump, pipe, hose
Enclosed .truck loading
1.5
,5
15
11,250, 11,250 12,750
50
21,000
150
30,000
facility^ :-
Truck ramp for unloading
Unloading truck facility
and office
Subtotal Capital Costs
Operation & Maintenance,
$/yr
7,500
-22,500
15,000
56,250
11,000
10,500
22,500
15,000
59,250
14,000
15,000
45,000
22,500
95,250
18,000
30,000
75,000
30,000
156,000
28,000
37,500
112,500
45.000
215,000
41,000
* Assumptions: Pumps and piping sized to fill truck in 20 minutes; use plant
sludge storage;'gravity unloading at disposal site.
t All costs updated to mid-1980 using Engineering-Construction Cost Index.
# Based on $41/ft2 for office and $25/ft2 for truck enclosure.
Metric conversion factors:
1 mil gal = 3.78.mil 1
1 ft2 = 0.0929 mz.
10-13
-------
TABLE 10-6
TRUCK FACILITIES: CAPITAL, OPERATION AND
MAINTENANCE DATA, DEWATERED SLUDGE*
Annual Sludge Volume,
Item
Capital Cost1"
Conveyor
Loading; hopper
Enclosed truck loading
facility
Truck Ramp
Unloading truck facility
and office
Subtotal Capital Costs
Operation & Maintenance,
$/yr
1.5
15,000
15,000
7,500
22,500
15.000
75,000
7,000
_5
15,000
15,000
7,500
22,500
15,000
75,000
8,000
_15
15,000
. 15,000
7,500 ,
22,500
15,000
75,000
9,000
1,000 cu
50
30,000
22,500
15,000
30,000
1 22.500
120,000
17,000
yd
150
30,000
30,000
15,000
45,000
37,500
157,500
25,000
* Assumptions: Equipment sized to fill truck in 20 minutes; loading hopper
sized for one truck load and gravity discharge into truck;
gravity unloading at disposal site.
t All costs updated to mid 1980 using Engineer Construction Cost Index.
$ Based on $41/ft2 for office and'$25/ft2 fr truck enclosure.
Metric conversion factors:
1,000 yd3 * 764 m3
1 ft* = 0.0929 mz
10-14
-------
- Capital cost of loading and unloading facilities (Table 10-
5), $95,250
- Estimated total capital costs of liquid sludge transport,
$485,250
-Truck operating costs, $0.24/km ($0.38/mi) (Table 10-4) x
386,000 km (240,000 mi) (Table 10-1), $91,200
- Loading and unloading facility operating cost (Table 10-5),
$18,000
- Estimated annual O&M costs for liquid sludge $109,200.
Dewatered sludge
- Capital cost of one 11.5 m3 (15 yd3) dump truck (Table 10-
4), $85,000 "" .
- Capital cost of loading and unloading facilities (Table 10-
6) $75,000
- Estimated total capital cost for dewatered sludge, $160,000
- Truck operating costs, $0.28/km ($0.45/mi) (Table 10-4) x
64,400 km (40,000'mi) (Table 10-2), $18,000
- Loading and unloading facility operating costs (Table 10-6),
$9,000
- Estimated annual O&M costs for dewatered sludge, $27,000.
This example indicates that dewatered sludge could be transported for
approximately 30 percent of the cost of transporting an equivalent quan-
tity of liquid sludge. Similar analyses could be conducted to approxi-
mate relative costs of contract hauling versus public agency purchasing
and operating its own vehicles.
10.2.3 Pipeline Transport
Generally, only liquid sludge of 8 percent solids, or less, can be
transported by pipeline (17). However, sludges with higher solids con-
centrations have been pumped, e.g., the city of Seattle, Washington, is
reported to be pumping sludge containing up to 18 percent solids. Other
important factors include:
e Availability of land for sludge application for projected
long-term periods. Pipeline transport is not usually feasible
if there are multiple, widely separated land application
sites, or if the application site(s) has a short useful life.
10-15
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Sufficient sludge volume to justify the high capital costs of
a pipeline, pump station(s) and appurtenances. Generally,
municipal sewage treatment plants sized below 19 mil I/day (5
mgd) do not generate sufficient sludge volume to justify pipe-
line transport, unless the distance to the land application
site is short, e.g., less than 3 km (2 mi).
Existence of a relatively undeveloped and flat pipeline right-
of-way alignment between the sewage treatment plant and the
land application site. It is very expensive to construct a
new pipeline through developed residential/commercial areas or
through hilly terrain.
If factors such as those listed above are favorable, sludge transport by
pipeline often can be less expensive than truck transport per unit vol-
ume of sludge.
10.2.3.1 Pipeline Design
The effect of solids concentration on the sludge flow characteristics is
of fundamental importance to economic pipeline design. Digested sludges
have been observed to exhibit both newtonian and plastic flow character-
istics. Figure 10-3 shows the influence of sludge solids concentrations
on minimum velocities required for full turbulent flow. The figure also
indicates the frictional head loss and the range of velocities for eco-
nomical transportation. Below about 5 percent solids, the sludge flow
shows newtonian nature, whereas at concentrations above 5 percent, plas-
tic flow characteristics are observed. At solids concentration below 5
percent, the economics of sludge transport will resemble water transport
costs with respect to frictional head loss and power requirements. The
most cost-effective pipeline design usually assumes operation just
within the upper limits for newtonian flow (8) (approximately 5.5 per-
cent solids). An extensive discussion on head loss calculations and
equations for sludge pipelines and sludge pumping can be found in Chap-
ter 14 of the Process Design Manual for Sludge Treatment and Disposal
(16).
Various pipeline materials are used for transporting sludge. These in-
clude steel, cast iron, asbestos-cement, concrete, fiberglass, and PVC.
For long-distance, high-pressure sludge pipelines, steel pipe is most
commonly used. Corrosion can be a severe problem unless properly con-
sidered during design. External corrosion is a function of the pipe ma-
terial and corrosion potential of the soil, and can be controlled by a
suitable coating and/or cathodic protection system. Laboratory tests
simulating several digested sludge lines indicated that with proper de-
sign only moderate internal corrosion rates should be expected in long-
distance pipelines conveying sludge. If most of the grit and other
abrasive materials are removed from the digested sludge, wear due to
friction is not a significant factor in pipeline design (16).
10-16
-------
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Figure 10-3. Hydraulic characteristics of sludge solids (5)
10-17
-------
10.2.3.2 Pipeline Appurtenance Design
Commonly used sludge pipeline appurtenances are briefly discussed below
(19)(20). More extensive discussion is found in Chapter 14 of the Pro-
cess Design Manual for Sludge Treatment and Disposal (16).
a. Gauges
Pressure gauges are installed on the discharge side of all pumps. They
may also be installed on the suction side of pumps for purposes of head
determination. Protected, chemical-type gauges are generally used for
sludge pumping.
b. Sampling Provisions
All sludge pumps, either on the pump itself or in the pipe adjacent to
the pump, are usually provided with 2.5 to 3.8 cm (1 to 1-1/2 in) sam-
pling cocks with plug valves.
c. Cleanouts and Drains
Sludge pipelines should be provided with separate cleanouts and drains
for easy clearance of obstructions. Blind flanges and cleanouts should
be provided at all changes of direction of 45 degrees or more. Valved
drains should be provided at all low points in the pipeline. Pressure
vacuum relief valves should be provided at all high points in the pipe-
line. Minimum size at cleanouts is 10 cm (4 in), with 15 cm (6 in) size
preferred for access of tools.
d. Hose Gates
A liberal number of hose gates should be installed in the piping, and an
ample supply of flushing water under high pressure should be available
for clearing stoppages.
e. Measuring Sludge Quantities
Pump running time totalizers provide a simple method of approximating
the quantities of sludge pumped. For more sophisticated measurement
Venturi meters, flow tubes or magnetic meters with flushing provisions
are used. Sludge meters should have provision for bypassing.
10.2.3.3 Pump Station Design
Pump stations used to pump sludge through long-distance pipelines should
be carefully designed by experienced engineers. This section is not in-
tended to be a comprehensive guide to design of such stations, but
10-18
-------
rather to highlight important design considerations, and to make refer-
ence to more extensive information. Factors of importance when design-
ing long distance sludge pump station design include:
Characteristics of the sludge, e.g., type of sludge, solids
content, how well stabilized, abrasive particle content, vis-
cosity, etc.
Quantity of sludge, and type and capacity of sludge storage
ahead of the sludge pumps and receiving the sludge at the
pipeline terminus. ,
Pressure which the pumps must overcome, both pipeline friction
loss and static (elevation difference) head.
Need for standby reliability, i.e., how long can the pump sta-
tion be out of service for maintenance, power failure, etc.,
as determined by available sludge storage alternate means of
sludge transport, etc.
Anticipated pump station life.
Need for future expansion of capacity, e.g., provision of
space for future pumps, power sypply, piping, etc.
Ease of operator operation and maintenance.
Each of the above factors is briefly discussed in the following para-
graphs.
The sludge most easily pumped long distances has a solids content below
6 percent, is well stabilized (relatively low in volatile solids), is
low in abrasive grit, and is free of large particles and stringy mate-
rial. Sludges possessing other characteristics can be dealt with during
design, but will normally cause increased construction, operation, and/
or maintenance costs.
The quantity of sludge to be pumped obviously determines the capacity of
the pumps arid the pump station. Capacity is measured by maximum sludge
pumping rate required; therefore, it is desirable to provide for as con-
stant an output pumping rate as possible over long periods of the day.
Ideally, the sludge pumps will withdraw the sludge from a large volume
storage facility (e.g., a digester) at a steady rate. If possible,
avoid small pump supply storage tanks which require the sludge pumps to
frequently start and stop. An additional important point is that the
pump supply storage should have a liquid level higher than the elevation
of the pump suction intake. Sludge pumps work much more efficiently and
reliably if they have a positive suction head.
10-19
-------
The pressure which the sludge pumps must overcome is the elevation dif-
ference between the pump station and the highest point of the sludge
pipeline to the application site, plus the friction loss in the pipe and
fittings at the maximum sludge pumping rate. The elevation difference
(static head) is fixed by the topography of the pipeline alignment. The
head loss due to friction, however, will vary and can be expected to in-
crease with time due to gradual deterioration of the pipeline, buildup
of internal sludge deposits, and other factors. The designer, there-
fore, should provide a safety factor in calculating total pressure loss
due to friction in the pipe and fittings. An excellent discussion of
sludge pipeline head loss due to friction is found in Chapter 14 of the
Process Design Manual for Sludge Treatment ,and Disposal (16)."
Various types of pumps are used to pump sludge. "Pumps currently uti-
lized for sludges include centrifugal, torque, plunger, piston, piston/
hydraulic diaphragm, ejector and air lift, pumps. Table 10-7 presents a
matrix which identifies various types of" sludges, and provides guidance
to the suitability of each type of pump for handling these" sludges. See
Chapter 14 in the Process Design Manual for Sludge Treatment and Dis-
posal (16) for a more detailed description of each pump type listed
above. Centrifugal pumps are commonly selected for long distance sludge
pumping because they are more efficient (i.e., use less energy), and can
develop high discharge pressures. Centrifugal pumps are not generally
used for heavy primary sludges, however, because they cannot handle
large or fibrous solids.
The number of pumps installed in a pump station will depend largely on
the station capacity and the range in sludge volumes which will be
pumped. It is customary to provide a total pumping capacity equal to
the maximum expected inflow with at least one of the pumping units out
of service. In stations handling small flows two pumps are usually in-
stalled, with each pump capable of meeting the maximum inflow rate. For
larger stations, the size and number of pumps should be selected so that
the range of inflow can be met without starting and stopping pumps too
frequently (19).
Proper design must provide a means to add wastewater effluent (or water)
to the sludge pumping system for purposes of diluting the sludge and for
flushing the pipeline.
It should be assumed that the pump station will occasionally be inopera-
tive due to maintenance, power failure, etc. The designer should pro-
vide sufficient storage capacity for sludge and/or standby power to han-
dle at least two days of sludge pumping station shutdown. Emergency
tank truck hauling by a private firm is one alternative which could be
contracted for beforehand.
Unless the designer is certain that future pump station expansion will
not be necessary, space, fittings, etc. should be provided in the pump
station for future additions of additional pumping capacity.
10-20
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10-21
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10.2.3.4 Cost Estimation Factors
Pipeline transportation is a capital intensive system. The cost of the
major facilities is directly related to the capacity and length of the
pipeline system. Variables affecting the cost of pipeline transporta-
tion of sludge include:
t Type of sludge.
Sludge volume.
t Solids content and viscosity.
Transportation distance.
Pipeline alignment.
§ Topography of the area through which the pipeline is to be
constructed.
Table 10-8 provides estimated pipeline costs relative to pipeline diame-
ter, and Table 10-9 shows the estimated unit cost of different types of
crossings that may be encountered when installing pipelines.
Pump station costs were developed from information developed for the EPA
(5). Since costs were required for numerous pumping stations with a
wide range of capacities, capital cost for each pump station was based
on a cost of $110,000 for capacities of up to 25 horsepower and $1,800
for each additional horsepower above 25.
The cost approximations provided for sludge pump stations in the para-
graph above, and for pipelines in Tables 10-8 and 10-9, are very sim-
plistic. They can, however, be used to provide initial gross cost com-
parisons for pipeline transport versus other alternatives for sludge
transport. Assume, for example, that the sludge volume generated is
56.7 mil 1/yr (15 MG/yr) and the land application site is only 3 km (2
mi) distant. Preliminary engineering calculations indicate a pipeline
diameter of 20.3 cm (8 in) and a pump station of 50 horsepower are
needed. Using cost noted earlier, it is estimated that the pipeline
cost would be 3,219 m x $85/m ($26 x 10,560 ft) = $275,000, and the pump
station cost is $110,000 + 24 add. horsepower x $1,800 = $155,000, for a
total of $430,000 in capital costs. This cost compares favorably with
the cost of truck transport (Tables 10-1 through 10-6), and the engineer
should proceed to conduct a more thorough evaluation of the pipeline
transport alternative.
10-22
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TABLE 10-8
ESTIMATED PIPELINE COST (1980) (6)
Pipeline Diameter (in)
4
6
8
10
12
14
16
18
20
Pipeline Costs ($/LF)
22.4
23.7
26.0
28.1
30.3
34.7
41.2
47.8
64.6
Assumes: No rock and no major problem; one major highway
crossing per mile; one single rail crossing per
five miles; nominal number of driveways and minor
roads ENR-Cons. Cost Index 3237.
* Costs for installed pipelines buried 3 to 6 ft, for 6 to
10 ft depth add 15%, for hard rock excavation add 70%.
Metric conversion factors:
1 in = 2.54 cm
1 ft = 0.3048 m
TABLE 10-9
ESTIMATED PIPELINE CROSSING COSTS (1980) (6)
Crossing Unit Cost ($)
Highway, two-lane 16,000
Highway, four-lane 19,000
Highway, divided multiple-lane 32,000
Railroad crossing (per track) 12,000
Small river 73,000
Major river ' 290,000
10-23
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10.2.3.5 Decision Making Factors
The major factors to consider in the initial evaluation of sludge pipe-
line transport include:
Lack of flexibility compared to truck transport. The pipeline
has a fixed alignment and terminus. It is necessary that the
land application site(s) have a sufficient useful life to jus-
tify the capital expense of the pipeline and pump station(s).
Sufficient sludge volume generation to justify the initial
capital cost. Even a small pump station and pipeline will
cost at least $400,000 to build. If one or two tank trucks
can do the job instead, truck transport will often be more
cost effective.
Need to acquire pipeline right-of-way. Possible pipeline
alignments that avoid probable right-of-way easement problems
should be evaluated. Condemnation, when necessary, is expen-
sive and time consuming, and may cause problems in community
acceptance.
If pipeline transport is selected, the following paragraphs briefly dis-
cuss some major design considerations.
a. Alternate Routes Considered
Preliminary planning should be used to reduce the number of potential
pipeline routes. Generally, one route will be clearly favorable over
the others, however, due to unknown or hidden conditions, a certain
amount of flexibility should be maintained until the final design is
begun. Crossings can add significantly to the cost of the pipeline and
to the complexity of construction. The shortest distance with the least
elevation difference and fewest crossings should be the primary goal.
b. Operating Program
A comparison of constant versus variable speed pumps is important in de-
termining the design flow through the pipeline. Variable speed pumps
allow for continuous operation and lower storage requirements. Although
constant speed pumping will require more storage, for peak flow dampen-
ing by equalization, it is usually more energy efficient. The maximum
and minimum flow velocities are an important consideration in pipeline
design. For sludge transport, 1 mps (3 fps) is a satisfactory value;
slower rates can promote solids settling and decomposition, while higher
rates can cause scouring and increase head loss. Since pipelines repre-
sent a significant investment and have long service lives, they should
be sized to permit efficient operation under existing conditions, yet
also provide adequate capacity for future growth.
10-24
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c. Pipeline Design
Pipeline friction losses should be minimized since they contribute sig-
nificantly to the pumping requirements. Abrupt changes in slope and
direction should be minimized. Depending on the nature of the sludge
and the characteristics of the soil, corrosion control features should
be incorporated in the pipeline design. Air and vacuum relief valves
should be provided at high points in the line, drains at low points,
clean-outs at abrupt changes in direction, and frequently spaced isola-
tion valves to allow shutdown in case of pipe failure and repair.
d. Pumping Facilities
More than one pump station may be needed if the pipeline distance is
long. The number of pump stations should be balanced with the size and
number of pumps required to determine the most cost effective combina-
tion. Pumps should be appropriate for the type of sludge to be pumped
and standby pumping units must be provided.
e. Emergency Operation
Several days storage should be provided in
Digesters can be used for this purpose, if
should normally be provided if there are not
electricity to the pump stations. Additional
for standby power under certain conditions,
tion is preferable.
f. Excavation Condition Verification
case of equipment failure.
available. Standby power
two independent sources of
storage may be substituted
although continuous opera-
Field tests
conditions.
established
to isolate
should be used to
Borings should be
but prior to final
areas where special
establish or verify the subsurface soil
taken after the pipeline route has been
design. The field tests should be used
design considerations are needed. If
highly unusual localized conditions exist, they should be avoided, if
possible, or additional field tests made.
Existing or other planned underground utilities should be located and
field verified, if possible. If exact locations cannot be established,
the contractor should be held responsible for locating them during con-
struction.
g. Acquisition of Right-of-Way
Right-of-way easements must be acquired for pipelines on private prop-
erty. This process should be initiated in the early stages of the proj-
ect. The preferable method is to obtain access rights on easements
owned or controlled by other utilities when possible, or to negotiate
with landowners. Condemnation is a lengthy, complex procedure which
should be avoided if possible.
10-25
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10.2.4 Other Transport Methods
Rail car and barge transport are other transport methods for sludge.
These methods are normally only considered by large cities for long dis-
tance transport to land application sites. In 1982, the city of Chicago
operated the only major sludge barging operation in the United States to
a land application site, though several large cities still barge sludge
for ocean disposal. No cities use rail transport. Because potential
systems for using barge or rail transport of sludge are so large, expen-
sive, and unique, this manual provides only a brief discussion of these
transport methods in the following sections.
10.2.4.1 Rail Car
Rail transport of sludge is rare and considered only if the quantity of
sludge is large, the transport distance is long, and rail lines are in
the vicinity of the treatment plant and land application area. Liquid
sludge can be hauled by tank cars, while dewatered sludge can be hauled
in either open or closed hopper cars. Specially designed tank cars of
75,000 1 (20,000 gal) capacity are available for transporting liquid
sludge. The hauling of liquid sludge is similar to moving any other
liquid commodity by rail. However, due to the properties of the liquid
sludge, problems could arise from the separation of liquid and solid
phases during transit. Hauling dewatered sludge by rail closely resem-
bles hauling coal or ore (8). Bridging of dewatered sludge may be a
problem. Hopper cars that could be used for dewatered sludge transport
typically have a capacity of about 76 m3 (100 yd3). For a more detailed
discussion on rail transport, refer to Chapter 14, Section 14.3.2, in
the Process Design Manual for Sludge Treatment and Disposal (16).
10.2.4.2 Barge Transport
Barges can also be used for hauling liquid or
suitable waterways exist. Although barging is a
tation, it offers high capacity with low cost primarily
dewatered sludge where
slow means of transpor-
to
due
the large
volumes hauled and low investment. For more information on different
types and sizes of barges and the number of barges required to haul dif-
ferent sludge quantities, refer to Chapter 14, Section 14.3.3 in the
Process Design Manual for Sludge Treatment and Disposal (16).
10.2.4.3 Cost Estimation Factors
10.2.4.3.1 Rail Car
Cost information for different types of rail cars, including operating
costs are presented in Chapter 14, Section 14.3.2, in the Process Design
Manual for Sludge Treatment and Disposal (16).
10-26
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10.2.4.3.2 Barging
Costs for barge hauling can be significantly influenced by:
Volume hauled.
« Tug speed.
Travel distance.
Existing water conditions.
See Process Design Manual for Sludge Treatment and Disposal (Chapter 14,
Section 14.3.3]) (16) information for detailed barging costs.
10.3 Sludge Storage
10.3.1 Storage Requirements
Sludge storage is necessary to accommodate fluctuations in sludge pro-
duction rate, breakdowns in equipment, agriculture cropping patterns,
and adverse weather conditions which prevent immediate sludge applica-
tion to the land. Storage can potentially be provided at either the
treatment plant, the land application site(s), or both. Chapter 15 in
the Process Design Manual for Sludge Treatment and Disposal (16) pre-
sents methods for estimating sludge storage capacity and describes vari-
ous storage facilities. In addition, Chapter 9 of this manual includes
sections covering sludge storage volume calculations and preliminary
storage facility design considerations for the dedicated land disposal
option, which may be helpful in the design of any large volume, open
lagoon type sludge storage facility.
Long-term storage of sludge in lagoons for 5 years or more is not uncom-
mon. When the lagoons are near capacity, the city contracts with a pri-
vate contractor to remove the sludge and utilize it in a land applica-
tion program. Several private firms specialize in this service, and
supply all of the labor, equipment, and put-lie relations required.
10.3.2 Storage Capacity
10.3.2.1 Sludge Volume and Characteristics
Sludge characteristics vary with sludge origin, retention time (sludge
age), and the type of sludge treatment. Data on the typical quantities
of sludge produced from various treatment processes are presented in
Chapter 3, Table 3-4, in the EPA Process Design Manual for Municipal
Sludge Landfills (18). The different types of storage, the methods by
which the sludge can be stored, and applicable detention times for each
type of storage are summarized in Chapter 15, Table 15-1, in the Process
Design Manual for Sludge Treatment and Disposal (16).
10-27
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10.3.2.2 Climate Considerations in Evaluating Sludge Storage
The designer should consider all the following factors:
Historical precipitation
plication site area.
and temperature records for the ap-
Regulatory agency requirements pertinent to the land applica-
tion of sludge on frozen, snow covered, and/or wet soil.
The ability of the sludge application equipment being used to
operate on wet or frozen soil.
The drainage characteristics of the application site(s) as
they affect the time required after precipitation to dry suf-
ficiently to accommodate equipment.
Clearly, the sludge storage capacity required due to climate considera-
tions is greatly influenced by site specific factors. A review of land
application system designs -in the United States indicates that sludge
storage volume provided ranges from a minimum of 30 days in hot, dry
climate up to 200 days in cold, wet climates.
The U.S. EPA conducted a computer analysis of approximate storage re-
quirements for wastewater to land application systems in the United
States (10), as shown in Figure 10-4. No similar analysis exists (1982)
for sludge application systems. Figure 10-4 is included in this manual
to show general regional variations in storage requirements due to cli-
mate. For most sludge application systems, the actual storage require-
ment will usually exceed the days shown in Figure 10-4.
10.3.2.3 Sludge Application Scheduling Considerations
Evaluating Sludge Storage
in
The majority of existing sludge land application systems in the United
States are applying sludge to privately owned land. This requires a
flexible schedule to conform with local farming practices. Scheduling
limitations will result from cropping patterns, and typically the de-
signer will find that much of the agricultural land can only receive
sludge during a few months of the year. (The Madison, Wisconsin, pro-
gram [Table 10-3] applies over 68 percent of its sludge to farmland dur-
ing the 5-month period from July through November.)
The sludge application to forest sites should be scheduled to conform
with tree grower operations and the annual growth-dormant cycle of the
tree species.
Sludge application for reclamation of disturbed land must be scheduled
to conform to vegetative seeding and growth patterns and also to private
landowners operational schedules.
10-28
-------
188
SHADING DENOTES REGIONS WHERE
THE PRINCIPAL CLIMATIC CONSTRAINT
TO APPLICATION OF WASTEWATER
IS PROLONGED WET SPELLS
BASED ON O °C (32 °F)
MEAN TEMPERATURE
1.25 Cm/d PRECIPITATION
2.5 cm OF SNOWCOVER
500
1000
SCALE
KILOMETERS
Figure 10-4.
Storage days required as estimated from the use of
the EPA-1 computer program for wastewater-to-land
systems. Estimated storage based only on climatic
factors.
10-29
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The dedicated land disposal option is usually only limited by climate
considerations and soil conditions, and not by other scheduling limita-
tions.
10.3.2.4 Calculation of Sludge Storage Capacity Required
A simple method of estimating sewage storage capacity required is to es-
timate the maximum number of days of sludge volume generation which
should be stored. The estimate of the maximum number of days is based
on climate and scheduling considerations discussed in the previous sub-
sections, plus a safety factor. Often, the responsible regulatory
agency will stipulate the minimum number of days of sludge storage which
must be provided. Calculations for this simple approach are shown below:
Assume
1. Average rate of dry sludge solids generated by POTW is 589 kg/
day (1,300 Ib/day).
2. Average sludge contains 5 percent solids.
3. One hundred days storage to be provided.
Solution
1. S^kg/day = 11,778 kg/day (26,000 Ib/day) of liquid
2.
3.
11,778 kg/day =
produced.
11,778 I/day (3,118 gal/day) of liquid sludge
11,788 I/day
required.
x 100 days = 1.2 mil 1 (312,000 gal) of storage
A more sophisticated method of calculating sludge storage required is to
prepare a mass flow diagram of cumulative sludge generation and pro-
jected cumulative sludge application to the land application site(s), as
shown in Figure 10-5. The figure uses data from Madison, Wisconsin (see
Table 10-3), and shows that the minimum sludge storage requirement for
the system is approximately 1.2 x 10° gal (4.54 x 10° 1), which repre-
sents 84 days of sludge volume storage. The project designer should in-
crease the minimum storage requirement by a safety factor of 20 to 50
percent to cover years with' unusual weather and other contingencies fac-
tors.
Even more accurate approaches can be taken to calculating required
sludge storage volume. For example, if open lagoons are used for sludge
storage, the designer can calculate volume additions resulting from pre-
cipitation, and volume subtractions resulting from evaporation from the
storage lagoon surface.
10-30
-------
a . 0
S.O '
X
a
s
N
-I
O
4..0-
S
_J
a
> 3 . 0'
3
!£ 2.0
S
=3
"1.0
TOTAL ANNUAL SLUDGE
VOLUME GENERATED
LINE A
CUMMULATtVE SLUDGE
VOLUME GENERATED 'x'
BY THE POTW
SLUDGE
STORAGE
VOLUME
REQUIRED
1 .2
LINE 3
CUMMUUATIVE SUUOG5
VOLUME APPLIED TQ
THE SLUOGS APPLICATION
SITE (5)
LINE C, SAME SLOPE
AS LINE A, LOCATE
TANGENT TO LINE B
M J J
MONTHS
METRIC CONVERSION
1 GAL = 3.73 i.
Figure 10-5.
Example of mass flow diagram using cumulative genera-
tion and cumulative sludge application to estimate
storage requirement.
10-31
-------
10.3.3 Location of Storage
Chapter 15, pages 15-4 through 15-58, of the EPA Process Design Manual
for Sludge Treatment and Disposal (16),, contains a comprehensive discus-
sion of sludge storage options and should be consulted for more details.
In general, the following factors in siting sludge storage facilities
should be considered:
Maximize use of potential storage in the existing sewage
treatment plant units. If the treatment plant has aerobic or
anaerobic digestion tanks, it is often possible to obtain sev-
eral weeks storage capacity by separating the digestor(s) to
increase solids content and increase surge storage. In addi-
tion, older POTW's often have phased out tanks, sludge drying
beds, etc., which are idle, and could be used for sludge stor-
age if properly modified.
If possible, locate long-term sludge storage facilities at the
POTW site because of the proximity of operating personnel ease
of vandalism control, and the possibility of sludge volume re-
duction during storage which will reduce transportation costs.
If the dedicated disposal site option is being utilized, the
long-term sludge storage facilities are often located at the
sludge application site. The sludge storage facility should
be located as far as possible on the site from residential and
other public access areas, since occasional odor problems
should be anticipated. The location of long-term sludge stor-
age facilities at sludge application sites which are privately
owned, e.g., farms, forestlands, etc., should be avoided. Ex-
perience has shown that problems such as odors, controlling
public access, etc., may create significant public relations
problems.
f Generally, minimize the number of times
handled, e.g., transferred, stored, etc.
each time the sludge is handled.
10.3.4 Storage Design
Storage capacity can be provided by:
the sludge must be
Costs are incurred
1.
2.
3.
4.
Stockpiles.
Lagoons.
Tanks, open
Digesters.
top or enclosed.
10.3.4.1 Stockpiles
Stockpiling is a process for
been stabilized and dewatered
the temporary storage of sludge that has
or dried to a concentration (about 20 to
10-32
-------
60 percent solids) suitable for mounding with bulldozers or loaders.
The sludge is mounded into stockpiles 2 to 5 m (6 to 15 ft) high, de-
pending on the quantity of sludge and the available land area. Periodic
turning of the sludge helps to promote drying and maintain aerobic con-
ditions. The process is most applicable in arid and semiarid regions,
unless the stockpiles are covered to protect against rain. Enclosure of
stockpiles may be necessary to control runoff. For more information on
stockpiling as a method of storage, see Chapter 15, Section 15.3.2.3, in
the Process Design Manual for Sludge Treatment and Disposal (16).
10.3.4.2 Lagoons
Lagoons are usually the least expensive way to store sludge. With proper
design, lagoon detention will also provide additional stabilization of
the sludge and reduce pathogens. Several types of lagoons have been
used for sludge storage, including:
Faculative Sludge Lagoons.
e Anaerobic Liquid Sludge Lagoons.
Aerated Storage Basins.
Drying Sludge Lagoons.
For details of each, see Chapter 15 in the Process Design Manual for
Sludge Treatment and Disposal (16).
10.3.4.3 Tanks
Various types of tanks can be used to store sludge. In most cases,
tanks are an integral part of the sludge treatment processes of the POTW
and their design includes storage capabilities. The three types dis-
cussed in Chapter 15 of the Process Design Manual for Sludge Treatment
and Disposal (16) include:
Imhoff and Community Septic Tanks.
Holding Tanks.
Unconfined Hoppers and Bins.
10.3.4.4 Treatment Plant Digester Capacity
Many sewage treatment plants do not have separate sludge retention capa-
J-vij-4- itstl w r\n r\r\ r»-f- -i r\tn c? r»-F -I- l*i£i rlTriQclr^r* wstl i imc» "For* c4"i*\ r» a no Ixftian
available,
city, but rely on portions of the digester volume for storage. When
an unheated sludge digester may provide short-term storage
capacity. In anticipation of periods when sludge cannot be applied to
the land, digester supernatant withdrawals can be accelerated to provide
storage for several weeks of sludge volume (17).
10.3.5 Cost Estimation Factors
Detailed cost information on
previously discussed can be
Sludge Treatment and Disposal
the different
found in the
(16).
types of storage facilities
Process Design Manual for
10-33
-------
10.4 Sludge-to-Land Application Methods
10.4.1 Current Status
The technique used to apply sludge to the land can be influenced by the
means used to transport the sludge from the POTW(s) to the land applica-
tion site(s). Commonly used methods include the following:
Same transport vehicle both hauls sludge from the POTW(s) to
application site(s) and applies sludge to land.
§ One type of transport vehicle, usually with a large volume ca-
pacity, hauls sludge from the POTW(s) to the application
site(s). At the application site(s) the sludge haul vehicle
transfers the sludge either to an application vehicle or into
a storage facility, or both.
Sludge is pumped and transported by pipeline from the POTW(s)
to a storage facility at the application site(s). Sludge is
subsequently transferred from storage facility(s) to sludge
application vehicle(s).
As a broad classification, sludge application methods involve either
surface or subsurface application. Each has advantages and disadvan-
tages which are discussed in the following subsections. In all of the
application techniques, the sludge eventually becomes incorporated into
the soil, either immediately by mechanical means or over time by natural
means.
As a second broad classification, sludge is applied either in liquid
form or in dewatered form. Methods and equipment used are different for
land application of these two sludge forms, and again each has advan-
tages and disadvantages which are highlighted in the specific following
subsections.
Application of sludge to land in liquid form is attractive because of
its simplicity. Dewatering processes are not required, and the liquid
sludge can be readily pumped. Liquid sludge application systems in-
clude:
t Vehicular surface application
- Tank truck spreading
- Tank wagon spreading.
Subsurface application
- Plow furrow or disking methods
- Subsurface injection.
10-34
-------
Irrigation application
- Spray application
- Gravity flooding.
10.4.2 Vehicular Application of Liquid Sludge
1.0.4.2.1 Vehicle Types Available:
Tables 10-10 and 10-11 describe the methods, characteristics, and limi-
tations of applying liquid sludge by surface application and subsurface
injection, respectively.
10.4.2.2 Vehicular Surface Application
Liquid sludge can be surface spread with application vehicles equipped
with splash plates, spray bars, or nozzles.
Uniform application is the most important criterion in selecting which
of the three attachments are best suited to an individual site. Figure
10-6 depicts a tank truck equipped with a splash plates. Figure 10-7
depicts a tank truck with a rear mounted "T" pipe. For these two meth-
ods, application rates can be controlled either by valving the manifold
or by varying the speed of the truck. However, a much heavier applica-
tion will be made from a full truck than from a nearly empty truck or
wagon unless the speed of the truck or wagon advancing across the field
is steadily decreased to compensate for the steadily decreasing hy-
draulic head (1). Figure 10-8 depicts a spray nozzle mounted on a tank
truck. By spraying the liquid sludge under pressure, a more uniform
coverage is obtained. ,
10.4.2.3 Subsurface Application
Soil incorporation (subsurface application) of liquid sludge has a num-
ber of advantages over surface application. Potential odor and other
nuisance problems can generally be avoided, nitrogen is conserved since
ammonia volatilization is minimized, and public acceptance may be bet-
ter. However, soil incorporation has a number of potential disadvan-
tages as well, compared to liquid sludge surface application: (1) it
may be more difficult to achieve even distribution of the sludge, (2)
for agricultural use the annual periods when sludge can be applied are
restricted to before planting and after harvesting crops, and (3) higher
fuel consumption (cost) are required for sludge application. Soil in-
corporation of sludge can be done in a number of ways. The principal
methods are subsurface injection and plow or disc cover.
Figures 10-9 and 10-10 illustrate equipment specifically designed for
subsurface injection of sludge. This equipment includes tank trucks
with special injection equipment attached. Tanks for the trucks are
generally available with 6,000, 7,500, and 11,000 1 (1,600, 2,000, and
10-35
-------
TABLE 10-10
SURFACE APPLICATION METHOD AND EQUIPMENT FOR LIQUID SLUDGES (4)
Method
Tank truck
Farm tank wagon
Characteristics
Capacity 500 to more than 2,000 gallons;
it is desirable to have flotation tires;
can be used with temporary irrigation
set-up; with pump discharge can achieve
a uniform application rate.
Capacity 500 to 3,000 gallons; it is desir-
able for wagons to have flotation tires;
can be used with temporary irrigation set-
up; with pump discharge can achieve a uniform
application rate.
Topographical and
Seasonal Limitations
Tillable land; not usable at'all times with
row crops or on very wet.ground.
Tillable land; not usable at all times
with row crops or on very wet ground.
Metric conversion factor:
1 gal « 3.78 1.
TABLE 10-11
SUBSURFACE APPLICATION METHODS, CHARACTERISTICS, AND LIMITATIONS
FOR LIQUID SLUDGES (9)
Method
Flexible irrigation hose
with plow or disc cover
Tank truck with plow or
disc cover
Farm tank, wagon with
plow or disc cover
Subsurface injection
Characteristics
Use with pipeline or tank truck with pressure dos-
discharge; hose connected to manifold discharge on
plow or disc.
500-gal commercial equipment available; sludge
discharge in furrow ahead of plow or disk mounted
on rear on 4-wheel-drive truck.
Sludge discharged into furrow ahead of plow mounted
on tank trailer; application of 170 to 225 wet tons/
ac; or sludge spread in narrow band on ground
surface and immediately plowed under; application
of 50 to 120 wet tons/acre.
Sludge discharge into channel opened by a chisel
tool mounted on tank truck or tool bar; application
rate 25 to 50 wet tons/ac; vehicles should not
traverse injected area for several days.
Topograhic and
Seasonal limitations
Tillable land; not usable
on very wet or frozen
ground.
Tillable land; not usable
on very wet or frozen
ground.
Tillable land; not usable
on very wet or frozen
ground.
Tillable land; not usable
on very wel: or frozen
ground.
Metric conversion factors:
1 gal 3.78 1
I ton/ac = 2.24 mt/ha.
10-36
-------
Figure 10-6. Splash plates on back of tanker truck (17).
Figure 10-7. Slotted T-bar on back of tanker truck (17).
10-37
-------
Figure 10-8. Tank truck with side spray nozzle for liquid sludge
surface application (17).
10-38
-------
Figure 10-9. Tank truck with liquid sludge tillage injectors
(courtesy of Rickel Mfg. Co.).
Figure 10-10. Tank truck with liquid sludge grassland injectors
(courtesy of Rickel Mfg. Co.),
10-39
-------
3,000 gal) capacities. Figure 10-11 shows another type of unit, a trac-
tor with a rear mounted injector unit. Sludge is pumped from a storage
facility to the injector unit through a flexible hose attached to the
tractor. Discharge flow capacities of 570 to 3,800 1/min (150 to 1,000
gpm) are used. The tractor requires a power rating of 40 to 60 hp.
It is usually not necessary to incorporate (inject) liquid sludge into
the soil when the sludge is applied to existing pasture or hay fields;
however, injection systems are available that can apply liquid sludge to
these areas with a minimum of crop and soil disturbance (see Figure 10-
10).
The plow or disc cover method involves discharging the sludge into a
narrow furrow from a wagon or flexible hose linked to a storage facility
through a manifold mounted on the plow or disc, which immediately covers
the sludge with soil. Figure 10-12 depicts a typical tank wagon with an
attached plow. These systems seem to be best suited for high loading
rates, i.e., a minimum of 3.5 to 4.5 mt/ha (8 to 10 dry T/ac) of 5 per-
cent slurry (9).
10.4.3 Vehicle Application of Dewatered Sludge
10.4.3.1 Vehicle Types Available
Spreading of dewatered sludge is similar to surface application of solid
or semisolid fertilizers, lime, or animal manure. Dewatered sludge can-
not be pumped or sprayed; spreading is done by box spreaders, bulldoz-
ers, loaders or graders, and then plowed or disked into the soil. The
box spreader is most commonly used, with the other three equipment items
generally being used only for high sludge application rates.
The principal advantages of using dewatered sludge are reduced sludge
hauling and storage costs, and the ability to apply higher sludge appli-
cation rates with one pass of the equiment. Potential disadvantages of
applying dewatered sludge are that, generally, substantial modification
of conventional spreading equipment is necessary to apply sewage sludge,
and more operation and maintenance is generally incurred in equipment
repairs as compared to many liquid sludge application systems. Table
10-12 describes methods and equipment for applying dewatered sludge to
the soil.
TABLE 10-12
METHODS AND EQUIPMENT FOR APPLICATION OF DEWATERED
SEMISOLID AND SOLID SLUDGES
Method Characteristics
Spreading Truck-mounted or tractor-powered box spreader (commercially
available); sludge spread evenly on ground; application rate
controlled by PTD and/or over-the-ground speed; can be in-
corporated by disking or plowing.
Piles Normally hauled by dump truck; spreading and leveling by
bulldozer or grader needed to give uniform application.
10-40
-------
^^^^^^»«lBl
-450C
-------
10.4.3.2 Surface Application
Figures 10-13 and 10-14 illustrate the specially designed trucks used to
spread dewatered sludge. For small quantities of dewatered sludge,
tractor-drawn conventional farm manure spreaders may be adequate (10).
Surface spreading of dewatered sludge on tilled land is usually followed
by incorporation of the sludge in the soil. It is not usually necessary
to incorporate dewatered sludge with the soil when the sludge is applied
to existing pasture or hay fields. Standard agricultural discs or other
tillage equiment pulled by a tractor or bull dozer can incorporate liq-
uid or dewatered sludge with soil. There are three different types:
disk tillers, disk plows, and disk harrows (Figures 10-15 and 10-16)
(13).
10.4.4 Cost Estimation Factors
Precise capital and operation and maintenance costs are difficult to es-
timate due to site specific variables. To obtain current cost informa-
tion, the various equipment manufacturers should be contacted. Typical
cost ranges (1982) of liquid and dewatered sludge hauling and spreading
trucks are shown in Table 10-13. ,
10.4.5 Irrigation Application '
Irrigation application of liquid sewage sludge has been accomplished
using spray irrigation and flood irrigation. Spray irrigation has been
used primarily for forest land sludge applications and occasionally for
application of sludge to dedicated land disposal site". Flood irriga-
tion of sludge has generally not been successful, and is usually dis-
couraged by regulatory agencies.
10.4.5.1 Spray Application
Spray irrigation application has been used to disperse liquid sludges on
clearcut openings, dedicated land disposal sites, and in forest stands.
Liquid sludges are readily dispersed by use of properly designed equip-
ment. Sludge solids must be relatively small and uniformly distributed
throughout the sludge in order to achieve uniform application and to
avoid system clogging. A typical spray application system consists of
the use of a rotary sprayer (rain gun) to disperse the liquid sludge
over the application site. The sludge, pressurized by a pump, is trans-
ferred from storage to the sprayer via a pipe system. Design of the
system can be portable or permanent and either moving or stationary.
Available spray irrigation systems include (10):
1. Solid set, both buried and above ground.
2. Center pivot.
3. Side roll.
4. Continuous travel.
5. Towline laterals.
6. Stationary gun.
7. Traveling gun.
10-42
-------
Figure 10-13. 7.2 cubic yard dewatered sludge spreader (courtesy
of Big Wheels Inc.).
Figure 10-14,
Large dewatered sludge spreader (courtesy of BJ
Mfg. Co.).
10-43
-------
Figure 10-15. Example of disc tiller.
Figure 10-16. Example of disc plow.
10-44
-------
TABLE 10-13
APPROXIMATE 1982 LIST PRICES FOR SLUDGE
HAULING AND SPREADING TRUCKS
(TELEPHONE SURVEY, DECEMBER 1982)
LIQUID SLUDGE
Capacity (Gal]
1,600,
2,000^
3,000
3,500
4,000
6,000
Base Price Range
($1.000)
60-80
80-90
. 90-105
110-130 ' '
120-140
130-160 '
Price Range with Typical
Sludge Accessories (Sl.OOO)
65-85
85-100
95-115
120-140
130-150
140-175
DEWATERED SLUDGE
Capacity (yd3)
Base Price Range
($1.000)
Base Price Range with
Typical Sludge Accessories
($1.000)
7
9
10
15
17
18
25
36
60-70
70-80
80-100
100-130
130-150
150-160
150-180
180-210
70-80
80-90
90-110
115-145
145-165
165-175
. 170-200
200-230
(a) The city of Seattle took bids for a specially equipped sludge applica-
tion truck for forest application in late 1982. Tank capacity is 2,000
gallons and truck is equipped with flotation tires,, articulated chassis,
sludge spray cannon with 120-ft range, and dozer blade. Cost was
$160,000.
Metric conversions:
1 gal = 3.
1 yd1* = 0.
1 ft = 0.305 m
781
765 nr
10-45
-------
The utility of these systems within the application site depends upon
the application schedule and management scheme utilized. All the sys-
tems listed, except for the buried solid system are designed to be port-
able. Main lines for systems are usually permanently buried. This pro-
vides protection from freezing weather and runover by heavy vehicles.
The proper design of sludge spray application systems requires through
knowledge of the commercial equipment available, and its adaptation to
use with liquid sludge. Few sludge spray irrigation systems are in use,
and these are generally associated with dedicated land disposal sites.
It is beyond the scope of this manual to present engineering design
data, and it is suggested that qualified irrigation engineers and expe-
rienced irrigation system manufacturers be consulted.
Figures 10-17, 10-18, and 10-19 illustrate a few of the systems listed.
Table 10-14 presents a cost comparison of the most widely used spray ir-,
rigation systems, in terms of. characteristics important to sludge appli-
cation. < , ;.'.. '. ' "';' ' '".. '-,.,«. -, - .,.;,,.
-1- TABLE 10-14 " .
APPROXIMATE CAPITAL COST OF DIFFERENT
SPRINKLER SYSTEMS (12)
Type of System
Portable solid set*
Buried solid set
Side wheel roll
Traveling gun
Center pivot
Approximate
Cost ($/ac)f
540
, 540
130
160
' 240
- 1,200
- 1,'350
-400
- 340
- 470 "
Size of Single
System (ac)
No
No
20
40
40
limit
limit
- 80
- 100
>- 160
Labor Required
(hr/ac Irr.)
0.20
0.05
0.10
0.10
"0.05-
- 0.50
- 0.10
- 0.30
- 0.30
-,0.15
* Towline lateral system is same, except that'field shape is not as flexible.
t Does not include cost of water supply, pump, 'power unit, and-mainline.
- ' . i <',''
xx Costs are updated to 1980. ' : , i
Metric conversion factor: '''.'.'' , , " ',
ac = 0.4047 ha.
1 ' , ', '"'., »
! ' " . -
10.4.5.2 Gravity Irrigation
-' &*
In general, }and application by gravity'-flooding of sludge has not been
successful where attempted, and is discouraged by regulatory agencies
and experienced designers. Problems1 arise from (1) .difficulty in
achieving uniform sludge application'rates,, (2) clogging, of soil pores,
and (3) tendency of the sludge to turn septic with resulting odors.
10-46
-------
Figure 10-17. Center pivot spray application system (courtesy of
Valmont Ind. Inc.).
Figure 10-18. Traveling gun sludge sprayer (courtesy of Lindsay
Mfg. Co.).
10-47
-------
IRRIGATION
GUN & STAND
BOOSTER
PUMP
3" BALL VALVE
PRIMARY
PUMP
TEMPORARY
HOLDING
POND
4" PIPELINE 3" LEVER ACTION 5" PIPELINE MESH.
VALVE (2) STRAINER
PLASTIC LINER
(AS REQUIRED BY REGULATIONS)
Figure 10-19. Diagram of liquid sludge spreading system in
forest land utilizing temporary storage ponds (19)
10-48
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10.5 Site Preparation
10.5.1 General
In general, for agricultural sludge utilization systems where sludge is
applied to privately owned farms at low agronomic application rates,
site modifications are not typically cost effective. At forested sys-
tems, there is usually much more forest land available within the local
area than is needed for sludge application, so unsuitable land can be
avoided, not modified.
In the case of sludge utilization for disturbed land reclamation, it is
common that extensive site grading and soil preparation is necessary.
However, these site preparation costs are usually borne by the land
owner (e.g., mining company, ore processor, etc.), and not by the muni-
cipality (see Chapter 8 for discussion).
Extensive sludge application site modification and improvement costs may
be acceptable to the municipality only where the dedicated land disposal
site option is being utilized for high rate sludge application over long
periods of time, since the costs can be amortized over many years of ap-
plication site life.
The site improvements for OLD systems will require:
Topographic map, scale of 1:1200 or less, with contour inter-
vals of 0.6 m (2 ft) or less.
Soil map.
Drainage map.
t Ground water or piezometric contour map.
0 Drawing showing location of existing structures.
Knowledge of design criteria imposed by (1) regulatory require-
ments (2) proposed sludge transport and application methods,
(3) size and location of buffer areas needed, (4) application
site sludge storage requirements, and (5) off-site access
roads.
10.5.2 Grading
The purpose of establishing surface grades is to ensure that runoff
water and/or liquid sludge do not pond. Emphasis in planning is given
to filling depressions with soil from adjoining ridges and mounds. If an
excessive amount of filling is required for low places, or if sufficient
soil is not readily available, field ditches can be installed and the
surfaces warped towards them (14). In areas with little or no slope,
grades can be established or increased by grading between parallel
ditches with cuts from the edge of one ditch and fills from the next.
10-49
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Terraces may be needed to protect lower lands from surface flows. These
are generally dug across a slope, or at the toe of a slope with the bor-
row material diked on the lower side for efficient use of the material.
Diversion terraces are generally graded and grass covered so that the
collected water may be delivered at non-erosive flows to a control dis-
charge point.
10.5.3 Subsurface Water Control
See Chapter 9, Section 9.7.7, for information on subsurface drain con-
struction which may be used to prevent ground water pollution.
10.5.4 Cost Estimation Factors
Site preparation costs are very site-specific, and the information pro-
vided in this section is only presented as an example.
10.5.4.1 Dike Costs
The following assumptions were made for the designed dike;
(a) Dikes consist of a 1.2 m (4 ft) wide clay core surrounded by
granular borrow.
(b) Borrow is available on site, while clay is purchased off-site,
(c) Compaction in 20 cm (8 in) lifts.
(d) Material amounts to be purchased are measured as installed and
compacted volumes.
(e) Dike is 1.2 m (4 ft) high with 2:1 side slopes.
Construction cost for a dike such as described above. (1982 dollars)
would range from $13 to $20 per linear m ($4 to $6 per linear ft) of
dike length in most parts of the country. In terms of area, if dikes
are constructed at 18 m (60 ft) intervals, the cost of dike construction
is about $8,650/ha ($3,500/ac).
10.5.4.2 Dike Costs
The following assumptions were made for this example:
Assumptions: l
1. Borrow pit for soil material is located on site.
2. Compaction in 30 cm (12 in) lifts to 95 percent compaction.
3. Berm is 1 m (3 ft) high with 2:1 side slopes. .
The cost (1980 dollars of berm as described would be about $3,50/m^
(2.70/yd-3), or $52.50 per linear m ($16 per linear ft) of berm.
10-50
-------
,.,,...",.- ;, ,1 0,5,, 4. 3 Site Gracing Costs ...,,..
The following ^assumptions are made for, site grading:
, '.' ;1. , AH soil .moved is on site. , ,
2. Minimum number of trees.
3. No rock blasting necessary.
4.
Average of 3,000 >3/ha (1» 5^3 yd3/ac) of dirt is moved and
graded, e.g., an average of 0.3 m (1 ft) of depth.
The costs (1980 dollars) for clearing'and grubbing will be approximately
$2»22,0/ha ($900/ac).. Grading will cost approximately $1.30/m3 ($1.20/
yd3),' or $4,700/ha ,($l,900/ac) using the assumptions listed above.
Total rough estimate costs for grading is $6,900/ha ($2,800/ac). If the
topography is highly irregular, grading costs can greatly exceed this
estimate. For example, a city in Texas spent ten times the estimate
above to grade a dedicated land disposal site located on drastically
disturbed, highly eroded soil.
10.6 Supporting Facilities Design
Th,e,cost of .supporting facilities, such as permanent all-weather access
roads, fences,' etc. , can normally only be justified for high rate sludge
application sites which will be used , over a long project life. They are
rarely applicable to privately owned agricultural sludge utilization
sites.
10.6.1 Access Roads
A permanent road should be provided from the public road system to dedi-
cated land disposal sites. For large sludge application sites, the
roadway' should be"- 6. '5 to 8 m (20 to 24 ft) wide for two-way traffic; for
smaller sites, a 5 m (15 ft) wide road should suffice. To provide, "at 1
'Weat;her access, the roadway, as a minimum, should be gravel surfaced.
"Asphalt pavement* is preferable. Grades should not exceed equipment lim-
itations. For loaded vehicles, uphill grades should be less than 7 per-
cent. ,....-.,.
10.6.2 Site Fencing and Security .....
Access to dedicated land sludge disposal sites should be limited to one
or two entrances that have gates which can be locked when the site is
unattended. Depending on the topography and vegetation on the site and
adjoining areas', entrance gates may suffice to prevent unauthorized ve-
hicular access. At some sites, it is necessary to construct peripheral
fences to restrict trespassers a'nd animals.
10-51
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Fencing requirements are influenced by the relative isolation of the
site. Sites close to residences require fencing. Facilities that are
in relatively isolated rural areas, may require a less sophisticated
type of fence or only fencing at the entrance and other places to keep
unauthorized vehicles out.
To discourage vandalism and trespassing, a 2 m (6 ft) high chain link
fence topped with barbed wire guard is desirable. To screen the facil-
ity from view, a wood fence or hedge may be used (18). /
10.6.3 Equipment and Personnel Buildings
At larger facilities or where climates are extreme, buildings may be ne-
cessary for office space, equipment, and employee facilities. Since ap-
plication sites may be operated year around, some protection from the
elements for the employees and equipment may be necessary. Sanitary fa-,
cilities should be provided for both site and-hauling personnel. At
smaller facilities where buildings cannot be justified, trailers may be
warranted (18). ;"-',., '
10.6.4 Lighting and Other Utilities
If application operations occur at night, portable lighting should be
provided at the operating area. Lights may be affixed to haul vehicles
and on-site equipment. These lights should be situated to provide illu-
mination to areas not covered by the regular headlights of the vehicle.
If the facility has structures (employee facilities, office buildings,
equipment repair or storage sheds), or if the access road is in continu-
ous use, permanent security lighting may be needed.
Larger sites may need electrical, water, communication, and sanitary
services. Remote sites may have to extend existing services or use ac-
ceptable substitutes. Portable chemical toilets can be used to avoid
the high cost of extending sewer lines; potable water may be trucked in;
and an electrical generator may be used instead of having power lines
run on site.
Water should be available for drinking, dust control, washing mud from
haul vehicles before entering public roads, and employee sanitary facil-
ities. Telephone or radio communications may be necessary since acci-
dents or spills can occur that necessitate the ability to respond to
calls for assistance (18).
10.6.5 Cost Estimation Factors
10.6.5.1 Road Construction Costs
Road construction costs vary widely depending upon local conditions.
Typical 1980 costs for rough estimating purposes are given below.
10-52
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Cleaning and grubbing, $1.72/m2 ($0.16/ft2).
Grading and compacting subbase, $2.15/m2 ($0.20/ft2).
Base Material, in-place, 30 cm (12 in), $6.45 m2 ($0.60/ft2).
Wear coarse material, 10 cm (4 in) crushed stone, $3.00/m2
Bituminous paving, 7.5 cm (3 in), $5.38/m2 ($0.80/ft2).
Miscellaneous drainage culverts, etc., $5.38/m2 ($0.50 ft2).
Typical 1980 costs for an all w&ather road are the total of the above,
which equals $27.55/m^ ($2.50/ft^). If a 8 m (24 ft) wide all weather
road is constructed, the cost is aproximately $186,000/km ($300,000/mi).
A 5 m (15 ft) wide all weather road is approximately $124,000/km
($200,000/mi).
A less expensive, gravel only road can be constructed for approximately
40 percent of the above costs for a bituminious paved road.
10.6.5.2 Fence Construction Costs
Typical 1980 unit costs of installed fences are approximately as fol-
lows:
t Two m (6 ft) high chain link with barb wire topping strands is
$33/1inear m ($10/1inear ft), plus $900 for each gate.
Other types of fences range in cost from $16 to $40/lirrear m
($5 to $12/linear ft).
10.6.5.3 Lighting Costs
Typical 1980 lighting costs for fixed pole mounted lights of various
types are as follows:
Mercury vapor, $415 for 400 watt; $520 for 1000 watt.
Metal halide, $455 for 400 watt; $595 for 100 watt.
High pressure sodium, $490 for 400 watt; $720 for 1000 watt.
10.6.5.4 On-Site Structure Costs
Typical 1980 structural costs for rough estimation purposes are as fol-s
1ows: '
t Office type structure, $590/m2 ($55/ft2).
a Maintenance/warehouse type structure, $330/m2 ($31/ft2).
10-5.3
-------
Trailers cost approximately $430/m2 ($40/ft2), or rent for approximately
$43/m2/month ($0.40/ftVmonth).
10.6.5.5 Ground Water Monitoring Costs
In many cases, regulatory agencies will require monitoring of ground
water quality beneath and adjacent to sludge to land application sites.
Typical 1980 costs for monitoring well construction are as follows:
t Well material and construction, $106/m ($32/ft) of depth.
Sampling pump and accessories, $1,700 each.
Typical 1980 costs for sampling and analysis are approximately
$200/sample.
A typical monitoring installation may have four monitoring wells 9 m (30
ft) deep, and be sampled four times annually. In such a situation, mon-
itoring capital cost would be approximately $10,600.
10.6.5.6 Other Monitoring Costs
Monitoring costs involved in sludge, soil, and plant analyses can be es-
timated by contacting local commercial laboratories that can conduct the
analyses required.
10.7 References
1.
Anderson, R. K., B. R. Weddle, T. Hillmer, and A. Geswein. Cost of
Land Spreading and Hauling Sludge From Municipal Wastewater Treat-
ment Plants - Case Studies. EPA-530/SW-619, U.S. Environmental
Protection Agency, Office of Solid Waste Management Program, Wash-
ington, D.C., October Ohio, 1977. 149 pp. (Available from Na-
tional Technical Information Service, Springfield, Virginia, PB-274
875)
2.
Hill. Wastewater Solids Process, Transport, and Disposal/Use
Systems Task Report. Oakland, California, 1977. 156 pp.
CH2M
Cooley, J. H. Applying Liquid Sludge to Forest Land: A Demonstra-
tion. Proceedings of the Fifth Annual Madison Conference of Ap-
plied Research and Practice on Municipal and Industrial Waste,
September 22-24, 1982. University of Wisconsin, Madison, Wiscon-
sin. 9 pp.
Cunningham, 0., and M. Northouse. "Land Application of Liquid Di-
gested Sewage Sludge (METROGRO) at Madison, Wisconsin." Seminar
Proceedings, "Land Application of Sewage Sludge." Virginia Water
Pollution Control Association, Inc., Richmond, Virginia, October
29, 1981. pp. 111-145.
10-54
-------
5. Ettlich, VI. F. Transport of Sewage Sludge. EPA-600/2-77-216,
Culp/Wesner/Culp, El Dorado Hills, California 1977. 85 pp.
(Available from National Technical Information Service, Spring-
field, Virginia, PB-278 195)
6. Ettlich, W. F. What's Best for Sludge Transport? Water Wastes En-
gin., 13(10);20-23, 1976.
7. Gorte, J. K. Cost of Forest Land Disposal of Sludge. Ph.D. The-
sis, Michigan State University, 1980. 196 pp.
8. Haug, R. T., L. D. Tortorici, and S. K. Raksit. Sludge Processing
and Disposal.
282 pp.
LA/OMA Project, Whittier, California, April 1977.
10.
11.
12.
13.
14.
15.
16.
Keeney, D. R., K. W. Lee, and L. M. Walsh. Guidelines for the Ap-
plication of Wastewater Sludge to Agricultural Land in Wisconsin.
Technical Bulletin No. 88, Wisconsin Department of Natural Re-
sources, Madison, 1975. 36 pp.
Loehr, R. C., W. J. Jewell, J. D. Novak, W. W.
Friedman. Land Application of Wastes. Vol. 2.
hold, New York, 1979. 431 pp.
Clarkson, and G. S.
Van Nostrand Rein-
Metcalf and Eddy.
Reuse. McGraw-Hill,
Wastewater Engineering:
New York, 1979. 920 pp.
Treatment, Disposal,
Pound, C. E., and R. W. Crites. Wastewater Treatment and Reuse by
Land Application. Vol. 2. EPA-660/2-73-006b, Metcalf and Eddy,
Palo Alto, California, August 1973. 249 pp. (Available from Na-
tional Technical Information Service, Springfield, Virginia, PB-225
941)
Phung, H. T. , L. K. Barker, D. E. Ross, and D. Bauer. Land Culti-
vation of Industrial Wastes and Municipal Solid Wastes: State-of-
the-Art Study, Volume 1. EPA-600/2-78-140a, SCS Engineers, Long
Beach, California, October 1978. 220 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-287 080)
Land.
pp.
U.S. Soil Conservation Service. Drainage of Agricultural L
Water Information Center, Port Washington, New York, 1973. 430
U.S. Environmental Protection Agency, Municipal Construction Divi-
sion. Evaluation of Land Application Systems. EPA-430/9-75-001,
Washington, D.C., March 1975. 182 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-257 440)
U.S. Environmental Protection
Sludge Treatment and Disposal.
ington, D.C. September 1979.
Agency. Process Design Manual for
EPA 625/1-79-011. MERL, ORD, Wash-
10-55
-------
17. U.S. Environmental Protection Agency. Sludge Treatment and Dis-
posal, Volume 2. Contract No. EPA-625/4-78-012. Cincinnati, Ohio,
1978. 155 pp.
18. U.S. EPA. Process Design Manual: Municipal Sludge Landfills. EPA-
625/1-78-010. October 1978. 331 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-279 675)
19. Water Pollution Control Federation. Design of Wastewater and
Stormwater Pumping Stations. Manual of Practice FD-4. Water Pol-
lution Control Federation, Washington, D.C., 1981. 152 pp.
20. Water Pollution Control Federation. Wastewater Treatment Plant De-
sign. Lancaster Press Company, Lancaster, Pennsylvania, 1977. 560
pp.
10-56
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CHAPTER 11
OPERATION AND MANAGEMENT
11.1 General
For all systems, a planned operation and management program should be
prepared (many state regulatory agencies require such a plan) and re-
sponsibility clearly defined for its implementation. Essential elements
of the operation and management program include the following:
t Operations at the POTW to ensure that the treated sludge is
adequately stabilized and monitored to meet the requirements
for land application.
Flexible scheduling of sludge transport, storage, and applica-
tion activities to allow for both the need of the POTW to re-
move sludge, and the ability to apply the sludge to the land
application site(s).
Design, operation, management, and maintenance of the sludge
transport system to minimize potential nuisance and health
problems. Included should be an in-place procedure for rapid
response to accidents, spills, and other emergency conditions
arising during routine sludge transport operations.
Design, operation, management, and maintenance of the sludge
application site(s) and equipment to minimize potential nui-
sance and health problems. Where privately owned and operated
land is involved (e.g., farms, commercial forest land, mined
lands, etc.), the owner/operator is a key participant in the
overall application site management and operation program.
« Monitoring and Reporting - monitoring of sludge generation and
analyses of sludge, soil, plant, surface water, and ground
water as needed for compliance with stipulations, standards,
and regulatory requirements. The extent of monitoring re-
quired will vary greatly depending on the sludge application
rate and location.
Recordkeeping - adequate documenting of program activities,
monitoring, etc.
Health and Safety - necessary steps must be routinely employed
to protect the general public, operations personnel, etc.
11.2 Nuisance Issues
Minimizing adverse aesthetic impacts of a sludge land application system
will aid in maintaining public acceptance of the project. Continuous
11-1
-------
efforts should be made to avoid or reduce nuisance problems associated
with sludge hauling, application, and related operations (13). Poten-
tial nuisances of concern include noise, odor, spillage, mud, and dust.
11.2.1 Odor
All sludge management systems must consider objectionable odor as a po-
tential problem. Objectionable odors could result in an unfavorable
public reaction and reduced acceptance of land application options. Po-
tential for odors can be reduced or eliminated:
Proper sludge stabilization at the POTW, and a defined proce-
dure for managing sludge which is not properly stabilized,
e,,g., additional treatment, alternate disposal means, etc.
Incorporation of sludge as soon as possible after delivery and
application to the site.
t Daily cleaning (or more frequently, if needed) of trucks,
tanks, and other equipment.
Avoiding sludge application to waterlogged soils, or other
soil or slope conditions which would cause ponding or poor
drainage of the applied sludge.
Use of proper sludge application rates for application site
conditions.
Avoiding or limiting the construction and use of sludge stor-
age facilities at the land application site(s), or designing
and locating the sludge storage facilities to prevent odor
problems. Experience has shown that sludge storage facilities
are a major cause of odor problems at land application sites.
t Subsurface injection of sludges. After subsurface injection,
the soil should not be disturbed for several weeks, if possi-
ble; a second tillage operation a few days later may cause
odors.
Isolation of the sludge application site(s) from residential,
commercial, and other public access areas.
Prevention of odor problems using the recommendations listed above is
important to public acceptance of land application programs. If, and
when, odor problems resulting in citizen complaints do occur, the proj-
ect management should have established procedures for correcting the
problems and responding to complaints.
11-2
-------
11.2.2 Spillage
All trucks involved in handling sludge over highways and streets should
be designed to prevent sludge spillage. Liquid sludge tankers generally
do not present a problem. For sludge slurries (10 to 18 percent solids)
specially designed haul vehicles with anti-spill baffles have been ef-
fectively employed. Sludge spillage on-site can generally also be best
controlled using vacuum transfer systems. If mechanical or human errors
during, transport, or at the application site do result in spillage of
sludge, cleanup procedures should be employed as soon as possible.
11.2.3.: Mud
Both tracking of mud from the field on to highways, and field or access
road rutting by sludge transport or applicator equipment are nuisance
concerns. Mud can be a particularly severe problem in areas with poor
drainage, but can occur at any site during periods of heavy rain or
spring thaws. To minimize these problems, the following management
steps should be considered.
Choose all-weather site access roads or modify access roads
with gravel or other acceptable weight-bearing material.
Use vehicles with flotation tires.
t Use vehicles with smaller capacity or temporarily reduce vol-
ume of sludge being hauled.
0 Mud tracked on roads should be removed.
0 Vehicles should be washed down regularly when moving between
sites to prevent tracking of mud on highways. This process
also improves the public image of sludge hauling and handling
systems and improves continued community acceptance.
11.2.4 Dust
Dust movement off-site is enhanced by wind or the movements of haul ve-
hicles and equipment. To minimize dust generation, access roads may
need to be graveled, paved, oiled, or watered.
11.2.5 Road Maintenance
The breakup of roads by heavy sludge hauling vehicles can be a problem,
particularly in northern climates, and can cause public complaints.
Project management should,make provisions to repair roads or to have a
fund available to help finance cost of road repairs resulting from proj-
ect activity.
11-3
-------
11.2.6 Selection of Haul Routes
Routes for sludge haul trucks should avoid residential areas to prevent
nuisance caused by truck and air brake noise, dangers to children, and
complaints because of frequency of hauling.
11.3 Safety Concerns
The safety of everyone involved in a sludge application program is of
paramount importance. This concern encompasses individuals working di-
rectly with sludge (POTW personnel, sludge haulers, farmers, heavy
equipment operators, etc), as well as persons living or working near an
application site, or who are visiting the site.
Safety features should be incorporated into every facet of the system
design. Certain practices should be followed routinely to assure safe
working conditions. An official operations plan should be adopted,
which contains specific safety guidelines for each operation and feature
of the system.
The operation of sludge hauling and application equipment presents the
greatest potential for accidents. Equipment should be operated only by
fully trained and qualified operators. Regular equipment maintenance
and operational safety checks should be conducted.
The stability of the soil can present a potential safety problem, par-
ticularly when operating large equipment. Vehicles should approach dis-
turbed or regraded sites, muddy areas, or steep slopes cautiously to
prevent tipping or loss of control.
As with any construction activity, safety methods should be implemented
in accordance with OSHA (Occupational Safety and Health Act of 1979)
guidelines. In accordance with OSHA guidelines, the following precau-
tions and procedures should be employed for sludge land application
projects:
A safety manual should be available for use by employees
they should be trained in all safety procedures.
and
Appropriate personal safety devices such as hardhats, gloves,
safety glasses, and footwear should be provided to employees.
Appropriate safety devices, such as rollbars, seatbelts, audi-
ble reverse warning devices, and fire extinguishers, should be
provided on equipment used to transport, spread, or incorpo-
rate sludge.
Fire extinguishers should be provided for equipment and build-
ings.
11-4
-------
Communications equipment should be available on site for emer-
gency situations.
Work areas and access roads should be well marked to avoid on-
site vehicle mishaps.
Adequate traffic control should be provided to promote an
orderly traffic pattern to and from the land application site
to maintain efficient operating conditions and avoid traffic
jams on local highways.
Public access to the sludge application site(s) should be con-
trolled. The extent of the control necessary will depend on
the sludge application option being used, time interval since
sludge was last applied, and other factors. See the appropri-
ate discussion in the applicable process design chapters (6
through 9) for the sludge application option being considered.
In general, public access to dedicated disposal sites should
be controlled at all times, while public access to application
sites using other land application options should be con-
trolled during sludge application operations and for an appro-
priate time period after the sludge is applied.
11.4 Health Concerns
11.4.1 General
A detailed discussion of pathogens and vectors which may be associated
with sewage sludge is contained in Appendix A. Although bacteria,
viruses, and parasites are generally present in sludge, studies con-
ducted through 1982 by the EPA, and others, have shown no significant
health problems for personnel who experience regular contact with sewage
sludge at POTW's and/or sludge to land application sites (25)(28). Fur-
thermore, epidemiological studies have shown no significant health prob-
lems to humans associated with living or working in proximity to sites
receiving land application of. sludge or wastewater (26)(27). This
health effects research is continuing in attempting to fully document
any potential health risks involved in direct or incidental contact with
sewage sludge.
11.4.2 Personnel Health Safeguards
Project management should include health safeguards for personnel in-
volved with sludge transport and handling, as follows:
t Receive regular typhoid and tetanus inoculations and poliovi-
rus and adenovirus vaccinations.
Limit direct contact with aerosols as much as possible where
liquid sludge application techniques are used.
11-5
-------
Encourage proper personal hygiene.
Provide annual employee health checkups.
Record reported employee illnesses, and if a pattern (trend)
develops of illnesses potentially associated with sludge path-
ogens, investigate and take appropriate action.
11.5 Monitoring
11.5.1 General
Sampling and analysis methods for sludge, surface
soil, and crops are covered in Appendix C. This
the need for monitoring and frequency of sampling.
11.5.2 Sludge Monitoring
water, ground water,
section will discuss
As discussed in Appendix A, there may be a wide variation in sludge
physical and chemical characteristics between different POTW's, and, in
addition, there are seasonal variations in the characteristics of sludge
generated by a particular POTW. Therefore, analysis of the sludge on a
regular basis is necessary to know exactly what is being applied to the
land and to ensure acceptability of the sludge for land application, re-
gardless of the land application option that is being used. The analy-
tical data generated provide a quality control tool, a record of sludge
variability, and a warning of the presence of high concentrations of un-
desirable constituents. In addition, data on plant nutrients (N, P, and
K) are necessary to allow sludge users (e.g., farmers, commercial tree
growers, etc.) to make efficient use of nutrients and to calculate
sludge application rates.
The frequency of sludge
tion of the following:
sampling and analysis necessary will be a func-
System size; in general, the larger the system in terms of
sludge generated, the more frequently the sludge will be sam-
pled and analyzed. A very large system (e.g., serving a popu-
lation of over 200,000) may sample daily, while a small system
(e.g., under 5,000 population) may only sample sludge quar-
terly.
Historical variations in sludge characteristics; in general,
the greater the variability which has been found in sludge
physical and/or chemical characteristics, the more often the
sludge should be analyzed. Factors to be considered include
contributions of wastewater from seasonal industries, POTW
operational reliability, the dampening effect of large volume
sludge storage, and the "normal" quality of the sludge, i.e.,
how seriously will fluctuations in the sludge characteristics
affect the land application option feasibility?
11-6
-------
The land application option being utilized influences the
necessary frequency of sludge sampling. In general, options
which require accurate knowledge of sludge characteristics,
e.g., agricultural utilization, may require more frequent
sludge sampling than would an option not involving crop
growth, e.g., dedicated land disposal without crops.
An overriding factor usually is the sludge sampling frequency
required by the cognizant regulatory agency.
The sludge parameters analyzed will also vary depending on the factors
listed above, e.g., system size, historical sludge variability, type of
land application option used, and regulatory agency requirements. Gen-
erally, as a minimum, sludge will be analyzed for pH, percent solids, N,
P, K, and the heavy metals. In addition, if the system used is poten-
tially sensitive to pathogens and/or priority organics these parameters
may also be measured.
11.5.3 Soil Monitoring
The need for soil monitoring depends on the site characteristics and the
sludge application option being utilized. Each of the design chapters
discusses soil monitoring needs for the specific option being covered.
In general, routine annual soil tests will provide the data required for
monitoring purposes.
11.5.4 Vegetation Monitoring
Periodic analysis of the harvested portions of crops grown on the
sludge-treated soil will aid in preventing accumulation of potentially
phytotoxic materials. Vegetation monitoring will also signal the ap-
proach of increased levels well in advance of permanent damage to either
soil or crop (15). Plants can also serve as effective indicators of ex-
cessive or insufficient levels for many soil constituents.
The need for, and frequency'-'of, vegetation monitoring will vary depend-
ing on system specific factors. Generally, if sludge is applied at low,
agronomic rates there is little need to sample and analyze the vegeta-
tion. If, however, sludge is being applied at high rates (e.g., dedi-
cated land disposal with crop growth), the crop should be tested prior
to harvesting for human or animal consumption. Tables in Appendix C
provide suggested crop monitoring parameters and sampling procedures.
11.5.5 Ground Water Monitoring
Appendix C includes a discussion of ground water monitoring procedures.
If ground water monitoring is needed, a hydrogeologist should be con-
sulted during the initiation and implementation of a ground water moni-
toring program. Detailed ground water monitoring procedures can also be
found in Reference (24).
11-7
-------
Systems which apply sludge at low rates for agriculture generally do not
monitor ground water quality. Conversely, dedicated land disposal sites
are usually required to monitor ground water quality by the cognizant
regulatory agency. If the forest land or land reclamation option is
being utilized, ground water monitoring will probably be required for
these application sites which could affect sensitive aquifers, e.g., the
decision- is made on a case-by-case basis by the operating agency and/or
regulatory agency.
11.5.6 Surface Water Monitoring
Appendix C includes a section on surface water monitoring procedures.
11.6 Recordkeeping
Operational and monitoring data may be required by local, state, and/or
federal regulatory agencies. Consequently, any municipality implement-
ing a sludge application system, should develop an adequate recordkeep-
ing program.
Management and reporting activities may include equipment use and main-
tenance records, performance records, required regulatory reports, cost
records, and public relations activities (e.g., complaints). These rec-
ords can also be used as the basis for scheduling site development and
gauging the efficiency of operations.
Records on the sludge application portions of the program should contain
at least the following:
Sludge
tions.
characteristics and amounts applied to specific loca-
Major operational problems, complaints, or difficulties.
Qualitative and/or quantitative data related to the operation
of the land application site, including ground and surface
water, soils, and crops.
Figure 11-1 depicts the sampling and analytical data form used by Defi-
ance, Ohio. They utilize a map for the application area (Figure 11-2).
The coding of each field allows the equipment operator to record the lo-
cation and quantity of sludge applied on a daily basis. Figure 11-3 de-
picts the daily log sheet identifying sludge distribution information
with specific land areas used in conjunction with this program.
Agricultural utilization projects must also be concerned about cumula-
tive metal loadings. This type of data should be maintained on a regu-
larly scheduled basis to provide an early warning when cumulative metal
loadings begin to approach the recommended maximum levels.
11-8
-------
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11-11
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11.7 References
1. U.S. EPA. Process Design Manual: Municipal Sludge Landfills. EPA-
625/1-78-010, October 1978. (Available from National Technical In-
formation Service, Springfield, Virginia, PB-279 675)
2. Blakeslee, P.A. Site Monitoring Considerations. In: Application
of Sludges and Wastewaters on Agricultural Land: A Planning and
Educational Guide, B.D. Knezek and R.H. Miller, Eds. Ohio Agricul-
tural Research and Development Center, Wooster, Ohio, 1976. pp.
11.1-11.5.
3. U.S. EPA. Process Design Manual For Land Treatment of Municipal
Wastewater. EPA 625/1-77-008, October 1977. pp. 5.94-5.99.
(Available from National Technical Information Service, Springfield,
Virginia, PB-299 655)
4. Loehr, R.C., W.J. Jewell, J.D. Novak, W.W. Clarkson, and 6.S. Fried-
man. Land Application of Wastes. Vol. 2. Van Norstrand Reinhold,
New York, 1979. 431 pp.
5. U.S. EPA. Process Design Manual for Sludge Treatment and Disposal.
EPA 625/1-79-011. Center for Environmental Research Information,
Cincinnati, Ohio, September 1979. (Available from National Techni-
cal Information Service, Springfield, Virginia, PB80 200546)
6. U.S. Environmental Protection Agency. Municipal Sludge Management:
Environmental Factors. EPA 430/9-77-004, Washington, D.C., 1977. 30
PP.
7. Keeney, D.R., K.W. Lee and L.M. Walsh. Guidelines for the Applica-
tion of Wastewater Sludge to Agricultural Land in Wisconsin. Tech-
nical Bulletin 88. Wisconsin Department of Natural Resources, Madi-
son, 1975. 36 pp.
8. U.S. Environmental Protection Agency, Office of Program Operations.
A Guide to Regulations and Guidance for the Utilization and Disposal
of Municipal Sludge. EPA 430/9-80-015, Washington, D.C., 1980. 48
pp. (Available from National Technical Information Service, Spring-
field, Virginia, PB81 108508)
9. Baker, D.E. and L. Chesnin. Chemical Monitoring of Soils for Envi-
ronmental Quality and Animal and Human Health. Adv. Agron., 27:305-
374, 1975.
10. Petersen, R.G. and L.D. Calvin. Sampling. In: Methods of Soil
Analysis. C.A. Black, ed. American Society of Agronomy, Madison,
Wisconsin, 1965. pp. 54-72.
11. Ellis, R. Sampling and Analysis of Soils, Plants Waste Waters and
Sludge: Suggested Standardization and Methodology. North Central
11-12
-------
Regional Publication 230, Agricultural Experiment Station, Kansas
State University, Manhattan, December 1975. 20 pp.
12. Phung, H. T., L. K. Barker, D.E. Ross and D. Bauer. Land Cultiva-
tion of Industrial Wastes and Municipal Solid Wastes: State-of-
the-Art Study. Vol. 1. EPA 600/2-78-140a, SCS Engineers, Long
Beach, California, October 1978. 220 pp. (Available from National
Technical Information Service, Springfield, Virginia, PB-287 080)
13. Diefendorf, A. F., and D. Ausburn. Ground Water Monitoring Wells.
Public Works, 7:48-50, 1977.
14. Ho, L. V., R. D. Morrison, C. J. Schmidt, and J. R. Marsh. Moni-
toring of Wastewater and Sludge Application Systems. SCS Engi-
neers, Long Beach, California, 1978. 303 pp.
15. Baker, D. E., M. C. Amacher, and W. T. Doty. Monitoring Sewage
Sludges, Soils and Crops for Zinc and Cadmium. In: Land as a
Waste Management Alternative. R.C. Loehr, ed. Ann Arbor Science,
Ann Arbor, Michigan, 1976. pp. 261-281.
16. Standard Methods for the Examination of Water and Wastewater. 14th
Edition. American Public Health Association, Washington, D.C.,
1976. 1193 pp.
18. Environmental Protection Agency National Primary Drinking Water
Regulations. 40 CFR 141.
19. Environmental Protection Agency National Secondary Drinking Water
Regulations. 40 CFR 143.
20. La Conde, K. V., R. J. Lofy, and R. P. Stearns. Municipal Sludge
Agricultural Utilization Practices - An Environmental Assessment,
Volume I. SCS Engineers, Long Beach, California, 1978. 150 pp.
21. U.S. Soil Conservation Service. Drainage of Agricultural Land.
Water Information Center, Port Washington, New York, 1973. 430 pp.
22. Council for Agricultural Science and Technology. Application of
Sewage Sludge to Cropland: Appraisal of Potential Hazards of the
Heavy Metals to Plants and Animals. EPA 430/9-76-013, Ames, Iowa,
November 1976. (Available from National Technical Information Ser-
vice, Springfield, Virginia, PB-264 015)
23. Land Application of Municipal Sewage Sludge for the Production of
Fruits and Vegetables, A Statement of Federal Policy and Guidance,
U.S. Environmental Protection Agency. Washington, D.C., 1981. 21
pp.
11-13
-------
24. U.S. Environmental Protection Agency. Procedures Manual for
Groundwater Monitoring at Solid Waste Disposal Facilities. EPA/
530/SW-611. U.S. Environmental Protection Agency, Cincinnati,
Ohio, 1977.
25. Burge, W. D., and P. B. Marsh. Infections Disease Hazards of Land
Spreading Sewage Wastes. Journal of Environmental Quality, Vol. 7,
No. 1, 1978. pp. 1-9.
26. Kowal, N. E. An Overview of Public Health Effects. Presented at
Workshop on the Utilization of Municipal Wastewater and Sludge on
Land, Denver, Colorado. February 23, 1983. , . .
27. Pahren, H. R., et al. Health Risks Associated with Land Applica-
tion of Municipal Sludge. Journal of Water Pollution Control Fed-
eration. Vol. 51, 1979. pp. 2588-2601.
28» Clark, C. S., et al. Occupational Hazards Associated with Sludge
Handling. Health Risks of Land Application. 6. Bitton, et al.,
eds. Ann Arbor Science, 1980. pp. 215-244.
11-14
-------
APPENDIX'A
CHARACTERISTICS OF SEWAGE SLUDGE
A.I Introduction
Reliable information on sludge composition is needed when designing land
application systems in order to minimize the potential for environmental
or health problems.
A wide range in concentrations for many sludge constituents is found in
the tables of data presented in this Appendix. A variety of factors in-
fluence the composition of sludges, including the proportion of indus-
trial and residential input, the amount of urban runoff, and the combi-
nation of treatment processes used. Thus, sludge composition is varia-
ble from one city to another, and even over time at a specific treatment
plant.
The variability of sludge composition emphasizes the need for a sound
sampling and analysis program. The use of flow weighted sampling proce-
dures is strongly encouraged to obtain representative samples of the
sludge(s) produced. The reliability of sludge composition data is im-
proved by obtaining samples of sludge over a 1 to 2 year period, if pos-
sible. In addition, after a land application program has been initi-
ated, an ongoing sludge sampling and analysis program is needed to ver-
ify that appropriate application rates are used so that these rates can
be adjusted if any significant changes in sludge composition are encoun-
tered.
A.2 Characteristics of Raw Sludges
raw
Table A-l presents typical ranges of
ated by common wastewater treatment processes
in Table A-l should be viewed as general
be used in preliminary planning.
always treated by a stabilization
Stabilization processes include
sludge characteristics gener-
The sludge volumes shown
estimates and, at best, could
Furthermore, sludges are virtually
process prior to land application.
aerobic and anaerobic digestion, com-
posting, drying, storage in a lagoon, etc. Stabilization processes will
reduce the volume of raw ..sludge by 25 to 40 percent because much of the
volatile solids are degraded to carbon dioxide, methane, and other end
products. The actual amounts of stabilized sludge produced in a given
treatment plant are dependent on operational parameters (temperature,
mixing, detention time) and the process used.
A-l
-------
TABLE A-l
QUANTITIES OF RAW SLUDGES PRODUCED BY
VARIOUS TREATMENT PROCESSES (2)
Treatment Processes
Primary settling
Activated sludge
Trickling filters (low
kg Dry Solids/
103m3
108-144
72-108
m3/106m3
Sewage Treatedt
2,500-3,500
15,000-20,000
Percent Water
in Sludge
93-95
98-99
loading)
Trickling filters (high
loading)
Chemical precipitation
(raw sewage)
18-60
72-108
360-540
400-700
1,200-1,500
4,000-6,000
93-95
96-98
> 90-93
* 1 kg/103m3 = 8.33 lb/106 gallons.
t 1 m3/:o6m3 = 1 gal/106 gal.
A.3 Sludge Composition Data
Several studies have been conducted to compile data on the chemical com-
position of municipal sludges produced by POTW's in various states (7)
(12)(29)(33). The data presented in Tables A-2 through A-5 summarize
the composition of sludges from within eight states, primarily in the
midwest. Composition data are tabulated for sludges subjected to aero-
bic digestion, anaerobic digestion and other processes (i.e., lagoon,
primary, trickling filter, etc.). The relationship between volume of
wastewater treated and sludge composition has been evaluated for se-
lected communities in Indiana (Table A-6). Similar data are presented
in Table A-7 for sludge produced by selected communities in Iowa, but
population ranges rather than volumes of wastewater treated are given.
The composition of sludges from 16 large cities in the United States is
shown in Table A-8.
The composition of sludge components does not follow a normal distribu-
tion because of variability in the specific nature of industrial and
other nondomestic inputs into the sewage treatment plant. Several stud-
ies have shown that a log-normal distribution adequately describes
sludge composition data. As a result, the median or gometric mean are
better measures of "typical" concentration than the arithmetic mean.
Wherever possible, median values have been incorporated into Table A-2
through A-7. The following sections will elaborate on the composition
data.
A.3.1 Organic Carbon in Sludge
The organic C content of sludges can range from 6.5 to 48 percent (Table
A-2). The median concentrations of organic C are relatively constant in
most sewage sludges, ranging from 26.8 to 32.5 percent. A variety of
A-2
-------
TABLE A-2
CONCENTRATIONS OF ORGANIC C, TOTAL N, P, AND S
NH4+ AND N03" IN SEWAGE SLUDGE (29)*
Component
Organic C, %
Total N, %
NH4+-N, mg/kg
NO-.--N, mg/kg
*j
Total P, %
Total S, %
Sludge
TypeT
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Number
31
10
60
101
85
38
68
191
67
33
3
103
35
8
3
45
86
38
65
189
19
9
__
28
Range
18-39
27-37
6.5-48
6.5-48
0.5-17.6
0.5-7.6
<0. 1-10.0
<0. 1-17.6
120-67,600
30-11,300
5-12,500
5-67,600
2-4,900
7-830
2-4,900
0.5-14.3
1.1-5.5
<0. 1-3.3
<0.1-14.3
0.8-1.9
0.6-1.1
0.6-1.5
Median
26.8
29.5
32.5
30.4
4.2
4.8
1.8
3.3
1,600
400
80
920
79
180
140
3.0
2.7
1.0
2.3
1.1
0.8
1.1
Mean
27.6
31.7
32.6
31.0
5.0
4.9
1.9
3.9
9,400
950
4,200
6,540
520
300
780
490
3.3
2.9
1.3
2.5
1.2
0.8
1.1
* Concentrations and percent composition are on a dried solids basis.
t "Other" includes lagooned, primary, tertiary, and unspecified sludges.
"All" signifies data for all types of sludges.
A-3
-------
TABLE A-3
CONCENTRATIONS OF K, Na, Ca, Mg, Ba, Fe,
' AND Al IN SEWAGE SlUDGE (29)
Component
K, %
Na, %
Ca, %
Mg, %
Ba, %
Fe, %
Al, %
Type"*"
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
Al 1
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
ATI
Anaerobic
Aerobic
Other
All
Number
86
37
69
192
73
36
67
176
87
37
69
193
87
37
65
189
27
10
23
60
96
38
31
165
73
37
23
133
Range
0.02-2.64
0.08-1.10
0.02-0.87
0.02-2.64
0.01-2.19
0.03-3.07
0.01-0.96
0.01-3.07
1.9-20.0
0.6-13.5
0.12-25.0
0.1-25.0
0.03-1.92
0.03-1.10
0.03-1.97
0.03-1.97
<0. 01-0. 90
<0. 01-0.03
<0. 01-0. 44
<0. 01-0. 90
0.1-15.3
0.1-4.0
<0.1-4.2
<0.1-15.3
0.1-13.5
0.1-2.3
0.1-2.6
0.1-13.5
Median
0.30
0.39
0.17
0.30
0.73
0.77
0.11
0.24
4.9
3.0
3.4
3.9
0.48
0.41
0.43
0.45
0.05
0.02
<0.01
0.02
1.2
1.0
0.1
1.1
0.5
0.4
0.1
0.4
Mean
0.52
0.46
0.20
0.40
0.70
1.11
0.13
0.57
5.8
3.3
4.6
4.9
0.58
0.52
0.50
0.54
0.08
0.02
0.04
0.06
1.6
1.1
0.8
1.3
1.7
0.7
0.3
1.2
* Concentrations on a dry solids basis.
t "Other" includes lagooned, primary, tertiary, and unspecv
fied sludges. "All" signifies data for all types of
sludges.
A-4
-------
TABLE A-4
CONCENTRATIONS OF Pb, Zn, Cu, Ni, Cd, AND Cr
IN SEWAGE SLUDGE (29)
Component
Pb, mg/kg
Zn, mg/kg
Cu, mg/kg
Ni, mg/kg
Cd, mg/kg
Cr, mg/kg
Type1"
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All . -
Number
98
57
34
189
108
58
42
208
108
58
39
205
85
46
34
165
98
57
34
189
94
53
33
180
Range
_ _ _ _ '_
58-19,730
13-15,000
72-12,400
13-19,700
108-27,800
108-14,900
101-15,100
101-27,800
85-10,100
85-2,900
84-10,400
84-10,400
2-3,520
2-1,700
15-2,800
2-3,520
3-3,410
5-2,170
4-520 ,
3-3,410
24-28,850
10-13,600
22-99,000
10-99,000
Median
^uiy/ ^y ;
540
300
620
500
1,890
1,800
1,100
1,740
1,000
970
390
850
85
31
118
82
16
16
14
16
1,350
260
640
890
Mean
1,640
720
1,630
1,360
3,380
2,170
2,140
2,790
1,420
940
1,020
1,210
400
150
360
320
106
135
70
110
2,070
1,270
6,390
2,620
* Concentrations are on a dried solid basis.
t "Other" includes lagooned, primary, tertiary, and unspecified
sludges. "All" signifies data for all types of sludges.
A-5
-------
TABLE A-5
CONCENTRATIONS OF Mn, B, As, Co.. Mo.
IN SEWAGE SLUDGE (29)
AND Hg
Component
Mn, mg/kg
B, mg/kg
As, mg/kg
Co, mg/kg
Mo, mg/kg
Hg, mg/kg
Type*
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Anaerobic
Aerobic
Other
All
Number
81
38
24
143
62
29
18
109
3
7
10
4
9
13
9
3
17
29
35
20
23
78
Range
58-7,100
55-1,120
18-1,840
18-7,100
12-760
17-74
4-700
4-760
10-230
--
6-18
6-230
3-18
,
1-11
1-18
24-30
30-30
5-39
5-39
0.5-10,600
1.0-22
2.0-5,300
0.2-10,600
Median
280
340
118
260
36
33
16
33
116
__
9
10
7.0
4.0
4.0
30
30
30
30
5
5
3
5
Mean
400
420
250
380
97
40
69
77
119
11
43
8.8
4.3
5.3
29
30
27
28
1,100
7
810
733
* Concentrations on a dry solids basis.
* "Other" includes lagooned, primary, tertiary, and unspecified sludges.
"All" signifies data for all types of sludges.
A-6
-------
TABLE A-6
RELATIONSHIP BETWEEN QUANTITY OF WASTEWATER TREATED
AND CHEMICAL COMPOSITION OF SLUDGES IN INDIANA (7)
Component
Total N
NH4-N
Zn
Cd
Cu
Ni
Pb
Cr
PCB
4-10.
(20)
8.94
1.76
1,155
9
610
84
350
440
8.1
Flow
10-20
(12)
6.00
1.11
1,655
22
1,320
180
480
690
4.5
Treated, m3/day
20-40
_(9i_
*t _ .
7.05
1.34
1,800
18
640
80
380
590
6.7
x 103
40-80
(10)
6.81
1.10
2,410
36
790
280
450
1,140
6.7
780
III
5.36
1.08
1,980
62
510
-
-
885
14.5
* Number of treatment plants studies.
t Median concentrations on a dry solids basis.
English conversion factor:
1 m3 = 264.2 gal.
A-7
-------
TABLE A-7
RELATIONSHIPS BETWEEN POPULATION IN SANITARY
DISTRICT AND CHEMICAL COMPOSITION OF SEWAGE SLUDGES
FROM DIFFERENT SIZE CITIES IN IOWA (33)
Component <2
Population of City x 103*
2-10
10-25
25-60
>60
Organic C
Total N
NH/-N
NOjj-N
S
Ca
Mg
Na
K
Fe
39.2
2.55
0.085
0.018
1.12
0.75
5.19
0.58
0.18
0.24
1.72
28.4
3.19
0.057
0.014
1.43
1.34
8.22
0.59
0.54
0.28
1.94
- - v*; -
35.4
2.81
0.080
0.018
0.95
0.98
5.75
0.52
0.17
0.21
1.79
28.0
1.52
0.082
0.011
1.55
1.16
9.25
0.88
0.09
0.19
1.66
28.5
2.28
0.072
0.015
1.22
1.10
8.08
0.73
0.21
0.31
2.13
Ag
As
B
Cd
Co
Cr
Cu
Hg
Mn
Mo
N1
Pb
Se
V
Zn
9
169
100
18
18
38
294
1.2
194
13
25
183
<25
25
1,000
18
163
226
27
25
250
407
2.9
557
13
38
175
<25
25
1,750
- v"'y/">a;
9
175
78
14
21
369
225
0.8
232
13
25
213
<25
28
575
25
163
88
20
18
150
225
1.5
288
13'
38
325
<25
26
1,175
11
171
130
28
24
213
200
0.4
363
13
38
300
<25
38
1,625
* Concentrations and percent composition are on a dry solids
basis.
t Median concentration in sewage sludge from city with a popula-
tion x 10.
A-8
-------
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organic components are present in sludges, including microbial cells and
their decomposition products, chemical compounds present in the wastewa-
ter influent (proteins, polysaccharides, greases, and fats), and com-
pounds synthesized during the wastewater and sludge treatment processes.
The chemical composition of sludge organic C has not been completely de-
fined. Recent studies indicate that phthalate esters, waxes, and fatty
acids are contained in the nonaqueous solvent (e.g., hexane) extractable
fraction of sludges (32). It was also shown that a variety of ami no
acids and two sugars (glucose and xylose) were released from the sludge
solids by acid hydrolysis. Some priority pollutants (e.g., PCB's,'
chlorinated hydrocarbons) can also be present in the organic fraction of
sludges, but their concentrations are typically well under 100 mg/kg.
Most of the organic C found in sludges is insoluble in water, and con-
sists of various proteinaceous, polysaccharide, and lipid-type materials
in various stages of decomposition. The insoluble nature of sludge
organic C means that it is not appreciably removed by dewatering pro-
cesses. The organic C content of sludges placed on sand-drying beds or
composted, however, can be markedly reduced because of the additional
microbial decomposition which occurs during these processes.
A.3.2 Nitrogen Compounds in Sludge
The concentrations of organic nitrogen, NH^ and NOg in sludge are af-
fected by the type of sludge treatment and handling processes used.
Most of the organic N in sludges is associated with the sludge solids.
and thus organic N levels are not appreciably altered by sludge dewater-
ing or drying procedures. In contrast, the inorganic forms of N (NI-L
and NO,) are water soluble, and their concentrations will decrease dra-
maticafly during dewatering steps, e.g., drying-beds, centrifuges,
presses, etc. Either heat or air drying will reduce the NH. because of
ammonia volatilization, but not the NOo level.
Usually, over 90 percent of the inorganic N will be as NH., unless aero-
bic conditions have prevailed during sludge treatment. For most liquid
sludges collected from an anaerobic digester, essentially all the inor-
ganic N will be present as Nt-L, and will constitute from 25 to 50 per-
cent of the total N. The NH^ concentration in the liquid phase of
sludge is relatively constant at a specific treatment plant. Dewatering
of liquid sludges will substantially lower the NH. content, resulting in
a sludge with less than 10 percent of the total N being present as NH*.
Since the inorganic N content of sludges is significantly influenced by
sludge handling procedures, it is essential that nitrogen analysis be
conducted on the actual sludge being considered for land application.
The organic N content of sludges can range from 1 to 10 percent on a dry
weight basis. The organic N compounds found in sludges are primarily
amino acids, indicating the presence of proteinaceous materials (26)
(30). It is likely that the proteins have been partially degraded, and
can be incorporated into stable, humic-type materials. Small amounts of
hexosamines and amides are also found in the organic N fraction of
A-10
-------
sludges. After application to soils, soil microbes will decompose the
organic matter contained in the sludge, resulting in release of NH/1"
which can be assimilated by the vegetation grown.
The amount of inorganic N mineralized in soils is affe.cted by the extent
of sludge processing (e.g., digestion, composting) within the sewage
treatment plant. The amounts of N mineralized in soils will generally
be less for well stabilized sludges. The amounts of N mineralized after
sludge application to soils are discussed in Chapter 6.
A.3.3 Other Components in Sludge
Sewage sludges contain varying concentrations of the other macro- and
micronutrients and other components required for plant growth, as shown
in Tables A-2 through A-5, which include data on sludge levels for P, K,
S, Ca, Mg, Na, Cu, Zn, B, Mo, Fe, Mn, and Co. Several generalizations
are possible concerning the expected concentrations and behavior of
these elements in sludge or sludge soil systems.
Many elements enter the
not readily form either
with particulate materials. Elements in this group include K+, Na,
NH^+, Mo, and Co. As a result, the majority of these elements entering
a treatment plant are discharged in the treated effluent, unless special
advanced treatment processes are used to remove them. Since these ions
are water-soluble, sludge dewatering by centrifuges or presses will
matically lower their concentrations in sludge solids; air or heat
ing will result in increased levels because those ions, which are
volatile.
sewage treatment plant as soluble ions, and do
sparingly soluble compounds or stable complexes
dra-
dry-
non-
Another group of elements readily forms insoluble compounds with con-
stituents which are either initially present in the sewage or produced
during sludge treatment. Included are both inorganic anions (P, S, and
As) and cations (Ca, Mg, Fe, ATI, Mn, Zn, Cu, Ni, Pb, Cd, Cr, and Hg). A
variety of inorganic precipitates can form, including hydroxides,
oxides, carbonates, phosphates, and sulfides; pH, redox potential, and
solution composition will determine which precipitates are formed. The
black color associated with anaerobically digested sludges is attributed
to the formation of insoluble FeS.
Many trace metals, such as Cd, coprecipitate to form insoluble compounds
in sludges. For example, Cd may be trapped within A1(OH)3 or CaCOo sol-
phases during the precipitation process. In addition, metals (Cu,
ids
the
Zn, Cd, etc.) and anions (H^O^", H2As04~) can be adsorbed on the sur-
face of organic matter or precipitates (CaC03, A1(OH)3) in sludges. Be-
cause these chemical reactions remove the ion from solution and concen-
trate it in the solid phase, sludge dewatering has a minimal impact on
their concentration in the final sludge.
A-11
-------
A.3.4 Trace Organics in Sludge
A variety of organic compounds, primarily of industrial origin, have
been receiving greater emphasis as potential pollutants of soils, crops,
and waters following land application of sludges. Initially, chlori-
nated hydrocarbons, pesticides, and polychlorinated biphenyls were the
major organics studied. Data collected in the mid-70's on the concen-
trations of dieldrin (a pesticide) and PCB's were shown in Table A-8 for
selected large cities in the United States. Dieldrin concentrations
were generally less than 0.3 mg/kg while PCB's ranged from under 0.01 to
23 mg/kg. A survey of sludges produced by treatment plants in Indiana
indicated that the median PCB concentrations ranged from 4.5 to 14.5
mg/kg (Table A-6). The levels of PCB's in sludges should decrease in
the future because these compounds are no longer being manufactured.
More recent research has concentrated on characterizing the myriad of
trace organic compounds that are entering municipal sewage treatment
plants (4). Analysis of sludges from 25 cities has indicated that sev-
eral phthalate esters (i.e., diethyl, dibutyl) are present in 13 to 25
percent of sludges at concentrations above 50 mg/kg (Table A-9). Tolu-
ene, phenol, and naphthalene were also found in 11 to 25 percent of the
sludges at higher than 50 mg/kg levels. Chlorinated methanes, ethanes,
and benzenes were found in 3 to 36 percent of the sludges at concentra-
tions above 1 mg/kg, but they were found in relatively .few sludges at
above 50 mg/kg. Trace organics have also been surveyed in 238 sludges
generated by treatment plants in Michigan (Table A-10). The compounds
detected in these sludges included acrylonitrile, chlorinated hydrocar-
bons, chlorinated benzenes, chlorinated phenols, styrene, and hydroqui-
none. Compounds found in over 25 percent of the sludges include 1,2-
and 1,3-dichloropropane, 1,3-dichloropropene, tetrachloroethylene, 2,4,-
dinitrophenol, hydroquinone, pentachlorophenol, phenol, and 2,4,6,-tri-
chlorophenol. Of these compounds, median concentrations were below 5
mg/kg, except for tetrachloroethylene (29 mg/kg). Styrene was found in
6 of 219 sludges, ranging in concentration from 99 to 5,858 mg/kg.
Chlorobenzene and chlorotoluene were present in 6 sludges at levels
ranging from 60 to 846 mg/kg. These data suggest that most trace organ-
ics will be present in most sludges at concentrations of less than 10
mg/kg. However, industrial in-put of a specific organic compounds can
dramatically increase sludge concentrations. Both of these studies have
shown that there is a weak relationship between the proportion of total
flow contributed by industries and the concentration of trace organics
in sludges (4-)(25).
A.4 Effect of Sludge Treatment and Chemical Amendments on Sludge
Characteristics
The sludge treatment processes used can have a significant affect on the
chemical composition of sludge. Sludge stabilization processes such as
aerobic and anaerobic digestion result in decomposition of sludge or-
ganic matter and the release of carbon dioxide, ammonium, hydrogen sul-
fide, and phosphate. Thus, the organic C, N, S, and P content in
A-12
-------
TABLE A-9
ORGANIC COMPOUNDS DETECTED.IN SLUDGES (4)'
Percent Occurrence at
Concentrations
Compound
Methane, dichloro-
Methane, trichloro-
Ethane, 1,1,1-trichloro-
Ethane, trichloro-
Ethane, tetrachloro-
Benzene, 1,4^-dichloro
Ethylbenzene
Toluene
Phenol , . ; .
Naphthalene
Phenanthrene
Phthalate di ethyl
Phthalate, di-n-butyl
Phthalate, bis (2-ethyl hexyl )
Phthalate, butylbenzyl
All others
>1- mg/kg
': .41 .
3
5
26
: 27
36
33
59
63
65
60
43
63
75
50 ,
<50
>10 mg/kg
12
0
3 .
9
8
18
3
35
25
33
20
23
25
63
35
<25
Indicated
>50 mg/kg
3
0
0
3
3
5
; 0
11
13
15
8
13
13
25
18
<15
* Survey of 25 cities located throughout the United States.
Plant treated from 13,200 md/day to 1S170,000 m3/day and
percentage of industrial flow varied from 0 to 60 percent.
t Dry solids basis.
A-13,
-------
TABLE A-10
CHARACTERIZATION OF ORGANIC COMPOUNDS IN
238 SLUDGES COLLECTED FROM TREATMENT PLANTS IN MICHIGAN (25)
Compound
Acrylonltrile
Chlorobenzene
p-chlorotoluene
o-di chl orobenzene
m-d1 chlorobenzene
p-dichl orobenzene
1 , 2-di chl oropropane
1,3-dlchloropropane
1,3-di chl oropropane
Ethyl benzene
Hexachloro-1,3-
butadiene
Hexachloroethane
Pentachloroethane
Styrere
Tetrachl oroethyl ene
1, 2, 3~tr1 chl orobenzene
1, 2, 4-trichl orobenzene
1 ,3, 5-tri chl orobenzene
I,2,3~tr1chl oropropane
1, 2, 3-trichl oropropane
o-chlorophenol
m-chlorophenol
p-chlorophenol
o-cresol
2, 4-di chl orop henol
2, 4-d1raethyl phenol
4,6-dinitro-o-cresol
2,4-din1trophenol
Hydroqui none
Pentachlorophenol
Phenol
2,4,6-tn'cnlorophenol
Detection Limit
4 (25/155)
60 (3/158)
59 (6/158)
6 (15/215)
5 (44/216)
10 (18/216)
0.08 (91/157)
0.5 (40/158)
0.1 (119/157)
0.08 (14/220)
3 (1/217)
0.05 (40/217)
0.4 (5/199)
90 (6/219)
10 (108/128)
1 (7/216)
3 (17/217)
50 (0/217)
4 (2/141)
3 (21/137)
0.03 (20/231)
0.03 (16/231)
0.03 (19/231)
0.03 (16/231)
0.03 (17/230)
0.03 (41/231)
0.06 (20/229)
0.18 (66/228)
0.07 (61/229)
0.03 (155/223)
0.03 (178/229)
0.06 (66/223)
Range Mean1"
4-82
60-846
93-324
6-809
6-1,651
10-633
0.09-66
0.6-309
0.1-1,232
1.2-66
_
0.05-16.5
0.4-9.2
99-5,848
1-1,218
1-152
3-51
-
9-19
3-167
0.1-93
0.1-90
0.2-183
0.2-203
D. 09-87
0.2-187
0.3-500
0.1-223
0.2-8,495
0.05-288
0.2-1,333
16±19
3371441
153+87
89±209
119+327
77±151
1.91±7.36
18+51
24+116
25±22
4
0.7.+2.6
2.7±3.7
1,338±2,249
68±132
25±56
14+12
-
14±7
23+47
13±23
9+24
18±30
25+52
25+54
6.5+14.9
12.7+41
24±81
8+29
81+685
9+29
42+178
Median
7
106
.121
16
22
23
0.66
3.2
3.9
20
-
0.2
1.3
405
29
1
13
-
14
6
0.9
3.6
2.0
4.8
2.2
2.3
5.0
2.6
5.0
2.0
4.3
* Number in parenthesis is the number of sites having concentrations less than
detection limit/total number of sites analyzed.
t Mean ± standard deviations.
I Concentrations on a dry solids basis.
A-14
-------
stabilized sludges will be lower than the raw sludge entering the sta-
bilization unit. Composting of sludges results in further decreases in
the organic constituents found in sludges. In addition, composting may
involve mixing sludge with a bulking agent (e.g., wood chips) to facili-
tate aeration and rapid stabilization of the sludge. In some cases, the
majority of the bulking agent is removed from the finished compost by
screening; but even in these cases a portion of the bulking agent re-
mains in the compost resulting in dilution of sludge components (e.g.,
nutrients, metals). The extensive biological activity occurring during
composting results in further decreases in the organic N, C, and S con-
tent of the sludge. In general, the organic N content of sludges de-
=creases in the following order: raw, primary or wasted activated, di-
gested, and composted.
Wastewater and sludge treatment processes often involve the addition of
ferric chloride, alum, lime, or polymers. Obviously, the concentration
of the elements added will increase their concentration in the resultant
sludge. In addition, the compound added can have other indirect effects
on sludge composition. For example, alum precipitates as aluminum hy-
droxides, which can subsequently adsorb P and coprecipatate with trace
metals such as Cd. Lime (calcium oxide or hydroxide) used as a sludge
stabilization agent will ultimately precipitate in sludges as calcium
carbonate which can also retain P and metals. Lime addition may also
result in alkaline hydrolysis of organic N compounds and cause losses of
ammonia through volatilization.
A.5 Variability of Sludge Composition
The data discussed previously have emphasized the variability that can
be encountered in the composition of sludges generated in different
municipalities. The composition of sludges can also vary with time at a
given treatment plant. Several studies have been conducted to assess
the variable nature of sludge characteristics (6)(15)(31). Representa-
tive data on the variability of total N, P, and K (Figure A-l) and Zn,
Cd, and Cu (Figure-A-2) in sludges are shown for samples obtained from
two treatment plants in Pennsylvania during a two year period. It is
apparent that significant variations in sludge composition can occur
both for constituents that are primarily soluble (K) or insoluble (P and
metals), but this may differ between POTW's. The volume and frequency
of industrial metal in-puts are probably responsible for the variations
found in the Zn, Cd, and Cu concentrations. Also, operational parame-
ters within the treatment plant can alter the solids content and other
sludge characteristics. Not all cities generate sludges as variable as
those depicted in Figures A-l and A-2.
The data shown on the variability of sludge composition emphasize the
need for a sound sampling program. The use of flow-weighted sampling
procedures is strongly encouraged to obtain representative samples of
sludge produced at a specific treatment plant. An on-going sludge sam-
pling and analysis program is essential to assure the integrity of a
land application system. Only through proper monitoring can significant
A-15
-------
5.0-r
H-
r
yj
>-<
UJ
3
>
Di
Q
J-
Z
UJ
u
o:
ILJ
CL
z
o
l-<
H
<
CC
H
z
LU
U
0
U
3.0 -
2.0 -
1.0 -
TOTAL N
TOTAL P
TOTAL K
23
23
CITY ^0.
23
Figure A-l. Variability of N, P, and K-in sewage sludge (6)
_2 COPPER X 10
-2
o 18°-
^ 160 -
(3
s. 140-
Z 120-
o
CONCENTRATI
>-*
M f- O\ CO O
JO O O O O
1 1 1 1 1
ZINC X 10
T
f
f
2 3
V-MUI"! iUI'l /S 1 U
4
-2
I
I
* fl ««d
23 2.3
CITY NO.
Figure A-2,
Variability of Zn, Cd, and Cu in sewagesludge
from two POTW's in Pennsylvania over a 2-year
period (6).
A-16
-------
changes in the concentration of limiting nutrients or metals be de-
tected, so that sludge application rates can be altered accordingly.
A.6 Pathogens Potentially Associated with Sludge
A.6.1 General
Pathogenic microorganisms such as bacteria, viruses, protozoa, and para-
sitic worms are almost always present in raw sewage. The number and
types of organisms present in raw sewage, however, varies from community
to community, depending upon urbanization, population density, sanitary
habits, season of the year, rates of disease in the contributing commun-
ity (13). Table A-ll lists disease-causing bacteria and parasites which
have been identified in raw sewage and sludge, and Table A-12 lists
human enteric viruses which have been isolated from sewage (11). Sludge
stabilization processes destroy the great majority of the pathogens
listed in Tables A-l and A-2, as discussed in Section A6.6.
A.6.2 Bacteria
Enteric bacilli, which naturally inhabit the gastrointestinal tract of
man, have been classified into three general categories: pseudomonas,
salmonella, and -shigella species. None of the enteric bacilli form
spores. Spores are resistant bodie"sproduced within the cells of a
large number of bacterial species which enables them to withstand unfav-
orable environmental conditions such as heat, cold, desiccation, and
chemicals (12). Since enteric bacilli are non-spore formers, their sur-
vival outside their normal environment is usually measured in days or
months, compared to years for spore-forming bacteria. The most common
bacterial pathogens associated with sewage are Salmonella. Shi gel!a,
Vibrio, and Campylobacter (Table A-ll). More than 110 different virus
types may be present in raw sewage (Table A-12). The list of pathogenic
human enteric viruses has continued to grow during the last decade.
Rotaviruses are now recognized as a major cause of child gastroenteri-
tis, and also cause diarrhea in adults (11). Other major pathogenic en-
teric viruses are the Polioviruses, Coxsackievi ruses, Echovi ruses, and
the Hepatitis virus. These viruses are shed from the body through the
feces, and fecal-oral spread is probably the most common method of
transmission. For man, the enteric virus of greatest potential concern
appears to be Hepatitis A.
A.6.3 Parasites
Parasites include protozoans, nematodes, and helminths (Table A-ll).
Intestinal protozoans are transmitted by a cyst, the nonactive and envi-
ronmentally insensitive form of the organism. Their life cycle requires
that a cyst be ingested by the host. The cyst is transformed into an
active feeding organism (trophozoite) in the intestines, where it ma-
tures and reproduces, releasing cysts in the feces (25).
A-17
-------
TABLE A-ll
BACTERIA AND PARASITES IN SEWAGE AND SLUDGE
Group
Bacteria
Protozoa
Helminths
Pathogen
Salmonella (1700 types)
Shi gel la
Enteropathogenic Escherichia
coli
Yersinia enterocolitica
Campy!obacter jejuni
Vibrio cholerae
Leptospira
Entamoeba histolytica
Giardia lamblia
Balantidium coli
Ascaris lumbricoides
(Roundworm)
Ancyclostoma duodenale
(Hookworm)
Necator americanus
(Hookworm)
Taenia saginata
(Tapeworm)
Disease Caused
Typhoid, paratyphoid,
salmonellosis
Bacillary dysentery
Gastroenteritis
Gastroenteritis
Gastroenteritis
Cholera
Weil's disease
Amebic dysentery, liver
abcess, colonid ulceration
Diarrhea, malabsorption
Mild diarrhea, colonic
ulceration
Ascariasis
Anemia
Anemia
Taeniasis
A-18
-------
TABLE A-12
HUMAN ENTERIC VIRUSES IN SEWAGE
Virus
Enterovi ruses:
Poliovirus
Echovirus
Coxsackievirus
Coxsackievirus
Number
of
Types
3
31
23
6
Diseases Caused
Meningitis, paralysis, fever
Meningitis, diarrhea, rash, fever,
respiratory disease
Meningitis, herpangina, fever,
respiratory disease
Myocraditis, congehtial heart
New enteroviruses
(Types 68-71)
Hepatitis Type A
(enterovirus 72?)
Norwalk virus
Calicivirus
Astrovirus
Reovirus
Rotavirus
Adenovirus
anomalies, pleurodynia, respiratory
disease, fever, rash, meningitis
Meningitis, encephalitis, acute
hemorrhagic conjunctivitis, fever,
respiratory disease
Infectious hepatitis
1 Diarrhea, vomiting, fever
1 Gastroenteritis
1 Gastroenteritis
3 Not clearly established
2 Diarrhea, vomiting
37 Respiratory disease, eye infections
A-19
-------
Of the common protozoa which may be found in sewage, only three species
are of major significance for transmission of disease to human: Enta-
moeba histolytica, Giarda Iambi a, and Balantidium coli. All of these
organisms are known to cause mild to severe diarrhea (11).
Although helminth infections are still prevalent in the U.S. population,
the occurrence of disease due to three agents in the United States has
been extremely low during the last few decades. The presence and levels
in wastewater of helminth eggs depend on the levels of disease in the
population (11). Helminths (worms) include the subgroups, nematodes and
trematodes. The intestinal nematode, Ascaris lumbricoides, is fre-
quently mentioned as a potential problem to human health.PaTasitic ova
are generally quite resistant to disinfectants and adverse environmental
conditions (12). The ova of Ascaris have been shown to survive sewage
treatment. Since a portion of animal waste reaches municipal sludges,
parasites of animal origin are also of concern. The nemathodes, Toxa-
cara can is arid T. cati, found in the dog and cat population, have a life
cycle which is nearly identical to that of Ascaris in man (28).
A.6.4 Fungi
Fungi are secondary pathogens in sludge. A large number have been found
growing in sludge undergoing composting. The pathogenic fungi are of
most concern when the spores are inhaled by people who are already
stressed by a disease such as diabetes or by immunpsuppressive drugs
(20).
Fungi spores, especially those of Aspergillus fumigatus, are ubiquitous
in the environment, and have been found in pastures, haystacks, manure
piles, and the basements of most homes. This fungus grows exceptionally
well at human body temperature, and causes asthmatic symptoms in
allergy-prone individuals.
Although there is a greater potential of transacting pathogenic fungi
and actinomycetes during composting, there is also a possibility of in-
haling such spores while applying sludge to land. However, there have
been no reports involving such cases at sludge-to-land sites (3).
A7.0 Reduction of Pathogens by Sewage and Sludge Treatment Processes
Sewage and sludge treatment processes significantly reduce the number of
pathogens originally present in the raw sewage. Table A-13 shows per-
cent removal of pathogens by various sewage treatment processes. It is
clear, however, that some pathogens may survive sludge stabilization
processes. Table A-14 lists reported concentrations of enteric viruses
in sludge receiving various types of treatment. As shown in the table,
sludge which has been stabilized (e.g., digested, lagooned) has very low
concentrations of viruses compared to raw sludge.
Table A-15 shows
sludge. As shown
reported parasite concentration in raw and treated
in the table, parasite eggs ^iave high survival rates
A-20
-------
TABLE A-13
PERCENT REMOVAL OF PATHOGENS BY VARIOUS
SEWAGE TREATMENT PROCESSES (9)
Treatment
Primary !
Sedimentation
Trickling
Filter*
Activated
Sludge*
Oxidation
Ditch*
Waste Stabilization
Ponds (three cells
with >25 days'
retention)
Enteric
Viruses
0-30
90-95
90-99
90-99
99.99-100
Bacteria
50-90
90-95
90-99
90-99
99.99-100
Protozoan
Cysts
10-50
50-90
50
50
100
Helminth
Eggs
30-90
50-95
50-99
50-99
100
With sedimentation, sludge digestion, and sludge drying.
A-21
-------
TABLE A-14
REPORTED CONCENTRATION OF ENTERIC
VIRUSES IN SLUDGES (11)
Type of Sludge
Raw
Mixed liquor
suspended solids
Aerobically digested
Lagooned sludge
applied to land
Raw
Digested
Lagooned
Raw
Anaerobi c-mesop hi lie
Raw
Anaerobic-mesophilic
digestion
Aerobic-therraophilic
digestion
Anaerobic high rate
digestion
Anaeroblcally
digested lagoon
Anaerobic digestion
Raw
Anaerobic-mesophil ic
Aerobic-thermophilic
Anaerobic-mesophil ic
Aerobic digestion
Concentration
5-145 pfu/ral
5 TCID50/g
1.7 to 5.2 TCID
0.02 to 4.6
50
6.9 to 215 pfu/g
0.2 to 17 pfu/g
1.2 pfu/g
17.9 TCID50/100 ml
0.85 TCI050/100 ml
40 to 1,419 pfu/g
6 to 210 pfu/g
10 to 65 pfu/g
1.1 to 17 pfu/g
1.2 pfu/g
5.0-6.7 pfu/g
141-1,060 pfu/100 ml
4-100 pfu/100 ml
0-14 pfu/100 ml
0.8 pfu/ml
14 to 260 TCID50/g
Location
Cincinnati
Florida
England
United States
A-22
-------
TABLE A-15
PARASITE CONCENTRATION IN PRIMARY AND SECONDARY
SLUDGE AS COMPARED TO TREATED SLUDGE (25)
Number of Viable and Nonviable
Eggs/Kg Dry Height of Sample
Parasite
Ascaris spp.
(human and pig
roundworm)
Tri churis
trichiura (human
whipworm)
Trichuris vulpis
(dog whipworm)
Toxocara spp.
(dog and cat
roundworm)
Type
Primary
Treated
Primary
Treated
Primary
Treated
Primary
Treated
of Sludge*
and Secondary
and Secondary
and Secondary
and Secondary
Average
9,700
9,600
800
2,600
600
700
1,200
700
Percent Viable Eggs
45
69
50
48
90
64
88
52
* Primary and secondary sludges include sludges from primary clarification,
Imhoff digestion, activated sludge, contact stabilisation, and extended
aeration. Treated sludges include sludges from mesophilic aerobic and an-
aerobic digestion, vacuum filtration, centrifugation, lagoons, and drying
beds.
A-23
-------
through common sludge stabilization processes. The level of pathogen
reduction achieved during sludge treatment varies with the process used
and numerous other variables (e.g., time, temperature, pH, etc.). De-
tailed studies of the mechanisms of virus inactivation during sludge
treatment have shown ammonia and detergents play a significant role.
Drying and loss of moisture from sludge can result in significant inac-
tivation1 of viruses. There is a 4 to 5 logiQ decrease in virus numbers
when the final sludge solid is above 90%. Dewatering causes the release
of viral RNA and inactivation appears to be due to the dewatering pro-
cess itself (34).
In sludge composting, sludge is mixed with other organic materials such
wood chips or leaves, and is allowed to decompose for a period ranging
from 3 to 4 v/eeks. Aerobic conditions are maintained either by pumping
air into the compost pile, or by regularly turning the pile. Compost-
ing, being a thermophilic process with temperatures ranging from 60° to
70°C under ideal conditions, generally results in inactivation of patho-
genic microorganisms. Protozoan cysts, helminth eggs, and pathogenic
bacteria are effectively inactivated during this process. Experiments
with model viruses (bacterial virus f2) have revealed that a properly
operated Nindrow compost system may result in total virus inactivation
in approximately 50 days. Enteric virus monitoring of a windrow compost
system has revealed their presence during the windrow phase, but none
after the curing period (1).
Recent studies have also been conducted on the concentration of helminth
in domestic sludges in the United States. Significant numbers of these
parasites may survive both aerobic and anaerobic sludge treatment. As
in the case of viruses, sludge drying (i.e., loss of moisture) has a
great influence on the inactivation of parasites in sludges (30).
Radiation processing of sludge by exposure to high-energy electrons pro-
duced by an electron accelerator or radiation sources appears to be
highly effective against pathogenic microorganisms and helminths (8).
A.8 Survival of Pathogens Applied to Land
Survival of pathogens contained in sludge after the sludge is applied to
the land is obviously an important consideration in deciding how long a
period of time must be allowed after the last sludge application before
permitting access to the people and/or animals, and the harvesting of
crops intended for human consumption. In addition, pathogen survival
may affect the possible contamination of surface or ground water. Fac-
tors known to influence bacterial and viral survival in the soil are
listed in Table A-16.
Temperature is an important factor in the survival of bacteria and
viruses. Their survival is greatly prolonged at low temperatures; below
4°C, they can survive for months or even years. At higher temperatures
inactivation or die-off is fairly rapid. In the case of bacteria, and
probably viruses, the die-off rate is approximately doubled with each
10°C rise in temperature between 5° and 30°C (24).
A-24
-------
TABLE A-16
FACTORS THAT INFLUENCE THE SURVIVAL OF BACTERIA
AND VIRUSES IN SOIL (11)
Factor
Temperature
PH
Cations
Bacteria
Viruses
Longer survival at low temperature;
longer survival in winter than in summer
Shorter survival time in
acid soils (pH 3-5) than
in alkaline soils
Desiccation
and soil
moisture
Sunlight
Antagonism from
soil microflora
Organic matter
Greater survival time in
moist soils and during
times of high rainfall.
Survival time is less
in sandy soils with lower
waterholding capacity.
May indirectly affect
virus survival by con-
trolling their adsorp-
tion to soils
May also indirectly in-
fluence virus survival
by increasing their ad-
sorption to soil (vi-
ruses appear to survive
better in the sorbed
state)
One of the most proven
detrimental factors.
Increased virus reduc-
tion in drying soils.
May be detrimental at the soil surface
Increased survival time
sterile soil
Increased survival and
possible regrowth whe'n
sufficient amounts of
organic matter are
present
No clear trend with
regard to the effect of
soil microflora on
viruses
Unknown
A-25
-------
The survival of bacteria on plants, particularly crops, is especially
important, since these may be eaten raw by animals or humans, may conta-
minate hands of workers touching them, or may contaminate equipment con-
tacting them. Such ingestion or contact would probably not result in an
infective dose of a bacterial pathogen; but if contaminated crops are
brought into the kitchen in an unprocessed state, they could result in
the regrowth of pathogenic bacteria (e.g., Salmonella) in a food mate-
rial affording suitable moisture, nutrients, and temperature.
Pathogens do not penetrate into vegetables or fruits unless their skin
is broken; and many of the same factors affect bacterial survival on
plants as those in soil, particularly sunlight and desiccation. The
survival times of bacteria on subsurface crops (e.g., potatoes and
beets) would be similar to those in soil (2).
The survival of enteric bacteria on crops has been extensively studied,
and reviewed. Reported survival times for common bacteria pathogens
range from less than 1 day to 6 weeks.
Virus survival on exposed plant surfaces would be expected to be shorter
than in soil because of the exposure to deleterious environmental ef-
fects, especially sunlight, high temperature, and drying. Reported sur-
vival time of viruses on crops is similar to those of bacteria, and
likewise appears to support a 1-month waiting period after last wastewa-
ter application before harvest. Because of their exposure to the air,
desiccation, and sunlight, protozoan cysts and helminth eggs deposited
on plant surfaces would also be expected to die off rapidly.
Land application of digested sludges has shown little impact of bacter-
ial contamination of ground water, provided that the ground water table
is not too high and the soil is well drained (17)(36).
A.9 References
1. Bitton, 6. Introduction to Environmental Virology. Wiley, New
York, 1980.
2. Bryan, !:. L. Disease Transmitted by Foods Contaminated by Wastewa-
ter. J., Food Protect., 40:45-56, 1977.
3. Burge, W. D., and P. B. Marsh. Infectious Disease Hazards of Land-
spreading Sewage Wastes. J. Environ. Qual., 7:1-9, 1978.
4. Cohen, J. M., L. Rossman, and S. A. Hannah. National Survey of
Municipal Wastewaters for Toxic Chemicals. Presented at the 8th
U.S./Japan Conference, Cincinnati, on Sewage Treatment Technology,
October 1981.
5. Criteria for Classification of Solid Waste Disposal Facilities and
Practices. Federal Register, 44:53438-53468, September 13, 1979.
A-26
-------
7.
Doty,, W. T., D. E. Baker, and R. F. Shipp. Chemical Monitoring of
Sewage Sludge in Pennsylvania. J. Environ. Qual., 6:421-426, 1977.
Echelberger, W. F., Jr., J. M. Jeter, F. P. Girardi, P. M. Ramey,
G. Galen, D. Skole, E. Rogers, J. C. Randolph, and J. Zogaski.
Municipal and Industrial Wastewater Sludge Inventory in Indiana.
Chemical Characterization of Municipal Wastewater Sludge in Indi-
ana, Part 1. School of Public and Environmental Affairs, Indiana
University, Bloomington, 1979.
8.
Epp, C.,
Sludge.
Abt. I:
and H. Metz. Virological Analyses of Irradiated Sewage
Zentralbl. Bakteriol. Parasitenk. Infektionskr. Hyg.
Orig. Reihe B, 171:86-95, 1980.
9. Feachem, R. G., D. J. Bradley, H. Garelick, and D. D. Mara. Appro-
priate Technology for Water Supply and Sanitation: Health Aspects
of Excreta and Si 11 age Management: A State of the Art Review.
World Bank, Washington, D.C., 1980.
10. Furr, A. K., A. W. Lawrence, S. S. C. long, M. C. Grandolfo, R. A.
Hofstader, C. A. Bache, W. H. Gutenmann, and D. J. Lisk. Multi-
element and Chlorinated Hydrocarbon Analysis of Municipal Sewage
Sludges of American Cities. Environ. Sci. Techno!., 10:683-687*
1976.
11. Gerba, C. P. Pathogens Presented at a Workshop on Utilization of
Municipal Wastewater and Sludge on Land, Denver, February 1983.
12. Gleason, T. L. Ill, F. D, Kover, and C. A. Sorber. Health Effects:
Land Application of Municipal Wastewater and Sludge. In: Proceed-
ings of the National Conference on Disposal of Residues on Land,
St. Louis, September 1976. pp. 203-210.
13. Hoadley, A. W., and S. M. Goyal (1976) Public Health Implications
of the Application of Wastewaters to Land. In: Land Treatment and
Disposal of Municipal and Industrial Wastewater. R. L. Sanks and
T. Asano, eds. Ann Arbor Science, Ann Arbor, Michigan, 1976. pp.
101-132.
14. Kalinske, A. A. Municipal Wastewater Treatment Plant Sludge and
Liquid Sidestreams. EPA-43Q/9-76-007, Camp, Dresser and McKee,
Boston, June 1976. 123 pp.
15. Kelling, K. A., A. E. Peterson, L. M. Walsh, J.
Keeney. A Field Study of the Agricultural Use
Effect on Crop Yield and Uptake of N and P.
339-345, 1977. (Available from the National
Service, Springfield, Virginia, PB-255 769)
A. Ryan, and D. R.
of Sewage Sludge:
J. Environ. Qua!., 6:
Technical Information
16. Kowal, N. E. Health Effects of Land Treatment: Microbiological.
EPA-600/1-82-007, Health Effects Research Laboratory, Cincinnati,
A- 27
-------
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
May 1982. (Available from the National Technical Information Ser-
vice, Springfield, Virginia, PB82 253949)
Liu, D. The Effect of Sewage Sludge Land Disposal on the Microbio-
logical Quality of Groundwater. Water Res., 16:957-961, 1982.
U.S. EPA. Process Design Manual for Land Treatment of Municipal
Wastewater. EPA-625/1-77/008, October 1977. 596 pp. (Available
from the National Technical Information Service, Springfield, Vir-
ginia, PB-299 655)
Metcalf and Eddy. Wastewater Engineering:
and Disposal. McGraw-Hill, New York.
Collection, Treatment,
Moore, B. E., B. P. Sagik, and C. A. Sorber. An Assessment of Po-
tential Health Risks Associated with Land Disposal of Residential
Sludges. Presented at the Third National Conference on Sludge Man-
agement and Utilization, Miami, 1976.
Page, A. L. Fate and Effects of Trace Elements in Sewage Sludge
When Applied to Agricultural Lands; a Literature Review Study.
EPA-670/2-74-005, University of California, Riverside, January
1974. 107 pp.
U.S. EPA. Wastewater Treatment and Reuse by Land Application.
Vol. II. EPA 660-/2-73-006, August 1973. (Available from the
National Technical Information Service, Springfield, Virginia, PB
225 941)
Process Design Manual for Sludge Treatment and Disposal. EPA-625/
1-79-011, Center for Environmental Research Information, Cincin-
nati, September 1979. 1135 pp. (Available from the National Tech-
nical Information Service, Springfield, Virginia, PB80 200546)
Reddy, K. R., R. Khaleel, and M. R. Overcash.
port of Microbial Pathogens and Indicator
Treated with Organic Wastes. J. Environ. Qual
Behavior and Trans-
Organisms in Soils
, 10:255-266, 1981.
Reimers., R. S., M. D. Little, A. J. Englande, D. B. Leftwich, D. D.
Bowman, and R. F. Wilkson. Parasites in Southern Sludges and Dis-
infection by Standard Sludge Treatment. EPA-600/2-81-166. Tulane
University School of Public Health, New Orleans, September 1981.
203 pp. (Available from the National Technical Information Ser-
vice, Springfield, Virginia, PB82 102344)
Ryan, J. A., D. R. Keeney, and L. M. Walsh. Nitrogen transforma-
tions and availability of an anerobically digested sewage sludge in
soil. J. Environ. Qual., 2:489-492, 1973.
Salle, A. J. Fundamental Principles of Bacteriology. McGraw-Hill,
New York, 1973.
A-28
-------
28. U.S. EPA. Sludge Treatment and Disposal. Volume 2: Sludge Treat-
ment. EPA-625/4-78/012-Vol-2, Cincinnati, Environmental Research
Center, October 1978. 160 pp. (Available from the National Tech-
nical Information Service, Springfield, Virginia, PB-299 594)
29. Sommers, L. E. Chemical Composition of Sewage Sludges and Analysis
of Their Potential as Fertilizers. J. Environ. Qual., 6:225-239,
1977.
30. Sommers, L. E., D. W. Nelson, J. E. Yahner, and J. V. Mannering.
Chemical Composition of Sewage Sludge from Selected Indiana Cities.
Proc. Indiana Acad. Sci., 82:424-432, 1972.
31. Sommers, L. E., D. W. Nelson, and K. J. Yost. Variable Nature of
the Chemical Composition of Sewage Sludge. J. Environ. Qual., 5:
303-306, 1976.
32. Strachan, S. D., D. W. Nelson, and L. E. Sommers. Sewage Sludge
Components Extractable with Nonaqueous Solvents. J. Environ.
Qua!., 12:69-74, 1983.
33. Tabatabai, M. A., and W. T. Frankenberger, Jr. 1979. Chemical
Composition of Sewage Sludges in Iowa. Res. Bull. No. 586, Agri-
cultural and Home Economics Experiment Station, Iowa State Univer-
sity, Ames, 1979.
34. Ward, R. L., and C. S. Ashley. Inactivation of Enteric Viruses in
Wastewater Sludge Through Dewatering by Evaporation. Appl. Envi-
ron. Microbiol. 34:564-570, 1977.
35. Zabik, M. J., L. W. Jacobs, and J. H. Phillips. Concentrations of
Selected Hazardous Chemicals in Michigan Sewage Sludges and Their
Impact on Land Application. Unpublished data. Michigan State Uni-
versity, East Lansing, 1981.
36. Zenz, D. R., J. R. Peterson, D. L. Brooman, and C. Lue-Hing. Envi-
ronmental Impacts of Land Application of Sludge. J. Water Pollut.
Control Fed., 48:2332-2342, 1976.
A-29
-------
-------
APPENDIX B
EFFECTS OF SLUDGE APPLICATIONS TO LAND ON SOILS AND PLANTS
B.I General Properties of Soils
Soil is a complex mixture of inorganic and organic constituents. The
inorganic fraction may consist partially of clay minerals, other sili-
cate minerals, oxides, and carbonates. The organic fraction usually
contains both humic and nonhumic substances. The proportions and prop-
erties of inorganic and organic components in soils are a function of
time, climate, topography, vegetation, and parent material. In a well-
aggregated soil, soil particles and pore space usually constitute about
50 percent each of the volume. Optimum conditions for plant growth
exist when the soil pore space is about half occupied by air and half by
water. With respect to the solid phase, the texture of a soil is de-
fined by the relative proportion of particles found in the sand (>0.05
mm), silt (0.002 to 0.05 mm), and clay (<0.002 mm) size fractions.
Through use of a texture triangle (Figure B-l), a soil horizon contain-
ing a certain percentage of sand, silt, and clay is assigned a name,
such as sandy loam, silt loam, silty clay loam, etc.
Clay minerals, one of the more important inorganic fractions of a soil,
are composed of layered sheets of tetrahedrally and/or octahedrally co-
ordinated cations. The sheets of Si tetrahedra and Al octahedra are
present in a 1:1 or 2:1 configuration. Kaolinite is a typical 1:1 clay
montmorillonite and vermiculite are typical 2:1 clays.
aluminum or iron (+3) is substituted for tetravalent sil-
divalent magnesium or iron (+2) for trivalent aluminum
mineral while
When trivalent
icon (+4) and
(+3), a permanent net negative charge results on the surface of the clay
mineral. This negative charge is satisfied by surface retention of a
cation such as H+, K+, Na+, Ca , Mg , Al , etc. The magnitude of the
negative charge is measured by determining the cation exchange capacity
(CEC), commonly expressed in meq/100 g. The CEC arising from isomor-
phous substitution is not pH-dependent. However, clay minerals possess
some pH-dependent CEC, arising from the dissociation of hydroxyl groups
(-OH) present at the edges of broken clay crystals. The ability of clay
minerals to attract and retain cations is a very important property in
soils.
Soil CEC will be discussed later in detail. In addition to CEC, addi-
tional properties of clays include a high surface area, the capacity to
sorb metals and some organic compounds, and the ability to swell or
shrink depending on Water content.
Other silicate minerals are less important than the clay minerals, pri-
marily because of their minimal CEC and low surface area. Included in
this category are minerals such as quartz, feldspars, and amphiboles.
B-l
-------
I
,mCCKT SAND
U. S. STANDARD SIEVE NUMBERS
JO ZO 4O 80 300
1 1 1 1 1 1 1 II 1 1 1 1
SAND
UI
UJ<
>o
o
OARSE
o
EDIUM
I
UJ
z
UL
>U1
K. z
UJ
>M-
SILT
CLAY
I I
JI1 I I I I
N. o o. q , 9 o S o
o o o o P P °.
GRAIN SIZE, mm o o o
Figure B-l.
Soil textural classes and general terminology
used in soil descriptions.
B-2
-------
The predominant oxide minerals are compounds of Fe, Al, and Mn. A sig-
nificant part of the Fe and Al oxides in soils may be present as amor-
phous rather than crystalline compounds, depending on soil pH, organic
matter content, and other properties. Amorphous compounds possess a
higher surface area and greater chemical reactivity than their crystal-
line counterparts, and can sorb trace metals such as Cd, Cu, Ni, Zn,
etc. It has been well established that Fe and Al compounds in soij are
important sites for P fixation. The solubility of Fe and AT5 in
soils is depressed with increasing pH. Since Fe and Mn can undergo oxi-
dation-reduction reactions, the forms and subsequent solubility of Fe
and Mn are influenced by soil aeration. Both Fe and Mn are more soluble
under reduced than under oxidized conditions.
The presence of alkaline earth carbonates in soil influence its pH and
buffering capacity. The pH of soils which contain excess carbonate
ranges from about 7.5 to 8.2 and is buffered at this level until carbon-
ates dissolve and leach downward in the soil profile. This results in
soils becoming acidic, and additional liming materials (limestone) may
have to be applied to promote crop growth, or, in the case of sludge ap-
plication, to maintain a pH at or above 6.5.
Organic matter is another important component of soils (i.e., humus).
There are two major categories of soil organic matter, namely, humic and
nonhumic substances. Nonhumic substances are the intact or partially
degraded compounds from plant, animal, or microbial residues. In gen-
eral, non-humic substances account for less than 25 percent of soil or-
ganic matter. With time these constituents decompose, and a portion of
the degradation products becomes incorporated into humic substances.
Humic substances are complex, high-molecular weight organic materials
that result from chemical and enzymatic reactions of organic degradation
products from plant, animal, and microbial residue. Humic substances
are subdivided into the following categories: fulvic acids (acid and
alkali soluble), humic acids (acid insoluble, alkali soluble), and humin
(acid and alkali insoluble). Although quantitative differences exist in
chemical composition, all three fractions are characterized by a nonpo-
lar (aromatic rings) core with attached polar functional groups. The
nonpolar nature of humics accounts for the strong affinity of soil or-
ganic matter for added organic compounds such as herbicides, pesticides,
etc. Functional groups found in soil organic matter include carboxyl (-
COOH), phenolic and alcoholic hydroxyl (-OH), amino (-NH2), and sulfhy-
dryl (-SH) groups. All of these functional groups exhibit acid-base
character, and soil organic matter is thus involved in the buffering of
soil pH. Furthermore, the ionization of the weakly acidic functional
groups results in soil organic matter possessing a net negative charge
or CEC. Soil pH strongly influences the CEC of soil organic matter with
increasing pH resulting in increasing CEC. Metals may also interact
with functional groups through chelation and ion exchange mechanisms.
Clay minerals and organic matter account for virtually all. soil CEC.
The CEC of soil organic matter normally ranges from 100 to 300 meq/100
g, whereas the CEC of clay minerals varies, according to the mineral
type, from 5 to 170 meq/100 g. Therefore, the relatively small fraction
B-3
-------
of organic matter present in a soil may exert a large influence on total
CEC.
A more comprehensive treatment of the items discussed under general
properties of soils can be obtained from a number of text books on the
subject (5, 14).
B.2 Nitrogen Transformations
A simplified schematic of the nitrogen cycle is shown in Figure B-2.
Both organic and inorganic nitrogen are added to soils by sludge addi-
tion. While the inorganic nitrogen (NH^+ and N03~) is readily available
for plant uptake, the organic nitrogen is not and must be converted to
inorganic forms to render it plant available. The rate at which organic
nitrogen is mineralized to plant-available inorganic nitrogen is highly
variable, and depends upon the physical and chemical properties of the
sludge applied, the physical and chemical properties of the soil to
which the sludge is applied, the temperature, and the water content of
the soil. Laboratory studies for net nitrogen mineralization rates dur-
ing the first growing season for different sludge types showed rates
which range from no net mineralization of the applied organic N (wet air
oxidation treated) to 58 percent (waste-activated sludge) (30). In gen-
eral, N mineralization rates were greatest for undigested primary and
waste-activated sludges and least for composted and heat treated
sludges. Essentially no net mineralization occurred where the carbon-
to-nitrogen (C/N) ratio of the sludge was greater than approximately 20.
Important soil properties influencing the mineralization rate of organic
nitrogen include temperature, water content, soil pH, and C/N ratio.
For mineralization, soil -water content of approximately 50 percent of
the water-holding capacity of the soil, soil pH values between 4.5 and
9.0, and C/N ratio in the amended soil less than about 20, are optimum.
Carbon-to-nitrogen ratios of the soil-sludge mixture of about 10 or less
are optimum for maximum N mineralization. In many sludge treated forest
soils the rate of. nitrification may be very slow, presumably because
these soils frequently have low'-soil pH and C/N ratios much greater than
20. Likewise, the rate of nitrification of sludge treated drastically
disturbed acid soils may be slow if the pH remains less than 4 following
sludge application.
Because of the wide variety of factors affecting nitrogen mineralization
rates for sludge applied to soil, it is advisable to determine rates on
a site- and sludge source-specific basis. As a guideline, for agricul-
tural soils, nitrogen mineralization rates, expressed as percent of
sludge organic N, are given in Table 6-7 (the "F" factor).
Ammonium-N (NH^-N) is a nitrogen compound added to soils in liquid
sludge applications. It may be held on the clay surface as an exchange-
able cation. In soils containing micaceous minerals, NH
between the mineral plates, causing collapse of the mineral and
fixation. This form of NH^-N is less reactive than exchangeable
* may
mineral
penetrate
H4+
and
B-4
-------
o
c:
i
HI
o
o
0)
en
o
S-
2:
CM
I
CO
O)
S-
cn
LL.
B-5
-------
soluble forms, but does in time undergo chemical and, microbial transfor-
mations.
Of importance, especially when considering surface application of
sludges, is NH3 volatilization. In situations where liquid sludges are
applied and not incorporated into the soil by injection, disking, or
plowing, essentially all of the NH^-N may be lost by volatilization.
Even where liquid sludge is incorporated into the soil, some of the NH*-
N may be lost by NH3 volatilization (28). The extent of NH3 volatiliza-
tion can not be generalized since it depends on any number of factors
including soil pH, soil CEC, climate (temperature, relative humidity),
and soil conditions (water content, rate of infiltration) and time lapse
between application and incorporation (30).
Laboratory experiments indicate that the extent of NH3 volatilization is
related inversely to CEC and directly to pH. Unfortunately, quantita-
tive data are not available concerning the magnitude of NH3 volatiliza-
tion under field conditions. At present, recommendations based on N ap-
plication rates assume .that 50 percent of the plant-available N i's lost
via NH volatilization when sludge is surface-applied.
After addition to soil, a large portion of the NH/1" will be converted to
nitrate (NOg"). This .process, called nitrification, involves two steps.
First, NH^"1" is oxidized to NO-" by the bacterium Nitrosomonas, followed
by oxidation of N02~ to N03~ T>y Nitrobacter. In neutral aerated soils
at temperatures greater than 15°C, essentially all NH/1" added will be
converted to N03~ within 2 to 4 weeks after application. Depressed ni-
trification rates may occur in soils at temperatures less than 10°C.
The formation of N03~ is significant, because N03~ can be lost from the
soil through leaching and denitrification. In humid regions, N applied
to soils in excess of crop requirements can leach and result in N03~
contamination of ground water. Systems developed for land application
of sludges are based on the premise that a growing crop will reduce the
N03~ concentratipn in the soil solution to levels which will result in
minimal environmental risks. Thus, in agricultural applications, the
annual amount of N in sludge applied to soils is based on the N required
by the crop grown.
In addition to leaching, N03" may be lost from soils through denitrifi-
cation. Denitrification occurs when facultative anaerobic bacteria uti-
lize N03~ as a terminal electron acceptor in place of 02 under anaerobic
conditions in the soil, i.e., saturated or excessive water contents. In
an "aerobic" soil, it is also possible that denitrification can be
occurring, because the center of soil aggregates may be water-saturated
and anaerobic. The end products of denitrification are NoO and No.
which diffuse into the atmosphere. Denitrification may be a significant
mechanism for N loss in soils treated with liquid sludge because of
localized increases in soil HUD content. Thus, NH4+ may be oxidized to
in an aerobic zone, followed by diffusion
microsites where denitrification occurs.
of
N03-
into anaerobic
B-6
-------
Certain adverse effects of overfertilization of soils with sewage sludge
may occur. The use of excess N can cause luxury consumption of N03" by
many plants, resulting in potential animal health problems when high
NOo" feedstuffs are consumed. The leaching of NOg" from the soil pro-
file could contaminate ground waters. Also, excessive nitrogen fertili-
zation may cause lodging of small grains resulting in harvesting prob-
lems and' reduced productivity.
The two areas of concern involving high concentrations of NOg" in waters
are direct health effects and surface water eutrophication. Excessively
high levels of nitrate-nitrogen in drinking water may present a health
hazard. Winton, Tardiff, and McCabe described the circumstances which
may induce methemoglobinemia or cyanosis in infants (35). The main con-
trolling factor in this disease is the daily nitrate intake; hence, the
nitrate concentration of drinking water plays an important role. Drink-
ing water standards in the United States specify the maximum permissible
concentration of nitrate-nitrogen as 10 mg NOg-N/l.
Livestock may suffer from a number of symptoms caused by excessive ni-
trate-nitrogen levels in the drinking water, including vitamin A defi-
ciency, reproductive difficulties and depressed milk production. In-
creased concentrations of N in surface water may also cause eutrophica-
tion, i.e., nutrient enrichment. Eutrophication results in rapid growth
of the nuisance aquatic plants, most commonly phytoplankton blooms. The
exact factors responsible for eutrophication are still insufficiently
understood; however, P concentrations below 0.01 mg/1 and N concentra-
tions below 0.2 to 0.3 mg/1 appear to minimize algal blooms in surface
waters.
B.3 Phosphorus Interactions
The behavior of phosphorus in soils is controlled by chemical rather
than biological reactions. The interactions of the phosphorus cycle, are
illustrated in Figure B-3. The majority of phosphorus in sludges is
present in inorganic compounds, about 70 to 90 percent of the total
phosphorus. Even though mineralization of the organic phosphorus occurs
during decomposition, inorganic reactions of phosphorus are of greater
importance in sludge application.
The available P for plants is present in the soil solution. As plants
deplete the soil solution P, the equilibria with sorbed P and P minerals
are shifted, resulting in replenishment of the soluble P pool. Thus,
the concentration of soluble P in soils may not be related to the abil-
ity of a soil to supply P to crops throughout the entire growing season.
Soils possess the ability to "fix" P through sorption and/or precipita-
tion reactions. As a result, a concentration of <0.1 mg P/l in the soil
solution generally results in minimal leaching losses of P. It has oc-
casionally been inferred that excess P in the soil impairs plant growth
via indirect action. For example, symptoms of Zn deficiency can be
traced to P inhibition at the root surface when soluble phosphates are
present. However, sludge applications add both P and Zn to minimize any
potential P-Zn interactions.
B-7
-------
Figure B-3. Phosphorus cycle in soil.
B-8
-------
B.4 Reactions of Metals in Soil
Land application of sludges will add appreciable amounts of trace metals
to soils. The metal content of soils and plants is quite variable de-
pending on the soil type and plant species. Trace elements such as B,
Co, Cu, Mn, Mo, Fe, and Zn are essential for plant growth; however, if
excessive concentrations are applied to soil, metal toxicities may de-
velop and crop yields may decrease. Often, the interpretation of metal
toxicity to plants is not straightforward because of interactions be-
tween nutrients, e.g., P-induced Zn deficiency. Nonessential metals,
e.g., Cd, Ni, under certain conditions may be harmful to plants and de-
crease yields. Of greater concern is the enrichment of food chain crops
with metals potentially harmful to humans and animals (As, Cd, Pb, Hg).
Because As, Pb, and Hg are not taken up by most plants from soils, the
element of greatest concern is Cd. In general, the rationale of sludge
application guidelines is to minimize phytotoxicity and decreased crop
yields caused by metal additions to soil, and excessive concentrations
of nonessential metals, e.g., Cd, in the plant part consumed by man or
animals. The fate of sludge metals in soils and plants has been exam-
ined in a number of review articles (8, 9, 20, 22).
. <*\- \J I IIH*. UUI.2 UVAVJ^-NA \f\J OI/11.J III .J ^YKW VJti OIUU^V. 1 -J VJ. C LJ I V> lr G VJ 111
Metals available to plants and susceptible to leaching are
he soil solution as the free metal ion (M ), complexes
The chemistry of metals in soils is quite complex and difficult to pre-
dict. The fate of metals added to soils in sewage sludge is depicted in
Figure B-4.
present in the
(MOH , MCI , etc.) and chelates (M-Fulvic acid, etc.). As plant uptake
or leaching occurs, the soil solution re-equilibrates with the solid
phase, resulting in a relatively constant concentration in the soil so-
lution. The equilibrium concentration will be controlled by soil prop-
erties such as pH, Eh, and solution composition. In general, the solu-
bility and plant availability of most metals decrease with increasing
pH.
Metals in the soil solution are continuously interacting: forming pre-
cipitates (carbonates, hydroxides, phosphates, etc.), interacting with
soil organic matter, being sorbed by clay minerals, and being retained
by hydrous oxides. Furthermore, the properties of clay minerals in soil
are influenced to a great extent by interaction with organic matter and
hydrous oxides. In general, the organic matter complexed with clay is
more resistant to decomposition than "free" organic matter, resulting in
the clay and organic matter contents of soils increasing proportion-
ately. The presence of acidic functional groups in soil organic matter
is responsible for metal retention through both exchange and chelation
mechanisms. Considerable evidence is accumulating concerning the impor-
tance of metal retention by Fe and Al hydrous oxides. Even where hy-
drous oxides are sorbed onto clay minerals, they still retain the abil-
ity to sorb metals. The Fe and Al hydrous oxide content of soils also
tends to increase with increasing clay content.
The trace metal retention capacity and CEC of soils both tend to in-
crease as the clay, hydrous oxide, and organic matter contents increase.
B-9
-------
Figure B-4.
p J.
Reactions of metals in soil (M represents
Cu, Zn, Ni, Cd, Pb, etc.).
B-10
-------
Because of these relationships, the CEC has been used as an index of the
metal retention capacity of a soil. This does not imply that metals
added to soils are retained through an ion exchange mechanism. Metals
present'in soil as exchangeable cations are available for plant uptake,
but only a small fraction of metals added to soil are present as ex-
changeable ions.
B.5 Trace Element Phytotoxicity and Plant Accumulation
Trace elements are ubiquitous in the geochemical environment. Their
concentrations in soils vary widely, and depend upon the chemical compo-
sition of the parent material, degree of mineral weathering, and soil
texture. In terms of their phytotoxic effects, the amounts present in
plant-available form are seemingly more important than the total quan-
tity in soils. The soil pH is the most important factor influencing the
availability of trace elements to plants. Except for Mo, the availabil-
ity of trace elements for plant uptake increases as the pH of the soil
decreases. Consequently, trace element phytotox.icities and accumulation
by plants are much more common on acid than neutral, alkaline, or cal-
careous soils. Plant species differ markedly in their tolerance to
trace elements. Therefore, it is not possible to develop criteria asso-
ciated with levels in soils that are applicable to all plant species.
Trace element accumulation may cause
health hazards to animals, including
Trace elements identified as
elements whose concentration
hazardous to humans and animals
Hg, Mn, Mo, Ni, Se, Sb, and Zn
and Zn are considered to pose
crops or the food chain (8).
soil in the form of sludge are considered
ard to crops and the food chain.
reduced crop yield or may pose
man, who may consume the crop.
potentially harmful to plant growth or as
in crops may reach levels considered to be
include: -AT, As, B, Cd, Cr, Cu, Fe, Pb,
(33). In general, only Cd, Cu, Mo, Ni,
a potentially serious hazard to either
The remaining elements when applied to
to pose relatively little haz-
B.5.1 Manganese, Iron, and Aluminum
The concentrations of manganese in most soils, and Fe and Al in virtu-
ally all soils, far exceed concentrations which may be applied from
sludges. Toxicities of Al and Mn occur only in acid soils, and are re-
lated to the concentrations of these elements in the soil solution.
Where plants suffer from either Mn or Al toxicity, the condition is
easily corrected through liming the soil to pH greater than 5.5. Iron
is considered to pose potential problems only when it occurs in elevated
levels in an active form and induces a deficiency of other essential
elements (P, Mn). Because current regulations require that the pH of
the sludge-treated soils used to produce food chain crops (except for-
est) be maintained at levels of 6.5 or greater, Al, Fe, and Mn should
pose no hazard.
B-ll
-------
B.5.2 Chromium
Total chromium in soils usually varies from 50 to 3,000 mg/kg, with
typical levels being about 100 mg/kg (22). The Cr naturally present in
soils is quite inert. Most crops (except for a few indicator plants)
grown on soils which contain high levels of Cr do not appear to absorb
Cr much in excess of those grown on soils low in Cr. The two principal
oxidation states of Cr are Cr(III) and Cr(VI) forms. The Cr(III) form
is most common in soils, and when Cr(VI) (as CrO^~ and CrpOy=) is added
to soils, it is rapidly reduced to the Cr(III) form. Cr(Vi) in soils is
absorbed by plants, and has been shown to be phytotoxic (26). The phy-
totoxic effect, however, is temporary and related to the rate at which
Cr(VI) is reduced to Cr(III). Studies involving cropland application of
sewage sludge containing substantial quantities of Cr have not resulted
in reduced crop yield, or substantially increased the concentration of
Cr in plant tissue (10). Based on available information, it is doubtful
that Cr added to soil from sludges will damage crops, and no problems
have been reported in the literature.
B.5.3 Arsenic and Antimony
Inorganic arsenicals have been used as insecticides and herbicides for
many years, and certain soils have been seriously contaminated with
these elements. Inorganic arsenical pesticides were banned in the
United States in 1967 and have been replaced by the organic arsenicals
(monosodium methanearsonate, disodium methanearsonate, and cacodylic
acid). Most information on the potential detrimental effects of As in
soils comes from the study of sites highly contaminated by pesticide
use. Soils of apple and pear orchards where trees have been treated re-
peatedly with large amounts of arsenical pesticides contain sufficient
As to damage many plant species (3). The residual As in the contami-
nated soils where phytotoxicities were observed was usually greater than
100 kg As/ha, and in many cases was greater than 200 kg As/ha. However,
phytotoxicity was not necessarily directly related to the total As pres-
ent in the soil, but to available Fe, Al, Ca, organic matter, soil tex-
ture, and susceptibility of the plant variety. Phytotoxicities associ-
ated with As are more likely to occur in coarse-textured soil with a low
capacity to adsorb As. When grown on these soils, legumes have been
shown to be sensitive to elevated levels of As in the soil. Rye and
sudangrass, on the other hand, were quite tolerant. The concentrations
of As in sewage sludge range from 3 to 30 mg/kg (see Appendix A, Table
A-6). If one assumes a concentration of 25 mg As/kg sludge and 100 kg
As/ha to cause phytotoxicity, 4,000 tons of sludge would have to be ap-
plied before levels in soil associated with phytotoxicity are reached.
It is doubtful, therefore, that As levels in sludge-treated soils would
reach potentially harmful levels unless sludge were applied continuously
century. The amounts of As absorbed by plants
soils are not considered to be sufficiently
a hazard to consumers.
at high rates for about a
grown on sludge amended
great to present
B-12
-------
Concentration ranges of Sb common to natural soils are not well estab-
lished. In the earth's crust, concentrations are usually less than 1 mg
Sb/kg. Concentrations of Sb in sewage sludges from 16 cities in the
United States vary from 2.6 to 44.4 mg Sb/kg sludge, "with a median con-.
centration of 10.8 mg Sb/kg (12). These concentrations are quite similar
to concentrations of As which occur in the same sewage sludges. Because
the chemistry of Sb is quite similar to that of As, and their concentra-
tions in sewage sludges are approximately the same, a phytotoxic problem
produced by Sb is also highly unlikely.
8.5.4 Lead and Mercury
Lead is a nonessential element which typically occurs in soils at a mean
concentrations of 10 to 15 mg Pb/kg of soil (22). It has been applied
to soils in very large amounts (greater than 500 kg/ha) with no apparent
phytotoxic effects (2, 29). Soluble forms of Pb added to soil rapidly
react with other chemical constituents in soils to form quite insoluble
compounds; hence, leaching of Pb through soils to ground waters is un-
likely. Typically, Pb concentrations of sludges are substantially
greater than in soils; with repeated applications, enrichment of surface
When ingested in excessive quantities by humans,
However, it is unlikely that Pb applied to soil
absorbed by plants and subsequently by humans. A
poisoning of large animals caused by the inges-
particles contaminated by industrial emissions
soil with Pb occurs.
Pb is highly toxic.
with sludges will be
number of cases of lead
tion of forage and soil
of Pb have been reported (6, 13). Since repeated applications of
sludges may cause substantial enrichment of surface soils, care should
be taken to ensure that foraging animals avoid excessive consumption of
soil.
Mercury, like Pb, can be harmful to the health of human beings when ex-
cessive amounts are ingested. Although aboveground parts of plants can
be injured by Hg vapor, there is no evidence linking soil-applied Hg to
phytotoxicity. Crops absorb only trace amounts of Hg through their root
systems, therefore Hg absorption by plants grown on sludge amended soils
is of little concern.
B.5.5 Selenium and Molybdenum
Selenium concentrations of sludges are frequently below levels detected
by routine analytical procedures. Therefore, data for the Se content of
sludges are not readily available. Its concentration in soil normally
ranges from 0.1 to 2 mg Se/kg, with the typical level being 0.2 mg Se/
kg. Although Se applied to soils is readily absorbed by crops, it does
not appear to adversely affect crop growth.
Plants tend to respond to Mo applications to soils in a manner similar
to their response to Se. It has been reported that large quantities of
Mo may be added to soils with little effect on growing plants (18).
B-13
-------
Elevated concentrations of Mo and Se in foods are not considered harmful
to the health of human beings. High concentrations in livestock feed,
however, can be harmful to the health of animals. A number of crops
grown in soils high in Mo and Se will absorb sufficient amounts of these
elements to cause either impaired health or metabolic imbalance in ani-
mals that consume the plants.
As a micronutrient element, Mo is required in small amounts by plants,
and is also essential at low concentrations in the diet of animals. In
animal diets, particularly of ruminant animals, concentrations of Mo as
low as 5 mg Mo/kg may be toxic (1). The occurrence and severity of Mo
toxicity are directly related to the amounts of Mo ingested relative to
that of Cu and SO^. High Mo and low Cu levels in forage constitute the
most serious combination. In fact, Mo toxicity, molybdenosis, is fre-
quently referred to as an Mo-induced Cu deficiency. It is not possible
to specify levels of Mo in soils that would produce forage unfit for
animal consumption, because the amounts of Mo absorbed by crops vary
with soil properties. Generally, the availability of Mo to crops in-
creases as the pH of the soil increases; the availability of Cu to crops
usually decreases as the pH of the soil increases. Molybdenum toxicity
to livestock animals is therefore more commonly associated with forage
grown on alkaline soils.
Sewage sludge contains Mo in amounts which range from 5 to 39 mg/kg,
with typical levels being 28 mg/kg. Although repeated applications of
sludge to soils might potentially produce forage unfit for consumption
by livestock, no reports of this effect appear in the literature. For
Mo toxicity to develop in animals, high Mo and low Cu forage must be
their sole source of feed. Since it is unlikely that feed from sludge-
treated soils would comprise the entire diet of an animal, the possibil-
ity of Mo toxicity to animals traced to forage grown on sludge-treated
soils seems remote.
While Se is not considered to be essential for the growth of higher
plants, it is required in small amounts in the diet of animals. Like
Mo, the margin between Se deficiency and toxicity in animal diets is
narrow. Malnutrition in animals, caused by deficient levels of Se in
their diets, is frequently reported in the United States and other parts
of the world. Levels in animal diets which range from 0.04 to 0.2 ug
Se/g have been associated with a deficiency (1). Selenium deficiency
levels depend upon the kind of animal and the type of diet. Selenium
deficiency is frequently associated with a Vitamin E deficiency and cor-
rection of Se deficiency in lambs and calves has routinely involved in-
jections of Se and Vitamin E.
In areas where soils are naturally high in Se, certain plant species are
capable of accumulating Se to levels considered unsafe for animal con-
sumption. Selenium levels in forage exceeding 4 mg Se/kg (oven-dry
weight, 70°C) are considered potentially toxic (1). Concentrations of
Se in soils normally range from 0.01 to 2.0 mg Se/kg soil. At compar-
able levels in soil, amounts of Se absorbed by plants grown on neutral
B-14
-------
and calcareous soils are usually
plants grown on acid soils.
greater than quantities absorbed by
The data base to quantify concentrations of Se in sewage sludge is too
limited to be generalized. Published data on sludges from 16 metropoli-
tan areas suggest that Se concentrations in sludges generally exceed
those typically found in natural soil (12). Prolonged use of certain
sludges on soils would therefore be expected to cause some Se enrichment
to soil. However, no indication 'of sludge-borne enrichment of Se in
soil leading to crop or animal health problems have been reported in the
literature. '
B.5.6 Copper and Nickel
The concentrations of both Cu and Ni in natural soils are highly vari-
able. Because of their ubiquitous nature and common use, these elements
are always present in sewage sludges.
Copper concentrations in soils range from 2 to 100 mg Cu/kg soil, with
typical levels being 40 mg Cu/kg soil. Copper is essential to the
growth of plants, and occurs in plants at concentrations which usually
range from 5 to 20 mg Cu/kg. In acid soils which have naturally high
levels of plant-available Cu, and in soils where Cu has been applied in
large amounts, it can be phytotoxic. The tolerance of plants to Cu in
soil, as with other elements, varies among species. It has been recom-
mended that Cu additions to soil in the form of sewage sludge not exceed
125, 250, and 500 kg Cu/ha in soils with CEC's of <5, 5 to 15, and >15
meq/100 g, respectively (33). The input limits are recommended fbr
soils maintained at pH >6.5.
Although chronic Cu poisoning may occur in animals under natural grazing
conditions, the problem is related to the dietary intake of Cu as well
as Zn, Fe, Ca, Mo, S, and Cd (1, 32). Also, it is not necessarily re-
lated to Cu intake from forage alone, since considerable quantities of
soil material may be ingested by grazing animals, and contributions of
Cu from this source may be substantial (15). Sheep appear to be the do-
mestic animal most sensitive to excessive amounts of Cu in the diet
(32). No instances of Cu poisoning of animals grazing on sludge-treated
soils,have been reported. However, because copper could accumulate in
the surface of highly sludge-treated soils, it may be possible that ani-
mals could ingest sufficient Cu to cause toxicity.
Nickel contents of natural
'soils vary from about 10 to 4,000 mg Ni/kg,
with typical levels being 40 mg Ni/kg (22). While Ni
to be essential for the growth of higher plants, it
growth of animals. Like Cu, Ni
on acid soils. Yield reductions
sludge applied to acid
United States (25, 34).
sensitivities to Ni concentrations in soil, levels greater than 40 kg
Ni/ha in soils with pH values less than 5.5 may damage some crops such
is not considered
-. ....,.._. r , ,. is essential for the
i toxicities to plants normally occur only
;ions . associated with Ni ,in the form of
soils have been reported in England and the
Although plant species .vary markedly in their
B-15
-------
as oats, clover, potatoes, turnips, cabbage, and beets (25). Toxic
els for neutral, alkaline, and calcareous soils are much higher.
soils with pH values greater than 6.5, it has
additions to soil in the form of sludge not
Ni/ha in soils with CEC's of <5, 5 to 15,
tively (33)..
Toxic lev-
For
been recommended that Ni
exceed 125, 250, and 500 kg
and >15 meq/100 g, respec-
Nickel is a relatively nontoxic element to animals, and Ni contamination
of foods does not present a serious health hazard (32).
B.5.7 Cadmium and Zinc
Cadmium and Zn may reach phytotoxic levels under a wide range of soil
chemical conditions. Plants grown on all soils appear to respond to the
increased concentrations of these metals in soils with accelerated ab-
sorption. Cadmium and Zn phytotoxicity usually occurs at lower concen-
tration levels in acid than in neutral or calcareous soils. Because Cd
has the potential to present more problems in soils than other trace
metals and Zn-Cd interactions and associations are common, these have
been studied extensively.
Concentrations of Cd which occur in native soils normally range from
0.05 to 1.5 mg Cd/kg soil, with a typical level of 0.3 Cd/kg (23). Cer-
tain soils in California and elsewhere derived from shale parent mate^
rial, however, contain unusually high levels of indigenous Cd (5 to 20
mg Cd/kg) (21). Although the Cd absorption characteristics of plants
are not completely understood, available information shows that the con-
centration of Cd in the leaf tissue of plants tends to increase as the
amount of Cd added to soil increases. The reproductive parts of plants
(flowers, fruits, seeds) usually contain lesser concentrations of Cd,
and respond less rapidly to Cd additions to soils than do vegetative
parts. The phytotoxic tolerance of plant species to Cd added to soil
and the amounts accumulated by various plant species are also highly
variable.
Both the annual and cumulative total Cd input limits (0.5 to 2.0 kg Cd/
ha, and 5 to 20 kg Cd/ha, respectively) that have been suggested for
cropland application of sludges were intended to prevent elevated levels
of Cd in food, and are much more conservative than levels associated
with possible phytotoxicity. Available information indicates that the
limits suggested by the EPA to stop the entry of Cd into the food chain
are adequate to protect against Cd phytotoxicity to all crops.
The entry of Cd into the human and animal food chain from the use of
wastewater sludges on agricultural land is considered by many to be the
most critical problem related to the trace metal content of sludges.
According to various estimates and surveys, the estimated daily dietary
intake of Cd in the United States is approximately 1/3 to 1/2 of the
maximum daily intake of Cd proposed by the Food and Agricultural Organi-
zation and the World Health Organization (36). Although there are no
documented human health problems traced to sludge application to soils,
B-16
-------
there is clinical evidence from Japan that links Cd poisoning to the
consumption of rice grown on soil contaminated by wastewater originating
from nearby Zn smelting operations (31). Persons suffering from chronic
Cd poisoning consistently derived a substantial percentage of their die-
tary rice from the contaminated fields, and consumed this rice daily for
30 to 50 years. Daily, exposure to food containing elevated concentra-
tions of Cd resulted in gradual accumulations in the bodies of the af-
fected population so that symptoms of Cd toxicity later became evident.
Preventive measures taken since the peak of the epidemic in the early
1950's have substantially reduced the number of new cases of Cd poison-.
ing in the affected regions.
A number of studies in the United States and other parts of the world
have shown that where sewage sludges containing Cd are applied to agri-
cultural soils, the concentration of Cd in many crops grown on the sites
is increased (7, 8, 9, 20, 22). However, the percent of cropland in the
United States that has received sewage sludge is very small. Even if
all sludges generated in the United States were to be used on agricul-
tural soils as a source of nitrogen fertilizer, less than 1 percent of
the agricultural land in the United States would be affected (8). Sta-
tistically, there is only a remote probability that any one person would
consume foods elevated in Cd from the marketplace over a period of time
sufficient to cause excessive exposure. However, misuse of sludge con-
taining relatively high concentrations .of Cd could conceivably lead to
excessive Cd in food, and subsequent health problems.
Typical levels of Zn in soils are 50 mg Zn/kg. Zinc is an element es-
sential for the growth of plants, and deficiencies of plant-available Zn
in soil are frequently encountered. Sludge applications could therefore
be beneficial in correcting Zn deficiencies in some soils.
Although high concentrations of Zn in any soil could result in phytotox-
icities, the occurrence and impact of Zn toxicity is most severe for
plants grown on acid soils. Suggested limits for Zn application to
soils from sludge application are 250, 500, and 1,000 kg Zn/ha for soils
with CEC's of <5, 5-10, and >15 meq/100 g, respectively (33).
Among the divalent metals, Zn is of a relatively low toxicity. Chronic
toxicity to man from dietary sources of Zn is highly unlikely (32).
B.5.8 Boron
Relative to the other
application of sludge
largely in the form of
trace elements discussed, the role of B in land
is somewhat unique. In wastewaters, B occurs
Being uncharged,
undissociated boric acid
noL>UO
it passes through soils much more readily than do ne other trace ele-
ments. Although B is essential for crop growth, when present in soil
solutions at concentrations greater than 1.0 mg/1, it is highly toxic to
many plants. The margin between levels considered essential to plant
growth and those considered phytotoxic is usually very narrow. Plants
grown on soils whose level of water-soluble boron is less than 0.04 mg
B-17
-------
B/l often exhibit B deficiency symptoms while at concentrations in ex-
cess of 1.0 mg B/l, B is toxic to sensitive species (4, 11). The,con-
centrations of B in saturation extracts from soils known to damage a
wide variety of crops are quite well documented, and tolerance levels
are readily available (27).
Although the other elements previously discussed (Cr, Fe, Mn, Ni, Cu,
Zn, Se, Mo, As, Hg, Pb, Sb, Cd, and Al) all tend to accumulate in the
surface of soils following application, B is only weakly adsorbed by
soils, and readily passes through them with leaching water. In arid and
semi arid regions, the B in the sludges may have an adverse impact on
plant growths, but cumulative effects are not as marked as with the other
trace metals. In humid and semihumid regions, rainfall is usually suf-
ficient to leach applied B from the root zone to harmful levels.
Boron has a low order of toxicity when administered orally (32). The
possibility that crops grown on sludge-treated soils would accumulate
concentrations of B potentially harmful to animals and humans is highly
remote.
B.6 Organics
The concentration of organics, such as chlorinated hydrocarbon pesti-
cides and polychlorinated biphenyls (PCB's), can be elevated above back-
ground levels (<10 ppm) in sewage sludges from cities receiving wastes
from industrial discharges of these organic compounds. The potential
impact of organic compounds on land application practices has been dis-
cussed recently by Pahren, et a!., and Jelinek and Braude (24, 19).
Very little research has been conducted on the uptake of organics by
crops growing on sludge-treated soils; the following discussion empha-
sizes data obtained from related experiments. Pesticide and PCB levels
in sludges are shown in Table B-l.
In general, a minimal amount of pesticides is sorbed by plants and
translocated to aerial parts. For example, the foliage of corn contains
less than 3 percent of the dieldrin applied to soil, while the concen-
tration in the roots is appreciably greater. Nearly all pesticides are
relatively nonpolar molecules which are strongly bound by soil organic
matter and to the surface of plant roots. Thus, the concentration of
pesticides in root tissue does not result from typical uptake mechanisms
where the molecule must permeate the membranes of root cells.
The uptake of PCB's has been evaluated using carrots as the test crop
(16). Soils treated with Aroclor 1254 at 100 mg/kg produced carrots
containing from 2 to 30 mg PCB/kg, depending upon the examined component
of the PCB mixture. More significantly, 97 percent of the PCB residue
was found in carrot root peelings, only 14 percent of the carrot weight.
These results suggest that PCB's are not actually taken up by carrots,
but are physically adsorbed on the surface of carrot roots. Additional
evidence supporting the inability of plants to accumulate organics was
obtained by Jacobs, Chou, and Tiedje, who grew orchardgrass and carrots
in soils treated with 10 and 100 mg/kg of polybrominated biphenyls
B-18
-------
(PBB's) (19). At these rates, the amount of uptake of PPB's was essen-
tially nondetectable (20 to 40 ug/kg) in carrots, and nondetectable in
orchardgrass. It should be emphasized that the rates used in these
studies far exceed those expected from sludge application. In general,
plants exclude the majority of organics added to soils, resulting in
minimal impact on the quality of forages and grains. Furthermore, even
though PCB's and related compounds resist microbial degradation, they
are slowly decomposed after incorporation in soils.
TABLE B-l
PESTICIDE AND PCB CONTENT OF DRY SLUDGES (24)
Range (mg/kg)
Number of
Compound
Aldrin*
Dieldrin#
Chlordane*
DDT + DDD*
PCB's**
Minimum
NDt
<0.03
3.0
O.I
ND
Maximum
16.2
2.2
32.2
1.1
352.0
Sludges Examined
5
21
7
. 7 '
83
* Examined in 1971.
t Nondetectable.
# Examined in 1971, 1972, 1973.
** Examined in 1971, 1972, 1973, and 1975.
A potential problem arising from organics in sludge is direct ingestion
by animals grazing on forages treated with a surface application of
sludge. Most organics are concentrated in fatty tissues and fluids
(butterfat). Even though rains may remove the majority of sludge adher-
ing to forages after a surface application of sludge, a sufficient
amount of sludge may remain, resulting in direct ingestion of organics
by cattle. For this reason, Pahren, et al., suggested that sludges sur-
face-applied to grazed forages contain no more than 10 mg/kg of PCB's
(24). This problem can be eliminated for sludges containing over 10
mg/kg PCB by incorporation of the sludge into the soil prior to planting
forage crops.
B7.0 References
1. Allaway, W. H. Agronomic Controls Over the Environmental Cycling
of Trace Elements. Adv. Agron., 20:235-274, 1968.
2. Baumhardt, G. R., and L. F. Welch. Lead Uptake and Corn Growth
with Soil Applied Lead. J. Environ. Qual., 1:92-94, 1972.
B-19
-------
3. Benson, N. R. Effect of Season, Phosphate, and Acidity on Plant
Growth in Arsenic-Toxic Soils. Soil Sci., 76:215-224, 1953.
4. Bingham, F. T. Boron in Cultivated Soils and Irrigation Waters.
In: Trace Elements in Environment. Adv. Chem. Ser., 123:130-138,
1973.
5. Brady, N. C. The Nature and Properties of Soils. Macmillan, New
York, 1974.
6. Chaney, R. L. Agents of Health Significance: Toxic Metals. In:
Sludge-Health Risks of Land Application. G. Bitton, B. L. Damron,
G. T. Edds, and J. M. Davidson, eds. Ann Arbor Science, Ann Arbor,
Michigan, 1980. pp. 59-84.
7. Chaney, R. L., and P. M. Giordano. Microelements as Related to
Plant Deficiencies as Related to Plant Deficiencies and Toxicities.
In: Soils for Management of Organic Waste and Wastewaters. L. F.
Elliott and F. J. Stevenson, eds. Soil Science Society of America,
Madison, Wisconsin, 1977. pp. 234-279.
8. Council for Agricultural Science and Technology. Application of
Sewage Sludge to Cropland: Appraisal of Potential Hazards of the
Heavy Metals on Plants and Animals. EPA-430/9-76-013, Ames, Iowa,
November 1978. 141 pp. (Available from National Technical Infor-
mation Service, Springfield, Virginia, PB-264 015)
9. Council for Agricultural Science and Technology. Effects of Sewage
Sludge on the Cadmium and Zinc Content of Crops. EPA-600/8-81-003,
Ames, Iowa, February 1981. 91 pp. (Available from National Tech-
nical Information Service, Springfield, Virginia, PB81 181596)
10. Cunningham, J. D., D. R. Kenney, and J. A. Ryan. Yield and Metal
Composition of Corn and Rye Grown on Sewage Sludge Amended Soil.
0. Environ. Qual., 4:455-460, 1975.
11. Eaton, F. M. Deficiency, Toxicity, and Accumulation of Boron in
Plants. J. Agric. Res., 69:237-277, 1944.
12. Furr, A. K., A. W. Lawrence, S. C. Fong, M. C. Grandolfo, R. A.
Hofstader, C. A. Bache, W. HY. Gutenmann, and D. J. Lisk. Multi-
El ement and Chlorinated Hydrocarbon Analyses of Municipal Sewage
Sludges of American 'Cities. Environ. Sci. Techno!., 10:683-687,
1976.
13. Hammond, P. B., and A. L. Aronson. Lead Poisoning in Cattle and
Horses in the Vicinity of a Smelter. Ann. N.Y. Acad. Sci., 3:595-
611, 1964.
14. Hausenbuiller, R. L. Soil Science - Principles and Practices.
C. Brown Co., Dubuque, Iowa, 1972.
Wm.
B-20
-------
15. Healy, W. B. Ingested Soil as a Source of Elements to Grazing Ani-
mals. In: Trace Element Metabolism in Animals. W. G. Hoekstra,
J. W. Suttie, H. E. Ganther, and W. Mertz, eds. University Park
Press, Baltimore, Maryland, 1974. Vol. 2, pp. 448-450.
16. Iwata, Y., F. A. Gunther, and W. E. Westlake. Uptake of a PCB
(Arochlor 1254) from Soil by Carrots Under Field Conditions. Bull.
Environ. Contam. Toxicol., 11:523-528, 1974.
17. Jacobs, L. W., S. Chou, and J. M. Tiedje. Fate of Polybrominated
Biphenys ,(PBB's) in Soils: Persistence and Plant Uptake. J.
Agric. Food Chem., 24:1198-1201, 1976.
18. Jarre! 1, W. M., A. L. Page, and A. A. Elseewi. Molybdenum in the
Environment. Residue Rev., 74:1-43, 1980.
19. Jelinek, C. F., and G. L. Braude. Management of Sludge Use on
Land, FDA Considerations. In: Proceedings of the Third National
Conference on Sludge Management, Disposal, and Utilitization, Miami
Beach, Florida, December:1976. pp. 35-38.
20. Kirkham, M. B. Trace Elements in Sludge on Land: Effects on
Plants, Soils, and Groundwaters. In: Land as a Waste Management
Alternative. R. C. Loehr, ed. Ann Arbor Science, Ann Arbor, Mich-
igan, 1977. pp. 209-247.
21. Lund, L. J., E. E. Betty, A. L. Page, and R. A. Elliott.- Occur-
rence of Naturally High Cadmium Levels in Soils and Its Accumula-
tion by Vegetation. J. Environ. Qual., 10:551-556, 1981.
22. Page, A. L. Fate and Effects of Trace Elements in Sewage Sludge
When Applied to Agricultural Soils: A Literature Review. EPA-
670/2-74-005, University of California, Riverside, January 1974.
107 pp. (Available from National Technical Information Service,
Springfield, Virginia, PB-231 171)
23. Page, A. L., A. C. Chang, G. Sposito, and S. Mattigod. Trace Ele-
ments in Wastewater: Their Effects on Plant Growth and Composition
and Their Behavior in Soils. In: Modeling Wastewater Renovation
Land Treatment. I. K. Iskander, ed. Wiley Interscience, New York,
1981. pp. 182-222.
24. Pahren. H. R., J. B. Lucas, J. A. Ryan, and G. K. Dotson. Health
Risks Associated with Land Application of Municipal Sludge. J.
Water Pollut. Control Fed., 51:2588-2601, 1979.
25. Patterson, J. B. E. Metal Toxicities Arising from Industry. G. B.
Ministry of Agric., Fish., and Food. Tech. Bull., 21:193-207, 1971.
26. Pratt, P. F. Chromium. In: Diagnostic Criteria for Plants and
Soils. H. D. Chapman, ed. Riverside, California, 1965. pp. 136-
141.
B-21
-------
27. Richards, L. A., ed. Diagnosis and Improvement of Saline and
Alkali Soils. Handbook No. 60, U. S. Dept. of Agriculture, Wash-
ington, D.C., 1954.
28. Ryan, J. A., and D. R. Keeney. Ammonia Volatilization from Surface
Applied Sewage Sludge. J. Water Pollut. Control Fed., 47:386-393,
1975.
29. Sabey, B. R., and W. E. Hart. Land Application of Sewage Sludge.
I. The Effect on Growth and Chemical Composition of Plants. J.
Environ. Qual., 4:252-256, 1975.
30. Sommers, L. E., C. F. Parker, and G. J. Meyers. Volatilization,
Plant Uptake, and Mineralization of Nitrogen in Soils Treated with
Sewage Sludge. Technical Report 133, Purdue University Water Re-
sources Research Center, West Lafayette, Indiana, 1981.
31. Tsuchiya, K., ed. Cadmium Studies in Japan: A Review. Elsevier/
North Holland Biomedical Press, New York, 1978.
32. Underwood, E. J. Trace Elements in Human and Animal Nutrition.
4th ed. Academic Press, New York, 1977.
33. Municipal Sludge Management - Environmental Factors.
Register, 41:22531-22543, 1976.
Federal
34. Valdares, M. 6., M. Gal, U. Mingelgrin, and A. L. Page. Some Heavy
Metals in Soils Treated with Sewage Sludge; Their Effects on Yield
and Their Uptake by Plants. J. Environ. Qual. (In Press).
35. Winton, E. F., R. G, Tardiff, and L. J. McCabe.' Nitrate in Drink-
ing Water. J. Am. Water Works'Assoc., 63:95-98, 1971.
36. World Health Organization. Environmental Health Criteria for Cad-
mium. Amsterdam, 1975.
B-22
-------
APPENDIX C
SAMPLING AND ANALYTICAL METHODS
C.I General
This appendix provides guidance in selecting methods for sampling and
analysis of sludge, soils, plants, ground water, and surface water as
may be necessary for,design and/or monitoring of sludge to land applicar
tion systems. The person selecting methods should also consult with the
cognizant regulatory agency and with knowledgeable individuals at the
local University Agricultural Extension Service, since regulatory re-
quirements and applicable methods for local conditions vary geographi-
cally.
As discussed in Chapter 11, and elsewhere in
ber, frequency, etc., of samples and analyses
between different projects. This appendix
should constitute the sampling and analysis
cusses methods available if certain types of
required.
C.2 Soils,
the manual, the type, nurn-
necessary will vary widely
does not stipulate what
program; rather, it dis-
sampling and analysis are
C.2.1 Purpose of Soil Sampling and Analysis
Soils can be sampled and analyzed at potential sludge application sites
as part of the site selection process (see Chapter 4). .More extensive
soil testing may be conducted after a final site(s) selection has been
made in order to establish baseline data. -In addition, soil monitoring
is periodically conducted at many sludge application sites after sludge
application has been initiated and the program is in full operation.
The purpose of soil testing prior to sludge
help determine site suitability. The soil
usually include the following:
application is primarily to
characteristics of interest
pH; a soil pH of 6.5, or above, is desirable, and often re-
quired by regulatory agencies, to minimize migration of heavy
metals.
Lime requirement; if soil pH is too low, lime additions can be
used to raise soil pH to a proper level. The soil can be
tested to determine the quantity of lime required.
Plant available nutrients, i.e., N, P, and K; existing soil
nutrient levels which are plant available is useful informa-
tion in calculating sludge application rates to the sludge ap-
plication site when growing vegetation on the site.
C-l
-------
CEC; is an indication of the soil's ability to tie up heavy
metals and prevent their migration. Regulations existing in
1982, use soil CEC as a guide in setting limits upon cumula-
tive heavy metal loading in the sludge application to sites
used for crops.
a Soil permeability and texture (particle size distribution);
provides guidance in determining the site drainage character-
istics. As discussed in Chapter 4 and Appendix B, it is gen-
erally desirable that a sludge application site is moderately
permeable, i.e., not so impermeable, as to cause surface mois-
ture ponding and not too permeable which may -result in rapid
subsurface migration of sludge constraints.
C:N ratio; it has been suggested that for forest soils, which
often have a high C:N ratio, this ratio is useful in estimat-
ing the tnitrogen storage capacity of the soil as it effects
the sludge application rate calculation. See discussion in
Chapter 7.
After the sludge application program is underway, it may be necessary or
desirable to monitor the changes occuring in the soil characteristics of
the application site. This is usually not done for typical agricultural
utilization projects where sludge is applied to farmland, at agronomic
rates, or below. Nor is routine post sludge application soil monitoring
usually done for forest land or land reclamation sludge utilization when
a one-time application is used, or sludge applications are at low rates
commensurate with vegetation nutrient requirements. Generally, periodic
soil monitoring of the sludge application site is done primarily when
one or more of the following situations exist:
1.
2.
3.
The sludge contains significant quantities of one or more heavy
metals or priority persistent organics. In this case, the soil
concentration of the sludge constituents of concern can be mon-
itored.
Heavy sludge application rates are used, as with
disposal site, and there is concern that the .soil
phytotoxic to vegetation grown on the site.
a dedicated
will become
The cognizant regulatory agency requires certain periodic soil
monitoring. For example, the regulatory agency may require an-
nual pH analysis to ensure that the soil pH remains above 6.5.
4. Research purposes. If demonstration projects, test plots,
etc., are being implemented, extensive soil testing is often
conducted to increase knowledge of the interaction between
sludge constituents and soil systems. ,
C-2
-------
C.2.2 Soil Sampling Procedures
Soils expertise is required to conduct and interpret an adequate soil
sampling program because of the potential variables involved, including
horizontal and vertical soil variations, size of the application
site(s), and the objectives of the soil sampling program. Advice should
be obtained from the University Cooperative Extension Service, County
Agricultural Agents, and/or others with expertise in sampling and analy-
sis of soils in the sludge application site(s) locality.
The number and location of samples necessary to adequately characterize
soils prior to sludge application is primarily a function of the spatial
variability of the soils at the site. In heterogenous materials, such
as mine spoils, an adequate determination of conditions may require sam-
pling on a grid pattern of some 30 m (100 ft) over the entire site.
Conversely, if the soil types occur in simple patterns sampling of each
major type can provide an accurate picture of the soil characteristics.
Often, existing soils maps (e.g., from the Soil Conservation Service)
and field visual observations provide an indication of the variability,
location, and extent of each.major soil type at the site.
In some states, the state regulatory agency stipulates the minimum num-
ber of soil borings which must be analyzed. New Jersey, for example,
stipulates the minimum number of soil borings required based on proposed
sludge application site area, ranging from a minimum of 3 borings on
small sites (up to 4 ha; 10 ac) to 24 borings on large sites (over 80
ha; 200 ac).
The depth to which the soil profile is sampled and the extent to which
each horizon is vertically subdivided depend largely on the parameters
to be analyzed, the vertical variations in soil character, and the
objectives of the soil sampling program. Typically, samples are taken
from each distinct soil horizon down to a depth of 120 to 150.cm (4 to 5
ft). For example, samples may be taken from four soil depths (horizons)
as follows: 0 to 15 cm (0 to 6 in), 15 to 45 cm (6 to 18 in), 45 to 75
cm (18 to 30 in), and 75 to 120 cm (30 to 42 in). Usually, as a mini-
mum, samples,are at least taken from the upper soil layer, e.g., 0 to 15
cm (0 to 6 in), and a deeper soil horizon, e.g., 45 to 75 cm (18 to 30
in). Samples taken from similar soil horizons are usually composited
for several borings located near each other in homogeneous soil. The
composited samples are subsequently analyzed.
The proper selection of tools for soil sampling depends in part on the
texture and consistency of the soil, the presence or absence of rock
fragments, the depth to be sampled, and the degree of allowable surface
soil disturbance. Soil samples are most accurately taken from a freshly
dug pit. However, where field plots are to be sampled periodically,
preferable sampling tools are those which disturb the plot the least.
Cutaway soil sampling tubes, closed cylinder augers, and tiling spades
(sharp-shooter) may be used depending upon the size of the plot and
allowable disturbance. The cutaway soil sampling tube creates the least
C-3
-------
disturbance, and works well in the plow layer and the upper subsoil of
moist, stone-free friable soils. Each sample collected should represent
the cross section of the soil layer being sampled.
In sampling subsurface soils, care must be taken to remove loose parti-
cles or sludge residue on the soil surface around the hole prior to and
during sampling. In addition, any surface soil/sludge residue attached
to the top and side of the core samples from lower depths should be re-
moved by slicing with a knife. It is recommended that the holes be
sealed by filling with bentonnite pellets and tap water. A map showing
samples points should be made.
C.2.3 Soil Sample Preservation
Samples should be air-dried (at temperatures less than 40°C), ground,
and passed through a 2-mm sieve as soon as possible after collection.
Chemical analyses are generally performed on air-dried samples, and do
not require special preservation for most parameters. However, samples
collected for nitrate, ammonia, and pathogen analyses should be refri-
gerated under field moist conditions and analyzed as soon as possible.
C.2.4 Soil Analysis
Table C-l lists possible
which may be of interest.
tract the element of interest
soil surface layer and subsurface parameters
Table C-2 lists methods which are used to ex-
______ -.._ __________ -. ______ __- from soil. Table C-3 lists analytical
methods for measuring chemical constituents of interest after extrac-
tion. Table C-4 lists methods, used to analyze soil physical proper-
ties. Table 6-9 in Chapter 6 presents suggested monetary requirements
for sludge applied at agronomic rates for crop production.
C.3 Vegetation
Vegetation monitoring is usually only done if one, or more, of the fol-
lowing situations exist:
1.
2.
3.
Heavy sludge application rates are used, as with a dedicated
disposal site, and there is concern that food chain vegetation
being grown on the site may be accumulating potentially harmful
quantities of heavy metals (particularly Cd) from the sludge
amended soil .
For public relations purposes, it is desirable to assure pri-
vate owners of farms, tree farms, etc., that their crops are
not being adversely affected by their use of sludge.
Research
etc.
purposes, e.g., demonstration projects, test plots,
C-4-
-------
TABLE C-l
POTENTIAL SOIL SURFACE LAYER AND SUBSURFACE
PARAMETERS OF INTEREST
Surface Layer
PH
Electrical conductivity
Lime requirement (acid soils)
Plant available P and K
CEC
Permeability
Particle size distribution
(texture)
C:N ratio (forest lands)
Prior to Sludge Application
Subsurface Layers
PH
Electrical conductivity
Permeability
Particle size distribution
(texture)
Monitoring After Sludge Application
PH
Electrical conductivity
Moisture content
Plant available P and K
NH4-N
Organic-N
Organic matter
Permeability
Particle size distribution
(texture)
Heavy metals (Cu, Ni, Pb, In)
Cd
Persistant organic.s (PCB, DDT,
dieldrin, etc.)
PH
Electrical conductivity
N03-N
NH4-N
* If present in the sludge in significant quantity.
C-5
-------
I
TABLE C-2
EXTRACTION METHODS FOR SOIL
Element Method
Nitrogen (N) Total N: Kjeldahl digestion
method
NH4+ (ammonium): extract
with 2N KC1
N03~ (nitrate) and N0?"
(nitrite): extract
with 2N KC1
Phosphorus Total P: digest in per-
(P) chloric acid
Organic P: extraction with
hydrochloric acid
Available P:
a) Extract with 0.03N NH4F +
0.025N HC1
b) Extract with dilute HC1 +
H2S04
c) Extract with 0.5M NaHC03
d) Extract with water
Sulfur (S) Total S: Johnson and Nishita
digestion method
Organic S:
a) Extract with IN HC1
b) Extract with IN Ca(OAc)2
c) Extract with water
Available S: Use extracting
solution
(39 g NHrfOAc [ammonium acetate]
in 1 1 of 0.25N acetic acid)
Chloride (C1~) Extract with water
Reference
Number
Cation Exchange
Capacity
(CEC)
Exchangeable
Cations
Extract with IN NaOAc
(sodium acetate)
Extract with lN,NH4OAc
(ammonium acetate)
Page
1162
1191
1191
1036
1038
1040
1040
1040
1043
1104
1108
1112
193
899
903
C-6
-------
TABLE C-2 (continued)
Element
Soluble
Salts
Electrical
Conductivity
PH
Carbon (C)
Cobalt (Co)
Selenium (Se)
Method
Water saturation extract
Water saturation extract
1:1 soil/water
Total C: digestion with 60:40
concentrated H2S04/85% HjP04
Organic C:
a) IN K9Cr907 (potassium dichro-
mater '
b) Concentrated H?S04
c) Water
Inorganic C: digestion with con-
Reference
Number
d) IN NH4CT
Extract with solution A (Na^
6N HC1, boiling water) anc
dithizone solution
Digest with nitric acid-
sulfuric acid and
Page*
935
935
920
1350
1374
Boron (B)
Aluminum (Al )
Arsenic (As)
centrated H2S04 and FeS04 7H20
Extract with hot water
Extract with ammonium acetate
(NH4OAc) adjusted to pH 4.8
Extract with:
a) 0.5 N NH4F
b) 0.1 N NaOH
c 0.5 N HoSO*
1
2
2
3
1386
185
185
254
1072
Molybdenum (Mo)
Heavy Metals
(Cu, In, Mn,
Fe, Ni, Pb,
Cr, Hg, Sr,
Cd, Sb, Ag,
Ba)
mercuric oxide (HgO)
Extract with anion exchange
resin (Dowex-l-X4)
Total: extract with strong
acids (HNO,-HC10,,, HNO,-HoS04,
HC1-HNO,)
Available: DTPA;
water, dilute HC1 ,
IN NH4OAc (pH 4.8, pH 7.0)
1
2
1
7
1
1118
17
*
84
t
* Acids selected will depend on, the metal(s) of interest.
t Different extractants have been used for a single metal or a group of
metals. No single extractant is universally applicable to all'metals.
C-7
-------
TABLE C-3. ANALYTICAL METHODS FOR ELEMENTS IN SOLUTION
Measurement
Acidity
Alkalinity
Arsenic (As)
BOO
COD
Chloride
Dissolved
Oxygen
Hardness
MBAS
Metal s :
Calcium (Ca)
Magnesium (Mg)
Zinc (Zn)
Copper (Cu)
Cadmium (Cd)
Mercury (Hg)
Nickel (Ni)
Lead (Pb)
Method
Phenolphthalein
or methyl orange
titration
Potentiometric
titration
Silver diethyl-
dithio-carbamate
method
Dissolved oxygen
determination
Classical reflux
method
Potentiometric
method
Membrane elec-
trode method
EDTA titrametric
method
Methyl ene blue method
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Flameless atomic
absorption
Atomic absorption
Atomic absorption
Std. Method
Number (4)
402
403
404A
507
508
408C
422F
309B
512A
301A
301A
301A
301A
301A
315A
30 1A
301A
Page
273
278
283
543
550
306
450
202
600
144
144
144
144
144
229
144
144
C-8
-------
TABLE C-3 (continued)
Measurement
Chromium (Cr)
Manganese (Mn)
Molybdenum (Mo)
Iron (Fe)
Cobalt (Co)
Aluminum (Al)
Boron (B)
Antimony (Sb)
Nitrogen (N):
N -ammonia
412
N-organic
N-nitrate
N-nitrite
Oil and
Grease
PH
Phenol ics
Phosphorus (P)
Residue:
Filterable
Nonf ilterable
Method
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Colorimetric (Curcumin)
Atomic absorption
Distillation;
nesslerization
Kjeldahl digestion
Electrode method
Colorimetric method
Soxhlet extraction
pH electrode
Distillation; chloro-
form extraction
direct photometric
Digestion; Colori-
metric
Glass fiber filtra-
tion, evaporation
Glass fiber filtration
Std. Method
Number (4)
301A
30 1A
301A
301A
301A
301A
405A
301A
418A, B
421
419B
420
5020
424
510A,B,C
425C,D,E,F
208B.C
2080
Page
144
144
144
144
144
144
287
144
410,
437
422
434
519
460
576
474
92
94
C-9
-------
TABLE C-3 (continued)
Measurement
Total
Volatile
Settleable
Matter
Selenium (Se)
Silica
Specific
Conductance
Sulflde
Turbidity
Method
Evaporation
Ignition method
Imhoff cone method
Diaminobenzidine
method
Gravimetric method
Conductivity mea-
surement
Methyl ene blue or
titrimetric method
Nephelometric method
Std. Method
Number (4)
208A
208E
208F
3 ISA
426A
205
428C,D
214A
Paga
91
95
95
238
485
73
503
132
TABLE C-4. PHYSICAL ANALYSIS FOR SOILS
Parameter
Method
Reference
Number
Partfcle Size
Aneilysis
Permeability:
Soil -to-air
Soil-to-water
Aggregates
(structure)
Hydrometer method/
sieving
Dry sieve method
1
1
1
1
545
524
528
500
C-10
-------
C.3.1 Plant Sampling Procedures
Plant tissue may be sampled during several growth stages, although ma-
ture leaves or stalks growing on main branches or stems are generally
preferred. Table C-5 presents data indicating the portion of various
plants typically sampled, and provides an indication of the number of
separate leaves or stalks necessary for a representative sample. Por-
tions of plants covered by dust or adhering soil, damaged by insects,
mechanically damaged, or diseased should not be sampled.
The basic principles underlying plant tissue sampling are common to both
forestry and agricultural crop species, but specific methodologies
unique to foliar samples of tree species are given below (13):
Sample conifer foliage during the dormant season.
Sample deciduous leaves at maturity.
Sample both dominant and codominant trees.
Sample upper portions of the crown for foliage samples.
Sample current-year foliage.
Do hot sample foliage or twigs bearing cones.
C.3.2 Plant Sample Handling and Preservation
All plant samples should be washed with deionized, distilled water be-
fore drying to remove any surface contamination unless the contaminant
is of analytical concern. In some cases, it may be necessary to wash
the plant samples with a detergent solution or a very weak acid solution
before the final rinse with deionized water.
Samples should be dried (65°C maximum) as quickly as possible, finely
ground, and stored for analysis. If the undried samples cannot be pro-
cessed immediately, they should be placed in polyethylene bags and
stored under refrigeration.
Prior to chemical analysis, the plant tissue sample(s) must be treated
by one of three digestion methods to bring elements into solution. The
methods of digestion depend on the element to be analyzed.
Wet digestion - for all elements except nitrogen (N) and boron
(B). Digest with nitric-perchloric (HN03-HC104) acids.
Treatment with hydrofluoric (HF) acid may be necessary for re-
covery of some of the heavy metals from the silica which pre-
cipitates in the digest.
Dry ashing - ash at low temperature (450° to 500°C). Dissolve
ash in hydrochloric acid (HC1). This is the only method to be
used for B analysis; not suitable for Hg, S, Se, As, Cu, Ag,
Fe, Sb, and N.
Kjeldahl (H2S04) digestion - for total
ence (4), Page 1162, for procedure).
P, and K (see Refer-
C-ll
-------
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Table C-3
tion.
listed the specific analytical methods for elements in solu-
C.3.3 Plant Sample Analysis
It is not common to routinely monitor crops or other vegetation grown on
sludge-to-land application sites. In those cases where plants are moni-
tored, they are generally analyzed for selected heavy metals and/or
plant nutrient content. Table C-6 presents a list of potential monitor-
ing parameters for agricultural crops. Actual parameters monitored may
vary from this list, depending on the sludge constituents of concern.
TABLE C-6. POTENTIAL CROP MONITORING PARAMETERS
A. Heavy Metals
Cadmium
Copper
Molybdenum
Nickel
Zinc
C. Other Elements or Constituents*
Antimony
Arsenic
Chromium
Iron
Manganese
Mercury
Selenium
PCB's
B. Macronutrients (Optional)
Nitrogen
Phosphorus
Potassium
* The other elements or constituents listed under C are analyzed only
if there are significant quantities of those contained in the sludge
being applied, and the crop may enter the food chain.
C.4 Ground Water Monitoring
Ground water monitoring may be required to ensure that the project is
not contaminating useful ground water aquifers in the sludge application
site or sludge storage area. Regulatory agencies often require ground
water monitoring for dedicated sludge disposal sites, and may also occa-
sionally require ground water monitoring for forest land or disturbed
land sludge utilization over sensitive aquifers. Rarely is ground water
monitoring required for projects using the agricultural utilization
option, since by definition this option balances sludge application
rates with crop nutrient requirements.
C-13
-------
C.4.1 Ground Water Monitoring Design
If a ground water monitoring program is required, a hydrogeologist
should be consulted during the initiation and implementation of the pro-
gram. Detailed ground water monitoring procedures can be found in the
U.S. EPA publication (EPA/530/SW-611) entitled, Procedures Manual for
Ground Water Monitoring at Solid Waste Disposal Facilities (14).
Monitoring wells are constructed to provide representative ground water
samples. The number of wells needed and their proper placement depends
on the location of the water table and the direction of ground water
flow. If several aquifers could be affected, a set of monitoring wells
is required for each aquifer. The depth of the monitoring wells is de-
pendent on the depth of the aquifer(s) being sampled, and the predicted
pathway of potential migrating contaminants. A qualified hydrologist
should be involved in making these decisions, based on specific geologic
and hydrologic conditions at the site. Consideration should be given to
such factors as the following (9):
t Soil and rock formations existing on the site.
Direction
ment.
of ground water flow and anticipated rate of move-
Depth of seasonal high water table, and an indication of sea-
sonal variations in ground water depth and direction of move-
ment. This should not be a problem with dewatered sludge or
liquid sludge at agronomic rates.
Nature, extent, and consequences of ground water mounding,
which may occur above the naturally occurring water table.
t Depth of impervious layers.
It may be necessary to establish baseline site ground water conditions
through installation of simple observation wells prior to the actual
selection of locations and depths for permanent monitoring.
Generally, if monitoring is required, three or more monitoring wells are
installed, as follows:
One background well located upstream, and not affected or con-
taminated by sludge application.
One or more (depending on site size and hydrogeological fac-
tors) wells located off-site downgradient from the site, and
used to detect leachate migration.
One or more on-site wells located in the zone of maximum
leachate concentration.
C-14
-------
Often, monitoring wells are installed during the site selection and/or
design investigations. It is desirable to start monitoring 6 months to
a year before any sludge applications to establish background ground
water quality including any seasonal fluctuations.
Figure C-l shows a typical monitoring well. Important features include
an impermeable backfill, PVC piping, well screen, and gravel fill
around
ground
should
chemi-
the well screen. The composition of the materials selected for
water monitoring well construction, sample collection and storage
be examined for possible contamination and interference with the
cal analysis. For example, galvanized pipe should not be used when
testing for trace metals. Inert materials such as ABS or PVC reduce the
possibility of erroneous readings, although the glues used on the fit-
tings can also contaminate samples. Disinfection of wells, equipment,
and containers by chlorination or other means is required if bacteriolo-
gical examination is included (8). However, no residual chlorine must
remain after disinfection or microbial counts will be reduced.
A dry drilling method (e.g., augering) is preferred for the construction
of monitoring well boreholes, since it eliminates contamination of
ground water with drilling mud and offers lower installation costs.
Coring, with hollow- or solid-stem augers, and hydraulic rotary drilling
are the most common dry and wet drilling methods, respectively.
The boreholes are normally backfilled by packing with gravel and sand
around the screened area of the pipe. A low-permeability material, usu-
ally bentonite or a sand-bentonite mixture, is then packed to prevent
surface water from channeling down the side of the casing. A concrete
support is built around the above-ground portion of the well to protect
it from damage or vandalism.
C.4.2 Ground Water Sampling Collection Methods and Frequency
Ground water sampling can be collected using a bail, air lift, submersi-
ble pump, or vacuum, depending on the analyses to be performed. For
example, when sampling of ground water for reduced species (e.g., H2S)
the possibility of air contamination or C^ injection into the sampling
system. To the extent possible, collection techniques should remain
consistent throughout the monitoring program.
Recommended
(10):
precautionary procedures at the wells include the following
A measured amount of water equal to or greater than three
times the amount of water in the well and/or gravel pack
should be exhausted from the well before sample collection.
In the case of very low-permeability soils, the well may have
to be exhausted and allowed to refill before a sample is col-
lected.
C-15
-------
LAND SURFACE
SLOPED AWAY
FROU WELL
BOREHOLE
SCHEDULE 40 PVC
CASINO
SLOTTED SCHEDULE
4O PVC SCREEN
LOW PERMEABILITY
BACKFILL
GRAVEL PACK
WATER TABLE
Figure C-l. Typical monitoring well screened over
a single vertical interval.
C-16
-------
9 Pumping equipment should be thoroughly rinsed before use in
each monitoring well. Water pumped from each monitoring well
should be discharged to the ground surface away from the wells
to avoid recycling of flow in high-permeability soil areas.
Samples should be collected, stored, and transported to the
laboratory in a manner to avoid contamination or interference
with subsequent analyses.
The frequency of sample collection is dependent upon the goals of a par-
ticular ground water monitoring (i.e., whether it is long- or short-
term). The estimated rate of pollutant travel in a given hydrogeologic
setting will indicate intervals of time which will show a change in
water quality. Careful analyses of the initial and later samplings may
warrant adjustment of the sampling frequency. Arbitrary selection of
sampling frequency may not reveal the true picture of ground water qual-
ity at the disposal site.
C.4.3 Ground Water Sample Preservation
It is impossible to maintain complete stability for every constituent in
a water sample. Preservation techniques can only retard the chemical
and biological changes that inevitably continue after the sample is col-
lected. Table C-7 presents methods of preservation for water samples,
volume required, container type, and storage time, as recommended by the
U.S. EPA (6). Refrigeration at temperatures near freezing (2 to 4°C) is
the best available preservation technique. Water pH should be deter-
mined on site, while other analyses should be made as soon as practical
in the laboratory.
C.4.4 Ground Water Parameters
The constituents included in the .analysis of ground water samples are
dependent on such factors as monitoring goals, budgetary restrictions,
waste composition, uses of ground water, regulatory requirements, etc.
If the ground water involved is an actual or potential potable water
supply parameters for which drinking water standards have been estab-
lished should be measured (11, 12). If high concentrations of certain
heavy metals, toxic chemicals, or fecal bacteria are present in the
sludge, they should be included in the ground water monitoring list. No
single list of parameters applies to all cases.
As an illustration of parameters which are often analyzed in ground
water samples taken in connection with sludge application site(s) moni-
toring, the following list is presented:
PH.
Electrical conductivity and/or TDS.
Total hardness.
Alkalinity.
Chlorides.
C-17
-------
TABLE C-7
SAMPLE SIZE AND SAMPLE PRESERVATION3 (6)
Measurement
Acidity
Alkalinity
Arsenic
BOO
Bromide
LOU
Chloride
Chlorine Req.
Color
Cyanides
Dissolved
Oxygen
Probe
Uinkler
Fluoride
Hardness
Iodine
H8AS
Hetjli
Dissolved
SUM-MI.).*!
luUI
Mercury
Dissolved
Total
Nitrogen
Atnnonia
Kjeldahl
Hitrate
Nitrite
NTA
Oil & Grease
Organic Carbon
pH
Phenol ics
Vol.
reg.
(ml)
100
100
100
1,000
100
'jO
50
50
50
500
300
300
300
100
100
250
200
IUU
100
100
400
500
100
50
50
1.000
25
2S
500
Container
P,Gb
P,G
P.G
P.G
P.G
I'.C
p. a
P,G
P.G
P.G
G only
G only
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P,G
P.G
G only
P.G
P.G
G only
Preservation
Cool , 4*C
Cool. 4°C
HN03 to pH < 2
Cool , 4°C
Cool. 4°C
H2i04 to P" < 2
None Req.
Cool, 4eC
Cool, 4°C
Cool , 4°C
NaOH to pH 12
Det. on site
Fix. on site
Cool. 4'C
Cool . 4°C
Cool, 4"C
Cool , 4°C
Filter on site
HNOj to pH < 2
filter on s(l.»
IINU3 La pll < 2
Filter
HN03 to pH < 2
HN03 to pH < 2
Cool . 4°C
H2S04 to pH < 2
Cool , 4°C
IbSOn to pll < 2
Cool . 4"C
H2SCool° SV Z
Cool , 4°C
Cool . 4°C
H2S04 to pH < 2
Cool , 4°C
HzS04 to pH < 2
Cool . 4°C
Det. on site
Cool . 4°C
HiPOa to pH < 4
1.0 g CuS04/l-
Standard
Holding Method
tinic1* Number^
24 hrs
24 hrs
6 mos
6 hrsc
24 hrs
/ days
7 days
24 hrs
24 hrs
24 hrs
None
None
7 days
7 days
24 hrs
24 hrs
6 months
6 months
38 days
(glass)
13 days
(hard
plastic)
38 days
(glass)
13 days
(hard
plastic)
24 hrsd
24 hrsd
24 hrsd
24 hrsd
24 hrs
24 hrs
24 hrs
6hrsc.
24 hrs
402
403
404
507
406
!>UU
400
4)2
204
413
402
414
309
416
512
301
315
417
418
421
419
420
--
502
505
424
574
C-18
-------
TABLE C-7 (continued)
Measurement
I'liuiphurui
Ortho-
phosphate,
dissolved
Hydrolyzable
Total
Iota),
dissolved
Residue
Filterable
Non-filterable
Total
Volatile
Settleable
matter 1
Selenium
Silica
Specific
conductance
Sul fate
Sulfido
Sulfite
Temperature 1
Threshold
odor
Turbidity
Vol.
rey.
(ml)
50
50
50
50
100
100
100
100
,000
50
50
100
50
50
50
,000
200
100
Container
P,G
P.G
P.G
P.G
' P.G
P,G
P.G
P,G
P,G
P.G
P only
P.G
P.G
P.G
P.G
P.G
G only
P.G
Preservation
Filter on site
Cool, 4°C
Cool , 4°C
H2S04 to pH < 2
Cool , 4°C
Filter on site
Cool, 4°C
Cool , 4°C
Cool, 4°C
Cool . 4°C
Cool , 4°C
None Req.
IIN03 to pH < 2
Cool, 4°C
Cool . 4°C
Cool, 4"C
t ml zinc
acetate
Cool, 4°C
Get. on site
Cool , 4°C
Cool. 4°C
Holding
tte*
24 hrsd
24 hrsd
24 hrsd
24 hrsd
7 days
7 days
7 days
7 days
24 hrs
6 months
7 days
24 hrse
7 days
24 hrs
24 hrs
None
24 hrs
7 days
StjtuUrd
Method
Number'^
4E5
208
208
318
426
205
427
428
429
212
206
214
a More specific instructions for iirusorvatlon and b-imiil Iny oru found with
cjcn procedure as detailed in the literature (25).
b Plastic or ylass
c If samples cannot be returned to the laboratory in less than 6 hrs and
holding lime exceeds this limit, the final reported data should indi-
cate the actual holding time.
d Mercuric chloride may be used as an alternate preservation at a concen-
tration of 41} iwj/1, especially if a longer holding time is required.
However, the use of mercuris chloride is discouraged whenever pos-
sible.
c If thu sample is stabili/od by,cool ing, it should be wanned to 25°C for
reading or temperature correction made and results reported at 25°C.
f It has been shown that samples properly preserved may be held for
extended periods beyond the recommended holding time.
9 The numbers in this column refer to the appropriate parts of the
"standard Methods for the Examination of Water and Wastewater, 14th
edition, APHA-AHWA-WPCF, 1975.
C-19
-------
Sulfates.
Total organic carbon.
Ni trate-ni trogen.
Total phosphorus.
Methylene blue active substances (surfactants).
Selected metals or toxic substances, where applicable.
Indicator microorganisms.
Regulatory agencies may require fewer or more parameters than listed
above, depending on the sensitivity of the aquifer being sampled and
other factors.
C.4.5 Ground Water Monitoring in the Unsaturated Zone
The unsaturated soil zone is the soil located vertically between ground
surface and the top of the water table. Collection devices installed in
the unsaturated zone will collect samples of the leachate migrating down
from the sludge amended surface soil to the ground water aquifer, and
can provide early warning of potential future ground water contamina-
tion. Unsaturated zone monitoring is rarely required or used. Possible
uses are for research and demonstration projects or occasionally for
dedicated land disposal sites. The most commonly used devices to col-
lect leachate are pressure-vacuum lysimeters. They are relatively in-
expensive and fairly reliable. A typical pressure-vacuum lysimeter is
shown in Figure C-2. In an optimum arrangement, lysimeters are in-
stalled at various depths in the unsaturated zone. Bentonite plugs are
placed at the top and bottom of each hole during backfilling to prevent
channeling of contaminated surface water directly to the lysimeter.
Alternatively, the lysimeters can be installed horizontally into the
soil or at angles along the edge of the site. There is some indication
in literature that horizontal placement is better than vertical place-
ment. The porous ceramic cup in each lysimeter should be surrounded by
a slurry of wet, fine quartz which ensures hydraulic continuity with the
surrounding soil.
After the lysimeters are in place, a vacuum is applied to the system and
the tubes are clamped off. To collect leachate samples, the vacuum is
released and the discharge tube is placed in a sample container. Air
pressure is applied to the other tube which forces the leachate up the
tube and into the sample container.
The degree to which the porous cup selectively filters various elements
may pose a potential problem for collecting representative samples.
Preliminary testing should be conducted to evaluate whether the parame-
ter of concern is filtered out by the porous cup.
C.5 Surface Waters
Properly designed sludge-to-land application sites are generally
located, constructed, and operated to minimize the chance of surface
water runoff containing sludge constituents. For sites utilizing the
C-20
-------
Screened
Backfill
Bentonits
-Screened Backfill
Bentonite
Access Tube
(Pressure/Vacuum)
Access Tube
(Discharge)
Clamp Ring
Nepprsne
Plug
Body Tube
Porous Ceramic Cup
Figure C-2
Typical pressure/vacuum lysimeter
for leachate monitoring.
C-21
-------
agricultural utilization option at agronomic rates of sludge applica-
tion, surface water monitoring is rarely required. Generally, surface
water monitoring is done only in one, or more, of the following situa-
H one
tions:
Surface water runoff from the site is collected, stored, and
discharged to surface waters outside the application area
under an NPDES permit.
The sludge application site is in close proximity to surface
>rs which are sensitive (e.g., drinking water supplies,
waters which are sensitive (e.g., drinking water supplies,
swimming areas,etc.), and monitoring is required by the cogni-
zant regulatory agency to ensure that migration of sludge con-
stituents to these surface waters is not occuring.
t It is desirable for public acceptance purposes to moderate
community concern about surface water quality impacts.
C.5.1 Surface Water Monitoring Procedures
Selection of surface water sampling stations, equipment, and procedures
should follow a systematic plan. Surface sampling stations should be
located in areas which represent .the greatest potential for contamina-
tion. These points can be determined after examining the pathways
available for runoff to enter a surface water body. Flow patterns and
seasonal variations should be noted when applicable.
C.5.1.1 Rivers and Streams
Sampling stations should be established at stream sections where the
water composition is relatively uniform. Such sections can be located
on small- and medium-size streams, but are frequently impossible to find
on large rivers. Where uniform sections can be found, sampling proce-
dures may often be simplified to the extent that a single grab sample
may be obtained that is representative of the stream composition in that
general location.
C.5.1.2 Lakes and Reservoirs
A thorough study of water composition can be made by sampling along a
three-dimensional grid pattern; samples can be collected at different
depths at each grid intersection. A more economical approach is to sam-
ple a different depth along selected cross sections and sampling points.
When only one sample is collected to define the average character of the
lake or reservoir, it should be collected near the center of the water
mass. However, a single sample is completely inadequate for a study of
a lake of any size, and at best provides only an approximation of aver-
age water quality. To evaluate the quality of reservoir water for po-
tential downstream users, the sampling site should be located at or near
the point of discharge.
C-22
-------
Surface water sampling equipment should be suited to the goals of a par-
ticular monitoring program. Sampling equipment and procedures can range
from continuous or intermediate automated samplers to manual collection
by filling a container by hand. Manual sampling is generally considered
to be adequate.
C.5.2 Surface Water Sample Preparation
See Table C-7.
C.5.3 Surface Water Parameters
Generally, the parameters of concern in a surface water monitoring pro-
gram are those which either may affect public health, or those which may
contribute to eutrophication, e.g., nitrogen and phosphorus. An illus-
tration of parameters which are often analyzed in surface water samples
taken in connection with sludge application site(s) monitoring is shown
in the following list:
Fecal coliforms.
Total-P.
Total N (Kjeldahl).
Dissolved oxygen.
BOD or TOC.
Temperature.
pH.
Suspended solids.
C.6 Sludge
Virtually all POTW's which intend to apply sludge to land under one of
the sludge utilization options covered by this manual will be required
to routinely sample and analyze the sludge being applied. Among the
many purposes for sludge monitoring are:
0 To obtain baseline data on sludge physical and chemical char-
acteristics prior to design of the sludge to land utilization
system (see Chapter 3). This data is necessary to design vir-
tually every component of the system, e.g., sludge transport,
application site size, sludge application rates, etc.
a To provide records of the quantity of sludge constituents,
e.g., nutrients, metals, etc., being applied to the sludge ap-
plication site(s).
To verify adequate sludge
POTW.
stabilization operations at the
To satisfy regulatory agency requirements.
C-23
-------
C.6.1 Sludge Sampling Frequency
The frequency of sludge sampling necessary will usually be set by the
regulatory agency, and may vary from daily samples for a very large sys-
tem to quarterly samples for a very small system. See Section 11.5.2
for a general discussion of factors involved in determining sludge sam-
pling frequency.
Since concentrations of many constituents in sewage sludge from the same
POTW vary significantly over time (see Appendix A), a single sample is
generally not representative of sludge quality over time. Multiple sam-
ples should be taken to assure statistically valid estimates of sludge
constituent concentrations. A typical simplified procedure is outlined
below.
t Step 1: Take weekly composite samples for five consecutive
weeks and analyze the constituents of concern (e.g., percent
solids, nutrients, heavy metals, etc.) for each of the five
samples.
Step 2: Calculate the average concentration for each constit-
uent by summing the sample concentrations and dividing by
five.
Step 3: Calculate the statistical variances to determine if
there is a 95 percent probability that the average determined
in Step 2 is within ±25 percent of the "actual" average.
"Standard Methods for Examination of Water and Wastewater" (4)
contains a section on precision and accuracy which details de-
termination of 5 percent probability. The formula below can
be used:
Variance = (0.25 x (x-y)
Where: x = the sum of the squares of the five weekly
concentrations; and y-.= one-fifth the square of the sum
five weekly sample concentrations.
sample
of the
Step 4: Multiple 123.3 times the variance and divide the re-
sult by the square of the average calculated in Step 2. This
provides a "testing number." If the "testing number" is below
5..00, then the average concentration calculated in Step 2 has
statistically 95 percent probability.
If the "testing number" is above 5.0, additional weekly com-
posite sludge samples should be taken until an average concen-
tration with 95 percent probability is obtained.
C-24
-------
C.6.2 Sludge Sampling Location
The sludge samples should be representative of the sludge being applied
to the application site (5). If sludge is being hauled directly from
the POTW, and applied without intervening storage, sample may be compo-
sited at the' POTW. However, if sludge is stored at. an intermediate
facility prior to field application, the sludge samples should be com-
posited after withdrawal from the storage facility. Many sludge con-
stituents .usually increase, but ammonia nitrogen concentration de-
creases. Obviously, the best. location for sludge sampling is at the
sludge application site itself during application operations.
C.6^3 Sludge Sample Preservation
Sludge samples should be refrigerated at approximately 4°C immediately
after collection, which provides adequate preservation for most types of
sludge physical and chemical analyses for a period of up to 7 days,
i.e., sufficient to obtain a weekly composite sample. Analysis for bac-
teria, parasite, etc.,
24 hours. If this is
should be made as soon as possible, e.g., within
not possible, the samples may be frozen.
C.6.4. Sludge Parameters
The common analyses for sludge are as follows:
Percent solids.
Percent volatile solids.
Ammonia nitrogen*
Total-nitrogen.
Heavy metals (Zn, Ni, Cu, Pb, and Cd).
Total phosphorous.
Other analyses may be performed routinely because of. a specific sludge
characteristic known to be significant or because of regulatory require-
ments. These may include:
Chromium'.
Mercury.
Arsenic.
Various' pesticides and other persistent organics.
Phenols.
Biological.
Table C-8 lists standard extraction methods for certain sludge elements.
When the element is in solution, see Table.C-3 for analytical methods.
C.7 References '
1. Black, C. A., ed. Methods of Soil Analysis.
Agronomy, Madison, Wisconsin, 1965. 1572 pp.
American Society of
C-25
-------
TABLE C-8
EXTRACTION METHODS FOR SLUDGES
El ement
Nitrogen (N):
Total N
N-ammoni a
N-nltrate
N-nitrite
Phosphorus (P):
Total P
Organic P
Inorganic P
Carbon (C)
Organic C
Reference
Method Number
Kjeldahl digestion
Extract with 2N KC1
Extract with 2N KC1
Extract with 2N KC1
Persulfate digestion
Persulfate digestion
Total P minus organic P
a) IN K?Cr?0,
u \ _-.=_ 4.±r-..& ,,»j u en
i
i
i
i
4
4
-
1
Page
1164
1191
1191
1191
474
474-
-
1374
Total C
Inorganic C
Metals
c) water
Digestion with 60:40
concentrated
H2S04/85% H3P04
Digestion with concen-
trated HoSOd
and FeS04 . 7H20
Digest with HNO, +
HC104
1350
1386
144
C-26
-------
2. Walsh, L. M., and J. D. Beaton, eds. Soil Testing and Plant Analy-
sis. Soil Science Society of America, Madison, Wisconsin, 1973.
3. Woolson, E. A., 0. H. Azley, and P. C. Kearney. The Chemistry and
Phytoxicity of Arsenic in Soils. Soil Science Society of America,
1973. pp. 254-259.
4. Standard Methods for the Examination of Water and Wastewater. 14th
Edition. American Public Health Association, Washington, D.C.,
1976. 1193 pp.
5. Ellis, R. Sampling and Analysis of Soils, Plants, Wastewaters, and
Sludge: Suggested Standardization and Methodology. North Central
Regional Publication 230, Agricultural Experiment Station, Kansas
State University, Manhattan, December 1975. 20 pp.
6. Methods for Chemical Analysis of Water and Wastes. EPA-625/6-74-
003a, U.S. Environmental Protection Agency, Cincinnati, Ohio, July
1976.
7. Lindsay, W. L., and W. A. Norvell. Development of a DTPA Soil Test
for Zinc, Iron, Manganese, and Copper. J., 42:421-428, 1978.
8. Walsh, J. Process Design Manual for Municipal Sludge Landfills.
EPA-625/1-78-010, SCS Engineers, Reston, Virginia, October 1978.
331 pp.
9. Blakeslee, P. A. Site Monitoring Considerations. In: Application
of Sludges and Wastewaters on Agricultural Land: A Planning and
Educational Guide, B. D. Knezek and R. H. Miller, eds. Ohio Agri-
cultural Research and Development Center, Wooster, 1976. pp. 11.1-
J. J. 0 o
10. Loehr, R. C., W. J. Jewell, J. D. Novak, W. W. Clarkson, and G. S.
Friedman. Land Application of Wastes, Volume 2.
Reinhold, New York, 1979. 431 pp.
Van Nostrand
11. Environmental Protection Agency National Primary Drinking Water
Regulations. 40 CFR 141.
12. Environmental Protection Agency National Secondary Drinking Water
Regulations. 40 CFR 143.
13. Edmonds, R. L., and D. W. Cole. Use of Dewatered Sludge as an
Amendment for Forest Growth. College of Forest Resources, Univer-
sity of Washington, Seattle, August 1977.
14. Fenn, D. G. Procedures Manual for Ground Water Monitoring at Solid
Waste Disposal Facilities. EPA/30/SW-611, Wehran Engineering,
Mahwah, New Jersey, August 1977. 283 pp.
C-27
-------
-------
APPENDIX D
CASE STUDY OF SLUDGE USE FOR RECLAMATION
OF DISTURBED MINING LANDS IN VENANGO COUNTY, PENNSYLVANIA
The Venango County, Pennsylvania, demonstration project provides an
example of a well-planned and managed reclamation project that used
sludges from local small cities to reclaim a bituminous coal strip mine
spoil bank that had been recontoured without topsoil replacement. The
post-mining land utilization of the site was vegetation establishment to
reduce soil erosion and sedimentation followed by natural succession
leading to a mixed hardwood forest cover.
D.I Site Location
The site was mined by a coal company in 1965, and is located in Irwin
Township, Venango County, Pennsylvania. It was mined prior to the pas-
sage of the current surface mining regulations (PL 95-87) that require
topsoil replacement. Three previous attempts were made by the coal com-
pany to reclaim the area using lime, commercial fertilizer, and seed;
however, these efforts were unsuccessful and the site was essentially
barren. Four ha (10 ac) of the approximate 40 ha (100 ac) area was se-
lected for sludge application in a demonstration project. To maximize
the value of the project, both liquid and dewatered sludges at a high
and low rate were applied. After completion of the demonstration proj-
ect, it is planned to continue to use sludge to complete reclaiming the
remaining 36 ha (90 ac).
D.2 Preliminary Preparations
D.2.1 Pretreatment Soil Sampling
Twenty-one soil pits were excavated on the demonstration site with a
backhoe to a depth of 90 cm (36 in). Each pit was used for the collec-
tion of soil samples and for the installation of suction lysimeters for
percolate water sample collection. Three soil pits were excavated in
each sludge treatment sub-plot and in an adjacent control. Soil samples
were collected at the 0 to 15 (0 to 6 in) 15 to 30 (6 to 12 in), 30 to
60 (12 to 24 in), and 60 to 90 cm (24 to 36 in) depth for chemical anal-
yses. For a site not being used as a demonstration, only 3 to 4 soil
pits would be needed for monitoring purposes. Surface soil samples were
collected from the area for initial soil pH to determine liming require-
ments, and the cation exchange capacity of the area.
D.2.2 Monitoring Instrumentation
A monitoring system was established as required in Pennsylvania, to de-
termine the effects of the sludge applications on chemical and bacterio-
logical quality of ground water and soil percolate, on the chemical
properties of the soil, and on the vegetation.
D-l
-------
Two suction lysimeters were installed in the excavated soil pits at the
90 cm (35 in) depth for the collection of percolate water samples. One
was used specifically for the collection of percolate water for bacte-
rial analyses (total and fecal coliform) and the other for routine chem-
ical water quality analyses. Samples were collected bi-weekly for the
first five months and then monthly thereafter. For non-demonstration,
large-scale projects in Pennsylvania, only monthly sampling is required.
Three 15 cm (6 in) diameter ground water wells were drilled to monitor
the effects of the sludge application on ground water quality. Ground
water well sites were located by geologists of the Pennsylvania Depart-
ment of Environmental Resources to collect samples upgradient and down-
gradient of the sludge application site. The depth of each well and the
depth to the water level at the time of drilling was as follows:
Well No.
1 (upgradient)
2 (downgradient)
3 (downgradient)
Metric conversion factor:
1 m = 3.281 ft.
18.0
17.8
11.4
Depth to
Water Level
(m)
5.3
3.3
2.1
Ground water well samples were collected on the same schedule as perco-
late water samples. Samples were collected with both a submersible pump
and a Kemmerer water sampler. The pump was used to remove standing
water and draw-down the well. After recovery, the pump was used to ob-
tain a sample of fresh water in the well. For nondemonstration projects
in Pennsylvania, only one downgradient ground water monitoring well is
required.
Water samples were also collected from two
stration plots. The samples were analyzed
the soil percolate water samples.
lakes adjacent to the demon-
for the same constituents as
D.2.3 Background Sludge Sampling
Sludge for the demonstration project was obtained from POTW's at the
cities of Parrel!, Franklin, and Oil City, Pennsylvania. Liquid sludge
was obtained from Farrell and Oil City, and dewatered sludge from Frank-
lin and Oil City. Sludge samples were collected from each plant and an-
alyzed to determine the loading rates and acceptability of the sludges
for land application. Analysis of the sludge constituents as they were
applied to the site are presented in Tables D-l and D-2.
D-2
-------
TABLE D-l
CHEMICAL ANALYSIS OF DEWATERED SLUDGE APPLIED
ON THE VENANGO COUNTY DEMONSTRATION PLOTS
Constituent
PH
Total P
No3-N
NH4-N
Organic N
Total N
Ca
Mg
Na
K
AT
Mn
Fe
Co
Zn
Cu
Pb
Cr
Ni
Cd
Hg
PCB
Mean
7.9
4,624
46
727
12,188
12,962
9,970
2,082
286
93
6,133
1,651
29,709
22
811
661
349
413
69
3.2
0.6
1.2
Range
High
8.2
nnm nn Hr*v wo "inhi* K^cic
p pill Ul i Ul Jr WC I y 1 1 U U Q o 1 o
6,327
52
839
14,612
15,500
12,699
3,108
350
142
8,641
2,703
44,561
34
1,008
967
377
665
111
4.1
0.9
1.4
Low
7.7
2,701
40
635
9,990
10,768
3,805
590
235
44
1,208
285
5,912
13
295
471
302
180
55
1.2
0.4
1.0
D-3
-------
TABLE D-2
CHEMICAL ANALYSIS OF LIQUID DIGESTED SLUDGE APPLIED
ON THE VENANGO COUNTY DEMONSTRATION PLOTS
Constituent
pH
Total P
No3-N
NH4-N
Organic N
Total N
Ca
Mg
Na
K
Al
Mn
Fe
Co
Zn
Cu
Pb
Cr
Ni
Cd
Hg
PCB
Mean
6.8
5,883
1,780
4,217
20,509
26,506
39,726
6,689
6,264
407
19,545
808
28,517
21
1,796
1,750
999
1,560
113
8.8
0.9
1.5
Range
High
7.0,
Dorn on drv weidht basis
iJLflll \j 1 1 Mljr » t , lyiii* u \A~J t *j
7,293
3,869
6,295
25,021
35,185
63,836
12,051
8,734
542
42,083
1,022
34,460
25
2,138
2,481
1,201
2,521
129
14.1
1.6
2.7
Low
6.6
4,819
528
2,633
18,010
21,750
26,344
4,707
3,935
304
6,667
531
20,909
19
1,031
793
741
409
95
5.7
0.4
0.1
D-4
-------
D.3 Site Preparation
Four 1-ha (2.5-ac) plots
tion. Two of these-plots
dewatered sludge.
D.3.1 Scarification
were laid out and marked for sludge applica-
received liquid digested sludge, the other two
Prior to application, a portion of the demonstration area was scarified
with a tractor and chisel plow. This was necessary because the surface
spoil material had been compacted in the backfilling and leveling opera-
tion. In addition, the roughened surface would prevent runoff of sludge
should an unusually heavy rainfall occur during the sludge application
operation. The area to receive the dewatered sludge was completely
scarified. However, the chisel plow dug up many large rocks and brought
them to the surface. As a result, it was decided to scarify only the
perimeter of the plots to receive liquid digested sludge, as a precau-
tion against sludge runoff.
D.3.2 Liming
Analyses of surface soil samples indicated that the average soil pH was
3.9 (buffer pH 5.9) in the area to receive dewatered sludge. Therefore,
agricultural lime was applied at the rate of 12.3 mt/ha (5.5 T/ac).
This amount of lime was sufficient to raise the soil pH to 6.5. Liming
is a Pennsylvania regulatory requirement and is necessary to immobilize
the heavy metal constituents in the sludge and prevent them from leach-
ing into the ground water.
Lime was also applied to one plot (1.0 ha; 2.5 ac) to receive liquid di-
gested sludge. Average soil pH was 6.1 (buffer pH was 6.6). Lime was
applied at the rate of 4.5 mt/ha.
D.3.3 Diversions and Berms
Diversion ditches were installed to prevent sludge runoff in the direc-
tion of the two lakes on the property. A berm was constructed on three
sides of the dewatered sludge unloading and storage area to prevent any
movement of sludge from the area and to prevent water running into the
sludge unloading area from higher ground.
D.4 Sludge Application and Incorporation
Because of the diversity of waste treatment processes and the variation
in concentration of constituents in the sludges, it was decided to mix
the sludges on the site prior to application. Samples of the sludge
mixture were collected as the sludge was applied on the demonstration
plots. Six composite samples were collected as the dewatered sludge was
applied and five composite samples were collected as the liquid sludge
was applied. The results of these analyses are given in Table D-l (de-
watered sludge) and Table D-2 (liquid digested sludge). Average solids
D-5
-------
content for the liquid digested sludge was 3 percent and for the dewa-
tered sludge was 52 percent. Average total nitrogen content was 1.3
percent for the dewatered sludge and 2.7 percent for the liquid digested
sludge.
Results of the sludge analyses were used to calculate the amounts of se-
lected nutrients and trace elements applied in the various application
rates. These amounts are given in Table D-3.
A comparison of the maximum sludge application rate"with the EPA and
PDER recommendations is given in Table D-4. The amounts of trace metals
applied in the sludge were below the PDER recommendations with the ex-
ception of copper. The amount of copper applied slightly exceeded the
POER recommendation but was well below the EPA recommendation.
The commercial fertilizer equivalents of the various sludge application
rates are given in Table D-5. The highest sludge application rate would
be equivalent to applying 10 mt/ha (4.5 T/ac) of an 11-9-0 commercial
fertilizer. The value of the sludge as a commercial fertilizer substi-
tute is quite obvious.
D.4.1 Liquid Digested Sludge
During May 17-23, 1977, liquid digested sludge was hauled in tank trucks
(19,000 to 26,000 1; 5,020 to 6,869 gal) from the cities of Farrell and
Oil City. At the site the liquid sl'udge was emptied from the tankers
into a temporary small holding pond with a plastic liner. The pond pro-
vided a means for mixing the two sludges. A vacuum tank liquid manure
spreader with a 5,700 1 (1,506 gal) capacity pumped the sludge from the
holding pond and spread it on the plots (Figure D-l). One-half of the
demonstration area received liquid sludge at an application rate of 155
nr/ha (equivalent to 11 dry mt/ha; 4.9 T/ac). The other half received
sludge at the rate of 103 m /ha (equivalent to 7 dry mt/ha; 3.1 T/ac).
It was not possible to apply the liquid digested sludge at the proposed
design rate of 20 mt/ha because infiltration was restricted, and no more
sludge could be applied without the threat of producing surface runoff.
D.4.2 Dewatered Sludge
During May 18-21, 1977, dewatered sludge was transported by coal trucks
from the cities of Franklin and Oil City. A total of 588 wet mt (647 T)
of sludge was transported to the site. The sludge from the two treat-
ment plants was unloaded at the site and mixed with a front-end loader
prior to application with a farm manure spreader (Figure D-2). One-half
of the demonstration site (1.0 ha; 2.5 ac) received an application of
dewatered sludge at the rate of 90 mt/ha (40.0 T/ac) and the other half
(1.0 ha; 2.5 ac) received 184 mt/ha (82.1 T/ac). Sludge spreading was
completed by May 25, 1977. On May 26, 1977, a tractor with a 6.4-mt
(7.04 T) disc attachment was used to incorporate the .sludge into the
surface 10 cm (4 in) of spoil material (Figure D-3).
D-6
-------
TABLE D-3
AMOUNTS OF SELECTED NUTRIENTS AND TRACE
ELEMENTS APPLIED BY EACH SLUDGE APPLICATION ON THE
' VENANGO COUNTY DEMONSTRATION PLOTS
Sludge Application Rate in Metric Tons/Hectare
Constituent 184 90 11 ]_
---___ kg/ha -
Total N.
P :
K
Cu
Zn
Cr,
Pb . -. .
Ni
Co
Cd
Hg
2,388
918
' 18
129
147
74 .
55 .
12
3
0.6
0.09
1,165
448
9
63
72
36
27
7
2
0.2
0.04
284
63
4
21
21
16
10
1
0.2
0.09
0.01
187
41
2
13
13
10 ,
7
0.7
0.1
0.07
0.007
Metric conversion factors:
1 kg/ha .= 0.89 Ib/ac.
! rat/ha = 0.446 T/ac.
TABLE D-4
COMPARISON OF TRACE METAL LOADINGS AT THE
VENANGO COUNTY DEMONSTRATION PROJECT WITH
EPA AND PDER RECOMMENDATIONS (13)
Constituent
Cu
Zn
Cd
Pb
Ni
. 'Cr
Hg
Sludge
Application
Rate
184 rat/ha
,
129
147
0.6
55
12
'74
0.09
Recommendations
EPA .
(CEC 5-15)
- - kn/ha _______
250
500
IP
1,000
250
NRf
NR1"
PDER
112
224
, 3
112
22'
112
0.6
* Average CEC of site ranged from 11.6 to 15.2 meq/lOOg.
t No recommendations given by EPA.
Metric conversion factors:
1 mt/ha
1 kg/ha
0.446 T/ac
0.89 Ib/ac.
D-7
-------
TABLE D-5
COMMERCIAL FERTILIZER EQUIVALENTS OF THE
SLUDGE APPLICATION RATES IN VENANGO COUNTY
SI udge
Application
Rate
mt/ha .
184
90
11
7
Fertil
Amount
kg/ha
22,400
11,200
2,240
2,240
izer Equivalent
N
kg/ha (%)
2,388 (11)
1,165 (10)
284 (13) '
187 (8)
(Fertilizer
P2°5
kg/ha (%)
2,103 (9)
1,026 (9)
143 (6)
95 (4)
Formula)
K20
kg/ha (%)
21 (0)
11(0)
6 (0)
2 (0)
Metric conversion factors:
1 mt/ha - 0.446 T/ac
1 kg/ha = 0.89 Ib/ac.
D-8
-------
Figure D-l. Applying liquid digested sludge with a vacuum liquid
manure spreader on a bituninous strip mine spoil bank,
Figure D-2.
Applying composted sludge to a strip mine site after
top soil replacement and liming.
(Courtesy of Dr. William Sopper)
D-9
-------
cssy-'-v** . »,**
'
£*&£*$ *?<"*:?: ^ '*£*& *%&&&£&& *
Figure D-3.
Incorporation of 184 mt/ha of dewatered sludge with a
disc on an abandoned strip mine site in Pennsylvania.
(Courtesy of Dr. William Sopper)
Figure D-4.
Portion of same site as shown in Figure three
months after sludge incorporation and seeding. Note
complete lush vegetative cover. Within five years
the grass species shown was almost completely replaced
by permanent legume species.
(Courtesy of Dr. William Sopper)
D-10
-------
D.5 Seeding and Mulching
During May 27-31, 1977, the sludge-treated areas were broadcast seeded
with a mixture of two grasses and two legumes. The seed mixture used
was:
Kentucky-31 tall fescue
Pennlate orchardgrass
Penngift crownvetch
Birdsfoot trefoil
Total
Metric conversion factor:
1 kg/ha = 0.89 lab/ac
kg/ha
22
22
11
66
This seeding mixture was selected so that the two grass species would
germinate quickly, and provide a complete protective cover the first
year allowing time for the two legume species to become established and
develop into the final vegetative cover.
The seed of the two grass species was mixed together and applied with a
tractor-mounted seeder. The seed of the two legume species was innocu-
lated, mixed together, and broadcast seeded with hand-carried whirlybird
seeders. On large-scale operations, the entire seed mixture can be
broadcast seeded at one time with a tractor-mounted seeder. Immediately
after seeding, the entire 4-ha (10 ac) demonstration site was mulched
with straw and hay at the rate of 3.8 mt/ha (1.7 T/ac), although mulch-
ing is normally not necessary unless required by state regulations.
D.6 Monitoring Program
Some of the monitoring data is presented here as an example of the type
of information which are collected on reclamation projects using sludge
in Pennsylvania.
D.6.1 Vegetation Growth Responses
Vegetation growth responses were evaluated at the end of each growing
season. The results of these measurements are given in Table D-6. All
sludge treated areas had a complete cover of vegetation by August 1977
(Figure D-4), 3 months after sludge application. Both vegetation height
growth and dry matter production continually increased during the fol-
lowing 4-year period with no additional sludge additions.
D-ll
-------
TABLE D-6
VEGETATION HEIGHT GROWTH AND DRY MATTER
PRODUCTION AT THE VENANGO COUNTY DEMONSTRATION SITE
Sludge
Application
7
11
90
184
1977
29
32
34
35
Heigh
1978
37
30
41
52
t
1979
52
43
41
44
1980
55
48
49
58
Dry Matter Production
---_----___ kn/ha
7
11
90
184
6,349
7,731
4,757
6,013
9,537
8,654
7,409
9,336
18,538
17,141
13,327
11,322
34,403
26,664
26,060
31,189
Metric conversion factors:
1 rat/ha = 0.446 T/ac
1 cm = 0.3937 in
1 kg/ha - 0.89 Ib/ac.
During the first two growing seasons, the two grass species were the
dominant vegetation type on all sludge treated plots. During the second
growing season the two grasses (tall fescue and orchardgrass) produced
prolific seed heads. Seed heads were collected from 30 cm (12 in)
square plots and weighed. Results indicated a seed production ranging
from 168 to 336 kg (370 to 741 Ib) of seed per ha (150 to 300 Ib/ac).
By the third growing season, the two legume species were well developed
and had become the predominant vegetation cover on the plots treated
with liquid digested sludge and the limed dewatered sludge treated
plots. The unlimed dewatered sludge treated plots were still vegetated
primarily by the two grass species with only a few sparse patches of
legumes.
Samples of the individual grass and legume species were collected at the
end of each growing season for foliar analyses. Results for tall fescue
and birdsfoot trefoil for the highest sludge application rate are given
in Table D-7 for 1977 to 1980. Foliar trace metal concentrations gener-
ally decreased over the 4-year period. Overall, the trace metal concen-
trations were well below the suggested tolerance levels. These levels
represent the level at which a yield reduction might occur and do not
D-12
-------
represent levels at which severe toxicity occurs. There were no phyto-
toxicity symptoms observed for any vegetation on the sludge treated
areas. .
TABLE D-7
AVERAGE CONCENTRATION IN UG/G OF TRACE METALS IN THE
FOLIAR SAMPLES COLLECTED FROM THE 184 mt/ha PLOT
AT THE VENANGO COUNTY DEMONSTRATION SITE
Species
Tall Fescue
Birdsfoot
Trefoil
Year
1977
1978
1979
1980
1977
1978
1979
1980
Suggeste3 Tolerance
Level (11)
In general
(1977-1981
, the
) foil
Cu
9.4
8.6
9.2
3.5
13.9
7.7
9.2
8.2
150
In.
44.4
44.4
72.5
41.9
95.9
30.4
41.5
45.3
300
Or
0.8
0.8
0.5
1.1
1.0
0.3
1.7
1.9
2
vegetation cover improved
owing sludge application.
Pb
4.5
4.5
1.8
3.8
7.4
8.5
1.8
4.5
10
over
.No
Co
1.5
1.6
0.6
1.8
2.1
3.0
0.3
1.4
5
Cd
0.20
0.41
0.08
0.73
0.43
0.07
0.04
0.08
3
Hi
9.8
3.7
2.5
7.3
6.3
4.8
6.3
6.5
50
the five growing
deterioration in
seasons
vegeta-
mainder of the site, not treated with sludge, remained barren.
For a non-demonstration project, this type of information on vegetation
yield and quality would only have to be collected for the first year
following sludge aplication.
D.6.2 Spoils
To evaluate the effects of the sludge treatment on the chemical proper-
ties of the spoil, samples were collected at various locations and
depths at the end of each year. Results of spoil pH for the highest
sludge application (184 mt/ha; 82 T/ac) area are given in Table D-8.
Surface spoil pH generally increased over the 5-year period following
sludge application. Results indicate that the lime and sludge applica-
tions did raise the spoil' pH significantly and that the higher pH was
maintained. Under Pennsylvania guidelines, surface spoil samples must
be collected at the end of the first and second year following sludge
application to document that the pH has not dropped below pH 6.5.
Should the pH be below this level, lime must be applied to raise it to
at least 6.5.
Spoil samples were also analyzed for trace metals. A comparison of
trace metal concentrations before and after sludge was applied is given
in Table D-9. Even at the highest sludge application rate (184 mt/ha;
D-13
-------
TABLE D-8
RESULTS OF SPOIL pH FOR THE 185 mt/ha
PLOT AT THE VENAN60 DEMONSTRATION SITE
Spoil Depth
(cm)
0-15
15-30
Spoil pH
Before Sludge
3.8
3.8
1977
6.2
4.2
1978
6.7
4.6
1979
7.3
5.1
1981
6.7
5.1
Metric conversion factors:
1 rat/ha = 0.446 T/ac
1 cm = 0.3937 In.
TABLE D-9
ANALYSES OF SPOIL SAMPLES FOR EXTRACTABLE
TRACE METALS ON THE 184 mt/ha PLOT AT THE
VENANGO COUNTY DEMONSTRATION SITE
Time of
Sampling
Before sludge
applied
Four months
after sludge
applied
Eighteen months
after sludge
applied
Normal range
soil (12)
Metric conversion
1 mt/ha - 0.446
1 ug = 2.2 x 10
Spoi 1
Depth
cm
0-15
15-30
30-60
0-15
15-30
30-60
0-15
15-30
30-60
factors:
T/ac
-9 Ib.
Cu
2.5
3.0
3.7
10.8
4.0
4.9
8.8
2.5
1.8
2-
100
Zn
2.9
2.4
3.6
7.7
2.0
2.9
7.7
1.7
1.8
10-
300
Cr
0.
0.
0.
0.
0.
0.
0.
<0.
5-
3,00
2
1
2
4
1
1
2
1
1
0
Pb
uy/y
0.5
0.6
0.9
3.5
1.3
1.9
2.3
1.3
1.5
2-
200
Co
0.7
0.7
1.0
1.3
0.2
0.3
1.2
0.5
0.5
1-
40
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
7.
Cd
02
02
03
07
01
01
02
01
01
01-
0
_Ni
1
1
1
0
0
0
1
o
0
10-
1,0
.1
.0
.6
.9
.4
.5
.2
.7
.7
00
D-14
-------
82.1 T/ac) the trace metal concentrations in the surface spoil (0-15 cm;
0 to 6 in) were only slightly increased. In general, the trace metal
concentrations in the spoil were all extremely low in comparison to pub-
lished normal ranges for soils. For a non-demonstration project, soil
samples need only to be taken one year after the sludge application.
D.6.3 Water Quality
D.6.3.1 Soil Percolate Water Quality
Results of the analyses of soil percolate water at the 90 cm (36 in)
depth for the highest sludge application and the control plot are given
in Table D-10. Average monthly concentrations of N03-N in the percolate
during the summer months in the first year (1977) on the plots treated
with the highest applications of dewatered sludge were only slightly
above potable water standards (10 mg/1). The highest monthly average
was 13.0 mg/1 for August. Percolate NO^-N concentrations were surpris-
ingly low during May and June immediatefy following the sludge applica-
tion. This was probably due to the fact that rainfall during this period
was below normal. As a result, there was little opportunity for leach-
ing of nitrogen from the sludge to occur. By October, after development
of a complete vegetative cover, the concentrations of N03-N in the per-
colate decreased to levels below 10 mg/1. Concentrations of NO--N in
the percolate remained at low levels throughout 1978 to 1981.
TABLE D-10
RESULTS OF ANALYSES FOR TRACE METALS AND
NITRATE-NITROGEN FOR SOIL PERCOLATE AT THE 90-CM DEPTH
FROM THE VENANGO COUNTY DEMONSTRATION SITE
Sludge
Application
Rate Year*
mt /ha
0 1977
1978
1979
1980
184 1977
1978
1979
1980
EPA Drinking
Water Standard
C
0.
0.
0.
0.
0.
0.
0.
0.
1.
u
63
14
10
08
24
04
07
02
00
Zn
2.75
1.20
0.68
0.90
5.91
1.16
0.87
0.51
5.00
C
0.
0.
0.
0.
0.
<0.
0.
0.
0.
:r
23
05
05
06
04
01
02
01
05
Pb
0.07
0.10
0.05
0.07
0.05
0.08
0.05
0.03
0.05
Co
0.67
0.22
0.12
1.10
1.50
0.19
0.20
0.06
0.
0.
<1.
0.
0.
0.
0.
0.
0.
Cd
005
002
001
001
Oil
002
001
001
010
Ni
1.37
0.33
0.26
0.22
2.82
0.26
0.34
0.11
1.8
0.7
0.7
0.8
7.3
0.5
<0.5
0.6
10.0
* Values represent the mean of all samples collected from the plot for
the year.
D-15
-------
Average monthy concentrations of N03-N in the' percolate at the 90 cm (36
in) depth on the areas treated with, liquid digested sludge were slightly
higher than those measured on the dewatered sludge plots. The highest
concentration was 33.9 mg/1 on the 11 mt/ha (5 T/ac) plot and occurred
during the first month (June 1977) following sludge application. These
higher concentrations w.ere probably due in part to the fact that the
N03-N concentrations was higher in the liquid digested sludge (1,780
mg/1) than in the dewatered sludge (46 mg/1) and nitrate-nitrogen in the
liquid sludge is more susceptible to leaching prior to vegetation estab-
lishment. Concentrations of N03-N in percolate water started to in-
crease almost immediately after sludge application. By August 1977,
after development of a complete vegetative cover, concentrations of N03-
N in percolate decreased to levels well below 10 mg/1 and remained at
low levels throughout the study period.
Results of the analyses for dissolved trace metals at the 90 cm (36 in)
depth for the highest sludge application as well as the control plot are
also given in Table D-10.
Results indicate that percolate water quality met EPA drinking water
standards with only a few exceptions. During the first 3 months in the
first year following sludge application, the concentrations'of Zn and Ni
significantly increased and exceeded drinking water standards at the
highest sludge application rate. Concentrations of Cr and Pb slightly
exceeded drinking water standards on both the control and sludge-treated
plots. During the second (1978) and third (1979) years, only concentra-
tions of Pb exceeded drinking water standards at the highest sludge ap-
plications. These concentration increases were minimal and pose 'no
threat to human or animal health. Note that the average monthly concen-
trations of Pb on the control plot also exceeded potable water standards
during the study period (1977-1981).
Total and fecal coliform analysis were conducted on all soil percolate
water samples collected during the period May 1977 through October 1979.
No fecal coliform colonies were observed for any sample.
D.6.3.2 Ground Water Quality
Ground water samples were collected biweekly from monitoring wells to
evaluate the effect of the sludge applications on ground water quality.
Results of these analyses are given in Table D-ll. Well No. 1 was
drilled as a control outside the area of influence of the sludge appli-
cations. Ground water flow under the dewatered sludge-treated area is
toward Well No. 2 located approximately 11 meters downslope from the
plot. Results indicate that the high application of dewatered sludge
did not significantly increase the concentration of N03-N in ground
water. Concentrations of N03-N were below EPA limits for potable water
(10 mg/1) for all months sampled. It also should be noted that the
average depth to ground water in Well No. 2 was only 3 m (9.8 ft).
D-16
-------
TABLE D-ll
GROUND WATER ANALYSES FOR TRACE METALS AND
NITRATE-NITROGEN FOLLOWING SLUDGE APPLICATION AT THE VENANGO
COUNTY DEMONSTRATION SITE
Well No.
Well No. 1
(Control )
Well No. 2
(Dewatered
Sludge)
(184 rat/ha)
EPA Drinking
Water Standard
Year*
1977
1978
1979
1980
1977
1978
1979
1980
Cu
0.22
0.23
0.17
0.04
0.10
0.14
0.18
0.03
1.00
Zn
4.13
2.02
1.48
0.84
3.39
3.29
1.83
1.01
5.00
Cr
0.01
0.01
0.03
0.05
0.03
0.01
0.03
0.05
0.05
Pb
- fm
- - ^iii
0.14
0.19
0.13
0.10
0.09
0.20
0.13
0,10
0.05
Co
a/1 1 -
s/ 1 1
3.19
1.04
0.58
0.59
2.12
1.16
1.92
0.82
C
0.
0.
0.
<0.
0.
0.
0.
0.
0.
d
006
002
002
001
001
002
001
001
010
N
3.
1.
0.
0.
2.
1.
0.
0.
i
23
00
bO
51
67
26
97
72
N03-N
1.4
<0.5
<0.5
0.6
1.1
<0.5
<0.5
0.7
10.0
* Values represent the mean of all samples collected from each well for
the year.
Results of analyses of ground water samples for trace metals during the
four years after sludge was applied are also given in Table D-ll. There
appears to be no significant increase in any of the trace metal concen-
trations in Well No. 2, which was influenced by the sludge applications.
Average annual concentrations were below EPA drinking water standards.
All ground water samples collected during the period July 1977 to July
1981 were also analyzed for coliforms. No fecal coliform colonies were
observed for any sample.
D-17
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APPENDIX E
CASE STUDY OF SLUDGE APPLICATION TO
AGRICULTURAL LAND AT SALEM, OREGON
E.I Introduction
Salem, Oregon, initiated a formal program of sludge application to agri-
cultural land in 1976, known as the BIOGRO program. The system has been
highly successful, and recycles to local farmland approximately 90 to 95
percent of all sludge generated by the city's Willow Lake POTW. Infor-
mation utilized in this case study was obtained from Reference (1), and
personal communications with Ms. Dixi Druery, Director of the Salem
BIOGRO Program (2), and Mr. Tom Fisher, Environmental Specialist, Oregon
State Department of Environmental Quality (DEQ), Salem, Oregon (3).
E.2 Sludge Treatment, Quantity, and Characteristics
The Willow Lake POTW utilizes both trickling filter (old treatment
chain) and activated sludge (1976 treatment chain additions) treatment
processes. Primary and secondary raw sludge is combined, thickened, and
anaerobically digested in heated digesters. Secondary digesters store
the sludge prior to distribution for agricultural application. A small
percentage (5 to 10 percent) of the digested sludge is lagooned at the
POTW when sludge hauling is not possible due to weather or other fac-
tors. Salem is a major fruit and vegetable processing center, and
wastewater and sludge volumes increase significantly during the process-
ing months of June through September.
Annual digested sludge volume in 1982 was 121,000 m3 (32 million gal),
of which 110,000 nr (29 million gal) were applied to agricultural land.
The average dry solids content of the sludge is approximately 2.3 per-
cent, so the dry sludge solids applied to agricultural land was approxi-
mately 2,500 mt (2,800 T) in 1982.
Typical digested sludge characteristics are shown in Table E-l, based on
samples taken in early 1983. The sludge is low in metals content and
high in N content. The high N content is due to the addition of ammonia
nitrogen during the treatment process because the raw sewage contains a
high percentage of food processing wastes which are deficient in nutri-
ents. The characteristics of. the sludge vary through the year, and
daily sampling and analysis of "sludge is done as described in Section
E.5.
E.3 Sludge Application to Farmland
In 1982, sludge was applied .to approximately 1,200 ha (3,000 ac) of
local agricultural land. Application sites are located as far as 32 km
(20 mi) from the POTW, but the majority are located within an 11-km (7-
mi) radius of the POTW. At virtually all sites, the sludge is applied
only once per year.
E-l
-------
TABLE E-l
CHARACTERISTICS OF DIGESTED SLUDGE
AT SALEM, OREGON, WILLOW LAKE POTW
Constituent
Concentrationt
Constituent
Concentration
Total solids, %
PH
Total N, %
NH,-N, %
P.X
K, %
Zn, mg/kg
Cu, mg/kg
Ni, mg/kg
Cd, rag/kg
2.5
7.3
10.3
5.9
2.0
0.96
980
470
43
7
Fe,
Pb,
Ba,"
Cr,
Mg,
Ca,
Na,
As,
Co,
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
21,000
230
720
60
200
12,200
3,000
<0.1
8
* All constituents except pH reported on a dry weight basis.
t Personal communication based on samples in early 1983.
Sludge is applied at calculated agronomic rates based on N needs of the
crop (see Chapter 6). Sludge application rates average approximately
3.4 mt/ha (1.5 T/ac), and vary from 2.2 mt/ha (1.0 T/ac) to 6.3 mt/ha
(2.8 T/ac) (dry weight), depending on the N uptake of the crop grown and
the N content of the sludge applied. The N applied varies from approxi-
mately 89 kg/ha (100 Ib/ac) to 267 kg/ha (300 Ib/ac). The following
section presents the method of calculation used to determine sludge
application rates.
The crops to which sludge is applied are predominantly grains, grasses,
pasture, and silage corn. Sludge is also applied to seed crops, Christ-
mas tree farms, commercial nurseries, and filbert orchards. No sludge
is applied to fruit and vegetable crops which will be processed by local
fruit and vegetable processing plants. The DEQ requires an 18-month
waiting period after sludge application before planting of fruits and
vegetables which may be'eaten raw.
E.3.1 Determination of Sludge Application Rates
Each sludge application site is investigated prior to obtaining DEQ
approval for sludge application. If the site is approved by DEQ, an
approval letter is issued stipulating the conditions under which sludge
can be applied. Criteria and guidelines used by DEQ are summarized
below.
E.3.1.1 Soils Limitations
The soils at the proposed application site are sampled by the city of
Salem; generally, one soil sample for every 2 ha (5 ac) of site area.
Soil samples are taken at depths of 0 to 30 cm (0 to 12 in), 30 to 60 cm
(12 to 24 in), and 90 to 120 cm (36 to 48 in). Analyses are made for
cation exchange capacity (CEC), and pH.
E-2
-------
The SCS drainage classification is used by DEQ to determine when sludge
may be applied during the year. For poorly drained soils, sludge can
generally only be applied during the period from April 15th through
October 15th. For well drained soils, sludge can be applied anytime
except during or immediately after seasonal rainstorms. Other soil
drainage classifications fall between these allowable scheduling
extremes.
CEC is used to limit cumulative metal loadings added by sludge applica-
tion. Table E-2 lists these cumulative metal loadings. Note that if
soil pH is less than 6.5 (as it is in most of the Salem area), then
cumulative Cd addition is limited to 4 kg/ha (4.5 Ib/ac), regardless of
soil CEC. Since the sludge generated by Salem is very low in metals,
application sites generally have a life well over 25 years, based on
cumulative metal loadings derived from annual sludge applications.
TABLE E-2
CUMULATIVE SLUDGE METAL LOADINGS
FOR AGRICULTURAL LAND, SALEM, OREGON
CEC
(raeq/
<5
5-15
>15
L *
400 (450)
801 (900)
1,602 (1,800)
In.
_ _ _ \tn
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-------
where:
6 = Sludge application rate, in gal/ac
N = Annual N need of crop, in Ib available N/ac
S = Solids content of the sludge, expressed as a percent
M = inorganic N (NHo-N and N02-N) content of the sludge, dry weight
basis, expressed as a percent
T = Total Kjeldahl N content of the sludge, dry weight basis, ex-
pressed as a percent
Surface Application with Incorporation into Soil Within 48 Hours:
P _ 120,000 x N ,c ,
b " S (85M + 15T) {t~d)
Where all terms are identical to the formula in Equation (E-l) above.
As an example of the use of the formulas above, assume the following:
Sludge solids (S) = 2.3%.
Crop available nitrogen need (N) = 200 Ib/ac/year.
t Inorganic nitrogen (M) = 3%, dry weight basis.
Total nitrogen (T) = 6%, dry weight basis.
Given the conditions above, the sludge application rate, if the sludge
is surface-applied and not incorporated into the soil, is calculated as
fol1ows:
6 = -*-,
120,000 x 200
2.3 [(50 x 3) + 20(6 - 3)J
= 49,700 gal/ac of sludge application
Given the conditions above, the sludge application rate, if the sludge
j[S_ incorporated into the soil within 48 hours, is calculated as follows:
r = 120,000 x 200
2.3 [(85 x 3) + (15 x 6)]
= 30,250 gal/ac of sludge application
E.3.2 Application Site Constraints and Guidelines
The State DEQ investigates each proposed agricultural sludge application
site prior to giving approval for sludge application. The investigator
E-4
-------
makes his recommendations on a case-by-case basis. However, general
guidelines/requirements are as follows:
Minimum distance of sludge application to domestic wells = 61
m (200 ft). .
Minimum distance of sludge application to surface water = 15 m
(50 ft).
Minimum rooting depth (effective depth of soil) = 0.61 m (2
ft).
Minimum depth to ground water at time that sludge is applied =
1.22 m (4 ft).
Minimum distance of sludge application to public access areas
varies with the method of sludge application, as follows:
- If sludge is incorporated into soil = 0
- If sludge is not incorporated into soil = 30.5 m (100 ft)
- If sludge is pressure-sprayed ("big gun" type sprayer) over
the soil = 91 to 152 m (300 to 500 ft).
Sludge application is not approved
developments, schools, parks, etc.
close to residential
Minimum slope is largely left to the investigator's discre-
tion. Where no surface waters are endangered, slopes as high
as 30 percent have been approved. Generally, however, the
maximum allowable slope is 12 percent, and in cases where sen-
sitive surface waters are nearby, maximum slopes may be held
to 7 percent or less.
E.4 Sludge Transport and Application Methods
Sludge is hauled and applied to agricultural land virtually year around
in the Salem BIOGRO program. All hauling is done by a fleet of four
tanker trucks with a useful capacity of 20,000 1 (5,500 gal) each.
Application to specific sites is scheduled on the basis of (1) farmer
requests as a function of crop planting and harvesting patterns;
(2) period of sludge application to the specific site allowed by DEQ,
based on site soil drainage (see Section E.3.1.1); (3) weather (e.g.,
sludge is not applied during rainstorms); and (4) proximity of appli-
cation sites to each other and to the POTW.
In general, pasture and grassland receive sludge applications during the
winter months, and agricultural land, growing seasonal crops receives
sludge during the summer months, before planting or after harvesting.
Since the BIOGRO program has been in effect for 7 years, past experience
E-5
-------
enables management to anticipate which sites will require sludge during
various times of the year.
Sludge is usually applied by the haul trucks themselves, using gravity
discharge and a splash plate (see Chapter 10) to distribute the sludge
at an average rate of approximately 1,700 1/min (450 gpm) (Figure E-
3). The haul trucks are not equipped with flotation tires, so the
application site soil must be dry and firm to allow application with the
haul trucks. If the application site soil is wet, or otherwise
unsuitable for direct truck access, then a traveling big gun sprinkler
is used to spray the sludge onto the application site. In this
procedure, the haul truck is parked as close to. the application site as
practical and connected sequentially to a short discharge hose, a
portable pump (Figure E-l), portable aluminum pipe (if necessary), a
200-m (600-ft) long hose, and a big gun sprinkler (Figure E-2). The
traveling big gun sprinkler is capable of spraying liquid sludge in a
37-m (120-ft) radius at a rate of 1,360 1/min (360 gpm).
City employees do all of the sludge hauling and spreading. Three
permanent full-time drivers are used year around, and two additional
temporary drivers are added during the summer months when sludge volume
and distribution activity is increased.
E.5 Monitoring Program
E.5.1 Sludge Monitoring
Each truck load of sludge leaving the POTW is sampled. Samples are com-
posited at the end of each day, and the composite sample is analyzed for
total solids, total N, and NHg-N. A weekly sludge sample is also com-
posited, and the weekly composite sample is analyzed for total solids,
total N, NH3-N, Cd, Cu, Pb, Ni, In, chromium, P, and K. Monthly sludge
samples are analyzed for all of the constituents listed in Table E-l.
The daily composite sludge sample analysis is used to determine sludge
application rates required for various sites to meet the agronomic N
requirement of the crop being grown. The less frequent sludge analyses
are used to monitor the cumulative metal loadings being applied to each
site. Records are kept of the annual sludge application to each site,
including quantities per acre of dry solids, total N, ammonia N, and the
various metals applied.
E.5.2 Soil Monitoring
As described in Section E3.1.1, prior to receiving sludge, each site
undergoes soil sampling and analysis. During the early years of the
BIOGRO program, the city routinely analyzed the sludge-amended soil
yearly or every 3 years. Results showed virtually no change in soil
chemical and physical characteristics,' so the city no longer routinely
monitors soils at sludge application sites. Many farmers, however,
routinely have their soils tested by laboratories as a prudent agricul-
tural practice.
E-6
-------
Figure E-l.
Portable sludge pump (1).
(Note:- City also uses propane powered. Ford engine
and Cornell pump which has been very satisfactory),
Figure E-2.
Big gun sprinkler (1).
(Note: City also uses a self-propelled unit)
E-7
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Figure E-3.
BIOGROW sludge haul truck
farmland (EPA photo).
distributing sludge to
E-8
-------
E.5.3 Ground Water Monijtoring
i
During the early years of the>BIOGRO program, ground water from wells-on
or within 150 m (500 ft) of sludge application sites was sampled and
analyzed both before and after application. The constituents monitored
were N02-N, IDS, col i form, Mg, As, and methyl ene blue activated sub-
stances (MBAS). Since results showed no significant changes in ground
water quality over a period of 3 years, the ground water monitoring pro-
gram has been gradually reduced. Selected wells are now sampled approx-
imately every 3 years to check if any ground water degradation is occur-
ring.
The city of Salem and the Oregon DEQ report that background levels of
nitrate N were very high in ground water samples obtained from many of
the wells in the area north of the POTW. These high nitrate N levels
are thought to be due to the soil characteristics in this area and the
application of commercial .fertilizers over long periods. To avoid
future claims of ground water degradation, the BIOGRO program-does not
apply sludge to'areas north of the POTW.
E.5.4 Crop Sampling
The BIOGRO program conducted some limited crop tissue sampling and anal-
ysis during the initial years of the program. Constituents analyzed
included Bo, Cd, Cu, Mg, Ni, Zn, As, Pb, Mo, and Se. Results showed no
significant difference between crops grown on sludge-amended soils and
control crops. Routine crop sampling and analysis is no longer con-
ducted.
E.5.5 Surface Water Sampling
Application sites are selected to avoid the possibility of surface water
contamination, and no surface water monitoring is routinely conducted.
E.6 References
1. CHoM Hill. BIOGRO Program, Organic Solids Reuse, Willow Lake Waste-
water Treatment Plant, Salem, Oregon, June 18, 1976.
2. Personal Communication with Ms. Dixi Druery, Manager of BIOGRO Pro-
gram, Salem, Oregon, May 1983.
3. Personal Communication with Mr. Tom Fisher, Environmental Special-
ist, Oregon State Department of Environmental Quality, Salem, Ore-
gon, May 1983.
E-9
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APPENDIX F
CONVERSION FACTORS
(Metric to U.S. Customary)
Metric
Name
Centimeter(s)
Cubic Meter
Cubic Meters
Per Day
Cubic Meters
Per Hectare
Degrees Celsius
Gram(s)
Hectare
Kilogram(s)
Kilograms Per Hectare
Kilograms Per Hectare
Per Day
Kilograms Per Square
Centimeter
Kilometer
Ki 1 owatt
Liter
Liters Per Second
/
Metric Tonne
Metric Tonnes
Per Hectare
Meter(s)
Meters. Per Second
Micrograms Per Liter
Milligrams Per Liter
Square Centimeter
Square Kilometer
Square Meter
U.S.
Customary Unit
Symbol
cm
m3
m3/d
m3/ha
°C
g
ha
kg
kg/ha
kg/ha/d
kg/cm2
km
kW
L
L/s
mt
mt/ha
m
m/s
ug/L
mg/L
cm2
km*
m2
Multiplier
0.3937
8.1071 x 10~4
35.3147
264.25
2.6417 x 10'4
1.069 x 10'4
1.8(°C) + 32
0.0022
2.4711
0.004
2.205
0.0004
0.893
14.49
0.6214*
1.34
0.0353
0.264
0.035
22.826,
15.85
0.023
1.10
0.446
3.2808
2.237
1.0 ,
1.0
0.155
0.386
10.76
Abbreviation
in
acre- ft
. ft3
Mgal
Mgal/d
Mgal /acre
°F
Ib
acce
mi2
Ib
tons/acre
1 b/acre/d
lb/in2
mi
hp
ft3
gal
ft3/s
gal/d
gal /rain
Mgal/d
T
T/ac
ft
mi/h
ppb
ppm
in2
mi2
ft2
Name
inches
acre- foot
cubic foot
million gallons
million gallons
per day
million gallons
per 'acre ,
degrees Fahrenheit
poiind(s)
acre
square miles
pound(s)
tons per acre
pounds per acre
per day
pounds per square
inch
mile
horsepower
cubic foot
gallon(s) '
cubic feet per
second
gallons per day
gallons per minute
million -gallons
per day
ton (short)
tons per acre
foot (feet)
miles per hour
parts per billion
parts per million'
square inch
square mile
square foot
F-l
»U.S. GOVERNMENT PRINTING OFFICE: 1993-750- OOZ60127
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