United States	EPA 832-R-94-009
Environmental Protection June 1994
Agency
Office Of Water	(4204)
&EPA Biosolids Recycling:
Beneficial Technology
For A Better Environment

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Txcedence in ccmp&ance through
opttmaftechnicalsolutions
—	
MUNICIPAL TECHNOLOGY BRANCH
Printed on Recycled Paper

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OVERVIEW
The U.S. Environmental
Protection Agency (EPA) will
continue to promote practices that
provide for the beneficial use of
municipal sewage sludge
biosolids, while maintaining or
improving environmental quality
and protecting human health.
Thousands of municipalities are
currently land applying or
otherwise recycling their
biosolids. Both agricultural and
non-agricultural sites benefit from
the nutrient and soil conditioning
value of biosolids, which is
generally worth about $100 to
$140 per agricultural application
of biosolids. Biosolids have been
used successfully in the
production of many different food,
feed, and horticultural crops; in
the production of sod and the
maintenance of turf; for improved
forest productivity; and for
reclaiming and revegetating areas
disturbed by mining, construction,
and waste disposal activities.
•	EPA continues to provide
guidance and rules for the safe
use of biosolids. Its current rule
for the final use or disposal of
biosolids (40 CFR Part 503) is the
result of nearly 10 years of
intensive study and development.
This process involved detailed
scientific risk assessment with
careful evaluation of the available
data, and the use of improved
models and more realistic
assumptions. It benefited greatly
by the extensive assistance of
biosolids experts.
•	The biosolids now being generated
are for the most part low in
pollutants, rich in nutrients and
organic matter, and highly suitable
for recycling as a result of EPA's
clean water and pretreatment
efforts. The Part 503 standards
provide for a wide range of
different end-use possibilities for
these biosolids.

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PURPOSE
This booklet is written
to provide an.
understanding of the great
value that can be derived
from the beneficial use of
biosolids. In addition, it
discusses and reaffirms
the U. S. Environmental
Protection Agency's
policy that encourages the
beneficial use of
biosolids. This booklet
then briefly discusses
important aspects of its
new regulation (40 Code
of Federal Regulations
Part 503) that govern the
final use or disposal of
biosolids. It concludes
with a discussion of the
scientific basis of the rule
and names of people and
references to contact for
additional information
regarding the rule and
risk assessment.
EPA Policy on Beneficial Use of
Municipal Biosolids
EPA's "Policy on Municipal Sewage Sludge
(Biosolids) Management" (49 FR 24358 June 12,
1984) states that:
"The U.S. Environmental Protection
Agency (EPA) will actively promote those
municipal [biosolids] management
practices that provide for the beneficial use
of [biosolids] "while maintaining or
improving environmental quality and
protecting public health. To implement
this policy, EPA will continue to issue
regulations that protect public health and
other environmental values... Local
communities will remain responsible for
choosing among alternative programs; for
planning, constructing, and operating
facilities to meet their needs; and for
ensuring the continuing availability of
adequate and acceptable disposal or use
capacity."
As noted in the policy statement, EPA prefers
well-managed practices that beneficially use
municipal biosolids. Such practices include land
application of biosolids as a soil amendment or
fertilizer supplement and various procedures that
derive energy from biosolids or convert them to
useful products. These practices can help reduce
the volume of biosolids requiring disposal, thus
reducing the rate at which the limited capacity of
disposal facilities is exhausted. Other benefits
derived from recycling biosolids include
improved soil fertility and tilth, reduced need for
and enhanced response to inorganic fertilizers,
better growth and quality of crops, and decreased
consumption of energy.

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Silvigrow applications vehicle at the University of Washington Pack Forest
facility.
Composted biosolids have enhanced the Mt. Vernon landscape.

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Biosolids are a
Natural Fertilizer
For many individuals sewage sludge
(biosolids) induce a major emotional
response. This response is
understandable when you realize that
ever since infancy, parents teach
children that human waste is dirty and
is to be avoided and flushed down the
toilet. Compare this with the life-long
experience of most persons familiar
with animal wastes as a material to be
managed and used.
Like animal waste, biosolids are a
part of the natural cycle of life (Figure
1). They contain inorganic and
organic compounds removed during
wastewater treatment. An important
perspective on biosolids — the natural
fertilizer — can be gained from the
following closer look;
"Crops that supply our food and
animal feed are grown in the soil.
To grow, the crops need fertilizer
and water. Essential soil fertilizer
nutrients include carbon, hydrogen,
oxygen, phosphorus, potassium,
nitrogen, sulphur, calcium, iron,
magnesium, molybdenum, boron,
copper and zinc. Plants take up
these essential soil-borne nutrients
that are necessary for their normal
growth. Using these nutrients and
sunlight, plants manufacture organic
carbon-rich foodstuffs such as
carbohydrates, fats, and proteins.
Sun and rain cause crops to make
carbon rich foods and provides energy
for uptake of nutrients such as nitrogen,
potassium, phosphorous, zinc, and
molybdenum
The same nutrients that are
essential for plant growth also are
essential for the growth of humans
and other animals. We gain many
of these essential nutrients, along
with carbohydrates, fats, and
proteins, by eating plants. Wastes
are excreted from humans and
contain these same essential
nutrient elements that are in the
mm

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animals eat plants to obtain the same
trients and carbon rich foods for growth
Humans eat animal and plant
foods to obtain nutrients and
carbon rich foods for growth
Plant residues and fetal matter
and wastes from farm animals
and humans are returned to the
soil to support plant growth
igure 1. Natural Cycling of Nutrients
foods we consume. These wastes go
into the municipal sewer system along
with other household wastes.
Municipalities also collect and treat
wastewater from industrial and
commercial sources. The residual
solids generated during wastewater
treatment were previously called
sewage sludge. Sewage sludges that
can be used are now being called
biosolids to emphasize the beneficial
nature of this valuable recyclable
resource. Properly prepared biosolids
provide a rich source of the essential
fertilizer elements needed by plants to
produce food. It seems only natural to
return this rich source of nutrients and
organic matter back to the soil to
perpetuate the cycle of life."
5

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Declining Cadmium (mg/kg) in Biosolids at the
Hyperion Wastewater Treatment Facility
50
40
30
20
10
1989A 1989B 1990A
Semi Annual Periods
1990B
Figure 2. Pretreatment and source control have been very
successful in reducing pollutant levels in biosolids.
Appropriate control is needed for
the safe agricultural use of all
fertilizers and soil conditioners —
whether in the form of biosolids, other
organic amendments, or chemically-
based fertilizers — to insure that the
proper amount of essential elements
are provided. Controls also are
needed with all fertilizers and soil
conditioners to avoid contamination of
groundwater with leachable excess
nitrogen. Controls are needed with
biosolids and animal wastes, because,
depending upon the level of treatment,
disease-causing organisms (pathogens)
may be present and vectors such as
flies and rodents can be attracted that
may transmit disease. These controls
come from many sources. Some
control comes from following State
fertilizer recommendations and sound
agricultural practices. Additional
control is obtained by required
wastewater treatment to reduce
pathogens to levels that are not
harmful. Pretreatment by industry,
mandated by law, is another primary
control that prevents excessive levels
of unwanted pollutants in wastewater
and the resultant biosolids. Figure 2
shows that pretreatment and source
control have been very successM in
reducing the levels of pollutants in
biosolids. And finally, compliance
with the new Federal as well as
existing State regulations requires the
6

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careful implementation of management
practices and the use of biosolids
application rates based on crop needs.
Agricultural Use of Biosolids
EPA's policy that promotes the
beneficial use of municipal biosolids is
based on years of extensive study and
experience. Hundreds of studies have
been conducted as a basis for the safe
use of biosolids. Moreover, thousands
of publicly owned treatment works
(POTWs) are currently using their
biosolids as an organic fertilizer and
soil conditioner on land throughout the
United States. For example, over
55% and 90%, respectively, of all
biosolids produced in Ohio and
Maryland are used on land.
Examples of communities recycling
their biosolids include Hannibal, MO
(19,000 population), Madison, WI
(250,000 population), and Seattle, WA
(1.1 million population). Each of
these municipal authorities have been
winners in EPA's National Beneficial
Use of Biosolids Awards Program.
Hannibal, MO and Madison, WI
charge farmers for using their
biosolids. Hannibal recovers 100% of
the costs of hauling and spreading
biosolids from its sales to farmers,
This corn crop benefitted from the use of biosolids as a fertilizer.

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Table 1. Value of 5 to 10 Dry Tons per Acre of a Typical
Anaerobically Digested Dewatered Biosolids Applied to Farmland
Nutrient
lbs/Acre Applied
Value/Acre
Nitrogen
150
$ 30.00
Phosphorus (P205)
150
$ 30.00
Potassium (K20)
10
$ 1.00
Copper (Cu)
7
$ 14.00
Zinc (Zn)
10
$ 12.50
Sulfur
20
$ 10.00
Lime
1 ton
$ 28.00
Spreading

$ 15.00
Total Value*

$140.00
Value of organic matter is in addition to this total

Madison receives $12 per acre for
applying their biosolids. Madison
fertilizes 3,000 to 4,000 acres of
farmland with biosolids each year and
has farmers waiting with a total of
22,000 acres of farmland available for
application. Seattle applies biosolids
to forest as well as agricultural land.
Since 1974, all the biosolids from
metropolitan Washington, DC (3
million population) have been used on
land. In 1993 about 75% (87,000 dry
tons) of the dewatered biosolids
produced was used on agricultural land
in Maryland (4,000 acres) and
Virginia (4,000 acres). The remaining
25% was composted for use by
8
landscapes, horticulturalists, and the
general public. The dewatered
biosolids were applied to private
farmland by private contractors at no
charge to the farmers. The farmers
received $100 to $140 worth of
needed nitrogen, phosphorus, trace
nutrients, lime, and organic matter per
acre from each 5 to 10 dry ton per
acre application of biosolids (Table 1).
An additional benefit of biosolids
is its suppression of pathogenic soil
organisms such as nematodes that
damage plant roots as well as specific
plant root diseases that otherwise
cause damage to commercially grown
potted plants.
/»>sv
1 y
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Non-Agricultural
Use
of Biosolids
The beneficial uses of
biosolids are not limited
to farmland application.
Biosolids are used in
silviculture to increase
forest productivity and to
revegetate and stabilize
lands that have been
harvested or disturbed by
mining, construction,
fires, land slides, or other
natural disasters.
The application of
biosolids to forest land
can shorten pulp wood
and lumber production
cycles by accelerating
tree growth, especially on
marginally productive
soils. Studies by the
University of Washington
in the Northwest, and the
U. S. Forest Service in
the Southeast, on the use
of biosolids as a fertilizer
in silviculture have shown
as much as a three-fold
increase in tree growth
compared to controls for
certain tree species.
--v.
p	Wi1!" »
gS*.
Bipsojids applied during
FTthis growth period
£"'.(9 years before)
A cross-section of a Douglas fir tree
demonstrates how biosolids increase tree
growth.
9

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Biosolids are used productively to
stabilize and revegetate areas
destroyed by mining, dredging, and
construction activities. Alkaline-
stabilized, digested, air-dried, and
composted biosolids are frequently
used to help revegetate mine spoE,
highway embankments and median
strips, and other construction sites.
Alkaline-stabilized biosolids are also
used as a soil substitute for
intermediate and final landfill cover.
The use of biosolids in land
reclamation efforts has proved very
successful and comparable in cost to
other commercial methods in both
large- and small-scale projects. For
example, in a strip-mined area in
Fulton County, IL, reclamation using
municipal biosolids costs about $3,700
per acre, as compared with a range of
$3,400 to $6,300 per acre using
commercial methods.
Studies in New Mexico have shown
sustained improved growth and
nutritional quality of desirable native
vegetation on rangeland and reduced
run-off of rain water from a one-time,
10 to 20 dry tons per acre surface
application of biosolids. Studies in
Colorado, with 1 to 15 dry tons per
acre of biosolids applied, are being
conducted to determine optimum rates
to improve range quality and minimize
public health and environmental risks.
Early results from these studies show
similar improvements in range quality
and reduced water runoff proportional
to the rate of biosolids application.
Biosolids have been used to reclaim
over 3,000 acres of lands devastated
by mining and smelting activities in
Pennsylvania. Biosolids are being
used in combination with fly ash to
revegetate soils at that Palmerton, PA,
site which has been included on EPA's
list of Superftind Sites. The
Palmerton site was so highly
contaminated from 90 years of
smelting zinc that all vegetation in the
surrounding area was destroyed. The
research team members from
Allentown, PA, and the Pennsylvania
State University, who were
responsible for demonstrating the
viability of the reclamation
procedures, were recognized as
winners in EPA's first National
Beneficial Use of Biosolids Awards
Program (1988).

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Above, truck spraying
biosolids/fly ash mixture
for revegetation at the
Palmerton, Pennsylvania,
hazardous waste site. Right,
the same area after being
reclaimed.
¦.t%at£3Rf

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Biosolids Recycling: Practices and Benefits
Biosolids may be used
separately or in
conjunction with chemical
fertilizers. Figure 3A
shows the comparative
use of chemical fertilizers
with and without 8 dry
tons per acre of biosolids
applied to sandy irrigated
soils near Yuma, AZ.
Figure 3A shows the
comparative usage during
the first year after
biosolids application
where only about one-
fourth as much chemical
fertilizer was needed. By
the third year of biosolids
application, no
supplemental chemical
fertilizer was required.
Figure 3B shows that
the yield of three crops
was greatly enhanced
compared with their
yields on both chemically
fertilized and unfertilized
controls.
Particularly in soils that
are low in organic
matter, biosolids provide
benefits that are not
available from chemical
fertilization. The
biosolids' organic matter
content enhances the soil
12
Fewer Pounds per Acrs of Chemical Fertilizer Nutrients
Were Needed When Biosolids Were Used
400-
300 •
200-
100
327
156
rm
Nitrogen
Phosporus
Potassium
l/V ! \ Less	V//\ More
Chemical Fertilizer	Chemical Fertilizer
WITH Biosolids	WITHOUT Biosolids
Figure 3A
Comparative Yield of Crops Due to
Chemical Fertilizers vs. Biosolids

Barley
Horse Hay
Cotton

Control 0
01 Chemical
Fertilizer
m Biosolids
"J Amended
Ag Tech - 1989
Figure 3B
' Jiu



A- f. > -IjV*

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rooting media thus providing for better
water retention, improved air
exchange around plant roots, and
increased ability of the soil to hold
nutrients in a plant-available state
(increased cation exchange capacity).
In sandy, highly leachable soils, the
tendency for biosolids' organic
nitrogen to be released at a rate that is
consistent with plant uptake, mitigates
the loss of excess nitrogen into
groundwater.
The biosolids' organic matter had
other impacts on the same Yuma, AZ
farm that initially might have seemed
undesirable. Herbicides became less
effective because of their interaction
with the changing sandy soil and
organic biosolids matrix. Those
fields, previously weed-free, now
contained more weeds. On the other
hand, the plants became more
vigorous and better able to compete
with weeds and withstand damage
from insect pests. The changes that
occurred because of biosolids usage
allowed the farmer to decrease his
costs for fertilizer, herbicides,
and pesticides by approximately $170
on each acre of his 12,000 acre farm.
Comparative plant vigor on sandy Yuma, AZ, soil without (left) and with
(right) biosolids amendments.

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In some instances the total yield
decreased compared to weed-ftee
fields. However, the farmer's net
return per acre increased (more dollars
per acre profit). The same Yuma, AZ
farmer, because of Ms enhanced yield
and lowered costs from use of
biosolids, decided to dedicate 10% of
his land each year to producing grains
for wildlife. Because of the farming
changes that left more cover from
weeds on all 12,000 acres and the
1,200 acres left each year with
unharvested grain for wildlife, the
dove and other wildlife population
increased so substantially in 6 years
that the Yuma region began to realize
an unexpected $3.5 million increased
annual benefit from hunting-related
activities.
Other Uses for Biosolids
The sale of biosolids products to the
public for many kinds of garden,
nursery, household, and lawn uses
continues to increase. Treatment such
as heat-drying, composting, and
treatment with alkaline materials
convert biosolids into useful products
that can be considered "exceptional
quality" if pollutant concentrations in
the biosolids do not exceed the
minimum levels specified in Table 3
of the Part 503 rule. These products
are safe for unrestricted use by the
general public. Generators of these
products are required to have an
Increased populations of birds over
biosolids-amended farm fields in Yuma,
ongoing monitoring program to ensure
that the biosolids continually meet the
"exceptional quality" requirements.
Examples of these stabilized
products include Milwaukee's heat-
dried biosolids product,
"MILORGANITE,"" which it has been
producing and selling throughout the
United States since the 1920's.
Products of this nature have sold in
bulk for as for as much as $190
per ton if high in nitrogen content and
aesthetically pleasing. Kellogg Supply
Company (a private firm in California)
has been producing and marketing
composted biosolid products
* Vendor and trade names are included for the benefit
of the reader and do not imply endorsement by EPA.
14

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(e.g., NITROHUMUS, TOPPER,
GRO-MULCH) mostly in California,
Arizona, and Nevada for a similar
period of time. Their products include
composted biosolids that have come
predominantly from Los Angeles
County, CA, wastewater treatment
facilities. Both MILORGANITE and
NITROHUMUS have been used to
establish and maintain grass playing
fields in sports stadiums across the
country — including the Rose Bowl.
A composted biosolids product from
Philadelphia called EARTHGRO has
been used with great success for
growing container plants and
chrysanthemums. Even the White
House has used composted biosolids to
reestablish its lawns. Several years
ago, 825 tons of composted biosolids
(COMPRO) were used in this highly
successful project. Similarly, the
lawns at Mount Vernon, the
Washington Monument Grounds and
the Governor's Mansion in Annapolis,
MD, were renewed with COMPRO.
The first use of composted biosolids
on the Washington, DC Mall (nearly
6,000 tons) was in 1976 to establish
the Constitution Gardens in time for
the United States Bicentennial Birthday
celebration. COMPRO is currently
being sold for $10 to $50 per cubic
yard in bulk depending on quantity
RBBBScnpr^cls have yielded! impressive results. Corn plants on the
left were grown in biosolids-amended soil.

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delivery. The cost
for their bagged
product is $5 to $6
per cubic foot.
Comparative Percentage Uptake of Lead from
Soil With and Without Biosolids into Bones
of Test Animals
(In the Test, Complete Diets for the Test Animals were Amended With
9% High-Lead Soil With and Without 1% of Five Different Types of
Biosolids)
140
120
100
Current research by
Heneghan, et.al.
regarding the
potential use of
biosolids to remediate
soils containing high
levels of lead by
reducing the soil lead
bioavailability shows
promise. The
research is indicating
that appropriately
produced and applied
biosolids may help
protect child health
because the biosolids
matrix reacts with the
lead in contaminated
soils to reduce the
bioavailability of the
soil lead. The
research involved the
feeding of laboratory animals an
otherwise completely balanced diet
that also containing 9% of either a low
or high-lead containing urban soil
mixed with 1 % of different biosolids
products.
Heneghan, et.al
Control
(High-Lead
Soil Without
Biosolids)
High-Lead Soil Plus Five
Different Types of Biosolids
The preliminary results from these
animal feeding studies, depicted in
Figure 4, show up to 50% reduced
bioavailability of ingested lead, (i.e.,
reduced absorption of ingested soil
lead into the blood and body tissues
16
Figure 4. Biosolids can reduce the bioavailability
of soil lead
reflected by bone levels). Such data
suggest that children ingesting
biosolid-treated soil and dust may have
a decreased absorption of lead into the
blood stream, thus lessening the
potential for lead-induced nerve and
brain damage. Additional research is
needed with laboratory animals to
determine the best form of biosolids to
use and the reduction of bioavailability
that is possible.
Another stabilization method that is
f 5^


Z* 7,.v

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commonly used by many wastewater
treatment works is anaerobic
digestion. This stabilization process
generally yields a Class B biosolids
product as defined in EPA's Part 503
rule that has been spread for years on
agricultural land in liquid form and as
a dewatered product. One of the most
economical and agriculturally
beneficial methods for using biosolids
is the land application of this type of
stabilized product.
Methane gas is generated during the
anaerobic digestion process and has
considerable value. For example, the
Tampa, FL, treatment works recovers
about $700,000 worth of electricity
each year from methane it produces
during anaerobic digestion. This is
equivalent to approximately $65 worth
of net electricity being produced per
dry ton of volatile biosolids removed
from the digester. Tampa also uses
the heat removed from the electrical
generators to provide more than 95%
of the warmth needed for the
digesters. All but 10 to 15 % of
Tampa's anaerobically digested
biosolids are being heat-dried and
marketed for between $85 to $120 per
dry ton. The balance is being land
applied in dewatered form. Tampa
was recognized for this highly efficient
operation in EPA's 1992 Beneficial
Use of Biosolids Awards Program.

A 500-kilowatt engine and generator using biosolids
digester gas to produce electricity.
17

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Expert Opinions Regarding
Biosolids Useability
In 1981, Del Monte Corporation,
along with other food processors, .
announced that they would no longer
accept fruit and vegetables for
processing that had been grown on
biosolids treated soils. Officials from
the U.S. Department of Agriculture
(USDA), the Food and Drug
Administration (FDA), and EPA met
with representatives of the National
Food Processors Association to
address the food processor's concerns.
After analyzing the available
health and safety information
pertaining to these practices, the
USDA, FDA, and EPA issued
guidance and a joint policy statement
in 1981 that was signed by the
Administrators of each Agency. The
Agencies endorsed using biosolids on
land for producing fruits and
vegetables, and concluded:
"that the use of high quality
[biosolids], coupled with
proper management
procedures, should safeguard
the consumer from
contaminated crops, minimize
any potential adverse effect on
the environment," and
"that, with the adherence to
the guidance contained in this
document, the safety and
wholesomeness of the fruit
and vegetable crops grown on
[biosolidsj-amended soils will be
assured."
In 19B3, over 200 health and
environmental experts from the United
States, Canada, and Europe met in
Denver, CO, to assess the state of the
art for biosolids use and disposal (ten
years after a similar meeting in
Champaign, IL). These experts
arrived at a published consensus that
the existing guidance and regulations
were adequately protective of public
health and the environment, provided
that biosolids were used in accordance
with those provisions. They
concluded:
"Guidelines have been
developed to enable the
environmentally safe use of
[biosolids] containing median
concentrations of metals and
organics when the [biosolids]
are applied at agronomic
rates based upon nitrogen or
phosphorus utilization by
crops."
"Groundwater monitoring for
nitrate-nitrogen is not needed
where [biosolids] nitrogen
additions do not exceed
fertilizer nitrogen
recommendations for the crop
grown."
"Using [biosolids]for
reclamation of disturbed land

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1
Sampling composted biosolids for pathogen analysis. Studies show that
properly composted biosolids are safe for use.
at rates higher than those for
agricultural land, when
properly implemented and
managed, improve the quality
of soils, groundwater or
vegetation."
"With proper management
and safety allowances based
on research data, land
application is a safe,
beneficial and acceptable
alternative for treatment of
municipal wastewater and
[biosolids]."
Some concern has been expressed
about the possibility that land-applied
biosolids might damage crops,
livestock, or the land itself resulting in
possible financial loss to the fanner or
his mortgage lender. Some concern
has also been expressed about possible
future loss that might occur if new
discoveries were to show unanticipated
hazards from previous biosolids use.
While there can be no guarantees,
past experiences with agronomic use
of biosolids have been very
reassuring. Where biosolids have
been applied in accordance with
regulations, problems that have
occurred are rare and are generally
related to inadequate field management
and not biosolids quality — virtually
the same type of problems which have
occurred from other normal farming
practices. All research to date leads
to the conclusion that the agronomic
use of high quality biosolids is
sustainable and very safe.
19

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Final Part 503 Standards for the Use or Disposal of Biosolids
Overview of the
Development
of the Rule
Each series of biosolids guidance
and regulations, developed by EPA
since the mid 1970's, has been based
upon the most recent knowledge about
the risks and benefits of disposing and
using biosolids. Over time, the
amount of information and
understanding obtained from research
and operational experience upon which
these efforts were based
has continued to increase. The EPA
effort to determine what would be
permissible increases in soil and crop
pollutant contents as a result of
biosolids additions to land has been
scientific and conservative and has
involved the expert assistance of
USDA and other cooperating
institutions. This EPA approach
contrasts with the policy-based
approach taken by some other
countries to limit increases of
pollutants in soils to some small
fraction of "background environmental
Table 2A. Most Limiting Pathway for Each Biosolids Pollutant
Remaining in the Final Part 503 Rule*
Sludge Pollutant
Highly Exposed
Most Limiting

Individual
Pathway
Arsenic
Biosolids eaten by child
3
Cadmium
Biosolids eaten by child
3
Chromium
Phytotoxic plant
8
Copper
Phytotoxic plant
8
Lead
Biosolids eaten by child
3
Mercury
Biosolids eaten by child
3
Molybdenum
Animal eating feed
6
Nickel
Phytotoxic plant
8
Selenium
Biosolids eaten by child
3
Zinc
Phytotoxic plant
8
" The regulatory limit for each pollutant was based on the exposure pathway found to be the most
limiting for that pollutant.


HiH

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Table 2B. Most Limiting Pathway for Each Biosolids Pollutant
Deleted from the Final Part 503 Rule **
Biosolids Pollutant
Highly Exposed
Most Limiting

Individual
Pathway
Aldrin
Eating animal fat/milk
5
Dieldrin
Eating animal fat/milk
5
Benzo(A)Pyrene
Biosolids eaten by child
; 3
Chlordane
Biosolids eaten by child
3
DDT/DDD/DDE
Eating fish
12
D imethylN itrosamine
Biosolids eaten by child
• 3
Heptachlor
Eating animal fat/milk
; 5
Hexachlorobenzene
Eating animal fat/milk
i 5
Hexachlorobutadiene
Eating animal fat/milk
5
Lindane
Biosolids eaten by child
; 3
PCB's
Eating animal fat/milk
: 5
Toxaphene
Eating animal fat/milk
; 5
Trichloroethylene
Biosolids eaten by child
3
** Pollutant deleted because (1) it was not present in NSSS studied biosolids, (2) it was only
present in biosolids at levels about 10 to 100 times below the pollutant limits calculated by risk
assessment for biosolids to be protective of human health and the environment, or (3) the
pollutant has been banned by EPA and is no longer being manufactured or used in the United
States.
levels" without careful assessment of
positive or negative impact.
As a result of the statutory directive
in Section 405 of the Clean Water
Act, EPA has expanded its regulatory
efforts by developing a new
comprehensive risk-based rule for
biosolids. In this expanded
effort, which began in 1984, EPA
increased the number of pollutants
considered to over 50. However,
after careful screening and analysis,
the Agency reduced this to a list of 25
crucial pollutants (Tables 2A/2B).

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Risk from exposure to these 25
pollutants was evaluated via 14
different public health and
environmental pathways (Table 3).
The new method, which was
established for conducting this
multimedia risk assessment, was
reviewed and approved by EPA's
Science Advisory Board.
Many careful decisions were made
during this intensive effort to select
data that was more representative,
assumptions that were more realistic,
and models that were more
appropriate. This effort has resulted
in a final rule with many of the
proposed standards becoming less
restrictive and complex than
previously believed necessary because
of the more comprehensive and
appropriate research data base,
assumptions, and modeling.
Rule development will continue.
Additional pollutants may be added to
or deleted from the Part 503 rule, and
restrictiveness may change. One
example of change in the Part 503 rule
was the elimination from the
regulation, after initial proposal and
subsequent evaluation, of 14 toxic
organic pollutants. The basis for
elimination is discussed in a later
section of this document entitled
"Features of the Risk Assessment
Process" and are also listed in a
footnote to Table 2.
22


-	* i.-sj ¦ ¦ ¦ •<,"¦ ¦,,
Table 3
PATHWAY
1	Biosolids-Soil-Plant-Human
2	Biosolids-Soil-Plant-Human
3	Biosolids-Soil-Human
4	Biosolids-Soil-Plant-Animal-
Human
5	Biosolids-Soil-Plant-Human
6	Biosolids-Soil-Plant-Animal
7	Biosolids-Soil-Animal
8	Biosolids-Soil-Plant
9	Biosolids-Soil-Soil Biota
10	Biosolids-Soil-Soil Biota-Biota
Predator
11	Biosolids-Soil-Airborne Dust-Human
12	Biosolids-Soil-Surface Water/Fish-
Humans
13	Biosolids-Soil-Air-Human
14	Biosolids-Soil-Groundwater-Human

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athways of Exposure from Land Application of Biosolids
DESCRIPTION	;
Consumers in regions heavily affected by landspreading of biosolids ;
Farmland converted to residential home garden five years after reaching
maximum biosolids application
Farmland converted to residential use five years after reaching maximum
biosolids application with children ingesting biosolids-amended soil :
Households producing a major portion of their dietary consumption of animal
products on biosolids-amended soil
Households consuming livestock that ingest biosolids-amended soil while grazing
Livestock ingesting food or feed crop grown in biosolids-amended soil
Grazing livestock ingesting biosolids/soil
Crops grown on biosolids-amended soil
Soil biota living in biosolids-amended soil
Animals eating soil biota living in biosolids-amended soil	,
Tractor operator exposed to dust from biosolids-amended soil	|
Humans eating fish and drinking water from watersheds draining biosolids-
amended soils
Humans breathing fames from any volatile pollutants in biosolids
Humans drinking water from wells surrounded by biosolids-amended soils

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Expert Assistance with the
Rule and Risk Assessment
The best scientific talent and data
were assembled and used to structure
the final Part 503 rule. Twelve
experts (Table 4) with extensive
Table 4. Expert Cooperators in the Part 503 Risk Assessment
Dr. Rufus Chaney
Dr. Andrew Chang
USDA-ARS
Dept. of Soil & Environmental Science
Beltsville, MD
University of California

Riverside
Dr. Willard Chappell
Dr. Lawrence Gratt
Center for Environmental Science
IWG Corporation
University of Colorado
San Diego, CA
Denver

Dr. Robert Griffin
Charles Henry
Dept. of Chemical Engineering
College of Forestry Resources
University of Alabama
University of Washington
Birmingham
Seattle
Dr. Terry Logan
Dr. George O'Connor
Dept. of Agronomy
Dept. of Soil Science
Ohio State University
University of Florida
Columbus
Gainesville
Dr. A1 Page
Dr. Jim Ryan
Dept. of Soil & Environmental
Risk Reduction Engineering Lab
Science
US EPA
University of California
Cincinnati
Riverside

Dr. Robert Wagenett
Dr. John Walker
College of Agriculture & Life
OWEC
Science
US EPA
Cornell University
Washington, DC
Ithaca

24
experience in the field of evaluating
the benefits and risks of using
biosolids assisted in its formulation.
These experts, who collectively had
over 300 years of training and
research experience, were from
Universities, EPA, and other Federal

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Agencies. The carefully reasoned
science and policy decisions which
occurred have provided the best rule
ever developed for governing the use
or disposal of biosolids. EPA believes
that this Part 503 rule fully meets the
Congressional mandate to be
protective of public health and the
environment and allows for the safe
and effective recycling of biosolids —
indeed providing beneficial technology
for a better environment.
Features of the Risk
Assessment Process
The following brief examples
describe some of the valuable
information that has come from
extensive research by EPA and others
on the safe and continuing use of
biosolids. The examples show how
this information was used in the
scientific risk assessment that resulted
in a comprehensive, sometimes less
restrictive, and simplified final Part
503 rule.
Research has shown that the
biosolids-organic-chemical matrix
greatly impacts the plant
uptake/bioavailability of pollutants,
even after the biosolids have been
mixed with soil. This means that
certain pollutants cannot be drawn into
the plant because they are bound in a
form that is unavailable to the plant.
Data from sites that are nearly 100
years old show that this binding effect
does not change over time. Hence,
only data from field experiments
where biosolids had been applied were
used, not data from chemical salts
applied to soils.
Another area of intensive study and
data review centered on the issue of
potential cadmium toxicity. It was
found that most crops grown in
biosolids-amended soils do not take up
high levels of cadmium. Those
sensitive crops that do accumulate
cadmium (generally vegetables) also
accumulate calcium, iron and zinc,
other elements that are contained in
biosolids. Hence, persons eating
"sensitive" accumulator crops will
simultaneously ingest all those
elements. Studies have shown that
calcium, iron and zinc inhibit
cadmium absorption in Che intestine of
individuals — thus preventing levels of
this metal from accumulating. Hence,
the use of this information in the risk
assessment process led to a Part 503
cadmium limit being less restrictive
than when the rule was proposed.
Another example of how
information was developed to
formulate the final rule came from the
National Sewage Sludge Survey
(NSSS) conducted in 1988. In this
survey, biosolids analytical data from
about 200 statistically representative
treatment plants across the United
States were reviewed for the
prevalence of more than 400 toxic
organic pollutants. The scientific
review of this data revealed that a

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majority of the toxic organic pollutants
were not present in biosolids at
detectable levels and that risk
assessment for the various toxic
organic pollutants under consideration
showed no anticipated adverse effects
at the levels that were detected. This
information, coupled with the fact that
many of these toxic organic pollutants
were no longer manufactured or in
use, led to the decision not to include
these pollutants in the final rule.
Part 503 Rule Has
Conservative Elements
Even though research has shown
that pollutant uptake by crops grown
in biosolids-amended soils is less than
linear (i.e., less than directly
proportional to the amount of
biosolids-contain ed pollutant that was
added to the soil), the assumption used
for the Part 503 risk assessment was
that pollutant uptake by crops is linear
(Figure 5). This means that the risk
assessment assumes greater uptake of
pollutants into plants and hence
exposure to the humans and the
environment than actually occurs.
EPA has also continued to use the
conservatively established risk-
reference-doses in the risk assessment
for the final rule to estimate the lowest
amount of pollutant that the highly
exposed individual in each pathway
can safely tolerate. The toxicological
studies that were used to establish
many of the risk-reference-doses often
Metal Uptake by Plants
Metal Level in Biosolid — Amended Soil
Figure 5. Conservative Assumption of Metal Bioavailability to Plants
26

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were based on studies in which pure
chemical doses of the pollutants were
fed directly to the test animal without
food or injected directly into the
animal. These procedures
overestimate risks because the actual
bioavailability and toxicity of
pollutants are much less when the
pollutants are in a biosolids- or food-
borne matrix than when the pure
chemical form is placed directly in the
stomach or injected directly into blood
stream of the test animal.
High Quality Biosolids as a
Product
A major simplification of the rule
resulted because additional research
and risk analyses showed that an
exceptional quality (EQ) biosolids
product with low levels of pollutants
and highly reduced pathogen and
vector attractiveness can be safely
used by the general public in a manner
similar to any other commercial
fertilizer/soil conditioner product.
Once the Part 503 requirements for
EQ biosolids are met (this includes
continued demonstration of EQ quality
by periodic monitoring, record
keeping, and reporting), there is no
further regulation by the Part 503 rule.
EQ biosolids are generally produced
by composting, heat-drying, or
stabilization with alkaline materials.
Equally Protective Regulatory
Options
The Part 503 rule includes several
options for regulating the uses of
biosolids - each with different levels
of control. Each of the options is
equally safe and protective of public
health and the environment. The
safety is ensured by the; combination
of pollutant limits and management
practices imposed by each option.
The most simple option from a
regulatory perspective is the EQ
biosolids option just described. Here,
safety is assured by imposition of
stringent pollutant, pathogen and
vector attraction reduction limits.
Such EQ biosolids materials are
marketed to, and used by, the general
public without tracking. A more
detailed, equally protective option is
the one in which less stringent
pollutant, pathogen and vector
attraction reduction alternatives are
coupled with site and crop controls
and operational standards to ensure
safe large-scale agricultural use.

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Conclusion
We hope that this discussion of the
rule and risk assessment process helps
you to understand and be more
comfortable with BPA's new standard
for beneficial use of biosolids. More
detailed discussions of the data,
assumptions, and models used in the
risk assessment process can be found
by reading the Technical Support
Documents that were issued along with
the final rule and EPA's "Guide to the
Biosolids Risk Assessment
Methodology for the EPA 503 Rule,"
EPA/832-B-93-005, which should be
completed by the end of 1994.
Additional understanding can be
gained from the preamble to the rule
and the papers written by the experts
who have assisted EPA in selecting
appropriate data, assumptions, and
models. The rule itself is described in
greater detail in EPA's "Plain English
Guide to the EPA 503 Biosolids
Rule," EPA/832-R-93-003. To help
address remaining concerns, EPA has
sponsored and will continue to
sponsor and foster research and
information sharing events, as well as
provide technical assistance and
written publications.



wmy'•	f	_ ,..


Strip-mined land in Pennsylvania reclaimed with the use of biosolids.
28



¦ -j' »

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Sources of Information
EPA Materials Available From:
Office of Water Resource
Center (OWRC)
202-260-7786 (phone)
US EPA
401 M Street SW (RC-4100)
Washington, DC 20460
Center for Environmental
Research Information (CERI)
513-569-7562 (phone)
513-569-7585 (fax)
26 West Martin Luther King
Cincinnati, OH 45268
National Technical Information
Service (NTIS)
800-553-6847 (phone)
703-487-4650 (phone)
703-321-8547 (fax)
US Dept. of Commerce
5285 Port Royal Road
Springfield, VA 22161
Education Resource Information
Center (ERIC)
614-292-6717 (phone)
614-292-0263 (fax)
C/O West Virginia University
P.O. Box 6064
Morgantown, WV 26506
EPA Materials
A Plain English Guide to the EPA 503
Biosolids Rule. USEPA Office of
Wastewater Enforcemen t and
Compliance. EPA/832-R-93-003.
June 1994. To be available in 1994
from OWRC.
POTW Sludge Sampling and Analysis
Guidance Document. USEPA Office
of Wastewater Enforcement and
Compliance (1st Edition, August
1989. Available from NTIS [PB93-
227957] and ERIC [W134]. Revised
2nd Edition Expected in 1994.
Environmental Regulations and
Technology: Control of Pathogens
and Vector Attraction in Sewage
Sludge. USEPA Office of Research
and Development. EPA/625/R-
92/013. December 1992. Available
from CERI.
Domestic Septage Regulatory
Guidance: A Guide to the EPA 503
Rule. USEPA Office of Wastewater
Enforcement and Compliance.
EPA/832-B-92-005. July 1993.
Available from OWRC, NTIS [PB94-
142155], and ERIC [W285].
A Guide to the Biosolids Risk
Assessment Methodology for the EPA
503 Rule. USEPA Office of
Wastewater Enforcement and
Compliance. EPA/832-B-93-005, To
be available late in 1994 from OWRC.

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Technical Support Document for
Land Application of Sewage Sludge,
Volumes 1 and 2. USEPA Office of
Water. Available from NTIS [PB93-
110575 and PB93-110583] and ERIC
[D734 and D735].
Technical Support Document for
Surface Disposal of Sewage Sludge.
USEPA Office of Water. Available
from NTIS [PB93-110591] and ERIC
[D757].
Technical Support Document for
Incineration of Sewage Sludge.
USEPA Office of Water. Available
from NTIS [PB93-110617] and ERIC
[D756].
Technical Support Document for
Reduction of Pathogens and Vector
Attraction in Sewage Sludge. USEPA
Office of Water. Available from
NTIS [PB93-110609] and ERIC
[D755].
Guidance for Writing Case-by-Case
Permit Requirements for Municipal
Sewage Sludge. USEPA Office of
Wastewater Enforcement and
Compliance. May 1990. Available
from NTIS [PB91-145508] and ERIC
[W126].
Guidance for Writing Permits for the
Use or Disposal of Sewage Sludge.
Draft. USEPA Office of Wastewater
Enforcement and Compliance.
Available from ERIC [W114]. Final
available from OWRC late in 1994.
30
Preparing Sewage Sludge for Land
Application or Surface Disposal: A
Guide for Preparers of Sewage
Sludge on the Monitoring, Record
Keeping, and Reporting Requirements
of the Federal Standards for the Use
of Sewage Sludge, 40 CFR Part 503.
USEPA Office of Wastewater
Enforcement and Compliance.
EPA/83 l-B-93-002a. September
1993. Available from NTIS [PB94-
102415], ERIC [W267], and OWRC.
Sewage Sludge Sampling Video,
USEPA Office of Wastewater
Enforcement and Compliance. 1993.
Available from OWRC or Regional
EPA Sewage Sludge Coordinators.
Land Application of Sewage Sludge;
A Guide for Land Appliers on the
Record Keeping and Reporting
Requirements of the Federal
Standards for the Use or Disposal of
Sewage Sludge, 40 CFR Part 503.
USEPA Office of Wastewater
Enforcement and Compliance.
EPA/831 -B-93-002b. May 1994
Available from NTIS, ERIC, and
OWRC.
Surface Disposal of Sewage Sludge:
A Guide for Owners/Operators of
Surface Disposal Facilities on the
Monitoring, Record Keeping, and
Reporting Requirements of the
Federal Standards for the Use or
Disposal of Sewage Sludge, 40 CFR
Part 503. USEPA Office of
Wastewater Enforcement and
Compliance. EPA/83 l-B-93-002c.
May 1994. Available from NTIS,
ERIC, and OWRC.

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Other Literature
Ryan, J, A., and R. L. Chaney.
1992. Regulation of Municipal
Sewage Sludge Under the Clean
Water Act Section 503: A Model
for Exposure and Risk
Assessment for MSW-Compost,
In Science and Engineering of
Composting, Hoitink and Keener,
ed, Renaissance Publications,
Worthington, OH. 1993.
Chaney, R. L. and J. A. Ryan.
1992. Heavy Metals and Toxic
Organic Pollutants in MSW-
Composts: Research Results on
Phytoavailability, Bioavailability,
Fate, Etc. Ibid.
Chaney, R.L. and J.A. Ryan.
1994. State of the Art in
Evaluating the Risks of As, Cd,
and Pb in Urban Soils for Plants,
Animals, and Humans. Proc.
Conf. Criteria for Decision
Finding in Soil Protection:
Evaluation of Arsenic, Lead, and
Cadmium in Contaminated Urban
Soils (Oct. 9-11, 1991;
Braunschweig, FRG). In Press.
Specialists to Contact
!
Beneficial Use of Piosolids
Dr. John Walker 202-260-7283
Mr, Robert Bastian 202-260-7378
Risk Assessment
Dr. Jim Ryan	513-569-7653
Dr. John Walker 202-260-7283
Risk Assessment and
Derivation of the Rule
Mr. Robert Southworth 202-260-7157
Mr. Alan Hais	202-260-1306
Permitting i
Ms. Wendy Bell 202-260-9534
Ms. Wendy Miller 202-260-3716
Compliance Monitoring
and Enforcement
Mr. Joe Theis (Enf.) 2:02-260-8185
Mr. George Gray (Cpl.) 202-260-8313
Sampling and Analysis
Ms. Cristina Gaines 202-260-6284
Mr. Joe Theis	202-260-8185
Publications;
Ms. Shade Centilla 202-260-6052
Ms. Bernita Starks 202-260-7287

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Regional Coordinators to Contact for Permitting and
Other Issues Pertaining to Ongoing Biosolids Use or
Disposal Activities
Region 1
Region 6
Thelma Hamilton
Stephanie Kordzi
JFK Federal Bldg (WMT-2111)
(6-WPM)
One Congress St.
1445 Ross Ave., #1200
Boston, MA 02203
Dallas, TX 75202-2733
617-565-3569
214-665-7520
Region 2
Region 7
Alia Roufaeal
John Dunn
26 Federal Plaza
726 Minnesota Ave.
New York, NY 10278
Kansas City, KS 66101
212-264-8663
913-551-7594
Region 3
Region 8
Ann Carkhuff
Bob Brobst
(3WM55)
(8WM-C)
841 Chestnut St.
999 18th St., Suite 500
Philadelphia, PA 19107
Denver, CO 80202-2405
215-597-9406
303-293-1627
Region 4
Region 9
Vince Miller
Lauren Fondahl
345 Courtland St., NE
75 Hawthorne St., (W-5-2)
Atlanta, GA 30365
San Francisco, CA 94105
404-347-3012
415-744-1909
Region 5
Region 10
Ash Sajjad
Dick Hetherington
(WQP-16J)
(WD-134)
77 West Jackson
1200 Sixth Ave.
Chicago, IL 60604
Seattle, WA 98101
313-886-6112
206-553-1941

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5EPA
(4204)
United States
Environmental Protection Agency
Washington, DC 20460
Official Business
Penalty for Private Use $300

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