United States
                       Environmental Protection
  Office of Water
  Washington, D.C.
EPA 832-F-00-064
September 2000
 &EPA         Biosolids
                       Technology  Fact  Sheet
                       Land Application  of  Biosolids

Biosolids are primarily organic materials produced
during wastewater treatment which may be put to
beneficial use.  An  example of such use is the
addition of biosolids to soil to supply nutrients and
replenish soil organic matter. This is known as land
application.  Biosolids can be used on agricultural
land, forests, rangelands, or on disturbed land in
need of reclamation.

Recycling biosolids through land application serves
several purposes. It improves soil properties, such
as texture and water holding capacity, which make
conditions more favorable for root growth  and
increases  the  drought tolerance of vegetation.
Biosolids application  also  supplies   nutrients
essential for plant growth, including nitrogen and
phosphorous, as well as some  essential micro
nutrients  such as  nickel,  zinc,  and   copper.
Biosolids can also  serve  as an  alternative or
substitute for expensive chemical  fertilizers.  The
nutrients in the biosolids offer several advantages
over those in inorganic fertilizers because they are
organic and are released slowly to growing plants.
These organic forms of nutrients are less water
soluble and, therefore, less likely to leach  into
groundwater or run off into surface waters.

There are several methods to apply biosolids.  The
selection of the method depends on the type of land
and the consistency  of the biosolids.   Liquid
biosolids are essentially 94 to 97 percent water with
relatively low amounts of solids (3 to 6 percent).
These can be injected into the soil or applied to the
land surface. Specialized vehicles are used to inject
biosolids into the soil, as shown in Figure  1. These
tankers have hoses leading from the storage tank to
injection  nozzles  which  release the biosolids.
Source: U.S. EPA, 1984.


Modified tanker  trucks are used  for  surface
application (Figure 2). Biosolids applied to the land
surface are usually incorporated into the soil with
conventional farm equipment.

It is often economical  to reduce the volume of
biosolids prior to transportation or storage. The
amount  of water  in biosolids  can  be reduced
through mechanical processes such  as  draining,
pressing, or centrifuging, resulting in a material
composed  of up to 30  percent dry solids.  This
material will be the consistency of  damp soil.
Dewatered biosolids do not require any specialized
equipment  and can be applied with conventional
agricultural equipment,  such as manure spreaders
pulled by tractors.

Source: U.S. EPA, 1986.
Figure 3  shows  the spraying of biosolids,  an
application method primarily used in forested or
reclamation sites.   Liquid  biosolids  are  sprayed
from a tank towed by a truck or other vehicle.

The Environmental Protection Agency's 40 CFR
Part 503, Standards for the Use and Disposal of
Sewage Sludge (the Part 503 Rule), requires that
wastewater solids be processed before they are land
applied.    This  processing  is  referred  to  as
"stabilization"  and    helps    minimize   odor
generation, destroys pathogens (disease  causing
organisms), and reduces vector attraction potential.
There are several methods to stabilize wastewater
solids,  including:

      Adjustment of pH, or alkaline  stabilization.



       Heat drying.

The Part 503 Rule defines two types of biosolids
with respect to pathogen reduction, Class A and
Class B, depending on the degree of treatment the
solids have received. Both types are  safe for land
application,   but  additional  requirements   are
imposed on Class B materials. These are  detailed
in the  Part 503 Rule and include such things as
restricting public access to the  application  site,
limiting livestock grazing,  and  controlling  crop
harvesting schedules. Class A biosolids (biosolids
treated so that there  are no detectable pathogens)
are not subject to these restrictions.

In addition to stabilization, the Part 503 Rule sets
maximum concentrations of metals which cannot be
exceeded in biosolids that will  be land  applied.
These are termed Ceiling Concentrations. Part 503
also  establishes Cumulative Pollutant  Loading
Rates for eight metals which may not be exceeded
at land  application  sites.  A third set of metals
criteria  is also included  in  Part 503, known  as
Pollutant Concentrations.  If these concentrations
are not exceeded in the biosolids to be land applied,
the Cumulative Pollutant Loading Rates  do not
need to be tracked.  Table 1 shows the three sets of
federal  limits applicable  to  biosolids  to  be land
Source: U.S. EPA, 1986.


NL = No limit
Source: U.S.
Ceiling Concentration

EPA, 1993 and 1994.
Cumulative Pollutant
Loading Rates (kg/hectare)

Pollutant Concentrations

The  term Exceptional Quality is often used to
describe a biosolids product which meets Class A
pathogen reduction requirements, the most stringent
metals limits (Pollutant Concentrations), and vector
attraction reduction standards specified in the Part
503  Rule.   Vectors (flies, mosquitoes,  rodents,
birds, etc.) Can transmit diseases directly to humans
or play a specific role in the life cycle of a pathogen
as a host.  Vector  attraction reduction refers to
processing which makes the biosolids less attractive
to vectors thereby  reducing  the  potential  for
transmitting  diseases.     Exceptional  Quality
biosolids products are as safe as other agricultural
and horticultural products and may be used without
site restrictions.


Land application is well-suited for managing solids
from any size wastewater treatment facility. As the
method of choice for small facilities, it offers cost
advantages, benefits to the environment, and value
to the agricultural community. However, biosolids
produced by many major metropolitan areas across
the country are also land applied. For example,
biosolids  from the  Blue  Plains  Wastewater
Treatment Facility serving the District of Columbia
and  surrounding  communities in Virginia and
Maryland have been land  applied since the plant
began   operation  in  1930.     The  cities  of
Philadelphia, Chicago, Denver, New York, Seattle,
and Los Angeles all land apply at least part of their
biosolids production.

Land application is most easily implemented where
agricultural  land is available  near the  site of
biosolids production, but advances in transportation
have made  land application viable  even where
hauling distances are greater than 1,000 miles.  For
example, Philadelphia  hauls  dewatered  biosolids
250  miles  to   reclaim  strip-mines in  western
Pennsylvania and New York City ships some of its
biosolids over 2,000 miles to Texas and Colorado.


Land application offers several advantages as well
as some disadvantages that  must be considered
before  selecting this option for managing biosolids.


Land application is an excellent way to recycle
wastewater solids as long as the material is quality-
controlled.  It returns valuable nutrients to the soil
and  enhances  conditions  for vegetative growth.
Land application is  a relatively inexpensive option
and capital investments are generally lower than
other  biosolids   management  technologies.
Contractors can  provide the necessary hauling and
land application equipment.  In addition, on-site

spatial needs can be relatively minor depending on
the method of stabilization selected.


Although land application requires relatively less
capital, the process can be labor intensive. Even if
contractors  are used for application, management
oversight is essential for program success.  Land
application is also limited to certain times of the
year,  especially in colder climates.    Biosolids
should not be applied to frozen or snow covered
grounds,  while farm fields are  sometimes  not
accessible during the growing season. Therefore, it
is often necessary to provide a  storage capacity in
conjunction with land application programs. Even
when the timing is right (for example, prior to crop
planting in agricultural  applications), weather can
interfere with the application.   Spring rains  can
make it impossible to get application equipment
into  farm  fields,  making it necessary to store
biosolids until weather conditions improve.

Another   disadvantage   of  land  application  is
potential public opposition,  which is encountered
most  often when the beneficial use site is close to
residential areas. One of the primary  reasons for
public concern is odor.   In worst case situations,
municipalities or counties may  pass  ordinances
which ban or restrict the use of biosolids. However,
many  successful programs  have  gained public
support  through  effective  communications,  an
absolutely essential component in the beneficial use
of biosolids.

Environmental Impacts

Despite many positive impacts to the environment,
land  application can have  negative impacts  on
water, soil, and air if not practiced correctly.

Negative  impacts  to   water  result  from  the
application  of biosolids at rates  that  exceed the
nutrient requirements of the vegetation.  Excess
nutrients   in the  biosolids (primarily nitrogen
compounds) can leach  from the soil and reach
ground water.  Runoff from rainfall may also carry
excess nutrients to  surface  water.   However,
because biosolids are a  slow release fertilizer, the
potential for nitrogen compounds to  leach from
biosolids amended soil is less than that posed by the
use of chemical fertilizers.  In areas fertilized by
either  biosolids  or  chemicals,  these  potential
impacts  are  mitigated by proper  management
practices, including the application of biosolids at
agronomic rates (the rate nutrients are used by the
vegetation.) Maintenance of buffer zones between
application areas and surface water bodies and soil
conservation practices will minimize impacts to
surface water.

Negative   impacts  to  soil   can   result   from
mismanagement of a  biosolids land application.
Federal regulations contain standards related to all
metals of concern and  application  of  biosolids
which meets these standards should not result in the
accumulation of metals to harmful levels.  Stringent
record keeping and reporting requirements on both
the federal and state level are imposed to prevent

Odors from biosolids applications are the primary
negative  impact to the air.  Most  odors associated
with land application are a greater nuisance than
threat to  human health or the  environment.  Odor
controls focus on reducing the  odor potential of the
biosolids  or incorporating them into  the  soil.
Stabilization  processes  such  as digestion  can
decrease  the  potential  for  odor generation.
Biosolids that have been disinfected through the
addition of lime may emit ammonia odors but they
are  generally  localized  and dissipate  rapidly.
Biosolids stabilization reduces odors and usually
results in an operation that is less offensive than
manure application.

Overall,   a properly  managed  biosolids  land
application program is preferable to the  use of
conventional fertilizers for the  following reasons:

       Biosolids  are  a recycled  product,  use of
       which  does  not  deplete non-renewable
       resources such  as phosphorous.

      The nutrients in biosolids are  not as soluble
       as those in  chemical fertilizers and  are
       therefore released more slowly.

      Biosolids appliers are required to maintain
       setbacks from water resources and are often
       subject to more stringent soil conservation
       and  erosion  control  practices,  nutrient

       management,  and  record  keeping  and
       reporting requirements than farmers who
       use only chemical fertilizers or manures.

      Biosolids are closely monitored.

      The organic  matter  in biosolids improves
       soil properties for optimum plant growth,
       including tilth, friability, fertility and water
       holding capacity.  They also decrease the
       need for pesticide use.

A joint policy statement of the U.S. Department of
Agriculture, the U.S. Food & Drug Administration,
and  the  U.S. Environmental  Protection  Agency
states, "...the use of high quality biosolids coupled
with  proper  management  procedures,   should
safeguard the consumer from  contaminated crops
and minimize any potential adverse effect on the
environment" (U.S. EPA, 1981).


Design  criteria  for  land  application programs
address issues  related  to  application rates  and
suitable sites.  Design criteria for physical facilities
(such  as  stabilization) that   are  part  of land
application programs are discussed in separate fact
sheets. Biosolids, site, and vegetative characteristics
are the most important design  factors to consider.

Biosolids must  meet regulatory requirements for
stabilization  and metals  content.   In  addition,
nutrient content and physical  characteristics, such
as percent solids,  are used  to  determine  the
appropriate application rate for the crop that will be
grown and the soil in which the crops will be

Site suitability is determined based on such factors
as soil characteristics, slope, depth to groundwater,
and proximity to surface water.  In addition, many
states have established site requirements to further
protect water quality. Some examples include:

       Sufficient land  to provide  areas  of non-
       application (buffers) around surface water
       bodies, wells, and wetlands.

      Depth from the soil surface to groundwater
       equal to at least  one meter.
      Soil pH in the  range of  5.5  to 7.5 to
       minimize  metal  leaching  and  maximize
       crop growing conditions.

Site suitability is also influenced by the character of
the surrounding area. While odors and truck traffic
many not be objectionable in an agricultural  area,
both will adversely impact residential developments
and community  centers close to  fields where
biosolids are applied.

The type of vegetation to be grown is also a design
consideration. Vegetation, like soil characteristics,
will generally not  exclude biosolids application
since most vegetation will benefit from the practice.
However, the type of vegetation will impact the
choice of application  equipment, the amount of
biosolids  to  be  applied,  and  the  timing  of
applications.  The effect of vegetation on the choice
of application equipment is discussed above in the
description of this technology.  The amount of
biosolids that may be applied to a site is a function
of  the  amount  of  nutrients required  by  the
vegetation and the amount of metals found in the
biosolids.  Table 2  summarizes the application
frequency,  timing, and rates for various  types of

Another factor to be considered in designing a land
application program is the timing of applications.
Long  periods  of saturated or frozen ground limit
opportunities for application. This is an important
consideration in programs using agricultural lands;
applications must be performed at times convenient
  Typical Biosolids Application Rate Scenario

  The recommended minimum amount of nitrogen
  needed by a typical corn crop to be grown in New
  Jersey  is  120  pounds  per  acre per  year.
  Biosolids containing 3 percent nitrogen could be
  applied at up to 5.4 dry tons per acre if used to
  supply all the nitrogen  needed by the crop (i.e.,
  no  other  nitrogen fertilizers  used.)   A city
  producing 10 dry tons of biosolids per day would
  require access to almost 700 acres of corn.  If the
  biosolids contained only 1.5 percent  nitrogen,
  twice  as many tons could be applied per acre,
  requiring only half as many acres to land  apply
  the same amount of biosolids generated.

Type of Site/Vegetation
Agricultural land
Small grains
Forest land
Range land
Reclamation sites

April, May, after harvest
March-June, August, fall
April-June, fall
After each cutting
Year round
Year round
Year round
Application Frequency

Up to 3 times per year
Up to 3 times per year
Once every 2 - 5 years
Once every 1 - 2 years
Application Rate

5 to 1 0 dry tons per acre
2 to 5 dry tons per acre
5 to 20 dry tons per acre
2 to 5 dry tons per acre
5 to 1 00 dry tons per acre
2 to 60 dry tons per acre
60 to 100 dry tons per acre
Source: U.S. EPA, 1994.
to the fanner  and must  not interfere  with the
planting of crops. Most application of biosolids to
agricultural land occurs in the early spring or late
fall.  As a result, storage or an alternate biosolids
management  option must be available to handle
biosolids when  application is  not possible. Forest
lands and reclamation sites allow more leeway in
the timing of applications.  In some areas of the
United States, application can proceed year round.

Application is most beneficial on agricultural land
in late fall or early spring before the crop is planted.
Timing is less critical in  forest applications when
nutrients  can  be  incorporated  into  the   soil
throughout the growing period. Winter application
is less desirable in many locales.   Rangelands and
pasturelands also are more adaptable to applications
during various seasons. Applications can be made
as long as ground is not saturated or snow covered
and whenever livestock can be grazed on alternate
lands for at least 30 days after the application.  The
timing of single applications in  land reclamation
programs is less critical  and may be dictated by
factors such as regulatory compliance schedules.


In 1995,  approximately 54 percent of wastewater
treatment plants managed biosolids through land
application, an increase of almost 20 percent from
information reported in 1993 (WEF,  1997 and U.S.
EPA, 1993.)   The vast majority of these  land
application programs use agricultural land, with
minor amounts applied to forest lands, rangelands,
or land in need of reclamation.

The use of land application increased steadily in the
1980s  for  several  reasons,  including decreasing
availability and increasing costs  associated with
landfill  disposal.   Research also helped  refine
procedures for proper land application. Meanwhile,
implementation of the Nationwide Pretreatment
Program resulted in significant improvements in
biosolids quality.  The 1993 adoption of the Part
503  Rule  created  a structure  for  consistent
application procedures across the  nation.   The
regulations were developed with input  from the
U.S. Department of Agriculture, the U.S. Food and
Drug  Administration,   biosolids   generators,
environmental groups, the public,  state regulators,
and   academic  researchers.      Conservative
assumptions were  used to create regulations to
"protect public health and the environment from all
reasonably anticipated adverse effects" (U.S. EPA,

Land application is a reliable biosolids management
option as long as the  system is designed to address
such issues as  storage or alternate management for
biosolids during periods when application cannot
take place due to unfavorable weather or field
conditions. Public opposition rather than technical
constraints is  the   most  common  reason  for
discontinuing land application programs.

 "/n fact, in all the years that properly treated biosolids
 have been applied to the land, we have been unable
 to find one documented case of illness or  disease
 that resulted."

 Martha   Prothro,  Former  Deputy   Assistant
 Administrator   for  Water,  U.S.   Environmental
 Protection  Agency.
Source: Water Environment Web, 1998.


Land   application   systems  generally   use
uncomplicated, reliable equipment.   Operations
include pathogen reduction processing, dewatering,
loading of transport vehicles, transfer to application
equipment, and the actual application. Operations
and  maintenance  considerations  associated with
pathogen reduction processing are  discussed in
other fact sheets. The other operations require labor
skills of heavy  equipment operators, equipment
maintenance personnel,  and field technicians for
sampling, all normally associated with wastewater
treatment facilities.

In addition, the biosolids generator is responsible
for complying with state and local requirements as
well as federal regulations. The biosolids manager
must be able to calculate agronomic rates  and
comply  with  record   keeping  and  recording
requirements.   In fact, the generator and land
applier must sign certification statements verifying
accuracy and compliance.  The generator should
also  allocate time to communicate with farmers,
landowners, and neighbors about the benefits of
biosolids recycling. Control of odors, along with a
viable monitoring program, is  most important for
public acceptance.


It is difficult to estimate the cost of land application
of biosolids without specific program details.  For
example, there is some  economy of scale due to
large equipment purchases. The same size machine
might be needed for a program that manages 10 dry
tons of biosolids per day as one managing 50 dry
tons per day; the cost of that machine can be spread
over the 10 or 50 dry tons, greatly affecting average
costs per dry ton.  One source identified costs for
land application varying from $60 to $290 per dry
ton (O'Dette, 1996.) This range reflects the wide
variety in  land application methods as  well as
varying methods to prepare  biosolids for land
application. For example, costs for programs using
dewatered  biosolids include  an additional  step
whereas costs for programs using liquid biosolids
do not reflect the cost of dewatering. They do,
however, include generally higher  transportation

Despite the wide range of costs for land application
programs, several elements must be considered in
estimating the cost of any biosolids land application

       Purchase  of  application  equipment  or
       contracting for application services.


       Equipment maintenance and fuel.

      Loading facilities.


       Capital,   operation  and  maintenance of
       stabilization facilities.

      Ability to manage and control odors.

       Dewatering (optional).

       Storage or alternate management option for
       periods when application is not possible due
       to weather or climate.

      Regulatory compliance,  such  as permit
       applications, site monitoring, and biosolids

      Public education and outreach efforts.

Land must also be secured. Some municipalities
have purchased farms for land application; others
apply biosolids to privately held land.

Some operating costs can be offset through the sale
of the biosolids  material.   Since  the biosolids

reduce the need for fertilizers and pH adjustment,
farmers sometimes pay to have biosolids applied to
their lands.


Other Related Fact Sheets

Odor Management in Biosolids Management
EPA 832-F-00-067
September 2000

Centrifugal Dewatering/Thickening
EPA 832-F-053
September 2000

Belt Filter Press
EPA 832-F-00-057
September 2000

Filter Press, Recessed Plate
EPA 832-F-00-058
September 2000

Alkaline Stabilization of Biosolids
EPA 832-F-00-052
September 2000

Other EPA  Fact Sheets can be found at the
following web address:

1.      O'Dette, R.G., 1996. Determining the Most
       Cost  Effective Option for Biosolids  and
       Residuals Management. In Proceedings of
       the 10th Annual Residuals and Biosolids
      Management  Conference:  10  Years of
       Progress and a Look Toward the  Future.
       Alexandria. Water Environment Federation.

2.      Sopper, W.E., Seaker, E.M., and Bastian,
       R.K., Editors, 1982. Land Reclamation and
       Biomass  Production  and  Municipal
       Wastewater and Sludge. University Park.
       The Pennsylvania State University Press.
U.S. Environmental  Protection Agency,
1995. Amendments to the Standards for the
Use or Disposal of Sewage Sludge (40 Code
of  Federal  Regulations   Part   503).
Washington,  D.C.  U.S.  Environmental
Protection Agency.

U.S. Environmental  Protection Agency,
1994.   Biosolids  Recycling:  Beneficial
Technologies for a Better  Environment.
EPA 832-R-94-009.   Washington, D.C.
U.S. Environmental  Protection Agency,
Office of Water.

U.S. Environmental  Protection Agency,
1993. Standards for the Use or Disposal of
Sewage  Sludge  (40  Code of Federal
Regulations Part 503).  Washington, D.C.
U.S. Environmental Protection Agency.

U.S. Environmental  Protection Agency,
1991.  National Pretreatment Program:
Report to Congress (EPA  21  W-4004.).
Washington,  D.C.  U.S.  Environmental
Protection Agency.

U.S. Environmental  Protection Agency,
1986, Sewage Sludge Management Primer,
Technology  Transfer Series.   Cincinnati.
U.S. Environmental Protection Agency.

U.S. Environmental  Protection Agency,
1984.   Environmental Regulations and
Technology, Use and Disposal of Municipal
Wastewater Sludge (EPA 625/10-84-003.)
Cincinnati. U.S. Environmental Protection

U.S. Environmental  Protection Agency,
1983.   Process  Design Manual  Land
Application  of Municipal  Sludge  (EPA
625/1-83-016.)     Cincinnati.    U.S.
Environmental Protection Agency.

U.S. Environmental  Protection Agency,
1981. Inter agency Policy on Beneficial Use
of Municipal Sewage Sludge. Washington,
D.C.  U.S.   Environmental   Protection

11.    Water  Environment  Federation,   1997.
      National Outlook - State Beneficial Use of
      Biosolids Activities.  Washington,  D.C.
      Water Environment Federation.

12.    Water   Environment    Web,
      Septembers,  1998.

13.    Water Quality Management Library, 1992.
      Municipal Sewage Sludge Management-
      Processing, Utilization and Disposal,  ed.
      Cecil Lue-Hing, David R.  Zenz, Richard
      Kuchenrither.     Lancaster.  Technomic
      Publishing Company, Inc.


Cecil Lue-Hing & Associates, Inc.
Cecil Lue-Hing
6101 N.  Sheridan Street, 40B East
Chicago, IL 60660

Denver Metro Wastewater Reclamation District
Steve Frank
6450 York Street
Denver,  CO 80229

District of Columbia Water and Sewer Authority
Chris Peot
5000 Overlook Avenue, S.W.
Washington, D.C. 20032

Forste Associates
Jane Forste
897 Laurel Way
Arnold, MD 21012

The  mention  of  trade  names  or  commercial
products does  not  constitute  endorsement or
recommendations for use by the United States
Environmental Protection  Agency (EPA).
For more information contact:

Municipal Technology Branch
Mail Code 4204
1200 Pennsylvania Avenue, NW
Washington, D.C. 20460
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                                                     MUNICIPAL TECHNOLOGY BRANCH